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Kinship-based methods of population assessment such as close-kin mark-recapture require accurate and efficient genotyping methods capable of resolving complex relationships among kin. Inference of such relationships can be difficult using biallelic loci due to the large number of markers required to obtain the necessary power. Sequencing-based microsatellite panels offer an efficient alternative, combining high polymorphism with efficient next-generation methods. Here we construct, optimize, and test one such panel for lake trout ( Salvelinus namaycush ) using a combination of previously-published loci adapted for sequencing and de novo loci mined from a genome assembly. We performed three rounds of primer optimization, yielding a final panel of 131 loci, followed by testing with two different levels of PCR multiplexing (all primers in one or two groups) and two different reaction volumes (5 and 10 μL). Our results showed that the use of the largest multiplex and smallest reaction volume did not substantially change results, allowing significant cost and time savings. To test panel accuracy, we used both a set of 153 known-origin samples from origins of management interest and a series of hatchery crosses representing nine families with parent-offspring, half-sibling, and largely-unrelated pairs. Our results indicate that sequencing-based microsatellite panels can efficiently and accurately provide the information required for a population genetics analyses including population assignment, calculation of between-population F ST , and kinship-based population estimation techniques. Such techniques are seeing increasing applications for a wide range of taxa; our findings should provide insight and guidance for the development of the necessary molecular resources., (© 2023 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)

Introduction: This study investigates whether student confidence could be improved through the use of simulated patient case-based scenarios., Materials and Methods: Students in their 4th and 5th year of undergraduate study completed an online e-portfolio workbook consisting of activities related to five simulated patient cases. Following completion of the relevant learning activities within the e-portfolio, students then viewed a tutor case presentation video and attended simulated clinic sessions to complete corresponding exercises involving 3D-printed teeth related to the case. Subsequently, students undertook online self-reflection and goal-setting activities to aid their development. An anonymous questionnaire was distributed to all participants to gain insight into the themes of student confidence and learning support. The Cronbach's Alpha coefficient was calculated for both sections of the student questionnaire. The values for "student confidence" and "learning support" were α = 0.91 and α = 0.87, respectively., Results: There was a total of 89 valid student responses to the questionnaire (65%). A Spearman's correlation of r s  = 0.50 (p < .001) suggests a tentative causative correlation between the learning support offered through the simulated patient cases and student confidence. There was a positive directional relationship between engagement with the learning support of the simulated patient cases and student confidence scores., Conclusion: Student confidence increased following the completion of simulated patient cases and students found the learning support offered beneficial to their development. This learning intervention has the potential to improve student self-efficacy, develop contextual competency and facilitate reflective practice. Simulated patient cases may be a useful precursor or adjunct to traditional patient clinics., (© 2022 The Authors. European Journal of Dental Education published by John Wiley & Sons Ltd.)

Introduction: The use of direct to patient (DTP) telemedicine for common acute conditions is widespread. It provides certain advantages over in-person visits, but has led to concerns about fragmentation of care. It is unknown whether use of DTP telemedicine decreases use of primary care services in a way that leads to missed preventive screenings and immunizations. Methods: Virtual urgent care (VUC) is a DTP telemedicine service to treat common acute conditions. All VUC encounters completed at an academic health system from July 2018 to December 2019 were evaluated and analyzed in 2020. Only patients established with primary care (at least one primary care visit in the same year as VUC encounter) were included. Specific preventive screenings (breast cancer, gonorrhea/chlamydia, and cervical cancer) and immunizations (tetanus and influenza) were characterized as up to date based on national guidelines. Chi-squares and multivariate logistic regressions were used to assess receipt of screenings and immunizations. Regressions included VUC and primary care utilization and demographic factors. Results: Patients evaluated ( N  = 1025) were mostly 25-50 years old (69.7%), women (81.8%), and white (74.9%). More than half (56.5%) had only used VUC once. In multivariate analyses, VUC utilization was not negatively associated with any of the preventive services evaluated, whereas primary care utilization was associated with receipt of both immunizations and gonorrhea/chlamydia screening. Conclusions: Higher VUC utilization is not negatively associated with receipt of preventive services, as long as a primary care relationship is established. VUC may provide a useful method of encouraging receipt of preventive services, especially for younger patients.

