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1.
Traditional approaches for managing aquatic resources have often failed to account for effects of anthropogenic disturbances on biota that are not directly reflected by chemical and physical proxies of environmental condition. The index of biotic integrity (IBI) is a potentially effective assessment method to integrate ecological, functional, and structural aspects of aquatic systems. A macrophyte-based IBI was developed for Minnesota lakes to assess the ability of aquatic plant communities to indicate environmental condition. The index was developed using quantitative point intercept vegetation surveys for 97 lakes that represent a range of limnological and watershed characteristics. We followed an approach similar to that used in Wisconsin to develop the aquatic macrophyte community index (AMCI). Regional adaptation of the AMCI required the identification of species representative of macrophyte communities in Minnesota. Metrics and scaling methods were also substantially modified to produce a more empirically robust index. Regression analyses indicated that IBI scores reflected statewide differences in lake trophic state (R2 = 0.57, F = 130.3, df = 1, 95, p < 0.005), agricultural (R2 = 0.51, F = 83.0, df = 1, 79, p < 0.005), urban (R2 = 0.22, F = 23.0, df = 1, 79, p < 0.005), and forested land uses (R2 = 0.51, F = 84.7, df = 1, 79, p < 0.005), and county population density (R2 = 0.14, F = 16.6, df = 1, 95, p < 0.005). Variance partitioning analyses using multiple regression models indicated a unique response of the IBI to human-induced stress separate from a response to natural lake characteristics. The IBI was minimally affected by differences in sample point density as indicated by Monte Carlo analyses of reduced sampling effort. Our analysis indicates that a macrophyte IBI calibrated for Minnesota lakes could be useful for identifying differences in environmental condition attributed to human-induced stress gradients.  相似文献   

2.
The study investigated the suitability of stage of maturity and botanical fractions of whole crop rice (WCR) to predict yield and nutritive value of ensiled WCR for dairy cows. Eight varieties of WCR (i.e., Akichikara, Fukuhibiki, Habataki, Hamasari, Hokuriku 168, Kusanami, Tamakei 96, Yumetoiro) were harvested at four stages of maturity (i.e., 10, 22, 34, 45 days after flowering [DAF]) and ensiled. Dry matter (DM) yield at each harvest was determined. Silage samples were fractionated into four botanical fractions being: leaf blade, leaf sheath, stem and head. Silage samples were also analyzed for chemical composition, fermentation characteristics, in situ DM and N disappearance. Metabolizable energy (ME) and metabolizable protein (MP) content of samples were estimated according to Terada et al. (1988) and AFRC (1993), respectively. Relationships between maturity or proportions of botanical fractions and contents of WCR silage in terms of DM, ME and MP, and their yields, were estimated by correlation and regression analysis. Stage of maturity was positively related (P<0.001) to ME content (R2 = 0.46; y = 4.53 + 0.08X) and MP content (R2 = 0.56; y = 22.26 + 0.76X), and DM yield (R2 = 0.63; y = 9.21 + 0.12X), ME yield (R2 = 0.68, y = 36931 + 1708X) and MP yield (R2 = 0.72, y = 161.0 + 14.15X) of WCR. Proportion of leaf was negatively related to yields and nutritive value of ensiled WCR, whilst proportion of head was positively related (P<0.05 to <0.001). Proportion of head was best related to the ME content (R2 = 0.72; y = 3.26 + 0.009X), MP content (R2 = 0.72; y = 12.31 + 0.079X), and DM yield (R2 = 0.41; y = 9.02 + 0.009X), ME yield (R2 = 0.76, y = 19494 + 165.5X), and MP yield (R2 = 0.75, y = 34.37 + 1.32X) of WCR. Results suggest that to optimize yield and nutritive value, WCR should be ensiled within 40 DAF and the proportion of head should be equal to or more than 500 g per kg DM of WCR silage. Stage of maturity and proportion of head of WCR predict yields of DM, ME and MP of WCR, and their contents, in WCR silage with acceptable accuracy. However, these relationships need to be validated using large data sets and in vivo studies.  相似文献   

