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1
Loaiciga, Hugo A., i Miguel A. Mariño. "The inverse problem for confined aquifer flow: Identification and estimation with extensions". Water Resources Research 23, nr 1 (styczeń 1987): 92–104. http://dx.doi.org/10.1029/wr023i001p00092.
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De Sarkar, Tanmay. "The prevalence of web browser extensions use in library services: an exploratory study". Electronic Library 33, nr 3 (1.06.2015): 334–54. http://dx.doi.org/10.1108/el-04-2013-0063.
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Purpose – The paper aims to present an outline how libraries are harnessing browser extensions to provide an easy and convenient access to library resources and services. Investigating the features, purposes of use and types of browser extensions prevalent among libraries in different regions, the paper seeks to measure the degree of implementation of browser extensions. Design/methodology/approach – Stratified sampling method was followed to select academic libraries, and convenient sampling method was applied to select public libraries from four continents – Asia, Oceania, Europe and North America. Two-step web content analysis was applied to gather data along the select dimensions. Findings – The study contributes to the recent advances in application of browser extension with numerous examples focussing on the relevance of different approaches adopted by the libraries. Providing a framework of proportionate implementation along checkpoints, the study also highlights degree of acceptance of browser extension among libraries in different regions. Research limitations/implications – The investigation was restricted to libraries having English websites and confined to four continents only. This study aims at improving understanding among the librarians about the intended use and application of browser extension and helping them benchmark their effort in support of education, research and training. The current investigation expands the scope of future research on remaining regions and website whose contents are in non-English language to attain a broader perspective of its implementation. Originality/value – The article may guide library professionals to use, develop and promote the implementation of browser extension in libraries. The checkpoints used here may serve as bedrock for framing questionnaire and interview schedule for conducting future research examining users’ perception of browser extension in the context of library resources and usage pattern, to fully comprehend its practicability and usefulness.
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Otto, K. N., i E. K. Antonsson. "Extensions to the Taguchi Method of Product Design". Journal of Mechanical Design 115, nr 1 (1.03.1993): 5–13. http://dx.doi.org/10.1115/1.2919325.
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The Taguchi method of product design is an experimental approximation to minimizing the expected value of target variance for certain classes of problems. Taguchi’s method is extended to designs which involve variables each of which has a range of values all of which must be satisfied (necessity), and designs which involve variables each of which has a range of values any of which might be used (possibility). Tuning parameters, as a part of the design process, are also demonstrated within Taguchi’s method. The method is also extended to solve design problems with constraints, invoking the methods of constrained optimization. Finally, the Taguchi method uses a factorial method to search the design space, with a confined definition of an optimal solution. This is compared with other methods of searching the design space and their definitions of an optimal solution.
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Morapedi, Setumile. "Passive constructions in Setswana". JULACE: Journal of the University of Namibia Language Centre 3, nr 1 (30.06.2018): 38–52. http://dx.doi.org/10.32642/julace.v3i1.1374.
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The paper analyses passive constructions in Setswana from morpho-syntactic view point, showing that the suffixation of a passive morpheme to the verb reduces the argument structure of the verb. Previous studies carried out in Setswana verbal suffixes have confined their investigations to these morphemes as elements of morphology but have failed to observe that these affixes overlap into syntax. Chebanne (1996) observes that in Setswana, verbal extensions can combine with a single verbal base but fail to observe the overlap into syntax. Further, the studies do not give any insight in the features that Setswana shares with other Bantu languages. The passive construction in Setswana, like in other Bantu languages, is a bit complex in the sense that the verbal extension –iw brings into effect the dropping of the subject, and the object becomes the grammatical subject, thus rendering the transitive verb, such as, apaya ‘cook’ intransitive. Conversely, other derivational suffixes, such as applicative and causative, increase the verb’s arguments by two. For instance, the suffixation of the verbal suffix –el suggests an entity carrying out the action and somebody benefiting. The paper also compares passive with other verbal extensions such as neuter, applicative, causatives and reciprocals. It shows that while the passive occurs with most verbs and other verbal extensions, such as, applicative or causative suffixes, the neuter is rigid in occurring with other verbal extensions. The paper also appeals to Lexical Mapping Theory, whose role is to constrain mapping relations between thematic roles, such as an agent or patient and the corresponding grammatical functions, such as the subject, patient and oblique that have been subcategorized for by predicates
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Mazharimousavi, S. Habib, Z. Amirabi i M. Halilsoy. "Thin-shell wormholes in (2 + 1)-dimensional Einstein-scalar theory". Modern Physics Letters A 32, nr 10 (27.03.2017): 1750064. http://dx.doi.org/10.1142/s021773231750064x.
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We present an infinite class of one-parameter scalar field extensions to the Bañados, Teitelboim and Zanelli (BTZ) black hole in 2 + 1 dimensions. By virtue of the scalar charge, the thin-shell wormhole supported by a linear fluid at the throat becomes stable against linear perturbations. More interestingly, we provide an example of thin-shell wormhole which is strictly stable in the sense that it is confined in between two classically intransmissible potential barriers.
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DU, ZHUO, XIN-LEI FAN, QIN YANG i CHENG-MING TIAN. "Host and geographic range extensions of Melanconiella, with a new species M. cornuta in China". Phytotaxa 327, nr 3 (10.11.2017): 252. http://dx.doi.org/10.11646/phytotaxa.327.3.4.
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Members of Melanconiella are opportunistic pathogens and endophytic fungi, and have been found to confined so far, on the collection of host family Betulaceae. Moreover, two fresh specimens associated with canker and dieback of Cornus controversa and Juglans regia collected in Shaanxi, China were found as distinct and new species of Melanconiella, based on morphological and multi-gene, combined, phylogenetic analyses (ITS, LSU, rpb2 and tef1-α). Results also revealed the host and geographic range extensions of this genus. Melanconiella cornuta sp. nov. is introduced with an illustrated account and differs from similar species in its host association and multigene phylogeny.
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Cretu, Nicolae, Mihail-Ioan Pop i Hank Steve Andia Prado. "Some Theoretical and Experimental Extensions Based on the Properties of the Intrinsic Transfer Matrix". Materials 15, nr 2 (10.01.2022): 519. http://dx.doi.org/10.3390/ma15020519.
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The work approaches new theoretical and experimental studies in the elastic characterization of materials, based on the properties of the intrinsic transfer matrix. The term ‘intrinsic transfer matrix’ was firstly introduced by us in order to characterize the system in standing wave case, when the stationary wave is confined inside the sample. An important property of the intrinsic transfer matrix is that at resonance, and in absence of attenuation, the eigenvalues are real. This property underlies a numerical method which permits to find the phase velocity for the longitudinal wave in a sample. This modal approach is a numerical method which takes into account the eigenvalues, which are analytically estimated for simple elastic systems. Such elastic systems are characterized by a simple distribution of eigenmodes, which may be easily highlighted by experiment. The paper generalizes the intrinsic transfer matrix method by including the attenuation and a study of the influence of inhomogeneity. The condition for real eigenvalues in that case shows that the frequencies of eigenmodes are not affected by attenuation. For the influence of inhomogeneity, we consider a case when the sound speed is varying along the layer’s length in the medium of interest, with an accompanying dispersion. The paper also studies the accuracy of the method in estimating the wave velocity and determines an optimal experimental setup in order to reduce the influence of frequency errors.
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Streiffer, S. K., i D. D. Fong. "Phase Transitions in Nanoscale Ferroelectric Structures". MRS Bulletin 34, nr 11 (listopad 2009): 832–37. http://dx.doi.org/10.1557/mrs2009.233.
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AbstractOver decades of effort, investigations of the intrinsic phase transition behavior of nanoscale ferroelectric structures have been greatly complicated by materials processing variations and by the common and uncontrolled occurrence of spacecharge, which interacts directly with the polarization and can obscure fundamental behavior. These challenges have largely been overcome, and great progress in understanding the details of this class of phase transitions has been made, largely based on advances in the growth of high-quality, epitaxial ferroelectric films and in the theory and simulation of ferroelectricity. Here we will discuss recent progress in understanding the ferroelectric phase transition in a particular class of model systems: nanoscale perovskite thin-film heterostructures. The outlook for ferroelectric technology based on these results is promising, and extensions to laterally confined nanostructures will be described.
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Schulte, Reinhard W., i Tianfang Li. "Innovative Strategies for Image-Guided Proton Treatment of Prostate Cancer". Technology in Cancer Research & Treatment 5, nr 2 (kwiecień 2006): 91–100. http://dx.doi.org/10.1177/153303460600500203.
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Proton beam therapy has a proven track record of treating non-metastatic prostate cancer with excellent disease-free survival results when using homogeneous doses between 75 and 82 CGE (Cobalt Gray Equivalent) to the prostate target volume. In clinically organ-confined prostate cancer, it may be possible, in principle, to further improve outcomes by reducing the margins of the high-dose planning target volume to the gross tumor volume and by covering the clinical target volume with a dose sufficient to control microscopic extensions of the tumor. This would allow further dose escalation without increasing the risk of acute and late effects. In this paper, we undertake a careful review of existing histopathological data that support this view and discuss technical possibilities to this approach utilizing the highly conformal characteristics of proton beams and combining them with modern 4D imaging and treatment techniques.
