bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison between the Microstructure of the Mineral Phase in Two Types of Composite Beads for Bone Regeneration
Authors: Petre Daniela G. , Serafim Andra , Lungu Adriana , Vasile Eugeniu , Cristescu Ioan , Istodorescu Mircea
Published: June 2014

Apatite containing-polymer beads have been prepared using two methods. The first series of scaffolds is obtained using an effortless procedure consisting in mixing the mineral phase in the polymer precursors, followed by crosslinking. The resulting materials contained agglomerates of inorganic particles. The second series of materials is generated through a more complex synthesis involving the alternate Ca2+/PO43- soaking of the polymer beads. This leads to formation of nanometric apatite phase homogeneously distributed within and on the surface of the polymer substrates. The resulting materials have been characterized by infrared spectrometry, X-ray diffraction and scanning electron microscopy.
Effect of Silicon-Doped Calcium Phosphate Bone Substitutes on Bone Formation and Osteoblastic Phenotype Expression In Vivo
Authors: Knabe Christine , Lopez Heredia Marco , Barnemitz Dirk , Genzel Antje , Peters Fabian , Hübner Wolf Dietrich
Published: June 2014

This study evaluates the effect of two novel particulate silicon-doped calcium phosphate graft materials as compared to the currently clinically used material β-TCP on osteogenesis and bone formation after implantation in critical-size defects the sheep scapula. These materials were developed in order to create biodegradable bone substitute materials that degrade rapidly, but still stimulate osteogenesis at the same time, thereby resulting in bone repair and regeneration with fully functional bone tissue. All bone substitute materials studied facilitated excellent bony regeneration of critical-size defects in the sheep scapula. Of the three grafting materials studied, the calcium alkali orthophosphate material with the crystalline phase Ca2KNa (PO4)2, with a small amorphous portion containing magnesium potassium phosphate and a small addition of sodium magnesium silicate had the greatest stimulatory effect on bone formation and expression of osteogenic markers, while exhibiting the highest biodegradability.
Influence of Time on Thermal Oxidation of CP-Ti Grade II at 850 °C
Authors: Istrate Bogdan , Munteanu Corneliu , Strugaru Sorin Iacob , Barca Alexandru , Biniuc Carmen , Carmen Iulia Crimu
Published: June 2014

The objective of this work is to understand the influence of time on thermal oxidation of CP-Ti Grade II at 850 oC. Thermal treatments were performed for 5 minutes, 15 minutes, 30 minutes, 60 minutes and 120 minutes of isothermal stage. The response of titanium to oxidation at same temperatures and various timings has been investigated, in terms of layer thickness, phase evolution. A variety of experimental and analytical techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM) and ball cratering test have been used to characterize the result of thermal oxidized surfaces. The results showed that oxygen diffused on Ti structure can produce a thick oxide layer with rutile (TiO2) between 3,50 and 10,34 microns, which exhibited good adhesion with the substrate.
SEM Characterisation of a Tricalcium Phosphate – Chitosan - PMMA Cement
Authors: Mahjoub Hella , Sarosi Codruța , Orasan Olga , Saplonţai-Pop Aniela
Published: June 2014

Synthetic Polymers, both organic and inorganic, are used in a wide variety of biomedical applications. The polymers can be biodegradable or nondegradable. Chitosan (CH), which is a naturally biodegradable, non-toxic biopolymer obtained by the deacetylation of chitin, has been demonstrated to have an intrinsic activity against a wide spectrum of bacteria, filamentous fungi and yeast. Several investigators have studied reinforced tricalcium phosphate (TCP), Chitosan, polymethylmethacrylate (PMMA)/methyl methacrylate (MMA) as potential cement. In fact addition of TCP with chitosan to the cement can improve biocompatibility and also enhance the mechanical properties of the cement because of its both biocompatibility and osteoconductivity properties. Crystalline phase and microstructure of the cement with hydroxyapatite - poly (methyl-methacrylate) were characterized by scanning electron microscopy (SEM; FEI Company), with the purpose to draw solid conclusions about the influence of the particles size, form and uniform mixing on the chemical process. We acquired PMMA sorted according to granulometric size.
Synthesis of Calcium Carbonate Biological Materials: How Many Proteins are Needed?
Authors: Marin Frédéric , Le Roy Nathalie , Marie Benjamin , Ramos-Silva Paula , Wolf Stephan , Benhamada Sana , Guichard Nathalie , Immel Françoise
Published: June 2014

