bluuebunny/crossref_metadata_2025 huggingface dataset:
Vibrostability of a Multidimensional Machine Tool-Workpiece-Tool System, Part I: Modeling the Mechanical Structure and Cutting Process
Authors: Marchelek Krzysztof , Tomków Jan
Published: March 2007

Predicting the vibrostability of machine tools requires mathematical models for the elements that form a multidimensional dynamic machine tool-workpiece-tool system (i.e., mass-damping-spring system, cutting process, friction process, processes of driving motors, and the control system). This article presents the principles of modeling this system using the rigid finite element method. The result is a mathematical model that is useful in analyzing dynamic properties of a machine, including the vibrostability (dynamic stability) analysis. Part I describes the modeling of the multidimensional mass-damping-spring system of a machine tool and cutting process. This enables the designer to construct an entire model of the system and to analyze its dynamic properties during designing, including predicting the vibrostability.
Nonlinear Model of Vibrations in a Rotor-Bearings System
Authors: Kicinski J. , Drozdowski R. , Materny P.
Published: March 2007

This article presents a theoretical model for the nonlinear description of vibrations occurring in the rotor-bearings-supports system. A new approach to the determination of viscous-elastic properties of the oil film that does not draw on the commonly used principle of superposition of pressure or hydrodynamic forces in the bearing is put forward. The dynamic features of the oil film are determined by means of nonlinear coefficients of stiffness and damping calculated by using a fast and modified perturbation method. The method applied to describe the oil filin properties enables us to take advantage of the equations of motion of the entire system derived on the basis of the finite element method. The theoretical model takes also into account the effect of heat transfer within the bearing. With regard to kinetostatic problems, the temperature distribution in the film is calculated on the basis of a sophisticated so-called diathermal model of the bearing that permits the determination of a mean dynamic viscosity of the oil, further applied to the problems of the system dynamics. A general calculation algorithm and a computer program consisting of two clearly separated parts, kinetostatic and dynamic, is described. This article also gives examples of experimental verification of the model at a special large-size test rig and presents the analysis of nonlinear vibrations of a real large turbo-set carried out with the help of the developed theoretical method and computer program.
Some Further Insight Into Self-Adjoint Second-Order Systems
Authors: Garvey S.D. , Friswell M.I. , Penny J.E.T.
Published: March 2007

The vibration of structures is governed by a set of second-order ordinary differential equations in which the (N x N ) coefficient matrices are real. These equations often produce both complex roots and complex modes. In the established method for computing the roots, the eigenvalue problem is solved for a certain (2N x 2N ) matrix whose form is such that it contains an (N × N ) submatrix of zeros as one of the two diagonal (N x N ) blocks. This very special form has substantial significance in the modes and roots that emerge. For systems having no real roots, a part of this significance has already been identified by the authors in the form of a relationship between the real and imaginary parts of complex modes. This article extends this significance to the point where the equation normally used in computing the complete set of characteristic roots and vectors is transformed to another very compact form. One of the attractions of this new form is that all of the numbers involved are real—although some or all of the roots and vectors may be complex. The new form has several potential applications, including providing new methods for examining the sensitivity of solutions to perturbations, achieving realizations of second-order systems from partial knowledge of the roots and modes, and forming the basis for a new solution method for obtaining the characteristic roots and vectors of self-adjoint second-order systems.
The Centrifugal Delayed Resonator as a Tunable Torsional Vibration Absorber for Multi-Degree-of-Freedom Systems
Authors: Hosek Martin , Olgac Nejat , Elmali Hakan
Published: March 2007

The centrifugal delayed resonator (CDR) is a novel active vibration absorption technique for elim inating undesired torsional oscillations in rotating mechanical structures. The key idea is to reconfigure the dynamics of a damped centrifugal pendulum arrangement so that it mimics an ideal real-time tunable ab sorber. This objective is achieved by applying a control torque based on proportional position feedback with variable gain and time delay. Theoretical fundamentals of the technique are explained, its implementation on a multi-degree-of-freedom primary structure is presented, stability of the controlled system is discussed, and real-time tuning ability is elaborated upon and demonstrated via simulations. The strengths of the CDR control consist of complete vibration elimination of the fundamental frequency component of torsional oscil lations at the location where the absorber is attached to the rotating structure, automatic tuning to time-varying frequencies, decoupling of the feedback control from the mechanical and dynamic properties of the rotating structure, relatively simple implementation of the control algorithm, and fault-tolerant performance in the case of control failure.
Analysis and Design of Digital Simulation via Control Theory
Authors: Rahrooh Alireza
Published: March 2007

It is critical that computer usage be integrated into assignments that involve the application of basic concepts in electrical engineering. Digital simulation of systems of first-order differential equations can be viewed as an appropriate use of the computer in simulation of physical systems. Some recent results demonstrating the usefulness of the control theory approach will be discussed to provide more insights into the problem of digital simulation. Then new techniques, based on estimation and adaptive filtering, will be presented and shown to be superior to other popular methods, especially for real-time simulation of physical systems.
Filtering for Interconnected Nonlinear Sampled-Data Systems With Parametric Uncertainties
Authors: Peng Shi
Published: March 2007