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Donaire, Manuel, José María Muñoz-Castañeda, Luis Miguel Nieto i Marcos Tello-Fraile. "Field Fluctuations and Casimir Energy of 1D-Fermions". Symmetry 11, nr 5 (7.05.2019): 643. http://dx.doi.org/10.3390/sym11050643.
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We investigate the self-adjoint extensions of the Dirac operator of a massive one-dimensional field of mass m confined in a finite filament of length L. We compute the spectrum of vacuum fluctuations of the Dirac field under the most general dispersionless boundary conditions. We identify its edge states in the mass gap within a set of values of the boundary parameters, and compute the Casimir energy of the discrete normal modes. Two limit cases are considered, namely, that of light fermions with m L ≪ 1 , and that of heavy fermions for which m L ≫ 1 . It is found that both positive and negative energies are obtained for different sets of values of the boundary parameters. As a consequence of our calculation we demonstrate that the sign of the quantum vacuum energy is not fixed for exchange-symmetric plates (parity-invariant configurations), unlike for electromagnetic and scalar fields.
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Steed, Jennifer L., i Chandra R. Bhat. "On Modeling Departure-Time Choice for Home-Based Social/Recreational and Shopping Trips". Transportation Research Record: Journal of the Transportation Research Board 1706, nr 1 (styczeń 2000): 152–59. http://dx.doi.org/10.3141/1706-18.
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The existing literature on departure-time choice has primarily focused on work trips. Departure-time choice for nonwork trips, which constitute an increasingly large proportion of urban trips, is examined. Discrete choice models are estimated for home-based social/recreational and home-based shopping trips using the 1996 activity survey data collected in the Dallas—Fort Worth metropolitan area. The effects of individual and household sociodemographics, employment attributes, and trip characteristics on departure-time choice are presented and discussed. The results indicate that departure-time choice for social/recreational trips and shopping trips is determined for the most part by individual or household sociodemographics and employment characteristics, and to a lesser extent by trip level-of-service characteristics. This suggests that departure times for social/recreational and shopping trips are not as flexible as one might expect and are confined to certain times of day because of overall scheduling constraints. Future methodological and empirical extensions of the current research are identified.
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Kholmetskii, Alexander L., Tolga Yarman, Ozan Yarman i Metin Arik. "Mössbauer experiments in a rotating system and physical interpretation of their results". Journal of the Belarusian State University. Physics, nr 2 (21.05.2021): 34–43. http://dx.doi.org/10.33581/2520-2243-2021-2-34-43.
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We discuss the results of modern Mössbauer experiments in a rotating system, which show the presence of an extra energy shift between the emitted and absorbed resonant radiation in addition to the relativistic energy shift of the resonant lines due to the time dilation effect in the co-rotating source and absorber with different radial coordinates. We analyse the available attempts to explain the origin of the extra energy shift, which include some extensions of special theory of relativity with hypothesis about the existence of limited acceleration in nature, with hypothesis about a so-called «time-dependent Doppler effect», as well as in the framework of the general theory of relativity under re-analysis of the metric effects in the rotating system, which is focused to the problem of correct synchronisation of clocks in a rotating system with a laboratory clock. We show that all such attempts remain unsuccessful until the moment, and we indicate possible ways of solving this problem, which should combine metric effects in rotating systems with quantum mechanical description of resonant nuclei confined in crystal cells.
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Adams, Paul Channing. "A Reconsideration of Personal Boundaries in Space‐Time". Annals of the Association of American Geographers 85, nr 2 (czerwiec 1995): 267–85. http://dx.doi.org/10.1111/j.1467-8306.1995.tb01793.x-i1.
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AbstractAn appropriate image of the person for geographers is an entity with fluctuating boundaries that reach through space and time in constantly changing patterns. Such extensions through space and time are not merely “internal” or psychological states of being in the world; they are integral to economic, political, and cultural processes. Human extensibility is fundamental to the ongoing processes of social structuration in which social practices are constitutive of social structures and social structures constrain persons and practices. Whereas the body is a point‐entity located at a particular space‐time, important aspects of personhood are not confined to this point entity. Authority depends on ranges of sensation, knowledge, and action through diverse communication systems. While extensibility is partly determined by the body, as categorized by society, the distinction between presence and absence can be considered as a gradation rather than a binary opposition. Extensibility transcends the body, allowing a person to overcome social and physical limitations and to participate in distant social contexts which affect his or her personal situation and shape social processes.
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Al-Hashimi, M. H., i U. J. Wiese. "Self-adjoint extensions for confined electrons: From a particle in a spherical cavity to the hydrogen atom in a sphere and on a cone". Annals of Physics 327, nr 11 (listopad 2012): 2742–59. http://dx.doi.org/10.1016/j.aop.2012.06.006.
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BAO, SHOU-SHAN, XUE GONG, ZONG-GUO SI i YU-FENG ZHOU. "FOURTH GENERATION MAJORANA NEUTRINO, DARK MATTER AND HIGGS PHYSICS". International Journal of Modern Physics A 29, nr 02 (20.01.2014): 1450010. http://dx.doi.org/10.1142/s0217751x14500109.
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We consider extensions of the standard model with fourth generation fermions (SM4) in which extra symmetries are introduced such that the transitions between the fourth generation fermions and the ones in the first three generations are forbidden. In these models, the stringent lower bounds on the masses of fourth generation quarks from direct searches can be relaxed, and the lightest fourth neutrino is allowed to be stable and light enough to trigger the Higgs boson invisible decay. In addition, the fourth Majorana neutrino can be a subdominant but highly detectable dark matter component. We perform a global analysis of the current Large Hadron Collider (LHC) data on the Higgs production and decay in this type of SM4. The results show that the mass of the lightest fourth Majorana neutrino is confined in the range ~41–59 GeV. Within the allowed parameter space, the predicted effective cross-section for spin-independent DM–nucleon scattering is ~3×10-48–6×10-46 cm 2, which is close to the current XENON100 upper limit and is within the reach of the XENON1T experiment in the near future. The predicted spin-dependent cross sections can also reach ~8×10-40 cm 2.
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Li, Yizeng, Lingxing Yao, Yoichiro Mori i Sean X. Sun. "On the energy efficiency of cell migration in diverse physical environments". Proceedings of the National Academy of Sciences 116, nr 48 (12.11.2019): 23894–900. http://dx.doi.org/10.1073/pnas.1907625116.
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In this work, we explore fundamental energy requirements during mammalian cell movement. Starting with the conservation of mass and momentum for the cell cytosol and the actin-network phase, we develop useful identities that compute dissipated energies during extensions of the cell boundary. We analyze 2 complementary mechanisms of cell movement: actin-driven and water-driven. The former mechanism occurs on 2-dimensional cell-culture substrate without appreciable external hydraulic resistance, while the latter mechanism is prominent in confined channels where external hydraulic resistance is high. By considering various forms of energy input and dissipation, we find that the water-driven cell-migration mechanism is inefficient and requires more energy. However, in environments with sufficiently high hydraulic resistance, the efficiency of actin-polymerization-driven cell migration decreases considerably, and the water-based mechanism becomes more efficient. Hence, the most efficient way for cells to move depends on the physical environment. This work can be extended to higher dimensions and has implication for understanding energetics of morphogenesis in early embryonic development and cancer-cell metastasis and provides a physical basis for understanding changing metabolic requirements for cell movement in different conditions.
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Amiridis, V., D. Melas, D. S. Balis, A. Papayannis, D. Founda, E. Katragkou, E. Giannakaki, R. E. Mamouri, E. Gerasopoulos i C. Zerefos. "Aerosol lidar observations and model calculations of the planetary boundary layer evolution over Greece, during the March 2006 total solar eclipse". Atmospheric Chemistry and Physics Discussions 7, nr 5 (14.09.2007): 13537–60. http://dx.doi.org/10.5194/acpd-7-13537-2007.
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Abstract. An investigation of the Planetary Boundary Layer (PBL) height evolution over Greece, during the solar eclipse of 29 March 2006, is presented. Ground based observations were carried out using lidar detection and ranging devices (Lidars) and ground meteorological instruments, to estimate the height of the Mixing Layer (ML) before, during and after the solar eclipse in Northern and Southern parts of Greece exhibiting different sun obscuration. Data demonstrate that the solar eclipse has induced a decrease of the PBL height, indicating a suppression of turbulence activity similar to that during the sunset hours. The changes in PBL height were associated with a very shallow entrainment zone, indicating a significant weakening of the penetrative convection. Heat transfer was confined to a thinner layer above ground. The thickness of the entrainment zone exhibited its minimum during the maximum of the eclipse, demonstrative of turbulence mechanisms suppression at that time. Model estimations of the PBL evolution were additionally conducted using the Comprehensive Air Quality Model with extensions (CAMx) coupled with the Weather Research and Forecasting model (WRF). Model diagnosed PBL height decrease during the solar eclipse due to vertical transport decay, in agreement with the experimental findings; vertical profiles of atmospheric particles and gaseous species showed an important vertical mixing attenuation.
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Amiridis, V., D. Melas, D. S. Balis, A. Papayannis, D. Founda, E. Katragkou, E. Giannakaki, R. E. Mamouri, E. Gerasopoulos i C. Zerefos. "Aerosol Lidar observations and model calculations of the Planetary Boundary Layer evolution over Greece, during the March 2006 Total Solar Eclipse". Atmospheric Chemistry and Physics 7, nr 24 (20.12.2007): 6181–89. http://dx.doi.org/10.5194/acp-7-6181-2007.
