2,648 research outputs found

    Degradation and forgone removals increase the carbon impact of intact forest loss by 626%

    Get PDF
    Intact tropical forests, free from substantial anthropogenic influence, store and sequester large amounts of atmospheric carbon but are currently neglected in international climate policy. We show that between 2000 and 2013, direct clearance of intact tropical forest areas accounted for 3.2% of gross carbon emissions from all deforestation across the pantropics. However, full carbon accounting requires the consideration of forgone carbon sequestration, selective logging, edge effects, and defaunation. When these factors were considered, the net carbon impact resulting from intact tropical forest loss between 2000 and 2013 increased by a factor of 6 (626%), from 0.34 (0.37 to 0.21) to 2.12 (2.85 to 1.00) petagrams of carbon (equivalent to approximately 2 years of global land use change emissions). The climate mitigation value of conserving the 549 million ha of tropical forest that remains intact is therefore significant but will soon dwindle if their rate of loss continues to accelerate

    Histotripsy Erosion of Model Urinary Calculi

    Full text link
    Background and Purpose: Histotripsy is a pulsed focused ultrasound technology in which initiation and control of acoustic cavitation allow for precise mechanical fractionation of tissues. The present study examines the feasibility of using histotripsy for erosion of urinary calculi. Materials and Methods: Histotripsy treatment was delivered from a 750-kHz transducer in the form of 5-cycle acoustic pulses at a 1-kHz pulse repetition frequency. Model stones were sonicated for 5 minutes at peak negative pressures (p-) of 10, 15, 19, 22, and 24-MPa. Resulting fragment sizes and comminution rates were assessed and compared with those achieved with a piezoelectric lithotripter (Wolf Piezolith 3000) operated at 2-Hz pulse repetition frequency and power level 17 (p- = 14-MPa). Results: Histotripsy eroded the surface of stones producing fine (<100--m) particulate debris in contrast to the progressive and incomplete subdivision of stones achieved with piezoelectric lithotripsy. The histotripsy erosion rate increased with increasing peak negative pressure from 10 to 19-MPa and then saturated, yielding an average rate of 87.9+/-12.8 mg/min at maximum treatment intensity. Piezoelectric lithotripsy achieved an average treatment rate of 110.7+/-27.4 mg/min. Conclusions: Histotripsy comminution of urinary calculi is a surface erosion phenomenon that is mechanistically distinct from conventional shockwave lithotripsy (SWL), producing only fine debris as opposed to coarse fragments. These characteristics suggest that histotripsy offers a potential adjunct to traditional SWL procedures, and synergistic interplay of the two modalities may lead to possible increases in both rate and degree of stone fragmentation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90440/1/end-2E2010-2E0407.pd

    Evidence for a dominant-negative effect in ACTA1 nemaline myopathy caused by abnormal folding, aggregation and altered polymerization of mutant actin isoforms

    Get PDF
    We have studied a cohort of nemaline myopathy (NM) patients with mutations in the muscle α-skeletal actin gene (ACTA1). Immunoblot analysis of patient muscle demonstrates increased γ-filamin, myotilin, desmin and α-actinin in many NM patients, consistent with accumulation of Z line-derived nemaline bodies. We demonstrate that nebulin can appear abnormal secondary to a primary defect in actin, and show by isoelectric focusing that mutant actin isoforms are present within insoluble actin filaments isolated from muscle from two ACTA1 NM patients. Transfection of C2C12 myoblasts with mutant actinEGFP constructs resulted in abnormal cytoplasmic and intranuclear actin aggregates. Intranuclear aggregates were observed with V163L-, V163M- and R183G-actinEGFP constructs, and modeling shows these residues to be adjacent to the nuclear export signal of actin. V163L and V163M actin mutants are known to cause intranuclear rod myopathy, however, intranuclear bodies were not reported in patient R183G. Transfection studies in C2C12 myoblasts showed significant alterations in the ability of V136L and R183G actin mutants to polymerize and contribute to insoluble actin filaments. Thus, we provide direct evidence for a dominant-negative effect of mutant actin in NM. In vitro studies suggest that abnormal folding, altered polymerization and aggregation of mutant actin isoforms are common properties of NM ACTA1 mutants. Some of these effects are mutation-specific, and likely result in variations in the severity of muscle weakness seen in individual patients. A combination of these effects contributes to the common pathological hallmarks of NM, namely intranuclear and cytoplasmic rod formation, accumulation of thin filaments and myofibrillar disorganizatio

