bluuebunny/crossref_metadata_2025 huggingface dataset:
Implementing IAS-IFRS in the Moroccan Context: An Explanatory Model
Authors: Ahsina Khalifa
Published: October 2012

The International Financial Reporting Standards (IFRS) have been the subject of several research papers, however, this type of work is still absent in Morocco, hence the importance of this research. This article aims to propose an explanatory model of variables influencing the implementation of IAS- IFRS in the Moroccan context. Based on the contingency theory, we tested the relationship between the adoption of these standards and contingency factors. The analysis of empirical data allows us to observe the influence of these variables on the adoption of international accounting standards.
The board of directors and the corporate tax planning: Empirical Evidence from Tunisia
Authors: Khaoula Aliani , Ali Zarai Mohamed
Published: October 2012

Our study represents the first attempt to investigate whether board of directors’ attributes have an impact on corporate tax planning in a developing country. Using a sample of 32 companies listed on the Tunisian stock exchange market from 2000 to 2007, results indicate that duality and diversity on the board of directors significantly influences tax planning. Duality exhibits a negative relation with effective tax rates. However, diversity on the board shows a positive association. We don’t find relations between board size, independent directors and corporate tax planning. We contribute to the large literature on corporate tax planning by proposing that board’s characteristics may have a substantial effect on reducing effective tax rates. We add a new angle to existing studies on corporate tax governance by involving board’s diversity and sectorial effect. An implication of this study is that tax planning would be decreased by women’s presence on the board of directors. In addition, tax incentives granted by the state to some sectors may improve tax strategies.
Crash occurrence probability and stock market efficiency the indie stock exchange case via Shannon entropy
Authors: Adel Boubaker , Lamia Sahli
Published: October 2012

In this study, we evaluate the relationship between efficiency and probability of the crash, thus the evolution of the daily informational efficiency is measured for the indie stock market index. The efficiency, which is the issue addressed by the weak-form efficient market hypothesis, is calculated using a new method the Shannon entropy and the symbolic time series analysis. A logit model is applied in order to study the relationship between efficiency and probability of the financial crash.
Value relevance of accounting data and financial crisis in Europe: an empirical analysis
Authors: Devalle Alain
Published: October 2012

This paper aims at verifying the relationship between book value and  market value for a four years period (2006-2009) in Europe, under IFRS. In particular, I used value relevance approach to measure whether net income or comprehensive income are more useful to understand the relationship between market data and financial data. Moreover, the paper analyzes the impact of financial crisis on the value relevance of accounting data. The examination period runs from a pre-crisis period (2006-2007) to an in-crisis period (2008-2009). Results shows that comprehensive income is more value relevant than net income. Furthermore, the financial crisis has a positive impact on value relevance.
Auditing Government Institutions in Zimbabwe Frameworks, Processes and Practices
Authors: Gideon Zhou , Tawanda Zinyama
Published: October 2012

Public Audit Offices are the guardian of the national purse and the pivot of the system of parliamentary control over finance. They help to institutionalize and nurture a culture of accountability, integrity, legitimacy and value for money in the conduct of public business. This in the long term serves as antidotes against institutional corruption. Study findings indicate that Zimbabwe’s audit systems are in the main consistent with regional and global experiences. Efforts are being undertaken to reconstitute and strengthen legal frameworks governing public auditing. Notwithstanding this, legal frameworks did not go deep enough to strengthen the independence of supreme audit institutions. Appointment, funding and reporting frameworks still have peeling effects on the operational independence of the Comptroller and Auditor General. Scenarios aground also suggest that the political will to comply with extant frameworks is low note. Audit recommendations are not seriously taken by Treasury, Accounting Officers and government ministers. There is need to update legal and regulatory frameworks to strengthen the operational independence of the C&AG and also to give it sanction powers to compel Ministries and departments to observe and comply with the Treasury Instructions and other regulations regarding submissions of returns. Efforts should also be directed towards capacitating the C&AG in term of attracting and retaining skilled and experienced staff in the legal and accounting field.
Evaluation of Bacterial Adhesion on Machined Titanium, Osseotite® and Nanotite® Discs
Authors: Baena Ruggero Rodriguez Y , Arciola Carla Renata , Selan Laura , Battaglia Rosalia , Imbriani Marcello , Rizzo Silvana , Visai Livia
Published: October 2012

Purpose

Bacterial adhesion and colonization play a crucial function in the pathogenesis of peri-implant tissue infection, which is considered the main cause of fixture loss. The aim of this study is to evaluate the differences in bacterial adhesion between a machined titanium surface, a double acid etched surface (Osseotite®) and an Osseotite surface with Nanometer-scale Discrete Crystalline Deposition (DCD™) of calcium phosphate (CaP)(Nanotite®).

Methods

Surface roughness properties of each sample were determined by a laser profilometer and scanning electron microscopy (SEM) observation. Bacterial adhesion on machined, Osseotite®, and Nanotite® discs were performed using the following bacterial strains: Streptococcus mutans CCUG 35176, Streptococcus sanguis CCUG 17826, Streptococcus salivarius CCUG 11878, Actinobacillus actinomycetecomitans CCUG 37002, Porphyromonas gingivalis CCUG 2521. The assessment of bacterial adhesion was performed by comparing two methods: Total Viable Count (TVC) estimation and Confocal Laser Scanning Microscopic (CSLM) studies.

