1,206 research outputs found

    Evapotranspiration of two vegetation communities in a high-elevation riparian meadow at Hart Prairie, Arizona

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    Hart Prairie, Arizona, has the largest Bebb willow (Salix bebbiana) community in the United States; however, greater than 95% of willows are older than 80 years and regeneration by seed is not occurring. This study examined the evapotranspiration of two herbaceous communities that dominate the Hart Prairie watershed: (1) a mixture of bracken fern (Pteridium aquilinum) and graminoids and (2) dominantly graminoids. Transpiration during premonsoon and postmonsoon dry periods of 2000, 2001, and 2002 was estimated for each community by the difference in volumetric soil-water content (0-30 cm soil depth) between replicated plots that were clipped of all vegetation and control, unclipped plots. Transpiration rates estimated under conditions of minimal soil drainage varied between 0.63 and 2.4 mm/d for the fern-graminoid community and 0.57 and 1.1 mm/d for the graminoid community over the study. The fern-graminoid community produced more biomass than the graminoid community in all years, but generally had lower transpiration rates. Severe drought in year 2002 reduced growth and transpiration of the fern-graminoid community more than the graminoid community. Evaporation rates were estimated by temporal changes in soil-water content in clipped plots during dry periods, and were 54 to 474% of transpiration rates estimated under conditions of minimal soil drainage because of the dry and windy conditions that occur at the study site. Based on this study and a study of transpiration of scattered trees invading the meadow, transpiration by the herbaceous understorey was higher than transpiration by trees during similar seasons

    Development of a Next-Generation NIL Library in Arabidopsis Thaliana for Dissecting Complex Traits

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    The identification of the loci and specific alleles underlying variation in quantitative traits is an important goal for evolutionary biologists and breeders. Despite major advancements in genomics technology, moving from QTL to causal alleles remains a major challenge in genetics research. Near-isogenic lines are the ideal raw material for QTL validation, refinement of QTL location and, ultimately, gene discovery. Results: In this study, a population of 75 Arabidopsis thaliana near-isogenic lines was developed from an existing recombinant inbred line (RIL) population derived from a cross between physiologically divergent accessions Kas-1 and Tsu-1. First, a novel algorithm was developed to utilize genome-wide marker data in selecting RILs fully isogenic to Kas-1 for a single chromosome. Seven such RILs were used in 2 generations of crossing to Tsu-1 to create BC1 seed. BC1 plants were genotyped with SSR markers so that lines could be selected that carried Kas-1 introgressions, resulting in a population carrying chromosomal introgressions spanning the genome. BC1 lines were genotyped with 48 genome-wide SSRs to identify lines with a targeted Kas-1 introgression and the fewest genomic introgressions elsewhere. 75 such lines were selected and genotyped at an additional 41 SNP loci and another 930 tags using 2b-RAD genotyping by sequencing. The final population carried an average of 1.35 homozygous and 2.49 heterozygous introgressions per line with average introgression sizes of 5.32 and 5.16 Mb, respectively. In a simple case study, we demonstrate the advantage of maintaining heterozygotes in our library whereby fine-mapping efforts are conducted simply by self-pollination. Crossovers in the heterozygous interval during this single selfing generation break the introgression into smaller, homozygous fragments (sub-NILs). Additionally, we utilize a homozygous NIL for validation of a QTL underlying stomatal conductance, a low heritability trait. Conclusions: The present results introduce a new and valuable resource to the Brassicaceae research community that enables rapid fine-mapping of candidate loci in parallel with QTL validation. These attributes along with dense marker coverage and genome-wide chromosomal introgressions make this population an ideal starting point for discovery of genes underlying important complex traits of agricultural and ecological significance.NSF DEB-1022196, DEB-0618302, DEB-0618347, IOS-09221457Integrative Biolog

    Nuclear small-subunit ribosomal RNA gene-based characterization, molecular phylogeny and PCR detection of the Neoparamoeba from western Long Island Sound lobster

