bluuebunny/crossref_metadata_2025 huggingface dataset:
Treatment of acute salpingitis with sulbactam/ampicillin
Authors: Bruhat M.A. , LeBouedec G. , Pouly J.L. , Mage G. , Canis M.
Published: May 2004

The combination of sulbactam/ampicillin was compared to cefoxitin for the treatment of acute salpingitis in 40 women divided into two groups of 20 women each. There were 11 patients in each group who were given doxycycline because of evidence of chlamydial infection. All patients were diagnosed by laparoscopic examination and evaluated by the same procedure 7–12 weeks later. At the second laparoscopy, only 1 of the 20 patients (5%) treated with sulbactam/ampicillin had severe adhesions, while 6 of the 20 patients (40%) treated with cefoxitin had severe adhesions. Tubal patency was without obstruction in 14 patients (70%) given the combination treatment and in 12 patients (60%) given cefoxitin. Side effects were essentially absent in both groups.
Labor outcome of juvenile primiparae in a population with a high incidence of contracted pelvis
Authors: Fisk N.M. , Shweni P.M.
Published: May 2004

Labor outcome of primiparae less than 17 years was compared with non‐juvenile primiparae in a population with a high incidence of contracted pelvis. Juvenile primiparae were referred to hospital on the basis of age, whereas non‐juveniles were referred for an obstetric complication. There was no statistical difference in rates of cesarean section, Ventouse, operative delivery, low birth weight, or perinatal mortality between 538 juveniles and 5294 older “high risk” mothers. Symphysiotomy rates were actually higher in the juveniles (12.6% vs. 9.7%, P < 0.05). These data support the practice of hospital referral for juvenile African women in labor.
Urinary excretion of N‐acetyl‐β‐d‐glucosaminidase and alanine aminopeptidase during pregnancy
Authors: Strigini F. , Melis G.B. , Gasperini M. , Ronca G. , Palmieri L. , Fioretti P.
Published: May 2004

The assay of enzyme activity in urine seems a reliable and safe method to monitor different kidney diseases. However, its use in pregnant patients might be limited by the modifications of kidney function during pregnancy. The aim of the present study was to evaluate the trend of excretion of the lysosomal enzyme N‐acetyl‐β‐d‐glucosaminidase (NAG) and the brush border enzyme alanine aminopeptidase (AAP) during uncomplicated pregnancies. NAG excretion showed a significant increase (P < 0.001) throughout pregnancy, while no significant modification of AAP levels was demonstrated. These data support the hypothesis that the two enzymes are excreted into the urine through different mechanisms and might constitute markers for different pathological events. As the increase of NAG excretion may be related to the kidney functional adaptation to pregnancy, different cut‐off limits must be established in this period.
Postcoital vesico‐vaginal fistula following surgery for cancer cervix
Authors: Oumachigui A. , Reddy N.S. , Rajaram P.
Published: May 2004

A 25‐year‐old parous woman was treated with radical hysterectomy for cancer of the cervix. Six months later she developed a vesico‐vaginal fistula following coitus. The fistula was repaired and vaginal reconstruction performed. Sexual dysfunction and the need for vaginal reconstruction are discussed.
Placental malaria and pregnancy outcome
Authors: Ibhanesebhor S.E. , Okolo A.A.
Published: May 2004

Malaria parasitemia was assessed in 312 placentae of singleton deliveries in Benin. The prevalence rate was 45.19%. The dominant infecting specie was Plasmodium falciparum. High density parasitemia of placental smear in 44.68% was associated with preterm delivery, low birthweight, intrauterine growth retardation and neonatal mortality. Placental histological diagnosis of malaria in 57.69% was more frequently associated with intrauterine growth retardation. Extraplacental parasitemia decreased but intraplacental parasitemia increased with gestational age.
Prolonged pregnancy: the management dilemma
Authors: Herabutya Y. , ‐Prasertsawat P.O. , Tongyai T. , Isarangura Na Ayudthya N.
Published: May 2004

