bluuebunny/crossref_metadata_2025 huggingface dataset:
Antagonism of white mold (Sclerotinia sclerotiorum) of bean by fungi from bean and rapeseed flowers
Authors: Boland G. J. , Inglis G. D.
Published: September 2008

Filamentous fungi from white bean and rapeseed flowers were isolated, characterized, and evaluated for potential as antagonists to Sclerotinia sclerotiorum (Lib.) de Bary. Various fungi were isolated from surface-sterilized petals sampled from four developmental stages ranging from freshly opened flowers to petals that had lodged on plant surfaces. Alternaria and Cladosporium spp. were the dominant mycoflora and were isolated from 65–100% of the petals that developed fungal colonies. All isolates, except one, restricted ascospore germination by the pathogen on water agar by 16–66%, and 13 of 28 isolates restricted mycelial growth on potato dextrose agar by 29–46%. Bean flowers were inoculated with spore suspensions of S. sclerotiorum and of individual antagonists and were then placed on detached bean leaves, bean seedlings, and flowering bean plants. On detached leaves in a laboratory environment, 16 of 28 isolates suppressed white mold lesion diameter by 10–100%. On bean seedlings in a growth room, 8 isolates suppressed the percentage of flowers developing lesions by 42–100%, and 12 of 13 isolates reduced mean lesion diameter by 14–100%. On flowering bean plants in a greenhouse, 6 of 11 isolates suppressed the percentage of flowers developing lesions by 14–90 %. The most disease-suppressive fungi included isolates of Drechslera sp., Epicoccum purpurascens, Fusarium graminearum, and Fusarium heterosporum; isolates of Myrothecium verrucaria and Trichoderma viride were effective in some trials.
Variation in culm anatomy among barley cultivars differing in lodging resistance
Authors: Dunn G. J. , Briggs K. G.
Published: September 2008

Five registered Canadian six-row barley (Hordeum vulgare L.) cultivars, including two recently registered semidwarfs ('Duke' and 'Samson'), that differ in lodging resistance and height were studied over 2 years for differences in morphological and anatomical characteristics of culms that could be related to lodging resistance. Plants were grown in nonirrigated field plots at a population density of 220 plants/m2 under conditions of high soil fertility. Significant cultivar differences were observed for culm length, number of internodes, length of four basal internodes, culm diameter, culm wall thickness, number of vascular bundles, and thickness of the sclerenchyma ring. No cultivar differences were found for thickness of the sclerenchyma cell walls. Of the characters studied, culm length, basal internode length, culm wall thickness, and sclerenchyma ring thickness were most closely associated with differences in lodging resistance among the cultivars. The results of this study indicate that it may be possible to select lodging resistant genotypes from early generations in breeding programs on the basis of these traits.
The flagellar apparatus in zoospores of Phytophthora sojae f.sp. glycines and P. megasperma
Authors: Barr D. J. S. , Désaulniers N. L.
Published: September 2008

The zoospores of Phytophthora sojae Kaufmann and Gerdemann and P. megasperma Drechsler are cytologically similar. Their flagellar apparatus includes six rootlets consisting of an anterior ribbed triplet, a multistranded band-shaped rootlet with seven to eight microtubules, a posterior rootlet with four and three microtubules, respectively, an anterior doublet rootlet, and arrays of cytoplasmic and nuclear associated microtubules. The flagellar apparatus in these species is contrasted with the flagellar apparatus in P. cinnamomi Rands and P. parasitica Dastur, and with other Oomycetes. Key words: three-dimension image analysis, ultrastructure, fungi.
Pyxidiophora: life histories and arthropod associations of two species
Authors: Blackwell Meredith , Malloch David
Published: September 2008

Based on field studies in New Brunswick and Ontario, two species of the genus Pyxidiophora are demonstrated to be of frequent occurrence. Pyxidiophora sp. and Pyxidiophora spinuliformis have complex life cycles involving anamorph formation and sporulation on a phoretic mite host. Pyxidiophora sp., the more common of the two species, appears to be parasitic on the apothecia of coprophilous Pezizales where it forms clusters of synnemata within a week of dung deposition. Later, perithecia develop among the synnemata and produce ascospores. Ascospores attach to mites that are, in turn, carried by beetles and flies to a new substrate. On the new substrate while attached to the mite, ascospores of Pyxidiophora sp. differentiate into linearly arranged or complex and often muriform Thaxteriola thalli, which produce phialoconidia. The phialoconidia appear to be the propagules that inoculate the new substrate. Pyxidiophora spinuliformis has a life cycle similar to that of Pyxidiophora sp. but differs in having a conidial anamorph with a different development and ascospores that never form muriform thalli on the phoretic mite host. The taxonomic, ecological, and evolutionary significance of these findings is discussed.
Permineralized monocotyledons from the Middle Eocene Princeton chert (Allenby Formation) of British Columbia: Alismataceae
Authors: Erwin Diane M. , Stockey Ruth A.
Published: September 2008

