bluuebunny/crossref_metadata_2025 huggingface dataset:
Stabilization of the Actomyosin Ring Enables Spermatocyte Cytokinesis in Drosophila
Authors: Goldbach Philip , Wong Raymond , Beise Nolan , Sarpal Ritu , Trimble William S. , Brill Julie A.
Published: March 2010

The scaffolding protein anillin is required for completion of cytokinesis. Anillin binds filamentous (F) actin, nonmuscle myosin II, and septins and in cell culture models has been shown to restrict actomyosin contractility to the cleavage furrow. Whether anillin also serves this function during the incomplete cytokinesis that occurs in developing germ cells has remained unclear. Here, we show that anillin is required for cytokinesis in dividing Drosophila melanogaster spermatocytes and that anillin, septins, and myosin II stably associate with the cleavage furrow in wild-type cells. Anillin is necessary for recruitment of septins to the cleavage furrow and for maintenance of F-actin and myosin II at the equator in late stages of cytokinesis. Remarkably, expression of DE-cadherin suppresses the cytokinesis defect of anillin-depleted spermatocytes. DE-cadherin recruits β-catenin (armadillo) and α-catenin to the cleavage furrow and stabilizes F-actin at the equator. Similarly, E-cadherin expression suppresses the cytokinesis defect caused by anillin knockdown in mouse L-fibroblast cells. Our results show that the anillin-septin and cadherin–catenin complexes can serve as alternative cassettes to promote tight physical coupling of F-actin and myosin II to the cleavage furrow and successful completion of cytokinesis.
HSP90 Protein Stabilizes Unloaded Argonaute Complexes and Microscopic P-bodies in Human Cells
Authors: Johnston Michael , Geoffroy Marie-Claude , Sobala Andrew , Hay Ron , Hutvagner Gyorgy
Published: March 2010

Key components of the miRNA-mediated gene regulation pathway are localized in cytoplasmic processing bodies (P-bodies). Mounting evidence suggests that the presence of microscopic P-bodies are not always required for miRNA-mediated gene regulation. Here we have shown that geldanamycin, a well-characterized HSP90 inhibitor, abolishes P-bodies and significantly reduces Argonaute and GW182 protein levels but does not affect the miRNA level and the efficiency of miRNA-mediated gene repression; however, it significantly impairs siRNA loading and the efficacy of exogenous siRNA. Our data suggests that HSP90 protein chaperones Argonautes before binding RNA and may facilitate efficient loading of small RNA.
Understanding International Trade in Agricultural Products: One Hundred Years of Contributions by Agricultural Economists
Authors: Josling Tim , Anderson Kym , Schmitz Andrew , Tangermann Stefan
Published: March 2010

The study of international trade in agricultural products has developed rapidly over the past fifty years. In the 1960s the disarray in world agriculture caused by domestic price support policies became the focus of analytical studies. There followed attempts to measure the distortions caused by policies also in developing countries and to model their impact on world agricultural markets. Tools were advanced to explain the trends and variations in world prices and the implications of market imperfections. Challenges for the future include analyzing trade based on consumer preferences for certain production methods and understanding the impact of climate change mitigation and adaptation on trade.
Environmental Economics: How Agricultural Economists Helped Advance the Field
Authors: Kling Catherine L. , Segerson Kathleen , Shogren Jason F.
Published: March 2010

In this essay we examine the coevolution and cross‐fertilization of environmental and agricultural economics over the past century. We discuss the key role that agricultural economists have played in the intellectual development of environmental economics. We focus on three primary contributions: incentive design, nonmarket valuation, and joint determination. The nature of these contributions is illustrated using specific examples from the literature. Agricultural economists’ tendency to focus on applied problems has enriched and broadened both the academic debates and the policy advice provided by economists.
Outcome After Percutaneous Endoscopic Gastrostomy in Children and Young Adults
Authors: Fortunato John E , Troy April L , Cuffari Carmen , Davis J Erin , Loza Matthew J , Oliva‐Hemker Maria , Schwarz Kathleen B
Published: March 2010

Background and Objectives:

Factors predicting outcome after percutaneous endoscopic gastrostomy (PEG) in large pediatric cohorts are not well defined. We hypothesized that definable preoperative clinical factors predict the need for further intervention to provide enteral access after PEG. Our aim was to identify factors associated with PEG outcome.

Materials and Methods:

A retrospective review of 760 (407 boys and 353 girls) patients was performed after PEG at the Johns Hopkins Children's Center from 1994 to 2005. Logistic or multiple linear regression was used to analyze indication; diagnosis; age; prematurity; neurological impairment; weight‐for‐age z scores; modified barium swallow; postoperative complications; need for fundoplication (FP), gastrojejunal tube, or jejunostomy; and length of hospital stay.

