Asynchronous video telephony for the Deaf

The South African Deaf community has very limited telephony options. They prefer to communicate in sign language, a visual medium. Realtime video over Internet Protocol is a promising option, but in reality, the quality is often not enough for the Deaf to be able to understand each other’s sign language. Furthermore, these applications were not design specifically for the Deaf. This paper introduces an asynchronous video chat system to provide better quality video at the expense of increased latency. It determined a codec/transmission protocol combination in the laboratory environment and tested it out with actual Deaf users. This paper will address the results based on comparison between different codecs, transmission protocol on asynchronous video communication for the Deaf.Telkom, Cisco, THRIP, SANPADDepartment of HE and Training approved lis

Adapting x264 to asynchronous video telephony for the Deaf

Deaf people want to communicate remotely with sign language. Sign language requires sufficient video quality to be intelligible. Internet-based real-time video tools do not provide that quality. Our approach is to use asynchronous transmission to maintain video quality. Unfortunately, this entails a corresponding increase in latency. To reduce latency as much as possible, we sought to adapt a synchronous video codec to an asynchronous video application. First we compared several video codecs with subjective and objective metrics. This paper describes the process by which we chose x264 and integrated it into a Deaf telephony video application, and experimented to configure x264 optimally for the asynchronous environment.Telkom, Cisco, THRIP, SANPADDepartment of HE and Training approved lis

A mixed-fidelity numerical study for Fan-Distortion interaction

Inlet distortion often occurs under off-design conditions when a flow separates within an intake and this unsteady phenomenon can seriously impact fan performance. Fan–distortion interaction is a highly unsteady aerodynamic process into which high-fidelity simulations can provide detailed insights. However, due to limitations on the computational resource, the use of an eddy resolving method for a fully resolved fan calculation is currently infeasible within industry. To solve this problem, a mixed-fidelity computational fluid dynamics method is proposed. This method uses the large Eddy simulation (LES) approach to resolve the turbulence associated with separation and the immersed boundary method (IBM) with smeared geometry (IBMSG) to model the fan. The method is validated by providing comparisons against the experiment on the Darmstadt Rotor, which shows a good agreement in terms of total pressure distributions. A detailed investigation is then conducted for a subsonic rotor with an annular beam-generating inlet distortion. A number of studies are performed in order to investigate the fan's influence on the distortions. A comparison to the case without a fan shows that the fan has a significant effect in reducing distortions. Three fan locations are examined which reveal that the fan nearer to the inlet tends to have a higher pressure recovery. Three beams with different heights are also tested to generate various degrees of distortion. The results indicate that the fan can suppress the distortions and that the recovery effect is proportional to the degree of inlet distortion.</jats:p

Revisiting the Female Germline and Its Expanding Toolbox

The Arabidopsis thaliana ovule arises as a female reproductive organ composed solely of somatic diploid cells. Among them, one cell will acquire a unique identity and initiate female germline development. In this review we explore the complex network that facilitates differentiation of this single cell, and consider how it becomes committed to a distinct developmental program. We highlight recent progress towards understanding the role of intercellular communication, cell competency, and cell-cycle regulation in the ovule primordium, and we discuss the possibility that distinct pathways restrict germline development at different stages. Importantly, these recent findings suggest a renaissance in plant ovule research, restoring the female germline as an attractive model to study cell communication and cell fate establishment in multicellular organs

Mammal population densities at a global scale are higher in human‐modified areas

Global landscapes are changing due to human activities with consequences for both biodiversity and ecosystems. For single species, terrestrial mammal population densities have shown mixed responses to human pressure, with both increasing and decreasing densities reported in the literature. How the impacts of human activities on mammal populations translates into altered global density patterns remains unclear. Here we aim to disentangle the effect of human impacts on large‐scale patterns of mammal population densities using a global dataset of 6729 population density estimates for 468 mammal species (representing 59% and 44% of mammalian orders and families). We fitted a mixed effect model to explain the variation in density based on a 1‐degree resolution as a function of the human footprint index (HFI), a global proxy of direct and indirect human disturbances, while accounting for body mass, trophic level and primary productivity (normalized vegetation index; NDVI). We found a significant positive relationship between population density and HFI, where population densities were higher in areas with a higher HFI (e.g. agricultural or suburban areas – no populations were located in very high HFI urban areas) compared to areas with a low HFI (e.g. wilderness areas). We also tested the effect of the individual components of the HFI and still found a consistent positive effect. The relationships remained positive even across populations of the same species, although variability among species was high. Our results indicate shifts in mammal population densities in human modified landscapes, which is due to the combined effect of species filtering, increased resources and a possible reduction in competition and predation. Our study provides further evidence that macroecological patterns are being altered by human activities, where some species will benefit from these activities, while others will be negatively impacted or even extirpated

