Towards an MHD Theory for the Standoff Distance of Earth's Bow Shock

A magnetohydrodynamic (MHD) theory is developed for the standoff distance a(s) of the bow shock and the thickness Delta(ms) of the magnetosheath, using the empirical Spreiter et al. relation Delta(ms) = kX and the MHD density ratio X across the shock. The theory includes as special cases the well-known gasdynamic theory and associated phenomenological MHD-like models for Delta(ms) and As. In general, however, MHD effects produce major differences from previous models, especially at low Alfev (Ma) and Sonic (Ms) Mach numbers. The magnetic field orientation Ma, Ms and the ratio of specific heats gamma are all important variables of the theory. In contrast, the fast mode Mach number need play no direct role. Three principle conclusions are reached. First the gasdynamic and phenomenological models miss important dependences of field orientation and Ms generally provide poor approximations to the MHD results. Second, changes in field orientation and Ms are predicted to cause factor of approximately 4 changes in Delta(ms) at low Ma. These effects should be important when predicting the shock's location or calculating gramma from observations. Third, using Spreiter et al.'s value for k in the MHD theory leads to maxima a(s) values at low Ma and nominal Ms that are much smaller than observations and MHD simulations require. Resolving this problem requires either the modified Spreiter-like relation and larger k found in recent MHD simulations and/or a breakdown in the Spreiter-like relation at very low Ma

Analytic MHD Theory for Earth's Bow Shock at Low Mach Numbers

A previous MHD theory for the density jump at the Earth's bow shock, which assumed the Alfven M(A) and sonic M(s) Mach numbers are both much greater than 1, is reanalyzed and generalized. It is shown that the MHD jump equation can be analytically solved much more directly using perturbation theory, with the ordering determined by M(A) and M(s), and that the first-order perturbation solution is identical to the solution found in the earlier theory. The second-order perturbation solution is calculated, whereas the earlier approach cannot be used to obtain it. The second-order terms generally are important over most of the range of M(A) and M(s) in the solar wind when the angle theta between the normal to the bow shock and magnetic field is not close to 0 deg or 180 deg (the solutions are symmetric about 90 deg). This new perturbation solution is generally accurate under most solar wind conditions at 1 AU, with the exception of low Mach numbers when theta is close to 90 deg. In this exceptional case the new solution does not improve on the first-order solutions obtained earlier, and the predicted density ratio can vary by 10-20% from the exact numerical MHD solutions. For theta approx. = 90 deg another perturbation solution is derived that predicts the density ratio much more accurately. This second solution is typically accurate for quasi-perpendicular conditions. Taken together, these two analytical solutions are generally accurate for the Earth's bow shock, except in the rare circumstance that M(A) is less than or = 2. MHD and gasdynamic simulations have produced empirical models in which the shock's standoff distance a(s) is linearly related to the density jump ratio X at the subsolar point. Using an empirical relationship between a(s) and X obtained from MHD simulations, a(s) values predicted using the MHD solutions for X are compared with the predictions of phenomenological models commonly used for modeling observational data, and with the predictions of a modified phenomenological model proposed recently. The similarities and differences between these results are illustrated using plots of X and a(s) predicted for the Earth's bow shock. The plots show that the new analytic solutions agree very well with the exact numerical MHD solutions and that these MHD solutions should replace the corresponding phenomenological relations in comparisons with data. Furthermore, significant differences exist between the standoff distances predicted at low M(A) using the MHD models versus those predicted by the new modified phenomenological model. These differences should be amenable to observational testing

Relationships between pupils’ self-perceptions, views of primary school and their development in Year 5