One small monocotyledon petiole, 1.8 × 1.5 mm wide, has been recovered from the Princeton chert in the Middle Eocene Allenby Formation, British Columbia. The petiole, rectangular in transverse outline, shows approximately 36 circular to oval-shaped vascular bundles within aerenchymatous ground tissue that includes tannin cells. The epidermis is underlain by a discontinuous hypodermis of thick-walled, pitted cells. Vascular bundles are in five series: (I) a median U-shaped arc of 11 – 13 bundles; (II) an abaxial arc of 6 bundles located below the main arc; (III) two short abaxial arcs of 3 bundles each; (IV) 2 bundles just below the abaxial surface; and (V) an adaxial series of 7 bundles that show an inverse orientation to those bundles in series I–IV. Larger bundles are collateral, with a protoxylem lacuna encircled by a ring of 9 – 14 thin-walled parenchyma cells, a relatively well-developed phloem strand, and one to three thin-walled metaxylem elements. Based on bundle arrangement, orientation, and morphology, the fossil petiole most closely resembles those of the Butomaceae and Alismataceae. This new species, Heleophyton helobiaeoides Erwin and Stockey gen. et sp.nov., in the Princeton chert flora, documents the presence of the Alismataceae in the Middle Eocene of western North America and provides further evidence that the locality represents an ancient aquatic ecosystem.
Timing of a cellular reaction in rice cultivars associated with differing degrees of resistance to Pyricularia oryzae
Authors: Peng You-Liang , Shishiyama Jiko
Published: September 2008

To clarify the relationship between histological events and lesion formation in incompatible rice and rice blast fungus interaction, penetration frequency, growth of infection hyphae, and cellular reactions were compared in 12 cultivars, each of which showed one of the following four resistant reactions: highly resistant, resistant, moderately resistant, or intermediate. Penetration frequency varied depending on the cultivar, leaf age, and fungal isolate. Papilla-like structures were observed at some unsuccessful penetration sites, but their formation was too restricted to be responsible for the penetration failure of most conidia. Growth of infection hyphae stopped before 24 h in highly resistant cultivars, before 36 h in resistant cultivars, and later than 36 h in moderately resistant cultivars. The growth inhibition of infection hyphae was coincident with the occurrence of a light brown coloration and aniline blue staining of cell walls (B reactions) around infection sites in these cultivars. These results indicate a close relationship between occurrence of B reactions and growth inhibition of infection hyphae and suggest that the time required for B reactions to occur and for growth infection hyphae to stop varies according to degree of host resistance.
Ultrastructural characterization of an inner envelope that confines Azolla endosymbionts to the leaf cavity periphery
Authors: Nierzwicki-Bauer S. A. , Aulfinger H. , Braun-Howland E. B.
Published: September 2008

Ultrastructural characteristics of Azolla leaf cavities were examined using transmission electron microscopy. An extracellular inner envelope, which forms a boundary between the central cavity region and the peripheral region containing cyanobacteria and (or) bacteria, was found in all closed leaf cavities of symbiotic and Anabaena-free Azolla species. In the youngest leaf, which is in the process of developing a cavity, a continuous inner envelope was never observed. However, in young leaves that contained closed cavities, and in older leaves, continuous inner envelopes were always observed. The inner envelope may serve to restrict the symbionts to the cavity periphery. The inner envelope was similar in appearance to the outer envelope, which encloses the symbionts and hair cells within leaf cavities. Examination of the inner envelope using three different fixation procedures revealed that it was most distinct in fronds fixed in potassium permanganate, suggesting that it is membranelike in structure. The envelope was occasionally seen folded back upon itself or curled, which is also characteristic of a membranelike structure. Nevertheless, the envelope did not exhibit typical tripartite membrane ultrastructure. The occurrence of the inner envelope in Anabaena-free Azolla indicates that this envelope is of eubacterial or plant origin.
Variability among isolates of Diaporthe phaseolorum f.sp. meridionalis in different vegetative compatibility groups
Authors: Ploetz R. C. , Shores F. M.
Published: September 2008

Members of 1 of 29 previously described vegetative compatibility groups of Diaporthe phaseolorum f.sp. meridionalis (causal agent of soybean stem canker in the southeastern United States) predominated in epidemic populations from Alabama, Georgia, Florida, and Tennessee. Factors that might explain the prevalence of vegetative compatibility group (VCG) 1 were examined in studies with members of this and other VCGs of the pathogen. The virulence of isolates within six different VCGs on eight different soybean genotypes was similar, and variation among VCGs supported previous reports of diverse virulence in Diaporthe phaseolorum f.sp. meridionalis. Isolates within different VCGs also had similar in vitro growth rates and sensitivities to fungicides used either for controlling diseases of soybean in the Southeast (benomyl) or as an ingredient in a medium that is used to selectively isolate the pathogen (triadimefon). Since members of VCG 1 did not possess exceptional virulence, growth rates, or insensitivities to benomyl or triadimefon, the prevalence of VCG 1 could not be explained by these factors. However, relating these and other characteristics of Diaporthe phaseolorum f.sp. meridionalis to a biologically significant characteristic such as vegetative compatibility would provide a logical framework by which isolates and populations of the pathogen could be evaluated in future studies.
The watertight dormancy of Melilotus alba seeds: further observations on the palisade cell wall
Authors: Bevilacqua Letizia Riggio , Roti-Michelozzi Guidetta , Modenesi Paolo
Published: September 2008

The impermeable palisade layer of Melilotus alba seed coats was studied on sections, phytoglyphs, and separated cells obtained from them, using light and fluorescence microscopy. Occurrence of callose was demonstrated with sirofluor, the aniline blue fluorochrome, in the region of the light line and below it in the palisade cell wall. In the same region, a highly fluorescent material following phosphine 3R staining was evident. These results indicate that seed coat hardness is due not only to the caps or the light line of the palisade cells but also to the entire wall except for the inner tangential portion.
Sexual hybridization among Azolla species
Authors: Cat Do Van , Watanabe Iwao , Zimmerman W. J. , Lumpkin T. A. , Baillonville T. de Waha
Published: September 2008

