Seasonal pattern in the rate of growth in height of children living in Guatemala.

Monthly increments of height for a sample of 164 Guatemala City school children are analyzed for the presence of a seasonal pattern in rates of growth. It is found that pre and post adolescent children follow a seasonal pattern of growth but adolescent children do not. It is suggested that the results are due to an effect of seasonal changes in ultraviolet light availability and the synthesis of vitamin D3 as mediated by the level of maturation of each child.     

The seasonal factors influencing child malnutrition on the Nembi Plateau,Papua New Guinea

A sample of children from the Nembi Plateau, Papua New Guinea, is monitored for nutritional status, episodes of sickness and disease, diets, work activity of mothers, and weight changes; and health and census records are examined for seasonal patterns of disease, deaths, birth, and birth weights. A seasonal pattern in birth weight reinforced by a seasonal pattern in growth performance and compounded by a seasonal pattern of disease suggests that the time of year in which a child is born is important to the child's growth and health. Yields, labor, and ritual surrounding the gardens give rise to the seasonal pattern of events that impinge upon the health of children.     

Growth retardation in weight and catch-up growth following infection by measles and whooping cough among babies of rural Zaire (Lake Tumba)

This study has shown that measles and whooping cough affect growth in weight among babies of rural Zaire (Lake Tumba). The average loss in weight due to measles, is more than twice the amount due to whooping cough. However, the time needed to regain the original growth channel after infection by measles, is about half the time needed to fully catch up after whooping cough. The amount of weight loss is proportional to the child's weight at the onset of the disease. There is no difference in the susceptibility to lose weight after measles or whooping cough, between boys and girls, nor between Oto and Twa. This study has also shown that the effect of measles and whooping cough on the growth in weight, is independent of the season of the hear, although the incidence of these diseases showed a significant seasonal pattern. Finally, this study gives evidence for the fact that the incidence of weight loss one month after the onset of measles or whooping cough is age-related.     

Growth in stem diameter of Larix principis-rupprechtii and its response to meteorological factors in the south of Liupan Mountain, China

Research related to daily and seasonal pattern of stem growth of Larix principis-rupprechtii was carried out with the help of a dendrometer from June to September in 2005 in the Liupan Mountain, Ningxia, Northwestern China. The results indicated that daily fluctuation of stem diameter was rhythmic and it could be divided into three continuous phases: contraction, expansion and stem diameter growth when daily rainfall < 10 mm during the measurement period. Comparatively, it showed a different pattern compared with the former when daily rainfall ≥10 mm and in the subsequent days. Based on the work done by Deslauriers et al. a modified method was designed to calculate daily and cumulative stem growth, and it showed that seasonal pattern of cumulative stem growth was similar among five sample trees. From June and July, stem growth rate was quick and the values were in the range 27.0–44.2 μm per day. Relatively, they took on a slow growth rate from August to September, and the values were under 10 μm per day. And it also showed that there existed a significant difference in stem growth among sample trees, which could be as a result of the difference in tree domain and their positions in the stand. The relationship between daily stem growth and meteorological factors was studied by principle component analysis and partial correlation analysis, and the result indicated that the daily rainfall, daily minimum temperature, daily average solar radiation and vapor pressure deficit were four significant factors which determined the daily stem growth.     

Effects of body-size and season on digestive organ size and the energy balance of cockles fed with a constant diet of phytoplankton

