Spatial and temporal patterns of non-colonial boring organisms (polychaetes,sipunculans and bivalve molluscs) in Porites at Lizard Island,Great Barrier Reef

A study of the spatial and temporal patterns of colonisation by non-colonial boring organisms to dead Porites coral substrate was conducted at Lizard Island, Great Barrier Reef over a 4 year period. These fluctuations were analysed for each group of borers, and most exhibited strong site preferences, with preferred sites being on the windward slope in 10 m and on the reef flat in 1 m. A lagoonal patch reef site exhibited consistently low colonisation. Most groups showed inter-year variations in colonisation with spring/early summer dominating. These variations are discussed in terms of what is known about their life histories. These results together with those of Kiene (in preparation) which document varying rates of bioerosion, at these sites over the same time period, demonstrate that variations in borer colonisation are responsible for the variations in rates of bioerosion calculated. Thus rates of bioerosion by borers will vary significantly between different reef environments.     

Explaining variations in cesarean section rates: patients,facilities or policies?

Using overall rates of cesarean section and either rates of diagnosis or rates of cesarean section for the four main indications for this procedure, we analysed the variations among teaching and community hospitals in four of Ontario''s six regions. The rates varied substantially in both 1979 and 1982, with the overall rate for cesarean section in 1982 being 17.1 to 21.0 per 100 deliveries in the teaching hospitals and 16.5 to 19.7 in the community hospitals. The rate of diagnosis of dystocia varied up to threefold in the teaching hospitals and up to twofold in the community hospitals. Fetal distress was diagnosed at even more variables rates. The rate of repeat cesarean section varied most in the teaching hospitals, whereas the rate of cesarean section for breech presentation varied significantly in the community and the teaching hospitals in 1982 but only in the community hospitals in 1979. Nearly all the rates increased between 1979 and 1982. Differences in patient characteristics and in availability of resources appeared less important in explaining these rate variations than differences in clinical policy.     

Influences of body mass,temperature, oxygen tension,and salinity on respiratory oxygen consumption of cyprinodontoid fishes of three families

This review evaluates the current state of knowledge of influences of body mass, ambient temperature, P_O2, and salinity on routine metabolic rates of members of three families, Fundulidae, Cyprinodontidae, and Poeciliidae, belonging to the order Cyprinodontiformes. The study was motivated by Winberg’s (Fisheries Research Board of Canada, Translation Series No. 194. Distributed by the Fisheries Research Board of Canada Biological Station, Nanaimo, BC, 1960) conclusion that the Cyprinodontiformes (Winberg included only live-bearing poeciliids) generally have lower metabolic rates that do other fishes. Based on available information Winberg’s conclusion was borne out that live-bearing freshwater poeciliids show lower than average routine metabolic rates compared to other freshwater fish groups. This is also true of poeciliids from saline waters, and of both freshwater and saline-water members of the related families Fundulidae and Cyprinodontidae. However, considerable variation in metabolic patterns was noted within and among these three families. There were geographic variations between subspecies of some species. Some island groups/species showed lower routine metabolic rates than did allied mainland groups/species. Thermal responses (Q₁₀ values) in routine metabolic rates of these fishes showed variations with geographic location, P_O2, salinity and size. Values of P_O2crit were altered among species by temperature, body size/age, and possibly salinity. Influences of ambient salinity on routine metabolic rates of these cyprinodontoid fishes also showed variations with temperature and size/age of individuals. The patterns of metabolic responses in these cyprinodontoid fishes to environmental conditions were generally similar to those of other species. Unfortunately, the available information on these fishes lacks the uniformity that would allow for critical and quantitative comparisons between and among the cyprinodontoids and with other species.     

The relative importance to population increase of fluctuations in mortality,fecundity and the time variables of the reproductive schedule

Summary Previous authors have used simple models to investigate the relative importance to population increase of variations in the total and age-specific reproductive rates. But while acknowledging that the latter were the product of the age specific birth and death rates, they have used their models only to investigate changes in total or age-specific birth rates and have not been concerned with variations in death rates. This paper extends the use of Lewontin's (1965) model, to a wide range of values of r, the exponential rate of population increase. It shows how the relative importance of changes in certain life-history features can change with r and be reversed when r is near to zero. It is also shown that variations in mortality rate are not necessarily best expressed in analogous terms to variations in birth rate. If more suitable terms are used it is seen that changes in mortality rate can be of varying importance depending on the existing mortality rate. They can be overwhelmingly important when the mortality rate is high.     

