Reduce Loss Rate Research Articles

Monitoring global rates of biodiversity change: challenges that arise in meeting the Convention on Biological Diversity (CBD) 2010 goals.

By agreeing to strive for 'a significant reduction in the current rate of loss of biological diversity' by the year 2010, political leaders at the 2002 World Summit on Sustainable Development (held in Johannesburg, South Africa) presented conservation scientists with a great opportunity, but also one of their most significant challenges. This is an extremely exciting and laudable development, but this reporting process could be made yet more powerful if it incorporates, from the outset, independent scientific assessment of the measures, how they are analysed, and practical ways of plugging key gaps. This input is crucial if the measures are to be widely owned, credible and robust to the vigorous external scrutiny to which they will doubtless be exposed. Assessing how rates of biodiversity loss have changed from current levels by 2010 will require that a given attribute has been measured at least three times; however, most habitats, species, populations and ecosystem services have not been assessed even once. Furthermore, the best data on which to base estimates of biodiversity loss are biased towards the charismatic vertebrate species; unfortunately, these supply minimal services to the human economy. We have to find ways to redress this taxonomic imbalance and expand our analyses to consider the vast diversity of invertebrate, fungal and microbial species that play a role in determining human health and economic welfare. In the first part of this paper I will use examples from local and regional monitoring of biological diversity to examine the desired properties of 'ideal indicators'. I will then change focus and examine an initial framework that asks how we might monitor changes in the economic goods and services provided by natural ecosystems. I will use this exercise to examine how the set of possible indicators given by the Convention on Biological Diversity might be modified in ways that provide a more critical assay of the economic value of biological diversity. Here I will emphasize that we need not only to monitor these benefits, but also to significantly increase public awareness of human dependence upon the role that non-voting species play in driving the world's financial economy.

Biological diversity

Biological diversity

Rate and mechanism of maximal oxygen consumption decline with aging: implications for exercise training.

Because of the influence of cardiorespiratory fitness on functional independence, quality of life, and cardiovascular disease and all-cause mortality, tremendous interest has been directed towards describing the age-related change in maximal oxygen consumption (VO(2max)). Current evidence supports a 10% per decade decline in VO(2max) in men and women regardless of activity level. High-intensity exercise may reduce this loss by up to 50% in young and middle-aged men, but not older men, if maintained long term. Middle-aged and older women do not appear to be able to reduce loss rates in VO(2max) to less than 10% per decade, which may be related to estrogen status. However, maintaining high-intensity training seems limited to approximately one decade at best and to a select few individuals. While the factors limiting the ability to maintain high-intensity training are not completely known, aging most likely plays a role as studies have demonstrated that training maintenance becomes more difficult with advancing age. Age-related loss of VO(2max) seems to occur in a non-linear fashion in association with declines in physical activity. In sedentary individuals, this non-linear decline generally occurs during the twenties and thirties whereas athletic individuals demonstrate a non-linear decline upon decreasing or ceasing training. Non-linear loss rates are also demonstrated in individuals over the age of 70 years. The decline in VO(2max) seems to be due to both central and peripheral adaptations, primarily reductions in maximal heart rate (HR(max)) and lean body mass (LBM). Exercise training does not influence declines in HR(max), while LBM can be maintained to some degree by exercise. Recommendations for exercise training should include aerobic activities utilising guidelines established by the American College of Sports Medicine for improving CV fitness and health, as well as strength training activities for enhancing LBM.

Effect of genotype, growth regulators, carbon source, and pH on shoot induction and plant regeneration in tomoto

