331 research outputs found
A comparison of laser based ranging systems for AR/C category 1: Hardware
This paper will present some aspects of the effect of inherent laser effects on the performance of CW-Tone modulated and FM-CW laser ranging techniques. It will be shown that performance of these techniques is affected in different ways by inherent laser characteristics and previous comparisons of the techniques should be modified to reflect more realistic conditions. An overall survey of laser ranging will be given to place the CW and FM-CW techniques in perspective. It will be seen that the newly introduced FM-CW laser radar has potentially far superior performance to CW-Tone modulated systems now proposed for use in space rendezvous and capture systems
A comparison of laser-based ranging systems for AR/C
The three most common types of laser target ranging (time-of-flight, tone modulated, and FM-CW) are discussed in terms of principle of operation. The first, time-of-flight, is shown to depend more on the ability of support electronics than the fundamentals of the concept. Examples in the literature are cited to show the remarkably good performance of time-of-flight systems. A system developed in Finland was shown to have an incremental ranging capability of a few millimeters. The system is not only robust; it does not include additions such as reference legs and the like, which are expected, for improvement in performance. Though not immediately obvious, the second technique, tone modulated ranging is somewhat of an extension of the time-of-flight technique. Finally, the FM-CW technique is presented. This is completely different from the tone or time-of-flight techniques, but is a direct translation of the same-named technique used in radar ranging systems
Children and divorce: a study of Divorce Court supervision orders
This research study was of the making and administration of Divorce Court Supervision Orders. Although established in England and Wales in 1958, there has been no detailed examination of supervision in domestic proceedings. In the 1979 period, when the population was obtained, 6,935 Divorce Court Supervision Orders were made. This figure has reduced to approximately 5,000 in 1985, with a total of 26,50C) ongoing orders.
The population consisted of 121 children in 62 family units. Supervision could be undertaken by both probation officers or social workers. A review was undertaken of the original intentions of Divorce Court Supervision Orders as conceived by the Royal Commission on Marriage and Divorce 1951-55, and any subsequent amendments by legislation. Particular emphasis is also given to changing aspects of family law which might affect provision for children the history of social work to children in divorce proceedings was also examined.
A detailed analysis was undertaken of descriptive material, on the place of children in divorce proceedings. This included research studies on the effects of divorce on children and any changes in the provision of services to parents and their children at the time of divorce proceedings. A full explanation is given of concepts such as conciliation.
The original theoretical framework, placed the study of Divorce Court Supervision orders, in the wider context of the social policy of divorce proceedings. Reference is made to principles of family law and the possible relevance of a Juvenile Justice framework to the Divorce Court. In addition, Weber's concept of legitimacy was applied to the examination of Divorce Court Supervision Orders.
The original research design, indicated the specific purposes of the research, which relate directly to the principles of a juvenile justice system. Details were given of the interview procedure, experience survey, identification of the validity and reliability considerations and the tests to be applied.
The findings of the research are outlined in two chapters. They concentrate on the history of the families concerned, the nature of the divorce process and the details of Welfare Report recommendations. Due to the absence of any study of the process of supervision, as opposed to limited studies on the content of Divorce Court Welfare Reports, one chapter describes in some depth, the process of supervision. The analysis uses a combination of statistical tests and case examples. The use of case examples can illustrate most effectively the nature of the supervision provided. A section of the final empirical chapter addresses validity questions, by examination of what organisations a supervising officer had contact with during their involvement with a family, and the degree of continued jurisdiction of the Divorce Court over the supervision undertaken.
A review of the main findings asks fundamental questions about the benevolence or control provided in domestic supervision. The final chapter places the present study, in the changing context of social work with children and their parents, involved in divorce proceedings. Child protectionism was identified as a fundamental principle, in spite of the last thirty years of reforms in family law.
In addition, the final chapter questions the desirability of continued confusion over better services to divorcing parents and their children and child-protectionist based interventions by social work agencies. Parallels are drawn between the present study and other aspects of family law involving social work agencies. Throughout the research study, it was emphasised that the present research is exploratory and where appropriate, future areas of appropriate research were indicated
Children and divorce: a study of Divorce Court supervision orders
This research study was of the making and administration of Divorce Court Supervision Orders. Although established in England and Wales in 1958, there has been no detailed examination of supervision in domestic proceedings. In the 1979 period, when the population was obtained, 6,935 Divorce Court Supervision Orders were made. This figure has reduced to approximately 5,000 in 1985, with a total of 26,50C) ongoing orders.
The population consisted of 121 children in 62 family units. Supervision could be undertaken by both probation officers or social workers. A review was undertaken of the original intentions of Divorce Court Supervision Orders as conceived by the Royal Commission on Marriage and Divorce 1951-55, and any subsequent amendments by legislation. Particular emphasis is also given to changing aspects of family law which might affect provision for children the history of social work to children in divorce proceedings was also examined.
A detailed analysis was undertaken of descriptive material, on the place of children in divorce proceedings. This included research studies on the effects of divorce on children and any changes in the provision of services to parents and their children at the time of divorce proceedings. A full explanation is given of concepts such as conciliation.
