bluuebunny/crossref_metadata_2025 huggingface dataset:
Secondary Agricultural Science as Content and Context for Teaching
Authors: Roberts T. Grady , Ball Anna L.
Published: April 2010

The purpose of this philosophical article was to examine the role of agriculture in agricultural education. This philosophical argument, in many ways, reexamines the very discussions pondered by Dewey and Snedden almost a century ago. In secondary agricultural education classes today, is agriculture the content learned, or the context in which learning occurs? In exploring this issue, theoretical bases and conceptual models for agriculture as content and context are presented. It was concluded that there are theoretical bases for viewing agriculture both as content and context for teaching agriculture at the secondary level. Accordingly, a model is proposed that acknowledges that agriculture provides a rich context in which learning can occur. Today's agricultural educators teach both agricultural content and knowledge from other domains, yielding integrated curriculum. Learning occurs in complex social environments with teacher-to-learner and learner-to-learner interactions. Agricultural education has dual outcomes: a skilled agricultural workforce and successful citizens that are agriculturally literate contributors in a democratic society. The two aforesaid outcomes are not mutually exclusive, and former students (and lifelong learners) may move in and out of gainful employment in the agricultural industry throughout their lifetime.
Issues Facing Urban Agriscience Teachers: A Delphi Study
Authors: Warner Wendy J. , Washburn Shannon G.
Published: April 2010

This national study used the Delphi technique to identify the issues facing urban agriscience teachers. The first round of the study used a questionnaire with one open-ended question to generate responses from the expert panel. In the second round, respondents were asked to rate their level of agreement with 72 issues identified in round one using a Likert-type scale. In round three, participants were asked to indicate their agreement or disagreement with 49 statements retained from round two. Consensus was reached on 17 issues facing agriscience teachers in urban areas which were identified as: challenges presented by the No Child Left Behind legislation; lack of awareness of agriculture by parents, faculty, community and students; lack of parental involvement; budgets and school funding; and time management.
Does a Math-Enhanced Curriculum and Instructional Approach Diminish Students' Attainment of Technical Skills? A Year-Long Experimental Study in Agricultural Power and Technology
Authors: Young R. Brent , Edwards M. Craig , Leising James G.
Published: April 2010

The purpose of this study was to empirically test the posit that students who participated in a contextualized, mathematics-enhanced high school agricultural power and technology (APT) curriculum and aligned instructional approach would not differ significantly (p < .05) in their technical competence from students who participated in the traditional APT curriculum and instruction.This study included teachers and students from 32 high schools in Oklahoma (16 experimental classrooms; 16 control classrooms).Students were enrolled in an APT course during the 2004-2005 school year.The experimental design used was a posttest only control group; unit of analysis was the classroom.One-way analysis of variance (ANOVA) was used to test the study's null hypothesis.The measure of students' technical competence did not reveal results that held statistical significance and supported use of the experimental treatment.
The Problem of Agricultural and Industrial Education for African Americans: A Historical Inquiry
Authors: Croom Dan B. , Alston Antoine
Published: April 2010

The model of agricultural and industrial education for African Americans in the United States was created by Samuel Chapman Armstrong, founder of Hampton Normal and Agricultural Institute. Armstrong developed a paternal approach to educating African Americans and developed the Hampton Institute curriculum with moral education as its base. Booker T. Washington, a protégé of Armstrong, carried the Hampton Model to Tuskegee, Alabama, and made it the basis for the curriculum at the Tuskegee Normal and Industrial Institute. The Hampton Model applied the concepts of moral education and a "learning by doing" approach to instruction. Both Armstrong and Washington were successful in garnering public support and private financial assistance for their respective institutes. The Hampton Model was utilized by a number of schools that sprang up in years after the American Civil War. Hampton and Tuskegee often helped to raise the standard of living for African Americans in the years following the American Civil War, but these advances could not be sustained under the tremendous social pressures associated with race and ethnicity of the 20th century.
An Assessment of Extension Education Curriculum at Land Grant Universities
Authors: Harder Amy , Mashburn Diane , Benge Matt
Published: April 2010

A critical assessment of extension education is needed to ensure there are adequate opportunities for students to study extension education and that the curriculum is relevant to today's Cooperative Extension Service. This descriptive study was conducted to assess extension education curriculum by identifying and comparing the courses being taught at land grant universities with the competency areas in the Ohio State model of extension education. Courses related to extension knowledge, leadership, and management; theories of human development and learning; program planning, implementation, and evaluation; and applied research were most commonly included in the curriculum. The lack of balance in the curriculum and the discrepancies between the Ohio State model and current practice indicate a need for continued discussion about the types of courses that should be included in extension education curriculum.
Identifying Quality Indicators of SAE and FFA: A Delphi Approach
Authors: Jenkins III , Kitchel Tracy
Published: April 2010

