2,723 research outputs found
A feasibility study with survival in swine model
Transrectal access still has some unsolved issues such as spatial orientation,
infection, access and site closure. This study presents a simple technique to
perform transcolonic access with survival in a swine model series. A new
technique for NOTES perirectal access to perform retroperitoneoscopy,
peritoneoscopy, liver and lymphnode biopsies was performed in 6 pigs, using
Totally NOTES technique. The specimens were extracted transanally. The
flexible endoscope was inserted through a posterior transmural incision and
the retrorectal space. Cultures of bacteria were documented for the
retroperitoneal space and intra abdominal cavity after 14 days. Rectal site
was closed using non-absorbable sutures. There was no bowel cleansing, nor
preoperative fasting. The procedures were performed in 6 pigs through
transcolonic natural orifice access using available endoscopic flexible
instruments. All animals survived 14 days without complications, and cultures
were negative. Histopathologic examination of the rectal closure site showed
adequate healing of suture line and no micro abscesses. The results of
feasibility and safety of experimental Transcolonic NOTES potentially brings
new frontiers and future wider applications for minimally invasive surgery.
The treatment of colorectal, abdominal and retroperitoneal diseases through a
flexible Perirectal NOTES Access (PNA) is a promising new approach
Topological speckles
The time evolution of a topological Su-Schrieffer-Heeger chain is analyzed
through the statistics of speckle patterns. The emergence of topological edge
states dramatically affects the dynamical fluctuations of the wavefunction. The
intensity statistics is found to be described by a family of noncentral
chi-squared distributions, with the noncentrality parameter reflecting on the
degree of edge-state localization. The response of the speckle contrast with
respect to the dimerization of the chain is explored in detail as well as the
role of chiral symmetry-breaking disorder, number of edge states, their energy
gap, and the locations between which the transport occurs. In addition to
providing a venue for speckle customization, our results appeal to the use of
speckle patterns for characterization of nontrivial topological properties.Comment: 6 pages, 4 figure
Plant traits controlling growth change in response to a drier climate
This is the final version. Available on open access from Wiley via the DOI in this recordPlant traits are increasingly being used to improve prediction of plant function, including plant demography. However, the capability of plant traits to predict demographic rates remains uncertain, particularly in the context of trees experiencing a changing climate. Here we present data combining 17 plant traits associated with plant structure, metabolism and hydraulic status, with measurements of long-term mean, maximum and relative growth rates for 176 trees from the world’s longest running tropical forest drought experiment. We demonstrate that plant traits can predict mean annual tree growth rates with moderate explanatory power. However, only combinations of traits associated more directly with plant functional processes, rather than more commonly employed traits like wood density or leaf mass per area, yield the power to predict growth. Critically, we observe a shift from growth being controlled by traits related to carbon cycling (assimilation and respiration) in well-watered trees, to traits relating to plant hydraulic stress in drought-stressed trees. We also demonstrate that even with a very comprehensive set of plant traits and growth data on large numbers of tropical trees, considerable uncertainty remains in directly interpreting the mechanisms through which traits influence performance in tropical forests.Conselho Nacional de Desenvolvimento Científico e TecnológicoNatural Environment Research Council (NERC)Australian Research Council (ARC)European Union FP7Fundação de Amparo à Pesquisa do Estado de São Paul
GenSeed-HMM: A tool for progressive assembly using profile HMMs as seeds and its application in Alpavirinae viral discovery from metagenomic data
