bluuebunny/crossref_metadata_2025 huggingface dataset:
Biochemical, clinical and molecular findings in LCHAD and general mitochondrial trifunctional protein deficiency
Authors: Olpin S. E. , Clark S. , Andresen B. S. , Bischoff C. , Olsen R. K. J. , Gregersen N. , Chakrapani A. , Downing M. , Manning N. J. , Sharrard M. , Bonham J. R. , Muntoni F. , Turnbull D. N. , Pourfarzam M.
Published: May 2005

General mitochondrial trifunctional protein (TFP) deficiency leads to a wide clinical spectrum of disease ranging from severe neonatal/infantile cardiomyopathy and early death to mild chronic progressive sensorimotor poly‐neuropathy with episodic rhabdomyolysis. Isolated long‐chain 3‐hydroxyacyl‐CoA dehydrogenase (LCHAD) deficiency resulting from the common Glu510Gln mutation usually gives rise to a moderately severe phenotype with multiorgan involvement with high morbidity and mortality. However, isolated LCHAD deficiency can also be consistent with long‐term survival in patients identified and treated from an early age. We present biochemical, clinical and mutation data in 9 patients spanning the full spectrum of disease. Fibroblast acylcarnitine profiling shows good correlation with clinical phenotype using the ratio C18(OH)/(C14(OH)+C12(OH)). This ratio shows a gradation of values, from high in four patients with severe neonatal disease (2.5±0.8), to low in two neuromyopathic patients (0.35, 0.2). Fibroblast fatty acid oxidation flux assays also show correlation with the patient phenotype, when expressed either as percentage residual activity with palmitate or as a ratio of percentage activity of myristate/oleate (M/O ratio). Fibroblasts from four patients with severe neonatal disease gave an M/O ratio of 4.0±0.6 compared to 1.97 and 1.62 in two neuromyopathic patients. Specific enzyme assay of LCHAD and long‐chain 3‐ketothiolase activity in patient cells shows lack of correlation with phenotype. These results show that measurements in intact cells, which allow all determinative and modifying cellular factors to be present, better reflect patient phenotype. Mutation analysis reveals a number of α‐ and β‐subunit mutations. Peripheral sensorimotor polyneuropathy, often as the initial major presenting feature but usually later accompanied by episodic rhabdomyolysis, is a manifestation of mild TFP protein deficiency. The mild clinical presentation and relative difficulty in diagnosis suggest that this form of TFP is probably underdiagnosed.
Newborns with C8‐acylcarnitine level over the 90th centile have an increased frequency of the common MCAD 985A>G mutation
Authors: Blois B. , Riddell C. , Dooley K. , Dyack S.
Published: May 2005

Medium chain acyl‐coenzyme A dehydrogenase (MCAD) deficiency is the most commonly inherited defect of fatty acid oxidation. This autosomal recessive disorder is characterized by the tendency to become profoundly hypoglycaemic under fasting stress conditions, leading to lethargy, coma, brain injury and/or death. The most common mutation resulting in MCAD deficiency ascertained through individuals of northern European descent presenting with clinical symptoms is a single base‐pair change (985A>G) that accounts for up to 90% of these abnormal alleles. In the general Nova Scotia population, which comprises largely individuals of northern European descent, this mutation is present at a frequency of 1 in 68. A recently implemented newborn screening programme for MCAD deficiency uses tandem mass spectrometry (MS/MS) to analyse blood spots from newborns for C8‐acylcarnitine. After reviewing initial data from this newborn screening programme, we hypothesized that there was an unexpectedly high frequency of individuals with an MCAD 985A>G mutation and C8‐acylcarnitine levels at the upper end of the normal range. A sample representing the upper 90th centile was screened for the presence of the 985A>Gmutation and 61 heterozygotes were identified, establishing a high frequency (1/10) of this 985A>G mutation in this selected population. We have demonstrated a relationship between heterozygosity for 985A>G and C8‐acylcarnitine levels. These results contribute to the interpretation of C8‐acylcarnitine levels and the establishment of a more clinically relevant screening cut‐off point.
Impaired myocardial perfusion reserve but preserved peripheral endothelial function in patients with Fabry disease
Authors: Kalliokoski R. J. , Kalliokoski K. K. , Sundell J. , Engblom E. , Penttinen M. , Kantola I. , Raitakari O. T. , Knuuti J. , Nuutila P.
Published: May 2005

