Modeling Hot Tearing during Solidification of Steels: Assessment and Improvement of Macroscopic Criteria through the Analysis of Two Experimental Tests

International audienceHot tearing is an unacceptable defect found in products and parts obtained by solidification processes such as ingot and continuous casting. It consists of the development of cracks during solidification, in regions that are not completely solidified, more precisely, in areas of mushy zones with a high fraction of solid (typically 0.9 and beyond), when the material undergoes deformations associated with tensile stress. In this study, two hot tearing tests have been studied in order to evaluate the predictive capability of several macroscopic criteria published in the literature. The first test is a new test specifically designed for constrained shrinkage by the present authors, while the second test is an ingot bending test developed in the 1980s. For both tests, a thermal-mechanical analysis is performed, in order to provide the key variables for the different selected criteria. A comparison with experimental results allows us to make a critical assessment of those criteria regarding their ability to predict crack occurrence. The criterion initially proposed by Won et al.[7] has been found to be the best suited for the prediction of solidification cracking. Because this criterion is essentially based on the "brittle temperature range," (BTR) critical considerations regarding nonequilibrium solidification have led to suggest an extension of this criterion. This new macroscopic criterion improves the prediction capacity

Sexual Size Dimorphism and Body Condition in the Australasian Gannet

Funding: The research was financially supported by the Holsworth Wildlife Research Endowment. Acknowledgments We thank the Victorian Marine Science Consortium, Sea All Dolphin Swim, Parks Victoria, and the Point Danger Management Committee for logistical support. We are grateful for the assistance of the many field volunteers involved in the study.Peer reviewedPublisher PD

Social sciences research in neglected tropical diseases 2: A bibliographic analysis

The official published version of the article can be found at the link below.Background There are strong arguments for social science and interdisciplinary research in the neglected tropical diseases. These diseases represent a rich and dynamic interplay between vector, host, and pathogen which occurs within social, physical and biological contexts. The overwhelming sense, however, is that neglected tropical diseases research is a biomedical endeavour largely excluding the social sciences. The purpose of this review is to provide a baseline for discussing the quantum and nature of the science that is being conducted, and the extent to which the social sciences are a part of that. Methods A bibliographic analysis was conducted of neglected tropical diseases related research papers published over the past 10 years in biomedical and social sciences. The analysis had textual and bibliometric facets, and focussed on chikungunya, dengue, visceral leishmaniasis, and onchocerciasis. Results There is substantial variation in the number of publications associated with each disease. The proportion of the research that is social science based appears remarkably consistent (<4%). A textual analysis, however, reveals a degree of misclassification by the abstracting service where a surprising proportion of the "social sciences" research was pure clinical research. Much of the social sciences research also tends to be "hand maiden" research focused on the implementation of biomedical solutions. Conclusion There is little evidence that scientists pay any attention to the complex social, cultural, biological, and environmental dynamic involved in human pathogenesis. There is little investigator driven social science and a poor presence of interdisciplinary science. The research needs more sophisticated funders and priority setters who are not beguiled by uncritical biomedical promises

HIV-1 Epidemic in the Caribbean Is Dominated by Subtype B

The molecular epidemiology of HIV-1 in the Caribbean has been described using partial genome sequencing; subtype B is the most common subtype in multiple countries. To expand our knowledge of this, nearly full genome amplification, sequencing and analysis was conducted.Virion RNA from sera collected in Haiti, Dominican Republic, Jamaica and Trinidad and Tobago were reverse transcribed, PCR amplified, sequenced and phylogenetically analyzed. Nearly full genomes were completed for 15 strains; partial pol was done for 67 strains. All but one of the 67 strains analyzed in pol were subtype B; the exception was a unique recombinant of subtypes B and C collected in the Dominican Republic. Of the nearly full genomes of 14 strains that were subtype B in pol, all were subtype B from one end of the genome to the other and not inter-subtype recombinants. Surprisingly, the Caribbean subtype B strains clustered significantly with each other and separate from subtype B from other parts of the pandemic.The more complete analysis of HIV-1 from 4 Caribbean countries confirms previous research using partial genome analysis that the predominant subtype in circulation was subtype B. The Caribbean strains are phylogenetically distinct from other subtype B strains although the biological meaning of this finding is unclear

