bluuebunny/crossref_metadata_2025 huggingface dataset:
An analysis on malfunction of a flip‐flop due to impulsive noise on power supply
Authors: Tsukagoshi Tsuneo , Nitta Shuichi , Mutoh Atsuo
Published: September 2003

To dynamically analyze the output inversion mechanism due to impulsive noise applied on a DC power supplyVcc, assuming that a flip‐flop consisting of two transistors is used as the power supply noise sensor, the authors propose a simple circuit model not based on a nonlinear transistor model and a simple inversion model for performing a voltage comparison between the output pinVc1[see Fig. 1(a)] and the applied voltageVinof the power supply to determine whether or not inversion occurred. They also propose a technique for estimating noise immunity from transient response characteristics of the flip‐flop, which were obtained by using these models, and compare the estimated values obtained according to this technique with simulation values using SPICE and experimental values to verify the validity of this model within a range limited by the time constantTcof the simple circuit model [consisting ofRc1,R12, andC1in Fig. 1(d)] and the overdriving factor (ODF) of the transistors. The results clearly indicated that the time constantTcof the simple circuit model produced a response delay for output pinVc1relative to the applied voltageVinof the power supply on which the impulsive noise was applied, that an inverted potential gradient for whichVc1>Vinwas temporarily generated with the power supply voltage when the power supply voltage dropped, that this caused the current to flow backwards to the power supply side, and that making the base current of the transistor go in the negative direction is the cause of the output inversion. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(10): 36–50, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10187
Size reduction of the door seal structure of a microwave oven by the FD‐TD method
Authors: Kusama Yusuke , Hashimoto Osamu , Makida Minoru
Published: September 2003

Assuming a choke groove depth of half the present value, the FD‐TD method is used to obtain a value for the effectiveness of shielding against leakage waves that is very close to the actual value, including higher modes. To reduce computation time, the optimum dimension is first calculated for a TEM mode wave incident on a choke groove with a two‐dimensional cross section. Using the calculated optimal data, a three‐dimensional choke groove with periodic slits is analyzed and evaluated. To further compensate for the degradation of shielding effectiveness due to reduction in size, the case in which a lossy material and the groove are combined is also investigated. A choke based on the results of the analysis gave a measured shielding effectiveness of approximately 31 dB, providing an experimental demonstration of the validity of the analysis. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(10): 73–83, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10190
Rotation invariant image template matching based on correlation of curvature distribution
Authors: Saitoh Fumihiko
Published: September 2003

This paper proposes a method of searching for a target image area that has an arbitrary location and inclination in an objective image. The method uses the curvature of the edge pixels, which is invariant to the location and inclination of a target image area. The curvature of an edge pixel and the distance between the central pixel and the edge pixel are measured in a circular image area. The stored value in the two‐dimensional space that is spread by the curvature and the distance is incremented. This process is repeated about all edge pixels in the circular image area. The matching is executed between the two‐dimensional spaces that are generated by the circular template image and generated by a circular image area in an objective image. The experimental results show that the recognition rate of the target image areas recorded 97.8% of four kinds of images. The averaged processing time to search the target image areas was 20.4 seconds. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 145(4): 56–3, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10235
Percutaneous toxicokinetic and repeated cutaneous contact studies with ethylene glycol monohexyl ether
Authors: Ballantyne Bryan , Jensen Charles B. , Weaver Elizabeth V.
Published: September 2003

Ethylene glycol monohexyl ether (EGHE; CAS no. 112‐54‐4) is a liquid industrial chemical with a potential for skin contact. The toxicokinetics of EGHE was investigated in Fischer 344 rats and New Zealand White rabbits by intravenous (i.v.) and 48‐h occluded epicutaneous dosing. Given i.v. to male rats (2.5–25 mg kg−1) [14C]EGHE demonstrated ﬁrst‐order kinetics. Carbon‐14 was eliminated mainly in urine (68–74%) as metabolites, with no free EGHE. The plasma free EGHE concentration declined rapidly post‐dosing and was not detectable by 8 h. Similar results were obtained for [14C]EGHE given i.v. to male rabbits in the dosage range 1–10 mg kg−1, except that the metabolism of EGHE was more rapid, with no free EGHE being detectable in plasma by 1 h post‐dosing. After cutaneous dosing of male and female rats with 25 mg kg−1, there was rapid percutaneous absorption, with >95% of the radiochemical dose being recovered. Percutaneous bioavailability was >75%. Carbon‐14 was excreted in urine (21–33%) to a lesser extent than by the i.v. route, and 14CO2 and volatiles accounted for 15–18%. Carbon‐14 recovery was low from tissues and organs (0.39–0.46%), with no preferential accumulation. Extensive metabolism was indicated by the rapid decline in plasma free EGHE, with none being detectable by 48 h. Free EGHE was not present in urine, and urinary radioactivity was associated with up to seven metabolites. After cutaneous dosing of male and female rabbits (10 mg kg−1) ca. 75% of the dose was recovered, most 14C being in urine (58–60%). Urine radioactivity was associated with up to nine metabolite peaks, but no free EGHE. The toxicokinetic ﬁndings indicate a signiﬁcant percutaneous absorption of EGHE across both rat and rabbit skin, which is rapidly and extensively metabolized, with renal excretion being the principal route of elimination of metabolites. A 9‐day repeated skin contact study in the male and female New Zealand White rabbit, using a dosage range of 44–444 mg kg−1 day−1, did not show any evidence for percutaneous systemic toxicity. Copyright © 2003 John Wiley & Sons, Ltd.
Toxicological evaluation of an electrically heated cigarette. Part 3: Genotoxicity and cytotoxicity of mainstream smoke
Authors: Tewes F. J. , Meisgen T. J. , Veltel D. J. , Roemer E. , Patskan G.
Published: September 2003

The in vitro toxicity of cigarette mainstream smoke from an electrically heated cigarette (EHC) with controlled combustion was compared with that of the standard University of Kentucky Reference Cigarette 1R4F.

