1,541 research outputs found
Comet Machholz (C/2004 Q2): morphological structures in the inner coma and rotation parameters
Extensive observations of comet C/2004 Q2 (Machholz) were carried out between
August 2004 and May 2005. The images obtained were used to investigate the
comet's inner coma features at resolutions between 350 and 1500 km/pixel. A
photometric analysis of the dust outflowing from the comet's nucleus and the
study of the motion of the morphological structures in the inner coma indicated
that the rotation period of the nucleus was most likely around 0.74 days. A
thorough investigation of the inner coma morphology allowed us to observe two
main active sources on the comet's nucleus, at a latitude of +85{\deg} \pm
5{\deg} and +45{\deg} \pm 5{\deg}, respectively. Further sources have been
observed, but their activity ran out quite rapidly over time; the most relevant
was at latcom. = 25{\deg} \pm 5{\deg}. Graphic simulations of the geometrical
conditions of observation of the inner coma were compared with the images and
used to determine a pole orientation at RA=95{\deg} \pm 5{\deg}, Dec=+35{\deg}
\pm 5{\deg}. The comet's spin axis was lying nearly on the plane of the sky
during the first decade of December 2004.Comment: 29 pages, 8 figures, 3 table
Scheduling Jobs in Flowshops with the Introduction of Additional Machines in the Future
This is the author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/expert-systems-with-applications/.The problem of scheduling jobs to minimize total weighted tardiness in flowshops,\ud
with the possibility of evolving into hybrid flowshops in the future, is investigated in\ud
this paper. As this research is guided by a real problem in industry, the flowshop\ud
considered has considerable flexibility, which stimulated the development of an\ud
innovative methodology for this research. Each stage of the flowshop currently has\ud
one or several identical machines. However, the manufacturing company is planning\ud
to introduce additional machines with different capabilities in different stages in the\ud
near future. Thus, the algorithm proposed and developed for the problem is not only\ud
capable of solving the current flow line configuration but also the potential new\ud
configurations that may result in the future. A meta-heuristic search algorithm based\ud
on Tabu search is developed to solve this NP-hard, industry-guided problem. Six\ud
different initial solution finding mechanisms are proposed. A carefully planned\ud
nested split-plot design is performed to test the significance of different factors and\ud
their impact on the performance of the different algorithms. To the best of our\ud
knowledge, this research is the first of its kind that attempts to solve an industry-guided\ud
problem with the concern for future developments
Loss of the Intellectual Disability and Autism Gene Cc2d1a and Its Homolog Cc2d1b Differentially Affect Spatial Memory, Anxiety, and Hyperactivity
Hundreds of genes are mutated in non-syndromic intellectual disability (ID) and autism spectrum disorder (ASD), with each gene often involved in only a handful of cases. Such heterogeneity can be daunting, but rare recessive loss of function (LOF) mutations can be a good starting point to provide insight into the mechanisms of neurodevelopmental disease. Biallelic LOF mutations in the signaling scaffold CC2D1Acause a rare form of autosomal recessive ID, sometimes associated with ASD and seizures. In parallel, we recently reported that Cc2d1a-deficient mice present with cognitive and social deficits, hyperactivity and anxiety. In Drosophila, loss of the only ortholog of Cc2d1a, lgd, is embryonically lethal, while in vertebrates, Cc2d1a has a homolog Cc2d1b which appears to be compensating, indicating that Cc2d1a and Cc2d1b have a redundant function in humans and mice. Here, we generate an allelic series of Cc2d1a and Cc2d1b LOF to determine the relative role of these genes during behavioral development. We generated Cc2d1b knockout (KO), Cc2d1a/1b double heterozygous and double KO mice, then performed behavioral studies to analyze learning and memory, social interactions, anxiety, and hyperactivity. We found that Cc2d1a and Cc2d1b have partially overlapping roles. Overall, loss of Cc2d1b is less severe than loss of Cc2d1a, only leading to cognitive deficits, while Cc2d1a/1b double heterozygous animals are similar to Cc2d1a-deficient mice. These results will help us better understand the deficits in individuals with CC2D1A mutations, suggesting that recessive CC2D1B mutations and trans-heterozygous CC2D1A and CC2D1B mutations could also contribute to the genetics of ID
Inclusivity in TAS research:An example of EDI as RRI
Responsible research and innovation (RRI) aims to achieve the goal of making research activities responsible and ethical. To those ends, it is vital for researchers to actively engage with equality, diversity and inclusion (EDI) which, if not attended to, may detrimentally affect both potential research participants and the research itself.
Our paper offers an account of our ongoing discussions surrounding the importance of EDI when designing our research, how we employed EDI to intentionally make our recruitment process more inclusive, and our ongoing planning to make all our research activities as inclusive, diverse, and accessible as possible.