In Nature, calcium carbonate biomineralizations are the most abundant mineralized structures of biological origin. Because many exhibit remarkable characteristics, several attempts have been made to use them as substitution materials for bone reconstruction or as models for generating biomimetic composites that exhibit tailored properties. CaCO3biomineralizations contain small amounts of amalgamate of proteins and polysaccharides that are secreted during the calcification process. They contribute to control the morphology of the crystallites and to spatially organize them in well-defined microstructures. These macromolecules, collectively defined as the skeletal matrix, have been the focus of a large number of studies aiming at synthesizingin vitrobiomimetic materials, according to a bottom-up approach. However, recent proteomic investigations performed on the organic matrices associated to mollusc shells or to coral skeletons have quashed our hopes to generate, with only few macromolecular ingredients, biomimetic materials with properties approaching to those of natural biominerals. As a mean value, each matrix comprises a minimum of few tens of different proteins that seem to be strictly associated to calcium carbonate biominerals. Among the proteins that are currently detected, one finds RLCDs-containing proteins (Repetitive-Low-Complexity Domains), enzymes, proteins with protease inhibitors domains and at last, proteins that contains typical ECM (ExtraCellular Matrix) domains. Today, we still do not understand how the skeletal matrix works, and unveiling its complex functioning is one of the challenges for the coming decade, both from fundamental and applied viewpoints. Is it realistic to attempt generating abiotically, in a test tube at room temperature, biomimetic composites that mimic natural biomineralizations in their properties? If so, and by supposing that we know the individual functions of all the components of the matrix, is there a minimal number of proteins required for producingin vitrocalcium carbonate biomaterials that approximate natural biominerals? These issues are of importance for the future research directions in biomaterials science.
Tribological Tests and SEM Analysis for Titanium Oxide Layers
Authors: Istrate Bogdan , Munteanu Corneliu , Luca Dorin , Earar Kamel , Barca Eduard Sebastian , Antoniac Iulian Vasile
Published: June 2014

The use of titanium and its alloys is currently considered very attractive for dental implants, with the improvement of physical properties, corrosion resistance and biocompatibility of them. These properties are attributed to the formation of titanium dioxide (TiO2) as a protective layer. The aim of this work is to understand the influence of time on heat treatment of CP-Ti Grade II at 850 oC. Heat treatments were performed for 5, 15, 30, 60 and 120 minutes. The response of titanium to oxidation at same temperatures and various timings has been investigated, in terms of wear resistance, surface morphology and oxide layer substrate adhesion. A variety of experimental and analytical techniques including scanning electron microscopy (SEM) and tribological testing have been used to characterize the resultant thermal oxidized surfaces. The results showed that oxygen diffused Ti structure can produce compact layer (TiO2), which exhibited good adhesion with the substrate at 30 minutes and 120 minutes of heat treatment.
Alveolar Bone Augmentation
Authors: Dimova Cena , Papakoca Kiro , Papakoca Velko
Published: June 2014

Bones and teeth are the only structureswithin the body where calciumandphosphate participate asfunctional pillars. Despite their mineralnature, both organs are vital and dynamic. The aim was to remark the indications for alveolar augmentation after tooth extraction and prior the placement of endoosseous dental implants. The autograft, allograft, alloplast, and xenograftmaterials all have reported success, alone or in combination,for particulate bone augmentation. Theparticulate autograft is the gold standard for mostcraniofacial bone grafting, including the treatmentof dental implant–related defects. Advantages of alveolar ridge augmentation with sufficient bone volume to adjust for uncompromised and esthetic implant placement, renders these procedures more than effective for majority of patients. Surgical reconstruction of the tissues and the procedure of ridge augmentation and subsequent placement of dental implant are necessary.
Dual Function of CD70 in Viral Infection: Modulator of Early Cytokine Responses and Activator of Adaptive Responses
Authors: Allam Atef , Swiecki Melissa , Vermi William , Ashwell Jonathan D. , Colonna Marco
Published: June 2014

The role of the TNF family member CD70 in adaptive T cell responses has been intensively studied, but its function in innate responses is still under investigation. In this study, we show that CD70 inhibits the early innate response to murine CMV (MCMV) but is essential for the optimal generation of virus-specific CD8 T cells. CD70−/− mice reacted to MCMV infection with a robust type I IFN and proinflammatory cytokine response. This response was sufficient for initial control of MCMV, although at later time points, CD70−/− mice became more susceptible to MCMV infection. The heightened cytokine response during the early phase of MCMV infection in CD70−/− mice was paralleled by a reduction in regulatory T cells (Treg). Treg from naive CD70−/− mice were not as efficient at suppressing T cell proliferation compared with Treg from naive wild-type mice, and depletion of Treg during MCMV infection in Foxp3–diphtheria toxin receptor mice or in wild-type mice recapitulated the phenotype observed in CD70−/− mice. Our study demonstrates that although CD70 is required for the activation of the antiviral adaptive response, it has a regulatory role in early cytokine responses to viruses such as MCMV, possibly through maintenance of Treg survival and function.
The Peritrophic Matrix Mediates Differential Infection Outcomes in the Tsetse Fly Gut following Challenge with Commensal, Pathogenic, and Parasitic Microbes
Authors: Weiss Brian L. , Savage Amy F. , Griffith Bridget C. , Wu Yineng , Aksoy Serap
Published: June 2014

