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Rotation
Kinds of Rotation Terms modified by Rotation Selected AbstractsIMPACT OF RISK AVERSION ON THE OPTIMAL ROTATION WITH STOCHASTIC PRICENATURAL RESOURCE MODELING, Issue 3 2008PEICHEN GONG Abstract This paper examines the effect of risk aversion on the optimal rotation when the stumpage price is stochastic. Assuming that the stumpage price is normally distributed, we show that the optimal rotation under risk aversion may be shorter than, equal to, or longer than the corresponding optimal rotation under risk neutrality. Which of these cases holds true depends on the interest rate and the real regeneration cost, and can be determined based on the marginal variance (i.e., the derivative of the variance function with respect to rotation age) evaluated at the optimal rotation under risk neutrality. Furthermore, we show that there exists a monotone continuous curve, which divides the interest rate-regeneration cost space into two regions where risk aversion affects the optimal rotation differently. For a given interest rate, risk aversion shortens (prolongs) the optimal rotation if the regeneration cost lies below (above) the curve. Along the separating curve the optimal rotation under risk aversion coincides with the optimal rotation under risk neutrality. Two examples are presented to demonstrate the separating curve and the impacts of risk aversion on the optimal rotation. [source] Localized Gas Puffing Control of Edge Rotation and Electric FieldCONTRIBUTIONS TO PLASMA PHYSICS, Issue 1-3 2004P. J. Catto No abstract is available for this article. [source] Influence of the position of the foot on MRI signal in the deep digital flexor tendon and collateral ligaments of the distal interphalangeal joint in the standing horseEQUINE VETERINARY JOURNAL, Issue 5 2009M. SPRIET Summary Reasons for performing study: Hyperintense signal is sometimes observed in ligaments and tendons of the equine foot on standing magnetic resonance examination without associated changes in size and shape. In such cases, the presence of a true lesion or an artifact should be considered. A change in position of a ligament or tendon relative to the magnetic field can induce increased signal intensity due to the magic angle effect. Objectives: To assess if positional rotation of the foot in the solar plane could be responsible for artifactual changes in signal intensity in the collateral ligaments of the distal interphalangeal joint and in the deep digital flexor tendon. Methods: Six isolated equine feet were imaged with a standing equine magnetic resonance system in 9 different positions with different degrees of rotation in the solar plane. Results: Rotation of the limb induced a linear hyperintense signal on all feet at the palmar aspect of one of the lobes of the deep digital flexor tendon and at the dorsal aspect of the other lobe. Changes in signal intensity in the collateral ligaments of the distal interphalangeal joint occurred with rotation of the limb only in those feet where mediolateral hoof imbalance was present. Conclusions: The position and conformation of the foot influence the signal intensity in the deep digital flexor tendon and in the collateral ligaments of the distal interphalangeal joint. Potential relevance: The significance of increased signal intensity in the deep digital flexor tendon and in the collateral ligaments of the distal interphalangeal joint should be interpreted with regard to the position and the conformation of the foot. [source] Self-Assembly, Structure and Solution Dynamics of Tetranuclear Zn2+ Hydrazone [2×2] Grid-Type ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 4 2006Mihail Barboiu Abstract We describe the self-assembly processes as well as the structural and physico-chemical properties of [2×2]Zn2+4 grid complexes involving the bis-tridentate ligands 7,12, based on bis(hydrazone)pyrimidine complexation subunits and octahedrally coordinated Zn2+ ions. The NMR spectroscopic data and the X-ray crystal structure results indicate that in solution and in the solid state the complexes 13,18 adopt a very compact arrangement providing stable [2×2] hydrazone-grid arrays. The ,,, stacking between the phenyl ring and the hydrazone units of the perpendicular ligands in the complexes induces a perfect orthogonal arrangement suitable for applications in self-organized metallosupramolecular systems. Zinc complexes provide an opportunity to study the acid,base chemistry without the added effects due to paramagnetism or redox chemistry. The intermediate protonated grids undergo relatively rapid proton exchange on the NMR timescale, the presence of a sharp pyrimidine proton resonance suggesting that there is significant delocalization of the negative charge along the backbone of the ligand. Rotation of the phenyl ring is observed. It involves probably a mechanism in which one of the ligands partially dissociates allowing the initially intercalated phenyl group to rotate, before recoordination of the terminal pyridine. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] A New Model of Light-Powered Chiral Molecular Motor with Higher Speed of Rotation, Part 1 , Synthesis and Absolute StereostructureEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2005Takuma Fujita Abstract To develop a molecular motor with a higher speed of rotation, a new model light-powered chiral molecular motor 2 of five-membered ring type was designed, and the motor rotation isomers (,)- 2a and (,)- 2c were directly synthesized in enantiopure forms for the first time from the ketone (+)- 8. The precursor alcohols 9 and 10 were enantioresolved by the camphorsultam-dichlorophthalic acid (CSDP acid; 3) method, and their absolute configurations were determined by X-ray crystallographic analysis of the CSDP ester (,)- 11b and chemical correlations. The enantiopure ketone (S)-(+)- 8 formed from (1S,2S)-(+)- 9 or (1R,2S)-(,)- 10 was subjected to the McMurry reaction with TiCl3/LiAlH4, yielding the motor rotation isomers [CD(,)257.8]-(2S,2,S)-(M,M)-(E)-(,)- 2a and [CD(,)270.0]-(2S,2,S)-(M,M)-(Z)-(,)- 2c. These studies enabled us unambiguously to determine the absolute stereostructure of the motor 2, which is of critical importance for control over the direction of motor rotation. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Axial Rotation of the Lower Human Spine by Rhythmic Torques Automatically Generated at the Resonant FrequencyEXPERIMENTAL PHYSIOLOGY, Issue 3 2003E. Geoffrey Walsh Subjects sat on a ,Balans' chair supported by the shaft of a large torque generator. The lower but not the upper part of the body was free to make to/fro movements maintained by feeding back a modified velocity signal to the generator. The stiffness could be increased by the use of a position signal. Using the equations for a torsion pendulum the good linearity observed in relationship to the applied forces allowed stiffness, inertia, damping, critical damping and the damping factor to be determined in absolute terms. The method enables parameters relevant to back function and problems to be evaluated. Eleven adults acted as subjects. [source] Improving Auditor Independence Through Selective Mandatory RotationINTERNATIONAL JOURNAL OF AUDITING, Issue 2 2002Miles B. Gietzmann When an auditor receives significant fee income from one client it has often been suggested that reappointment concerns may dilute auditors incentives to maintain independence from management. A possible response to this issue could be to mandate the rotation of auditors. However this is costly since new auditors must repeatedly invest in learning a new clients accounting system. In this research we build a model to formally analyze this trade-off. We find that the desirability of rotation depends critically upon characteristics of the audit market structure and to what extent an individual client dominates an auditors' client portfolio defined in terms of total fees. We show that although rotation is costly, in audit markets with relatively few large clients (thin markets), the resulting improved incentives for independence outweigh the associated costs. Our research is timely because although historically it may not have been economically desirable to adopt mandatory rotation, currently with increased corporate merger activity taking place, for instance in the oil sector, markets may now have become sufficiently thin to warrant the introduction of rotation. [source] Evolution of an accretionary complex along the north arm of the Island of Sulawesi, IndonesiaISLAND ARC, Issue 1 2004Yusuf Surachman Djajadihardja Abstract Seismic reflections across the accretionary prism of the North Sulawesi provide excellent images of the various structural domains landward of the frontal thrust. The structural domain in the accretionary prism area of the North Sulawesi Trench can be divided into four zones: (i) trench area; (ii) Zone A; (iii) Zone B; and (iv) Zone C. Zone A is an active imbrication zone where a decollement is well imaged. Zone B is dominated