In a prospective randomized study, pregnancies with unfavorable cervix and well established gestational age of at least 42 weeks were selected for management by either antepartum fetal testing or prostaglandin gel induction of labor. Of the 108 pregnancies studied, 57 (53%) had labor induced and 51 (47%) continued without intervention. Comparison of the two groups showed no difference in meconium staining, fetal distress, length of first stage of labor, the need for intervention, or the mode of delivery. In terms of Apgar score the neonatal outcome was not significantly different but a greater proportion of the babies (7.8% versus 1.8%) in the noninduced group required intubation. Our data show that there is no particular advantage in letting the pregnancy go beyond 42 completed weeks of gestation especially if prostaglandin is available for induction of labor.
The challenge of grandmultiparity in Nigerian obstetric practice
Authors: Ozumba B.C. , Igwegbe A.O.
Published: May 2004

A retrospective analysis of 733 Nigerian grandmultiparae seen at the University of Nigeria Teaching Hospital (UNTH) over a 3 year period was carried out. A high incidence of grandmultiparity (11%) was noted, and most of them (62%) belonged to the lower socioeconomic class. Anemia, hypertensive diseases, abruptio placentae, breech presentation and abnormal lie were significant complications of grandmultiparity. The incidence of multiple pregnancy, low birthweight babies, cesarean deliveries and perinatal deaths were markedly increased in the grandmultipara. Improvement in socioeconomic conditions of the populace, health education and widespread practice of family planning are suggested to reduce the incidence of grandmultiparity.
A conservative surgical treatment of cervical pregnancy with active bleeding ‐ uterine artery ligation and cervicotomy
Authors: Su T.H. , Wang Y.D. , Chen C.P. , Lei S.Y.
Published: May 2004

Cervical pregnancy complicated with massive bleeding usually results in abdominal hysterectomy, and thus the patient loses her fertility potential. Conservative management to control active hemorrhaging as well as to preserve reproductive function is necessary for women who desire more children. We present four patients with cervical pregnancy, complicated by life threatening hemorrhage, who were successfully treated with uterine artery ligation and cervicotomy. Subsequently, one patient had two successful term pregnancies delivered by cesarean section.
Bilateral and synchronous cervical carcinoma in situ in a didelphic uterus
Authors: Bakri Y. , Salem H. , Sadi A.R. , Mansour M.
Published: May 2004

A case is reported of a bilateral and synchronous cervical squamous cell carcinoma in situ in a patient with uterus didelphys. Bilateral simultaneous conizations of both cervices were curative. Theories of tumor origin in such a case are discussed.
A new nonsurgical technique for termination of intrauterine pregnancy associated with large multiple uterine leiomyomas
Authors: Buckshee K. , Dhond A.J.
Published: May 2004

Medical termination of a first trimester intrauterine pregnancy associated with large and multiple leiomyomas posed a unique problem because the sac was inaccessible per vaginum for surgical or vacuum evacuation. The use of prostaglandins was contraindicated due to a past history of bronchial asthma. But intraamniotic and intraplacental instillation of methotrexate, 25 mg at each site, under ultrasound guidance resulted in termination of pregnancy. No side effects or complications were observed after the procedure.
The obstetric performance of sickle cell disease patients and homozygous hemoglobin C disease patients in Ile‐Ife, Nigeria
Authors: Dare F.O. , Makinde O.O. , Faasuba O.B.
Published: May 2004

In a 9‐year period (1980–1988), 46 delivered hemoglobinopathy patients were studied. There was a high incidence of complications during pregnancy. The perinatal and maternal mortalities were 13.4% and 9.2% respectively. The complications could be minimized by adequate supervision in pregnancy, labor and puerperium.
Sonographic assessment of the incompetent cervix in pregnancy
Authors: Nzeh D.A. , Adetoro O.O.
Published: May 2004

Ultrasonography (US) was done in 40 women with a history of recurrent midtrimester abortion. The results were compared with those of a control group who consisted of 53 women with no previous history of abortion and had had at least one full term pregnancy with normal vaginal delivery. Mean internal cervical os diameters of 16.0 mm and 22.5 mm at 10 and 27 weeks gestation respectively were recorded in the cervical incompetent patients while mean values of 7.7 mm and 14.5 mm at 13 and 28 weeks gestation were observed in the normal control subjects. Full analysis of covariance showed statistically significant difference in the internal os diameter between the control group and the cervical incompetence cases (t90 = 9.33, P < 0.001).
Vaginal microbial flora as a cofactor in the pathogenesis of uterine cervical intraepithelial neoplasia
Authors: Guijon F. , Paraskevas M. , Rand F. , Heywood E. , Brunham R. , McNicol P.
Published: May 2004