The insect gut is lined by a protective, chitinous peritrophic matrix (PM) that separates immunoreactive epithelial cells from microbes present within the luminal contents. Tsetse flies (Glossina spp.) imbibe vertebrate blood exclusively and can be exposed to foreign microorganisms during the feeding process. We used RNA interference–based reverse genetics to inhibit the production of a structurally robust PM and then observed how this procedure impacted infection outcomes after per os challenge with exogenous bacteria (Enterobacter sp. and Serratia marcescens strain Db11) and parasitic African trypanosomes. Enterobacter and Serratia proliferation was impeded in tsetse that lacked an intact PM because these flies expressed the antimicrobial peptide gene, attacin, earlier in the infection process than did their counterparts that housed a fully developed PM. After challenge with trypanosomes, attacin expression was latent in tsetse that lacked an intact PM, and these flies were thus highly susceptible to parasite infection. Our results suggest that immunodeficiency signaling pathway effectors, as opposed to reactive oxygen intermediates, serve as the first line of defense in tsetse’s gut after the ingestion of exogenous microorganisms. Furthermore, tsetse’s PM is not a physical impediment to infection establishment, but instead serves as a barrier that regulates the fly’s ability to immunologically detect and respond to the presence of these microbes. Collectively, our findings indicate that effective insect antimicrobial responses depend largely upon the coordination of multiple host and microbe-specific developmental factors.
Reactive Oxygen Species– and DNA Damage Response–Dependent NK Cell Activating Ligand Upregulation Occurs at Transcriptional Levels and Requires the Transcriptional Factor E2F1
Authors: Soriani Alessandra , Iannitto Maria Luisa , Ricci Biancamaria , Fionda Cinzia , Malgarini Giulia , Morrone Stefania , Peruzzi Giovanna , Ricciardi Maria Rosaria , Petrucci Maria Teresa , Cippitelli Marco , Santoni Angela
Published: June 2014

Increasing evidence indicates that cancer cell stress induced by chemotherapeutic agents promote antitumor immune responses and contribute to their full clinical efficacy. In this article, we identify the signaling events underlying chemotherapy-induced NKG2D and DNAM-1 ligand expression on multiple myeloma (MM) cells. Our findings indicate that sublethal doses of doxorubicin and melphalan initiate a DNA damage response (DDR) controlling ligand upregulation on MM cell lines and patient-derived malignant plasma cells in Chk1/2-dependent and p53-independent manner. Drug-induced MICA and PVR gene expression are transcriptionally regulated and involve DDR-dependent E2F1 transcription factor activity. We also describe the involvement of changes in the redox state in the control of DDR-dependent upregulation of ligand surface expression and gene transcriptional activity by using the antioxidant agent N-acetyl-l-cysteine. Finally, in accordance with much evidence indicating that DDR and oxidative stress are major determinants of cellular senescence, we found that redox-dependent DDR activation upon chemotherapeutic treatment is critical for MM cell entry in premature senescence and is required for the preferential ligand upregulation on senescent cells, which are preferentially killed by NK cells and trigger potent IFN-γ production. We propose immunogenic senescence as a mechanism that promotes the clearance of drug-treated tumor cells by innate effector lymphocytes, including NK cells.
A Finite-time Condition for Exponential Trichotomy in Infinite Dynamical Systems
Authors: Ducrot Arnaud , Magal Pierre , Seydi Ousmane
Published: June 2014

In this article we study exponential trichotomy for infinite dimensional discrete time dynamical systems. The goal of this article is to prove that finite time exponential trichotomy conditions allow us to derive exponential trichotomy for arbitrary times. We present an application to the case of pseudo orbits in some neighborhood of a normally hyperbolic set.
Seroprevalence of Seven Zoonotic Pathogens in Pregnant Women from the Caribbean
Authors: Wood Heidi , Drebot Michael A. , Dewailly Eric , Dillon Liz , Dimitrova Kristina , Forde Martin , Grolla Allen , Lee Elise , Loftis Amanda , Makowski Kai , Morrison Karen , Robertson Lyndon , Krecek Rosina C.
Published: June 2014

Studies examining the prevalence of zoonotic agents in the Caribbean are very limited. The objective of this study was to examine the seroprevalence of seven zoonotic agents among individuals residing on 10 English-speaking Caribbean countries. Sera from healthy, pregnant women were collected from Antigua-Barbuda, Belize, Bermuda, Dominica, Grenada, Jamaica, Montserrat, St. Kitts-Nevis, St. Lucia, and St. Vincent-Grenadines and tested for the presence of IgG antibodies to dengue virus, hepatitis E virus, hantaviruses, leptospiral agents, spotted fever group rickettsiae (SFGR), typhus group rickettsiae (TGR), and Coxiella burnetii (Q fever). The highest seroprevalence values were observed for dengue virus, SFGR, and leptospirosis, although the lowest seroprevalence values were observed for hepatitis E virus, C. burnetii, and TGR. Antibodies to hantaviruses were not detected in any individuals.
Differential absorption radar techniques – Part 1: Surface pressure
Authors: Millán L. , Lebsock M. , Livesey N. , Tanelli S. , Stephens G.
Published: June 2014

Abstract. Two radar pulses sent at different frequencies near the 60 GHz O2 absorption band can be used to determine surface pressure by measuring the differential absorption on and off the band. Results of inverting synthetic data assuming an airborne radar are presented. The analysis includes the effects of temperature, water vapor, hydrometeors as well as particle size distributions and surface backscatter uncertainties. Results show that an airborne radar (with sensitivity of −20 and 0.05 dBZ speckle and relative calibration uncertainties and a 400 m by 400 m footprint) can estimate surface pressure with a precision of ~ 1.0 hPa and accuracy better than 1.0 hPa for clear-sky and cloudy conditions and better than 3.5 hPa for precipitating conditions. Generally, accuracy would be around 0.5 and 2 hPa for non-precipitating and precipitating conditions, respectively.
FLEXINVERT: an atmospheric Bayesian inversion framework for determining surface fluxes of trace species using an optimized grid
Authors: Thompson R. L. , Stohl A.
Published: June 2014

