bluuebunny/crossref_metadata_2025 huggingface dataset:
Diffuse attenuation coefficient of downwelling irradiance: An evaluation of remote sensing methods
Authors: Lee Zhong‐Ping , Darecki Miroslaw , Carder Kendall L. , Davis Curtiss O. , Stramski Dariusz , Rhea W. Joseph
Published: February 2005

The propagation of downwelling irradiance at wavelength λ from surface to a depth (z) in the ocean is governed by the diffuse attenuation coefficient, (λ). There are two standard methods for the derivation of (λ) in remote sensing, which both are based on empirical relationships involving the blue‐to‐green ratio of ocean color. Recently, a semianalytical method to derive (λ) from reflectance has also been developed. In this study, using (490) and (443) as examples, we compare the (λ) values derived from the three methods using data collected in three different regions that cover oceanic and coastal waters, with (490) ranging from ∼0.04 to 4.0 m−1. The derived values are compared with the data calculated from in situ measurements of the vertical profiles of downwelling irradiance. The comparisons show that the two standard methods produced satisfactory estimates of (λ) in oceanic waters where attenuation is relatively low but resulted in significant errors in coastal waters. The newly developed semianalytical method appears to have no such limitation as it performed well for both oceanic and coastal waters. For all data in this study the average of absolute percentage difference between the in situ measured and the semianalytically derived is ∼14% for λ = 490 nm and ∼11% for λ = 443 nm.
Bed form initiation from a flat sand bed
Authors: Venditti Jeremy G. , Church Michael A. , Bennett Sean J.
Published: February 2005

Bed form initiation in unidirectional flow is examined on a flat bed composed of a homogeneous 0.5 mm sand. Velocity profiles taken prior to bed form development indicate that the examined flows are typical of fully turbulent, uniform, open channel flows. Under these conditions, two separate modes of bed form initiation are observed: defect and instantaneous initiation. Defect initiation occurs at lower flow stages, where sediment transport is sporadic and patchy, and is characterized by defect propagation associated with flow separation. Instantaneous initiation occurs at larger flow strengths, where sediment transport is general and widespread. This form of bed form initiation begins with the imprinting of a cross‐hatch pattern on the flat sediment bed, which leads to chevron‐shaped forms that migrate independently of the initial pattern. The chevrons eventually align to form incipient crest lines. This mode of bed form initiation does not appear to be linked to turbulent structures, but integral scales derived from velocity measurements prior to bed form development are similar to the initial bed form length scales.
Fresh and saline groundwater discharge to the ocean: A regional perspective
Authors: Wilson Alicia M.
Published: February 2005

Studies of groundwater flow in coastal aquifers often focus strongly on freshwater and investigate flow in a narrow (<5 km) zone surrounding the coastline. This work was designed to place coastal flow in a regional context and to compare fresh and saline submarine groundwater discharge (SGD) for regional flow systems. Numerical flow and transport models were developed to estimate SGD associated with topography‐driven flow, seawater recirculation, and geothermal convection in a passive margin setting. Simulations were based on two cross sections of North Carolina, and sensitivity studies were used to explore the impact of varying hydraulic and transport parameters. Results suggest that saline flow associated with seawater recirculation and geothermal convection should be considered in studies of SGD. Studies limited to shallow topography‐driven flow may be justified in using small study areas, but flow systems contributing to SGD may span at least 20 km surrounding the coast and continental slope.
Mefenamic acid as a novel activator of L‐type voltage‐dependent Ca2+ channels in smooth muscle cells from pig proximal urethra
Authors: Teramoto Noriyoshi , Tomoda Toshihisa , Ito Yushi
Published: February 2005

The effects of mefenamic acid and Bay K 8644 on voltage‐dependent nifedipine‐sensitive inward Ba2+ currents in pig urethral myocytes were investigated by use of conventional whole‐cell configuration patch clamp.

Mefenamic acid increased the peak amplitude of voltage‐dependent nifedipine‐sensitive inward Ba2+ current without shifting the position of the current–voltage relationship.

Mefenamic acid (300 μM) caused little shift in the activation curve although the voltage dependence of the steady‐state inactivation was shifted to more positive potentials by 11 mV in the presence of mefenamic acid.

Bay K 8644 (100 nM) enhanced voltage‐dependent nifedipine‐sensitive inward Ba2+ currents in a concentration‐ and voltage‐dependent manner, shifting the maximum of the current–voltage relationship by 10 mV in the hyperpolarizing direction.

Bay K 8644 (1 μM) significantly shifted the voltage dependence of the activation curve to more negative potentials by approximately 9 mV although Bay K 8644 caused little shift in the steady‐state inactivation curve.

These results indicate that mefenamic acid increased voltage‐dependent nifedipine‐sensitive inward Ba2+ currents through the activation of L‐type Ca2+ channels with different kinetics from those of Bay K 8644 in pig urethral myocytes.

British Journal of Pharmacology (2005) 144, 919–925. doi:10.1038/sj.bjp.0706051
Muscarinic receptor subtypes in human bladder detrusor and mucosa, studied by radioligand binding and quantitative competitive RT–PCR: changes in ageing
Authors: Mansfield Kylie J , Liu Lu , Mitchelson Frederick J , Moore Kate H , Millard Richard J , Burcher Elizabeth
Published: February 2005

We investigated muscarinic receptors in the detrusor and mucosa of the human bladder body. Radioligand‐binding studies with [3H]QNB were conducted using specimens collected from patients (36–77 years) with normal bladder function, undergoing surgery. For RT–PCR, biopsies of normal bladder were obtained from patients (30–88 years) undergoing check cystoscopy.

