26,017 research outputs found

    The large-scale modulation of cosmic rays in mid-1982: Its dependence on heliospheric longitude and radius

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    Near solar maximum, a series of large radial solar wind shocks in June and July 1982 provided a unique opportunity to study the solar modulation of galactic cosmic rays with an array of spacecraft widely separated both in heliocentric radius and longitude. By eliminating hysteresis effects it is possible to begin to separate radial and azimuthal effects in the outer heliosphere. On the large scale, changes in modulation (both the increasing and recovery phases) propagate outward at close to the solar wind velocity, except for the near-term effects of solar wind shocks, which may propagate at a significantly higher velocity. In the outer heliosphere, azimuthal effects are small in comparison with radial effects for large-scale modulation at solar maximum

    Get your facts right : preschoolers systematically extend both object names and category-relevant facts

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    There is an ongoing debate over the extent to which language development shares common processing mechanisms with other domains of learning. It is well-established that toddlers will systematically extend object labels to similarly-shaped category exemplars (e.g., Landau, Smith, & Jones, 1988; Markman & Hutchinson, 1984). However, previous research is inconclusive as to whether young children will similarly extend factual information about an object to other category members. We explicitly contrast facts varying in category relevance, and test for extension using two different tasks. Three- to four-year-olds (N = 61) were provided with one of three types of information about a single novel object: a category-relevant fact (‘it’s from a place called Modi’), a category-irrelevant fact (‘my uncle gave it to me’), or an object label (‘it’s called a Modi’). At test, children provided with the object name or category-relevant fact were significantly more likely to display systematic category extension than children who learnt the category-irrelevant fact. Our findings contribute to a growing body of evidence that the mechanisms responsible for word learning may be domain-general in nature

    INDIVIDUAL JOINT MOMENT STRATEGIES UTILIZED DURING THE SUPPORT PHASE OF RUNNING

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    Typically ground reaction force parameters have been used to determine individual kinetic strategies for accommodating impact and loading forces incurred during running. Joint moments are also useful indicators of the amount of physical stress placed on the neuromuscular system (Winter, 1983). General patterns ofjoint moments (MJ) during the support period can be identified, although considerable pattern variability is evident between the subjects and between the different studies (Winter, 1983; Mann, 1980; Elftman, 1940). The patterns and magnitudes appear to be influenced by skill level (Mann, 1980) and running speed (Winter, 1983; Mann, 1980). Inter-subject variability is joint dependent. Winter (1983) reported increased inter-subject JM variability from the ankle to the hip joint. Differences among subjects and studies could be due partially to the individual strategies used for accommodating impact forces and for generating propulsive forces. Therefore, the purpose of the study was to identify inter-subject differences among the lower extremity joint moments to gain a better understanding of the adaptation strategies utilized during the support period

    Vacuum-UV negative photoion spectroscopy of CH3F, CH3Cl and CH3Br

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    Using tunable vacuum-UV radiation from a synchrotron, negative ions are detected by quadrupolar mass spectrometry following photoexcitation of three gaseous halogenated methanes CH3_3X (X = F,Cl,Br). The anions X^-, H^-, CX^-, CHX^- and CH2_2X^- are observed, and their ion yields recorded in the range 8-35 eV. The anions show a linear dependence of signal with pressure, showing that they arise from unimolecular ion-pair dissociation, generically described as AB + hvv \rightarrow A^- + B+^+ (+ neutrals). Absolute cross sections for ion-pair formation are obtained by calibrating the signal intensities with those of F^- from both SF6_6 and CF4_4. The cross sections for formation of X^- + CH3_3+^+ are much greater than for formation of CH2_2X^- + H+^+. In common with many quadrupoles, the spectra of mm/zz 1 (H^-) anions show contributions from all anions, and only for CH3_3Br is it possible to perform the necessary subtraction to obtain the true H^- spectrum. The anion cross sections are normalised to vacuum-UV absorption cross sections to obtain quantum yields for their production. The appearance energies of X^- and CH2_2X^- are used to calculate upper limits to 298 K bond dissociation energies for Do^o (H3_3C-X) and Do^o (XH2_2C-H) which are consistent with literature values. The spectra suggest that most of the anions are formed indirectly by crossing of Rydberg states of the parent molecule onto an ion-pair continuum. The one exception is the lowest-energy peak of F^- from CH3_3F at 13.4 eV, where its width and lack of structure suggest it may correspond to a direct ion-pair transition

    The 1973-1984 Solar Modulation of Cosmic Ray Nuclei

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    As a continuation of the program of solar modulation studies, new measurements were carried out with the cosmic ray telescope on the Earth satellite IMP-8, of the intensity time variations and the energy spectra of galactic cosmic ray protons, helium, carbon and oxygen from 1980 through 1984 including the recent solar maximum. In order to test the applicability of a steady state model of solar modulation during a period which includes times of rapidly changing modulation, these fluxes were equated with the predictions of a conventional model of solar modulation which assumes equilibrium between modulation mechanisms. It is found that for a reasonable range of variations of the diffusion coefficient the model predictions can be made to agree with the measurements at essentially all times during the studied period. The model can account also for the observed hysteresis effects between cosmic rays of different rigidities