The problem of H∞ filtering for a class of interconnected nonlinear continuous-time systems sub ject to real time-varying parameter uncertainty with sampled-data measurements is considered. Linear filters are designed that would guarantee a prescribed H∞ performance in the continuous-time context, irrespective of the parameter uncertainty, nonlinear interactions, and unknown initial states. Both the cases of finite and infinite horizon filtering are investigated in terms of a set of differential Riccati equations with finite discrete jumps. Two examples are given to show the potential of the proposed technique.
Periodic Flap Control of a Helicopter Blade in Forward Flight
Authors: Pandiyan R. , Sinha S.C.
Published: March 2007

The primary objective of this paper is to present new periodic control strategies for the control of flapping motion of an individual helicopter rotor blade in forward flight, which is represented by a differential equation with periodic coefficients. First, an algebraic procedure based on Chebyshev polynomial expansion is employed to control the periodic flapping motion. In this approach, the state vector and the elements of the periodic system matrix have been expanded in terms of shifted Chebyshev polynomials of the first kind over the principal period. Later, optimal control theory in conjunction with Floquet theory has been used to design full-state and observer-state feedback controllers. In the second method, the feedback controllers have been designed in the time-invariant domain through the application of a linear, invertible, periodic transformation known as Liapunov-Floquet (L-F) transformation to the periodic system model. It is shown that by using both methods the periodic control gains can be obtained as explicit functions of time and, therefore, a control scheme more suitable for real-time implementation can be achieved. The design procedures have been found to be much simpler in character when compared to those techniques that have appeared in the literature.
Practice Patterns of Advanced Practice Psychiatric Nurses
Authors: Campbell Cindy D. , Musil Carol M. , Zauszniewski Jaclene A.
Published: March 2007

BACKGROUND: Research about the nature and scope of advanced psychiatric nurse prac tice is critical to validating advanced practice and further developing the role of the advanced practice nurse.

OBJECTIVE: The purpose of this study was to describe the characteristics and the practice and prescriptive patterns of advanced practice psychiatric nurses (APPNs). Research questions included: (a) What are the characteristics of APPNs? (b) What are the prac tice patterns of APPNs? (c) What are the prescribing patterns of APPNs? (d) Do APPNs with prescriptive authority dependent on physicians differ in prescribing patterns from those APPNs with prescriptive authority independent of physicians? (e) Are APPNs with prescriptive authority dependent on physicians in the form of a protocol more likely to practice in urban areas than in rural areas?

STUDY DESIGN: This study was a descriptive cross-sectional survey of a random sample of 500 APPNs selected from the approximately 800 names included in the American Nurses Credentialing Center directory.

RESULTS: Nurses in this sample were most likely to be older (mean age 50 years) women holding a masters degree or higher and working less than 40 hours per week in at least one or more subspecialties with an average of 13 years experience in the role. Most of these nurses earned between $30,000 and $69,999. They tended to be employed by an organization at least part of the time, with the rest of their time spent in private prac tice. Most (93%) of the APPNs in this study spent their time divided between two or more outpatient activities. Prescribing patterns for major tranquilizers, mood stabilizers, and antiparkinsonian agents differed based on dependence on protocol of prescriptive authority. APPNs in this sample were no more likely to practice in urban or rural areas when their prescriptive authority was independent or dependent on a physician.

CONCLUSION: APPNs have decisions to make about the future of their role in a climate that demands more intensive treatment for a much smaller fee. ( J Am Psychiatr Nurses Assoc [1998]. 4, 111-120)
How Classroom Environment and Student Engagement Affect Learning in Internet-based MBA Courses
Authors: Arbaugh J.B.
Published: March 2007

While the number of college courses being delivered via the Internet is increasing rapidly, our knowledge of what makes these courses effective learning experiences for students is still limited. Therefore, I conducted a study that examined the effects of technological, pedagogical, and student characteristics on student learn ing in Internet-based MBA courses. Of these characteristics, I found that only those reflecting instructor efforts to create an interactive classroom environment were significantly associated with student learning. Other characteristics such as the perceived ease of use of the course software package, the perceived flexibility of the online classroom environment, and the amount of time students spent logged onto the course Website were not significantly associated with student learning. These findings suggest that while some level of technological sophistication may be important, teaching expertise may be the primary criterion for teaching success in the online classroom environment. Therefore, instructors may need to spend more time developing and cultivating instructional skills such as simultaneously working with several smaller groups of students, developing interesting discussion questions, and fostering intimacy. To support this faculty development, business schools will likely need to make substantial infrastructural investments to ensure that their online course offerings are pedagogically and technologically conducive to student learning.
Chinese Business Face: Communication Behaviors and Teaching Approaches
Authors: Cardon Peter W. , Scott James Calvert
Published: March 2007

