Unearthing who and Y at Harewood Cemetery and inference of George Washington's Y-chromosomal haplotype.

An excavation conducted at Harewood Cemetery to identify the unmarked grave of Samuel Washington resulted in the discovery of burials presumably belonging to George Washington's paternal grandnephews and their mother, Lucy Payne. To confirm their identities this study examined Y-chromosomal, mitochondrial, and autosomal DNA from the burials and a living Washington descendant. The burial's Y-STR profile was compared to FamilyTreeDNA's database, which resulted in a one-step difference from the living descendant and an exact match to another Washington. A more complete Y-STR and Y-SNP profile from the descendant was inferred to be the Washington Y profile. Kinship comparisons performed in relation to the descendant, who is a 4th and 5th degree relative of the putative individuals, resulted in >37,000 overlapping autosomal SNPs and strong statistical support with likelihood ratios exceeding one billion. This study highlights the benefits of a multi-marker approach for kinship prediction and DNA-assisted identification of historical remains.

Arginine Acts as both Co-Solvent and Catalyst in Regioselective Eutectic-Mediated Dimerization of Levulinic Acid.

A simple, solvent-free arginine-catalyzed aldol dimerization of levulinic acid was achieved via the simultaneous formation of a eutectic mixture. Dimers of levulinic acid are valued as biomass-derived fine chemical precursors, with potential to upgrade to bio-jet fuels or N-containing functional chemicals. Typically, these dimers are produced as isomeric mixtures using high temperatures and a variety of solid inorganic catalysts or mineral acids. In this study, an organocatalytic and regioselective dimerization was achieved at 22 % conversion on either a bench or kilogram scale using mild temperatures and only L-arginine as both a co-solvent and catalyst. The intricate H-bonding network comprising the eutectic solvent was harnessed to produce only one product, minimizing side reactivity and preserving the reactants for recycling.

A spatial framework for improved sanitation to support coral reef conservation.

Coral reefs are one of the most valuable yet threatened ecosystems in the world. Improving human wastewater treatment could reduce land-based impacts on coral reefs. However, information on the quantity and spatial distribution of human wastewater pollution is lacking. Here, we develop a spatial model linking residential human wastewater pollution (nitrogen and phosphorus/year) and conservation sectors [coral reefs] to better understand the relative differences in the distribution and efficacy of different sanitation services and their potential implications for conservation monitoring and management. We apply our model to Fiji, where ongoing initiatives and investments in wastewater treatment for human health could be leveraged to cost-effectively improve coral reef condition. We estimate that wastewater treatment plants account for nearly 80% of human wastewater nutrients released into surface waters. Wasterwater nutrient pollution is widespread, affecting 95% of reefs, but is concentrated across a few watersheds. Our spatially explicit approach can be used to better understand potential benefits and trade-offs between sanitation service improvements and coral reef health, helping to bridge the sanitation and conservation sectors as well as inform and prioritize on the ground action.

A review of latrine front-end characteristics associated with microbial infection risk; reveals a lack of pathogen density data.

Unsafe sanitation accounts for an estimated 898,000 global deaths annually. The faecal pathogen transmission pathway is complex with several possible routes. Latrine front-end characteristics and usage behaviours are one key transmission pathway for microbial pathogens, however, there has not yet been a synthesis of the available research. This review aims to compare the microbial infection risks with latrine front-end components including any quantified microbial densities within the household latrines. This review was conducted with no restriction on the geographical location of the research. Of 118 studies reviewed, only ten (8%) have quantified the microbial density inside the household latrines compared to 109 (92%) measuring the infection risks. The reported risks were most frequent for specific bacterial (n = 34), and helminths infections (n = 32) compared to diarrhoea (n = 23), combined (n = 15), protozoan (n = 4), and viral (n = 4) infections. The infections risk decreased for using latrines lying at a higher position on the sanitation ladder (for example flush latrines) compared to those lying lower (for example pit latrines). The trend was similar for using floor materials that were easier to clean and less favourable for pathogen survival inside the latrines (for example, concrete as opposed to earth). Faecal coliforms were reported highest on the surface of the squat pan (743 CFU/cm2) of pour-flush latrines and helminths on earth floors of pit latrines (1.5 eggs and larvae per gram of soil). Irrespective of latrine type and its position on the sanitation ladder, a dirty latrine, evidenced by a visible lack of cleanliness, significantly increased the risk for all infections. This study recommends that effective microbial infection risk reduction in latrines can be gained efficiently by ensuring washable surfaces and consistent cleaning practices. Future studies should include more rigorous measurements of microbial densities in various latrine types incorporating the different front-end components and usage behaviours.

