Average Bill Research Articles

Sexing Black‐legged Kittiwakes by measurement

The effectiveness of using biometric data to sex Black‐legged Kittiwakes Rissa tridactyla in northeast England has been examined. No single measurement or group of measurements was successful in sexing all individuals. The head and bill length was the best measure and correctly sexed 94% of individuals. Mass was an unsatisfactory value to identify sex, as it varied with the time since feeding, throughout the season and probably between years. There was also a significant trend for older individuals to be heavier. Wing length showed considerable overlap between the sexes and both wear of the tip of the longest primary and age adversely influenced the reliability of this measure. There was no obvious or appreciable advantage in using a combination of measurements, such as wing length and head and bill length to produce a combined discriminant value, and the improvement in sexing was marginal and of dubious significance. The Kittiwake shows geographical variation in size and it is suggested that, in other areas, plus and minus 2.6 mm of the average head and bill length of the sample taken from that area will adequately estimate the mean head and bill lengths of male and female Kittiwakes respectively, while the overall mean approximates to the best separation value.

Economic valuation of health risk exposure of restaurant users in Dhaka city

The aim of the study presented in this paper is to estimate the economic cost of health risk exposure of the restaurant users in Dhaka city. In a large-scale survey, 400 restaurant users in Dhaka city belonging to lower-middle to high income group were asked for their preferences for a hypothetical ‘Food Safety Inspection Programme’ using closed ended dichotomous choice contingent valuation questions. The study reveals an average estimated willingness to pay of Tk31 (US$ 0.5) which is 13% of the average restaurant bill per visit per person. Aggregating the overall willingness to pay estimate across the whole population, a reduction in restaurant food-related health risk results in a total economic benefit of Tk2,250 million (US$33million) per year. The study, furthermore, reveals that the respondent' willingness to pay for the Inspection Programme varies with the degree of health risk exposure, respondent' income level, frequency of restaurant visits, the disutility from health risks and the levels of self-protection. Two different health risk indicators, subjective (respondent perceived probability of becoming ill after eating in a restaurant) and objective (experience of negative health incidences from low quality restaurant food), have been used to test the consistency of influence of health risk exposure on stated willingness to pay. Better model fit has been observed with the objective health risk exposure. The results from the statistical models indicate that the offered bid amounts (additional amount of money that the restaurant users need to pay in order to finance the Inspection Programme) affects willingness to pay negatively. We find income, frequency of restaurant visits and health consciousness influencing willingness to pay for the Inspection Programme positively. Finally, our results confirm the hypothesis that willingness to pay for health risk reduction varies positively with the levels of risk exposure independent of the type of indicators (subjective or objective) we use to measure health risk.

Evaluating Consumers’ Willingness to Pay for Improved Potable Water Quality and Quantity

The present research is about water supply shortages and low drinking water quality in the Municipality of Rethymno during peak water demand periods. More specifically, the aim of this work is to elicit Rethymno residents’ willingness to pay (WTP), by applying the CVM methodology, as the percent over their water bill, for the completion of future projects that the Municipal Enterprise for Water Supply and Sewerage (MEWSS) of Rethymno intends to implement to avoid shortages and improve tap water quality. The current contingent valuation study is performed based on data collected through personal interviews where respondents are asked about their WTP for a given improvement in the water supply. The results point out that female respondents, households with high income, with children, and households which do not use tap water for drinking, are on average willing to pay more. The mean WTP for these future projects was estimated to be 10.64 € (17.67% of the average bill). The mean WTP amount can be useful to decision makers undertaking an environmental cost benefit analysis, where full cost should be recovered. Interviewing people in the context of a valuation scenario, informs them for improvements that will be undertaken from the new projects under consideration and at the same time involves them as users in the decision making process.

Is the nominate subspecies of the common crossbillLoxia c. curvirostrapolytypic? II. Differentiation among vocal types in functional traits

Vocally differentiated common crossbillLoxia curvirostrapopulations (‘vocal types’) in North America show a high degree of morphological and ecological specialization coupled with significant genetic differentiation and appreciable levels of assortative mating in sympatry. Similar vocally differentiated common crossbill vocal types have recently also been uncovered in Europe. These vocal types frequently overlap in space and time, and preliminary data indicate strong assortatively mating in sympatry. These observations suggest that the European nominate subspecies also consists of several independent evolutionary lineages, but so far morphological and ecological support for this view has been lacking. Bill morphology of crossbills is tightly linked to resource use, and we earlier showed that average morphology (of birds of unknown vocal type) indeed differed among years, consistent with the possibility that vocal types are morphologically differentiated if the proportion of each type caught varies among years. Here we test specifically for morphological differences between birds assigned to vocal type, at two sites and during two independent influxes. Differentiation between the two vocal types studied is highly significant, with the same pattern uncovered at each site and for each influx. Of eight traits investigated, in both univariate and multivariate analyses, the trait that differs most between the two types is the ecologically important bill depth. The difference in average bill depth between these two European vocal types (0.26 mm) is equivalent to the difference between some ecologically specialised North American vocal types. These results provide further evidence that the nominate subspecies of the common crossbill consists of several ecologically distinct populations, if not cryptic species.

