Parameter identification for an abstract Cauchy problem by quasilinearization

A parameter identification problem is considered in the context of a linear abstract Cauchy problem with a parameter-dependent evolution operator. Conditions are investigated under which the gradient of the state with respect to a parameter possesses smoothness properties which lead to local convergence of an estimation algorithm based on quasi-linearization. Numerical results are presented concerning estimation of unknown parameters in delay-differential equations

Geologic factors in the evaluation of water pollution potential at mountain dwelling sites

December, 1973.Bibliography: pages [133]-135.In order to establish the relationship between the geologic setting and the occurrence of water pollution in mountain home developments containing individual sewage disposal systems, three areas in Colorado's Front Range were studied. Two of the areas were known to have biological contamination as confirmed by microbiological tests. Also, each area had adequate rock exposures to allow for detailed geologic study, the absence of thick soil profiles above bedrock and current development for mountain home location. In addition, each of the selected study areas differed in geologic setting, age of development and home density in the development. The extent of water pollution was established by a program of well and surface water testing for total coliform. Fecal coliform and inorganic contaminants were tested in selected wells. Detailed geologic maps were made of each area to locate features such as dikes or shear zones which might act as either barriers or conduits to ground water movement. Slope maps were prepared for the area by computer plots of digitized data of elevations taken from U.S. Geological Survey topographic maps. Determination of the water table profile and extent of alluvial fill in valley bottoms was accomplished using driller's well logs for each well in the area. In addition, soils were tested to determine their effective grain size, a joint and foliation study was conducted to determine the direction of pollutant travel should effluent enter these openings, driller's well logs were used to establish depth of soils and depth of weathering in bedrock and data from county health records were used to establish soil percolation rates. Data were compiled in the form of overlays on base maps of the areas involved. A topographic map with the geologic overlay was used in conjunction with various combinations of the field derivative overlays to indicate the pollution potential for specific areas. The overlays used in this procedure were compiled from. the following parameters: 1) slope, 2) depth of soil, 3) depth of intensely weathered bedrock, 4) local water table profile, and 5) soil percolation rates. These overlays indicated that the Glen Haven area is unsuitable for soil absorption sewage systems because of steep slopes, soil depth and depth of the water table. Most of the Tall Timbers area was indicated as unsuitable for soil absorption systems because of slope, soil depth and local geology. The Crescent Park area was categorized as safe (in part) for soil absorption systems, however, local areas within the subdivision were categorized as hazardous. From the results it was suggested that a procedure such as the one used in this study could be used for each subdivision proposed in the mountainous regions of Colorado. Thus more effective use of mountainous areas might be passable while maintaining a low probability of ground water contamination. Areas within each proposed subdivision would be classified as safe, hazardous, or unsuitable for soil absorption sewage systems. Unsuitable areas could be used as parks or greenbelts, hazardous areas would have low population densities and safe areas would be allowed to have higher population densities as long as other factors were favorable. In addition, procedures such as the one used in this investigation could be used to indicate mountain areas which should require a municipal sewage disposal system before development to ensure that the ground water system was not polluted.Supported by the Colorado Water Quality Control Commission and the United States Department of Interior, Office of Water Resources Research, no.87-194-2. (s) 14-01-001-1882

On the Evolution Equation for Magnetic Geodesics

In this paper we prove the existence of long time solutions for the parabolic equation for closed magnetic geodesics.Comment: In this paper we prove the existence of long time solutions for the parabolic equation for closed magnetic geodesic

Participant Blinding and Gastrointestinal Illness in a Randomized, Controlled Trial of an In-Home Drinking Water Intervention

We conducted a randomized, triple-blinded home drinking water intervention trial to determine if a large study could be undertaken while successfully blinding participants. Households were randomized 50:50 to use externally identical active or sham treatment devices. We measured the effectiveness of blinding of participants by using a published blinding index in which values >0.5 indicate successful blinding. The principal health outcome measured was “highly credible gastrointestinal illness” (HCGI). Participants (n=236) from 77 households were successfully blinded to their treatment assignment. At the end of the study, the blinding index was 0.64 (95% confidence interval 0.51-0.78). There were 103 episodes of HCGI during 10,790 person-days at risk in the sham group and 82 episodes during 11,380 person-days at risk in the active treatment group. The incidence rate ratio of disease (adjusted for the clustered sampling) was 1.32 (95% CI 0.75, 2.33) and the attributable risk was 0.24 (95% CI -0.33, 0.57). These data confirm that participants can be successfully blinded to treatment group assignment during a randomized trial of an in-home drinking water intervention

Patient-derived Organoid Pharmacotyping is a Clinically Tractable Strategy for Precision Medicine in Pancreatic Cancer

