673 research outputs found
Projections of U.S. Edentulism Prevalence Following 5 Decades of Decline
After decades of decline in prevalence of complete tooth loss (edentulism), the trend continues to be misinterpreted, producing flawed projections and misdirected health goals. We investigated population trends in edentulism among U.S. adults aged ≥15 yr by creating time-series data from 5 national cross-sectional health surveys: 1957-1958 (n ≈ 100,000 adults), 1971-1975 (n = 14,655 adults), 1988-1998 (n = 18,011 adults), 1999-2002 (n = 12,336 adults), and 2009-2012 (n = 10,522 adults). Birth cohort analysis was used to isolate age and cohort effects. Geographic and sociodemographic variation in prevalence was investigated with a sixth U.S. survey of 432,519 adults conducted in 2010. Prevalence through 2050 was projected with age-cohort regression models using Monte-Carlo simulation of prediction intervals. Across the 5-decade observation period, edentulism prevalence declined from 18.9% in 1957-1958 (95% confidence limits: 18.4%, 19.4%) to 4.9% in 2009-2012 (95% confidence limits: 4.0%, 5.8%). The most influential determinant of the decline was the passing of generations born before the 1940s, whose rate of edentulism incidence (5%-6% per decade of age) far exceeded later cohorts (1%-3% per decade of age). High-income households experienced a greater relative decline, although a smaller absolute decline, than low-income households. By 2010, edentulism was a rare condition in high-income households, and it had contracted geographically to states with disproportionately high poverty. With the passing of generations born in the mid-20th century, the rate of decline in edentulism is projected to slow, reaching 2.6% (95% prediction limits: 2.1%, 3.1%) by 2050. The continuing decline will be offset only partially by population growth and population aging such that the predicted number of edentulous people in 2050 (8.6 million; 95% prediction limits: 6.8 million, 10.3 million) will be 30% lower than the 12.2 million edentulous people in 2010
A controlled evaluation of an enhanced self-directed behavioural family intervention for parents of children with conduct problems in rural and remote areas.
Few studies have examined the impact of parenting interventions for families in rural and isolated areas who have children with conduct problems, where-access to professional services can be difficult. The present investigation compared the effects of three conditions, two levels of self-directed behavioral family intervention: an enhanced self-directed program that combined a self-help program using written materials and a weekly telephone consultation (ESD), a self-help program (SD) and a waitlist control group (WL). At postintervention the ESD group reported significantly lower levels of disruptive behaviour, and lower levels of dysfunctional parenting than the SD and WL controls, and higher levels of consumer satisfaction. At 6 months follow-up the main effects for the ESD group had been maintained. The SD group continued to evidence improvement from postintervention to follow-up such that 65% of children in the ESD condition and 57% of children in the SD condition showed clinical reliable change on measures of disruptive behaviour. Implications of findings and directions for future research are discussed
Quantum central limit theorem for continuous-time quantum walks on odd graphs in quantum probability theory
The method of the quantum probability theory only requires simple structural
data of graph and allows us to avoid a heavy combinational argument often
necessary to obtain full description of spectrum of the adjacency matrix. In
the present paper, by using the idea of calculation of the probability
amplitudes for continuous-time quantum walk in terms of the quantum probability
theory, we investigate quantum central limit theorem for continuous-time
quantum walks on odd graphs.Comment: 19 page, 1 figure
Are long gamma-ray bursts biased tracers of star formation? Clues from the host galaxies of the Swift/BAT6 complete sample of bright LGRBs. :III. Stellar masses, star formation rates, and metallicities at z > 1
(Abridged) Long gamma-ray bursts (LGRB) have been suggested as promising
tracers of star formation owing to their association with the core-collapse of
massive stars. The goal of this work is to characterise the population of host
galaxies of LGRBs at 1 < z < 2, investigate the conditions in which LGRBs form
at these redshifts and assess their use as tracers of star formation. We
perform a spectro-photometric analysis to determine the stellar mass, star
formation rate, specific star formation rate and metallicity of the complete,
unbiased host galaxy sample of the Swift/BAT6 LGRB sample at 1 < z < 2. We
compare the distribution of these properties to the ones of typical
star-forming galaxies from the MOSDEF and COSMOS2015 Ultra Deep surveys, within
the same redshift range. We find that, similarly to z < 1, LGRBs do not
directly trace star formation at 1 < z < 2, and they tend to avoid high-mass,
high-metallicity host galaxies. We also find evidence for an enhanced fraction
of starbursts among the LGRB host sample with respect to the star-forming
population of galaxies. Nonetheless we demonstrate that the driving factor
ruling the LGRB efficiency is metallicity. The LGRB host distributions can be
reconciled with the ones expected from galaxy surveys by imposing a metallicity
upper limit of 12+logOH ~ 8.55. Metallicity rules the LGRB production
efficiency, which is stifled at Z > 0.7 Zsun. Under this hypothesis we can
expect LGRBs to trace star formation at z > 3, once the bulk of the star
forming galaxy population are characterised by metallicities below this limit.
