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1.
This study investigated if atmospheric ammonia (NH3) pollution around a sheep farm influences the photosynthetic performance of the lichens Evernia prunastri and Pseudevernia furfuracea. Thalli of both species were transplanted for up to 30 days in a semi-arid region (Crete, Greece), at sites with concentrations of atmospheric ammonia of ca. 60 μg/m3 (at a sheep farm), ca. 15 μg/m3 (60 m from the sheep farm) and ca. 2 μg/m3 (a remote area 5 km away). Lichen photosynthesis was analysed by the chlorophyll a fluorescence emission to identify targets of ammonia pollution. The results indicated that the photosystem II of the two lichens exposed to NH3 is susceptible to this pollutant in the gas-phase. The parameter PIABS, a global index of photosynthetic performance that combines in a single expression the three functional steps of the photosynthetic activity (light absorption, excitation energy trapping, and conversion of excitation energy to electron transport) was much more sensitive to NH3 than the FV/FM ratio, one of the most commonly used stress indicators.  相似文献   
2.
In this study, a biomonitoring project using the moss Scorpiurum circinatum was carried out to evaluate the deposition and biological effects of heavy metals in the area of Acerra (Naples, S Italy), one of the vertices of the sadly called “Italian triangle of death” owing to the dramatic increase in tumours. The results clearly indicated that the study area is heavily polluted by heavy metals, a large proportion of which is likely present in the atmosphere in particulate form. The ultrastructural organization of exposed samples was essentially preserved, but cell membrane pits, cytoplasm vesicles and concentric multilamellar/multivesicular bodies, probably induced by pollution, were found, which may be involved in the tolerance mechanisms to metal pollution in this moss species. Although severe biological effects were not found at the ultrastructural level in the exposed moss, effects on humans, especially after long-term exposure, are to be expected.  相似文献   
3.
The analysis of habitat selection in radio-tagged animals is approached by comparing the portions of use against the portions of availability observed for each habitat type. Since data are linearly dependent with singular variance-covariance matrices, standard multivariate statistical tests cannot be applied. To bypass the problem, compositional data analysis is customarily performed via log-ratio transform of sample observations. The procedure is criticized in this paper, emphasizing the several drawbacks which may arise from the use of compositional analysis. An alternative nonparametric solution is proposed in the framework of multiple testing. The habitat use is assessed separately for each habitat type by means of the sign test performed on the original observations. The resulting p values are combined in an overall test statistic whose significance is determined permuting sample observations. The theoretical findings of the paper are checked by simulation studies. Applications to case studies previously considered in literature are discussed.  相似文献   
4.
Public healthcare wastes from the region of Ribeirão Preto, Brazil, pre-sterilized in an autoclave, were inoculated with spores of Bacillus atrophaeus for microwave processing on a laboratory scale. The influence of waste moisture (40%, 50% and 60% wet basis), presence of surfactant, power per unit mass of waste (100, 150 and 200 W/kg) and radiation exposure time (from 5 to 40 min) on the heating curves was investigated. The most favorable conditions for waste heating with respect to moisture and use of surfactant were then applied in an experimental analysis of the degree of inactivation of B. atrophaeus spores as a function of time and power per unit mass of waste. Based on Chick’s and Arrhenius laws, the experimental results were adjusted by the least squares method to determine the activation energies (9203–5782 J/mol) and the Arrhenius pre-exponential factor (0.23 min?1). The kinetic parameters thus obtained enabled us to predict the degree of inactivation achieved for B. atrophaeus spores in typical healthcare waste. The activation energy was found to decrease as the power per waste mass increased, leading to the conclusion that, in addition to the thermal effect on the inactivation of B. atrophaeus spores, there was an effect inherent to radiation.  相似文献   
5.
Environmental and Ecological Statistics - In the inverse distance weighting interpolation the interpolated, value is a weighted mean of the sampled values, with weights decreasing with the...  相似文献   
6.
