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Search Results: 1 - 10 of 210552 matches for " L Brand "
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The effect of technology on learner attention and achievement in the classroom
G Bester,L Brand
South African Journal of Education , 2013,
Abstract: The objective of this investigation was to determine the effect of technology on attention and achievement within a classroom context, taking motivation and concentration into account as well. Lessons in Geography, English and Mathematics were presented to an experimental and a control group consisting of 23 and 22 Grade 8 learners, respectively. Technology was implemented for the experimental group but not for the control group. Significant differences were found between the average achievements of a group of learners, exposed to technology during a lesson, compared to a group not exposed to technology. Significant differences were also found between the average attention of a group of learners, exposed to technology during a lesson, compared to a group not exposed to technology. A high positive relationship was obtained between motivation and concentration and moderate to high positive correlations were obtained between attention, concentration and motivation, taken jointly as independent variables and achievement as the dependent variable.
A pulsed atomic soliton laser
L. D. Carr,J. Brand
Physics , 2004, DOI: 10.1103/PhysRevA.70.033607
Abstract: It is shown that simultaneously changing the scattering length of an elongated, harmonically trapped Bose-Einstein condensate from positive to negative and inverting the axial portion of the trap, so that it becomes expulsive, results in a train of self-coherent solitonic pulses. Each pulse is itself a non-dispersive attractive Bose-Einstein condensate that rapidly self-cools. The axial trap functions as a waveguide. The solitons can be made robustly stable with the right choice of trap geometry, number of atoms, and interaction strength. Theoretical and numerical evidence suggests that such a pulsed atomic soliton laser can be made in present experiments.
Theory of Multidimensional Solitons
L. D. Carr,Joachim Brand
Physics , 2007, DOI: 10.1007/978-3-540-73591-5_7
Abstract: We review a number of topics germane to higher-dimensional solitons in Bose-Einstein condensates. For dark solitons, we discuss dark band and planar solitons; ring dark solitons and spherical shell solitons; solitary waves in restricted geometries; vortex rings and rarefaction pulses; and multi-component Bose-Einstein condensates. For bright solitons, we discuss instability, stability, and metastability; bright soliton engineering, including pulsed atom lasers; solitons in a thermal bath; soliton-soliton interactions; and bright ring solitons and quantum vortices. A thorough reference list is included.
Spontaneous soliton formation and modulational instability in Bose-Einstein condensates
L. D. Carr,J. Brand
Physics , 2003, DOI: 10.1103/PhysRevLett.92.040401
Abstract: The dynamics of an elongated attractive Bose-Einstein condensate in an axisymmetric harmonic trap is studied. It is shown that density fringes caused by self-interference of the condensate order parameter seed modulational instability. The latter has novel features in contradistinction to the usual homogeneous case known from nonlinear fiber optics. Several open questions in the interpretation of the recent creation of the first matter-wave bright soliton train [Strecker {\it et al.} Nature {\bf 417} 150 (2002)] are addressed. It is shown that primary transverse collapse, followed by secondary collapse induced by soliton--soliton interactions, produce bursts of hot atoms at different time scales.
Synthesis, Structural Study and Spectroscopic Characterization of a Quinolin-8-Yloxy Derivative with Potential Biological Properties  [PDF]
Elida Romano, María V. Castillo, Jorgelina L. Pergomet, Juan Zinczuk, Silvia A. Brandán
Open Journal of Synthesis Theory and Applications (OJSTA) , 2013, DOI: 10.4236/ojsta.2013.21002
Abstract:

We have prepared the (5-chloro-quinolin-8-yloxy) acetic acid and characterized it by using infrared, Raman and multi-dimensional nuclear magnetic resonance spectroscopies. The density functional theory (DFT) together with the 6-31G* and 6-311++G** basis sets were used to study its structure and vibrational properties. Three stable conformations of the compound were theoretically determined in gas phase and probably these conformations are present in the solid phase. The harmonic vibrational wavenumbers for the optimized geometries were calculated at the same theory levels. For a complete assignment of the observed bands in the vibrational spectra, the DFT calculations were combined with Pulays scaled quantum mechanical force field (SQMFF) methodology in order to fit the theoretical wavenumber values to the experimental ones. Besides, the force constants of the three conformers of (5-chloro-quinolin-8-yloxy) acetic acid were calculated and compared with those obtained by us for the 2-(quinolin-8-yloxy) acetic acid. In addition, the characteristics of the electronic delocalization of those structures were performed by using natural bond orbital (NBO), while the corresponding topological properties of electronic charge density are analysed by employing Baders

A uni?o da alma e do intelecto na filosofia de Plotino
Brand?o, Bernardo G. S. L.;
Kriterion: Revista de Filosofia , 2007, DOI: 10.1590/S0100-512X2007000200013
Abstract: one of the most important features of plotinus' ethical system is his doctrine of the union between soul and intellect: this union is the goal of purification procedures, the summit of dialectic practice and the basis of mystical experience. but, being inferior to intellect, how is it possible for the soul to achieve this union? this paper is an attempt at searching for the plotinian explanation for this problem.
