bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid sample preparation of dissolved inorganic carbon in natural waters using a headspace‐extraction approach for radiocarbon analysis by accelerator mass spectrometry
Authors: Gao Pan , Xu Xiaomei , Zhou Liping , Pack Mary A. , Griffin Sheila , Santos Guaciara M. , Southon John R. , Liu Kexin
Published: August 2016

We have established a high‐throughput headspace‐extraction method for the preparation of dissolved inorganic carbon (DIC) from water samples for radiocarbon (14C) analysis by accelerator mass spectrometry (AMS). Readily available septum‐sealed screw cap vials were used for sample processing. Headspace‐equilibrated gases with sample CO2 were transferred using a syringe and cryogenically purified on a vacuum line for graphitization and 14C‐AMS measurements in the Keck Carbon Cycle AMS facility at the University of California, Irvine (KCCAMS/UCI). Systematic investigations have shown that the extraction process does not introduce contaminants that could bias the 14C measurements and that the 14C results for standards are consistent with their consensus values. Large numbers of duplicate measurements have established a precision of 1.7‰ for modern samples with an average background of ~43,400 radiocarbon year for graphite target samples > 0.3 mg carbon. Seawater samples collected from Newport Beach, California, and processed using the headspace‐extraction method yielded 14C results in excellent agreement with published values obtained with conventional DIC stripping (≤ ± 2σ). The simplicity of our headspace‐extraction approach allows its easy adaptation/implementation to any isotope lab, as we demonstrate here by a series of tests carried out at Peking University, China (PKU). With this innovative method, just 30 mL seawater per sample is needed. Coupled with the sealed tube zinc reduction method, 15 water samples can be prepared and graphitized in 1 day.
A seawater filtration method suitable for total dissolved inorganic carbon and pH analyses
Authors: Bockmon Emily E. , Dickson Andrew G.
Published: August 2016

High biomass and heavy particle loads may interfere with carbonate chemistry analyses of samples from experimental aquaria and cultures used to investigate the impact of ocean acidification on organisms, as well as from biologically productive coastal regions. For such samples, a filtration method is needed that does not change the dissolved CO2 content, and consequently does not alter the total dissolved inorganic carbon and pH of the sample. Here, a filtration method is presented in which the sample seawater is pumped by a peristaltic pump through a replaceable 0.45 µm filter in a 50 mm polycarbonate filter holder and then into the sample bottle. Seawater samples of known carbonate composition were filtered to confirm that the filtration method did not alter the CO2 content, and compromise the subsequent sample analysis and data usefulness. Seawater samples with added phytoplankton concentrations in the range of 1–5 × 105 cells mL−1 were also filtered successfully. Finally, seawater with added biogenic CaCO3 was tested to prove that the method could successfully filter out such particles and produce dependable results. This approach will help to ensure more consistent and reliable carbonate chemistry measurements in coastal environments and from ocean acidification aquaria and cultures, by providing a well‐tested method for sample filtration.
A continuous flow isotope ratio mass spectrometry method for high precision determination of dissolved gas ratios and isotopic composition
Authors: Charoenpong Chawalit N. , Bristow Laura A. , Altabet Mark A.
Published: August 2016

Dissolved gas ratios and isotopic compositions provide essential information about the biological and physical mechanisms influencing N2, O2, and Ar in aquatic systems. Current methods available are either limited by overall cost, labor‐intensive sample collection and analysis, or insufficient precision. Here, we present a new highly accurate and robust method for sample collection and subsequent simultaneous measurement of the dissolved gas ratios (N2/Ar and O2/Ar) and isotopic compositions (δ15N2 and δ18O2) in seawater. The relatively simple sampling procedure using low cost materials enables collection of hundreds to more than a thousand discrete samples on a single research cruise. Samples can be preserved and stored at room temperature and maintain their integrity for many months. Laboratory analysis employs an on‐line extraction system coupled to a multi‐collector isotope ratio mass spectrometer (IRMS). A continuous flow of He carrier gas completely degasses the sample, and passes through the preparation and purification system before entering the IRMS for analysis. The use of this continuous He carrier permits short analysis times (less than 8 min per sample) as compared with current high‐precision methods. In addition to reference gases, calibration is achieved using air‐equilibrated water standards of known temperature and salinity. Assessment of reference gas injections, air equilibrated standards, as well as samples collected in the field shows the accuracy and precision of this new method to be equal to or better than current standard techniques.
Polarization properties of aerosol particles over western Japan:
classification, seasonal variation, and implications for air quality
Authors: Pan Xiaole , Uno Itsushi , Hara Yukari , Osada Kazuo , Yamamoto Shigekazu , Wang Zhe , Sugimoto Nobuo , Kobayashi Hiroshi , Wang Zifa
Published: August 2016

Abstract. Ground-based observation of the polarization properties of aerosol particles using a polarization optical particle counter (POPC) was made from 27 October 2013, to 31 December 2015, at a suburban site in the Kyushu area of Japan. We found that the depolarization ratio (DR, the fraction of s-polarized signal in the total backward light scattering signal) of aerosol particles showed prominent seasonal variability, with peaks in spring (0.21–0.23) and winter (0.19–0.23), and a minimum value (0.09–0.14) in summer. The aerosol compositions in both fine mode (aerodynamic diameter of particle, Dp  <  2.5 µm) and coarse mode (2.5 µm  <  Dp  <  10 µm), and the size-dependent polarization characteristics were analyzed for long-range transport dust particles, sea salt, and anthropogenic pollution-dominant aerosols. The DR value increased with increasing particle size, and DR  =  0.1 was a reliable threshold value to identify the sphericity of supermicron (Dp  >  1 µm) particles. Occurrence of substandard air quality days in Kyushu was closely related with mixed type (coexistence of anthropogenic pollutants and dust particles in the atmosphere), especially in winter and spring, indicating that dust events in the Asian continent played a key role in the cross-boundary transport of continental pollution. Backward trajectory analysis demonstrated that air masses originating from the western Pacific contained large amounts of spherical particles due to the influence of sea salt, especially in summer; however, for air masses from the Asian continent, the dependence of number fraction of spherical particles on air relative humidity was insignificant, indicating the predominance of less-hygroscopic substances (e.g., mineral dust), although the mass concentrations of anthropogenic pollutants were elevated.
Atmospheric aerosols in Rome, Italy: Sources, dynamics and spatial variations during two seasons
Authors: Struckmeier Caroline , Drewnick Frank , Fachinger Friederike , Gobbi Gian Paolo , Borrmann Stephan
Published: August 2016

Abstract. Investigations on atmospheric aerosols and their sources were performed during October/November 2013 and May/June 2014 subsequently in a suburban area of Rome (Tor Vergata) and in central Rome (near St. Peter's Basilica). During both years a Saharan dust advection event temporarily increased PM10 concentrations at ground level by approximately 10 µg m−3. Generally, during Oct/Nov the ambient aerosol was more strongly influenced by primary emissions, whereas higher relative contributions of secondary particles (sulphate, aged organic aerosol) were found during May/June. Absolute concentrations of anthropogenic emission tracers (e.g. NOx, CO2, particulate polyaromatic hydrocarbons, traffic-related organic aerosol) were generally higher at the urban location. Positive matrix factorisation was applied to the PM1 organic aerosol (OA) fraction of aerosol mass spectrometer (HR-ToF-AMS) data in order to identify different sources of primary OA (POA): traffic, cooking, biomass burning, and (local) cigarette smoking. While biomass burning OA was only found at the suburban site, where it accounted for the major fraction of POA (18–24 % of total OA), traffic and cooking were more dominant sources at the urban site. A particle type associated with cigarette smoke emissions, which is associated with a potential characteristic marker peak (m/z 84, C5H10N+, a nicotine fragment) in the mass spectrum, was only found in central Rome, where it was emitted in close vicinity to the measurement location. Regarding secondary OA, in Oct/Nov, only a very aged, regionally advected oxygenated OA was found, which contributed 42–53 % to the total OA. In May/June total oxygenated OA accounted for 56–76 % of the OA. Here also a fraction (18–26 % of total OA) of a fresher, less oxygenated OA of more local origin was observed. New particle formation events were identified from measured particle number concentrations and size distributions during May/June 2014 at both sites. While they were observed every day at the urban location, at the suburban location they were only found under favourable meteorological conditions, but independent of advection of the Rome emission plume. Particles from sources in the metropolitan area of Rome and particles advected from outside Rome contributed 42–70 % and 30–58 % to total measured PM1, respectively. Apart from the general aerosol characteristics, in this study the properties (e.g. emission strength) and dynamics (e.g. temporal behaviour) of each identified aerosol type is investigated in detail in order to provide a better understanding of the observed seasonal and spatial differences.
Temporal changes in photoreactivity of dissolved organic carbon and implications for aquatic carbon fluxes from peatlands
Authors: Pickard Amy E. , Heal Kate V. , McLeod Andrew R. , Dinsmore Kerry J.
Published: August 2016

Abstract. Aquatic systems draining peatland catchments receive a high loading of dissolved organic carbon (DOC) from the surrounding terrestrial environment. Whilst photo-processing is known to be an important process in the transformation of aquatic DOC, the drivers of temporal variability in this pathway are less well understood. In this study, laboratory irradiation experiments were conducted on water samples collected from two contrasting peatland aquatic systems in Scotland. The first system was a stream draining the Auchencorth Moss peatland with high DOC concentrations subject to strong seasonal and flow driven variability. The second was the low DOC reservoir, Loch Katrine, also situated in a catchment with a high percentage peat cover. Samples were collected monthly at both sites from May 2014 to May 2015 and from the stream system during two rainfall events. DOC concentrations, absorbance properties and fluorescence characteristics were measured to investigate characteristics of the photochemically labile fraction of DOC. CO2 and CO produced by irradiation were also measured to determine total photoproduction and intrinsic sample photoreactivity. Significant variation was seen in the photoreactivity of DOC between the two systems, with total irradiation induced changes typically two orders of magnitude greater at the high DOC stream site. This is attributed to longer water residence times in the reservoir rendering a higher proportion of the DOC recalcitrant to photo-processing. Rainfall events were identified as important in replenishing photoreactive material in the stream, with lignin phenol data (Ad:Alv,s and P:V) indicating mobilisation of fresh DOC derived from woody vegetation in the upper catchment. Using DOC-CO2 conversion data from irradiation experiments, we estimate that the contribution of Auchencorth Moss catchment to photo-induced aquatic CO2 production is up to 3.48 ± 2.02 kg CO2 yr−1. We have shown that peatland catchments produce significant volumes of aromatic DOC and that photoreactivity of this DOC is greatest in the headwaters, however an improved understanding of water residence times and DOC input-output along the source to sea aquatic pathway is required to determine the fate of peatland carbon.
Impacts of climate mitigation strategies in the energy sector on
global land use and carbon balance
Authors: Engström Kerstin , Lindeskog Mats , Olin Stefan , Hassler John , Smith Benjamin
Published: August 2016

