9,151 research outputs found
Characterization of a rare analphoid supernumerary marker chromosome in mosaic
Abstract publicado em: Chromosome Research. 2015;23(Suppl 1):67-8. doi:10.1007/s10577-015-9476-6Analphoid supernumerary marker chromosomes (SMCs) are a rare subclass of SMCs C-band-negative
and devoid of alpha-satellite DNA. These marker chromosomes cannot be identified unambiguously by conventional banding techniques alone being necessary to apply molecular cytogenetic methods in favour of a detailed characterization. In this work we report an analphoid SMC involving the terminal long arm of chromosome 7, in 9 years-old boy with several dysmorphic features and severe development delay.
Cytogenetic analysis revealed a mosaic karyotype with the presence of an extra SMC, de novo, in 20 %
of lymphocytes and 73 % of fibroblast cells. FISH analysis with alpha-satellite probes for all chromosomes, whole chromosome painting probe for chromosome 7, and D7S427 and TelVysion 7q probes, allowed
establishing the origin of the SMC as an analphoidmarker resulting of an invdup rearrangement of 7q36-qter region. Affimetrix CytoScan HD microarray analysis, redefined the SMC to arr[hg19] 7q35(143696249-159119707)×2~3, which correspond to a gain of 15.42 Mb and encloses 67 OMIM genes, 16 of which are associated to disease. This result, combined with detailed clinical description, will provide an important means for better genotype-phenotype correlation and a more suitable genetic counselling to the patient and his parents, despite the additional difficulty resulting from being a mosaic (expression varies in different tissues). Analphoid SMCs derived from chromosome 7 are very rare, with only three cases reported so far. With this case we hope contribute to a better understanding of this type of chromosome rearrangements which are difficult for genetic counselling
Phase transition of a two dimensional binary spreading model
We investigated the phase transition behavior of a binary spreading process
in two dimensions for different particle diffusion strengths (). We found
that cluster mean-field approximations must be considered to get
consistent singular behavior. The approximations result in a continuous
phase transition belonging to a single universality class along the phase transition line. Large scale simulations of the particle density
confirmed mean-field scaling behavior with logarithmic corrections. This is
interpreted as numerical evidence supporting that the upper critical dimension
in this model is .The pair density scales in a similar way but with an
additional logarithmic factor to the order parameter. At the D=0 endpoint of
the transition line we found DP criticality.Comment: 8 pages, 10 figure
Global fixed point proof of time-dependent density-functional theory
We reformulate and generalize the uniqueness and existence proofs of
time-dependent density-functional theory. The central idea is to restate the
fundamental one-to-one correspondence between densities and potentials as a
global fixed point question for potentials on a given time-interval. We show
that the unique fixed point, i.e. the unique potential generating a given
density, is reached as the limiting point of an iterative procedure. The
one-to-one correspondence between densities and potentials is a straightforward
result provided that the response function of the divergence of the internal
forces is bounded. The existence, i.e. the v-representability of a density, can
be proven as well provided that the operator norms of the response functions of
the members of the iterative sequence of potentials have an upper bound. The
densities under consideration have second time-derivatives that are required to
satisfy a condition slightly weaker than being square-integrable. This approach
avoids the usual restrictions of Taylor-expandability in time of the uniqueness
theorem by Runge and Gross [Phys.Rev.Lett.52, 997 (1984)] and of the existence
theorem by van Leeuwen [Phys.Rev.Lett. 82, 3863 (1999)]. Owing to its
generality, the proof not only answers basic questions in density-functional
theory but also has potential implications in other fields of physics.Comment: 4 pages, 1 figur
A Study of Two-Temperature Non-Equilibrium Ising Models: Critical Behavior and Universality
We study a class of 2D non-equilibrium Ising models based on competing
dynamics induced by contact with heat-baths at two different temperatures. We
make a comparative study of the non-equilibrium versions of Metropolis, heat
bath/Glauber and Swendsen-Wang dynamics and focus on their critical behavior in
order to understand their universality classes. We present strong evidence that
some of these dynamics have the same critical exponents and belong to the same
universality class as the equilibrium 2D Ising model. We show that the bond
version of the Swendsen-Wang update algorithm can be mapped into an equilibrium
model at an effective temperature.Comment: 12 pages of LaTeX plus 18 pages of postscript figures in a uuencoded
file (608k
Retinopathy of prematurity: A review of pathophysiology and signaling pathways