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Abstract. An investigation of the Planetary Boundary Layer (PBL) height evolution over Greece, during the solar eclipse of 29 March 2006, is presented. Ground based observations were carried out using lidar detection and ranging devices and ground meteorological instruments, to estimate the height of the mixing layer (ML) before, during and after the solar eclipse in northern and southern parts of Greece exhibiting different sun obscuration. Data demonstrate that the solar eclipse has induced a decrease of the PBL height, indicating a suppression of turbulence activity similar to that during the sunset hours. The changes in PBL height were associated with a very shallow entrainment zone, indicating a significant weakening of the penetrative convection. Heat transfer was confined to a thinner layer above the ground. The thickness of the entrainment zone exhibited its minimum during the maximum of the eclipse, demonstrative of turbulence mechanisms suppression at that time. Model estimations of the PBL evolution were additionally conducted using the Comprehensive Air Quality Model with extensions (CAMx) coupled with the Weather Research and Forecasting model (WRF). Model-diagnosed PBL height decrease during the solar eclipse due to vertical transport decay, in agreement with the experimental findings; vertical profiles of atmospheric particles and gaseous species showed an important vertical mixing attenuation.
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Singh, Rajendra. "How to Live with External Evidence in Phonology: A Note on the Challenge of Interference". Canadian Journal of Linguistics/Revue canadienne de linguistique 33, nr 4 (grudzień 1988): 423–29. http://dx.doi.org/10.1017/s0008413100013219.
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As far as phonology and morphology are concerned, the available evidence indicates that the role of L1 in shaping interlanguage is confined to those of its rules that are needed to account for its global alternations, alternations that are independent of its morphology (cf. Cearly 1974, Dressler 1985, Kilbury 1981, Singh and Ford 1982, 1987, Singh and Martohardjono 1989, Wode 1978, and Wurzel 1977, among others). The rules needed to account for the local, morphologically dependent alternations of L1 or the ones needed to account for its word-formation processes do not play such a role. Interference, in other words, can be caused only by across-the-board phonological rules of L1. So-called morphophonemic rules of L1 do not cause it, and morphological interference from L1 seems not to exist as word-formation errors in intermorphology are the results of illegal extensions of L2 word-formation rules (cf. Singh 1989 and Singh and Martohardjono 1989). The purpose of this note is to critically examine the accounts contemporary theories of phonology provide of this state of affairs and to argue that the account provided by the sort of theory proposed in Ford and Singh (1983, 1985a, 1985b) and Singh and Ford (1982, 1987) is the most satisfactory one.
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Boano, Giovanni, Fabio Perco, Marco Pavia i Natale Emilio Baldaccini. "[Columba livia domestic breed, invasive entity also alien for Italy]". Rivista Italiana di Ornitologia 88, nr 2 (18.06.2019): 3–10. http://dx.doi.org/10.4081/rio.2018.356.
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[The Rock Dove (Columba livia) is a polytypic species originally confined to coastal and inland cliffs of western Palaearctic and northern Ethiopian regions and to those of Indian subcontinent. The present distribution is confused by extensions of range through hybridization with feral stock, which have determined its diffusion in geographical areas and environments that are very different and distant from the original ones, with a naturalized distribution now virtually cosmopolitan. Besides a substantial number of domestic breeds reared and maintained in this state, Columba livia is now represented by the original wild populations, generally in decline, and by feral populations, originated from abandoned or escaped domestic individuals. These populations developed above all, but no exclusively, in the cities, starting from the end of the XVIII century, with a further significant increase during the second post-war period, In this work, after having examined and discussed the distribution of the species resulting from the Pleistocene fossil findings and from the historical ornithological literature, we advance the hypothesis that wherever there are free-living populations showing phenotypic, biometric or genetic characteristics different from the wild morphotype, it is legitimate to consider these populations as an alien complex of domestic origin, to be controlled by culling and, when possible, eradicated. On the side-lines of this work, the Authors hope for a reconsideration of Italian names of this species.]
[Article in Italian]
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GERSHWIN, LISA-ANN. "Malo kingi: A new species of Irukandji jellyfish (Cnidaria: Cubozoa: Carybdeida), possibly lethal to humans, from Queensland, Australia". Zootaxa 1659, nr 1 (11.12.2007): 55–68. http://dx.doi.org/10.11646/zootaxa.1659.1.2.
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Irukandji stings may be lethal to humans, and yet, until late 2005, only one of the many suspected Irukandji stingers had been formally named and classified. This paper describes Malo kingi, n. sp., which is apparently responsible for a recent fatality. This species differs from all other cubozoans in having halo-like rings of tissue encircling the tentacles, with club-shaped Type 4 microbasic mastigophores inserted end-on around the periphery of the rings. It further differs from its only current congener, Malo maxima, in having: a much smaller, more rounded body; different tubule winding patterns in the undischarged nematocysts; spines confined to the distal-most portion of the shaft in the discharged nematocysts; relatively broader pedalia; somewhat less well defined rhopalial horns; and perradial lappets with a greater number of nematocyst warts and nipple-like terminal extensions. Much additional work is needed to better understand the general biology of this and other dangerous species so as to prevent further fatalities, debilitating illnesses, and threats to the tourism industry resulting from the marine stinger problem. Treatment of envenomations, management issues regarding sting prevention, and the related implications for tourism, all rely on being able to consistently and accurately identify public health hazards. The need still exists for an aggressive awareness campaign aimed at residents and visitors regarding education and prevention of Irukandji stings.
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Olusa, T. A. O., C. M. Murray i H. M. S. Davies. "Radiographic assessment of the equine carpal joint under incremental loads and during flexion". Comparative Exercise Physiology 15, nr 5 (10.12.2019): 359–70. http://dx.doi.org/10.3920/cep180044.
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Non-physiologic loading of the carpal bones is believed to result in osteochondral fractures, ligament rupture and axial instability in the equine forelimb; however, the mechanism of carpal damage due to non-physiologic loading of the carpus is largely unknown. To investigate carpal stability (alignment and direction of carpal bones’ movement) under load and during flexion, some previously described carpal parameters were measured on radiographs obtained from 24 equine cadaver limbs (aged 10.71±4.15 years). The limbs were transected at the antebrachial midshaft, axially loaded in a commercial press and serially radiographed under a range of incremental loads (extension) and 2 flexion positions. The extensions were measured by a 10° decrease in the dorsal fetlock angle (DFA) from 160° to 110° (DFA160 to DFA110) using the jacking system of the press; and flexions at palmar carpal angle of 45° and 90° (PCA45 and PCA90). As loading increased from DFA160 to DFA110 there was a progressive significant increase in Third Carpal bone Palmar Facet Angle (C3PalFCA: 86.46±2.54° to 88.60±2.51°) but a decrease in Dorsal Carpal Angle (DCA: 173.03±3.47° to 159.65±4.09°); Medial Carpal Angle (MCA: 186.31±1.90° to 184.61±2.26°); and Groove width of the Cr-Ci intercarpal ligament (GW.Cr-Ci ICL: 9.35±1.20° to 8.83±1.13°) while no significant differences were observed for Distal Radial Slope Carpal Angle (DRSCA) and Intermediate carpal bone Proximal Tuberosity-Radial Angle (CiPxTRA). A generalised medio-distal directional displacement in the carpal bones’ movement were observed. In conclusion, increased load on the forelimb (carpus) produced carpal hyperextension with measurable radiographic changes in the position and alignment of the carpal bones. The non-stretching (strain) or shortening of the Cr-Ci ICL during loading, indicated by the decrease in GW.Cr-Ci ICL, suggests a relaxed intercarpal ligament within a confined space which appears to absorb compressional load transferred from carpal bones and redistribution of concussion forces within the carpal joint during loading thereby providing a useful mechanism to minimise carpal damage.
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Pathak, R. K., R. K. Merkle, R. D. Cummings, J. L. Goldstein, M. S. Brown i R. G. Anderson. "Immunocytochemical localization of mutant low density lipoprotein receptors that fail to reach the Golgi complex." Journal of Cell Biology 106, nr 6 (1.06.1988): 1831–41. http://dx.doi.org/10.1083/jcb.106.6.1831.
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In the low density lipoprotein (LDL) receptor system, blocks in intracellular movement of a cell surface receptor result from naturally occurring mutations. These mutations occur in patients with familial hypercholesterolemia. One class of mutant LDL receptor genes (class 2 mutations) produces a receptor that is synthesized and glycosylated in the endoplasmic reticulum (ER) but does not reach the cell surface. These receptors contain serine/threonine-linked (O-linked) carbohydrate chains with core N-acetylgalactosamine residues and asparagine-linked (N-linked) carbohydrate chains of the high mannose type that are only partially trimmed. To determine the site of blockage in transport, we used electron microscope immunohistochemistry to compare the intracellular location of LDL receptors in normal human fibroblasts with their location in class 2 mutant fibroblasts. In normal cells, LDL receptors were located in coated pits, coated vesicles, endosomes, multivesicular bodies, and portions of the Golgi complex. In contrast, the mutant receptors in class 2 cells were almost entirely confined to rough ER and irregular extensions of the rough ER. Metabolic labeling studies with [3H]glucosamine confirmed that these mutant receptors contain core O-linked sugars, suggesting that the enzymes that attach these residues are located in the rough ER or the transitional zone of the ER. These studies establish that naturally occurring mutations in cell surface receptors can cause the receptors to remain trapped in the ER, thereby preventing their normal function and producing a genetic disease.