Royal Tern (Sterna maxima) Chick Diet at Fisherman Island National Wildlife Refuge, Virginia

Abstract Royal Tern (Sterna maxima) chick diet at Fisherman Island National Wildlife Refuge, Virginia, was investigated in 2003 and 2004. Primary objectives were to document common prey species, annual and seasonal variation in prey selection, and seasonal variation in prey size based on average bill length in this species. Over 2200 Royal Terns bred on this island each year of the study. Single items of prey species carried in the bill by adult terns feeding their chicks were identified using 8 × 42 binoculars. A total of 11,566 and 33,646 prey items were identified during 44 and 87.5 h of systematic observations in 2003 and 2004, respectively. Terns foraged largely on anchovy (Anchoa spp.) early in the season, then switched to herrings (Clupeidae); average prey size also increased seasonally each year. Prey switching was similar to that of Royal Terns in North Carolina (but with drum as well as herring), indicating regional adaptations to forage fish availability by this species along the mid-Atlantic s...

CAN SELECTION BY AN ECTOPARASITE DRIVE A POPULATION OF RED CROSSBILLS FROM ITS ADAPTIVE PEAK?

The bill structures of different call types of red crossbills (Loxia curvirostra complex) in western North America usually approximate the predicted optima for foraging on single species of conifers. One clear exception is the call type in the South Hills, Idaho, that is coevolving in an evolutionary arms race with Rocky Mountain lodgepole pine (Pinus contorta ssp. latifolia). Although South Hills crossbills forage only on the cones of these lodgepole pines, their average bill depth is smaller than that predicted to be optimal. Because preliminary data showed that large-billed males were more likely to exhibit symptoms of ectoparasitic mite (Knemidokoptes jamaicensis) infestation, the goal of our study was to further quantify the incidence of mite infestation and determine whether selection by mites may have favored smaller-billed crossbills and thus driven crossbills away from the foraging optimum. We estimated annual survival of both infected and uninfected South Hills crossbills using program MARK, which allows for auxiliary variables such as bill size and sex to be included in survival analyses. Mite infestation depressed crossbill survival and, especially for males, caused directional selection against larger-billed individuals. Such selection may explain why South Hills crossbills have smaller bills than the optimum and why average bill size for males has decreased from 1998 to 2003. This selection may also explain why the degree of sexual size dimorphism has decreased by nearly 50% since 1998.

A role for habitat area in the geographic mosaic of coevolution between red crossbills and lodgepole pine

Understanding how resource abundance limits adaptive evolution and influences species interactions is an important step towards developing insight into the role of microevolutionary processes in establishing macroevolutionary patterns. We examined how variation in resource abundance (forest area of lodgepole pine Pinus contorta ssp. latifolia) influenced patterns of co-adaptation and coevolution between red crossbill (Loxia curvirostra complex) and lodgepole pine populations. First, we found that crossbill abundance increased logarithmically as forest area increased in mountain ranges lacking a preemptive competitor (pine squirrels Tamiasciurus hudsonicus). Second, seed defences against predation by crossbills increased with increases in crossbill density, suggesting that seed defences have likely evolved in proportion to the intensity of selection that crossbills exert. Third, the average bill size of crossbill populations increased with increasing seed defences, which implies that crossbill offenses increased with increases in seed defences. The large bill size on the largest range is the result of coevolution with lodgepole pine with this crossbill population perhaps speciating. Local adaptation of crossbill populations on smaller ranges, however, is more likely the result of resident crossbills representing a subset of the potential colonists (phenotypic sorting) than of local evolution. In the smallest range, migration and possibly more frequent extinction likely impede local adaptation and may result in maladaptation.

CAN SELECTION BY AN ECTOPARASITE DRIVE A POPULATION OF RED CROSSBILLS FROM ITS ADAPTIVE PEAK?

