Two-fluid and magnetohydrodynamic modelling of magnetic reconnection in the MAST spherical tokamak and the solar corona

Twisted magnetic flux ropes are ubiquitous in space and laboratory plasmas, and the merging of such flux ropes through magnetic reconnection is an important mechanism for restructuring magnetic fields and releasing free magnetic energy. The merging-compression scenario is one possible start up scheme for spherical tokamaks, which has been used on the Mega Amp Spherical Tokamak MAST. Two current-carrying plasma rings, or flux ropes, approach each other through the mutual attraction of their like currents, and merge, through magnetic reconnection, into a single plasma torus, with substantial plasma heating. 2D resistive MHD and Hall MHD simulations of this process are reported, and new results for the temperature distribution of ions and electrons are presented. A model of the based on relaxation theory is also described, which is now extended to tight aspect ratio geometry. This model allows prediction of the final merged state and the heating. The implications of the relaxation model for heating of the solar corona are also discussed, and a model of the merger of two or more twisted coronal flux ropes is presented, allowing for different senses of twist

Tachinid Fly Parasitism and Phenology of the Neotropical Red-Shouldered Stink Bug, Thyanta perditor (F.) (Heteroptera: Pentatomidae), on the Wild Host Plant, Bidens pilosa L. (Asteraceae).

Field and laboratory studies were conducted with the Neotropical redshouldered stink bug Thyanta perditor (F.) (Heteroptera: Pentatomidae) aiming to evaluate parasitismincidence on adults by tachinid flies (Diptera: Tachinidae), which were raised in the laboratory for identification. Egg deposition by flies on adult body surface was mapped. In addition, nymph and adult incidence on the wild host plant black jack, Bidens pilosa L. (Asteraceae), during the vegetative and the reproductive periods of plant development was studied. Seven species of tachinid flies were obtained: Euthera barbiellini Bezzi (73% of the total) and Trichopoda cf. pictipennis Bigot (16.7%) were the most abundant; the remaining five species, Gymnoclytia sp.; Phasia sp.; Strongygaster sp.; Cylindromyia cf. dorsalis (Wiedemann); and Ectophasiopsis ypiranga Dios & Nihei added 10.3% of the total. Tachinid flies parasitism on T. perditor adults was significantly greater on the dorsal compared to the ventral body surface. On the dorsal surface, the pronotum was significantly preferred and the wings the least preferred site. No differences were observed on the number of tachinid fly eggs deposited on wings, considering the ?under? and ?above? sites. Results indicated a significantly greater number of nymphs on mature compared to immature seeds. Adults significantly preferred immature compared to mature seeds; both were less abundant on leaves/stems and inflorescences

Irrigação na cultura do alho.

bitstream/item/121069/1/CT-136.pd

Effect of green-belly stink bug, Dichelops furcatus (F.) on wheat yield and development.

Made available in DSpace on 2017-04-28T23:48:19Z (GMT). No. of bitstreams: 1 ID439242016v79CropProtection.pdf: 1075995 bytes, checksum: 6b09a11cbae72fe37816cffeb808e599 (MD5) Previous issue date: 2017-02-03201

Confining strings in SU(N) gauge theories

We calculate the string tensions of $k$-strings in SU($N$) gauge theories in both 3 and 4 dimensions. In D=3+1, we find that the ratio of the $k=2$ string tension to the $k = 1$ fundamental string tension is consistent, at the $2 \sigma$ level, with both the M(-theory)QCD-inspired conjecture and with `Casimir scaling'. In D=2+1 we see a definite deviation from the MQCD formula, as well as a much smaller but still significant deviation from Casimir scaling. We find that in both D=2+1 and D=3+1 the high temperature spatial $k$-string tensions also satisfy approximate Casimir scaling. We point out that approximate Casimir scaling arises naturally if the cross-section of the flux tube is nearly independent of the flux carried, and that this will occur in an effective dual superconducting description, if we are in the deep-London limit. We estimate, numerically, the intrinsic width of $k$-strings in D=2+1 and indeed find little variation with $k$. In addition to the stable $k$-strings we investigate some ofthe unstable strings, finding in D=2+1 that they satisfy (approximate) Casimir scaling. We also investigate the basic assumption that confining flux tubes are described by an effective string theory at large distances. We estimate the coefficient of the universal L\"uscher correction from periodic strings that are longer than 1 fermi, and find $c_L=0.98(4)$ in D=3+1 and $c_L=0.558(19)$ in D=2+1. These values are within $2 \sigma$ of the simple bosonic string values and are inconsistent with other simple effective string theories.Comment: 57 pages, 11 figures. Errors on fits reduced by altering the analysis to a standard one. Conclusions unchanged; note addedchanged. Some typos correcte