Binding of [3H]QNB in detrusor (n=20) was of high affinity (KD 77.1 (55.2–99.0) pM) and capacity (Bmax 181±7 fmol mg protein−1). Similar values were obtained in mucosa (n=6) (KD 100.5 (41.2–159.9) pM; Bmax 145±9 fmol mg protein−1).

Competition‐binding experiments in detrusor membranes with muscarinic receptor antagonists including trospium, darifenacin, 4‐DAMP, methoctramine, AQ‐RA 741, AF‐DX 116 and pirenzepine indicated a receptor population of 71% M2, 22% M3 and 7% M1. In the mucosa, 75% of sites were M2 receptors, with 25% M3/M5.

Using RT–PCR, expression of M1, M2, M3 and M5 mRNA was demonstrated in both detrusor and mucosa.

The presence of a high density of mainly M2 muscarinic receptors in the mucosa appears to be a novel finding and raises the question of their physiological significance and the source of their endogenous ligand.

There was a negative correlation of receptor number (Bmax) with age in detrusor muscle from male patients (P=0.02). Quantitative competitive RT–PCR demonstrated a selective age‐related decrease in mRNA for muscarinic M3 but not M2 receptors, in both male (P<0.0001) and female (P=0.019) detrusor. These findings correspond with reports of decreased detrusor contractility with ageing.

British Journal of Pharmacology (2005) 144, 1089–1099. doi:10.1038/sj.bjp.0706147
Hyperforin activates nonselective cation channels (NSCCs)
Authors: Treiber Kristina , Singer Andrea , Henke Bettina , Müller Walter E
Published: February 2005

A large body of evidence supports the preclinical antidepressant profile of hyperforin including inhibition of the synaptosomal uptake of several neurotransmitters by hyperforin and studies in behavioural models. In contrast to other antidepressants, hyperforin does not directly inhibit neurotransmitter transporters, but instead uptake inhibition seems to be the consequence of an elevated intracellular sodium concentration ([Na+]i).

The mechanism of hyperforin‐induced elevation of [Na+]i was investigated using two different cell types: human platelets and rat pheochromocytoma cells (PC12 cells). In both cell systems, hyperforin increased both [Na+]i and free intracellular Ca2+ concentration ([Ca2+]i).

One pathway for Na+ and Ca2+ entry is mediated by nonselective cation channels (NSCCs), which can be blocked by SK&F 96365 and LOE 908. LOE 908 is a blocker of both NSCC1 and NSCC2 subclasses, while SK&F 96365 blocks NSCC2 only. Both SK&F 96365 and LOE 908 completely inhibited the hyperforin‐induced influx of Na+ and Ca2+ into platelets and PC12 cells. This indicates that hyperforin is mainly active upon NSCC2.

The effect of hyperforin is inhibited by La3+ and Gd3+, indicating that there is a potential homology with canonical transient receptor potential protein channels (TRPC channels). Moreover, La3+ and Gd3+ attenuate the effect of hyperforin on serotonin uptake in human platelets. Additionally, hyperforin induces barium influx in PC12 cells and this influx can be inhibited by SK&F 96365, LOE 908, Gd3+ and La3+.

In summary, these findings suggest that hyperforin represents a new principle for preclinical antidepressant activity, modulating brain neurotransmission by inhibition of neurotransmitter uptake via activation of NSCCs.

British Journal of Pharmacology (2005) 145, 75–83. doi:10.1038/sj.bjp.0706155
Signaling of short‐ and long‐term regulation of intestinal epithelial type 1 Na+/H+ exchanger by interferon‐γ
Authors: Magro Fernando , Fraga Sónia , Soares‐da‐Silva Patrício
Published: February 2005

The present study evaluated the effect of interferon‐γ (IFN‐γ) on intestinal Na+/H+ exchange (NHE) activity and the intracellular signaling pathways set into motion after IFN‐γ receptor activation.

Caco‐2 cells express endogenous NHE1, NHE2 and NHE3 proteins, as detected by immunoblotting. Short‐ (0.5 h) and long‐ (24 h) term exposure of Caco‐2 cells to IFN‐γ resulted in a concentration‐dependent decrease in NHE activity. Inhibition of NHE activity by IFN‐γ was absent in cariporide‐treated cells, but not in cells treated with S‐3226. The long‐term exposure to IFN‐γ was accompanied by a 20% increase in surface NHE1 abundance and no changes in total NHE1 abundance.

Inhibition of Raf1, mitogen‐activated protein kinase kinase (MAPKK/MEK) and p38 MAPK with, respectively, GW 5074, PD 98059 and SB 203580 and downregulation of protein kinase C (PKC) with phorbol‐12,13‐dibutyrate (100 nM for 24 h) prevented inhibition of NHE activity by IFN‐γ (0.5 and 24 h exposure). The signal transducer and activator transcription factor 1 (STAT1) inhibitor epigallocatechin‐3‐gallate (EGCG) prevented inhibition of NHE activity by long‐ but not the short‐term treatment with IFN‐γ.

Treatment with IFN‐γ activated phospho‐p38 MAPK, this effect being detected as early as 1 h, persisting over 3 h and decreasing after 24 h. IFN‐γ produced a sustained action of phospho‐STAT1 that was prevented by EGCG and partially attenuated by SB 203580 and insensitive to downregulation of PKC.

