Uninterrupted Increase Research Articles

EFFECT OF DEBT SERVICE ON INFRASTRUCTURAL DEVELOPMENT IN NIGERIA

The study examines the effect of debt services on infrastructural development in Nigeria. The increase in debt services has been worrisome; recently Nigeria’s debt service has astronomically increased without interruption. This uninterrupted increase of debt service has resulted to decrease in infrastructure, consequently, decreasing private investment and aggregate demand, thus, increasing unemployment in the country. The study employed an econometric model to test a long run relationship between debt services and infrastructural development and found a long run relationship. The study also found a negative and statistically significant relationship between debt services and infrastructure in Nigeria. Based on the findings, the study recommended that government should look for alternative means of raising fund rather than borrowing.

Machine Learning and statistic predictive modeling for road traffic flow

Traffic forecasting is a research topic debated by several researchers affiliated to a range of disciplines. It is becoming increasingly important given the growth of motorized vehicles on the one hand, and the scarcity of lands for new transportation infrastructure on the other. Indeed, in the context of smart cities and with the uninterrupted increase of the number of vehicles, road congestion is taking up an important place in research. In this context, the ability to provide highly accurate traffic forecasts is of fundamental importance to manage traffic, especially in the context of smart cities. This work is in line with this perspective and aims to solve this problem. The proposed methodology plans to forecast day-by-day traffic stream using three different models: the Multilayer Perceptron of Artificial Neural Networks (ANN), the Seasonal Autoregressive Integrated Moving Average (SARIMA) and the Support Machine Regression (SMOreg). Using those three models, the forecast is realized based on a history of real traffic data recorded on a road section over 42 months. Besides, a recognized traffic manager in Morocco provides this dataset; the performance is then tested based on predefined criteria. From the experiment results, it is clear that the proposed ANN model achieves highest prediction accuracy with the lowest absolute relative error of 0.57%.

Simulation of the Daily Activity Plans of Travelers Using the Park-and-Ride System and Autonomous Vehicles: Work and Shopping Trip Purposes

The preferences of travelers determines the utility of daily activity plans. Decision-makers can affect the preference of travelers when they force private car users to use park-and-ride (P&R) facilities as a way of decreasing traffic in city centers. The P&R system has been shown to be effective in reducing uninterrupted increases in traffic congestion, especially in city centers. Therefore, the impacts of P&R on travel behavior and the daily activity plans of both worker and shopper travelers were studied in this paper. Moreover, autonomous vehicles (AVs) are a promising technology for the coming decade. A simulation of the AV as part of a multimodal system, when the P&R system was integrated in the daily activity plans, was carried out to determine the required AV fleet size needed to fulfill a certain demand and to study the impacts of AVs on the behavior of travelers (trip time and distance). Specifically, a group of travelers, who use private cars as their transport mode, was studied, and certain modifications to their daily activity plans, including P&R facilities and changing their transport mode, were introduced. Using the MATSim open-source tool, four scenarios were simulated based on the mentioned modifications. The four scenarios included (1) a simulation of the existing transport modes of the travelers, (2) a simulation of their daily activity plans when their transport modes were changed to AVs, (3) a simulation of the travelers, when P&R facilities were included in their activity chain plans, and (4) a simulation of their daily activity plans, when both P&R and AVs were included in their activity chain plans. The result showed that using the P&R system increased overall travel time, compared with using a private car. The results also demonstrated that using AVs as a replacement for conventional cars reduced travel time. In conclusion, the impact of P&R and AVs on the travel behavior of certain travelers was evaluated in this paper.

