bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel Types of Superconductivity in F-Electron Systems
Authors: Maple M. Brian
Published: January 2008

During the last one and one-half decades, experiments on compounds and alloys of rare earth and actinide elements with partially filled f-electron shells have revealed novel superconducting phenomena. Among these are the reappearance of resistance at a second critical temperature due to the interaction of magnetic moments with conduction electrons, the coexistence of superconductivity and antiferromagnetism, superconductivity induced by magnetic fields and superconductivity due to electrons with large effective masses.
A Celebration of Physics
Authors: Goodwin Irwin
Published: January 2008

The first National Research Council survey of physics, completed in 1966 by a committee headed by George E. Pake of Xerox, consisted of two thin volumes. The second survey was produced in 1972 by another NRC panel, this time under the chairmanship of D. Allan Bromley of Yale University. It filled four books. This month another Research Council committee, under the leadership of William F. Brinkman of Sandia National Laboratory, issues its survey, Physics Through the 1990s, in eight volumes: an overview and seven panel reports covering subfields of physics. (Highlights from the seven reports begin on page 28.) In itself, the expansion of the physics survey is telling. Physics is flourishing—intellectually and experimentally. Brinkman proclaims this in his preface: “These volumes document a physics enterprise that is vital, creative and productive.”
Reports on Subfields of Physics: Nuclear Physics
Authors: Schechter Bruce
Published: January 2008

In the 50 or so years between the discovery of the neutron and the meeting of the Panel on Nuclear Physics of the physics survey committee our understanding of the physical universe has been immeasurably expanded. In its report the panel first reviews the impressive achievements in nuclear physics of the decade passed, then goes on to make recommendations designed to insure continued achievement in the future.
Von Kármán: Fluid Dynamics and Other Things
Authors: Sears William R.
Published: January 2008

It is a pleasure to write about Theodore von Kármán. I am somewhat concerned, however, as I consider the audience for this article, many of whom are also fluid dynamicists: I can imagine quite a few old friends who knew von Kármán—perhaps as well as I—saying, “Oh, that isn't the way it really was.” Well, I can only say that what I am going to write about is the way I remember it. (There must be some kind of “statute of limitations” that says that when you get to a certain age—and I suppose I have—you're entitled to tell it the way you remember it, and let the chips fall where they may.)
Reactive-Ion Etching
Authors: Oehrlein Gottlieb S.
Published: January 2008

Our ability to develop and build ever smaller microelectronic devices depends strongly on the capability to generate a desired device pattern in an image layer (photoresist) by lithography and then to transfer this pattern into the layers of materials of which the device consists. In the past the pattern transfer was almost exclusively accomplished by wet etching. Chemical dissolution of a film region that had to be removed took place in a suitable solvent. Although the wet etching processes stop precisely at a chemically different underlying layer, they typically have isotropic etch characteristics, which cost the researcher control over critical lateral dimensions. Such a tradeoff is not acceptable in the manufacture of micron- and submicron-scale devices, and wet, solution-based etching techniques were replaced in the late 1970s by dry, directional etching processes using plasmas or ion beams. Figure 1 shows a plasma-based dry etching system at IBM. In dry etching processes, surface atoms are removed via momentum transfer from bombarding, directed ions (physical sputtering), thus achieving a directional etch.
VLSI Technology and Dielectric Film Science
Authors: Feigl Frank J.
Published: January 2008

An important reason for the dominance of crystal silicon in electronics is the quality of its natural oxide. Silicon dioxide forms a glass film on the crystal, with an atomically abrupt interface between them. At the ordinary operating temperatures of the devices, it is mechanically stable, electrically insulating and chemically protective. Germanium and gallium arsenide, materials whose inherent electrical properties are superior to those of silicon, are at a disadvantage because of the inferior properties of their oxides: Germanium dioxide is water soluble, and the oxidation of gallium arsenide produces metallic precipitates.
Compound-Semiconductor Transistors
Authors: Eastman Lester F.
Published: January 2008

One route to faster electronics is faster electrons, for the switching speed of the transistors that lie at the heart of most electronic circuits is limited by the velocity of the electrons themselves. Electrons in compound semiconducting materials such as gallium arsenide move with much higher velocities under applied electric fields than do electrons in silicon. This and other properties of semiconducting compounds are opening the way for new devices, including logic circuits (figure 1) that operate at higher speeds, microwave devices that operate at higher frequencies and circuits that interface easily with optical fibers.
Soviet Space Science
Authors: Sagdeev Roald Z.
Published: January 2008

The physicist Lev Artsimovich once defined science as the way scientists satisfy their curiosity at the expense of the nation. Space studies are in no way the cheapest source of satisfaction, so making decisions about the main trends of space science and about the priorities of these studies is a heavy responsibility.
Earth, Air, Radon and Home
Authors: Nero Anthony
Published: January 2008

Our use of nuclear technology for medicine, energy and weapons during this century has led to growing awareness of the potentially harmful effects of radiation. Many people are even aware that exposures from weapons testing and from normally operating nuclear power plants have been far below those from the Earth's natural radioactivity and cosmic rays. The only human activities that routinely cause doses approaching those from natural radiation are medical uses of radiation for diagnosis or therapy.
Is Pictorial Perception Robust? The Effect of the Observer Vantage Point on the Perceived Depth Structure of Linear-Perspective Images
Authors: Todorović Dejan
Published: January 2008