Abstract. We present a new modular Bayesian inversion framework, called FLEXINVERT, for estimating the surface fluxes of atmospheric trace species. FLEXINVERT can be applied to determine the spatio-temporal flux distribution of any species for which the atmospheric loss (if any) can be described as a linear process and can be used on continental to regional and even local scales with little or no modification. The relationship between changes in atmospheric mixing ratios and fluxes (the so-called source–receptor relationship) is described by a Lagrangian Particle Dispersion Model (LPDM) run in a backwards in time mode. In this study, we use FLEXPART but any LPDM could be used. The framework determines the fluxes on a nested grid of variable resolution, which is optimized based on the source–receptor relationships for the given observation network. Background mixing ratios are determined by coupling FLEXPART to the output of a global Eulerian model (or alternatively, from the observations themselves) and are also optionally optimized in the inversion. Spatial and temporal error correlations in the fluxes are taken into account using a simple model of exponential decay with space and time and, additionally, the aggregation error from the variable grid is accounted for. To demonstrate the use of FLEXINVERT, we present one case study in which methane fluxes are estimated in Europe in 2011 and compare the results to those of an independent inversion ensemble.
Mapping irrigation potential from renewable groundwater in Africa – a quantitative hydrological approach
Authors: Altchenko Y. , Villholth K. G.
Published: June 2014

Abstract. Groundwater provides an important buffer to climate variability in Africa. Yet groundwater irrigation contributes only a relatively little share of cultivated land, approximately 1% (about 2 million hectares) as compared to 14% in Asia. While groundwater is over-exploited for irrigation in many parts in Asia, previous assessments indicate an under-utilized potential in parts of Africa. As opposed to previous country-based estimates, this paper derives a continent-wide, distributed (0.5° spatial resolution) map of groundwater irrigation potential, indicated in terms of fractions of cropland potentially irrigable with renewable groundwater. The method builds on an annual groundwater balance approach using 41 years of data, allocating only that fraction of groundwater recharge that is in excess after satisfying other human needs and environmental requirements, while disregarding any socio-economic and physical constraints in access to the resource. Due to high uncertainty of groundwater environmental needs, three scenarios, leaving 30, 50 and 70% of recharge for the environment, were implemented. Current dominating crops and cropping rotations and associated irrigation requirements in a zonal approach were applied in order to convert recharge excess to potential irrigated cropland. Results show an inhomogeneously distributed groundwater irrigation potential across the continent, even within individual countries, reflecting recharge patterns and presence or absence of cultivated cropland. Results further show that average annual groundwater available for irrigation ranges from 692 to 1644 km3 depending on scenario. The total area of cropland irrigable with groundwater ranges from 27.2 to 64.3 million ha, corresponding to 12.5 to 29.6% of the cropland over the continent. The map is a first assessment that needs to be complimented with assessment of other factors, e.g. hydrogeological conditions, groundwater accessibility, soils, and socio-economic factors as well as more local assessments.
The new role of radio and its public in the age of social network sites
Authors: Bonini Tiziano
Published: June 2014

A culture of co–creation is emerging in art, design, architecture (Armstrong and Stojmirovic, 2011), music, video, literature and other productive fields like manufacturing, urban agriculture and biotech. Many of the tools of production and distribution used by professionals are available to the broader public. Publics are becoming more and more productive (Jenkins, 1992; Arvidsson, 2011). The rise of these phenomena suggests that a new modality of value creation is affirming itself in the information economy (Arvidsson and Colleoni, 2012). This emerging co–creation culture and a new theory of value also affect the radiophonic medium. The combination between radio and social networks sites (SNS) brought to completion a long historical process by virtue of which the distance with the public decreases, as Walter Benjamin already understood in his work on the relation between radio and society. In this paper I will focus on the changes that the publics of radio have undergone in the last stage of this “history of distance”, since they started to use social media, in particular Facebook: change in the publicness of publics; in the value of publics (publics are participating into the production process); in the speaker–to–listener relationship (where a new form of intimacy is becoming predominant) and in the listener–to–listener one; in the role and ethic of the radio producer (which is becoming more curatorial and less productive). To do this I will have to mix two different fields of studies: the radio studies tradition and emerging studies about social media.
Enclosing the public domain: The restriction of public domain books in a digital environment
Authors: Clark Alex , Chawner Brenda
Published: June 2014

This paper explores restrictions that are being applied to New Zealand public domain books once they have been digitized and hosted online. The study assesses access and usage restrictions within six online repositories, using a sample of 100 pre–1890 New Zealand heritage books. The findings indicate that new restrictions are being applied to works no longer protected by copyright. Out of the 50 titles that had been digitized, only three were hosted by repositories that do not restrict any type of subsequent use. Furthermore, 48 percent (24) were subject to access restrictions. Copyright law’s delicate balance between public and private interests is being eroded by the prevalence of online terms and conditions, which invoke the doctrine of contract law in an attempt to restrict the public domain and opt–out of limitations upon copyright. Furthermore, ambiguity surrounding the copyright status of some books is encouraging digitizers to adopt restrictive access policies, even when a work is highly likely to be in the public domain. Unless clear rules of online curatorship are articulated within legislation, previously liberated public domain works are at risk of being restricted by online intermediaries.
Death and the Internet: The implications of the digital afterlife
Authors: Wright Nicola
Published: June 2014

