Saltmarsh plants, but not fertilizer, facilitate invertebrate recolonization after an oil spill

Foundation species contribute to the recovery of animal communities from disturbance by engineering, by improving habitat quality, and by regulating food availability. In a salt marsh impacted by the Deepwater Horizon oil spill, we tested the hypothesis that nutrient subsidies would enhance the positive effects of the foundation species Spartina alterniflora on the initial recolonization of benthic invertebrate communities (e.g., copepods, annelids, nematodes) by augmenting food (i.e., microalgae) availability. After two months, plantings of S.alterniflora significantly elevated the densities of the polychaete Capitella capitata, meiofauna-sized annelids, and total macroinfauna over unplanted plots. After 7months, the significant effect of plantings persisted for meiofauna-sized annelids, but not for C.capitata and total macroinfauna. Plantings had no effect on copepods (including Nannopus palustris, the dominant species), nematodes, or microalgal biomass for either month. Nutrient additions did not influence any taxon, despite initial increases in benthic microalgal biomass after 2months. We hypothesize that the structural effects of plants were important to early colonization, possibly by facilitating larval settlement or ameliorating temperature and desiccation stress. Our results emphasize the importance of re-establishing foundation species in oil-impacted sites to enhance recolonization of saltmarsh annelids, but suggest that recolonization is not promoted by the addition of nutrients

Molecular basis of chemosensitivity of platinum pre-treated ovarian cancer to chemotherapy

Ovarian cancer shows considerable heterogeneity in its sensitivity to chemotherapy both clinically and in vitro. This study tested the hypothesis that the molecular basis of this difference lies within the known resistance mechanisms inherent to these patients' tumours

Jejunal Perforation following Screening Colonoscopy

Colonoscopy is rarely associated with complications such as colonic perforation. Perforation of the small bowel is extremely rare, especially if the procedure is done without therapeutic interventions. Several factors are associated with this entity. Perforation of the ileum has been reported, but proximal jejunal perforation secondary to rupture of jejunal diverticulum during colonoscopy has not been reported. We present the case of an 88-year-old patient who developed abdominal pain after undergoing colonoscopy without any additional interventions. Urgent exploration revealed perforation of the proximal jejunum secondary to rupture of a jejunal diverticulum. No therapy or biopsies were undertaken during the colonoscopy, which are known predisposing factors

Universal quantum control of two-electron spin quantum bits using dynamic nuclear polarization

One fundamental requirement for quantum computation is to perform universal manipulations of quantum bits at rates much faster than the qubit's rate of decoherence. Recently, fast gate operations have been demonstrated in logical spin qubits composed of two electron spins where the rapid exchange of the two electrons permits electrically controllable rotations around one axis of the qubit. However, universal control of the qubit requires arbitrary rotations around at least two axes. Here we show that by subjecting each electron spin to a magnetic field of different magnitude we achieve full quantum control of the two-electron logical spin qubit with nanosecond operation times. Using a single device, a magnetic field gradient of several hundred milliTesla is generated and sustained using dynamic nuclear polarization of the underlying Ga and As nuclei. Universal control of the two-electron qubit is then demonstrated using quantum state tomography. The presented technique provides the basis for single and potentially multiple qubit operations with gate times that approach the threshold required for quantum error correction.Comment: 11 pages, 4 figures. Supplementary Material included as ancillary fil

Nigerian foodstuffs with prostate cancer chemopreventive polyphenols

Dietary polyphenols are antioxidants that can scavenge biological free radicals, and chemoprevent diseases with biological oxidation as their main etiological factor. In this paper, we review our laboratory data vis-ὰ-vis available literature on prostate cancer chemopreventive substances in Nigerian foodstuffs. Dacryodes edulis fruit, Moringa oleifera and Syzygium aromaticum contained prostate active polyphenols like ellagic acid, gallate, methylgallate, catechol, kaempferol quercetin and their derivatives. Also Canarium schweinfurthii Engl oil contained ten phenolic compounds and lignans, namely; catechol, p-hydroxybenzaldehyde, dihydroxyphenylacetic acid, tyrosol, p-hydroxybenzoic acid, dihydroxybenzoic acid, vanillic acid, phloretic acid, pinoresinol, secoisolariciresinol. In addition, tomatoes (Lycopersicon esculentum Mill) which contains the powerful antioxidant and anti-prostate cancer agent, lycopene; cabbage (Brassica oleracea) containing indole-3-carbinol; citrus fruits containing pectin; Soursop (Annona muricata) containing annonaceous acetogenins; soya beans (Glycine max) containing isoflavones; chilli pepper (Capsicum annuum) containing capsaicin, and green tea (Camellia sinensis) containing (-) epigallocatechin gallate (EGCG), (-) epicatechin, (-) epicatechin-3-gallate and (-) epigallocatechin -3-gallate which are widely reported to posses prostate cancer chemopreventive compounds are also grown in Nigeria and other African countries. Thus, the high incidence of prostate cancer among males of African extraction can be dramatically reduced, and the age of onset drastically increased, if the population at risk consumes the right kinds of foods in the right proportion, beginning early in life, especially as prostate cancer has a latency period of about 50 years