by out-of-sequence thrusts and small slope basins. Zone C is structurally high in the forearc basin, overlain by a thick sedimentary sequence. The subducted and accreted sedimentary packages are separated by the decollement. Topography of the oceanic basement is rough, both in the basin and beneath the wedge. The accretionary prism along the North Sulawesi Trench grew because of the collision between eastern Sulawesi and the Bangai,Sula microcontinent along the Sorong Fault in the middle Miocene. This collision produced a large rotation of the north arm of Sulawesi Island. Rotation and northward movement of the north arm of Sulawesi may have resulted in southward subduction and development of the accretionary wedge along North Sulawesi. Lateral variations are wider in the western areas relative to the eastern areas. This is due to greater convergence rates in the western area: 5 km/My for the west and 1.5 km/My for the east. An accretionary prism model indicates that the initiation of growth of the accretionary prism in the North Sulawesi Trench occurred approximately 5 Ma. A comparison between the North Sulawesi accretionary prism and the Nankai accretionary prism of Japan reveals similar internal structures, suggesting similar mechanical processes and structural evolution. [source] Impact of Soil Tillage and Crop Rotation on Barley (Hordeum vulgare) and Weeds in a Semi-arid EnvironmentJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 6 2004H. Z. Ghosheh Abstract Experiments were conducted to evaluate the effect of mouldboard- or chisel-ploughing and rotations on barley crops and associated weeds in a semi-arid location. Two primary soil tillage operations and eight crop rotation-tillage operation combinations were evaluated over two successive seasons. Drought conditions prevailed (<152 mm annual precipitation) and affected the measured parameters. Barley grown in mouldboard-ploughed plots had higher biomass compared with chisel-ploughed plots. Barley grain yield was greater in mouldboard-ploughed plots in a fallow-fallow-barley rotation. Weed species densities varied between tillage systems and rotations. Density of Hordeum marinum, for example, was high in fallow-barley-fallow in chisel-ploughed plots, and was high under more continuous fallow in mouldboard-ploughed plots. Similar variations were also observed in weed fresh weights and in numbers of seed produced. The results describe the productivity of barley under extremely dry conditions, where an advantage for mouldboard ploughing was observed. The results also indicate the complexity of weed communities in their response towards different tillage-rotation combinations. [source] Can High-Risk Older Drivers Be Identified Through Performance-Based Measures in a Department of Motor Vehicles Setting?JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 1 2006Karlene K. Ball PhD OBJECTIVES: To evaluate the relationship between performance-based risk factors and subsequent at-fault motor vehicle collision (MVC) involvement in a cohort of older drivers. DESIGN: Prospective cohort study. SETTING: Motor Vehicle Administration (MVA) field sites in Maryland. PARTICIPANTS: Of the 4,173 older drivers invited to participate in the study, 2,114 individuals aged 55 to 96 agreed to do so. These analyses focus on 1,910 individuals recruited through MVA field sites. MEASUREMENTS: Gross Impairment Screening Battery, which included Rapid Pace Walk, Head/Neck Rotation, Foot Tap, Arm Reach, Cued Recall, Symbol Scan, Visual Closure subtest of the Motor Free Visual Perception Test (MVPT), Delayed Recall, and Trail Making Test with an Abbreviated Part A and standard Part B; Useful Field of View (UFOV®) subtest 2; a Mobility Questionnaire; and MVC occurrence. RESULTS: In drivers aged 55 and older with intact vision (20/70 far visual acuity and 140° visual field), age, sex, history of falls, and poorer cognitive performance, as measured using Trails B, MVPT, and UFOV subtest 2, were predictive of future at-fault MVC involvement. After adjusting for annual mileage, participants aged 78 and older were 2.11 as more likely to be involved in an at-fault MVC, those who made four or more errors on the MVPT were 2.10 times as likely to crash, those who took 147 seconds or longer to complete Trails B were 2.01 times as likely to crash, and those who took 353 ms or longer on subtest 2 of the UFOV were 2.02 times as likely to incur an at-fault MVC. Older adults, men, and individuals with a history of falls were more likely to be involved