561 research outputs found
ELECTROCHEMICAL BEHAVIOR AND ANALYSIS OF MONURON HERBICIDE IN WATER USING VOLTAMMETRIC METHODS AND PRE ACTIVATED CARBON PASTE ELECTRODE
This research work dealt with the electrochemical behavior and voltammetric analysis of monuron, a phenyl urea herbicide. The sensitive enhancement of the monuron electrochemical signal, using a pre-activated carbon paste electrode, and the explanation of its mechanism were the main findings of this study. Unlike most used herbicides (linuron, diuron, fenuron, etc), monuron was rarely studied before by electrochemical methods. Indeed the square wave voltammetry allowed to optimize and to analyze monuron in water samples; the results showed two linear ranges of concentration: from 1.98 to 0.39 ”g mL-1 and from 0.35 to 0.08 ”g mL-1, with detection and quantification limits of LOD= 0.016 ”g mL-1 and LOQ= 0.054”g mL-1 respectively. Besides these quantitative results, the anodic oxidation of monuron has been explained by an irreversible adsorption-controlled process, following a âone electron â one protonâ mechanism
Fredholm-Volterra integral equation of the first kind with potential kernel
A series method is used to separate the variables of position and time for the Fredholm-Volterra integral equation of the first kind and the solution of the system in L_2 [0,1] Ă C[0,T], 0 †t †T < â is obtained, the Fredholm integral equation is discussed using Krein's method. The kernel is written in a Legendre polynomial form. Some important relations are also, established and discussed
Evaluation of the Workplace Environment in the UK, and the Impact on Usersâ Levels of Stimulation
The purpose of this study is to evaluate a number of recently completed workplaces in the UK. The first aim is to assess the impact of various aspects of the workplace environment on usersâ levels of stimulation. The body of previous research undertaken into the workplace environment, identified the aspects to be investigated. Samples of employees from the sixteen businesses were surveyed to determine their perceptions of the workplaces. The results were entered into a regression analysis, and the most significant predictors of perceived stimulation identified. The data also revealed a dramatic reduction in staff arousal levels from mornings to afternoons. Thus, there is a second aim to determine whether changes to significant aspects of the workplace environment during the day can counteract the reduction in usersâ stimulation. Two further workplaces were studied to enable changes to be made over a 12-week period. A sample of employees completed questionnaires, and semi-structured interviews revealed the reasons behind the results. It was found that provision of artwork, personal control of temperature and ventilation and regular breaks were the most significant contributions to increasing stimulation after lunch; while user choice of layout, and design and dĂ©cor of workspaces and break areas, were the most significant aspects at design stage
The proton radius puzzle
High-precision measurements of the proton radius from laser spectroscopy of
muonic hydrogen demonstrated up to six standard deviations smaller values than
obtained from electron-proton scattering and hydrogen spectroscopy. The status
of this discrepancy, which is known as the proton radius puzzle will be
discussed in this paper, complemented with the new insights obtained from
spectroscopy of muonic deuterium.Comment: Moriond 2017 conference, 8 pages, 4 figure
Assessing the effectiveness of the Ramsar Convention in preserving wintering waterbirds in the Mediterranean
lthough biological conservation is based on international agreements, its effectiveness depends on how countries implement such recommendations as effective conservation tools. The Ramsar Convention is the oldest international treaty for wetland and waterbird conservation, establishing the world's largest network of protected areas. However, since it does not constitute any binding measure, its effectiveness in protecting wintering waterbird populations at an international scale has been questioned. Here, we use long-term (1991â2012) count data to assess the effectiveness of the Ramsar Convention in the Mediterranean Basin. We compared abundance and temporal trends of 114 waterbird species between 251 Ramsar wetlands and 3486 non-Ramsar wetlands. We found that the Ramsar network is critical for wintering waterbirds, concentrating nearly half of all waterbirds counted in the Mediterranean Basin in only 7% of monitored wetlands. Waterbird trends followed a northwestsoutheast gradient, with a population decrease in the East. A significant and positive Ramsar effect on population trends was only found for the species of higher conservation concern in the Maghreb, particularly when a management plan was implemented. The Ramsar Convention was previously used on very important wetlands for waterbirds in Southern Europe, but is now an underused conservation tool. Our study suggests weaknesses in the use of Ramsar as an effective conservation tool in most of the Mediterranean Basin. However, the Ramsar Convention effectiveness to enhance waterbird populations in the Maghreb should encourage strengthening the Ramsar Convention. It should be done particularly in countries with limited environmental agreements and by systematic implementation of management plans. Conservation measures International conventions Protected areas Protection status Monitoring WetlandsacceptedVersio
Two in one sweep: aluminum tolerance and grain yield in P-limited soils are associated to the same genomic region in West African Sorghum
Background
Sorghum (Sorghum bicolor L. Moench) productivity is severely impeded by low phosphorus (P) and aluminum (Al) toxic soils in sub-Saharan Africa and especially West Africa (WA). Improving productivity of this staple crop under these harsh conditions is crucial to improve food security and farmerâs incomes in WA.
