3,206 research outputs found
Xanthomonas campestris pv. campestris race 1 is the main causal agent of black rot of Brassicas in Southern Mozambique
Severe outbreaks of bacterial black rot caused by Xanthomonas campestris pv. campestris (Xcc) were observed in Brassica production fields of Southern Mozambique. The causal agent of the disease in the Mahotas and ChòkwÊ districts was identified and characterised. In total, 83 Xanthomonas-like strains were isolated from seed samples and leaves of cabbage and tronchuda cole with typical symptoms of the disease. Forty-six out of the 83 strains were found to be putative Xcc in at least one of the tests used: Classical biochemical assays, enzyme-linked immunosorbent assay (ELISA) with monoclonal antibodies, Biolog identification system, polymerase chain reaction (PCR) with specific primers and pathogenicity tests. The ELISA tests were positive for 43 strains. Biolog identified 43 strains as Xanthomonas, but only 32 as Xcc. PCR tests with primers targeting a fragment of the hrpF gene were positive for all 46 strains tested. Three strains were not pathogenic or weakly pathogenic and all other strains caused typical black rot symptoms in brassicas. Race type differentiation tests revealed the Xcc strains from Mozambique as members of race 1. The prevalence of this pathogenic race of the Xcc pathogen in Mozambique should be considered when black rot resistant cultivars are evaluated or introduced into the production regions of this country
Estimation of Density-Dependent Mortality of Juvenile Bivalves in the Wadden Sea
We investigated density-dependent mortality within the early months of life of the bivalves Macoma balthica (Baltic tellin) and Cerastoderma edule (common cockle) in the Wadden Sea. Mortality is thought to be density-dependent in juvenile bivalves, because there is no proportional relationship between the size of the reproductive adult stocks and the numbers of recruits for both species. It is not known however, when exactly density dependence in the pre-recruitment phase occurs and how prevalent it is. The magnitude of recruitment determines year class strength in bivalves. Thus, understanding pre-recruit mortality will improve the understanding of population dynamics. We analyzed count data from three years of temporal sampling during the first months after bivalve settlement at ten transects in the Sylt-Rømø-Bay in the northern German Wadden Sea. Analyses of density dependence are sensitive to bias through measurement error. Measurement error was estimated by bootstrapping, and residual deviances were adjusted by adding process error. With simulations the effect of these two types of error on the estimate of the density-dependent mortality coefficient was investigated. In three out of eight time intervals density dependence was detected for M. balthica, and in zero out of six time intervals for C. edule. Biological or environmental stochastic processes dominated over density dependence at the investigated scale
Xanthomonas campestris pv. campestris race 1 is the main causal agent of black rot of Brassicas in Southern Mozambique
Severe outbreaks of bacterial black rot caused by Xanthomonas campestris pv. campestris (Xcc) were observed in Brassica production fields of Southern Mozambique. The causal agent of the disease in the Mahotas and ChòkwÊ districts was identified and characterised. In total, 83 Xanthomonas-like strains were isolated from seed samples and leaves of cabbage and tronchuda cole with typical symptoms of the disease. Forty-six out of the 83 strains were found to be putative Xcc in at least one of the tests used: Classical biochemical assays, enzyme-linked immunosorbent assay (ELISA) with monoclonal antibodies, Biolog identification system, polymerase chain reaction (PCR) with specific primers and pathogenicity tests. The ELISA tests were positive for 43 strains. Biolog identified 43 strains as Xanthomonas, but only 32 as Xcc. PCR tests with primers targeting a fragment of the hrpF gene were positive for all 46 strains tested. Three strains were not pathogenic or weakly pathogenic and all other strains caused typical black rot symptoms in brassicas. Race type differentiation tests revealed the Xcc strains from Mozambique as members of race 1. The prevalence of this pathogenic race of the Xcc pathogen in Mozambique should be considered when black rot resistant cultivars are evaluated or introduced into the production regions of this country.Keywords: Cole crops, cabbage, tronchuda, landraces, seeds, black rot, enzyme-linked immunosorbent assay (ELISA), Biolog, polymerase chain reaction (PCR), race-typeAfrican Journal of Biotechnology Vol. 12(6), pp. 602-61
Intra-week spatial-temporal patterns of crime
Since its original publication, routine activity theory has proven most instructive for understanding temporal patterns in crime. The most prominent of the temporal crime patterns investigated is seasonality: crime (most often assault) increases during the summer months and decreases once routine activities are less often outside. Despite the rather widespread literature on the seasonality of crime, there is very little research investigating temporal patterns of crime at shorter time intervals such as within the week or even within the day. This paper contributes to this literature through a spatial-temporal analysis of crime patterns for different days of the week. It is found that temporal patterns are present for different days of the week (more crime on weekends, as would be expected) and there is a spatial component to that temporal change. Specifically, aside from robbery and sexual assault at the micro-spatial unit of analysis (street segments) the spatial patterns of crime changed. With regard to the spatial pattern changes, we found that assaults and theft from vehicle had their spatial patterns change in predictable ways on Saturdays: assaults increased in the bar district and theft from vehicles increased in the downtown and recreational car park areas
Intracranial Pressure Monitoring: Invasive versus Non-Invasive MethodsâA Review
