A wind-tunnel and analytical study of the conversion from wing lift to rotor lift on a composite-lift V/TOL aircraft

Wind tunnel and analytical study of conversion from wing lift to rotor lift on composite lift VTOL aircraf

Collider Inclusive Jet Data and the Gluon Distribution

Inclusive jet production data are important for constraining the gluon distribution in the global QCD analysis of parton distribution functions. With the addition of recent CDF and D0 Run II jet data, we study a number of issues that play a role in determining the up-to-date gluon distribution and its uncertainty, and produce a new set of parton distributions that make use of that data. We present in detail the general procedures used to study the compatibility between new data sets and the previous body of data used in a global fit. We introduce a new method in which the Hessian matrix for uncertainties is ``rediagonalized'' to obtain eigenvector sets that conveniently characterize the uncertainty of a particular observable.Comment: Published versio

On Compact Routing for the Internet

While there exist compact routing schemes designed for grids, trees, and Internet-like topologies that offer routing tables of sizes that scale logarithmically with the network size, we demonstrate in this paper that in view of recent results in compact routing research, such logarithmic scaling on Internet-like topologies is fundamentally impossible in the presence of topology dynamics or topology-independent (flat) addressing. We use analytic arguments to show that the number of routing control messages per topology change cannot scale better than linearly on Internet-like topologies. We also employ simulations to confirm that logarithmic routing table size scaling gets broken by topology-independent addressing, a cornerstone of popular locator-identifier split proposals aiming at improving routing scaling in the presence of network topology dynamics or host mobility. These pessimistic findings lead us to the conclusion that a fundamental re-examination of assumptions behind routing models and abstractions is needed in order to find a routing architecture that would be able to scale ``indefinitely.''Comment: This is a significantly revised, journal version of cs/050802

Neutrino Dimuon Production and the Strangeness Asymmetry of the Nucleon

We have performed the first global QCD analysis to include the CCFR and NuTeV dimuon data, which provide direct constraints on the strange and anti-strange parton distributions, $s(x)$ and $\bar{s}(x)$. To explore the strangeness sector, we adopt a general parametrization of the non-perturbative $s(x), \bar{s}(x)$ functions satisfying basic QCD requirements. We find that the strangeness asymmetry, as represented by the momentum integral $[S^{-}]\equiv \int_0^1 x [s(x)-\bar{s}(x)] dx$, is sensitive to the dimuon data provided the theoretical QCD constraints are enforced. We use the Lagrange Multiplier method to probe the quality of the global fit as a function of $[S^-]$ and find $-0.001 < [S^-] < 0.004$. Representative parton distribution sets spanning this range are given. Comparisons with previous work are made.Comment: 23 pages, 4 figures; expanded version for publicatio

The Role of Non-Recurring Congestion in Massive Hurricane Evacuation Events

The response to a potential disaster can require the evacuation of personnel from a specified area. Generally, such efforts are restricted to the orderly mass departure of individuals across pre-planned and well maintained transportation routes. In the U.S., evacuations of up to 1,000 subjects take place every two to three weeks, with more extreme evacuations involving two million or more every one to three years (TRB, 2008). While evacuation routes are designed to accommodate normal traffic movements, congestion and gridlock can occur as the design capacity of the road system is overwhelmed by the magnitude of vehicles leaving the affected area. The resulting traffic patterns affect the safety and mobility of subjects moving to more secure areas. Adding to this disarray, potential nonrecurring incidents congest traffic patterns even more. Estimates indicate that between fifty and sixty-five percent of traffic congestion is caused by non-recurring traffic incidents with an additional ten percent related to construction and weather (Coifman, 2007). A non-recurring traffic incident is any event that both causes a reduction of roadway capacity, or an abnormal increase in demand, and requires first responders to be dispatched. Stalled vehicles, roadway debris, spilled loads, and crashes fall into this category of incidents. Non-recurring traffic incidents can cause secondary traffic incidents. These incidents further congest the traffic stream and cause delays in clean-up efforts by first-responders. Studies indicate that twenty percent of traffic incidents are secondary incidents, with one out of five resulting in a fatality. In addition to crashes, secondary incidents can include overheated vehicles, out of fuel conditions, and engine stalls. The delay and traffic gridlock associated with traffic incidents is compounded during the evacuation process due to the large numbers of subjects leaving the affected area. These delays and backups result in: ⢠Increased response time by first responders ⢠Lost time resulting in a wider evacuation window ⢠Increased fuel consumption ⢠Reduced air quality and other adverse environmental conditions ⢠Increased potential for more serious secondary incidents resulting from rear end collisions, traffic exiting the route, or exiting to the shoulder of the road ⢠Increased potential of crashes by incidents involving personnel responding to traffic incidents ⢠Negative public image of first responders involved in incident management activities

