bluuebunny/crossref_metadata_2025 huggingface dataset:
A survey of postoperative pain treatment in children of 3–14 years
Authors: Baños Josep‐Eladi , Barajas Conchita , Martin Maria Luisa , Hansen Elisabet , de Cos Maria Angeles , Bosch Félix , Martin Rafael , Marco Joan , Dierssen Trinidad
Published: February 2004

There is a lack of information concerning the characteristics of pediatric postoperative pain in Southern European countries. The aim of this study was to document how postoperative pain in children was managed routinely at Spanish surgical wards.

The study was carried out in three hospitals on the first postoperative day. Children were divided in four groups according to their age (years): Group I (3–5), 11(6–8), III (9–11) and IV (12–14). The parameters evaluated were: analgesia characteristics (type of prescription, drug used and route of administration, prescribed dose and whether the drug was or was not administered, need of non‐prescribed analgesics) and the postoperative pain intensity. The results were analysed using descriptive statistics. U‐Mann Whitney, χ2 ANOVA, Kruskall‐Wallis and Student's t‐test were also used.

A total of 348 children ranging from 3 to 14 years were studied. The average age (± SD) was 8.2 ± 3.3 and the majority were male (74%). Urologic surgery was the most frequent type of operation, with age (p <0.05) and hospital differences (p<0.001). The majority of the patients (52%) were prescribed an analgesic, but only 26% of them had an analgesia order at fixed dosage intervals. Differences among the hospitals were observed (p<0.001). The most commonly used analgesics were metamizol, propyphenazone, paracetamol and codeine. Differences in choice of drug in relation to age and hospital were significant (p < 0.001). Rectal was the preferred route of drug administration. Patient's age was unrelated with the prescribed analgesic dose. An average of 68% of prescriptions were given and half of the patients without scheduled analgesia needed to have analgesics administered. Around 20% of patients had high pain scores.

Few paediatric patients are given analgesics at fixed dose intervals to treat postoperative pain. Pain relief therapy for children differs notably to that of adults, in respect to the drugs prescribed and the administered route.
Capillary blood sampling: relation between lancet diameter, lancing pain and blood volume
Authors: Fruhstorfer Heinrich , Schmelzeisen‐Redeker Gnöther , Weiss Thomas
Published: February 2004

The relation between pain of capillary blood sampling and lancet diameter was studied in 52 healthy subjects. The tips of six fingers were pricked with a Softclix® II lancing device using lancets with identical facet geometry but needle diameters of 0.3, 0.4 and 0.8 mm. Two penetration depths (0.9 and 1.2 mm) were applied. Pain intensity and blood volume were recorded.

At a puncture depth of 0.9 mm, pain did not differ between the three lancets. Pain increased with penetration depth, and at 1.2 mm the thicker lancets were somewhat more painful than the thinner ones. Blood volumes increased with lancet diameter and penetration depth. If the pain for punctures providing just enough blood for a glucose test (≥10 μl) was compared, there was no difference between the lancets.

It can be concluded that lancet diameter is of minor importance for the patient.
Electric stimulation of the cingulum bundle precipitates onset of autotomy induced by inflammation in rat
Authors: Pellicer Francisco , López‐Avila Alberto , Torres‐López Edgar
Published: February 2004

The purpose of this work was to test if electric stimulation of the cingulum bundle in animals subjected to a hindpaw inflammatory process precipitates the onset and enhances autotomy behaviour. Wistar rats were e implanted with bipolar parallel electrodes in the boundary of the cingulum bundle. The inflammatory process was induced in all subjects by injection of carrageenan. The groups were: A, sham; B, implanted and stimulated 10 min daily for 7 days; C, implanted and stimulated 2 h daily, for 7 days. Both groups were injected with CAR 2 days after ending the stimulation period; and D, implanted and stimulated 10 min daily for 5 days, the first stimulation being simultaneous to CAR injection. Results show that 100% of the subjects in stimulated groups presented autotomy as compared with gg% in the sham group. A significant shortening of the onset and increased rates in autotomy were observed in experimental groups (B, C and D) as compared to the sham group. We did not find differences between groups B and C, but there was an increment of autotomy in group D when compared with both B and C groups. We conclude that it is possible to facilitate the onset and to increase the intensity of the autotomy triggered by the inflammatory process with cingulum bundle electrical stimulation. The results also suggest that a fundamental condition to the development of the autotomy in this model is the presence of the noxious inflammatory process.
Molecular epidemiology of cystic echinococcosis
Authors: McMANUS D. P. , THOMPSON R. C. A.
Published: February 2004

