Chemical Equilibration in Hadronic Collisions

We study chemical equilibration in out-of-equilibrium Quark-Gluon Plasma using the first principles method of QCD effective kinetic theory, accurate at weak coupling. In longitudinally expanding systems--relevant for relativistic nuclear collisions--we find that for realistic couplings chemical equilibration takes place after hydrodynamization, but well before local thermalization. We estimate that hadronic collisions with final state multiplicities ${dN_\text{ch}}/{d\eta}\gtrsim 10^2$ live long enough to reach approximate chemical equilibrium, which is consistent with the saturation of strangeness enhancement observed in proton-proton, proton-nucleus and nucleus-nucleus collisions.Comment: 7 pages, 3 figures, see also our companion paper arXiv:1811.03068, v2 small changes, published versio

Police Use of Firearms in West Virginia--An Empirical Study

In its study of crime and law enforcement in the United States, the President\u27s Commission on Law Enforcement and Administration of Justice found it surprising and alarming that few police departments provide their officers with careful instruction on the circumstances under which the use of a firearm is permissible. This failure on the part of police administrators leaves the uninformed patrolman, charged with the day to day duty of law enforcement, subject to civil and criminal liability for the wrongful use of his weapon. It also needlessly exposed the innocent bystander to death or grievous bodily harm. To discover the extent of this problem in West Virginia, a survey was made of the four major levels of police in the state: The state police, the county sheriffs and deputies, the city police, and the constables. The police departments of Pittsburgh and Philadelphia, Pennsylvania, were also consulted to obtain comparative data. The survey sought to determine what firearm policies exist and to elicit opinions on those policies. It also sought information on the need to codify such policies. Some of the areas surveyed included shooting at those fleeing from minor felonies; using warning shots; shooting at or from a moving vehicle; filing a written report when a firearm is discharged on duty; wearing of firearms off-duty; and employing a substitute for the lethal weapon. Commentators feel that by formulating and enforcing clear policies in these areas the police will avoid many tragic incidents that stifle police-community relations. The survey assumed the form of telephone interviews with various officers and chiefs in the departments. Selection of participants was made at random and attempted to secure a representative statewide geographic sample. Additionally, an effort was made to ascertain the effect of department size (in the case of county sheriffs, city police, and state police) and years of experience (in the case of constables) on the firearms policy. A total of forty agencies were interviewed. Bach representative was initially told the purpose of the interview and then was asked a series of questions designed to ascertain his department\u27s policies on the use of firearms. When the question was avoided or misunderstood, it was paraphrased and repeated. Participants were urged to give a definite answer to questions involving personal opinion

Alien Registration- Keegan, Thomas R. (Reed Plantation, Aroostook County)

https://digitalmaine.com/alien_docs/32767/thumbnail.jp

#Bigbirds never die: Understanding social dynamics of emergent hashtag

We examine the growth, survival, and context of 256 novel hashtags during the 2012 U.S. presidential debates. Our analysis reveals the trajectories of hashtag use fall into two distinct classes: “winners” that emerge more quickly and are sustained for longer periods of time than other “also-rans” hashtags. We propose a “conversational vibrancy” framework to capture dynamics of hashtags based on their topicality, interactivity, diversity, and prominence. Statistical analyses of the growth and persistence of hashtags reveal novel relationships between features of this framework and the relative success of hashtags. Specifically, retweets always contribute to faster hashtag adoption, replies extend the life of “winners” while having no effect on “also-rans.” This is the first study on the lifecycle of hashtag adoption and use in response to purely exogenous shocks. We draw on theories of uses and gratification, organizational ecology, and language evolution to discuss these findings and their implications for understanding social influence and collective action in social media more generally

The Impact of Ice Layers on Gas Transport through Firn at the North Greenland Eemian Ice Drilling (Neem) Site, Greenland

Typically, gas transport through firn is modeled in the context of an idealized firn column. However, in natural firn, imperfections are present, which can alter transport dynamics and therefore reduce the accuracy of reconstructed climate records. For example, ice layers have been found in several firn cores collected in the polar regions. Here, we examined the effects of two ice layers found in a NEEM, Greenland firn core on gas transport through the firn. These ice layers were found to have permeability values of 3.0 and 4.0 × 10−10 m2, and are therefore not impermeable layers. However, the shallower ice layer was found to be significantly less permeable than the surrounding firn, and can therefore retard gas transport. Large closed bubbles were found in the deeper ice layer, which will have an altered gas composition than that expected because they were closed near the surface after the water phase was present. The bubbles in this layer represent 12% of the expected closed porosity of this firn layer after the firn-ice transition depth is reached, and will therefore bias the future ice core gas record. The permeability and thickness of the ice layers at the North Greenland Eemian Ice Drilling (NEEM) site suggest that they do not disrupt the firn-air concentration profiles and that they do not need to be accounted for in gas transport models at NEEM

Progress report on the ultra heavy cosmic ray experiment (AO178)

The Ultra Heavy Cosmic Ray Experiment (UHCRE) is based on a modular array of 192 side-viewing solid state nuclear track detector stacks. These stacks were mounted in sets of four in 48 pressure vessels employing sixteen peripheral Long Duration Exposure Facility (LDEF) trays. The extended duration of the LDEF mission has resulted in a greatly enhanced scientific yield from the UHCRE. The geometry factor for high energy cosmic ray nuclei, allowing for Earth shadowing, was 30 sq m-sr, giving a total exposure factor of 170 sq m-sr-y at an orbital inclination of 28.4 degrees. Scanning results indicate that about 3000 cosmic ray nuclei in the charge region with Z greater than 65 were collected. This sample is more than ten times the current world data in the field (taken to be the data set from the HEAO-3 mission plus that from the Ariel-6 mission) and is sufficient to provide the world's first statistically significant sample of actinide (Z greater than 88) cosmic rays. Results to date are presented including details of ultra-heavy cosmic ray nuclei, analysis of pre-flight and post-flight calibration events and details of track response in the context of detector temperature history. The integrated effect of all temperature and age related latent track variations cause a maximum charge shift of +/- 0.8 e for uranium and +/- 0.6 e for the platinum-lead group. The precision of charge assignment as a function of energy is derived and evidence for remarkably good charge resolution achieved in the UHCRE is considered. Astrophysical implications of the UHCRE charge spectrum are discussed

The LDEF ultra heavy cosmic ray experiment

The LDEF Ultra Heavy Cosmic Ray Experiment (UHCRE) used 16 side viewing LDEF trays giving a total geometry factor for high energy cosmic rays of 30 sq m sr. The total exposure factor was 170 sq m sr y. The experiment is based on a modular array of 192 solid state nuclear track detector stacks, mounted in sets of four in 48 pressure vessels. The extended duration of the LDEF mission has resulted in a greatly enhanced potential scientific yield from the UHCRE. Initial scanning results indicate that at least 1800 cosmic ray nuclei with Z greater than 65 were collected, including the world's first statistically significant sample of actinides. Post flight work to date and the current status of the experiment are reviewed