Results

The surface roughness parameter increased as follows: machined<Nanotite®<Osseotite®. The attachment of all bacterial strains performed by both methods showed a significant reduction on Osseotite® and even higher on Nanotite® in comparison to machined surfaces (p<0.05). The reduction in bacterial attachment was more significant on Osseotite® and Nanotite® for A. actinomycetecomitans, S. mutans and S. sanguis than for P. gingivalis and S. salivarius strains.

Conclusions

Nanotite® samples showed the lowest amount of bacterial contamination in comparison to the smoother machined and rougher Osseotite® surfaces.
An Exploration of the Relational Effects of Supply Chain Disruptions
Authors: Porterfield Tobin E. , Macdonald John R. , Griffis Stanley E.
Published: October 2012

Recent catastrophic events have disrupted supply chains around the globe, causing practitioners and academics to look more closely at recovery strategies. Recent examinations of supply chain disruptions focus primarily upon the recovery process and its impacts on firm performance. However, less is known about how supply chain disruptions affect business‐to‐business (B2B) relationships. This study uses interview data from senior supply chain managers to explore how a firm's disruption recovery processes affect supply chain relationships. Results suggest that firms desire supply chain partner participation in the recovery process and value interpersonal characteristics, including honesty, accessibility, and responsiveness.
Impact of Collaborative Transportation Management on Logistics Capability and Competitive Advantage for the Carrier
Authors: Wen Yuh‐Horng
Published: October 2012

Collaborative transportation management (CTM) is a relatively new collaboration model that addresses inefficiencies in the transportation process in supply chains. This study empirically examines the impacts of CTM on logistics capability and competitive advantage of carriers within a supply chain, and analyzes the relationships between logistics capability and competitive advantage. Based on factor analysis, key factors of CTM practice, key logistics capabilities, and key competitive advantage factors for carriers are identified. The relationships proposed in the framework are tested using structural equation modeling. Analytical results demonstrate that CTM practice enhances logistics capability and competitive advantage, with logistics capability reinforcing competitive advantage. In other words, CTM can have a direct and positive influence on competitive advantage, and an indirect influence through logistics capability. The results also indicate that carriers establish higher levels of integrated relationship with their customers in a CTM model can lead to improved customer‐service capability and enhanced cost‐leadership advantage.
Proposed Modifications to the Cost‐Benefit Analysis Decision Criteria for Road Project Evaluation to Improve Decisionmaking
Authors: Davies Wayne
Published: October 2012

The Australian Transport Council (ATC) have identified that the benefit cost ratio (BCR), the net present value (NPV), and first‐year rate of return (FYRR) decision criteria are appropriate inputs to project prioritization, mutual exclusive project selection, and optimal timing, respectively. This article suggests the net benefit investment ratio (NBIR), the incremental net benefit investment ratio (INBIR), and the internal rate of return (IRR) subject to decision criteria incorporating the marginal project as alternatives to those proposed by the ATC. The proposed decision criteria aim to reduce the impact of uncertainty surrounding discount rates and opportunity costs of capital, hence improving the quality of the quantitative inputs provided to decisionmakers.
SOM-Based Approach for the Analysis and Classification of Synchronous Impulsive Noise of an In-Ship PLC System
Authors: Acciani G. , Amoruso V. , Fornarelli G. , Giaquinto A.
Published: October 2012

The interest in wideband data transmission over power line communications has increased rapidly. This technology offers a convenient and inexpensive medium to transmit data, reducing the number of cables. This advantage is particularly appealing in many fields, like the railway, naval, and aeronautical ones. Nevertheless, several problems have to be faced to obtain a high data rate. In particular, the presence of noise makes the transmission difficult, degrading the quality of received signals and prohibiting the full application of these communication frameworks. In this paper the behaviour of an in-ship powerline communication system is analyzed in the presence of synchronous periodic impulsive noise. Such noise is modelled at source and its effects on the transmission of wideband signals are evaluated by means of a simulation circuit model. The obtained results allow to identify the characteristics of the channel and the critical conditions due to noise. Subsequently, an unsupervised technique based on principal component analysis and fuzzy c-mean classifier detects the presence and classifies the specific noises. Numerical results show that the proposed approach enables to achieve this target accurately under different operating conditions, proving to be an effective tool to enhance the performances of the considered technology.
Studies on Nanocomposites of Polyaniline and Zinc Oxide Nanoparticles with Supporting Matrix of Polycarbonate
Authors: Ansari Shahid Pervez , Mohammad Faiz
Published: October 2012

Nanocomposites of polyaniline and zinc oxide nanoparticles using polycarbonate as supporting matrix were prepared by direct mixing process. These nanocomposites were studied for their DC electrical conductivity using four-in-line probe technique. Stability of DC electrical conductivity in terms of electrical conductivity retention was also studied using two slightly different techniques. The nanocomposites were also characterized using FTIR, SEM, TEM, and XRD. It was found that the electrical conductivity of the nanocomposites first increased with the increase in concentration of ZnO nanoparticles content, but then decreased on further increase in its content. Stability studies showed that the loss in electrical conductivity decreased with increase of ZnO content in nanocomposites. TEM and XRD results showed that nanoparticles are uniformly distributed in polymer matrix and also suggest that the direct solution mixing method may be adopted as an easy and efficient route for the preparation of nanocomposites.
Growth and Physiological Responses of Maize and Sorghum Genotypes to Salt Stress
Authors: Niu Genhua , Xu Wenwei , Rodriguez Denise , Sun Youping
Published: October 2012

