Resummation of infrared divergences in the free-energy of spin-two fields

We derive a closed form expression for the sum of all the infrared divergent contributions to the free-energy of a gas of gravitons. An important ingredient of our calculation is the use of a gauge fixing procedure such that the graviton propagator becomes both traceless and transverse. This has been shown to be possible, in a previous work, using a general gauge fixing procedure, in the context of the lowest order expansion of the Einstein-Hilbert action, describing non-interacting spin two fields. In order to encompass the problems involving thermal loops, such as the resummation of the free-energy, in the present work, we have extended this procedure to the situations when the interactions are taken into account.Comment: 12 pages, 25 figure

Carbon and Nitrogen Stocks in Integrated Crop Livestock

Soil organic matter (SOM) is recognized as an important characteristic of sustainable agricultural systems in the tropics and temperate regions. It is considered an integrated characteristic of physical, chemical and biological soil conditions and has been used as a soil quality index in different land uses and management practices (Lal 2011). Environmental, social, and financial imbalances have occurred, requiring producers to become more efficient. A system of intercropping grain crops with forages can provide enough forage in the dry season to maintain nutritional quality of livestock and even promote weight gain (Castro Filho et al. 1991). An integrated crop-livestock system (ICLS) that includes a crop phase and a pasture phase in rotation has strong potential for sustainable beef and grain crop production (Salton et al. 2011). Perennial pastures can contribute to soil C sequestration. Several studies have shown significant soil organic C accumulation with well-managed grazing of pastures (Maia et al. 2009; Salton et al. 2011). However, there are few studies that compare the efficiency of different grasses to maintain productivity and promote an increase in soil organic C and stocks. We hypothesized that an ICLS with maize cultivated under no-tillage in rotation with grazed pasture (Urochloa P. Beauv. spp. (syn. Brachiaria (Trin.) Griseb. spp.) would result in accumulation of soil organic C and N compared with continuously grazed, degraded pasture or with conventionally tilled monoculture production of maize. Our objective was to evaluate the stocks of soil organic C and N under alternative land uses from the prevailing degraded pasture condition in Sao Paulo state of Brazil

PCR-based detection of Babesia bovis and Babesia bigemina in their natural host Boophilus microplus and cattle.

PCR and nested-PCR methods were used to assess the frequency of Babesia bovis and Babesia bigemina infection in Boophilus microplus engorged females and eggs and in cattle reared in an area with endemic babesiosis. Blood and the engorged female ticks were from 27 naturally infested calves and 25 crossbred cows. The frequency of both Babesia species was similar in calves and cows (P>0.05). Babesia bovis was detected in 23 (85.2%) calves and in 25 (100%) cows and B. bigemina was detected in 25 (92.6%) calves and in 21 (84%) cows. Mixed infections with the both Babesia species were identified in 42 animals, 21 in each age category. Of female ticks engorged on calves, 34.9% were negative and single species infection with B. bigemina (56.2%) was significantly more frequent (P0.05) to the frequency of single B. bigemina infection (15.9%). Mixed Babesia infection was lower (P<O.OI) than single species infection in female ticks engorged either in cows (5.7%) or in calves (4.3%). An egg sample from each female was analysed for the presence of Babesia species. Of the egg samples from female ticks infected with B. bovis, 26 (47.3%) were infected while from those from female ticks infected with B. bigemina 141 (76.6%) were infected (P<0.01). The results showed that although the frequency of both species of Babesia was similar in calves and cows, the infectivity of B. bigemina was higher to ticks fed on calves while to those ticks fed on cows the infectivity of both Babesia species was similar

International survey of Cronobacter sakazakii and other Cronobacter spp. in follow up formulas and infant food

A coordinated survey for Cronobacter and related organisms in powdered infant formula, follow up formula and infant foods was undertaken by 8 laboratories in 7 countries in recognition of and in response to the data needs identified in an FAO/WHO call for data in order to develop global risk management guidance for these products. The products (domestic and imported) were purchased from the local market and were categorised according to their principle ingredients. A total of 290 products were analysed using a standardised procedure of pre-enrichment in 225 ml Buffered Peptone Water (BPW), followed by enrichment in Enterobacteriaceae Enrichment (EE) broth, plating on the chromogenic Cronobacter Druggan–Forsythe–Iversen (DFI) agar and presumptive identification with ID 32 E. Presumptive Cronobacter isolates were identified using 16S rRNA gene sequence analysis. Aerobic plate counts (APC) of the products were also determined on nutrient agar. Fourteen samples had APC > 105 cfu/g, 3 of which contained probiotic cultures. C. sakazakii was isolated from 27 products; 3/91 (3%) follow up formulas (as defined by Codex Alimentarius Commission), and 24/199 (12%) infant foods and drinks. Hence C. sakazakii was less prevalent in follow up formula than other foods given to infants over the same age range. A range of other bacteria were also isolated from follow up formulas, including Acinetobacter baumannii, Enterobacter cloacae, Klebsiella pneumoniae, Citrobacter freundii, and Serratia ficaria. There was significant variation in the reconstitution instructions for follow up formulas. These included using water at temperatures which would enable bacterial growth. Additionally, the definition of follow up formula varied between countries

