bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationships between photosynthesis and formaldehyde as a probe of isoprene emission
Authors: Zheng Y. , Unger N. , Barkley M. P. , Yue X.
Published: August 2015

Abstract. Atmospheric oxidation of isoprene emission from land plants affects radiative forcing of global climate change. There is an urgent need to understand the factors that control isoprene emission variability on large spatiotemporal scales but such direct observations of isoprene emission do not exist. Two readily available global-scale long-term observation-based data sets hold information about surface isoprene activity: gross primary productivity (GPP) and tropospheric formaldehyde column variability (HCHOv). We analyze multi-year seasonal linear correlations between observed GPP and HCHOv. The observed GPP–HCHOv correlation patterns are used to evaluate a global Earth system model that embeds three alternative leaf-level isoprene emission algorithms. GPP and HCHOv are decoupled in the summertime in the southeast US (r=−0.03). In the Amazon, GPP and HCHOv are weakly correlated in March-April-May (MAM), correlated in June-July-August (JJA) and weakly anticorrelated in September-October-November (SON). Isoprene emission algorithms that include soil moisture dependence demonstrate greater skill in reproducing the observed interannual seasonal GPP–HCHOv correlations in the southeast US and the Amazon. In isoprene emission models that include soil moisture dependence, isoprene emission is correlated with photosynthesis and anticorrelated with HCHOv. In an isoprene emission model without soil moisture dependence, isoprene emission is anticorrelated with photosynthesis and correlated with HCHOv. Long-term monitoring of isoprene emission, soil moisture and meteorology is required in water-limited ecosystems to improve understanding of the factors controlling isoprene emission and its representation in global Earth system models.
On the use of satellite-derived CH4 : CO2 columns in a joint inversion of CH4 and CO2 fluxes
Authors: Pandey S. , Houweling S. , Krol M. , Aben I. , Röckmann T.
Published: August 2015

Abstract. We present a method for assimilating total column CH4 : CO2 ratio measurements from satellites for inverse modeling of CH4 and CO2 fluxes using the variational approach. Unlike conventional approaches, in which retrieved CH4 : CO2 are multiplied by model-derived total column CO2 and only the resulting CH4 is assimilated, our method assimilates the ratio of CH4 and CO2 directly and is therefore called the ratio method. It is a dual tracer inversion, in which surface fluxes of CH4 and CO2 are optimized simultaneously. The optimization of CO2 fluxes turns the hard constraint of prescribing model-derived CO2 fields into a weak constraint on CO2, which allows us to account for uncertainties in CO2. The method has been successfully tested in a synthetic inversion setup. We show that the ratio method is able to reproduce assumed true CH4 and CO2 fluxes starting from a prior, which is derived by perturbing the true fluxes randomly. We compare the performance of the ratio method with that of the traditional proxy approach and the use of only surface measurements for estimating CH4 fluxes. Our results confirm that the optimized CH4 fluxes are sensitive to the treatment of CO2, and that hard constraints on CO2 may significantly compromise results that are obtained for CH4. We find that the relative performance of ratio and proxy methods have a regional dependence. The ratio method performs better than the proxy method in regions where the CO2 fluxes are most uncertain. However, both ratio and proxy methods perform better than the surface-measurement-only inversion, confirming the potential of spaceborne measurements for accurately determining fluxes of CH4 and other greenhouse gases (GHGs).
Toward enhanced capability for detecting and predicting dust events in the Western United States: the Arizona Case Study
Authors: Huang M. , Tong D. , Lee P. , Pan L. , Tang Y. , Stajner I. , Pierce R. B. , McQueen J. , Wang J.
Published: August 2015

Abstract. Dust aerosols affect human life, ecosystems, atmospheric chemistry and climate in various aspects. Studies have revealed intensified dust activity in the western US during the past decades despite the weaker dust activity in non-US regions. It is important to extend the historical dust records, to better understand their temporal changes, and use such information to improve the daily dust forecasting skill as well as the projection of future dust activity under the changing climate. This study develops dust records in Arizona in 2005–2013 using multiple observation datasets, including in-situ measurements at the surface Air Quality System (AQS) and Interagency Monitoring of Protected Visual Environments (IMPROVE) sites, and level 2 deep blue aerosol product by the Moderate Resolution Imaging Spectroradiometer. The diurnal and inter-annual variability of identified dust events are shown related to observed weather patterns (e.g., wind and soil moisture) and vegetation conditions, suggesting a potential for use of satellite soil moisture and vegetation index products to interpret and predict dust activity. Back-trajectories computed using NOAA's Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) Model indicate that the Sonoran and Chihuahuan deserts are important dust source regions during identified dust events in Phoenix, Arizona. Finally, we evaluate the performance of the US National Air Quality Forecasting Capability (NAQFC) 12 km CMAQ model during a recent strong dust event in the western US accompanied by stratospheric ozone intrusion. It is shown that the current modeling system well captures the temporal variability and the magnitude of aerosol concentrations during this event, and the usefulness and limitations of different observations in model evaluation are discussed. Directions of integrating observations to further improve dust emission modeling in CMAQ are also suggested.
GOMOS bright limb ozone data set
Authors: Tukiainen S. , Kyrölä E. , Tamminen J. , Kujanpää J. , Blanot L.
Published: August 2015