Every image of a scene produced in accord with the rules of linear perspective has an associated projection centre. Only if observed from that position does the image provide the stimulus which is equivalent to the one provided by the original scene. According to the perspective-transformation hypothesis, observing the image from other vantage points should result in specific transformations of the structure of the conveyed scene, whereas according to the vantage-point compensation hypothesis it should have little effect. Geometrical analyses illustrating the transformation theory are presented. An experiment is reported to confront the two theories. The results provide little support for the compensation theory and are generally in accord with the transformation theory, but also show systematic deviations from it, possibly due to cue conflict and asymmetry of visual angles.
High field gradient targeting of magnetic nanoparticle-loaded endothelial cells to the surfaces of steel stents
Authors: Polyak Boris , Fishbein Ilia , Chorny Michael , Alferiev Ivan , Williams Darryl , Yellen Ben , Friedman Gary , Levy Robert J.
Published: January 2008

A cell delivery strategy was investigated that was hypothesized to enable magnetic targeting of endothelial cells to the steel surfaces of intraarterial stents because of the following mechanisms: (
i
) preloading cells with biodegradable polymeric superparamagnetic nanoparticles (MNPs), thereby rendering the cells magnetically responsive; and (
ii
) the induction of both magnetic field gradients around the wires of a steel stent and magnetic moments within MNPs because of a uniform external magnetic field, thereby targeting MNP-laden cells to the stent wires.
In vitro
studies demonstrated that MNP-loaded bovine aortic endothelial cells (BAECs) could be magnetically targeted to steel stent wires.
In vivo
MNP-loaded BAECs transduced with adenoviruses expressing luciferase (Luc) were targeted to stents deployed in rat carotid arteries in the presence of a uniform magnetic field with significantly greater Luc expression, detected by
in vivo
optical imaging, than nonmagnetic controls.
Assembly of Weibel–Palade body-like tubules from N-terminal domains of von Willebrand factor
Authors: Huang Ren-Huai , Wang Ying , Roth Robyn , Yu Xiong , Purvis Angie R. , Heuser John E. , Egelman Edward H. , Sadler J. Evan
Published: January 2008

Endothelial cells assemble von Willebrand factor (VWF) multimers into ordered tubules within storage organelles called Weibel–Palade bodies, and tubular packing is necessary for the secretion of VWF filaments that can bind connective tissue and recruit platelets to sites of vascular injury. We now have recreated VWF tubule assembly
in vitro
, starting with only pure VWF propeptide (domains D1D2) and disulfide-linked dimers of adjacent N-terminal D′D3 domains. Assembly requires low pH and calcium ions and is reversed at neutral pH. Quick-freeze deep-etch electron microscopy and three-dimensional reconstruction of negatively stained images show that tubules contain a repeating unit of one D′D3 dimer and two propeptides arranged in a right-handed helix with 4.2 units per turn. The symmetry and location of interdomain contacts suggest that decreasing pH along the secretory pathway coordinates the disulfide-linked assembly of VWF multimers with their tubular packaging.
Evolution of GITRL immune function: Murine GITRL exhibits unique structural and biochemical properties within the TNF superfamily
Authors: Chattopadhyay Kausik , Ramagopal Udupi A. , Brenowitz Michael , Nathenson Stanley G. , Almo Steven C.
Published: January 2008

Glucocorticoid-induced TNF receptor ligand (GITRL), a recently identified member of the TNF superfamily, binds to its receptor, GITR, on both effector and regulatory T cells and generates positive costimulatory signals implicated in a wide range of T cell functions. In contrast to all previously characterized homotrimeric TNF family members, the mouse GITRL crystal structure reveals a previously unrecognized dimeric assembly that is stabilized via a unique “domain-swapping” interaction. Consistent with its crystal structure, mouse GITRL exists as a stable dimer in solution. Structure-guided mutagenesis studies confirmed the determinants responsible for dimerization and support a previously unrecognized receptor-recognition surface for mouse GITRL that has not been observed for any other TNF family members. Taken together, the unique structural and biochemical behavior of mouse GITRL, along with the unusual domain organization of murine GITR, support a previously unrecognized mechanism for signaling within the TNF superfamily.
Hybrid huberized support vector machines for microarray classification and gene selection
Authors: Wang Li , Zhu Ji , Zou Hui
Published: January 2008

Motivation: The standard L2-norm support vector machine (SVM) is a widely used tool for microarray classification. Previous studies have demonstrated its superior performance in terms of classification accuracy. However, a major limitation of the SVM is that it cannot automatically select relevant genes for the classification. The L1-norm SVM is a variant of the standard L2-norm SVM, that constrains the L1-norm of the fitted coefficients. Due to the singularity of the L1-norm, the L1-norm SVM has the property of automatically selecting relevant genes. On the other hand, the L1-norm SVM has two drawbacks: (1) the number of selected genes is upper bounded by the size of the training data; (2) when there are several highly correlated genes, the L1-norm SVM tends to pick only a few of them, and remove the rest.

Results: We propose a hybrid huberized support vector machine (HHSVM). The HHSVM combines the huberized hinge loss function and the elastic-net penalty. By doing so, the HHSVM performs automatic gene selection in a way similar to the L1-norm SVM. In addition, the HHSVM encourages highly correlated genes to be selected (or removed) together. We also develop an efficient algorithm to compute the entire solution path of the HHSVM. Numerical results indicate that the HHSVM tends to provide better variable selection results than the L1-norm SVM, especially when variables are highly correlated.

