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991.
The production of polyhydroxyalkanoates(PHA) from wastewaters using microbial mixed cultures(MMC) has been attracting increased interest because of PHA's biodegradability characteristics. Production of PHA by an MMC enriched with PHA-accumulating bacteria was compared using anaerobically treated and acidified brewery wastewaters under various feeding strategies, namely pulse and batch feed addition. To obtain an enriched MMC, a sequencing batch reactor was inoculated with activated sludge fed with acetate and subjected to aerobic dynamic feeding. The enriched MMC was able to accumulate PHA up to 72.6% of cell dry weight(CDW) with pulse addition of acetate controlled by the dissolved oxygen(DO) concentration in the reactor. In a batch accumulation experiment with acetate,the PHA content achieved(28.5% CDW) was less than that of the pulse feeding strategy with the same amount of acetate(~2000 mg C/L). Using anaerobically treated and acidified brewery wastewater fed in pulses, the maximum PHA accumulated by the enriched MMC was similar for both wastewaters(45% CDW), in spite of the higher volatile fatty acid concentration in acidified brewery wastewater. The pulse feed addition controlled by the DO concentration was difficult to implement for wastewater as compared to acetate because the difference in DO concentration between substrate availability and depletion was low. For the batch addition of acidified wastewater, a slightly lower PHA content(39%CDW) was obtained. These results show that both brewery wastewaters can be utilized for PHA production with a similar maximum PHA storage capacity.  相似文献   
992.
Fungus-induced galls can attract spore-feeding arthropods as well as gall-feeding ones, resulting in diverse communities. Do large fungal galls support more abundant and diverse arthropod communities than small fungal galls? To address this question, we investigated the structure of the arthropod community associated with bud galls induced by the fungus Melanopsichium onumae on the tree species Cinnamomum yabunikkei (Lauraceae) in central Japan. Thirteen species of arthropods were associated with M. onumae galls. Dominant arthropod species were represented by the larvae of a salpingid beetle (a spore feeder), a nitidulid beetle (a spore feeder), a cosmopterigid moth (a spore feeder), an unidentified moth (a gall tissue feeder), and a drosophilid species (a gall tissue feeder). Arthropod abundance and species richness were positively correlated with gall diameter. The majority of the most abundant species were more frequently found in large galls than in small ones, indicating that large fungal galls, which have more food and/or space for arthropods, could support a more abundant and diverse arthropod community.  相似文献   
993.
Fossilized soft tissues, occasionally found together with skeletal remains, provide insights to the physiology and functional morphology of extinct organisms. Herein, we present unusual fossilized structures from the cortical region of bone identified in isolated skeletal remains of Middle Triassic nothosaurs from Upper Silesia, Poland. The ribbed or annuli-shaped structures have been found in a sample of partially demineralized coracoid and are interpreted as either giant red blood cells or as blood vessel walls. The most probable function is reinforcing the blood vessels from changes of nitrogen pressure in air-breathing diving reptiles. These structures seem to have been built of extensible muscle layers which prevent the vessel damage during rapid ascent. Such suspected function presented here is parsimonious with results of previous studies, which indicate rarity of the pathological modification of bones associated with decompression syndrome in Middle Triassic nothosaurs.  相似文献   
994.
We investigate chemical aspects of mating in the marine copepod Temora longicornis (Copepoda, Calanoidea). Our emphasis is the female pheromone signaling in form of well-defined trails for males to follow, observed in Doall et al. (Phil Trans R Soc Lond B 353:681–689, 1998). The viscous environment and the properties of the odorants play important roles as the spread of the pheromone trail limits the time during which it is useful for tracing. A key observation from our earlier work is the ability of a searching male to detect the direction of the female and to correct its swimming direction if necessary. We propose a simple mathematical model for the spread of a pheromone from a moving source and carry out numerical simulations of two possible detection mechanisms. We find that a searching agent that is capable to detect a ratio outperforms a searcher that depends on the gradient of a single compound. This suggests that copepod sex pheromones consist of blends of chemical compounds, and that a ratio detection mechanism similar to that in airborne insects is at work.  相似文献   
995.
Despite the (TTAGG)n telomeric repeat supposed being the ancestral DNA motif of telomeres in insects, it was repeatedly lost within some insect orders. Notably, parasitoid hymenopterans and the social wasp Metapolybia decorata (Gribodo) lack the (TTAGG)n sequence, but in other representatives of Hymenoptera, this motif was noticed, such as different ant species and the honeybee. These findings raise the question of whether the insect telomeric repeat is or not phylogenetically predominant in Hymenoptera. Thus, we evaluated the occurrence of both the (TTAGG)n sequence and the vertebrate telomere sequence (TTAGGG)n using dot-blotting hybridization in 25 aculeate species of Hymenoptera. Our results revealed the absence of (TTAGG)n sequence in all tested species, elevating the number of hymenopteran families lacking this telomeric sequence to 13 out of the 15 tested families so far. The (TTAGGG)n was not observed in any tested species. Based on our data and compiled information, we suggest that the (TTAGG)n sequence was putatively lost in the ancestor of Apocrita with at least two subsequent independent regains (in Formicidae and Apidae).  相似文献   
996.
