337 research outputs found

    Asymmetric visual input and route recapitulation in homing pigeons

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    Pigeons (Columba livia) display reliable homing behaviour, but their homing routes from familiar release points are individually idiosyncratic and tightly recapitulated, suggesting that learning plays a role in route establishment. In light of the fact that routes are learned, and that both ascending and des- cending visual pathways share visual inputs from each eye asymmetrically to the brain hemispheres, we investigated how information from each eye con- tributes to route establishment, and how information input is shared between left and right neural systems. Using on-board global positioning system loggers, we tested 12 pigeons’ route fidelity when switching from learning a route with one eye to homing with the other, and back, in an A-B-A design. Two groups of birds, trained first with the left or first with the right eye, formed new idiosyncratic routes after switching eyes, but those that flew first with the left eye formed these routes nearer to their original routes. This confirms that vision plays a major role in homing from familiar sites and exposes a behavioural consequence of neuroanatomical asymmetry whose ontogeny is better understood than its functional significance

    Study of cationic N-isopropylacrylamide-styrene copolymer latex particles using fluorescent probes

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    Monodisperse cationically charged core-shell poly[styrene/N-isopropylacrylamide] latexes, differing in their shell structure, were studied at temperatures around the lower critical solution temperature (LCST) of poly[N-isopropylacrylamide]. Near the LCST, a transition on the latex dimensions was observed by quasi-elastic light scattering measurements. The same transition could also be detected using the intensity ratio of the pyrene fluorescence vibronic bands, I1/I3, and the excimer to monomer fluorescence intensity ratio of 1,10-bis(1-pyrenyl)decane. The fluorescence spectra and decay curve measurements of 1,10-bis-(1-pyrenyl)decane provided a better understanding of both the hydrophilic-hydrophobic variation and the conformational changes occurring in the poly[N-isopropylacrylamide] shell of the latex particles upon temperature variation.J. M. G. Martinho is grateful for the support of this work from FCT. E. M. S. Castanheira acknowledges FCT for a grant (PRAXIS XXI/BPD/9968/96)

    Anharmonic transitions in nearly dry L-cysteine I

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    Two special dynamical transitions of universal character have been recently observed in macromolecules at TD∼180−220T_{D}\sim 180 - 220 K and T∗∼100T^{*}\sim 100 K. Despite their relevance, a complete understanding of the nature of these transitions and their consequences for the bio-activity of the macromolecule is still lacking. Our results and analysis concerning the temperature dependence of structural, vibrational and thermodynamical properties of the orthorhombic polymorph of the amino acid L-cysteine (at a hydration level of 3.5%) indicated that the two referred temperatures define the triggering of very simple and specific events that govern all the biochemical interactions of the biomolecule: activation of rigid rotors (T<T∗T<T^{*}), phonon-phonon interactions with phonons of water dimer (T∗<T<TDT^{*}<T<T_{D}), and water rotational barriers surpassing (T>TDT>T_{D}).Comment: 4 pages, 4 figures, submitted to Physical Review Letter

    Spin diffusion in geometrically frustrated Heisenberg antiferromagnets

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    We investigate spin diffusion in geometrically frustrated Heisenberg antiferromagnets. It is found that the diffusion constant gradually increases from its high temperature limit as the temperature approaches the peak temperature of the susceptibility. Below the peak, the exponential decrease in the susceptibility leads to a rapid increase in the rate of spin diffusion. Detailed results are presented for the pyrochlore lattice with nearest-neighbor interactions.Comment: To appear in J. Phys.: Condensed Matte

    Evolução estrutural na agropecuária da Amazônia brasileira entre 2006 e 2017.

