bluuebunny/crossref_metadata_2025 huggingface dataset:
A Cluster Sleep-Wake Scheduling Algorithm Based on 3D Topology Control in Underwater Sensor Networks
Authors: Zhang Wenbo , Wang Jing , Han Guangjie , Zhang Xinyue , Feng Yongxin
Published: January 2019

3D topology control in underwater sensor networks is of great significance to ensuring reliable and efficient operation of the network. In this paper, by analyzing the characteristics of an underwater sensor network, we take the cube as the basic unit to perform 3D partition of the monitoring area, define the 3D partition unit and basic cluster structure of the underwater sensor network, and arrange rotating temporary control nodes in the cluster. Then, a cluster sleep-wake scheduling algorithm is proposed that compares the remaining node energy. It selects the node with the largest remaining energy as the working node, and the remaining nodes complete the transition of dormancy and waiting states as long as they reach the preset dormancy time. The node state settings of this phase are completed by the temporary control node. Temporary control nodes selecting and sleep-wake scheduling are used in the algorithm through 3D topology control, which reduces energy consumption and guarantees maximum sensing coverage of the entire network and the connection rate of active nodes. Simulation results further verify the effectiveness of the proposed algorithm.
An OCARI-Based Wireless Sensor Network for Heat Measurements during Outdoor Fire Experiments
Authors: Carlotti Thierry , Silvani Xavier , Innocenti Eric , Morandini Frédéric , Bulté Nicolas , Dang Tuan
Published: January 2019

This study presents a new wireless measurement system for outdoor fire experiments based on an OCARI wireless sensor network (WSN). The open-source radio communication OCARI stack (‘Open Communication Protocol for Ad Hoc Reliable Industrial Instrumentation’) allows to overcome the limitations of the previous wireless solutions for fire measurements, especially those based on proprietary systems, such as Zigbee, wherein users cannot control energy consumption and timestamping. This paper presents the design of an Atmel/ARM-based platform compatible with the wireless OCARI stack, adapted to record and communicate data from heat transducers—namely, a K-type thermocouple and heat fluxmeter. A 5-node WSN using heat sensors faces a 10 m 2 natural fire of excelsior (pine wood) in outdoor conditions. Measurements from the OCARI-WSN were compared with the same measurements simultaneously recorded on a datalogger, a standard wired solution in fire science. Thus, six fire experiments were performed for different fuel loads, and the incident heat radiation varies with the fire size under variable wind conditions. The technological breakdown of timestamping identified in previous low-energy consumption and low-cost wireless systems is overcome by the present solution.
Visual Semantic Landmark-Based Robust Mapping and Localization for Autonomous Indoor Parking
Authors: Zhao Junqiao , Huang Yewei , He Xudong , Zhang Shaoming , Ye Chen , Feng Tiantian , Xiong Lu
Published: January 2019

Autonomous parking in an indoor parking lot without human intervention is one of the most demanded and challenging tasks of autonomous driving systems. The key to this task is precise real-time indoor localization. However, state-of-the-art low-level visual feature-based simultaneous localization and mapping systems (VSLAM) suffer in monotonous or texture-less scenes and under poor illumination or dynamic conditions. Additionally, low-level feature-based mapping results are hard for human beings to use directly. In this paper, we propose a semantic landmark-based robust VSLAM for real-time localization of autonomous vehicles in indoor parking lots. The parking slots are extracted as meaningful landmarks and enriched with confidence levels. We then propose a robust optimization framework to solve the aliasing problem of semantic landmarks by dynamically eliminating suboptimal constraints in the pose graph and correcting erroneous parking slots associations. As a result, a semantic map of the parking lot, which can be used by both autonomous driving systems and human beings, is established automatically and robustly. We evaluated the real-time localization performance using multiple autonomous vehicles, and an repeatability of 0.3 m track tracing was achieved at a 10 kph of autonomous driving.
A Survey on Massive MIMO Systems in Presence of Channel and Hardware Impairments
Authors: Mokhtari Zahra , Sabbaghian Maryam , Dinis Rui
Published: January 2019

Massive multiple input multiple output (MIMO) technology is one of the promising technologies for fifth generation (5G) cellular communications. In this technology, each cell has a base station (BS) with a large number of antennas, allowing the simultaneous use of the same resources (e.g., frequency and/or time slots) by multiple users of a cell. Therefore, massive MIMO systems can bring very high spectral and power efficiencies. However, this technology faces some important issues that need to be addressed. One of these issues is the performance degradation due to hardware impairments, since low-cost RF chains need to be employed. Another issue is the channel estimation and channel aging effects, especially in fast mobility environments. In this paper we will perform a comprehensive study on these two issues considering two of the most promising candidate waveforms for massive MIMO systems: Orthogonal frequency division multiplexing (OFDM) and single-carrier frequency domain processing (SC-FDP). The studies and the results show that hardware impairments and inaccurate channel knowledge can degrade the performance of massive MIMO systems extensively. However, using suitable low complex estimation and compensation techniques and also selecting a suitable waveform can reduce these effects.
Equilibrium between Road Traffic Congestion and Low-Carbon Economy: A Case Study from Beijing, China
Authors: Yang Shuxia , Ji Yu , Zhang Di , Fu Jing
Published: January 2019

