bluuebunny/crossref_metadata_2025 huggingface dataset:
FINE SLICING OF THE VALUE CHAIN AND OFFSHORING OF ESSENTIAL ACTIVITIES: EMPIRICAL EVIDENCE FROM EUROPEAN MULTINATIONALS
Authors: Linares-Navarro Esmeralda , Pedersen Torben , Pla-Barber José
Published: March 2014

The offshoring of more advanced activities is increasing and a debate about the limits of offshoring has emerged. Companies are fine-slicing their value chains, and moving beyond the offshoring of peripheral and non-core activities to the offshoring of advanced and essential activities that are closer to their core (e.g. research, design and product development). The challenge is to understand the limits of offshoring and the most appropriate modes of offshoring. The purpose of this paper is to analyze what activities are offshorable and how best to govern offshored activities. We argue that companies are redefining their core activities and in this process, some essential activities previously viewed as core activities are being detached from the core, and they become more offshorable.
EXPLORING MODES OF ENTRY INTO INTERNATIONAL MARKETS: DIRECT INVESTMENT OR CONTRACTUAL RELATIONS
Authors: Fernandes Rui , Gouveia Borges , Pinho Carlos
Published: March 2014

We consider the multinational company's decision on whether to enter a new foreign market using direct investment by establishing a subsidiary, direct exporting or contracting a local distributor, with the option to invest later. We develop two models, based on the real options theory, to support such decisions. The option on direct exporting or on a local distributor allows the firm to minimize risks by finding out if the market is large enough to support future direct investment. We find the direct investment to be the desirable mode of entry in large markets subject to low demand uncertainty. Overall, the investigation increases the knowledge related with exploring new markets subject to demand uncertainty, valuing the flexibility of present and future options.
The Metaphor-Simulation Paradox in the Study of Computer Games
Authors: Möring Sebastian
Published: March 2014

This article discusses the metaphor-simulation paradox in the study of computer games. It is derived from three observations. Firstly, often when authors use the concept of metaphor with regard to games they use it in conceptual and textual vicinity to the concept of simulation. Secondly, the concept of metaphor is often applied to signify seemingly abstract games in opposition to mimetic simulations. Both observations can be made within an artgame discourse of the study of computer games as well as within the more general discourse of the study of computer games. Thirdly, however, the definitions for simulation as well as for metaphor are strikingly similar which culminates in the metaphor-simulation paradox i.e. the notions of metaphor and simulation are not distinct enough in order to make the distinctions which are usually made with these notions with regard to computer games. In an attempt to reconcile both notions with regard to computer games this article will make three suggestions. Observing that simulations are often called metaphors with regard to their degree of reduction or abstraction the first suggestion argues that simulations are essentially synecdochic and hence metaphoric when following a broad notion of metaphor. Based on the assumption that simulation is not a matter of similarity the second suggestion proposes to distinguish between a first order simulation and a second order simulation which can then be considered metaphoric. As a third and final suggestion the author offers to consider simulation and metaphor as related via the notion of the model. Simulations are based on models and metaphors provide models such that one can speak of metaphor based simulations.
Central Role of Conventional Dendritic Cells in Regulation of Bone Marrow Release and Survival of Neutrophils
Authors: Jiao Jingjing , Dragomir Ana-Cristina , Kocabayoglu Peri , Rahman Adeeb H. , Chow Andrew , Hashimoto Daigo , Leboeuf Marylene , Kraus Thomas , Moran Thomas , Carrasco-Avino Gonzalo , Friedman Scott L. , Merad Miriam , Aloman Costica
Published: March 2014

Neutrophils are the most abundant cell type in the immune system and play an important role in the innate immune response. Using a diverse range of mouse models with either defective dendritic cell (DC) development or conditional DC depletion, we provide in vivo evidence indicating that conventional DCs play an important role in the regulation of neutrophil homeostasis. Flk2, Flt3L, and Batf3 knockout mice, which have defects in DC development, have increased numbers of liver neutrophils in the steady state. Conversely, neutrophil frequency is reduced in DC-specific PTEN knockout mice, which have an expansion of CD8+ and CD103+ DCs. In chimeric CD11c-DTR mice, conventional DC depletion results in a systemic increase of neutrophils in peripheral organs in the absence of histological inflammation or an increase in proinflammatory cytokines. This effect is also present in splenectomized chimeric CD11c-DTR mice and is absent in chimeric mice with 50% normal bone marrow. In chimeric CD11c-DTR mice, diphtheria toxin treatment results in enhanced neutrophil trafficking from the bone marrow into circulation and increased neutrophil recruitment. Moreover, there is an increased expression of chemokines/cytokines involved in neutrophil homeostasis and reduced neutrophil apoptosis. These data underscore the role of the DC pool in regulating the neutrophil compartment in nonlymphoid organs.
The Epidermal Growth Factor Receptor Is a Regulator of Epidermal Complement Component Expression and Complement Activation
Authors: Abu-Humaidan Anas H. A. , Ananthoju Nageshwar , Mohanty Tirthankar , Sonesson Andreas , Alberius Per , Schmidtchen Artur , Garred Peter , Sørensen Ole E.
Published: March 2014

