1000 resultados para band alignment


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Design of an Ultra Wide Band (UWB) filter over 3.1 GHz to 10.6 GHz using broad side coupled and spur lines in microstrip medium suitable for UWB communications has been presented in this paper. Parameters of broad side coupled lines have been appropriately chosen to achieve ultra wide band response. Spur lines have been incorporated at the input and output feed lines of the filter to improve the stop band rejection characteristics of the filter. Filter has been analyzed based on circuit models and full wave simulations. Experimental results of the filter designed using the proposed structure has been verified against the results obtained from circuit models and full wave simulations. The results match satisfactorily. Stop band rejection of better than 20 dB was obtained over the frequencies of 13 GHz to 18.2 GHz. Overall size of the filter is 40 x 18 x 0.787 mm(3).

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Despite compulsory mathematics throughout primary and junior secondary schooling, many schools across Australia continue in their struggle to achieve satisfactory numeracy levels. Numeracy is not a distinct subject in school curriculum, and in fact appears as a general capability in the Australian Curriculum, wherein all teachers across all curriculum areas are responsible for numeracy. This general capability approach confuses what numeracy should look like, especially when compared to the structure of numeracy as defined on standardised national tests. In seeking to define numeracy, schools tend to look at past NAPLAN papers, and in doing so, we do not find examples drawn from the various aspects of school curriculum. What we find are more traditional forms of mathematical worded problems.

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Placzek [1] was the first to derive general expressions for the intensities of overtones in case of Raman scattering. He assumed electrical anharmonicity. However, he left the expressions for the derivations of the polarizability tensor undetermined. In 1941, a classical and semiempirical theory was developed by Wolkenstein [2]. He assumed the validity of the additivity of bond polarizabilities. However, the expressions derived by him for the intensities of overtones remain yet to be verified. It is the purpose of this paper to derive a formula for Raman polarizability tensor for overtones of (intramolecular) vibrational spectra along the lines of Kondilenko et al. [3,4].

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A semiconductor with almost overlapping conduction bands b and c is considered. It is found that an attractive interaction leading to superconductivity can be induced between electrons in the conduction band b by a strong radiation field of monochromatic photons whose energy differs slightly from the band gap Ebc. The mechanism is the exchange of a photon and a phonon between the interacting electrons and the interaction is found to be proportional to the photon density.

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A simplified yet analytical approach on few ballistic properties of III-V quantum wire transistor has been presented by considering the band non-parabolicity of the electrons in accordance with Kane's energy band model using the Bohr-Sommerfeld's technique. The confinement of the electrons in the vertical and lateral directions are modeled by an infinite triangular and square well potentials respectively, giving rise to a two dimensional electron confinement. It has been shown that the quantum gate capacitance, the drain currents and the channel conductance in such systems are oscillatory functions of the applied gate and drain voltages at the strong inversion regime. The formation of subbands due to the electrical and structural quantization leads to the discreetness in the characteristics of such 1D ballistic transistors. A comparison has also been sought out between the self-consistent solution of the Poisson's-Schrodinger's equations using numerical techniques and analytical results using Bohr-Sommerfeld's method. The results as derived in this paper for all the energy band models gets simplified to the well known results under certain limiting conditions which forms the mathematical compatibility of our generalized theoretical formalism.

