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

Continuous cerebroventricular administration of dopamine: A new treatment for severe dyskinesia in Parkinson’s disease?

In Parkinson’s disease (PD) depletion of dopamine in the nigro-striatal pathway is a main pathological hallmark that requires continuous and focal restoration. Current predominant treatment with intermittent oral administration of its precursor, Levodopa (l-dopa), remains the gold standard but pharmacological drawbacks trigger motor fluctuations and dyskinesia. Continuous intracerebroventricular (i.c.v.) administration of dopamine previously failed as a therapy because of an inability to resolve the accelerated dopamine oxidation and tachyphylaxia. We aim to overcome prior challenges by demonstrating treatment feasibility and efficacy of continuous i.c.v. of dopamine close to the striatum. Dopamine prepared either anaerobically (A-dopamine) or aerobically (O-dopamine) in the presence or absence of a conservator (sodium metabisulfite, SMBS) was assessed upon acute MPTP and chronic 6-OHDA lesioning and compared to peripheral l-dopa treatment. A-dopamine restored motor function and induced a dose dependent increase of nigro-striatal tyrosine hydroxylase positive neurons in mice after 7 days of MPTP insult that was not evident with either O-dopamine or l-dopa. In the 6-OHDA rat model, continuous circadian i.c.v. injection of A-dopamine over 30 days also improved motor activity without occurrence of tachyphylaxia. This safety profile was highly favorable as A-dopamine did not induce dyskinesia or behavioral sensitization as observed with peripheral l-dopa treatment. Indicative of a new therapeutic strategy for patients suffering from l-dopa related complications with dyskinesia, continuous i.c.v. of A-dopamine has greater efficacy in mediating motor impairment over a large therapeutic index without inducing dyskinesia and tachyphylaxia

Half-metallicity and Slater-Pauling behavior in the ferromagnetic Heusler alloys

Introductory chapter for the book "Halfmetallic Alloys - Fundamentals and Applications" to be published in the series Springer Lecture Notes on Physics, P. H. Dederichs and I. Galanakis (eds). It contains a review of the theoretical work on the half-metallic Heusler alloys.Comment: Introductory chapter for the book "Halfmetallic Alloys - Fundamentals and Applications" to be published in the series Springer Lecture Notes on Physics, P. H. Dederichs and I. Galanakis (eds

Effects of sleep deprivation on neural functioning: an integrative review

Sleep deprivation has a broad variety of effects on human performance and neural functioning that manifest themselves at different levels of description. On a macroscopic level, sleep deprivation mainly affects executive functions, especially in novel tasks. Macroscopic and mesoscopic effects of sleep deprivation on brain activity include reduced cortical responsiveness to incoming stimuli, reflecting reduced attention. On a microscopic level, sleep deprivation is associated with increased levels of adenosine, a neuromodulator that has a general inhibitory effect on neural activity. The inhibition of cholinergic nuclei appears particularly relevant, as the associated decrease in cortical acetylcholine seems to cause effects of sleep deprivation on macroscopic brain activity. In general, however, the relationships between the neural effects of sleep deprivation across observation scales are poorly understood and uncovering these relationships should be a primary target in future research

Space Telescope and Optical Reverberation Mapping Project. VII. Understanding the Ultraviolet Anomaly in NGC 5548 with X-Ray Spectroscopy

During the Space Telescope and Optical Reverberation Mapping Project observations of NGC 5548, the continuum and emission-line variability became decorrelated during the second half of the six-month-long observing campaign. Here we present Swift and Chandra X-ray spectra of NGC 5548 obtained as part of the campaign. The Swift spectra show that excess flux (relative to a power-law continuum) in the soft X-ray band appears before the start of the anomalous emission-line behavior, peaks during the period of the anomaly, and then declines. This is a model-independent result suggesting that the soft excess is related to the anomaly. We divide the Swift data into on- and off-anomaly spectra to characterize the soft excess via spectral fitting. The cause of the spectral differences is likely due to a change in the intrinsic spectrum rather than to variable obscuration or partial covering. The Chandra spectra have lower signal-to-noise ratios, but are consistent with the Swift data. Our preferred model of the soft excess is emission from an optically thick, warm Comptonizing corona, the effective optical depth of which increases during the anomaly. This model simultaneously explains all three observations: the UV emission-line flux decrease, the soft-excess increase, and the emission-line anomaly

Campaign 9 of the K2 Mission: Observational Parameters, Scientific Drivers, and Community Involvement for a Simultaneous Space- and Ground-based Microlensing Survey

K2's Campaign 9 (K2C9) will conduct a ~3.7 deg2 survey toward the Galactic bulge from 2016 April 22 through July 2 that will leverage the spatial separation between K2 and the Earth to facilitate measurement of the microlens parallax ${\pi }_{{\rm{E}}}$ for $\gtrsim 170$ microlensing events. These will include several that are planetary in nature as well as many short-timescale microlensing events, which are potentially indicative of free-floating planets (FFPs). These satellite parallax measurements will in turn allow for the direct measurement of the masses of and distances to the lensing systems. In this article we provide an overview of the K2C9 space- and ground-based microlensing survey. Specifically, we detail the demographic questions that can be addressed by this program, including the frequency of FFPs and the Galactic distribution of exoplanets, the observational parameters of K2C9, and the array of resources dedicated to concurrent observations. Finally, we outline the avenues through which the larger community can become involved, and generally encourage participation in K2C9, which constitutes an important pathfinding mission and community exercise in anticipation of WFIRST

Conformationally homogeneous heterocyclic pseudotetrapeptides as three-dimensional scaffolds for rational drug design: Receptor-selective somatostatin analogues

A would-be amide: A 1,4-disubstituted 1,2,3-triazole was used as a surrogate for a trans amide bond to create a library of 16 diastereomeric pseudotetrapeptides as beta-turn mimetics. High-resolution structural analysis indicated that these scaffolds adopt distinct, rigid, conformationally homogeneous beta-turn-like structures (see example), some of which bind somatostatin receptor subtypes selectively, and some of which show broad-spectrum activity