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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2007.09.001 Byline: P.K. Tewari, V.S. Batra, M. Balakrishnan Abstract: Agro-based pulp and paper mills in India are one of the most polluting industries; in addition, they are high consumers of raw water. Growing scarcity of high quality freshwater as well as stringent regulatory standards is compelling these units to explore appropriate water management options. Based on data obtained through a questionnaire survey and plant visits, this work provides an overview of the water use and effluent treatment status in Indian agro-residue and recycled pulp and paper mills. The challenges faced by this sector are reviewed and practices adopted by progressive units to minimize freshwater use are illustrated through case studies. Author Affiliation: The Energy and Resources Institute (TERI), Darbari Seth Block, India Habitat Center, Lodhi Road, New Delhi 110003, India Article History: Received 20 March 2007; Revised 18 August 2007; Accepted 15 September 2007

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.forsciint.2009.07.004 Byline: Charles E.H. Berger Keywords: Forensic science; Paper structure; Comparison; Feature vector; FFT; Correlation Abstract: A method for the comparison of paper structure using light transmission images and frequency analysis was developed. The resolution of the light transmission images and the algorithm for the feature extraction were greatly improved to enhance the visibility of peaks in the 2D power spectrum that results from frequency analysis. A comparison method based on correlation measures how well the spectra match as a function of the orientation of the paper, yielding an objective and quantitative measure of similarity between 0 and 1. A technical validation was carried out with 25 different papers showing the potential of this method with common copy papers. Finally, the method was applied in a case. Author Affiliation: Netherlands Forensic Institute, Laan van Ypenburg 6, P.O. Box 24044, 2490 AA The Hague, The Netherlands Article History: Received 22 March 2009; Revised 27 June 2009; Accepted 1 July 2009

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.apergo.2009.01.003 Byline: Yu-Ting Lin (a), Po-Hung Lin (a), Sheue-Ling Hwang (a), Shie-Chang Jeng (b), Chi-Chang Liao (b) Abstract: This study employs simulated electronic paper to investigate critical issues and focuses on improving legibility of display and reducing users' visual fatigue. Three critical factors - choice of surface treatment, ambient illumination, and bending curvature - are evaluated through the method of a letter-search task. The results show that subjects performed better on legibility and felt less visual fatigue with an anti-glare treatment. Choosing the better anti-glare treatment instead of the anti-reflection series can save significant cost for manufacturers. In addition, ambient lighting of 1500lux is more appropriate for reading on electronic paper than an environment with extreme illumination (e.g., 8000lux). The present study also found that curvature had no impact on legibility or visual fatigue. These evaluations of simulated electronic paper may provide manufacturers useful information in fulfilling ergonomic requirements for product design. Author Affiliation: (a) Department of Industrial Engineering and Engineering Management, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu, Taiwan (b) Electronics and Optoelectronics Research Laboratories, Industrial Technology Research Institute, 195, Section 4, Chung-Hsing Road, Chutung, Hsinchu, Taiwan Article History: Received 21 May 2007; Accepted 7 January 2009

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2004.08.004 Byline: Kerry L. Bridle, J.B. Kirkpatrick Abstract: An examination of the relative breakdown rates of unused toilet paper, facial tissues and tampons was undertaken in nine different environments typical of Tasmanian natural areas. Bags of the paper products (toilet paper, facial tissues, tampons) were buried for periods of 6, 12 and 24 months at depths of 5 and 15cm. A nutrient solution simulating human body wastes was added to half of the samples, to test the hypothesis that the addition of nutrients would enhance the breakdown of paper products buried in the soil. Mean annual rainfall was the most important measured variable determining mean breakdown in the nutrient addition treatment between sites, with high rainfall sites (mean annual rainfall of greater than 650mm) recording less decayed products than the drier sites (mean annual rainfall of 500-650mm). Temperature and soil organic content were important influences on the breakdown of the unfertilised products. Toilet paper and tissues decayed more readily than tampons. Nutrient addition enhanced decay for all products across all sites. Depth of burial was not important in determining the degree to which products decayed. In alpine environments, burial under rocks at the surface did not increase the speed of decay of any product. The Western Alpine site, typical of alpine sites in the Tasmanian Wilderness World Heritage Area, showed very little decay over the two-year period, even for nutrient enhanced products. Management prescriptions should be amended to dissuade people from depositing human toilet waste in the extreme (montane to alpine) environments in western Tasmania. Tampons should continue to be carried out as currently prescribed. Author Affiliation: School of Geography and Environmental Studies, University of Tasmania, Private Bag 78, Hobart 7001, Tasmania, Australia Article History: Received 8 August 2003; Revised 21 June 2004; Accepted 25 August 2004

