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Negative Sign (negative + sign)
Selected AbstractsAntral Red Streaking is a Negative Endoscopic Sign for Helicobacter Pylori InfectionDIGESTIVE ENDOSCOPY, Issue 3 2002Takao Kawabe Background: ,One of the most important endoscopic findings for the diagnosis of chronic gastritis is erythema. Erythema is classified into two groups: spotted or scattered erythema and linear erythema. We feel that red streaking has a tendency to be found on the apparently normal gastric mucosa without inflammation. Methods: ,To evaluate this association prospectively, we conducted the present study in 1513 consecutive patients undergoing endoscopy. Helicobacter pylori infection was assessed by rapid urease test, culture, pathological test, serological test and urea breath test using 13C. Results: ,Of these patients, red streaking was recognized in 94 patients (6.2%). All of the tests showed very low prevalence (0,3.5%) of H. pylori infection in patients with red streaking whereas positive results were obtained recognized in 42,49% of 94 age-sex-matched patients without red streaking. Additionally, no peptic-ulcer diseases, such as gastric ulcer/ulcer scar and duodenal ulcer/ulcer scar, were found in the patients with red streaks. In conclusion, red streaking is a negative sign for H. pylori infection and peptic-ulcer diseases. Conclusions: ,The understanding of these results might also improve the effort and cost-effectiveness of endoscopic examinations by avoiding unnecessary further testing. [source] Indirect nuclear spin,spin coupling constants in 1,2-diboretane-3-ylidene, a homoaromatic system with , and , 3c/2e bonds.MAGNETIC RESONANCE IN CHEMISTRY, Issue 6 2004Comparison of experimental data with calculations using density functional theory (DFT) Abstract The non-classical 1,2-diboretane-3-ylidene 1a was studied by 13C and 29Si NMR spectroscopy in order to obtain coupling constants 1J(13C,11B) and 1J(29Si,13C). The magnitudes of 1J(13C,11B) were deduced from linewidth measurements in low-temperature 13C and 11B NMR spectra. Calculation of the coupling constants for model compounds related to 1a, using DFT methods based on optimized geometries [B3LYP/6,311+G(d,p)], gave data in agreement with the experiments. Furthermore, the calculations predict for the first time a negative sign of 1J(13C,11B) which mirrors the bonding situation in 1 as described by theory. Copyright © 2004 John Wiley & Sons, Ltd. [source] Foreign debt and economic growthTHE ECONOMICS OF TRANSITION, Issue 3 2001Shuanglin Lin This paper empirically examines the relationship between government foreign debt and the growth rate of per capita GDP based on a total sample of 77 countries, as well as sub-samples of various regions. Cross-sectional estimates of the coefficient of foreign debt based on the total sample have a negative sign, but are not always statistically significant. Available data from African countries indicate that foreign debt and the growth rate of per capita GDP were negatively related at a high level of significance. For industrialized and Latin American sub-samples, this relationship is negative but statistically insignificant. The sub-sample Asian and other developing countries show a positive but insignificant relationship. JEL classification: F34, H6, O23. [source] Comparing performances of logistic regression and neural networks for predicting melatonin excretion patterns in the rat exposed to ELF magnetic fieldsBIOELECTROMAGNETICS, Issue 2 2010Samad Jahandideh Abstract Various studies have been reported on the bioeffects of magnetic field exposure; however, no consensus or guideline is available for experimental designs relating to exposure conditions as yet. In this study, logistic regression (LR) and artificial neural networks (ANNs) were used in order to analyze and predict the melatonin excretion patterns in the rat exposed to extremely low frequency magnetic fields (ELF-MF). Subsequently, on a database containing 33 experiments, performances of LR and ANNs were compared through resubstitution and jackknife tests. Predictor variables were more effective parameters and included frequency, polarization, exposure duration, and strength of magnetic fields. Also, five performance measures including accuracy, sensitivity, specificity, Matthew's Correlation Coefficient (MCC) and normalized percentage, better than random (S) were used to evaluate the performance of models. The LR as a conventional model obtained poor prediction performance. Nonetheless, LR distinguished the duration of magnetic fields as a statistically significant parameter. Also, horizontal polarization of magnetic fields with the highest logit coefficient (or parameter estimate) with negative sign was found to be the strongest indicator for experimental designs relating to exposure conditions. This means that each experiment with horizontal polarization of magnetic fields has a higher probability to result in "not changed melatonin level" pattern. On the other hand, ANNs, a more powerful model which has not been introduced in predicting melatonin excretion patterns in the rat exposed to ELF-MF, showed high performance measure values and higher reliability, especially obtaining 0.55 value of MCC through jackknife tests. Obtained results showed that such predictor models are promising and may play a useful role in defining guidelines for experimental designs relating to exposure conditions. In conclusion, analysis of the bioelectromagnetic data could result in finding a relationship between electromagnetic fields and different biological processes. Bioelectromagnetics 31:164,171, 2010. © 2009 Wiley-Liss, Inc. [source] Site-Selective Formation of Optically Active Inclusion Complexes of Alkoxo-Subphthalocyanines with ,-Cyclodextrin at the Toluene/Water InterfaceCHEMISTRY - A EUROPEAN JOURNAL, Issue 16 2006Kenta Adachi Abstract Several subphthalocyanine derivatives that contain an alkoxo substituent as an axial ligand (RO-Subpc, R = 9-anthracenemethyl, benzyl, phenyl, 3,5-dimethylbenzyl, 3,5-dimethylphenyl, 4-methylbenzyl, and 4-methylphenyl) were synthesized. The formation of