2024 State of Marketing Report – by HubspotMarius Sescu
https://www.hubspot.com/state-of-marketing
· Scaling relationships and proving ROI
· Social media is the place for search, sales, and service
· Authentic influencer partnerships fuel brand growth
· The strongest connections happen via call, click, chat, and camera.
· Time saved with AI leads to more creative work
· Seeking: A single source of truth
· TLDR; Get on social, try AI, and align your systems.
· More human marketing, powered by robots
ChatGPT is a revolutionary addition to the world since its introduction in 2022. A big shift in the sector of information gathering and processing happened because of this chatbot. What is the story of ChatGPT? How is the bot responding to prompts and generating contents? Swipe through these slides prepared by Expeed Software, a web development company regarding the development and technical intricacies of ChatGPT!
Product Design Trends in 2024 | Teenage EngineeringsPixeldarts
The realm of product design is a constantly changing environment where technology and style intersect. Every year introduces fresh challenges and exciting trends that mold the future of this captivating art form. In this piece, we delve into the significant trends set to influence the look and functionality of product design in the year 2024.
How Race, Age and Gender Shape Attitudes Towards Mental HealthThinkNow
Mental health has been in the news quite a bit lately. Dozens of U.S. states are currently suing Meta for contributing to the youth mental health crisis by inserting addictive features into their products, while the U.S. Surgeon General is touring the nation to bring awareness to the growing epidemic of loneliness and isolation. The country has endured periods of low national morale, such as in the 1970s when high inflation and the energy crisis worsened public sentiment following the Vietnam War. The current mood, however, feels different. Gallup recently reported that national mental health is at an all-time low, with few bright spots to lift spirits.
To better understand how Americans are feeling and their attitudes towards mental health in general, ThinkNow conducted a nationally representative quantitative survey of 1,500 respondents and found some interesting differences among ethnic, age and gender groups.
Technology
For example, 52% agree that technology and social media have a negative impact on mental health, but when broken out by race, 61% of Whites felt technology had a negative effect, and only 48% of Hispanics thought it did.
While technology has helped us keep in touch with friends and family in faraway places, it appears to have degraded our ability to connect in person. Staying connected online is a double-edged sword since the same news feed that brings us pictures of the grandkids and fluffy kittens also feeds us news about the wars in Israel and Ukraine, the dysfunction in Washington, the latest mass shooting and the climate crisis.
Hispanics may have a built-in defense against the isolation technology breeds, owing to their large, multigenerational households, strong social support systems, and tendency to use social media to stay connected with relatives abroad.
Age and Gender
When asked how individuals rate their mental health, men rate it higher than women by 11 percentage points, and Baby Boomers rank it highest at 83%, saying it’s good or excellent vs. 57% of Gen Z saying the same.
Gen Z spends the most amount of time on social media, so the notion that social media negatively affects mental health appears to be correlated. Unfortunately, Gen Z is also the generation that’s least comfortable discussing mental health concerns with healthcare professionals. Only 40% of them state they’re comfortable discussing their issues with a professional compared to 60% of Millennials and 65% of Boomers.
Race Affects Attitudes
As seen in previous research conducted by ThinkNow, Asian Americans lag other groups when it comes to awareness of mental health issues. Twenty-four percent of Asian Americans believe that having a mental health issue is a sign of weakness compared to the 16% average for all groups. Asians are also considerably less likely to be aware of mental health services in their communities (42% vs. 55%) and most likely to seek out information on social media (51% vs. 35%).
AI Trends in Creative Operations 2024 by Artwork Flow.pdfmarketingartwork
Creative operations teams expect increased AI use in 2024. Currently, over half of tasks are not AI-enabled, but this is expected to decrease in the coming year. ChatGPT is the most popular AI tool currently. Business leaders are more actively exploring AI benefits than individual contributors. Most respondents do not believe AI will impact workforce size in 2024. However, some inhibitions still exist around AI accuracy and lack of understanding. Creatives primarily want to use AI to save time on mundane tasks and boost productivity.
Organizational culture includes values, norms, systems, symbols, language, assumptions, beliefs, and habits that influence employee behaviors and how people interpret those behaviors. It is important because culture can help or hinder a company's success. Some key aspects of Netflix's culture that help it achieve results include hiring smartly so every position has stars, focusing on attitude over just aptitude, and having a strict policy against peacocks, whiners, and jerks.
2024 State of Marketing Report – by HubspotMarius Sescu
https://www.hubspot.com/state-of-marketing
· Scaling relationships and proving ROI
· Social media is the place for search, sales, and service
· Authentic influencer partnerships fuel brand growth
· The strongest connections happen via call, click, chat, and camera.
· Time saved with AI leads to more creative work
· Seeking: A single source of truth
· TLDR; Get on social, try AI, and align your systems.
· More human marketing, powered by robots
ChatGPT is a revolutionary addition to the world since its introduction in 2022. A big shift in the sector of information gathering and processing happened because of this chatbot. What is the story of ChatGPT? How is the bot responding to prompts and generating contents? Swipe through these slides prepared by Expeed Software, a web development company regarding the development and technical intricacies of ChatGPT!
Product Design Trends in 2024 | Teenage EngineeringsPixeldarts
The realm of product design is a constantly changing environment where technology and style intersect. Every year introduces fresh challenges and exciting trends that mold the future of this captivating art form. In this piece, we delve into the significant trends set to influence the look and functionality of product design in the year 2024.
How Race, Age and Gender Shape Attitudes Towards Mental HealthThinkNow
Mental health has been in the news quite a bit lately. Dozens of U.S. states are currently suing Meta for contributing to the youth mental health crisis by inserting addictive features into their products, while the U.S. Surgeon General is touring the nation to bring awareness to the growing epidemic of loneliness and isolation. The country has endured periods of low national morale, such as in the 1970s when high inflation and the energy crisis worsened public sentiment following the Vietnam War. The current mood, however, feels different. Gallup recently reported that national mental health is at an all-time low, with few bright spots to lift spirits.
To better understand how Americans are feeling and their attitudes towards mental health in general, ThinkNow conducted a nationally representative quantitative survey of 1,500 respondents and found some interesting differences among ethnic, age and gender groups.
Technology
For example, 52% agree that technology and social media have a negative impact on mental health, but when broken out by race, 61% of Whites felt technology had a negative effect, and only 48% of Hispanics thought it did.
While technology has helped us keep in touch with friends and family in faraway places, it appears to have degraded our ability to connect in person. Staying connected online is a double-edged sword since the same news feed that brings us pictures of the grandkids and fluffy kittens also feeds us news about the wars in Israel and Ukraine, the dysfunction in Washington, the latest mass shooting and the climate crisis.
Hispanics may have a built-in defense against the isolation technology breeds, owing to their large, multigenerational households, strong social support systems, and tendency to use social media to stay connected with relatives abroad.
Age and Gender
When asked how individuals rate their mental health, men rate it higher than women by 11 percentage points, and Baby Boomers rank it highest at 83%, saying it’s good or excellent vs. 57% of Gen Z saying the same.
Gen Z spends the most amount of time on social media, so the notion that social media negatively affects mental health appears to be correlated. Unfortunately, Gen Z is also the generation that’s least comfortable discussing mental health concerns with healthcare professionals. Only 40% of them state they’re comfortable discussing their issues with a professional compared to 60% of Millennials and 65% of Boomers.
