Multidimensional relativistic MHD simulations of Pulsar Wind Nebulae: dynamics and emission

Pulsar Wind Nebulae, and the Crab nebula in particular, are the best cosmic laboratories to investigate the dynamics of magnetized relativistic outflows and particle acceleration up to PeV energies. Multidimensional MHD modeling by means of numerical simulations has been very successful at reproducing, to the very finest details, the innermost structure of these synchrotron emitting nebulae, as observed in the X-rays. Therefore, the comparison between the simulated source and observations can be used as a powerful diagnostic tool to probe the physical conditions in pulsar winds, like their composition, magnetization, and degree of anisotropy. However, in spite of the wealth of observations and of the accuracy of current MHD models, the precise mechanisms for magnetic field dissipation and for the acceleration of the non-thermal emitting particles are mysteries still puzzling theorists to date. Here we review the methodologies of the computational approach to the modeling of Pulsar Wind Nebulae, discussing the most relevant results and the recent progresses achieved in this fascinating field of high-energy astrophysics.Comment: 29 pages review, preliminary version. To appear in the book "Modelling Nebulae" edited by D. Torres for Springer, based on the invited contributions to the workshop held in Sant Cugat (Barcelona), June 14-17, 201

A first EGRET-UNID-related agenda for the next-generation Cherenkov telescopes

The next generation of Imaging Atmospheric Cherenkov Telescopes (IACTs) will open the regime between approx. 30 GeV and 200 GeV to ground-based gamma observations with unprecedented point source sensitivity and source location accuracy. I examine the prospects of observing the unidentified objects (UNIDs) of the Third EGRET Catalog using the IACT observatories currently under construction by the CANGAROO, HESS, MAGIC and VERITAS collaborations. Assuming a modest spectral steepening similar to that observed in the inverse Compton component of the Crab Nebula spectrum and taking into account the sensitivity of the instruments and its zenith angle dependence, a detailed list of 78 observable objects is derived which is then further constrained to 38 prime candidates. The characteristics of this agenda are discussed.Comment: 21 pages, 5 figures, to be published in Carraminana, Reimer & Thompson (eds.) Proc. "The nature of unidentified high-energy gamma-ray sources (Tonantzintla, Mexico, October 2000)", Kluwer Academi