In conclusion, short‐ and long‐term inhibition of NHE1 activity by IFN‐γ involves a complex signaling pathway that includes PKC activation and STAT1 phosphorylation, respectively, but is not accompanied by downregulation of NHE1.

British Journal of Pharmacology (2005) 145, 93–103. doi:10.1038/sj.bjp.0706167
Using nuclear data and Monte Carlo techniques to study areal density and mix in D2 implosions
Authors: Kurebayashi S. , Frenje J. A. , Séguin F. H. , Rygg J. R. , Li C. K. , Petrasso R. D. , Glebov V. Yu. , Delettrez J. A. , Sangster T. C. , Meyerhofer D. D. , Stoeckl C. , Soures J. M. , Amendt P. A. , Hatchett S. P. , Turner R. E.
Published: February 2005

Measurements from three classes of direct-drive implosions at the OMEGA laser system [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] were combined with Monte Carlo simulations to investigate models for determining hot-fuel areal density (ρRhot) in compressed, D2-filled capsules, and to assess the impact of mix and other factors on the determination of ρRhot. The results of the Monte Carlo simulations were compared to predictions of simple, commonly used models that use ratios of either secondary D3He proton yields or secondary DT neutron yields to primary DD neutron yields to provide estimates ρRhot,2p or ρRhot,2n, respectively, for ρRhot. For the first class of implosion, where ρRhot is low (⩽3 mg/cm2), ρRhot,2p and ρRhot,2n often agree with each other and are often good estimates of the actual ρRhot. For the second class of implosion, where ρRhot is of order 10 mg/cm2, ρRhot,2p often underestimates the actual value due to secondary proton yield saturation; in addition, fuel-shell mix causes ρRhot,2p to further underestimate, and ρRhot,2n to overestimate, ρRhot. As a result, values of ρRhot,2p and ρRhot,2n can be interpreted as lower and upper limits, respectively. For the third class of implosion, involving cryogenic capsules, secondary protons and neutrons are produced mainly in the hot and cold fuel regions, respectively, and the effects of the mixing of hot and cold fuel must be taken into account when interpreting the values of ρRhot,2p and ρRhot,2n. From these data sets, it is concluded that accurate inference of ρRhot requires comprehensive measurements and detailed modeling.
Upper limit on the critical strength of central potentials in relativistic quantum mechanics
Authors: Brau Fabian
Published: February 2005

In the context of relativistic quantum mechanics, where the Schrödinger equation is replaced by the spinless Salpeter equation, we show how to construct a large class of upper limits on the critical value, gc(l), of the coupling constant, g, of the central potential, V(r)=−gv(r). This critical value is the value of g for which a first l-wave bound state appears.
Use of the 4∕5 Kolmogorov equation for describing some characteristics of fully developed turbulence
Authors: Tatarskii V. I.
Published: February 2005

The Kolmogorov equation, which relates the second-order structure function Dll(r) and the third-ordrer structure function Dlll(r), may be presented as a closed linear integrodifferential equation for the probability distribution function W(U,r) of longitudinal velocity difference U. In general, without any restrictions, the function of two variables W(U,r) may be presented as [Dll(r)]−1∕2F(U∕Dll(r),r). As a first approximation, we neglect dependence of F on the second argument r. In this approximation (self-similarity of the probability density function), the integrodifferential equation for W reduces to the ordinary nonlinear differential equation for Dll(r). It follows from this equation that for r→∞ the function Dll(r)∼r2∕3. This consideration does not use the 1941 Kolmogorov hypothesis that is based on dimension analysis. Any deviations from the 2∕3 law, including intermittency effects, must be related to the violation of the above-mentioned self-similarity of W, i.e., with the additional dependence of F on the second argument r. On the basis of experimental data, we suggest a simple model of W, which allows us to describe deviations from the 2∕3 law, caused by intermittency, and describe the local exponents κ in the structure functions ⟨∣U(r)∣ρ⟩∼rκ(ρ) for moderate ρ. The so called “bottleneck effect” also can be described by 4∕5 Kolmogorov equation.
Enhanced damping of capillary bridge oscillations using velocity feedback
Authors: Wei Wei , Thiessen David B. , Marston Philip L.
Published: February 2005

In reduced gravity, the stability of cylindrical liquid bridges and other systems having free surfaces is affected by ambient vibrations of the spacecraft. Such vibrations are expected to excite capillary modes. The lowest-order unstable mode of a liquid bridge is particularly susceptible to vibration as the length of the bridge approaches the stability limit. This mode is known as the (2,0) mode and is an axisymmetric varicose mode of one wavelength in the axial direction. In this work, an optical system is used to detect the (2,0)-mode amplitude. The derivative of the error signal produced by this detector is used to produce the appropriate voltages on a pair of annular disk electrodes which are concentric with the bridge. A mode-coupled Maxwell stress profile is thus generated in proportion to the modal velocity. Depending on the sign of the gain, the damping of the capillary oscillation can be either increased or decreased. This effect has been demonstrated in Plateau-tank experiments. Increasing the damping of the capillary modes on free liquid surfaces in space could be beneficial for containerless processing and other technologies.
Mechanically driven phase separation and corresponding microhardness change in Cu60Zr20Ti20 bulk metallic glass
Authors: Cao Qingping , Li Jinfi , Zhou Yaohe , Jiang Jianzhong
Published: February 2005