A design-based strategy for estimating wildlife ungulate abundance in a Mediterranean protected area (Maremma Regional Park) is considered. The estimation is based on pellet group count (clearance count technique) in a set of plots, whose size and number is established on the basis of practical considerations and available resources. The sampling scheme involves a preliminary stratification and subsequent two-stage sampling. In the first stage, large strata (defined through habitat features) are partitioned into spatial units and a sample of units is selected by means of a sampling scheme ensuring inclusion probabilities proportional to unit size, but avoiding the selection of contiguous units. Then, the abundances of the selected units are estimated in a second stage, in which plots are located using a random scheme ensuring an even coverage of the units. In small strata, only the second stage is performed. Unbiased estimators of abundance and conservative estimators of their variances are derived for each strata and for the whole study area. The proposed strategy has been applied since the Summer of 2006 and the estimation results reveal substantial improvement with respect to the previous results obtained by means of an alternative strategy.  相似文献   
7.
Drawing upon institutional and stakeholder theories, we explore the ‘causal’ mechanisms of institutionalization and their influence on Sustainable Development initiatives. To test our arguments, we study the registration patterns of 394 large corporations from 12 Western European and Latin American countries into the United Nations Global Compact. Results indicate that the normative and mimetic mechanisms of institutionalization (i.e., academe and peer influence) are better indicators of Sustainable Development initiatives than the coercive one (i.e., government regulation). The implications of these findings are consequential if SD practices continue as an ethical choice, and not a mandated obligation, for corporate decision makers.  相似文献   
8.
The statistical properties of two-stage plot sampling estimators of abundance are considered. In the first stage, some spatial units are selected over the whole study area according to a suitable sampling design, while in the second stage, the selected units are surveyed with floating plot sampling to estimate the abundance within. Some insights into the accuracy of the resulting estimators are obtained by splitting the sample variance into the first and second-stage components, while performance is empirically checked by means of a simulation study. Simulation results show that, in most situations, a relevant amount of the overall variance is due to the second stage sampling.  相似文献   
9.
Public healthcare wastes from the city of Ribeirão Preto, SP, Brazil, pre-sterilised in an autoclave, were inoculated with 5 × 105 microorganisms of the species Escherichia coli in vegetative form for microwave processing on a laboratory scale. An analysis was made of the influence of radiation exposure time (15, 25, 30 and 40 min) and power per waste mass unit (60, 80 and 100 W/kg) on the percentage of inactivation of the microorganisms at an incoming waste moisture level of 50%. The experimental results were adjusted based on Chick’s law. The activation energies and the Arrhenius pre-exponential factors were determined by the least squares method. The kinetic parameters obtained allow one to predict the degree of inactivation achieved with E. coli in typical healthcare waste, based on the radiation exposure time and temperature. For example, the waste disinfection time required for the inactivation level equivalent to 4Log10 was estimated to range from 48 to 53 min for wastes processed at 100 W/kg and at temperatures of 90–105 °C, respectively. Thus, under the operational conditions of the equipment currently used in Ribeirão Preto, the process of inactivation is probably ineffective, since the exposure time to radiation is only 30 min at the average power of approximately 80 W/kg.  相似文献   
10.
Researchers and policymakers emphasize that people’s involvement in forest management can secure their support of conservation initiatives. However, the evidence on the effectiveness of top-down participation is weak. This study uses cross-sectional household data from 16 villages in the buffer zone of Pench Tiger Reserve (Madhya Pradesh) in India to contribute to the evidence base of such assumption. Using a propensity score matching to control for observable bias, we evaluate the effects of two state-driven incentive-based participatory projects, i.e. the Joint Forest Management and Ecodevelopment, on selected social outcomes. Specifically, we measured local people conservation knowledge, biodiversity attitudes as well as trust in and satisfaction with the tiger reserve management authorities. We found that the effects of participatory management on conservation knowledge were positive, but negligible. We found no significant effects on local people’s biodiversity attitudes, trust and satisfaction with the tiger reserve management authorities. Top-down and externally induced participation may explain our results. Our findings clearly indicate that the effectiveness of participatory conservation interventions is conditional on the level and nature of local participation. Top-down participatory projects may not be sufficient to generate local support of conservation and in some cases, they may even exacerbate local conflicts.  相似文献   
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