Abstract. We have created a daytime ozone profile data set from the measurements of the Global Ozone Monitoring by Occultation of Stars (GOMOS) instrument on board the Envisat satellite. This so-called GOMOS bright limb (GBL) data set contains ∼ 358 000 stratospheric daytime ozone profiles measured by GOMOS in 2002–2012. The GBL data set complements the widely used GOMOS nighttime data based on stellar occultation measurements. The GBL data set is based on the GOMOS daytime occultations but instead of the transmitted star light we use limb-scattered solar light. The ozone profiles retrieved from these radiance spectra cover the 18–60 km altitude range and have approximately 2–3 km vertical resolution. We show that these profiles are generally in better than 10 % agreement with the NDACC (Network for the Detection of Atmospheric Composition Change) ozonesonde profiles and with the GOMOS nighttime, MLS (Microwave Limb Sounder), and OSIRIS (Optical Spectrograph and InfraRed Imager System) satellite measurements. However, there is a 10–13 % negative bias at 40 km altitude and a 10–50 % positive bias at 50 km for solar zenith angles > 75°. These biases are most likely caused by stray light which is difficult to characterize and to remove entirely from the measured spectra. Nevertheless, the GBL data set approximately doubles the amount of useful GOMOS ozone profiles and improves coverage of the summer pole.
High temporal resolution estimates of columnar aerosol microphysical parameters from spectrum of aerosol optical depth by linear estimation: application to long-term AERONET and star-photometry measurements
Authors: Pérez-Ramírez D. , Veselovskii I. , Whiteman D. N. , Suvorina A. , Korenskiy M. , Kolgotin A. , Holben B. , Dubovik O. , Siniuk A. , Alados-Arboledas L.
Published: August 2015

Abstract. This work deals with the applicability of the linear estimation technique (LE) to invert spectral measurements of aerosol optical depth (AOD) provided by AERONET CIMEL sun photometers. The inversion of particle properties using only direct-sun AODs allows the evaluation of parameters such as effective radius (reff) and columnar volume aerosol content (V) with significantly better temporal resolution than the operational AERONET algorithm which requires both direct sun and sky radiance measurements. Sensitivity studies performed demonstrate that the constraints on the range of the inversion are very important to minimize the uncertainties, and therefore estimates of reff can be obtained with uncertainties less than 30 % and of V with uncertainties below 40 %. The LE technique is applied to data acquired at five AERONET sites influenced by different aerosol types and the retrievals are compared with the results of the operational AERONET code. Good agreement between the two techniques is obtained when the fine mode predominates, while for coarse mode cases the LE results systematically underestimate both reff and V. The highest differences are found for cases where no mode predominates. To minimize these biases, correction functions are developed using the multi-year database of observations at selected sites, where the AERONET retrieval is used as the reference. The derived corrections are tested using data from 18 other AERONET stations offering a range of aerosol types. After correction, the LE retrievals provide better agreement with AERONET for all the sites considered. Finally, the LE approach developed here is applied to AERONET and star-photometry measurements in the city of Granada (Spain) to obtain day-to-night time evolution of columnar aerosol microphysical properties.
Retrieval of vertical profiles of atmospheric refraction angles by inversion of optical dilution measurements
Authors: Fussen D. , Tétard C. , Dekemper E. , Pieroux D. , Mateshvili N. , Vanhellemont F. , Franssens G. , Demoulin P.
Published: August 2015

Abstract. In this paper, we consider occultations of celestial bodies through the atmospheric limb from low Earth orbit satellites and we show how the usual change of tangent altitude associated with atmospheric refraction is inseparably connected to a variation of the observed apparent intensity, for extended and pointlike sources. We demonstrate, in the regime of weak refraction angles, that atmospheric optical dilution and image deformation are strictly concomitant. The approach leads to the integration of a simple differential equation related to the observed transmittance in the absence of other absorbing molecules along the optical path. The algorithm does not rely on the absolute knowledge of the radiometer pointing angle that is related to the accurate knowledge of the satellite attitude. We successfully applied the proposed method to the measurements performed by two past occultation experiments: GOMOS for stellar and ORA for solar occultations. The developed algorithm (named ARID) will be applied to the imaging of solar occultations in a forthcoming pico-satellite mission.
The Global Network of Isotopes in Rivers (GNIR): integration of water isotopes in watershed observation and riverine research
Authors: Halder J. , Terzer S. , Wassenaar L. I. , Araguás-Araguás L. J. , Aggarwal P. K.
Published: August 2015

