18,164 research outputs found
Dynamics of hadron strong production and decay
We generalize results of lattice QCD to determine the spin-dependent
symmetries and factorization properties of meson production in OZI allowed
processes. This explains some conjectures previously made in the literature
about axial meson decays and gives predictions for exclusive decays of vector
charmonia, including ways of establishing the structure of Y(4260) and Y(4325)
from their S-wave decays. Factorization gives a selection rule which forbids
near threshold with the tensor meson in helicity 2. The
relations among amplitudes for double charmonia production \e^+e^-\to
\psi\chi_{0,1,2} are expected to differ from the analagous relations among
light flavour production such as \e^+e^-\to \omega f_{0,1,2}.Comment: 13 pages; journal versio
Trust and Conservation Opportunity: the importance of trust in landholders\u27 decisions to participate in conservation programs
Natural resource management efforts have historically concentrated on ecological goals to identify and prioritize conservation actions. However, successful implementation of conservation actions on private land requires conservation opportunity, or the willingness of landholders to participate in and accept conservation actions. Conservation opportunity on private land depends on a range of structural and social factors. Recent research emphasizes the importance of social factors and suggests incorporating social factors in conservation actions is necessary for the long-term sustainability and equitability of environmental change. The social factor of trust has been shown to strongly influence landholderâs decision-making. For this research, trust is defined as a belief that someone or something is good, reliable, honest, and effective. However, trust is complex and sometimes difficult to predict. In addition, trust can be regionally specific and little research exists on trust in the Pacific Northwest.
This study seeks to increase understanding of trust and the importance of trust in conservation opportunity on private land in the Pacific Northwest. In this study, trust is comprised of six constructs: Personal Relationship, Social Structure, Reciprocity, Shared Worldview, Social Commitment, and Participation in Decision-Making. The researcher utilized self-administered surveys to measure landholdersâ level of trust in conservation organizations and answer three research questions: Are the constructs associated with trust as expected? Which constructs of trust are most important in a landholderâs decision to participate in voluntary conservation programs? and What actions could these organizations take to improve trust?
Surveys were distributed to participants and non-participants of four voluntary conservation programs in the Nooksack Watershed in Whatcom County, Washington. The research results suggest six primary findings. First, survey respondents report trust as equally or more important than other factors in determining conservation opportunity. Second, not all individuals have a uniform definition of trust, yet trust is strongly associated with the degree to which the landholder perceives an individual, institution, or program respects and understands their goals. Third, results distinguish two constructs being reported as most important in determining conservation opportunity within the study group: Social Commitment and Participation in Decision-Making. The construct items reported as least important are affiliation with other groups/individuals and obligation. Fourth, while the landholderâs relationship with the organizationâs representative is important, they do not identify it as the most influential construct item. Fifth, although the literature shows the Shared Worldview construct can predict policy positions, the results of a Shared Worldview âshort-formâ survey indicate worldview may not be a predictor for who participates and what program they will participate in. Finally, both participants and non-participants believe the conservation organizations have the opportunity to earn or increase trust. Landholdersâ suggested actions to increase trust varied but included providing long-term on-the-ground work, improved communication, additional opportunities for landholder input, changes to the organizationâs governance, and effort to change state policy. While results cannot be extended to the general population, the findings have the potential to help conservation organizations within the Pacific Northwest build trust with landholders and increase landholder enrollment in conservation programs. In addition, the findings highlight areas for future research
The association between life events, social support, and antibody status following thymus-dependent and thymus-independent vaccinations in healthy young adults
This study determined whether stressful life events and social support were related to antibody status following both thymus-dependent and thymus-independent vaccinations. Life events in the previous year and customary social support were measured in 57 healthy students at baseline. Antibody status was also assessed at baseline and at five weeks and five months following vaccination with the trivalent influenza vaccine and the meningococcal A+C polysaccharide vaccine. Taking into account baseline antibody titre, high life events scores prior to vaccination were associated with lower responses to the B/Shangdong influenza strain at both five weeks and five months and meningococcal C at five weeks. Life events scores were not associated with response to the other two influenza viral strains nor response to meningococcal A. Those with high social support scores had stronger 5-week and 5-month antibody responses to the A/Panama influenza strain, but not to any of the other strains. These associations could not be accounted for by demographic or health behaviour factors, and also emerged from analyses comparing those who exhibited a four-fold increase in antibody titre from baseline with those who did not. Life events and social support were related to antibody status following influenza vaccination in distinctive ways that may be partly determined by vaccine novelty and prior naturalistic exposure. Life events also predicted poor antibody response to meningococcal C polysaccharide vaccination after previous meningococcal C conjugate vaccination. Neither psychosocial factor was associated with response to primary meningococcal A polysaccharide vaccination
A Universal Temperature Profile for Galaxy Clusters
We investigate the predicted present-day temperature profiles of the hot,
X-ray emitting gas in galaxy clusters for two cosmological models - a current
best-guess LCDM model and standard cold dark matter (SCDM). Our
numerically-simulated "catalogs" of clusters are derived from high-resolution
(15/h kpc) simulations which make use of a sophisticated, Eulerian-based,
Adaptive Mesh-Refinement (AMR) code that faithfully captures the shocks which
are essential for correctly modelling cluster temperatures. We show that the
temperature structure on Mpc-scales is highly complex and non-isothermal.
