675 research outputs found

    Radar-aeolian roughness project

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    The objective is to establish an empirical relationship between measurements of radar, aeolian, and surface roughness on a variety of natural surfaces and to understand the underlying physical causes. This relationship will form the basis for developing a predictive equation to derive aeolian roughness from radar backscatter. Results are given from investigations carried out in 1989 on the principal elements of the project, with separate sections on field studies, radar data analysis, laboratory simulations, and development of theory for planetary applications

    Delayed diagnosis of cystic fibrosis associated with R117H on a background of 7T polythymidine tract at intron 8

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    AbstractWe report late diagnoses of cystic fibrosis (CF) in two men aged 61 and 65 years. At the time of presentation, both patients had significant pulmonary disease. In each case two CFTR gene mutations were identified, including R117H on a background of a poly T genotype of 7T/9T. Patients with two identified CFTR mutations which include the R117H/7T anomaly should be followed up routinely as they remain susceptible to severe lung disease

    The Role of Racial Identity and Implicit Racial Bias in Self-Reported Racial Discrimination: Implications for Depression Among African American Men

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    Racial discrimination is conceptualized as a psychosocial stressor that has negative implications for mental health. However, factors related to racial identity may influence whether negative experiences are interpreted as instances of racial discrimination and subsequently reported as such in survey instruments, particularly given the ambiguous nature of contemporary racism. Along these lines, dimensions of racial identity may moderate associations between racial discrimination and mental health outcomes. This study examined relationships between racial discrimination, racial identity, implicit racial bias, and depressive symptoms among African American men between 30 and 50 years of age (n = 95). Higher racial centrality was associated with greater reports of racial discrimination, while greater implicit anti-Black bias was associated with lower reports of racial discrimination. In models predicting elevated depressive symptoms, holding greater implicit anti-Black bias in tandem with reporting lower racial discrimination was associated with the highest risk. Results suggest that unconscious as well as conscious processes related to racial identity are important to consider in measuring racial discrimination, and should be integrated in studies of racial discrimination and mental health

    Future Dominance by Quaking Aspen Expected Following Short-Interval, Compounded Disturbance Interaction

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    The spatial overlap of multiple ecological disturbances in close succession has the capacity to alter trajectories of ecosystem recovery. Widespread bark beetle outbreaks and wildfire have affected many forests in western North America in the past two decades in areas of important habitat for native ungulates. Bark beetle outbreaks prior to fire may deplete seed supply of the host species, and differences in fire‐related regeneration strategies among species may shift the species composition and structure of the initial forest trajectory. Subsequent browsing of postfire tree regeneration by large ungulates, such as elk (Cervus canadensis), may limit the capacity for regeneration to grow above the browse zone to form the next forest canopy. Five stand‐replacing wildfires burned ~60,000 ha of subalpine forest that had previously been affected by severe ( \u3e90% mortality) outbreaks of spruce beetle (SB, Dendroctonus rufipennis) in Engelmann spruce (Picea engelmannii) in 2012–2013 in southwestern Colorado. Here we examine the drivers of variability in abundance of newly established conifer tree seedlings [spruce and subalpine fir (Abies lasiocarpa)] and resprouts of quaking aspen (Populus tremuloides) following the short‐interval sequence of SB outbreaks and wildfire (2–8 yr between SB outbreak and fire) at sites where we previously reconstructed severities of SB and fire. We then examine the implications of ungulate browsing for forest recovery. We found that abundances of postfire spruce seedling establishment decreased substantially in areas of severe SB outbreak. Prolific aspen resprouting in stands with live aspen prior to fire will favor an initial postfire forest trajectory dominated by aspen. However, preferential browsing of postfire aspen resprouts by ungulates will likely slow the rate of canopy recovery but browsing is unlikely to alter the species composition of the future forest canopy. Collectively, our results show that SB outbreak prior to fire increases the vulnerability of spruce–fir forests to shifts in forest type (conifer to aspen) and physiognomic community type (conifer forest to non‐forest). By identifying where compounded disturbance interactions are likely to limit recovery of forests or tree species, our findings are useful for developing adaptive management strategies in the context of warming climate and shifting disturbance regimes

    Total and Active Rabbit Antithymocyte Globulin (rATG;Thymoglobulin®) Pharmacokinetics in Pediatric Patients Undergoing Unrelated Donor Bone Marrow Transplantation

