573 research outputs found
Analytic continuation of residue currents
Let be a complex manifold and f\colon X\to \C^p a holomorphic mapping
defining a complete intersection. We prove that the iterated Mellin transform
of the residue integral associated to has an analytic continuation to a
neighborhood of the origin in \C^p
Berezin Quantization of Gauged WZW and Coset Models
Gauged WZW and coset models are known to be useful to prove holomorphic
factorization of the partition function of WZW and coset models. In this note
we show that these gauged models can be also important to quantize the theory
in the context of the Berezin formalism. For gauged coset models Berezin
quantization procedure also admits a further holomorphic factorization in the
complex structure of the moduli space.Comment: 15+1 pages, no figures, revte
Emergence of communities on a coevolutive model of wealth interchange
We present a model in which we investigate the structure and evolution of a
random network that connects agents capable of exchanging wealth. Economic
interactions between neighbors can occur only if the difference between their
wealth is less than a threshold value that defines the width of the economic
classes. If the interchange of wealth cannot be done, agents are reconnected
with another randomly selected agent, allowing the network to evolve in time.
On each interaction there is a probability of favoring the poorer agent,
simulating the action of the government. We measure the Gini index, having real
world values attached to reality. Besides the network structure showed a very
close connection with the economic dynamic of the system.Comment: 5 pages, 7 figure
A structural and biochemical model of processive chitin synthesis
Chitin synthases (CHS) produce chitin, an essential component of the fungal cell wall. The molecular mechanism of processive chitin synthesis is not understood, limiting the discovery of new inhibitors of this enzyme class. We identified the bacterial glycosyltransferase NodC as an appropriate model system to study the general structure and reaction mechanism of CHS. A high throughput screening-compatible novel assay demonstrates that a known inhibitor of fungal CHS also inhibit NodC. A structural model of NodC, on the basis of the recently published BcsA cellulose synthase structure, enabled probing of the catalytic mechanism by mutagenesis, demonstrating the essential roles of the DD and QXXRW catalytic motifs. The NodC membrane topology was mapped, validating the structural model. Together, these approaches give insight into the CHS structure and mechanism and provide a platform for the discovery of inhibitors for this antifungal target
3D printed scaled setup for smoke transport analysis in a subterranean passenger platform
In this work, the study of smoke fire transportation inside of a subway passenger platform is presented. The study includes a set of numerical simulations to observe the behavior of the smoke inside the platform. Two smoke transport simulations using the FDS program are also included. Subsequently, the development of a 3D - 1:100 scale model is described and it was used to perform an experimental observation of the phenomenon. The model was built by using a 3D printer which allowed to include more architectural details of the real scenario. The inclusion of these details allowed to observe qualitative similarity between the results of the simulation and the experimental work. Although there are clear differences between what could happen in a real scenario and what was observed in the scale model, it was identified that the model is an important complement to the simulations. In addition to the simulations, the use of this type of 3D models allows the observation of the phenomenon by different specialists such as firefighters, policeman, medical personnel, etc., in the same place and its intention is to provide a more interactive tool to the observation group, increasing the time devoted to the development of contingency actions and reducing the costs associated with the logistics of a real simulacrum. The model allows to better identify the strengths, opportunities, weaknesses and threats of the contingency procedures developed by the safety and hygiene groups and to make their corresponding adjustments if necessary.Peer Reviewe
Efecto del ejercicio fÃsico sobre la memoria a corto plazo y velocidad en el procesamiento de información de un paciente que sufrió trauma craneoencefálico: Un caso de estudio
En el artÃculo se presentan los resultados de un estudio mixto, realizado con un paciente adulto de 35 años de edad, diagnosticado con un trauma de cráneo contusión hemorrágica parietal izquierda supercial focal. El propósito de esta investigación fue evidenciar el progreso de un paciente masculino adulto que sufrió un trauma craneoencefálico al realizar ejercicio aeróbico, de contrarresistencia a la vez que realizaba entrenamiento cognitivo, por doce semanas y tres sesiones semanales. Los resultados muestran una mejora en el consumo máximo de oxigeno de un 30%, además a nivel cognitivo el paciente obtuvo mejoras en la velocidad de respuesta, asà como de la respuesta a los comandos del token-test al nalizar las 36 sesiones. Del mismo modo, las respuestas de la entrevista realizada a la esposa ante y después de la intervención muestran una mejora en la memoria a corto plazo, en el procesamiento de la información y en el tiempo de respuesta. En conclusión, se puede apreciar la importancia que tiene las intervenciones de ejercicio fÃsico aunadas al entrenamiento cognitivo, para mejorar el aspecto fÃsico, cognitivo y emocional del paciente que sufre un trauma craneoencefálico, al mismo tiempo que se proporciona una mejora en la calidad de vida de la persona que participa de dicha intervención.