Race Affects Attitudes
As seen in previous research conducted by ThinkNow, Asian Americans lag other groups when it comes to awareness of mental health issues. Twenty-four percent of Asian Americans believe that having a mental health issue is a sign of weakness compared to the 16% average for all groups. Asians are also considerably less likely to be aware of mental health services in their communities (42% vs. 55%) and most likely to seek out information on social media (51% vs. 35%).
AI Trends in Creative Operations 2024 by Artwork Flow.pdfmarketingartwork
Creative operations teams expect increased AI use in 2024. Currently, over half of tasks are not AI-enabled, but this is expected to decrease in the coming year. ChatGPT is the most popular AI tool currently. Business leaders are more actively exploring AI benefits than individual contributors. Most respondents do not believe AI will impact workforce size in 2024. However, some inhibitions still exist around AI accuracy and lack of understanding. Creatives primarily want to use AI to save time on mundane tasks and boost productivity.
Organizational culture includes values, norms, systems, symbols, language, assumptions, beliefs, and habits that influence employee behaviors and how people interpret those behaviors. It is important because culture can help or hinder a company's success. Some key aspects of Netflix's culture that help it achieve results include hiring smartly so every position has stars, focusing on attitude over just aptitude, and having a strict policy against peacocks, whiners, and jerks.
PEPSICO Presentation to CAGNY Conference Feb 2024Neil Kimberley
PepsiCo provided a safe harbor statement noting that any forward-looking statements are based on currently available information and are subject to risks and uncertainties. It also provided information on non-GAAP measures and directing readers to its website for disclosure and reconciliation. The document then discussed PepsiCo's business overview, including that it is a global beverage and convenient food company with iconic brands, $91 billion in net revenue in 2023, and nearly $14 billion in core operating profit. It operates through a divisional structure with a focus on local consumers.
Content Methodology: A Best Practices Report (Webinar)contently
This document provides an overview of content methodology best practices. It defines content methodology as establishing objectives, KPIs, and a culture of continuous learning and iteration. An effective methodology focuses on connecting with audiences, creating optimal content, and optimizing processes. It also discusses why a methodology is needed due to the competitive landscape, proliferation of channels, and opportunities for improvement. Components of an effective methodology include defining objectives and KPIs, audience analysis, identifying opportunities, and evaluating resources. The document concludes with recommendations around creating a content plan, testing and optimizing content over 90 days.
How to Prepare For a Successful Job Search for 2024Albert Qian
The document provides guidance on preparing a job search for 2024. It discusses the state of the job market, focusing on growth in AI and healthcare but also continued layoffs. It recommends figuring out what you want to do by researching interests and skills, then conducting informational interviews. The job search should involve building a personal brand on LinkedIn, actively applying to jobs, tailoring resumes and interviews, maintaining job hunting as a habit, and continuing self-improvement. Once hired, the document advises setting new goals and keeping skills and networking active in case of future opportunities.
A report by thenetworkone and Kurio.
The contributing experts and agencies are (in an alphabetical order): Sylwia Rytel, Social Media Supervisor, 180heartbeats + JUNG v MATT (PL), Sharlene Jenner, Vice President - Director of Engagement Strategy, Abelson Taylor (USA), Alex Casanovas, Digital Director, Atrevia (ES), Dora Beilin, Senior Social Strategist, Barrett Hoffher (USA), Min Seo, Campaign Director, Brand New Agency (KR), Deshé M. Gully, Associate Strategist, Day One Agency (USA), Francesca Trevisan, Strategist, Different (IT), Trevor Crossman, CX and Digital Transformation Director; Olivia Hussey, Strategic Planner; Simi Srinarula, Social Media Manager, The Hallway (AUS), James Hebbert, Managing Director, Hylink (CN / UK), Mundy Álvarez, Planning Director; Pedro Rojas, Social Media Manager; Pancho González, CCO, Inbrax (CH), Oana Oprea, Head of Digital Planning, Jam Session Agency (RO), Amy Bottrill, Social Account Director, Launch (UK), Gaby Arriaga, Founder, Leonardo1452 (MX), Shantesh S Row, Creative Director, Liwa (UAE), Rajesh Mehta, Chief Strategy Officer; Dhruv Gaur, Digital Planning Lead; Leonie Mergulhao, Account Supervisor - Social Media & PR, Medulla (IN), Aurelija Plioplytė, Head of Digital & Social, Not Perfect (LI), Daiana Khaidargaliyeva, Account Manager, Osaka Labs (UK / USA), Stefanie Söhnchen, Vice President Digital, PIABO Communications (DE), Elisabeth Winiartati, Managing Consultant, Head of Global Integrated Communications; Lydia Aprina, Account Manager, Integrated Marketing and Communications; Nita Prabowo, Account Manager, Integrated Marketing and Communications; Okhi, Web Developer, PNTR Group (ID), Kei Obusan, Insights Director; Daffi Ranandi, Insights Manager, Radarr (SG), Gautam Reghunath, Co-founder & CEO, Talented (IN), Donagh Humphreys, Head of Social and Digital Innovation, THINKHOUSE (IRE), Sarah Yim, Strategy Director, Zulu Alpha Kilo (CA).
Trends In Paid Search: Navigating The Digital Landscape In 2024Search Engine Journal
The search marketing landscape is evolving rapidly with new technologies, and professionals, like you, rely on innovative paid search strategies to meet changing demands.
It’s important that you’re ready to implement new strategies in 2024.
Check this out and learn the top trends in paid search advertising that are expected to gain traction, so you can drive higher ROI more efficiently in 2024.
You’ll learn:
- The latest trends in AI and automation, and what this means for an evolving paid search ecosystem.
- New developments in privacy and data regulation.
- Emerging ad formats that are expected to make an impact next year.
Watch Sreekant Lanka from iQuanti and Irina Klein from OneMain Financial as they dive into the future of paid search and explore the trends, strategies, and technologies that will shape the search marketing landscape.
If you’re looking to assess your paid search strategy and design an industry-aligned plan for 2024, then this webinar is for you.
5 Public speaking tips from TED - Visualized summarySpeakerHub
From their humble beginnings in 1984, TED has grown into the world’s most powerful amplifier for speakers and thought-leaders to share their ideas. They have over 2,400 filmed talks (not including the 30,000+ TEDx videos) freely available online, and have hosted over 17,500 events around the world.
With over one billion views in a year, it’s no wonder that so many speakers are looking to TED for ideas on how to share their message more effectively.
The article “5 Public-Speaking Tips TED Gives Its Speakers”, by Carmine Gallo for Forbes, gives speakers five practical ways to connect with their audience, and effectively share their ideas on stage.
Whether you are gearing up to get on a TED stage yourself, or just want to master the skills that so many of their speakers possess, these tips and quotes from Chris Anderson, the TED Talks Curator, will encourage you to make the most impactful impression on your audience.
See the full article and more summaries like this on SpeakerHub here: https://speakerhub.com/blog/5-presentation-tips-ted-gives-its-speakers
See the original article on Forbes here:
http://www.forbes.com/forbes/welcome/?toURL=http://www.forbes.com/sites/carminegallo/2016/05/06/5-public-speaking-tips-ted-gives-its-speakers/&refURL=&referrer=#5c07a8221d9b
ChatGPT and the Future of Work - Clark Boyd Clark Boyd
Everyone is in agreement that ChatGPT (and other generative AI tools) will shape the future of work. Yet there is little consensus on exactly how, when, and to what extent this technology will change our world.
