2,169 research outputs found

    Crystal and molecular structure of the discogen bis[1,3-di(p-n- Decylphenyl)propane-1,3-dionato]paliadium(ll)

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    The transition metal containing discogen, bis[1,3-di(p-n-decylphenyl)propane-1 ,3-dionato ]paliadium(II)crystallizes in the triclinic space group pI with one molecule in a unit cell of dimensions a = 10.260(2), b = 12.961(2), c = 13.403(2)A., ex= 110.54(1), f3= 101.75(1) and 'I = 98.44(lt. The crystal structure was solved by direct methods and refined using full matrix least squares procedure. The palladium atom is lying on an inversion center. The decyl chains are fully extended in an all trans conformation. In the crystal structure, the molecules form a tilted columnar arrangement. The angle between the normal to the core and the column axis is 68xB0;. Each column is surrounded by six others. Along the13; column axis, adjacent palladium atoms are separated by 10.26A

    Study of etiological patterns and various clinical presentations of anemia in children aged 6 months to 5 years admitted in a tertiary care hospital

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    Background: Nutritional anemia (NA) is the commonest cause of anemia in children. Iron deficiency is the most important contributing factor to nutritional anemia. Severe iron deficiency is associated with impaired brain development along with cognitive, behavioural, and psychomotor manifestations, particularly during the first two years. This study aimed to evaluate the clinical and etiological profile of anemia in children aged 6 months to 5 years. Material and methods: Hospital-based observational study conducted on children between 6 months to 5 years of age, admitted to Government General Hospital, Srikakulam and having anemia according to WHO classification. Results: Of the 157 children diagnosed with anemia over 18 months period, iron deficiency anemia is the commonest cause of anemia, seen in 107 children followed by sickle cell anemia seen in 21 children. Out of the sampled children, 154 children recovered, and 3 children succumbed to death. Conclusion: Nutritional anemia, particularly iron deficiency anemia is the most common type of anemia in 6 months to 5 years-old children. Co-morbidities like malnutrition, parasitic infestations, diarrheal diseases, and recurrent respiratory tract infections form a vicious cycle and result in nutritional anemia. Identifying the factors that are leading to iron deficiency anemia and implementing the control measures like early iron supplementation results in reducing morbidity and mortality

    On Unbounded Composition Operators in L2L^2-Spaces

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    Fundamental properties of unbounded composition operators in L2L^2-spaces are studied. Characterizations of normal and quasinormal composition operators are provided. Formally normal composition operators are shown to be normal. Composition operators generating Stieltjes moment sequences are completely characterized. The unbounded counterparts of the celebrated Lambert's characterizations of subnormality of bounded composition operators are shown to be false. Various illustrative examples are supplied

    Reinforcement learning or active inference?

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    This paper questions the need for reinforcement learning or control theory when optimising behaviour. We show that it is fairly simple to teach an agent complicated and adaptive behaviours using a free-energy formulation of perception. In this formulation, agents adjust their internal states and sampling of the environment to minimize their free-energy. Such agents learn causal structure in the environment and sample it in an adaptive and self-supervised fashion. This results in behavioural policies that reproduce those optimised by reinforcement learning and dynamic programming. Critically, we do not need to invoke the notion of reward, value or utility. We illustrate these points by solving a benchmark problem in dynamic programming; namely the mountain-car problem, using active perception or inference under the free-energy principle. The ensuing proof-of-concept may be important because the free-energy formulation furnishes a unified account of both action and perception and may speak to a reappraisal of the role of dopamine in the brain

    The interplay of intrinsic and extrinsic bounded noises in genetic networks

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    After being considered as a nuisance to be filtered out, it became recently clear that biochemical noise plays a complex role, often fully functional, for a genetic network. The influence of intrinsic and extrinsic noises on genetic networks has intensively been investigated in last ten years, though contributions on the co-presence of both are sparse. Extrinsic noise is usually modeled as an unbounded white or colored gaussian stochastic process, even though realistic stochastic perturbations are clearly bounded. In this paper we consider Gillespie-like stochastic models of nonlinear networks, i.e. the intrinsic noise, where the model jump rates are affected by colored bounded extrinsic noises synthesized by a suitable biochemical state-dependent Langevin system. These systems are described by a master equation, and a simulation algorithm to analyze them is derived. This new modeling paradigm should enlarge the class of systems amenable at modeling. We investigated the influence of both amplitude and autocorrelation time of a extrinsic Sine-Wiener noise on: (i)(i) the Michaelis-Menten approximation of noisy enzymatic reactions, which we show to be applicable also in co-presence of both intrinsic and extrinsic noise, (ii)(ii) a model of enzymatic futile cycle and (iii)(iii) a genetic toggle switch. In (ii)(ii) and (iii)(iii) we show that the presence of a bounded extrinsic noise induces qualitative modifications in the probability densities of the involved chemicals, where new modes emerge, thus suggesting the possibile functional role of bounded noises

    Investigation of attentional bias in obsessive compulsive disorder with and without depression in visual search

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    Copyright: © 2013 Morein-Zamir et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedWhether Obsessive Compulsive Disorder (OCD) is associated with an increased attentional bias to emotive stimuli remains controversial. Additionally, it is unclear whether comorbid depression modulates abnormal emotional processing in OCD. This study examined attentional bias to OC-relevant scenes using a visual search task. Controls, non-depressed and depressed OCD patients searched for their personally selected positive images amongst their negative distractors, and vice versa. Whilst the OCD groups were slower than healthy individuals in rating the images, there were no group differences in the magnitude of negative bias to concern-related scenes. A second experiment employing a common set of images replicated the results on an additional sample of OCD patients. Although there was a larger bias to negative OC-related images without pre-exposure overall, no group differences in attentional bias were observed. However, OCD patients subsequently rated the images more slowly and more negatively, again suggesting post-attentional processing abnormalities. The results argue against a robust attentional bias in OCD patients, regardless of their depression status and speak to generalized difficulties disengaging from negative valence stimuli. Rather, post-attentional processing abnormalities may account for differences in emotional processing in OCD.Peer reviewedFinal Published versio

    A mathematical model for breath gas analysis of volatile organic compounds with special emphasis on acetone

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    Recommended standardized procedures for determining exhaled lower respiratory nitric oxide and nasal nitric oxide have been developed by task forces of the European Respiratory Society and the American Thoracic Society. These recommendations have paved the way for the measurement of nitric oxide to become a diagnostic tool for specific clinical applications. It would be desirable to develop similar guidelines for the sampling of other trace gases in exhaled breath, especially volatile organic compounds (VOCs) which reflect ongoing metabolism. The concentrations of water-soluble, blood-borne substances in exhaled breath are influenced by: (i) breathing patterns affecting gas exchange in the conducting airways; (ii) the concentrations in the tracheo-bronchial lining fluid; (iii) the alveolar and systemic concentrations of the compound. The classical Farhi equation takes only the alveolar concentrations into account. Real-time measurements of acetone in end-tidal breath under an ergometer challenge show characteristics which cannot be explained within the Farhi setting. Here we develop a compartment model that reliably captures these profiles and is capable of relating breath to the systemic concentrations of acetone. By comparison with experimental data it is inferred that the major part of variability in breath acetone concentrations (e.g., in response to moderate exercise or altered breathing patterns) can be attributed to airway gas exchange, with minimal changes of the underlying blood and tissue concentrations. Moreover, it is deduced that measured end-tidal breath concentrations of acetone determined during resting conditions and free breathing will be rather poor indicators for endogenous levels. Particularly, the current formulation includes the classical Farhi and the Scheid series inhomogeneity model as special limiting cases.Comment: 38 page
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