This paper addresses the ways in which our cultural understanding of death is changed by the digital afterlife and the affordances of the Internet. Since the advent of the digital age, we now interact, create and conduct business online leaving a digital footprint that remains even after we die; there is now a growing popular cultural awareness of this and online start–ups have been quick to capitalise on our need to make for provision for our digital assets. Social platforms have allowed for Web memorialisation, emergence of new grieving practices and expansion of traditional mourning rituals, however, there are a number of issues related to digital assets and these online mourning practices. At present, there is no consensus as to how social media company policies on deceased user accounts are handled, an area that is further muddied by legal issues of ownership and privacy. Furthermore user interface design does not currently make provision for the death of users and the social processes around online mourning were found to be complex and at times damaging to the bereaved. The expansion of our digital lives, the end of ‘sequestered death’, new mourning practices and issues associated with these changes, have, this paper argues, expanded, changed, and irreversibly complicated our cultural understanding of death as mediated through the Internet and communication technologies.
The effect of the Internet on civic engagement under authoritarianism: The case of Azerbaijan
Authors: Pearce Katy E. , Freelon Deen , Kendzior Sarah
Published: June 2014

This study examines civic activities under an authoritarian state — Azerbaijan — focusing on how the Internet may influence them. The role of the Internet in political and civic engagement is a subject of debate in any society. But Azerbaijan offers a unique vantage point to study the Internet’s effect on engagement because it views the Internet as an extension of sovereign dominion and controls online discussions. The government maintains the same view of the Internet as it does towards non–governmental engagement: it is unacceptable because it occurs outside state parameters. Using two nationally representative datasets from 2011, logistic regression analysis found that the Internet is associated with public civic engagement (and some forms of private civic engagement) but not with political government engagement. All results were robust to demographic controls, strengthening confidence that the Internet was at least indicative of, if not contributory to, civic life in Azerbaijan outside of the government.
Heteromation and its (dis)contents: The invisible division of labor between humans and machines
Authors: Ekbia Hamid , Nardi Bonnie
Published: June 2014

The division of labor between humans and computer systems has changed along both technical and human dimensions. Technically, there has been a shift from technologies of automation, the aim of which was to disallow human intervention at nearly all points in the system, to technologies of “heteromation” that push critical tasks to end users as indispensable mediators. As this has happened, the large population of human beings who have been driven out by the first type of technology are drawn back into the computational fold by the second type. Turning artificial intelligence on its head, one technology fills the gap created by the other, but with a vengeance that unsettles established mechanisms of reward, fulfillment, and compensation. In this fashion, replacement of human beings and their irrelevance to technological systems has given way to new “modes of engagement” with remarkable social, economic, and ethical implications. In this paper we provide a historical backdrop for heteromation and explore and explicate some of these displacements through analysis of a number of cases, including Mechanical Turk, the video games FoldIt and League of Legends, and social media.
L’intention entrepreneuriale des femmes : le cas de l’Égypte
Authors: Alexandre-Leclair Laurice , Redien-Collot Renaud
Published: June 2014

Mueller (2004) démontre que les intentions entrepreneuriales des femmes sont moindres que celles des hommes surtout dans les pays en voie de développement. Qu’en est-il dans un pays en économie de transition, comme l’Égypte ? Tout en relançant le questionnement de Mueller (2004), cette étude articule une comparaison sexuée et une approche genrée pour mieux comprendre le rôle des rapports hommes/femmes dans la formation de l’intention entrepreneuriale féminine dans une culture donnée. Grâce à une recherche quantitative menée en 2010 auprès de 320 étudiants égyptiens francophones au Caire, les auteurs ont pu démontrer que les étudiantes égyptiennes ont fortement le désir d’entreprendre et de concrétiser assez rapidement leurs projets, qu’elles sont assez confiantes dans leurs compétences à créer et conscientes des obstacles qu’elles rencontreront. La recherche révèle également certaines ambivalences des projets entrepreneuriaux des jeunes égyptiennes liées aux rapports de genre. Notre recherche complète ainsi les conclusions de Mueller (2004) et Langowitz et Minitti (2007). Nous pouvons arguer du fait que dans un pays en économie de transition le déséquilibre des motivations entrepreneuriales des femmes et des hommes est limité.
Rôle déterminant des ressources immatérielles dans la création de valeur dans une PME agroalimentaire de terroir1
Authors: Louzzani Yassine
Published: June 2014

Cette étude vise à analyser le rôle des ressources immatérielles dans la création de valeur dans une entreprise installée dans une zone où le terroir peut être source d’avantages concurrentiels. À l’aide d’une étude de cas portant sur une PME agroalimentaire familiale du secteur fromager auvergnat, nous proposons une analyse en profondeur de ce rôle qui nous parait déterminant. Cette étude est de nature exploratoire et à visée compréhensive. Le mode de recueil des données est multi-angulé. L’hypothèse centrale dans cette recherche est que la création de valeur dans cette entreprise de terroir est déterminée par ses ressources immatérielles (humaines et celles liées au terroir) mobilisées.