China has allocated low-carbon targets into all regions and trades, and road traffic also has its own emission reduction targets. Congestion may increase carbon emissions from road traffic. It is worthwhile to study whether it is possible to achieve the goal of road traffic reduction by controlling congestion; that is, to achieve the equilibrium between traffic congestion and a low-carbon economy. The innovation of this paper is mainly reflected in the innovative topic selection, the introduction of a traffic index, and the establishment of the first traffic congestion and low-carbon economic equilibrium model. First, the relevant calculation method of the traffic index is introduced, and the traffic index is used to quantify the traffic congestion degree. Using the traffic index, GDP, and road passenger traffic volume, a nonlinear regression model of road traffic carbon emissions is constructed. Then, the calculation method of the carbon emission intensity of road traffic in the region is proposed. The equilibrium model of traffic congestion and a low-carbon economy is constructed to look for the degree of road traffic congestion that may occur under the permitted carbon emission intensity. Taking Beijing, where electric vehicles account for less than 3% of the total vehicles, as an example, it is difficult to achieve the equilibrium target between road traffic congestion and a low-carbon economy by alleviating traffic congestion in 2020. If the target of traffic carbon emission reduction in 2020 is adjusted from 40%–45% to 19.7% based on 2005, the equilibrium will be achieved. A negative correlation between road traffic carbon emissions and the reciprocal of the traffic index (1/TI) is found after eliminating the effects of GDP and PTV (road passenger traffic volume). As the traffic index decreases by units, the carbon emission reduction accelerates. The results show that carbon reduction targets cannot be simply allocated to various industries. The results of the research on the degree of the impact of traffic congestion on carbon emissions can be used as a basis for carbon reduction decisions of the traffic sector. The research method of this paper can provide a reference for the study of the equilibrium of traffic congestion and a low-carbon economy in other regions.
The Roles and Measurements of Proximity in Sustained Technology Development: A Literature Review
Authors: Omobhude Christian , Chen Shih-Hsin
Published: January 2019

In existing studies, sustainable technology development involves harnessing knowledge assets to improve technological development and innovation to create competitive advantage for a firm. In recent decades, there has been a huge amount of scholarly articles on how technology development and innovation sustain competitive advantage. However, until recently most research focused on the spatial component of innovation and its influence on sustained technology development. Many studies have used proximity to examine spatial and relational mechanisms that lead to knowledge spillover and sustainable technology development. Reviewing 123 scholarly articles relating to proximity of innovation (1980–2018), this paper attempts to explore both spatial and non-spatial factors that influence sustainable technology and innovation development including geographic, cognitive, organizational, social, and institutional proximity. The review showed that each proximity dimension has relative importance and can be peculiar. For example, geographical proximity highlights the role of location and relative distance range in determining knowledge spillovers, especially relevant for face-to-face interaction and conditions that require certain types of complex tacit knowledge. This paper makes important contributions to our understanding of spatial and non-spatial proximity factors associated with sustainable technology development. The review showed that interpersonal factors are important for knowledge transfer to take place as knowledge does not depend entirely on location. The findings show that commonly used approaches to measure proximities include patent data and nomenclature of territorial units for statistics, not widely accessible across contexts, which impacts research and development (R&D) policy development. Cognitive, social, and institutional dimensions are important for knowledge transfer, supported by interplay of other proximities that determine and influence sustained technology development. In addition, management of proximity influences how knowledge assets are used for innovation and sustained technology development.
Advancing Medical Tourism in the United Arab Emirates: Toward a Sustainable Health Care System
Authors: Al-Talabani Hallow , Kilic Hasan , Ozturen Ali , Qasim Suhad Othman
Published: January 2019

Medical tourism provides an essential advantage for destinations. On the other hand, the knowledge of developing competitive medical tourism destinations is still limited. This study models a conceptual framework on novel ways of sustaining the United Arab Emirate (UAE) Vision 2020 with reference to the existing models on behavior. In the current study, the Theory of Planned Behavior (TPB), which is health-related, along with the Finance, System and connection (FSC) model, is employed. Using an empirically based methodology, the data for the investigation is collected with the aid of a questionnaire. As such, the study employs finance, system, and connections variables which are commonly adopted in testing medical tourism development. The designed model incorporates these three important factors that have remained the focal points in the world of medical tourism. Hence, the result reveals empirical evidence suggesting that the finance, system, and the connection factors significantly foster the growth of tourist arrivals in Dubai. Moreover, it predicates that the significant improvement in the economy of Dubai administrative government is likely to be connected with the development of its medical infrastructure. Additionally, by employing the use of SMART PLS (partial least square) software package, the structural analysis tests, like model fit, further affirms the robustness of the results. In addition, the study presents policy implication for the stakeholders in the health sector, tourism sector, and the government.
Explicating Perceived Sustainability-Related Climate: A Situational Motivator of Pro-Environmental Behavior
Authors: Leung Yan Wah , Rosenthal Sonny
Published: January 2019