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    Author Posting. © National Shellfisheries Association, 2005. This article is posted here by permission of National Shellfisheries Association for personal use, not for redistribution. The definitive version was published in Journal of Shellfish Research 24 (2005): 719-731, doi:10.2983/0730-8000(2005)24[719:NSRRGC]2.0.CO;2.Western Long Island Sound (LIS) lobsters collected by trawl surveys, lobstermen and coastal residents during 2000 to 2002 were identified histologically as infected with a parasome-containing amoeba. Primers to conserved SSU rRNA sequences of parasome-containing amoebae and their nonparasome-containing relatives were used to amplify overlapping SSU rRNA fragments of the presumptive parasite from gill, antenna, antennal gland and ventral nerve cord of infected lobsters. The consensus sequence constructed from these fragments had 98% or greater nucleotide sequence identity with SSU rRNA gene sequences of strains of Neoparamoeba pemaquidensis and associated with high confidence in distance- and parsimony-based phylogenetic analyses with strains of Neoparamoeba pemaquidensis and not members of the family Paramoebidae, e.g., Paramoeba eilhardi. Primers designed to SSU rRNA sequences of the lobster amoeba and other paramoebid/vexilliferid amoebae were used in a nested polymerase chain reaction (PCR) protocol to test DNA extracted from formalin-fixed paraffin-embedded tissues of lobsters collected during the 1999 die-off, when this amoeba initially was identified by light and electron microscopy and reported to be a paramoeba of the genera Paramoeba or Neoparamoeba (Mullen et al. 2004). All sequences amplified from 1999 lobsters, with the exception of one, had 98% to 99% identity to each other, and the 1999 PCR product consensus had 98% identity to Neoparamoeba pemaquidensis strains CCAP 1560/4 (AF371969.1) and 1560/5 (AF371970.1). Molecular characterization of the amoeba from western LIS lobsters by direct amplification circumvents a collective inability to culture the organism in vitro, provides insight into the molecular epidemiology of neoparamoebiasis in American lobster, and allows for PCR-based detection of infected lobsters for future research and diagnostics.Funding for this work was provided by the Connecticut Department of Environmental Protection under Long Island Sound Research Fund Grant No. CWF 333-R to S. Frasca; and by the Connecticut Sea Grant College Program, Grants No. LR/LR-4 to R. Gast and No. LR/LR-5 to P. Gillevet and C. O’Kelly, through the US Department of Commerce, National Oceanic and Atmospheric Administration (NOAA), Award NA16RG1364

    Augmenter of liver regeneration enhances the success rate of fetal pancreas transplantation in rodents

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    Background. Treatment of fetal pancreas (FP) isografts with insulin- like growth factor-I greatly improves the rate of conversion to euglycemia in diabetic rats. Complete knowledge of other factors that may facilitate the engraftment and function of FP in vivo is still embryonic. Augmenter of liver regeneration (ALR) is a newly described polypeptide growth factor found in weanling rat livers. ALR has trophic effects on regenerating liver. We studied the effects of in situ administration of this agent on FP isografts in rats. Methods. Streptozotocin-diabetic Lewis rats (blood glucose >300 mg/dl) received 16 FP isografts transplanted intramuscularly. ALR was delivered from day 1 through day 14, in doses of 40 or 400 ng/kg/d. Animals were followed for 3 months with serial weights and blood glucose monitoring. These animals were compared with those treated with vehicle alone. Results. Of the group treated with ALR at 40 ng/kg/day for 14 days, 89% (eight of nine) were euglycemic (P=0.0003). Of the group treated with ALR at 400 ng/kg/day for 14 days, 88% (seven of eight) were euglycemic (P=0.0007). Of the group treated with vehicle alone, none of the six were euglycemic. Euglycemia is defined here as glucose<200 mg/dl for 3 days. Pathology of the intramuscular transplant site showed patches of islet tissue embedded in fat. These patches demonstrated insulin immunoreactivity. Conclusions. Diabetes was reversed in a significantly greater proportion of FP + ALR-treated recipients than those animals treated with vehicle alone. Local delivery of growth factors my be used as an adjunct to FP transplantation to improve the rate of success. This in situ model may be useful to further evaluate other soluble factors

    X-rays Studies of the Solar System

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    X-ray observatories contribute fundamental advances in Solar System studies by probing Sun-object interactions, developing planet and satellite surface composition maps, probing global magnetospheric dynamics, and tracking astrochemical reactions. Despite these crucial results, the technological limitations of current X-ray instruments hinder the overall scope and impact for broader scientific application of X-ray observations both now and in the coming decade. Implementation of modern advances in X-ray optics will provide improvements in effective area, spatial resolution, and spectral resolution for future instruments. These improvements will usher in a truly transformative era of Solar System science through the study of X-ray emission.Comment: White paper submitted to Astro2020, the Astronomy and Astrophysics Decadal Surve

    Lymphovascular space invasion and lack of downstaging after neoadjuvant chemotherapy are strong predictors of adverse outcome in young women with locally advanced breast cancer