Evaluating the Usefulness of Human DNA Quantification to Predict DNA Profiling Success of Historical Bone Samples.

This study assessed the usefulness of DNA quantification to predict the success of historical samples when analyzing SNPs, mtDNA, and STR targets. Thirty burials from six historical contexts were utilized, ranging in age from 80 to 800 years postmortem. Samples underwent library preparation and hybridization capture with two bait panels (FORCE and mitogenome), and STR typing (autosomal STR and Y-STR). All 30 samples generated small (~80 bp) autosomal DNA target qPCR results, despite mean mappable fragments ranging from 55-125 bp. The qPCR results were positively correlated with DNA profiling success. Samples with human DNA inputs as low as 100 pg resulted in ≥80% FORCE SNPs at 10X coverage. All 30 samples resulted in mitogenome coverage ≥100X despite low human DNA input (as low as 1 pg). With PowerPlex Fusion, ≥30 pg human DNA input resulted in >40% of auSTR loci. At least 59% of Y-STR loci were recovered with Y-target qPCR-based inputs of ≥24 pg. The results also indicate that human DNA quantity is a better predictor of success than the ratio of human to exogenous DNA. Accurate quantification with qPCR is feasible for historical bone samples, allowing for the screening of extracts to predict the success of DNA profiling.

Understanding Ecotoxicological Responses of Fish Embryos and Gill Cells to Cationic Polymers.

Cationic polymers are considered by the scientific and regulatory communities as a group of greater interest amongst the polymers in commerce. As a category, relatively little hazard information is available in the public literature. Very few examples exist of published, high-quality polymer characterization and quantification of exposure. In the present study we describe a series of fish embryo toxicity (FET) and fish gill cytotoxicity assays used to establish a baseline understanding of several representative polyquaternium categories (PQ-6, PQ-10, PQ-16) in animal alternative models, accompanied by high-quality analytical characterization. Materials were chosen to encompass a range of molecular weights and charge densities to determine the influence of test material characteristics on toxicity. Both chorionated and dechorionated FET assays were generally similar to published acute fish toxicity data. Toxicity was correlated with cationic polymer charge density, and not with molecular weight, and was a combination of physical effects and likely toxicity at the site of action. Toxicity could be ameliorated by humic acid in a dose-dependent manner. Fish gill cytotoxicity results were orders of magnitude less sensitive than FET test responses. Environ Toxicol Chem 2022;41:2259-2272. © 2022 SETAC.

A review of rural and peri-urban sanitation infrastructure in South-East Asia and the Western Pacific: Highlighting regional inequalities and limited data.