Monitoring of intracranial pressure (ICP) has been used for decades in the fields of neurosurgery and neurology. There are multiple techniques: invasive as well as noninvasive. This paper aims to provide an overview of the advantages and disadvantages of the most common and well-known methods as well as assess whether noninvasive techniques (transcranial Doppler, tympanic membrane displacement, optic nerve sheath diameter, CT scan/MRI and fundoscopy) can be used as reliable alternatives to the invasive techniques (ventriculostomy and microtransducers). Ventriculostomy is considered the gold standard in terms of accurate measurement of pressure, although microtransducers generally are just as accurate. Both invasive techniques are associated with a minor risk of complications such as hemorrhage and infection. Furthermore, zero drift is a problem with selected microtransducers. The non-invasive techniques are without the invasive methods' risk of complication, but fail to measure ICP accurately enough to be used as routine alternatives to invasive measurement. We conclude that invasive measurement is currently the only option for accurate measurement of ICP
The Presampler for the Forward and Rear Calorimeter in the ZEUS Detector
The ZEUS detector at HERA has been supplemented with a presampler detector in
front of the forward and rear calorimeters. It consists of a segmented
scintillator array read out with wavelength-shifting fibers. We discuss its
desi gn, construction and performance. Test beam data obtained with a prototype
presampler and the ZEUS prototype calorimeter demonstrate the main function of
this detector, i.e. the correction for the energy lost by an electron
interacting in inactive material in front of the calorimeter.Comment: 20 pages including 16 figure
Spatio-temporal crime hotspots and the ambient population
It is well known that, due to that inherent differences in their underlying causal mechanisms, different types of crime will have variable impacts on different groups of people. Furthermore, the locations of vulnerable groups of people are highly temporally dynamic. Hence an accurate estimate of the true population at risk in a given place and time is vital for reliable crime rate calculation and hotspot generation. However, the choice of denominator is fraught with difficulty because data describing popular movements, rather than simply residential location, are limited. This research will make use of new âcrowd-sourcedâ data in an attempt to create more accurate estimates of the population at risk for mobile crimes such as street robbery. Importantly, these data are both spatially and temporally referenced and can therefore be used to estimate crime rate significance in both space and time. Spatio-temporal cluster hunting techniques will be used to identify crime hotspots that are significant given the size of the ambient population in the area at the time
Production of antihydrogen at reduced magnetic field for anti-atom trapping
We have demonstrated production of antihydrogen in a 1T solenoidal
magnetic field. This field strength is significantly smaller than that used in
the first generation experiments ATHENA (3T) and ATRAP (5T). The
motivation for using a smaller magnetic field is to facilitate trapping of
antihydrogen atoms in a neutral atom trap surrounding the production region. We
report the results of measurements with the ALPHA (Antihydrogen Laser PHysics
Apparatus) device, which can capture and cool antiprotons at 3T, and then
mix the antiprotons with positrons at 1T. We infer antihydrogen production
from the time structure of antiproton annihilations during mixing, using mixing
with heated positrons as the null experiment, as demonstrated in ATHENA.
Implications for antihydrogen trapping are discussed
Absolute quantum yield measurements of fluorescent proteins using a plasmonic nanocavity
One of the key photophysical properties of fluorescent proteins that is most difficult to measure is the quantum yield. It describes how efficiently a fluorophore converts absorbed light into fluorescence. Its measurement using conventional methods become particularly problematic when it is unknown how many of the proposedly fluorescent molecules of a sample are indeed fluorescent (for example due to incomplete maturation, or the presence of photophysical dark states). Here, we use a plasmonic nanocavity-based method to measure absolute quantum yield values of commonly used fluorescent proteins. The method is calibration-free, does not require knowledge about maturation or potential dark states, and works on minute amounts of sample. The insensitivity of the nanocavity-based method to the presence of non-luminescent species allowed us to measure precisely the quantum yield of photo-switchable proteins in their on-state and to analyze the origin of the residual fluorescence of protein ensembles switched to the dark state
Decreasing the Peril of Antimicrobial Resistance Through Enhanced Health Literacy in Outpatient Settings: An Underrecognized Approach to Advance Antimicrobial Stewardship
Š 2020, The Author(s). Globally, antimicrobial resistance (AMR) is a serious problem causing 700,000 deaths annually. By 2050, AMR is expected to cause approximately 10 million deaths globally each year if allowed to increase at the present rate. Many individuals have limited knowledge regarding appropriate antibiotic use and AMR. Most antibiotic use occurs in the outpatient setting, with approximately 30% of antibiotics prescribed deemed unnecessary. Antimicrobial stewardship (AMS) is a means to reduce inappropriate antibiotic use and AMR. While existing AMS efforts generally focus on the inpatient setting, a significant gap is present in the outpatient setting. A common theme across various national action plans to reduce AMR is the need for education and awareness. The importance of communicating information in a manner easily comprehended by the patient in addition to productive clinicianâpatient dialogue cannot be overestimated. Enhancing the publicâs and patientsâ AMS health literacy is an underrecognized approach to help address AMR. We describe Four Core Elements of Enhancing AMS Health Literacy in the Outpatient Setting, utilizing the Centers for Disease Control and Preventionâs framework: (1) leadership commitment, (2) intervention/action, (3) tracking/reporting, and (4) education/expertise. We call upon leaders in outpatient settings to embrace this approach to curb inappropriate antimicrobial use
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