The purpose of this study was to determine quality indicators for SAE and FFA according to 36 experts across the United States. This is a part of a larger study looking at all components of the traditional three-circle model. The study utilized the Delphi technique to garner expert opinion about quality indicators in Agricultural Education. For SAE, round two resulted in two of the 46 quality statements reaching consensus. In addition, 17 SAE items were determined not to be quality indicators. Four of the 26 SAE statements in round three reached consensus. Also, for FFA, round two resulted in 13 of the 65 quality FFA statements reaching consensus, with 16 of the 65 FFA items determined not to be quality indicators of FFA. Six of the 36 FFA statements in round three reached consensus. This study is valuable in determining a scientific basis for identifying possible indicators of quality SAE and FFA.
Predicting Agricultural Education Student Teachers' Intention to Enter Teaching
Authors: Roberts T. Grady , Harlin Julie F. , Briers Gary E.
Published: April 2010

The purpose of this study was to explore how the student teaching experience and other variables influenced student teachers' intentions to teach. Data were collected from 80 student teachers at three universities—a land grant/research I institution, a non-land grant/doctoral degree granting institution, and a comprehensive regional institution. Data were collected longitudinally at four points during the student teaching semester. The typical student teacher in this study was a 22-year-old, white, male undergraduate who had been enrolled in agricultural education courses in high school and who had worked full time in agriculture. Intentions to teach did not change during the student teaching experience but did differ by university. The best predictor of a student teacher's intent to teach after student teaching was their intention to teach before student teaching. Differences in intentions to teach were observed at the three universities, and thus university was also predictive of final intent to teach.
Engaging Hispanic Students in Agricultural Education and the FFA: A Three-Year Case Study
Authors: Roberts T. Grady , Hall Jonathan L. , Briers Gary E. , Gill Ernie , Shinn Glen C. , Larke Jr. , Jaure Paul
Published: April 2010

This article describes the outcomes of field-based efforts to increase diversity in agricultural education programs and the FFA. This study focused on three schools in San Antonio, Texas. Guided by Rogers' (2003) theories of diffusion of innovations, a series of six intervention strategies was implemented: (a) provide specific FFA or agricultural education experiences for student opinion leaders; (b) provide specific experiences for parents, alumni, boosters, and school administrators (champions and opinion leaders); (c) provide professional development for teachers (ensure compatibility); (d) introduce new curricula to allow for an expansion of the agricultural education program (trialability); (e) provide access to an on-site project advisor (change agent); and (f) provide project leadership and oversight through a partnership among university faculty members and National FFA staff. Evidence indicated that all three schools increased Hispanic enrollment in their agricultural education program and membership in the FFA. Each school experienced an increase in the number of Hispanic students participating in local, state, and national FFA activities. Additionally, each school increased the total number of local, state, and national FFA activities in which they participated. The three schools established FFA alumni chapters with parents and/or boosters engaged in activities to support students.
A Comparison of Traditional and Self-Paced Instruction: Knowledge Gained in a Food Safety Certification Course
Authors: Sexton Julie S. , Schilling Jennifer K. , Taylor Jan C.
Published: April 2010

The prevention of foodborne illness in childcare centers is a major public health concern. One prevention mechanism is the education of childcare providers. Because of the very diverse population in the childcare profession, the constant turnover rate and the need for high-quality, accessible training, providing this training proves to be an ongoing challenge for many state Extension programs. TummySafe© met this challenge by offering food safety training via two methods. Participants either attended a traditional Extension workshop or experienced the curriculum on a computer of their choosing via CD-ROM. The Mississippi State University Extension Service's 82 county offices coordinated training for childcare providers from April 2005 to June 2006. Traditional participants (n = 829) had higher posttest score means, after adjusting for pretest knowledge, than participants in the self-paced group (n = 796). An ANCOVA revealed a statistically significant difference (F = 268.00, p < .05) favoring the traditional delivery method. Nonetheless, the participants of the self-paced group were highly satisfied with the training and the convenience it offered.
Describing the Cognitive Level of Professor Discourse and Student Cognition in College of Agriculture Class Sessions
Authors: Ewing John C. , Whittington M. Susie
Published: April 2010

The purpose of this study was to describe the cognitive level of professor discourse and student cognition during selected college of agriculture class sessions. Twenty-one undergraduate class sessions were videotaped in 12 professors’ courses. Results were interpreted to show that professors’ discourse was mostly (62%) at the knowledge and comprehension levels of cognition, the lower levels of cognitive thought (Bloom, Engelhart, Furst, Hill, & Krathwohl, 1956). During the 21 class sessions, 1,448 student thoughts were recorded. Forty percent (n = 564) of those thoughts were found to be engaged. Engaged thoughts were then analyzed using Bloom’s Taxonomy (1956). Sixty-two percent of the total 564 engaged thoughts occurred at the knowledge and comprehension levels of cognition. The cognitive levels of professor discourse and student cognition (engaged thoughts categorized and weighted using Bloom’s Taxonomy) were mostly at the two lowest levels of Bloom’s Taxonomy, knowledge and comprehension. Recommendations included professor and student awareness of the cognitive levels at which they teach and think, and further study of relationships between professor and student variables.
Transformational Leadership Research in Agricultural Education: A Synthesis of the Literature
Authors: Greiman Bradley C.
Published: April 2010

