Association Between the Seated Single-Arm Shot-Put Test With Isokinetic Pushing Force

Context: Previous investigations have examined the reliability, normalization, and underlying projection mechanics of the seated single-arm shot-put (SSASP) test. Although the test is believed to reflect test limb strength, there have been no assessments determining whether test performance is directly associated with upper-extremity strength. Objective: To determine the relationship between isokinetic pushing force and SSASP performance and conduct a method comparison analysis of limb symmetry indices between the 2 tests. Design: Controlled laboratory study. Setting: Biomechanics laboratory. Patients (or Other Participants): Twenty-four healthy and physically active men (n = 12) and women (n = 12). Intervention(s): Participants completed the SSASP and isokinetic pushing tests using their dominant and nondominant arms.Main OutcomeMeasures: SSASP distance and isokinetic peak force. Results: Significant moderate to strong relationships were revealed between the SSASP distances and isokinetic peak forces for both limbs. The Bland–Altman analysis results demonstrated significantly (P \u3c .002) greater limb symmetry indices for the SSASP (both medicine balls) than the isokinetic ratios, with biases ranging from −0.094 to −0.159. The limits of agreement results yielded intervals ranging from ±0.241 to ±0.340 and ±0.202 to ±0.221 from the biases. Conclusions: These results support the notion that the SSASP test reflects upper-extremity strength. The incongruency of the limb symmetry indices between the 2 tests is likely reflective of the differences in the movement patterns and coordination requirements of the 2 tests

A Survey for Low-Surface-Brightness Galaxies Around M31. I. The Newly Discovered Dwarf Andromeda V

We present images and a color-magnitude diagram for And V, a new dwarf spheroidal companion to M31 that was found using a digital filtering technique applied to 1550 square degrees of the second Palomar Sky Survey. And V resolves into stars easily in follow-up 4-m V- and I-band images, from which we deduce a distance of 810 +/- 45 kpc using the tip of the red giant branch method. Within the uncertainties, this distance is identical to the Population II distances for M31 and, combined with a projected separation of 112 kpc, provides strong support for a physical association between the two galaxies. There is no emission from And V detected in H alpha, 1.4 GHz radio continuum, or IRAS bandpasses, and there is no young population seen in the color-magnitude diagram that might suggest that And V is an irregular. Thus, the classification as a new dwarf spheroidal member of the Local Group seems secure. With an extinction-corrected central surface brightness of 25.2 V mag per square arcsec, a mean metal abundance of [Fe/H] approximately -1.5, and no evidence for upper AGB stars, And V resembles And I & III.Comment: Accepted for publication in The Astronomical Journal, November 1998 issue; 4 embedded PostScript figures, 4 JPEG figures; see http://aloe.tuc.noao.edu/jacoby/dwarfs.html for a complete full-resolution PostScript versio

Invasion genetics of New World medflies: testing alternative colonization scenarios

The Mediterranean fruit fly (Ceratitis capitata) is an invasive agricultural pest with a wide host range and a nearly global distribution. Efforts to forgo the medfly\u27\u27s spread into the United States are dependent on an understanding of population dynamics in newly established populations elsewhere. To explore the potential influence of demographic and historical parameters in six medfly populations distributed from Mexico to Peru, we created population genetic null models using Monte Carlo simulations. Null expectations for genetic differentiation (F ST) were compared with actual sequence variation from four highly polymorphic nuclear loci. Four colonization scenarios that were modeled led to unique genetic signatures that could be used to interpret empirical data. Unless current gene flow across Latin America was assumed to be very high, we could reject colonizations consisting of multiple introductions, each of low genetic diversity. Further, if simulated populations were small (N e = 5 × 102 individuals per population), small invasions from a single source consistently produced F ST values comparable to those currently observed in Latin America. In contrast, only large invasions from diverse sources were compatible with the observed data for large populations (N e 5 × 103). This study demonstrates that alternative population genetic hypotheses can be tested empirically even when departures from equilibrium are extreme, and that population genetic theory can be used to explore the processes that underlie biological invasions

Interpreting Mendelian-randomization estimates of the effects of categorical exposures such as disease status and educational attainment

