Landscape connectivity, habitat structure and activity of bat guilds in farmland-dominated matrices

Agricultural intensification has caused a decline in structural elements in European farmland, where natural habitats are increasingly fragmented. The loss of habitat structures has a detrimental effect on biodiversity and affects bat species that depend on vegetation structures for foraging and commuting. We investigated the impact of connectivity and configuration of structural landscape elements on flight activity, species richness and diversity of insectivorous bats and distinguished three bat guilds according to species-specific bioacoustic characteristics. We tested whether bats with shorter-range echolocation were more sensitive to habitat fragmentation than bats with longer-range echolocation. We expected to find different connectivity thresholds for the three guilds and hypothesized that bats prefer linear over patchy landscape elements. Bat activity was quantified using repeated acoustic monitoring in 225 locations at 15 study plots distributed across the Swiss Central Plateau, where connectivity and the shape of landscape elements were determined by spatial analysis (GIS). Spectrograms of bat calls were assigned to species with the software batit by means of image recognition and statistical classification algorithms. Bat activity was significantly higher around landscape elements compared to open control areas. Short- and long-range echolocating bats were more active in well-connected landscapes, but optimal connectivity levels differed between the guilds. Species richness increased significantly with connectivity, while species diversity did not (Shannon's diversity index). Total bat activity was unaffected by the shape of landscape elements. Synthesis and applications. This study highlights the importance of connectivity in farmland landscapes for bats, with shorter-range echolocating bats being particularly sensitive to habitat fragmentation. More structurally diverse landscape elements are likely to reduce population declines of bats and could improve conditions for other declining species, including birds. Activity was highest around optimal values of connectivity, which must be evaluated for the different guilds and spatially targeted for a region's habitat configuration. In a multi-species approach, we recommend the reintroduction of structural elements to increase habitat heterogeneity should become part of agri-environment schemes.

Thermal release rate studies of nuclear reaction products from polycrystalline metal matrices

The thermal release rate of nuclear reaction products was investigated in offline annealing experiments. This work was motivated by the search for a high melting catcher material for recoiling products from heavy ion induced nuclear fusion reactions. Polycrystalline refractory metal foils of Ni, Y, Zr, Nb, Mo, Hf, W, and Re were investigated as catcher metals. Diffusion data for various tracer/host combinations were deduced from the measured release rates. This work focuses on the diffusion and the release rate of volatile p-elements from row 5 and 6 of the periodic table as lighter homologues of the superheavy elements with Z ≥ 113 to be studied in future experiments. A massive radiation damage enhancement of the diffusion velocity was observed. Diffusion trends have been established along the groups and rows of the periodic table based on the dependence of diffusion velocity on atomic sizes.

Symmetric inverse consistent nonlinear registration driven by mutual information.

A nonlinear viscoelastic image registration algorithm based on the demons paradigm and incorporating inverse consistent constraint (ICC) is implemented. An inverse consistent and symmetric cost function using mutual information (MI) as a similarity measure is employed. The cost function also includes regularization of transformation and inverse consistent error (ICE). The uncertainties in balancing various terms in the cost function are avoided by alternatively minimizing the similarity measure, the regularization of the transformation, and the ICE terms. The diffeomorphism of registration for preventing folding and/or tearing in the deformation is achieved by the composition scheme. The quality of image registration is first demonstrated by constructing brain atlas from 20 adult brains (age range 30-60). It is shown that with this registration technique: (1) the Jacobian determinant is positive for all voxels and (2) the average ICE is around 0.004 voxels with a maximum value below 0.1 voxels. Further, the deformation-based segmentation on Internet Brain Segmentation Repository, a publicly available dataset, has yielded high Dice similarity index (DSI) of 94.7% for the cerebellum and 74.7% for the hippocampus, attesting to the quality of our registration method.