Chinese businesspersons are extremely sensitive to protecting and enhancing face. The Chinese sensitivity to face is a result of their emphasis on enduring relation ships and social networks. The hundreds of phrases in the Chinese language describing face demonstrate the sophistication of the Chinese conceptualization of face and related behaviors. For the businessperson, saving face and giving face are the most important face-related skills. Chinese businesspersons use various com munication strategies in order to save face and give face, including indirectness, intermediaries, praising, requests, and shaming. Western businesspersons can pre pare to operate effectively in the Chinese business environment by learning about the Chinese conceptualization of face and related communication strategies.
Teaching Business Students to Write Performance Appraisals
Authors: Nelson Sandra J. , MacLeod Laura
Published: March 2007

Since many business students will conduct performance appraisals in future employment, instruction on performance appraisals is appropriate for the business communication course. This article contains a discussion of a unit on perfor mance appraisals, including writing comments to support ratings, drawing conclusions concerning performance, and making recommendations to improve performance. An exam ple of an assignment that requires students to complete an appraisal form is provided. Last, suggested teaching tech niques are given for the appraisal unit.
Self-Assessment of Com munication Behavior: An Experiential Learning Exercise for Intercultural Business Success
Authors: Zhao Jensen J. , Parks Calvin
Published: March 2007

This self-assessment is an experiential learning exercise designed for both corporate training and classroom. With Kolb's experiential learning model as a theoretical base, the self-assessment questionnaire in the exercise was developed on the basis of seven. dimensions of communication compe tence identified and confirmed by various empirical studies as predictors of intercultural business success. After com pleting this exercise, students should be able to (a) identify their communication behavior in intercultural interactions, (b) be aware of their communication competence level in intercultural interactions, and (c) increase their under standing of the relationship between communication behav ior and intercultural business management success.
Teaching the Art of the Memo: Politics and Precision
Authors: Rice H. William
Published: March 2007

In order to reproduce the politically charged environment of most corporations, I turn my class into a company. Using previously designated study groups, I make one the presi dent, another the vice president, and a final one the man ager of operations. Then I give them a problem which they can handle only through memos. Outside of class, they communicate by fax machines. Inside of class, they read and discuss each other's memos. This assignment enables the instructor to drop out of the role of lecturer as students discover for themselves the complex interaction between a writer and an audience.
Audiotaped Feedback in Business Writing: An Exploratory Study
Authors: Pearce C. Glenn , Ackley R. Jon
Published: March 2007

This four-year exploratory study was designed to investigate whether augmenting written comments on students' busi ness writing assignments with audiotaped remarks would lead to improved feedback, context, and performance; save time; and motivate student writers. The results showed that all factors improved except time, which could not be com pared directly to the results of previous studies.
Executive Speech Coaching: An On-Site, Individualized, Abbreviated Course in Public Speaking
Authors: Boyd Stephen D.
Published: March 2007

Corporate executives are often plagued with poor presentation skills, and the most time-efficient, customized solution is often individual coaching. This article, written by a practicing corporate speech. coach, describes a three-session approach to corporate speech coaching that has helped speakers improve on more than a hundred different occasions. It discusses optimal time schedules for coaching, what should be covered in individual sessions, how coaching should differ for speakers seeking to improve their skills in general and speakers working on a specific speech, and exercises to address specific presentation problems.
Native and Nonnative Student Writers
Authors: Featheringill Ron , Fuller Jean , Vogt Gayle
Published: March 2007

We assert that schools and textbook publishers ineffectively emphasize gram mar. To see if traditional instruction in grammar prepares students for busi ness communication classes and the corporate world, we investigated specific writing skills of both native and nonnative business students. Although most students passed objective grammar and punctuation tests—the two groups showed no statistical differences—some cannot write. High schools, the study found, pass these students. The university also passes writing-deficient stu dents on to employers who must train them. We searched for reasonable solu tions to reduce the number of graduates who lack English skills for the workplace.
Professional Advisory Boards: Fostering Communication and Collaboration Between Academe and Industry
Authors: Dorazio Patricia
Published: March 2007

To make the technical communication program at SUNY Institute of Technol ogy at Utica/Rome successful and to give students an advantage of working with practicing professionals, the faculty thought it wise to add an advisory board composed of professionals, managers, and others associated with profes sional and technical communication. This paper describes the program, the board's contributions, and the benefits received by the students, the program, and the board members themselves.
Prejudice and Behavioral Archetypes: A New Model for Cultural-Diversity Training
Authors: Sussman Lyle
Published: March 2007

Cultural-diversity training programs typically incorporate discussions of why some organizational acts and actors are seen as offensive while others are not. Invariably these discussions elicit perceptions and attributions of the actor's intent and interpersonal style. This paper presents a new model, incorporating intent and style into four archetypes. The archetypes are discussed in detail as are implications for designing and conducting cultural-diversity training.
Metacommunication Effects on International Business Negotiating in China
Authors: Gilsdorf Jeanette W.
Published: March 2007

Forpractitioners and teachers, this article reviews the literature on differences in cultural assumptions underlying negotiation between businesspersons in the People's Republic of China and those from the West, particularly the United States. Unless perceived and understood, profound differences in atti tudes, expectations, and unworded messages will frustrate businesspeople's efforts to do business with China, a huge and developing market.
The Efficacy of Several Writing Feedback Systems
Authors: Quible Zane K.
Published: March 2007