BACKGROUND: Mendelian randomization has been previously used to estimate the effects of binary and ordinal categorical exposures—e.g. Type 2 diabetes or educational attainment defined by qualification—on outcomes. Binary and categorical phenotypes can be modelled in terms of liability—an underlying latent continuous variable with liability thresholds separating individuals into categories. Genetic variants influence an individual’s categorical exposure via their effects on liability, thus Mendelian-randomization analyses with categorical exposures will capture effects of liability that act independently of exposure category. METHODS AND RESULTS: We discuss how groups in which the categorical exposure is invariant can be used to detect liability effects acting independently of exposure category. For example, associations between an adult educational-attainment polygenic score (PGS) and body mass index measured before the minimum school leaving age (e.g. age 10 years), cannot indicate the effects of years in full-time education on this outcome. Using UK Biobank data, we show that a higher educational-attainment PGS is strongly associated with lower smoking initiation and higher odds of glasses use at age 15 years. These associations were replicated in sibling models. An orthogonal approach using the raising of the school leaving age (ROSLA) policy change found that individuals who chose to remain in education to age 16 years before the reform likely had higher liability to educational attainment than those who were compelled to remain in education to age 16 years after the reform, and had higher income, lower pack-years of smoking, higher odds of glasses use and lower deprivation in adulthood. These results suggest that liability to educational attainment is associated with health and social outcomes independently of years in full-time education. CONCLUSIONS: Mendelian-randomization studies with non-continuous exposures should be interpreted in terms of liability, which may affect the outcome via changes in exposure category and/or independently

Reliability of Upper Extremity Functional Performance Tests for the Non-overhead Athlete

# Background While there have been reliability studies conducted on several upper extremity functional performance tests (UEFPT), there are several complicating factors that inhibit the ability to draw definitive consensus about the reliability of the tests in both females and males. Having reliability estimates for UEFPT in the same cohort facilitates direct comparison of their relative and absolute reliability. # Purpose To establish the test-retest reliability of the closed kinetic chain upper extremity stability test (CKCUEST), seated medicine ball chest pass test (SMBCPT) and hands-release push-up test (HRPUT) in a cohort of males and females with a history of non-overhead sport participation. A secondary purpose was to examine the associations between the three UEFPT. # Study Design Test-retest reliability, single cohort study. # Methods Forty adults (20 females, 20 males) with a history of non-overhead sport participation completed three UEFPT during two data collection sessions three to seven days apart. Measures of systematic bias, absolute reliability and relative reliability were computed between the sessions. Additionally, correlational analyses were conducted between the three UEFPT. # Results Only the UECKCST (both sexes) demonstrated significant (p≤ 0.003) second session performance improvements. All three tests exhibited excellent relative reliability (intraclass correlational coefficients ≥ 0.823) and except for the HRPUT in males, coefficients of variation were all below 8.8%. Except for a significant relationship (r=.691, p=0.001) between the UECKCST and SMBCPT for the females there were no other associations between the three UEFPT. # Conclusion All three UEFPT demonstrated sufficient reliability. Thus, all three assessments can be used for serial assessments to progress a patient through rehabilitation as well as contribute to the criteria used in making return to sport decisions. # Level of Evidence

Kinematic Analysis of Four Plyometric Push-Up Variations

International Journal of Exercise Science 5(4) : 334-343, 2012. Plyometric research in the upper extremity is limited, with the effects of open-chain plyometric exercises being studied most. Kinematic and ground reaction force data concerning closed-chain upper extremity plyometrics has yet to be examined. Twenty-one recreationally active male subjects performed four variations of plyometric push-ups in a counterbalanced order. These included box drop push-ups from 3.8 cm, 7.6 cm, 11.4 cm heights, and clap push-ups. Kinematics of the trunk, dominant extremity and both hands were collected to examine peak flight, elbow flexion at ground contact, elbow displacement, and hand separation. Additionally peak vertical ground reaction force was measured under the dominant extremity. The 11.4 cm and clap push-ups had significantly higher peak flight than the other variations (P\u3c.001). At ground contact, the elbow was in significantly greater flexion for the 3.8 cm and clap push-up compared to the other variations (P\u3c.001). The clap push-up had significantly more elbow displacement than the other variations (P\u3c.001) while hand separation was not significantly different between variations (P=.129). Peak vertical ground reaction force was significantly greater for the clap push-ups than for all other variations (P\u3c .001). Despite similar flight heights between the 11.4 cm and clap push-ups, the greater peak vertical ground reaction force and elbow displacement of the clap push-ups indicates the clap push-up is the most intense of the variations examined. Understanding the kinematic variables involved will aid in the creation of a closed chain upper-extremity plyometric progression

The causal effects of education on adult health, mortality and income: evidence from Mendelian randomization and the raising of the school leaving age

