2,833 research outputs found
Long exposure point spread function estimation from solar adaptive optics loop data
Adaptive optics (AG) systems provide partial correction to wavefront distortions introduced by the Earth\u27s atmosphere. They have become an essential tool to obtain diffraction-limited observations from ground-based telescopes. However, the AG correction is only partial and post-processing with a good estimate of the point spread function (PSF) is required.
PSF estimates are impossible to measure directly during solar observations due to the lack of point sources in the field-of-view. Moreover, the highly variable day-time seeing conditions require the estimated PSF to be simultaneous with the captured image. A method is presented to estimate the long-exposure PSF of AG-corrected solar observations using the AG control loop data. The wavefront sensor and the deformable mirror data produced by the AG system during normal operation provide enough information to estimate the long-exposure PSE. Using this method, each individual AG-corrected image can be deconvolved with its own estimated PSF.
An attempt was made to verify the accuracy of the method by observing the star Sirius. The AG system successfully produced AG-corrected star images, which provide direct PSF measurements that can be compared to the estimated PSF. However, the poor performance of the AG system under low light levels, for which it was not designed, led to large uncertainties in the estimated PSFs.
The PSF estimation method was tested on real solar observations, where an estimation of the AG-corrected PSF is normally difficult. The observations were deconvolved with the estimated PSFs, producing significantly improved quantitative measurements and scientific data. A measurement of the performance of the solar AG during different seeing conditions was obtained for the first time from these observations
Remarks on twisted theories with matter
We investigate some aspects of N=2 twisted theories with matter
hypermultiplets in the fundamental representation of the gauge group. A
consistent formulation of these theories on a general four-manifold requires
turning on a particular magnetic flux, which we write down explicitly in the
case of SU(2k). We obtain the blowup formula and show that the blowup function
is given by a hyperelliptic sigma-function with singular characteristic. We
compute the contact terms and find, as a corollary, interesting identities
between hyperelliptic Theta functions.Comment: 18 pages, harvmac, one figur
Allorecognition by T Lymphocytes and Allograft Rejection
Recognition of donor antigens by recipient T cells in secondary lymphoid organs initiates the adaptive inflammatory immune response leading to the rejection of allogeneic transplants. Allospecific T cells become activated through interaction of their T cell receptors with intact allogeneic MHC molecules on donor cells (direct pathway) and/or donor peptides presented by self-MHC molecules on recipient antigen presenting cells (APCs) (indirect pathway). In addition, recent studies show that alloreactive T cells can be also stimulated through recognition of allogeneic MHC molecules displayed on recipient APCs (MHC cross-dressing) after their transfer via cell-cell contact or through microvesicles (semi-direct pathway). The specific allorecognition pathway used by T cells is dictated by intrinsic and extrinsic factors to the allograft and can influence the nature and magnitude of the alloresponse and rejection process. Consequently, various organs and tissues such as skin, cornea and solid organ transplants are recognized differently by pro-inflammatory T cells through these distinct pathways, which may explain why these grafts are rejected in a different fashion. On the other hand, the mechanisms by which anti-inflammatory regulatory T cells (Tregs) recognize alloantigen and promote transplantation tolerance are still unclear. It is likely that thymic Tregs are activated through indirect allorecognition while peripheral Tregs recognize alloantigens in a direct fashion. As we gain insights into the mechanisms underlying allorecognition by pro-inflammatory and regulatory T cells, novel strategies are being designed to prevent allograft rejection in the absence of ongoing immunosuppressive drug treatment in patients
Mortalidad materna en México
contiene cuadros e imágenesLa organización del presente trabajo de investigación se conformo en el capÃtulo 1
la mortalidad materna, en el capÃtulo 2 integra las principales complicaciones de la
muerte materna en nuestro paÃs, el capÃtulo 3 se compone de la Legislación en materia de salud como: Norma Oficial Mexicana PROY-NOM-007-SSA2-2010, Para la atención de la mujer durante el embarazo, parto y puerperio, y del recién nacido, Ley General de Salud y artÃculo 3° constitucional y otros Programas como Arranque Parejo en la Vida, Embarazo Saludable y el actual. Por último en el
CapÃtulo 4 integra las intervenciones de EnfermerÃa antes del embarazo y durante