Abstract. We introduce a new online global database of riverine water stable isotopes (Global Network of Isotopes in Rivers, GNIR) and evaluate its longer-term data holdings. Overall, 218 GNIR river stations were clustered into three different groups based on the seasonal variation in their isotopic composition, which was closely coupled to precipitation and snowmelt water runoff regimes. Sinusoidal fit functions revealed phases within each grouping and deviations from the sinusoidal functions revealed important river alterations or hydrological processes in these watersheds. The seasonal isotopic amplitude of δ18O in rivers averaged 2.5 ‰, and did not increase as a function of latitude, like it does for global precipitation. Low seasonal isotopic amplitudes in rivers suggest the prevalence of mixing and storage such as occurs via lakes, reservoirs, and groundwater. The application of a catchment-constrained regionalized cluster-based water isotope prediction model (CC-RCWIP) allowed for direct comparison between the expected isotopic compositions for the upstream catchment precipitation with the measured isotopic composition of river discharge at observation stations. The catchment-constrained model revealed a strong global isotopic correlation between average rainfall and river discharge (R2 = 0.88) and the study demonstrated that the seasonal isotopic composition and variation of river water can be predicted. Deviations in data from model-predicted values suggest there are important natural or anthropogenic catchment processes like evaporation, damming, and water storage in the upstream catchment.
PERFORMANCE EVALUATION OF DSM EXTRACTION FROM ZY-3 THREE-LINE ARRAYS IMAGERY
Authors: Xue Y. , Xie W. , Du Q. , Sang H.
Published: August 2015

Abstract. ZiYuan-3 (ZY-3), launched in January 09, 2012, is China's first civilian high-resolution stereo mapping satellite. ZY-3 is equipped with three-line scanners (nadir, backward and forward) for stereo mapping, the resolutions of the panchromatic (PAN) stereo mapping images are 2.1-m at nadir looking and 3.6-m at tilt angles of ±22° forward and backward looking, respectively. The stereo base-height ratio is 0.85-0.95. Compared with stereo mapping from two views images, three-line arrays images of ZY-3 can be used for DSM generation taking advantage of one more view than conventional photogrammetric methods. It would enrich the information for image matching and enhance the accuracy of DSM generated. The primary result of positioning accuracy of ZY-3 images has been reported, while before the massive mapping applications of utilizing ZY-3 images for DSM generation, the performance evaluation of DSM extraction from three-line arrays imagery of ZY-3 has significant meaning for the routine mapping applications. The goal of this research is to clarify the mapping performance of ZY-3 three-line arrays scanners on china’s first civilian high-resolution stereo mapping satellite of ZY-3 through the accuracy evaluation of DSM generation. The comparison of DSM product in different topographic areas generated with three views images with different two views combination images of ZY-3 would be presented. Besides the comparison within different topographic study area, the accuracy deviation of the DSM products with different grid size including 25-m, 10-m and 5-m is delineated in order to clarify the impact of grid size on accuracy evaluation.
Impacts on wave-driven harbour agitation due to climate change in Catalan ports
Authors: Sierra J. P. , Casas-Prat M. , Virgili M. , Mösso C. , Sánchez-Arcilla A.
Published: August 2015

Abstract. The objective of the present work is to analyse how changes in wave patterns due to the effect of climate change can affect harbour agitation (oscillations within the port due to wind waves). The study focuses on 13 harbours located on the Catalan coast (NW Mediterranean) using a methodology with general applicability. To obtain the patterns of agitation, a Boussinesq-type model is used, which is forced at the boundaries by present/future offshore wave conditions extracted from recently developed high-resolution wave projections in the NW Mediterranean. These wave projections were obtained with the SWAN model forced by present/future surface wind fields projected, respectively, by five different combinations of global and regional circulation models (GCMs and RCMs) for the A1B scenario. The results show a general slight reduction in the annual average agitation for most of the ports, except for the northernmost and southernmost areas of the region, where a slight increase is obtained. A seasonal analysis reveals that the tendency to decrease is accentuated in winter. However, the inter-model variability is large for both the winter and the annual analysis. Conversely, a general increase with a larger agreement among models is found during summer, which is the period with greater activity in most of the studied ports (marinas). A qualitative assessment of the factors of variability seems to indicate that the choice of GCM tends to affect the spatial pattern, whereas the choice of RCM induces a more homogeneous bias over the regional domain.
Search for the 531-day-period wobble signal in the polar motion based on EEMD
Authors: Ding H. , Shen W.
Published: August 2015

Abstract. In this study, we use a nonlinear and non-stationary time series analysis method, the ensemble empirical mode decomposition method (EEMD), to analyze the polar motion (PM) time series (EOP C04 series from 1962 to 2013) to find a 531-day-period wobble (531 dW) signal. The 531 dW signal has been found in the early PM series (1962–1977), but cannot be found in the recent PM series (1978–2013) using conventional analysis approaches. By virtue of the demodulation feature of EEMD, the 531 dW can be confirmed to be present in PM based on the differences of the amplitudes and phases between different intrinsic mode functions. Results from three sub-series divided from the EOP C04 series show that the period of the 531 dW is subject to variations, in the range of 530.9–524 days, and its amplitude is also time-dependent (about 2–11 mas). Synthetic tests are carried out to explain why the 531 dW can only be observed in recent 30-year PM time series after using EEMD. The 531 dW is also detected in the two longest available superconducting gravimeter (SG) records, which further confirms the presence of the 531 dW. The confirmation of the 531 dW existence could be significant in establishing a more reasonable Earth rotation model and may effectively contribute to the prediction of the PM and its mechanism interpretation.
Brief Communication: Breeding vectors in the phase space reconstructed from time series data
Authors: Lynch E. , Kaufman D. , Sharma A. S. , Kalnay E. , Ide K.
Published: August 2015

