Reliability of Sleep Measures from Four Personal Health Monitoring Devices Compared to Research-Based Actigraphy and Polysomnography

Polysomnography (PSG) is the “gold standard” for monitoring sleep. Alternatives to PSG are of interest for clinical, research, and personal use. Wrist-worn actigraph devices have been utilized in research settings for measures of sleep for over two decades. Whether sleep measures from commercially available devices are similarly valid is unknown. We sought to determine the validity of five wearable devices: Basis Health Tracker, Misfit Shine, Fitbit Flex, Withings Pulse O2, and a research-based actigraph, Actiwatch Spectrum. We used Wilcoxon Signed Rank tests to assess differences between devices relative to PSG and correlational analysis to assess the strength of the relationship. Data loss was greatest for Fitbit and Misfit. For all devices, we found no difference and strong correlation of total sleep time with PSG. Sleep efficiency differed from PSG for Withings, Misfit, Fitbit, and Basis, while Actiwatch mean values did not differ from that of PSG. Only mean values of sleep efficiency (time asleep/time in bed) from Actiwatch correlated with PSG, yet this correlation was weak. Light sleep time differed from PSG (nREM1 + nREM2) for all devices. Measures of Deep sleep time did not differ from PSG (SWS + REM) for Basis. These results reveal the current strengths and limitations in sleep estimates produced by personal health monitoring devices and point to a need for future development

Assessing the long-term sequelae of mild traumatic brain injury

A mild traumatic brain injury (mTBI), also known as a concussion, is defined as an injury that results in an alteration of consciousness or mental status. Previous studies have shown mTBI populations experience a number of chronic (\u3e 1 year) symptoms, such as sleep disturbances (e.g., sleep stage alterations), mood alterations (e.g., depressive symptoms), and cognitive alterations (e.g., poor concentration). The three chapters of this dissertation sought to explore these long-term sequelae and the possible interrelations between them. In the first experiment, sleep-dependent memory consolidation of neutral stimuli was probed in a chronic mTBI sample and a control, uninjured sample. I hypothesized memory consolidation would be reduced in the mTBI sample. However, sleep-dependent consolidation was found to be intact in the mTBI sample, despite differences in sleep architecture between groups. Given that risk for mood disorders is elevated following mTBI, in the second experiment, sleep-dependent memory consolidation of emotional images was assessed in groups that were similar to those assessed in Study 1, with the hypothesis that mTBI participants would have reduced consolidation. The mTBI group had reduced sleep-dependent memory consolidation (i.e., memory considation that occurred over a sleep period) but enhanced wake-dependent consolidation (i.e., memory consolidation that occurred over a wake period) of emotional (but not neutral) images. The mTBI group also unexpectedly exhibited a lack of emotion habituation (i.e., emotion desensitization). The third experiment attempted to replicate the latter (unexpected) finding (i.e., reductions in habituation in the mTBI group) while also probing physiological measures of emotion (e.g., heart rate deceleration), which provide an objective measure of emotion. I theorized that reduced habituation might increase the risk for mood disturbances in this population. I was not able to replicate findings of the second experiment, and, on the contrary, found mTBI participants had enhanced emotion habituation In the three experiments, we failed to find expected cognitive and emotional processing deficits in the mTBI samples. In future work, recruiting alternative subsamples of mTBI individuals (e.g., those with Post-concussive syndrome or those with 3 or more mTBIs) could provide insight into which individuals experience negative outcomes in the chronic stages of mTBI