Sexual hybridization, one of possible methods to improve agronomic traits of Azolla, was tried among Azolla filiculoides Lamarck, Azolla microphylla Kaulfuss, Azolla mexicana Presl., and Azolla pinnata R.Br. Crosses between A. filiculoides and A. microphylla were successful. Hybrids from A. microphylla (female) and A. filiculoides (male) were studied in detail. Electrophoresis of enzymes, shikimate dehydrogenase, phosphoglucomutase, and 6-phosphogluconate dehydrogenase, showed that enzyme loci of hybrids shared those of one or both parents. Hybrids produced only microsporocarps. Stem length of the hybrid was intermediate between those of both parents. Azolla filiculoides has longer stems than A. microphylla. Red color appeared in hybrids but not in both parents in the field and in the greenhouse under the P- or Ca-deficient condition. Fresh biomass production of hybrids at 37 °C: 29 °C 12-h light: 12-H dark was lower than that of A. microphylla and higher than that of A. filiculoides. The N content of hybrids was higher than that of A. microphylla. Growth of hybrids in the field was greater than that of A. microphylla strains, indicating positive heterosis. Key words: Azolla, Azolla filiculoides, Azolla microphylla, sexual hybridization, heterosis.
Mansonone accumulation in elm callus induced by elicitors of Ophiostoma ulmi, and general properties of elicitors
Authors: Yang D. , Jeng R. S. , Hubbes M.
Published: September 2008

Fungal culture filtrates, cytoplasm, and cell walls of Ophiostoma ulmi contain molecules that elicit mansonone (phytoalexin) accumulation in elm calli. The elicitors from nonaggressive isolate Q311 cause a more rapid reaction on bioassays than those from the aggressive isolate MH75. On the callus of a susceptible elm (Ulmus americana), the elicitors from both isolates cause higher amounts of mansonone production than on the callus of a resistant elm (Ulmus pumila). These elicitors are heat stable, and their eliciting activities are partially sensitive to NaIO4, pronase E, proteinase K, and various hydrolytic enzymes. However, β-glucosidase treated elicitors have increased eliciting activities. The binding of Q311 culture filtrate elicitors to a concanavalin A – sepharose 4B column suggests that glycoproteins may be involved in elicitation. Some abiotic factors stimulate only small amounts of mansonone F accumulation in treated elm cells.
Wintering forms of perennial herbs in the cool temperate regions of Japan
Authors: Yoshie Fumio , Yoshida Shizuo
Published: September 2008

Wintering forms of 42 perennial herbaceous species were investigated in the cool temperate regions of Japan. Three types of dormancy were recognized based on the number of days required for growth initiation at 24 °C: nondormant (< 8 days), shallow dormant (17–59 days), and deep dormant (> 300 days). The nondormant herbs overwinter under an imposed dormancy, as in biennials. The shallow-dormant herbs required a greater number of days for growth initiation as incubation temperature decreased and thereby could avoid unseasonal autumn sprouting. The deep-dormant herbs required the greatest number of days for growth initiation under a wide range of temperatures, and they seldom sprout new shoots during the unfavorable season. Three types of winter buds were recognized based on the degree of differentiation of scales from young foliage leaves: buds with no differentiated scales, buds with partially differentiated scales, and buds with perfectly differentiated scales. The herbs with perfectly differentiated scales tended to expand a small number of foliage leaves that were performed in the buds. Two contrasting wintering forms occurred in relation to habitats. The nondormant herbs with no differentiated scales on the groud surface (hemicryptophytes) were found in exposed habitats. The deep-dormant herbs with perfectly differentiated scales under the ground surface (geophytes) were found on the forest floor. The ecological implications of these wintering forms are discussed.
The effects of abscisic acid, kinetin, and gibberellin on freezing tolerance in smooth bromegrass (Bromus inermis) cell suspensions
Authors: Reaney Martin J. T. , Gusta Lawrence V. , Abrams Suzanne R. , Robertson Albert J.
Published: September 2008

The effects of kinetin and gibberellic acids (GA3, GA4, GA7, GA9, and a mixture of GA4,7,9) on cold hardening, dehardening, and growth of smooth bromegrass (Bromus inermis Leyss. cv. Manchar) suspension cultures treated with abscisic acid (ABA) were determined. Bromegrass cells treated with 75 μM racemic ABA for 7 days at 25 °C tolerated −37 °C, whereas cells treated with both racemic ABA (75 μM) and a mixture of GA4, GA7, and GA9 (total gibberellic acid concentration 100 μM) were similar in hardiness to the controls (LT50, −10 °C). GA4,7,9 at concentrations greater than 10 μM inhibited the growth of cells. Although 400 μM GA4,7,9 was lethal to cells, 75 μM ABA overcame the lethal effect but did not overcome growth inhibition. The twofold reduction in cell water content due to 75 μM ABA treatment for 7 days was partially overcome by GA4,7,9 at concentrations greater than 400 μM. GA4, GA7, and GA9 were equally effective at limiting growth and inhibiting freezing tolerance induced by ABA, whereas GA3 had little effect on cold hardiness, growth, and water content. During the first 4 days, kinetin at concentrations greater than 100 μM inhibited growth of both control cells and cells treated with ABA. Kinetin (> 100 μM) also inhibited freezing tolerance induced by abscisic acid after 4 days, but had no effect after 8 days. Bromegrass cells treated with 75 μM ABA for 7 days were hardened to −37 °C but dehardened to −12 °C after transfer to fresh medium minus ABA after 12 days at 10 °C. GA4,7,9 (40 μM) had no effect on the rate of dehardening, whereas kinetin increased the rate of dehardening.
RECENT CHARM RESULTS FROM CLEO-c
Authors:   for the CLEO Collaboration, THORNDIKE EDWARD H.
Published: September 2008

