bluuebunny/crossref_metadata_2025 huggingface dataset:
Probing Semiconductor-Semiconductor Interfaces
Authors: Bauer Robert S. , Margaritondo Giorgio
Published: January 2008

Almost every aspect of modern life is affected by a practical result of research in condensed matter physics: semiconductor devices. The performance of these solid-state devices is determined largely by the physical properties of the interfaces within them. It is the properties of interfaces in rectifying metal-semiconductor junctions, ohmic contacts, metal-oxide-semiconductor structures and p-n junctions, for example, that determine the performance of such devices as infrared detectors, microwave amplifiers, computer processors and laser diodes, respectively.
Icosahedral Boron-Rich Solids
Authors: Emin David
Published: January 2008

Boron-rich molecules and solids hold a special place within chemistry. They do not follow the general bonding rules we are taught in chemistry classes. For example, some boron-rich solids are composed of 12-atom clusters of boron atoms in which each boron atom resides on a vertex of an icosahedron. These solids are very stable refractory materials with melting temperatures up to 2400 °C—a thousand degrees greater than silicon's. Beyond this, they possess numerous novel structural, electronic and thermal properties that are not only interesting but useful.
Computer Modeling in Physical Oceanography from the Global Circulation to Turbulence
Authors: Holland William R. , McWilliams James C.
Published: January 2008

In a computational science, there can come a time when enough raw computational power is available to lift the science to a new level of fundamental understanding. Particularly in various subdisciplines of fluid dynamics, the complexity of the physical problems to be solved establishes a benchmark—a minimum need in computer resources. It is only recently that sufficient computing power has become available to allow significant leaps in the understanding of important phenomena. The rapid increase has been extraordinary over the last several decades, with a 10-fold increase in the speed of computations in the 1970s and a 25-fold increase in the 1960s. Today's supercomputer is a thousand times more powerful than those in existence in the early 1960s, when the first ocean model calculations were done.
Physics Literacy
Authors: Schmidt Jeffrey
Published: January 2008

The Bush Administration's emphasis on science and mathematics reflects a new and accelerating feature of modern societies: As the economies of the industrialized countries shift toward high-technology manufacturing and services, the jobs available to new entrants into the work force require higher levels of skill and education than ever before. Projections are that over half of the jobs available by the end of the decade in the United States will require some education beyond high school, compared with 42% of currently available jobs. There will be fewer jobs for the poorly educated high school graduate and fewer still for the 25–30% of students who drop out of high school without graduating.
Superconductivity and Other Macroscopic Quantum Phenomena
Authors: Bardeen John
Published: January 2008

As first suggested by Fritz London, superconductivity and superfluid flow in liquid helium are macroscopic quantum phenomena. They depend on the fact that the energy states of even macroscopic objects, although closely spaced, are discrete, and on the statistical mechanics of systems made up of identical particles. The electrons in a superconducting metal, with a spin of one-half, obey Fermi-Dirac statistics and the exclusion principle. Helium atoms of isotopic mass 4 obey Einstein-Bose statistics, in which there can be many particles in the same quantum state, as is the case with photons, the quanta of radiation, if they are regarded as particles.
Nanofabrication
Authors: Smith Henry I. , Craighead Harold G.
Published: January 2008

A decade ago the fabrication and study of electron devices whose smallest features were just under 1 micron in size represented the forefront of the field. Today that forefront has moved down an order of magnitude to 100 nanometers, engendering new terminology based on the prefix nano, from the Greek word for dwarf: “nanoscale devices,” “nanolithography,” “nanofabrication.”
A New Class of Pulsars
Authors: Backer Donald C. , Kulkarni Shrinivas R.
Published: January 2008

In 1939, seven years after the discovery of the neutron, nuclear physicists constructed the first models of a “neutron star.” Stable results were found with masses comparable to the Sun's and radii of about 10 km.
Electron Holography: A New View of the Microscopic
Authors: Tonomura Akira
Published: January 2008

Now that coherent field-emission electron beams are available, one can exploit the wave nature of free electrons to do holography on the atomic scale.
Chemical Dynamics in Solution
Authors: Fleming Graham R. , Wolynes Peter G.
Published: January 2008

The majority of reactions carried out by chemists take place in liquid solutions. Only within the last 10-15 years, however, has it become possible to study such reactions in molecular detail.
Turbulence: Challenges for Theory and Experiment
Authors: Frisch Uriel , Orszag Steven A.
Published: January 2008

Research in macroscopic classical physics, such as fluid dynamics or aspects of condensed matter physics, continues to confront baffling challenges that are by no means less demanding than those at the post-Newtonian frontiers of physics that have been explored since the beginning of this century. This is so even though the basic equations of macroscopic classical physics are known—indeed, have been known for centuries in many cases. Chaos and nonlinear dynamics are examples of the topics that pose new challenges to our understanding of macroscopic classical systems. Turbulence, a phenomenon related to but distinct from chaos, and having strong roots in engineering, has been increasingly in the focus of physics research in recent years.
Heisenberg, Goudsmit and the German Atomic Bomb
Authors: Walker Mark
Published: January 2008