Seasonal variation in size-dependence of seawater clearance rate, absorption efficiency, oxygen consumption, gill area, length of the crystalline style and dry weight of digestive gland was analyzed in cockles Cerastoderma edule from the Mundaka Estuary, Spain. Experimental determinations were performed monthly (from July 1998 to November 1999) in cockles being fed with Tetraselmis suecica (organic content: 87.84 ± 1.95%) at a concentration of 3 mm³/l for 3 days. Analysis of covariance reveals no seasonal differences in both size-dependence of seawater clearance rate and oxygen consumption, which were found to scale to dry body weight with mass-exponents of 0.56 and 0.62, respectively. No significant correlation was found between absorption efficiency and body weight. Mass-exponents for gill area, dry weight of the digestive gland and length of the crystalline style remained constant among seasons showing values of 0.62, 0.34 and 0.82, respectively. Seasonal trends for every physiological determination were calculated for a standard size (200 mg) cockle: standardized clearance rates and oxygen consumptions followed a similar trend with minimum values in winter (≈0.5 l/h and ≈100 μl O₂/h, respectively) and maximum values during spring–summer (≈1.7 l/h and ≈250 μl O₂/h, respectively), whereas absorption efficiency and food throughput time showed both the opposite pattern with highest values corresponding to winter months (≈50–60% and ≈5–6 h, respectively), and lowest (≈30% and ≈3–4 h, respectively) to summer–autumn. Scope for growth exhibited minimum values in winter followed by a rapid increase along the winter–spring transition, maximum values being attained in spring (May) and summer (July). Exponential decline of seasonal values of absorption efficiency associated to rising ingestion rates of organic matter presented an asymptotic minimum at 0.35. Absorption efficiency was positively related to food throughput time, whereas the latter fell to a minimum of 3.548 h with increasing food intake. So, maintenance of throughput time—and consequently absorption efficiency—along with enhanced filtering activity provided cockles with higher absorption rates improving scopes for growth registers during spring and summer. These dynamics might be explained as the consequence of the seasonal digestive adjustments in cockles, which, in fact, were found to increase the size of the digestive organs during that period.     

REPRODUCTIVE PHENOLOGY OF LAMINARIA SACCHARINA (L.) LAMOUR. (PHAEOPHYTA) AT THE SOUTHERN LIMIT OF ITS DISTRIBUTION IN THE NOTHWESTERN ATLANTIC OCEAN1,2

Laminaria saccharina (L) Lamour. Sporophytes were monitored monthly from October 1982 to September 1983 to investigate reproduction phenology and relationshiops to growth paatterns aaat its southern limit of distribution in the northwest Atlantic Ocean (Long Island Soundd). Plants exhibited an annual growth pattern. Growth raate, bladelehgth, maximum width, area, stiipe lehgth an wet weight swhoed the same seasonal pattern and reached maximum values between May and June. Only blade thickness continued to increase tthrooughout the ovservation period. Blade dissintegration occurred dduring August and September. Reproductive sporophytes occurred throughout the observation period; the greatest frequency of appearance occurred in October (43.8%) and June (37.8%). The blade area covered by sori ranged from 2.4% (Janaury) to 6.1% (August). Meiospore release under laboratory conditions was maximum in May and minimum in July. No meio-spores were released in August Sporulation was not correlated with meristematic growth of nitrogen content How ever, reproductive plants were generally larger and thicker throughout the sporulation period, and had a greater carbort content is spring than nonreproductive plants. Fecundity and reproductive success of female gametophytes were maximum in spring and minimum in winter. The growth of early sporophyte stages in the laboratory was greatest in early spring; however, juvenile macroscopic stages were hardly observed in the field during summer months due to warm water temperatures. “Over-summering” of gamelophytes and / or microscopic sporophytes may account for the annual cycle of Laminaria at its southern limit of distribution.     

Seasonal weight changes in male rhesus monkeys (Macaca mulatta)

Adult male rhesus monkeys lose weight during the breeding season and regain it during the nonbreeding season. The annual pattern of maximum weight gain just prior to the onset of breeding resembles the seasonal “fattening” seen in squirrel monkeys, but the period of weight gain is less discrete. The magnitude of weight change is less in younger males, in that sexually immature males gain weight in both seasons, but significantly less during the breeding season. Females do not lose weight during the breeding season. Post hoc analyses revealed no significant correlations between male testosterone levels, dominance ranks, weights, or weight changes. The heaviest animals as juveniles were predictably the heaviest as adolescents. The timing of seasonal changes in testosterone did not correlate with the timing of changes in weight; weight losses followed the rise in testosterone, and weight gains continued until early in the breeding season after testosterone levels had already begun to rise. It is suggested that seasonal hormonal changes may influence activities in individuals and that changes in the activities of particular group members may alter the activity patterns of other group members. This alteration of activity patterns due to group influences on individuals as well as individual influences on the group may explain why hormonal regulation of seasonal weight appears to be indirect and why individuals (juveniles) experiencing no seasonal hormonal changes nonetheless show differences in activity patterns and seasonal weight changes.     

