1,124 research outputs found
Coastal wetlands: A Synthesis
No full textThis book and this synthesis address the pressing need for better management of coastal wetlands worldwide because these wetlands are disappearing at an alarming rate; in some countries the loss is 70%–80% in the last 50 years. Managing requires understanding. Although our understanding of the functioning of coastal wetland ecosystems has grown rapidly over the past decade, still much remains to be learned and understood. We have gained insight into the roles of geomorphic processes, hydrologic dynamics, biotic feedback, and disturbance agents in creating and molding a variety of coastal wetland ecosystems across climatic gradients. The variety is expressed not so much in the more obvious differences in vegetation cover, but rather how physical processes both facilitate and constrain a diversity of plant and animal communities. At one level, coastal wetlands are the product of tidal forces and freshwater inputs at the margin of continents. At another level, the plants control the water currents in the tidal creeks draining the wetlands by generating a tidal current asymmetry that controls sediment transport and results in a deep tidal creek surrounded by shallow vegetated wetlands. The vegetation also influences the physics of water and sediment through several other processes including biofilms, bioturbation of sediments, the buffeting of currents and waves, organic enrichment of sediments, and the closing of nutrient cycles. Few ecosystems provide us with so many clear examples of such feedback controls. What we do understand about the structure and functioning of coastal wetlands should provide the theoretical underpinnings for effective management in protecting them for their many contributions to ecosystem goods and services. What we do not understand should compel us to focus our attention and energies toward seeking optimal solutions to some of the most perplexing and urgent problems facing natural resource management.Fil: Hopkinson, Charles S.. University of Georgia; Estados UnidosFil: Wolanski, Eric. James Cook University; Australia. Australian Institute of Marine Science; AustraliaFil: Cahoon, Donald R.. Patuxent Wildlife Research Center; Estados UnidosFil: Perillo, Gerardo Miguel E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Brinson, Mark M.. No especifíca;Fil: Hopkinson, Charles S.. University of Georgia; Estados Unido
In Search of Protection: Unaccompanied Minors in Italy
No full textThis paper examines the issue of unaccompanied minors arriving in Italy and how Italy has responded to their need for protection. It contains ¡ve complementary sections. Section 1, authored by Pietro Demurtas, provides a statistical overview of unaccompanied minors in Italy between 2014 and 2017. In particular, it discusses unaccompanied minors who request political asylum, those in government reception facilities who do not, and those who have left reception centers without seeking asylum and have become "untraceable." The second section by Mattia Vitiello addresses why unaccompanied minors leave their countries of origin and how they transit to Italy and elsewhere. This section highlights the role of families in the decision to migrate and the migration process. It distinguishes unaccompanied minors who largely seek to "escape from" particular conditions from other migrants who are in search of a better life for themselves and their families. The third section by Marco Accorinti covers Italian reception policies and policymaking challenges, with a particular focus on implementation of Italy's System for the Protection of Asylum Seekers and Refugees. The section argues for reception procedures and interventions that are tailored to the particular vulnerabilities and needs of unaccompanied minors. Section 4, authored by Aldo Skoda, c.s., offers a psychosocial analysis of the phenomenon of unaccompanied child migration. It describes strategies to build the competencies, sense of agency, and resilience of unaccompanied minors. The final section, authored by Carola Perillo, details the demands and requirements of acting in the "best interests" of unaccompanied minors. It ends by setting forth minimum principles of protection for unaccompanied minors, which should inform both the Global Compact on Migration and the Global Compact on Refugees
Su di un caso di morbo di Paget a prevalente localizzazione mandibolare complicato da tumore gigantocellulare
No full textEffect of varus/valgus malalignment on bone strains in the proximal tibia after TKR: an explicit finite element study
No full textMalalignment is the main cause of tibial component loosening. Implants that migrate
rapidly in the first two post-operative years are likely to present aseptic loosening. It has
been suggested that cancellous bone stresses can be correlated with tibial component
migration. A recent study has shown that patient-specific finite element (FE) models have
the power to predict the short-term behavior of tibial trays. The stresses generated within
the implanted tibia are dependent on the kinematics of the joint; however, previous
studies have ignored the kinematics and only applied static loads. Using explicit FE, it is
possible to simultaneously predict the kinematics and stresses during a gait cycle. The
aim of this study was to examine the cancellous bone strains during the stance phase of
the gait cycle, for varying degrees of varus/valgus eccentric loading using explicit FE. A
patient-specific model of a proximal tibia was created from CT scan images, including
heterogeneous bone properties. The proximal tibia was implanted with a commercial
total knee replacement (TKR) model. The stance phase of gait was simulated and the
applied loads and boundary conditions were based on those used for the Stanmore knee
simulator. Eccentric loading was simulated. As well as examining the tibial bone strains
(minimum and maximum principal strain), the kinematics of the bone-implant construct
are also reported. The maximum anterior–posterior displacements and internal–external
rotations were produced by the model with 20 mm offset. The peak minimum and maximum
principal strain values increased as the load was shifted laterally, reaching a
maximum magnitude for ?20 mm offset. This suggests that when in varus, the load
transferred to the bone is shifted medially, and as the bone supporting this load is stiffer,
the resulting peak bone strains are lower than when the load is shifted laterally (valgus).