Individuals take cues from their surroundings when deciding whether to perform pro-environmental behaviors. Previous studies have acknowledged the role of structural, policy, and communication efforts to encourage pro-environmental behavior. Such studies demonstrate the importance of evaluating the external contexts when examining behaviors. Yet, there is a lack of explication of what external context is entailed. Expanding the concept of perceived sustainability-related climate (PSRC) used in organizational communication literature, this study proposes two dimensions that shape PSRC in the workplace—structural cues and social cues. The study then generalizes PSRC such that it is applicable in contexts beyond the workplace and proposes a 10-item scale to measure PSRC. Using confirmatory factor analysis, this study tests the factor structure and concurrent validity of the concept. The study also tests convergent validity of PSRC with social norms, perceived behavioral control, and attitudes.
Migrant Workers and Physical Health: An Umbrella Review
Authors: Mucci Nicola , Traversini Veronica , Giorgi Gabriele , Garzaro Giacomo , Fiz-Perez Javier , Campagna Marcello , Rapisarda Venerando , Tommasi Eleonora , Montalti Manfredi , Arcangeli Giulio
Published: January 2019

Migrants are mainly employed in “3D jobs” which are dirty, dangerous, and difficult, are characterized by monotony and intense rhythms, and are found in sectors with higher risks such as construction, heavy industry, and agriculture. The aim of this study is to construct a systematic review in order to identify the main occupational risks and occupational diseases of this category. Research included articles published from 2013 to 2018 on major online databases (PubMed, Cochrane Library, and Scopus), which were obtained using a combination of keywords (migrant workers, expatriates, physical health, diseases, illnesses, travel, travelers, work, and occupational medicine). The online search included 1109 references. We excluded 977 studies because they were unrelated to physical health and another 64 due to duplication. There were 68 articles which were analyzed, including six reviews and 62 original articles. The main risks which emerged are developing infectious diseases, metabolic cardiovascular diseases and manifesting a lower quality of life, in particular due to difficulties in accessing local health services. It will be crucial to implement the role of occupational medicine in order to introduce multilevel interventions designed to prevent work-related injuries and illnesses, and to promote healthier working environments.
Use of Electroencephalography (EEG) for the Analysis of Emotional Perception and Fear to Nightscapes
Authors: Kim Mintai , Cheon SangHyun , Kang Youngeun
Published: January 2019

As the necessity for safety and aesthetic of nightscape have arisen, the importance of nightscapes (i.e., nighttime landscape) planning has garnered the attention of mainstream consciousness. Therefore, this study was to suggest the guideline for nightscape planning using electroencephalography (EEG) technology and survey for recognizing the characteristics of a nightscape. Furthermore, we verified the electroencephalography (EEG) method as a tool for landscape evaluation. Therefore, this study analyzed the change of relative alpha wave and relative beta wave and perceived fear of participants depending on twelve nightscape settings (four types of settings: Built nightscape images group with an adult; Built nightscape images groups without an adult; Nature-dominant nightscape images with an adult; and Nature-dominant nightscape images without an adult). Our findings indicate that the most fearful nightscape setting was recorded in Built nightscape images groups without an adult figure in perceived fear result depending on four types of nightscape settings. In Nature-dominant nightscape images, on the other hand, the nightscape setting with an adult figure was more fearful than the setting without an adult. The interaction effect between landscape type (built and nature-dominant) and adult presence towards perceived fear was verified and it showed that the image with adult affects landscape type. For electroencephalography (EEG) results, several brain activities in the relative alpha and beta wave showed significant differences depending on nightscape settings, which situates electroencephalography (EEG) as an invaluable tool for evaluating landscapes. Based on our physiological electroencephalography (EEG) experiment, we provide a new analytic view of the nightscape. The approach we utilized enables a deeper understanding of emotional perception and fear among human subjects by identifying the physical environment which impacts how they experience nightscapes.
Land Border Tourism Resources in China: Spatial Patterns and Tourism Management
Authors: Zhang Shengrui , Zhong Linsheng , Ju Hongrun , Wang Yingjie
Published: January 2019

Land border tourism in China serves as a pillar industry in local economic development and is an important sector for international cooperation. This paper aims to fill the gap in the spatial pattern of land border tourism resources in China using geographical information systems (GIS) and spatial statistical methods. The pattern was analyzed from the aspects of numerical features, spatial variance, and spatial association at different spatial scales. The results show that 3341 land border tourism resources in China reveal significant clusters and outliers at both the prefectural and county scales, offering useful information for the management of tourism resources. Physical factors, cultural diversity, regional policies, the relationships between neighboring countries, and public facilities are shown to be the main factors influencing the patterns. It is suggested that the government should adjust its management policies based on the characteristics of local resources, conduct combinatorial development of different types of resources, strengthen the cooperation domestically and internationally, improve public facilities, and protect the local environment and ethnic culture.
An Improved Integer Transform Combining with an Irregular Block Partition
Authors: Weng Shaowei , Chen Yi , Hong Wien , Pan Jeng-Shyang , Chang Chin-Chen , Liu Yijun
Published: January 2019