The original theoretical framework, placed the study of Divorce Court Supervision orders, in the wider context of the social policy of divorce proceedings. Reference is made to principles of family law and the possible relevance of a Juvenile Justice framework to the Divorce Court. In addition, Weber's concept of legitimacy was applied to the examination of Divorce Court Supervision Orders.
The original research design, indicated the specific purposes of the research, which relate directly to the principles of a juvenile justice system. Details were given of the interview procedure, experience survey, identification of the validity and reliability considerations and the tests to be applied.
The findings of the research are outlined in two chapters. They concentrate on the history of the families concerned, the nature of the divorce process and the details of Welfare Report recommendations. Due to the absence of any study of the process of supervision, as opposed to limited studies on the content of Divorce Court Welfare Reports, one chapter describes in some depth, the process of supervision. The analysis uses a combination of statistical tests and case examples. The use of case examples can illustrate most effectively the nature of the supervision provided. A section of the final empirical chapter addresses validity questions, by examination of what organisations a supervising officer had contact with during their involvement with a family, and the degree of continued jurisdiction of the Divorce Court over the supervision undertaken.
A review of the main findings asks fundamental questions about the benevolence or control provided in domestic supervision. The final chapter places the present study, in the changing context of social work with children and their parents, involved in divorce proceedings. Child protectionism was identified as a fundamental principle, in spite of the last thirty years of reforms in family law.
In addition, the final chapter questions the desirability of continued confusion over better services to divorcing parents and their children and child-protectionist based interventions by social work agencies. Parallels are drawn between the present study and other aspects of family law involving social work agencies. Throughout the research study, it was emphasised that the present research is exploratory and where appropriate, future areas of appropriate research were indicated
Development of a Spinal Cord Injury Model using the Material Point Method
Spinal cord injury (SCI) is characterised by permanent loss of motor and sensory function. The primary damage from the initial mechanical insult is exacerbated by the secondary patho-physiological cascade. Research into neuroprotective interventions to preserve tissue and reduce the damage caused by the secondary injury is hampered, in part, due to a lack of understanding of the link between the biomechanics of the primary traumatic injury and the subsequent evolution of the secondary injury. Hence, there is a need to better understand the biomechanics of SCI, the distinct injury patterns produced, and how these affect the evolution of the secondary cascade.
Computational models using finite element methods (FEM) have been established as a useful tool for investigating SCI biomechanics. These may be used to obtain data that is difficult or impossible to capture through in vivo and in vitro experiments, in particular; stress and strain fields within the neural tissue. However, the complexity of these models is limited by difficulties. These include: problems coping with large deformations over short periods of time due to mesh tangling, difficulties in incorporating the fluid structure interactions, and scalability issues when attempting to make use of high performance computing facilities, utilising large numbers of processors.
This work has involved the creation of a computational spinal cord injury using the Material Point Method (MPM) and MPMICE (MPM for Implicit, Continuous Fluid, Eulerian), alternative computational methods that overcome these limitations. The model incorporates the neural spinal cord tissue, the dura mater, and the cerebrospinal fluid. This model has been validated against equivalent experimental and FEM results. MPM/MPMICE was found to be a viable alternative to FEM for modelling SCI computationally, with the potential to enable more complex and anatomically detailed models through the utilisation of increased parallel computation
Ten-year experience of retrievable inferior vena cava filters in a tertiary referral center
PURPOSE:A significant proportion of patients undergoing surgery have an increased incidence of acute pulmonary embolus (PE). We analyzed all patients who had a retrievable inferior vena cava (IVC) filter placed preoperatively for PE prophylaxis and investigated the long-term outcomes of the patients who did not have their filter removed.METHODS:Patients who underwent retrievable IVC filter insertion and attempted removal were identified from the radiology information systems database in a large tertiary referral university teaching hospital. Results of all clinical investigations (including computed tomography, magnetic resonance imaging, ultrasonography, and plain radiography) while the IVC filters were in situ were reviewed.RESULTS:In total, 393 retrievable IVC filters were inserted, 254 with the indication of preoperative thromboembolic prophylaxis. Recurrent PE was reported in five patients (1.9%) despite the IVC filter. Of the 254 retrievable filters inserted prior to surgery, an attempt at retrieval was made in 168 filters (66.1%). Successful retrieval at the first attempt occurred in 143 cases (85.1%), while 25 cases failed or were aborted (14.9%). No attempt at retrieval was made in 86 (33.9%) patients and a significant proportion of these patients had undergone cancer surgery (P < 0.0107). In those patients where there was no attempt at retrieval, there was an association between cancer surgery and a shorter absolute survival time (P < 0.0001).CONCLUSION:The majority of attempted filter retrievals were successful, and a proportion of nonretrieved IVC filters are accounted for in patients who underwent cancer surgery and ultimately died with the filter in situ. A departmental protocol is recommended to ensure the filter is removed where appropriate and possible
