bluuebunny/crossref_metadata_2025 huggingface dataset:
Large cell neuroendocrine carcinoma of the ampulla of Vater with glandular differentiation: Figure 1
Authors: Cheng S-P , Yang T-L , Chang K-M , Liu C-L
Published: September 2004

Large cell neuroendocrine carcinoma of the ampulla of Vater is extremely rare. A 55 year old woman presented with an ampullary tumour causing pancreaticobiliary obstruction and a pancreaticoduodenectomy was performed. Microscopically, the tumour was diagnosed as a CD117 positive large cell neuroendocrine carcinoma with glandular differentiation. Four months later the patient developed a general recurrence. The metastatic tumours showed CD117 negativity and pure neuroendocrine features. The patient died of disease six months after diagnosis. It is postulated that the two components originated from a common multipotential stem cell. The clinical behaviour of ampullary large cell neuroendocrine carcinomas appears to be highly aggressive, with early metastases and a fatal outcome.
ON THE EQUIVALENCE BETWEEN NONLINEAR ELECTRODYNAMICS WITH ONE AND TWO POTENTIALS
Authors: SALIM J. M.
Published: September 2004

We present a model of a nonlinear electrodynamics with two potentials that allows the signals to propagates with constant velocity, as in linear Maxwell theory, and exhibit dual-symmetry.
MUSCLES WITHIN MUSCLES: THE CLASSICAL TRIPHASIC EMG BURST AND ITS APPLICABILITY TO SEGMENTS OF LARGE RADIATE AGONIST/ANTAGONIST MUSCLES
Authors: Wickham J. B. , Brown J. M. M. , Green R. , McAndrew D. J.
Published: September 2004

The purpose of the current study was to determine if the classically described triphasic EMG burst was applicable in describing the EMG patterns across the breadth of three large radiate muscles during the production of a rapid shoulder joint movement. Miniature (6.5 mm inter-electrode distance) bipolar surface electrodes were placed across the breadth of the pectoralis major (6 off), latissimus dorsi (6 off) and the deltoid (7 off). Subjects performed a series of rapid shoulder joint adduction movements (<400 ms) against the resistance of a free weight and pulley apparatus whilst seated in an experimental chair. EMG data sampled from the multiple recording sites of the three muscles identified four different types of EMG waveforms. This was based on the presence, or absence, of multiple bursts, the length of each burst and the level of the silent period between bursts from the same segment of a muscle. The four bursts included a one-burst pattern, a one-continuous burst pattern, a two-continuous burst pattern and a two non-continuous burst pattern. Upon further analysis it was established that a relationship existed between the type of burst displayed by a segment and the functional role of that segment (prime mover, synergist, primary or secondary antagonist), hence a uniform type of burst pattern was not apparent across the breadth of the agonist (pectoralis major and latissimus dorsi) and antagonist (deltoid) muscles. It was evident that the triphasic EMG burst was most applicable for the EMG patterns arising from the prime mover segments of the pectoralis major and the latissimus dorsi and the primary antagonist segment of the deltoid. In conclusion, these results suggest that caution is warranted if stating that popular motor control theories10, 11 based on EMG patterns produced by small agonist and antagonist muscles during rapid limb movement, apply to all segments of large radiate muscles.
THE HOMEOPATHIC PREPARATION TRAUMEEL® S COMPARED WITH NSAIDS FOR SYMPTOMATIC TREATMENT OF EPICONDYLITIS
Authors: Birnesser Heinz , Oberbaum Menachem , Klein Peter , Weiser Michael
Published: September 2004

Objective: To compare the homeopathic remedy Traumeel® S with standard NSAID therapy for effects on symptomatic relief in patients with diagnosed epicondylitis.

Methods: An observational, non-randomized study over 2 weeks in 184 patients with diagnosed epicondylitis from 38 primary care centers in Germany. At the start of the study, patients were given initial injections of either Traumeel® S or NSAID (unspecified; mainly diclofenac). Traumeel® S patients might have other Traumeel® S injections and other treatments were allowed, e.g. oral analgesics (in the NSAID group only) or physiotherapy. Treatments were evaluated on clinically relevant variables: three pain variables (local pressure pain, pain with movements, pain at rest) and two mobility variables (change in extensional joint mobility and change in torsional joint mobility).

Results: Both treatments significantly improved scores on all five variables with no significant differences in time to onset of action. Traumeel® S was equivalent to NSAIDs on all evaluated variables and was significantly superior to NSAID therapy on the variables pain at rest (p<0.01), torsional joint mobility (p<0.01), and extensional joint mobility (p<0.05). Patients' verdicts on the global outcome reflected the results, with the terms "very good" or "good", given by 71.0% of patients in the Traumeel® S group versus 44.2% of patients receiving NSAIDs. Tolerability was good in all groups.

Conclusion: Traumeel® S represents an appealing and well-tolerated alternative to NSAIDs for symptomatic treatment of epicondylitis.
VALIDATION OF THE USE OF A SKIN-MOUNTED DEVICE TO MEASURE OUT-OF-PLANE ROTATIONS OF THE SPINE FOR A ROWING ACTIVITY
Authors: Bull Anthony M. J. , Holt Peter J. , Wragg Paul , McGregor Alison H.
Published: September 2004

Objective: To assess the accuracy of a skin-mounted device to measure lumbar spinal rotations in rowers.