PREDICTION OF DNA METHYLATION BASED ON GENOMIC ARCHITECTURE AND APPLICATIONS OF POSITIONAL WEIGHT MATRICES

Gene silencing due to epigenetic mechanisms shows evidence of significant contributions to cancer development. We hypothesis that the genetic architecture based on retrotransposon elements surrounding the transcription start site, plays an important role in the suppression and promotion of DNA methylation. In our investigation we found a high rate of SINE and LINEs retrotransposon elements near the transcription start site of unmethylated genes when compared to methylated genes. The presence of these elements were positively associated with promoter methylation, contrary to logical expectations, due to the malicious effects of retrotransposon elements which insert themselves randomly into the genome causing possible loss of gene function. In our genome wide analysis of human genes, results suggested that 22% of the genes in cancer were predicted to be methylation-prone; in cancer these genes are generally down-regulated and function in the development process. In summary, our investigation validated our hypothesis and showed that these widespread genomic elements in cancer are highly associated with promoter DNA methylation and may further participate in influencing epigenetic regulation.

Protein cross-linking mediated by tissue transglutaminase correlates with the maturation of extracellular matrices during lung development

At birth, the mammalian lung is still immature. The alveoli are not yet formed and the interairspace walls contain two capillary layers which are separated by an interstitial core. After alveolarization (first 2 postnatal weeks in rats) the alveolar septa mature: their capillary layers merge, the amount of connective tissue decreases, and the mature lung parenchyma is formed (second and third week). During the first 3 wk of life the role of tissue transglutaminase (tTG) was studied in rat lung by immunostaining of cryostat and paraffin sections, by Northern and Western blotting, and by a quantitative determination of gamma-glutamyl-epsilon-lysine. While enzyme activity and intracellular tTG were already present before term, the enzyme product (gamma-glutamyl-epsilon-lysine-crosslink) and extracellular tTG appeared between postnatal days 10 and 19 in the lung parenchyma. In large blood vessels and large airways, which mature earlier than the parenchyma, both the enzyme product and extracellular tTG had already appeared at the end of the first postnatal week. We conclude that tTG is expressed and externalized into the extracellular matrix of lung shortly before maturation of an organ area. Because tTG covalently and irreversibly crosslinks extracellular matrix proteins, we hypothesize that it may prevent or delay further remodeling of basement membranes and may stabilize other extracellular components, such as microfibrils.

Promoting Pollinating Insects in Intensive Agricultural Matrices: Field-Scale Experimental Manipulation of Hay-Meadow Mowing Regimes and Its Effects on Bees

Bees are a key component of biodiversity as they ensure a crucial ecosystem service: pollination. This ecosystem service is nowadays threatened, because bees suffer from agricultural intensification. Yet, bees rarely benefit from the measures established to promote biodiversity in farmland, such as agri-environment schemes (AES). We experimentally tested if the spatio-temporal modification of mowing regimes within extensively managed hay meadows, a widespread AES, can promote bees. We applied a randomized block design, replicated 12 times across the Swiss lowlands, that consisted of three different mowing treatments: 1) first cut not before 15 June (conventional regime for meadows within Swiss AES); 2) first cut not before 15 June, as treatment 1 but with 15% of area left uncut serving as a refuge; 3) first cut not before 15 July. Bees were collected with pan traps, twice during the vegetation season (before and after mowing). Wild bee abundance and species richness significantly increased in meadows where uncut refuges were left, in comparison to meadows without refuges: there was both an immediate (within year) and cumulative (from one year to the following) positive effect of the uncut refuge treatment. An immediate positive effect of delayed mowing was also evidenced in both wild bees and honey bees. Conventional AES could easily accommodate such a simple management prescription that promotes farmland biodiversity and is likely to enhance pollination services.

Pauli Spin Matrices

The Pauli Spin Matrix representation of Spin Operators in Quantum Mechanics are explicitly demonstrated and illustrated in detail for one and two spin systems.