In the Salmonella reverse mutation assay, strains TA98, TA100, TA102, TA1535 and TA1537 were used in the absence and presence of a metabolic promutagen activation system (S9) to determine the mutagenic potential of the total particulate matter (TPM), which was collected on a glass‐ﬁber ﬁlter. In the neutral red uptake assay, mouse embryo BALB/c 3T3 cells were used to determine the cytotoxic potential of TPM as well as of the water‐solubles in the gas/vapor phase trapped in phosphate‐buffered saline.

The TPM from the electrically heated cigarette was up to 90% lower in mutagenicity than that of the 1R4F calculated on an equal TPM basis. This reduction in mutagenicity is consistent with the signiﬁcantly lower concentration of nearly all constituents analyzed in EHC smoke. With regard to cytotoxicity when calculated on an equal TPM basis, TPM from the electrically heated cigarette was 40% less active relative to the 1R4F. When calculated on a per cigarette basis, the cytotoxicity of both the TPM fraction and the water‐solubles in the gas/vapor phase of smoke from the EHC was ca. 80% lower relative to the 1R4F. Copyright © 2003 John Wiley & Sons, Ltd.
Parabens, oestrogenicity, underarm cosmetics and breast cancer: a perspective on a hypothesis
Authors: Harvey Philip W.
Published: September 2003

A recent review by Darbre (2003) published in this journal (J. Appi. Toxicol. 23: 89–95) has attracted public and scientiﬁc interest that requires perspective, particularly on the use of esters of p‐hydroxybenzoic acid (parabens) as preservatives in underarm cosmetics. Although parabens are generally regarded as safe, recent reports suggest that they are oestrogenic in a variety of in vitro (including MCF7 and ZR‐75‐1 human breast cancer cell lines) and in vivo tests for oestrogenicity (uterotrophic assays in both rat and mouse). There are also recent reports of adverse reproductive and developmental outcomes in rodent toxicity studies. Of interest is the lack of activity by the oral route but clear activity by the subcutaneous and topical routes, which is of some relevance to the use of underarm cosmetics. There would seem to be a case now to supplement these emerging toxicity data with longer term regulatory standard tests examining other oestrogenic endpoints and at least to consider these ﬁndings in more up‐to‐date risk assessments speciﬁc for cosmetic use. Further, there are few data on the use of underarm cosmetics and the risk of breast cancer, and although one recent retrospective interview‐based study found no association there is a need for more thorough investigation taking into account the type of chemicals used. Darbre has forwarded a hypothesis and called for further work to establish whether or not the use of underarm cosmetics (particularly containing oestrogenic formulants) contributes to the rising incidence of breast cancer. It would seem prudent to conduct this work because the current database is sparse and the effects of long‐term low‐level exposures to weakly oestrogenic chemicals on human health, particularly their application to the underarm and the risks of breast cancer, are unknown. The role of oestrogens in breast cancer, however, is undisputed. Copyright © 2003 John Wiley & Sons, Ltd.
Tissue interactions and lens‐forming competence in the outer cornea of larval Xenopus laevis
Authors: Cannata Stefano M. , Arresta Emiliano , Bernardini Sergio , Gargioli Cesare , Filoni Sergio
Published: September 2003

After lentectomy through the pupillary hole, the outer cornea of larval Xenopus laevis can undergo transdifferentiation to regenerate a new lens. This process is elicited by inductive factor(s) produced by the neural retina and accumulated into the vitreous chamber. During embryogenesis, the outer cornea develops from the outer layer of the presumptive lens ectoderm (PLE) under the influence of the eye cup and the lens. In this study, we investigated whether the capacity of the outer cornea to regenerate a lens is the result of early inductive signals causing lens‐forming bias and lens specification of the PLE, or late inductive signals causing cornea formation or both signals. Fragments of larval epidermis or cornea developed from ectoderm that had undergone only one kind of inductive signals, or both kinds of signals, or none of them, were implanted into the vitreous chamber of host larvae. The regeneration potential and the lens‐forming transformations of the implants were tested using an antisense probe for pax6 as an earlier marker of lens formation and a monoclonal antibody anti‐lens as a definitive indicator of lens cell differentiation. Results demonstrated that the capacity of the larval outer cornea to regenerate a lens is the result of both early and late inductive signals and that either early inductive signals alone or late inductive signals alone can elicit this capacity. J. Exp. Zool. 299A:161–171, 2003. © 2003 Wiley‐Liss, Inc.
Teleost Fh14‐3‐3a protein protects xenopus oocytes from hyperosmolality
Authors: Kohn Andrea , Chakravarty Devulapalli , Kültz Dietmar
Published: September 2003