Fabry disease (McKusick 301500) is an X‐linked lysosomal storage disorder due to deficient α‐galactosidase A activity, which leads to accumulation of glycosphingolipids, especially in vascular smooth‐muscle and endothelial cells. The effect of this accumulation on peripheral and cardiac vascular function is poorly known. We studied 15 Fabry patients (mean age 35 years and mean BMI 24.8 kg/m2) and 30 age‐ and BMI‐matched healthy controls to examine whether myocardial perfusion reserve and peripheral artery endothelial function are altered. Myocardial perfusion was measured at rest and during dipyridamole‐induced hyperaemia by positron emission tomography and H215O. Myocardial blood flow reserve was calculated as the ratio between the dipyridamole‐induced maximal blood flow and resting blood flow. Peripheral artery endothelial function was assessed by measuring the brachial artery flow‐mediated dilatation using ultrasound at rest and during reactive hyperaemia. The myocardial perfusion reserve was significantly lower in Fabry patients than in controls (3.3 ± 1.2 vs 4.4 ± 1.6, p = 0.02), while the brachial artery flow‐mediated dilatation was similar (5.9% ± 3.9%vs 4.5% ± 3.6%, p = 0.27). Thus, inFabry disease, myocardial perfusion reserve is reduced while the peripheral artery endothelial function is preserved.
Enzyme replacement therapy in Japanese Fabry disease patients: The results of a phase 2 bridging study
Authors: Eto Y. , Ohashi T. , Utsunomiya Y. , Fujiwara M. , Mizuno A. , Inui K. , Sakai N. , Kitagawa T. , Suzuki Y. , Mochizuki S. , Kawakami M. , Hosoya T. , Owada M. , Sakuraba H. , Saito H.
Published: May 2005

Fabry Disease (α‐galactosidase A deficiency) is an X‐linked hereditary disorder leading to the pathological accumulation of globotriaosylceramide (GL‐3) in lysosomes, particularly in the vascular endothelium of the kidney, heart and brain. We report the results of an open‐label phase 2 study that was undertaken to evaluate whether ethnic differences exist that would affect agalsidase beta (Fabrazyme) treatment of Fabry patients in the Japanese population, relative to safety and efficacy. The study design mirrored the design of the completed phase 3 clinical trial that led to approval of the product agalsidase beta. The 13 Japanese, male Fabry patients enrolled in the study received the enzyme replacement therapy over a period of 20 weeks as biweekly infusions. All selected efficacy end points showed improvements that were comparable with findings from the phase 3 study. These improvements included reductions of GL‐3 accumulation in both kidney and skin capillary endothelial cells to (near) normal levels (92% of patients). Kidney and plasma GL‐3 levels decreased by 51.9% and 100%, respectively, by ELISA. Renal function remained normal. Fabry‐associated pain, and quality of life, showed improvement over baseline in multiple categories. Related adverse events were mild or moderate in intensity and mostly infusion‐associated (fever and rigors). As expected, IgG antibody formation was observed in 85% of the patients, but had no effect on treatment response. These results suggest that treatment with agalsidase beta is safe and effective in Japanese patients with Fabry disease. With regard to safety and efficacy, no differences were observed as compared to the caucasian population.
Early diagnosis of mucopolysaccharidosis III A with a nonsense mutation and two de novo missense mutations in SGSH gene
Authors: Bekri S. , Armana G. , Ricaud D. De , Osenda M. , Maire I. , Obberghen E. Van , Froissart R.
Published: May 2005

An early presentation of heparan N‐sulphatase (SGSH) deficiency (mucopolysaccharidosis IIIA, MPS IIIA) with a prominent and isolated hepato‐splenomegaly is described. Molecular analysis detected a nonsense mutation (Y40X) and two de novo missense mutations (E300V; Q307P).
Clinical response to sildenafil in pulmonary hypertension associated with Gaucher disease
Authors: Fernandes C. J. C. , Jardim C. , Carvalho L. A. S. , Farias A. Q. , Filho M. Terra , Souza R.
Published: May 2005

There are few reports of pulmonary hypertension in Gaucher disease. We report a patient who showed significant clinical improvement after treatment with sildenafil.
Absolute configuration of N‐acetylaspartate in urine from patients with Canavan disease
Authors: Bal D. , Gryff‐Keller A. , Gradowska W.
Published: May 2005

High‐resolution 1H and 13C NMR of N‐acetylaspartic acid as its 2‐(S)‐butyl diester allows the two enantiomers to be unambiguously identified. Analysis of urine samples from five patients with Canavan disease (N‐aspartoacylase deficiency) showed that more than 95% of the excreted N‐acetylaspartate had the S‐configuration.
Additions to the genus Mycobilimbia s. lat. from the Southern Hemisphere
Authors: KANTVILAS Gintaras , MESSUTI María Inés , LUMBSCH H. Thorsten
Published: May 2005

Two new species of Mycobilimbia are described and compared with other members of the genus: Mycobilimbia australis Kantvilas & Messuti from austral, cool to cold temperate regions, and Mycobilimbia meridionalis Kantvilas from Tasmania. Two additional, superficially similar species that are widespread in the Northern Hemisphere, M. hypnorum (Lib.) Kalb & Hafellner and Bilimbia lobulata (Sommerf.) Hafellner & Coppins, are recorded from Tasmania for the first time.
Notes on Halecania species, with descriptions of two new species from Asia
Authors: van den BOOM Pieter P. G. , ELIX John A.
Published: May 2005

Two species of Halecania from Asia, H. lobulata van den Boom & Elix and H. pakistanica van den Boom & Elix are described as new to science. In addition, the new combination Halecania pepegospora (H. Magn.) van den Boom is made. The ecology, distribution and chemistry of some selected species are discussed and a key to the fifteen species known worldwide is given.
Morphology, chemistry and distribution of Melanelia sorediella (Parmeliaceae) and similar species in the Iberian Peninsula
Authors: RICO Víctor J. , van den BOOM Pieter P. G. , BARRASA José María
Published: May 2005

