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We explored whether supported (SJE) or coordinated joint engagement (CJE) between mothers recruited from the community and their 24-month-old children who were slow-to-talk at 18 months old were associated with child language scores at ages 24, 36, and 48 months (n = 197). We further explored whether SJE or CJE modified the concurrent positive associations between maternal responsive behaviours and language scores. Previous research has shown that SJE, maternal expansions, imitations, and responsive questions were associated with better language scores. Our main finding was that SJE but not CJE was consistently positively associated with 24- and 36-month-old expressive and receptive language scores, but not with 48-month-old language scores. SJE modified how expansions and imitations, but not responsive questions, were associated with language scores; the associations were evident in all but the highest levels of SJE. Further research is necessary to test these findings in other samples before clinical recommendations can be made.
Avifaunal remains from archaeological sites have a largely unrecognized explanatory potential. Archaeological, ethnohistoric, and ethnographic records have shown that, especially in Mesoamerica, birds and their products have served a wide range of utilitarian, decorative, and symbolic purposes. Despite their ability to inform research on many aspects of prehistoric life, avifaunal remains from archaeological contexts remain under-studied. This paper demonstrates how a holistic approach to their analysis—one that explores several types of human-bird interaction—can move beyond studies of subsistence. A previously reported and newly updated avifaunal collection was reanalyzed to shed light on the relationship between the many uses of birds and the establishment of hereditary inequality at Paso de la Amada, an Early Formative period ceremonial center on the Pacific coast of Chiapas, Mexico. Results indicate that Early Formative people used birds as a source of food, feathers, and bone, and that the ritual use of birds was an important component of status display. Even at this early date, birds were symbolically valuable and played a role in ritual performance, suggesting that their later significance in Mesoamerican ritual, religion, and iconography has an antecedent beginning no later than 1700 BC.
Mealybug is an important pest of cassava plant in Thailand and tropical countries, leading to severe damage of crop yield. One of the most successful controls of mealybug spread is using its natural enemies such as green lacewings, where the development of mathematical models forecasting mealybug population dynamics improves implementation of biological control. In this work, the Sharpe–Lotka–McKendrick equation is extended and combined with an integro-differential equation to study population dynamics of mealybugs (prey) and released green lacewings (predator). Here, an age-dependent formula is employed for mealybug population. The solutions and the stability of the system are considered. The steady age distributions and their bifurcation diagrams are presented. Finally, the threshold of the rate of released green lacewings for mealybug extermination is investigated.
Samples collected from four snow pits at Eclipse Icefield, Yukon, Canada, were analyzed for stable isotopes and major ions to assess seasonal and spatial variability in snow chemistry. Accumulation since the end of the 2001 summer season over the 0.1 km2 area sampled ranges from 0.77 to 1.16mw.e. Snow-pit stratigraphy and chemical records demonstrate that the low accumulation at pit 3 is due to an under-representation of winter snow accumulation at that site. For all major-ion species, chemical concentrations are independent of snow accumulation rate. Seasonal variations are evident in the major-ion records and can be divided between sea-salt species (Na+, Cl−) that peak in late fall to winter, and dust (Ca2+, Mg2+, K+) and other species (NH4+, NO3−, SO42–, C2O22–) that peak in late spring to summer. The signal common to all four snow pits identified by empirical orthogonal function analysis ranges from 49% of the total variance for Na+ and Cl− to as high as 80% of the total variance for SO42–. There is greater spatial variability in species associated with coarse-mode particles (Na+, Cl−, Ca2+, Mg2+) than in species present mainly in accumulation-mode aerosols (SO42–, NH4+) or in the gas phase (NO3−).
Oxygen isotopic and soluble ionic measurements made on snow-pit (2 m depth) and firn-core (12.4 m depth) samples recovered from the accumulation zone (5100 m) of Inilchek glacier (43° N, 79° E) provide information on recent (1992–98) climatic and environmental conditions in the central Tien Shan region of central Asia. The combined 14.4 m snow-pit/firn-core profile lies within the firn zone, and contains only one observed melt feature (10 m temperature = −12°C). Although some post-depositional attenuation of the sub-seasonal δ18O record is possible, annual cycles are apparent throughout the isotope profile. We therefore use the preserved δ18O record to establish a depth/age scale for the core. Mean δ18O values for the entire core and for summer periods are consistent with δ18O/temperature observations, and suggest the δ18O record provides a means to reconstruct past changes in summer surface temperature at the site. Major-ion (Na+, K+, Mg2+, Ca2+, NH4+, Cl−, NO3−, SO42−) data from the core demonstrate the dominant influence of dust deposition on the soluble chemistry at the site, and indicate significant interannual variability in atmospheric-dust loading during the 1990s. Anthropogenic impacts on NH4+ concentrations are observed at the site, and suggest a summer increase in atmospheric NH4+ that may be related to regional agricultural (nitrogen-rich fertilizer use) activities.
