Effects of Acid Deposition on Dissolution of Carbonate Stone During Summer Storms in the Adirondack Mountains, New York, 1987-89

This study is part of a long-term research program designed to identify and quantify acid rain damage to carbonate stone. Acidic deposition accelerates the dissolution of carbonate-stone monuments and building materials. Sequential sampling of runoff from carbonate-stone (marble) and glass (reference) microcatchments in the Adirondack Mountains in New York State provided a detailed record of the episodic fluctuations in rain rate and runoff chemistry during individual summer storms. Rain rate and chemical concentrations from carbonate-stone and glass runoff fluctuated three to tenfold during storms. Net calcium-ion concentrations from the carbonatestone runoff, a measure of stone dissolution, typically fluctuated twofold during these storms. High net sulfate and net calcium concentrations in the first effective runoff at the start of a storm indicated that atmospheric pollutants deposited on the stone surface during dry periods formed calcium sulfate minerals, an important process in carbonate stone dissolution. Dissolution of the carbonate stone generally increased up to twofold during coincident episodes of low rain rate (less than 5 millimeters per hour) and decreased rainfall (glass runoff) pH (less than 4.0); episodes of high rain rate (cloudbursts) were coincident with a rapid increase in rainfall pH and also a rapid decrease in the dissolution of carbonate-stone. During a storm, it seems the most important factors causing increased dissolution of carbonate stone are coincident periods of low rain rate and decreased rainfall pH. Dissolution of the carbonate stone decreased slightly as the rain rate exceeded about 5 millimeters per hour, probably in response to rapidly increasing rainfall pH during episodes of high rain rate and shorter contact time between the runoff and the stone surface. High runoff rates resulting from cloudbursts remove calcium sulfate minerals formed during dry periods prior to storms and also remove dissolution products formed in large measure by chemical weathering as a result of episodes of low rain rate and decreased rainfall pH during a storm

Increasing aeolian dust deposition to snowpacks in the Rocky Mountains inferred from snowpack, wet deposition, and aerosol chemistry

AbstractMountain snowpacks are a vital natural resource for ∼1.5 billion people in the northern Hemisphere, helping to meet human and ecological demand for water in excess of that provided by summer rain. Springtime warming and aeolian dust deposition accelerate snowmelt, increasing the risk of water shortages during late summer, when demand is greatest. While climate networks provide data that can be used to evaluate the effect of warming on snowpack resources, there are no established regional networks for monitoring aeolian dust deposition to snow. In this study, we test the hypothesis that chemistry of snow, wet deposition, and aerosols can be used as a surrogate for dust deposition to snow. We then analyze spatial patterns and temporal trends in inferred springtime dust deposition to snow across the Rocky Mountains, USA, for 1993–2014. Geochemical evidence, including strong correlations (r2 ≥ 0.94) between Ca2+, alkalinity, and dust concentrations in snow deposited during dust events, indicate that carbonate minerals in dust impart a strong chemical signature that can be used to track dust deposition to snow. Spatial patterns in chemistry of snow, wet deposition, and aerosols indicate that dust deposition increases from north to south in the Rocky Mountains, and temporal trends indicate that winter/spring dust deposition increased by 81% in the southern Rockies during 1993–2014. Using a multivariate modeling approach, we determined that increases in dust deposition and decreases in springtime snowfall combined to accelerate snowmelt timing in the southern Rockies by approximately 7–18 days between 1993 and 2014. Previous studies have shown that aeolian dust emissions may have doubled globally during the 20th century, possibly due to drought and land-use change. Climate projections for increased aridity in the southwestern U.S., northern Africa, and other mid-latitude regions of the northern Hemisphere suggest that aeolian dust emissions may continue to increase, compounding the risk that climate warming poses to snowpack water resources in arid/semi-arid regions of the world

Vulnerability of Subsistence Systems Due to Social and Environmental Change: A Case Study in the Yukon-Kuskokwim Delta, Alaska

