HLA-G: expression in human keratinocytes in vitro and in human skin in vivo

Classical, polymorphic major histocompatibility complex class I molecules are expressed on most nucleated cells.They present peptides at the cell surface and, thus, enable the immune system to scan peptides for their antigenicity. The function of the other, nonclassical class I molecules in man is controversial. HLA-G which has been shown by transfection experiments to be expressed at the cell surface, is only transcribed in placental tissue and in the fetal eye.Therefore, a role of HLA-G in the control of rejection of the allogeneic fetus has been discussed. We found that HLA-G expression is induced in keratinocytes by culture in vitro. Three different alternative splicing products of HLA-G can be detected: a full length transcript, an mRNA lacking exon 3 and a transcript devoid of exon 3 and 4. Reverse transcription followed by polymerase chain reaction also revealed the presence of HLA-G mRNA in vivo in biopsies of either diseased or healthy skin

Potential for Acid Snowmelt in the Wasatch Mountains

Snowmelt collected from snow cores taken from the 1982 spring snowpack in the Wasatch Mountains of northern Utah lacked mineral acidity and retained enough buffering capacity in the form of calcium and magnesium bicarbonates to titrate additional inputs of strong acid equivalent to the amount apparently already neutralized. While acid anion concentrations were higher than those found in pristine areas, they were much lower than those reported for winter precipitation in other western areas experiencing acidification of precipitation. Snowmelt pH ranged from 5.62 to 6.88 (mean = 6.17), and sulfate was relatively more important than nitrate, showing an average equivalent ratio of 3.1:1. Patterns of pH indicated decreasing pH with distance from sources of soil-derived buffering capacity in the semiarid valleys to the east. Although acid anion concentration patterns failed to point to pollution sources along the Wasatch Front, chloride concentration patterns indicated that the Salt Lake Valley airshed influenced snow chemistry in the mountains. Snowmelt studies carried on in the laboratory and at a field site in Logan Canyon indicated that, for the alkaline snow typical of 1982, the first melt fractions had a higher pH (less acidity) than did the bulk snow. The opposite situation is typically found for acid snow. Although no acidity was present, snow pH increased by 13 percent as a result of contact with organic litter on the soil surface of a 22 m, 32 percent slope. The pH increased even more rapidly in a nearby intermittent stream 9to 7.78 at the edge of the snowpack). Difficulties in interpreting the data from the snow cores in this study include the effects of an unusually wet winter, uncharacteristically low levels of industrial activity due to economic factors, uncertainty about the relative amounts of acidity and buffering capacity reaching the sensitive Uintah Mountain watersheds to the east, and failure to distinguish between soil and acid derived sulfates. Analysis of these difficulties suggests taht offsetting factors would tend to cancel effects of precipitation amount during wet-to-normal winters. the remaining factors require additional research

Impacts of Western Coal, Oil Shale, and Tar Sands Development on Aquatic Environmental Quality: A Technical Information Matrix; Volume 1 Introduction and Instructions