Businesses that extract maximum value from ChatGPT will use it as a collaborative tool for everything from brainstorming to technical maintenance.
For individuals, now is the time to pinpoint the skills the future professional will need to thrive in the AI age.
Check out this presentation to understand what ChatGPT is, how it will shape the future of work, and how you can prepare to take advantage.
The document provides career advice for getting into the tech field, including:
- Doing projects and internships in college to build a portfolio.
- Learning about different roles and technologies through industry research.
- Contributing to open source projects to build experience and network.
- Developing a personal brand through a website and social media presence.
- Networking through events, communities, and finding a mentor.
- Practicing interviews through mock interviews and whiteboarding coding questions.
Google's Just Not That Into You: Understanding Core Updates & Search IntentLily Ray
1. Core updates from Google periodically change how its algorithms assess and rank websites and pages. This can impact rankings through shifts in user intent, site quality issues being caught up to, world events influencing queries, and overhauls to search like the E-A-T framework.
2. There are many possible user intents beyond just transactional, navigational and informational. Identifying intent shifts is important during core updates. Sites may need to optimize for new intents through different content types and sections.
3. Responding effectively to core updates requires analyzing "before and after" data to understand changes, identifying new intents or page types, and ensuring content matches appropriate intents across video, images, knowledge graphs and more.
A brief introduction to DataScience with explaining of the concepts, algorithms, machine learning, supervised and unsupervised learning, clustering, statistics, data preprocessing, real-world applications etc.
It's part of a Data Science Corner Campaign where I will be discussing the fundamentals of DataScience, AIML, Statistics etc.
Time Management & Productivity - Best PracticesVit Horky
Here's my presentation on by proven best practices how to manage your work time effectively and how to improve your productivity. It includes practical tips and how to use tools such as Slack, Google Apps, Hubspot, Google Calendar, Gmail and others.
The six step guide to practical project managementMindGenius
The six step guide to practical project management
If you think managing projects is too difficult, think again.
We’ve stripped back project management processes to the
basics – to make it quicker and easier, without sacrificing
the vital ingredients for success.
“If you’re looking for some real-world guidance, then The Six Step Guide to Practical Project Management will help.”
Dr Andrew Makar, Tactical Project Management
Unlocking the Power of ChatGPT and AI in Testing - A Real-World Look, present...Applitools
During this webinar, Anand Bagmar demonstrates how AI tools such as ChatGPT can be applied to various stages of the software development life cycle (SDLC) using an eCommerce application case study. Find the on-demand recording and more info at https://applitools.info/b59
Key takeaways:
• Learn how to use ChatGPT to add AI power to your testing and test automation
• Understand the limitations of the technology and where human expertise is crucial
• Gain insight into different AI-based tools
• Adopt AI-based tools to stay relevant and optimize work for developers and testers
* ChatGPT and OpenAI belong to OpenAI, L.L.C.
The document discusses various AI tools from OpenAI like GPT-3 and DALL-E 2, as well as ChatGPT. It explores how search engines are using AI and things to consider around AI-generated content. Potential SEO uses of ChatGPT are also presented, such as generating content at scale, conducting topic research, and automating basic coding tasks. The document encourages further reading on using ChatGPT for SEO purposes.
More than Just Lines on a Map: Best Practices for U.S Bike Routes
This session highlights best practices and lessons learned for U.S. Bike Route System designation, as well as how and why these routes should be integrated into bicycle planning at the local and regional level.
Presenters:
Presenter: Kevin Luecke Toole Design Group
Co-Presenter: Virginia Sullivan Adventure Cycling Association
Ride the Storm: Navigating Through Unstable Periods / Katerina Rudko (Belka G...DevGAMM Conference
Has your project been caught in a storm of deadlines, clashing requirements, and the need to change course halfway through? If yes, then check out how the administration team navigated through all of this, relocating 160 people from 3 countries and opening 2 offices during the most turbulent time in the last 20 years. Belka Games’ Chief Administrative Officer, Katerina Rudko, will share universal approaches and life hacks that can help your project survive unstable periods when there seem to be too many tasks and a lack of time and people.
This presentation was designed to provide strategic recommendations for a brand in decline. The deck also incorporates a situational assessment, including a brand identity, positioning, architecture, and portfolio strategy for the Brand.
Presentation originally created for NYU Stern's Brand Strategy course. Design by Erica Santiago & Chris Alexander.
PEPSICO Presentation to CAGNY Conference Feb 2024Neil Kimberley
PepsiCo provided a safe harbor statement noting that any forward-looking statements are based on currently available information and are subject to risks and uncertainties. It also provided information on non-GAAP measures and directing readers to its website for disclosure and reconciliation. The document then discussed PepsiCo's business overview, including that it is a global beverage and convenient food company with iconic brands, $91 billion in net revenue in 2023, and nearly $14 billion in core operating profit. It operates through a divisional structure with a focus on local consumers.
Content Methodology: A Best Practices Report (Webinar)contently
This document provides an overview of content methodology best practices. It defines content methodology as establishing objectives, KPIs, and a culture of continuous learning and iteration. An effective methodology focuses on connecting with audiences, creating optimal content, and optimizing processes. It also discusses why a methodology is needed due to the competitive landscape, proliferation of channels, and opportunities for improvement. Components of an effective methodology include defining objectives and KPIs, audience analysis, identifying opportunities, and evaluating resources. The document concludes with recommendations around creating a content plan, testing and optimizing content over 90 days.
How to Prepare For a Successful Job Search for 2024Albert Qian
The document provides guidance on preparing a job search for 2024. It discusses the state of the job market, focusing on growth in AI and healthcare but also continued layoffs. It recommends figuring out what you want to do by researching interests and skills, then conducting informational interviews. The job search should involve building a personal brand on LinkedIn, actively applying to jobs, tailoring resumes and interviews, maintaining job hunting as a habit, and continuing self-improvement. Once hired, the document advises setting new goals and keeping skills and networking active in case of future opportunities.
A report by thenetworkone and Kurio.
The contributing experts and agencies are (in an alphabetical order): Sylwia Rytel, Social Media Supervisor, 180heartbeats + JUNG v MATT (PL), Sharlene Jenner, Vice President - Director of Engagement Strategy, Abelson Taylor (USA), Alex Casanovas, Digital Director, Atrevia (ES), Dora Beilin, Senior Social Strategist, Barrett Hoffher (USA), Min Seo, Campaign Director, Brand New Agency (KR), Deshé M. Gully, Associate Strategist, Day One Agency (USA), Francesca Trevisan, Strategist, Different (IT), Trevor Crossman, CX and Digital Transformation Director; Olivia Hussey, Strategic Planner; Simi Srinarula, Social Media Manager, The Hallway (AUS), James Hebbert, Managing Director, Hylink (CN / UK), Mundy Álvarez, Planning Director; Pedro Rojas, Social Media Manager; Pancho González, CCO, Inbrax (CH), Oana Oprea, Head of Digital Planning, Jam Session Agency (RO), Amy Bottrill, Social Account Director, Launch (UK), Gaby Arriaga, Founder, Leonardo1452 (MX), Shantesh S Row, Creative Director, Liwa (UAE), Rajesh Mehta, Chief Strategy Officer; Dhruv Gaur, Digital Planning Lead; Leonie Mergulhao, Account Supervisor - Social Media & PR, Medulla (IN), Aurelija Plioplytė, Head of Digital & Social, Not Perfect (LI), Daiana Khaidargaliyeva, Account Manager, Osaka Labs (UK / USA), Stefanie Söhnchen, Vice President Digital, PIABO Communications (DE), Elisabeth Winiartati, Managing Consultant, Head of Global Integrated Communications; Lydia Aprina, Account Manager, Integrated Marketing and Communications; Nita Prabowo, Account Manager, Integrated Marketing and Communications; Okhi, Web Developer, PNTR Group (ID), Kei Obusan, Insights Director; Daffi Ranandi, Insights Manager, Radarr (SG), Gautam Reghunath, Co-founder & CEO, Talented (IN), Donagh Humphreys, Head of Social and Digital Innovation, THINKHOUSE (IRE), Sarah Yim, Strategy Director, Zulu Alpha Kilo (CA).
