1,506 research outputs found
Highly syntenic and yet divergent: a tale of two Theilerias
The published genomic sequences of the two major host-transforming Theileria species of cattle represent a rich resource of information that has allowed novel bioinformatic and experimental studies into these important apicomplexan parasites. Since their publication in 2005, the genomes of T. annulata and T. parva have been utilised for a diverse range of applications, ranging from candidate antigen discovery to the identification of genetic markers for population analysis. This has led to advancements in the quest for a sub-unit vaccine, while providing a greater understanding of variation among parasite populations in the field. The unique ability of these Theileria species to induce host cell transformation is the subject of considerable scientific interest and the availability of full genomic sequences has provided new insights into this area of research. This article reviews the data underlying published comparative analyses, focussing on the general features of gene expression, the major Tpr/Tar multi-copy gene family and a re-examination of the predicted macroschizont secretome. Codon usage between the Theileria species is reviewed in detail, as this underpins ongoing comparative studies investigating selection at the intra- and inter-species level. The TashAT/TpshAT family of genes, conserved between T. annulata and T. parva, encodes products targeted to the host nucleus and has been implicated in contributing to the transformed bovine phenotype. Species-specific expansion and diversification at this critical locus is discussed with reference to the availability, in the near future, of genomic datasets which are based on non-transforming Theileria species
A tale of two sit-bones: The cyclist’s ischial hygroma (Perineal nodular induration)
The ischial hygroma, also known as a perineal nodular induration, is a relatively rare and mostly cycling-specific injury that is often incorrectly diagnosed and managed. Here two cases with divergent managements are described to highlight the spectrum of treatment available to manage this condition. The presentation, assessment and management of two cases of perineal nodular induration are discussed.The management options, namely surgical excision vs conservative management, with saddle pressure mapping highlight that there is no single optimal method and that a multidisciplinary approach should be applied to treat these injuries successfully. Perineal nodular induration should be investigated appropriately to exclude less benign causes of perineal masses. Conservative management and surgical excision can both be successful. Clinicians should be familiar with the assessment and management of this relatively rare but debilitating condition in competitive cyclists.Keywords: cycling, perineal injur
Weed detection in rainfed maize crops using UAV and planetscope imagery
DATA AVAILABILITY STATEMENT : The PlanetScope data were obtained from the Planet website for academic research.Weed invasion of crop fields, such as maize, is a major threat leading to yield reductions
or crop right-offs for smallholder farming, especially in developing countries. A synoptic view and
timeous detection of weed invasions can save the crop. The sustainable development goals (SDGs)
have identified food security as a major focus point. The objectives of this study are to: (1) assess
the precision of mapping maize-weed infestations using multi-temporal, unmanned aerial vehicle
(UAV), and PlanetScope data by utilizing machine learning algorithms, and (2) determine the optimal
timing during the maize growing season for effective weed detection. UAV and PlanetScope satellite
imagery were used to map weeds using machine learning algorithms—random forest (RF) and
support vector machine (SVM). The input features included spectral bands, color space channels, and
various vegetation indices derived from the datasets. Furthermore, principal component analysis
(PCA) was used to produce principal components (PCs) that served as inputs for the classification. In
this study, eight experiments are conducted, four experiments each for UAV and PlanetScope datasets
spanning four months. Experiment 1 utilized all bands with the RF classifier, experiment 2 used all
bands with SVM, experiment 3 employed PCs with RF, and experiment 4 utilized PCs with SVM. The
results reveal that PlanetScope achieves accuracies below 49% in all four experiments. The best overall
performance was observed for experiment 1 using the UAV based on the highest mean accuracy
score (>0.88), which included the overall accuracy, precision, recall, F1 score, and cross-validation
scores. The findings highlight the critical role of spectral information, color spaces, and vegetation
indices in accurately identifying weeds during the mid-to-late stages of maize crop growth, with
the higher spatial resolution of UAV exhibiting a higher precision in the classification accuracy than
