Why phosphoproteomics is still a challenge

Despite continuous improvements phosphoproteomics still faces challenges that are often neglected, e.g. partially poor recovery of phosphopeptide enrichment, assessment of phosphorylation stoichiometry, label-free quantification, poor behavior during chromatography, and general limitations of peptide-centric proteomics. Here we critically discuss current limitations that need consideration in both qualitative and quantitative studies

A large stellar evolution database for population synthesis studies. II. Stellar models and isochrones for an alpha-enhanced metal distribution

[Abridged] We present a large, new set of stellar evolution models and isochrones for an alpha-enhanced metal distribution typical of Galactic halo and bulge stars; it represents a homogeneous extension of our stellar model library for a distribution already presented in Pietrinferni et al.(2004). The effect of the alpha-element enhancement has been properly taken into account in the nuclear network, opacity, equation of state and, for the first time, the bolometric corrections, and color transformations. This allows us to avoid the inconsistent use - common to all alpha-enhanced model libraries currently available - of scaled-solar bolometric corrections and color transformations for alpha-enhanced models and isochrones. We show how bolometric corrections to magnitudes obtained for the U,B portion of stellar spectra for T_{eff}<=6500K, are significantly affected by the metal mixture, especially at the higher metallicities. We also provide complete sets of evolutionary models for low-mass, He-burning stellar structures covering the whole metallicity range, to enable synthetic horizontal branch simulations. We compare our database with several widely used stellar model libraries from different authors, as well as with various observed color magnitude and color-color diagrams (Johnson-Cousins BVI and near infrared magnitudes, Stromgren colors) of Galactic field stars and globular clusters. We also test our isochrones comparing integrated optical colors and Surface Brightness Fluctuation magnitudes with selected globular cluster data. We find a general satisfactory agreement with the empirical constraints.Comment: 46 pages, 20 figures, ApJ in press, the whole database presented in this paper can be foud at http://www.te.astro.it/BASTI/index.ph

Dehumidification over Tropical Continents Reduces Climate Sensitivity and Inhibits Snowball Earth Initiation

Thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Geology or Earth and Environmental Sciences, Department of Earth and Environmental SciencesThe enigmatic Neoproterozoic geological record suggests the potential for a fully glaciated “Snowball Earth.” Low-latitude continental position has been invoked as a potential Snowball Earth trigger by raising surface albedo and reducing atmospheric CO2 concentrations through increased silicate weathering. Herein, climate response to reduction of total solar irradiance (TSI) is tested using four different land configurations (aquaplanet, modern, Neoproterozoic, and low latitude supercontinent) with uniform topography in the NCAR Community Atmosphere Model (CAM, version 3.1) general circulation model with a mixed-layer ocean. Despite a lower surface albedo at 100% TSI, the threshold for global glaciation decreases from 92% TSI in the aquaplanet configuration to 85% TSI with a low-latitude supercontinent. The difference in thresholds is principally due to the sensitivity of total specific humidity and therefore greenhouse forcing to reductions in TSI. Dehumidification of the troposphere over large tropical continents decreases greenhouse forcing and also increases direct heating by decreasing cloud cover. Continental heating intensifies the Walker circulation and the transport of dry air over the ocean, enhancing surface evaporation and marine tropospheric humidification, maintaining a high specific humidity and greenhouse effect over the ocean. Topography also provides an important control on Snowball Earth initiation. Modern topography in the modern continental arrangement lowers the initiation threshold by up to 2% TSI relative to a modern continental arrangement without topography. In the absence of potential silicate weathering feedbacks, large tropical landmasses raise the barrier to initiation of Snowball events. More generally, these simulations demonstrate the substantial influence of geography on climate sensitivity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98092/1/Fiorella_Rich_MS_2012.pdf1

Stable Water Isotopes Reveal Effects of Intermediate Disturbance and Canopy Structure on Forest Water Cycling