Trends In Paid Search: Navigating The Digital Landscape In 2024Search Engine Journal
The search marketing landscape is evolving rapidly with new technologies, and professionals, like you, rely on innovative paid search strategies to meet changing demands.
It’s important that you’re ready to implement new strategies in 2024.
Check this out and learn the top trends in paid search advertising that are expected to gain traction, so you can drive higher ROI more efficiently in 2024.
You’ll learn:
- The latest trends in AI and automation, and what this means for an evolving paid search ecosystem.
- New developments in privacy and data regulation.
- Emerging ad formats that are expected to make an impact next year.
Watch Sreekant Lanka from iQuanti and Irina Klein from OneMain Financial as they dive into the future of paid search and explore the trends, strategies, and technologies that will shape the search marketing landscape.
If you’re looking to assess your paid search strategy and design an industry-aligned plan for 2024, then this webinar is for you.
5 Public speaking tips from TED - Visualized summarySpeakerHub
From their humble beginnings in 1984, TED has grown into the world’s most powerful amplifier for speakers and thought-leaders to share their ideas. They have over 2,400 filmed talks (not including the 30,000+ TEDx videos) freely available online, and have hosted over 17,500 events around the world.
With over one billion views in a year, it’s no wonder that so many speakers are looking to TED for ideas on how to share their message more effectively.
The article “5 Public-Speaking Tips TED Gives Its Speakers”, by Carmine Gallo for Forbes, gives speakers five practical ways to connect with their audience, and effectively share their ideas on stage.
Whether you are gearing up to get on a TED stage yourself, or just want to master the skills that so many of their speakers possess, these tips and quotes from Chris Anderson, the TED Talks Curator, will encourage you to make the most impactful impression on your audience.
See the full article and more summaries like this on SpeakerHub here: https://speakerhub.com/blog/5-presentation-tips-ted-gives-its-speakers
See the original article on Forbes here:
http://www.forbes.com/forbes/welcome/?toURL=http://www.forbes.com/sites/carminegallo/2016/05/06/5-public-speaking-tips-ted-gives-its-speakers/&refURL=&referrer=#5c07a8221d9b
ChatGPT and the Future of Work - Clark Boyd Clark Boyd
Everyone is in agreement that ChatGPT (and other generative AI tools) will shape the future of work. Yet there is little consensus on exactly how, when, and to what extent this technology will change our world.
Businesses that extract maximum value from ChatGPT will use it as a collaborative tool for everything from brainstorming to technical maintenance.
For individuals, now is the time to pinpoint the skills the future professional will need to thrive in the AI age.
Check out this presentation to understand what ChatGPT is, how it will shape the future of work, and how you can prepare to take advantage.
The document provides career advice for getting into the tech field, including:
- Doing projects and internships in college to build a portfolio.
- Learning about different roles and technologies through industry research.
- Contributing to open source projects to build experience and network.
- Developing a personal brand through a website and social media presence.
- Networking through events, communities, and finding a mentor.
- Practicing interviews through mock interviews and whiteboarding coding questions.
Google's Just Not That Into You: Understanding Core Updates & Search IntentLily Ray
1. Core updates from Google periodically change how its algorithms assess and rank websites and pages. This can impact rankings through shifts in user intent, site quality issues being caught up to, world events influencing queries, and overhauls to search like the E-A-T framework.
2. There are many possible user intents beyond just transactional, navigational and informational. Identifying intent shifts is important during core updates. Sites may need to optimize for new intents through different content types and sections.
3. Responding effectively to core updates requires analyzing "before and after" data to understand changes, identifying new intents or page types, and ensuring content matches appropriate intents across video, images, knowledge graphs and more.
A brief introduction to DataScience with explaining of the concepts, algorithms, machine learning, supervised and unsupervised learning, clustering, statistics, data preprocessing, real-world applications etc.
It's part of a Data Science Corner Campaign where I will be discussing the fundamentals of DataScience, AIML, Statistics etc.
Time Management & Productivity - Best PracticesVit Horky
Here's my presentation on by proven best practices how to manage your work time effectively and how to improve your productivity. It includes practical tips and how to use tools such as Slack, Google Apps, Hubspot, Google Calendar, Gmail and others.
The six step guide to practical project managementMindGenius
The six step guide to practical project management
If you think managing projects is too difficult, think again.
We’ve stripped back project management processes to the
basics – to make it quicker and easier, without sacrificing
the vital ingredients for success.
“If you’re looking for some real-world guidance, then The Six Step Guide to Practical Project Management will help.”
Dr Andrew Makar, Tactical Project Management
Unlocking the Power of ChatGPT and AI in Testing - A Real-World Look, present...Applitools
During this webinar, Anand Bagmar demonstrates how AI tools such as ChatGPT can be applied to various stages of the software development life cycle (SDLC) using an eCommerce application case study. Find the on-demand recording and more info at https://applitools.info/b59
Key takeaways:
• Learn how to use ChatGPT to add AI power to your testing and test automation
• Understand the limitations of the technology and where human expertise is crucial
• Gain insight into different AI-based tools
• Adopt AI-based tools to stay relevant and optimize work for developers and testers
* ChatGPT and OpenAI belong to OpenAI, L.L.C.
The document discusses various AI tools from OpenAI like GPT-3 and DALL-E 2, as well as ChatGPT. It explores how search engines are using AI and things to consider around AI-generated content. Potential SEO uses of ChatGPT are also presented, such as generating content at scale, conducting topic research, and automating basic coding tasks. The document encourages further reading on using ChatGPT for SEO purposes.
More than Just Lines on a Map: Best Practices for U.S Bike Routes
This session highlights best practices and lessons learned for U.S. Bike Route System designation, as well as how and why these routes should be integrated into bicycle planning at the local and regional level.
Presenters:
Presenter: Kevin Luecke Toole Design Group
Co-Presenter: Virginia Sullivan Adventure Cycling Association
Ride the Storm: Navigating Through Unstable Periods / Katerina Rudko (Belka G...DevGAMM Conference
Has your project been caught in a storm of deadlines, clashing requirements, and the need to change course halfway through? If yes, then check out how the administration team navigated through all of this, relocating 160 people from 3 countries and opening 2 offices during the most turbulent time in the last 20 years. Belka Games’ Chief Administrative Officer, Katerina Rudko, will share universal approaches and life hacks that can help your project survive unstable periods when there seem to be too many tasks and a lack of time and people.
This presentation was designed to provide strategic recommendations for a brand in decline. The deck also incorporates a situational assessment, including a brand identity, positioning, architecture, and portfolio strategy for the Brand.
