980 research outputs found

    "At have sit liv forbrudt". Henrettelser på Roskilde-egnen

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    "At have sit liv forbrudt". Henrettelser på Roskilde-egne

    Laudatores Temporis Acti, or Why Cosmology is Alive and Well - A Reply to Disney

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    A recent criticism of cosmological methodology and achievements by Disney (2000) is assessed. Some historical and epistemological fallacies in the said article have been highlighted. It is shown that---both empirically and epistemologically---modern cosmology lies on sounder foundations than it is portrayed. A brief historical account demonstrates that this form of unsatisfaction with cosmology has had a long tradition, and rather meagre results in the course of the XX century.Comment: 11 pages, no figures; a criticism of astro-ph/0009020; Gen. Rel. Grav., accepted for publicatio

    P.A.M. Dirac and the Discovery of Quantum Mechanics

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    Dirac's contributions to the discovery of non-relativistic quantum mechanics and quantum electrodynamics, prior to his discovery of the relativistic wave equation, are described

    Observable Quantities in Weyl Gravity

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    In this paper, the cosmological "constant" and the Hubble parameter are considered in the Weyl theory of gravity, by taking them as functions of rr and tt, respectively. Based on this theory and in the linear approximation, we obtain the values of H0H_0 and Λ0\Lambda_0 which are in good agreement with the known values of the parameters for the current state of the universe.Comment: to be appear in MPL

    Effects of PTSD and MDD Comorbidity on Psychological Changes during Surf Therapy Sessions for Active Duty Service Members

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    Together, posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) are debilitating and commonly comorbid; however, the effects of this comorbidity on psychological outcomes during exercise programs, such as surf therapy, have not been examined. This study compared changes in depression/anxiety and positive affect during surf therapy sessions between active duty service members with comorbid PTSD and MDD and those with either disorder alone. The study applied DSM-5 criteria to baseline self-report measures to assign probable disorder status, and used a longitudinal design involving repeated measurements to assess outcomes within 6 weekly sessions. Service members completed validated self-report questionnaires using the Patient Health Questionnaire-4 and the Positive Affect Schedule before and after each session. Within surf therapy sessions, both the comorbid and single disorder groups reported significant improvements in symptoms of depression/anxiety and positive affect. However, those with comorbid PTSD and MDD experienced significantly greater reductions in depression/anxiety (beta = -1.22, p = .028) and significantly greater improvements in positive affect (beta = 3.94, p = .046) compared with the single disorder group. Surf therapy appears to have global effects on psychological symptom reduction and may be a useful adjunctive intervention for the treatment of comorbid PTSD and MDD in both clinical and community health settings

    Effects of PTSD and MDD Comorbidity on Psychological Changes during Surf Therapy Sessions for Active Duty Service Members

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    Together, posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) are debilitating and commonly comorbid; however, the effects of this comorbidity on psychological outcomes during exercise programs, such as surf therapy, have not been examined. This study compared changes in depression/anxiety and positive affect during surf therapy sessions between active duty service members with comorbid PTSD and MDD and those with either disorder alone. The study applied DSM-5 criteria to baseline self-report measures to assign probable disorder status, and used a longitudinal design involving repeated measurements to assess outcomes within 6 weekly sessions. Service members completed validated self-report questionnaires using the Patient Health Questionnaire-4 and the Positive Affect Schedule before and after each session. Within surf therapy sessions, both the comorbid and single disorder groups reported significant improvements in symptoms of depression/anxiety and positive affect. However, those with comorbid PTSD and MDD experienced significantly greater reductions in depression/anxiety (beta = -1.22, p = .028) and significantly greater improvements in positive affect (beta = 3.94, p = .046) compared with the single disorder group. Surf therapy appears to have global effects on psychological symptom reduction and may be a useful adjunctive intervention for the treatment of comorbid PTSD and MDD in both clinical and community health settings