Cette étude montre que les atouts essentiels de la PME étudiée sont de nature immatérielle ; tels que le label qu’elle partage avec le groupe stratégique de terroir, les savoir-faire distinctifs (maîtrise des risques sanitaires à travers l’application des normes, des ressources humaines qualifiées) et les relations privilégiées entretenues avec les différents partenaires (notamment les fournisseurs). D’où l’importance en termes de création de valeur des efforts d’investissements dans le capital immatériel (capital humain, image…) et de leur visibilité auprès de différents acteurs économiques et politiques (clients, fournisseurs, collectivités territoriales, interprofessions…). En effet, il nous semble nécessaire que les chercheurs en sciences de gestion participent à l’élaboration de cartographie(s) des ressources immatérielles dans les PME de terroir et plus généralement dans les entreprises industrielles.
Communautés de pratique et capacité d’absorption des connaissances dans un contexte inter-organisationnel
Authors: Amamou Belkassem , Koubaa Salah
Published: June 2014

L’objectif de cet article consiste à mettre en relation les communautés de pratique et l’innovation dans un contexte de relations inter-organisationnelles (RIO) en mettant en exergue le rôle de la capacité d’absorption des connaissances. Autrement dit, nous montrons, dans un modèle de recherche, le processus d’influence positive des communautés de pratique sur l’innovation en considérant la capacité d’absorption comme une variable intermédiaire. Les variables relationnelles de confiance et d’engagement sont considérées comme des facteurs explicatifs de la formation des communautés.

Pour ce faire, nous sommes partis des théories des ressources, des capacités dynamiques ainsi que du constat du manque de ressources et du management de proximité des PME pour faire apparaître un modèle reliant les variables relationnelles (confiance et engagement), les communautés de pratique, le partage des connaissances, la capacité d’absorption et l’innovation. Nous avons testé les hypothèses de recherche sur un échantillon de 110 PME. Les données collectées sont analysées par la méthode des équations structurelles (LISREL pour les analyses confirmatoires et PLS pour les tests d’hypothèses). Les résultats montrent l’existence d’une relation positive entre les variables relationnelles et l’innovation à travers les notions de communautés de pratique. Cette relation est renforcée par le rôle médiateur de la capacité d’absorption des connaissances.
La licence défensive
Authors: Sattin Jean-François
Published: June 2014

À partir de l’étude d’une base de 297 licences internationales collectées auprès des membres de la « Licensing Executive Society », nous montrons que les stratégies de licence défensive sont déployées principalement par de petites entreprises qui n’ont pas les ressources nécessaires pour exclure seules les contrefacteurs potentiels. Par ailleurs, nous mettons en évidence la nature paradoxale de ces stratégies pour le bien-être du breveté. Nous montrons notamment que l’implication du licencié dans la défense des brevets concédés va généralement de pair avec une augmentation des risques contractuels pour le concédant.
Les pratiques de socialisation des petites entreprises françaises
Authors: Bargues Émilie
Published: June 2014

Alors que l’intégration des nouvelles recrues constitue un enjeu particulièrement important pour les petites entreprises, les pratiques de socialisation qu’elles mettent en oeuvre restent mal connues. Cette recherche étudie la diversité des modes de socialisation des petites entreprises françaises en mobilisant le cadre de la théorie des configurations organisationnelles, et plus précisément celle des configurations des petites entreprises (Bentabet, Michun et Trouvé, 1999). Une étude de cas multiple identifie des pratiques de socialisation singulières à chacune de ces configurations. Ces pratiques apparaissent cohérentes entre elles et avec le système des variables caractéristique de la configuration donnée. Ainsi, les modes de socialisation des petites entreprises à configuration « entrepreneuriale » reflètent la volonté de profiter de la présence d’un nouvel entrant pour innover. Celles des petites entreprises à configuration « indépendante traditionnelle » sont orientées par une idéologie de la tradition et prennent la forme d’inculcations normatives. Les pratiques de socialisation des petites entreprises « managériales » renvoient quant à elles à un haut niveau de formalisation, d’organisation, d’outillage gestionnaire et de rationalisation de l’intégration des nouvelles recrues.
Subtropical surface layer salinity budget and the role of mesoscale turbulence
Authors: Busecke Julius , Gordon Arnold L. , Li Zhijin , Bingham Frederick M. , Font Jordi
Published: June 2014

The subtropical North Atlantic exhibits the saltiest surface waters of the open ocean. Eventually that water subducted from the surface and exported toward the Equator, as a subsurface salinity maximum (S‐max) forming the lower limb of the subtropical cell. Climatologically, the winter subtropical surface water, coinciding with the deepest mixed layer of ∼100 m, is saltier and colder than the S‐max. Towed CTD measurements in March/April 2013 (a component of the field program SPURS) within the North Atlantic subtropical surface salinity maximum reveal several relatively fresh, warm anomalies, which deviate strongly from climatological conditions. These features introduce a large amount of freshwater into the subtropical region, exceeding the amount introduced by local rain events. Observed scales and evolution of the features strongly suggest a connection to mesoscale dynamics. This is supported by high‐resolution regional model output, which produces an abundance of features that are similar in scale and structure to those observed. It is hypothesized that turbulent transport in the surface ocean is a crucial process for setting mixed layer characteristics, which spread into S‐max stratum. High variability in the EKE implies a high potential for interannual variability in the resulting S‐max water properties by ocean dynamics in addition to the variability caused by air sea fluxes. This has likely consequences to the meridional transport of heat and freshwater of the subtropical cell in the North Atlantic and to the larger‐scale ocean and climate system.
Effect of low‐permeability layers on spatial patterns of hyporheic exchange and groundwater upwelling
Authors: Gomez‐Velez Jesus D. , Krause Stefan , Wilson John L.
Published: June 2014

