Empirically-Based Warehouse Design: Can Academics Accept Such an Approach?

It is our opinion that existing research is not sufficient to support the design of a warehouse. As a result, facility designers that work in practice are left to face the design process with their own methods. These methods are in stark contrast to the analytical models developed in academia in that they are highly based on empirical observations. Supported by a collection of empirical observations, facility designers who work in practice employ an ad hoc design process. We present a design process based on empirical observations and then formalize it so that it can be taught and used. We illustrate the process with an example and discuss ways in which analytical methods can be used to supplement the process and improve the design. We conclude by describing additional work that is required if the design process is to be realized

An arctic hydrologic system in transition: Feedbacks and impacts on terrestrial, marine, and human life

The pace of change in the arctic system during recent decades has captured the world\u27s attention. Observations and model simulations both indicate that the arctic experiences an amplified response to climate forcing relative to that at lower latitudes. At the core of these changes is the arctic hydrologic system, which includes ice, gaseous vapor in the atmosphere, liquid water in soils and fluvial networks on land, and the freshwater content of the ocean. The changes in stores and fluxes of freshwater have a direct impact on biological systems, not only of the arctic region itself, but also well beyond its bounds. In this investigation, we used a heuristic, graphical approach to distill the system into its fundamental parts, documented the key relationships between those parts as best we know them, and identified the feedback loops within the system. The analysis illustrates relationships that are well understood, but also reveals others that are either unfamiliar, uncertain, or unexplored. The graphical approach was used to provide a visual assessment of the arctic hydrologic system in one possible future state in which the Arctic Ocean is seasonally ice free

Characteristics of cat skeletal muscles grafted with intact nerves or with anastomosed nerves

Grafting of 3-g extensor digitorum longus (EDL) muscles of cats may be made with (i) severence of the nerve with spontaneous reinnervation, termed standard grafts (ii) severence of the nerve with reinnervation facilitated by anastomosis of the nerve, termed nerve-anastomosed grafts; and (iii) preservation of the nerve, termed nerveintact grafts. In previous studies, standard grafts developed a maximum isometric tetanic tension (P0) that was 22% of the value for control EDL muscles. We hypothesized that the low values of P0 resulted from incomplete reinnervation of muscle fibers. To test this hypothesis, EDL muscles were grafted in cats with nerves intact and with nerves anastomosed. In standard grafts differences were observed in both structure and function at 120 compared with 240 days after grafting. Characteristics of the nerve-intact and nerve-anastomosed grafts did not change significantly between 120 and 240 days and the data were pooled for comparisons with control EDL muscles. Nerve-anastomosed and nerve-intact grafts developed P0 values that were 34 and 64% of the control values, respectively. Nerve-intact grafts had a mass and fiber cross-sectional area not different from control EDL muscles. Compared with control values, all grafts had fewer fibers, more connective tissue, lower absolute and normalized P0, reduced capillary density, and increased fatigability. The greater P0 of nerve-intact compared with standard and nerve-anastomosed grafts supported our hypothesis that the degree of reinnervation is a factor that limits graft development. The presence of a necrotic core and the low tension development of even the nerve-intact grafts suggested that revascularization is a significant limitation as well.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25210/1/0000650.pd

Changes in the Economy and Ecology at Proposed Lake Sites in the Salt River Basin, Kentucky, During Early Construction of the Dam for Taylorsville Lake

This is an extension of the work reported in Project numbers B-005-KY, B-016-KY, and B-022-KY that extended from 1 July 1968 through 30 June 1972. Permanent collecting stations have been established at 67 sites throughout the Salt River, Beech Fork, and Chaplin River drainages. Turbidities increases quickly as flow and runoff increase, and subside quickly when the rain stops. Suspended solids range up to 1,700 mg/l in high turbidities and vary considerably as a result of local spates. Water chemistry generally reflects the limestone nature of the substrate and physico-chemical characteristics of a typically healthy limestone stream. Bottom organisms are abundant and diverse, more than 300 different benthic organisms have been identified to date

Five High-Redshift Quasars Discovered in Commissioning Imaging Data of the Sloan Digital Sky Survey

We report the discovery of five quasars with redshifts of 4.67 - 5.27 and z'-band magnitudes of 19.5-20.7 M_B ~ -27. All were originally selected as distant quasar candidates in optical/near-infrared photometry from the Sloan Digital Sky Survey (SDSS), and most were confirmed as probable high-redshift quasars by supplementing the SDSS data with J and K measurements. The quasars possess strong, broad Lyman-alpha emission lines, with the characteristic sharp cutoff on the blue side produced by Lyman-alpha forest absorption. Three quasars contain strong, broad absorption features, and one of them exhibits very strong N V emission. The amount of absorption produced by the Lyman-alpha forest increases toward higher redshift, and that in the z=5.27 object (D_A ~ 0.7) is consistent with a smooth extrapolation of the absorption seen in lower redshift quasars. The high luminosity of these objects relative to most other known objects at z >~ 5 makes them potentially valuable as probes of early quasar properties and of the intervening intergalactic medium.Comment: 13 pages in LaTex format, two postscirpt figures. Submitted to the Astronomical Journa

High-Redshift Quasars Found in Sloan Digital Sky Survey Commissioning Data IV: Luminosity Function from the Fall Equatorial Stripe Sampl

