658 research outputs found
The role and attributes of entrepreneurs at South Africa’s largest arts festival.
The Klein Karoo National Arts Festival (KKNK) in Oudtshoorn, South Africa, is the largest
arts festival in South Africa. The purpose of this research was to determine the attributes and role of the
entrepreneurs at the Klein Karoo National Arts Festival. This was done by means of a questionnaire
survey (N=249). After data capturing was completed, two factor analyses were conducted. The first
factor analysis revealed six factors (entrepreneurial attributes), namely organisational skills, resourcefulness, self-edification, explorative, acquired skill and drive, of which resourcefulness had the highest
mean value. The second factor analysis identified the role of entrepreneurs at KKNK and revealed three
primary roles, namely festival promotion, product promotion and income generation, of which product
promotion had the highest mean value. This is the first time that the roles of entrepreneurs at festivals
were investigated in South AfricaEl Festival de las Artes Nacional Klein Karoo (KKNK) en Oudtshoorn, Sudáfrica, es el mayor festival de las artes en el sur de África. El propósito de esta investigación fue determinar las características y el papel de los empresarios en éste. Lo cual se hizo por medio de una encuesta (N = 249).
Después de la captura de datos, se realizaron dos análisis. El análisis factorial reveló por primera vez seis
factores (atributos empresariales): capacidad de organización, capacidad de auto-edificación, de exploración, adquirió la habilidad y la unidad, de la que el ingenio tuvo el valor más alto. El análisis del segundo
factor identificado como el papel de los empresarios en el KKNK reveló tres papeles principales, a saber,
la promoción de festivales, promoción de productos y generación de ingresos, de los cuales tenían la
promoción de los productos de mayor valor. Esta es la primera vez que se ha investigado el papel de los
empresarios en los festivales de Sudáfrica
Biliary tract visualization using near-infrared imaging with indocyanine green during laparoscopic cholecystectomy: results of a systematic review
Contains fulltext :
174508.pdf (publisher's version ) (Open Access)BACKGROUND: Near-infrared imaging with indocyanine green (ICG) has been extensively investigated during laparoscopic cholecystectomy (LC). However, methods vary between studies, especially regarding patient selection, dosage and timing. The aim of this systematic review was to evaluate the potential of the near-infrared imaging technique with ICG to identify biliary structures during LC. METHODS: A comprehensive systematic literature search was performed. Prospective trials examining the use of ICG during LC were included. Primary outcome was biliary tract visualization. Risk of bias was assessed using ROBINS-I. Secondly, a meta-analysis was performed comparing ICG to intraoperative cholangiography (IOC) for identification of biliary structures. GRADE was used to assess the quality of the evidence. RESULTS: Nineteen studies were included. Based upon the pooled data from 13 studies, cystic duct (Lusch et al. in J Endourol 28:261-266, 2014) visualization was 86.5% (95% CI 71.2-96.6%) prior to dissection of Calot's triangle with a 2.5-mg dosage of ICG and 96.5% (95% CI 93.9-98.4%) after dissection. The results were not appreciably different when the dosage was based upon bodyweight. There is moderate quality evidence that the CD is more frequently visualized using ICG than IOC (RR 1.16; 95% CI 1.00-1.35); however, this difference was not statistically significant. CONCLUSION: This systematic review provides equal results for biliary tract visualization with near-infrared imaging with ICG during LC compared to IOC. Near-infrared imaging with ICG has the potential to replace IOC for biliary mapping. However, methods of near-infrared imaging with ICG vary. Future research is necessary for optimization and standardization of the near-infrared ICG technique
Resolutions of C^n/Z_n Orbifolds, their U(1) Bundles, and Applications to String Model Building
We describe blowups of C^n/Z_n orbifolds as complex line bundles over
CP^{n-1}. We construct some gauge bundles on these resolutions. Apart from the
standard embedding, we describe U(1) bundles and an SU(n-1) bundle. Both
blowups and their gauge bundles are given explicitly. We investigate ten
dimensional SO(32) super Yang-Mills theory coupled to supergravity on these
backgrounds. The integrated Bianchi identity implies that there are only a
finite number of U(1) bundle models. We describe how the orbifold gauge shift
vector can be read off from the gauge background. In this way we can assert
that in the blow down limit these models correspond to heterotic C^2/Z_2 and
C^3/Z_3 orbifold models. (Only the Z_3 model with unbroken gauge group SO(32)
cannot be reconstructed in blowup without torsion.) This is confirmed by
computing the charged chiral spectra on the resolutions. The construction of
these blowup models implies that the mismatch between type-I and heterotic
models on T^6/Z_3 does not signal a complication of S-duality, but rather a
problem of type-I model building itself: The standard type-I orbifold model
building only allows for a single model on this orbifold, while the blowup
models give five different models in blow down.Comment: 1+27 pages LaTeX, 2 figures, some typos correcte
A dynamic inequality generation scheme for polynomial programming
