bluuebunny/crossref_metadata_2025 huggingface dataset:
Difference frequency mixing of strongly focused Gaussian beams in periodically poled LiNbO3
Authors: Abu-Safe Husam H.
Published: June 2005

Difference frequency mixing of strongly focused Gaussian beams in periodically poled LiNbO3 was investigated. The beams were focused inside the crystal without damage. Mixing of cw and pulsed laser systems was employed to minimize the thermal lensing effects inside this crystal. A low-power cw 1.064-μm Nd:YAG laser beam was used as the pump, whereas the signal beam came from a picosecond optical parametric oscillator. The two independently focused beams were made to overlap inside the crystal. The focusing parameters of the two beams were about the same. The focusing function developed by Boyd and Kleinman for tightly focused beams was extended to periodically poled crystals in order to fit the temperature-tuning curve. A 0.66%∕W efficiency was obtained for the difference frequency mixing process.
Thermally activated switching in spin-flop tunnel junctions
Authors: Korenivski V. , Worledge D. C.
Published: June 2005

Magnetic tunnel junctions with a flux-closed sandwich replacing the single-soft layer have been proposed for increasing the magnetic stability of the junctions. Such flux-closed soft layers have two antiferromagnetic ground states and reverse by spin-flop switching. They are expected to essentially eliminate the critical issue of thermally activated reversal under half-select fields and ease the scaling of the emerging technology of magnetic random access memory. High-speed pulse measurements of such submicron spin-flop junctions performed over nine decades in time are reported here. The switching probability as a function of the pulse field amplitude and duration is analyzed to estimate the energy barrier to thermal activation. This activation energy is found to be substantially enhanced compared to the single-free layer case, and agrees well with the single-domain model prediction.
Dipole radio-frequency power from laser plasmas with no dipole moment
Authors: Felber F. S.
Published: June 2005

The radio-frequency power radiated from laser-target plasmas in a vacuum can be orders of magnitude greater than expected from such sources that have a negligible electric dipole moment. A model combining the Tidman–Stamper circuit model of a laser-target plasma with the theory of radiation from currents immersed in plasmas, however, predicts scaling of electric-dipole power radiated from laser plasmas in agreement with experiments.
Observation of visible luminescence from indium nitride at room temperature
Authors: Guo Q. X. , Tanaka T. , Nishio M. , Ogawa H. , Pu X. D. , Shen W. Z.
Published: June 2005

InN films were grown on sapphire substrates with AlN buffer layers by reactive sputtering. C-axis-oriented crystalline InN films with a wurtzite structure were confirmed by x-ray diffraction and Raman scattering. Strong photoluminescence (PL) at 1.87 eV, together with a clear absorption edge at 1.97 eV, was observed at room temperature, which clearly demonstrates that it is not accurate in the previous assignment of an ∼0.7eV fundamental band gap for intrinsic InN simply from PL and absorption data. The possible origin of the present large band gap was discussed in terms of the effects of oxygen and the Burstein-Moss shift.
High-density vertically aligned multiwalled carbon nanotubes with tubular structures
Authors: Kayastha Vijaya Kumar , Yap Yoke Khin , Pan Zhengwei , Ivanov Ilia N. , Puretzky Alex A. , Geohegan David B.
Published: June 2005

Ammonia (NH3) gas was thought to be essential for the growth of vertically aligned multiwalled carbon nanotubes (VA-MWCNTs) and led to the formation of bamboo-like structures. Here, we show that VA-MWCNTs with ideal tubular structures can be grown on substrates by various mixed gases with or without NH3 gas. The growth of these VA-MWCNTs is guided by a growth model that combined the dissociative adsorption of acetylene molecules (C2H2) and the successive vapor-liquid-solid growth mechanism. Results indicate that the key factor for growing these VA-MWCNTs is a balance between the decomposition rate of the C2H2 molecules on the iron catalyst and the subsequent diffusion and segregation rates of carbon.
Effect of hydration on the structure of oriented lipid membranes investigated by in situ time-resolved energy dispersive x-ray diffraction
Authors: Caminiti Ruggero , Caracciolo Giulio , Pisani Michela
Published: June 2005

In situ time-resolved energy dispersive x-ray diffraction (EDXD) was applied to investigate the effect of hydration on the structure of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)-oriented membranes. The measurements allowed a very high density time sampling of the evolution of the structural properties of the DOTAP bilayer such as the lamellar d-spacing, the membrane thickness, and the size of the interbilayer water region. Time-resolved EDXD has been found to provide important information on the role played by free water molecules on the structure and fluidity of lipid bilayer.
Assembly and characterization of hybrid virus-inorganic nanotubes
Authors: Liu W. L. , Alim K. , Balandin A. A. , Mathews D. M. , Dodds J. A.
Published: June 2005

Recently, rod-shaped viruses have attracted attention as biological templates for assembly of nanostructures. Tobamoviruses such as the type strain of Tobacco mosaic virus (TMV-U1, or -common) have a cylindrical shape and dimensions suitable for nanoelectronic applications: 300nm long and 18nm in diameter with a 4nm axial channel. TMV particles can be coated with metals, silica, or semiconductor materials and may also form end-to-end assemblies to be used as interconnects or device channels. In this letter, we report the preparation of TMV-U1 templated organic-metal nanotubes, and their structural characterization using transmission electron microscopy and micro-Raman spectroscopy. Reproducible phonon signatures different from that of native TMV-U1 were observed from the metal-coated TMVs. Our results indicate that Raman spectroscopy can be used for monitoring of the bio-assisted nanostructure assembly and for analyzing the vibrational modes of the resulting bio-inorganic junctions.
Surface-plasmon polariton scattering from a finite array of nanogrooves∕ridges: Efficient mirrors
Authors: Sánchez-Gil José A. , Maradudin Alexei A.
Published: June 2005