Rural and peri-urban communities in developing countries rely on sanitation systems which are often unsafely managed. One of the major barriers to assess safely managed sanitation is a lack of data about the existing sanitation infrastructure and levels of containment safety. The aim was to review rural and peri-urban on-site sanitation studies in order to understand different infrastructure types, associated management practices and any impacts on human health. The scope was limited to South-East Asia and Western Pacific regions in order to better identify regional inequalities. Among the 155 reviewed articles, 73 studies (47%) linked sanitation infrastructure to poor human health. Nearly all articles reported latrine ownership (n = 149, 96%) while sanitation infrastructure types were covered less frequently (n = 104, 67%). In particular, there was a lack of published literature describing back-end characteristics (dimension and materials) (n = 12, 8%) and/or management practices (n = 4, 3%). This stems from a limited application of research methodologies that characterise sanitation infrastructure and faecal sludge management (containment, emptying and on-site treatment). Inequality between regions was prevalent with three quarters of the studies on latrine back-end infrastructure from Bangladesh and India in South-East Asia. A strategic research approach is needed to address the current knowledge gaps regarding sanitation infrastructure and safe faecal sludge management.

Ancient DNA Methods Improve Forensic DNA Profiling of Korean War and World War II Unknowns.

The integration of massively parallel sequencing (MPS) technology into forensic casework has been of particular benefit to the identification of unknown military service members. However, highly degraded or chemically treated skeletal remains often fail to provide usable DNA profiles, even with sensitive mitochondrial (mt) DNA capture and MPS methods. In parallel, the ancient DNA field has developed workflows specifically for degraded DNA, resulting in the successful recovery of nuclear DNA and mtDNA from skeletal remains as well as sediment over 100,000 years old. In this study we use a set of disinterred skeletal remains from the Korean War and World War II to test if ancient DNA extraction and library preparation methods improve forensic DNA profiling. We identified an ancient DNA extraction protocol that resulted in the recovery of significantly more human mtDNA fragments than protocols previously used in casework. In addition, utilizing single-stranded rather than double-stranded library preparation resulted in increased attainment of reportable mtDNA profiles. This study emphasizes that the combination of ancient DNA extraction and library preparation methods evaluated here increases the success rate of DNA profiling, and likelihood of identifying historical remains.

Adoption of virtual reality technology in higher education: An evaluation of five teaching semesters in a purpose-designed laboratory.

Virtual and augmented (VAR) technology is in the early stages of being adopted as a teaching platform in higher education. The technology can facilitate immersive learning in environments that are not usually physically accessible to students via 3D models and interactive 360° videos. To date, adoption rates of VAR technology for teaching have not been well described across a higher education institution. Further, there is an absence of information on the optimal VAR laboratory designs and cost per student. In this study, a purpose designed virtual reality laboratory was formed in 2017 at The University of Sydney, housing 26 Oculus Rift headset units. An evaluation was conducted on the design, costs, rates of teaching adoption and student experiences over five teaching periods (2.5 years). Over this period, 4833 students were taught in the laboratory across 7952 student visits. The laboratory was used most by the Faculty of Engineering (53%), followed by the Faculty of Arts & Social Science (23.8%) and Faculty of Science (23.2%). For engineering, the units of study using the laboratory represented only 1.4% of annual faculty subjects offered. This confirms that adoption was in the initial stage of innovation diffusion. The laboratory saw a 250% increase in student numbers over the period of evaluation and 71.5% of students surveyed (n = 295) reported enhanced learning outcomes. The cost per visit was only AU$ 19.50. These findings give confidence to higher education institutions that the right VAR technology infrastructure is a sound educational investment for the future. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10639-021-10653-6.

Infrastructure alone cannot ensure resilience to weather events in drinking water supplies.

Climate resilient water supplies are those that provide access to drinking water that is sustained through seasons and through extreme events, and where good water quality is also sustained. While surface and groundwater quality are widely understood to vary with rainfall, there is a gap in the evidence on the impact of weather and extremes in rainfall and temperature on drinking water quality, and the role of changes in water system management. A three-country (Bangladesh, Nepal and Tanzania) observational field study tracked 2353 households clustered around 685 water sources across seven different geographies over 14 months. Water quality (E. coli) data was modelled using GEE to account for clustering effects and repeated measures at households. All types of infrastructure were vulnerable to changes in weather, with differences varying between geographies; protected boreholes provided the greatest protection at the point of collection (PoC). Water quality at the point of use (PoU) was vulnerable to changes in weather, through changes in PoC water quality as well as changes in management behaviours, such as safe storage, treatment and cleaning. This is the first study to demonstrate the impact of rainfall and temperature extremes on water quality at the PoC, and the role that weather has on PoU water quality via management behaviours. Climate resilience for water supplies needs to consider the infrastructure as well as the management decisions that are taking place at a community and household level.

