The use of the coefficient of agreement and likelihood ratio test to examine the development of the tympanic plate using a known-age sample of fetal and infant skeletons

Previous attempts to use the development of the tympanic plate as an aging standard for fetal and infant cranial remains have either produced only a developmental sequence (Anderson, 1960), or a sequence for which age has been estimated using another independent aging standard (Weaver, 1979). Following an evaluation of the first three stages of development of the tympanic plate using a known-age sample of fetal and infant skeletal remains, a simple test of inter-observer agreement, Cohen's coefficient of agreement (Cohen, 1960), is demonstrated using the developmental stages.     

Age and sex diagnosis of the skeleton of immature individuals

In connection with increasing theory-bound investigations in prehistoric anthropology age and sex diagnosis of children's skeletons is gaining importance. Developmental stages of the tympanic plate are introduced as an additional criterion for ageing infants. Discriminant functions derived from ilium and femur measurements allow preliminary access towards a metric sexual diagnosis of fetal and neonate individuals.     

Adaptive molecular evolution of virulence genes of avian influenza - A virus subtype H5N1: An analysis of host radiation

The phenomenon of host radiation is strongly influenced by the rates of mutation of their virulence genes. We have studied the molecular evolution of virulence genes (HA, NS, PB2) of the Avian Influenza Virus H5N1 from avian to human hosts. We used a site-specific comparison of synonymous (silent) and non-synonymous (amino acid altering) nucleotide substitutions for the three chosen genes in parasite populations from different hosts. Analyses were made using Maximum Likelihood (ML) genealogies for the null and alternate hypothesis based on differential gamma distribution rates. The null hypothesis had a higher rate of substitution and was found to be more suitable for all the studied genes by Likelihood Ratio Test (LRT). The study showed the NS gene to be having the fastest rate of evolution.     

Application of Artificial Bee Colony Algorithm to Maximum Likelihood DOA Estimation

Maximum Likelihood (ML) method has an excellent performance for Direction-Of-Arrival (DOA) estimation, but a multidimensional nonlinear solution search is required which complicates the computation and prevents the method from practical use. To reduce the high computational burden of ML method and make it more suitable to engineering applications, we apply the Artificial Bee Colony (ABC) algorithm to maximize the likelihood function for DOA estimation. As a recently proposed bio-inspired computing algorithm, ABC algorithm is originally used to optimize multivariable functions by imitating the behavior of bee colony finding excellent nectar sources in the nature environment. It offers an excellent alternative to the conventional methods in ML-DOA estimation. The performance of ABC-based ML and other popular meta-heuristic-based ML methods for DOA estimation are compared for various scenarios of convergence, Signal-to-Noise Ratio (SNR), and number of iterations. The computation loads of ABC-based ML and the conventional ML methods for DOA estimation are also investigated. Simulation results demonstrate that the proposed ABC based method is more efficient in computation and statistical performance than other ML-based DOA estimation methods.     

The local-clock permutation test: a simple test to compare rates of molecular evolution on phylogenetic trees

Rates of molecular evolution vary substantially between lineages, and a growing effort is directed at uncovering the causes and consequences of this variation. Comparing local-clocks (rates of molecular evolution estimated from different sets of branches of a phylogenetic tree) is a common tool in this research effort. Here, I show that a commonly used test (the Likelihood Ratio Test, LRT) will not be statistically valid for comparing local-clocks in most cases. Instead, I propose the local-clock permutation test (LCPT), a simple test that can be used to test the significance of differences between local-clocks. The LCPT could also be used to test for differences between any parameter that can be assigned to individual branches on a phylogenetic tree. Using simulated data, I show that the LCPT has good power to detect differences between local-clocks.     

Age estimation in bowhead whales using tympanic bulla histology and baleen isotopes

Tympanic bullae and baleen plates from bowhead whales of the Western Arctic population were examined. Growth layer groups (GLGs) in the involucrum of the tympanic bone were used to estimate age of the whales, and compared to stable isotope signatures along transects of baleen plates and the involucrum. The involucrum of the tympanic bone consists of three regions that form in utero, during nursing in the first year, and during the first decades of life, respectively. Life history events, such as annual migration, are recorded in the bowhead tympanic bulla. It is likely that bone growth in the bowhead tympanic occurs during periods of high food intake, while slow or arrested growth occurs during periods of low food intake. Comparisons between numbers of GLGs in the tympanic, number of isotopic oscillations in a baleen plate, length of the baleen plate, and total whale length show correlation coefficients as high as 0.97. The tympanic GLG method is particularly useful for estimating the age of whales up to 20 yr old.     

