989 research outputs found
Socioeconomic Inequalities in Mortality Rates in Old Age in the World Health Organization Europe Region
Socioeconomic adversity is among the foremost fundamental causes of human suffering, and this is no less true in old age. Recent reports on socioeconomic inequalities in mortality rate in old age suggest that a low socioeconomic position continues to increase the risk of death even among the oldest old. We aimed to examine the evidence for socioeconomic mortality rate inequalities in old age, including information about associations with various indicators of socioeconomic position and for various geographic locations within the World Health Organization Region for Europe. The articles included in this review leave no doubt that inequalities in mortality rate by socioeconomic position persist into the oldest ages for both men and women in all countries for which information is available, although the relative risk measures observed were rarely higher than 2.00. Still, the available evidence base is heavily biased geographically, inasmuch as it is based largely on national studies from Nordic and Western European countries and local studies from urban areas in Southern Europe. This bias will hamper the design of European-wide policies to reduce inequalities in mortality rate. We call for a continuous update of the empiric evidence on socioeconomic inequalities in mortality rate
Wave-number locking in spatially forced pattern-forming systems
Abstract -We use the Swift-Hohenberg model and normal-form equations to study wave-number locking in two-dimensional systems as a result of one-dimensional spatially periodic weak forcing. The freedom of the system to respond in a direction transverse to the forcing leads to wavenumber locking in a wide range of forcing wave-numbers, even for weak forcing, unlike the locking in a set of narrow Arnold tongues in one-dimensional systems. Multi-stability ranges of stripe, rectangular, and oblique patterns produce a variety of resonant patterns. The results shed new light on rehabilitation practices of banded vegetation in drylands. Copyright c EPLA, 2008 Frequency locking phenomena in temporally forced oscillators are well understood; a forced oscillator can adjust its frequency of oscillation to a rational fraction of the forcing frequency The spatial counterpart of frequency locking, wavenumber locking, is less well understood. Although much work has been devoted to pattern-forming systems that are subjected to spatially periodic forcing In this letter we analyze wave-number locking phenomena associated with a two-dimensional response to a one-dimensional forcing. We are interested in universal aspects of wave-number locking and therefore base our study on normal-form equations. We derive these equations using a periodically forced Swift-Hohenberg (SH) equation, which helps us motivate the problem and test our analysis using direct numerical solutions. The specific equation we consider is In this equation ε is the distance from the instability point of the unforced zero state to a stationary pattern with a wave-number k 0 ∼ O(1), k f is the forcing wave-number, γ is the intensity of multiplicative forcing and α is the intensity of additive forcing. In the absence of forcing (α = γ = 0) the unstable zero state u = 0 evolves towards a stripe pattern with wavenumber k 0 , the pattern that minimizes the Lyapunov function of the SH equation (se
The effect of signal acquisition and processing choices on ApEn values: Towards a “gold standard” for distinguishing effort levels from isometric force records
Approximate Entropy (ApEn) is frequently used to identify changes in the complexity of isometric force records with ageing and disease. Different signal acquisition and processing parameters have been used, making comparison or confirmation of results difficult. This study determined the effect of sampling and parameter choices by examining changes in ApEn values across a range of submaximal isometric contractions of the First Dorsal Interosseus. Reducing the sample rate by decimation changed both the value and pattern of ApEn values dramatically. The pattern of ApEn values across the range of effort levels was not sensitive to the filter cut-off frequency, or the criterion used to extract the section of data for analysis. The complexity increased with increasing effort levels using a fixed ‘r’ value (which accounts for measurement noise) but decreased with increasing effort level when ‘r’ was set to 0.1 of the standard deviation of force. It is recommended isometric force records are sampled at frequencies >200 Hz, template length (‘m’) is set to 2, and 'r' set to measurement system noise or 0.1 SD depending on physiological process to be distinguished. It is demonstrated that changes in ApEn across effort levels are related to changes in force gradation strategy
SOX17 is a critical specifier of human primordial germ cell fate.
