bluuebunny/crossref_metadata_2025 huggingface dataset:
Organizational Learning in Project-Based Companies: A Process Thinking Approach
Authors: Koskinen Kaj U.
Published: April 2012

Although a traditional project model is clearly useful for laying out the patterns of relationships surrounding a project, it does not provide the temporally embedded accounts that enable us to understand how organizational learning takes place. The process thinking perspective offers a means to solving this problem. This article provides an analysis of how different processes interact dynamically in order to benefit project-based companies' organizational learning. Two findings from this study are: (1) organizational learning is a dynamic concept that emphasizes the continually changing nature of a project-based company and (2) sensemaking and negotiation of meaning are ongoing processes in project-based companies.
Electrochemically induced charge transfer in platinum–silicon heterosystems
Authors: Bürstel Damian , Diesing Detlef
Published: April 2012

Electrochemical cyclovoltammetry experiments were carried out on the platinum surface of a platinum–silicon thin‐film device in sulfuric acid. The internal electronic barrier of the device allows the separation of ground state and excited state charge transfer events released by the electrochemical surface reaction. The traces of the device current show similar features as the cyclovoltammogram and can be discussed in terms of small deviations from the equilibrium state of the thin platinum film. The device current plotted as a function of the electrode potential shows a well‐defined shift of the baseline when hydrogen is adsorbed. This baseline shift may be originated by an adsorbate‐induced change of the chemical potential of the platinum film, thus influencing the internal field in the device (up to values of 23 mV).

magnified image

Plot of the electrochemical current and the device current as functions of the electrode potential.
Defect levels in SnS thin films prepared using chemical spray pyrolysis
Authors: Sajeesh T. H. , Jinesh K. B. , Rao M. , Kartha C. S. , Vijayakumar K. P.
Published: April 2012

The origin of various defect levels in the SnS thin films deposited using chemical spray pyrolysis (CSP) technique has been explored in this manuscript, by employing low‐temperature photoluminescence (PL) technique. Concentration of Sn in the samples was varied purposefully by ex situ diffusion in order to alter the defect levels. The acceptor level obtained at 0.22 eV from the Arrhenius plot, has been assigned as the defect level caused by the Sn vacancies present in the lattice. Two shallow donor levels are conclusively identified and their activation energies have been estimated. The present study could also unearth a trap level in the forbidden energy gap which was due to the oxygen contaminant occupied by the vacancy of Sn. This trap level could be removed by annealing the sample in vacuum or through the ex situ diffusion of Sn. Employing Kelvin probe force microscopy (KPFM), the work‐function of SnS was obtained as 4.925 eV, from which the position of the Fermi level could be assigned. Based on the present work, an energy level scheme for SnS thin films is proposed outlying origin of various defect levels.
Resonant Raman study of dye instability in dye‐sensitized TiO2 system: The effect of surface states
Authors: Wu Kunjie , Shen Kai , Liu Weifeng , Wu Liuer , Wang Deliang
Published: April 2012

The most critical problem in commercialization of the dye‐sensitized solar cell (DSSC) is its long‐term stability. Many factors contribute to the instability of a DSSC. In order to clarify the role of the surface defects on the cell instability, we modified the TiO2 surface chemical states, fabricated DSSCs with a very simple structure, and carried out resonant Raman scattering to monitor the dye degradation under open‐circuit condition. The results showed that the dye stability was very sensitive to the TiO2 surface states. The dye degradation can be described by an exponential decay law. The oxygen vacancy–Ti3+ chemical state enhanced the recombination of electron with the oxidized electrolyte, i.e., the electron in the TiO2 conduction band injected back to the electrolyte, and consequently enhanced the dye regeneration rate by I−, which came from the reduction of ${\rm I}_{3}^{- } $ with electrons. Under the open‐circuit condition the dye stability was increased when it was attached to a TiO2 surface with a relatively high percentage of oxygen vacancy–Ti3+ chemical state. The increased electron recombination occurred at the TiO2/electrolyte interface resulted in a much decreased open‐circuit voltage and short‐circuit current in a DSSC.
Parasitic absorption effect of metal nanoparticles in the dye‐sensitized solar cells
Authors: Yuan Li , Chen Fuyi , Zheng Chunfeng , Liu Jian , Alemu Negash
Published: April 2012

The parasitic absorption effect of metal nanoparticles in the dye‐sensitized solar cells (DSSC) was investigated using the finite difference time domain technique. It was shown that the conversion efficiency can be improved up to 15–20% in the DSSC device with an optimized metal nanoparticle array of 210 nm in diameter and 500 nm in period, but even under the optimized conditions, the absorption of metal nanoparticles take up about 20–30% of the total absorption of DSSC at visible wavelengths. The heat loss of smaller (70 nm) metal nanoparticles at visible light wavelengths is far greater than the electromagnetic energy scattered into the optical active dye‐sensitized medium. The possible direction was proposed to solve the metal parasitic absorption problem.
Electroluminescence from amorphous silicon/crystalline silicon solar cells and its temperature dependence
Authors: Brüggemann Rudolf
Published: April 2012