CLEO-c analyses on D+, D0, and Ds decays are described.
STATUS OF THE HADRONIC τ DETERMINATION OF Vus
Authors: MALTMAN K. , WOLFE C. E. , BANERJEE S. , RONEY M. , NUGENT I.
Published: September 2008

We update the extraction of Vus from hadronic τ decay data in light of recent BaBar and Belle results on the branching fractions of a number of important strange decay modes. A range of sum rule analyses is employed, particular attention being paid to those based on “non-spectral weights”, developed previously to bring the slow convergence of the relevant integrated D = 2 OPE series under improved control. Results from the various sum rules are in good agreement with one another, but ~ 3σ below expectations based on 3-family unitarity.
NEW INSIGHTS ON VECTOR MESONS: A DIALOG BETWEEN $f^{T}_{V}$ AND fV
Authors: CATÀ OSCAR
Published: September 2008

We examine the high energy behavior of the two-point correlators 〈VV〉, 〈TT〉, 〈VT〉 and its implications on the spectrum of spin-1 vector mesons. This leads to an estimate of [Formula: see text] in excellent agreement with the recent sum rule and lattice determinations. This information is later implemented in a hadronic model and used to estimate the value of the magnetic susceptibility of the quark condensate χ0. Our analysis shows that lowest meson resonance may turn out to be a bad approximation for this quantity.
RECENT BABAR RESULTS ON B DECAYS
Authors:   for the BABAR Collaboration, CLARK P. J.
Published: September 2008

Several recent key results from the BABAR experiment are presented, most using 383.6 fb−1 of data. In particular, the search for B+ → τ+ν, inclusive and exclusive measurements of |Vub|, measurements of b → dγ decays and new observations of rare charmless hadronic decays. The new results provide important experimental constraints on the Standard Model and new physics models.
RECENT PROGRESS IN QCD FACTORIZATION FOR B → M1M2
Authors: YANG DESHAN
Published: September 2008

After briefly introducing the framework of QCD factorization for B → M1M2 in the language of the Soft-Collinear Effective Theory, we firstly address the recent efforts on higher-order radiative corrections in QCD factorization. Then we discuss some phenomenologies in B → VV within the framework of QCD factorization.
GENERALIZED ANALYSIS ON B → K*ρ WITHIN AND BEYOND THE STANDARD MODEL
Authors: KIM C. S. , OH SECHUL , SHARMA CHANDRADEW , SINHA RAHUL , YOON YEO WOONG
Published: September 2008

We study B → K*ρ modes that are analogues of the much studied B → Kπ modes with B decaying to two vector mesons instead of pseudoscalar mesons, using topological amplitudes in the quark diagram approach. All the theoretical parameters (except for the weak phase γ), such as the magnitudes of the topological amplitudes and their strong phases, can be determined in terms of the observables without any model-dependent assumption. We demonstrate how B → K*ρ can also be used to verify if there exist any relations between theoretical parameters, such as the hierarchy relations between the topological amplitudes and possible relations between the strong phases. Conversely, if there exist reliable theoretical estimates of amplitudes and strong phases, the presence of New Physics could be probed. We show that if the tree and color-suppressed tree are related to the electroweak penguins and color-suppressed electroweak penguins, it is not only possible to verify the validity of such relations but also to have a clean measurement of New Physics parameters. We also present a numerical study to examine which of the observables are more sensitive to New Physics.
RECENT BELLE RESULTS ON CP VIOLATION
Authors: OLSEN STEPHEN L.
Published: September 2008

The Belle experiment's recent results on CP violation in B meson decays are summarized.
CKM PHASE AND SPONTANEOUS CP VIOLATION
Authors: HE XIAO-GANG
Published: September 2008

The Standard Model for CP violation, the CKM model, works very well in explaining all laboratory experimental data. However, this model does not address the question that where it comes from. The origin of CP violation is still a mystery. In this talk I discuss a model1 addressing this problem in which the CP violating phase in the CKM matrix is identical to the phase in the Higgs potential resulting from spontaneous CP violation.
DIRECT CP AND T VIOLATION IN BARYONIC B DECAYS
Authors: GENG C. Q. , HSIAO Y. K.
Published: September 2008

We review the direct CP and T violation in the three-body baryonic B decays in the standard model. In particular, we emphasize that the direct CP violating asymmetry in [Formula: see text] is around 22% and the direct T violating asymmetry in [Formula: see text] can be as large as 12%, which are accessible to the current B factories at KEK and SLAC as well as SuperB and LHCb.
IS THERE ANY PUZZLE OF NEW PHYSICS IN B → Kπ DECAYS?
Authors: KIM C. S. , OH SECHUL , YOON YEO WOONG
Published: September 2008

Due to re-parametrization invariance of decay amplitudes, any single new physics (NP) amplitude arising through either the electro-weak penguin (EWP) or the color-suppressed tree amplitude can be embedded simultaneously into both the color-suppressed tree and the EWP contribution in B → Kπ decays. We present a systematic method to extract each standard model (SM)-like hadronic parameter as well as new physics parameters in analytic way, so that one can pinpoint them once experimental data are given. Using the currently available experimental data for B → Kπ modes, we find two possible analytic results: one showing the large SM-like color-suppressed tree contribution and the other showing the large SM-like EWP contribution. The magnitude of the NP amplitude and its weak phase are quite large. For instance, we find |PNP/P′| = 0.39 ± 0.13, φNP = 92° ± 15° and δNP = 7° ± 26°, which are the ratio of the NP-to-SM contribution, the weak and the strong phase of the NP amplitude, respectively. We also investigate the dependence of the NP contribution on the weak phase γ and the mixing induced CP asymmetry of B0 → KSπ0, respectively
A TWO HIGGS BI-DOUBLET LEFT-RIGHT MODEL WITH SPONTANEOUS CP VIOLATION
Authors: WU YUE-LIANG , ZHOU YU-FENG
Published: September 2008