This work reports the development of GenSeed-HMM, a program that implements seed-driven progressive assembly, an approach to reconstruct specific sequences from unassembled data, starting from short nucleotide or protein seed sequences or profile Hidden Markov Models (HMM). The program can use any one of a number of sequence assemblers. Assembly is performed in multiple steps and relatively few reads are used in each cycle, consequently the program demands low computational resources. As a proof-of-concept and to demonstrate the power of HMM-driven progressive assemblies, GenSeed-HMM was applied to metagenomic datasets in the search for diverse ssDNA bacteriophages from the recently described Alpavirinae subfamily. Profile HMMs were built using Alpavirinae-specific regions from multiple sequence alignments using either the viral protein 1 (VP1) (major capsid protein) or VP4 (genome replication initiation protein). These profile HMMs were used by GenSeed-HMM (running Newbler assembler) as seeds to reconstruct viral genomes from sequencing datasets of human fecal samples. All contigs obtained were annotated and taxonomically classified using similarity searches and phylogenetic analyses. The most specific profile HMM seed enabled the reconstruction of 45 partial or complete Alpavirinae genomic sequences. A comparison with conventional (global) assembly of the same original dataset, using Newbler in a standalone execution, revealed that GenSeed-HMM outperformed global genomic assembly in several metrics employed. This approach is capable of detecting organisms that have not been used in the construction of the profile HMM, which opens up the possibility of diagnosing novel viruses, without previous specific information, constituting a de novo diagnosis. Additional applications include, but are not limited to, the specific assembly of extrachromosomal elements such as plastid and mitochondrial genomes from metagenomic data. Profile HMM seeds can also be used to reconstruct specific protein coding genes for gene diversity studies, and to determine all possible gene variants present in a metagenomic sample. Such surveys could be useful to detect the emergence of drug-resistance variants in sensitive environments such as hospitals and animal production facilities, where antibiotics are regularly used. Finally, GenSeed-HMM can be used as an adjunct for gap closure on assembly finishing projects, by using multiple contig ends as anchored seeds
The youngest massive protostars in the Large Magellanic Cloud
We demonstrate the unique capabilities of Herschel to study very young
luminous extragalactic young stellar objects (YSOs) by analyzing a central
strip of the Large Magellanic Cloud obtained through the HERITAGE Science
Demonstration Program. We combine PACS 100 and 160, and SPIRE 250, 350, and 500
microns photometry with 2MASS (1.25-2.17 microns) and Spitzer IRAC and MIPS
(3.6-70 microns) to construct complete spectral energy distributions (SEDs) of
compact sources. From these, we identify 207 candidate embedded YSOs in the
observed region, ~40% never-before identified. We discuss their position in
far-infrared color-magnitude space, comparing with previously studied,
spectroscopically confirmed YSOs and maser emission. All have red colors
indicating massive cool envelopes and great youth. We analyze four example
YSOs, determining their physical properties by fitting their SEDs with
radiative transfer models. Fitting full SEDs including the Herschel data
requires us to increase the size and mass of envelopes included in the models.
This implies higher accretion rates (greater than or equal to 0.0001 M_sun/yr),
in agreement with previous outflow studies of high-mass protostars. Our results
show that Herschel provides reliable longwave SEDs of large samples of
high-mass YSOs; discovers the youngest YSOs whose SEDs peak in Herschel bands;
and constrains the physical properties and evolutionary stages of YSOs more
precisely than was previously possible.Comment: Main text: 4 pages, 3 figures, 1 table; Online material: 3 figures, 1
table; to appear in the A&A Herschel Special Issu
Velocity Dispersion of Excited H2
We present a study of the high rotational bands (J > 2) of H2 toward 4 early
