Two-gap superconductivity in single crystal Lu2_2Fe3_3Si5_5 from penetration depth measurements

Single crystal of Lu$_2$Fe$_3$Si$_5$ was studied with the tunnel-diode resonator technique in Meissner and mixed states. Temperature dependence of the superfluid density provides strong evidence for the two-gap superconductivity with almost equal contributions from each gap of magnitudes $\Delta_1/k_BT_c=1.86$ and $\Delta_1/k_BT_c=0.54$. In the vortex state, pinning strength shows unusually strong temperature dependence and is non-monotonic with the magnetic field (peak effect). The irreversibility line is sharply defined and is quite distant from the $H_{c2}(T)$, which hints on to enhanced vortex fluctuations in this two-gap system. Altogether our findings provide strong electromagnetic - measurements support to the two-gap superconductivity in Lu$_2$Fe$_3$Si$_5$ previously suggested from specific heat measurements

Generational differences in practice site selection criteria amongst primary care physicians.

Background and Objectives: Generational differences are often viewed as shaping the overall attitudes and actions of different age cohorts. It is essential to understand the motivations and generational differences in primary care physicians for efforts to recruit, retain, and educate the future physician workforce. Determining what factors most influence different generations of primary care physicians when choosing a practice site is essential to build our future primary care system. This study examined generational differences in the factors that attracted primary care physicians to their current practice. Methods: A survey instrument was mailed to all active members of the North Carolina Medical Board who listed their primary occupation as a primary care specialty. The survey consisted of 24 demographic questions regarding personal and practice variables and a list of 21 reasons for choosing a practice location measured on a 7-point Likert type scale. A total of 975 surveys were returned and usable for the final analysis, for a return rate of 34.5%. Data were analyzed using regression and correlation procedures to determine attitudes of each generation and factors that significantly influenced responses. Results: While slight differences between generations did exist, the overall choices for choosing a site remained stable across generations. Personality of the practice, on-call responsibilities, ability to practice comprehensive care, and location were deemed the most important factors for all generations. Differences between various demographic groups and Family Medicine versus other primary care specialties were minor with very little alteration of the top ten items being seen between groups. Conclusion: This study indicated that there were few differences between generations regarding primary reasons for choosing a practice site. In addition, factors remained remarkably similar across different specialties, family situations, genders, and ethnic groups. Several of the top reasons that primary care physicians indicate are the most important for site selection were also potentially modifiable, such as on-call responsibilities, practice personality, and ability to practice comprehensive care. Managers, clinicians, and educators can potentially utilize this information to better prepare and recruit current and future generations of primary care physicians.ECU Open Access Publishing Fun

Transition to Long Range Magnetic Order in the Highly Frustrated Insulating Pyrochlore Antiferromagnet Gd_2Ti_2O_7

Experimental evidence from measurements of the a.c. and d.c. susceptibility, and heat capacity data show that the pyrochlore structure oxide, Gd_2Ti_2O_7, exhibits short range order that starts developing at 30K, as well as long range magnetic order at $T\sim 1$K. The Curie-Weiss temperature, $\theta_{CW}$ = -9.6K, is largely due to exchange interactions. Deviations from the Curie-Weiss law occur below $\sim$10K while magnetic heat capacity contributions are found at temperatures above 20K. A sharp maximum in the heat capacity at $T_c=0.97$K signals a transition to a long range ordered state, with the magnetic specific accounting for only $\sim$ 50% of the magnetic entropy. The heat capacity above the phase transition can be modeled by assuming that a distribution of random fields acts on the $^8S_{7/2}$ ground state for Gd$^{3+}$. There is no frequency dependence to the a.c. susceptibility in either the short range or long range ordered regimes, hence suggesting the absence of any spin-glassy behavior. Mean field theoretical calculations show that no long range ordered ground state exists for the conditions of nearest-neighbor antiferromagnetic exchange and long range dipolar couplings. At the mean-field level, long range order at various commensurate or incommensurate wave vectors is found only upon inclusion of exchange interactions beyond nearest-neighbor exchange and dipolar coupling. The properties of Gd$_2Ti_2O_7 are compared with other geometrically frustrated antiferromagnets such as the Gd_3Ga_5O_{12} gadolinium gallium garnet, RE_2Ti_2O_7 pyrochlores where RE = Tb, Ho and Tm, and Heisenberg-type pyrochlore such as Y_2Mo_2O_7, Tb_2Mo_2O_7, and spinels such as ZnFe_2O_4Comment: Letter, 6 POSTSCRIPT figures included. (NOTE: Figure 5 is not included --) To appear in Physical Review B. Contact: [email protected]

Actinopolyspora algeriensis sp. nov., a novel halophilic actinomycete isolated from a Saharan soil

A halophilic actinomycete strain designated H19T, was isolated from a Saharan soil in the Bamendil region (Ouargla province, South Algeria) and was characterized taxonomically by using a polyphasic approach. The morphological and chemotaxonomic characteristics of the strain were consistent with those of members of the genus Actinopolyspora, and 16S rRNA gene sequence analysis confirmed that strain H19T was a novel species of the genus Actinopolyspora. DNA–DNA hybridization value between strain H19T and the nearest Actinopolyspora species, A. halophila, was clearly below the 70 % threshold. The genotypic and phenotypic data showed that the organism represents a novel species of the genus Actinopolyspora for which the name Actinopolyspora algeriensis sp. nov. is proposed, with the type strain H19T (= DSM 45476T = CCUG 62415T)

Generational differences in practice site selection criteria amongst primary care physicians.

