1,800 research outputs found
Secular Evolution of Galaxy Morphologies
Today we have numerous evidences that spirals evolve dynamically through
various secular or episodic processes, such as bar formation and destruction,
bulge growth and mergers, sometimes over much shorter periods than the standard
galaxy age of 10-15 Gyr. This, coupled to the known properties of the Hubble
sequence, leads to a unique sense of evolution: from Sm to Sa. Linking this to
the known mass components provides new indications on the nature of dark matter
in galaxies. The existence of large amounts of yet undetected dark gas appears
as the most natural option. Bounds on the amount of dark stars can be given
since their formation is mostly irreversible and requires obviously a same
amount of gas.Comment: 8 pages, Latex2e, crckapb.sty macros, 1 Postscript figure, replaced
with TeX source; To be published in the proceeedings of the "Dust-Morphology"
conference, Johannesburg, 22-26 January, 1996, D. Block (ed.), (Kluwer
Dordrecht
Clinical characteristics of ovarian cancer classified by BRCA1, BRCA2, and RAD51C status.
We evaluated homologous recombination deficient (HRD) phenotypes in epithelial ovarian cancer (EOC) considering BRCA1, BRCA2, and RAD51C in a large well-annotated patient set. We evaluated EOC patients for germline deleterious mutations (n = 899), somatic mutations (n = 279) and epigenetic alterations (n = 482) in these genes using NGS and genome-wide methylation arrays. Deleterious germline mutations were identified in 32 (3.6%) patients for BRCA1, in 28 (3.1%) for BRCA2 and in 26 (2.9%) for RAD51C. Ten somatically sequenced patients had deleterious alterations, six (2.1%) in BRCA1 and four (1.4%) in BRCA2. Fifty two patients (10.8%) had methylated BRCA1 or RAD51C. HRD patients with germline or somatic alterations in any gene were more likely to be high grade serous, have an earlier diagnosis age and have ovarian and/or breast cancer family history. The HRD phenotype was most common in high grade serous EOC. Identification of EOC patients with an HRD phenotype may help tailor specific therapies.This work was supported by National Institutes of Health grants R01-CA122443, P50-CA136393, P30-CA15083, and the Fred C. and Katherine B. Andersen Foundation. We thank Gary Kenney, M.D. for pathology review of tumor tissue. We thank Craig Luccarini, Caroline Baynes from University of Cambridge for assisting our sample sequencing
Self-assembly of Microcapsules via Colloidal Bond Hybridization and Anisotropy
Particles with directional interactions are promising building blocks for new
functional materials and may serve as models for biological structures.
Mutually attractive nanoparticles that are deformable due to flexible surface
groups, for example, may spontaneously order themselves into strings, sheets
and large vesicles. Furthermore, anisotropic colloids with attractive patches
can self-assemble into open lattices and colloidal equivalents of molecules and
micelles. However, model systems that combine mutual attraction, anisotropy,
and deformability have---to the best of our knowledge---not been realized.
Here, we synthesize colloidal particles that combine these three
characteristics and obtain self-assembled microcapsules. We propose that mutual
attraction and deformability induce directional interactions via colloidal bond
hybridization. Our particles contain both mutually attractive and repulsive
surface groups that are flexible. Analogous to the simplest chemical bond,
where two isotropic orbitals hybridize into the molecular orbital of H2, these
flexible groups redistribute upon binding. Via colloidal bond hybridization,
isotropic spheres self-assemble into planar monolayers, while anisotropic
snowman-like particles self-assemble into hollow monolayer microcapsules. A
modest change of the building blocks thus results in a significant leap in the
complexity of the self-assembled structures. In other words, these relatively
simple building blocks self-assemble into dramatically more complex structures
than similar particles that are isotropic or non-deformable
As a Pediatrician, I Don’t Know the Second, Third, or Fourth Thing to Do: A Qualitative Study of Pediatric Residents’ Training and Experiences in Behavioral Health
Despite a mandated 1-month rotation in developmental-behavioral pediatrics (DBP), pediatric residents report inadequate training in behavioral health care. As a first step in much needed curriculum development in this area, this study sought to assess learner experiences regarding the management of behavioral health problems during residency. Four focus groups were conducted for residents in years 1-3 of training in 2 residency programs in a northeastern state. Transcripts were analyzed and coded by researchers through qualitative classical content analysis. The exploratory analysis revealed 9 key themes: time requirements, rapport building, resources and referrals for behavioral health, psychiatric medications, diagnosis vs. treatment, working with families, the importance of behavioral health, fears of working with a pediatric population, and training issues. These qualitative data further identify gaps in the behavioral health training of pediatric residents and may inform future innovations in training curricula
Total Laparoscopic Restorative Proctocolectomy: Are There Advantages Compared with the Open and Hand-Assisted Approaches?