Rolling deformation of bulk Cu60Zr20Ti20 metallic glass has been performed at cryogenic temperature. The specimens exhibit excellent ductility, and are rolled up to 97% reduction in thickness without fracture. Crystallization is suppressed during the deformation, however, phase separation is observed in the glassy matrix when the thickness reduction exceeds 89%. Once the phase separation occurs, the microhardness of the specimen increases drastically, indicating the existence of work hardening by severe plastic deformation of the metallic glass.
Organic field-effect transistors with single and double pentacene layers
Authors: Jung Suyong , Yao Zhen
Published: February 2005

We report the characterization of field-effect transistors fabricated within individual grains of single and double pentacene layers grown on silicon oxide. Field-effect mobilities are found to increase with increasing gate voltage and exhibit a thermally activated form for the temperature dependence. These characteristics can be explained by the multiple trapping and release model. The mobilities of double-layer devices are one order of magnitude higher than those of single-layer devices. Possible origins of the traps are discussed. The geometry of these ultrathin devices makes them suitable for sensing applications.
Fabrication of a nanoelectromechanical switch using a suspended carbon nanotube
Authors: Cha S. N. , Jang J. E. , Choi Y. , Amaratunga G. A. J. , Kang D.-J. , Hasko D. G. , Jung J. E. , Kim J. M.
Published: February 2005

Fabrication and characterization of a nanoelectromechanical switching device consisting of a suspended multiwalled carbon nanotube and self-aligned electrodes is reported. The device has a triode structure and is designed so that a suspended carbon nanotube is mechanically switched to one of two self-aligned electrodes by repulsive electrostatic forces between the nanotube and the other self-aligned electrode. Carbon nanotubes are dispersed on an SiO2 coated Si wafer and their locations recorded using a scanning electron microscope mapping process. Contact electrodes and self-aligned deflection electrodes are formed by a process comprising electron beam lithography, metallic thin film deposition, and lift-off. The electrical measurements show well-defined ON and OFF states with change of gate voltage. The measured threshold voltage for electromechanical switching is ∼3.6V.
Low temperature internal friction in nanocrystalline diamond films
Authors: Metcalf Thomas H. , Liu Xiao , Houston Brian H. , Baldwin Jeffrey W. , Butler James E. , Feygelson Tatyana
Published: February 2005

Measurements of the temperature dependence of the internal friction and frequency of three nanocrystalline diamond films grown on silicon oscillator substrates indicate that the mechanical properties of the films are dominated by their interface layers. The films, with thicknesses of 0.3, 0.6, and 1.14μm, were measured between 0.4K and room temperature and have low temperature (below 10K) internal frictions between 2×10−6 and 5×10−6, which is an order of magnitude lower than has been reported previously. Additionally, all films display an internal friction peak at approximately 1.7K. The shear modulus of the films, 545–551GPa, is comparable to that for single-crystal diamond.
Determination of electron escape depth in ultrathin silicon oxide
Authors: Nohira H. , Okamoto H. , Azuma K. , Nakata Y. , Ikenaga E. , Kobayashi K. , Takata Y. , Shin S. , Hattori T.
Published: February 2005

Using the high-brilliance synchrotron radiation at SPring-8, we determined the electron escape depths in approximately 1-nm-thick low-temperature oxide layers, which were formed on Si(100) at 300°C using three kinds of atomic oxygen and that in approximately 1-nm-thick thermally grown oxide layer formed in 1Torr dry oxygen at 900°C by measuring angle-resolved Si2p photoelectron spectra at the photon energy of 1050eV. The results indicated that the electron escape depths in the three kinds of low-temperature oxide layers were 18%–24% smaller than that in the thermally grown oxide layer. Furthermore, the electron escape depth in the thermally grown oxide layer, whose thickness was close to that of the structural transition layer, was 7% smaller than that in bulk SiO2.
Magnetocapacitance and exponential magnetoresistance in manganite–titanate heterojunctions
Authors: Nakagawa N. , Asai M. , Mukunoki Y. , Susaki T. , Hwang H. Y.
Published: February 2005

We present a rectifying manganite–titanate heterojunction exhibiting a magnetic field tunable depletion layer. This creates a large positive magnetocapacitance, a direct measure of the field-induced reduction of the effective depletion width across the junction. Furthermore, the reduction of the junction barrier shifts the forward bias characteristics, giving exponentially enhanced differential magnetoresistance, occurring despite the absence of a spin filter. These results provide a unique probe of a Mott insulator∕band insulator interface, and further suggest electronic devices incorporating the magnetic field sensitivity of these strongly correlated electron materials.
Influence of some external factors on the rooting of GF677, peach and nectarine shoot hardwood cuttings
Authors: Tsipouridis C. , Thomidis T. , Michailides Z.
Published: February 2005

The influence of some external factors [cultivar, indole-butyric acid (IBA) concentration, IBA dipping of shoot tip and base, preheating of cuttings, collecting date, time of cutting collection, mother tree age, cultivar, length of and diameter of cutting] on rooting of peach–nectarine hardwood shoots in the field were examined. It was found that the best IBA concentration for rooting differed among peach cultivars. Rooting of cuttings whose bases only were immersed in IBA solution was higher than those that had both base and tip immersed. In addition, a higher percentage of rooting shoots was achieved with preheating of cuttings before planting. The best length for cuttings varied between cultivars and the best diameter was 10–13 mm. Cuttings collected between 25 October and 13 November (1997 and 1998) showed the highest percentage of rooting shoots. There was also a higher percentage of rooting GF677 hardwood shoot cuttings collected from 7-year-old mother trees compared with those collected from 1-year-old mother trees.
A survey of management and economic impact of weeds in dryland cotton cropping systems of subtropical Australia
Authors: Walker S. R. , Taylor I. N. , Milne G. , Osten V. A. , Hoque Z. , Farquharson R. J.
Published: February 2005