Incidence of congenital hypothyroidism: retrospective study of neonatal laboratory screening versus clinical symptoms as indicators leading to diagnosis.

Filter paper blood samples taken routinely from 100 239 newborn infants were radioimmunoassayed five years later for plasma thyrotrophin concentrations. In 32 cases (0.03%) these were found to be raised. Thirty one of these children were traced and subjected to follow up examination by a paediatrician and a psychologist. Of the 31 children, 15 were found to have been receiving treatment for congenital hypothyroidism since a median of 5 months of age (diagnosed group). Of the 16 others, seven children were found to have raised serum thyrotrophin concentrations and were classified as hypothyroid (undiagnosed group). The remaining nine children were euthyroid. Children in the diagnosed group had a mean Griffiths developmental quotient of 87 (control value 103; p less than 0.01), and five out of 13 showed impaired neurological development. Of the remainder, those in the undiagnosed group had a mean developmental quotient of 100 and those in the euthyroid group a mean developmental quotient of 107. In this study achieving a detection rate of congenital hypothyroidism of one in 3000 in a neonatal screening programme resulted in overdiagnosis of about a quarter of patients considered to have true positive findings. This was outweighed, however, by the early identification of all infants with the disease.     

Sequential sampling plans to Orthezia praelonga Douglas (Hemiptera: Sternorrhyncha, Ortheziidae) in citrus

The sequential sampling is characterized by using samples of variable sizes, and has the advantage of reducing sampling time and costs if compared to fixed-size sampling. To introduce an adequate management for orthezia, sequential sampling plans were developed for orchards under low and high infestation. Data were collected in Mat?o, SP, in commercial stands of the orange variety 'Pêra Rio', at five, nine and 15 years of age. Twenty samplings were performed in the whole area of each stand by observing the presence or absence of scales on plants, being plots comprised of ten plants. After observing that in all of the three stands the scale population was distributed according to the contagious model, fitting the Negative Binomial Distribution in most samplings, two sequential sampling plans were constructed according to the Sequential Likelihood Ratio Test (SLRT). To construct these plans an economic threshold of 2% was adopted and the type I and II error probabilities were fixed in alpha = beta = 0.10. Results showed that the maximum numbers of samples expected to determine control need were 172 and 76 samples for stands with low and high infestation, respectively.     

Biological age in children who practise swimming.

In the estimation of the developmental regularity among children it is important to know the relation between the developmental and the calendar age. It is particularly important in the estimation of the level of development among children with an increased level of guided motor activity. It takes place, for instance, in the case of children practising swimming. In auxology there are many morphological, physiological and motor features which are regarded as the measure of the developmental age. For several years researches have been conducted on the EMN index as the determinant of the biological age. The EMN index shows continuous changes during ontogeny, proves the existence of stages in the developmental age and is also considerably correlated with the calendar age. This is an ecosensitive factor. The EMN index differentiates individuals from another as well as groups isolated with regard to the effect of the environmental factors, for instance, the different levels of motor activity. The aim of this investigation is to estimate the standard of biological maturity (the body height and mass, the EMN index) among children, who went through a guided swimming training. Morphological features are most often used as the measures of development. However, they can become unreliable when they themselves establish the criterion of selection to a sports discipline or when some ranges of values are optimal on some given standards. The EMN index is not burdened with these features. The children who go through training show the higher level of the EMN index values than the children who do not go. The effect of this is the fact that young swimmers are biologically older than their peers. However, the shape of the curve of development of the EMN index in swimmers goes at a different level depending on the seniority of training.     

A Novel Experimental and Analytical Approach to the Multimodal Neural Decoding of Intent During Social Interaction in Freely-behaving Human Infants

Understanding typical and atypical development remains one of the fundamental questions in developmental human neuroscience. Traditionally, experimental paradigms and analysis tools have been limited to constrained laboratory tasks and contexts due to technical limitations imposed by the available set of measuring and analysis techniques and the age of the subjects. These limitations severely limit the study of developmental neural dynamics and associated neural networks engaged in cognition, perception and action in infants performing “in action and in context”. This protocol presents a novel approach to study infants and young children as they freely organize their own behavior, and its consequences in a complex, partly unpredictable and highly dynamic environment. The proposed methodology integrates synchronized high-density active scalp electroencephalography (EEG), inertial measurement units (IMUs), video recording and behavioral analysis to capture brain activity and movement non-invasively in freely-behaving infants. This setup allows for the study of neural network dynamics in the developing brain, in action and context, as these networks are recruited during goal-oriented, exploration and social interaction tasks.     