3.
The purpose of the present study was to examine the patterns of responses for torque, electromyographic (EMG) amplitude, EMG mean power frequency (MPF), mechanomyographic (MMG) amplitude, and MMG MPF across 30 repeated maximal isometric (ISO) and concentric (CON) muscle actions of the leg extensors. Twelve female subjects (21.1 ± 1.4 yrs; 63.3 ± 7.4 kg) performed ISO and CON fatigue protocols with EMG and MMG signals recorded from the vastus lateralis. The relationships for torque, EMG amplitude, EMG MPF, MMG amplitude, and MMG MPF versus repetition number were examined using polynomial regression. The results indicated there were decreases (p < 0.05) across the ISO muscle actions for torque (r2 = 0.95), EMG amplitude (R2 = 0.44), EMG MPF (r2 = 0.62), and MMG MPF (r2 = 0.48), but no change in MMG amplitude (r2 = 0.07). In addition, there were decreases across the CON muscle actions for torque (R2 = 0.97), EMG amplitude (R2 = 0.46), EMG MPF (R2 = 0.86), MMG amplitude (R2 = 0.44), and MMG MPF (R2 = 0.80). Thus, the current findings suggested that the mechanisms of fatigue and motor control strategies used to modulate torque production were similar between maximal ISO and CON muscle actions.  相似文献   

4.
A small library of N-benzyl indolequinuclidinone (IQD) analogs has been identified as a novel class of cannabinoid ligands. The affinity and selectivity of these IQDs for the two established cannabinoid receptor subtypes, CB1 and CB2, was evaluated. Compounds 8 (R = R2 = H, R1 = F) and 13 (R = COOCH3, R1 = R2 = H) exhibited high affinity for CB2 receptors with Ki values of 1.33 and 2.50 nM, respectively, and had lower affinities for the CB1 receptor (Ki values of 9.23 and 85.7 nM, respectively). Compound 13 had the highest selectivity of all the compounds examined, and represents a potent cannabinoid ligand with 34-times greater selectivity for CB2R over CB1R. These findings are significant for future drug development, given recent reports demonstrating beneficial use of cannabinoid ligands in a wide variety of human disease states including drug abuse, depression, schizophrenia, inflammation, chronic pain, obesity, osteoporosis and cancer.  相似文献   

5.
The effect of different overwintering temperatures (2.5 ± 1 °C in a refrigerator or outdoor natural overwintering on wet topsoil with weak frosts) on the freezing temperature and survival rate of turions of 10 aquatic plant species with different ecological traits (free-floating habit or bottom rooting) was studied using mini thermocouples. Dormant, non-hardened turions of 9 species exhibited freezing within a narrow temperature range of ?7.0 to ?10.2 °C, while Hydrocharis morsus-ranae froze at ?3.6 °C. The survival rate of the turions after the measurements was, however, very low (0–38%). In several species, the freezing temperature of turions at the beginning of germination was not significantly different (at p < 0.05) from the dormant ones. The mean freezing temperature of outdoor hardened turions of 6 species was within a very narrow range of ?2.8 to ?3.3 °C and was thus significantly higher by 4–7 °C (p < 0.0002) than that for the non-hardened turions. It is assumed that the freezing temperatures indicate freezing of the extracellular water. The hardened turions of all 7 species were able to survive mild winter frosts under the topsoil conditions at a rate of 76–100%. These characteristics suggest that the turions of aquatic species can be hardened by weak frosts and that their frost hardiness is based on the shift from frost avoidance in non-hardened turions to frost tolerance.  相似文献   

6.
《Inorganica chimica acta》2006,359(11):3549-3556
A series of cationic trispyrazolylmethane complexes of the general form [TmRM(CH3CN)3]2+ (Tm = tris(pyrazolyl)methane, 1, R = 3,5-Me2, M = Fe(II); 2, R = 3-Ph, M = Fe(II); 3, R = 3,5-Me2, M = Co(II); 4, R = 3-Ph, M = Co(II)) with ‘piano-stool’ structures was prepared by the reaction of the N3tripodal ligands (TmR)with [(CH3CN)6M](BF4)2 in a 1:1 stoichiometric ratio. Magnetic susceptibility measurements indicate that all four complexes with BF4 counter anions are paramagnetic, high-spin systems in the solid state with μeff at high temperatures of 5.2 (1, S = 2), 5.4 (2, S = 2), 4.9 (3, S = 3/2) and 4.6 (4, S = 3/2) BM, respectively. Comparisons of bond lengths from the metal centre to the TmR nitrogen donors, and from the metal centre to the acetonitrile nitrogen donors indicate that the neutral tripodal ligands appear to be more weakly coordinated to the metal centre than are the acetonitrile ligands. Reactions of these tripodal complexes with bidentate phosphine ligands, such as 1,2-diphosphinoethane or 1,2-bis(diallylphosphino)ethane leads to displacement of the tripodal ligand, or to the formation of more thermally stable bis-ligand complexes M(TmR)2 (R = 3,5-dimethyl).  相似文献   