Growth pattern of the Kamars--a primitive tribe of Chhattisgarh,India

A cross sectional study of the physical growth status was made on 655 Kamar children (341 boys and 314 girls), aged 5 to 18 years, in the Raipur district of Chhattisgarh. The study aimed to find out the growth pattern of the Kamar children, which is considered to be a primitive tribe of Chhattisgarh, India and was compared with another Indian tribe and the official data for all India (ICMR). Anthropometric measurements included height, weight, sitting height, biacromial diameter, biilliocrystal diameter, upper arm circumference, calf circumference and measurements of the triceps and subscapular skinfolds. All anthropometric measurements except skinfold thickness exhibit uniform increase with age in both sexes. However, when height and weight of the Kamar boys and girls were compared with the data for other tribes and for all India, the Kamar children (both boys and girls) indicated lower weight and height and the difference showed to be significant, for almost all ages. Kamar boys showed higher anthropometric values than girls in almost all measurements except in biilliocrystal diameter and in measured skinfolds. Poor socio-economic status of this primitive tribe may be one of the reasons for this poor growth pattern. However, in-depth study is necessary in order to arrive at any basic conclusions and to recommend any policy and interventions.     

Seasonal patterns of reproductive and vegetative sink activity in early and late maturing peach (Prunus persica) cultivars

Weekly measurements of fruit growth, fruit respiration and shoot extension growth were made in the field on early (June Lady) and late (O'Henry) maturing cultivars of peach ( Prunus persica L. Batsch). The seasonal patterns of fruit growth and respiration for the two cultivars were very similar except that the early maturing cultivar bloomed a few days earlier than the late cultivar and had a shorter intermediate stage (Stage II) of fruit growth. Maximum rates of fruit respiration per unit weight at 20°C were similar for both cultivars during the first two stages of fruit growth but higher for the early cultivar during the final stage of fruit growth. Maximum fruit growth rates within any particular stage of fruit growth were similar for both cultivars, but the mean fruit weight of the late cultivar was greater at the end of Stage II, because of the extended length of this stage compared to the early cultivar. The final stage of most rapid fruit growth and respiration coincided with the period of most rapid shoot extension growth in the early maturing cultivar but occurred after this period in the late maturing cultivar. Genetic selection for early fruit maturity in peach has apparently had little effect on timing of shoot growth and this may result in increased competition between vegetative and reproductive sinks during peak periods of fruit growth in early maturing cultivars.     

Seasonal change in specific needle weight ofPinus thunbergii

To evaluate the reserve dynamics in pine needles, an index of specific needle weight (SNW; dry weight per unit length of needles) was provided. Developed needles ofPinus thunbergii did not show any additional elongation in their second year. Thus the seasonal change in SNW of developed needles was proved to indicate the dynamics of reserves in needles. SNW showed distinct seasonal change. It increased from autumn to carly spring, followed by a decrease by mid summer. This pattern of change was similar to the change in specific leaf weight (SLW) of evergreen broad leaves in temperate regions. It was concluded that the change in SNW indicated clearly the dynamics of reserves in needles, showing the accumulation in non-growth seasons and the consumption in subsequent growth seasons. The decrease in SNW during the growth season was 10–15% of the maximum found in early spring.     

Weights and measurements of the Manx shearwater, Puffinus puffinus

Large numbers of Manx shearwaters were caught at night at the breeding colony on Skokholm Island, Pembrokeshire, Wales. Most of the birds caught were of known age. In 1973 and 1974 the weight of all age groups was highest in March and then declined to a minimum in June and July. Weight increased slightly in August. It was generally true that the older a bird was, the heavier it was in any particular month, and this effect appeared to hold good until the birds were eight to ten years old. Unlike weight, bill and wing length did not alter with age. It is suggested that, up until an age of about five or six years old, the greater weight of older birds may be due to higher feeding efficiency. This result is therefore related to hypotheses concerning the delayed onset of breeding shown by many seabirds. The seasonal pattern of weight change may reflect the severity of the prevailing feeding conditions.     

Adolescent growth and development in Japanese macaques (Macaca fuscata): Punctuated adolescent growth spurt by season

Adolescent growth of Japanese macaques (Macaca fuscata) was studied. Their growth is composed both of a seasonal cycle of acceleration and deceleration and of linear increases. There is a major growth spurt in linear dimension and body weight at the beginning of the breeding season of the third and fourth year of life in females and males respectively, when they mature reproductively. They show additional accelerated growth in the following year(s). These growth spurts, in total, are considered to correspond with the adolescent growth spurt in humans. Adolescent growth of Japanese macaques is characterized by a punctuation by slower growth and a later start, which is considered to be the product of adaptation to a strongly seasonal environment.     

