A multiparameter wearable physiologic monitoring system for space and terrestrial applications.

A novel, unobtrusive and wearable, multiparameter ambulatory physiologic monitoring system for space and terrestrial applications, termed LifeGuard, is presented. The core element is a wearable monitor, the crew physiologic observation device (CPOD), that provides the capability to continuously record two standard electrocardiogram leads, respiration rate via impedance plethysmography, heart rate, hemoglobin oxygen saturation, ambient or body temperature, three axes of acceleration, and blood pressure. These parameters can be digitally recorded with high fidelity over a 9-h period with precise time stamps and user-defined event markers. Data can be continuously streamed to a base station using a built-in Bluetooth RF link or stored in 32 MB of on-board flash memory and downloaded to a personal computer using a serial port. The device is powered by two AAA batteries. The design, laboratory, and field testing of the wearable monitors are described.     

Fluorescence tracking of dissolved and particulate organic matter quality in a river-dominated estuary

Excitation-emission matrix (EEM) fluorescence was combined with parallel factor analysis (PARAFAC) to model base-extracted particulate (POM) and dissolved (DOM) organic matter quality in the Neuse River Estuary (NRE), North Carolina, before and after passage of Hurricane Irene in August 2011. Principle components analysis was used to determine that four of the PARAFAC components (C1-C3 and C6) were terrestrial sources to the NRE. One component (C4), prevalent in DOM of nutrient-impacted streams and estuaries and produced in phytoplankton cultures, was enriched in the POM and in surface sediment pore water DOM. One component (C5) was related to recent autochthonous production. Photoexposure of unfiltered Neuse River water caused an increase in slope ratio values (S(R)) which corresponded to an increase in the ratio C2:C3 for DOM, and the production of C4 fluorescence in both POM and DOM. Changes to the relative abundance of C4 in POM and DOM indicated that advection of pore water DOM from surface sediments into overlying waters could increase the autochthonous quality of DOM in shallow microtidal estuaries. Modeling POM and DOM simultaneously with PARAFAC is an informative technique that is applicable to assessments of estuarine water quality.     

Efficient shift detection using multivariate exponentially-weighted moving average control charts and principal components

This paper demonstrates the use of principal components in conjunction with the multivariate exponentially-weighted moving average (MEWMA) control procedure for process monitoring. It is demonstrated that the number of variables to be monitored is reduced through this approach, and that the average run length to detect process shifts or upsets is substantially reduced as well. The performance of the MEWMA applied to all the variables may be related to the MEWMA control chart that uses principal components through the non-centrality parameter. An average run length table demonstrates the advantages of the principal components MEWMA over the procedure that uses all of the variables. An illustrative example is provided.     

Short-run statistical process control: Q-Chart enhancements and alternative methods

The first two tables in Reference 1 are incorrect. Corrected tables are provided below. The errors do not affect the conclusions or the discussion in that paper.     

A survey of singular curves in sub-Riemannian geometry

Sub-Riemannian geometry is the geometry of a distribution ofk-planes on an-dimensional manifold with a smoothly varying inner product on thek-planes. Singular curves are singularities of the space of paths tangent to the distribution and joining two fixed points. This survey is devoted to the singular curves, which can be length minimizing geodesics, independent of the choice of inner product.     

Children's use of looking behavior as a cue to detect another's goal

Three studies examined children's understanding of the role that looking behavior plays in revealing another's desired goal. In each study, participants were asked which of 2 objects a protagonist wanted to obtain. Four-year-olds did not infer that an object examined via prolonged looking was more likely to be the protagonist's goal than an object that was either glanced at or inadvertently touched. Instead, they were accurate only when the protagonist looked at one of two potential goals. In contrast, the majority of 6-year-olds (and adults in Experiment 1) consistently regarded prolonged looking as the more important cue of the protagonist's goal. These age differences suggest that development is characterized by an increasing appreciation that goal is revealed by comparative differences in the quality of perceptual connectedness to objects in the world. One explanation for these age differences is that preschoolers are limited in their understanding of the difference between perceiving with full attention and without it.     

Homeless youth and their exposure to and involvement in violence while living on the streets

Sick building syndrome is the term given to a heterogeneous constellation of symptoms that affects workers in modern mechanically ventilated office buildings. Although the cause is unknown, there is evidence that the local environment of the work station is an important determinant of symptoms. In this study, investigators examined the effect of a new, individually controlled ventilation system on workers' symptoms. Investigators studied two groups of workers in one mechanically ventilated office building: (1) a control group at whose worksite no intervention was made and (2) an intervention group. The intervention consisted of installation of a device that allowed each worker control over the ventilation supplied to his or her worksite. Just before, and 4 and 16 mo after installation of this device, workers completed self-administered questionnaires regarding occurrence of symptoms. The new ventilation system resulted in higher air velocities, more variable temperatures, and higher concentrations of airborne dust and fungal spores. Four months after installation, workers with the new ventilation system reported fewer symptoms that were (a) work-related (p < .05) and that were work-related and frequent (p < .05); in addition, they reported fewer symptoms that reduced their capacity to work (p < .01). Sixteen months after installation, workers with the new device reported fewer symptoms than at baseline (although not as significantly), and they indicated that the indoor air quality improved their productivity by 11%, compared with a 4% reduction of productivity among the control group of workers (p < .001). Investigators concluded that the new ventilation system, which provided the workers with individual control over ventilation, was associated with important and sustained reduction in symptoms.     

Impact of Relative Humidity on HVAC Filters Loaded with Hygroscopic and Non-Hygroscopic Particles

The key characteristics of an air filter—flow resistance and filtration efficiency—are strongly affected by captured particles. The impact of exposing loaded heating, ventilating, and air conditioning air filters to a relative humidity (RH) other than that experienced during loading is investigated to develop an understanding of the role of RH throughout filter operation. Flat sheets of commercial filter media were loaded with hygroscopic, non-hygroscopic, or a mixture of particles in a laboratory apparatus. When filters loaded with hygroscopic particles in dry air were exposed to an elevated RH of 40%, the flow resistance reduced by up to 47%, depending on the filter being tested. Investigation of filter efficiency before and after changes in RH in the same samples shows reductions of up to 11 percentage points in the 130-nm size range. Further increasing RH causes additional drops in flow resistance and efficiency whereas reverting back to a lower humidity does not change the filter characteristics. The irreversibility of the particle-loaded filter characteristics implies that the RH increases are associated with an irreversible change in the particle structure. The response to humidity was reduced if an aerosol mixture of hygroscopic and non-hygroscopic particles is used. Exposure of filters loaded with only non-hygroscopic particles does not show the same dependence on RH. Small increases in growth factor for RH changes below deliquescence, causing morphological changes in captured particle aggregates, is a potential explanation for the changes observed.

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