Ten cultivars of tomato were screened for their ability to produce shoots and shoot primordia on media containing a range of 6-benzyladenine (BA) concentrations (0.0–4.0 mgl−1; 0.0–17.7 μM) in combination with indole-3-acetic acid (IAA; 0.0, 0.1, 0.2 mgl−1; 0.0, 0.57, 1.14 μM, respectively). Both genotypes and growth regulator levels showed significant differences at α=0.05. However, their interaction was not significantly different. A comparison of the mean number of shoots produced six cultivar classes, with UC82, UC97-3, Castlerock, Red Rock, and Peto86 producing the highest means. There were four cultiver frequency classes, the highest including cultivars Peto Rock (93.7%), Peto86 (92.3%), and Strain B (90.7%). Growth regulator mean comparisons produced eight classes, the highest included three different BA/IAA combinations, with media containing 2.0 mgl−1 (8.87 μM) BA and 0.2 mgl−1 (1.14. μM) IAA giving the highest mean and frequency (94.1%). The effect of carbon source was studied using glucose, fructose, maltose, and sucrose at 3.0% concentration. Three high regenerating genotypes and four media were used in combination with each sugar. Sugars were significantly different with maltose giving the highest number of shoots (31.6) followed by glucose (20.9). Growth regulator means, sugar-growth regulator interaction, and cultivar-sugar interaction were significant. A three-way interaction was nonsignificant. The effect of maltose and sucrose concentration (1.5–9.0%) showed the positive effect of maltose over sucrose in inducing shoots and in reducing loss rates of shoots on the regeneration media. Maltose at 1.5, 3.0, and 4.5% was the most effective. Six pH values (4.0–6.5) were used to test their effect on shoot induction in three cultivars (Peto86, UC97-3 and Castlerock). pH effects and cultivar-pH interaction were not significant.

Building efficient wireless sensor networks with low-level naming

In most distributed systems, naming of nodes for low-level communication leverages topological location (such as node addresses) and is independent of any application. In this paper, we investigate an emerging class of distributed systems where low-level communication does not rely on network topological location. Rather, low-level communication is based on attributes that are external to the network topology and relevant to the application. When combined with dense deployment of nodes, this kind of named data enables in-network processing for data aggregation, collaborative signal processing, and similar problems. These approaches are essential for emerging applications such as sensor networks where resources such as bandwidth and energy are limited. This paper is the first description of the software architecture that supports named data and in-network processing in an operational, multi-application sensor-network. We show that approaches such as in-network aggregation and nested queries can significantly affect network traffic. In one experiment aggregation reduces traffic by up to 42% and nested queries reduce loss rates by 30%. Although aggregation has been previously studied in simulation, this paper demonstrates nested queries as another form of in-network processing, and it presents the first evaluation of these approaches over an operational testbed.

When gauges fail and clouds are tall, we miss the horizon most of all: General Aviation pilot responses to the loss of attitude information in IMC

Sixty pilots were exposed to a vacuum-system failure during a flight simulation, 48 in a Piper Malibu simulator and 12 in a simulated Cessna 172. Instrumentation failure was varied for the five display configurations such that 12 pilots (1) lost head-down heading and attitude indicator (AI), (2) lost only the primary AI (horizontal situation indicator, HSI, was electric), (3) lost the primary AI but had the HSI plus a back-up electric AI, (4) lost the AI and directional gyro (DG), or (5) lost the AI but had an HSI (only in the Cessna 172 simulator). Primary panel (loss of AI and DG) showed the highest loss rate (83%). The proposed back-up AI in place of turn coordinator produced a 33% loss rate. Standard Malibu instrumentation (HSI) produced a 25% loss rate. Having all options (HSI, TC, back-up AI) reduced loss rate to just 8%. Data suggest that the presence of a back-up attitude indicator can ameliorate the rate of loss of control, but that the presence of the HSI had a similar effect. Combining the two produced the best outcomes. Results are discussed in relation to potential interventions, including attitude and heading indicators and annunciators for system failure.

Loss rates of butterfly species with urban development. A test of atlas data and sampling artefacts at a fine scale

Data for the United Kingdom (UK) Manchester Butterfly Atlas produced conflicting species loss rates for increased urban development. In particular, a very low rate of loss was recorded (0.19 species for every 10% increase in urban cover) for the Mersey Valley mapped at a high resolution of 1 ha units. It was suggested that sampling artefacts (uneven recording) or failure to distinguish vagrant individuals from breeding populations cause this. Herein, results are reported for 30 sample squares, within the Mersey Valley, surveyed uniformly throughout 1999. It is shown that loss rates are as high as areas mapped at lower resolution over wider areas (0.67–0.68 species for every 10% increase in urban cover) and that increasingly stringent definitions of urban cover result in higher loss rates. Comparison with the data from the Atlas, but for the same 30 sample squares, indicate that the low rates at a fine scale for the complete Atlas data are more likely to be caused by uneven recording than from failure to record species status. However, progressive sampling of squares, despite uniform recording, will inevitably cause a reduction in loss rates of total species for increases in urban development.