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ejor.2007.10.019 Byline: Kazuki Matsumoto (a), Hiroyoshi Miwa (b), Toshihide Ibaraki (b) Keywords: Scheduling; Corrugated paper; Complexity; Contiguous set; Integer programming Abstract: Corrugated paper is produced by gluing three types of papers of the same breadth. Given a set of orders, we first assign each order to one of the standard breadths, and then sequence those assigned to each standard breadth so that they are continuously manufactured from the three rolls of the specified standard breadth equipped in the machine called corrugator. Here we are asked to achieve multi-goals of minimizing total length of roll papers, total loss of papers caused by the differences between standard breadths and real breadths of the orders, and the number of machine stops needed during production. We use integer programming to assign orders to standard breadths, and then develop a special purpose algorithm to sequence the orders assigned to each standard breadth. This is a first attempt to handle scheduling problems of the corrugator machine. Author Affiliation: (a) Department of Applied Mathematics and Physics, Graduate School of Informatics, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan (b) Department of Informatics, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen Sanda, Hyogo 669-1337, Japan Article History: Received 24 March 2007; Accepted 5 October 2007

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2007.09.007 Byline: Arun K. Srinivasan (a), Glenn C. Blomquist (b) Abstract: Ecolabeled paper towels are manufactured using post-consumer recycled material and sold in markets using a recycle logo. Environmentally conscious consumers purchase these paper towels and thereby contribute to improving environmental quality. In this paper, we estimate the implicit value placed by consumers on ecolabeled paper towels using a hedonic price function and conduct an expenditure analysis using Heckman's selection model. Using the data set from the Internet-based grocery stores called as Peapod we find that some consumers recognize ecolabels on paper towels and place a substantial, positive price premium on them. The expenditure analysis indicates that for the preferred functional form, the demand for ecolabeled paper towels is inelastic for environmentally conscious consumers. The simulated results from the selection model indicate that a small subsidy for ecolabeled paper towels will not substantially change consumers' purchase decisions. Author Affiliation: (a) School of Business, Indiana University Southeast, 4201 Grant Line Road, HH 216M, New Albany, IN 47150, USA (b) Department of Economics, University of Kentucky, Gatton College of Business and Economics 335Q, Lexington, KY 40506-0034, USA Article History: Received 26 September 2006; Revised 6 July 2007; Accepted 29 September 2007

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2007.01.007 Byline: M. UAurlu (a), A. Gurses (b), A. DoAar (c), M. Yalcin (d) Keywords: Paper mill effluents; Electrocoagulation; Phenol; Lignin; BOD; COD Abstract: This study aims to investigate the treatment of paper mill effluents using electrocoagulation. Removal of lignin, phenol, chemical oxygen demand (COD) and biological oxygen demand (BOD) from paper mill effluents was investigated at various current intensities by using different electrodes (Al and Fe) and at various electrolysis times (1.0, 2.5, 5.0 and 7.5min). It was observed that the experiments carried out at 12V, an electrolysis time of 2min and a current intensity of 77.13mA were sufficient for the removal of these pollutants with each electrode. The removal capacities of the process using an Al electrode were 80% of lignin, 98% of phenol, 70% of BOD, and 75% of COD after 7.5min. Using an Fe electrode the removal capacities were 92%, 93%, 80% and 55%, respectively. In addition, it was found that removal of lignin, phenol, BOD and COD increased with increasing current intensity. In the experiments carried out at different current intensities, higher removal can be explained through a decrease in intra-resistance of solution and consequently an increase at the transfer speed of organic species to electrodes. It was also found that Al electrode performs higher efficiency than Fe electrode except for COD removal. However, the time required for removal of BOD was more than that of COD. The results suggest that electrocoagulation could be considered as an effective alternative to paper mill effluents treatment. Author Affiliation: (a) Department of Chemistry, Faculty of Science and Literacy, MuAla University. 48000 MuAla, Turkey (b) Department of Chemistry, K.K. Education Faculty, Ataturk University, 25240 Erzurum, Turkey (c) Department of Science Education, Erzincan Education Faculty, Ataturk University, 24030 Erzincan, Turkey (d) Department of Science Education, Bayburt Education Faculty, Ataturk University, 24030 Bayburt, Turkey Article History: Received 29 July 2005; Revised 15 January 2007; Accepted 20 January 2007