The scattering of surface-plasmon polaritons (SPP) by finite arrays of one-dimensional nanodefects on metal surfaces is theoretically investigated on the basis of the reduced Rayleigh equation. Numerical calculations are carried out that rigorously account for all the scattering channels: SPP reflection and transmission, and radiative leakage. We analyze the range of parameters (defect size and number) for which high SPP reflection efficiency (low radiative losses) is achieved within a SPP band gap (negligible SPP transmission), neglecting ohmic losses (justified for array lengths significantly shorter than the SPP inelastic length): Smaller defects play better as SPP mirrors (e.g., efficiency >90% at λ∼650nm for Gaussian ridges∕grooves with sub-30nm height and half-width) than larger defects, since the latter yield significant radiative losses.
High-resolution transmission electron microscopy mapping of nickel and cobalt single-crystalline nanorods inside multiwalled carbon nanotubes and chirality calculations
Authors: Tyagi Pawan K. , Misra Abha , Singh Manoj K. , Misra D. S. , Ghatak Jay , Satyam P. V. , Le Normand F.
Published: June 2005

The nickel and cobalt nanorods of the diameters in the range of 6–20nm with lengths of 0.29–0.9μm are formed using multiwalled carbon nanotubes as templates. The nickel and cobalt nanorods as described in our letter are perfect single crystals inside the nanotube with their Miller planes inclined with respect to the tube axis in a particular fashion. The (111) planes of face-centered-cubic nickel and cobalt are inclined at angles 39.6° and 39.4°, respectively, while the hexagonal-closed-packed cobalt (002) planes incline at an angle 53.4°. The inclination of these planes is studied in detail and results are discussed in terms of elastic energy and surface tension. The chirality of the carbon nanotubes, in intimate contact with the nanorod, is determined using the mapping of Ni and C atoms in a graphene sheet. We believe this could pave a way for synthesizing the tubes with known chirality.
Temperature dependence of the giant magnetostrain in a NiMnGa magnetic shape memory alloy
Authors: Jiang Chengbao , Wang Jingmin , Xu Huibin
Published: June 2005

The temperature dependence of the magnetostrain was investigated in the Ni50Mn27.5Ga22.5 magnetic shape memory alloy with a five-layer martensitic (5M) structure in the temperature range from 110Kto300K. A temperature threshold at 166K was found for the magnetostrain. A giant magnetostrain of 6.3% was achieved above the temperature, while no magnetostrain was monitored below the temperature. No intermartensitic transformation was detected around the temperature threshold. The lattice parameter a slightly increases, c largely decreases, and the tetragonality (a∕c−1) drastically increases with decreasing the temperature. The increase of the tetragonality is thought to be related to the temperature threshold of the magnetostrain by inducing a change of the electronic structure, twin structure, or the type of the variant with the same 5M martensitic structure below the temperature threshold. The interpretation is reasonably understood by the fact that only few samples with the same 5M martensitic structure exhibit a giant magnetostrain.
Structural modifications induced by Eutypa lata in the xylem of trunk and canes of Vitis vinifera
Authors: Rudelle Jérome , Octave Stéphane , Kaid-Harche Meriem , Roblin Gabriel , Fleurat-Lessard Pierrette
Published: June 2005

Eutypa dieback, a devastating disease in grapevines, is caused by the fungal pathogen Eutypa lata, a wood-inhabiting fungus. E. lata acts by degrading wood tissues in the colonisation areas, and produces foliar symptoms. These striking symptoms have been attributed to the production of toxic metabolites by the pathogen, the most widely studied being eutypine. The aims of the study were to compare the effects of E. lata on xylem structure at the site of infection and in remote tissues. In healthy Vitis vinifera, the vessel-associated cells (VACs) in the trunk have a protective layer that covers the entire lignified wall and forms a transfer apparatus in pits located at the VAC / vessel interface. This apparatus occurs similarly in VACs in the basal part of canes but is less developed in the apical part. In the presence of E. lata, which is found only in the trunk and the cordons, the VACs initiated a program of secretory activity that led to the enlargement of the transfer apparatus, which is formed by tightly associated fibrils. This secretory activity was followed by VAC death. Furthermore, the hypertrophy of the transfer apparatus spread according to an acropetal gradient in the canes. Treatment with eutypine also induced the development of the transfer apparatus in VACs of basal and apical parts of canes excised from healthy vines. However, this apparatus was formed by loosely packed fibrils in VACs that were not completely damaged. Therefore, metabolites other than eutypine are expected to be involved in the VAC degeneration observed in infected vines.
The Occurrence of the White-Tailed Black Cockatoo, Calyptorhynchus baudinii, in Pinus Plantations in Western Australia
Authors: Saunders DA
Published: June 2005