Background: Surgical quality improvement initiatives may impact sociodemographic groups differentially. The objective of this analysis was to assess the trajectory of surgical morbidity by race and age over time within a Regional Collaborative Quality Initiative., Study Design: Adults undergoing eligible general surgery procedures in South Carolina Surgical Quality Collaborative hospitals were analyzed for the presence of at least 1 of 22 morbidities between August 2015 and February 2020. Surgery-level multivariable logistic regression assessed the racial differences in morbidity over time, stratified by age group (18 to 64 years, 65 years and older), and adjusting for potential patient- and surgical-level confounders., Results: A total of 30,761 general surgery cases were analyzed, of which 28.4% were performed in Black patients. Mean morbidity rates were higher for Black patients than non-Black patients (8.5% vs 6.0%, p < 0.0001). After controlling for race and other confounders, a significant decrease in monthly mean morbidity through time was observed in each age group (odds ratio [95% CI]: age 18 to 64 years, 0.986 [0.981 to 0.990]; age 65 years and older, 0.991 [0.986 to 0.995]). Comparing morbidity rates from the first 4 months of the collaborative to the last 4 months reveals older Black patients had an absolute decrease in morbidity of 6.2% compared with 3.6% for older non-Black patients. Younger Black patients had an absolute decrease in morbidity of 4.7% compared with a 3.0% decrease for younger non-Black patients., Conclusions: Black patients had higher morbidity rates than non-Black patients even when controlling for confounders. The reasons for these disparities are not apparent. Morbidity improved over time in all patients with older Black patients seeing a larger absolute decrease in morbidity., (Copyright © 2022 by the American College of Surgeons. Published by Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: To evaluate "high-risk" opioid dispensing to adolescents, including daily morphine milligram equivalents (MME) above recommended amounts, the percentage of extended-release opioid prescriptions dispensed to opioid-naïve adolescents, and concurrent use of opioids and benzodiazepines, and to evaluate changes in those rates over time., Methods: Retrospective cohort study of one state's prescription drug monitoring program data (2010-2017), evaluating adolescents 12-18 years old dispensed opioid analgesic prescriptions. Outcomes of interest were the quarterly frequencies of the high-risk measures. We utilized generalized linear regression to determine whether the rate of the outcomes changed over time., Results: The quarterly percentage of adolescents ages 12-18 years old dispensed an opioid who received ≥90 daily MME declined from 4.1% in the first quarter (Q1) of 2010 to 3.4% in the final quarter (Q4) of 2017 (p < 0.0001). The frequency of adolescents dispensed ≥50 daily MME changed little over time. In 2010, the percentage of adolescents receiving an extended-release opioid who were opioid naïve was 60.7%, declining to 50.6% by Q4 of 2017 (p > 0.10 overall change 2010-2017). The percentage of adolescent opioid days overlapping with benzodiazepine days was 1.6% in Q1 of 2010, declining to 1.1% by Q4 of 2017 (p < 0.001)., Conclusions: Among persons 12-18 years old dispensed an opioid analgesic, receipt of ≥90 daily MME declined during the years 2010-2017, as did the percentage of adolescent opioid days that overlapped with benzodiazepines. More than half of the individuals who received extended-release opioid analgesics were identified as opioid naïve and, counter to guidelines, received products intended for opioid-tolerant individuals., (© 2021 John Wiley & Sons Ltd.)

