bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonality and spatial variability of dynamic precipitation controls on the Tibetan Plateau
Authors: Curio Julia , Scherer Dieter
Published: February 2016

Abstract. The Tibetan Plateau (TP) is the origin of many large Asian rivers, which provide moisture for large regions in South and East Asia. Therefore, the water cycle on the TP and adjacent high mountain ranges and especially the precipitation distribution plays an important role for the water availability for billions of people in the regions downstream of the TP. Based on the High Asia Refined analysis (HAR) we analyse the influence of dynamic factors on precipitation, enhancing or suppressing precipitation development. We selected six precipitation controls, the horizontal and vertical wind speed at 300 hPa and in about two kilometres above ground, the atmospheric water transport, and the planetary boundary layer height. Focus of the study are the seasonality and the spatial variability of these precipitation controls and their dominant patterns. The results show that precipitation controls have different effects on precipitation in different regions and seasons. This depends mainly on the type of precipitation, convective or frontal/cyclonic precipitation. Additionally, the study reveals that the mid-latitude westerlies have a high impact on precipitation distribution on the TP and its surrounding year-round.
Perspectives on contextual vulnerability in discourses of climate conflict
Authors: Okpara U. T. , Stringer L. C. , Dougill A. J.
Published: February 2016

Abstract. The science of climate security and conflict is replete with controversies. Yet the increasing vulnerability of politically fragile countries to the security consequences of climate change is widely acknowledged. Although climate conflict reflects a continuum of conditional forces that coalesce around the notion of vulnerability, how different portrayals of vulnerability influence the discursive formation of climate conflict relations remains an exceptional but under-researched issue. This paper combines a systematic discourse analysis with a vulnerability interpretation diagnostic tool to explore (i) how discourses of climate conflict are constructed and represented, (ii) how vulnerability is communicated across discourse lines, and (iii) the strength of contextual vulnerability against a deterministic narrative of scarcity-induced conflict, such as that pertaining to land. Systematically characterising climate conflict discourses based on the central issues constructed, assumptions about mechanistic relationships, implicit normative judgements and vulnerability portrayals, provides a useful way of understanding where discourses differ. While discourses show a wide range of opinions "for" and "against" climate conflict relations, engagement with vulnerability has been less pronounced – except for the dominant context centrism discourse concerned about human security (particularly in Africa). In exploring this discourse, we observe an increasing sense of contextual vulnerability that is oriented towards a concern for complexity rather than predictability. The article concludes by illustrating that a turn towards contextual vulnerability thinking will help advance a constructivist theory-informed climate conflict scholarship that recognises historicity, specificity, and variability as crucial elements of contextual totalities of any area affected by climate conflict.
Nonstationarity of low flows and their timing in the eastern United States
Authors: Sadri S. , Kam J. , Sheffield J.
Published: February 2016

Abstract. The analysis of the spatial and temporal patterns of low flows as well as their generation mechanisms over large geographic regions can provide valuable insights and understanding for climate change impacts, regional frequency analysis, risk assessment of extreme events, and decision-making regarding allowable withdrawals. The goal of this paper is to examine nonstationarity in low flow generation across the eastern US and explore the potential anthropogenic influences or climate drivers. We use nonparametric tests to identify abrupt and gradual changes in time series of low flows and their timing for 508 USGS streamflow gauging sites in the eastern US with more than 50 years of daily data, to systematically distinguish the effects of human intervention from those of climate variability. A time series decomposition algorithm was applied to 1-day, 7-day, 30-day, and 90-day annual low flow time series that combines the Box–Ljung test for detection of autocorrelation, the Pettitt test for abrupt step changes and the Mann–Kendall test for monotonic trends. Examination of the USGS notes for each site showed that many of the sites with step changes and around half of the sites with an increasing trend have been documented as having some kind of regulation. Sites with decreasing or no trend are less likely to have documented influences on flows. Overall, a general pattern of increasing low flows in the northeast and decreasing low flows in the southeast is evident over a common time period (1951–2005), even when discarding sites with significant autocorrelation, documented regulation or other human impacts. The north–south pattern of trends is consistent with changes in antecedent precipitation. The main exception is along the mid-Atlantic coastal aquifer system from eastern Virginia northwards, where low flows have decreased despite increasing precipitation, and suggests that declining groundwater levels due to pumping may have contributed to decreased low flows. For most sites, the majority of low flows occur in one season in the late summer to fall, as driven by the lower precipitation and higher evaporative demand in this season, but this is complicated in many regions because of the presence of a secondary low flow season in the winter for sites in the extreme northeast and in the spring for sites in Florida. Trends in low flow timing are generally undetectable, although abrupt step changes appear to be associated with regulation.
Storms or cold fronts: what is really responsible for the extreme waves regime in the Colombian Caribbean coastal region?
Authors: Otero L. J. , Ortiz-Royero J. C. , Ruiz-Merchan J. K. , Higgins A. E. , Henriquez S. A.
Published: February 2016