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    AbstractRabbit antithymocyte globulin (rATG; Thymoglobulin®) is currently used to prevent or treat graft-versus-host disease (GVHD) during hematopoietic stem cell transplantation (HSCT). The dose and schedule of rATG as part of the preparative regimen for unrelated donor (URD) bone marrow transplantation (BMT) have not been optimized in pediatric patients. We conducted a prospective study of 13 pediatric patients with hematologic malignancies undergoing URD BMT at St. Jude Children's Research Hospital from October 2003 to March 2005, to determine the pharmacokinetics and toxicities of active and total rATG. The conditioning regimen comprised total body irradiation (TBI), thiotepa, and cyclophosphamide (Cy); cyclosporine (CsA) and methotrexate (MTX) were administered as GVHD prophylaxis. Patients received a total dose of 10 mg/kg rATG, and serial blood samples were assayed for total rATG by enzyme linked immunosorbent assay (ELISA) and active rATG by florescein activated cell sorting (FACS). We found that our weight-based dosing regimen for rATG was effective and well tolerated by patients. The half-lives of total and active rATG were comparable to those from previous studies, and despite high doses our patients had low maximum concentrations of active and total rATG. There were no occurrences of grade iii-iv GVHD even in patients having low peak rATG levels, and the overall incidence of grade II GVHD was only 15%. None of the patients had serious infections following transplantation. These data support the use of a 10 mg/kg dose of rATG in children with hematologic malignancies because it can be administered without increasing the risk of graft rejection, or serious infection in pediatric patients with a low rate of GVHD. These conclusions may not apply to patients with nonmalignant disorders

    Canine respiratory coronavirus employs caveolin-1-mediated pathway for internalization to HRT-18G cells

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    Canine respiratory coronavirus (CRCoV), identified in 2003, is a member of the Coronaviridae family. The virus is a betacoronavirus and a close relative of human coronavirus OC43 and bovine coronavirus. Here, we examined entry of CRCoV into human rectal tumor cells (HRT-18G cell line) by analyzing co-localization of single virus particles with cellular markers in the presence or absence of chemical inhibitors of pathways potentially involved in virus entry. We also targeted these pathways using siRNA. The results show that the virus hijacks caveolin-dependent endocytosis to enter cells via endocytic internalization

    Till death (or an intruder) do us part: intrasexual-competition in a monogamous Primate

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    Polygynous animals are often highly dimorphic, and show large sex-differences in the degree of intra-sexual competition and aggression, which is associated with biased operational sex ratios (OSR). For socially monogamous, sexually monomorphic species, this relationship is less clear. Among mammals, pair-living has sometimes been assumed to imply equal OSR and low frequency, low intensity intra-sexual competition; even when high rates of intra-sexual competition and selection, in both sexes, have been theoretically predicted and described for various taxa. Owl monkeys are one of a few socially monogamous primates. Using long-term demographic and morphological data from 18 groups, we show that male and female owl monkeys experience intense intra-sexual competition and aggression from solitary floaters. Pair-mates are regularly replaced by intruding floaters (27 female and 23 male replacements in 149 group-years), with negative effects on the reproductive success of both partners. Individuals with only one partner during their life produced 25% more offspring per decade of tenure than those with two or more partners. The termination of the pair-bond is initiated by the floater, and sometimes has fatal consequences for the expelled adult. The existence of floaters and the sporadic, but intense aggression between them and residents suggest that it can be misleading to assume an equal OSR in socially monogamous species based solely on group composition. Instead, we suggest that sexual selection models must assume not equal, but flexible, context-specific, OSR in monogamous species.Wenner-Gren Foundation, L.S.B. Leakey Foundation, the National Geographic Society, National Science Foundation (BCS- 0621020), the University of Pennsylvania Research Foundation and the Zoological Society of San Diego, German Science Foundation (HU 1746-2/1

    Monoubiquitination of syntaxin 3 leads to retrieval from the basolateral plasma membrane and facilitates cargo recruitment to exosomes

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    Syntaxin 3 (Stx3), a SNARE protein located and functioning at the apical plasma membrane of epithelial cells, is required for epithelial polarity. A fraction of Stx3 is localized to late endosomes/lysosomes, although how it traffics there and its function in these organelles is unknown. Here we report that Stx3 undergoes monoubiquitination in a conserved polybasic domain. Stx3 present at the basolateral—but not the apical—plasma membrane is rapidly endocytosed, targeted to endosomes, internalized into intraluminal vesicles (ILVs), and excreted in exosomes. A nonubiquitinatable mutant of Stx3 (Stx3-5R) fails to enter this pathway and leads to the inability of the apical exosomal cargo protein GPRC5B to enter the ILV/exosomal pathway. This suggests that ubiquitination of Stx3 leads to removal from the basolateral membrane to achieve apical polarity, that Stx3 plays a role in the recruitment of cargo to exosomes, and that the Stx3-5R mutant acts as a dominant-negative inhibitor. Human cytomegalovirus (HCMV) acquires its membrane in an intracellular compartment and we show that Stx3-5R strongly reduces the number of excreted infectious viral particles. Altogether these results suggest that Stx3 functions in the transport of specific proteins to apical exosomes and that HCMV exploits this pathway for virion excretion
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