344 research outputs found

    A New Centrosaurine Ceratopsid, Machairoceratops cronusi gen et sp. nov., from the Upper Sand Member of the Wahweap Formation (Middle Campanian), Southern Utah

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    The Upper Cretaceous (middle-late Campanian) Wahweap Formation of southern Utah contains the oldest diagnostic evidence of ceratopsids (to date, all centrosaurines) in North America, with a number of specimens recovered from throughout a unit that spans between 81 and 77 Ma. Only a single specimen has been formally named, Diabloceratops eatoni, from the lower middle member of the formation. Machairoceratops cronusi gen. et sp. nov., a new centrosaurine ceratopsid from the upper member of the Wahweap Formation, is here described based on cranial material representing a single individual recovered from a calcareous mudstone. The specimen consists of two curved and elongate orbital horncores, a left jugal, a nearly complete, slightly deformed braincase, the left squamosal, and a mostly complete parietal ornamented by posteriorly projected, anterodorsally curved, elongate spikes on either side of a midline embayment. The fan-shaped, stepped-squamosal is diagnostic of Centrosaurinae, however, this element differs from the rectangular squamosal in Diabloceratops. Machairoceratops also differs in the possession of two anterodorsally (rather than laterally) curved epiparietal ornamentations on either side of a midline embayment that are distinguished by a posteromedially-oriented sulcus along the entire length of the epiparietal. Additionally, the parietosquamosal frill is lacking any other epiossifications along its periphery. Machairoceratops shares a triangular (rather than round) frill and spikelike epiparietal loci (p1) ornamentation with the stratigraphically lower Diabloceratops. Both parsimony and Bayesian phylogenetic analyses place Machairoceratops as an earlybranching centrosaurine. However, the parsimony-based analysis provides little resolution for the position of the new taxon, placing it in an unresolved polytomy with Diabloceratops. The resultant Bayesian topology yielded better resolution, aligning Machairoceratops as the definitive sister taxon to a clade formed by Diabloceratops and Albertaceratops. Considered together, both phylogenetic methods unequivocally place Machairoceratops as an early-branching centrosaurine, and given the biostratigraphic position of Machairoceratops, these details increase the known ceratopsid diversity from both the Wahweap Formation and the southern portion of Laramidia. Finally, the unique morphology of the parietal ornamentation highlights the evolutionary disparity of frill ornamentation near the base of Centrosaurinae.The research was supported by the Bureau of Land Management (Grand Staircase-Escalante National Monument), the Ohio University Heritage College of Osteopathic Medicine, the Ohio University Office of the Vice President for Research and Creative Activity, and the US National Science Foundation (EAR 0745454, 0819953).SP201

    Satisfaction with life after partner loss: Time-varying and time-invariant components and their associations with prolonged grief

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    Background: Recovery after the death of a loved one involves decreasing sadness and grief, but also involves maintaining and strengthening satisfaction with life (SWL). Greater SWL may buffer the development of emotional problems following loss, including symptoms of prolonged grief. There is limited knowledge on how SWL may develop following loss and how it relates to such symptoms. The aim of this study was to examine to what extent SWL following partner-loss was characterized by time-invariant (trait-like) and time-varying (state-like) components and to examine associations of these components with long-term prolonged grief.  Method: Data were available from elderly bereaved people who lost their partner. They provided self-reported data on SWL at two, six, 13, 18 and 48 months post-loss and rated prolonged grief severity at 48 months. Latent trait-state-occasion (TSO) modeling was employed to distinguish the time-invariant and time-varying components of SWL. Regression analysis tested associations of these components with prolonged grief at 48 months.  Results: In this sample, SWL consisted of significant time-invariant and time-varying components. The time-varying components were larger than the time-invariant component at 4 of 5 assessment points. At 48 months post-loss, the time-varying component of SWL was more strongly associated with concurrently assessed prolonged grief than was its time-invariant component.  Conclusion: After partner loss, SWL appears to be more strongly “state-like” than “trait-like”. This suggests that it may be successfully boosted by external influences (including bereavement care interventions)

    Entanglement in spin-1/2 dimerized Heisenberg systems

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    We study entanglement in dimerized Heisenberg systems. In particular, we give exact results of ground-state pairwise entanglement for the four-qubit model by identifying a Z_2 symmetry. Although the entanglements cannot identify the critical point of the system, the mean entanglement of nearest-neighbor qubits really does, namely, it reaches a maximum at the critical point.Comment: Four pages, three figures, accepted in Communications in Theoretical Physic

