746 research outputs found
Comparison of DrugResponses in Vivoandin VitroinAirwaysof DogswithandwithoutAirwayHyperresponsiveness'
ABSTRACT muscle were 7.03 ±0.11 in BG dogs and 7.50 ±0.11 in greyhounds. A significant (P < .01) negative correlation was found between methacholine sensitivity in vivo and in vitro. Aerosol concentrations of histamine required to produce a 2-fold increase in pulmonary reaistance were 0. determined against a half-maximai methacholine contraction. Aerosol methacholine concentrations required to produce a 2-fold increase in pulmonary resistance were 0.07 ±0.02 (±S.E.) mg/mI in BG dogs and 0.67 ±0.26 mg/mI in greyhounds; pD2 values for methacholine-inducedcontraction ofcervical trachealis In the search for the defect underlying asthma, mechanical and biochemical properties of airway smooth muscle have been compared in unsensitized and antigen-sensitized animals of several species. Although differences in drug responses have been found (Souhrada, 1978; Antonissen et at., 1979; In contrast to most animal models of asthma, the BG mechanical responses to methacholine, histamine and isopro terenol in isolated trachealis muscle preparations of five BG and five unrelated greyhounds, which had been tested previ ously for sensitivity to methacholine and histamine aerosols in vivo. Methods Subjects. The studies were performed in five BG dogs and five unrelated greyhounds that were age matched (â€"2 years old) and housed under identical conditions in the animal quarters at Oregon Health Sciences University. BG dogs ranged from 18 to 23 kg and greyhounds from 27 to 37 kg. All animals had been selected especially for this study, and had not been tested previously as part of other ongoing studies. 21
Mid Infrared Polarisation of Ultraluminous Infrared Galaxies
The mid infrared polarisation properties of four Ultraluminous Infrared
Galaxies (ULIRGs) have been investigated by broad band filter observations with
the ISOCAM instrument on board the Infrared Space Observatory (ISO). The
wavelength region from 5 to 18 mic. was selected where the emission from the
putative torus peaks. We report detection of polarisation for all ULIRGs
studied. The fractional polarisation ranges from about 3% up to 8%. The highest
polarisation is recorded in Mrk231 which has a clear AGN signature, whereas the
lowest is for Arp220, which is generally thought to be powered predominantly by
star formation. We discuss the various mechanisms that could give rise to the
polarisation and conclude that the most likely interpretation is that it is due
to magnetically aligned elongated dust grains. This is the same mechanism
believed to be operating in a number of galactic sources. The position angle of
polarisation could give the projected magnetic field direction and therefore
constrain models for the formation of the tori.Comment: Accepted by A&A (Letter
Anti-Nirvana: crime, culture and instrumentalism in the age of insecurity
‘Anti-Nirvana’ explores the relationship between consumer culture, media and criminal motivations. It has appeared consistently on the list of the top-ten most-read articles in this award-winning international journal, and it mounts a serious neo-Freudian challenge to the predominant naturalistic notion of ‘resistance’ at the heart of liberal criminology and media studies. It is also cited in the Oxford Handbook of Criminology and other criminology texts as a persuasive argument in support of the theory that criminality amongst young people is strongly linked to the acquisitive values of consumerism and the images of possessive individualism that dominate mass media
Determination of Rare Earth Elements, Sc, Y, Zr, Ba, Hf and Th in Geological Samples by ICP-MS after Tm Addition and Alkaline Fusion
International audienceWe present a revised method for the determination of concentrations of rare earth (REE) and other trace elements (Y, Sc, Zr, Ba, Hf, Th) in geological samples. Our analytical procedure involves sample digestion using alkaline fusion (NaOH-Na2O2) after addition of a Tm spike, co-precipitation on iron hydroxides, and measurement by sector field-inductively coupled plasma-mass spectrometry (SF-ICP-MS). The procedure was tested successfully for various rock types (i.e., basalt, ultramafic rock, sediment, soil, granite), including rocks with low trace element abundances (sub ng g−1). Results obtained for a series of nine geological reference materials (BIR-1, BCR-2, UB-N, JP-1, AC-E, MA-N, MAG-1, GSMS-2, GSS-4) are in reasonable agreement with published working values
A tale of two capitalisms: preliminary spatial and historical comparisons of homicide rates in Western Europe and the USA
This article examines comparative homicide rates in the United States and Western Europe in an era of increasingly globalized neoliberal economics. The main finding of this preliminary analysis is that historical and spatial correlations between distinct forms of political economy and homicide rates are consistent enough to suggest that social democratic regimes are more successful at fostering the socio-cultural conditions necessary for reduced homicide rates. Thus Western Europe and all continents and nations should approach the importation of American neo-liberal economic policies with extreme caution. The article concludes by suggesting that the indirect but crucial causal connection between political economy and homicide rates, prematurely pushed into the background of criminological thought during the ‘cultural turn’, should be returned to the foreground
On the formation, ventilation, and erosion of mode waters in the North Atlantic and Southern Oceans
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94834/1/jgrc12564.pd
A multistate outbreak of Escherichia coli O157:H7 infections linked to alfalfa sprouts grown from contaminated seeds.