Arctic Indigenous communities have been classified as highly vulnerable to climate change impacts. The remoteness of Arctic communities, their dependence upon local species and habitats, and the historical marginalization of Indigenous peoples enhances this characterization of vulnerability. However, vulnerability is a result of diverse historical, social, economic, political, cultural, institutional, natural resource, and environmental conditions and processes and is not easily reduced to a single metric. Furthermore, despite the widespread characterization of vulnerability, Arctic Indigenous communities are extremely resilient as evidenced by subsistence institutions that have been developed over thousands of years. We explored the vulnerability of subsistence systems in the Cup’ik village of Chevak and Yup’ik village of Kotlik through the lens of the strong seasonal dimensions of resource availability. In the context of subsistence harvesting in Alaska Native villages, vulnerability may be determined by analyzing the exposure of subsistence resources to climate change impacts, the sensitivity of a community to those impacts, and the capacity of subsistence institutions to absorb these impacts. Subsistence resources, their seasonality, and perceived impacts to these resources were investigated via semi-structured interviews and participatory mapping-calendar workshops. Results suggest that while these communities are experiencing disproportionate impacts of climate change, Indigenous ingenuity and adaptability provide an avenue for culturally appropriate adaptation strategies. However, despite this capacity for resiliency, rapid socio-cultural changes have the potential to be a barrier to community adaptation and the recent, ongoing shifts in seasonal weather patterns may make seasonally specific subsistence adaptations to landscape particularly vulnerable.Les collectivités autochtones de l’Arctique sont classées comme étant fortement vulnérables aux incidences du changement climatique. L’éloignement des collectivités de l’Arctique, leur dépendance des espèces et des habitats locaux de même que la marginalisation historique des peuples autochtones intensifient cette vulnérabilité. Toutefois, la vulnérabilité est le résultat de conditions et de processus divers sur le plan historique, social, économique, politique, culturel, institutionnel, environnemental et des ressources naturelles. Il est difficile d’attribuer la vulnérabilité à un seul aspect. Malgré cette vaste caractérisation de la vulnérabilité, les collectivités autochtones de l’Arctique sont extrêmement résilientes, comme en attestent les modes de subsistance qui se sont développés au fil de milliers d’années. Nous avons exploré la vulnérabilité des systèmes de subsistance du village cup’ik de Chevak et du village yup’ik de Kotlik du point de vue des dimensions saisonnières fortes de la disponibilité des ressources. Dans le contexte des récoltes de subsistance des villages autochtones de l’Alaska, la vulnérabilité peut être déterminée au moyen de l’exposition des ressources de subsistance aux incidences du changement climatique, de la sensibilité d’une collectivité à ces incidences et de la capacité des institutions de subsistance à absorber ces incidences. Les ressources de subsistance, leur saisonnalité et les incidences perçues de ces ressources ont été étudiées au moyen d’entrevues semi-structurées et d’ateliers participatifs d’établissement de calendrier. Selon les résultats, bien que ces collectivités soient aux prises avec des incidences disproportionnées de changement climatique, l’ingéniosité et l’adaptabilité des Autochtones pavent le chemin à des stratégies d’adaptation convenant à leur culture. Cependant, malgré cette capacité de résilience, les changements socioculturels accélérés ont la possibilité de faire obstacle à l’adaptation collective, sans compter que la variation continue des tendances climatiques saisonnières peut rendre les adaptations de subsistance saisonnières au paysage particulièrement vulnérables

Short-Term Impact of Bracing in Multi-Level Posterior Lumbar Spinal Fusion

Background: Clinical practice in postoperative bracing after posterior lumbar spine fusion (PLF) is inconsistent between providers. This paper attempts to assess the effect of bracing on short-term outcomes related to safety, quality of care, and direct costs. Methods: Retrospective cohort analysis of consecutive patients undergoing multilevel PLF with or without bracing (2013-2017) was undertaken (n = 980). Patient demographics and comorbidities were analyzed. Outcomes assessed included length of stay (LOS), discharge disposition, quality-adjusted life years (QALY), surgical-site infection (SSI), total cost, readmission within 30 days, and emergency department (ED) evaluation within 30 days. Results: Amongst the study population, 936 were braced and 44 were not braced. There was no difference between the braced and unbraced cohorts regarding LOS (P = .106), discharge disposition (P = .898), 30-day readmission (P = .434), and 30-day ED evaluation (P = 1.000). There was also no difference in total cost (P = .230) or QALY gain (P = .740). The results indicate a significantly lower likelihood of SSI in the braced population (1.50% versus 6.82%, odds ratio = 0.208, 95% confidence interval = 0.057-0.751, P = .037). There was no difference in relevant comorbidities (P = .259-1.000), although the braced cohort was older than the unbraced cohort (63 versus 56 y, P = .003). Conclusion: Bracing following multilevel posterior lumbar fixation does not alter short-term postoperative course or reduce the risk for early adverse events. Cost analysis show no difference in direct costs between the 2 treatment approaches. Short-term data suggest that removal of bracing from the postoperative regimen for PLF will not result in increased adverse outcomes

