bluuebunny/crossref_metadata_2025 huggingface dataset:
Relational Databases: A Transparent Framework for Encouraging Biology Students To Think Informatically
Authors: Rice Michael , Gladstone William , Weir Michael
Published: March 2006

We discuss how relational databases constitute an ideal framework for representing and analyzing large-scale genomic data sets in biology. As a case study, we describe a Drosophila splice-site database that we recently developed at Wesleyan University for use in research and teaching. The database stores data about splice sites computed by a custom algorithm using Drosophila cDNA transcripts and genomic DNA and supports a set of procedures for analyzing splice-site sequence space. A generic Web interface permits the execution of the procedures with a variety of parameter settings and also supports custom structured query language queries. Moreover, new analytical procedures can be added by updating special metatables in the database without altering the Web interface. The database provides a powerful setting for students to develop informatic thinking skills.
Use of Animation in Teaching Cell Biology
Authors: Stith Bradley J.
Published: March 2006

To address the different learning styles of students, and because students can access animation from off-campus computers, the use of digital animation in teaching cell biology has become increasingly popular. Sample processes from cell biology that are more clearly presented in animation than in static illustrations are identified. The value of animation is evaluated on whether the process being taught involves motion, cellular location, or sequential order of numerous events. Computer programs for developing animation and animations associated with cell biology textbooks are reviewed, and links to specific examples of animation are given. Finally, future teaching tools for all fields of biology will increasingly benefit from an expansion of animation to the use of simulation. One purpose of this review is to encourage the widespread use of animations in biology teaching by discussing the nature of digital animation.
The University of Alabama at Birmingham Center for Community OutReach Development Summer Science Institute Program: A 3-Yr Laboratory Research Experience for Inner-City Secondary-Level Students
Authors: Niemann Marilyn A. , Miller Michael L. , Davis Thelma
Published: March 2006

This article describes and assesses the effectiveness of a 3-yr, laboratory-based summer science program to improve the academic performance of inner-city high school students. The program was designed to gradually introduce such students to increasingly more rigorous laboratory experiences in an attempt to interest them in and model what “real” science is like. The students are also exposed to scientific seminars and university tours as well as English and mathematics workshops designed to help them analyze their laboratory data and prepare for their closing ceremony presentations. Qualitative and quantitative analysis of student performance in these programs indicates that participants not only learn the vocabulary, facts, and concepts of science, but also develop a better appreciation of what it is like to be a “real” scientist. In addition, the college-bound 3-yr graduates of this program appear to be better prepared to successfully academically compete with graduates of other high schools; they also report learning useful job-related life skills. Finally, the critical conceptual components of this program are discussed so that science educators interested in using this model can modify it to fit the individual resources and strengths of their particular setting.
Book Review
Authors: Kalumuck Karen E. , Doss Kristina
Published: March 2006

The National Institutes of Health publishes a series of science curriculum supplements for K-12 education that are available from their Web site free of charge ( http://science.education.nih.gov/supplements ). In this feature, we review two of the high school supplements, Human Genetic Variation and Cell Biology and Cancer. Overall, we find that they are both excellent resources that engage students in learning science content while emphasizing the impact of scientific breakthroughs on personal and public health. In this review, we highlight the many strong features of the curricula and point out instances in which teachers may wish to seek out supplemental, updated information.
Probabilities and Predictions: Modeling the Development of Scientific Problem-Solving Skills
Authors: Stevens Ron , Johnson David F. , Soller Amy
Published: March 2006

The IMMEX (Interactive Multi-Media Exercises) Web-based problem set platform enables the online delivery of complex, multimedia simulations, the rapid collection of student performance data, and has already been used in several genetic simulations. The next step is the use of these data to understand and improve student learning in a formative manner. This article describes the development of probabilistic models of undergraduate student problem solving in molecular genetics that detailed the spectrum of strategies students used when problem solving, and how the strategic approaches evolved with experience. The actions of 776 university sophomore biology majors from three molecular biology lecture courses were recorded and analyzed. Each of six simulations were first grouped by artificial neural network clustering to provide individual performance measures, and then sequences of these performances were probabilistically modeled by hidden Markov modeling to provide measures of progress. The models showed that students with different initial problem-solving abilities choose different strategies. Initial and final strategies varied across different sections of the same course and were not strongly correlated with other achievement measures. In contrast to previous studies, we observed no significant gender differences. We suggest that instructor interventions based on early student performances with these simulations may assist students to recognize effective and efficient problem-solving strategies and enhance learning.
Teaching Systems Biology: An Active-learning Approach
Authors: Kumar Anuj
Published: March 2006

With genomics well established in modern molecular biology, recent studies have sought to further the discipline by integrating complementary methodologies into a holistic depiction of the molecular mechanisms underpinning cell function. This genomic subdiscipline, loosely termed“ systems biology,” presents the biology educator with both opportunities and obstacles: The benefit of exposing students to this cutting-edge scientific methodology is manifest, yet how does one convey the breadth and advantage of systems biology while still engaging the student? Here, I describe an active-learning approach to the presentation of systems biology. In graduate classes at the University of Michigan, Ann Arbor, I divided students into small groups and asked each group to interpret a sample data set (e.g., microarray data, two-hybrid data, homology-search results) describing a hypothetical signaling pathway. Mimicking realistic experimental results, each data set revealed a portion of this pathway; however, students were only able to reconstruct the full pathway by integrating all data sets, thereby exemplifying the utility in a systems biology approach. Student response to this cooperative exercise was extremely positive. In total, this approach provides an effective introduction to systems biology appropriate for students at both the undergraduate and graduate levels.
Genome Science: A Video Tour of the Washington University Genome Sequencing Center for High School and Undergraduate Students
Authors: Flowers Susan K. , Easter Carla , Holmes Andrea , Cohen Brian , Bednarski April E. , Mardis Elaine R. , Wilson Richard K. , Elgin Sarah C.R.
Published: March 2006

