The Role of Context and Content on Recognition Accuracy in Virtual Worlds

We investigate differences in recognition accuracy of visual vs. text content presented in two contexts – virtual world (imagery processing) vs. Web browser (discursive processing). In three studies, one completed and two planned, we address the conditions under which a match or mismatch between content and context improves recognition accuracy

Simulating multiple merger pathways to the central kinematics of early-type galaxies

Two-dimensional integral field surveys such as ATLAS^3D are producing rich observational data sets yielding insights into galaxy formation. These new kinematic observations have highlighted the need to understand the evolutionary mechanisms leading to a spectrum of fast-rotators and slow-rotators in early-type galaxies. We address the formation of slow and fast rotators through a series of controlled, comprehensive hydrodynamical simulations sampling idealized galaxy merger scenarios constructed from model spiral galaxies. Idealized and controlled simulations of this sort complement the more 'realistic' cosmological simulations by isolating and analyzing the effects of specific parameters, as we do in this paper. We recreate minor and major binary mergers, binary merger trees with multiple progenitors, and multiple sequential mergers. Within each of these categories of formation history, we correlate progenitor gas fraction, mass ratio, orbital pericenter, orbital ellipticity, and spin with remnant kinematic properties. We create kinematic profiles of these 95 simulations comparable to ATLAS^3D data. By constructing remnant profiles of the projected specific angular momentum (lambda_R = / , triaxiality, and measuring the incidences of kinematic twists and kinematically decoupled cores, we distinguish between varying formation scenarios. We find that binary mergers nearly always form fast rotators. Slow rotators can be formed from zero initial angular momentum configurations and gas-poor mergers, but are not as round as the ATLAS^3D galaxies. Remnants of binary merger trees are triaxial slow rotators. Sequential mergers form round slow rotators that most resemble the ATLAS^3D rotators.Comment: MNRAS, in press, 12 pages, 15 figure

cAMP inhibits induction of interleukin 2 but not of interleukin 4 in T cells

In this report, we explore the nature of the inductive stimuli leading to expression of the divergently regulated lymphokines interleukin 2 (IL-2) and interleukin 4 (IL-4). Elevation of cAMP levels blocks IL-2 induction while sparing IL-4 induction. These effects are gene-specific, not cell-specific, and can be observed in the same cells. Transient transfection experiments using murine IL-2 regulatory sequences to drive expression of a reporter gene show at least part of the inhibition to act at the transcriptional level. The possible biological significance of these results is indicated by the observation that representative type 2 helper T-cell lines maintain significantly higher levels of cAMP per cell than a type 1 helper T-cell line. Fresh splenic CD4+ T cells, which preferentially make IL-2, have particularly low levels of cAMP per cell and a low capacity to elevate cAMP in response to forskolin. However, their response to forskolin increases significantly after several days of stimulation. These results suggest a potential link between differential cAMP regulation and the divergence of memory T cells into effector subsets

Biofuels for Aviation

Paraffinic Kerosene fuels are the backbone of commercial air travel. Kerosene fuels are primarily derived from petroleum processing and contribute significantly to carbon emissions globally. A variety of processes have been proposed to create renewable or semi-renewable sources of kerosene fuel suitable for aviation. One such process outlined in a 2019 white paper published by Gevo proposes the use of bio-based alcohol feed stocks to produce isobutanol which may be converted to kerosene mixtures through well-established dehydration and oligomerizations processes. The proposed Alcohol to Jet Fuel Pathway (ATJ-SPK) is a potentially net carbon neutral process which can greatly reduce the emissions generated by commercial air travel. The pathway would also allow airlines to integrate green Synthetic Paraffinic Fuel technology without expensive overhaul of existing fleets to accommodate new fuel sources, or research currently infeasible electric air travel (Gevo, 2019). A plant was designed around the use of a Nickel-FM catalyst to convert feedstocks of ethanol and methanol to isobutanol via the Guerbet chemistry pathway (Olson et al., 2004). Due to the presence of side reactions and excess methanol feed, distillation and liquid-liquid separation were proposed as methods of delivering an isobutanol-water mixture to the downstream dehydration and oligomerization steps. The economics of the downstream processes are estimated and included in the profitability analysis along with a detailed estimation of the isobutanol production step. Selling the fuel product at market price was not found to be profitable; however, if a green premium of 4.55x is applied to the product fuel price the plant is 2 both technically and economically feasible. With the green premium levied on the price of the product fuel the Internal Rate of Return (IRR) is 15%, with a Net Present Value (NPV) of $51.7 MM, and a third year Return on Investment (ROI) of 13.58%. Significant market research is needed to assess the viability of the green premium that must be levied on the fuel price to yield a reasonable return. It may be the case that it is currently inadvisable to invest in the proposed plant but may become advisable in the coming years as consumer and regulatory awareness begins to grow over the environmental impacts of air travel

Experimental and Numerical Investigation of the Effect of Integration of a Flooded-Bed Scrubber into a Longwall Shearer on Airflow along a Coal Mine Longwall Face