Retinopathy of prematurity (ROP) is a vasoproliferative disorder of the retina and a leading cause of visual impairment and childhood blindness worldwide. The disease is characterized by an early stage of retinal microvascular degeneration, followed by neovascularization that can lead to subsequent retinal detachment and permanent visual loss. Several factors play a key role during the different pathological stages of the disease. Oxidative and nitrosative stress and inflammatory processes are important contributors to the early stage of ROP. Nitric oxide synthase and arginase play important roles in ischemia/reperfusion-induced neurovascular degeneration. Destructive neovascularization is driven by mediators of the hypoxia-inducible factor pathway, such as vascular endothelial growth factor and metabolic factors (succinate). The extracellular matrix is involved in hypoxia-induced retinal neovascularization. Vasorepulsive molecules (semaphorin 3A) intervene preventing the revascularization of the avascular zone. This review focuses on current concepts about signaling pathways and their mediators, involved in the pathogenesis of ROP, highlighting new potentially preventive and therapeutic modalities. A better understanding of the intricate molecular mechanisms underlying the pathogenesis of ROP should allow the development of more effective and targeted therapeutic agents to reduce aberrant vasoproliferation and facilitate physiological retinal vascular development.info:eu-repo/semantics/publishedVersio
Perceived age discrimination across age in Europe: from an ageing society to a society for all ages
Ageism is recognized as a significant obstacle to older people's well-being, but age discrimination against younger people has attracted less attention. We investigate levels of perceived age discrimination across early to late adulthood, using data from the European Social Survey (ESS), collected in 29 countries (N = 56,272). We test for approximate measurement invariance across countries. We use local structural equation modeling as well as moderated nonlinear factor analysis to test for measurement invariance across age as a continuous variable. Using models that account for the moderate degree of noninvariance, we find that younger people report experiencing the highest levels of age discrimination. We also find that national context substantially affects levels of ageism experienced among older respondents. The evidence highlights that more research is needed to address ageism in youth and across the life span, not just old adulthood. It also highlights the need to consider factors that differently contribute to forms of ageism experienced by people at different life stages and ages.info:eu-repo/semantics/acceptedVersio
Magnetic field tuning of antiferromagnetic YbPt
We present measurements of the specific heat, magnetization, magnetocaloric
effect and magnetic neutron diffraction carried out on single crystals of
antiferromagnetic YbPt, where highly localized Yb moments order at
K in zero field. The antiferromagnetic order was suppressed to
by applying a field of 1.85 T in the plane.
Magnetocaloric effect measurements show that the antiferromagnetic phase
transition is always continuous for , although a pronounced step
in the magnetization is observed at the critical field in both neutron
diffraction and magnetization measurements. These steps sharpen with decreasing
temperature, but the related divergences in the magnetic susceptibility are cut
off at the lowest temperatures, where the phase line itself becomes vertical in
the field-temperature plane. As , the antiferromagnetic
transition is increasingly influenced by a quantum critical endpoint, where
ultimately vanishes in a first order phase transition.Comment: 9 pages, 6 figure
Do loyalty cards enhance loyalty in the pharmaceutical sector?
This paper aims to analyze the influence of the “Portuguese Pharmacies card” (PP card) on the pharmacies’ customers behaviour. It also intends to examine whether marketing stimuli influence consumers’ buying behavior with regard to non-prescription medicines / health and wellness product / pharmaceutical services (NP/HW/PS) and to understand if the consumer social-demographic characteristics influence purchase decisions and customers’ loyalty.
The investigation is based on the results obtained through an online survey. Exploratory descriptive analysis, based on a sample of 385 customers, is used to empirically verify the hypothesis under study. The Marketing of stimuli considered in this research include four communication tools: advertising, sales promotions, word of mouth and the sales force. According to the results obtained, the degree of influence attributed to these various communication tools in the buying decision does not differ significantly in terms of socio-demographic categories. On the other hand, the purchase volume of NP/HW/PS is significantly dependent on the influence of advertising and sales promotions in the purchase decision. Furthermore, impulse buying of NP/HW/PS is significantly dependent on the influence of advertising, promotions and WOM. We conclude that the Portuguese Pharmacies card indeed contributes to customer loyalty in the establishments where it is present. In order to meet customer expectations, a loyalty program should be adjusted over time, seeking to stimulate the satisfaction and reliance in this program.info:eu-repo/semantics/acceptedVersio
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