Increase In Average Height Research Articles

Do Zinc Supplementation and Physical Exercise Affect Height, H/A z-score, and Academic Performance of Stunted Children in Coronavirus Disease 2019 Pandemic?

BACKGROUND: Stunting in children remains to be a global issue that requires to be addressed. Zinc plays a role in stimulating children’s growth. Research on zinc supplementation and physical exercise in stunted children remains limited in number, specifically during the COVID-19 pandemic.
 AIM: This study aims to analyze the effect of zinc supplementation and physical exercise on height, H/A z-score, and academic performance of stunted children in the COVID-19 pandemic.
 METHODS: The design used in this study was a randomized pre-post test control group design. A total of 30 stunted children aged 8-12 years was divided into 2 groups. The treatment group received 5 ml of zinc syrup 3 times/week for 3 months and practiced physical exercise 3 times/week for 3 months. The control group only practiced physical exercise 3 times/week for 3 months. The analysis of change difference in average height, H/A z-score, and academic performance between the treatment and control groups was performed using independent t-test.
 RESULTS: There was no significant difference in the increase in average height between treatment and control groups (p>0.05). There was increase in the average z-score of H/A in treatment group (0.19) which was higher than in control group (0.14), but the result of independent t-test showed that the mean difference was not significant (p>0.05). The result of independent t-test showed that there was no significant difference in the change in average academic performance scores between treatment and control groups (p>0.05).
 CONCLUSION: There was no significant difference in the increase in height, H/A z-score, and academic performance of stunted children between the treatment and control groups. Further study is necessary to conduct with a minimum of 6 months of intervention in the non-pandemic period.

Changes in weight and height among Chinese preschool children during COVID-19 school closures.

Background and objectivesCOVID-19-related school closures may increase the prevalence of childhood obesity, which has aroused public concerns. We aimed to analyze the weight and height changes in Chinese preschool children during the COVID-19-related school closures period.MethodsA total of 124,603 children from multi-city kindergartens in China were included in this study. We evaluated the prevalence of overweight and obese in preschool children experienced school closures, and compared the changes in BMI, weight, and height of preschool children among COVID-19 school closures period, the same period last year and the same period the year before last.ResultsAfter the school closures, childhood obesity prevalence increased, whereas overweight prevalence decreased. During school closures, the average increase in height was about 1 cm less as compared with the same period last year and the year before last, but no noteworthy difference in the weight change was observed among the three periods.ConclusionsDuring COVID-19 school closures, children’s height increase seemed to be more affected than weight change. Innovative, robust, and highly adaptable strategies should be taken to increase physical activity, reduce sedentary time and promote healthy diets, to minimize the adverse impact of school closures.

Growth of Api-Api (Avicennia alba) Rehabilitation in Kedaburapat Village, Rangsang Pesisir City Meranti Islands District

This research was conducted in July-October 2020. Observation and data collection of Avicennia alba growth was carried out in the mangrove forest rehabilitation area, Kedaburapat, Kepulauan Meranti Regency. The purpose of this study was to analyze the growth of A. alba as on rehabilitation project based on the height and diameter planted in the coastal area of Kedaburapat, Kepulauan Meranti Regency. A survey method was conducted to obtain primary data. The data collected included the height and diameter of A. alba stems as well as measurements of water quality. The results of the research showed that the average height increase A. alba on the transect was 7.59-19.86 cm/month. The average value of the increased diameter based on the transect was 1.05-3.11 mm/month. Meanwhile, the average height by zone was 8.07-16.13 cm/month. The average value of the increased diameter by zone was 1.03-2.70 mm/month

Implementation of Family Psychoeducation Therapy to Additional Height in Stunting Children

Indonesia is currently still facing serious problems regarding stunting. The high prevalence of stunting in Indonesia is a chronic problem related to poverty, low education, and inadequate environmental and health services. Efforts made are improving the nutritional status of the community. The role of parents is very important in fulfilling children's nutrition. For this reason, treatment is needed through an approach to the family that can have an impact on behavior change within the family in carrying out family functions caring for family members with stunting, one of which is implementing family psychoeducation therapy. The purpose of this study was to determine the effect of family psychoeducation therapy on height gain in stunting children. This study used a quasi experimental research method with a pretest-posttest design. The sampling technique used purposive sampling of 34 respondents consisting of 2 groups, namely 17 respondents in the intervention group and 17 respondents in the control group. Assessment using instruments from the WHO-NCHS Standard deviation Z-Score TB / U. The data analysis used was the dependent sample t 2 test and independent sample t 2 test for bivariate. The results showed that there was an effect of family psychoeducation therapy on height gain and there was a significant difference in the average height increase in stunting children between the intervention group and the control group.