Presentation originally created for NYU Stern's Brand Strategy course. Design by Erica Santiago & Chris Alexander.
2. Evaluarea aproximativa a indicilor de toxicitate si biodegradabilitate
ai compusilor pe baza structurii chimice
Principiile generale ale metodei QSAR si metodei contributiei de grup.
Deoarece numarul de compusi chimici complecsi sintetizati este foarte mare, iar
metodele fizico-chimice-biologice de determinare a proprietatilor sunt laborioase, au
fost elaborate modele matematice semi-empirice de corelare a unor caracteristici
structurale a substantei cu aceste proprietati (toxicitate, biodegradabilitate, caldura
specifica, caldura de formare, reactivitate, etc.). Aceste metode ofera avantajul unor
relatii generalizabile ce pot prezice caracteristicile unor compusi chimici inca
nesintetizati, sau pot realiza o economie substantiala de efort de cercetare pentru
caracterizarea completa a poluantilor din mediu, substituind unele teste de laborator.
Din punctul de vedere al interesului privind caracterizarea proprietatilor substantelor
periculoase pentru mediu, aceste metode matematice, ce utilizeaza structura si
proprietatile fizico-chimice ale compusului pot realiza o serie de predictii de importanta
deosebita, cum ar fi:
- predictii ale biodegradabilitatii si toxicitatii unor substante cu structura cunoscuta, dar
pentru care nu exista date experimentale de caracterizare a proprietatilor sale, sau
aceste date nu sunt posibil de obtinut in timp real;
- predictii ale efectului combinat al mai multor poluanti prezenti simultan in mediul
analizat, sub raportul caracteristicilor de biodegradabilitate, toxicitate,
bioacumulare, pericol de incendiu sau pentru sanatate.
3. Din categoria modelelor de corelare statistica structura-proprietati substante se disting doua
tipuri de modele: QSAR (Quantitative Structure - Activity Relations) si CGFS (Contributii ale
Grupelor Functionale Structurale). Metoda QSAR coreleaza statistic o proprietate aparenta a
substantei, determinata experimental, cu parametrii structurali ai moleculei sale, folosind
modele empirice, de regula liniare si multivariabile. Dintre proprietatile substantelor cele mai
corelate sunt de mentionat:
- activitatea biologica (A);
- reactivitatea chimica (constante cinetice de viteza k, constante de echilibru K, energia
libera de reactie ΔG, entalpii de activare ΔH);
- toxicitatea (IC50, TA100, LC50, EC50, NOEC);
- biodegradabilitatea (BOD5, t½).
4. Dintre parametrii structurali moleculari folositi in corelatiile QSAR se remarca:
- parametrii de transport (hidrofobicitatea; Log-Pow; P - coef. de partitie al substantei
intr-un amestec dintre un solvent nepolar si apa la un pH dat; Pow - coef. de partitie
al substantei intr-un amestec octanol - apa la un pH dat; π X - constanta de substituent
X fata de o molecula nesubstituita (indice o), log( PX / Po ) = aπ X ; solubilitatea in apa
S, constanta Henry H, pH-ul, constanta de ionizare pKa; parametrii solvatocromici);
- parametrii efectelor electronice (inductive, mezomerice, si de rezonanta, de tip
Hammett; constante de substituent; conectivitate moleculara);
- parametrii sterici (potentiale semi-empirice Lennard-Jones, Buckingham,
raze/volum/suprafata moleculara van der Waals; coeficienti de auto-corelare volum
van der Waals; ES ,X - parametrul steric de substituent X fata de o molecula
nesubstituita (indice o), log( kX / ko ) =δ ES ,X ; indici topologici ai substantei bazati
pe matricile de adiacenta atomi si distante intre atomi; gradul de nepotrivire sterica
MTD).
- parametrii cuanto-chimici (densitate electronica atomica, ordinul legaturii chimice
intre atomi, indicele de valenta libera, polarizabilitatea atom-atom, densitatea
electronului de frontiera, ordinul de legatura de frontiera, super-delocalizabilitatea
electronica, energii de stabilizare si localizare electronica, energia celei mai inalte/joase
orbite moleculare neocupate, electronegativitatea, duritatea de activare, moment
dedipol, polarizabilitatea medie, anizotropia polarizabilitatii, campul electrostatic
molecular).
5. Metoda CGFS se bazeaza tot pe modele semi-empirice ce coreleaza proprietatile
aparente ale substantei chimice in raport cu structura chimica, mai precis cu gruparile
functionale din molecula de baza. Dintre proprietatile cele mai corelate sunt de amintit:
- reactivitatea chimica (constante cinetice de viteza k, constante de echilibru K);
- marimi termodinamice (calduri de formare Δ H f , calduri de combustie Δ Hc ,
entropia
de formare Δ S f , constante de echilibru de formare K f );
- proprietati fizice (caldura specifica Cp , viscozitate dinamica lichide / gaze η ,
conductivitate termica λ );
- biodegradabilitatea (BOD5, t½).
Modelele QSAR de corelatie empirica se construiesc in felul urmator: pentru un
numar de substante chimice Si (i = 1, 2, .... n) se cunoaste, din date experimentale, o
proprietate exprimata printr-o variabila masurabila Ai (de exemplu: reactivitatea,
activitatea biologica, toxicitatea, biodegradabilitatea, etc.). In continuare, se cauta o
relatie intre variabila masurata Ai si anumite caracteristici structurale xji (j = 1,...m) ale
substantelor (de exemplu: constante Hammett σ, parametrii de hidrofobicitate Pow, π, sau
anumite proprietati fizice). Acest model de corelatie este, de regula, liniar, prezicand un
estimat cu ajutorul relatiei:
6. unde: x1i, x2i, ... sunt variabilele / masurile cantitative ale proprietatilor / parametrilor
structurali ale substantei chimice;
a1 , a2 , ... sunt coeficienti de regresie care exprima gradul de influentare a activitatii Ai de catre
proprietatatile exprimate prin variabilele structurale x1i , x2i , .....
Calculul coeficientilor de regresie liniara se face folosind estimatori statistici clasici,iar validarea
modelului se face utilizand seturi de teste de adecvanta si de inferenta a
coeficientilor estimati.
7. Principalele dificultati si limitele de aplicare a QSAR pentru corelarea unui numar
mare de proprietati de interes practic ale substantelor, se refera la urmatoarele aspecte:
(1) Posibilitatea obtinerii unei corelari intamplatoare intre Ai si variabilele structurale
X1i ...,xmi , daca numarul m al tipurilor de parametrii structurali este prea mare, sau daca dintr-un
numar mare de parametrii posibili se alege, prin incercari repetate, un set mult prea redus de
parametrii care permite o corelare liniara buna cu datele experimentale. Pentru a evita acest
inconvenient, se recomanda m<(3-4)n , sau cel putin m<n. Pentru a verifica validitatea corelatiei
QSAR se poate proceda in mai multe moduri: (i) se testeaza capacitatea de predictie caculand
pentru compusii test, neutilizati in obtinerea ecuatiei corelationale; (ii) se aplica validarea
incrucisata, prin care se separa k1 compusi test din cei n compusi pentru care exista date
experimentale. Modelul de corelare se va stabili utilizand (n-k1) compusi, si se va testa prezis
in raport cu cei k1 compusi neutilizati in corelarea statistica. Procedura se repeta cu alti k2
compusi separati din esantion, obtinandu-se corelatia pe baza a (n-k2) compusi, si se testeaza
predictibilitatea modelului fata de cei k2 compusi neutilizati.