The FORCE Panel: An All-in-One SNP Marker Set for Confirming Investigative Genetic Genealogy Leads and for General Forensic Applications.

The FORensic Capture Enrichment (FORCE) panel is an all-in-one SNP panel for forensic applications. This panel of 5422 markers encompasses common, forensically relevant SNPs (identity, ancestry, phenotype, X- and Y-chromosomal SNPs), a novel set of 3931 autosomal SNPs for extended kinship analysis, and no clinically relevant/disease markers. The FORCE panel was developed as a custom hybridization capture assay utilizing ~20,000 baits to target the selected SNPs. Five non-probative, previously identified World War II (WWII) cases were used to assess the kinship panel. Each case included one bone sample and associated family reference DNA samples. Additionally, seven reference quality samples, two 200-year-old bone samples, and four control DNAs were processed for kit performance and concordance assessments. SNP recovery after capture resulted in a mean of ~99% SNPs exceeding 10X coverage for reference and control samples, and 44.4% SNPs for bone samples. The WWII case results showed that the FORCE panel could predict first to fifth degree relationships with strong statistical support (likelihood ratios over 10,000 and posterior probabilities over 99.99%). To conclude, SNPs will be important for further advances in forensic DNA analysis. The FORCE panel shows promising results and demonstrates the utility of a 5000 SNP panel for forensic applications.

Salt- and pH-Dependent Viscosity of SDS/LAPB Solutions: Experiments and a Semiempirical Thermodynamic Model.

We present novel data on the composition-, pH-, and salt-dependent zero shear viscosity of the commercially important mixture of anionic sodium dodecyl sulfate (SDS) and zwitterionic lauramidopropyl betaine (LAPB). We show via proton NMR experiments that the notionally zwitterionic LAPB exhibits a large pKa shift in the presence of SDS and can become partially cationic at formulation-relevant pH ranges of 4.5-6.0-that is, the binary system is effectively a ternary system. This has a pronounced effect on the viscosity of the system at low pH, especially if the fraction of LAPB is high. We use theoretical arguments to motivate a semiempirical but practical approach to model the viscosity of the mixtures using thermodynamic parameters such as the excess chemical potentials or activity coefficients of the surfactants. We demonstrate this using an augmented regular solution theory-based mixed micelle thermodynamic model and develop robust regression models using Bayesian approaches. We also show how the pKa shift from NMR experiments can be used to parameterize the thermodynamic model. This framework should be extensible to other arbitrary surfactant mixtures in the future and hence will be of broad interest for the development of surfactant formulations for household, personal care, and other applications.

Guideline No. 414: management of pregnancy of unknown location and tubal and nontubal ectopic pregnancies

To provide an evidence-based algorithm to guide the diagnosis and management of pregnancy of unknown location and tubal and nontubal ectopic pregnancy. All patients of reproductive age. The implementation of this guideline aims to benefit patients with positive ß-human chorionic gonadotropin results and provide physicians with a standard algorithm for expectant, medical, and surgical treatment of pregnancy of unknown location and tubal pregnancy and nontubal ectopic pregnancies. The following search terms were entered into PubMed/Medline and Cochrane in 2018: cesarean section, chorionic gonadotropin, beta subunit, human/blood, fallopian tubes/surgery, female, fertility, humans, infertility, laparoscopy, methotrexate, methotrexate/administration & dosage,methotrexate/therapeutic use, pregnancy (abdominal, angular, cervix, cornual, ectopic, ectopic/diagnosis, ectopic/diagnostic imaging, ectopic/drug therapy, ectopic/epidemiology, ectopic/mortality, ectopic/surgery, heterotopic, interstitial, isthmo-cervical, ovarian, tubal, unknown location), recurrence, risk factors, salpingectomy, salpingostomy, tubal pregnancy, ultrasonography, doppler ultrasonography, and prenatal. Articles included were randomized controlled trials, meta-analyses, systematic reviews, observational studies, and case reports. Additional publications were identified from the bibliographies of these articles. Only English-language articles were reviewed. The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and weak recommendations). Obstetrician-gynaecologists, family physicians, emergency physicians, midwives, registered nurses, nurse practitioners, medical students, and residents and fellows.