Triplet-Singlet Spin Relaxation via Nuclei in a Double Quantum Dot

The spin of a confined electron, when oriented originally in some direction, will lose memory of that orientation after some time. Physical mechanisms leading to this relaxation of spin memory typically involve either coupling of the electron spin to its orbital motion or to nuclear spins. Relaxation of confined electron spin has been previously measured only for Zeeman or exchange split spin states, where spin-orbit effects dominate relaxation, while spin flips due to nuclei have been observed in optical spectroscopy studies. Using an isolated GaAs double quantum dot defined by electrostatic gates and direct time domain measurements, we investigate in detail spin relaxation for arbitrary splitting of spin states. Results demonstrate that electron spin flips are dominated by nuclear interactions and are slowed by several orders of magnitude when a magnetic field of a few millitesla is applied. These results have significant implications for spin-based information processing

Bayesian paternity analysis and mating patterns in a parasitic nematode, Trichostrongylus tenuis

Mating behaviour is a fundamental aspect of the evolutionary ecology of sexually reproducing species, but one that has been under-researched in parasitic nematodes. We analysed mating behaviour in the parasitic nematode Trichostrongylus tenuis by performing a paternity analysis in a population from a single red grouse host. Paternity of the 150 larval offspring of 25 mothers (sampled from one of the two host caeca) was assigned among 294 candidate fathers (sampled from both caeca). Each candidate father's probability of paternity of each offspring was estimated from 10-locus microsatellite genotypes. Seventy-six (51%) offspring were assigned a father with a probability of >0.8, and the estimated number of unsampled males was 136 (95% credible interval (CI) 77-219). The probability of a male from one caecum fathering an offspring in the other caecum was estimated as 0.024 (95% CI 0.003-0.077), indicating that the junction of the caeca is a strong barrier to dispersal. Levels of promiscuity (defined as the probability of two of an adult's offspring sharing only one parent) were high for both sexes. Variance in male reproductive success was moderately high, possibly because of a combination of random mating and high variance in post-copulatory reproductive success. These results provide the first data on individual mating behaviour among parasitic nematodes

Multiwavelength monitoring and X-ray brightening of Be X-ray binary PSR J2032+4127/MT91 213 on its approach to periastron

The radio and gamma-ray pulsar PSR J2032+4127 was recently found to be in a decades-long orbit with the Be star MT91 213, with the pulsar moving rapidly towards periastron. This binary shares many similar characteristics with the previously unique binary system PSR B1259−63/LS 2883. Here, we describe radio, X-ray, and optical monitoring of PSR J2032+4127/MT91 213. Our extended orbital phase coverage in radio, supplemented with Fermi LAT gamma-ray data, allows us to update and refine the orbital period to 45–50 yr and time of periastron passage to 2017 November. We analyse archival and recent Chandra and Swift observations and show that PSR J2032+4127/MT91 213 is now brighter in X-rays by a factor of ∼70 since 2002 and ∼20 since 2010. While the pulsar is still far from periastron, this increase in X-rays is possibly due to collisions between pulsar and Be star winds. Optical observations of the Hα emission line of the Be star suggest that the size of its circumstellar disc may be varying by ∼2 over time-scales as short as 1–2 months. Multiwavelength monitoring of PSR J2032+4127/MT91 213 will continue through periastron passage, and the system should present an interesting test case and comparison to PSR B1259−63/LS 2883

Alpha-invariants and purely log terminal blow-ups

We prove that the sum of the $\alpha$-invariants of two different Koll\'ar components of a Kawamata log terminal singularity is less than $1$.Comment: 12 page

CMB Telescopes and Optical Systems

The cosmic microwave background radiation (CMB) is now firmly established as a fundamental and essential probe of the geometry, constituents, and birth of the Universe. The CMB is a potent observable because it can be measured with precision and accuracy. Just as importantly, theoretical models of the Universe can predict the characteristics of the CMB to high accuracy, and those predictions can be directly compared to observations. There are multiple aspects associated with making a precise measurement. In this review, we focus on optical components for the instrumentation used to measure the CMB polarization and temperature anisotropy. We begin with an overview of general considerations for CMB observations and discuss common concepts used in the community. We next consider a variety of alternatives available for a designer of a CMB telescope. Our discussion is guided by the ground and balloon-based instruments that have been implemented over the years. In the same vein, we compare the arc-minute resolution Atacama Cosmology Telescope (ACT) and the South Pole Telescope (SPT). CMB interferometers are presented briefly. We conclude with a comparison of the four CMB satellites, Relikt, COBE, WMAP, and Planck, to demonstrate a remarkable evolution in design, sensitivity, resolution, and complexity over the past thirty years.Comment: To appear in: Planets, Stars and Stellar Systems (PSSS), Volume 1: Telescopes and Instrumentatio