The Effective Pre-school and Primary Education Project 3-11 (EPPE 3-11) is a largescale longitudinal study of the impact of pre-school and primary school on children’s developmental outcomes, both cognitive and social/behavioural. The study has been following children from the start of pre-school (at age 3 years plus) through to the end of primary school. Previous reports have focused on the educational and social/behavioural outcomes of the EPPE 3-11 sample at the end of Year 5 (age 10) and progress from the end of Year 1 (age 6) to the end of Year 5 (age 10) in primary school (Sammons et al., 2007a; 2007b). The research also explored the predictive power of a wide variety of child, parent, and family characteristics on attainment and development, including the Early years home learning environment (HLE) during the years of preschool and aspects of the later HLE during Key stage 1 of primary school (Sammons et al., 2002; 2003; Sylva et al., 2004). This research builds on earlier reports (Sammons et al., 2007a; 2007b) by investigating relationships between children’s outcomes in Year 5 and aspects of pupils’ selfperceptions and their views of primary school, measured in Year 5 (age 10) and in Year 2 (age 7) of primary school, controlling for background characteristics. These measures have been derived from a self-report instrument completed by EPPE 3-11 children. The analyses explored associations between children’s progress and development over time and their self-perceptions and views of primary school

Pupils' self-perceptions and views of primary school in year 5

The Effective Pre-School and Primary Education 3-11 (EPPE 3-11) project investigates the impact of preschool, primary school and family on a range of outcomes for a national sample of approximately 2,800 children in England between the ages of 3 and 11 years. This Research Brief presents findings on pupils’ Self-perceptions (‘Enjoyment of school’, ‘Anxiety and Isolation’, ‘Academic self-image’ and ‘Behavioural self-image’) and their views of different features of primary school (‘Teachers’ support for pupils’ learning’, ‘Headteacher qualities’ and ‘Positive social environment’) in Year 5. The analyses involved two steps: first, differences in pupils’ Self-perceptions and Views of primary school measured at Year 5 were explored, in relation to child, family and Home Learning Environment (HLE) characteristics. Second, the relationships between pupils’ Self-perceptions and their Views of primary school and educational outcomes and progress, both cognitive (Reading and Mathematics) and social/behavioural (‘Self-regulation’, ‘Hyperactivity’, ‘Pro-social’ and ‘Anti-social’ behaviour) were investigated. The analyses also explored pupils’ Self-perceptions measured at a younger age (Year 2) and how they relate to children’s later cognitive and social/behavioural outcomes in Year 5 and progress from Year 1 to Year 5

New diagnostic and imaging technologies in dermatology

Introduction Diagnosis of dermatological disorders is primarily based on clinical examination in combination with histopathology. However, clinical findings alone may not be sufficient for accurate diagnosis and cutaneous biopsies are being associated with morbidity. Objective The objective of this article is to review the newer technologies along with their applications, limitation and future prospectus. Methodology Comprehensive literature search was performed using electronic online databases “PubMed” and “Google Scholar”. Articles published in English language were considered for the review. Results In order to improve and/or widen the armamentarium in dermatologic disease diagnosis and therapy, newer emerging technologies are being made available which aid in diagnosis and management. New emerging technologies include confocal microscopy, digital photographic imaging, optical coherence tomography, high frequency ultrasonography, and artificial intelligence. There have been advancements in the dermoscopes. Conclusion Significant progress is seen in the diagnostic methods and imaging technologies in dermatology, each having its advantages and limitations. Artificial intelligence/machine-based learning software may have a great scope to influence the dermatological practice

Treatment of axillary hyperhidrosis

Background Axillary hyperhidrosis characterized by excessive sweating in the axillary regions is a frustrating chronic autonomic disorder leading to social embarrassment, impaired quality of life and usually associated with palmoplantar hyperhidrosis. Identifying the condition and its cause is central to the management. Aim The aim of this article is to discuss treatment options for axillary hyperhidrosis. Methods Comprehensive literature search using PubMed and Google Scholar was performed to review relevant published articles related to diagnosis and treatment of axillary hyperhidrosis. Results Treatment modalities for axillary hyperhydrosis vary from topical and systemic agents to injectables, newer devices and surgical measures. None except for physical measures using devices or surgery, which destroys the sweat glands to remove them, is possibly permanent and most are associated with attendant side effects. Conclusion Several treatments including medical and surgical option are available for the treatment of axillary hyperhydrosis. Patient education is important component of its management. Individualized approach of management is necessary for optimal outcome of treatment

