432 research outputs found

    Where are the beachmasters? Unexpectedly weak polygyny among southern elephant seals on a South Shetland Island

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    Intraspecific variation in animal mating systems can have important implications for ecological, evolutionary and demographic processes in wild populations. For example, patterns of mating can impact social structure, dispersal, effective population size and inbreeding. However, few species have been studied in sufficient detail to elucidate mating system plasticity and its dependence on ecological and demographic factors. Southern elephant seals (Mirounga leonina) have long been regarded as a textbook example of a polygynous mating system, with dominant ‘beachmaster’ males controlling harems of up to several hundred females. However, behavioural and genetic studies have uncovered appreciable geographic variation in the strength of polygyny among elephant seal populations. We, therefore, used molecular parentage analysis to investigate patterns of parentage in a small satellite colony of elephant seals at the South Shetland Islands. We hypothesised that dominant males would be able to successfully monopolise the relatively small numbers of females present in the colony, leading to relatively high levels of polygyny. A total of 424 individuals (comprising 33 adult males, 101 adult females and 290 pups) sampled over 8 years were genotyped at 20 microsatellites and reproductive success was analysed by genetically assigning parents. Paternity could only be assigned to 31 pups (10.7%), despite our panel of genetic markers being highly informative and the genotyping error rate being very low. The strength of inferred polygyny was weak in comparison to previous genetic studies of the same species, with the most successful male fathering only seven pups over the entire course of our study. Our results show that, even in a species long regarded as a model for extreme polygyny, male reproductive skew can vary substantially among populations

    An exploratory study on the effectiveness of virtual reality analgesia for children and adolescents with kidney diseases undergoing venipuncture

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    The current study evaluated the effectiveness of VR analgesia among pediatric and adolescent patients with kidney disease undergoing venipuncture. Patients at an Italian Children’s hospital (N = 82, age range 7–17 years) undergoing venipuncture were randomly assigned to a No VR group (non-medical conversation) vs. a Yes VR group (VR analgesia). After the procedure, patients gave 0–10 Verbal Numeric Pain Scale ratings. Compared with patients in the No VR Group, patients in the Yes VR group reported significantly lower “Pain intensity”(No VR mean = 2.74, SD = 2.76 vs. Yes VR mean = 1.56, SD = 1.83) and the VR group also rated “Pain unpleasantness” significantly lower than the No VR group (No VR mean = 2.41, SD = 0.94 vs. Yes VR mean = 1.17, SD = 1.80). Patients distracted with VR also reported having significantly more fun during the venipuncture procedure. No side effects emerged. In addition to reducing pain intensity, VR has the potential to make venipuncture a more fun and less unpleasant experience for children with CKD, as measured in the present study for the first time. Finally, in exploratory analyses, children aged 7–11 in the VR group reported 55% lower worst pain than control subjects in the same age range, whereas children aged 12 to 17 in the VR group only reported 35% lower worst pain than control subjects. Additional research and development using more immersive VR is recommended.info:eu-repo/semantics/publishedVersio

    Fiddling while the ice melts? How organizational scholars can take a more active role in the climate change debate

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    The debate over anthropogenic climate change or the idea that human activities are altering the physical climate of the planet continues to rage amid seemingly irreconcilable differences, both within the developed world and between developed and less developed countries. With high uncertainty, rival worldviews, and wide diversity of meaning attached to the expression, climate change has become a key narrative within which local and transnational issues – economic, social, and political – are framed and contested. The field is fraught with controversies regarding causes and consequences, as well as different attitudes toward risks, technologies, and economic and social well-being for different groups. Parties also dispute how to share responsibility for reducing emissions – whether the issue primarily needs market, regulatory, technological, or behavioral solutions. Climate change is many things to many people. Competing interests negotiate over its interpretation and utilize various strategies to promote practices that advance their own understandings regarding climate change and its governance

    Using immersive virtual reality distraction to reduce fear and anxiety before surgery

