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Background: Knowledge of the location of sensor devices is crucial for many medical applications of wireless body area networks, as wearable sensors are designed to monitor vital signs of a patient while the wearer still has the freedom of movement. However, clinicians or patients can misplace the wearable sensors, thereby causing a mismatch between their physical locations and their correct target positions. An error of more than a few centimeters raises the risk of mistreating patients.Objective: The present study aims to develop a scheme to calculate and detect the position of wearable sensors without beacon nodes.Methods: A new scheme was proposed to verify the location of wearable sensors mounted on the patient's body by inferring differences in atmospheric air pressure and received signal strength indication measurements from wearable sensors. Extensive two-sample t tests were performed to validate the proposed scheme.Results: The proposed scheme could easily recognize a 30-cm horizontal body range and a 65-cm vertical body range to correctly perform sensor localization and limb identification.Conclusions: All experiments indicate that the scheme is suitable for identifying wearable sensor positions in an indoor environment. [ABSTRACT FROM AUTHOR]

It is known that neutron background is a major problem for low-background experiments carrying out underground, such as dark matter search, double-beta decay searches and other experiments known as Underground Physics. We present here some results obtained with the en-detector of 0.75 m, which is running for more than 4 years underground at a depth of 25 m water equivalent in Skobeltsyn Institute of Nuclear Physics, Moscow State University. Some spontaneous increases in thermal neutron flux up to a factor of 3 were observed in delayed anti-correlation with barometric pressure. The phenomenon can be explained by the radon barometric pumping effect resulting in similar effect in neutron flux being produced in (α, n)-reactions by alpha-decays of radon and its daughters in surrounding rock. This is the first demonstration of the barometric pumping effect observed in thermal neutron flux underground. [ABSTRACT FROM AUTHOR]

We present the results of a survey of the galactic cosmic ray (GCR) flux measured at different altitudes, from the sea level, up to ∼4600 m a.s.l. This altitude survey was carried out with a “Mini” Neutron Monitor (MNM), and performed inside a small area of the central part of Mexico (centered around the 19° N and 97° W position) where the geomagnetic cutoff rigidity is ∼7.8 GV. In particular, the latitudinal variation of the survey was less than 1°. making negligible the associated changes in the geomagnetic cutoff rigidity (∼0.4 GV). This is the first time that an altitude survey has been performed using a MNM. This survey allowed us to compute the barometric coefficient β = 0.00732 ± 0.00054 mbar - 1 and β = 0.00729 ± 0.00055 mbar - 1 when we correct our data by the differences in the cutoff rigidity. This coefficient may be used to calibrate and correct the data of other cosmic ray detectors. We show that from the sea level up to ∼4600 m the barometric coefficient is constant and does not depend on the altitude as found in previous surveys. For comparison, we also present the counting rates measured by the NM64 located at Mexico City, as well as other observations carried out to determine the stability of the MNM. [ABSTRACT FROM AUTHOR]

A piecewise regression approach was used to objectively quantify barotrauma injury thresholds in two physoclistous species, Murray cod Maccullochella peelii and silver perch Bidyanus bidyanus, following simulated infrastructure passage in a barometric chamber. The probability of injuries such as swimbladder rupture, exophthalmia and haemorrhage, and emphysema in various organs increased as the ratio between the lowest exposure pressure and the acclimation pressure (ratio of pressure change, R(NE:A)) reduced. The relationship was typically non-linear and piecewise regression was able to quantify thresholds in R(NE:A) that once exceeded resulted in a substantial increase in barotrauma injury. Thresholds differed among injury types and between species but by applying a multispecies precautionary principle, the maintenance of exposure pressures at river infrastructure above 70% of acclimation pressure ( R(NE:A) of 0·7) should protect downstream migrating juveniles of these two physoclistous species sufficiently. These findings have important implications for determining the risk posed by current infrastructures and informing the design and operation of new ones. [ABSTRACT FROM AUTHOR]

Deposition of distal tephra-fall deposits in lake systems with low watershed sediment fluxes can represent large geochemical anomalies in sediment elemental composition. We examine the persistence of compositional effects of fallout from the 7.63 kyr BP Mt. Mazama caldera-forming event and other tephra deposits in the micro-laminated abyssal sediments of Pettit Lake, central Idaho, which received ~50 kg m of Mazama tephra-fall material. Persistent post-depositional dominance of the Mazama material is reflected in elemental composition and grain size distribution and is related to lake hypsometry and the presence of a large in-lake sediment reservoir subject to remobilization. Decoupling of recycled clastic mineral material with Mazama compositional affinity from both biogenic matter and from clastic material derived from within the watershed is shown by coherence between dated primary tephras and a radiocarbon chronology. [ABSTRACT FROM AUTHOR]

The influence of barometric cycling on gas transport through complex media can be described using a double porosity model. Here vertical channels simulate the effect of cracks that pass through homogeneous regions of media. The cracks are coupled to the atmosphere and act as boundaries for the sections of homogeneous media. Convection-diffusion models are then used to simulate gas transport through the coupled system. This approach has been used to model soil aeration, subsurface movement of volatile compounds, and the migration of gases to the surface after below ground nuclear detonations. In the present work, we describe four stable numerical methods that can be used to implement the double porosity model when first-order reactions produce and consume the gaseous species of interest. We find that all four methods satisfy analytical crosschecks and agree to at least seven digits of precision. An iterative solver based on Newton's method is found to be optimal as it is easily scalable to 3-D models and to multithreaded execution. [ABSTRACT FROM AUTHOR]