Results:

The median age was 1 year (range 0–26 years). The most common indications given for PEG were failure to thrive (n = 373) and dysphagia (n = 27). Postoperative FP, gastrojejunal tube, or jejunostomy were performed in 66 (10%), 24 (4%), and 9 (1%) patients, respectively. Preoperative report indicated that dysphagia and direct aspiration on modified barium swallow was strongly associated with patients undergoing FP after PEG, 10.6% of patients (P = 0.008, odds ratio 2.4) and 11.2% of patients (P = 0.013, odds ratio 2.8), respectively. Younger preoperative age was also associated with the need for FP (P = 0.0006; median age of 5.8 vs 14 months). Patients with preoperative dysphagia had a longer median length of hospital stay: 8 versus 3 days (P < 0.00001). Patients with neurological impairment demonstrated greater weight gain than neurologically normal patients after PEG (P = 0.04). Minor postoperative complications (most commonly wound infection) were observed in 4% (27/747) of children before hospital discharge from PEG and in 20% of children (138/682) after discharge. There were only 2 major complications (gastric separation and gastrocolonic fistula.). There were no fatalities.

Conclusions:

Preoperative diagnosis, indication, prematurity, and neurological impairment did not influence postoperative complications.
Costs and benefits of multi-male associations in redfronted lemurs (
Eulemur fulvus rufus
)
Authors: Port Markus , Johnstone Rufus A. , Kappeler Peter M.
Published: March 2010

The evolution of group-living has fascinated but also puzzled researchers from the inception of behavioural ecology. We use a simple optimality approach to examine some of the costs and benefits of group-living in redfronted lemurs (
Eulemur fulvus rufus
). We show that dominant males profit from accepting subordinates within their groups, as the latter significantly decrease the likelihood that the group is taken over by intruders. This benefit is large enough to outweigh the costs of reproductive competition and may constitute the driving force behind the evolution of multi-male associations in this species.
Allelic variation in colonization factor CS6 of enterotoxigenic Escherichia coli isolated from patients with acute diarrhoea and controls
Authors: Sabui Subrata , Ghosal Abhisek , Dutta Sanjucta , Ghosh Avishek , Ramamurthy T. , Nataro James P. , Hamabata T. , Chatterjee Nabendu Sekhar
Published: March 2010

Colonization factor antigens (CFAs) are important virulence factors in enterotoxigenicEscherichia coli(ETEC). Using a multiplex PCR and RT-PCR, this study tested the presence of common colonization factor-encoding genes and their expression in 50 ETEC strains isolated from stool specimens. The samples were from patients (children) with acute diarrhoea (cases) admitted to the Infectious Disease Hospital (Kolkata, India) and from normal children (controls) under 5 years of age from the community. The results indicated that coli surface antigen 6 (CS6) was the most prevalent CFA (78 %) expressed by these ETEC strains. Sequence analysis of both of the CS6 structural genes, i.e.cssAandcssB, in different ETEC isolates revealed the presence of point mutations in a systematic fashion. Based on the analysis of these variations, it was found that CssA had three alleles and CssB had two. Based on the allelic variations, subtyping of CS6 into AIBI, AIIBII, AIIIBI, AIBII and AIIIBII is proposed. The point mutations in the different alleles were reflected in a partial alteration in the secondary structure of both subunits, as determined by computational analysis. The functional significance of these changes was confirmed with cellular binding studies in Caco-2 cells with representative ETEC isolates. CS6 with AI or AIII allelic subtypes showed a higher binding capacity than AII, whereas BI showed stronger binding than BII. The AII and BII alleles were mostly detected in controls rather than in cases. The antibody specificity of BI and BII also varied due to alteration of the amino acids. Thus, CS6 variants are formed as a result of different allelic combinations of CssA and CssB, and these changes at the functional level might be important in the development of an effective ETEC vaccine.
Dynamic Nucleocytoplasmic Shuttling of an Arabidopsis SR Splicing Factor: Role of the RNA-Binding Domains
Authors: Rausin Glwadys , Tillemans Vinciane , Stankovic Nancy , Hanikenne Marc , Motte Patrick
Published: March 2010

Serine/arginine-rich (SR) proteins are essential nuclear-localized splicing factors. We have investigated the dynamic subcellular distribution of the Arabidopsis (Arabidopsis thaliana) RSZp22 protein, a homolog of the human 9G8 SR factor. Little is known about the determinants underlying the control of plant SR protein dynamics, and so far most studies relied on ectopic transient overexpression. Here, we provide a detailed analysis of the RSZp22 expression profile and describe its nucleocytoplasmic shuttling properties in specific cell types. Comparison of transient ectopic- and stable tissue-specific expression highlights the advantages of both approaches for nuclear protein dynamic studies. By site-directed mutagenesis of RSZp22 RNA-binding sequences, we show that functional RNA recognition motif RNP1 and zinc-knuckle are dispensable for the exclusive protein nuclear localization and speckle-like distribution. Fluorescence resonance energy transfer imaging also revealed that these motifs are implicated in RSZp22 molecular interactions. Furthermore, the RNA-binding motif mutants are defective for their export through the CRM1/XPO1/Exportin-1 receptor pathway but retain nucleocytoplasmic mobility. Moreover, our data suggest that CRM1 is a putative export receptor for mRNPs in plants.
RESEARCH IN PHYSICS
Authors: Dodge Homer L.
Published: March 2010

It is the object of this department to present to teachers of physics the results of recent research. In so far as is possible, the articles and items will be non‐technical, and it is hoped that they will furnish material which will be of value in the classroom. Suggestions and contributions should be sent to Homer L. Dodge, Department of Physics, University of Oklahoma, Norman, Oklahoma.
LABORATORY PLANNING AND EQUIPMENT
Authors: Wright William Albert Earl
Published: March 2010