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    Presurgical anxiety is very common and is often treated with sedatives. Minimizing or avoiding sedation reduces the risk of sedation-related adverse events. Reducing sedation can increase early cognitive recovery and reduce time to discharge after surgery. The current case study is the first to explore the use of interactive eye-tracked VR as a nonpharmacologic anxiolytic customized for physically immobilized presurgery patients. Method: A 44-year-old female patient presenting for gallbladder surgery participated. Using a within-subject repeated measures design (treatment order randomized), the participant received no VR during one portion of her preoperative wait and interactive eye-tracked virtual reality during an equivalent portion of time in the presurgery room. After each condition (no VR vs. VR), the participant provided subjective 0–10 ratings and state–trait short form Y anxiety measures of the amount of anxiety and fear she experienced during that condition. Results: As predicted, compared to treatment as usual (no VR), the patient reported having 67% lower presurgical anxiety during VR. She also experienced “strong fear” (8 out of 10) during no VR vs. “no fear” (0 out of 10) during VR. She reported a strong sense of presence during VR and zero nausea. She liked VR, she had fun during VR, and she recommended VR to future patients during pre-op. Interactive VR distraction with eye tracking was an effective nonpharmacologic technique for reducing anticipatory fear and anxiety prior to surgery. The results add to existing evidence that supports the use of VR in perioperative settings. VR technology has recently become affordable and more user friendly, increasing the potential for widespread dissemination into medical practice. Although case studies are scientifically inconclusive by nature, they help identify new directions for future larger, carefully controlled studies. VR sedation is a promising non-drug fear and anxiety management technique meriting further investigation.info:eu-repo/semantics/publishedVersio

    Virtual Reality Analgesia for Pediatric Dental Patients

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    Background: Dental procedures often elicit pain and fear in pediatric dental patients.Aim: To evaluate the feasibility and effectiveness of immersive virtual reality as an attention distraction analgesia technique for pain management in children and adolescents undergoing painful dental procedures.Design: Using a within-subjects design, five patients (mean age 13.20 years old, SD 2.39) participated. Patients received tethered immersive interactive virtual reality distraction in an Oculus Rift VR helmet (experimental condition) during one dental procedure (a single dental filling or tooth extraction). On a different visit to the same dentist (e.g., 1 week later), each patient also received a comparable dental procedure during the control condition “treatment as usual” (treatment order randomized). After each procedure, children self-rated their “worst pain,” “pain unpleasantness,” “time spent thinking about pain,” “presence in VR,” “fun,” and “nausea” levels during the dental procedures, using graphic rating scales.Results: Patients reported significantly lower “worst pain” and “pain unpleasantness,” and had significantly more fun during VR, compared to a comparable dental procedure with No VR. Using Oculus Rift VR goggles, patients reported a “strong sense of going inside the computer-generated world,” without side effects. The dentist preferred having the patients in VR.Conclusion: Results of this pilot study provide preliminary evidence of the feasibility of using immersive, interactive VR to distract pediatric dental patients and increase fun of children during dental procedures

    The Effect of Multiple Scattering on the Polarization from Binary Star Envelopes. I. Self- and Externally Illuminated Disks

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    We present the results of a Monte Carlo radiative transfer code that calculates the polarization produced by multiple Thomson scattering and variable absorptive opacity in a circumstellar disk around one component of a close detached binary system. We consider in detail the polarization variations over the binary cycle that result from the disk's illumination by the external star and by its own volume emission. We identify key features of these polarization phase curves and investigate their behavior as functions of optical depth, albedo, and inclination for geometrically thin and thick disks. The polarization due to disk self-illumination is sensitive to the internal optical characteristics of the disk, while the polarization arising from external illumination is mainly sensitive to the disk's geometrical thickness. With appropriate flux weighting, these results, combined with those for an internally illuminated disk, allow simulation of the polarization signature from an arbitrary binary-disk system.Comment: 34 pages, 17 figures. Submitted to ApJ, revised in response to referee comments. Color figures available from http://www.ruf.rice.edu/~jhoffman/monte/colorfigs.htm

    Virtual Reality Analgesia During Venipuncture in Pediatric Patients With Onco-Hematological Diseases

