884 resultados para Seedling emergence


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Self-organization of organic molecules with carbon nanomaterials leads to formation of functionalized molecular nano-complexes with advanced features. We present a study of physical and chemical properties of carbon nanotube-surfactant-indocarbocyanine dye (astraphloxin) in water focusing on aggregation of the dye and resonant energy transfer from the dye to the nanotubes. Self-assembly of astraphloxin is evidenced in absorbance and photoluminescence depending dramatically on the concentrations of both the dye and surfactant in the mixtures. We observed an appearance of new photoluminescence peaks in visible range from the dye aggregates. The aggregates characterized with red shifted photoluminescence peaks at 595, 635 and 675 nm are formed mainly due to the presence of surfactant at the premicellar concentration. The energy transfer from the dye to the nanotubes amplifying near-infrared photoluminescence from the nanotubes is not affected by the aggregation of astraphloxin molecules providing important knowledge for further development of advanced molecular nano-complexes. The aggregation with the turned-on peaks and the energy transfer with amplified photoluminescence create powerful tools of visualization and/or detection of the nanotubes in visible and near-infrared spectral range, respectively, boosting its possible applications in sensors, energy generation/storage, and healthcare.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this paper, we examine the extent to which the concept of emergence can be applied to questions about the nature and moral justification of territorial borders. Although the term is used with many different senses in philosophy, the concept of “weak emergence” - advocated by, for example, Sawyer (2002, 2005) and Bedau (1997 ) - is especially applicable, since it forces a distinction between prediction and explanation that connects with several issues in the discussion of territory. In particular, we argue, weak emergentism about borders allows us to distinguish between (a) using a theory of territory to say where a border should be drawn, and (b) looking at an existing border and saying whether or not it is justified (Miller, 2012; Nine, 2012; Stilz, 2011). Many authors conflate these two factors, or identify them by claiming that having one without the other is in some sense incoherent. But on our account - given the concept of emergence - one might unproblematically be able to have (b) without (a); at the very least, the distinction between these two issues is much more significant than has often been recognised, and more importantly gives us some reason to prefer “statist” as opposed to “cultural” theories of territorial borders. We conclude with some further reflections on related matters concerning, firstly, the apparent causal powers of borders, and secondly, the different ways in which borders are physically implemented (e.g., land vs. water).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The current era of American Christianity marks the transition from a Western, white-dominated U.S. Evangelicalism to an ethnically diverse demographic for evangelicalism. Despite this increasing diversity, U.S. Evangelicalism has demonstrated a stubborn inability to address the entrenched assumption of white supremacy. The 1970s witnessed the rise in prominence of Evangelicalism in the United States. At the same time, the era witnessed a burgeoning movement of African-American evangelicals, who often experienced marginalization from the larger movement. What factors prevented the integration between two seemingly theologically compatible movements? How do these factors impact the challenge of integration and reconciliation in the changing demographic reality of early twenty-first Evangelicalism?

The question is examined through the unpacking of the diseased theological imagination rooted in U.S. Evangelicalism. The theological categories of Creation, Anthropology, Christology, Soteriology, and Ecclesiology are discussed to determine specific deficiencies that lead to assumptions of white supremacy. The larger history of U.S. Evangelicalism and the larger story of the African-American church are explored to provide a context for the unique expression of African-American evangelicalism in the last third of the twentieth century. Through the use of primary sources — personal interviews, archival documents, writings by principals, and private collection documents — the specific history of African-American evangelicals in the 1960s and 1970s is described. The stories of the National Black Evangelical Association, Tom Skinner, John Perkins, and Circle Church provide historical snapshots that illuminate the relationship between the larger U.S. Evangelical movement and African-American evangelicals.

Various attempts at integration and shared leadership were made in the 1970s as African-American evangelicals engaged with white Evangelical institutions. However, the failure of these attempts point to the challenges to diversity for U.S. Evangelicalism and the failure of the Evangelical theological imagination. The diseased theological imagination of U.S. Evangelical Christianity prevented engagement with the needed challenge of African American evangelicalism, resulting in dysfunctional racial dynamics evident in twenty-first century Evangelical Christianity. The historical problem of situating African American evangelicals reveals the theological problem of white supremacy in U.S. Evangelicalism.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. This image is made available for non-commercial or educational use only.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

BACKGROUND: Multiyear epidemics of Salmonella enterica serovar Typhi have been reported from countries across eastern and southern Africa in recent years. In Blantyre, Malawi, a dramatic increase in typhoid fever cases has recently occurred, and may be linked to the emergence of the H58 haplotype. Strains belonging to the H58 haplotype often exhibit multidrug resistance and may have a fitness advantage relative to other Salmonella Typhi strains.