Echinococcus granulosusexhibits substantial genetic diversity that has important implications for the design and development of vaccines, diagnostic reagents and drugs effective against this parasite. DNA approaches that have been used for accurate identification of these genetic variants are presented here as is a description of their application in molecular epidemiological surveys of cystic echinococcosis in different geographical settings and host assemblages. The recent publication of the complete sequences of the mitochondrial (mt) genomes of the horse and sheep strains ofE. granulosusand ofE. multilocularis, and the availability of mt DNA sequences for a number of otherE. granulosusgenotypes, has provided additional genetic information that can be used for more in depth strain characterization and taxonomic studies of these parasites. This very rich sequence information has provided a solid molecular basis, along with a range of different biological, epidemiological, biochemical and other molecular-genetic criteria, for revising the taxonomy of the genusEchinococcus. This has been a controversial issue for some time. Furthermore, the accumulating genetic data may allow insight to several other unresolved questions such as confirming the occurrence and precise nature of theE. granulosusG9 genotype and its reservoir in Poland, whether it is present elsewhere, why the camel strain (G6 genotype) appears to affect humans in certain geographical areas but not others, more precise delineation of the host and geographic ranges of the genotypes characterised to date, and whether additional genotypes ofE. granulosusremain to be identified.
Transmission dynamics and control options for Echinococcus granulosus
Authors: TORGERSON P. R. , HEATH D. D.
Published: February 2004

Cystic echinococcosis, caused by the larval stage of Echinococcus granulosus, is a global public health problem. Whilst in a few localities, such as New Zealand, the parasite has been effectively controlled or even eradicated, in most endemic regions it remains a persistent problem. In some areas, such as the former Soviet Union, the disease incidence in humans has increased rapidly in recent years. It is important to have an understanding of the transmission dynamics, both between dogs and domestic livestock where the parasite maintains itself and from dogs to people. It is from this knowledge that effective control measures can be devised to reduce the prevalence of the parasite in animals and hence reduce the incidence of human disease. Mathematical models to describe the transmission of the parasite and the effects of different control strategies were first proposed over twenty years ago. Since then further information has been acquired, new technology has been developed and better computing technology has become available. In this review, we summarise these developments and put together a theoretical framework on the interpretation of surveillance information, how this affects transmission and how this information can be exploited to develop new intervention strategies for the control of the parasite. In particular, the parasite remains a persistent or re-emerging problem in countries of low economic output where resources for an intensive control programme, that has been successful in rich countries, are not available. By understanding of the transmission biology, including mathematical modelling, alternative and cost-effective means of control can be developed.
Transmission ecology ofEchinococcusin wild-life in Australia and Africa
Authors: JENKINS D. J. , MACPHERSON C. N. L.
Published: February 2004

Following the introduction ofE. granulosusinto Australia with domestic animals during European settlement, the parasite quickly became established in theE. granulosus-naive native animals of the continent. The distribution ofE. granulosusin wildlife in Australia is restricted by rainfall, but nevertheless the parasite is currently widespread and highly prevalent in many areas including numerous national parks and privately owned farms. The human population of Africa is rapidly increasing resulting in ever more pressure on wild-life populations and habitat. National parks, reserves and conservation areas now provide important tracts of preserved habitat for maintaining populations of wildlife that are also important in the maintenance ofE. granulosus. In some parts of Africa, hydatid-infected humans provide a source ofE. granulosusinfection to wildlife definitive hosts. In many areas felids may also act as important definitive hosts forE. granulosuswith the parasite being maintained in a prey/predator relationship between lions and a range of intermediate hosts. Populations ofE. granulosus-infected wild-life both in Australia and Africa act as important reservoirs in perpetuating the transmission ofE. granulosusto both domestic animals and humans. In Australia,E. granulosus-infected wild-life is infiltrating urban areas and currently represents a potentially important new public health problem.
Predicting tense: finite verb morphology and subject pronouns in the speech of typically-developing children and children with specific language impairment
Authors: CHAREST MONIQUE J. , LEONARD LAURENCE B.
Published: February 2004

According to the AGREEMENT/TENSE (Agr/Tns) OMISSION MODEL, children's failure to produce finite verb morphemes represents the selection of an optional infinitive form, in which tense and/or agreement is not specified. When agreement is specified, nominative case is licensed. Following the assumptions of this model, a child's utterance such as She run reflects a failure to specify tense only, given that the subject pronoun shows nominative case. We tested this assumption in two studies through the analysis of spontaneous speech samples from young typically-developing (TD) children and children with specific language impairment (SLI). In Study 1, 15 children were included (TD aged 2;1–3;11, SLI aged 4;0–6;2); in Study 2, 33 children were included (TD aged 2;5–3;11, SLI aged 3;6–6;9). We determined whether there was a relationship between the children's use of past tense -ed and their use of third person singular -s and copula is when nominative case was also used. Because nominative case was used, any failures to produce third person singular -s and copula is should be attributable to tense and not agreement. Such use should therefore be related to the children's use of -ed which presumably hinges on tense only. However, a relationship was not found in the speech of either group of children. This was true both for the children in each group who were consistent in using nominative case pronouns and for those who were not. Possible reasons for these findings are discussed.
Learning by ear: on the acquisition of case and gender marking by German-speaking children with normal hearing and with cochlear implants
Authors: SZAGUN GISELA
Published: February 2004