Bed form‐induced hyporheic interactions are characterized by a nested system of flow paths that continuously exchange water, solutes, momentum, and energy. At the local scale, sediment heterogeneity plays a key role in the hydrodynamics and potential for biogeochemical transformations within the hyporheic zone. This manuscript explores the role of low‐permeability sedimentary layers on the interplay between bed form‐induced hyporheic exchange and groundwater upwelling. A hydrodynamic conceptualization that sequentially couples fully‐turbulent flow in the water column and Darcian flow in the sediment is used. Low‐permeability layers are characterized by long residence times and solute accumulation. Furthermore, these layers induce hydrodynamic sequestration due to the relocation and, in some cases, emergence of new stagnation zones. Spatial patterns of residence time distributions and flushing intensities indicate that the interface of the low‐permeability layers has the potential to be a hot spot for biogeochemical transformations and flow acceleration near such interface can increase the mobilization capacity for the products of redox chemical and microbial processes. A discussion about the possible implications that hydrodynamic changes have on the biogeochemistry of hyporheic zones is presented; however, further biogeochemical experimentation and modeling are needed to validate these arguments.
New Report Predicts Shortage of Geoscientists in the Workforce
Authors: Wendel JoAnna
Published: June 2014

By the end of the next decade, there may be a shortage of 135,000 geoscientists in the workforce, according to a report issued by the American Geosciences Institute on 29 May. This shortage is predicted despite rising enrollment in the geosciences and rising salaries for students graduating with bachelor's, master's, and doctorate degrees.
Carbon Pollution Guidelines Proposed by EPA
Authors: Showstack Randy
Published: June 2014

A proposal released by the U.S. Environmental Protection Agency (EPA) on 2 June would, for the first time, cut carbon pollution from existing fossil fuel–fired electric‐generating units, which EPA says accounts for about one third of greenhouse gas emissions in the United States.
Tropical Pacific Observing for the Next Decade
Authors: Legler David M. , Hill Katherine
Published: June 2014

More than 60 scientists and program officials from 13 countries met at the Scripps Institution of Oceanography for the Tropical Pacific Observing System (TPOS) 2020 Workshop. The workshop, although motivated in part by the dramatic decline of NOAA's Tropical Atmosphere Ocean (TAO) buoy reporting from mid‐2012 to early 2014 (see http://www.bloomberg.com/news/2014‐03‐07/aging‐el‐nino‐buoys‐getting‐fixed‐as‐weather‐forecasts‐at‐risk.html), evaluated the needs for tropical Pacific observing and initiated efforts to develop a more resilient and integrative observing system for the future.
From Europe to the United States, Rousseau Takes on the Fall Meeting
Authors: McCarter Tricia
Published: June 2014

Denis‐Didier Rousseau smiles shyly when discussing his new role as the chair of AGU's Fall Meeting Program Committee. “I'm not used to giving interviews,” he says. Nonetheless, he becomes very passionate as he begins to talk about his views on transdisciplinary science and its role in AGU meetings, on including more young scientists in planning meetings, and on the importance of virtual meetings. Rousseau, who is currently a visiting professor at Columbia University, sat with Eos to share his excitement about working with AGU.
2014 AGU Mass Media Fellow to Report Science for the Los Angeles Times
Authors: Adams Mary Catherine
Published: June 2014

You could say many geoscientists are in the business of storytelling. They use strata of stone, ice, and other terrestrial ingredients to tell tales of the Earth as it was long ago.
Low‐impact development boosts groundwater recharge
Authors: Schultz Colin
Published: June 2014

In San Francisco, as with other places, climate change is threatening to upset the balance the city has struck with the local hydrology. Precipitation in Northern California has already been increasing in winter and decreasing in summer, and projected changes to the behavior of the El Niño–Southern Oscillation hint at more of the same.
Model describes stratospheric condensation nuclei layer
Authors: Balcerak Ernie
Published: June 2014

Aerosol particles in the stratosphere, including the small particles known as condensation nuclei, affect atmospheric chemistry as well as how the atmosphere absorbs and scatters sunlight, making them a key component in Earth's climate. A new study by Campbell et al. provides the first global three‐dimensional model of the source regions of condensation nuclei in the stratosphere.
Consolidation state of incoming sediments to the Nankai Trough subduction zone: Implications for sediment deformation and properties
Authors: Kitajima Hiroko , Saffer Demian M.
Published: June 2014

