Hacia la reutilización sustentable de residuos avícolas: evaluación integrada como enmienda orgánica

Poster y resumenLos residuos de la producción avícola (guano de gallinas ponedoras y cama de pollos de engorde) se han utilizado como fertilizantes o enmiendas orgánicas para disminuir el impacto y degradación que causan en los suelos la aplicación de fertilizantes químicos a largo plazo. Sin embargo, pocos estudios han evaluado condiciones de campo contrastantes donde estos residuos se hayan utilizado durante períodos prolongados de tiempo en sistemas de cultivos agrícolas. En este estudio se utilizaron parámetros fisicoquímicos, metabarcoding del gen ARNr 16S e índices de ecotoxicidad para caracterizar el guano de gallinas ponedoras y la cama de pollos de engorde y examinar el efecto de su aplicación en suelos agrícolas durante un período de 10 años (campos sometidos a rotación trigo/soja-maíz, utilizándose tres tratamientos: suelo control sin enmienda añadida, suelo + guano de ponedoras, suelo + cama de pollos). Los residuos avícolas mostraron altas concentraciones de nutrientes (N y P) y una alta conductividad eléctrica, lo que provocó efectos fitotóxicos al evaluar tanto la germinación de semillas como el alargamiento de la radícula de cinco especies vegetales (lechuga: Lactuca sativa variedad "Gallega", rabanito: Raphanus sativus variedad "Puntas blancas", zucchini: Cucurbita maxima variedad "Veronés", rúcula: Eruca sativa y achicoria: Cichorium intybus) en presencia de extractos acuosos de los residuos avícolas. Las comunidades bacterianas presentes en los residuos estuvieron dominadas por miembros típicos del tracto gastrointestinal de las aves, destacando la presencia de familias de bacterias patógenas (Xanthomonadaceae, Clostridiales, Staphylococcaceae, Flavobacteriaceae, Sphingobacteriaceae). Los suelos sometidos a aplicaciones de guano de ponedoras mostraron valores estadísticamente más altos de fósforo total y fósforo extraíble respecto del suelo control, aumentando el riesgo de eutrofización. Por su parte, las comunidades bacterianas de los suelos sometidos a aplicaciones prolongadas de residuos avícolas permanecieron dominadas por familias de bacterias involucradas en los ciclos biogeoquímicos de los nutrientes y en la promoción del crecimiento de las plantas (Gemmatimonadaceae, Sphingomonadaceae, Nitrosomonadaceae, Planctomycetaceae, Nitrospiraceae), destacando la capacidad de resiliencia del suelo. Sin embargo, no debe descartarse la persistencia de bacterias de importancia sanitaria. En conjunto, nuestro trabajo contribuye a comprender los efectos de las prácticas agrícolas locales y, por lo tanto, al apoyo de la adopción de procesos de biotransformación previos a la reutilización de los residuos, de acuerdo con las pautas de sostenibilidad ambiental.Instituto de Microbiología y Zoología Agrícola (IMYZA)Fil: Pin Viso, Natalia Daniela. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Pin Viso, Natalia Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pin Viso, Natalia Daniela. Universidad Nacional de Hurlingham; ArgentinaFil: Rizzo, Pedro Federico. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Microbiología y Zoología Agrícola; ArgentinaFil: Young, Brian Jonathan. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Microbiología y Zoología Agrícola; ArgentinaFil: Gabioud, Emmanuel Adrian. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Paraná; ArgentinaFil: Bres, Patricia Alina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Microbiología y Zoología Agrícola; ArgentinaFil: Riera, Nicolas Iván. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Microbiología y Zoología Agrícola; ArgentinaFil: Merino, Lina. Universidad Nacional de Hurlingham; ArgentinaFil: Farber, Marisa Diana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Agrobiotecnologia y Biologia Molecular; ArgentinaFil: Farber, Marisa Diana. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Farber, Marisa Diana. Universidad Nacional de Hurlingham; Argentin

Aggregate demand, idle time, and unemployment

This paper develops a model of unemployment fluctuations. The model keeps the architecture of the Barro and Grossman [1971] general disequilibrium model but replaces the disequilibrium framework on the labor and product markets by a matching framework. On the product and labor markets, both price and tightness adjust to equalize supply and demand. There is one more variable than equilibrium condition on each market, so we consider various price mechanisms to close the model, from completely flexible to completely rigid. With some price rigidity, aggregate demand influences unemployment through a simple mechanism: higher aggregate demand raises the probability that firms find customers, which reduces idle time for firms’ employees and thus increases labor demand, which in turn reduces unemployment. We use the comparative-statics predictions of the model together with empirical measures of quantities and tightnesses to re-examine the origins of labor market fluctuations. We conclude that (1) price and real wage are not fully flexible because product and labor market tightness fluctuate significantly; (2) fluctuations are mostly caused by labor demand and not labor supply shocks because employment is positively correlated with labor market tightness; and (3) labor demand shocks mostly reflect aggregate demand and not technology shocks because output is positively correlated with product market tightness

Design and Implementation of Degenerate Microsatellite Primers for the Mammalian Clade

Microsatellites are popular genetic markers in molecular ecology, genetic mapping and forensics. Unfortunately, despite recent advances, the isolation of de novo polymorphic microsatellite loci often requires expensive and intensive groundwork. Primers developed for a focal species are commonly tested in a related, non-focal species of interest for the amplification of orthologous polymorphic loci; when successful, this approach significantly reduces cost and time of microsatellite development. However, transferability of polymorphic microsatellite loci decreases rapidly with increasing evolutionary distance, and this approach has shown its limits. Whole genome sequences represent an under-exploited resource to develop cross-species primers for microsatellites. Here we describe a three-step method that combines a novel in silico pipeline that we use to (1) identify conserved microsatellite loci from a multiple genome alignments, (2) design degenerate primer pairs, with (3) a simple PCR protocol used to implement these primers across species. Using this approach we developed a set of primers for the mammalian clade. We found 126,306 human microsatellites conserved in mammalian aligned sequences, and isolated 5,596 loci using criteria based on wide conservation. From a random subset of ∼1000 dinucleotide repeats, we designed degenerate primer pairs for 19 loci, of which five produced polymorphic fragments in up to 18 mammalian species, including the distinctly related marsupials and monotremes, groups that diverged from other mammals 120–160 million years ago. Using our method, many more cross-clade microsatellite loci can be harvested from the currently available genomic data, and this ability is set to improve exponentially as further genomes are sequenced

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe