2,053 research outputs found
COMBINING ECONOMIC AND BIOLOGICAL DATA TO ESTIMATE THE IMPACT OF POLLUTION ON CROP PRODUCTION
Duality methods utilizing a profit function framework are employed to estimate the output elasticity of ambient ozone levels on cash grain farms in Illinois. While duality methods have been recommended as a cure to many of the statistical problems of direct estimation of production functions, multicollinearity may still be a problem. A method for utilizing stochastic information on parameters of a seemingly unrelated system of equations, which is implied by profit function estimation, is developed and applied to measuring the impact of ozone. Such an approach may be necessary in measuring other environmental effects because of a lack of regressor variability.Crop Production/Industries, Environmental Economics and Policy,
Bootstrapping six-gluon scattering in planar super-Yang-Mills theory
We describe the hexagon function bootstrap for solving for six-gluon
scattering amplitudes in the large limit of super-Yang-Mills
theory. In this method, an ansatz for the finite part of these amplitudes is
constrained at the level of amplitudes, not integrands, using boundary
information. In the near-collinear limit, the dual picture of the amplitudes as
Wilson loops leads to an operator product expansion which has been solved using
integrability by Basso, Sever and Vieira. Factorization of the amplitudes in
the multi-Regge limit provides additional boundary data. This bootstrap has
been applied successfully through four loops for the maximally helicity
violating (MHV) configuration of gluon helicities, and through three loops for
the non-MHV case.Comment: 15 pages, 3 figures, 2 tables; contribution to the proceedings of
Loops and Legs in Quantum Field Theory, 27 April - 2 May 2014, Weimar,
Germany; v2, reference adde
The four-loop remainder function and multi-Regge behavior at NNLLA in planar = 4 super-Yang-Mills theory
We present the four-loop remainder function for six-gluon scattering with maximal helicity violation in planar N = 4 super-Yang-Mills theory, as an analytic function of three dual-conformal cross ratios. The function is constructed entirely from its analytic properties, without ever inspecting any multi-loop integrand. We employ the same approach used at three loops, writing an ansatz in terms of hexagon functions, and fixing coefficients in the ansatz using the multi-Regge limit and the operator product expansion in the near-collinear limit. We express the result in terms of multiple polylogarithms, and in terms of the coproduct for the associated Hopf algebra. From the remainder function, we extract the BFKL eigenvalue at next-to-next-to-leading logarithmic accuracy (NNLLA), and the impact factor at N3LLA. We plot the remainder function along various lines and on one surface, studying ratios of successive loop orders. As seen previously through three loops, these ratios are surprisingly constant over large regions in the space of cross ratios, and they are not far from the value expected at asymptotically large orders of perturbation theory
Quantum Mutual Information Capacity for High Dimensional Entangled States
High dimensional Hilbert spaces used for quantum communication channels offer
the possibility of large data transmission capabilities. We propose a method of
characterizing the channel capacity of an entangled photonic state in high
dimensional position and momentum bases. We use this method to measure the
channel capacity of a parametric downconversion state, achieving a channel
capacity over 7 bits/photon in either the position or momentum basis, by
measuring in up to 576 dimensions per detector. The channel violated an
entropic separability bound, suggesting the performance cannot be replicated
classically.Comment: 5 pages, 2 figure
Targeted interventions for patellofemoral pain syndrome (TIPPS): classification of clinical subgroups
Introduction Patellofemoral pain (PFP) can cause significant pain leading to limitations in societal participation and physical activity. An international expert group has highlighted the need for a classification system to allow targeted intervention for patients with PFP; we have developed a work programme systematically investigating this. We have proposed six potential subgroups: hip abductor weakness, quadriceps weakness, patellar hypermobility, patellar hypomobility, pronated foot posture and lower limb biarticular muscle tightness. We could not uncover any evidence of the relative frequency with which patients with PFP fell into these subgroups or whether these subgroups were mutually exclusive. The aim of this study is to provide information on the clinical utility of our classification system.