Filling the weight gap: Estimating body weight and BMI using height, chest and upper arm circumference of Swiss conscripts in the first half of the 20th century

We estimate weight and BMI values based on height, chest circumference, and mid upper arm circumference measures of Swiss conscripts in the city of Zurich for each year between 1904 and 1932. Height, chest circumference, and mid upper arm circumference were measured each year from 1904 to 1951. Body weight is available from 1933 to 1951. We used prediction equations from the literature, and also developed our own equations, which we tested and validated on the dataset from 1933 to 1951. We used a representative sample of usually 19-year-old Swiss males (N = 88,792, coverage > 88 %). There was an increase in average height and chest circumference between 1904 and 1951. During both world wars, chest circumference, mid upper arm circumference, weight, and BMI decreased, while height stagnated. Overall mean weight and BMI increased from 1904 to 1951, but decreased during the Great Depression. After World War II, weight quickly returned to the pre-war and pre-Great Depression level, while BMI had not reached the 1933 level by 1951. Average weights of the lower and middle socioeconomic groups were catching up with average weight of the upper socioeconomic group from 1904 to 1951. The convergence in height is less pronounced. Finally, we show that it is possible to accurately predict mean weight and BMI from other anthropometric measurements. We suggest that our estimation approach could be replicated for other historical populations to obtain more information on how nutritional status changed over time.

Linear and volumetric gain after vertical bone augmentation in the posterior mandible using an autologous cortical tenting method

This study was performed to evaluate the linear and volumetric effects of a technique for reconstruction of the posterior atrophic mandible, including the final bone gain of the graft, by three-dimensional assessment. Thirteen individuals were recruited into the study and submitted to a total of 15 mandibular autogenous bone block surgeries. Cone beam computed tomography images were obtained at three different times. Bone graft length and thickness, and the volume, height, and width of the graft were measured. Data were compared statistically among the time points using the Friedman test, and cluster analysis was performed to identify the association between the study variables and the resorption rate (α = 0.05). Linear analysis of the width and height of the recipient area at the different time points revealed a statistically significant difference. The final average increase in height was 1.6 mm; all subjects showed an average volume gain of 3.412mm3, and 77% of the subjects showed an average graft resorption of 0.688mm3 construction of three-dimensional vertical defects of the posterior mandible resulted in good healing with minimal complications and minimal bone graft resorption, favouring vertical bone gain.

Development of regional variety of the biological standard of living in the Netherlands, 1812–1913

This study focuses on regional patterns in stature in Dutch society during the 19th and early 20th century (1813–1913). To analyze regional patterns and transitions the HSN Database Giants is used. Results confirm that in the first period (1830–1860) differences in the biological standard of living were substantial. The less market-oriented inland provinces had the highest level. This is in line with the Komlos-hypothesis. The modernization of the Dutch economy in the second half of the 19th century was accompanied by a substantial increase in average height and a reversal of the spatial pattern of living standards as modernization was more important in the market oriented regions. Nevertheless, regional differences remained substantial and there was no pattern of convergence. Conscripts from the market-oriented coastal provinces took over the lead from the inland provinces. I tested for an urban premium during the last period (1890–1913). This was confirmed, although it did not manifest itself in cities like Amsterdam and Rotterdam, but rather in medium-sized and small cities.

