1) The study examined the effects of light exposure at night on cognitive function in fruit flies. Flies were exposed to either dark nights or light at night for one week and then tested in a T-maze to assess learning.
2) Flies exposed to dark nights learned to suppress their natural attraction to light in the T-maze better than flies exposed to light at night, indicating light at night disrupted cognitive function.
3) No differences were found between the groups in basic locomotion or initial light attraction, suggesting the effect was on learning and memory rather than other behaviors.
Strategies for reducing the risk of radiation for astronauts in space mission...SMJ Mortazavi
Exposure to high levels of space radiation and microgravity are two important concerns which need to be addressed before any long-term manned space mission. There are also reports showing that microgravity, through a synergistic effect, increases the radiation susceptibility of living organisms. Other researchers as well as our team have conducted some experiments on design and fabrication of appropriate radiation shields for spacecrafts. However, due to some cardinal barriers such as weight limitations and extreme inadequacy of current physical shields during extravehicular activity, we strongly believe that the physical shielding alone cannot solve the problem of potential exposure to high levels of radiation in a long-term space mission.
Therefore, over the past several years, we focused on two solutions; radioadaptive response and other biological-based radiation protection methods. Adaptive response, that is the increased radioresistance in cells or living organisms pre-exposed to a low adapting dose and then exposed to a high challenging dose, was firstly proposed by our team in 2003 as an effective method. This novel idea later formed the basis of many space radiation biology projects around the world.
Furthermore, conventional radioprotectors cannot efficiently be used in space due to limitations such as their considerable toxicity and the very narrow time window for their effective use (radioprotectors should be used before or at the time of exposure, while astronauts cannot estimate their doses before a solar particle event). Therefore, we focused on introducing natural radiation mitigators which could be efficiently used several hours after exposure (e.g. when a solar particle event subsides and astronauts are able to estimate their doses). In these experiments, radiation mitigators were introduced by our team which could be used even 24 hours after exposure to high levels of radiation caused by unpredictable sources such as SPEs.
Finally, some of our recent experiments were aimed at finding methods which could lead to boosting the immune system of astronauts during long-term missions. We investigated the effect of RF-EMFs-induced adaptive responses on immune system modulation in a mouse model of hindlimb unloading (HU). Hindlimb unloading rodent model is widely accepted by the scientific community as the model of choice for simulating spaceflight. In this study, serum levels of T helper cytokines were determined in HU mice, RF-EMF treated mice and HU mice pre-exposed to RF-EMF compared to those of untreated controls. The findings of this study will be published soon.
How does biological protection help astronauts tolerate high levels of radiationSMJ Mortazavi
Abstract:
Exposure to high levels of space radiation and microgravity are two important concerns which need to be addressed before any long-term manned space mission. There are also reports showing that microgravity, through a synergistic effect, increases the radiation susceptibility of living organisms. Other researchers as well as our team have conducted some experiments on design and fabrication of appropriate radiation shields for spacecrafts. However, due to some cardinal barriers such as weight limitations and extreme inadequacy of current physical shields during extravehicular activity, we strongly believe that the physical shielding alone cannot solve the problem of potential exposure to high levels of radiation in a long-term space mission.
Therefore, over the past several years, we focused on two solutions; radioadaptive response and other biological-based radiation protection methods. Adaptive response, that is the increased radioresistance in cells or living organisms pre-exposed to a low adapting dose and then exposed to a high challenging dose, was firstly proposed by our team in 2003 as an effective method. This novel idea later formed the basis of many space radiation biology projects around the world.
Furthermore, conventional radioprotectors cannot efficiently be used in space due to limitations such as their considerable toxicity and the very narrow time window for their effective use (radioprotectors should be used before or at the time of exposure, while astronauts cannot estimate their doses before a solar particle event). Therefore, we focused on introducing natural radiation mitigators which could be efficiently used several hours after exposure (e.g. when a solar particle event subsides and astronauts are able to estimate their doses). In these experiments, radiation mitigators were introduced by our team which could be used even 24 hours after exposure to high levels of radiation caused by unpredictable sources such as SPEs.
