Pediatric inpatient hospital resource use for congenital heart defects

Background: Congenital heart defects (CHDs) occur in approximately 8 per 1000 live births. Improvements in detection and treatment have increased survival. Few national estimates of the healthcare costs for infants, children and adolescents with CHDs are available. Methods: We estimated hospital costs for hospitalizations using pediatric (0–20 years) hospital discharge data from the 2009 Healthcare Cost and Utilization Project Kids' Inpatient Database (KID) for hospitalizations with CHD diagnoses. Estimates were up‐weighted to be nationally representative. Mean costs were compared by demographic factors and presence of critical CHDs (CCHDs). Results: Up‐weighting of the KID generated an estimated 4,461,615 pediatric hospitalizations nationwide, excluding normal newborn births. The 163,980 (3.7%) pediatric hospitalizations with CHDs accounted for approximately $5.6 billion in hospital costs, representing 15.1% of costs for all pediatric hospitalizations in 2009. Approximately 17% of CHD hospitalizations had a CCHD, but it varied by age: approximately 14% of hospitalizations of infants, 30% of hospitalizations of patients aged 1 to 10 years, and 25% of hospitalizations of patients aged 11 to 20 years. Mean costs of CHD hospitalizations were higher in infancy ($36,601) than at older ages and were higher for hospitalizations with a CCHD diagnosis ($52,899). Hospitalizations with CCHDs accounted for 26.7% of all costs for CHD hospitalizations, with hypoplastic left heart syndrome, coarctation of the aorta, and tetralogy of Fallot having the highest total costs. Conclusion: Hospitalizations for children with CHDs have disproportionately high hospital costs compared with other pediatric hospitalizations, and the 17% of hospitalizations with CCHD diagnoses accounted for 27% of CHD hospital costs. Birth Defects Research (Part A) 100:934–943, 2014. © 2014 Wiley Periodicals, Inc.     

Patterns of spatio-temporal variation in the survival rates of a viviparous lizard: the interacting effects of sex,reproductive trade-offs,aridity, and human-induced disturbance

Examination of the spatial and temporal variation in survival rates provides insight on how the action of natural selection varies among populations of single species. In this study, we used mark-recapture data from seven populations of the viviparous lizard Sceloporus grammicus in Central Mexico and a multi-model inference framework to examine interpopulation variation in the survival of adult males and females. We aimed to analyze the potential effects of aridity, human-induced disturbance, and reproductive costs on the survival rates of these lizards. For females in particular, we also searched for a negative relationship between litter size (adjusted for female size) and female survival. Our results demonstrate seasonal changes in survival for males and females. In three out of our seven study sites female survival decreased during the birthing season. In contrast, male survival did not appear to decrease during the mating season. We found an interaction between site-specific aridity and reproductive season affecting female survival. A decrease in female survival during the birthing season was observed in relatively arid sites. In one of these arid sites we found a negative effect of size-adjusted litter size on female survival: females producing more offspring than those expected for their size were more likely to die. This result represents evidence of a physiological trade-off for gravid females occurring in at least one of the studied populations. Interpopulation variation in the degree of human-induced disturbance could not explain the observed patterns of spatial variation in survival rates. Our results demonstrate wide variation in sex-specific survival patterns of this viviparous lizard and provide evidence that negative associations between reproduction and survival are highly dependent on the local environmental conditions.     

Changes in mesophyll anatomy and sink–source relationships during leaf development in Quercus glauca, an evergreen tree showing delayed leaf greening

Changes in mesophyll anatomy, gas exchange, and the amounts of nitrogen and cell wall constituents including cellulose, hemicellulose and lignin during leaf development were studied in an evergreen broad‐leaved tree, Quercus glauca, and in an annual herb, Phaseolus vulgaris. The number of chloroplasts per whole leaf in P. vulgaris increased and attained the maximal level around 10 d before full leaf area expansion (FLE), whereas it continued to increase even after FLE in Q. glauca. The increase in the number of palisade tissue cells per whole leaf continued until a few days before FLE in Q. glauca, but it had almost ceased by 10 d before FLE in P. vulgaris. The radius and height of palisade tissue cells in Q. glauca, attained their maximal levels at around FLE whereas the thickness of the mesophyll cell wall and concentrations of the cell wall constituents increased markedly after FLE. These results clearly indicated that, in Q. glauca, chloroplast development proceeded in parallel with the cell wall thickening well after completion of the mesophyll cell division and cell enlargement. The sink–source transition, defined to be the time when the increase in daily carbon exchange rate exceeds the daily increase in leaf carbon content, occurred before FLE in P. vulgaris but after FLE in Q. glauca. During leaf area expansion, the maximum daily increase in nitrogen content on a whole leaf basis (the maximum leaf areas were corrected to be identical for these species) in Q. glauca was similar to that in P. vulgaris. In Q. glauca, however, more than 70% of nitrogen in the mature leaf was invested during its sink phase, whereas in P. vulgaris it was 50%. These results suggest that Q. glauca invests nitrogen for cell division for a considerable period and for chloroplast development during the later stages. We conclude that the competition for nitrogen between cell division and chloroplast development in the area of expanding leaves can explain different greening patterns among plant species.     