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    Younger age diagnosis of breast cancer is a predictor of adverse outcome. Here, we evaluate prognostic factors in young women with locally advanced breast cancer (LABC). We present a retrospective review of 104 patients younger than 40 years with LABC treated with surgery, radiotherapy (RT), and chemotherapy from 2003 to 2014. Patient‐, tumor‐, and treatment‐related factors important for overall survival (OS), local/regional recurrence (LRR), distant metastasis (DM), and recurrence‐free survival (RFS) were evaluated. Mean age at diagnosis was 34 years (23–39 years) with a median follow‐up of 47 months (8–138 months). Breast‐conserving surgery was performed in 27%. Axillary lymph node dissection was performed in 85%. Sixty percent of patients received neoadjuvant chemotherapy with 19% achieving pathologic complete response (pCR), and 61% downstaged. Lymph node positivity was present in 91% and lymphovascular space invasion (LVSI) in 35%. Thirty‐two percent of patients had triple negative tumors (TN, ER‐/PR‐/HER2 nonamplified). Four‐year OS and RFS was 84% and 71%, respectively. Factors associated with worse OS on multivariate analysis include TN status, LVSI, and number of positive lymph nodes. LVSI was also associated with DM and LRR, as well as worse RFS. Downstaging was associated with improved 4 year RFS in patients receiving neoadjuvant chemotherapy (74% vs. 38%, P = 0.002). With high risks of recurrence and inferior OS compared to older women, breast cancer in young women can be difficult to treat. Among additional factors, presence of LVSI and lack of downstaging portends a particularly worse prognosis

    Threats to kill: a follow-up study

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    Background. Mental health clinicians are frequently asked to assess the risks presented by patients making threats to kill, but there are almost no data to guide such an evaluation. Method. This data linkage study examined serious violence following making threats to kill and the potential role of mental disorder. A total of 613 individuals convicted of threats to kill had their prior contact with public mental health services established at the time of the index offence. The group&apos;s subsequent criminal convictions were established 10 years later using the police database. Death from suicidal or homicidal violence was also established. Results. Within 10 years, 44 % of threateners were convicted of further violent offending, including 19 (3 %) homicides. Those with histories of psychiatric contact (40 %) had a higher rate (58 %) of subsequent violence. The highest risks were in substance misusers, mentally disordered, young, and those without prior criminal convictions. Homicidal violence was most frequent among threateners with a schizophrenic illness. Sixteen threateners (2.6 %) killed themselves, and three were murdered. Conclusions. In contrast to the claims in the literature that threats are not predictive of subsequent violence, this study revealed high rates of assault and even homicide following threats to kill. The mentally disordered were overrepresented among threat offenders and among those at high risk of subsequent violence. The mentally disordered threateners at highest risk of violence were young, substance abusing, but not necessarily with prior convictions. Those who threaten others were also found to be at greater risk of killing themselves or being killed

    Surgical protocol violations in children with renal tumors provides an opportunity to improve pediatric cancer care: a report from the Children’s Oncology Group

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    BackgroundThe purpose of this study was to evaluate the frequency and characteristics of surgical protocol violations (SPVs) among children undergoing surgery for renal tumors who were enrolled on the Children’s Oncology Group (COG) renal tumor biology and classification study AREN03B2.MethodsAREN03B2 was opened in February 2006, and as on March 31, 2013, there were 3,664 eligible patients. The surgical review forms for 3,536 patients with unilateral disease were centrally reviewed for SPVs. The frequency, type, number of violations, institutional prevalence, and quartiles for SPVs were assessed.ResultsOf the 3,536 patients, there were a total of 505 with at least one SPV (564 total SPVs reported), for an overall incidence of 14.28%. The types of SPVs included a lack of lymph node sampling in 365 (64.7%), avoidable spill in 61 (10.8%), biopsy immediately before nephrectomy in 89 (15.8%), an incorrect abdominal incision in 32 (5.7%), and unnecessary resection of organs in 17 (3.0%). The SPVs occurred in 163 of 215 participating institutions (75.8%). For centers with at least one SPV, the mean number of SPVs reported was 3.10 ± 2.39 (mean ± standard deviation). The incidence of protocol violation per institution ranged from 0 to 67%. Centers with an average of ≤1 case/year had an incidence of SPVs of 12.2 ± 3.8%, those with an average of >1 to 0.05).ConclusionsSPVs that potentially result in additional exposure to chemotherapy and radiation therapy are not uncommon in children undergoing resection of renal malignancies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134088/1/pbc26083.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134088/2/pbc26083_am.pd
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