Regional variations in the use of home care services in Ontario, 1993/95

BACKGROUND: Although regional variations in the use of many health care services have been reported, little attention has been devoted to home care practices. Given the dramatic shift in care settings from hospitals to private homes, it is important to determine the extent to which home care practices vary by geographic region. METHODS: Data from the Canadian Institute for Health Information and the Ontario Home Care Administration System database were used to assess regional variations in rates of home care use following inpatient care and same-day surgery for the fiscal years 1993, 1994 and 1995. Various measures of regional variation were employed. RESULTS: Of the 2,870,695 inpatient separations and 1,803,307 same-day surgery separations during the study period, 359,972 and 64,541, respectively, were followed by home care. The rate of home care use per 100 separations was 12.5 for inpatients and 3.6 for same-day surgery patients. There was a a 3.5-fold regional variation in the rates of home care use following inpatient care and a 7-fold variation in rates of use following same-day surgery. Additional home care funding to attain calculated target rates was estimated to be $48.9 million (30% of expenditures for patients recently discharged from hospital over the study period). For a 20% increase in service provision it was estimated that an additional injection of $42.2 million is required. INTERPRETATION: The wide regional variations in rates of home care use highlight the importance of modifying home care funding to ensure that all residents of Ontario have equal access to services. To achieve this our estimates suggest that a substantial increase in home care funding is warranted.     

Variability in asthma: symptom perception, care, and outcomes

Asthma remains a global respiratory health concern. Substantial variations in asthma outcomes persist in Canada despite the dissemination of national management guidelines. Many factors and their interactions presumably contribute to variations in outcomes, including asthma prevalence, severity, symptom recognition, self-management behaviour, access to care, and management. This article reviews the physiology of symptom perception in asthma, specifically the role of dynamic lung hyperinflation (DH) on the perception of the intensity and quality of dyspnea in asthma, and the link between blunted perception and life-threatening asthma. Additionally, the magnitude and correlates of regional variation in emergency department visit rates and hospitalizations for asthma in Ontario are reviewed.     

Fertility and child spacing among the urban Poor in a Third World city: The case of Calcutta,India

Studies of fertility behavior in the Third World have relied heavily on two variables, income and education, to explain variations in fertility rates. If the socio-economic variables traditionally employed to account for variations in fertility rates are invariant, what other factors could influence fertility rates and child spacing? On the basis of data from 180 slum households in Calcutta, India, the paper indicates that in a situation where material and social conditions are comparable, cultural and demographic variables play a major role in influencing reproductive behavior. In this case study, caste and family type are shown to have a significant effect on the numbers of surviving children. As regards child spacing, the woman's age is of paramount importance.     

Trends and Variations in the Rates of Hospital Complications,Failure-to-Rescue and 30-Day Mortality in Surgical Patients in New South Wales,Australia, 2002-2009

Background

Despite the increased acceptance of failure-to-rescue (FTR) as an important patient safety indicator (defined as the percentage of deaths among surgical patients with treatable complications), there has not been any large epidemiological study reporting FTR in an Australian setting nor any evaluation on its suitability as a performance indicator.

Methods

We conducted a population-based study on elective surgical patients from 82 public acute hospitals in New South Wales, Australia between 2002 and 2009, exploring the trends and variations in rates of hospital complications, FTR and 30-day mortality. We used Poisson regression models to derive relative risk ratios (RRs) after adjusting for a range of patient and hospital characteristics.

Results

The average rates of complications, FTR and 30-day mortality were 13.8 per 1000 admissions, 14.1% and 6.1 per 1000 admission, respectively. The rates of complications and 30-day mortality were stable throughout the study period however there was a significant decrease in FTR rate after 2006, coinciding with the establishment of national and state-level peak patient safety agencies. There were marked variations in the three rates within the top 20% of hospitals (best) and bottom 20% of hospitals (worst) for each of the four peer-hospital groups. The group comprising the largest volume hospitals (principal referral/teaching hospitals) had a significantly higher rate of FTR in comparison to the other three groups of smaller-sized peer hospital groups (RR = 0.78, 0.57, and 0.61, respectively). Adjusted rates of complications, FTR and 30-day mortality varied widely for individual surgical procedures between the best and worst quintile hospitals within the principal referral hospital group.