A multistate outbreak of Escherichia coli O157:H7 infections occurred in the United States in June and July 1997. Two concurrent outbreaks were investigated through independent case-control studies in Michigan and Virginia and by subtyping isolates with pulsed-field gel electrophoresis (PFGE). Isolates from 85 persons were indistinguishable by PFGE. Alfalfa sprouts were the only exposure associated with E. coli O157:H7 infection in both Michigan and Virginia. Seeds used for sprouting were traced back to one common lot harvested in Idaho. New subtyping tools such as PFGE used in this investigation are essential to link isolated infections to a single outbreak
Clustering of galaxies around radio quasars at 0.5 < z < 0.8
We have observed the galaxy environments around a sample of 21 radio-loud,
steep-spectrum quasars at 0.5<z<0.82, spanning several orders of magnitude in
radio luminosity. The observations also include background control fields used
to obtain the excess number of galaxies in each quasar field. The galaxy excess
was quantified using the spatial galaxy-quasar correlation amplitude, B_gq, and
an Abell-type measurement, N_0.5 (Hill & Lilly 1991). A few quasars are found
in relatively rich clusters, but on average, they seem to prefer galaxy groups
or clusters of approximately Abell class 0. We have combined our sample with
literature samples extending down to z=0.2 and covering the same range in radio
luminosity. By using Spearman statistic to disentangle redshift and luminosity
dependences, we detect a weak, but significant, positive correlation between
the richness of the quasar environment and the quasar's radio luminosity.
However, we do not find any epoch dependence in B_gq, as has previously been
reported for radio quasars and galaxies. We discuss the radio
luminosity-cluster richness link and possible explanations for the weak
correlation that is seen.Comment: 18 pages, 9 figures, submitted to MNRA
How good are Bayesian belief networks for environmental management? A test with data from an agricultural river catchment
1. The ecological health of rivers worldwide continues to decline despite increasing effort and investment in river science and management. Bayesian belief networks (BBNs) are increasingly being used as a mechanism for decision-making in river management because they provide a simple visual framework to explore different management scenarios for the multiple stressors that impact rivers. However, most applications of BBN modelling to resource management use expert knowledge and/or limited real data, and fail to accurately assess the ability of the model to make predictions. 2. We developed a BBN to model ecological condition in a New Zealand river using field/GIS data (from multiple rivers), rather than expert opinion, and assessed its predictive ability on an independent dataset. The developed BBN performed moderately better than a number of other modelling techniques (e.g., artificial neural networks, classification trees, random forest, logistic regression), although model construction was more time3consuming. Thus the predictive ability of BBNs is (in this case at least) on a par with other modelling methods but the approach is distinctly better for its ability to visually present the data linkages, issues and potential outcomes of management options in real time. 3. The BBN suggested management of habitat quality, su ch as riparian planting, along with the current management focus on limiting nutrient leaching from agricultural land may be most effective in improving ecological condition. 4. BBNs can be a powerful and accurate method of effectively portraying the multiple interacting drivers of environmental condition in an easily understood manner. However, most BBN applications fail to appropriately test the model fit prior to use. We believe this lack of testing may seriously undermine their long-term effectiveness in resource management, and recommend that BBNs should be used in conjunction with some measure of uncertainty about model predictions. We have demonstrated this for a BBN of ecological condition in a New Zealand river, shown that model fit is better than that for other modelling techniques, and that improving habitat would be equally effective to reducing nutrients to improve ecological condition
Ethylene receptor ETR2 controls trichome branching by regulating microtubule assembly in Arabidopsis thaliana
The single-celled trichome of Arabidopsis thaliana is a widely used model system for studying cell development. While the pathways that control the later stages of trichome development are well characterized, the early signalling events that co-ordinate these pathways are less well understood. Hormones such as gibberellic acid, salicylic acid, cytokinins, and ethylene are known to affect trichome initiation and development. To understand the role of the plant hormone ethylene in trichome development, an Arabidopsis loss-of-function ethylene receptor mutant, etr2-3, which has completely unbranched trichomes, is analysed in this study. It was hypothesized that ETR2 might affect the assembly of the microtubule cytoskeleton based on analysis of the cytoskeleton in developing trichomes, and exposures to paclitaxol and oryzalin, which respectively act either to stabilize or depolymerize the cytoskeleton. Through epistatic and gene expression analyses it is shown that ETR2 is positioned upstream of CHROMATIN ASSEMBLY FACTOR1 and TRYPTICHON and is independent of the GLABRA2 and GLABRA3 pathways. These results help extend understanding of the early events that control trichome development and identify a signalling pathway through which ethylene affects trichome branching
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