3,131 research outputs found
An Entomopathogenic Nematode by Any Other Name
Among the diversity of insect-parasitic nematodes, entomopathogenic nematodes (EPNs) are distinct, cooperating with insect-pathogenic bacteria to kill insect hosts. EPNs have adapted specific mechanisms to associate with and transmit bacteria to insect hosts. New discoveries have expanded this guild of nematodes and refine our understanding of the nature and evolution of insectânematode associations. Here, we clarify the meaning of âentomopathogenicâ in nematology and argue that EPNs must rapidly kill their hosts with the aid of bacterial partners and must pass on the associated bacteria to future generations
High Energy Cosmic-ray Diffusion in Molecular Clouds: A Numerical Approach
The propagation of high-energy cosmic rays through giant molecular clouds
constitutes a fundamental process in astronomy and astrophysics. The diffusion
of cosmic-rays through these magnetically turbulent environments is often
studied through the use of energy-dependent diffusion coefficients, although
these are not always well motivated theoretically. Now, however, it is feasible
to perform detailed numerical simulations of the diffusion process
computationally. While the general problem depends upon both the field
structure and particle energy, the analysis may be greatly simplified by
dimensionless analysis. That is, for a specified purely turbulent field, the
analysis depends almost exclusively on a single parameter -- the ratio of the
maximum wavelength of the turbulent field cells to the particle gyration
radius. For turbulent magnetic fluctuations superimposed over an underlying
uniform magnetic field, particle diffusion depends on a second dimensionless
parameter that characterizes the ratio of the turbulent to uniform magnetic
field energy densities. We consider both of these possibilities and parametrize
our results to provide simple quantitative expressions that suitably
characterize the diffusion process within molecular cloud environments. Doing
so, we find that the simple scaling laws often invoked by the high-energy
astrophysics community to model cosmic-ray diffusion through such regions
appear to be fairly robust for the case of a uniform magnetic field with a
strong turbulent component, but are only valid up to TeV particle
energies for a purely turbulent field. These results have important
consequences for the analysis of cosmic-ray processes based on TeV emission
spectra associated with dense molecular clouds.Comment: Accepted for publication in The Astrophysical Journa
Assessing prioritization measures for a private land conservation program in the U.S. Prairie Pothole Region
Private land conservation has become an important tool for protecting biodiversity and habitat, but methods for prioritizing and scheduling conservation on private land are still being developed. While return on investment methods have been suggested as a potential path forward, the different processes linking private landscapes to the socioeconomic systems in which they are embedded create unique challenges for scheduling conservation with this approach. We investigated a range of scheduling approaches within a return on investment framework for breeding waterfowl and broods in the Prairie Pothole Region of North Dakota, South Dakota, and Montana. Current conservation targeting for waterfowl in the region focuses mostly on the distribution and abundance of breeding waterfowl. We tested whether MaxGain approaches for waterfowl conservation differed from MinLoss approaches in terms of return on investment and which approach performed best in avoiding loss of waterfowl and broods separately. We also examined variation in results based upon the temporal scale of the abundance layers used for input and compared the region's current scheduling approach with results from our simulations. Our results suggested that MinLoss was the most efficient scheduling approach for both breeding waterfowl and broods and that using just breeding waterfowl to target areas for conservation programs might cause organizations to overlook important areas for broods, particularly over shorter timespans. The higher efficiency of MinLoss approaches in our simulations also indicated that incorporating probability of wetland drainage into decision-making improved the overall return on investment. We recommend that future conservation scheduling for easements in the region and for private land conservation in general include some form of return on investment or cost-effective analysis to make conservation more transparent
Improving treatment and survival: a populationâbased study of current outcomes after a hepatic resection in patients with metastatic colorectal cancer