The quality of the amorphous silicon/crystalline silicon interface is decisive for efficient operation of amorphous silicon/crystalline silicon heterojunction solar cells. We investigate the electroluminescence from these heterojunction solar cells for a variation of interface properties. We detail electroluminescence results from temperature‐dependent simulations which show that the electroluminescence yield at constant current density is almost temperature‐independent for lower interface‐defect densities while for higher interface‐defect densities the electroluminescence yield decreases with decreasing temperature. In contrast to the influence of the front interface which does not change the spectral shape, the related inhomogeneous carrier profile distorts the spectrum so that conclusions can be drawn on the rear interface properties. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Shell model for REOx nanoclusters in amorphous SiO2: charge trapping and electroluminescence quenching
Authors: Tiagulskyi S. , Nazarov A. , Tyagulskii I. , Lysenko V. , Rebohle L. , Lehmann J. , Skorupa W.
Published: April 2012

In this work charge trapping and electroluminescence (EL) quenching in rare‐earth (RE) implanted SiO2 on Si as a function of injected charge into the dielectric were studied. The blocking of the luminescent REOX nanoclusters from the hot exciting electrons by negative charge trapping in a defect region (shell) located in the vicinity of the REOX nanocluster/SiO2 interface is considered as the main mechanism of EL quenching for small size (up to 10 nm) REOX nanoclusters. It is suggested that the increase of the nanoclusters size results in disordering of the SiO2 matrix but in a decrease of local blocking for excitation of the luminescent centers. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Correlation of nanostructure and charge transport properties of oxidized a ‐SiC:H films
Authors: Gordienko S. O. , Nazarov A. N. , Vasin A. V. , Rusavsky A. V. , Lysenko V. S.
Published: April 2012

This paper considers the influence of low temperature oxidation on structural and electrical properties of amorphous carbon‐rich a ‐Si1‐xCx:H thin films fabricated by reactive RF magnetron sputtering. It is shown that oxidation leads to formation of SiOx matrix with graphite‐like carbon inclusions. Such conductive precipitates has a strong effect on charge transport in oxidized a ‐Si1‐xCx:H films (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Percolation effect in structures with amorphous and crystalline silicon nanoclusters
Authors: Zhigunov Denis M. , Emelyanov Andrey V. , Timoshenko Victor Yu. , Sokolov Victor I. , Seminogov Vladimir N.
Published: April 2012

In this paper the correlations between optical, electrical and structural properties of ensembles of amorphous and crystalline silicon nanoclusters in silicon oxide matrix are explained in terms of percolation theory. SiOx (1 ≤ x < 2) thin films were deposited on silicon or quartz substrates by reactive evaporation of SiO powder and were subsequently thermally annealed at temperatures in the range from 450 to 1200 °C. Five sets of samples with different stoichiometry parameters x = 1.0, 1.1, 1.29, 1.56, 1.68 of initial SiOx were fabricated. The volume fraction of total excess silicon as well as the volume fraction of silicon nanocrystals in high temperature annealed structures are calculated for each sample set. It is found that samples with excess Si volume fraction of more than 16% (which is critical value in percolation theory) demonstrate a local maximum at about 500‐600 °C in the dependence of integrated photoluminescence intensity on annealing temperature, which is attributed to the first percolation threshold in the system of amorphous Si nanoclusters. In turn, the second percolation threshold is detected in the system of crystalline Si nanoclusters, when their volume fraction exceeds 16%. Such effect, resulted in dramatic increase of the electrical conductance of SiOx film, was registered experimentally for the set of samples with x = 1.0. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Improving BPH symptoms and sexual dysfunctions with a saw palmetto preparation? Results from a pilot trial
Authors: Suter Andreas , Saller Reinhard , Riedi Eugen , Heinrich Michael
Published: April 2012

In elderly men, benign prostatic hyperplasia (BPH) is a major risk factor for sexual dysfunctions (SDys). Additionally, the standard treatments for BPH symptoms, alpha blockers and 5‐alpha‐reductase inhibitors, cause SDys themselves. Preparations from saw palmetto berries are an efficacious and well‐tolerated symptomatic treatment for mild to moderate BPH and have traditionally been used to treat SDys. We conducted an open multicentric clinical pilot trial to investigate whether the saw palmetto berry preparation Prostasan® influenced BPH symptoms and SDys. Eighty‐two patients participated in the 8‐week trial, taking one capsule of 320 mg saw palmetto extract daily. At the end of the treatment, the International Prostate Symptom Score was reduced from 14.4 ± 4.7 to 6.9 ± 5.2 (p < 0.0001); SDys measured with the brief Sexual Function Inventory improved from 22.4 ± 7.2 to 31.4 ± 9.2 (p < 0.0001), and the Urolife BPH QoL‐9 sex total improved from 137.3 ± 47.9 to 195.0 ± 56.3 (p < 0.0001). Investigators' and patients' assessments confirmed the good efficacy, and treatment was very well tolerated and accepted by the patients. Correlation analyses confirmed the relationship between improved BPH symptoms and reduced SDys. This was the first trial with saw palmetto to show improvement in BPH symptoms and SDys as well. [Corrections made here after initial online publication.] Copyright © 2012 John Wiley & Sons, Ltd.
An analysis of the diurnal cycle of precipitation over Dakar using local rain‐gauge data and a general circulation model
Authors: Sane Y. , Bonazzola M. , Rio C. , Chambon P. , Fiolleau T. , Musat I. , Hourdin F. , Roca R. , Grandpeix J.‐Y. , Diedhiou A.
Published: April 2012