7.
This study aimed to determine the sensorimotor strategies privileged by mountain bikers (MTB) and road cyclists (RC) for balance control. Twenty-four MTB and 24 RC (off-road Olympics, world, continental and national champions, Tour-de-France participants, on-road world cup race winner) volunteered to answer a questionnaire about the characteristics of cycling practice and perform a sensory organization test, aiming to evaluate balance control in 6 different sensory situations based upon visual and support surface perturbations (C1ES to C6ES). RC balance performances were better than those of MTB both during quiet stance eyes opened (C1ES, p = 0.011) and when only somatosensory information is disrupted (C4ES, p = 0.039), highlighting a higher use of vision to control balance in RC. Moreover, a positive correlation was shown in the whole population (MTB + RC) between the visual ratio (RVIS = C4ES/C1ES) and the proportion of riding distance of on-road cycling (ρ = 0.28, p = 0.054). In MTB, the use of proprioception (somatosensory ratio: RSOM = C2ES(eyes closed)/C1ES) was increased by a higher intensity of off-road cycling (ρ = 0.49, p = 0.018) and that of vision (RVIS) by a higher intensity of on-road cycling (ρ = 0.41, p = 0.048). The difference in sensory organization between MTB and RC could be explained by adaptive processes elaborated from environmental stimulations and technical specificities of these disciplines.  相似文献   

8.
Activated organophosphate (OP) insecticides and chemical agents inhibit acetylcholinesterase (AChE) to form OP-AChE adducts. Whereas the structure of the OP correlates with the rate of inhibition, the structure of the OP-AChE adduct influences the rate at which post-inhibitory reactivation or aging phenomena occurs. In this report, we prepared a panel of β-substituted ethoxy and γ-substituted propoxy phosphonoesters of the type p-NO2PhO-P(X)(R)[(O(CH2)nZ] (R = Me, Et; X = O, S; n = 2, 3; Z = halogen, OTs) and examined the inhibition of three AChEs by select structures in the panel. The β-fluoroethoxy methylphosphonate analog (R = Me, Z = F, n = 2) was the most potent anti-AChE compound comparable (ki ~6 × 106 M?1 min?1) to paraoxon against EEAChE. Analogs with Z = Br, I, or OTs were weak inhibitors of the AChEs, and methyl phosphonates (R = Me) were more potent than the corresponding ethyl phosphonates (R = Et). As expected, analogs with a thionate linkage (PS) were poor inhibitors of the AChEs.  相似文献   

9.
Agricultural intensification is altering biodiversity patterns worldwide. Rapid and effective methods are needed to monitor these changes in farmland biodiversity, but it becomes both a cost- and time-prohibitive task, particularly for hyper-diverse groups such as arthropods. We evaluated the effectiveness of surrogates in irrigated and rainfed wheat fields in a Mediterranean farmland in NW Spain in order to get a rapid tool to assess arthropod biodiversity. We studied six groups with different ecological needs (i.e. Aphididae, Aphidiinae, Coccinellidae, Formicidae, Heteroptera and Syrphidae) at species level (147 species), genus (105), family (10, only Heteroptera) and order (19) level. Higher taxa, cross-taxa and subset-taxa or total richness approaches were tested as well as the correlation in composition between levels for the selected groups, and the influence of farming regime. Genus richness was a good surrogate of species richness in all six groups studied (R2 = 0.38–0.60), like family and order were for Heteroptera (R2 = 0.37 and 0.29, respectively). Cross-taxa analyses showed that Aphididae and Aphidiinae genera (R2 = 0.19 and 0.30, respectively) and species (R2 = 0.20 and 0.28, respectively) were good surrogates for Aphidiinae and Aphididae species respectively. Coccinellidae genera (R2 = 0.26) and species (R2 = 0.25) were good surrogates for Heteroptera species. Finally, Aphididae and Coccinellidae both at genera (R2 = 0.14 and 0.20, respectively) and at species levels (R2 = 0.12–0.22, respectively) were good surrogates for total species richness of all groups. Genera composition was the best surrogate for the species composition within each group. Farming regime had no influence on the relationships between surrogates and species patterns in most cases. Our results suggest that genera level is a useful surrogate for all the studied groups and family is appropriate for Heteroptera. Genus level provided a saving of 15% of identification time in Aphididae and 80% for Coccinellidae. This proves its usefulness to asses and monitor biodiversity in wheat croplands and the possibility to reduce costs.  相似文献   

