Environmental economics models are often too complex to be communicated in an illustrative manner. For this reason, this paper develops the Basic Climate Economic (BCE) model that features core elements of macroeconomic and climate economic modelling, while allowing for an illustrative examination of the development path. The BCE model incorporates fossil stock depletion, pollution stock accumulation, endogenous growth, and climate-induced capital depreciation. We first use graphical analysis to show the effects of climate change and climate policy on economic development. Intuition for the different model mechanisms, the functional forms, and the effects of different climate policies is provided. We then show the model equations in mathematical terms to derive closed-form solutions and to run model simulations relating to the graphical part. Finally, we compare our setup to other models of climate economics.

Sexual differences in behaviours are often affected by the difference in individual interests between the sexes: growth in males and egg production in females. Some hermit crabs show sexual differences in shell use patterns during the reproductive season. In the non-reproductive season, however, when both sexes are focused on increasing growth, this sexual difference is expected to be reduced. In this study, we compared the pattern of shell use in the hermit crab Pagurus minutus between seasons, while focusing on the effects of shell shape on growth or egg production. As we predicted, sexual differences in shell use in P. minutus showed seasonal change. In the non-reproductive season, both sexes appeared to use shells well suited for growth. In the reproductive season, sexual differences became more evident, especially in larger solitary crabs and guarding pairs; males monopolized round-type shells such as those of Umbonium moniliferum, whereas more than 80% of females relied on high-spired Batillaria-type shells such as those of Batillaria zonalis. A lack of advantage for egg number in females using Batillaria-type shells suggests that female shell use is explained by factors other than maximizing clutch size. Both sexes can moult during the reproductive season, and larger body size is advantageous for reproduction. Given that Batillaria-type shells resulted in a lower growth increment and males have an advantage in shell fights in congeneric crabs, our findings suggest the importance of intersexual competition for shells and female compromise in determining the seasonal change of shell use patterns in P. minutus.

The enterprise budget, whole farm cash flow, and income statement are fundamental tools of farm and ranch management. The “Microcomputer Budget Management System” (MBMS) is a microcomputer software package that facilitates the storage and use of information for crop and livestock budgeting. It performs the calculations for several1 enterprise budgeting formats and for preparation of whole farm resource use reports and financial statements. The MBMS also includes internal machinery and irrigation cost calculation routines.

MBMS was developed for use by extension staff, researchers, lenders, consultants, and operators of diversified farms and ranches with many enterprises that use enterprise and whole farm budgeting for analysis and planning activities. The flexibility and detailed nature of the program requires the user to have knowledge of enterprise budgeting and operation of complex computer programs. This paper presents a discussion of the features and capabilities of the software and the computational procedures used in the cost calculations.

The landscape of U Minh in southern Vietnam contains the country's last remaining fragments of peat swamp forest and is home to several globally threatened species. Despite the presence of two national parks, evidence indicates that illegal natural resource use by local communities has had a significant effect on species populations. We investigated the nature and extent of natural resource use in U Minh. Interviews revealed that location is a significant determining factor in whether or not individuals choose to harvest resources, suggesting that the national parks are having some positive results in curtailing illegal harvesting. Most hunting and fishing is carried out for trade purposes and most interviewees indicated a preference for consuming livestock, suggesting that resource users do not rely on wildlife for subsistence but rather for supplementing their income. People who prefer consuming wild meat were found to be more likely to harvest natural resources than people who prefer consuming livestock, demonstrating a potential link between these behavioural issues. The preference for wild meat decreases with increasing price, in contrast with urban consumers who value more expensive wild meat varieties, which suggests that different factors are driving wild meat consumption among the rural Vietnamese. The majority of interviewees perceived a decrease in species populations, attributing the decline primarily to harvesting pressures and thus indicating that strict regulation of illegal harvesting activities is necessary to protect U Minh's remaining biodiversity.

Institutionalization of the Elderly in Canada suggested that efforts to address the underlying causes of age-related declines in health might negate the need for nursing homes. However, the prevalence of chronic disease has increased, and conditions like dementia mean that nursing homes are likely to remain important features of the Canadian health care system. A fundamental problem limiting the ability to understand how nursing homes may change to better meet the needs of an aging population was the lack of person-level clinical information. The introduction of interRAI assessment instruments to most Canadian provinces/territories and the establishment of the national Continuing Care Reporting System represent important steps in our capacity to understand nursing home care in Canada. Evidence from eight provinces and territories shows that the needs of persons in long-term care are highly complex, resource allocations do not always correspond to needs, and quality varies substantially between and within provinces.

