Latest CMS Heavy-Ion Results on Jets

Jet studies provide an experimental method to explore the features of energy loss in the strongly interacting quark-gluon plasma. Recent jet results from 2.76 TeV PbPb and pp collisions measured with the CMS detector are presented. Jets in the most head-on (central) PbPb collisions are quenched in comparison to pp, and the jets fragment in different ways in the two systems. Measurements from pPb collisions at 5.02 TeV show that the jet and charged particle suppression seen in central PbPb measurements are not due to initial state nuclear effects.Comment: 6 pages, 4 figure

System size, energy and pseudorapidity dependence of directed and elliptic flow at RHIC

PHOBOS measurements of elliptic flow are presented as a function of pseudorapidity, centrality, transverse momentum, energy and nuclear species. The elliptic flow in Cu-Cu is surprisingly large, particularly for the most central events. After scaling out the geometry through the use of an alternative form of eccentricity, called the participant eccentricity, which accounts for nucleon position fluctuations in the colliding nuclei, the relative magnitude of the elliptic flow in the Cu-Cu system is qualitatively similar to that measured in the Au-Au system.Comment: Presented at the 18th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions in Budapest, Hungary, Aug. 4-9, 200

Inclusive jet and charged hadron nuclear modification factors in PbPb collisions at 2.76 TeV with CMS

AbstractMeasurements are reported for charged hadron and inclusive jet transverse momentum (pT) spectra in pp and PbPb collisions at a nucleon–nucleon center-of-mass energy of 2.76 TeV with the CMS detector. These measurements make use of the high-statistics jet-triggered data recorded in 2011, including the total available PbPb luminosity of 150μb−1. Charged particles are reconstructed using an iterative algorithm and spurious high-pT tracks are suppressed by requiring appropriate energy deposits in the calorimeter system. Jets are reconstructed with the anti-kT algorithm, using combined information from tracking and calorimetry. The charged particle pT distributions are measured in the pseudorapidity range of |η|<1, and pT up to 100 GeV/c. The jet pT distributions are measured in the pseudorapidity range of |η|<2, and pT from 100 to 300 GeV/c. The nuclear modification factors, RAA, for charged hadrons and jets are presented as a function of pT and collision centrality. In the range pT=5–10 GeV/c the charged hadron production in PbPb collisions is suppressed by up to a factor of seven, compared to the pp yield scaled by the number of incoherent nucleon–nucleon collisions. The charged hadron RAA increases at higher pT and approaches a value of approximately 0.5 in the range pT=40–100 GeV/c for the most central collisions

IMPACTS FROM DITCHING SALT MARSHES IN THE MID-ATLANTIC AND NORTHEASTERN UNITED STATES

Tidal inundation extent and duration, and water drainage and retention by marsh peat – marsh hydrology – determine most physical and ecological characteristics of salt marsh systems. Ditching, installed across nearly all marshes on the US East Coast by 1940 to control mosquitoes, alters marsh hydrology. Two linchpin papers are used here as springboards to review the literature that describes the resulting effects, which clearly include reduced water table height for most marshes and changes in avian populations. Effects on invertebrate populations, including mosquitoes, are generally less, although to a smaller degree than is sometimes reported. Impacts on nekton are not clear, although probably negative. Tidal range and the degree of tide asymmetry appear to have greater effects on inter-marsh variations in effects from ditching than has generally been appreciated or studied. Overall, although changed patterns of nutrient releases and promotion of Phragmites australis invasions are important ecological effects extending beyond individual sites, and salt marsh aesthetics are marred, ditching impacts are less than certain other anthropogenic alterations of coastal processes that affect salt marshes and estuarine ecology to a much greater extent

