953 resultados para Broad mite
Resumo:
The Lesser Grain Borer is a major pest of stored grain with a global distribution. This project has, for the first time recorded this pest throughout broad spatial areas, tens of kilometres from grain production or storage. Statistical analysis revealed that different factors such as ambient temperature and the availability of food resources affect R. dominica differently between different habitats. This suggests that, contrary to the prevailing view, this pest is not solely dependent on stored wheat and can continue to persist throughout a range of habitats. These findings have important management implications for Australia's wheat industry.
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Spatially-explicit modelling of grassland classes is important to site-specific planning for improving grassland and environmental management over large areas. In this study, a climate-based grassland classification model, the Comprehensive and Sequential Classification System (CSCS) was integrated with spatially interpolated climate data to classify grassland in Gansu province, China. The study area is characterized by complex topographic features imposed by plateaus, high mountains, basins and deserts. To improve the quality of the interpolated climate data and the quality of the spatial classification over this complex topography, three linear regression methods, namely an analytic method based on multiple regression and residues (AMMRR), a modification of the AMMRR method through adding the effect of slope and aspect to the interpolation analysis (M-AMMRR) and a method which replaces the IDW approach for residue interpolation in M-AMMRR with an ordinary kriging approach (I-AMMRR), for interpolating climate variables were evaluated. The interpolation outcomes from the best interpolation method were then used in the CSCS model to classify the grassland in the study area. Climate variables interpolated included the annual cumulative temperature and annual total precipitation. The results indicated that the AMMRR and M-AMMRR methods generated acceptable climate surfaces but the best model fit and cross validation result were achieved by the I-AMMRR method. Twenty-six grassland classes were classified for the study area. The four grassland vegetation classes that covered more than half of the total study area were "cool temperate-arid temperate zonal semi-desert", "cool temperate-humid forest steppe and deciduous broad-leaved forest", "temperate-extra-arid temperate zonal desert", and "frigid per-humid rain tundra and alpine meadow". The vegetation classification map generated in this study provides spatial information on the locations and extents of the different grassland classes. This information can be used to facilitate government agencies' decision-making in land-use planning and environmental management, and for vegetation and biodiversity conservation. The information can also be used to assist land managers in the estimation of safe carrying capacities which will help to prevent overgrazing and land degradation.
Resumo:
This project develops and evaluates a model of curriculum design that aims to assist student learning of foundational disciplinary ‘Threshold Concepts’. The project uses phenomenographic action research, cross-institutional peer collaboration and the Variation Theory of Learning to develop and trial the model. Two contrasting disciplines (Physics and Law) and four institutions (two research-intensive and two universities of technology) were involved in the project, to ensure broad applicability of the model across different disciplines and contexts. The Threshold Concepts that were selected for curriculum design attention were measurement uncertainty in Physics and legal reasoning in Law. Threshold Concepts are key disciplinary concepts that are inherently troublesome, transformative and integrative in nature. Once understood, such concepts transform students’ views of the discipline because they enable students to coherently integrate what were previously seen as unrelated aspects of the subject, providing new ways of thinking about it (Meyer & Land 2003, 2005, 2006; Land et al. 2008). However, the integrative and transformative nature of such threshold concepts make them inherently difficult for students to learn, with resulting misunderstandings of concepts being prevalent...
Resumo:
Many fungi, lichens, and bacteria produce xanthones (derivatives of 9H-xanthen-9-one, “xanthone” from the Greek “xanthos”, for “yellow”) as secondary metabolites. Xanthones are typically polysubstituted and occur as either fully aromatized, dihydro-, tetrahydro-, or, more rarely, hexahydro-derivatives. This family of compounds appeals to medicinal chemists because of their pronounced biological activity within a notably broad spectrum of disease states, a result of their interaction with a correspondingly diverse range of target biomolecules. This has led to the description of xanthones as “privileged structures”.(1) Historically, the total synthesis of the natural products has mostly been limited to fully aromatized targets. Syntheses of the more challenging partially saturated xanthones have less frequently been reported, although the development in recent times of novel and reliable methods for the construction of the (polysubstituted) unsaturated xanthone core holds promise for future endeavors. In particular, the fascinating structural and biological properties of xanthone dimers and heterodimers may excite the synthetic or natural product chemist.