In dryland cotton cropping systems, the main weeds and effectiveness of management practices were identified, and the economic impact of weeds was estimated using information collected in a postal and a field survey of Southern Queensland and northern New South Wales. Forty-eight completed questionnaires were returned, and 32 paddocks were monitored in early and late summer for weed species and density. The main problem weeds were bladder ketmia (Hibiscus trionum), common sowthistle (Sonchus oleraceus), barnyard grasses (Echinochloa spp.), liverseed grass (Urochloa panicoides) and black bindweed (Fallopia convolvulus), but the relative importance of these differed with crops, fallows and crop rotations. The weed flora was diverse with 54 genera identified in the field survey. Control of weed growth in rotational crops and fallows depended largely on herbicides, particularly glyphosate in fallow and atrazine in sorghum, although effective control was not consistently achieved. Weed control in dryland cotton involved numerous combinations of selective herbicides, several non-selective herbicides, inter-row cultivation and some manual chipping. Despite this, residual weeds were found at 38–59% of initial densities in about 3-quarters of the survey paddocks. The on-farm financial costs of weeds ranged from $148 to 224/ha.year depending on the rotation, resulting in an estimated annual economic cost of $19.6 million. The approach of managing weed populations across the whole cropping system needs wider adoption to reduce the weed pressure in dryland cotton and the economic impact of weeds in the long term. Strategies that optimise herbicide performance and minimise return of weed seed to the soil are needed. Data from the surveys provide direction for research to improve weed management in this cropping system. The economic framework provides a valuable measure of evaluating likely future returns from technologies or weed management improvements.
Effects of a novel ryegrass endophyte on pasture production, dairy cow milk production and calf liveweight gain
Authors: Bluett S. J. , Thom E. R. , Clark D. A. , Waugh C. D.
Published: February 2005

A 2-year evaluation of perennial ryegrass (Lolium perenne) infected with wild endophyte (Neotyphodium lolii), AR1 endophyte or no endophyte was carried out in Hamilton, New Zealand. In contrast to wild endophyte-infected ryegrass, AR1-infected ryegrass does not produce the alkaloids lolitrem B or ergovaline. Annual pasture production was similar across endophyte treatments, averaging 18.3 t DM/ha in year 1 and 13.8 t DM/ha in year 2, and ryegrass tiller density and botanical composition were unaffected by endophyte status. A combined analysis of 3 short-term milk production tests in late spring (Nov. 1999), summer (Jan. 2000) and autumn (Mar. 2000) in the first experiment, showed a 6.7% advantage in milk production to cows grazing AR1-infected ryegrass compared with those grazing wild endophyte-infected ryegrass pastures (P<0.05). Milk composition was similar in all test periods and ryegrass staggers was not observed on any treatment. In a second experiment, weaned dairy calves were continuously stocked on the pastures described above from late spring 2000 to autumn 2001 and grazed to a mean sward height of 5 cm. Average calf liveweight gain and total liveweight gain per hectare were similar across treatments over the 5-month period, averaging 0.8 kg/calf.day and 822 kg/ha, respectively. Calves grazing wild endophyte-infected ryegrass developed mild ryegrass staggers in January and February, coinciding with a peak lolitrem B concentration in this experiment of 2.3 mg/kg DM, while those grazing AR1-infected or endophyte-free ryegrass pastures did not develop staggers. Information is also presented on herbage and alkaloid intake, blood plasma prolactin concentration, and cow temperature and respiration rate. Results from this initial evaluation under dairying indicate that AR1-infected ryegrass can produce similar pasture yields as wild endophyte-infected ryegrass, while offering small improvements in milk yield with no incidence of ryegrass staggers in grazing animals.
Sulfide binding is mediated by zinc ions discovered in the crystal structure of a hydrothermal vent tubeworm hemoglobin
Authors: Flores Jason F. , Fisher Charles R. , Carney Susan L. , Green Brian N. , Freytag John K. , Schaeffer Stephen W. , Royer William E.
Published: February 2005

Key to the remarkable ability of vestimentiferan tubeworms to thrive in the harsh conditions of hydrothermal vents are hemoglobins that permit the sequestration and delivery of hydrogen sulfide and oxygen to chemoautotrophic bacteria. Here, we demonstrate that zinc ions, not free cysteine residues, bind sulfide in vestimentiferan hemoglobins. The crystal structure of the C1 hemoglobin from the hydrothermal vent tubeworm
Riftia pachyptila
has been determined to 3.15 Å and revealed the unexpected presence of 12 tightly bound Zn
2+
ions near the threefold axes of this D
3
symmetric hollow sphere. Chelation experiments on
R. pachyptila
whole-coelomic fluid and purified hemoglobins reveal a role for Zn
2+
ions in sulfide binding. Free cysteine residues, previously proposed as sulfide-binding sites in vestimentiferan hemoglobins, are found buried in surprisingly hydrophobic pockets below the surface of the
R. pachyptila
C1 molecule, suggesting that access of these residues to environmental sulfide is restricted. Attempts to reduce the sulfide-binding capacities of
R. pachyptila
hemoglobins by addition of a thiol inhibitor were also unsuccessful. These findings challenge the currently accepted paradigm of annelid hemoglobin evolution and adaptation to reducing environments.
Honey bees navigate according to a map-like spatial memory
Authors: Menzel Randolf , Greggers Uwe , Smith Alan , Berger Sandra , Brandt Robert , Brunke Sascha , Bundrock Gesine , Hülse Sandra , Plümpe Tobias , Schaupp Frank , Schüttler Elke , Stach Silke , Stindt Jan , Stollhoff Nicola , Watzl Sebastian
Published: February 2005

