5,056 research outputs found
Behavioral and neural signatures of working memory in childhood
Working memory function changes across development and varies across individuals. The patterns of behavior and brain function that track individual differences in working memory during human development, however, are not well understood. Here, we establish associations between working memory, other cognitive abilities, and functional MRI (fMRI) activation in data from over 11,500 9- to 10-year-old children (both sexes) enrolled in the Adolescent Brain Cognitive Development (ABCD) Study, an ongoing longitudinal study in the United States. Behavioral analyses reveal robust relationships between working memory, short-term memory, language skills, and fluid intelligence. Analyses relating out-of-scanner working memory performance to memory-related fMRI activation in an emotiona
Lineages of the Islamic State: an international historical sociology of state (de-)formation in Iraq
Existing accounts of the Islamic State (IS) tend to rely on orientalist and technicist assumptions and hence insufficiently sensitive to the historical, sociological, and international conditions of the possibility of IS. The present article provides an alternative account through a conjunctural analysis that is anchored in an international historical sociology of modern Iraq informed by Leon Trotsky's idea of âuneven and combined developmentâ. It foregrounds the concatenation of Iraq's contradictory (postâ)colonial nationâstate formation with the neoliberal conjuncture of 1990â2014. It shows that the former process involved the tensionâprone fusion of governing institutions of the modern state and the intermittent but steady reproduction, valorization, and politicization of supraânational (religiousâsectarian) and subânational (ethnoâtribal) collective identities, which subverted the emergence of an Iraqi nation. The international sanctions regime of the 1990s transformed sectarian and tribal difference into communitarian tension by fatally undermining the integrative efficacy of the Baâath party's authoritarian welfareâstate. Concurrently, the neoâliberal demolition of the postâcolonial authoritarian welfare states in the region gave rise to the Arab Spring revolutions. The Arab Spring however elicited a successful authoritarian counterârevolution that eliminated secularânationalist forms of oppositional politics. This illiberal neoliberalisation of the region's political economy valorised the religionisation of the domestic effects of the 2003 USâled destruction of the Iraqi state and its reconstruction on a majoritarian basis favouring the Shiâas and hence transforming sectarian tension into sectarian conflict culminating in IS. Thus, IS is, the paper demonstrates, the result of neither an internal cultural pathology nor sheerly external forces. Rather, it is the novel product of an utterly historical congealment of the intrinsically interactive and multilinear dynamics of socioâpolitical change
Field Study and Multimethod Analysis of an EV Battery System Disassembly
In the coming decades, the number of end-of-life (EoL) traction battery systems will increase sharply. The disassembly of the system to the battery module is necessary to recycle the battery modules or to be able to use them for further second-life applications. These different recovery paths are important pathways to archive a circular battery supply chain. So far, little knowledge about the disassembling of EoL batteries exists. Based on a disassembly experiment of a plug-in hybrid battery system, we present results regarding the battery set-up, including their fasteners, the necessary disassembly steps, and the sequence. Upon the experimental data, we assess the disassembly duration of the battery system under uncertainty with a fuzzy logic approach. The results indicate that a disassembling time of about 22 min is expected for the battery system in the field study if one worker conducts the process. An estimation for disassembling costs per battery system is performed for a plant in Germany. Depending on the plant capacity, the disassembling to battery module level is associated with costs between EUR 80 and 100 per battery system
Control of atomic currents using a quantum stirring device
We propose a BEC stirring device which can be regarded as the incorporation
of a quantum pump into a closed circuit: it produces a DC circulating current
in response to a cyclic adiabatic change of two control parameters of an
optical trap. We demonstrate the feasibility of this concept and point out that
such device can be utilized in order to probe the interatomic interactions.Comment: 5 pages, 4 figures, uses epl2.cls, revised versio
Cluster Structure on Generalized Weyl Algebras
We introduce a class of non-commutative algebras that carry a non-commutative
(geometric) cluster structure which are generated by identical copies of
generalized Weyl algebras. Equivalent conditions for the finiteness of the set
of the cluster variables of these cluster structures are provided. Some
combinatorial data, called \textit{cluster strands,} arising from the cluster
structure are used to construct irreducible representations of generalized Weyl
algebras.Comment: in Algebras and Representation Theory, Volume 19, No1, Feb. 201
Catalysis by hen egg-white lysozyme proceeds via a covalent intermediate
Hen egg-white lysozyme (HEWL) was the first enzyme to have its three-dimensional structure determined by X-ray diffraction techniques(1). A catalytic mechanism, featuring a long-lived oxo-carbenium-ion intermediate, was proposed on the basis of model-building studies(2). The `Phillips' mechanism is widely held as the paradigm for the catalytic mechanism of beta -glycosidases that cleave glycosidic linkages with net retention of configuration of the anomeric centre. Studies with other retaining beta -glycosidases, however, provide strong evidence pointing to a common mechanism for these enzymes that involves a covalent glycosyl-enzyme intermediate, as previously postulated(3). Here we show, in three different cases using electrospray ionization mass spectrometry, a catalytically competent covalent glycosyl-enzyme intermediate during the catalytic cycle of HEWL. We also show the three-dimensional structure of this intermediate as determined by Xray diffraction. We formulate a general catalytic mechanism for all retaining beta -glycosidases that includes substrate distortion, formation of a covalent intermediate, and the electrophilic migration of C1 along the reaction coordinate
Relationship between body mass index and womenâs body image, self-esteem and eating behaviours in pregnancy: A cross-cultural study
This study examined the relationship between self-esteem, restrained eating, body image and body mass index during pregnancy. A total of 110 pregnant Israeli and UK women completed the Rosenberg Self-Esteem Questionnaire, the Dutch Eating Behaviour Questionnaire, scales to assess body image and demographics. Body mass index was calculated from antenatal records. Regression modelling determined the relationship between variables, countries and body mass index categories. High correlations were found between body image and body mass index with significantly higher body dissatisfaction for Israeli women. Self-esteem scores for pregnant women were similar to those reported for non-pregnant women. Poorer body image and higher prevalence of restrained eating were found in healthy weight Israeli women
Overstating the evidence - double counting in meta-analysis and related problems
Background: The problem of missing studies in meta-analysis has received much attention. Less attention has been paid to the more serious problem of double counting of evidence.
Methods: Various problems in overstating the precision of results from meta-analyses are described and illustrated with examples, including papers from leading medical journals. These problems include, but are not limited to, simple double-counting of the same studies, double counting of some aspects of the studies, inappropriate imputation of results, and assigning spurious precision to individual studies.
Results: Some suggestions are made as to how the quality and reliability of meta-analysis can be improved. It is proposed that the key to quality in meta-analysis lies in the results being transparent and checkable.
Conclusions: Existing quality check lists for meta-analysis do little to encourage an appropriate attitude to combining evidence and to statistical analysis. Journals and other relevant organisations should encourage authors to make data available and make methods explicit. They should also act promptly to withdraw meta-analyses when mistakes are found
Trace as an alternative decategorification functor
Categorification is a process of lifting structures to a higher categorical
level. The original structure can then be recovered by means of the so-called
"decategorification" functor. Algebras are typically categorified to additive
categories with additional structure and decategorification is usually given by
the (split) Grothendieck group. In this expository article we study an
alternative decategorification functor given by the trace or the zeroth
Hochschild--Mitchell homology. We show that this form of decategorification
endows any 2-representation of the categorified quantum sl(n) with an action of
the current algebra U(sl(n)[t]) on its center.Comment: 47 pages with tikz figures. arXiv admin note: text overlap with
arXiv:1405.5920 by other author
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