Recent advances in understanding and measurement of mercury in the environment: Terrestrial Hg cycling

This review documents recent advances in terrestrial mercury cycling. Terrestrial mercury (Hg) research has matured in some areas, and is developing rapidly in others. We summarize the state of the science circa 2010 as a starting point, and then present the advances during the last decade in three areas: land use, sulfate deposition, and climate change. The advances are presented in the framework of three Hg "gateways" to the terrestrial environment: inputs from the atmosphere, uptake in food, and run off with surface water. Among the most notable advances:The Arctic has emerged as a hotbed of Hg cycling, with high stream fluxes and large stores of Hg poised for release from permafrost with rapid high-latitude warming.The bi-directional exchange of Hg between the atmosphere and terrestrial surfaces is better understood, thanks largely to interpretation from Hg isotopes; the latest estimates place land surface Hg re-emission lower than previously thought.Artisanal gold mining is now thought responsible for over half the global stream flux of Hg.There is evidence that decreasing inputs ofHg to ecosystems may bring recovery sooner than expected, despite large ecosystem stores of legacy Hg.Freshly deposited Hg is more likely than stored Hg to methylate and be incorporated in rice.Topography and hydrological connectivity have emerged as master variables for explaining the disparate response of THg and MeHg to forest harvest and other land disturbance.These and other advances reported here are of value in evaluating the effectiveness of theMinamata Convention on reducing environmental Hg exposure to humans and wildlife. (C) 2020 The Authors. Published by Elsevier B.V

Molecular and atomic gas in the Local Group galaxy M 33

We present high resolution large scale observations of the molecular and atomic gas in the Local Group Galaxy M33. The observations were carried out using the HERA at the 30m IRAM telescope in the CO(2-1) line achieving a resolution of 12"x2.6 km/s, enabling individual GMCs to be resolved. The observed region mainly along the major axis out to a radius of 8.5 kpc, and covers the strip observed with HIFI/PACS Spectrometers as part of the HERM33ES Herschel key program. The achieved sensitivity in main beam temperature is 20-50 mK at 2.6 km/s velocity resolution. The CO(2-1) luminosity of the observed region is 1.7\pm0.1x10^7 Kkm/s pc^2, corresponding to H2 masses of 1.9x10^8 Msun (including He), calculated with a NH2/ICO twice the Galactic value due to the half-solar metallicity of M33. HI 21 cm VLA archive observations were reduced and the mosaic was imaged and cleaned using the multi-scale task in CASA, yielding a series of datacubes with resolutions ranging from 5" to 25". The HI mass within a radius of 8.5 kpc is estimated to be 1.4x10^9 Msun. The azimuthally averaged CO surface brightness decreases exponentially with a scale length of 1.9\pm0.1 kpc whereas the atomic gas surface density is constant at Sigma_HI=6\pm2 Msun/pc^2 deprojected to face-on. The central kiloparsec H_2 surface density is Sigma_H2=8.5\pm0.2 Msun/pc^2. The star formation rate per unit molecular gas (SF Efficiency, the rate of transformation of molecular gas into stars), as traced by the ratio of CO to Halpha and FIR brightness, is constant with radius. The SFE appears 2-4 times greater than of large spiral galaxies. A morphological comparison of molecular and atomic gas with tracers of star formation shows good agreement between these maps both in terms of peaks and holes. A few exceptions are noted. Several spectra, including those of a molecular cloud situated more than 8 kpc from the galaxy center, are presented.Comment: Accepted for publication in A&A. Higher resolution version available at : http://www.obs.u-bordeaux1.fr/radio/gratier/M33_CO_HI_accepted.pd

Optimized high gradient magnetic separation for isolation of Plasmodium-infected red blood cells

