Critical behavior of ion mobilities near the superfluid transition

Measurements are reported of the mobilities of helium ions in superfluid helium very close to the λ transition. The mobilities of both positive and negative ions appear to be singular in the sense of having infinite slope at the transition. The measurements are made by a new differential technique, based on the space-charge-limited method, which makes possible a sensitivity to changes in mobility of the order of parts in 104. This allows mobility measurements into the range |ε|<10-4, where ε=(T/Tλ)-1. Most of the reported measurements are taken along isotherms which cross the λ line at elevated pressures, although a series at saturated vapor pressure is also reported. Means of transforming the data between various thermodynamic paths are discussed. Uncertainty as to which thermodynamic path should be considered fundamental together with experimental problems in the technique at this stage in its development make quantitative assessment of the singularity difficult. However, if we assume a limiting form (μ-μλ)/μλ∼(-ε)ρ′, where μ is the mobility and μλ its value at the transition, we find for the exponent ρ′=0.94±0.02

A Conceptual Framework to Measure Systems’ Performance during Emergency Preparedness Exercises

Large-scale public health emergencies require a sophisticated, coordinated response involving multiple entities to protect health and minimize suffering. However, the rarity of such emergencies presents a barrier to gathering observational data about the effectiveness of the public health response before such events occur. For this reason, public health practitioners increasingly have relied on simulated emergencies, known as “exercises” as proxies to test their emergency capabilities. However, the formal evaluation of performance in these exercises, historically has been inconsistent, and there is little research to describe how data acquired from simulated emergencies actually support conclusions about the quality of the public health emergency response system. Over the past six years, we have designed and evaluated more than seventy public health emergency exercises, collaborating with public health agencies, hospitals and others to test a wide variety of systems and their capabilities. Using the data and experience that we gathered, we have developed a conceptual framework that describes the essential elements necessary to consider when applying performance measurement science to public health emergency exercises. We suggest that this framework may assist practitioners and researchers who wish to better measure performance in exercises and to improve public health emergency preparedness

Federico Cesi's Mycological Codex and its copies

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Polar catastrophe and electronic reconstructions at the LaAlO3/SrTiO3 interface: evidence from optical second harmonic generation

The so-called "polar catastrophe", a sudden electronic reconstruction taking place to compensate for the interfacial ionic polar discontinuity, is currently considered as a likely factor to explain the surprising conductivity of the interface between the insulators LaAlO3 and SrTiO3. We applied optical second harmonic generation, a technique that a priori can detect both mobile and localized interfacial electrons, to investigating the electronic polar reconstructions taking place at the interface. As the LaAlO3 film thickness is increased, we identify two abrupt electronic rearrangements: the first takes place at a thickness of 3 unit cells, in the insulating state; the second occurs at a thickness of 4-6 unit cells, i.e., just above the threshold for which the samples become conducting. Two possible physical scenarios behind these observations are proposed. The first is based on an electronic transfer into localized electronic states at the interface that acts as a precursor of the conductivity onset. In the second scenario, the signal variations are attributed to the strong ionic relaxations taking place in the LaAlO3 layer

Risk-communication capability for public health emergencies varies by community diversity

<p>Abstract</p> <p>Background</p> <p>Public health emergencies heighten several challenges in risk-communication: providing trustworthy sources of information, reaching marginalized populations, and minimizing fear and public confusion. In emergencies, however, information may not diffuse equally among all social groups, and gaps in knowledge may increase. Such knowledge gaps vary by social structure and the size, socioeconomic status, and diversity of the population. This study explores the relationship between risk-communication capabilities, as perceived by public officials participating in emergency tabletop exercises, and community size and diversity.</p> <p>Findings</p> <p>For each of the three communication functions tested, risk-communication capabilities are perceived to be greater in communities with fewer then 10% of the population speaking a language other than English at home, decreasing as the percentage grows to 20% (ANOVA P ≤ 0.02). With respect to community size, however, we found an N-shaped relationship between perceived risk communication capabilities and population size. Capabilities are perceived highest in the largest communities and lowest in the smallest, but lower in communities with 20,000–49,999 inhabitants compared to those with 2,500–19,999.</p> <p>Conclusion</p> <p>The results of this study suggest the need to factor population diversity into risk communication plans and the need for improved state or regional risk-communication capabilities, especially for communities with limited local capacity.</p

COUNTERVAILING VASCULAR EFFECTS OF ROSIGLITAZONE IN HIGH CARDIOVASCULAR RISK MICE: ROLE OF OXIDATIVE STRESS AND PRMT-1.

