Expert system verification concerns in an operations environment

The Space Shuttle community is currently developing a number of knowledge-based tools, primarily expert systems, to support Space Shuttle operations. It is proposed that anticipating and responding to the requirements of the operations environment will contribute to a rapid and smooth transition of expert systems from development to operations, and that the requirements for verification are critical to this transition. The paper identifies the requirements of expert systems to be used for flight planning and support and compares them to those of existing procedural software used for flight planning and support. It then explores software engineering concepts and methodology that can be used to satisfy these requirements, to aid the transition from development to operations and to support the operations environment during the lifetime of expert systems. Many of these are similar to those used for procedural hardware

Awakening the Classics

Professor Chris Blackwell transports ancient literature to the digital world

Alien Registration- Goodwin, Mary (Rumford, Oxford County)

https://digitalmaine.com/alien_docs/13607/thumbnail.jp

Mapping Memory in Tran’s Vietnamerica

In her article Mapping Memory in Tran\u27s Vietnamerica Mary Goodwin explores the use of maps, landscape paintings, and other topographic images in Gia-Bao Tran\u27s graphic memoir chronicling the postmemory of the US-American son of wartime refugees. Tran\u27s family immigrated to the United States in 1975 following the fall of Saigon. Tran knew nothing of his parents\u27 hardships and struggle to escape Vietnam until he returned for relatives\u27 funerals in his 20s. Similar to Spiegelman\u27s Maus, Vietnamerica is a mixed-media memoir containing photographs, maps, and comics in various styles. Following Hirsch\u27s lead in demonstrating the special historical value of photographs in Maus, Goodwin argues for the unique value of the maps and landscape visuals Tran uses to relate Vietnam\u27s history and his family\u27s experiences. The medium of the graphic novel presents its own challenges as auto/biography and historical record and topographic images introduce a complication in juxtaposing the real public world with the personal and individual. Thus Vietamerica becomes an ever-shifting kaleidoscope of perspective on a multi-dimensional history of war, exile, and personal struggles to come to terms with cultural and familial identity

Establishment of a Novel Patient hiPSC-derived in vitro Blood-Brain Barrier Model of Collagen IV Small Vessel Disease

Cerebral small vessel disease (SVD) is a prevalent cause of stroke (25-30%) and dementia (45%). Despite its frequency, little is known about the cause and disease progression of SVD. Matrisome alteration leading to blood-brain barrier (BBB) dysfunction is thought to play a role. Sporadic cases are exacerbated by age and vascular risk factors, predominantly affecting the elderly. However, mutations in Collagen IV α1/α2 (COL4A1/2), a highly abundant matrisome protein, cause monogenic SVD, which shares many clinical features with the sporadic form. In order to better understand the pathomolecular mechanisms leading to SVD, human induced pluripotent stem cells (hiPSC) generated from patients with mutations in COL4A1/2 genes (COL4A1G755R and COL4A2G702D), isogenic controls and multiple wild-type (WT) control lines were used to establish a novel in vitro BBB model of Collagen IV SVD. Encompassing hiPSC-derived brain microvascular endothelial cells (BMEC), mural cells (MC) and astrocytes, the model was used to probe the phenotype of COL4A1/2 SVD. Differentiation of hiPSC into BMEC was extensively optimised to overcome high variability between different hiPSC lines. Once established, hiPSC-BMEC were tested with functional assays including transendothelial electrical resistance (TEER), permeability assays (4kDa FITC-Dextran and Sodium Fluorescein), LDL-uptake and tube formation. hiPSC-BMEC were then combined with hiPSC-MC and hiPSC-astrocytes into a Transwell® co-culture model. WT hiPSC-derived BMEC exhibit high TEER of ~3000-4000Ωxcm2, which is increased and maintained over two weeks in co-culture with astrocytes. Limited, short-term increase in TEER is seen in co-culture with MC. Aspects of the COL4A1/2 SVD disease phenotype were reproduced in vitro. COL4A2G702D BMEC exhibit lower tight junction protein expression; while COL4A1G755R BMEC demonstrate discontinuous tight junctions. COL4A2G702D BMEC also show defective P-glycoprotein (P-gp)-mediated Rhodamine123 efflux compared to the isogenic control, which is suggestive of a transport deficiency across the barrier. COL4A1G755R and COL4A2G702D BMEC and MC have increased levels of MMPs. Notably, these findings replicate what is seen in patients, strengthening the hypothesis that matrisome alterations are important in SVD.Rosetrees Trust, British Heart Foundation, Alzheimer’s Association and Stroke Association

A three dimensional comparison of the facial morphology of unilateral cleft lip and palate patients with a control group

