Neutrino mass and low-temperature calorimetry

We describe how the problem of measuring the neutrino mass led us to the development of low-temperature calorimetry. The search for a "17-keV neutrino" concluded with a negative result, but a wide range of applications are now carried on by us and by other groups in the fields of x-ray astronomy, recoil measurements of dark matter particles, high precision particle spectrometry, specific heat determinations, neutron detection, rare decay studies. The masses of the bolometers (calorimeters) extend from 1 mg to 1 Kg, nearly as large as for quantum detectors. By lowering the temperature into the 10-20 mK range, calorimetry is on the way to surpass substantially the high precision of particle metrology obtainable with the quantum detectors. Calorimeter developments and perspectives are discussed

Histopathology and selective biomarker expression in human meibomian glands

BACKGROUND/AIMS: Meibomian gland dysfunction (MGD) is the most common form of evaporative dry eye disease, but its pathogenesis is poorly understood. This study examined the histopathological features of meibomian gland (MG) tissue from cadaver donors to identify potential pathogenic processes that underlie MGD in humans. METHODS: Histological analyses was performed on the MGs in the tarsal plates dissected from four cadaver donors, two young and two old adults, including a 36-year-old female (36F) and three males aged 30, 63 and 64 years (30M, 63M and 64M). RESULTS: The MGs of 36F displayed normal anatomy and structure, whereas the MGs of 30M showed severe ductal obstruction with mild distortion. The obstruction was caused by increased cytokeratin levels in association with hyperproliferation, but not hyperkeratinisation. In two older males, moderate to severe MG atrophy was noted. Cell proliferation was significantly reduced in the MG acini of the two older donors as measured by Ki67 labelling index (6.0%±3.4% and 7.9%±2.8% in 63M and 64M, respectively) when compared with that of the two younger donors (23.2%±5.5% and 16.9%±4.8% in 30M and 36F, respectively) (p\u3c0.001). The expression patterns of meibocyte differentiation biomarkers were similar in the older and younger donors. CONCLUSION: Our histopathological study, based on a small sample size, suggests potentially distinct pathogenic mechanisms in MGD. In the young male adult, hyperproliferation and aberrant differentiation of the central ductal epithelia may lead to the obstruction by overproduced cytokeratins. In contrast, in older adults, decreased cell proliferation in acinar basal epithelia could be a contributing factor leading to MG glandular atrophy

Phenology and Biomass Production of Adapted and Non-Adapted Tropical Corn Populations in Central Iowa

Biofuel production in the midwestern United States has largely focused on corn (Zea mays L.) grain for ethanol production and more recently, corn stover for lignocellulosic ethanol. Tropical corn refers to corn adapted from tropical regions. Growing tropical germplasm in temperate environments is not attractive for grain yield, but shows promise for biomass production through taller and more vigorous plants with thick stems and long leaves. The comparison between tropical corn populations and their temperate adapted counterparts with a focus on biomass production has not yet been explored under Iowa growing conditions. This study refines the accuracy of the leaf collar method, and characterizes the adaptation of the populations by evaluating crop development and biomass production. Therefore, field trials were established in central Iowa during the 2014 and 2015 growing seasons. Adapted and non-adapted versions of three populations, Tuxpeño, Suwan, and Tuson, were planted at three dates to evaluate their phenology and potential for biomass production under midwestern U.S. conditions. Plant height correlated well with vegetative development and total biomass. Adapted tropical corn had advanced grain development, while non-adapted tropical corn had advanced vegetative development and greater biomass yield. Non-adapted tropical corn flowered later, had 22% greater total biomass on average (4.6 Mg ha–1 greater than adapted), and had 43% greater non-grain biomass on average, up to 20 Mg ha–1 (6 Mg ha–1 greater than adapted), while adapted populations yielded more grain. Non-adapted tropical corn has a high potential as feedstock for Gen2 biofuels in central Iowa

On the Conductance Sum Rule for the Hierarchical Edge States of the Fractional Quantum Hall Effect