After conducting deep research on all existing reversible data hiding (RDH) methods based on Alattar’s integer transform, we discover that the frequently-used method in obtaining the difference value list of an image block may lead to high embedding distortion. To this end, we propose an improved Alattar’s transform-based-RDH-method. Firstly, the irregular block partition method which makes full use of high correlation between two neighboring pixels is proposed to increase the embedding performance. Specifically, each image block is composed of a center pixel and several pixels surrounding this center pixel. Thus, the difference value list is created by using the center pixel to predict each pixel surrounding it. Since the center pixel is highly related to each pixel surrounding it, a sharp difference value histogram is generated. Secondly, the mean value of an image block in Alattar’s integer transform has embedding invariance property, and therefore, it can be used for increasing the estimation performance of a block’s local complexity. Finally, two-layer embedding is combined into our scheme in order to optimize the embedding performance. Experimental results show that our method is effective.
Real-Time Error-Free Reversible Data Hiding in Encrypted Images Using (7, 4) Hamming Code and Most Significant Bit Prediction
Authors: Chen Kaimeng , Chang Chin-Chen
Published: January 2019

In this paper, a novel, real-time, error-free, reversible data hiding method for encrypted images has been proposed. Based on the (7, 4) Hamming code, we designed an efficient encoding scheme to embed secret data into the least significant bits (LSBs) of the encrypted image. For reversibility, we designed a most significant bit (MSB) prediction scheme that can recover a portion of the modified MSBs after the image is decrypted. These MSBs can be modified to accommodate the additional information that is used to recover the LSBs. After embedding the data, the original image can be recovered with no error and the secret data can be extracted from both the encrypted image and the decrypted image. The experimental results proved that compared with existing methods, the proposed method can achieve higher embedding rate, better quality of the marked image and less execution time of data embedding. Therefore, the proposed method is suitable for real-time applications in the cloud.
Understanding the Neighborhood Concentration of Affluent Black Households in the 1990s
Authors: Malega Ron
Published: January 2019

This study examines the intersection of race, class, and place by exploring the neighborhood concentration of affluent black households in the United States during the 1990s using Census 2000 data. It adds to the literature seeking a more nuanced understanding of the black community. The author assesses the theories of spatial assimilation and place stratification in understanding the processes associated with the neighborhood-level concentration of affluent black households. Regression analyses reveal that, in general, such concentrations are positively associated with black neighborhood socioeconomic status and negatively associated with white status. Furthermore, neighborhood quality and demographic factors are important for understanding the geography of affluent black households. Additionally, the metropolitan characteristics of residential segregation, racial composition, and regional location affect the neighborhood concentration of affluent black households. Findings suggest place stratification theory provides greater explanatory power than spatial assimilation theory for understanding the neighborhood concentration of affluent black households.
Response of Aquatic Plants and Water Quality to Large-Scale Nymphoides peltata Harvest in a Shallow Lake
Authors: Zhu Jinge , Peng Zhaoliang , Liu Xin , Deng Jiancai , Zhang Yihui , Hu Weiping
Published: January 2019

Aquatic plant harvest has been widely considered a plant management measure, as it can physically remove the targeted plants quickly and efficiently. Few empirical studies have examined the effects of harvesting on water quality or the aquatic plant community in a complete lake ecosystem. A large area (196 km2) of floating-leaved Nymphoides peltata was harvested in Lake Taihu in 2013. The effects of harvesting on the coverage and biomass of N. peltata and on the submerged plant community were evaluated. The quantities of nitrogen and phosphorus removed by harvesting were calculated. Harvesting caused an immediate reduction in N. peltata coverage, and its coverage in the following year ranged from 29.2% to 95.1%. Wave conditions and interspecific competition were the main factors that influenced the response of the submerged plant community to N. peltata harvesting. Harvesting may favor the dominance of Hydrilla verticillata, which expands quickly at an average growth rate of 53 ± 14 g m−2 day−1. Harvesting a large amount of N. peltata has a positive effect on total nitrogen (TN), ammonium nitrogen (NH3-N), and chemical oxygen demand (CODMn) control but can lead to different consequences (e.g., increase in total phosphorus (TP) and algal concentration).
All Aboard for "SAM": A New Anticipatory Conceptual Model for Passenger Preconsumption in Cruise Tourism
Authors: Sharples Liz
Published: January 2019

Anticipation in the cruise sector is nothing new, and passengers are most likely to have to wait for their trips after purchase. Anticipation theory has shown that levels of anticipation will initially be high after purchase then decrease, rising again before the event takes place.
Extant research has considered anticipation but has not focused on changes in emotions in this anticipatory time phase. This study is particularly useful to cruise tour operators because of the lengthy booking periods in this sector compared to other holiday types. This research note considers
anticipation theory and analyzes the impacts of anticipatory emotion with cruise passengers. It proposes a new Spiked Anticipation Model (SAM), which identifies how consumer anticipation can vary during the prejourney phase. SAM considers anticipatory emotions and time, and spikes are noted
as the cruise anticipatory journey progresses. The research has also shown that there are a variety of both positive and negative anticipatory emotions that can be expressed during this stage. This investigation will extend academic understanding of anticipatory theory and provide cruise company
managers with a clearer understanding of consumer emotions in this phase that will help them to identify which services and products their cruise passengers may require in this preconsumptive journey stage, thus potentially enhancing customer satisfaction and increasing revenues.
N-Arylphenothiazines as strong donors for photoredox catalysis – pushing the frontiers of nucleophilic addition of alcohols to alkenes
Authors: Speck Fabienne , Rombach David , Wagenknecht Hans-Achim
Published: January 2019