The growth and physiological responses of four maize inbred lines (CUBA1, B73, B5C2, and BR1) and four sorghum hybrids (SS304, NK7829, Sordan 79, and KS585) to salinity were determined. Fifteen days after sowing, seedlings were irrigated with nutrient solution (control) at electrical conductivity (EC) of 1.5 dS m−1or saline solution at EC of 8.0 dS m−1(salt treatment) for 40 days. Dry weight of shoots in maize was reduced by 58%, 65%, 62%, and 69% in CUBA1, B73, B5C2, and BR1, respectively, while that of sorghum was reduced by 51%, 56%, 56%, and 76% in SS304, NK7829, Sordan79, and KS585, respectively, in the salt treatment compared to their respective control. Salinity stress reduced all or some of the gas exchange parameters, leaf transpiration (E), stomatal conductance (gs), and net photosynthetic rate (Pn) in the late part of the experiment for both crops. Salinity treatment greatly increased Na+uptake in all maize genotypes but did not affect the Na+uptake in sorghum, regardless of genotype. In maize, CUBA1 was slightly more resistant to salt stress, while BR1 was more sensitive to salt stress. In sorghum, Sordan79 was the most tolerant genotype, and KS585 was the least tolerant genotype.
Lessons Learnt from Gauging Software Metrics of Cabin Software in a Commercial Airliner
Authors: Burger Stefan , Hummel Oliver
Published: October 2012

In order to achieve high safety standards, avionic software needs to be developed with very high requirements regarding safety, reliability, and determinism as well as real-time constraints, which are often in conflict with the development of maintainable software systems. Nevertheless, the ability to change the software of an airplane is of increasing importance, since it consists of a multitude of partially hardware-specific subsystems which may need replacement during a plane’s lifespan of typically numerous decades. Thus, as a first step towards optimizing maintainability of avionic software we have benchmarked the cabin software of a commercial airliner with common software metrics. Such a benchmarking of avionic software contributes valuable insights into the current practice of developing critical software and the application of software metrics in this context. We conclude from the obtained results that it is important to pay more attention to long-term maintainability of aviation software. Additionally we have derived some initial recommendations for the development of future avionic software systems.
Identification and Molecular Characterization of Molluskin, a Histone-H2A-Derived Antimicrobial Peptide from Molluscs
Authors: Sathyan Naveen , Philip Rosamma , Chaithanya E. R. , Anil Kumar P. R.
Published: October 2012

Antimicrobial peptides are humoral innate immune components of molluscs that provide protection against pathogenic microorganisms. Among these, histone-H2A-derived antimicrobial peptides are known to actively participate in host defense responses of molluscs. Present study deals with identification of putative antimicrobial sequences from the histone-H2A of back-water oyster Crassostrea madrasensis, rock oyster Saccostrea cucullata, grey clam Meretrix casta, fig shell Ficus gracilis, and ribbon bullia Bullia vittata. A 75 bp fragment encoding 25 amino acid residues was amplified from cDNA of these five bivalves and was named “Molluskin.” The 25 amino acid peptide exhibited high similarity to previously reported histone-H2A-derived AMPs from invertebrates indicating the presence of an antimicrobial sequence motif. Physicochemical properties of the peptides are in agreement with the characteristic features of antimicrobial peptides, indicating their potential role in innate immunity of molluscs.
Vibration Characteristics of Ring-Stiffened Functionally Graded Circular Cylindrical Shells
Authors: Naeem Muhmmad Nawaz , Kanwal Shazia , Shah Abdul Ghafar , Arshad Shahid Hussain , Mahmood Tahir
Published: October 2012

The vibration characteristics of ring stiffened cylindrical shells are analyzed. These shells are assumed to be structured from functionally graded materials (FGM) and are stiffened with isotropic rings. The problem is formulated by coupling the expressions for strain and kinetic energies of a circular cylindrical shell with those for rings. The Lagrangian function is framed by taking difference of strain and kinetic energies. The Rayleigh-Ritz approach is employed to obtain shell dynamical equations. The axial model dependence is approximated by characteristic beam functions that satisfy the boundary conditions. The validity and efficiency of the present technique are verified by comparisons of present results with the previous ones determined by other researchers.
Nucleosome Positioning
Authors: Nishida Hiromi
Published: October 2012

Nucleosome positioning is not only related to genomic DNA compaction but also to other biological functions. After the chromatin is digested by micrococcal nuclease, nucleosomal (nucleosome-bound) DNA fragments can be sequenced and mapped on the genomic DNA sequence. Due to the development of modern DNA sequencing technology, genome-wide nucleosome mapping has been performed in a wide range of eukaryotic species. Comparative analyses of the nucleosome positions have revealed that the nucleosome is more frequently formed in exonic than intronic regions, and that most of transcription start and translation (or transcription) end sites are located in nucleosome linker DNA regions, indicating that nucleosome positioning influences transcription initiation, transcription termination, and gene splicing. In addition, nucleosomal DNA contains guanine and cytosine (G + C)-rich sequences and a high level of cytosine methylation. Thus, the nucleosome positioning system has been conserved during eukaryotic evolution.
Analytical Assessment of DC Components Generated by Renewable Energy Resources with Inverter-Based Interconnection System due to Even Harmonics
Authors: Moschakis Marios N. , Dafopoulos Vasilis V. , Karapidakis Emmanuel S. , Tsikalakis Antonis G.
Published: October 2012