Variability and potential sources of predictability of North American runoff

Understanding the space-time variability of runoff has important implications for climate because of the linkage of runoff and evapotranspiration and is a practical concern as well for the prediction of drought and floods. In contrast to many studies investigating the space-time variability of precipitation and temperature, there has been relatively little work evaluating climate teleconnections of runoff, in part because of the absence of data sets that lend themselves to commonly used techniques in climate analysis like principal components analysis. We examine the space-time variability of runoff over North America using a 50-year retrospective spatially distributed data set of runoff and other land surface water cycle variables predicted using a calibrated macroscale hydrology model, thus avoiding some shortcomings of past studies based more directly on streamflow observations. We determine contributions to runoff variability of climatic teleconnections, soil moisture, and snow for lead times up to a year. High and low values of these sources of predictability are evaluated separately. We identify patterns of runoff variability that are not revealed by direct analysis of observations, especially in areas of sparse stream gauge coverage. The presence of nonlinear relationships between large-scale climate changes and runoff pattern variability, as positive and negative values of the large-scale climate indices rarely show opposite teleconnections with a runoff pattern. Dry soil moisture anomalies have a stronger influence on runoff variability than wet soil. Snow, and more so soil moisture, in many locations enhance the predictability due to climatic teleconnections

Automated Upscaling of River Networks for Macroscale Hydrological Modeling

We developed a hierarchical dominant river tracing (DRT) algorithm for automated extraction and spatial upscaling of basin flow directions and river networks using fine-scale hydrography inputs (e. g., flow direction, river networks, and flow accumulation). In contrast with previous upscaling methods, the DRT algorithm utilizes information on global and local drainage patterns from baseline fine-scale hydrography to determine upscaled flow directions and other critical variables including upscaled basin area, basin shape, and river lengths. The DRT algorithm preserves the original baseline hierarchical drainage structure by tracing each entire flow path from headwater to river mouth at fine scale while prioritizing successively higher order basins and rivers for tracing. We applied the algorithm to produce a series of global hydrography data sets from 1/16 degrees to 2 degrees spatial scales in two geographic projections (WGS84 and Lambert azimuthal equal area). The DRT results were evaluated against other alternative upscaling methods and hydrography data sets for continental U. S. and global domains. These results show favorable DRT upscaling performance in preserving baseline fine-scale river network information including: (1) improved, automated extraction of flow directions and river networks at any spatial scale without the need for manual correction; (2) consistency of river network, basin shape, basin area, river length, and basin internal drainage structure between upscaled and baseline fine-scale hydrography; and (3) performance largely independent of spatial scale, geographic region, and projection. The results of this study include an initial set of DRT upscaled global hydrography maps derived from HYDRO1K baseline fine-scale hydrography inputs; these digital data are available online for public access at ftp://ftp.ntsg.umt.edu/pub/data/DRT/

Using a conceptual change approach as a teaching strategy for improving learners' understanding of Chemical Change in Physical Sciences.

Magister Educationis - MEd (Mathematics and Science Education)The purpose of this study is to investigate the use of a Conceptual Change Approach as a teaching strategy to improve learners' understanding of Chemical Change in Physical Sciences. In addition, learners' attitudes toward chemistry as a school subject and toward Conceptual Change texts were investigated. Moreover, learners' science process skills were also investigated. The study was underpinned by Conceptual Change Theory and Constructivism. The sample included 34 Grade 11 learners doing Physical Sciences. The case study is a secondary school in the Eastern Cape. For the purposes of this study both quantitative and qualitative research methods were used. Learners were given a pre- test and a post-test and an intervention in the form of a Conceptual Change text lesson. Thereafter, focus group interviews were used to examine learners' understanding in greater detail. Findings revealed that learners have several misconceptions that hinder learning related to chemical change. It is therefore imperative to find ways for remediation of these misconceptions. The results also showed that instruction based on the Conceptual Change Approach in which Conceptual Change Texts were used, caused significantly better attainment of concepts on chemical change, better remediation of misconceptions and enhanced understanding of chemical change. This study provides insight into the use of Conceptual Change as a teaching strategy to improve learners' understanding of challenging areas in Physical Sciences

Relationships Between Pacific and Atlantic Ocean Sea Surface Temperatures and U.S. Streamflow Variability

