1,716 research outputs found
Do negative random shocks affect trust and trustworthiness?
We report data from a variation of the trust game aimed at determining whether (and how) inequality and random shocks that affect wealth influence the levels of trust and trustworthiness. To tease apart the effect of the shock and the inequality, we compare behavior in a trust game where the inequality is initially given and one where it is the result of a random shock that reduces the second moverâs endowment. We find that first-movers send less to second-movers but only when the inequality results from a random shock. As for the amount returned, second-movers return less when they are endowed less than first-movers, regardless of whether the difference in endowments was initially given or occurred after a random shock
Trust and trustworthiness after negative random shocks
We experimentally investigate the effect of a negative endowment shock that can cause inequality in a trust game. Our goal is to assess whether different causes of inequality have different effects on trust and trustworthiness. In our trust game, we vary whether there is inequality (in favor of the second mover) or not and whether the inequality results from a random negative shock (i.e., the outcome of a die roll) or exists from the outset. Our findings suggest that inequality causes first-movers to send more of their endowment and second-movers to return more. However, we do not find support for the hypothesis that the cause of the inequality matters. Behavior after the occurrence of a random shock is not significantly different from the behavior in treatments where the inequality exists from the outset. Our results highlight the need to be cautious when interpreting the effects on trust and trustworthiness of negative random shocks in the field (such as natural disasters). Our results suggest that these effects are primarily driven by the inequality caused by the shock and not by any of the additional characteristics of the shock, like saliency or uncertainty
Melting and Pressure-Induced Amorphization of Quartz
It has recently been shown that amorphization and melting of ice were
intimately linked. In this letter, we infer from molecular dynamics simulations
on the SiO2 system that the extension of the quartz melting line in the
metastable pressure-temperature domain is the pressure-induced amorphization
line. It seems therefore likely that melting is the physical phenomenon
responsible for pressure induced amorphization. Moreover, we show that the
structure of a "pressure glass" is similar to that of a very rapidly (1e+13 to
1e+14 kelvins per second) quenched thermal glass.Comment: 9 pages, 4 figures, LaTeX2
A combined XAS and XRD Study of the High-Pressure Behaviour of GaAsO4 Berlinite
Combined X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD)
experiments have been carried out on GaAsO4 (berlinite structure) at high
pressure and room temperature. XAS measurements indicate four-fold to six-fold
coordination changes for both cations. The two local coordination
transformations occur at different rates but appear to be coupled. A reversible
transition to a high pressure crystalline form occurs around 8 GPa. At a
pressure of about 12 GPa, the system mainly consists of octahedral gallium
atoms and a mixture of arsenic in four-fold and six-fold coordinations. A
second transition to a highly disordered material with both cations in six-fold
coordination occurs at higher pressures and is irreversible.Comment: 8 pages, 5 figures, LaTeX2
Big Line Bundles over Arithmetic Varieties
We prove a Hilbert-Samuel type result of arithmetic big line bundles in
Arakelov geometry, which is an analogue of a classical theorem of Siu. An
application of this result gives equidistribution of small points over
algebraic dynamical systems, following the work of Szpiro-Ullmo-Zhang. We also
generalize Chambert-Loir's non-archimedean equidistribution
The whole and its parts : why and how to disentangle plant communities and synusiae in vegetation classification
Most plant communities consist of different structural and ecological subsets, ranging from cryptogams to different tree layers. The completeness and approach with which these subsets are sampled have implications for vegetation classification. Nonâvascular plants are often omitted or sometimes treated separately, referring to their assemblages as âsynusiaeâ (e.g. epiphytes on bark, saxicolous species on rocks). The distinction of complete plant communities (phytocoenoses or holocoenoses) from their parts (synusiae or merocoenoses) is crucial to avoid logical problems and inconsistencies of the resulting classification systems. We here describe theoretical differences between the phytocoenosis as a whole and its parts, and outline consequences of this distinction for practise and terminology in vegetation classification. To implement a clearer separation, we call for modifications of the International Code of Phytosociological Nomenclature and the EuroVegChecklist. We believe that these steps will make vegetation classification systems better applicable and raise the recognition of the importance of nonâvascular plants in the vegetation as well as their interplay with vascular plants
High-pressure investigations of CaTiO3 up to 60 GPa using X-ray diffraction and Raman spectroscopy
In this work, we investigate calcium titanate (CaTiO3 - CTO) using X-ray
diffraction and Raman spectroscopy up to 60 and 55 GPa respectively. Both
experiments show that the orthorhombic Pnma structure remains stable up to the
highest pressures measured, in contradiction to ab-initio predictions. A fit of
the compression data with a second-order Birch-Murnaghan equation of state
yields a bulk modulus K0 of 181.0(6) GPa. The orthorhombic distortion is found
to increase slightly with pressure, in agreement with previous experiments at
lower pressures and the general rules for the evolution of perovskites under
pressure. High-pressure polarized Raman spectra also enable us to clarify the
Raman mode assignment of CTO and identify the modes corresponding to rigid
rotation of the octahedra, A-cation shifts and Ti-O bond stretching. The Raman
signature is then discussed in terms of compression mechanisms.Comment: 11 pages, 6 figures, 4 table
Constructible motivic functions and motivic integration
We introduce a direct image formalism for constructible motivic functions.
