Organic and conventional tomato cropping systems.

Among several alternative agricultural systems have been developed, organic agriculture has deserved increasing interest from. The objective of this paper was comparing both organic (OS) and conventional (CS) tomato cropping systems for varieties Débora and Santa Clara, through an interdisciplinary study. The experiment was set up in a randomized blocks design with six replicates, in a dystrophic Ultisol plots measuring 25 ´ 17 m. Cropping procedures followed by either local conventional or organic growers practices recommendations. Fertilization in the OS was done with organic compost, single superphosphate, dolomitic limes (5L, 60 g, and 60 g per pit), and sprayed twice a week with biofertilizer. Fertilization in the CS was done with 200 g 4-14-8 (NPK) per pit and, after planting, 30 g N, 33 g K and 10.5 g P per pit; from 52 days after planting forth, plants were sprayed once a week with foliar fertilizer. In the CS, a blend of insecticides, fungicides and miticides was sprayed twice a week, after planting. In the OS, extracts of black pepper, garlic, and Eucalyptus; Bordeaux mixture, and biofertilizer, were applied twice a week to control diseases and pests. Tomato spotted wilt was the most important disease in the OS, resulting in smaller plant development, number of flower clusters and yield. In the CS, the disease was kept under control, and the population of thrips, the virus vector, occurred at lower levels than in the OS. Variety Santa Clara presented greater incidence of the viral disease, and for this reason had a poorer performance than 'Débora', especially in the OS. Occurrence of Liriomyza spp. was significantly smaller in the OS, possibly because of the greater frequency of Chrysoperla. The CS had smaller incidence of leaf spots caused by Septoria lycopersici and Xanthomonas vesicatoria. However, early blight and fruit rot caused by Alternaria solani occurred in larger numbers. No differences were observed with regard to the communities of fungi and bacteria in the phylloplane, and to the occurrence of weeds

Psychological health of Australian veterans of the 1991 Gulf War: an assessment using the SF-12, GHQ-12 and PCL-S

Background. Elevated rates of psychological morbidity and symptomatology have been widely reported in 1991 Gulf War veterans. The present study used brief self-report instruments to compare the psychological health of Australian Gulf War veterans with that of a randomly sampled military comparison group. Method. The 12-item Short Form Health Survey (SF-12), 12-item General Health Questionnaire (GHQ-12), Posttraumatic Stress Disorder Checklist – Specific (PCL-S) and Military Service Experience (MSE) questionnaire were administered to 1424 male Australian Gulf War veterans and 1548 male Australian Defence Force members who were operational at the time of the Gulf War conflict, but were not deployed there. Results. The Gulf War veterans exhibited poorer psychological health, as measured by the above three instruments, than the comparison group members. For Gulf War veterans, the number of stressful experiences, as measured by the MSE questionnaire, was correlated with scores on the three instruments. SF-12 mental health component summary scores and PCL-S caseness, but not GHQ-12 caseness, differed significantly between Gulf War veterans and comparison group members who had been on at least one active deployment. Conclusions. More than a decade after the 1991 Gulf War, Australian Gulf War veterans are exhibiting higher levels of current (past month) psychological ill-health, as measured using the GHQ-12 and PCL-S, as well as lower mental health status, as measured by the SF-12, than the comparison group. Although not a replacement for formal psychiatric diagnosis, instruments such as those above may aid in the assessment of veterans' psychological health.D. P. McKenzie, J. F. Ikin, A. C. McFarlane, M. Creamer, A. B. Forbes, H. L. Kelsall, D. C. Glass, P. Ittak and M. R. Si

Compact phases of polymers with hydrogen bonding

We propose an off-lattice model for a self-avoiding homopolymer chain with two different competing attractive interactions, mimicking the hydrophobic effect and the hydrogen bond formation respectively. By means of Monte Carlo simulations, we are able to trace out the complete phase diagram for different values of the relative strength of the two competing interactions. For strong enough hydrogen bonding, the ground state is a helical conformation, whereas with decreasing hydrogen bonding strength, helices get eventually destabilized at low temperature in favor of more compact conformations resembling $\beta$-sheets appearing in native structures of proteins. For weaker hydrogen bonding helices are not thermodynamically relevant anymore.Comment: 5 pages, 3 figures; revised version published in PR

Behavioural and electrophysiological characterisation of experimentally induced osteoarthritis and neuropathy in C57Bl/6 mice