Long-Run Effects of Public Health Insurance on the Health of Children in Mexico

Background: In December 2006, Seguro Popular (SP) implemented the Medical Insurance Century XXI program (SMSXXI) to provide public healthcare insurance to children under five years old who lack social security. SMSXXI aims to increase access to health services, reduce out-of-pocket health-related expenditures (OOPHE), and lower health inequities. Methods: We assessed the effects of SMSXXI on health outcomes and financial protection for Mexico's children using multiple nationally representative surveys and administrative data sources spanning the period between 2001 and 2016. The identification of effects relied on detailed hospital level affiliation data mapping the geographical expansion of the program's coverage across the country over time. The final outcomes were neonatal and infant mortality, self-reported morbidity (health status, flu, and diarrhea) and child's height. Intermediate outcomes were OOPHE, hospital discharges and quality of service provision. Effects controlled for fixed and time-variant confounders using double- and triple-difference estimation strategies. Where feasible, we also estimated effects using exogenous variation in program eligibility rules that limited enrollment in SMSXXI to children born after December 1, 2006. Findings: SMSXXI reduced the infant mortality rates of conditions covered by the program by 5.3%. The effects were largest in high baseline mortality areas. Long-run health effects, eight years after the onset of SMSXXI, were reflected in a 0.44 cm average increase in height for birth cohorts exposed to the program, and an average effect on height of almost 1cm for low-income populations. Approximately three to six years after the program started, children reported having better health status and lower incidence of the flu and diarrhea. The program led to a 10% reduction in OOPHE, primarily from hospital-related expenses. No effects were detected on hospital discharges, suggesting that the program may not have increased utilization. Rather, improvements in the quality of healthcare and specialized personnel are likely channels driving improvements in health outcomes. Interpretation: SMSXXI covers uninsured, primarily low-income populations who may be most at risk from the financial and health consequences of costly medical interventions. The program transfers resources from the federal level to states and providers for the enrollment and treatment of children under five years old. Transfers are conditioned on the compliance of medical facilities with accreditation standards (criteria of capacity, quality and safety for the patient). Funds are used to strengthen local health services through the purchase of equipment and staffing of medical specialists. We use previously unexploited sources of exogenous variation in program assignment to identify causal effects on health and financial risk. Results suggest that SMSXXI reduced infant mortality, improved long-run health as proxied by self-reported morbidity and child height, and protected low-income families from the adverse economic consequences of health shocks. Funding: Funding for this study was provided through Inter-American Development Bank (IDB) Technical Cooperation ME-T1307. Declaration of Interest: Dr. Celhay has nothing to disclose. Dr. Martinez has nothing to disclose. Mr. Munoz has nothing to disclose. Mrs. Perez has nothing to disclose. Dr. Perez Cuevas has nothing to disclose. Ethical Approval: The study consists in a secondary data analysis of several databases; all these databases have the de-identified data; thus, it is not possible to trace any of the data to the actual individual. In accordance to the Internal Regulation of the Interamerican Development Bank, this secondary data analysis can be considered exempt of institutional review board approval.

Analysis and Intervention of Severe Acute Malnutrition in Children at an Urban Public School in Mumbai, India

Background: There is a dearth of information regarding trends of malnutrition and weight status in children from rapidly developing economies like India. Objectives: The aim of this study is to analyze the dynamics of malnutrition in a group of school children from India, and then provide interventions for the children that have severe acute malnutrition. Methods: Children that were found to lie between −3 to −4 SD of parameters of BMI, height for age and weight for age were labeled as SAM. Children that were screened for wasting and fell between −2 to −4 SD were also included under the label of SAM. All participants were also given a prototype 1500-calorie diet to follow for the entire duration and 6 weekly sessions were taken for the parents on various topics on nutrition. Results: Quantitative analysis showed a great improvement in weights and heights of severely malnourished children. The average increase in weight of all children that participated in the study was 9.09% and the average increase in height was 1.39%. The weekly sessions given to the parents on various nutrition topics could be the cause of high compliance to the diet given to the children. Conclusion: Malnutrition is still a very big problem in developing countries like India. Basic interventions like an improvement in diet, education about micronutrients and balanced diet, and food-based interventions in severe malnutrition can lead to a great improvement in the health and development status of children.

Genetic variation of height growth rhythm between clones of Larix kaempferi × L. gmelini based on logistic models

Fifty-three larch interspecific hybrid clones (Larix kaempferi × L. gmelini) and their parent clones were used for growth curve analysis of height variations. The growth curves of the 55 clones were ‘S’-shaped and 36 exhibited similar curves as the male parent. The coefficients of the logistic models were higher than 0.943, indicating that our results were effective in the simulation of the growth curves. ANOVA analysis showed significant differences in height of different clones (P < 0.01). Average date of maximum height growth was Day 173, and average duration of rapid growth lasted for 50 days. Annual average increase in height was 9.7 cm d−1 and daily average increase was 0.2 cm. The ratio of GR to the total annual increase in height ranged from 51.2 to 68.8%, with the average being 59.8%. There was a positive correlation between k values and plant heights which benefited from the evaluation of early plant height. There was also a positive correlation between GR (growth stage), GD (plant height) and annual increase in height. These results are informative to the evaluation of the elite clone selection and provide a theoretical basis for breeding and management.

