Integrated Silicon Photonics for High-Speed Quantum Key Distribution

Integrated photonics offers great potential for quantum communication devices in terms of complexity, robustness and scalability. Silicon photonics in particular is a leading platform for quantum photonic technologies, with further benefits of miniaturisation, cost-effective device manufacture and compatibility with CMOS microelectronics. However, effective techniques for high-speed modulation of quantum states in standard silicon photonic platforms have been limited. Here we overcome this limitation and demonstrate high-speed low-error quantum key distribution modulation with silicon photonic devices combining slow thermo-optic DC biases and fast (10~GHz bandwidth) carrier-depletion modulation. The ability to scale up these integrated circuits and incorporate microelectronics opens the way to new and advanced integrated quantum communication technologies and larger adoption of quantum-secured communications

A Situation Analysis of Ley Pasture Utilisation in the Western Downs and Maranoa Regions of S Queensland, Australia

Previous studies have shown that the uptake of ley pasture systems in S Queensland\u27s grain growing region has been slow when compared with mixed farming systems in S Australia. This is despite their demonstrated benefits to subsequent crops, livestock production and the environment. A survey was conducted that aimed to determine the level of utilisation of ley pastures in the Western Downs and Maranoa regions of S Queensland, and the possible constraints to their adoption, and benefits arising from their use. The survey also aimed to determine the commonly used pasture species, the reasons for their use and their contribution to the livestock component of mixed farms

A Situation Analysis of Ley Pasture Utilisation in the Western Downs and Maranoa Regions of S Queensland, Australia

Previous studies have shown that the uptake of ley pasture systems in S Queensland\u27s grain growing region has been slow when compared with mixed farming systems in S Australia. This is despite their demonstrated benefits to subsequent crops, livestock production and the environment. A survey was conducted that aimed to determine the level of utilisation of ley pastures in the Western Downs and Maranoa regions of S Queensland, and the possible constraints to their adoption, and benefits arising from their use. The survey also aimed to determine the commonly used pasture species, the reasons for their use and their contribution to the livestock component of mixed farms

The REFANI-N study protocol: a cluster-randomised controlled trial of the effectiveness and cost-effectiveness of early initiation and longer duration of emergency/seasonal unconditional cash transfers for the prevention of acute malnutrition among children, 6-59 months, in Tahoua, Niger.

BACKGROUND: The global burden of acute malnutrition among children remains high, and prevalence rates are highest in humanitarian contexts such as Niger. Unconditional cash transfers are increasingly used to prevent acute malnutrition in emergencies but lack a strong evidence base. In Niger, non-governmental organisations give unconditional cash transfers to the poorest households from June to September; the 'hunger gap'. However, rising admissions to feeding programmes from March/April suggest the intervention may be late. METHODS/DESIGN: This cluster-randomised controlled trial will compare two types of unconditional cash transfer for 'very poor' households in 'vulnerable' villages defined and identified by the implementing organisation. 3,500 children (6-59 months) and 2,500 women (15-49 years) will be recruited exhaustively from households targeted for cash and from a random sample of non-recipient households in 40 villages in Tahoua district. Clusters of villages with a common cash distribution point will be assigned to either a control group which will receive the standard intervention (n = 10), or a modified intervention group (n = 10). The standard intervention is 32,500 FCFA/month for 4 months, June to September, given cash-in-hand to female representatives of 'very poor' households. The modified intervention is 21,500 FCFA/month for 5 months, April, May, July, August, September, and 22,500 FCFA in June, providing the same total amount. In both arms the recipient women attend an education session, women and children are screened and referred for acute malnutrition treatment, and the households receive nutrition supplements for children 6-23 months and pregnant and lactating women. The trial will evaluate whether the modified unconditional cash transfer leads to a reduction in acute malnutrition among children 6-59 months old compared to the standard intervention. The sample size provides power to detect a 5 percentage point difference in prevalence of acute malnutrition between trial arms. Quantitative and qualitative process evaluation data will be prospectively collected and programme costs will be collected and cost-effectiveness ratios calculated. DISCUSSION: This randomised study design with a concurrent process evaluation will provide evidence on the effectiveness and cost-effectiveness of earlier initiation of seasonal unconditional cash transfer for the prevention of acute malnutrition, which will be generalisable to similar humanitarian situations. TRIAL REGISTRATION: ISRCTN25360839 , registered March 19, 2015

Cretaceous age, composition, and microstructure of pseudotachylyte in the Otago Schist, New Zealand

