2,166 research outputs found
Non-Locality and Theories of Causation
The aim of the paper is to investigate the characterization of an unambiguous
notion of causation linking single space-llike separated events in EPR-Bell
frameworks. This issue is investigated in ordinary quantum mechanics, with some
hints to no collapse formulations of the theory such as Bohmian mechanics.Comment: Presented at the NATO Advanced Research Workshop on Modality,
Probability and Bell's Theorems, Cracow, Poland, August 19-23, 200
Exponential Random Graph Modeling for Complex Brain Networks
Exponential random graph models (ERGMs), also known as p* models, have been
utilized extensively in the social science literature to study complex networks
and how their global structure depends on underlying structural components.
However, the literature on their use in biological networks (especially brain
networks) has remained sparse. Descriptive models based on a specific feature
of the graph (clustering coefficient, degree distribution, etc.) have dominated
connectivity research in neuroscience. Corresponding generative models have
been developed to reproduce one of these features. However, the complexity
inherent in whole-brain network data necessitates the development and use of
tools that allow the systematic exploration of several features simultaneously
and how they interact to form the global network architecture. ERGMs provide a
statistically principled approach to the assessment of how a set of interacting
local brain network features gives rise to the global structure. We illustrate
the utility of ERGMs for modeling, analyzing, and simulating complex
whole-brain networks with network data from normal subjects. We also provide a
foundation for the selection of important local features through the
implementation and assessment of three selection approaches: a traditional
p-value based backward selection approach, an information criterion approach
(AIC), and a graphical goodness of fit (GOF) approach. The graphical GOF
approach serves as the best method given the scientific interest in being able
to capture and reproduce the structure of fitted brain networks
Vortex arrays in neutral trapped Fermi gases through the BCS–BEC crossover
Vortex arrays in type-II superconductors reflect the translational symmetry of an infinite system. There are cases, however, such as ultracold trapped Fermi gases and the crust of neutron stars, where finite-size effects make it complex to account for the geometrical arrangement of vortices. Here, we self-consistently generate these arrays of vortices at zero and finite temperature through a microscopic description of the non-homogeneous superfluid based on a differential equation for the local order parameter, obtained by coarse graining the Bogoliubov–de Gennes (BdG) equations. In this way, the strength of the inter-particle interaction is varied along the BCS–BEC crossover, from largely overlapping Cooper pairs in the Bardeen–Cooper–Schrieffer (BCS) limit to dilute composite bosons in the Bose–Einstein condensed (BEC) limit. Detailed comparison with two landmark experiments on ultracold Fermi gases, aimed at revealing the presence of the superfluid phase, brings out several features that make them relevant for other systems in nature as well
Assessing architectural evolution: A case study
This is the post-print version of the Article. The official published can be accessed from the link below - Copyright @ 2011 SpringerThis paper proposes to use a historical perspective on generic laws, principles,
and guidelines, like Lehman’s software evolution laws and Martin’s design principles, in order to achieve a multi-faceted process and structural assessment of a system’s architectural evolution. We present a simple structural model with associated historical metrics and
visualizations that could form part of an architect’s dashboard. We perform such an assessment for the Eclipse SDK, as a case study of a large, complex, and long-lived system for which sustained effective architectural evolution is paramount. The twofold aim of checking generic principles on a well-know system is, on the one hand,
to see whether there are certain lessons that could be learned for best practice of architectural evolution, and on the other hand to get more insights about the applicability of such principles. We find that while the Eclipse SDK does follow several of the laws and principles, there are some deviations, and we discuss areas of architectural improvement and limitations of the assessment approach
Paediatric obsessive-compulsive disorder and depressive symptoms: clinical correlates and CBT treatment outcomes.
