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Lakes, reservoirs, and other ponded waters are ubiquitous features of the aquatic landscape, yet their cumulative role in nitrogen removal in large river basins is often unclear. Here we use predictive modeling, together with comprehensive river water quality, land use, and hydrography datasets, to examine and explain the influences of more than 18,000 ponded waters on nitrogen removal through river networks of the Northeastern United States. Thresholds in pond density where ponded waters become important features to regional nitrogen removal are identified and shown to vary according to a ponded waters’ relative size, network position, and degree of connectivity to the river network, which suggests worldwide importance of these new metrics. Consideration of the interacting physical and biological factors, along with thresholds in connectivity, reveal where, why, and how much ponded waters function differently than streams in removing nitrogen, what regional water quality outcomes may result, and in what capacity management strategies could most effectively achieve desired nitrogen loading reduction. Lakes, reservoirs, and other ponded waters are common in large river basins yet their influence on nitrogen budgets is often indistinct. Here, the authors show how a ponded waters’ relative size, shape, and degree of connectivity to the river network control nitrogen removal.

The most widely accepted model for the colonization of Remote Oceania by Austronesian-speaking bearers of the Lapita complex ~ 3 ka (3000 years ago) links it to a broader Neolithic expansion from China, via Taiwan, ~ 4.5–6 ka. However, analyses of mitochondrial DNA haplogroup B4a1a1a, prevalent among Remote Oceanians today, have both supported and challenged this scenario. Here, we analyze 1364 B4a1a1 mitogenomes (234 novel) from 68 islands and compare age estimates with radiocarbon dates for colonization. We estimate the settlement of Remote Oceania ~ 3.2 [2.7; 3.75] ka, matching radiocarbon ages, and then extrapolate the age in Near Oceania. B4a1a1a arose around the northern coasts of New Guinea at least 6 ka, following Early Holocene dispersals from Asia. Technological advances (e.g., in sailing), fueled by interaction networks alongside the arrival of Late Holocene migrants from Taiwan or ISEA and putative environmental changes, likely triggered the expansion of Lapita colonists carrying B4a1a1a from New Guinea into Remote Oceania.

There are two very different interpretations of the prehistory of Island Southeast Asia (ISEA), with genetic evidence invoked in support of both. The “out-of-Taiwan” model proposes a major Late Holocene expansion of Neolithic Austronesian speakers from Taiwan. An alternative, proposing that Late Glacial/postglacial sea-level rises triggered largely autochthonous dispersals, accounts for some otherwise enigmatic genetic patterns, but fails to explain the Austronesian language dispersal. Combining mitochondrial DNA (mtDNA), Y-chromosome and genome-wide data, we performed the most comprehensive analysis of the region to date, obtaining highly consistent results across all three systems and allowing us to reconcile the models. We infer a primarily common ancestry for Taiwan/ISEA populations established before the Neolithic, but also detected clear signals of two minor Late Holocene migrations, probably representing Neolithic input from both Mainland Southeast Asia and South China, via Taiwan. This latter may therefore have mediated the Austronesian language dispersal, implying small-scale migration and language shift rather than large-scale expansion.

Objectives: The objectives are to compare SF-6D, standard gamble (SG), and Health Utilities Index (HUI) utility scores, compare change scores, and compare responsiveness. Methods: A cohort of osteoarthritis patients referred for total hip arthroplasty (THA) were evaluated at the time of referral and followed until 3 months after THA. Patients were assessed using the SF-36, HUI2, HUI3, and the SG. Agreement is assessed using the intra-class correlation (ICC). Responsiveness is assessed using effect size, standardized response mean, and paired t-test. Results: Data was available for 86 patients at baseline and for 63 at both pre- and post-surgery. At baseline mean SF-6D (0.61), SG (0.62), and HUI2 (0.62) scores were similar; the mean HUI3 score (0.52) was lower. Standard deviations were 0.10, 0.32, 0.19, and 0.22. At baseline, agreement between SF-6D and SG scores was 0.13, agreement between SF-6D and HUI2 was 0.47, and agreement between SF-6D and HUI3 was 0.28. Agreement at pre- and post-surgery was similar. The change in scores between post- and pre-surgery was 0.10 for SF-6D, 0.16 for SG, 0.22 for HUI2, and 0.23 for HUI3. Effect sizes were 1.10 for HUI2, 1.08 for HUI3, 1.06 for SF-6D, and 0.48 for the SG. Conclusions: Agreement between SG scores and SF-6D and HUI scores was low. The estimate of change in utility associated with THA was lowest for SF-6D. Additional longitudinal studies to compare utility measures appear to be warranted.

There has been a long-standing debate concerning the extent to which the spread of Neolithic ceramics and Malay-Polynesian languages in Island Southeast Asia (ISEA) were coupled to an agriculturally driven demic dispersal out of Taiwan 4000 years ago (4 ka). We previously addressed this question using founder analysis of mitochondrial DNA (mtDNA) control-region sequences to identify major lineage clusters most likely to have dispersed from Taiwan into ISEA, proposing that the dispersal had a relatively minor impact on the extant genetic structure of ISEA, and that the role of agriculture in the expansion of the Austronesian languages was therefore likely to have been correspondingly minor. Here we test these conclusions by sequencing whole mtDNAs from across Taiwan and ISEA, using their higher chronological precision to resolve the overall proportion that participated in the “out-of-Taiwan” mid-Holocene dispersal as opposed to earlier, postglacial expansions in the Early Holocene. We show that, in total, about 20 % of mtDNA lineages in the modern ISEA pool result from the “out-of-Taiwan” dispersal, with most of the remainder signifying earlier processes, mainly due to sea-level rises after the Last Glacial Maximum. Notably, we show that every one of these founder clusters previously entered Taiwan from China, 6–7 ka, where rice-farming originated, and remained distinct from the indigenous Taiwanese population until after the subsequent dispersal into ISEA.