AbstractBackgroundPopulationâbased studies historically report underutilization of a resection in patients with colorectal metastases to the liver. Recent data suggest limitations of the methods in the historical analysis. The present study examines trends in a hepatic resection and survival among Medicare recipients with hepatic metastases.MethodsMedicare recipients with incident colorectal cancer diagnosed between 1991 and 2009 were identified in the SEER(Surveillance, Epidemiology and End Results)âMedicare dataset. Patients were stratified into historical (1991â2001) and current (2002â2009) cohorts. Analyses compared treatment, periâoperative outcomes and survival.ResultsOf 31 574 patients with metastatic colorectal cancer to the liver, 14 859 were in the current cohort treated after 2002 and 16 715 comprised the historical control group. The overall proportion treated with a hepatic resection increased significantly during the study period (P< 0.001) with pre/post change from 6.5% preâ2002 to 7.5% currently (P < 0.001). Over time, haemorrhagic and infectious complications declined (both P †0.047), but 30âday mortality was similar (3.5% versus 3.9%, P = 0.660). After adjusting for predictors of survival, the use of a hepatic resection [hazard ratio (HR) = 0.40, 95% confidence interval (CI): 0.38â0.42, P < 0.001] and treatment after 2002 (HR = 0.88, 95% CI: 0.86â0.90, P < 0.001) were associated with a reduced risk of death.ConclusionsCase identification using International Classification of Diseases, 9th Revision (ICDâ9) codes is imperfect; however, comparison of trends over time suggests an improvement in multimodality therapy and survival in patients with colorectal metastases to the liver
Managing hybridization of a recovering endangered species: The red wolf \u3ci\u3eCanis rufus\u3c/i\u3e as a case study
Hybridization presents a unique challenge for conservation biologists and managers. While hybridization is an important evolutionary process, hybridization is also a threat formany native species. The endangered species recovery effort for the red wolf Canis rufus is a classic system for understanding and addressing the challenges of hybridization. From 1987â1993, 63 red wolves were released from captivity in eastern North Carolina, USA, to establish a free-ranging, non-essential experimental population. By 1999, managers recognized hybridization with invasive coyotes Canis latrans was the single greatest threat to successful recovery, and an adaptive management plan was adopted with innovative approaches for managing the threat of hybridization. Here we review the application and results of the adaptive management efforts from 1993 to 2013 by comparing: (1) the numbers of wolves, coyotes, and hybrids captured, (2) the numbers of territorial social groups with presumed breeding capabilities, (3) the number of red wolf and hybrid litters documented each year and (4) the degree of coyote introgression into the wild red wolf gene pool. We documented substantial increases in the number of known red wolves and red wolf social groups from 1987â2004 followed by a plateau and slight decline by 2013.The number of red wolf litters exceeded hybrid litters each year and the proportion of hybrid litters per year averaged 21%. The genetic composition of the wild red wolf population is estimated to include \u3c 4% coyote ancestry from recent introgression since reintroduction. We conclude that the adaptive management plan was effective at reducing the introgression of coyote genes into the red wolf population, but population recovery of red wolves will require continuation of the current management plan, or alternative approaches, for the foreseeable future. More broadly, we discuss the lessons learned from red wolf adaptive management that could assist other endangered species recovery efforts facing the challenge of minimizing hybridizatio
Detection of filovirus-reactive antibodies in Australian bat species
Bats have been implicated as the reservoir hosts of filoviruses in Africa, with serological evidence of filoviruses in various bat species identified in other countries. Here, serum samples from 190 bats, comprising 12 different species, collected in Australia were evaluated for filovirus antibodies. An in-house indirect microsphere assay to detect antibodies that cross-react with Ebola virus (Zaire ebolavirus; EBOV) nucleoprotein (NP) followed by an immunofluorescence assay (IFA) were used to confirm immunoreactivity to EBOV and Reston virus (Reston ebolavirus; RESTV). We found 27 of 102 Yinpterochiroptera and 19 of 88 Yangochiroptera samples were positive to EBOV NP in the microsphere assay. Further testing of these NP positive samples by IFA revealed nine bat sera that showed binding to ebolavirus-infected cells. This is the first report of filovirus-reactive antibodies detected in Australian bat species and suggests that novel filoviruses may be circulating in Australian bats
Complete Genome Sequence of Streptococcus pneumoniae Strain BVJ1JL, a Serotype 1 Carriage Isolate from Malawi.