The conductance sum rule for the hierarchical edge channel currents of a Fractional Quantum Hall Effect state is derived analytically within the Haldane-Halperin hierarchy scheme. We provide also an intuitive interpretation for the hierarchical drift velocities of the edge excitations.Comment: 11 pages, no figure, Revtex 3.0, IC/93/329, ASITP-93-5

Weakly Nonlinear AC Response: Theory and Application

We report a microscopic and general theoretical formalism for electrical response which is appropriate for both DC and AC weakly nonlinear quantum transport. The formalism emphasizes the electron-electron interaction and maintains current conservation and gauge invariance. It makes a formal connection between linear response and scattering matrix theory at the weakly nonlinear level. We derive the dynamic conductance and predict the nonlinear-nonequilibrium charge distribution. The definition of a nonlinear capacitance leads to a remarkable scaling relation which can be measured to give microscopic information about a conductor

Evolution of entanglement for quantum mixed states

A simple relation is introduced for concurrence to describe how much the entanglement of bipartite system is at least left if either (or both) subsystem undergoes an arbitrary physical process. This provides a lower bound for concurrence of mixed states (pure states are included) in contrast to the upper bound given by Konrad et al [Nature Physics \textbf{4}, 99 (2008)]. Our results are also suitable for a general high dimensional bipartite quantum systems.Comment: 6 pages and 1 figur

Intense duskside lower band chorus waves observed by Van Allen Probes: Generation and potential acceleration effect on radiation belt electrons

Abstract Local acceleration driven by whistler mode chorus waves largely accounts for the enhancement of radiation belt relativistic electron fluxes, whose favored region is usually considered to be the plasmatrough with magnetic local time approximately from midnight through dawn to noon. On 2 October 2013, the Van Allen Probes recorded a rarely reported event of intense duskside lower band chorus waves (with power spectral density up to 10-3nT 2/Hz) in the low-latitude region outside of L=5. Such chorus waves are found to be generated by the substorm-injected anisotropic suprathermal electrons and have a potentially strong acceleration effect on the radiation belt energetic electrons. This event study demonstrates the possibility of broader spatial regions with effective electron acceleration by chorus waves than previously expected. For such intense duskside chorus waves, the occurrence probability, the preferential excitation conditions, the time duration, and the accurate contribution to the long-term evolution of radiation belt electron fluxes may need further investigations in future

Prediagnostic Plasma Vitamin D Metabolites and Mortality among Patients with Prostate Cancer

Laboratory evidence suggests that vitamin D might influence prostate cancer prognosis.We examined the associations between prediagnostic plasma levels of 25(OH)vitamin D [25(OH)D] and 1,25(OH)(2) vitamin D [1,25(OH)(2)D] and mortality among 1822 participants of the Health Professionals Follow-up Study and Physicians' Health Study who were diagnosed with prostate cancer. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) of total mortality (n = 595) and lethal prostate cancer (death from prostate cancer or development of bone metastases; n = 202). In models adjusted for age at diagnosis, BMI, physical activity, and smoking, we observed a HR of 1.22 (95% CI: 0.97, 1.54) for total mortality, comparing men in the lowest to the highest quartile of 25(OH)D. There was no association between 1,25(OH)(2)D and total mortality. Men with the lowest 25(OH)D quartile were more likely to die of their cancer (HR: 1.59; 95% CI: 1.06, 2.39) compared to those in the highest quartile (P(trend) = 0.006). This association was largely explained by the association between low 25(OH)D levels and advanced cancer stage and higher Gleason score, suggesting that these variables may mediate the influence of 25(OH)D on prognosis. The association also tended to be stronger among patients with samples collected within five years of cancer diagnosis. 1,25(OH)(2)D levels were not associated with lethal prostate cancer.Although potential bias of less advanced disease due to more screening activity among men with high 25(OH)D levels cannot be ruled out, higher prediagnostic plasma 25(OH)D might be associated with improved prostate cancer prognosis