Bounded H_\infty-calculus for pseudodifferential Douglis-Nirenberg systems of mild regularity

Parameter-ellipticity with respect to a closed subsector of the complex plane for pseudodifferential Douglis-Nirenberg systems is discussed and shown to imply the existence of a bounded H_\infty-calculus in suitable scales of Sobolev, Besov, and Hoelder spaces. We also admit non pseudodifferential perturbations. Applications concern systems with coefficients of mild Hoelder regularity and the generalized thermoelastic plate equations.Comment: 22 page

Pinning forces of sliding drops at defects

Wetting of surfaces depends critically on defects which alter the shape of the drop. However, no experimental verification of forces owing to the three phase contact line deformation at single defects is available. We imaged the contact line of sliding drops on hydrophobic surfaces by video microscopy. From the deformation of the contact line, we calculate the force acting on a sliding drop using an equation going back to Joanny and de Gennes (J. Chem. Phys., 81 (1984) 554). The calculated forces quantitatively agree with directly measured forces acting between model defects and water drops. In addition, both forces quantitatively match with the force calculated by contact angle differences between the defect and the surface. The quantitative agreement even holds for defects reaching a size of $40\%$ of the drop diameter. Our validation for drop’s pinning forces at single defects is an important step towards a general understanding of contact line motion on heterogeneous surfaces

A Clash of Old and New Scientific Concepts in Toxicity, with Important Implications for Public Health

Background A core assumption of current toxicologic procedures used to establish health standards for chemical exposures is that testing the safety of chemicals at high doses can be used to predict the effects of low-dose exposures, such as those common in the general population. This assumption is based on the precept that “the dose makes the poison”: higher doses will cause greater effects. Objectives We challenge the validity of assuming that high-dose testing can be used to predict low-dose effects for contaminants that behave like hormones. We review data from endocrinology and toxicology that falsify this assumption and summarize current mechanistic understanding of how low doses can lead to effects unpredictable from high-dose experiments. Discussion Falsification of this assumption raises profound issues for regulatory toxicology. Many exposure standards are based on this assumption. Rejecting the assumption will require that these standards be reevaluated and that procedures employed to set health standards be changed. The consequences of these changes may be significant for public health because of the range of health conditions now plausibly linked to exposure to endocrine-disrupting contaminants. Conclusions We recommend that procedures to establish acceptable exposure levels for endocrine-disrupting compounds incorporate the inability for high-dose tests to predict low-dose results. Setting acceptable levels of exposure must include testing for health consequences at prevalent levels of human exposure, not extrapolations from the effects observed in high-dose experiments. Scientists trained in endocrinology must be engaged systematically in standard setting for endocrine-disrupting compounds

Benefits of soy-based feeds for fetal estrogen levels and obesity in adulthood

Abstract only availableWe examined the effect of maternal exposure to naturally occurring estrogenic chemicals in diets on circulating levels of estradiol in mouse fetuses. An animal's specific response to estrogen can vary according to the time of exposure. The time when the fetus is sensitive to permanent “programming” effects of estrogen is called a “critical period” in development of organ systems. An important factor in the regulation of estrogen in the fetus is the composition of the mother's diet. Our hypothesis was that if a diet that was fed to pregnant mice during the fetal critical period contained estrogenic chemicals, these chemicals would “estrogenize” the fetus. In contrast to this prediction, a casein-based diet with virtually no estrogenic chemicals led to significantly higher levels of endogenous estradiol relative to a soy-based diet with very high levels of estrogenic chemicals. In a follow-up experiment we compared a soy-based diet containing estrogenic chemicals with a soy-based diet from which these estrogenic chemicals were extracted. The complete soy diet resulted in estrodiol levels of 60 pg/ml in fetal serum, while the extracted soy diet dramatically increased serum estradiol by over 50%. This finding shows that the naturally occurring estrogens in soy (phytoestrogens) fed to pregnant mice reduce endogenous estradiol levels in the fetuses. This is important since elevated levels of estradiol during fetal life "program" certain characteristics into the animal later on in adulthood. One of these characteristics is obesity. Obesity is associated with Type II diabetes, and the mice with elevated fetal estradiol levels show evidence of impaired glucose tolerance in later adulthood. These effects are relevant since obesity and diabetes are abnormalities in humans that are increasing.Life Sciences Undergraduate Research Opportunity Progra

