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

Comprehensive analysis of epigenetic clocks reveals associations between disproportionate biological ageing and hippocampal volume

The concept of age acceleration, the difference between biological age and chronological age, is of growing interest, particularly with respect to age-related disorders, such as Alzheimer’s Disease (AD). Whilst studies have reported associations with AD risk and related phenotypes, there remains a lack of consensus on these associations. Here we aimed to comprehensively investigate the relationship between five recognised measures of age acceleration, based on DNA methylation patterns (DNAm age), and cross-sectional and longitudinal cognition and AD-related neuroimaging phenotypes (volumetric MRI and Amyloid-β PET) in the Australian Imaging, Biomarkers and Lifestyle (AIBL) and the Alzheimer’s Disease Neuroimaging Initiative (ADNI). Significant associations were observed between age acceleration using the Hannum epigenetic clock and cross-sectional hippocampal volume in AIBL and replicated in ADNI. In AIBL, several other findings were observed cross-sectionally, including a significant association between hippocampal volume and the Hannum and Phenoage epigenetic clocks. Further, significant associations were also observed between hippocampal volume and the Zhang and Phenoage epigenetic clocks within Amyloid-β positive individuals. However, these were not validated within the ADNI cohort. No associations between age acceleration and other Alzheimer’s disease-related phenotypes, including measures of cognition or brain Amyloid-β burden, were observed, and there was no association with longitudinal change in any phenotype. This study presents a link between age acceleration, as determined using DNA methylation, and hippocampal volume that was statistically significant across two highly characterised cohorts. The results presented in this study contribute to a growing literature that supports the role of epigenetic modifications in ageing and AD-related phenotypes

A blood-based biomarker panel indicates IL-10 and IL-12/23p40 are jointly associated as predictors of β-amyloid load in an AD cohort

Alzheimer\u27s Disease (AD) is the most common form of dementia, characterised by extracellular amyloid deposition as plaques and intracellular neurofibrillary tangles of tau protein. As no current clinical test can diagnose individuals at risk of developing AD, the aim of this project is to evaluate a blood-based biomarker panel to identify individuals who carry this risk. We analysed the levels of 22 biomarkers in clinically classified healthy controls (HC), mild cognitive impairment (MCI) and Alzheimer\u27s participants from the well characterised Australian Imaging, Biomarker and Lifestyle (AIBL) study of aging. High levels of IL-10 and IL-12/23p40 were significantly associated with amyloid deposition in HC, suggesting that these two biomarkers might be used to detect at risk individuals. Additionally, other biomarkers (Eotaxin-3, Leptin, PYY) exhibited altered levels in AD participants possessing the APOE ϵ4 allele. This suggests that the physiology of some potential biomarkers may be altered in AD due to the APOE ϵ4 allele, a major risk factor for AD. Taken together, these data highlight several potential biomarkers that can be used in a blood-based panel to allow earlier identification of individuals at risk of developing AD and/or early stage AD for which current therapies may be more beneficial

Vergleich der Reproduzierbarkeit bei Lokalisationsmessungen nach einer Cochlear-Implant-Versorgung, gemessen am erweiterten Mainzer Kindertisch

Hintergrund: Die Überprüfung der Lokalisationsleistung ist ein wichtiger Bestandteil bei der Anpassung von Hörgeräten (HG) und Cochlear-Implantaten (CI). Im Vergleich zu Normalhörenden, zeigen die Patienten mit Hörstörungen zum Teil erhebliche Defizite beim Richtungshören. Grund hierfür liegt in dem eingeschränkten Verarbeitungsprozess, der an beiden Ohren ankommenden Signale. In dieser Studie wird die Lokalisationsleistung von CI-Trägern bezüglich ihrer Reproduzierbarkeit untersucht.Material und Methoden: Die Messungen finden an einem modifizierten Mainzer-Kindertisch (ERKI-Setup) statt (fünf Lautsprecher (LS) an den Positionen 0°, ±45°, ±90°; r=1m). Das den Zielwinkel einschließende LS-Paar wird verwendet, um virtuelle Schallquellen, mittels Lautsprecher Pegeldifferenzen, zu erzeugen. Folglich finden die Lokalisationsmessungen mit einem Mix aus virtuellen und realen Schallquellen statt. Im Bereich von ±70° werden die Stimuli in 10°-Schritten präsentiert, mit einer 10-fachen Messwiederholung pro Winkel. Innerhalb eines Messdurchlaufes erfolgen 150 Schalldarbietungen in randomisierter Reihenfolge. Die verwendeten Stimuli haben jeweils eine Länge von 300 ms und einen Pegel von 65 dB SPL. An den Messungen nehmen erwachsene CI-Träger teil, die in drei Versorgungsgruppen gegliedert werden: SSD (single sided deafness), bimodal (HG+CI) und bilateral (CI+CI). Um eine Aussage über die konventionelle Reproduzierbarkeit der Lokalisationsmessungen mit dem ERKI-Setup treffen zu können, finden die Messungen zusätzlich mit einer Vergleichsgruppe von Normalhörenden statt. Die Aufgabe des Probanden besteht darin, mit Hilfe eines Drehreglers die wahrgenommene Position einer Schallquelle anzugeben. Eine unter der Sichtblende montierte LED-Lichterleiste ermöglicht ein visuelles Feedback.Ergebnisse: Die bisher erhobenen Ergebnisse der Lokalisationsleistungen zeigen Unterschiede zwischen den zwei Probandengruppen (NH vs. CI-Träger) auf. Zudem wurden innerhalb der Gruppe von CI-Trägern verschiedene Lokalisationsmuster erhoben, die stark variieren. So können einige CI-Träger in der Kategorie "Lokalisationsleistung ähnelt der von Normalhörenden" eingestuft werden, während andere der Kategorie "sehr gering ausgeprägtes Lokalisationsvermögen" zugeordnet werden. Ebenso ergeben sich große Streuungen innerhalb der Auswertung zur Reproduzierbarkeit bei der Gruppe der CI-Träger. Ergebnisse aus der laufenden Studie werden vorgestellt

