Solar wind test of the de Broglie-Proca's massive photon with Cluster multi-spacecraft data

Our understanding of the universe at large and small scales relies largely on electromagnetic observations. As photons are the messengers, fundamental physics has a concern in testing their properties, including the absence of mass. We use Cluster four spacecraft data in the solar wind at 1 AU to estimate the mass upper limit for the photon. We look for deviations from Amp\`ere's law, through the curlometer technique for the computation of the magnetic field, and through the measurements of ion and electron velocities for the computation of the current. We show that the upper bound for $m_\gamma$ lies between $1.4 \times 10^{-49}$ and $3.4 \times 10^{-51}$ kg, and thereby discuss the currently accepted lower limits in the solar wind.Comment: The paper points out that actual photon mass upper limits (in the solar wind) are too optimistic and model based. We instead perform a much more experiment oriented measurement. This version matches that accepted by Astroparticle Physic

Thin electron-scale layers at the magnetopause

We use data from the four Cluster satellites to examine the microphysics of a thin electron-scale layer discovered on the magnetospheric side of the magnetopause. Here the ion and electron motions are decoupled in a layer about 20 km (a few electron scales) wide, including currents and strong electric fields. In this layer the electrons are E x B drifting with the ions as a background, and the region can be described by Hall MHD physics. A unique identification of the source of the thin layer is not possible, but our observations are consistent with recent simulations showing thin layers associated with the separatrix extending far away from a reconnection diffusion region

Electron Dynamics in the Diffusion Region of an Asymmetric Magnetic Reconnection

During a magnetopause crossing near the subsolar point Cluster observes the ion diffusion region of antiparallel magnetic reconnection. The reconnecting plasmas are asymmetric, differing in magnetic field strength, density, and temperature. Spatial changes in the electron distributions in the diffusion region are resolved and investigated in detail. Heating of magnetosheath electrons parallel to the magnetic field is observed. This heating is shown to be consistent with trapping of magnetosheath electrons by parallel electric fields

Cleft Candidate Genes and Their Products in Human Unilateral Cleft Lip Tissue

Cleft lip and palate are common congenital pathologies that affect the human population worldwide. The formation of cleft lip is associated with multiple genes and their coded proteins, which regulate the development of craniofacial region, but the exact role of these factors is not always clear. The use of morphological studies for evaluation of human cleft-affected tissue has been limited because of insufficiency of available pathological material. The aim of this study was to detect and compare the immunohistochemical expression of cleft candidate gene coded proteins (DLX4, MSX2, HOXB3, SHH, PAX7, SOX3, WNT3A, and FOXE1) in the non-syndromic unilateral cleft lip patient tissue and control group tissue. A semiquantitative counting method was used to evaluate the tissue in biotin-streptavidin-stained slides. Statistically significant differences between the patient and control groups were found for the number of immunoreactive structures for SHH (p = 0.019) and FOXE1 (p = 0.011) in the connective tissue and SOX3 (p = 0.012) in the epithelium. Multiple statistically significant very strong and strong correlations were found between the immunoreactives in cleft-affected tissue. These significant differences and various correlations indicate that multiple morphopathogenetic pathways are possibly involved in unilateral cleft lip pathogenesis. Therefore, we further discuss these possible interactions.publishersversionPeer reviewe

Compressional Pc5 type pulsations in the morningside plasma sheet

International audienceWe study compressional pulsations in Pc5 frequency range observed in the dawn-side at distances of about 10 RE , close to the magnetic equator. We use data obtained during two events of conjunctions between Equator-S and Geotail: 1000?1700 UT on 9 March 1998, and 0200?0600 UT on 25 April 1998. In both events, pulsations are observed after substorm activity. The pulsations are antisymmetric with respect to the equatorial plane (even mode), and move eastward with phase velocity close to plasma velocity. The pulsations tend to be pressure balanced. We also discuss possible generation mechanisms of the pulsations

SELF-REPORTED MUSCULOSKELETAL ACUTE AND OVERUSE INJURIES AMONG LATVIAN INFANTRY SOLDIERS

Musculoskeletal injury is the leading cause of disability among different military populations that results in socioeconomic burden and negatively affects military readiness. Study aim was to describe self-reported musculoskeletal injuries among Latvian infantry soldiers during one-year period. Survey-based cross-sectional study was carried out. Data was assessed using survey about injuries that occurred in one-year period during annual medical check-up. Musculoskeletal injuries were classified according to body regions as it is in Barell injury matrix and by injury type – acute or overuse. Study results showed in one-year injury incidence rate was 867.8 cases per 1000 person-years (95% CI 824.8 – 913.0) with total 197 musculoskeletal injuries reported among active duty infantry soldiers. Typical acute injuries were superficial contusion injuries (n=24), fractures (n=21), joint dislocations (n=21) and sprains (n=29). Typical overuse diagnoses were lower back pain (n=42), patellofemoral pain syndrome (n=11), medial tibial stress syndrome (n=9), plantar fasciitis (n=8). Present study showed high incidence of overuse back injuries and overuse and acute lower leg injuries. Mostly of reported injuries could be classified as preventable and should be reduced through injury reduction programmes.