type galactic stars: HD 73882, HD 192639, HD 206267, and HD 207538. In each
case, the velocity dispersion - characterized by the spectrum fitting parameter
b - increases with the level of excitation, a phenomenon that has previously
been detected by the Copernicus and IMAPS observatories. In particular, we show
with 4 sigma confidence that for HD 192639 it is not possible to fit all J
levels with a single b value, and that higher b values are needed for the
higher levels. The amplitude of the line broadening, which can be as high as 10
km s^-1, makes explanations such as inhomogeneous spatial distribution
unlikely. We investigate a mechanism in which the broadening is due to the
molecules that are rotationally excited through the excess energy acquired
after their formation on a grain (H2-formation pumping). We show that different
dispersions would be a natural consequence of this mechanism. We note however
that such process would require a formation rate 10 times higher then what was
inferred from other observations. In view of the difficulty to account for the
velocity dispersion as thermal broadening (T would be around 10,000 K), we
conclude then that we are most certainly observing some highly turbulent warm
layer associated with the cold diffuse cloud. Embedded in a magnetic field, it
could be responsible for the high quantities of CH+ measured in the cold
neutral medium.Comment: accepted in Ap
Efferent Pathways in Sodium Overload-Induced Renal Vasodilation in Rats
Hypernatremia stimulates the secretion of oxytocin (OT), but the physiological role of OT remains unclear. the present study sought to determine the involvement of OT and renal nerves in the renal responses to an intravenous infusion of hypertonic saline. Male Wistar rats (280-350 g) were anesthetized with sodium thiopental (40 mg. kg(-1), i.v.). A bladder cannula was implanted for collection of urine. Animals were also instrumented for measurement of mean arterial pressure (MAP) and renal blood flow (RBF). Renal vascular conductance (RVC) was calculated as the ratio of RBF by MAP. in anesthetized rats (n = 6), OT infusion (0.03 mu g . kg(-1), i.v.) induced renal vasodilation. Consistent with this result, ex vivo experiments demonstrated that OT caused renal artery relaxation. Blockade of OT receptors (OXTR) reduced these responses to OT, indicating a direct effect of this peptide on OXTR on this artery. Hypertonic saline (3 M NaCl, 1.8 ml . kg(-1) b.wt., i.v.) was infused over 60 s. in sham rats (n = 6), hypertonic saline induced renal vasodilation. the OXTR antagonist (AT; atosiban, 40 mu g . kg(-1) . h(-1), i.v.; n = 7) and renal denervation (RX) reduced the renal vasodilation induced by hypernatremia. the combination of atosiban and renal denervation (RX+AT; n = 7) completely abolished the renal vasodilation induced by sodium overload. Intact rats excreted 51% of the injected sodium within 90 min. Natriuresis was slightly blunted by atosiban and renal denervation (42% and 39% of load, respectively), whereas atosiban with renal denervation reduced sodium excretion to 16% of the load. These results suggest that OT and renal nerves are involved in renal vasodilation and natriuresis induced by acute plasma hypernatremia.Fundacao de Amparo a Pesquisa do Estado de Goias (FAPEG)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Univ Fed Goias, Ctr Neurosci & Cardiovasc Physiol, Inst Biol Sci, Dept Physiol Sci, Goiania, Go, BrazilUniv Fed Uberlandia, Fac Phys Educ, Inst Biol Sci, BR-38400 Uberlandia, MG, BrazilUniversidade Federal de São Paulo, Dept Physiol, São Paulo, BrazilUniv Fed Goias, Inst Biol Sci, Mol Biol Lab, Goiania, Go, BrazilUniv Fed Goias, Inst Biol Sci, Dept Biochem & Mol Biol, Goiania, Go, BrazilUniversidade Federal de São Paulo, Dept Physiol, São Paulo, BrazilFundacao de Amparo a Pesquisa do Estado de Goias (FAPEG): 2012/0055431086Fundacao de Amparo a Pesquisa do Estado de Goias (FAPEG): 2009/10267000352CNPq: 477832/2010-5CNPq: 483411/2012-4Web of Scienc
Outcomes of Trypanosoma cruzi and Trypanosoma evansi infections on health of Southern coati (Nasua nasua), crab-eating fox (Cerdocyon thous), and ocelot (Leopardus pardalis) in the Brazilian Pantanal.
