Pretend play and maternal scaffolding : comparisons of toddlers with advanced development, typical development, and hearing impairment

This study used measures of pretend play and maternal scaffolding to explore and compare the early development of deaf children, typically developing children, and children showing advanced intellectual development. Marked differences were found among the groups in both play development and characteristics of mother-child interactions. In particular, children who scored above 130 IQ at four years of age were found, as toddlers, to have demonstrated significantly advanced pretend play. In addition, the mothers of the high IQ children engaged in scaffolding behaviors involving higher stages of pretend transformations, verbal analogies and world links. The findings are discussed in relation to children's learning in Vygotsky's Zone of Proximal Development, as well as possible implications for future research on early gifted development.

Website physical activity interventions : preferences of potential users

Information and communication technologies (particularly websites and e-mail) have the potential to deliver health behavior change programs to large numbers of adults at low cost. Controlled trials using these new media to promote physical activity have produced mixed results. User-centered development methods can assist in understanding the preferences of potential participants for website functions and content, and may lead to more effective programs. Eight focus group discussions were conducted with 40 adults after they had accessed a previously trialed physical activity website. The discussions were audio taped, transcribed and interpreted using a themed analysis method. Four key themes emerged: structure, interactivity, environmental context and content. Preferences were expressed for websites that include simple interactive features, together with information on local community activity opportunities. Particular suggestions included online community notice boards, personalized progress charts, e-mail access to expert advice and access to information on specific local physical activity facilities and services. Website physical activity interventions could usefully include personally relevant interactive and environmentally focused features and services identified through a user-centered development process.

The roses of success

Sometimes success can be detrimental to learning while failure can be good. What appears as a disaster can often lay the foundations for future success.

Usually, educators and students focus on building confidence through successful completion of learning tasks, summarised by Vygotsky’s zone of proximal development. A positive feedback loop is established if learners are successful in mastering new ideas and skills. The problem is if teachers, trainers and instructors never challenge students to the fullest extent of their abilities, as this might also ensure overconfidence, slow progress and boredom.

We should not avoid the risk of failure; science is all about the possible risk of failure. Testable hypotheses have the potential to fail an experimental or computational test; ideas that are not testable are considered to be outside the realm of science. The occasional failure shows the limits and scope of an idea’s validity and enables us to advance scientific ideas.

There is a need to find the balance between challenge that extends students, and over-extension. The former results in greater and true confidence and ability, while the latter leads to catastrophic failure and crises of confidence. Education, like life and like all scientific endeavour is about taking responsible risks safely. When we cultivate the roses of success that grow from the ashes of disaster, we must not forget that roses have thorns, or that the occasional setback or failure is just as important for learning as a succession of successes.

The relevance of Asian development bank: existing in the shadow of the Asian infrastructure investment bank

This paper analyses the potential impact of the China-led Asian Infrastructure Investment Bank (AIIB) on the Japan-USA-led Asian Development Bank (ADB). Given the financial strengths and the technical know-how of the newly formed AIIB there is a question about thefuture role and indeed relevance of the ADB. The questions canvassed in this article refer to ADB’s ability to change and adapt to the new situation, where it is no longer the dominant multi-lateral development bank (MDB) in the Asia-Pacific region. Against this background the discussion turns to issues concerning the geo-political sphere of influence of the ADB andAIIB and analyses the ADB – AIIB geo-political equilibrium in the Asia-Pacific region. Subsequently this paper discusses factors that may impact on ADB’s future relevance.

The limits of human development and the use of energy and natural resources

The development of nations is an unquestionable requirement. A lot of challenges concerning health, education and economy are present. A discussion on these development models has occupied the minds of decision makers in recent years. When energy supply and demand is considered, the situation becomes critical and the crucial question is: how to improve the quality of life of developing countries based on available models of development that are related to the life style of developed countries, for which the necessary use and waste of energy are present? How much energy is essential to humanity for not so as to endangering the survival conditions of future generations? the human development index (HDI) establishes the relationship among energy use, economic growth and social growth. Here it can be seen that 75% of the world population has a significant energy consumption potential. This is a strong reason to consider that the sustainable development concepts on energy policies are strategic to the future of the planet. This paper deals with the importance of seeking alternative development models for human development balance, natural resources conservation and environment through rational energy use concepts. (c) 2004 Elsevier Ltd. All rights reserved.