The complement system is activated in response to tissue injury. During wound healing, complement activation seems beneficial in acute wounds but may be detrimental in chronic wounds. We found that the epidermal expression of many complement components was only increased to a minor extent in skin wounds in vivo and in cultured keratinocytes after exposure to supernatant from stimulated mononuclear cells. In contrast, the epidermal expression of complement components was downregulated in ex vivo injured skin lacking the stimulation from infiltrating inflammatory cells but with intact injury-induced epidermal growth factor receptor (EGFR)–mediated growth factor response. In cultured primary keratinocytes, stimulation with the potent EGFR ligand, TGF-α, yielded a significant downregulation of complement component expression. Indeed, EGFR inhibition significantly enhanced the induction of complement components in keratinocytes and epidermis following stimulation with proinflammatory cytokines. Importantly, EGFR inhibition of cultured keratinocytes either alone or in combination with proinflammatory stimulus promoted activation of the complement system after incubation with serum. In keratinocytes treated solely with the EGFR inhibitor, complement activation was dependent on serum-derived C1q, whereas in keratinocytes stimulated with a combination of proinflammatory cytokines and EGFR inhibition, complement activation was found even with C1q-depleted serum. In contrast to human keratinocytes, EGFR inhibition did not enhance complement component expression or cause complement activation in murine keratinocytes. These data demonstrate an important role for EGFR in regulating the expression of complement components and complement activation in human epidermis and keratinocytes and, to our knowledge, identify for the first time a pathway important for the epidermal regulation of complement activation.
Cutting Edge: Committed Th1 CD4+ T Cell Differentiation Blocks Pregnancy-Induced Foxp3 Expression with Antigen-Specific Fetal Loss
Authors: Xin Lijun , Ertelt James M. , Rowe Jared H. , Jiang Tony T. , Kinder Jeremy M. , Chaturvedi Vandana , Elahi Shokrollah , Way Sing Sing
Published: March 2014

Pregnancy stimulates induced Foxp3 expression among maternal CD4+ T cells with fetal specificity. Although sustained maternal regulatory CD4+ T cell (Treg) expansion is essential for maintaining fetal tolerance during pregnancy, the necessity for Foxp3+ cells with fetal specificity remains undefined. In this study, we demonstrate that mitigating Treg differentiation among maternal CD4+ T cells with a single surrogate fetal specificity elicits Ag-specific fetal loss. Using recombinant Listeria monocytogenes to prime stably differentiated Th1 CD4+ T cells with fetal I-Ab:2W1S55–68 specificity refractory to pregnancy-induced Foxp3 expression, we show that Ag delivery by cytoplasmic L. monocytogenes causes selective loss of 2W1S+ offspring through CD4 cell– and IFN-γ–dependent pathways. In contrast, CD4+ T cells primed by L. monocytogenes restricted from the cell cytoplasm are markedly more plastic for induced Foxp3 expression, with normal pregnancy outcomes. Thus, committed Th1 polarization blocks pregnancy induced Treg differentiation among maternal CD4+ T cells with fetal specificity and triggers Ag-specific fetal loss.
The DNA of prophetic speech
Authors: De Wet Friedrich W.
Published: March 2014

Having to speak words that can potentially abuse the divine connotation of prophetic speech for giving authority to the own manipulative intent poses a daunting challenge to preachers. The metaphorical images triggered by ‘DNA’ and ‘genetic engineering’ are deployed in illustrating the ambivalent position in which a prophetic preacher finds himself or herself; ambivalence between anticipation of regeneration at the deepest level of humanity on the one hand, and disquiet about the possibility of forcing a human being against his or her will into meeting certain prescribed expectations on the other hand. In reflecting on possible responses to this ambivalence, the theological positions of two prolific scholars in the research field of Homiletics, Gijs D.J. Dingemans and Charles L. Campbell, are critically considered from the point of view of the relationship between Christology and Pneumatology. In reflecting on theological markers for a sensible response, the author argues for a pneumatology in which the work of the Spirit consists of grafting the very DNA of our humanity and all its faculties into Christ, the only One who can open up the true life that is intended for humanity by divine grace. It will be in the very genes of a prophet to speak graceful words, because the prophet will have seen the wonder of the working of divine grace in his or her own life and will have embraced it willingly and joyfully.
Meteorological Variables and Bacillary Dysentery Cases in Changsha City, China
Authors: Gao Lu , Zhang Ying , Ding Guoyong , Liu Qiyong , Zhou Maigeng , Li Xiujun , Jiang Baofa
Published: March 2014

This study aimed to investigate the association between meteorological-related risk factors and bacillary dysentery in a subtropical inland Chinese area: Changsha City. The cross-correlation analysis and the Autoregressive Integrated Moving Average with Exogenous Variables (ARIMAX) model were used to quantify the relationship between meteorological factors and the incidence of bacillary dysentery. Monthly mean temperature, mean relative humidity, mean air pressure, mean maximum temperature, and mean minimum temperature were significantly correlated with the number of bacillary dysentery cases with a 1-month lagged effect. The ARIMAX models suggested that a 1°C rise in mean temperature, mean maximum temperature, and mean minimum temperature might lead to 14.8%, 12.9%, and 15.5% increases in the incidence of bacillary dysentery disease, respectively. Temperature could be used as a forecast factor for the increase of bacillary dysentery in Changsha. More public health actions should be taken to prevent the increase of bacillary dysentery disease with consideration of local climate conditions, especially temperature.
A semi-Lagrangian view of ozone production tendency in North American outflow in the summers of 2009 and 2010
Authors: Zhang B. , Owen R. C. , Perlinger J. A. , Kumar A. , Wu S. , Val Martin M. , Kramer L. , Helmig D. , Honrath R. E.
Published: March 2014

