938 resultados para Ilustraciones de Historia Natural


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The approach to remove greenhouse gases by pumping liquid CO2 several kilometres below the ground implies that many carbonate containing minerals will be formed. Among these minerals, the formation of hydromagnesite, dypingite and nesquehonite are possible, thus necessitating a study of such minerals. These minerals with a hydrotalcite-related formulae have been characterised by a combination of infrared and near infrared spectroscopy. Layered double hydroxides (also known as anionic clays or hydrotalcites) are a group of layered clay minerals described by the general formula: [M1–x2+Mx3+(OH)2]x+[An–]x/n∙mH2O. The infrared spectra of the minerals are characterised by OH and water stretching vibrations. Both the first and second fundamental overtones of these bands are observed in the NIR spectra in the 7030–7235 cm–1 and 10,490–10,570 cm–1 spectral ranges. Intense (CO3)2– symmetrical and anti-symmetrical stretching vibrations confirm the distortion of the carbonate anion. The position of the water bending vibration indicates water is strongly hydrogen-bonded to the carbonate anion in the mineral structure. NIR spectroscopy offers a method for quickly analysing such materials.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Husserl reminded us of the imperative to return to the Lebensweldt, or life-world. He was preoccupied with the crisis of Western science which alienated the experiencing self from the world of immediate experience. Immediate experience provides a foundation for what it means to be human. Heidegger, building upon these ideas, foresaw a threat to human nature in the face of ‘technicity’. He argued for a return to a relationship between ‘authentic self’ and nature predicated upon the notion of ‘letting be’ in which humans are open to the mystery of being. Self and nature are not conceived as alienated entities but as aspects of a single entity. In modern times, separation between self and the world is further evidenced by scientific rational modes of being exemplified through consumerism and the incessant use of screen-based technology which dominate human experience. In contrast, extreme sports provide an opportunity for people to return to the life-world by living in relation to the natural world. Engagement in extreme sports enables a return to authenticity as we rediscover self as part of nature.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The past decade has seen an increase in the occurrence of natural hazards and the experience in Australia has led to a reconsideration of the planning for natural hazards by government and to the adoption of a whole-of-nation resilience-based approach to disaster management. A key component of creating community resilience is the integration of disaster management with government and community strategic planning in relation to the social, built, economic and natural environments. Joint responsibility of government and the community for ‘land use planning systems and building control arrangements [which] reduce, as far as is practicable, community exposure to unreasonable risks from known hazards’, is a critical element of a resilient community. As the responsibility for the implementation of land use planning policies in Australia is generally with local governments, this paper will examine whether, in light of improved predictive technology, the failure of a local government to adequately foresee and make provision for a known hazard will give rise to liability for damage or loss of property caused by that hazard.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Biophilic urbanism, or urban design that reflects humanity’s innate need for nature, stands to make significant contributions to a range of national, state and local government policies related to climate change mitigation and adaptation, by investigating ways in which nature can be integrated into, around and on top of buildings. Potential benefits of such design include reducing the heat island effect, reducing energy consumption for thermal control, enhancing urban biodiversity, improving well being and productivity, improving water cycle management, and assisting in the response to growing needs for densification and revitalisation of cities. This report will give an overview of the concept of biophilia and consider enablers and disablers to its application to urban planning and design. The paper will present findings from stakeholder engagement and a series of detailed case studies, related to a consideration of the economics of the use of biophilic elements (direct and indirect).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Both red snow crab (Chionoecetes japonicus Rathbun, 1932) and snow crab (Chionoecetes opilio Fabricius, 1788) are commercially important species in Korea. The geographical ranges of the two species overlap in the East Sea, where both species are fished commercially. Morphological identification of the two species and putative hybrids can be difficult because of their overlapping morphological characteristics. The presence of putative hybrids can affect the total allowable catch (TAC) of C. japonicus and C. opilio, and causes problems managing C. japonicus and C. opilio wild resources. To date, however, no natural hybridization has been reported between C. japonicus and C. opilio, despite their overlapping distributions along the coast of the East Sea. In this study, the internal transcribed spacer (ITS) region of major ribosomal RNA genes from the nuclear genome and the cytochrome oxidase I (CO I) gene from the mitochondrial genome were sequenced to determine whether natural hybridization occurs between the two species. Our results revealed that all putative hybrids identified using morphological traits had two distinct types of ITS sequences corresponding to those of both parental species. Mitochondrial CO I gene sequencing showed that all putative hybrids had sequences identical to C. japonicus. A genotyping assay based on single nucleotide polymorphisms in the ITS1 region and the CO I gene produced the most efficient and accurate identification of all hybrid individuals. Molecular data clearly demonstrate that natural hybridization does occur between C. japonicus and C. opilio, but only with C. japonicus as the maternal parent.