At Tucker Hill, in Central Otago, New Zealand, a series of pseudotachylyte veins are hosted in quartzofeldspathic schist. Chilled margins, microlites, flow banding, and the crystallisation of mineral phases absent from the host rock provide unequivocal evidence for melting during pseudotachylyte formation. Whole rock analyses of pseudotachylyte reveal c. 3 enrichment of K2O, Ba, and Rb, and similar depletion of Na2O, CaO, Sr, and Eu, as compared to host schist. Formation age of pseudotachylyte is 95.9±1.8 Ma as measured by total fusion 40Ar/39Ar analyses. Stepwise heating of pseudotachylyte matrix yields an excellently defined 40Ar/39Ar plateau age of 96.0±0.3 Ma. These well-defined ages are attributed to the presence of potassium feldspar, low abundance of inherited lithic material from the host rock, and few fluid inclusions containing extraneous Ar. We propose that formation of these pseudotachylyte veins was related to Cretaceous extensional uplift and exhumation of the Otago Schist

Flip Graphs of Degree-Bounded (Pseudo-)Triangulations

We study flip graphs of triangulations whose maximum vertex degree is bounded by a constant $k$. In particular, we consider triangulations of sets of $n$ points in convex position in the plane and prove that their flip graph is connected if and only if $k > 6$; the diameter of the flip graph is $O(n^2)$. We also show that, for general point sets, flip graphs of pointed pseudo-triangulations can be disconnected for $k \leq 9$, and flip graphs of triangulations can be disconnected for any $k$. Additionally, we consider a relaxed version of the original problem. We allow the violation of the degree bound $k$ by a small constant. Any two triangulations with maximum degree at most $k$ of a convex point set are connected in the flip graph by a path of length $O(n \log n)$, where every intermediate triangulation has maximum degree at most $k+4$.Comment: 13 pages, 12 figures, acknowledgments update

A critical role for astrocytes in hypercapnic vasodilation in brain

Cerebral blood flow (CBF) is controlled by arterial blood pressure, arterial CO2, arterial O2, and brain activity and is largely constant in the awake state. Although small changes in arterial CO2 are particularly potent to change CBF (1 mmHg variation in arterial CO2 changes CBF by 3-4%), the coupling mechanism is incompletely understood. We tested the hypothesis that astrocytic prostaglandin E2 (PgE2) plays a key role for cerebrovascular CO2 reactivity and that preserved synthesis of glutathione is essential for the full development of this response. We combined two-photon imaging microscopy in brain slices with in vivo work in rats and C57Bl/6J mice to examine the hemodynamic responses to CO2 and somatosensory stimulation before and after inhibition of astrocytic glutathione and PgE2 synthesis. We demonstrate that hypercapnia (increased CO2) evokes an increase in astrocyte [Ca2+]i and stimulates COX-1 activity. The enzyme downstream of COX-1 that synthesizes PgE2 (microsomal prostaglandin E synthase-1) depends critically for its vasodilator activity on the level of glutathione in the brain. We show that when glutathione levels are reduced, astrocyte calcium-evoked release of PgE2 is decreased and vasodilation triggered by astrocyte [Ca2+]i in vitro and by hypercapnia in vivo is inhibited. Astrocyte synthetic pathways, dependent on glutathione, are involved in cerebrovascular reactivity to CO2. Reductions in glutathione levels in ageing, stroke or schizophrenia could lead to dysfunctional regulation of CBF and subsequent neuronal damage

Structural Controls on Crustal Fluid Circulation and Hot Spring Geochemistry Above a Flat‐Slab Subduction Zone, Peru

Hot spring geochemistry from the Cordillera Blanca and Cordillera Huayhuash, Peru, reveal the influence of crustal‐scale structures on geothermal fluid circulation in an amagmatic region located above a flat‐slab subduction zone. To test the influence of contrasting modes of faulting in these regions, springs were targeted along the Cordillera Blanca detachment fault, within its hanging wall, in the footwall of the detachment, and in the Cordillera Huayhuash. Hot springs along the Cordillera Blanca detachment fault zone are associated with recent extension and normal faulting, and those in its footwall and the Cordillera Huayhuash are located in the Marañon fold and thrust belt where compressional structures dominate. Springs along and in the hanging wall of the Cordillera Blanca detachment fault yield brackish‐saline, alkaline‐chloride waters, with oxygen, hydrogen, carbon, and chlorine stable isotope values that suggest mixing between meteoric groundwater and saline brine affected by high water‐rock interaction. Geothermometry reservoir temperature estimates (RTEs) of 91–226°C indicate maximum flow path depths of 8.7 or 11 km, depending on geothermal gradient, associated with the Cordillera Blanca detachment fault. In contrast, springs in the footwall and in the Cordillera Huayhuash exhibit a wide range of water types with an isotopic affinity to meteoric water, suggesting a greater influence from shallow groundwater and less water‐rock interaction. For these springs, RTEs of 40–98°C correspond to much shallower circulation (1.6–4 km). Results indicate that the Cordillera Blanca detachment system accommodates significantly deeper circulation of crustal fluids compared to other regional compressional structures