Methods: Nine subjects were each imaged in 12 extremes of lateral flexion and rotation in an open MR scanner, and the movement between external MR markers fixed to the skin, and the underlying vertebral bodies was quantified.

Results: The average error in measuring the changes in the lateral flexion and rotation between the MR markers and the underlying vertebral bodies was ±5.0° (95% CI 3.5–6.4°, S.E. 0.7°) for lateral flexion and 4.4° (95% CI 3.2–5.6°, S.E 0.6°) for lateral rotation (nine subjects).

Conclusions: This study has demonstrated the accuracy of using an externally mounted device to measure out-of-plane rotations for the extremes of motion achieved during a rowing activity, allowing this system to be used to quantify deviations in rowing technique. The method could be applied to other repetitive activities of the spine.
Acetyl-CoA provision and the acetyl group deficit at the onset of contraction in ischemic canine skeletal muscle
Authors: Roberts Paul A. , Loxham Susan J. G. , Poucher Simon M. , Constantin-Teodosiu Dumitru , Greenhaff Paul L.
Published: September 2004

We examined the effects of increasing acetylcarnitine and acetyl-CoA availability at rest, independent of pyruvate dehydrogenase complex (PDC) activation, on energy production and tension development during the rest-to-work transition in canine skeletal muscle. We aimed to elucidate whether the lag in PDC-derived acetyl-CoA delivery toward the TCA cycle at the onset of exercise can be overcome by increasing acetyl group availability independently of PDC activation or is intimately dependent on PDC-derived acetyl-CoA. Gracilis muscle pretreated with saline or sodium acetate (360 mg/kg body mass) (both n = 6) was sampled repeatedly during 5 min of ischemic contraction. Acetate increased acetylcarnitine and acetyl-CoA availability (both P < 0.01) above control at rest and throughout contraction ( P < 0.05), independently of differences in resting PDC activation between treatments. Acetate reduced oxygen-independent ATP resynthesis ∼40% ( P < 0.05) during the first minute of contraction. No difference in oxygen-independent ATP resynthesis existed between treatments from 1 to 3 min of contraction; however, energy production via this route increased ∼25% ( P < 0.05) above control in the acetate-treated group during the final 2 min of contraction. Tension development was ∼20% greater after 5-min contraction after acetate treatment than in control ( P < 0.05). In conclusion, at the immediate onset of contraction, when PDC was largely inactive, increasing cellular acetyl group availability overcame inertia in mitochondrial ATP regeneration. However, after the first minute, when PDC was near maximally activated in both groups, it appears that PDC-derived acetyl-CoA, rather than increased cellular acetyl group availability per se, dictated mitochondrial ATP resynthesis.
Response Properties of Single Auditory Nerve Fibers in the Mouse
Authors: Taberner Annette M. , Liberman M. Charles
Published: September 2004

The availability of transgenic and mutant lines makes the mouse a valuable model for study of the inner ear, and a powerful window into cochlear function can be obtained by recordings from single auditory nerve (AN) fibers. This study provides the first systematic description of spontaneous and sound-evoked discharge properties of AN fibers in mouse, specifically in CBA/CaJ and C57BL/6 strains, both commonly used in auditory research. Response properties of 196 AN fibers from CBA/CaJ and 58 from C57BL/6 were analyzed, including spontaneous rates (SR), tuning curves, rate versus level functions, dynamic range, response adaptation, phase-locking, and the relation between SR and these response properties. The only significant interstrain difference was the elevation of high-frequency thresholds in C57BL/6. In general, mouse AN fibers showed similar responses to other mammals: sharpness of tuning increased with characteristic frequency, which ranged from 2.5 to 70 kHz; SRs ranged from 0 to 120 sp/s, and fibers with low SR (<1 sp/s) had higher thresholds, and wider dynamic ranges than fibers with high SR. Dynamic ranges for mouse high-SR fibers were smaller (<20 dB) than those seen in other mammals. Phase-locking was seen for tone frequencies <4 kHz. Maximum synchronization indices were lower than those in cat but similar to those found in guinea pig.
Spinal Neurons That Express NK-1 Receptors Modulate Descending Controls That Project Through the Dorsolateral Funiculus
Authors: Khasabov Sergey G. , Ghilardi Joseph R. , Mantyh Patrick W. , Simone Donald A.
Published: September 2004

Selective ablation of spinal neurons possessing substance P receptors (NK-1 receptors) using the selective cytotoxin conjugate substance P-saporin (SP-SAP) decreases hyperalgesia and central sensitization. The mechanisms by which NK-1 expressing neurons modulate the excitability of other dorsal horn neurons are unclear. Because the majority of NK-1 expressing spinal neurons project rostrally, it is possible that they are part of a spinal-supraspinal circuitry that contributes to descending modulation of excitability of spinal nociceptive neurons. We therefore determined whether ablation of spinal neurons that possess the NK-1 receptor altered descending systems that travel via the dorsolateral funiculus (DLF). Spontaneous activity and responses of dorsal horn neurons evoked by mechanical (von Frey monofilaments) and heat (35–51°C) stimuli were determined before and after transection of the DLF and were compared in rats pretreated with intrathecal application of vehicle or SP-SAP. In vehicle-treated rats, transection of the DLF caused a 233% increase in mean spontaneous activity of neurons and enhanced their responses to mechanical and heat stimuli, whereas these increases in excitation were blocked in rats pretreated with SP-SAP. Importantly, SP-SAP alone had no effect on spontaneous or evoked activity in the absence of DLF transection. These results demonstrate that spinal neurons expressing the NK-1 receptor appear to play a pivotal role in regulating descending systems that modulate activity of nociceptive dorsal horn neurons.
Birnennamen Aus Hemşin: Vorarbeiten zur Feststellung und Beschreibung der Birnenarten und ihrer regionalen Namen im östlichen Schwarzmeergebiet
Authors: Bläsing Uwe
Published: September 2004

