bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantifying nitrogen losses in oil palm plantations: models and challenges
Authors: Pardon Lénaïc , Bessou Cécile , Saint-Geours Nathalie , Gabrielle Benoît , Khasanah Ni’matul , Caliman Jean-Pierre , Nelson Paul N.
Published: May 2016

Abstract. Oil palm is the most rapidly expanding tropical perennial crop. Its cultivation raises environmental concerns, notably related to the use of nitrogen (N) fertilisers and associated pollution and greenhouse gas emissions. While numerous and diverse models exist to estimate N losses from agriculture, very few are available for tropical perennial crops. Moreover, there has been no critical analysis of the performances of existing models in the specific context of tropical perennial cropping systems. We assessed the capacity of 11 models and 29 sub-models to estimate N losses in a typical oil palm plantation over a 25-year-growth cycle, through leaching and runoff, and emissions of NH3, N2, N2O, and NOx. Estimates of total N losses were very variable, ranging from 21 to 139 kg N ha−1 yr−1. On average, 31 % of the losses occurred during the first three years of the cycle. Leaching comprised about 80 % of the losses. Based on a comprehensive Morris sensitivity analysis, the most influential variables were soil clay content, rooting depth and oil palm N uptake. We also compared model estimates with published field measurements. Many challenges remain to model more accurately processes related to the peculiarities of perennial tropical crop systems such as oil palm.
Optimal numerical solvers for transient simulations of ice flow using the Ice Sheet System Model (ISSM)
Authors: Habbal Feras , Larour Eric , Rignot Eric , Borstad Christopher P. , Seroussi Helene , Morlighem Mathieu
Published: May 2016

Abstract. Identifying fast and robust numerical solvers is a critical issue that needs to be addressed in order to improve projections of polar ice sheets evolving in a changing climate. This work evaluates the impact of using sophisticated numerical solvers for transient ice flow simulations using the NASA-JPL/UCI Ice Sheet System Model (ISSM). We identify optimal numerical solvers by testing them on a commonly used ice flow benchmark test, the Ice Sheet Model Intercomparison Project for Higher-Order ice sheet Models (ISMIP-HOM) Experiment F. Three types of analyses are considered: mass transport, horizontal stress balance, and vertical stress balance. A broad suite of solvers is tested, ranging from direct sparse solvers to preconditioned iterative methods. The results of the fastest solvers for each analysis type are ranked based on their scalability across mesh size for each basal sliding conditions specified in Experiment F. We find that the fastest iterative solvers are ~1.5–100 times faster than the default direct solver used in ISSM with speed-ups improving rapidly with increased mesh resolution. We provide a set of recommendations for users in search of efficient solvers to use for transient ice flow simulations, enabling higher-resolution meshes and faster turnaround time. The end result will be improved transient simulations for short-term, highly resolved forward projections (10–100 year time scale) and also improved long-term paleo-reconstructions using higher-order representation of stresses in the ice. This analysis will also enable a new generation of comprehensive uncertainty quantification assessments of forward sea-level rise projections, which rely heavily on ensemble or sampling approaches that are inherently expensive.
Physically-based distributed hydrological model calibration based on a short period of streamflow data: case studies in two Chinese basins
Authors: Sun Wenchao , Wang Yuanyuan , Cui Xingqi , Yu Jingshan , Zuo Depeng , Xu Zongxue
Published: May 2016

Abstract. Physically-based distributed hydrological models are widely used for hydrological simulations in various environments. However, as with conceptual models, they are limited in data-sparse basin by the lack of streamflow data for calibration. Short periods of observational data (less than 1 year) may be obtained from the fragmentary historical records of past-existed gauging stations or from temporary gauging during field surveys, which might be of values for model calibration. This study explored how the use of limited continuous daily streamflow data might support the application of a physically-based distributed model in data-sparse basins. The influence of the length of observation period on the calibration of the widely applied Soil and Water Assessment Tool model was evaluated in two Chinese basins with differing climatic and geophysical characteristics. The evaluations were conducted by comparing calibrations based on short periods of data with calibrations based on data from a 3-year period, which were treated as benchmark calibrations for the two basins. To ensure the differences in the model simulations solely come from differences in the calibration data, the Generalized Likelihood Uncertainty Analysis scheme was employed for the automatic calibration and uncertainty analysis. In both basins, contrary to the common understanding of the need for observations over a period of several years, data records with lengths of less than 1 year were shown to calibrate the model effectively, i.e. performances similar to the benchmark calibrations were achieved. The model of wet Jinjiang Basin could be effectively calibrated using a shorter data record (1 month), compared with the arid Heihe Basin (6 months). Even though the two basins are very different, the results demonstrated that data from the wet season and wetter years performed better that data from the dry season and drier year. The results of this study demonstrated that short periods of observations could be a promising solution to the problem of calibration of physically-based distributed hydrological models in data-sparse basins and further researches similar to this study are required to gain more general understandings about the optimum number of observations needed for calibration when such model are applied to real data-sparse basins.
Wind tunnel tests with combined pitch and free-floating flap control: Data-driven iterative feedforward controller tuning
Authors: Navalkar S. T. , Bernhammer L. O. , Sodja J. , van Solingen E. , van Kuik G. A. M. , van Wingerden J.-W.
Published: May 2016