Abstract. Reducing greenhouse gas emissions to limit climate change-induced damage to the global economy and secure the livelihoods of future generations requires ambitious mitigation strategies. The introduction of a global carbon tax on fossil fuels is tested here as a mitigation strategy to reduce atmospheric CO2 concentrations and radiative forcing. Taxation of fossil fuels potentially leads to changed composition of energy sources, including a larger relative contribution from bioenergy. Further, the introduction of a mitigation strategy reduces climate change-induced damage to the global economy, and thus can indirectly affect consumption patterns and investments in agricultural technologies and yield enhancement. Here we assess the implications of changes in bioenergy demand as well as the indirectly caused changes in consumption and crop yields for global and national cropland area and terrestrial biosphere carbon balance. We apply a novel integrated assessment modelling framework, combining a climate-economy model, a socio-economic land-use model and an ecosystem model. We develop reference and mitigation scenarios based on the Shared Socio-economic Pathways (SSPs) framework. Taking emissions from the land-use sector into account, we find that the introduction of a global carbon tax on the fossil fuel sector is an effective mitigation strategy only for scenarios with low population development and strong sustainability criteria (SSP1 "Taking the green road"). For scenarios with high population growth, low technological development and bioenergy production the high demand for cropland causes the terrestrial biosphere to switch from being a carbon sink to a source by the end of the 21st century.
Figures to the article "Assimilation of mathematical knowledge using Maple" on pages 321-331. (color plate)
Authors: Kovács Zoltán , Kozma László
Published: August 2016

Color plate
The efficiency of written final exam questions in mathematics based on voluntary data reports, 2012–2015
Authors: Csapodi Csaba , Koncz Levente
Published: August 2016

The efficiency of each question in the mathematics written final exam is not recorded by the institutions organizing the graduation exam. In order to overcome this deficiency the committee of final exams in mathematics and the Hungarian Educational Authority ask schools to send – beyond the total marks obtained on the paper – the scores of each question of all individual candidates to the Authority every year since 2012. Because a high proportion of schools complied with this request between 2012 and 2015, the researchers were provided valuable information for a deeper analysis on the effectiveness of exams. In this paper we have carried out an analysis of the efficiency of questions set in the written examination papers both on the intermediate and on the higher level in the last four years, on the basis of these voluntary data reports.
Bridging English Language Learner Achievement Gaps through Effective Vocabulary Development Strategies
Authors: Gibson Charles
Published: August 2016

Despite a well-documented history of immigration in the United States of America and rise in population of students that speak a language other than English, academic achievement gaps between English Language Learners and their native English language speaking counterparts from Grades Pre-Kindergarten through the college/university level still exist. This research paper conducted a review of philosophical and scholarly literature which displayed evidence that vocabulary development is a major section that educators should consider focusing for to better achievement with English as Second Language students. Implementing educational practices that promote high-frequency vocabulary learning, using teaching approaches that include cognitive and metacognitive strategy, along with incorporating computer-based instruction into language development activities were found to be effective strategies. The discussion of the identified strategies presented in the present review of literature concludes with recommendations for administrators and education professionals serving English Language Learners and English as Second Language students in various learning environments.
Teaching Vocabulary with Graphic Novels
Authors: Basal Ahmet , Aytan Talat , Demir Ibrahim
Published: August 2016

Mastery of idiomatic expressions by foreign language learners is often equated with the fluency of native speakers of that language. However, learning these idiomatic expressions is one of the significant problems experienced by learners. The present quasi-experimental study conducted over four weeks in the ELT department of a Turkish university aims to investigate the effectiveness of teaching idioms via graphic novels compared to teaching them via traditional activities. The most frequent and useful forty figurative idioms from the Michigan Academic English Spoken Corpus (MICASE) were used in a script and the script was converted to a graphic novel with the use of a computer software. The results revealed that participants in the experimental group who had learned idioms through the graphic novel performed significantly better on the post-test, indicating the efficiency of the graphic novel in vocabulary teaching. The study also offers recommendations for the use of graphic novels in the teaching of vocabulary.
Exploring Emotional Intelligence and Academic Performance of Filipino University Academic Achievers
Authors: Bance Lucila O. , B. Acopio John Ray
Published: August 2016