The article discusses a number of dialectal names for pears, which I collected in the Hamshen area of the Eastern Pontic range in Turkey. This study is the first attempt to give the etymology of these terms and to also describe the kind of pears meant by the respective names. As it is to be expected for Hamshen, which in former times was almost exclusively inhabited by an Armenian population, a great many of the pear names have a direct Armenian background. Others are of Pontic Greek origin, and a third group is represented by typical Turkish formations. The investigation showed that it was not possible to elucidate these names without considering the aspects of areal lingustics and cultural relationships. Irrespective of the language we can often observe several common patterns and motives in the formation of these terms. Thus, in addition to the 32 terms collected in Hamshen, many names taken from other languages of the area had to be included into the discussion.
System Design of a Quadrupedal Galloping Machine
Authors: Nichol J. Gordon , Singh Surya P.N. , Waldron Kenneth J. , Palmer Luther R. , Orin David E.
Published: September 2004

In this paper we present the system design of a machine that we have constructed to study a quadrupedal gallop gait. The gallop gait is the preferred high-speed gait of most cursorial quadrupeds. To gallop, an animal must generate ballistic trajectories with characteristic strong impacts, coordinate leg movements with asymmetric footfall phasing, and effectively use compliant members, all the while maintaining dynamic stability. In this paper we seek to further understand the primary biological features necessary for galloping by building and testing a robotic quadruped similar in size to a large goat or antelope. These features include high-speed actuation, energy storage, on-line learning control, and high-performance attitude sensing. Because body dynamics are primarily influenced by the impulses delivered by the legs, the successful design and control of single leg energetics is a major focus of this work. The leg stores energy during flight by adding tension to a spring acting across an articulated knee. During stance, the spring energy is quickly released using a novel capstan design. As a precursor to quadruped control, two intelligent strategies have been developed for verification on a one-legged system. The Levenberg-Marquardt on-line learning method is applied to a simple heuristic controller and provides good control over height and forward velocity. Direct adaptive fuzzy control, which requires no system modeling but is more computationally expensive, exhibits better response. Using these techniques we have been successful in operating one leg at speeds necessary for a dynamic gallop of a machine of this scale. Another necessary component of quadruped locomotion is high-resolution and high-bandwidth attitude sensing. The large ground impact accelerations, which cause problems for any single traditional sensor, are overcome through the use of an inertial sensing approach using updates from optical sensors and vehicle kinematics.
Optimal Gait Synthesis of a Seven-Link Planar Biped
Authors: Bessonnet Guy , Chessé Stéphane , Sardain Philippe
Published: September 2004

In this paper, we carry out the dynamics-based optimization of sagittal gait cycles of a planar seven-link biped using the Pontryagin maximum principle. Special attention is devoted to the double-support phase of the gait, during which the movement is subjected to severe limiting conditions. In particular, due to the fact that the biped moves as a closed kinematic chain, overactuation must be compatible with double, non-sliding unilateral contacts with the supporting ground. The closed chain is considered as open at front foot level. A full set of joint coordinates is introduced to formulate a complete Hamiltonian dynamic model of the biped. Contact forces at the front foot are considered as additional control variables of the stated optimal control problem. This is restated as a state-unconstrained optimization problem which is finally recast, using the Pontryagin maximum principle, as a two-point boundary value problem. This final problem is solved using a standard computing code. A gait sequence, comprising starting, cyclic, and stopping steps, is generated in the form of a numerical simulation.
Omnidirectional Hexapod Walking and Efficient Gaits Using Restrictedness
Authors: Fielding Michael R , Dunlop G Reg
Published: September 2004

The “restrictedness” of a hexapod robot’s legs is the degree to which their free movement is restricted in some way. Using the restrictedness to decide when to lift the legs has previously been shown to allow omnidirectional walking using a free gait as well as a tripod gait during straight-ahead walking. In this paper, we develop the previous system to improve the range of forward walking gaits exhibited by the restrictedness controller to include a range of “wave gaits.” A simplified robot model was used for an off-line search for the optimal restrictedness components for forward walking. Experimental results from the small hexapod “Hamlet” are presented to show the worth of the restrictedness concept and the modeling process.
Stability and Traction Optimization of a Reconfigurable Wheel-Legged Robot
Authors: Grand Christophe , Benamar Faïz , Plumet Frédéric , Bidaud Philippe
Published: September 2004

Actively articulated locomotion systems such as hybrid wheel-legged vehicles are a possible way to enhance the locomotion performance of an autonomous mobile robot. In this paper, we address the control of the wheel-legged robot Hylos traveling on irregular sloping terrain. The redundancy of such a system is used to optimize both the balance of traction forces and the tipover stability. The general formulation of this optimization problem is presented, and a suboptimal but computationally efficient solution is proposed. Then, an algorithm to control the robot posture, based on a velocity model, is described. Finally, this algorithm is validated through simulations and experiments that show the capabilities of such a redundantly actuated vehicle to enhance its own safety and autonomy in critical environments.
A novel celecoxib derivative, OSU03012, induces cytotoxicity in primary CLL cells and transformed B-cell lymphoma cell line via a caspase- and Bcl-2–independent mechanism
Authors: Johnson Amy J. , Smith Lisa L. , Zhu Jiuxiang , Heerema Nyla A. , Jefferson Sara , Mone Andrew , Grever Michael , Chen Ching-Shih , Byrd John C.
Published: September 2004

