High frequency surface wave radar demonstrator

High Frequency Surface Wave Radar (HFSWR) is used around the globe for the mapping of sea currents and coastal monitoring of the Exclusive Economic Zone. Decision to build an HF radar at the University of Cape Town (UCT) was made by Daniel O’Hagan and Andrew Wilkinson in February 2015 immediately after seeing a demonstration of the CODAR system at IMT. Their intention was subsequently discussed at several meetings, including a South African Radar Interest Group (SARIG) meeting and one at IMT in order to gauge interest and raise funding. There was both interest (mainly for ocean current monitoring) and scepticism (expressed by CSIR and SARIG members) of the value of HF radar for ship monitoring. This reports the design, construction, test, and evaluation of the UCT HFSWR demonstrator. A modular approach was taken in its design and construction making it easy to replicate and upscale. A pillar of this work is to prove the feasibility of a software defined radar (SDR) based HF radar demonstrator. Every part of the demonstrator was designed and constructed from scratch as UCT had no prior HF activities, and therefore no legacy antennas or components to utilise. A low-cost RF frontend follows the HF antennas, which were also designed for this project. Combined with an SDR platforn known as the Red Pitaya (RP), a complete HF radar demonstrator was assembled and trials were conducted at the UCT rugby field and at the IMT facilities in Simon’s Town. A preliminary assessment of the results reveal the effects of Bragg resonance scatter and detection of two stationary targets (mountains) distinguishable by both range and azimuth. This assessment of the results indicates that the demonstrator is operational

First Insight Into Genetic Diversity of Alpine ibex (Capra ibex) in Slovenia

In Europe, the Alpine ibex (Capra ibex) was on the brink of extinction in the 19th century. Therefore, different conservation measures were implemented, and several reintroductions were made in the Alpine arc, starting from the only surviving population in Gran Paradiso, Italy. An extreme historical bottleneck and additional reintroductions have strongly shaped the genetic make-up of recent populations, resulting in significant genetic drift and profound inbreeding across the species range. To support science-based conservation actions, molecular methods have been increasingly used. However, such analyses did not include populations in Slovenia. We analysed neutral loci (partial fragment of mitochondrial cytochrome b, mtDNA) and the adaptive major histocompatibility complex (MHC DRB exon 2) of the Alpine ibex from both Slovenian populations (Julian and Kamnik-Savinja Alps) to understand how past reintroductions and recent management have affected the genetic diversity of the species. Results showed that both populations are genetically severely depleted, carrying only one mtDNA haplotype and one functional allele for MHC DRB exon 2, Caib-DRB*01. This calls for further conservation actions, including the reintroduction of individuals with different genetic background. However, the Alpine ibex is currently considered a non-native species in Slovenia, which makes conservation actions extremely difficult and threatens the long-term survival of the species. Therefore, scientists and population managers are urging policy/decision makers to change the status of the species to the native one and consequently to allow reintroductions. These appeals are supported by previous archaeological data on the existence of bones assigned to Alpine ibex in the Julian Alps, and evidence of severe genetic depletion in current ibex populations confirmed in this study. PRVI VPOGLED V GENETSKO RAZNOLIKOST ALPSKEGA KOZOROGA (Capra ibex) V SLOVENIJI Izvleček: V Evropi je bil alpski kozorog (Capra ibex) v 19. stoletju na robu izumrtja. Izvajali so se različni ukrepi za njegovo ohranjanje. V alpskem loku je bilo izvedenih več ponovnih naselitev, najprej z edino ohranjeno populacijo v kraju Gran Paradiso v Italiji. Izredna okrnjenost vrste v preteklosti in dodatne ponovne naselitve so močno vplivale na genetsko sestavo populacije, kar je povzročilo znaten genetski zdrs in parjenje v sorodstvu na celotnem območju vrste. V podporo znanstveno utemeljenim ukrepom ohranjanja se vse pogosteje uporabljajo molekularne metode, vendar takšne analize niso vključevale populacij v Sloveniji. Da bi razumeli, kako je ponovno naseljevanje in nedavno upravljanje vplivalo na genetsko raznolikost vrste, smo analizirali nevtralne lokuse (delni fragment mitohondrijskega citokroma b, mtDNA) in adaptivni poglavitni histokompatibilnostni kompleks (MHC DRB ekson 2) alpskega kozoroga iz obeh slovenskih populacij (Julijske in Kamniško-Savinjske Alpe). Rezultati so pokazali, da sta obe populaciji genetsko zelo osiromašeni, saj nosita le en haplotip mtDNA in en funkcionalni alel za MHC DRB ekson 2, Caib-DRB*01. Zato so potrebni nadaljnji ukrepi za ohranjanje, vključno s ponovno naselitvijo živali z drugačnim genetskim ozadjem. Vendar alpski kozorog v Sloveniji trenutno velja za tujerodno vrsto, kar zelo otežuje ukrepe za njegovo ohranitev in ogroža dolgoročno preživetje vrste. Znanstveniki in upravljavci populacij zato pozivajo politike/odločevalce, naj spremenijo status vrste v avtohtono in posledično omogočijo ponovno naselitev. Ti pozivi so podprti s predhodnimi arheološkimi podatki o obstoju kosti alpskega kozoroga v Julijskih Alpah in z dokazi o izraziti genetski osiromašenosti sedanjih populacij kozoroga, potrjenimi v tej študiji. Ključne besede: Capra ibex; mitohondrijska DNA; MHC DRB exon2; ponovna naselitev; upravljanj