Background: Osteoarthritis is a widespread condition affecting the elderly where similar to 70-90% of over 75 year olds are affected, representing one of the largest cost burdens to healthcare in the western world. The monosodium iodoacetate (MIA) osteoarthritis model has been well described in the rat especially in terms of the pathological progression of the disease and more recently pain behaviour. In this study, we characterise, for the first time, MIA induced osteoarthritis in mice and compare it with nerve-injured mice (partial sciatic nerve injury), using both behavioural and in vivo electrophysiological measurements. These approaches uniquely allow the threshold and suprathreshold measures to many modalities to be quantified and so form a basis for improving and expanding transgenic studies.Results: Significant mechanical hypersensitivity was observed in the ipsilateral hindpaw in MIA injected mice at all observed time points following infrapetellar MIA injection (p < 0.05). The mechanical hypersensitivity exhibited a partial biphasic temporal pattern, but thermal hypersensitivity was absent. Electrically-evoked dorsal horn neuronal responses in MIA injected mice were significantly elevated (p < 0.05) with respect to A- and C-fibre firing, input, pinch and noxious von Frey (26 and 60 g). No significant changes in A- or C-fibre thresholds were observed. Nerve-injured mice displayed significant behavioural thermal and mechanical hypersensitivity (p < 0.05) and evoked dorsal horn responses were significantly increased with respect to C-fibre firing, pinch and wind-up (p < 0.05).Conclusion: The MIA model of osteoarthritic pain in mice displays behavioural characteristics similar to those observed in rats. Changes in both behavioural measures and neuronal activity from the paw, suggest that central changes are involved in this pain state, although a role for peripheral drives is also likely. Moreover, the behavioural and neuronal measures in these two pain models showed overlapping alterations in terms of certain neuronal measures and mechanical sensitivity despite their very different pathologies and a loss of input in neuropathy, suggesting some commonalities in the central processing of different peripheral pain states. This murine model of osteoarthritis will allow the exploitation of knock out animals to better understand underlying mechanisms and identify novel molecular targets

Graphical representation of the partition function for a 1-D delta-function Bose gas

One-dimensional repulsive delta-function bose system is studied. By only using the Bethe ansatz equation, n-particle partition functions are exactly calculated. From this expression for the n-particle partition function, the n-particle cluster integral is derived. The results completely agree with those of the thermal Bethe ansatz (TBA). This directly proves the validity of the TBA. The theory of partitions and graphs is used to simplify the discussion.Comment: 15 page

Technical report: Modeling nitrate leaching risk from specialty crop fields during on-farm managed floodwater recharge in the Kings Groundwater Basin and the potential for its management

This project has focused on better understanding the potential impact of On-Farm Flood Capture and Recharge (OFFCR) on groundwater quality pertaining to salts and nitrate and on assessing potential management opportunities. To achieve these goals, we used a combination of field and modeling studies. For the field study, soil cores were taken to a depth of 30 feet in replicate across fields with three different specialty crops identified as important to the San Joaquin Valley (tomatoes, almonds, vineyards) and with potential suitability for OFFCR. A prime goal of the field study was to provide data for parameterizing two models developed to assess nitrate, salt and water transport through the vadose zone, prior to percolating into the groundwater aquifer. However, the field study also resulted in key findings that show its value as a stand-alone study: 1) Nitrate concentrations are highest in the upper vadose zone and affected by texture. Those effects are not evident in the deeper vadose zone. 2) Vadose zone nitrate concentrations are affected by the crop grown. These results suggest an opportunity for lower legacy mass transport for grapes and higher legacy mass transport for both tomatoes and almonds. 3) Variability in individual farmers’ past and present fertilizer and water management practices contributes to different legacy salt and nitrate loads in the vadose zone. Data from the field study and other related and concurrent OFFCR field efforts were used during model development. The overall modeling approach was designed to model nitrate and salt transport for lands under OFFCR operation for different crop types, vadose zone characteristics and groundwater characteristics. The defined goals of this design and modeling approach were to: 1) model nitrate and salt movement through the vadose zone and into groundwater; 2) test the model against scenarios that consider different recharge rates, cultural practices, soil types, and depths to groundwater, assessing the timing and magnitude of loading through the vadose zone and the effects on underlying groundwater; and 3) recommend management practices to mitigate potential groundwater impacts. To achieve these goals, two models were integrated to simulate nitrate and salt transport through the vadose zone to groundwater under different scenarios: a 1D Hydrus model and an analytical groundwater model (AGM)

Local correlations in a strongly interacting 1D Bose gas

We develop an analytical method for calculating local correlations in strongly interacting 1D Bose gases, based on the exactly solvable Lieb-Liniger model. The results are obtained at zero and finite temperatures. They describe the interaction-induced reduction of local many-body correlation functions and can be used for achieving and identifying the strong-coupling Tonks-Girardeau regime in experiments with cold Bose gases in the 1D regime.Comment: 8 pages, REVTeX4, published in the New Journal of Physic