The Rap1 Guanine Nucleotide Exchange Factor C3G Is Required for Preservation of Larval Muscle Integrity in Drosophila melanogaster

C3G is a guanine nucleotide exchange factor (GEF) and modulator of small G-protein activity, which primarily acts on members of the Rap GTPase subfamily. Via promotion of the active GTP bound conformation of target GTPases, C3G has been implicated in the regulation of multiple cellular and developmental events including proliferation, differentiation and apoptosis. The Drosophila C3G orthologue exhibits a domain organization similar to that of vertebrate C3G. Through deletion of the C3G locus, we have observed that loss of C3G causes semi-lethality, and that escaping adult flies are characterized by a reduction in lifespan and general fitness. In situ hybridization reveals C3G expression in the developing embryonic somatic and visceral muscles, and indeed analysis of C3G mutants suggests essential functions of C3G for normal body wall muscle development during larval stages. C3G mutants display abnormal muscle morphology and attachment, as well as failure to properly localize βPS integrins to muscle attachment sites. Moreover, we show that C3G stimulates guanine nucleotide exchange on Drosophila Rap GTPases in vitro. Taken together, we conclude that Drosophila C3G is a Rap1-specific GEF with important functions in maintaining muscle integrity during larval stages

Interaction of Dendritic Cells with Skin Endothelium: A New Perspective on Immunosurveillance

The goal of this study was to determine the mechanisms by which dendritic cells (DCs) in blood could interact with endothelium, a prerequisite to extravasation into tissues. Our results indicate that DCs express both HECA-452–reactive and nonreactive isoforms of P-selectin glycoprotein ligand 1 (PSGL-1) and can tether and roll efficiently on E- and P-selectin under flow conditions in vitro. Freshly isolated blood DCs were further observed to roll continuously along noninflamed murine dermal endothelium in vivo. This interaction is strictly dependent on endothelial selectins, as shown by experiments with blocking antibodies and with E- and P-selectin–deficient mice. We hypothesize that DCs in blood are constitutively poised at the interface of blood and skin, ready to extravasate upon induction of inflammation, and we showed that cutaneous inflammation results in a rapid recruitment of DCs from the blood to tissues. We propose that this is an important and previously unappreciated element of immunosurveillance

Efficacy of botulinum toxin in masseter muscle hypertrophy for lower face contouring

Background Masseter muscle hypertrophy (MMH) usually presents with cosmetic concerns as it may lead to widening of the lower face. Apart from the traditional surgical approaches, botulinum toxin type A (BTA) injection is a non-invasive treatment option available. There are no standard guidelines for this procedure. Objectives To study the efficacy of botulinumtoxin A in MMH for lower face contouring. Methodology The Cochrane Library, PubMed/MEDLINE, Google-scholar, Science-Direct database, and ResearchGate from inception until September 2021 were searched using the keywords “botulinumtoxin type A,” “masseter muscle hypertrophy,” “lower face contouring,” and “masseter botox.” All available retrospective and prospective studies, case-series, case-reports, and expert reviews were included with an emphasis on efficacy of BTA in MMH and units injected into the muscle, points of placement, adverse events, and the duration of its effect. Reference lists of the resultant articles, as well as relevant reviews, were also searched. Result 40 articles were shortlisted for the review, of which 14 studies with sample-size ≥10 in accordance with the study requirements were summarized in a tabular form for analysis and easy comparison and reference. Conclusion BTA injection is a non-invasive, safe, and effective treatment for MMH. The optimum number of BTA units could not be ascertained due to wide variability in the studies as well as ethnicity of patients and extent or some measurement of MMH. The points of placement of injection should be well within the boundaries of the masseter muscle. The maximum effect of BTA after a single injection session is usually seen in ~3 months, and the duration may last for 6–12 months. Multiple injection sessions may be required to maintain a long-term effect. Injection technique and total number of injection units of neuromodulator must be individualized for each patient