Directive clinique no 414 : Prise en charge des grossesses de localisation indéterminée et des grossesses ectopiques tubaires et non tubaires.

OBJECTIF: Fournir un algorithme fondé sur des données probantes pour orienter le diagnostic et la prise en charge de la grossesse de localisation indéterminée et de la grossesse ectopique tubaire ou non tubaire. POPULATION CIBLE: Toutes les patientes en âge de procréer. BéNéFICES, RISQUES ET COûTS: La mise en œuvre de la présente directive a pour objectif de bénéficier aux patientes ayant obtenu un résultat positif pour la sous-unité bêta de la gonadotrophine chorionique et de fournir aux médecins un algorithme normalisé pour l'expectative et le traitement pharmacologique ou chirurgical en cas de grossesse de localisation indéterminée et de grossesse ectopique tubaire ou non tubaire. DONNéES PROBANTES: Les termes de recherche suivants ont été entrés dans les bases de données PubMed-Medline et Cochrane en 2018 : cesarean section, chorionic gonadotropin, beta subunit, human/blood, fallopian tubes/surgery, female, fertility, humans, infertility, laparoscopy, methotrexate, methotrexate/administration & dosage, methotrexate/therapeutic use, pregnancy (abdominal, angular, cervix, cornual, ectopic, ectopic/diagnosis, ectopic/diagnostic imaging, ectopic/drug therapy, ectopic/epidemiology, ectopic/mortality, ectopic/surgery, heterotopic, interstitial, isthmo-cervical, ovarian, tubal, unknown location), recurrence, risk factors, salpingectomy, salpingostomy, tubal pregnancy, ultrasonography, doppler ultrasonography et prenatal. Les articles retenus sont des essais cliniques randomisés, des méta-analyses, des revues systématiques, des études observationnelles et des études de cas. Des publications supplémentaires ont été sélectionnées à partir des notices bibliographiques de ces articles. Seuls les articles en anglais ont été examinés. MéTHODES DE VALIDATION: Les auteurs ont évalué la qualité des données probantes et la solidité des recommandations en utilisant la méthodologie GRADE (Grading of Recommendations Assessment, Development and Evaluation). Voir l'annexe A en ligne (tableau A1 pour les définitions et tableau A2 pour l'interprétation des recommandations fortes et faibles). PUBLIC VISé: Obstétriciens-gynécologues, médecins de famille, urgentologues, sages-femmes, infirmières autorisées, infirmières praticiennes, étudiants en médecine, résidents et moniteurs cliniques. DÉCLARATIONS SOMMAIRES (CLASSEMENT GRADE ENTRE PARENTHèSES): RECOMMANDATIONS (CLASSEMENT GRADE ENTRE PARENTHèSES).

Guideline No. 414: Management of Pregnancy of Unknown Location and Tubal and Nontubal Ectopic Pregnancies.