The representation of the diurnal cycle of local deep convection in two versions of the Laboratoire de Météorologie Dynamique–Zoom (LMDZ) General Circulation Model is evaluated using rainfall observations of a rain‐gauge network in Senegal. An interpretation of the observed rainfall diurnal modes is attempted by partitioning rainfall as a function of rain‐rate intensities and the origin, age and size of associated cloud systems. Our analysis shows a complex multipeak diurnal cycle and a large spatial variability over the rain‐gauge domain of typically 100 km. Our results are consistent with the picture of a diurnal cycle of high convective rain rates associated with young and small cloud systems generated in the vicinity of the rain gauges, peaking in late afternoon and superimposed with precipitation associated with long propagative mesoscale convective systems or squall lines with no preferential time over the rain‐gauge network. It is shown that these local observations of convection and rain can be used to evaluate the representation of the diurnal cycle of precipitation in a general circulation model with a typical horizontal resolution of 100 km. Two versions of the LMDZ model, including different parametrizations of boundary‐layer turbulence, convection and clouds, are compared with observations. In the new parametrization, considering the role of boundary‐layer thermals in deep convection preconditioning and the role of cold pools in its sustainment allows us realistically to shift the maximum of precipitation and cloud cover to late afternoon. Copyright © 2012 Royal Meteorological Society
Long‐term monitoring of French polarimetric radar data quality and evaluation of several polarimetric quantitative precipitation estimators in ideal conditions for operational implementation at C‐band
Authors: Figueras i Ventura Jordi , Boumahmoud Abdel‐Amin , Fradon Béatrice , Dupuy Pascale , Tabary Pierre
Published: April 2012

This article presents the evaluation of several polarimetric quantitative precipitation estimation (Pol‐QPE) algorithm candidates for operational implementation in the Météo‐France polarimetric weather radars (nine C‐band and one S‐band out of a total of 24 radars in 2011). Since the performance of the algorithms depends on both the quality of the polarimetric variables and the applied polarimetric processing, the article first describes the current polarimetric processing chain and then provides a comprehensive analysis of the quality of the polarimetric variables.

Three types of QPE algorithms have been studied at C‐band in ideal conditions (short ranges, no partial beam blocking, no vertical profile of reflectivity effects):

(i) algorithms based on simple Z‐R relationships with and without attenuation correction using the differential phase Φdp,

(ii) an algorithm based on reflectivity (Zh) and differential reflectivity (Zdr), and

(iii) algorithms based on specific differential phase (Kdp).

Evaluation against rain‐gauges, performed hourly, confirms the superiority of polarimetric algorithms as repeatedly reported in the literature. It also shows that the benefits brought by algorithms based on power variables, Zh and Zdr, are critically dependent upon the capability to correctly calibrate them. Long‐term monitoring shows that, with the current radar systems and operational calibration procedures, a stability of ±0.4 dB is achieved on Zdr. In that context, QPE algorithms based on Kdp, which are considered to be immune to partial beam blocking, calibration, attenuation, etc., are preferred for operational use until improvements are made to the calibration of Zdr. To this end, a hybrid algorithm based on attenuation‐corrected Zh for low rain rates and Kdp for higher rain rates has been designed and tested Copyright © 2012 Royal Meteorological Society
Interpreting an evaluation of the ECMWF global model with CloudSat observations: ambiguities due to radar reflectivity forward operator uncertainties
Authors: Di Michele Sabatino , Ahlgrimm Maike , Forbes Richard , Kulie Mark , Bennartz Ralf , Janisková Marta , Bauer Peter
Published: April 2012

This article explores the uncertainties associated with evaluating a global atmospheric model with radar reflectivity observations. A forward operator for radar reflectivity (ZmVar) is described and used for the comparison of the ECMWF global numerical weather prediction model short‐range forecasts with radar data from CloudSat. A sensitivity study is performed to determine which differences can be attributed to either specific radar forward operator assumptions or to deficiencies in the global model. The results show that model‐derived reflectivities are particularly sensitive to the definition of subgrid precipitation fraction, as precipitation dominates the radar reflectivity signal, but also to the choice of particle size distribution and scattering properties of the different hydrometeor categories. However, there are a number of consistent differences in the reflectivity comparison that are significantly larger than can be explained by the sensitivity tests. This suggests that these discrepancies are due to deficiencies in the model cloud and precipitation frequency of occurrence and hydrometeor water contents. These include too frequent occurrence at high altitudes, too low occurrence in the Southern Hemisphere storm track and an overestimate of rain in warm‐phase low cloud. The study shows the value of CloudSat for evaluating the model in terms of radar reflectivity and highlights the importance of taking into account forward operator uncertainties for both model evaluation and data assimilation applications. Copyright © 2012 Royal Meteorological Society
Does one‐photon photocyclization of trans‐diarylethylenes involve adiabatic trans‐to‐cis photoisomerization? potential energy surface calculations for 1‐styrylnaphthalene
Authors: Budyka Mikhayl F.
Published: April 2012