Expresión del receptor de leptina en ovarios de llamas
El receptor a leptina (ObR) se expresa en células de la granulosa, teca interna y células luteales en distintas especies; incluida la alpaca, observándose que su expresión varÃa durante el ciclo estral. En llamas, la disminución en la secreción de leptina produce cuerpos lúteos más pequeños y menor secreción de progesterona, proponiéndose un rol regulador de la leptina sobre la función ovárica. Por lo tanto, el objetivo de este estudio fue evaluar en qué tipo celulares del ovario de llama se expresa el ObR. Se obtuvieron 6 ovarios de llama que fueron fijados en formol bufferado al 4%, realizándose la rutina histológica para confeccionar los tacos. Se realizaron cortes sagitales de 4 μm, y sobre los mismos se realizó la técnica de inmunohistoquÃmica para ObR con el anticuerpo monoclonal primario (sc-8391, Santa Cruz Biotechnology), según lo descripto por Gallelli et al. (2019). El análisis de imágenes subjetivo fue realizado por dos operadores independientes. Se analizaron 10 campos por CL y por cada tipo folicular (primario, secundario y terciario) a 1000x. La población de ObR se evaluó como el promedio del área total inmunopositiva; comparándose entre los distintos tipos foliculares mediante ANOVA (Gallelli et al., 2019). La expresión del ObR se observó en las células luteales y en las células de folÃculos primarios y secundarios y, en el caso de los folÃculos terciarios, se observó su presencia tanto en células de la granulosa como de la teca interna. Dicha expresión no prese ntó diferencias significativas entre los diferentes tipos de folÃculos. En conclusión, el ObR se expresa en los distintos tipos foliculares y en el CL de las llamas, evidenciando el sitio de acción para la leptina. Este conocimiento es de utilidad para avanzar en el estudio de la regulación de la función ovárica mediada por la leptina en esta especie
Teleparallel Version of the Levi-Civita Vacuum Solutions and their Energy Contents
In this paper, we find the teleparallel version of the Levi-Civita metric and
obtain tetrad and the torsion fields. The tensor, vector and the axial-vector
parts of the torsion tensor are evaluated. It is found that the vector part
lies along the radial direction only while the axial-vector vanishes everywhere
because the metric is diagonal. Further, we use the teleparallel version of
Mller, Einstein, Landau-Lifshitz and Bergmann-Thomson prescriptions
to find the energy-momentum distribution of this metric and compare the results
with those already found in General Relativity. It is worth mentioning here
that momentum is constant in both the theories for all the prescriptions. The
energy in teleparallel theory is equal to the corresponding energy in GR only
in Mller prescription for the remaining prescriptions, the energy do
not agree in both theories. We also conclude that Mller's
energy-momentum distribution is independent of the coupling constant
in the teleparallel theory.Comment: 15 pages, accepted for publication in Canadian J. Physic
European and Asian contribution to the genetic diversity of mainland South American chickens
Chickens (Gallus gallus domesticus) from the Americas have long been recognized as descendants of European chickens, transported by early Europeans since the fifteenth century. However, in recent years, a possible pre-Columbian introduction of chickens to South America by Polynesian seafarers has also been suggested. Here, we characterize the mitochondrial control region genetic diversity of modern chicken populations from South America and compare this to a worldwide dataset in order to investigate the potential maternal genetic origin of modern-day chicken populations in South America. The genetic analysis of newly generated chicken mitochondrial control region sequences from South America showed that the majority of chickens from the continent belong to mitochondrial haplogroup E. The rest belongs to haplogroups A, B and C, albeit at very low levels. Haplogroup D, a ubiquitous mitochondrial lineage in Island Southeast Asia and on Pacific Islands is not observed in continental South America. Modern-day mainland South American chickens are, therefore, closely allied with European and Asian chickens. Furthermore, we find high levels of genetic contributions from South Asian chickens to those in Europe and South America. Our findings demonstrate that modern-day genetic diversity of mainland South American chickens appear to have clear European and Asian contributions, and less so from Island Southeast Asia and the Pacific Islands. Furthermore, there is also some indication that South Asia has more genetic contribution to European chickens than any other Asian chicken populations.Michael B. Herrera, Spiridoula Kraitsek, Jose A. Alcalde, Daniel Quiroz .... Vicki Thomson ... Jeremy J. Austin ... et al
Reducing GBA2 activity ameliorates neuropathology in niemann-pick type C mice
The enzyme glucocerebrosidase (GBA) hydrolyses glucosylceramide (GlcCer) in lysosomes. Markedly reduced GBA activity is associated with severe manifestations of Gaucher disease including neurological involvement. Mutations in the GBA gene have recently also been identified as major genetic risk factor for Parkinsonism. Disturbed metabolism of GlcCer may therefore play a role in neuropathology. Besides lysosomal GBA, cells also contain a non-lysosomal glucosylceramidase (GBA2). Given that the two β-glucosidases share substrates, we speculated that over-activity of GBA2 during severe GBA impairment might influence neuropathology. This hypothesis was studied in Niemann-Pick type C (Npc1-/-) mice showing secondary deficiency in GBA in various tissues. Here we report that GBA2 activity is indeed increased in the brain of Npc1-/- mice. We found that GBA2 is particularly abundant in Purkinje cells (PCs), one of the most affected neuronal populations in NPC disease. Inhibiting GBA2 in Npc1-/- mice with a brain-permeable low nanomolar inhibitor significantly improved motor coordination and extended lifespan in the absence of correction in cholesterol and ganglioside abnormalities. This trend was recapitulated, although not to full extent, by introducing a genetic loss of GBA2 in Npc1-/- mice. Our findings point to GBA2 activity as therapeutic target in NPC
- …