Significance of autoclaving-induced toxicity from and hydrolysis of carbohydrates in in vitro studies of pollen germination and tube growth

Autoclaving of various carbohydrates resulted in decreased in vitro pollen germination and/or pollen tube growth in species belonging to different families. This toxicity was eliminated by treatment of autoclaved sucrose and glucose solutions with activated charcoal. Autoclaving-induced hydrolysis of sucrose at pH6 resulted in stimulated Agapanthus praecox pollen growth (in detoxified media) probably due to the formation of glucose which was found to be a superior carbohydrate source for in vitro pollen growth in this species. Considering these results as well as previous reports on anther culture studies, autoclaving-induced toxicity from and hydrolysis of carbohydrates should be taken into account in all pollen and anther culture studies as well as in vitro pollination of ovules

Postgerminative growth and lipid catabolism in oilseeds lacking the glyoxylate cycle

The glyoxylate cycle is regarded as essential for postgerminative growth and seedling establishment in oilseed plants. We have identified two allelic Arabidopsis mutants, icl-1 and icl-2, which lack the glyoxylate cycle because of the absence of the key enzyme isocitrate lyase. These mutants demonstrate that the glyoxylate cycle is not essential for germination. Furthermore, photosynthesis can compensate for the absence of the glyoxylate cycle during postgerminative growth, and only when light intensity or day length is decreased does seedling establishment become compromised. The provision of exogenous sugars can overcome this growth deficiency. The icl mutants also demonstrate that the glyoxylate cycle is important for seedling survival and recovery after prolonged dark conditions that approximate growth in nature. Surprisingly, despite their inability to catalyze the net conversion of acetate to carbohydrate, mutant seedlings are able to break down storage lipids. Results suggest that lipids can be used as a source of carbon for respiration in germinating oilseeds and that products of fatty acid catabolism can pass from the peroxisome to the mitochondrion independently of the glyoxylate cycle. However, an additional anaplerotic source of carbon is required for lipid breakdown and seedling establishment. This source can be provided by the glyoxylate cycle or, in its absence, by exogenous sucrose or photosynthesis

External Operators and Anomalous Dimensions in Soft-Collinear Effective Theory

It has recently been argued that soft-collinear effective theory for processes involving both soft and collinear partons contains a new soft-collinear mode, which can communicate between the soft and collinear sectors of the theory. The formalism incorporating the corresponding fields into the effective Lagrangian is extended to include external current and four-quark operators relevant to weak interactions. An explicit calculation of the anomalous dimensions of these operators reveals that soft-collinear modes are needed for correctly describing the ultraviolet behavior of the effective theory.Comment: 15 pages, 2 figure

Review of available evidence regarding the vulnerability of off-crop non-target arthropod communities in comparison to in-crop non-target arthropod communities