Conclusions

The decrease in FTR rate over the study period appears to be associated with a wide range of patient safety programs. The marked variations in the three rates between- and within- peer hospital groups highlight the potential for further quality improvement intervention opportunities.     

Seasonal variations in the energetics of an Australian nectarivorous bird, Lichmera indistincta

1. Seasonal variations in unit perching costs, flying costs and energy budgets for Lichmera indistincta were investigated. 2. Unit perching and flying costs were greatest in winter and least in summer. Variations in perching costs occurred principally because of changes in conductance. Flying cost variations may have been due to changes in wing disc loading and/or the integrity of wing feathers. 3. Rates of net energy intake were greatest in winter and least in summer. Variations in these rates were such that they offset changes in the rates of total energy expenditure to provide diurnal energy balance. 4. Regardless of the season, net daytime energy storage proceeded at a uniform rate and resulted in the storage of sufficient energy to offset overnight expenditure.     

Metabolism of the Fe, Cu, Zn, Mg, MN and Co in the ovum of Cancer irroratus (decapod crustacean)]

The concentrations of Fe, Cu, Zn, Mn and Co in the eggs of Cancer irroratus show variations in relation with time running out after laying, that is to say with embryogenesis. The increase of the rates of Fe, Mn and Mg is independant of the variations of the water content. Inversely, the decrease of Cu and Zn concentrations is in close relation with the increase of water content during the same period. The increase of Fe, Mn and Mg concentrations seems to be essentially under the dependance of physico-chemical, rather than biochemical, process in connection with the chitinous nature of the membranes surrounding the egg.     

Equity and the NHS: self-reported morbidity,access, and primary care.

The patterns of access to primary health care for 27 154 people were examined, using the raw data of the 1974 General Household Survey about self-reported morbidity and use of services. Access rates were calculated for four categories of health: the not ill, the acutely sick, the chronically sick without restricted activity, and the chronically sick with restricted activity. Contrary to the conclusions of existing publications, the analysis shows that the NHS has achieved equity in terms of access to primary health care: there is no consistent bias against the lower socioeconomic groups and, in the case of some health care categories, these have proportionately higher rates of access than their rates of self-reported morbidity would indicate. The findings also show large variations in patterns of access both between and within these categories of health.     

Modeling multiphase fluid flow,mass transfer,and chemical reactions in bioreactors using large-eddy simulation

We present a transient large eddy simulation (LES) modeling approach for simulating the interlinked physics describing free surface hydrodynamics, multiphase mixing, reaction kinetics, and mass transport in bioreactor systems. Presented case-studies include non-reacting and reacting bioreactor systems, modeled through the inclusion of uniform reaction rates and more complex biochemical reactions described using Contois type kinetics. It is shown that the presence of reactions can result in a non-uniform spatially varying species concentration field, the magnitude and extent of which is directly related to the reaction rates and the underlying variations in the local volumetric mass transfer coefficient.     

Seasonality of reproduction and production in farm fishes, birds and mammals

A very large majority of farm animals express seasonal variations in their production traits, thus inducing seasonal availability of fresh derived animal products (meat, milk, cheese and eggs). This pattern is in part the consequence of the farmer's objective to market his products in the most economically favourable period. It may also be imposed by the season-dependent access to feed resources, as in ruminants, or by the specific requirements derived from adaptation to environmental conditions such as water temperature in fish. But seasonal variations in animal products are also the consequence of constraints resulting from the occurrence of a more or less marked seasonal reproductive season in most farm animal species including fish, poultry and mammals. Like their wild counterparts, at mid and high latitudes, most farm animals normally give birth at the end of winter-early spring, the most favourable period for the progeny to survive and thus promote the next generation. As a consequence, most species show seasonal variations in their ovulation frequency (mammals and fish: presence or absence of ovulation; birds: variations or suppression of laying rates), spermatogenic activity (from moderate to complete absence of sperm production), gamete quality (variations in fertilisation rates and embryo survival), and also sexual behaviour. Among species of interest for animal production, fishes and birds are generally considered as more directly sensitive to external factors (mainly temperature in fish, photoperiod in birds). In all species, it is therefore advisable that artificial photoperiodic treatments consisting of extra-light during natural short days (in chickens, turkeys, guinea fowl, sheep and goats) or melatonin during long days (in goats, sheep) be extensively used to either adjust the breeding season to animal producer needs and/or to completely overcome seasonal variations of sperm production in artificial insemination centres (mammals) and breeder flock operations (poultry, fish farming). Pure light treatments (without melatonin), especially when applied in open barns, could be considered as non invasive ones which fully respect animal welfare.     

