Observations and comparisons of cloud microphysical properties in spring and summertime Arctic stratocumulus clouds during the ACCACIA campaign

Measurements from four case studies in spring and summer-time Arctic stratocumulus clouds during the Aerosol-Cloud Coupling And Climate Interactions in the Arctic (ACCACIA) campaign are presented. We compare microphysics observations between cases and with previous measurements made in the Arctic and Antarctic. During ACCACIA, stratocumulus clouds were observed to consist of liquid at cloud tops, often at distinct temperature inversions. The cloud top regions precipitated low concentrations of ice into the cloud below. During the spring cases median ice number concentrations (~ 0.5 L−1) were found to be lower by about a factor of 5 than observations from the summer campaign (~ 3 L−1). Cloud layers in the summer spanned a warmer temperature regime than in the spring and enhancement of ice concentrations in these cases was found to be due to secondary ice production through the Hallett–Mossop (H–M) process. Aerosol concentrations during spring ranged from ~ 300–400 cm−3 in one case to lower values of ~ 50–100 cm−3 in the other. The concentration of aerosol with sizes Dp > 0.5 μm was used in a primary ice nucleus (IN) prediction scheme (DeMott et al., 2010). Predicted IN values varied depending on aerosol measurement periods but were generally greater than maximum observed median values of ice crystal concentrations in the spring cases, and less than the observed ice concentrations in the summer due to the influence of secondary ice production. Comparison with recent cloud observations in the Antarctic summer (Grosvenor et al., 2012), reveals lower ice concentrations in Antarctic clouds in comparable seasons. An enhancement of ice crystal number concentrations (when compared with predicted IN numbers) was also found in Antarctic stratocumulus clouds spanning the H–M temperature zone; however, concentrations were about an order of magnitude lower than those observed in the Arctic summer cases but were similar to the peak values observed in the colder Arctic spring cases, where the H–M mechanism did not operate

GABAB receptors regulate extrasynaptic GABAA receptors

Tonic inhibitory GABAA receptor-mediated currents are observed in numerous cell types in the CNS, including thalamocortical neurons of the ventrobasal thalamus, dentate gyrus granule cells, and cerebellar granule cells. Here we show that in rat brain slices, activation of postsynaptic GABAB receptors enhances the magnitude of the tonic GABAA current recorded in these cell types via a pathway involving Gi/o G proteins, adenylate cyclase, and cAMP-dependent protein kinase. Using a combination of pharmacology and knockout mice, we show that this pathway is independent of potassium channels or GABA transporters. Furthermore, the enhancement in tonic current is sufficient to significantly alter the excitability of thalamocortical neurons. These results demonstrate for the first time a postsynaptic crosstalk between GABAB and GABAA receptors.peer-reviewe

Robust Estimators in Generalized Pareto Models

This paper deals with optimally-robust parameter estimation in generalized Pareto distributions (GPDs). These arise naturally in many situations where one is interested in the behavior of extreme events as motivated by the Pickands-Balkema-de Haan extreme value theorem (PBHT). The application we have in mind is calculation of the regulatory capital required by Basel II for a bank to cover operational risk. In this context the tail behavior of the underlying distribution is crucial. This is where extreme value theory enters, suggesting to estimate these high quantiles parameterically using, e.g. GPDs. Robust statistics in this context offers procedures bounding the influence of single observations, so provides reliable inference in the presence of moderate deviations from the distributional model assumptions, respectively from the mechanisms underlying the PBHT.Comment: 26pages, 6 figure

U–Pb zircon-rutile dating of the Llangynog Inlier, Wales: constraints on an Ediacaran shallow marine fossil assemblage from East Avalonia

The Llangynog Inlier of south Wales contains an assemblage of Ediacaran macrofossils from a shallow-marine environment, including discoidal morphs of Aspidella and rare examples of Hiemalora, Palaeopascichnus and Yelovichnus. These are taxa found in other sites in the Avalonian microcontinent (e.g. Charnwood Forest and eastern Newfoundland) and in the younger White Sea Ediacaran assemblages. As the Charnwood fossils reflect a deep-water environment, and no macrofossils have been found in the Ediacaran rocks of the Long Mynd, the fossils of the Llangynog Inlier represent a unique glimpse of shallow marine life in southern Britain (East Avalonia). However, the lack of absolute age constraints has hampered direct comparison with other assemblages. Here, we report in-situ zircon and rutile U–Pb dates from a rhyolitic ash-flow layer of the Coed Cochion Volcaniclastic Member, Llangynog Inlier, which constrains the age of the fossiliferous strata. A weighted mean single grain zircon ID-TIMS U–Pb age of 564.09 ± 0.70 Ma is interpreted as the rhyolite's crystallisation age. This age is consistent with in-situ LA-ICPMS zircon and rutile U–Pb dating. The Llangynog age temporally correlates these fossils to dated horizons within East Avalonia at the Beacon Hill Formation, Charnwood (565.22 ± 0.89 Ma), and the Stretton Shale Formation, Long Mynd (566.6 ± 2.9 Ma). Correlations to West Avalonia include the time-equivalent Fermeuse Formation, St John’s Group, eastern Newfoundland (564.13 ± 0.65 Ma). The data presented here establish the biota of the Llangynog Inlier as a lateral equivalent to the similarly shallow marine, tidally influenced ecosystem of the upper Fermeuse Formation. Intra-terrane depositional environmental variability also affects what is preserved in Avalonian fossil sites. Further, time-constrained geochemical data reinforce the Llangynog Inlier's classification within the Wrekin Terrane