For this particular patient, the TKR design analyzed produced the highest cancellous
bone strains when in valgus. This study has provided an insight in the variations produced
in bone strain distribution when the axial load is applied eccentrically. To the
authors’ knowledge, this is the first time that the bone strain distribution of a proximal
implanted tibia has been examined, also accounting for the kinematics of the tibio–
femoral joint as part of the simulation. This approach gives greater insight into the
overall performance of TKR
Secure Selections on Encrypted Multi-writer Streams
No full textPerforming searches over encrypted data is a very current and active area. Several efficient solutions have been provided for the single-writer scenario in which all sensitive data originate with one party (the Data Owner) that encrypts and uploads the data to a public repository. Subsequently, the Data Owner accesses the encrypted data through a Query Processor, which has direct access to the public encrypted repository. Motivated by the recent trend in pervasive data collection, we depart from this model and consider a multi-writer scenario in which the data originate with several and mutually untrusted parties, the Data Sources. In this new scenario, the Data Owner provides public parameters so that each Data Source can add encrypted items to the public encrypted stream; moreover, the Data Owner keeps some related secret information needed to generate tokensso that different Query Sources can decrypt different subsets of the encrypted stream, as specified by corresponding access policies.We propose security model for this problem that we call Secure Selective Stream(SSS) and give a secure construction for it based on hard problems in Pairing-Based Cryptography. The cryptographic core of our construction is a new primitive, Amortized Orthogonality Encryption, that is crucial for the efficiency of the proposed implementation for SSS
Coastal Wetlands: A Synthesis
No full textWhat are coastal wetland ecosystems, what are their limits of distribution, and where dothey exist in the overall coastal landscape? There are several general definitions for wetlands,but the Ramsar definition is likely the most broadly encompassing (http://www.ramsar.org/), whereas others are more focused definitions tailored to country-specific protectionand management policies (Mitsch and Gosselink, 2006). We offer a very general approachrather than a precise definition: coastal wetlands are ecosystems that are found within anelevation gradient that ranges between subtidal depths where light penetrates to supportphotosynthesis of benthic plants to the landward edge where the sea passes its hydrologicinfluence to groundwater and atmospheric processes. At the seaward margin, biofilms,benthic algae, and seagrasses are representative biotic components. At the landward margin,vegetation boundaries range from those located on groundwater seeps or fens in humidclimates to relatively barren salt flats in arid climates.Fil: Hopkinson, Charles S.. University of Georgia; Estados UnidosFil: Wolanski, Eric. James Cook University; Australia. Australian Institute of Marine Science; AustraliaFil: Brinson, Mark M.. Brinson East Carolina University; Estados UnidosFil: Cahoon, Donald R.. United States Geological Survey; Estados UnidosFil: Perillo, Gerardo Miguel E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur. Departamento de Geología; Argentin
A new langmuir-schaefer-based method developed for catalytic studies of acetylcholinesterase in planar fiolms of erythrocyte membranes
No full textFil: Felsztyna, I. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina.Fil: Felsztyna, I. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Química. Cátedra de Química Biológica; Argentina.Fil: Perillo, M. A. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina.Fil: Perillo, M. A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Química. Cátedra de Química Biológica; Argentina.Fil: Clop, E. M. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina.Fil: Clop, E. M. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Química. Cátedra de Química Biológica; Argentina.Previously we reported that the catalytic activity of bovine erythrocyte acetylcholinesterase (BEA) located in Langmuir-Blodgett films (LB) of bovine erythrocyte membranes (BEM), LBBEA, depended on the curvature and packing of the molecular environment. Moreover, the specific activity of LBBEA was much lower than that of BEA in suspensions of BEM vesicles (SBEA). So, the present work was aimed at maximizing the specific activity of BEA recovered from the transfer of a Langmuir film (LF) from the air-aqueous interface to alkylated solid surfaces and improving the precision of the enzymatic assays.Fil: Felsztyna, I. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina.Fil: Felsztyna, I. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Química. Cátedra de Química Biológica; Argentina.Fil: Perillo, M. A. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina.Fil: Perillo, M. A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Química. Cátedra de Química Biológica; Argentina.Fil: Clop, E. M. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina.Fil: Clop, E. M. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Química. Cátedra de Química Biológica; Argentina.Biofísic
A combined RSA and FE study of the implanted proximal tibia: correlation of the post-operative mechanical environment with implant migration
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