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BRANDT, ANGELIKA. "Evolution of Antarctic biodiversity in the context of the past: the importance of the Southern Ocean deep sea". Antarctic Science 17, nr 4 (18.11.2005): 509–21. http://dx.doi.org/10.1017/s0954102005002932.
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Present day Southern Ocean benthic biodiversity is the result of climatic changes based on the break-up of Gondwana in the Cretaceous and the Cenozoic and the physiological potential of the fauna to cope with the climatic deterioration. Though many taxa survived the thermal drop in ocean bottom temperatures, zoogeographic ranges changed and some faunal elements even became extinct, e.g. benthic decapods and teleost fish, opening up new ecological niches and the potential for enormous adaptive radiations within some taxa, like the amphipods and isopods (peracarid crustaceans) and notothenioid fish. Ice-sheet extensions and retreats might have enhanced speciation processes as well as eurybathy. Biodiversity on the Antarctic shelf is high within the polychaetes, molluscs, and echinoderms, and within the amphipods and isopods possibly due to the Cenozoic extinction of the benthic decapods. Moreover, some shelf areas are characterized by accumulations of large suspension feeders like poriferans, bryozoans, ascidians, gorgonians, and hydroids. Palaeoclimatic changes also caused that many taxa of the modern, present day Southern Ocean benthic organisms are characterized by gigantism, slow metabolism, longevity, and a reduced number of offspring combined with late maturation. However, our biological knowledge is mainly confined to Southern Ocean shelf organism; we do not know much about the composition, biodiversity and zoogeography of the Southern Ocean deep sea animals. On this background the deep sea expeditions ANDEEP were born and the background and first results of these are presented herein.
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Begum, Momotaj, Sabina Yiasmeen, Sadia Noor Arabi, Abu Bakar Siddique i Md Noman Chowdhury. "Diagnostic Performance of Computed Tomography in Laryngeal Carcinoma and its Extension". Journal of Monno Medical College 9, nr 2 (12.10.2024): 63–67. http://dx.doi.org/10.3329/jmomc.v9i2.76085.
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Background: Laryngeal carcinoma is a common malignant neoplasm of the head and neck with high incidence of new malignancies worldwide every year. Several imaging techniques including magnetic resonance imaging (MRI) and computed tomography (CT) scans are widely used to detect laryngeal carcinoma. Of them, CT scan is relatively cheaper, easily available and sensitive in the evaluation of laryngeal carcinoma. Objective: To find out the diagnostic performance of CT scan in laryngeal carcinoma and its extensions. Methodology: This cross-sectional study was carried out in the department of Radiology and Imaging, Dhaka Medical CollegeHospital, Dhaka, during the period of July, 2016 to June, 2018 for a period of 2(two) years. A total of 50 samples were included purposively. The enrolled patients were attending outpatient department (OPD) or admitted in indoor and referred to the Radiology and Imaging department for CT scan. All the enrolled cases had laryngectomy and resected tissues were sent for histopathological examination. Data collection was done by the principal investigator and a preformed questionnaire was used during data collection. Following completion of data collection, it was analyzed by SPSS 20.0. Results: Age range of the patients was from 18 to 84 years, with the mean age of 61.2 years + 13.4 years standard deviation and a male-female ratio of about 7.3:1. By multidetector CT scan, majority (32, 64.00%) of the tumours were found confined in a specific area with no extension, followed by 12 (24.00%) involving both supraglottic and glottic region. On the other hand, by histopathology, almost all (47, 94.00%) of the cases were found malignant and majority of the malignant cases (31, 65.96%) were found without nodal metastasis. Validity tests of CT in the diagnosis of laryngeal carcinoma revealed sensitivity, specificity, accuracy and positive predictive values of 97.9%, 66.7%, 96% and 97.9% respectively. In case of nodal metastases, the sensitivity, specificity, accuracy and positive predictive value were 93.8%, 97%, 96% and 93.8% respectively. Conclusion: Contrast enhanced CT scan has good role in detecting nodal metastases, but had complementary role in detecting laryngeal carcinoma. Journal of Monno Medical College December, 2023; 9 (2): 63-67
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Paggi, A., G. Fabbiano, E. Nardini, M. Karovska, M. Elvis i J. Wang. "Dissecting the Extended X-Ray Emission in the Merging Pair NGC 6240: Photoionization and Winds". Astrophysical Journal 927, nr 2 (1.03.2022): 166. http://dx.doi.org/10.3847/1538-4357/ac5025.
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Abstract We present a detailed spectral and imaging analysis of the central 15″ radius (∼7.5 kpc) region of the merger galaxy NGC 6240 that makes use of all the available Chandra-ACIS data (0.3–3 keV effective exposure of ∼190 ks). This region shows extended X-ray structures with lower-energy counterparts imaged in CO, [O iii], and Hα line emission. We find both photoionized phases of possible nuclear excitation and thermal shock-excited emission in the different large-scale components: the northwest “loop” detected in Hα, the region surrounding the two nuclei, the large outflow region to the northeast detected in [O iii], and the southern X-ray extensions. The latter could be the ionization cone of the northern nucleus, with the N counterpart being obscured by the galaxy disk. The radial distribution of the X-ray surface brightness suggests a confined hot interstellar medium at r < 2.5 kpc, with a free-flowing wind at larger radii; if the confinement is magnetic, we estimate B-field values of ∼100 μG, similar to those measured in the halo of M82. The thermal gas of the extended halo at kT ∼ 1 keV absorbs soft X-rays from the active galactic nucleus, but not the extreme ultraviolet radiation leading to a rapid increase in F [O III]/F X beyond ∼3 kpc. The α-element to Fe abundance ratios of the thermal components in the different regions of the extended X-ray emission are generally compatible with Type II supernova yields, confirming the importance of active star formation in NGC 6240.
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Byrne, Michael P., i Paul A. O’Gorman. "Land–Ocean Warming Contrast over a Wide Range of Climates: Convective Quasi-Equilibrium Theory and Idealized Simulations". Journal of Climate 26, nr 12 (15.06.2013): 4000–4016. http://dx.doi.org/10.1175/jcli-d-12-00262.1.
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Abstract Surface temperatures increase at a greater rate over land than ocean in simulations and observations of global warming. It has previously been proposed that this land–ocean warming contrast is related to different changes in lapse rates over land and ocean because of limited moisture availability over land. A simple theory of the land–ocean warming contrast is developed here in which lapse rates are determined by an assumption of convective quasi-equilibrium. The theory predicts that the difference between land and ocean temperatures increases monotonically as the climate warms or as the land becomes more arid. However, the ratio of differential warming over land and ocean varies nonmonotonically with temperature for constant relative humidities and reaches a maximum at roughly 290 K. The theory is applied to simulations with an idealized general circulation model in which the continental configuration and climate are varied systematically. The simulated warming contrast is confined to latitudes below 50° when climate is varied by changes in longwave optical thickness. The warming contrast depends on land aridity and is larger for zonal land bands than for continents with finite zonal extent. A land–ocean temperature contrast may be induced at higher latitudes by enforcing an arid land surface, but its magnitude is relatively small. The warming contrast is generally well described by the theory, although inclusion of a land–ocean albedo contrast causes the theory to overestimate the land temperatures. Extensions of the theory are discussed to include the effect of large-scale eddies on the extratropical thermal stratification and to account for warming contrasts in both surface air and surface skin temperatures.
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Cao, Jing, Zuowei Wang i Alexei Likhtman. "Determining Tube Theory Parameters by Slip-Spring Model Simulations of Entangled Star Polymers in Fixed Networks". Polymers 11, nr 3 (14.03.2019): 496. http://dx.doi.org/10.3390/polym11030496.
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Dynamical properties of branched polymer melts are determined by the polymer molecular weights and architectures containing junction points. Relaxation of entangled symmetric star polymers proceeds via arm-retraction and constraint release (CR). In this work, we investigate arm-retraction dynamics in the framework of a single-chain slip-spring model without CR effect where entanglements are treated as binary contacts, conveniently modeled as virtual “slip-links”, each involving two neighboring strands. The model systems are analogous to isolated star polymers confined in a permanent network or a melt of very long linear polymers. We find that the distributions of the effective primitive path lengths are Gaussian, from which the entanglement molecular weight N e , a key tube theory parameter, can be extracted. The procured N e value is in good agreement with that obtained from mapping the middle monomer mean-square displacements of entangled linear chains in slip-spring model to the tube model prediction. Furthermore, the mean first-passage (FP) times of destruction of original tube segments by the retracting arm end are collected in simulations and examined quantitatively using a theory recently developed in our group for describing FP problems of one-dimensional Rouse chains with improbable extensions. The asymptotic values of N e as obtained from the static (primitive path length) and dynamical (FP time) analysis are consistent with each other. Additionally, we manage to determine the tube survival function of star arms μ ( t ) , or equivalently arm end-to-end vector relaxation function ϕ ( t ) , through the mean FP time spectrum τ ( s ) of the tube segments after careful consideration of the inner-most entanglements, which shows reasonably good agreement with experimental data on dielectric relaxation.