Has the prevalence of overweight, obesity and central obesity levelled off in the United States? Trends, patterns, disparities, and future projections for the obesity epidemic

Obesity (OB) is a serious epidemic in the United States. We examined OB patterns and time trends across socio-economic and geographic parameters and projected the future situation. Large national databases were used. Overweight (OW), OB and severe obesity (SOB) were defined using body mass index cut-points/percentiles; central obesity (CO), waist circumference cut-point in adults and waist:height ratio cutoff in youth. Various meta-regression analysis models were fit for projection analyses. OB prevalence had consistently risen since 1999 and considerable differences existed across groups and regions. Among adults, men's OB (33.7%) and OW (71.6%) levelled off in 2009-2012, resuming the increase to 38.0 and 74.7% in 2015-2016, respectively. Women showed an uninterrupted increase in OB/OW prevalence since 1999, reaching 41.5% (OB) and 68.9% (OW) in 2015-2016. SOB levelled off in 2013-2016 (men: 5.5-5.6%; women: 9.7-9.5%), after annual increases of 0.2% between 1999 and 2012. Non-Hispanic Blacks had the highest prevalence in women's OB/SOB and men's SOB. OB prevalence in boys rose continuously to 20.6% and SOB to 7.5% in 2015-2016, but not in girls. By 2030, most Americans will be OB/OW and nearly 50% of adults OB, whereas ∼33% of children aged 6-11 and ∼50% of adolescents aged 12-19 will be OB/OW. Since 1999, CO has risen steadily, and by 2030 is projected to reach 55.6% in men, 80.0% in women, 47.6% among girls and 38.9% among boys. Regional differences exist in adult OB prevalence (2011-2016) and across ethnicities; South (32.0%) and Midwest (31.4%) had the highest rates. US obesity prevalence has been rising, despite a temporary pause in 2009-2012. Wide disparities across groups and geographical regions persist. Effective, sustainable, culturally-tailored interventions are needed.

Structural Changes of the 21st Century and their Impact on the Gold Price

Beginning in the trough of 2000 and culminating in the peak of 2012, gold prices have exhibited a spectacular and unparalleled increase. Based on annual averages, the price of gold did not decrease at all over this 12 year period. The paper considers the various factors that have shaped the surge of gold spot prices over the last two decades using quarterly data. The analysis considers the role of structural changes such as China’s liberalization of the domestic gold market post-2003 and its impact on demand as well as other important economic factors such as risk, the role of quantitative easing and other fundamental factors in the gold market. The study investigates which of the macroeconomic and structural factors are responsible for the long term bullish trend in the gold price, of which China, global economic risk assessments along with quantitative easing have been crucial to understanding the almost uninterrupted price increase over the period.

Controls on late-Holocene drift-sand dynamics: The dominant role of human pressure in the Netherlands.

Holocene drift-sand activity in the northwest European sand belt is commonly directly linked to population pressure (agricultural activity) or to climate change (e.g. storminess). In the Pleistocene sand areas of the Netherlands, small-scale Holocene drift-sand activity began in the Mesolithic, whereas large-scale sand drifting started during the Middle Ages. This last phase not only coincides with the intensification of farming and demographic pressure but also is commonly associated with a colder climate and enhanced storminess. This raises the question to what extent drift-sand activity can be attributed to either human activities or natural forcing factors. In this study, we compare the spatial and temporal patterns of drift-sand occurrence for the four characteristic Pleistocene sand regions in the Netherlands for the period between 1000 BC and AD 1700. To this end, we compiled a new supra-regional overview of drift-sand activity based on age estimates (14C, optically stimulated luminescence (OSL), archaeological and historical ages). The occurrence of sand drifting was then compared in time and space with historical-route networks, relative vegetation openness and climate. Results indicate a constant but low drift-sand activity between 1000 BC and AD 1000, interrupted by a remarkable decrease in activity around the BC/AD transition. It is evident that human pressure on the landscape was most influential on initiating sand drifting: this is supported by more frequent occurrences close to routes and the uninterrupted increase of drift-sand activity from AD 900 onwards, a period of high population density and large-scale deforestation. Once triggered by human activities, this drift-sand development was probably further intensified several centuries later during the cold and stormier ‘Little Ice Age’ (LIA; AD 1570–1850).

