Time-symmetric boundary conditions and quantum foundations

Despite the widely-held premise that initial boundary conditions (BCs) corresponding to measurements/interactions can fully specify a physical subsystem, a literal reading of Hamilton's principle would imply that both initial and final BCs are required (or more generally, a BC on a closed hypersurface in spacetime). Such a time-symmetric perspective of BCs, as applied to classical fields, leads to interesting parallels with quantum theory. This paper will map out some of the consequences of this counter-intuitive premise, as applied to covariant classical fields. The most notable result is the contextuality of fields constrained in this manner, naturally bypassing the usual arguments against so-called "realistic" interpretations of quantum phenomena.Comment: 16 pages. With 0906.5409, companion paper to pirsa.org/09060031. v2: Minor edit, updates to reference

Political advertising is not polarizing the American public

There is little doubt that American politics has become more partisan and acrimonious in recent decades. While there are many potential sources of this rise in polarization, many point to the growth in political advertising as one potential cause. By combining survey and advertising data from US media markets, Travis N. Ridout, Erika Franklin Fowler, Michael Franz, and Ken Goldstein were able to investigate the effects of political advertising. They find that there is no link between political advertising and polarization or between the amount of negative or contrasting advertising and polarization

Understanding the effect of political advertising on voter turnout: A response to Krasno and Green

Krasno and Green have argued that political advertising has no impact on voter turnout. We remain unconvinced by their evidence, given concerns about how they measure the advertising environment, how they measure advertising tone, their choice of modeling techniques and the generalizability of their findings. These differences aside, we strongly agree that political advertising does little to undermine voter participation. © 2008 Southern Political Science Association

Development of a Light-Weight, Reliable, Booster System for SHELS-Launched Payloads

Small satellite missions are often used to support low-cost space missions demonstrating new technologies. An economical source of low-cost space lift is to fly these satellites as secondary payloads aboard the Space Shuttle. The Shuttle has accommodations for flying these payloads using the Shuttle Hitchhiker Experiment Launch System (SHELS). While the relative costs for a Shuttle launch are at least an order of magnitude below the cost of a dedicated Expendable Launch Vehicle (ELV), final orbit altitude selection is limited to Shuttle mission goals. The Air Force Space Test Program (STP) is responsible for flying the Space Experiments Review Board (SERB) recommended experiments on a level-of-effort basis. Low-cost space lift is crucial to maximizing the number of SERB payloads that STP can support. Unfortunately, the typical Shuttle orbit does not provide a high enough orbit to guarantee the oneyear orbital lifetime required to meet STP mission objectives. A low-cost, autonomous STP Transfer Upper stage, Guided (TUG) that can boost an STP payload from a typical Shuttle orbit to a higher, longer duration orbit would allow STP to take advantage of the low-cost space lift provided by the Shuttle and still meet their mission requirements. The Air Force Research Laboratory Space Vehicles Directorate (AFRL/VS) is pursuing a solution to fulfill STP’s satellite lifting requirements by developing a low-cost, lightweight, reliable, strap-on propulsion module using several Small Business Innovative Research (SBIR) contracts focused on various parts of the TUG system. The Shuttle Expendable Rocket for Payload Augmentation (SHERPA) program will integrate all of these SBIR programs to meet the STP TUG requirement. The TUG system would be composed of several technologies being developed or already developed by AFRL/VS such as separation systems, guidance systems, propulsion modules, and modular bus architecture. The TUG would be re-startable for multiple orbit changes, station keeping, or deorbiting at the completion of a mission. Three versions of the TUG are envisioned. The first is a simple propulsion module that uses the satellite\u27s Attitude Control System (ACS) and Guidance, Navigation, and Control (GN&C) to provide stack guidance. The second is a fully autonomous TUG that lifts the payload to the higher orbit as cargo, separates from the payload, and then accomplishes a collision avoidance maneuver and propellant burn after payload separation. The third configuration is an autonomous TUG with a long duration module that allow experiments to use the TUG\u27s ACS, GN&C, and power systems in the intended final orbit. There are many challenges in the development of this vehicle. The most difficult of these is meeting the man-rating requirements of the Shuttle. All critical systems must have triple redundancy to ensure that the system does not threaten the Shuttle, its crew, or its mission. Another complication is producing a structure that meets the strict mass and volume restrictions of the SHELS system. Integration is als o a challenge, as many contractors and technologies are brought together under this program

The Impact of NLO-Corrections on the Determination of the $\bar{u},\bar{d} Content of Nucleons from Drell-Yan Production

The interpretation of Drell-Yan production in terms of the antiquark densities depends on NLO corrections. Besides the NLO corrections to the familiar annihilation $q\bar{q}\to \gamma^* \to l^+ l^-$, there is a substantial contribution from the QCD Compton subprocesses $gq \to q\gamma^* \to q l^+ l^-$ and $g\bar{q} \to q\gamma^* \to q l^+ l^-$. The beam and target dependence of the two classes of corrections is different. We discuss the impact of this difference on the determination of the $\bar{d}-\bar{u}$ asymmetry in the proton from the comparison of the $pp$ and $pn$ Drell-Yan production.Comment: 4 pages, 1 eps-figure. To be published in Proceedings of DIS'9

Prolonged and tunable residence time using reversible covalent kinase inhibitors.

