Uniaxial strain control of spin-polarization in multicomponent nematic order of BaFe2As2.

The iron-based high temperature superconductors exhibit a rich phase diagram reflecting a complex interplay between spin, lattice, and orbital degrees of freedom. The nematic state observed in these compounds epitomizes this complexity, by entangling a real-space anisotropy in the spin fluctuation spectrum with ferro-orbital order and an orthorhombic lattice distortion. A subtle and less-explored facet of the interplay between these degrees of freedom arises from the sizable spin-orbit coupling present in these systems, which translates anisotropies in real space into anisotropies in spin space. We present nuclear magnetic resonance studies, which reveal that the magnetic fluctuation spectrum in the paramagnetic phase of BaFe2As2 acquires an anisotropic response in spin-space upon application of a tetragonal symmetry-breaking strain field. Our results unveil an internal spin structure of the nematic order parameter, indicating that electronic nematic materials may offer a route to magneto-mechanical control.

Nuclear magnetic resonance probe head design for precision strain control.

We present the design and construction of an NMR probe to investigate single crystals under strain at cryogenic temperatures. The probe head incorporates a piezoelectric-based apparatus from Razorbill Instruments that enables both compressive and tensile strain tuning up to strain values on the order of 0.3% with a precision of 0.001%. 75As NMR in BaFe2As2 reveals large changes to the electric field gradient and indicates that the strain is homogeneous to within 16% over the volume of the NMR coil.

Prevalence and recognition of alcohol abuse in a primary care population.

PURPOSE: The purpose of this study was to assess the prevalence, physician recognition, and treatment of alcohol abuse among patients of 19 senior medical residents practicing in a hospital-based, primary care setting. PATIENTS AND METHODS: Interviews of 242 outpatients were conducted, and alcohol abuse and dependence, as defined by the Diagnostic and Statistical Manual of Mental Disorders, third edition (DSM-III), were determined using the Diagnostic Interview Schedule. RESULTS: Twenty percent of the patients studied had abused or were dependent on alcohol at some time in their lives and 5 percent reported abuse or dependence within the last year. Of the techniques studied, a short screening questionnaire (Short Michigan Alcohol Screening Test [SMAST]) was the most accurate way of identifying patients who abused alcohol, and physician assessments were more accurate than laboratory tests. Although the physicians were aware of serious alcohol problems among 77 percent of their patients who met DSM-III criteria for alcohol abuse or dependence in the previous year, they identified only 36 percent of their patients with less serious problems or past alcohol abuse. They had only discussed alcohol abuse with 67 percent of the patients they identified as alcohol abusers. CONCLUSION: We conclude that a short screening questionnaire (SMAST) is an accurate means of identifying alcohol abuse. Despite the recognition of serious alcohol problems by the physicians, the problem is not addressed routinely even among patients that are recognized as alcoholic.

Erythrocyte sedimentation rate. From folklore to facts.

The erythrocyte sedimentation rate is a simple, inexpensive laboratory test that clinicians have used for decision-making for over 50 years. Despite this fact, many criticize the test because of its lack of specificity and because the concept of erythrocyte sedimentation rate as a "sickness index" seems scientifically unsound. This review discusses the physical and chemical properties that govern red blood cell sedimentation, how sedimentation is measured, and the way in which the erythrocyte sedimentation rate has previously been used to assist in the diagnosis of infectious, inflammatory, or neoplastic disease. The clinical significance, sensitivity, specificity, and predictive value of a low or elevated erythrocyte sedimentation rate are also re-evaluated.