Abstract. The aim of this study is to determine the contribution and importance of cold fronts and storms to extreme waves in different areas of the Colombian Caribbean in an attempt to determine the extent of the threat posed by the flood processes to which these coastal populations are exposed. Furthermore, the study wishes to establish the actions to which coastal engineering constructions should be subject. In the calculation of maritime constructions, the most important parameter is the height of the wave. For this reason, it is necessary to establish the design wave height to which a coastal engineering structure should be resistant. This wave height varies according to the return period considered. The significant height values for the areas focused on in the study were calculated in accordance with Gumbel's extreme value methodology. The methodology was evaluated using data from the reanalysis of the spectral National Oceanic and Atmospheric Administration (NOAA) WAVEWATCH III® (WW3) model for 15 points along the 1600 km of the Colombian Caribbean coastline (continental and insular) between the years 1979 and 2009. The results demonstrated that the extreme waves caused by tropical cyclones and those caused by cold fronts have different effects along the Colombian Caribbean coast. Storms and hurricanes are of greater importance in the Guajira Peninsula (Alta Guajira). In the central area (consisting of Baja Guajira, and the cities of Santa Marta, Barranquilla, and Cartagena), the strong impact of cold fronts on extreme waves is evident. However, in the southern region of the Colombian Caribbean coast (ranging from the Gulf of Morrosquillo to the Gulf of Urabá), the extreme values of wave heights are lower than in the previously mentioned regions, despite being dominated mainly by the passage of cold fronts. Extreme waves in the San Andrés and Providencia insular region present a different dynamic from that in the continental area due to their geographic location. The wave heights in the extreme regime are similar in magnitude to those found in Alta Guajira, but the extreme waves associated with the passage of cold fronts in this region have lower return periods than those associated with the hurricane season.
Geosphere Coupling and Hydrothermal Anomalies before the 2009 Mw 6.3 L'Aquila Earthquake in Italy
Authors: Wu L. X. , Zheng S. , De Santis A. , Qin K. , Di Mauro R. , Liu S. J. , Rainone M. L.
Published: February 2016

Abstract. The earthquake (EQ) anomalies associated with the April 6, 2009 Mw 6.3 L'Aquila EQ have been widely reported. Nevertheless, the reported anomalies have not been so far synergically analyzed to interpret or prove the potential LCA coupling process. Previous studies on b-value are also insufficient. In this work, the spatio-temporal evolution of several hydrothermal parameters related to the coversphere and atmosphere, including soil moisture, soil temperature, near-surface air temperature, and precipitable water, was comprehensively investigated. Air temperature and atmospheric aerosol were also statistically analyzed in time series with ground observations. An abnormal enhancement of aerosol occurred on March 30, 2009 and thus proved quasi-synchronous anomalies among the hydrothermal parameters from March 29 to 31 in particular places geo-related to tectonic thrusts and local topography. The three-dimensional (3D) visualization analysis of b-value revealed that regional stress accumulated to a high level, particularly in the L'Aquila basin and around regional large thrusts. Finally, the coupling effects of geospheres were discussed, and a conceptual LCA coupling mode was proposed to interpret the possible mechanisms of the multiple quasi-synchronous anomalies preceding the L’Aquila EQ. Results indicate that CO2-rich fluids in deep crust might have played a significant role in the local LCA coupling process.
Effect of polluted water on soil, sediments and plant contamination by heavy metals in El-Mahla El-Kobra, Egypt
Authors: Mahmoud E. , Ghoneim A. M.
Published: February 2016

Abstract. The discharge of untreated wastewater in drains Zefta and No. 5 is becoming a problem for many farmers in El-Mahla El-Kobra area, Egypt. The discharging water contains high levels of contaminants considered hazardous to the ecosystem. Some plants, soil, water, and sediment samples were collected from El-Mahla El-Kobra area to evaluate the contamination by heavy metals. The results showed that the heavy metals, pH, sodium adsorption ratio (SAR), BOD and COD in the water of drains Zefta and No. 5 exceeded permissible limits for irrigation. In rice and maize plants grown in soils irrigated by water from Zefta and No. 5 drains, the bioaccumulation factors for Cd, Pb, Zn, Cu and Mn were higher than 1.0. The heavy metals of irrigated soils from drains Zefta and No. 5 exceeded the upper limit of background heavy metals. In this study, the mean contaminant factor values of the drain No. 5 sediments revealed that Zn, Mn, Cu, Cd, Pb and Ni > 6, indicating very high contamination, which receive a huge amount of metallic pollution due to the direct discharge of wastewater from the urban and industrial area. The high bioaccumulation coefficients of Cynodon dactylon Phragmites australis and Typha domingensis growing in Zefta drain. These species can be considered as hyperaccumulators for, decontamination of polluted water. Thus, the wastewater in El-Mahla El-Kobra area must be treated before discharge in drains (Zefta and No. 5) and remediation of polluted soils from heavy metals.
Intravitreal Aflibercept for Choroidal Neovascularization in Ocular Sarcoidosis
Authors: Querques Lea , Querques Giuseppe , Miserocchi Elisabetta , Modorati Giulio , Bandello Francesco
Published: February 2016

Purpose

To report a case of choroidal neovascularization (CNV) in a patient with ocular sarcoidosis treated by intravitreal aflibercept.

Methods

A 27-year old man was referred to our department because of sudden visual acuity decrease (best-corrected visual acuity (BCVA) was 20/80 LE). Fundus examination showed bilateral optic disk swelling, retinal pigment epithelium changes at the posterior pole, yellowish chorioretinal lesions in the periphery, and the presence of a prominent peripapillary neovascular complex.