    A Randomized Trial of Vaginal Antiseptic Preparation Solutions to Reduce Bacteria Colony Counts in Patients Undergoing Vaginal Surgery

    Get PDF
    Antiseptic preparation of surgical sites is known to reduce the rate of infective complications. However, surgical site infections (SSI) remain a leading cause of post-operative hospitalizations, increasing patient stress and cost for the healthcare system.1-7 In gynecologic surgery, preparation of the vagina is performed to reduce bacterial load prior to surgery, though it is known to remain contaminated.3 In the US, only solutions containing povidone-iodine (PI) are FDA approved for vaginal preparation; though, a 2018 ACOG Practice Bulletin lists chlorhexidine gluconate (CHG) with low (\u3c4%) alcohol concentrations as a reasonable option for off-label use.3 Other preparations for vaginal surgery have been reported including baby shampoo (BS) and a commercially available preparation, containing PCMX (para-chloro-meta-xylenol, Techni-care®, chloroxylenol), that is marketed specifically for use with mucous membranes.8-12 There is a growing need to establish evidence-based alternatives to iodine for vaginal preparation for patients with allergies or sensitivity to iodine-containing products while minimizing postoperative irritation. One retrospective study comparing BS to PI in gynecologic surgeries showed a non-significant lower rate of surgical site infection with BS.9 One major challenge for determining effectiveness of surgical scrubs for reducing SSI is the relatively rare occurrence of postoperative infection. As an alternative proxy for infection colony counts of bacteria/fungi, before and after preparation, have been used.12,13 BS has been shown to reduce bacterial loads in non-gynecologic surgery, but there is limited data regarding its use in vaginal surgery, even though surgeons have been using BS in cases of iodine allergy or intolerance to other antiseptics.9-12CHG use in vaginal surgery has been debated due to concerns about vaginal irritation, however studies have demonstrated that alteration of the solution to 2-4% chlorhexidine with low (4%) alcohol concentration was associated with mild to no vaginal irritation. CHG showed similar reduction in post-incision bacterial counts and wound infections in cesarean delivery, and reduced colony counts during hysterectomy (when compared to PI).14-20 PCMX and CHG were shown to significantly reduce bacterial colonization of extracted root canals, and PCMX has been marketed specifically for vaginal antiseptic preparation.21 While some information on the effectiveness of these four antiseptic preparations has been documented in the literature, at this time there are no randomized controlled trials comparing these solutions in the context of vaginal surgery. Further evaluation and research of antiseptic solutions is warranted to provide evidence for best practices in minimizing infection and irritation. The purpose of this study was to compare the effectiveness of three antiseptic solutions with the standard, PI, for reducing bacterial colonies as a proxy for SSI, and to assess postoperative irritation and infection symptoms

    Close companions around young stars

    Get PDF
    Multiplicity is a fundamental property that is set early during stellar lifetimes, and it is a stringent probe of the physics of star formation. The distribution of close companions around young stars is still poorly constrained by observations. We present an analysis of stellar multiplicity derived from APOGEE-2 spectra obtained in targeted observations of nearby star-forming regions. This is the largest homogeneously observed sample of high-resolution spectra of young stars. We developed an autonomous method to identify double lined spectroscopic binaries (SB2s). Out of 5007 sources spanning the mass range of \sim0.05--1.5 \msun, we find 399 binaries, including both RV variables and SB2s. The mass ratio distribution of SB2s is consistent with a uniform for q0.95q0.95. The period distribution is consistent with what has been observed in close binaries (<10<10 AU) in the evolved populations. Three systems are found to have qq\sim0.1, with a companion located within the brown dwarf desert. There are not any strong trends in the multiplicity fraction (MF) as a function of cluster age from 1 to 100 Myr. There is a weak dependence on stellar density, with companions being most numerous at Σ30\Sigma_*\sim30 stars/pc2^{-2}, and decreasing in more diffuse regions. Finally, disk-bearing sources are deficient in SB2s (but not RV variables) by a factor of \sim2; this deficit is recovered by the systems without disks. This may indicate a quick dispersal of disk material in short-period equal mass systems that is less effective in binaries with lower qq.Comment: 25 pages, 20 figures. Accepted to A