inclusion complexes of RO-Subpc with ,-CD in DMSO and at the toluene/water interface was investigated by UV/Vis absorption spectroscopy, induced circular dichroism (ICD), and nuclear magnetic resonance (NMR) measurements. Interfacial tension measurements suggested that ,-CD adsorbed as a monolayer at the toluene/water interface and probably orientated towards the toluene phase with its primary face. The 1:1 composition of ,-CD,RO-Subpc inclusion complexes was confirmed in DMSO and at the toluene/water interface for BzO-Subpc, PhO-Subpc, MeBzO-Subpc, and MePhO-Subpc. A 2:1 inclusion complex of AnO-Subpc formed in DMSO. The observed ICD spectra of ,-CD,RO-Subpc inclusion complexes are discussed with respect to molecular modeling and the simulation based on Tinoco,Kirkwood theory. Interestingly, the ICD spectra of ,-CD,BzO-Subpc and ,-CD,MeBzO-Subpc inclusion complexes exhibited a negative sign in DMSO and a positive sign at the toluene/water interface. This reversal of the ICD sign strongly suggests a difference in the structure of the inclusion complexes: ,-CD at the interface formed the inclusion complex with its primary face, whereas the secondary face of ,-CD bound favorably to RO-Subpc in DMSO. [source] Tourism demand response by residents of Latin American countriesINTERNATIONAL JOURNAL OF TOURISM RESEARCH, Issue 1 2009Manuel Vanegas Sr Abstract A general-to-specific methodology was used to build international tourism demand models by residents from Argentina, Brazil, Colombia and Venezuela to Aruba. We seek to evaluate demand parameters, especially elasticity values, which were disaggregated on a country-to-country basis. We also aim to learn more about the structure and important variables and investigate the process of adjustment. The study has provided new and compelling evidence that, in the short run, residents in developing countries respond rationally and substantially to economic stimulus. The short-run income elasticity ranges from the low of 1.52 for Venezuela to the high of 2.34 for Argentina. These results indicate that Aruba will benefit differently from income increases in these four Latin American countries. The coefficients of the price variable had the expected negative signs, inelastic in the short-run for all countries but significant at the 5% level for Venezuela only. Any deliberate effort to expand tourist arrivals will require a much larger decline in prices than would be the case in the presence of short-run elastic response. The adjustment elasticity, being less than one, suggests that a period of more than one year is required for Latin American residents to fully adjust their tourism decisions in response to demand shocks. This study would seem to provide some useful information about international tourism demand from developing to developing countries that could form a very good and solid basis for analyses and policy action. Copyright © 2008 John Wiley & Sons, Ltd. [source] The darker side of groupsJOURNAL OF NURSING MANAGEMENT, Issue 4 2007MIKE THOMAS BSc This paper examines the role of group interaction in the workplace and the impact of anxiety on group cohesion. It takes a psychoanalytical perspective and highlights how early learning within a familial setting influences later attitudes and behaviour at work. In particular the article focuses on the signs of negative group anxiety and how the manager can recognise anti-group culture. By recognising the negative signs the leader can also come to understand how the anti-group develops and thereby prevent the resulting disruptive behaviour. In some instances the perception of anti-group feelings and behaviour can also be altered so that the team leader can reach a positive outcome for the group dynamic and resultant team cohesion and collaboration. [source] Selectivity of nitro versus fluoro substitution in arenes in their reactions with charged O - and S -nucleophilesJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 6 2007Irina A. Khalfina Abstract The relative mobility of nitro and fluoro substituents in 1,3-dinitro- and 1-fluoro-3-nitrobenzenes, 3,5-dinitro- and 3-fluoro-5-nitrobenzotrifluorides under the action of the nucleophiles (2ArYH)·K2CO3 and ArY,K+ in solution and the nucleophiles ArYH·K2CO3 (Y,=,O, S) under heterogeneous conditions was studied by a competitive method in DMF at 40,140,°C. The unique dependences of ,,H, on ,,S, and ,,H, on ,,G, were determined for all the substrates and nucleophiles. The dependence of the mechanistic pathway on the nucleophile is discussed. Two results are relevant to the reactions studied: (i) substituent effects in the nucleophiles (2ArYH)·K2CO3 and ArYH·K2CO3 on the activation entropies suggest that the entropy favours the displacement of nitro group; (ii) the negative signs of ,,H, and ,,S, for the reactions of the nucleophiles ArY,K+ indicate that the enthalpy determines the displacement of nitro group. It is concluded that the selectivity of the reactions with aryloxide and arylthioxide ions cannot be explained by the hard,soft acid,base principle only. Copyright © 2007 John Wiley & Sons, Ltd. [source] The demand for electricity in PakistanOPEC ENERGY REVIEW, Issue 1 2009Muhammad Arshad Khan This paper examines the patterns of electricity demand in Pakistan over the period 1970,2006 using autoregressive distributed lag technique to cointegration. Long run and short-run price and income elasticities are examined for the national level and for the three major consumer's categories,households, industry and agriculture. The overall results suggest that income and price elasticities possess expected signs at aggregate and disaggregate levels in the long run as well as in the short run. The error correction terms possess expected negative signs and are highly significant with reasonable magnitudes. Furthermore, the estimated long run and short-run electricity demand functions remains stable over the sample period. The results thus convey important information to the agents operating in the electricity market regarding the pricing policies and helps in planning the future strategy of electricity demand management. [source] | ||||||||||||||||