Abstract. The Pico Mountain Observatory, located at 2225 m a.s.l. in the Azores Islands, was established in 2001 to observe long-range transport from North America to the central North Atlantic. In previous research conducted at the observatory, ozone enhancement (> 55 ppbv) in North American outflows was observed, and efficient ozone production in these outflows was postulated. This study is focused on determining the causes for high d[O3] / d[CO] values (~1 ppbv ppbv−1) observed in the summers of 2009 and 2010. The folded retroplume technique, developed by Owen and Honrath (2009), was applied to combine upwind FLEXPART transport pathways with GEOS-Chem chemical fields. The folded result provides a semi-Lagrangian view of polluted North American outflow in terms of physical properties and chemical processes, including production/loss rate of ozone and NOx produced by lightning and thermal decomposition of peroxy acetyl nitrate (PAN). Two transport events from North America were identified for detailed analysis. High d[O3] / d[CO] was observed in both events, but due to differing transport mechanisms, ozone production tendency differed between the two. A layer of net ozone production was found at 2 km a.s.l. over the Azores in the first event plume, apparently driven by PAN decomposition during subsidence of air mass in the Azores–Bermuda High. In the second event, net ozone loss occurred during transport in the lower free troposphere, yet observed d[O3] / d[CO] was high. We estimate that in both events, CO loss through oxidation contributed significantly to d[O3] / d[CO] enhancement. Thus, it is not appropriate to use CO as a passive tracer of pollution in these events. In general, use of d[O3] / d[CO] as an indicator of net ozone production/loss may be invalid for any situation in which oxidants are elevated. Based on our analysis, use of d[O3] / d[CO] to diagnose ozone enhancement without verifying the assumption of negligible CO loss is not advisable.
A parameterisation for the activation of cloud drops including the effects of semi-volatile organics
Authors: Connolly P. J. , Topping D. O. , Malavelle F. , McFiggans G.
Published: March 2014

Abstract. We present a parameterisation of aerosol activation, including co-condensation of semi-volatile organics, for warm clouds that has applications in large-scale numerical models. The scheme is based on previously developed parameterisations that are in the literature, but has two main modifications. The first is that the total aerosol mass is modified by the condensation of organic vapours entering cloud base, whereas the second is that this addition of mass acts to modify the median diameter and the geometric standard deviation of the aerosol size distribution. It is found that the scheme is consistent with parcel model calculations of co-condensation under different regimes. Such a parameterisation may find use in evaluating important feedbacks in climate models.
Modeling ultrafine particle growth at a pine forest site influenced by anthropogenic pollution during BEACHON-RoMBAS 2011
Authors: Cui Y. Y. , Hodzic A. , Smith J. N. , Ortega J. , Brioude J. , Matsui H. , Turnipseed A. , Winkler P. , de Foy B.
Published: March 2014

Abstract. Formation and growth of ultrafine particles is crudely represented in chemistry-climate models, which contributes to uncertainties in aerosol composition, size distribution, and aerosol effects on cloud condensation nuclei (CCN) concentrations. Measurements of ultrafine particles, their precursor gases, and meteorological parameters were performed in a ponderosa pine forest in the Colorado Front Range in July–August 2011, and were analyzed to study processes leading to Aitken-mode Particle burst Events (APEs). These measurements suggest that APEs were associated with the arrival at the site of anthropogenic pollution plumes around noon or in the early afternoon. Number concentrations of ultrafine (4 to 30 nm diameter) particles typically exceeded 10 000 cm−3 during APEs, and these elevated concentrations coincided with increased SO2 and monoterpene concentrations, and led to a factor of two increase in CCN concentrations at 0.5% supersaturation. The APEs were simulated using the regional WRF-Chem model, which was extended to account for ultrafine particle sizes starting at 1 nm in diameter, to include an empirical activation nucleation scheme in the planetary boundary layer, and to explicitly simulate the subsequent growth of Aitken particles by condensation of organic and inorganic vapors. Comparisons with aerosol size distribution measurements showed that simulations using the activation nucleation parameterization reasonably captured aerosol number concentrations and size distribution during APEs, as well as ground level CCN concentrations. Results suggest that sulfuric acid from anthropogenic SO2 triggers APEs, and that the condensation of monoterpene oxidation products onto freshly nucleated particles drives their growth. The simulated growth rate of 3.4 nm h−1 for small particles (4–30 nm in diameter) was comparable to the measured average value of 2.3 nm h−1. Model results also suggest that the presence of APEs tends to modify the composition of sub-100 nm diameter particles, leading to generally higher absolute mass concentrations of sulfate as well as organic aerosols with a higher sulfate content. Sensitivity simulations suggest that the representation of nucleation processes in the model largely influences the predicted number concentrations and thus CCN concentrations. We estimate that nucleation contributes to 65% of surface CCN at 0.5% supersaturation in this pine forest environment.
Towards a consistent eddy-covariance processing: an intercomparison of EddyPro and TK3
Authors: Fratini G. , Mauder M.
Published: March 2014

