1,084 research outputs found
Exposure to tobacco smoke in utero or during early childhood and risk of hypomania: prospective birth cohort study
Objectives:
Using data from a prospective birth cohort, we aimed to test for an association between exposure to tobacco smoke in utero or during early development and the experience of hypomania assessed in young adulthood.
Methods:
We used data on 2957 participants from a large birth cohort (Avon longitudinal study of parents and children [ALSPAC]). The primary outcome of interest was hypomania, and the secondary outcome was “hypomania plus previous psychotic experiences (PE)”. Maternally-reported smoking during pregnancy, paternal smoking and exposure to environmental tobacco smoke (ETS) in childhood were the exposures of interest. Multivariable logistic regression was used and estimates of association were adjusted for socio-economic, lifestyle and obstetric factors.
Results:
There was weak evidence of an association between exposure to maternal smoking in utero and lifetime hypomania. However, there was a strong association of maternal smoking during pregnancy within the sub-group of individuals with hypomania who had also experienced psychotic symptoms (OR = 3.45; 95% CI: 1.49–7.98; P = 0.004). There was no association between paternal smoking, or exposure to ETS during childhood, and hypomania outcomes.
Conclusions:
Exposure to smoking in utero may be a risk factor for more severe forms of psychopathology on the mood-psychosis spectrum, rather than DSM-defined bipolar disorder
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Recent developments in high-speed, non-sampling electromagnetic calorimetry
Brief discussions are given of the work that has been done on the suppression of the slow component in BaF{sub 2}, the developments in the understanding of undoped CsI, and the properties of the new scintillator CeF{sub 3}. The properties of the Cherenkov radiator PbF{sub 2} along with test beam results are presented. Monte Carlo simulations indicate that, with the addition of a small amount of scintillator, PbF{sub 2}, can be made hadron compensating off-line so that the resolution of a compensating hadron calorimeter will not be degraded by its presence. 14 refs., 6 figs., 4 tabs
A functional central limit theorem for a Markov-modulated infinite-server queue
We consider a model in which the production of new molecules in a chemical reaction network occurs in a seemingly stochastic fashion, and can be modeled as a Poisson process with a varying arrival rate: the rate is when an external Markov process is in state . It is assumed that molecules decay after an exponential time with mean .
The goal of this work is to analyze the distributional properties of the number of molecules in the system, under a specific time-scaling. In this scaling, the background process is sped
up by a factor , for some , whereas the arrival rates become , for large.
The main result of this paper is a functional central limit theorem ({\sc f-clt}) for the number of molecules, in that the number of molecules, after centering and scaling, converges to an Ornstein-Uhlenbeck process. An interesting dichotomy is observed: (i)~if the background process jumps faster than the arrival process, and consequently the arrival process behaves essentially as a (homogeneous) Poisson process, so that the scaling in the {\sc f-clt} is the usual , whereas (ii)~for the background process is relatively slow, and the scaling in the {\sc f-clt} is In the latter regime, the parameters of the limiting Ornstein-Uhlenbeck process contain the deviation matrix associated with the background process
Zero-divisor graphs of nilpotent-free semigroups
We find strong relationships between the zero-divisor graphs of apparently
disparate kinds of nilpotent-free semigroups by introducing the notion of an
\emph{Armendariz map} between such semigroups, which preserves many
graph-theoretic invariants. We use it to give relationships between the
zero-divisor graph of a ring, a polynomial ring, and the annihilating-ideal
graph. Then we give relationships between the zero-divisor graphs of certain
topological spaces (so-called pearled spaces), prime spectra, maximal spectra,
tensor-product semigroups, and the semigroup of ideals under addition,
obtaining surprisingly strong structure theorems relating ring-theoretic and
topological properties to graph-theoretic invariants of the corresponding
graphs.Comment: Expanded first paragraph in section 6. To appear in J. Algebraic
Combin. 22 page
Eureka and beyond: mining's impact on African urbanisation
This collection brings separate literatures on mining and urbanisation together at a time when both artisanal and large-scale mining are expanding in many African economies. While much has been written about contestation over land and mineral rights, the impact of mining on settlement, notably its catalytic and fluctuating effects on migration and urban growth, has been largely ignored. African nation-states’ urbanisation trends have shown considerable variation over the past half century. The current surge in ‘new’ mining countries and the slow-down in ‘old’ mining countries are generating some remarkable settlement patterns and welfare outcomes. Presently, the African continent is a laboratory of national mining experiences. This special issue on African mining and urbanisation encompasses a wide cross-section of country case studies: beginning with the historical experiences of mining in Southern Africa (South Africa, Zambia, Zimbabwe), followed by more recent mineralizing trends in comparatively new mineral-producing countries (Tanzania) and an established West African gold producer (Ghana), before turning to the influence of conflict minerals (Angola, the Democratic Republic of Congo and Sierra Leone)
The association between driving time and unhealthy lifestyles: a cross-sectional, general population study of 386 493 UK Biobank participants
Background:
Driving is a common type of sedentary behaviour; an independent risk factor for poor health. The study explores whether driving is also associated with other unhealthy lifestyle factors.