A Classification Methodology for Landfill Leachates

A characterization scheme based on landfill leachate chemical signatures could support studies of leachate evolution over time, liner performance, and help confirm or disprove potential leachate contamination of groundwater. Wide variations in single constituents across time, sites, and site practices, and inconsistencies related to common bivariate measures suggest a robust, multivariate analysis could be useful. A variant Stiff diagram approach (a subjective analytical comparison of soluble salts) has been developed, and supports graphical depictions of multiple samples. The hypothesis is that leachates with similar chemistry form clusters, and this was tested using a data set of 652 samples from 26 distinct liner systems collected from a Long Island (New York, USA) landfill over more than 20 years. Most (75%) of diagrams were classified into three general leachate groupings that associated with the kinds of wastes received in the particular landfill module (90% if early leachate results are not considered)

Estimates of Worst Case Baseline West Nile Virus Disease Effects in a Suburban New York County

Serosurveys conducted where West Nile Virus (WNV) caused health impacts were used to construct a model of potential worst case health impacts in a suburban setting. This model addressed two common public perceptions regarding mosquito control activities and WNV disease: it is not a disease of major consequence, and exposed populations quickly become immune. Comparisons to blood bank infection and serious disease incidence data were similar to some of the serosurvey model results. Accounting for theoretical increasing immunity, even over a 20-year horizon, did not substantially reduce the potential impacts. The model results were approximately an order of magnitude greater than those actually experienced in Suffolk County, New York; differences in mosquito populations and/or the degree of mosquito control between Suffolk County and serosurvey sites seem to be the cause of the differences

The long and short of verb alternations in Mauritian Creole and Bantu languages

AbstractMauritian Creole displays an alternation between a short and a long form of the verb, which is reminiscent of the conjoint–disjoint alternation found in some eastern Bantu languages. Based on comparison with other French-based creoles and socio-historical evidence, we conclude that the Bantu substrate must have had an impact on the grammatical system of Mauritian Creole. We compare the synchronic properties of the alternations in Mauritian Creole and the most likely substrate Bantu languages of northern Mozambique and examine two possible scenarios for the influence of Bantu on the Mauritian verbal alternation, concluding that probably only the (syntactic) basics of the Bantu alternation motivated the persistence of the alternation in Mauritian Creole.This is the author accepted manuscript. The final version is available from De Gruyter via http://dx.doi.org/10.1515/flin-2015-000

A Review of the Hyporheic Zone, Stream Restoration, and Means to Enhance Denitrification

The hyporheic zone is the subsurface area below and adjacent to a stream where groundwater mixes with stream water, through vertical, lateral, and longitudinal flows. The hyporheic zone connects the stream to uplands and other terrestrial environments. It is a zone of distinct faunal communities, high biological diversity and ecological complexity, and is the site of chemical processing and transformations of ground- and stream waters. The hyporheic zone is important to the overall ecosystem ecology of the stream, and it can influence stream water chemistry. Flows, reactions, and biota in the hyporheic zone are heterogeneous and patchy, making it difficult to clearly describe the ecotone in a straightforward, general way. Nitrogen processing, especially denitrification, appears to be widespread in the hyporheic zone. The hyporheic zone, as with most aquatic systems, is often impacted by human activities. Stream restorations rarely consider potential effects on the hyporheic zone, but careful project choices can enhance the condition of the hyporheic zone, and so increase uptake of nitrogen by stream-associated environments as partial mitigation of continuing and increasing releases of reactive nitrogen, potentially reaping short-term benefits to estuarine environments that might not be as quickly realized from source control measures

COST EFFECTIVENESS OF RECYCLING: A SYSTEMS MODEL

Financial analytical models of waste management systems have often found that recycling costs exceed direct benefits, and in order to economically justify recycling activities, externalities such as household expenses or environmental impacts must be invoked. Certain more empirically based studies have also found that recycling is more expensive than disposal. Other work, both through models and surveys, have found differently. Here we present an empirical systems model, largely drawn from a suburban Long Island municipality. The model accounts for changes in distribution of effort as recycling tonnages displace disposal tonnages, and the seven different cases examined all show that curbside collection programs that manage up to between 31% and 37% of the waste stream should result in overall system savings. These savings accrue partially because of assumed cost differences in tip fees for recyclables and disposed wastes, and also because recycling can result in a more efficient, cost-effective collection program. These results imply that increases in recycling are justifiable due to cost-savings alone, not on more difficult to measure factors that may not impact program budgets