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The mineral lulzacite from Saint-Aubin des Chateaux mine, France, with theoretical formula Sr2Fe2+(Fe2+,Mg)2Al4(PO4)4(OH)10 has been studied using a combination of electron microscopy with EDX and vibrational spectroscopic techniques. Chemical analysis shows a Sr, Fe, Al phosphate with minor amounts of Ga, Ba and Mg. Raman spectroscopy identifies an intense band at 990 cm�1 with an additional band at 1011 cm�1. These bands are attributed to the PO3� 4 m1 symmetric stretching mode. The m3 antisymmetric stretching modes are observed by a large number of Raman bands. The Raman bands at 1034, 1051, 1058, 1069 and 1084 together with the Raman bands at 1098, 1116, 1133, 1155 and 1174 cm�1 are assigned to the m3 antisymmetric stretching vibrations of PO3� 4 and the HOPO2� 3 units. The observation of these multiple Raman bands in the symmetric and antisymmetric stretching region gives credence to the concept that both phosphate and hydrogen phosphate units exist in the structure of lulzacite. The series of Raman bands at 567, 582, 601, 644, 661, 673 and 687 cm�1 are assigned to the PO3� 4 m2 bending modes. The series of Raman bands at 437, 468, 478, 491, 503 cm�1 are attributed to the PO3� 4 and HOPO2� 3 m4 bending modes. No Raman bands of lulzacite which could be attributed to the hydroxyl stretching unit were observed. Infrared bands at 3511 and 3359 cm�1 are ascribed to the OH stretching vibration of the OH units. Very broad bands at 3022 and 3299 cm�1 are attributed to the OH stretching vibrations of water. Vibrational spectroscopy offers insights into the molecular structure of the phosphate mineral lulzacite.
Resumo:
We have studied the molecular structure of the mineral glaucocerinite (Zn,Cu)5Al3(SO4)1.5(OH)16�9(H2O) using a combination of Raman and infrared spectroscopy. The mineral is one of the hydrotalcite supergroup of natural layered double hydroxides. The Raman spectrum is characterised by an intense Raman band at 982 cm�1 with a low intensity band at 1083 cm�1. These bands are attributed to the sulphate symmetric and antisymmetric stretching mode. The infrared spectrum is quite broad with a peak at 1020 cm�1. A series of Raman bands at 546, 584, 602, 625 and 651 cm�1 are assigned to the m4 (SO4)2� bending modes. The observation of multiple bands provides evidence for the reduction in symmetry of the sulphate anion from Td to C2v or even lower symmetry. The Raman band at 762 cm�1 is attributed to a hydroxyl deformation mode associated with AlOH units. Vibrational spectroscopy enables aspects of the molecular structure of glaucocerinite to be determined.
Resumo:
We have studied the hydrated hydroxyl silicate mineral inesite of formula Ca2(Mn,Fe)7Si10O28(OH)⋅5H2O using a combination of scanning electron microscopy with EDX and Raman and infrared spectroscopy. SEM analysis shows the mineral to be a pure monomineral with no impurities. Semiquantitative analysis shows a homogeneous phase, composed by Ca, Mn2+, Si and P, with minor amounts of Mg and Fe. Raman spectrum shows well resolved component bands at 997, 1031, 1051, and 1067 cm-1 attributed to a range of SiO symmetric stretching vibrations of [Si10O28] units. Infrared bands found at 896, 928, 959 and 985 cm-1 are attributed to the OSiO antisymmetric stretching vibrations. An intense broad band at 653 cm-1 with shoulder bands at 608, 631 and 684 cm-1 are associated with the bending modes of the OSiO units of the 6- and 8-membered rings of the [Si10O28] units. The sharp band at 3642 cm-1 with shoulder bands at 3612 and 3662 cm-1 are assigned to the OH stretching vibrations of the hydroxyl units. The broad Raman band at 3420 cm-1 with shoulder bands at 3362 and 3496 cm-1 are assigned to the water stretching vibrations. The application of vibrational spectroscopy has enabled an assessment of the molecular structure of inesite to be undertaken.
Resumo:
The mineral beraunite from Boca Rica pegmatite in Minas Gerais with theoretical formula Fe2+Fe5 3+(PO4)4(OH)5⋅4H2O has been studied using a combination of electron microscopy with EDX and vibrational spectroscopic techniques. Raman spectroscopy identifies an intense band at 990 cm-1 and 1011 cm-1. These bands are attributed to the PO4 3- v, symmetric stretching mode. The m3 antisymmetric stretching modes are observed by a large number of Raman bands. The Raman bands at 1034, 1051, 1058, 1069 and 1084 together with the Raman bands at 1098, 1116, 1133, 1155 and 1174 cm-1 are assigned to the m3 antisymmetric stretching vibrations of PO4 3- and the HOPO3 2- units. The observation of these multiple Raman bands in the symmetric and antisymmetric stretching region gives credence to the concept that both phosphate and hydrogen phosphate units exist in the structure of beraunite. The series of Raman bands at 567, 582,601, 644, 661, 673, and 687 cm-1 are assigned to the PO4 3- v2 bending modes. The series of Raman bands at 437, 468, 478, 491, 503 cm-1 are attributed to the PO4 3- and OPO3 2- v4 bending modes. No Raman bands of beraunite which could be attributed to the hydroxyl stretching unit were observed. Infrared bands at 3511 and 3359 cm-1 are ascribed to the OH stretching vibration of the OH units. Very broad bands at 3022 and 3299 cm-1 are attributed to the OH stretching vibrations of water. Vibrational spectroscopy offers insights into the molecular structure of the phosphate mineral beraunite.