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jeem.2006.10.004 Byline: Philippe Barla Keywords: Environmental management systems; ISO 14001; Environmental performance Abstract: This paper tests whether adopting the international norm ISO 14001 significantly impacts environmental performance in Quebec's pulp and paper industry. Using monthly data collected from 37 plants between 1997 and 2003, we show that: (i) ISO certification does not lead to a reduction in total suspended solid emissions or in quantity of rejected process water; (ii) discharge of biological oxygen demand decreases by about 9% following certification; (iii) contrary to the group of plants that did not adopt the ISO norm, the adopting plants did not experience a significant negative trend in emissions over our sample period. Moreover, our results show that the impact of ISO is very variable across adopting plants. If some plants considerably reduce emissions following certification, we find that most adopters either maintain or even increase emissions after being ISO accredited. Author Affiliation: GREEN and Departement d'economique, Universite Laval, Que., Canada G1K 7P4 Article History: Received 20 July 2005

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2005.09.014 Byline: Vinay Kumar Jha (a), Yoshikazu Kameshima (a), Akira Nakajima (a), Kiyoshi Okada (a), Kenneth J.D. MacKenzie (b) Keywords: Waste paper sludge; Mechanochemical treatment; Ni.sup.2+ uptake; Amorphous CaO-Al.sub.2O.sub.3-SiO.sub.2 Abstract: Uptake properties of Ni.sup.2+ were examined for unmilled and milled paper sludge calcined at various temperatures to develop a new usage of waste paper sludge. Since paper sludge mainly consists of cellulose ([C.sub.6H.sub.10O.sub.5].sub.n) fibers, calcite (CaCO.sub.3), kaolinite (Al.sub.2Si2O.sub.5(OH).sub.4) and talc (Mg.sub.3Si.sub.4O.sub.10(OH).sub.2), amorphous and crystalline CaO(MgO)-Al.sub.2O.sub.3-SiO.sub.2 compounds are formed by calcining paper sludge. Wet and dry milling treatments were performed to accelerate solid-state reaction to form the above mentioned target compounds. The crystalline phases originally present decompose at increasing calcining temperature (up to 800[degrees]C) in the order cellulose Author Affiliation: (a) Department of Metallurgy and Ceramics Science, Tokyo institute of Technology, O-okayama, Meguro, Tokyo 152-8552, Japan (b) School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand Article History: Received 30 June 2004; Revised 24 August 2005; Accepted 30 September 2005

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ejor.2007.08.033 Byline: Philip C. Jones, Jeffrey W. Ohlmann Keywords: OR in agriculture; Forest economics; Normal forest; Regulated forest; Newsvendor model; Forestry supply chain management Abstract: We consider a vertically integrated papermaking operation composed of an integrated pulp and paper mill with its regional supply network. Considering land procurement and harvest rotation as strategic decision variables, we construct a model to establish a long-range timber supply plan that minimizes the total discounted cost of meeting annual virgin wood fiber demand over an infinite horizon. Under appropriate assumptions on costs and storage, the land procurement and harvest rotation decisions are separable with harvest rotation being determined via a forest economics-type equation and land procurement being determined by a newsvendor-type equation. Author Affiliation: Department of Management Sciences, 108 John Pappajohn Business Building, University of Iowa, Iowa City, IA 52242-1994, United States Article History: Received 18 January 2006; Accepted 24 August 2007