The responsibility of academic institutions to produce holistically developed individuals puts compounded pressure on the school administrators to raise students’ achievement. While most learning institutions put a premium on readying its learners in attaining scholastic success, it is quite apparent how most Philippine schools neglected to put an ample attention to one’s emotional and social growth. This current study utilized a descriptive-correlational design—with a randomized sample of 203 university academic achievers between ages of 16 to 21—to generate relationships among factors derived from Emotional Quotient-i: Youth Version (EQ-i:YV) and academic performance as measured by General Pointed Average (GPA). Pearson’s correlations suggested that the overall emotional intelligence has significant positive associations with intrapersonal, interpersonal, stress management, adaptability and general mood scales while overall emotional intelligence and its composite scales are related to academic performance. Thus the findings affirmed the claim that the more the academic achievers become emotional-social intelligent, the higher their tendency to exude academic prowess. This study further highlights the potential implications of emotional intelligence in educational progress and academic success; hence emotional intelligence-based activities should be integrated in higher education curriculum.
The relationship between problem size and fixation patterns during addition, subtraction, multiplication, and division
Authors: Curtis Evan T. , Huebner Matthew G. , LeFevre Jo-Anne
Published: August 2016

Eye-tracking methods have only rarely been used to examine the online cognitive processing that occurs during mental arithmetic on simple arithmetic problems, that is, addition and multiplication problems with single-digit operands (e.g., operands 2 through 9; 2 + 3, 6 x 8) and the inverse subtraction and division problems (e.g., 5 – 3; 48 ÷ 6). Participants (N = 109) solved arithmetic problems from one of the four operations while their eye movements were recorded. We found three unique fixation patterns. During addition and multiplication, participants allocated half of their fixations to the operator and one-quarter to each operand, independent of problem size. The pattern was similar on small subtraction and division problems. However, on large subtraction problems, fixations were distributed approximately evenly across the three stimulus components. On large division problems, over half of the fixations occurred on the left operand, with the rest distributed between the operation sign and the right operand. We discuss the relations between these eye tracking patterns and other research on the differences in processing across arithmetic operations.
Fútbol global e identidades nacionales en 1925: la gira del Club Atlético Boca Juniors en España a través de su impacto en la prensa
Authors: Simón Juan Antonio
Published: August 2016

What role did football play during the dictatorship of Primo de Rivera (1923-1930) in Spain? This is one of the questions that this article attempts to resolve. Its objective is to present the impact of the first visit to Spain on the part of an Argentine club, the Boca Juniors Athletic Club, as reported in the Spanish press in 1925. At the methodological level, a review was done of the general bibliography and of the main Spanish magazines and newspapers, both in terms of sports and general information. It demonstrates, as its general conclusion, the interest that the Boca Juniors’ tour sparked among Spanish and Argentinian fans alike, showing this to be an occasion for asserting both national identity and global relations through football.
Cultura física, performance atlética e higiene de la nación. El surgimiento de la medicina deportiva en Argentina (1930-1940)
Authors: Reggiani Andrés Horacio
Published: August 2016

This article analyzes the formation of a sports-medicine field in Argentina in the decades of the 1930s and 1940s. This process is examined from three perspectives: in the first place, it is situated within the context of the diffusion of sports and growing interest in the scientific study of athletic performance. In the second place, it considers the axes around which the debate on physical culture was articulated in Argentina during the period between the wars, with special attention paid to the impact the recreational revolution produced among the medical elite. Finally, in the third place, it explores the process that led to the creation of the present International Federation of Sports Medicine and its repercussions in Argentina and Latin America in general. Combining approaches to the sociocultural history of sports and the circulation of scientific knowledge regarding the body, the analysis emphasizes the constitution of sports medicine as a professional field of applied science in a context of decline of demographic growth, Taylorist concerns about human capital, democratization of consumption and advance of the state.
El agravio moral como resorte de la acción colectiva
Authors: Meneses Reyes Marcela
Published: August 2016

The objective of this article consists of showing that the sentiment of moral grievance, while it does not determine or completely explain collective action, does appear repeatedly as one of the arguments put forward by actors mobilized in the defense of their own judgments of what they consider to be just or unjust, in opposition to those acts or actors by whom they consider themselves to have been aggrieved, and from whom they demand restitution for the damage inflicted. Such was the case of the social movement that took place in Oaxaca (Mexico) in 2006: a conflict which began as a teachers’ protest and then turned into one of the most important organizational popular fronts of the new century in Mexico. In general terms, it proposes considering morality and the values that emanate therefrom, as well as human experience, to be significant elements for the understanding of collective action and of social movements.
Long‐term effectiveness of initiating non‐nucleoside reverse transcriptase inhibitor‐ versus ritonavir‐boosted protease inhibitor‐based antiretroviral therapy: implications for first‐line therapy choice in resource‐limited settings
Authors: Lima Viviane D , Hull Mark , McVea David , Chau William , Harrigan P Richard , Montaner Julio SG
Published: August 2016

Introduction

In many resource‐limited settings, combination antiretroviral therapy (cART) failure is diagnosed clinically or immunologically. As such, there is a high likelihood that patients may stay on a virologically failing regimen for a substantial period of time. Here, we compared the long‐term impact of initiating non‐nucleoside reverse transcriptase inhibitor (NNRTI)‐ versus boosted protease inhibitor (bPI)‐based cART in British Columbia (BC), Canada.

