14,643 research outputs found

    Asymmetric Hydrogenation in Water by a Rhodium Complex of Sulfonated 2,2'-Bis(diphenylphosphino)-1,1'-binaphthyl (binap)

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    The synthesis of sulfonated 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (binap) is reported; a rhodium complex of this ligand is the first to perform asymmetric hydrogenation in neat water with optical yields as high as those obtained in nonaqueous solvent

    Will mobile video become the killer application for 3G? - an empirical model for media convergence

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    Mobile carriers have continually rolled out 3G mobile video applications to increase their revenue and profits. The presumption is that video is superior to the already successful SMS, ringtones, and pictures, and can create greater value to users. However, recent market surveys revealed contradicting results. Motivated by this discrepancy, we propose in this paper a parsimonious model for user acceptance of mobile entertainment as digital convergence. Integrating research on Information Systems, Flow, and Media Psychology, we take a unique approach to user acceptance of digital convergence - platform migration. Our key proposition is that the interaction between media types and the platform-specific constraints is the key determinant of user evaluation. Particularly, users' involvement in the media is determined by both the entertaining time span on the original platform and the attentional constraint of the new platform. The mismatch between the two spans can result in lower level involvement, which in turn cause no or even negative user emotional responses. The model was tested with empirical data. We discuss the theoretical contributions, strategic and design implications, and future research directions derived from this theoretical framewor

    Evaluation of matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) for the Identification of Group B Streptococcus.

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    Objective Group B Streptococcus (GBS) is a leading cause of neonatal meningitis and sepsis worldwide. Intrapartum antibiotics given to women carrying GBS are an effective means of reducing disease in the first week of life. Rapid and reliable tests are needed to accurately identify GBS from these women for timely intrapartum antibiotic administration to prevent neonatal disease. Many laboratories now use matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) by direct plating or cell lysis for the identification of GBS isolates. The cell lysis step increases time to results for clinical samples and is more complex to perform. Therefore, we seek to evaluate the sensitivity and specificity of the quicker and more rapid direct plating method in identifying GBS. Results We directly compared swab isolates analysed by both direct plating and cell lysis method and demonstrated that direct plating has a sensitivity and specificity of 0.97 and 1, respectively, compared to an additional cell lysis step. We demonstrated that MALDI-TOF MS can be successfully used for batch processing by the direct plating method which saves time. These results are reassuring for laboratories worldwide who seek to identify GBS from swabs samples as quickly as possible

    NGC1052 - A study of the pc-scale twin jet

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    We present results of a VLBA multi-frequency study of the pc-scale twin jet in NGC1052. We observed this object at epoch 1998.99 with the VLBA at 5, 8.4, 22 and 43 GHz both in total and linearly polarized intensity. The spectral analysis confirms the necessity of a free-free absorbing medium, obscuring the innermost part of both jets. At 5 GHz we found a compact linearly polarized emission region at the base of the eastern jet with a degree of polarization of 1.5%. At higher frequencies there is no evidence for polarization in our data. A core shift analysis constrains the position of the central engine to ~0.03 pc. The shift rates of the apparent core position with frequency confirm the strong influence of free-free absorption in conjunction with steep pressure gradients at the bases of both jets.Comment: Proceedings of the conference "SRT: the impact of large antennas on Radio Astronomy and Space Science", Cagliari, Italy, 7-10 November 2001, in press; 6 pages, 5 figures, needs srt_style.st

    Scaling by 5 on a 1/4-Cantor Measure

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    Each Cantor measure (\mu) with scaling factor 1/(2n) has at least one associated orthonormal basis of exponential functions (ONB) for L^2(\mu). In the particular case where the scaling constant for the Cantor measure is 1/4 and two specific ONBs are selected for L^2(\mu), there is a unitary operator U defined by mapping one ONB to the other. This paper focuses on the case in which one ONB (\Gamma) is the original Jorgensen-Pedersen ONB for the Cantor measure (\mu) and the other ONB is is 5\Gamma. The main theorem of the paper states that the corresponding operator U is ergodic in the sense that only the constant functions are fixed by U.Comment: 34 page

    Post traumatic stress disorder among former child soldiers attending a rehabilitative service and primary school education in northern Uganda.

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    Background: This study was prompted by the psychiatric hospitalization of 12 former child soldiers of the Lord's Resistance Army (LRA) at a rehabilitation school in northern Uganda with a case of mass psychotic behavior. Objectives: To report the prevalence of post-traumatic stress disorder, depressed mood, and associated risk factors. Methods: Data on post-traumatic stress disorder, depressed mood, physical disabilities, socio-demographic variables, and the children's war experiences were collected in face-to-face interviews using the Harvard Trauma Questionnaire (HTQ), a modified Hopkins Symptoms Check-List (HSCL), and a 15-item War Trauma Experience Check-list (WTECL-15). Data was analyzed with SPSS version 11.0. Results: There were 58 girls and 44 boys. Eighty nine children (87.3%) reported having experienced ten or more war-related traumatic psychological events; 55.9% of the children suffered from symptoms of post-traumatic stress disorder, 88.2%, symptoms of depressed mood and 21.6% had various forms of physical disability. Nearly half of the children (42.2%) reported a positive family history of severe mental illness; 10.8%, a family history of suicide; 22.5%, a family history of suicide attempt; and 45.1%, a family history of alcohol abuse. Children who experienced 10 or more traumatic war events were more likely than the rest to experience depressed mood. Return through a reception center or through a cleansing ritual did not protect against depression. Discussion: Post-traumatic stress disorder among former LRA child soldiers at a rehabilitation centre in northern Uganda is presented. The report highlights the huge unmet need for psychological services among former child soldiers of the LRA. African Health Sciences Vol. 8 (3) 2008: pp. 136-14
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