Treatment Levels (treatment + level)

Distribution by Scientific Domains

Selected Abstracts

Could rising aquatic carbon dioxide concentrations favour the invasion of elodeids in isoetid-dominated softwater lakes?

Summary 1. During the past century, isoetid vegetation types in softwater lakes have often been invaded by faster-growing elodeids. In these C-limited systems, this may be related to rising aquatic CO2 levels. 2. In a laboratory experiment we tested the growth response of two elodeid species, Myriophyllum alterniflorum and Callitriche hamulata, at four different CO2 levels, ranging from 20 to 230 ,mol L,1. In addition, we tested the effect of the nutrient status of the sediment on the growth of C. hamulata at the different CO2 levels. 3. Shoot and root growth increased with rising CO2 availability. Irrespective of sediment type, growth was minimal to negative at the lowest CO2 treatment level, while becoming positive at CO2 levels around 40,50 ,mol L,1. Substantial growth was only obtained when the macrophytes were growing on mesotrophic sediments. The plants reached close to maximal growth at CO2 levels of c. 100 ,mol L,1. 4. Within this experiment, the growth of C. hamulata at CO2 levels above 90 ,mol L,1 may have been limited by N and P availability in both sediment types. The growth rate of M. alterniflorum did not seem to be limited by N and P availability, most likely due to its much higher relative root production. 5. The experimental results show that neither M. alterniflorum nor C. hamulata is able to invade isoetid-dominated softwater lakes at very low aquatic CO2 concentrations. However, if the sediments contain enough nutrients, a rise in aquatic CO2 could allow the invasion of elodeid species leading to the subsequent disappearance of slow-growing isoetids. [source]

Effects of Deficit Drip Irrigation Ratios on Cotton (Gossypium hirsutum L.) Yield and Fibre Quality

H. Basal
Abstract Increasing irrigation costs and declining water availability compel producers to adapt irrigation strategies for maximum crop yield and water use efficiency. A field trial was conducted to observe the effects of various drip irrigation ratios (IR-0, IR-25, IR-50, IR-75 and IR-100) on water use efficiency (WUE), the irrigation water use efficiency (IWUE), lint yield, yield components and fibre quality at two upland cotton varieties during 2004 and 2005. WUE was found to increase from 0.62 to 0.71 kg m,3 as the irrigation water applied was reduced from 100 % to 75 % of soil water depletion. Deficit irrigation of cotton with drip irrigation at 75 % treatment level (IR-75) did not decrease seed cotton yield and yield components during 2 years, with the exception of the number of bolls in 2005. Among fibre quality parameters, no significant differences in fibre length, fineness, uniformity index and elongation were detected between the 100 % and 75 % irrigation levels in 2005. The results revealed that irrigation of cotton with a drip irrigation method at 75 % level had significant benefits in terms of saved irrigation water without reducing yield, and high WUE indicated a definitive advantage of employing deficit irrigation under limited water supply conditions. [source]

Silicon-mediated resistance of sugarcane to Eldana saccharina Walker (Lepidoptera: Pyralidae): effects of silicon source and cultivar

M. G. Keeping
Abstract:, The effects of four silicon sources , a USA calcium silicate, a local (South African) calcium silicate, Slagment® and fly ash , on the resistance of sugarcane cultivars (two resistant and two susceptible) to Eldana saccharina Walker (Lepidoptera: Pyralidae) were studied in a potted sugarcane trial. Silicon sources were applied at 5000 or 10 000 kg/ha for the calcium silicates and Slagment; fly ash was applied at 15 000 or 30 000 kg/ha. The greatest increase in plant silicon content (particularly in stalks) was recorded for plants treated with local calcium silicate. Silicon uptake did not vary significantly between the susceptible and resistant cultivars, although the resistant cultivars had inherently higher silicon content than the susceptible ones. Treatment with silicon significantly reduced borer damage and borer performance at the higher treatment level. In general, borer damage and performance decreased with increasing rates of applied silicon and both variables were inversely related with per cent stalk silicon. On average, the higher silicon rate reduced damage by 34% in the susceptible cultivars and by 26% in the resistant cultivars, supporting the argument that susceptible cultivars benefit more from silicon treatments than resistant ones. We propose that calcium silicate amendments could be employed in the integrated, area-wide management of E. saccharina and in the management of soil acidity, both of which are widespread problems in the South African sugar industry. [source]

Fund allocation within Australian dental care: an innovative approach to output based funding