Results

The clinical diagnosis was most compatible with ocular sarcoidosis, later confirmed by mediastinal lymph node biopsy. Fluorescein and indocyanine green angiography confirmed the presence of active peripapillary type 2 (classic) CNV in both eyes. Given that the exudation of the peripapillary CNV harmed the fovea, the patient underwent a single intravitreal aflibercept injection LE. One month after the treatment, LE BCVA decreased to 20/125. Spectral-domain optical coherence tomography (SD-OCT) showed complete resolution of subretinal fluid but revealed outer retinal atrophy with complete loss of the ellipsoid zone (EZ) in the macula (possibly responsible for visual acuity worsening). Six months later, LE BCVA slightly increased to 20/100, and SD-OCT showed partial recovery of the EZ in the macula. No adverse events related to the treatment were recorded during follow-up.

Conclusions

We report a case of CNV in a patient with ocular sarcoidosis treated with intravitreal aflibercept. In our experience, intravitreal aflibercept injection achieved morphologic resolution for sarcoid-related peripapillary CNV.
Reconstruction of Periacetabular Tumours with Saddle Prosthesis or Custom-Made Prosthesis, Functional Results and Complications
Authors: Danışman Murat , Mermerkaya Musa Uğur , Bekmez Şenol , Ayvaz Mehmet , Atilla Bülent , Tokgözoğlu Ahmet M.
Published: February 2016

Reconstruction after resection of pelvic tumours is a major challenge. We report the outcomes and complications of 7 patients who underwent limb salvage following type II or type II, III pelvic resection and reconstruction using a saddle prosthesis or custom-made hemipelvic prosthesis. In our opinion, reconstruction using custom-made prostheses is better than placement of saddle prostheses because of a lower risk of complications and improved functional outcomes.
Cementless Total HIP Arthroplasty Using Biolox®Delta Ceramic-on-Ceramic Bearing in Patients with Osteonecrosis of the Femoral Head
Authors: Lim Seung-Jae , Kim Sang-Min , Kim Dong-Wook , Moon Young-Wan , Park Youn-Soo
Published: February 2016

Purpose

The purpose of this study was to evaluate the results of cementless total hip arthroplasty (THA) using a 32 mm or larger Biolox®delta ceramic-on-ceramic (CoC) bearing in patients with osteonecrosis of the femoral head after a minimum of 5 years of follow-up.

Materials and methods

We retrospectively analysed 44 patients (53 hips) who underwent cementless THA using Biolox®delta CoC bearing. There were 33 men (40 hips) and 11 women (13 hips) with the mean age of 49 years. A 36 mm head was used in 42 (79%) of 53 hips and a 32 mm head was used in 11 hips with smaller acetabular shells. The mean duration of follow-up was 5.3 years (range 5-6 years).

Results

The mean Harris Hip Score improved from 50 points preoperatively to 97 points at final follow-up (p<0.001). All acetabular and femoral components showed radiographic evidence of osseointegration. No osteolysis was observed. No patients sustained ceramic fracture. An audible hip noise was identified in 2 (4%) of the 53 hips (1 squeaking and 1 clicking). Survivorship with revision for any reason at a minimum of 5 years was 100% in the best-case scenario and 95 % in the worst-case scenario.

Conclusions

The minimum 5-year results of cementless THA using a 32 mm or larger Biolox®delta CoC bearing in patients with osteonecrosis of the femoral head were encouraging with excellent survivorship. However, it was also found that the risk of noise development remains even for the new alumina matrix composite ceramic.
Systemic Inflammatory Cytokine Analysis to Monitor Biomaterial Augmented Tissue Healing
Authors: Bryan Nicholas , Ashwin Helen , Smart Neil , Weyhe Dirk , Wohlert Stephen , Bayon Yves , Hunt John A.
Published: February 2016

Purpose

Hernias can be repaired by reinforcement of damaged fascia using biomaterials to provide stabilisation. Repair materials are usually porous, through which cells infiltrate, proliferate and secrete ECM. Their efficacy relies on good tissue integration and resolution of host defence mechanisms. Therefore, understanding the dynamics by which biomaterials interact with tissue will provide knowledge to advance prosthesis design. Furthermore, determining host response in real time would provide significant advantage both clinically and scientifically over the current terminal process of histology.

Methods

3 materials comprising synthetic and composite (synthetic materials hybridised with a resorbable biologic component) meshes were implanted into a rat full-thickness abdominal wall excision model. Their efficacy was evaluated using histopathology whilst also monitoring systemic concentrations of cytokines associated with inflammation and wound healing to predict material outcome over 12 weeks.

Results

The noncomposite material (polyester) and Material B (polypropylene mesh with oligocaprone film and polydioxanone glue) stimulated the largest degree of adhesion from the 3 materials tested, although after 28 days adhesions were stronger to Material B. Histologically, all 3 materials integrated well with abdominal musculature and infiltrated completely with cells.

