The Effect of Income Risk, Asset Risk and Policy Risk on Household Behaviour

This thesis quantitatively examines the types of risk that households face, how they prepare for these risks, and the effect of these risks on inequality. The first substantive chapter reviews the evolution of inequality over 1978 to 2005 in the UK along several dimensions and serves as an introduction to subsequent chapters. Following the inequality surge in the 1980s, inequality generally rose more slowly in the 1990s on most measures. The second chapter seeks to explain a puzzling episode in the evolution of inequality in the late 1990s: consumption inequality rose while income inequality fell. I explain this episode by accounting for two features of the UK economy over the period: a house price boom and a sequence of redistributive reforms by the new Labour government. I conclude that asset price movements and government policies can have a noticeable effect on `permanent' (consumption) inequality and that the redistributive effect of the reforms was largely undone by the coincident house price boom. The third chapter uses panel data over 1991 to 2006 to estimate the transmission of income shocks through to consumption. Only around 50% of `permanent' income shocks are transmitted. This estimate reconciles two views of risk over the period: long-lasting income fluctuations, measured by panel data on incomes alone, were high, while consumption risk, measured by the growth in consumption inequality, was much lower. The results further indicate that such income `shocks' are either not fully permanent or are often foreseen by younger households. The fourth chapter theoretically examines the precautionary savings motive for consecutive income risks. In most cases (and particularly when facing permanent shocks) households can combine saving for near-term risks with saving for long-term risks. I term this saving `complementary'. However, in some interesting cases, the interaction of future risks ampli es the precautionary motive

Consumption of Aquatic Plants by the West Indian Manatee

Because manatees (Trichechus manatus) are large aquatic herbivores they have often been considered as potential control agents for aquatic plants. Several problems are associated with this concept, and a major one has been the gap in knowledge concerning food consumption rates of manatees. We estimated food consumption by measuring chews per unit time, chews per amount of food consumed, and time spent chewing food. Data were collected on captive manatees of various sizes and used to construct regression equations that predict consumption rates based on body size. Time budget data were obtained by radiotelemetry of free-ranging animals. Estimates of consumption rates for manatees eating hydrilla (Hydrilla verticillata Royle) were compared to the estimates biomass of hydrilla in Kings Bay, Florida, the overwintering site for a large manatee populations (116 in the winter of 1980-1981). Estimates show that nearly ten times as many manatees would have been needed just to consume the standing biomass of hydrilla. The inefficiency of manatees as control agents for aquatic plants becomes even more apparent when plant productivity is included in these estimates

Experimental investigation of mixing in a stratified fluid due to diffusion-driven flows in a loosely-packed particle layer

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (p. 16).An experimental study was undertaken to investigate if a loosely-packed particle layer can induce mixing due to diffusion-driven Phillips-Wunsch boundary flows in a quiescent stratified fluid. Diffusion-driven flows can exist along a sloped boundary in a fluid with a density gradient that varies with height, so these flows will also exist along the curved surface of a spherical boundary. A particle layer was created using 6.35 mm diameter Polystyrene spheres in a salt-stratified fluid. A linear density stratification was pumped into an acrylic tank from below using a double-bucket system. A calibrated salinity probe, mounted on a computer-controlled traverse, was used to measure the evolution of the density profile in the tank over time. The results of the density profiles showed a measurable change in the density profile in the tank over several weeks. The density profile in the area vertically adjacent to the particle layer was nonlinear due to mixing induced by the Phillips-Wunsch boundary flows created by the spherical particles.by William B. Etheridge.S.B

The results of compression forces applied to the isolated human calvaria

Data for the force necessary to fracture the isolated calvaria (skull cap) are not available in the extant literature. Twenty dry adult calvaria were tested to failure quasistatically at the vertex using a 15-kN load cell. The forces necessary to fracture or cause diastasis of calvarial sutures were then documented and gross examination of the specimens made. Failure forces had a mean measurement of 2772 N. Initial fractures did not cross suture lines. Prior to complete destruction of the calvaria there were 7 specimens in which all sutures of the calvaria became diastatic, 6 specimens in which the calvaria became diastatic along only the coronal sutures, 2 specimens in which the calvaria became diastatic along only the sagittal suture and 5 specimens in which there were diagonal linear parietal bone fractures. Our hopes are that these data may contribute to the structural design of more safer protective devices for use in our society, assist in predicting injury and aid in the construction of treatment paradigms

Vertically reciprocating auger

The mathematical model and test results developed for the Vertically Reciprocating Auger (VRA) are summarized. The VRA is a device capable of transporting cuttings that result from below surface drilling. It was developed chiefly for the lunar surface, where conventional fluid flushing while drilling would not be practical. The VRA uses only reciprocating motion and transports material through reflections with the surface above. Particles are reflected forward and land ahead of radially placed fences, which prevent the particles from rolling back down the auger. Three input wave forms are considered to drive the auger. A modified sawtooth wave form was chosen for testing, over a modified square wave or sine wave, due to its simplicity and effectiveness. The three-dimensional mathematical model predicted a sand throughput rate of 0.2667 pounds/stroke, while the actual test setup transported 0.075 pounds/stroke. Based on this result, a correction factor of 0.281 is suggested for a modified sawtooth input

A classification of soybeans

Publication authorized November 7, 1929.Includes index

Korean lespedeza in Missouri

Cover title

Stable isotopes provide revised global limits of aerobic methane emissions from plants

International audienceRecently Keppler et al. (2006) discovered a surprising new source of methane ? terrestrial plants under aerobic conditions, with an estimated global production of 62?236 Tg yr?1 by an unknown mechanism. This is ~10?40% of the annual total of methane entering the modern atmosphere and ~30?100% of annual methane entering the pre-industrial (0 to 1700 AD) atmosphere. Here we test this reported global production of methane from plants against ice core records of atmospheric methane concentration (CH4) and stable carbon isotope ratios (?13CH4) over the last 2000 years. Our top-down approach determines that global plant emissions must be much lower than proposed by Keppler et al. (2006) during the last 2000 years and are likely to lie in the range 0?46 Tg yr?1 and 0?176 Tg yr?1 during the pre-industrial and modern eras, respectively

Small RNA profiling of low biomass samples: identification and removal of contaminants

Background Sequencing-based analyses of low-biomass samples are known to be prone to misinterpretation due to the potential presence of contaminating molecules derived from laboratory reagents and environments. DNA contamination has been previously reported, yet contamination with RNA is usually considered to be very unlikely due to its inherent instability. Small RNAs (sRNAs) identified in tissues and bodily fluids, such as blood plasma, have implications for physiology and pathology, and therefore the potential to act as disease biomarkers. Thus, the possibility for RNA contaminants demands careful evaluation. Results Herein, we report on the presence of small RNA (sRNA) contaminants in widely used microRNA extraction kits and propose an approach for their depletion. We sequenced sRNAs extracted from human plasma samples and detected important levels of non-human (exogenous) sequences whose source could be traced to the microRNA extraction columns through a careful qPCR-based analysis of several laboratory reagents. Furthermore, we also detected the presence of artefactual sequences related to these contaminants in a range of published datasets, thereby arguing in particular for a re-evaluation of reports suggesting the presence of exogenous RNAs of microbial and dietary origin in blood plasma. To avoid artefacts in future experiments, we also devise several protocols for the removal of contaminant RNAs, define minimal amounts of starting material for artefact-free analyses, and confirm the reduction of contaminant levels for identification of bona fide sequences using ‘ultra-clean’ extraction kits. Conclusion This is the first report on the presence of RNA molecules as contaminants in RNA extraction kits. The described protocols should be applied in the future to avoid confounding sRNA studies. Keywords: RNA sequencing; Artefact removal; Exogenous RNA in human blood plasma; Contaminant RNA; Spin column

Are lay people good at recognising the symptoms of schizophrenia?

©2013 Erritty, Wydell. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.This article has been made available through the Brunel Open Access Publishing Fund.Aim: The aim of this study was to explore the general public’s perception of schizophrenia symptoms and the need to seekhelp for symptoms. The recognition (or ‘labelling’) of schizophrenia symptoms, help-seeking behaviours and public awareness of schizophrenia have been suggested as potentially important factors relating to untreated psychosis. Method: Participants were asked to rate to what extent they believe vignettes describing classic symptoms (positive and negative) of schizophrenia indicate mental illness. They were also asked if the individuals depicted in the vignettes required help or treatment and asked to suggest what kind of help or treatment. Results: Only three positive symptoms (i.e., Hallucinatory behaviour, Unusual thought content and Suspiciousness) of schizophrenia were reasonably well perceived (above 70%) as indicating mental illness more than the other positive or negative symptoms. Even when the participants recognised that the symptoms indicated mental illness, not everyone recommended professional help. Conclusion: There may be a need to improve public awareness of schizophrenia and psychosis symptoms, particularly regarding an awareness of the importance of early intervention for psychosis