Over the years, a number of systems have been developed or adapted for use in grading the work of students in written business communication courses. Although the "perfect" system most likely has not been developed, a number of those currently used fulfill theirgoal of helping students become more profi cientwriters. Some systems undoubtedly fulfill their goal more effectively than others, however. Regardless of which feedback system an instructor uses, he/she needs to be aware of its advantages and disadvantages as well as ways to maximize its effectiveness. This article provides a review of three different systems: written comments, conferences, and peer evaluation.
Innovative Pedagogy: Academic Service-Learning for Business Communication
Authors: Bush-Bacelis Jean L.
Published: March 2007

Academic Service-Learning (AS-L) is an innovative business communication pedagogy. Like community service, AS-L involves students volunteering in the community; however, AS-L requires the infusion of the classroom content into the community service experience. This article describes AS-L, the assignment for a business communication class, and students' reactions as well as benefits and challenges to its use. The greatest strength of using AS-L is students'tying theory into actual application of principles, student passion for the work, fac ulty enthusiasm for the results, and community satisfaction.
Analyzing International Letters in a Business Communication Class
Authors: Devet Bonnie
Published: March 2007

In the global marketplace, professionals need to understand how cultural differences affect the writing and reading of business letters. Business commu nication courses can prepare students to meet this need by teaching students an effective, systematic method for analyzing the letters of the global economy. The method incorporates such characteristics as format, organization, rhetori cal strategies (ethos, pathos, logos), style, and writer's purpose. Through case studies in letter writing and analysis, students apply key communication prin ciples in an international context.
Teaching Students to Enhance the Ecology of Small Group Meetings
Authors: Clark Thomas
Published: March 2007

Students need to understand how the interplay of ideas, personalities, and environment-the ecology-of a meeting contributes to productivity and satis faction in group process. Only when the ecology is right can the meeting work. To address that ecology explicitly, instructors should help students assess their prior experience in small groups. In a classroom exercise, student teams answer one of a set of questions about meetings: 1. How participants know when a meeting is productive (or not); 2. How they know when warm hospi tality has been extended (or not); 3. What happens before, during, and after meetings that generates broad enthusiasm—or produces apathy. A class period spent on such discussion helps convince students of the need to proactively apply effective meeting management principles in their own workplace. Key words: Group process, meetings, participation, hospitality, enthusiasm
Student Portfolios: A Tool to Enhance the Traditional Job Search
Authors: Powell Karen Sterkel , Jankovich Jackie L.
Published: March 2007

Student portfolios are a tool that academic institutions can implement to enhance students' job search processes. Students can enhance their ability to pass the initial screening process by preparing a portfolio that identifies their goals and provides evidence that they possess the skills and qualities to reach these goals. The portfolio should emphasize communication skills, as they are deemed most important by employers in the initial screening process. When preparing a portfolio, students should consider a variety of media, including paper, videotape, and compact disk. Schools that implement student portfolios must decide if all students will be required to prepare them, if the administra tors will determine the contents, and who will approve the contents of stu dents' portfolios.
Modified atmosphere packaging of strawberry fruit: Effect of package perforation on oxygen and carbon dioxide / Envasado de fresas en atmósfera modificada: Efecto de la perforación del envase en el contenido de oxígeno y dióxido de carbono
Authors: Sanz C. , Perez A.G. , Olias R. , Olias J.M.
Published: March 2007

The effect of film perforation on gas content during modified atmosphere packaging of strawberry fruit was studied. Camarosa strawberries were refrigerated at 2 °C, and wrapped with polypropy lene (PP) film with perforations of 1 and 2 mm diameter. Fruits were held at 2 °C during three days, simulating refrigerated transport, and then at 20 °C for four days to simulate retail display tempera tures. Perforation degree affected final gas contents inside the packages, ranging from 5.68-25.96% CO2 and from 4.84-15.69% O2 on day 7. Different gas content profiles were found among packages with similar perforated surface but distinct diameter perforations, which could infer a perforation edge effect on gas exchange. Neither a CO, stratification effect nor a gas exchange site effect were observed for this kind of perforation-mediated modified atmosphere packaging of strawberries.
Note. Non-destructive appraisal of the ripeness in Cantaloupe melons / Nota. Evaluación no destructiva de la madurez en melones Cantaloupe
Authors: Almela L. , Sánchez C. , Fernández-López J.A. , Romojaro F.
Published: March 2007

This paper attempts to determine the optimum ripeness of Cantaloupe melons ( Cucumis melo L.) by means of a non-destructive technique. Soluble solids, titratable acidity, fruit weight, ethylene emis sion and external color during the fruit development, from 15 days after pollination (DAP) to fruit harvesting (45 DAP) were determined. Changes in color correlated with the changing characteristics of melons. The research was focused on finding a chromatic index to appraise 'harvesting maturity' in a non-destructive way. Among the different relationships investigated ( L/a; a/b; COL = 2000 a/ L.C; CCI = 1000 a/L.b; L/C) the L/C ratio, derived directly from the external reflectance of the fruit, showed the highest correlation with harvesting maturity (35 DAP)
Note. Effects of ingredients and processing on dough rheology of wheat flour tortillas Nota. Efecto de los ingredientes y del proceso sobre la reología de la masa para tortillas de harina de trigo
Authors: Srinivasan M. , Waniska R.D. , Rooney L.W.
Published: March 2007