We discuss a left-right symmetric model with two Higgs bi-doublet and spontaneous P and CP violation. The flavor changing neutral currents is suppressed by assuming approximate global U(1) family symmetry. We calculate the constraints from neural K meson mass difference ΔmK and demonstrate that a right-handed gauge boson W2 contribution in box-diagrams with mass around 600 GeV is allowed due to a negative interference with a light charged Higgs boson around 150 ~ 300 GeV. The W2 contribution to ɛK is suppressed from appropriate choice of additional CP phases appearing in the right-handed Cabbibo-Kobayashi-Maskawa(CKM) matrix. The model is found fully consistent with B0 mass difference and the mixing-induced CP asymmetry measurements.
RECENT THEORETICAL RESULTS IN HEAVY FLAVOUR PRODUCTION
Authors: KRAMER G.
Published: September 2008

We review one-particle inclusive production of heavy-flavored hadrons in a framework which resums the large collinear logarithms through the evolution of the FFs and PDFs and retains the full dependence on the heavy-quark mass. We focus on presenting results for the inclusive cross section for the production of charmed mesons in [Formula: see text] collisions and the comparison with CDF data as well as on inclusive B-meson production and comparison with recent CDF data, for which in both new determined fragmentation functions have been used.
RECENT RESULTS OF SNO EXPERIMENT
Authors:   for the SNO Collaboration, ZHANG FENG
Published: September 2008

This article provides a brief introduction to the recent results of the Sudbury Neutrino Observatory (SNO).
A4 SYMMETRY AND NEUTRINOS
Authors: MA ERNEST
Published: September 2008

I recount briefly the history of neutrino tribimaximal mixing and the use of the discrete family symmetry A 4 in obtaining it.
SO(3) GAUGE SYMMETRY AND NEARLY TRI-BIMAXIMAL NEUTRINO MIXING
Authors: WU YUE-LIANG
Published: September 2008

In this note I mainly focus on the neutrino physics part in my talk and report the most recent progress made in 1. It is seen that the Majorana features of neutrinos and SO (3) gauge flavor symmetry can simultaneously explain the smallness of neutrino masses and nearly tri-bimaximal neutrino mixing when combining together with the mechanism of approximate global U (1) family symmetry. The mixing angle θ13 and CP-violating phase are in general nonzero and testable experimentally at the allowed sensitivity. The model also predicts the existence of vector-like Majorana neutrinos and charged leptons as well as new Higgs bosons, some of them can be light and explored at the LHC and ILC.
THE MINIMAL TYPE-II SEESAW MODEL AND FLAVOR-DEPENDENT LEPTOGENESIS
Authors: LUO SHU , XING ZHI-ZHONG
Published: September 2008

Current experimental data allow the zero value for one neutrino mass, either m1 = 0 or m3 = 0. This observation implies that a realistic neutrino mass texture can be established by starting from the limit (a) m1 = m2 = 0 and m3 ≠ 0 or (b) m1 = m2 ≠ 0 and m3 = 0. In both cases, we may introduce a particular perturbation which ensures the resultant neutrino mixing matrix to be the tri-bimaximal mixing pattern or its viable variations. We find that it is natural to incorporate this kind of neutrino mass matrix in the minimal Type-II seesaw model with only one heavy right-handed Majorana neutrino N. We show that it is possible to account for the cosmological baryon number asymmetry in the m3 = 0 case via thermal leptogenesis, in which the CP-violating asymmetry of N decays is attributed to the electron flavor.
LOW SCALE LEPTOGENESIS AND DARK MATTER CANDIDATES IN AN EXTENDED SEESAW MODEL
Authors: KIM C. S. , KANG SIN KYU , CHEON H. SUNG
Published: September 2008

We consider a variant of seesaw mechanism by introducing extra singlet neutrinos and singlet scalar boson, and show how low scale leptogenesis is successfully realized in this scenario. We examine if the newly introduced neutral particles, either singlet Majorana neutrino or singlet scalar boson, can be a candidate for dark matter. We also discuss the implications of the dark matter detection through the scattering off the nucleus of the detecting material on our scenarios for dark matter.
SURGERY DESCRIPTIONS AND VOLUMES OF BERGE KNOTS II: DESCRIPTIONS ON THE MINIMALLY TWISTED FIVE CHAIN LINK
Authors: BAKER KENNETH L.
Published: September 2008

Using Kirby calculus, we explicitly pass from Berge's R-R descriptions of ten families of knots with lens space surgeries to surgery descriptions on the minimally twisted five chain link (MT5C). Since the MT5C admits a strong inversion, we also give the corresponding tangle descriptions.
Performance and Investments in China from Industrial Perspectives: Evidence from Taiwan Firms
Authors: Chiang Yi-Chein , Liao Tung Liang , Liu Yu-Ling
Published: September 2008