Conclusions

Analysis of systemic inflammation biomarkers confirmed inflammation elicited by surgeries and meshes irrespective of their composition. However, at an early postoperative endpoint (i.e., 1 week), some biomarkers, namely, IL-18 and RANTES, appeared to discriminate the noncomposite mesh from the composite materials, although in this study all materials successfully repaired the defects without recurrence or external indicators of postoperative chronic pain.
Predictive Models for Arteriovenous Fistula Maturation
Authors: Al Shakarchi Julien , McGrogan Damian , Van der Veer Sabine , Sperrin Matthew , Inston Nicholas
Published: February 2016

Purpose

Haemodialysis (HD) is a lifeline therapy for patients with end-stage renal disease (ESRD). A critical factor in the survival of renal dialysis patients is the surgical creation of vascular access, and international guidelines recommend arteriovenous fistulas (AVF) as the gold standard of vascular access for haemodialysis. Despite this, AVFs have been associated with high failure rates. Although risk factors for AVF failure have been identified, their utility for predicting AVF failure through predictive models remains unclear. The objectives of this review are to systematically and critically assess the methodology and reporting of studies developing prognostic predictive models for AVF outcomes and assess them for suitability in clinical practice.

Methods

Electronic databases were searched for studies reporting prognostic predictive models for AVF outcomes. Dual review was conducted to identify studies that reported on the development or validation of a model constructed to predict AVF outcome following creation. Data were extracted on study characteristics, risk predictors, statistical methodology, model type, as well as validation process.

Results

We included four different studies reporting five different predictive models. Parameters identified that were common to all scoring system were age and cardiovascular disease.

Conclusions

This review has found a small number of predictive models in vascular access. The disparity between each study limits the development of a unified predictive model.
Comparison of Intensive versus Standard Hemodialysis Central Venous Catheter Dysfunction Protocol Using rt-PA: A Quality Assurance Initiative
Authors: Wilson Jo-Anne S. , Mossop Paula , Soroka Steven D. , Dipchand Christine , Drost Sarah , Sheehy Niall , Tennankore Karthik
Published: February 2016

Purpose

Catheter locking solutions such as recombinant tissue plasminogen activator (rt-PA) are used to treat and prevent clotting of hemodialysis (HD) catheters during HD treatments and the interdialytic period. However, evidence to guide the use of rt-PA for catheter dysfunction is limited.

Methods

We evaluated outcomes using two catheter dysfunction protocols in a cohort of consecutive prevalent dialysis patients (Jan 2013 to Sep 2014) undergoing HD with a tunneled catheter. In the intensive protocol, rt-PA was administered to all catheters based on blood flow and/or line reversal. In the standard protocol, rt-PA administration was based only on blood flow. The primary outcome was the rate of rt-PA use for catheter malfunction (rt-PA treatment days/1000 total line days; [TLD]). Secondary outcomes included the cost of rt-PA/TLD and the rate of catheter-related bacteremia.

Results

There were 26 and 35 patients managed by the intensive and standard protocols, respectively. The rate of rt-PA use was 52/1000 TLD (intensive) versus 39/1000 TLD (standard) (rate ratio 1.30, 95% CI 1.12-1.52 CI, p<0.001). The rate of bacteremia was 0.43 and 0.22/1000 TLD for the intensive and standard protocols, respectively (p = 0.491). The cost of rt-PA was CDN $5.58 and CDN $6.15 per TLD for the intensive protocol and standard protocol groups (p<0.001).

Conclusions

Managing catheter dysfunction based on line reversal and blood flow as opposed to only blood flow was associated with a higher rate of rt-PA use, but at a reduced overall cost.
Accessing Totally Implantable Venous Access Systems on the day of Placement does not Significantly Increase the Risk of Infection
Authors: Young Shamar J. , Young Linda J. , Vogel Jeffery , Sutkowski Raymond , Venkataperumal Satish
Published: February 2016

Purpose

Totally implantable venous access systems (ports) are commonly placed and have a low complication rate. The most common complication is infection, which can have very negative effects on patients resulting in hospitalization and/or treatment delay in the setting of neoplasm. While a number of variables have been studied in relation to diminishing infectious rates, one remaining question is the effect of accessing the port on day of placement, which is the aim of this retrospective study.

Materials and methods

After internal review board approval the electronic medical records of 2,006 patients who underwent port placement between 10/1/2008 and 9/30/2013 were reviewed. Of these patients 628 were excluded as they did not have complete placement and removal data available, leaving 1378 patients in our cohort.

Results

There was a significantly longer number of infection-free catheter days in the out-patient cohort as compared to the in-patient cohort (p = 0.027). In-patients mean day after placement when the port was first accessed (DAP) (0.5) was statistically earlier (closer to placement) than the out-patients DAP (7.2) (p<0.0001). However, the increased likelihood of infection could not be explained by DAP (p = 0.2029) even when controlling for in-patient and out-patient status (p = 0.97).

Conclusions

Accessing the port on the day of placement does not significantly contribute to an increased likelihood of infection. This study seems to indicate that placing a port on the first day of outpatient therapy likely optimally balances respect for patient time with infection control.
Creating Arteriovenous Fistulas in Patients with Chronic Central Venous Obstruction
Authors: Jennings William C. , Maliska Charles Miles , Blebea John , Taubman Kevin E.
Published: February 2016

Purpose

Central venous obstruction Occlusion (CVO) has been considered a contraindication for creating a vascular access due to fear of developing a swollen extremity. However, many of these individuals developed large collateral veins and are asymptomatic. We report our experience constructing arteriovenous fistulas (AVFs) in these challenging patients.

Methods

Patients with a new AVF constructed in the presence of known CVO were identified. Venous imaging confirmed proximal obstruction and extensive collateral venous return. The AVF was constructed in the extremity with the most favorable ultrasound vessel mapping and collateral central venous outflow. Arterial inflow via the radial artery was utilized when feasible.