[It is hoped that this article will prove of interest, not only to those chemistry teachers who are so fortunate as to be about to have the privilege of helping to design their own new laboratories but also to many others who want to keep informed in regard to recent advances in the matter of materials and construction. In the case of teachers who are actively engaged in planning laboratories it is urged that they get in touch with their architects very early in the course of the planning so that they may not be handicapped by previous determination of structural members. For those who are not acquainted with it the splendid volume on Laboratory Construction and Equipment gotten out in 1930 by the National Research Council and published by The Chemical Foundation is highly recommended. F. B. Wade.]
Software Reviews
Authors: McGrath Diane
Published: March 2010

Planet Earth: Gaia Library

A Field Trip to the Rainforest
Software Reviews
Authors: McGrath Diane
Published: March 2010

Mental Math Games (Series 1)

Wonderland Puzzles
Book Reviews
Authors: Shroyer Gail
Published: March 2010

Book reviewed in this article:

Invisible Bugs and Other Creepy Creatures That Live With You, Susan Lang.

How We Learned The Earth Is Round, Patricia Lauber.

Dirt‐Cheap Science: Activity‐Based Units, Games, Experiments & Reproducibles, Esther Weiner.
The Berlin‐White Integrated Science and Mathematics Model
Authors: Berlin Donna F. , White Arthur L.
Published: March 2010

Science and mathematics are naturally and logically related in the real world. Educators are trying to capture this relationship in the classroom in an effort to improve students' achievement and attitude in both disciplines. However, the literature abounds with terms and definitions related to the integration of science and mathematics education. The Berlin‐White Integrated Science and Mathematics (BWISM) Model was developed to provide a template to characterize current resources, guide in the development of new materials, and provide a common language to advance the research base related to integrated science and mathematics teaching and learning.
INVITED COMMENTS
Authors: Koenig Darlene , Kuznik Frank
Published: March 2010

Editor's Note: The Lead Teacher Component of the Virginia State Systemic Initiative has developed a special relationship with USA TODAY; they are a national newspaper with special daily materials to help teachers use newspapers in several disciplines. These materials are provided to teachers at cost. SSMA and Virginia are not endorsing USA TODAY; we are simply trying to make it easier for teachers to use newspapers; whether they use USA TODAY or a local newspaper is of no concern. We just find that the support provided by USA TODAY definitely helps teachers get started. Thus, we asked the authors, writers in Educational Development for USA TODAY, to prepare this article so that our readers may learn of their service to teachers.
Integrating Science and Mathematics: Perceptions of Preservice and Practicing Elementary Teachers
Authors: Lehman Jeffrey R.
Published: March 2010

One hundred and sixty‐one undergraduate elementary education majors and sixty elementary teachers completed an eight‐item questionnaire designed to assess their perceptions toward integrating science and mathematics in the elementary grades. The two groups of subjects differed significantly on their responses to five of the eight items. Chi square analyses suggest that practicing elementary teachers felt they had more background in mathematics and science, were more aware of curriculum materials in this area, did not think that integration was currently a common practice, and were more likely to indicate that there was not sufficient time in the school day to integrate the subjects. Preservice teachers were more likely to indicate that integrating the disciplines was preferred to teaching them separately. In addition to the analyses of data, a list of recommendations are provided for teachers, curriculum developers, and policy makers interested in advancing the concept of integrating science and mathematics in instruction.
Student Reactions to Learning About Probability and Statistics: Evaluating the Quantitative Literacy Project
Authors: Garfield Joan , Ahlgren Andrew
Published: March 2010

The NCTM “Curriculum and Evaluation Standards for School Mathematics” (1989) reflect the current movement to introduce probability and statistics in the precollege curriculum. These standards include topics and principles for instruction in probability and statistics which are included in the Quantitative Literacy Project (QLP) curriculum materials. This paper presents results of a survey which explored the successes of the QLP materials in terms of student reactions to instruction in probability and statistics.

A student survey of 917 students of teachers trained in QLP workshops assessed how students regarded the instructional materials in general, how well they liked learning topics in probability and statistics, and how well they believed that they had learned the content. Results indicated that students have mostly positive attitudes towards learning statistics. However, fewer students felt it was useful to learn about these topics. An increase in positive attitudes with grade level suggests the topics may be received more favorably and, therefore, may more appropriately be used in higher grades.
African Science, African and African‐American Scientists and the School Science Curriculum
Authors: Murfin Brian
Published: March 2010

The need for multicultural science education for all students is discussed in this paper. The nature of science in Africa is compared to traditional Western science and the pros and cons of each are examined, Contributions to scientific knowledge by Africans and African‐Americans are then considered. Finally, suggestions are given on integrating the contributions of Africans and African‐Americans into the science classroom and curriculum.
Archimedes and Pi ‐ Revisited
Authors: Bidwell James K.
Published: March 2010

Archimedes of Syracuse (287‐212 B.C.) created the first known recursion process for estimating the value of π. The “classical method” of Archimedes is developed and programs for the TI‐81 calculator are given for finding the upper and lower bounds. This classical method is compared with the Gregory‐Machin infinite series method (after 1706). A Tl‐81 program is given for this method.
A Review of the Use and Implementation of Science Field Trips
Authors: Rudmann Cathryn L.
Published: March 2010