Lichen material from the Iberian Peninsula of Melanelia commixta, M. hepatizon and M. sorediella has been studied and compared on the basis of morphology, chemistry, habitat and distribution. The new combination Melanelia sorediella is proposed and Cetraria commixta f. sorediella is lectotypified. Chemotypes I and III have been detected in M. commixta. Melanelia sorediella is characterized mainly by the formation of pycnoisidia and soralia-like structures in the lamina and margins of the thallus and by the absence of pseudocyphellae and apothecia. The pycnoisidium is here described as a combination of isidia-like proliferations of the thallus surface containing pycnidia, carrying algae and acting as vegetative symbiotic propagules. Non detached pycnoisidia grow into lobuli in central parts of the thallus, regenerating it. Pycnoisidia, soralia-like areas and lobuli are formed as a consequence of pycnidia development. Melanelia sorediella is morphologically and chemically close to M. commixta and is currently known from mountains of central and south-west Europe where it grows on acid rocks. In south-western Europe, the meridional limit of the distribution of the three species studied seems to be located in the mountains of the central part of the Iberian Peninsula (Sistema Central Ibérico). Relevant data on the three species are provided and a key is also included.
Monodictys epilepraria, a new species of lichenicolous hyphomycetes on Lepraria
Authors: KUKWA Martin , DIEDERICH Paul
Published: May 2005

The new lichenicolous hyphomycete, Monodictys epilepraria, is described from thalli of several Lepraria species. It is known from the Czech Republic, Great Britain, Lithuania, Poland, Spain and Sweden, and appears to be widespread, but probably much overlooked. The new species is characterized by relatively small, brown, muriform, smooth-walled conidia developing on decolourized patches of the host.
Stirtoniella, a new genus for Catillaria kelica (Lecanorales: Ramalinaceae)
Authors: GALLOWAY David J. , HAFELLNER Josef , ELIX John A.
Published: May 2005

Lecidea kelica Stirt., formerly accepted as a corticolous species of Catillaria is shown to belong to a new, monospecific genus here described as Stirtoniella in the family Ramalinaceae. Details of Stirtoniellia kelica, its synonymy, chemistry, ecology and distribution are presented. It is known from New Zealand and Tasmania.
Heppia arenacea and Lempholemma polycarpum, two new species from southern Yemen and Socotra
Authors: SCHULTZ M.
Published: May 2005

Heppia arenacea M. Schultz and Lempholemma polycarpum M. Schultz are described as new and placed in the Lichinaceae. Heppia arenacea occurs in soil-crust communities in southern Yemen and on Socotra. It colonizes both calcareous soil-crusts over limestone as well as soils originating from basaltic rocks. The sand-coloured, squamulose thallus, the erumpent, dark red apothecia and the incorporation of soil material into the thallus are diagnostic characters. Lempholemma polycarpum occurs on inclined limestone boulders in south-eastern Yemen. It is characterized by an umbilicate-lobate thallus with radiating, tongue-shaped, furcate lobes which bear numerous, small, immersed apothecia with punctiform discs.
The first lichen-forming species of Psammina, P. palmata sp. nov., with notes on the status of Cheiromycina and Pycnopsammina
Authors: EARLAND-BENNETT Peter M. , HAWKSWORTH David L.
Published: May 2005

The first lichen-forming species of Psammina, P. palmata sp. nov., is described from decorticate oak in West Suffolk (UK). It is distinguished from other species by the palmate and 2–3-order branched non-septate conidia flattened in a single plane. The conidia recall those of the lichen-forming hyphomycete genus Cheiromycina in some respects, but do not originate from the swollen subglobose cells characteristic of that genus. The generic concepts in this complex of algicolous, lichen-forming, lichenicolous, and saprobic fungi are discussed, and it is concluded that Pycnopsammina should be treated as a synonym of Psammina as the conidiogenesis resembles that of the type species of Psammina, which also has rather similar conidiomata; the combination Psammina lobariae comb. nov. (syn. Pycnopsammina lobariae) is therefore made. A key to the eight species now accepted in the genus is provided, which now includes algicolous, lichen-forming, lichenicolous, and plant saprobic species.
Molecular characterization of the kinetoplastid membrane protein-11 genes from the parasiteTrypanosoma rangeli
Authors: DIEZ H. , THOMAS M. C. , URUEÑA C. P. , SANTANDER S. P. , CUERVO C. L. , LÓPEZ M. C. , PUERTA C. J.
Published: May 2005

Trypanosomatids are early divergent parasites which include several species of medical interest.Trypanosoma rangeliis not pathogenic for humans but shows a high immunological cross-reactivity withTrypanosoma cruzi, the causative agent of Chagas' disease that affects more than 17 million people throughout the world. Recent studies have suggested thatT. cruziKMP-11 antigen could be a good candidate for the induction of immunoprotective cytotoxic responses againstT. cruzinatural infection. In the present paper the genes coding for theT. rangelikinetoplastid membrane protein-11 have been characterized. The results show that the locus encoding this protein is formed by 4 gene units measuring 550 nucleotides in length, organized in tandem, and located in different chromosomes in KP1(+) and KP1(−) strains. The gene units are transcribed as a single mRNA of 530 nucleotides in length. Alignment of theT. rangeliKMP-11 deduced amino acid sequence with the homologous KMP-11 protein fromT. cruzirevealed an identity of 97%. Interestingly, the T and B cell epitopes of theT. cruziKMP-11 protein are conserved in theT. rangeliKMP-11 amino acid sequence.
Culture of Neospora caninum in the presence of a Mycoplasma Removal Agent results in the selection of a mutant population of tachyzoites
Authors: HUDSON A. , ELLIS J. T.
Published: May 2005

