1,781 research outputs found

    Strike Hazard Posed By Columbids To Military Aircraft

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    Wildlife-aircraft strikes threaten both human and animal safety and result in hundreds of millions of dollars per year in aircraft damage and lost flight hours. Large-bodied birds are especially hazardous to aircraft. However, given high-speed flight at low altitudes, military aircraft may be especially vulnerable to strikes and more susceptible to damage even when encountering small birds. We summarized all wildlife-aircraft strike records from Randolph Air Force Base (San Antonio, Texas) over a 25-year period and compared the number and cost of strikes across avian species and species groups. Because columbids (i.e., pigeons and doves) are among the most frequently struck species by both civilian and military aircraft and because several columbid species have demonstrated marked population increases over the past decade, we also quantified characteristics (i.e., month, time of day, precipitation patterns, phase of flight, altitude) of columbid strikes. White-winged doves (Zenaida asiatica) have undergone a substantial northward range expansion over the past 60 years and are now numerous in San Antonio. Given local interest, we also highlighted characteristics of aircraft strikes involving this species. Though columbids were not the most frequently struck species group during the survey period (1990–2014), they were the most costly. Columbid strikes were more frequent from May to July than during other months and often occurred during morning hours, especially from 08:00–10:00, with a smaller afternoon peak from 15:00–17:00. Columbid strikes occurred during landing more than during other phases of flight, typically at ≤152 m above ground level (AGL), though white-winged doves were more likely to be struck on takeoff than expected. To reduce costs and safety concerns where columbids are prevalent, military flight planners, aircrews, and wildlife managers can reduce air travel, increase vigilance during takeoffs and landings, and implement on-the-ground hazing techniques in morning and late afternoon hours during spring and summer months

    Care coordination among pediatricians and dentists: a cross-sectional study of opinions of North Carolina dentists

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    Abstract: Background: Care coordination between physicians and dentists remains a challenge. This study of dentists providing pediatric dental care examined their opinions about physicians’ role in oral health and identified factors associated with these opinions. Methods: North Carolina general and pediatric dentists were surveyed on their opinions of how physicians should proceed after caries risk assessment and evaluation of an 18-month-old, low risk child. We estimated two multinomial logistic regression models to examine dentists’ responses to the scenario under the circumstances of an adequate and a limited dental workforce. Results: Among 376 dentists, 52% of dentists indicated physicians should immediately refer this child to a dental home with an adequate dental workforce. With a limited workforce, 34% recommended immediate referral. Regression analysis indicated that with an adequate workforce guideline awareness was associated with a significantly lower relative risk of dentists’ recommending the child remain in the medical home than immediate referral. Conclusions: Dentists’ opinions and professional guidelines on how physicians should promote early childhood oral health differ and warrant strategies to address such inconsistencies. Without consistent guidelines and their application, there is a missed opportunity to influence provider opinions to improve access to dental care

    Photometric Variability in the CSTAR Field: Results From the 2008 Data Set

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    The Chinese Small Telescope ARray (CSTAR) is the first telescope facility built at Dome A, Antarctica. During the 2008 observing season, the installation provided long-baseline and high-cadence photometric observations in the i-band for 18,145 targets within 20 deg2 CSTAR field around the South Celestial Pole for the purpose of monitoring the astronomical observing quality of Dome A and detecting various types of photometric variability. Using sensitive and robust detection methods, we discover 274 potential variables from this data set, 83 of which are new discoveries. We characterize most of them, providing the periods, amplitudes and classes of variability. The catalog of all these variables is presented along with the discussion of their statistical properties.Comment: 38 pages, 11 figures, 4 tables; Accepted for publication in ApJ

    Photometry of Variable Stars from Dome A, Antarctica

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    Dome A on the Antarctic plateau is likely one of the best observing sites on Earth thanks to the excellent atmospheric conditions present at the site during the long polar winter night. We present high-cadence time-series aperture photometry of 10,000 stars with i<14.5 mag located in a 23 square-degree region centered on the south celestial pole. The photometry was obtained with one of the CSTAR telescopes during 128 days of the 2008 Antarctic winter. We used this photometric data set to derive site statistics for Dome A and to search for variable stars. Thanks to the nearly-uninterrupted synoptic coverage, we find 6 times as many variables as previous surveys with similar magnitude limits. We detected 157 variable stars, of which 55% are unclassified, 27% are likely binaries and 17% are likely pulsating stars. The latter category includes delta Scuti, gamma Doradus and RR Lyrae variables. One variable may be a transiting exoplanet.Comment: Accepted for publication in the Astronomical Journal. PDF version with high-resolution figures available at http://faculty.physics.tamu.edu/lmacri/papers/wang11.pd

