55,716 research outputs found

    Earth radiation budget measurements from satellites and their interpretation for climate modeling and studies

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    The annual and seasonal averaged Earth atmosphere radiation budgets derived from the most complete set of satellite observations available are presented. The budgets were derived from a composite of 48 monthly mean radiation budget maps. Annually and seasonally averaged radiation budgets are presented as global averages and zonal averages. The geographic distribution of the various radiation budget quantities is described. The annual cycle of the radiation budget was analyzed and the annual variability of net flux was shown to be largely dominated by the regular semi and annual cycles forced by external Earth-Sun geometry variations. Radiative transfer calculations were compared to the observed budget quantities and surface budgets were additionally computed with particular emphasis on discrepancies that exist between the present computations and previous surface budget estimates

    A study of the semiannual density variation in the upper atmosphere from 1958 to 1966, based on satellite drag analysis

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    Semiannual density variation in upper atmosphere from 1958 to 1966 based on satellite drag analysi

    Riding without a saddle

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    This paper describes a qualitative study taking place into (un)safe sex practices by gay men. The paper seeks to understand the initiation of sexual practice from a loyalty perspective in an effort to ascertain if established behaviours (loyalty) may be shifted over time. To this end, a natural history embedded within a narrative enquiry approach has been adopted. Preliminary outcomes provide some insights into urgent priorities for social marketing campaigns aiming to decrease the spread of HIV/AIDS in gay populations

    Detection of the United States Neisseria meningitidis urethritis clade in the United Kingdom, August and December 2019 - emergence of multiple antibiotic resistance calls for vigilance.

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    Since 2015 in the United States (US), the US Neisseria meningitidis urethritis clade (US_NmUC) has caused a large multistate outbreak of urethritis among heterosexual males. Its 'parent' strain caused numerous outbreaks of invasive meningococcal disease among men who have sex with men in Europe and North America. We highlight the arrival and dissemination of US_NmUC in the United Kingdom and the emergence of multiple antibiotic resistance. Surveillance systems should be developed that include anogenital meningococci

    Tuning Rashba and Dresselhaus spin-orbit couplings: Effects on singlet and triplet condensation with Fermi atoms

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    We investigate the pair condensation of a two-spin-component Fermi gas in the presence of both Rashba and Dresselhaus spin-orbit couplings. We calculate the condensate fraction in the BCS-BEC crossover both in two and in three dimensions by taking into account singlet and triplet pairings. These quantities are studied by varying the spin-orbit interaction from the case with the only Rashba to the equal-Rashba-Dresselhaus one. We find that, by mixing the two couplings, the singlet pairing decreases while the triplet pairing is suppressed in the BCS regime and increased in the BEC regime, both in two and three dimensions. At fixed spin-orbital strength, the greatest total condensate fraction is obtained when only one coupling (only Rashba or only Dresselhaus) is present.Comment: 9 pages, 6 figures, final versio

    Demographic growth and the distribution of language sizes

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    It is argued that the present log-normal distribution of language sizes is, to a large extent, a consequence of demographic dynamics within the population of speakers of each language. A two-parameter stochastic multiplicative process is proposed as a model for the population dynamics of individual languages, and applied over a period spanning the last ten centuries. The model disregards language birth and death. A straightforward fitting of the two parameters, which statistically characterize the population growth rate, predicts a distribution of language sizes in excellent agreement with empirical data. Numerical simulations, and the study of the size distribution within language families, validate the assumptions at the basis of the model.Comment: To appear in Int. J. Mod. Phys. C (2008

    Mandarin Market Segments Based on Consumer Sensory Evaluations

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    Ninety-five consumers in seven grocery stores tasted unidentified peeled sections of three mandarins (a tangerine, a satsuma, and a clementine), and provided demographic and purchase information. Forty-four percent of the respondents preferred tangerines, 34 percent satsumas, and 22 percent clementines. The probability of preferring each of type of mandarin was estimated from internal quality analysis of paired samples, as well as from demographic and purchase responses. Model simulations were used to recommend harvest standards for satsumas based on Brix-to-acid ratios.Demand and Price Analysis, Food Consumption/Nutrition/Food Safety,

    Angular dependence of the magnetization of isotropic superconductors: which is the vortex direction?

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    We present studies of the dc magnetization of thin platelike samples of the isotropic type II superconductor PbTl(10%), as a function of the angle between the normal to the sample and the applied magnetic field H{\bf H}. We determine the magnetization vector M{\bf M} by measuring the components both parallel and normal to H{\bf H} in a SQUID magnetometer, and we further decompose it in its reversible and irreversible contributions. The behavior of the reversible magnetization is well understood in terms of minimization of the free energy taking into account geometrical effects. In the mixed state at low fields, the dominant effect is the line energy gained by shortening the vortices, thus the flux lines are almost normal to the sample surface. Due to the geometrical constrain, the irreversible magnetization Mirr{\bf M}_{irr} remains locked to the sample normal over a wide range of fields and orientations, as already known. We show that in order to undestand the angle and field dependence of the modulus of Mirr{\bf M}_{irr}, which is a measure of the vortex pinning, and to correctly extract the field dependent critical current density, the knowledge of the modulus and orientation of the induction field B{\bf B} is required.Comment: 11 pages, 6 figure
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