We have previously cloned and characterized a novel 14‐3‐3 gene from the euryhaline telost Fundulus heteroclitus, Fh14‐3‐3a (Kültz et al., 2001). The corresponding gene product is osmoregulated and most highly expressed in gill epithelium of this fish. In the present study we have expressed Fh14‐3‐3a cRNA in Xenopus laevis oocytes and investigated the survival and electrophysiological parameters of Xenopus oocytes in isosmotic and various hyperosmotic media. Xenopus oocytes expressing Fh14‐3‐3a show no mortality after a 16 hour exposure to hyperosmolality in the form of elevating medium K+, Na+, polyethylene glycol, or sorbitol concentrations up to 444 mosmol/kg. In contrast, 16 hours of the same hyperosmolality caused 100% mortality in control Xenopus oocytes injected with water. As a result of hyperosmolality the Xenopus oocyte membrane potential decreased between 10 and 70% in oocytes expressing Fh14‐3‐3a whereas it was completely abolished in control oocytes. We report that one potential cause for the osmoprotective effect of Fh14‐3‐3a on Xenopus oocytes could be its inhibition of an endogenous chloride current. Hyperosmotic urea was not as harmful to Xenopus oocytes as hypertonicity and maybe acting through a different mechanism. Coexpression of Fh14‐3‐3a with a human calcium channel in Xenopus oocytes did not affect the electrophysiological properties of this exogenous channel. Thus, the osmoprotective effect of Fh14‐3‐3a may prove a valuable tool for the characterization of exogenous ion channels in Xenopus oocytes exposed to hyperosmotic conditions. J. Exp. Zool. 299A:103–109, 2003. © 2003 Wiley‐Liss, Inc.
Seasonal reproductive endocrine profile of the raccoon dog (Nyctereutes procyonoides)—effects of melatonin and food deprivation
Authors: Asikainen Juha , Mustonen Anne‐Mari , Hyvärinen Heikki , Nieminen Petteri
Published: September 2003

The raccoon dog (Nyctereutes procyonoides, Canidae, Carnivora) is a middle‐sized omnivore with excessive autumnal fattening and winter sleep. We studied adaptations of the species to boreal climate and photoperiod by following the plasma reproductive and thyroid hormone concentrations of farm‐bred raccoon dogs (n=32) for 12 months. On August 16, 2000, and February 8, 2001, half of the raccoon dogs received continuous‐release melatonin implants (the MEL group). The other half was sham‐operated (the SHAM group). Between November 27, 2000, and January 25, 2001, half of the animals of both groups were fasted. The plasma testosterone concentrations of the MEL males peaked in February, a month earlier than in the SHAM males. Autumnal melatonin treatment also advanced the gestation period reflected by the plasma progesterone concentrations by seven weeks. Food deprivation in winter seems to accentuate the sex steroid response during the mating as the fasted males had higher testosterone concentrations than the fed males in February and March. J. Exp. Zool. 180–187, 2003. © 2003 Wiley‐Liss, Inc.
A partition property of a mixed type for Pκ(λ)
Authors: Matet Pierre
Published: September 2003

Given a regular infinite cardinal κ and a cardinal λ > κ, we study fine ideals H on Pκ(λ) that satisfy the square brackets partition relation $ H^{+} {\mathop \rightarrow \limits^{\kappa}} [H^{+}]^{2}_{\mu} $, where μ is a cardinal ≥2. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Kripke‐style semantics for many‐valued logics
Authors: Montagna Franco , Sacchetti Lorenzo
Published: September 2003

This paper deals with Kripke‐style semantics for many‐valued logics. We introduce various types of Kripke semantics, and we connect them with algebraic semantics. As for modal logics, we relate the axioms of logics extending MTL to properties of the Kripke frames in which they are valid. We show that in the propositional case most logics are complete but not strongly complete with respect to the corresponding class of complete Kripke frames, whereas in the predicate case there are important many‐valued logics like BL, Ł and Π, which are not even complete with respect to the class of all predicate Kripke frames in which they are valid. Thus although very natural, Kripke semantics seems to be slightly less powerful than algebraic semantics. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Global attractor for the semilinear thermoelastic problem
Authors: Gao Hongjun
Published: September 2003

In this paper we consider a class of semilinear thermoelastic problems. The global attractor for this semilinear thermoelastic problem with Dirichlet boundary condition is obtained. Copyright © 2003 John Wiley & Sons, Ltd.
An integral equation solution for three‐dimensional heat extraction from planar fracture in hot dry rock
Authors: Ghassemi A. , Tarasovs S. , H.‐D. Cheng A.
Published: September 2003

In the numerical simulation of heat extraction by circulating water in a fracture embedded in geothermal reservoir, the heat conduction in the reservoir is typically assumed to be one‐dimensional and perpendicular to the fracture in order to avoid the discretization of the three‐dimensional reservoir geometry. In this paper we demonstrate that by utilizing the integral equation formulation with a Green's function, the three‐dimensional heat flow in the reservoir can be modelled without the need of discretizing the reservoir. Numerical results show that the three‐dimensional heat conduction effect can significantly alter the prediction of heat extraction temperature and the reservoir life as compared to its one‐dimensional simplification. Copyright © 2003 John Wiley & Sons, Ltd.
Three‐dimensional elasto‐plastic model for unsaturated compacted soils with different initial densities
Authors: Sun D.A. , Matsuoka H. , Cui H.B. , Xu Y.F.
Published: September 2003