Abstract. Bred vectors characterize the nonlinear instability of dynamical systems and so far have been computed only for systems with known evolution equations. In this article, bred vectors are computed from a single time series data using time-delay embedding, with a new technique, nearest-neighbor breeding. Since the dynamical properties of the standard and nearest-neighbor breeding are shown to be similar, this provides a new and novel way to model and predict sudden transitions in systems represented by time series data alone.
Cyclic fracturing during spine extrusion at Unzen volcano, Japan
Authors: Lamb O. D. , De Angelis S. , Umakoshi K. , Hornby A. J. , Kendrick J. E. , Lavallée Y.
Published: August 2015

Abstract. Rhythmic seismicity associated with spine extrusion is a well-documented phenomenon at a number of dome-forming volcanic systems. At Unzen volcano, Japan, a four year dome-forming eruption concluded with the emplacement of a spine from October 1994 to February 1995, offering a valuable opportunity to further investigate seismogenic processes at dome-forming volcanoes. Using continuous data recorded at a seismic station located close to the dome, this study explores trends in the seismic activity during the extrusion of the spine. We identify a total of 12 208 seismic events in the period between October 1994 and February 1995. Hourly event counts indicate cyclic activity with periods of ~ 40 to ~ 100 h, attributed to pulsatory ascent defined by strain localisation and faulting at the conduit margins. Waveform correlation revealed two strong clusters (a.k.a. multiplets, families) attributed to fracturing along the margins of the shallow, ascending plug. Further analysis indicates variable seismic velocities during spine extrusion, as well as migration of the cluster sources along the spine margins. Our interpretation of the results from seismic data analyses is supported by field and experimental observations, suggesting that the spine was extruded along an inclined conduit with brittle and ductile failure occurring along the margins. We infer that changes in stress conditions acting on the upper and lower spine margins led to deepening and shallowing of the faulting source, respectively. We demonstrate that the combination of geophysical, field and experimental evidence can help improve physical models of shallow conduit processes.
Nostalgia and La Jetée
Authors: Huebner Karla
Published: August 2015

This essay contemplates Chris Marker’s film La Jetée (1962) via Svetlana Boym’s conceptualization of “restorative” versus “reflective” nostalgia. It looks in part at the film’s presentation of the protagonist’s restorative nostalgia, but unlike previous examinations of nostalgia’s role in La Jetée, this essay foregrounds the viewer’s own experience of a reflective nostalgia for the film. The author considers her personal and subjective, and historically specific, encounters with La Jetée in relation to how the film may produce a similar nostalgia in others through its storytelling and unusual combination of photographic and cinematic form. Drawing also on Réda Bensmaïa’s semiotic and psychoanalytic analysis of the film’s “pictogrammatic” quality, the essay further considers the possible roles of trauma and masochism in the film and for its viewers, and relates the experience of watching La Jetée to that of watching An Occurrence at Owl Creek Bridge (also 1962). The essay therefore situates both films in the context of historically situated yet ever-changing lived experience.
Taboo Icons: The Bodily Photography of Andres Serrano
Authors: Shine Tyler
Published: August 2015

Andres Serrano’s photography is often dismissed as being shocking for the sake of being shocking. His infamous photograph Piss Christ (1987) is the oft-cited example at the center of the National Endowment for the Arts controversies during the Culture Wars of the 1980s and 1990s. I return to Piss Christ as a way to expand the interpretative scope of Serrano’s early photographs, which I call “taboo icons” because of their ambiguity and ability to crisscross symbolic boundaries in the unstable space between sacred and profane, thus making his images both powerful and potentially dangerous. Building upon previous scholarship that draws connections between modern and early modern aesthetic practices, I look to the material practices of Christianity in medieval Europe characterized by a sophisticated visual culture that mixed both the physical and the spiritual. The intensifying rejection and reverence of matter resulted in divergent responses, yet the contradictory nature of matter remained central to the ideological beliefs of Christianity where the doctrines of Creation, Incarnation, and Resurrection are at its core. Serrano’s visceral photographs are emphatically material and can productively be read vis-à-vis medieval visual culture. In doing so, this reading changes the narrow perception of Serrano’s early photographs and provides an alternative understanding of his artistic project that reinserts religion into contemporary American art discourse.
Compelled by the Diagram: Thinking through C. H. Waddington’s Epigenetic Landscape
Authors: Allen Matthew
Published: August 2015

Between 1940 and about 1960, Conrad Hal Waddington produced several illustrations to explain a concept central to his theories of developmental biology. The concept Waddington explained, the epigenetic landscape, was not based on settled science, and its implications were not easy to grasp. Unlike proponents of the most successful contemporary biological theory, Waddington was committed to including all biological phenomena–no matter how complex or unusual–in a single theoretical system. His intellectual style and use of images matched his ambition. Waddington used compelling images to get his readers to engage with and work through his theories. His images used a shifting, even contradictory, set of metaphors and analogical models, from train yards to crafted topological surfaces. Through an analysis of Waddington’s images and theories, I show that taking a close look at what scientific images show and how they show it is important for the historiography of science. Images can be effective at drawing viewers in, confounding them, and prodding them to ask questions; this is one reason images are necessary for science.
Curatorial Practice as Production of Visual & Spatial Knowledge: Panel Discussion, October 4, 2014
Authors: Scalissi Nicole , Langmead Alison , Smith Terry , Byers Dan , Morton Cynthia
Published: August 2015