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    RESUMO: Este trabalho tem o objetivo de avaliar as mudanças estruturais do setor agropecuário dentro do bioma Amazônia do Brasil entre os anos 2006 e 2017. Especificamente, ao longo de 11 anos buscou-se identificar a evolução de aspectos agrário, socioeconômico, estrutural, tecnológico e ambiental dos estabelecimentos agropecuários da Amazônia e verificar a existência de padrões espaciais no território amazônico. A metodologia utilizada tem natureza descritiva, exploratória e explicativa, através de levantamento bibliográfico e documental e análise do banco de dados dos Censos Agropecuários de 2006 e 2017. Os resultados indicam que mudanças estruturais significativas que ocorreram no setor agropecuário se refletiram na agropecuária da Amazônia em nível nacional, especialmente, do ponto de vista econômico e produtivo, denotando que o setor tem se expandido dentro do bioma mesmo frente aos limites da legislação ambiental. Por outro lado, ainda que o perfil tecnológico e as condições estruturais também tenham impactado as transformações na agropecuária da Amazônia, de forma geral, a região ainda continua atrasada em relação ao perfil tecnológico brasileiro e demanda por inovações tecnológicas frente a realidade local. ABSTRACT: This work aims to evaluate the structural changes in the agricultural sector in the Amazon biome of Brazil between 2006 and 2017. Specifically, we sought to identify the evolution of the agrarian, socio-economic, structural, technological and environmental aspects of agricultural holdings in the Amazon over 11 years, and to verify the existence of spatial patterns in the Amazon territory. The methodology used is descriptive, exploratory and explanatory, through bibliographic and documentary research and analysis of the brazilian Agricultural Census of the years of 2006 and 2017. The results show that there have been significant structural changes in the agricultural sector, which have been reflected in agriculture and cattle ranching in the Amazon at the national level, especially from an economic and productive point of view, indicating that the sector has expanded within the biome, even within the limits of environmental legislation. On the other hand, although the technological profile and structural conditions have also influenced the transformations in Amazon agriculture and cattle ranching, in general, the region continues to lag behind in terms of the Brazilian technological profile and the demand for technological innovation in relation to the local reality

    Multidisciplinary Development and Initial Validation of a Clinical Knowledge Base on Chronic Respiratory Diseases for mHealth Decision Support Systems

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    Most mobile health (mHealth) decision support systems currently available for chronic obstructive respiratory diseases (CORDs) are not supported by clinical evidence or lack clinical validation. The development of the knowledge base that will feed the clinical decision support system is a crucial step that involves the collection and systematization of clinical knowledge from relevant scientific sources and its representation in a human-understandable and computer-interpretable way. This work describes the development and initial validation of a clinical knowledge base that can be integrated into mHealth decision support systems developed for patients with CORDs. A multidisciplinary team of health care professionals with clinical experience in respiratory diseases, together with data science and IT professionals, defined a new framework that can be used in other evidence-based systems. The knowledge base development began with a thorough review of the relevant scientific sources (eg, disease guidelines) to identify the recommendations to be implemented in the decision support system based on a consensus process. Recommendations were selected according to predefined inclusion criteria: (1) applicable to individuals with CORDs or to prevent CORDs, (2) directed toward patient self-management, (3) targeting adults, and (4) within the scope of the knowledge domains and subdomains defined. Then, the selected recommendations were prioritized according to (1) a harmonized level of evidence (reconciled from different sources); (2) the scope of the source document (international was preferred); (3) the entity that issued the source document; (4) the operability of the recommendation; and (5) health care professionals' perceptions of the relevance, potential impact, and reach of the recommendation. A total of 358 recommendations were selected. Next, the variables required to trigger those recommendations were defined (n=116) and operationalized into logical rules using Boolean logical operators (n=405). Finally, the knowledge base was implemented in an intelligent individualized coaching component and pretested with an asthma use case. Initial validation of the knowledge base was conducted internally using data from a population-based observational study of individuals with or without asthma or rhinitis. External validation of the appropriateness of the recommendations with the highest priority level was conducted independently by 4 physicians. In addition, a strategy for knowledge base updates, including an easy-to-use rules editor, was defined. Using this process, based on consensus and iterative improvement, we developed and conducted preliminary validation of a clinical knowledge base for CORDs that translates disease guidelines into personalized patient recommendations. The knowledge base can be used as part of mHealth decision support systems. This process could be replicated in other clinical areas.info:eu-repo/semantics/publishedVersio

    Candida species contamination of preservation fluid-outcome of renal transplantation in 6 patients