Mycoplasmas are common contaminants of eukaryotic cells grown in tissue culture. A commercially available Mycoplasma Removal Agent (MRA) was therefore assessed for its effect on tachyzoites of Neospora caninum, in order to determine its suitability for further use in parasite cell cultures. Analyses of tachyzoite and excreted-secreted proteins and antigens by SDS-PAGE and Western blotting show that MRA treatment results in the rapid selection of a mutant population that differs from the control and parental lines in its protein and antigen content. The treatment of N. caninum cultures with MRA is therefore not recommended for the eradication of Mycoplasma.
Epidemiology ofAnguillicola crassusin the European eel (Anguilla anguilla) from two rivers in southern England
Authors: NORTON J. , ROLLINSON D. , LEWIS J. W.
Published: May 2005

European eelsAnguilla anguillafrom the rivers Thames and Test, in the south of England, were examined between 2000 and 2003 for infection with the swim-bladder nematodeAnguillicola crassus. Since its introduction to Thames eels at tidal estuarine locations circa 1987,A. crassushas become established in non-tidal freshwater stretches upriver and data from these locations are reported for the first time. The prevalence of infection at Thames estuary locations was higher during 2000–2003 than for the period 1987–1992. By 2003, similar prevalences were observed at freshwater and estuarine locations, but infection intensities were significantly higher in freshwater. Eels from the river Test appear to have been recently colonized byA. crassus(circa 2000). Parasite population establishment within these eels was uncharacteristically slow during 2000–2001, with low prevalence and intensity of infection, and few gravid females during this period. By 2003, infection levels in Test eels were similar to those in Thames eels. The expansion of theA. crassuspopulation in Test eels has occurred in the absence of the paratenic host ruffeGymnocephalus cernuus, and at suboptimal pH for the survival and infectivity of free-living larvae. The epidemiology ofA. crassusin Test eels demonstrates that transmission ofA. crassusby ruffe is not required for high prevalence and intensity of infection in eels. However, the consistently low and atypical levels of infection in Test eels during 2000 and 2001 suggests that paratenic transmission by ruffe may provide a substantial contribution to the dynamics ofA. crassusin eels in the early years following introduction, by facilitating the rapid increase in prevalence and intensity ofA. crassusinfection that typically occurs during this time.
Disruption of a host-parasite system following the introduction of an exotic host species
Authors: TELFER S. , BOWN K. J. , SEKULES R. , BEGON M. , HAYDEN T. , BIRTLES R.
Published: May 2005

The potential of biological invasions to threaten native ecosystems is well recognized. Here we describe how an introduced species impacts on native host-parasite dynamics by acting as an alternative host. By sampling sites across an invasion front in Ireland, we quantified the influence of the introduced bank vole (Clethrionomys glareolus) on the epidemiology of infections caused by flea-transmitted haemoparasites of the genusBartonellain native wood mice (Apodemus sylvaticus).Bartonellainfections were detected on either side of the front but occurred exclusively in wood mice, despite being highly prevalent in both rodent species elsewhere in Europe. Bank vole introduction has, however, affected the wood mouse-Bartonellainteraction, with the infection prevalence of bothBartonella birtlesiiandBartonella tayloriideclining significantly with increasing bank vole density. Whilst flea prevalence in wood mice increases with wood mouse density in areas without bank voles, no such relationship is detected in invaded areas. The results are consistent with the dilution effect hypothesis. This predicts that for vector-transmitted parasites, the presence of less competent host species may reduce infection prevalence in the principal host. In addition we found a negative relationship betweenB. birtlesiiandB. tayloriiprevalences, indicating that these two microparasites may compete within hosts.
The impact of host starvation on parasite development and population dynamics in an intestinal trypanosome parasite of bumble bees
Authors: LOGAN A. , RUIZ-GONZÁLEZ M. X. , BROWN M. J. F.
Published: May 2005

Host nutrition plays an important role in determining the development and success of parasitic infections. While studies of vertebrate hosts are accumulating, little is known about how host nutrition affects parasites of invertebrate hosts.Crithidia bombiis a gut trypanosome parasite of the bumble bee,Bombus terrestrisand here we use it as a model system to determine the impact of host nutrition on the population dynamics and development of micro-parasites in invertebrates. Pollen-starved bees supported significantly smaller populations of the parasite. In pollen-fed bees the parasite showed a temporal pattern in development, with promastigote transmission stages appearing at the start of the infection and gradually being replaced by choanomastigote and amastigote forms. In pollen-starved bees this developmental process was disrupted, and there was no pattern in the appearance of these three forms. We discuss the implications of these results for parasite transmission, and speculate about the mechanisms behind these changes.
Relationships between generations in post-Emancipation Lithuania (1864–1904)
Authors: PILINKAITE-SOTIROVIC VILANA
Published: May 2005