In the present study, we tested the hypothesis that the PPARgamma (peroxisome-proliferator-activated receptor gamma) activator rosiglitazone improves vascular structure and function in aged hyperhomocysteinaemic MTHFR (methylene tetrahydrofolate reductase) gene heterozygous knockout (mthfr+/-) mice fed a HCD (high-cholesterol diet), a model of high cardiovascular risk. One-year-old mthfr+/- mice were fed or not HCD (6 mg x kg-1 of body weight x day-1) and treated or not with rosiglitazone (20 mg x kg-1 of body weight x day-1) for 90 days and compared with wild-type mice. Endothelium-dependent relaxation of carotid arteries was significantly impaired (-40%) only in rosiglitazone-treated HCD-fed mthfr+/- mice. Carotid M/L (media-to-lumen ratio) and CSA (cross-sectional area) were increased (2-fold) in mthfr+/- mice fed or not HCD compared with wild-type mice (P<0.05). Rosiglitazone reduced M/L and CSA only in mthfr+/- mice fed a normal diet. Superoxide production was increased in mthfr+/- mice fed HCD treated or not with rosiglitazone, whereas plasma nitrite was decreased by rosiglitazone in mice fed or not HCD. PRMT-1 (protein arginine methyltransferase-1), involved in synthesis of the NO (nitric oxide) synthase inhibitor ADMA (asymmetric omega-NG,NG-dimethylarginine), and ADMA were increased only in rosiglitazone-treated HCD-fed mthfr+/- mice. Rosiglitazone had both beneficial and deleterious vascular effects in this animal model of high cardiovascular risk: it prevented carotid remodelling, but impaired endothelial function in part through enhanced oxidative stress and increased ADMA production in mice at high cardiovascular risk

R705H mutation of MYH9 is associated with MYH9-related disease and not only with non-syndromic deafness DFNA17

MYH9-related disease (MYH9-RD) is a rare autosomal dominant disease caused by mutation of MYH9, the gene encoding for the heavy chain of non-muscle myosin IIA (NMMHC-IIA). MYH9-RD patients have macrothrombocytopenia and granulocyte inclusions (pathognomonic sign of the disease) containing wild-type and mutant NMMHC-IIA. During life they might develop sensorineural hearing loss, cataract, glomerulonephritis, and elevation of liver enzymes. One of the MYH9 mutations, p.R705H, was previously reported to be associated with DFNA17, an autosomal dominant non-syndromic sensorineural hearing loss without any other features associated. We identified the same mutation in two unrelated families, whose four affected individuals had not only hearing impairment but also thrombocytopenia, giant platelets, leukocyte inclusions, as well as mild to moderate elevation of some liver enzymes. Our data suggest that DFNA17 should not be a separate genetic entity but part of the wide phenotypic spectrum of MYH9-RD characterized by congenital hematological manifestations and variable penetrance and expressivity of the extra-hematological features

Viscosity and positive-ion mobility near the melting transition in liquid ^4He

New measurements are presented of the shear viscosity η and the positive-ion mobility μ near the melting transition in liquid 4He. Interpreted in terms of the Stokes law for the drag on a sphere in a viscous medium, it is found, contrary to expectation, that the effective radius of the ion remains constant or decreases slightly as the melting transition is approached at constant temperature. Attempts to explain this observation have not been successful. On the other hand, an older mystery concerning the effective radius of the ion is cleared up: Ahlers and Gamota, comparing data for η and μ at the vapor pressure curve found that the effective radius has a maximum 40 mK below the λ transition (i.e., the lower triple point). We have observed a similar maximum on the melting curve, 40 mK below the upper triple point. It is shown that these maxima may be accounted for by an electrostrictively induced λ transition around the ion. In this interpretation, the maximum along the melting curve serves as the first empirical evidence that the λ line extends into the region of supercooled liquid at pressures above the melting curve