Bringing tabletop technologies to kindergarten children

Taking computer technology away from the desktop and into a more physical, manipulative space, is known that provide many benefits and is generally considered to result in a system that is easier to learn and more natural to use. This paper describes a design solution that allows kindergarten children to take the benefits of the new pedagogical possibilities that tangible interaction and tabletop technologies offer for manipulative learning. After analysis of children's cognitive and psychomotor skills, we have designed and tuned a prototype game that is suitable for children aged 3 to 4 years old. Our prototype uniquely combines low cost tangible interaction and tabletop technology with tutored learning. The design has been based on the observation of children using the technology, letting them freely play with the application during three play sessions. These observational sessions informed the design decisions for the game whilst also confirming the children's enjoyment of the prototype

Introduction: Developing Strategies for Stability and a Sustainable Shared Development in Euro-Mediterranean Migrations

This special issue on migration offers a collection of contributions from prominent scholars, academics, and researchers from Europe, Africa, and the United States who provide a unique multilevel and prismatic analysis of this fundamental social phenomenon

Strategies for Stability and Sustainability in Euro-Mediterranean Migrations

In this article, the author provides a wide and vivid picture of the several dimensions of migration flows in the current global scenario and, in particular, in the Mediterranean. She proposes new interpretations of this complex phenomenon, analyzing its multiple aspects and characteristics and the push factors and policies and responses of the countries of origin, transit, and destination. She suggests new approaches and strategies to deal with the issue of migration, urging the EU member states and EU institutions to develop management policies for stability and sustainability that are welcoming and that respect human rights

Viscoelasticity and Stokes-Einstein relation in repulsive and attractive colloidal glasses

We report a numerical investigation of the visco-elastic behavior in models for steric repulsive and short-range attractive colloidal suspensions, along different paths in the attraction-strength vs packing fraction plane. More specifically, we study the behavior of the viscosity (and its frequency dependence) on approaching the repulsive glass, the attractive glass and in the re-entrant region where viscosity shows a non monotonic behavior on increasing attraction strength. On approaching the glass lines, the increase of the viscosity is consistent with a power-law divergence with the same exponent and critical packing fraction previously obtained for the divergence of the density fluctuations. Based on mode-coupling calculations, we associate the increase of the viscosity with specific contributions from different length scales. We also show that the results are independent on the microscopic dynamics by comparing newtonian and brownian simulations for the same model. Finally we evaluate the Stokes-Einstein relation approaching both glass transitions, finding a clear breakdown which is particularly strong for the case of the attractive glass.Comment: 12 pages; sent to J. Chem. Phy

Modulation of PKM alternative splicing by PTBP1 promotes gemcitabine resistance in pancreatic cancer cells

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive and incurable disease. Poor prognosis is due to multiple reasons, including acquisition of resistance to gemcitabine, the first-line chemotherapeutic approach. Thus, there is a strong need for novel therapies, targeting more directly the molecular aberrations of this disease. We found that chronic exposure of PDAC cells to gemcitabine selected a subpopulation of cells that are drug-resistant (DR-PDAC cells). Importantly, alternative splicing (AS) of the pyruvate kinase gene (PKM) was differentially modulated in DR-PDAC cells, resulting in promotion of the cancer-related PKM2 isoform, whose high expression also correlated with shorter recurrence-free survival in PDAC patients. Switching PKM splicing by antisense oligonucleotides to favor the alternative PKM1 variant rescued sensitivity of DR-PDAC cells to gemcitabine and cisplatin, suggesting that PKM2 expression is required to withstand drug-induced genotoxic stress. Mechanistically, upregulation of the polypyrimidine-tract binding protein (PTBP1), a key modulator of PKM splicing, correlated with PKM2 expression in DR-PDAC cell lines. PTBP1 was recruited more efficiently to PKM pre-mRNA in DR- than in parental PDAC cells. Accordingly, knockdown of PTBP1 in DR-PDAC cells reduced its recruitment to the PKM pre-mRNA, promoted splicing of the PKM1 variant and abolished drug resistance. Thus, chronic exposure to gemcitabine leads to upregulation of PTBP1 and modulation of PKM AS in PDAC cells, conferring resistance to the drug. These findings point to PKM2 and PTBP1 as new potential therapeutic targets to improve response of PDAC to chemotherapy.Oncogene advance online publication, 3 August 2015; doi:10.1038/onc.2015.270

The influence of light attenuation on the biogeomorphology of a marine karst cave: a case study of Puerto Princesa Underground River, Palawan, the Philippines

Karst caves are unique biogeomorphological systems. Cave walls offer habitat for microorganisms which in-turn have a geomorphological role via their involvement in rock weathering, erosion and mineralisation. The attenuation of light with distance into caves is known to affect ecology, but the implications of this for biogeomorphological processes and forms have seldom been examined. Here we describe a semi-quantitative microscopy study comparing the extent, structure, and thickness of biocover and depth of endolithic penetration for samples of rock from the Puerto Princesa Underground River system in Palawan, the Philippines, which is a natural UNESCO World Heritage Site. Organic growth at the entrance of the cave was abundant (100% occurrence) and complex, dominated by phototrophic organisms (green microalgae, diatoms, cyanobacteria, mosses and lichens). Thickness of this layer was 0.28 ± 0.18 mm with active endolith penetration into the limestone (mean depth = 0.13 ± 0.03 mm). In contrast, phototrophs were rare 50 m into the cave and biofilm cover was significantly thinner (0.01 ± 0.01 mm, p < 0.000) and spatially patchy (33% occurrence). Endolithic penetration here was also shallower (< 0.01 mm, p < 0.000) and non-uniform. Biofilm was found 250 m into the cave, but with a complete absence of phototrophs and no evidence of endolithic bioerosion. We attribute these findings to light-induced stress gradients, showing that the influence of light on phototroph abundance has knock-on consequences for the development of limestone morphological features. In marine caves this includes notches, which were most well-developed at the sheltered cave entrance of our study site, and for which variability in formation rates between locations is currently poorly understood

Crystallization Mechanism of Hard Sphere Glasses

In supercooled liquids, vitrification generally suppresses crystallization. Yet some glasses can still crystallize despite the arrest of diffusive motion. This ill-understood process may limit the stability of glasses, but its microscopic mechanism is not yet known. Here we present extensive computer simulations addressing the crystallization of monodisperse hard-sphere glasses at constant volume (as in a colloid experiment). Multiple crystalline patches appear without particles having to diffuse more than one diameter. As these patches grow, the mobility in neighbouring areas is enhanced, creating dynamic heterogeneity with positive feedback. The future crystallization pattern cannot be predicted from the coordinates alone: crystallization proceeds by a sequence of stochastic micro-nucleation events, correlated in space by emergent dynamic heterogeneity.Comment: 4 pages 4 figures Accepted for publication in Phys. Rev. Lett., April 201