This is the fourth paper in a series aimed at finding high-redshift quasars from five-color imaging data taken along the Celestial Equator by the SDSS. during its commissioning phase. In this paper, we use the color-selected sample of 39 luminous high-redshift quasars presented in Paper III to derive the evolution of the quasar luminosity function over the range of 3.6<z<5.0, and -27.5<M_1450<-25.5 (Omega=1, H_0=50 km s^-1 Mpc^-1). We use the selection function derived in Paper III to correct for sample incompleteness. The luminosity function is estimated using three different methods: (1) the 1/V_a estimator; (2) a maximum likelihood solution, assuming that the density of quasars depends exponentially on redshift and as a power law in luminosity and (3) Lynden-Bell's non-parametric C^- estimator. All three methods give consistent results. The luminous quasar density decreases by a factor of ~ 6 from z=3.5 to z=5.0, consistent with the decline seen from several previous optical surveys at z<4.5. The luminosity function follows psi(L) ~ L^{-2.5} for z~4 at the bright end, significantly flatter than the bright end luminosity function psi(L) \propto L^{-3.5} found in previous studies for z<3, suggesting that the shape of the quasar luminosity function evolves with redshift as well, and that the quasar evolution from z=2 to 5 cannot be described as pure luminosity evolution. Possible selection biases and the effect of dust extinction on the redshift evolution of the quasar density are also discussed.Comment: AJ accepted, with minor change

Quasi-coherent fluctuations limiting the pedestal growth on Alcator C-Mod: experiment and modelling

Performance predictions for future fusion devices rely on an accurate model of the pedestal structure. The candidate for predictive pedestal structure is EPED, and it is imperative to test the underlying hypotheses to further gain confidence for ITER projections. Here, we present experimental work testing one of the EPED hypotheses, namely the existence of a soft limit set by microinstabilities such as the kinetic ballooning mode. This work extends recent work on Alactor C-Mod (Diallo et al 2014 Phys. Rev. Lett. 112 115001), to include detailed measurements of the edge fluctuations and comparisons of edge simulation codes and experimental observations

Span of control in supervision of rail track work

The supervision of engineering work on the railways has received relatively little examination despite being both safety-critical in its own right and having wider implications for the successful running of the railways. The present paper is concerned with understanding the factors that make different engineering works perceived as easier or harder to manage. We describe an approach building on notions of ‘span of control’, through which we developed the TOECAP inventory (Team, Organisation, Environment, Communication, Activity and Personal). This tool was validated through both interviews and questionnaires. As well as identifying the physical factors involved, the work also emphasised the importance of collaborative and attitudinal factors. We conclude by discussing limitations of the present work and future directions for development

Acupressure for smoking cessation – a pilot study

BACKGROUND: Tobacco smoking is a serious risk to health: several therapies are available to assist those who wish to stop. Smokers who approach publicly funded stop-smoking clinics in the UK are currently offered nicotine replacement therapy (NRT) or bupropion, and group behaviour therapy, for which there is evidence of effectiveness. Acupuncture and acupressure are also used to help smokers, though a systematic review of the evidence of their effectiveness was inconclusive. The aim of this pilot project was to determine the feasibility of a study to test acupressure as an adjunct to one anti-smoking treatment currently offered, and to inform the design of the study. METHODS: An open randomised controlled pilot study was conducted within the six week group programme offered by the Smoking Advice Service in Plymouth, UK. All participants received the usual treatment with NRT and group behavioural therapy, and were randomised into three groups: group A with two auricular acupressure beads, group B with one bead, and group C with no additional therapy. Participants were taught to press the beads when they experienced cravings. Beads were worn in one ear for four weeks, being replaced as necessary. The main outcome measures assessed in the pilot were success at quitting (expired CO ≤ 9 ppm), the dose of NRT used, and the rating of withdrawal symptoms using the Mood and Symptoms Scale. RESULTS: From 49 smokers attending four clinics, 24 volunteered to participate, 19 attended at least once after quitting, and seven remained to the final week. Participants who dropped out reported significantly fewer previous quit attempts, but no other significant differences. Participants reported stimulating the beads as expected during the initial days after quitting, but most soon reduced the frequency of stimulation. The discomfort caused by the beads was minor, and there were no significant side effects. There were technical problems with adhesiveness of the dressing. Reporting of NRT consumption was poor, with much missing data, but reporting of ratings of withdrawal symptom scores was nearly complete. However, these showed no significant changes or differences between groups for any week. CONCLUSION: Any effects of acupressure on smoking withdrawal, as an adjunct to the use of NRT and behavioural intervention, are unlikely to be detectable by the methods used here and further preliminary studies are required before the hypothesis can be tested

Explaining Cold-Pulse Dynamics in Tokamak Plasmas Using Local Turbulent Transport Models

A long-standing enigma in plasma transport has been resolved by modeling of cold-pulse experiments conducted on the Alcator C-Mod tokamak. Controlled edge cooling of fusion plasmas triggers core electron heating on time scales faster than an energy confinement time, which has long been interpreted as strong evidence of nonlocal transport. This Letter shows that the steady-state profiles, the cold-pulse rise time, and disappearance at higher density as measured in these experiments are successfully captured by a recent local quasilinear turbulent transport model, demonstrating that the existence of nonlocal transport phenomena is not necessary for explaining the behavior and time scales of cold-pulse experiments in tokamak plasmas.United States. Department of Energy (Award DE-FC02-99ER54512)United States. Department of Energy (Grant DESC0014264