Sequencing of the human genome has ushered in a new era of biology. The technologies developed to facilitate the sequencing of the human genome are now being applied to the sequencing of other genomes. In 2004, a partnership was formed between Washington University School of Medicine Genome Sequencing Center's Outreach Program and Washington University Department of Biology Science Outreach to create a video tour depicting the processes involved in large-scale sequencing. “Sequencing a Genome: Inside the Washington University Genome Sequencing Center” is a tour of the laboratory that follows the steps in the sequencing pipeline, interspersed with animated explanations of the scientific procedures used at the facility. Accompanying interviews with the staff illustrate different entry levels for a career in genome science. This video project serves as an example of how research and academic institutions can provide teachers and students with access and exposure to innovative technologies at the forefront of biomedical research. Initial feedback on the video from undergraduate students, high school teachers, and high school students provides suggestions for use of this video in a classroom setting to supplement present curricula.
Holocene fire in the Scottish Highlands: evidence from macroscopic charcoal records
Authors: Froyd C. A.
Published: March 2006

It has been hypothesized that the mid-Holocene decline of pine (Pinus sylvestris L.) woodland in the Scottish Highlands may have been the result of a change in the fire regime of the region. Little is known about the Holocene fire history of these forests, although a number of factors suggest that fire may have played a significant role. This study examines whether fire was a prevalent factor in Scotland over the course of the Holocene and its relationship with Highland vegetation communities. Both macroscopic and microscopic charcoal are analysed in conjunction with a full palynological investigation from four Holocene lake sedimentary sequences in locations throughout the Scottish Highlands. Comparison of macroscopic charcoal abundance profiles with those from areas of known wildfire activity and the consistent pattern of burning revealed across the four disparate Highland sites indicate that broad-scale burning of vegetation did occur. Charcoal abundance was related to vegetation composition at all four of the sites examined. The abundance of pine, however, was found to be unrelated to fire history. Instead, fire appears to be predominantly linked to the development of heath and blanket mire communities. Analysis of three different macroscopic charcoal size fractions (? 500 gm, 250-500 gm and 125-250 gm) revealed strong correlations between measures. Microscopic charcoal abundance, however, was more variable and was determined to be a less accurate measure of local catchment-scale burning within the region.
Reconstruction of Holocene monsoon history from the Pearl River Estuary, southern China, using diatoms and carbon isotope ratios
Authors: Zong Y , Lloyd J. M. , Leng M. J. , Yim W. W.-S. , Huang G.
Published: March 2006

This study employs a multiproxy approach in the reconstruction of Holocene monsoon history from sedimentary sequences obtained from the Pearl River Estuary, southern China. A set of modern surface sediment samples were collected within and outside the estuary, and a sediment core was obtained from the mouth of the estuary. A range of modern environmental variables were recorded including water salinity (summer, winter and annual average) and water depth. The diatom results show a good relationship with water salinity, with marine diatoms dominating the more distal samples from outside the main estuary and freshwater diatoms dominating the proximal samples influenced by higher freshwater flux. This pattern is matched by the bulk organic carbon isotopes. The isotope values vary between -21.1 +0.3%0 for samples from the fully marine environment, between -23.2±0.8%. and -23.7±0.8%. for samples from the mid to outer estuary brackish water environment and less than -24.7 + 1.3%. for samples from the inner estuary close to the freshwater sources. Similarly, the C/N ratios vary from below 7+0.6 in the marine end-members to over 14.8 + 3.0 in the freshwater end-members. Both the diatom and carbon data from the sediment core reveal a significant increase in freshwater flux from 8500 cal. yr BP resulting from the enhanced summer monsoon regime in early Holocene. The strength of freshwater flux reached its highest between 7500 and 6000 cal. yr BP. In the last 6000 years, freshwater flux decreased towards present, reflecting a gradual weakening of the summer monsoon.
North American droughts of the mid to late nineteenth century: a history, simulation and implication for Mediaeval drought
Authors: Herweijer Celine , Seager Richard , Cook Edward R.
Published: March 2006