The following is a transcription of a conversation between curators of art, science, and digital data about how their practice creates knowledge in their respective fields. Drawn from Pittsburgh’s rich institutional resources, the panelists include Dan Byers, (then) Richard Armstrong Curator of Contemporary Art, Carnegie Museum of Art; Dr. Alison Langmead, Director, Visual Media Workshop, Department of History of Art and Architecture, and Assistant Professor, School of Information Scienes, University of Pittsburgh; Dr. Cynthia Morton, Associate Curator of Botany, Carnegie Museum of Natural History; and Dr. Terry Smith, Andrew W. Mellon Professor of Contemporary Art History and Theory, University of Pittsburgh. Moderated by Nicole Scalissi, PhD candidate, Department of History of Art and Architecture, University of Pittsburgh. The panel took place as a part of Debating Visual Knowledge, a symposium organized by graduate students in Information Science and History of Art and Architecture at the University of Pittsburgh, October 3-5, 2014. The transcription has been edited for clarity.Curatorial Practice as Production of Visual & Spatial Knowledge
Foreword 前言
Authors: Minglu Gao
Published: August 2015

An introduction to the Open Ground Blog interviews included in this issue of Contemporaneity.
Decoding Double Desire: A Conversation with Ian McLean
Authors: Tyquiengco Marina
Published: August 2015

Ian McLean, editor of Double Desire: Transculturation and Indigenous Contemporary Art, discusses his book with Marina Tyquiengco.
The Question of Re-turning: Toward or Away from the Virtual?
Authors: Dejanovic Sanja
Published: August 2015

It is by now generally understood that the nature of events are central to Deleuze’s philosophical endeavour. This has not meant, however, that the process mapped out by this concept has been adequately grasped. Indeed, the lines mapping out events are obscured, theoretical, even otherworldly, whenever the complexities of the creating of the virtual and the actual as the created, are reductively conceived as giving way to two separated domains; two separated domains whereby the repeater would be forever condemned to be the result of an otherworldly will that “works through it,” one that would signal that they would never be capable of becoming worthy of the events that make a life.[i] The perspectival reality of the virtual with respect to the actual, which despite its fragmentary nature is in its entirety encompassed in each singular event, requires of us that we grasp what it is that Antonin Artaud’s points to when saying, I “am my son, my father, my mother, and myself.” It is not as though events perceived in the form of a virtual complex render beings inconsequential; instead, events are capable of ousting the verb “to be” in a double sense, because they enfold what is most affirmative in the activity of beings, the being of becoming whereby a life is born, always yet again, and as a function of which, as Alfred North Whitehead notes, what an actual being is, is how that entity becomes. It is adequate to its becoming. The actual as present-being expresses the verb “to be” in an ephemeral sense, or it is expressed by it in a restrictive way, while when affirmed as indistinct from the virtual, being, the verb “to be,” implies nothing else than the return of becoming. It is an untimely instant in which what is affirmed is the continuation of becoming; an instant that makes each event be the infinite becoming-finite of an actual being. So as to explore the nature of events in Deleuze’s philosophy, it is this displacement, the ousting of the verb “to be,” that I focus in on in this paper.
Requests in Saudi Pidgin Arabic
Authors: Al-Ageel Hessah
Published: August 2015

This study aims to investigate Saudi Pidgin Arabic (SPA) as one of the linguistic varieties that has emerged as a result of the interaction between Saudis and Asian workers. Linguistic and sociolinguistic analysis has been conducted for requestive expressions made by two generations of Saudi female speakers to female Asian workers in the cafeteria of a governmental institute in Riyadh, Saudi Arabia. The study shows that the use of SPA is largely limited to the simplest forms of verb and noun phrases that are used in Najdi Arabic (the variety that is used in the middle region of Arabian Peninsula), the lexifier language of SPA. The impact of English on the younger generation is shown by the tendency of younger participants to employ English expressions. A sociolinguistic analysis also shows the impact of the social variables of power, status, social distance and the age of the requester.    
Task Complexity and the Complexity of Written Language Production: A Review of Literature
Authors: Masrom Umi Kalsom , Mat Daud Nor Shidrah , Nik Mohd Alwi Nik Aloesnita
Published: August 2015

Robinson’s Cognition Hypothesis (Robinson 2001a, 2003a, 2003b, 2005, 2007a, 2007b)  predicts that more cognitively complex tasks along resource-directing dimension will lead to greater complexity of language production while cognitively complex tasks along resource-dispersing dimension will result in less complex language production. Various studies have investigated the effects of manipulating variables on these dimensions (i.e. resource-directing and resource-dispersing) either in oral or written language production. This paper compares and contrasts the results of several studies that were conducted by manipulating these variables in written language production. It also suggests guidelines for future research studies in this area. It concludes that further studies are necessary to investigate how language teachers can integrate and manipulate task-based instruction in their classrooms.  
Unusual Sites for Hemodialysis Vascular Access Construction and Catheter Placement: A Review
Authors: Lew Susie Q. , Nguyen Bao-Ngoc , Ing Todd S.
Published: August 2015

