Kavraki, Lydia, Svestka, Petr, Latombe, Jean-Claude, Overmars, Mark; Probabilistic Roadmaps for Path Planning in High-Dimensional Configuration Spaces: A new motion planning method for robots in static workspaces is presented. This method proceeds according to two phases: a learning phase and a query phase. In the learning phase, a probabilistic roadmap is constructed and stored as a graph whose nodes correspond to collision-free configurations and edges to feasible paths between these configurations. These paths are computed using a simple and fast local planner. In the query phase, any given start and goal configurations of the robot are connected to two nodes of the roadmap; the roadmap is then searched for a path joining these two nodes. The method is general and easy to implement. It can be applied to virtually any type of holonomic robot. It requires selecting certain parameters (e.g., the duration of the learning phase) whose values depend on the considered scenes, that is the robots and their workspaces. But these values turn out to be relatively easy to choose. Increased efficiency can also be achieved by tailoring some components of the method (e.g., the local planner) to the considered robots. In this paper the method is applied to planar articulated robots with many degrees of freedom. Experimental results show that path planning can be done in a fraction of a second on a contemporary workstation (approximately 150 MIPS), after learning for relatively short periods of time (a few dozen seconds). [Text] (0.61)
Zhang, Ming, Kavraki, Lydia E.; Computing and Updating Molecular Conformations Using the Atomgroup Local Frames Method: Efficiently maintaining molecular conformations is important for molecular modeling and protein engineering. This paper reviews the widely used simple rotations scheme, simple local frames method, and introduces a new atomgroup local frames method for maintaining the molecular conformation changes due to the changes of torsional angles. The simple rotations scheme applies a sequence of rotations to update all atom positions. The order of the updates is important and some bookkeeping of the atom positions is necessary. Numeric errors can accumulate as rotations around the bonds are repeated. The simple local frames method builds local frames at the bonds, and relational matrices between parents and children frames are constructed. The atom positions are computed by chaining series of such matrices. No bookkeeping is necessary and numeric errors do not accumulate upon rotations. Multiple local frames are needed at a bond if it has more than one child. This paper introduces a new atomgroup local frames method to efficiently maintain molecular conformations. A single local frame is attached to each atomgroup. Bookkeeping is not necessary and numeric errors do not accumulate upon rotations. This method also provides lazy evaluations for atom positions. Thus, the conformational maintenance cost is greatly reduced, especially when many conformations are generated and updated such as in a minimization process. [Text] [View with Perseus links] (0.61)
Kavraki, Lydia E.; Random Networks in Configuration Space for Fast Path Planning: In the main part of this dissertation we present a new path planning method which computes collision-free paths for robots of virtually any type moving among stationary obstacles. This method proceeds according to two phases: a preprocessing phase and a query phase. In the preprocessing phase, a probabilistic network is constructed and stored as a graph whose nodes correspond to collision-free configurations and edges to feasible paths between these configurations. In the query phase, any given start and goal configurations of the robot are connected to two nodes of the network; the network is then searched for a path joining these two nodes. We apply our method to articulated robots with many degrees of freedom. Experimental results show that path planning can be done in a fraction of a second on a contemporary workstation ($\approx$ 150 MIPS), after relatively short preprocessing times (a few dozen to a few hundred seconds). In the second part of this dissertation, we present a new method that uses the the Fast Fourier Transform to compute the obstacle map required by certain path planning algorithms. In the final part of this dissertation, we consider a problem from assembly planning. In assembly planning we are interested in generating feasible sequences of motions that construct a mechanical product from its individual parts. We prove that the monotone assembly partitioning problem in the plane is NP-complete. [Text] (0.53)
Schwartz, Lydia.; Nonsense /--by Lydia Schwartz.: Thesis (M.F.A.)--University of North Carolina at Greensboro, 1975., Bibliography: leaf 18. [Text] (3.74)
Lin, Ling-chia Lydia Yeh.; Effects of uniform magnetic fields on the bioelectric response of the alga NI?²iI?²tI?²eI?²lI?²lI?²aI?² cI?²lI?²aI?²vI?²aI?²tI?²aI?² ;--a thesis [i.e. a dissertation] /--by Ling-chia Lydia Yeh Lin.: Thesis--Clarkson College of Technology, 1976., Includes bibliographical references (p. 105-112) and abstract. [Text] (3.54)
