889 research outputs found
Wave-vector dependent intensity variations of the Kondo peak in photoemission from CePd
Strong angle-dependent intensity variations of the Fermi-level feature are
observed in 4d - 4f resonant photoemission spectra of CePd(111), that
reveal the periodicity of the lattice and largest intensity close to the Gamma
points of the surface Brillouin zone. In the framework of a simplified periodic
Anderson model the phenomena may quantitatively be described by a wave-vector
dependence of the electron hopping matrix elements caused by Fermi-level
crossings of non-4f-derived energy bands
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Impacts devalue the potential of large-scale terrestrial CO2 removal through biomass plantations
Large-scale biomass plantations (BPs) are often considered a feasible and safe climate engineering proposal for extracting carbon from the atmosphere and, thereby, reducing global mean temperatures. However, the capacity of such terrestrial carbon dioxide removal (tCDR) strategies and their larger Earth system impacts remain to be comprehensively studiedâeven more so under higher carbon emissions and progressing climate change. Here, we use a spatially explicit process-based biosphere model to systematically quantify the potentials and trade-offs of a range of BP scenarios dedicated to tCDR, representing different assumptions about which areas are convertible. Based on a moderate CO2 concentration pathway resulting in a global mean warming of 2.5 °C above preindustrial level by the end of this centuryâsimilar to the Representative Concentration Pathway (RCP) 4.5âwe assume tCDR to be implemented when a warming of 1.5 °C is reached in year 2038. Our results show that BPs can slow down the progression of increasing cumulative carbon in the atmosphere only sufficiently if emissions are reduced simultaneously like in the underlying RCP4.5 trajectory. The potential of tCDR to balance additional, unabated emissions leading towards a business-as-usual pathway alike RCP8.5 is therefore very limited. Furthermore, in the required large-scale applications, these plantations would induce significant trade-offs with food production and biodiversity and exert impacts on forest extent, biogeochemical cycles and biogeophysical properties
Shifting the Burden of Proof on Causation in Legal Malpractice Actions.
Legal malpractice suits, like any negligence claim, require the plaintiff to meet all of the elements of the malpractice claim. Texas malpractice claims are based on professional negligence. In Texas, the elements a plaintiff must prove in a legal malpractice claim are: (1) the attorney owed the plaintiff a duty; (2) the attorney breached that duty; (3) the breach proximately caused the plaintiffs injuries; and (4) damages occurred. Most jurisdictions, including Texas, place the burden on the plaintiff to meet all elements of the claim, including causation. However, a significant minority of jurisdictions allow the burden to shift to the defendant after the plaintiff presents a prima facie case of negligence
Apes communicate about absent and displaced objects: methodology matters
Displaced reference is the ability to refer to an item that has been moved (displaced) in space and/or time, and has been called one of the true hallmarks of referential communication. Several studies suggest that nonhuman primates have this capability, but a recent experiment concluded that in a specific situation (absent entities) human infants display displaced reference but chimpanzees do not. Here we show that chimpanzees and bonobos of diverse rearing histories are capable of displaced reference to absent and displaced objects. It is likely that some of the conflicting findings from animal cognition studies are due to relatively minor methodological differences, but are compounded by interpretation errors. Comparative studies are of great importance in elucidating the evolution of human cognition, however, greater care must be taken with methodology and interpretation for these studies to accurately reflect species differences
Identifizierung VHL-assoziierter VerÀnderungen im klarzelligen Nierenzellkarzinom: Anwendung von kombinierten Genom- und Expressionsanalysen
Zusammenfassung: Das sporadische Nierenzellkarzinom (NZK) ist ein heterogener solider Tumor, der traditionell basierend auf morphologischen Kriterien in weitere Subtypen unterteilt wird. In den letzten Jahren konnten unter Anwendung molekularer Hochdurchsatzanalysen genetische, transkriptionelle und translationale Alterationen identifiziert werden. Diese Marker eignen sich zum einen fĂŒr die molekulare Klassifizierung des NZK und haben zum anderen prognostische Wertigkeit. Die isolierte Betrachtung genetischer, transkriptioneller und translationaler VerĂ€nderungen verhindert jedoch ein tieferes VerstĂ€ndnis fĂŒr die komplexen VorgĂ€nge der Karzinogenese. Wir fassen hier aktuelle Forschungsergebnisse zur molekularen Charakterisierung des NZK zusammen und stellen ein systembiologisches Konzept zur Identifizierung neuer Tumormarker vor. Diese könnten zukĂŒnftig Einsatz in der Diagnostik und Therapie des sporadischen NZK finde