A new range ofN-phenylphenothiazine derivatives was synthesized as potential photoredox catalysts to broaden the substrate scope for the nucleophilic addition of methanol to styrenes through photoredox catalysis. TheseN-phenylphenothiazines differ by their electron-donating and electron-withdrawing substituents at the phenyl group, covering both, σ and π-type groups, in order to modulate their absorbance and electrochemical characteristics. Among the synthesized compounds, alkylaminylatedN-phenylphenothiazines were identified to be highly suitable for photoredox catalysis. The dialkylamino substituents of theseN-phenylphenothiazines shift the estimated excited state reduction potential up to −3.0 V (vs SCE). These highly reducing properties allow the addition of methanol to α-methylstyrene as less-activated substrate for this type of reaction. Without the help of an additive, the reaction conditions were optimized to achieve a quantitative yield for the Markovnivkov-type addition product after 20 h of irradiation.
Excitation and Depletion of the Asteroid Belt in the Early Instability Scenario
Authors: Clement Matthew S. , Raymond Sean N. , Kaib Nathan A.
Published: January 2019

Containing only a few percentages of the mass of the moon, the current asteroid belt is around three to four orders of magnitude smaller than its primordial mass inferred from disk models. Yet dynamical studies have shown that the asteroid belt could not have been depleted by more than about an order of magnitude over the past ∼4 Gyr. The remainder of the mass loss must have taken place during an earlier phase of the solar system’s evolution. An orbital instability in the outer solar system occurring during the process of terrestrial planet formation can reproduce the broad characteristics of the inner solar system. Here, we test the viability of this model within the constraints of the main belt’s low present-day mass and orbital structure. Although previous studies modeled asteroids as massless test particles because of limited computing power, our work uses graphics processing unit acceleration to model a fully self-gravitating asteroid belt. We find that depletion in the main belt is related to the giant planets’ exact evolution within the orbital instability. Simulations that produce the closest matches to the giant planets’ current orbits deplete the main belt by two to three orders of magnitude. These simulated asteroid belts are also good matches to the actual asteroid belt in terms of their radial mixing and broad orbital structure.
Laser Guide Star for Large Segmented-aperture Space Telescopes. I. Implications for Terrestrial Exoplanet Detection and Observatory Stability
Authors: Douglas E. S. , Males J. R. , Clark J. , Guyon O. , Lumbres J. , Marlow W. , Cahoy K. L.
Published: January 2019

Precision wavefront control on future segmented-aperture space telescopes presents significant challenges, particularly in the context of high-contrast exoplanet direct imaging. We present a new wavefront control architecture that translates the ground-based artificial guide star concept to space with a laser source on board a second spacecraft, formation flying within the telescope’s field of view. We describe the motivating problem of mirror segment motion and develop wavefront sensing requirements as a function of guide star magnitude and segment motion power spectrum. Several sample cases with different values for transmitter power, pointing jitter, and wavelength are presented to illustrate the advantages and challenges of having a non-stellar-magnitude noise limited wavefront sensor for space telescopes. These notional designs allow increased control authority, potentially relaxing spacecraft stability requirements by two orders of magnitude and increasing terrestrial exoplanet discovery space by allowing high-contrast observations of stars of arbitrary brightness.
A Model of Solar Equilibrium: The Hydrodynamic Limit
Authors: Gunderson L. M. , Bhattacharjee A.
Published: January 2019

Helioseismology has revealed the internal density and rotation profiles of the Sun. Yet, knowledge of its magnetic fields and meridional circulation is confined much closer to the surface, and latitudinal entropy gradients are below detectable limits. While numerical simulations can offer insight into the interior dynamics and help identify which ingredients are necessary to reproduce particular observations, some features of the Sun can be understood analytically from an equilibrium perspective. Examples of such features include: the 1D density profile arising from steady-state energy transport from the core to the surface, and the tilting of isorotation contours in the convection zone (CZ) due to baroclinic forcing. To help answer the question of which features can be explained by equilibrium, we propose analyzing stationary axisymmetric ideal magnetohydrodynamic flows in the solar regime. By prescribing an appropriate entropy at the surface, we recover a rotation profile that reasonably matches observations in the bulk of the CZ. Additionally, by including the effects of poloidal flow, we reproduce a feature that is reminiscent of the near surface shear layer. However, no tachocline-like feature is seen in hydrodynamic equilibrium, suggesting the importance of either dynamics or magnetic fields in its description.
Testing Feedback-regulated Star Formation in Gas-rich, Turbulent Disk Galaxies
Authors: Fisher D. B. , Bolatto A. D. , White H. , Glazebrook K. , Abraham R. G. , Obreschkow D.
Published: January 2019