Stability of NLO Global Analysis and Implications for Hadron Collider Physics

The phenomenology of Standard Model and New Physics at hadron colliders depends critically on results from global QCD analysis for parton distribution functions (PDFs). The accuracy of the standard next-to-leading-order (NLO) global analysis, nominally a few percent, is generally well matched to the expected experimental precision. However, serious questions have been raised recently about the stability of the NLO analysis with respect to certain inputs, including the choice of kinematic cuts on the data sets and the parametrization of the gluon distribution. In this paper, we investigate this stability issue systematically within the CTEQ framework. We find that both the PDFs and their physical predictions are stable, well within the few percent level. Further, we have applied the Lagrange Multiplier method to explore the stability of the predicted cross sections for W production at the Tevatron and the LHC, since W production is often proposed as a standard candle for these colliders. We find the NLO predictions on sigma_W to be stable well within their previously-estimated uncertainty ranges.Comment: 24 pages, 11 figures. Minor changes in response to JHEP referee repor

kt Effects in Direct-Photon Production

We discuss the phenomenology of initial-state parton-kt broadening in direct-photon production and related processes in hadron collisions. After a brief summary of the theoretical basis for a Gaussian-smearing approach, we present a systematic study of recent results on fixed-target and collider direct-photon production, using complementary data on diphoton and pion production to provide empirical guidance on the required amount of kt broadening. This approach provides a consistent description of the observed pattern of deviation of next-to-leading order QCD calculations relative to the direct-photon data, and accounts for the shape and normalization difference between fixed-order perturbative calculations and the data. We also discuss the uncertainties in this phenomenological approach, the implications of these results on the extraction of the gluon distribution of the nucleon, and the comparison of our findings to recent related work.Comment: LaTeX, uses revtex and epsf, 37 pages, 15 figure

Pretreatment With Fragments of Substance-P or With Cholecystokinin Differentially Affects Recovery From Sub-Total Nigrostriatal 6-Hydroxydopamine Lesion

The neuropeptide substance P is known to have mnemogenic and reinforcing actions and can exert neurotrophic and regenerative effects in vitro as well as in vivo. Furthermore, our previous work in the rat showed that either pre- or post-lesion treatment with substance P can promote functional recovery in cases of partial nigrostriatal dopamine lesions. Other work has provided evidence that the effects of substance P might be differentially encoded by its C- and N-terminal fragments. The C-terminal fragment was found to be reinforcing, whereas the mnemogenic as well as neurotrophic properties have been ascribed to the N-terminal sequences. Given these relations, we asked here whether pre-lesion treatment with either a C- or an N-terminal fragment of substance P might differentially affect the behavioral and neurochemical outcome of nigrostriatal dopamine lesions. Therefore, either substance P1−7 or substance P5−11 (37 nmol/kg each) was administered intraperitoneally daily for eight consecutive days before unilateral 6-hydroxy-dopamine lesions of the substantia nigra. Control rats received prelesion treatment with vehicle. Furthermore, we investigated the effects of pre-treatment with Boc-cholecystokinin-4 (0.91 nmol/kg), as we had found an increase in dopamine metabolism in animals that were pre-treated with cholecystokinin-8 in a former study. In accordance with our previous work, drug treatment effects were observed when excluding animals with most severe dopamine lesions: In animals with partial lesions (residual neostriatal dopamine levels of more than 10%), lesion-dependent asymmetries in turning behavior were observed in animals that were pre-treated with vehicle-, substance P1−7 , or Boc-cholecysto-kinin–4,. whereas turning after pre-treatment with substance P5−11 was not significantly asymmetrical. Furthermore, the ipsi- and contra-lateral neostriatal dopamine levels did not differ significantly in this group. Moreover, pre treatment with substance P5−11 affected dopamine metabolism in the neostriatum and in the venral striatum, as indicated by increased ratios of dihydroxyphenyllic acid to dopamine. The data provide the first evidence that the promotive effects of substance-P treatment in the unilateral dopamine lesion model might be mediated by its C-terminal and might depend on actions on residual dopamine mechanisms