An evaluation of Pacific and Atlantic Ocean sea surface temperatures (SSTs) and continental U.S. streamflow was performed to identify coupled regions of SST and continental U.S. streamflow variability. Both SSTs and streamflow displayed temporal variability when applying the singular value decomposition (SVD) statistical method. Initially, an extended temporal evaluation was performed using the entire period of record (i.e., all years from 1951 to 2002). This was followed by an interdecadal-temporal evaluation for the Pacific (Atlantic) Ocean based on the phase of the Pacific Decadal Oscillation (PDO) (Atlantic Multidecadal Oscillation (AMO)). Finally, an extended temporal evaluation was performed using detrended SST and streamflow data. A lead time approach was assessed in which the previous year\u27s spring-summer season Pacific Ocean (Atlantic Ocean) SSTs were evaluated with the current water year continental U.S. streamflow. During the cold phase of the PDO, Pacific Ocean SSTs influenced streamflow regions (southeast, northwest, southwest, and northeast United States) most often associated with El Niño–Southern Oscillation (ENSO), while during the warm phase of the PDO, Pacific Ocean SSTs influenced non-ENSO streamflow regions (Upper Colorado River basin and middle Atlantic United States). ENSO and the PDO were identified by the Pacific Ocean SST SVD first temporal expansion series as climatic influences for the PDO cold phase, PDO warm phase, and the all years analysis. Additionally, the phase of the AMO resulted in continental U.S. streamflow variability when evaluating Atlantic Ocean SSTs. During the cold phase of the AMO, Atlantic Ocean SSTs influenced middle Atlantic and central U.S. streamflow, while during the warm phase of the AMO, Atlantic Ocean SSTs influenced upper Mississippi River basin, peninsular Florida, and northwest U.S. streamflow. The AMO signal was identified in the Atlantic Ocean SST SVD first temporal expansion series. Applying SVD, first temporal expansions series were developed for Pacific and Atlantic Ocean SSTs and continental U.S. streamflow. The first temporal expansion series of SSTs and streamflow were strongly correlated, which could result in improved streamflow predictability

Provenance of Cultural Colour Meanings - The Green Hat and other narratives from Sino-Finnish business encounters

In different cultures, colours are sometimes assigned different meanings. Understanding the origins of these cultural colour meanings has become increasingly important with the ongoing advances towards digitalization of business and communication, and the most recent phase of globalization. However, academic research has largely neglected this phenomenon. The purpose of this dissertation is to increase our understanding of the dynamics of cross-cultural meaning-making for colours by examining the provenance of cultural colour meanings. This is achieved by employing empirical studies set in Chinese-Finnish business contexts, taking into account particular perspectives induced by globalization and online media, and their implications on the developments within the intersections of the research domains of business communication, culture, and colour. Methodologically, this research applies an emic-etic cross-cultural approach, using within-method triangulation of qualitative methods to explore the phenomenon. The empirical materials consist of narrative, visual, and observation materials generated within studies conducted in China and in Finland between January 2007 and July 2009. The two countries were chosen due to the shift of interest of many Finland-based MNCs from China-as-a-factory to include China-as-a-market, and ensuing perception of previously unexplored cultural differences in visual conventions, colour meanings in particular. Engaging in the debate within management and communication studies this research suggests a potential synthesis between the systemic and the process views to Culture. It finds that the significance of some cultural forces is inherited and thus more persistent (systemic view), while that of other cultural forces is more dynamic and transforming in nature (process view). Consequently, by framing Culture as dynamic heritage, this research proposes a conceptualization for Provenance of cultural colour meanings, contributing to the Multimodal theory of colour. Likewise, this research propositions the significance of the expressive function of the mode of colour borrowing from the former art historical and psychoanalytic approaches as well as based on the present empirical studies. Consequently, engaging with the Interactionist theory of communication, this research suggests that Meaning-making for colour can be conceived as an expression of cultural experience whereby the communicators become expressors of their respective cultural background and experience. Finally, this dissertation advances our understanding of meaning-making for colour in a multimodal context by adding the cross-cultural dimension to previous models, and shows that different modes can elaborate, extend, enhance, and contradict each other