Background: Surgical quality improvement efforts are challenging due to the multidisciplinary nature of care, difficulties obtaining reliable data, and variability in quality metrics. The objective of this analysis was to assess whether participation in a regional collaborative quality initiative was associated with decreased in-hospital surgical complication in South Carolina., Study Design: In-hospital surgical complication rates were determined using a statewide all-payer claims data set. Retrospective, univariate, and longitudinal multivariable analyses were performed and adjustments were made to account for aggregated hospital-level patient characteristics., Results: The analysis included 275,387 general surgery cases performed in South Carolina hospitals between January 2016 and December 2018. Eight hospitals involved in the South Carolina Surgical Quality Collaborative (SCSQC) performed 56,179 cases and 51 non-SCSQC hospitals performed 219,208 cases. Univariate analysis revealed SCSQC hospitals performed operations in older patients (p < 0.0001) and patients with higher mean Charlson Comorbidity Index scores (p < 0.0001). SCSQC hospitals had higher mean in-hospital surgical complication rates at the surgery level compared with non-SCSQC hospitals (8.3% vs 7.0%; p < 0.0001). However, in multivariable analyses, the rate ratio for in-hospital surgical complication in SCSQC hospitals was 0.994 (95% CI, 0.989 to 0.998; p = 0.008) per month compared with non-SCSQC hospitals. This suggests a 21.6% (95% CI, 7.2% to 39.6%) proportional decrease in the rate of in-hospital surgical complication during 3 years associated with participation in the regional collaborative quality initiative., Conclusions: Structured collaboration between facilities, reliable data abstraction support, timely data review, and active member participation resulted in outcomes improvements for participating hospitals compared with hospitals that did not participate in a regional collaborative quality initiative., (Published by Elsevier Inc.)

Background and Objectives: Despite published declines in opioid prescribing and dispensing to children in the past decade, in few studies have researchers evaluated all children in 1 state or examined changes in mean daily opioid dispensed. In this study, we evaluated changes in the rate of dispensed opioid analgesics and the mean daily opioid dispensed to persons 0 to 18 years old in 1 state over an 8-year period., Methods: We identified opioid analgesics dispensed to children 0 to 18 years old between 2010 and 2017 using South Carolina prescription drug monitoring program data. We used generalized linear regression analyses to examine changes over time in the following: (1) rate of dispensed opioid prescriptions and (2) mean daily morphine milligram equivalents (MMEs) per prescription., Results: From the first quarter of 2010 to the end of the fourth quarter of 2017, the quarterly rate of opioids dispensed decreased from 18.68 prescriptions per 1000 state residents to 12.03 per 1000 residents ( P < .0001). The largest declines were among the oldest individuals, such as the 41.2% decline among 18-year-olds. From 2010 through 2017, the mean daily MME dispensed declined by 7.6%, from 40.7 MMEs per day in 2010 to 37.6 MMEs per day in 2017 ( P < .0001), but the decrease was limited to children 0 to 9 years old., Conclusions: The rate of opioid analgesic prescriptions dispensed to children 0 to 18 years old in South Carolina declined by 35.6% over the years 2010-2017; however, the MME dispensed per day declined minimally, suggesting that more can be done to improve opioid prescribing and dispensing., Competing Interests: POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose., (Copyright © 2021 by the American Academy of Pediatrics.)

Timing of activity, especially for juvenile anadromous fishes undertaking long migrations can be critical for survival. River-resident larval sea lamprey metamorphose into juveniles and migrate from their larval stream habitats in fall through spring, but diel timing of this migratory behavior is not well understood. Diel activity was determined for newly metamorphosed sea lamprey using day/night net sampling and passive integrated transponder (PIT) telemetry in two natural streams and PIT telemetry in an artificial stream. Downstream migration was primarily nocturnal in all studies. All but one of 372 sea lamprey were captured during night sampling in the day/night net collections and all detections (N = 56) for the in-stream PIT telemetry occurred within a few hours after sunset. Most (81% of 48) tagged lamprey moved downstream during the first night following release and moved at speeds consistent with observed water velocities. During long-term observation of behavior in the artificial stream most sea lamprey movement occurred during the night with limited occurrence of movement during daylight hours. Understanding seasonal and diel timing of downstream migration behavior may allow more effective management of sea lamprey for both conservation and control., Competing Interests: The authors have declared that no competing interests exist.