Leadership development is viewed as a foundational component of agricultural education and has been associated with the field since the early 20th century. An emerging research topic is leadership style and inquiry that is focused on transformational leadership. In an effort to contribute to the field’s knowledge base in leadership development and to guide a leadership research agenda, a synthesis of literature examined transformational leadership. Premier journals in the field and several affiliated journals published from 1990 to 2008 were selected for analysis. The study concluded that a small but recent number of articles focused on transformational leadership and the majority of research was conducted with extension personnel. Most studies focused on participants from a single state, and almost all of the studies gathered leadership style data through a self-reported procedure. Demographic variables and their relationship to leadership style received the most attention of researchers. Compared to the Multifactor Leadership Questionnaire (MLQ) normative sample, college of agriculture deans, extension personnel, and agricultural education teachers perceived they had higher scores for most leadership factors. Suggestions for future research are presented and draw attention to the potential that this line of inquiry has for a field that embraces leadership development.
Employers' Perceptions of Recent Agricultural Communications Graduates' Workplace Habits and Communication Skills
Authors: Irlbeck Erica Goss , Akers Cindy
Published: April 2010

Agricultural communications programs should frequently review their curriculum to ensure students receive the highest quality of education possible (Akers, 2000). This research is a nationwide look at recent agricultural communications graduates’ employers and/or co-workers. The purpose of this study was to determine which workplace habits and communication skills are satisfactory and which need improvements in the opinion of co-workers or employers. Members of several professional agricultural communications organizations were surveyed (N = 88) in the summer of 2008 with a 34.1% response rate. The study found that employers and co-workers of recent agricultural communications graduates, on average, rated trustworthiness, easy to work with, and reliability as the top workplace habits, while creativity, common sense, and organization need improvement. Photo editing, page layout, and public relations skills received the highest mean communications skills scores, while sales, Web design, and news editing were the communications skills that could use some work.
Effect of Enrollment in Agriscience on Students' Performance in Science on the High School Graduation Test
Authors: Theriot Paul J. , Kotrlik Joe W.
Published: April 2010

This study determined whether enrollment in agriscience education was related to high school students’ science achievement. The results of the mandatory high school graduate exit exams were used to measure science achievement. All test scores from non-special education students were utilized for the study. The comparison of the science achievement of agriscience education students to that of non-agriscience education students revealed that there were significant differences in scores on the science test and the subtests. The effect size for each of these areas was either small or of negligible practical significance. Regression analyses were used to determine if enrollment in agriscience education explained variance in the science scores, after controlling for variance attributed to age, grade level, gender, ethnicity, 504 status, and socioeconomic status. Significant models with moderate or large effect sizes existed that explained a portion of variance in scores on the science tests and subtests. However, after controlling for the six variables listed above, the contribution of enrollment in agriscience education to the science test and subtest scores was negligible. This result is positive evidence for the value of agriscience education since agriscience education students acquire knowledge, skills, and experiences substantially beyond the academic content in the courses.
Examining iPod Use by Texas Agricultural Science and Technology Teachers
Authors: Murphrey Theresa Pesl , Miller Kimberly A. , Roberts T. Grady
Published: April 2010

The purpose of this study was to establish baseline data regarding the adoption of iPods and similar technologies by agricultural science and technology teachers. The population consisted of all agricultural science and technology teachers in Texas. A sample of 310 was randomly drawn from the population. Study findings reveal that while agricultural science and technology teachers have knowledge of iPods, mp3 players and related technologies, there is little support for them to actually create their own podcasts, use them in the classroom, or promote them for student use. It was concluded that teachers weregenerally “late adopters” or “laggards,” while students were “innovators” or “early adopters.” Both teachers and students alike have access to computers and Internet connections, with a large number of teachers reporting that students own iPods or mp3 players which could be utilized for academics. Teachers reported strong interest in pre-produced curricula and FFA materials, particularly for training materials for career development events, which could be used on iPods or mp3 players. Recommendations for encouraging teacher adoption and use of iPods and similar technologies were provided.
Agricultural Science and Technology Teachers' Perceptions of iPod and MP3 Technology Integration Into Curricular and Cocurricular Activities
Authors: Murphrey Theresa Pesl , Miller Kimberly A. , Roberts T. Grady
Published: April 2010

The purpose of this study was to describe agricultural science and technology teachers’ reaction to iPod and mp3 technology use and potential use in both curricular and cocurricular activities. A total of 112 unique respondents provided written responses to open-ended questions. Study findings reveal that agricultural science and technology teachers see iPod and mp3 technologies as beneficial, yet some teachers find this technology to be unusable due to campus restrictions and student abuse. Teachers provided a multitude of possible applications for iPod and mp3 technologies: contest preparation and team training, general classroom enhancement, specific classroom content areas that could benefit, applications for absence/make-up work and homework support, use with substitute teachers, assisting special populations, use for organization of content, and additional creative applications. Overall, teacher reaction to the use of iPod and mp3 technologies was positive and yielded findings that can be useful to teachers, researchers, and providers of educational content. This article strives to give voice to the individual teacher.
A Comparison of First and Fifth Year Agriculture Teachers on Personal Teaching Efficacy, General Teaching Efficacy and Content Efficacy
Authors: Burris Scott , McLaughlin E. Katy , McCulloch Abigail , Brashears Todd , Fraze Steve
Published: April 2010