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2004.11.021 Byline: Marcus Wagner Abstract: This paper discusses the relationship between environmental and economic performance and the influence of corporate strategies with regard to sustainability and the environment. After formulating a theoretical model, results are reported from an empirical analysis of the European paper manufacturing industry. New data are used to test hypotheses derived from the theoretical model, using environmental performance indices representing different corporate environmental strategy orientations. In particular, an emissions-based index largely reflecting end-of-pipe strategies and an inputs-based index reflecting integrated pollution prevention are distinguished. For the emissions-based index, a predominantly negative relationship between environmental and economic performance is found, whereas for the inputs-based index no significant link is found. This is consistent with the theoretical model, which predicts the possibility of different relationships. The results also show that for firms with pollution prevention-oriented corporate environmental strategies, the relationship between environmental and economic performance is more positive, thus making improvements in corporate sustainability more likely. Based on this last insight, managerial implications of this are discussed with regard to strategy choices, investment decisions and operations management. Author Affiliation: Center for Sustainability Management, University of Luneburg, Scharnhorststrasse 1, 21335 Luneburg, Germany Article History: Received 7 March 2004; Revised 28 October 2004; Accepted 4 November 2004

The market expectations hypothesis related to term premia for commercial papers issued by United States corporations is analyzed.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2006.10.020 Byline: I. Akmehmet BalcioAlu (a), E. Tarlan (b), C. Kivilcimdan (c), M. Turker Sacan (a) Keywords: Algal treatment; Catalytic ozonation; CEH bleaching; Integrated treatment; Kraft pulp; Toxicity Abstract: Since the performance of algal treatment for pulp mill effluent decreases with increasing color intensity and AOX content, which mainly originate from the chlorine bleaching of Kraft pulp, the separated CEH bleaching effluent was pre-treated by both the conventional and the heterogeneous catalytic ozonation processes. An increase in the BOD.sub.5/COD ratio from 0.11 to 0.28 and 87% color abatement in terms of Pt-Co were achieved by catalytic ozonation, which had the best treatment performance. Biodegradability enhancement of the CEH effluent correlated well with a decrease in toxicity, high-molecular-weight-compound content, and AOX abatement. By the pre-treatment of the CEH bleaching effluent, the overall efficiencies of algal treatment of the combined pulp mill effluent in terms of the fractional removal of COD and color were increased from 76% and 53% to 86-90% and 96-99%, respectively. Effects of both the conventional and the catalytic ozonation pre-treatments on subsequent biological treatment were close to each other and they reduced the filling period of the Sequential Batch Reactor (SBR) cycle from 8 to 5 days. Author Affiliation: (a) BoAazici University, Institute of Environmental Sciences, 34342 Bebek-Istanbul, Turkey (b) Faculty of Engineering and Architecture, Department of Environmental Engineering, Selcuk University, 42075 Kampus-Konya, Turkey (c) Department of Environmental Engineering, Middle East Technical University, 06531 Ankara, Turkey Article History: Received 21 March 2006; Revised 19 October 2006; Accepted 31 October 2006

The authors use an analytic hierarchy procedure to create priority indices for paper recycling within the manufacturing industry. The procedure incorporates cost-effective design, customer requirements and a systemic framework.

Research describing recognition pheromones in the social wasp, Polistes dominulus, is presented. In particular the behavior of nestmates after the application of different hydrocarbons to a returning wasp is investigated.

The potential of the paper-bill spread to foresee business cycle changes dwindled in the 1980s as liquidity of commercial paper increased. The latter incited investors to consider paper as an approximate alternative for Treasury bills. Consequently, shocks to the paper and bill markets did not significantly affect the paper-bill spread but were actually incorporated by proportional yield alterations in both markets. This findings veer away from explanations that attribute the predictive decline to market contractions and to changes in paper and bill supplies unrelated to business conditions.

