1,500 research outputs found

    A nebula around Nova BT Monocerotis

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    We report the spectroscopic discovery of nebular Hα emission around Nova BT Monocerotis. The indicated expansion distance to this system is about 1800 pc

    Fertility Parameters in Crossbred Sows Treated with Cloprostenol Sodium (Synchromate®) in Zaria, Nigeria

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    This study was carried out to evaluate fertility parameters in crossbred sows in Zaria, following treatment with Cloprostenol sodium (Synchromate®). Ten (n = 10) apparently healthy crossbred sows were randomly assigned to two equal treatment groups based on number of injections of 500μg Synchromate®. Group 1 received two injections on days 0 and 13, while Group 2 received three injections on days 0, 7 and 13. Oestrus was monitored visually for signs of oestrus twice daily from 0700 – 1000h and 1500 – 1800h. The fertility parameters evaluated were: oestrus response rate (ORR), time to onset of oestrus (TOO), duration of oestrus (DOO), conception rate (CR), pregnancy rate (PR), farrowing rate (FR) and litter size (LS). Data on ORR, CR, PR and FR were expressed in percentages while TOO, DOO and LS were expressed as mean ± SEM. Student t-test and Tukey’s post-hoc test were used to compare the percentages and mean values between the groups. The Graphpad Prism® data package was used for statistical analysis and values of P<0.05 were considered significant. Fertility parameters TOO, DOO, LS, ORR, CR, PR, FR for Group 1 (187.20 ± 8.98h, 87.60 ± 4.49h, 7.25 ± 1.44, 100 %, 60 %, 80 % and 100 % respectively) and Group 2 (176.00 ± 40.00h, 86.60 ± 13.36h, 7.50 ± 1.50, 60 %, 100 %, 80 % and 66.67 % respectively). The differences in fertility parameters between the groups were not statistically significant. It is recommended therefore that double injections of cloprostenol sodium (Synchromate®) should be used for oestrus synchronization as it increases fertility parameters in cross bred sows at 13 days apart.Key words: Fertility parameters, crossbred sows, cloprostenol sodium, Zaria

    Sea-surface temperature anomalies mediate changes in fish richness and abundance in Atlantic and Gulf of Mexico estuaries

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    Aim Anthropogenic warming of marine systems has caused biological and physiological responses that are fundamentally altering ecosystem structure. Because estuaries exist at the land-ocean interface, they are particularly vulnerable to the effects of ocean warming as they can undergo rapid biogeochemical and hydrological shifts due to climate and land-use change. We explored how multiple components of estuarine fish diversity—turnover, richness, and abundance—have changed in the North Atlantic and Gulf of Mexico estuaries across space and time and the drivers of change. Location North Atlantic and Gulf of Mexico. Taxa Fish. Method We compiled long-term (>30 years), continent-wide fisheries independent trawl surveys conducted in estuaries—from the Gulf of Maine to the Gulf of Mexico (U.S. waters)—and combined these with climate and land-use-land-cover data to examine trends and ecological drivers of fish richness, abundance and turnover using mixed-effect models. Results Species richness, abundance and turnover have increased in North Atlantic and Gulf of Mexico estuaries in the last 30 years. These changes were mediated largely by sea-surface temperature anomalies, especially in more northern estuaries where warming has been relatively pronounced. Main Conclusion The increasing trajectory of turnover in many estuaries suggests that fish communities have changed fundamentally from the baselines. A fundamental change in community composition can lead to an irreversible trophic imbalance or alternative stable states among other outcomes. Thus, predicting how shifting community structures might influence food webs, ecosystem stability, and human resource use remain a pertinent task

    Smoking cessation and survival in lung, upper aero-digestive tract and bladder cancer: cohort study

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    Background: The aim was to examine the association between smoking cessation and prognosis in smoking-related cancer as it is unclear that cessation reduces mortality. Methods: In this retrospective cohort study from 1999 to 2013, we assessed the association between cessation during the first year after diagnosis and all-cause and cancer- specific mortality. Results: Of 2,882 lung, 757 upper aero-digestive tract and 1,733 bladder cancer patients 27%, 29% and 21% of lung, UAT and bladder cancer patients quit smoking. In lung cancer patients that quit, all-cause mortality was significantly lower (HR 0.82 (0.74-0.92), while cancer-specific mortality (HR 0.89 (0.76-1.04) and death due to index cancer (HR 0.90 (0.77-1.05) were nonsignificantly lower. In UAT cancer, all-cause mortality (HR 0.81 (0.58-1.14), cancer-specific mortality (HR 0.84 (0.48-1.45), and death due to index cancer (HR 0.75 (0.42-1.34) were non-significantly lower. There was no evidence of an association between quitting and mortality in bladder cancer. The HRs were 1.02 (0.81 1.30) for all-cause, 1.23 (0.81-1.86) for cancer specific, and 1.25 (0.71-2.20) for death due to index cancer. These showed a nonsignificantly lower risk in sensitivity analyses. Conclusion: People with lung and possibly UAT cancer who quit smoking have a lower risk of mortality than people who continue smoking