Methods and analysis 150 participants will be recruited over 18â
months in four National Health Services (NHS) physiotherapy departments in England. Inclusion criteria: adults 18â40â
years with PFP for longer than 3â
months, PFP in at least two predesignated functional activities and PFP elicited by clinical examination. Exclusion criteria: prior or forthcoming lower limb surgery; comorbid illness or health condition; and lower limb training or pregnancy. We will record medical history, demographic details, pain, quality of life, psychomotor movement awareness and knee temperature. We will assess hip abductor and quadriceps weakness, patellar hypermobility and hypomobility, foot posture and lower limb biarticular muscle tightness.
The primary analytic approach will be descriptive. We shall present numbers and percentages of participants who meet the criteria for membership of (1) each of the subgroups, (2) none of the subgroups and (3) multiple subgroups. Exact (binomial) 95% CIs for these percentages will also be presented.
Ethics and dissemination This study has been approved by National Research Ethics Service (NRES) Committee North WestâGreater Manchester North (11/NW/0814) and University of Central Lancashire (UCLan) Built, Sport, Health (BuSH) Ethics Committee (BuSH 025). An abstract has been accepted for the third International Patellofemoral Pain Research Retreat, Vancouver, September 2013
Anisotropic winds from close-in extra-solar planets
We present two-dimensional hydrodynamic models of thermally driven winds from
highly irradiated, close-in extra-solar planets. We adopt a very simple
treatment of the radiative heating processes at the base of the wind, and
instead focus on the differences between the properties of outflows in
multidimensions in comparison to spherically symmetric models computed with the
same methods. For hot (T > 2 x 10^{4} K) or highly ionized gas, we find strong
(supersonic) polar flows are formed above the planet surface which produce weak
shocks and outflow on the night-side. In comparison to a spherically symmetric
wind with the same parameters, the sonic surface on the day-side is much closer
to the planet surface in multidimensions, and the total mass loss rate is
reduced by almost a factor of four. We also compute the steady-state structure
of interacting planetary and stellar winds. Both winds end in a termination
shock, with a parabolic contact discontinuity which is draped over the planet
separating the two shocked winds. The planetary wind termination shock and the
sonic surface in the wind are well separated, so that the mass loss rate from
the planet is essentially unaffected. However, the confinement of the planetary
wind to the small volume bounded by the contact discontinuity greatly enhances
the column density close to the planet, which might be important for the
interpretation of observations of absorption lines formed by gas surrounding
transiting planets.Comment: ApJ accepte
Characterisation of the carboxypeptidase G2 catalytic site and design of new inhibitors for cancer therapy
The enzyme carboxypeptidaseâ
G2 (CPG2) is used in antibodyâdirected enzyme prodrug therapy (ADEPT) to catalyse the formation of an active drug from an inert prodrug. Free CPG2 in the bloodstream must be inhibited before administration of the prodrug in order to avoid a systemic reaction in the patient. Although a few smallâmolecule CPG2 inhibitors have been reported, none has been taken forward thus far. This lack of progress is due in part to a lack of structural understanding of the CPG2 active site as well as the absence of small molecules that can block the active site whilst targeting the complex for clearance. The work described here aimed to address both areas. We report the structural/functional impact of extensive point mutation across the putative CPG2 catalytic site and adjacent regions for the first time, revealing that residues outside the catalytic region (K208A, S210A and T357A) are crucial to enzyme activity. We also describe novel molecules that inhibit CPG2 whilst maintaining the accessibility of galactosylated moieties aimed at targeting the enzyme for clearance. This work acts as a platform for the future development of highâaffinity CPG2 inhibitors that occupy new chemical space and will advance the safe application of ADEPT in cancer treatment
The Steinmann Cluster Bootstrap for N=4 Super Yang-Mills Amplitudes
We review the bootstrap method for constructing six- and seven-particle
amplitudes in planar super Yang-Mills theory, by exploiting
their analytic structure. We focus on two recently discovered properties which
greatly simplify this construction at symbol and function level, respectively:
the extended Steinmann relations, or equivalently cluster adjacency, and the
