602 research outputs found

    Preferred Basis in a Measurement Process

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    The effect of decoherence is analysed for a free particle, interacting with an environment via a dissipative coupling. The interaction between the particle and the environment occurs by a coupling of the position operator of the particle with the environmental degrees of freedom. By examining the exact solution of the density matrix equation one finds that the density matrix becomes completely diagonal in momentum with time while the position space density matrix remains nonlocal. This establishes the momentum basis as the emergent 'preferred basis' selected by the environment which is contrary to the general expectation that position should emerge as the preferred basis since the coupling with the environment is via the position coordinate.Comment: Standard REVTeX format, 10 pages of output. Accepted for publication in Phys. Rev

    In Situ Ultrasound Acoustic Measurement of the Lithium-Ion Battery Electrode Drying Process

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    The electrode drying process is a crucial step in the manufacturing of lithium-ion batteries and can significantly affect the performance of an electrode once stacked in a cell. High drying rates may induce binder migration, which is largely governed by the temperature. Additionally, elevated drying rates will result in a heterogeneous distribution of the soluble and dispersed binder throughout the electrode, potentially accumulating at the surface. The optimized drying rate during the electrode manufacturing process will promote balanced homogeneous binder distribution throughout the electrode film; however, there is a need to develop more informative in situ metrologies to better understand the dynamics of the drying process. Here, ultrasound acoustic-based techniques were developed as an in situ tool to study the electrode drying process using NMC622-based cathodes and graphite-based anodes. The drying dynamic evolution for cathodes dried at 40 and 60 °C and anodes dried at 60 °C were investigated, with the attenuation of the reflective acoustic signals used to indicate the evolution of the physical properties of the electrode-coating film. The drying-induced acoustic signal shifts were discussed critically and correlated to the reported three-stage drying mechanism, offering a new mode for investigating the dynamic drying process. Ultrasound acoustic-based measurements have been successfully shown to be a novel in situ metrology to acquire dynamic drying profiles of lithium-ion battery electrodes. The findings would potentially fulfil the research gaps between acquiring dynamic data continuously for a drying mechanism study and the existing research metrology, as most of the published drying mechanism research studies are based on simulated drying processes. It shows great potential for further development and understanding of the drying process to achieve a more controllable electrode manufacturing process

    The cucumber long hypocotyl mutant lacks a light-stable PHYB-like phytochrome

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    A novel cDNA sequence homologous to a phytochrome B (phyB) gene that was isolated in a library from tobacco tissue has been used in an Escherichia coli expression system to raise anti-phytochrome B (anti-PHYB) polypeptide-specific monoclonal antibodies. The specificity of these antibodies has been tested by cross-reactivity against purified pea light-labile type 1 and light-stable type 2 phytochromes, with some antibodies reacting with the type 2 and none with the type 1 phytochromes. One such antibody, monoclonal mAT1, has been employed to analyze the phytochrome molecular species present in a photomorphogenic long hypocotyl (lh) mutant of cucumber. The results indicated that the mutant contains wild-type levels of the light-labile type 1 phytochrome polypeptide (PHYA), which has an apparent molecular mass of approximately 120 kD, but shows less than 1% (detection limit) of a light-stable polypeptide recognized by mAT1 in wild-type seedlings. This protein, not detectable in the lh mutant, has the properties of light-stable type 2 phytochrome, has an apparent molecular mass of 116 to 117 kD, and remains at constant levels under continuous low-fluence-rate red light. Therefore, we conclude that the lh mutant lacks at least one type 2 phytochrome-like polypeptide, most probably a phyB gene product. The correlation between the lack of this protein and the deficiency or absence of physiological responses to a light-stable phytochrome species in this mutant helps to identify the physiological roles played by the products of different subfamilies within the phytochrome gene family

    Parental perceptions of barriers and facilitators to preventing child unintentional injuries within the home: a qualitative study

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    Background Childhood unintentional injury represents an important global health problem. Most of these injuries occur at home, and many are preventable. The main aim of this study was to identify key facilitators and barriers for parents in keeping their children safe from unintentional injury within their homes. A further aim was to develop an understanding of parents’ perceptions of what might help them to implement injury prevention activities. Methods Semi-structured interviews were conducted with sixty-four parents with a child aged less than five years at parent’s homes. Interview data was transcribed verbatim, and thematic analysis was undertaken. This was a Multi-centre qualitative study conducted in four study centres in England (Nottingham, Bristol, Norwich and Newcastle). Results Barriers to injury prevention included parents’ not anticipating injury risks nor the consequences of some risk-taking behaviours, a perception that some injuries were an inevitable part of child development, interrupted supervision due to distractions, maternal fatigue and the presence of older siblings, difficulties in adapting homes, unreliability and cost of safety equipment and provision of safety information later than needed in relation to child age and development. Facilitators for injury prevention included parental supervision and teaching children about injury risks. This included parents’ allowing children to learn about injury risks through controlled risk taking, using “safety rules” and supervising children to ensure that safety rules were adhered to. Adapting the home by installing safety equipment or removing hazards were also key facilitators. Some parents felt that learning about injury events through other parents’ experiences may help parents anticipate injury risks. Conclusions There are a range of barriers to, and facilitators for parents undertaking injury prevention that would be addressable during the design of home safety interventions. Addressing these in future studies may increase the effectiveness of interventions