One of the most powerful influences on modern peasant studies has been Chayanov's notion that the peasant farm household balanced the labour efforts of a household and its consumer demands. As a result, peasant households have been seen as autarchic units of production and consumption, and peasant strategies were held to be designed to preserve the common enterprise in which everyone was expected to work and pool resources, and to maintain the integrity of the original holding, of which all family members were expected to receive an equal share. This article focuses on familial strategies of Lithuanian peasants after the abolition of serfdom in the second half of the nineteenth century and argues that the strategies of different generations were shaped by a multiplicity of dependencies, a constant reshuffle of resources and the maximum utilization of land and labour. Examination of the pattern of generational turnover and of the working arrangements between parents and adult children suggests that relationships between the generations were built on reciprocity and that co-operation or some other mutual help was essential in the post-emancipation village.
When there was no male heir: the transfer of wealth through women in Catalonia (the pubilla)
Authors: FERRER ALÒS LLORENÇ
Published: May 2005

In Catalonia the hereditary system envisaged that the eldest son in the family would inherit. When there was no male heir, the oldest daughter would inherit, and was then called the pubilla. This circumstance allowed the possibility of an heir and an heiress marrying, which would result in the unification of their patrimonies. According to traditional historiography, this was one explanation of the concentration of rural patrimonies. This article demonstrates that the heir–heiress wedding was not the most often chosen scenario, however, and looks again at the options that families had to consider, according to their circumstances, when a daughter was the heir, and at the results of their choices.
Qp structure of Mount Etna: Constraints for the physics of the plumbing system
Authors: De Gori P. , Chiarabba C. , Patanè D.
Published: May 2005

In this study we present the three‐dimensional Qp structure of the Mount Etna volcano (Italy), obtained by using local earthquake data. The attenuation along ray paths (t*), computed from the high‐frequency decay of velocity spectra, is used to reconstruct the deep structure of the volcano down to 15 km depth. The tomographic images reveal two broad low‐Qp anomalies at 0 and 3 km depth, located to the south and southwest of the summit area and extending at depth to the west of a central high‐Qp anomaly located between 6 and 15 km depth. The joint analysis of P wave attenuation and velocity allows us to better constrain the physics of the plumbing system. The shallow low‐Qp anomalies are associated with high‐Vp anomalies beneath the top of the volcano and normal low Vp toward its western borders. We interpret the regions of low Qp and normal‐low Vp as shallow volumes where magmatic fluids are stored. Conversely, the low‐Qp, high‐Vp region may indicate intensely fractured rock volumes filled by fluids surrounding the magma branches. At depth, the low‐Qp anomaly defines the path of the magma ascent to the west of an extremely high‐Qp, high‐Vp volume located beneath the southeastern side of the summit area. The high‐Qp, high‐Vp body is interpreted to be the compact, solidified, high‐density intrusive body formed by nonerupted material during past volcano activity.
High‐resolution measurement of the seismic attenuation across the Vrancea region, Romania
Authors: Sudhaus H. , Ritter J. R. R.
Published: May 2005

We use teleseismic waveforms from a seismic refraction experiment along a N‐S profile across the Vrancea region, Romania, to study seismic attenuation. This unique data set with an average station spacing of about 2–3 km provides spatial high‐resolution estimates of the variability in seismic attenuation. Time windows of the analyzed seismic phases are extracted with a multiple‐taper technique and spectral ratios (δt*) are determined. Our results from 4 teleseismic phases (P, pP, PKPdf, and PP) of two events underneath Hokkaido, Japan and New Guinea find a significant variation of the seismic attenuation along the line. A major influence of local site effects on the values of δt* can be excluded as well as a correlation with the Vrancea slab. The variations of the δt* operators from different phases at individual stations seem to be caused by the projection of three‐dimensional attenuating structures at deep lithospheric levels.
VHF radar observations of weak echo regions in tropical mesoscale convective systems
Authors: Kumar Karanam Kishore , Joseph JoJo , Jain A. R. , Rao D. Narayana
Published: May 2005

A multibeam VHF radar experiment, which was carried out to explore the mesoscale convective systems over Gadanki (13.5°N, 79.2°E), is discussed. These observations revealed an interesting pattern in the height horizontal distance section of radar reflectivity. A weak echo region (WER) is observed in the height region of ∼8–14 km well above the melting layer, which is believed to be first of its kind in VHF radar observations. A single vertical velocity core of ∼7 km vertical extent with ∼10 ms−1 vertical velocity is observed and it has been noticed that the WER is forming in the peripheral region of large vertical velocities. An attempt has been made to explain the plausible mechanism responsible for the formation of WERs. Significance of present results lies in showing the capability of VHF radar to scan the convective system in vertical plane and in providing observational evidence for existence of WER above the melting level.
Improved ionospheric electrodynamic models and application to calculating Joule heating rates
Authors: Weimer D. R.
Published: May 2005

