Absence of Cyclotron Resonance in the Anomalous Metallic Phase in InO_{x}.

It is observed that many thin superconducting films with not too high disorder level (generally R_{N}/□<2000 Ω) placed in magnetic field show an anomalous metallic phase where the resistance is low but still finite as temperature goes to zero. Here we report in weakly disordered amorphous InO_{x} thin films that this anomalous metal phase possesses no cyclotron resonance and hence non-Drude electrodynamics. The absence of a finite frequency resonant mode can be associated with a vanishing downstream component of the vortex current parallel to the supercurrent and an emergent particle-hole symmetry of this metal, which establishes its non-Fermi-liquid character.

Coherent quantum phase slip.

A hundred years after the discovery of superconductivity, one fundamental prediction of the theory, coherent quantum phase slip (CQPS), has not been observed. CQPS is a phenomenon exactly dual to the Josephson effect; whereas the latter is a coherent transfer of charges between superconducting leads, the former is a coherent transfer of vortices or fluxes across a superconducting wire. In contrast to previously reported observations of incoherent phase slip, CQPS has been only a subject of theoretical study. Its experimental demonstration is made difficult by quasiparticle dissipation due to gapless excitations in nanowires or in vortex cores. This difficulty might be overcome by using certain strongly disordered superconductors near the superconductor-insulator transition. Here we report direct observation of CQPS in a narrow segment of a superconducting loop made of strongly disordered indium oxide; the effect is made manifest through the superposition of quantum states with different numbers of flux quanta. As with the Josephson effect, our observation should lead to new applications in superconducting electronics and quantum metrology.

Instability of Insulators near Quantum Phase Transitions.

Thin films of amorphous indium oxide undergo a magnetic field driven superconducting to insulator quantum phase transition. In the insulating phase, the current-voltage characteristics show large current discontinuities due to overheating of electrons. We show that the onset voltage for the discontinuities vanishes as we approach the quantum critical point. As a result, the insulating phase becomes unstable with respect to any applied voltage making it, at least experimentally, immeasurable. We emphasize that unlike previous reports of the absence of linear response near quantum phase transitions, in our system, the departure from equilibrium is discontinuous. Because the conditions for these discontinuities are satisfied in most insulators at low temperatures, and due to the decay of all characteristic energy scales near quantum phase transitions, we believe that this instability is general and should occur in various systems while approaching their quantum critical point. Accounting for this instability is crucial for determining the critical behavior of systems near the transition.

Nonequilibrium Second-Order Phase Transition in a Cooper-Pair Insulator.

In certain disordered superconductors, upon increasing the magnetic field, superconductivity terminates with a direct transition into an insulating phase. This phase is comprised of localized Cooper pairs and is termed a Cooper-pair insulator. The current-voltage characteristics measured in this insulating phase are highly nonlinear and, at low temperatures, exhibit abrupt current jumps. Increasing the temperature diminishes the jumps until the current-voltage characteristics become continuous. We show that a direct correspondence exists between our system and systems that undergo an equilibrium, second-order, phase transition. We illustrate this correspondence by comparing our results to the van der Waals equation of state for the liquid-gas mixture. We use the similarities to identify a critical point where an out of equilibrium second-order-like phase transition occurs in our system. Approaching the critical point, we find a power-law behavior with critical exponents that characterizes the transition.

Differences in homeostatic model assessment (HOMA) values and insulin levels after vitamin D supplementation in healthy men: a double-blind randomized controlled trial.

Vitamin D is thought to play a role in glucose metabolism. The aim of the present study was to determine the effect of vitamin D supplementation on markers of insulin sensitivity and inflammation in men without diabetes with vitamin D deficiency/insufficiency. In this 1-year double-blind randomized controlled trial, 130 men aged 20-65 years (mean age 47.52 ± 11.84 years) with serum 25-hydroxyvitamin D levels <50 nmol/l (mean 38.89 ± 8.64 nmol/l) were randomized to treatment (100 000 IU vitamin D bimonthly) or placebo. Anthropometric measurements, demographic questionnaires, and blood indices (fasting glucose, insulin, high-sensitivity C-reactive protein, lipids) were collected and repeated after 6 and 12 months. The compliance rate was 98.5%. Multivariate models, adjusted for baseline levels, age, body mass index, sun exposure, physical activity and LDL, showed significant differences in insulin and homeostatic model assessment of insulin resistance (HOMA-IR) values between groups. Levels of insulin and HOMA-IR values remained steady during the study period in the treatment group but increased by 16% in the control group (p = 0.038 and p = 0.048, respectively). Vitamin D supplementation administered for 12 months in healthy men maintained insulin levels and HOMA-IR values relative to the increase in the control group. Further studies are needed to establish the long-term effect of vitamin D supplementation on the risk of diabetes.