However, the temperature profiles of the simulated LCDM and SCDM clusters are
remarkably similar and drop-off as
where and . This decrease
is in good agreement with the observational results of Markevitch et al.(1998)
but diverges, primarily in the innermost regions, from their fit which assumes
a polytropic equation of state. Our result is also in good agreement with a
recent sample of clusters observed by BeppoSAX though there is some indication
of missing physics at small radii (). We discuss the
interpretation of our results and make predictions for new x-ray observations
that will extend to larger radii than previously possible. Finally, we show
that, for , our universal temperature profile is consistent with
our most recent simulations which include both radiative cooling and supernovae
feedback.Comment: 8 pages, 6 figures, accepted for publication in ApJ, full-page
version of Fig. 2 at
http://www.cita.utoronto.ca/+AH4-cloken/PAPERS/UTP/f2.ep
Investigation of resin systems for improved ablative materials Interim report, 10 Jan. - 1 Jul. 1966
Preparation, and evaluation of polyimide sulfone resins, graphite-silica reinforced polyamide resins, and resin resistance to FLOX- methane, and fluorine-hydrogen fuel
Canopy Characteristics, Ingestive Behaviour and Herbage Intake in Cultivated Tropical Grasslands
Compared to temperate systems, there have been few detailed assessments of canopy characteristics and associated grazing behavior in planted tropical grasslands. Reasons include the large number of forage species used in warm climates, the diversity of their morphology, research priorities emphasizing germplasm evaluation and management, and limited resources. This review describes canopy attributes of C4 grass pastures, highlights the most important relationships between grazing behavior and these canopy characteristics, and discusses the implications of canopy characteristics and grazing behavior for long-term intake and animal performance. It is suggested that the largest differences in canopy characteristics between tropical and temperate swards are not total canopy measures but those of the upper canopy strata including leaf proportion and bulk density. This occurs because tropical swards, unlike many temperate ones, have large vertical heterogeneity in density, plant-part proportion and nutritive value. In temperate swards, bite weight is primarily a function of sward height, but leaf percentage, leaf mass, or green herbage mass of the upper strata of the canopy usually are more important with C4 grasses. The manner in which leaf is presented to the animal and the degree to which it can be prehended separate from stem and dead material of low digestibility are also of great significance in pastures based on C4 grasses
An event study to provide validation of TING and CMIT geomagnetic middle-latitude electron densities at the F2 peak
[1] The coupled thermosphere-ionosphere magnetosphere (CMIT) model and the Thermosphere Ionosphere Nested Grid (TING) model have been run to simulate the 15 May 1997 interplanetary coronal mass ejection\u27s (ICME) effects on the Earth\u27s ionosphere and thermosphere. Comparisons were made between these model runs, the IRI-2007 model, and geomagnetic middle-latitude ionosonde data (NmF2) from the World Data Center to determine how well the models simulated the event and to understand the causes of model-data disagreement. The following conclusions were drawn from this study: (1) skill scores were more often negative than positive on average; (2) the best and the worst skill scores occurred on the recovery day; (3) the line plots comparing models to data look better than the skill scores might suggest; (4) skill scores are significantly affected by timing issues and large, short-duration variability; (5) skill scores give an indication of the relative ability of one model relative to another, rather than an absolute statement of model accuracy; (6) the models capture negative storm effects better than they capture positive storm effects; (7) the TING model captured many short duration features seen in the data at high middle latitude stations that result from changes in the size of the auroral oval; (8) CMIT overestimates the energy driving changes in NmF2, whereas TING provides approximately the correct energy input as a result of the saturation effects on potential that are included in TING; and (9) both TING and CMIT electron densities decreased too rapidly after sunset
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