Improved techniques have been developed for empirical modeling of the high‐latitude electric potentials and magnetic field‐aligned currents (FAC) as a function of the solar wind parameters. The FAC model is constructed using scalar magnetic Euler potentials and functions as a twin to the electric potential model. The improved models have more accurate field values plus more accurate boundary locations. Nonlinear saturation effects in the solar wind–magnetosphere coupling are also better reproduced. The models are constructed using a hybrid technique, which has spherical harmonic functions only within a small area at the pole. At lower latitudes the potentials are constructed from multiple Fourier series functions of longitude at discrete latitudinal steps. It is shown that the magnetic (FAC) and electric potential models can be used together to calculate the total Poynting flux and Joule heating in the ionosphere. An additional model of the ionospheric conductivity is not required to obtain the ionospheric currents and Joule heating, as the conductivity variations as a function of the solar inclination are implicitly contained within the FAC model's data. The models' outputs are shown for various input conditions and are also compared with satellite measurements. The calculations of the total Joule heating are compared with results obtained by the inversion of ground‐based magnetometer measurements. Like their predecessors, these empirical models should continue to be useful research and forecast tools.
North American pollution outflow and the trapping of convectively lifted pollution by upper‐level anticyclone
Authors: Li Qinbin , Jacob Daniel J. , Park Rokjin , Wang Yuxuan , Heald Colette L. , Hudman Rynda , Yantosca Robert M. , Martin Randall V. , Evans Mathew
Published: May 2005

We examine the major outflow pathways for North American pollution to the Atlantic in summer by conducting a 4‐year simulation with the GEOS‐CHEM global chemical transport model, including a coupled ozone‐aerosol simulation with 1° × 1° horizontal resolution for summer 2000. The outflow is driven principally by cyclones tracking eastward across North America at 45–55°N, every 5 days on average. Anthropogenic and fire effluents from western North America are mostly transported north and east, eventually merging with the eastern U.S. pollution outflow to the Atlantic. A semipermanent upper‐level anticyclone traps the convective outflow and allows it to age in the upper troposphere over the United States for several days. Rapid ozone production takes place in this outflow, driven in part by anthropogenic and lightning NOx and in part by HOx radicals produced from convectively lifted CH2O that originates from biogenic isoprene. This mechanism could explain ozonesonde observations of elevated ozone in the upper troposphere over the southeastern United States. Asian and European pollution influences in the North American outflow to the Atlantic are found to be dispersed into the background and do not generate distinct plumes. Satellite observations of CO columns from MOPITT and of aerosol optical depths (AODs) from MODIS provide useful mapping of outflow events, despite their restriction to clear‐sky scenes.
A microphysical parameterization for convective clouds in the ECHAM5 climate model: Single‐column model results evaluated at the Oklahoma Atmospheric Radiation Measurement Program site
Authors: Zhang Junhua , Lohmann Ulrike , Stier Philip
Published: May 2005

The microphysical parameterization used for stratiform clouds in the ECHAM5 climate model is now extended for simulations of convective clouds. The performance of the newly implemented parameterization in simulating midlatitude continental summertime convective cloud systems is evaluated in this paper at the Atmospheric Radiation Measurement Program (ARM) Southern Great Plains (SGP) site in Oklahoma using the single‐column mode (SCM) of ECHAM5. Three ARM intensive operating periods (IOPs), including two summer ones and a late spring one, are used for the evaluation. Results show that the SCM simulated cloud cover fraction agrees well with observations. The SCM also captures most of the precipitation events. With the new microphysical parameterization, the model performs at least as well as with the original model setup in simulating almost all the fields examined in this study. Significant improvement is shown in the simulations of outgoing longwave radiation and net incoming solar radiation at the top of the atmosphere revealing the feasibility of the new parameterization. Sensitivity studies show that a 10‐fold increase in cloud droplet number concentration significantly increases the simulated liquid water content. More interestingly, this increase in cloud droplet number leads to an increase in the total amount of precipitation in two of the three IOPs.
Statistical properties of the normalized ice particle size distribution
Authors: Delanoë Julien , Protat Alain , Testud Jacques , Bouniol Dominique , Heymsfield A. J. , Bansemer A. , Brown P. R. A. , Forbes R. M.
Published: May 2005

Testud et al. (2001) have recently developed a formalism, known as the “normalized particle size distribution (PSD)”, which consists in scaling the diameter and concentration axes in such a way that the normalized PSDs are independent of water content and mean volume‐weighted diameter. In this paper we investigate the statistical properties of the normalized PSD for the particular case of ice clouds, which are known to play a crucial role in the Earth's radiation balance. To do so, an extensive database of airborne in situ microphysical measurements has been constructed. A remarkable stability in shape of the normalized PSD is obtained. The impact of using a single analytical shape to represent all PSDs in the database is estimated through an error analysis on the instrumental (radar reflectivity and attenuation) and cloud (ice water content, effective radius, terminal fall velocity of ice crystals, visible extinction) properties. This resulted in a roughly unbiased estimate of the instrumental and cloud parameters, with small standard deviations ranging from 5 to 12%. This error is found to be roughly independent of the temperature range. This stability in shape and its single analytical approximation implies that two parameters are now sufficient to describe any normalized PSD in ice clouds: the intercept parameter N*0 and the mean volume‐weighted diameter Dm. Statistical relationships (parameterizations) between N*0 and Dm have then been evaluated in order to reduce again the number of unknowns. It has been shown that a parameterization of N*0 and Dm by temperature could not be envisaged to retrieve the cloud parameters. Nevertheless, Dm‐T and mean maximum dimension diameter ‐T parameterizations have been derived and compared to the parameterization of Kristjánsson et al. (2000) currently used to characterize particle size in climate models. The new parameterization generally produces larger particle sizes at any temperature than the Kristjánsson et al. (2000) parameterization. These new parameterizations are believed to better represent particle size at global scale, owing to a better representativity of the in situ microphysical database used to derive it. We then evaluated the potential of a direct N*0‐Dm relationship. While the model parameterized by temperature produces strong errors on the cloud parameters, the N*0‐Dm model parameterized by radar reflectivity produces accurate cloud parameters (less than 3% bias and 16% standard deviation). This result implies that the cloud parameters can be estimated from the estimate of only one parameter of the normalized PSD (N*0 or Dm) and a radar reflectivity measurement.
Seasonal variations of the Na and Fe layers at the South Pole and their implications for the chemistry and general circulation of the polar mesosphere
Authors: Gardner Chester S. , Plane John M. C. , Pan Weilin , Vondrak Tomas , Murray Benjamin J. , Chu Xinzhao
Published: May 2005