Results

AVFs associated with known CVO were constructed in 19 patients during an eight-year time period. The mean age was 53 years, 63% were female, and 58% diabetic. Arterial inflow was from the radial artery in 15 patients and the brachial or axillary artery in 5 individuals. Post-operative AVF flow volumes were 415-910 mL/min (mean = 640 mL/min). Eight patients (42%) developed some degree of arm edema. Two resolved without intervention. The others required inflow banding (n = 2), outflow branch coiling (n = 1), and/or recanalization with angioplasty (n = 4) of the CVO to resolve swelling. Mean follow-up was 14 months. Two AVFs failed at 8 and 16 months. Primary and cumulative patency rates were 49% and 100% at 12 months and 39% and 80% at 24 months, respectively.

Conclusions

CVO need not preclude the creation of a successful AVF. Extensive venous collaterals and avoiding high-flow AVFs are important elements for success. Cumulative patency was 80% at 24 months.
El pensamiento de Pierre Bourdieu: Apuntes para una mirada arqueológica
Authors: Fowler William R. , Zavaleta Lemus Eugenia
Published: February 2016

Pierre Bourdieu es uno de los teóricos contemporáneos de la acción social más estudiados en diferentes campos de las ciencias sociales, porque sus postulados invitan a la superación de las antinomias o los dualismos clásicos de la sociología tradicional (objetivismo/subjetivismo, estructura/agencia, individuo/sociedad, materia/idea, micro/macro, cuali/cuanti) y porque se ha identificado con la superación de los determinismos y sustancialismos, construyendo enfoques más relacionales y procesuales.Sus principales influencias teóricas provienen del marxismo, del estructuralismo francés, de las filosofías de Martin Heidegger, Edmund Husserl, Maurice Merleau-Ponty, Raymond Aron y Ludwig Wittgenstein; inclusive de la tradición epistemológica francesa, que enfatiza el no-positivismo y antievolucionismo.
Universidad Tecnológica de El Salvador. Un caso de valoración patrimonial en el centro histórico de San Salvador
Authors: Campos Solórzano Melissa Regina
Published: February 2016

El Salvador, fue uno de los países cuyo auge surgió luego del proceso de Independencia con la llegada de la época republicana. Las ganancias que produjo el cultivo de café permitieron la construcción de edificaciones elitistas con marcadas influencias de la arquitectura importada de Europa en las inmediaciones de lo que hoy se constituye como el centro histórico de San Salvador.En este contexto territorial, pero resignificado culturalmente inició en 1986 la expansión arquitectónica del campus de la Universidad Tecnológica de El Salvador, la cual al día de hoy conforma un paisaje urbano particular con 21 edificaciones color ocre y crema dispersas en el extremo poniente del centro de la ciudad, así se refleja el compromiso agresivo de la Utec —más allá de su comunidad universitaria— que se extiende a la sociedad a través de la conservación del patrimonio cultural universitario.
Primeramente Dios, yo la alivio. El legado de Lorenzo Amaya en Nueva York
Authors: Molina Tamacas Carmen
Published: February 2016

En 2011, la Editorial Campana de Nueva York publicó una recopilación de testimonios de parteras salvadoreñas —Primeramente Dios, yo la alivio— realizada por el investigador Lorenzo Amaya Guevara (1942-2015).El libro fue realizado en coautoría con la lingüista española Paquita SuárezCoalla y es parte del trabajo realizado a finales de los años 80 y principios de los 90 en Ciudad Barrios, San Miguel, por el grupo Visión Cuscatleca. Las historias de vida incluyen leyendas, dietas, rituales, oraciones, cosmovisión y medicina natural.
Spectrofluorometric Determination of Putrescine Using Orthophthaldehyde as a Fluorophore: A Novel Method
Authors: Oyelakin Oladele , Traoré Moumouny , Mbaye El Hadji Babacar , Konté Abdourahmane , Cissé Lamine , Faye Abdoulaye N , Faye Ousman , Mbaye Moussa , Kital Khemesse , Seye Gaye , Coly Atanasse , Tine Alphonse , Delattre François
Published: February 2016

This paper concerns spectrofluorometric analysis of putrescine using orthophthaladehyde as a fluorophore in aqueous alkaline medium. Wavelengths of excitation and emission in acid, neutral, and alkaline media were different. There is a maximum intensity of fluorescence in alkaline medium 24 h after complexation compared with other media. Putrescine and orthophthaladehyde are used at an equimolar ratio, and the product is kinetically stable in alkaline medium. Calibration curves obtained gave limits of detection and quantification of 39 and 65 ng/mL, respectively. The correlation coefficient obtained in alkaline medium was 0.992 at pH 12. Results obtained largely showed a good reproducibility of our method.
A Novel Reconfiguration Strategy of a Delta-Type Parallel Manipulator
Authors: Balmaceda-Santamaría Albert Lester , Castillo-Castaneda Eduardo , Gallardo-Alvarado Jaime
Published: February 2016