The acquisition of case and gender marking on the definite and indefinite article was studied in a sample of 6 normally-hearing children and 9 children with cochlear implants. Longitudinal spontaneous speech data are used. Children were matched by MLU, with 4 MLU levels: 1·8, 2·8, 3·6, 4·8. Age ranges for normally-hearing children were 1;4 to 3;8 and for children with cochlear implants 1;8 to 7;0. Frequencies of correctly marked article forms increased over MLU but less so in the hearing-impaired group. In both groups error rates were high. However, error patterns were different. In normally-hearing children errors of case predominated, in hearing-impaired children errors of gender and omission. Error patterns suggest that in normally-hearing children syntactic categorization interacts with input frequency and low discriminability of article forms. In the hearing-impaired group the article system is less advanced, despite higher frequencies of definite articles in adult speech. The predominance of article omission is discussed in terms of persisting perceptual problems or a working memory deficit.
Talk about talk with young children: pragmatic socialization in two communities in Norway and the US
Authors: AUKRUST VIBEKE GRØVER
Published: February 2004

Recent studies have suggested that cultures vary in subtle ways in the talk about talk that children hear and learn to produce. Twenty-two three-year-old children and their families in respectively Oslo, Norway and Cambridge, Massachusetts were observed during mealtime with the aim of identifying talk-focused talk. The analysis distinguished talk about (a) language per se, (b) discourse management, and (c) former conversations and use of reported speech. No category of talk-focused talk appeared exclusively in either community, and the frequency of such talk was similar across these. The Oslo families talked more often about language per se and their talk-focused conversations typically had a question–answer form. Talk about talk appeared more often within narratives in Oslo and within explanations in Cambridge. A second analysis compared talk-focused talk at home with such talk at school, suggesting that talk about language per se appeared more often at school across the two communities.
Semantic generality, input frequency and the acquisition of syntax
Authors: THEAKSTON ANNA L. , LIEVEN ELENA V. M. , PINE JULIAN M. , ROWLAND CAROLINE F.
Published: February 2004

In many areas of language acquisition, researchers have suggested that semantic generality plays an important role in determining the order of acquisition of particular lexical forms. However, generality is typically confounded with the effects of input frequency and it is therefore unclear to what extent semantic generality or input frequency determines the early acquisition of particular lexical items. The present study evaluates the relative influence of semantic status and properties of the input on the acquisition of verbs and their argument structures in the early speech of 9 English-speaking children from 2;0 to 3;0. The children's early verb utterances are examined with respect to (1) the order of acquisition of particular verbs in three different constructions, (2) the syntactic diversity of use of individual verbs, (3) the relative proportional use of semantically general verbs as a function of total verb use, and (4) their grammatical accuracy. The data suggest that although measures of semantic generality correlate with various measures of early verb use, once the effects of verb use in the input are removed, semantic generality is not a significant predictor of early verb use. The implications of these results for semantic-based theories of verb argument structure acquisition are discussed.
Postnatal growth and reproductive biology of Rhinolophus hipposideros (Chiroptera: Rhinolophidae)
Authors: Reiter Guido
Published: February 2004

The timing of birth and postnatal growth in lesser horseshoe bats Rhinolophus hipposideros were studied during 2000 and 2001 at three maternity roosts located in the provinces of Carinthia and Salzburg, Austria. Postnatal growth curves for length of forearm and body mass were determined separately for the different colonies and years. Cooler weather during June 2001 coincided with a median birth date that was 8 days later than in 2000, whilst the difference between colonies was 4 and 5 days, respectively, for the pooled data of both years. Cool temperatures in June also coincided with a longer duration of the parturition period. Postnatal growth rates were higher than in most other bat species but differences between years and colonies were considerable. These differences may be attributed to the ambient roost temperatures, whereby the young of two cooler roosts showed significantly reduced growth rate during 8 days of cool weather in 2000. Moreover, later born and therefore smaller pups were more strongly affected by low temperatures than earlier born and larger ones. The mean length of forearm of young lesser horseshoe bats at the beginning of September equalled that of adult bats, whilst their body mass was still lower. Non‐volant juveniles did not cluster following the nightly emergence of adult females, and a preferred location within the roosts could not be identified. High and very low roost temperatures, however, did have an influence on the location of non‐volant young in the colonies.
PCR‐RFLP identification of mustelid species: European mink (Mustela lutreola), American mink (M. vison) and polecat (M. putorius) by analysis of excremental DNA
Authors: Gómez‐Moliner B. J. , Cabria M. T. , Rubines J. , Garin I. , Madeira M. J. , Elejalde A. , Aihartza J. , Fournier P. , Palazón S.
Published: February 2004

Recent advances in molecular scatology have allowed the development of reliable and non‐invasive methods that can be applied in monitoring of small carnivores, without disturbance of the animals. Here a method is described that can be used to differentiate European mink Mustela lutreola, polecat M. putorius and American mink M. vison based on the analysis of DNA extracted from faeces. It consists of a nested PCR of a region of the mitochondrial D‐loop followed by digestion of the resulting 240 bp amplicons with the restriction enzymes RsaI and MspI. The restriction patterns of both enzymes, when used together, are found to detect species‐specific sequence variation. Two different haplotypes for European mink (AA, AB), another two for the polecat (AC, AD) and one for American mink (BC) can also be discriminated by this technique. Two new haplotypes for the mitocondrial D‐loop of mustelids are described after DNA sequencing.
Male mate choice in the Botswana armoured ground cricket Acanthoplus discoidalis (Orthoptera: Tettigoniidae; Hetrodinae). Can, and how, do males judge female mating history?
Authors: Bateman Philip W. , Ferguson J. W. H.
Published: February 2004