This paper deals with the assessment of DC components generated by renewable energy resources with inverter-based interconnection system to the electric grid. DC injection is a critical issue related to power quality of distribution network systems with high penetration of inverter-based interconnection systems. This type of interface systems may improve the performance of the electric generation unit and affect positively or negatively the power quality of the distribution network depending on the proper or improper designation. The investigation of the various causes of DC components and the analytical assessment of their maximum levels are crucial for the proper operation of inverter-based interface systems and the limitation of DC injection. A method based on analytical calculations using a computer software has been implemented for the assessment of DC components contained on an inverter's output voltage when even harmonics are present on the network voltage. Moreover, a simulation package was used to demonstrate the existence of DC components under various conditions. It was proved by the current analysis that the amounts of DC components generated when even harmonics are present on the network voltage can be high under abnormalities on the power grid but they are not considerable under normal operating conditions.
N-Aryl Lactams by Regioselective Ozonation of N-Aryl Cyclic Amines
Authors: Saliu Francesco , Orlandi Marco , Bruschi Maurizio
Published: October 2012

Ozonation of N-aryl-cyclic amines in organic solvents gave N-aryl-lactams regioselectively. In particular, 4-(4-aminophenyl)-morpolin-3-one, a key intermediate in the preparation of factor Xa inhibitors, was obtained in fair yields. The method represents an alternative approach for the lactamization of tertiary N-arylic substrates and is based on a “metal-free” introduction of the carbonyl function into the heterocyclic ring.
Influence of Acacia catechu Extracts and Urea and Gamma Irradiation on the Mechanical Properties of Starch/PVA-Based Material
Authors: Naznin Marufa , Abedin Md. Zainul , Khan Mubarak Ahmad , Gafur Md. Abdul
Published: October 2012

This work was aimed to study the effect of natural polyphenol extract (Acacia catechu) on physicochemical properties of starch/PVA-based film. Acacia catechu extracts were incorporated in the starch/PVA- (60 : 40%) based films at different concentrations (0.1% to 15%) to the total weight of starch/PVA-based film. The tensile strength (TS) of the starch/PVA blend film was 24 MPa and significantly increased (33.8 MPa) by the addition of acacia (0.5%). Different percentages of urea (1% to 15%) were incorporated in the starch/PVA/acacia-based film. The best tensile strength (11 MPa) and elongation at break (59%) were obtained at 5% urea concentration. This 5% urea-incorporated film was irradiated at different radiation doses; the film showed the best results at 100 krad (tensile strength 15 MPa and elongation at break 69%). Molecular interactions due to incorporation of Acacia catechu were supported by FTIR spectroscopy. Thermal properties (TG/DTA) of all the films were carried out successfully. Water absorption trend of all the films was comparatively high. Urea-incorporated film degraded 94%, and irradiated urea incorporated film degraded 91% within 70 days into the soil.
pH and Antimicrobial Activity of Portland Cement Associated with Different Radiopacifying Agents
Authors: Guerreiro-Tanomaru Juliane Maria , Cornélio Ana Lívia G. , Andolfatto Carolina , Salles Loise P. , Tanomaru-Filho Mário
Published: October 2012

Objective. The aim of this study was to evaluate the antimicrobial activity and pH changes induced by Portland cement (PC) alone and in association with radiopacifiers.Methods. The materials tested were pure PC, PC + bismuth oxide, PC + zirconium oxide, PC + calcium tungstate, and zinc oxide and eugenol cement (ZOE). Antimicrobial activity was evaluated by agar diffusion test using the following strains:Micrococcus luteus,Streptococcus mutans,Enterococcus faecalis,Pseudomonas aeruginosa, andCandida albicans. After 24 hours of incubation at 37°C, inhibition of bacterial growth was observed and measured. For pH analysis, material samples () were placed in polyethylene tubes and immersed in 10 mL of distilled water. After 12, 24, 48, and 72 hours, the pH of the solutions was determined using a pH meter.Results. All microbial species were inhibited by the cements evaluated. All materials composed of PC with radiopacifying agents promoted pH increase similar to pure Portland cement. ZOE had the lowest pH values throughout all experimental periods.Conclusions.All Portland cement-based materials with the addition of different radiopacifiers (bismuth oxide, calcium tungstate, and zirconium oxide) presented antimicrobial activity and pH similar to pure Portland cement.
Domain Wall Splitting in Extra Dimension
Authors: Tofighi A.
Published: October 2012

We study the splitting of domain walls in 5-dimensional flat Minkowski spacetime.
To construct a domain wall structure we utilize a potential of the form and for simplicity we assume the scalar field to be real. We also assume the coefficient a to be temperature-dependent. We find exact analytical expressions for the energy density of the domain wall and from this expression we find close analytical form for the separation of the divided domain walls. We find that near critical temperature the domain walls split. At the critical temperature, the
domain walls rejoin. In the region above this critical temperature, the kink solution is
nontopological. We find that the phenomena of splitting of domain walls occurs in
this region as well. This effect is especially manifest near the inflection point of the
potential.
Insights into the Pathogenesis of Takotsubo Syndrome, Which with Persuasive Reasons Should Be Regarded as an Acute Cardiac Sympathetic Disease Entity
Authors: Y-Hassan Shams
Published: October 2012