Abstract. Wind turbine load alleviation has traditionally been addressed in literature using either full-span pitch control, which has limited bandwidth, or trailing-edge flap control, which typically shows low control authority due to actuation constraints. This paper combines both methods, and demonstrates the feasibility and advantages of such a combined control strategy on a scaled prototype in a series of wind tunnel tests. The pitchable blades of the test turbine are instrumented with free-floating flaps close to the tip, designed such that they aerodynamically magnify the low stroke of high-bandwidth actuators. The additional degree of freedom leads to aeroelastic coupling with the blade flexible modes. The inertia of the flaps was tuned such that instability occurs just beyond the operational envelope of the wind turbine; the system can however be stabilised using collocated closed-loop control. A feedforward controller is shown capable of significant reduction of the deterministic loads of the turbine. Iterative feedforward tuning, in combination with a stabilising feedback controller, is used to optimise the controller online in an automated manner, to maximise load reduction. Since the system is non-linear, the controller gains vary with wind speed; this paper also shows that iterative feedforward tuning is capable of generating the optimal gain schedule online.
Innovative Approach in Total HIP Arthroplasty: Supercapsular Percutaneously-Assisted
Authors: Cardenas-Nylander Carlomagno , Bellotti Vittorio , Astarita Emanuele , Moya Gomez Esther , Fernandez Manuel Ribas
Published: May 2016

Introduction

There is widespread trend in total hip replacement to limit soft tissue damage. New approaches that respect the capsule and ligaments has been recently reported. The potential advantages of this approach is to improve short-term results in terms of stability, pain, length of stay, transfusions and complications.

Methods

From October 2015 to March 2016 the two senior authors performed 21 hips using the Superpath® technique, the measured variables included age, sex, operative time, acetabular inclination, pain assessment using visual analogue scale at 24 hours, need for transfusion, length of stay and complications. Surgical technique is described.

Results

10 women and 11 men with a mean age of 56.57 (35-74) years. Average operating time was 102.85 (80-130) minutes. The mean acetabular inclination was 44.05 (26-60) degrees. The visual analogue scale (VAS) at 24 hours of the procedure was 2.38, standard deviation (SD) 0.9. The length of stay was on average 4.04 days 1.4 days shorter when compared with a cohort of patients treated using standard posterolateral. All patients were discharged to home. Two patients required transfusion, and in one patient with a calcar crack, crutches for 8 weeks were instructed. No patients were readmitted.

Discussion

The new generation of hip approaches have a strong anatomical basis, hip capsule preservation is a revolutionary concept, it ensures anatomical restoration, length and offset near to native joint. The Superpath® potentially minimises morbidity, reducing transfusion rates, allowing rapid recovery, shortening hospital stay and could save a significant cost to the healthcare system.
Reconstruction of Nonrepairable Acetabular Labral Tears with Allografts: Mid-Term Results
Authors: Moya Esther , Ribas Manuel , Natera Luis , Cardenas Carlomagno , Bellotti Vittorio , Astarita Emanuele
Published: May 2016

Background

Many labral tears are nonrepairable. For these cases, labral reconstruction procedures may be considered in order to restore the joint fluid seal and prolong hip longevity.

Aims

The aim of this study was to describe the clinical and functional outcomes of a series of cases with nonrepairable labral tears that underwent labral reconstruction with tendon allografts. The hypothesis was that labral reconstruction would provide good clinical outcomes.

Method

A cohort of 20 patients with nonrepairable labral tears, which underwent to labral grafting mainly by means of arthroscopic assisted anterior mini-open approach, were included in this study. The study period was comprised between July 2008 and September 2013.

Results

DCS-score resulted in 17 satisfactory results, whereas Nonarthritic Hip Score (NAHS) resulted in mean improvement of 39 points. 1 retrieved allograft demonstrated 8 weeks after implantation new whole revascularisation.

Conclusions

We concluded that labral reconstruction with tendon allograft provides relief of painful symptoms, and represents a reliable alternative for patients with nonrepairable labral tears that are not yet candidates for a joint replacement procedure.
Extrarticular HIP Impingement
Authors: Marin-Peña Óliver , Sierra-Madrid Pablo , Lax-Pérez Raquel , Ferrero-Manzanal Francisco
Published: May 2016

Extrarticular causes of impingement have a current, interesting role in the complaint of groin pain in athletes. Subspine impingement is related to a prominent anterior inferior iliac spine (AIIS) and is actually described as a frequent cause of groin pain. Ischiofemoral impingement is described when the space between the lesser trochanter is decreased. Psoas impingement appears between the psoas tendon and the anterior labrum and anterior acetabular rim.
Involvement of Myeloperoxidase Gene Polymorphism 463G>A in Development of Cervical Squamous Cell Carcinoma
Authors: Roszak Andrzej , Lutkowska Anna , Lianeri Margarita , Sowińska Anna , Jagodziński Paweł P.
Published: May 2016

Background

The myeloperoxidase (MPO) -463G>A (rs2333227) polymorphism has been linked with increased susceptibility to the development of various malignancies. However, the data on the association of the MPO -463G>A transition with cervical cancer remain inconsistent.