Procedura se repeta pana cand toti cei n compusii ajung sa faca parte din seriile test.
(2) Corelatia dintre parametrii structurali si proprietatea aparenta poate sa nu fie
aproximata satisfacator printr-un model liniar, ci necesita un model complex
(neliniar).
(3) Deoarece mecanismul actiunii biologice este complex, in cadrul unei serii de
molecule studiate, parametrii determinanti pot sa nu fie aceiasi pentru toate
moleculele.
8. (4) Mecanismul interactiei dintre efectorul (ligandul L) substantei chimice si receptorul
(R) din mediu, complexat de catre efector, este unul complex, fiind dependent de o
multitudine de caracteristici structurale ale acestor molecule, si neputand fi redat
satisfacator printr-un model QSAR simplu.
(5) Informatiile experimentale privind activitatea liganzilor si structurile moleculare ale
receptorilor sunt, in general, insuficiente pentru caracterizarea completa a procesului
de interactiune.
Mecanismul actiunii biologice.
Intr-o forma simplificata, mecanismul actiunii biologice a unei substante implica
combinarea moleculelor / grupelor functionale ale substantei (denumite ‚efectori’, sau
liganzi L), cu moleculele unui receptor din mediu (R), care poate fi o proteina, sau un
complex de molecule de pe suprafata sau din interiorul celulelor vii. Intensitatea
actiunii
biologice (A) se exprima cantitativ prin logaritmul inversului concentratiei (C) care
produce un raspuns specificat, adica:
De regula, se utilizeaza concentratia C50, adica acea concentratie molara care produce 50% din
activitatea biologica maxima. Activitatea biologica este proportionala cu afinitatea moleculei /
ligandului pentru receptorul dat.
9. In cazul mecanismului specific de actiune, liganzii pot fi clasificati ca agonisti si antagonisti ai
receptorilor. Substantele cu caracter agonist produc aceeasi actiune activanta ca si mediatorul
chimic natural, pe cand antagonistii impiedica actiunea activanta a mediatorului chimic natural.
In afara de acest mecanism specific de actiune a ligandului, exista si un mecanism nespecific,
caracteristic actiunii toxice a alcoolilor, cetonelor, aldehidelor, detergentilor, si altor tipuri de
compusi. Doza toxica pentru aceste substante (C50) corespunde unei concentratii de peste 10-3
moli/l. Aceste substante au, de regula, un coeficient de partitie Pow mare, si actioneaza prin
inhibarea transmisiei influxului nervos in membranele excitabile, prin cuplarea nespecifica la
proteinele implicate in functionarea sinapselor. Pentru astfel de compusi, A se coreleaza bine cu
Pow si cu o variabila ce indica prezenta H-polar (punti de hidrogen).
Afinitatea dintre un ligand ( Li ) si un receptor ( Rc ), poate fi corelata direct cu
activitatea biologica a substantei ce contine acel ligand, daca se considera ca este
proportionala cu gradul de complexare al receptorului Rc de catre Li. In aceasta situatie,
presupunand ca o concentratie [ Li ] produce o activitate biologica de α% (fata de
maximul admis de 100%), si aplicand legile echilibrului chimic, se obtine:
unde: Rc = receptorul; C*
= complexul activat Rc-Li ; ΔGi = entalpia libera a reactiei de
cuplare; R = constanta niversala a gazelor; T = temperatura; Ki = constanta de disociere
a complexului C*
. Daca [Li] = C50 , rezulta ca α = 50 si Ki = C50. Prin logaritmare, se
obtine relatia dintre afinitatea (Δ Gi ) receptorului pentru ligandul Li si activitatea
biologica Ai a ligandului (notatie: log = log10 = lg ):
10. Daca insa utilizam activitatile biologice relative (α) si avem aceeasi valoare a concentratiei
pentru toate moleculele ligandului ( Li = C ), se obtine:
Relatia anterioara este valabila pentru α min <α <α max (excluzandu-se valorile limita
α=0 si α=100).
Interactiunea ligand - receptor poate fi tratata formal ca o reactie enzimatica intre substrat (S) si
enzima (E), daca se considera complexul activat (ES*) drept complex biologic activ C*. In acest
caz, schema Michaelis-Menten pentru reactiile enzimatice, conduce la:
unde: [E0] = concentratia de enzima totala; [S] = concentratia de substrat.
11. Viteza specifica a reactiei enzimatice este kcat/K , si poate fi utilizata pentru determinarea
activitatii conform complexului activat din teoria lui Eyring:
(unde ΔG* = entalpia libera; a = log(kT/h); k= constanta Boltzmann; T= temperatura
absoluta; h= constanta Plank; log = log10 = lg ).
Corelarea activitatii biologice cu hidrofobicitatea si factorii sterici moleculari.
Pentru exemplificare se prezinta inhibarea prin saruri de acizi grasi (anioni) a
alcooldehidrogenazei. Daca se exprima activitatea biologica (A), cu ajutorul dozei toxice C50 :
(unde: log = log10 ), atunci ea se poate corela cu hidrofobicitatea acizilor grasi (log Pow ) si cu
constanta sterica Taft (Es), corespunzatoare radicalului hidrocarbonat, prin relatia liniara:
12. Exemple de modele QSAR de corelare a toxicitatii acute a substantelor organice
Toxicitatea la pesti (LC50) se poate corela cu hidrofobicitatea substantei si cu
factorii sterici moleculari, pe baza unui model QSAR propus de Könemann (1981),
obtinut pe culturi de Poecilia Reticulata si pentru diversi poluanti industriali. Modelul
prezinta forma generala (notatie log = log10 ):
(in care: P = Kow= constanta de partitie in n-octanol/apa; pKa = logaritmul constantei de
disociere in apa; Es= parametru steric; S= solubilitatea in apa).
