887 research outputs found
Moduli Stabilization with Long Winding Strings
Stabilizing all of the modulus fields coming from compactifications of string
theory on internal manifolds is one of the outstanding challenges for string
cosmology. Here, in a simple example of toroidal compactification, we study the
dynamics of the moduli fields corresponding to the size and shape of the torus
along with the ambient flux and long strings winding both internal directions.
It is known that a string gas containing states with non-vanishing winding and
momentum number in one internal direction can stabilize the radius of this
internal circle to be at self-dual radius. We show that a gas of long strings
winding all internal directions can stabilize all moduli, except the dilaton
which is stabilized by hand, in this simple example.Comment: title changed, improved presentation; reference added. 18 pages, JHEP
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Orbiting Resonances and Bound States in Molecular Scattering
A family of orbiting resonances in molecular scattering is globally described
by using a single pole moving in the complex angular momentum plane. The
extrapolation of this pole at negative energies gives the location of the bound
states. Then a single pole trajectory, that connects a rotational band of bound
states and orbiting resonances, is obtained. These complex angular momentum
singularities are derived through a geometrical theory of the orbiting. The
downward crossing of the phase-shifts through pi/2, due to the repulsive region
of the molecular potential, is estimated by using a simple hard-core model.
Some remarks about the difference between diffracted rays and orbiting are also
given.Comment: 18 pages, 3 figures, to appear in Physical Review
On the dust properties of high-redshift molecular clouds and the connection to the 2175 Å extinction bump
On the dust properties of high-redshift molecular clouds and the connection to the 2175 Å extinction bump
We present a study of the extinction and depletion-derived dust properties of
gamma-ray burst (GRB) absorbers at showing the presence of neutral
carbon (\ion{C}{I}). By modelling their parametric extinction laws, we discover
a broad range of dust models characterizing the GRB \ion{C}{I} absorption
systems. In addition to the already well-established correlation between the
amount of \ion{C}{I} and visual extinction, , we also observe a
correlation with the total-to-selective reddening, . All three quantities
are also found to be connected to the presence and strength of the 2175\,{\AA}
dust extinction feature. While the amount of \ion{C}{I} is found to be
correlated with the SED-derived dust properties, we do not find any evidence
for a connection with the depletion-derived dust content as measured from
[Zn/Fe] and (Fe). To reconcile this, we discuss a scenario
where the observed extinction is dominated by the composition of dust particles
confined in the molecular gas-phase of the ISM. We argue that since the
depletion level trace non-carbonaceous dust in the ISM, the observed extinction
in GRB \ion{C}{I} absorbers is primarily produced by carbon-rich dust in the
molecular cloud and is therefore only observable in the extinction curves and
not in the depletion patterns. This also indicates that the 2175\,{\AA} dust
extinction feature is caused by dust and molecules in the cold and molecular
gas-phase. This scenario provides a possible resolution to the discrepancy
between the depletion- and SED-derived amounts of dust in high- absorbers.Comment: 10 pages, 5 Figs. + Appendix. Accepted in MNRA
Weather, disease, and wheat breeding effects on Kansas wheat varietal yields, 1985 to 2011.