A novel model-free approach for reconstruction of time-delayed gene regulatory networks

Many important biological processes (e.g. cellular differentiation during development, aging, disease etiology etc.) are very unlikely controlled by a single gene instead by the underlying complex regulatory interactions between thousands of genes within …     

Breeding Experience and not Age Modulates the Song Development of Pied Flycatchers (Ficedula hypoleuca)

In songbirds, the development of the species‐specific adult song involves a learning process that varies in extension. In species that incorporate new song elements throughout life (open‐ended learners), variation in male song composition could be the result of either age or breeding experience. Using data from 16 yr of fieldwork on pied flycatchers (Ficedula hypoleuca), we aimed to disclose the individual contribution of these two factors on the species song characteristics, as well as their relation with morphology and plumage color changes. Finally, we explored whether any of the song or physical features could predict the probability of males returning to the breeding site. We found that the song characteristics of the first‐time breeders did not differ between age classes, except for the total number of syllables per song, which was higher in the 1‐year‐old than in the 2‐year‐old males. However, we found that song variables associated with complexity (song and sample versatilities and repertoire size), increased significantly from the first to the second breeding season. Males showed delayed plumage maturation, with 1‐year‐old males being browner than the 2‐year‐old males independently of their breeding experience. Morphology, however, was not affected by age or breeding experience. The probability that males returned to the breeding site was not associated with song or physical features. Considering that some song learning occurs during the breeding period and that some males may skip the first breeding season, selective pressures may have been established for song complexity to be an honest indicator of breeding experience rather than age.     

Time and travelling costs during chick‐rearing in relation to habitat quality in Little Owls Athene noctua

In many bird species, parents adjust their home‐ranges during chick‐rearing to the availability and distribution of food resources, balancing the benefits of energy intake against the costs of travelling. Over recent decades, European agricultural landscapes have changed radically, resulting in the degradation of habitats and reductions in food resources for farmland birds. Lower foraging success and longer foraging trip distances that result from these changes are often assumed to reduce the reproductive performance of parents, although the mechanisms are not well understood. We tested the behavioural response of chick‐rearing Little Owls Athene noctua to variation in habitat diversity in an agricultural landscape. We equipped females with GPS loggers and received adequate range‐use data for 19 individuals (6063–14 439 locations per bird). In habitats dominated by homogeneous cropland habitats, home‐ranges were over 12 ha in size, whereas in highly diverse habitats they were below 2 ha. Large home‐ranges were associated with increased flight activity (117% of that of birds in small home‐ranges) and distances travelled per night (152%), increased duration of foraging trips (169%) covering larger distances (246%), and reduced nest visiting rates (81%). The study therefore provides strong correlative evidence that Little Owls breeding in monotonous farmland habitats expend more time and energy for a lower benefit in terms of feeding rates than do birds in more heterogeneous landscapes. As nestling food supply is the main determinant of chick survival, these results suggest a strong impact of farmland characteristics on local demographic rates. We suggest that preserving and creating islands of high habitat diversity within uniform open agricultural landscapes should be a key target in the conservation of Little Owl populations.     