EFSA is revising and updating the Ecotoxicology Guidance Document on Terrestrial Risk Assessment of Pesticides (SANCO/10329/2002). For this purpose an overview of available scientific information on several topics is needed. The aim of the current literature survey was to collect and summarize the published scientific literature on (1) the composition of non-target arthropod species that occur in and outside crops, (2) their vulnerability to pesticides and (3) their potential to recover from a pesticide impact. The survey was aimed at all major groups of non-target arthropods occurring in and outside crops. In order to collect relevant literature on-line searches in various databases were carried out in December 2011 and January 2012. The searches addressed two types of scientific information: (1) publications with the results of ecotoxicological field studies in which the effects of pesticides on in-field and off-field communities of non-target arthropod communities are investigated, and (2) publications with the results of ecological studies that describe and compare the composition of in-crop and off-crop communities of non-target arthropods. The literature searches initially yielded over 1,500 articles for which the abstracts were screened, but the number of suitable papers that was finally reviewed was less than 100. The taxonomic groups for which sufficient information was found were ground beetles (Carabidae), rove beetles (Staphylinidae), spiders (Aranea), hoverflies (Syrphidae) springtails (Collembola) and bugs (Heteroptera). Most studies of these groups were conducted in Europe and for the larger part in cereals. Types of off-crop habitats varied greatly (hedgerows, flower strips, grass edges, trees, etc.). For these taxonomic groups, the number of species and their abundance was higher in the off-crop habitat than in the crop. Most species were only found in one or a few studies, indicating that geographic location and specific crop and off-crop habitat are important factors determining the species composition. For other important non-target arthropod taxonomic groups, no suitable studies were found to evaluate in- and off-crop differences in species composition and abundance. These taxonomic groups include grasshoppers, butterflies, isopods, lady beetles, bees and wasps. The available literature was not suitable or contained very little information to assess the sensitivity to pesticides and recovery and thus the vulnerability of individual species from a pesticide impact in the field. Therefore an additional approach, vulnerability analysis based on species traits, was used. The analysis was done for a selection of thirteen species that represent the mentioned dominant taxonomic groups. This vulnerability analysis showed that for insecticides, herbicides and fungicides, the average vulnerability of typical off-crop species was higher than that of typical in-crop species. The average vulnerability of species that occur in both habitats was intermediate. The difference between off-crop and in-crop species can be explained by differences in exposure and especially recovery. In-crop species are less exposed (for instance because they breed out of the pesticide spraying season) and have a greater capacity to disperse, migrate and reproduce. It is plausible that such species are more typical of in-crop habitats because they are better adapted to the varying circumstances and frequent disturbances that occur within arable fields. In the same vulnerability analysis, the two current non-target arthropod standard test species, the parasitic wasp Aphidius rhopalosiphi and the predatory mite Typhlodromus pyri, were found to be the least vulnerable of all species analyse

Group descent algorithms for nonconvex penalized linear and logistic regression models with grouped predictors

Penalized regression is an attractive framework for variable selection problems. Often, variables possess a grouping structure, and the relevant selection problem is that of selecting groups, not individual variables. The group lasso has been proposed as a way of extending the ideas of the lasso to the problem of group selection. Nonconvex penalties such as SCAD and MCP have been proposed and shown to have several advantages over the lasso; these penalties may also be extended to the group selection problem, giving rise to group SCAD and group MCP methods. Here, we describe algorithms for fitting these models stably and efficiently. In addition, we present simulation results and real data examples comparing and contrasting the statistical properties of these methods

Five patients with biochemical and/or clinical generalized glucocorticoid resistance without alterations in the glucocorticoid receptor gene

Cortisol resistance (CR) is a rare disease characterized by a generalized reduced sensitivity of end-organs to the actions of glucocorticoids (GCs)

Modeling of prolactin response following dopamine D-2 receptor antagonists in rats: can it be translated to clinical dosing?

Pharmacolog

On the Initial Conditions for Brane Inflation

String theory gives rise to various mechanisms to generate primordial inflation, of which ``brane inflation'' is one of the most widely considered. In this scenario, inflation takes place while two branes are approaching each other, and the modulus field representing the separation between the branes plays the role of the inflaton field. We study the phase space of initial conditions which can lead to a sufficiently long period of cosmological inflation, and find that taking into account the possibility of nonvanishing initial momentum can significantly change the degree of fine tuning of the required initial conditions.Comment: 11 pages, 2 figure

The hyperfine transition in light muonic atoms of odd Z

The hyperfine (hf) transition rates for muonic atoms have been re-measured for select light nuclei, using neutron detectors to evaluate the time dependence of muon capture. For $^{19}$F $\Lambda$$_{h}$ = 5.6 (2) $\mu$s$^{-1}$ for the hf transition rate, a value which is considerably more accurate than previous measurements. Results are also reported for Na, Al, P, Cl, and K; that result for P is the first positive identification.Comment: 12 pages including 5 tables and 4 figures, RevTex, submitted to Phys. Rev.