    Synchronously pumped mid-infrared CdSe optical parametric oscillator

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    Synchronously pumped optical parametric oscillators (SPOPOs) are efficient sources of tunable ultrashort pulses, with low threshold average power requirements, since gain is defined by peak power. An attractive material for such devices is cadmium selenide (CdSe) due to its high nonlinearity (d(31) = 18 pm/V), wide transparency range (0.75-25 ”m) and high optical quality. Previous efforts involving CdSe in OPOs have been restricted to angle-tuning, and using Q-switched pump sources. We present here the first continuous-wave, mode-locked SPOPO based on non-critically phase-matched (NCPM) CdSe, with agile tuning of the idler over the range 9.1-9.7 ”m, the longest wavelength achieved using a SPOPO to date. Pump-wavelength-tuning over a wide range (necessary for the NCPM arrangement) was provided by the signal output of a periodically poled lithium niobate (PPLN) SPOPO, operating close to degeneracy using a single PPLN grating period. The use of a diffraction grating to tune the signal of the PPLN SPOPO was a key factor in obtaining clean, single-frequency pump conditions, with tuning achieved by simple grating rotation

    An interactive 3D virtual environment to reduce the public speaking anxiety levels of novice software engineers

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    Software engineering is a set of activities that relies no only on technical tasks but also requires abilities focused on social duties such as daily meetings and product introduction presentations. However, engineers may experience elevated levels of anxiety when required to present their work in an unfamiliar environment. More specifically, they may suffer from public speaking anxiety even though they are supposed to be effective in those social tasks as well as in their engineering activities. Fortunately, previous studies suggest that virtual exposure therapy is an effective strategy to reduce public speaking anxiety. In this study, an interactive 3D virtual environment similar to real classrooms and auditoriums was developed to examine if this might decrease the anxiety levels of novice software engineers. To compare traditional and virtual exposure therapy, the sample set (N = 14) was divided equally into 2 groups including one experimental group and one control group. For 4 weeks, the virtual exposure therapy was conducted in the experimental group whereas psychoeducation was used in the control group. The findings from our study illustrate that virtual exposure therapy may be represent an alternative solution to the traditional therapeutic intervention for software engineers seeking to overcome public presentation anxiet

    Theory of finite temperature crossovers near quantum critical points close to, or above, their upper-critical dimension

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    A systematic method for the computation of finite temperature (TT) crossover functions near quantum critical points close to, or above, their upper-critical dimension is devised. We describe the physics of the various regions in the TT and critical tuning parameter (tt) plane. The quantum critical point is at T=0T=0, t=0t=0, and in many cases there is a line of finite temperature transitions at T=Tc(t)T = T_c (t), t<0t < 0 with Tc(0)=0T_c (0) = 0. For the relativistic, nn-component ϕ4\phi^4 continuum quantum field theory (which describes lattice quantum rotor (n≄2n \geq 2) and transverse field Ising (n=1n=1) models) the upper critical dimension is d=3d=3, and for d<3d<3, Ï”=3−d\epsilon=3-d is the control parameter over the entire phase diagram. In the region ∣T−Tc(t)∣â‰ȘTc(t)|T - T_c (t)| \ll T_c (t), we obtain an Ï”\epsilon expansion for coupling constants which then are input as arguments of known {\em classical, tricritical,} crossover functions. In the high TT region of the continuum theory, an expansion in integer powers of Ï”\sqrt{\epsilon}, modulo powers of lnâĄÏ”\ln \epsilon, holds for all thermodynamic observables, static correlators, and dynamic properties at all Matsubara frequencies; for the imaginary part of correlators at real frequencies (ω\omega), the perturbative Ï”\sqrt{\epsilon} expansion describes quantum relaxation at ℏω∌kBT\hbar \omega \sim k_B T or larger, but fails for ℏω∌ϔkBT\hbar \omega \sim \sqrt{\epsilon} k_B T or smaller. An important principle, underlying the whole calculation, is the analyticity of all observables as functions of tt at t=0t=0, for T>0T>0; indeed, analytic continuation in tt is used to obtain results in a portion of the phase diagram. Our method also applies to a large class of other quantum critical points and their associated continuum quantum field theories.Comment: 36 pages, 4 eps figure

