Social Networking in Academic Libraries: The Possibilities and the Concerns

The goal of this article is to examine the use of the major social networking tools in academic libraries in the United States. Since college students are heavy users of social networking, such efforts provide academic libraries with outreach possibilities to students who do not use the physical library. The paper also examines the concerns about their use both from students and within the academic library

A Common Eider × King Eider Hybrid Captured on the Kent Peninsula, Nunavut

On 25 June 2002, we captured and recorded measurements of a male common eider (Somateria mollissima) × king eider (S. spectabilis) hybrid at Nauyak Lake, on the Kent Peninsula, Nunavut. This is the first documented capture of a hybrid eider, rarely observed in North America. Structural body measurements and mass of the hybrid were intermediate compared to those of Pacific common eiders (S. m. v-nigrum) at the same study site and king eiders at a nearby study site during the same time of year. The plumage of the captured hybrid had characteristics of both parent species. Mate pairing on overlapping spring staging or wintering areas of common and king eiders may occasionally result in hybrid offspring.Le 25 juin 2002, nous avons capturé un hybride composé d’un eider à duvet (Somateria mollissima) × un eider à tête grise (S. spectabilis) au lac Nauyak, dans la péninsule de Kent, au Nunavut, puis nous avons pris note de ses mesures. Il s’agit de la première capture répertoriée d’un eider hybride, ce qui est rarement observé en Amérique du Nord. Les mesures et la masse de la structure corporelle de l’hybride étaient intermédiaires comparativement à celles des eiders à duvet du Pacifique (S. m. v-nigrum) du même lieu d’étude et à celles des eiders à tête grise d’un lieu d’étude avoisinant pendant la même période de l’année. Le plumage de l’hybride que nous avons capturé présentait des caractéristiques des deux espèces. Il arrive parfois que les accouplements aux haltes migratoires du printemps ou aux aires d’hivernage partagées par les eiders à duvet et les eiders à tête grise donnent lieu à une progéniture hybride

Gender Diferences in Heart Failure Self-Care: A Multinational Cross-Sectional Study

Background Despite a common view that women are better at self-care, there is very little evidence to support or challenge this perspective in the heart failure (HF) population. Objective The purpose of this study was to determine if there are cross-cultural gender differences in self-reported HF self-care and to describe gender differences in the determinants of HF self-care. Design, setting, and participants A secondary analysis was completed of cross-sectional study data collected on 2082 adults with chronic HF from the United States, Australia and Thailand. Methods Comparisons were made between men and women regarding self-care maintenance, management and confidence as assessed by the Self-Care of Heart Failure Index, as well as the proportion of subjects engaged in adequate self-care. Multivariate comparisons were made to determine if gender explained sufficient variance in HF self-care and the likelihood of reporting adequate self-care, controlling for nine model covariates. Results The sample was comprised of 1306 men and 776 women. Most (73.5%) had systolic or mixed systolic and diastolic HF and 45% had New York Heart Association class III or IV HF. Although small and clinically insignificant gender differences were found in self-care maintenance, gender was not a determinant of any aspect of HF self-care in multivariate models. Married women were 37% less likely to report adequate self-care maintenance than unmarried women. Comorbidities only influenced the HF self-care of men. Being newly diagnosed with HF also primarily affected men. Patients with diastolic HF (predominantly women) had poorer self-care maintenance and less confidence in self-care. Conclusion Differences in HF self-care are attributable to factors other than gender; however, there are several gender-specific determinants of HF self-care that help identify patients at risk for practicing poor self-care

Multi-point study of the energy release and transport in the 28 March 2022, M4-flare using STIX, EUI, and AIA during the first Solar Orbiter nominal mission perihelion

We present a case study of an M4-class flare on 28 March 2022, near Solar Orbiter's first science perihelion (0.33 AU). Solar Orbiter was 83.5{\deg} west of the Sun-Earth line, making the event appear near the eastern limb, while Earth-orbiting spacecraft observed it near the disk center. The timing and location of the STIX X-ray sources were related to the plasma evolution observed in the EUV by the Extreme Ultraviolet Imager (EUI) on Solar Orbiter and the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory, and to the chromospheric response observed in 1600 {\AA} by AIA. We performed differential emission measure (DEM) analysis to further characterize the flaring plasma at different subvolumes. The pre-flare magnetic field configuration was analyzed using a nonlinear force-free (NLFF) extrapolation. In addition to the two classical hard X-ray (HXR) footpoints at the ends of the flaring loops, later in the event we observe a nonthermal HXR source at one of the anchor points of the erupting filament. The evolution of the AIA 1600~{\AA} footpoints indicates that this change in footpoint location represents a discontinuity in an otherwise continuous westward motion of the footpoints throughout the flare. The NLFF extrapolation suggests that strongly sheared field lines close to, or possibly even part of, the erupting filament reconnected with a weakly sheared arcade during the first HXR peak. The remainder of these field lines reconnected later in the event, producing the HXR peak at the southern filament footpoint. Our results show that the reconnection between field lines with very different shear in the early phase of the flare plays a crucial role in understanding the motion of the HXR footpoint during later parts of the flare. This generalizes simpler models, such as whipping reconnection, which only consider reconnection propagating along uniformly sheared arcades