The bill structures of different call types of red crossbills (Loxia curvirostra complex) in western North America usually approximate the predicted optima for foraging on single species of conifers. One clear exception is the call type in the South Hills, Idaho, that is coevolving in an evolutionary arms race with Rocky Mountain lodgepole pine (Pinus contorta ssp. latifolia). Although South Hills crossbills forage only on the cones of these lodgepole pines, their average bill depth is smaller than that predicted to be optimal. Because preliminary data showed that large-billed males were more likely to exhibit symptoms of ectoparasitic mite (Knemidokoptes jamaicensis) infestation, the goal of our study was to further quantify the incidence of mite infestation and determine whether selection by mites may have favored smaller-billed crossbills and thus driven crossbills away from the foraging optimum. We estimated annual survival of both infected and uninfected South Hills crossbills using program MARK, which allows for auxiliary variables such as bill size and sex to be included in survival analyses. Mite infestation depressed crossbill survival and, especially for males, caused directional selection against larger-billed individuals. Such selection may explain why South Hills crossbills have smaller bills than the optimum and why average bill size for males has decreased from 1998 to 2003. This selection may also explain why the degree of sexual size dimorphism has decreased by nearly 50% since 1998.

BIASES IN THE FIELD ESTIMATION OF SHOREBIRD PREY SIZES

Several studies have attempted to calculate the energy intake rates of shorebirds. One method of doing this involves estimating the size of prey items in relation to the bird's bill length, and then using an average bill length to convert this value to actual prey length in order to estimate prey mass/energy content. Although this technique is used regularly, no study has assessed under what conditions the method is reliable. Observer distance from the bird, prey type, size and orientation in the bill, bill length and shape, and light conditions may all affect the accuracy of the estimates. This study sought to establish the conditions under which the method is or is not reliable, using three different prey types (“thin” and “fat” polychaetes, and crabs) and a long- and short-billed bird. It was found that if observers were calibrated, and their results were corrected using regression analysis, errors in estimates of food intake were much reduced. The time allowed to view the prey significantly affected the error in the result, with shorter viewing time causing greater errors, and observations made into the light were less accurate than those made with the light behind the observer. Large prey types, or even larger size classes of the same species, are estimated less accurately than small prey, and accuracy decreases as prey size increases as multiples of bill length. If separate calibration regressions are generated for large and small prey, food intake estimates are more accurate than if a single regression is used incorporating the full range of prey sizes. Sexual dimorphism in bill length can also increase error in the results.

Factitious renal colic

Objectives We reviewed our experience with patients with factitious disorders who presented with renal colic to identify their common characteristics and to quantify the cost burden placed on the health care system as a result. Methods We retrospectively reviewed the medical records of two Philadelphia area hospitals from 1989 to 1995 to find patients with factitious disorders who presented with renal colic. A control group of patients with nephroureterolithiasis was also identified. Results We identified 12 patients who presented with renal colic and had a final diagnosis of Munchausen's syndrome or malingering. The incidence of factitious renal colic was 0.6%. Eighty-three percent of these 12 patients were men, had an average age of 32 years, and made a total of 18 hospital visits. Ninety-two percent claimed an intravenous contrast allergy, 25% claimed an allergy to a specific narcotic, and 39% of the hospital visits ended with the patient voluntarily discharged against medical advice. Thirty-three percent were treated elsewhere for similar complaints. Only the number of intravenous contrast allergies and the number of patients leaving against medical advice were statistically different from the control group. The total cost for all factitious visits was $52,452, with a mean cost per visit of $2914. The average bill of those patients who received retrograde pyleograms was $3046 greater than for those who did not. Conclusions Factitious disorders should be considered when evaluating patients with an intravenous contrast allergy and renal colic. These patients are likely to leave against medical advice and place a significant cost burden on hospitals.

Optimal advance payment scheme involving fixed per-payment costs

The advance payment scheme is used when a payment larger than the billed amount is made. The extra payment is effectively a cash deposit for credit towards bills in future periods. This study presents a model for determining the optimal cash deposit amount when there is a fixed per-payment cost; the model balances the tradeoff between the fixed payment cost with the lost interest on the cash deposit. We use a renewal theory approach to obtain the long-term expected total cost per period when the bill amounts in a future period are deterministic, exponentially distributed, normally distributed, or Poisson occurrence based with a constant per occurrence charge. For the first two cases, we obtain explicit expressions for the optimal deposit amount; for the latter two, we give numerical procedures. An example in each case is presented, along with a comparison with the usual pay-each-period strategy. We conclude that the advance payment strategy offers significant cost savings when the per-payment cost is relatively large compared with the lost interest of one period's average bill amount; i.e. when interest rate is low or the average bill amount is small.

Variability in seed size selection by granivorous passerines: effects of bird size, bird size variability, and ecological plasticity.