This paper presents an elasto‐plastic model for unsaturated compacted soils and experimental results obtained from a series of suction‐controlled triaxial tests on unsaturated compacted clay with different initial densities. The initial density dependency of the compacted soil behaviour is modelled by establishing experimental relationships between the initial density and the corresponding yield stress and thereby between the initial density and the location and slope of normal compression line. The model is generalized to three‐dimensional stress states by assuming that the shapes of the failure surface and the yield surface in the deviatoric plane are given by the extended SMP criterion. A considerable number of the isotropic compression, triaxial compression and extension tests on unsaturated compacted clay with different initial densities were performed using a suction‐controllable triaxial apparatus, to measure the stress–strain–volume change in different stress paths and wetting paths. The model has well‐predicting capabilities to reproduce the mechanical behaviour of specimens compacted under different conditions not only in isotropic compression but also in triaxial compression and triaxial extension. Copyright © 2003 John Wiley & Sons, Ltd.
Prenatal detection of complex chromosomal aberrations using advanced molecular cytogenetic techniques
Authors: de Pater J. M. , Govaerts L. C. P. , de Man S. A. , van der Sijs‐Bos C. J. M. , Christiaens G. C. M. L. , van Dam W. M. , Loneus W. H. , Engelen J. J. M.
Published: September 2003

Objective

This study aimed to identify a marker chromosome and characterize the short arm of a derivative chromosome 5 in a foetus with the following karyotype: mos 47,XX,del(5)(p?),+i(5)(p10)[50]/48,XX,del(5)(p?),+i(5)(p10),+mar[25].

Method

Amniocentesis was performed in the 26th week of pregnancy because of ultrasound abnormalities (polyhydramnion and decreased amount of gastric filling). All classic banding techniques were performed. FISH and microdissection combined with reverse painting were used to reveal the exact origin of the marker and any extra material on the deleted chromosome 5p.

The parents decided to continue the pregnancy and we compared the clinical features of the child born in week 34 with data from the literature on trisomy 5p. The possible contribution of trisomy of the centromeric region of chromosome 8 and trisomy 8p23.3→8pter to this clinical picture was evaluated.

Results

GTG banding showed one normal and two aberrant chromosomes 5 [del(5)(p?) and i(5)(p10)] in all the cells examined. Furthermore, a supernumerary marker chromosome was present in approximately 30% of the cells. The marker was CBG positive and positive with the pancentromere probe, but dystamicinA/DAPI negative. It did not contain NOR‐positive satellites. FISH proved this marker to be derived from the centromeric region of chromosome 8. MicroFISH disclosed the aberrant chromosome 5 as der(5)t(5;8)(p10;p23.3). The parent's karyotypes were normal.

The baby showed the characteristic features of trisomy 5p syndrome. She died at the age of 15 days after cardiorespiratory arrest.

Conclusion

The karyotype was interpreted as mos 47,XX,add(5)(p10).rev ish der(5)t(5;8)(p10;p23.3),+i(5)(p10) (WCP5+,D5S23+)[50]/48,XX,add(5)(p10).rev ish der(5)t(5;8)(p10;p23.3),+i(5)(p10)(WCP5+,D5S23+),+mar.ish 8(p10q10)(D8Z2+,WCP8‐)[25].

Therefore, the baby had complete trisomy 5p, with trisomy of the distal part of 8p and of the centromeric region of chromosome 8.

The clinical significance of de novo marker chromosomes is a major problem in prenatal counselling. Molecular cytogenetic tools such as FISH and microFISH are indispensable for characterizing markers and determining the breakpoints more precisely in deleted chromosomes. Copyright © 2003 John Wiley & Sons, Ltd.
Prenatal diagnosis of multiple pterygium syndrome associated with Klinefelter syndrome
Authors: Lembet Arda , Oktem Mesut , Yılmaz Zerrin , Kaya Umit , Derbent Murat
Published: September 2003

A nonlethal form of multiple pterygium syndrome (MPS) was diagnosed prenatally at 16 weeks of gestation with associated Klinefelter syndrome in the same fetus. The ultrasound findings were cystic hygroma, hypertelorism, micrognathia, low‐set ears, flexion contractures of upper and lower extremities and rocker‐bottom foot. Genetic amniocentesis revealed a 47,XXY karyotype. After genetic counseling, the parents decided to have a therapeutic abortion. We presented this case for the purpose of further describing the early ultrasound findings and clinical features of multiple pterygium syndromes. Also, what makes our patient unique is the coincidental presence of Klinefelter syndrome with MPS. To our knowledge, this is the first case in the literature in which a 47,XXY karyotype has been found in a fetus with multiple pterygium syndrome. The importance of delineating the exact subtype of MPS and making a precise differential diagnosis becomes critical during the process of evaluation of patients with MPS. Copyright © 2003 John Wiley & Sons, Ltd.
Early prenatal diagnosis of recurrent 46,XY partial gonadal dysgenesis
Authors: Mazza V. , Ottolenghi C. , Di Monte I. , Baldassari F. , Rivasi F. , Volpe A. , Forabosco A.
Published: September 2003

Objectives

We present a case of early prenatal diagnosis of recurrent 46,XY partial gonadal dysgenesis, by combining early genetic and sonographic evaluations.

