Precision Drought Stress in Orchards: Rootstock Evaluation, Trunk Hydration and Canopy Temperature

In many areas, over half of all diverted water is used for irrigation. Tree fruit crops use a lot of water, but water productivity can be increased using properly-timed precision water stress. In addition to water conservation, increases in water productivity arise from better fruit quality, increased storage life and reductions in pruning and maintenance. One major hurdle to applying precision water stress in orchards is the lack of a reliable, automated method of determining tree water status. However, the influence of physiological characteristics such as rootstock vigor on water productivity are also important. Selecting the most appropriate rootstocks and accurately determining the water status of orchard trees can increase water productivity. Research has shown that some rootstocks can more effectively extract water from soil. In this research, the response to water stress of three different Gisela tart cherry dwarfing rootstocks was compared using a weighing lysimeter system. Gisela 12 and Gisela 3 rootstocks recovered from drought stress more quickly and had higher trunk diameter growth rates than drought-stressed Gisela 5 rootstocks. Two potential methods of determining tree water status were also evaluated. Trunk hydration was measured using electromagnetic sensors and canopy temperature changes were detected using infrared radiometry. Electromagnetic techniques, including time domain reflectometry, can be used to determine the water content of wood. Until recently, the cost of this technology has inhibited its widespread use, but new affordable commercial electromagnetic soil moisture sensors have created renewed interest in this technique. In this research five different types of electromagnetic soil moisture sensors were inserted into the trunks of fruit trees and were monitored over two growing seasons. Maximizing exposure of waveguides to the sapwood increased the response of these sensors to changes in stem water potential. Infrared measurements of canopy temperature have successfully been used with field crops. However, the heterogeneity of orchard canopies makes this technique more difficult in orchards. Here, the efficacy of aiming radiometers at single trees versus at entire orchards was compared over multiple growing seasons. Neither single tree measurements nor whole orchard techniques produced a sufficiently robust signal to recommend them for general use

Kv7 Channel Activation Underpins EPAC-Dependent Relaxations of Rat Arteries.

OBJECTIVE: To establish the role of Kv7 channels in EPAC (exchange protein directly activated by cAMP)-dependent relaxations of the rat vasculature and to investigate whether this contributes to β-adrenoceptor-mediated vasorelaxations. APPROACH AND RESULTS: Isolated rat renal and mesenteric arteries (RA and MA, respectively) were used for isometric tension recording to study the relaxant effects of a specific EPAC activator and the β-adrenoceptor agonist isoproterenol in the presence of potassium channel inhibitors and cell signaling modulators. Isolated myocytes were used in proximity ligation assay studies to detect localization of signaling intermediaries with Kv7.4 before and after cell stimulation. Our studies showed that the EPAC activator (8-pCPT-2Me-cAMP-AM) produced relaxations and enhanced currents of MA and RA that were sensitive to linopirdine (Kv7 inhibitor). Linopirdine also inhibited isoproterenol-mediated relaxations in both RA and MA. In the MA, isoproterenol relaxations were sensitive to EPAC inhibition, but not protein kinase A inhibition. In contrast, isoproterenol relaxations in RA were attenuated by protein kinase A but not by EPAC inhibition. Proximity ligation assay showed a localization of Kv7.4 with A-kinase anchoring protein in both vessels in the basal state, which increased only in the RA with isoproterenol stimulation. In the MA, but not the RA, a localization of Kv7.4 with both Rap1a and Rap2 (downstream of EPAC) increased with isoproterenol stimulation. CONCLUSIONS: EPAC-dependent vasorelaxations occur in part via activation of Kv7 channels. This contributes to the isoproterenol-mediated relaxation in mesenteric, but not renal, arteries