the PlanetScope imagery. The most optimal stage for weed detection was found to be during the reproductive stage of the crop cycle based on the best F1 scores being indicated for the maize and
weeds class. This study provides pivotal information about the spatial distribution of weeds in maize
fields and this information is essential for sustainable weed management in agricultural activities.The Agricultural Research Council-Natural Resources and Engineering (ARC-NRE), Department of Science and Innovation, Council for Scientific and Industrial Research; the National Research Foundation; the Department of Agriculture, Land Reform and Rural Development (DALRRD); and the University of Pretoria.https://www.mdpi.com/journal/sustainabilityam2024Geography, Geoinformatics and MeteorologySDG-02:Zero HungerSDG-12:Responsible consumption and productio
Primary beam effects of radio astronomy antennas -- II. Modelling the MeerKAT L-band beam
After a decade of design and construction, South Africa's SKA-MID precursor
MeerKAT has begun its science operations. To make full use of the widefield
capability of the array, it is imperative that we have an accurate model of the
primary beam of its antennas. We have taken available L-band full-polarization
'astro-holographic' observations of three antennas and a generic
electromagnetic simulation and created sparse representations of the beams
using principal components and Zernike polynomials. The spectral behaviour of
the spatial coefficients has been modelled using discrete cosine transform. We
have provided the Zernike-based model over a diameter of 10 deg averaged over
the beams of three antennas in an associated software tool (EIDOS) that can be
useful in direction-dependent calibration and imaging. The model is more
accurate for the diagonal elements of the beam Jones matrix and at lower
frequencies. As we get more accurate beam measurements and simulations in the
future, especially for the cross-polarization patterns, our pipeline can be
used to create more accurate sparse representations of MeerKAT beams.Comment: 16 pages, 18 figures. This is a pre-copyedited, author-produced PDF
of an article accepted for publication in MNRAS following peer review. The
version of record [K. M. B. Asad et al., 2021] is available online at:
https://doi.org/10.1093/mnras/stab10
Airborne measurements of aerosol optical properties related to early spring transport of mid-latitude sources into the Arctic
Airborne lidar and in-situ measurements of the aerosol properties were conducted between Svalbard Island and Scandinavia in April 2008. Evidence of aerosol transport from Europe and Asia is given. The analysis of the aerosol optical properties based on a multiwavelength lidar (355, 532, 1064 nm) including volume depolarization at 355 nm aims at distinguishing the role of the different aerosol sources (Siberian wild fires, Eastern Asia and European anthropogenic emissions). Combining, first aircraft measurements, second FLEXPART simulations with a calculation of the PBL air fraction originating from the three different mid-latitude source regions, and third level-2 CALIPSO data products (i.e. backscatter coefficient 532 nm,volume depolarization and color ratio between 1064 and 532 nm in aerosol layers) along the transport pathways, appears a valuable approach to identify the role of the different aerosol sources even after a transport time larger than 4 days. Optical depth of the aerosol layers are always rather small (<4%) while transported over the Arctic and ratio of the total attenuated backscatter (i.e. including molecular contribution) provide more stable result than conventional aerosol backscatter ratio. Above Asia, CALIPSO data indicate more depolarization (up to 15%) and largest color ratio (>0.5) for the northeastern Asia emissions (i.e. an expected mixture of Asian pollution and dust), while low depolarization together with smaller and quasi constant color ratio (≈0.3) are observed for the Siberian biomass burning emissions. A similar difference is visible between two layers observed by the aircraft above Scandinavia. The analysis of the time evolution of the aerosol optical properties revealed by CALIPSO between Asia and Scandinavia shows a gradual decrease of the aerosol backscatter, depolarization ratio and color ratio which suggests the removal of the largest particles in the accumulation mode. A similar study conducted for a European plume has shown aerosol optical properties intermediate between the two Asian sources with color ratio never exceeding 0.4 and moderate depolarization ratio being always less than 8%, i.e. less aerosol from the accumulation mode
Conductance of the single-electron transistor: A comparison of experimental data with Monte Carlo calculations
We report on experimental results for the conductance of metallic
single-electron transistors as a function of temperature, gate voltage and
dimensionless conductance. In contrast to previous experiments our transistor
layout allows for a direct measurement of the parallel conductance and no ad
