The document discusses the production of cassava starch in Colombia. It focuses on the settling process that occurs in rectangular channels used by small agricultural industries known as "rallanderías". Two main components are evaluated: the change in concentration of the slurry entering the settling zone, and the particle size distribution within the settling zone. The study finds that particles larger than 10 μm are efficiently retained in the first 104m of the channel, while particles between 6.7-8.8μm are discharged into local bodies of water, causing environmental problems.

2. The production of cassava starch in Colombia comes
mainly from the northern region of the Cauca Department
in small agricultural
industries known as “rallanderías”, in which the settling of
the slurry occurs in channels.

3. Due to the fact that the settling process determines the
capacity of the starch industry, it is important to
evaluate the sedimentation process performed in
rectangular channels (0.3m high; 0.4 m wide; 165 m
long), which are generally used in the region.

4. 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. In relation to the affluent of the channels, it was found
that the concentration of the slurry during strainer
operation was between 0.1 to 6% most of the time; the
settling of discrete particles, for which the Stokes Law
may be applied, predominated. During the settling
process, the flow varied between 0.82 to 1.44 L/s with a
predominance of laminar flow and a hydraulic retention
time greater than 150 minutes.

6. In the first 104m of the channel, particles greater
than 10 μm in size were efficiently retained;
particles between 6,7 to 8,8μm were not retained
and were discharged into local bodies of water,
generating environmental problems.

7. 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

8. 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). 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).

9. • 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.

10. Sexual debut before 15 years old was associated
with increased risk of sexual infections, deficit in
condom use and increased sexual exposure.

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