1,025 research outputs found
Landowners' perceptions on the use of prescribed fire as a management tool
The purpose of this project is to determine landownersâ perceptions on the use of
prescribed fire as a management tool. The majority of Texas rangelands are privately
owned, and the sustainable management of almost all of the stateâÂÂs rangelands is
contingent upon private land management decisions. Therefore, it is imperative for
policy makers and extension agencies to understand landownersâ perceptions, interests
and concerns about alternative land management techniques. This is especially
important for the use of prescribed fire, which has been identified as a critical
management tool for maintaining the productivity of most Texas rangelands yet many
landowners do not include it as an integral practice in managing their land. A better
understanding of landownersâ perspective of the use of fire could facilitate the increased
use of this management tool through the development of effective educational, costshare
and fire planning programs.
The study reported here consisted of a mail survey of all 185 members of the
Edwards Plateau Prescribed Burn Association (EPPBA) and 600 landowners in six
counties in Texas. Four of those counties were located in the Edwards Plateau (Sutton, Schleicher, Mason, Llano) and two counties were located in the Rolling Plains
(Throckmorton, Shackleford). In each county, 100 landowners possessing at least 50
acres of land were randomly selected for inclusion in the survey. The mail survey
approach followed DilmanâÂÂs five-step mailing procedure.
Fire is an important rangeland management tool, but in a state where the majority
of the land is privately owned fire suppression is still a dominant perspective. Our study
suggests that important efforts to increase the use of prescribed fire include, educational
programs about use of fire by landowners, increased assistance with prescribed fire
plans, cost-sharing programs for fire implementation, and reduction in the legal liability
associated with fire that burns out of control. Encouraging agencies to back educational
programs and help teach landowners about the effects and uses of fire (burn plan
assistance), and developing a resource pool to underwrite fire policies could increase the
interest in and risk associated with the use of prescribed fires to more effectively manage
rangelands in Texas, and elsewhere
DEVELOPING A ROBOTICS OUTREACH PROGRAM
The WPI-EBOT educational robotics program was designed as a low-cost way to teach basic engineering and programming principles and to encourage high school students to pursue an education in engineering or science. The project group recruited local high schools, trained teachers at those schools, and worked directly with students to assist them in building a competitive robot. The schools\u27 response to the project was overwhelmingly positive, and they plan to remain involved for years to come
Cosmology is not a Renormalization Group Flow
A critical examination is made of two simple implementations of the idea that
cosmology can be viewed as a renormalization group flow. Both implementations
are shown to fail when applied to a massless, minimally coupled scalar with a
quartic self-interaction on a locally de Sitter background. Cosmological
evolution in this model is not driven by any RG screening of couplings but
rather by inflationary particle production gradually filling an initially empty
universe with a sea of long wavelength scalars.Comment: 4 pages, no figures, uses revtex4, version 2 revised slightly for
publication in Physical Review Letter
A guide for managing patients with stage I NSCLC: Deciding between lobectomy, segmentectomy, wedge, SBRT and ablation-part 2: Systematic review of evidence regarding resection extent in generally healthy patients
Background: Clinical decision-making for patients with stage I lung cancer is complex. It involves multiple options (lobectomy, segmentectomy, wedge, stereotactic body radiotherapy, thermal ablation), weighing multiple outcomes (e.g., short-, intermediate-, long-term) and multiple aspects of each (e.g., magnitude of a difference, the degree of confidence in the evidence, and the applicability to the patient and setting at hand). A structure is needed to summarize the relevant evidence for an individual patient and to identify which outcomes have the greatest impact on the decision-making.
Methods: A PubMed systematic review from 2000-2021 of outcomes after lobectomy, segmentectomy and wedge resection in generally healthy patients is the focus of this paper. Evidence was abstracted from randomized trials and non-randomized comparisons with at least some adjustment for confounders. The analysis involved careful assessment, including characteristics of patients, settings, residual confounding etc. to expose degrees of uncertainty and applicability to individual patients. Evidence is summarized that provides an at-a-glance overall impression as well as the ability to delve into layers of details of the patients, settings and treatments involved.
Results: In healthy patients there is no short-term benefit to sublobar resection
Conclusions: A systematic, comprehensive summary of evidence regarding resection extent in healthy patients with attention to aspects of applicability, uncertainty and effect modifiers provides a foundation on which to build a framework for individualized clinical decision-making
A guide for managing patients with stage I NSCLC: Deciding between lobectomy, segmentectomy, wedge, SBRT and ablation-part 3: Systematic review of evidence regarding surgery in compromised patients or specific tumors
Background: Clinical decision-making for patients with stage I lung cancer is complex. It involves multiple options [lobectomy, segmentectomy, wedge, stereotactic body radiotherapy (SBRT), thermal ablation], weighing multiple outcomes (e.g., short-, intermediate-, long-term) and multiple aspects of each (e.g., magnitude of a difference, the degree of confidence in the evidence, and the applicability to the patient and setting at hand). A structure is needed to summarize the relevant evidence for an individual patient and to identify which outcomes have the greatest impact on the decision-making.