ABSTRACT Background and Objectives: Generational differences are often viewed as shaping the overall attitudes and actions of different age cohorts. It is essential to understand the motivations and generational differences in primary care physicians for efforts to recruit, retain, and educate the future physician workforce. Determining what factors most influence different generations of primary care physicians when choosing a practice site is essential to build our future primary care system. This study examined generational differences in the factors that attracted primary care physicians to their current practice. Methods: A survey instrument was mailed to all active members of the North Carolina Medical Board who listed their primary occupation as a primary care specialty. The survey consisted of 24 demographic questions regarding personal and practice variables and a list of 21 reasons for choosing a practice location measured on a 7-point Likert type scale. A total of 975 surveys were returned and usable for the final analysis, for a return rate of 34.5%. Data were analyzed using regression and correlation procedures to determine attitudes of each generation and factors that significantly influenced responses. Results: While slight differences between generations did exist, the overall choices for choosing a site remained stable across generations. Personality of the practice, on-call responsibilities, ability to practice comprehensive care, and location were deemed the most important factors for all generations. Differences between various demographic groups and Family Medicine versus other primary care specialties were minor with very little alteration of the top ten items being seen between groups. Conclusion: This study indicated that there were few differences between generations regarding primary reasons for choosing a practice site. In addition, factors remained remarkably similar across different specialties, family situations, genders, and ethnic groups. Several of the top reasons that primary care physicians indicate are the most important for site selection were also potentially modifiable, such as on-call responsibilities, practice personality, and ability to practice comprehensive care. Managers, clinicians, and educators can potentially utilize this information to better prepare and recruit current and future generations of primary care physicians. Keywords: site selection, recruiting, generational differenc

40-Gb/s DWDM free-space optical transmission link over 4.4 km

We simultaneously transmit 16 separate 2.5 Gb/s wavelength data channels, with a 200 Ghz channel spacing, error-free, over a horizontal free space distance of 4.4 km. We believe this result represents the largest bandwidth transmitted at one time over such a distance, without the use of optical transmission fiber

An Analysis on Spatiotemporal Variations of Soil and Vegetation Moisture from a 29 year Satellite Derived Dataset over Mainland Australia

The spatiotemporal behavior of soil and vegetation moisture over mainland Australia was analyzed using passive microwave observations by four satellites going back to late 1978. Differences in measurement specifications prevented merging the data directly. A continuous product was developed for Australia by scaling percentiles of the cumulative moisture distribution within each grid cell to the percentiles of a reference sensor. The coefficient of correlation and root-mean-square error between rescaled values and the reference generally suggest good agreement. Using the merged data product, a strong El Nino-Southern Oscillation signal in near-surface hydrology across Australia was confirmed. Spatial patterns of trends in annual averages show that western and northwestern Australia have experienced an increase in vegetation moisture content, while the east and southeast experienced a decrease. Soil moisture showed a similar spatial pattern but with larger regions experiencing a decrease. This could be explained by decreasing rainfall and increasing potential evapotranspiration during the extended winter period (May-September). The results give us reasonable confidence in the time series of soil and vegetation moisture derived by the scaling method developed in this study. Development of a global data set along these lines should enable better estimation of hydrological variables and should increase understanding of the impacts of ocean circulations on terrestrial hydrology and vegetation dynamics. Copyright 2009 by the American Geophysical Union

The use of the TCNQF₄^2-dianion in the spontaneous redox formation of [Fe^III(L^-)₂][TCNQF₄•-]

The reaction of [FeII(L •)2](BF4)2 with Li2TCNQF4 results in the formation of [FeIII(L-)2][TCNQF4•-] (1) where L• is the radical ligand, 4,4-dimethyl-2,2-di(2-pyridyl)oxazolidine-N-oxide and TCNQF4 is 2,3,5,6-Tetrafluoro-7,7,8,8-tetracyano-quinodimethane. This has been characterised by x-ray diffraction, Raman and Fourier-transform infra-red (FTIR) spectroscopy, variable temperature magnetic susceptibility, Mössbauer spectroscopy and electrochemistry. X-ray diffraction studies, magnetic susceptibility measurements and Raman and FTIR spectroscopy suggest the presence of low-spin FeIII ion, the anionic form (L-­) of the ligand and the anionic radical form of TCNQF4; TCNQF4•-. Li2TCNQF4 reduces the [FeII(L•)2]2+ dication which undergoes a reductively induced oxidation to form the [FeIII(L-)2]+ monocation resulting in the formation of [FeIII(L-)2][TCNQF4•-] (1), the electrochemistry of which revealed four well-separated, diffusion controlled, one-electron, reversible processes. Mössbauer spectroscopy and electrochemical measurements suggest the presence of a minor second species, likely to be [FeII(L•)2][TCNQF42-]