There is no one-size-fits-all approach for adopting EDI principles in RRI, however, we posit that their consideration is essential for research communities who wish their work to represent the perspectives of those who will be affected by future novel technologies
Hybrid model for the design of a deep-lane multisatellite AVS/RS
The autonomous vehicle storage and retrieval system (AVS/RS) significantly improves the responsiveness and throughput of the traditional automated storage and retrieval system (AS/RS) in regard to handling unit loads. The AVS/RS consists of multiple tiers connected to an elevator system and is equipped with at least two autonomous vehicles, that is, a shuttle and satellite. Other necessary equipment are the lifts and input/output buffer areas. This paper aims to present and apply an original hybrid analytical-simulative model for the design of a deep-lane and multisatellite AVS-RS by evaluating and controlling the system performance. This AVS-RS is equipped with multiple free and non-free satellites for each tier. As an original contribution, this study reviews the literature on AVS/RS according to the introduction of multiple features categorized into five homogeneous groups: (1) rack configuration, (2) vehicle kinematics and configuration, (3) dispatching rules, (4) modeling approach, and (5) validation. Two of the most critical issues in existing research studies are the random arrival time of storage and retrieval transactions and the random storage policy. The proposed modeling approach is data-driven and based on realistic assumptions, filling the gap between the literature and real applications. This hybrid model is applied to a case study of the beverage industry according to a what-if comparative and competitive multiscenario analysis. This data-driven assessment supports the decision-making process on the number of satellites for each tier, while simultaneously controlling the service and waiting times, system throughput, and vehicle utilization. The analysis based on the maximum system throughput estimation demonstrates that introducing more than two satellites does not increase the productivity of the system
ApoE-deficient mice and fenritinide: a structural study of the skin
Fenretinide, a synthetic retinoid derivative first investigated for cancer prevention and treatment, has been shown to ameliorate glucose tolerance and the plasma lipid profile, and to reduce body fat mass. Since these effects, together with its ability to inhibit ceramide synthesis, have suggested that fenretinide may display anti-atherosclerotic effects, the purpose of our work was to evaluate the effect of fenretinide on accumulation of lipids on the skin of a dyslipidemic mouse model that spontaneously develops atherosclerosis. To this aim, 9-weeks-old apoE-knockout (EKO) female mice were fed for 12 weeks with a Western diet, without (control) or with (0.1% w/w) fenretinide. At sacrifice, skin biopsies were excised from the thoracic region, dissected in smaller fragments and processed for structural morphology analysis on both paraffin and semithin sections. As a reference, wild-type (WT) mice were likewise treated. Morphological analysis did not show any significant difference between the skin of treated and untreated WT mice. In both the experimental groups, indeed, the epidermis appeared build-up of ordinated overlapped layers of cells and in the dermis there were no signs of alteration. The presence of foam cells was detected only in EKO mice treated and untreated. Other morphological alterations were also visible, although shared almost equally in EKO-Ctrl and EKO-Fen animals. Our data suggest that fenretinide slightly interferes with lipid accumulation in the skin of EKO mice
Exploring undergraduate students’ productive struggles in a quantitative literacy course: Implications for the development of tutoring
The present study explores undergraduate students’ productive struggles in a Quantitative Literacy (QL) course, when doing exercises on the statistical concept of confidence intervals (CIs) within the context of odds ratios (ORs), embedded in everyday authentic contexts. The research methodology employed in this study is lesson study, in which tutors and researchers work together to plan the research tutorial, observe and teach it, and reflect on the instruction in general within the research tutorial. Data for this study comprises video- and audio- recorded transcriptions of the observation and teaching, and reflections of tutors on research tutorials. In addition, samples of students’ work and their achievements in assessments were analysed. Results from the study showed that the students’ struggles were initiated when their prior knowledge was not sufficient for them to understand the concept of CIs in relation to ORs. The results also highlight some of the ways in which tutors can notice and address students’ productive struggles during tutorials. Future researchers should focus on identifying which instructional approaches can promote and support prolific productive struggles for students during tutoring
Constitutive expression of E- and P-selectin cognate ligands in human endothelial cells.
On human endothelial cells from umbilical cord (HUVEC) are present, in addition to E- and P-selectins, their cognate ligands. Differently from selectins, the ligand expression is constitutive and not modulated by interleukin-1beta. Such ligands appear to be different from the ones present in promyelocytic cells in order to promote cell adhesion to immobilized selectins. The expression of selectin-ligands on HUVEC cells suggest that selectins can participate in endothelial signalling besides their role as adhesion molecules for circulating blood cells. However, despite their role in chemotaxis, selectins do not contribute to HUVEC tube formation in Matrigel
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