The pathogenesis of takotsubo syndrome (TS) has not been established yet. The literature data dealing with the pathogenesis of TS are abundant but scattered among different medical specialities. Subarachnoid hemorrhage and other acute intracranial diseases and injuries are among the important and currently well-recognized trigger factors for TS. In both induced and spontaneous subarachnoid hemorrhages, signs suggestive of increased cardiac sympathetic overactivity have been documented. Surgical and pharmacological sympathectomy has shown to have protective cardiac effects in both animal and human studies. Increase in local release of norepinephrine from the heart of patients with TS has been measured. Signs of both cardiac sympathetic denervation and myocardial lesions adjacent to the cardiac nerve terminals have been seen. Furthermore, the systematized and typically circumferential pattern of ventricular wall motion abnormality is incongruent with the coronary artery supply region and appears most likely to follow the cardiac sympathetic nerve distribution. In conclusion, compelling literature data support the hypothesis that acute cardiac sympathetic disruption and norepinephrine seethe and spillover is causing TS in predisposed patients. TS is most probably an acute cardiac sympathetic disease entity causing myocardial stunning in which takotsubo is one among other cardiac image study findings.
Modeling and Compensation for Hysteresis Nonlinearity of a Piezoelectrically Actuated Fast Tool Servo Based on a Novel Linear Model
Authors: Zhu Zhiwei , Zhou Xiaoqin , Lin Jieqiong , Liu Qiang
Published: October 2012

In order to describe and compensate for complex hysteresis nonlinearities of piezoelectrically actuated fast tool servo (FTS), a novel Linear Fractional order Differentiation Hysteresis (LFDH) model is proposed in this paper. By means of the proposed LFDH model which is established on the fractional calculus theory, an analytical description of hysteresis behaviors of the FTS is derived. Furthermore, the LFDH model-based inverse compensation strategy is proposed to suppress the hysteresis effects of the FTS. Finally, a series of experiments are conducted to verify the effectiveness of the LFDH model and the corresponding compensation approach. The results demonstrate that the proposed LFDH model is efficient for describing hysteresis behaviors and the inverse compensation strategy can significantly suppress the inherent hysteresis of the FTS in open-loop operations.
Synthesis and Characterization of Gold Nanoparticles with Plasmon Absorbance Wavelength Tunable from Visible to Near Infrared Region
Authors: Shi Weihong , Casas Justin , Venkataramasubramani Meenakshi , Tang Liang
Published: October 2012

Gold nanorods with localized surface plasmon resonance (LSPR) can be chemically synthesized. We systematically investigated the effects of reaction parameters and centrifugation on the fine tuning of the rod dimension in scale-up production (80–100 mL). Nanorods of absorption bands from 600–1050 nm were fabricated with precise control of the aspect ratio (AR) from 1.5 to 8.9. Although all chemicals are important in directing the nanostructure, silver ion concentration and seed/Au3+ ratio were the most effective variations to adjust the absorption wavelength. With a single surfactant under the influence of silver nitrate, short nanorods up to AR of 5 were synthesized with corresponding maximum absorption wavelength at 902 nm. To achieve higher aspect ratio with absorption band beyond 1,000 nm, two-surfactant growth solution was sought to further elongate the rod length. Centrifugation speed and times were found to exert significant influences on the final rod dimension, which is important during the purification process. In a relatively large quantity nanorod synthesis, even distribution and sufficient mixing of chemical ingredients play an essential role in determining the yield, uniformity, and stability of the final nanorod formation.
Information Processing with Electron Spins
Authors: Bandyopadhyay Supriyo
Published: October 2012

Information processors process information in a variety of ways. The human brain processes information through a highly interconnected system of neurons and synapses, while a digital computer processes information by having a binary switch toggle on and off in response to a stream of binary bits. The “switch” is the most primitive unit of the modern computer. The better it is (faster, more energy efficient, more reliable, etc.), the more advanced is the computer hardware. Energy efficiency, however, is more important than any other attribute, not so much because energy is costly, but because too much energy dissipation prevents increasing the density of switches on a chip that is necessary to make the chip increasingly more powerful. Reducing dissipation entails radically new and often revolutionary approaches for implementing the switch. One such approach is to encode digital bit information in the spin polarization of a single electron (or ensemble of electrons) and then using two mutually antiparallel polarizations to represent the binary bits 0 and 1. Switching between the bits can be accomplished by simply flipping the polarizations of the spins, which takes very little energy. Such switches are extremely energy efficient if designed properly, but they are somewhat slower than traditional transistor-based switches and can be more error prone. This paper discusses the pros and cons of spin-based switches and introduces the reader to the most recent advancements in information processing predicated on encoding information in electron spin polarization.
Microstructural Modeling of Ni-Al2O3Composites Using Object-Oriented Finite-Element Method
Authors: Sharma Neeraj Kumar , Pandit S. N. , Vaish Rahul
Published: October 2012

This paper studied the mechanical and thermal properties of interpenetrating phase composites (IPCs) of Ni-Al2O3using finite-element-based object-oriented program (OOFEM). It is difficult to model structure-property relationship in IPCs because of interpenetration of two or more phases. In order to understand the material behavior, OOFEM combines the microstructural data in the form microscopic images with the fundamental material properties (such as Young’s modulus or thermal conductivity of the constituent phases). Thermal conductivity, thermal expansion coefficient, and modulus of elasticity for the composites are examined using OOFEM and compared with other methods. The distribution of residual thermal stresses is also investigated.
Seleção precoce de progênies de Pinus radiata a Sphaeropsis sapinea
Authors: Corrêa Paula Rachel Rabelo , Auer Celso Garcia , Santos Alvaro Figueredo dos , Higa Antonio Rioyei
Published: October 2012

