Continuous measurement of a non-Markovian open quantum system

Continuous quantum measurement is the backbone of various methods in quantum control, quantum metrology, and quantum information. Here, we present a generalized formulation of dispersive measurement of a complex quantum systems. We describe the complex system as an open quantum system that is strongly coupled to a non-Markovian environment, enabling the treatment of a broad variety of natural or engineered complex systems. The system is monitored via a probe resonator coupled to a broadband (Markovian) reservoir. Based on this model, we derive a formalism of stochastic hierarchy equations of motion describing the decoherence dynamics of the system conditioned on the measurement record. Furthermore, we demonstrate a spectroscopy method based on weak quantum measurement to reveal the non-Markovian nature of the environment, which we term weak spectroscopy.

Reproducibility, fidelity, and discriminant validity of mRNA amplification for microarray analysis from primary hematopoietic cells

Analysis of gene expression in clinical samples poses special challenges, including limited RNA availability and poor RNA quality. Quantitative information regarding reliability of RNA amplification methodologies applied to primary cells and representativeness of resulting gene expression profiles is limited. We evaluated four protocols for RNA amplification from peripheral blood mononuclear cells. Results obtained with 100 ng or 10 ng of RNA amplified using two rounds of cDNA synthesis and in vitro transcription were compared with control 2.5-microg RNA samples processed using a single round of in vitro transcription. Samples were hybridized to Affymetrix HG-U133A arrays. Considerable differences in results were obtained with different protocols. The optimal protocol resulted in highly reproducible gene expression profiles from amplified samples (r = 0.98) and good correlation between amplified and control samples (r = 0.94). Using the optimal protocol dissimilarities of gene expression between mononuclear cells from a normal individual and a patient with myelodysplastic syndrome were primarily maintained after amplification compared with controls. We conclude that small variations in methodology introduce considerable distortion of gene expression profiles obtained after RNA amplification from clinical samples and too strong a focus on a very small number of genes picked from an array analysis could be unduly influenced by seemingly acceptable methodologies. However, it is possible to obtain reproducible and representative results using optimized protocols.

Prospective, randomized evaluation of the efficacy of fibrin sealant as a topical hemostatic agent at the cannulation site in neonates undergoing extracorporeal membrane oxygenation

BACKGROUND

The topical hemostatic effect of fibrin sealant that has been solvent/detergent treated and plasminogen depleted was evaluated in a multicenter prospective, randomized controlled study at the cannulation site wound of infants undergoing extracorporeal membrane oxygenation (ECMO).

METHODS

The test group received standard cauterization and Fibrin sealant, while the control group was given cauterization alone to control hemostasis at this site. Efficacy data were available on 173 randomized study subjects of whom 149 met study entry criteria. All were managed according to standard ECMO practice.

RESULTS

Fibrin sealant reduced the risk of bleeding, was associated with less shed blood, and was associated with shorter duration of hemorrhage. Further, control infants showed an increased bleeding risk with less depressed fibrinogen levels and prothrombin time elevations >18 seconds prior to ECMO.

CONCLUSION

Fibrin sealant is useful as a topical hemostatic agent in patients with coagulopathy not responding to standard surgical techniques.

10 years of pediatric liver transplantation

PURPOSE

Pediatric liver transplantation is an accepted therapy for end-stage liver disease, but little long-term data exist.

METHODS

From October 1984 to October 1994, 202 patients underwent a total of 225 liver transplantations. There were 98 boys and 104 girls, the average age was 5.1 +/- 4.9 (range, 0.2 to 19.1) years. Thirty (16%) were under 1 year of age. The diseases that required transplantation included biliary atresia (BA) (45%), metabolic liver disease (MLD) (9.9%), acute hepatic failure (6.9%), and Alagille's syndrome (AS) (5.4%). Originally the immunosuppression was cyclosporine- and steroid-based; the later regimens also included azathioprine and antilymphocyte preparations. All reported survival rates were derived from life-table analysis.

RESULTS

The patient survival rates at 1, 5, and 10 years were 76%, 70%, and 61%; the retransplantation rate was 11%. The respective graft survival rates were 71%, 63%, and 59%. There were 60 deaths; 48 (81%) occurred in the first year. These first-year deaths were from sepsis (20; 42%), central nervous system problems (5; 11%), intraoperative complications (4; 8%), lymphoproliferative disease (LPD) (2; 4%), rejection (2; 4%), primary nonfunction (2; 4%), and miscellaneous other causes (7; 15%). There were 12 deaths after the first year, from LPD (3; 25%), sepsis (1; 8%), rejection (2; 18%), cancer (1; 9%), secondary hepatic failure (1; 9%), cerebral vascular accident (1; 9%), or pre- or postoperative complications (3; 25%). Compared with the overall survival rate, patients with MLD had a better chance of survival (83%; P <.012) than did those with AS (45%; P < .001). The 5- and 10-year survival rates for patients with BA were 61% and 58%. Over the past 2 years, the survival rate has increased (87% v 72%; P < .05) as early septic deaths have decreased (from 2.6 to 1.0 per year).