The Sustainable Use of Outer Space: Complications and Legal Challenges to the Peaceful Uses and Benefit of Humankind

All over the world space applications are considered as vital tools for carrying development in respect of social, economic and environment. The major space faring country grows their economy, science, technology, security through the use of space. Predominantly, events for economic growth through space exploration have considered noteworthy in the international arena. An uninterrupted increase of space activities indicates that space law and policies have become significant for a large number of countries. However, increasing the space faring nations, commercialization by the public, private entities and privation of political willingness of influential countries also denote the new concern to the peaceful use of space, maintaining space safety, security and sustainability. The existing legal protection towards the peaceful and sustainable uses of space is not measured satisfactorily well-organized and competent. Particularly, the issue of commercialization of space is not well agreed. The goal of this paper is to examine the shortcomings of present regimes and legal challenges to the sustainable use of space with identifying that there is an urgent necessity for effective and more comprehensive regime not just at the international level, but also at the national level.

Trends and Weekly Cycles in a Large Swiss Emergency Centre: A 10 Year Period at the University Hospital of Bern.

Popular demand for high quality care has increased in recent years. This is also the case for medical services and support at all times of the day and night is nowadays required. During the last ten years, there has been a marked increase in the demands on hospital emergency hospitals, particularly in the Western industrialized countries. The present retrospective study investigates how the demands on a large Swiss university centre have changed over a period of 10 years. Patient numbers are differentiated by age, gender, nationality, weekday and mode of referral. A retrospective analysis was performed of the data of the patients admitted to the Emergency Centre of Bern University Medical Hospital (Inselspital) during the ten-year period from 2004 up to and including 2013 and who were treated as emergencies. A total of 264,272 patients were included in the study. It was shown that there was an uninterrupted annual increase from 23,555 patients in 2004 to 34,918 patients in 2013 (+48%). Most patients came to the Emergency Centre on Mondays, followed by Fridays. Because of the marked increase in life expectancy and the resulting demographic changes, there has been a marked increase in the number of older patients coming to the Emergency Centre for acute medical care. It was found that there were disproportionately high numbers of patients aged 20 to 49 years who were not Swiss citizens. In contrast, most patients over 60 were Swiss. In the coming years, emergency centres will have to adapt to the continued increase in patient numbers. This trend will continue, so that it is essential to consider the sociodemographic structure of a region when planning the availability of emergency medical care.

Life cycles and production of three predatory stonefly species (Plecoptera, Insecta) in the Kedrovaya River (Southern Primorskii Territory)

The life cycles and production of populations of the predatory stoneflies Skwala compacta, Stavsolus manchuricus, and Kamimuria exilis were studied in the Kedrovaya salmon stream (the Kedrovaya Pad Reserve, the south of Primorskii Territory). Skwala compacta and S. manchuricus are univoltine with direct embryonic development and slow nymphal growth during 311 and 294 days, respectively, including winter growth at low water temperatures. The life history of S. compacta was characterized by synchronous emergence and population recruitment, an uninterrupted increase in the nymphal body weight from May to September, rapid growth in October–November, and a sustained weight gain during the winter months until emergence in April–May. The life history of S. manchuricus was characterized by an extended period of emergence in May–July and recruitment from July to September, as well as by a wide range of size-age parameters, presumably related to the specificity of the reproductive system in adults and an external growth delay at early nymphal instars caused by high water temperatures in late summer and early autumn. Nymphs of S. manchuricus grew actively at 0.2°C during winter, which gave this species a competitive advantage over S. compacta and K. exilis whose growth was slow or absent in winter months. The semivoltine life cycle of K. exilis included a 9-month embryonic diapause and lasted about 4 years with periods of winter nymphal quiescence from December to February. Extended emergence and oviposition were recorded from the end of July to September. The population of K. exilis had a complex structure comprising 3 cohorts whose size ranges overlapped due to the extended flight period and recruitment of the new-generation nymphs in the spring of the next year. Nymphs of K. exilis grew fast during the warm period, when S. compacta and S. manchuricus were only appearing in the stream or underwent growth delay at relatively high water temperatures. The annual production of three species varied from 0.045 to 0.383 g/m2 dry mass, P/Bmean was 1.1–6.9; P/Bcoh = 6.2–9.1, and P/Byear = 4.1–9.4. Low values of P/Bmean and P/Byear were found in the semivoltine K. exilis, and high ones, in the univoltine S. compacta. The latter had a higher cohort-specific growth rate while its specific production was 0.026 day−1. The population of K. exilis had low values of the cohort-specific growth rate (0.013 day−1) and specific production (0.004 day−1). The highest production was observed in the population of S. manchuricus where nymphs grew at a specific rate of 0.023 day−1 while their mean density reached 59 ind./m2.