Trends in regional cancer mortality in Taiwan 1992–2014

BackgroundAlthough the cancer mortality rate in Taiwan has been declining in recent years, no study has yet reported any regional differences in cancer mortality rates in Taiwan. We hypothesized that regional cancer mortality rates in Taiwan, an ethnically homogeneous society, exhibited no significant variations.MethodsWe investigated the trends in Taiwan regional cancer mortality between 1992 and 2014. We analyzed regional age-standardized cancer mortality rates for lung, liver, colon, stomach, oral, breast, and prostate cancers using the Taiwan Longitudinal Health Insurance Database and Demographic Database. Furthermore, we applied Joinpoint regression analysis to evaluate the trends across different regions.ResultsThere are clear regional variations in mortality rates for liver, stomach, and oral cancers, but not for lung, colon, breast, and prostate cancers. The regional death rates of oral cancer, especially for eastern Taiwan, not only elevate the fastest (APC = 14.78% per year, P < 0.001) but also show the largest disparities between men and women. Regional death rates for stomach cancer, which declined most rapidly, are converging in both general and gender groups. Liver cancer is the only one with regional variations whose trends do not all go in the same direction. We also demonstrated that northern Taiwan has significant regional advantages with respect to cancer mortality.ConclusionsSome but not all cancers in Taiwan show regional disparities. Liver, stomach, and oral cancers in Taiwan exhibit clear regional variations in mortality rates. In particular, the regional variations in oral cancer mortality rates are consistent with those in alcohol consumption.     

Life-history variations in the fluvial sculpin, Cottus nozawae (Cottidae), along the course of a small mountain stream

Life-history variations in male and female fluvial sculpins, Cottus nozawae, were studied in a small mountain stream in Hokkaido, Japan, primarily by using capture-mark-recapture methods. At three study areas established along the stream course, the majority of marked sculpins were recaptured in their original location over one or more years, indicating their long-term occupation of each restricted habitat area. Sculpin densities increased toward the upstream habitats, whereas individual growth rates were more rapid downstream. In both sexes, sculpins distributed downstream matured at a larger body size and later in life than upstream sculpins, clearly demonstrating a clinal variation in these respects. A comparison of life-history variations in C. nozawae with those in amphidromous C. hangiongensis suggests that intrapopulational life-history variations in the former might be environmentally induced, and that one of the most important determinants for the variations in Cottus species might be population density.     

Copepod egg production, moulting and growth rates, and secondary production, in the Skagerrak in August 1988

Measurements of hydrography, chlorophyll, moulting rates ofjuvenile copepods and egg production rates of adult female copepodswere made at eight stations along a transect across the Skagerrak.The goals of the study were to determine (i) if there were correlationsbetween spatial variations in hydrography, phytoplankton andcopepod production rates, (ii) if copepod egg production rateswere correlated with juvenile growth rates, and (iii) if therewas evidence of food-niche separation among co-occumng femalecopepods The 200 km wide Skagerrak had a stratified water columnin the center and a mixed water column along the margins. Suchspatial variations should lead to a dominance of small phytoplanktoncells in the center and large cells along the margins; however,during our study blooms of Gyrodinium aureolum and Ceratium(three species) masked any locally driven differences in cellsize: 50% of chla was >11 µm, 5% in the 11–50µm fraction and 45% <50 µm. averaged for allstations. Chlorophyll ranged from 0.2 to 2.5 µg l^–1at most depths and stations. Specific growth rates of copepodsaveraged 0.10 day^–1 for adult females and 0.27 day^–1for juveniles The latter is similar to maximum rates known fromlaboratory studies, thus were probably not food-limited. Eggproduction rates were food-limited with the degree of limitationvarying among species: 75% of maximum for Centropages typicus, 50% for Calanus finmarchicus, 30% for Paracalanus parvus and 15% for Acartia longiremis and Temora longicornis. Thedegree of limitation was unrelated to female body size suggestingfood-niche separation among adults. Copepod production, summedover all species, ranged from 3 to 8 mg carbon m^–3day^–1and averaged 4.6 mg carbon m^–1 day^–1. Egg productionaccounted for 25% of the total.     