Lidar observations, conducted at the South Pole by University of Illinois researchers, are used to characterize the seasonal variations of mesospheric Na and Fe above the site. The annual mean layer abundances are virtually identical to midlatitude values, and the mean centroid height is just 100 m higher for Na and 450 m higher for Fe compared with 40°N. The most striking feature of the metal profiles is the almost complete absence of Na and Fe below 90 km during midsummer. This leads to summertime layers with significantly higher peaks, narrower widths, and smaller abundances than are observed at lower latitudes. The measurements are compared with detailed chemical models of these species that were developed at the University of East Anglia. The models accurately reproduce most features of these observations and demonstrate the importance of rapid uptake of the metallic species on the surfaces of polar mesospheric clouds and meteoric smoke particles. The models show that vertical downwelling in winter, associated with the meridional circulation system, must be less than about 1 cm s−1 in the upper mesosphere in order to avoid displacing the minor constituents O, H, and the metal layers too far below 85 km. They also show that an additional source of gas‐phase metallic species, that is comparable to the meteoric input, is required during winter to correctly model the Na and Fe abundances. This source appears to arise from the wintertime convergence of the meridional flow over the South Pole.
Pitted cones and domes on Mars: Observations in Acidalia Planitia and Cydonia Mensae using MOC, THEMIS, and TES data
Authors: Farrand William H. , Gaddis Lisa R. , Keszthelyi Laszlo
Published: May 2005

Domes and cones with summit pits located in Acidalia Planitia and Cydonia Mensae were studied using MOC and THEMIS images and a TES‐derived thermal inertia map. North of 40.5°N latitude, the features have a dome‐like morphology, and south of that latitude, the morphology is more cone‐like. Layering is apparent in the summit craters of fresher looking southern cones, and asymmetric aprons were observed in some instances. Some of the northern domes also display layering in their summit craters, but asymmetric aprons were not observed. The northern domes can also display multiple summit pits or no summit pits at all and can occur in association with higher‐albedo “pancake” features. The northern domes are higher in albedo but have apparent thermal inertias that are lower than the surrounding plains. The apparent thermal inertia values of the southern cones range from values comparable to the surrounding plains to slightly lower. From the TES thermal inertia map, we infer that the thermal inertia values of the pitted cones are between those of basaltic fine dust and sand, while those of the surrounding plains are closer to that of basaltic sand. While a unique interpretation of the origin of the pitted cones is not possible with the available data, we do not find compelling evidence to suggest an origin related to either basaltic volcanism or ground‐ice. Instead, an origin for these features through some combination of mud volcanism and evaporite deposition around geysers and/or springs is most consistent with the observations.
Optimizing water supply headworks operating rules under stochastic inputs: Assessment of genetic algorithm performance
Authors: Cui Lijie , Kuczera George
Published: May 2005

Realistic optimization of the operation of urban water supply headworks systems requires that the issues of system complexity and stochasticity be addressed. A promising way of achieving this is to couple probabilistic search methods such as genetic algorithms (GAs) with Monte Carlo simulation models. However, the objective function surface, characteristic of this genre of problem, exhibits piecewise flat regions separated by steep slopes. The size of these flat regions is affected by the frequency of droughts sampled in the Monte Carlo simulation. Although an earlier study proposed a GA variant that appears to robustly negotiate such objective function surfaces, the assessment was limited to a simple one‐reservoir system. There remains therefore a legitimate concern that for more complex systems the GA may converge prematurely producing decisions of little practical value. This study assesses the ability of the GA to optimize key operating rules for a complex urban headworks system with nine reservoirs and interbasin transfers subject to a highly variable climate. Eight decisions affecting restriction rules, pump marks, and contingent desalination were optimized using an objective function that minimized expected annual costs. It is shown that the GA produced results that are judged consistent with the strategy that minimizes total expected costs. In addition, the sensitivity of the GA results to the length of the Monte Carlo simulation was investigated.
Uncertainty assessment of hydrologic model states and parameters: Sequential data assimilation using the particle filter
Authors: Moradkhani Hamid , Hsu Kuo‐Lin , Gupta Hoshin , Sorooshian Soroosh
Published: May 2005

