1,253 research outputs found
Marijuana Use Among Community College Students: A Study of Academic and Social Involvement
This quantitative study examined the effects of marijuana on academic and social involvement in undergraduates using a structural equation model. The study was conducted at a mid-sized comprehensive community college in the mid-West and was guided by Astinâs (1985) theory of student involvement and by Andersonâs (1998) cultural identity theory of drug abuse.
A survey link was e-mailed to all 4,527 eligible students at the college and 573 students participated in the study. Of the 573 students, 194 identified as users of marijuana and were used as the primary basis of the study. The data from the survey were used in a structural equation model to determine correlations between academic and social involvement and marijuana use. Independent samples t-tests were also used to compare users to non-users of marijuana.
The overall results of the study showed no significant correlation between marijuana use and academic and social involvement. Further, a positive, significant difference regarding academic involvement was revealed between infrequent users of marijuana compared to non-users. A negative, significant difference regarding social involvement was also found between more than once daily users of marijuana and non-users
Growth in the Real Size of Government since 1970
From at least 1893 economists have viewed income as an important determinant of government size and the hypothesis that government size increases with income is now enshrined in the literature as Wagnerâs Law. More recently, however, public choice economists and growth theorists have tended to reverse that causality by questioning whether government size is a constraint on (or promulgator of) economic growth. Typically, increases in government size arising from increased consumption are viewed as constraints on growth, while increases in size that arise from government investment are viewed as positive in their effect on growth. In this paper we are concerned with the two-way interrelationship between government size and income growth highlighted by these separate literatures and investigate this relationship in three distinct stages. In the first part of the paper we set out what has actually happened to the real size of government for twenty OECD countries over the period since 1970 and survey some of the newer factors and approaches used to explain its more recent evolution. The second part re-estimates the parameters of the demand curve for government allows us to speculate whether the changing pattern of government growth represents a break in the structure of the model determining government size or, more simply, represents a change in the variation of the underlying variables. We find that the same model works at least as well as it did in earlier periods with coefficients that are close to their earlier estimates. We follow this by estimating a simple growth model that highlights the size of government consumption in relation to income and output growth for the same countries over the same time period. Increases in size do appear to constrain economic growth. The third part of our paper recognizes that while each of the two causal relationships has received considerable attention in their own right, less attention has been given to effecting a separation of their co-mingled effects. To do so, we estimate the two relationships simultaneously in the context of our panel. This allows us assess whether ignoring the simultaneity of the two-way relationship seriously biases the measure of either the income effect (in determining government size) and/or the measure of governmentâs effect on economic growth when each are estimated separately. While our discussion suggests that single equation estimates of the income elasticity in Wagnerâs Law may have been biased upwards (in absolute terms) and the constraining effect of government size on growth biased downwards, our three stage estimates finds only modest support in the data. The paper concludes by exploring the interrelationship between government size and government regulation. In particular, we test the hypothesis that the appearance of slower growth in government side is due to the increased substitution of indirect control of private production for direct governmental output. On cross sectional data, we find the opposite. In our sample, larger government size is associated with more rather than less regulation.