Methods

The conceptus of a mother with a first child affected by 46,XY gonadal dysgenesis was sonographically evaluated at 21‐ and 23‐mm BPD (12+2 and 12+6 LMP‐based age) and the female genitalia were observed. Karyotype analyses was performed on amniotic fluid and it revealed a 46,XY complement without mosaicism. SRY was amplified by PCR for molecular analyses.

Results

We observed a discordance between female phenotype detected at 21 and 23 mm of biparietal diameter (12+2 and 12+6 LMP‐based age) and male karyotype. In the child and the fetus, seminiferous cords were not recognisable, whereas rare Leydig cells and no germ cells could be identified. Internal and external genitalia were sexually ambiguous in the child and feminized in the fetus.

Conclusion

This is the first case of early prenatal diagnosis of recurrent 46,XY partial gonadal dysgenesis and it points to the importance of combining early analyses of genetic sex with sonography in the management of anomalies of sexual development, with particular regard to syndromes for which the risk of recurrence is little understood. Copyright © 2003 John Wiley & Sons, Ltd.
Severe perinatal hypophosphatasia due to homozygous deletion of T at nucleotide 1559 in the tissue nonspecific alkaline phosphatase gene
Authors: Sawai Hideaki , Kanazawa Nozomi , Tsukahara Yuki , Koike Kazunori , Udagawa Hideo , Koyama Koji , Mornet Etienne
Published: September 2003

Objectives

Hypophosphatasia is an inherited disorder characterized by defective bone mineralization and deficiency of tissue nonspecific alkaline phosphatase (TNSALP) activity. This disorder is caused by various mutations in the TNSALP gene. We report here hypophosphatasia in two siblings, both of them severely affected by the perinatal (lethal) type.

Methods

We diagnosed the first infant by clinical and radiologic manifestations, and laboratory findings. Laboratory findings were characterized by deficiency of serum alkaline phosphatase. Both parents and the second infant were then analyzed by molecular techniques.

Results

The radiograph of the first infant showed severe hypomineralization of the skeleton. Molecular analysis of the second infant showed that this condition was caused by a homozygous single T nucleotide deletion at cDNA number 1559 (1559delT). Both parents were heterozygous carriers for this mutation, although they were not consanguineous.

Conclusion

This mutation has been frequently found in Japanese hypophosphatasia patients, but this is the first observation of a homozygous deletion. This report shows that homozygosity for the 1559delT mutation of the TNSALP gene results in a severe lethal phenotype. Copyright © 2003 John Wiley & Sons, Ltd.
A prokaryotic alternative oxidase present in the bacterium Novosphingobium aromaticivorans
Authors: Stenmark Pål , Nordlund Pär
Published: September 2003

The alternative oxidase (AOX) is a terminal oxidase present in the respiratory chain of all plants as well as some yeasts and trypanosomes, but has not previously been found in a prokaryote. We have identified an AOX homologue in Novosphingobium aromaticivorans, the first AOX found in a prokaryote. We have cloned the gene for the N. aromaticivorans AOX and showed it to have a terminal oxidase activity when heterologously expressed in Escherichia coli. We have also shown that this novel AOX is expressed in N. aromaticivorans cells, and that its expression level is greatly influenced by the oxygen level and carbon source of the growth media.
A numerical model of hydrothermal cooling and crustal accretion at a fast spreading mid‐ocean ridge
Authors: Cherkaoui Abdellah S. M. , Wilcock William S. D. , Dunn Robert A. , Toomey Douglas R.
Published: September 2003

There are two competing models for lower crustal accretion at fast spreading ridges. In the gabbro glacier model, all the lower crust solidifies in a magma lens at the dike/gabbro boundary and then flows to its final level. In the sheeted sill model, the lower crust is formed by sills emplaced at a variety of depths. We present a steady state numerical representation of the sill model that explicitly includes hydrothermal circulation. The crust is accreted uniformly at the ridge axis at all depths and hydrothermal circulation occurs in crustal rocks that have cooled below a threshold temperature. The results show that when the permeability exceeds a threshold value (∼4 × 10−14 m2 for a cracking temperature of 800°C and a uniform permeability), hydrothermal circulation can cool the entire crust near the ridge axis, producing vertical isotherms in the lower crust. At lower permeabilities, the properties of seawater lead to bimodal cooling with the lowermost crust cooling more slowly than shallower depths. These results are reasonably consistent with studies of the seismic structure of the East Pacific Rise and of plagioclase crystal size distributions in gabbros from Oman. We infer that the sheeted sill model cannot be discarded on thermal grounds.
FAST and IMAGE‐FUV observations of a substorm onset
Authors: Mende S. B. , Carlson C. W. , Frey H. U. , Peticolas L. M. , Østgaard N.
Published: September 2003