Hierarchies of semidefinite programs have been used to approximate or even solve polynomial programs. This approach rapidly becomes computationally expensive and is often tractable only for problems of small size. In this paper, we propose a dynamic inequality generation scheme to generate valid polynomial inequalities for general polynomial programs. When used iteratively, this scheme improves the bounds without incurring an exponential growth in the size of the relaxation. As a result, the proposed scheme is in principle scalable to large general polynomial programming problems. When all the variables of the problem are non-negative or when all the variables are binary, the general algorithm is specialized to a more efficient algorithm. In the case of binary polynomial programs, we show special cases for which the proposed scheme converges to the global optimal solution. We also present several examples illustrating the computational behavior of the scheme and provide comparisons with Lasserre’s approach and, for the binary linear case, with the lift-and-project method of Balas, Ceria, and Cornuejols
Characterizing the universal rigidity of generic frameworks
A framework is a graph and a map from its vertices to E^d (for some d). A
framework is universally rigid if any framework in any dimension with the same
graph and edge lengths is a Euclidean image of it. We show that a generic
universally rigid framework has a positive semi-definite stress matrix of
maximal rank. Connelly showed that the existence of such a positive
semi-definite stress matrix is sufficient for universal rigidity, so this
provides a characterization of universal rigidity for generic frameworks. We
also extend our argument to give a new result on the genericity of strict
complementarity in semidefinite programming.Comment: 18 pages, v2: updates throughout; v3: published versio
An Iterative Scheme for Valid Polynomial Inequality Generation in Binary Polynomial Programming
Semidefinite programming has been used successfully to build hierarchies of convex relaxations to approximate polynomial programs. This approach rapidly becomes computationally expensive and is often tractable only for problems of small sizes. We propose an iterative scheme that improves the semidefinite relaxations without incurring exponential growth in their size. The key ingredient is a dynamic scheme for generating valid polynomial inequalities for general polynomial programs. These valid inequalities are then used to construct better approximations of the original problem. As a result, the proposed scheme is in principle scalable to large general combinatorial optimization problems. For binary polynomial programs, we prove that the proposed scheme converges to the global optimal solution for interesting cases of the initial approximation of the problem. We also present examples illustrating the computational behaviour of the scheme and compare it to other methods in the literature
Lymph Node Negative Colorectal Cancers with Isolated Tumor Deposits Should Be Classified and Treated As Stage III
BACKGROUND: The prognostic role of pericolic or perirectal isolated tumor deposits (ITDs) in node-negative colorectal cancer (CRC) patients is unclear. Rules to define ITDs as regional lymph node metastases changed in subsequent editions of the TNM staging without substantial evidence. Aim of this study was to investigate the correlation between ITDs and disease recurrence in stage II and III CRC patients. MATERIALS AND METHODS: The medical files of 870 CRC patients were reviewed. Number, size, shape, and location pattern of all ITDs in node-negative patients were examined in relation to involvement of vascular structures and nerves. The correlation between ITDs and the development of recurrent disease was investigated. RESULTS: Disease recurrence was observed in 50.0% of stage II patients with ITDs (13 of 26), compared with 24.4% of stage II patients without ITDs (66 of 270) (P <.01). Disease-free survival of ITD-positive stage II patients was comparable with that of stage III patients. Also within stage III, more recurrences were observed in ITD-positive patients compared with ITD-negative patients (65.1 vs. 39.1%, respectively). No correlation was found between size of ITDs and disease recurrence. More recurrences were seen in patients with irregularly shaped ITDs compared with patients with 1 or more smooth ITDs present. CONCLUSIONS: Because of the high risk of disease recurrence, all node-negative stage II patients with ITDs, regardless of size and shape, should be classified as stage III, for whom adjuvant chemotherapy should be considere
Re-HEDP : pharmacokinetic characterization, clinical and dosimetric evaluation in osseous metastatic patients with two levels of radiopharmaceutical dose
BACKGROUND: A study for pain relief therapy with (188)Re-HEDP was done in patients with bone metastases secondary to breast and prostate cancer. MATERIALS AND METHODS: Patients received 1.3 or 2.2 GBq, in single or multiple doses. Platelets, white and red cells were evaluated during 11 weeks. Pharmacokinetic characterization was done from blood and urine samples for 5 patients along 24 hours. Urinary excretion was evaluated in other 16 patients during 6 hours. Bone uptake was estimated as remaining activity in whole body. Scintigraphic images were acquired at 2 and 24 hs post-administration. Absorbed dose in bone marrow was estimated with Mirdose3. Analgesics intake and pain score were daily recorded. Tumour markers (PSA, and Tn-structure) were monitored in 9 patients during 4 to 6 months. Single doses of low activity (1.3 GBq) were given to twelve patients. Nine patients received multiple doses. RESULTS: All except one patient had normal levels of platelets, white and red cells. Remaining dose in blood at 2 hours was 9%. Urinary elimination was 58%. Bone uptake at 24 hours was 43% (mean value; n = 5). No changes of the haematological parameters were detected along follow-up period. Pain relief was evidenced by decrease or supression of opioid analgesic and by subjective index. PSA showed a decrease in prostate cancer patients (n = 4). Tn-structure showed a significant increase after 4 to 8 months. CONCLUSION: Single or multiple dose scheme could be safely used, with administered activity of (188)Re-HEDP up to 60 mCi, with low bone marrow absorbed doses
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