Facts, trends and challenges in modern software development

The IT industry is not new to change and evolution, however, we are now in an era of two fundamental waves of IT changes. First, the post-PC era, where mobile devices and tablet-like devices are giving end-users the ability to consume information when they want it and where they want it. Second, the post-server era where companies no longer need to neither buy nor provision servers in their own data centres but instead rent the compute resources as needed. This twin change has direct consequences to how end-users consume software, how that software is produced, and how it is delivered.info:eu-repo/semantics/publishedVersio

The Programmable Web: Agile, Social, and Grassroots Computing

Web services, the semantic Web, and Web 2.0 are three somewhat separate movements trying to make the Web a programmable substrate. While each has achieved some level of success on their own right, it is becoming apparent that the grassroots approach of the Web 2.0 is gaining greater success than the other two. In this paper we analyze each movement, briefly describing its main traits, and outlining its primary assumptions. We then frame the common problem of achieving a programmable Web within the context of distributed computing and software engineering and then attempt to show why Web 2.0 is closest to give a pragmatic solution to the problem and will therefore likely continue to have the most success while the other two only have cursory contributions

Molecular Density Functional Theory of Water describing Hydrophobicity at Short and Long Length Scales

We present an extension of our recently introduced molecular density functional theory of water [G. Jeanmairet et al., J. Phys. Chem. Lett. 4, 619, 2013] to the solvation of hydrophobic solutes of various sizes, going from angstroms to nanometers. The theory is based on the quadratic expansion of the excess free energy in terms of two classical density fields, the particle density and the multipolar polarization density. Its implementation requires as input a molecular model of water and three measurable bulk properties, namely the structure factor and the k-dependent longitudinal and transverse dielectric susceptibilities. The fine three-dimensional water structure around small hydrophobic molecules is found to be well reproduced. In contrast the computed solvation free-energies appear overestimated and do not exhibit the correct qualitative behavior when the hydrophobic solute is grown in size. These shortcomings are corrected, in the spirit of the Lum-Chandler-Weeks theory, by complementing the functional with a truncated hard-sphere functional acting beyond quadratic order in density. It makes the resulting functional compatible with the Van-der-Waals theory of liquid-vapor coexistence at long range. Compared to available molecular simulations, the approach yields reasonable solvation structure and free energy of hard or soft spheres of increasing size, with a correct qualitative transition from a volume-driven to a surface-driven regime at the nanometer scale.Comment: 24 pages, 8 figure

IBM Altocumulus: A Cross-Cloud Middleware and Platform

Cloud computing has become the new face of computing and promises to offer virtually unlimited, cheap, readily available, utility type computing resources. Many vendors have entered this market with different offerings ranging from infrastructure-as-a-service such as Amazon, to fully functional platform services such as Google App Engine. However, as a result of this heterogeneity, deploying applications to a cloud and managing them needs to be done using vendor specific methods. This lock in is seen as a major hurdle in adopting cloud technologies to the enterprise. IBM Altocumulus, the cloud middleware platform from IBM Almaden Services Research, aims to solve this very issue of managing applications across multiple clouds. It provides a uniform, service oriented interface to deploy and manage applications in various clouds and also provides facilities to migrate instances across clouds using repeatable best practice patterns. In this demonstration we will present the latest version of the IBM Altocumulus platform and also reveal some of the latest additions on scaling and the ability to perform map-reduce type computations

Fatigue and fracture of bulk metallic glasses : role of free volume

Deformation of metallic glasses requires the existence of free volume to allow atomic movement under mechanical loading. Accordingly, the present research seeks to understand how free volume variations in alloys of identical compositions affect the fatigue and fracture behavior. By annealing below the glass transition temperature, the free volume of a Zr-based bulk metallic glass was varied via structural relaxation. Differential scanning calorimetry was used to quantify enthalpy differences between the relaxed and as-cast materials which are then related to free volume differences. Although structural relaxation showed a pronounced effect in reducing the fracture toughness, a reduction in free volume increases the fatigue strength of the bulk amorphous alloy. Mechanistically, the fatigue properties associated with a free volume variation differ significantly with respect to crack initiation. Surprisingly, the fatigue crack-growth behavior was found to be relatively insensitive to bulk free volume differences. Depth-profiled Doppler broadening spectroscopy (DBS) was utilized to perform local depth profiling of fatigue fracture surfaces to characterize local free volume differences. It’s demonstrated that the intense deformation near a fatigue crack tip result in a local increase in free volume, which in turn determines the local flow properties. The effect of residual stresses on the fatigue and fracture behavior was also investigated. The superimposition of compressive stresses induced by thermal tempering during processing was found to retard fatigue crack propagation and to improve the fracture toughness

CXCR4 identifies transitional bone marrow premonocytes that replenish the mature monocyte pool for peripheral responses

It is well established that Ly6Chi monocytes develop from common monocyte progenitors (cMoPs) and reside in the bone marrow (BM) until they are mobilized into the circulation. In our study, we found that BM Ly6Chi monocytes are not a homogenous population, as current data would suggest. Using computational analysis approaches to interpret multidimensional datasets, we demonstrate that BM Ly6Chi monocytes consist of two distinct subpopulations (CXCR4hi and CXCR4lo subpopulations) in both mice and humans. Transcriptome studies and in vivo assays revealed functional differences between the two subpopulations. Notably, the CXCR4hi subset proliferates and is immobilized in the BM for the replenishment of functionally mature CXCR4lo monocytes. We propose that the CXCR4hi subset represents a transitional premonocyte population, and that this sequential step of maturation from cMoPs serves to maintain a stable pool of BM monocytes. Additionally, reduced CXCR4 expression on monocytes, upon their exit into the circulation, does not reflect its diminished role in monocyte biology. Specifically, CXCR4 regulates monocyte peripheral cellular activities by governing their circadian oscillations and pulmonary margination, which contributes toward lung injury and sepsis mortality. Together, our study demonstrates the multifaceted role of CXCR4 in defining BM monocyte heterogeneity and in regulating their function in peripheral tissues

A microfluidic technique for generating monodisperse submicron-sized drops

International audienceWe present a route for producing monodisperse micro and nanodrops that is based on a liquid-gas phase transition occurring within a microfluidic device. A gas which is soluble in water is mixed with an insoluble one and injected into an aqueous surfactant solution, using a microfluidic device that produces monodisperse bubbles. As the soluble gas diffuses out of the bubbles, they shrink and the remaining insoluble gas condenses into drops. Their radius can be tuned over a wide range by changing the initial gas mixing ratio