coaction principle. We then demonstrate their power in determining the
six-particle amplitude through six and seven loops in the NMHV and MHV sectors
respectively, as well as the symbol of the NMHV seven-particle amplitude to
four loops.Comment: 36 pages, 4 figures, 5 tables, 1 ancillary file. Contribution to the
proceedings of the Corfu Summer Institute 2019 "School and Workshops on
Elementary Particle Physics and Gravity" (CORFU2019), 31 August - 25
September 2019, Corfu, Greec
Controlled release of GAG-binding enhanced transduction (GET) peptides for sustained and highly efficient intracellular delivery
Controlled release systems for therapeutic molecules are vital to allow the sustained local delivery of their activities which direct cell behaviour and enable novel regenerative strategies. Direct programming of cells using exogenously delivered transcription factors can by-pass growth factor signalling but there is still a requirement to deliver such activity spatio-temporally. We previously developed a technology termed GAG-binding enhanced transduction (GET) to efficiently deliver a variety of cargoes intracellularly, using GAG-binding domains which promote cell targeting, and cell penetrating peptides (CPPs) which allow cell entry. Herein we demonstrate that GET system can be used in controlled release systems to mediate sustained intracellular transduction over one week. We assessed the stability and activity of GET peptides in poly(dl-lactic acid-co-glycolic acid) (PLGA) microparticles (MPs) prepared using a S/O/W double emulsion method. Efficient encapsulation (âŒ65%) and tailored protein release profiles could be achieved, however intracellular transduction was significantly inhibited post-release. To retain GET peptide activity we optimized a strategy of co-encapsulation of l-Histidine, which may form a complex with the PLGA degradation products under acidic conditions. Simulations of the polymer microclimate showed that hydrolytic acidic PLGA degradation products directly inhibited GET peptide transduction activity, and use of l-Histidine significantly enhanced released protein delivery. The ability to control the intracellular transduction of functional proteins into cells will facilitate new localized delivery methods and allow approaches to direct cellular behaviour for many regenerative medicine applications
Ice Patch Archaeology in Alaska: 2000â10
In the past decade, ice patch archaeological research has been initiated in several areas of Alaska, including Wrangell-St. Elias National Park and Preserve, the Amphitheater Mountains, Lake Clark National Park and Preserve, Denali National Park and Preserve, Gates of the Arctic National Park and Preserve, Chugach National Forest, and Katmai National Park. Although still in its formative stages, this research demonstrates that high-altitude ice patches have been an important part of the annual subsistence cycles of Alaskan people for at least 4000 years. Researchers have found cultural materials at 13 Alaskan ice patches. Most artifacts recovered are related to caribou hunting; however, a growing body of evidence demonstrates that ice patches were the foci for a wide range of subsistence activities, such as hunting birds, harvesting berries, and snaring small mammals. Site interpretations are based on ethnographically documented cultural practices, animal behavior, alpine ecology and geology, and archaeological analyses.Au cours de la derniĂšre dĂ©cennie, des recherches archĂ©ologiques ont Ă©tĂ© entreprises dans plusieurs nĂ©vĂ©s de lâAlaska, notamment dans les rĂ©gions suivantes : Wrangell-St. Elias National Park and Preserve, monts Amphitheater, Lake Clark National Park and Preserve, Denali National Park and Preserve, Gates of the Arctic National Park and Preserve, Chugach National Forest et Katmai National Park. Bien que ces recherches en soient toujours au stade embryonnaire, elles ont dĂ©jĂ permis de constater que les nĂ©vĂ©s en haute altitude ont jouĂ© un rĂŽle important dans les cycles de subsistance annuels des peuples de lâAlaska pendant au moins 4 000 ans. Les chercheurs ont rĂ©cupĂ©rĂ© du matĂ©riel culturel dans 13 nĂ©vĂ©s de lâAlaska. La plupart des artefacts qui ont Ă©tĂ© trouvĂ©s se rapportent Ă la chasse au caribou. Cependant, de plus en plus dâartefacts prouvent que les nĂ©vĂ©s Ă©taient le point de convergence dâune vaste gamme dâactivitĂ©s de subsistance, comme la chasse aux oiseaux, la rĂ©colte des petits fruits et le piĂ©geage des petits mammifĂšres. LâinterprĂ©tation des sites sâappuie sur les pratiques culturelles documentĂ©es de maniĂšre ethnographique, sur le comportement animal, sur lâĂ©cologie et la gĂ©ologie alpines ainsi que sur les analyses archĂ©ologiques
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