1,371 research outputs found

    Concentrations of Insulin-Like Growth Factor-I in Blood and Ovarian Follicular Fluid of Cattle Selected for Twins

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    Recent studies have implicated insulin-like growth factor I (IGF-I) as an intraovarian regulator of follicular growth and differentiation. Therefore, we investigated the possibility that cattle selected for twin births may have increased concentrations of IGF-I within the ovarian follicle and(or) in peripheral blood. The estrous cycles of 14 cows with histories of producing twins and 12 control monotocous cows were synchronized with 35 mg of prostaglandin F2α (PGF2α). Blood and follicular fluid were collected 48-50 h post-administration of PGF2α. (follicular phase of the estrous cycle). Concentrations of IGF-I were measured by RJA after acid-ethanol treatment of serum or follicular fluid. Twin-producing cows had a greater (p \u3c 0.05) number of large (\u3e4 mm) follicles and 47% greater (p \u3c 0.05) concentrations of IGF-I in peripheral blood than control cows. Cattle selected for high twinning frequency also had greater (p \u3c 0.05) concentrations of IGF-I (±SE) in the two largest follicles than control (unselected) cows (327 ± 28 vs. 243 ± 29 ng/ml). IGF-I concentrations in pooled small (1-3.9 mm) follicles were less (p \u3c 0.05) than in large follicles but did not differ between control and twin-producing cattle. In addition, the percentage of IGF-I concentrations measured in follicular fluid to that of serum was lower (P \u3c 0.05) in small follicles than in large follicles, and was greater (p \u3c0.05) in large follicles of control (93.2 ± 5.3%) than twin-producing (76.2 ± 4.4%) cattle. Moreover, concentrations of IGF-I in serum and follicular fluid were correlated positively (r = 0.69, p \u3c 0.01). Concentrations of estradiol and progesterone in follicular fluid of small or large follicles did not differ between control and twin-producing cattle. Collectively, the present study provides evidence suggesting that natural twinning in cattle is associated with increased concentrations of IGF-I in both blood and follicular fluid. These data are consistent with the hypothesis that IGF-I plays a role in the regulation of folliculogenesis and is a mediator of a genetic component of multiple ovulations in cattle

    Electronic and structural properties of vacancies on and below the GaP(110) surface

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    We have performed total-energy density-functional calculations using first-principles pseudopotentials to determine the atomic and electronic structure of neutral surface and subsurface vacancies at the GaP(110) surface. The cation as well as the anion surface vacancy show a pronounced inward relaxation of the three nearest neighbor atoms towards the vacancy while the surface point-group symmetry is maintained. For both types of vacancies we find a singly occupied level at mid gap. Subsurface vacancies below the second layer display essentially the same properties as bulk defects. Our results for vacancies in the second layer show features not observed for either surface or bulk vacancies: Large relaxations occur and both defects are unstable against the formation of antisite vacancy complexes. Simulating scanning tunneling microscope pictures of the different vacancies we find excellent agreement with experimental data for the surface vacancies and predict the signatures of subsurface vacancies.Comment: 10 pages, 6 figures, Submitted to Phys. Rev. B, Other related publications can be found at http://www.rz-berlin.mpg.de/th/paper.htm

    Evaluating case studies of community-oriented integrated care.

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    This paper summarises a ten-year conversation within London Journal of Primary Care about the nature of community-oriented integrated care (COIC) and how to develop and evaluate it. COIC means integration of efforts for combined disease-treatment and health-enhancement at local, community level. COIC is similar to the World Health Organisation concept of a Community-Based Coordinating Hub - both require a local geographic area where different organisations align their activities for whole system integration and develop local communities for health. COIC is a necessary part of an integrated system for health and care because it enables multiple insights into 'wicked problems', and multiple services to integrate their activities for people with complex conditions, at the same time helping everyone to collaborate for the health of the local population. The conversation concludes seven aspects of COIC that warrant further attention

    Integrable lattice equations with vertex and bond variables

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    We present integrable lattice equations on a two dimensional square lattice with coupled vertex and bond variables. In some of the models the vertex dynamics is independent of the evolution of the bond variables, and one can write the equations as non-autonomous "Yang-Baxter maps". We also present a model in which the vertex and bond variables are fully coupled. Integrability is tested with algebraic entropy as well as multidimensional consistencyComment: 15 pages, remarks added, other minor change

