A Taxonomy of Communications Demand

Demand forecasts are an essential tool for planning capacity and formulating policy. Traffic estimates are becoming increasingly unreliable, however, as accelerating rates of use and new communications applications invalidate conventional forecasting assumptions. This paper presents an alternative approach to the study of telecommunications demand: build aggregate estimates for demand based on the elasticity of demand for bandwidth. We argue that price elasticity models are necessary to grasp the interaction between Moore-type technological progress and non-linear demand functions. Traditional marketing models are premised on existing or, at best, foreseeable services. But in a period of sustained price declines, applications-based forecasts will be unreliable. Dramatically lower prices can cause fundamental changes in the mix of applications and, hence, the nature of demand. We consider the option of posing demand theoretically in terms of service attributes. Our conclusion is that the positive feedback loop of technology-driven price decreases and high-elasticity demand will quickly make it possible to base forecasts on bandwidth elasticity alone. Industry analysts and policymakers need models of consumer demand applicable under dynamic conditions. We conclude by drawing implications of our demand model for network planning, universal service policies, and the commoditization of communications carriage

Experimental Investigation of Effects of Primary Jet Flow and Secondary Flow Through a Zero-length Ejector on Base and Boattail Pressures of a Body of Revolution at Free-stream Mach Numbers of 1.62, 1.93, and 2.41

An investigation was made at free-stream Mach numbers of 1.62, 1.93, and 2.41 to determine the effects of a primary jet and secondary air flow on the base pressure and pressures acting over the boattailsurface of a body of revolution for two secondary discharge areas. The Mach numbers of the primary nozzles were 1 and 3.23 with the secondary mass flow being varied from 0 to 10 percent of the primary mass flow. The ratio of jet stagnation temperature to tunnel stagnation temperature was about 0.96. The Reynolds number range of the investigation was from 2.1 x 10(6) to 2.9 x 10(6)based on body length. All testing was conducted with a turbulent boundary layer along the model. This report presents results obtained with zero-length ejector and covers jet static-pressure ratios from the jet-off condition to a maximum of about 128 for the sonic nozzle and to a maximum of about 9 for the supersonic nozzle

A New Rodent Model to Assess Blood Stage Immunity to the Plasmodium falciparum Antigen Merozoite Surface Protein 119 Reveals a Protective Role for Invasion Inhibitory Antibodies

Antibodies capable of inhibiting the invasion of Plasmodium merozoites into erythrocytes are present in individuals that are clinically immune to the malaria parasite. Those targeting the 19-kD COOH-terminal domain of the major merozoite surface protein (MSP)-119 are a major component of this inhibitory activity. However, it has been difficult to assess the overall relevance of such antibodies to antiparasite immunity. Here we use an allelic replacement approach to generate a rodent malaria parasite (Plasmodium berghei) that expresses a human malaria (Plasmodium falciparum) form of MSP-119. We show that mice made semi-immune to this parasite line generate high levels of merozoite inhibitory antibodies that are specific for P. falciparum MSP-119. Importantly, protection from homologous blood stage challenge in these mice correlated with levels of P. falciparum MSP-119–specific inhibitory antibodies, but not with titres of total MSP-119–specific immunoglobulins. We conclude that merozoite inhibitory antibodies generated in response to infection can play a significant role in suppressing parasitemia in vivo. This study provides a strong impetus for the development of blood stage vaccines designed to generate invasion inhibitory antibodies and offers a new animal model to trial P. falciparum MSP-119 vaccines

Leptogenesis in the minimal supersymmetric triplet seesaw model

In the supersymmetric triplet (type-II) seesaw model, in which a single SU(2)_L-triplet couples to leptons, the high-energy neutrino flavour structure can be directly determined from the low-energy neutrino data. We show that even with such a minimal triplet content, leptogenesis can be naturally accommodated thanks to the resonant interference between superpotential and soft supersymmetry breaking terms.Comment: References added, discussion expanded, to appear in PL

Ultra-High Temperature Distributed Wireless Sensors

Research was conducted towards the development of a passive wireless sensor for measurement of temperature in coal gasifiers and coal-fired boiler plants. Approaches investigated included metamaterial sensors based on guided mode resonance filters, and temperature-sensitive antennas that modulate the frequency of incident radio waves as they are re-radiated by the antenna. In the guided mode resonant filter metamaterial approach, temperature is encoded as changes in the sharpness of the filter response, which changes with temperature because the dielectric loss of the guided mode resonance filter is temperature-dependent. In the mechanically modulated antenna approach, the resonant frequency of a vibrating cantilever beam attached to the antenna changes with temperature. The vibration of the beam perturbs the electrical impedance of the antenna, so that incident radio waves are phase modulated at a frequency equal to the resonant frequency of the vibrating beam. Since the beam resonant frequency depends on temperature, a Doppler radar can be used to remotely measure the temperature of the antenna. Laboratory testing of the guided mode resonance filter failed to produce the spectral response predicted by simulations. It was concluded that the spectral response was dominated by spectral reflections of radio waves incident on the filter. Laboratory testing of the mechanically modulated antenna demonstrated that the device frequency shifted incident radio waves, and that the frequency of the re-radiated waves varied linearly with temperature. Radio wave propagation tests in the convection pass of a small research boiler plant identified a spectral window between 10 and 13 GHz for low loss propagation of radio waves in the interior of the boiler

