Primary aragonite and high-Mg calcite in the late Cambrian (Furongian) : Potential evidence from marine carbonates in Oman

Acknowledgements Fieldwork and sampling was funded by Petroleum Development Oman during S. Al Marjibis's Ph.D. Their help is gratefully acknowledged. We also thank colleagues at the University of Aberdeen, Julie Dougans (SUERC) for assisting with stable isotope analysis and Dr. Richard Hinton (EIMF) for assistance with ion microprobe analysis. Profs. Kiessling, Tucker, Bosence, Coleman, Dr. Dickson and an anonymous reviewer are thanked for their helpful and encouraging comments.Peer reviewedPostprin

Simple Optimization Method to Determine Best Management Practices to Reduce Phosphorus Loading in Echo Reservoir, Utah

This study develops and applies a simple linear optimization program to identify cost effective Best Management Practices (BMPs) to reduce phosphorus loading to Echo Reservoir, Utah. The optimization program tests the feasibility of proposed Total Maximum Daily Load (TMDL) allocations based on potential BMP options and provides information regarding the spatial redistribution of loads among sub-watersheds. The current version of the TMDL for Echo reservoir allocates phosphorus loads to existing non-point phosphorus sources in different sub-watersheds to meet a specified total load. Optimization results show that it is feasible to implement BMPs for non-point sources in each sub-watershed to meet reduction targets at a cost of $1.0 million. However, relaxing these targets can achieve the overall target at lower cost. The optimization program and results provide a simple tool to test the feasibility of proposed TMDL allocations based on potential BMP options and can also recommend spatial redistributions of loads among sub-watersheds to lower costs

CHARA/MIRC observations of two M supergiants in Perseus OB1: temperature, Bayesian modeling, and compressed sensing imaging

Two red supergiants of the Per OB1 association, RS Per and T Per, have been observed in H band using the MIRC instrument at the CHARA array. The data show clear evidence of departure from circular symmetry. We present here new techniques specially developed to analyze such cases, based on state-of-the-art statistical frameworks. The stellar surfaces are first modeled as limb-darkened discs based on SATLAS models that fit both MIRC interferometric data and publicly available spectrophotometric data. Bayesian model selection is then used to determine the most probable number of spots. The effective surface temperatures are also determined and give further support to the recently derived hotter temperature scales of red su- pergiants. The stellar surfaces are reconstructed by our model-independent imaging code SQUEEZE, making use of its novel regularizer based on Compressed Sensing theory. We find excellent agreement between the model-selection results and the reconstructions. Our results provide evidence for the presence of near-infrared spots representing about 3-5% of the stellar flux

Many-body correlations probed by plasmon-enhanced drag measurements in double quantum well structures

Electron drag measurements of electron-electron scattering rates performed close to the Fermi temperature are reported. While evidence of an enhancement due to plasmons, as was recently predicted [K. Flensberg and B. Y.-K. Hu, Phys. Rev. Lett. 73, 3572 (1994)], is found, important differences with the random-phase approximation based calculations are observed. Although static correlation effects likely account for part of this difference, it is argued that correlation-induced multiparticle excitations must be included to account for the magnitude of the rates and observed density dependences.Comment: 4 pages, 3 figures, revtex Accepted in Phys. Rev.

Stressabhängige Ribonukleoproteinkomplex Formation in der Kontrolle der Prothrombin Genexpression

Die 3´Endprozessierung ist neben dem Capping und Spleißen ein wichtiger posttrans-kriptioneller Genexpressionsmechanismus. Die Prothrombin (F2) mRNA ist ein Prototyp für eine Genfamilie, die ein ungewöhnliches RNA Sequenz Motiv in der 3´ untranslatierten Regi-on aufweist. Stromaufwärts des Polyadenylierungssignals befindet sich ein Sequenzelement (USE), welches die 3´Endprozessierung sequenz- und positionsanhängig stimuliert. Dabei fungieren interessanterweise einige Spleißfaktoren (hnRNPI, U2AF35 und U2AF65) als posi-tive F2 USE-Effektorproteine, indem sie den kanonischen 3´Endprozessierungsapparat an die prä-mRNA rekrutieren. Des Weiteren wurden AU-reiche elementbindende Proteine (sog. ARE-BPs) als hochaffine und spezifische F2 USE Interaktionspartner identifiziert, deren po-tentielle Bedeutung in der 3´Endprozessierung bisher nicht beschrieben und analysiert wurde. Ziel dieser Arbeit war es die Ribonukleoprotein (RNP) Komposition exemplarisch an dem F2 USE Motiv unter Stressbedingungen zu analysieren und dessen Einfluss auf die Regulation der 3´Endprozessierung zu untersuchen. In molekularen Analysen des F2 USE RNP Komplexes konnte gezeigt werden, dass die meis-ten ARE-BPs direkt und spezifisch an das USE Motiv binden. Stress führt zur Hyperphospho-rylierung von einigen der ARE-BPs (FBP2 und FBP3) und reduziert deren Bindungsaffinität zum F2 USE Motiv. Somit scheinen die FBPs als Stresssensoren zu fungieren, wodurch die Komposition des F2 USE RNP Komplexes dynamisch an physiologische Prozesse angepasst werden kann. Diese und weitere im Labor generierten Daten deuten darauf hin, dass FBP2 und FBP3 wahrscheinlich stressabhängig mit den positiven USE-Effektorproteinen um die Bindung an das F2 USE Motiv konkurrieren. Um die Frage zu beantworten, ob die 3´Endprozessierung der F2 mRNA unter Stressbedin-gungen reguliert wird, wurden stabile Reporter-Zelllinien generiert. In Stressexperimenten verhielten sich die stabilen Zellklone sehr heterogen bzgl. der Regulation der 3´Endprozessierung, was möglicherweise mit der zufälligen Integration der Tandemreporter in das Genom zu erklären ist. Trotz dieser Variabilität deuten aber diese in vivo Daten auf eine USE-abhängige Regulation der 3´Endprozessierung hin, was jedoch mit neuen experimentel-len Ansätzen wie zum Beispiel lokusspezifischen, stabil transfizierten Zelllinien zu prüfen ist. Insgesamt zeigt die hier vorgestellte Arbeit, dass die regulierte 3´Endprozessierung eine be-deutende Rolle bei der stressabhängigen Adaptation der Genexpression spielt