The quest to describe and quantify three-dimensional (3D) facial form has spanned many centuries, ancient Greek sculptors designed frames for recording facial shape in order to faithfully reproduce likenesses in stone, and also contemplated the aesthetic significance of various proportionate measures. Greek mathematicians and philosophers attempted to interpret beauty in terms of divine proportions (Huntley 1970). Historically, it has long been recognised that two-dimensional (2D) representations of human anatomy are limited. The human body is three-dimensional, and not comprised of regular geometric structures. It has no obvious internal reference system and there is no easy way of applying an external reference system, therefore the measurement of the body and its representation in 3D is not an easy task. The need for accurate measurement and representation of the face is particularly acute because of the vital importance of appearance, and this is especially so for those born with a craniofacial anomaly such as unilateral cleft lip and palate (UCLP) (Shaw 1988). The need to objectively quantify face shape in those born with facial anomalies such as UCLP is necessary, not just in terms of clinical audit, but to determine the best treatment regimes for good aesthetic outcome. This is a subject of debate within both the orthodontic and surgical community with many inter-centre studies being carried out (Shaw et al. 1992; MacKay et al. 1994, Roberts-Harry et al. 1996). A great deal of research on facial growth has been undertaken using, on the whole, 2D methods of data collection, such as lateral cephalometric radiographs and photography. The motivation for this work has arisen from the need to quantify objectively in 3D the differences in the facial soft tissue morphology between a group of children born with UCLP and an equivalent control group. This thesis studies the work of one surgeon and compares the facial morphology of those children born with UCLP with a normal population of the same age, sex and ethnic origin using a method of 3D analysis. Recent reports suggest the need to quantify surgical outcome of children born with UCLP and assess the aesthetic and functional effects of surgery (Shaw et al. 1992, Shaw et al. 1996, Williams et al 1996) If we want to characterise the shape of the face and its changes with growth the whole facial surface needs to be recorded in 3D. A finely sampled recording of the face in 3D is also required if the shape of the facial surface is to be determined and analysed. The hypothesis of this thesis is that there is no difference in the soft tissue facial morphology of UCLP patients who have been carefully operated on by one surgeon, compared with a control group. In order to test the hypothesis the facial soft tissue morphology of a control group and a group of children with UCLP were studied. There were a total of 73 children in the UCLP group and 245 in the control group. The control group and the UCLP group were divided by age and sex, so that differences in soft tissue facial morphology which occur at different ages could be investigated. The facial morphology of the female and male UCLP group were then compared with each other. The female and male cleft groups were also compared to the equivalent female and male control group. One surgeon operated on all the UCLP groups. The majority of the clefts being studied were left-sided, those with a right-sided cleft were mirror-imaged to make them left sided and were included in this study. The control groups were all Skeletal I (glossary) cases, with no history of orthodontic treatment or tooth extraction. The children in this study were all Caucasians (glossary) and the facial data were collected from our clinical centres in East and Central London. The data used in both the UCLP and control group is cross-sectional and were collected using the non-invasive, no contact system of 3D optical surface scanning developed at University College London (UCL), (Moss et al 1989). This method of data collection is ideally suited to measurement and comparison of soft tissues and also allows direct reference to equivalent control populations. The scanning of faces produces sufficient 3D co-ordinate measurements of the facial surface to allow the use of computer graphics to produce a photo-realistic image of the 3D surface, which may be, analysed and manipulated. All the facial datasets within each group were averaged to produce an average face for each group. Averaging all the individual facial data in this way permits comparison between the groups. The average facial scans were then registered, which provides an objective, quantitative comparison between each group. In order to quantify the changes, the nose and specific facial distances were also measured. Summary of Results Female cleft compared with male cleft: The noses of the male cleft group at ages 4-8 were longer and wider than that of the female cleft group of the same age. At age 9-12 the nose of the female group was longer and wider than that of the equivalent male group. At age 13-16 the female nose was still slightly longer than that of the equivalent male group. The chin was more prominent in the male cleft group at ages 4-8 and 13-16 years, whereas at age 9-12 the chin, cheeks and lips of the female cleft group were more prominent than those of the males. Female cleft compared with female control: The soft tissues of the female cleft groups were more retropositioned than the female control groups at all ages. The noses of the female clefts were flatter than those of the controls, alar base width was also greater in the female cleft groups. Male cleft compared with male control: The tip of the male cleft noses in all age groups was flatter than that of the controls, alar base width was variable within the groups. The cheeks and lips of the male cleft group at all ages were more retropositioned than the controls. The chin was more prominent at ages 4-8 and 9-12 but at age 13-16 it was the same as that of the equivalent control group. Conclusion There was a significant difference in the facial morphology of unilateral cleft lip and palate patients compared with controls at all ages

Economic Statistics and U.S. Agricultural Policy

Economic statistics can be used to inform policy as it is being designed, avoid policy design mistakes, or implement government programs once they are established into law. Oftentimes, statistics are used for all three purposes. This paper considers the relationships between statistics and agricultural policy in the case of the United States. We address first the broad historical picture of U.S. official economic statistics concerning agriculture, and then turn to selected examples that relate policies to economic statistics in more detail. The examples show diversity in the interplay between statistics and policy. As policies have become broader in scope, addressing not only farm commodity markets but also differences among farms and a widening set of activities on farms, policymakers have asked for more detailed information about the financial situation of individual farm businesses and households, sources of risk in farm returns, and production practices that affect the environment.Agricultural policy, Data collection and estimation, Economic history of U.S. agriculture, Agricultural and Food Policy, Q18, C8, N52,