BACKGROUND: On average, educated people are healthier, wealthier and have higher life expectancy than those with less education. Numerous studies have attempted to determine whether education causes differences in later health outcomes or whether another factor ultimately causes differences in education and subsequent outcomes. Previous studies have used a range of natural experiments to provide causal evidence. Here we compare two natural experiments: a policy reform, raising the school leaving age in the UK in 1972; and Mendelian randomization. METHODS: We used data from 334 974 participants of the UK Biobank, sampled between 2006 and 2010. We estimated the effect of an additional year of education on 25 outcomes, including mortality, measures of morbidity and health, ageing and income, using multivariable adjustment, the policy reform and Mendelian randomization. We used a range of sensitivity analyses and specification tests to assess the plausibility of each method's assumptions. RESULTS: The three different estimates of the effects of educational attainment were largely consistent in direction for diabetes, stroke and heart attack, mortality, smoking, income, grip strength, height, body mass index (BMI), intelligence, alcohol consumption and sedentary behaviour. However, there was evidence that education reduced rates of moderate exercise and increased alcohol consumption. Our sensitivity analyses suggest that confounding by genotypic or phenotypic confounders or specific forms of pleiotropy are unlikely to explain our results. CONCLUSIONS: Previous studies have suggested that the differences in outcomes associated with education may be due to confounding. However, the two independent sources of exogenous variation we exploit largely imply consistent causal effects of education on outcomes later in life

The White Dwarfs within 20 Parsecs of the Sun: Kinematics and Statistics

We present the kinematical properties, distribution of spectroscopic subtypes, stellar population subcomponents of the white dwarfs within 20 pc of the sun. We find no convincing evidence of halo white dwarfs in the total 20 pc sample of 129 white dwarfs nor is there convincing evidence of genuine thick disk subcomponent members within 20 parsecs. Virtually the entire 20 pc sample likely belongs to the thin disk. The total DA to non-DA ratio of the 20 pc sample is 1.6, a manifestation of deepening envelope convection which transforms DA stars with sufficiently thin H surface layers into non-DAs. The addition of 5 new stars to the 20 pc sample yields a revised local space density of white dwarfs of $4.9\pm0.5 \times 10^{-3}$ M_{\sun}/yr and a corresponding mass density of $3.3\pm0.3 \times 10^{-3}$ M_{\sun}/pc$^{3}$. We find that at least 15% of the white dwarfs within 20 parsecs of the sun (the DAZ and DZ stars) have photospheric metals that possibly originate from accretion of circumstellar material (debris disks) around them. If this interpretation is correct, this suggests the possibility that the same percentage have planets or asteroid-like bodies orbiting them.Comment: Accepted for publication in The Astronomical Journa

Taller height and risk of coronary heart disease and cancer:A within-sibship Mendelian randomization study

BACKGROUND: Taller people have a lower risk of coronary heart disease but a higher risk of many cancers. Mendelian randomization (MR) studies in unrelated individuals (population MR) have suggested that these relationships are potentially causal. However, population MR studies are sensitive to demography (population stratification, assortative mating) and familial (indirect genetic) effects. METHODS: In this study, we performed within-sibship MR analyses using 78,988 siblings, a design robust against demography and indirect genetic effects of parents. For comparison, we also applied population MR and estimated associations with measured height. RESULTS: Within-sibship MR estimated that 1 SD taller height lowers the odds of coronary heart disease by 14% (95% CI: 3–23%) but increases the odds of cancer by 18% (95% CI: 3–34%), highly consistent with population MR and height-disease association estimates. There was some evidence that taller height reduces systolic blood pressure and low-density lipoprotein cholesterol, which may mediate some of the protective effects of taller height on coronary heart disease risk. CONCLUSIONS: For the first time, we have demonstrated that the purported effects of height on adulthood disease risk are unlikely to be explained by demographic or familial factors, and so likely reflect an individual-level causal effect. Disentangling the mechanisms via which height affects disease risk may improve the understanding of the etiologies of atherosclerosis and carcinogenesis. FUNDING: This project was conducted by researchers at the MRC Integrative Epidemiology Unit (MC_UU_00011/1) and also supported by a Norwegian Research Council Grant number 295989

Nuclear Effects on Heavy Boson Production at RHIC and LHC

We predict W and Z transverse momentum distributions from proton-proton and nuclear collisions at RHIC and LHC. A resummation formalism with power corrections to the renormalization group equations is used. The dependence of the resummed QCD results on the non-perturbative input is very weak for the systems considered. Shadowing effects are discussed and found to be unimportant at RHIC, but important for LHC. We study the enhancement of power corrections due to multiple scattering in nuclear collisions and numerically illustrate the weak effects of the dependence on the nuclear mass.Comment: 21 pages, 11 figure