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901.
Biomass is an important entity to understand the capacity of an ecosystem to sequester and accumulate carbon over time. The present study, done in collaboration with the Delhi Forest Department, focused on the estimation of growing stock and the woody biomass in the so-called lungs of Delhi—the Asola-Bhatti Wildlife Sanctuary in northern Aravalli hills. The satellite-derived vegetation strata were field-inventoried using stratified random sampling procedure. Growing stock was calculated for the individual sample plots using field data and species-specific volume equations. Biomass was estimated from the growing stock and the specific gravity of the wood. Among the four vegetation types, viz. Prosopis juliflora, Anogeissus pendula, forest plantation and the scrub, the P. juliflora was found to be the dominant vegetation in the area, covering 23.43 km2 of the total area. The study revealed that P. juliflora forest with moderate density had the highest (10.7 m3/ha) while A. pendula forest with moderate density had the lowest (3.6 m3/ha) mean volume. The mean woody biomass was also found to be maximum in P. juliflora forest with moderate density (10.3 t/ha) and lowest in A. pendula forest with moderate density (3.48 t/ha). The total growing stock was estimated to be 20,772.95 m3 while total biomass worked out to be 19,366.83 t. A strong correlation was noticed between the normalized difference vegetation index (NDVI) and the growing stock (R 2?=?0.84)/biomass (R 2?=?0.88). The study demonstrated that growing stock and the biomass of the woody vegetation in Asola-Bhatti Wildlife Sanctuary could be estimated with high accuracy using optical remote sensing data.  相似文献   
902.
This paper addresses the phenotypic variation among Ricinus communis L. populations in four urban habitat types (road verges, garbage dumps, construction debris, and natural area) in Delhi, India, by evaluating important traits such as plant height, basal circumference, seeds per plant, seed size, seed weight, specific leaf area, and reproductive index. An important biochemical marker, proline, considered as a good plant performance indicator under stress was also quantified in leaves of R. communis to evaluate its response in different habitats. Interestingly, the species showed significant variation in plant height, specific leaf area, seed size, seed weight, and leaf proline content in different habitat types. Leaf proline content was positively related to plant height, specific leaf area, and seed size while negatively related to the total number of seeds/plant. Interestingly, reproductive index, calculated as a ratio of the total number of seeds to the plant height also showed a negative relation with leaf proline content. Results indicated that R. communis exhibits adaptive modulation of growth, reproductive traits, and leaf proline content in various urban habitats which contributes to invasiveness, range expansion, and establishment of the species. The study also gives evidence of how morphological and physiological traits could directly affect invasiveness of R. communis.  相似文献   
903.
Good lighting and the correct use of spectacles generally improve vision and presumably reduce the risk of accidents. However, bifocal and varifocal spectacles can increase the risk of misjudging distances when negotiating underfoot hazards. In some circumstances, the portion of the lens used for close work may inadvertently be used where accurate judgement of distance is necessary. This paper reports results from two studies of patient interviews using the Merseyside Accident Information Model; the first a study of accidents which occurred during paid employment (1504 cases) and the second of 1326 accidents mainly in domestic and leisure activities. Underfoot accidents were identified by the first unforeseen event perceived by the patient. The relationship between underfoot events and the type of spectacles worn by the patient at the time of accident was analysed. In both studies there was a significant association between accidents where the first event was ‘missed edge of’ (step) and wearing bifocal/varifocal spectacles. Corporal movements reported in both studies indicated that ‘stepping down’ when wearing bifocal/varifocal spectacles, increased the risk of ‘missed edge’ accidents. In the work environment corporal movements associated with manual handling of loads also increased the risk of ‘missed edge’ accidents when wearing bifocal/varifocal spectacles.  相似文献   
904.
The purpose of this review was to summarize the literature on occupational, acute, traumatic hand injury and suggest directions for future research. In 1996, the leading occupational injury treated in United States' hospital emergency departments was an acute hand injury (e.g. laceration, crush or fracture). These injuries affected 30% of an estimated 3.3 million injured workers (990,000). Cuts and lacerations of the fingers ranked third after back and leg strains in the number of lost workday cases in the USA in 1994. The incidence rate of hand injuries studied in seven manufacturing environments around the world ranged from 4 to 11 per 100 workers per year. Workers aged 24 years or less had the highest risk of hand injury. Men had higher rates of severe hand injury than women.Despite the high frequency and significant amount of lost work time associated with these injuries, they are poorly understood from an etiological perspective. There is only one case-control study of occupational hand injury in the literature. That study suggested an important role for both fixed (age) and transient risk factors (doing an unusual task) at the time of the injury. More analytic epidemiological research is needed to identify potentially modifiable risk or protective factors (e.g. glove use) for acute hand injuries. In this regard, the case-crossover design, a relatively new epidemiological approach using cases as their own controls, could prove an efficient method for determining transient, modifiable risk factors for acute, occupational hand injury.  相似文献   
905.
Feedback from 360 degree ratings based on competency principles and used for developmental purposes was investigated for interrelationships among the ratings and for its relationships with performance and selection data. Relationships among: (1) feedback ratings from supervisors, peers, and self; (2) feedback ratings and selection test data; and (3) feedback ratings and performance appraisals on about 2000 employees of a Midwestern insurance company were examined. The 360 ratings by peers and managers were related to performance appraisals. All significant correlations of manager and peer ratings with selection tests were positive, but significant correlations of 360 degree self‐ratings with selection tests were negative. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
906.