Soil properties and species diversity of grazed crested wheatgrass and native rangelands

Crested wheatgrass (Agropyron cristatum (L.) Gaertn.) is an introduced grass used extensively for rangeland revegetation in the semiarid and arid regions of western North America. The long-term effects of crested wheatgrass on soil properties and plant community were evaluated on 5 grazed sites in the southern interior of British Columbia, Canada. Each site included plant communities of native bluebunch wheatgrass (Pseudoroegneria spicata (Pursh) Scribn. & Smith) and 14- to 60-year-old stands of crested wheatgrass. Soil samples and plant data were collected in June 1997. Species numbers were similar for native and crested wheatgrass rangelands, while the diversity index of crested wheatgrass rangeland was lower due to lower evenness. Crested wheatgrass and native grasses were observed to produce similar amounts of root biomass. Most soil properties were similar under the 2 rangelands. One of the exceptions was soil carbon at 0–7.5 and 7.5–15 cm depths, which was higher on crested wheatgrass than native rangeland. Soil nitrogen at 15–30 cm depth was also higher on crested wheatgrass rangeland. Greater soil penetration resistance was observed at 7.5 and 9 cm depths on crested wheatgrass than native rangeland. Higher soil compaction was caused by grazing of crested wheatgrass earlier in the season when soils are wetter relative to the native rangeland. The results of this study indicate that seeding of crested wheatgrass combined with the long-term grazing by cattle did not result in the degradation of soil properties, but plant diversity was reduced relative to grazed native, bluebunch wheatgrass rangeland.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Entwicklung des Richtungshörens nach einer Cochlear-Implant-Versorgung gemessen mit virtuellen Schallquellen

Ziel dieser prospektiven Längsschnitt-Studie ist die Messung des Richtungshörens bei Patienten, die mit einem Cochlea-Implantat versorgt worden sind. Die Entwicklung des Richtungshörens bei erwachsenen CI-Patienten in der Frühphase der Rehabilitation wurde bereits in der Vergangenheit von einer Münsteraner Arbeitsgruppe um Knief methodisch diskutiert. Dabei wurden Entwicklungen der Genauigkeit mit der einzelne Lautsprecher als Schallquelle erkannt wurden über 6 Monate dargestellt. Die Daten zeigten, dass sich noch kein Plateau ausgebildet hatte, so dass eine weitere Verbesserung angenommen wurde.Es werden die folgenden Gruppen erwachsener CI-Träger gebildet: Erstes CI und beide Ohren an Taubheit grenzend schwerhörig ("CI monaural"), Zweites CI, mit dem ersten ein-jährige Vorerfahrung ("CI bilateral"), SSD-Patienten ("CI-SSD"), Kontrollgruppe bilateraler CI-Trägern. Von der OP beginnen die Messungen in drei bis vier-monatigen Intervallen über mind. 12 Monate. Zur Zeit befinden sich 30 Patienten in der Studie, zwölf in Gruppe 1, fünf in Gruppe 2, zehn in Gruppe 3 und drei Patienten in Gruppe 4. Verwendet wird das ERKI-Setup bestehend aus dem modifizierten MAINZER-Kindertisch mit 32 virtuellen und 5 realen Schallquellen mit einer 5°-Auflösung im vorderen Halbkreis. Vier Stimuli: 300 ms weißes Rauschen, rosa Rauschen, gepulstes rosa Rauschen und den Sprachausschnitt /allo/ aus dem International Speech Test Signal (ISTS).Die Ergebnisse zeigen beispielhaft die Lokalisationsmuster der vier Gruppen zum Messzeitpunkt MP1. Diese Lokalisationsmuster variieren sehr stark.Auch bei CI-Trägern ist im klinischen Alltag das Richtungshören messbar. Die Verteilung der gemessenen Lokalisationsmuster passt zu anderen Arbeiten, die mit 15 realen Lautsprechern an CI-Trägern durchgeführt wurden.Unterstützt durch: EFRE, Promotionsförderung J2P Jade Hochschule, Universität Oldenburg EMS Fak. VI EMS, auritec GmbH HamburgDer Erstautor gibt keinen Interessenkonflikt an

Soil compaction of forest plantations of interior British Columbia

Grazing cattle on forest plantations in the interior of British Columbia (B.C.) is a common practice, but its impact on soil compaction is not well documented. This study evaluated the effects of cattle grazing and forage seeding on soil compaction in lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) plantations near Kamloops, B.C. Grazing regimes consisted of ungrazed exclosures and pastures grazed to achieve 50% utilization of forage vegetation. Seeding treatments were 0 and 12 kg ha-1. Soil bulk density and penetration resistance were determined in 1996 and 1997, before and after the one-month grazing period on study sites grazed since 1989. Water infiltration rates were measured in 1997 after the one-month cattle grazing period. Bulk density was 6% higher on grazed pastures compared to the exclosures. Pastures seeded to domestic forage species had significantly greater soil bulk density at the 0-7.5 cm depth than unseeded pastures. Soil penetration resistance was higher throughout most of the soil profile in the grazed treatments than in the ungrazed exclosures. On pastures without grazing, seeding of the domestic forage species resulted in lower soil penetration resistance relative to unseeded pastures. This was especially true at depths below 6 cm. The rate of water infiltration was not affected by long-term grazing and forage seeding. The bulk density and penetration resistance data indicate that plantation grazing at 50% forage utilization does not lead to root-limiting increases in soil compaction.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202