3,066 research outputs found
Answering Complex Questions as We Make Headway on Annual Grasses and Fire
Annual grasses challenge our ability to meet forage production and plant community conservation objectives. Direct competition, potential mutualism, and shortened fire return interval interplay resulting in complexity of how to meet challenges we face. Bromus tectorum presents challenges to sagebrush dominated plant communities with shortened fire return intervals and the advancing invasion of Ventenata dubia poses threats to forage production through competitive interactions that may involve mutualism to enhance V. dubia’s invasion of annual and perennial grass dominated plant communities. Use of fuel breaks can reduce the extent of fires and their proper function hinges on their reduced plant biomass in contrast to surrounding vegetation to improve fire fighting ability. Reducing annual grass biomass within fuel breaks reduces fuel continuity and shortens the duration of dry vegetation. Indaziflam and imazapic are two herbicide active ingredients that allow control of annual grasses within fuel breaks and sagebrush plant communities. Aerial application of these herbicides allows us to match control actions to the scope of the problem. These herbicides can also reduce competition from annual grasses, allowing increased cover and diversity of native plant communities. Removal or reduction of annual grasses has improved plant species diversity and forage production
A Tracer Investigation of Pheromone Dispersion in Lodgepole and Ponderosa Pine Forest Canopies
Tracer experiments were conducted in 2000 and 2001 to study spread of insect pheromone plumes in forest canopies. The field sites consisted of lodgepole pine (Pinus contorta) and ponderosa pine (P. ponderosa) canopies in 2000 and 2001, respectively. Ranges of temperature, wind speed, and turbulence conditions were similar in the two campaigns, and field data showed comparable variability on near-instantaneous time scales of wind speed, wind direction, and plume behavior. We developed simple empirical equations to estimate average horizontal and vertical plume spread as functions of standard turbulence statistics, downwind distance from the source, and wind speed. For horizontal plume spread, predicted dispersion coefficients were within a factor of 3, or better, for 97 percent of the observed values in the combined dataset from 2000 and 2001. Likewise, 99 percent of the predicted vertical dispersion coefficients were within a factor of 3 of the observed data
New, efficient, and accurate high order derivative and dissipation operators satisfying summation by parts, and applications in three-dimensional multi-block evolutions
We construct new, efficient, and accurate high-order finite differencing
operators which satisfy summation by parts. Since these operators are not
uniquely defined, we consider several optimization criteria: minimizing the
bandwidth, the truncation error on the boundary points, the spectral radius, or
a combination of these. We examine in detail a set of operators that are up to
tenth order accurate in the interior, and we surprisingly find that a
combination of these optimizations can improve the operators' spectral radius
and accuracy by orders of magnitude in certain cases. We also construct
high-order dissipation operators that are compatible with these new finite
difference operators and which are semi-definite with respect to the
appropriate summation by parts scalar product. We test the stability and
accuracy of these new difference and dissipation operators by evolving a
three-dimensional scalar wave equation on a spherical domain consisting of
seven blocks, each discretized with a structured grid, and connected through
penalty boundary conditions.Comment: 16 pages, 9 figures. The files with the coefficients for the
derivative and dissipation operators can be accessed by downloading the
source code for the document. The files are located in the "coeffs"
subdirector
Relationship of pain and fatigue with health-related quality of life and work in patients with psoriatic arthritis on TNFi: results of a multi-national real-world study
Background/Objective: The incidence of pain and/or fatigue in people with psoriatic arthritis (PsA) is associated with reduced health-related quality of life (HRQoL) and the ability to work, despite modern advanced therapeutic approaches. This real-world, international study examined these relationships in patients with PsA treated with tumour necrosis factor inhibitors (TNFi).
Methods: Data from 13 countries were analysed. Patients with PsA and their physicians completed questionnaires capturing demographics, current therapy, current disease status, HRQoL and work status via Medical Outcomes Study 36-Item Short-Form version 2 (SF-36v2), 3-level 5-dimension EuroQoL questionnaire, Health Assessment Questionnaire Disability Index, and Work Productivity and Activity Impairment (WPAI) questionnaire.
Results: 640 patients with PsA were included who had been receiving TNFi for ≥3 months and had completed SF-36v2 bodily pain and vitality domains. Of these, 33.1%, 29.2% and 37.7% of patients reported no, moderate and severe pain, respectively, and 31.9%, 22.5% and 45.6% of patients reported low, moderate and severe fatigue, respectively. Scores across HRQoL variables and WPAI were significantly different across pain and fatigue cohorts (all p<0.0001), with HRQoL and WPAI measures considerably worse in patients with moderate to severe pain or fatigue than those with low pain or fatigue.
Conclusions: Despite treatment with biologic agents such as TNFi, data from this global study demonstrated that substantial pain and/or fatigue persist in patients with PsA and that these are significantly associated with reduced HRQoL, physical function and work productivity. These findings suggest that there is an unmet need for additional PsA therapies
Unmet needs in psoriatic arthritis patients receiving immunomodulatory therapy: results from a large multinational real-world study
Objective: There are limited data on therapy selection and switching in psoriatic arthritis (PsA). This 18 country, real-world study assessed use and switching of immunomodulatory therapy (biologic/apremilast), the extent of treatment failure and its association with reduced physical functioning, health-related quality of life (HRQoL), and work productivity and activity impairment (WPAI).
Methods: PsA patients under routine care and their treating physicians provided demographics, current therapy, reasons for switching, duration of first therapy, HRQoL, HAQ-DI, and WPAI. Current immunomodulatory therapy was determined as “failing” if, after ≥ 3 months, physician-rated disease severity had worsened, remained severe, was “unstable/deteriorating,” or they were dissatisfied with disease control and/or did not consider treatment a “success.”