The vaginal microbial flora of 106 women with histopathologically confirmed cervical intraepithelial neoplasia and 79 women without disease, was evaluated for Gardnerella vaginalis, Trichomonas vaginalis, Candida albicans and other yeasts. Flora morphology was assessed by gram staining of secretions. Cervical cultures were examined for Herpes Simplex virus, Cytomegalovirus and Neisseria gonorrhoeae. Chlamydia trachomatis antigens in cervical secretions were detected by enzyme immunoassay. Human Papillomavirus was identified by koilocytosis in cytologic or histopathologic specimens. Human Papillomavirus infection (P < 0.00001), vaginal infection with Mycoplasma hominis (P = 0.012) and abnormal vaginal flora (P = 0.006) were significantly associated with CIN, suggesting that CIN may be promoted by vaginal microorganisms in conjunction with human papillomavirus cervical infection.
Cytomegalovirus hepatitis in late pregnancy
Authors: Makkonen M. , Huttunen M. , Martikainen A. , Saarikoski S.
Published: May 2004

A case of pregnancy complicated by cytomegalovirus hepatitis is represented. The mother had a fulminant disease, but she delivered spontaneously at 31 weeks of gestation. The baby was unnaffected.
Carcinoma of the uterine cervix and schistosomiasis
Authors: Moubayed P. , Lepère J.‐F. , Mwakyoma H. , Neuvians D.
Published: May 2004

OBJECTIVES: To determine the incidence of carcinoma of the uterine cervix and its relationship to schistosomiasis infection. METHODS: A retrospective analysis of a 10‐year period (1980–1990) at the department of histopathology (cancer registry) of the University of Dar es Salaam using statistical evaluation of the proportional rate of histomorphological diagnosis, clinical symptoms and epidemiological aspects. RESULTS: There were 4520 cases classified as cervical carcinoma. Unexpectedly, only 76 of these (1.7%) revealed an association with schistosomiasis. Precancerous lesions of the squamous epithelium of the uterine cervix were a relatively common feature in carcinoma of both groups. Furthermore, epidemiological analysis indicates that the occurrence of cancer and schistosomiasis infection of the cervix is not strictly confined to the population of rural regions, known as endemic areas, with low hygienic and socioeconomic standards. This fact is most probably due to the rural people moving into urban areas, hoping to improve their quality of life. CONCLUSIONS: Our data do not support the assumption of an etiologic role of schistosomiasis in the oncogenesis of cervical carcinoma.
Acardiac anomaly
Authors: Loh S.F. , Tee C.S. , Chew S.Y.
Published: May 2004

Two cases of acardius, one in a twin and the other in a triplet pregnancy are presented. The obstetrical significance and current management options are discussed.
Second trimester sonographically diagnosed placenta previa: Prediction of persistent previa at birth
Authors: Zelop C.C. , Bromley B. , Frigoletto F.D. , Benacerraf B.R.
Published: May 2004

OBJECTIVES: We sought to determine the natural history of second trimester sonographically diagnosed placenta previa, and to ascertain whether the position of the placenta with respect to the cervical os at second trimester sonography can accurately predict persistence of the placenta previa at term. METHODS: The study population included all women consecutively diagnosed by ultrasound with placenta previa between 14 and 20 weeks' gestation. Medical records of the patients requiring cesarean section were reviewed to determine the presence of placenta previa. We reviewed the second trimester sonogram of patients who underwent abdominal delivery for placental and nonplacental indications to determine whether the central (symmetrical) versus the partial (asymmetrial) position of the placenta with respect to the internal os predicted the presence of placenta previa at delivery. RESULTS: A total of 925 second trimester‐patients were sonographically identified as having placenta previa. Two hundred and sixty seven patients underwent cesarean delivery, 43 of which had placenta previa (43/925 or 4.6%). Twenty‐two of the 43 were asymptomatic without anteparturn bleeding. Analysis of the second trimester position of the placenta revealed that symmetry of the placenta with respect to the internal os at second trimester scan had a sensitivity of 49% for prediction of placenta previa at birth. CONCLUSIONS: The degree of placental symmetry with respect to the internal os during the second trimester successfully predicted the previas most likely to persist at delivery with a sensitivity of 49% (95% CI 34–64) and specificity of 93%.
Grandmultiparity — not to be feared? An analysis of grandmultiparous women receiving modern antenatal care
Authors: Hughes P.F. , Morrison J.
Published: May 2004