Population genetics of a lethally managed medium-sized predator

Globally, levels of human–wildlife conflict are increasing as a direct consequence of the expansion of people into natural areas resulting in competition with wildlife for food and other resources. By being forced into increasingly smaller pockets of suitable habitat, many animal species are at risk of becoming susceptible to loss of genetic diversity, inbreeding depression and the associated inability to adapt to environmental changes. Predators are often lethally controlled due to their threat to livestock. Predators such as jackals (black backed, golden and side striped; Canis mesomelas, C. aureus and C. adustus, respectively), red foxes (Vulpes vulpes) and coyotes (C. latrans) are highly adaptable and may respond to ongoing persecution through compensatory reproduction such as reproducing at a younger age, producing larger litters and/or compensatory immigration including dispersal into vacant territories. Despite decades of lethal management, jackals are problematic predators of livestock in South Africa and, although considered a temporary measure, culling of jackals is still common. Culling may affect social groups, kinship structure, reproductive strategies and sex-biased dispersal in this species. Here, we investigated genetic structure, variation and relatedness of 178 culled jackals on private small-livestock farms in the central Karoo of South Africa using 13 microsatellites. Genetic variation was moderate to high and was similar per year and per farm. An absence of genetic differentiation was observed based on STRUCTURE, principal component analysis and AMOVA. Relatedness was significantly higher within farms (r = 0.189) than between farms (r = 0.077), a result corroborated by spatial autocorrelation analysis. We documented 18 occurrences of dispersal events where full siblings were detected on different farms (range: 0.78–42.93 km). Distance between identified parent–offspring varied from 0 to 36.49 km. No evidence for sex-biased dispersal was found. Our results suggest that in response to ongoing lethal management, this population is most likely able to maintain genetic diversity through physiological and behavioural compensation mechanisms.APPENDIX S1. Supplementary methods.SUPPLEMENTARY TABLES. TABLE S1. Primer details for microsatellite loci used to genotype black-backed jackals (Canis Mesomelas). TABLE S2. Per-locus summary statistics as calculated in Cervus v3.0.7. The non-exclusion probabilities and combined non-exclusion probabilities (final row, italics) are relevant indicators of the power of the loci for parentage and sibship analyses. TABLE S3. Summary statistics for 20 sampling localities (farms) with >1 sample and for all farms pooled. Produced using the basicStats command of the diveRsity package v1.9.90 in R v3.6.2 and RStudio v1.2.5033. Standard deviation was calculated across loci in Microsoft Excel (stdev.s). Sampling localities with only one sample are not shown. TABLE S4. Summary statistics per year and for all years pooled. Produced using the basicStats command of the diveRsity package v1.9.90 in R v3.6.2 and RStudio v1.2.5033. Standard deviation was calculated across loci in Microsoft Excel (STDEV.S). TABLE S5. Pairwise FST values between farms with the full dataset (below diagonal) and associated significance at a level of 0.05 (above diagonal), where significant values are indicated by a “+” and non-significant values by a “−”. Calculated in Arlequin 3.5.2.2. TABLE S6. Pairwise FST values between farms with relatives removed (below diagonal) and associated significance at a level of 0.05 (above diagonal), where significant values are indicated by a “+” and non-significant values by a “−”. Calculated in Arlequin 3.5.2.2. TABLE S7. Comparison of mean pairwise relatedness (r) between years and mean individual inbreeding coefficients (F) between years. P-values for the Wilcoxon tests for difference in means are shown on the inside of the table (bordered by grey), with P-values for inbreeding comparisons shown below the diagonal (bottom left) and P-values for relatedness comparisons shown above the diagonal (top right). The mean F for each year is shown in the left-most column “outside” the main table, with the mean r for each year shown in the top row “outside” the main table. The numbers in parentheses after each year are the number of observations/data points for that year (number of samples for F and number of pairwise relatedness comparisons for r).SUPPLEMENTARY FIGURES. FIGURE S1. STRUCTURE HARVESTER results for (a) Delta K values and (b) probability (-LnPr) of K = 1–27 averaged over 20 runs and (c) genetic differentiation between the jackal sample locations (farms) based on STRUCTURE analysis (performed with K = 2–6) of 1 = GV, 2 = BB, 3 = BR, 4 = BD, 5 = DS, 6 = GG, 7 = HK, 8 = KD, 9 = KW, 10 = KK, 11 = KT, 12 = NG, 13 = ND, 14 = OG, 15 = RV, 16 = RE, 17 = RT, 18 = RD, 19 = SG, 20 = SK, 21 = VR, 22 = WK, 23 = CL, 24 = KR, 25 = WB and 26 = TD. FIGURE S2. STRUCTURE HARVESTER results for (a) Delta K values and (b) probability (-LnPr) of K = 1–27 averaged over 20 runs and (c) genetic differentiation between the jackal sample locations (farms) based on STRUCTURE analysis (performed with K = 2–6 and K = 14) of 1 = GV, 2 = BB, 3 = BD, 4 = DS, 5 = GG, 6 = HK, 7 = KW, 8 = KT, 9 = NG, 10 = ND, 11 = OG, 12 = RV, 13 = RE, 14 = RD, 15 = SG, 16 = SK, 17 = VR, 18 = WK and 19 = CL. After removing relatives, some localities had no samples, hence fewer sampling localities as compared to the full dataset. Note: The Evanno method (DeltaK) does not evaluate K = 1. FIGURE S3. Principal component analysis (PCA) of the different jackal sampling locations (farms) with related individuals removed. FIGURE S4. Plot comparing the relatedness estimates using six estimators and simulated individuals of known relatedness. Di, Dyadic likelihood estimator “DyadML”; LL, Lynch-Li estimator; LR, Lynch and Ritland estimator; QG, Queller and Goodnight estimator; Tri, Triadic likelihood estimator “TrioML”; W, Wang estimator. Plot produced with ggplot2 3.3.0 (Wickham, 2016). FIGURE S5. Results of the spatial autocorrelation analysis for A females and B males. The blue line indicates the autocorrelation coefficient of the data, with the 95% confidence interval at each distance class indicated by the black error bars, as determined by 1000 bootstrap resampling replicates. The red dashed lines indicate the 95% confidence interval around the null hypothesis (no spatial structure, i.e. rauto = 0), as determined by permutation (999 steps). Thus, if the error bars around the blue line do not overlap with the red dashed lines in a distance class, then genotypes were more (positive rauto) or less (negative rauto) similar than expected under the null hypothesis in that distance class. Such cases are indicated with an asterisk (*).The National Zoological Gardens, Pretoria and the University of South Africa.https://zslpublications.onlinelibrary.wiley.com/journal/14697998hj2023BiochemistryGeneticsMicrobiology and Plant Patholog