    Eclipsing Binaries From the CSTAR Project at Dome A, Antarctica

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    The Chinese Small Telescope ARray (CSTAR) has observed an area around the Celestial South Pole at Dome A since 2008. About 20,00020,000 light curves in the i band were obtained lasting from March to July, 2008. The photometric precision achieves about 4 mmag at i = 7.5 and 20 mmag at i = 12 within a 30 s exposure time. These light curves are analyzed using Lomb--Scargle, Phase Dispersion Minimization, and Box Least Squares methods to search for periodic signals. False positives may appear as a variable signature caused by contaminating stars and the observation mode of CSTAR. Therefore the period and position of each variable candidate are checked to eliminate false positives. Eclipsing binaries are removed by visual inspection, frequency spectrum analysis and locally linear embedding technique. We identify 53 eclipsing binaries in the field of view of CSTAR, containing 24 detached binaries, 8 semi-detached binaries, 18 contact binaries, and 3 ellipsoidal variables. To derive the parameters of these binaries, we use the Eclipsing Binaries via Artificial Intelligence (EBAI) method. The primary and the secondary eclipse timing variations (ETVs) for semi-detached and contact systems are analyzed. Correlated primary and secondary ETVs confirmed by false alarm tests may indicate an unseen perturbing companion. Through ETV analysis, we identify two triple systems (CSTAR J084612.64-883342.9 and CSTAR J220502.55-895206.7). The orbital parameters of the third body in CSTAR J220502.55-895206.7 are derived using a simple dynamical model.Comment: 41 pages, 12 figures; published online in ApJ

    Barriers to Pediatricians’ Adherence to American Academy of Pediatrics Oral Health Referral Guidelines: North Carolina General Dentists’ Opinions

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    Purpose—The purposes of this study were to: (1) assess knowledge, attitudes, and behaviors of North Carolina general dentists (GDs) regarding American Academy of Pediatrics (AAP) dental referral guidelines; and (2) determine factors that influence pediatricians’ ability to comply with AAP guidelines. Methods—One thousand GDs were surveyed to determine barriers toward acceptance of physician referrals of infants and toddlers. The primary outcome using ordered logistic regression was GDs’ acceptance of children described in five case scenarios, with different levels of risk and oral health status. Results—GDs believed pediatricians should refer patients at risk for caries to a dentist. While 61 to 75 percent of GDs were willing to accept low caries risk referrals of infants and toddlers, only 35 percent would accept referrals when caries was present. Predictors of referral acceptance were correct knowledge about AAP guidelines (OR=2.0, 95%CI=1.2-3.3), confidence in pro- viding preventive care to infants and toddlers (OR=2.6, 95%CI=1.3-4.9), and agreement that parents see importance in dental referrals (OR=2.1, 95% CI=1.2-3.6). Conclusions—This study identified factors influencing acceptance of pediatrician referrals for the age one dental visit among North Carolina GDs and highlighted challenges pediatricians face in referring young children for dental care

    PHOTOMETRY OF VARIABLE STARS FROM DOME A, ANTARCTICA: RESULTS FROM THE 2010 OBSERVING SEASON

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    We present results from a season of observations with the Chinese Small Telescope ARray (CSTAR), obtained over 183 days of the 2010 Antarctic winter. We carried out high-cadence time-series aperture photometry of 20,000 stars with i<15.3 mag located in a 23 square-degree region centered on the south celestial pole. We identified 188 variable stars, including 67 new objects relative to our 2008 observations, thanks to broader synoptic coverage, a deeper magnitude limit and a larger field of view. We used the photometric data set to derive site statistics from Dome A. Based on two years of observations, we find that extinction due to clouds at this site is less than 0.1 and 0.4 mag during 45% and 75% of the dark time, respectively.Comment: Accepted for publication in the Astronomical Journal. Light curves and finding charts of all variable stars will be made available at http://casdc.china-vo.org/data/csta

