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Novel heating/cooling stage designed for fluid inclusion microthermometry of large stalagmite sections
Liquidâvapour homogenisation temperatures of fluid inclusions in stalagmites are used for quantitative temperature reconstructions in paleoclimate research. Specifically for this application, we have developed a novel heating/cooling stage that can be operated with large stalagmite sections of up to 17 Ă 35 mm2 to simplify and improve the chronological reconstruction of paleotemperature time-series. The stage is designed for use of an oil immersion objective and a high-NA condenser front lens to obtain high-resolution images for bubble radius measurements. The temperature accuracy of the stage is better than ± 0.1 °C with a precision (reproducibility) of ± 0.02 °C
Pressure-driven Instabilities in Cylindrical Geometry: A New General Criterion
A new criterion for pressure-driven interchange instabilities in cylindrical
geometry is derived, based on an alternate use of the Energy Principle. This
criterion is inequivalent to Suydam's criterion and does not contain the
magnetic shear. In fact, it is shown that Suydam's criterion relates to the
instability of the slow magnetosonic branch, while the present criterion
relates to the Alfv\'enic one, which is the most dangerous of the two. These
findings explain why pressure-driven modes nearly always exist even if Suydam's
criterion is satisfied by a large margin.Comment: 4 pages. Submitted to Phys. Rev. Let
Exploration of the phase diagram of liquid water in the low-temperature metastable region using synthetic fluid inclusions
We present new experimental data of the low-temperature metastable region of liquid water derived from high-density synthetic fluid inclusions (996-916 kg m-3) in quartz. Microthermometric measurements include: (i) prograde (upon heating) and retrograde (upon cooling) liquid-vapour homogenisation. We used single ultrashort laser pulses to stimulate vapour bubble nucleation in initially monophase liquid inclusions. Water densities were calculated based on prograde homogenisation temperatures using the IAPWS-95 formulation. We found retrograde liquid-vapour homogenisation temperatures in excellent agreement with IAPWS-95. (ii) Retrograde ice nucleation. Raman spectroscopy was used to determine the nucleation of ice in the absence of the vapour bubble. Our ice nucleation data in the doubly metastable region are inconsistent with the low-temperature trend of the spinodal predicted by IAPWS-95, as liquid water with a density of 921 kg m-3 remains in a homogeneous state during cooling down to a temperature of -30.5 °C, where it is transformed into ice whose density corresponds to zero pressure. (iii) Ice melting. Ice melting temperatures of up to 6.8 °C were measured in the absence of the vapour bubble, i.e. in the negative pressure region. (iv) Spontaneous retrograde and, for the first time, prograde vapour bubble nucleation. Prograde bubble nucleation occurred upon heating at temperatures above ice melting. The occurrence of prograde and retrograde vapour bubble nucleation in the same inclusions indicates a maximum of the bubble nucleation curve in the ϱ-T plane at around 40 °C. The new experimental data represent valuable benchmarks to evaluate and further improve theoretical models describing the p-V-T properties of metastable water in the low-temperature region
Das DLR-Projekt KonTeKst: Konzepte und Technologien fĂŒr emissionsarme Kurzstreckenflugzeuge
Das Paper gibt eine Ăbersicht ĂŒber die Arbeiten und Ergebnisse im Projekt KonTeKst. Im Projekt wurden im ersten Hauptarbeitspaket zwei Flugzeugkonfigurationen mit einer konfigurativen LĂ€rmreduktion im Vergleich zu einem Referenzflugzeug entworfen sowie hinsichtlich Leistung, LĂ€rmabstrahlung und Emissionen bewertet. Das zweite Hauptarbeitspaket befasste sich mit ausgewĂ€hlten Technologien, die im Bereich des Kurzstreckenflugzeugs die LĂ€rmreduktion am Flugzeug zum Ziel haben. Dazu gehörten Untersuchungen an Hochauftriebshilfen sowie MaĂnahmen zur ihrer konstruktiven Gestaltung sowie Analysen des LĂ€rmverhalten unterschiedlicher Treibwerkskonfigurationen. Im dritten Hauptarbeitspaket wurde der DLR-ĂŒbergreifende Lastenprozess um spezifische FunktionalitĂ€ten erweitert. Die Verfahren wurden durch experimentelle Untersuchungen, so z. B. Auswertungen von Flugversuchen sowie DurchfĂŒhrung eines Windkanalversuches fĂŒr aktive und passive Lastabminderung von Böenlasten, validiert. Im Hauptarbeitspaket vier wurden die Auswirkungen des Einsatzprofils von Kurzstreckenflugzeugen, d. h. eine höheren Anzahl von Starts- und Landungen pro Tag, auf den Flughafen, die Prozesse fĂŒr die Abfertigung von Passagieren und Fracht sowie fĂŒr die FĂŒhrung des Flugzeugs am Boden und in der Luft untersucht.
