Underwater optical wireless communications : depth dependent variations in attenuation

Depth variations in the attenuation coefficient for light in the ocean were calculated using a one-parameter model based on the chlorophyll-a concentration Cc and experimentally-determined Gaussian chlorophyll-depth profiles. The depth profiles were related to surface chlorophyll levels for the range 0–4  mg/m2, representing clear, open ocean. The depth where Cc became negligible was calculated to be shallower for places of high surface chlorophyll; 111.5 m for surface chlorophyll 0.8<Cc<2.2  mg/m3 compared with 415.5 m for surface Cc<0.04  mg/m3. Below this depth is the absolute minimum attenuation for underwater ocean communication links, calculated to be 0.0092  m−1 at a wavelength of 430 nm. By combining this with satellite surface-chlorophyll data, it is possible to quantify the attenuation between any two locations in the ocean, with applications for low-noise or secure underwater communications and vertical links from the ocean surface

Therapeutic Potential of Haptic TheraDrive: An Affordable Robot/Computer System for Motivating Stroke Rehabilitation

There is a need for increased opportunities for effective neurorehabilitation services for stroke survivors outside the hospital environment. Efforts to develop low-cost robot/computer therapy solutions able to be deployed in home and community rehabilitation settings have been growing. Our long-term goal is to develop a very low-cost system for stroke rehabilitation that can use commercial gaming technology and support rehabilitation with stroke survivors at all functioning levels. This paper reports the results of experiments comparing the old and new TheraDrive systems in terms of ability to assist/resist subjects and the root-mean-square (RMS) trajectory tracking error. Data demonstrate that the new system, in comparison to the original TheraDrive, produces a larger change in normalized trajectory tracking error when assistance/resistance is added to exercises and has the potential to support stroke survivors at all functioning levels

Design and Development of an Affordable Haptic Robot with Force-Feedback and Compliant Actuation to Improve Therapy for Patients with Severe Hemiparesis

The study describes the design and development of a single degree-of-freedom haptic robot, Haptic Theradrive, for post-stroke arm rehabilitation for in-home and clinical use. The robot overcomes many of the weaknesses of its predecessor, the TheraDrive system, that used a Logitech steering wheel as the haptic interface for rehabilitation. Although the original TheraDrive system showed success in a pilot study, its wheel was not able to withstand the rigors of use. A new haptic robot was developed that functions as a drop-in replacement for the Logitech wheel. The new robot can apply larger forces in interacting with the patient, thereby extending the functionality of the system to accommodate low-functioning patients. A new software suite offers appreciably more options for tailored and tuned rehabilitation therapies. In addition to describing the design of the hardware and software, the paper presents the results of simulation and experimental case studies examining the system\u27s performance and usability

Public health implications of colombian diaspora : market density as an indicator for food insecurities.

Food security is outlined as the universal capacity to procure safe food goods in a diurnal modus consistent with biological load and lifestyle. Therefore, food insecurity is the failure of these processes, which can predictably lead to anthropometric deviations, reduced educational attainment, and other deleterious public health disruptions. It is thereby crucial to reveal novel approaches in predicting food insecurities, and to elucidate if subsisting mechanisms either frustrate or fortify these conditions. Colombia is a developing country suffering from an internal conflict that has displaced over 5.2 million residents. This humanitarian crisis characteristically exacerbates established food insecurities, which extends over 41% of the total population, or 19.2 million inhabitants. Hencetofore, no study has attempted to couple market distribution to the reported food security status of Bogota� D.C., a megalopolis of 8.7 million residents, of which, more than 5.8 million remain currently food insecure. It was then hypothesized that market density could reliably infer sustenance anxieties athwart the 20 localities of Bogota�. Our results revealed an orthogonal relationship between market distribution and varying levels of food insecurities throughout Bogota�, foisting poverty as a primary antecedent to hunger

GraFIX: a semiautomatic approach for parsing low- and high-quality eye-tracking data