The aim of this study was to assess the trend of hepatitis A virus (HAV) in a coastal zone impacted by a contamination event, providing data for the development of management strategies. A total of 352 samples, including four bivalve mollusc species (Mytilus galloprovincialis, Solen vagina, Venus gallina and Donax trunculus), were taken over a period of 6 months from 27 production areas of the coast and analysis were performed according to ISO/TS 15216-1:2013. HAV presence was detected in 77 samples from 11 production areas and all positive results were related to samples collected in the first 3 months of the surveillance, during which HAV prevalence was 39.9% and values as high as 5096 genome copies/g were detected. A progressive reduction of viral contamination was evident during the first trimester of the monitoring, with prevalence decreasing from 78.8% in the first month, to 37.8% in the second and 3.9% in the third and quantitative levels reduced from an average value of 672 genome copies/g to 255 genome copies/g over a period of 4 weeks (virus half-life: 21.5 days). A regression analysis showed that, during the decreasing phase of the contamination, the data fitted a reciprocal quadratic model (Ra2 = 0.921) and, based on the model, a residual presence of HAV could be estimated after negativization of the production areas. The statistical analysis of the results per shellfish species and per production area showed that there were limited differences in contamination prevalence and levels among diverse bivalve species, while a statistically significant difference was present in quantitative levels of one production area. These data could be useful for the development of both risk assessment models and code of practice for the management of viral contamination in primary production.  相似文献   
997.
The improvement of safety in the process industries is related to assessment and reduction of risk in a cost-effective manner. This paper addresses the trade-off between risk and cost related to standby safety systems. An age-dependent unavailability model that integrates the effects of the test and maintenance (T&M) activities as well as component ageing is developed and represents the basis for calculating risk. The repair “same-as-new” process is considered regarding the T&M activities. Costs are expressed as a function of the selected risk measure. The time-averaged function of the selected risk measure is obtained from probabilistic safety assessment, i.e. the fault tree analysis. This function is further extended with inclusion of additional parameters related to T&M activities as well as ageing parameters related to component ageing. In that sense, a new model of system unavailability, incorporating component ageing and T&M costs, is presented. The testing strategy is also addressed. Sequential and staggered testings are compared. The developed approach is applied on a standard safety system in nuclear power plant although the method is applicable to standby safety systems that are tested and maintained in other industries as well. The results show that the risk-informed surveillance requirements differ from existing ones in technical specifications, which are deterministically based. Moreover, the presented approach achieves a significant reduction in system unavailability over a relatively small increase of total T&M costs.  相似文献   
998.
Since the late 1980s, our group has examined the effects of radiofrequency electromagnetic fields (RF-EMF), including pulse-modulated waves of the type emitted by mobile phones, upon the blood?Cbrain barrier. In more than 2,000 rats, we have repeatedly demonstrated a passage of the rats?? own albumin from the blood through the brain capillaries into the surrounding brain parenchyma at SAR values down to 0.1mW/kg. In most of these experiments, the animals were exposed in TEM-cells, ventilated by an external electrical fan at 50 Hz. In the present study, we examined whether the extremely low frequency (ELF) magnetic fields from the fan (50 Hz, 0.3?C1.5 ??T) might add to the RF effect. Sixty-four rats were divided into 4 groups: RF only, ELF only and RF + ELF exposure plus a sham group. The GSM-900 MHz RF exposure was at the very low, nonthermal, average whole-body SAR level 0.4 mW/kg. Demonstration of the normally occurring albumin extravasation in the basal hypothalamus is our inbuilt control proving that the staining is reliable. Two full series of staining of the whole material gave negative results for hypothalamus. Not until we changed to avidin, biotin, and antibodies from a third supplier, we received an acceptable staining. Twenty-five percent of the RF animals had a pathological albumin leakage, while the ELF and RF + ELF groups with three and two pathological findings, respectively, were not significantly different from the control group. We conclude that the use of external fans has had no major influence upon the result.  相似文献   
999.
In spite of widespread support from most member countries’ societies for European Union policy, including support for the sustainable development idea, in many EU countries the levels of acceptance of new environmental protection programmes have been and, in particular in new member states, still are considerably low. The experience of the countries which were the first to implement union directives show that they cannot be effectively applied without widespread public participation. The goal of this study was, using the example of Poland, to assess public acceptance of the expansion of nature conservation in the context of sustainable development principles and to discover whether existing nature governance should be modified when establishing new protected areas. The increase in protected areas in Poland has become a hotbed of numerous conflicts. In spite of the generally favourable attitudes to nature which Polish people generally have, Natura 2000 is perceived as an unnecessary additional conservation tool. Both local authorities and communities residing in the Natura areas think that the programme is a hindrance, rather than a help in the economic development of municipalities or regions, as was initially supposed. This lack of acceptance results from many factors, mainly social, historic and economic. The implications of these findings for current approach to the nature governance in Poland are discussed.  相似文献   
1000.
In recent years, altered forest conditions, climate change, and the increasing numbers of homes built in fire prone areas has meant that wildfires are affecting more people. An important part of minimizing the potential negative impacts of wildfire is engaging homeowners in mitigating the fire hazard on their land. It is therefore important to understand what makes homeowners more or less willing to take action. The research presented here comes from a study that interviewed a total of 198 homeowners in six communities in the western United States about the activities they had undertaken to mitigate their fire risk, the factors that contributed to their decisions, and their future intentions. The current paper reports on findings from the first half of the longitudinal study, after 3 years we will return to interview the current homeowner on the same properties to assess maintenance actions and facilitating and limiting factors. Overall we found a body of individuals who understand the fire risk, are taking numerous mitigation actions, and think that these actions have reduced their risk. These homeowners typically did not expect the government to do it for them: they wanted information about what to do and, in some cases, assistance with the work, but saw taking care of their property primarily as their responsibility. Responses also show that key information sources and motivating factors vary by location and that it is not inherently necessary to have relationships between community members to create defensible space.  相似文献   
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