Les tecnologies de la informaci?? i la comunicaci?? en la vida quotidiana dels infants i joves

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Temperamental Dimension and Anxiety Problems in a Clinical Sample of Three- to Six-year old Children: A Study of Variables

In the last few years, many researchers have studied the presence of common dimensions of temperament in subjects with symptoms of anxiety. The aim of this study is to examine the association between temperamental dimensions (high negative affect and activity level) and anxiety problems in clinical preschool children. A total of 38 children, ages 3 to 6 years, from the Infant and Adolescent Mental Health Center of Girona and the Center of Diagnosis and Early Attention of Sabadell and Olot were evaluated by parents and psychologists. Their parents completed several screening scales and, subsequently, clinical child psychopathology professionals carried out diagnostic interviews with children from the sample who presented signs of anxiety. Findings showed that children with high levels of negative affect and low activity level have pronounced symptoms of anxiety. However, children with anxiety disorders do not present different temperament styles from their peers without these pathologies

Análisis de los períodos de regresión y transición en el primer año de vida

Aquesta tesi està centrada en l'estudi dels períodes de regressió i transició. A partir dels treballs de van de Rijt-Plooij & Plooij (1992) sobre els períodes de regressió, l'autor analitza les característiques comportamentals d'aquests períodes i la relació que tenen amb els períodes de transició. Els períodes de regressió s'entenen com uns moments del desenvolupament durant els quals els nens perden la homeostasi del seu organisme i manifesten una sèrie de conductes pertorbadores per a la mare. El matrimoni Plooij manté que els períodes de regressió són la manifestació de les reorganitzacions cerebrals que tenen lloc durant el període postnatal, i constitueixen la base de les noves habilitats que el nen va adquirint. Així, doncs, l'augment de l'atenció que la mare dispensa al nen durant els períodes de regressió esdevé una font estimular imprescindible en els processos d'educació i culturalització de l'infant. Per tant, els períodes de regressió estan íntimament relacionats amb els períodes durant els quals apareixen nous comportaments qualitativament diferents dels anteriors, que es manifesten de forma ràpida i sobtada, permetent una certa sistematització del procés evolutiu, per la qual cosa s'han denominat transicions. Van de Rijt-Plooij & Plooij, i també nosaltres, considerem que els períodes de regressió són índexs dels períodes de transició. Per aquesta raó també s'han denominar reprogressions. Tanmateix, els períodes de regressió es poden convertir en una font de conflictes que, en situació de risc, poden degenerar en maltractament infantil i, fins i tot, esdevenir el germen de possibles patogènies. Com veiem, els conceptes de període de regressió i transició es troben a l'encreuament entre la fisiologia, la psicologia i la psicopatologia del desenvolupament i, el seu estudi establiria un pont interdisciplinar que contribuiria a la construcció d'un model biopsicosocial del desenvolupament. Els objectius del nostre estudi varen ser comprovar si els períodes descrits per van de Rijt-Plooij i Plooij (1992) també els podem observar en un grup de nens de la població catalana sense problemes socio-econòmics o sanitaris aparents. Per altra banda, vàrem voler comprovar si els períodes de regressió tenen relació amb els períodes de transició. El disseny d'investigació correspon a un model longitudinal i transversal. Es varen seguir -mitjançant entrevistes, qüestionaris i observacions- vint diades mare-nen durant catorze mesos, repartides en quatre cohorts de cinc diades cada una d'elles. Partint d'uns criteris establerts a priori per a la categorització dels períodes de regressió i transició, vàrem estudiar la temporalitat d'ambdós tipus de períodes. També s'ha aprofundit sobre les característiques comportamentals i dinàmiques dels períodes de regressió. Respecte les dades, els percentatges màxims dels períodes de regressió del nostre grup d'estudi han aparegut a les setmanes: 5, 8, 12-13, 18, 26-27, 35, 43 i 52. La mitjana setmanal de cada període ha sigut de dues setmanes. Les nostres dades confirmen les obtingudes en la investigació de van de Rijt-Plooij & Plooij. Tanmateix, també hem trobat diferències (els períodes de regressió de l'estudi holandès són més llargs i coincideixen més) que ens suggereixen que la cultura podrien estar actuant en la forma de presentació del períodes de regressió. Pel que fa a la relació entre els períodes de regressió i l'emergència de nous comportaments (períodes de transició), els resultats mostren que les freqüències màximes dels períodes de regressió sempre es troben poques setmanes abans de les freqüències màximes dels períodes de transició. Per tant, és possible que els períodes de regressió siguin indicadors dels períodes de transició.