The effects of fat, cysteine, water and gluten contents and processing parameters (mixing time and mixing temperature) of tortilla doughs were evaluated over 25 min resting time. Dough balls were rested 10 min, hot-pressed and baked. Viscoelastic dough properties (ranging from more solid-like to more fluid-like) were affected by ingredients, processing conditions, and resting time. Solid-like (firm ness, toughness) properties of all doughs decreased during resting. Some doughs had unique proper ties which were retained throughout 25 min resting. Tortillas hot-pressed from doughs with more fluid-like properties (flows easily, soft) required less resting time and were larger in diameter than tortillas prepared from doughs with more solid-like properties. Ingredients and processing condi tions modified dough and tortilla properties; however, changes due to ingredients, were substan tially larger than those due to processing parameters. Some ingredients (less fat, less cysteine, less water, more gluten) and processing conditions (optimum mixing, less warm mixing temperature) increased the solid-like properties of dough. Dough hardness, resilience and extension force were higher and extension distance lower for firm, tough (solid-like) doughs.
Reduction of oil uptake in deep fried tortilla chips Reducción de la absorción de aceite en la fritura de tiras de maíz
Authors: Esturk O. , Kayacier A. , Singh R.K.
Published: March 2007

The reduction of oil uptake in fried tortilla chips was attempted with baking and carboxymethyl cellulose (CMC) addition. The effects of CMC type and concentration, frying time, and prefrying treatment on oil uptake and moisture content were studied. Chips were prepared using corn masa flour. Results showed that the addition of CMC reduced the oil uptake significantly for all samples. The reduction in oil uptake ranged from 5-40% according to the CMC type and concentration. The most effective CMC type was high viscosity, which caused a 40% reduction in oil content for 30 s frying time of baked samples. The addition of CMC also reduced the initial moisture content of raw chips. The highest moisture content reduction was for samples prepared with low-viscosity CMC. Frying time was an important factor on oil uptake and moisture content. When frying time increased, oil content increased while moisture content decreased.
Changes in free amino acids of hake (Merluccius merluccius L.) muscle during frozen storage/Cambios producidos en los aminoácidos libres del músculo de merluza (Merluccius merluccius L.) durante su conservación en estado congelado
Authors: Sotelo C.G. , Franco J.M. , Aubourg S.P. , Gallardo J.M.
Published: March 2007

The effect of storage at subzero temperatures (-5°C, -12°C, and -20°C) on hake ( Merluccius merluccius L.) muscle free-amino acid fraction was evaluated. A significant increase in free aspartic acid, serine, threonine, arginine, β-alanine, tyrosine, methionine, valine, phenylalanine, isoleucine, leucine, and lysine was found at -5°C, whereas at -12°C, a significant decrease in free glutamic acid, glycine, methyl-histidine, β-alanine, taurine, alanine, and leucine was the most noticeable. No changes in the free amino acid fraction were observed at -20°C. Activity of different kind of enzymes, aminopeptidases, aminoacid deaminases, and decarboxylases might be involved in the changes observed at -5°C and -12°C.
Efecto de la temperatura y contenido en sólidos solubles sobre la cinética de pardeamiento no enzimático de zumos clarificados de manzana/Effect of temperature and soluble solids content on nonenzymatic browning kinetics for clarified apple juices
Authors: Ibarz A. , Naves J.
Published: March 2007

Se ha estudiado la cinética de pardeamiento no enzimático de zumos clarificados de manzana de dos variedades (Granny Smith y Jonagold), con diferentes contenidos en sólidos solubles y a distintas temperaturas (60, 70, 80, 85, 90, y 95°C). El seguimiento de la cinética se realizó midiendo la variación de la absorbancia a 420 nm (A 420). De los distintos modelos cinéticos ensayados, se obtuvieron los mejores ajustes con el orden cero. El efecto de la temperatura sobre las constantes cinéticas puede describirse mediante ecuaciones tipo Arrhenius. El efecto del contenido en sólidos solubles sobre los parámetros de la ecuación de Arrhenius puede describirse mediante ecuaciones tipo potencial. Para el intervalo de concentraciones y temperaturas estudiadas, los zumos de la variedad Granny Smith presentaron un pardeamiento más pronunciado que los de la variedad Jonagold.
Review : High-pressure, microbial inactivation and food preservation
Authors: Cheftel J. Claude
Published: March 2007