Identifying the threshold for vitamin D insufficiency in relation to cardiometabolic markers.

BACKGROUND AND AIMS: To determine the association between vitamin D status and cardiometabolic indicators, and to determine the vitamin threshold that affects these parameters. METHODS AND RESULTS: High-tech employees were recruited from a periodic occupational health examination clinic and via the study's website. Diastolic and systolic blood pressure (DBP, SBP), body mass index (BMI), and waist circumference were measured. Serum concentrations of 25(OH)D, fasting plasma insulin (FPI), fasting plasma glucose (FPG), triglycerides (TG), and high sensitive C-Reactive Protein (hs-CRP) were measured in fasting blood samples. Of the 400 men who agreed to participate, 358 (90%) completed the study. Mean age was 48.8 ± 10.2 y, BMI 27.0 ± 3.8 k/m(2), serum 25(OH)D 22.1 ± 7.9 ng/l. Deficiency (defined as serum 25(OH)D < 12 ng/ml) was observed among 10.6%, 29.9% were insufficient (12 < 25(OH)D < 20 ng/ml), and 59.5% had sufficient levels (25(OH)D > 20 ng/ml). BMI, waist circumference, FPI, HOMA-IR, TG, hs-CRP levels, DBP, and SBP were negatively associated with serum 25(OH)D. A curved linear association was found with insulin and HOMA-IR with a significant spline knot at 11 ng/ml. For hs-CRP a spline knot at 14 ng/ml was observed. TG, SBP, and DBP exhibited linear associations with 25(OH)D. CONCLUSIONS: Vitamin D status is related to cardiometabolic indicators in healthy men. We suggest a 25(OH)D threshold of 11-14 ng/ml for these outcomes. Future studies are required to address temporal relationships and the impact of vitamin D supplementation.

Measurement of a superconducting energy gap in a homogeneously amorphous insulator.

We present tunneling spectroscopy measurements that directly reveal the existence of a superconducting gap in the insulating state of homogenously disordered amorphous indium oxide films. Two films on both sides of the disorder induced superconductor to insulator transition show the same energy gap scale. This energy gap persists up to relatively high magnetic fields and is observed across the magnetoresistance peak typical of disordered superconductors. The results provide useful information for understanding the nature of the insulating state in the disorder induced superconductor to insulator transition.

Little-Parks oscillations in an insulator.

We present the results of a magnetoresistance study of the disorder-induced superconductor-insulator transition in an amorphous indium-oxide thin film patterned by a nanoscale periodic array of holes. We observed Little-Parks-like oscillations over our entire range of disorder spanning the transition. The period of oscillations was unchanged and corresponded to the superconducting flux quantum in the superconducting as well as in the insulating phases. Our results provide direct evidence for electron pairing in the insulator bordering with superconductivity.

The critical current of disordered superconductors near 0 K.

An increasing current through a superconductor can result in a discontinuous increase in the differential resistance at the critical current. This critical current is typically associated either with breaking of Cooper-pairs or with the onset of collective motion of vortices. Here we measure the current-voltage characteristics of superconducting films at low temperatures and high magnetic fields. Using heat-balance considerations we demonstrate that the current-voltage characteristics are well explained by electron overheating enhanced by the thermal decoupling of the electrons from the host phonons. By solving the heat-balance equation we are able to accurately predict the critical currents in a variety of experimental conditions. The heat-balance approach is universal and applies to diverse situations from critical currents to climate change. One disadvantage of the universality of this approach is its insensitivity to the details of the system, which limits our ability to draw conclusions regarding the initial departure from equilibrium.

Dietary factors in relation to daily activity energy expenditure and mortality among older adults.

