Self-Organized Criticality Effect on Stability: Magneto-Thermal Oscillations in a Granular YBCO Superconductor

We show that the self-organized criticality of the Bean's state in each of the grains of a granular superconductor results in magneto-thermal oscillations preceding a series of subsequent flux jumps. We find that the frequency of these oscillations is proportional to the external magnetic field sweep rate and is inversely proportional to the square root of the heat capacity. We demonstrate experimentally and theoretically the universality of this dependence that is mainly influenced by the granularity of the superconductor.Comment: submitted to Physical Review Letters, 4 pages, RevTeX, 4 figures available as uufile

A Vision for the Systematic Monitoring and Improvement of the Quality of Electronic Health Data

In parallel with the implementation of information and communications systems, health care organizations are beginning to amass large-scale repositories of clinical and administrative data. Many nations seek to leverage so-called Big Data repositories to support improvements in health outcomes, drug safety, health surveillance, and care delivery processes. An unsupported assumption is that electronic health care data are of sufficient quality to enable the varied use cases envisioned by health ministries. The reality is that many electronic health data sources are of suboptimal quality and unfit for particular uses. To more systematically define, characterize and improve electronic health data quality, we propose a novel framework for health data stewardship. The framework is adapted from prior data quality research outside of health, but it has been reshaped to apply a systems approach to data quality with an emphasis on health outcomes. The proposed framework is a beginning, not an end. We invite the biomedical informatics community to use and adapt the framework to improve health data quality and outcomes for populations in nations around the world

Measuring Population Health Using Electronic Health Records: Exploring Biases and Representativeness in a Community Health Information Exchange

Assessment is a core function of public health. Comprehensive clinical data may enhance community health assessment by providing up-to-date, representative data for use in public health programs and policies, especially when combined with community-level data relevant to social determinants. In this study we examine routinely collected and geospatially-enhanced EHR data to assess population health at various levels of geographic granularity available from a regional health information exchange. We present preliminary findings and discuss important biases in EHR data. Future work is needed to develop methods for correcting for those biases to support routine epidemiology work of public health

Deletion of the S3–S4 Linker in theShaker Potassium Channel Reveals Two Quenching Groups near the outside of S4

When attached outside the voltage-sensing S4 segment of the Shaker potassium channel, the fluorescent probe tetramethylrhodamine (TMRM) undergoes voltage-dependent fluorescence changes (ΔF) due to differential interaction with a pH-titratable external protein-lined vestibule (Cha, A., and F. Bezanilla. 1998. J. Gen. Physiol. 112:391–408.). We attached TMRM at the same sites [corresponding to M356C and A359C in the wild-type (wt) channel] in a deletion mutant of Shaker where all but the five amino acids closest to S4 had been removed from the S3–S4 linker. In the deletion mutant, the maximal ΔF/F seen was diminished 10-fold, and the ΔF at M356C became pH independent, suggesting that the protein-lined vestibule is made up in large part by the S3–S4 linker. The residual ΔF showed that the probe still interacted with two putative quenching groups near the S4 segment. One group was detected by M356C-TMRM (located outside of S3 in the deletion mutant) and reported on deactivation gating charge movement when applying hyperpolarizing voltage steps from a holding potential of 0 mV. During activating voltage steps from a holding potential of −90 mV, the fluorescence lagged considerably behind the movement of gating charge over a range of potentials. Another putative quenching group was seen by probes attached closer to the S4 and caused a ΔF at extreme hyperpolarizations (more negative than −90 mV) only. A signal from the interaction with this group in the wt S3–S4 linker channel (at L361C) correlated with gating charge moving in the hyperpolarized part of the Q-V curve. Probe attached at A359C in the deletion mutant and at L361C in wt channel showed a biphasic ΔF as the probe oscillated between the two groups, revealing that there is a transient state of the voltage sensor in between, where the probe has maximal fluorescence. We conclude that the voltage sensor undergoes two distinct conformational changes as seen from probes attached outside the S4 segment

Field induced evolution of regular and random 2D domain structures and shape of isolated domains in LiNbO₃ and LiTaO₃

The shapes of isolated domains produced by application of the uniform external electric field in different experimental conditions were investigated experimentally in single crystalline lithium niobate LiNbO3 and lithium tantalate LiTaO3. The study of the domain kinetics by computer simulation and experimentally by polarization reversal of the model structure using two-dimensional regular electrode pattern confirms applicability of the kinetic approach to explanation of the experimentally observed evolution of the domain shape and geometry of the domain structure. It has been shown that the fast domain walls strictly oriented along X directions appear after domain merging