PURPOSE: A randomized, controlled trial comparing hand-assisted laparoscopic restorative proctocolectomy with open surgery did not show an advantage for the laparoscopic approach. The trial was criticized because hand-assisted laparoscopic restorative proctocolectomy was not considered a true laparoscopic proctocolectomy. The objective of the present study was to assess whether total laparoscopic restorative proctocolectomy has advantages over hand-assisted laparoscopic restorative proctocolectomy with respect to early recovery. METHODS: Thirty-five patients underwent total laparoscopic restorative proctocolectomy and were compared to 60 patients from a previously conducted randomized, controlled trial comparing hand-assisted laparoscopic restorative proctocolectomy and open restorative proctocolectomy. End points included operating time, conversion rate, reoperation rate, hospital stay, morbidity, quality of life, and costs. The Medical Outcomes Study Short Form 36 and the Gastrointestinal Quality of Life Index were used to evaluate general and bowel-related quality of life. RESULTS: Groups were comparable for patient characteristics, such as sex, body mass index, preoperative disease duration, and age. There were neither conversions nor intraoperative complications. Median operating time was longer in the total laparoscopic compared with the hand-assisted laparoscopic group (298 vs. 214 minutes; P < 0.001). Morbidity and reoperation rates in the total laparoscopic, hand-assisted laparoscopic, and open groups were comparable (29 vs. 20 vs. 23 percent and 17 vs.10 vs. 13 percent, respectively). Median hospital-stay was 9 days in the total laparoscopic group compared with 10 days in the hand-assisted laparoscopic group and 11 days in the open group (P = not significant). There were no differences in quality of life and total costs. CONCLUSIONS: There were no significant short-term benefits for total laparoscopic compared with hand-assisted laparoscopic restorative proctocolectomy with respect to early morbidity, operating time, quality of life, costs, and hospital sta
Star Architecture as Socio-Material Assemblage
Taking inspiration from new materialism and assemblage, the chapter deals with star architects and iconic buildings as socio-material network effects that do not pre-exist action, but are enacted in practice, in the materiality of design crafting and city building. Star architects are here conceptualized as part of broader assemblages of actors and practices ‘making star architecture’ a reality, and the buildings they design are considered not just as unique and iconic objects, but dis-articulated as complex crafts mobilizing skills, technologies, materials, and forms of knowledge not necessarily ascribable to architecture. Overcoming narrow criticism focusing on the symbolic order of icons as unique creations and alienated repetitions of capitalist development, the chapter’s main aim is to widen the scope of critique by bridging culture and economy, symbolism and practicality, making star architecture available to a broad, fragmented arena of (potential) critics, unevenly equipped with critical tools and differentiated experiences
Recommended from our members
How market standards affect building design: the case of low energy design in commercial offices
This paper develops existing work on building design through a focus on one important yet understudied form of regulation: market standards. Market standards are agreed upon definitions of ‘necessary’ provision in buildings and are fundamental in ‘formatting’ markets and determining the value of a building in the market. The paper presents a case study of the design of ten commercial offices in London, UK, the effects of market standards on the designs and on the potential for the development of lower energy buildings. Theoretically, the paper integrates literatures on standards, institutions and markets to argue that market standards do important ‘work’ in design processes that requires closer scrutiny. In particular, we show that market standards: are an important form of normative and cultural regulation in the field of commercial office design; format and act as calculative devices in property markets; and result in forms of knowledge diminution that break the relationship between building design and occupiers’ practices. Together, these effects result in particular designs being legitimised and valued, and lower energy designs being delegitimised, devalued and pushed to the periphery of the attention of commercial office designers
Genetic Diversity and Population Parameters of Sea Otters, Enhydra lutris, before Fur Trade Extirpation from 1741–1911
All existing sea otter, Enhydra lutris, populations have suffered at least one historic population bottleneck stemming from the fur trade extirpations of the eighteenth and nineteenth centuries. We examined genetic variation, gene flow, and population structure at five microsatellite loci in samples from five pre-fur trade populations throughout the sea otter's historical range: California, Oregon, Washington, Alaska, and Russia. We then compared those values to genetic diversity and population structure found within five modern sea otter populations throughout their current range: California, Prince William Sound, Amchitka Island, Southeast Alaska and Washington. We found twice the genetic diversity in the pre-fur trade populations when compared to modern sea otters, a level of diversity that was similar to levels that are found in other mammal populations that have not experienced population bottlenecks. Even with the significant loss in genetic diversity modern sea otters have retained historical structure. There was greater gene flow before extirpation than that found among modern sea otter populations but the difference was not statistically significant. The most dramatic effect of pre fur trade population extirpation was the loss of genetic diversity. For long term conservation of these populations increasing gene flow and the maintenance of remnant genetic diversity should be encouraged
Stochastic Modeling for the Expression of a Gene Regulated by Competing Transcription Factors
It is widely accepted that gene expression regulation is a stochastic event. The common approach for its computer simulation requires detailed information on the interactions of individual molecules, which is often not available for the analyses of biological experiments. As an alternative approach, we employed a more intuitive model to simulate the experimental result, the Markov-chain model, in which a gene is regulated by activators and repressors, which bind the same site in a mutually exclusive manner. Our stochastic simulation in the presence of both activators and repressors predicted a Hill-coefficient of the dose-response curve closer to the experimentally observed value than the calculated value based on the simple additive effects of activators alone and repressors alone. The simulation also reproduced the heterogeneity of gene expression levels among individual cells observed by Fluorescence Activated Cell Sorting analysis. Therefore, our approach may help to apply stochastic simulations to broader experimental data
Tracking habitus across a transnational professional field
The sociology of the professions has shied away from cross-national comparative work. Yet research in different professional jurisdictions emphasizes the transnational nature of professional fields. Further work is therefore needed that explores the extent to which transnational professional fields are characterized by unity or heterogeneity. To that end, this article presents the results of a qualitative interrogation of the habitus of partners in ‘Big 4’ professional service firms across, primarily, five countries (Bangladesh, Canada, France, Spain and the UK). Marked differences are observed between the partner habitus in Bangladesh and the other countries studied in terms of entrepreneurial and public service dispositions. In turn, these findings highlight the methodological relevance of habitus for both the sociology of the professions and comparative capitalism literatures: for the former, habitus aids in mapping the dynamics of transnational professional fields; for the latter, habitus can elucidate the informal norms and conventions of national business systems
- …