Availability: R code are available at http://www.stat.lsa.umich.edu/~jizhu/code/hhsvm/

Contact: jizhu@umich.edu

Supplementary information: Supplementary data are available at Bioinformatics online.
Structural systems identification of genetic regulatory networks
Authors: Xiong Hao , Choe Yoonsuck
Published: January 2008

Motivation: Reverse engineering of genetic regulatory networks from experimental data is the first step toward the modeling of genetic networks. Linear state-space models, also known as linear dynamical models, have been applied to model genetic networks from gene expression time series data, but existing works have not taken into account available structural information. Without structural constraints, estimated models may contradict biological knowledge and estimation methods may over-fit.

Results: In this report, we extended expectation-maximization (EM) algorithms to incorporate prior network structure and to estimate genetic regulatory networks that can track and predict gene expression profiles. We applied our method to synthetic data and to SOS data and showed that our method significantly outperforms the regular EM without structural constraints.

Availability: The Matlab code is available upon request and the SOS data can be downloaded from http://www.weizmann.ac.il/mcb/UriAlon/Papers/SOSData/, courtesy of Uri Alon. Zak's data is available from his website, http://www.che.udel.edu/systems/people/zak

Contact:  hxiong@cs.tamu.edu

Supplementary information: Supplementary data are available at Bioinformatics online.
Structural search and retrieval using a tableau representation of protein folding patterns
Authors: Konagurthu Arun S. , Stuckey Peter J. , Lesk Arthur M.
Published: January 2008

Comparison and classification of folding patterns from a database of protein structures is crucial to understand the principles of protein architecture, evolution and function. Current search methods for proteins with similar folding patterns are slow and computationally intensive. The sharp growth in the number of known protein structures poses severe challenges for methods of structural comparison. There is a need for methods that can search the database of structures accurately and rapidly.

We provide several methods to search for similar folding patterns using a concise tableau representation of proteins that encodes the relative geometry of secondary structural elements. Our first approach allows the extraction of identical and very closely-related protein folding patterns in constant-time (per hit). Next, we address the hard computational problem of extraction of maximally-similar subtableaux, when comparing two tableaux. We solve the problem using Quadratic and Linear integer programming formulations and demonstrate their power to identify subtle structural similarities, especially when protein structures significantly diverge. Finally, we describe a rapid and accurate method for comparing a query structure against a database of protein domains, TableauSearch. TableauSearch is rapid enough to search the entire structural database in seconds on a standard desktop computer. Our analysis of TableauSearch on many queries shows that the method is very accurate in identifying similarities of folding patterns, even between distantly related proteins.

Availability: A web server implementing the TableauSearch is available from http://hollywood.bx.psu.edu/TabSearch

Contact:  arun@bx.psu.edu, aml25@psu.edu

Supplementary information: Supplementary Data are available at Bioinformatics online.
Identification of Genes Relevant to Symbiosis and Competitiveness in Sinorhizobium meliloti Using Signature-Tagged Mutants
Authors: Pobigaylo Nataliya , Szymczak Silke , Nattkemper Tim W. , Becker Anke
Published: January 2008

Sinorhizobium meliloti enters an endosymbiosis with alfalfa plants through the formation of nitrogen-fixing nodules. In order to identify S. meliloti genes required for symbiosis and competitiveness, a method of signature-tagged mutagenesis was used. Two sets, each consisting of 378 signature-tagged mutants with a known transposon insertion site, were used in an experiment in planta. As a result, 67 mutants showing attenuated symbiotic phenotypes were identified, including most of the exo, fix, and nif mutants in the sets. For 38 mutants in genes previously not described to be involved in competitiveness or symbiosis in S. meliloti, attenuated competitiveness phenotypes were tested individually. A large part of these phenotypes was confirmed. Moreover, additional symbiotic defects were observed for mutants in several novel genes such as infection deficiency phenotypes (ilvI and ilvD2 mutants) or delayed nodulation (pyrE, metA, thiC, thiO, and thiD mutants).
Characterization of Phytophthora capsici Causing Foliar and Pod Blight of Snap Bean in Michigan
Authors: Gevens A. J. , Donahoo R. S. , Lamour K. H. , Hausbeck M. K.
Published: January 2008

Green and yellow snap bean plants with water-soaked foliar lesions, stem necrosis, pod blight, and overall plant decline were observed in four commercial fields in three Michigan counties during 2003 to 2005. All fields were cropped to cucurbits that exhibited symptoms of Phytophthora capsici infection in recent years. In all, 680 isolates of P. capsici were obtained from bean stems, petioles, leaves, and pods; the pathogen was not recovered from roots. Koch's postulates were completed with representative isolates, confirming P. capsici as the causal organism. Select isolates also were pathogenic on cucumber fruit, causing symptoms consistent with P. capsici infection. The majority of the P. capsici isolates collected were sensitive to the fungicide mefenoxam and were of the A1 mating type. Under laboratory conditions, six P. capsici isolates from snap bean (2003) were pathogenic on 12 different commercial bean cultivars, including soybean. Infected bean plants exhibited water-soaked lesions, foliar necrosis, and wilting. We subjected 131 isolates collected from 2003 and 2004 to amplified fragment length polymorphism analysis to investigate diversity among isolates and geographical populations and to determine whether bean P. capsici isolates were similar to isolates from a cucurbit host. This is the first in-depth study of P. capsici on snap bean in Michigan. Although bean cultivars previously were considered a suitable rotation for crops susceptible to P. capsici, this is no longer a recommended practice.
Host–Pathogen Interactions Among Barley Genotypes and Bipolaris sorokiniana Isolates
Authors: Ghazvini H. , Tekauz A.
Published: January 2008