Finally, some of our recent experiments were aimed at finding methods which could lead to boosting the immune system of astronauts during long-term missions. We investigated the effect of RF-EMFs-induced adaptive responses on immune system modulation in a mouse model of hindlimb unloading (HU). Hindlimb unloading rodent model is widely accepted by the scientific community as the model of choice for simulating spaceflight. In this study, serum levels of T helper cytokines were determined in HU mice, RF-EMF treated mice and HU mice pre-exposed to RF-EMF compared to those of untreated controls. The findings of this study will be published soon.
Modeling the Effects of Land Use Change on FloodingAdam Nayak
Due to population growth, urban areas in Oregon have been expanding, leading to increases in impervious surfaces and net losses in wetlands, riparian vegetation, and forestation in the Northwest. Utilizing ArcGIS and NOAA’s C-CAP imagery, this study classifies and analyzes urban land use changes between 1996 and 2010. These findings shed light on the importance of land use management in urban settings and are being used by local watershed councils to advocate for changes within their stream basins.
Strategies for reducing the risk of radiation for astronauts in space mission...SMJ Mortazavi
Exposure to high levels of space radiation and microgravity are two important concerns which need to be addressed before any long-term manned space mission. There are also reports showing that microgravity, through a synergistic effect, increases the radiation susceptibility of living organisms. Other researchers as well as our team have conducted some experiments on design and fabrication of appropriate radiation shields for spacecrafts. However, due to some cardinal barriers such as weight limitations and extreme inadequacy of current physical shields during extravehicular activity, we strongly believe that the physical shielding alone cannot solve the problem of potential exposure to high levels of radiation in a long-term space mission.
Therefore, over the past several years, we focused on two solutions; radioadaptive response and other biological-based radiation protection methods. Adaptive response, that is the increased radioresistance in cells or living organisms pre-exposed to a low adapting dose and then exposed to a high challenging dose, was firstly proposed by our team in 2003 as an effective method. This novel idea later formed the basis of many space radiation biology projects around the world.
Furthermore, conventional radioprotectors cannot efficiently be used in space due to limitations such as their considerable toxicity and the very narrow time window for their effective use (radioprotectors should be used before or at the time of exposure, while astronauts cannot estimate their doses before a solar particle event). Therefore, we focused on introducing natural radiation mitigators which could be efficiently used several hours after exposure (e.g. when a solar particle event subsides and astronauts are able to estimate their doses). In these experiments, radiation mitigators were introduced by our team which could be used even 24 hours after exposure to high levels of radiation caused by unpredictable sources such as SPEs.
Finally, some of our recent experiments were aimed at finding methods which could lead to boosting the immune system of astronauts during long-term missions. We investigated the effect of RF-EMFs-induced adaptive responses on immune system modulation in a mouse model of hindlimb unloading (HU). Hindlimb unloading rodent model is widely accepted by the scientific community as the model of choice for simulating spaceflight. In this study, serum levels of T helper cytokines were determined in HU mice, RF-EMF treated mice and HU mice pre-exposed to RF-EMF compared to those of untreated controls. The findings of this study will be published soon.
How does biological protection help astronauts tolerate high levels of radiationSMJ Mortazavi
Abstract:
Exposure to high levels of space radiation and microgravity are two important concerns which need to be addressed before any long-term manned space mission. There are also reports showing that microgravity, through a synergistic effect, increases the radiation susceptibility of living organisms. Other researchers as well as our team have conducted some experiments on design and fabrication of appropriate radiation shields for spacecrafts. However, due to some cardinal barriers such as weight limitations and extreme inadequacy of current physical shields during extravehicular activity, we strongly believe that the physical shielding alone cannot solve the problem of potential exposure to high levels of radiation in a long-term space mission.
Therefore, over the past several years, we focused on two solutions; radioadaptive response and other biological-based radiation protection methods. Adaptive response, that is the increased radioresistance in cells or living organisms pre-exposed to a low adapting dose and then exposed to a high challenging dose, was firstly proposed by our team in 2003 as an effective method. This novel idea later formed the basis of many space radiation biology projects around the world.