The purpose of this study was to compare first and fifth year agriculture teachers’ on general teaching efficacy, personal teaching efficacy, and content efficacy. Teacher efficacy has been defined as a two dimensional construct composed of personal teaching and general teaching efficacy. Personal teaching efficacy involves a teacher’s evaluation of their own capability to bring about student learning. General teaching efficacy reflects the degree a teacher believes other educators can control the learning environment despite influences such as family background, intelligence quotient (IQ) and school conditions (Gibson & Dembo, 1984). Content efficacy is the level of confidence an agriculture teacher possesses in agribusiness and economics, plant and soil science, animal science, agricultural mechanics and technology, and natural resources and environmental science. The sample consisted of first and fifth year agriculture teachers in Texas during the 2006–07 school year. A total of 129 first year teachers and 68 fifth year teachers were identified and 141 teachers responded yielding a 71% response rate. Personal teaching and general teaching efficacy were measured by the short form of the teacher efficacy scale (Woolfolk & Hoy, 1990). A researcher developed instrument was used to measure content efficacy.
Factors Influencing Relational Satisfaction Within An Agricultural Education Mentoring Program
Authors: Lambert Misty D. , Smith Amy R. , Ulmer Jonathan D.
Published: April 2010

Agricultural education is facing a teacher shortage. As a result, many states have implemented a mentoring program to help retain early career teachers. One of the challenges facing mentoring programs is the process of creating successful pairs. The purpose of this study was to determine if Mind Styles™ of mentors and protégés influenced satisfaction with the mentoring relationship. The study also describes demographics, Mind Styles™, and relational satisfaction scores of both mentors and protégés. Data were collected using the Gregorc Style Delineator™ as well as the Mentoring Relationship Questionnaire. The subjects for this study were all mentors and first year protégés in Missouri. The average age of mentors was 40.83 with the average protégé being 25.28 years of age. The mentor group was 80% male while protégés were 69% male. The group was largely Concrete Sequential, but all styles did appear at least once. Differences in relational satisfaction based on Mind Style™ combinations were found for three different combinations. A large effect size was found for Concrete Sequential mentors paired with Abstract Random protégés, indicating a difference in satisfaction.
Preparing for, Conducting and Evaluating Workshops for Agricultural Technical School Instructors in Egypt
Authors: Thoron Andrew C. , Barrick R. Kirby , Roberts T. Grady , Gunderson Michael A. , Samy Mohamed M.
Published: April 2010

The Agricultural Technical Schools (ATS) of Egypt were designed to prepare skilled workers for the agricultural economy. A project funded by USAID through the Midwest Universities Consortium for International Activities (MUCIA) was designed to prepare ATS instructors for incorporating supervised agricultural internships and agribusiness decision–making skills into their curricula. Workshops were presented, with assistance from university faculty in Egypt, on topics including planning, conducting and evaluating internships, and on selected agribusiness competencies that were relevant to ATS programs. Workshop participants rated the workshops and materials very highly. The ATS instructors also indicated that their competency in teaching the topics had increased as a result of the workshops. The instructors indicated other topics that future workshops could address. The researchers identified a series of lessons learned about conducting workshops in a foreign country and offered recommendations to assist other U.S. faculty in getting involved in international development projects.
Agriculture Teacher Perceptions of Preparation to Integrate Science and Their Current Use of Inquiry Based Learning
Authors: Washburn Shannon G. , Myers Brian E.
Published: April 2010

The purpose of this study was to determine the perceived competence of agricultural education teachers in integrating science and use of inquiry based teaching techniques in agricultural education programs. Objectives included describing agriculture teacher perceptions of teacher preparation program needs based upon their personal competence to integrate science into the agricultural education curriculum, identifying factors influencing agriculture teachers’ current and planned levels of science integration in the agricultural education programs, and describing the use of inquiry based teaching techniques in agricultural education programs. The population for the study was all secondary agriculture teachers in Florida. A total of 217 teachers participated for a 61.1% response. It was found that although agriculture teachers feel prepared to integrate science, they also believe more should be done to prepare future teachers to do so. Furthermore, nearly three fourths of the participants intended to increase their level of science integration. Finally, teachers reported using teacher–oriented inquiry strategies nearly three times per week, while they reported using student–oriented inquiry nearly once per month.
Efficient air traffic conflict resolution by minimizing the number of affected aircraft
Authors: Idan M. , Iosilevskii G. , Ben‐Yishay L.
Published: April 2010

The paper addresses local conflict resolution in dense air traffic scenarios. Currently, air traffic can reach a few thousands of aircraft airborne simultaneously over Europe or U.S., with predictions that it will grow significantly during the next two decades. All this traffic is expected to be organized well in advance and updated before take‐off, providing each aircraft a conflict‐free flight plan. Deviations from this plan, caused by the difference between the actual and predicted weather, equipment malfunctions, operational or airport delays, etc., may create in‐flight conflicts that will have to be resolved in a matter of minutes. Since real‐time re‐organization of the entire traffic is impractical due to high computational complexity, local re‐planning, affecting only the aircraft involved in the conflicts, is in order. In this paper we suggest a rapid local re‐planning algorithm. Its efficiency is attained by re‐computing new trajectories only for a minimal number of aircraft that resolves the conflicts. Finding optimal trajectories only for those aircraft not only reduces the computational effort, but also reduces average pilot workload. Copyright © 2010 John Wiley & Sons, Ltd.
How Noniridescent Colors Are Generated by Quasi‐ordered Structures of Bird Feathers
Authors: Noh Heeso , Liew Seng Fatt , Saranathan Vinodkumar , Mochrie Simon G. J. , Prum Richard O. , Dufresne Eric R. , Cao Hui
Published: April 2010