Superhydrophobic microtextured polycarbonate surfaces

A novel approach for fabrication of superhydrophobic polycarbonate (PC) surfaces has been developed based on purely physical process. Unlike the classical routes, which heavily rely on the surface chemical modification, the present route involves fabrication of microtextured Si master using high power pulsed laser and subsequent thermal replication of microtexture onto PC surface. The water droplet beads up on the microtextured PC in a Cassie–Baxter state exhibiting superhydrophobic nature of the surface. Average height of the micro-pillars formed on replicated PC surfaces played a crucial role in governing the superhydrophobic properties of the resulting microtextured surfaces. The water contact angle could be tailored over a wide range, from 82° for smooth PC surface to 155°, with an increase in average height of the micro-pillars from 1.34μm to 6.68μm. The infrared (IR) spectroscopy analysis revealed that the PC surface does not undergo any chemical change during thermal replication and further implied that the resulting superhydrophobic behavior was solely due to the physical modification of the surface. Moreover, the microtextured PC has been shown to be a perfect master for replication of microtexture onto other type of polymers such as polydimethylsiloxane (PDMS) in bulk and in thin film forms. Given the facile nature of the present technique and ease of fabrication, we believe that the present route is quite promising for large-scale production of PC based superhydrophobic surfaces. These surfaces find several potential applications such as anti-corrosive, anti-icing and self-cleaning surfaces, coatings inside of water pipes for frictionless flow and so on.

Preliminary assessment of growth and survival of green alder (Alnus viridis), a potential biological stabilizer on fly ash disposal sites

This paper presents preliminary assessment of seedling survival and growth of green alder (Alnus viridis (Chaix) DC. in Lam. & DC.) planted on fly ash disposal sites. This kind of post-industrial site is extremely hard to biologically stabilize without top-soiling. The experiment started with surface preparation using NPK start-up mineral fertilizer at 60–36–36 kg ha−1 followed by initial stabilization through hydro-seeding with biosolids (sewage sludge 4 Mg ha−1 dry mass) and a mixture of grasses (Dactylis glomerata L. and Lolium multiflorum Lam.) (200 kg ha−1). Subsequently, three-years-old green alder seedlings were planted in plots on two substrate variants: the control (directly on combustion waste) and plots with 3 dm3 lignite culm from a nearby mine introduced into the planting pit. Five years of preliminary monitoring show good survival seedling rates and growth parameters (height (h), average increase in height (Δh), number of shoots (Lo) and leaf nitrogen supply in the fly ash disposal habitat. Treatment of the site with a combination of lignite culm in planting pits and preliminary surface preparation by hydro-seeding and mineral fertilization had the most positive effect on green alder seedling parameters. The results indicate that it is possible and beneficial to use green alder for biological stabilization on fly ash disposal sites.

Tingkat Pertumbuhan Anakan Sengon di Lahan Bekas Terbakar pada Kebun Penelitian dan Percobaan Universitas Muhammadiyah Palangkaraya

Wood Sengon (Paraserianthes falcataria) is a versatile timber for light construction, crafts, cigar boxes, veneer, plywood, matches, musical instruments and pulp. Sengon planted as shade trees, ornamental plants, and reforestation. The problems that faced the burnt peat is related to determining the appropriate type of soil acidic and resistant to non periodic inundation. Besides it takes a special kind of seeds, peat forest encountered many obstacles such as puddles, accessibility and prone to burning. From the observations during the three-month field observations obtained an average height increase in the amount Sengon of 11,46 cm tillers. This indicates a high level of each plant is very significant compared to the increase in diameter and number of leaves of plants, which is respectively 0.88 and 1.57 mm strands.