in subsequent at-fault MVCs. CONCLUSION: Performance-based cognitive measures are predictive of future at-fault MVCs in older adults. Cognitive performance, in particular, is a salient predictor of subsequent crash involvement in older adults. High-risk older drivers can be identified through brief, performance-based measures administered in a MVA setting. [source] Hydrodynamic Cavitation: Characterization of a Novel Design with Energy Considerations for the Inactivation of Saccharomyces cerevisiae in Apple JuiceJOURNAL OF FOOD SCIENCE, Issue 6 2008P.J. Milly ABSTRACT:, A Shockwave PowerÔ Reactor consisting of an annulus with a rotating pock-marked inner cylinder was used to induce hydrodynamic cavitation in calcium-fortified apple juice flowing in the annular space. Lethality on Saccharomyces cerevisiae was assessed at processing temperatures of 65 and 76.7 °C. Details of the novel equipment design were presented and energy consumption was compared to conventional and pulsed electric fields processing technologies. The mean log cycle reduction of S. cerevisiae was 6.27 CFU/mL and all treatments resulted in nonrecoverable viable cells. Induced lethality from hydrodynamic cavitation on S. cerevisiae exceeded the predicted values based on experimentally determined thermal resistance. Rotation of 3000 and 3600 rpm at flow rates greater than 1.0 L/min raised product temperature from 20 to 65.6 or 76.7 °C, respectively, and energy input was less than 220 kJ/kg. Conversion efficiency from electrical to thermal was 55% to 84%. Hydrodynamic cavitation enhanced lethality of spoilage microorganisms in minimally processed juices and reduced energy usage. [source] Estimating the supply response of cotton and cereal crops in smallholder production systems: recent evidence from MaliAGRICULTURAL ECONOMICS, Issue 5 2009Jeffrey D. Vitale Cotton; Supply response; Rotation; Mali Abstract Cotton is one of the most important crops in West Africa and is a major catalyst of economic development in rural areas, but the sector has suffered from a decline in the world cotton price after 1999. This article exploits an unusual data set following 82 farmers over 14 years, from 1994 through 2007, to estimate a Nerlovian supply response model for cotton, maize, sorghum, and millet in long-term rotation. The resulting system of equations is estimated with two-stage least squares (2SLS), showing that this sample of Malian cotton producers have responded to prices in a relatively inelastic manner, with supply elasticities only about one-half of those estimated for producers in developed countries. Policy reforms could help producers respond more easily to prices changes, as well as to raise average productivity levels. [source] 3D coronary motion tracking in swine models with MR tracking cathetersJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2009Ehud J. Schmidt PhD Abstract Purpose To develop MR-tracked catheters to delineate the three-dimensional motion of coronary arteries at high spatial and temporal resolution. Materials and Methods Catheters with three tracking microcoils were placed into nine swine. During breath-holds, electrocardiographic (ECG)-synchronized 3D motion was measured at varying vessel depths. 3D motion was measured in American Heart Association left anterior descending (LAD) segments 6,7, left circumflex (LCX) segments 11,15, and right coronary artery (RCA) segments 2,3, at 60,115 beats/min heart rates. Similar-length cardiac cycles were averaged. Intercoil cross-correlation identified early systolic phase (ES) and determined segment motion delay. Results Translational and rotational motion, as a function of cardiac phase, is shown, with directionality and amplitude varying along the vessel length. Rotation (peak-to-peak solid-angle RCA ,0.10, LAD ,0.06, LCX ,0.18 radian) occurs primarily during fast translational motion and increases distally. LCX displacement increases with heart rate by 18%. Phantom simulations of motion effects on high-resolution images, using RCA results, show artifacts due to translation and rotation. Conclusion Magnetic resonance imaging (MRI) tracking catheters quantify motion at 20 fps and 1 mm3 resolution at multiple vessel depths, exceeding that available with other techniques. Imaging artifacts due to rotation are demonstrated. Motion-tracking catheters may provide physiological information during interventions and improve imaging spatial resolution. J. Magn. Reson. Imaging 2009;29:86,98. © 2008 Wiley-Liss, Inc. [source] Development of garnet