Twice-daily antibiotics in the treatment of acute otitis media: trimethoprim-sulfamethoxazole versus amoxicillin-clavulanate.

Twice-daily trimethoprim-sulfamethoxazole has been shown to be effective in the treatment of acute otitis media except that caused by group A beta-streptococci. Amoxicillin-clavulanate potassium is effective in vitro against all bacterial pathogens causing acute otitis media and has been reported to be effective when given twice daily for urinary tract infections, acute otitis media and respiratory tract infections. To determine whether the in-vitro efficacy of amoxicillin-clavulanate carries over clinically, we conducted a prospective randomized double-blind trial in 219 children presenting at a pediatric walk-in clinic. Diagnosis and follow-up assessments were made by means of examination of the tympanic membrane and acoustic otoscopy. Of the 219 children 202 (101 in either group) were assessed by a specially trained nurse at a follow-up visit 12 to 16 (mean 14) days after treatment was begun. Cure was defined as absence of symptoms and normal results of both visual inspection of the tympanic membrane and acoustic reflectometry; improvement was defined as absence of symptoms and either normal appearance of the tympanic membrane or normal results of acoustic reflectometry; treatment failure was defined as abnormal appearance of the tympanic membrane along with an acoustic reflectometry reading of 5 units or more. There were no differences in age (mean 60 months), sex or proportion of subjects with unilateral versus bilateral disease between the two groups. The combined rate of cure an improvement was significantly higher with trimethoprim-sulfamethoxazole (93%) than with amoxicillin-clavulanate (82%) (p = 0.03). The rate of compliance (more than 80% of the drug taken) did not differ significantly between the two groups. Gastrointestinal side effects were more common with amoxicillin-clavulanate (p less than 0.0001). Our results suggest that for acute otitis media twice-daily trimethoprim-sulfamethoxazole is more effective clinically and produces fewer side effects than twice-daily amoxicillin-clavulanate.     

Sex differences in interest in infants across the lifespan

This study investigated sex differences in interest in infants among children, adolescents, young adults, and older individuals. Interest in infants was assessed with responses to images depicting animal and human infants versus adults, and with verbal responses to questionnaires. Clear sex differences, irrespective of age, emerged in all visual and verbal tests, with females being more interested in infants than males. Male interest in infants remained fairly stable across the four age groups, whereas female interest in infants was highest in childhood and adolescence and declined thereafter, particularly for the responses to visual stimuli. The observed developmental changes in female interest in infants are consistent with the hypothesis that they represent a biological adaptation for parenting. This study was supported by NIH grants R01-MH57249, R01-MH62577, and K02-MH63097. Dario Maestripieri, Ph.D., is an assistant professor of Human Development and Evolutionary Biology at the University of Chicago. He has broad research interests in behavior, development, and evolution, and conducted research on primate parenting and development at the University of Cambridge and at the Yerkes Regional Primate Research Center before moving to Chicago. Suzanne Pelka is a graduate student in Human Development at the University of Chicago.     

Functional near-infrared spectroscopy studies in children

Psychosomatic and developmental behavioral medicine in pediatrics has been the subject of significant recent attention, with infants, school-age children, and adolescents frequently presenting with psychosomatic, behavioral, and psychiatric symptoms. These may be a consequence of insecurity of attachment, reduced self-confidence, and peer -relationship conflicts during their developmental stages. Developmental cognitive neuroscience has revealed significant associations between specific brain lesions and particular cognitive dysfunctions. Thus, identifying the biological deficits underlying such cognitive dysfunction may provide new insights into therapeutic prospects for the management of those symptoms in children. Recent advances in noninvasive neuroimaging techniques, and especially functional near-infrared spectroscopy (NIRS), have contributed significant findings to the field of developmental cognitive neuroscience in pediatrics. We present here a comprehensive review of functional NIRS studies of children who have developed normally and of children with psychosomatic and behavioral disorders.     