High pressure (1 to 10 kbars, i.e. 100-1000 MPa) affects biological constituents and systems. Several physicochemical properties of water are modified, such as the density, the ionic dissociation (and pH), and the melting point of ice. Pressure-induced unfolding, aggregation, and gelation of food proteins mainly depend on the effects of pressure on various noncovalent bonds and interactions. Enzyme inactivation (e.g., of ATPases) also results from similar effects, but some enzymes, including oxidative enzymes from fruits and vegetables, are strongly baroresistant. Chemical reactions, macromolecular transconformations, changes in membrane structure, or changes in crystal form and melting point that are accompanied by a decrease in volume are enhanced under pressure (and vice versa). Several of these phenomena, still poorly identified, are involved in the high inactivation ratio (5–6 logarithmic cycles) of most vegetative microbial cells: gram-negative bacteria, yeasts, complex viruses, molds, and gram-positive bacteria, in this decreasing order of sensitivity to pressure. Much variability is noted in the baroresistance of microorganisms, even within one single species or genus. Other parameters influence this resistance: pressure level, holding time (a two-phase kinetics of inactivation is often observed that prevents the calculation of decimal reduction times), temperature of pressure processing (temperatures above 50°C or between –30 and +5°C enhancing inactivation), composition of the medium or of the food (the pH having apparently little influence, but high salt or sugar concentrations, and low water contents, exerting very strong baroprotective effects).

Taking into account the baroprotective effects of some food constituents and the strong resistance of some microbial strains, recent research aims at combined processes in which high pressure is associated with moderate temperature, CO2, other bacteriostatic agents, or to nonthermal physical processes such as ultrasounds, alternative currents, high-voltage electric pulses, and so forth. The safety and refrigerated shelf life of pressurized foods could be maintained or extended, while the sensorial quality should improve due to the reduced severity of thermal processing. Further research is, however, needed for the regulatory authorities to assess and accept these novel foods and processes.
Preservation of apple slices using ascorbic acid and 4-hexylresorcinol / Preservación de rodaj as de manzana con ácido ascórbico y 4-hexilresorcinol
Authors: Luo Y. , Barbosa-Cánovas G.V.
Published: March 2007

The use of sulphites for the prevention of browning on fruits and vegetables is banned in the USA. The possible alternative use of ascorbic acid (AA), 4-hexylresorcinol (HR), and a mixture of both on apple slices was studied taking quality retention as a function of storage time as compared with similar products treated with sulphites. The mixture of ascorbic acid and 4-hexylresorcinol (AH) significantly inhibited the browning of vacuum packaged apple slices for up to 8 weeks during storage at 0.5 °C ( p ≤ 0.001). Browning inhibition by AH was comparable to that achieved by sulphite and stronger than that of ascorbic acid (AA). In addition AH did not bleach the fruit tissue and therefore the colour of AH treated fruits was closer to the fresh apple pieces than those treated with sulphite. AH also reduced the total viable microbial counts by more than 10-fold as compared with AA treated and control apple pieces. AH treated apple pieces had a slightly firmer texture than the control and there were no adverse effects on the soluble solids and titratable acidity of the fruit. The evidence suggests that AH is a promising anti-browning formula for mini mally processed apples.
Note. Effect of brining time on proteolytic changes in Idiazábal cheese during ripening / Nota. Cambios proteolíticos durante la maduración del queso Idiazábal por efecto del tiempo en salmuera
Authors: Ibáñez F.C. , Ordóñez A.I. , Vicente M.S. , Torres M.I. , Barcina Y.
Published: March 2007

Idiazábal cheeses were made employing brining times of 12 h (batch A) and 36 h (batch B). Proteolytic changes in both batches were examined over 270 d of ripening; proteolysis was low in both batches, but lower in batch B than in batch A. Electrophoretic analysis revealed incom plete breakdown of αs and β-caseins at the end of the ripening period, particularly in batch B. The proportion of soluble nitrogen as a percentage of total nitrogen was 17.55% in batch B and 19.48% in batch A, while the proportion of non-protein nitrogen was 11.78% in batch B and 15.16% in batch A. The proportion of non-protein nitrogen as a percentage of soluble nitrogen was 67.17% in batch B and 77.88% in batch A. The free amino acids, the smallest non-protein nitrogen frac tion, attained values of 1203 mg/100 g of dry matter in batch B and 1902 mg/100 g of dry matter in batch A. After 60 d of ripening, the main free amino acids were glutamic acid, valine, leucine, lysine, and phenylalanine in both batches, although levels were higher in the batch with the shorter brining time. There was no clear trend in the non-protein-forming amino acids with either ripening time or brining time.
Estudio de la influencia de la temperatura en el comportamiento reológico de mermeladas de albaricoque (Prunus armeniaca), arándano (Vaccinium myrtillus) y escaramujo (Rosa canina) / Influence of temperature on rheological behaviour of jams of apricot (Prunus armeniaca), bilberry (Vaccinium myrtillus) and rose hip (Rosa canina)
Authors: Villarán M.C. , Cepeda E. , Llorens F.J. , Ibarz A.
Published: March 2007

We studied the rheological behaviour of apricot jam ( Prunus armeniaca) made with sucrose, and jams of bilberry ( Vaccinium myrtillus) and rose hips ( Rosa canina ) prepared for dietary usé with fructose in a temperature range of 5-65 °C. All three jams presented thixotropy, and the decrease in stress with time fit first order kinetics. The flow behaviour can be described by power equa tions and the Herschel-Bulkey équation. The relation between temperature and apparent viscosity was described with the Arrhenius-Guzman équation.
Identificación y caracterización de bacterias acidolácticas aisladas de chorizos tradicionales elaborados en Castilla y León / Identification and characterization of lactic acid bacteria isolated from traditional chorizo made in Castilla-León
Authors: Santos E.M. , González-Fernández C. , Jaime I. , Rovira J.
Published: March 2007

