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Biodiversity can stabilise productivity through different mechanisms, such as asynchronous species responses to environmental variability and species stability. Global changes, like intensified drought, could negatively affect species richness, species asynchrony and species stability, but it is unclear how changes in these mechanisms will affect the stability of above‐ground primary productivity (ANPP) across ecosystems. We studied the effects of a 4‐year extreme drought on ANPP stability and the underlying mechanisms (species richness, species asynchrony and species stability) across six grasslands in Northern China. We also assessed the relative importance of these mechanisms in determining ANPP stability under extreme drought. We found that extreme drought decreased ANPP stability, species richness, species asynchrony and species stability across the six grasslands. However, structural equation modelling revealed that species asynchrony, not species richness or species stability, was the most important mechanism promoting stability of ANPP, regardless of drought across the six grasslands. Synthesis. Our results suggest that species asynchrony, not species richness and species stability, consistently buffers ecosystem stability against extreme drought across and within grasslands spanning a broad precipitation gradient. Thus, species asynchrony may be a more general mechanism for promoting stability of ANPP in grasslands in the face of intensified drought.

Mass spectrometry (MS) is used to monitor chemical reactions in droplets. In almost all cases, such reactions are accelerated relative to the corresponding reactions in bulk, even after correction for concentration effects, and they serve to predict the likely success of scaled-up reactions performed in microfluidic systems. The particular chemical targets used in these test studies are diazepam, atropine and diphenhydramine. In addition to a yes/no prediction of whether scaled-up reaction is possible, in some cases valuable information was obtained that helped in optimization of reaction conditions, minimization of by-products, and choice of catalyst. In a variant on the spray-based charged droplet experiment, the Leidenfrost effect was used to generate larger, uncharged droplets and the same reactions were studied in this medium. These reactions were also accelerated but to smaller extents than in microdroplets, and they gave results that correspond even more closely to microfluidics data. The fact that MS was also used for online reaction monitoring in the microfluidic systems further enhances the potential role of MS in exploratory organic synthesis.

In generalized estimating equations (GEE), the correlation between the repeated observations on a subject is specified with a working correlation matrix. Correct specification of the working correlation structure ensures efficient estimators of the regression coefficients. Among the criteria used, in practice, for selecting working correlation structure, Rotnitzky-Jewell, Quasi Information Criterion (QIC) and Correlation Information Criterion (CIC) are based on the fact that if the assumed working correlation structure is correct then the model-based (naive) and the sandwich (robust) covariance estimators of the regression coefficient estimators should be close to each other. The sandwich covariance estimator, used in defining the Rotnitzky-Jewell, QIC and CIC criteria, is biased downward and has a larger variability than the corresponding model-based covariance estimator. Motivated by this fact, a new criterion is proposed in this paper based on the bias-corrected sandwich covariance estimator for selecting an appropriate working correlation structure in GEE. A comparison of the proposed and the competing criteria is shown using simulation studies with correlated binary responses. The results revealed that the proposed criterion generally performs better than the competing criteria. An example of selecting the appropriate working correlation structure has also been shown using the data from Madras Schizophrenia Study.

In this investigation, incorporation of silica into natural rubber (NR)-reclaim rubber (RR) blend system was carried out by sol-gel technique at various sol-gel reaction temperatures. The effect of RR on silica reinforcement, hitherto unexplored, was studied for different NR/RR blend systems. The degree of reinforcement of sol-gel vulcanizates by equilibrium swelling method indicates that the reinforcing efficiency of the in situ generated silica by sol-gel technique increases with increasing reclaim rubber content. The reinforcing efficiency, tensile properties and thermal stability of sol gel vulcanizates (SGV) prepared at 508C become maxima as compared to SGV prepared at 308C and 708C. The amount of silica incorporated by sol-gel technique was determined by thermogravimetry analysis. It indicates that the thermal stability increases with silica content. Attenuated total reflection study indicates that RR forms bond with silica particles due to the presence of active functional site on RR. Scanning electron microscopy studies further indicate the coherency and homogeneity in the silica filled NR/RR vulcanizates. The microwave diagnosis of different SGVs was also carried out and the frequency dependence of dielectric permittivity (E 0 ) and loss (E 00 ) were measured. POLYM. ENG. SCI.

The use of rice husk as a low cost adsorbent for the removal of copper from wastewater has been explored in a laboratory scale experiment. The rice husk used for the study was treated with alkali to increase the sorption properties. The influence of metal ion concentration, weight of biosorbent, stirring rates, temperature and pH were also evaluated, and the results are fitted using adsorption isotherm models. From the experimental results it was observed that almost 90-98% of the copper could be removed using treated rice husk. The Langmuir adsorption isotherm, Freundlich isotherm and Tempkin isotherm models were used to describe the distribution of copper between the liquid and solid phases in batch studies, and it was observed that the Langmuir isotherm better represented the adsorption phenomenon. The experimental rate constant, activation energy, Gibbs free energy, enthalpy and entropy of the reaction were calculated in order to determine the mechanism of the sorption process.