Sexuality is still a taboo in Middle Eastern countries, and Lebanon is no exception. This study’s objective was to evaluate attitudes towards sexuality and its practice among university students in Lebanon and assess their respective correlates. The cross-sectional study was carried out among students selected from seventeen universities across Lebanon. The participants received a self-administered standardized questionnaire that assessed their attitudes towards sexuality. It included questions on socio-demographic factors, risk-taking, risky behaviours and sexuality-related questions. Among 3384 students, 2700 (79.8%) answered the questions on sexuality. Around 15% had engaged in sexual activity, while 20% were regularly sexually active. Among males, 34.8% had never had sexual activity, 29.9% had tried it and 35.3% were regularly sexually active. Among females the results were respectively 85.1%, 5.3% and 9.6% (p<0.001). Only 36% regularly used condoms during their relationships. A liberal attitude towards sex, male sex, motives for risky behaviours, current cigarette smoking and problematic alcohol consumption were associated with sexual activity. Realizing that risky behaviours are dangerous, health concerns related to sexual relationships and a liberal attitude towards sex were associated with regular condom use. However, being bothered by condoms and female sex were inversely associated with condom use. Finally, participants who had motives for, and those who felt excited about risky behaviours, and those reporting current cigarette and waterpipe smoking and problematic alcohol consumption (β=0.600; p=0.002) embraced a more liberal attitude towards sex. Conversely, females (β=−7.58; p<0.001) and individuals who considered risky behaviours as dangerous reported an unfavourable attitude towards sexuality. A substantial proportion of Lebanese university students have regular sexual activity, but a low percentage use condoms for protection. Interventions are required among males in particular in view of these attitude and behavioural changes towards sexuality.
This report presents the preliminary results of the final season of the UNESCO Libyan Valleys Survey, that took place in October 1989. The fieldwork was divided in two parts. The first part of the work concentrated on the settlements in the Wadi Buzra, a northern tributary of the Wadi Sofeggin, especially at Souk el Awty. The major monument here consists of a substantial church (published elsewhere by D. A. Welsby in this volume), which was investigated by architectural survey and limited excavation, as were the surrounding late Romano-Libyan farms. The modern name of the settlement suggests that it may have been an important centre in Islamic as well as the Romano-Libyan periods, but the excavation did not obtain conclusive chronological evidence. The second part of the fieldwork was in the Wadi Umm el-Kharab, a southern tributary of the Sofeggin. Here, the team carried out a detailed study of a series of fortified farms of the later Romano-Libyan period, to compare with the open farm of the earlier Romano-Libyan period in Wadi el Amud previously studied by the project. An analysis of the constructional details of the major farms was integrated with excavations to recover stratified dating evidence from within the farms and faunal and botanical evidence from associated middens, and with a survey of the water-control systems of walls down the length of the wadi. The study indicates that the wadi was settled by people living in open farms and nucleated settlements in the first four centuries AD, but that by the fifth and sixth centuries AD these were replaced by fortified farms. There is evidence that the occupants of the fortified farms cultivated the wadi within an integrated economic system characterised by centralised food storage, rather than as independent units.
The principles embodied by the Developmental Origins of Health and Disease (DOHaD) view of ‘life history’ trajectory are increasingly underpinned by biological data arising from molecular-based epigenomic and transcriptomic studies. Although a number of ‘omic’ platforms are now routinely and widely used in biology and medicine, data generation is frequently confounded by a frequency distribution in the measurement error (an inherent feature of the chemistry and physics of the measurement process), which adversely affect the accuracy of estimation and thus, the inference of relationships to other biological measures such as phenotype. Based on empirical derived data, we have previously derived a probability density function to capture such errors and thus improve the confidence of estimation and inference based on such data. Here we use published open source data sets to calculate parameter values relevant to the most widely used epigenomic and transcriptomic technologies Then by using our own data sets, we illustrate the benefits of this approach by specific application, to measurement of DNA methylation in this instance, in cases where levels of methylation at specific genomic sites represents either (1) a response variable or (2) an independent variable. Further, we extend this formulation to consideration of the ‘bivariate’ case, in which the co-dependency of methylation levels at two distinct genomic sites is tested for biological significance. These tools not only allow greater accuracy of measurement and improved confidence of functional inference, but in the case of epigenomic data at least, also reveal otherwise cryptic information.
