Is respirometry a standardized technique? A review of measurement of avian resting metabolic rates

A plethora of studies have been conducted since the 1920s on avian thermoregulatory physiology variables as measured using respirometry. In particular, many of these studies have determined basal metabolic rate in a wide array of avian taxa. Start time of experiment, duration of experiment, length and number of measurements to determine the resting metabolic rate at a particular temperature (RMR_Ta) were reviewed in avian metabolic studies prior to 2011. Although respirometry is considered a standard technique, it was evident that in avian studies there is a continuum of duration time used for measurements with a number of studies (30%) using only 1–2 h data collection while at the other end of the continuum a number of studies (22%) have used 9–15 h data collection (and some longer). Many studies are unclear in how many hours were used (22%) to collect data. We found that most avian studies (94%) were on postabsorptive birds and most were during the birds' rest phase (69.5%). The majority (62.6%) of studies only measured metabolic rate at one temperature per trial, while others (19.2%) have measured RMR_Ta at various temperatures within a single trial period. Recently, several studies have shown that for diurnal birds measurements need to be conducted during the scotophase, for the duration of the night (>9 h; except at extreme temperatures where evaporative water loss is high and may result in mortalities), and at one experimental temperature per night if reliable and precise data are to be obtained. In addition, repeated measures need to be stable for at least an hour to be considered as RMR_Ta. Consequently, given the variance in methods used in prior avian metabolic studies cognizance of this is required when designing and implementing avian thermoregulatory physiological measurements using respirometry, particularly if data are later used for comparative allometric studies.     

Human activities and nitrogen in waters

Shenzhen was a famous typical rapid-urbanization city in China, and this study compares plant species diversity in urban parks from the start of urbanization through 2011. Results show that the plant species biodiversity increased rapidly: the rate changed from 140% to 980% and the average increasing rate was 406.90%, but only 12.59% of plants spread into the park naturally. Shrubs had the highest rate; with change increasing from 20.70% to 43.54%, they replaced trees to become the dominant type. The biodiversity of native plants also increased, but their proportion relative to all species had declined. The homogenization of plant species in the parks increased; more than half of the plant species (62.24%) are located in 5–7 parks at once now, compared with 65.52% of species located in only 2–3 parks at the start of the study. The increase of species was faster than the increase of families; many new species planted belong to a few specific families. The ratio of species to families declined from 0.40 to 0.32. Results indicate that the rapid increase of plant species diversity as well as their homogenization happened in the initial stage of urbanization, and so rapid urbanization might be the major factor in the changes in plant species diversity in municipal parks. Rapid urbanization was an important cause of change in plant species diversity.     

Estimating average annual percent change for disease rates without assuming constant change

The annual percent change (APC) is often used to measure trends in disease and mortality rates, and a common estimator of this parameter uses a linear model on the log of the age-standardized rates. Under the assumption of linearity on the log scale, which is equivalent to a constant change assumption, APC can be equivalently defined in three ways as transformations of either (1) the slope of the line that runs through the log of each rate, (2) the ratio of the last rate to the first rate in the series, or (3) the geometric mean of the proportional changes in the rates over the series. When the constant change assumption fails then the first definition cannot be applied as is, while the second and third definitions unambiguously define the same parameter regardless of whether the assumption holds. We call this parameter the percent change annualized (PCA) and propose two new estimators of it. The first, the two-point estimator, uses only the first and last rates, assuming nothing about the rates in between. This estimator requires fewer assumptions and is asymptotically unbiased as the size of the population gets large, but has more variability since it uses no information from the middle rates. The second estimator is an adaptive one and equals the linear model estimator with a high probability when the rates are not significantly different from linear on the log scale, but includes fewer points if there are significant departures from that linearity. For the two-point estimator we can use confidence intervals previously developed for ratios of directly standardized rates. For the adaptive estimator, we show through simulation that the bootstrap confidence intervals give appropriate coverage.     

日本生物产业发展现状与趋势分析

日本在生物技术领域居世界前列,生物产业是日本的重点产业,政府通过优化发展战略、完善相关机构、加大资金投入、促进官产学结合等方式加速发展生物技术与产业。综述了日本生物产业发展现状,结合日本的国情和优势,对其未来生物产业的发展方向和重点进行了分析,以期对我国生物技术产业的发展起到借鉴作用。     