Methods

Using high resolution melting analysis we genotyped this polymorphism in women with cervical squamous cell carcinoma (SCC) (n = 476) and controls (n = 493) from a Polish Caucasian population. Logistic regression analysis was used to adjust for the effect of confounders such as age, parity, oral contraceptive use, tobacco smoking, and menopausal status, and revealed that the MPO -463G>A single nucleotide polymorphism (SNP) was associated with an increased risk of SCC.

Results

The adjusted odds ratio (OR) for patients with the A/A genotype versus G/G genotype was 0.718 (95% CI 0.531-0.972, p = 0.0316). Stratified analyses between the MPO -463G>A polymorphism and SCC risks demonstrated a protective role of the MPO -463G>A SNP in patients with a positive history of parity and negative history of tobacco smoking. In patients with a positive history of parity, the age-adjusted OR for the A/A versus G/G genotype was 0.667 (95% CI 0.479-0.929, p = 0.0164). The age-adjusted OR for patients with a negative history of tobacco smoking for the A/A versus G/G genotype was 0.491 (95% CI 0.313-0.770, p = 0.0019).

Conclusions

Our study demonstrated that the MPO -463G>A SNP may protect from SCC in women from Polish Caucasian populations.
Técnica, metafísica e totalitarismo à luz da tragédia
Authors: Prado Tomás Mendonça da Silva
Published: May 2016

resumo: Este trabalho investiga os laços entre a técnica, a metafísica e o totalitarismo, com base nos pensamentos de Heidegger e Arendt. Além disso, propõe que tais análises sugerem que a filosofia e a história pertencem a um enredo trágico fundamental. Para tanto, de início pesquisamos em que medida o ambivalente sentido de esgotamento e salvação, presente em diversas abordagens da técnica, implica a produção de prognósticos e uma reflexão teleológica. Investigamos se estes são elementos que, no século XX, serviram de artifício para a legitimação da barbárie em movimentos totalitários e se permanecem necessariamente intrínsecos a toda visão da técnica. A abordagem de Heidegger, em alternativa, volta-se às origens da metafísica, onde residem as decisões que teriam culminado na técnica moderna, e onde presumimos estar enraizada esta estrutura trágica.abstract: This study investigates the links between art, metaphysics and totalitarianism, based on the thoughts of Heidegger and Arendt. It also proposes that such analyses suggest that philosophy and history belong to a fundamental tragic plot. To do so, we start researching how the ambivalent sense of exhaustion and salvation, present in many approaches of technique, involves the production of prognoses and teleological reflection. We investigate if these are elements which, in the twentieth century, served as a device for legitimizing barbarity in totalitarian movements and if it remains necessarily intrinsic to every view of technique. Heidegger's approach, instead, turns to the origins of metaphysics, where the decisions that would have culminated in modern technique lie, and where we presume this tragic structure is rooted.
A relação entre ciência e tecnologia a partir de três modelos teóricos distintos
Authors: Szczepanik Gilmar Evandro
Published: May 2016

resumo: Este artigo tem por objetivo explorar as possíveis relações estabelecidas entre ciência e a tecnologia a partir de três modelos teóricos distintos. O primeiro modelo teórico é chamado de hierárquico e pressupõe uma relação de subordinação entre ciência e a tecnologia. O segundo modelo é denominado de não hierárquico e sustenta que ciência e a tecnologia se encontram fundidas de tal modo que não faz mais sentido tentar entendê-las separadamente. Por fim, o terceiro modelo teórico designado de emancipatório explora alguns elementos que permitem compreender a ciência e a tecnologia ainda como atividades distintas, embora possam trabalhar conjuntamente algumas vezes.Abstract:  This paper aims to  understand the possible  relations between science and technology from three different theoretical models. The first theoretical model is called hierarchical and implies a subordinate relationship between science and technology. The second model  is  called non-hierarchical  and argues  that  science  and technology are fused so that it makes more sense to try to understand them separately. Finally, the third theoretical model is called emancipatory  and explores some elements that allow us to understand science and technology as separate activities, although they may sometimes work together.
O diálogo entre arte, filosofia, poesia e técnica na construção de uma “história do ser” no pensamento tardio de Martin Heidegger
Authors: Costa Dias Luciana
Published: May 2016

resumo: Pretende-se discutir a relação entre arte, filosofia, poesia e técnica na construção de uma “história do ser”, tal como esta progressivamente se constrói na obra de Martin Heidegger, sobretudo em seus escritos a partir de meados da década de 1930.abstract: The aim of this work is to discuss the relationship between art, philosophy, poetry and technique in the so-called “history of being”, as the latter is gradually built in the work of Martin Heidegger, particularly in his writings since the mid-1930s.
A RACIONALIDADE TECNOCIENTÍFICA E O SEU DESAFIO À FILOSOFIA DA CIÊNCIA
Authors: Cupani Alberto
Published: May 2016