The impact of a chief planning officer on the administrative environment for planning

Institution-wide planning, to be effective, must have the support of key administrators. Presidents, vice-presidents, deans, and directors must feel that sufficient consensus can be reached on explicit goals to make comprehensive planning possible and worthwhile. While much has been written about the importance of CEO leadership in gaining broad support for planning, little has been said about the role of the chief planning officer in this regard. This paper, based on a national survey of administrators' views of planning, studies the relationship between having a chief planning officer and administrators' perceptions of campus planning. Its intended audience includes all those interested in institutional planning.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43608/1/11162_2004_Article_BF00991968.pd

Eine verbesserte fluorimetrische Cortisolbestimmung im Serum

Die fluorimetrische Methode zur Bestimmung von Serumcortisol wurde durch blasenfreie Füllung einer Spezialküvette mittels Pumpvorrichtung, durch Benützung eines Spectralfluorimeters, sowie Verlegung des Meßzeitpunktes (80 min) und durch optimale Anregung (464 nm) und Emissionsmessung (522 nm) verbessert. Empfindlichkeit (<1 µg Cortisol/100 ml), Richtigkeit, Genauigkeit, Reproduzierbarkeit von Tag zu Tag (VK=6–7%) und Störfaktoren der Methode werden angegeben. Mit dieser Methode wurden Normalberciche für die 9 Uhr-Nüchterncortisolwerte und die i.v. ACTH-Belastung ermittelt. Bei NNR-insuffizienten Patienten (M. Addison; Zustand nach Operation eines Hypophysentumors; total Adrenalektomierte) wurden i.v. ACTH-Belastungen durchgeführt, wobei sich bereits beim 9 Uhr-Nüchterncortisolwert eine diagnostisch gut brauchbare Trennung gegenüber dem Normalbereich ergab. Unter Dexamethasonsubstitution wurden bei NNR-Insuffizienz sehr niedrige Cortisolspiegel gemessen, was für die Spezifität der Methode spricht. Dic Bestimmung des 24 Std-Rhythmus der Cortisolwerte bei NNR-Insuffizienten zeigte, daß besonders in den frühen Morgenstunden im Vergleich zu Normalpersonen erniedrigte Cortisolspiegel bestehen. Daraus wird ein besserer Verteilungsvorschlag für die Cortisol-substitution abgeleitet.The fluorimetric determination of serum cortisol was improved 1. using a pumpdevice to fill a special microcuvette avoiding the development of small bubbles, 2. using a recording spectrofluorometer with optimal absorption (464 nm) and emission (522 nm), and 3. allowing for maximal fluorescence of cortisol (80 min). Sensitivity (<1 µg cortisol/100 ml), accuracy, precision and specificity of the method are reported. Normal values of 9.00 a.m. serum cortisol (9.7–32.0 µg/100 ml) and of values before and after ACTH infusion tests were determined. For adrenal insufficiency (Addisons disease, total adrenalectomy, or after hypophysectomy) the 9.00 a.m. values of serum cortisol were generally satisfactory for diagnosis. In partial adrenal insufficiency ACTH infusion tests had to be performed. Very low levels of serum cortisol (2–4 µg/100 ml) were obtained, when patients with adrenal insufficiency were substituted with dexamethasone for three days, proving the specificity of the method. Determination of circadian rhythms of serum cortisol in patients with adrenal insufficiency on cortisol substitutive therapy in divided doses demonstrated cortisol levels far below the normal values during the carly morning hours. This situation should be improved by dividing the cortisol dose as follows: 6 a.m.: 10 mg, 10 a.m.: 5 mg, 2 p.m.: 5 mg and 8 p.m. or later: 10 mg cortisol

Further evidence for the involvement of EFL1 in a Shwachman-Diamond-like syndrome and expansion of the phenotypic features.