Methods: A PubMed systematic review from 2000-2021 of outcomes after lobectomy, segmentectomy and wedge resection in older patients, patients with limited pulmonary reserve and favorable tumors is the focus of this paper. Evidence was abstracted from randomized trials and non-randomized comparisons (NRCs) with adjustment for confounders. The analysis involved careful assessment, including characteristics of patients, settings, residual confounding etc. to expose degrees of uncertainty and applicability to individual patients. Evidence is summarized that provides an at-a-glance overall impression as well as the ability to delve into layers of details of the patients, settings and treatments involved.
Results: In older patients, perioperative mortality is minimally altered by resection extent and only slightly affected by increasing age; sublobar resection may slightly decrease morbidity. Long-term outcomes are worse after lesser resection; the difference is slightly attenuated with increasing age. Reported short-term outcomes are quite acceptable in (selected) patients with severely limited pulmonary reserve, not clearly altered by resection extent but substantially improved by a minimally invasive approach. Quality-of-life (QOL) and impact on pulmonary function hasn\u27t been well studied, but there appears to be little difference by resection extent in older or compromised patients. Patient selection is paramount but not well defined. Ground-glass and screen-detected tumors exhibit favorable long-term outcomes regardless of resection extent; however solid tumors \u3c1 cm are not a reliably favorable group.
Conclusions: A systematic, comprehensive summary of evidence regarding resection extent in compromised patients and favorable tumors with attention to aspects of applicability, uncertainty and effect modifiers provides a foundation for a framework for individualized decision-making
A guide for managing patients with stage I NSCLC: Deciding between lobectomy, segmentectomy, wedge, SBRT and ablation-part 4: Systematic review of evidence involving SBRT and ablation
Background: Clinical decision-making for patients with stage I lung cancer is complex. It involves multiple options [lobectomy, segmentectomy, wedge, stereotactic body radiotherapy (SBRT), thermal ablation], weighing multiple outcomes (e.g., short-, intermediate-, long-term) and multiple aspects of each (e.g., magnitude of a difference, the degree of confidence in the evidence, and the applicability to the patient and setting at hand). A structure is needed to summarize the relevant evidence for an individual patient and to identify which outcomes have the greatest impact on the decision-making.
Methods: A PubMed systematic review from 2000-2021 of outcomes after SBRT or thermal ablation
Results: Short-term outcomes are meaningfully better after SBRT than resection. SBRT doesn\u27t affect quality-of-life (QOL), on average pulmonary function is not altered, but a minority of patients may experience gradual late toxicity. Adjusted non-randomized comparisons demonstrate a clinically relevant detriment in long-term outcomes after SBRT
Conclusions: A systematic, comprehensive summary of evidence regarding Stereotactic Body Radiotherapy or thermal ablatio
Cosmological Tests of Gravity
Modifications of general relativity provide an alternative explanation to
dark energy for the observed acceleration of the universe. We review recent
developments in modified gravity theories, focusing on higher dimensional
approaches and chameleon/f(R) theories. We classify these models in terms of
the screening mechanisms that enable such theories to approach general
relativity on small scales (and thus satisfy solar system constraints). We
describe general features of the modified Friedman equation in such theories.
The second half of this review describes experimental tests of gravity in
light of the new theoretical approaches. We summarize the high precision tests
of gravity on laboratory and solar system scales. We describe in some detail
tests on astrophysical scales ranging from ~kpc (galaxy scales) to ~Gpc
(large-scale structure). These tests rely on the growth and inter-relationship
of perturbations in the metric potentials, density and velocity fields which
can be measured using gravitational lensing, galaxy cluster abundances, galaxy
clustering and the Integrated Sachs-Wolfe effect. A robust way to interpret
observations is by constraining effective parameters, such as the ratio of the
two metric potentials. Currently tests of gravity on astrophysical scales are
in the early stages --- we summarize these tests and discuss the interesting
prospects for new tests in the coming decade.Comment: Invited review for Annals of Physics; 58 pages, 8 figures
Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV
Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio
Search for stop and higgsino production using diphoton Higgs boson decays
Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top-quark (stop) and the Higgs boson (higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7 inverse femtobarns of proton-proton collision data at sqrt(s) = 8 TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the stop mass below 360 to 410 GeV, depending on the higgsino mass
Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon
The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe
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