Multivariate correlation estimator for inferring functional relationships from replicated genome-wide data

Estimating pairwise correlation from replicated genome-scale (a.k.a. OMICS) data is fundamental to cluster functionally relevant biomolecules to a cellular pathway. The popular Pearson correlation coefficient estimates bivariate correlation by averaging over replicates. It is not completely satisfactory since it introduces strong bias while reducing variance. We propose a new multivariate correlation estimator that models all replicates as independent and identically distributed (i.i.d.) samples from the multivariate normal distribution. We derive the estimator by maximizing the likelihood function. For small sample data, we provide a resampling-based statistical inference procedure, and for moderate to large sample data, we provide an asymptotic statistical inference procedure based on the Likelihood Ratio Test (LRT). We demonstrate advantages of the new multivariate correlation estimator over Pearson bivariate correlation estimator using simulations and real-world data analysis examples. AVAILABILITY: The estimator and statistical inference procedures have been implemented in an R package 'CORREP' that is available from CRAN [http://cran.r-project.org] and Bioconductor [http://www.bioconductor.org/]. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.     

High density of endothelin binding sites in the hearts of infants and children

Endothelin (ET)-1 peripheral levels are high in children with respect to values of adults, but its pathophysiological significance remains to be established. In these conditions the interaction of ET-1 with its receptors may constitute a clue to the understanding of ET-1 function. Because a direct determination of ET binding sites in the heart of children is lacking, in this study we have attempted an assessment of the ET receptor status in cardiac tissue of infants (<1 year; 0.39 +/- 0.26 (SD) years, n=6) and children (1-14 years; 6.3 +/- 4.9 years, n=7) as well as an evaluation of the receptor modulation as a function of age, associated to the observed decrease of plasma ET levels between infants and children. ET-1 binding sites have also been evaluated in atrium and ventricle membranes of adult subjects recipient of cardiac transplantation (CHF) and of post-mortem cardiac specimens (autopsy) of non cardiac patients. Considering all the pediatric patients (infants +/- children) studied, an affinity constant (Kd) value of 38.2 +/- 6.1 (SEM) pM and a density (Bmax) value of 166.2 +/- 11.6 fmol/mg protein has been obtained for atrium. Similar values have been found in the ventricle. These values are significantly higher with respect to those obtained in adults: for atrial membranes, Kd = 22.2 +/- 9.7 and 11.6 +/- 1.8 pM; Bmax = 58.4 +/- 22.8 and 42.1 +/- 8.9 fmol/mg protein, respectively in explanted hearts and in post mortem specimens. No significant differences have been found in the binding parameters between infants and children, while, considering our results as a whole, a significant inverse correlation between Bmax and subject age (p<0.001) is suggested. The ET-A/ET-B ratio, evaluated by competition experiments with the specific ET-A antagonist BQ-123, was about 70:30 in pediatric patients, in both atrium and ventricle, without any difference between infants and children. Similar values for ET-A/ET-B ratio in adult CHF patients, in contrast to a reduction (significant only in ventricle) of the percent of ET-A subtype in autopsy, has been found. This is the first study concerning a direct evaluation of ET receptor status in children's hearts; the higher density of binding sites, associated to the elevation of plasma levels, could suggest a enhanced biological function of ET in children.     

A Modification of Stone's Test for Trend for Binary Outcome

Stone (1988) suggested the “first isotonic regression estimator” as a tool for drawing inferences on possibly increased cancer case counts among several subregions around a putative source. He assumed the case counts to be Poisson distributed and therefore introduced a rare disease assumption into his approach. However, when analyzing cross sectional data one would rather refer to prevalence estimates among these subregions around a point risk source (for example the origin of chemical fallout). Therefore we applied antitonic regression estimation in Binomial distributions to derive a test statistic and a p value to test for a possible trend in the observed prevalence data around the putative source. The computation of this p value will be illustrated as well as severe difficulties concerning its interpretation. Further the Maximum Likelihood Ratio approach will be used to derive an alternative test statistic.     

