Measurement of the branching ratio for beta-delayed alpha decay of 16N

While the 12C(a,g)16O reaction plays a central role in nuclear astrophysics, the cross section at energies relevant to hydrostatic helium burning is too small to be directly measured in the laboratory. The beta-delayed alpha spectrum of 16N can be used to constrain the extrapolation of the E1 component of the S-factor; however, with this approach the resulting S-factor becomes strongly correlated with the assumed beta-alpha branching ratio. We have remeasured the beta-alpha branching ratio by implanting 16N ions in a segmented Si detector and counting the number of beta-alpha decays relative to the number of implantations. Our result, 1.49(5)e-5, represents a 24% increase compared to the accepted value and implies an increase of 14% in the extrapolated S-factor

Amperometric and spectrophotometric determination of carbaryl in natural waters and commercial formulations

The work presented describes the development and evaluation of two flow-injection analysis (FIA) systems for the automated determination of carbaryl in spiked natural waters and commercial formulations. Samples are injected directly into the system where they are subjected to alkaline hydrolysis thus forming 1-naphthol. This product is readily oxidised at a glassy carbon electrode. The electrochemical behaviour of 1-naphthol allows the development of an FIA system with an amperometric detector in which 1-naphthol determination, and thus measurement of carbaryl concentration, can be performed. Linear response over the range 1.0×10–7 to 1.0×10–5 mol L–1, with a sampling rate of 80 samples h–1, was recorded. The detection limit was 1.0×10–8 mol L–1. Another FIA manifold was constructed but this used a colorimetric detector. The methodology was based on the coupling of 1-naphthol with phenylhydrazine hydrochloride to produce a red complex which has maximum absorbance at 495 nm. The response was linear from 1.0×10–5 to 1.5×10–3 mol L–1 with a detection limit of 1.0×10–6 mol L–1. Sample-throughput was about 60 samples h–1. Validation of the results provided by the two FIA methodologies was performed by comparing them with results from a standard HPLC–UV technique. The relative deviation was <5%. Recovery trials were also carried out and the values obtained ranged from 97.0 to 102.0% for both methods. The repeatability (RSD, %) of 12 consecutive injections of one sample was 0.8% and 1.6% for the amperometric and colorimetric systems, respectively

Quadro citológico vaginal, concentração plasmática de progesterona durante a gestação e medidas fetais em paca (Cuniculus paca Linnaeus, 1766).

Em 27 pacas (Cuniculus paca Linnaeus, 1766) objetivou-se descrever aos 30, 60 e 90 dias (D) de prenhez diagnosticada por ultrassonografia (US), os tipos celulares do epitélio vaginal em esfregaços vaginais, relatar as condições de abertura da vulva e as características do muco vaginal, determinar a concentração plasmática de progesterona (P4) por radioimunoensaio, e ainda, mensurar por ultrassonografia (US) o diâmetro biparietal (DBP) fetal aos 60 e 90 dias de prenhez. No D30, 40% das amostras exibiram células (com características estrogênicas) superficiais e presença de núcleos nus. Nos D60 e D90, células parabasais, intermediárias, superficiais e naviculares estavam presentes nas mesmas proporções, mas células endocervicais foram descritas em apenas 73,9% e 69% das amostras daqueles dias, respectivamente. No D30 a maior proporção de células naviculares e superficiais diferiu (p < 0,05) em relação aos outros tipos celulares presentes. O muco vaginal apresentou-se cristalino e fluido em 100% e em 70% das fêmeas nos D30 e D60, respectivamente. Observou-se o vestíbulo vaginal aberto em torno de 50% das fêmeas em todos os dias de exames. Valores mínimos detectáveis de P4 foram obtidos em 72% e em 83% das fêmeas, enquanto que as médias das medidas dos DBP foram 1,25 cm (± 0,16) e 2,34 cm (± 0,25) nos D60 e D90, respectivamente. O quadro citológico vaginal nos D30, D60 e D90 e o DBP fornecem elementos que contribuem para diagnóstico de gestação em pacas. A concentração de P4 demonstra a necessidade de maiores estudos da endocrinologia da gestação em pacas

Presence of antibody anti-Corynebacterium pseudotuberculosis in sheep in Dormentes state fo Pernambuco, Brazil.

The Northeast has the largest Brazilian herd of goat sand sheep. Approximately 60% of these animais are located on small farms, on this fact, are the major health problems of which still exist in this region

Avaliation of antibody anti-Corynebacterium pseudotuberculosis in goats milking of Sisal area in state of Bahia.

To evaluate the presence of antibodies of these bacteria,we used 305 animais of both sexes, various breeds, older than sixmonts from 25 dairy herds located in different municipalities of the Territory of Sisal,State of Bahia

Analysis of the evolution of hake (Merluccius hubbsi and Merluccius australis) catch and effort by Spanish vessels operating in the Patagonian shelf area since the beginning of this industrial fishery

