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About 100 km east of Rome, in the central Apennine Mountains, a critically endangered population of ∼50 brown bears live in complete isolation. Mating outside this population is prevented by several 100 km of bear-free territories. We exploited this natural experiment to better understand the gene and genomic consequences of surviving at extremely small population size. We found that brown bear populations in Europe lost connectivity since Neolithic times, when farming communities expanded and forest burning was used for land clearance. In central Italy, this resulted in a 40-fold population decline. The overall genomic impact of this decline included the complete loss of variation in the mitochondrial genome and along long stretches of the nuclear genome. Several private and deleterious amino acid changes were fixed by random drift; predicted effects include energy deficit, muscle weakness, anomalies in cranial and skeletal development, and reduced aggressiveness. Despite this extreme loss of diversity, Apennine bear genomes show nonrandom peaks of high variation, possibly maintained by balancing selection, at genomic regions significantly enriched for genes associated with immune and olfactory systems. Challenging the paradigm of increased extinction risk in small populations, we suggest that random fixation of deleterious alleles (i) can be an important driver of divergence in isolation, (ii) can be tolerated when balancing selection prevents random loss of variation at important genes, and (iii) is followed by or results directly in favorable behavioral changes., Financial support for the collection of the samples was provided by Vodafone Greece and the Vodafone Group Foundation. Fondo Ateneo Ricerca (FAR) grants from the University of Ferrara supported the study. P.M.D. was funded by Agence Nationale de la Recherche Demochips Grant ANR-12-BSV7-0012.

Defining reliable demographic models is essential to understand the threats of ongoing environmental change. Yet, in the most remote and threatened areas, models are often based on the survey of a single population, assuming stationarity and independence in population responses. This is the case for the Emperor penguin Aptenodytes forsteri, a flagship Antarctic species that may be at high risk continent-wide before 2100. Here, using genome-wide data from the whole Antarctic continent, we reveal that this top-predator is organized as one single global population with a shared demography since the late Quaternary. We refute the view of the local population as a relevant demographic unit, and highlight that (i) robust extinction risk estimations are only possible by including dispersal rates and (ii) colony-scaled population size is rather indicative of local stochastic events, whereas the species' response to global environmental change is likely to follow a shared evolutionary trajectory., Delimiting populations is crucial for conserving threatened species. Using genome-wide data from the whole of Antarctica, Cristofari et al. show that Emperor penguins are organised into a single global population that have shared demography since the late Quarternary.

A coupled 2D-3D finite element model developed with COMSOL Multiphysics software platform is proposed to design novel acoustic particle velocity sensors. The device consists of four silicided polysilicon wires arranged in a Wheatstone full-bridge configuration. Each wire has been divided into three segments placed over suspended silicon dioxide membranes. The dependence of the device sensitivity and frequency response on geometric dimensions has been investigated.

The crystal and molecular structures of Ph 3 SnCHClCH 2 SC 6 H 3 NO 2 -2-Y-4 (II, Y  Me) and Ph 3 SnCH(SCN)CH 2 SC 6 H 4 NO 2 - o (III) have been determined. Compounds II and Ill are adducts of Ph 3 SnCHCH 2 and the appropriate sulphenyl chloride and thiocyanate. Both compounds are monomeric and contain slightly distorted tetrahedral tin atoms. The intra-molecular SnS(R) distances in II (Y  Me) and III are 3.67 and 3.58 A, respectively. The solid state conformations are staggered and have dihedral angles SnCCS of 56.6 and 57.4° in II (Y  Me) and III, respectively, and ClCCS in II and SCCS in III 176.0° and 174.1°, respectively. From 3 J (HH) and 3 J ( 119 Sn 1 H) values, the solid state conformation of II (Y  Me) is calculated to be populated in solution for approximately 1/3rd of the time at 25°C.

The differential radial distribution functions of a sample of amorphous (atactic) poly(propylene) and of an isotactic one were compared, showing the absence, in the former sample, of interatomic correlations beyond 8 A (1 A = 0,1 nm). The influence of the length of atactic and isotactic chain segments on the calculated X-ray interference functions was investigated. A model based on the arrangement of atactic chains in close-packed spheres fits well the experimental X-ray diffraction pattern of the amorphous sample.