Abstract. A comparison of two popular eddy-covariance (EC) software packages is presented, namely EddyPro and TK3. Two about one-month long test datasets were processed, representing typical instrumental setups, i.e. CSAT3/LI-7500 above grassland and Solent R3/LI-6262 above a forest. The resulting fluxes and quality flags were compared. Achieving a satisfying agreement and understanding residual discrepancies required several iterations and interventions of different nature, spanning from simple software reconfiguration to actual code manipulations. In this paper, we document our comparison exercise and show that the two software packages can provide utterly satisfying agreement when properly configured. Our main aim, however, is to stress the complexity of performing a rigorous comparison of EC software. We show that discriminating actual discrepancies in the results from inconsistencies in the software configuration requires deep knowledge of both software packages and of the eddy-covariance method itself. In some instances, it may be even beyond the possibility of the investigator who does not control the source code. Being the developers of EddyPro and TK3, we could discuss the comparison at all levels of details and this proved necessary to achieve a full understanding. As a further consequence, we also suggest that, to the aim of assuring consistency and comparability of centralized flux databases, and for a confident use of eddy fluxes in synthesis studies on the regional, continental and global scale, researchers rely on established software, notably those that have been extensively validated in documented intercomparisons.
On the clustering of winter storm loss events over Germany
Authors: Karremann M. K. , Pinto J. G. , von Bomhard P. J. , Klawa M.
Published: March 2014

Abstract. During the last decades, several windstorm series hit Europe leading to large aggregated losses. Such storm series are examples of serial clustering of extreme cyclones, presenting a considerable risk for the insurance industry. Clustering of events and return periods of storm series for Germany are quantified based on potential losses using empirical models. Two reanalysis datasets and observations from German weather stations are considered for 30 winters. Histograms of events exceeding selected return levels (1, 2 and 5 year) are derived. Return periods of historical storm series are estimated based on the Poisson and the negative Binomial distributions. Over 4000 years of global circulation model simulations forced with current climate conditions are analysed to provide a better assessment of historical return periods. Estimations differ between distributions, for example 40 to 65 years for the 1990 series. For such less frequent series, estimates obtained with the Poisson distribution clearly deviate from empirical data. The negative Binomial distribution provides better estimates, even though a sensitivity to return level and dataset is identified. The consideration of GCM data permits a strong reduction of uncertainties. The present results support the importance of considering explicitly clustering of losses for an adequate risk assessment for economical applications.
Characterization of hydrochars produced by hydrothermal carbonization of rice husk
Authors: Kalderis D. , Kotti M. S. , Méndez A. , Gascó G.
Published: March 2014

Abstract. Biochar is the carbon-rich product obtained when biomass, such as wood, manure or leaves, is heated in a closed container with little or no available air. In more technical terms, biochar is produced by so-called thermal decomposition of organic material under limited supply of oxygen (O2), and at relatively low temperatures (<700 °C). Hydrochar differentiates from biochar because it is produced in an aqueous environment, at lower temperatures and longer retention times. This work describes the production of hydrochar from rice husks using a simple, safe and environmentally-friendly experimental set-up, previously used for degradation of various wastewaters. Hydrochars were obtained at 200°C and 300°C and at residence times ranging from 2 to 16 h. All samples were then characterized in terms of yield, surface area, pH, conductivity and elemental analysis and two of them were selected for further testing with respect to heating values and heavy metal content.
Evaluation of Model Wheat/Hemp Composites
Authors: Švec Ivan , Hrušková Marie
Published: March 2014

Model cereal blends were prepared from commercial wheat fine flour and 5 samples of hemp flour (HF), including fine (2 of conventional form, 1 of organic form) and wholemeal type (2 of conventional form). Wheat flour was substituted in 4 levels (5, 10, 15, 20%). HF addition has increased protein content independently on tested hemp flour form or type. Partial model cereal blends could be distinguished according to protein quality (Zeleny test values), especially between fine and wholemeal HF type. Both flour types affected also amylolytic activity, for which a relationship between hemp addition and determined level of Falling Number was confirmed for all five model cereal blends. Solvent retention capacity profiles (SRC) of partial models were influenced by both HF form and type, as well as by its addition level. Between both mentioned groups of quality features, significant correlation were proved - relationships among protein content/quality and lactic acid SRC were verifiable on p <0.01 (-0.58, 0.91, respectively). By performed ANOVA, a possibility to distinguish the HF form used in model cereal blend according to the lactic acid SRC and the water SRC was demonstrated. Comparing partial cereal models containing fine and wholemeal hemp type, HF addition level demonstrated its impact on the sodium carbonate SRC and the water acid SRC.
Babilonia, ida y vuelta: del rey arquitecto al arquitecto rey
Authors: Sanmartín Joaquín
Published: March 2014

Los (pocos) reyes-arquitecto mesopotámicos que –para acercarse a los dioses– recurrieron al signo DINGIR “estrella” coinciden en un vértice con los (muchos)arquitectos-rey del (post)modernismo: su vocación estelar. El star system de unos y de otros, reyes-arquitecto o arquitectos-rey, tiende sus puentes a través de tres mil y pico de años de historia.