The nursing home case-mix classification system, Resource Utilization Groups Version III (RUG-III), has been tested and refined for long-term home care clients. The study sample included 804 individuals seeking home care through the Michigan Care Management Program or the Home and Community Based Waiver for the Elderly and Disabled. Clients were classified, and RUG-III models were derived using the Minimum Data Set for Home Care (MDS-HC). A refined home care model, RUG-III/HC, was developed incorporating Instrumental Activities of Daily Living (IADLs) to the nursing home RUG-III classification. The model explained 33.7 per cent of the variance of per diem cost, using cost weighted formal and informal care as the dependent variable. Resource use within groups was relatively homogeneous. The case-mix index (CMI) of weighted formal and informal care time spanned an eight-fold range. Further analysis is suggested regarding the inclusion of informal care as a cost in case-mix classification for long-term home care clients.

Objectives: This study aims to compare the impact of two different sources of resource use, self-report versus care provider registrations, on cost and cost utility.

Methods: Data were gathered for a cost-effectiveness study performed alongside a 2-year randomized controlled trial evaluating the effect of an INTERdisciplinary COMmunity-based management program (INTERCOM) for patients with chronic obstructive pulmonary disease (COPD). The program was offered by physiotherapists, dieticians and respiratory nurses. During the 2-year period, patients reported all resource use in a cost booklet. In addition, data on hospital admissions and outpatient visits, visits to the physiotherapist, dietician or respiratory nurse, diet nutrition, and outpatient medication were obtained from administrative records. The cost per quality-adjusted life-year (QALY) was calculated in two ways, using data from the cost booklet or registrations.

Results: In total, 175 patients were included in the study. Agreement between self-report and registrations was almost perfect for hospitalizations (rho = 0.93) and physiotherapist visits (rho = 0.86), but above 0.55, moderate, for all other types of care. The total cost difference between the registrations and the cost booklet was 464 euros with the highest difference for hospitalizations 386 euro. Based on the cost booklet the cost difference between the treatment group and usual care was 2,444 euros (95 percent confidence interval [CI], −819 to 5,950), which resulted in a cost-utility of 29,100 euro/QALY. For the registrations, the results were 2,498 euros (95 percent CI, −88 to 6,084) and 29,390 euro/QALY, respectively.

Conclusions: This study showed that the use of self-reported data or data from registrations effected within-group costs, but not between-group costs or the cost utility.

Intercropping is the simultaneous cultivation of more than one crop species on the same piece of land and is regarded as the practical application of basic ecological principles such as diversity, competition and facilitation. Field experiments were carried out on a sandy loam soil and a sandy soil in Denmark over three consecutive cropping seasons including dual grain legume (pea, faba bean and lupin)–barley intercropping as compared to the respective sole crops (SC). Yield stability of intercrops (IC) was not greater than that of grain legume SC, with the exception of the IC containing faba bean. Faba bean and lupin had lower yield stability than pea and fertilized barley. However, the different IC used environmental resources for plant growth up to 50% (LER=0.91–1.51) more effectively as compared to the respective SC, but with considerable variation over location, years and crops. The SC performance supported the interspecific interactions within the IC stand. On the sandy loam 13% greater grain yield of pea cv. Agadir (520 g m−2) was observed as compared to cv. Bohatyr. Faba bean and lupin yielded similarly (340 g m−2) in the sandy loam soil, with decreasing yields on the sandy soil (320–270 g m−2). Nitrogen fixation was very constant in grain legume SC over species and location, varying from 13.2 to 15.8 g N m−2, being lowest in peas and highest in faba bean and lupin. The intercropped grain legumes increased the proportion of plant N derived from N2-fixation by on average 10–15% compared to the corresponding SC. However, especially lupin was suppressed when intercropping, with a reduced N2-fixation from 15 to 5–6 g N m−2. The IC were particularly effective at suppressing weeds, capturing a greater share of available resources than SC. Weed infestation in the different crops was comparable; however, it tended to be the highest in sole cropped faba bean, lupin and unfertilized barley, where the application of urea to barley reduced the weed infestation by around 50%. Reduction in disease was observed in all IC systems compared to the corresponding SC, with a general disease reduction in the range of 20–40%. For one disease in particular (brown spot on lupin) disease reduction was almost 80% in the IC. Intercropping practices offer many advantages but improved understanding of the ecological mechanisms associated with planned spatial diversity, including additional benefits with associated diversity, is needed to enhance the benefits achieved.