Wolfkill, Lydia Kime; The rise and growth of home economics :--and the character of students attracted to its courses /--by Lydia Kime Wolfkill.: Thesis--University of Nebraska., Bibliography: leaves 93-96. [Text] (3.54)
Fehm, Lydia Birgit; Unerwunschte Gedanken bei Angststorungen, alternative/translated: Diagnostik und experimentelle Befunde: Technische Universitat Dresden, Mathematik und Naturwissenschaften, Psychologie, Institut fur Klinische Psychologie; (in German) Die vorliegende Arbeit beschaftigt sich mit der Diagnostik unerwunschter Gedanken sowie der Spezifitat von Gedankenunterdruckung bei phobischen Patienten. Zwei Fragebogenverfahren zum Thema Sorgen sowie ein Instrument zur Erfassung von Strategien im Umgang mit intrusiven Gedanken wurden bezuglich der Gutekriterien der deutschen Ubersetzung in einer klinischen Stichprobe evaluiert. Dabei handelt es sich um den Worry Domains Questionnaire (WDQ), der Sorgeninhalte erhebt, den Penn State Worry Questionnaire (PSWQ), der die Intensitat von Sorgen erfasst, und den Thought Control Questionnaire (TCQ) zur Erfassung der Gedankenkontrollstrategien. Die Verfahren wurden bei 440 Psychotherapie-Patienten zu drei Messzeitpunkten eingesetzt. Hinsichtlich der inneren Konsistenz und der Retest-Reliabilitat ergeben sich fur alle Instrumente zufriedenstellende bis gute Kennwerte. Die Validitat ist nur fur den PSWQ als gut zu bezeichnen. Beim WDQ zeigen sich Probleme hinsichtlich der Trennung von Sorgen und sozialer Angstlichkeit, wahrend der TCQ wohl eher Aspekte allgemeiner Psychopathologie als spezifische Strategien erfasst. Eine zweite Studie befasste sich mit intentionaler Gedankenunterdruckung. Die paradoxen Effekte dieser Bemuhungen wurden wiederholt mit psychischen Storungen, vor allem mit Angststorungen, in Verbindung gebracht. Dabei ist ein wichtiges Thema, ob die Gedankenkontrollfahigkeit nur fur storungsspezifische Inhalte oder generell beeintrachtigt ist. Die vorliegende Studie verglich Patienten mit Agoraphobie und Patienten mit Sozialphobie mit einer gesunden Kontrollgruppe. Alle Personen mussten Gedanken an ein neutrales Kontrollthema sowie zwei storungsspezifische Themen unterdrucken. Es zeigte sich ein storungsspezifischer Effekt bei den Agoraphobikern. Sozialphobiker scheinen hingegen ein generelles Defizit ihrer mentalen Kontrolle aufzuweisen. Zusatzlich erwies sich soziale Angstlickeit innerhalb einer Reihe psychopathologischer Variablen als starkster Pradikator fur Schwierigkeiten bei der Gedankenunterdruckung. Ingesamt weisen einige Ergebnisse dieser Arbeit darauf hin, dass Gedankenunterdruckung ein wichtiges Merkmal der Sozialphobie sein konnte., The work conducted aimed at evaluating instruments investigating unwanted thoughts as well as determining the specifity of thought suppression in phobia. German translations of two questionnaires measuring worry as well as an instrument, measuring strategies used in dealing with unwanted thoughts, were evaluated in a clinical sample. We used the Worry Domains Questionnaire (WDQ), measuring contents of worry, the Penn State Worry Questionnaire (PSWQ), measuring the intensity of worry, and the Thought Control Questionnaire (TCQ), investigating strategies in thought control. The instruments were administered at three points in a sample of 440 patients receiving psychological treatment. Concerning internal consistency and retest-reliability all questionnaires showed acceptable to good results. Validity is only good concerning PSWQ. WDQ has problems in differentiating worry and social anxiety, where as TCQ seems to measure general psychopathology more than specific strategies. The second study investigated intended thought suppression. Its paradoxical effects have been linked to psychological disorders, namely anxiety disorders. One important issue is if thought suppression is impaired only for thoughts related to the disorder or if the ability for mental control is generally impaired in anxiety patients. This study compared groups of agoraphobics and social phobics with healthy controls. All subjects had to suppress a neutral topic and two topics related to the central fear of the two disorders. We found a rather specific deficit in thought suppression for the agoraphobics. Social phobics seem to be characterized by a general impairment of mental control. In addition, among several psychopathological variables, social anxiety proved to be the strongest predictor for problems with thought suppression. Taken together, there are several indicators that thought suppression may be an important feature of social phobia. [Text] (0.58)