Results: Included were 3714 PsA patients; 1455 (40.6%) had never received immunomodulatory therapy; 1796 (50.1%) had ever received 1 immunomodulatory therapy and 331 (9.2%) ≥ 1. Lack of efficacy with first immunomodulatory therapy was the most common reason for switching; patients whose physicians indicated “primary lack of efficacy” as the reason, switched after a mean of 9.4 months. Patients currently failing immunomodulator therapies (n = 246) had poorer HRQoL compared with treatment success (n = 1472) measured by EQ-5D-3L (0.60 vs 0.77%; P < 0.0001); SF-36 PCS (40.8% vs 46.1%; P < 0.0001) MCS (41.1% vs 45.3%; P < 0.0001). Physical functioning, activity, and work productivity were also more impaired (HAQ-DI: 0.88 vs 0.56; activity impairment: 46.7% vs 29.7%; overall work impairment: 35.4% vs 26.1%; all P < 0.0001).
Conclusions: Poor treatment response in PsA is associated with substantial negative patient impact. In cases of primary treatment failure, timely switching is needed
Unmet needs in ankylosing spondylitis patients receiving tumour necrosis factor inhibitor therapy; results from a large multinational real-world study
Background
Symptoms and comorbidities of ankylosing spondylitis (AS) considerably reduce health-related quality of life (HRQoL) and ability to work. This real-world study assessed rates of tumour necrosis factor inhibitor (TNFi) use and switching, treatment failure, and associations between failing TNFi and HRQoL, work productivity and activity impairment (WPAI).
Methods
AS patients and their treating physicians completed questionnaires capturing patient demographics, clinical status, TNFi treatment history, reasons for switching TNFi, HRQoL and WPAI. Current TNFi was determined as “failing” if, after ≥3 months, physician-rated disease severity had worsened, remained severe, was “unstable/deteriorating”, physicians were dissatisfied with disease control and/or did not consider treatment a “success”.
Results
The analysis included 2866 AS patients from 18 countries. Of 2795 patients with complete treatment data, 916 (32.8%) patients had never received TNFi therapy, 1623 (58.1%) patients were receiving their 1st TNFi and 200 (7.2%) patients had ever received ≥2 TNFi (treatment switch). Primary or secondary lack of efficacy were the commonest reasons for switching, and the mean delay in switching after primary lack of efficacy was 11.1 months. 232 (15.4%) patients on TNFi were currently “failing” who, compared to those with treatment success, reported poorer HRQoL: 5-dimension EuroQoL (EQ-5D-3 L): 0.63 vs. 0.78; Medical Outcomes Study Short-Form Health Survey version 2 (SF-36v2) mental component summary (MCS): 41.8 vs. 46.3; physical component summary (PCS): 40.2 vs. 45.1; impaired work productivity: 46.4% vs. 25.0%; and activity: 44.5% vs. 29.6%; all P < 0.001.
Conclusions
Among AS patients, switching TNFi is uncommon and delayed by nearly 1 year despite primary lack of efficacy. Patients currently failing TNFi experience worse physical function, HRQoL and work productivity
The Initial Mass Function of Low-Mass Stars and Brown Dwarfs in Young Clusters
We have obtained images of the Trapezium Cluster (140" x 140"; 0.3 pc x 0.3
pc) with the Hubble Space Telescope Near-Infrared Camera and Multi-Object
Spectrometer (NICMOS). Combining these data with new ground-based K-band
spectra (R=800) and existing spectral types and photometry and the models of
D'Antona & Mazzitelli, we find that the distributions of ages of comparable
samples of stars in the Trapezium, rho Oph, and IC 348 indicate median ages of
\~0.4 Myr for the first two regions and ~1-2 Myr for the latter. The low-mass
IMFs in these sites of clustered star formation are similar over a wide range
of stellar densities and other environmental conditions. With current data, we
cannot rule out modest variations in the substellar mass functions among these
clusters. We then make the best estimate of the true form of the IMF in the
Trapezium by using the evolutionary models of Baraffe et al. and an empirically
adjusted temperature scale and compare this mass function to recent results for
the Pleiades and the field. All of these data are consistent with an IMF that
is flat or rises slowly from the substellar regime to about 0.6 Msun, and then
rolls over into a power law that continues from about 1 Msun to higher masses
with a slope similar to or somewhat larger than the Salpeter value of 1.35. For
the Trapezium, this behavior holds from our completeness limit of ~0.02 Msun
and probably, after a modest completeness correction, even from 0.01-0.02 Msun.
These data include ~50 likely brown dwarfs. We test the predictions of theories
of the IMF against various properties of the observed IMF.Comment: 34 pages, 13 figures, for color image see
http://cfa-www.harvard.edu/~kluhman/trap/colorimage.jp
Surveying the views of pupils attending supplementary schools in England
This report is the first part of a wider research project intended to evaluate the role of supplementary school in supporting pupils’ educational progress. This study reports on the first phase of this research An attitude survey to find out what young people think about mainstream and supplementary education, about the core subjects of reading and mathematics, about themselves as learners and about their reasons for attending supplementary school.. Pupil questionnaires were sent to all schools who were successful in being awarded grants from the support service. Schools were asked to administer the questionnaires to ten nominated pupils within the school, although they could give the questionnaire to more than 10 pupils if they chose. Questionnaires were returned from a total of 772 pupils attending 63 supplementary schools in four major cities in England. This is the first study to systematically explore the attitudes of pupils attending supplementary school in England and is the largest ever study of supplementary schools and their pupils
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