Measuring consistency in TTL-based caches

We propose a general modeling framework to evaluate the performance of cache consistency algorithms. In addition to the usual hit rate, we introduce the hit^* rate as a consistency measure, which captures the fraction of non-stale downloads from the cache. We apply these ideas to the analysis of the fixed TTL consistency algorithm in the presence of network delays. The hit and hit^* rates are evaluated when requests and updates are modeled by renewal processes. Classical results on the renewal function lead to various bounds.     

Advection‐Based Function Matching on Surfaces

A tangent vector field on a surface is the generator of a smooth family of maps from the surface to itself, known as the flow. Given a scalar function on the surface, it can be transported, or advected, by composing it with a vector field's flow. Such transport is exhibited by many physical phenomena, e.g., in fluid dynamics. In this paper, we are interested in the inverse problem: given source and target functions, compute a vector field whose flow advects the source to the target. We propose a method for addressing this problem, by minimizing an energy given by the advection constraint together with a regularizing term for the vector field. Our approach is inspired by a similar method in computational anatomy, known as LDDMM, yet leverages the recent framework of functional vector fields for discretizing the advection and the flow as operators on scalar functions. The latter allows us to efficiently generalize LDDMM to curved surfaces, without explicitly computing the flow lines of the vector field we are optimizing for. We show two approaches for the solution: using linear advection with multiple vector fields, and using non‐linear advection with a single vector field. We additionally derive an approximated gradient of the corresponding energy, which is based on a novel vector field transport operator. Finally, we demonstrate applications of our machinery to intrinsic symmetry analysis, function interpolation and map improvement.     

Effect of Fe-doping on Magnetocaloric Properties of AMn1?x Fe x O3 Compounds (0≤x≤0.2)

We have investigated the effect of iron substitution on the magnetocaloric properties of manganites with La_0.75Ca_0.08Sr_0.17Mn_1?x Fe _x O₃ (x=0, 0.075, 0.15, 0.175, and 0.2) nominal composition. The magnetocaloric effect (MCE) was estimated, in terms of isothermal magnetic entropy change (???S _M ), using the M(T,?? ₀ H) data and employing the thermodynamic Maxwell equation. The large magnetic entropy in AMn_1?x Fe _x O₃ is attributed to the field-induced suppression of short-range charge-orbital ordering and antiferromagnetic fluctuations present above T _C . The increase of the Fe concentration x is accompanied by a decrease of (???S _M ), from 5.205 to 0.95?J/kg?K for x=0 and 0.20, respectively, with ?? ₀ H=5?T. For all samples, we find quite large values of (???S _M ), which are very close to that provided for Gd, the prototypical magnetocaloric material.     

An Operator Approach to Tangent Vector Field Processing

In this paper, we introduce a novel coordinate‐free method for manipulating and analyzing vector fields on discrete surfaces. Unlike the commonly used representations of a vector field as an assignment of vectors to the faces of the mesh, or as real values on edges, we argue that vector fields can also be naturally viewed as operators whose domain and range are functions defined on the mesh. Although this point of view is common in differential geometry it has so far not been adopted in geometry processing applications. We recall the theoretical properties of vector fields represented as operators, and show that composition of vector fields with other functional operators is natural in this setup. This leads to the characterization of vector field properties through commutativity with other operators such as the Laplace‐Beltrami and symmetry operators, as well as to a straight‐forward definition of differential properties such as the Lie derivative. Finally, we demonstrate a range of applications, such as Killing vector field design, symmetric vector field estimation and joint design on multiple surfaces.     

A method for the remote sensing identification of uncontrolled landfills: formulation and validation

The identification of uncontrolled landfills is a central environmental problem in all developed and developing countries, where several illegal waste deposits exist as a result of rapid industrial growth over the past century. Remote sensing can potentially provide crucial information for the identification of contaminated sites, but surprisingly there is a marked lack of rigorously validated approaches. In this paper we introduce and validate a method that uses remotely sensed information and a geographic information system (GIS) to identify unknown landfills over large areas. The method is applied to a study area located in NE Italy (part of the Venice lagoon watershed) using IKONOS satellite data. Soil contamination effects on the radiometric properties of vegetation, calibrated using spectral signatures of stressed vegetation from known illegal landfill sites, were used to define numerous candidate sites that are most likely to host waste materials. Distributed geographical information, such as the position of the road network, the population density, and historical aerial photographs, have then been used to select the most likely contaminated sites among the candidates identified through remote sensing. The importance of the integration of GIS and remote sensing is highlighted and represents a key instrument for environmental management and for the spatially distributed characterization of possible uncontrolled landfill sites.     