Unlike the major droughts of the twentieth century that are readily identified in the instrumental record, similar events in the nineteenth century have to be identified using a combination of proxy data, historical accounts and a sparse collection of early instrumental records. In the USA, three distinct periods of widespread and persistent drought stand out in these records for the latter half of the nineteenth century: 1856-1865, 1870-1877 and 1890-1896. Each of these events is shown to coincide with the existence of an anomalously cool, La Nifia-like tropical Pacific. To examine the physical mechanisms behind these droughts two ensembles of simulations with an atmosphere general circulation model (AGCM) were generated: the first forces an AGCM with the observed history of Sea Surface Temperatures (SSTs) everywhere from 1856 to 2001 (the GOGA experiment), the second forces the AGCM only with tropical Pacific SSTs, being coupled to a two-layer entraining mixed layer (ML) ocean elsewhere (the POGA-ML experiment). Owing to a sparsity of instrumental precipitation data at this time, proxy evidence from tree rings is used as verification. A comparison of modelled soil moisture with tree-ring reconstructions of the Palmer Drought Severity Index (PDSI), a proxy for soil moisture, from the North American Drought Atlas is made. Both the POGA-ML and GOGA ensemble means capture the three multi-year droughts of the mid to late nineteenth century, indicating that the droughts were SST forced. The similarity of the POGA-ML and GOGA simulations implies that the component of each drought signal that is forced by the SST is driven ultimately by the La Nifia-like tropical Pacific. The global atmosphere-ocean context of each of the mid to late-nineteenth century droughts reveals a zonally and hemispherically symmetric pattern consistent with forcing from the tropics. In addition, Rossby wave propagation from the cooler equatorial Pacific amplifies dry conditions over the USA. Finally, using published coral data for the last millennium to reconstruct a NINO 3.4 history, the modern-day relationship between NINO 3.4 and North American drought is applied to recreate two of the severest Mediaeval ‘drought epochs’ in the western USA. The large-scale spatial similarity to the Drought Atlas data demonstrates the potential link between a colder eastern equatorial Pacific and the persistent North American droughts of the Mediaeval period.
Extension of the New Zealand kauri (Agathis australis) chronology to 1724 BC
Authors: Boswijk Gretel , Fowler Anthony , Lorrey Andrew , Palmer Jonathan , Ogden John
Published: March 2006

Long tree-ring chronologies have been constructed in the Northern Hemisphere for dendroclimatology and palaeoenvironmental studies, radiocarbon calibration and archaeological dating. Numerous tree-ring chronologies have also been built in the Southern Hemisphere, primarily for dendroclimatology, but multimillennial chronologies are rare. Development of long chronologies from the Southern Hemisphere is therefore important to provide a long-term perspective on environmental change at local, regional and global scales. This paper describes the extension of the New Zealand Agathis australis (kauri) chronology from AD 911 to 1724 BC. Subfossil (swamp) kauri was collected from 17 swamp sites in the upper North Island. Kauri timbers were also obtained from an early twentieth century house on the University of Auckland campus. Twelve site chronologies and 11 independent tree-sequences were constructed and crossmatched to produce a 3631-yr record, which was calendar dated to 1724 BC-AD 1907 against the modern kauri master chronology. A new long chronology, AGAUc04a, was built by combining the modern kauri data with house timbers and subfossil kauri. This new chronology spans 1724 BC-AD 1998. It is of similar length to chronologies from Tasmania and South America and is the longest tree-ring chronology yet built in New Zealand. The greatest significance of the long kauri chronology lies in its potential as a high-quality palaeoclimate proxy, especially with regard to investigation of the El Ninio-Southern Oscillation phenomenon. The chronology also has application to investigation of extreme environmental events, dendroecology, archaeology and radiocarbon calibration.
A 1000-yr record of forest fire activity from Eclipse Icefield, Yukon, Canada
Authors: Yalcin Kaplan , Wake Cameron P. , Kreutz Karl J. , Whitlow Sallie I.
Published: March 2006

A 1000-yr record of forest fire activity has been developed using three annually dated ice cores from Eclipse Icefield, Yukon, Canada. Forest fire signals were identified as NH4plus residuals above a robust spline and corroborated by an empirical orthhogonal function (EOF) analysis that identified a chemical association in the NH4plus, C2042macr and Kplus records similar to that observed in forest fire plumes. These statistical techniques yielded similar records of forest fire activity, although the EOF analysis provides more conservative identification of forest fire signals. Comparison of forest fire signals in the Eclipse ice cores with the record of annual area burned in Alaska and the Yukon demonstrates that 80% of high fire years in Alaska and 79% of high fire years in the Yukon are identifiable as NH4plus concentration residuals in at least one core from Eclipse Icefield, although any individual core records 36-67% of these events. The Eclipse ice cores record high fire activity in the AD 1760s, 1780s, 1840s, 1860s, 1880s, 1890s, 1920s-1940s and 1980s. Peak fire activity occurred in the 1890s, possibly reflecting anthropogenic ignition sources associated with the large influx of people to the Yukon during the Klondike Gold Rush. Periods of low fire activity are evident during the 1770s, 181Os-1830s, 1850s, 1950s and 1960s. Extending our proxy of fire activity to AD 1000 using annual NH4plus concentrations from our one core that extends back this far provides evidence of high fire activity from 1240 to 1410 during the waning stages of the ‘Mediaeval Warm Period’.
Long-distance transport of macroscopic charcoal by an intensive crown fire in the Swiss Alps - implications for fire history reconstruction
Authors: Tinner Willy , Hofstetter Simone , Zeugin Fabienne , Conedera Marco , Wohlgemuth Thomas , Zimmermann Lukas , Zweifel Roman
Published: March 2006