Autonomic nervous system responses to strength training in top-level weight lifters

In athletes, spectral analysis of HR variability (HRV) has been shown capable to detect the adaptational changes in sympatho-vagal control attending physical training. So far, studies investigated autonomic nervous system (ANS) changes occurring with endurance training, whereas adaptations to markedly different exercise modes, for example, strength training, have never been investigated. We assessed the changes in cardiac ANS parameters during long-term training in weight lifters of the Italian team preparing for the European Championship, where athletes competed for obtaining the pass for Olympic Games. We investigated nine athletes. Subject trained 3 sessions/day, 6 days a week. The intensity of strength exercises varied from 70% to 95% 1 RM. Training load (TL) was calculated as: volume (min)  7 intensity (%1RM).All ANS parameters were significantly and highly correlated on an individual basis to the dose of exercise with a second-order regression model (r2 ranged from 0.96 to 0.99; P < 0.001). The low-frequency (LF) component of HRV and LF/HF ratio showed an initial increase with the progression of TL and then a decrease, resembling a bell-shaped curve with a minimum at the highest TL. The high-frequency (HF) component of HRV and R-R interval showed a reciprocal pattern, with an initial decrease with progression of TL followed by an increase, resembling an U-shaped curve with a maximum at the highest TL. These adaptations were at the opposite to those previously reported in endurance athletes. These results suggest that in Olympic weight lifters, ANS adaptations to training are dose-related on individual basis and that ANS adaptations are mainly sport-specific

Foliar application of different vegetal-derived protein hydrolysates distinctively modulates tomato root development and metabolism

Despite the scientific evidence supporting their biostimulant activity, the molecular mechanism(s) underlying the activity of protein hydrolysates (PHs) and the specificity among different products are still poorly explored. This work tested five different protein hydrolysates, produced from different plant sources using the same enzymatic approach, for their ability to promote rooting in tomato cuttings following quick dipping. Provided that all the different PHs increased root length (45\u201393%) and some of them increased root number (37\u201356%), untargeted metabolomics followed by multivariate statistics and pathway analysis were used to unravel the molecular processes at the basis of the biostimulant activity. Distinct metabolomic signatures could be found in roots following the PHs treatments. In general, PHs shaped the phytohormone profile, modulating the complex interaction between cytokinins and auxins, an interplay playing a pivotal role in root development, and triggered a down accumulation of brassinosteroids. Concerning secondary metabolism, PHs induced the accumulation of aliphatic glucosinolates, alkaloids, and phenylpropanoids, potentially eliciting crop resilience to stress conditions. Here, we confirm that PHs may have a hormone-like activity, and that their application can modulate plant growth, likely interfering with signaling processes. Noteworthy, the heterogenicity of the botanical origin supported the distinctive and peculiar metabolomic responses we observed across the products tested. While supporting their biostimulant activity, these findings suggest that a generalized crop response to PHs cannot be defined and that specific effects are rather to be investigated

Towards the glueball spectrum from unquenched lattice QCD

We use a variational technique to study heavy glueballs on gauge configurations generated with 2+1 flavours of ASQTAD improved staggered fermions. The variational technique includes glueball scattering states. The measurements were made using 2150 configurations at 0.092 fm with a pion mass of 360 MeV. We report masses for 10 glueball states. We discuss the prospects for unquenched lattice QCD calculations of the oddballs.Comment: 19 pages, 4 tables and 8 figures. One figure added. Now matches the published versio