resumo: A Filosofia da Ciência ocupa-se com a racionalidade da ciência, mas a ciência tradicional vai sendo crescentemente substituída pela tecnociência, que implica uma diferente racionalidade, ou seja, uma diferente maneira de justificar seus propósitos e métodos. Neste artigo descrevemos as origens e a evolução histórica da tecnociência e as mudanças que ela introduz na pesquisa científica, particularmente no seu ethos. Essas mudanças deveriam causar uma transformação na Filosofia da Ciência, fazendo com que inclua questões éticas e políticas junto com as epistemológicas, e que trabalhe em cooperação com outros estudos sobre a ciência.abstract: Philosophy of science deals with the rationality of science, but traditional science is increasingly replaced by technoscience, which implies a different rationality, that is, a different way of justifying its goals and methods. In this paper we describe the origins and historical evolution of technoscience, and the changes it introduces in scientific research, particularly in its ethos. Those changes should cause a transformation in the philosophy of science, making it to include ethical and political questions along with epistemological ones and to work in cooperation with other studies on science.
Natureza e artefato: laboratório como teatro de operações e manipulações materiais
Authors: Ramos Maurício , Mocelin Ronei Clécio
Published: May 2016

resumo: Neste artigo propomos abordar a relação entre os conceitos de natureza e de artefato a partir de uma racionalidade química e alquímica. Pretendemos mostrar que essa racionalidade é originariamente tecnocientífica e apontar o modo como alquimistas e químicos construíram um quadro conceitual ancorado no laboratório do químico e no laboratório do orgânico.  Nosso propósito é explicitar as transgressões e a capilaridade tecnocultural dos materiais criados nos laboratórios, bem como da existência de um estilo químico de raciocinar com suas particularidades ontológicas, epistemológicas e metodológicas.abstract: In this article we propose to treat the relation between the concepts of nature and  artifact from a chemical and alchemical rationality. We intend to show that this rationality  is  originally  technoscientific  and  to  point  out  the  way  alchemists  and chemists built a conceptual board anchored in the laboratory of the chemical and in the laboratory  of  the  organic.  Our  proposal  is  to  explain  the  transgressions  and technocultural  capillarity  of  the  materials  created in  the  laboratories,  as well  as  the  existence of  a  chemical  style  of  reasoning with its  ontological,  epistemological  and methodological particularities.
Mais que um, menos que muitos: a individuação e o programa filosófico de Simondon no “L'Individuation à la Lumière des Notions de Forme et d'Information ”.
Authors: Vieira Neto Paulo
Published: May 2016

resumo: Há uma solidariedade entre o estilo do L'Individuation à la Lumière des Notions de Forme et d'Information e os princípios teóricos que a obra toma como ponto de partida para sua investigação dos diversos processos de individuação. Essa solidariedade torna o estilo da obra um programa filosófico que responde a demandas precisas quanto ao papel das ciências da natureza, das ciências humanas e da técnica, sua classificação, sua história e sua consistência teórica, demandas que pretendemos especificar no artigo. Ao mesmo tempo esse programa de Simondon requer que o autor recolha os princípios teóricos de sua análise em um corpo teórico cujas linhas gerais desenham a fisonomia de toda uma filosofia, de caráter peculiar. É isso o que justifica, e até mesmo exige, que Simondon tome por objeto o problema da individuação nos termos em que o faz, e que possa apresentar essa aproximação do problema como uma crítica cujo valor é ele mesmo filosófico: uma resposta peculiar ao positivismo, ao pragmatismo, ao estruturalismo e, sobretudo, às formas de compreensão das ciências e das técnicas que era hegemônica no final dos anos 50, no ambiente intelectual francês.abstract: There is a strict allegiance between the style present in L'Individuation à la Lumière des Notions de Forme et d'Information and the theoretical principles by which this work inquires the diverse individuation processes. That allegiance makes this style a whole investigation program on the role of natural sciences, humanities and technology in general, their classification, history and theoretical nature. The clauses of that investigation will be shown in its general lines by the paper itself. But the point is that, at the same time, this investigation program requires the specific theoretical principles adopted by Simondon in this work as a theory and in its development as a complete philosophy. Indeed this is the reason why Simondon takes the problem about individuation processes as the focus of his discussions. Such discussions offer a critique whose value is itself philosophical. That strategy results in a peculiar response to positivism, pragmatism, structuralism and the hegemonic way of thinking about sciences and techniques in the French fifties.
A reflexão sobre a natureza e o problema da aplicação: entre realismo racional e filosofia transcendental (1799-1801)
Authors: Ferraguto Federico
Published: May 2016

O artigo trata da relação entre pensamento transcendental, aplicação e natureza nas reflexões de G. Bardili, K. L. Reinhold e J. G. Fichte, entre 1799 e 1801. Após uma primeira discussão das críticas à filosofia transcendental formuladas por Reinhold e Bardili (§ 2), são analisados os pressupostos da filosofia da natureza apresentada no Grundriss bardiliano (§ 3) e avaliada a expansão que aí opera a fenomenologia concebida por Reinhold (§ 4) no IV tomo dos Beyträge zur leichtern Übersicht des Zustandes der Philosophie beym Anfänge des 19. Jahrhunderts. Por fim (§ 5), se discute a posição que Fichte assume com respeito a estas tentativas nos apontamentos preparatórios à revisão do Grundriss bardiliano e nas Teses explicativas da essência dos animais (1800-1801), comparando-as aos desenvolvimentos sucessivos da sua reflexão sobre a natureza.
Fichte e Schelling em confronto – filosofia da reflexão ou não?
Authors: Gaspar Francisco Prata
Published: May 2016