Deciding where to reproduce is a major challenge for most animals. Many select habitats based upon cues of successful reproduction by conspecifics, such as the presence of offspring from past reproductive events. For example, some fishes select spawning habitat following odors released by juveniles whose rearing habitat overlaps with spawning habitat. However, juveniles may emigrate before adults begin to search for spawning habitat; hence, the efficacy of juvenile cues could be constrained by degradation or dissipation rates. In lake trout ( Salvelinus namaycush ), odors deposited by the previous year's offspring have been hypothesized to guide adults to spawning reefs. However, in most extant populations, lake trout fry emigrate from spawning reefs during the spring and adults spawn during the fall. Therefore, we postulated that the role of fry odors in guiding habitat selection might be constrained by the time between fry emigration and adult spawning. Time course chemical, physiological, and behavioral assays indicated that the odors deposited by fry likely degrade or dissipate before adults select spawning habitats. Furthermore, fry feces did not attract wild lake trout to constructed spawning reefs in Lake Huron. Taken together, our results indicate fry odors are unlikely to act as cues for lake trout searching for spawning reefs in populations whose juveniles emigrate before the spawning season, and underscore the importance of environmental constraints on social cues.

Rationale, Aims and Objectives: Develop a risk-stratification model that clusters primary care patients with similar co-morbidities and social determinants and ranks 'within-practice' clusters of complex patients based on likelihood of hospital and emergency department (ED) utilization., Methods: A retrospective cohort analysis was performed on 10 408 adults who received their primary care at the Medical University of South Carolina University Internal Medicine clinic. A two-part generalized linear regression model was used to fit a predictive model for ED and hospital utilization. Agglomerative hierarchical clustering was used to identify patient subgroups with similar co-morbidities., Results: Factors associated with increased risk of utilization included specific disease clusters {e.g. renal disease cluster [rate ratio, RR = 5.47; 95% confidence interval (CI; 4.54, 6.59) P < 0.0001]}, low clinic visit adherence [RR = 0.33; 95% CI (0.28, 0.39) P < 0.0001] and census measure of high poverty rate [RR = 1.20; 95% CI (1.11, 1.28) P < 0.0001]. In the cluster model, a stable group of four clusters remained regardless of the number of additional clusters forced into the model. Although the largest number of high-utilization patients (top 20%) was in the multiple chronic condition cluster (1110 out of 4728), the largest proportion of high-utilization patients was in the renal disease cluster (67%)., Conclusions: Risk stratification enhanced with disease clustering organizes a primary care population into groups of similarly complex patients so that care coordination efforts can be focused and value of care can be maximized., (© 2015 John Wiley & Sons, Ltd.)

We sought proof of concept of a Big Data Solution incorporating longitudinal structured and unstructured patient-level data from electronic health records (EHR) to predict graft loss (GL) and mortality. For a quality improvement initiative, GL and mortality prediction models were constructed using baseline and follow-up data (0-90 days posttransplant; structured and unstructured for 1-year models; data up to 1 year for 3-year models) on adult solitary kidney transplant recipients transplanted during 2007-2015 as follows: Model 1: United Network for Organ Sharing (UNOS) data; Model 2: UNOS & Transplant Database (Tx Database) data; Model 3: UNOS, Tx Database & EHR comorbidity data; and Model 4: UNOS, Tx Database, EHR data, Posttransplant trajectory data, and unstructured data. A 10% 3-year GL rate was observed among 891 patients (2007-2015). Layering of data sources improved model performance; Model 1: area under the curve (AUC), 0.66; (95% confidence interval [CI]: 0.60, 0.72); Model 2: AUC, 0.68; (95% CI: 0.61-0.74); Model 3: AUC, 0.72; (95% CI: 0.66-077); Model 4: AUC, 0.84, (95 % CI: 0.79-0.89). One-year GL (AUC, 0.87; Model 4) and 3-year mortality (AUC, 0.84; Model 4) models performed similarly. A Big Data approach significantly adds efficacy to GL and mortality prediction models and is EHR deployable to optimize outcomes., (© 2016 The American Society of Transplantation and the American Society of Transplant Surgeons.)