This study examines direct investments of Taiwan firms in China (DIC) and firm performance consequences from industrial perspectives. It is found that a U-shaped relationship exists for electronic firms but an inverted-S-shaped relationship exists for non-electronic firms. The empirical results also reveal that electronic firms outperform non-electronic firms.
An Empirical Study on the Long-Run Determinants of Exchange Rate
Authors: Chiu I-Ming
Published: September 2008

The behavior of exchange rates has been an important issue in the international finance literature. Although exchange rate is erratic and unpredictable in the short run, its long-run behavior is believed to be guided by economic fundamentals. This paper empirically tests the long-run determinants of the exchange rate by focusing on the Taiwan/US case. After incorporating productivity differential, foreign reserves, and monetary base in the absolute Purchasing Power Parity (PPP) proposition, where the relative price is the only determinant of the exchange rate, the Johansen's maximum likelihood test results indicate these determinants and the exchange rate are indeed cointegrated: thus a long-run relationship can be established.
Valuing IPOs Using Price-Earnings Multiples Disclosed by IPO Firms in an Emerging Capital Market
Authors: Firth Michael , Li Yue , Wang Steven Shuye
Published: September 2008

Existing studies show that markets use comparable firm multiples to price IPOs. This study explores IPO valuations in an emerging market where reliable comparable price multiples may not be readily available, or cannot be reliably identified. In particular, we examine the value relevance of price-earnings multiples disclosed by managers in IPO prospectuses in China. Using a sample of IPOs from 1992 to 2002, we find that price-earnings multiples disclosed by IPO firms provide significant power in explaining price formation in this emerging market. We also find that price-earnings multiples disclosed by IPO firms after 1999, when the China Securities and Regulatory Commission relaxed its internal guideline for approving IPO applications, are more informative. The results are robust to a variety of empirical model specifications. This study contributes to the existing IPO literature by showing that the disclosure of price-earnings multiples provides a mechanism for IPO firms to convey information about IPO firm quality when reliable comparable firm multiples may not exist.
Subprime Mortgages, Market Impact, and Safety Nets
Authors: Watson Ronald D.
Published: September 2008

The US financial system is undergoing a painful restructuring as credit losses originating in the mortgage finance sector of the economy grow ever larger. A combination of factors including general prosperity, demographic shifts in demand for housing, low interest rates, innovations in mortgage lending and securitization, and a breakdown in credit quality control systems all contributed to this problem. Public policymakers and industry leaders are struggling to find ways to stem the credit losses, restructure and recapitalize the financial industry, and set the economy on a path to recovery. This paper reviews the origins of this problem, explains the events that precipitated the crisis in 2007, and analyzes the pros and cons of the "fixes" that have been proposed to address these problems.
GLOBAL STABILITY OF A STAGE-STRUCTURED PREDATOR-PREY SYSTEM
Authors: SONG XINYU , GUO HONGJIAN
Published: September 2008

In this paper, we consider a predator-prey system with stage structure. The populations have two stages, an immature stage and a mature stage, the age to maturity is represented by a time delay, which leads to systems of retarded functional differential equations. We obtain the conditions for global asymptotic stability of two nonnegative equilibria of this system. The numerical simulation suggests that time delay has both oscillatory dynamics and stabilizing effects.
Prepubertal OVX increases IGF-I expression and bone accretion in C57BL/6J mice
Authors: Govoni Kristen E. , Wergedal Jon E. , Chadwick Robert B. , Srivastava Apurva K. , Mohan Subburaman
Published: September 2008

It is generally well accepted that the pubertal surge in estrogen is responsible for the rapid bone accretion that occurs during puberty and that this effect is mediated by an estrogen-induced increase in growth hormone (GH)/insulin-like growth factor (IGF) action. To test the cause and effect relationship between estrogen and GH/IGF, we evaluated the consequence of ovariectomy (OVX) in prepubertal mice (C57BL/6J mice at 3 wk of age) on skeletal changes and the GH/IGF axis during puberty. Contrary to our expectations, OVX increased body weight (12–18%), bone mineral content (11%), bone length (4%), bone size (3%), and serum, liver, and bone IGF-I (30–50%) and decreased total body fat (18%) at 3 wk postsurgery. To determine whether estrogen is the key ovarian factor responsible for these changes, we performed a second experiment in which OVX mice were treated with placebo or estrogen implants. In addition to observing similar results compared with our first experiment, estrogen treatment partially rescued the increased body weight and bone size and completely rescued body fat and IGF-I levels. The increased bone accretion in OVX mice was due to increased bone formation rate (as determined by bone histomorphometry) and increased serum procollagen peptide. In conclusion, contrary to the known estrogen effect as an initiator of GH/IGF surge and thereby pubertal growth spurt, our findings demonstrate that loss of estrogen and/or other hormones during the prepubertal growth period effect leads to an increase in IGF-I production and bone accretion in mice.
Emerging roles for the ubiquitin-proteasome system and autophagy in pancreatic β-cells
Authors: Hartley Taila , Brumell John , Volchuk Allen
Published: September 2008

Protein degradation in eukaryotic cells is mediated primarily by the ubiquitin-proteasome system and autophagy. Turnover of protein aggregates and other cytoplasmic components, including organelles, is another function attributed to autophagy. The ubiquitin-proteasome system and autophagy are essential for normal cell function but under certain pathological conditions can be overwhelmed, which can lead to adverse effects in cells. In this review we will focus primarily on the insulin-producing pancreatic β-cell. Pancreatic β-cells respond to glucose levels by both producing and secreting insulin. The inability of β-cells to secrete sufficient insulin is a major contributory factor in the development of type 2 diabetes. The aim of this review is to examine some of the crucial roles of the ubiquitin-proteasome system and autophagy in normal pancreatic β-cell function and how these pathways may become dysfunctional under pathological conditions associated with metabolic syndromes.
Evaluating the glucose tolerance test in mice
Authors: Andrikopoulos Sofianos , Blair Amy R. , Deluca Nadia , Fam Barbara C. , Proietto Joseph
Published: September 2008