We investigate the mechanism of structural coloration by quasi‐ordered nanostructures in bird feather barbs. Small‐angle X‐ray scattering (SAXS) data reveal the structures are isotropic and have short‐range order on length scales comparable to optical wavelengths. We perform angle‐resolved reflection and scattering spectrometry to fully characterize the colors under directional and omni‐directional illumination of white light. Under directional lighting, the colors change with the angle between the directions of illumination and observation. The angular dispersion of the primary peaks in the scattering/reflection spectra can be well explained by constructive interference of light that is scattered only once in the quasi‐ordered structures. Using the Fourier power spectra of structure from the SAXS data we calculate optical scattering spectra and explain why the light scattering peak is the highest in the backscattering direction. Under omni‐directional lighting, colors from the quasi‐ordered structures are invariant with the viewing angle. The non‐iridescent coloration results from the isotropic nature of structures instead of strong backscattering.
Evidence for genes on chromosome 2 contributing to alcohol dependence with conduct disorder and suicide attempts
Authors: Dick Danielle M. , Meyers Jacquelyn , Aliev Fazil , Nurnberger John , Kramer John , Kuperman Sam , Porjesz Bernice , Tischfield Jay , Edenberg Howard J. , Foroud Tatiana , Schuckit Marc , Goate Alison , Hesselbrock Victor , Bierut Laura
Published: April 2010

Twin studies provide strong evidence that there is a shared genetic liability that predisposes to a number of different psychiatric outcomes related to behavioral disinhibition. Further, alcohol dependence comorbid with other disinhibitory disorders is particularly heritable. Chromosome 2p14‐2q14.3 has been linked to multiple psychiatric conditions related to behavioral undercontrol. In the Collaborative Study on the Genetics of Alcoholism (COGA), we previously reported linkage to this region with alcohol dependence (AD), suicide attempts (SUI), and conduct disorder (CD). In this study, we follow‐up on these previous reports of linkage by combining the phenotypes in analyses that jointly consider the presence of multiple conditions. Linkage analyses of the combined phenotype of AD with CD or SUI results in a maximum LOD score of 5.4 in this region. In addition to this primary linkage peak, independent samples have reported linkage to other alcohol‐related phenotypes across chromosome 2. Accordingly, we followed‐up these linkage signals by testing for association with SNPs across chromosome 2 in a case–control sample, in which a subset of the cases consisted of alcohol‐dependent probands from the linkage sample. We find evidence of association with the combined AD with CD or SUI phenotype, with 23 genes surviving permutation testing. The number of associated genes across the chromosome may explain the persistent linkage findings reported on chromosome 2 across a number of independent studies of alcohol and disinhibitory phenotypes. Further, none of the genes were located directly under the primary COGA linkage peak, which has implications for association tests following‐up linkage peaks. © 2010 Wiley‐Liss, Inc.
Goldnanopartikel in Biologie und Medizin
Authors: Giljohann David A. , Seferos Dwight S. , Daniel Weston L. , Massich Matthew D. , Patel Pinal C. , Mirkin Chad A.
Published: April 2010

Goldkolloide werden in Chemie, Biologie, Technik und Medizin häufig eingesetzt. Heute kann man diese Materialien reproduzierbar herstellen, mit einer scheinbar unbegrenzten Zahl an funktionellen Gruppen chemisch modifizieren und – in bestimmten Fällen – bis hinab zur Ebene einzelner Atome charakterisieren. Dieser Aufsatz behandelt neuere Entwicklungen hinsichtlich Synthese und Biokonjugation von Goldnanokonjugaten sowie deren Verwendung in Zellen. Es gibt heute viele Beispiele für hochempfindliche und selektive Assays auf der Basis von Goldkonjugaten. In den letzten Jahren war der Fokus auf den Einsatz solcher Materialien in der Therapie gerichtet. Strukturen, die als genregulierende Agentien, Wirkstofftransporter, Bildgebungsagentien und lichtempfindliche Therapeutika fungieren, wurden entwickelt und in Verbindung mit Zellen und vielen schwächenden Krankheiten erforscht. Diese Strukturen wurden nicht einfach als Alternativen zu molekularen Systemen gewählt, sondern weil ihre neuen physikalischen und chemischen Eigenschaften ihnen in zellulären und medizinischen Anwendungen erhebliche Vorteile verschaffen.
Gold Nanoparticles for Biology and Medicine
Authors: Giljohann David A. , Seferos Dwight S. , Daniel Weston L. , Massich Matthew D. , Patel Pinal C. , Mirkin Chad A.
Published: April 2010

