Muestra de una metodología de investigación en didáctica de las ciencias

El artículo muestra una metodología de investigación que se enmarca dentro de las técnicas de Lingüística Computacional para el Análisis Textual. En general, las técnicas utilizadas para este fin consisten en procedimientos léxicométricos y estudios estadísticos de los resultados obtenidos. La metodología que se muestra en este artículo aplica este instrumento al ámbito de la Didáctica de las Ciencias y, para ello, se hace uso de una aplicación informática (PAFE) con características operativas específicas que lo diferencian de programas similares y que, en síntesis, permite el estudio de conceptos propios de ciencias y sus interrelaciones. En definitiva, el planteamiento metodológico presenta una forma de articular el método estadístico con el marco teórico utilizado en la Didáctica de las Ciencias en general, y en el estudio sobre las concepciones, en particular

Larval habitat discrimination by the African malaria vector Anopheles gambiae sensu lato: Observations from standardized experiments and field studies

Current malaria vector control strategies in Africa target indoor resting and biting mosquitoes and rely heavily on a small number of insecticides. These interventions have lead to the selection of insecticide resistance, behavioural adaptations of the vectors and leave naturally exophilic species nearly untouched. Gravid Anopheles gambiae s.l. female searching for an oviposition site would be a novel target for vector control. However, little is known about the oviposition-site selection behaviour (criteria) of this mosquito. The major aim of the presented research was to investigate if gravid An. gambiae s.l make informed choices when selecting an oviposition site and to identify physical, chemical and biological parameters associated with these choices under standardized experimental and natural field conditions. Standardized field tests and dual-choice oviposition bioassays were used to evaluate responses to soil and rabbit food pellets infusions and habitat water and also to test if bacteria and the volatile chemicals that bacteria produce are relevant to habitat selection. A case–control approach was used to study natural aquatic habitats on Rusinga Island in Lake Victoria during the long rainy season in 2012 to compare the characteristics of habitats colonized (cases) and not colonized (controls) by early instar Anopheles larvae. Factors evaluated included biological characteristics of the sites, zooplankton, invertebrate fauna, physical parameters, nutrients, bacteria communities and volatile chemicals released from the water. Multivariate analyses were used to investigate associations between oviposition site characteristics and habitat selection by Anopheles. The experimental work illustrated that wild and caged An. gambiae s.l. females discriminate between potential aquatic habitats for oviposition and gravid An. gambiae s.l. female select suitable habitats using preferred and avoided chemical cues from water bodies. It furthermore emphasizes that natural infusions can be used to manipulate the oviposition behaviour of An. gambiae s.l.. In the field no evidence was found that bacteria from natural habitat water were involved in habitat selection. Although chemical cues were highly diverse analysis suggests that cases and control habitats differ in the headspace volatile profile of the water. High turbidity >200 nephelometric turbidity units (NTU) was the only environmental factor strongly associated with cases. Other risk factors were higher grass coverage (positive association), and the abundance of creeping water bugs of the family Naucoridae and fish (negative associations). This study demonstrates that gravid An. gambiae females choose suitable habitats for oviposition using a complex system of chemical and visual cues from water bodies. Habitats preferred by An. gambiae exhibited distinct and measurable characteristics that can be potentially exploited to attract and kill gravid females to improve malaria vector monitoring and control

Muestra de una metodología de investigación en didáctica de las ciencias

El artículo muestra una metodología de investigación que se enmarca dentro de las técnicas de Lingüística Computacional para el Análisis Textual. En general, las técnicas utilizadas para este fin consisten en procedimientos léxicométricos y estudios estadísticos de los resultados obtenidos. La metodología que se muestra en este artículo aplica este instrumento al ámbito de la Didáctica de las Ciencias y, para ello, se hace uso de una aplicación informática (PAFE) con características operativas específicas que lo diferencian de programas similares y que, en síntesis, permite el estudio de conceptos propios de ciencias y sus interrelaciones. En definitiva, el planteamiento metodológico presenta una forma de articular el método estadístico con el marco teórico utilizado en la Didáctica de las Ciencias en general, y en el estudio sobre las concepciones, en particular

Analysing chemical attraction of gravid Anopheles gambiae sensu stricto with modified BG-Sentinel traps.