Introduction: The Upper Colorado River Basin contains vast deposits of coal, oil shale, and tar sands, which could undergo extensive development should oil prices rise or an international situation restrict oil imports. Naturally, the prospect of development of these alternative fossil fuels resources has led to concern over how extraction and conversion activities will impact environmental quality. A thorough understanding of the nature and magnitude of the resulting envionemental impacts is a necessary prerequisite, if the costs and risks of such activites are to be weighed against the economic benefits. When we set out to evaluated these costs and risks, it soon became obvious that the voluminous literature in this area is difficult to access, often repetitive, and not well integrated into state-of-the-art reviews. This led us to realize the need to categorize and collate the results of such energy-related impact research in a way that would go beyond the compilation of a bibliography, or even keyworking relevant citations. The form of presentation that we eventually selected was the technical information matrix presented in this report. This matrix consists of information on the impacts of coal mining and conversion, oil shale mining and retoring, and tar sands development on four aspects of aquatic environmental quality: surface water and groundwater chemsitry, aquatic ecology, and aquifer modification. The report consists of three parts. This introductory volume contains instruction for use of the technical information matrix, a glossary, and sources of data on energy development and environmental impacts. Two additional looseleaf volumes contain the coal (II), and oil sahel and tar sands matrices (III), respectively, along with the corresponding matrix references and a bibliography of general (summary or overview) references. Each matrix volume also includes a list of symbols and abbreviations used in the matrix. Qualitatively, information on the three categories of fossil fuel development differs principally in amount, type, and geographical specificity. Coal extraction is a well-studied process in the East, where acid mine drainage and metal toxicity are well documented. In the West, surface mining of vast arid and semiarid tracts, as well as generally more alkaline mine drainage, has been less thoroughly studied. Nonetheless, commercial scale operations have been in place for a sufficiently long period, even in the West, to ahve produced a reasonably large data base. Coal conversion processes, although new, have also reached the commercial scale, and information is becoming relatively abundant. Conversely, environmental information is not generally availabel for the Scottish and Russian oil shale industries, or for the primitive industry in the Colorado Basin earlier in the century, and the present day oil shale industry in the west is insufficiently developed to have produced commerical scale case studies. Most information at present comes from pilot or semi-works facilities, and the impacts of a full-scale development over a 20-30 year project life are difficult to predict. Although Alberta, Canada, has a well developed tar sands industry, site specific information on tar sands development in the Colorado Basin is lacking. There are several areas of ommission in the coverage of sources of fossil fuel impact on aquatic environmental quality. Petroleum drilling, whose principal impacts in the Colorado Basin are related to interconnection of saline with good quality aquifers, creation of saline surface springs during exploration and illegal brine disposal practices has been omitted. Also, we have not pursued the effects of acid (e.g., Sox) base (e.g., NH3) or volatile metal (e.g., Hg) emissions to the atmosphere and their subsequent effects on downwind ecosystems when they are returned by precipitation or dry deposition. We have generally omitted the toxicological literature relating to occupational exposure (e.g., skin painting tests, etc.), as well as the impacts of water withdrawals on fish habitat through reduction of natural instream flows. In the latter cases such impacts require site specific consideration of hydrology and channel morphology. The more than 1300 citations in these matrices were gathered from a wide variety of refereed journals, symposium proceedings, government documents, abstracting services, and personal communications with researchers. The papers cited emphasize the period 1970-1981. Greatest emphasis was placed on the more recent literature, but late 1981 papers are probably underrepresented. There is also little doubt that we have failed to include some valuable material found in project reports, oral presentations, masters these, disserations, and similar sources. Certainly some citations were not optimally summarized or categorized, particularly when it was necessary to work from an abstract or summary. Hopefully, such exclusions or poor representations will not result in loss of excessive information or unduly mislead the users. We plan to update the matrix periodically, supplementing new information found with the searching techniques developed thus far and especially with information supplied by users. Updates will be in the form of looseleaf pages to be added to or substituted in Volumes I and II, and will be published as frequently as deemed necessary to cover developments in the subject areas. We would very much appreciate receiving copies (or summaries) of pertinent reports from the users of this matrix, together with corrections or improvements in the content or categorization of material presently in the matrix. There should be sent to: F.J. Post (coal) or Jay Messer (oil shale and tar sands) Utah Water Research Laboratory UMC 82 Utah State University Logan, UT 84322 They will be gratefully included in the next update

Crossovers from parity conserving to directed percolation universality

The crossover behavior of various models exhibiting phase transition to absorbing phase with parity conserving class has been investigated by numerical simulations and cluster mean-field method. In case of models exhibiting Z_2 symmetric absorbing phases (the NEKIMCA and Grassberger's A stochastic cellular automaton) the introduction of an external symmetry breaking field causes a crossover to kink parity conserving models characterized by dynamical scaling of the directed percolation (DP) and the crossover exponent: 1/\phi ~ 0.53(2). In case an even offspringed branching and annihilating random walk model (dual to NEKIMCA) the introduction of spontaneous particle decay destroys the parity conservation and results in a crossover to the DP class characterized by the crossover exponent: 1/\phi\simeq 0.205(5). The two different kinds of crossover operators can't be mapped onto each other and the resulting models show a diversity within the DP universality class in one dimension. These 'sub-classes' differ in cluster scaling exponents.Comment: 6 pages, 6 figures, accepted version in PR