One-way trip: Influenza virus' adaptation to gallinaceous poultry may limit its pandemic potential

We hypothesise that some influenza virus adaptations to poultry may explain why the barrier for human-to-human transmission is not easily overcome once the virus has crossed from wild birds to chickens. Since the cluster of human infections with H5N1 influenza in Hong Kong in 1997, chickens have been recognized as the major source of avian influenza virus infection in humans. Although often severe, these infections have been limited in their subsequent human-to-human transmission, and the feared H5N1 pandemic has not yet occurred. Here we examine virus adaptations selected for during replication in chickens and other gallinaceous poultry. These include altered receptor binding and increased pH of fusion of the haemagglutinin as well as stalk deletions of the neuraminidase protein. This knowledge could aid the delivery of vaccines and increase our ability to prioritize research efforts on those viruses from the diverse array of avian influenza viruses that have greatest human pandemic potential

Catastrophic payments for health care in Asia

Out-of-pocket (OOP) payments are the principal means of financing health care throughout much of Asia. We estimate the magnitude and distribution of OOP payments for health care in fourteen countries and territories accounting for 81% of the Asian population. We focus on payments that are catastrophic, in the sense of severely disrupting household living standards, and approximate such payments by those absorbing a large fraction of household resources. Bangladesh, China, India, Nepal and Vietnam rely most heavily on OOP financing and have the highest incidence of catastrophic payments. Sri Lanka, Thailand and Malaysia stand out as low to middle income countries that have constrained both the OOP share of health financing and the catastrophic impact of direct payments. In most low/middle-income countries, the better-off are more likely to spend a large fraction of total household resources on health care. This may reflect the inability of the poorest of the poor to divert resources from other basic needs and possibly the protection of the poor from user charges offered in some countries. But in China, Kyrgyz and Vietnam, where there are no exemptions of the poor from charges, they are as, or even more, likely to incur catastrophic payments

Distinct Body Mass Index Trajectories to Young-Adulthood Obesity and Their Different Cardiometabolic Consequences.

[Figure: see text]

Digital humanities, digital methods, digital history, and digital outputs: history writing and the digital revolution

While the term ‘digital humanities’ appears inclusive its exact meaning remains unclear and its early association with studies in English Literature means the term has already been partially superceded by ‘digital methods’. However that re-naming is problematic as it emphasises the research tools used while the field itself is adjusting to include new methods, new topics, and new types of production, not just new ways of working with existing materials. Historians have long been alert to new tools as they become available to researchers. However, even as historians have revelled in the increased access to primary sources provided by digitisation, and have analysed the opportunities that access offers, they have been aware of the unevenness of the digitisation process and the gaps it both creates and disguises. Issues of copyright and the ethics of creating public access to private lives have also caused historians concern. More recently discussion about the evaluation of digital scholarship has begun. Often purely digital outputs are not formally recognised by their authors’ institutions, despite having a significant online presence and contributing to scholarship. In parallel with being concerned about fairly assessing the work of peers, historians have also begun to consider how to teach (and assess) the digital skills now expected of history graduates

Cortisol metabolism, postnatal depression and weight changes in the first 12 months postpartum

Background & Objectives Postnatal depression correlates with postpartum weight retention, and dysregulated cortisol metabolism is evident in depressed individuals. Cortisol metabolism, BMI and metabolic phenotype are robustly associated, but the role of cortisol metabolism in postnatal mental health and weight loss has never been examined. Design A longitudinal observation. Patients Forty nine healthy women with uncomplicated pregnancy. Measurements BMI and urinary steroid metabolites at 1 week and 1, 3, 6 and 12 months postpartum. Validated urinary steroid metabolite ratios were measured to determine the activities of 11β‐hydroxysteroid dehydrogenases (11β‐HSD) that interconvert inactive cortisone and active cortisol and the 5α‐reductases that clear cortisol to its inactive metabolites. Postnatal depression symptoms were measured at 1, 6 and 12 months. Results Low 5α‐reductase activity was associated with greater weight loss across the first year, independent of demographics, breastfeeding and depression. Postpartum BMI change was unrelated to postnatal depression at any time. Symptoms of postnatal depression were related to higher cortisol metabolite production at 12 months, independent of demographics and breastfeeding. Conclusions Greatest weight loss in the postpartum year was associated with lower conversion of cortisone to cortisol and lower conversion of cortisol to its metabolites, supporting previous work that demonstrates the facilitative role of lower 5α‐reductase and 11β‐HSD‐1 in weight loss. Greater depression symptoms were associated with higher cortisol metabolite production rates. Whilst weight and mental health are both associated with dysregulation of the HPA axis, there may be different pathways towards depressed and obese phenotypes in healthy postpartum samples