1,260 research outputs found
Perfilhamento e caracterĂsticas morfolĂłgicas do capim-elefante anĂŁo sob pastejo
Morphological characteristics and tillering of dwarf elephantgrass (Pennisetum purpureum Schum.) were studied in a grazing trial conducted at the University at Florida - USA. The grass was subjected to the effects of two management factors, each at five levels as follows: length of grazing cycle (GC) (continuous grazing, 14, 28, 42 and 56 days) and grazing pressure (GP) (500, 1,000, 1,500, 2,000 and 2,500 kg at residual leaf dry matter ha-1). Response surface methodology was used to analyse the data. Increases in GC and decreases in GP increased plant height, apical meristems height, number of internodes and dry matter produced per tiller. The percentage of apical meristems eliminated was greater under continuous grazing and high GP. The number of axillary buds per tiller was depressed under high GP. Shorter internodes were observed at short GC and high GP. Primary tillers constituted the predominant from of tillering in this grass. The results obtained indicate that short grazing cycles and high grazing pressures should be avoided in the management of dwarf elephantgrass in order to insure persistence and productivity of the pasture.O perfilhamento e as caracterĂsticas morfolĂłgicas do capim-elefante anĂŁo (Pennisetum purpureum Schum.) foram estudados num ensaio de pastejo conduzido na Universidade da FlĂłrida - EUA. O capim foi submetido a 5 nĂveis de pressĂŁo de pastejo - PP (500, 1.000, 1.500, 2.000 e 2.500 kg de MS de folha residual hĂĄ-1 ) e ciclo de pastejo - CP (pastejo contĂnuo, 14, 28, 42 e 56 dias). Os dados foram analisados atravĂ©s da metodologia de superfĂcie de resposta. Aumentos no CP e reduçÔes na PP resultaram no aumento da altura das plantas e dos meristemas apicais, no nĂșmero de entrenĂłs por perfilho e na produç3o de MS produzida por perfilho. A percentagem de meristemas apicais eliminados foi mais elevada sob pastejo contĂnuo e alta PP. O nĂșmero de gemas axilares por perfilho foi reduzido sob alta PP. EntrenĂłs mais curtos foram observados em CP curtos e alta PP. Perfilhos primĂĄrios constituem a forma predominante de perfilhamento neste capim. Os resultados obtidos sugerem que CP curtos e altas PP devem ser evitados no manejo do capim-elefante anuo a fim de assegurar a persistĂȘncia e a produtividade da pastagem
Contribution of S6K1/MAPK signaling pathways in the response to oxidative stress: activation of RSK and MSK by hydrogen peroxide
Trobareu correccions de l'article a: http://dx.doi.org/10.1371/annotation/0b485bd9-b1b2-4c60-ab22-3ac5d271dc59Cells respond to different kind of stress through the coordinated activation of signaling pathways such as MAPK or p53. To find which molecular mechanisms are involved, we need to understand their cell adaptation. The ribosomal protein, S6 kinase 1 (S6K1), is a common downstream target of signaling by hormonal or nutritional stress. Here, we investigated the initial contribution of S6K1/MAPK signaling pathways in the cell response to oxidative stress produced by hydrogen peroxide (H2O2). To analyze S6K1 activation, we used the commercial anti-phospho-Thr389-S6K1 antibody most frequently mentioned in the bibliography. We found that this antibody detected an 80-90 kDa protein that was rapidly phosphorylated in response to H2O2 in several human cells. Unexpectedly, this phosphorylation was insensitive to both mTOR and PI3K inhibitors, and knock-down experiments showed that this protein was not S6K1. RSK and MSK proteins were candidate targets of this phosphorylation. We demonstrated that H2O2 stimulated phosphorylation of RSK and MSK kinases at residues that are homologous to Thr389 in S6K1. This phosphorylation required the activity of either p38 or ERK MAP kinases. Kinase assays showed activation of RSK and MSK by H2O2. Experiments with mouse embryonic fibroblasts from p38 animals" knockout confirmed these observations. Altogether, these findings show that the S6K1 signaling pathway is not activated under these conditions, clarify previous observations probably misinterpreted by non-specific detection of proteins RSK and MSK by the anti-phospho-Thr389-S6K1 antibody, and demonstrate the specific activation of MAPK signaling pathways through ERK/p38/RSK/MSK by H2O2
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Recent results on heavy-ion induced reactions of interest for neutrinoless double beta decay at INFN-LNS
Abstract. The possibility to use a special class of heavy-ion induced direct reactions, such as double charge exchange reactions, is discussed in view of their application to extract information that may be helpful to determinate the nuclear matrix elements entering in the expression of neutrinoless double beta decay halflife. The methodology of the experimental campaign presently running at INFN - Laboratori Nazionali del Sud is reported and the experimental challenges characterizing such activity are describe
NURE: An ERC project to study nuclear reactions for neutrinoless double beta decay
Neutrinoless double beta decay (0ÎœÎČÎČ) is considered the best potential resource to
access the absolute neutrino mass scale. Moreover, if observed, it will signal that neutrinos are
their own anti-particles (Majorana particles). Presently, this physics case is one of the most
important research âbeyond Standard Modelâ and might guide the way towards a Grand
Unified Theory of fundamental interactions.
Since the 0ÎœÎČÎČ decay process involves nuclei, its analysis necessarily implies nuclear structure
issues. In the NURE project, supported by a Starting Grant of the European Research Council
(ERC), nuclear reactions of double charge-exchange (DCE) are used as a tool to extract
information on the 0ÎœÎČÎČ Nuclear Matrix Elements. In DCE reactions and ÎČÎČ decay indeed the
initial and final nuclear states are the same and the transition operators have similar structure.
Thus the measurement of the DCE absolute cross-sections can give crucial information on ÎČÎČ
matrix elements. In a wider view, the NUMEN international collaboration plans a major
upgrade of the INFN-LNS facilities in the next years in order to increase the experimental
production of nuclei of at least two orders of magnitude, thus making feasible a systematic
study of all the cases of interest as candidates for 0ÎœÎČÎČ
Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences
The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & NemĂ©sio 2007; Donegan 2008, 2009; NemĂ©sio 2009aâb; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported
by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on
18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based
researchers who signed it in the short time span from 20 September to 6 October 2016
- âŠ