14,640 research outputs found
Cosmology with dropout selection: Straw-man surveys and CMB lensing
We seek to prove the means, motive and opportunity of 2 < z < 5 dropout
galaxies for large-scale structure. Together with low-z tracers, these samples
would map practically every linear mode and facilitate a tomographic
decomposition of the CMB lensing kernel over an unprecedented volume, thereby
yielding a proxy for (the time evolution of) matter density fluctuations that
provides compelling tests of horizon-scale General Relativity, neutrino masses
and Inflation-- viz., curvature, running of the spectral index and a
scale-dependent halo bias induced by (local) primordial non-Gaussianity.
Focusing on color-color selection, we estimate the completeness,
contamination, and spectroscopic survey speed of tailored Lyman-break galaxy
(LBG) samples. We forecast the potential of CMB lensing cross-correlation,
clustering redshifts and Redshift-Space Distortions (RSD) analyses. In
particular, we estimate: the depth dependence of interlopers based on CFHTLS
data and propagate this to biases in cosmology; new inferences of (non-linear)
halo bias at these redshifts and depths using legacy data; detailed forecasts
of LBG spectra as would be observed by DESI, PFS, and their successors. We
further assess the relative competitiveness of potential spectroscopic
facilities based on an intuitive figure-of-merit and define a modernisation of
traditional selections to the photometric system of LSST where necessary.
We confirm these science cases to be compelling for achievable facilities in
the next decade by defining a LBG sample of increasing Lyman-alpha equivalent
width with redshift, which delivers both percent-level RSD constraints on the
growth rate at high-z and measurements of CMB lensing cross-correlation at z=3
and 4 with a significance measured in the hundreds. Finally, we discuss the
limitations and avenues for improvement beyond this initial exploration
(abridged).Comment: 59 pages, comments welcom
Implementing a WTO agreement on trade facilitation : what makes sense ?
Contrary to the prevailing view that the Doha negotiations have achieved little, the authors find that on trade facilitation much progress has been made. This is particularly true in regard to action by development banks and bilateral development agencies to meet client demand for assistance in reform. Active private sector participation has been an important factor driving change. Many agencies have been involved in this work. The authors find that their roles have been consistent with their comparative advantages. As to how the international community can best support continued progress, the authors conclude in favor of a cautious approach to the imposition of new WTO obligations in the area of trade facilitation. On the whole, this is the approach the WTO has taken, for example, by limiting its negotiations on trade facilitation to several specific provisions of the GATT. The WTO can continue to function as a catalyst for reform. It is perhaps uniquely placed to relate the trade facilitation agenda to the overall trade agenda. On design and construction of the relevant infrastructures and capacities to spur development, the development institutions, including bilateral agencies, should continue to lead. The authors find little evidence to support the need for a comprehensive new"platform"or mechanism to channel trade-related aid as part of implementation of any new agreement at the WTO on trade facilitation. They recommend, however, that an innovative approach to using the well established, but under utilized Trade Policy Review Mechanism be considered to increase transparency on where new aid is going over time and to expand understanding of where and how country-based progress has been achieved.Economic Theory&Research,Trade Law,Trade Policy,Common Carriers Industry,Transport and Trade Logistics
A Split-Stem Lesion on Young Hybrid \u3ci\u3ePopulus\u3c/i\u3e Trees Caused by the Tarnished Plant Bug, \u3ci\u3eLygus Lineolaris\u3c/i\u3e (Hemiptera: [Heteroptera]: Miridae)
The tarnished plant bug, known principally as an agricultural pest, injures young hybrid Populus by feeding on the stems and meristems. Tarnished plant bug eggs, fungi associated with some lesions, and simple mechanical stimuli alone from feeding appeared not to cause lesion formation. Of 20 Populus hybrids tested in a clonal trial, four appeared to be consistently susceptible to lesion injury, with Populus nigra var. betulifolia x trichocarpa the most susceptible. Several clones showed high resistance in the trial but a few were susceptible in other plantings and in host preference tests when caged with tarnished plant bugs. Lesions diminished tenfold on Populus where horseweed, the insect\u27s principal wild host, grew along with susceptible poplars. The tarnished plant bug can be suppressed by ultra-low volume pesticides and cultural manipulation of understory vegetation
Weighted two-parameter Bergman space inequalities
For f , a function deļ¬ned on Rd1 ĆRd2 , take u to be its biharmonic extension into R+ +1 Ć Rd2 +1 . In this paper we prove strong d1 + suļ¬cient conditions on measures Āµ and weights v such that the inequality 1/q q ā2 u dĀµ(x1 , x2 , y1 , y2 ) d +1 d +1 R+1 ĆR+2 1/p ā¤ f p v dx Rd1 ĆRd2 will hold for all f in a reasonable test class, for 1 < p ā¤ 2 ā¤ q < ā. Our result generalizes earlier work by R. L. Wheeden and the author on one-parameter harmonic extensions. We also obtain suļ¬cient conditions for analogues of (ā) to hold when the entries of ā1 ā2 u are replaced by more general convolutions
Steady-state negative Wigner functions of nonlinear nanomechanical oscillators
We propose a scheme to prepare nanomechanical oscillators in nonclassical
steady states, characterized by a pronounced negative Wigner function. In our
optomechanical approach, the mechanical oscillator couples to multiple laser
driven resonances of an optical cavity. By lowering the resonance frequency of
the oscillator via an inhomogeneous electrostatic field, we significantly
enhance its intrinsic geometric nonlinearity per phonon. This causes the
motional sidebands to split into separate spectral lines for each phonon number
and transitions between individual phonon Fock states can be selectively
addressed. We show that this enables the preparation of the nanomechanical
oscillator in a single phonon Fock state. Our scheme can for example be
implemented with a carbon nanotube dispersively coupled to the evanescent field
of a state of the art whispering gallery mode microcavity
IDENTIFYING AN OPTIMIZATION TECHNIQUE FOR MAKER USAGE TO ADDRESS COVID-19 SUPPLY SHORTFALLS
Fused Deposition Modeling (FDM) can be purchased for under five hundred dollars. The availability of these inexpensive systems has created a large hobbyist (or maker) community. For makers, FDM printing is used numerous uses.