Resumo:
The concept of affordance has different interpretations in the field of Human-Computer Interaction (HCI). However, its treatment has been merely as a one-to-one relationship between a user and a technology. We believe that a broader view of affordances is needed which encompasses social and cultural aspects of our everyday life. We propose an interaction-centered view of affordance that can be useful for developing better understandings of designed artefacts. An interaction-centered view of affordance suggests that affordance is an interpretative relationship between users and the technology that emerges during the users' interaction with the technology in the lived environments. We distinguish two broad classes of affordances: affordance in Information and affordance in Articulation. Affordance in information refers to users' understanding of a technology based on their semantic and syntactic interpretation; and affordance in articulation refers to users' interpretations about the use of the technology. We also argue that the notion of affordance should be treated at two levels: at the 'artefact level' and at the 'practice level'. Consequently, we provide two examples to demonstrate our arguments.
Resumo:
The position(s) of carbon-carbon double bonds within lipids can dramatically affect their structure and reactivity and thus has a direct bearing on biological function. Commonly employed mass spectrometric approaches to the characterization of complex lipids, however, fail to localize sites of unsaturation within the molecular structure and thus cannot distinguish naturally occurring regioisomers. In a recent communication \[Thomas, M. C.; Mitchell, T. W.; Blanksby, S. J. J. Am. Chem. Soc. 2006, 128, 58-59], we have presented a new technique for the elucidation of double bond position in glycerophospholipids using ozone-induced fragmentation within the source of a conventional electrospray ionization mass spectrometer. Here we report the on-line analysis, using ozone electrospray mass spectrometry (OzESI-MS), of a broad range of common unsaturated lipids including acidic and neutral glycerophospholipids, sphingomyelins, and triacylglycerols. All lipids analyzed are found to form a pair of chemically induced fragment ions diagnostic of the position of each double bond(s) regardless of the polarity, the number of charges, or the adduction (e.g., \[M - H](-), \[M - 2H](2-), \[M + H](+), \[M + Na](+), \[M + NH4](+)). The ability of OzESI-MS to distinguish lipids that differ only in the position of the double bonds is demonstrated using the glycerophosphocholine standards, GPCho(9Z-18:1/9Z-18:1) and GPCho(6Z-18:1/6Z-18:1). While these regioisomers cannot be differentiated by their conventional tandem mass spectra, the OzESI-MS spectra reveal abundant fragment ions of distinctive mass-to-charge ratio (m/z). The approach is found to be sufficiently robust to be used in conjunction with the m/z 184 precursor ion scans commonly employed for the identification of phosphocholine-containing lipids in shotgun lipidomic analyses. This tandem OzESI-MS approach was used, in conjunction with conventional tandem mass spectral analysis, for the structural characterization of an unknown sphingolipid in a crude lipid extract obtained from a human lens. The OzESI-MS data confirm the presence of two regioisomers, namely, SM(d18:0/15Z-24:1) and SM(d18:0/17Z-24:1), and suggest the possible presence of a third isomer, SM(d18:0/19Z-24:1), in lower abundance. The data presented herein demonstrate that OzESI-MS is a broadly applicable, on-line approach for structure determination and, when used in conjunction with established tandem mass spectrometric methods, can provide near complete structural characterization of a range of important lipid classes. As such, OzESI-MS may provide important new insight into the molecular diversity of naturally occurring lipids.
Resumo:
Ions formed from lipids during electrospray ionization of crude lipid extracts have been mass-selected within a quadrupole linear ion trap mass spectrometer and allowed to react with ozone vapor. Gas-phase ion-molecule reactions between unsaturated lipid ions and ozone are found to yield two primary product ions for each carbon-carbon double bond within the molecule. The mass-to-charge ratios of these chemically induced fragments are diagnostic of the position of unsaturation within the precursor ion. This novel analytical technique, dubbed ozone-induced dissociation (OzID), can be applied both in series and in parallel with conventional collision-induced dissociation (CID) to provide near-complete structural assignment of unknown lipids within complex mixtures without prior fractionation or derivatization. In this study, OzID is applied to a suite of complex lipid extracts from sources including human lens, bovine kidney, and commercial olive oil, thus demonstrating the technique to be applicable to a broad range of lipid classes including both neutral and acidic glycerophospholipids, sphingomyelins, and triacylglycerols. Gas-phase ozonolysis reactions are also observed with different types of precursor ions including \[M + H](+), \[M + Li](+), \[M + Na](+), and \[M H](-): in each case yielding fragmentation data that allow double bond position to be unambiguously assigned. Within the human lens lipid extract, three sphingomyelin regioisomers, namely SM(d18:0/15Z-24:1), SM(d18:0/17Z-24:1), and SM(d18:0/19Z-24:1), and a novel phosphatidylethanolamine alkyl ether, GPEtn(11Z-18:1e/9Z18:1), are identified using a combination of CID and OzID. These discoveries demonstrate that lipid identification based on CID alone belies the natural structural diversity in lipid biochemistry and illustrate the potential of OzID as a complementary approach within automated, high-throughput lipid analysis protocols.