半个世纪来江苏省丹阳县儿童生长的长期趋势

本文对江苏省丹阳县儿童1936、1956及1985年的生长发育资料进行了对比分析。观察到,半个世纪来,该县7—14岁男女儿童身高分别增长了9.3、11.4厘米,体重平均增长了3.9、4.0公斤,坐高平均增长了4.2、5.0厘米,表现出明显的生长长期加速趋势。1956—1985年阶段的身高每10年增长值显著大于1936—1956年阶段(P<0.01),而体重每10年增长值在两个阶段间无明显差异(P>0.05)。以1985年实测体重均数与估计体重均数比较,女童明显地表现出体重增长相对不足,体型向细长型发展。本文还将丹阳县儿童生长长期趋势与南京市、上海市及日本国同时期、同年龄儿童的生长长期趋势进行了比较。     

Low levels of reserve carbohydrates in reed (Phragmites australis) stands of Kis-Balaton,Hungary

Seasonal dynamics of concentrations of reserve carbohydrates (starch, sucrose, glucose, fructose and their sum denoted as total non-structural carbohydrates, TNC) were followed in five reed stands of Kis-Balaton wetland area in Hungary. The stands included three stands of tall and robust reed, situated in the Ingói area, and two stands of short and subtle reed situated in the downstream part. While both the seasonal pattern and the proportions of single carbohydrate species corresponded to findings for other sites, the absolute concentrations were markedly lower as compared to other European reed stands except lake Fertö in Hungary. The seasonal minimum values ranged from 54 to 87 mg g⁻¹ dry weight. During the seasonal minimum, glucose reached the lowest concentrations (down to 0.01 mg g⁻¹ dry weight) of all carbohydrates measured. The seasonal maximum concentrations of TNC reached 160–270 mg g⁻¹ dry weight. Maximum TNC standing stock ranged from 240 to 520 g m⁻², and was depleted by 60–80% during the period of spring shoot growth. It is proposed that the remaining TNC pool may not suffice to support complete recovery after a subsequent catastrophic event.     

Seasonal and life‐phase related differences in growth in Scarus ferrugineus on a southern Red Sea fringing reef

Temporal trends in growth of the rusty parrotfish Scarus ferrugineus were studied on a southern Red Sea fringing reef that experiences seasonal changes in environmental conditions and benthic algal resources. Length increment data from tagging and recapture were compared among periods and sexes and modelled using GROTAG, a von Bertalanffy growth model. The growth pattern of S. ferrugineus was highly seasonal with a maximum occurring between April and June and a minimum between December and March. Body condition followed the seasonal variation in growth, increasing from April to June and decreasing from December to March. The season of maximum growth coincided with high irradiation, temperature increases and peak abundance of the primary food source, the epilithic algal community. There was a decline in growth rate during summer (July to October) associated with a combination of extreme temperatures and lowered food availability. There were strong sexual size dimorphism (SSD) and life‐history traits. Terminal‐phase (TP) males achieved larger asymptotic lengths than initial‐phase individuals (IP) (L_∞ 34·55 v. 25·12 cm) with growth coefficients (K) of 0·26 and 0·38. The TPs were growing four times as fast as IPs of similar size. Three individuals changed from IP to TP while at liberty and grew eight times faster than IPs of similar size, suggesting that sex change in S. ferrugineus is accompanied by a surge in growth rate. The SSD in S. ferrugineus thus coincided with fast growth that started during sex change and continued into the TP. Faster growth during sex change suggests that the cost associated with sex change is limited.     