Wheat (Triticum aestivum L.) yields in Kansas have increased due to wheat breeding and improved agronomic practices, but are subject to climate and disease challenges. The objective of this research is to quantify the impact of weather, disease, and genetic improvement on wheat yields of varieties grown in 11 locations in Kansas from 1985 to 2011. Wheat variety yield data from Kansas performance tests were matched with comprehensive location-specific disease and weather data, including seasonal precipitation, monthly air temperature, air temperature and solar radiation around anthesis, and vapor pressure deficit (VPD). The results show that wheat breeding programs increased yield by 34 kg ha⁻¹ yr⁻¹. From 1985 through 2011, wheat breeding increased average wheat yields by 917 kg ha⁻¹, or 27% of total yield. Weather was found to have a large impact on wheat yields. Simulations demonstrated that a 1°C increase in projected mean temperature was associated with a decrease in wheat yields of 715 kg ha⁻¹, or 21%. Weather, diseases, and genetics all had significant impacts on wheat yields in 11 locations in Kansas during 1985 to 2011
Community advisory boards guiding engaged research efforts within a clinical translational sciences award: Key contextual factors explored
Background: Engaging stakeholders in research carries the promise of enhancing the research relevance, transparency, and speed of getting findings into practice. By describing the context and functional aspects of stakeholder groups, like those working as community advisory boards (CABs), others can learn from these experiences and operationalize their own CABs. Our objective is to describe our experiences with diverse CABs affiliated with our community engagement group within our institution’s Clinical Translational Sciences Award (CTSA). We identify key contextual elements that are important to administering CABs. Methods: A group of investigators, staff, and community members engaged in a 6-month collaboration to describe their experiences of working with six research CABs. We identified the key contextual domains that illustrate how CABS are developed and sustained. Two lead authors, with experience with CABs and identifying contextual domains in other work, led a team of 13 through the process. Additionally, we devised a list of key tips to consider when devising CABs. Results: The final domains include (1) aligned missions among stakeholders (2) resources/support, (3) defined operational processes/shared power, (4) well-described member roles, and (5) understanding and mitigating challenges. The tips are a set of actions that support the domains. Conclusions: Identifying key contextual domains was relatively easy, despite differences in the respective CAB’s condition of focus, overall mission, or patient demographics represented. By contextualizing these five domains, other research and community partners can take an informed approach to move forward with CAB planning and engaged research
Criterion A of the AMPD in HiTOP
The categorical model of personality disorder classification in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (5th ed. [DSM-5]; American Psychiatric Association, 2013) is highly and fundamentally problematic. Proposed for DSM-5 and provided within Section III (for Emerging Measures and Models) was the Alternative Model of Personality Disorder (AMPD) classification, consisting of Criterion A (self-interpersonal deficits) and Criterion B (maladaptive personality traits). A proposed alternative to the DSM-5 more generally is an empirically based dimensional organization of psychopathology identified as the Hierarchical Taxonomy of Psychopathology (HiTOP; Kotov etal., 2017). HiTOP currently includes, at the highest level, a general factor of psychopathology. Further down are the five domains of detachment, antagonistic externalizing, disinhibited externalizing, thought disorder, and internalizing (along with a provisional sixth somatoform dimension) that align with Criterion B. The purpose of this article is to discuss the potential inclusion and placement of the self-interpersonal deficits of the DSM-5 Section III Criterion A within HiTOP
Complex relationships among personality traits, job characteristics, and work behaviors
The aim of the study was to investigate the additive, mediating, and moderating effects of personality traits and job characteristics on work behaviors. Job applicants (N = 161) completed personality questionnaires measuring extraversion, neuroticism, achievement motivation, and experience seeking. One and a half years later, supervisors rated the applicants' job performance, and the job incumbents completed questionnaires about skill variety, autonomy, and feedback, work stress, job satisfaction, work self-efficacy, and propensity to leave. LISREL was used to test 15 hypotheses. Perceived feedback mediated the relationship between achievement motivation and job performance. Extraversion predicted work self-efficacy and job satisfaction. Work stress mediated the relationship between neuroticism and job satisfaction. Job satisfaction and experience seeking were related to propensity to leave. Autonomy, skill variety, and feedback were related to job satisfaction
Demonstration of the temporal matter-wave Talbot effect for trapped matter waves
We demonstrate the temporal Talbot effect for trapped matter waves using
ultracold atoms in an optical lattice. We investigate the phase evolution of an
array of essentially non-interacting matter waves and observe matter-wave
collapse and revival in the form of a Talbot interference pattern. By using
long expansion times, we image momentum space with sub-recoil resolution,
allowing us to observe fractional Talbot fringes up to 10th order.Comment: 17 pages, 7 figure
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