Effects of rodent poisoning on Powelliphanta traversi

Rat predation is a threat to lowland Powelliphanta traversi (giant predatory land snail), and we have shown that ‘press’ poisoning of rodents (rats and mice) using brodifacoum baits significantly reduces rat abundance relative to non-poisoned areas. The effect on P. t. traversi was evident by the increase in population size, mainly due to adult migration, and a decrease in rat-damaged shells, for areas where rat predation occurs. A longer-term study is required to determine whether prolonged rat control benefits P. t. traversi recruitment. Mouse control was inadequate with use of brodifacoum baits. We document a concomitant rise in bird predation of P. traversi when rat abundance was reduced, suggesting that control of both is necessary to make real conservation gains. However, mortality related to other factors was more common than that caused by predators, possibly due to the habitat drying out periodically. We suggest that low recruitment rates, predator targeting of juveniles (i.e. blackbirds, song thrush and possibly mice and hedgehogs) and poor habitat conditions are the main threats to survival of lowland P. traversi

``Plug and play'' systems for quantum cryptography

We present a time-multiplexed interferometer based on Faraday mirrors, and apply it to quantum key distribution. The interfering pulses follow exactly the same spatial path, ensuring very high stability and self balancing. Use of Faraday mirrors compensates automatically any birefringence effects and polarization dependent losses in the transmitting fiber. First experimental results show a fringe visibility of 0.9984 for a 23km-long interferometer, based on installed telecom fibers.Comment: LaTex, 6 pages, with 2 Postscript figures, Submitted to Applied Physics Letter

A dynamic simulation model for possum and gorse control on a farm woodlot

Managers of farm woodlots in New Zealand are confronted by two major problems: possums and gorse. If these remain uncontrolled then they have a severe impact on the returns from farm woodlots. This paper presents a system dynamics model which has been developed to assist in the analysis of control measures for managing gorse and possums on a farm woodlot in the Makara Valley, Wellington. The model has four main sectors: a tree growth module for radiata pine; a growth module for gorse; a module for the stock of possums present in the habitat; and a module of financial indicators. A number of control experiments are presented which indicate the long term financial and physical consequences of different gorse and possum control measures. The model clearly demonstrates the complex nature of the dynamic behaviour of a system involving biological and environmental factors (ie possums, gorse and trees) and human intervention (in terms of silviculture, and possum and gorse control)

Phenomena exposure from the large scale gas injection test (Lasgit) dataset using a bespoke data analysis toolkit

The Large Scale Gas Injection Test (Lasgit) is a field-scale experiment designed to study the impact of gas buildup and subsequent migration through an engineered barrier system. Lasgit has a substantial experimental dataset containing in excess of 21 million datum points. The dataset is anticipated to contain a wealth of information, ranging from long-term trends and system behaviours to small-scale or ‘second-order’ features. In order to interrogate the Lasgit dataset, a bespoke computational toolkit, designed to expose difficult to observe phenomena, has been developed and applied to the dataset. The preliminary application of the toolkit, presented here, has resulted in a large number of phenomena being indicated/quantified, including highlighting of second-order events (small gas flows, perturbations in stress/pore-water sensors, etc.) and quantification of temperature record frequency content. Localized system behaviour has been shown to occur along with systematic aberrant behaviours that remain unexplained

A novel quantum key distribution scheme with orthogonal product states

The general conditions for the orthogonal product states of the multi-state systems to be used in quantum key distribution (QKD) are proposed, and a novel QKD scheme with orthogonal product states in the 3x3 Hilbert space is presented. We show that this protocol has many distinct features such as great capacity, high efficiency. The generalization to nxn systems is also discussed and a fancy limitation for the eavesdropper's success probability is reached.Comment: 4 Pages, 3 Figure

Precise calculation of parity nonconservation in cesium and test of the standard model

We have calculated the 6s-7s parity nonconserving (PNC) E1 transition amplitude, E_{PNC}, in cesium. We have used an improved all-order technique in the calculation of the correlations and have included all significant contributions to E_{PNC}. Our final value E_{PNC} = 0.904 (1 +/- 0.5 %) \times 10^{-11}iea_{B}(-Q_{W}/N) has half the uncertainty claimed in old calculations used for the interpretation of Cs PNC experiments. The resulting nuclear weak charge Q_{W} for Cs deviates by about 2 standard deviations from the value predicted by the standard model.Comment: 24 pages, 8 figure

Ten years of pulling: Ecosystem recovery after long‐term weed management in Garry oak savanna

Ecosystem restoration is the practice of assisting recovery in degraded ecological communities. The aims of restoration are typically broad, involving the reinstatement of composition, structure, function, and resilience to disturbances. One common restoration tactic in degraded urban systems is to control invasive species, relying on passive restoration for further ecosystem‐level recovery. Here, we test whether this is an effective restoration strategy in Garry oak savanna, a highly threatened and ecologically important community in the North American Pacific Northwest. In urban savanna patches surrounding Victoria, British Columbia, community members have been actively removing aggressive invasive exotic species for over a decade. Based on vegetation surveys from 2007, we tested ecosystem changes in structure, composition, and resilience (i.e., functional redundancy and response diversity) across 10 years of varied management levels. We expected higher levels of invasive species management would correspond with improvements to these ecosystem metrics. However, management explained little of the patterns found over the 10‐year‐period. Woody encroachment was a complicated process of native and exotic invasion, while resilience and compositional changes were most closely tied with landscape connectivity. Thus, though invasive species management may prevent further degradation, active restoration strategies after removal are likely required for recovery of the ecosystem