    TOPAZ4: an ocean-sea ice data assimilation system for the North Atlantic and Arctic

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    We present a detailed description of TOPAZ4, the latest version of TOPAZ – a coupled ocean-sea ice data assimilation system for the North Atlantic Ocean and Arctic. It is the only operational, large-scale ocean data assimilation system that uses the ensemble Kalman filter. This means that TOPAZ features a time-evolving, state-dependent estimate of the state error covariance. Based on results from the pilot MyOcean reanalysis for 2003–2008, we demonstrate that TOPAZ4 produces a realistic estimate of the ocean circulation in the North Atlantic and the sea-ice variability in the Arctic. We find that the ensemble spread for temperature and sea-level remains fairly constant throughout the reanalysis demonstrating that the data assimilation system is robust to ensemble collapse. Moreover, the ensemble spread for ice concentration is well correlated with the actual errors. This indicates that the ensemble statistics provide reliable state-dependent error estimates – a feature that is unique to ensemble-based data assimilation systems. We demonstrate that the quality of the reanalysis changes when different sea surface temperature products are assimilated, or when in-situ profiles below the ice in the Arctic Ocean are assimilated. We find that data assimilation improves the match to independent observations compared to a free model. Improvements are particularly noticeable for ice thickness, salinity in the Arctic, and temperature in the Fram Strait, but not for transport estimates or underwater temperature. At the same time, the pilot reanalysis has revealed several flaws in the system that have degraded its performance. Finally, we show that a simple bias estimation scheme can effectively detect the seasonal or constant bias in temperature and sea-level

    Densification behavior of spark plasma sintered duplex stainless steel reinforced with TiN nanoparticles

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    Abstract: Duplex stainless steel (SAF 2205) reinforced with titanium nitride (TiN) nanoparticles ranging from 0 to 8 wt% were fabricated in vacuum via spark plasma sintering (SPS) using optimized SPS process parameter of 1150 oC, 10 min and 100 oC/min. The influence of TiN addition on the densification and shrinkage mechanism of the fabricated duplex stainless steel composite were evaluated. The results indicate even dispersion of the TiN nanoparticles in the steel matrix during tubular mixing. The displacement and shrinkage rates showed three densification stages relating to micro-nano particles rearrangement, plastic deformation of the particles and rapid densification of the composite. The steel composite samples displayed relatively high densities in the range of 96-99 % of the calculated theoretical density but were noted to decrease with TiN content

    The Discovery and Broad-band Follow-up of the Transient Afterglow of GRB 980703

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    We report on the discovery of the radio, infrared and optical transient coincident with an X-ray transient proposed to be the afterglow of GRB 980703. At later times when the transient has faded below detection, we see an underlying galaxy with R=22.6; this galaxy is the brightest host galaxy (by nearly 2 magnitudes) of any cosmological GRB thus far. In keeping with an established trend, the GRB is not significantly offset from the host galaxy. Interpreting the multi-wavelength data in the framework of the popular fireball model requires that the synchrotron cooling break was between the optical and X-ray bands on July 8.5 UT and that the intrinsic extinction of the transient is Av=0.9. This is somewhat higher than the extinction for the galaxy as a whole, as estimated from spectroscopy.Comment: 5 pages, 3 figures, and 2 tables. Submitted to the Astrophysical Journal Letters on 27 August 199

    Quasi-simultaneous observations of the BL Lac object MK 501 in X-ray, UV, visible, IR and radio frequencies

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    Quasi-simultaneous observations of the BL Lacertae (Lac) objects MK 501 were performed for the first time at X-ray, ultraviolet, visible, infrared, and radio frequencies. The observed spectral slope from the X-ray to UV regions is positive and continuous, but that from the mid UV to visible light region becomes gradually flat and possibly turns down toward lower frequencies; the optical radio emission can not be accounted for by a single power law. Several theoretical models were considered for the emission mechanism. A quantitative comparison was performed with the synchrotron-self-Compton model; the total spectrum is found consistent with this model. The spectrum from visible light to X-ray is consistent with synchrotron radiation or with inverse-Compton scattering by a hot thermal cloud of electrons. The continuity of the spectral slope from X-ray to UV implied by the current data suggests that the previous estimates of the total luminosity of this BL Lac object is underestimated by a factor of about three or four
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