Effect of Fan on Inlet Distortion: Mixed-fidelity Approach

Inlet distortion is typically encountered during off-design conditions on civil aircraft and in S-ducts in military aircraft. It is known to cause severe deterioration to the performance of a gas-turbine engine. As intakes become shorter, there is an increased interaction between the inlet distortion and the downstream fan. Previous studies in the literature use Reynolds-averaged Navier–Stokes or unsteady Reynolds-averaged Navier–Stokes to model this unsteady interaction, due to the substantial computational cost associated with high-fidelity methods such as large-eddy simulation/direct numerical simulation. On the other hand, it is well known that turbulence models have limitations in terms of predicting distorted flows. In this paper, a mixed-fidelity approach is proposed and employed to study the intake–fan interaction at an affordable computational cost. The results demonstrate that there are two mechanisms via which the fan affects the separated flow. First, the suction effect of the fan (effective up to almost half of the chord length upstream of the fan) alleviates the undesired distortion by “directly” changing the streamline curvature, intensifying the turbulence transport and closing the recirculation bubble much earlier. Second, the enhanced turbulence in the vicinity of the fan feeds back into the initial growth of the shear layer by means of the recirculating flow. This “indirect” feedback is found to increase turbulence production during the initial stages of formation of the shear layer. Both the direct and indirect effects of the fan significantly suppress the inlet distortion.The authors acknowledge the computing time on the UK national high-performance computing service ARCHER provided via the UK Turbulence Consortium in the framework of the EPSRC grant EP/L000261/1. This work is funded by a studentship from the Chinese Scholarship Council. The code for this project is provided by the Rolls-Royce plc

Boston Hospitality Review: Spring 2016

Understanding the Momentum and Motivations of Foreign Investors in U.S. Hospitality by Ken Wilson and Liya Ma -- Creating Memorable Experiences: How hotels can fight back against Airbnb and other sharing economy providers by Makarand Mody -- Rebranding Before the Digital Age: 4 Strategies Used by the Sheraton New York Hotel and Towers During the 1992 Democratic National Convention by Leora Halpern Lanz, Juan Lesmes, and Erinn Tucker -- Federal Minimum Wage Debate: Are Gubernatorial Politics Behind a Hotel Line Employee Wage? by Nicholas Thomas and Eric Brown -- Rethinking Substance Use and Abuse Among Hospitality Employees by Amir Shani -- Consumers’ Desires in Hostels: Addressing Latent and Explicit Needs in United States Hostels by Emily Horto

An analog of adjoint ideals and PLT singularities in mixed characteristic

We use the framework of perfectoid big Cohen-Macaulay algebras to define a class of singularities for pairs in mixed characteristic, which we call purely BCM-regular singularities, and a corresponding adjoint ideal. We prove that these satisfy adjunction and inversion of adjunction with respect to the notion of BCM-regularity and the BCM test ideal defined by the first two authors. We compare them with the existing equal characteristic PLT and purely $F$-regular singularities and adjoint ideals. As an application, we obtain a uniform version of the Brian\c{c}on-Skoda theorem in mixed characteristic. We also use our theory to prove that two-dimensional KLT singularities are BCM-regular if the residue characteristic $p>5$, which implies an inversion of adjunction for three-dimensional PLT pairs of residue characteristic $p>5$. In particular, divisorial centers of PLT pairs in dimension three are normal when $p > 5$. Furthermore, in the appendix we provide a streamlined construction of perfectoid big Cohen-Macaulay algebras and show new functoriality properties for them using the perfectoidization functor of Bhatt and Scholze

Genes of the GadX-GadW Regulon in Escherichia coli

Acid in the stomach is thought to be a barrier to bacterial colonization of the intestine. Escherichia coli, however, has three systems for acid resistance, which overcome this barrier. The most effective of these systems is dependent on transport and decarboxylation of glutamate. GadX regulates two genes that encode isoforms of glutamate decarboxylase critical to this system, but additional genes associated with the glutamate-dependent acid resistance system remained to be identified. The gadX gene and a second downstream araC-like transcription factor gene, gadW, were mutated separately and in combination, and the gene expression profiles of the mutants were compared to those of the wild-type strain grown in neutral and acidified media under conditions favoring induction of glutamate-dependent acid resistance. Cluster and principal-component analyses identified 15 GadX-regulated, acid-inducible genes. Reverse transcriptase mapping demonstrated that these genes are organized in 10 operons. Analysis of the strain lacking GadX but possessing GadW confirmed that GadX is a transcriptional activator under acidic growth conditions. Analysis of the strain lacking GadW but possessing GadX indicated that GadW exerts negative control over three GadX target genes. The strain lacking both GadX and GadW was defective in acid induction of most but not all GadX target genes, consistent with the roles of GadW as an inhibitor of GadX-dependent activation of some genes and an activator of other genes. Resistance to acid was decreased under certain conditions in a gadX mutant and even more so by combined mutation of gadX and gadW. However, there was no defect in colonization of the streptomycin-treated mouse model by the gadX mutant in competition with the wild type, and the gadX gadW mutant was a better colonizer than the wild type. Thus, E. coli colonization of the mouse does not appear to require glutamate-dependent acid resistance