OBJECTIVE: To document the reproductive performance of grandmultiparous women receiving modern antenatal care. METHODS: A cross‐sectional study of 2784 multiparous (882 grandmultiparous) mothers delivered in a base hospital obstetric unit staffed by westerntrained midwives and consultant obstetrical staff. RESULTS: There were minimal differences in major antenatal, peripartum and neonatal outcome events, with the exception of a high rate of gestational and pre‐existing diabetes. CONCLUSIONS: This data supports the opinion that grandmultiparity per se is not necessarily a major risk factor for either mother or fetus. Similarly, the mature grandmultigravida in this population was not at significantly increased risk of the alleged associations of increased parity and advancing maternal age, with the exception of diabetes. Together with the combined prevalence of maternal anemia this requires further investigation and probable intervention, particularly in the light of recent speculation concerning the fetal and infant origins of adult disease.
Detection of congenital cytomegalovirus infection by using chorionic villi of the early pregnancy and polymerase chain reaction
Authors: Dong Z.‐W. , Yan C. , Yi W. , Cui Y.‐Q.
Published: May 2004

OBJECTIVE: To detect congenital cytomegalovirus (CMV) infection of chorionic villi in early pregnancy. METHODS: Extraction of DNA of chorionic villi and amplification of the gene of major immediate‐early (MIE) antigen of CM V using a polymerase chain reaction (PCR). RESULTS: Sixty‐eight specimens of chorionic villi and 16 specimens were positive for CMV infection by PCR. The incidence of congenital CMV infection in the first trimester of pregnancy was 23.5%. CONCLUSIONS: The risk of transmission of CMV from mother to fetus in early pregnancy is very high and potential CMV carriers may transmit CMV to their fetus in early pregnancy.
Reconstruction of the external genitalia in females with bladder exstrophy
Authors: Damario M.A. , Carpenter S.E. , Jones H.W. , Rock J.A.
Published: May 2004

OBJECTIVES: A very characteristic genital anomaly accompanies bladder exstrophy in females. This includes anterior displacement and narrowing of the vagina and separation of the clitoris into two distinct bodies. The authors have had a relatively large experience with correction of this rare genital anomaly. From this experience, it began to appear that certain procedural details were associated with improved outcomes. The objective of this article was to review this experience and detail the reconstruction of the external genitalia in these patients. METHODS: All cases of bladder exstrophy in females presenting from January 1, 1970 to December 31, 1992 were reviewed. A total of eight patients who underwent surgical correction of the external genitalia were included. Data was obtained regarding urologic treatment, associated anomalies, corrective gynecologic procedures, complications and subsequent course. RESULTS: Corrective gynecologic surgery included enlargement of the vaginal orifice in all eight patients. Five patients had reapproximation of the bifid clitoris. Three patients performed postoperative dilatation therapy. Postoperatively, one patient experienced dyspareunia requiring a repeat procedure to enlarge the vaginal orifice. No patient had complications related to pelvic organ prolapse. CONCLUSIONS: Care should be taken not to extend the perineal incision too far posteriorly in reconstruction of the external genitalia in females with bladder exstrophy. Failure to do so may further predispose the patient to uterine prolapse. Postoperative dilator therapy may be an important adjunctive technique.
Prothymosin α is localized in mitotic spindle during mitosis⋆
Authors: Vareli Katerina , Frangou‐Lazaridis Maria
Published: May 2004

Summry— Prothymosin a is a small, acidic, ubiquitous protein, thought to play a role in cell proliferation, carcinogenesis and apoptosis. We have reported earlier that in the interphase nucleus prothymosin a exhibits a punctuated nuclear distribution associated with transcription sites. Moreover, the protein was found to localize in 1‐6 subnuclear domains where PML and CstF64 proteins were also identified. In the present study we followed the subcellular distribution of prothymosin a during mitosis. Our data identify prothymosin a to colocalize with α‐tubulin in the mitotic spindle throughout mitosis, and to decorate the midbody during cytokinesis. Moreover nocodazole treatment disrupted prothymosin α and α‐tubulin colocalization at the centrosomes of the interphase cell. Prothymosin a was also found to decorate γ‐tubulin identified centrosomes, during mitosis. Taken together our colocalization study suggests involvement of prothymosin a, in the formation, maintenance, or functioning of the mitotic spindle.
Deep pain thresholds in the distal limbs of healthy human subjects
Authors: Rolke R. , Campbell K. Andrews , Magerl W. , Treede R.‐D.
Published: May 2004