By using harmonic radar, we report the complete flight paths of displaced bees. Test bees forage at a feeder or are recruited by a waggle dance indicating the feeder. The flights are recorded after the bees are captured when leaving the hive or the feeder and are released at an unexpected release site. A sequence of behavioral routines become apparent: (
i
) initial straight flights in which they fly the course that they were on when captured (foraging bees) or that they learned during dance communication (recruited bees); (
ii
) slow search flights with frequent changes of direction in which they attempt to “get their bearings”; and (
iii
) straight and rapid flights directed either to the hive or first to the feeding station and then to the hive. These straight homing flights start at locations all around the hive and at distances far out of the visual catchment area around the hive or the feeding station. Two essential criteria of a map-like spatial memory are met by these results: bees can set course at any arbitrary location in their familiar area, and they can choose between at least two goals. This finding suggests a rich, map-like organization of spatial memory in navigating honey bees.
Differential control of peripheral circadian rhythms by suprachiasmatic-dependent neural signals
Authors: Guo Hongnian , Brewer Judy McKinley , Champhekar Ameya , Harris Ruth B. S. , Bittman Eric L.
Published: February 2005

Although dependent on the integrity of a central pacemaker in the suprachiasmatic nucleus of the hypothalamus (SCN), endogenous daily (circadian) rhythms are expressed in a wide variety of peripheral organs. The pathways by which the pacemaker controls the periphery are unclear. Here, we used parabiosis between intact and SCN-lesioned mice to show that nonneural (behavioral or bloodborne) signals are adequate to maintain circadian rhythms of clock gene expression in liver and kidney, but not in heart, spleen, or skeletal muscle. These results indicate that the SCN regulates expression of circadian oscillations in different peripheral organs by diverse pathways.
Role of the intestinal tight junction modulator zonulin in the pathogenesis of type I diabetes in BB diabetic-prone rats
Authors: Watts Tammara , Berti Irene , Sapone Anna , Gerarduzzi Tania , Not Tarcisio , Zielke Ronald , Fasano Alessio
Published: February 2005

Increased intestinal permeability has been observed in numerous human autoimmune diseases, including type-1 diabetes (T1D) and its' animal model, the BB-wor diabetic prone rat. We have recently described zonulin, a protein that regulates intercellular tight junctions. The objective of this study was to establish whether zonulin-dependent increased intestinal permeability plays a role in the pathogenesis of T1D. In the BB diabetic-prone rat model of T1D, intestinal intraluminal zonulin levels were elevated 35-fold compared to control BB diabetic-resistant rats. Zonulin up-regulation was coincident with decreased small intestinal transepithelial electrical resistance, and was followed by the production of autoantibodies against pancreatic beta cells, which preceded the onset of clinically evident T1D by ≈25 days. In those diabetic prone rats that did not progress to diabetes, both intraluminal zonulin and transepithelial electrical resistance were similar to those detected in diabetic-resistant animal controls. Blockade of the zonulin receptor reduced the cumulative incidence of T1D by 70%, despite the persistence of intraluminal zonulin up-regulation. Moreover, treatment responders did not seroconvert to islet cell antibodies. Combined together, these findings suggest that the zonulin-induced loss in small intestinal barrier function is involved in the pathogenesis of T1D in the BB diabetic-prone animal model.
Genetic and chemical analyses of the action mechanisms of sirtinol in
Arabidopsis
Authors: Dai Xinhua , Hayashi Ken-ichiro , Nozaki Hiroshi , Cheng Youfa , Zhao Yunde
Published: February 2005

The synthetic molecule sirtinol was shown previously to activate the auxin signal transduction pathway. Here we present a combination of genetic and chemical approaches to elucidate the action mechanisms of sirtinol in
Arabidopsis
. Analysis of sirtinol derivatives indicated that the “active moiety” of sirtinol is 2-hydroxy-1-naphthaldehyde (HNA), suggesting that sirtinol undergoes a series of transformations in
Arabidopsis
to generate HNA, which then is converted to 2-hydroxy-1-naphthoic acid (HNC), which activates auxin signaling. A key step in the activation of sirtinol is the conversion of HNA to HNC, which is likely catalyzed by an aldehyde oxidase. Mutations in any of the genes that are responsible for synthesizing the molybdopterin cofactor, an essential cofactor for aldehyde oxidases, led to resistance to sirtinol, probably caused by the compromised capacity of the mutants to convert HNA to HNC. We also showed that sirtinol and HNA could bypass the auxin polar transport system and that they were transported efficiently to aerial parts of seedlings, whereas HNC and 1-naphthoic acid were essentially not absorbed by
Arabidopsis
seedlings, suggesting that sirtinol and HNA are useful tools for auxin studies.
Absorption of homocitrulline from the gastrointestinal tract
Authors: Evered D. F. , Vadgama J. V.
Published: February 2005

1. Transport ofL-homocitrulline, an amino acid which occurs in milk products, was studied with rat small intestine in vitro and from the human mouth in vivo. Absorption was partially dependent, in both systems, on the presence of sodium ions.