The question of whether German scientists would have been willing to make atomic bombs for Adolf Hitler has excited persistent interest. Just why this is so is a topic I have explored elsewhere. Here, I contend that the roots of the controversy about the role of the German scientists are to be found mainly in the period immediately after the war, not in the war itself.
Studies of the Earth's Deep Interior: Goals and Trends
Authors: Lay Thorne , Ahrens Thomas J. , Olson Peter , Smyth Joseph , Loper David
Published: January 2008

The deep interior of planet Earth has long fascinated philosophers, scientists and fantasy writers, yet it remains inaccessible to direct scrutiny and thus largely enigmatic. Romantic notions about the interior are provocative, with crystal-filled chambers and pitchfork-bearing devils. However, the more scientifically based visions are just as alluring.
Getting Physics into the Paper
Authors: Petit Charles
Published: January 2008

Few newspaper reporters have a formal grounding in physics. Yet most who cover hard science rate physics as among the most enjoyable and rewarding parts of the beat.
Squeezed and Antibunched Light
Authors: Teich Malvin C. , Saleh Bahaa E. A.
Published: January 2008

As a direct result of the quantum nature of electromagnetic radiation, all forms of light exhibit inherent and unavoidable random fluctuations. Because these fluctuations reveal information about the nature of light and the underlying processes that generate it, they have received considerable attention since the time of Einstein. But they are also a source of noise that limits the accuracy with which information can be transmitted by a beam of light. Although experiments often still struggle with instrumental noise, some are quickly approaching the measurement limits set by the quantum-statistical nature of light. With the help of new techniques to “squeeze” the uncertainty of light, researchers can now conduct experiments with greater precision than possible with laser light. The generation of various forms of squeezed light in recent years has raised hopes for its application to such diverse areas as gravity-wave detection based on optical interferometry and reduced-error lightwave communications.
AIP in 1989: An Annual Report
Authors: Ford Kenneth W.
Published: January 2008

A paradox of physics in these times is that the public is increasingly interested in reading about it while young people in schools and colleges are less and less interested in studying it. A 1989 AIP report, Who Takes Science?, gives disheartening statistics on the study of mathematics and science by high school students. Another AIP report published in 1989, Enrollments and Degrees, shows that after a decade in which the number of bachelor's degrees awarded in physics was inching slowly back upward toward its 1970 level, that number turned down again.
Investing in the Future: How Much Governments Pay for Academic Research
Authors: Irvine John , Martin Ben R. , Isard Phoebe
Published: January 2008

It is conventional wisdom that scientific research is crucial to the wealth of nations. This view has influenced political thinking since Vannevar Bush, the MIT computer engineer who coordinated US defense research in World War II, first expounded it in his 1945 book, Science, the Endless Frontier. In it he wrote: “New products and processes are founded on new principles and conceptions which, in turn, are developed by research in the purest realms of science.” This has come to mean that the technological innovations so vital to economic competitiveness frequently depend upon scientific discoveries that usually emerge from the research base fixed firmly in universities, government laboratories and some large corporate organizations. Indeed, the connection of research and development with economic and social advancement is now a political maxim the world's great industrial nations (and those that aspire to greatness) have adopted, although sometimes more in principle than in practice.
Neutrino and Dark-Matter Detection at Low Temperature
Authors: Stodolsky Leo
Published: January 2008

It is with shock, and with new respect for the subtleties of condensed matter physics, that the noninitiate (such as I was) first realizes that at low temperatures a microscopic energy—like that associated with a single atom—can be enough to seriously affect the state of a macroscopic body.
Special Issue: Pre-College Education
Authors: Swartz Clifford
Published: January 2008

There appears to be a great stir in the land concerning our science education system. Eminent committees have warned us that our nation is at risk. Congress has given extra money to the NSF specifically earmarked for precollege education. Many school districts and even states are experimenting with drastic revisions of how and when physics is taught in the upper grades. Physicists are taking part in some, but not all, of these projects.
The Materials of Physics Instruction
Authors: Salinger Gerhard L.
Published: January 2008

Since the middle 1980s there has been great ferment in the US over the need to reform education in science, mathematics and technology. Reports such as “A Nation at Risk” and international comparisons of achievement in mathematics and science gave impetus to efforts to develop new materials and improve the education of both in-service and pre-service teachers so that they can better educate the students who will become our nation's scientists, mathematicians, engineers, technicians, workers and voting citizens.
The New Ground-Based Optical Telescopes
Authors: Martin Buddy , Hill John M. , Angel Roger
Published: January 2008

We are in a period of rapid improvement in the capability of telescopes. Great strides are being taken to improve angular resolution, to increase sensitivity at all wavelengths and to make the most efficient use of wide-field images. The technical challenges involved in such development are great, for not only do we need mirror surfaces much larger than what we have used before, but we require higher image quality. It has recently become clear that the best mountaintop observatory sites occasionally deliver images as sharp as 0.3 arcsecond, an image quality that many existing telescopes cannot maintain.
Adaptive Optics and Interferometry
Authors: Beichman Charles A. , Ridgway Stephen
Published: January 2008