Bedrijfstoeslagen en maatschappelijke waarden in Nederland : een verkenning van opties

In deze studie zijn vier opties doorberekend over de mogelijkheden om bedrijfstoeslagen te verbinden met maatschappelijke waarden, in dit geval natuur, milieu en landschap. De onderzochte effecten betreffen naast natuur, landschap en milieu ook de inkomens, toegevoegde waarde en werkgelegenheid van betrokken agrarische bedrijven, sectoren, regio's en agroketens en de uitvoerbaarheid van de onderzochte maatregelen (zoals genoemd in de houtskoolschets van LNV). Bij de uitvoering van deze studie zijn modellen van diverse instituten meegenome

Implications of H.E.S.S. observations of pulsar wind nebulae

In this review paper on pulsar wind nebulae (PWN) we discuss the properties of such nebulae within the context of containment against cross-field diffusion (versus normal advection), the effect of reverse shocks on the evolution of offset ``Vela-like'' PWN, constraints on maximum particle energetics, magnetic field strength estimates based on spectral and spatial properties, and the implication of such field estimates on the composition of the wind. A significant part of the discussion is based on the High Energy Stereoscopic System ({\it H.E.S.S.} or {\it HESS}) detection of the two evolved pulsar wind nebulae Vela X (cocoon) and HESS J1825-137. In the case of Vela X (cocoon) we also review evidence of a hadronic versus a leptonic interpretation, showing that a leptonic interpretation is favored for the {\it HESS} signal. The constraints discussed in this review paper sets a general framework for the interpretation of a number of offset, filled-center nebulae seen by {\it HESS}. These sources are found along the galactic plane with galactic latitudes $|b|\sim 0$, where significant amounts of molecular gas is found. In these regions, we find that the interstellar medium is inhomogeneous, which has an effect on the morphology of supernova shock expansion. One consequence of this effect is the formation of offset pulsar wind nebulae as observed.Comment: to appear in Springer Lecture Notes on Neutron Stars and Pulsars: 40 years after their discovery, eds. W. Becke

Malnutrition assessment methods in adult patients with tuberculosis:A systematic review