The occurrence of C. baudinii in pine plantations near Perth in Western Australia was surveyed from 1965 to 1970. Results were compared with earlier observations of cockatoo numbers in Mundaring pine plantation and with observations of birds in jarrah forest near Mt Helena.
The birds regularly concentrated in plantations near Perth after the breeding season, completely stripping the cones from the small plantations before moving out to the other larger plantations north of Perth. In contrast, in eucalypt forests they occurred irregularly and in smaller numbers.
Observations were made on the way the birds drop uneaten pine cones and green twigs while feeding. Pine cones are similar to fruits of native species regularly eaten by cockatoos.
Subspeciation in the White-tailed Black Cockatoo, Calyptorhynchus baudinii, in Western Australia
Authors: Saunders DA
Published: June 2005

The nomenclatural history of the two forms of white-tailed black cockatoo is discussed.
Their correct names are Calyptorhynchus baudinii baudinii Lear for the long-billed form, and C. b. latirostris Carnaby for the short-billed form.
C. b. latirostris differs from baudinii in having a slightly shorter wing and shorter culmen, there being virtually no overlap in the range of culmen lengths between adults of the two subspecies. The adult skull of baudinii is wider and higher, with a longer culmen, lower mandible and gonys than latirostris. C. b. baudinii is found in areas with an annual average rainfall of 750 mm or more, whereas lativostris occurs where it is 300–750 mm. C. b. baudinii appears to be resident throughout the year whereas latirostris moves to the higher-rainfall areas during the non-breeding season, returning to the drier areas during the breeding season. For food baudinii depends on the seeds of the marri, Eucalyptus calophylla, whereas latirostris depends on seeds from the small hard fruits of species of Hakea and Dryandra.
A mechanism for the separation of the two forms during the breeding season is suggested.
The Breeding Season of Captive Barbary Doves, Streptopelia risoria, at Helena Valley, Western Australia
Authors: Davies SJJF
Published: June 2005

The breeding season of captive barbary doves was studied near Perth, W.A., between 1966 and 1971. It was found that the birds ceased breeding in May and began again in late July. The interval from pair formation to egg-laying was long early in the breeding season, shortest in early summer, and very long in autumn.
Age Structures of Populations of Kangaroos (Macropodidae) taken by Professional Shooters in New South Wales.
Authors: Wilson GR
Published: June 2005

Skulls were aged for 4623 grey kangaroos (of both species), 1030 red kangaroos and 84 wallaroos taken by professional shooters in 1973 around eight towns in New South Wales. There was no significant difference in the proportion of adult (4-9 y) to old (10+ y) animals between areas, but there was a difference between red and grey kangaroos. The proportion of young (0-3y) animals, however, varied significantly between areas; this is attributed partly to variation between shooters.

A time-specific life table was constructed on the basis of a stationary age distribution; the annual survival was 0.661 for grey kangaroos, 0.729 for wallaroos and 0.790 for red kangaroos.

These rates seem influenced by the minimum carcass weights of 12, 13 and 16 kg for the three species respectively, and by the greater tolerance of graziers for red than grey kangaroos. The limitations and potentialities of these observations are discussed and the direction of future investigations indicated.
Reproduction in Antechinus maculatus Gould (Dasyuridae)
Authors: Aslin HJ
Published: June 2005

The smallest member of the genus Antechinus, A. maculatus has a breeding pattern unlike that of its congeners.

Captive females are polyoestrous, and can rear several litters of young each year. Both males and females show an extended breeding season in captivity, and males do not become senile after 12 months of age.

Seven litters of A. maculatus, each containing up to 11 young, have been
bred; the gestation period is 19-20 days. In comparison with most other marsupials, A. maculatus has a high reproductive potential in captivity.
The Establishment and Spread of Spilopsyllus Cuniculi (Dale) and Its Location on the Host, Oryctolagus Cuniculus (L.), In the Mallee Region of Victoria.
Authors: Shepherd RCH , Edmonds JW
Published: June 2005

European rabbit fleas (Spilopsyllus cuniculi) (Dale)) were released into a population of wild rabbits at 7 sites on Pine Plains in the Mallee district of Victoria, Australia, and their establishment and distribution observed monthly for 4 years. After 12 months, including one breeding season, the fleas were found on some rabbits up to 0.8 km from some release sites. By the end of the second breeding season, the distance of spread had doubled, and 4 years after the initial release, including 5 breeding seasons, about 95% of rabbits caught carried S. cuniculi. The furthest spread was about 13 km. When the initial release was made during the summer months, the non-breeding season, spread was slow; in one area, it took 2 years for S. cuniculi to become firmly established. When examples of S. cuniculi infected with myxoma virus were released, no establishment of the disease was observed. The numbers of S. cuniculi per rabbit were low during the first breeding season, but they were high, up to 500/rabbit, after 4 years. In most cases, the fleas were seen on the ears, pinnae and head of the rabbit and occasionally in the body fur. The highest numbers were usually found on pregnant lactating does about to litter, but some bucks also carried a large number.
The Incidence of Lead Shotgun Pellets in Waterfowl (Anatidae and Rallidae) Examined in South-Eastern Australia Between 1957 and 1973.
Authors: Norman FI
Published: June 2005

Data from the fluoroscopic examination of waterfowl (Anatidae and Rallidae) trapped at Lara, Vic., between 1957 and 1973 are summarized.

The incidence of shotgun pellets in body tissues varied between species, and within age and sex groups; generally males contained more pellets than females, and juveniles fewer than adults. Larger species tended to contain proportionally more pellets than smaller species.