During the last 350 years, astronomers have improved the sensitivity of their observations by a factor of almost a billion by using larger telescopes and better detectors. At optical wavelengths, however, there has been little improvement in angular resolution since Galileo's time. Until very recently, atmospheric turbulence limited the resolution of astronomical observations with even the largest telescopes at the best sites to around 0.5”. Astronomy is on the verge of realizing the promise of two new techniques that will improve the limiting resolution of optical and infrared observations by factors of tens or even thousands.
Soviet Science in Danger
Authors: Feinberg Evgenii L.
Published: January 2008

Fundamental science in the former Soviet Union faces dangers that could lead to catastrophe. The situation for fundamental science is different from those confronting applied science in general and Soviet military technology in particular. Applied science has its own ways to accommodate itself to a market economy, while the proliferation of Soviet nuclear technology is a special problem that has attracted the attention of politicians throughout the world. I will leave such other fields aside and instead speak only on fundamental science, which seems helpless.
The Nobel Prizes at 90
Authors: Lubkin Gloria B.
Published: January 2008

When the Royal Swedish Academy of Sciences announced on 14 October that Georges Charpak of CERN is the winner of the 1992 Nobel Prize in Physics “for his invention and development of particle detectors, in particular the multiwire proportional chamber,” the academy was continuing the process begun in 1901, when the physics prize was awarded to Wilhelm Röntgen for the discovery of x rays. Over the ensuing nine decades, the selection process has been remarkable for its secrecy, the care with which it is done, and the high quality of the research honored.
Creativity and Big Science
Authors: Heilbron John L.
Published: January 2008

Creativity and big science may sit uneasily together. Creativity is considered good in any amount; I do not recall ever hearing anyone complain of having more of it than he or she wanted. Big science, however, has its detractors. Some fret that it consumes resources better devoted to little science; others, that it routinizes work, bureaucratizes laboratory life and, to say the worst, suppresses creativity.
Special Issue: The Physics of Digital Color
Authors: Roetling Paul
Published: January 2008

Images have always been the best mode of communication between people, but technologies such as the typewriter have long made text easier to reproduce than images. As a result of two separate, but closely related, revolutions in technology, however, digital color images are now becoming commonplace. First, the practical use of digital technology in imaging could not have come about without the tremendous gains made over the past 20 years or so in the speed and capability of digital computers and peripherals, coupled with continuous reductions in cost for equivalent performance. Second, in the last few decades our understanding of the physics and chemistry underlying the technologies of scanning, displaying and printing color images has vastly improved; at the same time we have seen tremendous developments in related manufacturing techniques.
Color in Electronic Displays
Authors: Tannas Lawrence E.
Published: January 2008

When historians judge the 20th century, they may conclude that one of its most important technical accomplishments was the electronic color video display. Certainly there have been many other notable inventions, such as the transistor, the computer and the video camera, but these are all parts used to make electronic images. Electronic images are still many times more expensivethan other forms of images, and they are limited in resolution. Nonetheless, they have an advantage over all other forms of images that completely eclipses the limitations: the speed and ease with which they can be captured, distributed, stored, retrieved, edited and displayed in real time. One can sit in Los Angeles and see the finish of an Olympic event in Barcelona with nearly the same sense of reality that someone actually in the grandstands experiences. Some television viewers feel they even have better coverage of the event because of theuse of stop action, replay, zoom and multiple camera angles. When such an event is displayed with the resolution of high-definition television and with stereo sound, one can easily imagine being there. In this and many other ways, electronic images are helping to propel the human race into the information age.
The Dynamical Evidence for Dark Matter
Authors: Tremaine Scott
Published: January 2008

Almost all of our information about the universe beyond Earth comes from photons—visible photons from stars, xray photons from hot plasmas, radio photons from the 21-cm hyperfine transition in hydrogen, microwave photons from the cosmic background radiation and so forth.
A German Professor's Trip to El Dorado
Authors: Boltzmann Ludwig
Published: January 2008

Having been to Constantinople, Athens, Smyrna and Algiers, and several times to America, I've been urged repeatedly to publish accounts of some of my travels. But it all seemed to me too insignificant. My recent trip to California, however, was something quite exquisite. So I will venture a little chat about it.
Issues and Opportunities in Materials Research
Authors: Langer James
Published: January 2008

In the fall of 1989 the National Research Council issued a major report on materials science and engineering, known more familiarly as the Chaudhari-Flemings report (after Praveen Chaudhari and Merton Flemings) or simply the MS&E report. This was followed in 1990 by a series of regional meetings in four different parts of the US involving hundreds of participants from industry, academia and government. The results of those meetings were summarized in a 1991 proposal for a “National Agenda” in materials, addressed to the Office of Science and Technology Policy. In turn, this proposal has led to a Presidential initiative for fiscal year 1993 entitled Advanced Materials and Processing.
Defects and Superconductivity in Layered Cuprates
Authors: Raveau Bernard
Published: January 2008