Gold colloids have fascinated scientists for over a century and are now heavily utilized in chemistry, biology, engineering, and medicine. Today these materials can be synthesized reproducibly, modified with seemingly limitless chemical functional groups, and, in certain cases, characterized with atomic‐level precision. This Review highlights recent advances in the synthesis, bioconjugation, and cellular uses of gold nanoconjugates. There are now many examples of highly sensitive and selective assays based upon gold nanoconjugates. In recent years, focus has turned to therapeutic possibilities for such materials. Structures which behave as gene‐regulating agents, drug carriers, imaging agents, and photoresponsive therapeutics have been developed and studied in the context of cells and many debilitating diseases. These structures are not simply chosen as alternatives to molecule‐based systems, but rather for their new physical and chemical properties, which confer substantive advantages in cellular and medical applications.
Preliminary analysis on dynamic route choice behavior: Using probe‐vehicle data
Authors: Morikawa Taka , Miwa Tomio
Published: April 2010

Dynamic traffic assignment models have been attracting increasing attention with the progress of traffic management policies based on information technology. These dynamic estimation tools, however, just apply static route choice models either at only origin node or at every arrival node. This paper aims at providing some knowledge on drivers' dynamic route choice behavior using probe‐vehicle data. The results of analyses show that route choice behavior relates to the distance from driver's position to the destination and that dynamic route choice behavior is modeled better by considering decision process during the trip.
Drivers' route choice and learning mechanism under bounded information environment
Authors: Do Myungsik , Ryu Sikyun , Lee Seungjae
Published: April 2010

In this paper, we propose the theory of Rational Beliefs as the model of expectations that extends the theory of rational expectations to the postulated environments. Under the rational beliefs paradigm, drivers do not have structural knowledge of traffic conditions and they choose their routes based only on personal experiences and decision‐making rules. We found that if drivers have different decision‐making rules and experiences, then they form different beliefs of traffic conditions (e.g. average travel time) even though they have the same public information and use the same routes. Under the rational beliefs model, drivers are not motivated to renew their beliefs because the beliefs are compatible with their experiences. Therefore, the heterogeneity of beliefs does not disappear even though they have long‐term learning. In order to investigate how drivers form their beliefs of traffic conditions under bounded information environments, numerical experiment is carried out.
Equilibrium analysis of the scheduling of tours in congested networks
Authors: Heydecker Benjamin , Polak John
Published: April 2010

In this paper, we develop a model of travel in tours that joins several locations by travel through a congested network. We develop a microscopic analysis in continuous time of individual benefits obtained by spending time at each of the locations and costs incurred through travel between them. This is combined with a continuous time macroscopic equilibrium model of travel during congested peak periods to show how individuals' travel choices are influenced by the congestion that result from corresponding choices made by others. We show how different travellers can achieve identical net utilities by making different combinations of choices within the equilibrium. The resulting model can be used to investigate the effect on travel behaviour and individual utility of various transport interventions, and we illustrate this by considering the effect of a peak‐period charge that eliminates congestion.
The optimal dispatching of taxis under congestion: A rolling horizon approach
Authors: Wong K. I. , Bell Michael G. H.
Published: April 2010

Taxis make an important contribution to transport in many parts of the world, offering demand‐responsive, door‐to‐door transport. In larger cities, taxis may be hailed on‐street or taken from taxi ranks. Elsewhere, taxis are usually ordered by phone. The objective of a taxi dispatcher is to maximize the efficiency of fleet utilization. While the spatial and temporal distribution of taxi requests has in general a high degree of predictability, real time traffic congestion information can be collected and disseminated to taxis by communication technologies. The efficiency of taxi dispatching may be significantly improved through the anticipation of future requests and traffic conditions. A rolling horizon approach to the optimisation of taxi dispatching is formulated, which takes the stochastic and dynamic nature of the problem into account. Numerical experiments are presented to illustrate the performances of the heuristics, taking the time dependency of travel times and passenger arrivals into account.
Liposomes destabilize tRNA during heat stress
Authors: Suga Keishi , Umakoshi Hiroshi , Tomita Hibiki , Tanabe Tomoyuki , Shimanouchi Toshinori , Kuboi Ryoichi
Published: April 2010

Biomembranes play an important role in cellular response to heat stress. In this study, we focus on the interaction between liposomes and tRNA. Upon heat treatment we determined circular dichroism spectra of tRNA in presence of liposomes prepared from POPC (1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine) and cholesterol (Ch). To compare thermal stability, midpoint temperature (Tm) of tRNA was calculated from normalized θ208. Addition of POPC/Ch liposomes decreased the Tm value of tRNA from 48°C to 38°C. We conclude that POPC/Ch liposomes interact with tRNA and destabilize its conformation under heat stress.
A theoretical method to improve and optimize the design of bioartificial livers
Authors: Davidson Adam J. , Ellis Marianne J. , Chaudhuri Julian B.
Published: April 2010