    The effects of administering different metaphylactic antimicrobials on growth performance and health outcomes of high-risk, newly received feedlot steers

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    Bovine respiratory disease (BRD) is the primary animal health concern facing feedlot producers. Many antimicrobial mitigation strategies are available, but few studies have compared feedlot performance during both the receiving and finishing periods following application of different antimicrobials used as metaphylaxis at arrival. The objective of this study was to compare antimicrobial metaphylaxis methods on clinical health and growth performance across both the receiving and finishing periods. A total of 238 multiple-sourced steers in two source blocks were used in a generalized complete block design. The four treatments included: 1) a negative control, 5 mL of sterile saline injected subcutaneously (CON); 2) subcutaneous administration of florfenicol at 40 mg/kg of BW (NUF); 3) subcutaneous administration of ceftiofur in the posterior aspect of the ear at 6.6 mg/kg of BW (EXC); and 4) subcutaneous administration of tulathromycin at 2.5 mg/kg of BW (DRA). The morbidity rate for the first treatment of BRD was decreased for the DRA and EXC treatments compared to CON and NUF (P \u3c 0.01). Additionally, average daily gain (ADG), dry matter intake (DMI), and gain-to-feed (G:F) were greater (P ≤ 0.02) in the DRA treatment during the receiving period compared to all other treatments. The ADG was also greater (P \u3c 0.05) for EXC than the CON treatment throughout the finishing period. Nonetheless, other growth performance variables did not differ among metaphylactic treatments during the finishing period (P ≥ 0.14). Likewise, no differences in carcass characteristics or liver abscess score were observed (P ≥ 0.18). All complete blood count (CBC) variables were affected by day (P ≤ 0.01) except mean corpuscular hemoglobin concentration (P = 0.29). Treatment × time interactions were observed for platelet count, white blood cell (WBC) count, monocyte count and percentage, and lymphocyte percentage (P ≤ 0.03). However, there were no observed hematological variables that differed among treatment (P ≥ 0.10). The results indicate that some commercially available antimicrobials labeled for metaphylactic use are more efficacious than others in decreasing morbidity rate

    Metaphylactic antimicrobial effects on occurrences of antimicrobial resistance in \u3ci\u3eSalmonella enterica, Escherichia coli\u3c/i\u3e and \u3ci\u3eEnterococcus\u3c/i\u3e spp. measured longitudinally from feedlot arrival to harvest in high-risk beef cattle

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    Aims: Our objective was to determine how injectable antimicrobials affected populations of Salmonella enterica, Escherichia coli and Enterococcus spp. in feedlot cattle. Methods and Results: Two arrival date blocks of high-risk crossbred beef cattle (n = 249; mean BW = 244 kg) were randomly assigned one of four antimicrobial treatments administered on day 0: sterile saline control (CON), tulathromycin (TUL), ceftiofur (CEF) or florfenicol (FLR). Faecal samples were collected on days 0, 28, 56, 112, 182 and study end (day 252 for block 1 and day 242 for block 2). Hide swabs and subiliac lymph nodes were collected the day before and the day of harvest. Samples were cultured for antimicrobial-resistant Salmonella, Escherichia coli and Enterococcus spp. The effect of treatment varied by day across all targeted bacterial populations (p ≤ 0.01) except total E. coli. Total E. coli counts were greatest on days 112, 182 and study end (p ≤ 0.01). Tulathromycin resulted in greater counts and prevalence of Salmonella from faeces than CON at study end (p ≤ 0.01). Tulathromycin and CEF yielded greater Salmonella hide prevalence and greater counts of 128ERYR E. coli at study end than CON (p ≤ 0.01). No faecal Salmonella resistant to tetracyclines or third-generation cephalosporins were detected. Ceftiofur was associated with greater counts of 8ERYR Enterococcus spp. at study end (p ≤ 0.03). By the day before harvest, antimicrobial use did not increase prevalence or counts for all other bacterial populations compared with CON (p ≥ 0.13). Conclusions: Antimicrobial resistance (AMR) in feedlot cattle is not caused solely by using a metaphylactic antimicrobial on arrival, but more likely a multitude of environmental and management factors
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