This document summarizes two studies. The first study evaluated the sedimentation process of cassava starch in rectangular channels used in Colombian agriculture. It found that the slurry concentration during operation was usually between 0.1-6% and that discrete particle settling predominated. Particles between 6.7-8.8um were discharged into local water bodies, causing environmental issues. The second study analyzed Spanish adolescents' sexual practices and protection methods depending on their age of sexual debut. It found that debut before 15 was associated with increased risk of infection, less condom use, and more sexual partners.

2. Cassava Starch Separation
The parts:
-Background
-Purpose ando focus
-Methods
-Results
-Conclusions
Abstract: Cassava Starch Separation
Background:
The production of the cassava starch in Colombia comes
mainly from the nothern region of the Cauca
Departament in small agricultural industries know as
“rallanderias”, in wichi the settling of the slurry accurs in
channels.

3. Purpose and focus
It is important to evaluate the
sedimentation process performed in
rectangular channels (0.3 high; 0.4
wide; 165 m long), wich are generally
used in the region.

4. Methods
Two main components were evaluated:
determination of the change in the
concentration of the slurry entering the
settling zone and determination of the particle
size distribution in the settling zone.

5. Results
It was found that the concentracion of the
slurry during strainer operation was between
0.1 to 6% most of the time; the settling of
discrete particles, for wich to Stokes Law may
be applied, predominated.

6. Conclusions
Particles between 6.7 to 8.8 um were not
retained and were discharged into local bodies
of water, generating environmental problems

7. Sexual Risk in adolescents dependin on the age of sexual debut
Background
In Spain young people have their first sexual intercourse at an
earlier age than in other countries.
Purpose and focus
Sexual practices and methods of protection are analyzed
depending on the age of sexual debut among spanis
adolescents who are sexually experienced. The mean age was
15,9 years.

8. Methods
The early sexual debut group reported further
mutual masturbation, original intercourse
and oral sex with a higher number of sexual
patners than the rest.

9. Results
Sexual debut before 15 years old was
associated with increased risk of sexual
infections, deficit in condom use and
increased sexual expore.
Conclusions
The findings of this estudy suggest that the
age of sexual debut has implication for the
sexual health in young people.