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    Background: Venipuncture is described by children as one of the most painful and frightening medical procedures.Objective: To evaluate the effectiveness of Virtual Reality (VR) as a distraction technique to help control pain in children and adolescents undergoing venipuncture.Methods: Using a within-subjects design, fifteen patients (mean age 10.92, SD = 2.64) suffering from oncological or hematological diseases received one venipuncture with “No VR” and one venipuncture with “Yes VR” on two separate days (treatment order randomized). “Time spent thinking about pain”, “Pain Unpleasantness”, “Worst pain” the quality of VR experience, fun during the venipuncture and nausea were measured.Results: During VR, patients reported significant reductions in “Time spent thinking about pain,” “Pain unpleasantness,” and “Worst pain”. Patients also reported significantly more fun during VR, and reported a “Strong sense of going inside the computer-generated world” during VR. No side effects were reported.Conclusion: VR can be considered an effective distraction technique for children and adolescents’ pain management during venipuncture. Moreover, VR may elicit positive emotions, more than traditional distraction techniques. This could help patients cope with venipuncture in a non-stressful manner. Additional research and development is needed

    The Arecibo Legacy Fast ALFA Survey: II. Results of Precursor Observations

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    In preparation for the full Arecibo Legacy Fast ALFA extragalactic HI survey, precursor observations were carried out in Aug--Sep 2004 with the 7-beam Arecibo L-band feed array (ALFA) receiver system and the WAPP spectral processors. While these observations were geared mainly at testing and debugging survey strategy, hardware and software, approximately 36 hours of telescope time yielded science--quality data. From those observations, an initial list of 730 tentative detections of varying degree of reliability was extracted. Ninety--eight high signal-to-noise candidates were deemed to be bona fide HI line detections. To test our ability to discriminate cosmic signals from RFI and noise, 165 candidates ranging in reliability likelihood were re--observed with the single beam L--band wide system at Arecibo in Jan--Feb 2005. Of those, 41% were confirmed as real. We present the results of both the ALFA and single beam observations for the sample of 166 confirmed HI sources, as well as our assessment of their optical counterparts. Of the 166 sources, 62 coincide with previously known HI sources, while optical redshifts were available for an additional 18 galaxies; thus, 52% of the redshifts reported here were previously unknown. Of the 166 HI detections, 115 are identified with previously cataloged galaxies, of either known or unknown redshift, leaving 51 objects identified for the first time. Because of the higher sensitivity of the Arecibo system, fewer than 10% of the 166 HI sources would have been detected by a HIPASS--like survey of the same region. Three of the objects have HI masses less than 10^7 solar masses. The full ALFALFA survey which commenced in February 2005 should detect more than 100 times as many objects of similarly low HI mass over the next 5 years.Comment: 40 pages, including 4 tables and 8 figures; to appear in Astron. J.; see http://egg.astro.cornell.edu/alfalfa/pubs.ph

    The Arecibo Legacy Fast ALFA Survey: III. HI Source Catalog of the Northern Virgo Cluster Region

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    We present the first installment of HI sources extracted from the Arecibo Legacy Fast ALFA (ALFALFA) extragalactic survey, initiated in 2005. Sources have been extracted from 3-D spectral data cubes and then examined interactively to yield global HI parameters. A total of 730 HI detections are catalogued within the solid angle 11h44m < R.A.(J2000) < 14h00m and +12deg < Dec.(J2000) < +16deg, and redshift range -1600 \kms < cz < 18000 \kms. In comparison, the HI Parkes All-Sky Survey (HIPASS) detected 40 HI signals in the same region. Optical counterparts are assigned via examination of digital optical imaging databases. ALFALFA HI detections are reported for three distinct classes of signals: (a) detections, typically with S/N > 6.5; (b) high velocity clouds in the Milky Way or its periphery; and (c) signals of lower S/N (to ~ 4.5) which coincide spatially with an optical object of known similar redshift. Although this region of the sky has been heavily surveyed by previous targeted observations based on optical flux-- or size-- limited samples, 69% of the extracted sources are newly reported HI detections. The resultant positional accuracy of HI sources is 20" (median). The median redshift of the sample is ~7000 \kms and its distribution reflects the known local large scale structure including the Virgo cluster. Several extended HI features are found in the vicinity of the Virgo cluster. A small percentage (6%) of HI detections have no identifiable optical counterpart, more than half of which are high velocity clouds in the Milky Way vicinity; the remaining 17 objects do not appear connected to or associated with any known galaxy.Comment: Astronomical Journal, in pres
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