Nest Success of Dabbling Ducks in a Human-Mod ified Prairie : Effects of Predation and Habitat Variables at Different Spatial Scales

Nest success of dabbling ducks in the Prairie Pothole region of North America has been declining for the past 40 years in parallel with declines in duck populations. Low nest success seems to result from the combination of an extremely fragmented breeding ground in a human-dominated landscape with an abundant and expanding ii community of generalist nest predators. Studies that examined variables associated with nest vulnerability to predation have produced contradictory results, likely because of simplistic approaches, lack of spatio-temporal replication, use of artificial nests , and the effect of confounding variables. I attempted to clarify the equivocal findings of previous studies by using multiple regression to simultaneously examine the effect of several variables purportedly related to nest predation risk. I collected data on \u3e1,800 dabbling duck nests and associated variables for 16 habitat patches (14 managed for duck production) during two nesting seasons in North Dakota. At the habitat patch level, early and late in each breeding season, I studied the relationship of nest success and upland area, nest density, predator abundance and richness, abundance of alternative prey for predators, and visual and physical obstruction provided by the vegetation . At the spatial scale of the nest and its neighborhood, I examined the likelihood of nest predation in association to nest initiation date, year, distance from nest to a wetland and to an edge, vegetation type at the nest, visual obstruction and heterogeneity of the vegetation around the nest, duck nest species , predator abundance, and presence/absence of 5 carnivorous predators at the nest habitat patch. Nest success was generally low and highly variable in time, and among and within habitat patches. I found no relationship between nest success and any of the variables measured at the patch scale. At the nest level, only initiation date, distance to water, visual obstruction, predator abundance, and duck species had an effect. High variability in the data and the lack of patterns in the relationship of nest predation and the predictor variables precluded me from building a predictive model that explains nest success. Nest success could not be predicted, predation was incidental and risk was high, and there were no safe nest sites for hens to choose in a landscape swamped by nest predators . Nests were located randomly; therefore, there were no clues predators could use to enhance their success in finding nests

Influence of the electric field on the latent heat of the ferroelectric phase transition in KDP

The specific heat, heat flux (DTA trace) and dielectric constant of KDP ferroelectric crystal have been measured simultaneously for various electric fields with a conduction calorimeter. The specific heat presents a strong anomaly but these simultaneous measurements allow us to evaluate the latent heat accurately. Latent heat decreases with field and the value of critical electric field --that where latent heat disappears-- is estimated to be (0.44\pm0.03) kV/cm. Incidentally, we have measured simultaneously the dielectric permittivity which suggests that latent heat is developed as domains are growing.Comment: 7 pages, 6 figures, ReVTeX, twocolumn format, to appear in J. Phys. Cond. Matte

Multicomponent kinematics in a massive filamentary IRDC

To probe the initial conditions for high-mass star and cluster formation, we investigate the properties of dense filaments within the infrared dark cloud G035.39-00.33 (IRDC G035.39) in a combined Very Large Array (VLA) and the Green Bank Telescope (GBT) mosaic tracing the NH3 (1,1) and (2,2) emission down to 0.08 pc scales. Using agglomerative hierarchical clustering on multiple line-of-sight velocity component fitting results, we identify seven extended velocity-coherent components in our data, likely representing spatially coherent physical structures, some exhibiting complex gas motions. The velocity gradient magnitude distribution peaks at its mode of 0.35 km/s/pc and has a long tail extending into higher values of 1.5 - 2 km/s/pc, and is generally consistent with those found toward the same cloud in other molecular tracers and with the values found towards nearby low-mass dense cloud cores at the same scales. Contrary to observational and theoretical expectations, we find the non-thermal ammonia line widths to be systematically narrower (by about 20%) than those of N2H+ (1-0) line transition observed with similar resolution. If the observed ordered velocity gradients represent the core envelope solid-body rotation, we estimate the specific angular momentum to be about 2 x 10^21 cm^2/s, similar to the low-mass star-forming cores. Together with the previous finding of subsonic motions in G035.39, our results demonstrate high levels of similarity between kinematics of a high-mass star-forming IRDC and the low-mass star formation regime.Comment: 22 pages, 14 figures, accepted to Ap

Subnational Fiscal Rules: Empirical Review, International Experiences and Their Challenges in the New Post-COVID Fiscal Institutionality

