3,478 research outputs found

    Observations of a barotropic planetary wave in the western North Atlantic

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    SOFAR float observations from 1300 m depth are used to describe a major feature of the large-scale, subthermocline velocity field observed in the western North Atlantic (31 N, 70W), during the 1978 POLYMODE Local Dynamics Experiment (LDE). The two-month-long intensive phase of the LDE was dominated by a highly polarized, oscillatory flow which had many of the characteristics of a barotropic planetary wave...

    Decoherence due to XPM-assisted Raman amplification for polarization or wavelength offset pulses in all-normal dispersion supercontinuum generation

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    We report the importance of cross-phase modulation (XPM) on the coherence of a low-energy probe pulse co-propagating with a high-energy pump pulse that generates incoherent supercontinuum in all-normal dispersion (ANDi) fiber due to Raman amplification of quantum noise. By investigating numerous fiber and pulse parameters, we show consistently that for weak probe pulses, the XPM from the pump is the dominant influence on the degradation of the probe coherence. We show that the faster decoherence at the pump leading edge means that the probe coherence is reduced more significantly when the probe has a higher group velocity, i.e., when an orthogonally polarized probe is aligned to the fast (lower refractive index) axis of the fiber or when a co-polarized probe has a longer central wavelength. Simulations show that this effect occurs for both polarization-maintaining (PM) and non-PM ANDi fibers and can result in a probe decoherence rate that is higher than that of the pump. These previously unreported results extend our earlier scalar simulations showing incoherent supercontinuum within a single pulse

    A comparison of registration errors with imageless computer navigation during MIS total knee arthroplasty versus standard incision total knee arthroplasty: A cadaveric study

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    © 2015 The Authors. Optimal component alignment in total knee arthroplasty has been associated with better functional outcome as well as improved implant longevity. The ability to align components optimally during minimally invasive (MIS) total knee replacement (TKR) has been a cause of concern. Computer navigation is a useful aid in achieving the desired alignment although it is limited by the error during the manual registration of landmarks. Our study aims to compare the registration process error between a standard and a MIS surgical approach. We hypothesized that performing the registration error via an MIS approach would increase the registration process error. Five fresh frozen lower limbs were routinely prepared and draped. The registration process was performed through an MIS approach. This was then extended to the standard approach and the registration was performed again. Two surgeons performed the registration process five times with each approach. Performing the registration process through the MIS approach was not associated with higher error compared to the standard approach in the alignment parameters of interest. This rejects our hypothesis. Image-free navigated MIS TKR does not appear to carry higher risk of component malalignment due to the registration process error. Navigation can be used during MIS TKR to improve alignment without reduced accuracy due to the approac

    The Relationship between Marital Status and Psychological Resilience in Chronic Pain

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    We examined the relationship between marital status and a 2-stage model of pain-related effect, consisting of pain unpleasantness and suffering. We studied 1914 chronic pain patients using multivariate analysis of covariance (MANCOVA) to clarify whether marital status was a determinant factor in the emotional or ideational suffering associated with chronic pain after controlling for pain sensation intensity, age, and ethnicity. Marital status was unrelated to immediate unpleasantness (). We found a strong association with emotional suffering () but not with negative illness beliefs (). Interestingly, widowed subjects experienced significantly less frustration, fear, and anger than all other groups (married, divorced, separated, or single). A final MANCOVA including sex as a covariate revealed that the emotional response to pain was the same for both widow and widower. Only those individuals whose spouse died experienced less emotional turmoil in the face of a condition threatening their lifestyle. These data suggest that after experiencing the death of a spouse, an individual may derive some “emotional inoculation” against future lifestyle threat

    Development of an Attribution of Racial/Ethnic Health Disparities Scale

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    The purpose of this study was to develop an Attribution of Racial/Ethnic Health Disparities (AREHD) scale. A convenience sample of undergraduate college students (n = 423) at four Midwestern universities was recruited to respond to the survey. A pilot test with undergraduate students (n = 23) found the survey had good acceptability and readability level (SMOG = 11th grade). Using exploratory factor analysis we found the two a priori subscales were confirmed: individual responsibility and social determinants. Internal reliabilities of the subscales were: individual responsibility (alpha = 0.87) and social determinants (alpha = 0.90). Test–retest stability reliabilities were: individual responsibility (r = 0.72) and social determinants (r = 0.69). The AREHD subscales are satisfactory for assessing college student’s AREHD

    A Pilot Study on the Effects of Exercise on Depression Symptoms Using Levels of Neurotransmitters and EEG as Markers

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    Context: The prescribing of exercise by physicians has become a popular practice, yet the effectiveness of exercise on symptoms of depression is difficult to determine due to a lack of randomized controlled trials with clinical populations. Reports also indicate that only a small percentage of physicians advise their patients regarding exercise and confusion still exists as to how much and what types are best. Aims: To understand the mechanisms that make exercise a viable treatment in depression. Settings and Design: This study employed a six‑week, two group, single‑level trial, pre‑ and posttest design using self‑report of symptoms, blood levels of serotonin, dopamine, epinephrine, and norepinephrine, and frontal slow wave EEG activity as markers. This study was registered with clinicaltrials.gov. ID# NCT02023281. Subjects and Methods: Eleven participants with a diagnosis of depression between the ages of 18 and 65 were enrolled from March 2013 through May 2013. Baseline and post‑intervention measures consisted of the Beck Depression Inventory‑II, blood serum levels of serotonin, catecholamines (epinephrine, norepinephrine, and dopamine), and mean alpha frequency. Statistical Analysis Used: A series of independent t‑tests for each dependent variable was conducted. Results: Independent t‑tests reveal significant between‑group differences in depression scores (P = 0.005, d = 2.23); F7 activity (P = 0.012, d = 1.92); and F8 activity (P = 0.04, d = 1.52). Conclusions: The results of this pilot study show that even mild to very moderate levels of exercise 2‑3 times per week consisting of alternating days of aerobic and strength resistance training can be effective in reducing symptoms of depression giving physicians concrete information for their patients on the prescription of exercise

    The effectiveness of automated digital health solutions at successfully managing obesity and obesity-associated disorders: A PICO-structured investigation

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    Most adults in the UK and USA are classified as overweight or obese. Recent studies suggest that the prevalence of obesity has further increased during the SARS-CoV-2 pandemic and associated lockdowns. Digital technologies may be effective at managing obesity and related comorbidities, a potential further justified by social isolation and distancing circumstances. This review of published literature employed a Patient-Intervention-Comparison-Outcome structured approach on the use of digital solutions to determine the effectiveness of their use in the management and treatment of obesity, hypertension, and type 2 diabetes and included commercially available, automated devices and applications that did not require intervention from a clinician. Our search covered studies published between January 2004 and February 2019, and 18 papers were included in the final analysis. The digital solutions reviewed were smartphone applications, wearable activity trackers, and ‘digital medicine offerings’ (DMO), including ingestible sensors and wearable patches. This study found that not all interventions were effective at encouraging the lifestyle changes required for the management of obesity. Smartphone applications requiring interaction from the patient appeared to be more effective at encouraging engagement with treatment interventions than more passive wearable activity trackers. Automated feedback from smartphone applications was effective at managing type 2 diabetes, while DMO were effective at reducing blood pressure. With the advancement of new technologies alongside a rapid increase in the prevalence of obesity and associated disorders, further studies comparing the various technologies available in larger sample populations for longer periods would help determine the most cost-effective preventive and therapeutic strategies
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