Book Reviews
Anchor of the Soul (a documentary video about black life in Maine) produced by Shoshana Hoose and Karen Odlin; Headstrong: The Biography of Amy Morris Bradley, 1823-1904, A Life of Nobel Usefulness by Diane Cobb Cashman; Fifty year of Fortitude: The Maritime Career of Captain Jotham Blaisdell of Kennebunk, Maine 1820-1860 by Kendrick Price Daggett; The Civil War Letters of Capt. John Franklin Godfrey edited by Candace Sawyer and Laura Orcut; Dearest Father: The Civil War Letters of Lt. Frank Dickerson, A Son of Belfast, Maine edited by Draper Hunt; Dear Friend Anna: The Civil War Letters of a Common Soldier from Maine edited by Beverly Hayes Kallgren and James L. Crouthamel; William E. Barry\u27s Sketch of an Old River: Shipbuilding on the Kennebunk edited by Joyce Butler; Maine Politics and Government by Kenneth T. Palmer, G. Thomas Taylor and Marcus A. Librizzi
Classical, novel and atypical isoforms of PKC stimulate ANF- and TRE/AP-1-regulated-promoter activity in ventricular cardiomyocytes
Cultured neonatal rat ventricular myocytes were co-transfected with expression plasmids encoding protein kinase C (PKC) isoforms from each of the PKC subfamilies (classical PKC-α, novel PKC-ε or atypical PKC-ξ) together with an atrial natriuretic factor (ANF) reporter plasmid. Each PKC had been rendered constitutively active by a single Ala→Glu mutation or a small deletion in the inhibitory pseudosubstrate site. cPKC-α, nPKC-ε or aPKC-ξ expression plasmids each stimulated ANF-promoter activity and expression of a reporter gene under the control of a 12-O-tetradecanoylphorbol 13-acetate-response element (TRE). Upregulation of the ANF promoter is characteristic of the hypertrophic response in the heart ventricle and a TRE is present in the ANF promoter. Thus all subfamilies of PKC may have the potential to contribute to hypertrophic response in cardiomyocytes
Lumbar spine radiographic features and demographic, clinical, and radiographic knee, hip and hand osteoarthritis: The Johnston County Osteoarthritis Project
Objective—1) To determine the prevalence of lumbar spine individual radiographic features (IRF) of disc space narrowing (DSN), osteophytes (OST) and facet joint osteoarthritis (FOA). 2) To describe the frequencies of demographic, clinic and radiographic knee, hip and hand osteoarthritis (OA) across lumbar spine IRF. 3) To determine factors associated with lumbar spine IRF. Methods—A cross-sectional study of 840 participants enrolled in the Johnston County OA Project (2003-4). Sample-based prevalence estimates were generated for each lumbar spine IRF. Associations between lumbar spine IRF and demographic, clinical and peripheral joint OA were determined with logistic regression models. Results—Sample-based prevalence estimates were similar for DSN (57.6%) and FOA (57.9%) but higher for OST (88.1%) with significant differences across race and gender. Hand and knee OA frequencies increased across IRF whereas the effect was absent for hip OA. African Americans had lower odds of FOA (adjusted odds ratio [aOR]=0.45 (95% CI 0.32, 0.62)) while there was no racial association with DSN and OST. Low back symptoms were associated with DSN (aOR=1.37 (95% CI 1.04, 1.80)) but not OST or FOA. Knee OA was associated with OST (aOR=1.62 (95% CI 1.16, 2.27)) and FOA (aOR=1.69 (95% CI 1.15, 2.49)) but not DSN. Hand OA was associated with FOA (aOR=1.67 (95% CI 1.20, 2.28)) but not with DSN or OST. No associations were found with hip OA. Conclusion—These findings underscore the importance of analyzing lumbar spine IRF separately as the associations with demographic, clinic and radiographic knee, hip and hand OA differ widely
Physiological responses of Oxyrrhis marina to a diet of virally infected Emiliania huxleyi
The coccolithophore Emiliania huxleyi forms some of the largest phytoplankton blooms in the ocean. The rapid demise of these blooms has been linked to viral infections. E. huxleyi abundance, distribution, and nutritional status make them an important food source for the heterotrophic protists which are classified as microzooplankton in marine food webs. In this study we investigated the fate of E. huxleyi (CCMP 374) infected with virus strain EhV-86 in a simple predator-prey interaction. The ingestion rates of Oxyrrhis marina were significantly lower (between 26.9 and 50.4%) when fed virus-infected E. huxleyi cells compared to non-infected cells. Despite the lower ingestion rates, O. marina showed significantly higher growth rates (between 30 and 91.3%) when fed infected E. huxleyi cells, suggesting higher nutritional value and/or greater assimilation of infected E. huxleyi cells. No significant differences were found in O. marina cell volumes or fatty acids profiles. These results show that virally infected E. huxleyi support higher growth rates of single celled heterotrophs and in addition to the “viral shunt” hypothesis, viral infections may also divert more carbon to mesozooplankton grazers
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