Electrolytic lesions within central complex neuropils of the cockroach brain affect negotiation of barriers

Animals must negotiate obstacles in their path in order to successfully function within natural environments. These actions require transitions from walking to other behaviors, many of which are more involved than simple reflexes. For these behaviors to be successful, insects must evaluate objects in their path and then use that information to change posture or re-direct leg movements. Some of this control may occur within a region of the brain known as the central complex (CC). We used discrete electrolytic lesions to examine the role of certain sub-regions of the CC in various obstacle negotiation behaviors. We found that cockroaches with lesions to the protocerebral bridge (PB) and ellipsoid body (EB) exhibit abnormalities in turning and dealing with shelf-like objects; whereas, individuals with lesions to the fan-shaped body (FB) and lateral accessory lobe (LAL), exhibit abnormalities of those behaviors as well as climbing over blocks and up walls to a horizontal plane. Abnormalities in block climbing include decreased success rate, changes in climbing strategy, and delayed response to the block. Increases in these abnormal behaviors were significant in individuals with lesions to the FB and LAL. Although turning abnormalities are present in individuals with lesions to the LAL, EB and the lateral region of the FB, there are some differences in how these deficits present. For instance, the turning deficits seen in individuals with lateral FB lesions only occurred when turning in the direction opposite to the side of the brain on which the lesion occurred. By contrast, individuals with lesions to the EB and LAL exhibited turning abnormalities in both directions. Lesions in the medial region of the FB did not result in directional turning deficits, but in abnormalities in block climbing

Numerical computation of an Evans function for travelling waves

We demonstrate a geometrically inspired technique for computing Evans functions for the linearised operators about travelling waves. Using the examples of the F-KPP equation and a Keller-Segel model of bacterial chemotaxis, we produce an Evans function which is computable through several orders of magnitude in the spectral parameter and show how such a function can naturally be extended into the continuous spectrum. In both examples, we use this function to numerically verify the absence of eigenvalues in a large region of the right half of the spectral plane. We also include a new proof of spectral stability in the appropriate weighted space of travelling waves of speed $c \geq 2 \sqrt{\delta}$ in the F-KPP equation.Comment: 37 pages, 11 figure

“If you can’t see a dilemma in this situation you should probably regard it as a warning”. A metasynthesis and theoretical modeling of general practitioners’ opioid prescription experiences in primary care.

Background: The prescribing of opioids has increased internationally in developed countries in recent decades within primary and secondary care.1 The majority of patients with chronic non-malignant pain (CNMP) are managed by their GP.2 Recent qualitative studies have examined the issue of opioid prescribing for chronic non-malignant pain (CNMP) from a GP viewpoint. Several factors have been reported to influence the prescribing of opioids for CNMP including aetiology of pain condition, co-morbidities, access to specialised care, history of drug abuse and professional scrutiny. We require a better understanding of problems GP’s face when making opioid prescribing decisions, interventions to provide better supports in the prescribing of opioids for CNMP. The aim of this study is to identify and synthesize the qualitative literature describing the factors influencing the nature and extent of opioid prescribing in CNMP in primary care. A theoretical model is then proposed which seeks to explain the relationship between factors influencing prescribing of opioids for CNMP by GPs. Methods: MEDLINE, Embase, PsychINFO, Cochrane Database, International Pharmaceutical Abstracts, Database of Abstracts of Reviews of Effects, CINAHL and Web of Science were systematically searched from January 1986- Feb 2018. Two reviewers independently screened titles and abstracts. Studies were excluded from the review if they were non-English language, theoretical or methodological articles, policy documents, conference abstracts or presentations, as where quotations were not clearly attributed to GPs participating in the study. The reviewers then independently assessed the full text of the articles using the Critical Appraisal Skills Programme (CASP) tool for qualitative research. The papers were coded by two researcher and these codes organised using Thematic Network Analysis. Basis themes were defined initially, organising themes were then developed followed by global themes which summarised the key theories emerging from the articles. Finally, a theoretical model was derived by the researchers using the global themes to explain the interplay between factors influencing opioid prescribing decisions. Results: From 7020 records, 18 full text papers were assessed, and 13 studies included in the synthesis; 9 were from USA, 3 from UK and 1 from Sweden. Seven organising themes were identified including trust and mistrust, the importance of aetiology, monitoring of prescription use, physical, psychological and societal harm, consultation variables, inadequate pain management, stigma and stereotypes and system barriers to effective and safe prescribing such as limited access to specialist care or support from allied healthcare professionals in primary care. Four global themes emerged;suspicion, risk, agreement and encompassing systems level factors. These global themes are inter-related and capture the complex decision-making processes underlying the opioid prescribing whereby the physician both consciously and subconsciously quantifies the risk-benefit relationship associated with initiating or continuing an opioid prescription. Conclusion: Prescribing of opioids for CNMP is influenced by a myriad of factors. Rather, than a simple risk-benefit view of the process, it is more useful to view this as a dynamic process in which unique considerations such as the morality of opioid use exert an effect. Recognising the inherent complexity of the process and the limitations of healthcare systems, guidelines directed at GPs should offer more nuanced recommendations on managing opioid prescribing consultations in primary care