Field trips have become a popular component of many nonformal science education programs. Teachers, principals and parents typically value the field trip experience. They support the periodic use of this nonformal learning experience for its affective benefits with the assumption that cognitive gains are also achieved. But is this belief supported with accurate accounts of cognitive and affective improvements? This review begins with a brief historical view of field trips, summarizes various studies of the implementation of science field trips, and provides suggestions for integrating field trips into the science curriculum.
BOOK REVIEWS
Authors: Abdi S. Wali
Published: March 2010

Book reviewed in this article:

Cabell's Directory of Publishing Opportunities in Education, Third Edition, David W. E. Cabell

The Bones Book And Skeleton Gamebook, Stephen Cumbaa

Thinking Connections: Learning to Think and Thinking to Learn, D.N. Perkins, H. Goodrich, S. Tishman, J. M. Owen
“Chemistry On Stage”—A Strategy for Integrating Science and Dramatic Arts
Authors: Budzinsky Fie K.
Published: March 2010

In most classrooms throughout the United States, science curricula are still presented by utilizing approaches and materials that focus on science alone rather than integrating science content with other disciplines. The purpose of this article is to provide the reader with a strategy for merging two subject areas that are often perceived to be at opposite ends of the educational spectrum—science and dramatic arts. Students select and research the life of a scientist who furthered the discipline of chemistry. Utilizing this information, they create an on‐stage theatrical production—including script, set, costumes, and props. The mini‐production portrays some of the personal aspects of the scientist's life as well as replicating or simulating a significant contribution made to the chemistry field.
The Effects of Teachers and Schooling on the Vocational Choice of University Research Scientists
Authors: Rowsey Robert E.
Published: March 2010

Thirty‐five research scientists from the academic areas of Chemistry, Geology, Physics and Zoology were surveyed to obtain information regarding the effect of teachers and formal schooling on their decisions to become scientists. All subjects included in the study held the PhD. degree and were actively involved in research. Data analysis indicated that 63 percent of the subjects had identified a genuine interest in science by the time they were in the ninth grade, but only 9 percent of them attributed this interest to their elementary or junior high school teachers. The data revealed that 43 percent of the population were influenced to become scientists by one or more high school teachers. Also, one‐third of the subjects had made the decision to become a scientist by the time of high school graduation. Most of the other two‐thirds of the individuals studied decided to become scientists because of the influence of college professors in their freshman‐and sophomore‐level courses. The subjects were asked if particular events that occurred in junior or senior high school science classes positively influenced them to become scientists. Seventy‐eight percent of the subjects responded that there were no classroom activities occurring that attracted them to science.
Measurement of Length: The Need for a Better Approach to Teaching
Authors: Kamii Constance , Clark Faye B.
Published: March 2010

Three hundred and eighty‐three children in grades 1–5 were individually interviewed to find out at when they construct unit iteration out of transitive reasoning as described by Piaget, Inhelder, and Szeminska (1960). The results indicated that most children (72%) construct transitive reasoning by second grade and that most (76%) construct unit iteration out of transitive reasoning by fourth grade. The article explains why traditional instruction produces the poor results revealed by the National Assessment of Educational Progress. It also suggests a better approach to the teaching of measurement that presents problems and encourages children to modify their ways of thinking.
Practitioner's Research: A Study in Changing Preservice Teachers’ Conceptions About Mathematics and Mathematics Teaching and Learning
Authors: Steele Diana F. , Widman Teresa Fehrs
Published: March 2010

Educators involved in the current reform movement in mathematics education recommend that students be actively involved in constructing their own knowledge and developing powerful mathematical concepts. This study suggests how ideas based on constructivist learning theory can be put into practice in a preservice mathematics education class.
Science Teacher Beliefs and Intentions Regarding the Use of Cooperative Learning
Authors: Lumpe Andrew T. , Haney Jodi J. , Czerniak Charlene M.
Published: March 2010

The use of cooperative learning is a recurring theme in recommendations for science education, and numerous studies have documented its effectiveness in the classroom. However, teachers' beliefs about using cooperative learning may play an important role in its ultimate implementation. The primary purpose of this study was to examine the factors influencing K‐12 teachers' intentions to use cooperative learning in their science instruction. The Theory of Planned Behavior was used in this study to assess the potential influence of three belief‐based constructs: attitude, subjective norm, and perceived control. Salient beliefs about cooperative learning were first identified, scales were developed to measure the theory constructs, and a random sample of K‐12 teachers responded to the scales. Two constructs, attitude and perceived behavioral control, were found to be significant influences and accounted for 62% of the variance in the teachers' intent to use cooperative learning in their own science instruction. Specific suggestions for addressing beliefs about cooperative learning and professional development strategies are offered.
How History and Philosophy in the US Science Education Standards Could Have Promoted Multidisciplinary Teaching
Authors: Matthews Michael R.
Published: March 2010