    The staircase method: integrals for periodic reductions of integrable lattice equations

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    We show, in full generality, that the staircase method provides integrals for mappings, and correspondences, obtained as traveling wave reductions of (systems of) integrable partial difference equations. We apply the staircase method to a variety of equations, including the Korteweg-De Vries equation, the five-point Bruschi-Calogero-Droghei equation, the QD-algorithm, and the Boussinesq system. We show that, in all these cases, if the staircase method provides r integrals for an n-dimensional mapping, with 2r<n, then one can introduce q<= 2r variables, which reduce the dimension of the mapping from n to q. These dimension-reducing variables are obtained as joint invariants of k-symmetries of the mappings. Our results support the idea that often the staircase method provides sufficiently many integrals for the periodic reductions of integrable lattice equations to be completely integrable. We also study reductions on other quad-graphs than the regular 2D lattice, and we prove linear growth of the multi-valuedness of iterates of high-dimensional correspondences obtained as reductions of the QD-algorithm.Comment: 40 pages, 23 Figure

    Safety and Feasibility of Thoracic Malignancy Surgery During the COVID-19 Pandemic

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    Background: The coronavirus disease 2019 (COVID-19) pandemic has decreased surgical activity, particularly in the field of oncology, because of the suspicion of a higher risk of COVID-19–related severe events. This study aimed to investigate the feasibility and safety of thoracic cancer surgery in the most severely affected European and Canadian regions during the COVID-19 pandemic. Methods: The study investigators prospectively collected data on surgical procedures for malignant thoracic diseases from January 1 to April 30, 2020. The study included patients from 6 high-volume thoracic surgery departments: Nancy and Strasbourg (France), Freiburg (Germany), Milan and Turin (Italy), and Montreal (Canada). The centers involved in this research are all located in the most severely affected regions of those countries. An assessment of COVID-19–related symptoms, polymerase chain reaction (PCR)–confirmed COVID-19 infection, rates of hospital and intensive care unit admissions, and death was performed for each patient. Every deceased patient was tested for COVID-19 by PCR. Results: In the study period, 731 patients who underwent 734 surgical procedures were included. In the whole cohort, 9 cases (1.2%) of COVID-19 were confirmed by PCR, including 5 in-hospital contaminants. Four patients (0.5%) needed readmission for oxygen requirements. In this subgroup, 2 patients (0.3%) needed intensive care unit and mechanical ventilatory support. The total number of deaths in the whole cohort was 22 (3%). A single death was related to COVID-19 (0.14%). Conclusions: Maintaining surgical oncologic activity in the era of the COVID-19 pandemic seems safe and feasible, with very low postoperative morbidity or mortality. To continue to offer the best care to patients who do not have COVID-19, reports on other diseases are urgently needed

    C Wright Mills, power and the power elites ? a reappraisal

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    This paper revisits and presents a critical appraisal of Mills's analysis of power and the power elite. There are signs of a revival of interest in Mills, but recent commentators have shown little interest in the intellectual, social or political context of his analysis. Setting Mills's thesis in its historical context, we consider an element of his project that has been particularly neglected in recent discussion: Mills's search for possible ways of redistributing power and his attempt to forge an ethico-political stance. Reflecting on recent discussion of contemporary elite formations, we comment on what critics might take from Mills in our own time in relation to the analysis of elites and the politics of critical management studies

    Noise storm continua: power estimates for electron acceleration

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    We use a generic stochastic acceleration formalism to examine the power LinL_{\rm in} (ergs−1{\rm erg s^{-1}}) input to nonthermal electrons that cause noise storm continuum emission. The analytical approach includes the derivation of the Green's function for a general second-order Fermi process, and its application to obtain the particular solution for the nonthermal electron distribution resulting from the acceleration of a Maxwellian source in the corona. We compare LinL_{\rm in} with the power LoutL_{\rm out} observed in noise storm radiation. Using typical values for the various parameters, we find that Lin∌1023−26L_{\rm in} \sim 10^{23-26} ergs−1{\rm erg s^{-1}}, yielding an efficiency estimate η≥Lout/Lin\eta \equiv L_{\rm out}/L_{\rm in} in the range 10^{-10} \lsim \eta \lsim 10^{-6} for this nonthermal acceleration/radiation process. These results reflect the efficiency of the overall process, starting from electron acceleration and culminating in the observed noise storm emission.Comment: Accepted for publication in Solar Physic
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