87 research outputs found

    Study on the vibration characteristics of the telescope T80 in the Javalambre astrophysical observatory (JAO) aimed at detecting invalid images

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    The location of large telescopes, generally far from the data processing centers, represents a logistical problem for the supervision of the capture of images. In this work, we carried out a preliminary study of the vibration signature of the T80 telescope at the Javalambre Astrophysical Observatory (JAO). The study analyzed the process of calculating the displacement that occurs because of the vibration in each of the frequencies in the range of interest. We analyzed the problems associated with very low frequencies by means of simulation, finding the most critical vibrations below 20 Hz, since they are the ones that generate greater displacements. The work also relates previous studies based on simulation with the real measurements of the vibration of the telescope taken remotely when it is subjected to different positioning movements (right ascension and/or declination) or when it performs movement actions such as those related to filter trays or mirror cover. The obtained results allow us to design a remote alarm system to detect invalid images (taken with excess vibration)

    An Alternative Approach to Obtain a New Gain in Step-Size of LMS Filters Dealing with Periodic Signals

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    Partial updates (PU) of adaptive filters have been successfully applied in different contexts to lower the computational costs of many control systems. In a PU adaptive algorithm, only a fraction of the coefficients is updated per iteration. Particularly, this idea has been proved as a valid strategy in the active control of periodic noise consisting of a sum of harmonics. The convergence analysis carried out here is based on the periodic nature of the input signal, which makes it possible to formulate the adaptive process with a matrix-based approach, the periodic least-mean-square (P-LMS) algorithm In this paper, we obtain the upper bound that limits the step-size parameter of the sequential PU P-LMS algorithm and compare it to the bound of the full-update P-LMS algorithm. Thus, the limiting value for the step-size parameter is expressed in terms of the step-size gain of the PU algorithm. This gain in step-size is the quotient between the upper bounds ensuring convergence in the following two scenarios: first, when PU are carried out and, second, when every coefficient is updated during every cycle. This step-size gain gives the factor by which the step-size can be multiplied so as to compensate for the convergence speed reduction of the sequential PU algorithm, which is an inherently slower strategy. Results are compared with previous results based on the standard sequential PU LMS formulation. Frequency-dependent notches in the step-size gain are not present with the matrix-based formulation of the P-LMS. Simulated results confirm the expected behavior

    Modified filtered-x hierarchical lms algorithm with sequential partial updates for active noise control

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    In the field of active noise control (ANC), a popular method is the modified filtered-x LMS algorithm. However, it has two drawbacks: Its computational complexity higher than that of the conventional FxLMS, and its convergence rate that could still be improved. Therefore, we propose an adaptive strategy which aims at speeding up the convergence rate of an ANC system dealing with periodic disturbances. This algorithm consists in combining the organization of the filter weights in a hierarchy of subfilters of shorter length and their sequential partial updates (PU). Our contribution is threefold: (1) we provide the theoretical basis of the existence of a frequency-depend-ent parameter, called gain in step-size. (2) The theoretical upper bound of the step-size is compared with the limit obtained from simulations. (3) Additional experiments show that this strategy results in a fast algorithm with a computational complexity close to that of the conventional FxLMS

    Experiencias de extensión en viviendas de escasos recursos en el sector rural de Tucumán

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    El objetivo del presente trabajo es presentar una experiencia realizada con alumnos y docentes de la Facultad de Arquitectura y Urbanismo de la Universidad Nacional de Tucumán, en relación con instalaciones sanitarias en viviendas rurales de la zona del Valle Calchaquí de la provincia de Tucumán, con incorporación de sistemas de calentamiento de agua solar.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

    Males and females with first episode psychosis present distinct profiles of social cognition and metacognition