Growth in the Real Size of Government since 1970
From at least 1893 economists have viewed income as an important determinant of government size and the hypothesis that government size increases with income is now enshrined in the literature as Wagner's Law. More recently, however, public choice economists and growth theorists have tended to reverse that causality by questioning whether government size is a constraint on (or promulgator of) economic growth. Typically, increases in government size arising from increased consumption are viewed as constraints on growth, while increases in size that arise from government investment are viewed as positive in their effect on growth. In this paper we are concerned with the two-way interrelationship between government size and income growth highlighted by these separate literatures and investigate this relationship in three distinct stages. In the first part of the paper we set out what has actually happened to the real size of government for twenty OECD countries over the period since 1970 and survey some of the newer factors and approaches used to explain its more recent evolution. The second part re-estimates the parameters of the demand curve for government allows us to speculate whether the changing pattern of government growth represents a break in the structure of the model determining government size or, more simply, represents a change in the variation of the underlying variables. We find that the same model works at least as well as it did in earlier periods with coefficients that are close to their earlier estimates. We follow this by estimating a simple growth model that highlights the size of government consumption in relation to income and output growth for the same countries over the same time period. Increases in size do appear to constrain economic growth. The third part of our paper recognizes that while each of the two causal relationships has received considerable attention in their own right, less attention has been given to effecting a separation of their co-mingled effects. To do so, we estimate the two relationships simultaneously in the context of our panel. This allows us assess whether ignoring the simultaneity of the two-way relationship seriously biases the measure of either the income effect (in determining government size) and/or the measure of government's effect on economic growth when each are estimated separately. While our discussion suggests that single equation estimates of the income elasticity in Wagner's Law may have been biased upwards (in absolute terms) and the constraining effect of government size on growth biased downwards, our three stage estimates finds only modest support in the data. The paper concludes by exploring the interrelationship between government size and government regulation. In particular, we test the hypothesis that the appearance of slower growth in government side is due to the increased substitution of indirect control of private production for direct governmental output. On cross sectional data, we find the opposite. In our sample, larger government size is associated with more rather than less regulation
Genomic patterns of malignant peripheral nerve sheath tumor (MPNST) evolution correlate with clinical outcome and are detectable in cell-free DNA
UNLABELLED: Malignant peripheral nerve sheath tumor (MPNST), an aggressive soft-tissue sarcoma, occurs in people with neurofibromatosis type 1 (NF1) and sporadically. Whole-genome and multiregional exome sequencing, transcriptomic, and methylation profiling of 95 tumor samples revealed the order of genomic events in tumor evolution. Following biallelic inactivation of NF1, loss of CDKN2A or TP53 with or without inactivation of polycomb repressive complex 2 (PRC2) leads to extensive somatic copy-number aberrations (SCNA). Distinct pathways of tumor evolution are associated with inactivation of PRC2 genes and H3K27 trimethylation (H3K27me3) status. Tumors with H3K27me3 loss evolve through extensive chromosomal losses followed by whole-genome doubling and chromosome 8 amplification, and show lower levels of immune cell infiltration. Retention of H3K27me3 leads to extensive genomic instability, but an immune cell-rich phenotype. Specific SCNAs detected in both tumor samples and cell-free DNA (cfDNA) act as a surrogate for H3K27me3 loss and immune infiltration, and predict prognosis.
SIGNIFICANCE: MPNST is the most common cause of death and morbidity for individuals with NF1, a relatively common tumor predisposition syndrome. Our results suggest that somatic copy-number and methylation profiling of tumor or cfDNA could serve as a biomarker for early diagnosis and to stratify patients into prognostic and treatment-related subgroups. This article is highlighted in the In This Issue feature, p. 517
Mouse tissue harvest-induced hypoxia rapidly alters the in vivo metabolome, between-genotype metabolite level differences, and 13C-tracing enrichments
OBJECTIVE: Metabolomics as an approach to solve biological problems is exponentially increasing in use. Thus, this a pivotal time for the adoption of best practices. It is well known that disrupted tissue oxygen supply rapidly alters cellular energy charge. However, the speed and extent to which delayed mouse tissue freezing after dissection alters the broad metabolome is not well described. Furthermore, how tissue genotype may modulate such metabolomic drift and the degree to which traced
METHODS: By combined liquid chromatography (LC)- and gas chromatography (GC)-mass spectrometry (MS), we measured how levels of 255 mouse liver metabolites changed following 30-second, 1-minute, 3-minute, and 10-minute freezing delays. We then performed test-of-concept delay-to-freeze experiments evaluating broad metabolomic drift in mouse heart and skeletal muscle, differential metabolomic change between wildtype (WT) and mitochondrial pyruvate carrier (MPC) knockout mouse livers, and shifts in