Background: As healthcare reform moves toward value based care, hospitals must reduce costs. As a first step, here we developed a predictive model to identify high-cost patients on admission., Methods: We performed a retrospective observational study of 7,571 adults admitted to internal medicine services from July 1, 2013 to June 30, 2014. We compared the top 10% highest cost patients to other patients (controls) and identified clinical variables associated with high inpatient costs. Using logistic regression analyses, we developed a predictive model that could be used on admission to identify potential high utilization patients., Results: In the 757 high utilizer patients, the median total hospital cost was $53,430 ± 60,679 compared to $8,431 ± 7,245 in the control group (P < 0.0001). The median length of stay for high utilization patients was 19.5 ± 32.5 days compared to 3.8 ± 3.9 days in the control group (P < 0.001). Variables associated with high utilization included transfer from an outside hospital (odds ratio [OR] = 1.6), admission to the pulmonary or medical intensive care unit (OR = 2.4), admission to cardiology (OR = 1.8), coagulopathy (OR = 2.6) and fluid and electrolyte disorders (OR = 2.1). A multivariate logistic regression model was used to fit a predictive model for high utilizers. The receiver operating characteristics curve of this prediction model yielded an area under the curve of 0.80., Conclusions: High resource utilization patients appear to have a specific phenotype that can be predicted with commonly available clinical variables. Our predictive formula holds promise as a tool that may help ultimately reduce hospital costs., (Copyright © 2016 Southern Society for Clinical Investigation. Published by Elsevier Inc. All rights reserved.)

Purpose: This study retrospectively reviewed locally set pass rates/tolerances for COMPASS(®) pre-treatment quality assurance results for RapidArc prostate plans to determine if these are appropriate. This was performed via quantifying the agreement between treatment planning system calculations and measurements based on absolute dose comparisons (3% tolerance for all dose points) and global gamma index assessment (3%/3 mm criterion for 97% of points)., Method: Seventy-three prostate one-arc RapidArc plans, delivered by four dosimetrically matched linacs, were measured using the MatriXX Evolution two-dimensional array and analysed using COMPASS(®) (v.3, IBA Dosimetry). For the planning target volumes (PTV) considered, the D99%, D50%, D1% and DMean differences were analysed. The percentage volume with gamma greater than 1, average gamma and DMean difference were investigated for all structures. Nine plans were also assessed across the linac fleet to investigate potential linac dependence of results., Results and Conclusions: Regarding PTV DMean differences, all plans fell within the 3% tolerance and mostly within 2%, although there was a relatively small systematic difference. The absolute percentage differences of average and median doses suggested a weak linac dependence of the results which was found to be clinically insignificant. New stricter tolerances were established both for dose comparisons and gamma evaluation. Correlation between the gamma pass rates and the differences in the D99%, D50% and D1% was found to be moderate suggesting that gamma analysis in isolation has questionable clinical meaning and should only be used to indicate outliers for further analysis., (Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.)

Missed opportunities to vaccinate and refusal of vaccine by patients have hindered the achievement of national health care goals. The meaningful use of electronic medical records should improve vaccination rates, but few studies have examined the content of these records. In our vaccine intervention program using an electronic record with physician prompts, paper prompts, and nursing standing orders, we were unable to achieve national vaccine goals, due in large part to missing information and patient refusal., (Copyright © 2012 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.)

