5,877 research outputs found
Scale Invariance and the AdS/CFT Correspondence
Using the AdS/CFT correspondence, we show that the Anti-de Sitter (AdS)
rotating (Kerr) black holes in five and seven dimensions provide us with
examples of non-trivial field theories which are scale, but not conformally
invariant. This is demonstrated by our computation of the actions and the
stress-energy tensors of the four and six dimensional field theories residing
on the boundary of these Kerr-AdS black holes spacetimes.Comment: 3 pages. LaTeX, IJMP style. Contribution to proceedings of DPF 2000,
held at Ohio State
-dimensional charged Anti-de-Sitter black holes in gravity
We present a -dimensional charged Anti-de-Sitter black hole solutions in
gravity, where and . These solutions are
characterized by flat or cylindrical horizons. The interesting feature of these
solutions is the existence of inseparable electric monopole and quadrupole
terms in the potential which share related momenta, in contrast with most of
the known charged black hole solutions in General Relativity and its
extensions. Furthermore, these solutions have curvature singularities which are
milder than those of the known charged black hole solutions in General
Relativity and Teleparallel Gravity. This feature can be shown by calculating
some invariants of curvature and torsion tensors. Furthermore, we calculate the
total energy of these black holes using the energy-momentum tensor. Finally, we
show that these charged black hole solutions violate the first law of
thermodynamics in agreement with previous results.Comment: 11 Pages, will appear in JHE
Identifying candidates for targeted gait rehabilitation: better prediction through biomechanics-informed characterization
BACKGROUND:
Walking speed has been used to predict the efficacy of gait training; however, poststroke motor impairments are heterogeneous and different biomechanical strategies may underlie the same walking speed. Identifying which individuals will respond best to a particular gait rehabilitation program using walking speed alone may thus be limited. The objective of this study was to determine if, beyond walking speed, participants' baseline ability to generate propulsive force from their paretic limbs (paretic propulsion) influences the improvements in walking speed resulting from a paretic propulsion-targeting gait intervention.
METHODS:
Twenty seven participants >6 months poststroke underwent a 12-week locomotor training program designed to target deficits in paretic propulsion through the combination of fast walking with functional electrical stimulation to the paretic ankle musculature (FastFES). The relationship between participants' baseline usual walking speed (UWSbaseline), maximum walking speed (MWSbaseline), and paretic propulsion (propbaseline) versus improvements in usual walking speed (∆UWS) and maximum walking speed (∆MWS) were evaluated in moderated regression models.
RESULTS:
UWSbaseline and MWSbaseline were, respectively, poor predictors of ΔUWS (R 2  = 0.24) and ΔMWS (R 2  = 0.01). Paretic propulsion × walking speed interactions (UWSbaseline × propbaseline and MWSbaseline × propbaseline) were observed in each regression model (R 2 s = 0.61 and 0.49 for ∆UWS and ∆MWS, respectively), revealing that slower individuals with higher utilization of the paretic limb for forward propulsion responded best to FastFES training and were the most likely to achieve clinically important differences.
CONCLUSIONS:
Characterizing participants based on both their walking speed and ability to generate paretic propulsion is a markedly better approach to predicting walking recovery following targeted gait rehabilitation than using walking speed alone
Studies on plant based dietary supplements for control of Aeromonas hydrophila infections in rainbow trout (Oncorhynchus mykiss Walbaum)
Rainbow trout (Oncorhynchus mykiss Walbaum) of average weight 18 g, were fed for
two weeks with diet supplemented with 0.5 g (= 0.5%), 1 g (= 1%) and 2 g (= 2%) 100
g-1 of lupin (Lupinus perennis), mango (Mangifera indica) and stinging nettle (Urtica
dioica), and with normal diet as controls. Following challenge with Aeromonas
hydrophila, there was a reduction in mortality compared with the controls.