As more end-stage renal disease patients require hemodialysis and live longer, many will fail to develop or maintain a functioning upper extremity vascular access. When a patient exhausts vascular access sites in the upper extremities, new fistulas and grafts can be constructed in the lower extremities, thorax, and abdomen as long as a pair of proximate artery and vein provide adequate blood inflow and outflow, respectively. When only a moderate size vein with adequate blood flow provides a conduit to either a patent superior or inferior vena cava, inserting a double-lumen venous hemodialysis catheter can provide temporary or permanent access. We review the literature and report the unusual sites for hemodialysis vascular access and catheter placement.
Multi-Objective Optimization of Pulsatile Ventricular Assist Device Hemocompatibility Based on Neural Networks and a Genetic Algorithm
Authors: Xu Zihao , Yang Ming , Wang Xianghui , Wang Zhong
Published: August 2015

Purpose

Given the benefit of pulsatile blood flow for perfusion of coronary arteries and end organs, pulsatile ventricular assist devices (VADs) are still widely used as paracorporeal mechanical circulatory support devices in clinical applications. However, poor hemocompatibility limits the service period of the VADs. Most previous improvements on VAD hemocompatibility were conducted by trial-and-error CFD analysis, which does not easily arrive at the best solution.

Methods

In this paper, a multi-objective optimization method integrating neural networks and NSGA-II (Non-dominated Sorted Genetic Algorithm-II) based on FSI simulation was developed and applied to a pulsatile VAD to optimize its hemocompatibility. First, the VAD blood chamber was parameterized with the principal geometrical parameters. Three hemocompatibility indices including hemolysis, platelet activation, and platelet deposition were chosen as goal functions. The neural networks were built to fit the nonlinear relationship between goal functions and geometrical parameters. Next, a multi-objective optimization algorithm (NSGA-II) was used to search out the Pareto optimal solutions in the built neural networks. Finally, the best compromise solution was selected from the Pareto optimal solutions by a fuzzy membership approach and validated by FSI simulation.

Results

The best compromise solution simultaneously possesses an acceptable hemolysis index, platelet activation index, and platelet deposition index, and the corresponding relative errors between the indices predicted by optimization algorithm and the one calculated by FSI simulations are all less than 5%.

Conclusions

The results suggest that the proposed multi-objective optimization method has the potential for application in optimizing pulsatile VAD hemocompatibility, and may also be applied to other blood-wetted devices.
LVAD Inflow Cannula Covered with a Titanium Mesh Induces Neointimal Tissue with Neovessels
Authors: Miyamoto Takuma , Nishinaka Tomohiro , Mizuno Toshihide , Tatsumi Eisuke , Yamazaki Kenji
Published: August 2015

Background

Thrombus formation at the interfaces of inflow cannulas and left ventricular apexes is considered to be one of the predominant sources of thromboembolic complication. Use of a fine titanium mesh-covered inflow cannula is expected to prevent such thrombus formation by inducing neointimal tissue around the cannula.

Methods

Titanium pins (20 mm long, 3 mm diameter) covered with a fine titanium mesh (wire dia. 85 μm; volumetric porosity 40–70%) were developed to mimic the inflow cannulas of left ventricular assist devices (LVADs). Smooth-surface pins of the same size were also designed. The pins were implanted into the left ventricular apexes of rabbits. The rabbits were bled without anticoagulation for between 1 week and 1 year. The tissues around the pins were evaluated histologically.

Results

28 rabbits (mesh group, 15; smooth group, 13) were evaluated. The mesh-covered pins inhibited thrombus formation to a remarkable degree throughout the entire observation period. The tissues around the mesh-covered titanium pins appeared to be in the process of conversion from thrombus formation to granulation, resulting in the replacement of fibrotic tissue containing myofibroblasts with endothelialized and angiogenic tissue. On the surface of the mesh-covered pins, endothelial cells were arranged without platelet adhesion. The tissue formed around the smooth-surface pins was partially organized into a thrombus without angiogenesis.

Conclusions

The titanium-mesh surface modification prevented thrombus formation with formation of neointimal tissue with endothelialization and angiogenesis. This surface modification could prevent wedge thrombus formation among patients supported by LVADs.
A comparison of mammography, ultrasonography, and far-infrared thermography with pathological results in screening and early diagnosis of breast cancer
Authors: Yao Xiaoli , Wei Wen , Li Juanjuan , Wang Lijun , Xu ZhiLiang , Wan Yingwen , Li Kaiyang , Sun Shengrong
Published: August 2015

Background: Many breast-imaging techniques have been developed as primary clinical methods for identifying early-stage breast cancers and differentiating them from benign breast tumors. For the large population of China, any screening method that is rapid, economical, and accurate is worthy of evaluation.

Objective: To compare the effectiveness of mammography, color Doppler ultrasonography, and far-infrared thermography in the screening and early diagnosis of breast cancer.

Methods: Data from 2036 women with breast disease between January 2007 and May 2011 were included in this study. All patients underwent mammography, ultrasonography, and far-infrared thermography imaging. The diagnostic accuracy of the three methods was determined using postoperative pathological results as the diagnostic criterion standard.

Results: There were 480 patients found to have breast malignancies on pathological examination. The lesion diameter was <2 cm in 853 cases. Among them, breast cancer was found in 73 patients and carcinoma in situ in 22 patients. There was no difference in the accuracy of mammography and ultrasonography (96.1% versus 95.8%). However, there were significant differences between the accuracy of far-infrared thermography (97.1%) and ultrasonography and mammography. The sensitivity and specificity of far-infrared thermography was superior to that of mammography and ultrasonography in lesions <2 cm in diameter.

