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21.
Product lifetime is an essential aspect of dynamic material flow analyses and has been modeled using lifetime distribution functions, mostly average lifetimes. Existing data regarding the lifetime of electronic equipment (EE) are based on diverging definitions of lifetime as well as different temporal and regional scopes. After its active use, EE is often not disposed of immediately, but remains in storage for some time. Specific data on the share of EE that is stored and the time they remain in storage are scarce. This article investigates the service lifetime, storage time, and disposal pathways of ten electronic device types, based on data from an online survey complemented by structured interviews. We distinguish between new and secondhand devices and compute histograms, averages, and medians of the different lifetimes and their change over time. The average service lifetime varies from 3.3 years for mobile phones to 10.8 years for large loudspeakers, the average storage time from 0.8 years for flat panel display televisions to 3.6 years for large loudspeakers. Most service lifetime histograms are positively skewed and show substantial differences among device types. The storage time histograms, being more similar to one another, indicate that the storage behavior is similar for most device types. The data on disposal pathways show that a large proportion of devices are stored and reused before they reach the collection scheme.  相似文献   
22.
The hemodynamic response to maximal exercise was determined in rats that were subjected to high-intensity sprint training (HIST) and rats that served as sedentary controls. Training consisted of five 1-min bouts of treadmill running at work loads (15% grade, 97 m/min) in excess of the animals' maximal O2 uptake (VO2max) interspersed with 90 s of rest. Training was performed 6 days/wk for 6 wk. After the training regimen, all rats were acutely instrumented with catheters in the right carotid artery and right ventricle. O2 uptakes, hemodynamic parameters, arterial and mixed venous O2 concentrations, blood gases, and acid-base status were determined at rest and during submaximal and maximal exercise. Results demonstrated that VO2max of HIST rats was significantly greater than that found for sedentary control rats. This increase in VO2max was due to an increase in maximal cardiac output (Qmax), since maximal arteriovenous O2 difference was similar between trained and sedentary rats. The increase in Qmax was due to an increase in maximal stroke volume (SVmax), because maximal heart rate in trained rats was similar to that in sedentary control rats. Citrate synthase and phosphofructokinase activities measured in the white gastrocnemius, plantaris, and soleus muscles of trained and sedentary rats were similar. These results suggest that the increase in VO2max produced with HIST in rats is strongly linked to an increase in central cardiac function as indicated by an increase in Qmax and SVmax.  相似文献   
23.
Electronic textiles are a vanguard of an emerging generation of smart products. They consist of small electronic devices that are seamlessly embedded into clothing and technical textiles. E‐textiles provide enhanced functions in a variety of unobtrusive and convenient ways. Like many high‐tech products, e‐textiles may evolve to become a mass market in the future. In this case, large amounts of difficult‐to‐recycle products will be discarded. That can result in new waste problems. This article examines the possible end‐of‐life implications of textile‐integrated electronic waste. As a basis for assessment, the innovation trends of e‐textiles are reviewed, and an overview of their material composition is provided. Next, scenarios are developed to estimate the magnitude of future e‐textile waste streams. On that base, established disposal and recycling routes for e‐waste and old textiles are assessed in regard to their capabilities to process a blended feedstock of electronic and textile materials. The results suggest that recycling old e‐textiles will be difficult because valuable materials are dispersed in large amounts of heterogeneous textile waste. Moreover, the electronic components can act as contaminants in the recycling of textile materials. We recommend scrutinizing the innovation trend of technological convergence from the life cycle perspective. Technology developers and product designers should implement waste preventative measures at the early phases in the development process of the emerging technology.  相似文献   
24.
The International Journal of Life Cycle Assessment - Improving the quality and quantity of unit process datasets in Life Cycle Inventory (LCI) databases affects every LCA they are used in. However,...  相似文献   
25.
COVID-19 displays diverse disease severities and symptoms including acute systemic inflammation and hypercytokinemia, with subsequent dysregulation of immune cells. Bacterial superinfections in COVID-19 can further complicate the disease course and are associated with increased mortality. However, there is limited understanding of how SARS-CoV-2 pathogenesis and hypercytokinemia impede the innate immune function against bacterial superinfections. We assessed the influence of COVID-19 plasma hypercytokinemia on the functional responses of myeloid immune cells upon bacterial challenges from acute-phase COVID-19 patients and their corresponding recovery-phase. We show that a severe hypercytokinemia status in COVID-19 patients correlates with the development of bacterial superinfections. Neutrophils and monocytes derived from COVID-19 patients in their acute-phase showed an impaired intracellular microbicidal capacity upon bacterial challenges. The impaired microbicidal capacity was reflected by abrogated MPO and reduced NETs production in neutrophils along with reduced ROS production in both neutrophils and monocytes. Moreover, we observed a distinct pattern of cell surface receptor expression on both neutrophils and monocytes, in line with suppressed autocrine and paracrine cytokine signaling. This phenotype was characterized by a high expression of CD66b, CXCR4 and low expression of CXCR1, CXCR2 and CD15 in neutrophils and low expression of HLA-DR, CD86 and high expression of CD163 and CD11b in monocytes. Furthermore, the impaired antibacterial effector function was mediated by synergistic effect of the cytokines TNF-α, IFN-γ and IL-4. COVID-19 patients receiving dexamethasone showed a significant reduction of overall inflammatory markers in the plasma as well as exhibited an enhanced immune response towards bacterial challenge ex vivo. Finally, broad anti-inflammatory treatment was associated with a reduction in CRP, IL-6 levels as well as length of ICU stay and ventilation-days in critically ill COVID-19 patients. Our data provides insights into the transient functional dysregulation of myeloid immune cells against subsequent bacterial infections in COVID-19 patients and describe a beneficial role for the use of dexamethasone in these patients.  相似文献   
26.