A total of 516 strains of lactic acid bacteria isolated from chorizo made in Castilla-León (Spain) were characterized. Strains were isolated at three different stages: minced meat, half ripened chorizo and ripened chorizo. According to the Schillinger and Lücke classification, 355 strains (68.8%) were Lactobacillus sake, 85 strains (16.5%) were Lactobacillus curvatus, 32 strains (6.2%) belonged to the genus Pediococcus, and 44 strains which were not included in the previous species were grouped as Lactobacillus sp. Strains of L. sake and L. curvatus could be separated into four groups each, on the basis of fermentation of maltose and lactose. Group S1 (maltose-, lactose-négative L. sake) predominated (39.5%). Many strains of this group fermented the following carbohydrates: glucose, ribose, galactose, sucrose, melibiose and trehalose.
Effect of modified atmosphere packaging on the growth and survival of listeria in raw minced beef / Efecto del envasado en atmósferas modificadas sobre el crecimiento y la supervivencia de listeria en carne picada de ternera
Authors: Franco-Abuín C.M. , Rozas-Barrero J. , Romero-Rodríguez M.A. , Cepeda-Sáez A. , Fente-Sampayo C.
Published: March 2007

A study on the behaviour of Listeria monocytogenes and L. innocua in raw minced meat packaged under modified atmospheres was carried out. Three gas atmospheres were tested with various CO2 concentrations (100% CO2; 65% CO2, 25% O2, 10% N2; 20% CO2, 80% O2). Packages containing minced meat were inoculated or uninoculated with L. monocytogenes and L. innocua and were stored at 4 °C for 18 d. Samples were taken every 3 d, and the development of the bacterial species, pH and water activity ( aw) were monitored. The 100% CO2 atmosphere was the most effective for the inhibition of growth of both species; pH influenced microbial inhibition but low pH values were not the most important factor in the inhibition of Listeria, the direct effect of the CO2 was necessary for that inhibition. Water activity values did not change during storage. None of the gas mixtures were bactericidal. The numbers of L. innocua recovered from all the modified atmos pheres tested were always lower than those of L. monocytogenes.
Note. Occurrence of Listeria spp. in salmon-trout (Onchorhyncus mykiss) and salmon (Salmo salar) / Nota. Presencia de Listeria spp. en trucha asalmonada (Onchorhyncus mykiss) y salmón (Salmo salar)
Authors: Vaz-Velho M. , Duarte G. , Gibbs P.
Published: March 2007

Salmon-trout ( Onchorhyncus mykiss) and salmon ( Salmo salar) are the main raw materials in the cold-smoked fish industry. It is important to prevent the contamination of these ready-to-eat products with Listeria monocytogenes and other ( Listeria spp.) because the temperature used in the cold-smoking process is not sufficient to inactivate these organisms. The presence of Listeria spp. and L. monocytogenes in the cold-smoked salmon and salmon-trout processing chains of three Portuguese factories examined was already confirmed in previous studies. Thus, it was important to ascertain the possible sources of contamination, the raw material being the most important one. All the Portuguese cold-smoking fish factories use fresh salmon-trout from two trout farms in the north of Portugal and Norwegian salmon which arrives by lorry every week under refrigeration, imported always by the same company; 88 samples of salmon and salmon-trout were analysed; 67 environmental samples from the two trout farms were also examined. The overall frequency ( n = 40) of Listeria spp. and L. monocytogenes in salmon was 12 and 0% respectively. The overall frequency (n = 48) of Listeria spp. and L. monocytogenes in salmon-trout was 6.3 and 2.1% respec tively. Listeria was not found in the environmental samples.
Development of perforation-mediated modified atmosphere packaging to preserve fresh fruit and vegetable quality after harvest/Envasado em atmósfera modificada y películas perforadas para preservar la calidad de frutas y verduras frescas después de su cosecha
Authors: Oliveira F.A.R. , Fonseca S.C. , Oliveira J.C. , Brecht J.K. , Chau K.V.
Published: March 2007

The use of perforations as a means of obtaining large size containers suitable for modified atmosphere packaging (MAP) would greatly enhance the applicability of this technology for storage and distribution of fresh and minimally processed products. General concepts of MAP, and advantages and drawbacks of using perforations to achieve it are discussed. Products for which perforated packages can be used are listed. The variables that affect this type of package are presented and the methodology for designing an adequate package is described and illustrated with the case study of shredded cabbage.
Nonthermal electrical methods in food preservation/Métodos eléctricos no térmicos para la conservación de alimentos
Authors: Barbosa-Cánovas G.V. , Góngora-Nieto M.M. , Swanson B.G.
Published: March 2007