Origins of the midlatitude Pacific decadal variability

Analysis of multiple climate simulations shows much of the midlatitude Pacific decadal variability to be composed of two simultaneously occurring elements: One is a stochastically driven, passive ocean response to the atmosphere while the other is oscillatory and represents a coupled mode of the ocean‐atmosphere system. ENSO processes are not required to explain the origins of the decadal variability. The stochastic variability is driven by random variations in wind stress and heat flux associated with internal atmospheric variability but amplified by a factor of 2 by interactions with the ocean. We also found a coupled mode of the ocean‐atmosphere system, characterized by a significant power spectral peak near 1 cycle/20 years in the region of the midlatitude North Pacific and Kuroshio Extension. Ocean dynamics appear to play a critical role in this coupled air/sea mode

Low-frequency eddy modulations in the Hawaiian Lee Countercurrent : observations and connection to the Pacific Decadal Oscillation

Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 116 (2011): C12009, doi:10.1029/2011JC007286.Interannual-to-decadal time scale eddy variability in the Hawaiian Lee Countercurrent (HLCC) band is investigated using the available sea surface height, sea surface temperature, and surface wind stress data sets. In the HLCC band of 17°N–21.7°N and 170E°–160°W, the prevailing interannual eddy kinetic energy (EKE) signals show enhanced eddy activities in 1993–1998 and 2002–2006, and subpar eddy activities in 1999–2001 and 2007–2009. These interannual EKE signals exhibit little connection to the zonal HLCC velocity changes generated by the dipolar wind stress curl forcing in the immediate lee of the island of Hawaii. Instead, they are highly correlated to the time series of the Pacific Decadal Oscillation (PDO) index. Through a budget analysis for the meridional temperature gradient along the HLCC, we find that during the positive phase of the PDO index, the surface heat flux forcing induces cold (warm) sea surface temperature (SST) anomalies to the north (south) of the HLCC, intensifying the vertical shear between the surface, eastward-flowing HLCC and the subsurface, westward-flowing North Equatorial Current (NEC). This increased vertical shear enhances the baroclinic instability of the HLCC-NEC system and leads to a higher regional EKE level. The opposite processes occur when the PDO switches to a negative phase with the resulting lowered EKE level along the HLCC band. Compared to the surface heat flux forcing, the Ekman flux convergence forcing is found to play a minor role in modifying the meridional SST changes along the HLCC band.We acknowledge support from NOAA through grant NA17RJ1230 for S.Y. and P.H. and NASA’s Ocean Surface topography Mission through JPL contract 1207881 for B.Q.2012-06-0

Impacts of climate variability and future climate change on harmful algal blooms and human health

This is the final version of the article. Available from BioMed Central via the DOI in this record.Anthropogenically-derived increases in atmospheric greenhouse gas concentrations have been implicated in recent climate change, and are projected to substantially impact the climate on a global scale in the future. For marine and freshwater systems, increasing concentrations of greenhouse gases are expected to increase surface temperatures, lower pH, and cause changes to vertical mixing, upwelling, precipitation, and evaporation patterns. The potential consequences of these changes for harmful algal blooms (HABs) have received relatively little attention and are not well understood. Given the apparent increase in HABs around the world and the potential for greater problems as a result of climate change and ocean acidification, substantial research is needed to evaluate the direct and indirect associations between HABs, climate change, ocean acidification, and human health. This research will require a multidisciplinary approach utilizing expertise in climatology, oceanography, biology, epidemiology, and other disciplines. We review the interactions between selected patterns of large-scale climate variability and climate change, oceanic conditions, and harmful algae.This work was funded in part through grants from the NSF/NIEHS Centers for Oceans and Human Health, grant numbers NSF OCE04-32479 and NIEHS P50 ES012740 (EAL), NSF OCE-0432368 and NIEHS P50 ES012736 (LEF), NIEHS P50 ES012762 and NSF OCE-0434087 (SKM, MSP). SKM, VLT and NJM also were supported in part by the West Coast Center for Oceans and Human Health (WCCOHH) as part of the NOAA Oceans and Human Health Initiative, and this is WCCOHH publication no. 26. The WCCOHH is part of the National Marine Fisheries Service's Northwest Fisheries Science Center, Seattle, Washington