In this paper we compare the molecular gas depletion times and midplane hydrostatic pressure in turbulent, star-forming disk galaxies to internal properties of these galaxies. For this analysis we use 17 galaxies from the DYNAMO sample of nearby (z ∼ 0.1) turbulent disks. We find a strong correlation, such that galaxies with lower molecular gas depletion time (t
dep) have higher gas velocity dispersion (σ). Within the scatter of our data, our observations are consistent with the prediction that

made in theories of feedback-regulated star formation. We also show a strong, single power-law correlation between midplane pressure (P) and star formation rate surface density (ΣSFR), which extends for 6 orders of magnitude in pressure. Disk galaxies with lower pressure are found to be roughly in agreement with theoretical predictions. However, in galaxies with high pressure we find P/ΣSFR values that are significantly larger than theoretical predictions. Our observations could be explained with any of the following: (1) the correlation of ΣSFR−P is significantly sublinear; (2) the momentum injected from star formation feedback (p
*/m
*) is not a single, universal value; or (3) alternate sources of pressure support are important in gas-rich disk galaxies. Finally, using published survey results, we find that our results are consistent with the cosmic evolution of t
dep(z) and σ(z). Our interpretation of these results is that the cosmic evolution of t
dep may be regulated not just by the supply of gas but also by the internal regulation of star formation via feedback.
The Unusual Initial Mass Function of the Arches Cluster
Authors: Hosek Matthew W. , Lu Jessica R. , Anderson Jay , Najarro Francisco , Ghez Andrea M. , Morris Mark R. , Clarkson William I. , Albers Saundra M.
Published: January 2019

As a young massive cluster in the central molecular zone, the Arches cluster is a valuable probe of the stellar initial mass function (IMF) in the extreme Galactic center environment. We use multi-epoch Hubble Space Telescope observations to obtain high-precision proper-motion and photometric measurements of the cluster, calculating cluster membership probabilities for stars down to ∼1.8 M
⊙ between cluster radii of 0.25 and 3.0 pc. We achieve a cluster sample with just ∼6% field contamination, a significant improvement over photometrically selected samples that are severely compromised by the differential extinction across the field. Combining this sample with K-band spectroscopy of five cluster members, we forward model the Arches cluster to simultaneously constrain its IMF and other properties (such as age and total mass) while accounting for observational uncertainties, completeness, mass segregation, and stellar multiplicity. We find that the Arches IMF is best described by a one-segment power law that is significantly top-heavy: α = 1.80 ± 0.05 (stat) ± 0.06 (sys), where dN/dm ∝ m
−α
, though we cannot discount a two-segment power-law model with a high-mass slope only slightly shallower than local star-forming regions

but with a break at

. In either case, the Arches IMF is significantly different than the standard IMF. Comparing the Arches to other young massive clusters in the Milky Way, we find tentative evidence for a systematically top-heavy IMF at the Galactic center.
An FFT-based Solution Method for the Poisson Equation on 3D Spherical Polar Grids
Authors: Müller Bernhard , Chan Conrad
Published: January 2019

The solution of the Poisson equation is a ubiquitous problem in computational astrophysics. Most notably, the treatment of self-gravitating flows involves the Poisson equation for the gravitational field. In hydrodynamics codes using spherical polar grids, one often resorts to a truncated spherical harmonics expansion for an approximate solution. Here we present a non-iterative method that is similar in spirit, but uses the full set of eigenfunctions of the discretized Laplacian to obtain an exact solution of the discretized Poisson equation. This allows the solver to handle density distributions for which the truncated multipole expansion fails, such as off-center point masses. In 3D, the operation count of the new method is competitive with a naive implementation of the truncated spherical harmonics expansion with N

ℓ
 ≈ 15 multipoles. We also discuss the parallel implementation of the algorithm. The serial code and a template for the parallel solver are made publicly available.
Explaining Deviations from the Scaling Relationship of the Large Frequency Separation
Authors: Ong 王加 J. M. Joel 冕 , Basu Sarbani
Published: January 2019

Asteroseismic large frequency separations possess great diagnostic value. However, their expressions as scaling relations are predicated on homology arguments that may not hold in general, resulting in mass- and temperature-dependent deviations. The first-order asymptotic expressions, which should in principle account for this structural evolution, also deviate more from fitted frequency-separation estimates than the simple scaling relations and exhibit qualitatively different behavior. We present a modified asymptotic estimator and show that these discrepancies can be accounted for by the evolution of the acoustic turning points of the asteroseismic mode cavity, which is typically neglected in first-order asymptotic analysis. This permits us to use a single expression to accurately estimate the large frequency separations of main-sequence, ascending red giant branch, and red clump stellar models, except at transition points between two asymptotic regimes during the subgiant phase of evolution, where the WKB approach fails. The existence of such transition points provides theoretical justification for separately calibrated scaling relations for stars in different evolutionary stages.
Resistive and Multi-fluid RMHD on Graphics Processing Units
Authors: Wright A. J. , Hawke I.
Published: January 2019