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    BACKGROUND: Fungal infections are a rare but important cause of morbidity and mortality in kidney transplantation. Fungal contamination of the kidney preservation fluid may, sometimes, be the cause of these infections. However, the clinical consequences of fungal contamination of this fluid are not completely understood and literature on this topic is controversial. The purpose of this study was to determine the incidence of preservation fluid contamination by fungi and its clinical consequences. METHODS: From June 2010 to September 2011, a prospective cohort analysis was conducted at our center, enrolling all patients who received a renal allograft and whose perfusion fluid was analyzed for microbiology sterility. Patients with perfusion fluids positive for fungi were further studied: the patients' status was assessed during regular visits and data were recorded, including clinical characteristics, infections, graft function, immunosuppressive regimen and outcomes. RESULTS: Microbiologic, cultures of 70 kidney perfusion fluids using specific mycologic media, obtained from 74 cadaveric renal transplants (4 fluids were unsuitable for analysis), were evaluated. Six samples were positive for yeasts (8.6%), with 4 isolates of Candida albicans and 2 isolates of Candida glabrata. Four patients had no evidence of fungal infection during the follow-up period (median 321 days); conversely, 2 patients developed severe mycotic vascular complications leading to transplantectomy. CONCLUSIONS: Perfusion fluid contamination by fungi is an elusive situation that can lead either to an unremarkable clinical course or to graft loss life-threatening situations. Routine culture of kidney perfusion fluid is critical for prompt diagnosis and early implementation of appropriate treatment

    Searching for phenotypic causal networks involving complex traits: an application to European quail

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    <p>Abstract</p> <p>Background</p> <p>Structural equation models (SEM) are used to model multiple traits and the casual links among them. The number of different causal structures that can be used to fit a SEM is typically very large, even when only a few traits are studied. In recent applications of SEM in quantitative genetics mixed model settings, causal structures were pre-selected based on prior beliefs alone. Alternatively, there are algorithms that search for structures that are compatible with the joint distribution of the data. However, such a search cannot be performed directly on the joint distribution of the phenotypes since causal relationships are possibly masked by genetic covariances. In this context, the application of the Inductive Causation (IC) algorithm to the joint distribution of phenotypes conditional to unobservable genetic effects has been proposed.</p> <p>Methods</p> <p>Here, we applied this approach to five traits in European quail: birth weight (BW), weight at 35 days of age (W35), age at first egg (AFE), average egg weight from 77 to 110 days of age (AEW), and number of eggs laid in the same period (NE). We have focused the discussion on the challenges and difficulties resulting from applying this method to field data. Statistical decisions regarding partial correlations were based on different Highest Posterior Density (HPD) interval contents and models based on the selected causal structures were compared using the Deviance Information Criterion (DIC). In addition, we used temporal information to perform additional edge orienting, overriding the algorithm output when necessary.</p> <p>Results</p> <p>As a result, the final causal structure consisted of two separated substructures: BW→AEW and W35→AFE→NE, where an arrow represents a direct effect. Comparison between a SEM with the selected structure and a Multiple Trait Animal Model using DIC indicated that the SEM is more plausible.</p> <p>Conclusions</p> <p>Coupling prior knowledge with the output provided by the IC algorithm allowed further learning regarding phenotypic causal structures when compared to standard mixed effects SEM applications.</p

    Performance of Anaerobic Co‑digestion of Pig Slurry with Pineapple (Ananas comosus) Bio‑waste Residues

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    Agro-food industries produce large amounts of bio-waste, challenging innovative valorisation strategies in the framework of circular economy principles. Anaerobic digestion technology is an interesting route to stabilise organic matter and produce biogas as a renewable energy source. This paper aimed to study the optimal performance conditions for anaerobic co-digestion (AcoD) of pig slurry with pineapple (Ananas comosus) peel bio-waste. The anaerobic digestion (AD) trials were performed at lab scale, in a continuous stirred reactor, for 16 days’ hydraulic retention time in mesophilic conditions (37 ± 1 °C). Three hydraulic retention time were performed, one for the reference scenario ( T0) and two for AcoD trials ( T1, T2). Feeding mixtures (20:80; v:v) of pineapple peel liquor and pig slurry, with an OLR of 1.46 ± 0.04 g TVS L− 1 reactor day− 1 were used during AD/AcoD trials, presenting high values for soluble chemical oxygen demand and C/N ratio. This operational conditions highlight bioenergy recovery up to 0.58 L CH4 g TVSadded −1, in comparison with that obtained with pig slurry substrate (0.31 L CH4 g VSadded −1). The AD performance showed a total volatile solids and chemical oxygen demand removal efficiency of 23% to 47% and 26% to 48%, comparing T0 with the average of T1 and T2, respectively. The digester stability, evaluated by specific energetic loading rate, was below the limit (0.4 day−1) throughout the trials. Pig slurry co-digestion with pineapple peel liquor seems to be a promising approach for potential bioenergy recovery.info:eu-repo/semantics/publishedVersio
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