Consequences of phenotypic plasticity vs. interspecific differences in leaf and root traits for acquisition of aboveground and belowground resources

Trade-offs between acquisition capacities for aboveground and belowground resources were investigated by studying the phenotypic plasticity of leaf and root traits in response to different irradiance levels at low nutrient supply. Two congeneric grasses with contrasting light requirements, Dactylis glomerata and D. polygama, were used. The aim was to analyze phenotypic covariation in components of leaf area and root length in response to above- and belowground resource limitation and the consequences of this variation for resource acquisition and plant growth. At intermediate shading (30 and 20% of full sunlight) the plants were able to maintain their total root length, despite a strongly increased total leaf area and a reduced biomass allocation to roots. This was associated with an unaltered or slightly increased nutrient uptake and growth. At 5.5% relative irradiance, growth was severely reduced, especially in the shade-tolerant D. polygama. The results show that constraints on acquisition capacities for aboveground and belowground resources, caused by biomass allocation, may be alleviated by plasticity in other traits such as tissue-mass density and thickness of roots and leaves. The results also suggest different adaptive constraints for phenotypic plasticity and for genetically determined interspecific variation. Phenotypic plasticity tends to maximize resource acquisition and growth rate in the short term, whereas the higher tissue-mass density and the longer leaf life-span of shade-tolerant species indicate reduced loss rates as a more advantageous species-specific adaptation to shade in the long term.

Energetics and growth kinetics of a deep Prochlorococcus spp. population in the Arabian Sea

During the US JGOFS process studies in the Arabian Sea (1995), secondary fluorescence maxima (SFM) were observed frequently at the oxic–anoxic interface at the extreme base of the euphotic zone. These secondary peaks were most prominent during the early NE monsoon in the central oligotrophic portion of the Arabian Sea, although they were spatially and temporally variable. Based on high performance liquid chromatography (HPLC) and flow cytometry analyses, SFM were determined to be populated almost exclusively by the marine cyanobacterium Prochlorococcus spp. While SFM were about half the magnitude of primary fluorescence peaks, chlorophyll a biomass was typically an order of magnitude less than at the primary maxima (although total chlorophyll ( a+ b) differed only by a factor of two). Photosynthesis versus irradiance response curves revealed an efficient population adapted to extremely low light (∼0.02–0.05% surface irradiance) largely through increased light absorption capabilities. A theoretical spectral irradiance absorption efficiency model based on available spectral irradiance, individual cell properties, and bulk particulate spectral absorption also supports a well-adapted low-light population. Deck-incubated C-14 uptake as well as dilution growth experiments revealed instantaneous growth rates on the order of μ=0.01 d −1. However, additional in situ observations suggest SFM populations may be more dynamic than the growth rates estimates from shipboard bottle incubations predict. We advance four hypotheses for the regulation of SFM populations including: (1) reduced loss rates, (2) discontinuous environmental conditions, (3) enhanced sub-oxic growth, and (4) physical mechanisms.

The effect of ACE inhibitors and other antihypertensive agents on insulin resistance

stenosis. For the individual patient rather than the individual kidney the outcome will depend on the patency of the contralateral renal artery. An intervention to decrease the rate progression of both the renal artery lesion and the decline in renal function in an individual kidney would appear attractive. At the present time there are no prospective studies to support either surgical or angioplasty intervention demonstrating increased longevity or reduction in rate of loss of renal function. Studies are, however, under way which may answer this question. The decision to perform angioplasty in a kidney with 60% or greater renal artery stenosis would appear reasonable as the likelihood of progression is high. This decision cannot be supported as yet by any outcome data in terms of patient survival or stabilization of renal function. In dialysis-dependent patients and those with 'flash pulmonary oedema' there are clear indications for intervention and not the 'wait-and-see' approach. The difficult group is those patients picked up on routine angiography of another vascular bed. It is tempting to suggest that measures such as low-dose aspirin and/or lipid-lowering therapy should be used in these patients. No studies have addressed this problem, and the 'waitand-see' approach may be entirely appropriate in the asymptomatic patients until data can demonstrate an improved outcome on therapy. 589