Infants Can Learn Decontextualized Words Before Their First Birthday

Can infants below age 1 year learn words in one context and understand them in another? To investigate this question, two groups of parents trained infants from age 9 months on 8 categories of common objects. A control group received no training. At 12 months, infants in the experimental groups, but not in the control group, showed comprehension of the words in a new context. It appears that infants under 1 year old can learn words in a decontextualized, as distinct from a context-bound, fashion. Perceptual variability within the to-be-learned categories, and the perceptual similarity between training sets and the novel test items, did not appear to affect this learning.

Rapid word learning by 15-month-olds under tightly-controlled conditions

Infants (12 to 17 months) were taught 2 novel words for 2 images of novel objects, by pairing isolated auditory labels with to-be-associated images. Comprehension was tested using a preferential looking task in which the infant was presented with both images together with an isolated auditory label. The auditory label usually, but not always, matched one of the images. Infants looked preferentially at images that matched the auditory stimulus. The experiment controlled within-subjects for both side bias and preference for previously named items. Infants showed learning after 12 presentations of the new words. Evidence is presented that, in certain circumstances, the duration of longest look at a target may be a more robust measure of target preference than overall looking time. The experiment provides support for previous demonstrations of rapid word learning by pre-vocabulary spurt children, and offers some methodological improvements to the preferential looking task.

Early social experience and individual differences in infants' joint attention

Fifty-nine healthy infants were filmed with their mothers and with a researcher at two, four, six and nine months in face-to-face play, and in toy-play at six and nine months. During toy-play at both ages, two indices of joint attention (JA)—infant bids for attention, and percent of time in shared attention—were assessed, along with other behavioural measures. Global ratings were made at all four ages of infants’ and mothers’ interactive style. The mothers varied in psychiatric history (e.g., half had experienced postpartum depression) and socioeconomic status, so their interactive styles were diverse. Variation in nine-month infant JA — with mother and with researcher — was predicted by variation in maternal behaviour and global ratings at six months, but not at two or four months. Concurrent adult behaviour also influenced nine-month JA, independent of infant ratings. Six-month maternal behaviours that positively predicted later JA (some of which remained important at nine months) included teaching, conjoint action on a toy, and global sensitivity. Other behaviours (e.g., entertaining) negatively predicted later JA. Findings are discussed in terms of social-learning and neurobiological accounts of JA emergence.

Productivity of crossbred dairy cows suckling their calves for 12 or 24 weeks post calving

An experiment on restricted suckling of crossbred dairy cows was conducted at the Livestock Research Centre, Tanga in northeast Tanzania. Thirty-six Bos taurus (Holstein Friesian and Jersey) x Bos indicus (East African Zebu) cows were allocated alternately as they calved to suckling their calves for either 12 or 24 weeks after calving. Cows grazed improved pastures and were offered 4 kg concentrate daily. Milking occurred twice daily by hand; calves were allowed to suck residual milk for 30 min following each milking. Calves were also allowed access to grazing and were offered a maximum of I kg concentrate daily to 24 weeks of age. Weaning age had no significant effect on lactation milk yield for human consumption, the mean (SE) yield being 1806 (102.0) L and 1705 (129. 1) L for 12- and 24-week weaning, respectively. Cows from the two treatments suffered similar losses of live weight and body condition score during lactation and neither group had returned to the original body condition score 40 weeks following calving. Post-partum anoestrous intervals were prolonged. Although not significant, cows suckling calves to 24 weeks had a mean interval to first oestrus extended by 38 days compared with cows suckling calves to 12 weeks. The mean (SE) daily live weight gains of the calves to 52 weeks were 263 (14.1) g/day and 230 (18.1) g/day for calves weaned at 12 and 24 weeks, respectively, such that 12-month weights were 119 (5.6) kg and 110 (7.3) kg, respectively. Twelve-week-weaned calves consumed more concentrate (p < 0.05) from 13 to 24 weeks than did 24-week weaned calves. Calculation of residual milk consumption removed by calves from birth to 12 weeks indicated that it accounted for 28% of total yield. No benefits in cow and calf performance and welfare were found to justify prolonging the suckling period to 24 weeks.

