1000 resultados para transitional fauna


Relevância:

60.00% 60.00%

Publicador:

Resumo:

A small brachiopod fauna is described from the lower part of the Xiujimqinqi Formation of the Xiujimqinqi area in central-east Inner Mongolia, northeast China. The age of this fauna is regarded as Wordian (Middle Guadalupian, Middle Permian) by comparison with a similar brachiopod fauna from the Zhesi area of central Inner Mongolia, and by constraints from fusulinaceans associated with the Zhesi fauna. The Xiujimqinqi fauna is typical of mixed Boreal/Palaeoequatorial Middle Permian brachiopod faunas of East Asia. The mixed nature of these faunas is interpreted to have resulted from the combined effects of a middle palaeolatitudinal position, intensified plate convergence between Sino-Korea and Mongolia, and sea surface current connections with both the Arctic Sea in the north and eastern Palaeo-Tethys to the south. Possible Kaninospirifer is reported for the first time from China.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Estuaries are poles of attraction for human settlement which is a source of pressures to surface water bodies. The implementation of the European Water Framework Directive (WDF, 2000/60/EC) has increased the investigation in order to develop methodologies to assess the Ecological Quality Status (EQS) of aquatic ecosystems. Transitional systems are naturally stressed and characterized by highly dynamic physical, chemical and hydro-morphologic conditions and by species with a higher level of tolerance to change, being more difficult to develop suitable quality indicators for these systems. The general purpose of this study is to test the ability of synthesis descriptors, including primary (S, taxa richness) and derived biological variable (H’, Shannon-Wiener diversity), biotic indices (AMBI and M-AMBI), body size properties (abundance distribution by body size classes, length, weight and length-weight relationships) and non-taxonomic indices (ISS), as well as functional indicators related to the decomposition rates of various experimental substrates, a macrophyte (Phragmites australis) and an alga (Fucus vesiculosus), to evaluate the environmental quality in transitional systems. This study was carried out in one of the most pristine channels of the Ria the Aveiro, Mira Channel, along a full salinity gradient and in a metals and metalloid sediment contamination area, the Estarreja Channel, and two reference channels (Canelas and Salreu). In this study were used different sampling techniques, the leaf-bag technique and a hand-held corer. In Mira Channel, the alga and the macrophyte presented an opposite trend in the decomposition rate along the salinity gradient, with the decomposition rates of the alga always higher than those of the macrophyte. The decomposition rates of the macrophyte and the alga were higher in the mid estuary and in higher salinity areas, respectively, corresponding to the preferencial distribution areas of each species. The macrobenthic fauna associated with the decaying and an artificial substrate (control) showed equally well the benthic succession from the marine to the freshwater areas and, despite the strong differences in the decay rates, no significant differences were found between the benthic communities associated with the alga and the macrophyte. The body size properties of the macrobenthic fauna associated with the P. australis leaf-bag (1mm and 5mm) and corer samples were studied along the full salinity gradient. The dominant species of the sub-set of measured specimens were not the same of the original macrobenthic fauna sampled but, despite that, the sub-set of measured specimens was also able to show the benthic succession from the marine to the freshwater areas. The body size abundance distribution of the benthic macroinvertebrates according to the ISS size classes did not show a particular trend in any sampler along the salinity gradient. Significant differences were found in the length, weight and length-weight relationships of Annelids, , Molluscs and even some species along the salinity gradient. No significant differences were found in the AMBI, M-AMBI and ISS values along the salinity gradient for all the samplers. The EQS of the corer samples obtained using the M-AMBI was lower than that of the leaf-bags. The EQS obtained with the ISS was higher than that obtained with the M-AMBI in the leaf-bags but not in the corer samples. The ecological effects of contaminated sediments associated with the industrial chemical effluents discharged in the Estarreja Channel were studied a decade after ceasing the emissions, using the Sediment Quality Triad approach and two reference channels. The results showed that despite the emissions ceased in 2004, the sediment remains polluted with high levels of metals and metalloid, available to bioaccumulation and with severe consequences at the community level. The sediment contamination problem was also studied using the leaf-bag technique with a macrophyte, an alga and a control substrate. The results showed that the decay rates, the associated macrofauna and the application of the AMBI, M-AMBI and ISS indices to the mesh-bag samples were not able to identify the sediment contamination. Contrarily to the AMBI, the M-AMBI and the ISS showed significant differences between the contaminated and the reference channels for the corer samples. Although such statistical significance, the interest of using these complex biotic indices could be questioned, when much simple ones, like the S and H’ allow to reach the same conclusions.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