Conclusion: Far-infrared thermography is more accurate for breast cancer screening than ultrasonography and mammography for lesions <2 cm. It has comparable diagnostic accuracy to ultrasound and better diagnostic accuracy than mammography for lesions >2 cm in diameter.
Early decompressing craniectomy in patients with traumatic brain injury and cerebral edema
Authors: Gong Jiang-Biao , Wen Liang , Zhan Ren-Ya , Zhou Heng-Jun , Wang Fang , Li Gu , Yang Xiao-Feng
Published: August 2015

Background: Decompressing craniectomy (DC) is an important method for the management of severe traumatic brain injury (TBI).

Objective: To analyze the effect of prophylactic DC within 24 hours after head trauma TBI.

Methods: Seventy-two patients undergoing prophylactic DC for severe TBI were included in this retrospective study. Both of the early and late outcomes were studied and the prognostic factors were analyzed.

Results: In this series, cumulative death in the first 30 days after DC was 26%, and 28 (53%) of 53 survivors in the first month had a good outcomes. The factors including Glasgow Coma Score (GCS) score at admission, whether the patient had an abnormal pupil response and whether the midline shift was greater than 5 mm were most important prognostic factors for the prediction of death in the first 30 days and the final outcome at 6 months after DC.

Conclusion: Prophylactic DC plays an important role in the management of highly elevated ICP, especially when other methods of reduction of ICP are unavailable.
Unusual clinical manifestations of dengue infection in children in a tertiary care hospital in northeast Thailand
Authors: Duangmala Tanaporn , Lumbiganon Pagakrong , Kosalaraksa Pope
Published: August 2015

Background: Dengue virus infection has been a public health concern in Thailand. In the past decades, there has been recent interest concerning unusual clinical manifestations in both dengue fever (DF) and dengue hemorrhagic fever (DHF).

Objective: We described the unusual clinical manifestations and outcomes of children with dengue admitted to a tertiary care hospital in northeast Thailand.

Materials and Methods: A study was conducted on the 73 patients with serologically confirmed dengue infection admitted to Srinagarind Hospital, a tertiary care facility in northeast Thailand between January 2007 and August 2011.

Results: Of the 73 children examined, 42 (57%) were boys and 31 were girls. Their age ranged from 8 months to 14 years (median 11 years). Nine patients developed neurological symptoms, 6 patients had altered consciousness, and 3 patients convulsion. Among 9 patients with neurological symptoms, 1 patient had acute kidney injury, 1 had hepatic failure, and 1 had kidney and liver involvement, mostly associated with fluid resuscitation or prolonged shock. Apart from neurological symptoms, one patient developed infection associated hemophagocytic syndrome and was treated with intravenous immunoglobulin. Two patients died from multiple organ failure, and 1 patient was brought back home in a moribund condition. The other patients recovered completely.

Conclusion: Altered consciousness was the most commonly observed unusual neurological manifestation. Patients who did not develop acute kidney injury or liver failure had mild clinical courses and recovered from neurological symptoms without sequelae. Acute kidney injury was associated with fluid overload and/or prolonged shock. Careful fluid management and close monitoring for complications resulted in favorable outcomes.
Delayed presentation of congenital tibial pseudarthrosis and neurofibromatosis: a difficult union
Authors: Hatton Maxim J. , Ly Tho , Noor Saqib , Gollogly James G.
Published: August 2015

Background: A new case of congenital pseudarthrosis of the tibia (CPT) presents yearly to CSC, but treatment is prolonged, and not always successful.

Objective: To study the outcomes of treatment, and to determine whether a relationship with neurofibromatosis (NF) was of significance.

Methods: A review of the medical records at our centre revealed 11 cases of CPT, 5 of which were associated with neurofibromatosis.

Results: Most patients had multiple operations for their case of CPT, which did finally lead to union in 6 out of 6 cases with no NF, but in only 1 case out of 5 when NF was present.

Conclusion: Late presentation and severe deformity can be overcome, and union can be achieved, but NF has a deleterious effect on obtaining union.
Risk factors of delirium in elderly patients with hip fracture
Authors: Suwanpasu Sunee , Grinslade Susan , Wu Yow-Wu B. , Porock Davina
Published: August 2015

Background: Delirium is a leading cause of death and disability in the elderly with hip fracture. Identifying reliable risk factors for delirium is critical to support optimal outcomes for prevention and reducing delirium.

Objective: To quantify the reported factors associated to delirium for patients with hip fracture.

Methods: Electronic databases were searched (including Medline, Pub Med, CINAHL, EMBASE, Evidence Based Medicine Reviews, Cochrane Review, Web of Science, and PsycINFO) to identify all studies, published in English language that evaluated the risk factors of delirium hospitalized people with hip fracture. Two reviewers independently assessed methodology quality and extracted relevant data. The data from the included studies were summarized, and pooled estimates were calculated for 12 risk factors.

