Cantilever-based Resonant Gas Sensors with Integrated Recesses for Localized Sensing Layer Deposition

This work presents mass-sensitive hammerhead resonators with integrated recesses as a gas-phase chemical microsensor platform. Recesses are etched into the head region of the resonator to locally deposit chemically sensitive polymers by ink-jet printing. This permits the sensing films to be confined to areas that (a) are most effective in detecting mass loading and (b) are not strained during the in-plane vibrations of the resonator. As a result of the second point, even 5-μm thick polymer coatings on resonators with a 9-12 μm silicon thickness barely affect the Q-factor in air. This translates into higher frequency stability and ultimately higher sensor resolution compared to uniformly coated devices

Überinfusion von Verbrennungsopfern: häufig und schädlich

Zusammenfassung: Hintergrund: Schwerbrandverletzte (mehr als 20% verbrannter Körperoberfläche bei Erwachsenen) weisen in der ersten Phase (8-48h) einen durch das massive Kapillarleck bedingten Verbrennungsschock auf, der einer Infusionstherapie bedarf, um die Hämodynamik wieder herzustellen. Bis in die 80erJahre stellte eine unzureichende Flüssigkeitstherapie (Unterinfusion) die Haupttodesursache von Verbrennungspatienten dar. Seither ist die übermäßige Flüssigkeitstherapie (Überinfusion) zu einer beachtenswerten Quelle von Komplikationen geworden: abdominales Kompartmentsyndrom, Entlastungsschnitte (Escharotomie), Verschlechterung des Gasaustauschs, Verlängerung der künstlichen Beatmung und des Spitalaufenthalts. Die Überinfusion hat Ende der 90erJahre begonnen, wo innerhalb der ersten 24h Flüssigkeitsmengen zugeführt wurden, die weit über den 4ml/kg/%BSA ("burn surface area") der Parkland-Formel lagen. Ziel: Dieser Beitrag analysiert die Faktoren, welche zu einer Überinfusion führen können und zeigt Möglichkeiten, dem durch eine strikte Kontrolle der präklinischen Infusionstherapie sowie durch eine permissive Hypovolämie vorzubeuge

A 100-Year Sediment Budget for Chesapeake Bay

Chesapeake Bay is a depositional basin that is filling from both ends and the sides. During the century ended in the mid-1950s between 1.0 x 109 and 2.92 x 109 metric tons of sediment accumulated in the bay. The bay\u27s largest tributary, the Susquehanna River, is a major source of fine-grained sediments; its coarser load being trapped by dams. The continental shelf is the largest single source of sediment for the basin. A massive quantity of sand, perhaps as much of forty percent of the net deposition, enters the bay between the Virginia capes and works its way tens of kilometers upstream, potentially as far north as Tangier Island, near the Virginia-Maryland boundary. Other sources of sediment are shoreline erosion, biogenic production, preHolocene outcrops, and the other tributaries. These tributary estuaries do provide coarse sediment to the bay through longshore transport and bedload movement in the nearshore.shallows and, perhaps, in the channel bottom. The contribution of suspended or fine-grained sediment by the tributary estuaries is unknown. Indeed they may be sinks and not sources. \u27The contribution of the tributary estuaries and the quantification of the bay-mouth sand-source and uncertainties associated with the bathymetric comparisons in the determination of the net mass of sediment deposition, make it difficult to balance a sediment budget for Chesapeake Bay. Most of the imbalance is in the sand fraction within the Virginia portion of the system; with far more sand being deposited than can be accounted for by the independently quantifiable sources. Not considering the continental shelf as a source of sand, the budget fails to balance by a factor of between 2.7 and 7.6. Making certain assumptions about the quantity of sanQ entering the bay through its mouth (the continental shelf source), the difference can be sufficiently reduced that the budget more nearly balances

Propagation of gamma rays and production of free electrons in air

A new concept of remote detection of concealed radioactive materials has been recently proposed \cite{Gr.Nusin.2010}-\cite{NusinSprangle}. It is based on the breakdown in air at the focal point of a high-power beam of electromagnetic waves produced by a THz gyrotron. To initiate the avalanche breakdown, seed free electrons should be present in this focal region during the electromagnetic pulse. This paper is devoted to the analysis of production of free electrons by gamma rays leaking from radioactive materials. Within a hundred meters from the radiation source, the fluctuating free electrons appear with the rate that may exceed significantly the natural background ionization rate. During the gyrotron pulse of about 10 microsecond length, such electrons may seed the electric breakdown and create sufficiently dense plasma at the focal region to be detected as an unambiguous effect of the concealed radioactive material.Comment: 27 pages, 10 figure

Lp-cohomology of negatively curved manifolds

We compute the $L^p$-cohomology spaces of some negatively curved manifolds. We deal with two cases: manifolds with finite volume and sufficiently pinched negative curvature, and conformally compact manifolds

Dynamics of light propagation in spatiotemporal dielectric structures

Propagation, transmission and reflection properties of linearly polarized plane waves and arbitrarily short electromagnetic pulses in one-dimensional dispersionless dielectric media possessing an arbitrary space-time dependence of the refractive index are studied by using a two-component, highly symmetric version of Maxwell's equations. The use of any slow varying amplitude approximation is avoided. Transfer matrices of sharp nonstationary interfaces are calculated explicitly, together with the amplitudes of all secondary waves produced in the scattering. Time-varying multilayer structures and spatiotemporal lenses in various configurations are investigated analytically and numerically in a unified approach. Several new effects are reported, such as pulse compression, broadening and spectral manipulation of pulses by a spatiotemporal lens, and the closure of the forbidden frequency gaps with the subsequent opening of wavenumber bandgaps in a generalized Bragg reflector

Using a value chain framework for food safety assessment of broiler and indigenous chicken meat systems of Nairobi

Purpose: Research on livestock food systems in developing countries remains limited, yet this context needs to be understood to investigate the epidemiology of zoonoses. The aim of this study was to use a value chain framework to characterize the broiler and indigenous chicken meat systems of Nairobi and their food safety risks. Methods: Using such a framework for food safety characterisation at system level is novel and has significant potential in developing countries. Data collection involved 18 focus group discussions and 236 interviews with various poultry meat value chain stakeholders in Nairobi. Analysis included chain mapping and identification of governance and food safety challenges. Results: The study identified 10 chain profiles, characterising the broiler and indigenous chicken systems, and production-retailing continuum. Food safety risks identified were related to lack of biosecurity, cold chain and access to water, poor cleaning and hygiene practices, consumption of sick animals, significant environmental contamination of by-products, and lack of inspection at farm slaughter. Large companies dominated the governance of the broiler system through the control of day-old chick production. Overall government control was relatively weak leading to minimal official regulatory enforcement. Large companies and brokers were identified as dominant groups in market information dissemination and price setting. No dominant group was identified for indigenous chicken profiles, farming being at household level for local consumption, with quasi non-existent regulations. Lack of industry association was system-wide, creating a barrier for access to capital. Other system barriers included lack of space and expertise, leading to poor infrastructure and limited ability to implement effective hygienic measures. Conclusions and relevance: Optimal food safety and disease control strategies should consider the structure of the poultry meat system and stakeholder interactions to ensure effective programmes. This study provides a new perspective for epidemiologists and public health officers to address food safety risks in full understanding of the food system context