In species of many taxa, males alter their investment in ejaculates depending on perceived levels of male–male competition and female mating history/age. Males of the tettigoniid Acanthoplus discoidalis produce a large sperm ampulla and associated spermatophylax, resulting in a long refractory period for males. Female A. discoidalis mate once before laying eggs, and then mate and lay eggs in a random order. The males, therefore, only have a high confidence of paternity when mating with virgins. Male A. discoidalis were studied to determine if they alter their investment in sperm count, spermatophylax mass and water content of spermatophylaces when mating with virgin and non‐virgin females. No difference in investment in any spermatophore characteristics between virgins and non‐virgins was found, but males do reject non‐virgins more often, preferring to transfer spermatophores to virgin females. Males seem to prefer females of a lower mass, where higher mass may reflect increasing female age (and hence likelihood of previous matings) through advanced development of eggs. Outright rejection, rather than changes in spermatophore investment may be because of constraints in tailoring large spermatophores that develop over relatively long periods of time between matings.
Evidence for functional segregation in the directionally asymmetric male genitalia of the spider Metagonia mariguitarensis (González‐Sponga) (Pholcidae: Araneae)
Authors: Huber Bernhard A.
Published: February 2004

The asymmetric male and female genitalia of the spider Metagonia mariguitarensis (González‐Sponga) are described, based on semi‐thin serial sections and SEM photographs, and several male genital and non‐genital characters are measured and analysed statistically. Left male genital bulbs are significantly larger than right bulbs while right palpal tibiae are significantly stronger than left tibiae, suggesting a functional segregation into a more predominantly displaying right palp and a more predominantly sperm‐transferring left palp. Despite several structural differences between right and left male palps, however, there is no indication of qualitative differences: both bulbs transfer sperm, and both palps are provided with a full set of muscles. The female internal genitalia are provided with an unpaired receptacle that is connected to the uterus externus by a wide and complicated duct and to the valve separating uterus externus from uterus internus by a short narrow duct. This resembles entelegyne genitalia, but the functional details remain unknown. The evolution of asymmetric genitalia is discussed in a wider framework, with the conclusion that the causes of asymmetry in spiders may be different from those in other arthropods such as insects and copepods.
Liberalism and the politics of suburbia: electoral dynamics in late nineteenth-century South Manchester
Authors: MOORE JAMES R.
Published: February 2004

The collapse of the Liberal party was arguably the most dramatic feature of British urban politics in the modern period. Many have argued that a major reason for the party's rapid decline was the defection of its suburban support to the Conservatives. By drawing on examples from Manchester, it is argued here that this process was not universal or inescapable. Liberal ideology could still have a strong appeal to the social and educational aspirations of the suburban middle class and their desire for a more genuinely meritocratic society.
Research in urban history: a review of recent theses
Authors: MILLER CAROLINE L.
Published: February 2004

As in previous years this review is based on a broadly based definition of what constitutes ‘urban history’ and consequently includes theses that have been drawn from a variety of disciplines and interpretative structures. Details of the theses have been drawn from the comprehensive material provided through the Index of Theses located at http://www.theses.com/ and Dissertations International located at http://wwwlib.umi.com/dissertations. This review covers a substantial number of theses, sixty in all, and as a result the summaries are rather briefer than in previous years.
Evaluation of text coherence for electronic essay scoring systems
Authors: MILTSAKAKI E. , KUKICH K.
Published: February 2004

Existing software systems for automated essay scoring can provide NLP researchers with opportunities to test certain theoretical hypotheses, including some derived from Centering Theory. In this study we employ the Educational Testing Service's e-rater essay scoring system to examine whether local discourse coherence, as defined by a measure of Centering Theory's Rough-Shift transitions, might be a significant contributor to the evaluation of essays. Rough-Shifts within students' paragraphs often occur when topics are short-lived and unconnected, and are therefore indicative of poor topic development. We show that adding the Rough-Shift based metric to the system improves its performance significantly, better approximating human scores and providing the capability of valuable instructional feedback to the student. These results indicate that Rough-Shifts do indeed capture a source of incoherence, one that has not been closely examined in the Centering literature. They not only justify Rough-Shifts as a valid transition type, but they also support the original formulation of Centering as a measure of discourse continuity even in pronominal-free text. Finally, our study design, which used a combination of automated and manual NLP techniques, highlights specific areas of NLP research and development needed for engineering practical applications.
Mood and modality: out of theory and into the fray
Authors: MCSHANE MARJORIE , NIRENBURG SERGEI , ZACHARSKI RON
Published: February 2004