The (few) Mesopotamian architect-kings who -approaching to gods- used the sign DINGIR “star” happen to meet with the (many) king-architects of the (post)modernism in one point: his stellar vocation. The star system of ones and others, architect-kings or king-architects, tend bridges across more than three thousand years of history.
Aprendiendo del Este
Authors: Azara Nicolás Pedro
Published: March 2014

Aunque ya en el siglo XVIII, con el debilitamiento del Imperio Otomano, los viajes de aventureros europeos a las tierras mencionadas por la Biblia (Asiria y Babilonia) aumentaron, fueron las Guerras de Crimea entre los Imperios Ruso y Otomano, en 1851, y entre los Imperios Persa y Otomano, pocos años más tarde, los que permitieron la llegada de arqueólogos occidentales al Próximo Oriente. Éstos, en efecto, eran militares, que acudían para apoyar a los poderes otomano o persa en función de los intereses en la zona, cuyo control era imprescindible para los desplazamientos entre Europa y las colonias británicas, francesas y alemanas de la India y de Indochina. Esos arqueólogos-militares, que necesitaban trazar planos detallados para las campañas militares y arqueológicas, hallaron las mejores condiciones para iniciar las primeras excavaciones, financiadas por gobiernos y museos públicos británicos y franceses. El Imperio Germánico se incorporó a la conquista territorial y las exploraciones a finales del siglo XIX, tratando de recuperar el tiempo perdido. Finalmente, el siglo XX vio llegar a los arqueólogos norteamericanos enviados por grandes universidades. Las misiones fueron facilitadas con la desmembración del Imperio Otomano y la transformación de los territorios árabes del Imperio en colonias británicas y francesas, lo que aceleró el transvase de piezas hacia Occidente hasta finales de la Segunda Guerra Mundial, cuando la creación de los primeros estados árabes estableció nuevas reglas para la exploración y el reparto. Este número monográfico de la revista DC papers estudiará las estrechas relaciones entre el dominio colonial y la arqueología, en busca de las “raíces” de la cultura europea, que tenían que ser sumerias y no acadias, asirias o babilónicas, unas culturas semitas (como la hebrea) rechazadas por arqueólogos germánicos, sobre todo, en los años veinte y treinta.
The Future of High School Mathematics
Authors: Fey Jim , Garfunkel Sol , Briars Diane , Isaacs Andy , Pollak Henry , Robinson Eric , Scheaffer Richard , Schoenfeld Alan , Seeley Cathy , Teague Dan , Usiskin Zalman
Published: March 2014

Countries that have made progress on international assessments of mathematics achievement have national consensus on goals and sustained commitment to change over time. The Common Core State Standards provide a framework for such effort in the U. S., if we focus on five key elements of curriculum, teaching, and assessment.
Algebra Homework: A Sandwich!
Authors: Jackson D. Bruce
Published: March 2014

Given two slices of bread—a problem and the answer—students fill in the fixings: their own mathematics reasoning.
Learning Algebra from Worked Examples
Authors: Lange Karin E. , Booth Julie L. , Newton Kristie J.
Published: March 2014

Presenting examples of both correctly and incorrectly worked solutions is a practical classroom strategy that helps students counter misconceptions about algebra.
Grass for Goats (The Silo Version)
Authors: Havens Rick
Published: March 2014

The Grazing Goat problem, familiar to many teachers and students, has several variations. The version presented here provides a rich opportunity for engaging students in a project spanning several weeks. Three solutions are discussed: one suitable for a calculus class, one suitable for a geometry class, and one suitable for a precalculus class. Although we start with a calculus approach, most of the article uses only algebra and geometry concepts. Also discussed are the didactics of using projects to open ever-larger fields of mathematics to students.
Problem Solve with Presidential Data
Authors: Patterson Lynn G. , Patterson Kadie L.
Published: March 2014

An engaging activity analyzing the average age of U.S. presidents not only integrates history and mathematics but also examines measures of central tendency and its appropriate uses.
Learning What Works: Promoting Small-Group Discussions
Authors: DeJarnette Anna F. , Dao Jennifer N. , González Gloriana
Published: March 2014

Elicit productive discourse from students as they work through a bicycle rate problem.
Teaching Mathematics through Multicultural Literature
Authors: Iliev Nevin , D'Angelo Frank
Published: March 2014

Enable children of all backgrounds to move beyond their current knowledge base and make culturally relevant mathematical connections.
An Induced Pluripotent Stem Cell Model of Hypoplastic Left Heart Syndrome (HLHS) Reveals Multiple Expression and Functional Differences in HLHS-Derived Cardiac Myocytes
Authors: Jiang Yan , Habibollah Saba , Tilgner Katarzyna , Collin Joseph , Barta Tomas , Al-Aama Jumana Yousuf , Tesarov Lenka , Hussain Rafiqul , Trafford Andrew W. , Kirkwood Graham , Sernagor Evelyne , Eleftheriou Cyril G. , Przyborski Stefan , Stojković Miodrag , Lako Majlinda , Keavney Bernard , Armstrong Lyle
Published: March 2014