P-0167 - International Scientific Communications in the Field of Rectal Cancer Patient'S Quality of Life

P-0167 - International Scientific Communications in the Field of Rectal Cancer Patient'S Quality of Life

Diurnal variation in LH and temporal relationships between oscillations in LH and progesterone during the luteal phase in heifers

Diurnal variation in progesterone and LH during the luteal phase and the temporal relationships between oscillations of the two hormones were studied in 10 heifers by collection of blood samples at 0100, 0700, 1300, and 1900 h each day, beginning on Day 1 (Day 0 = ovulation). Concentration of LH on Days 5–9, but not on Days 10–14, was lower (P < 0.05) at 0700 h (0.25 ± 0.02 ng/mL) than at each of the other three hours (combined, 0.32 ± 0.02 ng/mL). An oscillation was defined as an uninterrupted increase and decrease in concentrations. The number of LH oscillations/heifer with the peak at 1900 h (6.1 ± 0.7) throughout the luteal phase was greater (P < 0.01) than for each of the other hours (combined, 4.0 ± 0.2). Diurnal variation in progesterone was not detected. Only statistically defined LH oscillations were used to determine the temporal association between the peak of an LH oscillation and various components of a progesterone oscillation. On Days 5–14, the frequency of the peak of an LH oscillation occurring at the same hour as the peak of a progesterone oscillation (26/48, 54%) was greater (P < 0.0001) than at the progesterone nadir (3/48, 6%). The frequency of the LH peak occurring during increasing (11/34, 32%) and decreasing (8/25, 32%) progesterone concentrations was intermediate (P < 0.05). Results indicated the following: 1) diurnal variation occurred in LH as determined by concentration and by the hour of the peak of an oscillation; and 2) LH oscillations were temporally and positively related to progesterone oscillations.

Three measures of longevity: Time trends and record values

This article examines the trend over time in the measures of "typical" longevity experienced by members of a population: life expectancy at birth, and the median and modal ages at death. The article also analyzes trends in record values observed for all three measures. The record life expectancy at birth increased from a level of 44 years in Sweden in 1840 to 82 years in Japan in 2005. The record median age at death shows increasing patterns similar to those observed in life expectancy at birth. However, the record modal age at death changes very little until the second half of the twentieth century: it moved from a plateau level, around age 80, to having a similar pace of increase as that observed for the mean and the median in most recent years. These findings explain the previously observed uninterrupted increase in the record life expectancy. The cause of this increase has changed over time from a dominance of child mortality reductions to a dominance of adult mortality reductions, which became evident by studying trends in the record modal age at death.