Delayed Early Primary Visual Pathway Development in Premature Infants: High Density Electrophysiological Evidence

In the past decades, multiple studies have been interested in developmental patterns of the visual system in healthy infants. During the first year of life, differential maturational changes have been observed between the Magnocellular (P) and the Parvocellular (P) visual pathways. However, few studies investigated P and M system development in infants born prematurely. The aim of the present study was to characterize P and M system maturational differences between healthy preterm and fullterm infants through a critical period of visual maturation: the first year of life. Using a cross-sectional design, high-density electroencephalogram (EEG) was recorded in 31 healthy preterms and 41 fullterm infants of 3, 6, or 12 months (corrected age for premature babies). Three visual stimulations varying in contrast and spatial frequency were presented to stimulate preferentially the M pathway, the P pathway, or both systems simultaneously during EEG recordings. Results from early visual evoked potentials in response to the stimulation that activates simultaneously both systems revealed longer N1 latencies and smaller P1 amplitudes in preterm infants compared to fullterms. Moreover, preterms showed longer N1 and P1 latencies in response to stimuli assessing the M pathway at 3 months. No differences between preterms and fullterms were found when using the preferential P system stimulation. In order to identify the cerebral generator of each visual response, distributed source analyses were computed in 12-month-old infants using LORETA. Source analysis demonstrated an activation of the parietal dorsal region in fullterm infants, in response to the preferential M pathway, which was not seen in the preterms. Overall, these findings suggest that the Magnocellular pathway development is affected in premature infants. Although our VEP results suggest that premature children overcome, at least partially, the visual developmental delay with time, source analyses reveal abnormal brain activation of the Magnocellular pathway at 12 months of age.     

Causes of infant mortality in the Middle Ages revealed by chemical and palaeopathological analyses of skeletal remains

In most prehistoric and historic populations, mortality of small infants is very high. Causes of death are mainly discussed in analogy to the situation in modern preindustrial societies. The children are at high risk to fall ill or even die especially in times of weaning. Trace element analysis of the skeletal remains of small infants excavated in Schleswig (northern Germany, 11th/12th century AD) led to the estimation of weaning age as well as to the reconstruction of a stepwise substitution of mothers' milk by other food items. Subsequent palaeopathological analysis confirmed high mortality in this age-group. Thus, causes of death of small infants in a medieval town can be outlined.     

Evidence for developmental programming of cerebral laterality in humans

Adverse fetal environments are associated with depression, reduced cognitive ability and increased stress responsiveness in later life, but underlying mechanisms are unknown. Environmental pressures on the fetus, resulting from variations in placental function and maternal nutrition, health and stress might alter neurodevelopment, promoting the development of some brain regions over others. As asymmetry of cerebral activity, with greater right hemisphere activity, has been associated with psychopathology, we hypothesized that regional specialization during fetal life might be reflected persistently in the relative activity of the cerebral hemispheres. We tested this hypothesis in 140 healthy 8–9 year-old children, using tympanic membrane temperature to assess relative blood flow to the cerebral hemispheres at rest and following psychosocial stress (Trier Social Stress Test for Children). Their birth weight and placental weight had already been measured when their mothers took part in a previous study of pregnancy outcomes. We found that children who had a smaller weight at birth had evidence of greater blood flow to the right hemisphere than to the left hemisphere (r = −.09, P = .29 at rest; r = −.18, P = .04 following stress). This finding was strengthened if the children had a relatively low birth weight for their placental weight (r = −.17, P = .05 at rest; r = −.31, P = .0005 following stress). Our findings suggest that lateralization of cerebral activity is influenced persistently by early developmental experiences, with possible consequences for long-term neurocognitive function.     

Actigraphic Monitoring of the Activity-Rest Behavior of Preterm and Full-Term Infants at 20 Months of Age

Differences in the activity-rest behavior of preterm and full-term infants provide an important contribution to the analysis of the ontogeny of circadian rhythms. In this study, we recorded the activity-rest behavior of 17 preterm and 8 full-term infants at the approximate age of 20 months over an average of 10 days by means of actigraphic monitoring (Actiwatch®, Cambridge Neurotechnology Ltd.). At the same time, the parents of the infants kept a daily diary. The activity-rest rhythm, the nighttime sleep duration, the daytime rest duration, as well as the sleep quality of the infants were analyzed. Preterm and full-term infants at the age of 20 months show a circadian rhythm with a period length between 23 h 32 min (23:32 h) and 24 h 23 min (24:23 h). It can be concluded that the preterm and full-term infants all reached a vital developmental step by showing the dominant circadian rhythm in the spectrum. The daytime rest duration of preterm infants is significantly shorter than that of full-term infants. The sleep quality of preterm infants is significantly lower than that of full-term infants, which means that the preterm infants have a larger percentage of less restful nighttime sleep. In other studies preterm infants show an over-proportional frequency of attention deficit hyperactivity disorder (ADHD). For this reason, future analyses should reveal whether or not actigraphic monitoring is a suitable means for an early identification of activity-rest behavior in children who may develop ADHD.