建筑产品与生命周期思考

生命周期理念,在与建筑和建设部门的关系中,特别应该进行建筑产品分析、在提高建筑物能源效率并为经济繁荣有所贡献的时候,这些产品发挥着基本的作用,已经做出的要算披露,在从自然索取的物质资源和产生的垃圾总量中,有一半来自建筑部门,为了对建筑产品的影响进行和理并把综降到最低,就必须利用生命周期的方法对所产生的影响进生检测,本文评论了生命周期理念并思考了最新的发展.材料与可持续建筑,环境产品宣言,所体现的能源以及北方与南言建筑产品评估中产生的差异,都是要讨论的话题.     

Predicting tree species presence and basal area in Utah: A comparison of stochastic gradient boosting,generalized additive models,and tree-based methods

Many efforts are underway to produce broad-scale forest attribute maps by modelling forest class and structure variables collected in forest inventories as functions of satellite-based and biophysical information. Typically, variants of classification and regression trees implemented in Rulequest's^© See5 and Cubist (for binary and continuous responses, respectively) are the tools of choice in many of these applications. These tools are widely used in large remote sensing applications, but are not easily interpretable, do not have ties with survey estimation methods, and use proprietary unpublished algorithms. Consequently, three alternative modelling techniques were compared for mapping presence and basal area of 13 species located in the mountain ranges of Utah, USA. The modelling techniques compared included the widely used See5/Cubist, generalized additive models (GAMs), and stochastic gradient boosting (SGB). Model performance was evaluated using independent test data sets. Evaluation criteria for mapping species presence included specificity, sensitivity, Kappa, and area under the curve (AUC). Evaluation criteria for the continuous basal area variables included correlation and relative mean squared error. For predicting species presence (setting thresholds to maximize Kappa), SGB had higher values for the majority of the species for specificity and Kappa, while GAMs had higher values for the majority of the species for sensitivity. In evaluating resultant AUC values, GAM and/or SGB models had significantly better results than the See5 models where significant differences could be detected between models. For nine out of 13 species, basal area prediction results for all modelling techniques were poor (correlations less than 0.5 and relative mean squared errors greater than 0.8), but SGB provided the most stable predictions in these instances. SGB and Cubist performed equally well for modelling basal area for three species with moderate prediction success, while all three modelling tools produced comparably good predictions (correlation of 0.68 and relative mean squared error of 0.56) for one species.     

Schooling mackerel and herring choose neighbours of similar size

Fish schooling in a submerged sea-cage swam next to neighbours of similar size. Between 57 and 74 fish were used. Extensive three-dimensional data showed the neighbour size effect for two different species, herring and mackerel, during both day and night. These experiments, covering sizes which coexist in the wild, are the first demonstration of the neighbour size choice in fish schools predicted by theories of hydrodynamic advantage.     

Adequacy of Wildlife Habitat Relation Models for Estimating Spatial Distributions of Terrestrial Vertebrates

In the U.S. National Biological Service's gap analysis, potential distributions of terrestrial vertebrate species are based on the synthesis of wildlife habitat relation data and then modeled using a vegetation cover map derived from Landsat Thematic Mapper imagery. Using long-term species lists from eight National Parks in Utah, we evaluated the adequacy of the wildlife habitat relations data generated by gap analysis in predicting species distributions at landscape scales. Omission and commission error rates were estimated for major taxonomic groups and for each national park. Depending on the taxonomic group, omission error ranged from 0 to 25%, whereas commission error ranged from 4 to 33%. Error rates were highest in amphibians and reptiles and lowest for birds and mammals. In general, the error rate declined as the size of the park increased. The Utah wildlife habitat relation models performed well when used to predict the presence or absence of terrestrial vertebrates in eight national parks in Utah and should provide valuable information for making conservation decisions. They also provide a measure of support for the use of these models within the gap analysis framework. Although it is likely that accuracy of wildlife habitat relation models will vary from state to state, and even considerably within a state, the modeling process seems robust enough to provide a reasonably high level of accuracy for use in conservation planning at the ecoregion level.     

Osmoacclimation in Enteromorpha intestinalis: long-term effects of osmotic stress on organic solute accumulation

The fate of the protease trypsin in intestines of individual herring larvae Clupea harengus L. was studied following digestion of the copepod Acartia tonsa. Trypsin was retained in the intestine during two consecutive pulses of feeding and defaecation of copepods. Quantification of herring trypsin in digested, defaecated copepods showed that ca. 1% of larval intestinal enzyme was defaecated along with 1 to 3 copepods. Following ingestion of a single meal, the level of intestinal trypsin post-ingestion declined to pre-ingestion levels within 1 to 2 d of starvation. All enzyme data thus indicated that trypsin, released in response to ingestion of a meal, was retained. In addition, analysis of fed subgroups of starved larvae clearly indicated that release of trypsin from the pancreas stopped after 6 to 8 d of starvation. As the fish still contained substantial amounts of trypsinogen, the underlying cause might be defective release mechanisms. Daily secretion of trypsin and processes responsible for enzyme retention in the gut are discussed. Assimilation efficiency in herring larvae was estimated for copepodite prey. Average carbon assimilation was 90%.     