Quantifying Tree Hydration Using Electromagnetic Sensors

An automated method of determining tree water status would enable tree fruit growers, foresters and arborists to reduce water consumption, reduce orchard maintenance costs and improve fruit quality. Automated measurements could also be used to irrigate based on need rather than on fixed schedules. Numerous automated approaches have been studied; all are difficult to implement. Electromagnetic sensors that measure volumetric water content can be inserted in tree trunks to determine relative changes in tree water status. We performed automated measurements of dielectric permittivity using four commercially available electromagnetic sensors in fruit tree trunks over the 2016 growing season. These sensors accurately measure the ratio of air and water in soils, but tree trunks have minimal air-filled porosity. The sensors do respond, however, to bound and unbound water and the relative change in the output of the sensors thus provides an indication of this ratio. Sapwood is the hydro-dynamically responsive component of trunk anatomy and is nearest the bark. Sensor response improved when the waveguides were exposed to a greater percentage of sapwood. Irrigation-induced increases of approximately 0.5 MPa in stem water potential were associated with 0.5 unit increases in dielectric permittivity. Electromagnetic sensors respond to bound water in trees and thus have the potential to indicate tree water status, especially when the sensor rods are in contact with sapwood. Sensor modifications and/or innovative installation techniques could enable automated measurements of tree water status that could be used to precision irrigate trees

SMIT (Sodium-Myo-Inositol Transporter) 1 Regulates Arterial Contractility Through the Modulation of Vascular Kv7 Channels

Objective: The SMIT1 (sodium:myo-inositol transporter 1) regulates myo-inositol movement into cells and responses to hypertonic stimuli. Alteration of myo-inositol levels has been associated with several diseases, including hypertension, but there is no evidence of a functional role of SMIT1 in the vasculature. Recent evidence showed that in the nervous system SMIT1 interacted and modulated the function of members of the Kv7 family of voltage-gated potassium channels, which are also expressed in the vasculature where they regulate arterial contractility. Therefore, in this study, we evaluated whether SMIT1 was functionally relevant in arterial smooth muscle. Approach and Results: Immunofluorescence and polymerase chain reaction experiments revealed that SMIT1 was expressed in rat renal and mesenteric vascular smooth muscle cells. Isometric tension recordings showed that incubation of renal arteries with raffinose and myo-inositol (which increases SMIT1 expression) reduced the contractile responses to methoxamine, an effect that was abolished by preincubation with the pan-Kv7 blocker linopirdine and by molecular knockdown of Kv7.4 and Kv7.5. Knockdown of SMIT1 increased the contraction of renal arteries induced by methoxamine, impaired the response to the Kv7.2–Kv7.5 activator ML213 but did not interfere with the relaxant responses induced by openers of other potassium channels. Proximity ligation assay showed that SMIT1 interacted with heteromeric channels formed by Kv7.4 and Kv7.5 channels in both renal and mesenteric vascular smooth muscle cells. Patch-clamp experiments showed that incubation with raffinose plus myo-inositol increased Kv7 currents in vascular smooth muscle cells. Conclusions: SMIT1 protein is expressed in vascular smooth muscle cells where it modulates arterial contractility through an association with Kv7.4/Kv7.5 heteromers

Effect of statins on atrial fibrillation: collaborative meta-analysis of published and unpublished evidence from randomised controlled trials

Objective To examine whether statins can reduce the risk of atrial fibrillation. Design Meta-analysis of published and unpublished results from larger scale statin trials, with comparison of the findings against the published results from smaller scale or shorter duration studies. Data sources Medline, Embase, and Cochrane's CENTRAL up to October 2010. Unpublished data from longer term trials were obtained through contact with investigators. Study selection Randomised controlled trials comparing statin with no statin or comparing high dose versus standard dose statin; all longer term trials had at least 100 participants and at least six months' follow-up. Results In published data from 13 short term trials (4414 randomised patients, 659 events), statin treatment seemed to reduce the odds of an episode of atrial fibrillation by 39% (odds ratio 0.61, 95% confidence interval 0.51 to 0.74; P<0.001), but there was significant heterogeneity (P<0.001) between the trials. In contrast, among 22 longer term and mostly larger trials of statin versus control (105 791 randomised patients, 2535 events), statin treatment was not associated with a significant reduction in atrial fibrillation (0.95, 0.88 to 1.03; P=0.24) (P<0.001 for test of difference between the two sets of trials). Seven longer term trials of more intensive versus standard statin regimens (28 964 randomised patients and 1419 events) also showed no evidence of a reduction in the risk of atrial fibrillation (1.00, 0.90 to 1.12; P=0.99). Conclusions The suggested beneficial effect of statins on atrial fibrillation from published shorter term studies is not supported by a comprehensive review of published and unpublished evidence from larger scale trials