Characterization of Neural Stem/Progenitor Cells Expressing VEGF and its Receptors in the Subventricular Zone of Newborn Piglet Brain

Neural stem/progenitor cell (NSP) biology and neurogenesis in adult central nervous system (CNS) are important both towards potential future therapeutic applications for CNS repair, and for the fundamental function of the CNS. In the present study, we report the characterization of NSP population from subventricular zone (SVZ) of neonatal piglet brain using in vivo and in vitro systems. We show that the nestin and vimentin-positive neural progenitor cells are present in the SVZ of the lateral ventricles of neonatal piglet brain. In vitro, piglet NSPs proliferated as neurospheres, expressed the typical protein of neural progenitors, nestin and a range of well-established neurodevelopmental markers. Upon dissociation and subculture, piglet NSPs differentiated into neurons and glial cells. Clonal analysis demonstrates that piglet NSPs are multi-potent and retain the capacity to generate both glia and neurons. These cells expressed VEGF, VEGFR1, VEGFR2 and Neuropilin-1 and -2 mRNAs. Real time PCR revealed that SVZ NSPs from newborn piglet expressed total VEGF and all VEGF splice variants. These findings show that piglet NSPs may be helpful to more effectively design growth factor based strategies to enhance endogenous precursor cells for cell transplantation studies potentially leading to the application of this strategy in the nervous system disease and injury.

Spatio-temporal distribution of fish larvae in relation to ontogeny and water quality in the oligohaline zone of a North Brazilian estuary

O padrão de distribuição das larvas de peixes na Baía do Guajará foi estudado através de coletas trimestrais e discutido em relação aos estágios de desenvolvimento dos indivíduos e a exposição dos mesmos aos contaminantes despejados pela Capital do Estado do Pará, Belém. A densidade e a diversidade larval foram baixas com forte dominância dos clupeídeos, engraulídeos e, em menor grau, os cianídeos. O principal período de reprodução foi definido no início do período chuvoso. Larvas de Clupeiformes em pré-flexão e flexão foram encontradas nos pontos de coletas mais afastados da cidade, enquanto aquelas em pós-flexão prevaleceram nas margens da cidade. Por outro lado, os cianídeos em pré-flexão e flexão foram capturados perto dos centros de atividade urbana, enquando aqueles em pós-flexão foram pouco abundantes. É sugerido que a baía se encontra na rota migratória dos cianídeos entre a área de desova e os berçários mais distantes. Apesar das águas no entorno da cidade de Belém mostraram sinais de contaminação, a qualidade ambiental na Baía do Guajará no momento do estudo estava apropriada para a vida das larvas de peixes. Nitrato com pH foram as variáveis que melhor explicaram a distribuição larval.

On the Ecology and Distribution of Echinococcus spp. (Cestoda: Taeniidae), and Characteristics of Their Development in the Intermediate Host. II. Comparative Studies on the Development of Larval E. multilocularis Leuckart, 1863, in the Intermediate Host

This paper reports the results of a comparative study of the development of the larval Echinococcus multilocularis Leuckart, 1863), and associated tissue reaction in naturally and experimentally infected mammals representing 31 species. The histogenesis of the larval cestode was traced in detail in arvicoline rodents of several species, and interspecific differences were defined. In arvicoline rodents, the developing larva exhibited host-specific characteristics within about a month after infection was established. The tissue reaction in Microtus oeconomus was characterized by the production of a large quantity of detritus around the larva, and by the formation of a thick epithelioid zone. In one subspecies, M. oeconomus innuitus, development of the larva was retarded, and the detrital mass was often calcified; in another, M. oeconomus operarius, the detritus rarely became calcified and the larva proliferated more rapidly. In M. pennsylvanicus, the tissue reaction was minimal, and little detritus was present. The characteristics of the tissue reaction in M. montebelli placed it in an intermediate position between the aforementioned species. In Clethrionomys rutilus, a thin epithelioid zone and an outer zone of loose collagenous fibers composed the adventitial layer; exogenous budding was retarded in this vole. A minimal tissue reaction occurred in Lagurus curtatus. In Lemmus spp., larger cysts were characteristic, but areas of small-cystic proliferation were always present. Similar differences in species or subspecies of Citellus and Dicrostonyx were described. Lesions of alveolar bydatid disease in man also were studied. The invasive growth of the larval cestode in the human liver involves a process comparable to small-cystic proliferation in the natural intermediate hosts. Although the later stages of development of the larval cestode are inhibited in man, exogenous proliferation of vesicles continues for the life of the host. The lesion in man was compared with a morphologically similar formation produced by anomalous development of the larval E. granulosus in the bovine liver. The latter is distinguished by the absence of areas of small-cystic proliferation. Non-echinococcal lesions found in the tissues studied, some of which resembled foci caused by the larval E. multilocularis, were briefly discussed.