After the discovery of superconductivity at 40 K in cuprates by Georg Bednorz and Alex Müller in 1986, many researchers became involved in the synthesis of new higher-temperature superconductors. I believe that many of them failed in this quest simply because they did not realize that the crystal chemistry of such materials is extremely complicated. By the following spring, of course, groups all over the world were fabricating new superconducting cuprates of yttrium, bismuth and thallium that allowed critical temperatures to exceed the all-important 77-K boiling point of liquid nitrogen. But because of the complex crystal chemistry involved, it will take a long time to optimize the superconducting properties of these cuprates for the development of useful superconducting wires. Thin films of superconducting cuprates, by contrast, are already quite close to being commercially available for SQUIDS and microwave applications.
An Extraordinary Man: Reflections on John Bardeen
Authors: Pines David
Published: January 2008

I met John Bardeen in the spring of 1950, when he was still at Bell Labs and I was a graduate student in physics at Princeton. That semester John came once a week to teach a seminar on the physics of semiconductors. Although I was in the midst of my thesis research, I regularly attended his lectures, which I remember as being clear, informative and low key. (The notes for this seminar formed the basis of EE-PHYS 435, Bardeen's famous electrical engineering course at Illinois, described in the article by Nick Holonyak on page 36.)
Physical modeling of cell geometric order in an epithelial tissue
Authors: Hilgenfeldt Sascha , Erisken Sinem , Carthew Richard W.
Published: January 2008

In multicellular organisms, cells pack together to form tissues of intricate and well defined morphology. How such cell-packing geometries arise is an important open question in biology, because the functionality of many differentiated tissues depends on their reliable formation. We show that combining adhesive forces due to
E
- and
N
-cadherin with a quantitative description of cell membrane elasticity in an interfacial energy model explains not only the qualitative neighbor relations, but also the detailed geometry of a tissue. The characteristic cellular geometries in the eyes of both wild-type
Drosophila
and genetic mutants are accurately reproduced by using a fixed set of few, physically motivated parameters. The model predicts adhesion strengths in the eye epithelium, quantifies their role relative to membrane elasticity, and reveals how simple minimization of interfacial energy can give rise to complex geometric patterns of important biological functionality.
Conformational thermostabilization of the β1-adrenergic receptor in a detergent-resistant form
Authors: Serrano-Vega Maria J. , Magnani Francesca , Shibata Yoko , Tate Christopher G.
Published: January 2008

There are ≈350 non-odorant G protein-coupled receptors (GPCRs) encoded by the human genome, many of which are predicted to be potential therapeutic targets, but there are only two structures available to represent the whole of the family. We hypothesized that improving the detergent stability of these receptors and simultaneously locking them into one preferred conformation will greatly improve the chances of crystallization. We developed a generic strategy for the isolation of detergent-solubilized thermostable mutants of a GPCR, the β1-adrenergic receptor. The most stable mutant receptor, βAR-m23, contained six point mutations that led to an apparent
T
m
21°C higher than the native protein, and, in the presence of bound antagonist, βAR-m23 was as stable as bovine rhodopsin. In addition, βAR-m23 was significantly more stable in a wide range of detergents ideal for crystallization and was preferentially in an antagonist conformation in the absence of ligand.
Evigan: a hidden variable model for integrating gene evidence for eukaryotic gene prediction
Authors: Liu Qian , Mackey Aaron J. , Roos David S. , Pereira Fernando C. N.
Published: January 2008

Motivation: The increasing diversity and variable quality of evidence relevant to gene annotation argues for a probabilistic framework that automatically integrates such evidence to yield candidate gene models.

Results: Evigan is an automated gene annotation program for eukaryotic genomes, employing probabilistic inference to integrate multiple sources of gene evidence. The probabilistic model is a dynamic Bayes network whose parameters are adjusted to maximize the probability of observed evidence. Consensus gene predictions are then derived by maximum likelihood decoding, yielding n-best models (with probabilities for each). Evigan is capable of accommodating a variety of evidence types, including (but not limited to) gene models computed by diverse gene finders, BLAST hits, EST matches, and splice site predictions; learned parameters encode the relative quality of evidence sources. Since separate training data are not required (apart from the training sets used by individual gene finders), Evigan is particularly attractive for newly sequenced genomes where little or no reliable manually curated annotation is available. The ability to produce a ranked list of alternative gene models may facilitate identification of alternatively spliced transcripts. Experimental application to ENCODE regions of the human genome, and the genomes of Plasmodium vivax and Arabidopsis thaliana show that Evigan achieves better performance than any of the individual data sources used as evidence.

