Here, we report the discovery of a kilonova associated with the nearby (350 Mpc) minute-duration GRB 211211A. In tandem with deep optical limits that rule out the presence of an accompanying ...supernova to \(M_I > -13\) mag at 17.7 days post-burst, the identification of a kilonova confirms that this burst's progenitor was a compact object merger. While the spectrally softer tail in GRB 211211A's gamma-ray light curve is reminiscent of previous extended emission short GRBs (EE-SGRBs), its prompt, bright spikes last \(\gtrsim 12\) s, separating it from past EE-SGRBs. GRB 211211A's kilonova has a similar luminosity, duration and color to AT2017gfo, the kilonova found in association with the gravitational wave (GW)-detected binary neutron star (BNS) merger GW170817. We find that the merger ejected \(\approx 0.04 M_{\odot}\) of r-process-rich material, and is consistent with the merger of two neutron stars (NSs) with masses close to the canonical \(1.4 M_{\odot}\). This discovery implies that GRBs with long, complex light curves can be spawned from compact object merger events and that a population of kilonovae following GRBs with durations \(\gg 2\) s should be accounted for in calculations of the NS merger r-process contribution and rate. At 350 Mpc, the current network of GW interferometers at design sensitivity would have detected the merger precipitating GRB 211211A, had it been operating at the time of the event. Further searches for GW signals coincident with long GRBs are therefore a promising route for future multi-messenger astronomy.
Bromodichloromethane (BDCM) is a common municipal drinking water disinfection by-product, resulting in widespread trace human exposure via ingestion and inhalation. The present studies were designed ...to define organ-specific, BDCM-induced toxicity in wild type (p53(+/+)) and heterozygous (p53(+/-)) mice on both the FVB/N and C57BL/6 genetic backgrounds. Mice were exposed to BDCM vapor daily for 6 h/day and 7 days/week at concentrations of 0, 1, 10, 30, 100, or 150 ppm for 1 week and at 0, 0.3, 1, 3, 10, or 30 ppm for 3 weeks. In the 1-week exposure study, dose-dependent mortality and morbidity were observed at concentrations of 30 ppm and above and were as high as 100% at 150 ppm. In the 3-week exposure study, mortality and morbidity were found only in the 30-ppm exposure groups and were 0, 17, 67, and 33% for the wild-type C57BL/6, p53(+/-) C57BL/6, wild-type FVB/N, and p53(+/-) FVB/N mice, respectively. BDCM was a particularly potent kidney cytotoxicant. Dose-dependent tubular degeneration, necrosis, and associated regenerative cell proliferation greater than 10-fold over controls were seen at concentrations as low as 10 ppm in the kidneys of all strains at 1 week. Similar dose-dependent increases in hepatic necrosis, degeneration, and regenerative cell proliferation were observed but were induced only at concentrations of 30 ppm and higher. Pathological changes were more severe in the FVB/N compared to the C57BL/6 mice and were more severe in the heterozygotes compared to the wild-type mice. However, recovery and return of the percentage of kidney cells in S-phase to control levels was seen at 3 weeks. The estimated maximum tolerated dose for longer-term exposures was 15 ppm, based on mortality, induced kidney pathology, and regenerative cell proliferation. A one-year cancer bioassay was initiated with doses of 0, 0.5, 3, 10, and 15 ppm, based on this information. No pathological changes in the livers were found at the 13-week time point of that study. At 13 weeks, the kidney lesions and regenerative cell proliferation seen at the 1-week time point at doses of 10 ppm and above had resolved, and the cell proliferation rates had returned to baseline. Differences in toxicity indicate that caution be used in substituting wild-type mice for transgenic mice for range-finding studies to select doses for p53(+/-) cancer studies. Resolution of the kidney lesions indicates that periods of very high regenerative cell proliferation, potentially important in the carcinogenic process, may not be observed if measurements are taken only at 3 weeks of exposure or later.