Streptococcus pneumoniae is a leading cause of pneumonia, meningitis, and bacteremia. Serotype 1 is rarely carried but is commonly associated with invasive pneumococcal disease, and in the African "meningitis belt," it is prone to cause cyclical epidemics. We report the complete genome sequence of S. pneumoniae serotype 1 strain BVJ1JL, isolated in Malawi
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Recent Incarceration, Substance Use, Overdose, and Service Use Among People Who Use Drugs in Rural Communities
Importance: Drug use and incarceration have a substantial impact on rural communities, but factors associated with the incarceration of rural people who use drugs (PWUD) have not been thoroughly investigated. Objective: To characterize associations between recent incarceration, overdose, and substance use disorder (SUD) treatment access among rural PWUD. Design, setting, and participants: For this cross-sectional study, the Rural Opioid Initiative research consortium conducted a survey in geographically diverse rural counties with high rates of overdose across 10 US states (Illinois, Wisconsin, North Carolina, Oregon, Kentucky, West Virginia, Ohio, Massachusetts, New Hampshire, and Vermont) between January 25, 2018, and March 17, 2020, asking PWUD about their substance use, substance use treatment, and interactions with the criminal legal system. Participants were recruited through respondent-driven sampling in 8 rural US regions. Respondents who were willing to recruit additional respondents from their personal networks were enrolled at syringe service programs, community support organizations, and through direct community outreach; these so-called seed respondents then recruited others. Of 3044 respondents, 2935 included participants who resided in rural communities and reported past-30-day injection of any drug or use of opioids nonmedically via any route. Data were analyzed from February 8, 2022, to September 15, 2023. Exposure: Recent incarceration was the exposure of interest, defined as a report of incarceration in jail or prison for at least 1 day in the past 6 months. Main outcomes and measures: The associations between PWUD who were recently incarcerated and main outcomes of treatment use and overdose were examined using logistic regression. Results: Of 2935 participants, 1662 (56.6%) were male, 2496 (85.0%) were White; the mean (SD) age was 36 (10) years; and in the past 30 days, 2507 (85.4%) reported opioid use and 1663 (56.7%) reported injecting drugs daily. A total of 1224 participants (41.7%) reported recent incarceration, with a median (IQR) incarceration of 15 (3-60) days in the past 6 months. Recent incarceration was associated with past-6-month overdose (adjusted odds ratio [AOR], 1.38; 95% CI, 1.12-1.70) and recent SUD treatment (AOR, 1.62; 95% CI, 1.36-1.93) but not recent medication for opioid use disorder (MOUD; AOR, 1.03; 95% CI, 0.82-1.28) or currently carrying naloxone (AOR, 1.02; 95% CI, 0.86-1.21). Conclusions and relevance: In this cross-sectional study of PWUD in rural areas, participants commonly experienced recent incarceration, which was not associated with MOUD, an effective and lifesaving treatment. The criminal legal system should implement effective SUD treatment in rural areas, including MOUD and provision of naloxone, to fully align with evidence-based SUD health care policies.</p
External beam irradiation of myocardial carcinoid metastases: a case report
The heart is an exceedingly rare site of metastatic involvement in carcinoid tumors. Only nineteen cases have been described in the literature over the past 30 years. We report here on a patient who presented with progressive carcinoid syndrome despite surgical resection of her liver metastases. She was found to have cardiac metastases on inidium-111-pentetreotide scintigraphy and subsequently underwent external beam radiation to the heart resulting in symptomatic palliation of her syndrome and objective radiographic response. To our knowledge, this is the first reported case of metastatic cardiac carcinoid treated with external beam irradiation
SMRT-AgRenSeq-d in potato (Solanum tuberosum) as a method to identify candidates for the nematode resistance Gpa5
Potato is the third most important food crop in the world. Diverse pathogens threaten sustainable crop production but can be controlled, in many cases, through the deployment of disease resistance genes belonging to the family of nucleotide-binding, leucine-rich-repeat (NLR) genes. To identify effective disease resistance genes in established varieties, we have successfully established SMRT-AgRenSeq in tetraploid potatoes and have further enhanced the methodology by including dRenSeq in an approach that we term SMR-AgRenSeq-d. The inclusion of dRenSeq enables the filtering of candidates after the association analysis by establishing a presence/absence matrix across resistant and susceptible varieties that is translated into an F1 score. Using a SMRT-RenSeq-based sequence representation of the NLRome from the cultivar Innovator, SMRT-AgRenSeq-d analyses reliably identified the late blight resistance benchmark genes Rpi-R1, Rpi-R2-like, Rpi-R3a, and Rpi-R3b in a panel of 117 varieties with variable phenotype penetrations. All benchmark genes were identified with an F1 score of 1, which indicates absolute linkage in the panel. This method also identified nine strong candidates for Gpa5 that controls the potato cyst nematode (PCN) species Globodera pallida (pathotypes Pa2/3). Assuming that NLRs are involved in controlling many types of resistances, SMRT-AgRenSeq-d can readily be applied to diverse crops and pathogen systems.</p
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