Weedy Hosts and Prevalence of Potential Leafhopper Vectors (Hemiptera: Cicadellidae) of a Phytoplasma (16SrIX group) Associated With Huanglongbing Symptoms in Citrus Groves

Huanglongbing (HLB) is a severe citrus (Citrus spp.) disease associated with the bacteria genus Candidatus Liberibacter, detected in Brazil in 2004. Another bacterium was found in association with HLB symptoms and characterized as a phytoplasma belonging to the 16SrIX group. The objectives of this study were to identify potential leafhopper vectors of the HLB-associated phytoplasma and their host plants. Leafhoppers were sampled every other week for 12 mo with sticky yellow cards placed at two heights (0.3 and 1.5 m) in the citrus tree canopy and by using a sweep net in the ground vegetation of two sweet orange, Citrus sinensis (L.) Osbeck, groves infected by the HLB-phytoplasma in Sao Paulo state. Faunistic analyses indicated one Agalliinae (Agallia albidula Uhler) and three Deltocephalinae [Balclutha hebe (Kirkaldy), Planicephalus flavicosta (Stal), and Scaphytopius (Convelinus) marginelineatus (Stal)] species, as the most abundant and frequent leafhoppers (Hemiptera: Cicadellidae). Visual observations indicated an association of leafhopper species with some weeds and the influence of weed species composition on leafhopper abundance in low-lying vegetation. S. marginelineatus and P. flavicosta were more frequent on Sida rhombifolia L. and Althernantera tenella Colla, respectively, whereas A. albidula was observed more often on Conyza bonariensis (L.) Cronq. and B. hebe only occurred on grasses. DNA samples of field-collected S. marginelineatus were positive by polymerase chain reaction and sequencing tests for the presence of the HLB-phytoplasma group, indicating it as a potential vector. The association of leafhoppers with their hosts may be used in deciding which management strategies to adopt against weeds and diseases in citrus orchards.

Morphometric analysis of the placenta in the New World mouse Necromys lasiurus (Rodentia, Cricetidae): a comparison of placental development in cricetids and murids

Background: Stereology is an established method to extrapolate three-dimensional quantities from two-dimensional images. It was applied to placentation in the mouse, but not yet for other rodents. Herein, we provide the first study on quantitative placental development in a sigmodontine rodent species with relatively similar gestational time. Placental structure was also compared to the mouse, in order to evaluate similarities and differences in developmental patterns at the end of gestation. Methods: Fetal and placental tissues of Necromys lasiurus were collected and weighed at 3 different stages of gestation (early, mid and late gestation) for placental stereology. The total and relative volumes of placenta and of its main layers were investigated. Volume fractions of labyrinth components were quantified by the One Stop method in 31 placentae collected from different individuals, using the Mercator® software. Data generated at the end of gestation from N. lasiurus placentae were compared to those of Mus musculus domesticus obtained at the same stage. Results: A significant increase in the total absolute volumes of the placenta and its main layers occurred from early to mid-gestation, followed by a reduction near term, with the labyrinth layer becoming the most prominent area. Moreover, at the end of gestation, the total volume of the mouse placenta was significantly increased compared to that of N. lasiurus although the proportions of the labyrinth layer and junctional zones were similar. Analysis of the volume fractions of the components in the labyrinth indicated a significant increase in fetal vessels and sinusoidal giant cells, a decrease in labyrinthine trophoblast whereas the proportion of maternal blood space remained stable in the course of gestation. On the other hand, in the mouse, volume fractions of fetal vessels and sinusoidal giant cells decreased whereas the volume fraction of labyrinthine trophoblast increased compared to N. lasiurus placenta. Conclusions: Placental development differed between N. lasiurus and M. musculus domesticus. In particular, the low placental efficiency in N. lasiurus seemed to induce morphological optimization of fetomaternal exchanges. In conclusion, despite similar structural aspects of placentation in these species, the quantitative dynamics showed important differences.