Pressure pain thresholds (PPTs) in distal limbs have been under‐investigated despite their potential clinical importance. Therefore, we compared PPTs over nail bed, bony prominences, and muscle in distal parts of upper and lower limbs. We investigated 12 healthy subjects using three handheld devices: a spring‐loaded, analogue pressure threshold meter (PTM) with two operating ranges, and an electronic Algometer. PPTs were determined with three series of ascending stimulus intensities with a ramp of about 50 kPa/s. PPTs were normally distributed in logarithmic space. PPTs over different tissues varied significantly (ANOVA,p<0.001): mean thresholds and 95% confidence intervals were 615 kPa (266–1424 kPa) over the nail bed, 581 kPa (271–1245 kPa) over bony prominences, and 520 kPa (246–1100 kPa) over muscles. PPTs on the foot were higher than on the hand (ANOVA,p<0.01), except over muscles. PPTs were significantly lower with the Algometer than with PTMs (ANOVA,p<0.01); again these differences were least when testing over muscle. There was no significant right‐left difference (ANOVA,p=0.33). In spite of considerable variability across subjects, reproducibility within subjects was high (correlation coefficients > 0.90). For within‐subject comparisons, threshold elevations beyond 33–43% would be abnormal (95% confidence intervals), whereas only deviations from the group mean by at least a factor of two would be abnormal with respect to absolute normative values. PPTs over distal muscles were comparable to published values on proximal limb and trunk muscles. These findings suggest that pressure pain testing over distal muscles may be a sensitive test for deep pain sensitivity and that the simple and less expensive devices are sufficient for testing this tissue type. Intra‐individual site‐to‐site comparisons will be more sensitive than absolute normative values.
BOF: a novel family of bacterial OB‐fold proteins
Authors: Ginalski Krzysztof , Kinch Lisa , Rychlewski Leszek , Grishin Nick V.
Published: May 2004

Using top‐of‐the‐line fold recognition methods, we assigned an oligonucleotide/oligosaccharide‐binding (OB)‐fold structure to a family of previously uncharacterized hypothetical proteins from several bacterial genomes. This novel family of bacterial OB‐fold (BOF) proteins present in a number of pathogenic strains encompasses sequences of unknown function from DUF388 (in Pfam database) and COG3111. The BOF proteins can be linked evolutionarily to other members of the OB‐fold nucleic acid‐binding superfamily (anticodon‐binding and single strand DNA‐binding domains), although they probably lack nucleic acid‐binding properties as implied by the analysis of the potential binding site. The presence of conserved N‐terminal predicted signal peptide indicates that BOF family members localize in the periplasm where they may function to bind proteins, small molecules, or other typical OB‐fold ligands. As hypothesized for the distantly related OB‐fold containing bacterial enterotoxins, the loss of nucleotide‐binding function and the rapid evolution of the BOF ligand‐binding site may be associated with the presence of BOF proteins in mobile genetic elements and their potential role in bacterial pathogenicity.
A modelling study of the influence of environment and food supply on survival of Crassostrea gigas larvae
Authors: Hofmann Eileen E , Powell Eric N , Bochenek Eleanor A , Klinck John M
Published: May 2004

A biochemically based model was developed to simulate the growth, development, and metamorphosis of larvae of the Pacific oyster (Crassostrea gigas). The unique characteristics of the model are that it: (1) defines larvae in terms of their protein, neutral lipid, polar lipid, carbohydrate, and ash content; (2) tracks weight separately from length to follow larval condition; and (3) includes genetic variation in growth efficiency and egg quality to better simulate cohort population dynamics. The model includes parameterizations for filtration, ingestion, and respiration, which determine larval growth rate, and processes controlling larval mortality and metamorphosis. Changes in larval tissue composition occur as the larva grows and in response to the biochemical composition of the food.