Forests play an integral role in the terrestrial water cycle and link exchanges of water between the land surface and the atmosphere. To examine the effects of an intermediate disturbance on forest water cycling, we compared vertical profiles of stable water vapor isotopes in two closely located forest sites in northern lower Michigan. At one site, all canopy‐dominant early successional species were stem girdled to induce mortality and accelerate senescence. At both sites, we measured the isotopic composition of atmospheric water vapor at six heights during three seasons (spring, summer, and fall) and paired vertical isotope profiles with local meteorology and sap flux. Disturbance had a substantial impact on local water cycling. The undisturbed canopy was moister, retained more transpired vapor, and at times was poorly mixed with the free atmosphere above the canopy. Differences between the disturbed and undisturbed sites were most pronounced in the summer when transpiration was high. Differences in forest structure at the two sites also led to more isotopically stratified vapor within the undisturbed canopy. Our findings suggest that intermediate disturbance may increase mixing between the surface layer and above‐canopy atmosphere and alter ecosystem‐atmosphere gas exchange.Plain Language SummaryForests play an important role in the climate system and link water fluxes between the land surface and the atmosphere. Here we compare water vapor isotopes in two adjacent forest sites in the northern lower peninsula of Michigan to understand the effects of intermediate disturbance and canopy structure on forest water cycling. One site is dominated by aspen and birch and has a thick, closed canopy. All of the aspen and birch were killed at the second site. As a result, the disturbed site has a more open‐canopy structure. From our comparison, we found that both the species of tree and the spacing around trees are important controls on forest water cycling. With more space between trees, air mixes more freely into the canopy, which dries the forest air. Alternatively, air may be poorly mixed within and above thick, closed canopies.Key PointsIntermediate disturbance can change the contribution of entrained, evaporated, and transpired water vapor to forest canopiesCanopy gaps increase hydrologic mixing between the surface layer and the free atmosphereThe assumption of a well‐mixed canopy atmosphere may be violated in the case of thick, homogeneous forest canopiesPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152563/1/jgrg21482_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152563/2/jgrg21482.pd

Synthetic Lick Indices and Detection of α-enhanced Stars. III. F, G, and K Stars with [Fe/H] > 0.00

A sample of 119 F, G, and K solar neighborhood stars, selected under the condition [Fe/H] > 0.00, is investigated in order to detect which of them, if any, present α-enhanced characteristics. According to the kinematics, the sample represents stars of the thin-disk component of the Galaxy. The search of α-enhanced characteristics is performed by adopting an already tested procedure that does not require previous knowledge of the stellar main atmospheric parameters. The analysis is based on the comparison of spectral indices in the Lick IDS system, coming from different observational data sets, with synthetic ones computed with solar-scaled abundances and with α-element enhancement. The main result of the analysis is the extreme paucity (likely just one in 119) of α-enhanced stars in our sample, thus suggesting [α/Fe] = 0.0 for thin-disk stars with [Fe/H] > 0.00. This result, which is in agreement with the standard evolutionary picture of the disk of the Galaxy, is compared with recent results from high-resolution analysis reported in the literature. The role of the atmospheric parameter assumptions in the analysis of high-resolution spectroscopic data is discussed, and a possible explanation of discrepant results about α-enhancement for stars with [Fe/H] > 0.00 is presented

New laboratory predictive tools in deep neck space infections

Introduction. Deep neck space infections (DNSIs) are a group of infective suppurative dis-eases involving deep neck spaces and cervical fascia. Necrotising and septic evolutions are rare, but severe complications can dramatically affect the prognosis and should be promptly managed. Clinical examination often has low sensitivity, although instrumental diagnosis may delay te treatment. We investigated two laboratory tools, LRINEC (Laboratory Risk Indicator for the Necrotizing fasciitis) and NLR (neutrophil to lymphocyte ratio), in the expectation to find a rapidly available predictive indicator that may help in distinguishing necrotising complications and/or systemic septic involvement. Methods. A retrospective observational cohort study was performed on 118 patients who had underwent surgical treatment for DNSIs at our Surgical Unit. LRINEC, NLR and the product LRINEC x NLR were calculated. Results. Statistical analysis showed that these scores may have utility in rapidly predicting the risk of necrotising fasciitis and systemic involvement at an early diagnostic stage. Conclusions. Further studies with a larger cohort may be necessary in order to increase the sensitivity and specificity