A total of 17 brachiopod species belonging to 15 genera are recorded from a limestone block of about 3×4 km2 in the Indus–Tsangbo suture zone at Xiukang in Lhaze County of Tibet. The brachiopod fauna generally indicates a Late Guadalupian age (late Wordian–Capitanian, late Middle Permian) based on its association with the Timorites-bearing ammonoid fauna and the presence of the brachiopod Urushtenoidea crenulata. Palaeobiogeographically, the fauna exhibits transitional/mixed characters between the warm-water Cathaysian and cold to temperate Gondwanan faunas and may have developed on a carbonate build-up or seamount on the oceanic crust.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

A Kubergandian (Kungurian) fusuline fauna from the lower part of the Lugu Formation in the Cuozheqiangma area, central Qiangtang Block is described. This fusuline fauna belongs to the Southern Transitional Zone in palaeobiogeography, and is characterised by the presence of the distinctive bi-temperate genus Monodiexodina and many genera common in lower latitude Tethyan areas such as Parafusulina and Pseudodoliolina. The occurrence of Monodiexodina in the fauna confirms that the seamount-type carbonates of the Lugu Formation did not originate from the Palaeotethys Ocean, but rather from a branch of the Neotethys Ocean after the rifting of the Qiangtang Block from the Tethys Himalaya area in the Artinskian. © 2014 Geological Society of China.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The aim of the present study was to describe the species composition and reproductive modes of an anuran community from a transition area between the Amazonia and Cerrado biomes. Data were collected in habitats exhibiting different degrees of anthropogenic degradation. The community (35 species) identified during the present study presented a larger number of reproductive modes when compared with those from Cerrado communities, but smaller than those of other sites in the Amazon. While all nine modes were recorded in the gallery forests of local rivers and streams, anthropogenic habitats (rubber tree orchards and soybean fields) were occupied only by species adapted to environments where humidity is low, typical of the Cerrado. Overall, the anuran fauna of the study area was characterized by species that depend on access to water bodies for their reproduction, with only a few specialized species able to reproduce in dry environments.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Planktonic foraminiferal diversity, equitability and biostratigraphic analysis of samples from Ocean Drilling Program (ODP) Leg 122, Hole 762C show that in general, cool water conditions prevailed during the latest Campanian-Maastrichtian in the eastern Indian Ocean. This is indicated by planktonic foraminiferal assemblages characterized by low species diversity and equitability with abundant rugoglobigerinids and heterohelicids. Archaeoglobigerinids, globigerinelloids, hedbergellids, and long-ranging double-keeled globotruncanids are also present in varying abundance but single-keeled forms occur rarely and sporadically. Identification of the stage and zonal boundaries for the studied geologic interval have been achieved through biostratigraphic analyses of closely spaced samples. Three planktonic foraminiferal biozones were identified, namely; in stratigraphic order, the Heterohelix rajagopalani, Contusotruncana contusa and Abathomphalus mayaroensis Zones. In Hole 762C, a Transitional Realm with Austral influences is defined for the latest Campanian to Maastrichtian, as shown by the high relative abundance of fauna characteristic of Transitional and Austral Realms. Austral endemic species such as Archaeoglobigerina australis Huber and Hedbergella sliteri Huber were found in the samples studied but Globigerinelloides impensus Sliter andA rchaeoglobigerina mateola Huber are conspicuously absent. From the latest Campanian to middle Maastrichtian, cooler parts of the Transitional Realm prevailed. A slight warming trend is assumed towards the end of the middle Maastrichtian because the faunas contain more species indicative of warm water conditions. The late Maastrichtian also appears to have been warmer than the latest Campanian-middle Maastrichtian. This conclusion is based on the high diversity and equitability values and recognition of some thermophilic taxa. A Tethyan influence is inferred for the latest Maastrichtian on the basis of an increase of planktonic foraminiferal species diversity and occurrences of several keeled taxa.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Aijt-Sahalia (2002) introduced a method to estimate transitional probability densities of di®usion processes by means of Hermite expansions with coe±cients determined by means of Taylor series. This note describes a numerical procedure to ¯nd these coe±cients based on the calculation of moments. One advantage of this procedure is that it can be used e®ectively when the mathematical operations required to ¯nd closed-form expressions for these coe±cients are otherwise infeasible.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Joining any new community involves transition and adaptation. Just as we learn to adapt to different cultures when we choose to live abroad, so students learn the language and culture of an academic community in order to succeed within that environment. At the same time however, students bring with them individual learning styles and expectations, influenced by their prior experiences of learning and of life more generally. Some have excelled at school; others have come to fashion seeking something in which to excel for the first time. Commencing a degree in fashion design brings students into contact with peers and lecturers who share their passion, providing them with a community of practice which can be both supportive and at the same time intimidating.