2. Metabolic inhibitors decreasedL-homocitrulline uptake across the small intestine. Transport across the intestine did not occur against the concentration gradient but did show saturation kinetics.

3. The barbiturate, amytal, did not inhibit buccal absorption. Saturation kinetics were demonstrated.

4. Experiments were conducted withL-citrulline, or other amino acids, as possible inhibitors ofL-homocitrulline transport. Results were compatible with Na+-dependent carrier-mediated uptake across the buccal mucosa. Active transport could be involved with the small intestine assuming thatL-homocitrulline has a low affinity for the carrier system.
Intestinal absorption of calcium in rats given diets containing casein or amino acid mixture: the role of casein phosphopeptides
Authors: Lee Yeon Sook , Noguchi Tadashi , Naito Hiroshi
Published: February 2005

1. In an attempt to investigate calcium absorption in the rat during the postprandial period, with the least alteration of the physical environment, the undisturbed small intestine was ligated in situ 2·5 or 3·0 h after ingestion of a diet containing 200 g casein/kg or an equivalent amino acid mixture, or 925 g casein/kg. Estimation of Ca absorption was made by comparing the amount of soluble 40Ca or 45Ca in the contents of segments from the rats receiving 45Ca by intubation 30 min after withdrawal of food, ligated after a further 30 min, then killed after 0 or 30 min.

2. Under conditions such that the estimated amount of a marker, polyethylene glycol, in segments ligated in a defined position was little changed in rats killed 30 min apart, the difference in the amount of soluble 40Ca was much higher in the rats fed on the basal diet containing 200 g casein/kg than in other groups.

3. This specific effect on Ca absorption, particularly in the distal portion of the small intestine, could be seen also after 45Ca was directly injected into ligated segments in situ. The amount of 45Ca in the portal blood 15 min after injection of the label was also highest in the rats given the basal diet.

4. The results were in agreement with our previous findings that the formation and accumulation of casein phosphopeptides causes an increase in the amount of soluble Ca in the distal small intestine.
The influence of dietary iron and molybdenum on copper metabolism in calves
Authors: Humphries W. R. , Phillippo M. , Young B. W. , Bremner I.
Published: February 2005

1. Twenty heifer calves were allocated to four groups and maintained for 32 weeks on a diet based mainly on barley and straw and containing 4 mg copper/kg. The diet was supplemented with 0 or 800 mg iron/kg and 0 or 5 mg molybdenum/kg.

2. Liver and plasma Cu concentrations, erythrocyte superoxide dismutase (EC1.15.1.1) and plasma caeruloplasmin (EC1.16.3.1) activities decreased greatly and rapidly in all calves given the Fe or Mo supplements or both. Levels indicative of severe Cu deficiency were attained within 16 weeks. There were no significant differences in values in animals given Fe, Mo or Fe plus Mo.

3. Clinical signs of Cu deficiency developed after 20 weeks in the calves given the Mo supplement. Growth rates were reduced, skeletal lesions developed and hair texture and colour were affected. No such effects were observed in the calves given only the Fe supplement.

4. Plasma and liver Fe concentrations increased in calves given the Fe supplement but were not greatly affected by Mo, even when the calves were severely Cu-deficient.

5. The significance of the effects of Fe and Mo on Cu metabolism are discussed with special regard to the influence of soil ingestion on Cu availability and to the frequent lack of correlation between the Cu status of animals and their clinical condition.
Digestion of rumen bacteria in vitro
Authors: Wallace R. J.
Published: February 2005

1. A pepsin + pancreatin method was used to assess the digestibility of pure cultures of rumen bacteria and mixed bacteria prepared from rumen fluid.

2. Individual species of Gram-negative rumen bacteria were highly digestible, whereas Gram-positive species, especially cocci, were more resistant to digestion.

3. A similar difference was observed microscopically with mixed rumen bacteria, but the influence of the relative proportions of Gram-positive and Gram-negative bacteria on the digestibility of bacterial protein in rumen fluid was small.
Effects of exogenous glucose on glucose metabolism in the lactating goat in vivo
Authors: Chaiyabutr N. , Faulkner Anne , Peaker M.
Published: February 2005

1. Glucose turnover in fed and 48 h-starved lactating goats was determined during a glucose load of 500 μmol/min using a continuous infusion of [U-14C]- and [3-3H]glucose.

2. Endogenous rates of irreversible glucose turnover (i.e. total rates of irreversible glucose turnover minus the rate of exogenous glucose supply) were depressed during glucose loading by 14 and 62% in the fed and starved animals respectively.

3. Plasma glucose concentrations increased significantly by 57 and 88% in the fed and starved goats respectively. Plasma insulin concentrations increased by 108 and 128% in the fed and starved animals respectively.

4. Milk yields increased significantly (41%) in the starved animals during glucose loading, but were unaffected in fed animals.