The correct interpretation of charcoal records in a palaeoecological context requires the understanding of the sources and transport of charcoal particles. Conventionally, it is assumed that macroscopic charcoal particles are not transported far from fires ( c. 200m). Therefore macroscopic charcoal records are used to reconstruct local fire frequencies. However, the general scarcity of empirical and experimental evidence impedes a thorough check of this assumption. In this study we present the first unambiguous evidence of kilometre-scaled macroscopic charcoal transport in Europe. During the hot summer of 2003 an intensive crown fire occurred in Leuk, central Swiss Alps. It affected 300 ha of forest as well as 10 ha of pasture and fallow land. Litter traps and nets had been located approximately 5 km west and east of the burned area. The downwind site in the east (Jeizinen) recorded a strong charcoal fallout at 5.3 km from the fire edge. The observed charcoal influx of fragments with a size up to 1.3 cm reached average values of 0.144 and 0.098 mm2/Cm2 per fire (or yr) in five traps and two nets, respectively. These values are comparable with charcoal accumulations measured at only c. 50 m from large fires, suggesting that macroscopic charcoal transport does not decay rapidly to zero with increasing distance from the fire. We suggest a long-distance dispersal model for transport of macroscopic charcoal during large fire events. Reconstructions of local fire regimes may be affected by long-distance transport of macroscopic charcoal, although this problem is mitigated by the tendency of most macroscopic charcoal particles to be deposited within very short distances (< 50 m) from the fire edge.
Clinical management of Parkinson's disease dementia: pitfalls and progress
Authors: Samuel Michael , Maidment Ian , Boustani Malaz , Fox Chris
Published: March 2006

The non-motor symptoms of Parkinson's disease, which include cognitive, behavioural and psychological problems, are significant not just in epidemiological terms but also in their impact on patients and carers. Each symptom requires careful evaluation, owing to the potential overlap with comorbid conditions and also to the multiple aetiological pathways in Parkinson's disease. Such monitoring allows enhanced management. However, the diagnostic difficulties arising from these non-motor symptoms require further research. Here we describe the efficacy and some of the problems of medication used for non-motor symptoms, including antiparkinsonian medication, antipsychotics and acetylcholinesterase inhibitors.
Mental health of children with learning disabilities†
Authors: Allington-Smith Pru
Published: March 2006

Children and adolescents with learning disabilities have high rates of mental health problems and behavioural difficulties. Comorbid disorders such as epilepsy, autism and attention-deficit hyperactivity disorder are common. Despite this, many areas in the UK are failing to provide a psychiatric service for these young people and their families. The children suffer as a result and may have to move away from home unnecessarily, at enormous emotional and financial cost. Each area should have a specialised multidisciplinary health team working closely with colleagues from education and social services to assist these complex children and give them the best chance to fulfil their potential.
Informing progress towards race equality in mental healthcare: is routine data collection adequate?
Authors: Aspinall Peter J.
Published: March 2006

The quality, completeness and coverage of ethnicity data in mental health services has long been regarded as unsatisfactory. The Department of Health's new 5-year action plan for delivering race equality in mental healthcare seeks to improve this key building block by setting out actions to improve both the quality of information and its analysis and dissemination. However, those that are tangible and specific are few: annual surveys of service users, national censuses of mental health in-patients and tables of National Confidential Inquiry suicide cases and in-patient deaths by ethnicity. The opportunity to seek improvements in the quality and coverage of key routine data-sets such as ethnic monitoring in primary care and the Hospital Episode Statistics database has not been seized. Moreover, the plan does not mention proposed changes in civil registration (births and deaths) and the coroner service and their potential benefit. The continuing gaps in the information base justify a stronger emphasis on the processes necessary to bring about change rather than on what ethnic monitoring should provide.
Conversion disorder: the modern hysteria
Authors: Owens Colm , Dein Simon
Published: March 2006

Conversion disorders tend to be poorly understood and diagnosis can be difficult. In this article, we aim to clarify what conversion disorders are and how they can be distinguished from other psychiatric disorders that involve physical symptoms. Prevalence, prognosis and relationship to organic disease are controversial areas; we outline what is known about them and provide some historical context. Aetiological theories and management strategies are discussed, the latter with the aid of case vignettes.
Teaching psychodynamic formulation to psychiatric trainees Part 2: Teaching methods
Authors: Mace Chris , Binyon Sharon
Published: March 2006

Teaching methods to help students appreciate the value of psychodynamic formulation and to become more skilled in producing formulations are described. These are closely related to the four levels of our model formulation, each level corresponding to a set of competencies through which students should normally progress. Accurate diagnosis of a student's current capabilities and needs is crucial to effective teaching. Teaching methods at each level are illustrated through detailed reference to a case example. The usefulness of small-group discussion for assimilating clinical material within a clear framework is emphasised throughout.
Lagrange L4/L5 Points and the Origin of Our Moon and Saturn's Moons and Rings
Authors: GOTT J RICHARD
Published: March 2006