Chronic lymphocytic leukemia (CLL) is an incurable adult leukemia characterized by disrupted apoptosis. OSU03012 is a bioavailable third-generation celecoxib derivative devoid of cyclooxygenase-2 inhibitory activity that potently induces apoptosis in prostate cancer cell lines and is being developed as an anticancer therapy in the National Cancer Institute (NCI) Rapid Access to Intervention Development (RAID) program. We assessed the ability of OSU03012 to induce apoptosis in primary CLL cells and the mechanism by which this occurs. The LC50 (lethal concentration 50%) of OSU03012 at 24 hours was 7.1 μM, and this decreased to 5.5 μM at 72 hours. Additionally, we have demonstrated that OSU03012 mediates apoptosis by activation of the intrinsic, mitochondrial pathway of apoptosis but also activates alternative cell death pathways that are caspase independent. The early activation of both caspase-dependent and -independent pathways of apoptosis is novel to OSU03012 and suggests it has great potential promise for the treatment of CLL. Moreover, unlike the great majority of therapeutic agents used to treat leukemia or other forms of cancer, OSU03012 induces cell death entirely independent of bcl-2 expression. Overall, these data provide justification for further preclinical development of OSU03012 as a potential therapeutic agent for CLL.
Leukotriene B4 plays a pivotal role in CD40-dependent activation of chronic B lymphocytic leukemia cells
Authors: Runarsson Gudmundur , Liu Anquan , Mahshid Yilmaz , Feltenmark Stina , Pettersson Annika , Klein Eva , Björkholm Magnus , Claesson Hans-Erik
Published: September 2004

Biosynthesis of leukotrienes (LTs) occurs in human myeloid cells and B lymphocytes. However, the function of leukotrienes in B lymphocytes is unclear. Here, we report that B-cell chronic lymphocytic leukemia (B-CLL) cells produce leukotriene B4, and that specific leukotriene biosynthesis inhibitors counteracted CD40-dependent activation of B-CLL cells. Studies on the expression of the high-affinity receptor for LTB4 (BLT1) by flow cytometry analysis showed that the receptor was expressed, to a varying degree, in all investigated B-CLL clones. At a concentration of 100 nM, the drugs BWA4C (a specific 5-lipoxygenase inhibitor) and MK-886 (a specific 5-lipoxygenase activating protein inhibitor) markedly inhibited CD40-induced DNA synthesis (45% and 38%, respectively) and CD40-induced expression of CD23, CD54, and CD150. Addition of exogenous LTB4 (150 nM) almost completely reversed the effect of the inhibitors on DNA synthesis and antigen expression. Taken together, the results of the present study suggest that leukotriene biosynthesis inhibitors may have a therapeutic role in B-CLL.
Evolution of sexual asymmetry
Authors: Czárán Tamás L , Hoekstra Rolf F
Published: September 2004

Background

The clear dominance of two-gender sex in recent species is a notorious puzzle of evolutionary theory. It has at least two layers: besides the most fundamental and challenging question why sex exists at all, the other part of the problem is equally perplexing but much less studied. Why do most sexual organisms use a binary mating system? Even if sex confers an evolutionary advantage (through whatever genetic mechanism), why does it manifest that advantage in two, and exactly two, genders (or mating types)? Why not just one, and why not more than two?

Results

Assuming that sex carries an inherent fitness advantage over pure clonal multiplication, we attempt to give a feasible solution to the problem of the evolution of dimorphic sexual asymmetry as opposed to monomorphic symmetry by using a spatial (cellular automaton) model and its non-spatial (mean-field) approximation. Based on a comparison of the spatial model to the mean-field approximation we suggest that spatial population structure must have played a significant role in the evolution of mating types, due to the largely clonal (self-aggregated) spatial distribution of gamete types, which is plausible in aquatic habitats for physical reasons, and appears to facilitate the evolution of a binary mating system.

Conclusions

Under broad ecological and genetic conditions the cellular automaton predicts selective removal from the population of supposedly primitive gametes that are able to mate with their own type, whereas the non-spatial model admits coexistence of the primitive type and the mating types. Thus we offer a basically ecological solution to a theoretical problem that earlier models based on random gamete encounters had failed to resolve.
The vaa locus of Mycoplasma hominis contains a divergent genetic islet encoding a putative membrane protein
Authors: Boesen Thomas , Emmersen Jeppe , Baczynska Agata , Birkelund Svend , Christiansen Gunna
Published: September 2004

Background

The Mycoplasma hominis vaa gene encodes a highly variable, surface antigen involved in the adhesion to host cells. We have analysed the structure of the vaa locus to elucidate the genetic basis for variation of vaa.