Furthermore, conventional radioprotectors cannot efficiently be used in space due to limitations such as their considerable toxicity and the very narrow time window for their effective use (radioprotectors should be used before or at the time of exposure, while astronauts cannot estimate their doses before a solar particle event). Therefore, we focused on introducing natural radiation mitigators which could be efficiently used several hours after exposure (e.g. when a solar particle event subsides and astronauts are able to estimate their doses). In these experiments, radiation mitigators were introduced by our team which could be used even 24 hours after exposure to high levels of radiation caused by unpredictable sources such as SPEs.
Finally, some of our recent experiments were aimed at finding methods which could lead to boosting the immune system of astronauts during long-term missions. We investigated the effect of RF-EMFs-induced adaptive responses on immune system modulation in a mouse model of hindlimb unloading (HU). Hindlimb unloading rodent model is widely accepted by the scientific community as the model of choice for simulating spaceflight. In this study, serum levels of T helper cytokines were determined in HU mice, RF-EMF treated mice and HU mice pre-exposed to RF-EMF compared to those of untreated controls. The findings of this study will be published soon.
Modeling the Effects of Land Use Change on FloodingAdam Nayak
Due to population growth, urban areas in Oregon have been expanding, leading to increases in impervious surfaces and net losses in wetlands, riparian vegetation, and forestation in the Northwest. Utilizing ArcGIS and NOAA’s C-CAP imagery, this study classifies and analyzes urban land use changes between 1996 and 2010. These findings shed light on the importance of land use management in urban settings and are being used by local watershed councils to advocate for changes within their stream basins.
Information on how to create a presentation site for the Sigma Xi Student Research Showcase. The Student Showcase is a competition for virtual research presentations in all fields of science and engineering hosted by Sigma Xi, The Scientific Resarch Society.
More information at www.sigmaxi.org
The SlideShare 101 is a quick start guide if you want to walk through the main features that the platform offers. This will keep getting updated as new features are launched.
The SlideShare 101 replaces the earlier "SlideShare Quick Tour".
How to Become a Thought Leader in Your NicheLeslie Samuel
Are bloggers thought leaders? Here are some tips on how you can become one. Provide great value, put awesome content out there on a regular basis, and help others.
Se describe cómo la retina envía señales por más de una vía en el cerebro. La mayor parte de la información viaja a través del tálamo a la corteza visual y luego a las regiones que llevan a cabo el procesamiento consciente. Sin embargo, algunos datos divergen en el centro motor y el núcleo supraquiasmático, el reloj biológico del cuerpo, lo que permite a ciertos individuos ciegos poseer una habilidad inconsciente para sortear obstáculos.
Information on how to create a presentation site for the Sigma Xi Student Research Showcase. The Student Showcase is a competition for virtual research presentations in all fields of science and engineering hosted by Sigma Xi, The Scientific Resarch Society.
More information at www.sigmaxi.org
The SlideShare 101 is a quick start guide if you want to walk through the main features that the platform offers. This will keep getting updated as new features are launched.
The SlideShare 101 replaces the earlier "SlideShare Quick Tour".
How to Become a Thought Leader in Your NicheLeslie Samuel
Are bloggers thought leaders? Here are some tips on how you can become one. Provide great value, put awesome content out there on a regular basis, and help others.
Se describe cómo la retina envía señales por más de una vía en el cerebro. La mayor parte de la información viaja a través del tálamo a la corteza visual y luego a las regiones que llevan a cabo el procesamiento consciente. Sin embargo, algunos datos divergen en el centro motor y el núcleo supraquiasmático, el reloj biológico del cuerpo, lo que permite a ciertos individuos ciegos poseer una habilidad inconsciente para sortear obstáculos.
