Determinação do carbono da biomassa microbiana do solo: Método da fumigação-extração.

Precondicionamento das amostras. Procedimento analítico. Cálculo da BMS.bitstream/CNPAB-2010/27227/1/doc037.pd

A Stimulated Raman Loss spectrometer for metrological studies of quadrupole lines of hydrogen isotopologues

We discuss layout and performance of a high-resolution Stimulated Raman Loss spectrometer that has been newly developed for accurate studies of spectral lineshapes and line center frequencies of hydrogen isotopologues and in general of Raman active transitions. Thanks to the frequency comb calibration of the detuning between pump and Stokes lasers and to an active alignment of the two beams, the frequency accuracy is well below 100 kHz. Over the vertical axis the spectrometer benefits from shot-noise limited detection, signal enhancement via multipass cell, active flattening of the spectral baseline and measurement times of few seconds over spectral spans larger than 10 GHz. Under these conditions an efficient averaging of Raman spectra is possible over long measurement times with minimal distortion of spectral lineshapes. By changing the pump laser, transitions can be covered in a very broad frequency span, from 50 to 5000 $\mathrm{cm^{-1}}$, including both vibrational and rotational bands. The spectrometer has been developed for studies of fundamental and collisional physics of hydrogen isotopologues and has been recently applied to the metrology of the Q(1) 1-0 line of $\mathrm{H_2}$

A stimulated Raman loss spectrometer for metrological studies of quadrupole lines of hydrogen isotopologues

We discuss layout and performance of a high-resolution Stimulated Raman Loss spectrometer that has been newly developed for accurate studies of spectral lineshapes and line centre frequencies of hydrogen isotopologues and in general of Raman active transitions. Thanks to the frequency comb calibration of the detuning between pump and Stokes lasers and to an active alignment of the two beams, the frequency accuracy is at a level of 50 kHz. Over the vertical axis the spectrometer benefits from shot-noise limited detection, signal enhancement via multipass cell, active flattening of the spectral baseline and measurement times of few seconds over spectral spans larger than 10 GHz. Under these conditions an efficient averaging of Raman spectra is possible over long measurement times with minimal distortion of spectral lineshapes. By changing the pump laser, transitions can be covered in a very broad frequency span, from 50 to 5000 cm−1, including both vibrational and rotational bands. The spectrometer has been developed for studies of fundamental and collisional physics of hydrogen isotopologues and has been recently applied to the metrology of the Q(1) 1–0 line of H2

Serosurvey of schmallenberg virus infection in sheep in Abruzzo, Italy : short report

Infection with Schmallenberg virus (SBV) causes congenital musculoskeletal and vertebral malformations as well as neurological failures in fetuses of several ruminant species. In this study 1038 sheep samples from 10 flocks in the provinces of Chieti, Teramo and Pescara in Italy have been tested for antibodies against SBV by ELISA test. The purpose of the study was to ascertain the extent of SBV infections in sheep in Italy. The results of the ELISA test identified at least one positive animal in 9 of the 10 sheep flocks tested, and a mean within-flock prevalence of 8.57%. Furthermore, large variability of positive animals between flocks was observed (0 and 42.5%). These results demonstrate that SBV was endemic in this region and there could be is a risk of novel SBV infections in the following lambing season, raising serious concerns about its so rapid and pervasive spread

Scanning Electron Microscope Cytochemistry of Blood Cells

The backscattered electron imaging (BEI) mode of scanning electron microscopy (SEM) has been applied to study various histo-cytochemical reactions in biological specimens since the early seventies. Due to numerous, recent technical improvements the BEI mode of SEM now belongs to the routine of many SEM laboratories. For cytochemistry, BEI has been mainly used to: visualize intracellular structures and organelles; recognize the different cell types in heterogeneous populations or tissues; study the correlations between enzymatic activities and cell surface features. We have evaluated the most relevant results obtained in the study of blood cells and the possible future applications of these techniques

Combinatorial Discriminant Analysis Applied to RNAseq Data Reveals a Set of 10 Transcripts as Signatures of Exposure of Cattle to Mycobacterium avium subsp. paratuberculosis

Paratuberculosis or Johne's disease in cattle is a chronic granulomatous gastroenteritis caused by infection with Mycobacterium avium subspecies paratuberculosis (MAP). Paratuberculosis is not treatable; therefore, the early identification and isolation of infected animals is a key point to reduce its incidence. In this paper, we analyse RNAseq experimental data of 5 ELISA-negative cattle exposed to MAP in a positive herd, compared to 5 negative-unexposed controls. The purpose was to find a small set of differentially expressed genes able to discriminate between exposed animals in a preclinical phase from non-exposed controls. Our results identified 10 transcripts that differentiate between ELISA-negative, clinically healthy, and exposed animals belonging to paratuberculosis-positive herds and negative-unexposed animals. Of the 10 transcripts, five (TRPV4, RIC8B, IL5RA, ERF, CDC40) showed significant differential expression between the three groups while the remaining 5 (RDM1, EPHX1, STAU1, TLE1, ASB8) did not show a significant difference in at least one of the pairwise comparisons. When tested in a larger cohort, these findings may contribute to the development of a new diagnostic test for paratuberculosis based on a gene expression signature. Such a diagnostic tool could allow early interventions to reduce the risk of the infection spreading

Ultrafast Energy Transfer in an Artificial Photosynthetic Antenna

We temporally resolved energy transfer kinetics in an artificial light- harvesting dyad composed of a phthalocyanine covalently linked to a carotenoid. Upon carotenoid photo-excitation, energy transfers within ≈100fs (≈52% efficiency) to the phthalocyanine

Stimulated Raman scattering metrology of molecular hydrogen

Frequency combs have revolutionized optical frequency metrology, allowing one to determine highly accurate transition frequencies of a wealth of molecular species. These progresses have only marginally benefited infrared-inactive transitions, due to their inherently weak cross-sections. Here we overcome this limitation by introducing stimulated-Raman-scattering metrology, where a frequency comb is exploited to calibrate the frequency detuning between the pump and Stokes excitation lasers. We apply this approach to the investigation of molecular hydrogen, which is a recognized benchmark for tests of quantum electrodynamics and of theories that describe physics beyond the standard model. Specifically, we measure the transition frequency of the Q(1) fundamental line of H2 around 4155 cm−1 with few parts-per-billion uncertainty, which is comparable to the theoretical benchmark of ab initio calculations and more than a decade better than the experimental state of the art. Our comb-calibrated stimulated Raman scattering spectrometer extends the toolkit of optical frequency metrology as it can be applied, with simple technical changes, to many other infrared-inactive transitions, over a 50-5000 cm−1 range that covers also purely rotational bands