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Tension banding castration of cattle is gaining favour because it is relatively simple to perform and is promoted by retailers of the banders as a humane castration method. Two experiments were conducted, under tropical conditions using Bos indicus bulls comparing tension banding (Band) and surgical (Surgical) castration of weaner (7–10 months old) and mature (22–25 months old) bulls with and without pain management (NSAID (ketoprofen) or saline injected intramuscularly immediately prior to castration). Welfare outcomes were assessed using a range of measures; this paper reports on some physiological, morbidity and productivity-related responses to augment the behavioural responses reported in an accompanying paper. Blood samples were taken on the day of castration (day 0) at the time of restraint (0 min) and 30 min (weaners) or 40 min (mature bulls), 2 h, and 7 h; and days 1, 2, 3, 7, 14, 21 and 28 post-castration. Plasmas from day 0 were assayed for cortisol, creatine kinase, total protein and packed cell volume. Plasmas from the other samples were assayed for cortisol and haptoglobin (plus the 0 min sample). Liveweights were recorded approximately weekly to 6 weeks and at 2 and 3 months post-castration. Castration sites were checked at these same times to 2 months post-castration to score the extent of healing and presence of sepsis. Cortisol concentrations (mean ± s.e. nmol/L) were significantly (P < 0.05) higher in the Band (67 ± 4.5) compared with Surgical weaners (42 ± 4.5) at 2 h post-castration, but at 24 h post-castration were greater in the Surgical (43 ± 3.2) compared with the Band weaners (30 ± 3.2). The main effect of ketoprofen was on the cortisol concentrations of the mature Surgical bulls; concentrations were significantly reduced at 40 min (47 ± 7.2 vs. 71 ± 7.2 nmol/L for saline) and 2 h post-castration (24 ± 7.2, vs. 87 ± 7.2 nmol/L for saline). Ketoprofen, however, had no effect on the Band mature bulls, with their cortisol concentrations averaging 54 ± 5.1 nmol/L at 40 min and 92 ± 5.1 nmol/L at 2 h. Cortisol concentrations were also significantly elevated in the Band (83 ± 3.0 nmol/L) compared with Surgical mature bulls (57 ± 3.0 nmol/L) at weeks 2–4 post-castration. The timing of this elevation coincided with significantly elevated haptoglobin concentrations (mg/mL) in the Band bulls (2.97 ± 0.102 for mature bulls and 1.71 ± 0.025 for weaners, vs. 2.10 ± 0.102 and 1.45 ± 0.025 respectively for the Surgical treatment) and evidence of slow wound healing and sepsis in both the weaner (0.81 ± 0.089 not healed at week 4 for Band, 0.13 ± 0.078 for Surgical) and mature bulls (0.81 ± 0.090 at week 4 for Band, 0.38 ± 0.104 for Surgical). Overall, liveweight gains of both age groups were not affected by castration method. The findings of acute pain, chronic inflammation and possibly chronic pain in the mature bulls at least, together with poor wound healing in the Band bulls support behavioural findings reported in the accompanying paper and demonstrate that tension banding produces inferior welfare outcomes for weaner and mature bulls compared with surgical castration.

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Tension-band castration of cattle is gaining favour because it is relatively simple to perform and is promoted by retailers of the devices as a humane castration method. Furthermore, retailers encourage delaying castration to exploit the superior growth rates of bulls compared with steers. Two experiments were conducted, under tropical conditions, comparing tension banding and surgical castration of weaner (7–10 months old) and mature (22–25 months old) Bos indicus bulls with and without pain management (ketoprofen or saline injected intramuscularly immediately prior to castration). Welfare outcomes were assessed using a wide range of measures; this paper reports on the behavioural responses of the bulls and an accompanying paper reports on other measures. Behavioural data were collected at intervals by direct observation and continuously via data loggers on the hind leg of the bulls to 4 weeks post-castration. Tension-banded bulls performed less movement in the crush/chute than the surgically castrated bulls during the procedures (weaner: 2.63 vs. 5.69, P < 0.001; mature: 1.00 vs. 5.94; P < 0.001 for tension-band and surgical castration, respectively), indicating that tension banding was less painful then surgical castration during conduct. To 1.5 h post-castration, tension-banded bulls performed significantly (all P < 0.05) more active behavioural responses indicative of pain compared with surgical castrates, e.g., percentage time walking forwards (weaner: 15.0% vs. 8.1%; mature: 22.3% vs. 15.1%), walking backwards (weaner: 4.3% vs. 1.4%; mature: 2.4% vs. 0.5%), numbers of tail movements (weaner: 21.9 vs. 1.4; mature: 51.5 vs. 39.4) and leg movements (weaner: 12.9 vs. 0.9; mature: 8.5 vs. 1.5), respectively. In contrast, surgically castrated bulls performed more immobile behaviours compared with tension-banded bulls (e.g., standing in mature bulls was 56.6% vs. 34.4%, respectively, P = 0.002). Ketoprofen administration appeared effective in moderating pain-related behaviours in the mature bulls from 1.5 to 3 h, e.g., reducing abnormal standing (0.0% vs. 7.7%, P = 0.009) and increasing feeding (12.7% vs. 0.0%, P = 0.048) in NSAID- and saline-treated bulls, respectively. There were few behavioural differences subsequent to 24 h post-castration, but some limited evidence of chronic pain (3–4 weeks post-castration) with both methods. Interpretation, however, was difficult from behaviours alone. Thus, tension banding is less painful than surgical castration during conduct of the procedures and pain-related behavioural responses differ with castration method (active restlessness in response to tension banding and minimisation of movement in response to surgical castration). Ketoprofen administered immediately prior to castration was somewhat effective in reducing pain, particularly in the mature bulls.

