Evolución del perfil socioacadémico de la física en estudiantes venezolanos

This work presents a comparative and descriptive analisys of the socio-academic profile shown by students of physics in Venezuela, and the relationship between this profile and variables as: educational level, gender, academic performance in physics, and general attitude towards science. Our results, from a 825 High School sample, reveals a decrease in the socio-academic profile of subject and attitude along the school year. However, no decrease was found between a given school level and the next. The subject profile obtained from male student scores was always higher than the corresponding one obtained from female student scores. Their evolutions were similar, with an increase in the gap between the two as the educational level increased

Relacions sexuals i rendiment físic: aclarint el mite de l’efecte perjudicial de mantenir relacions sexuals coitals abans de participar en activitats físiques extenuants

La nostra revisió bibliogràfica pretén presentar l’evidència científica que contradiu el mite que mantenir relacions sexuals coitals abans de realitzar alguna activitat que requereix un rendiment físic màxim és perjudicial. Encara que, en l’actualitat, aquest mite es continua difonent en alguns ambients esportius, no existeixen estudis que indiquin que mantenir relacions sexuals coitals sigui perjudicial. Prenent com a base mesuraments de paràmetres fisiològics, metabòlics i psicològics, s’ha arribat a determinar que el coit no afecta negativament ni positivament el rendiment físic. L’escassa evidència científica fa que aquest tema prengui importància i se suggereix que es realitzin més investigacions per tal d’oferir consells i educació apropiada a les poblacions físicament actives de diverses edats, com és el cas dels esportistes

Long-term assessment of surface water quality in a highly managed estuary basin

Anthropogenic developments in coastal watersheds cause significant ecological changes to estuaries. Since estuaries respond to inputs on relatively long time scales, robust analyses of long-term data should be employed to account for seasonality, internal cycling, and climatological cycles. This study characterizes the water quality of a highly managed coastal basin, the St. Lucie Estuary Basin, FL, USA, from 1999 to 2019 to detect spatiotemporal differences in the estuary’s water quality and its tributaries. The estuary is artificially connected to Lake Okeechobee, so it receives fresh water from an external basin. Monthly water samples collected from November 1999 to October 2019 were assessed using principal component analysis, correlation analysis, and the Seasonal Kendall trend test. Nitrogen, phosphorus, color, total suspended solids, and turbidity concentrations varied sea-sonally and spatially. Inflows from Lake Okeechobee were characterized by high turbidity, while higher phosphorus concentrations characterized inflows from tributaries within the basin. Differences among tributaries within the basin may be attributed to flow regimes (e.g., significant releases vs. steady flow) and land use (e.g., pasture vs. row crops). Decreasing trends for orthophosphate, total phosphorus, and color and increasing trends for dissolved oxygen were found over the long term. Decreases in nutrient concentrations over time could be due to local mitigation efforts. Understanding the differences in water quality between the tributaries of the St. Lucie Estuary is es-sential for the overall water quality management of the estuary

Epoca crítica de competencia y control químico de malezas en cebolla de bulbo (Allium cepa L.).

Se determinó el efecto de las malezas sobre el rendimiento de este cultivo y el método de control integrado más eficaz para combatirlas. Los ensayos se localizaron en el Centro de Investigaciones Tibaitatá, con el híbrido Granex Amarillo. Para determinar la época crítica de competencia de malezas, se efectuaron desyerbas a los 20 días de la siembra y de ahí en adelante cada 10 días. Por otra parte, se realizó otro ensayo para evaluar la efectividad de varios herbicidas y un tercer ensayo en la zona cebollera del Norte de Santander, para evaluar el efecto del carbón activado en la absorción del herbicida. Se obtuvo como época crítica de competencia el lapso comprendido entre 30 y 40 días contados a partir de la germinación del cultivo. Se logró conocer que en esas condiciones y en cebolla de siembra directa, se deben efectuar 4 desyerbas: a los 10, 40, 80 y 100 días a partir de la emergencia del cultivo, bajo condiciones de la sabana de Bogotá. Los mejores productos en cuanto a selectividad al cultivo y buen control de malezas fueron: metabenziazuron (2 y 3 kg/ha), oxadiazone (1 kg/ha) y metazole (1 y 2 kg/ha). El tratamiento con carbón activado es efectivo para lograr selectividad herbicida, pues se observó que el alicep, que había sido tóxico, ofrecía control aceptable de malezas, sin causar daño al cultivoCebolla de bulbo-Cebolla japonesaMaestría en CienciasMaestrí

