77 research outputs found
Towards a high precision calculation for the pion-nucleus scattering lengths
We calculate the leading isospin conserving few-nucleon contributions to pion
scattering on H, He, and He. We demonstrate that the strong
contributions to the pion-nucleus scattering lengths can be controlled
theoretically to an accuracy of a few percent for isoscalar nuclei and of 10%
for isovector nuclei. In particular, we find the -He scattering length
to be where the uncertainties are
due to ambiguities in the -N scattering lengths and few-nucleon effects,
respectively. To establish this accuracy we need to identify a suitable power
counting for pion-nucleus scattering. For this purpose we study the dependence
of the two-nucleon contributions to the scattering length on the binding energy
of H. Furthermore, we investigate the relative size of the leading two-,
three-, and four-nucleon contributions. For the numerical evaluation of the
pertinent integrals, aMonte Carlo method suitable for momentum space is
devised. Our results show that in general the power counting suggested by
Weinberg is capable to properly predict the relative importance of -nucleon
operators, however, it fails to capture the relative strength of - and
-nucleon operators, where we find a suppression by a factor of 5
compared to the predicted factor of 50. The relevance for the extraction of the
isoscalar -N scattering length from pionic H and He is discussed.
As a side result, we show that beyond the calculation of the -H
scattering length is already beyond the range of applicability of heavy pion
effective field theory.Comment: 24 pages, 14 figures, 10 table
Seasonal effects on reconciliation in Macaca Fuscata Yakui
Dietary composition may have profound effects on the activity budgets, levelof food competition, and social behavior of a species. Similarly, in seasonally breeding species, the mating season is a period in which competition for mating partners increases, affecting amicable social interactions among group members. We analyzed the importance of the mating season and of seasonal variations in dietary composition and food competition on econciliation
in wild female Japanese macaques (Macaca fuscata yakui) on Yakushima Island, Japan. Yakushima macaques are appropriate subjects because they are seasonal breeders and their dietary composition significantly changes among the seasons. Though large differences occurred between the summer months and the winter and early spring months in activity budgets and the consumption of the main food sources, i.e., fruits, seeds, and leaves, the level
of food competition and conciliatory tendency remained unaffected. Conversely,conciliatory tendency is significantly lower during the mating season than in the nonmating season. Moreover, conciliatory tendency is lower when 1 or both female opponents is in estrous than when they are not. Thus the mating season has profound effects on reconciliation, whereas seasonal changes in activity budgets and dietary composition do not. The detrimental effects of the mating season on female social relationships and reconciliation may be due to the importance of female competition for access to male partners in multimale, multifemale societies
Decreased expression of cardiac troponin C is associated with cardiac lesions in Amorimia exotropica poisoned cattle
The plants which cause sudden death of cattle in Brazil occupy a leading position for losses in the cattle industry. Amorimia exotropica is one of the plants pertaining to this group. Diagnostic findings in these cases may be inconclusive; further knowledge is necessary. This paper identifies cardiac lesions through anti-cardiac troponin C (cTnC) immunehistochemistry performed in tissues from cattle poisoned after consumption of A.exotropica in southern Brazil. Heart fragments from nine A. exotropica-poisoned cattle were studied immunohistochemically using anti-human cTnC as the primary antibody. In the hearts from all of the poisoned cattle, there was a sharp decrease in the cTnC expression level in the cytoplasm of groups of cardiomyocytes. A significant decrease in anti-cTnC immunoreactivity occurred particularly in degenerated or necrotic cardiomyocytes. Occasional groups of cells showed complete loss of immunolabeling. In the remaining intact cardiomyocytes from poisoned cattle and in cardiomyocytes from six cattle that died from other causes there was intense cytoplasmic staining
Addressing climate change with behavioral science:A global intervention tournament in 63 countries
Effectively reducing climate change requires marked, global behavior change. However, it is unclear which strategies are most likely to motivate people to change their climate beliefs and behaviors. Here, we tested 11 expert-crowdsourced interventions on four climate mitigation outcomes: beliefs, policy support, information sharing intention, and an effortful tree-planting behavioral task. Across 59,440 participants from 63 countries, the interventions' effectiveness was small, largely limited to nonclimate skeptics, and differed across outcomes: Beliefs were strengthened mostly by decreasing psychological distance (by 2.3%), policy support by writing a letter to a future-generation member (2.6%), information sharing by negative emotion induction (12.1%), and no intervention increased the more effortful behavior-several interventions even reduced tree planting. Last, the effects of each intervention differed depending on people's initial climate beliefs. These findings suggest that the impact of behavioral climate interventions varies across audiences and target behaviors.</p
Addressing climate change with behavioral science:A global intervention tournament in 63 countries
Effectively reducing climate change requires marked, global behavior change. However, it is unclear which strategies are most likely to motivate people to change their climate beliefs and behaviors. Here, we tested 11 expert-crowdsourced interventions on four climate mitigation outcomes: beliefs, policy support, information sharing intention, and an effortful tree-planting behavioral task. Across 59,440 participants from 63 countries, the interventions' effectiveness was small, largely limited to nonclimate skeptics, and differed across outcomes: Beliefs were strengthened mostly by decreasing psychological distance (by 2.3%), policy support by writing a letter to a future-generation member (2.6%), information sharing by negative emotion induction (12.1%), and no intervention increased the more effortful behavior-several interventions even reduced tree planting. Last, the effects of each intervention differed depending on people's initial climate beliefs. These findings suggest that the impact of behavioral climate interventions varies across audiences and target behaviors.</p
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