New record of the Japanese seahorse Hippocampus mohnikei Bleeker, 1853 (Syngnathiformes: Syngnathidae) in Hong Kong waters

Funding: This study was supported by the Consultancy Project (AFCD/SQ/13/17) of the Agriculture, Fisheries and Conservation Department of the Government of the Hong Kong SAR and the Collaborative Research Fund (C7013-19G) of the Hong Kong Research Grants Council.A new record of Hippocampus mohnikei Bleeker, 1853 was confirmed in Hong Kong through morphological and molecular identification. It is highly possible that there is an established population of H. mohnikei in Hong Kong due to continuous sightings by citizen scientists in the past nine years. The record is significant from a biogeographical perspective as it connects the distributions of known populations in northern China and Japan to those spanning Thailand to India. This further affirms the status of Hong Kong as a hotspot for seahorse biodiversity and conservation in China.Publisher PDFPeer reviewe

SARS-CoV Antibody Prevalence in All Hong Kong Patient Contacts

A total of 1,068 asymptomatic close contacts of patients with severe acute respiratory (SARS) from the 2003 epidemic in Hong Kong were serologically tested, and 2 (0.19%) were positive for SARS coronavirus immunoglobulin G antibody. SARS rarely manifests as a subclinical infection, and at present, wild animal species are the only important natural reservoirs of the virus

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

Cassytha pubescens: germination biology and interactions with native and introduced hosts.

The native hemiparasitic vine Cassytha pubescens infects and often kills the invasive weeds Cytisus scoparius and Ulex europaeus in the Mount Lofty Ranges, South Australia. This leads to the consideration of whether this parasite is a suitable biological control agent for these weeds. The aims of this study were to investigate germination characteristics of the parasite, the direct effects of the parasite on both invasive and native hosts, and the indirect effects of the parasite on interactions between native and invasive hosts. Seed dormancy and germination of C. pubescens were examined. Imbibition tests revealed that the seeds are enclosed in a water impermeable seed coat, which produces physical dormancy. Germination experiments showed that heat and scarification broke the physical dormancy, but the germination rate of heated seeds was over three times higher than that of scarified seeds. Thus this parasite may have evolved to share similar fire-related germination cues as some of its native hosts. The direct impact of C. pubescens on growth of Acacia myrtifolia (a native legume) and Cytisus scoparius (an invasive legume) was investigated in a pot experiment. None of the parasites on infected A. myrtifolia survived, so none of the A. myrtifolia was successfully infected with the parasite. In contrast, C. pubescens successfully infected C. scoparius. Host biomass accumulation was reduced by 21%, relative to uninfected plants. Photosystem II efficiencies were reduced but only on the infected branches. The total nitrogen content of infected plants plus parasite was the same as that of uninfected plants, and there was no impact of infection on nodulation by Rhizobium. Thus, it is likely that the removal of nitrogen by the parasite, reduces the supply to the host, and this limits the biomass accumulation of C. scoparius. The differences in resistance to the parasite by native and invasive hosts were studied. A pot experiment was conducted using [superscript]32P to examine the uptake of nutrients by the parasite from either C. scoparius or A. myrtifolia. In this experiment, C. pubescens was able to successfully attach to A. myrtifolia hosts. The parasite absorbed no [superscript]32P when attached to the native host, but did take up [superscript]32P from the invasive host. This suggests A. myrtifolia resists the formation of functional haustoria by the parasite, while the invasive host does not. It is likely that this resistance of the native host to the native parasite may have evolved through long-term coexistence, whereas the invasive host has had only a short-term association with the parasite. To investigate if the differences in host resistance to C. pubescens lead to changes in competitive outcomes between hosts, plants of the invasive weed Ulex europaeus were grown together with either A. myrtifolia, or a native non-legume, Leptospermum myrsinoides, and either with or without C. pubescens. There was no effect on either biomass accumulation of hosts or on the intensity of competition between hosts. However, as these are perennial species, it is possible that the experiment was too short to detect any effects. Long-term experiments and field monitoring may be required to resolve these competitive interactions. These results provide an important insight into the germination ecology of C. pubescens, and the nature of its impact on both native and invasive hosts. Unlike the morphologically similar holoparasites of the genus Cuscuta, C. pubescens does not seems to act as a carbon sink, thus had little effect on symbiotic nitrogen fixation. This suggests a different carbon-nitrogen economy model form the one proposed for the morphologically similar holoparasites, Cuscuta spp. The study also detected differences in resistance of hosts to the parasite; however, this appeared to have no effect on host competition in a short-term pot experiment.Thesis (M.Sc.) -- University of Adelaide, School of Earth and Environmental Science, 201

New record of the Japanese Seahorse Hippocampus mohnikei Bleeker, 1853 (Syngnathiformes: Syngnathidae) in Hong Kong waters

A new record of Hippocampus mohnikei Bleeker, 1853 was confirmed in Hong Kong through morphological and molecular identification. It is highly possible that there is an established population of H. mohnikei in Hong Kong due to continuous sightings by citizen scientists in the past nine years. The record is significant from a biogeographical perspective as it connects the distributions of known populations in northern China and Japan to those spanning Thailand to India. This further affirms the status of Hong Kong as a hotspot for seahorse biodiversity and conservation in China

New record of the Japanese seahorse <i>Hippocampus mohnikei</i> Bleeker, 1853 (Syngnathiformes: Syngnathidae) in Hong Kong waters

A new record of Hippocampus mohnikei Bleeker, 1853 was confirmed in Hong Kong through morphological and molecular identification. It is highly possible that there is an established population of H. mohnikei in Hong Kong due to continuous sightings by citizen scientists in the past nine years. The record is significant from a biogeographical perspective as it connects the distributions of known populations in northern China and Japan to those spanning Thailand to India. This further affirms the status of Hong Kong as a hotspot for seahorse biodiversity and conservation in China

Measurement of the inclusive jet cross-sections in proton-proton collisions at s=8 \sqrt{s}=8 TeV with the ATLAS detector

International audienceInclusive jet production cross-sections are measured in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=8$ TeV recorded by the ATLAS experiment at the Large Hadron Collider at CERN. The total integrated luminosity of the analysed data set amounts to 20.2 fb$^{−1}$. Double-differential cross-sections are measured for jets defined by the anti-k$_{t}$ jet clustering algorithm with radius parameters of R = 0.4 and R = 0.6 and are presented as a function of the jet transverse momentum, in the range between 70 GeV and 2.5 TeV and in six bins of the absolute jet rapidity, between 0 and 3.0. The measured cross-sections are compared to predictions of quantum chromodynamics, calculated at next-to-leading order in perturbation theory, and corrected for non-perturbative and electroweak effects. The level of agreement with predictions, using a selection of different parton distribution functions for the proton, is quantified. Tensions between the data and the theory predictions are observed