Six pelagic seabird species of the North Atlantic engage in a fly-and-forage strategy during their migratory movements

Funding Information: We thank all the fieldworkers for their hard work collecting data. Funding for this study was provided by the Norwegian Ministry for Climate and the Environment, the Norwegian Ministry of Foreign Affairs and the Norwegian Oil and Gas Association along with 8 oil companies through the SEATRACK project (www. seapop. no/ en/ seatrack). Fieldwork in Norwegian colonies (incl. Svalbard and Jan Mayen) was supported by the SEAPOP program (www.seapop.no, grant no. 192141). The French Polar Institute (IPEV project 330 to O.C.) supported field operation for Kongsfjord kittiwakes. The work on the Isle of May was also supported by the Natural Environment Research Council (Award NE/R016429/1 as part of the UK-SCaPE programme delivering National Capability). We thank Maria Bogdanova for field support and data processing. Finally, we thank 3 anonymous reviewers for their help improving the first version of the manuscript.Peer reviewedPublisher PD

Are acoustical parameters of begging call elements of thin-billed prions related to chick condition?

Chicks of burrowing petrels use begging calls to advertise their hunger levels when parents arrived at the nest. In a previous study, adult thin-billed prions Pachyptila belcheri responded to higher begging call rates of their single chick by regurgitating larger meals. We tested whether acoustic parameters of begging call elements may also be involved in signalling. To describe variation in begging, we determined begging session parameters, namely the duration, number of calls and the mean and maximum rate of calling. We then digitised calls and carried out a semi-automatic extraction of six acoustic parameters of call elements, including mean and maximum acoustic frequency, the length of call elements and the location of the maximum frequency and amplitude within calls. Chicks showed strong individual differences in all parameters. While the session parameters were correlated with body condition and with the meal size the chick received, none of the acoustic parameters were related to body condition and provisioning. A cross-fostering experiment showed the same pattern, as only session parameters changed related to an experimentally altered body condition, while acoustical cues appear to play no role in signalling hunger levels. We suggest that this may be explained by the absence of sibling competition in these birds. As parents do not need to decide which chick to feed, immediate information on condition at the time of adult arrival may not be required

A Single CD8+ T Cell Epitope Sets the Long-Term Latent Load of a Murid Herpesvirus

The pathogenesis of persistent viral infections depends critically on long-term viral loads. Yet what determines these loads is largely unknown. Here, we show that a single CD8+ T cell epitope sets the long-term latent load of a lymphotropic gamma-herpesvirus, Murid herpesvirus-4 (MuHV-4). The MuHV-4 M2 latency gene contains an H2-Kd -restricted T cell epitope, and wild-type but not M2− MuHV-4 was limited to very low level persistence in H2d mice. Mutating the epitope anchor residues increased viral loads and re-introducing the epitope reduced them again. Like the Kaposi's sarcoma–associated herpesvirus K1, M2 shows a high frequency of non-synonymous mutations, suggesting that it has been selected for epitope loss. In vivo competition experiments demonstrated directly that epitope presentation has a major impact on viral fitness. Thus, host MHC class I and viral epitope expression interact to set the long-term virus load

Uncovering a Macrophage Transcriptional Program by Integrating Evidence from Motif Scanning and Expression Dynamics

Macrophages are versatile immune cells that can detect a variety of pathogen-associated molecular patterns through their Toll-like receptors (TLRs). In response to microbial challenge, the TLR-stimulated macrophage undergoes an activation program controlled by a dynamically inducible transcriptional regulatory network. Mapping a complex mammalian transcriptional network poses significant challenges and requires the integration of multiple experimental data types. In this work, we inferred a transcriptional network underlying TLR-stimulated murine macrophage activation. Microarray-based expression profiling and transcription factor binding site motif scanning were used to infer a network of associations between transcription factor genes and clusters of co-expressed target genes. The time-lagged correlation was used to analyze temporal expression data in order to identify potential causal influences in the network. A novel statistical test was developed to assess the significance of the time-lagged correlation. Several associations in the resulting inferred network were validated using targeted ChIP-on-chip experiments. The network incorporates known regulators and gives insight into the transcriptional control of macrophage activation. Our analysis identified a novel regulator (TGIF1) that may have a role in macrophage activation