Furthermore, the fish, which were fed with dietary supplements, recorded enhanced
haematological and immunological parameters including phagocytic, respiratory burst,
lysozyme, bactericidal, complement, myloperoxidase and antiprotease activities, and
total protein, compared to the controls. Feeding for 2 months with 1% and 2% of the
dietary supplements led to an increase in growth performance, body composition,
digestive enzyme (total proteases, amylase, lipase and pepsin), total protein and glucose
compared to controls, whereas there was not any effect on kidney or liver function. The
expression of IL-1ß, IL-8 and TGF- ß1 in head kidney of rainbow trout fed for 2 months
was upregulated after feeding with 1% lupin and 1% stinging nettle. In contrast, there
was not any significant effect following feeding with mango
Underdetermined blind source separation based on Fuzzy C-Means and Semi-Nonnegative Matrix Factorization
Conventional blind source separation is based on over-determined with more sensors than sources but the underdetermined is a challenging case and more convenient to actual situation. Non-negative Matrix Factorization (NMF) has been widely applied to Blind Source Separation (BSS) problems. However, the separation results are sensitive to the initialization of parameters of NMF. Avoiding the subjectivity of choosing parameters, we used the Fuzzy C-Means (FCM) clustering technique to estimate the mixing matrix and to reduce the requirement for sparsity. Also, decreasing the constraints is regarded in this paper by using Semi-NMF. In this paper we propose a new two-step algorithm in order to solve the underdetermined blind source separation. We show how to combine the FCM clustering technique with the gradient-based NMF with the multi-layer technique. The simulation results show that our proposed algorithm can separate the source signals with high signal-to-noise ratio and quite low cost time compared with some algorithms
Novel signaling pathways in pulmonary arterial hypertension (2015 Grover Conference Series)
The proliferative endothelial and smooth muscle cell phenotype, inflammation, and pulmonary vascular remodeling are prominent features of pulmonary arterial hypertension (PAH). Mutations in bone morphogenetic protein type 2 receptor (BMPR2) have been identified as the most common genetic cause of PAH and females with BMPR2 mutations are 2.5 times as likely to develop heritable forms of PAH than males. Higher levels of estrogen have also been observed in males with PAH, implicating sex hormones in PAH pathogenesis. Recently, the estrogen metabolite 16α-OHE1 (hydroxyestrone) was implicated in the regulation of miR29, a microRNA involved in modulating energy metabolism. In females, decreased miR96 enhances serotonin’s effect by upregulating the 5-hydroxytryptamine 1B (5HT1B) receptor. Because PAH is characterized as a quasi-malignant disease, likely due to BMPR2 loss of function, altered signaling pathways that sustain this cancer-like phenotype are being explored. Extracellular signal–regulated kinases 1 and 2 and p38 mitogen-activated protein kinases (MAPKs) play a critical role in proliferation and cell motility, and dysregulated MAPK signaling is observed in various experimental models of PAH. Wnt signaling pathways preserve pulmonary vascular homeostasis, and dysregulation of this pathway could contribute to limited vascular regeneration in response to injury. In this review, we take a closer look at sex, sex hormones, and the interplay between sex hormones and microRNA regulation. We also focus on MAPK and Wnt signaling pathways in the emergence of a proproliferative, antiapoptotic endothelial phenotype, which then orchestrates an angioproliferative process of vascular remodeling, with the hope of developing novel therapies that could reverse the phenotype
The integration of input filters in electrical drives
PhD ThesisThe integration of passive components such as inductors and capacitors has gained significant
popularity in integrated drive research, and future power electronics systems will require more
integrated and standardised packages. These give rise to better power density and improved
performance. However, packaging techniques and passive components have been considered a
technological barrier which is limiting advances in power electronics. The focus on size
reduction should be turned towards the passive components, such as converter chokes, DC-link
capacitors and electromagnetic interference (EMI) filters, and achieving greater power density
depends on innovative integration concepts, flexibility in structures and extended operating
temperature ranges while system integration and modularity are not mutually exclusive.