Hypoplastic left heart syndrome (HLHS) is a serious congenital cardiovascular malformation resulting in hypoplasia or atresia of the left ventricle, ascending aorta, and aortic and mitral valves. Diminished flow through the left side of the heart is clearly a key contributor to the condition, but any myocardial susceptibility component is as yet undefined. Using recent advances in the field of induced pluripotent stem cells (iPSCs), we have been able to generate an iPSC model of HLHS malformation and characterize the properties of cardiac myocytes (CMs) differentiated from these and control-iPSC lines. Differentiation of HLHS-iPSCs to cardiac lineages revealed changes in the expression of key cardiac markers and a lower ability to give rise to beating clusters when compared with control-iPSCs and human embryonic stem cells (hESCs). HLHS-iPSC-derived CMs show a lower level of myofibrillar organization, persistence of a fetal gene expression pattern, and changes in commitment to ventricular versus atrial lineages, and they display different calcium transient patterns and electrophysiological responses to caffeine and β-adrenergic antagonists when compared with hESC- and control-iPSC-derived CMs, suggesting that alternative mechanisms to release calcium from intracellular stores such as the inositol trisphosphate receptor may exist in HLHS in addition to the ryanodine receptor thought to function in control-iPSC-derived CMs. Together our findings demonstrate that CMs derived from an HLHS patient demonstrate a number of marker expression and functional differences to hESC/control iPSC-derived CMs, thus providing some evidence that cardiomyocyte-specific factors may influence the risk of HLHS.
Relocalisations autochtones et ethnogenèse missionnaire à la frontière sud des empires ibériques
Authors: Wilde Guillermo , Laugrand Frédéric
Published: March 2014

Cet article propose une description et une analyse du processus de formation des communautés guaranies à la frontière des empires ibériques au xviie siècle, sur la base d’un nouveau modèle missionnaire introduit par les prêtres de la Compagnie de Jésus. Ledit modèle impliquait la relocalisation de populations originaires de diverses régions durant une période de cent cinquante ans et une concentration des villages de mission (reducciones) qui répondait elle-même à des paramètres économiques, politiques et culturels uniformes. L’auteur analyse d’abord la politique de ségrégation des populations telle qu’elle a été appliquée dans la région et les déplacements de population durant la formation des réductions au cours du xviie siècle, puis il étudie les transformations qui ont résulté de ce processus par rapport à l’organisation politique autochtone qui préexistait. La dernière section de l’article examine les mécanismes de l’actualisation de l’hétérogénéité interne dans les villages missionnaires, en tenant compte de la persistance des anciennes logiques de mobilité, de parenté et de leadership, lesquelles ont été en quelque sorte recyclées durant le processus d’adaptation.
« South camp was our home »
Authors: Dupré Florence
Published: March 2014

Les déplacements forcés de populations qui sont au coeur des politiques de sédentarisation à l’origine de la création des villes et des villages de l’Arctique canadien, ont eu à partir des années 1950 des conséquences significatives sur l’organisation sociale des groupes inuits. D’une importance majeure dans la construction des identités contemporaines, ils sont aujourd’hui la source de nouveaux déplacements et de stratégies d’occupation et d’appropriation du territoire à l’échelle communautaire et régionale. Cette note de recherche est consacrée à ce que les archives identifient comme la « relocalisation » du camp méridional des îles Belcher (Baie d’Hudson, Nunavut) au nord de l’archipel en 1971. À partir de témoignages de Qikirtamiuts déplacés et de chercheurs engagés dans le processus, l’auteure explore quelques aspects de la genèse et du déroulement de cette « relocalisation » afin de mettre en perspective certaines des dynamiques communautaires contemporaines liées au déplacement des familles.
Migrations et propriété foncière dans l’altiplano occidental du Guatemala
Authors: Hermesse Julie
Published: March 2014

Cet article a comme objectif de présenter, à partir d’une approche historique sur la propriété terrienne, l’évolution conjointe des modes de mobilité choisis par les populations de l’altiplano occidental du Guatemala ou imposés à celles-ci. Les données générales sur l’histoire du foncier et des mobilités propres à la région de l’Occident sont articulées à des données locales recueillies par une recherche ethnographique dans la municipalité de San Martín Sacatepéquez. La notion de territoire désigne un système d’appropriation de l’espace qui présente des aspects tant économiques que symboliques de l’histoire et de la culture. Dans sa dimension économique, la terre reste le moyen par excellence de la survie matérielle de la société guatémaltèque. Elle est aussi le fondement de l’identité paysanne autochtone. Significatif aussi de l’enracinement à la terre des ancêtres, historiquement, les populations amérindiennes ont été actrices de phénomènes migratoires saisonniers et non permanents. Les migrations transnationales actuelles témoignent de l’évolution historique des phénomènes de mobilité qui doit être analysée en regard des transformations foncières et des contraintes économiques. Dans sa dimension symbolique, la terre porte, entre autres, l’image de la spoliation.
Evolution of extreme resistance to ionizing radiation via genetic adaptation of DNA repair
Authors: Byrne Rose T , Klingele Audrey J , Cabot Eric L , Schackwitz Wendy S , Martin Jeffrey A , Martin Joel , Wang Zhong , Wood Elizabeth A , Pennacchio Christa , Pennacchio Len A , Perna Nicole T , Battista John R , Cox Michael M
Published: March 2014

By directed evolution in the laboratory, we previously generated populations of Escherichia coli that exhibit a complex new phenotype, extreme resistance to ionizing radiation (IR). The molecular basis of this extremophile phenotype, involving strain isolates with a 3-4 order of magnitude increase in IR resistance at 3000 Gy, is now addressed. Of 69 mutations identified in one of our most highly adapted isolates, functional experiments demonstrate that the IR resistance phenotype is almost entirely accounted for by only three of these nucleotide changes, in the DNA metabolism genes recA, dnaB, and yfjK. Four additional genetic changes make small but measurable contributions. Whereas multiple contributions to IR resistance are evident in this study, our results highlight a particular adaptation mechanism not adequately considered in studies to date: Genetic innovations involving pre-existing DNA repair functions can play a predominant role in the acquisition of an IR resistance phenotype.
Comparison and distribution of minimum operation voltage in fully depleted silicon-on-thin-buried-oxide and bulk static random access memory cells
Authors: Mizutani Tomoko , Yamamoto Yoshiki , Makiyama Hideki , Shinohara Hirofumi , Iwamatsu Toshiaki , Oda Hidekazu , Sugii Nobuyuki , Hiramoto Toshiro
Published: March 2014