Antropología, violencia y justicia. Repensando matrices de sociabilidad contemporánea en el campo del género y de la familia. En: Avá, nº 18

¿Cómo abordar conceptualmente a la violencia y la justicia en un entramado de relaciones sociales tan complejo como el género y la familia? Esta pregunta recorre el libro compilado por Theophilos Rifiotis y Natalia Castelnuevo. La complejidad de la pregunta se acrecienta al sumar el carácter comparativo a la compilación, ya que la obra pone en diálogo investigaciones de Argentina, Brasil, Colombia y, hasta, Timor Oriental. Una introducción y nueve artículos ordenan este atrayente y estimulante ejercicio comparativo.

Archivos de narrativa y matrices folklóricas : Oralidad, escritura y génesis

Revisito una aproximación al relato folklórico, a partir de un archivo de narrativa folklórica riojana. El enfoque teórico combina aportes de la crítica genética con la teoría informática del hipertexto. El archivo incluye versiones orales reunidas en investigaciones de campo (1985-1999), alrededor de la matriz "La dama fantasma", con elementos del motivo folklórico E 322.3.3.1 "The vanishing hitchhiker". Comprende también recreaciones escriturarias, fílmicas y registros virtuales. El trabajo se encuadra en una investigación sobre "Archivos de Narrativa Tradicional Argentina", que revisa criterios de archivación de narrativa tradicional, de la Encuesta Folklórica de 1921 a 2005

Test de matrices progresivas de Raven: construcción de baremos y constatación del "efecto Flynn"

En este trabajo se presentan los baremos del Test de Matrices Progresivas de Raven, Escala General y Escala Avanzada, Serie II, para la población estudiantil (Tercer ciclo EGB y Polimodal) de la ciudad de La Plata. Se hacen consideraciones sobre el incremento de puntajes (efecto Flynn)que se observa respecto del baremo anterior (1964); sobre las diferencias de las puntuaciones medias según dos grupos etareos (13-16 y 17-18 años) y según modalidad educativa. Los resultados encontrados permiten hacer inferencias respecto de la significación del incremento, especialmente en el caso de las puntuaciones de mayor magnitud en la población que concurre a un tipo especial de establecimiento educativo.

Raven's progressive matrices test: scale construction and verification of "Flynn effect"

In this paper, the scales of Raven's Progressive Matrices Test, General Scale and Advanced Scale, Series II, for the student population (third cycle of EGB and Polimodal ) in the city of La Plata are presented. Considerations are made as regards both the increase in scores (Flynn effect) observed in relation to the previous scale (1964) and the different mean scores according to two age groups (13-16 and 17-18 years of age) and education mode. The findings enabled inferences related to the significance of the increase, particularly in the case of the higher scores in the population attending a special kind of educational institution.

El Conflicto del Campo : Matrices culturales e identificaciones políticas

Este trabajo intenta demostrar cómo el denominado "Conflicto del Campo" (2008) puede ser comprendido a partir de la relación entre la cultura y la política. De esta manera, se parte de los cambios que el sector agropecuario experimentó durante los noventa, para luego exponer cómo durante el Conflicto se posicionaron distintos intereses en un mismo lado. Se mencionan, además, los estudios que otros investigadores realizaron sobre el mismo. La mencionada escena política fue estudiada a partir de la realización de entrevistas en profundidad, con el fin de exponer la relación entre procesos de identificación política y matrices culturales.

Test de matrices progresivas de Raven: construcción de baremos y constatación del "efecto Flynn"

En este trabajo se presentan los baremos del Test de Matrices Progresivas de Raven, Escala General y Escala Avanzada, Serie II, para la población estudiantil (Tercer ciclo EGB y Polimodal) de la ciudad de La Plata. Se hacen consideraciones sobre el incremento de puntajes (efecto Flynn)que se observa respecto del baremo anterior (1964); sobre las diferencias de las puntuaciones medias según dos grupos etareos (13-16 y 17-18 años) y según modalidad educativa. Los resultados encontrados permiten hacer inferencias respecto de la significación del incremento, especialmente en el caso de las puntuaciones de mayor magnitud en la población que concurre a un tipo especial de establecimiento educativo.