Methods:
In a cross-sectional study of UK Biobank participants, driving time was treated as an ordinal variable and other lifestyle factors dichotomized into low/high risk based on guidelines. The associations were explored using chi-square tests for trend and binary logistic regression.
Results:
Of the 386 493 participants who drove, 153 717 (39.8%) drove <1 h/day; 140 140 (36.3%) 1 h/day; 60 973 (15.8%) 2 h/day; and 31 663 (8.2%) ≥3 h/day. Following adjustment for potential confounders, driving ≥3 h/day was associated with being overweight/obese (OR = 1.74, 95% CI: 1.64–1.85), smoking (OR = 1.48, 95% CI: 1.37–1.63), insufficient sleep (1.70, 95% CI: 1.61–1.80), low fruit/vegetable intake (OR = 1.26, 95% CI: 1.18–1.35) and low physical activity (OR = 1.05, 95% CI: 1.00–1.11), with dose relationships for the first three, but was not associated with higher alcohol consumption (OR = 0.94, 95% CI: 0.87–1.02).
Conclusions:
Sedentary behaviour, such as driving, is known to have an independent association with adverse health outcomes. It may have additional impact mediated through its effect on other aspects of lifestyle. People with long driving times are at higher risk and might benefit from targeted interventions
Dark Energy and Extending the Geodesic Equations of Motion: Its Construction and Experimental Constraints
With the discovery of Dark Energy, , there is now a universal
length scale, , associated with the
universe that allows for an extension of the geodesic equations of motion. In
this paper, we will study a specific class of such extensions, and show that
contrary to expectations, they are not automatically ruled out by either
theoretical considerations or experimental constraints. In particular, we show
that while these extensions affect the motion of massive particles, the motion
of massless particles are not changed; such phenomena as gravitational lensing
remain unchanged. We also show that these extensions do not violate the
equivalence principal, and that because Mpc, a
specific choice of this extension can be made so that effects of this extension
are not be measurable either from terrestrial experiments, or through
observations of the motion of solar system bodies. A lower bound for the only
parameter used in this extension is set.Comment: 19 pages. This is the published version of the first half of
arXiv:0711.3124v2 with corrections include
Josephson Current in the Presence of a Precessing Spin
The Josephson current in the presence of a precessing spin between various
types of superconductors is studied. It is shown that the Josephson current
flowing between two spin-singlet pairing superconductors is not modulated by
the precession of the spin. When both superconductors have equal-spin-triplet
pairing state, the flowing Josephson current is modulated with twice of the
Larmor frequency by the precessing spin. It was also found that up to the
second tunneling matrix elements, no Josephson current can occur with only a
direct exchange interaction between the localized spin and the conduction
electrons, if the two superconductors have different spin-parity pairing
states.Comment: 5 pages, 1 figur
Dilute Bose gas in two dimensions: Density expansions and the Gross-Pitaevskii equation
A dilute two-dimensional (2D) Bose gas at zero temperature is studied by the
method developed earlier by the authors. Low density expansions are derived for
the chemical potential, ground state energy, kinetic and interaction energies.
The expansion parameter is found to be a dimensionless in-medium scattering
amplitude u obeying the equation 1/u+\ln u=-\ln(na^2\pi)-2\gamma, where na^2
and \gamma are the gas parameter and the Euler constant, respectively. It is
shown that the ground state energy is mostly kinetic in the low density limit;
this result does not depend on a specific form of the pairwise interaction
potential, contrary to 3D case. A new form of 2D Gross-Pitaevskii equation is
proposed within our scheme.Comment: 4 pages, REVTeX, no figure
Differentiating normal and problem gambling: a grounded theory approach.
A previous study (Ricketts & Macaskill, 2003) delineated a theory of problem gambling based on the experiences of treatment seeking male gamblers and allowed predictions to be made regarding the processes that differentiate between normal and problem gamblers. These predictions are the focus of the present study, which also utilised a grounded theory approach, but with a sample of male high frequency normal gamblers. The findings suggest that there are common aspects of gambling associated with arousal and a sense of achievement. The use of gambling to manage negative emotional states differentiated normal and problem gambling. Perceived self-efficacy , emotion management skills and perceived likelihood of winning money back were intervening variables differentiating problem and normal gamblers.</p
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