The present study aims to identify the potential habitat for swamp deer (Cervus duvauceli duvauceli Cuvier) in Jhilmil Jheel Conservation Reserve in the Uttarakhand province of India using multi-criteria analysis. The study area represents one of the last remnant habitats of the flagship species, the swamp deer in Uttarakhand, which is considered as vulnerable. The study showed that only 6.08% of the study area (225 km2) was highly suitable to suitable for the swamp deer. An area of 135.52 km2 (60.23%) turned out to be moderately suitable. Within the officially designated Conservation Reserve (area 37.84 km2), 10.91% (4.13 km2) area was found highly suitable to suitable, while 74.19% (28.07 km2) happens to be moderately suitable. Only 14 km2 area, which was found as suitable habitat for swamp deer falls short of the space required by a population of 134 animals. The problem could be mitigated if the agricultural land (2.47 km2) adjacent to the Jhilmil Jheel is brought under the Reserve management. This would provide additional area to meet the fodder requirement. The study brings out a particularly grim situation with limited options for conservation and management of the swamp deer in the Indo-Gangetic plains. It also emphasizes the role of geospatial techniques in quick appraisal of habitat attributes and identification of potential sites for protected areas.  相似文献   
907.
Sediment and phosphorus (P) transport from the Minnesota River Basin to Lake Pepin on the upper Mississippi River has garnered much attention in recent years. However, there is lack of data on the extent of sediment and P contributions from riverbanks vis-à-vis uplands and ravines. Using two light detection and ranging (lidar) data sets taken in 2005 and 2009, a study was undertaken to quantify sediment and associated P losses from riverbanks in Blue Earth County, Minnesota. Volume change in river valleys as a result of bank erosion amounted to 1.71 million m over 4 yr. Volume change closely followed the trend: the Blue Earth River > the Minnesota River at the county's northern edge > the Le Sueur River > the Maple River > the Watonwan River > the Big Cobb River > Perch Creek > Little Cobb River. Using fine sediment content (silt + clay) and bulk density of 37 bank samples representing three parent materials, we estimate bank erosion contributions of 48 to 79% of the measured total suspended solids at the mouth of the Blue Earth and the Le Sueur rivers. Corresponding soluble P and total P contributions ranged from 0.13 to 0.20% and 40 to 49%, respectively. Although tall banks (>3 m high) accounted for 33% of the total length and 63% of the total area, they accounted for 75% of the volume change in river valleys. We conclude that multitemporal lidar data sets are useful in estimating bank erosion and associated P contributions over large scales, and for riverbanks that are not readily accessible for conventional surveying equipment.  相似文献   
908.
Low-disturbance manure application methods can provide the benefits of manure incorporation, including reducing ammonia (NH3) emissions, in production systems where tillage is not possible. However, incorporation can exacerbate nitrate (NO3?) leaching. We sought to assess the trade-offs in NH3 and NO3? losses caused by alternative manure application methods. Dairy slurry (2006-2007) and liquid swine manure (2008-2009) were applied to no-till corn by (i) shallow (<10 cm) disk injection, (ii) surface banding with soil aeration, (iii) broadcasting, and (iv) broadcasting with tillage incorporation. Ammonia emissions were monitored for 72 h after application using ventilated chambers and passive diffusion samplers, and NO3? leaching to 80 cm was monitored with buried column lysimeters. The greatest NH3 emissions occurred with broadcasting (35-63 kg NH3-N ha?), and the lowest emissions were from unamended soil (<1 kg NH-N ha?1). Injection decreased NH-N emissions by 91 to 99% compared with broadcasting and resulted in lower emissions than tillage incorporation 1 h after broadcasting. Ammonia-nitrogen emissions from banding manure with aeration were inconsistent between years, averaging 0 to 71% that of broadcasting. Annual NO3? leaching losses were small (<25 kg NO3-N ha?1) and similar between treatments, except for the first winter when NO3? leaching was fivefold greater with injection. Because NO3? leaching with injection was substantially lower over subsequent seasons, we hypothesize that the elevated losses during the first winter were through preferential flow paths inadvertently created during lysimeter installation. Overall, shallow disk injection yielded the lowest NH3 emissions without consistently increasing NO3? leaching, whereas manure banding with soil aeration conserved inconsistent amounts of N.  相似文献   
909.
A series of miscible-displacement experiments was conducted to examine the retention and transport behavior of oocysts in natural porous media. Three soils and a model sand were used that differed in physical and geochemical properties. Transport behavior was examined under various treatment conditions to help evaluate retention mechanisms. Significant retention of oocysts was observed for all media despite the fact that conditions were unfavorable for physicochemical interactions with respect to DLVO theory. The magnitude of retention was not influenced significantly by alterations in solution chemistry (reduction in ionic strength) or soil surface properties (removal of soil organic matter and metal oxides). On the basis of the observed results, it appears that retention by secondary energy minima or geochemical microdomains was minimal for these systems. The porous media used for the experiments exhibited large magnitudes of surface roughness, and it is suggested that this surface roughness contributed significantly to oocyst retention.  相似文献   
910.
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