http://dx.doi.org/10.5902/198050985734Sphaeropsis sapinea é um importante patógeno para Pinus radiata, causando seca de ponteiros e morte de árvores, em plantios comerciais. Este estudo teve como objetivo selecionar progênies de Pinus radiata resistentes ao patógeno. Mudas de 16 progênies de Pinus radiata foram inoculadas com três isolados monospóricos do patógeno, em condição de casa de vegetação. Foram avaliados o comprimento das lesões e o grau de secamento dos ponteiros. Os resultados indicaram que a metodologia de seleção precoce foi adequada para selecionar progênies de Pinus radiata resistentes ao Sphaeropsis sapinea. A herdabilidade média das progênies variou de acordo com o isolado testado e o critério de seleção utilizado.
Efeito do sombreamento e do substrato sobre a germinação e o crescimento de plântulas de Acacia mangium e Acacia mearnsii
Authors: Martins Cibele Chalita , Silva José Diego Rodrigues da , Pereira Maria Renata Rocha , Oliveira Silvia Sanielle Costa de
Published: October 2012

http://dx.doi.org/10.5902/198050985735A germinação rápida e uniforme das sementes, seguida por pronta emergência das plântulas, são características altamente desejáveis na formação de mudas. Estudos com a finalidade de viabilizar a utilização de resíduos orgânicos como o lodo de esgoto e a casca de pinus na cadeia produtiva representam uma demanda atual. O objetivo deste trabalho foi identificar condições de sombreamento e substrato favoráveis ao processo de germinação das sementes e crescimento de plântulas de Acacia mangium e Acacia mearnsii. Após a superação da dormência, por imersão em água quente, as sementes foram semeadas em três tipos de substratos: substrato comercial Plantmax florestal (testemunha), casca de pinus e mistura de casca de pinus com biossólido (1:1). Os tubetes foram colocados em viveiro, sob duas condições de sombreamento: 50% e 30%, e a pleno sol (0%), como testemunha. Os parâmetros avaliados foram: velocidade e porcentagem de germinação (diariamente, até 30 dias) e comprimento da parte aérea de plântulas (semanalmente, de 75 a 150 dias). O delineamento experimental utilizado foi o inteiramente casualizado com os tratamentos dispostos em um fatorial 3 x 3, os resultados foram submetidos à análise de regressão e teste T. Maiores porcentagens de germinação foram obtidas na semeadura de Acacia mangium em casca de pinus sob 30% de sombreamento, e substrato comercial sob 30 e 50% de sombreamento e para Acacia mearnsii em casca de pinus sob 50% de sombreamento, ou substrato comercial a pleno sol. Para ambas as espécies, as plântulas cresceram mais rapidamente e atingiram maior tamanho final no substrato casca de pinus com biossólido e em qualquer condição de sombreamento (30 e 50 %) e a pleno sol, antecipando a produção de mudas.
Calidad del carbono orgánico del suelo en diferentes técnicas de manejo de residuos forestales
Authors: Lupi Ana Maria , Conti Marta E. , Fernandez Roberto A.
Published: October 2012

http://dx.doi.org/10.5902/198050985736Las distintas técnicas de cosecha y manejo de residuos pueden provocar cambios en la cantidad y calidad de la materia orgánica (MO) del suelo. El objetivo de este trabajo fue evaluar las modificaciones en la concentración y la calidad de la MO en un Ultisol con diferentes manejos de los residuos de la cosecha forestal del Pinus elliottii Engelm, al inicio de la segunda rotación. Los tratamientos analizados fueron: a) extracción manual de los residuos de la cosecha y del piso forestal, suelo descubierto (ER), b) quema de residuos y del mantillo, y laboreo con rastra (PI), c) conservación de residuos y del mantillo sobre el suelo (PC). Se determinó el carbono orgánico (CO) en todo el suelo y en las fracciones de ácidos fúlvicos (AF), ácidos húmicos (AH), huminas (HU) y en la fracción liviana (CL). La conservación de los residuos de la cosecha no aumentó el CO ni el CL. Se observó una pérdida de la fracción de ácidos fúlvicos (AF) particularmente en PI. Los tratamientos sin residuos forestales (ER y PI) muestran un aumento en el grado de estabilización de la MO con un incremento de las HU y de la relación CAH/CAF.
Rendimento volumétrico e energético de clones de híbridos de Eucalyptus sp. no polo gesseiro do Araripe, PE
Authors: Gadelha Fernando Henrique de Lima , Silva José Antônio Aleixo da , Ferreira Rinaldo Luiz Caraciolo , Melo Ivan Vieira de , Jorge Danillo Lobo , Tavares José Alves , Silva Sergio Peres Ramos da
Published: October 2012

http://dx.doi.org/10.5902/198050985740O presente trabalho teve como objetivo avaliar o rendimento volumétrico e energético produzido por três diferentes clones de híbridos de Eucalyptus sp.: C39 Híbrido de Eucalyptus urophylla (cruzamento natural); C41 Híbrido de Eucalyptus urophylla (cruzamento natural) e C11 Híbrido de Eucalyptus brassiana (cruzamento natural). Para a quantificação do volume de madeira foi utilizado o processo de cubagem rigorosa pelo método de Smalian. A densidade básica da madeira e o poder calorífico foram determinados, respectivamente pelas normas ABNT (1984 e 2003). O consumo de lenha foi obtido por meio do acompanhamento da calcinação da gipsita. O delineamento utilizado no experimento foi o inteiramente aleatório. As produtividades volumétricas de tais clones foram, respectivamente, 158,46, 132,20 e 164,89 m³/ha aos 7,5 anos de idade, apresentando rendimentos durante a calcinação da gipsita de 0,16, 0,10 e 0,13 metros cúbicos de lenha por tonelada de gesso produzida, quando a lenha foi utilizada em forma de toras. Para a lenha em cavacos os rendimentos foram de 0,11, 0,08 e 0,09 metros cúbicos por tonelada de gesso, resultados bem acima dos melhores rendimentos da lenha de vegetação nativa, que são de 0,16 metros cúbicos por tonelada.
Determinação das deformações residuais longitudinais decorrentes das tensões de crescimento em Eucalyptus spp.
Authors: Beltrame Rafael , Lazarotto Marília , Haselein Clovis Roberto , Santini Elio José , Schneider Paulo Renato , Aguiar Aurélio Mendes
Published: October 2012