Fixation durations (FD) have been used widely as a measurement of information processing and attention. However, issues like data quality can seriously influence the accuracy of the fixation detection methods and, thus, affect the validity of our results (Holmqvist, Nyström, & Mulvey, 2012). This is crucial when studying special populations such as infants, where common issues with testing (e.g., high degree of movement, unreliable eye detection, low spatial precision) result in highly variable data quality and render existing FD detection approaches highly time consuming (hand-coding) or imprecise (automatic detection). To address this problem, we present GraFIX, a novel semiautomatic method consisting of a two-step process in which eye-tracking data is initially parsed by using velocity-based algorithms whose input parameters are adapted by the user and then manipulated using the graphical interface, allowing accurate and rapid adjustments of the algorithms’ outcome. The present algorithms (1) smooth the raw data, (2) interpolate missing data points, and (3) apply a number of criteria to automatically evaluate and remove artifactual fixations. The input parameters (e.g., velocity threshold, interpolation latency) can be easily manually adapted to fit each participant. Furthermore, the present application includes visualization tools that facilitate the manual coding of fixations. We assessed this method by performing an intercoder reliability analysis in two groups of infants presenting low- and high-quality data and compared it with previous methods. Results revealed that our two-step approach with adaptable FD detection criteria gives rise to more reliable and stable measures in low- and high-quality data

Forests in Flux: The Effects of Demographic Change on Forest Cover in New England and New York

This brief contributes to a better understanding of the linkages between demographic and forest cover change so as to inform policy efforts aimed at maintaining existing forested areas in and around sprawling urban centers. Authors Mark Ducey, Kenneth Johnson, Ethan Belair, and Miranda Mockrin report that forest cover has declined throughout New England and New York over the last decade. In rural areas, forest loss is primarily due to commercial timber harvesting and represents a temporary change. Conversely, forest cover decline in urban areas is usually the result of development and is likely to be permanent. Forest cover change is strongly linked to demographic variables throughout this region. Forest cover loss is most pronounced along the urban fringe, where population growth is greatest. Amenity-rich rural areas are also experiencing high rates of population growth and regionally-high rates of forest cover loss. However, the causes of forest cover change in these areas are less certain. Forest cover change has the potential to impact ecosystem services important to both local residents and the larger region

Missing in Action? Electronic Gaming Machines in Gambling Studies Research

In the past thirty years casinos across the world have become dominated by the rise of “electronic gaming machines” (EGMs). Expanding with tremendous speed, this technology has arguably become the dominant form of non-online gambling around the world at time of writing (DeMichele, 2017; Schwartz, 2018). EGMs are also noted as being one of the most harmful forms of gambling, with significant numbers of players betting beyond their financial limits (MacLaren et al, 2012; Stewart & Wohl, 2013), spending a disproportionate amount of time playing (Cummings, 1999; Ballon, 2005; Schüll, 2012; cf. Dickerson, 1996), becoming disconnected from the world outside of the “zone” (Schüll, 2012) of gambling play, and even becoming bankrupt or otherwise financially crippled as a result of their use (Petry, 2003; Scarf et al, 2011). Using metadata from Web of Science and Scopus databases, we analysed peer-reviewed gambling research produced in Australia, New Zealand, North America and the UK published between 1996 and 2016. Surprisingly, we found that the overwhelming of majority of articles do not specifically address EGMs as the most popular and pervasive gambling technology available. Our paper teases out some concerning implications of this finding for the interdisciplinary field of gambling studies

A Phylogenetic Classification of Polemoniaceae

Three hundred seventy nine species of Polemoniaceae are arranged in a phylogenetic classification composed of three subfamilies, eight tribes, and 26 genera. Nomenclature of one tribe is clarified and the circumscription of several tribes differs greatly from previous classifications. Five new genera, Bryantiella, Dayia, Lathrocasis, Microgilia, and Saltugilia, are proposed. In addition, four new species are described from the genera Allophyllum, Dayia, Giliastrum, and lpomopsis. This treatment represents a major reclassification with 59 new combinations, and the application of several additional combinations not used in recent years