Potential energy surface (PES) for 1‐styrylnaphthalene was calculated by PM3 method for the S0 state and PM3‐CI(2x2) method with configuration interaction for the S1 state. Scanning PES along both isomerization and cyclization reaction coordinates enabled to reveal the minimum energy path (MEP) with low barriers on the S1 PES from E‐isomer to dihydrocyclophotoproduct (DHP). This is consistent with formation of the photocyclization product in one‐photon process during irradiation of E‐isomer. Additionally, the MEP was found to bypass the coordinate region of Z‐isomer, i.e. one‐photon E‐isomer‐to‐DHP photocyclization does not demand participation of the excited Z‐isomer. Therefore, adiabatic trans‐to‐cis isomerization is likely not an intermediate stage on the E‐isomer photocyclization pathway, and experimentally observed one‐photon formation of the DHP from the E‐isomer is likely not an evidence for adiabatic trans‐to‐cis photoisomerization, as it is usually assumed. According to the results obtained, two photochemical reactions of E‐isomer, photoisomerization to Z‐isomer and photocyclization to DHP, are not consecutive but parallel reactions with branching at perpendicular conformer on the S1 PES. © 2012 Wiley Periodicals, Inc.
Conformational analysis, tautomeric preference, intramolecular hydrogen bonding, and solvent effect on dinitrosamine: A quantum chemical study
Authors: Jahani Peyman Mohammadzadeh , Nowroozi Alireza
Published: April 2012

HF, B3LYP, and MP2 methods with the standard basis set, 6‐311++G(d,p), were used to study various aspects of dinitrosamine. These results were compared with the outcomes of G2 and CBS‐QB3 methods. First, the conformational analysis and characterization of equilibrium conformations, especially global minima, were performed. On the basis of relative energies, we found that the dinitroso tautomers are more stable than the nitroso‐hydroxy (NH) ones. This preference is well‐interpreted in terms of tautomerization process and nitrosamine resonance. Furthermore, the nature of OH···O intramolecular hydrogen bond (IMHB), in chelated forms of NH (NH‐11 and NH‐13) was comprehensively studied to evaluate the effect of hetero atoms (N) on the characteristic of IMHB systems. According to the results of isodesmic reaction method, the hydrogen bond energy of NH‐11 is greater than the malonaldehyde (MA) and NH‐13, whereas the electron density analysis and energy‐geometry correlation methods clearly predict that the hydrogen bond of NH‐11 is weaker than the MA. Additionally, the geometrical, atoms in molecules (AIM) and natural bond orbital's (NBO) parameters also emphasize on the MA as a chelated form with the strongest hydrogen bond. Finally, the solvent effects on the relative stability of selected dinitrosamine conformers are evaluated by different continuum (polarizable‐continuum model, isodensity polarizable continuum model, and self‐consistent isodensity polarizable continuum model), discrete and mixed solvent models. Theoretical results readily show that the potential energy surface of dinitrosamine, especially global minima, is strongly affected by the solvent. © 2012 Wiley Periodicals, Inc.
Computational simulations of hydrolysis of phosphazene oligomer utilizing atom‐centered density matrix propagation
Authors: Kroger Jessica L. , Fried Joel R. , Skelton Adam A.
Published: April 2012

Density functional theory (DFT) calculations, including the ab initio molecular dynamics method, atom‐centered density matrix propagation (ADMP), were used to investigate the hydrolysis reaction of a dichlorophosphazene trimer. The model trimer, intermediate structures and the product of the first step of hydrolysis, were optimized using DFT with the B3LYP density functional, followed by a 600 fs ADMP simulation. Natural bond order analysis (NBO) was used to determine atomic charges and occupancy of the bond orbitals and the lone pair orbitals of the molecule at various points along the simulation pathway. The simulation successfully shows dissociation of the trimer backbone into two distinct product molecules, shown through both increasing separation of the product units and through the more thorough NBO analysis of the bond orbitals. © 2012 Wiley Periodicals, Inc.
Differentiation of underivatized monosaccharides by atmospheric pressure chemical ionization quadrupole time‐of‐flight mass spectrometry
Authors: Zhu Zhenqian , Song Liguo , Bartmess John E.
Published: April 2012

RATIONALE

Differentiation of underivatized monosaccharides is essential in the structural elucidation of oligosaccharides which are closely involved in many life processes. So far, such differentiation has been usually achieved by electrospray ionization mass spectrometry (ESI‐MS). As an alternative to ESI‐MS, atmospheric pressure chemical ionization mass spectrometry (APCI‐MS) should provide complementary results.

METHODS

A quadrupole time‐of‐flight (QTOF) mass spectrometer with accurate mass measurement ability was used with an APCI heated nebulizer ion source because we believe that a recently published article using a single quadrupole mass spectrometer assigned incorrect identities for APCI ions from hexoses. Using APCI‐QTOF, the MS2andpseudo‐MS3mass spectra of 11 underivatized monosaccharides were obtained under various collision voltages. The mass spectra were carefully interpreted after accurate mass measurement.