O objetivo do artigo é apresentar a discussão entre Fichte e Schelling em torno do conflito entre o idealismo transcendental da doutrina-da-ciência e a filosofia-da-natureza do Identitätssystem (sistema-da-identidade). Buscamos compreender, de um ponto de vista fichteano, se e em que medida é possível afirmar que a doutrina-da-ciência é uma filosofia da reflexão, tal como entendida por Schelling. Para tanto, em um primeiro momento, serão expostas as críticas de Schelling a Fichte, como ele progressivamente se afasta em relação à filosofia transcendental e busca consolidar a filosofia-da-natureza. Em um segundo momento, daremos a palavra a Fichte e a seus apontamentos críticos em relação ao projeto filosófico de uma filosofia-da-natureza. Nossa análise limitar-se-á à correspondência entre os dois filósofos e aos textos escritos em torno do período de ruptura entre eles. No caso de Fichte, indo até 1804.The aim of this paper is to present the discussion between Fichte and Schelling around the conflict between the transcendental idealism of the doctrine of science and the philosophy of nature of the Identitätssystem. We seek to understand, under a Fichtean point of view, if and how far it is possible to state that the doctrine of science consists in a philosophy of reflection, such as Schelling states. For this, at first, will be exposed the Schelling’s critiques to Fichte, as the former progressively detaches himself from transcendental philosophy and consolidates a philosophy of nature. In a second moment, we will give the floor to Fichte’s critical notes related to the philosophical project of a philosophy of nature. Our analysis will be restraint to the correspondence between those two philosophers and to the texts written around this period of rupture between them. In the case of Fichte, this goes until 1804.
Merleau-Ponty e o marxismo: política e filosofia da história
Authors: Neves José Luiz B.
Published: May 2016

O diagnóstico de uma crise do marxismo, feito nos últimos textos publicados em vida por Merleau-Ponty, merece ser situado no interior da trajetória do próprio filósofo, cujos textos de juventude se aproximavam de Marx para pensar a filosofia da história. Procuro, nesse sentido, remontar aos textos dos anos 40 para observar como ali, a partir de uma certa leitura da práxis como articulação entre necessidade e contingência na história e da teoria do proletariado como encarnação dessa práxis, surgem algumas das dificuldades que levarão Merleau-Ponty, já no começo dos anos 50, a esboçar os contornos de uma nova filosofia da história.
Using Games as a Tool in Teaching Vocabulary to Young Learners
Authors: Bakhsh Sahar Ameer
Published: May 2016

Over the last few decades, teaching English become a phenomenon in Saudi Arabia, especially to young learners. English is taught as a main subject in kindergarten and elementary schools. Like any other children, Saudis accept new foreign languages easily, but they get bored very fast if the teacher is teaching them using the old conventional methods and techniques. The aim of this paper is to prove that games are effective tools when devised to explain vocabularies and they make it easier to remember their meanings. This paper deals with a literature review of teaching English vocabulary to young learners using games. Then it discusses the importance of using games in teaching vocabulary and in what way using them is helpful. After that it investigates the practical implications of using games to teach vocabulary that includes the implementation of vocabulary games and some examples of games that could be used to teach vocabulary to children. And finally it examines challenges teachers face when teaching vocabulary using games to young learners.
„Díky, Ameriko!“: dramaturgická analýza Slavností svobody v „nejameričtějším“ městě Evropy
Authors: Krčál Petr , Naxera Vladimír
Published: May 2016

The following article aims to provide an interpretation of the annual public occasion called the “Liberation Festival” in Pilsen. The Liberation Festival serves as a celebration of the liberation of Pilsen by the U.S. army. Our paper presents a dramaturgical analysis of this occasion. More specifically, our effort is focused on two main interpretative threads. With respect to the first one (called “the production of discourse”) we analyse the processes of the (re)production of political discourse related to this public occasion. We also identify the main discourse that is typically produced or reinforced during the Liberation Festival. The second interpretative thread is called “the organizational line of the Liberation Festival”. Here, we try to provide examples and identify characteristics of the strategies and practices that can be employed by state apparatuses to present themselves as guarantors of the security of festival goers. Our findings confirm that public ceremonies (like the Liberation Festival) can fulfil the role of a medium that serves to spread actual political discourse, the veneration of actual societal normative order, and a positive portrait of state apparatuses. Our article can thus be viewed as a contribution to the debate on the reproduction of political discourse through public spectacles.
Jean-Paul Gagnon: Democratic Theorists in Conversation: Turns in Contemporary Thought
Authors: Jaroš Bronislav
Published: May 2016

Knižní recenze / Book review.
Best creek-jumping methods
Authors: Polly Drew
Published: May 2016

Each month this section of the Problem Solvers department discusses the classroom results of using problems presented in previous issues of Teaching Children Mathematics. The problem from last year offers a powerful opportunity to involve preservice teachers and elementary school students in an exploration with authentic content.
Reading Students' Representations
Authors: Diezmann Carmel M. , McCosker Natalie T.
Published: May 2016