Abstract: The current standard theory of the origin of the Moon is that the Earth was hit by a giant impactor the size of Mars causing ejection of debris from its mantle that coalesced to form the moon; but where did this Mars‐sized impactor come from? Isotopic evidence suggests that it came from 1 AU radius in the solar nebula, and computer simulations are consistent with its approaching Earth on a zero‐energy parabolic trajectory. How could such a large object form at 1 AU in a quiescent disk of planetesimals without having already collided with the Earth at an earlier epoch before having the chance to grow large? Belbruno and Gott propose that the giant impactor could have formed in a stable orbit from debris at the Earth's Lagrange point L5 (or L4). It would grow quietly by accretion at L5 (or L4), but eventually gravitational perturbations by other growing planetesimals would kick it out into a horseshoe orbit and finally into a chaotic creeping orbit, which Belbruno and Gott show would, with high probability, hit the Earth on a near zero‐energy parabolic trajectory. We can see other examples of this phenomenon occurring in the solar system. Asteroid 2002AA29 is in a horseshoe orbit relative to the Earth that looks exactly like the horseshoe orbits that Belbruno and Gott found for objects that had been perturbed from L4/L5. The regular moons of Saturn are made of ice and have the same albedo as the ring particles (ice chunks, plus some dust). We (J. R. Gott, R. Vanderbei, and E. Belbruno) propose that the regular icy moons of Saturn (out to the orbit of Titan), which are all in nearly circular orbits, formed out of a thin disk of planetesimals (ice chunks) rather like the rings of Saturn today only larger in extent. In such a situation formation of objects at L4/L5 might be expected. Indeed, Saturn's moon Dione is accompanied by moons (Helene and Polydeuces) at both L4 and L5 Lagrange points, and Saturn's moon Tethys is also accompanied by moons (Telesto and Calypso) at both L4 and L5 Lagrange points. Epimetheus is in a horseshoe orbit relative to Janus that is exactly like the horseshoe orbit expected for an object that has been perturbed from a location at L4/L5. We propose that the rings of Saturn visible today are all that remains of this original disk; they lie inside the Roche limit where tidal forces have simply prevented the formation of large moons by accretion. Further out, the icy particles have accumulated into icy moons. Objects in external solar systems on horseshoe orbits (like those of Epimetheus relative to Janus) could be detected by a slow sinusoidal variation with time of the calculated mass of a planet from radial velocity measurements.
Phobos/Deimos Sample Return via Solar Sail
Authors: MATLOFF GREGORY L. , TAYLOR TRAVIS , POWELL CONLEY , MOTON TRYSHANDA
Published: March 2006

Abstract:A sample‐return mission to the Martian satellites using a con‐temporary solar sail for all post‐Earth‐escape propulsion is proposed. The 0.015 kg/m2areal mass‐thickness sail unfurls after launch and injection onto a Mars‐bound Hohmann‐transfer ellipse. Structure and payload increase spacecraft areal mass thickness to 0.028 kg/m2. During the Mars encounter, the sail functions as a parachute in the outer atmosphere of Mars to accomplish aerocapture. On‐board thrusters or the sail maneuver the spacecraft into an orbit with periapsis near Mars and apoapsis near Phobos. The orbit is circularized for Phobos‐rendezvous; surface samples are collected. The sail then raises the orbit for Deimos‐rendezvous and sample collection. The sail next places the spacecraft on an Earth‐bound Hohmann‐transfer ellipse. During Earth encounter, the sail accomplishes Earth‐aerocapture or partially decelerates the sample container for entry into the Earth's atmosphere. Mission mass budget is about 218 grams and mission duration is less than five years.
Canonical Formalism for Modelling and Control of Rigid Body Dynamics
Authors: GURFIL P
Published: March 2006

Abstract: This paper develops a new paradigm for stabilization of rigid‐body dynamics. The state‐space model is formulated using canonical elements, known as the Serret‐Andoyer (SA) variables, thus far scarcely used for engineering applications. The main feature of the SA formalism is the reduction of the dynamics via the underlying symmetry stemming from conservation of angular momentum and rotational kinetic energy. The controllability of the system model is examined using the notion of accessibility, and is shown to be accessible from all points. Based on the accessibility proof, two nonlinear asymptotic feedback stabilizers are developed: a damping feedback is designed based on the Jurdjevic‐Quinn method, and a Hamiltonian controller is derived by using the Hamiltonian as a natural Lyapunov function for the closed‐loop dynamics. It is shown that the Hamiltonian control is both passive and inverse optimal with respect to a meaningful performance index. The performance of the new controllers is examined and compared using simulations of realistic scenarios from the satellite attitude dynamics field.
Reduction of Lunar Landing Fuel Requirements by Utilizing Lunar Ballistic Capture
Authors: JOHNSON MICHAEL D. , BELBRUNO EDWARD A.
Published: March 2006

Abstract: Ballistic lunar capture trajectories have been successfully utilized for lunar orbital missions since 1991. Recent interest in lunar landing trajectories has occurred due to a directive from President Bush to return humans to the Moon by 2015. NASA requirements for humans to return to the lunar surface include separation of crew and cargo missions, all lunar surface access, and anytime‐abort to return to Earth. Such requirements are very demanding from a propellant standpoint. The subject of this paper is the application of lunar ballistic capture for the reduction of lunar landing propellant requirements. Preliminary studies of the application of weak stability boundary (WSB) trajectories and ballistic capture have shown that considerable savings in low Earth orbit (LEO) mission mass may be realized, on the order of 36% less than conventional Hohmann transfer orbit missions. Other advantages, such as reduction in launch window constraints and reduction of lunar orbit maintenance propellant requirements, have also surfaced from this study.
Assessing Potential Propulsion Breakthroughs
Authors: MILLIS MARC G.
Published: March 2006