The influence of the in-plane warping on the behavior of thin-walled beams

The paper presents a theoretical study of the importance of the in-plane deformation on the structural behavior of thin-walled isotropic and composite beams which are subjected to bending and torsional moments. To separate the effects of the out-of-plane warping and the in-plane warping, the overall solution methodology is based on a generic combination of two complementary “inner” and “outer” solutions. The inner model is based on numerical optimization tools which are employed to determine the in-plane deformation that will ensure a stationary (minimum) state of the total potential energy. The outer model performs global solution for cross-sections that are rigid in their own plane but includes the out-of-plane warping. The overall solution is capable of determining the influence of the in-plane warping on any existing approximate numerical scheme that do not include this deformation component. The results correlate well with known analytic solutions for isotropic tubes under pure bending. A parametric study of the relative importance of the in-plane warping as a function of the geometry and the loading parameters in rectangular thin-walled isotropic and composite beams is also presented along with some buckling considerations.     

Attachment theory and rections to others' needs: Evidence that activiation of the sense of attachment security promotes empathic responses.

Five studies examined the effects of chronic and contextual activation of attachment security on reactions to others' needs. The sense of attachment security was contextually primed by asking participants to recollect personal memories, read a story, or look at a picture of supportive others or by subliminally exposing them to proximity-related words. This condition was compared against the priming of neutral themes, positive affect, or attachment-insecurity schemas. Then reports of empathy and personal distress or the accessibility of empathy and personal-distress memories were assessed. Attachment-security priming strengthened empathic reactions and inhibited personal distress. Self-reports of attachment anxiety and avoidance were inversely related to empathy, and attachment anxiety was positively related to personal distress. The discussion emphasizes the relevance of attachment theory for explaining reactions to others' needs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Topology,in Model Membranes,of the Core Peptide Derived from the T‐Cell Receptor Transmembrane Domain

The T‐cell receptor–CD3 complex (TCR–CD3) serves a critical role in protecting organisms from infectious agents. The TCR is a heterodimer composed of α‐ and β‐chains, which are responsible for antigen recognition. Within the transmembrane domain of the α‐subunit, a region has been identified to be crucial for the assembly and function of the TCR. This region, termed core peptide (CP), consists of nine amino acids (GLRILLLKV), two of which are charged (lysine and arginine) and are crucial for the interaction with CD3. Earlier studies have shown that a synthetic peptide corresponding to the CP sequence can suppress the immune response in animal models of T‐cell‐mediated inflammation, by disrupting proper assembly of the TCR. As a step towards the understanding of the source of the CP activity, we focused on CP in egg phosphatidylcholine/cholesterol (9:1, mol/mol) model membranes and determined its secondary structure, oligomerization state, and orientation with respect to the membrane. To achieve this goal, 15‐residue segments of TCRα, containing the CP, were synthesized and spin‐labeled at different locations with a nitroxide derivative. Electron spin‐echo envelope modulation spectroscopy was used to probe the position and orientation of the peptides within the membrane, and double electron–electron resonance measurements were used to probe its conformation and oligomerization state. We found that the peptide is predominantly helical in a membrane environment and tends to form oligomers (mostly dimers) that are parallel to the membrane plane.     

Comparison of the bactericidal action of amikacin, netilmicin and tobramycin in free and liposomal formulation against Pseudomonas aeruginosa

Glycoprotein Ibalpha (GP Ibalpha; CD 42b; hereafter GPIBA) is a component of the cell surface receptor for the von Willebrand factor (vWf) on platelets. Immunizations against various platelet surface antigens play a major role in neonatal alloimmune thrombocytopenia and in post-transfusion purpura. Only one antigenic polymorphism in GPIBA has thus far been established: the HPA-2 (Ko) alloantigen system. To screen other polymorphisms in GPIBA systematically, we analyzed the whole coding sequence of the GPIBA gene in 50 Finnish blood donors using the single-strand conformation polymorphism method. In addition to the known polymorphisms, we detected three others. Sequencing of the gene segments carrying the new polymorphisms revealed that none of them changed the predicted amino acid sequence. Polymorphism designated RS was located five base pairs upstream from the initiation codon at position 3064 and had the gene frequency of 16% for R and 84% for S, respectively, in the Finnish population, and it was detectable by the restriction enzyme Hae III. The EF polymorphism was at position 3842 (Asn242) and the gene frequencies were 97% for E and 3% for F. The KL polymorphism was at position 4142 (Arg342) and the gene frequencies were 98% for K and 2% for L. The five polymorphic positions in GPIBA formed altogether six different alleles of the gene. The data suggest that there are only a few variable amino acids in GPIBA.