Methods

We followed prospectively 3925 ART‐naïve patients who started NNRTIs (N=1963, 50%) or bPIs (N=1962; 50%) from 1 January 2000 until 30 June 2013 in BC. At six months, we assessed whether patients virologically failed therapy (a plasma viral load (pVL) >50 copies/mL), and we stratified them based on the pVL at the time of failure ≤500 versus >500 copies/mL. We then followed these patients for another six months and calculated their probability of achieving subsequent viral suppression (pVL <50 copies/mL twice consecutively) and of developing drug resistance. These probabilities were adjusted for fixed and time‐varying factors, including cART adherence.

Results

At six months, virologic failure rates were 9.5 and 14.3 cases per 100 person‐months for NNRTI and bPI initiators, respectively. NNRTI initiators who failed with a pVL ≤500 copies/mL had a 16% higher probability of achieving subsequent suppression at 12 months than bPI initiators (0.81 (25th–75th percentile 0.75–0.83) vs. 0.72 (0.61–0.75)). However, if failing NNRTI initiators had a pVL >500 copies/mL, they had a 20% lower probability of suppressing at 12 months than pVL‐matched bPI initiators (0.37 (0.29–0.45) vs. 0.46 (0.38–0.54)). In terms of evolving HIV drug resistance, those who failed on NNRTI performed worse than bPI in all scenarios, especially if they failed with a viral load >500 copies/mL.

Conclusions

Our results show that patients who virologically failed at six months on NNRTI and continued on the same regimen had a lower probability of subsequently achieving viral suppression and a higher chance of evolving HIV drug resistance. These results suggest that improving access to regular virologic monitoring is critically important, especially if NNRTI‐based cART is to remain a preferred choice for first‐line therapy in resource‐limited settings.
Sonography and Transthoracic Echocardiography for Diagnosis of Systemic Cardiovascular Metastatic Tumor Thrombi
Authors: Wang Jiong , Cheng Yi , Lee Yueh Z. , Wang Yongmei , Zheng Ye , Dong Ran , Lai Yongqiang , Tang Xiaobin , Yang Yaoguo , Wang Sheng , He Nan , Jia Yunfeng , Cheng Wei , Liu Dan , Wang Xiaona , Zhang Chun
Published: August 2016

Sonography and transthoracic echocardiography (TTE) are seldom used for assessment of metastatic tumor thrombi in the cardiovascular system in routine clinical practice. We performed this retrospective study to evaluate the combination of sonography with TTE for diagnosis of metastatic tumor thrombi in heart and systemic vessels. Vascular, abdominal, pelvic, and small‐part sonography was applied in 18 patients, and TTE was conducted simultaneously in 14 patients. Tumor thrombi invaded into the inferior vena cava system in 12 patients, superior vena cava system in 5 patients, and aorta in 1 patient; they extended to the right cardiac chambers in 11 patients. Six patients had diagnoses by pathologic examination. The primary neoplasms were identified by conventional imaging in 17 patients. The morphologic and echogenic characteristics of the tumor thrombi were diverse and depended on their original tumors. The thrombi were either contiguous or discrete from the original tumors. The neoplastic vascularity of the thrombi and the invasive extension were the primary characteristics that distinguished them from bland thrombi. Simultaneous application of sonography and TTE is a feasible way to comprehensively evaluate cardiovascular metastatic tumor thrombi in most patients.
Geologic context of recurring slope lineae in Melas and Coprates Chasmata, Mars
Authors: Chojnacki Matthew , McEwen Alfred , Dundas Colin , Ojha Lujendra , Urso Anna , Sutton Sarah
Published: August 2016

One of the major Mars discoveries of recent years is the existence of recurring slope lineae (RSL), which suggests that liquid water occurs on or near the surface of Mars today. These dark and narrow features emerge from steep, rocky exposures and incrementally grow, fade, and reform on a seasonal basis and are detected in images from the High Resolution Imaging Science Experiment camera. RSL are known to occur at scattered midlatitude and equatorial sites with little spatial connection to one another. One major exception is the steep, low‐albedo slopes of Melas and Coprates Chasmata, in Valles Marineris where RSL are detected among diverse geologic surfaces (e.g., bedrock and talus) and landforms (e.g., inselbergs and landslides). New images show topographic changes including sediment deposition on active RSL slopes. Midwall locations in Coprates and Melas appear to have more areally extensively abundant RSL and related fans as compared with other RSL sites found on Mars. Water budget estimates for regional RSL are on the order of 105 to 106 m3 of fluid, for depths of 10 to 100 mm, and suggest that a significant amount of near‐surface water might be present. Many RSL are concentrated near local topographic highs, such as ridge crests or peaks, which is challenging to explain via groundwater or ice without a recharge mechanism. Collectively, results provide additional support for the notion that significant amounts of near‐surface water can be found on Mars today and suggest that a widespread mechanism, possibly related to the atmosphere, is recharging RSL sources.
LPMLE3: A novel 1‐D approach to study water flow in streambeds using heat as a tracer
Authors: Schneidewind U. , van Berkel M. , Anibas C. , Vandersteen G. , Schmidt C. , Joris I. , Seuntjens P. , Batelaan O. , Zwart H. J.
Published: August 2016