METHODS: To explore hypotheses for the increased number of typhoid fever cases in Blantyre, we fit a mathematical model to culture-confirmed cases of Salmonella enterica infections at Queen Elizabeth Central Hospital, Blantyre. We explored 4 hypotheses: (1) an increase in the basic reproductive number (R0) in response to increasing population density; (2) a decrease in the incidence of cross-immunizing infection with Salmonella Enteritidis; (3) an increase in the duration of infectiousness due to failure to respond to first-line antibiotics; and (4) an increase in the transmission rate following the emergence of the H58 haplotype.

RESULTS: Increasing population density or decreasing cross-immunity could not fully explain the observed pattern of typhoid emergence in Blantyre, whereas models allowing for an increase in the duration of infectiousness and/or the transmission rate of typhoid following the emergence of the H58 haplotype provided a good fit to the data.

CONCLUSIONS: Our results suggest that an increase in the transmissibility of typhoid due to the emergence of drug resistance associated with the H58 haplotype may help to explain recent outbreaks of typhoid in Malawi and similar settings in Africa.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

INTRODUCTION: Between 1998 and 2010, S. Typhi was an uncommon cause of bloodstream infection (BSI) in Blantyre, Malawi and it was usually susceptible to first-line antimicrobial therapy. In 2011 an increase in a multidrug resistant (MDR) strain was detected through routine bacteriological surveillance conducted at Queen Elizabeth Central Hospital (QECH).

METHODS: Longitudinal trends in culture-confirmed Typhoid admissions at QECH were described between 1998-2014. A retrospective review of patient cases notes was conducted, focusing on clinical presentation, prevalence of HIV and case-fatality. Isolates of S. Typhi were sequenced and the phylogeny of Typhoid in Blantyre was reconstructed and placed in a global context.

RESULTS: Between 1998-2010, there were a mean of 14 microbiological diagnoses of Typhoid/year at QECH, of which 6.8% were MDR. This increased to 67 in 2011 and 782 in 2014 at which time 97% were MDR. The disease predominantly affected children and young adults (median age 11 [IQR 6-21] in 2014). The prevalence of HIV in adult patients was 16.7% [8/48], similar to that of the general population (17.8%). Overall, the case fatality rate was 2.5% (3/94). Complications included anaemia, myocarditis, pneumonia and intestinal perforation. 112 isolates were sequenced and the phylogeny demonstrated the introduction and clonal expansion of the H58 lineage of S. Typhi.

CONCLUSIONS: Since 2011, there has been a rapid increase in the incidence of multidrug resistant, H58-lineage Typhoid in Blantyre. This is one of a number of reports of the re-emergence of Typhoid in Southern and Eastern Africa. There is an urgent need to understand the reservoirs and transmission of disease and how to arrest this regional increase.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Abstract:
This paper combines demographic ageing and retirement lifestyles with rural in-migration processes and suggests the emergence of a specific rural form of gated community; namely, park homes. All year round or permanent (as opposed to seasonal) residential mobile homes (resembling detached bungalows in design and appearance) are commonly referred to as 'park homes'. With a growing proportion of the UK population aged 65 and over, combined with increasing longevity, meeting the residential preferences and lifestyle aspirations of an ageing population is potentially 'big business' for the private sector. Park home living, with their resident age restrictions (normally 50 years and over), is increasingly marketed as a retirement option in rural and coastal locations of the UK. However, many areas are often remote with declining populations and limited community services. Operators have sought to tap into retiree aspirations for a 'place in the country' and 'sell' the concept of park home living as a specific form of housing, community and lifestyle. Park homes are frequently marketed as a means to release equity from the sale of a large family home to fund a retirement lifestyle and as friendly communities of like-minded people, always willing to lend support or provide assistance if required. The physical and social composition of such sites represent a form of rural gated community. This paper seeks to identify the rural planning issues which emerge from such developments and asks: who are moving to park home sites and why? do park homes provide those who otherwise could not afford a 'place in the country' the option of rural living? does park home living live-up to residents' expectations of the rural idyll or retirement lifestyle? do they give rise to issues of gentrification and geriatrification of the countryside? what are the prospects for residents to 'age in place'? might ageing residents become financially trapped in such developments giving rise to park ghettoization? what are the associated challenges for rural policy-makers and public service providers?