Based on the forthcoming book, Time for Science Education (Matthews, in press), this article notes that the US National Science Education Standards advocate liberal, contextual, or cultural goals for science education, including the expectation that students will understand a certain amount of the historical and cultural significance of science. After mentioning something of the rich role played by the pendulum in the foundation of modern science, in solving the longitude problem, in establishing a universal length standard, and in allowing the creation of an accurate timekeeper, as well as the pendulum clock's function in philosophy and theology, the article draws attention to the scant treatment given the pendulum in the Standards. Opportunities are thus lost for realizing the Standards' laudable goals for US science education. Finally, it is claimed that realizing these cultural goals for science education requires more routine incorporation of the history and philosophy of science into preservice and inservice courses for science teachers.
A Vision Educators Can Put Into Practice: Portraying the Constructivist Classroom as a Cultural System
Authors: Windschitl Mark
Published: March 2010

Constructivist perspectives on learning have helped math and science educators better understand how students make sense of their experiences. Unfortunately, the intuitively appealing explanations of how learners construct knowledge have not been translated into a systematic body of pedagogical methods or a coherent curricular approach. Constructivist teaching is often portrayed in the literature as an alternative to traditional instructional approaches or as a toolbox of pedagogical techniques. These incomplete images do little to help practitioners understand constructivism or how it should be integrated into the life of the classroom. There may, however, be help for teachers in conceptualizing constructivism as a foundation for classroom practice. Recent anthropological investigations of learning have directed attention to the culture of classroom environments and the characteristic norms, beliefs, and practices that participants share in their dealings with one another. This article contends that envisioning the classroom as an articulated system of beliefs and practices not only serves an explanatory function for learning theorists but, more importantly, serves as a heuristic for teachers in conceptualizing constructivism and offers a starting point for teachers in implementing constructivist practices.
Informal Science Experience, Attitudes, Future Interest in Science, and Gender of High‐Ability Students: An Exploratory Study
Authors: Joyce Beverly A. , Farenga Stephen J.
Published: March 2010

The present study examined specific science‐related attitudes, informal science‐related experiences, future interest in science, and gender of young high‐ability students. The sample consisted of 111 high‐ability students between the ages of 9 and 13. Students completed the Test of Science Related Attitudes (TOSRA), the Science Experience Survey, and the Course Selection Sheet. Two regression models were developed to predict number of physical science and life science courses selected. In the first model, gender, TOSRA subscale Career Interest in Science, and informal physical science related experience predicted 42% of the variance related to number of physical science courses selected. The second model (R2= .24) predicted number of life science courses based on informal life science related experience, informal physical science related experience, and TOSRA subscale Enjoyment of Science Lessons. Recommendations were made recognizing differences regarding gender and ability level.
Special Issue Article: Preparing for the 21st Century: The Status of Quantitative Literacy in the United States
Authors: Wilkins Jesse L. M.
Published: March 2010

This article articulates and operationalizes a framework for investigating the level of quantitative literacy in the United States. Quantitative literacy is defined in terms of mathematical content knowledge, mathematical reasoning, understanding of the social impact and utility of mathematics, understanding the nature and historical development of mathematics, and mathematical disposition‐Data from the Third International Mathematics and Science Study are used to document the level of quantitative literacy in the US. Results suggest that, although students in the US seem to possess an awareness of the usefulness of mathematics and have positive dispositions toward mathematics, they fall short in their understanding of the nature of mathematics and an ability to apply their content knowledge to everyday situations. Suggestions for curriculum and instruction that align with the framework for promoting quantitative literacy are offered.
Examining the Effects of a Reformed Junior High School Science Class on Students' Math Achievement
Authors: Judson Eugene , Sawada Daiyo
Published: March 2010

Though national standards emphasize the importance of connections between math and science, few empirical studies exist to support the notion that student achievement increases from such integration. This paper examines an eighth‐grade science class that integrated mathematics into science through the use of technology. In a setting of action research, the effects of such integration were examined. This paper reports that integrating mathematics into the science class positively affected students' achievement in their math class and describes the circumstances under which the integration occurred.
The Effects of Fins on the Intermediate Wake of a Submarine Model
Authors: Jiménez Juan M. , Reynolds Ryan T. , Smits Alexander J.
Published: March 2010

Results are presented on the behavior of the turbulent wake behind a submarine model for a range of Reynolds numbers based on the model length between 0.49×106 and 1.8×106, for test locations between 3 and 9 diameters downstream of the stern. The shape of the model emulates an idealized submarine, and tests were performed with and without stern fins. In the absence of fins, the velocity profile in planes away from the influence of the sail rapidly becomes self-similar and is well described by a function of exponentials. The fins create defects in the velocity profiles in the outer region of the wake, while yielding higher values of turbulence at locations corresponding to the tips of the fins. Measurements conducted in planes away from the midline plane show that the velocity profiles remain self-similar, while the shear stress profiles clearly show the effects of the necklace vortices trailing from the base of the fins.
Adjustment of Aerodynamic-Compensation Characteristics of a Pitot Tube by Rear-Body Shape Manipulation
Authors: Masud Jehanzeb , Akram Farooq bin
Published: March 2010