We introduce LPMLE3, a new 1‐D approach to quantify vertical water flow components at streambeds using temperature data collected in different depths. LPMLE3 solves the partial differential equation for coupled water flow and heat transport in the frequency domain. Unlike other 1‐D approaches it does not assume a semi‐infinite halfspace with the location of the lower boundary condition approaching infinity. Instead, it uses local upper and lower boundary conditions. As such, the streambed can be divided into finite subdomains bound at the top and bottom by a temperature‐time series. Information from a third temperature sensor within each subdomain is then used for parameter estimation. LPMLE3 applies a low order local polynomial to separate periodic and transient parts (including the noise contributions) of a temperature‐time series and calculates the frequency response of each subdomain to a known temperature input at the streambed top. A maximum‐likelihood estimator is used to estimate the vertical component of water flow, thermal diffusivity, and their uncertainties for each streambed subdomain and provides information regarding model quality. We tested the method on synthetic temperature data generated with the numerical model STRIVE and demonstrate how the vertical flow component can be quantified for field data collected in a Belgian stream. We show that by using the results in additional analyses, nonvertical flow components could be identified and by making certain assumptions they could be quantified for each subdomain. LPMLE3 performed well on both simulated and field data and can be considered a valuable addition to the existing 1‐D methods.
An upscaling procedure for fractured reservoirs with embedded grids
Authors: Fumagalli Alessio , Pasquale Luca , Zonca Stefano , Micheletti Stefano
Published: August 2016

Upscaling of geological models for reservoir simulation is an active and important area of research. In particular, we are interested in reservoirs where the rock matrix exhibits an intricate network of fractures, which usually acts as a preferential path to the flow. Accounting for fractures' contribution in the simulation of a reservoir is of paramount importance. Here we have focused on obtaining effective parameters (e.g., transmissibility) on a 3‐D computational grid on the reservoir scale, which account for the presence, at a finer spatial scale, of fractures and a network of fractures. We have essentially followed the idea illustrated in Karimi‐Fard et al. (2006), yet this work has some notable aspects of innovation in the way the procedure has been implemented, and in its capability to consider rather general corner‐point grids, like the ones normally used in reservoir simulations in the industry, and complex and realistic fracture networks, possibly not fully connected inside the coarse cells. In particular, novel contribution is the employment of an Embedded Discrete Fracture Model (EDFM) for computing fracture‐fracture and matrix‐fracture transmissibilities, with a remarkable gain in speedup. The output is in the form of transmissibility that, although obtained by considering single‐phase flow, can be used for coarse‐scale multiphase reservoir simulations, also via industrial software, such as Eclipse, Intersect, or GPRS. The results demonstrate the effectiveness and computational efficiency of the numerical procedure which is now ready for further testing and industrialization.
Land‐surface controls on near‐surface soil moisture dynamics: Traversing remote sensing footprints
Authors: Gaur Nandita , Mohanty Binayak P.
Published: August 2016

In this new era of remote‐sensing based hydrology, a major unanswered question is how to incorporate the impact of land‐surface based heterogeneity on soil moisture dynamics at remote sensing scales. The answer to this question is complicated since (1) soil moisture dynamics that vary with support, extent, and spacing scales are dependent on land‐surface based heterogeneity and (2) land‐surface based heterogeneity itself is scale‐specific and varies with hydroclimates. Land‐surface factors such as soil, vegetation, and topography affect soil moisture dynamics by redistributing the available soil moisture on the ground. In this study, we determined the contribution of these biophysical factors to redistribution of near‐surface soil moisture across a range of remote sensing scales varying from an (airborne) remote sensor footprint (1.6 km) to a (satellite) footprint scale (25.6 km). Two‐dimensional nondecimated wavelet transform was used to extract the support scale information from the spatial signals of the land‐surface and soil moisture variables. The study was conducted in three hydroclimates: humid (Iowa), subhumid (Oklahoma), and semiarid (Arizona). The dominance of soil on soil moisture dynamics typically decreased from airborne to satellite footprint scales whereas the influence of topography and vegetation increased with increasing support scale for all three hydroclimates. The distinct effect of hydroclimate was identifiable in the soil attributes dominating the soil moisture dynamics. The near‐surface soil moisture dynamics in Arizona (semiarid) can be attributed more to the clay content which is an effective limiting parameter for evaporation whereas in Oklahoma (humid), sand content (limiting parameter for drainage) was the dominant soil attribute. The findings from this study can provide a deeper understanding of the impact of heterogeneity on soil moisture dynamics and the potential improvement of hydrological models operating at footprints' scales.
The effect of the water tariff structures on the water consumption in Mallorcan hotels
Authors: Deyà‐Tortella Bartolomé , Garcia Celso , Nilsson William , Tirado Dolores
Published: August 2016