OBJECTIVES: To examine the association between dietary factors to daily activity energy expenditure (DAEE) and mortality among older adults. DESIGN AND SETTING: A sub-study of Health, Aging, and Body Composition study. PARTICIPANTS: 298 older participants (aged 70-82 years) in the Health, Aging, and Body Composition Energy Expenditure sub-study. MEASUREMENTS: Dietary factors, DAEE, and all-cause mortality were measured in 298 older participants. Dietary factors include dietary intake assessed by the Block Food Frequency Questionnaire (FFQ), Healthy Eating Index (HEI), and self-reported appetite and enjoyment of eating. DAEE was assessed using doubly labeled water. All-cause mortality was evaluated over a 9 year period. RESULTS: Participants in the highest tertile of DAEE were more likely to be men and to report having a 'good' appetite; BMI among men, proportion married, IL-6 and CRP levels and energy intake were also higher. Fewer black participants were in the 'good' HEI category. Participants in the 'good' HEI category had higher cognitive scores and a higher education level. Participants who reported improvement in their appetite as well as participants who reported a 'good' appetite were at lower risk for mortality (HR (95% CI): 0.42 (0.24-0.74) and 0.50 (0.26-0.88), respectively) even after adjusting for DAEE, demographic, nutritional and health indices. CONCLUSIONS: We showed an association between DAEE and appetite and mortality among well-functioning, community-dwelling older adults. These findings may have some practical use for the health providers. Inclusion of a question regarding appetite of an elderly patient may provide important information regarding risk for health deterioration and mortality.

Sensitivity of the superconducting state in thin films.

For more than two decades, there have been reports on an unexpected metallic state separating the established superconducting and insulating phases of thin-film superconductors. To date, no theoretical explanation has been able to fully capture the existence of such a state for the large variety of superconductors exhibiting it. Here, we show that for two very different thin-film superconductors, amorphous indium oxide and a single crystal of 2H-NbSe2, this metallic state can be eliminated by adequately filtering external radiation. Our results show that the appearance of temperature-independent, metallic-like transport at low temperatures is sufficiently described by the extreme sensitivity of these superconducting films to external perturbations. We relate this sensitivity to the theoretical observation that, in two dimensions, superconductivity is only marginally stable.

Depressive symptoms and risk for malnutrition among hospitalized elderly people.

OBJECTIVES: To explore the association between depressive symptoms and risk for malnutrition in hospitalized elderly people. METHODS: 195 hospitalized medical patients older than 65 years of age were studied in a cross-sectional design. Depression was assessed by 30-item Geriatric Depression Scale (GDS), nutritional status was evaluated by the Mini-Nutritional Assessment (MNA). Eating and digestive problems were assessed using selected items of Nutrition Risk Index (NRI), cognitive and functional status by Folstein and Barthel indices respectively; demographic data, diagnoses and medications were obtained from medical records. RESULTS: The prevalence of depression in the studied population was 28%. MNA scores were significantly lower among depressed patients as compared with non-depressed (22.86 vs. 24.96, p < 0.001), indicating a higher risk for undernutrition among depressed persons. After controlling for age, cognitive status, functional ability, and number of illnesses, undernutrition was significantly associated with depression (OR = 2.23; 95% CI: 1.04-4.8). CONCLUSIONS: Nutritional risk is associated with depression in aged inpatients. Close case management of the elderly hospitalized patients that include assessment and treatment for both disorders may be beneficial.

Factors associated with low reported energy intake in the elderly.

BACKGROUND: Underreporting of dietary intake can be estimated by the Energy Ratio (ER) between reported energy intake (EI) and calculated total energy expenditure (TEE). The gap between EI and TEE is usually attributed to underreporting. In elderly populations, compromised dietary intake and health status may offer alternative explanations to this gap. OBJECTIVE: This study aimed to characterize "underreporting" of dietary intake and low energy reporters (LER) among the elderly. DESIGN: Participants aged 65 years and over, were recruited using random population sampling of the Negev population. Data were collected using the 24-h recall method with additional demographic and age-specific health questionnaires. ER was calculated using the ratio between reported energy intake and calculated TEE computed by the Schofield formula. LER were defined as those with reported energy intake of less than 0.8 calculated BMR using the Schofield formula. RESULTS: We restricted our analysis to 191 elderly aged 65-74 y and 177 aged 75 y and older who reported their diet to be "as usual." In univariate analyses, BMI < 22, better health status, use of fewer than four medications and good reported appetite were significantly related to higher ER. No difference was shown in ER by gender, level of education, and family status. Weight loss superior 5 kg was associated with low ER (p = 0.049). In a linear regression model, low ER (indicating "underreporting") was significantly associated with higher activity level and use of over four medications. Using a dichotomous approach, Low Energy Reporters (LER) used a higher number of medications, ate fewer food items per day and suffered from poorer appetite. CONCLUSIONS: In the elderly, ER < 1 may indicate underreporting in dietary intake, and indeed, is frequent among the obese. Nonetheless, among the elderly, ER < 1 may reflect truly low caloric intake. Our results suggest that, to some degree, health status variables are associated with decreased ER, supporting a true caloric deprivation state.