Two elementary issues in contemporary Earth system science and engineering are (1) the specification of model parameter values which characterize a system and (2) the estimation of state variables which express the system dynamic. This paper explores a novel sequential hydrologic data assimilation approach for estimating model parameters and state variables using particle filters (PFs). PFs have their origin in Bayesian estimation. Methods for batch calibration, despite major recent advances, appear to lack the flexibility required to treat uncertainties in the current system as new information is received. Methods based on sequential Bayesian estimation seem better able to take advantage of the temporal organization and structure of information, so that better compliance of the model output with observations can be achieved. Such methods provide platforms for improved uncertainty assessment and estimation of hydrologic model components, by providing more complete and accurate representations of the forecast and analysis probability distributions. This paper introduces particle filtering as a sequential Bayesian filtering having features that represent the full probability distribution of predictive uncertainties. Particle filters have, so far, generally been used to recursively estimate the posterior distribution of the model state; this paper investigates their applicability to the approximation of the posterior distribution of parameters. The capability and usefulness of particle filters for adaptive inference of the joint posterior distribution of the parameters and state variables are illustrated via two case studies using a parsimonious conceptual hydrologic model.
Dispersion, scale, and time dependence of mixing zones under gravitationally stable and unstable displacements in porous media
Authors: Menand T. , Woods A. W.
Published: May 2005

We report on an experimental study of the mixing of two miscible fluids in a porous medium driven by either a gravitationally stable or unstable linear displacement flow. A solution of a given NaCl concentration was injected at a constant rate into a homogeneous bead pack saturated with an aqueous solution of different NaCl concentration. The position and width of the fluid interface were recorded using digital image analysis. Our results highlight the strong interplay between gravity and mechanical dispersion. For stable flows, at low Péclet number Pe, the dispersion coefficient increases with Pe, whereas for Pe >500, it becomes constant. Although similar regimes are observed with pure mixing, the stabilizing effect of gravity reduces significantly the dispersion coefficient by a factor of 2–4, even for density contrasts as low as 0.07%. For unstable flows, gravitational instability is delayed by mechanical dispersion. The ratio of the gravitational to background fluid velocity, G, controls the initial diffusive growth of the mixing zone and the time at which the instability subsequently arises. The wavelength of the instability scales with the width of the diffusive mixing zone at onset of instability and its subsequent linear convective growth rate is one fourth of the unstable gravity speed. For natural porous flows, mechanical dispersion can suppress the onset of gravitational instability until the mixing zone is 1–2 m thick. The width of this mixed zone then controls the length scale of the unstable fingers.
How exceptional was the early August 2003 heatwave in France?
Authors: Trigo Ricardo Machado , García‐Herrera Ricardo , Díaz Julio , Trigo Isabel Franco , Valente Maria Antónia
Published: May 2005

The summer of 2003 was characterised by exceptionally warm weather in Europe with the average temperature exceeding that of any previous summer over the last 500 years. The seasonal 2003 summer temperature for central Europe was beyond the historical distribution range and could bear a closer resemblance with climate change scenarios for late XXI century. Nevertheless, it was the heatwave that occurred between the 1st and the 15th of August 2003 that had a major impact in excessive mortality rates throughout Europe, with catastrophic amplitude in France. Here we show, on a daily basis, when and where the magnitude and spatial extent of this heatwave episode has surpassed previous historical maxima, and that this episode is associated with an equally maximum blocking pattern over western Europe. Finally we show that surface and low troposphere air temperature anomalies are particularly well associated with the increased mortality rates in France.
Rapid distortion theory for differential diffusion
Authors: Jackson P. R. , Rehmann C. R. , Sáenz J. A. , Hanazaki H.
Published: May 2005

Rapid distortion theory (RDT) is used to examine differential diffusion of active and passive scalars in unsheared, initially isotropic turbulence. RDT is well suited to study differential diffusion because it applies to strongly stratified flows with weak turbulence—that is, the conditions under which differential diffusion occurs. The theory reproduces several key features of the evolution of scalar fluxes and scalar flux spectra observed in direct numerical simulations (DNS). Predictions of the diffusivity ratio match laboratory results well when a parameter of the theory is related to a parameter of the experiments. RDT also allows parameters such as molecular diffusivities to be varied over a wider range than DNS can currently reach. RDT may prove to be a useful tool for computing mixing in weakly turbulent parts of the stratified ocean interior and possibly for parameterizing subgrid scale mixing in general circulation models.
The vertical structure of ocean heat transport
Authors: Boccaletti G. , Ferrari R. , Adcroft A. , Ferreira D. , Marshall J.
Published: May 2005

One of the most important contributions the ocean makes to Earth's climate is through its poleward heat transport: about 1.5 PW or more than 30% of that accomplished by the ocean‐atmosphere system (Trenberth and Caron, 2001). Recently, concern has arisen over whether global warming could affect this heat transport (Watson et al., 2001), for example, reducing high latitude convection and triggering a collapse of the deep overturning circulation (Rahmstorf, 1995). While the consequences of abrupt changes in oceanic circulation should be of concern, we argue that the attention devoted to deep circulations is disproportionate to their role in heat transport. For this purpose, we introduce a heat function which identifies the contribution to the heat transport by different components of the oceanic circulation. A new view of the ocean emerges in which a shallow surface intensified circulation dominates the poleward heat transport.