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POULI, Aristea E., Evaggelia EMMANOUILIDOU, Chao ZHAO, Christina WASMEIER, John C. HUTTON i Guy A. RUTTER. "Secretory-granule dynamics visualized in vivo with a phogrin–green fluorescent protein chimaera". Biochemical Journal 333, nr 1 (1.07.1998): 193–99. http://dx.doi.org/10.1042/bj3330193.
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To image the behaviour in real time of single secretory granules in neuroendocrine cells we have expressed cDNA encoding a fusion construct between the dense-core secretory-granule-membrane glycoprotein, phogrin (phosphatase on the granule of insulinoma cells), and enhanced green fluorescent protein (EGFP). Expressed in INS-1 β-cells and pheochromocytoma PC12 cells, the chimaera was localized efficiently (up to 95%) to dense-core secretory granules (diameter 200–1000 nm), identified by co-immunolocalization with anti-(pro-)insulin antibodies in INS-1 cells and dopamine β-hydroxylase in PC12 cells. Using laser-scanning confocal microscopy and digital image analysis, we have used this chimaera to monitor the effects of secretagogues on the dynamics of secretory granules in single living cells. In unstimulated INS-1 β-cells, granule movement was confined to oscillatory movement (dithering) with period of oscillation 5–10 s and mean displacement < 1 µm. Both elevated glucose concentrations (30 mM), and depolarization of the plasma membrane with K+, provoked large (5–10 µm) saltatory excursions of granules across the cell, which were never observed in cells maintained at low glucose concentration. By contrast, long excursions of granules occurred in PC12 cells without stimulation, and occurred predominantly from the cell body towards the cell periphery and neurite extensions. Purinergic-receptor activation with ATP provoked granule movement towards the membrane of PC12 cells, resulting in the transfer of fluorescence to the plasma membrane consistent with fusion of the granule and diffusion of the chimaera in the plasma membrane. These results illustrate the potential use of phogrin–EGFP chimeras in the study of secretory-granule dynamics, the regulation of granule–cytoskeletal interactions and the trafficking of a granule-specific transmembrane protein during the cycle of exocytosis and endocytosis.
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Koch, R. L., E. F. Rybicki i R. D. Strattan. "A Computational Temperature Analysis for Induction Heating of Welded Pipes". Journal of Engineering Materials and Technology 107, nr 2 (1.04.1985): 148–53. http://dx.doi.org/10.1115/1.3225791.
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Recent approaches to controlling stress corrosion cracking in welded 304 stainless steel pipes have been based on various types of controlled heating procedures. When applied properly, the heating procedure introduces high compressive stresses in region of observed cracking. The compressive stresses are believed to be effective in deterring stress corrosion cracking. One procedure for applying controlled heating to the pipe employs induction heating and is called Induction Heating for Stress Improvement or IHSI. The effective utilization of induction heating requires an understanding of how the induction heating parameters are related to the resulting residual stresses. This paper describes the development of a computational model directed at evaluating the heat densities and temperature distributions for Induction Heating for Stress Improvement (IHSI). The basic mechanism of inducting differs from that of a welding arc in that induction heating produces a distribution of heat sources within the pipe wall while in weld arc heating, the heat source is confined to the surface. Thus the computational model requires two parts. The first part evaluates the induced electrical current and determines the density of heat sources in the pipe wall. The second part of the model uses these heating densities to evaluate the temperature distribution. Temperature dependent properties were found to be important in representing the induction heating phenomenon. However, including temperature dependent properties in the model leads to nonlinear equations which require iterative solution methods for each part of the model. The nonlinear characteristics of the equations also require iterations between the two parts of the model. The model includes the important parameters of the induction heating process and has shown good agreement with temperature data for two different pipe sizes. Because of the inherent nonlinearities in the model and the iterative methods required for general solutions, extensions of the model to improve the algorithimic efficiency are discussed.
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Lee, Doojin, i Amy Q. Shen. "Interfacial Tension Measurements in Microfluidic Quasi-Static Extensional Flows". Micromachines 12, nr 3 (6.03.2021): 272. http://dx.doi.org/10.3390/mi12030272.
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Droplet microfluidics provides a versatile tool for measuring interfacial tensions between two immiscible fluids owing to its abilities of fast response, enhanced throughput, portability and easy manipulations of fluid compositions, comparing to conventional techniques. Purely homogeneous extension in the microfluidic device is desirable to measure the interfacial tension because the flow field enables symmetric droplet deformation along the outflow direction. To do so, we designed a microfluidic device consisting of a droplet production region to first generate emulsion droplets at a flow-focusing area. The droplets are then trapped at a stagnation point in the cross junction area, subsequently being stretched along the outflow direction under the extensional flow. These droplets in the device are either confined or unconfined in the channel walls depending on the channel height, which yields different droplet deformations. To calculate the interfacial tension for confined and unconfined droplet cases, quasi-static 2D Darcy approximation model and quasi-static 3D small deformation model are used. For the confined droplet case under the extensional flow, an effective viscosity of the two immiscible fluids, accounting for the viscosity ratio of continuous and dispersed phases, captures the droplet deformation well. However, the 2D model is limited to the case where the droplet is confined in the channel walls and deforms two-dimensionally. For the unconfined droplet case, the 3D model provides more robust estimates than the 2D model. We demonstrate that both 2D and 3D models provide good interfacial tension measurements under quasi-static extensional flows in comparison with the conventional pendant drop method.
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Choudhury, Masudul Alam. "Res extensa et res cogitans de maqasid as-shari’ah". International Journal of Law and Management 57, nr 6 (9.11.2015): 662–93. http://dx.doi.org/10.1108/ijlma-07-2014-0046.
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Purpose – This paper aims to undertake a critical evaluation of the purpose and objective of Islamic Law, namely, maqasid as-shari’ah, as it has evolved in Islamic scholastic experience. But, the greater philosophy and potential of maqasid as-shari’ah within the great design of the monotheistic law, sunnat-Allah, is explained. Such explanation is carried out in the light of the core of Islamic epistemology that directly induces Islamic Law. Design/methodology/approach – This critical evaluation is pursued in the light of the epistemological worldview and its methodical formalism of unity of knowledge contra a differentiated and conflicting view of human experience in rationalism. The episteme of unity of knowledge is Tawhid as the law of everything in the precept of unity as understood by the monotheistic law, sunnat-Allah. In the light of the extendibility of maqasid as-shari’ah across the relationally unifying domain of sunnat-Allah, the potentiality of shari’ah in terms of res extensa (epistemic extension) and res cogitans (cognitive capacity) is discussed. Findings – Various occidental thoughts in this quest for extendibility of the epistemic totality are critically examined by the Tawhidi monotheistic law. The universality of the Tawhidi law of monotheism in respect of its characteristics of res extensa and res cogitans is studied to bring out the potentiality of maqasid as-shari’ah. Thereby, the new vision of inter-systemic extensions across diverse domains of intellection interactively unified together is formalized. This formalism goes beyond the existing limits of maqasid as-shari’ah confined as it is to worldly socioeconomic affairs (muamalat). Research limitations/implications – A much broader investigation is opened up by this paper that can be extended by academic work. Practical implications – The practical support of the criticism against both the idea of shari’ah-compliance and the incomplete implication of maqasid as-shari’ah as presently understood among Islamic scholars is carried out by a detailed empirical work. The extension to the choice of a new financial instrument of Foreign Trade Financing Certificate is introduced. Social implications – The critical discussion launched in reference to the wider meaning, objective and purpose of maqasid as-shari’ah under the epistemology of the Tawhidi methodological worldview results in the substantive understanding of maslaha, well-being. Maslaha as well-being forms the ultimate index of socio-scientific valuation under maqasid as-shari’ah in the light of the Tawhidi epistemological worldview. Thereby, the perspective of socioeconomic development, and more extensively socio-scientific intellection, is brought out as extensively participatory evolutionary process under the principle of unity of knowledge (Tawhidi episteme). Brief examples are invoked to establish this fact. An example of measured multidimensional well-being (maslaha) as the final index of participatory organic relations that maqasid as-shari’ah ought to project in reference to Tawhidi methodological worldview is represented. Originality/value – This is a distinctively original paper in an area that has not been investigated thus far. Besides, much scope for further intellectual investigation is opened up.
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Cifra, Peter, Zuzana Benková i Tomáš Bleha. "Chain Extension of DNA Confined in Channels". Journal of Physical Chemistry B 113, nr 7 (19.02.2009): 1843–51. http://dx.doi.org/10.1021/jp806126r.
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Pegler, Samuel S. "The dynamics of confined extensional flows". Journal of Fluid Mechanics 804 (31.08.2016): 24–57. http://dx.doi.org/10.1017/jfm.2016.516.
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I present a theoretical and experimental study of floating viscous fluid films introduced into a channel of finite length, motivated by the flow of glacial ice shelves. The dynamics are characterized by a mixture of viscous extensional stresses, transverse shear stresses and a driving buoyancy force. A theory based on a width-integrated model is developed and investigated using analytical, asymptotic and numerical methods. With fluid introduced at a constant rate, the flow is found to approach a steady state with two possible asymptotic forms depending on the length of the channel. For channel lengths less than half the width, the flow is similar to a purely extensional one-dimensional flow, characterized by concave surface profiles and being insensitive to the position of the channel exit (or calving front). Greater lengths result in a more complex asymptotic structure in which the flow adjusts over a short distance towards a prevailing flow of universal dimensionless form. In complete contrast to the extensional regime, the prevailing flow is controlled by the position of the channel exit. Data from a new laboratory experiment involving particle velocimetry of a floating fluid film compares well with the predicted along-channel velocity. Motivated by glaciological application, the analysis is generalized to power-law rheologies and the results used to classify the flow regimes of a selection of ice shelves. The prediction for the frontal speed is in good agreement with geophysical data, indicating that the universal profile predicted by the theory is common in nature.