This paper uncovers novel and specific dynamical mechanisms that initiate large-amplitude collective motions in polyatomic molecules. These mechanisms are understood in terms of intramolecular energy transfer between modes and driving forces. Structural transition dynamics of a six-atom cluster between a symmetric and an elongated isomer is highlighted as an illustrative example of what is a general message. First, we introduce a general method of hyperspherical mode analysis to analyze the energy transfer among internal modes of polyatomic molecules. In this method, the (3n-6) internal modes of an n-atom molecule are classified generally into three coarse level gyration-radius modes, three fine level twisting modes, and (3n-12) fine level shearing modes. We show that a large amount of kinetic energy flows into the gyration-radius modes when the cluster undergoes structural transitions by changing its mass distribution. Based on this fact, we construct a reactive mode as a linear combination of the three gyration-radius modes. It is shown that before the reactive mode acquires a large amount of kinetic energy, activation or inactivation of the twisting modes, depending on the geometry of the isomer, plays crucial roles for the onset of a structural transition. Specifically, in a symmetric isomer with a spherical mass distribution, activation of specific twisting modes drives the structural transition into an elongated isomer by inducing a strong internal centrifugal force, which has the effect of elongating the mass distribution of the system. On the other hand, in an elongated isomer, inactivation of specific twisting modes initiates the structural transition into a symmetric isomer with lower potential energy by suppressing the elongation effect of the internal centrifugal force and making the effects of the potential force dominant. This driving mechanism for reactions as well as the present method of hyperspherical mode analysis should be widely applicable to molecular reactions in which a system changes its overall mass distribution in a significant way.

High-frequency (HF) radar technology produces detailed velocity maps near the surface of estuaries and bays. The use of velocity data in environmental prediction, nonetheless, remains unexplored. In this paper, we uncover a striking flow structure in coastal radar observations of Monterey Bay, along the California coastline. This complex structure governs the spread of organic contaminants, such as agricultural runoff which is a typical source of pollution in the bay. We show that a HF radar-based pollution release scheme using this flow structure reduces the impact of pollution on the coastal environment in the bay. We predict the motion of the Lagrangian flow structures from finite-time Lyapunov exponents of the coastal HF velocity data. From this prediction, we obtain optimal release times, at which pollution leaves the bay most efficiently.

This paper is concerned with the structural transition dynamics of the six-atom Morse cluster with zero total angular momentum, which serves as an illustrative example of the general reaction dynamics of isolated polyatomic molecules. It develops a methodology that highlights the interplay between the effects of the potential energy topography and those of the intrinsic geometry of the molecular internal space. The method focuses on the dynamics of three coarse variables, the molecular gyration radii. By using the framework of geometric mechanics and hyperspherical coordinates, the internal motions of a molecule are described in terms of these three gyration radii and hyperangular modes. The gyration radii serve as slow collective variables, while the remaining hyperangular modes serve as rapidly oscillating "bath" modes. Internal equations of motion reveal that the gyration radii are subject to two different kinds of forces: One is the ordinary force that originates from the potential energy function of the system, while the other is an internal centrifugal force. The latter originates from the dynamical coupling of the gyration radii with the hyperangular modes. The effects of these two forces often counteract each other: The potential force generally works to keep the internal mass distribution of the system compact and symmetric, while the internal centrifugal force works to inflate and elongate it. Averaged fields of these two forces are calculated numerically along a reaction path for the structural transition of the molecule in the three-dimensional space of gyration radii. By integrating the sum of these two force fields along the reaction path, an effective energy curve is deduced, which quantifies the gross work necessary for the system to change its mass distribution along the reaction path. This effective energy curve elucidates the energy-dependent switching of the structural preference between symmetric and asymmetric conformations. The present methodology should be of wide use for the systematic reduction of dimensionality as well as for the identification of kinematic barriers associated with the rearrangement of mass distribution in a variety of molecular reaction dynamics in vacuum.

We employ set oriented methods in combination with graph partitioning algorithms to identify key dynamical regions in the Sun-Jupiter-particle three-body system. Transport rates from a region near the 3:2 Hilda resonance into the realm of orbits crossing Mars' orbit are computed. In contrast to common numerical approaches, our technique does not depend on single long term simulations of the underlying model. Thus, our statistical results are particularly reliable since they are not affected by a dynamical behavior which is almost nonergodic (i.e., dominated by strongly almost invariant sets).

