3,134 research outputs found
The John Hunt Map of the First English Colony inNew England
A map of Fort St. George, the first official English settlement in New England, is proved to be a remarkably accurate document. Drawn by a draftsman who was obviously trained in state-of-the-art military cartography, it is a testament to the thoughtful planning of the adventure and the competence of the principal participants, as well as a reliable guide to archaeological investigation
Designing Your Home For Maximum Natural Lighting
There are many benefits to having more natural light in your home. The most obvious of these are the savings you can achieve with a reduced utility bill. According to the U.S. Department of Energy (2012), about 10% of household electricity usage comes from lighting. The more natural light you have in your house, the less lights you have to turn on, and the less electricity you use. Another benefit, also related to energy use, is natural light can help heat homes. One of the best reasons to design your home for natural light involves the health benefits gained through exposure to natural light
Surface Morphology of Human Airway Mucosa: Normal, Carcinoma or Cystic Fibrosis
The study presents preliminary qualitative findings of an investigation of grossly normal main and lobar bronchi at sites distant to well circumscribed tumour (n=15), adjacent to tumour (n=5) or of airways obtained during heart/lung transplantation in patients with cystic fibrosis (CF, n=3). In the normal airways the surface epithelium was on average 50 m thick, pseudostratified and rested on a roughly contoured basement membrane. A variety of cell types were identified although many were obscured by a dense covering of cilia, occasionally interrupted by foci of squamous metaplasia. Submucosal gland structure was observed in chance vertical fractures of the airway wall. Tissue adjacent to tumour showed sloughing, squamous metaplasia, pleomorphism and cell surface projections of stubby microvilli or tortuous microridges. The surface morphology of the three CF patients showed no feature unique to the condition, albeit secretions were found adherent to surface lining associated with isolated bacteria and groups of free cells (probably lymphocytes). In each of the three cases the epithelial surface was densely ciliated, interspersed with mucous (i.e., goblet) cells. Submucosal gland collecting ducts had dilated lumena
Translational Neuroscience & Mental Disorders—bridging the gap between animal models and the human condition
Response of Laryngeal and Tracheo-Bronchial Surface Lining to Inhaled Cigarette Smoke in Normal and Vitamin A-Deficient Rats: A Scanning Electron Microscopic Study.
The effects on surface morphology of airway epithelium of cigarette smoke (CS) inhalation alone (experiments one and two) or of CS in combination with hypovitaminosis A (experiment two) was investigated using specific pathogen free rats. Eight morphologically distinct cell types were distinguished overall. Apart from atypical squamous lesions each of the other cell types could be found in varying proportions in all experimental groups. CS alone caused an increase in the frequency with which intra-lumenal mucus was seen and an increase in the occurrence of secretory cells of types IV (i.e.,\u27merocrine\u27) and V (i.e.,\u27apocrine\u27). In experiment one, the area of trachea covered by cilia as determined by point counting increased significantly (P\u3c0.01). Hypovitaminosis A was induced by lowering the dietary intake of vitamin A to a minimum, defined level. Rats showed an approximately 75% decrease in plasma retinol levels and a 95-100% decrease in hepatic stores of vitamin A. At this level, hypovitaminosis A alone had no significant effect on airway epithelial morphology. Foci of squamous metaplasia (squamous cells of type VIIIa) were found in all groups but extensive squamous metaplasia of the larynx and squamous lesions of atypical appearance (type VIIIb) were found only in the vitamin deficient group exposed to CS. The results suggest the synergistic effects of reduced vitamin A and CS may be important in the induction of atypical squamous changes which may predispose the airway to the development of squamous carcinoma
Sampling Deformed, Intersecting Surfaces with Quadtrees
A quadtree algorithm is developed to render deformed, intersecting parametric surfaces with inside-outside functions.
The task of adaptively sampling a surface may be broken into two parts: a subdivision mechanism for recursively
subdividing a surface, and a set of subdivision criteria for determining where to subdivide. A surface quadtree is a
collection of parametric samples arranged in a quadtree. A restricted quadtree is a quadtree whose neighboring elements
must be the same size within a factor of two. Restricted surface quadtrees are shown to be an effective recursive
subdivision mechanism. The quadtree samples are concentrated along silhouette and intersection boundaries, and
in regions of high curvature, using several subdivision criteria. The recursive subdivision algorithm that finds the
sample points is proven to have a complexity of O(n) along boundary curves, where n is the linear resolution of
the boundary in parameter space. A new proximity subdivision criterion concentrates samples where two surfaces
potentially intersect. An extended modeling hierarchy that includes deformations is demonstrated with several
examples. The initial implementation using surface quadtrees is moderately more efficient and substantially more
robust than uniform Sampling techniques; surface quadtrees are potentially much more efficient and robust than
uniform sampling at rendering deformed, intersecting surfaces
On the origin of aurorae on Mars
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95268/1/grl20829.pd
REDEFINING CpG ISLANDS USING A HIDEEN MARKOV MODEL
The DNA of most vertebrates is depleted in CpG dinucleotides; C followed by a G in the 5’ to 3’ direction. CpGs are the target for DNA methylation, a chemical modification of cytosine (C) heritable during cell division and the most well characterized epigenetic mechanism. The remaining CpGs tend to cluster in regions referred to as CpG islands (CGI). Knowing CGI locations is important because they mark functionally relevant epigenetic loci in development and disease. For various mammals, including human, a readily available and widely used list of CGI is available from the UCSC Genome Browser. This list was derived using algorithms that search for regions satisfying a definition of CGI proposed by Gardiner-Garden and Frommer more than 20 years ago. Recent findings, enabled by advances in technology that permit direct measurement of epigenetic endpoints at a whole-genome scale, motive the need to adapt the current CGI definition. In this paper we propose a procedure, guided by hidden Markov models, that permits an extensible approach to detecting CGI. The main advantage of our approach over others is that it summarized the evidence for CGI status as probability scores. This provides flexibility in the definition of a CGI and facilitates the creation of CGI lists for other species. The utility of this approach is demonstrated by generating the first CGI lists for invertebrates, and the fact that we can create CGI lists that substantially increases overlap with recently discovered epigenetic marks. A CGI list and the probability scores, as a function of genome location,for each specie are available at http://www.rafalab.org
Challenges in decomposing encodings of verification problems
Modern program verifiers use logic-based encodings of the verification problem that are discharged by a back end reasoning engine. However, instances of such encodings for large programs can quickly overwhelm these back end solvers. Hence, we need techniques to make the solving process scale to large systems, such as partitioning (divide-and-conquer) and abstraction.
In recent work, we showed how decomposing the formula encoding of a termination analysis can significantly increase efficiency. The analysis generates a sequence of logical formulas with existentially quantified predicates that are solved by a synthesis-based program analysis engine. However, decomposition introduces abstractions in addition to those required for finding the unknown predicates in the formula, and can hence deteriorate precision. We discuss the challenges associated with such decompositions and their interdependencies with the solving process
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