Simulations of larval growth indicate that departures of temperature, salinity, or food content from optimum levels reduce larval cohort survival, either because of metabolic constraints that result in death, unsuccessful metamorphosis, or increased predation resulting from increased larval lifespan. Temperatures and salinities near optimal values improve larval survival at low food concentration by increasing ingestion rate or growth efficiency. Also, survival at a given food concentration can vary widely depending on food composition, which determines food quality. The simulations suggest that the ratio of carbohydrate + lipid-to-protein may best describe the overall food quality, with optimal food compositions being characterized by ratios near 1.2 to 1.4 over a range of food concentrations. In contrast, food compositions containing too much or too little protein reduce larval survival, even at saturating food concentrations.

In simulations emphasizing genetic variability within the cohort, larvae with high growth efficiency originating from large eggs out-perform other egg quality–growth efficiency combinations over a wide range of temperature, salinity, and food contents. As a consequence, suboptimal temperature, salinity, or food content compresses genetic variation by uniformly favouring larvae from large eggs with a high growth efficiency. However, the larval survival obtained from simulations that use a range of food qualities is representative of a much broader range of genetic types. Thus, the simulations support the supposition that food quality is an important variable controlling the survival and genetic variability of C. gigas larval cohorts.
Elective vs. conservative management of ovarian tumors in pregnancy
Authors: Lee G.S.R. , Hur S.Y. , Shin J.C. , Kim S.P. , Kim S.J.
Published: May 2004

Objectives: To determine optimal management of the ovarian tumors in pregnancy. Methods: This study included 89 cases of the ovarian tumor in pregnancy that required surgery at Holy Family hospital of the Catholic University from January, 1990 to December, 2001. Among 89 cases, 36 and 53 were emergency and elective surgery, respectively. Student's t‐test and the χ2‐test were used for statistical analysis and a P‐value of <0.05 was considered statistically significant. Results: The most common size of torsion of ovarian tumors during pregnancy was 6–10 cm and the incidence was the most frequent during the first trimester of pregnancy. The incidence of preterm delivery (<37 weeks) was higher in emergency surgery, but there was no difference in the gestational age at delivery, also no difference in the birth weight or the method of delivery. Conclusions: Although surgery for ovarian tumors in pregnancy is delayed until the onset of symptoms, adverse pregnancy outcome is not worsened when compared with that after elective surgery. We propose that conservative management would be used in optimal management of pregnant women with ovarian tumors.
Arbeits- und Organisationspsychologie - Wo bleibt der Anwendungsbezug?
Authors: von Rosenstiel Lutz
Published: May 2004

Zusammenfassung. Im Folgenden wird die Situation der Arbeits- und Organisationspsychologie als psychologisches Anwendungsfach in Deutschland kritisch diskutiert. Anknüpfend an diese Situationsbeschreibung werden Vorschläge präsentiert, wie der Praxisbezug des Faches bildungs- und forschungspolitisch für die Zukunft erhalten und verbessert werden kann.
Ridge segmentation and the magnetic structure of the Southwest Indian Ridge (at 50°30′E, 55°30′E and 66°20′E): Implications for magmatic processes at ultraslow‐spreading centers
Authors: Sauter Daniel , Carton Hélène , Mendel Véronique , Munschy Marc , Rommevaux‐Jestin Céline , Schott Jean‐Jacques , Whitechurch Hubert
Published: May 2004