Spot blotch, caused by Bipolaris sorokiniana, is a damaging foliar disease of barley (Hordeum vulgare) and other cereal grains in Canada. In order to deploy resistance as an effective management tool, information on the virulence diversity present in the local population of the pathogen is necessary. Speculation regarding the presence of differential virulence versus continuous aggressiveness in B. sorokiniana isolates was begun when isolates with differential virulence on the barley cv. Bowman and its derivatives were reported in North Dakota. To further evaluate the H. vulgare–B. sorokiniana interaction model, the infection responses induced by 127 isolates of the pathogen collected from Canada and other parts of the world were analyzed on 12 differential barley lines using quantitative approaches. Analysis of the data based on infection response elicited on the barley differentials resulted in an enhanced understanding of the host–pathogen interactions and in the relationships among isolates, compared with the classical method of pathotype identification. The population of B. sorokiniana was determined to consist of three distinct pathogenic groups (having low virulence, differential virulence, and virulence with varying levels of aggressiveness). The results of the various quantitative approaches indicated that complex interactions exist among barley genotypes and B. sorokiniana isolates of the third pathogenic group which cannot be analyzed easily using the classical method of pathotype identification. It also was inferred that the gene-for-gene model is not the principal system operating in the H. vulgare–B. sorokiniana pathosystem, although this plays a role in some interactions.
Detection and Characterization of Benzimidazole Resistance in California Populations of Colletotrichum cereale
Authors: Wong Francis P. , de la Cerda Karla A. , Hernandez-Martinez Rufina , Midland Sharon L.
Published: January 2008

Colletotrichum cereale is the causal agent of turfgrass anthracnose, which has become a serious problem on annual bluegrass (Poa annua) and creeping bentgrass (Agrostis palustris) golf course putting greens. Thiophanate-methyl is a benzimidazole (methyl benzimidazole carbamate [MBC]) fungicide used for the management of anthracnose. In this study, we examined 481 isolates from 10 California populations to determine the presence and frequency of MBC resistance. An in vitro methodology was developed to construct a baseline sensitivity distribution using 60 isolates from an unexposed population (TCGC). The 50% effective dose (ED50) values for the baseline sensitivity distribution for thiophanate-methyl ranged from 0.14 to 2.3 μg/ml with a mean of 0.75 μg/ml. For 60 isolates assayed from an exposed population (AHCC), 57 isolates were not responsive to in vitro concentrations of thiophanate-methyl of up to 30 μg/ml. Isolates nonresponsive to thiophanate-methyl were not responsive to benomyl in vitro. Two isolates nonresponsive in vitro to thiophanate-methyl or benomyl were not controlled in vivo on annual bluegrass plants treated preventively with either fungicide at 11 mg/ml, confirming the results of the in vitro testing. The remaining 361 isolates from eight populations were tested using the single discriminatory dose of thiophanate-methyl at 10 μg/ml. A high proportion (>90%) of isolates from six of the populations were resistant to thiophanate-methyl, indicating the presence of practical resistance at these locations. To determine the molecular mechanism of MBC resistance, the two β-tubulin genes, TUB1 and TUB2, of 12 resistant and 6 sensitive isolates were amplified and sequenced, revealing a glutamic acid to lysine substitution at position 198 of TUB2 that was present in all resistant isolates. This work confirms the presence of MBC resistance in C. cereale populations from California and presents methods and information that can be used to manage resistance to the MBC fungicides and improve anthracnose management programs.
Effect of Incorporation of Brassica spp. Residues on Population Densities of Soilborne Microorganisms and on Damping-off and Fusarium Wilt of Watermelon
Authors: Njoroge Samuel M. C. , Riley Melissa B. , Keinath Anthony P.
Published: January 2008

Incorporating Brassica spp. residue to reduce populations of soilborne fungi and manage damping-off and Fusarium wilt of watermelon (Citrullus lanatus var. lanatus) was studied in two field experiments. Treatments included incorporating flowering Brassica napus cv. Dwarf Essex canola or B. juncea cv. Cutlass mustard and laying black polyethylene mulch at incorporation or 1 month after incorporation, methyl bromide, and a nontreated control. In both years, glucosinolates were identified and quantified in the shoots and roots of the flowering plants. In both years, the total concentration of glucosinolates incorporated per square meter was significantly higher for B. juncea than for B. napus. Isothiocyanates were inconsistently detected in the amended soils and none were detected more than 12 days postincorporation. After incorporation in 2004 and 2005, amended plots had higher populations of Fusarium oxysporum and Pythium spp. than the methyl bromide treatment, and in some treatments, populations were higher than in the control. Fluorescent Pseudomonas spp. were not suppressed in amended soils, and their populations were significantly higher in some amended treatments than those in methyl bromide-treated soils or nontreated control soils. Incidence of damping-off and severity of Fusarium wilt on seedless watermelon cv. Tri-X 313, which is susceptible to Fusarium wilt, were not consistently lower in brassica-amended soils or methyl bromide-treated plots than in nontreated control plots. Therefore, under spring conditions and methods used in this study, neither biofumigation nor methyl bromide fumigation in coastal South Carolina was an effective disease management tool for two soilborne pathogens of watermelon.
First Detection of Virulence to Genes Lr9 and Lr25 Conferring Resistance to Leaf Rust of Wheat Caused by Puccinia triticina in Mexico
Authors: Huerta-Espino J. , Singh R. P. , Reyna-Martinez J.
Published: January 2008