The minimum operation voltage (V
min) of intrinsic channel fully depleted (FD) silicon-on-thin-buried-oxide (SOTB) static random access memory (SRAM) cells are measured and compared with those of conventional bulk SRAM cells in order to directly compare the worst cells. It is confirmed that the worst V
min of 1 kbit SOTB SRAM cells is half that of 1 kbit bulk cells. The distribution of V
min of 48 kbit SOTB and bulk SRAM cells are also measured and compared. The results show a great advantage of SOTB SRAM cells for lower power and lower voltage operation upon introducing SOTB, because of reduced V
TH variability.
Enhanced light harvesting of nitride-based nanopillars covered with ZnO using indium–tin oxide nanowhiskers
Authors: Hsu Lung-Hsing , Lin Chien-Chung , Lee Hsin-Ying , Huang Jhih-Kai , Han Hau-Vei , Tsai Yu-Lin , Yu Peichen , Kuo Hao-Chung , Lee Ching-Ting
Published: March 2014

Nitride-based nanopillars were successfully fabricated by nanoimprint lithography. A nanowhisker of indium–tin oxide (ITO) deposited by on oblique evaporation method was investigated in nitride-based nanopillars and thin ZnO layers grown by atomic layer deposition (ALD). From the results of field-emission scanning electron microscopy (SEM) measurement, it was found that ITO whiskers grew on nitride-based nanopillars covered with ZnO. Moreover, from the results of UV–visible spectrophotometry and bidirectional reflectance distribution function (BRDF) measurements, it was found that this hybrid structure of ITO nanowhiskers above a ZnO medium enhanced the broadband and angle-independent antireflection in the range between 380 and 600 nm. We used the hybrid design of the ITO/ZnO structure to achieve the lowest reflectance value between 3.8 and 10.9% in a quantum well absorption range.
Pressure Studies of Tunneling between Two-Dimensional Electron Gas Systems
Authors: Suski T. , Smoliner J. , Gschößl C. , Demmerle W. , Böhm G. , Weimann G.
Published: March 2014

We have investigated the tunneling processes between 2D electron gas systems separated by a AlGaAs barrier. Hydrostatic pressure and illumination was used to modify th potential profiles determining the subband energies and the corresponding spacing between the observed subband resonance peaks. With increasing level of illumination, the spacing between the observed subband resonances are decreased through an reduced depletion field, while the electron concentration is kept approximately constant through the choice of appropriate pressure values. In addition, LO-phonon related satellites of the original subband resonances are observed, which indicate that LO-phonon assisted processes are the dominant scattering mechanisms in this regime. At high depletion fields, however, electron-plasmon interaction is identified as relevant scattering process. Using the amplitude of the phonon satellites as a reference, the field dependent scattering rate for this process is determined.
Electron Transport in Antidot GaAs/AlGaAs Structures under Hydrostatic Pressure
Authors: Suski T. , Berthold G. , Smoliner J. , Maschek R. , Gornik E. , Böhm G. , Weimann G.
Published: March 2014

On GaAs/AlGaAs heterostructures, the magnetotransport of a two dimensional electron gas in a modulated potential is investigated as a function of hydrostatic pressure and gate voltage. In the transition region between a lateral surface superlattice and an antidot structure, both gate voltage and hydrostatic pressure was used to change the electron density. The application of pressure leads to significant changes in the occupation of donor states in the AlGaAs barrier. As a result, the potential modulation is decreased. Above a critical pressure, where the Fermi level becomes lower than the potential modulation, the formation of antidots is evident as a sudden decrease of the electron mobility. In antidot regime, the change of the mobility as a function of the electron density is much weaker in pressurized systems than in comparable gated structures. This effect is consistently explained by the screening of scattering centers due to the pressure induced formation of dipoles consisting of positive and negative donors inside the AlGaAs barrier.
Pressure Dependence of Band Discontinuity in GaAs/AlInP Quantum Well Structures
Authors: Nakayama Takeshi , Minami Fujio , Nagao Satoru , Inoue Yuichi , Gotoh Hideki
Published: March 2014

We have performed high-pressure photoluminescence measurements on GaAs/AlInP quantum wells of widths 10 to 100 Å at liquid helium temperatures. It is found from the pressure coefficient that the X minima in the AlInP become lower than the confined Γ state in the GaAs wells with widths of less than 30 Å. The zero-pressure extrapo-lation of the AlInP(X) to GaAs(Γ) transitions yields a 680 meV valence-band offset and a 770 meV conduction-band offset.
Growth and Characterization of Strained-Layer Quantum Wells with Wide Gap ZnCdSSe Alloy System
Authors: Ichino Kunio , Kawakami Yoichi , Fujita Shizuo , Fujita Shigeo
Published: March 2014