The discovery of GW170817 and GRB 170817A in tandem with AT 2017gfo cemented the connection between neutron star mergers, short gamma-ray bursts (GRBs), and kilonovae. To investigate short GRB ...observations in the context of diverse kilonova behavior, we present a comprehensive optical and near-infrared (NIR) catalog of 85 bursts discovered over 2005-2020 on timescales of \(\lesssim12\) days. The sample includes previously unpublished observations of 23 bursts, and encompasses both detections and deep upper limits. We identify 11.8% and 15.3% of short GRBs in our catalog with upper limits that probe luminosities lower than those of AT 2017gfo and a fiducial NSBH kilonovae model (for pole-on orientations), respectively. We quantify the ejecta masses allowed by the deepest limits in our catalog, constraining blue and `extremely blue' kilonova components of 14.1% of bursts to \(M_{\rm ej}\lesssim0.01-0.1 M_{\odot}\). The sample of short GRBs is not particularly constraining for red kilonova components. Motivated by the large catalog as well as model predictions of diverse kilonova behavior, we investigate modified search strategies for future follow-up to short GRBs. We find that ground-based optical and NIR observations on timescales of \(\gtrsim 2\) days can play a significant role in constraining more diverse outcomes. We expect future short GRB follow up efforts, such as from the {\it James Webb Space Telescope}, to expand the reach of kilonova detectability to redshifts of \(z\approx 1\).
Abstract Purpose We hypothesize that intensive care unit (ICU) families frequently perceive that they have received inconsistent information from staff about their relatives and that these ...inconsistencies influence abilities to make medical decisions, as well as satisfaction. Materials and Methods We performed a prospective cohort study in the neurosciences and medical ICU at a university hospital. One hundred twenty-four family members of adult patients surviving to ICU discharge completed a questionnaire regarding perceptions of inconsistent information. Results Of 193 eligible patients, 64.2% had family complete the survey. Thirty-one respondents (25.0%; 95% confidence interval, 7.7) reported at least 1 instance of inconsistent information during their family member's admission, with no difference between the neurosciences ICU (21.5%; 9.3) and the medical ICU (31.1%; 14.1; P = .28). Of those who did receive inconsistent information, 38.7% (95% confidence interval, 18.2) reported multiple episodes and 74.2% (16.3) indicated that episodes occurred within the first 48 hours of admission. These episodes had an adverse effect, with 19.4% (14.7) indicating that they affected satisfaction and 9.7% (11.0) indicating that they made decision making difficult. Conclusions Episodes involving inconsistent information from staff as perceived by families may be quite prevalent and may influence decision-making abilities and satisfaction.
Background: A review of the periodontal literature offers little information concerning trends in referral patterns of patients for periodontal therapy. Over the last 2 decades, there has been a ...significant increase in the knowledge base concerning inflammatory periodontal disease. It might be assumed that the collective advances in knowledge have impacted periodontal referral patterns. Thus, the purpose of this study was to examine the differences in periodontal referral patterns in the same offices separated by a 20‐year interval (i.e., 1980 and 2000).
Methods: A retrospective chart analysis was conducted on a total of 782 patient charts from three conveniently selected periodontal practices. Charts were randomly selected from two time periods: 1980‐ 1981 and 2000‐2001. The following information was obtained from each patient record: gender, age at time of initial examination, tobacco smoking status at time of initial examination, periodontal case type, number of missing teeth at initial examination (not including third molars), and number of teeth scheduled for extraction per periodontal treatment plan. Descriptive data were analyzed using frequency distributions, measures of central tendency, and measures of dispersion. Non‐parametric statistics were used to examine the relationship of disease severity as a function of site, time period, and patient age.
Results: The following trends were noted: 1) an increase in the average age of patients at the time of the initial examination; 2) a decrease in the percentage of patients using tobacco at the time of the initial interview; 3) an increase in the percentage of periodontal Case Type IV patients with a concomitant decrease in the number of periodontal Case Type III patients; 4) an increase in the average number of missing teeth per patient at the initial examination; and 5) an increase in the average number of teeth scheduled for extraction per periodontal treatment plan.
Conclusions: Characteristics of patients referred in 1980 compared to those referred in the year 2000 indicate that, although fewer patients used tobacco, there were several noteworthy trends. At referral, patients exhibited a greater loss of teeth, had more severe disease, and required extraction of a greater number of teeth in 2000 compared to 1980. Possible reasons for these trends are discussed. J Periodontol 2003;74:1470‐1474.
