The document discusses the sedimentation process in rectangular channels used for cassava starch production in Colombia. It evaluates particle size distribution and slurry concentration changes. The results show slurry concentrations between 0.1-6% and sedimentation rates varying between 0.82-1.44 L/S. Particles above 10 μm were efficiently retained while particles between 6.7-8.8 μm were discharged, causing environmental issues.

2.  Background:
Cassava Production Starch mainly In The northern
Region Of The Cauca a Colombian Departament, In
Small Agricultural Industrias Know As “Rollanderías”.
 Purpose And Focus:
Evaluate The Sedimentation Process Performed In
Rectangular Channels (0.3m High; 0.4m Wide; 165m
Long) Which Are generally Used In The Region.

3.  Methods
Two main components were evaluated the determination of
the change in the concentration of the slurry zone, entering
the settling zone and the determination of the particle size
distribution in the settling zone.
 Results
The Slurry Concentration During The Strainer Operation was
Between 0,1 to 6%.
The Settling Process Variation During The Process Varied
Between 0,82 to 1.44 L/S. With A Predominance Of Laminar
Flow And A Hydraulic Retention Time Greater Than 150
Minutes.

4.  Conclusion:
In The First 104m Of The Channels, Particles
Greater Than 10 μm in size were efficiently
retained, particles between 6.7 to 8.8 μm
were not retained and were discharged
into local bodies of water, generating a
great environmental problem.

5.  Background:
In Spain young people have their first sexual
intercourse at an earlier age than in other
countries; however, little is known about the
relationship between age of sexual debut and
sexual behavior in this population.
 Purpose And Focus:
Sexual practices and methods of protection are
analyzed depending on the age of sexual debut
among Spanish adolescents who are sexually
experienced (N=351). The mean age was 15.9
years (SD = .75, range: 14-18).

6.  Methods
 Three groups were formed according to The age of sexual debut
reported: early sexual debut (earlier than 15 years), average (15
years) and late (later than 15 years).
 Results
 The early sexual debut group reported further mutual
masturbation, vaginal intercourse and oral sex with a higher
number of sexual partners than the rest.
 Condom use at first intercourse, percentage of use and
consistent condom use was significantly lower in the early sexual
debut group compared to the others. Sexual debut before 15
years old was associated with increased risk of sexual infections,
deficit in condom use and increased sexual exposure.

7.  Conclusions
The findings of this study suggest that the
age of sexual debut has implications for
the sexual health in young people.