    Activated Transport in AMTEC Electrodes

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    Transport of alkali metal atoms through porous cathodes of alkali metal thermal-to-electric converter (AMTEC) cells is responsible for significant, reducible losses in the electrical performance of these cells. Experimental evidence for activated transport of metal atoms at grain surfaces and boundaries within some AMTEC electrodes has been derived from temperature dependent studies as well as from analysis of the detailed frequency dependence of ac impedance results for other electrodes, including thin, mature molybdenum electrodes which exhibit transport dominated by free molecular flow of sodium gas at low frequencies or dc conditions. Activated surface transport will almost always exist in parallel with free molecular flow transport, and the process of alkali atom adsorption/desorption from the electrode surface will invariably be part of the transport process, and possibly a dominant part in some cases. Little can be learned about the detailed mass transport process from the ac impedance or current voltage curves of an electrode at one set of operating parameters, because the transport process includes a number of important physical parameters that are not all uniquely determined by one experiment. The temperature dependence of diffusion coefficient of the alkali metal through the electrode in several cases provides an activation energy and pre-exponential, but at least two activated processes may be operative, and the activation parameters should be expected to depend on the alkali metal activity gradient that the electrode experiences. In the case of Pt/W/Mn electrodes operated for 2500 hours, limiting currents varied with electrode thickness, and the activation parameters could be assigned primarily to the surface/grain boundary diffusion process. 17 refs

    The Paranormal is (Still) Normal: The Sociological Implications of a Survey of Paranormal Experiences in Great Britain

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    Historically, there has been limited sociological interest in the paranormal and no systematic study of reported paranormal experiences. There are also few medium-to-large-scale survey results with nationally representative populations focusing on paranormal experiences. This paper provides details of an exploratory survey conducted in 2009 with a nationally representative sample of 4,096 adults aged 16 years and over across Great Britain. Our findings show that 37% of British adults report at least one paranormal experience and that women, those who are middle-aged or individuals resident in the South West are more likely to report such experiences. These results establish incidence levels of reported paranormal experiences in contemporary Britain. We argue also that they merit a more sustained sociological consideration of the paranormal. In this respect we renew and update the robust justification and call for serious research positioning the paranormal as a social phenomenon, originally proposed well over thirty years ago by Greeley (1975)

    The longitudinal association of actigraphy-estimated sleep with grief in middle-aged and elderly persons

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    Most people experience grief after a loss, about 10% develop complicated grief, often accompanied by sleep complaints. Yet, the role of objectively estimated poor sleep remains unclear. Therefore, we assessed the cross-sectional and longitudinal association of actigraphy-estimated sleep with grief. We included 1,776 participants (mean age: 61.8 ± 8.9 years, 55% women) of a prospective population-based cohort. Of 1,471 participants (83%) repeated measures of grief were available (median follow-up 6 years, inter quartile range 5.6–6.3). At baseline, sleep was objectively estimated using actigraphy (mean duration 6.0 ± 0.8days). At baseline and follow-up, participants were asked about significant losses and completed the Dutch Inventory of Complicated Grief (17 items, cut-off ≄22). At baseline 1,521 (86%) participants experienced no grief, 44 (2%) acute grief (<6 months, any grief score), 158 (9%) non-complicated grief (≄6 months, grief score<22), and 53 (3%) complicated grief (≄6 months, grief score≄22). In those indicating any grief (n = 255), low sleep efficiency (B = −0.16, 95%CI = −0.30;-0.02), long sleep onset latency (B = 0.07, 95%CI = 0.01; 0.14), and long wake after sleep onset (B = 0.06, 95%CI = 0.01; 0.10) were cross-sectionally associated with more grief symptoms. Over time, those with a short total sleep time (OR = 0.59, 95%CI = 0.39; 0.91), low sleep efficiency (OR = 0.95, 95%CI = 0.91; 0.99), long sleep onset latency (OR = 1.02, 95%CI = 1.00; 1.04), and long wake after sleep onset (OR = 1.02, 95%CI = 1.00; 1.03) at baseline more often experienced complicated grief than non-complicated grief at follow-up. This study suggests that objectively estimated poor sleep is associated with grief over time. Poor sleep might not only accompany grief, but also be a risk factor for developing complicated grief after a loss
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