Resensies

Book Review 1Book Title: Skollie: One man’s struggle to survive by telling storiesBook Author: John W. FredericksCape Town: Penguin Random House. 251 pp. ISBN: 978-1-77609-199-7.Book Review 2Book Title: A Gap in the HedgeBook Author: Johan Vlok LouwCape Town: Umuzi, 2017. 233 pp. ISBN: 978-1-4152-08915Book Review 3Book Title: Iziganeko zesizwe: Occasional Poems (1900–1943)Book Authors: S.E.K. Mqhayi. Eds. and trans. Jeff Opland and Peter T. MtuzePietermaritzburg: University of KwaZulu Natal Press, 2017. 469 pp. ISBN: 9781869143343; e-ISBN: 9781869143350.Book Review 4Book Title: Oorlog en terpentynBook Authors: Stefan Hertmans. Vertaal deur Daniel HugoPretoria: Protea Boekhuis, 2016. 335 pp. ISBN: 978-1-4853-0610-8; e-Boek: 978-1-4853-0722-8; Epub: 978-1-4853-0723-5.Book Review 5Book Title: Groen soos die hemel daarboBook Author: Eben VenterKaapstad: Tafelberg, 212 pp. ISBN: 978-0-624-08261-3.Book Review 6Book Title: Die wêreld van Charlie OengBook Author: Etienne van HeerdenKaapstad: Tafelberg, 2017. 559 pp. ISBN 978-0-624-08052-7.Book Review 7Book Title: Die diepblou seeBook Author: François LootsKaapstad: Umuzi, 2017. 239 pp. ISBN: 978-1-4152-0953-0.Book Review 8Book Title: Die derde spoelBook Author: S.J. NaudéKaapstad: Umuzi, 2017. 342 pp. ISBN: 978-1-4152-0747-5 (Druk). ISBN: 978-1-4152-0748-2 (ePub).Book Review 9Book Title: Nou, hierBook Author: Corné CoetzeeKaapstad: Human & Rousseau, 2017. 107 pp. ISBN 978-0-7981-7620-0.Book Review 10Book Title: RadbraakBook Author: Jolyn PhillipsKaapstad: Human & Rousseau, 2017. 68 pp. ISBN: 978-0-7981-7616-3.Book Review 11Book Title: VuurvasBook Author: Carel AntonissenNaledi, 2016. ISBN 978-0-928316-97-1.Book Review 12Book Title: Voor ek my kom kryBook Author: Pirow BekkerPretoria: Protea Boekhuis, 2017. 110 pp. ISBN: 978-1-4853-0648-1.Book Review 13Book Title: Nuwe stemme 6Book Authors: Bibi Slippers en Charl-Pierre Naudé (samenstellers)Kaapstad: Tafelberg, 2017. 176 pp. ISBN 9780624082644.Book Review 14Book Title: UittogboekBook Author: Johan MyburgPretoria: Protea, 2017. 100 pp. ISBN: 9781485307761.Book Review 15Book Title: Krap uit die seeBook Author: Fourie BothaPretoria: Protea Boekehuis, 2017. 64 pp. ISBN 9781485307570.Book Review 16Book Title: Skepelinge. Aanloop tot ‘n romanBook Author: Karel SchoemanKaapstad: Human & Rousseau, 2017. 576 pp. ISBN: 978079817610.Book Review 17Book Title: Die reis gaan inwaarts: Die kuns van sterwe in kreatiewe werke van Karel SchoemanBook Author: Cas WepenerStellenbosch: Sun MeDIA MeTRO. Druknaam: SUN PRESS, 2017. 233 pp. ISBN: 978-1-928355-14-4 (Druk); ISBN: 979-1-928355-15-1 (e-boek)

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

Clinical Value of Prognostic Instruments to Identify Patients with an Increased Risk for Osteoporotic Fractures: Systematic Review

There is a plethora of evidence available studying the association of risk profiles and the development of osteoporotic fractures. The small number of out-of-sample validations, the large variety of study characteristics, outcomes and follow-up periods impedes from deriving robust summaries and from conclusions regarding the clinical performance of many tools. First and foremost, future activity in this field should aim at reaching a consensus among clinical experts in respect to the existing instruments. Then we call for careful validations and expedient adaptations for local circumstances of the most promising candidates

Repetitive Pertussis Toxin Promotes Development of Regulatory T Cells and Prevents Central Nervous System Autoimmune Disease

Bacterial and viral infections have long been implicated in pathogenesis and progression of multiple sclerosis (MS). Incidence and severity of its animal model experimental autoimmune encephalomyelitis (EAE) can be enhanced by concomitant administration of pertussis toxin (PTx), the major virulence factor of Bordetella pertussis. Its adjuvant effect at the time of immunization with myelin antigen is attributed to an unspecific activation and facilitated migration of immune cells across the blood brain barrier into the central nervous system (CNS). In order to evaluate whether recurring exposure to bacterial antigen may have a differential effect on development of CNS autoimmunity, we repetitively administered PTx prior to immunization. Mice weekly injected with PTx were largely protected from subsequent EAE induction which was reflected by a decreased proliferation and pro-inflammatory differentiation of myelin-reactive T cells. Splenocytes isolated from EAE-resistant mice predominantly produced IL-10 upon re-stimulation with PTx, while non-specific immune responses were unchanged. Longitudinal analyses revealed that repetitive exposure of mice to PTx gradually elevated serum levels for TGF-β and IL-10 which was associated with an expansion of peripheral CD4+CD25+FoxP3+ regulatory T cells (Treg). Increased frequency of Treg persisted upon immunization and thereafter. Collectively, these data suggest a scenario in which repetitive PTx treatment protects mice from development of CNS autoimmune disease through upregulation of regulatory cytokines and expansion of CD4+CD25+FoxP3+ Treg. Besides its therapeutic implication, this finding suggests that encounter of the immune system with microbial products may not only be part of CNS autoimmune disease pathogenesis but also of its regulation

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements