Interpretation of oceanic magnetic anomalies using a linear inverse technique

A direct magnetic interpretational technique has been developed and applied to oceanic magnetic anomalies. The method of interpretation computes a distribution of magnetization, within a specified two-dimensional model - given the direction of magnetization, from the observed magnetic anomalies. The technique is based on the numerical solution of a linear integral equation which is approximated by a finite set of linear algebraic equations. These equations relate (n) observed magnetic anomaly field points to (m) unknown magnetization values. Solution of this system of equations is carried out by computer, using matrix operations. The programming procedure allows model elements of irregular cross-section to be incorporated within the magnetic layer and provides a solution to both the completely determined and overdetermined problem (i.e. n≥m). Details of this procedure are presented together with an evaluation of methods of application. Interpretations of magnetic profiles in the North Atlantic Ocean, the Gulf of Aden and the Pacific Ocean are presented in terms of computed distributions of magnetization confined to Layer 2. Results are discussed in terms of the Vine-Matthews hypothesis of sea-floor spreading and certain apparent differences in the bulk magnetization of the oceanic crust. Model studies confirm the feasibility of a thin magnetic layer (0.5 km), situated just below the sea-floor. The approximate shape of this magnetic layer is deduced from known magnetization values obtained from dredged rock samples. Interpretation of magnetic data from the Pacific Ocean indicates that both vertical and inclined source bodies, within Layer 2, represent plausible models, although extensive subhorizontal bodies (dipping at 10 and less) are unlikely

Policy Response to Pandemic Influenza: The Value of Collective Action

This paper examines positive externalities and complementarities between countries in the use of antiviral pharmaceuticals to mitigate pandemic influenza. It demonstrates the presence of treatment externalities in simple SIR (susceptible-infectious-recovered) models and simulations of a Global Epidemiological Model. In these simulations, the pandemic spreads from city to city through the international airline network and from cities to rural areas through ground transport. While most treatment benefits are private, spillovers suggest that it is in the self-interest of high-income countries to pay for some antiviral treatment in low-income countries. The most cost-effective policy is to donate doses to the country where the outbreak originates; however, donating doses to low-income countries in proportion to their populations may also be cost-effective. These results depend on the transmissibility of the flu strain, its start date, the efficacy of antivirals in reducing transmissibility, and the proportion of infectious people who can be identified and treated.pandemic influenza, disease control externalities

Challenges in Upgrading Emergency Power in Florida Nursing Homes Following Hurricane Irma

Maintaining and restoring electricity after a disaster helps to preserve the health and well-being of the elderly who are at increased risk of heat stress and may be dependent upon life-sustaining medical equipment. Mitigation policies altered in reaction to increased public interest without thorough consideration of industry-specific resources may contribute to delays in implementation and unrealized potential for emergency power coverage within individual facilities. The objectives of this research are twofold: (i) to examine the relationship between preexisting conditions of life-safety systems at facilities and date of implementation of emergency power regulation improvements and (ii) to assess the role of interagency connections—such as emergency management, fire safety, health care administration, and electricity providers—in facilitating compliance with safety regulations. A case study regarding the capacity to implement new emergency power regulations was conducted in Florida with 12 nursing homes affected by Hurricane Irma. The proposals to maintain temperatures and life-sustaining equipment under the updated regulations were not consistent among nursing homes within each county or between counties. Facilities with no preexisting life-safety violations were among the first to comply with new emergency power regulations. Those with prior violations often utilized procedural updates and external resources to comply. Nursing facilities that required additional support for remediation prior to the storm had plans approved earlier or without a second review as compared with those relying on internal resources. These results establish a baseline for the conditions associated with timely compliance including the importance of collective agency to mitigate risk

Rae and the Tradition of Scottish Political Economy

The purpose of the chapter is to investigate how far Rae is representative of the Scottish Political Economy Tradition, where tradition is understood in terms of continuity in a shared approach, allowing for theoretical differences. While Rae conforms to most features identified with the Scottish tradition, his opposition to Smith’s methodology suggests a divergence of approach which would put him outside the tradition. It is argued here that this divergence applies only to Rae’s professed methodology, not to his practice

