994 resultados para Different precursors
Resumo:
Some antibullying interventions have shown positive outcomes with regard to reducing violence. The aim of the study was to experimentally assess the effects on school violence and aggressiveness of a program to prevent and reduce cyberbullying. The sample was comprised of a randomly selected sample of 176 adolescents (93 experimental, 83 control), aged 13-15 years. The study used a repeated measures pre-posttest design with a control group. Before and after the program, two assessment instruments were administered: the "Cuestionario de Violencia Escolar-Revisado" (CUVE-R [School Violence Questionnaire- Revised]; Alvarez Garcia et al., 2011) and the "Cuestionario de agresividad premeditada e impulsiva" (CAPI-A [Premeditated and Impulsive Aggressiveness Questionnaire]; Andreu, 2010). The intervention consisted of 19 one-hour sessions carried out during the school term. The program contains 25 activities with the following objectives: (1) to identify and conceptualize bullying/cyberbullying; (2) to analyze the consequences of bullying/cyberbullying, promoting participants' capacity to report such actions when they are discovered; (3) to develop coping strategies to prevent and reduce bullying/cyberbullying; and (4) to achieve other transversal goals, such as developing positive variables (empathy, active listening, social skills, constructive conflict resolution, etc.). The pre-posttest ANCOVAs confirmed that the program stimulated a decrease in: (1) diverse types of school violence teachers' violence toward students (ridiculing or publicly humiliating students in front of the class, etc.); students' physical violence (fights, blows, shoves... aimed at the victim, or at his or her property, etc.); students' verbal violence (using offensive language, cruel, embarrassing, or insulting words... toward classmates and teachers); social exclusion (rejection or exclusion of a person or group, etc.), and violence through Information and Communication Technologies (ICT; violent behaviors by means of electronic instruments such as mobile phones and the Internet); and (2) premeditated and impulsive aggressiveness. Pre-posttest MANCOVA revealed differences between conditions with a medium effect size. This work contributes an efficacious intervention tool for the prevention and reduction of peer violence. The conclusions drawn from this study have interesting implications for educational and clinical intervention.
Resumo:
The hatching rates of African catfish (Clarias gariepinus) eggs on four natural substrates: the roots of Nile cabbage (Pistia stratiotes), water hyacinth (Eichhornia crassipes), pond weed (Ceratophyllum dermasum) and green grass leaves (Commelina sp.), and four artificial substrates: sisal mats, nylon mats, papyrus mats and kakaban mats, was assessed. Concrete slabs were used as control. The natural substrates performed better than the artificial ones. Pistia roots gave the best mean hatching rate of 66.2 ± 3.62%. Green grass leaves were second with a mean rate of 54.0 ± 3.46%, water hyacinth was third with 49.7 ± 3.16% and Ceratophyllum fourth with a mean of 13.0 ± 2.37%. Concrete slabs gave a mean rate of 18.6 ± 2.8%, sisal mats 18.6 ± 2.0%, papyrus 12.2 ± 1.2% and kakaban 11.8 ± 1.9%. Nylon mats were the last, with a mean rate of 4.0 ± 0.7%. The best performing natural substrates were those with the ability to float and thin fibrous roots that seemed to allow higher aeration of the eggs during incubation. The cost of using natural substrates was minimal.
Resumo:
The success of induced spawning for the production of fish seed depends on many factors which affect hatchery conditions. This paper discusses the results of an investigation on the effects of six different levels of salinity on the fertilization and hatching of Heterobranchus bidorsalis eggs. The results indicate that spermatozoa of H. bidorsalis can survive under a wide range of saline concentrations, with survival increasing with an increase in salinity from 0 to 0.4% and then decreasing as the level of salinity increases. Survival was optimum of 0.4% saline concentration.
Resumo:
This study was an attempt to apply land-based GIS analysis for freshwater aquaculture planning in the Red River Delta of Vietnam. It was based on diverse data sources in order to help decision makers at the site and also to contribute to the modelling of selection processes for aquaculture development planning in the region.
Resumo:
Water currents are vertically structured in many marine systems and as a result, vertical movements by fish larvae and zooplankton affect horizontal transport (Power, 1984). In estuaries, the vertical movements of larvae with tidal periods can result in their retention or ingress (Fortier and Leggett, 1983; Rijnsdorp et al., 1985; Cronin and Forward, 1986; Forward et al., 1999). On the continental shelf, the vertical movements of organisms interact daily and ontogenetically with depth-varying currents to affect horizontal transport (Pillar et al., 1989; Barange and Pillar, 1992; Cowen et al., 1993, 2000; Batchelder et al., 2002).