----- In Queensland where university level study in fashion is such a new phenomenon, few applicants have any depth of training in design when they apply to study fashion. Unlike disciplines such as Dance or Visual Art, where lecturers can expect a good level of skill upon entry to a degree program, we have to look for the potential evidenced in an applicant’s portfolio, much of which is untutored work that they have generated themselves in preparation for application. This means that many first year fashion students at QUT whilst very passionate about the idea of fashion design are often very naïve about the practice of fashion design, with limited knowledge of the history or cultural context of fashion and few of the technical skills needed to translate their ideas into three dimensional products.----- For teachers engaging with first year students in the design studios, it is critical to be cognizant of this mix of different experiences, expectations and emotions in order to design curricula and assessment that stretch and engage students without unduly increasing their sense of frustration and anxiety. This paper examines a first year project designed to provide an introduction to design process and to learning within a creative discipline. The lessons learnt provide a valuable and transferable resource for lecturers in a variety of art and design disciplines.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Purpose: The aim of this study was to identify the transitional employment aspirations and training and development needs of older and younger workers at risk of early retirement due to limited education and/or employment in blue collar occupations. Design/ Methodology/ Approach: A computer based methodology was used to evaluate the demographic effects of gender, education level and occupation group on aspirations pertaining to transitional employment and training and development in a sample of over 1000 Local Government employees. Findings: Older blue collar, secondary school educated and younger workers were less interested in transitional employment than older workers with higher levels of education or from white collar backgrounds. The early retirement risk factors of blue collar work and secondary school education had a more limited effect on perceived training and development needs for older workers. However for younger workers, these risk factors provided the impetus to undertake training to move into less physically demanding or more challenging roles as their careers progressed. Practical Implications: Via the identification of education level and occupation types groups’ transitional employment aspirations and perceptions of preparatory training and development within younger and older cohorts, long term strategies to develop and retain staff may be formulated. Originality/ Value: Past studies of transitional employment have rarely included younger workers or older workers at risk of early retirement. Preparatory training and development for transitional employment roles has not been considered in the literature.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The purpose of the current article was to explore perceptions of transitional employment and training and development amongst blue collar workers employed in technical, trade, operations or physical and labour-intensive occupations within the local government system.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The stylized facts that motivate this thesis include the diversity in growth patterns that are observed across countries during the process of economic development, and the divergence over time in income distributions both within and across countries. This thesis constructs a dynamic general equilibrium model in which technology adoption is costly and agents are heterogeneous in their initial holdings of resources. Given the households‟ resource level, this study examines how adoption costs influence the evolution of household income over time and the timing of transition to more productive technologies. The analytical results of the model constructed here characterize three growth outcomes associated with the technology adoption process depending on productivity differences between the technologies. These are appropriately labeled as „poverty trap‟, „dual economy‟ and „balanced growth‟. The model is then capable of explaining the observed diversity in growth patterns across countries, as well as divergence of incomes over time. Numerical simulations of the model furthermore illustrate features of this transition. They suggest that that differences in adoption costs account for the timing of households‟ decision to switch technology which leads to a disparity in incomes across households in the technology adoption process. Since this determines the timing of complete adoption of the technology within a country, the implications for cross-country income differences are obvious. Moreover, the timing of technology adoption appears to be impacts on patterns of growth of households, which are different across various income groups. The findings also show that, in the presence of costs associated with the adoption of more productive technologies, inequalities of income and wealth may increase over time tending to delay the convergence in income levels. Initial levels of inequalities in the resources also have an impact on the date of complete adoption of more productive technologies. The issue of increasing income inequality in the process of technology adoption opens up another direction for research. Specifically increasing inequality implies that distributive conflicts may emerge during the transitional process with political- economy consequences. The model is therefore extended to include such issues. Without any political considerations, taxes would leads to a reduction in inequality and convergence of incomes across agents. However this process is delayed if politico-economic influences are taken into account. Moreover, the political outcome is sub optimal. This is essentially due to the fact that there is a resistance associated with the complete adoption of the advanced technology.