The limits to global-warming mitigation by terrestrial carbon removal
This is the final version of the article. Available from Wiley via the DOI in this record.Massive near-term greenhouse gas emissions reduction is a precondition for staying âwell below 2°Câ global warming as envisaged by the Paris Agreement. Furthermore, extensive terrestrial carbon dioxide removal (tCDR) through managed biomass growth and subsequent carbon capture and storage is required to avoid temperature âovershootâ in most pertinent scenarios. Here, we address two major issues: First, we calculate the extent of tCDR required to ârepairâ delayed or insufficient emissions reduction policies unable to prevent global mean temperature rise of 2.5°C or even 4.5°C above pre-industrial level. Our results show that those tCDR measures are unable to counteract âbusiness-as-usualâ emissions without eliminating virtually all natural ecosystems. Even if considerable (Representative Concentration Pathway 4.5 [RCP4.5]) emissions reductions are assumed, tCDR with 50% storage efficiency requires > 1.1 Gha of the most productive agricultural areas or the elimination of > 50% of natural forests. In addition, > 100 MtN/yr fertilizers would be needed to remove the roughly 320 GtC foreseen in these scenarios. Such interventions would severely compromise food production and/or biosphere functioning. Second, we reanalyze the requirements for achieving the 160â190 GtC tCDR that would complement strong mitigation action (RCP2.6) in order to avoid 2°C overshoot anytime. We find that a combination of high irrigation water input and/or more efficient conversion to stored carbon is necessary. In the face of severe trade-offs with society and the biosphere, we conclude that large-scale tCDR is not a viable alternative to aggressive emissions reduction. However, we argue that tCDR might serve as a valuable âsupporting actorâ for strong mitigation if sustainable schemes are established immediately.This study was funded by the German Research Foundation's priority program DFG SPP 1689 on âClimate Engineering â Risks, Challenges and Opportunities?â and specifically the CE-LAND project. T.M.L. was supported by a Royal Society Wolfson Research Merit Award
Diphenyleneiodonium acutely inhibits reactive oxygen species production by mitochondrial complex I during reverse, but not forward electron transport
AbstractWe investigated the effects of diphenyleneiodonium (DPI) on superoxide production by complex I in mitochondria isolated from rat skeletal muscle. Superoxide production was measured indirectly as hydrogen peroxide production. In a conventional medium containing chloride, DPI strongly inhibited superoxide production by complex I driven by reverse electron transport from succinate. In principle, this inhibition could be explained by an observed decrease in the mitochondrial pH gradient caused by the known chlorideâhydroxide antiport activity of DPI. In a medium containing gluconate instead of chloride, DPI did not affect the pH gradient. In this gluconate medium, DPI still inhibited superoxide production driven by reverse electron transport, showing that the inhibition of superoxide production was not dependent on changes in the pH gradient. It had no effect on superoxide production during forward electron transport from NAD-linked substrates in the presence of rotenone (to maximise superoxide production from the flavin of complex I) or antimycin (to maximise superoxide production from complex III), suggesting that the effects of DPI were not through inhibition of the flavin. We conclude that DPI has the novel and potentially very useful ability to prevent superoxide production from the site in complex I that is active during reverse electron transport, without affecting superoxide production during forward electron transport
Use of decongestants may disrupt cell signaling pathways that control Tbx gene expression, leading to hypoplastic left heart syndrome
Hypoplastic left heart syndrome (HLHS) collectively refers to a range of congenital heart defects, all involving some degree of left ventricular hypoplasia, or underdevelopment of the left ventricle. Additionally, HLHS often involves coarctation of the aorta, and can also include hypoplasia of the ascending aorta, as well as mitral and/or aortic valve stenosis or atresia. HLHS is extremely rare, as it has been reported to occur in only 1 in 5000 live births each year. The cause of HLHS is currently unknown, however much research is being done to discover how and why these defects occur.
HLHS is known to be familially inherited in some instances and is also associated with many well-characterized genetic disorders, including Holt-Oram syndrome, Turnerâs syndrome, Noonan syndrome, Smith-Lemli-Opitz syndrome, as well as trisomies 13, 18, and 21. Additionally, an autosomal recessive pattern of inheritance has been found amongst some siblings, however, no specific genes have been implicated. Incidence of HLHS also varies significantly in certain geographical regions and some studies have found a seasonal correlation in HLHS, indicating a possible environmental cause
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