ZunĂ€chst wird die Motivation des Projekts herausgearbeitet, vor allem vor dem Hintergrund der Leitkonzepte des DLR. AnschlieĂend werden die Arbeiten im Projekt kurz vorgestellt und projektĂŒbergreifende Ergebnisse prĂ€sentiert. SchlieĂlich wird ein Ausblick auf die weitere Arbeit im neuen Leitkonzept 'Transportflugzeug' gegeben
Multi-proxy speleothem-based reconstruction of mid-MIS 3 climate in South Africa
The southern coast of South Africa displays a highly dynamical climate as it is at the convergence of both the Atlantic and Indian Ocean, and it is located near the subtropical/temperate zone boundary with seasonal influence of easterlies/westerlies. The region hosts some key archeological sites with records of significant cognitive, technological and social developments. Reconstructions of the state and variability of past climate and environmental conditions around sites of archeological significance can provide crucial context for understanding the evolution of early humans. Here we present a short but high-resolution record of hydroclimate and temperature in South Africa. Our reconstructions are based on trace elements, calcite and fluid inclusion stable isotopes, and fluid inclusion microthermometry from a speleothem collected in Bloukrantz Cave, in the De Hoop Nature Reserve in the Western Cape region of South Africa. Our record covers the time period from 48.3 to 45.2 ka during Marine Isotope Stage 3. Both 18Oc and 13Cc show strong variability and covary with Sr/Ca. This correlation suggests that the control on these proxies originates from internal cave processes such as Prior Calcite Precipitation, which we infer to be related to precipitation amount. The hydroclimate indicators furthermore suggest a shift towards overall drier conditions after 46 ka, coincident with a cooling in Antarctica and drier conditions in the eastern part of South Africa corresponding to the Summer Rainfall Zone. Fluid inclusion-based temperature reconstructions show good agreement between the oxygen isotope and microthermometry methods, and results from the latter display little variation throughout the record, with reconstructed temperatures close to the present-day cave temperature of 17.5 °C. Overall, the BL3 record thus suggests stable temperature from 48.3 to 45.2 ka whereas precipitation was variable with marked drier episodes on sub-millennial timescales.</p
Zum Zusammenhang von Geschlechterungleichheiten in Bildung, Beruf und Karriere : ein Ausblick
Ziel der folgenden AusfĂŒhrungen im abschliessenden Teil dieses Sammelbands zur Entwicklung und Genese von geschlechtsspezifischen Bildungsungleichheiten ist es, den Blick zu öffnen in Richtung Berufsleben. Wie sind die verbesserten Bildungsmöglichkeiten von Frauen zu interpretieren? Ist es in den letzten Jahrzehnten gelungen, eines der grundlegendsten gesellschaftlichen UngleichheitsverhĂ€ltnisse zu beseitigen? Oder beginnt sich dieses sogar zu verkehren in eine gesellschaftliche Benachteiligung der MĂ€nner? Wir gehen bei unseren Ăberlegungen von der These aus, dass ein Abbau von Benachteiligungen der Frauen im Bildungssystem fĂŒr sich genommen noch wenig aussagekrĂ€ftig ist, wenn wir uns mit der klassischen soziologischen Frage der Persistenz bzw. des Wandels von gesellschaftlichen Ungleichheiten befassen wollen. Erst wenn die ganze VerknĂŒpfung von Bildung und gesellschaftlicher Ungleichheit in den Blick genommen wird und sich dabei zeigt, dass Frauen ihre Bildungsgewinne auch in entsprechende Chancen im BeschĂ€ftigungssystem umsetzen können, sind ihre verbesserten Bildungschancen ein Gewinn fĂŒr die Individuen und ein Fortschritt fĂŒr die Gesellschaft â und erst dann könnten mögliche Bildungsvorteile von Frauen, wie sie in den vorliegenden AufsĂ€tzen z.T. diagnostiziert werden, gar als neue gesellschaftliche Benachteiligungen von MĂ€nnern skandalisiert werden
Validation of a SARS-CoV-2 Surrogate Neutralization Test Detecting Neutralizing Antibodies against the Major Variants of Concern.
peer reviewedSARS-CoV-2 infection and/or vaccination elicit a broad range of neutralizing antibody responses against the different variants of concern (VOC). We established a new variant-adapted surrogate virus neutralization test (sVNT) and assessed the neutralization activity against the ancestral B.1 (WT) and VOC Delta, Omicron BA.1, BA.2, and BA.5. Analytical performances were compared against the respective VOC to the reference virus neutralization test (VNT) and two CE-IVD labeled kits using three different cohorts collected during the COVID-19 waves. Correlation analyses showed moderate to strong correlation for Omicron sub-variants (Spearman's r = 0.7081 for BA.1, r = 0.7205 for BA.2, and r = 0.6042 for BA.5), and for WT (r = 0.8458) and Delta-sVNT (r = 0.8158), respectively. Comparison of the WT-sVNT performance with two CE-IVD kits, the "Icosagen SARS-CoV-2 Neutralizing Antibody ELISA kit" and the "Genscript cPass, kit" revealed an overall good correlation ranging from 0.8673 to -0.8773 and a midway profile between both commercial kits with 87.76% sensitivity and 90.48% clinical specificity. The BA.2-sVNT performance was similar to the BA.2 Genscript test. Finally, a correlation analysis revealed a strong association (r = 0.8583) between BA.5-sVNT and VNT sVNT using a double-vaccinated cohort (n = 100) and an Omicron-breakthrough infection cohort (n = 91). In conclusion, the sVNT allows for the efficient prediction of immune protection against the various VOCs
Global assessment of marine plastic exposure risk for oceanic birds
Plastic pollution is distributed patchily around the worldâs oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species
Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences
The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & NemĂ©sio 2007; Donegan 2008, 2009; NemĂ©sio 2009aâb; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported
by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on
18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based
researchers who signed it in the short time span from 20 September to 6 October 2016
Impact of KIT exon 10 M541L allelic variant on the response to imatinib in aggressive fibromatosis: analysis of the desminib series by competitive allele specific Taqman PCR technology
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