The authors show that the principal correlates of feasting in Viking Age Iceland were beef and barley, while feasting itself is here the primary instrument of social action. Documentary references, ethnographic analogies, archaeological excavation and biological analyses are woven together to present an exemplary procedure for the recognition of feasting more widely.
This thesis investigated learning and other outcomes in participants, particularly students (9–11 years), as a result of their involvement in an education for sustainability (EfS) co-design and build project at their primary school in New Zealand, within the Enviroschools Programme. The research focused on four areas that distinguished the project: sustainability learning as the issue, participatory practice as the method, design as the process, and community partnerships as the sphere of involvement. Each of these was considered in terms of its influence on learning that was either cognitively based (knowledge), psychomotor (skills) or affective (attitudes and values). This led to the set-up of a matrix to collect qualitative data that was gathered using a narrative inquiry method around participants’ stories. This included focus groups with students who were part of the Eco-building Working Party, interviews with key adults from the school and the wider community, survey questionnaires to parents of the focus group students, plus classroom observations and analysis of visual diaries made by the teacher.
Findings revealed student learning occurred in all three learning domains. This included EfS learning (particularly related to architecture and the built environment), understanding a design and build process, and cross-disciplinary learning that included skills such as leadership, teamwork and public speaking. Adult participants also gained from their involvement in the project. A correlation was made between the set-up and execution of the eco-classroom project and the Danish concept of Action Competence. This was indicated through the authentic, relevant and democratic action-taking focus of the eco-classroom project, which is linked to learning transformations. Also in agreement with an action competence approach was the strong focus in the project on both individual and collective learning. This was due to the process-focused nature of the project, itself related to the learning mandate and commitment to a democratic process with students. The project ran for a number of years with annually changing groups of students, who all had different experiences. The teacher used ‘peer education’ and reflective tools to manage the changeover of students positively. This gave depth and breadth to learning and ensured the project was truly collaborative. The embedding of learning in the project within the New Zealand Curriculum provided evidence of the flexible and multidisciplinary nature of EfS. Finally, a number of key management aspects were identified by the findings as contributing significantly to learning in the project and these are discussed.
We perform a spectroscopic analysis of 492,450 galaxy spectra from the first two years of observations of the Sloan Digital Sky Survey-III/Baryonic Oscillation Spectroscopic Survey (BOSS) collaboration. This data set has been released in the ninth SDSS data release, the first public data release of BOSS spectra. We show that the typical signal-to-noise ratio of BOSS spectra is sufficient to measure stellar velocity dispersion and emission line fluxes for individual objects. The typical velocity dispersion of a BOSS galaxy is 240 km/s, with an accuracy of better than 30 per cent for 93 per cent of BOSS galaxies. The distribution in velocity dispersion is redshift independent between redshifts 0.15 and 0.7, which reflects the survey design targeting massive galaxies with an approximately uniform mass distribution in this redshift interval. The majority of BOSS galaxies lack detectable emission lines. We analyse the emission line properties and present diagnostic diagrams using the emission lines [OII], Hβ, [OIII], Halpha, and [NII] (detected in about 4 per cent of the galaxies). We show that the emission line properties are strongly redshift dependent and that there is a clear correlation between observed frame colours and emission line properties. Within in the low-z sample around 0.15 < z < 0.3, half of the emission-line galaxies have LINER-like emission line ratios, followed by Seyfert-AGN dominated spectra, and only a small fraction of a few per cent are purely star forming galaxies. AGN and LINER-like objects, instead, are less prevalent in the high-z sample around 0.4 < z < 0.7, where more than half of the emission line objects are star forming. This is a pure selection effect caused by the non-detection of weak Hβ emission lines in the BOSS spectra. Finally, we show that star forming, AGN and emission line free galaxies are well separated in the g - r vs r - i target selection diagram.