The aim of this paper is to investigate the relationships between the segmentation and the magnetic structure of the ultraslow‐spreading Southwest Indian Ridge. Contrary to faster spreading ridges, magnetization usually decreases from high values along the neovolcanic axis to low values in the nontransform discontinuities. There is a direct correlation between the deepening of the axial valley and the decrease of the magnetization from the neovolcanic axis toward the deepest parts of the axial discontinuities. We suggest that less frequent eruptions as the distance from the segment center and the length of these discontinuities increase, result in thinner extrusive lavas and thus control the along‐axis magnetization variations by thinning the magnetic source layer. A unique segment centered at 50°28′E shows a marked low magnetization anomaly at its center similarly to the segments of the slow‐spreading Mid‐Atlantic Ridge. We suggest that in this segment both the mantle temperature and the magmatic activity are high enough for the lavas not to be highly fractionated. A higher rate of melt production to the west of Gallieni transform fault may have created some form of reservoir where mixing of melts occurs and where crystalline fractionation is low producing low‐magnetization lavas. To the east, magma chambers may be smaller with cooler mantle temperatures resulting in restricted mixing and significant fractionation which may lead to relatively high intensity magnetization lavas. Finally, we propose that serpentinization of peridotites has no significant contribution to the variation of the magnetization along the axial valley. Off‐axis, in thin crust areas, upper mantle rocks may become progressively more altered, as distance from the axis increases. The strong faulting and alteration of a thin basaltic cap and underlying upper mantle rocks can produce the disappearance of the magnetic reversal pattern and the increase of the magnetization which is observed along the traces of the largest amagmatic discontinuities. By contrast, in thicker crust areas, the upper mantle rocks are shielded from the alteration and the serpentinization process may be delayed resulting, as on the Mid‐Atlantic Ridge, in slightly more positive magnetization values along the traces of axial discontinuities, regardless of polarity.
Nitrogen systematics and gas fluxes of subduction zones: Insights from Costa Rica arc volatiles
Authors: Zimmer Mindy M. , Fischer Tobias P. , Hilton David R. , Alvarado Guillermo E. , Sharp Zachary D. , Walker James A.
Published: May 2004

Volcanic gases are a powerful tool for assessing magmatic processes in subduction zones. We report gas chemistry and nitrogen isotope compositions of fumaroles, bubbling springs, and geothermal wells from the Costa Rican segment of the Central American volcanic segment (CAVS), and new correlation spectroscopy (COSPEC) SO2 flux measurements of Poás and Arenal volcanoes. N2/He ratios (100–8,250) and nitrogen isotope compositions (δ15N = −3.02 to +1.69‰) of Costa Rica volatiles are consistent with sources ranging from typical arc‐type end‐members, with nitrogen addition from the subducting slab, to MORB end‐member, having experienced no slab modification. Overall, nitrogen‐helium chemistry of Costa Rican material indicates a diminished slab contribution versus other locations along the arc (e.g., Nicaragua and Guatemala). We use SO2 flux measurements of Poás and Arenal (1.80*105 ± 4.00*104 and 8.30*103 ± 4.00*103 kg/day, respectively, or 1.30*105 ± 6.25*104 and 2.81*106 ± 6.25*105 mol/day, respectively) to extrapolate a SO2 flux for the Costa Rica segment of 1.09*109 mol/day. Using CO2/St (St = total sulfur) of 2.7 and 5.9, we calculate CO2 fluxes of 1.88*108 and 4.11*108 kg/yr, respectively (2.94*109 and 6.42*109 mol/yr, respectively). Other volatile fluxes (N2, He, H2, Ar, HCl, and H2O) are calculated using CO2/St and regional gas chemistry. For Costa Rica, the output/input ratios of nitrogen are less than unity (0.03 to 0.06 for CO2/St of 2.7 and 5.9, respectively), suggesting more N is subducted than released in the subarc, possibly resulting from sediment offscraping, forearc devolatilization, limited fluid availability in the subarc, or subduction past the subarc.
Midlatitude sub‐auroral ionospheric small scale structure during a magnetic storm
Authors: Keskinen M. J. , Basu S. , Basu Santimay
Published: May 2004

We develop a model for small scale structure in the midlatitude sub‐auroral polarization stream (SAPS)‐driven density trough ionosphere during a magnetic storm. We include the effects of ring current precipitation, parallel currents, rapid subauroral ion drifts, storm‐induced neutral winds, ion temperature and density gradients. We find that ionospheric density, electric field, ion and electron temperature irregularities can be driven in the stormtime SAPS‐driven density trough (1) wall region from the ion temperature gradient convective instability, which is driven by density and ion temperature gradients, in concert with the gradient‐drift instability and (2) central region from an ion frictional heating instability which is driven by strong ion convection.
Cluster measurements of rapidly moving sources of ELF/VLF chorus
Authors: Inan U. S. , Platino M. , Bell T. F. , Gurnett D. A. , Pickett J. S.
Published: May 2004