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Din, Allan M. "Quantum mechanical reality according to Copenhagen 2.0". International Journal of Modern Physics A 31, nr 14n15 (26.05.2016): 1630014. http://dx.doi.org/10.1142/s0217751x16300143.
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The long-standing conceptual controversies concerning the interpretation of nonrelativistic quantum mechanics are argued, on one hand, to be due to its incompleteness, as affirmed by Einstein. But on the other hand, it appears to be possible to complete it at least partially, as Bohr might have appreciated it, in the framework of its standard mathematical formalism with observables as appropriately defined self-adjoint operators. This completion of quantum mechanics is based on the requirement on laboratory physics to be effectively confined to a bounded space region and on the application of the von Neumann deficiency theorem to properly define a set of self-adjoint extensions of standard observables, e.g. the momenta and the Hamiltonian, in terms of certain isometries on the region boundary. This is formalized mathematically in the setting of a boundary ontology for the so-called Qbox in which the wave function acquires a supplementary dependence on a set of Additional Boundary Variables (ABV). It is argued that a certain geometric subset of the ABV parametrizing Quasi-Periodic Translational Isometries (QPTI) has a particular physical importance by allowing for the definition of an ontic wave function, which has the property of epitomizing the spatial wave function “collapse.” Concomitantly the standard wave function in an unbounded geometry is interpreted as an epistemic wave function, which together with the ontic QPTI wave function gives rise to the notion of two-wave duality, replacing the standard concept of wave-particle duality. More generally, this approach to quantum physics in a bounded geometry provides a novel analytical basis for a better understanding of several conceptual notions of quantum mechanics, including reality, nonlocality, entanglement and Heisenberg’s uncertainty relation. The scope of this analysis may be seen as a foundational update of the multiple versions 1.x of the Copenhagen interpretation of quantum mechanics, which is sufficiently incremental so as to be appropriately characterized as Copenhagen 2.0.
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Carbutt, Clinton. "The Greater Midlands—A Mid-Elevation Centre of Floristic Endemism in Summer-Rainfall Eastern South Africa". Diversity 15, nr 11 (9.11.2023): 1137. http://dx.doi.org/10.3390/d15111137.
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The Midlands region of KwaZulu-Natal (KZN) Province in South Africa was hitherto a putative centre of floristic endemism (CFE) based on conjecture. The aim of this study was to empirically explore this concept by delineating unambiguous boundaries for this CFE and documenting the endemic spermatophytes within a conservation framework. The Greater Midlands Centre of Floristic Endemism (GMCFE), a more expanded study area than the parochial Midlands region of KZN, is formally described as southern Africa’s 20th CFE. It is a mid-elevation region occupying the greater Midlands of KZN, with extensions of contiguous grasslands extending northwards into southern Mpumalanga and southwards into north-eastern Eastern Cape. This “foothills” CFE covers ca. 77,000 km2 of predominantly mesic C4 grassland, ranging in elevation from ca. 700–2200 m a.s.l. It is congruent with the “sub-escarpment ecoregion,” essentially a composite of the Sub-escarpment Grassland and Savanna Bioregions and the sub-escarpment grasslands of southern Mpumalanga and northern KZN. The GMCFE hosts at least 220 endemic spermatophytes, of which almost a fifth belong to the family Apocynaceae. Families Asteraceae, Asphodelaceae, Fabaceae, and Iridaceae also contribute significantly. Genera Ceropegia, Aloe, Dierama, Kniphofia, Helichrysum, and Streptocarpus contribute the most endemics. More than half are forbs, and almost three-quarters are confined to the Grassland Biome. Endemic radiations are attributed to geodiversity and geological complexity (especially the strong lithological influence of dolerite); physiographic heterogeneity (particularly elevation gradients and variable terrain units); strategic proximity to hyper-diverse temperate and subtropical “border floras”; and localized pollinator-driven adaptive radiations. Of alarming concern is the high number of threatened plant taxa, with ca. 60% of the endemic flora Red Listed in threat categories (CE, E, and VU) or considered “rare”. Extremely low levels of formal protection and poor ecological connectivity, coupled with high levels of land transformation and intensive utilization, render the GMCFE one of the most imperilled CFE in South Africa. Urgent conservation action is required to safeguard this unique and highly threatened “rangeland flora” and stem the biodiversity crisis gripping the region.
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Watters, Thomas R., Francis Nimmo i Mark S. Robinson. "Extensional troughs in the Caloris Basin of Mercury: Evidence of lateral crustal flow". Geology 33, nr 8 (1.08.2005): 669–72. http://dx.doi.org/10.1130/g21678ar.1.
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Abstract Thirty years ago Mariner 10 revealed extensional troughs that form giant polygons in the floor material of the Caloris impact basin, Mercury. The polygonal troughs occur in the interior of the basin and overprint wrinkle ridges formed in an earlier stage of compression. In contrast, lunar and martian basins exhibit extensional troughs that are circumferential and confined to basin margins. Loading by basin-filling material can explain the extensional and compressional features seen in deformed lunar and martian basins, but not the existence of the Caloris polygonal troughs. Here we suggest that the Caloris troughs formed from late-stage basin uplift and extension due to lateral flow of a relatively thick crust toward the basin center. If such lateral flow occurs, the resulting timing, location, and magnitude of the extensional stresses predicted by our model are consistent with those inferred from the polygonal troughs. These results are not strongly dependent on the degree of lateral flow or the assumed crustal rigidity. For a dry plagioclase rheology and likely radiogenic heat fluxes, the crustal thickness around Caloris is 90–140 km. Similar late-stage uplift and extension probably do not occur in basins on the Moon and Mars because their crusts are too thin to allow analogous lateral flow.
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Moshel, Yaron A., Erik C. Parker i Patrick J. Kelly. "OCCIPITAL TRANSTENTORIAL APPROACH TO THE PRECENTRAL CEREBELLAR FISSURE AND POSTERIOR INCISURAL SPACE". Neurosurgery 65, nr 3 (1.09.2009): 554–64. http://dx.doi.org/10.1227/01.neu.0000350898.68212.ab.
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Abstract OBJECTIVE To describe the surgical techniques and postoperative clinical outcomes with the occipital transtentorial (OT) approach in patients harboring lesions arising from the precentral cerebellar fissure, posterior incisural space, and adjoining structures. METHODS Twenty-two patients underwent microsurgical resection of intra-axial lesions arising within the precentral cerebellar fissure and posterior incisural space between 1997 and 2006. Patient demographics, presenting symptoms, pathology, and neurological outcomes were retrospectively reviewed. Pre- and postoperative magnetic resonance imaging scans were evaluated to determine the anatomic extensions of the lesion and the degree of surgical resection. Patients with lesions primarily confined to the pineal and posterior third ventricle approached by a supracerebellar infratentorial trajectory were excluded from this study. RESULTS Of the 22 patients reported in this series, 17 (77%) had contrast-enhancing lesions, and 5 (23%) had nonenhancing lesions arising from the precentral cerebellar fissure and posterior incisural space. The lesions were oriented dorsomedial to the midbrain and diencephalon in 6 patients (27%), dorsolateral in 14 patients (64%), and lateral in 2 patients (9%). A lateral OT approach directed under the occipitotemporal junction was used in 16 patients (73%), and an interhemispheric OT approach was used in 6 patients (27%). Transient visual field loss occurred in 3 patients (14%); it resolved by the third follow-up month. Gross total resection or near-total resection of the imaging-defined lesion volume was achieved in 19 patients (86%). CONCLUSION The OT approaches provide excellent exposure for lesions of the precentral cerebellar fissure, posterior incisural space, and adjacent structures. The lateral OT approach directed under the occipitotemporal junction provides an inline view for lesions situated posterolateral to the brainstem. It also provides an inferiorly directed view under the venous system into the precentral cerebellar fissure and fourth ventricular roof. Visual field deficits are minimized by directing the trajectory under the occipitotemporal junction instead of retracting along the interhemispheric corridor. The interhemispheric OT approach was primarily used for lesions extending superiorly, in the midline or near midline, above the tentorium and venous system into the splenium of corpus callosum, lateral ventricle, and posterior thalamus, where extensive lateral retraction was not required.
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Nielsen, S., J. Muller i M. A. Knepper. "Vasopressin- and cAMP-induced changes in ultrastructure of isolated perfused inner medullary collecting ducts". American Journal of Physiology-Renal Physiology 265, nr 2 (1.08.1993): F225—F238. http://dx.doi.org/10.1152/ajprenal.1993.265.2.f225.