This work introduces a novel reconfiguration strategy for a Delta-type parallel robot. The robot at hand, whose patent is pending, is equipped with an intermediate mechanism that allows for modifying the operational Cartesian workspace. Furthermore, singularities of the robot may be ameliorated owing to the inherent kinematic redundancy introduced by four actuable kinematic joints. The velocity and acceleration analyses of the parallel manipulator are carried out by resorting to reciprocal-screw theory. Finally, the manipulability of the new robot is investigated based on the computation of the condition number associated with the active Jacobian matrix, a well-known procedure. The results obtained show improved performance of the robot introduced when compared with results generated for another Delta-type robot.
Approximate Dynamic Programming in Tracking Control of a Robotic Manipulator
Authors: Szuster Marcin , Gierlak Piotr
Published: February 2016

This article focuses on the implementation of an approximate dynamic programming algorithm in the discrete tracking control system of the three-degrees of freedom Scorbot-ER 4pc robotic manipulator. The controlled system is included in an articulated robots group which uses rotary joints to access their work space. The main part of the control system is a dual heuristic dynamic programming algorithm that consists of two structures designed in the form of neural networks: an actor and a critic. The actor generates the suboptimal control law while the critic approximates the difference of the value function from Bellman's equation with respect to the state. The residual elements of the control system are the PD controller, the supervisory term and an additional control signal. The structure of the supervisory term derives from the stability analysis performed using the Lyapunov stability theorem. The control system works online, the neural networks' weights-adaptation procedure is performed in every iteration step, and the neural networks' preliminary learning process is not required. The performance of the control system was verified by a series of computer simulations and experiments performed using the Scorbot-ER 4pc robotic manipulator.
A General Contact Force Analysis of an Under-Actuated Finger in Robot Hand Grasping
Authors: Ha Xuan Vinh , Ha Cheolkeun , Nguyen Dang Khoa
Published: February 2016

This paper develops a mathematical analysis of contact forces for the under-actuated finger in a general under-actuated robotic hand during grasping. The concept of under-actuation in robotic grasping with fewer actuators than degrees of freedom (DOF), through the use of springs and mechanical limits, allows the hand to adjust itself to an irregularly shaped object without complex control strategies and sensors. Here the main concern is the contact forces, which are important elements in grasping tasks, based on the proposed mathematical analysis of their distributions of the n-DOF under-actuated finger. The simulation results, along with the 3-DOF finger from the ADAMS model, show the effectiveness of the mathematical analysis method, while comparing them with the measured results. The system can find magnitudes of the contact forces at the contact positions between the phalanges and the object.
Reliability Architecture for Collaborative Robot Control Systems in Complex Environments
Authors: Tang Liang , Jiang Yunliang , Lou Jungang
Published: February 2016

Many different kinds of robot systems have been successfully deployed in complex environments, while research into collaborative control systems between different robots, which can be seen as a hybrid internetware safety-critical system, has become essential. This paper discusses ways to construct robust and secure reliability architecture for collaborative robot control systems in complex environments. First, the indication system for evaluating the real-time reliability of hybrid internetware systems is established. Next, a dynamic collaborative reliability model for components of hybrid internetware systems is proposed. Then, a reliable, adaptive and evolutionary computation method for hybrid internetware systems is proposed, and a timing consistency verification solution for collaborative robot control internetware applications is studied. Finally, a multi-level security model supporting dynamic resource allocation is established.
A Mathematics Greenhouse
Authors: Rodriguez Anthony M.
Published: February 2016

Students create authentic models in community-based projects while learning about composting and mathematics.
Connecting Functions in Geometry and Algebra
Authors: Steketee Scott , Scher Daniel
Published: February 2016

Students see that geometric transformations—dilation and translation—correspond to algebraic parameters—m and b—in the familiar equation for a linear function.
Integer Solutions of Binomial Coefficients
Authors: Gilbertson Nicholas J.
Published: February 2016

Context and underlying structure explain why the formula for binomial coefficients always produces an integer solution
By way of introduction: Probability and Statistics
Authors: Damas Rebecca , Avila Christine
Published: February 2016

Were we to poll classroom teachers on which strand of mathematics is most neglected, there is a good chance that they would nominate probability and statistics.
Puppy Love
Authors: Cady Jo Ann , Wells Pamela J.
Published: February 2016

To elicit creative student thinking, this open-ended problem asks solvers to analyze area and perimeter.
February 2016 Problems
Authors: Roscoe Matt B. , Pelikan Stephan
Published: February 2016

A monthly set of problems is aimed at a variety of ability levels.
Making Sense of Data: Context Matters
Authors: Lovett Jennifer N. , Lee Hollylynne S.
Published: February 2016

Gain insight into the ways that students reason about measurement units and use data to draw conclusions.
A Vehicle for Bivariate Data Analysis
Authors: Roscoe Matt B.
Published: February 2016

Top-selling cars in America can be the catalyst that drives an analysis of data.
A Fair and Balanced Approach to the Mean
Authors: Peters Susan A. , Bennett Victoria Miller , Young Mandy , Watkins Jonathan D.
Published: February 2016

A sequence of five activities, progressing from concrete to abstract, can help students develop deep understandings of the mean.
Exponent Rummy
Authors: Griffith Leah
Published: February 2016

As classroom teachers, we try to provide opportunities for students to practice and use the algebra skills they are learning in ways that are nonroutine. We also want to help students connect the big ideas of math with the skills they are learning as part of the balance between understanding concepts and procedures. Math games can be used to accomplish these goals.
Evaluating Mathematics Curricular Resources
Authors: Polly Drew
Published: February 2016

