430 research outputs found

    Importance of thermophilous habitats for protection of wild bees (Apiformes)

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    Research on wild bees (Apiformes) was conducted in the Lower Oder Valley (NW Poland) at Natura 2000 sites near the border between Poland and Germany. The analysis involved 3 landscape types with xerothermic and sandy grasslands, differing in the proportion of woody vegetation. In total, we collected there 4158 specimens of Apiformes, representing 180 species. We have proved that mid-forest grasslands with a high proportion of thermophilous broad-leaved forests and xerothermic shrub communities are equally attractive to wild bees as open habitats (sandy grasslands, xerothermic grasslands/heaths). We observed varied responses of wild bee species with specific functional characteristics to increasing proportion of woody vegetation. The grasslands surrounded by forests were characterized by the highest number of cleptoparasitic species. In contrast, solitary and social bee species preferred forest-steppe habitats. However, in open habitats, solitary bees were the most abundant. Moreover, open habitats were distinguished by the highest number and abundance of rare species. Active protection of thermophilous grasslands is crucial for biodiversity conservation, also with respect to the natural resources of Apiformes. Preservation of biodiversity in threatened xerothermic and sandy grasslands should be one of the key objectives of nature conservation in European countries. Currently, more and more actions are undertaken to improve their condition and to restore those particularly valuable and threatened habitat types

    The Croatian Health Survey ā€“ Patient\u27s Satisfaction with Medical Service in Primary Health Care in Croatia

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    The aim of the study was to investigate patient satisfaction with nurses and general practice organization in Croatia. A total of 2,252 patients 18 years of age and over from 47 randomly selected general practices were included in the study. 72.1% of patients were satisfied with nurses and general practice organization. Older and less educated patients were generally more satisfied. Patients were more pleased with nursesā€™ behavior (81.9%) than with practice organization (62.3%). Factor analysis revealed two underlying discriminates of patient satisfaction ā€“ Ā»positive attitude towards the nurseĀ« and Ā»inaccessibility of practiceĀ«. The former discriminate emphasized a great potential of nursing, which should be taken into consideration in the transformation of health care system in Croatia

    Structure and energetics of the Si-SiO_2 interface

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    Silicon has long been synonymous with semiconductor technology. This unique role is due largely to the remarkable properties of the Si-SiO_2 interface, especially the (001)-oriented interface used in most devices. Although Si is crystalline and the oxide is amorphous, the interface is essentially perfect, with an extremely low density of dangling bonds or other electrically active defects. With the continual decrease of device size, the nanoscale structure of the silicon/oxide interface becomes more and more important. Yet despite its essential role, the atomic structure of this interface is still unclear. Using a novel Monte Carlo approach, we identify low-energy structures for the interface. The optimal structure found consists of Si-O-Si "bridges" ordered in a stripe pattern, with very low energy. This structure explains several puzzling experimental observations.Comment: LaTex file with 4 figures in GIF forma

    The Green Bank Northern Celestial Cap Pulsar Survey - I: Survey Description, Data Analysis, and Initial Results

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    We describe an ongoing search for pulsars and dispersed pulses of radio emission, such as those from rotating radio transients (RRATs) and fast radio bursts (FRBs), at 350 MHz using the Green Bank Telescope. With the Green Bank Ultimate Pulsar Processing Instrument, we record 100 MHz of bandwidth divided into 4,096 channels every 81.92 Ī¼s\mu s. This survey will cover the entire sky visible to the Green Bank Telescope (Ī“>āˆ’40āˆ˜\delta > -40^\circ, or 82% of the sky) and outside of the Galactic Plane will be sensitive enough to detect slow pulsars and low dispersion measure (<<30 pcā€‰cmāˆ’3\mathrm{pc\,cm^{-3}}) millisecond pulsars (MSPs) with a 0.08 duty cycle down to 1.1 mJy. For pulsars with a spectral index of āˆ’-1.6, we will be 2.5 times more sensitive than previous and ongoing surveys over much of our survey region. Here we describe the survey, the data analysis pipeline, initial discovery parameters for 62 pulsars, and timing solutions for 5 new pulsars. PSR J0214++5222 is an MSP in a long-period (512 days) orbit and has an optical counterpart identified in archival data. PSR J0636++5129 is an MSP in a very short-period (96 minutes) orbit with a very low mass companion (8 MJM_\mathrm{J}). PSR J0645++5158 is an isolated MSP with a timing residual RMS of 500 ns and has been added to pulsar timing array experiments. PSR J1434++7257 is an isolated, intermediate-period pulsar that has been partially recycled. PSR J1816++4510 is an eclipsing MSP in a short-period orbit (8.7 hours) and may have recently completed its spin-up phase.Comment: 18 pages, 10 figures, 5 tables, accepted by Ap