Abstract: The term, propulsion breakthrough, refers to concepts like propellantless space drives and faster‐than‐light travel, the kind of breakthroughs that would make interstellar exploration practical. Although no such breakthroughs appear imminent, a variety of investigations have begun. During 1996–2002 NASA supported the breakthrough propulsion physics project to examine physics in the context of breakthrough spaceflight. Three facets of these assessments are now reported: (1) predicting benefits, (2) selecting research, and (3) recent technical progress. Predicting benefits is challenging, since the breakthroughs are still only notional concepts, but energy can serve as a basis for comparison. A hypothetical space drive would require many orders of magnitude less energy than a rocket for journeys to our nearest neighboring star. Assessing research options is challenging when the goals are beyond known physics and when the implications of success are profound. To mitigate the challenges, a selection process is described where: (1) research tasks are constrained to only address the immediate unknowns, curious effects, or critical issues; (2) reliability of assertions is more important than their implications; and (3) reviewers judge credibility rather than feasibility. The recent findings of a number of tasks, some selected using this process, are discussed. Of the 14 tasks included, six reached null conclusions, four remain unresolved, and four have opportunities for sequels. A dominant theme with the sequels is research about the properties of space, inertial frames, and the quantum vacuum.
Efficient Orbit Integration by Manifold Correction Methods
Authors: FUKUSHIMA TOSHIO
Published: March 2006

Abstract: Triggered by a desire to investigate, numerically, the planetary precession through a long‐term numerical integration of the solar system, we developed a new formulation of numerical integration of orbital motion named manifold correct on methods. The main trick is to rigorously retain the consistency of physical relations, such as the orbital energy, the orbital angular momentum, or the Laplace integral, of a binary subsystem. This maintenance is done by applying a correction to the integrated variables at each integration step. Typical methods of correction are certain geometric transformations, such as spatial scaling and spatial rotation, which are commonly used in the comparison of reference frames, or mathematically reasonable operations, such as modularization of angle variables into the standard domain [−π, π);. The form of the manifold correction methods finally evolved are the orbital longitude methods, which enable us to conduct an extremely precise integration of orbital motions. In unperturbed orbits, the integration errors are suppressed at the machine epsilon level for an indefinitely long period. In perturbed cases, on the other hand, the errors initially grow in proportion to the square root of time and then increase more rapidly, the onset of which depends on the type and magnitude of the perturbations. This feature is also realized for highly eccentric orbits by applying the same idea as used in KS‐regularization. In particular, the introduction of time elements greatly enhances the performance of numerical integration of KS‐regularized orbits, whether the scaling is applied or not.
Regulation of cardiotrophin-1 expression in mouse embryonic stem cells by HIF-1α and intracellular reactive oxygen species
Authors: Ateghang Bernadette , Wartenberg Maria , Gassmann Max , Sauer Heinrich
Published: March 2006

Cardiomyogenesis in differentiating mouse embryonic stem (ES) cells is promoted by cardiotrophin-1 (CT-1), a member of the IL-6 interleukin superfamily that acts through the tall gp130 cytokine receptor. We show that prooxidants (menadione, hydrogen peroxide) as well as chemical (CoCl2) and physiological (1% O2) hypoxia increased CT-1 as well as HIF-1α protein and mRNA expression in embryoid bodies, indicating that CT-1 expression is regulated by reactive oxygen species (ROS) and hypoxia. Treatment with either prooxidants or chemical hypoxia increased gp130 phosphorylation and protein expression of NADPH oxidase subunits p22-phox, p47-phox, p67-phox, as well as Nox1 and Nox4 mRNA. Consequently, inhibition of NADPH oxidase activity by diphenylen iodonium chloride (DPI) and apocynin abolished prooxidant- and chemical hypoxia-induced upregulation of CT-1. Prooxidants and chemical hypoxia activated ERK1,2, JNK and p38 as well as PI3-kinase. The proxidant- and CoCl2-mediated upregulation of CT-1 was significantly inhibited in the presence of the ERK1,2 antagonist UO126, the JNK antagonist SP600125, the p38 antagonist SKF86002, the PI3-kinase antagonist LY294002, the Jak-2 antagonist AG490 as well as in the presence of free radical scavengers. Moreover, developing embryoid bodies derived from HIF-1α-/- ES cells lack cardiomyogenesis, and prooxidants as well as chemical hypoxia failed to upregulate CT-1 expression. Our results demonstrate that CT-1 expression in ES cells is regulated by ROS and HIF-1α and imply a crucial role of CT-1 in the survival and proliferation of ES-cell-derived cardiac cells.
Bloodstream formTrypanosoma bruceidepend upon multiple metacaspases associated with RAB11-positive endosomes
Authors: Helms Matthew J. , Ambit Audrey , Appleton Paul , Tetley Laurence , Coombs Graham H. , Mottram Jeremy C.
Published: March 2006

