3,582 research outputs found
RV POSEIDON Cruise Report POS420 COWACSS Biological observation and sampling of cold-water corals to investigate impacts on climate change
Trondheim – (Kristiansund) – Kiel
08. – (25.) – 30.09.201
Seleção para la tolerância ao encharcamento na variedade de milho CMS54 - Saracura.
A variedade de milho CMS 54 e um composto sintetizado no CNPMS/EMBRAPA em 1986, a partir de mistura balanceada de sementes de 36 populacoes de milho. Esta variedade vem sendo selecionada para tolerancia ao encharcamento do solo, sendo que em 1996 foi obtido a nono ciclo de selecao massal. Em 1996 foram conduzidos dois experimentos para avaliar o ganho de selecao tanto sob encharcamento, quanto em condicao nao encharcada (normal). Os 9 primeiros ciclos de selecao foram avaliados sob encharcamento num delineamento em blocos ao acaso com 7 repeticoes. Do ciclo 1 para o ciclo 9 e o peso de espigas aumentou em 25% com um ganho medio estimado por ciclo (coeficiente de regressao) de 3,2% (p<0.01), equivalente a 164 kg/espigas/ha/ciclo. Em um segundo ensaio, os 8 primeiros ciclos de selecao foram avaliados em condicao nao encharcada. Houve diferenca significativa (p<0.05) para peso de espigas entre ciclo, com um aumento de 14% do ciclo 1 para o ciclo 8. Entretanto os ganhos por ciclo quando avaliados sob condicao nao encharcado nao foram lineares ja que o coeficiente de regressao de 1.3% nao foi significativo. No ano agricola 96/97 a variedade CMS 54-Saracura foi distribuido para teste a cerca de 2000 produtores em areas sujeitas a encharcamento no Brasil. Sua producao comercial deve iniciar-se no verao 97/98
Cold-water corals in the Bay of Biscay - occurrences and distribution in space and time (TransBiscay) - Cruise No. M84/5, May 31 - June 21, 2011, Vigo (Spain) - Brest (France)
The scientific objectives of METEOR cruise M84/5 focused on the measurement
and analysis of the environmental controls of modern and fossil cold-water coral growth
along a transect in the Bay of Biscay. In four working areas we successfully deployed lander
systems and CTD/Ro’s to document the physical and hydrochemical characteristics of bottom
water masses and the water column in general. These are used to shed light on potential
linkages to modern cold-water coral growth and distribution. These investigations were
flanked by plankton tows in surface waters. The base for all investigations was a thorough
hydroacoustic survey to characterize potential cold-water coral bearing areas with living
colonies. Based on these maps we deployed all video-guided gear such as the OFOS-video
sled, the TV grab, and the lander systems. Benthic assemblages and sedimentary structures
have been documented and sampled with the OFOS and a box corer. Simultaneously, genetic
samples of the living coral material were taken for additional studies. Furthermore, we have
taken gravity cores to investigate the paleoceanographic conditions as well as the timing of
cold-water coral colonization in the Bay of Biscay. Along with the coring efforts, a detailed
sampling and study of porewater properties was performed. An additional aim of this cruise
was to investigate the influence of boundary exchange processes on the Neodymium isotopy
in bottom waters along the pathway of the Mediterranean Outflow water (MOW) by taking
multiple samples with the CTD/Ro.
The new data and samples of this METEOR cruise will provide the framework to
investigate the timing of cold-water coral colonization in the Bay of Biscay, as well as its
interplay with the ambient hydrography and geochemistry. This successful cruise has
provided the basis to investigate the scientific aims of this expedition in great detail
Asymptotically Lifshitz wormholes and black holes for Lovelock gravity in vacuum
Static asymptotically Lifshitz wormholes and black holes in vacuum are shown
to exist for a class of Lovelock theories in d=2n+1>7 dimensions, selected by
requiring that all but one of their n maximally symmetric vacua are AdS of
radius l and degenerate. The wormhole geometry is regular everywhere and
connects two Lifshitz spacetimes with a nontrivial geometry at the boundary.
The dynamical exponent z is determined by the quotient of the curvature radii
of the maximally symmetric vacua according to n(z^2-1)+1=(l/L)^2, where L
corresponds to the curvature radius of the nondegenerate vacuum. Light signals
are able to connect both asymptotic regions in finite time, and the
gravitational field pulls towards a fixed surface located at some arbitrary
proper distance to the neck. The asymptotically Lifshitz black hole possesses
the same dynamical exponent and a fixed Hawking temperature given by T=z/(2^z
pi l). Further analytic solutions, including pure Lifshitz spacetimes with a
nontrivial geometry at the spacelike boundary, and wormholes that interpolate
between asymptotically Lifshitz spacetimes with different dynamical exponents
are also found.Comment: 19 pages, 1 figur
Giant Magnons
Studies of super Yang Mills operators with large R-charge have
shown that, in the planar limit, the problem of computing their dimensions can
be viewed as a certain spin chain. These spin chains have fundamental
``magnon'' excitations which obey a dispersion relation that is periodic in the
momentum of the magnons. This result for the dispersion relation was also shown
to hold at arbitrary 't Hooft coupling. Here we identify these magnons on the
string theory side and we show how to reconcile a periodic dispersion relation
with the continuum worldsheet description. The crucial idea is that the
momentum is interpreted in the string theory side as a certain geometrical
angle. We use these results to compute the energy of a spinning string. We also
show that the symmetries that determine the dispersion relation and that
constrain the S-matrix are the same in the gauge theory and the string theory.