Availability: The source code is available at http://www.seas.upenn.edu/~strctlrn/evigan/evigan.html

Contact:  qianliu@seas.upenn.edu
Stamen Abscission Zone Transcriptome Profiling Reveals New Candidates for Abscission Control: Enhanced Retention of Floral Organs in Transgenic Plants Overexpressing ArabidopsisZINC FINGER PROTEIN2
Authors: Cai Suqin , Lashbrook Coralie C.
Published: January 2008

Organ detachment requires cell separation within abscission zones (AZs). Physiological studies have established that ethylene and auxin contribute to cell separation control. Genetic analyses of abscission mutants have defined ethylene-independent detachment regulators. Functional genomic strategies leading to global understandings of abscission have awaited methods for isolating AZ cells of low abundance and very small size. Here, we couple laser capture microdissection of Arabidopsis thaliana stamen AZs and GeneChip profiling to reveal the AZ transcriptome responding to a developmental shedding cue. Analyses focus on 551 AZ genes (AZ551) regulated at the highest statistical significance (P ≤ 0.0001) over five floral stages linking prepollination to stamen shed. AZ551 includes mediators of ethylene and auxin signaling as well as receptor-like kinases and extracellular ligands thought to act independent of ethylene. We hypothesized that novel abscission regulators might reside in disproportionately represented Gene Ontology Consortium functional categories for cell wall modifying proteins, extracellular regulators, and nuclear-residing transcription factors. Promoter-β-glucuronidase expression of one transcription factor candidate, ZINC FINGER PROTEIN2 (AtZFP2), was elevated in stamen, petal, and sepal AZs. Flower parts of transgenic lines overexpressing AtZFP2 exhibited asynchronous and delayed abscission. Abscission defects were accompanied by altered floral morphology limiting pollination and fertility. Hand-pollination restored transgenic fruit development but not the rapid abscission seen in wild-type plants, demonstrating that pollination does not assure normal rates of detachment. In wild-type stamen AZs, AtZFP2 is significantly up-regulated postanthesis. Phenotype data from transgene overexpression studies suggest that AtZFP2 participates in processes that directly or indirectly influence organ shed.
Elucidation of the Final Reactions of DIMBOA-Glucoside Biosynthesis in Maize: Characterization ofBx6andBx7
Authors: Jonczyk Rafal , Schmidt Holger , Osterrieder Anne , Fiesselmann Andreas , Schullehner Katrin , Haslbeck Martin , Sicker Dieter , Hofmann Diana , Yalpani Nasser , Simmons Carl , Frey Monika , Gierl Alfons
Published: January 2008

Benzoxazinoids were identified in the early 1960s as secondary metabolites of the grasses that function as natural pesticides and exhibit allelopathic properties. Benzoxazinoids are synthesized in seedlings and stored as glucosides (glcs); the main aglucone moieties are 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one (DIBOA) and 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA). The genes of DIBOA-glc biosynthesis have previously been isolated and the enzymatic functions characterized. Here, the enzymes for conversion of DIBOA-glc to DIMBOA-glc are identified. DIBOA-glc is the substrate of the dioxygenase BENZOXAZINLESS6 (BX6) and the produced 2,4,7-trihydroxy-2H-1,4-benzoxazin-3-(4H)-one-glc is metabolized by the methyltransferase BX7 to yield DIMBOA-glc. Both enzymes exhibit moderate K  m values (below 0.4 mm) and k  cat values of 2.10 s−1 and 0.25 s−1, respectively. Although BX6 uses a glucosylated substrate, our localization studies indicate a cytoplasmic localization of the dioxygenase. Bx6 and Bx7 are highest expressed in seedling tissue, a feature shared with the other Bx genes. At present, Bx6 and Bx7 have no close relatives among the members of their respective gene families. Bx6 and Bx7 map to the cluster of Bx genes on the short arm of chromosome 4.
Indole-3-Acetonitrile Production from Indole Glucosinolates Deters Oviposition byPieris rapae
Authors: de Vos Martin , Kriksunov Ksenia L. , Jander Georg
Published: January 2008

Like many crucifer-specialist herbivores, Pieris rapae uses the presence of glucosinolates as a signal for oviposition and larval feeding. Arabidopsis thaliana glucosinolate-related mutants provide a unique resource for studying the in vivo role of these compounds in affecting P. rapae oviposition. Low indole glucosinolate cyp79B2 cyp79B3 mutants received fewer eggs than wild type, confirming prior research showing that indole glucosinolates are an important oviposition cue. Transgenic plants overexpressing epithiospecifier protein, which shifts glucosinolate breakdown toward nitrile formation, are less attractive to ovipositing P. rapae females. Exogenous application of indol-3-ylmethylglucosinolate breakdown products to cyp79B2 cyp79B3 mutants showed that oviposition was increased by indole-3-carbinol and decreased by indole-3-acetonitrile (IAN). P. rapae larvae tolerate a cruciferous diet by using a gut enzyme to redirect glucosinolate breakdown toward less toxic nitriles, including IAN, rather than isothiocyanates. The presence of IAN in larval regurgitant contributes to reduced oviposition by adult females on larvae-infested plants. Therefore, production of nitriles via epithiospecifier protein in cruciferous plants, which makes the plants more sensitive to generalist herbivores, may be a counter-adaptive mechanism for reducing oviposition by P. rapae and perhaps other crucifer-specialist insects.
Arabidopsis Stromal 70-kD Heat Shock Proteins Are Essential for Plant Development and Important for Thermotolerance of Germinating Seeds
Authors: Su Pai-Hsiang , Li Hsou-min
Published: January 2008