Annual variations in pellet incidence were difficult to interpret, because birds examined before a shooting season contained pellets (presumably from the preceding seasons). Data from juveniles were of limited value since comparative large samples were not available after open seasons. Presence of pellets in body tissues seems to confer no disadvantage, since recovery rates, and distances travelled to recovery locations, were not significantly different for birds with or without pellets.

Examination of gizzards revealed very few ingested pellets and the data did not suggest that lead poisoning was a potential mortality factor.

It was concluded that fluoroscopic examination of waterfowl for pellet content offers little for the more effective management of the resource, since it provides, at best, post hoe information from birds whose source, and previous exposure to shooting, is generally unknown.
Extreme Risk of Mortality to Dugongs (Mammalia: Sirenia) from Netting Operations
Authors: Heinsohn GE , Marsh H , Spain AV
Published: June 2005

Successful and unsuccessful attempts at catching dugongs for research are described, including the capture of seven animals in one night near Townsville, Qld.

Aspects of handling captured animals from a small boat and the effects of net fishing on dugongs are discussed.
Numbers, Distribution and Harvesting Rate of Kangaroos on the Inland Plains of New South Wlaes
Authors: Caughley G , Sinclair RG , Wilson GR
Published: June 2005

The number of kangaroos on the plains of New South Wales (496000 km2) was estimated as 2 073 000 & 98 000 red kangaroos, Megaleia rufa, and 1 578 000 i- 84 000 grey kangaroos, Macropus giganteus and M. fuliginosus. The overall densities were 4.18 reds and 3.18 greys per square kilometre.

Sheep outnumbered kangaroos by five to one. Red kangaroos were most numerous in the north-west of the state, greys in the north-central region. The legal harvest on the survey area in 1975 was 48 100 reds and 60 300 greys, representing 2.3% of the population of reds and 3.8% of the greys.

Density is mapped for both red and grey kangaroos, and a design is offered for monitoring subsequent changes in density by aerial survey.
The glossy black-cockatoo (Calyptorhynchus lathami halmaturinus) spends little time and energy foraging on Kangaroo Island, South Australia
Authors: Chapman Tamra F. , Paton David C.
Published: June 2005

The endangered Kangaroo Island glossy black-cockatoo (Calyptorhynchus lathami halmaturinus) relies entirely on the seeds of the drooping sheoak (Allocasuarina verticillata) for food. The time budget of the glossy black-cockatoos and their foraging behaviour was recorded to provide an indication of whether their food supply was likely to be limiting. The foraging behaviour of non-breeding and breeding cockatoos was also compared to record the strategy they used to collect the additional energy needed to raise young. Glossy black-cockatoos spent a relatively small proportion of their time foraging, suggesting that the food supply was abundant in the habitats used for feeding. Non-breeding birds spent only 26% of their time feeding and breeding birds spent only 36% of their time feeding. The cockatoos spent 0.4% of their time flying, foraged in a mean of only five trees per day and harvested cones in no more than five bouts per tree. This shows that the cockatoos made few movements between drooping sheoaks and within the canopy of the sheoaks when foraging. When breeding, the cockatoos spent significantly more time per day foraging, cropped cones in significantly more bouts per tree and harvested significantly more cones per tree than non-breeding birds. This shows that breeding birds increased their energy intake without greatly increasing movement between trees. The small number of movements made by glossy black-cockatoos when foraging on Kangaroo Island reflects the abundance of food trees and may be a strategy to reduce the risk of predation.
A quasi-Monte Carlo Metropolis algorithm
Authors: Owen Art B. , Tribble Seth D.
Published: June 2005

This work presents a version of the Metropolis–Hastings algorithm using quasi-Monte Carlo inputs. We prove that the method yields consistent estimates in some problems with finite state spaces and completely uniformly distributed inputs. In some numerical examples, the proposed method is much more accurate than ordinary Metropolis–Hastings sampling.
Rapid plasticity of binocular connections in developing monkey visual cortex (V1)
Authors: Zhang Bin , Bi Hua , Sakai Eiichi , Maruko Ichiro , Zheng Jianghe , Smith Earl L. , Chino Yuzo M.
Published: June 2005

The basic sets of cortical connections are present at birth in the primate visual system. The maintenance and refinement of these innate connections are highly dependent on normal visual experience, and prolonged exposure to binocularly uncorrelated signals early in life severely disrupts the normal development of binocular functions. However, very little is known about how rapidly these changes in the functional organization of primate visual cortex emerge or what are the sequence and the nature of the abnormal neural events that occur immediately after experiencing binocular decorrelation. In this study, we investigated how brief periods of ocular misalignment (strabismus) at the height of the critical period alter the cortical circuits that support binocular vision. After only 3 days of optically imposed strabismus, there was a striking increase in the prevalence of V1 neurons that exhibited binocular suppression, i.e., binocular responses were weaker than monocular responses. However, the sensitivity of these neurons to interocular spatial phase disparity was not significantly altered. These contrasting results suggest that the first significant change in V1 caused by early binocular decorrelation is binocular suppression, and that this suppression originates at a site(s) beyond where binocular signals are initially combined.
Evasion of Toll-like receptor 5 by flagellated bacteria
Authors: Andersen-Nissen Erica , Smith Kelly D. , Strobe Katie L. , Barrett Sara L. Rassoulian , Cookson Brad T. , Logan Susan M. , Aderem Alan
Published: June 2005