Leaf rust resistance gene Lr9 was transferred to wheat from Triticum umbellulatum (1). In 1971, 4 years after cultivars with this gene were released in the United States, leaf rust races with virulence to Lr9 were detected. In Mexico, cultivars with Lr9 have not been released and leaf rust races with Lr9 virulence have not been detected. Resistance gene Lr25 was transferred to wheat from Rosen rye (1) and has been effective worldwide, but this gene has not been used commercially because of possible negative effects on yield (1). Rust samples collected at different locations in Nuevo Leon State of Mexico during the 2004–2005 and 2005–2006 wheat crop seasons were analyzed on seedlings of wheat leaf rust differentials in the greenhouse from single pustule isolates. The race nomenclature used is described in Singh (2). Among the races identified from this area, seven, MLJ/SP, TNM/JP, TLB/JP, TNM/KP, TNR/JP, TNB/JN, and TMB/JP, were virulent to both of these genes. Virulence to Lr9 and Lr25 were confirmed by repeating tests using Lr9 differentials ‘RL6010’ and ‘McNair 701’ and Transec and three other Lr25 wheat lines developed at CIMMYT, which carry Lr25. To our knowledge, this is the first confirmed report of virulence to Lr9 in Mexico and virulence to Lr25 in the world. These isolates are conserved at CIMMYT for future reference.

References: (1) R. A. McIntosh et al. Wheat Rusts: An Atlas of Resistance Genes. CSIRO Publishing, Melbourne, Australia, 1995. (2) R. P. Singh. Plant Dis. 75:790, 1991.
First Report of ‘Candidatus Liberibacter asiaticus’ from Atalantia buxifolia in Guangdong, China
Authors: Deng X. , Lou Z. , Feng Z. , Li H. , Chen J. , Civerolo E. L.
Published: January 2008

Atalantia buxifolia (Poir.) Oliv., synonym Severinia buxifolia (Poir.) Ten. as commonly found in literature, is a common landscape plant and a popular Chinese medicinal herb known as Jiubingle or Dongfengjie. It remains unclear if this rutaceous plant could host ‘Candidatus Liberibacter asiaticus’, the pathogen of citrus Huanglongbing (HLB) in Guangdong, P. R. China. This information is important for HLB control in citrus because infected A. buxifolia could serve as a source of inoculum. In August of 1994, three A. buxifolia plants adjacent to a citrus experimental orchard of the South China Agricultural University at Guangzhou were found showing leaf mottle/yellowing symptoms. Two buds from each plant were grafted onto three mandarin trees (Citrus reticulata cv. Pongan) in a psyllid-proof screenhouse for indexing. By October of 1995, typical leaf mottle symptoms were observed in all three grafted trees compared with a healthy control. In March of 1996, one of the A. buxifolia plants was transferred to a screenhouse and has been maintained there. The leaf mottle/yellowing symptoms persisted but did not significantly affect plant growth. DNA was extracted from leaf samples in October 2006 by using the CTAB (cetyltrimethylammoniumbromide) method and assayed by nested-PCR using the general bacterial 16S rDNA primer set fDl/rD1 as the first round of amplification and primer set OI1/OI2c as second round amplification (1,3). After agarose gel electrophoresis and staining with ethidium bromide, an approximate 1.1-kb DNA band was detected in symptomatic samples but not healthy leaf samples of A. buxifolia and C. reticulata. XbaI digestion of the amplicons yielded approximate 500- and 600-bp fragments, characteristic of ‘Ca. L. asiaticus’. Similarly, a standard PCR with primer set A5/J2 (3) yielded an approximate 700-bp DNA band characteristic of ‘Ca. L. asiaticus’ from symptomatic samples only. To our knowledge, this is the first report of graft transmission and PCR detection of ‘Ca. L. asiaticus’ from A. buxifolia in Guangdong, P. R. China. This work also confirms the findings from Taiwan (2) that A. buxifolia could serve as a source of ‘Ca. L. asiaticus’.

References: (1) X. Deng et al. Online publication. doi:10.1094/PHP-2007-0419-01-BR. Plant Health Progress, 2007. (2) T.-H. Hung et al. Eur. J. Plant Pathol. 107:183, 2001. (3) S. Jagoueix et al. Mol. Cell. Probes 10:43, 1996.
Severe and Widespread Clubroot Epidemics in Nepal
Authors: Timila R. D. , Correll J. C. , Duwadi V. R.
Published: January 2008