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Complex intersecting social, economic and environmental dilemmas in Australia's Cape York Peninsula present a number of challenges for planners seeking to develop and implement land use and natural resource management (NRM) plans. There have been five different attempts at land use and NRM planning in Cape York Peninsula over the last 20 years. These processes have (to greater or lesser extents) failed to deliver community-owned and government-supported plans to guide development and/or the management of the region's natural resources. The region is remote, sparsely populated, and home to a significant Indigenous population. Much of the contestation within the region surrounds the access, use and ownership of the region's internationally valuable natural resources. This paper reviews, from the literature, the relevancy and applicability of criteria for best practice planning and governance. A range of identified best practice governance and planning principles are applied to assess the governance arrangements for planning in the Peninsula. The paper finds that decision-making arrangements for land use and NRM planning in the Peninsula are still in their infancy and are inadequate to support effective outcomes. The paper concludes that broader attention to best practice principles in governance for planning is needed to improve planning outcomes.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The visual characteristics of urban environments have been changing dramatically with the growth of cities around the world. Protection and enhancement of landscape character in urban environments have been one of the challenges for policy makers in addressing sustainable urban growth. Visual openness and enclosure in urban environments are important attributes in perception of visual space which affect the human interaction with physical space and which can be often modified by new developments. Measuring visual openness in urban areas results in more accurate, reliable, and systematic approach to manage and control visual qualities in growing cities. Recent advances in techniques in geographic information systems (GIS) and survey systems make it feasible to measure and quantify this attribute with a high degree of realism and precision. Previous studies in this field do not take full advantage of these improvements. This paper proposes a method to measure the visual openness and enclosure in a changing urban landscape in Australia, on the Gold Coast, by using the improved functionality in GIS. Using this method, visual openness is calculated and described for all publicly accessible areas in the selected study area. A final map is produced which shows the areas with highest visual openness and visibility to natural landscape resources. The output of this research can be used by planners and decision-makers in managing and controlling views in complex urban landscapes. Also, depending on the availability of GIS data, this method can be applied to any region including non-urban landscapes to help planners and policy-makers manage views and visual qualities.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

IL-2, IL-4 and IFN-γ mRNA expression, and production of IFN-γ was examined in mesenteric lymph node cells (MLNC) and CD4+ enriched T cell populations of nematode resistant (R) and susceptible (S) line lambs by use of RT-PCR and ELISA. Five R and S line lambs that were immunised by repeated oxfendazole-abbreviated infections and 5 non-immunised R and S line lambs were used. All lambs grazed nematode infected pasture for 107 days. Immunisation enhanced the resistant status in both R and S lambs. MLNC obtained from slaughtered animals were stimulated with Con A or T. colubriformis specific antigen. Non-stimulated MLNC of immunised lambs expressed higher levels of IL-4 mRNA and lower levels of IL-2 mRNA than non-immunised lambs. MLNC of immunised R and S line lambs stimulated with antigen for 24 h expressed detectable amounts of IL-4 mRNA that was not seen in non-immunised controls. CD4+ T cell enriched cell populations of immunised R and S lambs and non-immunised R lambs expressed moderate to high levels of IL-4 mRNA. Con A stimulated MLNC of immunised R and S lambs expressed high levels IFN-γ mRNA and produced high amounts of IFN-γ. Lower levels were present in non-immunised controls. The results indicate that R line lambs and immunised S line lambs respond to natural nematode challenge with a predominating IL-4 cytokine response when compared to non-immunised S lambs.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Natural gas (the main component is methane) has been widely used as a fuel and raw material in industry. Removal of nitrogen (N2) from methane (CH4) can reduce the cost of natural gas transport and improve its efficiency. However, their extremely similar size increases the difficulty of separating N2 from CH4. In this study, we have performed a comprehensive investigation of N2 and CH4 adsorption on different charge states of boron nitride (BN) nanocage fullerene, B36N36, by using a density functional theory approach. The calculational results indicate that B36N36 in the negatively charged state has high selectivity in separating N2 from CH4. Moreover, once the extra electron is removed from the BN nanocage, the N2 will be released from the material. This study demonstrates that the B36N36 fullerene can be used as a highly selective and reusable material for the separation of N2 from CH4. The study also provides a clue to experimental design and application of BN nanomaterials for natural gas purification.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this article, natural convection boundary layer flow is investigated over a semi-infinite horizontal wavy surface. Such an irregular (wavy) surface is used to exchange heat with an external radiating fluid which obeys Rosseland diffusion approximation. The boundary layer equations are cast into dimensionless form by introducing appropriate scaling. Primitive variable formulations (PVF) and stream function formulations (SFF) are independently used to transform the boundary layer equations into convenient form. The equations obtained from the former formulations are integrated numerically via implicit finite difference iterative scheme whereas equations obtained from lateral formulations are simulated through Keller-box scheme. To validate the results, solutions produced by above two methods are compared graphically. The main parameters: thermal radiation parameter and amplitude of the wavy surface are discussed categorically in terms of shear stress and rate of heat transfer. It is found that wavy surface increases heat transfer rate compared to the smooth wall. Thus optimum heat transfer is accomplished when irregular surface is considered. It is also established that high amplitude of the wavy surface in the boundary layer leads to separation of fluid from the plate.