Understanding recent trends in childhood obesity in the United States

The prevalence of childhood obesity in the United States has more than tripled over the last four decades from 5 percent in 1978 to 18.5 percent in 2016. There is evidence for a break in trend in recent years: after growing from 0.4 to 0.7 percentage point per year between 1978 and 2004, the rate of increase has slowed to 0.1 percentage point per year from 2004 to 2016. To better understand these trends, in this paper we analyze a range of datasets that collect information on childhood obesity. We analyze the data overall, across the age distribution, across birth cohorts, and for subgroups of interest. We find steady increases in cohort-level obesity prevalence through approximately age 10, with levels unchanged thereafter, suggesting a need for additional interventions at early ages. We find that the prevalence of obesity has diverged by race and gender in recent years, especially among children entering kindergarten. Compared with 5-year-olds in 1997, 5-year-olds in 2010 were 2 percentage points more likely to be obese overall. Black and Hispanic 5-year-olds were 5 and 3 percentage points more likely to be obese, respectively, while whites had a 1 percentage point increase in obesity. However, overall and among all subgroups the rate of growth in obesity from kindergarten through 3rd grade has declined in recent years. Together, these findings can inform a future research literature that aims to target obesity interventions where they will be most impactful.     

Mute swan (Cygnus olor) winter distribution and numerical trends over a 16-year period (1987/1988–2002/2003) in France

The numbers of mute swans (Cygnus olor) at 98 wetland locations in France were monitored monthly during the winter (December–February) for 16 years by a national network of observers as part of a broader national wildfowl monitoring scheme. Log-linear Poisson regressions with TRIM software were used to estimate missing counts and produce national numbers and indices. These corrected indices were in turn used to calculate an average annual rate of change and the associated confidence interval that subsequently enabled the computation of a cumulated (global) rate of change and associated confidence interval. The latter were interpreted to classify the numerical trends over the whole period. For the six wetlands with the largest numbers of mute swans, average numbers of swans were also compared between wetlands and months. General Linear Models were then used to test simultaneously for (1) differences between years and between wetlands for each month and (2) between years and between months separately for each of the six wetlands. The mute swan average annual rate of change was >7% for each month. The global rate of variation corresponded to a “strong increase” after TRIM analyses. This result strongly supports the necessity of maintaining both national and international monitoring schemes in order to be able to quickly detect major increases in swan numbers at specific sites, particularly where increasing numbers may result in a conflict with farmers or in inter-specific competition with other waterbirds and/or represent a possible sanitary/public health hazard due to the potential for swans to carry avian influenza viruses.     

Long term records of riverine dissolved organic matter

This presents the longest, consistent records of dissolved organic carbon in rivers ever published. This study presents long-term records of organic matter as indicated by water colour that were constructed for three catchments in Northern England for as far back as 1962. Observations show that there have been large increases in DOC concentrations over the period of study with in one case a doubling of the concentration over a period of 29 years. However, in one of the catchments no significant change was observed over a 31-year period. All catchments show common inter-annual control on carbon release in response to droughts, but no step increases in DOC concentrations were observed in response to such perturbations with pre-drought levels being restored within a period 3–4 years. Observed increasing trends do not correlate with changes in river discharge, pH, alkalinity or rainfall, but do coincide with increasing average summer temperatures in the region. The times series of DOC concentration over the period of the record appears stationary, but the distribution of daily values suggests a change in sources of colour over the increasing trend. The evidence supports a view that increases in carbon release are in equilibrium with temperature increases accentuated by land-use factors.     

On the Use of Two-stage Cluster Samples in Epidemiological Population Studies

This paper discusses the need to account for the sampling scheme in an analysis of epidemiological population data which were collected by a two-stage cluster sample. An example is presented where for validity reasons one should generally account for the sampling scheme, though a rule-of-thumb is given to estimate the effect of not doing so. The example concerns one of the centers (Augsburg, F. R. G.) participating in the WHO MONICA Project, which was designed to study the relationship between changes in risk factor levels, as measured by several surveys in each center, and changes in cardiovascular incidence rates, as measured by a registry system for each center. Variance estimation methods which either account for or ignore the sampling scheme are compared for a particular sampling scheme. Easily computable upper bounds on the effect on variances of ignoring the sampling scheme are presented, both over all possible variables, and for a particular variable.     

Phytophenological trends in Switzerland

Nation-wide phenological observations have been made in Switzerland since 1951. In addition to these observation programmes, there are two very long phenological series in Switzerland: leaf bud burst of horse-chestnut trees has been observed in Geneva since 1808 and full flowering of cherry trees in Liestal since 1894. In addition to the presentation of these two long phenological series, trends for 896 phenological time series have been calculated with national data from 1951 to 1998. The earlier bud burst of horse-chestnut trees in Geneva can be attributed mainly to the city effect (warmth island). This phenomenon was not observed with the cherry tree flowering in Liestal. A clear trend towards earlier appearance dates in spring and a weak tendency towards later appearance dates in autumn could be shown with data from the national observation network. It must be noted that different phenophases and plant species react differently to various environmental influences. Received: 25 October 2000 / Revised: 9 May 2001 / Accepted: 4 June 2001