Contribution of benthic microalgae to the temporal variation in phytoplankton assemblages in a macrotidal system

Suspended marine benthic microalgae in the water column reflect the close relationship between the benthic and pelagic components of coastal ecosystems. In this study, a 12‐year phytoplankton time‐series was used to investigate the contribution of benthic microalgae to the pelagic system at a site along the French‐Atlantic coast. Furthermore, all taxa identified were allocated into different growth forms in order to study their seasonal patterns. The highest contribution of benthic microalgae was observed during the winter period, reaching up to 60% of the carbon biomass in the water column. The haptobenthic growth form showed the highest contribution in terms of biomass, dominant in the fall‐winter period when the turbidity and the river flow were high. The epipelic growth form did not follow any seasonal pattern. The epiphytic diatom Licmophora was most commonly found during summer. As benthic microalgae were found in the water column throughout the year, the temporal variation detected in the structure of pelagic assemblages in a macrotidal ecosystem was partly derived from the differentiated contribution of several benthic growth forms.     

Do Bertalanffy's growth curves result from optimal resource allocation?

Bertalanffy's equation is commonly used to model indeterminate growth. Bertalanffy claimed that this growth pattern results from growth potential decreasing with age. An alternative approach provided by life history theory predicts that indeterminate growth is optimal for organisms in a seasonal environment and results not from decreasing growth potential but from allocating increasingly less energy with age into growth, and more into reproduction. Bertalanffy's curves are the result of evolutionary optimization and should not be used in optimization models as an assumption, but they can be used as a tool to describe the indeterminate growth pattern phenomenologically.     

Influence of sex, age and season on body weight, energy intake and endocrine parameter in wild living wild boars in southern Germany

Wild boars shot in a hunting area in Baden-Württemberg during three consecutive years (148 males, 205 females) were analysed for insulin-like growth factor 1 (IGF-I) concentrations in blood plasma. Gonadal steroids were determined either in blood plasma (females, progesterone) or adipose tissue (males, androstenone). The age (estimated by the dental pattern) and the carcass weight were recorded. From 159 out of the 353 animals, the stomach content was analysed for total energy and digestibility. Sex differences in carcass weight were only significant in animals above the age of 14 months. Carcass weight was significantly correlated with IGF-I in males but not in females. IGF-I revealed a sex-specific seasonal pattern (maximum concentrations in males, June; in females, October). Additionally, as indicated by analyses of the stomach content, the digestibility of the food had affected IGF-I concentrations. Gonadal steroids revealed the well-known seasonal pattern described in other studies and did not point to a more aseasonal pattern of reproduction when energy supply is artificially increased by baiting.     

Factors controlling the growth of field populations of Hydrodictyon reticulatum in New Zealand

Since Hydrodictyon reticulatum was introduced to New Zealand it has spread rapidly and produced persistent annual nuisance growths in areas where nuisance algal had not occurred previously. Field bioassays were conducted at 10 sites between August 1993 and February 1995 to evaluate the seasonal growth patterns and the factors controlling growth under natural conditions. H. reticulatum exhibited a strong seasonal growth pattern with growth rates up to 0.33 doublings d^-1 from August to March, are duction in growth rate in April and little or no growth from May to July. The H. reticulatum present in New Zealand has are latively low requirement for dissolved inorganic nitrogen (DIN) in comparison with other nuisance species, with its growth rate being saturated at 200 mg m^-3. This and the high affinity for DIN as shown by a K_s of 29 mg m^-3 have been key factors in the establishment of nuisance growths of H. reticulatum in New Zealand. This revised version was published online in August 2006 with corrections to the Cover Date.     

The relationship between obesity and seasonal variation in body weight among elementary school children in Tokyo

Typical patterns of seasonal variation in body weight among Japanese children involve increases during the fall and/or winter and decreases during the summer. However, atypical variations, namely, increases in weight during the summer, have been reported for obese children. The present study examines whether weight gain during the summer (i.e., July through September) is a possible cause of obesity. We examined seasonal changes in weight for 446 elementary school children in Tokyo in six waves between 1972 and 2004. Weight was measured monthly for 6 years in each child and was evaluated by means of time-series analysis. Overall, significant seasonal variations in weight were found in 86% of the children, most of which were typical (i.e., decreases during the summer and increases during the fall, winter, and/or early spring). On the other hand, weight gain in the summer was observed exclusively among obese children. Children whose weight increased during the summer holiday spent most of their time comfortably indoors because of air conditioners, which became popular in 1970s. A possible explanation of the observed weight gain during the summer seems to be changes in life style associated with the use of air conditioning, concomitant with insufficient physical exercise and excessive consumption of food and drink, which could disturb the rhythms of seasonal weight changes and lead to obesity.