Paradoxical increase of exploratory behavior in the elevated plus-maze by rats exposed to two kinds of aversive stimuli
Morato, S.;Brand?o, M.L.;
Brazilian Journal of Medical and Biological Research , 1997, DOI: 10.1590/S0100-879X1997000900010
Abstract: albino rats were submitted to a 24-h period of social isolation (individual housing) combined with 0, 1, 2 or 3 twenty-four-hour periods of exposure to different vivaria (novelty) and tested in the elevated plus-maze. results, reported as mean ± sem for n = 12, show that the time (in seconds) spent in the open arms by rats exposed to novelty for 0, 1, 2 and 3 days was 28.3 ± 4.4, 31.6 ± 3.2, 29.1 ± 3.5 and 25.0 ± 3.3, respectively, when grouped in the same vivarium; 29.6 ± 2.7, 7.6 ± 2.1, 9.6 ± 4.4 and 28.5 ± 3.7 when grouped in different vivaria; 2.9 ± 1.1, 1.8 ± 1.0, 2.7 ± 1.1 and 0 ± 0 when isolated in the same vivarium, and 2.6 ± 1.1, 31.5 ± 8.2, 24.8 ± 4.2 and 0 ± 0 when isolated in different vivaria. the number of entries into the open and closed arms followed a similar trend. this indicates that, separately, both exposure to novelty and isolation are aversive manipulations. paradoxically, when novelty was combined with a concomitant 24-h period of social isolation prior to testing, the decrease in exploratory behavior caused by either of the two aversive manipulations alone was reverted. these results are indicative that less intense anxiety triggers mechanisms mediating less energetic behavior such as freezing, while higher levels trigger mechanisms mediating more vigorous action, such as flight/fight behavior, since the combination of two aversive situations resulted in more exploratory behavior than with either alone. they are also suggestive of habituation to the effects of novelty, since exposure to it for 3 days produced exploratory behavior similar to that of controls
A review of non-obstetric spontaneous pneumo-mediastinum and subcutaneous emphysema
M Brand, B Bizos, L Burnell
South African Journal of Surgery , 2011,
Abstract: A man in his early twenties was admitted from the streets. He was hallucinating and incoherent. His vital signs were normal and there was no sign of injury. There was subcutaneous emphysema over the neck and anterior chest. The breath sounds were good and the heart sounds were audible. Chest X-ray showed extensive subcutaneous emphysema extending into the neck, but no pneumomediastinum or pneumothorax. A Hexabrix swallow demonstrated no leak. A computed tomography (CT) scan showed extensive surgical emphysema but no underlying pathology. Over the following 48 hours he was treated with a 40% oxygen mask. He remained stable and the surgical emphysema settled completely. Urine testing for cannabis and cocaine were negative. He was certified and admitted to a closed psychiatric ward. No further surgical problems occurred during the following month.
Die verband tussen beroepsbesluitloosheid, vrees vir gebondenheid en beroepsidentiteit
L. J. Goosen,H. J. Brand
South African Journal of Industrial Psychology , 1997, DOI: 10.4102/sajip.v23i2.623
Abstract: The relationship between career indecisiveness, fear for commitment and vocational identity. This study examined the correlation between the constructs career indecision, fear of commitment and vocational identity. Ninety-eight under-graduate university students served as research participants and completed the Career Decision Scale (CDS), the Vocational Identity Scale (VIS) and the Fear of Commitment Questionnaire (FOCQ). The results indicated that the scores on the CDS were significantly related (p is smaller than 0,05) to the scores on the VIS and the FOCQ. Support was obtained for the important role of the construct of identity in the explanation of career indecisiveness. Opsomming In die onderhawige studie is die aard van die verband tussen die konstrukte beroepsbesluitloosheid, vrees vir gebondenheid en beroepsidentiteit ondersoek. Ag-en-egentig voorgraadse universiteitstudente is by die studie betrek. Die ondersoekgroep het die Career Decision Scale (CDS), die Vocational Identity Scale (VIS) en die Fear of Commitment Questionnaire (FOCQ) voltooi. Die resultate het aangetoon dat daar beduidende verband (p is kleiner as 0,05) tussen die verkree totaaltellings op die CDS, die VIS en die FOCQ bestaan het. Die belangrike rol wat die konstruk identiteit in die verklaring van beroepsbesluitloosheid speel word deur die bevindings van die onderhawige studie ondersteun.
Amizade e focos de atividade na universidade
Agnaldo Garcia,Lívia Ramos Brand?o
Interpersona : An International Journal on Personal Relationships , 2010,
Abstract: The aim of this study was to investigate foci of activity which were perceived by students of public and private universities in Vitoria metropolitan area as relevant to the establishment and maintenance of their friendships. Participants were 32 college students aged 17 to 21 years, 16 from a public university (UPU) and 16 students from a private university (UPA). The following topics were investigated: (a) friends network, (b) the origin of friends, (c) friendship and neighborhood (d) general activities; (e) specific activities; (f) communication and conversation; (g) university, friendship and dating; (h) university life and old friends; (i) the influence of university on friendships. From a descriptive base, data showed friendship as a relationship involving a wide range of interactions, keeping dialectical relationship with these interactions and social groups. The friendships still relate dialectically with the physical environment, including the physical structure of the university, and the socio-cultural, including rules, schedules and activity plans of the university and local traditions.
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