The 70-kD heat shock proteins (Hsp70s) have been shown to be important for protein folding, protein translocation, and stress responses in almost all organisms and in almost all subcellular compartments. However, the function of plastid stromal Hsp70s in higher plants is still uncertain. Genomic surveys have revealed that there are two putative stromal Hsp70s in Arabidopsis thaliana, denoted cpHsc70-1 (At4g24280) and cpHsc70-2 (At5g49910). In this study, we show that cpHsc70-1 and cpHsc70-2 could indeed be imported into the chloroplast stroma. Their corresponding T-DNA insertion knockout mutants were isolated and designated as Δcphsc70-1 and Δcphsc70-2. No visible phenotype was observed in the Δcphsc70-2 mutant under normal growth conditions. In contrast, Δcphsc70-1 mutant plants exhibited variegated cotyledons, malformed leaves, growth retardation, and impaired root growth, even though the protein level of cpHsc70-2 was up-regulated in the Δcphsc70-1 mutant. After heat shock treatment of germinating seeds, root growth from Δcphsc70-1 seeds was further impaired, indicating that cpHsc70-1 is important for thermotolerance of germinating seeds. No Δcphsc70-1 Δcphsc70-2 double mutant could be obtained, suggesting that the Δcphsc70 double knockout was lethal. Genotype analyses of F1 seedlings from various crosses indicated that double-knockout mutation was lethal to the female gametes and reduced the transmission efficiency of the male gametes. These results indicate that cpHsc70s are essential for plant development and the two cpHsc70s most likely have redundant but also distinct functions.
Tailoring the Specificity of a Plant Cystatin toward Herbivorous Insect Digestive Cysteine Proteases by Single Mutations at Positively Selected Amino Acid Sites
Authors: Goulet Marie-Claire , Dallaire Cindy , Vaillancourt Louis-Philippe , Khalf Moustafa , Badri Amine M. , Preradov Andreja , Duceppe Marc-Olivier , Goulet Charles , Cloutier Conrad , Michaud Dominique
Published: January 2008

Plant cystatins, similar to other defense proteins, include hypervariable, positively selected amino acid sites presumably impacting their biological activity. Using 29 single mutants of the eighth domain of tomato (Solanum lycopersicum) multicystatin, SlCYS8, we assessed here the potential of site-directed mutagenesis at positively selected amino acid sites to generate cystatin variants with improved inhibitory potency and specificity toward herbivorous insect digestive cysteine (Cys) proteases. Compared to SlCYS8, several mutants (22 out of 29) exhibited either improved or lowered potency against different model Cys proteases, strongly suggesting the potential of positively selected amino acids as target sites to modulate the inhibitory specificity of the cystatin toward Cys proteases of agronomic significance. Accordingly, mutations at positively selected sites strongly influenced the inhibitory potency of SlCYS8 against digestive Cys proteases of the insect herbivore Colorado potato beetle (Leptinotarsa decemlineata). In particular, several variants exhibited improved potency against both cystatin-sensitive and cystatin-insensitive digestive Cys proteases of this insect. Of these, some variants also showed weaker activity against leaf Cys proteases of the host plant (potato [Solanum tuberosum]) and against a major digestive Cys protease of the two-spotted stinkbug Perillus bioculatus, an insect predator of Colorado potato beetle showing potential for biological control. Overall, these observations suggest the usefulness of site-directed mutagenesis at positively selected amino acid sites for the engineering of recombinant cystatins with both improved inhibitory potency toward the digestive proteases of target herbivores and weaker potency against nontarget Cys proteases in the host plant or the environment.
CENL1Expression in the Rib Meristem Affects Stem Elongation and the Transition to Dormancy inPopulus
Authors: Ruonala Raili , Rinne Päivi L.H. , Kangasjärvi Jaakko , van der Schoot Christiaan
Published: January 2008