http://dx.doi.org/10.5902/198050985741O presente estudo foi desenvolvido com o objetivo de determinar as deformações residuais longitudinais (DRL), decorrentes das tensões de crescimento em árvores em pé e vivas de diferentes clones de Eucalyptus spp. Para tanto, foram selecionados 12 clones do gênero Eucalyptus com nove anos de idade, por meio das maiores áreas basais (G). Foram selecionadas 12 árvores de cada clone, onde foram medidas as variáveis de densidade básica (DB), espessura de casca (EC), diâmetro a altura do peito (DAP) e altura total (H). As medições da DRL foram realizadas, com o auxílio do extensômetro (Growth Strain Gauge), pelo método CIRAD-Forêt. As leituras foram realizadas em quatro posições ao redor do tronco da árvore. Em relação aos níveis das DRL, os resultados obtidos no estudo indicaram que os clones apresentaram grandes variações entre si, apresentando um valor médio considerado elevado quando comparado com resultados encontrados na literatura. O clone 8 se destacou por apresentar os menores níveis de deformação, sendo considerado um material recomendado para programas de melhoramento genético e para produção de madeira sólida. Já o clone 1, apresentou os maiores valores das DRL. Ocorreram variações das DRL, ao longo da circunferência do tronco das árvores, sendo mais acentuadas na linha referente à posição Leste. Analisando as correlações entre as variáveis, verificou-se que as DRL apresentaram correlações significativas com a EC, DAP e o volume total da árvore em pé (VOL).
Pontos críticos do processo de produção de pisos maciços de madeira
Authors: Soares Philipe Ricardo Casemiro , Milan Marcos , Jankowsky Ivaldo Pontes , Maciel Antonio Jose da Silva , Kanieski Maria Raquel
Published: October 2012

http://dx.doi.org/10.5902/198050985742Os conceitos da qualidade representam um dos fatores importantes para o êxito das organizações, e dentre esses conceitos a estabilização dos processos de produção contribui para a melhoria, redução de desperdícios e aumento da competitividade. Com isso, o objetivo desse trabalho foi avaliar o processo de produção de pisos maciços de madeira de espécies comerciais quanto à sua previsibilidade e capacidade, com base em seus pontos críticos. Para tanto, a pesquisa foi dividida em três etapas. A primeira foi o mapeamento do processo da empresa e a elaboração de fluxogramas para as atividades. A segunda foi a identificação e a avaliação dos pontos críticos por meio da metodologia FMEA (Failure Mode and Effect Analysis) adaptada. A terceira foi a avaliação dos pontos críticos empregando o controle estatístico e a determinação da capacidade do processo pelo índice Cpk. Os resultados mostraram a existência de seis processos, sendo dois identificados como críticos. Nesses dois, quinze pontos foram considerados críticos e dois deles, relacionados com as dimensões das peças e defeitos provocados pela lixa, foram selecionados para avaliação. O processo produtivo da empresa é instável e não é capaz de produzir os pisos dentro das especificações e, portanto, essas especificações devem ser reavaliadas.
Eficiência de um retardante de fogo de longa duração utilizado em incêndios florestais
Authors: Filho Cláudio Machado , Martins Maria Cristina , Ribeiro Guido Assunção , Lima Gumercindo Souza , Cardoso Marco Túlio , Torres Carlos Moreira Miquelino Eleto , Pinto Flavia Barreto
Published: October 2012

http://dx.doi.org/10.5902/198050985743O objetivo do trabalho foi avaliar a eficiência de um retardante de fogo de longa duração em relação ao volume aplicado e ao tempo de aplicação. O experimento foi realizado nas dependências do Laboratório de Incêndios Florestais e de Conservação da Natureza/UFV, com aplicação da solução retardante a 600 e 900 ml/m2 e avaliada sua eficiência ao longo de quatro semanas, empregando-se cinco repetições. Parcelas de 3,0 x 1,0 m foram montadas em uma rampa com 27º de inclinação média, com o maior comprimento no sentido do aclive, utilizando como material combustível 1,20 kg/m2 de Melinis minutiflora Beauv., distribuído uniformemente sobre a parcela. A eficiência do produto foi avaliada comparando-se as quantidades aplicadas e o tempo de aplicação utilizando-se altura das chamas, velocidade, intensidade e tempo de queima, na porção com e sem o produto. Foi determinada a umidade relativa do ar e do material combustível no momento da queima. Os resultados mostraram que o tempo de aplicação não influenciou na ação do produto e que o tempo para a linha de fogo percorrer a parte da parcela com o produto foi, em média, 7 vezes mais lento que na parte sem o produto e a intensidade cerca de 8 vezes menor, apesar de o fogo percorrer toda a área. O mesmo aconteceu com a altura das chamas que foi três vezes mais baixa que na área sem o produto.
Morfologia do fruto, semente e plântula de Eschweilera ovata (Cambess.) Miers
Authors: Oliveira Rute Gregório de , Matos Valderez Pontes , Monteiro Hian de Assis , Sales Anna Gorett de Figueiredo Almeida , Sena Lúcia Helena de Moura
Published: October 2012