BACKGROUND: Cues that guide gravid Anopheles gambiae sensu lato to oviposition sites can be manipulated to create new strategies for monitoring and controlling malaria vectors. However, progress towards identifying such cues is slow in part due to the lack of appropriate tools for investigating long-range attraction to putative oviposition substrates. This study aimed to develop a relatively easy-to-use bioassay system that can effectively analyse chemical attraction of gravid Anopheles gambiae sensu stricto. METHODS: BG-Sentinel™ mosquito traps that use fans to dispense odourants were modified to contain aqueous substrates. Choice tests with two identical traps set in an 80 m(2) screened semi-field system were used to analyse the catch efficacy of the traps and the effectiveness of the bioassay. A different batch of 200 gravid An. gambiae s.s. was released on every experimental night. Choices tested were (1) distilled versus distilled water (baseline) and (2) distilled water versus soil infusion. Further, comparisons were made of distilled water and soil infusions both containing 150 g/l of Sodium Chloride (NaCl). Sodium Chloride is known to affect the release rate of volatiles from organic substrates. RESULTS: When both traps contained distilled water, 45% (95 confidence interval (CI) 33-57%) of all released mosquitoes were trapped. The proportion increased to 84% (95 CI 73-91%) when traps contained soil infusions. In choice tests, a gravid female was twice as likely to be trapped in the test trap with soil infusion as in the trap with distilled water (odds ratio (OR) 1.8, 95% CI 1.3-2.6). Furthermore, the attraction of gravid females towards the test trap with infusion more than tripled (OR 3.4, 95% CI 2.4-4.8) when salt was added to the substrates. CONCLUSION: Minor modifications of the BG-Sentinel™ mosquito trap turned it into a powerful bioassay tool for evaluating the orientation of gravid mosquitoes to putative oviposition substrates using olfaction. This study describes a useful tool for investigating olfactory attraction of gravid An. gambiae s.s. and provides additional evidence that gravid mosquitoes of this species are attracted to and can be baited with attractive substrates such as organic infusions over a distance of several metres

Factores que inciden en la comprensión lectora

A partir de la reflexión y de la observación, se analiza la necesidad en educación sobre la comprensión lectora; prioridad en esta década. Hoy nadie duda de que haya que enseñar a pensar en la escuela, desde la educación inicial hasta la Universidad

Parámetros hematológicos en polluelos de psitácidos en cautiverio de origen silvestre

El objetivo de este estudio fue describir los parámetros hematológicos en 69 polluelos en cautiverio de origen silvestre, clínicamente sanos, menores de tres meses de edad, en cuatro especies de psitácidos: Pionus senilis (n = 18), Amazona albifrons (n = 15), Amazona autumnalis (n = 25) y Amazona oratrix (n = 11), procedentes de la región central de México. Para determinar dichos parámetros, de cada ejemplar se obtuvieron 500 μl de sangre por punción de la vena braquial. En las cuatro especies citadas, el porcentaje del hematocrito fue de 56,4 ± 3,36; 51 ± 6,52; 47,6 ± 6,47 y 53,8 ± 9,26; el VCM en fl fue de 184,6 ± 13,4; 142,0 ± 25,4; 106,3 ± 11,7 y 162,3 ± 71,9; la cuenta eritrocítica fue de 4,7 ± 2,1 x106/μl; 6,1 ± 8,2 x106/μl; 6,9 ± 1,2 x106/μl y 5,4 ± 1,1 x106/μl; y la cuenta leucocitaria de 3,06 ± 0,15 x103/μl; 3,62 ± 0,24 x103/μl; 4,48 ± 0,36 x103/μl y 3,56 ± 0,71 x103/μl respectivamente para P. senilis, A. albifrons, A. autumnalis y A. oratrix. Se constató tendencia a la heterofilia en A. albifrons y A. oratrix, lo cual puede ser de gran utilidad para un diagnóstico cada vez más preciso en la clínica de aves en cautiverio

Compositional mapping by Z-contrast imaging

This research was sponsored by the Office of Basic Energy Sciences, Materials Sciences and Engineering Division, U.S. Department of Energy (SJP, MV), by the Spanish MCI (projects CONSOLIDER INGENIO 2010 CSD2009-00013 andTEC2008-06756-C03-02/TEC,) and the Junta de Andalucía (PAI research’s groups TEP-120 and TIC-145; project P08-TEP-03516).Peer Reviewe

Adipokines and Inflammation: Focus on Cardiovascular Diseases

It is well established that adipose tissue, apart from its energy storage function, acts as an endocrine organ that produces and secretes a number of bioactive substances, including hormones commonly known as adipokines. Obesity is a major risk factor for the development of cardiovascular diseases, mainly due to a low grade of inflammation and the excessive fat accumulation produced in this state. The adipose tissue dysfunction in obesity leads to an aberrant release of adipokines, some of them with direct cardiovascular and inflammatory regulatory functions. Inflammation is a common link between obesity and cardiovascular diseases, so this review will summarise the role of the main adipokines implicated in the regulation of the inflammatory processes occurring under the scenario of cardiovascular diseases