536 research outputs found

    From Heisenberg matrix mechanics to EBK quantization: theory and first applications

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    Despite the seminal connection between classical multiply-periodic motion and Heisenberg matrix mechanics and the massive amount of work done on the associated problem of semiclassical (EBK) quantization of bound states, we show that there are, nevertheless, a number of previously unexploited aspects of this relationship that bear on the quantum-classical correspondence. In particular, we emphasize a quantum variational principle that implies the classical variational principle for invariant tori. We also expose the more indirect connection between commutation relations and quantization of action variables. With the help of several standard models with one or two degrees of freedom, we then illustrate how the methods of Heisenberg matrix mechanics described in this paper may be used to obtain quantum solutions with a modest increase in effort compared to semiclassical calculations. We also describe and apply a method for obtaining leading quantum corrections to EBK results. Finally, we suggest several new or modified applications of EBK quantization.Comment: 37 pages including 3 poscript figures, submitted to Phys. Rev.

    Inscribing a discipline: tensions in the field of bioinformatics

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    Bioinformatics, the application of computer science to biological problems, is a central feature of post-genomic science which grew rapidly during the 1990s and 2000s. Post-genomic science is often high-throughput, involving the mass production of inscriptions [Latour and Woolgar (1986), Laboratory Life: the Construction of Scientific Facts. Princeton, NJ: Princeton University Press]. In order to render these mass inscriptions comprehensible, bioinformatic techniques are employed, with bioinformaticians producing what we call secondary inscriptions. However, despite bioinformaticians being highly skilled and credentialed scientists, the field struggles to develop disciplinary coherence. This paper describes two tensions militating against disciplinary coherence. The first arises from the fact that bioinformaticians as producers of secondary inscriptions are often institutionally dependent, subordinate even, to biologists. With bioinformatics positioned as service, it cannot determine its own boundaries but has them imposed from the outside. The second tension is a result of the interdisciplinary origin of bioinformatics – computer science and biology are disciplines with very different cultures, values and products. The paper uses interview data from two different UK projects to describe and examine these tensions by commenting on Calvert's [(2010) “Systems Biology, Interdisciplinarity and Disciplinary Identity.” In Collaboration in the New Life Sciences, edited by J. N. Parker, N. Vermeulen and B. Penders, 201–219. Farnham: Ashgate] notion of individual and collaborative interdisciplinarity and McNally's [(2008) “Sociomics: CESAGen Multidisciplinary Workshop on the Transformation of Knowledge Production in the Biosciences, and its Consequences.” Proteomics 8: 222–224] distinction between “black box optimists” and “black box pessimists.

    Interventions to increase engagement with rehabilitation in adults with acquired brain injury: A systematic review

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    Rehabilitation in adults with acquired brain injury is often hampered by a lack of client engagement with the rehabilitation process, leading to frustration, withdrawal of services and poorer recovery. Motivation, apathy and awareness are potential mechanisms underlying engagement, but few studies have suggested potential intervention techniques. A systematic review of the literature was carried out to identify and evaluate interventions designed to increase rehabilitation engagement in adults with acquired brain injury. Database searches used the following terms: rehabilitation, brain injury, and compliance/engagement/adherence in PsychInfo, Medline, Cinahl, Embase, AMED, Web of Knowledge, PsycBite, Cochrane clinical trials, and clinicaltrials.org. Hand searches were conducted of reference lists and relevant journals. Fifteen studies were included in the review. Intervention techniques fell into two broad categories: behavioural modification techniques and cognitive/meta-cognitive skills. Contingent reward techniques were most effective at increasing adherence and compliance, while interventions enabling clients' active participation in rehabilitation appeared to increase engagement and motivation. The review highlighted methodological and measurement inconsistencies in the field and suggested that interventions should be tailored to clients' abilities and circumstances

    Cytogenotoxicity biomarkers in fat snook Centropomus parallelus from Cananéia and São Vicente estuaries, SP, Brazil

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    The aquatic environment receives many contaminants that can induce damages at the molecular, biochemical, cellular and physiological levels. Centropomus parallelus, an important food resource for local populations, is a predator fish that feeds on small fishes and benthic invertebrates, thus being vulnerable to the bioconcentration and biomagnification processes. This study aimed to evaluate cytogenotoxic responses in erythrocytes from C. parallelus juveniles collected in the Cananéia and São Vicente estuaries, both in winter and in summer. After anesthesia, blood samples were collected by caudal puncture. Blood smears were prepared on glass slides and stained with May-Grünwald-Giemsa dye. Two thousand cells were analyzed per slide (1000x), and nuclear abnormalities (NA) and micronuclei (MN) were scored. The São Vicente sample showed MN and NA frequencies (%/1000 cells) of 0.325 and 3.575, in winter, and of 0.125 and 2.935 in summer respectively; the Cananéia sample showed frequencies of 0.0325 and 0.03, in winter, and of 0.065 and 0.355 in summer, respectively. The rates found in São Vicente were significantly higher than those found in Cananéia, evidencing that the levels of pollution in that estuary were high enough to induce genetic damages

    The effects of an exercise intervention on neuroelectric activity and executive function in children with overweight/obesity:The ActiveBrains randomized controlled trial