Various conservation models have been implemented in Nepal since 1973, however their impacts on resources use and conservation attitudes are scarcely known. To address the hypothesis that conservation attitudes should improve around protected areas (PAs) with more social and economic interventions, stratified random questionnaire surveys of 234 households were conducted in two PAs in the Western Terai of Nepal: Bardia National Park (BNP), in which interventions have been more widespread for longer time periods, and Sukla Phanta Wildlife Reserve (SWR), in which interventions are relatively recent. Both are part of a major landscape-level conservation programme under implementation in Nepal, and both are under threat of political turmoil, uncontrolled immigration, inefficient land reform policies and unsustainable resource use. There was spatio-temporal variability in resource use patterns and dependence. People collected eight and seven types of resources in BNP and SWR, respectively, and people in BNP were more dependent on resources overall. About 72% of respondents mentioned the problem of inadequate firewood, and suggested the promotion of alternative energy and permission to collect from PAs as mitigating strategies. Of 11 attitude statements, five significantly differed between the two areas. Respondents from the BNP had more favourable attitudes about conservation than those from SWR, supporting the main hypothesis. Training received by respondents, damage by wildlife, dependence on resources and satisfaction towards user groups contributed significantly to the variation in conservation attitudes. The results suggest that the liberalization of PA management has enabled the use of resources, improved livelihoods to some extent and solicited more favourable conservation attitudes in Nepal.

Northern (Macronectes halli) and southern (M. giganteus) giant petrels breed at different times at sub-Antarctic Marion Island. Long-term census and breeding success data are used to test for competitive overlap between the two species by correlating population trends with those of land-based prey/carrion species. No parameter was singularly important in population regulation of either giant petrel species and the assumed dependence of breeding northern giant petrels on southern elephant seal Mirounga leonina carrion is not entirely supported.

Background and objectives: Until recently, attention and treatment strategies have focused mainly on patients in the early phases of Alzheimer's disease (AD). The objectives of this study were to collect information on moderately severe and severe AD patients (Mini-mental State Examination score < 15) in terms of epidemiological, clinical and economic characteristics and disease change in the later stages of AD, and to compare this specific AD population over 6 months with those in the earlier stages.

Methods: This descriptive analysis recruited institutionalized patients and patients living within the community from the city of London and the South-East region of the U.K. Subgroup analyses at baseline and 6 months were performed using the study population from the London and South-East Region Alzheimer's Disease (LASER-AD) Study. Data from a range of clinical scales, a quality of life (QOL) scale and a resource-utilization questionnaire were analyzed.

Results: People with moderately severe or severe AD are a heterogeneous group with varying QOL, cognitive and functional disabilities, neuropsychological symptoms and relatively low health care resource consumption. This patient group continued to decline but progression of the disease was observed only in some domains.

Conclusion: Even at the later stages of AD, patients show varying rates of decline. Improved knowledge about the characteristics and progression of the disease reveals that moderately severe and severe patients cannot be regarded as beyond help and have the potential to experience varying and even high levels of QoL.

We studied the spatial and temporal habitat use of impala in Botswana's Okavango Delta at landscape level with the aid of satellite imagery, with minimal fieldwork. We related remotely sensed vegetation to impala habitat preferences, by first distinguishing three vegetation types through a multi-temporal classification, and dividing these into subclasses on the basis of their Normalized Difference Vegetation Index (NDVI). This indicator for abundance and greenness of biomass was assessed for wet and dry season separately. Similarly, habitat use was assessed for both seasons by allocating vegetation classes to bimonthly impala observations. Impala distribution patterns coincided with NDVI-based subclasses of the landscape, nested within broad vegetation types, to which impala did not show a marked seasonal response. We suggest that this methodology, using limited field data, offers a functional habitat classification for sedentary herbivores, which appears particularly valuable for application in extensive areas with high spatial variability, but with restricted access.

For many tropical forests a tendency for fruit production to fluctuate seasonally has been established, with pronounced peaks of abundance and periods of fruit scarcity during which a few important resources maintain frugivore communities. However, there is a lack of studies in subtropical forests on community phenology and on the identification of important resources. In this study, community-wide fruit availability and its use by the local frugivore community was investigated in the subtropical coastal dry forest of Oribi Gorge Nature Reserve, South Africa over 13 mo from July 1997 to July 1998. Along 19.5 km of phenology trails, 940 individuals of 96 plant species bearing fleshy fruits were monitored twice per month and fruit-eating animals observed. Although some fruit was available all year round richness of both fruiting species and fruit abundance showed a seasonal pattern with peaks at the end of August to beginning of October (i.e. before the rainy season) and March to May (i.e. after the rainy season). Periods of fruit scarcity were found in July and August (i.e. during the long dry season) and in November and December (i.e. during the rainy season). Fruits of 23 plant species were observed being eaten by 18 species of bird and two of monkey. Highest animal numbers were attracted by Ficus thonningii, a species that fruited asynchronously during most of the year and during periods of fruit scarcity, and provided high overall fruit biomass. The importance of this species as a potential keystone resource for the frugivore community is discussed.