Characterizing the Effect of Static Magnetic Fields on C. elegans Using Micro...Iowa State University
In nature, several organisms possess a magnetic compass to navigate or migrate them to desired locations. It is thought that these organisms may use biogenic magnetic matter or light-sensitive photoreceptors to sense and orient themselves in magnetic fields. To unravel the underlying principles of magnetosensitivity and magnetoreception, previous experiments have been conducted on bacteria, vertebrates, crustaceans, and insects. In this study, the model organism, C. elegans, is used to test their response and sensitivity to static magnetic fields in the range of 5 milli Tesla to 120 milli Tesla. Single wild-type C. elegans are put in microfluidic channels and exposed to permanent magnets for five cycles of thirty-second time intervals. The worm movement is recorded and analyzed with custom software to calculate the average velocity and the percentage of turning and curling. Contrary to some published studies, our results did not show a significant difference compared to control experiments. This suggests that C. elegans may not sense static magnetic fields in the range of field strengths that we tested.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
Toxic effects of heavy metals : Lead and Arsenicsanjana502982
Heavy metals are naturally occuring metallic chemical elements that have relatively high density, and are toxic at even low concentrations. All toxic metals are termed as heavy metals irrespective of their atomic mass and density, eg. arsenic, lead, mercury, cadmium, thallium, chromium, etc.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Salas, V. (2024) "John of St. Thomas (Poinsot) on the Science of Sacred Theol...Studia Poinsotiana
I Introduction
II Subalternation and Theology
III Theology and Dogmatic Declarations
IV The Mixed Principles of Theology
V Virtual Revelation: The Unity of Theology
VI Theology as a Natural Science
VII Theology’s Certitude
VIII Conclusion
Notes
Bibliography
All the contents are fully attributable to the author, Doctor Victor Salas. Should you wish to get this text republished, get in touch with the author or the editorial committee of the Studia Poinsotiana. Insofar as possible, we will be happy to broker your contact.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
1. Light at Night: Cognitive Disrupter
Light at Night: Cognitive Disruptor
in Drosophila melanogaster
Justin Nelson
Dublin Coffman High School
2. Introduction
By the 1930’s most houses in the US had electricity.
For the first time in history, humans were being
exposed to artificial light at night.
The recently published “World Atlas of Artificial Night
Sky Brightness” documents that greater than 80% of
world’s people live under light polluted skies (Falchi et
al., 2016).
There has not been a comparable study of house-hold
light levels at night, but technological advances have
increased the number of light sources that are now
standard in our homes.
3. Thus, with the evolution of lighting over the past 100 years…
……there has been an increase in night-time exposure to light
4. Other Modern Night-Time Sources of Light Exposure
Until recently, it was assumed by most people that light at night was innocuous.
However, chronic exposure to light at night is now hypothesized to increase risk
for several serious health conditions
5. Rationale for Current Study: Chronic exposure to light at night
over years has been linked to cancer, heart disease and
obesity in older adults. However, short-term effects on
younger individuals have not been studied. Thus, the goal of
the study became to determine whether a week of light at
night exposure could affect brain function; cognitive function
was chosen because of its critical function in daily life and the
existence of well-described cognitive tests in many species.
Comparative Question: Does light exposure at night affect
cognitive function in Drosophila melanogaster (fruit flies)?
7. Rationale: Chronic exposure to light at night has been linked
to cancer, heart disease and obesity in older adults. However,
short-term effects on younger individuals have not been
studied.
Comparative Question: Does light exposure at night affect
cognitive function in Drosophila melanogaster (fruit flies)?
Hypothesis: If light at night impairs cognitive function, then
flies exposed to light at night will take longer to learn
suppression of a positive phototaxic response in a T-maze
than flies maintained in the dark nights.
8. What Is Positive Phototaxis and How Does a T-Maze Work?
The T-maze exploits a fly’s normal positive phototaxic
response. It gives the fly a choice between spending time
in a lighted arm and a darker arm. Most flies prefer the
lighted arm, so they will cross over to it quickly and stay
there. However, if a sufficiently aversive stimulus is added
to the light side (for example, very bitter quinine), then
flies learn to suppress the phototaxic response and will
not cross over into the lighted arm. There are eight 2-
minute trials.