The objective of this study was to determine the optimal conditions under which to assess glucose tolerance in chow- and high-fat-fed C57BL/6J mice. Mice were fed either chow or high-fat diet for 8 wk. Variables tested were fasting duration (0-, 3-, 6-, and 24-h and overnight fasting), route of administration (intraperitoneal vs. oral) load of glucose given (2, 1, or 0.5 g/kg and fixed 50-mg dose), and state of consciousness. Basal glucose concentrations were increased in high-fat- compared with chow-fed mice following 6 h of fasting (9.1 ± 0.3 vs. 7.9 ± 0.4 mmol/l P = 0.01). Glucose tolerance was most different and therefore significant ( P = 0.001) in high-fat-fed mice after 6 h of fasting (1,973 ± 96 vs. 1,248 ± 83 mmol·l−1·120 min−1). The difference in glucose tolerance was greater following an OGTT (142%), in contrast to an IPGTT, with a 127% difference between high fat and chow. We also found that administering 2 g/kg of glucose resulted in a greater level of significance ( P = 0.0008) in glucose intolerance in high-fat- compared with chow-fed mice. A fixed dose of 50 mg glucose regardless of body weight was enough to show glucose intolerance in high-fat- vs. chow-fed mice. Finally, high-fat-fed mice showed glucose intolerance compared with their chow-fed counterparts whether they were tested under conscious or anesthetized conditions. We conclude that 2 g/kg glucose administered orally following 6 h of fasting is best to assess glucose tolerance in mice under these conditions.
High glucose increases the expression of Gq/11α and PLC-β proteins and associated signaling in vascular smooth muscle cells
Authors: Descorbeth Magda , Anand-Srivastava Madhu B.
Published: September 2008

The levels and activity of protein kinase C and diacylglycerol were shown to be upregulated in diabetes/hyperglycemia; however, studies on the expression of upstream signaling molecules of phosphatidylinositol turnover were lacking. The present study was therefore undertaken to examine whether hyperglycemia/diabetes could also modulate the expression of Gqα and phospholipase C-β (PLC-β) proteins and associated phosphatidylinositol turnover signaling in aortic vascular smooth muscle cells (VSMCs) and A10 VSMCs exposed to high glucose. Aortic VSMCs from streptozotocin-diabetic rats exhibited an increased expression of Gqα and PLC-β1 proteins (60% and 30%, respectively) compared with control cells as determined by Western blot analysis. The pretreatment of A10 VSMCs with high glucose (26 mM) for 3 days also augmented the levels of Gqα, G11α, PLC-β1 and -β2 proteins by about 50, 35, 30, and 30%, respectively, compared with control cells that were restored to control levels by endothelin-1 (ET-1), ET types A and B (ETA and ETB) receptors, and angiotensin II type 1 (AT1) receptor antagonists. In addition, ET-1-stimulated inositol triphosphate formation was also significantly higher in VSMCs exposed to high glucose, whereas the basal levels of inositol triphosphate were not different between the two groups. Furthermore, the treatment of A10 VSMCs with angiotensin II and ET-1 also significantly increased the levels of Gq/11α and PLC-β proteins that were restored toward control levels by ETA/ETB and AT1 receptor antagonists. These results suggest that high glucose augments the expression of Gq/11α, PLC-β, and mediated signaling in VSMCs, which may be attributed to AT1, ETA, and ETB receptors.
Changes in brain mRNA levels of gonadotropin-releasing hormone, pituitary adenylate cyclase activating polypeptide, and somatostatin during ovulatory luteinizing hormone and growth hormone surges in goldfish
Authors: Canosa Luis Fabián , Stacey Norm , Peter Richard Ector
Published: September 2008

In goldfish, circulating LH and growth hormone (GH) levels surge at the time of ovulation. In the present study, changes in gene expression of salmon gonadotropin-releasing hormone (sGnRH), chicken GnRH-II (cGnRH-II), somatostatin (SS) and pituitary adenylate cyclase activating polypeptide (PACAP) were analyzed during temperature- and spawning substrate-induced ovulation in goldfish. The results demonstrated that increases in PACAP gene expression during ovulation are best correlated with the GH secretion profile. These results suggest that PACAP, instead of GnRH, is involved in the control of GH secretion during ovulation. Increases of two of the SS transcripts during ovulation are interpreted as the activation of a negative feedback mechanism triggered by high GH levels. The results showed a differential regulation of sGnRH and cGnRH-II gene expression during ovulation, suggesting that sGnRH controls LH secretion, whereas cGnRH-II correlates best with spawning behavior. This conclusion is further supported by the finding that nonovulated fish induced to perform spawning behavior by prostaglandin F2α treatment increased cGnRH-II expression in both forebrain and midbrain, but decreased sGnRH expression in the forebrain.
Mapping of quantitative trait loci for cholesterol, LDL, HDL, and triglyceride serum concentrations in pigs
Authors: Gallardo David , Pena Ramona N. , Amills Marcel , Varona Luis , Ramírez Oscar , Reixach Josep , Díaz Isabel , Tibau Joan , Soler Joaquim , Prat-Cuffi Josep M. , Noguera José L. , Quintanilla Raquel
Published: September 2008