Resumo:
There are a large number of boron-containing minerals, of which vonsenite is one. Some discussion about the molecular structure of vonsenite exists in the literature. Whether water is involved in the structure is ill-determined. The molecular structure of vonsenite has been assessed by the combination of Raman and infrared spectroscopy. The Raman spectrum is characterized by two intense broad bands at 997 and 1059 cm−1 assigned to the BO stretching vibrational mode. A series of Raman bands in the 1200–1500 cm−1 spectral range are attributed to BO antisymmetric stretching modes and in-plane bending modes. The infrared spectrum shows complexity in this spectral range. No Raman spectrum of water in the OH stretching region could be obtained. The infrared spectrum shows a series of overlapping bands with bands identified at 3037, 3245, 3443, 3556, and 3614 cm−1. It is important to understand the structure of vonsenite in order to form nanomaterials based on its structure. Vibrational spectroscopy enables a better understanding of the structure of vonsenite.
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Within Human-Computer Interaction (HCI) and Computer Supported Cooperative Work (CSCW) research, the notion of technologically-mediated awareness is often used for allowing relevant people to maintain a mental model of activities, behaviors and status information about each other so that they can organize and coordinate work or other joint activities. The initial conceptions of awareness focused largely on improving productivity and efficiency within work environments. With new social, cultural and commercial needs and the emergence of novel computing technologies, the focus of technologically-mediated awareness has extended from work environments to people’s everyday interactions. Hence, the scope of awareness has extended from conveying work related activities to people’s emotions, love, social status and other broad range of aspects. This trend of conceptualizing HCI design is termed as experience-focused HCI. In my PhD dissertation, designing for awareness, I have reported on how we, as HCI researchers, can design awareness systems from experience-focused HCI perspective that follow the trend of conveying awareness beyond the task-based, instrumental and productive needs. Within the overall aim to design for awareness, my research advocates ethnomethodologically-informed approaches for conceptualizing and designing for awareness. In this sense, awareness is not a predefined phenomenon but something that is situated and particular to a given environment. I have used this approach in two design cases of developing interactive systems that support awareness beyond task-based aspects in work environments. In both the cases, I have followed a complete design cycle: collecting an in-situ understanding of an environment, developing implications for a new technology, implementing a prototype technology to studying the use of the technology in its natural settings.
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Engineering Your Future: An Australasian Guide, 2nd Edition, is the ideal textbook for undergraduate students beginning their engineering studies. Building on the success of the popular 1st edition, this new edition continues the strong and practical emphasis on skills that are essential for engineering problem-solving and design. Numerous topical and locally focused examples of projects across the broad range of engineering disciplines help to graphically demonstrate the role and responsibilities of a professional engineer. Themes of sustainability, ethical practice and effective communication are constant throughout the text. In addition, its many exercises and project activities will encourage students to put key engineering principles and skills into practice.
Resumo:
Two native copper-containing amine oxidases (EC 1.4.3.21) have been isolated from Rhodococcus opacus and reveal phenotypic plasticity and catalytic activity with respect to structurally diverse natural and synthetic amines. Altering the amine growth substrate has enabled tailored and targeted oxidase upreg-ulation, which with subsequent treatment by precipitation, ion exchange and gel filtration, achieved a 90–150 fold purification. MALDI-TOF mass spectrometric and genomic analysis has indicated multiple gene activation with complex biodegradation pathways and regulatory mechanisms. Additional post-purification characterisation has drawn on the use of carbonyl reagent and chelating agent inhibitors. Michaelis–Menten kinetics for common aliphatic and aromatic amine substrates and several structural analogues demonstrated a broad specificity and high affinity with Michaelis constants (K M) ranging from 0.1 to 0.9 mM for C 1 –C 5 aliphatic mono-amines and <0.2 mM for a range of aromatic amines. Potential exploitation of the enzymatic versatility of the two isolated oxidases in biosensing and bioprocessing is discussed.