The hydromechanical properties of accreted and underthrust sediments are key parameters controlling the mechanics of earthquakes and the development of fluid pressure in subduction zones. We conducted consolidation tests on sediments from the Philippine Sea Plate (PSP) in the Nankai Trough to understand the consolidation state and hydraulic properties of the incoming sediment section before its incorporation into the subduction zone. We used mudstone and sandstone cores sampled from the Integrated Ocean Drilling Program Nankai Trough Seismogenic Zone Experiment at two reference sites (Site C0011 located on a basement low; and Site C0012 located on a basement high). Our experimental results indicate that most of the mudstone samples are normally consolidated or overconsolidated, with overconsolidation ratios (OCR) ranging from 0.89 to 2.52 at Site C0011 and 0.86 to 3.85 at Site C0012. Higher OCR values at Site C0012, at least at shallow depths, are likely caused by erosional unloading. This implies that Site C0011 may serve as a better geotechnical reference site. We also find that mudstones accreted along the frontal thrust are severely overconsolidated relative to coeval mudstones at Site C0011, which likely reflects enhanced consolidation due to increased horizontal tectonic stress. Sandstones in the incoming section on the PSP exhibit 2–3 orders of magnitude higher in situ permeability than the mudstones, and the siliciclastic sandstone we tested maintains a high permeability at stresses up to at least 70 MPa, suggesting that the sandstones may act as important pathways for drainage or pore pressure translation from depths of several kilometers.
Observations of pronounced Greenland ice sheet firn warming and implications for runoff production
Authors: Polashenski Chris , Courville Zoe , Benson Carl , Wagner Anna , Chen Justin , Wong Gifford , Hawley Robert , Hall Dorothy
Published: June 2014

Field measurements of shallow borehole temperatures in firn across the northern Greenland ice sheet are collected during May 2013. Sites first measured in 1952–1955 are revisited, showing long‐term trends in firn temperature. Results indicate a pattern of substantial firn warming (up to +5.7°C) at midlevel elevations (1400–2500 m) and little temperature change at high elevations (>2500 m). We find that latent heat transport into the firn due to meltwater percolation drives the observed warming. Modeling shows that heat is stored at depth for several years, and energy delivered from consecutive melt events accumulates in the firn. The observed warming is likely not yet in equilibrium with recent melt production rates but captures the progression of sites in the percolation facies toward net runoff production.
Nontrivial decay of aftershock density with distance in Southern California
Authors: Moradpour Javad , Hainzl Sebastian , Davidsen Jörn
Published: June 2014

The decay of the aftershock density with distance plays an important role in the discussion of the dominant underlying cause of earthquake triggering. Here, we provide evidence that its form is more complicated than typically assumed and that in particular a transition in the power law decay occurs at length scales comparable to the thickness of the crust. This is supported by an analysis of a very recent high‐resolution catalog for Southern California (SC) and surrogate catalogs generated by the Epidemic‐Type Aftershock Sequence (ETAS) model, which take into account inhomogeneous background activity, short‐term aftershock incompleteness, anisotropic triggering, and variations in the observational magnitude threshold. Our findings indicate specifically that the asymptotic decay in the aftershock density with distance is characterized by an exponent larger than 2, which is much bigger than the observed exponent of approximately 1.35 observed for shorter distances ranging from the main shock rupture length up to a length scale comparable to the thickness of the crust. This has also important consequences for time‐dependent seismic hazard assessment based on the ETAS model.
Nano‐W Dispersed Gamma Radiation Shielding Materials
Authors: Kim Jaewoo , Seo Duckbong , Lee Byung Chul , Seo Young Soo , Miller William H.
Published: June 2014

We present a nano‐W dispersed polymer composite whose gamma attenuation is greatly enhanced. In situ pulverization and simultaneous encapsulation of polyethylene (PE) onto the nano‐W particles was successfully performed by ball milling. Adhesive encapsulation of PE was observed by means of interstitial diffusion of atomic W at the boundary using transmission electron microscope. Prepared nano‐W/PE particles were dispersed into ethylene‐propylene‐based polymer mixture using melt mixing. Attenuation of gammas for the nano‐W composites was enhanced up to ∼75% for Ba‐133 (∼0.3 MeV) compared to the micro‐W composites, while it decreases as the photon energy increases. MCNP simulation also shows similar gamma attenuation behaviors.
Flexible Energy‐Storage Devices: Design Consideration and Recent Progress
Authors: Wang Xianfu , Lu Xihong , Liu Bin , Chen Di , Tong Yexiang , Shen Guozhen
Published: June 2014

Flexible energy‐storage devices are attracting increasing attention as they show unique promising advantages, such as flexibility, shape diversity, light weight, and so on; these properties enable applications in portable, flexible, and even wearable electronic devices, including soft electronic products, roll‐up displays, and wearable devices. Consequently, considerable effort has been made in recent years to fulfill the requirements of future flexible energy‐storage devices, and much progress has been witnessed. This review describes the most recent advances in flexible energy‐storage devices, including flexible lithium‐ion batteries and flexible supercapacitors. The latest successful examples in flexible lithium‐ion batteries and their technological innovations and challenges are reviewed first. This is followed by a detailed overview of the recent progress in flexible supercapacitors based on carbon materials and a number of composites and flexible micro‐supercapacitors. Some of the latest achievements regarding interesting integrated energy‐storage systems are also reviewed. Further research direction is also proposed to surpass existing technological bottle‐necks and realize idealized flexible energy‐storage devices.