The topic of mood and modality (MOD) is a difficult aspect of language description because, among other reasons, the inventory of modal meanings is not stable across languages, moods do not map neatly from one language to another, modality may be realised morphologically or by free-standing words, and modality interacts in complex ways with other modules of the grammar, like tense and aspect. Describing MOD is especially difficult if one attempts to develop a unified approach that not only provides cross-linguistic coverage, but is also useful in practical natural language processing systems. This article discusses an approach to MOD that was developed for and implemented in the Boas Knowledge-Elicitation (KE) system. Boas elicits knowledge about any language, L, from an informant who need not be a trained linguist. That knowledge then serves as the static resources for an L-to-English translation system. The KE methodology used throughout Boas is driven by a resident inventory of parameters, value sets, and means of their realisation for a wide range of language phenomena. MOD is one of those parameters, whose values are the inventory of attested and not yet attested moods (e.g. indicative, conditional, imperative), and whose realisations include flective morphology, agglutinating morphology, isolating morphology, words, phrases and constructions. Developing the MOD elicitation procedures for Boas amounted to wedding the extensive theoretical and descriptive research on MOD with practical approaches to guiding an untrained informant through this non-trivial task. We believe that our experience in building the MOD module of Boas offers insights not only into cross-linguistic aspects of MOD that have not previously been detailed in the natural language processing literature, but also into KE methodologies that could be applied more broadly.
Climatological annual cycle of ocean heat content
Authors: Antonov John I. , Levitus Sydney , Boyer Timothy P.
Published: February 2004

Ocean heat content is a major component of earth's energy budget. This paper presents estimates of the climatological annual cycle of upper (0–250 m layer) ocean heat content based on World Ocean Atlas 2001. The land‐ocean ratio is responsible for the geographical distribution of the annual cycle of ocean heat content. Globally, the amplitude of annual harmonic of upper ocean heat content is 3.7 × 1022 J for the World Ocean, 10.2 × 1022J for the Southern Hemisphere, and 6.5 × 1022J for the Northern Hemisphere.
Ground‐based measurements of halogen oxides at the Hudson Bay by active longpath DOAS and passive MAX‐DOAS
Authors: Hönninger G. , Leser H. , Sebastián O. , Platt U.
Published: February 2004

Intensive field measurements were carried out on the southeast coast of the Hudson Bay (55°N, 75°W) in spring 2001. The study focussed on reactive halogen chemistry and ozone/mercury depletion in the Hudson Bay region/Canadian lower Arctic. Several events of enhanced bromine oxide (BrO) coinciding with ozone depletion in the boundary layer (BL) were simultaneously measured by active longpath differential optical absorption spectroscopy (LP‐DOAS) and passive multi axis differential optical absorption spectroscopy (MAX‐DOAS). Significant differences in intensity and duration of ozone depletion events compared to high latitudes can be explained considering the daily alternation of daylight/nighttime which prevents complete ozone depletion within one day. First simultaneous measurements of active LP‐DOAS and passive MAX‐DOAS were carried out and compared. While LP‐DOAS monitored precise concentration values near the surface, MAX‐DOAS also captured BrO layers elevated from the surface which could not be seen by LP‐DOAS.
Temperature dependence of elastic moduli of β‐(Mg, Fe)2SiO4
Authors: Mayama Norihito , Suzuki Isao , Saito Toshiaki , Ohno Ichiro , Katsura Tomoo , Yoneda Akira
Published: February 2004

The elastic moduli of polycrystalline wadsleyite, β‐(Mg0.91Fe0.09)2SiO4, were measured up to 470 K by means of the resonant sphere technique. The adiabatic bulk (KS) and shear (μ) moduli were found to be 165.72(6) and 105.43(2) GPa at room temperature. The average slopes (dKS/dT and dμ/dT) in the range were determined to be −0.0175(3) and −0.0159(1) GPa/K. We estimated that the P‐, S‐wave velocity and density jumps for the α‐ to β‐phase transformation at the 410‐km depth condition were 9.5, 11.2 and 5.4%, respectively. These results suggest that the olivine component at the depth should be 52 and 42 volume % for P‐ and S‐waves.
Unusual ionospheric echoes with high velocity and very low spectral width observed by the SuperDARN radars in the polar cap during high geomagnetic activity
Authors: Nishitani Nozomu , Lester Mark , Milan Steve E. , Ogawa Tadahiko , Sato Natsuo , Yamagishi Hisao , Yukimatu Akira Sessai , Rich Frederick J.
Published: February 2004

The spectral width of the ionospheric backscatter echoes obtained with the SuperDARN radars has been regarded as a useful tool for locating specific ionospheric regions such as the cusp. In this paper we report the presence of ionospheric echoes with high (>450 m/s) Doppler velocity and very low (<60 m/s) spectral width, observed by the CUTLASS and Syowa East and South SuperDARN radars. These echoes have the following characteristics. (1) They have a close correlation with geomagnetic activity such that as the Dst index decreases, the radars tend to observe ionospheric echoes with high Doppler velocity and very low spectral width more frequently. (2) Their existence does not depend on magnetic local time. (3) They are located preferably in the polar cap region, where antisunward convection prevails. (4) They sometimes exist over a wide range, so they are more likely to be F‐region rather than E‐region echoes. The occurrence of these echoes during active periods is associated with the suppression of the electric field turbulence. The present result appears consistent with the previous paper by Golovchanskaya et al. [2002], who showed the negative correlation between the electric field turbulence level and geomagnetic activity.
Thin electron current sheets and their relation to auroral potentials
Authors: Birn Joachim , Schindler Karl , Hesse Michael
Published: February 2004