Identifying the energy release site in a solar microflare with a jet

Context. One of the main science questions of the Solar Orbiter and Parker Solar Probe missions deals with understanding how electrons in the lower solar corona are accelerated and how they subsequently access interplanetary space. Aims. We aim to investigate the electron acceleration and energy release sites as well as the manner in which accelerated electrons access the interplanetary space in the case of the SOL2021-02-18T18:05 event, a GOES A8 class microflare associated with a coronal jet. Methods. This study takes advantage of three different vantage points, Solar Orbiter, STEREO-A, and Earth, with observations drawn from eight different instruments, ranging from radio to X-ray. Multi-wavelength timing analysis combined with UV/EUV imagery and X-ray spectroscopy by Solar Orbiter/STIX (Spectrometer/Telescope for Imaging X-rays) is used to investigate the origin of the observed emission during different flare phases. Results. The event under investigation satisfies the classical picture of the onset time of the acceleration of electrons coinciding with the jet and the radio type III bursts. This microflare features prominent hard X-ray (HXR) nonthermal emission down to at least 10 keV and a spectrum that is much harder than usual for a microflare with γ = 2.9 ± 0.3. From Eartha's vantage point, the microflare is seen near the limb, revealing the coronal energy release site above the flare loop in EUV, which, from STIX spectroscopic analysis, turns out to be hot (i.e., at roughly the same temperature of the flare). Moreover, this region is moving toward higher altitudes over time (∼30akmas-1). During the flare, the same region spatially coincides with the origin of the coronal jet. Three-dimensional (3D) stereoscopic reconstructions of the propagating jet highlight that the ejected plasma moves along a curved trajectory. Conclusions. Within the framework of the interchange reconnection model, we conclude that the energy release site observed above-The-loop corresponds to the electron acceleration site, corroborating that interchange reconnection is a viable candidate for particle acceleration in the low corona on field lines open to interplanetary space

The calcium isotopic composition of carbonate hardground cements: A new record of changes in ocean chemistry?

Reconstructing changes in the calcium isotopic composition (δ44Ca) of the ocean over Earth history has been challenging. This difficulty is due to the large range of calcium isotope fractionation factors during mineral precipitation and the potential for overwriting the initial δ44Ca of minerals during shallow marine diagenesis. We present a new δ44Ca record measured in carbonate hardground cements, an inorganic carbonate-mineral precipitate that rapidly forms at or near the sediment-water interface. The range in the δ44Ca for any particular carbonate hardground cements is between 0.05 and 0.56‰. In some cases, the progressive increase in the δ44Ca during precipitation can be observed, consistent with precipitation in a ‘closed-system’. Our data show an average calcium isotope fractionation during carbonate hardground cement precipitation that is −0.57 ± 0.27‰, similar to the calcium isotope fractionation factor for inorganic calcite precipitates in previous laboratory and modelling studies, and closer to what is considered a kinetic end member calcium isotope fractionation than growth at equilibrium. This is consistent with the rapid carbonate mineral precipitation expected for carbonate hardground cements. Our δ44Ca record over the Phanerozoic is similar to other calcium-bearing mineral records over the same time interval, with average δ44Ca becoming lower going back in time by about 0.5 to 0.7‰. Our results add further support for the evolution of seawater δ44Ca over time, and we discuss the possible causes of these changes with suggestions for future studies

The UV radiation from z∼2.5z\sim2.5 radio galaxies: Keck spectropolarimetry of 4C 23.56 and 4C 00.54

We present the results of deep spectropolarimetry of two powerful radio galaxies at $z\sim2.5$ (4C 00.54 and 4C 23.56) obtained with the W.M. Keck II 10m telescope, aimed at studying the relative contribution of the stellar and non-stellar components to the ultraviolet continuum. Both galaxies show strong linear polarization of the continuum between rest-frame $\sim$1300-2000~\AA, and the orientation of the electric vector is perpendicular to the main axis of the UV continuum. In this sense, our objects are like most 3C radio galaxies at $z\sim1$. The total flux spectra of 4C 00.54 and 4C 23.56 do not show the strong P-Cygni absorption features or the photospheric absorption lines expected when the UV continuum is dominated by young and massive stars. The only features detected can be ascribed to interstellar absorptions by SiII, CII and OI. Our results are similar to those for 3C radio galaxies at lower $z$, suggesting that the UV continuum of powerful radio galaxies at $z\sim2.5$ is still dominated by non-stellar radiation, and that young massive stars do not contribute more than $\approx$50% to the total continuum flux at 1500~\AA.Comment: 17 pages, ApJ Letters, in press, 5 figures, 2 table