    The Green Bank Northern Celestial Cap Pulsar Survey II: The Discovery and Timing of Ten Pulsars

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    We present timing solutions for ten pulsars discovered in 350 MHz searches with the Green Bank Telescope. Nine of these were discovered in the Green Bank Northern Celestial Cap survey and one was discovered by students in the Pulsar Search Collaboratory program in analysis of drift-scan data. Following discovery and confirmation with the Green Bank Telescope, timing has yielded phase-connected solutions with high precision measurements of rotational and astrometric parameters. Eight of the pulsars are slow and isolated, including PSR J0930āˆ’-2301, a pulsar with nulling fraction lower limit of āˆ¼\sim30\% and nulling timescale of seconds to minutes. This pulsar also shows evidence of mode changing. The remaining two pulsars have undergone recycling, accreting material from binary companions, resulting in higher spin frequencies. PSR J0557āˆ’-2948 is an isolated, 44 \rm{ms} pulsar that has been partially recycled and is likely a former member of a binary system which was disrupted by a second supernova. The paucity of such so-called `disrupted binary pulsars' (DRPs) compared to double neutron star (DNS) binaries can be used to test current evolutionary scenarios, especially the kicks imparted on the neutron stars in the second supernova. There is some evidence that DRPs have larger space velocities, which could explain their small numbers. PSR J1806+2819 is a 15 \rm{ms} pulsar in a 44 day orbit with a low mass white dwarf companion. We did not detect the companion in archival optical data, indicating that it must be older than 1200 Myr.Comment: 9 pages, 5 figure

    The Green Bank North Celestial Cap Pulsar Survey. IV: Four New Timing Solutions

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    We present timing solutions for four pulsars discovered in the Green Bank Northern Celestial Cap (GBNCC) survey. All four pulsars are isolated with spin periods between 0.26ā€‰\,s and 1.84ā€‰\,s. PSR J0038āˆ’-2501 has a 0.26ā€‰\,s period and a period derivative of 7.6Ɨ10āˆ’19ā€‰sā€‰sāˆ’1{7.6} \times {10}^{-19}\,{\rm s\,s}^{-1}, which is unusually low for isolated pulsars with similar periods. This low period derivative may be simply an extreme value for an isolated pulsar or it could indicate an unusual evolution path for PSR J0038āˆ’-2501, such as a disrupted recycled pulsar (DRP) from a binary system or an orphaned central compact object (CCO). Correcting the observed spin-down rate for the Shklovskii effect suggests that this pulsar may have an unusually low space velocity, which is consistent with expectations for DRPs. There is no X-ray emission detected from PSR J0038āˆ’-2501 in an archival swift observation, which suggests that it is not a young orphaned CCO. The high dispersion measure of PSR J1949+3426 suggests a distance of 12.3ā€‰\,kpc. This distance indicates that PSR J1949+3426 is among the most distant 7% of Galactic field pulsars, and is one of the most luminous pulsars.Comment: 7 pages, 5 figure

    Imagining new feminist futures:How feminist social movements contest the neoliberalization of feminism in an increasingly corporateā€dominated world

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    Increasingly it is argued that feminism has been coā€opted by neoliberal agendas: becoming more individualistic and losing touch with its wider social change objectives. The neoliberalization of feminism is driven in part by increased corporate power, including the growing role of corporations in governance arenas, and corporate social responsibility agendas. However, we turn to social movement theory to elucidate strategies that social movements, including feminist social movements, are adopting in such spaces. In so doing, we find that feminist activists are engaging with new political opportunities, mobilizing structures and strategic framing processes that emerge in the context of increasingly neoliberal and privatized governance systems. We suggest that despite the significant challenges to their agendas, far from being coā€opted by neoliberalism, feminist social movements remain robust, existing alongside and developing new strategies to contest the neoliberalization of feminism in a variety of innovative ways

    Do Queens of Bumblebee Species Differ In Their Choice Of Flower Colour Morphs Of Corydalis Cava (Fumariaceae)?

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    International audienceAbstractBumblebee queens require a continuous supply of flowering food plants from early spring for the successful development of annual colonies. Early in spring, Corydalis cava provides essential nectar and pollen resources and a choice of flower colour. In this paper, we examine flower colour choice (purple or white) in C. cava and verify the hypothesis that bumblebee queens differ in their choice of flower colour. A total of 10,615 observations of flower visits were made in spring 2011 and spring 2014 near Poznań, western Poland. Our results suggest that Bombus lucorum/cryptarum used purple flowers less, while Bombus terrestris used purple flowers more and Bombus hortorum showed no preference. Therefore, the colour morphs of C. cava are probably co-evolutionary adaptations to the development of another part of the insect community which has different colour preferences
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