Structural and dynamical properties of liquid Si. An orbital-free molecular dynamics study

Several static and dynamic properties of liquid silicon near melting have been determined from an orbital free {\em ab-initio} molecular dynamics simulation. The calculated static structure is in good agreement with the available X-ray and neutron diffraction data. The dynamical structure shows collective density excitations with an associated dispersion relation which closely follows recent experimental data. It is found that liquid silicon can not sustain the propagation of shear waves which can be related to the power spectrum of the velocity autocorrelation function. Accurate estimates have also been obtained for several transport coefficients. The overall picture is that the dynamic properties have many characteristics of the simple liquid metals although some conspicuous differences have been found.Comment: 12 pages, 11 figure

Exploring experiences and needs of spousal carers of people with behavioural variant frontotemporal dementia (bvFTD) including those with familial FTD (fFTD): a qualitative study

INTRODUCTION: Carers of people with frontotemporal dementia (FTD) experience greater challenges than carers of people with other dementias due to the younger age of onset and the challenging presentation of symptoms. The aim of the present study was to explore experiences of spousal carers of people with bvFTD, including those with the familial form of the disease (fFTD). METHOD: Fourteen qualitative interviews were analysed using an inductive approach to Thematic Analysis to understand experiences of spousal carers of people with bvFTD including those with fFTD. RESULTS: Five main themes were identified including: a) The "Constant Battle" - A journey toward an FTD diagnosis, b) Shock, Relief and Fear - Challenges persist post diagnosis, c) The "Life Altering" impact - The loss of the spousal relationship and shifting roles, d) Adapting, Managing Symptoms and Receiving Carer Support, e) Lack of General Knowledge - Barriers to support. CONCLUSIONS: Healthcare professionals should be educated on the initial presentations of FTD, to enable carers and families receive timely diagnosis and appropriate support. Future research should investigate the impact of fFTD on carers and families, to explore positive or meaningful experiences in caring, as well as theory-driven research to identify helpful coping strategies for carers of people with FTD

The importance of cephalopods in the diet of fish on the northwest European shelf.

Cephalopods are universal to the world's oceans and prey to many fish species. On the northwest European shelf, integrated ecosystem assessments are rapidly evolving into the preferred method for holistically assessing stocks, but cephalopods appear to be an overlooked component, perhaps because their roles in ecosystems have seldom been quantified in recent years. We have analysed historical fish stomach records and revisited literature at local and regional level to determine the importance of cephalopods to the diets of 26 ecologically important finfish. We conclude that, in contrast to most other large marine ecosystems, cephalopods found in the Greater North Sea and the Celtic Seas regions appear to contribute only a small fraction to the diets of ecologically important finfish (found in the stomachs of ~14% of specimens among some species, but generally only 1–3% in most species), though their role as predator may be important and require further investigation. Based on our findings, cephalopods may not represent a key component for integrated ecosystem assessments, though as squid populations have been shown to expand throughout the North Sea in recent years, regular monitoring is encouraged to identify the point where their inclusion into such models may be necessary

Distributed Generation and Resilience in Power Grids

We study the effects of the allocation of distributed generation on the resilience of power grids. We find that an unconstrained allocation and growth of the distributed generation can drive a power grid beyond its design parameters. In order to overcome such a problem, we propose a topological algorithm derived from the field of Complex Networks to allocate distributed generation sources in an existing power grid.Comment: proceedings of Critis 2012 http://critis12.hig.no