Depression frequently co-occurs with paediatric obsessive-compulsive disorder (OCD), yet the clinical correlates and impact of depression on CBT outcomes remain unclear. The prevalence and clinical correlates of depression were examined in a paediatric specialist OCD-clinic sample (N = 295; Mean = 15 [7 - 18] years, 42 % female), using both dimensional (Beck Depression Inventory-youth; n = 261) and diagnostic (Development and Wellbeing Assessment; n = 127) measures of depression. The impact of depressive symptoms and suspected disorders on post-treatment OCD severity was examined in a sub-sample who received CBT, with or without SSRI medication (N = 100). Fifty-one per-cent of patients reported moderately or extremely elevated depressive symptoms and 26 % (95 % CI: 18 - 34) met criteria for a suspected depressive disorder. Depressive symptoms and depressive disorders were associated with worse OCD symptom severity and global functioning prior to CBT. Individuals with depression were more likely to be female, have had a psychiatric inpatient admission and less likely to be attending school (ps < 0.01). OCD and depressive symptom severity significantly decreased after CBT. Depressive symptoms and depressive disorders predicted worse post-treatment OCD severity (βs = 0.19 and 0.26, ps < 0.05) but became non-significant when controlling for pre-treatment OCD severity (βs = 0.05 and 0.13, ns). Depression is common in paediatric OCD and is associated with more severe OCD and poorer functioning. However, depression severity decreases over the course of CBT for OCD and is not independently associated with worse outcomes, supporting the recommendation for treatment as usual in the presence of depressive symptoms
Different expressions of AQP1, AQP4, eNOS, and VEGF proteins in ischemic versus non-ischemic cerebropathy in rats: potential roles of AQP1 and eNOS in hydrocephalic and vasogenic edema formation
In this study, expressions of aquaporin (AQP) 1, AQP4, endothelial nitric oxide synthase (eNOS), and vascular endothelial growth factor in blood-cerebrospinal fluid (CSF) barrier and blood-brain barrier (BBB) are examined in rat choroid plexus and peri-infarcted hippocampal formation (HF) following systemic hyponatremia (SH) and permanent middle cerebral artery occlusion (pMCAO). These events are thought to cause the development of hydrocephalic and vasogenic edemas. The importance of CSF overproduction and intact blood-CSF barrier during hydrocephalic edema formation is demonstrated by the high expression of AQP1 (329.86±10.2%, n=4 , P<0.01) and trapped plasma immunoglobulin G (IgG) in choroid plexus epithelium after 24 hours of SH. However, the increased eNOS expression in peri-infarcted HF (130±3%, n=4, P<0.01) and extravasation of plasma IgG into the extravascular compartment after 24 hours of pMCAO suggest that increased microvascular permeability, probably due to elevated levels of nitric oxide, leads to development of vasogenic brain edema via BBB breakdown. Based on these findings, the authors suggest that modulation of different protein expression, dependent on the type of brain edema, is required for primary (pMCAO) and secondary (SH) brain injuries to attenuate brain edema and neuronal degeneration
Cherenkov radiation control via self-accelerating wave-packets
Cherenkov radiation is a ubiquitous phenomenon in nature. It describes electromagnetic radiation from a charged particle moving in a medium with a uniform velocity larger than the phase velocity of light in the same medium. Such a picture is typically adopted in the investigation of traditional Cherenkov radiation as well as its counterparts in different branches of physics, including nonlinear optics, spintronics and plasmonics. In these cases, the radiation emitted spreads along a “cone”, making it impractical for most applications. Here, we employ a self-accelerating optical pump wave-packet to demonstrate controlled shaping of one type of generalized Cherenkov radiation - dispersive waves in optical fibers. We show that, by tuning the parameters of the wave-packet, the emitted waves can be judiciously compressed and focused at desired locations, paving the way to such control in any physical system
Exome Sequencing Reveals Common and Rare Variants in F5 Associated With ACE Inhibitor and Angiotensin Receptor Blocker–Induced Angioedema
Angioedema occurring in the head and neck region is a rare and sometimes life‐threatening adverse reaction to angiotensin‐converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs). Few studies have investigated the association of common variants with this extreme reaction, but none have explored the combined influence of rare variants yet. Adjudicated cases of ACEI‐induced angioedema (ACEI‐AE) or ARB‐induced angioedema (ARB‐AE) and controls were recruited at five different centers. Sequencing of 1,066 samples (408 ACEI‐AE, ARB‐AE, and 658 controls) was performed using exome‐enriched sequence data. A common variant of the F5 gene that causes an increase in blood clotting (rs6025, p.Arg506Gln, also called factor V Leiden), was significantly associated with both ACEI‐AE and ARB‐AE (odds ratio: 2.85, 95% confidence interval (CI), 1.89–4.25). A burden test analysis of five rare missense variants in F5 was also found to be associated with ACEI‐AE or ARB‐AE, P = 2.09 × 10−3. A combined gene risk score of these variants, and the common variants rs6025 and rs6020, showed that individuals carrying at least one variant had 2.21 (95% CI, 1.49–3.27, P = 6.30 × 10−9) times the odds of having ACEI‐AE or ARB‐AE. The increased risk due to the common Leiden allele was confirmed in a genome‐wide association study from the United States. A high risk of angioedema was also observed for the rs6020 variant that is the main coagulation defect‐causing variant in black African and Asian populations. We found that deleterious missense variants in F5 are associated with an increased risk of ACEI‐AE or ARB‐AE
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