Recent evidence has implicated EFL1 in a phenotype overlapping Shwachman-Diamond syndrome (SDS), with the functional interplay between EFL1 and the previously known causative gene SBDS accounting for the similarity in clinical features. Relatively little is known about the phenotypes associated with pathogenic variants in the EFL1 gene, but the initial indication was that phenotypes may be more severe, when compared with SDS. We report a pediatric patient who presented with a metaphyseal dysplasia and was found to have biallelic variants in EFL1 on reanalysis of trio whole-exome sequencing data. The variant had not been initially reported because of the research laboratory's focus on de novo variants. Subsequent phenotyping revealed variability in her manifestations. Although her metaphyseal abnormalities were more severe than in the original reported cohort with EFL1 variants, the bone marrow abnormalities were generally mild, and there was equivocal evidence for pancreatic insufficiency. Despite the limited number of reported patients, variants in EFL1 appear to cause a broader spectrum of symptoms that overlap with those seen in SDS. Our report adds to the evidence of EFL1 being associated with an SDS-like phenotype and provides information adding to our understanding of the phenotypic variability of this disorder. Our report also highlights the value of exome data reanalysis when a diagnosis is not initially apparent

Microtubules in Bacteria: Ancient Tubulins Build a Five-Protofilament Homolog of the Eukaryotic Cytoskeleton

Microtubules play crucial roles in cytokinesis, transport, and motility, and are therefore superb targets for anti-cancer drugs. All tubulins evolved from a common ancestor they share with the distantly related bacterial cell division protein FtsZ, but while eukaryotic tubulins evolved into highly conserved microtubule-forming heterodimers, bacterial FtsZ presumably continued to function as single homopolymeric protofilaments as it does today. Microtubules have not previously been found in bacteria, and we lack insight into their evolution from the tubulin/FtsZ ancestor. Using electron cryomicroscopy, here we show that the tubulin homologs BtubA and BtubB form microtubules in bacteria and suggest these be referred to as “bacterial microtubules” (bMTs). bMTs share important features with their eukaryotic counterparts, such as straight protofilaments and similar protofilament interactions. bMTs are composed of only five protofilaments, however, instead of the 13 typical in eukaryotes. These and other results suggest that rather than being derived from modern eukaryotic tubulin, BtubA and BtubB arose from early tubulin intermediates that formed small microtubules. Since we show that bacterial microtubules can be produced in abundance in vitro without chaperones, they should be useful tools for tubulin research and drug screening

Critical Perspective: Named Reactions Discovered and Developed by Women

Named organic reactions. As chemists, we’re all familiar with them: who can forget the Diels−Alder reaction? But how much do we know about the people behind the names? For example, can you identify a reaction named for a woman? How about a reaction discovered or developed by a woman but named for her male adviser? Our attempts to answer these simple questions started us on the journey that led to this Account. We introduce you to four reactions named for women and nine reactions discovered or developed by women. Using information obtained from the literature and, whenever possible, through interviews with the chemists themselves, their associates, and their advisers, we paint a more detailed picture of these remarkable women and their outstanding accomplishments. Some of the women you meet in this Account include Irma Goldberg, the only woman unambiguously recognized with her own named reaction. Gertrude Maud Robinson, the wife of Robert Robinson, who collaborated with him on several projects including the Piloty−Robinson pyrrole synthesis. Elizabeth Hardy, the Bryn Mawr graduate student who discovered the Cope rearrangement. Dorothee Felix, a critical member of Albert Eschenmoser’s research lab for over forty years who helped develop both the Eschenmoser−Claisen rearrangement and the Eschenmoser−Tanabe fragmentation. Jennifer Loebach, the University of Illinois undergraduate who was part of the team in Eric Jacobsen’s lab that discovered the Jacobsen−Katsuki epoxidation. Keiko Noda, a graduate student in Tsutomu Katsuki’s lab who also played a key role in the development of the Jacobsen−Katsuki epoxidation. Lydia McKinstry, a postdoc in Andrew Myers’s lab who helped develop the Myers asymmetric alkylation. Rosa Lockwood, a graduate student at Boston College whose sole publication is the discovery of the Nicholas reaction. Kaori Ando, a successful professor in Japan who helped develop the Roush asymmetric alkylation as a postdoc at MIT. Bianka Tchoubar, a critically important member of the organic chemistry community in France who developed the Tiffeneau−Demjanov rearrangement. The accomplishments of the women in this Account illustrate the key roles women have played in the discovery and development of reactions used daily by organic chemists around the world. These pioneering chemists represent the vanguard of women in the field, and we are confident that many more of the growing number of current and future female organic chemists will be recognized with their own named reactions

Quality Assessment and Data Analysis for microRNA Expression Arrays

MicroRNAs are small (∼22 nt) RNAs that regulate gene expression and play important roles in both normal and disease physiology. The use of microarrays for global characterization of microRNA expression is becoming increasingly popular and has the potential to be a widely used and valuable research tool. However, microarray profiling of microRNA expression raises a number of data analytic challenges that must be addressed in order to obtain reliable results. We introduce here a universal reference microRNA reagent set as well as a series of nonhuman spiked-in synthetic microRNA controls, and demonstrate their use for quality control and between-array normalization of microRNA expression data. We also introduce diagnostic plots designed to assess and compare various normalization methods. We anticipate that the reagents and analytic approach presented here will be useful for improving the reliability of microRNA microarray experiments