Positive phototaxis means that flies will
walk toward light. This is a normal,
natural behavior.
9. Experimental Design
Flies purchased from
Carolina Biological
emerge from pupa and
are sexed and
separated into tubes
with same sex flies.
Day 0 ~ week 1
Culture tubes are
randomly assigned
to dark nights (DN;
0 lux for 12 h) or
light at night (LAN;
5 lux for 12h).
~ week 2
Flies tested in T-
maze for positive
phototaxic response
and learned
suppression of
phototaxic response
7 nights
of DN or LAN
10. Four Experimental Groups:
Dark Night Males (DN; n=8)
Dark Night Females (DN ; n=8)
Light at Night Males (LAN; n=8)
Light at Night Females (LAN; n=8)
Experimental Design
Screening for Positive Phototaxis
(movement toward light)
Trials 1-8 in T-maze
(light arm paired with diet quinine water, dark arm
paired with water. The quinine and water are added
to Whatman paper placed in the arms of the maze)
Retention Trial
4 h after Trial 8, no pairing
with quinine or water
11. Experimental Design
Independent Variables: Night-time light exposure and sex
Controlled Variables: Age, culture tube preparation, same “blinded”
experimenter, time of day for testing (3:30-6:30 pm)
Dependent Variables: latency to cross into the lighted tube (sec) and total time
spent in the lighted tube during each 2 min trial (sec).
12. Positive phototaxis is movement toward light and is a normal behavior for flies.
There were no significant group differences in latency to cross into the lighted
arm of the T-maze on the first trial (P>0.05; n=8/group; mean + SEM). These
data suggest that phototaxis is comparable among the experimental groups.
The data were analyzed using analysis of variance (ANOVA).
13. Across training trials in the T-maze, there was a significant increase in latency
to cross into the lighted arm which had bitter quinine on the Whatman paper
(P<0.01; n=8/group; mean + SEM) among dark night (DN) flies relative to light
at night (LAN) flies. These data suggest that the DN flies learned to suppress
phototaxis better than the LAN flies. There was no sex differences in behavior.
The data were analyzed by two way repeated measures ANOVA.
Improvingtaskperformance
Increase in
latency across
trials suggests
the DN flies
learned to avoid
lighted arm
No increase in
latency across
trials suggests
the LAN flies did
not learn to
avoid lighted
arm
14. Across training trials in the T-maze, there was a significant decrease in total
time spent in the lighted arm (P<0.01) among dark night (DN) flies relative to
light at night (LAN) flies. Together, these data suggest that the DN flies learned
to suppress phototaxis better than the LAN flies. There was no sex difference in
behavior. The data were analyzed by two way repeated measures ANOVA.
Improvingtaskperformance
The decrease in
latency across
trials suggests
the DN flies
learned to avoid
lighted arm
No decrease in
duration across
trials suggests
the LAN flies did
not learn to
avoid lighted
arm
15. Retention of the Task (4 hours later). During the 60 second retention task, the
latency to cross into the lighted arm was significantly shorter for the LAN flies
than the DN flies (P<0.01; mean + SEM). There was no sex difference in
performance of this task. The data were analyzed by ANOVA.
16. Experimental Design
Negative Geotaxis: Movement away from Earth’s gravitational pull.
Goal: To determine whether general locomotor is altered in response to
exposure to light at night. It is important to rule out potential locomotor
differences among experimental groups in a cognitive task that requires
locomotor behavior.
Procedure: Ten flies are placed in a culture tube that is lightly tapped until
all are on the floor of the tube, then the percent of flies that cross a line 6
cm up within 10 sec is recorded.
0 sec ~2 sec ~5 sec
17. There were no significant group differences in negative geotaxis (P>0.05;
n=30/group; mean + SEM). More than 90% of the flies in each group crossed the
line within 10 sec. These data suggest that locomotor activity is comparable
among the groups. The data were analyzed using Chi Square statistical test.
18. Conclusions:
Flies kept in dark nights (DN) learned to suppress positive phototaxic
behavior when the light was paired with bitter diet quinine water.