    A Testable Solution of the Cosmological Constant and Coincidence Problems

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    We present a new solution to the cosmological constant (CC) and coincidence problems in which the observed value of the CC, Λ\Lambda, is linked to other observable properties of the universe. This is achieved by promoting the CC from a parameter which must to specified, to a field which can take many possible values. The observed value of Lambda ~ 1/(9.3 Gyrs)^2(approximately10(−120)inPlanckunits)isdeterminedbyanewconstraintequationwhichfollowsfromtheapplicationofacausallyrestrictedvariationprinciple.Whenappliedtoourvisibleuniverse,themodelmakesatestablepredictionforthedimensionlessspatialcurvatureofOmegak0=−0.0056sb/0.5;wheresb 1/2isaQCDparameter.Requiringthataclassicalhistoryexist,ourmodeldeterminestheprobabilityofobservingagivenLambda.TheobservedCCvalue,whichwesuccessfullypredict,istypicalwithinourmodelevenbeforetheeffectsofanthropicselectionareincluded.Whenanthropicselectioneffectsareaccountedfor,wefindthattheobservedcoincidencebetweentLambda=Lambda(−1/2)andtheageoftheuniverse,tU,isatypicaloccurrenceinourmodel.IncontrasttomultiverseexplanationsoftheCCproblems,oursolutionisindependentofthechoiceofapriorweightingofdifferent (approximately 10^(-120) in Planck units) is determined by a new constraint equation which follows from the application of a causally restricted variation principle. When applied to our visible universe, the model makes a testable prediction for the dimensionless spatial curvature of Omega_k0 = -0.0056 s_b/0.5; where s_b ~ 1/2 is a QCD parameter. Requiring that a classical history exist, our model determines the probability of observing a given Lambda. The observed CC value, which we successfully predict, is typical within our model even before the effects of anthropic selection are included. When anthropic selection effects are accounted for, we find that the observed coincidence between t_Lambda = Lambda^(-1/2) and the age of the universe, t_U, is a typical occurrence in our model. In contrast to multiverse explanations of the CC problems, our solution is independent of the choice of a prior weighting of different \Lambda$-values and does not rely on anthropic selection effects. Our model includes no unnatural small parameters and does not require the introduction of new dynamical scalar fields or modifications to general relativity, and it can be tested by astronomical observations in the near future.Comment: 31 pages, 4 figures; v2: version accepted by Phys. Rev.

    Signal-specific amplitude adjustment to noise in common bottlenose dolphins (Tursiops truncatus)

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    Fieldwork in Sarasota was funded by the Grossman Foundation, the Office of Naval Research, and Woods Hole Oceanographic Institution. Health assessments were funded by Dolphin Quest, Inc. I.M.K. received support from the Danish Acoustical Society (Dansk Akustisk Selskab). P.L.T. received funding from the University of St Andrews, the Office of Naval Research (N00014-19-1-2560) and the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). F.H.J. was supported by the Office of Naval Research (N00014-1410410) and an AIAS-COFUND fellowship from Aarhus Institute of Advanced Studies under the FP7-PEOPLE programme of the EU (agreement no. 609033). All support is gratefully acknowledged.Anthropogenic underwater noise has increased over the past century, raising concern about the impact on cetaceans that rely on sound for communication, navigation and locating prey and predators. Many terrestrial animals increase the amplitude of their acoustic signals to partially compensate for the masking effect of noise (the Lombard response), but it has been suggested that cetaceans almost fully compensate with amplitude adjustments for increasing noise levels. Here, we used sound-recording DTAGs on pairs of free-ranging common bottlenose dolphins (Tursiops truncatus) to test (i) whether dolphins increase signal amplitude to compensate for increasing ambient noise and (ii) whether adjustments are identical for different signal types. We present evidence of a Lombard response in the range 0.1–0.3 dB per 1 dB increase in ambient noise, which is similar to that of terrestrial animals, but much lower than the response reported for other cetaceans. We found that signature whistles tended to be louder and with a lower degree of amplitude adjustment to noise compared with non-signature whistles, suggesting that signature whistles may be selected for higher output levels and may have a smaller scope for amplitude adjustment to noise. The consequence of the limited degree of vocal amplitude compensation is a loss of active space during periods of increased noise, with potential consequences for group cohesion, conspecific encounter rates and mate attraction.Publisher PDFPeer reviewe
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