McKenzie III, Harold Cantrell; Time and Concentration Relationships of Gentamicin in Serum and Bronchial Lavage Fluid of Horses Administered Gentamicin Intravenously and by Aerosol: Martin O. Furr DVM, Michael J. Murray DVM, MS, Lydia L. Donaldson VMD, PhD; (in English) This study was performed to compare the delivery of the antimicrobial gentamicin to the respiratory tract of adult horses following aerosol and intravenous administration. Nine adult horses were used in a crossover design. Aerosol administration of gentamicin was performed using a close fitting facemask and an ultrasonic nebulizer. Intravenous gentamicin was administered via a jugular venous catheter. Samples of pulmonary epithelial lining fluid were collected by bronchial lavage performed at 0.5, 4, 8 and 24 hours after gentamicin administration. All samples were analyzed for gentamicin concentration, and cytologic examination was performed on aliquots of bronchial lavage fluid from times 0.5, 8 and 24 hours. Comparisons were made using the Wilcoxon signed-rank test. The bronchial lavage fluid gentamicin concentration after aerosol administration was significantly greater (p<0.05) than after intravenous administration at 0.5, 4, and 8 hours. The bronchial lavage fluid total nucleated cell count increased significantly (p<0.05) from 0.5 to 24 hours following both routes of gentamicin administration, with the increase observed following aerosol administration being significantly greater (p<0.05) than that observed following intravenous administration. A significant increase in neutrophil count was detected between bronchial lavage fluid samples taken at 0.5 hours and 24 hours, regardless of route of gentamicin administration. We conclude that aerosol administration of gentamicin to the equine respiratory tract achieves bronchial lavage fluid gentamicin levels that are significantly higher than levels obtained following intravenous administration for at least the first 8 hours after administration, while inciting a mild inflammatory response. [Text] [View with Perseus links] (0.61)
Corley, Kevin Thomas Trent; Validation of a new method of determining cardiac output in neonatal foals: Dr. Lydia Donaldson, Dr. Martin O. Furr, Dr. G. Frederick Fregin; (in English) Hypotension is a common finding in hospitalized, critically ill neonatal foals. Hypotension may be a function of low cardiac output or increased cardiac output and decreased systemic vascular resistance. In the first instance, treatment would include fluids and/or inotropes and in the second, fluids and/or vasopressors. Therefore, cardiac output measurements are expected to help guide the treatment of hypotension associated with critical illness and/or anesthesia in neonatal foals. However, a practical and safe method of measuring cardiac output has not been described for the foal. Lithium dilution, a new method of cardiac output determination not requiring cardiac catheterization, has recently been reported in adult horses. We compared this method to thermodilution in isoflurane anesthetized, 30 to 42 hour old foals and found good agreement (mean bias 0.0474L/min; limits of agreement -3.03 to 3.12) between the two methods in a range of cardiac outputs from 5.4 to 20.4 liters/min. The lithium dilution technique is a practical and reliable method of measuring cardiac output in anesthetized neonatal foals, and warrants investigation in critically ill conscious foals. [Text] [View with Perseus links] (0.59)
Young, Byron Leslie; Treatment of Ischemic Equine Jejunum with Topical and Intraluminal Carolina Rinse: Mark V.Crisman, Nathaniel A. White II, Lydia L. Donaldson; (in English) TREATMENT OF ISCHEMIC EQUINE JEJUNUM WITH TOPICAL AND INTRALUMINAL CAROLINA RINSE Byron L. Young, DVM Abstract Carolina Rinse (CRS) has been shown to be effective in decreasing vascular permeability and neutrophil infiltration in reperfused equine small intestine. The objective of this study was to show that CRS applied topically and intraluminally could prevent immediate reperfusion injury after low flow ischemia or distention in the equine jejunum. Materials & Methods: Two groups of 5 horses were used to evaluate CRS treatment after low-flow ischemia (Group 1) and intraluminal distention (Group 2) of distal jejunum. Mesenteric blood flow, osmotic reflection coefficient (ORC), wet weight to dry weight ratios (WW/DW), and neutrophil accumulation in the serosa were measured. ORC is defined as the lymph protein concentration to plasma protein concentration ratio subtracted from one (1- Cl / Cp) at maximal lymph flow. The ORC from baseline values and at 60 minutes after initiating reperfusion was compared between Groups 1 and 2. Pair wise comparisons were made for mesenteric blood flow, tissue volume, neutrophil number, and WW/DW proximal control and CRS treated jejunal segments were made using a Mann Whitney U test (P< 0.05). Results: The mean ORC of bowel treated topically and intraluminally with CRS was similar to that recorded in normal bowel or ischemic intestine treated with CRS by arterial perfusion. The ORC after distention and decompression increased and was similar to that reported in untreated intestine. The WW/DW after both ischemia and distention increased compared to the proximal control segments. There was no difference in neutrophil number in either ischemic or distended intestine compared to the proximal control segments. Discussion: Carolina CRS was effective in preventing alterations in microvascular permeability during reperfusion afterischemia but not distention. Neutrophil migration curtailed in both groups suggesting that combined topical and intraluminal application of CRS to ischemic intestine may reduce the acute inflammatory responses during reperfusion thereby decreasing complications after ischemia or distention. [Text] [View with Perseus links] (0.34)