A Multivariate Water Quality Index for Use in Management of a Wildland Watershed

Executive Summary: Summary: Multivariate statistical techniques were used to define a method for establishing a water quality index (WQI) for use in protecting the stream environment in a high mountain watershed. The purpose of the WQI was to aggregate water quality parameters in such a way that the effects of low level increments in mining, grazing, logging and other activities could be related to a change in the value of a single entity, aquatic environmental aquality, in a linear programming (LP) management model. Several data aggregation methods were explored, using water quality data collected over 5 years (1975-1979) by the USDA Forest Service in the upper Blackfoot River watershed in southeastern Idaho. The WQIs thus generated were compared with indices of benthic invertebrate community composition as determined from samples collected late in the summer of 1981. Community composition indices were based on emergent community properties (biomass and diversity) and on taxonomic composition as revealed by principal componenets analysis. Significant results of the study include the following: 1. Existing determinisitic general purpose WQIs (such as the National Sanitation Foundation Index) proved useless for guidance in protecting water quality in these high mountain watersheds, because stream water quality often remains excellent by drinking water standards, even though subtle changes in water quality parameters may significantly affect instream habitat. 2. An increasing scale, multivariate statistical WQI was created for the study area using 5-year May-October averages of ten water quality variables in eight streams. Removal of some streams from the data set, as well as aggregating or replacing some variables, did not significantly alter the rank order of the stream WQI values. 3. Changes in the calculation time step to 5-year bimonthly (May-June, July-August, September-October) or monthly averages, or to annual averages for four water years, provided little additional information, and resulting in decreasing sensitivity to changes in water quality variables because of larger standard deviations in the data sets. 4. The WQI was composed of four principal components that were easily interpretable as common factors (e.g., nutrient sources, suspended sediment sources, groundwater, and discharge) that affected groups of variables. These principal components, or subindices, were positively correlated with the presence of certain benthic invertebrate taxa or groups of taxa. 5. Cluster analysis was useful in reducing the dimensionality of water quality data and in revealing relationships among invertebrate communities (Q-type analysis). However, R-type cluster analysis of the study streams showed no similar groups of streams based on water quality variables. 6. The WQI was highly negatively correlated (r^2=0.93) with benthic invertebrate standing stock biomass, a relationship described by a decreasing power function. There was no apparent relationship between benthic invertebrate diversity and the WQI values. 7. The WQI-biomass relationship may be useful in setting a constraint value on the WQI in the LP model. Additional data and information from more sites should be collected and analyzed, however, to stengthen the confidence in the correlation, and to establish causality between the variables contributing strongly to the WQI and community biomass. 8. The multivariate WQI was found to be heavily influenced by the relative standard deviations of the variables used to form the index. Inclusion of only similar (pristine) streams in a baseline data set will result in a lower standard deviation for each variable. The result is higher sensitiviely to a given polluting factor than will be found in a mixed group of streams in which some are already impacted by anthropogenic activities. 9. High standard deviations for individual variables may mask relationships between environmentally significant parameters and biological communities. 10. Multivariate WQI indexing provides valuable insights into the relationship between water quality and biological community composition, even if appliaction of the WQIs in predictive settings is premature or ultimately proves to be unacceptable. Suggestions for Further Research: 1. Collect additional invertebrate data at other seasons and on Upper Angus and Mabie Creeks in order to reinforce or refine the relationships reported here. 2. Collect more detailed habitat data in order to elucidate the relative importance of water quality and physical habitat in controlling benthic community composition. Artificaial substrates may be useful in reducing physical habitat dissimilarity in order to focus on water quality effects. 3. Update the WQI using 1980-1982 data from the Forest Service and look for recent trends that would reinforce or alter the conclusions based on the older data. 4. Examine the use of standardized extreme values, rather than standardized means, to create a WQI. 5. Employ cannonical correlation as a means of further elucidating water quality-physical substrate-benthic community relationships. 6. Monitor changes in the WQI and benthic invertebrate community in one of the study streams in response to changing management practices (e.g., erosion control or additional phosphate mining). 7. Investigate the effects of a proposed change in management practice on a WQI using Monte-Carlo analysis to account for simultaneous changes in many variables. 8. Investigate the response of the invertebrates in principal components 1 and 4 to nutrients and suspended sediments in controlled (artificial) ecosystems to test their suitability as water quality indicators in the study area

Measurement of the two-photon absorption cross-section of liquid argon with a time projection chamber

This paper reports on laser-induced multiphoton ionization at 266 nm of liquid argon in a time projection chamber (LAr TPC) detector. The electron signal produced by the laser beam is a formidable tool for the calibration and monitoring of next-generation large-mass LAr TPCs. The detector that we designed and tested allowed us to measure the two-photon absorption cross-section of LAr with unprecedented accuracy and precision: sigma_ex=(1.24\pm 0.10stat \pm 0.30syst) 10^{-56} cm^4s{-1}.Comment: 15 pages, 9 figure