In this paper we present a methodology for adjustment of subsonic compensation characteristics of an aerodynamic-compensation Pitot tube. This methodology is based on manipulation of a Pitot tube profile (shape) downstream of the static pressure port such that its subsonic characteristics are modified while the supersonic characteristics remain unchanged. Due to this “rear-body” shape adjustment, complete redesign of a developed or in service Pitot tube is not required. We have used computational fluid dynamics tools in the analysis and design refinement of a Pitot tube by rear-body shape adjustment. The complete Mach number regime (M<2) has been computationally analyzed for three different rear-body profiles. The results of our study indicate that significant variation in subsonic compensation characteristics of a Pitot tube is possible by this method.
What Is the Best Launch Angle To Hit a Home Run?
Authors: Kagan David
Published: March 2010

Your students will proudly raise their hands and answer, “45 degrees!” They are, however, answering a different question. It is true that in the absence of air resistance, for a given initial speed, the launch angle that maximizes the range is 45°. For a real homer, there are many complicating factors that make the question far more challenging to answer. Here is a partial list: 1. The initial speed off the bat is not fixed. Garvey's law, “The harder you hit it, the further it goes” is definitely at play; 2. Air resistance is a substantial influence on the flight of the ball.1; 3. The backspin on a well-hit ball creates lift due to the Magnus effect.2; 4. Atmospheric conditions such as humidity, temperature, air density, and the wind affect the motion as well.3; 5. Baseball parks are unique in size and shape. So, a home run in one park may not be a home run in another.
Need a Classroom Stimulus? Introduce Radio Astronomy
Authors: Derman Samuel
Published: March 2010

Silently, invisibly, ceaselessly, our planet Earth is showered by radio waves from every direction and from every region of space. This radio energy originates in our solar system, throughout the Milky Way galaxy, and far beyond, out to the remotest reaches of the universe. Detecting and unraveling the origins of these invisible signals is what radio astronomy is all about. This ever-present radiation provides astronomers with an alternate, non-optical window to the universe, revealing exotic and unfamiliar phenomena previously undetected by even the most powerful optical telescopes. For physics teachers, a classroom discussion of these radio discoveries, however brief, offers an opportunity for igniting interest (and possibly a career option) in even the most apathetic of students. This paper describes, first, the background of some of these events, and second (in the appendixes), a selection of numerical problems so that students can derive for themselves the truly mind-stretching features of these celestial objects.
Project YouTube
Authors: Riendeau Diane
Published: March 2010

Thanks to Jim Hicks, Harrington High School (retired), Harrington, IL, for the numerous emails regarding this idea!
Microcavity Laser Oscillating in a Circuit-Based Resonator
Authors: Walther Christoph , Scalari Giacomo , Amanti Maria Ines , Beck Mattias , Faist Jérôme
Published: March 2010

Small Is Beautiful

Shrinking the size of lasers is attractive because it generally leads to a reduction in power requirements, an increase in switching speed, and possibly a cleaner output.

Walther
et al.

(p.
1495
) combined patterned electronic components (inductor and capacitor) and an active gain material to develop a submillimeter laser that emits in the microwave regime at low temperature. The use of established patterning techniques and tunable superlattice structures offer the prospect of shrinking the size still further, as well as providing a route to designer laser output for high-speed information transport and optical processing.
Ferrous Polycrystalline Shape-Memory Alloy Showing Huge Superelasticity
Authors: Tanaka Y. , Himuro Y. , Kainuma R. , Sutou Y. , Omori T. , Ishida K.
Published: March 2010

Ferrous Shape Memory Alloy

So-called shape memory alloys “remember” the shape they are processed into, and can return to that shape after being deformed by heat. A limitation for most metal-based shape memory alloys is the extent to which they can be deformed elastically.

Tanaka
et al.

(p.
1488
; see the Perspective by

Ma and Karaman

) demonstrate an iron-based alloy that shows much higher levels of superelastic strain, surpassing the performance of nickel-titanium alloys. In addition to high superelastic strain, this ferrous shape memory alloy has much higher strength than NiTi and copper-based shape memory alloys and, consequently, a high-energy absorption capability. These properties may allow shape memory alloys to be exploited as strain sensors or energy dampers.
Variation in Transcription Factor Binding Among Humans
Authors: Kasowski Maya , Grubert Fabian , Heffelfinger Christopher , Hariharan Manoj , Asabere Akwasi , Waszak Sebastian M. , Habegger Lukas , Rozowsky Joel , Shi Minyi , Urban Alexander E. , Hong Mi-Young , Karczewski Konrad J. , Huber Wolfgang , Weissman Sherman M. , Gerstein Mark B. , Korbel Jan O. , Snyder Michael
Published: March 2010

Like Father, Like Mother, Like Child

Transcriptional regulation is mediated by chromatin structure, which may affect the binding of transcription factors, but the extent of how individual-to-individual genetic variation affects such regulation is not well understood.

Kasowski
et al.

(p.
232
, published online 18 March) investigated the binding of two transcription factors across the genomes of human individuals and one chimpanzee. Transcription factor binding was associated with genomic features such as nucleotide variation, insertions and deletions, and copy number variation. Thus, genomic sequence variation affects transcription factor binding and may explain expression difference among individuals.

McDaniell
et al.