The Struck-and-lost Factor in Alaskan Walrus Harvests, 1952-1972

Struck-and-lost rates during hunts for walruses, Odobenus rosmarus (Linnaeus), in Alaska from 1952 to 1972 did not vary from year to year. On average, 42% of the animals struck by bullets were lost (i.e., not retrieved). About 55% of the struck-and lost animals died immediately; the rest were wounded. Apparently, most of the wounded died soon after they were struck. The sex-age composition of the struck-and-lost animals was about the same as that in the harvest, and the proportion lost did not vary with the size of the group encountered. Claims of reduction in loss rates in recent years, based on improved firepower, are open to question. Considerable improvement in weapons took place also during the 21-year period of this study, but it merely increased the proportion of outright kills among the struck-and-lost animals. It did not reduce the proportion lost of the animals that were struck. Key words: walrus, Odobenus rosmarus , Alaska, harvests, struck-and-lost

Does microbial biomass affect pelagic ecosystem efficiency? An experimental study

Bacteria and other microorganisms in the pelagic zone participate in the recycling of organic matter and nutrients within the water column. The microbial loop is thought to enhance ecosystem efficiency through rapid recycling and reduced sinking rates, thus reducing the loss of nutrients contained in organisms remaining within the photic zone. We conducted experiments with lake communities in 5400-liter mesocosms, and measured the flux of materials and nutrients out of the water column. A factorial design manipulated 8 nutrient treatments: 4 phosphorus levels × 2 nitrogen levels. Total sedimentation rates were greatest in high-N mesocosms; within N-surplus communities, [Symbol: see text]1 µM P resulted in 50% increase in total particulate losses. P additions without added N had small effects on nutrient losses from the photic zone; +2 µM P tanks received 334 mg P per tank, yet after 14 days lost only 69 mg more particulate-P than did control communities. Nutrient treatments resulted in marked differences in phytoplankton biomass (twofold N effect, fivefold P effect in +N mesocosms only), bacterioplankton densities (twofold N-effect, twofold P effects in -N and +N mesocosms), and the relative importance of autotrophic picoplankton (maximum in high NY mesocosms). Multiple regression analysis found that of 8 plankton and water chemistry variables, the ratio of autotrophic picoplankton to total phytoplankton (measured as chlorophyll α) explained the largest portion of the total variation in sedimentation loss rates (65% of P-flux, 57% of N-flux, 26% of total flux). In each case, systems with greater relative importance of autotrophic picoplankton had significantly reduced loss rates. In contrast, greater numbers of planktonic bacteria were associated with increased sedimentation rates and lower system efficiency. We suggest that different microbial components may have contrasting effects on the presumed enhanced efficiency provided by the microbial loop.

Patterns of production and sedimentation in the boreal and polar Northeast Atlantic

Pelagic systems are potentially capable of retaining and recycling all autochthonous organic material, although some losses due to sinking particles inevitably occur. Relating processes in the surface layers quantitatively to vertical particle flux is difficult because only a small percentage of the total production is lost annually via sinking in the open ocean. Further, only a few types of particles contribute to this flux and only a smalt proportion of these may actually reach greater depths. Measurements of vertical flux with sediment traps revealed seasonal and regional patterns also within the northwestern Atlantic and indicate imbalances between particle formation and degradation. The classical pattern of spring bloom sedimentation followed by reduced loss rates has been found in shelf and shallow water regions such as the Norwegian Coastal Current and fjords and is also encountered in the Barents Sea. In the Norwegian Sea. however, the seasonal pattern appears different as the seasonal maximum has been observed during late summer/autumn. The physical environment determines nutrient availability and hence the particles potentially available for sedimentation. The relationship between phyto- and zooplankton governs vertical flux seasonality, and zooplankters with different life cycles and feeding strategies further modify the principle patterns. Herbivores with life-cycle strategies involving overwintering of large biomass and predictable seasonal appearance (copepods, cuphausiids) will have a different impact than opportunistic organisms with very low overwintering biomass, for example salps and ptcropods. The latter exhibit much greater interannual biomass variation and may thus contribute to interannual variability of the vertical flux. Shelf systems of similar latitude arc generally comparable with respect to their flux patterns and also share similarities with marginal ice zones. Open ocean systems as the Norwegian Sea, however, exhibit different patterns which are similar to the subarctic Pacific.