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    Altres ajuts: Royal Society of New Zealand - Marsden (E2987-3648) ; Obra Social La Caixa (RecerCaixa call 2013) ; Obra Social Sant Joan de Déu BML (RTI2018-100927-J-I00) ; Ministerio Regional de Salud AndaluzDeficits in social cognition and metacognition impact the course of psychosis. Sex diferences in social cognition and metacognition could explain heterogeneity in psychosis. 174 (58 females) patients with frst-episode psychosis completed a clinical, neuropsychological, social cognitive, and metacognitive assessment. Subsequent latent profle analysis split by sex yielded two clusters common to both sexes (a Homogeneous group, 53% and 79.3%, and an Indecisive group, 18.3% and 8.6% of males and females, respectively), a specifc male profle characterized by presenting jumping to conclusions (28.7%) and a specifc female profle characterized by cognitive biases (12.1%). Males and females in the homogeneous profle seem to have a more benign course of illness. Males with jumping to conclusions had more clinical symptoms and more neuropsychological defcits. Females with cognitive biases were younger and had lower self-esteem. These results suggest that males and females may beneft from specifc targeted treatment and highlights the need to consider sex when planning interventions

    Persons with first episode psychosis have distinct profiles of social cognition and metacognition

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    Altres ajuts: Obra Social La Caixa (RecerCaixa call 2013), by the Agencia Estatal de Investigación (AEI, Spain). Junta de Andalucía: PI-0634/2011; PI-0193/2014.Subjects with first-episode psychosis experience substantial deficits in social cognition and metacognition. Although previous studies have investigated the role of profiles of individuals in social cognition and metacognition in chronic schizophrenia, profiling subjects with first-episode psychosis in both domains remains to be investigated. We used latent profile analysis to derive profiles of the abilities in 174 persons with first-episode psychosis using the Beck's Cognitive Insight Scale, the Faces Test, the Hinting Task, the Internal, Personal and Situational Attributions Questionnaire, and the Beads Task. Participants received a clinical assessment and a neuropsychological assessment. The best-fitting model was selected according to the Bayesian information criterion (BIC). We assessed the importance of the variables via a classification tree (CART). We derived three clusters with distinct profiles. The first profile (33.3%) comprised individuals with low social cognition. The second profile (60.9%) comprised individuals that had more proneness to present jumping to conclusions. The third profile (5.7%) presented a heterogeneous profile of metacognitive deficits. Persons with lower social cognition presented worse clinical and neuropsychological features than cluster 2 and cluster 3. Cluster 3 presented significantly worst functioning. Our results suggest that individuals with FEP present distinct profiles that concur with specific clinical, neuropsychological, and functional challenges. Each subgroup may benefit from different interventions

    Treatment of rats with a self-selected hyperlipidic diet, increases the lipid content of the main adipose tissue sites in a proportion similar to that of the lipids in the rest of organs and tissues

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    Adipose tissue (AT) is distributed as large differentiated masses, and smaller depots covering vessels, and organs, as well as interspersed within them. The differences between types and size of cells makes AT one of the most disperse and complex organs. Lipid storage is partly shared by other tissues such as muscle and liver. We intended to obtain an approximate estimation of the size of lipid reserves stored outside the main fat depots. Both male and female rats were made overweight by 4-weeks feeding of a cafeteria diet. Total lipid content was analyzed in brain, liver, gastrocnemius muscle, four white AT sites: subcutaneous, perigonadal, retroperitoneal and mesenteric, two brown AT sites (interscapular and perirenal) and in a pool of the rest of organs and tissues (after discarding gut contents). Organ lipid content was estimated and tabulated for each individual rat. Food intake was measured daily. There was a surprisingly high proportion of lipid not accounted for by the main macroscopic AT sites, even when brain, liver and BAT main sites were discounted. Muscle contained about 8% of body lipids, liver 1-1.4%, four white AT sites lipid 28-63% of body lipid, and the rest of the body (including muscle) 38-44%. There was a good correlation between AT lipid and body lipid, but lipid in"other organs" was highly correlated too with body lipid. Brain lipid was not. Irrespective of dietary intake, accumulation of body fat was uniform both for the main lipid storage and handling organs: large masses of AT (but also liver, muscle), as well as in the"rest" of tissues. These storage sites, in specialized (adipose) or not-specialized (liver, muscle) tissues reacted in parallel against a hyperlipidic diet challenge. We postulate that body lipid stores are handled and regulated coordinately, with a more centralized and overall mechanisms than usually assumed