Readers share news about happenings in the field of elementary school mathematics education, views on matters pertaining to teaching and learning mathematics in the early childhood or elementary school years, and reactions to previously published opinion pieces or articles.
Subitizing Games: Assessing Preschoolers' Number Understanding
Authors: MacDonald Beth L. , Shumway Jessica F.
Published: February 2016

Use young children's quick attention toward numerosity to evaluate their grasp of number while they engage in game play.
Using Representations of Fraction Multiplication
Authors: Webel Corey , Krupa Erin , McManus Jason
Published: February 2016

Contextual tasks such as the Milk problem and the Cupcake problem can illuminate operations with fractions, but not all visual models align with the standards.
Interactive Bulletin Boards
Authors: Van Hof Jill
Published: February 2016

Attractive bulletin boards enhance the classroom environment; moreover, those designed for learning tasks can also effectively promote problem solving and consolidate learning. Boards are easily adapted to levels of ability, grade, and complexity; they offer students real-world connections and engaging ways to interact with peers and with math concepts.
Probe method for measuring the diffusion coefficient in edge plasma
Authors: Amemiya Hiroshi , Uehara Kazuya , Ohshima Shinsuke , Mizuuchi Tohru
Published: February 2016

A probe method to measure the diffusion coefficient and the ion temperature in the edge plasma is proposed. The probe is constructed as an asymmetric double probe, where one electrode is sensitive to the direction of magnetic field while the other is insensitive to it. The ratio of ion saturation currents to two electrodes is used to determine the diffusion coefficient from which the ion temperature is estimated. The saturation currents are calculated by taking the anisotropic diffusion to the probe into account. The present probe method is applicable in the edge plasma even with such a complicated magnetic field as that in helical devices.
Improvement in performance of solution-processed indium–zinc–tin oxide thin-film transistors by UV/O3 treatment on zirconium oxide gate insulator
Authors: Naik Bukke Ravindra , Avis Christophe , Chowdhury Md Delwar Hossain , Kim Taehun , Lin Tengda , Jang Jin
Published: February 2016

We studied solution-processed amorphous indium–zinc–tin oxide (a-IZTO) thin-film transistors (TFTs) with spin-coated zirconium oxide (ZrO
x
) as the gate insulator. The ZrO
x
gate insulator was used without and with UV/O3 treatment. The TFTs with an untreated ZrO
x
gate dielectric showed a saturation mobility (μsat) of 0.91 ± 0.29 cm2 V−1 s−1, a threshold voltage (V
th) of 0.28 ± 0.36 V, a subthreshold swing (SS) of 199 ± 37.17 mV/dec, and a current ratio (I
ON/I
OFF) of ∼107. The TFTs with a UV/O3-treated ZrO
x
gate insulator exhibited μsat of 2.65 ± 0.43 cm2 V−1 s−1, V
th of 0.44 ± 0.35 V, SS of 133 ± 24.81 mV/dec, and I
ON/I
OFF of ∼108. Hysteresis was 0.32 V in the untreated TFTs and was eliminated by UV/O3 treatment. Also, the leakage current decreased significantly when the IZTO TFT was coated onto a UV/O3-treated ZrO
x
gate insulator.
Effects of plasmonic field due to gold nanoparticles and magnetic field on photocurrents of zinc porphyrin–viologen linked compound-gold nanoparticle composite films
Authors: Yonemura Hiroaki , Niimi Tomoki , Yamada Sunao
Published: February 2016

Composite films of zinc-porphyrin–viologen (ZnP–V2+) linked compound containing six methylene group [ZnP(6)V]–gold nanoparticles (AuNP) were fabricated by combining electrostatic layer-by-layer adsorption and the Langmuir–Blodgett method. The anodic photocurrents of the ZnP(6)V–AuNP composite films are higher than those of the ZnP(6)V films. The large photocurrents in ZnP(6)V–AuNP composite films are most likely attributable to the combination of localized surface plasmon resonance due to AuNP and photoinduced intramolecular electron transfer from excited state of ZnP to V2+. The photocurrents of the ZnP(6)V–AuNP composite films increase in the presence of magnetic field. The photocurrents increase with low magnetic fields (B ≤ 150 mT) and are almost constant under high magnetic fields (B ≥ 150 mT). Magnetic field effects (MFEs) were clearly observed for both ZnP(6)V–AuNP composite films and ZnP(6)V films. The MFEs can be explained by a radical pair mechanism.
Reduction in lateral lipid mobility of lipid bilayer membrane by atmospheric pressure plasma irradiation
Authors: Suda Yoshiyuki , Tero Ryugo , Yamashita Ryuma , Yusa Kota , Takikawa Hirofumi
Published: February 2016

