Carbono orgánico del suelo bajo sistemas de cultivo contrastantes y su relación con la capacidad de proveer nitrógeno

Los contenidos de carbono (C) orgánico total (COT) y particulado (COP) del suelo disminuyen con los años bajo agricultura y su variación afecta muchos procesos edáficos que determinan la productividad (e.g. la provisión de nitrógeno (N)). Las variaciones de COT y COP son dependientes del balance entre los aportes y la pérdida de C del suelo. Se hipotetiza que en molisoles del Sudeste Bonaerense: i) los cambios en COT y COP en la capa arable, son más dependientes del aporte carbonado de la secuencia de cultivos utilizada que del sistema de labranza (SL) empleado, ii) el contenido de COP es dependiente de las características de los residuos devueltos por el cultivo antecesor inmediato, y iii) las variaciones de COT y COP se relacionan con la capacidad del suelo de proveer N, independientemente del SL y de la secuencia de cultivos. Se determinaron el COT y el COP de muestras tomadas anualmente de 0-5 y 5-20 cm de un ensayo en Balcarce entre 2005 y 2011. El ensayo comprendió dos SL (convencional (LC) y siembra directa (SD)) y tres Secuencias de cultivos (con tres alternativas (Series) cada una), incluyendo maíz (M), trigo (T) y soja (S): MMT, MST y SST. El M y el T fueron fertilizados con N (FN). Hubo disminuciones diferenciales en COT y COP entre SL (sin disminución bajo SD y con disminuciones de 0,34 y 0,39 Mg ha-1 año-1 bajo LC, respectivamente) sólo en la capa de 0-5 cm. En la capa arable completa, aquellas variables disminuyeron con los años de agricultura (0,30 y 0,26 Mg ha-1 año-1, respectivamente), independientemente del SL. No se observó una disminución diferencial de COT ni de COP asociada a las combinaciones de cultivos, independientemente del SL. Tampoco se observó un efecto de las características del cultivo antecesor inmediato sobre el contenido de COP. Asimismo, el COT y el COP presentaron una dinámica similar a la reportada para NAN. No obstante, las relaciones entre NAN y COT y NAN y COP, si bien fueron significativas, presentaron bajos R2 (0,55 y 0,57 (0-5 cm), 0,09 y 0,10 (5-20 cm), 0,18 y 0,17 (0-20 cm), respectivamente). La FN (frecuencia, dosis) puede haber enmascarado los efectos esperados en la relación del COP y COT con el aporte de C por los residuos y, además, de aquéllas con el NAN, por afectar las condiciones de descomposición y transformación de los materiales orgánicos. Las evidencias reunidas no sostuvieron las hipótesis planteadas.Soil total (COT) and particulate (COP) organic carbon (C) contents decrease over the years under cropping. Its variation affects many soil processes that determine soil productivity (e.g. nitrogen (N) supply). COT and COP changes depend on the balance between C input and loss. For mollisols of the southeastern region of Buenos Aires province, it was hypothesized that: 1) COT and COP content decrease in the arable layer and vary as a function of the crop sequence regardless of the tillage system (SL), ii) COP content depends on the immediate preceding crop residue characteristics, and iii) changes in COT and COP are related to the soil N supplying capacity, regardless of the SL and crop sequence. Total organic C and COP were determined in soil samples taken annually at 0-5 cm and 5-20 cm depths in a long-term experiment in Balcarce between 2005 and 2011. The experiment comprised two SL (conventional (LC) and no-till (SD) and three crop sequences (with three alternatives (Series) for each one), including corn (M), wheat (T) and soybean (S): MMT, MST y SST. Corn and T were fertilized with N (FN). There were differential decreases in COT and COP among SL (no decrease under SD and decreases of 0.34 and 0.39 Mg ha-1 yr-1 under LC, respectively) only at the 0-5 cm layer. In the whole arable layer COT and COP decreased over the years under cropping (0.30 and 0.26 Mg ha-1 yr-1, respectively), regardless of the SL. No differential COT nor COP decrease was detected related to crop sequences, regardless of the SL. Neither was there an effect of the immediately preceeding crop residue characteristics on COP content. Likewise, COT and COP showed similar dynamics than reported for NAN. Relationships between NAN and COT and NAN and COP were significant although with low R2 (0.55 and 0.57 (0-5 cm), 0.09 and 0.10 (5-20 cm), 0.18 and 0.17 (0-20 cm), respectively). Frequency and rate of FN may have masked the expected effects of the amount of residue C input on COT and COP and, besides, on the relationship of these two variables and NAN. Nitrogen fertilization affects organic material decomposition and transformation dynamics. The experimentally obtained evidences did not support the posed hypotheses.Fil: Studdert, Guillermo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Domingo, Magalí Noé. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: García, Gisela Vanesa. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Monterubbianesi, María Gloria. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Dominguez, Germán Franco. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentin

