7,827 research outputs found
On phantom thermodynamics with negative temperature
We discuss the thermodynamic properties of the Friedmann-Robertson-Walker
universe with dark energy fluids labelled by . Using the
integrability condition, we show that the phantom phase of can still be
thermodynamically allowed even when the temperature takes on negative values
because in that case, there exists at least a condition of keeping physical
values for and Comment: 8 pages, 1figure, title changed, version to appear in PL
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Diagnostic assay for late-onset Alzheimer's disease
The present invention provides a quantitative assay for early diagnosis of late-onset sporadic AD in living individuals using peripheral tissue biopsy. The assay may also be used for post-mortem diagnosis. More particularly, the invention relates to detecting changes in the level of mitochondrial cytochrome oxidase activity for diagnosing and monitoring AD.Board of Regents, University of Texas Syste
PROVIDE VEHICLE MICROPHONE FOR A THIRD-PARTY APPLICATION
When a user is driving a vehicle (e.g., automobile, motorcycle, a bus, a recreational vehicle (RV), a semi-trailer truck, a tractor or other type of farm equipment, a train, a plane, a helicopter, etc.), a computing device (e.g., a smartphone, a tablet computer, smartglasses, a smartwatch, a portable gaming system, a laptop computer, etc.) may be located in the userâs pocket, purse, etc., potentially worsening the quality of the audio data recorded by a microphone built into the computing device. To address this issue, the computing device may enable applications installed at the computing device to use microphones built into the vehicle (which potentially records higher quality audio data than microphones built into the computing device). An operating system executing at the computing device may provide a library (referred to herein as a âvoice templateâ) accessible by the applications installed at the computing device. The applications may request access to the vehicle microphones using the voice template and may receive audio data from the vehicle microphones using the voice template. As a result, applications executing at the computing device may receive higher quality audio data, which may improve the accuracy and reliability of voice input processing
Low-level light therapy of the eye and brain
Abstract: Low-level light therapy (LLLT) using red to near-infrared light energy has gained attention in recent years as a new scientific approach with therapeutic applications in ophthalmology, neurology, and psychiatry. The ongoing therapeutic revolution spearheaded by LLLT is largely propelled by progress in the basic science fields of photobiology and bioenergetics. This paper describes the mechanisms of action of LLLT at the molecular, cellular, and nervous tissue levels. Photoneuromodulation of cytochrome oxidase activity is the most important primary mechanism of action of LLLT. Cytochrome oxidase is the primary photoacceptor of light in the red to near-infrared region of the electromagnetic spectrum. It is also a key mitochondrial enzyme for cellular bioenergetics, especially for nerve cells in the retina and the brain. Evidence shows that LLLT can secondarily enhance neural metabolism by regulating mitochondrial function, intraneuronal signaling systems, and redox states. Current knowledge about LLLT dosimetry relevant for its hormetic effects on nervous tissue, including noninvasive in vivo retinal and transcranial effects, is also presented. Recent research is reviewed that supports LLLT potential benefits in retinal disease, stroke, neurotrauma, neurodegeneration, and memory and mood disorders. Since mitochondrial dysfunction plays a key role in neurodegeneration, LLLT has potential significant applications against retinal and brain damage by counteracting the consequences of mitochondrial failure. Upon transcranial delivery in vivo, LLLT induces brain metabolic and antioxidant beneficial effects, as measured by increases in cytochrome oxidase and superoxide dismutase activities. Increases in cerebral blood flow and cognitive functions induced by LLLT have also been observed in humans. Importantly, LLLT given at energy densities that exert beneficial effects does not induce adverse effects. This highlights the value of LLLT as a novel paradigm to treat visual, neurological, and psychological conditions, and supports that neuronal energy metabolism could constitute a major target for neurotherapeutics of the eye and brain
Transition Redshift: New Kinematic Constraints from Supernovae
The transition redshift (deceleration/acceleration) is discussed by expanding
the deceleration parameter to first order around its present value. A detailed
study is carried out by considering two different parameterizations: and , and the associated free parameters () are constrained by 3 different supernova samples. The previous analysis
by Riess {\it{et al.}} [ApJ 607, 665, 2004] using the first expansion is
slightly improved and confirmed in light of their recent data ({\emph{Gold}}07
sample). However, by fitting the model with the Supernova Legacy Survey (SNLS)
type Ia sample we find that the best fit to the redshift transition is instead of as derived by the High-z Supernovae Search
(HZSNS) team. This result based in the SNLS sample is also in good agreement
with the Davis {\it{et al.}} sample, ().