Results
This is the first study to examine the genetics underlying sorghum adaptation to phosphorus limitation in a wide range of WA growing conditions. A set of 187 diverse sorghum genotypes were grown in 29 âP andâ+âP field experiments from 2006-2012 in three WA countries. Sorghum grain yield performance under âP andâ+âP conditions was highly correlated (râ=â0.85***). Significant genotype-by-phosphorus interaction was detected but with small magnitude compared to the genotype variance component. We observed high genetic diversity within our panel, with rapid linkage disequilibrium decay, confirming recent sequence based studies in sorghum. Using genome wide association mapping based on 220 934 SNPs we identified one genomic region on chromosome 3 that was highly associated to grain yield production. A major Al-tolerance gene in sorghum, SbMATE, was collocated in this region and SbMATE specific SNPs showed very high associations to grain yield production, especially under âP conditions, explaining up to 16% of the genotypic variance.
Conclusion
The results suggest that SbMATE has a possible pleiotropic role in providing tolerance to two of the most serious abiotic stresses for sorghum in WA, Al toxicity and P deficiency. The identified SNPs can help accelerate breeding for increased sorghum productivity under unfavorable soil conditions and contribute to assuring food security in WA
Search for Relativistic Magnetic Monopoles with IceCube
We present the first results in the search for relativistic magnetic
monopoles with the IceCube detector, a subsurface neutrino telescope located in
the South Polar ice cap containing a volume of 1 km. This analysis
searches data taken on the partially completed detector during 2007 when
roughly 0.2 km of ice was instrumented. The lack of candidate events
leads to an upper limit on the flux of relativistic magnetic monopoles of
\Phi_{\mathrm{90%C.L.}}\sim 3\e{-18}\fluxunits for . This is a
factor of 4 improvement over the previous best experimental flux limits up to a
Lorentz boost below . This result is then interpreted for a
wide range of mass and kinetic energy values.Comment: 11 pages, 11 figures. v2 is minor text edits, no changes to resul
Lateral Distribution of Muons in IceCube Cosmic Ray Events
In cosmic ray air showers, the muon lateral separation from the center of the
shower is a measure of the transverse momentum that the muon parent acquired in
the cosmic ray interaction. IceCube has observed cosmic ray interactions that
produce muons laterally separated by up to 400 m from the shower core, a factor
of 6 larger distance than previous measurements. These muons originate in high
pT (> 2 GeV/c) interactions from the incident cosmic ray, or high-energy
secondary interactions. The separation distribution shows a transition to a
power law at large values, indicating the presence of a hard pT component that
can be described by perturbative quantum chromodynamics. However, the rates and
the zenith angle distributions of these events are not well reproduced with the
cosmic ray models tested here, even those that include charm interactions. This
discrepancy may be explained by a larger fraction of kaons and charmed
particles than is currently incorporated in the simulations
The IceCube Neutrino Observatory Part VI: Ice Properties, Reconstruction and Future Developments
Papers on ice properties, reconstruction and future developments submitted to
the 33nd International Cosmic Ray Conference (Rio de Janeiro 2013) by the
IceCube Collaboration.Comment: 28 pages, 38 figures; Papers submitted to the 33nd International
Cosmic Ray Conference, Rio de Janeiro 2013; version 2 corrects errors in the
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