Using the two‐dimensional, steady‐state Vlasov theory derived in a previous paper, we further investigate properties of thin current sheets that result from exact particle motion. The self‐consistent quasi‐neutral structure of thin current sheets generally requires the presence of an electric potential, which is constant along field lines. We establish that potential differences of up to the ion thermal potential kTi/e may be present when the current sheet thickness becomes comparable to or smaller than a typical ion Larmor radius. We further explore the possible association of thin current sheets with the perpendicular electric fields that are part of the U‐shaped potential structures above auroral arcs. For sufficiently small scales, the converging perpendicular electric field corresponds to two oppositely directed thin Hall current sheets. We construct such double current sheet models and confirm that they result in potentials with the postulated shape and, for sufficiently small scales, in substantial potential differences (in fractions of the ion thermal potential kTi/e). The formation of such double current sheets, found recently in simulations of an earthward collapsing entropy‐depleted magnetic flux tube (“bubble”), may provide a further link between bursty bulk flows, bubbles, and auroral features.
Oceanic effects on polar motion determined from an ocean model and satellite altimetry: 1993–2001
Authors: Chen J.‐L. , Wilson C. R. , Hu X.‐G. , Zhou Y.‐H. , Tapley B. D.
Published: February 2004

Mass redistribution and motion in the oceans are major driving forces of geodetic variations, including polar motion, length of day, geocenter, and gravity field changes. We examine oceanic contribution to polar motion using estimates from a data‐assimilating ocean general circulation model and satellite radar altimeter observations. The data include model estimates of variations in oceanic mass (OBP) and meridional and zonal velocities. Sea level anomalies from TOPEX/Poseidon (T/P) satellite altimeter measurements and steric sea surface height changes deduced from the model are also used to estimate OBP effects. Estimated oceanic contributions from both the model and T/P show considerably better agreement with polar motion observations compared with results from previous studies. The improvement is particularly significant at intraseasonal timescales. Both OBP and ocean current variations provide important contributions to polar motion. At intraseasonal timescales the oceans appear to be a dominant contributor to residual polar motion not accounted for by the atmosphere. The oceans also play an important role in seasonal excitation. Combined OBP and ocean current contributions explain much of the residual semiannual variability.
Transient rip currents and nearshore circulation on a swell‐dominated beach
Authors: Johnson D. , Pattiaratchi C.
Published: February 2004

Eulerian and Lagrangian measurements of nearshore circulation on a longshore uniform beach with perpendicularly incident swell waves are described. Both the Eulerian and Lagrangian data show a variable rotational part of the current field that is distinct from, but coexists with, that due to infragravity waves. A well‐defined feature of the flow field includes transient rip currents, which occur in varying locations and are not topographically controlled. Drifter trajectories show that the rips behave like a shallow plane jet, consisting of a constrained neck region that flows into a spreading head region. There is continuous modulation of the flow within the rip neck. Estimates of the length scale across the rip neck using two‐particle statistics are 20–30 m. Well‐defined discrete vortex features are observed at the initiation point of one of the necks and in one of the rip heads. Estimated dispersion values suggest that mixing is greatly enhanced outside the surf zone by the intermittent presence of the rip heads. The dispersion calculated from both inside and outside the surf zone appears to show scale dependence with a power law close to 4/3 in a similar way to oceanic turbulence at much larger scales.
Nongenomic stimulation of vacuolar H
+
-ATPases in intercalated renal tubule cells by aldosterone
Authors: Winter Christian , Schulz Nicole , Giebisch Gerhard , Geibel John P. , Wagner Carsten A.
Published: February 2004

Renal collecting ducts play a critical role in acid–base homeostasis by establishing steep transepithelial pH gradients necessary for the almost complete reabsorption of bicarbonate and the effective secretion of ammonium into the urine. The mechanisms of urine acidification in collecting ducts involve active, electrogenic hydrogen (H
+
) secretion and, less importantly, potassium (K
+
)-H
+
exchange. Deranged renal acidification and the inability to lower urine pH are hallmarks of distal tubular acidosis and often result from inborn errors of metabolism involving vacuolar H
+
-ATPase subunits in the collecting ducts. Three factors regulate H
+
-ATPase activity in intercalated cells of collecting ducts: the acid–base status, angiotensin II, and aldosterone. Most effects of aldosterone involve activation of the mineralocorticoid receptor and genomic changes in transcription and protein synthesis. Here we demonstrate a nongenomic pathway of vacuolar H
+
-ATPase activation in intercalated cells of isolated mouse outer medullary collecting ducts (OMCD).
In vitro
exposure of isolated outer medullary collecting ducts to aldosterone (10 nM) for times as short as 15 min increases vacuolar H
+
-ATPase activity ≈2- to 3-fold. Neither inhibition of mineralocorticoid receptors nor of transcription and protein synthesis prevented aldosterone-induced stimulation of H
+
-ATPase. Incubation with colchicine, however, abolished the stimulatory effect of aldosterone, suggesting a role of the microtubular network for H
+
-ATPase stimulation. Immunohistochemistry in kidneys from aldosterone-injected mice showed increased apical H
+
-ATPase staining in OMCD-intercalated cells. The stimulatory effect of aldosterone was associated with a transient rise in intracellular Ca
2+
and required intact PKC. Thus, rapid nongenomic modulation of vacuolar H
+
-ATPase activity in OMCD-intercalated cells by aldosterone may play an additional role in hormonal control of systemic acid–base homeostasis.
Negative regulation of IFN-α/β signaling by IFN regulatory factor 2 for homeostatic development of dendritic cells
Authors: Honda Kenya , Mizutani Tatsuaki , Taniguchi Tadatsugu
Published: February 2004