Prevalence of All Four Dengue Virus Serotypes Confirmed By Using Real Time RT-PCR among Population of Lahore Pakistan

Dengue fever is an emerging disease in Pakistan with uninterrupted increase in number of cases since 2006 Dengue fever epidemic in Lahore Pakistan. This study was planed to identify serotypes of dengue virus (DENV) involved in epidemic of 2008. The patients were screened in the microbiology laboratory with immunochromatographic kits then confirmed by antibody capture Enzyme linked immunosorbent assay (ELISA). Real Time Reverse Transcriptase-Polymerase Chain Reaction (Real Time RT-PCR) was performed by Real Time system to identify its serotype. Among analyzed 12 acute phase confirmed dengue patients, 50.74 % (n=7) were men and 49.26% (n=5) were women. Real Time Reverse Transcriptase-Polymerase Chain Reaction (Real Time RT-PCR) was performed by Real Time system to identify its serotype. Among analyzed 12 acute phase confirmed dengue patients, 58.33 % (n=7) were men and 41.66% (n=5) were women. On Real time RT-PCR, Dengue virus (DENV) was detected in 83.33 % (n=10) patients. Among them Serotype dengue-4 (DENV-4) was detected in 40% (n=4) patients, DENV-2 in 30% (n=3) patients, DENV-1 in 10% (n=1) and DENV-3 in 20% (n=2) patients. This reveals first time in Pakistan the presence of all four serotypes of dengue virus in Lahore, which desires vigilant monitoring by laboratory-based surveillance in order to foresee the nature of future epidemics.

Deep divers in shallow seas: Southern elephant seals on the Patagonian shelf

Elephant seals are wide-ranging, pelagic, deep-diving (average of 400–600 m) predators that typically travel to open waters and continental shelf edges thousands of kilometers from their land breeding colonies. We report a less common pattern of foraging in the shallow waters of a continental shelf. Southern elephant seals, Mirounga leonina, that breed at Península Valdés (Argentina), face an extended (∼1,000,000 km 2; 400–700 km-wide, depending on track), shallow (<150 m) and seasonally productive plateau, the Patagonian shelf. Adults of both sexes usually cross it in rapid transit to other potential foraging grounds on the shelf edge or in the Argentine Basin, but 2–4 year-old juveniles spread over the plateau and spent months in shallow waters. This behavior was recorded for 9 seals (5 males and 4 females) of 23 satellite-tracked juveniles (springs of 2004 and 2005) and for 2 subadult males studied in previous seasons. Trips included travel trajectories and time spent in areas where swim speed decreased, suggesting foraging. Preferred locations of juvenile females were in the proximity of the shelf break, where stratified waters had relatively high phytoplankton concentrations, but young and subadult males used the relatively cold (7–8 °C), low-salinity (∼33.3) mid-shelf waters, with depths of 105–120 m and a poorly stratified water column. Three of the latter seals, instrumented with time–depth recorders, showed dives compatible with benthic feeding and no diel pattern of depths distribution. Regions of the mid-shelf were used in different seasons and were associated with low chlorophyll- a concentration at the time of the visit, suggesting that surface productivity does not overlap with putative quality habitat for benthic foragers. Benthic diving on the shallow mid-shelf would be a resource partitioning strategy advantageous for young males prior to greater energetic demands of a high growth rate and a large body size. Later in life, the more predictable, bathymetry-forced, shelf-break front may offer the food resources that explain the uninterrupted increase of this population over several decades.

Adherence to Statin Therapy Under Drug Cost Sharing in Patients With and Without Acute Myocardial Infarction