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    Objective: To investigate whether a 20-week aerobic and resistance exercise program induces changes in brain current density underlying working memory and inhibitory control in children with overweight/obesity. Methods: A total of 67 children (10.00 ± 1.10 years) were randomized into an exercise or control group. Electroencephalography (EEG)-based current density (μA/mm2) was estimated using standardized low-resolution brain electromagnetic tomography (sLORETA) during a working memory task (Delayed non-matched-to-sample task, DNMS) and inhibitory control task (Modified flanker task, MFT). In DNMS, participants had to memorize four stimuli (Pokemons) and then select between two of them, one of which had not been previously shown. In MFT, participants had to indicate whether the centered cow (i.e., target) of five faced the right or left. Results: The exercise group had significantly greater increases in brain activation in comparison with the control group during the encoding phase of DNMS, particularly during retention of second stimuli in temporal and frontal areas (peak t = from 3.4 to 3.8, cluster size [k] = from 11 to 39), during the retention of the third stimuli in frontal areas (peak t = from 3.7 to 3.9, k = from 15 to 26), and during the retention of the fourth stimuli in temporal and occipital areas (peak t = from 2.7 to 4.3, k = from 13 to 101). In MFT, the exercise group presented a lower current density change in the middle frontal gyrus (peak t = −4.1, k = 5). No significant change was observed between groups for behavioral performance (p ≥ 0.05). Conclusion: A 20-week exercise program modulates brain activity which might provide a positive influence on working memory and inhibitory control in children with overweight/obesity.</p

    Endothelial c-REL orchestrates atherosclerosis at regions of disturbed flow through crosstalk with TXNIP-p38 and non-canonical NF-κB pathways

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    \ua9 The Author(s) 2025. Published by Oxford University Press on behalf of the European Society of Cardiology.Aims Atherosclerosis initiation at sites of disturbed blood flow involves heightened inflammation coupled to excessive endothelial cell (EC) proliferation. Here, we unveil the pivotal role of c-REL, a member of the NF-κB transcription factor family, in orchestrating these processes by driving dual pathological inflammatory and cell cycle pathways. Methods and results Analysis of cultured EC and murine models revealed enrichment and activation of c-REL at atherosusceptible sites experiencing disturbed flow. Transcriptome analysis, extensively validated in vitro and in vivo, demonstrates that endothelial c-REL drives inflammation via a TXNIP-p38 MAP kinase signalling pathway and enhances proliferation through a non-canonical NFKB2-p21 pathway. Consistent with its pivotal role in EC pathology, genetic deletion of c-Rel in EC significantly reduces plaque burden in hypercholesterolaemic mice. Conclusion These findings underscore the fundamental role of c-REL in endothelial responses to disturbed flow and highlight therapeutic targeting of endothelial c-REL as a potential strategy for atherosclerosis treatment

    Epistatic regulation of growth in Atlantic salmon revealed:A QTL study performed on the domesticated-wild interface

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    Background Quantitative traits are typically considered to be under additive genetic control. Although there are indications that non-additive factors have the potential to contribute to trait variation, experimental demonstration remains scarce. Here, we investigated the genetic basis of growth in Atlantic salmon by exploiting the high level of genetic diversity and trait expression among domesticated, hybrid and wild populations. Results After rearing fish in common-garden experiments under aquaculture conditions, we performed a variance component analysis in four mapping populations totaling similar to 7000 individuals from six wild, two domesticated and three F1 wild/domesticated hybrid strains. Across the four independent datasets, genome-wide significant quantitative trait loci (QTLs) associated with weight and length were detected on a total of 18 chromosomes, reflecting the polygenic nature of growth. Significant QTLs correlated with both length and weight were detected on chromosomes 2, 6 and 9 in multiple datasets. Significantly, epistatic QTLs were detected in all datasets. Discussion The observed interactions demonstrated that the phenotypic effect of inheriting an allele deviated between half-sib families. Gene-by-gene interactions were also suggested, where the combined effect of two loci resulted in a genetic effect upon phenotypic variance, while no genetic effect was detected when the two loci were considered separately. To our knowledge, this is the first documentation of epistasis in a quantitative trait in Atlantic salmon. These novel results are of relevance for breeding programs, and for predicting the evolutionary consequences of domestication-introgression in wild populations

    Objective and subjective measures of physical functioning in women with fibromyalgia: what type of measure is associated most clearly with subjective well-being?

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    To find modifiable factors that are related to subjective well-being would be valuable for improving interventions in fibromyalgia. Physical activity, sedentary behaviour, and physical fitness may represent potential areas to optimize treatment regimens. In fibromyalgia, there is a discordance between clinical observations and patient-reported outcomes (objective and subjective assessments). Therefore, the present study aims at analyzing the associations of objective and subjective evaluations of physical activity, sedentary behaviour, and physical fitness with subjective well-being and determine if and how objective and subjective associations differ In the most conservative multivariate analysis, we found independent associations of the objective measures of physical activity with positive affect and life satisfaction and sedentary behaviour with positive affect. No such relationship was seen with subjective measures of the same behaviours. Moreover, we observed that objective and subjective physical fitness evaluations were independent of each other related to subjective well-being. Independent associations of the objectivemeasures (but not the subjective assessments) of physical activity with positive affect and life satisfaction, and of sedentary behaviour with positive affect were observed. However, objective measures and subjective appraisals of physical fitness appear to be independently related to well-being,which should be consideredwhen developing physical exercise interventions for fibromyalgiaThis work was supported by the Spanish Ministry of Economy and Competitiveness [I+D+i DEP2010-15639, I+D+I DEP2013- 40908, and BES-2014–067612]; the Spanish Ministry of Education [FPU15/00002]. This study has been partially funded by the University of Granada, Plan Propio de Investigación 2016, Excellence actions: Units of Excellence; Unit of Excellence on Exercise and Health (UCEES), and by the Junta de Andalucía, Consejería de Conocimiento, Investigación y Universidades and European Regional Development Fund (ERDF), ref. SOMM17/6107/ UGR. This research was supported (in part) by the Intramural Research program of the NIH, National Institute of Nursing Research
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