Nepal has a number of wetlands in the lowland region of the country along the southern Indo-Nepalese border that have experienced great pressures from growing human populations due in part to migration of people from the mountains. A questionnaire survey and informal interviews with key informants in 1998 were used to explore the socio-economic status of indigenous and non-indigenous inhabitants, use patterns of forest and wetland resources and attitudes about conservation in Ghodaghodi Lake, a proposed Ramsar site, in the lowlands of western Nepal. Tharus, indigenous to the region, represented 33% of the population; the rest were migrants from the mountains. Tharus had lower literacy rates, larger landholdings and kept different livestock species. Most Tharu families were dependent on extraction from wetlands; all groups used forests for fuelwood but mountain settlers used forests for fodder more than did Tharus. Most respondents expressed willingness to participate in the conservation of Ghodaghodi Lake; however, only 12%, mostly mountain settlers, had ever participated in formal conservation activities. Conservation attitudes were strongly influenced by educational level and resource use. Educated males of higher caste and mountain origin who had previously participated in formal management activities were more positive towards conservation than other groups. There is a need to implement a participatory integrated management plan, to include community development, education and off-farm income generation, to assure participation of Tharus and lower caste households of mountain origin in the conservation and management of wetlands and forests in the area.

Participation by local communities in management is widely considered a means of sustaining protected areas. In parts of the world with a history of armed conflict, the chances of such an approach being successfully adopted might seem remote. One such area is the Maputo Elephant Reserve in southern Mozambique. The aim was to improve understanding of the local people's use of natural resources and perceptions of the Reserve's impact. Interviews and questionnaires distributed in four different villages were used to estimate the relative value of these resources in relation to the attitude of the local people towards the Reserve. The people gave a relative value rank for each specific use of each plant, animal and fish resource. On average 60% of the households exploited more than two different resource categories. The plant resources of the Reserve were used by 71% of the households and were valued more highly than animal and fish resources. Plants were used for many purposes; construction material, fuelwood and fruits had the highest relative values. Antelopes, hippopotamus and elephants were valued highest amongst a range of animal species which were hunted by 21% of households. Amongst uses of animals, consumption, use of the skins and commercial sale of the meat were especially important. When asked if they liked the Reserve, 88% of respondents answered positively. The attitude towards the Reserve was correlated with crop damage experiences; people with crop damage caused by elephants, hippos or bushpigs, were more negative. Attitude of respondents was inversely related to the number of species invading their agricultural fields. Resource use intensity, use purpose, resource value and attitude were different amongst sites and dependent on site-specific circumstances, different management strategies could be necessary for the four sites. A resource management plan should be drawn up, local people should be included in the management team and steps should be taken to improve the relationship between the Reserve's authorities and the local population generally.

The hypothesis of attaching and realising market values as one means of conserving biodiversity has gained ground over the last decade. This has been challenged recently after examination of a number of case studies, largely from tropical Amazonia, on high value logging, marketing of non-timber forest products, and bioprospecting. The conclusion was that market-orientated conservation has seldom generated the financial returns envisaged, and as such cannot be used as an incentive to prevent land transformation. This paper reviews the basis of the challenge to market-orientated conservation on a number of grounds, drawing on examples largely from southern Africa. It concludes that generalizations from tropical Amazonia regarding the failure of market-orientated conservation are probably premature, and that it should remain an option, amongst a number of options, for conservation of biodiversity. Additionally, the prerequisite criteria identified as necessary to create an enabling framework for the success of market-orientated conservation are insufficient. Case studies are presented where the prerequisites do not apply, yet current extraction for market purposes is sustainable. Other potential prerequisites are also considered. There is a need for multivariate analysis, based on a large sample size drawn from across a range of environments and resources, of which factors are important prerequisites for successful market-orientated conservation, and under which circumstances.

A key element of most recently proposed plant strategy schemes is an axis of resource capture, usage and availability. In the search for a simple, robust plant trait (or traits) that will allow plants to be located on this axis, specific leaf area is one of the leading contenders. Using a large new unpublished database, we examine the variability of specific leaf area and other leaf traits, the relationships between them, and their ability to predict position on the resource use axis. Specific leaf area is found to suffer from a number of drawbacks; it is both very variable between replicates and much influenced by leaf thickness. Leaf dry-matter content (sometimes referred to as tissue density) is much less variable, largely independent of leaf thickness and a better predictor of location on an axis of resource capture, usage and availability. However, it is not clear how useful dry matter content will be outside northwest Europe, and in particular in dry climates with many succulents.