A small cross-sectional study of upper extremity disorders was conducted in two departments of a pulp and paper mill. The objective of the study was to determine the prevalence of upper extremity disorders and identify any associated work place risk factors in long cycle jobs with multiple tasks of varying duration. Physical exams and health status interviews were conducted on 23 employees (77%) in the paper machine department and on 17 employees (59%) of the power and recovery department. All participants completed questionnaires on physical and psychosocial job characteristics. There was a statistically significant difference in hand and wrist disorders between the two departments at the p < 0.05 level (34.8% in the power and recovery department, and 5.9% in the paper machine area). Multiple logistic regression models showed a significant relationship between the use of a steel lance and shoulder disorders. Elbow arthritis was also associated with lance usage. There was evidence that the job analysis was not able to fully describe the risk factors present in the paper machine department. Biomechanical exposures existing prior to the time of the study may not have been adequately characterized. An important aspect of this study is that the jobs studied were not typical repetitive jobs that are commonly studied. Keywords: carpal tunnel syndrome, tendinitis, cumulative trauma disorder, pulp and paper, process industry

The tolerance and aggression between nestmates and non-nestmates were studied in the paper wasp, Polistes dominulus, to determine whether nestmate discrimination is context-dependent. Three contexts were considered, namely dyads composed of a pair of non-nestmates, dyads composed of a pair of nestmates and triads composed of two nestmates and a non-nestmate. The findings showed that P. dominulus workers are capable of distinguishing between neighbors from non-neighbors, familiar from unfamiliar fragments and nestmates from non-nestmates.

The Ming dynasty (1368-1644) abandoned the paper money system established by the Sung dynasty (960-1279) due to inflation problems caused by over-issuance. It was driven to do so by competition from metallic currencies which raised 'interest elasticity of paper money demand.' This is proven using the Cagan adaptive expectations model and the money-in-utility model. Likewise, the Southern Sung government's dependence on a leaning-with-the-wind feedback approach to prevent self-generating inflation is discussed.

The effect of inspections on the self-reported quality emission levels of pulp and paper facilities in Quebec was studied in a basic model which considered the discharges of biological oxygen demand and total suspended solids. It was recognized that both the Canadian and US governments have inadequate resources to monitor and implement environmental regulations. It was concluded that inspections and the probability of inspections have a significant negative effect on emissions. In addition, regulators are given more information due to more frequent reporting.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.chb.2008.05.012 Byline: Mary J. Naus, Laura M. Philipp, Mekhala Samsi Keywords: Paper and computer formats in psychological assessment; Computers in psychological research; Quality of life; Depression; Personality Abstract: Internet based data collection methods have many advantages for psychological assessment when compared with more traditional paper formats, including, reduced costs, and greater convenience for both the researcher and the participant. However, prior to the wide-spread adoption of these methods, equivalence with paper tests formats must be established. The present study compared questionnaire data from the computer with that from a traditional paper format in a sample of college students both directly and through an opinion survey. Three types of questionnaires that represent distinct areas commonly assessed in psychological research included: quality of life (SF-36), depression (BDI-II) and personality (NEO). A within-subjects design counterbalanced order across the computer and paper formats. Overall the findings showed no differences for the Neuroticism and Extraversion facts of the NEO, for the BDI and for the subscales and composite scores of the SF-36. Significant differences were found between the paper and computer formats for the Openness, Agreeableness, and Conscientiousness facets of the NEO. Additionally, the computer was perceived to be convenient, user-friendly, comfortable, and secure. Results suggest that a computerized format is an efficient way to conduct quality of life research, especially for the assessment of distress levels and quality of life. Author Affiliation: Health Psychology Research Group, Department of Psychology, University of Houston, 126 Heyne Building, Houston, TX 77204-5022, United States

A container loading software package for solving the different problems involved in the containerization of pulp and paper products is presented. The software boasts of a packing algorithm for creating a two-dimensional pattern for placing reels on the floor of container, a heuristic algorithm for two-dimensional stowing of reels of a common diameter and a second packing algorithm for stowing pallets of various sizes. Its applicability has been validated in several decision situations which include the determination of feasible reel diameters and efficient stowage patterns.