M. Tennant
Abstract Background: Over the last 15 years in Australia the process of funding government health care has changed significantly. The development of dental funding models that transparently meet both the service delivery needs for data at the treatment level and policy makers' need for health condition data is critical to the continued integration of dentistry into the wider health system. Methods: This paper presents a model of fund allocation that provides a communication construct that addresses the needs of both policy makers and service providers. Results: In this model, dental treatments (dental item numbers) have been grouped into eight broad dental health conditions. Within each dental health condition, a weighted average price is determined using the Department of Veterans Affairs' (DVA) fee schedule as the benchmark, adjusted for the mix of care. The model also adjusts for the efficiency differences between sectors providing government funded dental care. In summary, the price to be applied to a dental health condition category is determined by the weighted average DVA price adjusted by the sector efficiency. Conclusions: This model allows governments and dental service providers to develop funding agreements that both quantify and justify the treatment to be provided. Such a process facilitates the continued integration of dental care into the wider health system. [source]

Qualitative Data Collection and Analysis Methods: The INSTINCT Trial

William J. Meurer MD
Patient care practices often lag behind current scientific evidence and professional guidelines. The failure of such knowledge translation (KT) efforts may reflect inadequate assessment and management of specific barriers confronting both physicians and patients at the point of treatment level. Effective KT in this setting may benefit from the use of qualitative methods to identify and overcome these barriers. Qualitative methodology allows in-depth exploration of the barriers involved in adopting practice change and has been infrequently used in emergency medicine research. The authors describe the methodology for qualitative analysis within the INcreasing Stroke Treatment through INteractive behavioral Change Tactics (INSTINCT) trial. This includes processes for valid data collection and reliable analysis of the textual data from focus group and interview transcripts. INSTINCT is a 24-hospital, randomized, controlled study that is designed to evaluate a system-based barrier assessment and interactive educational intervention to increase appropriate tissue plasminogen activator (tPA) use in ischemic stroke. Intervention hospitals undergo baseline barrier assessment using both qualitative as well as quantitative (survey) techniques. Investigators obtain data on local barriers to tPA use, as well as information on local attitudes, knowledge, and beliefs regarding acute stroke treatment. Targeted groups at each site include emergency physicians, emergency nurses, neurologists, radiologists, and hospital administrators. Transcript analysis using NVivo7 with a predefined barrier taxonomy is described. This will provide both qualitative insight on thrombolytic use and importance of specific barrier types for each site. The qualitative findings subsequently direct the form of professional education efforts and system interventions at treatment sites. [source]

Impact of spinosad on ichneumonid-parasitized Choristoneura rosaceana larvae and subsequent parasitoid emergence

J.E. Cossentine
Abstract The impact of low levels of spinosad on the obliquebanded leafroller, Choristoneura rosaceana Harris (Lepidoptera: Tortricidae), and the koinobiont endoparasitoid, Apophua simplicipes Cresson (Hymenoptera: Ichneumonidae), was assessed when the parasitoid was in the larval stage within second- and fourth-instar hosts. These are developmental stages that would be exposed to spring orchard treatments of the insecticide. Oral spinosad LC50 levels for unparasitized obliquebanded leafroller hosts were <1% of the recommended orchard treatment levels. Apophua simplicipes survival was significantly reduced within parasitized spinosad-treated second- and fourth-instar larval hosts. Both the leafroller host and parasitoid were much more susceptible (ca. 65-fold) to spinosad when larval hosts fed on spinosad-treated leaf material as opposed to being treated topically. When hosts were exposed to extremely low doses of spinosad, a small percentage of parasitoids was able to survive to emerge as adults. These laboratory trials predict that applications of spinosad may reduce biological control of C. rosaceana populations by ichneumonid endoparasitoids developing within treated hosts. [source]

Effects of lambda-cyhalothrln in two ditch microcosm systems of different trophic status

Ivo Roessink
Abstract The fate and effects of the pyrethroid insecticide lambda-cyhalothrin were compared in mesotrophic (macrophyte-dominated) and eutrophic (phytoplankton-dominated) ditch microcosms (,0.5 m3). Lambda-cyhalothrin was applied three times at one-week intervals at concentrations of 10, 25, 50, 100, and 250 ng/L. The rate of dissipation of lambda-cyhalothrin in the water column of the two types of test systems was similar. After 1 d, only 30% of the amount applied remained in the water phase. Initial, direct effects were observed primarily on arthropod taxa. The most sensitive species was the phantom midge (Chaoborus obscuripes). Threshold levels for slight and transient direct toxic effects were similar (10 ng/L) between types of test systems. At treatment levels of 25 ng/L and higher, apparent population and community responses occurred. At treatments of 100 and 250 ng/L, the rate of recovery of the macroinvertebrate community was lower in the macrophyte-dominated systems, primarily because of a prolonged decline of the amphipod Gammarus pulex. This species occurred at high densities only in the macrophyte-dominated enclosures. Indirect effects (e.g., increase of rotifers and microcrustaceans) were more pronounced in the plankton-dominated test systems, particularly at treatment levels of 25 ng/L and higher. [source]