OBJECTIVE: To provide an evidence-based algorithm to guide the diagnosis and management of pregnancy of unknown location and tubal and nontubal ectopic pregnancy. TARGET POPULATION: All patients of reproductive age. BENEFITS, HARMS, AND COSTS: The implementation of this guideline aims to benefit patients with positive ß-human chorionic gonadotropin results and provide physicians with a standard algorithm for expectant, medical, and surgical treatment of pregnancy of unknown location and tubal pregnancy and nontubal ectopic pregnancies. EVIDENCE: The following search terms were entered into PubMed/Medline and Cochrane in 2018: cesarean section, chorionic gonadotropin, beta subunit, human/blood, fallopian tubes/surgery, female, fertility, humans, infertility, laparoscopy, methotrexate, methotrexate/administration & dosage, methotrexate/therapeutic use, pregnancy (abdominal, angular, cervix, cornual, ectopic, ectopic/diagnosis, ectopic/diagnostic imaging, ectopic/drug therapy, ectopic/epidemiology, ectopic/mortality, ectopic/surgery, heterotopic, interstitial, isthmo-cervical, ovarian, tubal, unknown location), recurrence, risk factors, salpingectomy, salpingostomy, tubal pregnancy, ultrasonography, doppler ultrasonography, and prenatal. Articles included were randomized controlled trials, meta-analyses, systematic reviews, observational studies, and case reports. Additional publications were identified from the bibliographies of these articles. Only English-language articles were reviewed. VALIDATION METHODS: The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and weak recommendations). INTENDED AUDIENCE: Obstetrician-gynaecologists, family physicians, emergency physicians, midwives, registered nurses, nurse practitioners, medical students, and residents and fellows. SUMMARY STATEMENTS (GRADE RATINGS IN PARENTHESES): RECOMMENDATIONS (GRADE RATINGS IN PARENTHESES).

Modelling the influence of short-term climate variability on drinking water quality in tropical developing countries: A case study in Tanzania.

Climate change is expected to increase the prevalence of water-borne diseases especially in developing countries. Climate-resilient drinking water supplies are critical to protect communities from faecal contamination and thus against increasing disease risks. However, no quantitative assessment exists for the impacts of short-term climate variability on faecal contamination at different drinking water sources in developing countries, while existing understanding remains largely conceptual. This critical gap limits the ability to predict drinking water quality under climate change or to recommend climate-resilient water sources for vulnerable communities. This study aims to provide such quantitative understanding by investigating the relationships between faecal contamination and short-term climate variability across different types of water sources. We collected a novel dataset with over 20 months' monitoring of weather, Escherichia coli (E. coli) and total coliforms, at 233 different water sources in three climatically different regions in Tanzania. We then took a rigorous statistical analysis with Bayesian hierarchical models, to relate both contamination occurrence and amount to climate variability. The model results explained the temporal variability in drinking water faecal contamination using climate predictors, and also revealed the climate sensitivity of faecal contamination for individual water sources. We found that: a) short-term climate variability and baseline contamination levels can explain about half the observed variability in faecal contamination (R2 ≥ 0.44); b) increased contamination was most consistently related to recent heavy rainfall and high temperature across different water sources; c) unimproved water sources such as the unprotected dug wells have substantially higher climate sensitivity. Based on these results, we can expect substantial increases in drinking water contamination risks across tropical Sub-Saharan Africa and South-East Asian developing countries under a warmer climate, which highlight the urgent need of protecting vulnerable communities from the severe climate impacts.

Labour Management in Trial of Labour After Cesarean Delivery (TOLAC): A Gap Analysis and Quality Improvement Initiative.