    Acquisition and Evolution of Plant Pathogenesis–Associated Gene Clusters and Candidate Determinants of Tissue-Specificity in Xanthomonas

    Get PDF
    Xanthomonas is a large genus of plant-associated and plant-pathogenic bacteria. Collectively, members cause diseases on over 392 plant species. Individually, they exhibit marked host- and tissue-specificity. The determinants of this specificity are unknown.To assess potential contributions to host- and tissue-specificity, pathogenesis-associated gene clusters were compared across genomes of eight Xanthomonas strains representing vascular or non-vascular pathogens of rice, brassicas, pepper and tomato, and citrus. The gum cluster for extracellular polysaccharide is conserved except for gumN and sequences downstream. The xcs and xps clusters for type II secretion are conserved, except in the rice pathogens, in which xcs is missing. In the otherwise conserved hrp cluster, sequences flanking the core genes for type III secretion vary with respect to insertion sequence element and putative effector gene content. Variation at the rpf (regulation of pathogenicity factors) cluster is more pronounced, though genes with established functional relevance are conserved. A cluster for synthesis of lipopolysaccharide varies highly, suggesting multiple horizontal gene transfers and reassortments, but this variation does not correlate with host- or tissue-specificity. Phylogenetic trees based on amino acid alignments of gum, xps, xcs, hrp, and rpf cluster products generally reflect strain phylogeny. However, amino acid residues at four positions correlate with tissue specificity, revealing hpaA and xpsD as candidate determinants. Examination of genome sequences of xanthomonads Xylella fastidiosa and Stenotrophomonas maltophilia revealed that the hrp, gum, and xcs clusters are recent acquisitions in the Xanthomonas lineage.Our results provide insight into the ancestral Xanthomonas genome and indicate that differentiation with respect to host- and tissue-specificity involved not major modifications or wholesale exchange of clusters, but subtle changes in a small number of genes or in non-coding sequences, and/or differences outside the clusters, potentially among regulatory targets or secretory substrates

    GPI spectra of HR 8799 c, d, and e from 1.5 to 2.4μ\mum with KLIP Forward Modeling

    Full text link
    We explore KLIP forward modeling spectral extraction on Gemini Planet Imager coronagraphic data of HR 8799, using PyKLIP and show algorithm stability with varying KLIP parameters. We report new and re-reduced spectrophotometry of HR 8799 c, d, and e in H & K bands. We discuss a strategy for choosing optimal KLIP PSF subtraction parameters by injecting simulated sources and recovering them over a range of parameters. The K1/K2 spectra for HR 8799 c and d are similar to previously published results from the same dataset. We also present a K band spectrum of HR 8799 e for the first time and show that our H-band spectra agree well with previously published spectra from the VLT/SPHERE instrument. We show that HR 8799 c and d show significant differences in their H & K spectra, but do not find any conclusive differences between d and e or c and e, likely due to large error bars in the recovered spectrum of e. Compared to M, L, and T-type field brown dwarfs, all three planets are most consistent with mid and late L spectral types. All objects are consistent with low gravity but a lack of standard spectra for low gravity limit the ability to fit the best spectral type. We discuss how dedicated modeling efforts can better fit HR 8799 planets' near-IR flux and discuss how differences between the properties of these planets can be further explored.Comment: Accepted to AJ, 25 pages, 16 Figure
    corecore