Nirmalakhandan et al. (1994) si Sun et al. (1994) propun urmatoarele corelatii QSAR ale
toxicitatii pe baza conectivitatii moleculare si a datelor obtinute pe culturi comerciale de
Polytox ( IC50 in mM; notatie: log = log10 ):
13. Pedersen et al., (1994) recomanda mai multe corelatii QSAR ale toxicitatii bazate pe
Log-Pow , utile in cazul in care nu se cunosc nici un fel de alte date privind toxicitatea
substantelor. Astfel, se recomanda calculul toxicitatii acute in mediul acvatic (EC50,
LC50, mg/L), si a solubilitatii in apa (Sw , mg/L) cu ajutorul relatiilor:
14. Wolf et al. (1988) si Hermens et al. (1984) propun corelatii QSAR pentru indicatorul de
toxicitate NOEC (No-Observed-Effect-Concentrations) sau a concentratiei cea mai mare
la care nu se observa un efect toxic (exprimata in μmol/L) pe baza studiilor a mai mult
de 25 de substante utilizand Daphnia magna ca organism testat:
log 1/NOEC = 1.03 log(Pow ) − 4.43 , (efect asupra reproducerii)
log 1/NOEC = 0.99 log(Pow ) − 4.16 , (efect asupra cresterii)
log 1/EC50 = 1.03 log(Pow ) − 4.73 , (efect asupra reproducerii)
log 1/NOEC = 0.67 log(Pow ) − 2.82 , (aromate-halogenate)
log 1/EC50 = 0.69 log(Pow ) − 3.18 , (aromate-halogenate)
Daca nu exista nici un fel de date experimentale privind toxicitatea acvatica, EC
(1996) recomanda urmatoarele corelatii QSAR pentru calculul toxicitatii (in mol/L):
Polar narcosis, peste, Pimephales promelas, 96h: logLC50 = -0.73logKow − 2.16 ;
Nonpolar narcosis, peste, Pimephales promelas, 96h: logLC50 = -0.85logKow − 1.39 ;
Nonpolar narcosis, peste, Pimephales promelas, 30z: logNOEL = -0.9logKow − 2.3 ;
Nonpolar narcosis, Daphnia magna, 48h: logEC50 = -0.95logKow − 1.32 ;
Polar narcosis, Daphnia magna, 48h: logEC50 = -0.56logKow − 2.79 ;
15. Un studiu comparativ al corelatiilor QSAR privind toxicitatile IC50 ale compusilor
organici pe culturi de Nitrobacter este prezentat de Tang et al. (1992). Folosind datele
experimentale si unii parametrii structurali, s-au propus corelatii in raport cu patru categorii
de parametrii: i) coeficientul de partitie in amestec de octanol-apa, Log-Pow; ii) solubilitatea
in apa, Log-Sw; iii) parametrii solvatocromici; iv) indicii de conectivitate moleculara.
Corelatiile sunt urmatoarele (notatie:
log = log10 ):
16. Murray et al. (1975) propune corelatiile QSAR pentru calculul Log-Pow al principalilor
compusi organici. Valorile potrivite ale conectivitatii moleculare se pot gasi in literatura.
O serie de cercetari recente au urmarit compararea toxicitatii experimentale a mai
mult de 100 de substante organice testate pe patru tipuri diferite de microorganisme,
cu cea prezisa utilizand relatiile liniare QSAR folosind parametrii de solvatare-energie
(LSER), indicele de conectivitate moleculara (MCI) si coeficientii de partitie octanolapa
(Log-P). Concluziile acestui studiu sunt urmatoarele:
- modele LSER sunt, in general, cele mai precise;
- modele MCI si Log-P au fost compatibile numai pentru doua clase de
hidrocarburi, pentru alcooli si fenoli;
- in cazul a 17 hidrocarburi saturate halogenate (alcani clorurati) metoda Log-P nu
a condus la nici un model acceptabil.
MCI este cel mai usor de utilizat. Cea mai recenta forma a modelului MCI pentru mai
multe microorganisme relevante (namol activ, metanogene, nitrosomonas, nitrobacterii,
etc.) este cea liniara, adica: log P = a − b(MCI ) (in care a, b sunt coeficienti de regresie
liniara;
17. Metoda QSAR de predictie a toxicitatii cumulate a substantelor chimice
Pentru un amestec binar de poluanti, actiunea conjugata asupra unui receptor din mediu poate fi
sumarizata astfel: i) cei doi constituenti au comportamente similare sau distincte, in functie de
caracteristicile lor individuale; ii) cei doi constituenti interactioneaza sau nu, in functie de
structura si de capacitatea unuia de a modifica sau nu activitatea biologica a celuilalt. Analizand
efectele cumulate ale toxicitatilor substantelor chimice in amestecuri binare, Plackett & Hewlett,
1967 (citat de Nirmalakhandan et al., 1994) au identificat patru tipuri de comportamente:
• aditivitatea simpla (ideala), respectiv efectul toxic conjugat rezulta prin simpla sumare a
toxicitatilor individuale;
• mai mult decat aditivitate simpla, sau sinergism, respectiv efectul toxic cumulat este mai mare
decat suma toxicitatilor individuale;
• mai putin decat aditivitate simpla, sau aditivitate partiala, respectiv efectul toxic cumulat este
mai mic decat suma toxicitatilor individuale;
• neinteractiune, sau actiune independenta, respectiv efectul toxic cumulat este egal cu cel cauzat
de compusul chimic cu cea mai mare toxicitate.
18. Aceasta analiza devine complicata in cazul amestecurilor multicomponente deoarece actiunile
cumulate ale constituentilor pot fi foarte diferite. Pentru a se putea elabora un model matematic
al toxicitatii cumulate in amestecuri complexe de poluanti, si pentru cazurile in care au loc
interactiuni intre constituenti, au fost propuse patru concepte de analiza a comportamentelor
cumulate fata de un receptor comun din mediu:
- toxicitatea individuala, sau unitatea de toxicitate (TUi);
- indicele de aditivitate (AIi);
- indicele toxicitatii amestecului (MTIi);
- indicele de similaritate al compusilor (λ).
Utilizand conceptul unitatii de toxicitate, concentratia Ci a componentului i dintr-un amestec de n
compusi chimici poate fi inlocuita cu unitatea individuala de toxicitate (TUi), definita sub forma:
unde IC50, i reprezinta concentratia componentului care ar putea sa produca o inhibare a
activitatii biologice in proportie de 50 %, atunci cand actioneaza singur. La modul
general, TUi = Ci / Ci,limita poate fi inteles ca raportul dintre concentratia unui component
i intr-un amestec care cauzeaza un anumit raspuns, si concentratia care cauzeaza
acelasi raspuns cand substanta actioneaza singura. In unele exprimari, IC50 poate fi
inlocuit cu LC50, sau cu EC50. In functie de valoarea M rezultata, amestecul poate fi
caracterizat cu urmatoarea actiune toxica a constituentilor:
19. Bazat pe indicatorul M, Koenemann (1981) introduce un nou indicator, respectiv MTI,
definit prin relatia:
20. Comportamentul constituentilor unui amestec a fost clasificat dupa cum urmeaza:
Marking propune un alt indicator al amestecurilor toxice, notat cu AI (este indicele de
aditivitate), evaluabil pe baza valorilor lui M:
Comportamentul constituentilor unui amestec a fost clasificat dupa cum urmeaza:
AI = 0 → aditie simpla a toxicitatilor
AI > 0 → antagonism
AI < 0 → sinergism
21. Christensen & Chen (1989) propun un indicator de similaritate (λ) pentru analiza efectelor
cumulate de toxicitate a amestecurilor:
In cazul in care intr-un amestec se cunosc concentratiile componentilor (Ci), si concentratiile
individuale de inhibare (IC50,i), se pot evalua TUi individuali, iar λ rezulta din solutionarea
ecuatiei de mai sus. In functie de valorile obtinute, se pot trage urmatoarele concluzii:
0 < λ < 1 componenti toxici care nu interactioneaza;
λ = 1 componenti cu actiune aditiva simpla;
λ > 1 componenti cu actiune amplificata prin amestecare.
Pentru majoritatea chimicalelor care actioneaza prin mecanism simplu, aditiv, 0.87 < λ < 1.23.