Trypanosoma brucei possesses five metacaspase genes. Of these, MCA2 and MCA3 are expressed only in the mammalian bloodstream form of the parasite, whereas MCA5 is expressed also in the insect procyclic form. Triple RNAi analysis showed MCA2, MCA3 and MCA5 to be essential in the bloodstream form, with parasites accumulating pre-cytokinesis. Nevertheless, triple null mutants (Δmca2/3Δmca5) could be isolated after sequential gene deletion. Thereafter, Δmca2/3Δmca5 mutants were found to grow well both in vitro in culture and in vivo in mice. We hypothesise that metacaspases are essential for bloodstream form parasites, but they have overlapping functions and their progressive loss can be compensated for by activation of alternative biochemical pathways. Analysis of Δmca2/3Δmca5 revealed no greater or lesser susceptibility to stresses reported to initiate programmed cell death, such as treatment with prostaglandin D2. The metacaspases were found to colocalise with RAB11, a marker for recycling endosomes. However, variant surface glycoprotein (VSG) recycling processes and the degradation of internalised anti-VSG antibody were found to occur similarly in wild type, Δmca2/3Δmca5 and triple RNAi induced parasites. Thus, the data provide no support for the direct involvement of T. brucei metacaspases in programmed cell death and suggest that the proteins have a function associated with RAB11 vesicles that is independent of known recycling processes of RAB11-positive endosomes.
Radial spoke proteins ofChlamydomonasflagella
Authors: Yang Pinfen , Diener Dennis R. , Yang Chun , Kohno Takahiro , Pazour Gregory J. , Dienes Jennifer M. , Agrin Nathan S. , King Stephen M. , Sale Winfield S. , Kamiya Ritsu , Rosenbaum Joel L. , Witman George B.
Published: March 2006

The radial spoke is a ubiquitous component of `9+2' cilia and flagella, and plays an essential role in the control of dynein arm activity by relaying signals from the central pair of microtubules to the arms. The Chlamydomonas reinhardtii radial spoke contains at least 23 proteins, only 8 of which have been characterized at the molecular level. Here, we use mass spectrometry to identify 10 additional radial spoke proteins. Many of the newly identified proteins in the spoke stalk are predicted to contain domains associated with signal transduction, including Ca2+-, AKAP- and nucleotide-binding domains. This suggests that the spoke stalk is both a scaffold for signaling molecules and itself a transducer of signals. Moreover, in addition to the recently described HSP40 family member, a second spoke stalk protein is predicted to be a molecular chaperone, implying that there is a sophisticated mechanism for the assembly of this large complex. Among the 18 spoke proteins identified to date, at least 12 have apparent homologs in humans, indicating that the radial spoke has been conserved throughout evolution. The human genes encoding these proteins are candidates for causing primary ciliary dyskinesia, a severe inherited disease involving missing or defective axonemal structures, including the radial spokes.
IFN-type-I-mediated signaling is regulated by modulation of STAT2 nuclear export
Authors: Frahm Thomas , Hauser Hansjörg , Köster Mario
Published: March 2006

Signaling through the IFN type I receptor is mediated by assembly of the ISGF3 complex consisting of STAT1, STAT2 and IRF9. Whereas STAT1 is instrumentalized by many cytokines, STAT2 is specifically used by type I IFNs. Here, we report that the main regulatory mechanism of nuclear accumulation of STAT2 is nuclear export. We determined the kinetics of nucleocytoplasmic shuttling of STAT2 in living cells. In the absence of IFN, a virtually exclusive cytoplasmic localisation of STAT2 can be detected. Nevertheless, STAT2 is permanently and rapidly shuttling between the cytoplasm and the nucleus. The steady-state localization is explained by a very efficient nuclear export. Our studies indicate that at least two pathways (one of which is CRM1-dependent, the other not yet identified) are responsible for clearing the nucleus from STAT2. The constitutive nucleocytoplasmic shuttling of STAT2 does neither depend on the presence of IRF9 or STAT1, nor does it require tyrosine phosphorylation. Upon treatment with IFN type I, nuclear export of STAT2 is completely abolished in cells used within this study, whereas nuclear import is functioning. This explains the observed nuclear accumulation of STAT2. We have identified a region in the C-terminus of STAT2 that is essential for its almost exclusively cytoplasmic localization in the absence of IFN and responsible for CRM1-specific export.

In comparative studies we show that nucleocytoplasmic shuttling of STAT2 is significantly different from that of STAT1. STAT1 is also shuttling in the absence of IFN, but the exchange rate in unstimulated cells is more than ten times lower. We further show that the latent STAT2 protein has stronger intrinsic nuclear-export activity than STAT1. Together, these observations lead to a model for IFN-type-I-induction in which the receptor-mediated heterodimerization overcomes the slow nuclear import of STAT1 and blocks the strong STAT2 export activity that leads to the accumulation of both signal transducers in the nucleus.
The Catalytic Diels-Alder Reaction Using Combined Catalyst System of Diphenyltin Sulfide or Lawesson’s Reagent and Silver Perchlorate
Authors: Mukaiyama Teruaki , Watanabe Kimitoshi , Shiina Isamu
Published: March 2006

Catalytic Diels-Alder reactions between several 1,3-dienes and α,β-unsaturated ketones are effectively promoted by the combined use of diphenyltin sulfide (Ph2Sn=S) and silver perchlorate or Lawesson’s reagent (2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide) and silver perchlorate under mild conditions.
Novel Stereoisomeric Triterpene Dimers, Xuxuarines Aα and Aβ, from Maytenus chuchuhuasca
Authors: Shirota Osamu , Morita Hiroshi , Takeya Koichi , Itokawa Hideji
Published: March 2006