Objective: PDAC patients who undergo surgical resection and receive effective chemotherapy have the best chance of long-term survival. Unfortunately, we lack predictive biomarkers to guide optimal systemic treatment. Ex-vivo generation of PDO for pharmacotyping may serve as predictive biomarkers in PDAC. The goal of the current study was to demonstrate the clinical feasibility of a PDO-guided precision medicine framework of care. Methods: PDO cultures were established from surgical specimens and endoscopic biopsies, expanded in Matrigel, and used for high-throughput drug testing (pharmacotyping). Efficacy of standard-of-care chemotherapeutics was assessed by measuring cell viability after drug exposure. Results: A framework for rapid pharmacotyping of PDOs was established across a multi-institutional consortium of academic medical centers. Specimens obtained remotely and shipped to a central biorepository maintain viability and allowed generation of PDOs with 77% success. Early cultures maintain the clonal heterogeneity seen in PDAC with similar phenotypes (cystic-solid). Late cultures exhibit a dominant clone with a pharmacotyping profile similar to early passages. The biomass required for accurate pharmacotyping can be minimized by leveraging a high-throughput technology. Twenty-nine cultures were pharmacotyped to derive a population distribution of chemotherapeutic sensitivity at our center. Pharmacotyping rapidly-expanded PDOs was completed in a median of 48 (range 18-102) days. Conclusions: Rapid development of PDOs from patients undergoing surgery for PDAC is eminently feasible within the perioperative recovery period, enabling the potential for pharmacotyping to guide postoperative adjuvant chemotherapeutic selection. Studies validating PDOs as a promising predictive biomarker are ongoing.Peer reviewe

Process evaluation of a peer-led antenatal breastfeeding class for fathers: perceptions of facilitators and participants

Background: The Parent Infant Feeding Initiative (PIFI) was a factorial, randomised controlled trial that aimed to prolong exclusive breastfeeding by targeting expecting fathers. One of the intervention strategies evaluated was a father-focused breastfeeding class facilitated by a male peer facilitator. The aim of this mixed-methods descriptive study was to 1) evaluate the feedback provided from participants of the class and 2) explore the motivations and experiences of volunteer male peer facilitators trained to deliver the class. Methods: Father-focused breastfeeding antenatal (FFAB) classes were conducted in six Western Australian hospitals between August 2015 and December 2016. Following each peer facilitated FFAB class, expecting father participants completed an evaluation form to assess their satisfaction with the format, facilitation and content, in addition to whether their expectations and confidence to manage breastfeeding problems had changed. Feedback to open-ended questions was analysed using content analysis to identify learnings and suggestions for improvements. At the completion of PIFI, individual telephone interviews were undertaken with 14 peer facilitators to gain insight into their motivations for volunteering and experiences of conducting the classes. Transcripts from interviews were analysed using Braun and Clarke’s six phases for thematic analysis. Results: Participant evaluation forms were completed by 678 of the 697 father participants (98%). Overall satisfaction with class format, facilitation and content was high with 90% or more of fathers either strongly agreeing or agreeing with each positively-phrased evaluation item. Class participants enjoyed interacting with other fathers, appreciated validation of their role, were not always aware of the importance of breastfeeding or potential difficulties, valued the anticipatory guidance around what to expect in the early weeks of parenting and appreciated learning practical breastfeeding support strategies. Peer facilitators indicated they felt well prepared and supported to conduct FFAB classes. Analysis of interview transcripts revealed common experiences of the peer facilitators incorporating four themes: ‘Highlights of being a facilitator’, ‘Challenges’, ‘Mourning the project completion’ and ‘Satisfaction with training and support’. Conclusion: Father-focused breastfeeding classes supported by volunteer male peer facilitators are a feasible and acceptable way of engaging fathers as breastfeeding supporters. Trial registration: ACTRN12614000605695. Registered 6 June 2014

Communications Biophysics

Contains reports on nine research projects split into four sections.National Institutes of Health (Grant 5 PO1 NS13126)National Institutes of Health (Grant 5 KO4 NS00113)National Institutes of Health (Training Grant 5 T32 NS07047)National Institutes of Health (Training Grant 1 T32 NS07099)National Science Foundation (Grant BNS77-16861)National Institutes of Health (Grant 5 ROI NS10916)National Institutes of Health (Grant 5 RO1 NS12846)National Science Foundation (Grant BNS77-21751)National Institutes of Health (Grant 1 RO1 NS14092)Edith E. Sturgis FoundationHealth Sciences FundNational Institutes of Health (Grant 2 R01 NS11680)National Institutes of Health (Fellowship 5 F32 NS05327)National Institutes of Health (Grant 2 ROI NS11080)National Institutes of Health (Training Grant 5 T32 GM07301