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Studies were performed to correlate arginine vasopressin (AVP)-induced changes in epithelial ultrastructure with changes in osmotic water permeability in isolated perfused rat terminal inner medullary collecting ducts (tIMCD). The tubules were perfused in three time periods, i.e., a 40-min basal period, a 40-min period with 0.1 nM AVP in the bath, and a 60-min withdrawal period. In each phase, the osmotic water permeability (Pf) was measured, and the perfused tubules were fixed for electron microscopy. AVP caused a four- to eightfold increase in Pf and induced several ultrastructural changes as follows: increased cell height of IMCD cells, expansion of the intercellular spaces, formation of large vacuoles, and increased coated pit density in the apical plasma membrane [from 0.6 +/- 0.2 (n = 6) to 2.9 +/- 0.3 (n = 7) pits/100 microns membrane length]. During AVP withdrawal, Pf decreased toward the basal value in association with partial reversal of the ultrastructural changes including a decrease in coated pit density to 1.0 +/- 0.2 (n = 4). Stimulation with 8-bromoadenosine 3',5'-cyclic monophosphate (8-bromo-cAMP) (0.1 mM) produced similar changes in Pf. Coated pit density increased to 2.1 +/- 0.4 (n = 4) after cAMP stimulation and after cAMP withdrawal decreased to 1.2 +/- 0.2 (n = 6). In contrast to stimulation with AVP, cAMP stimulation did not result in dilated intercellular spaces or formation of large vacuoles. The only ultrastructural feature that directly correlated with the water permeability was the density of coated pits in the apical membrane. Organelles involved in the endocytic pathway were studied with cationized ferritin or albumin-gold in the luminal perfusate. At the end of 40 min basal perfusion or AVP stimulation, luminal tracer was found almost exclusively in large multivesicular bodies (MVB). Tubules perfused with tracer during AVP withdrawal demonstrated rapid tracer accumulation in small vesicles and small MVB within 3-5 min, a time point corresponding to the rapid phase of Pf decrease. Later (30-60 min) the label was mainly confined to large MVB. Occasionally during AVP stimulation or withdrawal, small coated vesicles and smooth vesicles with coated extensions were noted to contain tracer. The data demonstrate AVP-mediated coated pit formation and cellular changes and show very rapid internalization of apical membrane after AVP withdrawal.
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G .P. Mietus, W., O. K. Matar, C. J. Lawrence i B. J. Briscoe. "Droplet deformation in confined shear and extensional flow". Chemical Engineering Science 57, nr 7 (kwiecień 2002): 1217–30. http://dx.doi.org/10.1016/s0009-2509(02)00018-0.
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Benková, Zuzana, i Peter Cifra. "Comparison of linear and ring DNA macromolecules moderately and strongly confined in nanochannels". Biochemical Society Transactions 41, nr 2 (21.03.2013): 625–29. http://dx.doi.org/10.1042/bst20120279.
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Understanding the mechanism of DNA extension in nanochannels is necessary for interpretation of experiments in nanofluidic channel devices that have been conducted recently with both linear and ring chains. The present article reviews the situation with linear chains and analyses the experimental results and simulations for channel-induced extension (linearization) of ring chains. Results for confined rings indicate a transition between moderate and strong confinement similar to that of linear chains. Owing to stronger self-avoidance in confined rings, the transition and chain extension is shifted relative to linear DNA. We suggest that a relationship similar to that used for the extension of linear chains may also be used for circular DNA.
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Wilson, Elizabeth Parker, Pablo Granado, Pablo Santolaria, Oriol Ferrer i Josep Anton Muñoz. "Inversion of accommodation zones in salt-bearing extensional systems: insights from analog modeling". Solid Earth 14, nr 7 (12.07.2023): 709–39. http://dx.doi.org/10.5194/se-14-709-2023.
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Abstract. This work uses sandbox analog models to analyze the formation and subsequent inversion of a decoupled extensional system comprised of two segmented half-grabens separated by a diffuse accommodation zone with thick early syn-rift salt. The segmented half-grabens strike perpendicular to the direction of extension and subsequent shortening. Rifting first created a basement topography that was infilled by model salt, followed by a second phase of extension and sedimentation, followed afterwards by inversion. During the second phase of extension, syn-rift syncline minibasins developed above the basement extensional system and extended beyond the confines of the fault blocks. Sedimentary downbuilding and extension initiated the migration of model salt to the basement highs, forming salt anticlines, reactive diapirs, and salt walls perpendicular to the direction of extension, except for along the intervening accommodation zone where a slightly oblique salt anticline developed. Inversion resulted in decoupled cover and basement thrust systems. Thrusts in the cover system nucleated along squeezed salt structures and along primary welds. New primary welds developed where the cover sequence touched down on basement thrust tips due to uplift, salt extrusion, and syn-contractional downbuilding caused by the loading of syn-contractional sedimentation. Model geometries reveal the control imposed by the basement configuration and distribution of salt in the development of a thrust front from the inversion of a salt-bearing extensional system. In 3D, the interaction of salt migrating from adjacent syn-rift basins can modify the expected salt structure geometry, which may in turn influence the location and style of thrust in the cover sequence upon inversion. Results are compared to the Northern Lusitanian Basin, offshore Portugal, and the Isábena area of the South-Central Pyrenees, Spain.
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MEZGER, JOCHEN E., i CEES W. PASSCHIER. "Polymetamorphism and ductile deformation of staurolite–cordierite schist of the Bossòst dome: indication for Variscan extension in the Axial Zone of the central Pyrenees". Geological Magazine 140, nr 5 (wrzesień 2003): 595–612. http://dx.doi.org/10.1017/s0016756803008112.
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The Bossòst dome is an E–W-trending elongated structural and metamorphic dome developed in Cambro-Ordovician metasedimentary rocks in the Variscan Axial Zone of the central Pyrenees. A steep fault separates a northern half-dome, cored by massif granite, from an E–W-trending doubly plunging antiform with granitic sills and dykes in the core to the south. The main foliation is a flat-lying S1/2 schistosity that grades into a steeper-dipping slaty cleavage at the dome margins. Three major deformational and two metamorphic phases can be differentiated. S1/2 schistosity is an axial planar cleavage to W-vergent recumbent folding that probably occurred in mid-Westphalian time. Peak regional metamorphism M1 is characterized by static growth of staurolite and garnet following thermal relaxation of the previously thickened crust. Strong non-coaxial deformation recording uniform top-to-the-SE extension during D2a is preserved in staurolite–garnet schists in a 1.5 km thick, shallowly SE-dipping zone in the southeastern dome. A 500 m thick contact aureole (M2) was imprinted on the regionally metamorphosed rocks following the intrusion the Bossòst granite during D2b. More coaxial deformation prevailed during synkinematic growth of M2 phases in the inner part of the contact aureole around the northern part of the dome, where it obliterated D2a fabrics. Progressive non-coaxial deformation continued in the southeastern antiform and is recorded by late-synkinematic growth of cordierite. Successive overprinting of the M1 staurolite–garnet assemblage by andalusite and cordierite of M2 is preserved in the southern part. The assemblage muscovite+cordierite+staurolite+biotite is considered metastable, given the low Mn and Zn contents of staurolite and cordierite, and interpreted as the result of prograde metamorphism during decompression. P–T conditions during M2 were approximately 3 kbar and 600 °C. Pervasive crenulations and mesoscopic to regional southerly verging folds are the result of D3 NNE–SSW compression post-dating ductile deformation and contact metamorphism. Polymetamorphic assemblages of the Bossòst dome preserve a regionally confined zone of ESE-directed extensional shearing within an overall N–S compressional setting. Exact timing of extensional shearing is not known, but can be constrained by recumbent folding during the mid-Westphalian and granitic intrusions, which confine it to Late Carboniferous time (c. 305 Ma). Crustal-scale flat-lying extensional shear zones with similar orientation and time frame are observed in the Hospitalêt massif of the eastern Axial Zone. This suggests that crustal extension, though probably restricted by regional strain partitioning over orthogneiss or intruding granitic bodies within an overall compressive setting, was not uncommon in Late Carboniferous time in the Axial Zone of the Pyrenees.
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Scholz, Christopher A., Donna J. Shillington, Lachlan J. M. Wright, Natalie Accardo, James B. Gaherty i Patrick Chindandali. "Intrarift fault fabric, segmentation, and basin evolution of the Lake Malawi (Nyasa) Rift, East Africa". Geosphere 16, nr 5 (10.07.2020): 1293–311. http://dx.doi.org/10.1130/ges02228.1.
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Abstract The Lake Malawi (Nyasa) Rift, in the East African Rift System (EARS), is an ideal modern analogue for the study of extensional tectonic systems in low strain rate settings. The seismically active rift contains the 700-m-deep Lake Malawi, one of the world’s oldest and largest freshwater lakes with one of the most diverse endemic faunal assemblages on Earth. Modern and reprocessed legacy multichannel seismic-reflection data are constrained by velocity information from a wide-angle seismic experiment to evaluate variability in extension, segmentation, and timing of fault development along the 550-km-long rift zone. Fault geometries and patterns of synrift sediment fills show that the Lake Malawi Rift is composed of three asymmetric rift segments, with intervening accommodation zone morphologies controlled by the degree of overlap between segment border faults. Most extension occurs on the basin border faults, and broadly distributed extension is only observed at one accommodation zone, where no border fault overlap is observed. Structural restorations indicate a weakly extended rift system (∼7 km), with diminishing values of extension and thinner rift fill from north to south, suggesting a progressively younger rift to the south. There is no evidence of diking, sill injection, or extrusives within the synrift fill of the Lake Malawi Rift, although the volcanic load of the Rungwe magmatic system north of the lake and related subsidence may explain the presence of anomalously thick synrift fill in the northernmost part of the lake. The thickest synrift depocenters (∼5.5 km) are confined to narrow 10- to 20-km-wide zones adjacent to each rift segment border fault, indicating concentration of strain on border faults rather than intrarift faults. Intrarift structures control axial sediment delivery in the North and Central rift segments, focusing sediment into confined areas resulting in localized overpressure and shale diapirs. The asymmetric, basement-controlled relief was established early in rift development. When overprinted with frequent high-amplitude hydroclimate fluctuations, which are well documented for this basin, the resulting highly variable landscape and lake morphometry through time likely impacted the diverse endemic faunas that evolved within the basin. New seismic-reflection data, augmented by wide-angle seismic data and age constraints from drill core, offer the most highly resolved 3D view to date of latest Cenozoic extensional deformation in East Africa and provide a foundation for hazards analysis, resource assessments, and constraining deformation in a low strain rate, magma-poor active rift.