With the onset of the COVID-19 pandemic, the needs for Personal Protective Equipment (PPE) skyrocketed. COVID-19 mitigation strategies such as social distancing, businesses closures, and shipping delays created significant supply shortfalls. The maker community stepped in to fill gaps in PPE supplies.
In the case of 3DP, optimization remains the domain of commercial entities. Optimization is, at best, ad-hoc for makers. With the need to PPE supplies and COVID-19 related supply delays, optimization techniques would be of great value to makers.
The objective functions in this research is throughput and cost with quality factored into both. There are several parameters common to both throughput and surface roughness, including layer thickness, print speed, infill density, raster width, and wall thickness.
This research will utilize a 2-level fractional factorial design, in which process parameter had a specified upper (+1) and lower (-1) level. By using the upper and lower limits, this study will more closely align with the common maker workflow. The design will have a total of 16 trials, no main effect or 2-factor interactions are confounded with any other main effect or 2-factor interactions, this will allow the parameters to be estimated separately from one another without the requirement for conducting a full factorial (32 trials).
Least Squares Regression (OLS) will be completed on throughput and cost independently. Quality will be considered a component of both. For example, an OLS will be completed for the throughput to determine the respective effects of the process parameters on throughput. Using a 95% confidence interval, a process parameter with a P-value smaller that .05 will show that the process parameter has a significant effect on the throughput. Upon completion of each OLS model -Contraint methodology will be used to jointly optimize the process parameters. Validation trials will be completed to test the optimized process parameters. The results will be documented and discussed
Due Process for the Past Due: A Legal Aid Attorney\u27s Account of the Indigent Experience in Today\u27s Criminal Justice System
Benefits and Uses of Nematodes in Grassland Soils
To most grassland farmers nematodes mean trouble: they are important parasites of both pasture plants and livestock. While there is no doubting the considerable losses caused by nematodes, crop and livestock pests represent a tiny minority of the approximately 26,000 described nematode species. Here I examine the beneficial effects of nematodes within grassland systems and their beneficial uses. Nematodes in grassland soils increase plant available nutrients, move beneficial microbes through the rhizosphere and control insect and mollusc herbivores. We can use nematodes as biological control agents, and also as indicators of soil health/quality. While no single group of organisms can give a comprehensive overview of soil health, nematodes offer many advantages. In field soils, analysis of nematode abundance and diversity allows us to infer much about the soils health and function. Furthermore, the short lifespan and numerous biological techniques developed for the model nematode Caenorhabditis elegans makes this animal an excellent species for use in ecotoxicity testing. We can measure the wormās response at the molecular, behavioural and reproductive level. Nematodes thus have much potential for assessing risks and benefits associated with novel agricultural practices, agrochemicals and transgenic crops
The influence of habitat quality on the foraging strategies of the entomopathogenic nematodes Steinernema carpocapsae and Heterorhabditis megidis
Entomopathogenic nematodes (EPN) are soil-transmitted parasites and their foraging strategies are believed to range from āambushā to ācruiseā foragers. However, research on their behaviour has not considered the natural habitat of these nematodes. We hypothesized that EPN behaviour would be influenced by soil habitat quality and tested this hypothesis using 2 EPN species Steinernema carpocapsae (an āambusherā) and Heterorhabditis megidis (a ācruiserā) in 2 contrasting habitats, sand and peat. As predicted from previous studies, in sand most S. carpocapsae remained at the point of application and showed no taxis towards hosts, but in peat S. carpocapsae dispersed much more and showed a highly significant taxis towards hosts. H. megidis dispersed well in both media, but only showed taxis towards hosts in sand. In outdoor mesocosms in which both species were applied, S. carpocapsae outcompeted H. megidis in terms of host finding in peat, whereas the opposite was true in sand. Our data suggest that these 2 EPN may be habitat specialists and highlight the difficulties of studying soil-transmitted parasites in non-soil media
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