Why is Water so Efficient at Suppressing the Effects of Explosions?

When most experienced explosives engineers first observe an explosion suppressed by bags of water, they are convinced that there has been a misfire. Depending on the amount of water and the way it is contained, the overpressure can be reduced by a factor of ten, sometimes more than twenty. The number of fragments from shell cases can be one hundred times less. Their velocities can be seven times. Slugs from focal point charges are stopped. Safety distances around magazines can be cut. The number of people evacuated from a bomb disposal site can be reduced. In June 1999, engineers from 33 Regiment (Explosive Ordnance Disposal) saved an entire village in Kosovo from the detonation of a 2,000-pound NATO bomb by using water bags

Bench-to-bedside review: The value of cardiac biomarkers in the intensive care patient

The use of cardiac biomarkers in the intensive care setting is gaining increasing popularity. There are several reasons for this increase: there is now the facility for point-of-care biomarker measurement providing a rapid diagnosis; biomarkers can be used as prognostic tools; biomarkers can be used to guide therapy; and, compared with other methods such as echocardiography, the assays are easier and much more affordable. Two important characteristics of the ideal biomarker are disease specificity and a linear relationship between the serum concentration and disease severity. These characteristics are not present, however, in the majority of biomarkers for cardiac dysfunction currently available. Those clinically useful cardiac biomarkers, which naturally received the most attention, such as troponins and B-type natriuretic peptide, are not as specific as was originally thought. In the intensive care setting, it is important for the user to understand the degree of specificity of these biomarkers and that the interpretation of the results should always be guided by other clinical information. The present review summarizes the available biomarkers for different cardiac conditions. Potential biomarkers under evaluation are also briefly discussed

The increasingly global scope of the foreign corrupt practices act

El presente artículo analiza el desarrollo, las características y el alcance de la Ley de Prácticas Corruptas en el Exterior de los Estados Unidos y sus implicaciones en los actos ilegales en las organizaciones públicas y privadas estadounidenses y del resto del mundo, en el marco de un contexto de cooperación internacional, índices bursátiles y relaciones económicas globales. Se exponen diferentes casos y formas de actuar legal e ilegalmente en algunas organizaciones a partir de la normatividad analizada. El documento tiene un alto valor contextual para resaltar el papel de la contabilidad como soporte de actos ilegales y advierte sobre las implicaciones de actuar fraudulentamente cuando hay relaciones comerciales con empresas estadounidenses cubiertas con esta ley.This article analyzes the development, characteristics and scope of the Foreign Corrupt Practices Act of the United States and its implications for illegal acts in public and private organizations in the United States and the rest of the world, within the framework of a context of international cooperation, stock market indices and global economic relations. Different cases and ways of acting legally and illegally in some organizations are exposed based on the regulations analyzed. The document has a high contextual value to highlight the paper of accounting as a support for illegal acts and warns about the implications of acting fraudulently when there are business relationships with US companies covered by this law

Absorbing wave makers and wide tanks

Experiments aimed at generating power from sea waves used models which sometimes reflected waves back to the wave-maker. The difficulty was avoided by changing the wave-maker control system so that it could absorb reflections. A wide tank using a bank of absorbing wave-makers is being used to test more advanced models in seas of controlled angular spread. A crude measure of crest-length can be obtained from measurement of the correlation coefficients between wave-gauges at different separations

Power conversion systems for Ducks

This paper tries to define the problems of power conversion for a wave power device . It presents a little of the background theory; it discusses design principles, existing components and modifications to them; it tries to identify the main practical difficulties. Finally, it describes four possible solutions

Light from the Face of the Deep?

Description of the development of the Duck in the University of Edinburgh Bulletin

Blurring Group Boundaries: The Impact of Subgroup Threats on Global Citizenship

We examined the outcomes of an extinction threat (possible discontinuation of a group’s symbolic or actual existence) to one’s nation on global citizenship identification and related prosocial values. In Study 1, participants showed a drop in global citizenship identification when America was threatened (vs. absence of threat). In Study 2, participants reported lower global citizenship identification when America was threatened (vs. absence of threat) and the perception that one’s normative environment did not support a global citizen identity mediated the relationship between threat and identification. Furthermore, the threat was shown to indirectly predict lower endorsement for prosocial values and behaviors (e.g., intergroup empathy and helping). Together, the results highlight threats to subgroups as a potential barrier to viewing oneself as a global citizen

Alternative approaches to trend estimation.

This thesis suggests a general approach for estimating the trend of a univariate time series. It begins by suggesting and defining a set of "desirable" trend properties, namely "Fidelity", "Smoothness", "Invariance" and "Additivity", which are then incorporated into the design of an appropriate non-stationary time series model.The unknown parameters of the model are then estimated using a wide selection of "optimal" procedures, each parameter having at least two such procedures applied to it. Attention is paid to the development of algorithms to implement the procedures in practice.The model is gradually extended from a basic, non-seasonal model consisting of a simple lagged trend to a general, seasonal model incorporating a variable parameter, general autoregressive trend

Modal phase modulators based on liquid crystals with 3D-printed polymer microstructures: increasing size and complexity

We present extended capabilities in simple liquid crystal-based devices that are applicable to adaptive optics and other related fields requiring wavefront manipulation. The laser-written devices can provide complex phase profiles, but are extremely simple to operate, requiring only a single electrode pair tuned between 0 and 10 V RMS. Furthermore, the devices operate in the transmissive mode for easy integration into the optical path. We present here as examples three such devices: the first device reproduces the defocus Zernike polynomial; the second device reproduces a seventh-order Zernike polynomial, tertiary coma; and the last example is of a primary spherical aberration. All devices offer wavelength-scale wavefront manipulation up to more than 2π radians peak-to-peak phase at a wavelength of 660 nm. The coma correction device is significantly more complex, reproducing a mode two orders higher than previous demonstrations, while the spherical device is nearly a full order of magnitude larger, measuring 2 mm in diameter