Toll-like receptor 5 (TLR5) recognizes an evolutionarily conserved site on bacterial flagellin that is required for flagellar filament assembly and motility. The α and ε
Proteobacteria
, including the important human pathogens
Campylobacter jejuni
,
Helicobacter pylori
, and
Bartonella bacilliformis
, require flagellar motility to efficiently infect mammalian hosts. In this study, we demonstrate that these bacteria make flagellin molecules that are not recognized by TLR5. We map the site responsible for TLR5 evasion to amino acids 89-96 of the N-terminal D1 domain, which is centrally positioned within the previously defined TLR5 recognition site.
Salmonella
flagellin is strongly recognized by TLR5, but mutating residues 89-96 to the corresponding
H. pylori flaA
sequence abolishes TLR5 recognition and also destroys bacterial motility. To preserve bacterial motility, α and ε
Proteobacteria
possess compensatory amino acid changes in other regions of the flagellin molecule, and we engineer a mutant form of
Salmonella
flagellin that evades TLR5 but retains motility. These results suggest that TLR5 evasion is critical for the survival of this subset of bacteria at mucosal sites in animals and raise the intriguing possibility that flagellin receptors provided the selective force to drive the evolution of these unique subclasses of bacterial flagellins.
Identification of a major restriction in HIV-1 intersubtype recombination
Authors: Chin Mario P. S. , Rhodes Terence D. , Chen Jianbo , Fu William , Hu Wei-Shau
Published: June 2005

Genetic recombination increases diversity in HIV-1 populations, thereby allowing variants to escape from host immunity or antiviral therapies. In addition to the currently described nine subtypes of HIV-1, many of the circulating strains are intersubtype recombinants. In this study, we determined the recombination rate between two HIV-1 subtype C viruses and between a subtype B virus and a subtype C virus during a single round of virus replication. Although HIV-1 subtype C recombines at a high rate, similar to that of HIV-1 subtype B, the recombination rate between a subtype B virus and a subtype C virus is much lower than the intrasubtype recombination rate. A 3-nt sequence difference in the dimerization initiation signal (DIS) region between HIV-1 subtypes B and C accounts for most of the reduction of intersubtype recombination. By matching the DIS sequences, the B/C intersub-type recombination rate was elevated 4-fold; by introducing mismatches in the 3-nt sequences, the B/B intrasubtype recombination rate was reduced 4-fold. Further analyses showed that the intermolecular template-switching frequency was unaffected by the sequence identity of the DIS region. These results support the hypothesis that mismatched sequences in the DIS region alter the formation of heterozygous virions, thereby lowering the observable recombination rate. Here, we present the discovery of a major restriction in HIV-1 intersubtype recombination. These results have important implications for virus evolution, the mechanism of HIV-1 RNA packaging, high negative interference in recombination, and the generation of circulating intersubtype recombinants within the infected population.
Severe acute respiratory syndrome (SARS) S protein production in plants: Development of recombinant vaccine
Authors: Pogrebnyak Natalia , Golovkin Maxim , Andrianov Vyacheslav , Spitsin Sergei , Smirnov Yuriy , Egolf Richard , Koprowski Hilary
Published: June 2005

In view of a recent spread of severe acute respiratory syndrome (SARS), there is a high demand for production of a vaccine to prevent this disease. Recent studies indicate that SARS-coronavirus (CoV) spike protein (S protein) and its truncated fragments are considered the best candidates for generation of the recombinant vaccine. Toward the development of a safe, effective, and inexpensive vaccine candidate, we have expressed the N-terminal fragment of SARS-CoV S protein (S1) in tomato and low-nicotine tobacco plants. Incorporation of the S1 fragment into plant genomes as well as its transcription was confirmed by PCR and RT-PCR analyses. High levels of expression of recombinant S1 protein were observed in several transgenic lines by Western blot analysis using specific antibodies. Plant-derived antigen was evaluated to induce the systemic and mucosal immune responses in mice. Mice showed significantly increased levels of SARS-CoV-specific IgA after oral ingestion of tomato fruits expressing S1 protein. Sera of mice parenterally primed with tobacco-derived S1 protein revealed the presence of SARS-CoV-specific IgG as detected by Western blot and ELISA analysis.
Atomic-scale dynamical structures of fatty acid bilayers observed by ultrafast electron crystallography
Authors: Chen Songye , Seidel Marco T. , Zewail Ahmed H.
Published: June 2005

The structure and dynamics of a biological model bilayer are reported with atomic-scale resolution by using ultrafast electron crystallography. The bilayer was deposited as a Langmuir-Blodgett structure of arachidic (eicosanoic) fatty acids with the two chains containing 40 carbon atoms (≈50 Å), on a hydrophobic substrate, the hydrogen terminated silicon(111) surface. We determined the structure of the 2D assembly, establishing the orientation of the chains and the subunit cell of the CH2distances:a0= 4.7 Å,b0= 8.0 Å, andc0= 2.54 Å. For structural dynamics, the diffraction frames were taken every 1 picosecond after a femtosecond temperature jump. The observed motions, with sub-Å resolution and monolayer sensitivity, clearly indicate the coherent anisotropic expansion of the bilayer solely along the aliphatic chains, followed by nonequilibrium contraction and restructuring at longer times. This motion is indicative of a nonlinear behavior among the anharmonically coupled bonds on the ultrashort time scale and energy redistribution and diffusion on the longer time scale. The ability to observe such atomic motions of complex structures and at interfaces is a significant leap forward for the determination of macromolecular dynamical structures by using ultrafast electron crystallography.
Fetal origins of insulin resistance and obesity
Authors: Stocker Claire J. , Arch Jonathan R. S. , Cawthorne Michael A.
Published: June 2005