As medication spending grows, Medicare Part D will need to adapt its coverage policies according to emerging evidence from a variety of insurance policies. We sought to evaluate the consequences of copayment and coinsurance policies on the initiation of statin therapy after acute myocardial infarction and adherence to therapy in statin initiators using a natural experiment of all British Columbia residents aged 66 years and older. Three consecutive cohorts that included all patients who began statin therapy during full drug coverage (2001), coverage with a $10 or $25 copay (2002), and coverage with a 25% coinsurance benefit (2003-2004) were followed up with linked healthcare utilization data (n=51,561). Follow-up of cohorts was 9 months after each policy change. Adherence to statin therapy was defined as > or = 80% of days covered. Relative to full-coverage policies, adherence to new statin therapy was significantly reduced, from 55.8% to 50.5%, under a fixed copayment policy (-5.4% points; 95% CI, -6.4% to -4.4%) and the subsequent coinsurance policy (-5.4% points; 95% CI, -6.3% to -4.4%). An uninterrupted increase in the proportion of patients initiating statin therapy after an acute myocardial infarction (1.7% points per quarter) was observed over the study period, similar to a Pennsylvania control population with full coverage. Sudden changes to full out-of-pocket spending, similar to Medicare's Part D "doughnut hole," almost doubled the risk of stopping statins (adjusted odds ratio, 1.94, 95% CI, 1.82 to 2.08). Fixed patient copayment and coinsurance policies have negative effects on adherence to statin lipid-lowering drug therapy but not on their initiation after myocardial infarction.

Exchange Rate Policy and Currency Substitution: The Case of Africa's Emerging Economies

This paper examines the dynamic of currency substitution (CS) in Egypt and South Africa. The study also assesses the causal relationships of this phenomenon. There are three main CS‐related differences between the two countries. These are (1) the orientation of economic policy, (2) the degree and level of CS, and (3) the trend of CS. During the study period 1991‐2001, Egypt used the exchange rate as an anchor to its economic programme. While in the case of South Africa, the authorities directly targeted inflation. During this period, CS in Egypt started at a substantial level and experienced a steady decline. Conversely, CS in South Africa started at an insignificant level, but observed an uninterrupted increase. The results suggest that the elasticity of CS, with respect to exchange rate, of South Africa is 2.3 times that of Egypt, and that the speed of adjustment in South Africa is 5 times faster than in Egypt. Granger‐causality tests indicate a unidirectional relationship from the exchange rate to CS, in both Egypt and South Africa. The test for the interest rate differential and CS indicate that causality runs from the former to the latter in South Africa, but it runs in the opposite direction in Egypt. The study suggests that despite the cost of the exchange rate anchoring policy, it is more suitable to a high CS environment. Inflation targeting policy can be effective in achieving its objective as long as the CS is insignificant.

Increasing incidence of testicular cancer--birth cohort effects.

The incidence of testicular cancer is rising in most Western populations. A collaborative study between nine population-based cancer registries in countries around the Baltic Sea was utilized in order to analyze in detail geographic variations and temporal trends in the occurrence of testicular cancer. There were 34,309 cases registered up until 1989 starting in Denmark in 1942 and most recently in Latvia in 1977. From the descriptive epidemiology it was obvious that there was a substantial variation in the age-standardized incidence amounting to about a 10-fold difference between the different countries ranging from 0.8 per 100,000 person-years in Lithuania to 7.6 per 100,000 person-years in Denmark. Previous studies have indicated that this increase is due to birth cohort effects. A more detailed analysis was therefore performed in those six countries with a sufficiently long period of cancer registration; Poland, former East Germany, Norway, Finland, Denmark and Sweden. This analysis showed that birth cohort is a more important determinant of testicular cancer risk than year of diagnosis. In Poland, former East Germany and Finland, there was an increasing risk for all birth cohorts. Among men born in Denmark, Norway or Sweden between 1930 and 1945, this increasing trend in risk was interrupted in these birth cohorts but followed thereafter by an uninterrupted increase by birth cohort. In conclusion, life time exposure to environmental factors which are associated with the incidence of testicular cancer appear to be more related to birth cohort than to year of diagnosis. Because testicular cancer typically occurs at an early age, major etiological factors therefore need to operate early in life, perhaps even in utero.

THE PHYSICAL MECHANISM OF PROMOTED AMORPHOUS CRYSTALLIZATION BY MULTIPLE ULTRASHORT ELECTROPULSING

Amorphous Fe78Si9B13 specimens have been treated by multiple ultrashort electropulsing with a high current density. The treatment conditions were：1.Keeping the pulse frequency and acting time constant, the current density uninterrupted increases. 2.The pulse frequency increases continuously under constant current density and acting time. The crystallized structures of specimens after electropulsing were investigated by Mssbauer spectroscopy. The results show that the nucleation rate of base metal phase in amorphous specimens increases obviously with the increase of current density and pulse frequency.