The introduction of zebra mussels ( Dreissena spp.) to North America has resulted in dramatic changes to the complexity of benthic habitats. Changes in habitat complexity may have profound effects on predator-prey interactions in aquatic communities. Increased habitat complexity may affect prey and predator dynamics by reducing encounter rates and foraging success. Zebra mussels form thick contiguous colonies on both hard and soft substrates. While the colonization of substrata by zebra mussels has generally resulted in an increase in both the abundance and diversity of benthic invertebrate communities, it is not well known how these changes affect the foraging efficiencies of predators that prey on benthic invertebrates. We examined the effect of zebra mussels on the foraging success of four benthic predators with diverse prey-detection modalities that commonly forage in soft substrates: slimy sculpin ( Cottus cognatus), brown bullhead ( Ameirus nebulosus), log perch ( Percina caprodes), and crayfish ( Orconectes propinquus). We conducted laboratory experiments to assess the impact of zebra mussels on the foraging success of predators using a variety of prey species. We also examined habitat use by each predator over different time periods. Zebra mussel colonization of soft sediments significantly reduced the foraging efficiencies of all predators. However, the effect was dependent upon prey type. All four predators spent more time in zebra mussel habitat than in either gravel or bare sand. The overall effect of zebra mussels on benthic-feeding fishes is likely to involve a trade-off between the advantages of increased density of some prey types balanced against the reduction in foraging success resulting from potential refugia offered in the complex habitat created by zebra mussels.

The purpose of this paper is to describe the general setting for the application of techniques from geometric mechanics and dynamical systems to the problem of asteroid pairs. The paper also gives some preliminary results on transport calculations and the associated problem of calculating binary asteroid escape rates. The dynamics of an asteroid pair, consisting of two irregularly shaped asteroids interacting through their gravitational potential is an example of a full-body problem or FBP in which two or more extended bodies interact. One of the interesting features of the binary asteroid problem is that there is coupling between their translational and rotational degrees of freedom. General FBPs have a wide range of other interesting aspects as well, including the 6-DOF guidance, control, and dynamics of vehicles, the dynamics of interacting or ionizing molecules, the evolution of small body, planetary, or stellar systems, and almost any other problem in which distributed bodies interact with each other or with an external field. This paper focuses on the specific case of asteroid pairs using techniques that are generally applicable to many other FBPs. This particular full two-body problem (F2BP) concerns the dynamical evolution of two rigid bodies mutually interacting via a gravitational field. Motivation comes from planetary science, where these interactions play a key role in the evolution of asteroid rotation states and binary asteroid systems. The techniques that are applied to this problem fall into two main categories. The first is the use of geometric mechanics to obtain a description of the reduced phase space, which opens the door to a number of powerful techniques, such as the energy-momentum method for determining the stability of equilibria and the use of variational integrators for greater accuracy in simulation. Second, techniques from computational dynamic systems are used to determine phase space structures that are important for transport phenomena and dynamic evolution.

The 1:1 resonance for perturbed Hamiltonian systems with small dissipative and energy injection terms has been studied. These perturbations of the 1:1 resonance exhibit dissipation induced instabilities. This mechanism allows one to show that an optical cavity with small pumping is unstable when one takes into account the dissipative effects. The Maxwell-Bloch equations are the asymptotic normal form that describe this instability when energy is injected through forcing at zero frequency. A simple mechanical system close to the 1:1 resonance has been displayed, which is a mechanical analog of the laser.