Longitudinal structure, density and production rates of a neotropical stream fish assemblage: the river Ubatiba in the Serra do Mar, southeast Brazil

Spatio-temporal variations in the structure, density, biomass and production rates of fish were assessed in the neotropical River Ubatiba (Serra do Mar, southeast Brazil). Electrofishing techniques and the length-frequency method were shown to be reliable for the assessment of (ish numbers and production rates in these running waters of medium conductivity. Eighteen fish species of small size and prolonged spawning period were broadly distributed throughout the river catchment. Over the year, the assemblage structure was persistent along the river. Water column omnivore and algae/detritivore species dominated in density (15086-70330 ind. ha⁻¹), whereas three omnivores and a piscivorous species accounted for 70% of the production (51.5-250.4 kg ha⁻¹ yr⁻¹). Comparison of production rates among, tropical, temperate and Mediterranean stream fish assemblages indicate lower rates in tropical streams and an inverse relationship between production and species diversity, lower production rates in high-diversity tropical streams vs higher rates in low-diversity Mediterranean streams, with intermediate rates in temperate streams of intermediate diversity.     

Peer review, program officers and science funding

Increased competition for research funding has led to growth in proposal submissions and lower funding-success rates. An agent-based model of the funding cycle, accounting for variations in program officer and reviewer behaviors, for a range of funding rates, is used to assess the efficiency of different proposal-submission strategies. Program officers who use more reviewers and require consensus can improve the chances of scientists submitting fewer proposals. Selfish or negligent reviewers reduce the effectiveness of submitting more proposals, but have less influence as available funding declines. Policies designed to decrease proposal submissions reduce reviewer workload, but can lower the quality of funded proposals. When available funding falls below 10-15% in this model, the most effective strategy for scientists to maintain funding is to submit many proposals.     

Postglacial range expansion and population growth of Picea mariana, Picea glauca and Pinus banksiana in the western interior of Canada

The fossil pollen records from the sediments of thirteen lakes are used to reconstruct the postglacial spread and population expansions of Picea mariana (Mill.) B.S.P., Picea glauca (Moench) Voss and Pinus banksiana Lamb. across the western interior of Canada. The objective of this study was to examine temporal and spatial patterns in the growth of the populations and to determine if intraspecific and interspecific variations exist across a range of latitudes and elevations. Pollen accumulation rates (PARs) are estimated from pollen grain counts and sedimentation rates throughout the early to mid-Holocene and are used to represent the population level at the time of pollen deposition. Exponential equations are used to calculate population growth rates. Three-dimensional diagrams (time, space, abundance) are constructed to illustrate range expansion and population growth.The rates of population growth varied from south to north for all three species. Pinus banksiana , on average, had slower population growth rates, and its expansion across the region began over 4000 years later and lasted approximately 1000 years longer than the two Picea species. All three tree taxa experienced reduced rates of population growth at northern high elevation sites. These variations are examined in light of the physical and biological environmental conditions which existed during postglacial range expansion and population growth.     

Dynamics of a stable, large volume, laboratory ecosystem containing Daphnia and phytoplankton

Daphnia magna and phytoplankton were maintained in stable, large-volume(3400 l), indoor, planktonic model ecosystems for up to 20 weeks.Ecosystem stability was demonstrated by damped oscillationsin population abundance, and by a return to steady-state conditionsif the system was perturbed. The steady-state biomass of daphniaand algae responded to variations in nutrient loading ratesand daphnia harvesting rates in accordance with predictionsfrom a mathematical model. Increased nutrient addition resultedin an increase in biomass of daphnia, but not phytoplankton,if both were present. Increased harvesting caused an increasein chlorophyll and decreased daphnia biomass. Phosphorus additionswere balanced by sedimentation losses which were proportionalto daphnia biomass. Increased harvesting rates resulted in decreasedphosphorus loss rates and increased efficiency of phosphorusconversion into harvested daphnia. Damped oscillations had aperiodicity of 3.5 weeks and could be successfully modelledassuming a half-saturation constant for phosphorus control ofalgal growth of 1 µg l^–1. The ecosystem became unstableif nutrient loading rates exceeded a defined limit which wasa function of harvesting rates. Steady-state chlorophyll anddaphnia biomass levels were similar to levels approached inLake Michigan in summer in 1983 and 1984, when the zooplanktonbiomass was dominated by Daphnia pulicaria.