Results

Mapping of vaa on existing physical maps of five M. hominis isolates by pulsed field gel electrophoresis revealed that vaa is located in a genomic region containing the majority of other characterized membrane protein genes of M. hominis. Sequencing of an 11 kb region containing the vaa locus of M. hominis isolate 132 showed the presence of conserved housekeeping genes at the borders of the region, uvrA upstream and the hitABL operon downstream to vaa. Analysis of 20 M. hominis isolates revealed that the vaa upstream region was conserved whereas the downstream region was highly variable. In isolate 132 this region contained an open reading frame (ORF) encoding a putative 160 kDa membrane protein. Homologous ORFs were present in half of the isolates, whereas this ORF, termed vmp (variable membrane protein), was deleted from the locus in the remaining isolates. Compellingly, the conserved upstream region and variable downstream region of vaa correlates with the genetic structure of vaa itself which consists of a conserved 5' end and a variable 3' end containing a variable number of exchangeable sequence cassettes.

Conclusion

Our data demonstrate that the vaa locus contains a divergent genetic islet, and indicate pronounced intraspecies recombination. The high variability level of the locus indicate that it is a chromosomal 'hot spot', presumably important for sustaining diversity and a high adaptation potential of M. hominis.
A reverse genetic screen in Drosophila using a deletion-inducing mutagen
Authors: Nairz Knud , Zipperlen Peder , Dearolf Charles , Basler Konrad , Hafen Ernst
Published: September 2004

We report the use of the cross-linking drug hexamethylphosphoramide (HMPA), which introduces small deletions, as a mutagen suitable for reverse genetics in the model organism Drosophila melanogaster. A compatible mutation-detection method based on resolution of PCR fragment-length polymorphisms on standard DNA sequencers is implemented. As the spectrum of HMPA-induced mutations is similar in a variety of organisms, it should be possible to transfer this mutagenesis and detection procedure to other model systems.
Characterization of a fractured granite using radio magnetotelluric (RMT) data
Authors: Linde Niklas , Pedersen Laust B.
Published: September 2004

We applied tensor radio magnetotellurics (RMT) in the 10–250 kHz frequency range to study major fracture zones on Ävrö, a small island (1.6 × 1.2 km2) in southeastern Sweden with bedrock dominated by highly resistive granite. The interpretation of a 950‐m RMT profile was facilitated by seismic reflection and borehole data but was complicated (1) by possible 3D effects of the surrounding sea and (2) because the quasi‐static assumption is violated. Inversions based on the quasi‐static assumption give severely distorted models in this type of environment. Inversion codes that include displacement currents are restricted to 1D structures. Therefore, 2D inversions were applied to lower frequencies only. The central part of the inverted profile showed a 30–40‐m‐thick weathered layer over an almost intact bedrock down to a depth of at least 200 m, where higher salinity and/or fracturing yielded higher conductivities. The first 200 m of the profile revealed a major fracture zone, which coincided with a seismic reflector. We used 3D forward modeling to understand the sea effect and to model the conductor in three dimensions. We believe that 3D forward modeling is a highly valuable tool to distinguish known 3D effects (i.e., the sea) from regional 2D features of interest. We suggest that water flow at Ävrö is dominated by a few major fracture zones.
A parallel finite‐difference approach for 3D transient electromagnetic modeling with galvanic sources
Authors: Commer Michael , Newman Gregory
Published: September 2004

A parallel finite‐difference algorithm for the solution of diffusive, three‐dimensional (3D) transient electromagnetic field simulations is presented. The purpose of the scheme is the simulation of both electric fields and the time derivative of magnetic fields generated by galvanic sources (grounded wires) over arbitrarily complicated distributions of conductivity and magnetic permeability. Using a staggered grid and a modified DuFort‐Frankel method, the scheme steps Maxwell's equations in time. Electric field initialization is done by a conjugate‐gradient solution of a 3D Poisson problem, as is common in 3D resistivity modeling. Instead of calculating the initial magnetic field directly, its time derivative and curl are employed in order to advance the electric field in time. A divergence‐free condition is enforced for both the magnetic‐field time derivative and the total conduction‐current density, providing accurate results at late times. In order to simulate large realistic earth models, the algorithm has been designed to run on parallel computer platforms. The upward continuation boundary condition for a stable solution in the infinitely resistive air layer involves a two‐dimensional parallel fast Fourier transform. Example simulations are compared with analytical, integral‐equation and spectral Lanczos decomposition solutions and demonstrate the accuracy of the scheme.
Effects of gas‐ and water‐filled boreholes on the amplitudes of crosshole georadar data as inferred from experimental evidence
Authors: Tronicke Jens , Holliger Klaus
Published: September 2004

A special packer system is developed that replaces the water in a borehole with a gas and thus allows us to isolate the effects of the borehole filling media on crosshole georadar measurements. We demonstrate experimentally that the radiative characteristics of borehole georadar antennas differ substantially for gas‐ and water‐filled boreholes. The main differences are a spectral shift to lower frequencies and a less focused radiation pattern in the case of a water‐filled borehole. These effects are correctly predicted by a basic finite‐difference time‐domain (FDTD) modeling approach, which offers the prospect for improving the quality of amplitude inversions from crosshole georadar data.
Data‐driven adaptive decomposition of multicomponent seabed recordings
Authors: Muijs Remco , Robertsson Johan O. A. , Holliger Klaus
Published: September 2004