RESULTS

Differentiation of three hexoses was achieved by different MS2spectra of their [M + NH4]+and [M − H]–ions. The MS2spectra of the [M + NH4]+ions were also used to distinguish methylα‐D‐glucose and methylβ‐D‐glucose, while thepseudo‐MS3spectra of the [M + H]+ions were utilized to differentiate the three hexosamine andN‐acetylhexosamine stereoisomers. Unique [M + O2]–ions were observed and their distinctive fragmentation patterns were utilized to differentiate the three hexosamine stereoisomers.

CONCLUSIONS

Although ESI coupled with single or triple quadrupole and ion trap mass spectrometers has been widely utilized in the differentiation of monosaccharides, this report demonstrated that APCI‐QTOF‐MS had its own advantages in achieving the same goal. Copyright © 2012 John Wiley & Sons, Ltd.
Non‐lithographic SERS Substrates: Tailoring Surface Chemistry for Au Nanoparticle Cluster Assembly
Authors: Adams Sarah M. , Campione Salvatore , Caldwell Joshua D. , Bezares Francisco J. , Culbertson James C. , Capolino Filippo , Ragan Regina
Published: April 2012

Near‐field plasmonic coupling and local field enhancement in metal nanoarchitectures, such as arrangements of nanoparticle clusters, have application in many technologies from medical diagnostics, solar cells, to sensors. Although nanoparticle‐based cluster assemblies have exhibited signal enhancements in surface‐enhanced Raman scattering (SERS) sensors, it is challenging to achieve high reproducibility in SERS response using low‐cost fabrication methods. Here an innovative method is developed for fabricating self‐organized clusters of metal nanoparticles on diblock copolymer thin films as SERS‐active structures. Monodisperse, colloidal gold nanoparticles are attached via a crosslinking reaction on self‐organized chemically functionalized poly(methyl methacrylate) domains on polystyrene‐block‐poly(methyl methacrylate) templates. Thereby nanoparticle clusters with sub‐10‐nanometer interparticle spacing are achieved. Varying the molar concentration of functional chemical groups and crosslinking agent during the assembly process is found to affect the agglomeration of Au nanoparticles into clusters. Samples with a high surface coverage of nanoparticle cluster assemblies yield relative enhancement factors on the order of 109 while simultaneously producing uniform signal enhancements in point‐to‐point measurements across each sample. High enhancement factors are associated with the narrow gap between nanoparticles assembled in clusters in full‐wave electromagnetic simulations. Reusability for small‐molecule detection is also demonstrated. Thus it is shown that the combination of high signal enhancement and reproducibility is achievable using a completely non‐lithographic fabrication process, thereby producing SERS substrates having high performance at low cost.
Deformation Behavior and Damage Evaluation in a New Titanium Diboride (TiB2) Steel‐Based Composite
Authors: Hadjem‐Hamouche Zehoua , Chevalier Jean‐Pierre , Cui Yiting , Bonnet Frédéric
Published: April 2012

Deformation behavior and damage evaluation of a new composite steel has been investigated by means of in situ three‐point bend tests in the scanning electron microscope. The titanium diboride (TiB2)‐reinforced steel composite is produced by in situ precipitation of the TiB2 particles during eutectic solidification. This production process developed by ArcelorMittal leads to a steel composite with a significant increase in specific stiffness (>20%), and good strength/ductility compromise. The microstructures obtained consist of primary TiB2 crystals surrounded by a eutectic mixture of ferrite and TiB2 particles. The primary mode of damage is particle fracture and inhomogeneous plastic deformation in the matrix. In contrast with other production process, particle fracture was more common than interfacial debonding indicating that interfacial strength is not the limiting factor in damage accumulation and fracture in this composite. Crack growth occurred by particle fracture ahead of the crack tip, producing large microvoids, which then link up to the growing crack by ductile failure of the remaining matrix ligaments. The results suggest also that the cracks tended to avoid direct particle interactions.
Deformation Mechanisms and Martensitic Phase Transformation in TRIP‐Steel/Zirconia Honeycombs
Authors: Ehinger David , Krüger Lutz , Martin Ulrich , Weigelt Christian , Aneziris Christos G.
Published: April 2012

The mechanical and structural response of powder metallurgical square‐celled honeycomb structures to quasi‐static and dynamic impact loads are described. By constructing the cellular lattice with a novel metal matrix composite material based on a metastable high‐alloyed austenitic TRIP‐steel particle‐reinforced by magnesia partially stabilized zirconia (Mg‐PSZ), high specific yield and ultimate collapse strengths as well as a high ductility and an enhanced specific energy absorption were gained. In order to prove the temperature sensitivity of the honeycomb structures, a selected low‐reinforced composite condition was investigated in a pre‐series of quasi‐static compression tests at temperatures in the range between −190 and 150°C. The present study shows that the deformation mechanisms of the TRIP‐matrix composite honeycomb structures can be classified with respect to strain rate and deformation temperature, including the failure characteristics and the strain‐induced α′‐martensite transformation in the austenitic steel matrices ensuring the TRIP effect. The evolution of the α′‐martensite phase content in the central crush zone of the TRIP steel and TRIP‐Matrix Composite honeycombs is demonstrated based on the results of magnetic balance measurements.
Fast‐Track Surgery Improves Postoperative Clinical Recovery and Immunity After Elective Surgery for Colorectal Carcinoma: Randomized Controlled Clinical Trial
Authors: Yang Dongjie , He Weiling , Zhang Sheng , Chen Huayun , Zhang Changhua , He Yulong
Published: April 2012

Background

Few clinical studies or randomized clinical trial results have reported the impact of fast‐track surgery on human immunity. This study aimed to investigate the clinical and immune impact of fast‐track surgery in colorectal cancer patients undergoing elective open surgery.