We investigated the short day (SD)–induced transition to dormancy in wild-type hybrid poplar (Populus tremula × P. tremuloides) and its absence in transgenic poplar overexpressing heterologous PHYTOCHROME A (PHYA). CENTRORADIALIS-LIKE1 (CENL1), a poplar ortholog of Arabidopsis thaliana TERMINAL FLOWER1 (TFL1), was markedly downregulated in the wild-type apex coincident with SD-induced growth cessation. By contrast, poplar overexpressing a heterologous Avena sativa PHYA construct (P35S:AsPHYA), with PHYA accumulating in the rib meristem (RM) and adjacent tissues but not in the shoot apical meristem (SAM), upregulated CENL1 in the RM area coincident with an acceleration of stem elongation. In SD-exposed heterografts, both P35S:AsPHYA and wild-type scions ceased growth and formed buds, whereas only the wild type assumed dormancy and P35S:AsPHYA showed repetitive flushing. This shows that the transition is not dictated by leaf-produced signals but dependent on RM and SAM properties. In view of this, callose-enforced cell isolation in the SAM, associated with suspension of indeterminate growth during dormancy, may require downregulation of CENL1 in the RM. Accordingly, upregulation of CENL1/TFL1 might promote stem elongation in poplar as well as in Arabidopsis during bolting. Together, the results suggest that the RM is particularly sensitive to photoperiodic signals and that CENL1 in the RM influences transition to dormancy in hybrid poplar.
People management – be bold!
Authors: Smith Ian
Published: January 2008

Purpose

This paper aims to encourage managers in the rapidly changing library and information services environment to be bold in people management.

Design/methodology/approach

The paper outlines four aspects of people management where it is particularly important to be bold: staff selection and recruitment; training development and workplace learning; performance management, and; organisational change.

Findings

The study reveals pointers to good management practice in the four areas which are outlined.

Originality/value

The paper provides useful information for those in people management.
Wa! Thewú wéiacademic librarian
Authors: Liu Anita M.M.
Published: January 2008

Purpose

This paper seeks to examine the integration of the Western concept of dynamic equilibrium andwa, the Eastern concept of harmony, and howwú wéi(maintainingcentrality, hence, stability, in a dynamic environment) is fundamental to the sustainable development of the library system in a harmonious manner.

Design/methodology/approach

The Western concept of self and the Chinese Taoist concepts of change and stability are used to examine the role of the human being – the librarian – in the constantly evolving environment.

Findings

The paper finds that four competing values faced by the librarian are based on the needs to adopt internal focus, external focus, flexibility and control. The four competing values generate issues confronting the academic librarian. Frustration – what challenges and pressures do academic librarians currently face in the university environment specifically? History and destiny – what lessons can the history of libraries in universities give us about their future role in the scholarly community? Constraints – what are the possible environmental barriers which might prevent librarians working dynamically in parallel with or ahead of university “strategists”, to secure their vision as key players in tomorrow's academy? Conflicting forces from library stakeholders are analysed in a competing values model which encompasses the elements of organisation systems and organisational culture.

Originality/value

The competing values framework provides the basis for formulating a research agenda to investigate the central role played by university libraries in the societal development of human‐kind.
Institutional antecedents to research productivity in operations: the US perspective
Authors: Smith Jeffery S. , Fox Gavin L. , “Sunny” Park Sung‐Hee , Lee Lorraine
Published: January 2008

Purpose

The purpose of this paper is to examine the institutional factors that affect the productivity of individuals in the field of operations.

Design/methodology/approach

This study identifies a sample of graduates from PhD programs in operations and utilizes a partial least squares analysis to examine the effect of academic origin, academic affiliation, and advisor productivity on each individual's research productivity.

Findings

The results of the analysis indicate that the productivity of an individual is directly influenced by the aggregate prestige of the institutions where the individual was employed during article publication and indirectly influenced by the prestige of the institution where the individual received the terminal degree. Additionally, differences were found between groups when the sample was divided by focus (operations management (OM) versus operations research (OR). The OM model held the same relationships as the combined model, while the OR model included significant direct effects of academic origin and indirect effects of the advisor's productivity on the individual's productivity.

Originality/value

This research is the first to fully evaluate the institutional antecedents to research productivity of individuals in operations. In doing so, valuable insights are gained as to how to facilitate the success of researchers in operations. Additionally, factors are highlighted that should be considered by institutions looking at hiring freshly minted PhDs. Finally, these results can benefit practitioners when considering working with academics as a source of emerging information or consulting.
Strategic capabilities and internet resources in procurement
Authors: Ordanini Andrea , Rubera Gaia
Published: January 2008

Purpose

This paper seeks to adopt a resource‐based approach to investigate the link between procurement capabilities, internet resources, and performance. It aims to cover two gaps in the operations management literature: the missing links between procurement capabilities and the performance of a firm, and the role of internet resources in shaping such links.

Design/methodology/approach

After the identification of two key capabilities in procurement and the introduction of internet resources, the relationships with performance are empirically tested in a sample of 93 firms in the textile and clothing industry in Italy. Data were analysed using a partial least‐squares technique and main and interaction effects were investigated.

Findings

First, process efficiency and process integration capabilities provide a significant (and equally important) contribution to firm performance, but there are no complementary effects between them. Second, and contrary to expectations, the internet has been found to enhance the effect of process integration capability, but not that of process efficiency capability. Third, a new finding reveals that the internet not only interacts with each of these capabilities in procurement separately, but it also enhances the synergistic effect between them.