UV-B radiation constrains the photosynthesis of Quercus robur through impacts on the abundance of Microsphaera alphitoides

By K. K. Newsham
Summary Quercus robur saplings were exposed at an outdoor facility in the UK to supplemental levels of UV-B radiation (280,315 nm) under arrays of cellulose diacetate-filtered fluorescent lamps which also produced UV-A radiation (315,400 nm). Saplings were also exposed to supplemental UV-A radiation under arrays of polyester-filtered lamps and to ambient levels of solar radiation under arrays of unenergized lamps. The UV-B treatment was modulated to maintain a 30% elevation above the ambient level of erythemally weighted UV-B radiation. Naturally occurring infections by oak powdery mildew (Microsphaera alphitoides) were more abundant, and developed more rapidly, on lammas leaves of saplings which were exposed to treatment levels of UV-B radiation than on leaves of saplings exposed to supplemental UV-A or to ambient levels of solar radiation over 12 weeks in summer and autumn 1996. An analysis of leaf photosynthetic capacities revealed that M. alphitoides infection reduced the quantum efficiency of photosystem (PS) II by 14% at moderate irradiance. Although there was no direct effect of UV-B radiation on PSII photochemistry, exposure of saplings to supplemental UV-A radiation under polyester-filtered lamps resulted in a 17.5% decrease in PSII quantum efficiency, compared with saplings exposed to ambient solar radiation. The results from our study suggest that photosynthesis of Q. robur may be constrained by exposure to UV-B radiation in the natural environment through impacts on the abundance of M. alphitoides. [source]

Responses of dryland soil respiration and soil carbon pool size to abrupt vs. gradual and individual vs. combined changes in soil temperature, precipitation, and atmospheric [CO2]: a simulation analysis

Abstract With the large extent and great amount of soil carbon (C) storage, drylands play an important role in terrestrial C balance and feedbacks to climate change. Yet, how dryland soils respond to gradual and concomitant changes in multiple global change drivers [e.g., temperature (Ts), precipitation (Ppt), and atmospheric [CO2] (CO2)] has rarely been studied. We used a process-based ecosystem model patch arid land simulator to simulate dryland soil respiration (Rs) and C pool size (Cs) changes to abrupt vs. gradual and single vs. combined alterations in Ts, Ppt and CO2 at multiple treatment levels. Results showed that abrupt perturbations generally resulted in larger Rs and had longer differentiated impacts than did gradual perturbations. Rs was stimulated by increases in Ts, Ppt, and CO2 in a nonlinear fashion (e.g., parabolically or asymptotically) but suppressed by Ppt reduction. Warming mainly stimulated heterotrophic Rs (i.e., Rh) whereas Ppt and CO2 influenced autotrophic Rs (i.e., Ra). The combined effects of warming, Ppt, and CO2 were nonadditive of primary single-factor effects as a result of substantial interactions among these factors. Warming amplified the effects of both Ppt addition and CO2 elevation whereas Ppt addition and CO2 elevation counteracted with each other. Precipitation reduction either magnified or suppressed warming and CO2 effects, depending on the magnitude of factor's alteration and the components of Rs (Ra or Rh) being examined. Overall, Ppt had dominant influence on dryland Rs and Cs over Ts and CO2. Increasing Ppt individually or in combination with Ts and CO2 benefited soil C sequestration. We therefore suggested that global change experimental studies for dryland ecosystems should focus more on the effects of precipitation regime changes and the combined effects of Ppt with other global change factors (e.g., Ts, CO2, and N deposition). [source]