One deduces a very general version of motivic integration for which a change of
variables theorem is proved. These constructions are generalized to the
relative framework, in which we develop a relative version of motivic
integration. These results have been announced in math.AG/0403349 and
math.AG/0403350.
Main results and statements unchanged. Many minor slips corrected and some
details added.Comment: Final versio
The usefulness of rapid diagnostic tests in the new context of low malaria transmission in zanzibar.
BACKGROUND\ud
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We assessed if histidine-rich-protein-2 (HRP2) based rapid diagnostic test (RDT) remains an efficient tool for Plasmodium falciparum case detection among fever patients in Zanzibar and if primary health care workers continue to adhere to RDT results in the new epidemiological context of low malaria transmission. Further, we evaluated the performance of RDT within the newly adopted integrated management of childhood illness (IMCI) algorithm in Zanzibar.\ud
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METHODS AND FINDINGS\ud
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We enrolled 3890 patients aged â„2 months with uncomplicated febrile illness in this health facility based observational study conducted in 12 primary health care facilities in Zanzibar, between May-July 2010. One patient had an inconclusive RDT result. Overall 121/3889 (3.1%) patients were RDT positive. The highest RDT positivity rate, 32/528 (6.1%), was found in children aged 5-14 years. RDT sensitivity and specificity against PCR was 76.5% (95% CI 69.0-83.9%) and 99.9% (95% CI 99.7-100%), and against blood smear microscopy 78.6% (95% CI 70.8-85.1%) and 99.7% (95% CI 99.6-99.9%), respectively. All RDT positive, but only 3/3768 RDT negative patients received anti-malarial treatment. Adherence to RDT results was thus 3887/3889 (99.9%). RDT performed well in the IMCI algorithm with equally high adherence among children <5 years as compared with other age groups.\ud
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CONCLUSIONS\ud
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The sensitivity of HRP-2 based RDT in the hands of health care workers compared with both PCR and microscopy for P. falciparum case detection was relatively low, whereas adherence to test results with anti-malarial treatment was excellent. Moreover, the results provide evidence that RDT can be reliably integrated in IMCI as a tool for improved childhood fever management. However, the relatively low RDT sensitivity highlights the need for improved quality control of RDT use in primary health care facilities, but also for more sensitive point-of-care malaria diagnostic tools in the new epidemiological context of low malaria transmission in Zanzibar.\ud
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TRIAL REGISTRATION\ud
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ClinicalTrials.gov NCT01002066
Angular versus radial correlation effects on momentum distributions of light two-electron ions
We investigate different correlation mechanisms for two-electron systems and
compare their respective effects on various electron distributions. The
simplicity of the wave functions used allows for the derivation of closed-form
analytical expressions for all electron distributions. Among other features, it
is shown that angular and radial correlation mechanisms have opposite effects
on Compton profiles at small momenta.Comment: 22 pages, 5 figures, 3 tabl
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