porphyroblasts by multiple nucleation, coalescence and boundary misorientation-driven rotationsJOURNAL OF METAMORPHIC GEOLOGY, Issue 3 2001R. Spiess Abstract Two types of garnet porphyroblast occur in the Schneeberg Complex of the Italian Alps. Type 1 porphyroblasts form ellipsoidal pods with a centre consisting of unstrained quartz, decussate mica and small garnet grains, and a margin containing large garnet grains. Orientation contrast imaging using the scanning electron microscope shows that the larger marginal garnet grains comprise a number of orientation subdomains. Individual garnet grains without subdomains are small (< 50 µm), faceted and idioblastic, and have simple zoning profiles with Ca-rich cores and Ca-poor rims. Subdomains of larger garnet grains are similar in size to the individual, small garnet grains. Type 2 porphyroblasts comprise only ellipsoidal garnet, with small subdomains in the centre and larger subdomains at the margin. Each subdomain has its own Ca high, Ca dropping towards subdomain boundaries. Garnet grains, with or without subdomains, all have the same Ca-poor composition at rims in contact with other minerals. The compositional zonation patterns are best explained by simultaneous, multiple nucleation, followed by growth and amalgamation of individual garnet grains. The range of individual garnet and garnet subdomain sizes can be explained by a faster growth rate at the porphyroblast margin than in the centre. The difference between Type 1 and Type 2 porphyroblasts is probably related to the growth rate differential across the porphyroblast. Electron backscatter diffraction shows that small, individual garnet grains are randomly oriented. Large marginal garnet grains and subdomain-bearing garnet grains have a strong preferred orientation, clustering around a single garnet orientation. Misorientations across subdomain boundaries are small and misorientation axes are randomly oriented with respect to crystallographic orientations. The only explanation that fits the observational data is that individual garnet grains rotated towards coincident orientations once they came into contact with each other. This process was driven by the reduction of subdomain boundary energy associated with misorientation loss. Rotation of garnet grains was accommodated by diffusion in the subdomain boundary and diffusional creep and rigid body rotation of other minerals (quartz and mica) around the garnet. An analytical model, in which the kinetics of garnet rotation are controlled by the rheology of surrounding quartz, suggests that, at the conditions of metamorphism, the rotation required to give a strong preferred orientation can occur on a similar time-scale to that of porphyroblast growth. [source] Effects of rotation on measurement of lower limb alignment for knee osteotomyJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 6 2004Hideo Kawakami Abstract The purposes of this study were to clarify the effects of rotation on two-dimensional measurement of lower limb alignment for knee osteotomy using a three-dimensional method and to determine whether this 3-D simulation method could help with planning of knee osteotomy. We developed computer software to calculate femorotibial angle (FTA) and hip,knee,ankle angle (HKA) and simulate knee osteotomy from a CT-based 3-D bone model of the lower limb. Lower limb rotation on anteroposterior long-standing radiographs was measured by superimposing the 3-D bone models. Changes in alignment with limb rotation were calculated using the software. FTA after virtual closed-wedged osteotomy was measured for a hypothetical case of a rotation error of the osteotomy plane in reattaching the proximal cutting surface to the distal cutting surface. For 31 varus knees in 20 patients with medial compartment arthritis, the mean rotation angle, relative to the epicondylar axis, with variable limb position was 7.4 ± 3.9° of internal rotation (mean ± SD), ranging from 8° of external rotation to 14° of internal rotation; the mean changes in FTA and HKA were 3.5 ± 2.2° (range, 0.4,8.6) and 1.6 ± 1.3° (range, 0.2,4.9), respectively. The FTA "flexion angle" (lateral view alignment from neutral AP) and the absolute HKA "flexion angle" correlated with the change in FTA and HKA with limb rotation, respectively (FTA, R = 0.999; HKA, R = 0.993). The mean change in FTA after virtual closed-wedged osteotomy was 3.2° for internal and external 10° rotation errors in reattaching the osteotomy plane. Rotation may affect measurement of lower limb alignment for knee osteotomy, and 3-D methods are preferable for surgical planning. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] Rotation speed and stellar axis inclination from p modes: how CoRoT would see other sunsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2006J. Ballot ABSTRACT In the context of future space-based asteroseismic missions, we have studied the problem of extracting the rotation speed and the rotation-axis inclination of solar-like stars from the expected data. We have focused on slow rotators (at most twice solar rotation speed), first, because they constitute the most difficult case and, secondly, because some of the Convection Rotation and planetary Transits (CoRoT) main targets are expected to have slow rotation rates. Our study of the likelihood function has shown a correlation between the estimates of inclination of the rotation axis i and the rotational splitting ,, of the star. By using the parameters, i and ,,,=,, sin i, we propose and discuss new fitting strategies. Monte Carlo simulations have shown that we can extract a mean splitting and the rotation-axis inclination down to solar rotation rates. However, at the solar rotation rate we are not able to correctly recover the angle i, although we are still able to measure a correct ,,, with a dispersion less than 40 nHz. [source] Opioid Rotation in the Management of Chronic Pain: Where Is the Evidence?PAIN PRACTICE, Issue 2 2010K.C.P. Vissers MD Abstract The management of chronic pain remains a challenge because of its complexity and unpredictable response to pharmacological treatment. In addition, accurate pain management may be hindered by the prejudice of physicians and patients that strong opioids, classified as step 3 medications in the World Health Organization ladder for cancer pain management, are reserved for the end stage of life. Recent information indicates the potential value of strong opioids in the treatment of chronic nonmalignant pain. There are, up until now, insufficient data to provide indications about which opioid to use to initiate treatment or the dose to be used for any specific pain syndrome. The strong inter-patient variability in opioid receptor response and in the pharmacokinetic and pharmacodynamic behavior of strong opioids justifies an individual selection of the appropriate opioid and stepwise dose titration. Clinical experience shows that switching from one opioid to another may optimize pain control while maintaining an acceptable side effect profile or even improving the side effects. This treatment strategy, described as opioid rotation or switch, requires a dose calculation for the newly started opioid. Currently, conversion tables and equianalgesic doses are available. However, those recommendations are often based on data derived from studies designed to evaluate acute pain relief, and sometimes on single dose studies, which reduces this information to the level of an indication. In daily practice, the clinician needs to titrate the optimal dose during the opioid rotation from a reduced calculated dose, based on the clinical response of the patient. Further research and studies are needed to optimize the equianalgesic dosing tables. [source] Resistance of Pakistani field populations of spotted bollworm Earias vittella (Lepidoptera: Noctuidae) to pyrethroid, organophosphorus and new chemical insecticidesPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 4 2009Mushtaq Ahmad Abstract BACKGROUND: The spotted bollworm Earias vittella (Fab.) is a serious pest of cotton and okra in Pakistan. Owing to persistent use of insecticides, this pest has developed resistance, especially to pyrethroids. The present studies aimed at determining the extent of resistance to pyrethroid, organophosphorus and new chemical insecticides in Pakistani populations of E. vittella. RESULTS: Field populations of E. vittella were monitored at Multan, Pakistan, from 1999 to 2007 for their resistance against six pyrethroid, four organophosphorus and six new chemical insecticides using a leaf-dip bioassay. Of the pyrethroids, resistance was generally low to zeta-cypermethrin and moderate to high or very high to cypermethrin, deltamethrin, esfenvalerate, bifenthrin and lambda-cyhalothrin. Resistance to organophosphates chlorpyrifos, profenofos, triazophos and phoxim was recorded at very low to low levels. Among new chemicals, E. vittella had no or a very low resistance to spinosad, emamectin benzoate and methoxyfenozide, a very low to low resistance to abamectin, a