    Individual Recognition in Domestic Cattle (Bos taurus): Evidence from 2D-Images of Heads from Different Breeds

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    BACKGROUND: In order to maintain cohesion of groups, social animals need to process social information efficiently. Visual individual recognition, which is distinguished from mere visual discrimination, has been studied in only few mammalian species. In addition, most previous studies used either a small number of subjects or a few various views as test stimuli. Dairy cattle, as a domestic species allow the testing of a good sample size and provide a large variety of test stimuli due to the morphological diversity of breeds. Hence cattle are a suitable model for studying individual visual recognition. This study demonstrates that cattle display visual individual recognition and shows the effect of both familiarity and coat diversity in discrimination. [br/]METHODOLOGY/PRINCIPAL FINDINGS: We tested whether 8 Prim'Holstein heifers could recognize 2D-images of heads of one cow (face, profiles, (3/4) views) from those of other cows. Experiments were based on a simultaneous discrimination paradigm through instrumental conditioning using food rewards. In Experiment 1, all images represented familiar cows (belonging to the same social group) from the Prim'Holstein breed. In Experiments 2, 3 and 4, images were from unfamiliar (unknown) individuals either from the same breed or other breeds. All heifers displayed individual recognition of familiar and unfamiliar individuals from their own breed. Subjects reached criterion sooner when recognizing a familiar individual than when recognizing an unfamiliar one (Exp 1: 3.1+/-0.7 vs. Exp 2: 5.2+/-1.2 sessions; Z = 1.99, N = 8, P = 0.046). In addition almost all subjects recognized unknown individuals from different breeds, however with greater difficulty. [br/] CONCLUSIONS/SIGNIFICANCE: Our results demonstrated that cattle have efficient individual recognition based on categorization capacities. Social familiarity improved their performance. The recognition of individuals with very different coat characteristics from the subjects was the most difficult task. These results call for studies exploring the mechanisms involved in face recognition allowing interspecies comparisons, including humans

    Exclusion Performance in Dwarf Goats (Capra aegagrus hircus) and Sheep (Ovis orientalis aries)

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    Using a comparative approach, we investigated the ability of dwarf goats and sheep to use direct and indirect information about the location of a food reward in an object-choice task. Subjects had to choose between two cups with only one covering a reward. Before making a choice, subjects received information about the baited (direct information) or non-baited cup (indirect information). Both goats and sheep were able to use direct information (presence of food) in the object choice task. After controlling for local enhancement, we found that goats rather than sheep were able to use indirect information (i.e., the absence of food) to find a reward. The actual test setup could not clarify whether individual goats were able to inferentially reason about the content of the baited cup when only shown the content of the non-baited cup or if they simply avoided the empty cup in that situation. As browsing species, feral and wild goats exhibit highly selective feeding behaviour compared to the rather unselective grazing sheep. The potential influence of this species-specific foraging flexibility of goats and sheep for using direct and indirect information to find a food reward is discussed in relation to a higher aversion to losses in food acquisition in goats compared to sheep

    Process evaluation for complex interventions in primary care: understanding trials using the normalization process model

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    Background: the Normalization Process Model is a conceptual tool intended to assist in understanding the factors that affect implementation processes in clinical trials and other evaluations of complex interventions. It focuses on the ways that the implementation of complex interventions is shaped by problems of workability and integration.Method: in this paper the model is applied to two different complex trials: (i) the delivery of problem solving therapies for psychosocial distress, and (ii) the delivery of nurse-led clinics for heart failure treatment in primary care.Results: application of the model shows how process evaluations need to focus on more than the immediate contexts in which trial outcomes are generated. Problems relating to intervention workability and integration also need to be understood. The model may be used effectively to explain the implementation process in trials of complex interventions.Conclusion: the model invites evaluators to attend equally to considering how a complex intervention interacts with existing patterns of service organization, professional practice, and professional-patient interaction. The justification for this may be found in the abundance of reports of clinical effectiveness for interventions that have little hope of being implemented in real healthcare setting

    Genetic determinants of co-accessible chromatin regions in activated T cells across humans.

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    Over 90% of genetic variants associated with complex human traits map to non-coding regions, but little is understood about how they modulate gene regulation in health and disease. One possible mechanism is that genetic variants affect the activity of one or more cis-regulatory elements leading to gene expression variation in specific cell types. To identify such cases, we analyzed ATAC-seq and RNA-seq profiles from stimulated primary CD4+ T cells in up to 105 healthy donors. We found that regions of accessible chromatin (ATAC-peaks) are co-accessible at kilobase and megabase resolution, consistent with the three-dimensional chromatin organization measured by in situ Hi-C in T cells. Fifteen percent of genetic variants located within ATAC-peaks affected the accessibility of the corresponding peak (local-ATAC-QTLs). Local-ATAC-QTLs have the largest effects on co-accessible peaks, are associated with gene expression and are enriched for autoimmune disease variants. Our results provide insights into how natural genetic variants modulate cis-regulatory elements, in isolation or in concert, to influence gene expression
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