Anthropogenic Space Weather

Anthropogenic effects on the space environment started in the late 19th century and reached their peak in the 1960s when high-altitude nuclear explosions were carried out by the USA and the Soviet Union. These explosions created artificial radiation belts near Earth that resulted in major damages to several satellites. Another, unexpected impact of the high-altitude nuclear tests was the electromagnetic pulse (EMP) that can have devastating effects over a large geographic area (as large as the continental United States). Other anthropogenic impacts on the space environment include chemical release ex- periments, high-frequency wave heating of the ionosphere and the interaction of VLF waves with the radiation belts. This paper reviews the fundamental physical process behind these phenomena and discusses the observations of their impacts.Comment: 71 pages, 35 figure

Scaling anomaly in cosmic string background

We show that the classical scale symmetry of a particle moving in cosmic string background is broken upon inequivalent quantization of the classical system, leading to anomaly. The consequence of this anomaly is the formation of single bound state in the coupling interval \gamma\in(-1,1). The inequivalent quantization is characterized by a 1-parameter family of self-adjoint extension parameter \omega. It has been conjectured that the formation of loosely bound state in cosmic string background may lead to the so called anomalous scattering cross section for the particles, which is usually seen in molecular physics.Comment: 4 pages,1 figur

Intestinal Sugar Absorption is Regulated by Phosphorylation and Turnover of Protein Kinase C ߉I Mediated by Phosphatidylinositol 3-Kinase- and Mammalian Target of Rapamycin-dependent Pathways

Stimulation of intestinal fructose absorption by phorbol 12-myristate 13-acetate (PMA) results from rapid insertion of GLUT2 into the brush-border membrane and correlates with protein kinase C (PKC) {beta}II activation. We have therefore investigated the role of phosphatidylinositol 3 (PI3)-kinase and mammalian target of rapamycin in the regulation of fructose absorption by PKC {beta}II phosphorylation. In isolated jejunal loops, stimulation of fructose absorption by PMA was inhibited by preperfusion with wortmannin or rapamycin, which blocked GLUT2 activation and insertion into the brush-border membrane. Antibodies to the last 18 and last 10 residues of the C-terminal region of PKC {beta}II recognized several species differentially in Western blots. Extensive cleavage of native enzyme (80/78 kDa) to a catalytic domain product of 49 kDa occurred. PMA and sugars provoked turnover and degradation of PKC {beta}II by dephosphorylation to a 42-kDa species, which was converted to polyubiquitylated species detected at 180 and 250+ kDa. PMA increased the level of the PKC {beta}II 49-kDa species, which correlates with the GLUT2 level; wortmannin and rapamycin blocked these effects of PMA. Rapamycin and wortmannin inhibited PKC {beta}II turnover. PI3-kinase, PDK-1, and protein kinase B were present in the brush-border membrane, where their levels were increased by PMA and blocked by the inhibitors. We conclude that GLUT2-mediated fructose absorption is regulated through PI3-kinase and mammalian target of rapamycin-dependent pathways, which control phosphorylation of PKC {beta}II and its substrate-induced turnover and ubiquitin-dependent degradation. These findings suggest possible mechanisms for short term control of intestinal sugar absorption by insulin and amino acids

Patients’ perspectives on systemic sclerosis-related Raynaud's phenomenon in the feet: A qualitative study from the OMERACT Foot and Ankle Working Group

Objective To explore, from patients’ perspectives, the symptoms and impact of Raynaud's phenomenon (RP) on the feet of patients with systemic sclerosis (SSc-RP), and to identify which foot-related domains are important to patients. Methods Forty participants (34 women) with SSc-RP took part in one of six focus groups held in the United Kingdom or United States. Participants were purposively sampled to ensure diversity in disease type, duration, and ethnicity. The topic guide included questions on RP impact, self-management, and treatment expectations. Qualitative content analysis was employed to identify key concepts in the data relating to foot-specific symptoms and their impact. Themes were organized by corresponding domains of potential importance. Results Twenty-eight participants (70 %) reported experiencing RP in their feet. Five themes were identified corresponding to domains of potential importance: temperature changes, pain, cramping and stiffness, numbness, and color changes. These issues negatively affected participants’ lives, impairing walking, driving, and socializing, and causing issues with footwear and hosiery. Conclusions This large qualitative study exploring the experiences of patients with SSc-RP in the feet identified several key domains of high importance to patients. SSc-RP is common in the feet, presents in several patterns, and impacts multiple aspects of patients’ lives. These findings indicate where future foot-specific interventions for RP could be targeted. Findings from this study improve understanding of what domains are important to patients with SSc-RP affecting the feet and will contribute to the development of a core outcome set for foot and ankle disorders in rheumatic and musculoskeletal diseases

Whistler waves with angular momentum in space and laboratory plasmas and their counterparts in free space

Electromagnetic waves with helical phase surfaces arise in different fields of physics such as space plasmas, laboratory plasmas, solid-state physics, atomic, molecular and optical sciences. Their common features are the wave orbital angular momentum associated with the circular wave propagation around the axis of wave propagation. In plasmas these waves are called helicons. When particles or waves change the field momentum they experience a pressure and a torque which can lead to useful applications. In plasmas electrons can damp or excite rotating whistlers, depending on the electron distribution function in velocity space. A magnetized plasma is an anisotropic medium in which electromagnetic waves propagate differently than in space. Phase and group velocities are different such that wave focusing and wave reflections are different from those in free space. Electrons experience Doppler shifts and cyclotron resonance which creates wave damping and growth. All media exhibit nonlinear effects which do not occur in free space. Common and different features of vortex waves in different fields will be reviewed. However, a comprehensive review of this vast field is not possible and further readings are referred to the cited literature