The moderately high metallicity threshold found is in agreement with the
conditions necessary to rapidly produce a fast-rotating Wolf-Rayet star a in
close binary system, and could be accommodated by single star models under
chemically homogeneous mixing with very rapid rotation and weak magnetic
coupling.Comment: 19 pages, 17 figures, accepted for publication in Astronomy &
Astrophysic
Topological Orthoalgebras
We define topological orthoalgebras (TOAs) and study their properties. While
every topological orthomodular lattice is a TOA, the lattice of projections of
a Hilbert space is an example of a lattice-ordered TOA that is not a toplogical
lattice. On the other hand, we show that every compact Boolean TOA is a
topological Boolean algebra. We also show that a compact TOA in which 0 is an
isolated point is atomic and of finite height. We identify and study a
particularly tractable class of TOAs, which we call {\em stably ordered}: those
in which the upper-set generated by an open set is open. This includes all
topological OMLs, and also the projection lattices of Hilbert spaces. Finally,
we obtain a topological version of the Foulis-Randall representation theory for
stably ordered TOAsComment: 16 pp, LaTex. Minor changes and corrections in sections 1; more
substantial corrections in section
Maatschappelijke initiatieven voor natuur en biodiversiteit : een schets van de reikwijdte en ecologische effecten en potenties van maatschappelijke initiatieven voor natuur in feiten en cijfers
Voor de Balans van de Leefomgeving willen we weten welke feiten en cijfers bekend zijn over maatschappelijke activiteiten, initiatieven en functiecombinaties voor natuur en biodiversiteit en wat de bijdrage hiervan is om de biodiversiteit te verbeteren. In dit onderzoek hebben we gegevens verzameld in de beschikbare literatuur en online bronnen. Uit de verzamelde feiten en cijfers blijkt dat het merendeel van de burgers betrokken zijn bij natuur en dat op onderdelen de betrokkenheid van burgers maar ook van bedrijven toeneemt. De meeste groene burgerinitiatieven zijn gericht op beleefbaar groen maar soms worden ook belangrijke natuurwaarden gerealiseerd die aansluiten bij internationale biodiversiteitsdoelstellingen. Burgers spelen daarnaast een zeer belangrijke rol bij het in kaart brengen van gegevens over planten- en diersoorten. Uit de verzamelde feiten en cijfers blijkt ook dat bij alle huidige vormen van bodemgebruik er mogelijkheden en initiatieven zijn voor natuurcombinaties of voor het vergroten van de biodiversiteit.---For the Assessment of the Dutch Human Environment we want to review what is known about social activities, initiatives and combination of functions for nature and biodiversity and what they contribute to enhancing biodiversity. In this study we collected data from the available literature and websites. These facts and figures show that most people are involved with nature in one way or another and that the involvement of individuals and businesses in some activities is even increasing. Most green citizens' initiatives are focused on amenity green space, but sometimes important natural values that support international biodiversity targets are also created. In addition, citizens play a vital role in monitoring plant and animal species. These facts and figures show also that in all current forms of land use there are possibilities and initiatives for nature combinations or for increasing biodiversity
COMT Diplotype Amplifies Effect of Stress on Risk of Temporomandibular Pain