Durante las últimas dos décadas, la utilización de reglas fiscales ha tenido un aumento significativo alrededor del mundo. Si bien la evidencia internacional ha destacado algunos beneficios a partir de su implementación, las experiencias de América Latina en la puesta en marcha y los resultados han sido heterogéneos. Esas reglas fiscales inicialmente cobijaban a los gobiernos nacionales, pero luego se fueron ampliando a los subnacionales, en parte porque los procesos de descentralización fiscal fueron entregando más responsabilidades en materia de ingreso y gasto público a los gobiernos subnacionales. La revisión de las experiencias internacionales en esta materia provee lecciones de política importantes para futuros cambios en las normas de responsabilidad fiscal nacional y subnacional en los países, en especial ante las condiciones que ha impuesto al sector público la pandemia del COVID-19. Este documento hace una revisión exhaustiva de la evolución de las reglas fiscales subnacionales alrededor del mundo, identificando los principales factores que contribuyen al éxito o fracaso de estas. Además, permite identificar los elementos clave en una posible agenda de reforma ante las fallas en las reglas fiscales que ha visibilizado la actual pandemia.During the last two decades, the use of fiscal rules has increased significantly around the world. Although international evidence has highlighted some benefits from its implementation, the experiences of Latin America in the implementation and the results have been heterogeneous. These fiscal rules initially covered the national governments but were later extended to subnational governments, in part because the fiscal decentralization processes were handing more responsibilities in terms of revenue and public spending to subnational governments. The review of international experiences in this area provides important policy lessons for future reforms in national and subnational fiscal responsibility regulations, especially given the conditions imposed on the public sector by the COVID-19 pandemic. This document makes an extensive review of the evolution of subnational fiscal rules worldwide, identifying the main factors that contribute to their success or failure. In addition, it allows identifying the key elements in a possible reform agenda to face the flaws in the fiscal rules that the current pandemic has made visible.Reglas fiscales subnacionales: Revisión empírica, experiencias internacionales y sus desafíos en la nueva institucionalidad fiscal post COVID Enfoque Desde la década del noventa, distintos gobiernos alrededor del mundo iniciaron la implementación de reglas fiscales que establecen límites a distintas variables como el gasto corriente o el endeudamiento, con el fin de lograr la estabilidad macroeconómica del país en el mediano plazo. Inicialmente las reglas cobijaban únicamente a los gobiernos nacionales, pero luego se fueron extendiendo a los gobiernos subnacionales. Durante el periodo analizado se han experimentado distintos choques económicos que han servido de experimento natural acerca del funcionamiento y conveniencia de las distintas reglas fiscales que han originado ajustes en su diseño. Este documento analiza la experiencia internacional teórica y empírica con las reglas fiscales subnacionales con el propósito de extraer lecciones de política para Colombia y en especial en un escenario pospandemia. Contribución En países altamente descentralizados como Colombia, la discusión sobre reglas fiscales y sus impactos cobra una importancia mayor, dadas las tensiones que se generan entre las relaciones fiscales intergubernamentales, las presiones por financiar políticas públicas en distintas esferas del gobierno, y la diferente institucionalidad, capacidad y autonomía fiscal con la que los distintos niveles cuentan para responder a las demandas locales. Con base en la revisión de la literatura teórica y empírica sobre reglas fiscales subnacionales, y en el marco de la experiencia internacional en la materia, este trabajo contribuye con la recopilación y la extracción de lecciones útiles para el caso de Colombia. Resultados El diseño de reglas fiscales se relaciona con la estructura institucional y las principales características de su desempeño macro fiscal. La organización institucional, su grado de desarrollo relativo, las asimetrías verticales existentes, el tipo de ingreso que recaudan los gobiernos subnacionales (por ejemplo, qué tanto generan recursos propios o cuánto de los ingresos proviene de la explotación de recursos naturales) y la composición del gasto de estos (tanto en su clasificación económica como funcional), son elementos centrales para tener en cuenta en el diseño y seguimiento de los componentes de la institucionalidad fiscal intergubernamental y su relación con la regla fiscal vigente. A su vez, estas características les dan forma a las reglas fiscales y sugieren qué indicador de monitoreo se debe priorizar, ya sea gasto, déficit o deuda. Por supuesto, que tener en cuenta estas particularidades complejiza su diseño y cuestiona las reglas fiscales de primera generación. Frase destacada: “Este documento analiza la experiencia internacional teórica y empírica con las reglas fiscales subnacionales con el propósito de extraer lecciones de política para Colombia y en especial en un escenario pospandemia”

Effect of Partial Replacement of Steam Rolled Corn With Soybean Hulls or Prickly Pear Cactus in the Horse’s Diet in the Presence of Live Saccharomyces cerevisiae on In Vitro Fecal Gas Production