Two novel stereoisomeric triterpene dimers, xuxuarines Aα (1) and Aβ (2), were isolated from a South American medicinal plant, “xuxuá” (Maytenus chuchuhuasca Raymond-Hamet et Colas), and their structures and conformations were elucidated by spectroscopic, chemical evidence and MD calculations.
Syntheses and Redox Properties of Di-, Tri-, Tetra-, and Pentaamines
Authors: Sasaki Shigeru , Iyoda Masahiko
Published: March 2006

A series of di-, tri-, tetra-, and pentaamines were synthesized as precursors for corresponding di-, tri-, tetra-, and penta(aminium radical-cations) by the aryl-N bond formation reaction between aryl iodides and in situ prepared copper amide in refluxing pyridine. Cyclic voltammograms of meta-connected derivatives consisted of irreversible waves which imply side reactions in addition to oxidation to aminium radical-cations.
The Structure of a Metabolite from Leaves of Winter Wheat Inoculated with H2O2
Authors: Takashima Hisanori , Jin Shigeki , Yoshida Midori , Abe Jiro , Murai Akio
Published: March 2006

A metabolite has been isolated from winter wheat leaves inoculated with H2O2 and its structure was elucidated from the spectral data.
ESR of the π-Radical Formed by Photoreduction of Bis(1,2,5-selenadiazolo)-tetracyanoquinodimethane in Methanol. Observation of a Large 77Se Hfs
Authors: Hirayama Masatoshi , Terasaka Toshitaka , Morita Yoichi , Suzuki Takanori , Yamashita Yosiro , Miyashi Tsutomu
Published: March 2006

A large 77Se hfs was observed in the ESR spectrum of a radical generated by photoreduction of the electron acceptor, BSDA-TCNQ(3), with 355 nm laser irradiation in methanol. This spectrum was identified as the anion radical of a proton adduct of 3, which was supported by the MO calculation.
Enhancement Properties of Organic Electroluminescence Device Using Electropolymerized Poly(3-n-octylthiophen) Thin Film
Authors: Osaka Tetsuya , Komaba Shin-ichi , Fujihana Kenichiro , Okamoto Naoki , Kaneko Norihiko
Published: March 2006

By using electropolymerized poly(3-n-octylthiophen) (PAT8) film as a hole transporting layer, the light-emission of an organic electroluminescence layer of poly(N-vinylcarbazole) dip-coating layer doped with 2,5-bis(1-naphthyl)-1,3,4-oxadiazole and 3-(2′-benzothiazolyl)-7-diethylaminocoumarin, was remarkably enhanced as compared with the layer without PAT8 layer. The addition of the hole transporting layer made the turn-on bias reduce and the emission intensity increase to be 600 cd m−2.
Highly Stereoselective Synthesis of Both Enantiomers of 2-Methyl-3-Hydroxythioesters by Asymmetric Aldol Reactions Using Similar Types of Chiral Sources Derived from L-Proline
Authors: Shu Kobayashi , Horibe Mineko
Published: March 2006

Both enantiomers of 2-methyl-3-hydroxythioesters have been synthesized in chiral tin(II) Lewis acid-mediated aldol reactions of silyl enolate 3 with aldehydes, by simply choosing similar types of chiral sources, 4 and 5, derived from L-proline.
Tropothione S-Sulfide. A New Class of Thiosulfine
Authors: Machiguchi Takahisa , Minoura Mao , Yamabe Shinichi , Minato Tsutomu
Published: March 2006

Tropothione S-sulfide is synthesized from tropone hydrazone with disulfur dichloride in deaerated chloroform at −78 °C. The S-sulfide is detected as an unprecedented [10π + 2π]-type cycloadduct with dimethyl acetylenedicarboxylate.
Reconstitution of Membrane Proteins into Lipid Monolayer. Two-Step Transfer Technique: From Cell to Liposome, from Liposome to Lipid Monolayer
Authors: Glück Guiscard , Okumura Yukihisa , Sunamoto Junzo
Published: March 2006

A direct reconstitution method, possibly under non-denaturing conditions, was developed to study membrane protein-lipid monolayer at the air/water interface. Proteins were first transferred from intact human erythrocytes or ghosts to liposomes, which spontaneously transformed at the air/water interface. Then, by using the wet-bridge method, a stable protein containing monolayer by means of surface pressure/area diagrams was formed that exhibited erythrocyte acetylcholinesterase activity.
Thermodynamic Considerations for the Design of and Ligand Recognition by Molecularly Imprinted Polymers
Authors: Nicholls Ian A
Published: March 2006

Thermodynamic considerations relevant to molecularly imprinted polymer (MIP) preparation and non-covalent interaction based ligand recognition are presented. Together with the description of a semi-quantitative approach to recognition analysis, adapted for MIPs, thermodynamically based principles for MIP design are discussed.
One-Shot Synthesis of Polyester Macromonomer by Enzymatic Ring-Opening Polymerization of Lactone in the Presence of Vinyl Ester
Authors: Uyama Hiroshi , Kikuchi Hirofumi , Kobayashi Shiro
Published: March 2006

Polyester macromonomers bearing a polymerizable methacryloyl or 10-undecenolyl group at the chain end were synthesized by the lipase-catalyzed ring-opening polymerization of 12-dodecanolide in the presence of a vinyl ester having the corresponding polymerizable group.