Bioartificial livers (BALs) are a potentially effective countermeasure against liver failure, particularly in cases of acute or fulminant liver failure. It is hoped these devices can sustain a patient's liver function until recovery or transplant. However, no large‐scale clinical trial has yet proven that BALs are particularly effective and evidently design issues remain to be addressed. One aspect of BAL design that must be considered is the mass transfer of adequate oxygen to the hepatocytes within the device. We present here a mathematical modeling approach to oxygen mass transport in a BAL. A mathematical model based upon Krogh cylinders is outlined to describe a diffusion‐limited hollow fiber bioreactor. In addition, operating constraints are defined on the system—cells should not experience hypoxia and the cell population should be of adequate size. By combining modeling results with these operating constraints and presenting the results graphically, “operating region” charts can be constructed for the hollow fiber BAL (HF‐BAL). The effects of varying various operating parameters on the BAL are then established. It is found that smaller radii and short, thin walled fibers are generally advantageous while cell populations in excess of 10 billion could be supported in the BAL with a plasma flow rate of 200 mL/min. For fibers of intermediate length and lumen radius, the minimum number of fibers required to produce a viable design ranges approximately from 7,000–10,000. In theory, this may be enough to support patients with failing livers. Biotechnol. Bioeng. 2010;106: 980–988. © 2010 Wiley Periodicals, Inc.
Konflikte und Konfliktlösung in den Staaten sozialer Insekten. Zwischen Superorganismus und Polizeistaat
Authors: Heinze Jürgen
Published: April 2010

Die Staaten sozialer Insekten galten lange als harmonische, konfliktfreie Superorganismen, in denen alle Individuen selbstlos zusammenarbeiten, um den Fortpflanzungserfolg des Staats als Ganzes zu maximieren. Diese Vorstellung hat sich in den vergangenen Jahren sehr stark gewandelt. Tatsächlich können Individuen egoistisch ihre Einzelinteressen verfolgen, was dem gesamten Staat schaden kann. Die Integrität von Insektenstaaten wird dadurch gewährleistet, dass egoistische Reproduktion durch Arbeiterinnen weitgehend unterbunden wird, sei es durch direkte Attacken von Seiten der Königin, die Etablierung von Dominanzhierarchien oder gegenseitige Überwachung und Bestrafung. Eine genaue Analyse der Vorgänge im Insektenstaat hilft zu verstehen, wie Kooperation zwischen an sich egoistischen Einzelindividuen aufrecht erhalten werden kann.
Redox‐Regulation. Ein Netzwerk zur flexiblen Adaptation von Stoffwechsel und Entwicklung bei Pflanzen
Authors: Scheibe Renate
Published: April 2010

Pflanzen benötigen Faktoren aus der Umwelt für ihr photoautotrophes Wachstum, jedoch sind sie durch ihre sessile Lebensweise Abweichungen vom Optimum ausgeliefert. Anpassung an sehr unterschiedliche Bedingungen ist ihnen aber möglich, da sie durch entsprechende Veränderung ihrer Reaktionsnorm eine hohe phänotypische Plastizität aufweisen. Alle Informationen werden integriert und über ein hochflexibles Netzwerk weitergeleitet und realisiert. Die Reaktionen der Pflanzen spielen sich auf allen Regulationsebenen ab und umfassen sehr schnelle biophysikalische und biochemische Prozesse (im Sekunden‐ und Minutenbereich) sowie mittel‐ und langfristige Reaktionen, die sich nach Stunden (Genexpression) oder erst nach Tagen (Wachstum) auswirken. In allen Bereichen spielen Redox‐Prozesse eine bedeutende Rolle. Eine Abweichung von der Redox‐Homöostase dient einerseits als Signal, andererseits müssen zu große Ungleichgewichte abgepuffert werden, um Schaden zu vermeiden.
Pinguine – Überlebenskünstler in der Antarktis. Klimawandel
Authors: Kostrzewa Achim
Published: April 2010

Die lokalen und regionalen ökologischen Bedingungen werden die Zukunft der einzelnen Pinguinarten im Bereich der Antarktischen Halbinsel bestimmen. Veränderungen des Eisregimes, der Wassertemperatur und Salinität beeinflussen die Primärproduktion und damit die gesamten Nahrungsnetze in den Südpolargebieten nachhaltig. Mit der Erwärmung wandern Tiere weiter polwärts. Doch unser Wissen über die Seevogelbestände ist begrenzt: Je weiter polwärts eine Art vorkommt, wie der Kaiserpinguin oder die südlichsten Adeliekolonien, desto weniger gesicherte Daten sind vorhanden.
Otto Kleinschmidt – Pionier der Vogelkunde und des Artbegriffes
Authors: Irsch Wilhelm
Published: April 2010

Der Pfarrer Otto Kleinschmidt war nicht nur naturwissenschaftlich, sondern auch musisch begabt: Seine in Figur, Haltung, Stellung, Farbgebung und Zeichnung hervorragenden Bilder begeisterten die Leser von Büchern wie beispielsweise den “Singvögeln der Heimat” (1911, mit 12 Auflagen bis 1963). Seine “Formenkreislehre” polarisierte Gegner und Anhänger gleichermaßen.
Xanthomonas: Die Hacker unter den Pflanzenbakterien
Authors: Brennicke Axel
Published: April 2010