Absence of the Rashba effect in undoped asymmetric quantum wells

To an electron moving in free space an electric field appears as a magnetic field which interacts with and can reorient the electron spin. In semiconductor quantum wells this spin-orbit interaction seems to offer the possibility of gate-voltage control in spintronic devices but, as the electrons are subject to both ion-core and macroscopic structural potentials, this over-simple picture has lead to intense debate. For example, an externally applied field acting on the envelope of the electron wavefunction determined by the macroscopic potential, underestimates the experimentally observed spin-orbit field by many orders of magnitude while the Ehrenfest theorem suggests that it should actually be zero. Here we challenge, both experimentally and theoretically, the widely held belief that any inversion asymmetry of the macroscopic potential, not only electric field, will produce a significant spin-orbit field for electrons. This conclusion has far-reaching consequences for the design of spintronic devices while illuminating important fundamental physics.Comment: 7 pages, 5 fig

A CASE STUDY ON THE EFFECTS OF THE UPPER ARM DEFINITION ON SHOULDER AND ELBOW KINEMATICS DURING THE BADMINTON SMASH

The aim of this case study was to identify the effect of the upper arm definition on shoulder and elbow kinematics during the badminton smash. A method was proposed that corrects the false external rotation when using the shoulder-elbow-wrist plane based on the carrying angle (ISB-2C) and compared to ISB recommendations for defining the upper arm (ISB-1 and ISB-2). Differences were found in shoulder and elbow kinematics, in particular angular velocities. Both magnitude and the time history of the angular velocity were affected. In particular, use of the medial and lateral epicondyles was unable to detect a reasonable signal for pronation/supination. ISB-2C reduces some of the problems associated with ISB-1 and ISB-2 e.g. soft-tissue artifact, proximity of medial and lateral epicondyles to the humeral longitudinal axis and false external rotation caused by the carrying angle

Polymeric IgA and immune complex concentrations in IgA-related renal disease

Polymeric IgA and immune complex concentrations in IgA-related renal disease. Polymeric IgA (PIgA) and immune complex concentrations in IgA-related renal disease were measured in cross sectional and longitudinal studies to establish the relationship between these parameters and both mucosal infection and renal dysfunction. These studies were performed in 50 patients with IgA nephropathy (IgAN), 17 patients with Henoch Schönlein purpura nephritis (HSPN), 11 control patients with IgA negative, diffuse mesangial proliferative glomerulonephritis (DMPGN) and 50 healthy controls. Total PIgA (PIgAT) and PIgA subclass concentrations were measured using a secretory component binding enzyme immunoassay and isotype specific immune complex concentrations were measured using conglutinin (K) binding immunoassays. In cross sectional studies patients with IgAN were found to have increased concentrations of PIgAT, PIgA1, K-IgA1 and K-IgA2 compared to controls. In the longitudinal studies controls and patients had significant increases in PIgAT and PIgA1 concentrations during infection. However, in patients with IgAN, the increases were greater, persisted for longer, and PIgA2 concentrations were also increased. K-IgA1 and K-IgA2 concentrations increased significantly during episodes of infection in IgAN patients in contrast to controls. Patients with HSPN had results similar to those of IgAN patients. No significant correlation was found between PIgA or K-IgA concentrations, and either serum creatinine concentrations or the degree of hematuria. The results indicate that patients with IgA-related renal disease have abnormal regulation of PIgA and immune complexed IgA, and that these abnormalities are exaggerated during mucosal infection

Approximate Flavor Symmetries in the Lepton Sector

Approximate flavor symmetries in the quark sector have been used as a handle on physics beyond the Standard Model. Due to the great interest in neutrino masses and mixings and the wealth of existing and proposed neutrino experiments it is important to extend this analysis to the leptonic sector. We show that in the see-saw mechanism, the neutrino masses and mixing angles do not depend on the details of the right-handed neutrino flavor symmetry breaking, and are related by a simple formula. We propose several ans\"{a}tze which relate different flavor symmetry breaking parameters and find that the MSW solution to the solar neutrino problem is always easily fit. Further, the $\nu_\mu - \nu_\tau$ oscillation is unlikely to solve the atmospheric neutrino problem and, if we fix the neutrino mass scale by the MSW solution, the neutrino masses are found to be too small to close the Universe.Comment: 12 pages (no figures), LBL-3459