927 research outputs found
Radio and IR study of the massive star-forming region IRAS 16353-4636
Context. With the latest infrared surveys, the number of massive protostellar
candidates has increased significantly. New studies have posed additional
questions on important issues about the formation, evolution, and other
phenomena related to them. Complementary to infrared data, radio observations
are a good tool to study the nature of these objects, and to diagnose the
formation stage. Aims. Here we study the far-infrared source IRAS 16353-4636
with the aim of understanding its nature and origin. In particular, we search
for young stellar objects (YSOs), possible outflow structure, and the presence
of non-thermal emission. Methods. Using high-resolution, multi-wavelength radio
continuum data obtained with the Australia Telescope Compact Array, we image
IRAS 16353-4636 and its environment from 1.4 to 19.6 GHz, and derive the
distribution of the spectral index at maximum angular resolution. We also
present new JHKs photometry and spectroscopy data obtained at ESO NTT. 13 CO
and archival HI line data, and infrared databases (MSX, GLIMPSE, MIPSGal) are
also inspected. Results. The radio continuum emission associated with IRAS
16353-4636 was found to be extended (~10 arcsec), with a bow-shaped morphology
above 4.8 GHz, and a strong peak persistent at all frequencies. The NIR
photometry led us to identify ten near-IR sources and classify them according
to their color. We used the HI line data to derive the source distance, and
analyzed the kinematical information from the CO and NIR lines detected.
Conclusions. We have identified the source IRAS 16353-4636 as a new
protostellar cluster. In this cluster we recognized three distinct sources: a
low-mass YSO, a high-mass YSOs, and a mildly confined region of intense and
non-thermal radio emission. We propose the latter corresponds to the terminal
part of an outflow.Comment: To appear in A&A. 10 pages, 8 figure
Helmintofauna del aparato digestivo y respiratorio de aves acuĂĄticas (Anatidae: Anatinae) del humedal de Atlangatepec, Tlaxcala, MĂ©xico
The purpose of this investigation was to carry out the first inventory of helminths collected from waterfowl (n=52) of the family Anatidae. This work took place in wetland Atlangatepec, Tlaxcala. Helminths were collected from the digestive tract and the respiratory system of waterfowl donated by hunters. Collected parasites were processed using conventional fixation and staining techniques for the identification of helminth. Twenty-one taxa of helminth were identified as follow: seven trematodes (Cotylurus cornutus, Australapatemon burti, Zygocotyle lunata, Notocotylus seineti, Typhlocoelum sisowi, Echinostoma sp. and Echinoparyphium recurvatum), four cestodes (Hymenolepis sp, Cloacotaenia megalops, Choanotaenia infundibulum and Fimbriaria fasciolaris), eight nematodes (Amidostomum sp., Streptocara sp., Epomidiostomum uncinatum, Syphaciella sp., Capillaria sp., Tetrameres fissispina, Tetrameres sp. and Echinuria uncinata) and two Acanthocephala (Pseudocorynosoma constritum and Polimorphus sp.). It is relevant to highlight that this is the first report of Syphaciella sp. in waterfowl in Mexico.El objetivo de esta investigación fue realizar el primer inventario de helmintos recuperados a partir del tubo digestivo y del aparato respiratorio de 52 aves acuåticas de la familia Anatidae, procedentes del humedal de Atlangatepec, Tlaxcala, a partir del aparato digestivo y respiratorio, los cuales fueron donados por cazadores en la temporada de caza de noviembre 2012- febrero 2013 y noviembre 2013- febrero 2014. Los paråsitos encontrados se procesaron empleando técnicas convencionales para el examen helmintológico. Se identificaron 21 taxa de helmintos: siete trematodos (Cotylurus. cornutus, Australapatemon burti, Zygocotyle. lunata, Notocotylus. seineti, Typhlocoelum. sisowi, Echinostoma sp. y Echinoparyphium recurvatum.), cuatro cestodos (Hymenolepis sp., Cloacotaenia megalops, Choanotaenia infundibulum y Fimbriaria fasciolaris), ocho nematodos (Amidostomum sp., Streptocara sp., Epomidiostomum uncinatum, Syphaciella sp., Capillaria sp., Tetrameres. fissispina, Tetrameres sp. y Echinuria uncinata) y dos acantocéfalos (Pseudocorynosoma constritum y Polimorphus sp.), entre ellos destaca Syphaciella sp., ya que se registra por primera vez para México. También se registra por primera vez para México a los trematodos: Z. lunata y A. burti en A. crecca y A. strepera. En el caso de los cestodos a C. infundibulum en A. affinis
Discovery of non-climacteric and suppressed climacteric bud sport mutations originating from a climacteric Japanese plum cultivar (Prunus salicina Lindl.).