Specification of primordial germ cells (PGCs) marks the beginning of the totipotent state. However, without a tractable experimental model, the mechanism of human PGC (hPGC) specification remains unclear. Here, we demonstrate specification of hPGC-like cells (hPGCLCs) from germline competent pluripotent stem cells. The characteristics of hPGCLCs are consistent with the embryonic hPGCs and a germline seminoma that share a CD38 cell-surface marker, which collectively defines likely progression of the early human germline. Remarkably, SOX17 is the key regulator of hPGC-like fate, whereas BLIMP1 represses endodermal and other somatic genes during specification of hPGCLCs. Notable mechanistic differences between mouse and human PGC specification could be attributed to their divergent embryonic development and pluripotent states, which might affect other early cell-fate decisions. We have established a foundation for future studies on resetting of the epigenome in hPGCLCs and hPGCs for totipotency and the transmission of genetic and epigenetic information.We thank Rick Livesey and his lab for help with the culture of hESCs; Sohei Kitazawa
and Janet Shipley for the TCam-2 cells; Nigel Miller and Andy Riddell
for cell sorting, Roger Barker, Xiaoling He, and Pam Tyers for collection of human
embryos; and Charles Bradshaw for help with bioinformatics. We thank
members of the Surani and Hanna labs for important discussions and technical
help. N.I. is supported by Grant-in-Aid for fellows of the JSPS and by BIRAX
(the Britain Israel Research and Academic Exchange Partnership) initiative,
who provided a project grant to J.H.H. and M.A.S. J.H.H. is supported by Ilana
and Pascal Mantoux, the Kimmel Award, ERC (StG-2011-281906), Helmsley
Charitable Trust, ISF (Bikura, Morasha, ICORE), ICRF, the Abisch Frenkel
Foundation, the Fritz Thyssen Stiftung, Erica and Robert Drake, Benoziyo
Endowment fund, and the Flight Attendant Medical Research Institute
(FAMRI). J.H.H. is a New York Stem Cell Foundation Robertson Investigator.
W.C.C.T. is supported by Croucher Foundation and Cambridge Trust;
M.A.S. is supported by HFSP and a Wellcome Trust Investigator Award.This is the final version of the article, originally published in Cell, Volume 160, Issues 1-2, p253–268, 15 January 2015, doi: 10.1016/j.cell.2014.12.01
Learning Behavioural Context
The original publication is available at www.springerlink.co
Microscope and microâ camera assessment of Schneiderian membrane perforation via transcrestal sinus floor elevation: A randomized ex vivo study
ObjectiveWe sought to assess the effectiveness of using a microscope and nonâ invasive camera for assessing sinus membrane perforations during transcrestal sinus floor elevation (TSFE).Materials and methodsFive fresh human cadaver heads corresponding to eight maxillary sinuses (six bilateral and two unilateral) underwent 4 TSFEs per sinus (a total of 32 single site elevations). Each elevation was randomly assigned to receive a three or six mm membrane elevation height (MEH). A microscope and microâ camera were used to assess the sinus membrane perforation. Afterwards, radiological and clinical membrane perforation assessments were performed. The statistical analysis results are expressed using the means, standard deviations, range values of the residual ridge height (RRH), residual ridge width (RRW), sinus membrane thickness (SMT) and incidence of perforation (IoP). Generalized linear methods were used to test for the correlation of RRH and MEH to the microscope and microâ camera perforation assessments and the correlation of microscope and microâ camera assessments with the postâ operative CBCT and crestal liquid evaluation.ResultsThe cumulative percentage of IoP was 40.62%, (23.07% with 3 mm MEH, and 76.92% with 6 mm MEH, p < 0.05). The perforation assessed using either the microscope or microâ camera coincided with the postâ operative CBCT and crestal liquid assessment in 87.55% sites. No significant correlation was found between the microscope or microâ camera assessments with RRH or MEH.ConclusionApplication of a microscope and microâ camera during transcrestal sinus floor elevation may allow the detection of the integrity of the Schneiderian membrane with greater than 85% accuracy in this ex vivo model.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149727/1/clr13453.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149727/2/clr13453_am.pd
Patchiness and Demographic Noise in Three Ecological Examples
Understanding the causes and effects of spatial aggregation is one of the
most fundamental problems in ecology. Aggregation is an emergent phenomenon
arising from the interactions between the individuals of the population, able
to sense only -at most- local densities of their cohorts. Thus, taking into
account the individual-level interactions and fluctuations is essential to
reach a correct description of the population. Classic deterministic equations
are suitable to describe some aspects of the population, but leave out features
related to the stochasticity inherent to the discreteness of the individuals.