In this work we present a proof of concept of CUDA-capable, resistive, multi-fluid models of relativistic magnetohydrodynamics (RMHD). Resistive and multi-fluid codes for simulating models of RMHD suffer from stiff source terms, so it is common to implement a set of semi-implicit time integrators to maintain numerical stability. We show, for the first time, that finite volume IMEX schemes for resistive and two-fluid models of RMHD can be accelerated by execution on graphics processing units, significantly reducing the demand set by these kinds of problems. We report parallel speed-ups of over 21× using double-precision floating-point accuracy, and highlight the optimization strategies required for these schemes, and how they differ from ideal RMHD models. The impact of these results is discussed in the context of the next-generation simulations of neutron star mergers.
The Milky Way Imaging Scroll Painting (MWISP): Project Details and Initial Results from the Galactic Longitudes of 25.°8–49.°7
Authors: Su Yang , Yang Ji , Zhang Shaobo , Gong Yan , Wang Hongchi , Zhou Xin , Wang Min , Chen Zhiwei , Sun Yan , Chen Xuepeng , Xu Ye , Jiang Zhibo
Published: January 2019

The Milky Way Imaging Scroll Painting project is an unbiased Galactic plane CO survey for mapping regions of

to +250° and

5.°2 with the 13.7 m telescope of the Purple Mountain Observatory. The legacy survey aims to observe the

,

, and C18O (J = 1–0) lines simultaneously with full-sampling using the nine-beam Superconducting SpectroScopic Array Receiver system with an instantaneous bandwidth of 1 GHz. In this paper, the completed 250 deg2 data from l = +25.°8 to +49.°7 are presented with a grid spacing of 30″ and a typical rms noise level of ∼0.5 K for

 at the channel width of 0.16 km

and ∼0.3 K for

 and C18O at 0.17 km

. The high-quality data, with moderate resolution (∼50″), uniform sensitivity, and high spatial dynamic range, allow us to investigate the details of molecular clouds (MCs) traced by the three CO isotope lines. Three interesting examples are briefly investigated, including distant Galactic spiral arms traced by CO emission with V
LSR < 0 km s−1, the bubble-like dense gas structure near the H ii region W40, and the MCs distribution perpendicular to the Galactic plane.
Rotation Curve of the Milky Way from Classical Cepheids
Authors: Mróz Przemek , Udalski Andrzej , Skowron Dorota M. , Skowron Jan , Soszyński Igor , Pietrukowicz Paweł , Szymański Michał K. , Poleski Radosław , Kozłowski Szymon , Ulaczyk Krzysztof
Published: January 2019

Flat rotation curves of spiral galaxies are considered as an evidence for dark matter, but the rotation curve of the Milky Way is difficult to measure. Various objects were used to track the rotation curve in the outer parts of the Galaxy, but most studies rely on incomplete kinematical information and inaccurate distances. Here, we use a sample of 773 Classical Cepheids with precise distances based on mid-infrared period–luminosity relations coupled with proper motions and radial velocities from Gaia to construct the accurate rotation curve of the Milky Way up to the distance of ∼20 kpc from the Galactic center. We use a simple model of Galactic rotation to measure the rotation speed of the Sun Θ0 = 233.6 ± 2.8 km s−1, assuming a prior on the distance to the Galactic center R
0 = 8.122 ± 0.031 kpc from the GRAVITY Collaboration. The rotation curve at Galactocentric distances 4 ≲ R ≲ 20 kpc is nearly flat with a small gradient of −1.34 ± 0.21 km s−1 kpc−1. This is the most accurate Galactic rotation curve at distances R > 12 kpc constructed so far.
Victor ou le patchwork des techniques
Authors: Chavarria Analia
Published: January 2019

La problématique autistique, complexe comme elle l’est, ne peut pas être vue au travers d’une seule approche. Désamorcer la dualité entre psychanalyse et techniques éducatives/comportementalistes, me paraît primordial à l’heure de travailler avec des personnes autistes car ces techniques, si nous les utilisons en prenant en compte la singularité de chaque enfant, peuvent leur apporter beaucoup de bénéfices. Victor, pré-adolescent autiste âgé de 13 ans, en est un exemple. Par différentes médiations, Victor a pu déposer ses inquiétudes et ses questionnements dans le cadre d’une prise en charge psycho-éducative, donnant lieu à un processus de subjectivation dont Victor était le principal protagoniste. « Victor ou le patchwork des techniques » a été mon expérience en tant que clinicienne au cours de laquelle j’ai tenté, pour reprendre la métaphore de Freud, de ne pas prendre l’échafaudage pour le bâtiment lui-même.
Compliance With Standard Guidelines for the Prevention of Occupational Transmission of Bloodborne and Airborne Pathogens: A Survey of Postanesthesia Nursing Practice
Authors: Tait Alan R , Voepel-Lewis Terri , Tuttle Dale B , Malviya Shobha
Published: January 2019

ABSTRACT

Background: Postanesthesia care unit (PACU) nurses' compliance with the guidelines for prevention of exposure to HIV, hepatitis B and C viruses (HBV, HCV), and tuberculosis (TB) were evaluated.