Cultivation of brassica vegetables has the highest potential for generating income among more traditional rice and maize farmers in Nepal. Among brassica vegetables, the most important are cauliflower (Brassica oleracea var. botrytis L.) and cabbage (B. oleracea var. capitata L.). Although clubroot disease, caused by Plasmodiophora brassicae Woronin, has been observed in Nepal since 1993, severe and widespread epidemics have been observed since 2004 in the Bhaktapur, Kathmandu, Lalitpur, and Palung Valley production areas. Typical disease symptoms (1) are widespread, and disease severity has been particularly severe in the Kathmandu Valley and Palung/Daman area of the Makwanpur District. Many cauliflower fields in these areas have had as much as 100% yield loss between 2004 and 2006 with an estimated 40% overall loss from clubroot. Estimates from interviews with growers in the Palung production area during an intensive farmers' interaction program indicated that cauliflower production was reduced from 5 to 6 metric tons per household (1,500 m2) prior to 2004 to <300 kg per household in 2004 and beyond. The economic loss in this area alone was estimated at $1.4 million in 2004 and 2005. Examination of transplant nurseries indicated that frequently >80% of the seedlings have symptoms of clubroot at the time of transplanting. Soil samples from throughout the production areas indicated that the sandy loam soils were predominately acidic (pH range of 4.2 to 7.2 with >90% below 6.0). Several management practices are being employed to reduce disease severity, including the use of clubroot resistant cultivars, raising the soil pH to >7.0 by using dolomitic lime, testing of the fungicide flusulfamide (Nebijin) and biopesticide Sanjeevani (Trichoderma viride), and biofumigation and solarization of the nursery beds in an effort to reduce disease pressure on transplant material.

References: (1) G. R. Dixon. Compendium of Brassica Diseases. S. R. Rimmer et al., eds. American Phytopathological Society, St. Paul, 2007.
First Report of a Leaf Spot on Snow Lotus Caused by Alternaria carthami in China
Authors: Zhao S. , Xie G. , Zhao H. , Li H. , Li C.
Published: January 2008

Snow lotus (Saussurea involucrata Karel. & Kir. ex Sch. Bip.) is an economically important medicinal herb increasingly grown in China in recent years. In June of 2005, a leaf spot disease on commercially grown plants was found in the QiTai Region, south of the Tianshan Mountain area of Xinjiang, China at 2,100 m above sea level. Disease incidence was approximately 60 to 70% of the plants during the 2006 and 2007 growing seasons. Initial symptoms appeared on older leaves as irregularly shaped, minute, dark brown-to-black spots, with yellow borders on the edge of the leaflet blade by July. As the disease progressed, the lesions expanded, causing the leaflets to turn brown, shrivel, and die. A fungus was consistently isolated from the margins of these lesions on potato dextrose agar. Fifty-eight isolates were obtained that produced abundant conidia in the dark. Conidia were usually solitary, rarely in chains of two, ellipsoid to obclavate, with 6 to 11 transverse and one longitudinal or oblique septum. Conidia measured 60 to 80 × 20 to 30 μm, including a filamentous beak (13 to 47 × 3.5 to 6 μm). According to the morphology, and when compared with the standard reference strains, the causal organism of leaf spot of snow lotus was identified as Alternaria carthami (1,4). Pathogenicity of the strains was tested on snow lotus seedlings at the six-leaf stage. The lower leaves of 20 plants were sprayed until runoff with conidial suspensions of 1 × 104 spores mL–1, and five plants sprayed with sterile distilled water served as controls. All plants were covered with a polyethylene bag, incubated at 25°C for 2 days, and subsequently transferred to a growth chamber at 25°C with a 16-h photoperiod. Light brown lesions developed within 10 days on leaflet margins in all inoculated plants. The pathogen was reisolated from inoculated leaves, and isolates were deposited at the Key Oasis Eco-agriculture Laboratory of Xinjiang Production and Construction Group, Xinjiang and the Institute of Biotechnology, Zhejiang University. No reports of a spot disease caused by A. carthami on snow lotus leaves have been found, although this pathogen has been reported on safflower in western Canada (3), Australia (2), India (1), and China (4). To our knowledge, this is the first report of a leaf spot caused by A. carthami on snow lotus in China.

References: (1) S. Chowdhury. J. Indian Bot. Soc. 23:59, 1944. (2) J. A. G. Irwin. Aust. J. Exp. Agric. Anim. Husb. 16:921, 1976. (3) G. A. Petrie. Can. Plant Dis. Surv. 54:155, 1974. (4) T. Y. Zhang. J. Yunnan Agric. Univ.17:320, 2002.
Further twists in gastropod shell evolution
Authors: Clements Reuben , Liew Thor-Seng , Vermeulen Jaap Jan , Schilthuizen Menno
Published: January 2008

The manner in which a gastropod shell coils has long intrigued laypersons and scientists alike. In evolutionary biology, gastropod shells are among the best-studied palaeontological and neontological objects. A gastropod shell generally exhibits logarithmic spiral growth, right-handedness and coils tightly around a single axis. Atypical shell-coiling patterns (e.g. sinistroid growth, uncoiled whorls and multiple coiling axes), however, continue to be uncovered in nature. Here, we report another coiling strategy that is not only puzzling from an evolutionary perspective, but also hitherto unknown among shelled gastropods. The terrestrial gastropodOpisthostoma vermiculumsp. nov. generates a shell with: (i) four discernable coiling axes, (ii) body whorls that thrice detach and twice reattach to preceding whorls without any reference support, and (iii) detached whorls that coil around three secondary axes in addition to their primary teleoconch axis. As the coiling strategies of individuals were found to be generally consistent throughout, this species appears to possess an unorthodox but rigorously defined set of developmental instructions. Although the evolutionary origins ofO. vermiculumand its shell's functional significance can be elucidated only once fossil intermediates and live individuals are found, its bewildering morphology suggests that we still lack an understanding of relationships between form and function in certain taxonomic groups.
New results concerning power series expansions of the Riemann xi function and the Li/Keiper constants
Authors: Coffey Mark W
Published: January 2008