Evidence for a Finite-Temperature Insulator.

In superconductors the zero-resistance current-flow is protected from dissipation at finite temperatures (T) by virtue of the short-circuit condition maintained by the electrons that remain in the condensed state. The recently suggested finite-T insulator and the "superinsulating" phase are different because any residual mechanism of conduction will eventually become dominant as the finite-T insulator sets-in. If the residual conduction is small it may be possible to observe the transition to these intriguing states. We show that the conductivity of the high magnetic-field insulator terminating superconductivity in amorphous indium-oxide exhibits an abrupt drop, and seem to approach a zero conductance at T < 0.04 K. We discuss our results in the light of theories that lead to a finite-T insulator.

Parallel magnetic field induced transition in transport in the dilute two-dimensional hole system in GaAs

A magnetic field applied parallel to the two-dimensional hole system in the GaAs/AlGaAs heterostructure, which is metallic in the absence of an external magnetic field, can drive the system into insulating at a finite field through a well-defined transition. The value of resistivity at the transition is found to depend strongly on density.

Dietary intake and eating patterns of elderly people in Israel: who is at nutritional risk?

OBJECTIVE: To determine dietary intake and eating patterns of older persons in Israel and to identify factors associated with low intake. DESIGN: A cross-sectional study. SETTING: Community-dwelling participants living in the Beer-Sheva area were interviewed at home, using a 24 h food questionnaire with additional questions regarding health and eating habits. Dietary intake was compared between people aged 65-74 and 75 y and older. SUBJECTS: A total of 377 people over the age of 65 224 aged 65-74 and 153>75, were randomly selected from the Negev population. RESULTS: Dietary intake of energy, fat, carbohydrates, vitamins E, C and B(1) were significantly lower for people aged 75 and older compared with people aged 65-74. Low energy intake was associated with lower subjective health status for men (P<0.01), poor appetite (P<0.01) and more gastrointestinal problems (P<0.05) for women and lower snack consumption (P<0.01) for both genders. In a multivariate model, low energy intake was associated with low appetite and higher use of medication for both sexes and with frequency of eating alone and not consuming snacks for men. CONCLUSIONS: Dietary intake is lower among individuals older than 75 than in 65-74 y old. Risk factors for low intake include poor appetite and health status, gastrointestinal problems, and eating alone. Snacking enhanced dietary intake and should be encouraged in this group.

Changes in dietary intake account for seasonal changes in cardiovascular disease risk factors.

OBJECTIVES: (1) to compare dietary intake in summer and winter time; (2) to measure the change in body mass index (BMI), blood pressure and serum cholesterol between winter and summer; and (3) to determine the relationships between seasonal differences in dietary intake and BMI, blood pressure and serum cholesterol measurements. SUBJECTS AND METHODS: Ninety-four male industrial employees were screened twice in one year, in their work place, at winter and summer time. Workers were recruited from two factories and response rate was 95%. Health-related variables, including dietary intake, blood pressure and serum cholesterol were evaluated at each season and were compared. Correlation coefficients between seasonal differences in dietary intake and in BMI, blood pressure and serum cholesterol were calculated. RESULTS: From summer to winter the mean values of BMI increase from 26.1 kg/cm2 to 26.6 (P=0.038), systolic blood pressure from 119.6 to 121.6 (P=0.025), diastolic blood pressure from 75.2 to 77.2 mmHg (P=0.001), total cholesterol from 200.8 to 208.6 mg/dL (P=0.001), LDL cholesterol from 125.2 to 134.9 (P=0.001) and HDL cholesterol from 42.7 to 44.3 (P=0.0084). Triglycerides levels decrease from 174 to 145 in the winter (P=0.03). Mean dietary intake of fat increases from 99.1 to 106.0 (P=0.0016), saturated fat from 43.6 to 46.3 (P=0.0137), polyunsaturated fat from 25.1 to 28.3 (P=0.0002), cholesterol from 462.0 to 497.9 (P=0.0313), sodium from 5778.5 to 8208.2 (P=0.0035), zinc from 11.6 to 12.3 (P=0.0001), vitamin B1 from 1.4 to 1.5 (P=0.002), vitamin D from 4.3 to 4.9 (P=0.0323) and vitamin E from 11.2 to 12.7 (P=0.0073). Significant correlation was shown between the seasonal increase in saturated fat and the increase in BMI (r=0.37), total cholesterol (r=0.21) and LDL cholesterol (r=0.29). Seasonal change in dietary cholesterol intake was significantly and positively correlated with serum total cholesterol (r=0.24) and LDL cholesterol (r=0.24). Blood pressure was not associated with nutritional intake variables. CONCLUSIONS: Dietary intake in summer and winter is different as well as blood pressure, BMI and serum cholesterol. The seasonal increase in fat and cholesterol intake at winter time is associated with changes in BMI and serum cholesterol.