Emerging topics in nanophononics and elastic, acoustic, and mechanical metamaterials:An overview

This broad review summarizes recent advances and “hot” research topics in nanophononics and elastic, acoustic, and mechanical metamaterials based on results presented by the authors at the EUROMECH 610 Colloquium held on April 25–27, 2022 in Benicássim, Spain. The key goal of the colloquium was to highlight important developments in these areas, particularly new results that emerged during the last two years. This work thus presents a “snapshot” of the state-of-the-art of different nanophononics- and metamaterial-related topics rather than a historical view on these subjects, in contrast to a conventional review article. The introduction of basic definitions for each topic is followed by an outline of design strategies for the media under consideration, recently developed analysis and implementation techniques, and discussions of current challenges and promising applications. This review, while not comprehensive, will be helpful especially for early-career researchers, among others, as it offers a broad view of the current state-of-the-art and highlights some unique and flourishing research in the mentioned fields, providing insight into multiple exciting research directions

Human papilloma virus genotype diversity of anal infection among trans (male to female transvestites, transsexuals or transgender) sex workers in Argentina

Fil: dos Ramos Farías, María Sol. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología, Parasitología e Inmunología. Centro Nacional de Referencia para el Sida; Argentina.Fil: Picconi, María Alejandra. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Garcia, María Noé. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología, Parasitología e Inmunología. Centro Nacional de Referencia para el Sida; Argentina.Fil: González, Joaquín V. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Basiletti, Jorge. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Pando, María de los Ángeles. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología, Parasitología e Inmunología. Centro Nacional de Referencia para el Sida; Argentina.Fil: Avila, María Mercedes. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Microbiología, Parasitología e Inmunología. Centro Nacional de Referencia para el Sida; Argentina.Background: Reports on the prevalence and genotypes of HPV among trans (male to female transvestites, transsexuals or transgender) sex workers (TSW) are scarce in the literature. Objectives: The aim of the study was to determine the infecting HPV genotypes among TSW in Argentina. Study design: 119 TSW were recruited. Anal cells were self collected with a cytobrush. HPV DNA detection was carried out by PCR and genotyping was performed by RLB. Results: HPV prevalence was 97.4%. 103/111 HPV positive samples were genotyped. High risk genotypes were detected in 82.5%. Two or more coinfecting HPV genotypes were found in 70.9%. One case showed up to 10 different coinfecting types. The number of genotypes was not related to condom usage. Infection rates were similar for HIV positive (100%) and HIV negative (95.8%) participants. However, 18.8% of HIV negative had 4-9 different genotypes, while among HIV positive this percentage raised to 46.2% (p=0.006). Prevalence of high risk genotypes and the frequency of each high risk type were similar between HIV positive and HIV negative groups. According to the participants' answers HIV status showed no association with condom usage. Conclusions: The high HPV prevalence, the coinfection with multiple genotypes and the high frequency of high risk genotypes detected, together with a situation of extreme social marginalization, discrimination and stigmatization make this population to be of extreme vulnerability

Microdureza de la superaleación Nickelvac (N-90) manufacturada por pulvimetalurgia