Drugs with prolonged on-target residence times often show superior efficacy, yet general strategies for optimizing drug-target residence time are lacking. Here we made progress toward this elusive goal by targeting a noncatalytic cysteine in Bruton's tyrosine kinase (BTK) with reversible covalent inhibitors. Using an inverted orientation of the cysteine-reactive cyanoacrylamide electrophile, we identified potent and selective BTK inhibitors that demonstrated biochemical residence times spanning from minutes to 7 d. An inverted cyanoacrylamide with prolonged residence time in vivo remained bound to BTK for more than 18 h after clearance from the circulation. The inverted cyanoacrylamide strategy was further used to discover fibroblast growth factor receptor (FGFR) kinase inhibitors with residence times of several days, demonstrating the generalizability of the approach. Targeting of noncatalytic cysteines with inverted cyanoacrylamides may serve as a broadly applicable platform that facilitates 'residence time by design', the ability to modulate and improve the duration of target engagement in vivo

Regulation of plasma LDL: the apoB paradigm

The objectives of this analysis are to re-examine the foundational studies of the in vivo metabolism of plasma LDL (low-density lipoprotein) particles in humans and, based on them, to reconstruct our understanding of the governance of the concentration of plasma LDL and the maintenance of cholesterol homoeostasis in the hepatocyte. We believe that regulation of cholesterol homoeostasis within the hepatocyte is demonstrably more complex than envisioned by the LDL receptor paradigm, the conventional model to explain the regulation of plasma LDL and the fluxes of cholesterol into the liver, a model which was generated in the fibroblast but has never been fully validated in the hepatocyte. We suggest that the LDL receptor paradigm should be reconfigured as the apoB (apolipoprotein B) paradigm, which states that the rate at which LDL particles are produced is at least an important determinant of their concentration in plasma as the rate at which they are cleared from plasma and that secretion of cholesterol within VLDL (very-low-density lipoprotein) particles is an important mechanism of maintaining cholesterol homoeostasis within the hepatocyte. These two paradigms are not mutually exclusive. The LDL receptor paradigm, however, includes only one critical aspect of the regulation of plasma LDL, namely the rate at which LDL particles are cleared through the LDL receptor pathway, but ignores another – the rate at which LDL particles are added to the plasma compartment. The apoB paradigm includes both and points to a different model of how the hepatocyte achieves cholesterol homoeostasis in a complex metabolic environment

Using automated medical records for rapid identification of illness syndromes (syndromic surveillance): the example of lower respiratory infection

BACKGROUND: Gaps in disease surveillance capacity, particularly for emerging infections and bioterrorist attack, highlight a need for efficient, real time identification of diseases. METHODS: We studied automated records from 1996 through 1999 of approximately 250,000 health plan members in greater Boston. RESULTS: We identified 152,435 lower respiratory infection illness visits, comprising 106,670 episodes during 1,143,208 person-years. Three diagnoses, cough (ICD9CM 786.2), pneumonia not otherwise specified (ICD9CM 486) and acute bronchitis (ICD9CM 466.0) accounted for 91% of these visits, with expected age and sex distributions. Variation of weekly occurrences corresponded closely to national pneumonia and influenza mortality data. There was substantial variation in geographic location of the cases. CONCLUSION: This information complements existing surveillance programs by assessing the large majority of episodes of illness for which no etiologic agents are identified. Additional advantages include: a) sensitivity, uniformity and efficiency, since detection of events does not depend on clinicians' to actively report diagnoses, b) timeliness, the data are available within a day of the clinical event; and c) ease of integration into automated surveillance systems. These features facilitate early detection of conditions of public health importance, including regularly occurring events like seasonal respiratory illness, as well as unusual occurrences, such as a bioterrorist attack that first manifests as respiratory symptoms. These methods should also be applicable to other infectious and non-infectious conditions. Knowledge of disease patterns in real time may also help clinicians to manage patients, and assist health plan administrators in allocating resources efficiently

A pilot Internet "Value of Health" Panel: recruitment, participation and compliance

Objectives To pilot using a panel of members of the public to provide preference data via the Internet Methods A stratified random sample of members of the general public was recruited and familiarised with the standard gamble procedure using an Internet based tool. Health states were perdiodically presented in "sets" corresponding to different conditions, during the study. The following were described: Recruitment (proportion of people approached who were trained); Participation (a) the proportion of people trained who provided any preferences and (b) the proportion of panel members who contributed to each "set" of values; and Compliance (the proportion, per participant, of preference tasks which were completed). The influence of covariates on these outcomes was investigated using univariate and multivariate analyses. Results A panel of 112 people was recruited. 23% of those approached (n = 5,320) responded to the invitation, and 24% of respondents (n = 1,215) were willing to participate (net = 5.5%). However, eventual recruitment rates, following training, were low (2.1% of those approached). Recruitment from areas of high socioeconomic deprivation and among ethnic minority communities was low. Eighteen sets of health state descriptions were considered over 14 months. 74% of panel members carried out at least one valuation task. People from areas of higher socioeconomic deprivation and unmarried people were less likely to participate. An average of 41% of panel members expressed preferences on each set of descriptions. Compliance ranged from 3% to 100%. Conclusion It is feasible to establish a panel of members of the general public to express preferences on a wide range of health state descriptions using the Internet, although differential recruitment and attrition are important challenges. Particular attention to recruitment and retention in areas of high socioeconomic deprivation and among ethnic minority communities is necessary. Nevertheless, the panel approach to preference measurement using the Internet offers the potential to provide specific utility data in a responsive manner for use in economic evaluations and to address some of the outstanding methodological uncertainties in this field