In this paper we apply dynamical systems techniques to the problem of heteroclinic connections and resonance transitions in the planar circular restricted three-body problem. These related phenomena have been of concern for some time in topics such as the capture of comets and asteroids and with the design of trajectories for space missions such as the Genesis Discovery Mission. The main new technical result in this paper is the numerical demonstration of the existence of a heteroclinic connection between pairs of periodic orbits: one around the libration point L(1) and the other around L(2), with the two periodic orbits having the same energy. This result is applied to the resonance transition problem and to the explicit numerical construction of interesting orbits with prescribed itineraries. The point of view developed in this paper is that the invariant manifold structures associated to L(1) and L(2) as well as the aforementioned heteroclinic connection are fundamental tools that can aid in understanding dynamical channels throughout the solar system as well as transport between the "interior" and "exterior" Hill's regions and other resonant phenomena. (c) 2000 American Institute of Physics.

Objective: To assess the training that accident and emergency (A&E) senior house officers (SHOs) receive in dealing with eye emergencies, their own perceived level of confidence and competence in managing such cases, and the availability of appropriate equipment in their departments., Methods: Prospective telephone survey using a standardised structured questionnaire. One SHO from each United Kingdom A&E department listed in the BAEM directory of 1993 was chosen at random and interviewed., Results: 226 A&E departments were contacted and 192 SHOs were successfully interviewed (response rate 84.9%); 26.0% received no training in the management of eye emergencies, 68.8% had only a little or no confidence in dealing with these cases, and 42.2% worked in A&E departments which had no slit lamp., Conclusions: There is a lack of adequate basic ophthalmic training for A&E SHOs, leading to a lack of confidence on their part in the management of eye emergencies. In just over 40% of A&E departments in the United Kingdom, the management of these cases may be less than optimal because of the absence of a slit lamp.

Two polymorphic, duplicated loci (fumarase-1,2 and phosphoglucomutase-3,4), previously undescribed in salmonids, were examined in lake trout to determine their electrophoretic expression, mode of inheritance, and linkage associations. Both loci appear to be located on chromosomes which show residual tetrasomy. Neither locus pair shows joint segregation with other loci examined or with each other.

The recently evolved autotetraploid frog, Hyla versicolor , was examined electrophoretically for evidence of genomic restructuring leading to diploidization. Loci were tested against the progeny ratios expected if inheritance was disomic vs. tetrasomic. Two loci (Mpi and Sod-2) appeared to be inherited tetrasomically, one (Mdh-2) appeared to be inherited disomically, and one (Tpi) appeared to be inherited disomically in one family and tetrasomically in another family, when tested conventionally against 1:2:1 and 1:4:1 segregation ratios. The minimum number of progeny required for this type of analysis for codominant alleles is shown to be 92. Progeny resulting from double reduction were observed, and the occurrence of a null allele class at Mpi was noted. A reexamination of expected progeny ratios in tetraploid organisms reveals that tetrasomic inheritance patterns cannot be predicted without adequate knowledge of the amount of crossing-over, the proportion of tetravalents vs. random bivalents that are formed, and the ratio and types of centromere segregation (alternate and adjacent) that occur from tetravalents in the species being studied. However, disomic inheritance can be unambiguously confirmed only by the production of all heteroallelic gametes from homobivalent, symmetrically heterozygous individuals. In addition, a method is described for estimating genecentromere distances using the ratio of progeny genotypes in certain crosses in tetraploid species.

We measured oxygen consumption of the diploid frog Hyla chrysoscelis and its recently evolved tetraploid cryptic species Hyla versicolor at rest and during forced locomotory exercise. We also measured whole-body lactic acid concentrations of individuals of the two species at rest and following 4 min of exercise. Contrary to predictions based on tissue-culture experiments, rates of organismal metabolism are not different in this diploid/tetraploid species pair: the diploid and tetraploid species did not differ in rates of oxygen consumption at rest or during exercise. Furthermore, whole-body lactate concentrations of frogs at rest and following forced locomotion were the same in the diploid and tetraploid species. For these species, polyploidy does not appear to be associated with lower maintenance costs at the level of the organism. However, polyploidy also does not appear to have metabolic consequences that would limit the behavioral or ecological repertoire of an anuran.