A number of epidemiological studies worldwide have demonstrated a relationship between poor early growth and an increased susceptibility to insulin resistance, visceral obesity, type 2 diabetes and other features of the metabolic syndrome in adulthood. However, the mechanistic basis of this relationship and the relative roles of genes and the environment remain a subject of debate. The ‘thrifty phenotype’ hypothesis proposes that poor fetal nutrition leads to programming of metabolism and an adult phenotype that is adapted to poor but not plentiful nutrition. The maternal reduced-protein rat model has been used to examine the importance of the maternal environment in determining susceptibility to adult disease. Pregnant and lactating rat dams are fed a diet containing 80 g protein/kg as compared with 200 g protein/kg, which leads to growth restriction in utero. Offspring of low-protein dams have increased susceptibility to diabetes, insulin resistance and hypertension when fed a palatable high-fat diet that promotes obesity. Administration of leptin during pregnancy and lactation to these protein-restricted dams produces offspring that have increased metabolic rate and do not become obese or insulin resistant when fed on a high-fat diet. Increased glucocorticoid exposure, particularly during late gestation, has been linked with insulin resistance in adulthood. High levels of fetal glucocorticoids may result from a decreased activity of placental 11β-hydroxysteroid dehydrogenase (11β-HSD) type 2, which normally protects the fetus from high maternal glucocorticoid levels. Leptin administration to protein-restricted dams inhibits the suppression of 11β-HSD-2 and may be one mechanism by which the metabolic syndrome is prevented.
Shifts in targeting of class switch recombination sites in mice that lack μ switch region tandem repeats or Msh2
Authors: Min Irene M. , Rothlein Lisa R. , Schrader Carol E. , Stavnezer Janet , Selsing Erik
Published: June 2005

The mechanisms that target class switch recombination (CSR) to antibody gene switch (S) regions are unknown. Analyses of switch site locations in wild-type mice and in mice that lack the Sμ tandem repeats show shifts indicating that a 4–5-kb DNA domain (bounded upstream by the Iμ promoter) is accessible for switching independent of Sμ sequences. This CSR-accessible domain is reminiscent of the promoter-defined domains that target somatic hypermutation. Within the 4–5-kb CSR domain, the targeting of S site locations also depends on the Msh2 mismatch repair protein because Msh2-deficient mice show an increased focus of sites to the Sμ tandem repeat region. We propose that Msh2 affects S site location because sequences with few activation-induced cytidine deaminase targets generate mostly switch DNA cleavages that require Msh2-directed processing to allow CSR joining.
Identification of eosinophil lineage–committed progenitors in the murine bone marrow
Authors: Iwasaki Hiromi , Mizuno Shin-ichi , Mayfield Robin , Shigematsu Hirokazu , Arinobu Yojiro , Seed Brian , Gurish Michael F. , Takatsu Kiyoshi , Akashi Koichi
Published: June 2005

Eosinophil lineage–committed progenitors (EoPs) are phenotypically isolatable in the steady-state murine bone marrow. Purified granulocyte/monocyte progenitors (GMPs) gave rise to eosinophils as well as neutrophils and monocytes at the single cell level. Within the short-term culture of GMPs, the eosinophil potential was found exclusively in cells activating the transgenic reporter for GATA-1, a transcription factor capable of instructing eosinophil lineage commitment. These GATA-1–activating cells possessed an IL-5Rα+CD34+c-Kitlo phenotype. Normal bone marrow cells also contained IL-5Rα+CD34+c-Kitlo EoPs that gave rise exclusively to eosinophils. EoPs significantly increased in number in response to helminth infection, suggesting that the EoP stage is physiologically involved in eosinophil production in vivo. EoPs expressed eosinophil-related genes, such as the eosinophil peroxidase and the major basic protein, but did not express basophil/mast cell–related mast cell proteases. The enforced retroviral expression of IL-5Rα in GMPs did not enhance the frequency of eosinophil lineage read-outs, whereas IL-5Rα+ GMPs displayed normal neutrophil/monocyte differentiation in the presence of IL-5 alone. Thus, IL-5Rα might be expressed specifically at the EoP stage as a result of commitment into the eosinophil lineage. The newly identified EoPs could be the cellular target in the treatment of a variety of disorders mediated by eosinophils.
The Tarantula Toxin Psalmotoxin 1 Inhibits Acid-sensing Ion Channel (ASIC) 1a by Increasing Its Apparent H+ Affinity
Authors: Chen Xuanmao , Kalbacher Hubert , Gründer Stefan
Published: June 2005