In 2001, the U.S. Geological Survey began conducting scientific assessments of coastal vulnerability to potential future sea- and lake-level changes in 22 National Park Service sea- and lakeshore units. Coastal park units chosen for the assessment included a variety of geological and physical settings along the U.S. Atlantic, Pacific, Gulf of Mexico, Gulf of Alaska, Caribbean, and Great Lakes shorelines. This research is motivated by the need to understand and anticipate coastal changes caused by accelerating sea-level rise, as well as lake-level changes caused by climate change, over the next century. The goal of these assessments is to provide information that can be used to make long-term (decade to century) management decisions. Here we analyze the results of coastal vulnerability assessments for several coastal national park units. Index-based assessments quantify the likelihood that physical changes may occur based on analysis of the following variables: tidal range, ice cover, wave height, coastal slope, historical shoreline change rate, geomorphology, and historical rate of relative sea- or lake-level change. This approach seeks to combine a coastal system's susceptibility to change with its natural ability to adapt to changing environmental conditions, and it provides a measure of the system's potential vulnerability to the effects of sea- or lake-level change. Assessments for 22 park units are combined to evaluate relationships among the variables used to derive the index. Results indicate that Atlantic and Gulf of Mexico parks have the highest vulnerability rankings relative to other park regions. A principal component analysis reveals that 99% of the index variability can be explained by four variables: geomorphology, regional coastal slope, water-level change rate, and mean significant wave height. Tidal range, ice cover, and historical shoreline change are not as important when the index is evaluated at large spatial scales (thousands of kilometers). [ABSTRACT FROM AUTHOR]

The dataset from the SUPERTANK laboratory experiment was analyzed to examine wave runup and the corresponding upper limit of beach-profile change. Thirty SUPERTANK runs were investigated that included both erosional and accretionary wave conditions with random and monochromatic waves. The upper limit of beach change UL was found to approximately equal the vertical excursion of total wave runup, Rtw. An exception was runs where beach or dune scarps were produced, which substantially limit the uprush of swash motion to produce a much reduced total runup. Based on the SUPERTANK dataset, the vertical extent of wave runup above mean water level on a beach without scarp formation was found to approximately equal the significant breaking wave height, Hbs. Therefore, a new and simple relation Rtw = Hbs is proposed. The linear relationship between total runup and breaking wave height is supported by a conceptual derivation. In addition, the relation is extended to UL = Rtw = Hbs to approximate the upper limit of beach change. This formula accurately reproduced the measured upper limit of beach change from the three-dimensional experiments in the Corps' large-scale sediment transport facility. For the studied laboratory cases, predictions of wave runup were not improved by including a slope-dependent surf-similarity parameter. The limit of wave runup was substantially less for monochromatic waves than for random waves, attributed to absence of lowfrequency motion. [ABSTRACT FROM AUTHOR]

The coastline of Hai Hau District, located on the northeast coast of Vietnam with about 30 km of shoreline, is chronically eroding. Previous studies have tried to highlight the main causes of the erosion along this coastline, and several hypotheses exist. To examine the hypothesis that gradients in the longshore sediment transport rate and cross-shore fine sediment lost offshore are the main causes generating the serius erosion at Hai Hau Beach, a newly developed numerical model of shoreline change based on the one-line theory was applied and compared with data. Sea dike segments, reinforced by stones and mortar, were modeled using a seawall boundary condition, and the sediment continuity equation was modified to take into account the offshore transport of fine-grained sediment. The simulated shorelines agreed well with the measured shorelines, both for the calibration and validation periods. The calculated sediment budget shows that the net sediment transport is in the southward direction and that a large amount of finegrained sediment is lost into deep water. These two sinks of sediment are believed to be the main causes of the serious erosion at Hai Hau Beach. [ABSTRACT FROM AUTHOR]

Bathymetric data based on sounding surveys and intertidal elevations measured using Real-Time Kinematic Global Positioning System methodology were analyzed using Geographical Information System techniques to examine the morphological evolution of the tidal island Jiu Duan Sha (JDS) in the Yangtze estuary. It was found that, from 1958 to 2005, the area and sediment volume of JDS increased by 96% and 156% above the 5 m isobath and by 331% and 504% above the Lowest Astronomic Tide (LAT). Specifically, the maximum elevation of the island increased from 0.3 to 4.9 m above the LAT, and the salt marsh increased from 0% to 40% of the intertidal area. The dominant factor controlling the growth of this wetland was found to have varied with time. The growth was mainly due to the deposition of riverine sediment before the 1970s but was primarily the result of the merging of a shoal into JDS between 1971 and 1994 and, later, the local engineering projects between 1994 and 2005. It was concluded that human activities are playing an increasingly important role in the morphological evolution of tidal wetlands in the Yangtze estuary. [ABSTRACT FROM AUTHOR]

In years 2006-2007, at the area of Poland there were established a network of the absolute gravity measurements points for definition gravity reference system of the Polish Permanent GNSS network and geodynamic networks. Lower Silesian part of the system consist of five points situated in places: Wrocław, Kłodzko, Janowice Wielkie, Lubiąż i Świebodzice. The paper contain detailed description of location of the points Wrocław, Kłodzko, Janowice and Lubiąż, methods of monumentation and first results of measurements made at the points. [ABSTRACT FROM AUTHOR]

A common mistake in introductory physics textbooks is the omission of the buoyant force exerted by the air on an object floating in a liquid. One previous work (Lan 2000 Phys. Teach.38 125) includes that missing term but assumes that the air, like the liquid, is incompressible. Here we account for the barometric variation in the density of air with altitude. Although the numerical size of that correction is small, it is conceptually important because it helps students better appreciate that buoyancy results from the variation in fluid pressure across the surface of an object. [ABSTRACT FROM AUTHOR]

The article profiles Colombian military engineer Francisco Jose de Caldas and mentions his education and achievements in astronomy, zoology, and military science as well as discusses his use of thermal hypsometry to measure the barometric altitude of mountains.