Critical behavior of the specific heat in glass formers

We show numeric evidence that, at low enough temperatures, the potential energy density of a glass-forming liquid fluctuates over length scales much larger than the interaction range. We focus on the behavior of translationally invariant quantities. The growing correlation length is unveiled by studying the finite-size effects. In the thermodynamic limit, the specific heat and the relaxation time diverge as a power law. Both features point towards the existence of a critical point in the metastable supercooled liquid phase.

Finite size effects in the specific heat of glass-formers

We report clear finite size effects in the specific heat and in the relaxation times of a model glass former at temperatures considerably smaller than the Mode Coupling transition. A crucial ingredient to reach this result is a new Monte Carlo algorithm which allows us to reduce the relaxation time by two order of magnitudes. These effects signal the existence of a large correlation length in static quantities.

The making and unmaking of heritage

Heritage is defined by history which is by nature multi layered. The passage of time and the perspectives it affords, enables and even necessitates constant reexamination and reinterpretation of history. What effect do changes in historical perspective then have upon the definition of heritage which relies on an understanding of its history? The present paper attempts to engage with the notion of heritage, criteria of its definition, and the mutable nature of such designations with specific reference to architectural constructions and historical cities that enjoy or have enjoyed in the past the status of a ‘World Heritage Site’. Examples such as the Louvre museum in Paris or the King’s Cross station in London make an interesting study as they not only allow insight into the past but reflect the changes and adaptation over a period of time. Multiple alterations, some very recently, have modified them extensively since the time they were accorded the ‘World Heritage Site’ status. The above examples are contrasted by sites ridden with conflict such as the Bamiyan Valley. This site has been placed under the ‘World Heritage In Danger’ list by UNESCO taking into account the destruction of the Buddha statues in the region. The act of vandalism itself has had dual implications. While causing an irreparable loss to mankind of its heritage, it also serves as an effective symbol of religious fanaticism that is a pressing concern of our times. The paper then moves on to explore the case of Dresden which lost its ‘World Heritage’ status with the construction of the Waldschlösschen Bridge. This is a particularly interesting case because with the absolute destruction of the city during the Second World War, it was necessary to reconstruct the historical city while simultaneously acknowledging and addressing the modern day requirements. During the reconstruction, with the readaptation of the spaces, it was almost impossible to replicate the original architectural program or to undertake such a large reconstruction project employing only the traditional techniques and materials. This essentially made it a new city constructed in the image of the old. The recent necessity of a growing city was met by the construction of a bridge that has caused it to lose its ‘World Heritage’ status. Finally, this paper endeavours to foster discussion of questions central to the definition of heritage such as what happens when we have to adapt a living space to avoid its deterioration and descent into dereliction by overuse. Does it necessarily lose its historical value? What exactly is Historical value?.

Comparative Genomics of Field Isolates of Mycobacterium bovis and M. caprae Provides Evidence for Possible Correlates with Bacterial Viability and Virulence

Mycobacteria of the Mycobacterium tuberculosis complex (MTBC) greatly affect humans and animals worldwide. The life cycle of mycobacteria is complex and the mechanisms resulting in pathogen infection and survival in host cells are not fully understood. Recently, comparative genomics analyses have provided new insights into the evolution and adaptation of the MTBC to survive inside the host. However, most of this information has been obtained using M. tuberculosis but not other members of the MTBC such as M. bovis and M. caprae. In this study, the genome of three M. bovis (MB1, MB3, MB4) and one M. caprae (MB2) field isolates with different lesion score, prevalence and host distribution phenotypes were sequenced. Genome sequence information was used for whole-genome and protein-targeted comparative genomics analysis with the aim of finding correlates with phenotypic variation with potential implications for tuberculosis (TB) disease risk assessment and control. At the whole-genome level the results of the first comparative genomics study of field isolates of M. bovis including M. caprae showed that as previously reported for M. tuberculosis, sequential chromosomal nucleotide substitutions were the main driver of the M. bovis genome evolution. The phylogenetic analysis provided a strong support for the M. bovis/M. caprae clade, but supported M. caprae as a separate species. The comparison of the MB1 and MB4 isolates revealed differences in genome sequence, including gene families that are important for bacterial infection and transmission, thus highlighting differences with functional implications between isolates otherwise classified with the same spoligotype. Strategic protein-targeted analysis using the ESX or type VII secretion system, proteins linking stress response with lipid metabolism, host T cell epitopes of mycobacteria, antigens and peptidoglycan assembly protein identified new genetic markers and candidate vaccine antigens that warrant further study to develop tools to evaluate risks for TB disease caused by M. bovis/M.caprae and for TB control in humans and animals.

Solderjet bumping technique used to manufacture a compact and robust green solid-state laser

Solder-joining using metallic solder alloys is an alternative to adhesive bonding. Laser-based soldering processes are especially well suited for the joining of optical components made of fragile and brittle materials such as glasses, ceramics and optical crystals due to a localized and minimized input of thermal energy. The Solderjet Bumping technique is used to assemble a miniaturized laser resonator in order to obtain higher robustness, wider thermal conductivity performance, higher vacuum and radiation compatibility, and better heat and long term stability compared with identical glued devices. The resulting assembled compact and robust green diode-pumped solid-state laser is part of the future Raman Laser Spectrometer designed for the Exomars European Space Agency (ESA) space mission 2018.