G031014 デジタルホログラフィック顕微鏡を用いた純チタンの引張りにおける微視的表面高度変化とすべり線分布の関係に関する検討([G031-01]材料力学部門,一般セッション : 非鉄金属の強度と変形(1))

Polycrystalline metals are composed of grains with different crystal orientations and sizes, and show inhomogeneous elastic-plastic deformation behavior. Especially for grains on the surface, the inhomogeneous deformation appears accompanied by the change in the height distribution. On the other hand, recently, digital holographic microscope is used to measure the height distribution on the materials surface with high accuracy in a short time. In this study, a cyclic tensile test of polycrystalline pure titanium was carried out and the change in the height distribution was studied using the digital height correlation method. Increase in average height of each grain by unit load in elastic region correlated with those in plastic region, which suggests that the plastic deformation is predictable from the elastic deformation.

Late childhood and adolescence growth sensitivity to political transition: the case of South African Cape Coloured schoolchildren during and post-apartheid

South Africa underwent major social and economic change between 1987 and 1995. The release of Nelson Mandela in February 1990 proclaimed an end to the political system of apartheid, and the first freely elected non-White government in 1994 instigated social and economic reforms aimed at alleviating the consequences of apartheid. This paper aims to examine the impact of these socio-economic and political changes on height, weight and body mass index (BMI) in childhood and late adolescence. An analysis was carried out of longitudinal data of 258 urban and rural South African Cape Coloured schoolchildren (6–18 years old) across the transitional periods from apartheid between 1987 and 1990, to this transition between 1991 and 1993, and finally to post-apartheid between 1994 and 1995. The anthropometric measures were standardized into age independent Z-scores. Analyses of variance with repeated measures were conducted to examine the growth in height, weight and BMI across these periods. The results show a significant main effect of measurement periods on height, weight and BMI Z-scores. Across time, the subjects increased in overall size, height, weight and BMI. For all the anthropometric measures there was a significant interaction effect between measurement period and sex, but none between measurement period and SES. The average increase in height, weight and BMI across time differed significantly for girls and boys, the average z-scores being greater in girls than in boys. For boys, there was little difference in height, weight and BMI Z-scores according to SES, and little increase across periods. Girls were generally taller, heavier with greater BMI than boys, and their scores increased across the time periods. High SES girls were taller, heavier and had higher BMI than low SES girls. Across the measurement periods, BMI and weight somewhat converged between the high and low SES girls. In the discussion these differences reflecting social sex distinctions are addressed.

Infant mortality and adult stature in Spain

This paper presents new evidence concerning the relationship between environmental conditions in the year of birth (as reflected in the infant mortality rate (IMR) and gross domestic product per capita) and adult health (adult height). We perform an analysis across Spanish regions for cohorts born between 1961 and 1980, a period when the country underwent a socioeconomic and political transformation. We find that a reduction in the IMR of 30 individuals per 1000 (similar to that achieved by Spain between 1961 and 1980) explains an increase in average height of about 2.7 cm, about 70% of the gain in average adult stature during this period. Our results, which are robust to several adjustments, suggest that the burden of disease in childhood can have long-lasting effects on health, and that these are reflected in differences in adult stature.

Atomic force microscopy differentiates discrete size distributions between membrane protein containing and empty nanolipoprotein particles

To better understand the incorporation of membrane proteins into discoidal nanolipoprotein particles (NLPs) we have used atomic force microscopy (AFM) to image and analyze NLPs assembled in the presence of bacteriorhodopsin (bR), lipoprotein E4 n-terminal 22k fragment scaffold and DMPC lipid. The self-assembly process produced two distinct NLP populations: those containing inserted bR (bR-NLPs) and those that did not (empty-NLPs). The bR-NLPs were distinguishable from empty-NLPs by an average increase in height of 1.0 nm as measured by AFM. Streptavidin binding to biotinylated bR confirmed that the original 1.0 nm height increase corresponds to br-NLP incorporation. AFM and ion mobility spectrometry (IMS) measurements suggest that NLP size did not vary around a single mean but instead there were several subpopulations, which were separated by discrete diameters. Interestingly, when bR was present during assembly the diameter distribution was shifted to larger particles and the larger particles had a greater likelihood of containing bR than smaller particles, suggesting that membrane proteins alter the mechanism of NLP assembly.