Intensive land use can fragment continuous natural areas into smaller patches, which may be too small to support viable populations of native fauna and more susceptible to invasion by alien species. We demonstrate the utility of combining species occurrence models with land-use change models to identify areas where future development may differentially affect wildlife. Occurrence data for native (e.g., gray fox, coyote, bobcat, mountain lion, striped skunk, raccoon) and non-native (e.g., domestic dogs, domestic cats, opossums) mammalian predators were collected from 188 remotely triggered camera locations across an oak woodland and vineyard landscape in northern California. The occurrence data were used in combination with landscape variables extracted using a geographic information system to build explanatory models of predator occurrence. These statistical models were used to derive two surfaces showing relative probability of occurrence for non-native and native predators. Then, a spatially explicit land-use change model was used to examine potential future predator distributions given potential future vineyard expansion. The probability distribution models generated hypothesized low probabilities of occurrence for native predators within large vineyard blocks, but higher probabilities within isolated vineyards and also in oak woodlands. The models suggest the highest probabilities of non-native predator occurrence fell within large blocks of vineyard. Using one possible future vineyard development scenario, the distribution models illustrate areas where probability of native predator occurrence may be reduced and where non-native predators may expand due to vineyard development. This technique could be applied to prioritize acquisition of critical wildlife habitat and maintain habitat connectivity for wildlife populations.  相似文献   
27.
28.
Goal, Scope and Background Telephony as well as remote data transfer is increasingly performed via mobile phone networks. However, the environmental consequences, in particular of the End-of-Life (EOL) treatment, of such network infrastructures have been investigated insufficiently to date. In the present report the environmental implications of the EOL treatment of a single GSM 900 antenna rack have been analysed. Methods Based on comprehensive inventories of a GSM 900 antenna station rack and currently applied EOL treatment, the environmental impacts related to the EOL treatment of the rack are investigated. Six different EOL treatment scenarios are developed to find an environmentally safe treatment alternative. System expansion, i.e. inclusion of the production phase, is applied to all scenarios in order to consider different amounts of regained materials. Results and Discussion The production of primary rack materials, especially that of palladium (accounts for almost 40% of the ecotoxicity impact category), to substitute lost materials dominates the overall environmental impact. Releases of heavy metals from landfilled rack components / materials and of by-products to the environment greatly influence the overall impacts on human health and ecosystem quality. The final disposal of rack components contributes to about 70% of the non-carcinogenic effects. Landfilled dust from steel production contributes to nearly 11% of this impact category. Conclusion The results suggest that all precious metals containing electronic scrap should be treated in specially equipped metal recovery plants. A complete rack disassembly before processing in high-standard metal recovery plants is not necessary. An elaborated pre-treatment and fractionation of the scrap prior to precious material recovery does not lower the environmental impacts and is not mandatory and would only become environmentally interesting if high recovery of heavy metals is achieved. To avoid the formation and release of volatile and toxic heavy metal, incineration of electronic scrap as of by-products prior to landfilling should be avoided. To reduce the overall environmental load, a standardisation of the sizes of rack components, facilitating their re-use, is recommended.  相似文献   
29.
Large tracts of natural habitat are being replaced by agriculture and urban sprawl in Mediterranean regions worldwide. We have limited knowledge about the effects of human activities on native species in these landscapes and which, if any, management practices might enhance the conservation of native biodiversity within them. Through a citizen volunteer bird-monitoring project, we compared bird abundance and species richness in northern Californian riparian zones surrounded by vineyards, urban areas, and natural areas. We assessed both local and landscape-level variables that may enhance native bird diversity in each land use type. We also demonstrate a new statistical approach, generalized estimating equations, to analyze highly variable data, such as that collected by volunteers. Avian abundance was highly correlated with both landscape context and local habitat variables, while avian richness was correlated with local habitat variables, specifically shrub richness, and percent of tree cover. In particular, shrub species richness has a strong positive correlation with riparian-preferring bird species. This suggests that active local management of riparian zones in human-dominated landscapes can increase our ability to retain native bird species in these areas.  相似文献   
30.
Objective To examine the financial and organizational characteristics, demand for services, and satisfaction outcomes of a growing telemedicine program serving both urban or suburban and rural populations. Design Retrospective review of 1,000 consecutive telemedicine consultations in the University of California (UC) Davis Telemedicine Program. Setting Telemedicine videoconferencing units, used to integrate care in the UC Davis Health System among the UC Davis Medical Center and several urban or suburban primary care clinics, rural hospitals, and clinic affiliates. Subjects A total of 657 consecutive patients who consented to a telemedicine consultation. Main outcome measures Demographic information about the patient population, the rural and urban or suburban clinics, the types of specialty consultations, and telemedicine equipment used in the UC Davis Health System. Patient and physician satisfaction were measured on a 5-point Likert scale. Results Patients and primary care physicians reported high levels of satisfaction. Rural clinics requested more and a greater variety of specialist consultations than urban or suburban clinics. Conclusion Although referring physicians and patients indicate a high level of satisfaction with telemedicine services and insurers are negotiating reimbursement policies, additional research must investigate the reasons why some payers, patients, and providers resist participation in these services.  相似文献   
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