A guideline for designing laser structures with strained-layer quantum wells (QWs) of ZnCdSSe alloy system is discussed. Growth control and optical properties of ZnCdSe/ZnSSe QWs coherently grown on GaAs substrates strongly suggest their promising potential for blue-green region optoelectronic applications. For ultraviolet laser structures, ZnCdSSe/ZnSSe or ZnCdSSe/ZnCdS QWs coherently grown on GaP are proposed.
Lattice Strain in Si1-xGex Alloy and Si/Si1-xGex Superlattice
Authors: Iwasa Kazuhiro , Takarabe Kenichi , Minomura Sigeru , Aketagawa Kenichi , Sakai Junrou
Published: March 2014

Si1-xGex alloy and Si/Si1-xGex superlattice are coherently grown on Si substrates by UHV-CVD(Gas-Source MBE). Lattice strain is investigated by double crystal X-ray diffraction, Raman scattering and Photoluminescence experiments. By using the data of (004) and (113) diffraction lines, the c-axis of Si1-xGex alloy is evaluated to be expanded by 0.69% than the c-axis of Si substrate. For the case of Si/Si1-xGex superlattice the c-axis of Si1-xGex layer in superlattice is determined to have the same value with that of Si1-xGex alloy grown on Si substrate by the kinematical simulation of superlattice satellites, and the c-axis of Si layer in superlattice has the same value with that of Si substrate. The backscattering Raman spectra of two samples are identical with the frequencies of Si-Si, Si-Ge and Ge-Ge modes. In the 4.2 K-photoluminescence experiments, the same spectral features observed in the Si1-xGex alloy layer are appeared also in the Si/Si1-xGex superlattice, however the photon energy of luminescence is moved to lower by 10 meV. This indicates that the Si/Si1-xGex superlattice has the type II band line-up.
Studies of Amorphous Semiconductors under Pressure
Authors: Davis Edward A.
Published: March 2014

Experimental data on the effect of pressure on the optical and electrical properties of a variety of amorphous semiconductors are presented. The results are discussed in terms of coordination numbers, the type of chemical bonding and the network dimensionality, all of which play a role in determining the sign and magnitude of the effects.
Pressure Dependence of Variable-Range Hopping Conduction in Amorphous Germanium Alloys
Authors: Chen Jian-Qiang , Katayama Yoshinori , Tsuji Kazuhiko
Published: March 2014

The electrical conductivity σ and the thermopower S of amorphous germanium-copper alloys have been measured at pressures up to 10 GPa and temperatures down to 80 K using a diamond anvil cell. The temperature dependence of σ from 80 K to 310 K obeys the Mott's T
-1/4 relation for variable-range hopping of carriers in the localized states at the Fermi level. A parameter for temperature variation of σ, T
0
1/4 increases below 2 GPa, and decreases above 2 GPa. The thermopower S has a positive value, and also shows a maximum at 2GPa. From these experimental results, the pressure dependence of the density of states for amorphous germanium alloy is discussed.
DX Centers in AlGaAs:Si under Pressure: Electron Statistics for Negative-U and Multilevel Model
Authors: Contreras S. , Lorenzini P. , Mosser V. , Robert J. L. , Piotrzkowski R.
Published: March 2014

It has been established that the DX center presents several configurations in the GaAlAs alloy, depending on the local environment of the impurity atom in the relaxed ground state. A statistics including these 4 configurations is developed in the frame of the negative-U model and is used to explain transport experiments under low magnetic field and high hydrostatic pressure.
We show that a combination of emission transients experiment and Hall measurements at thermal equilibrium under pressure gives access to a quantitative determination of the thermal energies for the different configurations of the DX center.
Probing the DX Center in GaAs and Related Alloys by Capacitance Transient Measurements under Stress
Authors: Li Ming-Fu , Yu Peter Y.
Published: March 2014

This paper will review some recent results in the study of the DX center in GaAs and AlGaAs using capacitance transient techniques under hydrostatic and uniaxial stress. These measurements have established the DX center as the deep state of substitutional donors in GaAs or AlGaAs which is lowered into the band gap by alloying or pressure.When compared with the predictions of various models of the DX center, the stress results are shown to be consistent with the DX centers having a two electrons negatively charged ground state (negative U).Models of the DX center as effective mass state of donor associated with the L conduction band valleys are found to be incon-sistent with stress experiments.
Structural Phase Transitions in Selenium up to 150 GPa
Authors: Akahama Yuichi , Kobayashi Mototada , Kawamura Haruki
Published: March 2014

High-pressure X-ray diffraction experiments for selenium in a wide pressure range up to 150 GPa have been carried out and five structural phase transitions have been revealed: from hexagonal Se (Se-I) to an intermediate (Se-II) at 14 GPa, to base-centered monoclinic (Se-III) at 23 GPa, to base-centered orthorhombic (Se-IV) at 28 GPa, to β-Po type primitive rhombohedral (Se-V) at 60 GPa and further to body-centered cubic phase (Se-VI) at 140 GPa. The structural sequence corresponds to a change toward to higher symmetry and exhibits a similarity with that of Te.
Multiplicity and Lattice Relaxation of DX Center in AlGaAs:Si Studied by Electron Emission Spectra under Pressure
Authors: Takarabe Kenichi , Ashizawa Hiroaki , Minomura Shigeru , Kato Hiromu , Watanabe Yasutaka , Matsuda Koichirou
Published: March 2014

DX center in Al0.3Ga0.7As:Si consists of four components, of which each component has the same thermal activation energy(0.41±0.02eV). The activation energy and emission-rate show no changes on pressure. One significant implication is that no lattice deformation occurs upon an electron emission.