Protecting the health of streams and rivers requires identifying ecologically significant attributes of the natural flow regime. Streamflow regimes are routinely quantified using a plethora of hydrologic metrics (HMs), most of which have unknown relevance to biological communities. At regional and national scales, we evaluated which of 509 commonly used HMs were associated with biological indicators of fish and invertebrate community integrity. We quantified alteration of each HM by using statistical models to predict site-specific natural baseline values for each of 728 sites across the USA where streamflow monitoring data were available concurrent with assessments of invertebrate or fish community integrity. We then ranked HMs according to their individual association with biological integrity based on random forest models that included HMs and other relevant covariates, such as land cover and stream chemistry. HMs were generally the most important predictors of biological integrity relative to the covariates. At a national scale, the most influential HMs were measures of depleted high flows, homogenization of flows, and erratic flows. Unique combinations of biologically relevant HMs were apparent among regions. We discuss the implications of our findings to the challenge of selecting HMs for streamflow research and management.

The natural flow regime is critical to the health of riverine ecosystems. Many hydrologic metrics (HMs) have been developed to describe natural flow regimes, quantify flow alteration, and provide the hydrologic foundation for the development of environmental flow standards. Many applications require the use of models to predict expected natural values of HMs from basin characteristics at sites with no observed records of unimpaired flows. However, the error associated with HM estimation has not been evaluated. The primary goal of our study was to provide guidance for river scientists and managers in the selection, use, and interpretation of HMs for stream classification and hydroecological investigations of river ecosystems. We evaluated the predictability of a broad suite of HMs for the conterminous USA based on random forest statistical models. We also examined how the predictability of metrics varied among unique components of the flow regime. Roughly 40% of 612 HMs we examined could be predicted reliably from basin characteristics. The predictable metrics were disproportionately represented in 5 flow components: asymmetry, seasonality, magnitude, variability, and average monthly flows. Most metrics that represent extreme hydrological events (i.e., high and low flows) could not be reliably predicted. Roughly ⅔ of the evaluated HMs were incalculable or highly biased at intermittent/ephemeral streams because of the need for logarithmic transformations or scaling by other HMs, such as mean flows or percentile flow thresholds. Scaling metrics by drainage area tended to improve predictability. We recommend that the predictability of HMs be given greater consideration in studies and applications in which they are used to characterize and assess alteration of streamflow regimes.

The origins of Ashkenazi Jews remain highly controversial. Like Judaism, mitochondrial DNA is passed along the maternal line. Its variation in the Ashkenazim is highly distinctive, with four major and numerous minor founders. However, due to their rarity in the general population, these founders have been difficult to trace to a source. Here we show that all four major founders, ~40% of Ashkenazi mtDNA variation, have ancestry in prehistoric Europe, rather than the Near East or Caucasus. Furthermore, most of the remaining minor founders share a similar deep European ancestry. Thus the great majority of Ashkenazi maternal lineages were not brought from the Levant, as commonly supposed, nor recruited in the Caucasus, as sometimes suggested, but assimilated within Europe. These results point to a significant role for the conversion of women in the formation of Ashkenazi communities, and provide the foundation for a detailed reconstruction of Ashkenazi genealogical history. Ashkenazi mitochondrial DNA variation has four major founders whose sources are difficult to trace due to the rarity of Ashkenazi Jews in the general population. Here, the authors provide evidence that all four major founders originated from Europe and provide a genealogical record of the Ashkenazi.

Purpose The objective of this study is to evaluate the longitudinal construct validity of the Health Utilities Index Mark 2 (HUI2) and Health Utilities Index Mark 3 (HUI3) using a convergent/divergent validity approach in patients recovering from hip fracture, with the Functional Independence Measure (FIM) as the comparator. Methods A total of 278 patients with a primary diagnosis of hip fracture were interviewed 3–5 days after surgery and then at 1 and 6 months using the HUI2, HUI3 and the FIM and a Likert-type rating of hip pain. A priori hypotheses were formulated. Convergent and divergent correlations between HUI2, HUI3 and FIM change scores for the baseline to 1-month and baseline to 6-month intervals were examined. Results Overall HUI2 detected continued gain in health-related quality of life between 1 and 6 months after fracture, as the change increased from 0.20 to 0.29 units. The correlation between change in the overall HUI2 score and total FIM score was moderate (r = 0.50) over the 6-month interval, but larger than the observed correlation over the 1-month interval (r = 0.36). The correlation between change in overall HUI3 score and total FIM over the 1-month interval was small (r = 0.32), and the correlation between change in overall HUI3 score and total FIM was moderate (r = 0.37) over the 6-month interval. All hypotheses for the divergent correlations were supported. Conclusions Weaker correlations were reported for change over 1 month as compared to change over the 6 months after fracture. Findings supported the longitudinal construct validity of the overall HUI2 and HUI3 for the assessment of recovery following hip fracture, particularly for change over the 6 months following fracture.