Results: Thirty-seven studies were included in the review and 25 in the meta-analysis. The incidence of delirium was 32.4% (95% confidence interval [CI] = 25.9%-39.5%). Six predisposing and four precipitating factors predicted delirium among older patients with hip fracture confirmed. The predisposing factors included advanced age (ES = 1.06, 95% CI = 1.03-1.09), male sex (ES = 1.34, 95% CI = 1.08-1.68), impairment of cognition (ES = 2.91, 95% CI = 1.91-4.42), and function (ES = 1.75, 95% CI = 1.39-2.2), comorbidity (ES = 1.59, 95% CI = 1.30-1.96), and health problems (ES = 2.64, 95% CI = 2.04-3.42). Precipitating factors were hypo- or hypernatremia (ES = 1.73, 95% CI = 1.14-2.64), depression (ES = 4.07, 95% CI = 1.95-8.49), more than three prescribed drugs (ES = 1.28, 95% CI = 1.10-1.49), and drugs including opioids (ES = 2.13, 95% CI = 1.42-3.18) and anticholinergic agents (ES = 2.10, 95% CI = 1.60-2.75).

Conclusion: This meta-analysis result provides evidence that these risk factors have a significant impact on delirium in elders with hip fracture during hospitalization. Developing formal screening, and effective preventive and management strategies for delirium is important.
Molecular mechanisms for NG-nitro-L-arginine methyl ester action against cerebral ischemia–reperfusion injury-induced blood–brain barrier dysfunction
Authors: Wang Hanghui , Song Yixin , Hao Dingjun , Du Lianfang
Published: August 2015

Background: Ischemic stroke, an acute neurological injury lacking an effective therapy, is a leading cause of death worldwide. The unmet need in stroke research is to identify viable therapeutic targets and to understand their interplay during cerebral ischemia-reperfusion (I/R) injury.

Objective: To explore the protective effects and molecular mechanism of NG-nitro-L-arginine methyl ester (L-NAME) in cerebral ischemia-reperfusion injury-induced blood-brain barrier (BBB) dysfunction.

Methods: Two hundred fifty-six rats were randomly assigned to a sham operation group, I/R group, and I/R with L-NAME treatment group. Brain water content was determined by calculating dry/wet weight. The permeability of the BBB was observed using an electron microscope and by determining the Evans Blue leakage from brain tissue on the ischemic side. The expression of brain MMP-9 and GFAP was determined using an immunohistochemical method. The expression of ZO-1 protein was determined by western blotting.

Results: We found that L-NAME remarkably attenuated the permeability of the BBB after I/R as assessed by Evans Blue leakage and brain water content (p < 0.05). This was further confirmed by examination of the ultrastructural morphology of the BBB using a transmission electron microscope. Furthermore, we found that expression of the zonae occludens-1 (ZO-1) was decreased in endothelial cells, and expression of MMP-9 and GFAP was increased in the basement membrane and astrocyte end-feet in vehicle control groups, respectively, but these changes could be prevented by L-NAME pretreatment.

Conclusion: These results suggested that the neuroprotective effects of L-NAME against BBB damage induced by I/R might be related to the upregulation of tight junction proteins and inhibition of MMP-9 and GFAP expression. L-NAME can be used as a potential MMP-9-based multiple targeting therapeutic strategy in cerebral I/R injury.
Acute effect of Russell’s viper (Daboia siamensis) venom on renal tubular handling of sodium in isolated rabbit kidney
Authors: Chaiyabutr Narongsak , Vasaruchapong Taksa , Chanhome Lawan , Rungsipipat Anudep , Sitprija Visith
Published: August 2015

Background: The common complication in cases of poisoning by Russell’s viper (Daboia siamensis) venom (RVV) is acute renal failure, but the pathogenesis involved in the alteration of kidney function is still not well understood.

Objective: To clarify the role of RVV in the pathogenesis of renal damage, the present study examines the functional short-term alterations acutely induced by RVV in isolated perfused rabbit kidney.

Methods: Effects of RVV on renal tubular handling of sodium including mean perfusion pressure (PP), the renalvascular resistance (RVR), the glomerular filtration rate (GFR), the urinary flow (V) and osmolar clearance (Cosm) were studied in two groups of isolated perfused rabbit kidneys; each group had four isolated rabbit kidneys. RVV was added to the perfusion system to obtain the final concentration of 10 ⃞g/ml.

Results: Immediate decreases in PP and RVR caused by the venom were significantly apparent (p < 0.05) in the first 15 min after RVV administration. A gradual rise in both PP and RVR occurred 15 min after the initial reduction of the first phase, but its remained below pretreatment values. The GFR, V, and Cosm decreased significantly throughout experiments after venom perfusion (p < 0.05). The total fractional sodium excretion increased significantly after venom perfusion throughout experiments, while significant reductions (p < 0.05) of renal tubular handling of sodium were apparent for proximal absolute reabsorption of sodium and proximal fractional reabsorption of sodium including marked reductions of distal absolute reabsorption of sodium and distal fractional reabsorption of sodium of the venom treated kidney. Optical microscopy of treated kidney tissue showed acute tubular necrosis at the end of experiment.

Conclusion: The present study suggests that an administration of RVV in the isolated rabbit kidney causes direct acute nephrotoxicity and acute alterations of main functional parameters that are probably mediated by either the direct action of venom components or an indirect effect from vasoactive mediators released from renal cells of the RVV-treated kidney.