Traditions in thought: The case of Scottish political economy

A number of commentators have recently identified a 'uniquely Scottish mode of thought in economics', or a particular 'Scottish political economy tradition'. In this paper the concept of tradition, defined as those features common to practitioners over a relatively long period, is investigated in relation to 'school', 'paradigm' and 'research programme'. An application of the concept to the Scottish Enlightenment period suggests that its use is in line with the philosophical approach of Adam Smith, and shows that the concept allows account to be taken of external institutional/historical influences in interpreting the history of economics

Recovery of nickel and cobalt from nitrate-based nickel laterite leach solutions using direct solvent extraction

A direct solvent extraction system was developed to recover nickel and cobalt from nitrate-based nickel laterite liquors, as opposed to traditional sulphate-based liquors. The development and optimisation of promising solvent systems is reported, along with a comparison of three potential options to inform recommendations for commercial applications. Finally, an investigation into the chemical stability of the solvent extraction reagents is detailed to determine if a nitrate-based process affected reagent stability compared to a sulphate-based process

Progranulin in frontotemporal lobar degeneration and neuroinflammation

Progranulin (PGRN) is a pleiotropic protein that has gained the attention of the neuroscience community with recent discoveries of mutations in the gene for PGRN that cause frontotemporal lobar degeneration (FTLD). Pathogenic mutations in PGRN result in null alleles, and the disease is likely the result of haploinsufficiency. Little is known about the normal function of PGRN in the central nervous system apart from a role in brain development. It is expressed by microglia and neurons. In the periphery, PGRN is involved in wound repair and inflammation. High PGRN expression has been associated with more aggressive growth of various tumors. The properties of full length PGRN are distinct from those of proteolytically derived peptides, referred to as granulins (GRNs). While PGRN has trophic properties, GRNs are more akin to inflammatory mediators such as cytokines. Loss of the neurotrophic properties of PGRN may play a role in selective neuronal degeneration in FTLD, but neuroinflammation may also be important. Gene expression studies suggest that PGRN is up-regulated in a variety of neuroinflammatory conditions, and increased PGRN expression by microglia may play a pivotal role in the response to brain injury, neuroinflammation and neurodegeneration

Visual exploration in Parkinson's disease and Parkinson's disease dementia

Parkinson's disease, typically thought of as a movement disorder, is increasingly recognized as causing cognitive impairment and dementia. Eye movement abnormalities are also described, including impairment of rapid eye movements (saccades) and the fixations interspersed between them. Such movements are under the influence of cortical and subcortical networks commonly targeted by the neurodegeneration seen in Parkinson's disease and, as such, may provide a marker for cognitive decline. This study examined the error rates and visual exploration strategies of subjects with Parkinson's disease, with and without cognitive impairment, whilst performing a battery of visuo-cognitive tasks. Error rates were significantly higher in those Parkinson's disease groups with either mild cognitive impairment (P = 0.001) or dementia (P < 0.001), than in cognitively normal subjects with Parkinson's disease. When compared with cognitively normal subjects with Parkinson's disease, exploration strategy, as measured by a number of eye tracking variables, was least efficient in the dementia group but was also affected in those subjects with Parkinson's disease with mild cognitive impairment. When compared with control subjects and cognitively normal subjects with Parkinson's disease, saccade amplitudes were significantly reduced in the groups with mild cognitive impairment or dementia. Fixation duration was longer in all Parkinson's disease groups compared with healthy control subjects but was longest for cognitively impaired Parkinson's disease groups. The strongest predictor of average fixation duration was disease severity. Analysing only data from the most complex task, with the highest error rates, both cognitive impairment and disease severity contributed to a predictive model for fixation duration [F(2,76) = 12.52, P ≤ 0.001], but medication dose did not (r = 0.18, n = 78, P = 0.098, not significant). This study highlights the potential use of exploration strategy measures as a marker of cognitive decline in Parkinson's disease and reveals the efficiency by which fixations and saccades are deployed in the build-up to a cognitive response, rather than merely focusing on the outcome itself. The prolongation of fixation duration, present to a small but significant degree even in cognitively normal subjects with Parkinson's disease, suggests a disease-specific impact on the networks directing visual exploration, although the study also highlights the multi-factorial nature of changes in exploration and the significant impact of cognitive decline on efficiency of visual searc