Nonthermal methods to preserve foods, such as pulsed electric fields, light pulses, and oscillating magnetic fields, are gaining attention within the food industry and research laboratories. They offer sound alternatives to conventional thermal processes where quality aspects and costs are becoming a concern.
Revisión: El pardeamiento enzimático en frutas y hortalizas mínimamente procesadas Review: Enzymatic browning in minimally processed fruit and vegetables
Authors: Artés F. , Castañer M. , Gil M.I.
Published: March 2007

One of the main problems that reduces shelf-life of minimally processed fruits and vegetables is the enzymatic browning that occurs on the cut surface area. This deterioration has a great visual impact that decreases the commercial quality, the organoleptic acceptance and the nutritional value. This review is an update of the methods to measure the enzymatic browning and the polyphenol oxidase characteristics. Chemical and physical treatments to inhibit or control enzymatic browning are also reviewed. Chemical inhibitors have been classified depending on whether they act on the enzyme, the substrates or the reaction products. To prevent enzymatic browning, physical treatments, par ticularly low O, atmospheres, are considered as an alternative to chemical methods to minimise the enzymatic activity. Edible coatings for preserving quality of minimally processed products, due to restricted oxygen entrance in addition to reduced moisture loss, are also reviewed.
Rheological properties of corn meal dough / Propiedades reológicas de la pasta de harina de maíz
Authors: Lo T. , Moreira R.G. , Castell-Pérez E.
Published: March 2007

The rheological properties of cooked corn meal dough were determined by squeezing flow, steady shear, and dynamic shear rheological methods. Under biaxial extension, the material exhibited strain- thinning behavior and the normal stress difference could be modeled as a function of biaxial strain rate, with a flow behavior index, n, of 0.38-0.52 and the biaxial consistency coefficient, Kb, ranging from 4.63 x 107 to 9.75 x 107 Pa.s". Steady and dynamic shear studies suggest that the dough exhibits shear-thinning behavior at a shear rate range of 1-40 s-1 and more viscous-like characteristics under dynamic conditions (0.5-10 s-1 frequency). Particle size distribution of the corn meal may affect some of the rheological properties ( K b, K, n) of the cooked dough. Further research is necessary to establish correlation between material variation and product quality for improvement of processes such as extrusion, baking or frying.
Unsaponifiable fraction and n-alkane profile of subcutaneous fat from Iberian ham / Fracción insaponificable y perfil de los n-alcanos de la grasa subcutánea del jamón Ibérico
Authors: Tejeda J.F. , Antequera T. , Ruiz J. , Cava R. , Ventanas J. , García C.
Published: March 2007

The unsaponifiable fraction of subcutaneous fat of dry-cured Iberian hams from pigs fed on different systems during the finishing-fattening period and its feasibility as a method for classifying the hams according to the pigs' feeding background are studied. Unsaponifiable fraction and n-alkane content of subcutaneous fat from ten dry cured hams from Iberian x Duroc pigs raised on two different man agement systems ( Montanera, fed extensively on acorns and pasture, and Pienso, fed on a concentrate diet) are analyzed. The proportion of unsaponifiable material and n-alkanes [pentadecane (n-C15), heptadecane (n-C17), octadecane (n-C18), nonadecane (n-C19), eicosane (n-C20) and pentacosane (n-C25)] were higher ( P < 0.05) in hams from pigs raised under extensive conditions than in those from pigs receiving concentrate feeds. The unsaponifiable fraction assay of the fat from dry-cured Iberian hams is a promising technique for classifying hams based on the pigs' feeding background.
Effect of α—tocopheryl acetate supplementation and the extensive feeding of pigs on the volatile aldehydes during the maturation of Iberian ham / Efecto del suplemento con acetato de α—tocoferol y de la alimentación en extensive del cerdo en los aldehídos volátiles durante la maduración del jamón Ibérico
Authors: Cava R. , Ruiz J. , Ventanas J. , Antequera T.
Published: March 2007

The effect of feeding regime—free—range reared on acorn and pasture, or in confinement with and without the incorporation of 100 mg/kg α-tocopheryl acetate to pig mixed feeds—on volatile alde hyde content in Biceps femoris muscle throughout the ripening of Iberian ham was studied. Saturated aldehydes from 4 to 10 carbon chain and two diunsaturated aldehydes, 2,4-nonadienal and 2,4- decadienal, were found in ham samples. Volatile aldehyde evolution was not affected by feeding regime throughout ripening of hams. Volatile aldehyde content and individual aldehydes rose mark edly from Day 0 to Day 210 ( p < 0.05), and afterwards decreased to Day 700 ( p < 0.05). Both α- tocopheryl acetate supplementation and feeding on acorn and pasture significantly decreased the total and individual aldehydes in Biceps femoris samples at Days 0, 210 and 700 ( p < 0.05) in compari son with muscle samples from pigs fed the non-supplemented diet.
Type II Diabetes
Authors: Thobaben Marshelle , Blake Pam
Published: March 2007

Diabetes requires lifelong self- management. Home health care professionals are often an integral part of clients' health care teams, ensuring that they receive quality medical and nursing care. The education of clients about diabetes must be ongoing and applicable to the needs of a diverse population. This article provides a review of the importance of diet, exercise, and other interventions that can help a client with diabetes live a full life with as few complications as possible.