Acid-sensing ion channels (ASICs) are ion channels activated by extracellular protons. They are involved in higher brain functions and perception of pain, taste, and mechanical stimuli. Homomeric ASIC1a is potently inhibited by the tarantula toxin psalmotoxin 1. The mechanism of this inhibition is unknown. Here we show that psalmotoxin 1 inhibits ASIC1a by a unique mechanism: the toxin increases the apparent affinity for H+ of ASIC1a. Since ASIC1a is activated by H+ concentrations that are only slightly larger than the resting H+ concentration, this increase in H+ affinity is sufficient to shift ASIC1a channels into the desensitized state. As activation of ASIC1a has recently been linked to neurodegeneration associated with stroke, our results suggest chronic desensitization of ASIC1a by a slight increase of its H+ affinity as a possible way of therapeutic intervention in stroke.
HEGESMA: genome search meta-analysis and heterogeneity testing
Authors: Zintzaras Elias , Ioannidis John P. A.
Published: June 2005

Summary: Heterogeneity and genome search meta-analysis (HEGESMA) is a comprehensive software for performing genome scan meta-analysis, a quantitative method to identify genetic regions (bins) with consistently increased linkage score across multiple genome scans, and for testing the heterogeneity of the results of each bin across scans. The program provides as an output the average of ranks and three heterogeneity statistics, as well as corresponding significance levels. Statistical inferences are based on Monte Carlo permutation tests. The program allows both unweighted and weighted analysis, with the weights for each study as specified by the user. Furthermore, the program performs heterogeneity analyses restricted to the bins with similar average ranks.

Availability:  http://biomath.med.uth.gr

Contact:  zintza@med.uth.gr
THE ROLE OF EXPECTATIONS IN ADOLESCENT SCHOOLING CHOICES: DO YOUTHS RESPOND TO ECONOMIC INCENTIVES?
Authors: WILSON KATHRYN , WOLFE BARBARA , HAVEMAN ROBERT
Published: June 2005

We address the role of youths' own choice‐conditioned expectations in understanding their schooling choices by constructing a choice (or “switching”) model. We emphasize the effect of individual student perceptions regarding the returns associated with graduating from high school versus dropping out, while controlling for an extensive set of family and community factors. We find that youths' expected income returns to graduating from high school are influential in their schooling choices, even when an extensive set of background, economic, family, and neighborhood variables, designed to capture the effects of parental and governmental decisions, is introduced into the analysis. (JEL I20, J24)
WELFARE AND PUBLIC POLICY: THE ROLE OF INTERNATIONALIZED PRODUCTION
Authors: CHU HSIAO‐LEI
Published: June 2005

I incorporate internationalized production, whereby firms hire domestic and foreign production factors, into the model of Corsetti and Pesenti (2001). In contrast to their conclusion, I find that an expansionary monetary shock can be beggar‐thy‐neighbor and a fiscal shock can improve national welfare. The transmission mechanism of public policy here is different from theirs. In particular, a fiscal shock can affect the short‐run exchange rate and generate long‐run welfare effects even if it is temporary. Results in this article offer another rationale for international retaliation and coordination. (JEL F30, F40)
ORGANIZED CRIME OR INDIVIDUAL CRIME? ENDOGENOUS SIZE OF A CRIMINAL ORGANIZATION AND THE OPTIMAL LAW ENFORCEMENT
Authors: CHANG JUIN‐JEN , LU HUEI‐CHUNG , CHEN MINGSHEN
Published: June 2005

This article develops a simple but general criminal decision framework in which individual crime and organized crime are coexisting alternatives to a potential offender. It enables us to endogenize the size of a criminal organization and explore interactive relationships among sizes of criminal organization, the crime rate, and the government's law enforcement strategies. We show that the method adopted to allocate the criminal organization's payoffs and the extra benefit provided by the criminal organization play crucial roles in an individual's decision to commit a crime and the way in which he or she commits that crime. The two factors also jointly determine the market structure for crime and the optimal law enforcement strategy to be adopted by a government. (JEL K4)
DO DRAGONS HAVE BETTER FATE?
Authors: WONG KA‐FU , YUNG LINDA
Published: June 2005

Traditionally, belief in the Chinese zodiac promotes the superstition that the timing of one's birth determines one's fate. Adherence to this belief has resulted in increased birth rates during Dragon years and, hence, problems in the logistics of providing certain public goods and services (such as schools and medical services) by governments. Despite the possible economic impacts of this superstition on society, no previous study has attempted to test its validity. Using the 1991 and 1996 Hong Kong census data sets, as well as the standard return‐to‐education methodology, we do not find any evidence for this pervasive superstition. (JEL J13, J18, Z12)
The performance of habit in Montaigne's ‘De mesnager sa volonté’
Authors: Butterworth Emily
Published: June 2005

This article focuses on the concepts of habit and performance and how they relate to concepts of subjectivity in Montaigne's ‘De mesnager sa volonté’. Montaigne's chapter considers action on the political stage and contrasts two models for political action: impassioned activity and moderate engagement. I look at how Montaigne modulates his argument through Seneca and how metaphor is used to describe the ideal of interior integrity, a space for the self protected from the ‘outside’. This is then undercut by a temporal model of the self, informed by the Stoic notion of public life as a theatrical role and by scholastic concepts of custom and the habitus. For Montaigne, custom or habit supplements nature and renders our relationship to the natural problematic. I argue that in this chapter the self appears as a palimpsest, built up and consolidated over time. In this way each role or act could be considered performative in that they construct and constitute the individual. Finally, I argue that for Montaigne, the writing of the
Essais
is also performative, and that his ‘bonne foy’ is a fidelity to passage and becoming.
Meat, murder, metamorphosis the transformational ethics of François Ozon
Authors: Asibong Andrew
Published: June 2005