Weight loss and the Effect on Stature in Children During a Residential Intervention Program

Weight loss is generally high in residential weight-loss programs but the effect of a large weight loss on linear growth is not known. We report the weight loss and the influence on linear growth in a large group of children during a residential weight-loss program focusing on nutrition and physical activity. In a longitudinal noncontrolled intervention study of 990 overweight children (540 girls) attending the weight reduction program from 1990 to 2001 for about 11 weeks (age: 10-14 years, mean BMI-standard deviation score (SDS) at enrollment: 2.83) weight and height were measured initially and after end of treatment. Weekly measurements of height and weight were performed on 138 children. The children lost on average 9.4 kg, reduced their BMI by 4.5 kg/m(2) and BMI-SDS by 0.98. In a multiple regression analysis (P < or = 0.001) weight loss was higher in boys than girls (1.7 kg), higher if the weight was higher at admission (-0.192 kg/kg at baseline) and was positively associated with duration of stay (-80 g/day). Initially the boys' BMI-SDS was higher than the girls' BMI-SDS (P < or = 0.05) but after 8 weeks of treatment the boys had lower BMI-SDS than the girls. There was no negative effect on linear growth during the treatment; on the contrary, linear growth accelerated during the stay as the average increase in height was 2.38 cm corresponding to 11.4 cm/year. In conclusion the children lost close to 1 kg/week during the stay without any negative effect on linear growth. The cause of the linear growth acceleration needs further investigation.

Lava dome growth and mass wasting measured by a time series of ground‐based radar and seismicity observations

Exogenous growth of Peléean lava domes involves the addition of lava from a central summit vent and mass wasting on the flanks as rockfalls and pyroclastic flows. These processes were investigated at the Soufrière Hills Volcano, Montserrat, between 30 March and 10 April 2006, using a ground‐based imaging millimeter‐wave radar, AVTIS, to measure the shape of the dome and talus surface and rockfall seismicity combined with camera observations to infer pyroclastic flow deposit volumes. The topographic evolution of the lava dome was recorded in a time series of radar range and intensity measurements from a distance of 6 km, recording a southeastward shift in the locus of talus deposition with time, and an average height increase for the talus surface of about 2 m a day. The AVTIS measurements show an acceleration in lava extrusion rate on 5 April, with a 2‐day lag in the equivalent change in the rockfall seismicity record. The dense rock equivalent volumetric budget of lava added and dispersed, including the respective proportions of the total for each component, was calculated using: (1) AVTIS range and intensity measurements of the change in summit lava (∼1.5 × 106 m3, 22%), (2) AVTIS range measurements to measure the talus growth (∼3.9 × 106 m3, 57%), and (3) rockfall seismicity to measure the pyroclastic flow deposit volumes (∼1.4 × 106 m3, 21%), which gives an overall dense rock equivalent extrusion rate of about 7 m3·s−1. These figures demonstrate how efficient nonexplosive lava dome growth can be in generating large volumes of primary clastic deposits, a process that, by reducing the proportion of erupted lava stored in the summit region, will reduce the likelihood of large hazardous pyroclastic flows.

Grass, rainfall and herbivores as determinants of Acacia erioloba (Meyer) recruitment in an African savanna

Acacia species in arid environments are thought to only establish in years of above-average rainfall, so should exhibit cohorted or pulsed recruitment. I studied population demography of Acaciaerioloba Meyer in semi-arid savanna in the Kimberley area (mean annual precipitation = 425 ± 132 mm), South Africa, to establish whether they recruit episodically. This species was found to have a sapling bank at the sites, indicating that even though cohorted recruitment probably occurs, it is not the primary factor limiting recruitment to larger size classes. A. erioloba saplings given supplementary water and protection from herbivory showed significantly less height growth than saplings given water but not protected from herbivores, and grass within exclusion plots was taller and denser than outside of exclusion plots. The generalized linear model, although finding a significant difference between watered and protected and watered and unprotected saplings, explained only 16% of variation in growth, demonstrating the importance of factors other than competition from grass when rainfall is above-average. Average height increase across all treatments for a growing season was small (43.1 ± 30.81 mm), suggesting most investment is belowground. A. erioloba sapling below surface stem diameter correlated positively with aboveground growth, indicating larger, and presumably older, individuals grow faster. When grass was removed around saplings, growth rates were not significantly greater than for saplings surrounded by grass, over a growing season. Thus, in these study sites, pulsed events allow seedlings to establish, and then saplings slowly accumulate over many growing seasons within the grass sward, owing to slow aboveground growth combined with competition from grass in absence of grazers. Release events, e.g., heavy grazing combined with good rainfall, may allow mass release, giving the impression of cohorted or pulsed recruitment.