The economic consequences of mortgage debt

Unsurprisingly, a great deal of attention has been paid to the economic consequences of the credit crunch. However, this paper shows that the credit crunch was preceded by a strong build-up of mortgage debt internationally, which, in the long run, could turn out to be more significant than the credit crunch itself. Indeed, the debt build-up suggests that the credit crunch is more likely to reoccur, because highly-indebted households have weaker buffers to withstand unexpected shocks to their incomes or to interest rates. The paper presents a model that can explain the debt build-up and changes to the distribution of debt between existing owners and first-time buyers, which hinders access to home-ownership for the latter, even amongst those households who would be considered as credit-worthy.     

How necessary is a fast testkit for mitigation of pandemic flu?

It is widely feared that a novel, highly pathogenic, human transmissible influenza virus may evolve that could cause the next global pandemic. Mitigating the spread of such an influenza pandemic would require not only the timely administration of antiviral drugs to those infected, but also the implementation of suitable intervention policies for stunting the spread of the virus. Towards this end, mathematical modelling and simulation studies are crucial as they allow us to evaluate the predicted effectiveness of the various intervention policies before enforcing them. Diagnosis plays a vital role in the overall pandemic management framework by detecting and distinguishing the pathogenic strain from the less threatening seasonal strains and other influenza-like illnesses. This allows treatment and intervention to be deployed effectively, given limited antiviral supplies and other resources. However, the time required to design a fast and accurate testkit for novel strains may limit the role of diagnosis. Herein, we aim to investigate the cost and effectiveness of different diagnostic methods using a stochastic agent-based city-scale model, and then address the issue of whether conventional testing approaches, when used with appropriate intervention policies, can be as effective as fast testkits in containing a pandemic outbreak. We found that for mitigation purposes, fast and accurate testkits are not necessary as long as sufficient medication is given, and are generally recommended only when used with extensive contact tracing and prophylaxis. Additionally, in the event of insufficient medication and fast testkits, the use of slower, conventional testkits together with proper isolation policies while waiting for the diagnostic results can be an equally effective substitute.     

The practice of vegetation survey and its relevance to landscape study in the uplands

The Canadian conservative ideology of an ordered controlled environment distinguished it from its revolutionary American neighbour. The ideology frequently involved Pastoral attitudes to nature. Only occasionally before the twentieth century did Canadian writers reveal negative views of their country's terrain.     

Infant sensitivity to trajectory forms.

The authors investigated whether infants are sensitive to visual event trajectory forms, and whether they are sensitive to the underlying dynamics of trajectory forms. The authors habituated 8-month-old infants to a videotaped event run either forward or reversed in time and then switched them to the same event run in the opposite direction. Infants dishabituated when switched to the event with the novel direction in time, indicating sensitivity to the form of the trajectory. Infants exhibited equivalent habituation rates and looking times for forward and reversed events, thus failing to provide evidence that infants are sensitive to the underlying dynamics. In a partial replication of this first experiment, the same pattern of results was found. Both experiments revealed infant sensitivity to the trajectory forms, but not the underlying dynamics of events. The authors discuss implications for methods used in infant event perception studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Design and initial operation of a 367-m2 rectangular ring laser

The design and operation of a proof-of-principle rectangular He-Ne ring laser resonator with a cavity perimeter of 77.0 m and an area of approximately 367 m2 are described. With unevacuated beam lines this device gave an Earth-induced Sagnac frequency of 1513 Hz, with a relative Allan deviation over 1000 s down to 3 parts per million. The Earth's rotation provided a bias that eliminated the lock-in susceptibility. The use of increased pressure in the plasma tube facilitated single-mode operation by increasing the homogeneous pressure-broadened linewidth.     

A hard-sphere model of the helium film

A quantum hard-sphere system bounded by two parallel rigid walls is studied at absolute zero as a model of a helium film. A variational wave function is constructed which is of the Bijl-Dingle-Jastrow type modified by a one-body term which vanishes at the walls; Monte Carlo quadrature is used. We focus our attention particularly on the behavior of the single-particle density function and the condensed-state wave function, i.e., the order parameter. Both show significantly different behavior from that predicted by the Hartree theory. The healing length is calculated, we believe for the first time, and is rather small. The average condensate as a function of distance between two walls is also investigated. The calculation serves as a special probe for approximations to the ground-state wave function in a uniform system.This work has been supported by the U.S. Atomic Energy Commission under contract # AT(11-1)-3077 and Grant No. GH-36457 with National Science Foundation.     

Combustion rate of bituminous coal char in the temperature range 800 to 1700 K

The combustion rates of three different sized fractions of char from a swelling bituminous coal have been measured in the temperature range 800 to 1700 K. The mass-median sizes of the fractions were 70, 35 and 18 μm. For each fraction the combustion rate was less than the limiting rate set by diffusion of oxygen to the particle. The chemical reaction rate coefficient (g/g s atm O₂), calculated from the measured rates and corrected for the external diffusion resistance, varied with temperature in a manner appropriate to an apparent activation energy of approximately 27 kcal/mol for the three fractions. The chemical reaction rate coefficient when expressed on the basis of unit external area of particle (g/cm² s atm O₂) increased with increasing particle size at 800 K: at 1250 K the coefficients for the 35 and 18 μm fractions were equal, and lower than those of the 70 μm fraction by a factor of 4. The densities of the particles did not vary appreciably with burn-off, except the density of the 70 μm fraction which increased sharply for values of burn-off between 0 and 0.01. It is probable that combustion occurred in a rate-control regime which was intermediate between that caused by chemical reaction alone and that caused by the combined effects of pore diffusion and chemical reaction.     

Chemical composition of degrading mangrove leaf litter and changes produced after consumption by mangrove crabNeosarmatium smithi (Crustacea: Decapoda: Sesarmidae)

The leaves of the mangroveCeriops tagal contained 3.2–4.1% (all percentages relate to dry weight) ofd-1-O-methyl-muco-inositol previously unreported in mangroves. They consisted of 37% aqueous acetone-water-soluble material, 18% water-insoluble polysaccharides, and ca. 50% polyphenols, which include soluble and insoluble tannins and lignin. The polysaccharide component sugars were glucose, arabinose, uronic acids, mannose, xylose, galactose, and rhamnose in the proportions 28262210752, respectively. The leaves were pectate rich, and the low level of glucan was presumed to consist mainly of cellulose. After four weeks of biodegradation, ca. 60% of the acetone-water-soluble material was lost from the leaves. Degradation processes greatly altered the polysaccharide components in the leaves. Pectates were rapidly degraded, while other polysaccharides, although reduced proportionately, resisted degradation at about the same level, and all component sugars were found in the 8-week-old leaves. Apparent lignin contents increased from 15 to >30% during biodegradation up to eight weeks. The yields of the major fractions in corresponding fecal material fromNeosarmatium smithi showed a similar trend to the diets. An enrichment of the insoluble residue was noticeable due to the digestion of dialyzable material. The fecal carbohydrate content was greatly reduced (7–11%) and the apparent lignin increased (27–39%) due to its resistance to degradation. All dietary polysaccharide component sugars were found in the fecal residues, including some uronic acids. The leaves also contained a readily water-soluble fraction (15%) which consisted of pectates strongly complexed with proanthocyanidins.