10.
An experiment was conducted to study the rumen digestion characteristics of whole feeds (WF) and the neutral detergent fibre (aNDF) and neutral detergent soluble (NDS) fractions of a range of starch-rich feeds using an automated in vitro gas production (GP) technique. In addition, the ruminal digestibility values predicted from the GP data were compared to previously acquired in vivo data. Nine feeds with starch concentrations ranging from 389 to 712 g/kg dry matter and with known in vivo digestibilities were subjected to neutral detergent extraction. The GP for each WF and the corresponding aNDF fractions were measured in duplicate in buffered rumen fluid during 72 h on two occasions. The fermentation residues were collected and analyzed for aNDF concentration to estimate their true organic matter (OM) and NDF digestibility. The GP from the NDS fraction was calculated by subtracting the GP from the aNDF fraction from the GP of the WF. A three-pool Gompertz model was fitted to the GP profiles (R2 = 0.99) and a two compartment, mechanistic and dynamic rumen model was used to predict the digestibility of the potentially digestible feed fraction and the effective digestion rate (kd). The true OM and NDF digestibility determined for the WF ranged from 0.804 to 1.011 and from 0.362 to 1.107, respectively. The NDF digestibility determined for the aNDF fraction ranged from 0.410 to 0.985. The effective kd values estimated using GP data varied from 0.118 to 0.282/h for the WF and from 0.123 to 0.301/h for the NDS fraction, and were less (P<0.05) for maize compared to small grains (SG) but did not differ between barley and wheat (P>0.05). The effective kd values for the aNDF fraction ranged from 0.039 to 0.082/h and did not differ (P>0.05) either between maize and SG or between barley and wheat. The predicted ruminal NDS digestibility determined using GP data closely matched the in vivo data describing starch digestion (R2 = 0.81). The effective kd values for the WF were strongly related (R2 = 0.94) to those for the NDS fractions. The results indicate that when measured with the GP technique, the differences in the digestion characteristics of maize and small grains are less than those previously reported in studies using the in situ method. It is concluded that the predicted NDS digestibility determined using GP data corresponded well to the in vivo starch digestibility. Our results also suggest that the first order digestion rates of NDS (starch) in starch-rich feeds can be accurately determined by incubating WF samples in the GP system and using the GP kinetic data in a dynamic, mechanistic rumen model.  相似文献   

11.
We explored the relationships between surface-soil (1–20 cm) organic carbon isotopic signatures and associated climatic factors in central-east Asia in an attempt to develop transfer functions that can be used to retrieve the paleoclimatic information stored in the thick eolian–paleosol sequences within the area. Our analysis shows that the negative correlation between the surface-soil organic δ13C values and the mean annual precipitation is robust (R2 = 0.453; n = 196; p < 0.05) and the negative correlation with the growing-season (April–September) precipitation is more significant (R2 = 0.4966; n = 196; p < 0.05). Our study further shows that the positive correlation between the surface-soil organic δ13C values and mean growing-season aridity is most significant (R2 = 0.5805; n = 196; p < 0.05). We have smoothed both the organic δ13C values and the mean growing-season aridity values using a 3-point moving-window average-filter method in an attempt to remove some of random errors and found that the positive correlation between the two is further increased (R2 =  0.7784; n =  192; p < 0.05). These robust linear relationships demonstrate their value in reconstructing paleoclimate changes in the study area. The documented climatic dependency of the surface-soil carbon isotopic composition in the study area might have resulted both from the humidity-related isotopic enrichment processes of the dominant C3 plants (stomatal conductance and photosynthetic discrimination) and from the aridity-related abundance of C4 plants (mainly Chenopodiaceae species) along the S–N bioclimatic gradient.  相似文献   