Tourism increases water demand, especially in coastal areas and on islands, and can also cause water shortages during the dry season and the degradation of the water supply. The aim of this study is to evaluate the impact of water price structures on hotel water consumption on the island of Mallorca (Spain). All tourist municipalities on the island use different pricing structures, such as flat or block rates, and different tariffs. This exogenous variation is used to evaluate the effect of prices on water consumption for a sample of 134 hotels. The discontinuity of the water tariff structure and the fixed rate, which depends on the number of hotel beds, generate endogeneity problems. We propose an econometric model, an instrumental variable quantile regression for within artificial blocks transformed data, to solve both problems. The coefficients corresponding to the price variables are not found to be significantly different from zero. The sign of the effect is negative, but the magnitude is negligible: a 1% increase in all prices would reduce consumption by an average of only 0.024%. This result is probably due to the small share of water costs with respect to the total hotel operational costs (around 4%). Our regression model concludes that the introduction of water‐saving initiatives constitutes an effective way to reduce consumption.
How does reach‐scale stream‐hyporheic transport vary with discharge? Insights from rSAS analysis of sequential tracer injections in a headwater mountain stream
Authors: Harman C. J. , Ward A. S. , Ball A.
Published: August 2016

The models of stream reach hyporheic exchange that are typically used to interpret tracer data assume steady‐flow conditions and impose further assumptions about transport processes on the interpretation of the data. Here we show how rank Storage Selection (rSAS) functions can be used to extract “process‐agnostic” information from tracer breakthrough curves about the time‐varying turnover of reach storage. A sequence of seven slug injections was introduced to a small stream at base flow over the course of a diel fluctuation in stream discharge, providing breakthrough curves at discharges ranging from 0.7 to 1.2 L/s. Shifted gamma distributions, each with three parameters varying stepwise in time, were used to model the rSAS function and calibrated to reproduce each breakthrough curve with Nash‐Sutcliffe efficiencies in excess of 0.99. Variations in the fitted parameters over time suggested that storage within the reach does not uniformly increase its turnover rate when discharge increases. Rather, changes in transit time are driven by both changes in the average rate of turnover (external variability) and changes in the relative rate that younger and older water contribute to discharge (internal variability). Specifically, at higher discharge, the turnover rate increased for the youngest part of the storage (corresponding to approximately 5 times the volume of the channel), while discharge from the older part of the storage remained steady, or declined slightly. The method is shown to be extensible as a new approach to modeling reach‐scale solute transport that accounts for the time‐varying, discharge‐dependent turnover of reach storage.
Elicitation
Authors: Wolfson Lara J. , Bousquet Nicolas
Published: August 2016

This article makes a survey of the foundations, methodologies, and issues linked to the process of prior elicitation in Bayesian analysis.
Redundancy Analysis
Authors: DeSarbo Wayne S. , Hwang Heungsun , Jedidi Kamel
Published: August 2016

The interrelationships between two sets of measurements made on the same subjects can be studied by canonical correlation. The canonical correlation is the maximum correlation between linear functions or canonical factors of two sets of variables. An alternative pair of statistics to investigate the interrelationships between two sets of variables are the redundancy indices. A redundancy index is an indication of the average proportion of variance in the variables in one set that is reproducible from the variables in the other set. Unlike canonical correlation, redundancy indices are non‐symmetric in that a measure can be calculated for each set of variables (predictor and criterion) and need not be equal to each other. A method of extracting factors that maximize redundancy, as opposed to canonical correlation, has been developed as well as various extensions of this methodology. More recently, extended redundancy analysis has been developed to generalize redundancy analysis to investigate asymmetric or directional associations among more than two sets of variables, analogous to generalized canonical correlation analysis. A sports marketing application is provided examining the relationship between the different ways consumers/fans follow their college football team and their various attitudes, opinions, and lifestyles (i.e.,
psychographics
) regarding sports.
Wildlife Ecology
Authors: Bowyer R. Terry , Stewart Kelley M. , Monteith Kevin L. , Aho Ken A.
Published: August 2016

Studies in wildlife ecology often use descriptive and inferential methods that reflect characteristics of data and the practical needs of wildlife managers. The discipline generally emphasizes population rather than individual features or broader ecosystem processes; this approach is reflected in quantitative methods developed and adopted by wildlife ecologists. Modern wildlife ecology considers both the management and conservation of animals and also includes theoretical studies and perspectives related to wildlife‐associated phenomena. The discipline has become increasingly quantitative over time and often employs capture–recapture methods to estimate population size, survival, and other life‐history characteristics. Quantitative methods used to study wildlife include, but are not limited to, estimates of abundance, population‐viability analysis, home‐range estimation, movements, migration, spatial distributions, and landscape metrics. Radiotelemetry is widely used to conduct research on wildlife. Habitat selection, stable isotope analysis, genetics, and behavioral sampling also play important roles in studies of wildlife.
Graphics for Large Data Sets
Authors: Theus Martin
Published: August 2016