Im Krieg zwischen Lebewesen und ihren Schmarotzern werden alle Register gezogen. Viele Bakterien injizieren spezielle Proteine in Pflanzenzellen, um deren Gene für ihre eigenen Zwecke einzusetzen. Jetzt fanden Wissenschaftler an der Universität Halle heraus, wie die Proteine aus Bakterien die genetischen Schalter in der Pflanzenzelle erkennen. Nach diesem Vorbild lassen sich künstliche Proteine konstruieren, die für nützliche Veränderungen an Kulturpflanzen und anderen Organismen gezielt eingesetzt werden können.
Mega‐Rolle für microRNAs
Authors: Kronberg Inge
Published: April 2010

Embryonale Stammzellen entstehen wie alle Körperzellen aus der Zygote, haben aber bemerkenswerte Fähigkeiten: Sie können sich beliebig oft teilen und erneuern sich dabei selbst oder differenzieren sich schrittweise weiter zu funktionsfähigen Körperzellen (Pluripotenz). Die Entwicklungsrichtung wird von winzigen RNA‐Abschnitten (microRNAs) beeinflusst, die sogar reife, ausdifferenzierte Körperzellen zurück in den pluripotenten Zustand bringen können. Diese Reprogrammierung verspricht vielfältige Möglichkeiten in der regenerativen Medizin und anderen stammzellbasierten Forschungsrichtungen.
Ein Magnetometer im Schnabel aller Vögel?
Authors: Fleissner Gerta , Fleissner Günther , Falkenberg Gerald
Published: April 2010

Eisenhaltige kurze Nervenäste im Oberschnabel von verschiedenen Vogelarten erfüllen alle strukturellen und biophysikalischen Voraussetzungen eines Magnetfeldrezeptors. Die einheitliche Form der Dendriten und ihre Anordnung in der Schnabelhaut lassen auf einen ursprünglichen Mechanismus der Vögel schließen, der als Basis für eine Magnetkarte bei variablen Aufgaben der Orientierung genutzt werden kann: beim Vogelzug über weite Strecken, beim Heimfinden von unterschiedlichen Plätzen in der weiteren Umgebung des Heimatortes oder auch beim Herumstreifen in der nächsten Umgebung des Nistplatzes.
Western‐Blot Teil 1: Die Blotting‐Technik
Authors: Schrödel Andrea
Published: April 2010

Das Verfahren des Western‐Blots wird im Bereich der Proteinbiochemie für den Nachweis von bestimmten Proteinen oder Protein‐Veränderungen (beispielsweise Phosphorylierung) durchgeführt und stellt in der Medizin ein wichtiges Werkzeug für die Diagnostik von Infektionskrankheiten (Nachweis von Antikörpern im Serum) dar. Hierbei werden Proteine im SDS‐Polyacrylamidgel aufgetrennt, auf eine Membran transferiert und in einer antikörperabhängigen Reaktion durch den Umsatz bestimmter Substrate nachgewiesen.
A new RF and Microwave Engineering course enriched with advanced technologies
Authors: Aydin Elif , Cagiltay Nergiz
Published: April 2010

In this study, a curriculum model including recent developments and technologies in the Radio Frequency (RF) and Microwave Engineering field by using a blended approach is proposed. This study covers the description of the content of theoretical and hands on applications, the integration model of the technological tools into the proposed curriculum, and the instructional approaches used in the new course design. The main goal of the course is to prepare students for future professional careers in RF and Microwave Engineering by supporting them with new instructional technologies. The secondary goal of the course is to better prepare the students for the sequence of senior courses in the Electrical and Electronics Engineering program of Atilim University. The course is structured with a balance between theory and laboratory, including remote and in lab measurement experiments as well as modeling and designing microwave components by means of computer tools and design fabrication. The newly designed course is implemented at the Atilim University. The study also reports the first semester implementation. © 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 20: 634–645, 2012
Striving to be ‘good’ mothers: abused women's experiences of mothering
Authors: Lapierre Simon
Published: April 2010

So far, limited work has focused on women's experiences of mothering in the context of domestic violence. This article presents the findings of a study that investigated women's experiences of mothering in the context of domestic violence and, while it accounts for the difficulties and challenges these women face, it emphasises their desire to be ‘good’ mothers and the strategies they develop in order to achieve ‘good’ mothering. The findings demonstrate that abused women typically strive to be ‘good’ mothers, which requires them to put their children first and to protect and care for them. The recognition of these strategies provides ground to question current professional practices and to develop interventions that will best support women and children living with domestic violence. Copyright © 2010 John Wiley & Sons, Ltd.
Strategies for the Inhibition of Protein Aggregation in Human Diseases
Authors: Bartolini Manuela , Andrisano Vincenza
Published: April 2010

Protein misfolding and aggregation has been related to several human disorders, generally termed protein aggregation diseases. These diseases include neurodegenerative disorders such as Alzheimer's, Parkinson's, and Huntington's diseases and peripheral disorders such as systemic amyloidosis and type 2 diabetes. The complexity of the aggregation processes and the intertwined events account for the fact that no effective disease‐modifying treatments for these disorders are currently available. Nevertheless, in‐depth research into the aggregation processes has recently yielded major insights into some key mechanisms of aggregation‐mediated cell toxicity, offering new targets for drug development. In addition, recent findings in the field have identified similar features, revealing the possibility of shared mechanisms and hence potential common approaches for intervention. This review aims to give an overview of potential strategies for tackling protein aggregation and its associated toxicity, focusing on protein aggregation in human disease.