The development and cooperation of distinct subsets of antigen-presenting cells, particularly dendritic cells (DCs), may be critical for maintaining homeostatic immune responses. Recently, much attention has been focused on IFN-α/β, the cytokines induced
en masse
by virus infection or the activation of Toll-like receptors, in the context of DC activation. Here, we show that mice deficient in IFN regulatory factor 2 exhibit selective loss of CD8α
–
DCs, the so-called myeloid DCs, which is accompanied by a notable increase in CD11c
–
CD11b
high
other myeloid lineage cells. Such deficiency is intrinsic to the bone marrow precursors, in which the abnormal induction of
IFN
-α/β genes causes excessive IFN signaling. The critical function of IFN regulatory factor 2 in the negative regulation of IFN-α/β signaling is underscored by the observation that the deficiency is rescued by introducing an additional null mutation for the IFN receptor complex. In view of accumulating evidence of the critical role of IFN-α/β signaling in DC activation, our present study offers a unique example in that the magnitude of a cytokine signal should be properly balanced in a stage-specific manner during the differentiation and activation of DCs.
The Bik BH3-only protein is induced in estrogen-starved and antiestrogen-exposed breast cancer cells and provokes apoptosis
Authors: Hur Jingyung , Chesnes Jessica , Coser Kathryn R. , Lee Roseanna S. , Geck Peter , Isselbacher Kurt J. , Shioda Toshi
Published: February 2004

Evidence has been accumulating that some estrogen-dependent human breast cancers require estrogen for not only proliferation but also survival. To obtain insights into the molecular mechanisms of apoptosis of breast cancer cells subjected to estrogen starvation or exposed to antiestrogens, we characterized changes in the gene expression profile of MCF-7/BUS human breast cancer cells and revealed a strong induction of Bik, a member of the BH3-only proapoptotic proteins. The Bik mRNA transcript and protein were strongly induced by estrogen starvation or exposure to fulvestrant, a pure antiestrogen that competes with the natural estrogens for binding to the estrogen receptors. This Bik induction preceded apoptotic cell death, which was blocked by zVAD-fmk, a pancaspase inhibitor. Amounts of the Bcl-2-related proteins, such as Bcl-2, Bcl-X
L
, or Bax, showed only marginal changes in the presence or absence of estrogens or antiestrogens. Suppression of Bik expression by using the small interfering RNA effectively blocked the fulvestrant-induced breast cancer cell apoptosis. These results indicate that Bik is induced in MCF-7/BUS cells in the absence of estrogen signaling and plays a critical role in the antiestrogen-provoked breast cancer cell apoptosis.
The human olfactory receptor gene family
Authors: Malnic Bettina , Godfrey Paul A. , Buck Linda B.
Published: February 2004

Humans perceive an immense variety of chemicals as having distinct odors. Odor perception initiates in the nose, where odorants are detected by a large family of olfactory receptors (ORs). ORs have diverse protein sequences but can be assigned to subfamilies on the basis of sequence relationships. Members of the same subfamily have related sequences and are likely to recognize structurally related odorants. To gain insight into the mechanisms underlying odor perception, we analyzed the human OR gene family. By searching the human genome database, we identified 339 intact OR genes and 297 OR pseudogenes. Determination of their genomic locations showed that OR genes are unevenly distributed among 51 different loci on 21 human chromosomes. Sequence comparisons showed that the human OR family is composed of 172 subfamilies. Types of odorant structures that may be recognized by some subfamilies were predicted by identifying subfamilies that contain ORs with known odor ligands or human homologs of such ORs. Analysis of the chromosomal locations of members of each OR subfamily revealed that most subfamilies are encoded by a single chromosomal locus. Moreover, many loci encode only one or a few subfamilies, suggesting that different parts of the genome may, to some extent, be involved in the detection of different types of odorant structural motifs.
Differential recruitment of nuclear receptor coactivators may determine alternative RNA splice site choice in target genes
Authors: Auboeuf Didier , Dowhan Dennis H. , Kang Yun Kyoung , Larkin Kimberly , Lee Jae Woon , Berget Susan M. , O'Malley Bert W.
Published: February 2004

The biological consequences of steroid hormone-mediated transcriptional activation of target genes might be difficult to predict because alternative splicing of a single neosynthesized precursor RNA can result in production of different protein isoforms with opposite biological activities. Therefore, an important question to address is the manner in which steroid hormones affect the splicing of their target gene transcripts. In this report, we demonstrate that individual steroid hormones had different and opposite effects on alternative splicing decisions, stimulating the production of different spliced variants produced from genes driven by steroid hormone-dependent promoters. Steroid hormone transcriptional effects are mediated by steroid hormone receptor coregulators that also modify alternative splicing decisions. Our data suggest that activated steroid hormone receptors recruit coregulators to the target promoter that participate in both the production and the splicing of the target gene transcripts. Because different coregulators activating transcription can have opposite effects on alternative splicing decisions, we conclude that the precise nature of the transcriptional coregulators recruited by activated steroid receptors, depending on the promoter and cellular contexts, may play a major role in regulating the nature of the spliced variants produced from certain target genes in response to steroid hormones.
Cells adapted to high NaCl have many DNA breaks and impaired DNA repair both in cell culture and
in vivo
Authors: Dmitrieva Natalia I. , Cai Qi , Burg Maurice B.
Published: February 2004