Such results are in line with some independent analyzes and accommodates more
easily the concordance flat model (CDM). For both parameterizations,
the three SNe type Ia samples considered favor recent acceleration and past
deceleration with a high degree of statistical confidence level. All the
kinematic results presented here depend neither on the validity of general
relativity nor the matter-energy contents of the Universe.Comment: 19 pages, 15 figures, 1 table, revised version accepted for
publication in MNRA
Litter Environment Affects Behavior and Brain Metabolic Activity of Adult Knockout Mice
In mammals, the formative environment for social and anxiety-related behaviors is the family unit; in the case of rodents, this is the litter and the mother-young bond. A deciding factor in this environment is the sex ratio of the litter and, in the case of mice lacking functional copies of gene(s), the ratio of the various genotypes in the litter. Both Sex and Genotype ratios of the litter affect the nature and quality of the individual's behavior later in adulthood, as well as metabolic activity in brain nuclei that underlie these behaviors. Mice were raised in litters reconstituted shortly after to birth to control for sex ratio and genotype ratio (wild type pups versus pups lacking a functional estrogen receptor α). In both males and females, the Sex and Genotype of siblings in the litter affected aggressive behaviors as well as patterns of metabolic activity in limbic nuclei in the social behavior network later in adulthood. Further, this pattern in males varied depending upon the Genotype of their brothers and sisters. Principal Components Analysis revealed two components comprised of several amygdalar and hypothalamic nuclei; the VMH showed strong correlations in both clusters, suggesting its pivotal nature in the organization of two neural networks
Portuguese Version of the Ageing Attitudes Questionnaire (AAQ): Validation of the Psychometric Properties
The Ageing Attitudes QuestionnaireâAAQ was validated for the Portuguese population
to understand the importance of attitudes towards old age and their impact on the subjective wellbeing of older adults. A sample of 400 subjects (from 18 to 93 years) answered a socio-demographic
questionnaire, and the AAQ, composed of three subscales (psychosocial losses, physical change, and
psychological growth). The CFA confirmed the tri-factorial structure with very good adjustment
of the model to the data, with the Cronbach alpha of the total scale scoring 0.84 and ranging from
0.65 to 0.77 for each factor. A total of nine items were omitted for poor factor loadings (<0.50),
namely in factor 1 items 9-17-20, in factor 2 items 7 and 24 and, finally, in factor 3 we omitted items
4-18-19-21. Notwithstanding, three items below the criteria were maintained, as they conceptually
fit into the factor. Of the final 15 AAQ items, 5 belong to the Psychosocial Loss Factor, 6 to Physical
Change Factor, and 4 to Psychosocial Growth Factor. This tree factor model explained 50.1% of the
total variance. In conclusion, this study supports that AAQ has acceptable validity, confirming the
composite reliability and the discriminant validity, but not the convergent validity. Through multigroup analysis, the invariance of the scale was confirmed. This validation is of pivotal importance
once it allows measuring attitudes towards ageing in the Portuguese population, thus facilitating the
prevention of ageism and the promotion of well-being across the lifespan.info:eu-repo/semantics/publishedVersio
Thermodynamics and dark energy
A significant observational effort has been directed to unveil the nature of
the so-called dark energy. However, given the large number of theoretical
possibilities, it is possible that such a task cannot be performed on the basis
only of the observational data. In this article we discuss some thermodynamic
properties of this energy component by assuming that its constituents are
massless quanta with a general time-dependent equation-of-state parameter
, where and are
constants and may assume different forms. We show that very restrictive
bounds can be placed on the - space when current observational data
are combined with the thermodynamic constraints derived.Comment: 5 pages, 3 figures, LaTe
Progmosis:evaluating risky individual behavior during epidemics using mobile network data
The possibility to analyze, quantify and forecast epidemic outbreaks is fundamental when devising effective disease containment strategies. Policy makers are faced with the intricate task of drafting realistically implementable policies that strike a balance between risk management and cost. Two major techniques policy makers have at their disposal are: epidemic modeling and contact tracing. Models are used to forecast the evolution of the epidemic both globally and regionally, while contact tracing is used to reconstruct the chain of people who have been potentially infected, so that they can be tested, isolated and treated immediately. However, both techniques might provide limited information, especially during an already advanced crisis when the need for action is urgent. In this paper we propose an alternative approach that goes beyond epidemic modeling and contact tracing, and leverages behavioral data generated by mobile carrier networks to evaluate contagion risk on a per-user basis. The individual risk represents the loss incurred by not isolating or treating a specific person, both in terms of how likely it is for this person to spread the disease as well as how many secondary infections it will cause. To this aim, we develop a model, named Progmosis, which quantifies this risk based on movement and regional aggregated statistics about infection rates. We develop and release an open-source tool that calculates this risk based on cellular network events. We simulate a realistic epidemic scenarios, based on an Ebola virus outbreak; we find that gradually restricting the mobility of a subset of individuals reduces the number of infected people after 30 days by 24%
Integral Menger curvature for surfaces
We develop the concept of integral Menger curvature for a large class of
nonsmooth surfaces. We prove uniform Ahlfors regularity and a
-a-priori bound for surfaces for which this functional is
finite. In fact, it turns out that there is an explicit length scale
which depends only on an upper bound for the integral Menger curvature
and the integrability exponent , and \emph{not} on the surface
itself; below that scale, each surface with energy smaller than
looks like a nearly flat disc with the amount of bending controlled by the
(local) -energy. Moreover, integral Menger curvature can be defined a
priori for surfaces with self-intersections or branch points; we prove that a
posteriori all such singularities are excluded for surfaces with finite
integral Menger curvature. By means of slicing and iterative arguments we
bootstrap the H\"{o}lder exponent up to the optimal one,
, thus establishing a new geometric `Morrey-Sobolev' imbedding
theorem.
As two of the various possible variational applications we prove the
existence of surfaces in given isotopy classes minimizing integral Menger
curvature with a uniform bound on area, and of area minimizing surfaces
subjected to a uniform bound on integral Menger curvature.Comment: 64 pages, 7 figures. Submitted. Version 2: extended comments on the
relation to Lerman's and Whitehouse's work on Menger curvature
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