Dual‐sensor (hydrophone and three‐component geophone) data recorded on the sea floor allow the elastic wavefield to be decomposed into its upgoing and downgoing P‐ and S‐wave components. Most decomposition algorithms require accurate knowledge of the elastic properties of the sea floor in the vicinity of the receivers and properly calibrated sensors, in order for the data to be a faithful vector representation of the ground motion. We present a multistep adaptive decomposition scheme that provides the necessary information directly from the data by imposing constraints on intermediate decomposition results. The proposed scheme requires no a priori information and only a minimal amount of user‐defined input, thus allowing multicomponent data to be decomposed in an automated data‐driven fashion. The performance of the technique is illustrated using seabed data acquired in the North Sea with prototype single sensors (multicomponent geophones individually sampled). Realistic sea floor properties and sensor calibration operators are obtained, and elastic decomposition of the calibrated data generally yields good results. Dominant water‐layer reverberations are successfully attenuated and primary reflections are substantially enhanced in the computed upgoing P‐wave potential just below the sea floor. In contrast, the result for the upgoing S‐wave potential is somewhat less convincing; although the energy of water‐layer multiples is substantially reduced, notable amounts of undesired multiple energy remain in this section after decomposition, particularly at high offsets. These imperfections may point to inaccuracies in the parametrization of the sea floor or remaining inaccuracies in the vector fidelity of the horizontal geophone recordings. Nevertheless, the results obtained with the extended data‐driven decomposition scheme are at least comparable to previously published results.
Heterogeneity of Joy in Infancy
Authors: Aksan Nazan , Kochanska Grazyna
Published: September 2004

We examined 7‐month‐old infants' responses to 6 joy‐eliciting episodes. Three episodes included and 3 did not include a major social‐interactive component. Confirmatory factor analysis of infants' joy reactions in these episodes revealed that a 2‐factor model significantly improved the fit over a single‐factor solution. Those 2 factors represented infants' social versus nonsocial joy reactions. Different correlates of those factors supported their external validity. Only social joy was associated with the infants' positive emotional tone observed during naturalistic interactions with their mothers and fathers, and with the parents' ratings of the child's positive affect during social interactions in their daily lives. Social joy may be an early antecedent of future positive emotionality traits related to communal and interpersonal aspects of experience.
Cathepsin L protease (CPL-1) is essential for yolk processing during embryogenesis in Caenorhabditis elegans
Authors: Britton Collette , Murray Linda
Published: September 2004

Cysteine proteases are involved in the degradation of intracellular and extracellular proteins, although their precise roles in vivo are not well understood. Here we characterise a genetic mutant of the Caenorhabditis elegans cathepsin L protease gene cpl-1. CPL-1 is provided maternally and is essential for C. elegans embryogenesis. Immunofluorescence and electron microscopy data show that yolk endocytosis and initial yolk platelet formation occur normally in cpl-1 mutant oocytes and embryos. However, at around the 8-12 cell stage of embryogenesis, yolk platelets begin to aggregate and these enlarged yolk platelets fill the cytoplasm of cpl-1 mutant embryos. Coincident with this aggregation is loss of fluorescence from a yolk green fluorescent protein (YP170::GFP). This suggests that loss of CPL-1 activity leads to aberrant processing and/or conformational changes in yolk proteins, resulting in abnormal platelet fusion. This study has relevance to the abnormal fusion and aggregation of lysosomes in cathepsin L-deficient mice and to other lysosomal disorders.
Synthesis and Electrochemical Properties of Single-crystal CdV2O6 Nanowire Arrays
Authors: Chen Xiangying , Wang Xiong , Wang Zhenghua , Wan Junxi , Liu Jianwei , Qian Yitai
Published: September 2004

Single-crystal cadmium vanadate (CdV2O6) nanowire arrays with the average diameter of 100 nm and length of up to 20 μm were fabricated by a hydrothermal process at 140 °C for 12 h. Electrochemical test shows that these nanowire arrays deliver a relatively large discharge capacity of 90 mA h g−1 vs Li metal at 0.1 mA cm−2 (voltage window of 3.2–2.0 V) compared with that of bulk CdV2O6. The obtained sample might find possible application as an electrode material in lithium ion batteries.
Synthesis and Luminescent Properties of a New Twisted Copolymer Containing Phenylenevinylene and Spirobifluorene
Authors: Huang Bing , Li Jun , Shao Pin , Qin Jingui , Jiang Zuoquan , Yu Gui , Liu Yunqi
Published: September 2004

A new twisted polymer, poly[9,9′-spirobifluoren-2,2′-ylene-vinylene-alt-2,5-di(n-buthoxy)-1,4-phenylene-vinylene] (PSBF-PV), which consists of phenylenevinylene chromophores linked through 9,9′-spirobifuorene, was synthesized through the Horner–Emons condensation. PSBF-PV showed strong green emission in solution and film. The single-layer light-emitting diode (LED) exhibited weak emission, and an improved performance with the maximum external quantum efficiency of 0.25% and luminance maxima of 1168 cd/m2 was achieved using Alq3 as electron injection layer in double layer LED for PSBF-PV.
Photochromism of a Diarylethene Trimer in a Bulk Amorphous Phase
Authors: Tomari Arisa , Yamaguchi Tadatsugu , Sakamoto Naotaka , Fujita Yuji , Irie Masahiro
Published: September 2004

A photochromic compound having three diarylethene units was synthesized and its photochromic performance was examined in hexane solution as well as in a bulk amorphous phase. The compound formed a stable amorphous solid with Tg of 120 °C and the solid exhibited a reversible color change upon irradiation with UV and visible light.
Redox-controlled Luminescence of a Cyclometalated Dinuclear Platinum Complex Bridged with Pyridine-2-thiolate Ions
Authors: Koshiyama Tamami , Omura Ai , Kato Masako
Published: September 2004