The fine mapping of polymorphisms influencing cholesterol (CT), triglyceride (TG), and lipoprotein serum levels in human and mouse has provided a wealth of knowledge about the complex genetic architecture of these traits. The extension of these genetic analyses to pigs would be of utmost importance since they constitute a valuable biological and clinical model for the study of coronary artery disease and myocardial infarction. In the present work, we performed a whole genome scan for serum lipid traits in a half-sib Duroc pig population of 350 individuals. Phenotypic registers included total CT, TG, and low (LDL)- and high (HDL)-density lipoprotein serum concentrations at 45 and 190 days of age. This approach allowed us to identify two genomewide significant quantitative trait loci (QTL) for HDL-to-LDL ratio at 45 days (SSC6, 84 cM) and for TG at 190 days (SSC4, 23 cM) as well as a number of chromosomewide significant QTL. The comparison of QTL locations at 45 and 190 days revealed a notable lack of concordance at these two time points, suggesting that the effects of these QTL are age specific. Moreover, we have observed a considerable level of correspondence among the locations of the most significant porcine lipid QTL and those identified in humans. This finding might suggest that, in mammals, diverse polymorphisms located in a common set of genes are involved in the genetic variation of serum lipid levels.
Hypothalamus transcriptome profile suggests an anorexia-cachexia syndrome in the anx/anx mouse model
Authors: Mercader Josep Maria , Lozano Juan José , Sumoy Lauro , Dierssen Mara , Visa Joana , Gratacòs Mònica , Estivill Xavier
Published: September 2008

The anx/anx mouse displays poor appetite and lean appearance and is considered a good model for the study of anorexia nervosa. To identify new genes involved in feeding behavior and body weight regulation we performed an expression profiling in the hypothalamus of the anx/anx mice. Using commercial microarrays we detected 156 differentially expressed genes and validated 92 of those using TaqMan low-density arrays. The expression of a set of 87 candidate genes selected based on literature evidences was also quantified by TaqMan low-density arrays. Our results showed enrichment in deregulated genes involved in cell death, cell morphology, and cancer, as well as an alteration of several signaling circuits involved in energy balance including neuropeptide Y and melanocortin signaling. The expression profile along with the phenotype led us to conclude that anx/anx mice resemble the anorexia-cachexia syndrome typically observed in cancer, infection with human immunodeficiency virus or chronic diseases, rather than starvation, and that anx/anx mice could be considered a good model for the treatment and investigation of this condition.
Progesterone Receptor-B Regulation of Insulin-Like Growth Factor–Stimulated Cell Migration in Breast Cancer Cells via Insulin Receptor Substrate-2
Authors: Ibrahim Yasir H. , Byron Sara A. , Cui Xiaojiang , Lee Adrian V. , Yee Douglas
Published: September 2008

Progesterone action contributes to the signaling of many growth factor pathways relevant to breast cancer tumor biology, including the insulin-like growth factor (IGF) system. Previous work has shown that insulin receptor substrate-2 (IRS-2) but not IRS-1 levels were regulated by progestin in progesterone receptor-B (PR-B) isoform expressing MCF-7 cells (C4-12 PR-B). Furthermore, type 1 IGF receptor (IGF1R) signaling via IRS-2 correlated with the increased cell migration observed in a number of breast cancer cell lines. Consequently, in this study, we examined whether the elevation of IRS-2 protein induced by progestin was sufficient to promote IGF-I–stimulated cell motility. Treatment of C4-12 PR-B cells with progestin shifted the balance of phosphorylation from IRS-1 to IRS-2 in response to IGF-I. This shift in IRS-2 activation was associated with enhanced migration in C4-12 PR-B cells pretreated with progestin, but had no effect on cell proliferation or survival. Treatment of C4-12 PR-B cells with RU486, an antiprogestin, inhibited IGF-induced cell migration. Attenuation of IRS-2 expression using small interfering RNA resulted in decreased IGF-stimulated motility. In addition, IRS-2 knockdown resulted in an abrogation of PKB/Akt phosphorylation but not mitogen-activated protein kinase. Consequently, LY294002, a phosphoinositide-3-kinase inhibitor, abolished IGF-induced cell motility in progestin-treated C4-12 PR-B cells. These data show a role for the PR in functionally promoting growth factor signaling, showing that levels of IRS proteins can determine IGF-mediated biology, PR-B signaling regulates IRS-2 expression, and that IRS-2 can mediate IGF-induced cell migration via phosphoinositide-3-kinase in breast cancer cells. (Mol Cancer Res 2008;6(9):1491–8)
Imaging Techniques in Acute Kidney Injury
Authors: Sharfuddin Asif A. , Sandoval Ruben M. , Molitoris Bruce A.
Published: September 2008

Multi-photon microscopy, along with advances in other imaging modalities, allows investigators the opportunity to study dynamic events within the functioning kidney. These emerging technologies enable investigators to follow complex heterogeneous processes in organs such as the kidney with improved spatial and temporal resolution, and sensitivity. Furthermore, the ability to obtain volumetric data (3-D) makes quantitative 4-D (time) analysis possible. Finally, use of up to three fluorophores concurrently in multi-photon microscopy allows for three different or interactive processes to be observed simultaneously. Therefore, this approach complements existing molecular, biochemical, pharmacologic and radiologic techniques by advancing data analysis and interpretation to subcellular levels for molecules without the requirement for fixation. Its use in acute kidney injury is in its infancy but offers much promise for unraveling the complex interdependent processes known to contribute to cell injury and organ failure. Also, recent advances in other imaging techniques offer potential clinical diagnostic tools to study acute kidney injury in animal models and in patients.