Peak plantar pressure as a risk factor for lower extremity overuse injury among infantry soldiers

Publisher Copyright: © 2021 Sciendo. All rights reserved.The majority of reported injuries among military populations are injuries due to cumulative repetitive microtrauma — overuse injuries. Plantar pressure measurement is a simple tool to analyse lower limb biomechanics through the assessment of forces applied to the foot. This study aimed to determine the relation between peak plantar pressure and lower extremity overuse. Sixty-six active-duty infantry male soldiers, with mean age 29.7 years (range 22–40 years), and mean service time 5.2 years (range 1–15 years) participated. The highest peak plantar pressure (PPP) at the forefoot occurred at the hallux (cases: 50.82 n/cm2, SD = 38.84; control: 34.39 n/cm2, SD = 28.03) and 3rd metatarsal head (cases: 54.40 n/cm2, SD = 33.83; control: 49.16 n/cm2, SD = 28.87). The study demonstrated elevated PPP among cases. Statistically significant results were found at the hallux (c2(1) = 6.8; p = 0.01), medial heel (c2(1) = 5.18; p = 0.02) and lateral heel (c2(1) = 12.12; p < 0.01) regions. The results show that plantar pressure assessment could be used as a useful screening tool for early lower extremity overuse injury detection.Peer reviewe

Intermittent energy dissipation by turbulent reconnection

Magnetic reconnection—the process responsible for many explosive phenomena in both nature and laboratory—is efficient at dissipating magnetic energy into particle energy. To date, exactly how this dissipation happens remains unclear, owing to the scarcity of multipoint measurements of the “diffusion region” at the sub-ion scale. Here we report such a measurement by Cluster—four spacecraft with separation of 1/5 ion scale. We discover numerous current filaments and magnetic nulls inside the diffusion region of magnetic reconnection, with the strongest currents appearing at spiral nulls (O-lines) and the separatrices. Inside each current filament, kinetic-scale turbulence is significantly increased and the energy dissipation, E′ ⋅ j, is 100 times larger than the typical value. At the jet reversal point, where radial nulls (X-lines) are detected, the current, turbulence, and energy dissipations are surprisingly small. All these features clearly demonstrate that energy dissipation in magnetic reconnection occurs at O-lines but not X-lines

Relationship of footwear comfort, selected size, and lower leg overuse injuries among infantry soldiers

Funding Information: This research was financially supported by a Rīga Stradiņš University doctoral research grant. Funding Information: The authors would like to thank the soldiers who participated in the study and the Latvian National Army Logistic Command Military Medical Support Centre for the support. Publisher Copyright: © 2021, The Author(s).BACKGROUND: High rates of musculoskeletal injuries such as plantar fasciitis and stress fractures have been observed among physically active military personnel. During service time, infantry soldiers use issued boots daily that should fit well and provide comfort to prevent injuries and decrease lower extremity pain effectively. The association of military boot comfort with overuse injuries remains unclear. This study investigates the relationship between the chosen military boot size, perceived boot comfort and lower leg overuse injury. METHODS: During the cross-sectional study, 227 (males, n = 213; females, n = 14) active-duty infantry soldiers at a mean age of 29.5 years old, and with an average service time of 7.2 years were assessed for a history of overuse injury, footprint length, appropriate shoe size, and footwear comfort. Males with a history of overuse injury (n = 32) and non-injured age-matched controls (n = 34) were selected for detailed testing and establishing the possible relationship between footwear comfort and lower leg overuse injury. RESULTS: No relationship was found between footwear comfort and a history of lower leg overuse injury. N = 38 (57.6%) of study subjects were wearing an inappropriate shoe size daily. Inappropriate shoe size usage affected footwear comfort ratings significantly. CONCLUSIONS: Study results showed that improper boot size was significantly related to comfort ratings but was not associated with a history of lower leg overuse injury.publishersversionPeer reviewe