CONCLUSION

Liver transplantation is effective treatment for end-stage liver disease. Decreasing the number of early septic deaths has improved the chance of survival, and better diagnosis and treatment of LPD would improve the late survival rate.

Childhood immunization, homoeopathy and community nurses

The way for community nurse practitioners to promote medical childhood immunization to parents, is for them to become fully conversant with both alternative and traditional medical approaches to this issue. A brief overview of homoeopathy and its approaches to immunization is outlined highlighting the current debate for and against anti-medical and medical immunization. Arguments are put forward supporting medical immunization and the challenges this presents for nurses practitioners.

Congenital diaphragmatic hernia. Stabilization and repair on ECMO

Availability of extracorporeal membrane oxygenation (ECMO) support and the potential advantages of delayed repair of congenital diaphragmatic hernia (CDH) have led several centers to delay CDH repair, using ECMO support if necessary. This study reviews the combined experience of five ECMO centers with infants who underwent stabilization with ECMO and repair of CDH while still on ECMO. All infants were symptomatic at birth, with a mean arterial oxygen pressure (PaO2) of 34 mmHg on institution of bypass despite maximal ventilatory support. A total of 42 infants were repaired on ECMO, with 18 (43%) surviving. Seven infants had total absence of the diaphragm, and 28 required a prosthetic patch to close the defect. Only five infants ever achieved a best postductal PaO2 over 100 mmHg before institution of ECMO. Prematurity was a significant risk factor, with no infants younger than 37 weeks of age surviving. Significant hemorrhage on bypass was also a hallmark of a poor outcome, with 10 of the 24 nonsurvivors requiring five thoracotomies and six laparotomies to control bleeding, whereas only one survivor required a thoracotomy to control bleeding. In follow-up, nine of the 18 survivors (50%) have developed recurrent herniation and seven (43%) have significant gastroesophageal reflux. Importantly, five of the 18 survivors were in the extremely high-risk group who never achieved a PaO2 over 100 mmHg or an arterial carbon dioxide pressure (PaCO2) less than 40 mmHg before the institution of ECMO. In conclusion, preoperative stabilization with ECMO and repair on bypass may allow some high-risk infants to survive. Surviving infants will require long-term follow-up because many will require secondary operations.

Child immunisation levels in Sydney's Western Metropolitan Region: parental attitudes and nurses' roles

Research was undertaken to examine childhood immunisation uptake rates, parental attitudes towards immunisation and immunisation services and parents' perceptions of health workers' (especially nurses') contribution to immunisation in the Western Metropolitan Region of Sydney, NSW. After a pilot study a questionnaire was distributed by teachers to a random sample of 450 parents of kindergarten children living in the Region. Data revealed an 84% childhood immunisation rate for all scheduled immunisations up to five years with a partial immunisation rate of 10% (6% did not answer or had gaps in immunisation information). The most significant factors associated with partial immunisation were found to be the socioeconomic and educational status of the children's fathers and itinerancy. Parents of partially immunised children were significantly more likely than parents of totally immunised children to consider that serious side-effects to immunisation do occur. The research also found that parents have a knowledge deficit about the seriousness of measles; that immunisation services in the Region have significant deficiencies and that nurses have a low profile and poor image in the provision of those services. As Early Childhood nurses were considered by parents as providing the most appropriate immunisation nursing service, their further involvement in promoting and extending services is recommended.

Cellular basis for limitation of poplar leaf growth by water deficit

During the summers of 1986 and 1987, stem and leaf growth were measured on coppiced plants of Populus trichocarpa Torr. & A. Gray, P. deltoides Bartr. ex Marsh, and P. trichocarpa x deltoides growing in the field in Puyallup, WA. The trees were either irrigated periodically throughout the season, or grown without irrigation. In both treatments, stem volume at the end of the growing season was directly proportional to total leaf area in all three genotypes. The rate of individual leaf growth was reduced by lack of irrigation more in the parental species than in the hybrid. Only in the parental species did unirrigated trees have lower leaf water potentials (predawn and midday) than irrigated trees. However, stomatal conductances of all three genotypes were lower in unirrigated trees than in irrigated trees. Osmotic potentials of growing leaves of all three genotypes were also lower in unirrigated trees than in irrigated trees. As a consequence, turgor of growing leaves was as great in unirrigated trees as in irrigated trees, which indicates that turgor differences cannot explain the lower rates of leaf growth in the unirrigated trees. However, cell wall extensibility of leaves was lower in unirrigated trees than in irrigated trees, and the difference was greater in the parental species than in the hybrid. Unlike its effect on leaf area growth, irrigation increased stem volume growth of the hybrid and the parental species by a similar amount (12-16%).

Mental health and satisfaction among tax officers

This study assessed the mental well-being and job satisfaction of a random sample of 318 tax officers in England, Scotland, Wales and Northern Ireland. It was found that tax officers were less satisfied with their jobs, and showed signs of mental stress in contrast with other normative groups. Using multivariate analysis, it was found that 'autocratic management style' was a strong predictor of job dissatisfaction, while 'qualitative and quantitative work overload' was the major source of lack of mental well-being.