    Galactic cosmic ray radial gradients and the anomalous He component near maximum solar modulation and to radii beyond 34 AU from the Sun

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    Radial gradients for relativistic galactic cosmic rays (E 70 MeV) remained nearly constant at approx. 2.5%/AU from 1978-84, which includes the period of maximum solar modulation in 1981-82. For energies 30-70 MeV/n, gradients decreased at solar maximum to values of 1%/AU (protons) and 4%/AU (helium), and appear to be increasing again in 1983-84 toward the values found for solar minimum. The anomalous helium component has not reappeared, either at 1 AU or at Pioneer 10 at R 34 AU

    Prevalence, incidence, primary care burden and medical treatment of angina in Scotland: age, sex and socioeconomic disparities: a population-based study

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    Objective: To examine the epidemiology, primary care burden and treatment of angina in Scotland. Design: Cross-sectional data from primary care practices participating in the Scottish continuous morbidity recording scheme between 1 April 2001 and 31 March 2002. Setting: 55 primary care practices (362 155 patients). Participants: 9508 patients with angina. Results: The prevalence of angina in Scotland was 28/1000 in men and 25/1000 in women (p < 0.05) and increased with age. The prevalence of angina also increased with increasing socioeconomic deprivation from 18/1000 in the least deprived category to 31/1000 in the most deprived group (p < 0.001 for trend). The incidence of angina was higher in men (1.8/1000) than in women (1.4/1000) (p = 0.004) and increased with increasing age and socioeconomic deprivation. Socioeconomically deprived patients (0.48 contacts/patient among the most deprived) were less likely than affluent patients (0.58 contacts/patient among the least deprived) to see their general practitioner on an ongoing basis p = 0.006 for trend). Among men, 52% were prescribed ß blockers, 44% calcium channel blockers, 72% aspirin, 54% statins and 36% angiotensin converting enzyme inhibitors or angiotensin receptor blockers. The corresponding prescription rates for women were 46% (p < 0.001), 41% (p = 0.02), 69% (p < 0.001), 45% (p < 0.001) and 30% (p < 0.001). Among patients < 75 years old 52% were prescribed a β blocker and 58% a statin. The corresponding figures for patients ≥ 75 years were 42% (p < 0.001) and 31% (p < 0.001). Conclusions: Angina is a common condition, more so in men than in women. Socioeconomically deprived patients are more likely to have angina but are less likely to consult their general practitioner. Guideline-recommended treatments for angina are underused in women and older patients. These suboptimal practice patterns, which are worst in older women, are of particular concern, as in Scotland more women (and particularly older women) than men have angina

    Ecological orientations to sociolinguistic scale: Insights from study abroad experiences

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    The sociolinguistics of globalisation, as an emerging paradigm, focuses on the impact of mobility on the linguistic capital of mobile individuals. To understand this, Blommaert advocates a scalar approach to language arguing that some people’s repertoires “will allow mobility while others will not” (2010. The sociolinguistics of globalization. Cambridge: Cambridge University Press: 23) and proposing high scale, low scale orderings. In this paper we introduce an ecological orientation to sociolinguistic scale that challenges the fixity of a high/low scale distinction by conceptually drawing on the notions of flat ontology (Marston et al. 2005. Human geography without scale. Transactions of the Institute of British Geographers 30(4). 416–432) and exchange value (Heller. 2010. The commodification of language. Annual Review of Anthropology 39. 101–114). We do this in relation to Study Abroad (SA) contexts, which offer spaces for investigating how mobility influences the exchange value of individuals’ linguistic repertoires. The study speaks to a broader project in social research which emphasises the agency, subjectivity and criticality of the individual and stresses the complex and rhizomatic nature of social interaction. Drawing on moment analysis (Li. 2011. Moment Analysis and translanguaging space: Discursive construction of identities by multilingual Chinese youth in Britain. Journal of Pragmatics 43. 1222–1235), we examine the experiences of two study abroad students in the UK. These include tellings of critical and reflective moments through which we interpret their experience of how the interplay of language, place and ecology of interaction results in constant, dynamic changes in the exchange value of their English repertoires. Our contribution is to show how an ecological orientation and a flat, rather than stratified, ontology enables insights into language use and globalisation in a way that empowers multilingual, mobile individuals

    Constraints on radiative decay of the 17-keV neutrino from COBE Measurements

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    It is shown that, for a nontrivial radiative decay channel of the 17-keV neutrino, the photons would distort the microwave background radiation through ionization of the universe. The constraint on the branching ratio of such decays from COBE measurements is found to be more stringent than that from other considerations. The limit on the branching ratio in terms of the Compton yy parameter is Bγ<1.5×107(τν1011sec)0.45(y103)1.11h1B_\gamma < 1.5 \times 10^{-7} ({\tau_\nu \over 10^{11} sec})^{0.45} ({y \over 10^{-3}})^{1.11} h^{-1} for an Ω=1,Ωb=0.1\Omega=1, \Omega_b=0.1 universe.Comment: 7 pages. (figures will be sent on request) (To appear in Phys. Rev. D.
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