Research limitations/implications

The investigation is based on a self‐reported cross‐sectional analysis, and it is specific to a single industry and the procurement of one type of material. Nonetheless, it suggests a number of different implications. Achieving excellence in procurement requires the development of distinct capabilities, because the management of core purchasing activities and the integration of procurement in the supply chain are not complementary. Contrary to common expectations, employing the internet in procurement has little power to reduce transaction costs, although it can be fruitful for improving inter‐functional coordination. The internet can also help in “putting the pieces together” by exploiting the otherwise latent complementary effects between procurement capabilities.

Originality/value

This paper is unique in that it employs a strategic management theory – the resource‐based view – to unpack the mechanisms through which procurement activities contribute to performance. It represents a first response to the call for research into the use of such theoretical frameworks which has recently been made in the operations management literature. The paper also offers the first empirical test of how the internet interacts with existing capabilities in the procurement domain, providing clear guidance on how to exploit its often undervalued potential.
Three outcomes of service recovery
Authors: Johnston Robert , Michel Stefan
Published: January 2008

Purpose

Based on a review of the literature, this paper sets out to suggest that an organisation's service recovery procedures lead to three distinct outcomes; customer, process, and employee recoveries. The objective of the paper is to investigate the impact of service recovery procedures (i.e. the way service recovery is managed and executed) on these three outcomes and their relative impact on an organisation's financial performance.

Design/methodology/approach

A model, linking recovery procedures to the outcomes of recovery and financial performance, is tested using empirical data from a detailed survey of 60 organisations in the UK.

Findings

It would appear that many organisations and academic researchers have focused their efforts on customer recovery and have, to some extent, ignored the potentially higher impact outcomes of process and employee recovery. The main finding was that service recovery procedures have a greater impact on employees and process improvement than on customers. Furthermore, while many organisations appear to be concerned with service recovery few seem to be good at it or gaining the benefits of recovered customers, improved processes or recovered employees.

Research limitations/implications

This paper tries to encourage wider research into the impact of service recovery. The main limitations were sample size and selection.

Practical implications

It challenges the way some organisations have focused their recovery procedures on satisfying or delighting customers and suggests that by doing so they are missing out on substantial benefits. It also suggests that many organisations have a long way to go to develop their recovery procedures.

Originality/value

This work proposes three outcomes of service recovery and finds that the impact of process and employee recoveries may be more significant than customer recovery.
The impact of learning goals on emotional, social, and cognitive intelligence competency development
Authors: Leonard David C.
Published: January 2008

Purpose

The purpose of this research is to empirically examine the efficacy of setting multiple goals targeting complex competencies with a variety of time horizons pursued across a number of years. Most research conducted in the areas of goal setting examines an individual's ability to achieve a single goal targeting a simple skill or behavioral change within a short time period.

Design/methodology/approach

In this longitudinal study competency development is assessed over time periods ranging from nine months to four and half years and examined using both self‐reported change and behavior change demonstrated through critical incident interviews.

Findings

Progress over the study reveals that establishing learning goals is particularly important to the development of competencies. Subjects developed significantly more on competencies for which they set goals than on other competencies. They also demonstrated greater competency development when goals were remembered.

Research limitations/implications

Subjects were studied during a specific life change event – completion of an MBA program. Their particular education environment was designed to support and encourage change. It undoubtedly contributed to their development during the study. Results therefore may not generalize to broader populations. However, the results reveal clear implications for management education in both academic and corporate education settings.

Practical implications

This study highlights important elements in the development process that when included enhance competency development and provide insight into the mechanisms underlying intentional change theory.

Originality/value

The research evaluates the complexity and difficulty involved in competency development. It provides empirical evidence to support goal setting and intentional change theories.
Computational kinematics for robotic manipulators: Jacobian problems
Authors: Altuzarra O. , Salgado O. , Petuya V. , Hernández A.
Published: January 2008

Purpose

This paper aims to provide tools for the complete Jacobian analysis of robotic manipulators of general topology, using a comprehensive velocity equation.

Design/methodology/approach

First, a modelling process is made in order to build the velocity equation using simple constraint equations: i.e. length restriction, relative motion and rigid body constraints. Then the motion space is solved, i.e. the space that spans all feasible motions of the manipulator.

Findings

The velocity equation is comprehensive, i.e. it relates all kinematic variables, not only input and output. The Jacobian related to the comprehensive velocity equation is a square dimensionless matrix. This characteristic has great importance when evaluating manipulability or closeness to singularities. Employing the motion space, any kinematic entity can be studied: i.e. velocities and accelerations of any active/passive joints, screw axis, axodes, and so on. Also a comprehensive singularity analysis can be made.

Research limitations/implications

The approach presented is focused on the kinetostatic analysis of manipulators and, therefore, subjected to rigid body assumption.

Practical implications

The paper presents a proposal of effective codes for engineering analysis of manipulators.

Originality/value

This approach is based on a pure computational kinematic analysis that unifies all kinetostatic analysis for any manipulator topology (i.e. serial, parallel, hybrid manipulators, complex mechanisms, redundant‐or non‐redundant‐actuated). The characteristic Jacobian matrix is dimensionless and provides the means for a complete singularity analysis and an effective use of indicators.