A través de la técnica de metalurgia de polvos se fabricó la aleación denominada comercialmente como nickelvac (N-90), que se trata de una superaleación hecha principalmente a base de níquel. La aleación fabricada fue sometida primeramente a un proceso de homogenizado a dos temperaturas distintas (1000 y 1065°C durante 2 h) y posteriormente fue envejecida a 350°C durante diferentes tiempos (0.5, 1, 2 y 3 h). De las mediciones de microdureza realizadas en las diferentes muestras, se obtuvo que mayores tiempos de envejecido reflejan mayores valores de dureza. De las observaciones de la microestructura con ayuda de microscopía electrónica de barrido, se pudo determinar la formación de precipitados del tipo Ni xTiy, siendo estos los causantes de los incrementos en la dureza de la aleación, estos precipitados tienen su origen durante el envejecido de la aleación

Eficacia de un sistema virtual multiusuario para la rehabilitación de las habilidades metacognitivas y de cognición social de pacientes con daño cerebral adquirido

Además de los reconocidos problemas que las lesiones cerebrales adquiridas generan en las funciones cognitivas básicas, frecuentemente estos pacientes presentan dificultades de reconocimiento de sus propios déficits (metacognicion) y alteraciones en las relaciones interpersonales (cognición social). Los avances tecnológicos permiten trabajar estos problemas salvando el obstáculo del entorno hospitalario.Navarro Pérez, MD.; Llorens Rodríguez, R.; Garcia Blázquez, MC.; Renau Hernández, O.; Caballero Coulon, MDC.; Mesa Gresa, P.; Alcañiz Raya, ML.... (2012). Eficacia de un sistema virtual multiusuario para la rehabilitación de las habilidades metacognitivas y de cognición social de pacientes con daño cerebral adquirido. Revista de Neurologia. 55(1):50-51. http://hdl.handle.net/10251/79129S505155

NEOTROPICAL CARNIVORES: a data set on carnivore distribution in the Neotropics

Mammalian carnivores are considered a key group in maintaining ecological health and can indicate potential ecological integrity in landscapes where they occur. Carnivores also hold high conservation value and their habitat requirements can guide management and conservation plans. The order Carnivora has 84 species from 8 families in the Neotropical region: Canidae; Felidae; Mephitidae; Mustelidae; Otariidae; Phocidae; Procyonidae; and Ursidae. Herein, we include published and unpublished data on native terrestrial Neotropical carnivores (Canidae; Felidae; Mephitidae; Mustelidae; Procyonidae; and Ursidae). NEOTROPICAL CARNIVORES is a publicly available data set that includes 99,605 data entries from 35,511 unique georeferenced coordinates. Detection/non-detection and quantitative data were obtained from 1818 to 2018 by researchers, governmental agencies, non-governmental organizations, and private consultants. Data were collected using several methods including camera trapping, museum collections, roadkill, line transect, and opportunistic records. Literature (peer-reviewed and grey literature) from Portuguese, Spanish and English were incorporated in this compilation. Most of the data set consists of detection data entries (n = 79,343; 79.7%) but also includes non-detection data (n = 20,262; 20.3%). Of those, 43.3% also include count data (n = 43,151). The information available in NEOTROPICAL CARNIVORES will contribute to macroecological, ecological, and conservation questions in multiple spatio-temporal perspectives. As carnivores play key roles in trophic interactions, a better understanding of their distribution and habitat requirements are essential to establish conservation management plans and safeguard the future ecological health of Neotropical ecosystems. Our data paper, combined with other large-scale data sets, has great potential to clarify species distribution and related ecological processes within the Neotropics. There are no copyright restrictions and no restriction for using data from this data paper, as long as the data paper is cited as the source of the information used. We also request that users inform us of how they intend to use the data

NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics

Xenarthrans—anteaters, sloths, and armadillos—have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, 10 anteaters, and 6 sloths. Our data set includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the southern United States, Mexico, and Caribbean countries at the northern portion of the Neotropics, to the austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n = 5,941), and Cyclopes sp. have the fewest (n = 240). The armadillo species with the most data is Dasypus novemcinctus (n = 11,588), and the fewest data are recorded for Calyptophractus retusus (n = 33). With regard to sloth species, Bradypus variegatus has the most records (n = 962), and Bradypus pygmaeus has the fewest (n = 12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other data sets of Neotropical Series that will become available very soon (i.e., Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans data set. Please cite this data paper when using its data in publications. We also request that researchers and teachers inform us of how they are using these data