OBJECTIVE: This quality improvement (QI) initiative was designed to identify gaps between evidence-based or hospital recommendations for trial of labour after cesarean delivery (TOLAC) labour management and clinical practice. METHODS: Viable, singleton pregnancies from January 1, 2016, to December 31, 2018, undergoing TOLAC were extracted from the electronic medical record. Sixty randomly selected charts were reviewed for (1) consent, (2) induction methods, (3) oxytocin use, (4) continuous fetal monitoring, (5) admission indication, (6) examination regularity, (7) duration of dystocia before decision to perform cesarean delivery (CD), and (8) maternal complications. RESULTS: The institutional vaginal birth after cesarean rate was 71%. Documented consent to TOLAC on admission was present in 50% of cases. Oxytocin augmentation was used in 38% of cases, and the median maximum dose was 4 mU/min (interquartile range [IQR] 3-7.5 mU/min). Delays in initiating oxytocin were identified in 47% of those patients. Decisions to deliver by cesarean were made after a median time of 5 hours and 40 minutes (IQR 3 hours and 30 minutes to 6 hours and 35 minutes) of failure to progress despite adequate contractions. After this decision, median time to delivery was 1 hour and 11 minutes (IQR 57 minutes to 2 hours and 16 minutes). Complications included postpartum hemorrhage (5%) and chorioamnionitis (6.7%). Surgical injury occurred in 10% of intrapartum CD. Peripartum complications were associated with delay in oxytocin implementation (χ2 (1) = 9.80; P < 0.001) in secondary analysis. CONCLUSION: Areas for QI were identified in (1) consent, (2) duration of dystocia before decision to proceed with CD and delay to CD, and (3) peripartum complications. We recognize the potential use of this as a tool to identify areas for QI and prospective study.

Understanding the Impacts of Short-Term Climate Variability on Drinking Water Source Quality: Observations From Three Distinct Climatic Regions in Tanzania.

Climate change is expected to increase waterborne diseases especially in developing countries. However, we lack understanding of how different types of water sources (both improved and unimproved) are affected by climate change, and thus, where to prioritize future investments and improvements to maximize health outcomes. This is due to limited knowledge of the relationships between source water quality and the observed variability in climate conditions. To address this gap, a 20-month observational study was conducted in Tanzania, aiming to understand how water quality changes at various types of sources due to short-term climate variability. Nine rounds of microbiological water quality sampling were conducted for Escherichia coli and total coliforms, at three study sites within different climatic regions. Each round included approximately 233 samples from water sources and 632 samples from households. To identify relationships between water quality and short-term climate variability, Bayesian hierarchical modeling was adopted, allowing these relationships to vary with source types and sampling regions to account for potentially different physical processes. Across water sources, increases in E. coli/total coliform levels were most closely related to increases in recent heavy rainfall. Our key recommendations to future longitudinal studies are (a) demonstrated value of high sampling frequency and temporal coverage (a minimum of 3 years) especially during wet seasons; (b) utility of the Bayesian hierarchical models to pool data from multiple sites while allowing for variations across space and water sources; and (c) importance of a multidisciplinary team approach with consistent commitment and sharing of knowledge.

Enthalpy and Entropy of Scission in Wormlike Micelles.

The free scission energy is the thermodynamic parameter that governs the contour length of wormlike micelles (WLMs). It is the contour length and the propensity to coil and entangle that determine the viscoelastic properties of this commercially important substance class. The free scission energy Δ Fsc and the associated change in enthalpy Δ Hsc and entropy Δ Ssc on scission have been determined for a mixed anionic/zwitterionic surfactant system (sodium laureth sulfate and cocamidopropyl betaine) at various salt concentrations (3-5 wt % NaCl). Both enthalpy Δ Hsc and entropy Δ Ssc changes decrease linearly with increasing NaCl concentration. At NaCl concentrations above 4 wt %, Δ Ssc even adopts negative values. The term TΔ Ssc decreases more rapidly than Δ Hsc around room temperature and causes the observed elongation of WLMs upon addition of NaCl. It is suggested that Δ Ssc is initially positive due to fewer bound counterions per surfactant molecule at end caps compared to the intact, cylindrical parts before scission, leading to a net release of ions upon scission. Negative values of Δ Ssc are attributed to hydrophobic hydration occurring at the end caps at high salt concentrations. 23Na NMR measurements indicate the presence of immobilized ions, supporting a previously proposed ion-cloud model based on neutron scattering results.