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Three experiments examined the development of episodic future thinking: the ability to think ahead about novel future situations (Atance & O’Neill, 2001). Each experiment used three novel tasks, similar to the Blow Football task used by Russell, Alexis, and Clayton (2010). In each, there was a different table top with two sides. Children played a game on one side of a table, and then were asked to choose a tool to play with a similar game on the other side of the table the next day. For example, children used a toy fishing rod to catch magnetic fish on one side of the table; playing the same game from the other side of the table required a different type of fishing rod. At test, children chose between 2 or 3 tools: a) the tool they used today, b) the tool suitable for the other side (correct) and c) a distractor tool which was not suitable for either side. In Experiment 1, 24 four-year-olds selected 1 out of 2 tools for tomorrow. Children selected the correct item above chance level in all tasks (p < 0.001). In Experiment 2, in which children were not allowed to look at the apparatus when choosing, 21 three-year olds selected 1 out of 2 tools for tomorrow. This group also selected the right tool above chance level in all tasks (p < 0.001).The results of Experiments 1 and 2 imply that 3- and 4-year olds might indeed show episodic future foresight. However, they could have also selected the right tool by default. To control for this, a third tool distractor was introduced in Experiment 3. This time, 3-4 year olds did not perform above chance levels, suggesting that there is an alternative explanation as to why they performed so well in the previous two experiments.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Educational systems worldwide are facing an enormous shift as a result of sociocultural, political, economic, and technological changes. The technologies and practices that have developed over the last decade have been heralded as opportunities to transform both online and traditional education systems. While proponents of these new ideas often postulate that they have the potential to address the educational problems facing both students and institutions and that they could provide an opportunity to rethink the ways that education is organized and enacted, there is little evidence of emerging technologies and practices in use in online education. Because researchers and practitioners interested in these possibilities often reside in various disciplines and academic departments the sharing and dissemination of their work across often rigid boundaries is a formidable task. Contributors to Emergence and Innovation in Digital Learning include individuals who are shaping the future of online learning with their innovative applications and investigations on the impact of issues such as openness, analytics, MOOCs, and social media. Building on work first published in Emerging Technologies in Distance Education, the contributors to this collection harness the dispersed knowledge in online education to provide a one-stop locale for work on emergent approaches in the field. Their conclusions will influence the adoption and success of these approaches to education and will enable researchers and practitioners to conceptualize, critique, and enhance their understanding of the foundations and applications of new technologies.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Emerging infectious diseases are a growing concern in wildlife conservation. Documenting outbreak patterns and determining the ecological drivers of transmission risk are fundamental to predicting disease spread and assessing potential impacts on population viability. However, evaluating disease in wildlife populations requires expansive surveillance networks that often do not exist in remote and developing areas. Here, we describe the results of a community-based research initiative conducted in collaboration with indigenous harvesters, the Inuit, in response to a new series of Avian Cholera outbreaks affecting Common Eiders (Somateria mollissima) and other comingling species in the Canadian Arctic. Avian Cholera is a virulent disease of birds caused by the bacterium Pasteurella multocida. Common Eiders are a valuable subsistence resource for Inuit, who hunt the birds for meat and visit breeding colonies during the summer to collect eggs and feather down for use in clothing and blankets. We compiled the observations of harvesters about the growing epidemic and with their assistance undertook field investigation of 131 colonies distributed over >1200 km of coastline in the affected region. Thirteen locations were identified where Avian Cholera outbreaks have occurred since 2004. Mortality rates ranged from 1% to 43% of the local breeding population at these locations. Using a species-habitat model (Maxent), we determined that the distribution of outbreak events has not been random within the study area and that colony size, vegetation cover, and a measure of host crowding in shared wetlands were significantly correlated to outbreak risk. In addition, outbreak locations have been spatially structured with respect to hypothesized introduction foci and clustered along the migration corridor linking Arctic breeding areas with wintering areas in Atlantic Canada. At present, Avian Cholera remains a localized threat to Common Eider populations in the Arctic; however expanded, community-based surveillance will be required to track disease spread.