Methods

A controlled randomized clinical trial was conducted from November 2008 to January 2009 with a 1‐month postdischarge follow‐up. A total of 70 patients with colorectal carcinoma requiring colorectal resection were randomized into two groups: a fast‐track group (35 cases) and a conventional care group (35 cases). All included patients underwent elective open colorectal resection with combined tracheal intubation and general anesthesia. Clinical parameters and markers of immune function were evaluated in both groups postoperatively.

Results

In all, 62 patients completed the study: 32 in the fast‐track group and 30 in the conventional care group. Our findings revealed a significantly shorter postoperative hospital stay and faster return of gastrointestinal function in patients undergoing fast‐track rehabilitation. In addition, we found a quicker response of white blood cells in the fast‐track group than in the conventional care group. We also found that blood levels of globulin, immunoglobulin G, and complement 4 on postoperative day 3 were higher in the fast‐track group than in the conventional care group.

Conclusions

Fast‐track surgery accelerates clinical recovery and improves postoperative immunity after elective open surgery for colorectal carcinoma.
Linear elasticity obtained from finite elasticity by $Γ$-convergence under weak coerciveness conditions
Authors: DeSimone Antonio , Agostiniani Virginia , Dal Maso Gianni
Published: April 2012

The energy functional of linear elasticity is obtained as

Γ

-limit of suitable rescalings of the energies of finite elasticity. The quadratic control from below of the energy density

W(\mathrm{∇}v)

for large values of the deformation gradient

∇v

is replaced here by the weaker condition

W(\mathrm{∇}v)⩾|\mathrm{∇}v|^{p}

, for some

p > 1

. Energies of this type are commonly used in the study of a large class of compressible rubber-like materials.
Subjectivism — a reply in defence of classical actuarial methods
Authors: Ryder J. M.
Published: April 2012

The work of science is to substitute facts for appearances and demonstrations for impressions.

1.1 .This paper is an attempt to describe the extent of ‘Subjectivist’ infiltration into theories of actuarial concern, and to present counter arguments defending the objective ‘classical’ actuarial position. The principal entry point for subjectivist ideas has been the ‘latter day rediscovery of the basically statistical nature of actuarial work’ (F. A. Menzler) which has introduced us to Bayesian Statistical Theory and the concept of Insurance Theory as a Theory of Risk. Classical actuarial theory, however, regards this use of Bayesian theory as fallacious, and the Theory of Risk as of relatively minor interest.
Premium loadings for non-participating business
Authors: Pollard J. H.
Published: April 2012

Actuaries tend to use deterministic rather than stochastic methods and confine their calculations to the computation of expectations. The adverse effects of statistical fluctuations are usually avoided by including contingency margins in the calculations and professional judgment plays a large part in the determination of the margins. In this paper, we show how the results of two recent theoretical papers can be used to supplement professional judgment in the area of premium loadings for non-participating business. The methods are also of interest in connection with participating business.
Investment performance of pension funds
Authors: Holbrook J. P.
Published: April 2012

1.1. This paper has its origins in practical work carried out over the last 6 years on behalf of a number of pension funds whose trustees wished to obtain an independent assessment of their investment performance. Annual investigations have been made with two main objectives; first, to compare each fund's performance with that of the other funds under investigation and with investors in general; secondly, to analyse the factors which affected performance in the year and to explain differences between the results obtained by the participating funds. It was hoped that, in addition to providing a historical record, the investigations would reveal strengths and weaknesses in past practice, leading to suggestions for improving performance in the future. As the results for successive years became known it was possible to make statistical analyses over lengthening periods, to reach some tentative conclusions about longer-term performance and to attempt an assessment of the value of investment performance analysis in the practical world where trustees, investment managers and advisers have to operate.
Assessmentism—an alternative to pensions funding?
Authors: Trowbridge J. R.
Published: April 2012

1.1. Occupational pension schemes in Great Britain and in many other countries are experiencing a very difficult period. For several years now actuaries valuing funded pension schemes have been faced all too often with the unenviable task of presenting to their clients the unpopular message that their pension schemes are going to cost more in the future than they did in the past. Furthermore, the increasing pressure to revalue pensions in course of payment and to replace withdrawal benefits by some form of preserved rights is either threatening employers with intolerable funding burdens, or is causing some departure from the established practice of fully funding retirement benefits.
Estimation of the magnitude of accumulated and inherited wealth
Authors: Jones Elfryn
Published: April 2012