    Effect of Sex and Prior Exposure to a Cafeteria Diet on the Distribution of Sex Hormones between Plasma and Blood Cells

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    It is generally assumed that steroid hormones are carried in the blood free and/or bound to plasma proteins. We investigated whether blood cells were also able to bind/carry sex-related hormones: estrone, estradiol, DHEA and testosterone. Wistar male and female rats were fed a cafeteria diet for 30 days, which induced overweight. The rats were fed the standard rat diet for 15 additional days to minimize the immediate effects of excess ingested energy. Controls were always kept on standard diet. After the rats were killed, their blood was used for 1) measuring plasma hormone levels, 2) determining the binding of labeled hormones to washed red blood cells (RBC), 3) incubating whole blood with labeled hormones and determining the distribution of label between plasma and packed cells, discounting the trapped plasma volume, 4) determining free plasma hormone using labeled hormones, both through membrane ultrafiltration and dextran-charcoal removal. The results were computed individually for each rat. Cells retained up to 32% estrone, and down to 10% of testosterone, with marked differences due to sex and diet (the latter only for estrogens, not for DHEA and testosterone). Sex and diet also affected the concentrations of all hormones, with no significant diet effects for estradiol and DHEA, but with considerable interaction between both factors. Binding to RBC was non-specific for all hormones. Estrogen distribution in plasma compartments was affected by sex and diet. In conclusion: a) there is a large non-specific RBC-carried compartment for estrone, estradiol, DHEA and testosterone deeply affected by sex; b) Prior exposure to a cafeteria (hyperlipidic) diet induced hormone distribution changes, affected by sex, which hint at sex-related structural differences in RBC membranes; c) We postulate that the RBC compartment may contribute to maintain free (i.e., fully active) sex hormone levels in a way similar to plasma proteins non-specific binding

    Effect of Sex and Prior Exposure to a Cafeteria Diet on the Distribution of Sex Hormones between Plasma and Blood Cells

    Get PDF
    It is generally assumed that steroid hormones are carried in the blood free and/or bound to plasma proteins. We investigated whether blood cells were also able to bind/carry sex-related hormones: estrone, estradiol, DHEA and testosterone. Wistar male and female rats were fed a cafeteria diet for 30 days, which induced overweight. The rats were fed the standard rat diet for 15 additional days to minimize the immediate effects of excess ingested energy. Controls were always kept on standard diet. After the rats were killed, their blood was used for 1) measuring plasma hormone levels, 2) determining the binding of labeled hormones to washed red blood cells (RBC), 3) incubating whole blood with labeled hormones and determining the distribution of label between plasma and packed cells, discounting the trapped plasma volume, 4) determining free plasma hormone using labeled hormones, both through membrane ultrafiltration and dextran-charcoal removal. The results were computed individually for each rat. Cells retained up to 32% estrone, and down to 10% of testosterone, with marked differences due to sex and diet (the latter only for estrogens, not for DHEA and testosterone). Sex and diet also affected the concentrations of all hormones, with no significant diet effects for estradiol and DHEA, but with considerable interaction between both factors. Binding to RBC was non-specific for all hormones. Estrogen distribution in plasma compartments was affected by sex and diet. In conclusion: a) there is a large non-specific RBC-carried compartment for estrone, estradiol, DHEA and testosterone deeply affected by sex; b) Prior exposure to a cafeteria (hyperlipidic) diet induced hormone distribution changes, affected by sex, which hint at sex-related structural differences in RBC membranes; c) We postulate that the RBC compartment may contribute to maintain free (i.e., fully active) sex hormone levels in a way similar to plasma proteins non-specific binding
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