(p.
235
, published online 18 March) provide a genome-wide catalog of variation in chromatin and transcription factor binding in two parent-child trios of European and African ancestry. Up to 10% of active chromatin binding sites were specific to a set of individuals and were often inherited. Furthermore, variation in active chromatin sites showed heritable allele-specific correlation with variation in gene expression.
Evaluation of a Novel Broad-Spectrum PCR-Multiplex Genotyping Assay for Identification of Cutaneous Wart-Associated Human Papillomavirus Types
Authors: de Koning Maurits N. C. , ter Schegget Jan , Eekhof Just A. H. , Kamp Marga , Kleter Bernhard , Gussekloo Jacobijn , Feltkamp Mariet C. W. , Bouwes Bavinck Jan Nico , Purdie Karin J. , Bunker Christopher B. , Proby Charlotte M. , Meys Rhonda , Harwood Catherine A. , Quint Wim G. V.
Published: March 2010

A large number of human papillomavirus (HPV) types, distributed over five papillomavirus genera, are detectable in the skin. HPV types belonging to the alpha, gamma, and mu genera have been detected in cutaneous warts. A state-of-the-art HPV genotyping assay for these cutaneous wart-associated HPV types does not exist although warts constitute a highly prevalent skin condition, especially in children (33%) and organ transplant recipients (45%). Cutaneous warts are again the focus of attention as their clinical relevance rises with the increasing number of chronically immunosuppressed patients. The objective of this study was to develop and evaluate a DNA-based genotyping system for all known cutaneous wart-related HPV types using PCR and Luminex xMAP technology. The broad-spectrum PCR amplified DNA of all known wart-associated HPV types from the genera alpha (HPVs 2, 3, 7, 10, 27, 28, 29, 40, 43, 57, 77, 91, and 94), gamma (HPVs 4, 65, 95, 48, 50, 60, and 88), mu (HPVs 1 and 63), and nu (HPV41). The probes were evaluated using plasmid HPV DNA and a panel of 45 previously characterized cutaneous wart biopsy specimens showing high specificity. HPV was also identified in 96% of 100 swabs from nongenital cutaneous warts. HPV types 1, 2, 27, and 57 were the most prevalent HPV types detected in 89% of the swabs. In conclusion, this Luminex-based genotyping system identifies all known cutaneous wart HPV types including phylogenetically related types, is highly HPV type specific, and is suitable for large-scale epidemiological studies.
NovelBurkholderiales23S rRNA Genes Identified in Ileal Biopsy Samples from Children: Preliminary Evidence that a Subtype Is Associated with Perianal Crohn's Disease
Authors: Sim W. H. , Wagner J. , Cameron D. J. , Catto-Smith A. G. , Bishop R. F. , Kirkwood C. D.
Published: March 2010

A novel family ofBurkholderialesbacteria was identified in ileal biopsy specimens from children presenting with symptoms of inflammatory bowel disease. A molecular subtyping approach based on sequencing of a variable region of the bacteria's 23S rRNA genes identified three variants. Pilot analysis identified one variant to be significantly associated with perianal Crohn's disease.
Unseasonal Transmission of H3N2 Influenza A Virus During the Swine-Origin H1N1 Pandemic
Authors: Ghedin Elodie , Wentworth David E. , Halpin Rebecca A. , Lin Xudong , Bera Jayati , DePasse Jay , Fitch Adam , Griesemer Sara , Hine Erin , Katzel Daniel A. , Overton Larry , Proudfoot Kathleen , Sitz Jeffrey , Szczypinski Bridget , StGeorge Kirsten , Spiro David J. , Holmes Edward C.
Published: March 2010

The initial wave of swine-origin influenza A virus (pandemic H1N1/09) in the United States during the spring and summer of 2009 also resulted in an increased vigilance and sampling of seasonal influenza viruses (H1N1 and H3N2), even though they are normally characterized by very low incidence outside of the winter months. To explore the nature of virus evolution during this influenza “off-season,” we conducted a phylogenetic analysis of H1N1 and H3N2 sequences sampled during April to June 2009 in New York State. Our analysis revealed that multiple lineages of both viruses were introduced and cocirculated during this time, as is typical of influenza virus during the winter. Strikingly, however, we also found strong evidence for the presence of a large transmission chain of H3N2 viruses centered on the south-east of New York State and which continued until at least 1 June 2009. These results suggest that the unseasonal transmission of influenza A viruses may be more widespread than is usually supposed.
Macropinocytotic Uptake and Infection of Human Epithelial Cells with Species B2 Adenovirus Type 35
Authors: Kälin Stefan , Amstutz Beat , Gastaldelli Michele , Wolfrum Nina , Boucke Karin , Havenga Menzo , DiGennaro Fabienne , Liska Nicole , Hemmi Silvio , Greber Urs F.
Published: March 2010