On 6 February 2002 the NASA FAST satellite transited a substorm break up arc approximately 1 min after substorm onset as identified by the NASA IMAGE satellite far ultraviolet (FUV) instrument complement. These IMAGE data show that both the intense electron and proton precipitation features seen by FAST were not present prior to substorm onset. The most intense onset poleward surge was produced by superthermal electrons, and their energy spectrum and field‐aligned angular distribution were consistent with wave accelerated electrons. The low energy ion fluxes in the E × B direction and magnetometer measurements confirmed the presence of waves in this feature. Thus the leading edge of the auroral surge was not produced by quasi‐static field‐aligned currents and related “inverted V” electric fields. The onset arc was also the poleward boundary of intense energetic protons. The FUV proton auroral images indicate that substantial part of the ion energy was carried by protons of energy >25 keV. Equatorward of the surge, there was a broader region of electron precipitation with embedded quasi‐static “inverted V” electric fields. The FAST particle and magnetometer measurements are consistent with a field‐aligned current structure in which the bulk of the upward current was carried by the “inverted V” precipitation region. The region of the superthermal electrons carried very little net current. The high‐density upward field‐aligned current carried by the superthermal electrons was presumably balanced by oppositely directed downward currents carried by cold electrons. The ground onset location was separated from the closed/open field line boundary by an extended region of closed field lines. In this region there was some weak plasma sheet electron and proton precipitation, but there was no clear signature of any distant, prebreakup substorm onset activity.
Anhydrite precipitation and the relationship between focused and diffuse flow in seafloor hydrothermal systems
Authors: Lowell Robert P. , Yao Yufeng , Germanovich Leonid N.
Published: September 2003

The mechanisms that control the style of high‐temperature hydrothermal discharge at ocean ridge crests are not well understood. Sites of vigorous high‐temperature focused venting are often accompanied by nearby regions of low‐temperature diffuse flow. Moreover, at some sites, high‐temperature fluids are not focused at all and emerge as low‐temperature diffuse flow as a result of conductive cooling and/or mixing with cooler seawater, whereas at others discharge has evolved from low‐temperature diffuse flow to high‐temperature focused flow over a number of years. To better understand the mechanisms that control these discharge styles, we construct a two‐branch single‐pass hydrothermal circulation model to investigate the role of anhydrite precipitation in mixing between deep‐seated, high‐temperature, sulfate‐free upflow and cooler, sulfate‐rich seawater circulating through permeable pillow basalts. We also estimate the width of the impermeable anhydrite barrier between focused and diffuse discharge. The model results suggest that focusing can occur in a matter of years provided the permeability in the deep part of the discharge zone is greater than or equal to that of the mixing zone and the permeability of the mixing zone is initially high (∼10−11–10−12 m2). If one of the previous conditions is not met, only diffuse flow venting will occur. The width of the impermeable barrier resulting from the precipitation of anhydrite ranges between 1 and 100 m, thus permitting diffuse flow to occur in close proximity to focused discharge.
Photochemical and microbial degradation of dissolved lignin phenols: Implications for the fate of terrigenous dissolved organic matter in marine environments
Authors: Hernes Peter J. , Benner Ronald
Published: September 2003

Molecular level characterizations of dissolved lignin were conducted in Mississippi River plume waters to study the impact of various removal mechanisms (photooxidation, microbial degradation, and flocculation) on dissolved organic material (DOM) concentrations and compositions. Prior to analysis, dissolved (<0.2‐μm pore size) samples were size fractionated by ultrafiltration into high molecular weight (HMW; >1 kDalton) and low molecular weight (LMW; <1 kDalton) components. At salinities <25 psu, flocculation and microbial degradation were the primary factors affecting lignin concentrations. At salinities >25 psu, photooxidation was a dominant factor influencing lignin compositions and concentrations. Diagnostic indicators of photooxidation include a sharp decrease in the percentage of lignin in the HMW size fraction, changes in ratios of syringyl to vanillyl phenols, and increases in LMW acid:aldehyde ratios for both vanillyl and syringyl phenols. A 10‐day incubation experiment with plume water indicated rates of microbial degradation of dissolved lignin that were ∼30% of photooxidation rates in surface waters. These results highlight the importance of microbial as well as photochemical processes in the cycling of terrigenous DOM in coastal waters. Neither flocculation nor microbial degradation significantly altered lignin composition, suggesting that composition is primarily determined by source and photochemical transformation. Overall, high removal rates indicate the potential importance of terrigenous DOM as a carbon and nutrient source in the coastal ocean. Strong correlations between absorption coefficients at 350 nm and dissolved lignin demonstrate the potential for using absorption to trace terrigenous DOM in coastal environments with significant riverine input.
Combining altimetric height with broadscale profile data to estimate steric height, heat storage, subsurface temperature, and sea‐surface temperature variability
Authors: Willis Josh K. , Roemmich Dean , Cornuelle Bruce
Published: September 2003

A new technique is demonstrated for combining altimetric height (AH) and sea‐surface temperature (SST) with in situ data to produce improved estimates of 0/800 m steric height (SH), heat content, and temperature variability. The technique uses a linear regression onto AH to construct an initial guess for the subsurface quantity. This guess is then corrected toward the in situ data creating an estimate with substantially less error than could be achieved using either data set alone. Inclusion of the SST data further improves the estimates and illustrates how the procedure can be generalized to allow inclusion of additional data sets. The technique is demonstrated over a region in the southwestern Pacific enclosing the Tasman Sea. Nine‐year time series of heat storage and temperature variability, averaged over 4° latitude and longitude and 1 year in time, are calculated. The estimates have RMS errors of approximately 4.6 W/m2 in heat storage, 0.10°C in subsurface temperature and 0.11°C in surface temperature, and fractional errors of 20, 28, and 18%, respectively, relative to the total variance overall spatial and temporal scales considered. These represent significant improvements over previous estimates of these quantities. All the time series show strong interannual variability including the El Nino event of 1997. Application of these techniques on a global scale could provide new insight into the variability of the general circulation and heat budget of the upper ocean.
Space‐time variability of ozone over the Indian region for the period 1981–1998
Authors: Londhe A. L. , Bhosale C. S. , Kulkarni J. R. , Kumari B. Padma , Jadhav D. B.
Published: September 2003