Increase in testicular cancer incidence in six European countries: a birth cohort phenomenon.

For unknown reasons, the age-standardized incidence of testicular cancer has shown a rapid increase in virtually all countries (mostly Western) studied. For populations with a sufficiently long period of cancer registration, this development can be traced back to the first half of this century. By evaluating data from six countries with long periods of cancer registration (Denmark, Norway, Sweden, the former German Democratic Republic [East Germany], Finland, and Poland), we sought to determine whether the increase in testicular cancer risk follows a birth cohort pattern and, if so, to quantify and compare any birth cohort effects. A total of 30,908 incident cases of testicular cancer, diagnosed from 1945 through 1989 in men who were 20-84 years of age, were identified in population-based cancer registries in the six countries. In addition to performing simple trend analyses, we fitted several Poisson regression models (with the explanatory variables age, time period [calendar time], and birth cohort) to the data. Individual models were estimated by the maximum likelihood method. The age-standardized incidence of testicular cancer was found to vary among the six populations and, on the basis of total registration data, increased annually at rates ranging from 2.3% (in Sweden) to 5.2% (in East Germany). A comparison of several regression models indicated that birth cohort was a stronger determinant of testicular cancer risk than was calendar time for all six populations. Within each population, little variation in testicular cancer risk was observed for men born between 1880 and 1920; thereafter, the risk began to increase. Among men born in Denmark, Norway, and Sweden between 1930 and 1945 (the period encompassing the Second World War), the increasing trend in risk was interrupted (i.e., a leveling in risk occurred). After 1945, an uninterrupted increase in risk was observed for all six populations. With men born around 1905 as the reference group, the relative risk of testicular cancer for those born around 1965 varied from 3.9 (95% confidence interval [CI] = 2.7-5.6) in Sweden to 11.4 (95% CI = 8.3-15.5) in East Germany. The increasing trend in testicular cancer risk observed for these six populations follows a birth cohort pattern. This distinct risk pattern provides a framework for the identification of specific etiologic factors.

Potential defect in the vascular control of nonshivering thermogenesis in the obese Zucker rat hind limb

Vascular control of nonshivering thermogenesis in the perfused hind limb of obese and lean Zucker rats were compared using two vasoconstrictors, norepinephrine and serotonin. For hind limbs of both phenotypes, norepinephrine infusions resulted in a dose-dependent uninterrupted increase in perfusion pressure and a biphasic change in oxygen uptake (VO2), characterized by a stimulation at low concentrations, and an increasing inhibition at higher concentrations that gradually overcame the stimulation in a dose-dependent manner. At concentrations of norepinephrine greater than 1 microM, the inhibitory effect predominated and gave rise to values for VO2 less than basal. The obese hind limb had a lower basal VO2 and a lower maximal VO2 mediated by norepinephrine than the lean rat, but these differences appeared to relate largely to the lower muscle mass and higher content of fat of the obese hind limb. Serotonin infusions resulted in dose-dependent increase in perfusion pressure and an accompanying decrease in VO2. Pressure changes were identical for the obese and lean hind limbs, but the decrease in VO2 due to serotonin was greater in the hind limbs from the lean rats, and this difference remained when the data were expressed in terms of muscle mass perfused. It is concluded that the relatively lower content of muscle of the obese hind limb accounts for its lower basal and lower maximal norepinephrine-mediated thermogenesis. In addition, an intrinsic defect in obese hind limb muscle response to serotonin is present, which may be indicative of a decrease in the potential for vasoconstrictor-regulated thermogenesis that could have implications for whole-body energy balance by the obese phenotype.