The Zero-Removing Property and Lagrange-Type Interpolation Series

The classical Kramer sampling theorem, which provides a method for obtaining orthogonal sampling formulas, can be formulated in a more general nonorthogonal setting. In this setting, a challenging problem is to characterize the situations when the obtained nonorthogonal sampling formulas can be expressed as Lagrange-type interpolation series. In this article a necessary and sufficient condition is given in terms of the zero removing property. Roughly speaking, this property concerns the stability of the sampled functions on removing a finite number of their zeros

Molecular gas in super spiral galaxies

We thank the referee for the careful revision of the manuscript and constructive comments. UL acknowledges support by the research projects AYA2017-84897-P and PID2020-114414GB-I00 from the Spanish Ministerio de Economía y Competitividad, from the European Regional Development Funds (FEDER) and the Junta de Andalucía (Spain) grants FQM108. This work is based on observations carried out under project numbers 205-19 and 068-20 with the IRAM 30m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). This research made use of the “K-corrections calculator” service available at http://kcor.sai.msu.ru/ . This research made use of Astropy, a community- developed core Python ( http://www.python.org ) package for Astronomy (Astropy Collaboration 2013, 2018); ipython (Pérez & Granger 2007); matplotlib (Hunter 2007); SciPy, a collection of open source software for scientific computing in Python (Virtanen et al. 2020); and NumPy, a structure for efficient numerical computation (van der Walt et al. 2011). This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. This work was made possible by the NASA/IPAC Extragalactic Database and the NASA/ IPAC Infrared Science Archive, which are both operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. We acknowledge the usage of the HyperLeda database ( http://leda.univ-lyon1.fr ).At the highest stellar masses (log(M*) ≳ 11.5 M⊙), only a small fraction of galaxies are disk-like and actively star-forming objects. These so-called ‘super spirals’ are ideal objects to better understand how galaxy evolution proceeds and to extend our knowledge about the relation between stars and gas to a higher stellar mass regime. We present new CO(1–0) data for a sample of 46 super spirals and for 18 slightly lower-mass (log(M*) > 11.0 M⊙) galaxies with broad HI lines – HI fast-rotators (HI-FRs). We analyze their molecular gas mass, derived from CO(1–0), in relation to their star formation rate (SFR) and stellar mass, and compare the results to values and scaling relations derived from lower-mass galaxies. We confirm that super spirals follow the same star-forming main sequence (SFMS) as lower-mass galaxies. We find that they possess abundant molecular gas (mean redshift-corrected molecular gas mass fraction (log(fmol, zcorr) = −1.36 ± 0.02), which lies above the extrapolation of the scaling relation with stellar mass derived from lower-mass galaxies, but within the relation between fmol and the distance to the SFMS. The molecular gas depletion time, τdep = Mmol/SFR, is higher than for lower-mass galaxies on the SFMS (τdep = 9.30 ± 0.03, compared to τdep = 9.00 ± 0.02 for the comparison sample) and seems to continue an increasing trend with stellar mass. HI-FR galaxies have an atomic-to-molecular gas mass ratio that is in agreement with that of lower-mass galaxies, indicating that the conversion from the atomic to molecular gas proceeds in a similar way. We conclude that the availability of molecular gas is a crucial factor to enable star formation to continue and that, if gas is present, quenching is not a necessary destiny for high-mass galaxies. The difference in gas depletion time suggests that the properties of the molecular gas at high stellar masses are less favorable for star formation.Spanish Ministerio de Economía y Competitividad AYA2017-84897-P, PID2020-114414GB-I00European Regional Development Funds (FEDER) AYA2017-84897-P, PID2020-114414GB-I00Junta de Andalucía (Spain) FQM108INSU/CNRS (France) 205-19, 068-20MPG (Germany) 205-19, 068-20IGN (Spain) 205-19, 068-20IPACNational Aeronautics and Space Administration NASACentre National de la Recherche Scientifique CNR

A Framework for Participatory Impact Assessment: involving stakeholders in European policy making, a case study of land use change in Malta

A Framework for Participatory Impact Assessment is presented for use within European land use policy impact assessment. The context and rationale for the development of the Framework are outlined, both in the context of European policy making and within a project called "Sustainability Impact Assessment: Tools for Environmental, Social and Economic Effects of Multifunctional Land Use in European Regions". A detailed description of the sequence of methods that make up the Framework is provided, followed by illustrations and details of the practical application and results from a case study in Malta, where the Framework was used to carry out an impact assessment of biodiversity policies. After reporting on the reflections of the research team and valuable feedback provided by Maltese stakeholders, the Framework’s ability to enhance the quality, credibility and legitimacy of European policy impact assessment is discusse