An isotopic approach to partition evapotranspiration in a mixed deciduous forest

Transpiration (T) is perhaps the largest fluxes of water from the land surface to the atmosphere and is susceptible to changes in climate, land use and vegetation structure. However, predictions of future transpiration fluxes vary widely and are poorly constrained. Stable water isotopes can help expand our understanding of land–atmosphere water fluxes but are limited by a lack of observations and a poor understanding of how the isotopic composition of transpired vapour (δT) varies. Here, we present isotopic data of water vapour, terrestrial water and plant water from a deciduous forest to understand how vegetation affects water budgets and land–atmosphere water fluxes. We measured subdiurnal variations of δ18OT from three tree species and used water isotopes to partition T from evapotranspiration (ET) to quantify the role of vegetation in the local water cycle. We find that δ18OT deviated from isotopic steady‐state during the day but find no species‐specific patterns. The ratio of T to ET varied from 53% to 61% and was generally invariant during the day, indicating that diurnal evaporation and transpiration fluxes respond to similar atmospheric and micrometeorological conditions at this site. Finally, we compared the isotope‐inferred ratio of T to ET with results from another ET partitioning approach that uses eddy covariance and sap flux data. We find broad midday agreement between these two partitioning techniques, in particular, the absence of a diurnal cycle, which should encourage future ecohydrological isotope studies. Isotope‐inferred estimates of transpiration can inform land surface models and improve our understanding of land–atmosphere water fluxes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162787/2/eco2229.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162787/1/eco2229_am.pd

A case of severe dermatitis in a patient with Polycythemia Vera during cytoreductive therapy

Polycythemia Vera (PV) is a Philadelphia-negative chronic myeloproliferative neoplasm (MPN) mainly characterized by erythrocytosis. In this report we describe a case of severe cutaneous toxicity in patients with PV treated with hydroxyurea. A 72-year-old woman diagnosed with PV with V617F mutation of JAK2 performed more than 10 years before and treated with hydroxyurea plus phlebotomies and low-dose ASA for about 7 years addressed our center for the appearance of serious dermatitis at the face symptomatic for severe itch. The patient underwent a dermatology visit with diagnosis of desquamative dermatitis due to iatrogenic cause related to the use of hydroxyurea. HU was stopped for a month with no improvement after a month of wash-out. Ruxolitinib was prescribed at a dose of 20 mg per day, in order to control hypercytosis and considering the severe intolerance to hydroxyurea. Ruxolitinib allowed not only to reduce the haematocrit, reaching the target value of 45%, and control thrombocytosis, but also to switch off the severe itch and to completely resolve skin toxicity

Spatiotemporal variability of modern precipitation δ18O in the central Andes and implications for paleoclimate and paleoaltimetry estimates

Understanding the patterns of rainfall isotopic composition in the central Andes is hindered by sparse observations. Despite limited observational data, stable isotope tracers have been commonly used to constrain modern‐to‐ancient Andean atmospheric processes, as well as to reconstruct paleoclimate and paleoaltimetry histories. Here, we present isotopic compositions of precipitation (δ18Op and δDp) from 11 micrometeorological stations located throughout the Bolivian Altiplano and along its eastern flank at ~21.5°S. We collected and isotopically analyzed 293 monthly bulk precipitation samples (August 2008 to April 2013). δ18Op values ranged from −28.0‰ to 9.6‰, with prominent seasonal cycles expressed at all stations. We observed a strong relationship between the δ18Op and elevation, though it varies widely in time and space. Constraints on air sourcing estimated from atmospheric back trajectory calculations indicate that continental‐scale climate dynamics control the interannual variability in δ18Op, with upwind precipitation anomalies having the largest effect. The impact of precipitation anomalies in distant air source regions to the central Andes is in turn modulated by the Bolivian High. The importance of the Bolivian High is most clearly observed on the southern Bolivian Altiplano. However, monthly variability among Altiplano stations can exceed 10‰ in δ18Op on the plateau and cannot be explained by elevation or source variability, indicating a nontrivial role for local scale effects on short timescales. The strong influence of atmospheric circulation on central Andean δ18Op requires that paleoclimate and paleoaltimetry studies consider the role of South American atmospheric paleocirculation in their interpretation of stable isotopic values as proxies.Key PointsFive‐year record of central Andes precipitation isotopic compositionPrecipitation isotopes are elevation dependent, but vary in space and timePrecipitation isotope variability is related to large‐scale climate dynamicsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111974/1/jgrd52161.pd