Plasma medicine is an emerging research field in which various applications of electrical discharge, especially in the form of nonequilibrium plasma at atmospheric pressure, are examined, for example, the application of plasma to biological targets for various purposes such as selective killing of tumor cells and blood stanching. We have focused on the behavior of an artificial cell membrane system at the solid–liquid interface. To evaluate the lateral lipid mobility, we measured the diffusion coefficient of the supported lipid bilayer (SLB) composed of dioleoylphosphatidylcholine with fluorescence recovery after photobleaching by confocal laser scanning microscopy. It was found that the diffusion coefficient was decreased by plasma irradiation and that the diffusion coefficient decreasing rate proceeded with increasing plasma power. We investigated the effects of stimulation with an equilibrium chemical, H2O2, on the SLB and confirmed that the diffusion coefficient did not change at least up to a H2O2 concentration of 5 mM. These results indicate that transient active species generated by plasma play critical roles in the reduction in SLB fluidity. The effects of the two generated major oxidized lipid species, hydroxyl- or hydroperoxy-phosphatidylcholine (PC) and acyl-chain-truncated PCs terminated with aldehyde or carboxyl group, on lateral lipid mobility are discussed.
Dawn‐dusk asymmetries in rotating magnetospheres: Lessons from modeling Saturn
Authors: Jia Xianzhe , Kivelson Margaret G.
Published: February 2016

Spacecraft measurements reveal perplexing dawn‐dusk asymmetries of field and plasma properties in the magnetospheres of Saturn and Jupiter. Here we describe a previously unrecognized source of dawn‐dusk asymmetry in a rapidly rotating magnetosphere. We analyze two magnetohydrodynamic simulations, focusing on how flows along and across the field vary with local time in Saturn's dayside magnetosphere. As plasma rotates from dawn to noon on a dipolarizing flux tube, it flows away from the equator along the flux tube at roughly half of the sound speed (Cs), the maximum speed at which a bulk plasma can flow along a flux tube into a lower pressure region. As plasma rotates from noon to dusk on a stretching flux tube, the field‐aligned component of its centripetal acceleration decreases and it flows back toward the equator at speeds typically smaller than
. Correspondingly, the plasma sheet remains far thicker and the field less stretched in the afternoon than in the morning. Different radial force balance in the morning and afternoon sectors produce asymmetry in the plasma sheet thickness and a net dusk‐to‐dawn flow inside of L = 15 or equivalently, a large‐scale electric field (E) oriented from postnoon to premidnight, as reported from observations. Morning‐afternoon asymmetry analogous to that found at Saturn has been observed at Jupiter, and a noon‐midnight component of E cannot be ruled out.
Optimal observation network design for conceptual model discrimination and uncertainty reduction
Authors: Pham Hai V. , Tsai Frank T.‐C.
Published: February 2016

This study expands the Box‐Hill discrimination function to design an optimal observation network to discriminate conceptual models and, in turn, identify a most favored model. The Box‐Hill discrimination function measures the expected decrease in Shannon entropy (for model identification) before and after the optimal design for one additional observation. This study modifies the discrimination function to account for multiple future observations that are assumed spatiotemporally independent and Gaussian‐distributed. Bayesian model averaging (BMA) is used to incorporate existing observation data and quantify future observation uncertainty arising from conceptual and parametric uncertainties in the discrimination function. In addition, the BMA method is adopted to predict future observation data in a statistical sense. The design goal is to find optimal locations and least data via maximizing the Box‐Hill discrimination function value subject to a posterior model probability threshold. The optimal observation network design is illustrated using a groundwater study in Baton Rouge, Louisiana, to collect additional groundwater heads from USGS wells. The sources of uncertainty creating multiple groundwater models are geological architecture, boundary condition, and fault permeability architecture. Impacts of considering homoscedastic and heteroscedastic future observation data and the sources of uncertainties on potential observation areas are analyzed. Results show that heteroscedasticity should be considered in the design procedure to account for various sources of future observation uncertainty. After the optimal design is obtained and the corresponding data are collected for model updating, total variances of head predictions can be significantly reduced by identifying a model with a superior posterior model probability.
Symptoms of Knee Instability as Risk Factors for Recurrent Falls
Authors: Nevitt Michael C. , Tolstykh Irina , Shakoor Najia , Nguyen Uyen‐Sa D. T. , Segal Neil A. , Lewis Cora , Felson David T. ,   for the Multicenter Osteoarthritis Study Investigators
Published: February 2016

Objective

Whether knee instability contributes to the increased risk of falls and fractures observed in persons with knee osteoarthritis (OA) has not been studied. We examined the association of knee buckling with the risk of falling and fall‐related consequences in older adults with, or at high risk for, knee OA.

Methods

At the 60‐month visit of the Multicenter Osteoarthritis Study, men and women ages 55–84 years were asked about knee buckling in the past 3 months and whether they fell when a knee buckled. Falls and fall‐related injuries in the past 12 months and balance confidence were assessed at 60 and 84 months. Multivariate logistic regression was used to assess the association of knee buckling with falls and their consequences.

Results

A total of 1,842 subjects (59% women, mean ± SD age 66.9 ± 7.8 years, and body mass index 30.3 ± 5.7) were included. At 60 months 16.8% reported buckling and at 84 months 14.1% had recurrent (≥2) falls. Bucklers at 60 months had a 1.6‐ to 2.5‐fold greater odds of recurrent falls, fear of falling, and poor balance confidence at 84 months. Those who fell when a knee buckled at baseline had a 4.5‐fold, 2‐fold, and 3‐fold increased odds 2 years later of recurrent falls, significant fall injuries, and fall injuries that limited activity, respectively, and were 4 times more likely to have poor balance confidence.

Conclusion

Interventions that reduce knee buckling may help prevent falls, fall‐related injuries, and adverse psychological consequences of falls in persons with knee OA.