Stochastic equations for the population do account for these
fluctuation-generated effects by means of demographic noise terms but, owing to
their complexity, they can be difficult (or, at times, impossible) to deal
with. Even when they can be written in a simple form, they are still difficult
to numerically integrate due to the presence of the "square-root" intrinsic
noise. In this paper, we discuss a simple way to add the effect of demographic
stochasticity to three classic, deterministic ecological examples where
aggregation plays an important role. We study the resulting equations using a
recently-introduced integration scheme especially devised to integrate
numerically stochastic equations with demographic noise. Aimed at scrutinizing
the ability of these stochastic examples to show aggregation, we find that the
three systems not only show patchy configurations, but also undergo a phase
transition belonging to the directed percolation universality class.Comment: 20 pages, 5 figures. To appear in J. Stat. Phy
Vibrational Spectra of a Mechanosensitive Channel
We report the simulated vibrational spectra of a mechanosensitive membrane channel in different gating states. Our results show that while linear absorption is insensitive to structural differences, linear dichroism and sum-frequency generation spectroscopies are sensitive to the orientation of the transmembrane helices, which is changing during the opening process. Linear dichroism cannot distinguish an intermediate structure from the closed structure, but sum-frequency generation can. In addition, we find that two-dimensional infrared spectroscopy can be used to distinguish all three investigated gating states of the mechanosensitive membrane channel.
A Sexual Shift Induced by Silencing of a Single Insulin-Like Gene in Crayfish: Ovarian Upregulation and Testicular Degeneration
In sequential hermaphrodites, intersexuality occurs naturally, usually as a transition state during sexual re-differentiation processes. In crustaceans, male sexual differentiation is controlled by the male-specific androgenic gland (AG). An AG-specific insulin-like gene, previously identified in the red-claw crayfish Cherax quadricarinatus (designated Cq-IAG), was found in this study to be the prominent transcript in an AG cDNA subtractive library. In C. quadricarinatus, sexual plasticity is exhibited by intersex individuals in the form of an active male reproductive system and male secondary sex characters, along with a constantly arrested ovary. This intersexuality was exploited to follow changes caused by single gene silencing, accomplished via dsRNA injection. Cq-IAG silencing induced dramatic sex-related alterations, including male feature feminization, a reduction in sperm production, extensive testicular degeneration, expression of the vitellogenin gene, and accumulation of yolk proteins in the developing oocytes. Upon silencing of the gene, AG cells hypertrophied, possibly to compensate for low hormone levels, as reflected in the poor production of the insulin-like hormone (and revealed by immunohistochemistry). These results demonstrate both the functionality of Cq-IAG as an androgenic hormone-encoding gene and the dependence of male gonad viability on the Cq-IAG product. This study is the first to provide evidence that silencing an insulin-like gene in intersex C. quadricarinatus feminizes male-related phenotypes. These findings, moreover, contribute to the understanding of the regulation of sexual shifts, whether naturally occurring in sequential hermaphrodites or abnormally induced by endocrine disruptors found in the environment, and offer insight into an unusual gender-related link to the evolution of insulins
Predictability of oppositional defiant disorder and symptom dimensions in children and adolescents with ADHD combined type
Background Oppositional defiant disorder (ODD) is frequently co-occurring with attention deficit hyperactivity disorder (ADHD) in children and adolescents. Because ODD is a precursor of later conduct disorder (CD) and affective disorders, early diagnostic identification is warranted. Furthermore, the predictability of three recently confirmed ODD dimensions (ODD-irritable, ODD-headstrong and ODD-hurtful) may assist clinical decision making. Method Receiver-operating characteristic (ROC) analysis was used in order to test the diagnostic accuracy of the Conners' Parent Rating Scale revised (CPRS-R) and the parent version of the Strength and Difficulties Questionnaire (PSDQ) in the prediction of ODD in a transnational sample of 1093 subjects aged 5-17 years from the International Multicentre ADHD Genetics study. In a second step, the prediction of three ODD dimensions by the same parent rating scales was assessed by backward linear regression analyses. Results ROC analyses showed adequate diagnostic accuracy of the CPRS-R and the PSDQ in predicting ODD in this ADHD sample. Furthermore, the three-dimensional structure of ODD was confirmed by confirmatory factor analysis and the CPRS-R emotional lability scale significantly predicted the ODD irritable dimension. Conclusions The PSDQ and the CPRS-R are both suitable screening instruments in the identification of ODD. The emotional lability scale of the CPRS-R is an adequate predictor of irritability in youth referred for ADH
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