When measured once, psychological stress predicts development of painful temporomandibular disorder (TMD). However, a single measurement fails to characterize the dynamic nature of stress over time. Moreover, effects of stress on pain likely vary according to biological susceptibility. We hypothesized that temporal escalation in stress exacerbates risk for TMD, and the effect is amplified by allelic variants in a gene, catechol-O-methyltransferase (COMT), regulating catechol neurotransmitter catabolism. We used data from the Orofacial Pain: Prospective Evaluation and Risk Assessment prospective cohort study of 2,707 community-dwelling adults with no lifetime history of TMD on enrollment. At baseline and quarterly periods thereafter, the Perceived Stress Scale (PSS) measured psychological stress. Genotyped DNA from blood samples determined COMT diplotypes. During follow-up of 0.25 to 5.2 y, 248 adults developed examiner-verified incident TMD. PSS scores at baseline were 20% greater (P < 0.001) in adults who developed incident TMD compared with TMD-free controls. Baseline PSS scores increased by 9% (P = 0.003) during follow-up in cases but remained stable in controls. This stress escalation was limited to incident cases with COMT diplotypes coding for low-activity COMT, signifying impaired catabolism of catecholamines. Cox regression models confirmed significant effects on TMD hazard of both baseline PSS (P < 0.001), modeled as a time-constant covariate, and change in PSS (P < 0.001), modeled as a time-varying covariate. Furthermore, a significant (P = 0.04) interaction of COMT diplotype and time-varying stress showed that a postbaseline increase of 1.0 standard deviation in PSS more than doubled risk of TMD incidence in subjects with low-activity COMT diplotypes (hazard ratio = 2.35; 95% confidence limits: 1.66, 3.32), an effect not found in subjects with high-activity COMT diplotypes (hazard ratio = 1.42; 95% confidence limits: 0.96, 2.09). Findings provide novel insights into dynamic effects of psychological stress on TMD pain, highlighting that effects are most pronounced in individuals whose genetic susceptibility increases responsiveness to catecholamine neurotransmitters
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Unified concepts for understanding and modelling turnover of dissolved organic matter from freshwaters to the ocean: the UniDOM model
The transport of dissolved organic matter (DOM) across the land-ocean-aquatic continuum (LOAC), from freshwater to the ocean, is an important yet poorly understood component of the global carbon budget. Exploring and quantifying this flux is a significant challenge given the complexities of DOM cycling across these contrasting environments. We developed a new model, UniDOM, that unifies concepts, state variables and parameterisations of DOM turnover across the LOAC. Terrigenous DOM is divided into two pools, T1 (strongly-UV-absorbing) and T2 (non- or weakly-UV-absorbing), that exhibit contrasting responses to microbial consumption, photooxidation and flocculation. Data are presented to show that these pools are amenable to routine measurement based on specific UV absorbance (SUVA). In addition, an autochtonous DOM pool is defined to account for aquatic DOM production. A novel aspect of UniDOM is that rates of photooxidation and microbial turnover are parameterised as an inverse function of DOM age. Model results, which indicate that ~5% of the DOM originating in streams may penetrate into the open ocean, are sensitive to this parameterisation, as well as rates assigned to turnover of freshly produced DOM. The predicted contribution of flocculation to DOM turnover is remarkably low, although a mechanistic representation of this process in UniDOM was considered unachievable because of the complexities involved. Our work highlights the need for ongoing research into the mechanistic understanding and rates of photooxidation, microbial consumption and flocculation of DOM across the different environments of the LOAC, along with the development of models based on unified concepts and parameterisations
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