12.
There has been less understanding of relations of microbial community patterns with plant diversity in constructed wetlands. We conducted a single full-scale subsurface vertical flow constructed wetland (SVFCW, 1000 m2) study focusing on domestic wastewater processing. This study measured the size and structure of microbial community using fumigation extraction and BIOLOG Ecoplate? techniques, to examine the effects of macrophyte diversity on microbial communities that are critical in treatment efficiency of constructed wetlands. We also determined the relationship of plant diversity (species richness) with its biomass production under disturbance of the same wastewater supply. Linear regression analysis showed that plant biomass production strongly correlated with plant species richness (R = 0.407, P < 0.001). Increase in plant species richness increased microbial biomass carbon and nitrogen (R = 0.494, P < 0.001; R = 0.465, P < 0.001) and utilization of amino acids on Ecoplates (R = 0.235, P = 0.03), but limited the utilization of amine/amides (R = ?0.338, P = 0.013). Principal components analysis (PCA) showed that the diversity and community-level physiological profiles (CLPP) of microbial community at 168 h of incubation strongly depended on the presence or absence of plant species in the SVFCW system, but not on the species richness. This is the first step toward understanding relations of plant diversity with soil microbial community patterns in constructed wetlands, but the effect of species diversity on microbial community should be further studied.  相似文献   

13.
《Small Ruminant Research》2009,85(1-3):41-46
Data on linear body measurements (LBM) of 403 sheep collected in three areas of KwaZulu-Natal were utilized to develop a prediction equation for live body weight of Zulu sheep. Data were collected on live weight (LW), heart girth (HG), wither height (WH) and scrotum circumference (SC) on sheep of all ages. The age of sheep was estimated by dentition. The analysis of variance showed that age and sex were important factors contributing to variation in LW of Zulu sheep. Phenotypic correlation coefficients and regression equations of LW on HG, WH and SC were computed within different age groups (milk set of teeth, one pair, two pairs and the three and four pairs of incisors). Low correlation coefficients (r = 0.21–0.48) between LW, HG and WH were found among the pregnant ewes. The relationship between LBM and LW was stronger (r = 0.66–0.86) for males than among females (r = 0.42–0.75). The cubic polynomial of HG was the best fit (R2 = 0.76) for the live weight prediction of young sheep with milk set of teeth. The combination of HG and WH produced the best fit for the two tooth and above males and non-pregnant females. The LW prediction equations for pregnant females were not reliable (R2 = 0.05–0.26). The SC was more precise (R2 = 0.61–0.80) when estimating the live weight of young males (<15–22-month-old) than of the older rams (R2 = 0.23–0.56). It was concluded that LW of Zulu sheep can be reasonably estimated using the HG and WH. A table could be constructed for the farmers to estimate the LW of their animals.  相似文献   

14.
《Small Ruminant Research》2010,91(1-3):18-26
Accurate estimates of milk production or milk intake are difficult, as all methods interfere to some degree with the natural behaviour of the dam and her young, and potentially alter milk yield itself. The present study compared milk yield obtained by the “oxytocin” method, udder dimensions (UD), the isotope dilution method, and live weight change of the lamb, in an attempt to select the most accurate and convenient way of measuring milk production in non-dairy sheep. In addition, the study investigated which of the three milk-estimation techniques was an accurate predictor of growth rates of lambs. Thirty-seven singleton-bearing and rearing ewes were milked once a week, for seven consecutive weeks, using the “oxytocin” method. Prior to each afternoon milking, the external dimensions of the ewe's udder were measured. Lambs were weighed weekly for the first seven weeks of life and live weight change was calculated. The deuterium oxide (D2O) dilution technique was used to estimate milk intake of the lambs and performed at approximately 7 days post-partum and finishing on approximately day 14. Pearson's correlation coefficients and multiple regression coefficients among techniques were calculated. The UD-models at d7 (R2 = 0.35), d35 (R2 = 0.36) and d42 (R2 = 0.34), were the best models explaining variation in milk yield (concordance correlation coefficient (CCC) = 0.49; 0.53; 0.51; for d7, d35 and d42, respectively). The lamb live weight-change model explained the variation in milk yield best at d28 (R2 = 0.32; CCC = 0.49), at d35 (R2 = 0.22; CCC = 0.36) and at d42 (R2 = 0.28; CCC = 0.44). At d14, the intake of milk by lambs as measured by the D2O technique, did not explain the variation in milk yield. In conclusion, udder dimensions, lamb live weight change and lamb milk intake are relatively poor estimators of the milk yield of singleton-rearing ewes obtained by the “oxytocin” method. Additionally, udder dimensions, milk yield and lamb milk intake do not give an accurate prediction of growth rates of singleton lambs. These results emphasize that there is a difference between ewe milk production potential and lamb milk intake, which need to be considered when estimating milk production in non-dairy animals.  相似文献   