Japanese plums are classified as climacteric; however, some economically important cultivars selected in California produce very little ethylene and require long ripening both "on" and "off" the tree to reach eating-ripe firmness. To unravel the ripening behavior of different Japanese plum cultivars, ripening was examined in the absence (air) or in the presence of ethylene or propylene (an ethylene analog) following a treatment or not with 1-methylcyclopropene (1-MCP, an ethylene action inhibitor). Detailed physiological studies revealed for the first time three distinct ripening types in plum fruit: climacteric, suppressed-climacteric, and non-climacteric. Responding to exogenous ethylene or propylene, the slow-softening supressed-climacteric cultivars produced detectable amounts of ethylene, in contrast to the novel non-climacteric cultivar that produced no ethylene and softened extremely slowly. Genetic analysis using microsatellite markers produced identical DNA profiles for the climacteric cultivars "Santa Rosa" and "July Santa Rosa," the suppressed-climacteric cultivars "Late Santa Rosa," "Casselman," and "Roysum" and the novel non-climacteric "Sweet Miriam," as expected since historic records present most of these cultivars as bud-sport mutations derived initially from "Santa Rosa." This present study provides a novel fruit system to address the molecular basis of ripening and to develop markers that assist breeders in providing high-quality stone fruit cultivars that can remain "on-tree," increasing fruit flavor, saving harvesting costs, and potentially reducing the need for low-temperature storage during postharvest handling
Diversity for chemical composition in a collection of different varietal types of tree tomato (Solanum betaceum Cav.), an Andean exotic fruit
[EN] We evaluated 23 tree tomato (Solanum betaceum) accessions from five cultivar groups and one wild relative (Solanum cajanumense) for 26 composition traits. For all traits we found highly significant differences (P < 0.001) among the materials studied. The high diversity found within S. betaceum for composition traits was matched by a high diversity within each of the cultivar groups. We found that sucrose and citric acid were the most important soluble sugar and organic acid, respectively, in tree tomato. Fruit in the anthocyanin pigmented (purple) group had a carotenoid content similar to that in the yellow-orange cultivar groups. Total phenolic content was significantly correlated (r = 0.8607) with antioxidant activity. Analyses of mineral content showed that tree tomato is a good source of K, Mg, and Cu. Multivariate principal components analysis (PCA) confirmed that an important diversity exists within each cultivar group. The results we have obtained indicate that the high diversity found within the tree tomato could be exploited for selection and breeding for developing the tree tomato as a commercial crop. (C) 2014 Elsevier Ltd. All rights reserved.This work was partially financed by the Ecuadorian Secretaria Nacional de Educacion Superior, Ciencia, Tecnologia e Innovacion from Ecuador (SENESCYT).Acosta-Quezada, P.; RaigĂłn JimĂ©nez, MD.; RiofrĂo-Cuenca, T.; GarcĂa MartĂnez, MD.; Plazas Ăvila, MDLO.; Burneo, J.; Figueroa, JG.... (2015). Diversity for chemical composition in a collection of different varietal types of tree tomato (Solanum betaceum Cav.), an Andean exotic fruit. Food Chemistry. 169:327-335. doi:10.1016/j.foodchem.2014.07.152S32733516
Monsters, Laws of Nature, and Teleology in Late Scholastic Textbooks
In the period of emergence of early modern science, âmonstersâ or individuals with physical congenital anomalies were considered as rare events which required special explanations entailing assumptions about the laws of nature. This concern with monsters was shared by representatives of the new science and Late Scholastic authors of university textbooks. This paper will reconstruct the main theses of the treatment of monsters in Late Scholastic textbooks, by focusing on the question as to how their accounts conceived natureâs regularity and teleology. It shows that they developed a naturalistic teratology in which, in contrast to the naturalistic explanations usually offered by the new science, finality was at central stage. This general point does not impede our noticing that some authors were closer to the views emerging in the Scientific Revolution insofar as they conceived nature as relatively autonomous from God and gave a relevant place to efficient secondary causation. In this connection, this paper suggests that the concept of the laws of nature developed by the new science âas exception-less regularitiesâtransferred to natureâs regularity the âstrongâ character that Late Scholasticism attributed to finality and that the decline of the Late Scholastic view of finality played as an important concomitant factor permitting the transformation of the concept of laws of nature
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
Measurement of the t t-bar production cross section in the dilepton channel in pp collisions at sqrt(s) = 7 TeV
The t t-bar production cross section (sigma[t t-bar]) is measured in
proton-proton collisions at sqrt(s) = 7 TeV in data collected by the CMS
experiment, corresponding to an integrated luminosity of 2.3 inverse
femtobarns. The measurement is performed in events with two leptons (electrons
or muons) in the final state, at least two jets identified as jets originating
from b quarks, and the presence of an imbalance in transverse momentum. The
measured value of sigma[t t-bar] for a top-quark mass of 172.5 GeV is 161.9 +/-
2.5 (stat.) +5.1/-5.0 (syst.) +/- 3.6(lumi.) pb, consistent with the prediction
of the standard model.Comment: Replaced with published version. Included journal reference and DO
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
Quantum numbers of the state and orbital angular momentum in its decay
Angular correlations in decays, with , and , are used to measure
orbital angular momentum contributions and to determine the value of
the meson. The data correspond to an integrated luminosity of 3.0
fb of proton-proton collisions collected with the LHCb detector. This
determination, for the first time performed without assuming a value for the
orbital angular momentum, confirms the quantum numbers to be .
The is found to decay predominantly through S wave and an upper limit
of at C.L. is set on the fraction of D wave.Comment: 16 pages, 4 figure
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