1.1. The distribution of personal sector wealth between individuals is far more unequal than the distribution of incomes of individuals. Whereas in 1974 the wealthiest 5% owned 47% of all marketable wealth of the personal sector in this country, the share of the top 5% of incomes was much lower at about 20% of total incomes from all sources (before tax). Life-cycle factors would have contributed to this difference because those nearing retirement have had more opportunity to accumulate savings than those early in their careers. But, as will be seen later, such factors provide only a partial explanation and it has become apparent that the greater inequality in the distribution of wealth is due largely to the incidence of other sources of wealth, such as inheritances. In order to throw more light on the processes which have led to the present distribution of wealth it is necessary to consider models of the build-up of savings out of earnings and, also, methods of estimating the overall size and distribution of inherited wealth. These are the main purposes of this paper.
Some aspects of the London reinsurance market in world-wide short-term business
Authors: Craighead D. H.
Published: April 2012

This paper is partly descriptive, partly analytical, and covers the following aspects:

a description of the market in general;

a brief description of the organization of Lloyd's;

currencies and exchange rates;

calculation of reserves;

taxation;

underwriting; and

accumulation of risk.

§§ 1 and 2 and the earlier paragraphs of § 3 convey information regarding the market that will be well known to actuaries practising in this field and may be passed over without loss. They are added in an attempt to convey a picture of the type of operation that results within an office concentrating on reinsurance business, as against looking at reinsurance in its peripheral effect on a direct writing office.
Matching and portfolio selection: Part 1
Authors: Wise A. J.
Published: April 2012

1.1 My paper entitled ‘The Matching of Assets to Liabilities’ described a new study of the subject of matching. The paper outlined the mathematical framework, showed some calculations, and suggested various applications in the field of actuarial valuation.

1.2 Subsequently A. D. Wilkie published a note entitled ‘Portfolio Selection in the Presence of Fixed Liabilities: a Comment on “The Matching of Assets to Liabilities”’. Wilkie's note appears to represent a new extension of portfolio selection theory which enables him to encompass the conventional portfolio theory and to show where my approach to matching fits into the picture.

1.3 This paper is in the nature of a reply to that of Wilkie. My objective at the stage of the first draft was to re-examine the matching portfolio, as defined in relation to specified liabilities, in view of the wide range of alternative portfolios which Wilkie has described. The scope of this work progressed well beyond my original plans when I found a most interesting mathematical relationship between the ‘matching portfolios’ described in my earlier paper and the ‘efficient portfolios’ described in Wilkie's.
Objectives and methods of funding defined benefit pension schemes
Authors: McLeish D. J. D. , Stewart C. M.
Published: April 2012

The Objective of Funding

1.1. As every actuarial student is taught:

‘Pay-as-you-go is acceptable for a State pension scheme because the State is, for practical purposes, assured of a continuing existence.’

However:

‘The position is quite different in the case of an occupational scheme, since an employer's business may cease to exist.’

1.2. It seems to us to follow, therefore, that the prime purpose of funding an occupational pension scheme must be to secure the accrued benefits, whatever they might be, in the event of the employer being unable or unwilling to continue to pay at some time in the future. To that end, the contributions would have to be sufficient both to pay the benefits as they fell due for as long as the scheme continued, and also to establish and maintain a fund which would be sufficient to secure the accrued benefits in the event of contributions ceasing and the scheme being discontinued, whenever that might occur.
Bias in q and m rate estimates
Authors: Roberts L. A.
Published: April 2012

Bias in estimates of the initial decremental rate q and the central decremental rate m is considered for several survival functions. It is first shown that the central rate estimate is unbiased when the survival function is an exponential curve; is similarly unbiased when the survival function assumes the Balducci shape. The evidence presented here also indicates that the proportional bias (the bias divided by the true value) is approximately twice as great for as for when the survival function is a straight line.

Life tables in common use in the United Kingdom are, however, concave at ages arising most frequently in actuarial calculations, while none of the above curves is concave. In order to investigate the bias properties of general survival functions a quadratic is chosen, with a parameter indicating the extent of curvature. For this particular class of survival functions, one can show that bias is approximately minimized when exposure to risk is symmetric about the middle of the rate year.
Address by the President. Developing a proactive role
Authors: Scurfield Hugh Hedley
Published: April 2012

The Presidential Address visits some of the current issues affecting the actuarial profession and expresses some personal views of the President. Subjects covered include with-profits policies, life assurance withdrawals and disclosure, Europe, education (concerning both actuarial examinations and continuing professional education), general insurance and pensions. The Address demonstrates the need for proactivity in a world which is continually changing, which is the theme of the 2-year presidency.
Strategy for the 1990s. Document prepared by The Planning Joint Committee of the Institute of Actuaries and the Faculty of Actuaries (Chairman, Mr C. D. Daykin) and Approved by Both Councils
Authors: Daykin C. D.
Published: April 2012

The Institute of Actuaries and the Faculty of Actuaries have embarked on a joint planning exercise with a view to developing a more proactive profession, by focusing the attention and energy of members and ensuring effective use of scarce financial and human resources. ‘Strategy for the 1990s’ sets the overall framework of key objectives, which were agreed by a historic joint meeting of the Councils of the Institute and the Faculty on 4 March 1991.
Chain ladder and maximum likelihood
Authors: Verrall R. J.
Published: April 2012