Grains represent important sources of energy to horses. Feeding diets with high-grain contents is associated withsome feeding disorders and less feed utilization [1] due tomicrobial profile disturbance [2] and impaired fibrolytic activity in the hindgut [3]. Therefore, partial replacement of grains (energy sources) with other feeds, rich in fibers, would appear to be a good alternative solution to prevent such problems and increase feed utilization and reduce feeding costs.The aim of the study was to evaluate the fecal fermentation of partial replacing steam rolled corn with soybean hulls (SH) or prickly pear cactus (PC) as energy source in horse diets, in the presence of Saccharomyces cerevisiae. Steam rolled corn was replaced with SH at 0% (control), 7.5% (SH75), and 15% (SH150) in the first trial, whereas it was replaced with PC at 0% (control; the same of the first trial), 7.5% (PC75), and 15% (PC150) in the second trial. Yeast of S. cerevisiae was added at 0, 2, and 4 mg/g dry matter (DM) of incubated substrates. Fecal inoculum was obtained from four adult English Thoroughbred horses fed on an amount of commercial concentrate and oat hay ad libitum. Interactions observed between PC rations and yeast doses for the asymptotic gas production (GP), the rate of GP and carbon dioxide (CO2) production during some incubation hours. Moreover, with no effect due to SH rations (P > .05), increased (P < .05) rate of GP was observed with the ration PC75 compared with other rations. Besides, PC75 and PC150 rations with 0 mg yeast/g DM linearly decreased (P < .05) CO2 production at some incubation hours. However, SH75 and SH150 ration had increased (P ¼ .005) DM degradability (DMD). Yeast addition at 2 mg/g DM increased the asymptotic GP (P ¼ .048) with the SH75 and PC150 rations. The level of 4 mg yeast/g DM increased the asymptotic GP (P ¼.048) from the SH150 ration. Yeast addition at 2 and 4 mg/g DM increased (P < .05) the asymptotic GP from PC75 and PC150 rations, respectively, with increasing DMD with the both doses. Yeast addition increased (P <.05) CO2 production from SH75, SH150, PC75, and PC150 rations. It could be concluded that SH and PC can replace steam rolled corn at levels of 7.5% to 15% without negative effect of fermentation kinetics and with better fermentation performance in the presence of yeast at 2 mg/g DM of substrates

Reconstruction of Past Environment and Climate Using Wetland Sediment Records from the Sierra Nevada

Understanding the effects of climate change and human activities on fragile mountain ecosystems is necessary to successfully managing these environments under future climate scenarios (e.g., global warming, enhanced aridity). This can be done through the study of paleoecological records, which can provide long paleoenvironmental databases containing information on how ecosystems reacted to climate change and human disturbances before the historical record. These studies can be particularly interesting when focusing on especially warm and/or dry past climatic phases. Biotic (pollen, charcoal) and abiotic (physical, geochemistry) analyses from wetland sediment records from the Sierra Nevada, southern Spain record changes in vegetation, fire history and lake sedimentation since ~11,700 years (cal yr BP). This multiproxy paleoecological study indicates that maxima in temperature and humidity occurred in the area in the Early and Middle Holocene, with a peak in precipitation between ~10,500 and 7000 cal yr BP. This is deduced by maxima in water runoff, the highest abundance of tree species and algae and high total organic carbon values recorded in the alpine wetland’s sedimentary records of the Sierra Nevada during that time period. In the last 7000 cal yr BP, and especially after a transition period between ~7000 and 5000 cal yr BP, a progressive aridification process took place, indicated by the decrease in tree species and the increase in xerophytic herbs in this region and a reduction in water runoff evidenced by the decrease in detritic input in the wetland sedimentary records. An increasing trend in Saharan dust deposition in the Sierra Nevada wetlands is also recorded through inorganic geochemical proxies, probably due to a coetaneous loss of vegetation cover in North Africa. The process of progressive aridification during the Middle and Late Holocene was interrupted by millennial-scale climatic oscillations and several periods of relative humid/droughty conditions and warm/cold periods have been identified in different temperature and/or precipitation proxies. Enhanced human impact has been observed in the Sierra Nevada in the last ~3000 cal yr BP through the increase in fires, grazing, cultivation, atmospheric pollution as well as reforestation by Pinus and the massive cultivation of Olea at lower altitudes.This study was supported by projects CGL2013-47038-R and CGL2017-85415-R funded by Ministerio de Economía y Competitividad of Spain and Fondo Europeo de Desarrollo Regional FEDER; Séneca Project 20788/PI/18; Junta de Andalucía I+D+i Junta de Andalucía 2020 Retos P-20-00059, FEDER Project B-RNM-144-UGR18, UGR-FEDER B-RNM-144-UGR18 Proyectos I + D + i del Programa Operativo FEDER 2018 and the research group RNM-190 (Junta de Andalucía). M.J.R.R. acknowledges the postdoctoral funding provided by the European Commission/H2020 (ERC-2017-ADG, project number 788616). J.C. acknowledges the postdoctoral funding provided by the Academy of Finland (project number 316702). A.G.-A. acknowledges the Ramón y Cajal fellowship RYC-2015-18966 provided by the Ministerio de Economía y Competitividad of the Spanish Government. M.R.G. acknowledges funding by the Juan de la Cierva-Incorporación program in the University of Granada (IJCI-2017-33755) from Secretaría de Estado de I+D+i, Spain. RSA acknowledges several travel grants from Northern Arizona University to support this work