22. Amestecurile omogene echi-toxice de poluanti sunt amestecuri omogene de n compusi
chimici cu aceeasi valoare a unitatii toxice pentru fiecare component (TUi). Daca se
considera valabil modelul aditiei simple a toxicitatilor individuale, atunci concentratia
componentului i din amestec poate fi determinata din valoarea individuala a IC50, i:
La modul general, daca intr-un amestec de n componenti unitatile de toxicitate (TUi) sunt
cunoscute pentru n-1 compusi, atunci concentratia celui de al n-lea component (Cp) care ar putea
induce toxicitatea finala poate fi prezisa cu ajutorul relatiei:
23. Un model evoluat al actiunii amestecurilor de toxine asupra unor receptori distincti din mediu
este prezentat de Junghans (2004). Acesta presupune doua etape de actiune a substantelor: o
actiune cumulatativa (aditiva) a compusilor cu actiune similara (CA), urmata de o actiune
independenta (IA) a grupurilor de compusi similari. Efectul biologic rezultant include, la modul
integral, procesele similare si ne-similare intr-o schema paralel-consecutiva de actiune. Daca se
considera un amestec de n substante, modelul actiunii similare CA a compusilor in fiecare din
cele 1,...,m grupe de compusi similari, respecta regula aditivitatii actiunii:
(in care: ci = concentratia componentilor individuali din amestec; ECxi = concentratia celui de al
i-lea component care, individual, cauzeaza acelasi efect cantitativ x ca si intreg amestecul; TUi =
unitatea individuala de toxicitate a compusului i). Intr-un model CA efectul rezultant este dat de
suma algebrica a efectelor componentilor.
24. Modelul cu doua etape de actiune a toxinelor (dupa Junghans, 2004). Notatii:
CA= aditivitate concentratii; IA= actiune independenta; R1,...,Rn = receptori
distincti din mediu.
25. Modelul actiunii separate si independente a compusilor cu efecte ne-similare / neasemanatoare
asupra mediului (modelul IA) evalueaza efectul rezultant cu ajutorul relatiei:
(in care: E( ci )= efectul toxic al componentului i din amestec; E( cmix )= efectul toxic
total, al amestecului). Intr-un model IA, efectul rezultant este dat de efectul individual
cel mai mare.
S-a demonstrat ca numarul de componenti din amestec joaca un rol important in ‚netezirea’
efectelor individuale.
26. Chen & Yeh (1996) concluzioneaza ca substantele toxice ce prezinta acelasi mecanism de atac al
receptorului, prezinta in amestec fie toxicitate aditiva fie subaditiva. Daca intr-un amestec de
poluanti se constata efecte sinergice serioase, aditia unui singur compus ce prezinta o panta mare
(s) a curbei doza-raspuns duce la scaderea drastica a sinergismului toxinelor. Amestecurile de
compusi ce prezinta rapoarte mari intre pantele curbelor doza-raspuns (de ex. s1 / s2 la un amestec
binar) prezinta toxicitate antagonista (de ex. toxice reactive si nereactive in amestec).
Amestecurile de compusi care prezinta pante s mici si care au un mecanism diferit de actiune
asupra receptorilor, pot duce la efecte sinergice importante. De aceea, se recomanda ca
suplimentar, sa se compare pantele curbelor doza-raspuns ale compusilor din amestecuri pentru a
se trage o concluzie mai sigura asupra toxicitatii globale. Chen & Chiou (1995) si Prakash et al.
(1996) sustin aceste concluzii prin evaluarea indicatorului de similaritate λ (gasit intre 0.13 si
1.33).
Modele de corelare a dinamicii acumularii substantelor organice in organisme
(modele de ordin unu 1CFOK).
In cazul actiunii amestecurilor de substante toxice asupra unui receptor din mediu (biota) este
important de cunoscut nu numai rezultatul, dupa un anumit timp, ci si dinamica (cinetica)
procesului, precum si bioacumularea (factorul de bioconcentrare BCF). Un astfel de model,
guvernat de o cinetica de ordinul unu, a fost propus de McCarty et al. (1992) in urma unor studii
de bioacumulare a derivatilor clor-aromatici in pesti (clor-etani, clor-etilene, clor-benzeni, clor-
fenoli). Modelul este bazat pe urmatorii parametri:
27. Modele QSAR de corelare a biodegradabilitatii substantelor organice
Diferite relatii cantitative QSAR intre biodegradabilitate (BOD5) si structura chimica au fost
propuse pe baza experimentelor pentru mai multe clase de compusi organici. Astfel, Zakarya et
al. (1993) propune corelarea BOD5 (mmol/mmol substanta) cu asa-numitii vectori de auto-
corelare folositi drept descriptori moleculari Vo −V7 : volumul van der Waals, lectronegativitatea,
legaturi de hidrogen, liofilicitatea.
28. Un indicator uzual al biodegradabilitatii unui compus este timpul sau de injumatatire (t½) in
conditii aerobe (testul OECD). O corelatie empirica recomandata de Koller (2000), este:
Considerand doar etapa consumului cu viteza constanta de oxigen, respectiv portiunea liniara din
graficul log( BOD) = f ( t ), se poate corela viteza de consum astfel:
29. Cea mai simpla forma de corelare prin tehnica contributiei de grup este cea liniara, de forma:
Majoritatea metodelor aproximative QSAR de evaluare a caracteristicilor de toxicitate si
biodegradabilitate ale compusilor pe baza structurii chimice utilizeaza indicatorul Kow = Pow =
coeficient de partitie al substantei intr-un amestec n-octanol/apa. Valorile acestui indicator se
determina experimental si se gasesc tabelate in literatura pentru o gama larga de compusi
poluanti O baza de date cuprinzatoare a valorilor Kow este KowWin a SRC (Syracuse Research
Corporation), consituita prin utilizarea metodei contributiei de grup, si avand o precizie de
evaluare de 0.01. In general, Pow este corelat cu una din proprietatile aparente ale substantei (de
ex. coeficienti de activitate, solubilitate, indici de refractie), proprietatile mediului (temperatura,
pH), sau structura chimica (grupuri functionale, legaturi chimice, conectivitati moleculare, etc.).
De pilda corelarea Log-P cu solubilitatea in apa a substantei (ξ) se face cu ajutorul relatiei:
30. in care m,n sunt coeficienti de corelatie
In cazul in care nu se dispun insa de date de corelare a proprietatilor fizice cu Log-P, o metoda
des utilizata este aceea a determinarii semi-empirice pe baza „contributiei de grup” (Pedersen et
al. 1994). In acesata abordare, se evaluaeaza contributia grupurilor functionale (parametrii
structurali α) ai compusului respectiv la realizarea valorii globale Log-P. Relatiile de corelare
propuse in literatura sunt de forma liniara (log = log10 ):
(in care: N j = numarul de grupe functionale de tip j; α j = contributia grupului de tip j;
n= numarul total de grupuri functionale; ε = constanta de corelare).
31. Alte modele QSAR de corelare a proprietatilor substantelor toxice
Entalpia de descompunere ( Hdecomp , kJ/mol) poate fi evaluata pe baza metodei
contributiei grupelor functionale din structura compusului, pe baza relatiei de sumare
descrisa anterior, si a contributiilor grupurilor functionale.
Clasa NFPA de inflamabilitate (National Fire Protection Agency), se poate determina pe baza
punctului de aprindere (fp – flashpoint)
Indicatorul de impact ambiental (‚environmental fate’), este definit pe baza teoriei Mackay
(1991), ca fiind fractiile molare ale substantei toxice la echilibru in cele trei medii (aer, apa,
sol). Substanta intra continuu in sistem si este degradata continuu in cele trei-faze, obtinandu-se
o stare cvasi-stationara caracterizata de compozitii constante in cele trei medii. La echilibru,
modelele QSAR de corelatie empirica sunt urmatoarele (Koller, 2000):