We compute the overall S-matrix at large 't Hooft coupling using the string
description and we find that it agrees with an earlier conjecture. We also find
an infinite number of two magnon bound states at strong coupling, while at weak
coupling this number is finite.Comment: 34 pages, 9 figures, latex v2: references adde
RNA-Peptide nanoplexes drug DNA damage pathways in high-grade serous ovarian tumors
DNA damaging chemotherapy is a cornerstone of current front‐line treatments for advanced ovarian cancer (OC). Despite the fact that a majority of these patients initially respond to therapy, most will relapse with chemo‐resistant disease; therefore, adjuvant treatments that synergize with DNA‐damaging chemotherapy could improve treatment outcomes and survival in patients with this deadly disease. Here, we report the development of a nanoscale peptide‐nucleic acid complex that facilitates tumor‐specific RNA interference therapy to chemosensitize advanced ovarian tumors to frontline platinum/taxane therapy. We found that the nanoplex‐mediated silencing of the protein kinase, MK2, profoundly sensitized mouse models of high‐grade serous OC to cytotoxic chemotherapy by blocking p38/MK2‐dependent cell cycle checkpoint maintenance. Combined RNAi therapy improved overall survival by 37% compared with platinum/taxane chemotherapy alone and decreased metastatic spread to the lungs without observable toxic side effects. These findings suggest (a) that peptide nanoplexes can serve as safe and effective delivery vectors for siRNA and (b) that combined inhibition of MK2 could improve treatment outcomes in patients currently receiving frontline chemotherapy for advanced OC.National Institutes of Health (U.S.) (Grant R01-ES015339)National Institute of Biomedical Imaging and Bioengineering (U.S.) (Grant 1F32EB017614)National Science Foundation (U.S.) (Grant GFRP 1122374)National Cancer Institute (U.S.) (Grant P30-CA14051)National Science Foundation (U.S.) (Grant DMR-0819762
Generalized cusp in AdS_4 x CP^3 and more one-loop results from semiclassical strings
We evaluate the exact one-loop partition function for fundamental strings
whose world-surface ends on a cusp at the boundary of AdS_4 and has a "jump" in
CP^3. This allows us to extract the stringy prediction for the ABJM generalized
cusp anomalous dimension Gamma_{cusp}^{ABJM} (phi,theta) up to NLO in
sigma-model perturbation theory. With a similar analysis, we present the exact
partition functions for folded closed string solutions moving in the AdS_3
parts of AdS_4 x CP^3 and AdS_3 x S^3 x S^3 x S^1 backgrounds. Results are
obtained applying to the string solutions relevant for the AdS_4/CFT_3 and
AdS_3/CFT_2 correspondence the tools previously developed for their AdS_5 x S^5
counterparts.Comment: 48 pages, 2 figures, version 3, corrected misprints in formulas 2.12,
B.86, C.33, added comment on verification of the light-like limi
Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV
A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay
channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7
TeV is presented. The data were collected at the LHC, with the CMS detector,
and correspond to an integrated luminosity of 4.6 inverse femtobarns. No
significant excess is observed above the background expectation, and upper
limits are set on the Higgs boson production cross section. The presence of the
standard model Higgs boson with a mass in the 270-440 GeV range is excluded at
95% confidence level.Comment: Submitted to JHE
Combined search for the quarks of a sequential fourth generation
Results are presented from a search for a fourth generation of quarks
produced singly or in pairs in a data set corresponding to an integrated
luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in
2011. A novel strategy has been developed for a combined search for quarks of
the up and down type in decay channels with at least one isolated muon or
electron. Limits on the mass of the fourth-generation quarks and the relevant
Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a
simple extension of the standard model with a sequential fourth generation of
fermions. The existence of mass-degenerate fourth-generation quarks with masses
below 685 GeV is excluded at 95% confidence level for minimal off-diagonal
mixing between the third- and the fourth-generation quarks. With a mass
difference of 25 GeV between the quark masses, the obtained limit on the masses
of the fourth-generation quarks shifts by about +/- 20 GeV. These results
significantly reduce the allowed parameter space for a fourth generation of
fermions.Comment: Replaced with published version. Added journal reference and DO
Molecular, microbiological and clinical characterization of Clostridium difficile isolates from tertiary care hospitals in Colombia
In Colombia, the epidemiology and circulating genotypes of Clostridium difficile have not yet been described. Therefore, we molecularly characterized clinical isolates of C.difficile from patients with suspicion of C.difficile infection (CDI) in three tertiary care hospitals. C.difficile was isolated from stool samples by culture, the presence of A/B toxins were detected by enzyme immunoassay, cytotoxicity was tested by cell culture and the antimicrobial susceptibility determined. After DNA extraction, tcdA, tcdB and binary toxin (CDTa/CDTb) genes were detected by PCR, and PCR-ribotyping performed. From a total of 913 stool samples collected during 2013–2014, 775 were included in the study. The frequency of A/B toxins-positive samples was 9.7% (75/775). A total of 143 isolates of C.difficile were recovered from culture, 110 (76.9%) produced cytotoxic effect in cell culture, 100 (69.9%) were tcdA+/tcdB+, 11 (7.7%) tcdA-/tcdB+, 32 (22.4%) tcdA-/tcdB- and 25 (17.5%) CDTa+/CDTb+. From 37 ribotypes identified, ribotypes 591 (20%), 106 (9%) and 002 (7.9%) were the most prevalent; only one isolate corresponded to ribotype 027, four to ribotype 078 and four were new ribotypes (794,795, 804,805). All isolates were susceptible to vancomycin and metronidazole, while 85% and 7.7% were resistant to clindamycin and moxifloxacin, respectively. By multivariate analysis, significant risk factors associated to CDI were, staying in orthopedic service, exposure to third-generation cephalosporins and staying in an ICU before CDI symptoms; moreover, steroids showed to be a protector factor. These results revealed new C. difficile ribotypes and a high diversity profile circulating in Colombia different from those reported in America and European countries
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