<p>Abstract</p> <p>Background</p> <p>Highly purified infected red blood cells (irbc), or highly synchronized parasite cultures, are regularly required in malaria research. Conventional isolation and synchronization rely on density and osmotic fragility of irbc, respectively. High gradient magnetic separation (HGMS) offers an alternative based on intrinsic magnetic properties of irbc, avoiding exposure to chemicals and osmotic stress. Successful HGMS concentration in malaria research was previously reported using polymer coated columns, while HGMS depletion has not been described yet. This study presents a new approach to both HGMS concentration and depletion in malaria research, rendering polymer coating unnecessary.</p> <p>Methods</p> <p>A dipole magnet generating a strong homogenous field was custom assembled. Polypropylene syringes were fitted with one-way stopcocks and filled with stainless steel wool. Rbc from <it>Plasmodium falciparum </it>cultures were resuspended in density and viscosity optimized HGMS buffers and HGMS processed. Purification and depletion results were analysed by flow cytometer and light microscopy. Viability was evaluated by calculating the infection rate after re-culturing of isolates.</p> <p>Results</p> <p>In HGMS concentration, purity of irbc isolates from asynchronous cultures consistently ranged from 94.8% to 98.4% (mean 95.7%). With further optimization, over 90% of isolated irbc contained segmented schizonts. Processing time was less than 45 min. Reinfection rates ranged from 21.0% to 56.4%. In HGMS depletion, results were comparable to treatment with sorbitol, as demonstrated by essentially identical development of cultures.</p> <p>Conclusion</p> <p>The novel HGMS concentration procedure achieves high purities of segmented stage irbc from standard asynchronous cultures, and is the first HGMS depletion alternative to sorbitol lysis. It represents a simple and highly efficient alternative to conventional irbc concentration and synchronization methods.</p

Stellar Encounters with the Beta Pictoris Planetesimal System

We use data from the Hipparcos Catalog and the Barbier-Brossat & Figon (2000) catalog of stellar radial velocities to test the hypothesis that the Beta Pic planetesimal disk was disrupted by a close stellar encounter. We trace the space motions of 21,497 stars and discover 18 that have passed within 5 pc of Beta Pic in the past 1 Myr. Beta Pic's closest encounter is with the K2III star HIP 27628 (0.6 pc), but dynamically the most important encounter is with the F7V star HIP 23693 (0.9 pc). We calculate the velocity and eccentricity changes induced by the 18 perturbations and conclude that they are dynamically significant if planetesimals exist in a Beta Pic Oort cloud. We provide a first-order estimate for the evolutionary state of a Beta Pic Oort cloud and conclude that the primary role of these stellar perturbations would be to help build a comet cloud rather than destroy a pre-existing structure. The stellar sample is 20% complete and motivates future work to identify less common close interactions that would significantly modify the observed circumstellar disk. For future radial velocity study we identify six stars in the Hipparcos Catalog that may have approached Beta Pic to within 0.1 pc and therefore remain as candidate disk perturbers.Comment: 23 pages, 5 figures, Accepted for publication in Ap

A 50-year record of NOx and SO2 sources in precipitation in the Northern Rocky Mountains, USA

Ice-core samples from Upper Fremont Glacier (UFG), Wyoming, were used as proxy records for the chemical composition of atmospheric deposition. Results of analysis of the ice-core samples for stable isotopes of nitrogen (δ15N, ) and sulfur (δ34S, ), as well as and deposition rates from the late-1940s thru the early-1990s, were used to enhance and extend existing National Atmospheric Deposition Program/National Trends Network (NADP/NTN) data in western Wyoming. The most enriched δ34S value in the UFG ice-core samples coincided with snow deposited during the 1980 eruption of Mt. St. Helens, Washington. The remaining δ34S values were similar to the isotopic composition of coal from southern Wyoming. The δ15N values in ice-core samples representing a similar period of snow deposition were negative, ranging from -5.9 to -3.2 ‰ and all fall within the δ15N values expected from vehicle emissions. Ice-core nitrate and sulfate deposition data reflect the sharply increasing U.S. emissions data from 1950 to the mid-1970s

Experiences with array-based sequence capture; toward clinical applications

Although sequencing of a human genome gradually becomes an option, zooming in on the region of interest remains attractive and cost saving. We performed array-based sequence capture using 385K Roche NimbleGen, Inc. arrays to zoom in on the protein-coding and immediate intron-flanking sequences of 112 genes, potentially involved in mental retardation and congenital malformation. Captured material was sequenced using Illumina technology. A data analysis pipeline was built that detects sequence variants, positions them in relation to the gene, checks for presence in databases (eg, db single-nucleotide polymorphism (SNP)) and predicts the potential consequences at the level of RNA splicing and protein translation. In the samples analyzed, all known variants were reliably detected, including pathogenic variants from control cases and SNPs derived from array experiments. Although overall coverage varied considerably, it was reproducible per region and facilitated the detection of large deletions and duplications (copy number variations), including a partial deletion in the B3GALTL gene from a patient sample. For ultimate diagnostic application, overall results need to be improved. Future arrays should contain probes from both DNA strands, and to obtain a more even coverage, one could add fewer probes from densely and more probes from sparsely covered regions