Individuals adapt to changes in their environment, such as food availability and temperature, by adjusting the amount of time spent in different behavioral activities. These adjustments in behavior should vary across age-sex class according to specific physiological and social needs. We studied the activity budgets of three social Japanese macaque groups inhabiting either vegetated or nonvegetated enclosures in order to compare the effects of access with vegetation, as both food and substrate on resting, feeding, grooming and moving activities over a 12-month period. Daily access to natural foods for monkeys in the vegetated enclosure seems to be largely responsible for the differences in daily time budgets of these three groups. Resting time in all three groups was longer than the time devoted to other activities. Resting and moving time in the two nonvegetated enclosures was significantly longer than in the vegetated enclosure. In contrast, feeding and grooming time was significantly longer in the vegetated enclosure. Seasonal variation in time spent feeding, resting and grooming was significantly effected by enclosure type. In all three enclosures, immatures, particularly females, spent more time feeding and moving, whereas adults spent more time resting. Significant monthly variation in time spent by age-sex class was noted only for feeding and resting. Interestingly, in the vegetated enclosure, time spent feeding on natural vegetation was equal to the amount of time spent feeding on provisioned food. This suggests that factors other than energetic and nutritional needs may be important determinants of the activity budget of the species. These results have important implications for the enrichment of captive primates and our understanding of the maintenance of activity patterns by primates in the wild.

Objective: Underdiagnosis of COPD is widespread, at least in part due to underuse of spirometry. Symptom-based questionnaires may be helpful as an adjunct to spirometry. The aim of this study was to determine which types of questions might aid in identifying COPD. Methodology: Questionnaires were identified by literature review and input from a multinational advisory board of primary care providers. Questions were placed into groups and evaluated with respect to their ability to perform in two scenarios: (i) to identify persons with COPD from a general population (Case-finding scenario); and (ii) to distinguish persons with COPD from those with asthma (Differential Diagnosis scenario). Questions were retrospectively validated using the Third National Health and Nutrition Examination Survey data. Potential predictive ability was examined in bivariate and multivariate frameworks. Results: Four published question sets and six additional documents were included. There was agreement in the use of smoking and symptom-based questions, but important differences in the use of demographic, personal history and other information. Most question types had significant bivariate relationships with airway obstruction. In multivariate analysis, age, BMI, smoking status and pack-years, symptoms (cough, phlegm, dyspnoea, wheeze), and prior diagnosis consistent with asthma or COPD all showed significant ability to discriminate between persons with and without obstruction in a general population. Conclusion: Simple self-administered questionnaires can be used to identify persons for whom spirometric testing may be especially appropriate. Development of such questionnaires will require additional study, including prospective validation of items in an appropriate clinical setting and policy recommendations on the use of these tools.

Microtrichomanes, a controversial genus created originally to accommodate "intermediates" between Hymenophyllum and Trichomanes, was reassessed using molecular data in order to clarify the systematic position of the species assigned to it. The results strongly suggest a polyphyletic origin for Microtrichomanes, with most of the species being placed in Hymenophyllum s.l., in spite of their having the cup-shaped involucre which is the primary taxonomic character of Trichomanes s.l. Based on this result, some new combinations are made herein for the species formerly attributed to Microtrichomanes; and an updated dichotomous key and synonymic lists are provided.

The ground state microwave rotational spectrum of allyl isocyanate (H2CCHCH2NCO) in the frequency range 12.4-26.0 GHz is reported. Analysis of a-type R-branch transitions gives the rotational constants A = 8019.78 MHz, B = 2088.85 MHz, and C = 1757.40 MHz. The assigned transitions are consistent with the C-gauche conformer of the molecule having the NCO group cis with respect to the CC bond.

The microwave spectrum of deuterated 3-fluorophenol, 3-FC 6 H 4 OD, has been observed in the frequency ranges 12.5–18.0 GHz ( KU band) and 21.5–25.0 GHz ( K band) in the ground vibrational state at room temperature. Analysis yields three rotational and five quartic centrifugal distortion constants: A = 3742.943 ± 0.029, B = 1737.449 ± 0.017, C = 1186.728 ± 0.016, d j = (7.383 ± 2.0) X 10 −4 , d JK = (−13.756 ± 3.191) × 10 −3 , d K = (−17.814 ± 4.298) × 10 −3 , d WJ = (−4.0 ± 1.0) × 10 −7 , d WK = (9.3 ± 2.2) × 10 −6 (in MHz). From a consideration of the r s coordinate of the H atom in the OH group, the present analysis leads to the assignment of the observed spectrum to the trans conformer of the molecule. An r o structure satisfying the rotational constants of both the parent and the deuterated species is proposed. The small value of the inertia defect, Δ = −0.0368, confirms the planarity of the molecule.