CEBQ: Composite Eating Behavior Questionnaire--development and performance.

Poor eating behavior is an important nutritional risk factor among community dwelling elders, and precedes overt malnutrition in the majority of cases. Several tools were developed to assess nutritional risk through evaluating eating behavior. All containing elements shown to be related to nutritional decline. Given the diversity of the geriatric population each tool may apply to specific subsets of the population but not to all. The ideal tool may be a questionnaire tailored for the study population based on a pool of methods and questions. We describe the development and use of such a composite tool, and compares its performance to other questionnaires. Our results show that in community dwelling elders nutrition risk assessments such as the NRI or eating behavior score were not predictive of nutritional status measured by dietary intake, weight change or BMI. Subjective appetite assessment was the most predictive question for nutritional decline. We describe the questionnaire and its development and offer general advice to its future implementations.

High prevalence and impact of subnormal serum vitamin B12 levels in Israeli elders admitted to a geriatric hospital.

BACKGROUND: The elderly are known to have higher rates of low and subnormal vitamin B12 levels than younger persons. Vitamin B12 deficiency has been extensively studied in the elderly, but primarily in outpatient settings. There is a paucity of data regarding the prevalence of low and low-normal B12 in frail, hospitalized, elderly patients, and its implications. Additionally, there is little information regarding vitamin B12 status in Israeli elders. OBJECTIVES: The objectives of the study were to estimate the prevalence of low and borderline vitamin B12 levels among frail, hospitalized, elderly patients, and their clinical implications. METHODS: We conducted a chart review, using a retrospective cohort design. The participants were 895 patients admitted to Harzfeld Medical Center in Gedera, Israel. Records were abstracted for vitamin B12 and Folic Acid levels, gastric disease, and outcomes including death, cognitive impairment and neurologic disease. RESULTS: Six hundred and forty patients were eligible for the study. In 15% of the patients, vitamin B12 level was in the low range (<150pmol/L) and in 25% in the low-normal range (150-250pmol/L). Gastric disease and antacid use were not associated with the vitamin B12 status. Mortality was higher in the high vitamin B12 group (p=0.02), perhaps reflecting a selection toward higher acuity in this group. Cerebrovascular disease was more common in patients with lower vitamin B12 levels (p=0.046). CONCLUSIONS: Forty percent of hospitalized elderly patients have low or borderline serum levels of vitamin B12, which may contribute to cerebrovascular disease and cognitive decline.

The effect of widowhood on weight change, dietary intake, and eating behavior in the elderly population.

OBJECTIVES: To assess the effect of recent widowhood on weight, dietary intake, and habits. METHODS: Participants included 58 recently widowed elderly subjects and 58 married subjects who were matched on age, sex, and race. Weight change from baseline and following widowhood, dietary intake, eating behavior, depression, and cognitive and physical functioning were assessed in a clinic interview. RESULTS: Mean weight loss and the prevalence of weight loss were significantly higher among widowed participants. They ate more meals alone, more commercial meals per week, and fewer snacks and homemade meals. They also enjoyed their eating less. A significant difference between cases and controls was evident after adjusting for all the variables. Higher cognitive functioning score, younger age, and better appetite were protective against weight loss. DISCUSSION: Widowed people were found to be at increased risk for weight loss. This may well be due to decreased appetite and enjoyment of their meals.