Aim To examine the uniqueness and relationship of islands in the San Diegan Province using reef fishes. Location Pacific coast of Baja and Southern California. Methods Quantitative scuba surveys and ...statistics were used. Between June 2000 and August 2002, the nearshore rocky-reef fishes of eight southern California and Baja California islands were quantitatively surveyed. The islands surveyed were: Santa Cruz, San Nicolas, Santa Barbara, Santa Catalina, San Clemente, North Coronado, San Martin and San Benito. These islands span the latitudinal range of offshore islands within the San Diegan marine province. This regional scale approach provided not only the first quantitative description of rocky-reef fishes at five of these islands, but also allowed comparisons with known biogeographical patterns. Results Here we discuss the distribution and abundance of 84 conspicuous rocky-reef fishes from 35 families. In general, the richness, diversity and composition of fish assemblages at these islands were found to reflect previously described biogeographical processes. The rocky reef fish assemblages of all islands in the survey were found to be significantly distinctive form each other. Phenetic analyses revealed two clusters. San Clemente, Santa Catalina and North Coronado clustered as a warm-water assemblage in the middle of the San Diegan Province. The remaining islands grouped together as a cold-water assemblage, despite the geographically disjunct position of the islands within this cluster. The relatedness of islands was independent of distance. Examination of the most common fish species at all islands revealed that while some conformed to the north-south trending density distributions predicted by previous investigators, the distribution of others could not be explained by latitude or temperature regimes. No single pattern explained the density of fishes at all islands. Both the rock croaker, Pareques sp., and flag cabrilla, Epinephelus labriformis, were observed at San Benito during these surveys, representing northern range extensions and may be indicators of the warming trend observed in this marine province. Main conclusion For nearshore rocky-reef fishes, the islands of the San Diegan marine province are distinct and their interrelatedness is independent of the distance between them.
This review of late-Holocene palaeoclimatology represents the results from a PAGES/CLIVAR Intersection Panel meeting that took place in June 2006. The review is in three parts: the principal ...high-resolution proxy disciplines (trees, corals, ice cores and documentary evidence), emphasizing current issues in their use for climate reconstruction; the various approaches that have been adopted to combine multiple climate proxy records to provide estimates of past annual-to-decadal timescale Northern Hemisphere surface temperatures and other climate variables, such as large-scale circulation indices; and the forcing histories used in climate model simulations of the past millennium. We discuss the need to develop a framework through which current and new approaches to interpreting these proxy data may be rigorously assessed using pseudo-proxies derived from climate model runs, where the `answer' is known. The article concludes with a list of recommendations. First, more raw proxy data are required from the diverse disciplines and from more locations, as well as replication, for all proxy sources, of the basic raw measurements to improve absolute dating, and to better distinguish the proxy climate signal from noise. Second, more effort is required to improve the understanding of what individual proxies respond to, supported by more site measurements and process studies. These activities should also be mindful of the correlation structure of instrumental data, indicating which adjacent proxy records ought to be in agreement and which not. Third, large-scale climate reconstructions should be attempted using a wide variety of techniques, emphasizing those for which quantified errors can be estimated at specified timescales. Fourth, a greater use of climate model simulations is needed to guide the choice of reconstruction techniques (the pseudo-proxy concept) and possibly help determine where, given limited resources, future sampling should be concentrated.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
In this work, BV RI light curves of 55 Type II supernovae (SNe II) from the Lick Observatory Supernova Search program obtained with the Katzman Automatic Imaging Telescope and the 1 m Nickel ...telescope from 2006 to 2018 are presented. Additionally, more than 150 spectra gathered with the 3 m Shane telescope are published. We conduct an analyse of the peak absolute magnitudes, decline rates, and time durations of different phases of the light and colour curves. Typically, our light curves are sampled with a median cadence of 5.5 days for a total of 5093 photometric points. In average V-band plateau declines with a rate of 1.29 mag (100 days)-1, which is consistent with previously published samples. For each band, the plateau slope correlates with the plateau length and the absolute peak magnitude: SNe II with steeper decline have shorter plateau duration and are brighter. A time-evolution analysis of spectral lines in term of velocities and pseudoequivalent widths is also presented in this paper. Our spectroscopic sample ranges between 1 and 200 days post-explosion and has a median ejecta expansion velocity at 50 days post-explosion of 6500 km/s (Halpha line) and a standard dispersion of 2000 km/s. Nebular spectra are in good agreement with theoretical models using a progenitor star having a mass <16 Msol. All the data are available to the community and will help to understand SN II diversity better, and therefore to improve their utility as cosmological distance indicators.
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