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Several alkylidene malononitriles (1b,1d,1e,2b and4b) and alkylidene cyanoacetates (1a,2a and4a) studied exhibit a long wavelength UV absorption band around 355 nm which shows a hyperchromic effect in the presence of ethanolic alkali. This band has been assigned to the ketenimine tautomer (5). Addition of water to1b,1e and2b gives the corresponding pyridine diols (7a,7b and8a) respectively. Similarly, addition of ethanol to1e and2b gave the corresponding ethoxypyridine derivatives (7c and8b). Mechanism of formation of these compounds is discussed. Structures, as well as mechanism of formation of1c,7c and10 obtained from1b,1e and2b respectively on standing at room temperature are also discussed.

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Several alkylidene malononitriles (1b,1d,1e,2b and4b) and alkylidene cyanoacetates (1a,2a and4a) studied exhibit a long wavelength UV absorption band around 355 nm which shows a hyperchromic effect in the presence of ethanolic alkali. This band has been assigned to the ketenimine tautomer (5). Addition of water to1b,1e and2b gives the corresponding pyridine diols (7a,7b and8a) respectively. Similarly, addition of ethanol to1e and2b gave the corresponding ethoxypyridine derivatives (7c and8b). Mechanism of formation of these compounds is discussed. Structures, as well as mechanism of formation of1c,7c and10 obtained from1b,1e and2b respectively on standing at room temperature are also discussed.

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The needs of students engaged in enterprise education programs are of ever growing importance. This paper considers the pedagogical challenges that confront the designers of such-programs. It is argued that it is the designer's mindset that will most likely determine the program's outcomes. That, regardless of where such programs reside, their development should be guided by a learner-centred approach. The recently developed hic et nunc framework, provides an example of such a student-centred approach. The process through which student learning outcomes occur is argued to be essentially Darwinian in nature. Taking into account both knowledge and skills, it is also argued that assessment of desirable learning outcomes should occur in visible interaction spaces. That the failure to eliminate invisible interaction spaces from such programs is an invitation for criticism from those who favour a more traditional lecturer-centred approach to teaching and learning.

