Ricci Collineations of the Bianchi Types I and III, and Kantowski-Sachs Spacetimes

Ricci collineations of the Bianchi types I and III, and Kantowski-Sachs space- times are classified according to their Ricci collineation vector (RCV) field of the form (i)-(iv) one component of $\xi^a (x^b)$ is nonzero, (v)-(x) two components of $\xi^a (x^b)$ are nonzero, and (xi)-(xiv) three components of $\xi^a (x^b)$ are nonzero. Their relation with isometries of the space-times is established. In case (v), when $det(R_{ab}) = 0$, some metrics are found under the time transformation, in which some of these metrics are known, and the other ones new. Finally, the family of contracted Ricci collineations (CRC) are presented.Comment: 21 Pages, LaTeX, no figures, accepted for publication in the International Journal of Modern Physics

In Vivo Neuromechanics: Decoding Causal Motor Neuron Behavior with Resulting Musculoskeletal Function.

Human motor function emerges from the interaction between the neuromuscular and the musculoskeletal systems. Despite the knowledge of the mechanisms underlying neural and mechanical functions, there is no relevant understanding of the neuro-mechanical interplay in the neuro-musculo-skeletal system. This currently represents the major challenge to the understanding of human movement. We address this challenge by proposing a paradigm for investigating spinal motor neuron contribution to skeletal joint mechanical function in the intact human in vivo. We employ multi-muscle spatial sampling and deconvolution of high-density fiber electrical activity to decode accurate α-motor neuron discharges across five lumbosacral segments in the human spinal cord. We use complete α-motor neuron discharge series to drive forward subject-specific models of the musculoskeletal system in open-loop with no corrective feedback. We perform validation tests where mechanical moments are estimated with no knowledge of reference data over unseen conditions. This enables accurate blinded estimation of ankle function purely from motor neuron information. Remarkably, this enables observing causal associations between spinal motor neuron activity and joint moment control. We provide a new class of neural data-driven musculoskeletal modeling formulations for bridging between movement neural and mechanical levels in vivo with implications for understanding motor physiology, pathology, and recovery

Drugs with anticholinergic side-effects in primary care

Background: Anticholinergic drugs in elderly people have been associated with some serious side.effects. Patients in Turkey tend to attend primary care centers to have prescriptions of the drugs they chronically use. However, very little are known about how frequent that these drugs are prescribed and their side-effects in Turkish population. We aimed to investigate the usage and side.effects of drugs with anticholinergic  properties in patients over 65 years of age attending to primary care centers.Materials and Methods: Five hundred and sixty.three subjects were interviewed with a questionnaire of 16 questions inquiring their medication and possible side.effects. Timed up and go test (TUGT) and standardized mini.mental test (SMMT) were also performed.Results: Medical records of 563 individuals were screened to detect  anticholinergic medication. Twenty.eight patients were using anticholinergic medication. Mean duration of anticholinergic medication usage was 3.17 years. Mean number of falls occurred in the previous year was 1.14 « 1.17. Mean SMMT score was 27.20 « 1.13. Mean TUGT scores mean was 12.4 « 1.25. Drowsiness in 18 patients (65%), dry mouth in 15 patients (53%), dry eyes in 15 patients (53%), constipation in 11 patients (39%), blurred vision in 11 patients (%39), urinary hesitancy in eight patients (28%), confusion in six patients (21%) were reported. We found that none of the subjects were evaluated in terms of fall risk or mental status by their  doctors before the prescription of drugs with anticholinergic effects.Conclusions: A suggested approach to improve drug safety was reported as to reduce the use of anticholinergic drugs when it is possible. Psychiatrists and family physicians should select less anticholinergic drugs for  medication and have to evaluate their patientsf fall risk and their cognitive status before prescribing drugs with anticholinergic side effects.Key words: Anticholinergic side effects, cognitive status, fall risk, primary car

Nanoscale addressing and manipulation of neutral atoms using electromagnetically induced transparency

We propose to integrate dark-state based localization techniques into a neutral atom quantum computing architecture and numerically investigate two specific schemes. The first scheme implements state-selective projective measurement by scattering photons from a specific qubit with very little cross talk on the other atoms in the ensemble. The second scheme performs a single-qubit phase gate on the target atom with an incoherent spontaneous emission probability as low as 0.01. Our numerical simulations in rubidium (Rb) atoms show that for both of these schemes a spatial resolution at the level of tens of nanometers using near-infrared light can be achieved with experimentally realistic parameters

Classification of Spherically Symmetric Static Spacetimes according to their Matter Collineations

The spherically symmetric static spacetimes are classified according to their matter collineations. These are studied when the energy-momentum tensor is degenerate and also when it is non-degenerate. We have found a case where the energy-momentum tensor is degenerate but the group of matter collineations is finite. For the non-degenerate case, we obtain either {\it four}, {\it five}, {\it six} or {\it ten} independent matter collineations in which four are isometries and the rest are proper. We conclude that the matter collineations coincide with the Ricci collineations but the constraint equations are different which on solving can provide physically interesting cosmological solutions.Comment: 15 pages, no figure, Late

Ricci Collineations of the Bianchi Type II, VIII, and IX Space-times

Ricci and contracted Ricci collineations of the Bianchi type II, VIII, and IX space-times, associated with the vector fields of the form (i) one component of $\xi^a(x^b)$ is different from zero and (ii) two components of $\xi^a(x^b)$ are different from zero, for $a,b=1,2,3,4$, are presented. In subcase (i.b), which is $\xi^a= (0,\xi^2(x^a),0,0)$, some known solutions are found, and in subcase (i.d), which is $\xi^a =(0,0,0,\xi^4(x^a))$, choosing $S(t)=const.\times R(t)$, the Bianchi type II, VIII, and IX space-times is reduced to the Robertson-Walker metric.Comment: 12 Pages, LaTeX, 1 Table, no figure