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Global warming is already threatening many animal and plant communities worldwide, however, the effect of climate change on bat populations is poorly known. Understanding the factors influencing the survival of bats is crucial to their conservation, and this cannot be achieved solely by modern ecological studies. Palaeoecological investigations provide a perspective over a much longer temporal scale, allowing the understanding of the dynamic patterns that shaped the distribution of modern taxa. In this study twelve microchiropteran fossil assemblages from Mount Etna, central-eastern Queensland, ranging in age from more than 500,000 years to the present day, were investigated. The aim was to assess the responses of insectivorous bats to Quaternary environmental changes, including climatic fluctuations and recent anthropogenic impacts. In particular, this investigation focussed on the effects of increasing late Pleistocene aridity, the subsequent retraction of rainforest habitat, and the impact of cave mining following European settlement at Mount Etna. A thorough examination of the dental morphology of all available extant Australian bat taxa was conducted in order to identify the fossil taxa prior to their analysis in term of species richness and composition. This detailed odontological work provided new diagnostic dental characters for eighteen species and one genus. It also provided additional useful dental characters for three species and seven genera. This odontological analysis allowed the identification of fifteen fossil bat taxa from the Mount Etna deposits, all being representatives of extant bats, and included ten taxa identified to the species level (i.e., Macroderma gigas, Hipposideros semoni, Rhinolophus megaphyllus, Miniopterus schreibersii, Miniopterus australis, Scoteanax rueppellii, Chalinolobus gouldii, Chalinolobus dwyeri, Chalinolobus nigrogriseus and Vespadelus troughtoni) and five taxa identified to the generic level (i.e., Mormopterus, Taphozous, Nyctophilus, Scotorepens and Vespadelus). Palaeoecological analysis of the fossil taxa revealed that, unlike the non-volant mammal taxa, bats have remained essentially stable in terms of species diversity and community membership between the mid-Pleistocene rainforest habitat and the mesic habitat that occurs today in the region. The single major exception is Hipposideros semoni, which went locally extinct at Mount Etna. Additionally, while intensive mining operations resulted in the abandonment of at least one cave that served as a maternity roost in the recent past, the diversity of the Mount Etna bat fauna has not declined since European colonisation. The overall resilience through time of the bat species discussed herein is perhaps due to their unique ecological, behavioural, and physiological characteristics as well as their ability to fly, which have allowed them to successfully adapt to their changing environment. This study highlights the importance of palaeoecological analyses as a tool to gain an understanding of how bats have responded to environmental change in the past and provides valuable information for the conservation of threatened modern species, such as H. semoni.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Purpose – The purpose of this paper is to determine the patterns of transitional employment (TE) aspirations and training and development (T&D) needs of women within local government. Design/methodology/approach – A quantitative survey methodology was used to identify aspirations in a sample of 1,068 employees from the Australian Local Government Association. Findings – Mature-aged women were very interested in continuous learning at work despite their limited formal education. Their training preferences consisted of informal delivery face-to-face or online in the areas of management or administration. Younger women were interested in undertaking university courses, while a minority were interested in blue collar occupations. Practical implications – Through the identification of patterns of TE and T&D aspirations, long term strategies to develop and retain women in local government may be developed. Findings suggest that mature-aged women would benefit from additional T&D to facilitate entry into management and senior administration positions, as well as strategies to facilitate a shift in organizational climate. Social implications – Mature-aged women were found to be a potentially untapped resource for management and senior administrative roles owing to their interest in developing skills in these fields and pursuing TE. Younger women may also benefit from T&D to maintain their capacity during breaks from employment. Encouragement of women in non-traditional areas may also address skill shortages in the local government. Originality/value – Mature-aged women were found to be a potentially untapped resource for management and senior administrative roles owing to their interest in developing skills in these fields and pursuing TE. Younger women may also benefit from T&D to maintain their capacity during breaks from employment. Encouragement of women in non-traditional areas may also address skill shortages in the local government.