hoc assumptions on the symmetry of the transistors are necessary. Thus we can
make a comparison between our data and theoretical predictions without any
adjustable parameter. Even for rather weakly conducting transistors significant
deviations from the perturbative results are noted. On the other hand, path
integral Monte Carlo calculations show remarkable agreement with experiments
for the whole range of temperatures and conductances.Comment: 8 pages, 7 figures, revtex4, corrected typos, submitted to PR
Books
Brain work Brain Work and Mental Activity: Quantitative Studies with Radioactive Tracers. Ed. by N. A. Lassen, D. H. Ingvar, M. E. RaicWe and L. Friberg. Pp. 446. Illustrated. Copenhagen: Munksgaard. 1991.Neuroanatomy Neuroanatomy for Medical Students. 2nd ed. By ]. L. Wilkinson. pp. x + 307. illustrated. Oxford: Butterworth Heinemann. 1992.Atherosclerosis Molecular Biology of Atherosclerosis: Proceedings of the 57th European Atherosclerosis Society Meeting. Ed. by M. J. Halpern. Pp. xv + 662. Illustrated. £45. London: John libbey. 1992.Antibiotics Antibiotic Guidelines. By H. J. Koomhof and L. D. Liebowitz. pp. 122. Pretoria: JL van Schaik. 1991.Reproductive medicine Reproduction, Growth and Development. By A. Negro-Vilar and G. perez-Palacios. Pp. xv + 440. illustrated. $162,50. New York: Raven Press. 1991.Obesity research Progress in Obesity Research 1990. Ed. by Y. Oomura, S. Tarui, S. Inoue and T. Shimazu. Pp. xiii + 688. illustrated. £17,50. London: John Libbey. 1991.Epidemiology Fetal and Infant Origins of Adult Disease. Ed. by D.}. P. Barker. Pp. xv + 343. £30. London: BM}. 1992
Frog eat frog: exploring variables influencing anurophagy
Background. Frogs are generalist predators of a wide range of typically small prey items. But descriptions of dietary items regularly include other anurans, such that frogs are considered to be among the most important of anuran predators. However, the only existing hypothesis for the inclusion of anurans in the diet of post-metamorphic frogs postulates that it happens more often in bigger frogs. Moreover, this hypothesis has yet to be tested
A tale of two sit-bones: The cyclist’s ischial hygroma (Perineal nodular induration)
The ischial hygroma or perineal nodular induration is a relatively rare and cycling specific injury that is often incorrectly diagnosed and managed. We highlight two cases with divergent managements to highlight the spectrum of treatment available to manage this rare condition. We describe the presentation, assessment and management of two cases of pernineal nodular induration.
The management (surgical excision vs conservative management with saddle pressure mapping) highlight that there is no single optimal management and a multidisciplinary approach should be applied to treat these injuries successfully. Perineal nodular induration should be investigated appropriately to exclude less benign causes of perineal masses. Both conservative management and surgical excision can be successful. Clinicians should be familiar with assessment and management options for this relatively rare but debilitating condition in competitive cyclists.
 
Cohort profile: biological pathways of risk and resilience in Syrian refugee children (BIOPATH)
The BIOPATH cohort was established to explore the interplay of psychosocial and biological factors in the development of resilience and mental health problems in Syrian refugee children. Based in Lebanon, a middle-income country significantly impacted by the refugee crisis, it is the first such cohort of refugees in the Middle East. Families were recruited from informal tented settlements in the Beqaa region using purposive cluster sampling. At baseline (October 2017–January 2018), N = 3188 individuals participated [n = 1594 child–caregiver dyads; child gender, 52.6% female; mean (SD) age = 11.44 (2.44) years, range = 6–19]. Re-participation rate at 1-year follow-up was 62.8%. Individual interviews were conducted with children and primary caregivers and biological samples collected from children. Measures include: (1) children’s well-being and mental health problems (using tools validated against clinical interviews in a subsample of the cohort); (2) psychosocial risk and protective factors at the level of the individual (e.g. coping strategies), family (e.g. parent–child relationship), community (e.g. collective efficacy), and wider context (e.g. services); (3) saliva samples for genetic and epigenetic (methylation) analyses; (4) hair samples to measure cortisol, dehydroepiandrosterone (DHEA) and testosterone. This cohort profile provides details about sampling and recruitment, data collection and measures, demographic data, attrition and potential bias, key findings on resilience and mental health problems in children and strengths and limitations of the cohort. Researchers interested in accessing data should contact Professor Michael Pluess at Queen Mary University of London, UK (e-mail: [email protected]). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00127-022-02228-8
- …