RESULTS: Our data demonstrate that delayed mouse tissue freezing after dissection leads to rapid hypoxia-driven remodeling of the broad metabolome, induction of both false-negative and false-positive between-genotype differences, and restructuring of
CONCLUSIONS: Our findings provide a previously absent, systematic illustration of the extensive, multi-domain metabolomic changes occurring within the early minutes of delayed tissue freezing. They also provide a novel, detailed resource of mouse liver ex vivo, hypoxic metabolomic remodeling
Summary of the Very Large Hadron Collider Physics and Detector Workshop
One of the options for an accelerator beyond the LHC is a hadron collider
with higher energy. Work is going on to explore accelerator technologies that
would make such a machine feasible. This workshop concentrated on the physics
and detector issues associated with a hadron collider with an energy in the
center of mass of the order of 100 to 200 TeV
Targeting Conservation Investments in Heterogeneous Landscapes: A distance function approach and application to watershed management
To achieve a given level of an environmental amenity at least cost, decision-makers must integrate information about spatially variable biophysical and economic conditions. Although the biophysical attributes that contribute to supplying an environmental amenity are often known, the way in which these attributes interact to produce the amenity is often unknown. Given the difficulty in converting multiple attributes into a unidimensional physical measure of an environmental amenity (e.g., habitat quality), analyses in the academic literature tend to use a single biophysical attribute as a proxy for the environmental amenity (e.g., species richness). A narrow focus on a single attribute, however, fails to consider the full range of biophysical attributes that are critical to the supply of an environmental amenity. Drawing on the production efficiency literature, we introduce an alternative conservation targeting approach that relies on distance functions to cost-efficiently allocate conservation funds across a spatially heterogeneous landscape. An approach based on distance functions has the advantage of not requiring a parametric specification of the amenity function (or cost function), but rather only requiring that the decision-maker identify important biophysical and economic attributes. We apply the distance-function approach empirically to an increasingly common, but little studied, conservation initiative: conservation contracting for water quality objectives. The contract portfolios derived from the distance-function application have many desirable properties, including intuitive appeal, robust performance across plausible parametric amenity measures, and the generation of ranking measures that can be easily used by field practitioners in complex decision-making environments that cannot be completely modeled. Working Paper # 2002-01
Treatment of Travel Expenses by Golf Course Patrons: Sunk or Bundled Costs and the First and Third Laws of Demand
To attract golf patrons, sport managers must understand consumption patterns of the golfer. Importantly, the treatment of travel costs must be understood. According to the Alchian-Allen (1964) theorem, golfers treat travel costs as bundled costs (third law of economic demand) whereas classical consumer theory indicates that golfers treat travel costs as sunk costs (first law of economic demand). The purpose of this study was to determine if golf patrons treated travel costs as sunk costs or if they treated travel costs as a bundled cost. Data from a survey of course patrons in Ohio support the treatment of travel costs as bundled costs by golf course patrons, especially those classified as tourists. The strong, positive correlation found between distance traveled and the cost of greens fees enables managers to utilize geographic segmentation in choosing to whom to market their course based upon their productâs price compared to area competitors
A Precise Measurement of the Weak Mixing Angle in Neutrino-Nucleon Scattering
We report a precise measurement of the weak mixing angle from the ratio of
neutral current to charged current inclusive cross-sections in deep-inelastic
neutrino-nucleon scattering. The data were gathered at the CCFR neutrino
detector in the Fermilab quadrupole-triplet neutrino beam, with neutrino
energies up to 600 GeV. Using the on-shell definition, , we obtain .Comment: 10 pages, Nevis Preprint #1498 (Submitted to Phys. Rev. Lett.
Determination of the Strange Quark Content of the Nucleon from a Next-to-Leading-Order QCD Analysis of Neutrino Charm Production
We present the first next-to-leading-order QCD analysis of neutrino charm
production, using a sample of 6090 - and -induced
opposite-sign dimuon events observed in the CCFR detector at the Fermilab
Tevatron. We find that the nucleon strange quark content is suppressed with
respect to the non-strange sea quarks by a factor \kappa = 0.477 \:
^{+\:0.063}_{-\:0.053}, where the error includes statistical, systematic and
QCD scale uncertainties. In contrast to previous leading order analyses, we
find that the strange sea -dependence is similar to that of the non-strange
sea, and that the measured charm quark mass, , is larger and consistent with that determined in other processes.
Further analysis finds that the difference in -distributions between
and is small. A measurement of the Cabibbo-Kobayashi-Maskawa
matrix element is also presented.
uufile containing compressed postscript files of five Figures is appended at
the end of the LaTeX source.Comment: Nevis R#150
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