Altruism and Informal Care for Dementia

Informal care is an important source of care for persons with dementia. The primary objective of this study is to explore the factors that affect the choice to provide informal care and test if altruistic attitudes change the mix of formal and informal care given to patients with dementia. Using the Aging Demographic and Memory Study dataset, we analyze how patient and caregiver characteristics affect the use of informal and formal healthcare services by dementia patients, focusing on the role of altruism. Assuming that the total care provided is an unobserved mix of informal and formal care, we use a latent class model to test if direct altruism increases the probability that informal care is included in the care plan. Greater patient need, as measured by limitations in the number of activities of daily living, and having three or more comorbid conditions decreased the probability of having only informal care, while needing supervision increased the probability of having only informal care. The direct altruism has a positive and significant marginal effect on increasing the probability of providing only informal care and decreasing the probability of being in the mix category of informal and formal category. Our model suggests that altruism in the form of caregivers’ pleasure from providing care increases the amount of informal care used. Although not socially inefficient, it does raise the cost of care as part of the cost is “spent” on caregiver’s pleasure. We find empirical evidence in support of this theoretical implication

Multihospital Infection Prevention Collaborative: Informatics Challenges and Strategies to Prevent MRSA

We formed a collaborative to spread effective MRSA prevention strategies. We conducted a two-phase, multisite, quasi-experimental study of seven hospital systems (11 hospitals) in IN, MT, ME and Ontario, Canada over six years. Patients with prior MRSA were identified at admission using regional health information exchange data. We developed a system to return an alert message indicating a prior history of MRSA, directed to infection preventionists and admissions. Alerts indicated the prior anatomic site, and the originating institution. The combined approach of training and coaching, implementation of MRSA registries, notifying hospitals on admission of previously infected or colonized patients, and change strategies was effective in reducing MRSA infections over 80%. Further research and development of electronic surveillance tools is needed to better integrate the varied data source and support preventing MRSA infections. Our study supports the importance of hospitals collaborating to share data and implement effective strategies to prevent MRSA

Pelvic inflammatory disease during the post-partum year.

OBJECTIVE: To investigate the occurrence of, and risk factors for, pelvic inflammatory disease (PID) occurring during the post-partum year. METHODS: Demographic and clinical data for women who delivered a term infant with 5-minute Apgar score > or = 8 from 1992 through 1999 at a large urban hospital were extracted from an electronic medical record system. RESULTS: During the study period, 15 206 deliveries occurred among 12 549 women. PID was diagnosed during the post-partum year of 148 (1.0%) deliveries. In univariate analysis, young age, black race, and both pre-delivery history and post-partum diagnosis of chlamydial and gonococcal infection were associated with PID. In multivariate analysis, only young age and a positive test for gonorrhea before delivery or post-partum were independent predictors of PID. CONCLUSIONS: Pelvic inflammatory disease was diagnosed during the post-partum year in 1% of women studied. Young maternal age was an important demographic risk factor. Further investigation of post-partum STD acquisition and progression to PID is needed to determine whether women are at increased risk following delivery

Area-level incarceration and STI risk among a cohort of justice-involved adolescents and adults

Background: Living in areas of high incarceration is associated with increased risk of STI; however, STI risk with respect to both this area-level exposure and an individual’s involvement with the justice system is not known. Objective: Among individuals before and after arrest or incarceration, assess the association between area-level incarceration rates and risk of chlamydia, gonorrhea, or syphilis. Methods: Retrospective cohort study of individuals living in Marion County (Indianapolis), Indiana who were arrested or in jail, prison, juvenile detention, or juvenile prison between 2005-2008 (N=97,765). Area-level incarceration exposure was defined by the proportion of person-days incarcerated among the total population*365 within a census block group. A 1-year period was assessed before and after a randomly-selected arrest/incarceration per person. Multivariable logistic regression, controlling for age, race, STI history, and year, was performed to assess chlamydia, gonorrhea, or syphilis risk by quartile area-level incarceration exposure, adjusting for individual clustering and stratifying by gender. Results: Area-level incarceration was associated with increased odds of each STI, with a dose response relationship particularly among those with an arrest or jail stay. Women with a history of arrest or jail/prison stay and living in high incarceration areas had higher odds of STI, compared to men with comparable incarceration history and living in similar areas