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Contreras, Sergio, i Alejandro Gil-Villegas. "Confined Quantum Hard Spheres". Entropy 23, nr 6 (18.06.2021): 775. http://dx.doi.org/10.3390/e23060775.
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We present computer simulation and theoretical results for a system of N Quantum Hard Spheres (QHS) particles of diameter σ and mass m at temperature T, confined between parallel hard walls separated by a distance Hσ, within the range 1≤H≤∞. Semiclassical Monte Carlo computer simulations were performed adapted to a confined space, considering effects in terms of the density of particles ρ*=N/V, where V is the accessible volume, the inverse length H−1 and the de Broglie’s thermal wavelength λB=h/2πmkT, where k and h are the Boltzmann’s and Planck’s constants, respectively. For the case of extreme and maximum confinement, 0.5<H−1<1 and H−1=1, respectively, analytical results can be given based on an extension for quantum systems of the Helmholtz free energies for the corresponding classical systems.
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Cosoli, Simone, Charitha Pattiaratchi i Yasha Hetzel. "High-Frequency Radar Observations of Surface Circulation Features along the South-Western Australian Coast". Journal of Marine Science and Engineering 8, nr 2 (5.02.2020): 97. http://dx.doi.org/10.3390/jmse8020097.
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A new merged high-frequency radar (HFR) data set collected using SeaSonde and WERA (WEllen RAdar) systems was used to examine the ocean surface circulation at diurnal, seasonal and inter-annual time scales along the south-west coast of Australia (SWWA), between 29°–32° S. Merging was performed after resampling WERA data on the coarser SeaSonde HFR grid and averaging data from the two HFR systems in the area of common overlap. Direct comparisons between WERA and SeaSonde vectors in their overlapping areas provided scalar and vector correlation values in the range Ru = [0.24, 0.76]; Rv = [0.39, 0.83]; ρ = [0.44, 0.75], with mean bias between velocity components in the range [−0.02, 0.28] ms−1, [−0.16, 0.16] ms−1 for the U, V components, respectively. The lower agreement between vectors was obtained in general at the boundaries of the HFR domains, where the combined effects of the bearing errors, geometrical constraints, and the limited angular field of view were predominant. The combined data set allowed for a novel characterization of the dominant features in the region, such as the warmer poleward-flowing Leeuwin Current (LC), the colder Capes Current (CC) and its northward extensions, the presence of sub-mesoscale to mesoscale eddies and their generation and aggregation areas, along with the extent offshore of the inertial-diurnal signal. The contribution of tides was weak within the entire HFR domain (<10% total variance), whilst signatures of significant inertial- and diurnal-period currents were present due to diurnal–inertial resonance. A clear discontinuity in energy and variance distribution occurred at the shelf break, which separates the continental shelf and deeper offshore regions, and defined the core of the LC. Confined between the LC and the coastline, the narrower and colder CC current was a feature during the summer months. Persistent (lifespan greater than 1 day) sub-mesoscale eddies (Rossby number O (1)) were observed at two main regions, north and south of 31.5° S, offshore of the 200 m depth contour. The majority of these eddies had diameters in the range 10–20 km with 50% more counter clockwise rotating (CCW) eddies compared to clockwise (CW) rotating eddies. The northern region was dominated by CCW eddies that were present throughout the year whilst CW eddies were prevalent in the south with lower numbers during the summer months.
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Lloyd, F. E., A. D. Edgar, D. M. Forsyth i R. L. Barnett. "The paragenesis of upper-mantle xenoliths from the Quaternary volcanics south-east of Gees, West Eifel, Germany". Mineralogical Magazine 55, nr 378 (marzec 1991): 95–112. http://dx.doi.org/10.1180/minmag.1991.055.378.08.
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AbstractGroup I xenoliths, orthopyroxene-rich and orthopyroxene-free, contain Cr-spinel and clinopyroxene ± phlogopite, and occur together with Group II clinopyroxenites ± Ti-spinel ± phlogopite in K-mafic pyroclastics southeast of Gees. The petrography and clinopyroxene chemistry of orthopyroxene-rich (opx-rich sub-group) Group I xenoliths is consistent with an ‘original’ harzburgitic mantle that has been transformed to lherzolite by the addition of endiopside. In harzburgites, orthopyroxenes are reacting to diopside + olivine + alkali-silicate melt, and, by inference, the orthopyroxene-free (opx-free subgroup) Group I, dunite-wehrlite series can be linked to the opx-rich sub-group via this reaction. Progressive enrichment of dunitic material in endiopside-diopside has resulted in the formation of wehrlite. Phlogopite is titaniferous and occurs as a trace mineral in opx-rich, Group I xenoliths, whereas substantial phlogopite vein-networks are confined to the opx-free sub-group (dunite-wehrlite series). Interstitial, alkali-felsic glass occurs are veins within, and as extensions of, the phlogopite networks. Clinopyroxenes in phlogopite-veined xenoliths are decreased in Mg/(Mg + FeTotal) (mg) and Cr and increased in Ti, Al and Ca, compared with clinopyroxenes in xenoliths which have trace phlogopite. It is proposed that harzburgitic and dunitic mantle has been infiltrated by a Ca- and alkalirich, hydrous silicate melt rather than an ephemeral carbonatite melt. Dunite has been transformed to phlogopite wehrlite by the invasion of a Ca-, Al-, Ti- and K-rich, hydrous silicate melt. Ca-activity was high initially in the melt and was reduced by clinopyroxene precipitation. This resulted in enhanced K-activity which led to phlogopite veining of clinopyroxene-rich mantle. Group II phlogopite clinopyroxenites contain Ti-spinel and salites that are distinct in their Ti, Al and Cr contents from endiopsides and diopsides in Group I xenoliths. It is unlikely that these Group II xenoliths represent the culmination of the infiltration processes that have transformed dunite to wehrlite, nor can they be related to the host melt. These xenoliths may have crystallised from Ca- and K-bearing, hydrous silicate melts in mantle channelways buffered by previously precipitated clinopyroxene and phlogopite. Gees lherzolites contain pyroxenes and spinel with distinctly lower Al contents than these same minerals in lherzolites described previously from other West Eifel localities, which may reflect a distinctive lithology and/or processes of modification for the Gees mantle.
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Bhattacharyya, Pinaki, i Binny J. Cherayil. "Chain extension of a confined polymer in steady shear flow". Journal of Chemical Physics 137, nr 19 (21.11.2012): 194906. http://dx.doi.org/10.1063/1.4765295.
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Tian, Nan, Baijin Zhao, Xiangyang Li, Yanping Liu, Weiqing Zhou, Kunpeng Cui, Dong Liu i Liangbin Li. "Confined crystallization in end-linked PEO network under uniaxial extension". Polymer 54, nr 26 (grudzień 2013): 7088–93. http://dx.doi.org/10.1016/j.polymer.2013.10.055.
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Tu, Michael Q., Hung V. Nguyen, Elliel Foley, Michael I. Jacobs i Charles M. Schroeder. "3D manipulation and dynamics of soft materials in 3D flows". Journal of Rheology 67, nr 4 (15.06.2023): 877. http://dx.doi.org/10.1122/8.0000600.
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Flow-based manipulation of particles is an essential tool for studying soft materials, but prior work has nearly exclusively relied on using two-dimensional (2D) flows generated in planar microfluidic geometries. In this work, we demonstrate 3D trapping and manipulation of freely suspended particles, droplets, and giant unilamellar vesicles in 3D flow fields using automated flow control. Three-dimensional flow fields including uniaxial extension and biaxial extension are generated in 3D-printed fluidic devices combined with active feedback control for particle manipulation in 3D. Flow fields are characterized using particle tracking velocimetry complemented by finite-element simulations for all flow geometries. Single colloidal particles (3.4 μm diameter) are confined in low viscosity solvent (1.0 mPa s) near the stagnation points of uniaxial and biaxial extensional flow for long times (≥10 min) using active feedback control. Trap stiffness is experimentally determined by analyzing the power spectral density of particle position fluctuations. We further demonstrate precise manipulation of colloidal particles along user-defined trajectories in three dimensions using automated flow control. Newtonian liquid droplets and GUVs are trapped and deformed in precisely controlled uniaxial and biaxial extensional flows, which is a new demonstration for 3D flow fields. Overall, this work extends flow-based manipulation of particles and droplets to three dimensions, thereby enabling quantitative analysis of colloids and soft materials in complex nonequilibrium flows.