This article argues that French filmmaker François Ozon's fantastical explorations of murder and metamorphosis provide a surprisingly ethical commentary on the tightly interwoven cultural processes of social reification and identity fetishization. Using the two early films
Sitcom
(1998) and
Les Amants criminels
(1999) as a point of departure, it claims that Ozon is essentially concerned with the different ways in which the subject appropriates alterity in his or her attempt to instigate alternative existences. Using the theories of Deleuze and Guattari on ‘deterritorialization’, those of Slavoj Žižek on ‘the Act’, and those of Giorgio Agamben on ‘the witness’, it will present three distinct stages of transformation at work in Ozon's films: from a seeming championing of transgressive social ‘difference’ for its own sake emerges an exploration of impossible, psychotic metamorphosis, and finally a linking of such ‘unspeakable’ change to a potentially political process of traumatic dehumanization. Real, that is, ethical, transformation in Ozon's films can come about only through the blinding perception of one's enslavement to fetishistic desire, and through the radical dismantlement of this desire and the (excessively) coherent socio-political identity it confers upon one. Ozon's demanding approach to different modes of transformation deserves close analysis at a time when increasingly rigid conceptions of social identity are again becoming dangerously allied to lazy conceptions of social change, in France and elsewhere.
Embedding formulae for diffraction by rational wedge and angular geometries
Authors: Craster R.V , Shanin A.V
Published: June 2005

Embedding is the process of taking the far-field directivity from a diffraction problem (or problems) involving line sources or multipoles placed at a sharp edge, and then constructing the far field, for the same geometry, for more general incidence using only this canonical problem(s). Thus far, embedding has been limited to planar, parallel scattering surfaces, for instance, collections of parallel cracks or slits; it appeared that there was a fundamental limitation to embedding, disallowing its use for angular structures. In this article, we overcome this limitation and demonstrate the use of embedding upon wedge diffraction problems and upon a simple polygonal shape; a limitation is that the final formulae are for rational wedge angles.
Impact of UV-B exposure on amphibian embryos: linking species physiology and oviposition behaviour
Authors: Palen Wendy J , Williamson Craig E , Clauser Aaron A , Schindler Daniel E
Published: June 2005

Increasing ultraviolet-B radiation (UV-B) has recently captured the attention of ecologists as a key environmental stressor. Certain species may be particularly vulnerable as a result of either high natural exposure to UV-B or limited physiological capacity to withstand it. UV-B sensitivity has been examined at the cellular and individual level for a wide variety of taxa, but estimates of exposure to UV-B in natural systems are lacking and predictions of large-scale impacts are therefore limited. Here, we combine data on the physiological sensitivity to UV-B and patterns of field exposure across sites for embryos of several well-studied US Pacific Northwest amphibian species. We find substantial differences among species' physiological abilities to withstand UV-B and in the level of UV-B exposure of embryos in the field. More specifically, we find that species with the highest physiological sensitivity to UV-B are those with the lowest field exposures as a function of the location of embryos and the UV-B attenuation properties of water at each site. These results also suggest that conclusions made about species' vulnerability to UV-B in the absence of information on field exposures may often be misleading.
Effects of early experience on female behavioural and reproductive development in rhesus macaques
Authors: Maestripieri Dario
Published: June 2005

A growing body of research on humans suggests that exposure to a stressful family environment or father absence from home during childhood is associated with early female puberty and greater interest in infants among adolescent girls. This effect may be mediated by early exposure to harsh and inconsistent maternal care, but the mechanisms by which maternal care affects female reproductive maturation are not known. The present study reports sex differences in interest in infants among juvenile rhesus macaques similar to those observed in human adolescents. Furthermore, juvenile females that were exposed to harsh and inconsistent maternal care in infancy showed higher interest in infants than controls. Evidence from cross-fostered females indicated that these effects resulted from early experience and not genetic inheritance from the mother. There were no significant differences in female age at first conception in relation to the quality of maternal care received during infancy. Macaque females exposed to harsh and inconsistent maternal care in infancy tended to have higher cortisol responses to stress and to corticotropin-releasing hormone than controls in the first three years of life. Furthermore, females with higher cortisol responses to stress exhibited higher interest in infants. These findings suggest that some of the effects of early parental care on female reproductive maturation may be mediated by developmental changes in the activity of the hypothalamic–pituitary–adrenal axis.
Habitat structure and the dispersal of male and female bottlenose dolphins (Tursiops truncatus)
Authors: Natoli Ada , Birkun Alexei , Aguilar Alex , Lopez Alfredo , Hoelzel A. Rus
Published: June 2005

Bottlenose dolphins (Tursiops truncatus) are widely distributed and a high degree of morphometric and genetic differentiation has been found among both allopatric and parapatric populations. We analysed 145 samples along a contiguous distributional range from the Black Sea to the eastern North Atlantic for mitochondrial and nuclear genetic diversity, and found population structure with boundaries that coincided with transitions between habitat regions. These regions can be characterized by ocean floor topography, and oceanographic features such as surface salinity, productivity and temperature. At the extremes of this range there was evidence for the directional emigration of females. Bi-parentally inherited markers did not show this directional bias in migration, suggesting a different dispersal strategy for males and females at range margins. However, comparative assessment based on mitochondrial DNA and nuclear markers indicated that neither sex showed a strong bias for greater dispersal on average. These data imply a mechanism for the evolutionary structuring of populations based on local habitat dependence for both males and females.