15.
Human disturbance may differentially affect the behavior of wild animals and such behavioral perturbations may have fitness consequences. To understand the effects of specific types of human disturbance on antipredator behavior, a behavior whose performance enhances survival, we studied yellow-bellied marmots (Marmota flaviventris). We quantified both antipredator vigilance and the flight initiation distance of the marmots to an approaching human in six different colony sites where we also quantified the frequency and type of human visitation. We developed an analysis framework, using linear mixed models, and found that: (1) when the presence of motorized vehicles and bicycles was high, marmots increased the proportion of time spent vigilant (pseudo R2 = 0.33 and 0.31 for motorized vehicles and bicycles, P < 0.05) and decreased the time spent foraging (pseudo R2 = 0.29 and 0.23 for motorized vehicles and bicycles, P < 0.05), (2) there was no significant effect of the presence of pedestrians on the time allocated to vigilance and foraging (pseudo R2 = 0.25 and 0.19, P > 0.05), (3) marmots decreased the flight initiation distance as disturbance of motorized vehicles (pseudo R2 = 0.85) and pedestrians (pseudo R2 = 0.84) increased (P < 0.05), and (4) when we considered bicycles as the disturbance, juveniles tolerated closer approaches than adults or yearlings (P < 0.001). Marmots thus responded to some human disturbance by adjusting time spent in foraging and shortening the tolerance distance. Since these behavioral responses could have significant implications for survival and reproduction, we should generally view human disturbance as something that can influence natural antipredator behavior. Importantly, based on an understanding of the differential effects of human activities on wildlife, reducing human disturbance should be taken into account for wildlife management. In addition, our approach will be useful to quantify differential effects of humans on wildlife and to enhance our ability to manage those impacts.  相似文献   

16.
Most biomechanical studies into changing direction focus on final contact (FC), whilst limited research has examined penultimate contact (PEN). The aim of this study was to explore the kinematic and kinetic differences between PEN and FC of cutting and pivoting in 22 female soccer players (mean ± SD; age: 21 ± 3.1 years, height: 1.68 ± 0.07 m, mass: 58.9 ± 7.3 kg). Furthermore, the study investigated whether horizontal force–time characteristics during PEN were related to peak knee abduction moments during FC. Three dimensional motion analyses of cutting and pivoting on the right leg were performed using Qualysis ‘Proreflex’ infrared cameras (240 Hz). Ground reaction forces (GRF) were collected from two AMTI force platforms (1200 Hz) to examine PEN and FC. Both manoeuvres involved significantly (P < 0.05) greater knee joint flexion angles, peak horizontal GRF, but lower average horizontal GRF during PEN compared to FC. Average horizontal GRF during PEN (R = −0.569, R2 = 32%, P = 0.006) and average horizontal GRF ratio (R = 0.466, R2 = 22%, P = 0.029) were significantly related to peak knee abduction moments during the FC of cutting and pivoting, respectively. The results indicate PEN during pre-planned changing direction helps reduce loading on the turning leg where there is greater risk of injuries to knee ligaments.  相似文献   

17.
A series of C-(3-aminomethyl-cyclohexyl)-methylamine derivatives were synthesized and evaluated for their antitubercular activity. Some of the compounds exhibited potent activity against Mycobacterium tuberculosis H37Rv. One of the compound having t-butyl at para position of the benzene ring showed excellent activity even better than the standard drug ethambutol with MIC value 1.1 ± 0.2 μM. The time-kill kinetics study of two most active compounds showed rapid killing of the M. tuberculosis within 4 days. Additionally atom-based quantitative structure–activity relationship (QSAR) model was developed that gave a statistically satisfying result (R2) = 0.92, Q2 = 0.75, Pearson-R = 0.96 and effectively predicts the anti-tuberculosis activity of training and test set compounds.  相似文献   