Roles of maternal effects in maintaining genetic variation: Maternal storage effect

Understanding the maintenance of genetic variation remains a central challenge in evolutionary biology. Recent empirical studies suggest the importance of temporally varying selection, as allele frequencies have been found to fluctuate substantially in the wild. However, previous theory suggests that the conditions for the maintenance of genetic variation under temporally fluctuating selection are quite restrictive. Using mathematical models, we demonstrate that maternal genetic effects, whereby maternal genotypes affect offspring phenotypes, can facilitate the maintenance of polymorphism in temporally varying environments. Maternal effects result in mismatches between genotypes and phenotypes, thereby buffering the influence of selection on allele frequency. This decreases the magnitude of allele‐frequency fluctuations and creates conditions for the maintenance of variation when selection causes fluctuations. Therefore, maternal effects may result in a temporal storage effect (“maternal storage effect”). On the other hand, when selection does not cause fluctuations (e.g., linear negative frequency‐dependent selection), maternal genetic effects moderate the relative importance of selection compared to genetic drift and promote stochastic allele extinction in finite populations. Thus, maternal effects can play an important role in the maintenance of polymorphism, but the direction of the effect depends on the nature of selection.     

The adjustment of reproductive threshold to prey abundance in a capital breeder

1. Many organisms rely upon stored energy reserves to support reproduction and do not initiate breeding until their reserves exceed some 'reproductive threshold'. However, the determinants of such thresholds are poorly understood; for example, we do not know if they are fixed (invariant) or respond dynamically to fluctuations in resource availability.
2. An 8-year field study on water pythons ( Liasis fuscus Peters 1873) in tropical Australia shows that individual female pythons adjust their reproductive thresholds in response to annual variation in prey abundance.
3. In every year of the study, female pythons that reproduced were in better condition (mass relative to body length) than non-reproductive females. However, in years with low abundance of rats, female pythons reproduced despite being in relatively poor condition. Indeed, the mean condition of reproductive pythons in one particularly 'bad' year was as low as the mean condition of non-reproductive females in a 'good' year.
4. Clutch sizes were slightly reduced in a 'bad' year, but the main effect of the lowered threshold was greater emaciation of the females after laying.
5. Recapture records of marked snakes show that the annual variation in thresholds is due to flexibility of individual females, not to differential representation of cohorts with different reproductive thresholds.
6. The dynamic adjustment of threshold levels fits well with predictions from life-history models and is likely to be a widespread phenomenon.     

The mechanism of delayed selfing in Collinsia verna (Scrophulariaceae)

Collinsia verna, blue-eyed Mary, has floral attributes of an outcrossing species, yet most flowers readily self-pollinate under greenhouse conditions. Here we describe the mechanism of self-pollination in C. verna via changes in relative positions of the stigma and anthers and late timing of receptivity, resulting in delayed selfing. Each flower contains four anthers that dehisce sequentially over ∼1 wk. Pollen that is not collected by pollinators accumulates in the keel petal and retains high viability (>80% pollen germination) up to the time of corolla abscission. The stigmatic surface does not become receptive until after the third anther dehisces. This overlap in the sexual phases is concurrent with a change in herkogamy during floral development. In most flowers (70%), the stigma has moved to the front of the keel and is positioned near the anthers when the third anther dehisces. Under field conditions, fruiting success of plants within pollinator exclosures was ∼75% of the fruiting success in open-pollinated plants (33% fruiting success via autogamy vs. 44% fruiting success, respectively). Collinsia verna plants in pollinator exclosures exhibit variation in autogamy rates within natural populations (range 0–80%). In addition, only half of naturally pollinated, receptive flowers examined had pollen tubes growing in their styles. In contrast, shortly after corolla abscission, nearly all flowers examined (96%) had pollen tubes in their styles. Thus we find that in C. verna, autogamy occurs late in floral development, which has the potential to provide substantial reproductive assurance, and that individuals vary in their ability to set fruit through this mechanism. We suggest that delayed selfing mechanisms may be overlooked in other species and that variable pollinator availability may play a significant role in the maintenance of mixed mating in species with delayed selfing, such as C. verna.     

利用延迟荧光研究DCMU对植物光合的影响

敌草隆（DCMU）阻断植物光合器官类囊体膜上的电子从QA到QB的传递。延迟荧光（DF）是光系统Ⅱ（PSⅡ）反应中心电荷分离效率的内在探针。本文以菠菜叶片作为实验材料,从DF衰减动力学及其总强度的变化研究了DCMU对植物光合作用的影响。DCMU作用后叶片DF衰减动力学曲线表明在快相部分有明显上升趋势,而慢相部分出现下降。不同DCMU浓度处理叶片后延迟荧光强度与叶片光合速率的变化表现出很好的相关性。研究结果表明,植物延迟荧光能很好的表征植物叶片DCMU处理后光合速率的变化。