Maternal effects on anogenital distance in a wild marmot population

Peer reviewedPublisher PD

Secondary School Counselors’ Perceptions of Service-Learning: Gaps between State Policy, Counselors’ Knowledge, and Implementation

The purpose of this study was a state-level investigation of school counselors’ knowledge of their role in the implementation of service-learning policy using survey research methods. The respondents reported having little knowledge of the policy, not having implemented it statewide, and not having been trained in service-learning pedagogy. Based on these results, this article provides implications for consideration when states develop educational policies that impact school counselors’ work

Pb isotopic variability in melt inclusions from the EMI–EMII–HIMU mantle end-members and the role of the oceanic lithosphere

Melt inclusions from four individual lava samples representing the HIMU (Mangaia Island), EMI (Pitcairn Island) and EMII (Tahaa Island) end member components, have heterogeneous Pb isotopic composition larger than that defined by the erupted lavas in each island. The broad linear trend in ^(207)Pb/^(206)Pb–^(208)Pb/^(206)Pb space produced by the melt inclusions from Mangaia, Tahaa and fPitcairn samples reproduces the entire trend defined by the Austral chain, the Society islands and the Pitcairn island and seamount groups. The inclusions preserve a record of melt composition of far greater isotopic diversity than that sampled in whole rock basalts. These results can be explained by mixing of a common depleted component with the HIMU, EMI and EMII lavas, respectively. We favor a model that considers the oceanic lithosphere to be that common component. We suggest that the Pb isotopic compositions of the melt inclusions reflect wall rock reaction of HIMU, EMI and EMII melts during their percolation through the oceanic lithosphere. Under these conditions, the localized rapid crystallization of olivine from primitive basalt near the reaction zone would allow the entrapment of melt inclusions with different isotopic composition

Long-wavelength approximation for string cosmology with barotropic perfect fluid

The field equations derived from the low energy string effective action with a matter tensor describing a perfect fluid with a barotropic equation of state are solved iteratively using the long-wavelength approximation, i.e. the field equations are expanded by the number of spatial gradients. In the zero order, a quasi-isotropic solution is presented and compared with the general solution of the pure dilaton gravity. Possible cosmological models are analyzed from the point of view of the pre-big bang scenario. The second order solutions are found and their growing and decaying parts are studied.Comment: 19 pages, 1 figur

Assessing the effectiveness of business support services in England: evidence from a theory based evaluation

In England, publicly supported advisory services for small firms are organised primarily through the Business Link (BL) network. Based on the programme theory underlying this business support services we develop four propositions and test these empirically using data from a new survey of over 3,000 English small firms. Our empirical results provide a broad validation of the programme theory underlying BL assistance for small firms in England during 2003, and more limited support for its effectiveness. More specifically, we find strong support for the value of BL operators maintaining a high profile as a way of boosting take-up. We also find some support for the approach to market segmentation adopted by BL allowing more intensive assistance to be targeted on younger firms and those with limited liability status. In terms of the outcomes of BL support, and allowing for issues of sample selection, we find no significant effects on growth from ‘other’ assistance but do find positive and significant employment growth effects from intensive assistance. This provides partial support for the programme theory assertion that BL support will lead to improvements in business growth performance and stronger support for the proposition that there would be differential outcomes from intensive and other assistance. The positive employment growth outcomes identified here from intensive assistance, even allowing for sample selection, suggest something of an improvement in the effectiveness of the BL network since the late 1990s