Statistical models for estimating absolute densities of field populations of animals have been widely used over the last century in both scientific studies and wildlife management programs. To date, two general classes of density estimation models have been developed: models that use data sets from capture–recapture or removal sampling techniques (often derived from trapping grids) from which separate estimates of population size (NÌ‚) and effective sampling area (AÌ‚) are used to calculate density (DÌ‚ = NÌ‚/AÌ‚); and models applicable to sampling regimes using distance‐sampling theory (typically transect lines or trapping webs) to estimate detection functions and densities directly from the distance data. However, few studies have evaluated these respective models for accuracy, precision, and bias on known field populations, and no studies have been conducted that compare the two approaches under controlled field conditions. In this study, we evaluated both classes of density estimators on known densities of enclosed rodent populations. Test data sets (n = 11) were developed using nine rodent species from capture–recapture live‐trapping on both trapping grids and trapping webs in four replicate 4.2‐ha enclosures on the Sevilleta National Wildlife Refuge in central New Mexico, USA. Additional “saturation” trapping efforts resulted in an enumeration of the rodent populations in each enclosure, allowing the computation of true densities. Density estimates (DÌ‚) were calculated using program CAPTURE for the grid data sets and program DISTANCE for the web data sets, and these results were compared to the known true densities (D) to evaluate each model's relative mean square error, accuracy, precision, and bias. In addition, we evaluated a variety of approaches to each data set's analysis by having a group of independent expert analysts calculate their best density estimates without a priori knowledge of the true densities; this “blind” test allowed us to evaluate the influence of expertise and experience in calculating density estimates in comparison to simply using default values in programs CAPTURE and DISTANCE. While the rodent sample sizes were considerably smaller than the recommended minimum for good model results, we found that several models performed well empirically, including the web‐based uniform and half‐normal models in program DISTANCE, and the grid‐based models Mb and Mbh in program CAPTURE (with AÌ‚ adjusted by species‐specific full mean maximum distance moved (MMDM) values). These models produced accurate DÌ‚ values (with 95% confidence intervals that included the true D values) and exhibited acceptable bias but poor precision. However, in linear regression analyses comparing each model's DÌ‚ values to the true D values over the range of observed test densities, only the web‐based uniform model exhibited a regression slope near 1.0; all other models showed substantial slope deviations, indicating biased estimates at higher or lower density values. In addition, the grid‐based DÌ‚ analyses using full ...

A fully continuous process including an asymmetric hydrogenation reaction operating at 70 bar hydrogen, aqueous extraction, and crystallization was designed, developed, and demonstrated at pilot scale. This paper highlights safety, quality, and throughput advantages of the continuous reaction and separations unit operations. Production of 144 kg of product was accomplished in laboratory fume hoods and a laboratory hydrogenation bunker over two continuous campaigns. Maximum continuous flow vessel size in the lab hoods was 22 L glassware, and maximum plug flow tube reactor (PFR) size in the bunker was 73 L. The main safety advantages of running the hydrogenation reaction continuous rather than batch were that the flow reactor was smaller for the same throughput and, more importantly, the tubular hydrogenation reactor ran 95% liquid filled at steady state. Therefore, the amount of hydrogen in the reactor at any one time was less than that of batch. A two-stage mixed suspension–mixed product removal (MSMPR) cascade was used for continuous crystallization. Impurity rejection by continuous crystallization was superior to that by batch because scalable residence time and steady-state supersaturation enabled robust and repeatable control of enantiomer rejection in a kinetic regime, although this is a nonstandard approach, debatable as an impurity control strategy. The fully continuous wet-end process running in a laboratory infrastructure achieved the same weekly throughput that would be expected from traditional batch processing in a plant module with 400 L vessels.

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Vegetative dormancy, that is the temporary absence of aboveground growth for ≥ 1 year, is paradoxical, because plants cannot photosynthesise or flower during dormant periods. We test ecological and evolutionary hypotheses for its widespread persistence. We show that dormancy has evolved numerous times. Most species displaying dormancy exhibit life-history costs of sprouting, and of dormancy. Short-lived and mycoheterotrophic species have higher proportions of dormant plants than long-lived species and species with other nutritional modes. Foliage loss is associated with higher future dormancy levels, suggesting that carbon limitation promotes dormancy. Maximum dormancy duration is shorter under higher precipitation and at higher latitudes, the latter suggesting an important role for competition or herbivory. Study length affects estimates of some demographic parameters. Our results identify life historical and environmental drivers of dormancy. We also highlight the evolutionary importance of the little understood costs of sprouting and growth, latitudinal stress gradients and mixed nutritional modes.

The design, development, and implementation of a pilot-scale continuous Schotten−Baumann amide bond formation and reactive crystallization to afford LY2886721 is described. The material met all API quality attributes and was comparable to material produced by a defined batch process. The scalability of the reaction and crystallization processes was confirmed during the development process. The pilot-scale equipment set was contained in a walk-in fume hood and operated at a production rate of 3 kg/day in a 72 h continuous run. Significant technical and business drivers for running the process in continuous flow mode were proposed and examined during development. The continuous process provided for lab hood commercialization and provided for minimal material at risk in the process. The demonstration also confirmed the risk inherent to operation of a tubular reactor under supersaturated conditions, and fouling occurred in the plug flow reactor. Fouling also occurred in the crystallizer. Recognizing these deficiencies, the process operated within the footprint of a standard walk-in fume hood, providing a successful demonstration of the opportunities afforded by continuous processing for low volume pharmaceuticals.