The Riemann hypothesis is equivalent to the Li criterion governing a sequence of real constants

that are certain logarithmic derivatives of the Riemann xi function evaluated at unity. A new representation of
λ

k

is developed in terms of the Stieltjes constants
γ

j

and the subcomponent sums are discussed and analysed. Accompanying this decomposition, we find a new representation of the constants
η

j

entering the Laurent expansion of the logarithmic derivative of the Riemann zeta function about
s
=1. We also demonstrate that the
η

j

coefficients are expressible in terms of the Bernoulli numbers and certain other constants. We determine new properties of
η

j

and
σ

j

, where

are the sums of reciprocal powers of the non-trivial zeros of the Riemann zeta function.
Shear compliance of two-dimensional pores possessing
N
-fold axis of rotational symmetry
Authors: Ekneligoda Thushan C , Zimmerman Robert W
Published: January 2008

We use the complex variable method and conformal mapping to derive a closed-form expression for the shear compliance parameters of some two-dimensional pores in an elastic material. The pores have an
N
-fold axis of rotational symmetry and can be represented by at most three terms in the mapping function that conformally maps the exterior of the pore into the interior of the unit circle. We validate our results against the solutions of some special cases available in the literature, and against boundary-element calculations. By extrapolation of the results for pores obtained from two and three terms of the Schwarz–Christoffel mapping function for regular polygons, we find the shear compliance of a triangle, square, pentagon and hexagon. We explicitly verify the fact that the shear compliance of a symmetric pore is independent of the orientation of the pore relative to the applied shear, for all cases except pores of fourfold symmetry. We also show that pores having fourfold symmetry, or no symmetry, will have shear compliances that vary with cos 4
θ
. An approximate scaling law for the shear compliance parameter, in terms of the ratio of perimeter squared to area, is proposed and tested.
Synaesthetic colours do not camouflage form in visual search
Authors: Gheri C , Chopping S , Morgan M.J
Published: January 2008

One of the major issues in synaesthesia research is to identify the level of processing involved in the formation of the subjective colours experienced by synaesthetes: are they perceptual phenomena or are they due to memory and association learning? To address this question, we tested whether the colours reported by a group of grapheme-colour synaesthetes (previously studied in an functional magnetic resonance imaging experiment) influenced them in a visual search task. As well as using a condition where synaesthetic colours should have aided visual search, we introduced a condition where the colours experienced by synaesthetes would be expected to make them worse than controls. We found no evidence for differences between synaesthetes and normal controls, either when colours should have helped them or where they should have hindered. We conclude that the colours reported by our population of synaesthetes are not equivalent to perceptual signals, but arise at a cognitive level where they are unable to affect visual search.
A clear human footprint in the coral reefs of the Caribbean
Authors: Mora Camilo
Published: January 2008

The recent degradation of coral reefs worldwide is increasingly well documented, yet the underlying causes remain debated. In this study, we used a large-scale database on the status of coral reef communities in the Caribbean and analysed it in combination with a comprehensive set of socioeconomic and environmental databases to decouple confounding factors and identify the drivers of change in coral reef communities. Our results indicated that human activities related to agricultural land use, coastal development, overfishing and climate change had created independent and overwhelming responses in fishes, corals and macroalgae. While the effective implementation of marine protected areas (MPAs) increased the biomass of fish populations, coral reef builders and macroalgae followed patterns of change independent of MPAs. However, we also found significant ecological links among all these groups of organisms suggesting that the long-term stability of coral reefs as a whole requires a holistic and regional approach to the control of human-related stressors in addition to the improvement and establishment of new MPAs.
Observational learning in chimpanzees and children studied through ‘ghost’ conditions
Authors: Hopper Lydia M , Lambeth Susan P , Schapiro Steven J , Whiten Andrew
Published: January 2008

Emulation has been distinguished from imitation as a form of observational learning because it focuses not on the model's actions but on the action's environmental results. Whether a species emulates, imitates or displays only simpler observational learning is expected to have profound implications for its capacity for cultural transmission. Chimpanzees' observational learning has been suggested to be primarily emulative, but this is an inference largely based upon low fidelity copying in experiments when comparing chimpanzees with humans rather than direct testing. Here we test directly for emulation learning by chimpanzees and children using a ‘ghost’ condition in which a sliding door obscuring a reward was moved to left or right with no agent visible, a context associated with the only published evidence for emulation learning in a non-human species (pigeons). Both children and chimpanzees matched the observed direction of ghost door movement on their first test trial. This is the first evidence for emulation in a non-human primate in the restricted context of a ghost condition. However, only the children continued to match in later trials. Individuals of both species continued to match with 99% or better fidelity when viewing a conspecific model operates the door. We conclude that chimpanzees can and will display emulation learning when the task is as simple as the present one, which contrasts with a failure to do so in a more complex manipulative task tested earlier. However, even with a simple task, emulation alone creates only fleeting fidelity compared with the opportunity to copy a conspecific, when considerable conformity is displayed.
SEUSSandAINTEGUMENTAMediate Patterning and Ovule Initiation during Gynoecium Medial Domain Development
Authors: Azhakanandam Sridevi , Nole-Wilson Staci , Bao Fang , Franks Robert G.
Published: January 2008

