19,997 research outputs found
Relationships among fat mass, fat-free mass and height in adults: A new method of statistical analysis applied to NHANES data
Objectives:
The positive influence of fat mass (FM) on fat-free mass (FFM) has been quantified previously by various methods involving regression analysis of population data, but some are fundamentally flawed through neglect of the tendency of taller individuals to carry more fat. Differences in FFM due to differences in FMâand not directly related to differences in heightâare expressed as ÎFFM/ÎFM, denoted KF. The main aims were to find a sounder regression-based method of quantifying KF and simultaneously of estimating mean BMI0, the BMI of hypothetical fat-free individuals. Other, related, objectives were to check the linearity of FFM-FM relationships and to quantify the correlation between FM and height.
Methods:
New statistical methods, explored and verified by Monte Carlo simulation, were applied to NHANES data. Regression of height2 on FFM and FM produced estimates of mean KF and indirectly of BMI0. Both were then adjusted to allow for variability in KF around its mean. Its standard deviation was estimated by a novel method.
Results:
Relationships between FFM and FM were linear, not semilogarithmic as is sometimes assumed. Mean KF is similar in Mexican American men and women, but higher in men than women in non-Hispanic European Americans and African Americans. Mean BMI0 is higher in men than in women. FM correlates more strongly with height than has been found previously.
Conclusions:
A more accurate way of quantifying mean BMI0 and the dependence of FFM on FM is established that may be easily applied to new and existing population data
The Growth in Applications for Social Security Disability Insurance: A Spillover Effect from Workersâ Compensation
We investigate the determinants of application for Social Security Disability Insurance (DI) benefits in approxiÂmately 45 jurisdictions between 1981 and 1999. We reproduce findings of previous studies of the determinants of DI application then test the additional influence of changes to workersâ compensation program benefits and rules on DI application rates. Our findings indicate that the programs are interrelated: When workersâ compensation benefits declined and eligibility rules tightened in the 1990s, the DI application rate increased
Taylor Rules, McCallum Rules and the Term Structure of Interest Rates
term structure, monetary policy, Taylor rule
Workers' Compensation Under Alternative Insurance Arrangements
The authors use a unique panel data set of state-level data for 48 jurisdictions between 1975 and 1995 to explore the effects of insurance arrangements on workplace safety, the structure of the workers' compensation insurance market, and the employers' costs of workers' compensation insurance. In addition, we examine the trade-off between the benefit adequacy and affordability objectives of state workers' compensation programs and estimate the impact that the imposition of federal standards for benefit adequacy would have on workers' compensation costs
Do Fixed Exchange Rates Fetter Monetary Policy? A Credit View
The Bernanke-Blinder credit-view model is expanded to encompass a small, open economy with fixed exchange rates. In contrast to conventional wisdom and traditional models, monetary policy is resurrected as a stabilization tool. We show that various financial sector shocks have real aggregate demand effects. Further, we demonstrate that independent monetary policy actions can have substantive impacts on aggregate demand despite perfect capital mobility in bond markets and adherence to a fixed exchange rate regime as long as bank loans are imperfectly mobile.
On the stability of travelling waves with vorticity obtained by minimisation
We modify the approach of Burton and Toland [Comm. Pure Appl. Math. (2011)]
to show the existence of periodic surface water waves with vorticity in order
that it becomes suited to a stability analysis. This is achieved by enlarging
the function space to a class of stream functions that do not correspond
necessarily to travelling profiles. In particular, for smooth profiles and
smooth stream functions, the normal component of the velocity field at the free
boundary is not required a priori to vanish in some Galilean coordinate system.
Travelling periodic waves are obtained by a direct minimisation of a functional
that corresponds to the total energy and that is therefore preserved by the
time-dependent evolutionary problem (this minimisation appears in Burton and
Toland after a first maximisation). In addition, we not only use the
circulation along the upper boundary as a constraint, but also the total
horizontal impulse (the velocity becoming a Lagrange multiplier). This allows
us to preclude parallel flows by choosing appropriately the values of these two
constraints and the sign of the vorticity. By stability, we mean conditional
energetic stability of the set of minimizers as a whole, the perturbations
being spatially periodic of given period.Comment: NoDEA Nonlinear Differential Equations and Applications, to appea
The Employers' cost of Workers' Compensation Insurance: Magnitudes, Determinants, and Public Policy
This paper presents estimates of the average cost of the workers' compensation insurance program for a homogeneous group of employers by state. These estimates are of interest because they reflect the operation, direct nominal costs, and efficiency of workers' compensation. The paper estimates cost equations for a variety of alternative specifications. The main finding is that when cost equations are estimated by ordinary least squares there is a unit elasticity of costs with respect to benefits, but instrumental variable estimates of the effect of benefits yield a greater than unit elasticity. The results also indicate that the presence of a state insurance fund is associated with higher average costs to employers, all else equal. Finally, we explore the impact that the minimum standards recommended by the National Commission on State Workmen's Compensation Laws would have on workers' compensation costs.
ISM gas studies towards the TeV PWN HESS J1825-137 and northern region
HESS J1825-137 is a pulsar wind nebula (PWN) whose TeV emission extends
across ~1 deg. Its large asymmetric shape indicates that its progenitor
supernova interacted with a molecular cloud located in the north of the PWN as
detected by previous CO Galactic survey (e.g Lemiere, Terrier &
Djannati-Ata\"i 2006). Here we provide a detailed picture of the ISM towards
the region north of HESS J1825-137, with the analysis of the dense molecular
gas from our 7mm and 12mm Mopra survey and the more diffuse molecular gas from
the Nanten CO(1-0) and GRS CO(1-0) surveys. Our focus is the possible
association between HESS J1825-137 and the unidentified TeV source to the
north, HESS J1826-130. We report several dense molecular regions whose
kinematic distance matched the dispersion measured distance of the pulsar.
Among them, the dense molecular gas located at (RA,
Dec)=(18.421h,-13.282) shows enhanced turbulence and we suggest that
the velocity structure in this region may be explained by a cloud-cloud
collision scenario. Furthermore, the presence of a H rim may be the
first evidence of the progenitor SNR of the pulsar PSR J1826-1334 as the
distance between the H rim and the TeV source matched with the
predicted SNR radius R~120 pc. From our ISM study, we identify a
few plausible origins of the HESS J1826-130 emission, including the progenitor
SNR of PSR J1826-1334 and the PWN G018.5-0.4 powered by PSR J1826-1256. A
deeper TeV study however, is required to fully identify the origin of this
mysterious TeV source.Comment: 19 figures, 27 pages, accepted by MNRA
Keeping the Light Shining? The end of British Quakerism Revisited
This paper follows on from two earlier articles in Quaker Studies on the predicted end-point for the Religious Society of Friends in Britain and presents analyses of the membership data for individual General Meetings (GMs) within Britain Yearly Meeting which suggest that the picture is not as straightforward as initially presented in the earlier articles. Based on an analysis of membership numbers since 1899, some GMs are predicted to increase over the next 30 years, although most will apparently decline. The data are also analysed on a regional basis and three models of the changing membership are presented
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