Effects of bovine alpha-lactalbumin and casein glycomacropeptide-enriched infant formulae on faecal microbiota in healthy term infants

Objective: Certain milk factors may promote the growth of a host-friendly gastrointestinal microbiota, for example, one that is predominated by bifidobacteria, a perceived healthpromoting genus. This may explain why breast-fed infants experience fewer intestinal infections than their formula-fed counterparts who are believed to have a more diverse microbiota, which is similar to that of adults. The effects of formulas supplemented with 2 such ingredients from bovine milk, a-lactalbumin (alpha-lac) and casein glycomacropeptide (GMP), on gut flora were investigated in this study. Patients and Methods: Six-week-old (4-8 wk), healthy term infants were randomised to a standard infant formula or 1 of 2 test formulae enriched in alpha-Jac with higher or lower GMP until 6 months. Faecal bacteriology was determined by the culture-independent procedure fluorescence in situ hybridisation. Results: There was a large fluctuation of bacterial counts within groups with no statistically significant differences between groups. Although all groups showed a. predominance of bifidobacteria, breast-fed infants had a small temporary increase in counts. Other bacterial levels varied in formula-fed groups, which overall showed an adult-like faecal microflora. Conclusions: It can be speculated that a prebiotic effect for alpha-lac and GMP is achieved only with low starting populations of beneficial microbiota (eg, infants not initially breast-fed.

Freeze-frame: a new infant inhibition task and its relation to frontal cortex tasks during infancy and early childhood

The current study investigated a new, easily administered, visual inhibition task for infants termed the Freeze-Frame task. In the new task, 9-month-olds were encouraged to inhibit looks to peripheral distractors. This was done by briefly freezing a central animated stimulus when infants looked to the distractors. Half of the trials presented an engaging central stimulus, and the other half presented a repetitive central stimulus. Three measures of inhibitory function were derived from the task and compared with performance on a set of frontal cortex tasks administered at 9 and 24 months of age. As expected, infants' ability to learn to selectively inhibit looks to the distractors at 9 months predicted performance at 24 months. However, performance differences in the two Freeze-Frame trial types early in the experiment also turned out to be an important predictor. The results are discussed in terms of the validity of the Freeze-Frame task as an early measure of different components of inhibitory function. (C) 2007 Elsevier Inc. All rights reserved.

Does repairing a cleft lip neonatally have any effect on the longer-term attractiveness of the repair?

Objective: To determine whether attractiveness and success of surgical outcome differ according to the timing of cleft lip repair. Design: Three experiments were conducted: (1) surgeons rated postoperative medical photographs of infants having either neonatal or 3-month lip repair; (2) lay panelists rated the same photographs; (3) lay panelists rated dynamic video displays of the infants made at 12 months. Normal comparison infants were also rated. The order of stimuli was randomized, and panelists were blind to timing of lip repair and the purposes of the study. Setting: Four U.K. regional centers for cleft lip and palate. Participants: Infants with isolated clefts of the lip, with and without palate. Intervention: Early lip repair was conducted at median age 4 days (inter-quartile range [IQR] = 4), and late repair at 104 days (IQR = 57). Main Outcome Measures: Ratings of surgical outcome (Experiment 1 only) and attractiveness (all experiments) on 5-point Likert scales. Results: In Experiment 1 success of surgical outcome was comparable for early and late repair groups (difference = -0.08; 95% confidence interval [CI] = -0.43 to 0.28; p = .66). In all three experiments, attractiveness ratings were comparable for the two groups. Differences were, respectively, 0.10 (95% CI = -2.3 to 0.44, p = .54); -0.11 (95% CI = -0.42 to -0.19, p = .54); and 0.08 (95% CI = -0.11 to 0.28, p =.41). Normal infants were rated more attractive than index infants (difference = 0.38; 95% CI = 0.24 to 0.52; p < .001). Conclusion: Neonatal repair for cleft of the lip confers no advantage over repair at 3 months in terms of perceived infant attractiveness or success of surgical outcome.

The development of perceptual grouping in infants with Williams syndrome

Perceptual grouping by luminance similarity and by proximity was investigated in infants with Williams syndrome (WS) aged between 6 and 36 months (visit 1, N=29). WS infants who were still under 36 months old, 8 months later, repeated the testing procedure (visit 2, N=15). Performance was compared to typically developing (TD) infants aged from 2 to 20 months (N=63). Consistent with the literature, TD participants showed grouping by luminance at the youngest testing age, 2 months. Grouping by proximity had not previous been charted in typical development: this study showed grouping by proximity at 8 months. Infants with WS could group by luminance. Developmental progression of the WS group showed some similarities to typical development, although further investigation is required to further address this in more depth. In contrast, infants with WS were not able to group by proximity. This pattern of emergence and development of grouping abilities is considered in relation to the pattern of grouping abilities observed in adults with WS.

Longitudinal investigation of the faecal microbiota of healthy full-term infants using fluorescence in situ hybridization and denaturing gradient gel electrophoresis.