Significance of the Deformation History within the Hinge Zone of the Pennsylvania Salient, Appalachian Mountains

Two competing models exist for the formation of the Pennsylvania salient, a widely studied area of pronounced curvature in the Appalachian mountain belt. The viability of these models can be tested by compiling and analyzing the patterns of structures within the general hinge zone of the Pennsylvania salient. One end-member model suggests a NW-directed maximum shortening direction and no rotation through time in the culmination. An alternative model requires a two-phase development of the culmination involving NNW-directed maximum shortening overprinted by WNW-directed maximum shortening. Structural analysis at 22 locations throughout the Valley and Ridge and southern Appalachian Plateau Provinces of Pennsylvania are used to constrain orientations of the maximum shortening direction and establish whether these orientations have rotated during progressive deformation in the Pennsylvania salient's hinge. Outcrops of Paleozoic sedimentary rocks contain several orders of folds, conjugate faults, steeply dipping strike-slip faults, joints, conjugate en echelon gash vein arrays, spaced cleavage, and grain-scale finite strain indicators. This suite of structures records a complex deformation history similar to the Bear Valley sequence of progressive deformation. The available structural data from the Juniata culmination do not show a consistent temporal rotation of shortening directions and generally indicate uniform,

An Evaluation of Potential Occupational Exposure to Asbestiform Amphiboles near a Former Vermiculite Mine

Amphibole asbestos (AA) has been detected on the surface of tree bark in forests neighboring an abandoned vermiculite mine near Libby, Montana. In the present study, simulations were performed to assess potential AA exposure associated with United States Department of Agriculture Forest Service (FS) occupational activities. Bark samples were collected prior, and personal breathing zone (PBZ) and Tyvek clothing wipe samples were collected during and immediately after trials that simulated FS activities. Transmission electron microscopy (TEM) analyses revealed AA bark concentrations up to 15 million structures per square centimeter (s/cm2). AA was detected in 25% of the PBZ TEM samples. AA was detected on wipe samples collected from all activities evaluated. This research demonstrates the potential for airborne exposure and transport of AA in the Kootenai National Forest. These findings are especially relevant to those that work in the area and to the general public who may conduct recreational activities.

Small molecule developmental screens reveal the logic and timing of vertebrate development

Much has been learned about vertebrate development by random mutagenesis followed by phenotypic screening and by targeted gene disruption followed by phenotypic analysis in model organisms. Because the timing of many developmental events is critical, it would be useful to have temporal control over modulation of gene function, a luxury frequently not possible with genetic mutants. Here, we demonstrate that small molecules capable of conditional gene product modulation can be identified through developmental screens in zebrafish. We have identified several small molecules that specifically modulate various aspects of vertebrate ontogeny, including development of the central nervous system, the cardiovascular system, the neural crest, and the ear. Several of the small molecules identified allowed us to dissect the logic of melanocyte and otolith development and to identify critical periods for these events. Small molecules identified in this way offer potential to dissect further these and other developmental processes and to identify novel genes involved in vertebrate development.

Abrogation of disease development in plants expressing animal antiapoptotic genes

An emerging topic in plant biology is whether plants display analogous elements of mammalian programmed cell death during development and defense against pathogen attack. In many plant–pathogen interactions, plant cell death occurs in both susceptible and resistant host responses. For example, specific recognition responses in plants trigger formation of the hypersensitive response and activation of host defense mechanisms, resulting in restriction of pathogen growth and disease development. Several studies indicate that cell death during hypersensitive response involves activation of a plant-encoded pathway for cell death. Many susceptible interactions also result in host cell death, although it is not clear how or if the host participates in this response. We have generated transgenic tobacco plants to express animal genes that negatively regulate apoptosis. Plants expressing human Bcl-2 and Bcl-xl, nematode CED-9, or baculovirus Op-IAP transgenes conferred heritable resistance to several necrotrophic fungal pathogens, suggesting that disease development required host–cell death pathways. In addition, the transgenic tobacco plants displayed resistance to a necrogenic virus. Transgenic tobacco harboring Bcl-xl with a loss-of-function mutation did not protect against pathogen challenge. We also show that discrete DNA fragmentation (laddering) occurred in susceptible tobacco during fungal infection, but does not occur in transgenic-resistant plants. Our data indicate that in compatible plant–pathogen interactions apoptosis-like programmed cell death occurs. Further, these animal antiapoptotic genes function in plants and should be useful to delineate resistance pathways. These genes also have the potential to generate effective disease resistance in economically important crops.