The space‐time variability of monthly mean total column ozone (TCO) over India has been studied for the period of 18 years from 1981 to 1998. TCO data at four stations, New Delhi (28.31°N, 77.12°E), Varanasi (25.20°N, 83.00°E), Pune (18.31°N, 73.55°E), and Kodaikanal (10.13°N, 77.36°E), Quasi‐Biennial Oscillation (QBO) index data of 30 hPa at Singapore (1°N, 103°E), and F10.7 cm solar flux and Southern Oscillation index data for the above period are used in the study. The effects of the Quasi‐Biennial Oscillation, solar cycle, and volcanic eruptions (El Chichon of 1982, Mount Pinatubo of 1991) on ozone variations have been examined. The multiple regression analysis and singular spectrum analysis of ozone time series (1981–1998) for four stations showed good association between ozone and global forcing parameters, namely QBO and solar cycle. TCO and QBO showed significant negative correlations for New Delhi, Varanasi, and Pune and positive correlation for Kodaikanal. All the stations showed significant positive correlations between TCO and solar flux.
Spectral discrimination of coarse and fine mode optical depth
Authors: O'Neill N. T. , Eck T. F. , Smirnov A. , Holben B. N. , Thulasiraman S.
Published: September 2003

The recognition that the aerosol particle size distribution (PSD) is effectively bimodal permits the extraction of the fine and coarse mode optical depths (τf and τc) from the spectral shape of the total aerosol optical depth (τa = τf + τc). This purely optical technique avoids intermediate computations of the PSD and yields a direct optical output that is commensurate in complexity with the spectral information content of τa. The separation into τf and τc is a robust process and yields aerosol optical statistics, which are more intrinsic than those, obtained from a generic analysis of τa. Partial (optical) validation is provided by (1) demonstrating the physical coherence of the simple model employed, (2) demonstrating that τc variation is coherent with photographic evidence of thin cloud events and that τf variation is coherent with photographic evidence of clear sky and haze events, and (3) showing that the retrieved values of τf and τc are well‐correlated, if weakly biased, relative to formal inversions of combined solar extinction and sky radiance data. The spectral inversion technique permitted a closer scrutiny of a standard (temporally based) cloud‐screening algorithm. Perturbations of monthly or longer‐term statistics associated with passive or active shortcomings of operational cloud screening were inferred to be small to occasionally moderate over a sampling of cases. Diurnal illustrations were given where it was clear that such shortcomings can have a significant impact on the interpretation of specific events; (1) commission errors in τf due to the exclusion of excessively high‐frequency fine mode events and (2) omission errors in τc due to the inclusion of insufficiently high‐frequency thin homogeneous cloud events.
Influence of regional‐scale anthropogenic emissions on CO2 distributions over the western North Pacific
Authors: Vay S. A. , Woo J.‐H. , Anderson B. E. , Thornhill K. L. , Blake D. R. , Westberg D. J. , Kiley C. M. , Avery M. A. , Sachse G. W. , Streets D. G. , Tsutsumi Y. , Nolf S. R.
Published: September 2003

We report here airborne measurements of atmospheric CO2 over the western North Pacific during the March–April 2001 Transport and Chemical Evolution over the Pacific (TRACE‐P) mission. The CO2 spatial distributions were notably influenced by cyclogenesis‐triggered transport of regionally polluted continental air masses. Examination of the CO2 to C2H2/CO ratio indicated rapid outflow of combustion‐related emissions in the free troposphere below 8 km. Although the highest CO2 mixing ratios were measured within the Pacific Rim region, enhancements were also observed further east over the open ocean at locations far removed from surface sources. Near the Asian continent, discrete plumes encountered within the planetary boundary layer contained up to 393 ppmv of CO2. Coincident enhancements in the mixing ratios of C2Cl4, C2H2, and C2H4 measured concurrently revealed combustion and industrial sources. To elucidate the source distributions of CO2, an emissions database for Asia was examined in conjunction with the chemistry and 5‐day backward trajectories that revealed the WNW/W sector of northeast Asia was a major contributor to these pollution events. Comparisons of NOAA/CMDL and JMA surface data with measurements obtained aloft showed a strong latitudinal gradient that peaked between 35° and 40°N. We estimated a net CO2 flux from the Asian continent of approximately 13.93 Tg C day−1 for late winter/early spring with the majority of the export (79%) occurring in the lower free troposphere (2–8 km). The apportionment of the flux between anthropogenic and biospheric sources was estimated at 6.37 Tg C day−1 and 7.56 Tg C day−1, respectively.
Water partitioning at 660 km depth and evidence for very low water solubility in magnesium silicate perovskite
Authors: Bolfan‐Casanova Nathalie , Keppler Hans , Rubie David C.
Published: September 2003