Human adenovirus serotype 35 (HAdV-35; here referred to as Ad35) causes kidney and urinary tract infections and infects respiratory organs of immunocompromised individuals. Unlike other adenoviruses, Ad35 has a low seroprevalence, which makes Ad35-based vectors promising candidates for gene therapy. Ad35 utilizes CD46 and integrins as receptors for infection of epithelial and hematopoietic cells. Here we show that infectious entry of Ad35 into HeLa cells, human kidney HK-2 cells, and normal human lung fibroblasts strongly depended on CD46 and integrins but not heparan sulfate and variably required the large GTPase dynamin. Ad35 infections were independent of expression of the carboxy-terminal domain of AP180, which effectively blocks clathrin-mediated uptake. Ad35 infections were inhibited by small chemicals against serine/threonine kinase Pak1 (p21-activated kinase), protein kinase C (PKC), sodium-proton exchangers, actin, and acidic organelles. Remarkably, the F-actin inhibitor jasplakinolide, the Pak1 inhibitor IPA-3, or the sodium-proton exchange inhibitor 5-(
N
-ethyl-
N
-isopropyl) amiloride (EIPA) blocked endocytic uptake of Ad35. Dominant-negative proteins or small interfering RNAs against factors driving macropinocytosis, including the small GTPase Rac1, Pak1, or the Pak1 effector C-terminal binding protein 1 (CtBP1), potently inhibited Ad35 infection. Confocal laser scanning microscopy, electron microscopy, and live cell imaging showed that Ad35 colocalized with fluid-phase markers in large endocytic structures that were positive for CD46, αν integrins, and also CtBP1. Our results extend earlier observations with HAdV-3 (Ad3) and establish macropinocytosis as an infectious pathway for species B human adenoviruses in epithelial and hematopoietic cells.
NETWORKS OF SPRINGS: A PRACTICAL APPROACH
Authors: ZANIN MASSIMILIANO , BULDÚ JAVIER M. , BOCCALETTI STEFANO
Published: March 2010

In the current work, we study the propagation of perturbations through networks of springs which are spatially distributed on a plane. We show that the topological properties of the network are related to the dissipation of energy within the system. By varying the rewiring parameter of the graph, and thus going from a regular to a random structure, we obtain a lower energy output, due to the fact that the initial (linear) perturbation is transformed into oscillations around each node. The results obtained are related to the transmission of information through a complex structure with potential applications to the design of more efficient damping systems.
LOWER SEMICONTINUITY RESULTS FOR FREE DISCONTINUITY ENERGIES
Authors: AMAR M. , DE CICCO V. , FUSCO N.
Published: March 2010

We establish new lower semicontinuity results for energy functionals containing a very general volume term of polyconvex type and a surface term depending on the spatial variable in a discontinuous way.
PROGRESS IN THE APPLICATION OF LOWER BOUND DIRECT METHODS IN STRUCTURAL DESIGN
Authors: WEICHERT DIETER , HACHEMI ABDELKADER
Published: March 2010

Based on the lower-bound direct methods, namely limit and shakedown analysis, it is shown in this paper how these methods can be used in a constructive manner for structural industrial design. The proposed methods are based on finite element analyses and numerical optimization to determine the admissible loading. Numerical applications are presented and compared with existing results in literatures.
m-ISOMETRIC OPERATORS ON BANACH SPACES
Authors: Sid Ahmed Ould Ahmed Mahmoud
Published: March 2010

We introduce the class of m-isometric operators on Banach spaces. This generalizes to Banach space the m-isometric operators on Hilbert space introduced by Agler and Stankus. We establish some basic properties and we introduce the notion of m-invertibility as a natural generalization of the invertibility on Banach spaces.
DISTRIBUTIVE PSEUDOCOMPLEMENTED SEMILATTICES
Authors: Celani Sergio A.
Published: March 2010

In this paper we will extend the topological duality given in [1] to the class of distributive pseudocomplemented semilattices and to the class of distributive Stone semilattices.
LU-FACTORIZATIONS OF SYMMETRIC MATRICES WITH APPLICATIONS
Authors: Qian Guoyou , Lu Jingya
Published: March 2010

In this paper, we describe explicitly the LU -factorization of a symmetric matrix of order n with n ≤ 7 when each of its ordered principal minors is nonzero. By using this result and some other related results on non-singularity previously given by Smith, Beslin, Hong, Lee and Ligh in the literature, we establish several theorems concerning LU -factorizations of power GCD matrices, power LCM matrices and reciprocal power GCD matrices and reciprocal power LCM matrices.
An eye localization, tracking and blink pattern recognition system
Authors: Wu Junwen , Trivedi Mohan M.
Published: March 2010

This study is to investigate the fundamental problems of, (1) facial feature detection and localization, especially eye features; and (2) eye dynamics, including tracking and blink detection. We first describe our contribution to eye localization. Following that, we discuss a simultaneous eye tracking and blink detection system. Facial feature detection is solved in a general object detection framework and its performance for eye localization is presented. A binary tree representation based on feature dependency partitions the object feature space in a coarse to fine manner. In each compact feature subspace, independent component analysis (ICA) is used to get the independent sources, whose probability density functions (PDFs) are modeled by Gaussian mixtures. When applying this representation for the task of eye detection, a subwindow is used to scan the entire image and each obtained image patch is examined using Bayesian criteria to determine the presence of an eye subject. After the eyes are automatically located with binary tree-based probability learning, interactive particle filters are used for simultaneously tracking the eyes and detecting the blinks. The particle filters use classification-based observation models, in which the posterior probabilities are evaluated by logistic regressions in tensor subspaces. Extensive experiments are used to evaluate the performance from two aspects, (1) blink detection rate and the accuracy of blink duration in terms of the frame numbers; (2) eye tracking accuracy. We also present an experimental setup for obtaining the benchmark data in tracking accuracy evaluation. The experimental evaluation demonstrates the capability of this approach.