18.
Realizing the importance of forest carbon monitoring and reporting in climate change, the present study was conducted to derive spectrally modeled aboveground biomass and mitigation using Landsat data in combination with sampled field inventory data in the coniferous forests of Western Himalaya. After conducting preliminary survey in 2009, 90 quadrats (45 each for calibration and validation) of 0.1 ha were laid in six forest types for recording field inventory data viz. diameter at breast height, height, slope and aspect. Biomass carbon (Mg ha 1) was worked out for different forest types and crown density classes (open with 10–40% crown density and closed with > 40% crown density) using recommended volume equations, ratios and factors. Biomass carbon map (aboveground + belowground) was generated for the entire region using geospatial techniques. Normalized difference vegetation index (NDVI) was generated and spectral values were extracted to establish relation (R2 = 0.72, p < 0.01) with the field inventory data. The model developed was validated (R2 = 0.73, p < 0.01) with 45 sample observations not used earlier for predicting and generating biomass carbon map (2009) for the entire region. The data from field based inventory indicates highest total biomass carbon (171.40, σ ± 23.19) Mg ha 1 for Fir–Spruce (closed) which has relatively more mature girth classes and low tree density. This value was found to be significantly higher than other forest types. Lowest biomass carbon was observed for Blue Pine (open) (37.15, σ ± 11.82) Mg ha 1. The NDVI values for the entire region ranged from 0 to 0.62 and consequently the spectrally derived aboveground biomass carbon varied from 0 to 600 Mg ha 1. The study demonstrates the application of mapping, spectral responses and sampled field inventory for type wise assessment of carbon mitigation in temperate coniferous forests of Himalayas.  相似文献   

19.
Samarcandin 1, a natural sesquiterpene-coumarin, was isolated as well as elucidated from F. assa-foetida which has significant effect in Iranian traditional medicine because of its medicinal attitudes. The crystal structure of samarcandin was determined by single-crystal X-ray structure analysis. It is orthorhombic, with unit cell parameters a = 10.8204 (5) Å, b = 12.9894 (7) Å, c = 15.2467 (9) Å, V = 2142.9 (2) Å3, space group P212121 and four symmetry equivalent molecules in the unit cell. Samarcandin was isolated in order to study for its theoretical studies as well as its cellular toxicity as anti-cancer drug against two cancerous cells. In comparison with controls, our microscopic and MTT assay data showed that samarcandin suppresses cancer cell proliferation in a dose-dependent manner with IC50 = 11 μM and 13 for AGS and WEHI-164 cell lines, respectively. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) of the structure was computed by three functional methods and 6-311++G7 standard basis set. The optimized molecular geometry and theoretical analysis agree closely to that obtained from the single crystal X-ray crystallography. To sum up, the good correlations between experimental and theoretical studies by UV, NMR, and IR spectra were found.  相似文献   

20.
This paper reports development and implementation of superior fermentation strategies for β-galactosidase production by Lactobacillus acidophilus in a stirred-tank bioreactor. Process parameters (aeration and agitation) were optimized for the process by application of Central Composite Design. Aeration rate of 0.5 vvm and agitation speed of 250 rpm were most suitable for β-galactosidase production (2001.2 U/L). Further improvement of the operation in pH controlled environment resulted in 2135 U/L of β-galactosidase with productivity of 142.39 U/L h. Kinetic modeling for biomass and enzyme production and substrate utilization were carried out at the aforementioned pH controlled conditions. The logistic regression model (X0 = 0.01 g/L; Xmax = 2.948 g/L; μmax = 0.59/h; R2 = 0.97) was used for mathematical interpretation of biomass production. Mercier's model proved to be better than Luedeking–Piret model in describing β-galactosidase production (P0 = 0.7942 U/L; Pmax = 2169.3 U/L; Pr = 0.696/h; R2 = 0.99) whereas the latter was more efficient in mathematical illustration of lactose utilization (m = 0.187 g/g h; Yx/s = 0.301 g/L; R2 = 0.98) among the two used in this study. Strategies like fed-batch fermentation (3694.6 U/L) and semi-continuous fermentation (5551.9 U/L) further enhanced β-galactosidase production by 1.8 and 2.8 fold respectively.  相似文献   

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