Students' text, symbols, and graphics give teachers a glimpse into mathematical thinking associated with investigating the Peas problem.
A feedback amplification loop between stem cells and their progeny promotes tissue regeneration and tumorigenesis
Authors: Chen Jun , Xu Na , Huang Huanwei , Cai Tao , Xi Rongwen
Published: May 2016

Homeostatic renewal of many adult tissues requires balanced self-renewal and differentiation of local stem cells, but the underlying mechanisms are poorly understood. Here we identified a novel feedback mechanism in controlling intestinal regeneration and tumorigenesis in Drosophila. Sox21a, a group B Sox protein, is preferentially expressed in the committed progenitor named enteroblast (EB) to promote enterocyte differentiation. In Sox21a mutants, EBs do not divide, but cannot differentiate properly and have increased expression of mitogens, which then act as paracrine signals to promote intestinal stem cell (ISC) proliferation. This leads to a feedback amplification loop for rapid production of differentiation-defective EBs and tumorigenesis. Notably, in normal intestine following damage, Sox21a is temporally downregulated in EBs to allow the activation of the ISC-EB amplification loop for epithelial repair. We propose that executing a feedback amplification loop between stem cells and their progeny could be a common mechanism underlying tissue regeneration and tumorigenesis.
Compensation for PKMζ in long-term potentiation and spatial long-term memory in mutant mice
Authors: Tsokas Panayiotis , Hsieh Changchi , Yao Yudong , Lesburguères Edith , Wallace Emma Jane Claire , Tcherepanov Andrew , Jothianandan Desingarao , Hartley Benjamin Rush , Pan Ling , Rivard Bruno , Farese Robert V , Sajan Mini P , Bergold Peter John , Hernández Alejandro Iván , Cottrell James E , Shouval Harel Z , Fenton André Antonio , Sacktor Todd Charlton
Published: May 2016

PKMζ is a persistently active PKC isoform proposed to maintain late-LTP and long-term memory. But late-LTP and memory are maintained without PKMζ in PKMζ-null mice. Two hypotheses can account for these findings. First, PKMζ is unimportant for LTP or memory. Second, PKMζ is essential for late-LTP and long-term memory in wild-type mice, and PKMζ-null mice recruit compensatory mechanisms. We find that whereas PKMζ persistently increases in LTP maintenance in wild-type mice, PKCι/λ, a gene-product closely related to PKMζ, persistently increases in LTP maintenance in PKMζ-null mice. Using a pharmacogenetic approach, we find PKMζ-antisense in hippocampus blocks late-LTP and spatial long-term memory in wild-type mice, but not in PKMζ-null mice without the target mRNA. Conversely, a PKCι/λ-antagonist disrupts late-LTP and spatial memory in PKMζ-null mice but not in wild-type mice. Thus, whereas PKMζ is essential for wild-type LTP and long-term memory, persistent PKCι/λ activation compensates for PKMζ loss in PKMζ-null mice.
Microsatellite loci discovery from next-generation sequencing data and loci characterization in the epizoic barnacleChelonibia testudinaria(Linnaeus, 1758)
Authors: Ewers-Saucedo Christine , Zardus John D. , Wares John P.
Published: May 2016

Microsatellite markers remain an important tool for ecological and evolutionary research, but are unavailable for many non-model organisms. One such organism with rare ecological and evolutionary features is the epizoic barnacleChelonibia testudinaria(Linnaeus, 1758).Chelonibia testudinariaappears to be a host generalist, and has an unusual sexual system, androdioecy. Genetic studies on host specificity and mating behavior are impeded by the lack of fine-scale, highly variable markers, such as microsatellite markers. In the present study, we discovered thousands of new microsatellite loci from next-generation sequencing data, and characterized 12 loci thoroughly. We conclude that 11 of these loci will be useful markers in future ecological and evolutionary studies onC. testudinaria.
Investigating body patterning in aquarium-raised flamboyant cuttlefish (Metasepia pfefferi)
Authors: Thomas Amber , MacDonald Christy
Published: May 2016

Cuttlefish are known for their ability to quickly alter their total appearance, or body pattern, to camouflage or to communicate with predators, prey and conspecifics. The body patterns of some species have been extensively documented to gain a better understanding of their behaviors. However, the flamboyant cuttlefish (Metasepia pfefferi) is largely unstudied. Recently, aquarists have been able to breed, house and displayM. pfefferi, giving researchers ample opportunities to study their behavior under those conditions. This study aimed to identify the dorsally-visible components of the body patterns used by 5 sexually-mature, freely-behaving, F5 generationM. pfefferiin their home aquarium at The Seas in Epcot at Walt Disney World Resorts®, Lake Buena Vista, FL, USA. Furthermore, we aimed to determine the most probable patterns used by this population of animals and to create a database of components that can be used in future behavioral studies. We found that this population ofM. pfefferiuse a combination of 7 textural, 14 postural, 7 locomotor and between 42 and 75 chromatic components in their home aquarium. Using maximum likelihood analysis and AutoClass@IJM software, we found that these components combine to generate 11 distinct body patterns. The software was able to sort 98% of the live animal observations into one of the 11 patterns with 90% confidence and 88% of observations with 99% confidence. Unusually for cuttlefish, 8 of the 11 identified patterns contained at least one “traveling” component (i.e., traveling waves or blinking spots) in which the colors on the skin appeared to travel on the animal’s mantle. In other species, these components are generally seen during hunting or aggression, but this population ofM. pfefferiuses them frequently during a variety of contexts in their home aquarium. With few published data on the behavior ofM. pfefferiin their natural environment, we cannot compare the behavior of the tank-raised individuals in this study to animals in the wild. However, this study provides the groundwork necessary for future studies ofM. pfefferibody patterning and behavior.
WACCM‐D—Whole Atmosphere Community Climate Model with D‐region ion chemistry
Authors: Verronen P. T. , Andersson M. E. , Marsh D. R. , Kovács T. , Plane J. M. C.
Published: May 2016