Data indicate the unreliability of information from the spread for industrial production growth in predicting economic activity contrary to what Benjamin M. Friedman and Kenneth N. Kuttner postulated in a series of articles since 1989. Two outliers in the data indicate the predictive content of the spread, namely, the 1974 Franklin National Bank episode and the imposition of the Carter Credit controls in 1980.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jebo.2009.03.019 Byline: Ghislaine Lydon Keywords: Institutions; Islamic law; Literacy; Early modern trade; Religion and economics Abstract: This article contributes to the literature on Islamic institutional history by examining how the discounting of documents in Islamic legal practice constrained the organization of early modern Muslim trade. It is argued that the reliance on literacy, on the one hand, and an Islamic legal framework, on the other, gave early modern Muslim traders a comparative advantage in economic organization, but the lack of faith in paper as documentary evidence in Islamic law posed fundamental constraints to the development of Muslim economies. Author Affiliation: Department of History, University of California, 6265 Bunche Hall, Los Angeles, CA 90292, USA Article History: Received 17 November 2007; Revised 23 March 2009; Accepted 23 March 2009

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2010.07.003 Byline: I. Ortolani (a), L. Zechini (a), S. Turillazzi (a)(b), R. Cervo (a) Abstract: Obligate social parasite insects are specialized in exploiting the parental service of the workers of another social species by invading their colonies. As social insects are usually aggressive towards intruders, social parasites have to circumvent the host's nestmate recognition system to enter the host colony successfully. Many studies on paper wasps have shown that, after host nest invasion, Polistes social parasites change their chemical profile to match the host's odour, thus allowing their acceptance into its colony. However, a social parasite's usurpation strategy may benefit from signals that reduce or eliminate the aggression of the host. We used lure presentation experiments to investigate whether Polistes sulcifer, a social parasite of the paper wasp P. dominulus, is able to reduce the aggressive reaction of its host. We found that the parasite lure elicited lower host aggressiveness than the conspecific lure, suggesting that parasite species have evolved cues able to inhibit host aggressiveness. We investigated separately the effects of chemical and visual patterns on host aggressiveness. The lower host reaction to the parasite lure was not due to chemical cues, but was elicited by the visual facial pattern of the parasite. Experimental manipulation of this visual pattern demonstrated that the black lower part of the clypeus of the parasite is the trait able to reduce host aggression. This pattern can be considered an honest signal since it visually amplifies the mandibular width, giving information about the parasite's dangerousness. Author Affiliation: (a) Department of Evolutionary Biology, University of Florence, Italy (b) Interdepartmental Centre of Mass Spectrometry, University of Florence, Italy Article History: Received 7 March 2010; Revised 31 March 2010; Accepted 5 July 2010 Article Note: (miscellaneous) MS. number: 10-00162R

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.forsciint.2009.12.056 Byline: Valerio Causin (a), Carla Marega (a), Antonio Marigo (a), Rosario Casamassima (b), Giuseppe Peluso (b), Luigi Ripani (b) Keywords: Forensic science; Questioned documents; Paper; Cellulose; Polymers; IR spectroscopy; X-ray diffraction Abstract: The possibility to discriminate between sheets of paper can be of considerable importance in questioned document examinations. 19 similar types of office paper were characterized by infrared spectroscopy and X-ray diffraction to individuate the most discriminating features that could be measured by these techniques. The discriminating value associated to them was also assessed. By using a sequence of these two techniques, all the samples could be differentiated. Author Affiliation: (a) Dipartimento di Scienze Chimiche dell'Universita, via Marzolo 1, 35131 Padova, Italy (b) Sezione di Chimica, Esplosivi ed Infiammabili, Reparto Carabinieri Investigazioni Scientifiche, Viale Tor di Quinto 151, 00191 Roma, Italy Article History: Received 10 July 2009; Revised 16 December 2009; Accepted 17 December 2009