Investigación en sistemas de trading, una propuesta para mejorar el desempeño de las AFOREs en México

El principal objetivo de un sistema de trading es maximizar sus beneficios utilizando señales y confirmaciones de tendencia que ayuden a mejorar el porcentaje de entradas y salidas apropiadas. En este proyecto, la fuente de estas señales proviene de un modelo de inteligencia artificial, específicamente una red neuronal multicapa. El entrenamiento del modelo utiliza datos diarios de contratos futuros continuos. Para mejorar el desempeño del sistema se tomó en cuenta un criterio de selección e importancia de variables con base a la estadística, así como una optimización de los hiper parámetros del modelo. Con el fin de disminuir la minusvalía de las posiciones abiertas, se propuso la implementación de una cobertura dinámica. Dicha cobertura se ejecutó con opciones para preservar el capital y gestionar el riesgo. El impacto de esta investigación se dirigió a contribuir e innovar el proceso de estrategias de inversión que realizan actualmente los fondos de pensión (AFORES) en México. Siendo el rendimiento un factor determinante para el retiro de futuras generaciones, y tomando en cuenta el contexto actual y recientes reformas en la materia, las estrategias de inversión apoyadas en tecnología se ha convertido en un área de suma importancia para nuestra sociedad.ITESO, A.C

Latitude does not influence cavity entrance orientation of South American avian excavators

In the Northern Hemisphere, several avian cavity excavators (e.g., woodpeckers) orient their cavities increasingly toward the equator as latitude increases (i.e., farther north), and it is proposed that they do so to take advantage of incident solar radiation at their nests. If latitude is a key driver of cavity orientations globally, this pattern should extend to the Southern Hemisphere. Here, we test the prediction that cavities are oriented increasingly northward at higher (i.e., colder) latitudes in the Southern Hemisphere and describe the preferred entrance direction(s) of 1501 cavities excavated by 25 avian species (n = 22 Picidae, 2 Trogonidae, 1 Furnariidae) across 12 terrestrial ecoregions (15°S ? 55°S) in South America. We used Bayesian projected normal mixed-effects models for circular data to examine the influence of latitude, and potential confounding factors, on cavity orientation. Also, a probability model selection procedure was used to simultaneously examine multiple orientation hypotheses in each ecoregion, to explore underlying cavity-orientation patterns. Contrary to predictions, and patterns from the Northern Hemisphere, birds did not orient their cavities more toward the equator with increasing latitude, suggesting that latitude may not be an important underlying selective force shaping excavation behavior in South America. Moreover, unimodal cavity-entrance orientations were not frequent among the ecoregions analyzed (infour ecoregions), whereas bimodal (in five ecoregions) or uniform (in three ecoregions) werealso common, although many of these patterns were not very sharp. Our results highlight the need to include data from under-studied biotas and regions to improve inferences at macroecology scales. Furthermore, we suggest a re-analysis of Northern Hemisphere cavity orientation patterns using a multimodel approach, and a more comprehensive assessment of the role of environmental factors as drivers of cavity orientation at different spatial scales in both hemispheres.Fil: Ojeda, Valeria Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Schaaf, Alejandro Alberto. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Altamirano, Tatiana Edith. University of British Columbia; CanadáFil: Bonaparte, Eugenia Bianca. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Bragagnolo, Laura Araceli. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Chazarreta, L.. Secretaría de Ambiente y Desarrallo Sustentable de la Nación; ArgentinaFil: Cockle, Kristina Louise. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Dias, R.. Universidade do Brasília; BrasilFil: Di Sallo, Facundo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Ibarra, T.. Pontificia Universidad Católica de Chile; ChileFil: Ippi, Silvina Graciela. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jauregui, Adrian. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Área Zoología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jimenez, Jaime E.. Universidad de Magallanes; ChileFil: Lammertink, J. Martjan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Lopez, F.. Universidad Nacional de La Pampa; ArgentinaFil: Nuñez Montellano, Maria Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; ArgentinaFil: de la Peña, Martín. No especifíca;Fil: Rivera, Luis Osvaldo. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Vivanco, Constanza Guadalupe. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Santillán, Miguel. Museo de Historia Natural de La Pampa; ArgentinaFil: Soto, G.. Cornell University; Estados UnidosFil: Vergara, P.. Universidad de Santiago de Chile; ChileFil: Politi, Natalia. University of North Texas; Estados Unido