Flies exposed to light at night (LAN) displayed cognitive deficits in both
learning and retaining the suppression of photopositive behavior
relative to DN flies.
There were no sex differences in the learning task.
LAN did not significantly affect positive phototaxic behavior or negative
geotaxis.
Implication: Light at night is not necessarily an innocuous
stimulus and even a relatively short exposure can affect
behavior. The effects of light at night on a wide range of
human behaviors and health measures should be studied.
19. Future Directions:
To determine if some wavelengths of light are less detrimental than others. For
example, red light (~650 nanometers) at night does not alter circadian rhythms.
To expand the study to test other types of cognition, as well as assess other
behaviors, such as aggression, depression, and circadian patterns of activity.
Also, in a preliminary study I weighted some of the flies. There was no difference
between the mean body masses of DN and LAN males, which were
approximately 75% of the mean body mass of DN females (this sex difference is
expected), but only 50% of the body weight of LAN females. In other words, LAN
females had higher average body mass than all other groups. One of the
negative health consequences of LAN in humans is obesity; surprisingly obesity
can also be studied in flies. I would like to determine why there was a sex
difference in LAN effects on body mass and how LAN is changing growth curves.
20. Thank You!
Dr. Courtney DeVries for sponsoring my project.
Dr. Zach Weil for providing suggestions and feedback.
Dr. John Chaston for lending me the maze after I
wrote to ask him for dimensions so I could 3-D print
one (most other people I emailed about dimensions
didn’t respond)
My parents for not getting mad when some flies
escaped into our house….
21. References:
1) Aceves-Pina et al., 1983. Learning and Memory in Drosophila, Studied with Mutants. Cold Spring Harbor Symposium on
Quantitative Biology, 48: 831-840.
2) Le Bourg E, Buecher C. 2002. Learned suppression of photopositive tendencies in Drosophila melanogaster. Animal Learning
and Behavior, 30(4):330-41.
3) Carolina Drosophila Manual 2005.
4) Falchi F, Cinzano P, Duriscoe D, Kyba CC, Elvidge CD, Baugh K, Portnov BA, Rybnikova NA, Furgoni R. 2016. The new world atlas
of artificial night sky brightness. Science Advances, 2(6):e1600377.
5) Davis S, Mirick DK, Stevens RG. 2001. Light at Night, Shiftwork, and Breast Cancer Risk. Journal of the National Cancer Institute,
93(20):1557-62.
6) Hansen et al., 2001. Light at Night, Shiftwork, and Breast Cancer Risk. Journal of the National Cancer Institute, 93: 1513-1515.
7) Le Bourg E, Buecher C. 2002. Learned suppression of photopositive tendencies in Drosophila melanogaster. Animal Learning
and Behavior, 30:330-41.
8) McFadden E, Jones ME, Schoemaker MJ, Ashworth A, Swerdlow AJ. 2014. The relationship between obesity and exposure to
light at night: cross-sectional analyses of over 100,000 women in the Breakthrough Generations Study. American Journal of
Epidemiology, 180(3):245-50.
9) Quinn WG, Harris WA, Benzer S. 1974. Conditioned behavior in Drosophila melanogaster. Proceedings National Academy
Sciences U S A. 71(3):708-12.
10) Rybnikova NA, Haim A, Portnov BA. 2016. Does artificial light-at-night exposure contribute to the worldwide obesity
pandemic? International Journal of Obesity, 40(5):815-23.
11) Smith WW, Thomas J, Liu J, Li T, Moran TH. 2014. From fat fruit fly to human obesity. Physiology Behavior. 136:15-21.
12) Stevens RG, Zhu Y 2015. Electric light, particularly at night, disrupts human circadian rhythmicity: is that a problem? Philos
Trans R Soc Lond B Biol Sci. 370(1667).
Photo credits:
1) Alamy Stock Photos: Earth picture, and associated fly picture. Two pictures
merged by Justin Nelson using Affinity Photo Software.
2) Shutterstock Photos: Fly on leaf and light bulbs.
3) Justin Nelson: all other photos and videos.