Acute exposure of cells in culture to high NaCl damages DNA and impairs its repair. However, after several hours of cell cycle arrest, cells multiply in the hypertonic medium. Here, we show that, although adapted cells proliferate rapidly and do not become apoptotic, they nevertheless contain numerous DNA breaks, which do not elicit a DNA damage response. Thus, in adapted cells, Mre11 exonuclease is mainly present in the cytoplasm, rather than nucleus, and histone H2AX and chk1 are not phosphorylated, as they normally would be in response to DNA damage. Also, the adapted cells are deficient in repair of luciferase reporter plasmids damaged by UV irradiation. On the other hand, the DNA damage response activates rapidly when the level of NaCl is reduced. Then, Mre11 moves into the nucleus, and H2AX and chk1 become phosphorylated. Renal inner medullary cells
in vivo
are normally exposed to a variable, but always high, level of NaCl. As with adapted cells in culture, inner medullary cells in normal mice exhibit numerous DNA breaks. These DNA breaks are rapidly repaired when the NaCl level is decreased by injection of the diuretic furosemide. Moreover, repair of DNA breaks induced by ionizing radiation is inhibited in the inner medulla. Histone H2AX does not become phosphorylated, and repair synthesis is not detectable in response to total body irradiation unless NaCl is lowered by furosemide. Thus, both in cell culture and
in vivo
, although cells adapt to high NaCl, their DNA is damaged and its repair is inhibited.
Heterodimeric interactions among the 1-amino-cyclopropane-1-carboxylate synthase polypeptides encoded by the
Arabidopsis
gene family
Authors: Tsuchisaka Atsunari , Theologis Athanasios
Published: February 2004

The pyridoxal phosphate-dependent enzyme, 1-aminocyclopropane-1-carboxylate synthase (ACS; EC 4.4.1.14), catalyzes the rate-limiting step in the ethylene biosynthetic pathway in plants. The
Arabidopsis
genome encodes nine ACS polypeptides that form eight functional (ACS2, ACS4 –9, ACS11) and one nonfunctional (ACS1) homodimers. Because the enzyme is a homodimer with shared active sites, the question arises whether the various polypeptides can form functional heterodimers. Intermolecular complementation experiments in
Escherichia coli
by coexpressing the K278A and Y92A mutants of different polypeptides show that all of them have the capacity to heterodimerize. However, functional heterodimers are formed only among gene family members that belong to one or the other of the two phylogenetic branches. ACS7 is an exception to this rule, which forms functional heterodimers with some members of both branches when it provides the wt K278 residue. ACS1, the nonfunctional polypeptide as a homodimer, can also form functional heterodimers with members of its phylogenetic branch when its partners provide the wt K278 residue. The ACS gene family products can potentially form 45 homo- and heterodimers of which 25 are functional. Bimolecular fluorescence complementation and biochemical coaffinity purification assays show that the inactivity of certain heterodimers is not due to the absence of heterodimerization but rather to structural restraint(s) that prevents the shared active sites from being functional. We propose that functional heterodimerization enhances the isozyme diversity of the
ACS
gene family and provides physiological versatility by being able to operate in a broad gradient of
S
-adenosylmethionine concentration in various cells/tissues during plant growth and development. Nonfunctional heterodimerization may also play a regulatory role during the plant life cycle.
Agonist-induced Ca
2+
entry determined by inositol 1,4,5-trisphosphate recognition
Authors: van Rossum Damian B. , Patterson Randen L. , Kiselyov Kirill , Boehning Darren , Barrow Roxanne K. , Gill Donald L. , Snyder Solomon H.
Published: February 2004

It has been considered that Ca
2+
release is the causal trigger for Ca
2+
entry after receptor activation. In DT40 B cells devoid of inositol 1,4,5-trisphosphate receptors (IP
3
R), the lack of Ca
2+
entry in response to receptor activation is attributed to the absence of Ca
2+
release. We reveal in this article that IP
3
R recognition of IP
3
determines agonist-induced Ca
2+
entry (ACE), independent of its Ca
2+
release activity. In DT40 IP
3
R
–/–
cells, endogenous ACE can be rescued with type 1 IP
3
R mutants (both a ΔC-terminal truncation mutant and a D2550A pore mutant), which are defective in Ca
2+
release channel activity. Thus, in response to B cell receptor activation, ACE is restored in an IP
3
R-dependent manner without Ca
2+
store release. Conversely, ACE cannot be rescued with mutant IP
3
Rs lacking IP
3
binding (both the Δ90–110 and R265Q IP
3
-binding site mutants). We conclude that an IP
3
-dependent conformational change in the IP
3
R, not endoplasmic reticulum Ca
2+
pool release, triggers ACE.