Method: A questionnaire was administered to 34 adult and pediatric PACU nurses at a large, tertiary care medical center.

Results: Eighty-one percent (n = 26) of respondents reported they always complied with the guidelines when caring for a HIV-infected or HBV-infected patient, but only 31.3% (n = 10) complied when the patient was considered low risk (p < .05). The most commonly cited reasons for noncompliance were no anticipated blood contact (53.6%, n = 15 ) or being too busy (25%, n = 10). Nineteen percent (n = 6) of PACU nurses reported at least one clean needlestick, and 16.1% (n = 5) reported a contaminated needlestick within the previous 12 months. One nurse reported having acquired active TB from a patient contact.

Conclusion: Results suggest that, although the PACU nurses surveyed reported knowledge of the standard guidelines, this was not always reflected in their practice. Identification of barriers to compliance may be important in developing educational strategies to reduce the risk to nurses.
Exploring Nursing Roles Across North American Borders
Authors: Kuehn Alice F , Chircop Andrea , Downe-Wamboldt Barbara , Sheppard-LeMoine Debbie , Murnaghan Donna , Elliott Judy , Critchley Kim , MacNaughton Neil S , Méndez Lourdes , Wittstock Lucille , Ramírez Guadalupe , Arteaga Sabrina , Espinoza Silvia , Herbert Rosemary , Judge-Ellis Tess , Cárdenas Velia
Published: January 2019

ABSTRACT

Professional nurses are challenged by the increasing complexity of their own healthcare delivery systems and by the growing interconnectivity of healthcare systems worldwide. There are increasing calls for practice across boundaries; however, the role and scope of nursing practice within individual countries are often unclear, ill-defined, and misunderstood by nurses from other countries. In this collaborative educational project among six schools of nursing located in Canada, México, and the United States, nursing students and faculty are exploring the role of the nurse within each country's healthcare system while striving to develop their multicultural awareness. Participating faculty describe the process, challenges, and keys to success found in creating and living this international project. They share strategies for addressing challenges, which included meeting deadlines, time differences, differing academic schedules, writing joint documents in two languages, designing and presenting a shared course, and creating an exchange process between the six partner schools. They describe the evolution of their working relationships, the language challenges, and the joy of coming together as newfound colleagues and friends.
A Nursing Partnership: The Forces of Magnetism Guiding Evidence-Based Practice in the Republic of Armenia
Authors: Bentson Joanne , Latayan Monica B , Olander Linda , Rocco Joanne
Published: January 2019

ABSTRACT

A team of nurses at North Shore University Hospital in Manhasset, New York, has been participating in a global collaboration with nurses at Erebouni Medical Center in Yerevan, Armenia. During this collaboration, they have built on work initiated by representatives of the American International Health Alliance and the American Nurses Credentialing Center (ANCC) to develop application of evidence-based practice in the Armenian nurse's work environment. Their collective efforts have resulted in initiating nursing assessments and plans of care, position descriptions and performance appraisals, competency assessment tools, and performance improvement tools. Overall, the respect for nurses at Erebouni Medical Center has significantly improved. In October 2004, nurses at Erebouni Medical Center were recognized by the ANCC with the Journey to Nursing Excellence Award.
Hong Kong Nurses' Perceptions of and Participation in Continuing Nursing Education
Authors: Lee Angel C K , Tiwari Agnes F Y , Choi Elizabeth W H Hui , Yuen K H , Wong Alan
Published: January 2019

ABSTRACT

As medical technologies change, practicing nurses need to update their knowledge and skills to ensure quality health care for patients and to minimize possible health hazards in the workplace. This article describes a study that explored Hong Kong hospital nurses' perceptions of and participation in continuing nursing education. It found that Hong Kong nurses participate actively in continuing education out of a sense of professional responsibility and personal interest. However, consistent with findings from other studies, the major factors hindering nurses' participation are finances, family commitments, and time.
Models, Measurement, and Strategies in Developing Critical-Thinking Skills
Authors: Brunt Barbara A
Published: January 2019

ABSTRACT

Health care professionals must use critical-thinking skills to solve increasingly complex problems. Educators need to help nurses develop their critical-thinking skills to maintain and enhance their competence. This article reviews various models of critical thinking, as well as methods used to evaluate critical thinking. Specific educational strategies to develop nurses' critical-thinking skills are discussed. Additional research studies are needed to determine how the process of nursing practice can nurture and develop critical-thinking skills, and which strategies are most effective in developing and evaluating critical thinking.
Nursing Education and Service Collaboration: Making a Difference in the Clinical Learning Environment
Authors: Palmer Sheri P , Cox Amy Harmer , Callister Lynn Clark , Johnsen Vickie , Matsumura Geraldine
Published: January 2019

ABSTRACT

This article focuses on innovative collaborative steps that were identified in recent research conducted by these authors on the relationship between academia and service. These steps are currently being implemented in the hope of improving the important role that the clinical environment plays in student nurses' education. Few factors in nursing education are as important as the clinical environment in which students do their training. This article elaborates on these steps and offers practical suggestions for improving the relationship between academia and service.