Semi-Hard Scattering Unraveled from Collective Dynamics by Two-Pion Azimuthal Correlations in 158 A GeV/c Pb + Au Collisions

Elliptic flow and two-particle azimuthal correlations of charged hadrons and high-$p_T$ pions ($p_T>$ 1 GeV/$c$) have been measured close to mid-rapidity in 158A GeV/$c$ Pb+Au collisions by the CERES experiment. Elliptic flow ($v_2$) rises linearly with $p_T$ to a value of about 10% at 2 GeV/$c$. Beyond $p_T\approx$ 1.5 GeV/$c$, the slope decreases considerably, possibly indicating a saturation of $v_2$ at high $p_T$. Two-pion azimuthal anisotropies for $p_T>$ 1.2 GeV/$c$ exceed the elliptic flow values by about 60% in mid-central collisions. These non-flow contributions are attributed to near-side and back-to-back jet-like correlations, the latter exhibiting centrality dependent broadening.Comment: Submitted to Phys. Rev. Letters, 4 pages, 5 figure

Recent results from Pb-Au collisions at 158 GeV/c per nucleon obtained with the CERES spectrometer

During the 1996 lead run time, CERES has accumulated 42 million events, corresponding to a factor of 5 more statistics than in 1995 and 2.5 million events of a special photon-run. We report on the results of the low-mass e$^+$e$^-$-pair analysis. Since the most critical item is the poor signal-to-background ratio we also discuss the understanding of this background, in absolute terms, with the help of a detailed Monte Carlo simulation. We show preliminary results of the photon analysis and summarize the results of the hadron analysis preliminarily reported on already at QM'97Comment: 10 pages, 9 figures, Proceedings of the XIV Int. Conf. on Nucleus-Nucleus Collisions,Quark Matter 99, Torino, Italy, May 10 - 15, 199

Ocular Blood Flow Measured Noninvasively in Zero Gravity

In spaceflight or a reduced-gravity environment, bodily fluids shift to the upper extremities of the body. The pressure inside the eye, or intraocular pressure, changes significantly. A significant number of astronauts report changes in visual acuity during orbital flight. To date this remains of unknown etiology. Could choroidal engorgement be the primary mechanism and a change in the curvature or shape of the cornea or lens be the secondary mechanism for this change in visual acuity? Perfused blood flow in the dense meshwork of capillaries of the choroidal tissue (see the preceding illustration) provides necessary nutrients to the outer layers of the retina (photoreceptors) to keep it healthy and maintain good vision. Unlike the vascular system, the choroid has no baroreceptors to autoregulate fluid shifts, so it can remain engorged, pushing the macula forward and causing a hyperopic (farsighted) shift of the eye. Experiments by researchers at the NASA Glenn Research Center could help answer this question and facilitate planning for long-duration missions. We are investigating the effects of zero gravity on the choroidal blood flow of volunteer subjects. This pilot project plans to determine if choroidal blood flow is autoregulated in a reduced-gravity environment

e+e--pair production in Pb-Au collisions at 158 GeV per nucleon

We present the combined results on electron-pair production in 158 GeV/n {Pb-Au} ($\sqrt{s}$= 17.2 GeV) collisions taken at the CERN SPS in 1995 and 1996, and give a detailed account of the data analysis. The enhancement over the reference of neutral meson decays amounts to a factor of 2.31$\pm0.19 (stat.)\pm0.55 (syst.)\pm0.69 (decays)$ for semi-central collisions (28% $\sigma/\sigma_{geo}$) when yields are integrated over $m>$ 200 MeV/$c^2$ in invariant mass. The measured yield, its stronger-than-linear scaling with $N_{ch}$, and the dominance of low pair $p_t$ strongly suggest an interpretation as {\it thermal radiation} from pion annihilation in the hadronic fireball. The shape of the excess centring at $m\approx$ 500 MeV/$c^2$, however, cannot be described without strong medium modifications of the $\rho$ meson. The results are put into perspective by comparison to predictions from Brown-Rho scaling governed by chiral symmetry restoration, and from the spectral-function many-body treatment in which the approach to the phase boundary is less explicit.Comment: 39 pages, 40 figures, to appear in Eur.Phys.J.C. (2005