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This thesis which consists of an introduction and four peer-reviewed original publications studies the problems of haplotype inference (haplotyping) and local alignment significance. The problems studied here belong to the broad area of bioinformatics and computational biology. The presented solutions are computationally fast and accurate, which makes them practical in high-throughput sequence data analysis. Haplotype inference is a computational problem where the goal is to estimate haplotypes from a sample of genotypes as accurately as possible. This problem is important as the direct measurement of haplotypes is difficult, whereas the genotypes are easier to quantify. Haplotypes are the key-players when studying for example the genetic causes of diseases. In this thesis, three methods are presented for the haplotype inference problem referred to as HaploParser, HIT, and BACH. HaploParser is based on a combinatorial mosaic model and hierarchical parsing that together mimic recombinations and point-mutations in a biologically plausible way. In this mosaic model, the current population is assumed to be evolved from a small founder population. Thus, the haplotypes of the current population are recombinations of the (implicit) founder haplotypes with some point--mutations. HIT (Haplotype Inference Technique) uses a hidden Markov model for haplotypes and efficient algorithms are presented to learn this model from genotype data. The model structure of HIT is analogous to the mosaic model of HaploParser with founder haplotypes. Therefore, it can be seen as a probabilistic model of recombinations and point-mutations. BACH (Bayesian Context-based Haplotyping) utilizes a context tree weighting algorithm to efficiently sum over all variable-length Markov chains to evaluate the posterior probability of a haplotype configuration. Algorithms are presented that find haplotype configurations with high posterior probability. BACH is the most accurate method presented in this thesis and has comparable performance to the best available software for haplotype inference. Local alignment significance is a computational problem where one is interested in whether the local similarities in two sequences are due to the fact that the sequences are related or just by chance. Similarity of sequences is measured by their best local alignment score and from that, a p-value is computed. This p-value is the probability of picking two sequences from the null model that have as good or better best local alignment score. Local alignment significance is used routinely for example in homology searches. In this thesis, a general framework is sketched that allows one to compute a tight upper bound for the p-value of a local pairwise alignment score. Unlike the previous methods, the presented framework is not affeced by so-called edge-effects and can handle gaps (deletions and insertions) without troublesome sampling and curve fitting.

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We develop a two stage split vector quantization method with optimum bit allocation, for achieving minimum computational complexity. This also results in much lower memory requirement than the recently proposed switched split vector quantization method. To improve the rate-distortion performance further, a region specific normalization is introduced, which results in 1 bit/vector improvement over the typical two stage split vector quantizer, for wide-band LSF quantization.

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Relative band strengths of diatomic molecules for which the product of Franck-Condon factor and r-centroid is approximately equal to 1 for (0,0) band can be determined by a simple method which will be in good agreement with the smoothed array of experimental values.

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This paper presents a generalized approach to design an electromagnetically coupled microstrip ring antenna for dual-band operation. By widening two opposite sides of a square ring antenna, its fractional bandwidth at the primary resonance mode can be increased significantly so that it may be used for practical applications. By attaching a stub to the inner edge of the side opposite to the feed arm, some of the losses in electrical length caused by widening can be regained. More importantly, this addition also alters the current distribution on the antenna and directs radiations at the second resonant frequency towards boresight. It has also been observed that for the dual frequency configurations studied, the ratio of the resonant frequencies (center dot r(2)center dot center dot r(1)) can range between 1.55 and 2.01. This shows flexibility in designing dual frequency antennas with a desired pair of resonant frequencies.

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The incorporation of DNA into nucleosomes and higher-order forms of chromatin in vivo creates difficulties with respect to its accessibility for cellular functions such as transcription, replication, repair and recombination. To understand the role of chromatin structure in the process of homologous recombination, we have studied the interaction of nucleoprotein filaments, comprised of RecA protein and ssDNA, with minichromosomes. Using this paradigm, we have addressed how chromatin structure affects the search for homologous DNA sequences, and attempted to distinguish between two mutually exclusive models of DNA-DNA pairing mechanisms. Paradoxically, we found that the search for homologous sequences, as monitored by unwinding of homologous or heterologous duplex DNA, was facilitated by nucleosomes, with no discernible effect on homologous pairing. More importantly, unwinding of minichromosomes required the interaction of nucleoprotein filaments and led to the accumulation of circular duplex DNA sensitive to nuclease P1. Competition experiments indicated that chromatin templates and naked DNA served as equally efficient targets for homologous pairing. These and other findings suggest that nucleosomes do not impede but rather facilitate the search for homologous sequences and establish, in accordance with one proposed model, that unwinding of duplex DNA precedes alignment of homologous sequences at the level of chromatin. The potential application of this model to investigate the role of chromosomal proteins in the alignment of homologous sequences in the context of cellular recombination is considered.