Water partitioning experiments were performed in MgO ± FeO ± Al2O3‐SiO2‐H2O systems at 24 GPa and 1400°C and 1750°C in the multi‐anvil press. In high‐temperature experiments, water was not detected in near‐infrared spectra of perovskite. In samples synthesized at 1400°C, in Al‐free systems, (Mg,Fe)SiO3 perovskite coexisting with hydrous ringwoodite contained 1–2 ppm wt H2O. The partition coefficient Dringwoodite/perovskite of water between perovskite and ringwoodite varies between ∼1050 and 1400. In the presence of aluminium at 1400°C, perovskite coexisted with superhydrous phase B. Raman analysis of the samples reveals the presence of superhydrous phase B and brucite as small inclusions in the perovskite, explaining the peaks near 3690, 3410 and 3350 cm−1, frequently seen in the infrared spectra of aluminous perovskites, but which are absent in perfectly clear regions. Consequently, the water solubility in aluminous perovskite appears to be very low. The partition coefficient Dmagnesiowüstite/perovskite varies between 60 and 75 in Fe‐ and Al‐bearing systems, respectively.
The diamagnetic effect of the equatorial Appleton anomaly: Its characteristics and impact on geomagnetic field modeling
Authors: Lühr H. , Rother M. , Maus S. , Mai W. , Cooke D.
Published: September 2003

The diamagnetic effect generally reduces the magnetic field inside a plasma. Its importance is appreciated in regions like the magnetosphere and the solar wind. In the ionosphere, depletions of the geomagnetic field have up to now been considered negligible. The CHAMP satellite provides for the first time the combination of high‐resolution magnetic field measurements and plasma density observations on the same spacecraft in low‐Earth orbit. We show the typical distribution of electron density at the altitude of about 430 km for various local times. Particularly prominent features are the density enhancements north and south of the dip equator. As expected, the magnetic field intensity is depressed in the crest region by an amount of more than 5 nT. The diamagnetic effect is strongest from sunset to midnight and thus causes errors in global geomagnetic field models which are usually computed from data sampled at all night‐time hours.
Semi‐diurnal and diurnal tidal dissipation from TOPEX/Poseidon altimetry
Authors: Egbert Gary D. , Ray Richard D.
Published: September 2003

Tidal energy dissipation is estimated for eight semi‐diurnal and diurnal constituents using a global inverse solution constrained by TOPEX/Poseidon altimeter data. Very similar spatial patterns are obtained for all semi‐diurnal constituents, with about one third of the total dissipation occurring in the deep ocean over rough topography. Maps for diurnal constituents are also similar amongst themselves, but quite different from the semi‐diurnal results. For diurnals a smaller fraction of dissipation, roughly 10%, occurs in the deep ocean. Much of the difference can be explained by the very different spatial pattern of diurnal and semi‐diurnal tidal currents. The lack of free internal waves at frequencies poleward of 30° at diurnal frequencies also probably plays a role, limiting the effectiveness of baroclinic conversion as an energy sink for barotropic diurnal tides.
The first detection of water absorption on a D type asteroid
Authors: Kanno Ai , Hiroi Takahiro , Nakamura Ryosuke , Abe Masanao , Ishiguro Masateru , Hasegawa Sunao , Miyasaka Seidai , Sekiguchi Tomohiko , Terada Hiroshi , Igarashi George
Published: September 2003

The D type asteroids are among the darkest objects known in our solar system. Here, we present infrared spectra of one of the main‐belt D type asteroids, 773 Irmintraud. In contrast to previous observations of D type asteroids, we found a gap of reflectance around 3 μm in wavelength. The 3 μm gap is one of the spectral signatures of OH or H2O as water ice or in hydrous minerals, which had formed in the processes of aqueous alteration in the early solar system. We suggest that D type asteroids, which are all the while considered as unaltered primitive material, could be aqueously altered. Our data do support the presence of water on a compositionally primitive D type asteroid.
Impacts of Columbia River discharge on salmonid habitat: 2. Changes in shallow‐water habitat
Authors: Kukulka Tobias , Jay David A.
Published: September 2003

This is the second part of an investigation that analyzes human alteration of shallow‐water habitat (SWH) available to juvenile salmonids in the tidal Lower Columbia River. Part 2 develops a one‐dimensional, subtidal river stage model that explains ∼90% of the stage variance in the tidal river. This model and the tidal model developed in part 1 [Kukulka and Jay, 2003] uncouple the nonlinear interaction of river tides and river stage by referring both to external forcing by river discharge, ocean tides, and atmospheric pressure. Applying the two models, daily high‐water levels were predicted for a reach from rkm‐50 to rkm‐90 during 1974 to 1998, the period of contemporary management. Predicted water levels were related to the bathymetry and topography to determine the changes in shallow‐water habitat area (SWHA) caused by flood control dikes and altered flow management. Model results suggest that diking and a >40% reduction of peak flows have reduced SWHA by ∼62% during the crucial spring freshet period during which juvenile salmon use of SWHA is maximal. Taken individually, diking and flow cycle alteration reduced spring freshet SWHA by 52% and 29%, respectively. SWHA has been both displaced to lower elevations and modified in its character because tidal range has increased. Our models of these processes are economical for the very long simulations (seasons to centuries) needed to understand historic changes and climate impacts on SWH. Through analysis of the nonlinear processes controlling surface elevation in a tidal river, we have identified some of the mechanisms that link freshwater discharge to SWH and salmonid survival.