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study is concerned with transient natural convection in an isosceles triangular enclosure subject to non-uniformly cooling at the inclined surfaces and uniformly heating at the base. The numerical simulations of the unsteady flows over a range of Rayleigh numbers and aspect ratios are carried out using Finite Volume Method. Since the upper inclined surfaces are linearly cooled and the bottom surface is heated, the flow is potentially unstable. It is revealed from the numerical simulations that the transient flow development in the enclosure can be classified into three distinct stages; an early stage, a transitional stage, and a steady stage. The flow inside the enclosure depends significantly on the governing parameters, Rayleigh number and aspect ratio. The effect of Rayleigh number and aspect ratio on the flow development and heat transfer rate are discussed. The key finding for this study is to analyze the pitchfork bifurcation of the flow about the geometric center line. The heat transfer through the roof and the ceiling as a form of Nusselt number is reported in this study.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Acoustic recordings play an increasingly important role in monitoring terrestrial environments. However, due to rapid advances in technology, ecologists are accumulating more audio than they can listen to. Our approach to this big-data challenge is to visualize the content of long-duration audio recordings by calculating acoustic indices. These are statistics which describe the temporal-spectral distribution of acoustic energy and reflect content of ecological interest. We combine spectral indices to produce false-color spectrogram images. These not only reveal acoustic content but also facilitate navigation. An additional analytic challenge is to find appropriate descriptors to summarize the content of 24-hour recordings, so that it becomes possible to monitor long-term changes in the acoustic environment at a single location and to compare the acoustic environments of different locations. We describe a 24-hour ‘acoustic-fingerprint’ which shows some preliminary promise.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Elucidating the nature of genetic variation underlying both sexually selected traits and the fitness components of sexual selection is essential to understanding the broader consequences of sexual selection as an evolutionary process. To date, there have been relatively few attempts to connect the genetic variance in sexually selected traits with segregating DNA sequence polymorphisms. We set out to address this in a well-characterized sexual selection system - the cuticular hydrocarbons (CHCs) of Drosophila serrata - using an indirect association study design that allowed simultaneous estimation of the genetic variance in CHCs, sexual fitness and single nucleotide polymorphism (SNP) effects in an outbred population. We cloned and sequenced an ortholog of the D. melanogaster desaturase 2 gene, previously shown to affect CHC biosynthesis in D. melanogaster, and associated 36 SNPs with minor allele frequencies > 0.02 with variance in CHCs and sexual fitness. Three SNPs had significant multivariate associations with CHC phenotype (q-value < 0.05). At these loci, minor alleles had multivariate effects on CHCs that were weakly associated with the multivariate direction of sexual selection operating on these traits. Two of these SNPs had pleiotropic associations with male mating success, suggesting these variants may underlie responses to sexual selection due to this locus. There were 15 significant male mating success associations (q-value < 0.1), and interestingly, we detected a nonrandom pattern in the relationship between allele frequency and direction of effect on male mating success. The minor-frequency allele usually reduced male mating success, suggesting a positive association between male mating success and total fitness at this locus.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This project proposes a framework that identifies high‐value disaster-based information from social media to facilitate key decision-making processes during natural disasters. At present it is very difficult to differentiate between information that has a high degree of disaster relevance and information that has a low degree of disaster relevance. By digitally harvesting and categorising social media conversation streams automatically, this framework identifies highly disaster-relevant information that can be used by emergency services for intelligence gathering and decision-making.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Natural nanopatterned surfaces (nNPS) present on insect wings have demonstrated bactericidal activity [1, 2]. Fabricated nanopatterned surfaces (fNPS) derived by characterization of these wings have also shown superior bactericidal activity [2]. However bactericidal NPS topologies vary in both geometry and chemical characteristics of the individual features in different insects and fabricated surfaces, rendering it difficult to ascertain the optimum geometrical parameters underling bactericidal activity. This situation calls for the adaptation of new and emerging techniques, which are capable of fabricating and characterising comparable structures to nNPS from biocompatible materials. In this research, CAD drawn nNPS representing an area of 10 μm x10 μm was fabricated on a fused silica glass by Nanoscribe photonic professional GT 3D laser lithography system using two photon polymerization lithography. The glass was cleaned with acetone and isopropyl alcohol thrice and a drop of IP-DIP photoresist from Nanoscribe GmbH was cast onto the glass slide prior to patterning. Photosensitive IP-DIP resist was polymerized with high precision to make the surface nanopatterns using a 780 nm wavelength laser. Both moving-beam fixedsample (MBFS) and fixed-beam moving-sample (FBMS) fabrication approaches were tested during the fabrication process to determine the best approach for the precise fabrication of the required nanotopological pattern. Laser power was also optimized to fabricate the required fNPS, where this was changed from 3mW to 10mW to determine the optimum laser power for the polymerization of the photoresist for fabricating FNPS...