The occurrence of Trypanosoma spp. in wild carnivore populations has been intensively investigated during the last decades. However, the impact of these parasites on the health of free-living infected animals has been largely neglected. The Pantanal biome is the world's largest seasonal wetland, harboring a great diversity of species and habitats. This includes 174 species of mammals, of which 20 belong to the order Carnivora. The present study aimed to investigate the effect of Trypanosoma evansi and Trypanosoma cruzi infections and coinfections on the health of the most abundant carnivores in the Pantanal: coati (Nasua nasua), crab-eating fox (Cerdocyon thous), and ocelot (Leopardus pardalis). We captured 39 coatis, 48 crab-eating foxes, and 19 ocelots. Diagnostic tests showed T. cruzi infection in 7 crab-eating foxes and 5 coatis. Additionally, 7 crab-eating foxes, 10 coatis, and 12 ocelots were positive for T. evansi. We observed coinfections in 9 crab-eating foxes, 8 coatis, and 2 ocelots. This is the first report of T. evansi and T. cruzi infection on the health of free-living ocelots and crab-eating foxes. We showed that single T. evansi or T. cruzi infection, as well as coinfection, caused some degree of anemia in all animals, as well as an indirect negative effect on body condition in coatis and crab-eating foxes via anemia indicators and immune investment, respectively. Furthermore, the vigorous immune investment observed in sampled coatis, crab-eating foxes and ocelots infected by T. evansi, T. cruzi and coinfected can be highly harmful to their health. Overall, our results indicate that single and combined infection with T. evansi and T. cruzi represent a severe risk to the health of wild carnivores in the Pantanal region
Abundances of Deuterium, Nitrogen, and Oxygen toward HZ 43A: Results from the FUSE Mission
We present an analysis of interstellar absorption along the line of sight to
the nearby white dwarf star HZ43A. The distance to this star is 68+/-13 pc, and
the line of sight extends toward the north Galactic pole. Column densities of
OI, NI, and NII were derived from spectra obtained by the Far Ultraviolet
Spectroscopic Explorer (FUSE), the column density of DI was derived from a
combination of our FUSE spectra and an archival HST GHRS spectrum, and the
column density of HI was derived from a combination of the GHRS spectrum and
values derived from EUVE data obtained from the literature. We find the
following abundance ratios (with 2-sigma uncertainties): DI/HI = (1.66 +/-
0.28) x 10^-5, OI/HI = (3.63 +/- 0.84) x 10^-4, and NI/HI = (3.80 +/- 0.74) x
10^-5. The NII column density was slightly greater than that of NI, indicating
that ionization corrections are important when deriving nitrogen abundances.
Other interstellar species detected along the line of sight were CII, CIII,
OVI, SiII, ArI, MgII, and FeII; an upper limit was determined for NIII. No
elements other than HI were detected in the stellar photosphere.Comment: 52 pages, 12 figures. To be published in the May ApJS 200
Drought stress and tree size determine stem CO2 efflux in a tropical forest
CO2 efflux from stems (CO2_stem) accounts for a substantial fraction of tropical forest gross primary productivity, but the climate sensitivity of this flux remains poorly understood. We present a study of tropical forest CO2_stem from 215 trees across wet and dry seasons, at the world's longest running tropical forest drought experiment site. We show a 27% increase in wet season CO2_stem in the droughted forest relative to a control forest. This was driven by increasing CO2_stem in trees 10–40 cm diameter. Furthermore, we show that drought increases the proportion of maintenance to growth respiration in trees > 20 cm diameter, including large increases in maintenance respiration in the largest droughted trees, > 40 cm diameter. However, we found no clear taxonomic influence on CO2_stem and were unable to accurately predict how drought sensitivity altered ecosystem scale CO2_stem, due to substantial uncertainty introduced by contrasting methods previously employed to scale CO2_stem fluxes. Our findings indicate that under future scenarios of elevated drought, increases in CO2_stem may augment carbon losses, weakening or potentially reversing the tropical forest carbon sink. However, due to substantial uncertainties in scaling CO2_stem fluxes, stand‐scale future estimates of changes in stem CO2 emissions remain highly uncertain.This work is a product of a UK NERC independent fellowship grant NE/N014022/1 to L.R., a UK NERC grant NE/J011002/1 to P.M. and M.M., CNPQ grant 457914/2013-0/MCTI/CNPq/FNDCT/LBA/ESECAFLOR to A.C.L.d.C., an ARC
grant FT110100457 to P.M. It was previously supported by NERC NER/A/S/2002/00487, NERC GR3/11706, EU FP5-Carbonsink and EU FP7-Amazalert to P.M
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