The niche variation hypothesis predicts a direct relationship between intraspecific variability in feeding ecology and the variability of the morphological traits related to feeding behaviour. The following study tests this prediction by measuring in captivity the seed size preferences and the morphology of 9-11 individuals of seven specialized granivorous bird species. The average seed size preferences of these birds have previously been shown to be related to components of bill size. The ranges of seed sizes selected were related to the mean bill sizes of birds in a way that paralleled the patterns found when analysing average values. Bill and body size variability were not related, however, to the range of seed preferences after controlling for the significant mean-variance relationship showed by morphological traits. Thus, results do not support the niche variation hypothesis. the significant effect of average bill size on diet variability was consistent with the direct relationship between bird size and ecological plasticity expected on the basis of the shape of the family of functions relating seed size and seed profitability for different-sized birds. These findings suggest morphological mechanisms for ecological plasticity whose generality and evolutionary significance merit further research.

Annual Variation of Primary Molt with Age and Sex in Cassin's Auklet

Annual Variation of Primary Molt with Age and Sex in Cassin's Auklet

Impact of Conservation on Rates and Operating Costs

The potential impact of 20% reduction in water usage through water conservation is investigated for a small investor owned utility serving the rural residential community of Stewartstown Borough, Pennsylvania. The analysis of short‐term impact shows that the average bill would be reduced by 16% if rates had not been changed; however, the company's operating expenses would only have been reduced by 2%. The long‐range impact is investigated using present worth analysis, A 20% reduction in water use would have saved $71,280 in present worth (1976) for storage and source facilities and operating costs. The savings in capital and O&M costs would eventually translate into savings in water bills of the customers over the years.

The Impact of Municipal Water Quality Improvements on Household Water Bills

ABSTRACT As drinking water contamination problems become more prevalent, many cities will have to undertake additional water treatment or other contaminant removal measures. This paper examines the impacts of a range of water treatment techniques on the cost, price, and usage of water by households to determine the impact of such treatments on water bills. Data on costs are taken from pilot studies and case studies in the United States. Utility costs and pricing behavior and residential usage are determined from an econometric model of the water industry. The impact of the treatments on water system costs can be large but because people are likely to reduce usage as prices rise, the impact on household water bills is dampened. The average water bill will still be below $300 per year (in 1980 dollars) in even the most extreme cases examined and the bill may remain below $100 per year.

Outpatient meniscectomy of the knee.

This paper reviews 218 patients who had outpatient meniscectomy at the University of Virginia between January 1974 and June 1977. Only one patient (0.46%) returned before his scheduled visit. Three patients (1.4%) had superficial wound infections. One (0.46%) had a pulmonary embolus several weeks postoperatively. Twelve percent underwent knee aspiration at two weeks after operation and 3.8% at six weeks. Twenty-seven patients had two meniscectomies at the University of Virginia, and 23 had both procedures as outpatients. None who had the first as an outpatient chose admission for the second. The average hospital bill for meniscectomy performed at a private hospital in Virginia in 1978 was +1,238.99. This would have been reduced by about 50% if meniscectomy had been done on an outpatient basis. In selected patients, outpatient meniscectomy can be done with a low complication rate, at a decreased cost, and with satisfaction to the patient and doctor.

The cost effectiveness of therapeutic and prophylactic leukocyte transfusion.

We analyzed the cost effectiveness of leukocyte transfusion in preventing death from infection during intensive chemotherapy for acute leukemia. Effectiveness was estimated with an odds-ratio analysis based on published results of controlled studies of therapeutic and prophylactic leukocyte transfusion. Cost estimates were based on blood-bank charges throughout the country. Calculations of effectiveness suggest that leukocyte transfusion might prevent 50 to 75% of early deaths from infection. Therapeutic transfusion would add approximately 10.9% to the hospital bill of the average bill of the average leukemic patient and cost $17.7 million annually nationwide. Prophylactic transfusion would add 35.2% to the hospital bill and cost $57.8 million annually. Mean cost-effectiveness ratios were $14,982 per life-year for therapeutic transfusion and $35,020 to $50,029 per life-year for prophylactic transfusion. The cost per additional life-year achieved with prophylactic rather than therapeutic leukocyte transfusion was $85,291. These data suggest that leukocyte transfusion is an extremely expensive technologic procedure.

The Cost of Coronary Bypass Procedures

We reviewed the financial records of 200 succesive patients who had coronary artery bypass surgery in the first three months of 1976. The average hospital bill was $7,690 and the average length of stay was 18 days. The highest bill was $28,329 (79 days) and the lowest was $6,126 (11 days). The average total physician charge to the patient was $3,240. The total average hospital and physician cost was $10,930.

Tennessee Rate Changes Since 1947

The report demonstrated that, in theory, few Tennessee communities charged adequately for the water service they were rendering. Although national experts in the field of water rates, for example, agreed that the cost of supplying 2,500 gal. to a customer in a community of under 1,000 population should average from $3.00 to $3.50 a month, in Tennessee the average bill was only $1.74, with rates ranging from $1.00 to $2.75 a month for the same population bracket.