Energetic particle precipitation (EPP) and ion chemistry affect the neutral composition of the polar middle atmosphere. For example, production of odd nitrogen and odd hydrogen during strong events can decrease ozone by tens of percent. However, the standard ion chemistry parameterization used in atmospheric models neglects the effects on some important species, such as nitric acid. We present WACCM‐D, a variant of the Whole Atmosphere Community Climate Model, which includes a set of lower ionosphere (D‐region) chemistry: 307 reactions of 20 positive ions and 21 negative ions. We consider realistic ionization scenarios and compare the WACCM‐D results to those from the Sodankylä Ion and Neutral Chemistry (SIC), a state‐of‐the‐art 1‐D model of the D‐region chemistry. We show that WACCM‐D produces well the main characteristics of the D‐region ionosphere, as well as the overall proportion of important ion groups, in agreement with SIC. Comparison of ion concentrations shows that the WACCM‐D bias is typically within ±10% or less below 70 km. At 70–90 km, when strong altitude gradients in ionization rates and/or ion concentrations exist, the bias can be larger for some groups but is still within tens of percent. Based on the good agreement overall and the fact that part of the differences are caused by different model setups, WACCM‐D provides a state‐of‐the‐art global representation of D‐region ion chemistry and is therefore expected to improve EPP modeling considerably. These improvements are demonstrated in a companion paper by Andersson et al.
Imprecise probabilistic estimation of design floods with epistemic uncertainties
Authors: Qi Wei , Zhang Chi , Fu Guangtao , Zhou Huicheng
Published: May 2016

An imprecise probabilistic framework for design flood estimation is proposed on the basis of the Dempster‐Shafer theory to handle different epistemic uncertainties from data, probability distribution functions, and probability distribution parameters. These uncertainties are incorporated in cost‐benefit analysis to generate the lower and upper bounds of the total cost for flood control, thus presenting improved information for decision making on design floods. Within the total cost bounds, a new robustness criterion is proposed to select a design flood that can tolerate higher levels of uncertainty. A variance decomposition approach is used to quantify individual and interactive impacts of the uncertainty sources on total cost. Results from three case studies, with 127, 104, and 54 year flood data sets, respectively, show that the imprecise probabilistic approach effectively combines aleatory and epistemic uncertainties from the various sources and provides upper and lower bounds of the total cost. Between the total cost and the robustness of design floods, a clear trade‐off which is beyond the information that can be provided by the conventional minimum cost criterion is identified. The interactions among data, distributions, and parameters have a much higher contribution than parameters to the estimate of the total cost. It is found that the contributions of the various uncertainty sources and their interactions vary with different flood magnitude, but remain roughly the same with different return periods. This study demonstrates that the proposed methodology can effectively incorporate epistemic uncertainties in cost‐benefit analysis of design floods.
Sensitivity of emergent sociohydrologic dynamics to internal system properties and external sociopolitical factors: Implications for water management
Authors: Elshafei Y. , Tonts M. , Sivapalan M. , Hipsey M. R.
Published: May 2016

It is increasingly acknowledged that effective management of water resources requires a holistic understanding of the coevolving dynamics inherent in the coupled human‐hydrology system. One of the fundamental information gaps concerns the sensitivity of coupled system feedbacks to various endogenous system properties and exogenous societal contexts. This paper takes a previously calibrated sociohydrology model and applies an idealized implementation, in order to: (i) explore the sensitivity of emergent dynamics resulting from bidirectional feedbacks to assumptions regarding (a) internal system properties that control the internal dynamics of the coupled system and (b) the external sociopolitical context; and (ii) interpret the results within the context of water resource management decision making. The analysis investigates feedback behavior in three ways, (a) via a global sensitivity analysis on key parameters and assessment of relevant model outputs, (b) through a comparative analysis based on hypothetical placement of the catchment along various points on the international sociopolitical gradient, and (c) by assessing the effects of various direct management intervention scenarios. Results indicate the presence of optimum windows that might offer the greatest positive impact per unit of management effort. Results further advocate management tools that encourage an adaptive learning, community‐based approach with respect to water management, which are found to enhance centralized policy measures. This paper demonstrates that it is possible to use a place‐based sociohydrology model to make abstractions as to the dynamics of bidirectional feedback behavior, and provide insights as to the efficacy of water management tools under different circumstances.
Methane emission through ebullition from an estuarine mudflat: 1. A conceptual model to explain tidal forcing based on effective stress changes
Authors: Chen Xi , Slater Lee
Published: May 2016