The hake fishery (Merluccius hubbsi and Merluccius australis) is one of the most important ones for Spanish vessels operating in the Southwest Atlantic. Both species are widely distributed along the Patagonian shelf, although M. australis occupies mainly more southern waters. This paper presents a historical review of fishery data on the Spanish fishing fleet operating in the SW Atlantic collected and collated during the EC Study Project 99/016 “Data collection for stock assessment of two hakes (Merluccius hubbsi and M. australis) in International and Falkland waters of the SW Atlantic”, in order to analyse the evolution of catch and effort in the hake fishery since 1983 to 2000. Data on landings and effort by Spanish vessels from 1983 onwards were utilised to study trends and shifts within the fishery. These data were provided by Asociación Nacional de Armadores de Buques Congeladores de Pesca de Merluza (ANAMER), the most important Spanish ship-owners fishing association operating in distant fishing grounds. Catch and effort data collected by observer’s programmes carried out by Instituto Español de Oceanografía (IEO) and the Falkland Islands Government Fisheries Department (FIGFD), as well as by observers provided by the project were used to estimate CPUE by area and season.The data included landings in kgs by commercial size category of hake (both species together) and effort made by vessels appertaining to ANAMER in number of fishing days and number of vessels by vessel size category. Conversion factors obtained by scientific observers onboard of these vessels were used to obtain the whole catch from landings. Total effort of the Spanish fleet was estimated from ANAMER logbooks, assuming a similar pattern for the whole fleet and taking into account the different ratio of ANAMER fleet compared to the total Spanish fleet. An increase of the catches and effort was observed from 1983 to a maximum in 1990 coinciding with the closure of Namibian fisheries. After that, catches and effort decreased corresponding to the development of the Greenland halibut fishery in the NW Atlantic, until its stabilisation from 1993. CPUE showed different patterns of fishing activity by area and season

Differences between <i>Trypanosoma brucei gambiense</i> groups 1 and 2 in their resistance to killing by Trypanolytic factor 1

&lt;p&gt;&lt;b&gt;Background:&lt;/b&gt; The three sub-species of &lt;i&gt;Trypanosoma brucei&lt;/i&gt; are important pathogens of sub-Saharan Africa. &lt;i&gt;T. b. brucei&lt;/i&gt; is unable to infect humans due to sensitivity to trypanosome lytic factors (TLF) 1 and 2 found in human serum. &lt;i&gt;T. b. rhodesiense&lt;/i&gt; and &lt;i&gt;T. b. gambiense&lt;/i&gt; are able to resist lysis by TLF. There are two distinct sub-groups of &lt;i&gt;T. b. gambiense&lt;/i&gt; that differ genetically and by human serum resistance phenotypes. Group 1 &lt;i&gt;T. b. gambiense&lt;/i&gt; have an invariant phenotype whereas group 2 show variable resistance. Previous data indicated that group 1 &lt;i&gt;T. b. gambiense&lt;/i&gt; are resistant to TLF-1 due in-part to reduced uptake of TLF-1 mediated by reduced expression of the TLF-1 receptor (the haptoglobin-hemoglobin receptor (&lt;i&gt;HpHbR&lt;/i&gt;)) gene. Here we investigate if this is also true in group 2 parasites.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Methodology:&lt;/b&gt; Isogenic resistant and sensitive group 2 &lt;i&gt;T. b. gambiense&lt;/i&gt; were derived and compared to other T. brucei parasites. Both resistant and sensitive lines express the &lt;i&gt;HpHbR&lt;/i&gt; gene at similar levels and internalized fluorescently labeled TLF-1 similar fashion to &lt;i&gt;T. b. brucei&lt;/i&gt;. Both resistant and sensitive group 2, as well as group 1 &lt;i&gt;T. b. gambiense&lt;/i&gt;, internalize recombinant APOL1, but only sensitive group 2 parasites are lysed.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Conclusions:&lt;/b&gt; Our data indicate that, despite group 1 &lt;i&gt;T. b. gambiense&lt;/i&gt; avoiding TLF-1, it is resistant to the main lytic component, APOL1. Similarly group 2 &lt;i&gt;T. b. gambiense&lt;/i&gt; is innately resistant to APOL1, which could be based on the same mechanism. However, group 2 &lt;i&gt;T. b. gambiense&lt;/i&gt; variably displays this phenotype and expression does not appear to correlate with a change in expression site or expression of &lt;i&gt;HpHbR&lt;/i&gt;. Thus there are differences in the mechanism of human serum resistance between &lt;i&gt;T. b. gambiense&lt;/i&gt; groups 1 and 2.&lt;/p&gt

Condições ambientais e geográficas associadas à conservação genética do louro-pardo.

Resumo

Electrochemically Reconfigurable Architected Materials

Architected materials can actively respond to external stimuli—such as mechanical forces, hydration and magnetic fields—by changing their geometries and thereby achieve novel functionalities. Such transformations are usually binary and volatile because they toggle between ‘on’ and ‘off’ states and require persistent external stimuli. Here we develop three-dimensional silicon-coated tetragonal microlattices that transform into sinusoidal patterns via cooperative beam buckling in response to an electrochemically driven silicon-lithium alloying reaction. In situ microscopy reveals a controllable, non-volatile and reversible structural transformation that forms multiple ordered buckling domains separated by distorted domain boundaries. We investigate the mechanical dynamics of individual buckling beams, cooperative coupling among neighbouring beams, and lithiation-rate-dependent distributions of domain sizes through chemo-mechanical modelling and statistical mechanics analysis. Our results highlight the critical role of defects and energy fluctuations in the dynamic response of architected materials. We further demonstrate that domain boundaries can be programmed to form particular patterns by pre-designing artificial defects, and that a variety of reconfigurational degrees of freedom can be achieved through micro-architecture design. This framework enables the design, fabrication, modelling, behaviour prediction and programming of electrochemically reconfigurable architected materials, and could open the way to beyond-intercalation battery electrodes, tunable phononic crystals and bio-implantable devices