From birth onwards, the gastrointestinal (GI) tract of infants progressively acquires a complex range of micro-organisms. It is thought that by 2 years of age the GI microbial population has stabilized. Within the developmental period of the infant GI microbiota, weaning is considered to be most critical, as the infant switches from a milk-based diet (breast and/or formula) to a variety of food components. Longitudinal analysis of the biological succession of the infant GI/faecal microbiota is lacking. In this study, faecal samples were obtained regularly from 14 infants from 1 month to 18 months of age. Seven of the infants (including a set of twins) were exclusively breast-fed and seven were exclusively formula-fed prior to weaning, with 175 and 154 faecal samples, respectively, obtained from each group. Diversity and dynamics of the infant faecal microbiota were analysed by using fluorescence in situ hybridization and denaturing gradient gel electrophoresis. Overall, the data demonstrated large inter- and intra-individual differences in the faecal microbiological profiles during the study period. However, the infant faecal microbiota merged with time towards a climax community within and between feeding groups. Data from the twins showed the highest degree of similarity both quantitatively and qualitatively. Inter-individual variation was evident within the infant faecal microbiota and its development, even within exclusively formula-fed infants receiving the same diet. These data can be of help to future clinical trials (e.g. targeted weaning products) to organize protocols and obtain a more accurate outline of the changes and dynamics of the infant GI microbiota.

The role of fimbriae and flagella in the colonization, invasion and persistence of Escherichia coli O78 : K80 in the day-old-chick model

To understand the role of flagella and fimbriae of Escherichia coli O78:K80 in avian colibacillosis, day-old chicks were dosed orally with defined afimbriate and or aflagellate mutants and colonization, invasion and persistence compared with that of the wild-type. In an invasion model, chicks were dosed with 1 x 10(5) c.f.u. of a single strain and mutants defective for type 1 fimbriae, curli fimbriae or flagella colonized livers by 24 h although the numbers of bacteria present were significantly less than the wild-type, Mutants colonized between 50 and 75 % of spleens whereas the wild-type colonized 100 % of spleens. Additionally, the numbers of mutant bacteria in colonized spleens were significantly less than the wild-type. Surprisingly, mutants defective for the elaboration of more than one appendage were no more attenuated than single mutants. In a persistence model, chicks were dosed with 1 x 10(2) c.f.u. of a single strain and mutants defective for type 1 or curli or flagella or any combination thereof persisted as assessed by cloacal swabbing for 5 weeks of the experiment less well than the wild-type. In an additional persistence model, chicks were dosed with 5 x 10(2) c.f.u. of each of wild-type and one mutant together. All mutants were significantly less persistent than the wild-type (P < 0.001) and one mutant which lacked type 1, curli and flagella, was eliminated within 2 weeks. Analysis of the trends of elimination indicated that flagella contributed to persistence more than curli, which contributed more than type 1 fimbriae. Here was evidence for a major role in colonization, invasion and persistence played by type 1, curli and flagella.

Colonization of 8-week-old conventionally reared goats by Escherichia coli O157:H7 after oral inoculation

Enterohaemorrhagic Escherichia coli O157 : H7 infections of man have been associated with consumption of unpasteurized goat's milk and direct contact with kid goats on petting farms, yet little is known about colonization of goats with this organism. To assess the contribution of flagella and intimin of E coli O157 : H7 in colonization of the goat, 8-week-old conventionally reared goats were inoculated orally in separate experiments with 1 X 10(10) c.f.u. of a non-verotoxigenic strain of E coli O157: H7 (strain NCTC 12900 Nal(r)), an aflagellate derivative (DMB1) and an intimin-deficient derivative (DMB2). At 24 In after inoculation, the three E coli O157 : H7 strains were shed at approximately 5 X 1 04 c.f.u. (g faeces)(-1) from all animals. Significantly fewer intimin-deficient bacteria were shed only on days 2 (P = 0(.)003) and 4 (P = 0(.)014), whereas from day 7 to 29 there were no differences. Tissues from three animals inoculated with wild-type E coli O157 : H7 strain NCTC 12900 Nalr were sampled at 24,48 and 96 In after inoculation and the organism was cultured from the large intestine of all three animals and from the duodenum and ileum of the animal examined at 96 h. Tissues were examined histologically but attaching-effacing (AE) lesions were not observed at any intestinal site of the animals examined at 24 or 48 In. However, the animal examined at 96 h, which had uniquely shed approximately 1 x 10(7) E coli O157: H7 (g faeces)(-1) for the preceding 3 days, showed a heavy, diffuse infection with cryptosporidia. and abundant, multifocal AE lesions in the distal colon, rectum and at the recto-anal junction. These AE lesions were confirmed by immunohistochemistry to be associated with E coli O157: H7.