Processing of gel-silica monoliths for optics: Drying behavior of small pore gels

Processing and optical properties of fully dense sol-gel derived silica, termed Type V Gel-Silica, are described. Drying of large optically transparent acid-catalyzed alkoxide derived monolithic silica xerogels is emphasized. Changes in the weight, dimensions and optical properties are monitored during drying which allows a quantitative analysis of the drying process to be made. Results show three stages of drying. Stage 1. Where the greatest changes in volume, weight and structure occur. This stage is controlled by evaporation from the surface of the body and ends when shrinkage ceases. There is no constant rate period of drying but a progressive reduction in loss rate as the average pore radius decreases from 3.9 nm to 2.3 nm. Stage 2. Where changes in weight and volume are small but large changes in optical characteristics occur. This opaque stage is controlled by flow through small pores and liquid layers over the pore surfaces. Most of the pore emptying occurs during this stage. Stage 3. Where there are no further dimensional changes, but a progressive loss of weight occurs until equilibrium is reached. This stage starts when ∼ 94% of the liquid has been removed. Liquid pathway to the surface become discontinuous, and the remaining liquid can only be removed by evaporation within the pores and diffusion of the vapor to the surface. After stabilization and densification the silica xerogel monoliths have a degree of homogeneity, purity and optical and thermal properties superior to other commercial optical silicas.

Studies on the Insulation of Greenhouses (1)

In order to compare the effect of several material curtains on reducing the heat requirement of a greenhouse, the overall heat transfer coefficient, k, was investigated with two small model green-houses (Fig. 1); One was covered with glass and the other with PVC film. Five material curtains (PVC, PE, Nonwoven polyester fabric, net and aluminum PE) were used to compare the ability of reduction in heat requirement.Experiments were carried out on several winter nights under natural weather conditions, and k was calculated from equation (1). Results obtained were as follows:(1) The values of k for the single glazing greenhouses indicated a correlation with the windspeed, w (Fig. 5).Glasshouse k=4.41+0.40wPVC house k=4.87+0.54w(2) The PVC and PE curtains with which no condensation occurred were examined for the effect on k in the glass and PVC houses (Fig. 7, 8).Glass+PVC k=2.93+0.10w+PE k=3.00+0.16wPVC+PVC k=2.91+0.14w+PE k=3.15+0.17wThe PE curtain which was the most transparent to thermal radiation indicated a larger k than the PVC curtain which had less transparency to thermal radiation.(3) When evaporation occurred, the value of k for the greenhouse with nonwoven fabric curtain which had vapor permeability was larger compared with no evaporation occurring (Fig. 10).(4) Aluminum PE curtain showed a high reduction of k. This result suggests that curtains which are reflective to thermal radiation are more effective in reducing heat losses in greenhouses.(5) PVC, PE, nonwoven fabric, net, and aluminum PE curtains in glasshouses showed a reduction in k at 1m/sec windspeed of 37%, 33%, 27%, 8%, and 58% respectively. PVC and PE curtains in the PVC house showed a heat loss reduction rate of 43% and 39%, respectively.

Radiometric studies of mercury loss from fungicidal paints. 1. Loss of phenyl mercuric acetate

AbstractExposure tests have been made on paint films prepared from an emulsion paint containing phenyl mercuric acetate (PMA) labelled with 203Hg. Loss of mercury from the films has been followed radiometrically.Films exposed indoors in a confined space (no air circulation) showed little, if any, mercury loss for up to 8 months. Films exposed in the open laboratory lost from 20 to more than 60% of mercury after 250 days. This agrees qualitatively with the results of other workers on similar paints. At 50°, films lost mercury at rates about 10 times greater than those at ambient temperature.Films exposed out‐of‐doors lost the majority of their mercury after a few days of rain. Pre‐treatment of films, e.g. by u.v. radiation, had no effect on their subsequent outdoor behaviour. Even well‐dried films lost mercury at the same rate as newly applied films.Films with a low PMA content (0·02% Hg) lost mercury at a higher percentage rate than films with a high one (0·2% Hg). Thick films (0·002 in.) lost mercury at a lower rate than thin ones (0·001 in.). A mercury‐free top coat also reduced loss rate. All loss rates decreased with increasing time. These trends applied to all the exposure conditions studied.Mercury loss appears to be due to both volatilisation and dissolution of PMA and not to decomposition. The results indicate a non‐homogeneous distribution of PMA throughout the paint film, and a diffusion‐controlled process.