Large data sets face many challenges. While classical statistical theory often fails for larger data sets, graphics seem to be more robust against growing data set sizes. Nonetheless, graphics face certain challenges for large data sets as well; some of them can be cured successfully and some call for completely new graphical representations. Generally, interactivity can help dramatically when working with graphs of large data.
In Situ Bond Modulation of Graphitic Carbon Nitride to Construct p–n Homojunctions for Enhanced Photocatalytic Hydrogen Production
Authors: Liu Guigao , Zhao Guixia , Zhou Wei , Liu Yanyu , Pang Hong , Zhang Huabin , Hao Dong , Meng Xianguang , Li Peng , Kako Tetsuya , Ye Jinhua
Published: August 2016

Graphitic carbon nitride (g‐C3N4) has recently emerged as an attractive photocatalyst for solar energy conversion. However, the photocatalytic activities of g‐C3N4 remain moderate because of the insufficient solar‐light absorption and the fast electron–hole recombination. Here, defect‐modified g‐C3N4 (DCN) photocatalysts, which are easily prepared under mild conditions and show much extended light absorption with band gaps decreased from 2.75 to 2.00 eV, are reported. More importantly, cyano terminal CN groups, acting as electron acceptors, are introduced into the DCN sheet edge, which endows the DCN with both n‐ and p‐type conductivities, consequently giving rise to the generation of p–n homojunctions. This homojunction structure is demonstrated to be highly efficient in charge transfer and separation, and results in a fivefold enhanced photocatalytic H2 evolution activity. The findings deepen the understanding on the defect‐related issues of g‐C3N4‐based materials. Additionally, the ability to build homojunction structures by the defect‐induced self‐functionalization presents a promising strategy to realize precise band engineering of g‐C3N4 and related polymer semiconductors for more efficient solar energy conversion applications.
Identification and Mitigation of a Critical Interfacial Instability in Perovskite Solar Cells Employing Copper Thiocyanate Hole‐Transporter
Authors: Liu Jiewei , Pathak Sandeep K. , Sakai Nobuya , Sheng Rui , Bai Sai , Wang Zhiping , Snaith Henry J.
Published: August 2016

Metal halide perovskites have emerged as one of the most promising materials for photovoltaics (PVs), with power conversion efficiency of over 22% already demonstrated. In order to compete with traditional crystalline silicon PV, cost and stability are equally important issues that need to be considered besides efficiency. Copper thiocyanate (CuSCN) is an interesting candidate to be used as an inexpensive, thermally stable p‐type charge conducting material in perovskite solar cells. Here, we report 13% efficient perovskite solar cells employing CuSCN as the hole‐transport material. We compare the stability of cells employing CuSCN with those employing the archetypical organic hole‐transporter 2,2′,7,7′‐Tetrakis (N,N‐di‐p‐methoxyphenyl‐amine) 9,9′‐Spirobifluorene (Spiro‐OMeTAD), under elevated temperature in ambient atmosphere. Surprisingly, we find that the devices employing CuSCN degrade faster under elevated temperatures than the devices employing Spiro‐OMeTAD. We discover that an interfacial degradation mechanism occurs at the heterojunction between the perovskite absorber and the CuSCN, even in a dry nitrogen atmosphere, identifying the presence of a critical instability. Interestingly, with the additional coating of the completed cells with a thin film of insulating poly(methyl methacrylate) (PMMA), functioning as a rudimentary “on‐cell” encapsulation, we significantly alleviate this issue and deliver efficient perovskite solar cells which survive for more than 1000 hours at 85 °C in air with only 25% degradation in performance. Beyond identifying a critical area to address in order to enable CuSCN to be useful for long term operation in perovskite solar cells, our findings indicate that the role of the “encapsulant” is to both keep the environment out, and keep degradation products within the cell.
Controllable Formation of Nanofilaments in Resistive Memories via Tip‐Enhanced Electric Fields
Authors: Shin Keun‐Young , Kim Youngjin , Antolinez Felipe V. , Ha Jeong Sook , Lee Sang‐Soo , Park Jong Hyuk
Published: August 2016

Resistive random access memory (ReRAM) has a great potential to be the next‐generation non‐volatile memory device. However, the random nucleation and growth of conductive filaments (CFs) in ReRAM causes the low reliability in switching behaviors, leading to difficulties in its practical application. This study demonstrates that manipulating electric fields in ReRAM via a structured electrode can provide the controllable formation of CFs. Ag pyramids that have a high‐quality tip prepared via the template‐stripping method generate highly enhanced electric fields at the tip. Because the tip‐enhanced electric fields can facilitate the ionization of Ag atoms and their migration along the electric fields, the nucleation and growth of CFs occurs predominantly at the tip. The CFs in ReRAM are directly observed using electron microscopy and it is confirmed that the CFs are formed only at the tip. The resulting ReRAM exhibits low and reliable SET/RESET voltages (0.48 V ± 0.02 V and 0.15 V ± 0.06 V, respectively). Moreover, its endurance and retention time are highly improved, compared to those devices that are based on conventional geometry. Thus, this approach can encourage creating high‐performance ReRAM.