A cyclometalated dinuclear platinum(II) complex bridged with pyridine-2-thiolate ions, [Pt2(ppy)2(pyt)2] (Hppy = 2-phenylpyridine, Hpyt = pyridine-2-thiol) and its oxidized platinum(III) complex, [Pt2Cl2(ppy)2(pyt)2] have been synthesized and characterized. The divalent complex exhibits intense red luminescence both in solution and in the solid states. Corresponding to the short Pt···Pt distance (2.849(1) Å) for [Pt2(ppy)2(pyt)2], the reversible conversion between the divalent and trivalent complexes occurs easily with appearance and disappearance of the luminescence.
Synthesis of Li[Ni1/3Co1/3Mn1/3]O2−zFz via Coprecipitation
Authors: Myung Seung-Taek , Kim Gil-Ho , Sun Yang-Kook
Published: September 2004

Li[Ni1/3Co1/3Mn1/3]O2−zFz (z = 0–0.15) were synthesized via co-precipitation followed by high-temperature heat treatment. From X-ray diffraction investigation, it was found that the as-prepared powders showed the layered Li[Ni1/3Co1/3Mn1/3]O2−zFz (z = 0–0.15) having α-NaFeO2 structure (space group: ). Though the initial discharge capacities of Li[Ni1/3Co1/3Mn1/3]O2−zFz is somewhat smaller, however, the capacity retention and thermal stability at highly oxidized state were significantly improved comparing to the undoped Li[Ni1/3Co1/3Mn1/3]O2. Fluorine substitution for oxygen made it possible to use the cathode material at 4.6 V cut-off limit.
A Cation-exchange Resin Promoted Imino Aldol Reaction, Leading to the Synthesis of 2-Isocephem and 2-Oxa-isocephem
Authors: Shimizu Makoto , Tachi Masanori , Hachiya Iwao
Published: September 2004

Imino aldol reaction of ketene silyl acetals with the chiral imine 1 proceeds smoothly to giveβ-amino esters in good yields with high diasetereoselectivity under the influence of a cation-exchange resin, and the subsequent functional group transformations provide a formal synthesis of 2-isocephem and 2-oxa-isocephem β-lactam antibiotics.
Photochromic Properties of Diarylethene Maleimide Derivatives in Polar Solvents
Authors: Yamaguchi Tadatsugu , Irie Masahiro
Published: September 2004

Diarylmaleimide derivatives having methoxy, phenyl, or cyano group as a nitrogen substituent were synthesized in an attempt to prepare photochromic compounds which exhibit photochromic reactivity even in polar solvents. Although the derivatives having methoxy or phenyl group did not undergo photochromism in polar solvents, the derivative having a cyano group showed photochromism even in polar solvents.
Stereoselective Synthesis of 19-Hydroxytaxoid Using Intramolecular Pinacol Coupling Reaction
Authors: Mukaiyama Teruaki , Ogawa Yasuyuki , Kuroda Kiichi , Matsuo Jun-ichi
Published: September 2004

The ABC-ring system of 19-hydroxytaxol is stereoselectively constructed by intramolecular pinacol coupling of diketone 12 with low valent titanium species prepared from TiCl2 and LiAlH4. After manipulations of hydroxy protecting groups, a new 19-hydroxytaxoid 18 was afforded by olefination of vicinal diol part of 17.
Why Does the Cyclical Behavior of Real Wages Change Over Time?
Authors: Huang Kevin X. D , Liu Zheng , Phaneuf Louis
Published: September 2004

The cyclical behavior of real wages has evolved from mildly countercyclical during the interwar period to modestly procyclical in the postwar era. This paper presents a general-equilibrium business-cycle model that helps explain the evolution. In the model, changes in the real wage cyclicality arise from interactions between nominal wage and price rigidities and an evolving input-output structure.
Are Emily and Greg More Employable Than Lakisha and Jamal? A Field Experiment on Labor Market Discrimination
Authors: Bertrand Marianne , Mullainathan Sendhil
Published: September 2004

We study race in the labor market by sending fictitious resumes to help-wanted ads in Boston and Chicago newspapers. To manipulate perceived race, resumes are randomly assigned African-American- or White-sounding names. White names receive 50 percent more callbacks for interviews. Callbacks are also more responsive to resume quality for White names than for African-American ones. The racial gap is uniform across occupation, industry, and employer size. We also find little evidence that employers are inferring social class from the names. Differential treatment by race still appears to still be prominent in the U.S. labor market.
Determinants of Long-Term Growth: A Bayesian Averaging of Classical Estimates (BACE) Approach
Authors: Sala-i-Martin Xavier , Doppelhofer Gernot , Miller Ronald I
Published: September 2004

This paper examines the robustness of explanatory variables in cross-country economic growth regressions. It introduces and employs a novel approach, Bayesian Averaging of Classical Estimates (BACE), which constructs estimates by averaging OLS coefficients across models. The weights given to individual regressions have a Bayesian justification similar to the Schwarz model selection criterion. Of 67 explanatory variables we find 18 to be significantly and robustly partially correlated with long-term growth and another three variables to be marginally related. The strongest evidence is for the relative price of investment, primary school enrollment, and the initial level of real GDP per capita.
The Cost of Business Cycles Under Endogenous Growth
Authors: Barlevy Gadi
Published: September 2004