We have measured the angular two-point correlation function of EROs. The halo model is fitted to the observed clustering, and dark matter halo mass, bias and satellite fraction are estimated in three redshift bins. We also compare our results with the semi-analytical galaxy formation model. This work illustrates the power of clustering analysis in providing observational constraints on simulations.
Microglia cells are the immune cells of the central nervous system and consequently play important roles in brain infections and inflammation. Recent in vivo imaging studies have revealed that in the resting healthy brain, microglia are highly dynamic, moving constantly to actively survey the brain parenchyma. These active microglia can rapidly respond to pathological insults, becoming activated to induce a range of effects that may contribute to both pathogenesis, or to confer neuronal protection. However, interactions between microglia and neurons are being recognized as important in shaping neural circuit activity under more normal, physiological conditions. During development and neurogenesis, microglia interactions with neurons help to shape the final patterns of neural circuits important for behavior and with implications for diseases. In the mature brain, microglia can respond to changes in sensory activity and can influence neuronal activity acutely and over the long term. Microglia seem to be particularly involved in monitoring the integrity of synaptic function. In this review, we discuss some of these new insights into the involvement of microglia in neural circuits.
A model of cell-growth, describing the evolution of the age–size distribution of cells in different phases of cell-growth, is studied. The model is based on that used in several papers by Basse et al. and is composed of a system of partial differential equations, each describing the changes in the age–size distribution of cells in a specific phase of cell-growth. Here, the ‘age’ of a cell is considered to be the time spent in its current phase of cell-growth, while ‘size’ is considered to be the DNA content of the cell. The existence of steady age–size distributions (SASDs), where the age–size distributions retain the same shape but are scaled up or down as time increases, is investigated and it is shown that SASDs exist. A speculative discussion of the stability of these SASDs is also included, but their stability is not conclusively proved.
Laboratory experiments have been performed on resonantly forced interfacial waves in a circular cylindrical basin containing a two-layer stratified fluid. The results of this shallow-water study exhibit a number of similarities to previous shallow-water studies performed in single-layer fluids, such as the generation of a large-amplitude response over a frequency bandwidth offset from the primary resonance, generation of a swirling mode at the observed resonant condition, and the significant contribution of higher harmonics. The two-layer experiments also produce results that are unique to stratified domains. In particular, the observed negative nonlinearity of the resonant condition at shallow water depth, mixing of the density interface resulting in detuning the forced response from the resonant condition, the enhanced role of viscous dissipation, and an alternative pathway for the nonlinear generation of higher-frequency waves when the layer depths are disparate. The results of this study are considered with regard to their implications for enclosed basins at the geophysical scale that are subject to near resonant forcing.
In this paper, we study a class of linear functional differential equations of which the pantograph equation is a prominent member. Specifically, we study the existence of solutions holomorphic at a fixed point of the functional argument. The local theory for equations with attracting fixed points is known [17, 13], but little is known about the case where the fixed point is repelling. We formulate an eigenvalue problem for the repelling fixed point case and show that the corresponding spectrum is discrete. Hence, that holomorphic solutions occur only as special cases. The second order pantograph equation is used to illustrate this result. A key step in this process is to reformulate the problem in terms of a compact operator. Aside from exploiting well known results for the spectra of such operators, we use results such as the Fredholm Alternative to derive existence results for the non-homogeneous problem.
The Cerro de las Conchas shell mound, located on Mexico's south Pacific coast, was formed between 7,500 and 6,000/5,500 years ago, during the Middle Archaic period. Few Mesoamerican coastal sites are as early or have been studied so intensively. Limited diversity in the artifact assemblage and faunal origins, the presence of bedded strata, and the absence of features associated with permanent residency indicate that the site was used intermittently as a processing station for aquatic foods. Seasonality studies on clam shells suggest that this occurred year round. The site likely was situated initially adjacent to a brackish water lagoon near a tropical rainforest because faunal studies indicate a strong focus on lagoonal taxa, whereas a forested environment is indicated by phytoliths. Toward the end of the Middle Archaic, however, an increase in faunal and artifact richness, an emphasis on fauna with a tolerance for marine conditions, and phytolith evidence for more disturbance vegetation compared to earlier times, may be due to marine transgression. Later, pottery-using agricultural peoples used the site for farming and possibly residency. This example of early human adaptation to a coastal environment of Mesoamerica permits a corrective to previous research that is weighted heavily in favor of upland settings.