Measurement of the 6s - 7p transition probabilities in atomic cesium and a revised value for the weak charge Q_W

We have measured the 6s - 7p_{1/2,3/2} transition probabilities in atomic cesium using a direct absorption technique. We use our result plus other previously measured transition rates to derive an accurate value of the vector transition polarizability \beta and, consequently, re-evaluate the weak charge Q_W. Our derived value Q_W=-72.65(49) agrees with the prediction of the standard model to within one standard deviation.Comment: 4 pages, 2 figure

Bambara nut: A review of utlisation, market potential and crop improvement

Bambara groundnut ( Vigna subterranea (L.) Verdc.) originated in West Africa but has become widely distributed throughout the semi-arid zone of sub-Saharan Africa (SSA). Sharing a high nutritive value with other widely consumed legumes, bambara has an appealing flavour which is reflected in demand from small local and niche markets. Despite its high and balanced protein content, bambara remains under-utilised because it takes a long time to cook, contains anti-nutritional factors and does not dehull easily. Bambara yields well under conditions which are too arid for groundnut ( Arachis hypogea ), maize ( Zea mays L.) and even sorghum ( Sorghum bicolar ). Its drought tolerance makes bambara a useful legume to include in climate change adaptation strategies. Existing bambara products are not well promoted in the local or international markets and new products are needed that highlight its inherent nutritional and culinary advantages. A number of projects on bambara, involving several countries in SSA since the 1980s, have failed to stimulate a sustainable increase in the production of the crop. The absence of functioning value chains has been a factor in this failure, as accessible market outlets might provide the required incentive for smallholder households to obtain improved seed and invest more of their land and labour in the crop. There is little documented evidence of trade in bambara but circumstantial evidence indicates considerable international demand. More attention should be given, therefore, to market research and development, with crop improvement programmes being more market-led, if bambara is to make a greater contribution to household income and rural development in SSA.Les arachides Bambara ( Vigna subterranea (L.) Verdc.) d\u2019origine Ouest Africaine ont \ue9t\ue9 largement r\ue9pandues dans la zone semi aride sub saharienne. Avec sa valeur nutritive \ue9lev\ue9e \ue0 c\uf4t\ue9 d\u2019autres l\ue9gumes largement consomm\ue9es, bambara a une saveur attractive qui se refl\ue8te dans sa demande sur des petits march\ue9s locaux. Malgr\ue9 sa teneur \ue9quilibr\ue9e en prot\ue9ines, bambara reste sous utilis\ue9 par suite du long moment de cuisson, contient des facteurs antinutritionnels et sa coque ne s\u2019enl\ue8ve pas facilement. Bambara produit de bons redements dans des conditions qui sont trop arides pour les arachides ( Arachis hypogea ), le ma\ubfs ( Zea mays ) et m\ueame le sorgho ( Sorghum bicolar ). Sa tol\ue9lance en s\ue9cheresse fait du bambara une l\ue9gume utile surtout lorsqu\u2019il s\u2019agit des strat\ue9gies d\u2019adaptation au changement climatique. Les produits existants de bambara ne sont pas bien promus sur des march\ue9s locaux ou internationaux et de nouveaux produits montrant tous les avantages nutritionnels et culinaires sont d\ue9sir\ue9s. Un nombre de projets sur bambara impliquant plusieurs pays d\u2019Afrique Sub Saharienne depuis 1980, ont \ue9chou\ue9 de stimuler une augmentation durable de la production de cette culture. L\u2019absence de cha\ueenes des valeurs fonctionnelles a \ue9t\ue9 un facteur de cet \ue9chec, \ue9tant donn\ue9 que des points de vente sur les march\ue9s accessibles devraient motiver les petits m\ue9nages pour obtenir des semences am\ue9lior\ue9es et plus investir dans leurs terres et la main d\u2019oeuvre. Il ya tr\ue8s peu d\u2019\ue9vidence document\ue9e sur le commerce du bambara mais des \ue9vidences circonstancielles font montrent d\u2019une demande internationale consid\ue9rable. Si bambara doit consid\ue9rablement contribuer \ue0 la g\ue9n\ue9ration des revenus des m\ue9nages et le d\ue9veloppement rural en Afrique Sub Saharienne, un effort doit \ueatre mis dans la recherche et d\ue9veloppement, avec des programmes soutenus d\u2019am\ue9lioration de la culture orient\ue9s vers le march\ue9

Quantum Stabilizer Codes and Classical Linear Codes

We show that within any quantum stabilizer code there lurks a classical binary linear code with similar error-correcting capabilities, thereby demonstrating new connections between quantum codes and classical codes. Using this result -- which applies to degenerate as well as nondegenerate codes -- previously established necessary conditions for classical linear codes can be easily translated into necessary conditions for quantum stabilizer codes. Examples of specific consequences are: for a quantum channel subject to a delta-fraction of errors, the best asymptotic capacity attainable by any stabilizer code cannot exceed H(1/2 + sqrt(2*delta*(1-2*delta))); and, for the depolarizing channel with fidelity parameter delta, the best asymptotic capacity attainable by any stabilizer code cannot exceed 1-H(delta).Comment: 17 pages, ReVTeX, with two figure