Ebullition is an important pathway for transport of methane (CH4) to the atmosphere in wetlands. Water level changes have been suggested to trigger ebullition, especially in tidally flooded areas, although the controlling mechanisms remain uncertain. Bubble transport in submerged sediment represents a multiphase, dynamic interaction between gaseous and solid phases under the modulation of a liquid phase. An unvegetated sediment monolith was retrieved from an estuarine mudflat area at a tidal marsh site and maintained in a saturated state. Laboratory measurements on the mud monolith confirmed that not only ebbing tides, but also flooding tides could trigger ebullition releases of gas bubbles. We develop a Changing Stress for Simulating Ebullition (CSSE) model to describe mechanisms controlling bubble expansion in response to water level changes to unify these observations. Decreases in water level are assumed to lower the effective stress surrounding isolated trapped gas bubbles, driving upward transport via bubble expansion and deformation, with associated fracturing of overlying sediments. Increases in relative permittivity suggest that additional water invades macropores, with associated pore expansion, during the initial stage of increases in water level. We propose that subsequent matrix expansion under lowered effective stress on rising tides also leads to fracture propagation and bubble release. Our findings demonstrate the importance of effective stress changes in triggering ebullition from mudflat areas in tidal wetlands, modulated by the mechanical properties of shallow soft sediments.
Flash flooding in small urban watersheds: Storm event hydrologic response
Authors: Yang Long , Smith James A. , Baeck Mary Lynn , Zhang Yan
Published: May 2016

We analyze flash flooding in small urban watersheds, with special focus on the roles of rainfall variability, antecedent soil moisture, and urban storm water management infrastructure in storm event hydrologic response. Our results are based on empirical analyses of high‐resolution rainfall and discharge observations over Harry's Brook watershed in Princeton, New Jersey, during 2005–2006, as well as numerical experiments with the Gridded Surface Subsurface Hydrologic Analysis (GSSHA) model. We focus on two subwatersheds of Harry's Brook, a 1.1 km2 subwatershed which was developed prior to modern storm water management regulations, and a 0.5 km2 subwatershed with an extensive network of storm water detention ponds. The watershed developed prior to modern storm water regulations is an “end‐member” in urban flood response, exhibiting a frequency of flood peaks (with unit discharge exceeding 1 m3 s−1 km−2) that is comparable to the “flashiest” watersheds in the conterminous U.S. Observational analyses show that variability in storm event water balance is strongly linked to peak rain rates at time intervals of less than 30 min and only weakly linked to antecedent soil moisture conditions. Peak discharge for both the 1.1 and 0.5 km2 subwatersheds are strongly correlated with rainfall rate averaged over 1–30 min. Hydrologic modeling analyses indicate that the sensitivity of storm event hydrologic response to spatial rainfall variability decreases with storm intensity. Temporal rainfall variability is relatively more important than spatial rainfall variability in representing urban flood response, especially for extreme storm events.
Variability in isotopic composition of base flow in two headwater streams of the southern Appalachians
Authors: Singh Nitin K. , Emanuel Ryan E. , McGlynn Brian L.
Published: May 2016

We investigated the influence of hillslope scale topographic characteristics and the relative position of hillslopes along streams (i.e., internal catchment structure) on the isotopic composition of base flow in first‐order, forested headwater streams at Coweeta Hydrologic Laboratory. The study focused on two adjacent forested catchments with different topographic characteristics. We used stable isotopes (18O and 2H) of water together with stream gauging and geospatial analysis to evaluate relationships between internal catchment structure and the spatiotemporal variability of base flow δ18O. Base flow δ18O was variable in space and time along streams, and the temporal variability of base flow δ18O declined with increasing drainage area. Base flow became enriched in 18O moving along streams from channel heads to catchment outlets but the frequency of enrichment varied between catchments. The spatiotemporal variability in base flow δ18O was high adjacent to large hillslopes with short flow paths, and it was positively correlated with the relative arrangement of hillslopes within the catchment. These results point to influence of unique arrangement of hillslopes on the patterns of downstream enrichment. Spatial variability in base flow δ18O within the streams was relatively low during dry and wet conditions, but it was higher during the transition period between dry and wet conditions. These results suggest that the strength of topographic control on the isotopic composition of base flow can vary with catchment wetness. This study highlights that topographic control on base flow generation and isotopic composition is important even at fine spatial scales.
Geophysical controls of chemical disequilibria in Europa
Authors: Vance S. D. , Hand K. P. , Pappalardo R. T.
Published: May 2016

The ocean in Jupiter's moon Europa may have redox balance similar to Earth's. On Earth, low‐temperature hydration of crustal olivine produces substantial hydrogen, comparable to any potential flux from volcanic activity. Here we compare hydrogen and oxygen production rates of the Earth system with fluxes to Europa's ocean. Even without volcanic hydrothermal activity, water‐rock alteration in Europa causes hydrogen fluxes 10 times smaller than Earth's. Europa's ocean may have become reducing for a brief epoch, for example, after a thermal‐orbital resonance ∼2 Gyr after accretion. Estimated oxidant flux to Europa's ocean is comparable to estimated hydrogen fluxes. Europa's ice delivers oxidants to its ocean at the upper end of these estimates if its ice is geologically active, as evidence of geologic activity and subduction implies.