embarazo para la atención del embarazo sano o complicado, para implementar la atención de la urgencia y complicación obstétrica para ir contemplando la reducción del objetivo del milenio
Synthesis of the (1→6)-linked thiodisaccharide of galactofuranose. Inhibitory activity against a β-galactofuranosidase
Methyl (methyl alpha,beta-D-galactofuranosid)uronate was employed as the starting compound,which was per-O-silylated with TBSCl and reduced with LiAlH4 to afford methyl 2,3,5-tri-O-tert-butyldimethylsilyl-b-D-galactofuranoside (2b) as akey precursor for the preparation of methyl per-O-tert-butyldimethylsilyl-6-thio-b-D-galactofuranos ide (12). The free thiol group of 12 was glycosylated and the product O-deprotected to afford the target b-D-Galf-S-(1,6)-b-D-Galf-OMe (14). The conformations of this thiodisaccharide were preliminarily studied using combined theoretical calculatio ns and NMR data.Further-more, the glycomimetic 14 showed to be a competitiv einhibitor of the beta-galactofuranosidase from Penicillum fellutanum (Ki = 3.62 mM).Fil: Repetto, Evangelina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Marino, MarÃa Carla. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Varela, Oscar Jose. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono; Argentin
Evaluation of pesticide pollution in the Gualeguay Basin: An extensive agriculture area in Argentina
The current agricultural production model was established in the 1990s based on the use of genetically modified organisms and agrochemicals, mainly pesticides. Despite pesticide spread and prevalence, data on the associated concentrations in surface watercourses are comparatively scarce. The aim of this work was to evaluate to what extent the >20 years of agricultural activity with the use of pesticides has impacted on the Gualeguay-River basin, with respect to the different stream orders: the tributary streams and main channel. Thirteen sites within the lower Gualeguay basin were sampled once every season (autumn, winter, spring, and summer) in 2017–2018. The samples were analyzed by gas chromatography time-of-flight mass-spectrometry (GC-TOF-MS) and ultraperformance liquid chromatography tandem mass-spectrometry (UPLC-MS/MS). The most frequently detected pesticide was glyphosate along with its metabolite (aminomethyl)phosphonic acid (AMPA), at 82 % and 71 % of surface water samples and 97 % and 92 % of bottom sediments, respectively; followed by atrazine in 73 % of the water samples. The concentrations of these compounds, each in their respective matrices, did not present sufficient statistically significant differences for differentiating a tributary stream from the main channel. Regardless of glyphosate's affinity for the suspended particulate and bottom sediments, over the entire basin the soluble fraction contributed on average to >80 % of the total concentration in surface water. Despite not being so frequently detected, certain insecticides, mostly deltamethrin, were likewise detected at concentrations above their water-quality guidelines for the protection of aquatic life, even in samples from the main channel. Upon comparison of the pesticide profiles of extensive- and horticultural-production systems in the country, atrazine emerged as a prime candidate to be used as a tracer of extensive agriculture contamination in the environment. Further research is required to establish to what degree pesticides used in agriculture and mobilized by watercourses have an impact on their associated wetland ecosystems.Fil: Mac Loughlin, Tomas Mariano. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigaciones del Medio Ambiente - Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - La Plata. Centro de Investigaciones del Medio Ambiente; ArgentinaFil: Peluso, MarÃa Leticia. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigaciones del Medio Ambiente - Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - La Plata. Centro de Investigaciones del Medio Ambiente; ArgentinaFil: Marino, Damian Jose Gabriel. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigaciones del Medio Ambiente - Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - La Plata. Centro de Investigaciones del Medio Ambiente; Argentin
Case studies:octenidine in the management of diabetic foot ulcers
Diabetic foot ulcers (DFUs) are common and constitute a considerable burdenfor both patients and healthcare providers. Reducing the length of time tohealing reduces the risk of infection and further morbidity. Biofilms delayhealing, therefore, they should be treated with a biofilm-based wound careregimen consisting of debridement, topical agents (antimicrobials and antiseptics)and, if appropriate, systemic antibiotics (Cutting and Westgate, 2012). Thiscase series focuses on the use of octenilin®, which contains a broad-spectrumantimicrobial, in the treatment of DFUs to address bioburden, prevent infectionand progress healing
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