5. In both the fed and 48 h-starved goats, mammary glucose metabolism via glycolysis and the pentose phosphate pathway appeared to be stimulated by glucose loading.
Fieldwork among Pastoral Nomads and in Sedentary Communities of Iran
Authors: Amanolahi Sekandar
Published: February 2005

Even as a high school student in Luristan I was interested in folklore, in recording folk tales, songs, and poems, and in the various customs of the different peoples of Iran. When I returned from the United States in 1974 with a Ph.D. in anthropology and started to teach at what then was Pahlavi University (now Shiraz University), I realized that my professional interest amounted to a scholarly mission, given the fact that so few anthropologists were active in Iran and how much there was to record ethnographically. As I like to travel (mostly by car so as to have easy and spontaneous access to locations of interest) and to interact with people, I have taken my work to many places. I have no problems making contacts or communicating with people of all walks of life, although gender is, of course, an issue. As a rule, I work on projects where I do not have to interact privately with women, or else where I can rely on the services of a female assistant.
The Ethnography of Children
Authors: Friedl Erika
Published: February 2005

More than half the population of Iran is under the age of seventeen, but despite these more than 30 million children and adolescents, social scientists know little about their experiences, culture, or history.

This ignorance is a reflection of what social scientists deem important. The dismissive attitude toward research with children is similar to earlier attitudes toward research with women: at best women were quantified and described. Most social scientists were male, seeing women from a male point of view. Out of the innocent arrogance that a male-dominated science breeds in its practitioners, women's own culture was largely ignored; “culture” was male culture. This changed only when women social scientists started to look at women through their own eyes.
Oil, Economic Diversification and the Democratic Process in Iran
Authors: Karshenas Massoud , Hakimian Hassan
Published: February 2005

Since 1979, Iran has witnessed important socio-economic and institutional changes and has been affected by significant economic and political upheavals. These years have witnessed a succession of oil booms and busts, external war, trade sanctions and of course, more recently, heightened internal strife within the state. After 25 years, however, Iran's political outlook seems opaque to most observers and the economic record is equally lacklustre with many Iranians experiencing a considerable retrogression in their living standards by regional and international standards.
The Significance of Economic History, and the Fundamental Features of the Economic History of Iran
Authors: Katouzian Homa
Published: February 2005

Just as natural history is the mother of the biological sciences, social history is the mother of the social sciences. Classical political economy was developed in a dynamic era, a period of European history where a series of long-term social developments were approaching their peak in the French Revolution and the Industrial Revolution of England. It is not at all surprising that Adam Smith and David Hume spent time with the French Physiocrats, notably Quesnay and Turgot, and with the Frenchphilosophes, especially though not exclusively Voltaire and Rousseau.

It was precisely the dynamic quality of the era that led economic and social and political theorists alike to look into the nature and causes of change, and therefore regard history as a principal source of the foundations of their knowledge. A similar process was taking place, but more slowly, among biologists who were trying to discover the nature of life and the origin of species, and the causes of long-term biological changes through time. Darwinism was in fact the end, not the beginning, of this process.
Road Traffic Change: A Catalyst for Segregation?
Authors: Bjørnskau Torkel
Published: February 2005

The paper presents the results from a study of whether road traffic changes can trigger segregation processes in accordance with Thomas Schelling's 'tipping-point model'. Based on register information of all persons who have lived in inner Oslo east in five neighbourhood types that differ with respect to road traffic development during the 1990s, it is concluded that there is a pattern of relocation quite consistent with the tipping-point model but only for some groups and in some neighbourhood types. There are more rapid and profound patterns of relocation in neighbourhoods with road traffic increase, than in neighbourhoods with traffic reductions and, in particular, families with children relocate in response to changes in the physical and social characteristics of the neighbourhood.
Information Technology and the Future of Cities: An Alternative Analysis
Authors: Panayides Alexandros , Kern Clifford R.
Published: February 2005

How will advances in telecommunications technology affect urban development? In this paper, we develop a general model where individuals involved in relationships use two modes of interaction, face-to-face and electronic communication. Each individual chooses the amount of interaction of each type to maximise her net pay-off from the relationships. Improvements in telecommunications technology may increase or decrease the demand for face-to-face interactions, depending on whether the cross-price elasticity of demand between face-to-face interactions and telecommunications is positive or negative. Embedding the model within a simple spatial framework shows that city size increases with electronic communications if the cross-elasticity is negative. The model presented here is closely related to that of Gaspar and Glaeser, and its conclusions are virtually identical, but they are derived from a simpler and arguably more descriptively accurate representation of the interdependence between face-to-face interactions and electronic communications.
Preventive home visits to older people in Southern Sweden
Authors: Theander Eva , Edberg Anna-Karin
Published: February 2005

Background: It seems urgent to further develop and modify models of preventive measures in order to prolong a healthy functional and social situation for older people, as this population is increasing globally. The aim of the study was to describe a Swedish model of preventive home visits for persons aged 78 years with the focus on the effect on physical and social well-being, and the participants' and the visitors' experience of the home visits. Method: Three annual visits were performed and included 150 persons, 78 years old at the first visit. Data were collected in the form of a structured interview with the persons who received the visits and as a questionnaire for their visitors. Results: Differences over time could be seen for the participants' physical and social activity, indicating that there was a deterioration between year one and two that was not seen in year three. The results further showed that the participants felt more secure and well informed as a result of the visits. The visitors said that they had gained a new, more positive view of older people and increased job satisfaction as a result of the visits and emphasized the impact on their own professional development. Conclusion: As no control group was used, the interpretation of effects concerning health factors has to be interpreted with caution. The visits did, however, have a positive impact on the participants and the visitors.