Latest news and product developments

PRESCRIBER, Issue 2 2007
Article first published online: 1 MAR 200
Venlafaxine: same suicide risk Venlafaxine (Efexor) is probably not associated with a higher risk of suicide than citalopram, fluoxetine or dosulepin, even when prescribed for patients at higher risk, according to an analysis of the UK General Practice Research Database (BMJ, doi:10.1136/bmj.39041.445104.BE. Published 12 December 2006). The retrospective cohort study found that venlafaxine was associated with a significantly higher risk of completed and attempted suicide in adults than the other antidepressants but, after adjusting for risk factors, the authors concluded that much, if not all, of the difference could be explained by confounding. Raised glucose with thiazides not clinically significant? A new analysis of the ALLHAT trial suggests that the small increase in blood glucose levels associated with long-term thiazide therapy is not associated with an increased risk of cardiovascular events (Arch Intern Med 2006;166:2191-201). The ALLHAT trial compared cardiovascular outcomes in over 18 000 patients with hypertension who were treated with chlortali- done (Hygroton), amlodipine and lisinopril. After two years, fasting blood glucose had increased in all groups (by 0.47, 0.31 and 0.19mmol per litre respectively); compared with chlortalidone, the odds of developing diabetes were 45 per cent lower with lisinopril and 27 per cent lower with amlodipine. However, there was no significant link between fasting blood glucose levels and cardiovascular events, end-stage renal disease or death; developing diabetes was associated with an increased risk of CHD overall but this was not statistically significant for chlortalidone in particular. Withdrawing alendronate after five years' treatment Discontinuing treatment of osteoporosis with alendronate after five years does not significantly increase fracture risk for many women, a US study has shown (J Am Med Assoc 2006;296:2927-38). In this five-year extension to the Fracture Intervention Trial, 1099 women who had taken alendronate for five years were randomised to continue treatment or switch to placebo for a further five years. In those taking placebo, bone mineral density decreased by 2.4 per cent at the hip and 3.7 per cent in the spine but remained above pre- treatment levels. Continuing with alendronate was associated with a lower risk of clinical vertebral fractures (2.4 vs 5.3 per cent) but no significant reduction in morphometric vertebral fractures (9.8 vs 11.3 per cent respectively). The cumulative risk of nonvertebral fractures was 19 per cent in each group. The authors conclude that women at very high risk of clinical vertebral fractures may benefit from continuing alendronate, but for many discontinuation does not appear to increase fracture risk. Instructions on labels Patients with low levels of literacy are at high risk of not understanding medicines labelling (Ann Intern Med 2006;145:887-94). In 395 English-speaking adults, 71 per cent correctly repeated simple label instructions, but only 35 per cent could demonstrate the correct number of tablets involved. Low literacy levels were associated with a twofold increased risk of misunderstanding labelling. Statins campaign The National Prescribing Centre (NPC) has launched a campaign to increase prescribing of low-cost statins. Resources available from its website at are divided into four categories: policy and guidance, therapeutics, implementation resources and monitoring tools. Formats include documents and case studies, Powerpoint presentations and E-learning workshops. patients feeling rested on waking and daytime functioning. The Z-drugs were also believed to cause fewer adverse effects. GPs believe in ,Z' drugs A survey of GPs in Lincolnshire has revealed that their beliefs about nonbenzodiazepine hypnotics are inconsistent with NICE guidance and published evidence (Br J Gen Pract 2006; 56:964-7). Responders believed that zaleplon (Sonata), zopiclone and zolpidem were superior to benzodiazepines in increasing sleep time, patients feeling rested on waking and daytime functioning. The Z-drugs were also believed to cause fewer adverse effects. The authors note that, while benzodiazepine prescribing is declining, that of the Z-drugs is increasing, and they suggest this may be explained by misplaced beliefs about their relative effectiveness and safety. Pharmacy EHC guidance Pharmacists can supply emergency hormonal contraception (EHC) in advance but should consider when it is clinically appropriate to do so, according to revised guidance from the Royal Pharmaceutical Society. The move follows support for advance supply from the British Pregnancy Advisory Service and Marie Stopes International. Pharmacists are advised to decline repeated requests and recommend contraception instead, and to counsel users on using EHC safely and appropriately. More support from NICE NICE has developed two databases to support implementation of its recommendations. The shared learning database ( sharedlearning) includes experiences of implementing NICE guidance. The second, known as ERNIE (Evaluation and Review of NICE Implementation Evidence), includes data provided by NICE on uptake of its advice and external information ( Mental health briefings The DoH ( has published several briefing documents to explain the main changes to mental health legislation, covering professional roles, criteria for detention and supervised community treatment (SCT). SCT applies to patients with a stable chronic mental disorder who have been discharged from hospital and who, but for their treatment, may pose a risk to themselves or others. Patients remain the responsibility of the mental health team. Copyright © 2007 Wiley Interface Ltd [source]

Does concept-mapping strategy work for everyone?

The levels of generativity, learners' self-regulated learning skills
The purpose of this study was to examine the effect of concept-mapping strategies with three different generativity levels (expert-generated concept map, partially learner-generated concept map, fully learner-generated concept map) on knowledge acquisition. Interaction between learners' self-regulated learning (SRL) skills and different levels of generativity was also tested. One hundred twenty-four undergraduate students, randomly assigned to three different concept-mapping groups, were differentiated by high and low levels of SRL skills. The findings suggest that the participants in the fully learner-generated map group significantly outperformed the participants in the expert-generated map group, and participants with high SRL skills significantly outperformed those with low SRL skills across all treatment levels. [source]