Quantifying Thermal Refugia Connectivity by Combining Temperature Modeling, Distributed Temperature Sensing, and Thermal Infrared Imaging

Watershed-scale stream temperature models are often one-dimensional because they require fewer data and are more computationally efficient than two- or three-dimensional models. However, one-dimensional models assume completely mixed reaches and ignore small-scale spatial temperature variability, which may create temperature barriers or refugia for cold-water aquatic species. Fine spatial- and temporal-resolution stream temperature monitoring provides information to identify river features with increased thermal variability. We used distributed temperature sensing (DTS) to observe small-scale stream temperature variability, measured as a temperature range through space and time, within two 400 m reaches in summer 2015 in Nevada\u27s East Walker and main stem Walker rivers. Thermal infrared (TIR) aerial imagery collected in summer 2012 quantified the spatial temperature variability throughout the Walker Basin. We coupled both types of high-resolution measured data with simulated stream temperatures to corroborate model results and estimate the spatial distribution of thermal refugia for Lahontan cutthroat trout and other cold-water species. Temperature model estimates were within the DTS-measured temperature ranges 21 % and 70 % of the time for the East Walker River and main stem Walker River, respectively, and within TIR-measured temperatures 17 %, 5 %, and 5 % of the time for the East Walker, West Walker, and main stem Walker rivers, respectively. DTS, TIR, and modeled stream temperatures in the main stem Walker River nearly always exceeded the 21 ∘C optimal temperature threshold for adult trout, usually exceeded the 24 ∘C stress threshold, and could exceed the 28 ∘C lethal threshold for Lahontan cutthroat trout. Measured stream temperature ranges bracketed ambient river temperatures by −10.1 to +2.3 ∘C in agricultural return flows, −1.2 to +4 ∘C at diversions, −5.1 to +2 ∘C in beaver dams, and −4.2 to 0 ∘C at seeps. To better understand the role of these river features on thermal refugia during warm time periods, the respective temperature ranges were added to simulated stream temperatures at each of the identified river features. Based on this analysis, the average distance between thermal refugia in this system was 2.8 km. While simulated stream temperatures are often too warm to support Lahontan cutthroat trout and other cold-water species, thermal refugia may exist to improve habitat connectivity and facilitate trout movement between spawning and summer habitats. Overall, high-resolution DTS and TIR measurements quantify temperature ranges of refugia and augment process-based modeling

Disease Progression-Dependent Effects of TREM2 Deficiency in a Mouse Model of Alzheimer's Disease

Neuroinflammation is an important contributor to Alzheimer's disease (AD) pathogenesis, as underscored by the recent identification of immune-related genetic risk factors for AD, including coding variants in the gene TREM2 (triggering receptor expressed on myeloid cells 2). Understanding TREM2 function promises to provide important insights into how neuroinflammation contributes to AD pathology. However, studies so far have produced seemingly conflicting results, with reports that amyloid pathology can be both decreased and increased in TREM2-deficient AD mouse models. In this study, we unify these previous findings by demonstrating that TREM2 deficiency ameliorates amyloid pathology early, but exacerbates it late in disease progression in the APPPS1–21 mouse model of AD. We also demonstrate that TREM2 deficiency decreases plaque-associated myeloid cell accumulation by reducing cell proliferation, specifically late in pathology. In addition, TREM2 deficiency reduces myeloid cell internalization of amyloid throughout pathology, but decreases inflammation-related gene transcript levels selectively late in disease progression. Together, these results suggest that TREM2 plays distinct functional roles at different stages in AD pathology

Liquid Xenon Detectors for Positron Emission Tomography

PET is a functional imaging technique based on detection of annihilation photons following beta decay producing positrons. In this paper, we present the concept of a new PET system for preclinical applications consisting of a ring of twelve time projection chambers filled with liquid xenon viewed by avalanche photodiodes. Simultaneous measurement of ionization charge and scintillation light leads to a significant improvement to spatial resolution, image quality, and sensitivity. Simulated performance shows that an energy resolution of <10% (FWHM) and a sensitivity of 15% are achievable. First tests with a prototype TPC indicate position resolution <1 mm (FWHM).Comment: Paper presented at the International Nuclear Physics Conference, Vancouver, Canada, 201

Highly regioselective iodination of arenes via iron(III)-catalyzed activation of N-iodosuccinimide

An iron(III)-catalyzed method for the rapid and highly regioselective iodination of arenes has been developed. Use of the powerful Lewis acid, iron(III) triflimide, generated in situ from iron(III) chloride and a readily available triflimide-based ionic liquid allowed activation of N-iodosuccinimide (NIS) and efficient iodination under mild conditions of a wide range of substrates including biologically active compounds and molecular imaging agents