First stars XVI. STIS/HST abundances of heavy-elements in the uranium-rich star CS 31082-001

Detailed abundances of the elements produced by r-process nucleosynthesis in various circumstances are our best observational clues to their origin, since the site(s) of r-element production is(are) still not known with certainty. A small fraction of extremely metal-poor (EMP) stars exhibit excesses of heavy neutron-capture elements produced in the r-process, and CS 31082-001 is among the 4 well-known r-process-enhanced EMP stars. Observations with HST/STIS provide abundances for elements observable only from the UV region. Here we aim to supplement the optical data with abundances from near-UV spectroscopy of the first and second peak of the r-elements, which are crucial to giving insight into the nucleosynthesis of the elements beyond iron. The UVES spectrum provided additional measurements, thereby improving the previous results. The spectra were analyzed with the OSMARCS LTE model atmosphere and with a consistent approach based on the spectrum synthesis code Turbospectrum to derive abundances of heavy elements in CS 31082-001, using updated oscillator strengths from the recent literature. We computed synthetic spectra for all lines of the elements of interest, checking for proper intensities and possible blends. We combined the abundances of heavy elements derived in previous works with the derivation of abundances from all reliable new list of lines, for the first and second peaks of r-elements. We were able to derive new abundances for 23 n-elements, 6 of them - Ge, Mo, Lu, Ta, W, and Re - were not available in previous works, making this star the most complete r-II object studied, with a total of 37 detections of n-capture elements. We also present the first NLTE+3D lead abundance in this star. The results provide improved constraints on the nature of the r-process.Comment: 20 pages, 21 figures, 3 tables. Accepted for publication in Astronomy and Astrophysic

Possible chiral phase transition in two-dimensional solid 3^3He

We study a spin system with two- and four-spin exchange interactions on the triangular lattice, which is a possible model for the nuclear magnetism of solid $^3$He layers. It is found that a novel spin structure with scalar chiral order appears if the four-spin interaction is dominant. Ground-state properties are studied using the spin-wave approximation. A phase transition concerning the scalar chirality occurs at a finite temperature, even though the dimensionality of the system is two and the interaction has isotropic spin symmetry. Critical properties of this transition are studied with Monte Carlo simulations in the classical limit.Comment: 4 pages, Revtex, 4 figures, to appear in Phys.Rev.Let

Synthesis, characterization and thermal behaviour of solid 2-methoxycinnamylidenepyruvate of light trivalent lanthanides

Solid state Ln-2-MeO-CP compounds, where Ln stands for light trivalent lanthanides (La, Ce, Pr, Nd, Sm, Eu, Gd) and 2-MeO-CP is 2-methoxycinnamylidenepyruvate, were synthesized in this work. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, experimental and theoretical infrared spectroscopy and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results led to information regarding the composition and stability of the isolated complexes

Desempenho de jundiás alimentados com fontes proteicas submetidas ou não a tratamento para remoção de antinutrientes.

O objetivo deste trabalho foi avaliar o desempenho de jundiás alimentados com diferentes fontes proteicas de origem vegetal, submetidas ou não a tratamento químico (lavagem com solução ácida, seguida de lavagem com etanol) para a remoção de fatores antinutricionais.Organizado por: Sílvio Ricardo Maurano; AQUACIÊNCIA 2012

Emissão de metano por bovinos de corte, suplementados ou não, em pastagem de capim mombaça(Panicum maximum cv. Mombaça). I-Perdas energéticas.

Objetivou-se avaliar o impacto da suplementação protéico-energética na emissão de metano (CH4) de novilhos, durante a recria, em pastagem de capim-mombaça. Os tratamentos avaliados foram: T0 ? Apenas suplementação mineral; T1 ? Suplementação protéico-energética. Utilizou-se a técnica do gás traçador interno hexafluoreto de enxofre (SF6) para estimar a emissão diária de CH4. Foram utilizados 20 animais, sendo dez de cada tratamento, em dois ensaios, com medição de CH4 em cinco dias consecutivos. Na análise estatística dos dados de emissão de CH4 , utilizou-se a metodologia de modelos mistos para medidas repetidas do SAS. Animais suplementados e não suplementados não diferiram (P>0,05) quanto à produção diária de metano e quanto à perda diária de energia na forma de CH4. Entretanto, quando a perda de energia foi expressa em g/kg de matéria seca consumida (21,51 vs. 29,76 g/kg) e como porcentagem da energia bruta (EB) ingerida (6,36 versus 8,59 %), os animais suplementados tiveram menores perdas (P 0.05) on the daily production of methane and on the daily loss of energy in the form of CH4. However, when energy loss was expressed in g/kg of dry matter intake (21.51 vs. 29.76 g/kg) or as a percentage of gross energy (GE) intake (6.36 versus 8.59 %), supplemented animals had smaller CH4 losses (P <0.05) than the non supplemented ones. It was concluded that concentrate supplementation can effectively mitigate methane emission