Long-term nutrient enrichment of an estuarine system: Ythan, Scotland (1958-1993)

A comprehensive review is given of past and current annually averaged nutrient concentrations (total oxidised nitrogen [TON], phosphate and silicate) in the River Ythan and its estuary. TON concentrations in the River Ythan have increased from ca 100-150 microm in the late 1960s to ca 500-550 microm in the early 1990s, changes which are also shown in the estuary. The interpretation of the phosphate data is more complex but concentrations in the estuary also appear to have increased. Silicate concentrations have remained constant with time. The results of 11 surveys of the estuary completed during 1993 are given. TON and silicate behave conservatively in the estuary, with concentrations determined by those of the fresh water end-member and hence by processes within the catchment. Phosphate and ammonia concentrations at low salinity are affected by the discharge from the Ellon sewage treatment facility at the head of the estuary. Throughout the estuary there is evidence of an input of ammonia to the water column from the sediments, but it represents only ca 0.2-2% of the nitrogen entering from the River Ythan. Despite the increased nutrient loading to the estuary there is no evidence that this has resulted in higher chlorophyll concentrations in the water column, this observation is attributed to the relatively short flushing period of the estuary.     

Sampling Considerations for Establishment of Baseline Loadings from Forested Watersheds for TMDL Application

Five methods for estimating maximum daily and annual nitrate (NO3) and suspended sediment loads using periodic sampling of varying intensities were compared to actual loads calculated from intensive stormflow and baseflow sampling from small, forested watersheds in north central West Virginia to determine if the less intensive sampling methods were accurate and could be utilized in TMDL development. There were no significant differences between the annual NO3 load estimates using non-intensive sampling methods and the actual NO3 loads. However, maximum daily NO3 loads were estimated less accurately than annual loads. The ability to estimate baseline NO3 loads fairly accurately with non-intensive concentration data is attributed to the small fluctuation in NO3 concentrations over flow and time, particularly during storms. By contrast, suspended sediment exports determined by any of the non-intensive methods varied significantly and widely from and compared poorly to the actual exports for both daily and annual methods. Weekly sampling better approximated actual annual exports, but there were no significant statistical differences among weekly, monthly, and quarterly estimates. Suspended sediment concentrations varied widely within and among storm events, so that accurate estimates of total annual or maximum daily loads could not be obtained from infrequent sampling.     

Ozone Exposures and Implications for Vegetation in Rural Areas of the Central Appalachian Mountains, U.S.A.

The United States is making the transition from the 1979 1 hr maximum ozone standard to the newly adopted 8 hr ozone standard (3 yr average of the 4th highest maximum 8 hr ozone concentration). Consequently, we analyzed and compared ozone concentrations under both standards from a variety of monitoring sites throughout the central Appalachian region of Kentucky (KY), West Virginia (WV), and Virginia (VA). Data from 1988-1999 were used to determine how ozone exposure between the two metrics compared for remote sites. Most sites exceeded the 1 hr standard in 1988-1990 due to the 3 yr averaging and multiple high ozone concentrations that occurred over the region in 1988. All sites were in compliance with the 1 hr standard every year after 1991. It was much more common for the ozone exposure to exceed the 8 hr standard, particularly from 1997-1999. Many sites showed exceedences beginning in 1995; Big Meadows (VA) exceeded the 8 hr standard all years except 1994 and 1996. Response of vegetation to ozone in these areas was determined using the combination of W126 values (sigmoidally weighted exposure index), the number of hours that average concentrations > or = 0.10 ppm (N100), and the presence of moderate or more extreme droughts. In general, W126 and N100 values suggested that negative vegetation growth responses over most of the 12 yr would have been minimal for most sites, even for those exceeding ozone standards. Drought-induced stomatal closures would have overridden more extreme negative growth responses at all but the Big Meadows site in 1988.     

Measurements of nitrogen oxides from Hudson Bay: Implications for NOx release from snow and ice covered surfaces

Measurements of NO and NO₂ were made at a surface site (55.28 °N, 77.77 °W) near Kuujjuarapik, Canada during February and March 2008. NO_x mixing ratios ranged from near zero to 350 pptv with emission from snow believed to be the dominant source. The amount of NO_x was observed to be dependent on the terrain over which the airmass has passed before reaching the measurement site. The 24 h average NO_x emission rates necessary to reproduce observations were calculated using a zero-dimensional box model giving rates ranging from 6.9 × 10⁸ molecule cm^?2 s^?1 to 1.2 × 10⁹ molecule cm^?2 s^?1 for trajectories over land and from 3.8 × 10⁸ molecule cm^?2 s^?1 to 6.6 × 10⁸ molecule cm^?2 s^?1 for trajectories over sea ice. These emissions are higher than those suggested by previous studies and indicate the importance of lower latitude snowpack emissions. The difference in emission rate for the two types of snow cover shows the importance of snow depth and underlying surface type for the emission potential of snow-covered areas.