The Arabidopsis (Arabidopsis thaliana) gynoecium, the female floral reproductive structure, requires the action of genes that specify positional identities during its development to generate an organ competent for seed development and dispersal. Early in gynoecial development, patterning events divide the primordium into distinct domains that will give rise to specific tissues and organs. The medial domain of the gynoecium gives rise to the ovules, and several other structures critical for reproductive competence. Here we report a synergistic genetic interaction between seuss and aintegumenta mutants resulting in a complete loss of ovule initiation and a reduction of the structures derived from the medial domain. We show that patterning events are disrupted early in the development of the seuss aintegumenta gynoecia and we identify PHABULOSA (PHB), REVOLUTA, and CRABS CLAW (CRC) as potential downstream targets of SEUSS (SEU) and AINTEGUMENTA (ANT) regulation. Our genetic data suggest that SEU additionally functions in pathways that are partially redundant and parallel to PHB, CRC, and ANT. Thus, SEU and ANT are part of a complex and robust molecular system that coordinates patterning cues and cellular proliferation along the three positional axes of the developing gynoecium.
Identification of the structure and origin of a thioacidolysis marker compound for ferulic acid incorporation into angiosperm lignins (and an indicator for cinnamoyl CoA reductase deficiency)
Authors: Ralph John , Kim Hoon , Lu Fachuang , Grabber John H. , Leplé Jean‐Charles , Berrio‐Sierra Jimmy , Derikvand Mohammad Mir , Jouanin Lise , Boerjan Wout , Lapierre Catherine
Published: January 2008

A molecular marker compound, derived from lignin by the thioacidolysis degradative method, for structures produced when ferulic acid is incorporated into lignin in angiosperms (poplar, Arabidopsis, tobacco), has been structurally identified as 1,2,2‐trithioethyl ethylguaiacol [1‐(4‐hydroxy‐3‐methoxyphenyl)‐1,2,2‐tris(ethylthio)ethane]. Its truncated side chain and distinctive oxidation state suggest that it derives from ferulic acid that has undergone bis‐8‐O‐4 (cross) coupling during lignification, as validated by model studies. A diagnostic contour for such structures is found in two‐dimensional 13C–1H correlated (HSQC) NMR spectra of lignins isolated from cinnamoyl CoA reductase (CCR)‐deficient poplar. As low levels of the marker are also released from normal (i.e. non‐transgenic) plants in which ferulic acid may be present during lignification, notably in grasses, the marker is only an indicator for CCR deficiency in general, but is a reliable marker in woody angiosperms such as poplar. Its derivation, together with evidence for 4‐O‐etherified ferulic acid, strongly implies that ferulic acid is incorporated into angiosperm lignins. Its endwise radical coupling reactions suggest that ferulic acid should be considered an authentic lignin precursor. Moreover, ferulic acid incorporation provides a new mechanism for producing branch points in the polymer. The findings sharply contradict those reported in a recent study on CCR‐deficient Arabidopsis.
THE ONTARIO HOSPITAL SERVICES PLAN: A NOTE ON PROGRAM DESIGN AND EVALUATION*
Authors: Taylor Malcolm
Published: January 2008

The Ontario Hospital Services Plan, as a part of the national hospital insurance program, does not go into operation until January 1, 1959. Nevertheless, it may be worth while to examine now the essential elements in its design and to indicate some of the criteria by which it may be evaluated in the future.
Management education for tomorrow's society†
Authors: Debanné J. G.
Published: January 2008

Abstract. This paper attempts to anticipate the evolution of several key aspects of the modern life as these will shape the environment in which tomorrow's managers will have to manage. Some attributes of this milieu, in particular, would affect the talent and skill profile of tomorrow's manager, and these are: (i) society and the environment, (ii) information systems, (iii) man, (iv) organizations.

A threefold methodology will be used in this ‘futures’ exercise, consisting of (a) extrapolation ‐ mostly implicit, coupled with (b) limit information, and (c) analogy with other evolutionary phenomena. These three techniques will be described within the context of their application.

The managerial attributes considered desirable and perhaps essential in the future will be discussed when dealing with the evolution of society, information systems, man and organizations. Conversely, those special attributes, considered important in bygone days or even today but which are expected to be non‐essential in the future, will be touched upon briefly.

Sommaire. Cette communication essaie d'anticiper l'évolution de différents aspects de la vie moderne dans la mesure où ils façonnent le milieu que les cadres de l'avenir devront gérer. Certains éléments de ce milieu détermineront les talents et la compétence des cadres de l'avenir, et ce sont (i) la société et le milieu, (ii) les systèmes d'information, (iii) l'homme, (iv) les organisations.

Nous utiliserons une médiodologie tripartite pour les exercices de projection qui consistera (a) en une interpolation ‐ surtout implicite ‐ combinée avec une information limite et (c) l'analogie avec d'autres phénomènes d'évolution. Nous décrirons ces trois techniques dans le contexte de leur application.

Nous parlerons des qualités considérées comme désirables et peut‐être essentielles chez les cadres de l'avenir lorsque nou traiterons de l'évolution de la société, des systèmes d'information, de l'homme et des organisations. Par contre, nous ne mentionnerons que brievement les qualités particulières qui étaient considérées comme importantes autrefois ou même aujourd'hui mais qui ne semblent pas essentielles pour l'avenir.