http://dx.doi.org/10.5902/198050985744O estudo morfológico de sementes e plântulas, com o objetivo de obter um maior conhecimento de suas estruturas, além de fornecer informações sobre a germinação, viabilidade, armazenamento e métodos de semeadura, auxilia a análise do ciclo vegetativo das espécies, fornecendo informações relativas à identificação. O principal objetivo deste trabalho foi desenvolver metodologia de identificação morfológica de frutos, sementes e plântulas de imbiriba (Eschweilera ovata (Cambess.) Miers), por meio de descrições e ilustrações das características morfológicas externas e internas. Os frutos e as sementes foram colhidos no Parque Estadual de Dois Irmãos, no município de Recife-PE e conduzidos em sacos de polietileno para o Laboratório de Sementes do Departamento de Agronomia da Universidade Federal Rural de Pernambuco. Foi realizada caracterização morfológica dos frutos, sementes e plântulas, sendo tomadas as medidas de comprimento e largura. A descrição foi feita com auxílio do microscópio estereoscópico binocular. As sementes foram desinfestadas com solução de hipoclorito de sódio a 5% durante cinco minutos e semeadas em substrato sobre vermiculita, esterilizado e umedecido com solução de nistatina a 0,2%. Constatou-se que os frutos constituem-se em um pixídio, fruto seco, em forma de sino. As sementes de imbiriba apresentam arilo funicular lateral e endosperma abundante, possuem germinação hipógea, sendo a plântula classificada como criptocotiledonar, ocorrendo poliembrionia em torno de 4%.
Estaquia de resedá-nacional (Physocalymma scaberrimum Pohl.) em diferentes substratos e concentrações de AIB
Authors: Preti Edilene Aparecida , Yamamoto Lilian Yukari , Cardoso Carina , Aquino Gisele Silva de , Paes Vanessa dos Santos , Assis Adriane Marinho de , Machado Maria Helena , Neves Carmen Silvia Vieira Janeiro , Roberto Sérgio Ruffo
Published: October 2012

http://dx.doi.org/10.5902/198050985745O resedá-nacional (Physocalymma scaberrimum Pohl.) é uma espécie nativa do Brasil que apresenta grande potencial para uso no paisagismo e em reflorestamento, além da madeira ser empregada na marcenaria de luxo. O objetivo deste trabalho foi avaliar o efeito de diferentes substratos e concentrações de ácido indolbutírico (AIB) na estaquia de resedá-nacional. O delineamento experimental foi o inteiramente casualizado, com cinco repetições em arranjo fatorial 3 x 3, sendo os fatores: tipos de substratos (areia de granulação média; casca de arroz carbonizada e vermiculita de granulação média) e concentrações de AIB (0; 1.000 e 2.000 mg L-1), em parcelas compostas por dez estacas. Após 104 dias da instalação do experimento, foram avaliadas as seguintes variáveis: sobrevivência das estacas; retenção foliar; porcentagem de estacas com calos não enraizadas; estacas enraizadas; número de raízes por estaca; comprimento de raízes por estaca e massa seca das raízes por estaca. Não foram observadas diferenças quanto ao enraizamento em relação à aplicação de AIB, obtendo-se, em média, 23,5%. Entre os substratos, embora as estacas enraizadas em areia e casca de arroz carbonizada tenham apresentado maior retenção foliar, todos os substratos testados podem ser utilizados.
Análise estrutural em relictos de Cerrado no Parque Estadual do Guartelá, município de Tibagi, Estado do Paraná, Brasil
Authors: Carmo Marta Regina Barrotto do , Andrade Anna Luiza Pereira , Santos Gisele Aparecida da S. D. dos , Assis Marco Antônio
Published: October 2012

http://dx.doi.org/10.5902/198050986618O estudo foi desenvolvido em relictos de cerrado existentes no Parque Estadual do Guartelá, Tibagi-PR, (24º39’10”S e 50º15’25”W), os quais representam um dos poucos remanescentes extremo-meridional deste tipo de formação. Para a análise fitossociológica, foram alocadas 50 parcelas de 5 x 5 m, incluindo-se os indivíduos com altura ≥ 1 m, divididos em duas amostragens para avaliar os seguintes estratos: a) superior - plantas com DAS ≥ 3 cm; e b) médio - plantas com DAS < 3 cm. Ainda, em cada parcela foram estabelecidas subparcelas de 1 x 1 m para amostrar o estrato inferior, constituído por indivíduos com altura < 1 m e > 10 cm. No total foram amostrados 1.340 indivíduos, distribuídos em 28 famílias, 66 gêneros e 115 espécies. O índice de diversidade foi maior para o estrato médio (H’=3,30), seguido do superior (H’=3,09) e inferior (H’=2,91). A ocorrência frequente de moitas é uma característica notável da fisionomia das áreas do PEG, sendo que 82 % das populações analisadas distribuem-se com padrão agregado. Por se tratar de uma região limítrofe de ocorrência do Cerrado, sob influência atual de um clima subtropical, mais úmido e frio, comparado à zona core de tal bioma, nota-se que estas áreas se caracterizam por uma diminuição na estatura, riqueza e diversidade de sua flora. Apesar disso, preserva espécies características dos cerrados brasileiros, mas, por apresentarem distribuição em relictos e estes terem sido em parte devastados, algumas estão incluídas na lista vermelha de plantas ameaçadas de extinção no Estado do Paraná, o que evidencia a importância da preservação e manejo destas áreas.