OBJECTIVES: Malnutrition is associated with a twofold higher risk of dying in patients with tuberculosis (TB) and considered an important potentially reversible risk factor for failure of TB treatment. The construct of malnutrition has three domains: intake or uptake of nutrition; body composition and physical and cognitive function. The objectives of this systematic review are to identify malnutrition assessment methods, and to quantify how malnutrition assessment methods capture the international consensus definition for malnutrition, in patients with TB. DESIGN: Different assessment methods were identified. We determined the extent of capturing of the three domains of malnutrition, that is, intake or uptake of nutrition, body composition and physical and cognitive function. RESULTS: Seventeen malnutrition assessment methods were identified in 69 included studies. In 53/69 (77%) of studies, body mass index was used as the only malnutrition assessment method. Three out of 69 studies (4%) used a method that captured all three domains of malnutrition. CONCLUSIONS: Our study focused on published articles. Implementation of new criteria takes time, which may take longer than the period covered by this review. Most patients with TB are assessed for only one aspect of the conceptual definition of malnutrition. The use of international consensus criteria is recommended to establish uniform diagnostics and treatment of malnutrition. PROSPERO REGISTRATION NUMBER: CRD42019122832

Prognostic Impact of HER2 and ER Status of Circulating Tumor Cells in Metastatic Breast Cancer Patients with a HER2-Negative Primary Tumor

BACKGROUND: Preclinical and clinical studies have reported that human epidermal growth factor receptor 2 (HER2) overexpression yields resistance to endocrine therapies. Here the prevalence and prognostic impact of HER2-positive circulating tumor cells (CTCs) were investigated retrospectively in metastatic breast cancer (MBC) patients with a HER2-negative primary tumor receiving endocrine therapy. Additionally, the prevalence and prognostic significance of HER2-positive CTCs were explored in a chemotherapy cohort, as well as the prognostic impact of the estrogen receptor (ER) CTC status in both cohorts. METHODS: Included were MBC patients with a HER2-negative primary tumor, with ≥1 detectable CTC, starting a new line of treatment. CTCs were enumerated using the CellSearch system, characterized for HER2 with the CellSearch anti-HER2 phenotyping reagent, and characterized for ER mRNA expression. Primary end point was pr

UV and EUV Instruments

We describe telescopes and instruments that were developed and used for astronomical research in the ultraviolet (UV) and extreme ultraviolet (EUV) regions of the electromagnetic spectrum. The wavelength ranges covered by these bands are not uniquely defined. We use the following convention here: The EUV and UV span the regions ~100-912 and 912-3000 Angstroem respectively. The limitation between both ranges is a natural choice, because the hydrogen Lyman absorption edge is located at 912 Angstroem. At smaller wavelengths, astronomical sources are strongly absorbed by the interstellar medium. It also marks a technical limit, because telescopes and instruments are of different design. In the EUV range, the technology is strongly related to that utilized in X-ray astronomy, while in the UV range the instruments in many cases have their roots in optical astronomy. We will, therefore, describe the UV and EUV instruments in appropriate conciseness and refer to the respective chapters of this volume for more technical details.Comment: To appear in: Landolt-Boernstein, New Series VI/4A, Astronomy, Astrophysics, and Cosmology; Instruments and Methods, ed. J.E. Truemper, Springer-Verlag, Berlin, 201

The position of graptolites within Lower Palaeozoic planktic ecosystems.

An integrated approach has been used to assess the palaeoecology of graptolites both as a discrete group and also as a part of the biota present within Ordovician and Silurian planktic realms. Study of the functional morphology of graptolites and comparisons with recent ecological analogues demonstrates that graptolites most probably filled a variety of niches as primary consumers, with modes of life related to the colony morphotype. Graptolite coloniality was extremely ordered, lacking any close morphological analogues in Recent faunas. To obtain maximum functional efficiency, graptolites would have needed varying degrees of coordinated automobility. A change in lifestyle related to ontogenetic changes was prevalent within many graptolite groups. Differing lifestyle was reflected by differing reproductive strategies, with synrhabdosomes most likely being a method for rapid asexual reproduction. Direct evidence in the form of graptolithophage 'coprolitic' bodies, as well as indirect evidence in the form of probable defensive adaptations, indicate that graptolites comprised a food item for a variety of predators. Graptolites were also hosts to a variety of parasitic organisms and provided an important nutrient source for scavenging organisms