This paper derives second moments of estimates of the parameters in the chain ladder model. Thus, the so-called link ratios, and proportions of ultimate claims for each development year are considered. This enables confidence statements about the chain ladder parameters to be made with statistical rigour. The methods are illustrated using 6 sets of real data taken from the DTI returns.
The recent trend of mortality in Great Britain
Authors: Daykin C. D.
Published: April 2012

This note continues a regular series on mortality rates in Great Britain , showing the mortality experienced in each age-group in 1989 and comparing this for broad age-groups, on a standardised basis, with mortality in earlier years.
Joint modelling for actuarial graduation and duplicate policies
Authors: Renshaw A. E.
Published: April 2012

In this paper it is demonstrated how recently developed statistical techniques designed to facilitate the joint modelling of the mean and dispersion are well suited to model the presence of duplicate policies in graduation.
Report on the Wilkie stochastic investment model
Authors: Geoghegan T. J. , Clarkson R. S. , Feldman K. S. , Green S. J. , Kitts A. , Lavecky J. P. , Ross F. J. M. , Smith W. J. , Toutounchi A.
Published: April 2012

A FIMAG Working Party was set up in 1989 to consider the stochastic investment model proposed by A. D. Wilkie, which had been used by a number of actuaries for various purposes, but had not itself been discussed at the Institute. This is the Report of that Working Party. First, the Wilkie model is described. Then the model is reviewed, and alternative types of model are discussed. Possible applications of the model are considered, and the important question of ‘actuarial judgement’ is introduced. Finally the Report looks at possible future developments. In appendices, Clarkson describes a specific alternative model for inflation, and Wilkie describes some experiments with ARCH models. In further appendices possible applications of stochastic investment models to pension funds, to life assurance and to investment management are discussed.
HIV, AIDS and the approximate calculation of life insurance functions, annuities and net premiums
Authors: Haberman S.
Published: April 2012

The paper presents an application of the Markov chain as a tool for the calculation of life contingencies functions (e.g. assurance, annuity, net premium, policy value functions) arising from a multi-state model which represents the transmission and development of HIV and AIDS. The transmission model advocated by the Institute of Actuaries AIDS Working Party is modified and simplified and then applied to derive explicit formulae for these standard life contingencies functions. This investigation allows a thorough review of the properties of these functions to be conducted and assists with the calculation of premiums and reserves in the presence of HIV and AIDS.
Statistical motor rating: making effective use of your data
Authors: Brockman M. J. , Wright T. S.
Published: April 2012

The paper gives details of statistical modelling techniques which can be used to estimate risk and office premiums from past claims data. The methods described allow premiums to be estimated for any combinaton of rating factors, and produce standard errors of the risk premium. The statistical package GLIM is used for analysing claims experience, and GLIM terminology is used and explained thoughout the paper.

Arguments are put forward for modelling frequency and severity separately for different claim types. Pitted values can be used to estimate risk premiums, and the incorporation of expenses allows for the estimation of office premiums. Particular attention is given to the treatment of no claim discount.

The paper also discusses possible uses of the modelled premiums. These include the construction of ‘standardised’ one way tables and the analysis of experience by postal code and model of vehicle. Also discussed is the possibility of using the results for assessing the impact of competition, and for finding ‘niche’ markets in which an insurer can operate both competitively and profitably.
Reserving for catastrophe reinsurance
Authors: Craighead D. H.
Published: April 2012

The paper sets out the method required to be followed when estimating reserves for a Company or a Lloyd's Syndicate which has accepted reinsurance treaties that have given rise to catastrophe losses, sufficiently large to upset the normal development pattern and to affect the gross account quite differently from the net account. The losses may be caused by single factors such as aircraft crashes or oil rig disasters, or by the aggregation of claims resulting from a windstorm or an earthquake. The paper discusses two possible approaches to estimation of the gross losses; via exposure totals or via statistical modelling techniques.
Defining and protecting the pension promise
Authors: Goode Roy
Published: April 2012

The 1993 Jubilee Lecture considered two fundamental questions addressed in the report of the Pension Law Review Committee: when an employee joins an occupational pension scheme, what should the law consider to be the fundamental pension promise; and how should that promise be protected? The factors affecting the employee's expectations are examined in the light of the pension promise, and the conclusion drawn that certain expectations relating to accrued rights should be protected by law, although the employer should be able to control its financial commitments as to future service. The status of surplus, in both an ongoing scheme and in the event of a wind-up, is also considered, and recommendations made as to the use of a surplus if not already dealt with by the scheme rules. The two principal forms of protection for the pension promise which were recommended by the Pension Law Review Committee are discussed; firstly, the introduction of a minimum solvency standard, backed up by tighter rules for the prompt payment of contributions and by enhanced monitoring and reporting requirements for scheme auditors and actuaries; and secondly, the setting up of a statutory compensation fund to cover a deficit in the event of fraud or theft, to be financed by a post-event levy on schemes.
Notes on the FT–SE Actuaries Share Indices (United Kingdom Series) in 1993
Authors: Brumwell J. C. H.
Published: April 2012

Introduction of the new Total Return Indices. New Industrial Classification system introduced at the beginning of 1994, integrating the previously separate FT–Actuaries Share Indices and (more detailed) Stock Exchange groupings.