This research considers the possibility of integrating input power filter components into electric
machines. Particular attention is paid to the integration of electromagnetic line filter inductors
to give better utilisation of the motor volume and envelope. This can be achieved by sharing
the machine’s magnetic circuit. An LCL line filter has been chosen to be integrated with a gridconnected permanent magnet synchronous machine. Machines have been proposed in this study
for low speed (3000 RPM) and high speed (25000 RPM) operation. The two machines have
similar dimensions, but the low-speed machine is less challenging in terms of losses and filter
integration, so attention is directed more to the high-speed machine. Both are supplied with
low- and high-power drives at power ratings of 4.5 kW and 38 kW respectively.
Several novel techniques have been investigated to integrate filter inductors into the electrical
machines to produce a single mechanically packaged unit without significant increases in size
and losses. Different approaches have been simulated using finite element analysis (FEA) to
assess the effectiveness of the integration of passives within the machine structure. Each design
has been iteratively optimised to determine the best mass of copper and core for the integrated
filter inductors, targeting parity in power density when compared to traditional separate
packages. The research demonstrates that an approach utilising a double-slot stator machine
(named the integrated double slot (IDS) machine) with input filters wound into the outermost
slots is the most appropriate choice in terms of achieving higher power density.
The integrated filter inductors mimic the electromagnetic behaviour of the discrete industrially
packaged inductors but with a volume reduction of 87.6%. A prototype of the IDS machine
design of a 38 kW, 25000 RPM, including filter inductors was manufactured and testedthe General Electricity Company of Libya
(GECOL), the Engineering and Physical Sciences Research Council (EPSRC), and the
Engineering Doctorate scheme at Newcastle University
Reconsiderando el significado de Hogar en la Rehabilitación: hacia una ciudad histórica sostenible
Despite the significant literature about the meaning of home and the scholars’ research concerning the home environment, the concept of home didn’t filter into the rehabilitation process. The conservation theory and the rehabilitation methodology are still concentrating on the material aspects of the built environment and ignoring the immaterial aspects and meanings.
In view of that the dwellings are not only artifacts but they are a livable example of the social structure and behavioral patterns. Understanding the dwellers relationship with their dwellings will be helpful in establishing a connection between the rehabilitation of the historical domestic architecture and the concept of home. This requires reconsidering the theoretical frame work of the rehabilitation process so as to be able to recognize the change in the historical house’s spatial structure and order and to link them to the social structure and pattern of use.A pesar de la gran cantidad de literatura sobre el significado del hogar y las investigaciones hechas por académicos sobre el ambiente del hogar, el concepto de hogar no se filtró en el proceso de rehabilitación. La teorÃa de la conservación y la metodologÃa de rehabilitación siguen concentrándose en los aspectos materiales del ambiente construido e ignoran los aspectos inmateriales.
Tomando en cuenta que las viviendas no son sólo objetos, sino ejemplos de estructuras sociales, y patrones de conducta, el entendimiento de la relación entre habitantes y sus viviendas será de utilidad para establecer una conexión entre la rehabilitación de la arquitectura doméstica histórica y el concepto del hogar. Para ello es necesario reconsiderar el marco de trabajo teórico del proceso de rehabilitación con el fin de ser capaz de reconocer el cambio en la estructura espacial del hogar histórico y el orden, y vincularlos a la estructura social
Higher Dimensional Taub-NUTs and Taub-Bolts in Einstein-Maxwell Gravity
We present a class of higher dimensional solutions to Einstein-Maxwell
equations in d-dimensions. These solutions are asymptotically locally flat,
de-Sitter, or anti-de Sitter space-times. The solutions we obtained depend on
two extra parameters other than the mass and the nut charge. These two
parameters are the electric charge, q and the electric potential at infinity,
V, which has a non-trivial contribution. We Analyze the conditions one can
impose to obtain Taub-Nut or Taub-Bolt space-times, including the
four-dimensional case. We found that in the nut case these conditions coincide
with that coming from the regularity of the one-form potential at the horizon.
Furthermore, the mass parameter for the higher dimensional solutions depends on
the nut charge and the electric charge or the potential at infinity.Comment: 11 pages, LaTe
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