Dust control is one of the most difficult challenges for underground coal mine operators, especially longwall mine operators. The most widely used dust control technologies at a longwall section are ventilation air and water sprays, whereas a continuous miner section has the added advantage of having a dust scrubber built into the continuous miner. To test the potential benefits of integrating a flooded-bed scrubber into a longwall shearer, the authors designed and built a dust scrubber system for a full-scale mock-up of a longwall shearer. The mock-up was installed in the longwall test gallery at the Pittsburgh Research Laboratory (PRL) for testing. Air quantity surveys were performed at different cross-sections of the test gallery at a fixed face-air quantity, but at different scrubber airflow rates to quantify the distribution of air in the test gallery. Subsequently, a computational fluid dynamics (CFD) model of the PRL test gallery was developed and validated. In this study, the effect of the flooded-bed scrubber on airflow pattern in the test gallery is investigated using the validated CFD model. This model can be used further to predict the dust capture efficiency of the scrubber and to develop new techniques to reduce dust concentration in longwall sections

Shapes of Stellar Systems and Dark Halos from Simulations of Galaxy Major Mergers

Using a sample of 89 snapshots from 58 hydrodynamic binary galaxy major merger simulations, we find that stellar remnants are mostly oblate while dark matter halos are mostly prolate or triaxial. The stellar minor axis and the halo major axis are almost always nearly perpendicular. This can be understood by considering the influence of angular momentum and dissipation during the merger. If binary mergers of spiral galaxies are responsible for the formation of elliptical galaxies or some subpopulation thereof, these galaxies can be expected to be oblate and inhabit their halos with the predicted shapes and orientations. These predictions are potentially relevant to observational studies of weak gravitational lensing, where one must stack many optically aligned galaxies in order to determine the shape of the resulting stacked mass distribution. The simple relationship between the dark and luminous matter presented here can be used to guide the stacking of galaxies to minimize the information lost.Comment: 4 pages, 5 figures. Minor changes to match published versio

Bacterial growth properties at low optical densities

A method for accurate quantification of growth rate and yield of bacterial populations at low densities was developed with a modified version of a stepwise linear model for fitting growth curves based on optical density measurements, and adapted to measurements at low optical densities in 96-well microtiter plates. The method can be used for rapid and precise estimates of growth rate and yield, based on optical density measurements of large numbers of cultures of Escherichia coli. E. coli B lines were serially propagated at low glucose concentration during a long-term evolution experiment. Growth rate and yield of populations sampled from each of 12 lines that evolved for 20,000 generations under these conditions and two ancestral clones was measured. Populations were grown at three different glucose concentrations. Consistent with earlier findings, statistical analysis showed that both exponential growth rate and yield per unit of glucose differed significantly between the three glucose concentrations tested. Significant adaptation of the evolved populations to the nutrient conditions in which they evolved for 20,000 generations was observe

Development of Lead Free Energy Absorber for Space Shuttle Blast Container

The Space Shuttle is connected to the mobile launch platform (MLP) by four aft skirt hold down studs on each solid rocket booster (SRB). Prior to lift-off, the frangible nuts inside the aft skirt blast containers are severed into two nut halves by two pyrotechnic booster cartridges. This action releases the Space Shuttle and allows the hold down studs to eject through the aft skirt bore and then down into the MLP. USBI has been tasked to upgrade the blast container for two specific reasons: (1) To eliminate lead for environmental concerns, and (2) To reduce the chance of nut recontact with the holddown stud. Nut recontact with the stud has been identified as a likely contributor to stud hang-ups. This upgrade will replace the lead liner with a unique open cell aluminum foam material, that has commercial and military uses. The aluminum foam used as an energy absorber is a proven design in many other aerospace/defense applications. Additional benefits of using the open cell, energy absorbent aluminum foam in place of the solid lead liner are: (A) Lead handling/exposure and possible contamination, along with hazardous waste disposal, will be eliminated; (B) Approximately 200 lbs. weight savings will be contributed to each Space Shuttle flight by using aluminum foam instead of lead; (C) The new aluminum liner is designed to catch all shrapnel from frangible nuts, thus virtually eliminating chance of debris exiting the HDP and causing potential damage to the vehicle; and (D) Using the lighter aluminum liner instead of lead, allows for easier assembly and disassembly of blast container elements, which also improves safety, operator handling, and the efficiency of operations

Root‐derived trans‐zeatin cytokinin protects Arabidopsis plants against photoperiod stress

Recently, a novel type of abiotic stress caused by a prolongation of the light period - coined photoperiod stress - has been described in Arabidopsis. During the night after the prolongation of the light period, stress and cell death marker genes are induced. The next day, strongly stressed plants display a reduced photosynthetic efficiency and leaf cells eventually enter programmed cell death. The phytohormone cytokinin (CK) acts as a negative regulator of this photoperiod stress syndrome. In this study, we show that Arabidopsis wild‐type plants increase the CK concentration in response to photoperiod stress. Analysis of cytokinin synthesis and transport mutants revealed that root‐derived trans‐zeatin (tZ)‐type CKs protect against photoperiod stress. The CK signalling proteins ARABIDOPSIS HISTIDINE PHOSPHOTRANSFER PROTEIN 2 (AHP2), AHP3 and AHP5 and transcription factors ARABIDOPSIS RESPONSE REGULATOR 2 (ARR2), ARR10 and ARR12 are required for the protective activity of CK. Analysis of higher order B‐type arr mutants suggested that a complex regulatory circuit exists in which the loss of ARR10 or ARR12 can rescue the arr2 phenotype. Together the results revealed the role of root‐derived CK acting in the shoot through the two‐component signalling system to protect from the negative consequences of strong photoperiod stress

UML Based Specifications of PDM Product Structure and Workflow

The paper deals with the use of UML approach for the specification of a PDM system. A PDM enables the management of the product data about its entire lifecycle. The main goal of the paper is to highlight the added value of in using an object-oriented approach to modelling and implementing a PDM in a business case study