Robert E. Lucas, Jr. argued that the welfare gains from reducing aggregate consumption volatility are negligible. Subsequent work that revisited his calculation continued to find small welfare benefits, further reinforcing the perception that business cycles do not matter. This paper argues instead that fluctuations can affect welfare, by affecting the growth rate of consumption. I show that fluctuations can reduce growth starting from a given initial consumption, which can imply substantial welfare effects as Lucas himself observed. Empirical evidence suggests the welfare effects are likely to be substantial, about two orders of magnitude greater than Lucas' original estimates.
The Long and Short of the Canada-U.S. Free Trade Agreement
Authors: Trefler Daniel
Published: September 2004

The Canada-U.S. Free Trade Agreement provides a unique window onto the effects of a reciprocal trade agreement on an industrialized economy (Canada). For industries that experienced the deepest Canadian tariff cuts, the contraction of low-productivity plants reduced employment by 12 percent while raising industry-level labor productivity by 15 percent. For industries that experienced the largest U.S. tariff cuts, plant-level labor productivity soared by 14 percent. These results highlight the conflict between those who bore the short-run adjustment costs (displaced workers and struggling plants) and those who are garnering the long-run gains (consumers and efficient plants).
Running to Keep in the Same Place: Consumer Choice as a Game of Status
Authors: Hopkins Ed , Kornienko Tatiana
Published: September 2004

If individuals care about their status, defined as their rank in the distribution of consumption of one “positional” good, then the consumer's problem is strategic as her utility depends on the consumption choices of others. In the symmetric Nash equilibrium, each individual spends an inefficiently high amount on the status good. Using techniques from auction theory, we analyze the effects of exogenous changes in the distribution of income. In a richer society, almost all individuals spend more on conspicuous consumption, and individual utility is lower at each income level. In a more equal society, the poor are worse off.
A multi-phase telepsychiatry programme in Michigan: organizational factors affecting utilization and user perceptions
Authors: Whitten Pamela , Kuwahara Emily
Published: September 2004

Over the last few years, telepsychiatry services in Michigan have been developed by LifeWays, a Medicaid-managed behavioural health-care organization. The project had four phases, involving the introduction of telepsychiatry services between a rural and an urban clinic, to a crisis intervention centre, to a youth detention centre and to patients' homes. The role of organizational issues in the success of the programme was examined through patient interviews, provider interviews, patient and provider pre- and post-project focus groups, and service documents. Utilization data were obtained from activity logs and patient charts. During the study, 297 clients received 578 teleconsultations. Almost 97% of the telepsychiatry visits were scheduled. Telemedicine usage varied between the four project phases. The reasons for its variation in use included provider roles, existing organizational strategic goals and resources, the inherent organizational culture and quirks, and leadership and managerial factors. The major difficulties stemmed from the providers and the organization itself. There is tremendous potential for telepsychiatry and the ways in which organizational variables can be managed to influence the success of telepsychiatry programmes deserve further study.
The Functions of Breast Cancer Susceptibility Gene 1 (BRCA1) Product and Its Associated Proteins
Authors: Irminger-Finger I. , Siegel B.D. , Leung W.-C.
Published: September 2004

About half of the familial breast cancer cases are found to bear mutations in the breast cancer susceptibility gene 1 (
Being at the Right Place at the Right Time: The Role of Nuclear Transport in Dynamic Transcriptional Regulation in Yeast
Authors: Görner W. , Schüller C. , Ruis. H.
Published: September 2004

As a consequence of compartmentalization in eukaryotic cells, the transcriptional response to extracellular stimuli requires signals to be transmitted from the cytoplasm to the nucleus. Thus, nuclear import and export of signal transduction and transcription factors provide an important level of transcriptional control in eukaryotes. Recent investigations have illustrated the importance of this control for dynamic gene expression, as will be discussed on transcriptional activators and repressors (Mac1p, Mig1p, Msn2p/4p, Swi5p) and protein kinases (Hog1p, Sty1/Spc1, protein kinase A).
A Quantitative Map of the Circuit of Cat Primary Visual Cortex
Authors: Binzegger Tom , Douglas Rodney J. , Martin Kevan A. C.
Published: September 2004

We developed a quantitative description of the circuits formed in cat area 17 by estimating the “weight” of the projections between different neuronal types. To achieve this, we made three-dimensional reconstructions of 39 single neurons and thalamic afferents labeled with horseradish peroxidase during intracellular recordingsin vivo. These neurons served as representatives of the different types and provided the morphometrical data about the laminar distribution of the dendritic trees and synaptic boutons and the number of synapses formed by a given type of neuron. Extensive searches of the literature provided the estimates of numbers of the different neuronal types and their distribution across the cortical layers. Applying the simplification that synapses between different cell types are made in proportion to the boutons and dendrites that those cell types contribute to the neuropil in a given layer, we were able to estimate the probable source and number of synapses made between neurons in the six layers. The predicted synaptic maps were quantitatively close to the estimates derived from the experimental electron microscopic studies for the case of the main sources of excitatory and inhibitory input to the spiny stellate cells, which form a major target of layer 4 afferents. The map of the whole cortical circuit shows that there are very few “strong” but many “weak” excitatory projections, each of which may involve only a few percentage of the total complement of excitatory synapses of a single neuron.