very low to moderate resistance to indoxacarb and a moderate resistance to chlorfenapyr. CONCLUSION: The results indicate a lack of cross-resistance between pyrethroid and organophosphorus insecticides in E. vittella. Rotation of insecticides showing no, very low or low resistance, but belonging to different insecticide classes with unrelated modes of action, may prevent or mitigate insecticide resistance in E. vittella. Copyright © 2009 Society of Chemical Industry [source] Microscopic study of carrier transport in the organic semiconductor zinc-phthalocyaninePHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3-4 2010João Piroto Duarte Abstract Nominally undoped zinc-phthalocyanine (ZnPc) was investigated using Muon Spin Rotation (,SR) to probe microscopic carrier transport properties. The study focused on the relaxation of the positive muon's polarisation produced by spin-flip scattering with charge carriers. An energy of 71(8) meV was found for the temperature activation of carrier jumps, a value that does not match the activation energies known in ZnPc from electrical measurements, and that was attributed to a fast transport component in this material. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Information and Incentives Inside the Firm: Evidence from Loan Officer RotationTHE JOURNAL OF FINANCE, Issue 3 2010ANDREW HERTZBERG ABSTRACT We present evidence that reassigning tasks among agents can alleviate moral hazard in communication. A rotation policy that routinely reassigns loan officers to borrowers of a commercial bank affects the officers' reporting behavior. When an officer anticipates rotation, reports are more accurate and contain more bad news about the borrower's repayment prospects. As a result, the rotation policy makes bank lending decisions more sensitive to officer reports. The threat of rotation improves communication because self-reporting bad news has a smaller negative effect on an officer's career prospects than bad news exposed by a successor. [source] The Bicorannulenyl Dianion: A Charged Overcrowded Ethylene,ANGEWANDTE CHEMIE, Issue 41 2010David Eisenberg Bicorannulenyl, ein großes Biaryl bestehend aus zwei ,schüsselförmigen" Corannulenen, wird nach Reduktion zum Dianion in ein sterisch überfrachtetes Ethylen umgewandelt (siehe Bild). DFT-Rechnungen und NMR-spektroskopische Untersuchungen lassen den Doppelbindungscharakter der zentralen Bindung zwischen den beiden Untereinheiten erkennen. Drei stabile Diastereomere, die sich durch Inversion und Rotation um die zentrale Bindung ineinander umwandeln lassen, wurden gefunden. [source] Optische Stabilität axial-chiraler push-pull-substituierter Buta-1,3-diene: Effekt einer einzelnen Methylgruppe auf der Oberfläche von C60,ANGEWANDTE CHEMIE, Issue 20 2010Michio Yamada Dr. Hohe Barrieren der Rotation um die Chiralitätsachse zeichnen axial-chirale push-pull-substituierte Buta-1,3-dien-Chromophore aus, die mit vicinal methylierten Fullerenen verknüpft sind. Dadurch gelingen die Trennung der Enantiomere und die Bestimmung ihrer absoluten Konfiguration durch Vergleich von experimentellen und berechneten Circulardichroismus-Spektren. Die Methylgruppe auf der Fullerenoberfläche ist entscheidend für die hohen Rotationsbarrieren. [source] Ultra-cool and extra-vigorous: Rotation and activity in Mand L dwarfsASTRONOMISCHE NACHRICHTEN, Issue 10 2007A. Reiners, Article first published online: 27 DEC 200 Abstract The study of rotation and activity in low-mass stars or brown dwarfs of spectral classes M and L has seen enormous progress during the last years. I summarize the results from different works that measured activity, rotation, and sometimes magnetic fields. The generation of magnetic activity seems to be unchanged at the threshold to completely convective stars, i.e. no change in the efficiency of the magnetic dynamos is observed. On the other hand, a sudden change in the strength of rotational braking appears at the threshold mass to full convection, and strong evidence exists for rotational braking weakening with lower mass. A probable explanation is that the field topology changes from dipolar to small scale structure as the objects become fully convective. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Determination of the Absolute Configurations of Natural Products via Density Functional Theory Calculations of Vibrational Circular Dichroism, Electronic Circular Dichroism, and Optical Rotation: The Iridoids Plumericin and Isoplumericin.CHEMINFORM, Issue 37 2007P. J. Stephens Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Controlling the Speed of Rotation in Molecular Motors.CHEMINFORM, Issue 13 2006Dramatic Acceleration of the Rotary Motion by Structural Modification. Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Remarkably Slow Rotation about a Single Bond between an sp3 -Hybridised Carbon Atom and an Aromatic Ring without ortho SubstituentsCHEMISTRY - A EUROPEAN JOURNAL, Issue 9 2009Sarah Murrison Abstract Look, noorthosubstituents! A series of polycycles were prepared by using a three-component Joullié,Ugi reaction. The rate of rotation about the bond between a highly hindered bridgehead and a phenyl ring with no ortho substituents was measured, and was highly dependent on the substitution. Rotamer half-lives of up to 21,h at 298,K were observed (see figure). Rotamers resulting from this restricted rotation were isolated for the first time. A series of polycycles was prepared by using a three-component Joullié,Ugi reaction. The rate of rotation about the bond between a highly hindered bridgehead and a phenyl ring with no ortho substituents was measured by using, in general, variable-temperature HPLC. The rate of rotation was highly dependent on substitution and rotamer half-lives of up to 21,h at 298,K were observed. Insights into the effect of substitution on the rate of rotation were gleaned through electronic structure calculations on closely related derivatives. Rotamers resulting from restricted rotation about a bond between an sp3 -hybridised carbon atom and a phenyl ring with no ortho substituents were isolated for the first time, and the equilibration of the separated rotamers was followed by using analytical HPLC. It was demonstrated, for the first time, that a highly hindered environment for the sp3 -hybridised atom is sufficient for slow bond rotation about a single bond between sp3 - and sp2 -hybridised carbon atoms. [source] Dissecting the Hindered Rotation of EthaneCHEMPHYSCHEM, Issue 12 2009David Asturiol With a twist: The rotational barrier of ethane (see picture) is analyzed in terms of atomic and diatomic contributions of the energy. No charge-localized reference state is necessary. Hyperconjugation effects give rise to different individual energy components that cancel almost completely. The picture of attributing the barrier to the repulsion between the hydrogen atoms is legitimate. [source] Conformational Analysis of Molecular Machines: Internal Rotation and Enantiomerization in Triptycyl[3]heliceneCHEMPHYSCHEM, Issue 8 2008Miquel Llunell Dr. No independent rotation: Detailed analysis of the PES for triptycyl[3]helicene (see figure) shows that rotation around the helicene,triptycyl bond cannot be considered independently from other degrees of freedom when analyzing its stereodynamic behavior. The possibility of enantiomerization of the helicene pawl results in more complex dynamics than previously expected. [source] Solvent Effect on Optical Rotation: A Case Study of Methyloxirane in WaterCHEMPHYSCHEM, Issue 12 2006Parag Mukhopadhyay Explicit solute,solvent interactions: MD simulations and TD-DFT are used to determine the solvent dependence of the optical rotatory dispersion (ORD) for methyloxirane in water (see figure). The inclusion of explicit solute,solvent interactions is essential to describe the influence of the solvent on the OR of the system and the MD simulations provide a suitable means to analyze and predict chiroptical solvation effects. [source] Fingerprints of Damped Quantum Rotation Observed in Solid-State Proton NMR SpectraCHEMPHYSCHEM, Issue 4 2006Peter Gutsche Dr. Abstract 1H NMR spectra of the methyl group in an oriented crystal sample of methylmalonic acid with all three non-methyl protons replaced by deuterons are interpreted in terms of the damped quantum rotation (DQR) theory of NMR line shapes. The DQR approach offers a perfect theoretical reproduction of the observed spectra while the conventional Alexander-Binsch line-shape model shows evident defects in the present case. The temperature trends of the quantities characterizing the coherent and incoherent dynamics of the methyl group in the DQR approach (the effective tunnelling frequency and two coherence-damping rates) derived from the spectra are fairly reproduced using a model reported previously. The present findings provide further evidence of limitations to the validity of the common belief that molecular rate processes in condensed phases are necessarily classical. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||