The first simultaneous measurements of discrete chorus emissions on multiple spacecraft, realized in the context of the Cluster mission, revealed a rather unexpected frequency difference of around 1 kHz between nearly identical discrete elements observed on different spacecraft [Gurnett et al., 2001]. This frequency difference is interpreted herein as a natural outcome of the dependence of the whistler‐mode refractive index on the wave normal angle between the wave vector k and the static magnetic field B0 and the rapid motion of highly localized source region(s) of chorus of 400 km to 1700 km in extent along the field line, but only less than 100 km transverse to the magnetic field, and moving at speeds of 20,000 km/s to 25,000 km/s. Wave packets emanating from the localized regions propagate to two spacecraft at different wave normal angles, and are observed at different frequencies due to the differential Doppler shift between the two spacecraft. These differences in frequency, as well as the different times of arrival of the similar emissions at the different spacecraft, provide a unique opportunity to estimate the source characteristics, using a model involving rapidly moving sources traveling at speeds comparable to the parallel resonant velocity of counterstreaming electrons moving along the Earth's magnetic field lines. We report the determination of chorus emission source region motion for two different cases observed during 2000–2001, where these differences in frequency were readily observable due to the relatively large separation of the Cluster spacecraft. We also report a case in 2002 where the spacecraft separations were smaller, so that these frequency differences were not as evident but nevertheless measurable. In general, our results provide the first experimental evidence that the sources that generate the discrete chorus emissions are in rapid motion.
Radiance and flux simulations for mineral dust aerosols: Assessing the error due to using spherical or spheroidal model particles
Authors: Kahnert M. , Kylling A.
Published: May 2004

The use of simple model particles to represent mineral dust aerosols may introduce errors in radiative transfer calculation. A modeling study has been performed to assess these errors. At a wavelength of 550 nm it is found that spheres can cause errors in the diffuse spectral radiance between −18% and 26% at the bottom of the atmosphere (BOA) and between −16% and 115% at the top of the atmosphere (TOA). These errors correspond to an uncertainty in the extinction optical depth τ between 0.7τ and 1.5τ (BOA) and (disregarding extreme errors in the solar nadir direction) between 0.5τ and 2τ (TOA). When using spheroidal model particles, the spectral radiance errors are reduced by roughly a factor of 2 (BOA) and are almost zero at the TOA over a large angular range. For a latitude of 20° we find, as a conservative estimate, that spherical model particles overestimate the yearly averaged TOA spectral net flux by almost 10 W m−2 nm−1. This error is mainly due to the misrepresentation of the aerosol phase function by the spheres. A rough estimate using Mie calculations indicates that this error is 5 times higher than (50% of) the error due to the uncertainty in the real (imaginary) part of the refractive index. Spheroids, on the other hand, only differ by 1.3 W m−2 nm−1 from the reference case. This indicates that using spherical model particles may cause significant positive errors in radiative forcing simulations for dust aerosols and that using simple spheroids can substantially improve the results.
Water potential in nonrigid unsaturated soil‐water medium
Authors: Braudeau Erik , Mohtar Rabi H.
Published: May 2004

This paper presents a development of water potential functions for a dual porosity nonrigid aggregated soil medium defined and characterized by its characteristic shrinkage curve. Fractal and thermodynamic approaches to modeling soil water potential are evaluated using simultaneous and continuously measured soil shrinkage and tensiometric curves on a standard laboratory soil sample. Water potential relationships are developed and analyzed for five Ivory Cost soils with clay content ranging from 10 to 50%. Analysis of modeled and observed results showed that the tensiometric curve, for its entire range of measurement, is directly linked to the interped water pool. The tensiometric curve, which is a function of the interped water pool, was modeled using both the fractal and the thermodynamical equations. Fits to the measured tensiometric curves were very well. This study demonstrates the link between the tensiometric curve with some of the pedostructure (soil‐water medium) variables and parameters determined by the shrinkage curve, which leads to physically based equations of soil water potential. An interpretation of the origin of the swelling pressure inside and outside the primary peds and of the resulting suction pressure in unsaturated aggregated soils is proposed and discussed. This interpretation explains the link between the generalized Low's [1979] equation for the thermodynamic properties of the hydration layers of water surrounding particles in primary peds and the equations given by Berezin et al. [1983] for the swelling and the suction pressures in unsaturated aggregates.
Photosynthetic Acclimation to Simultaneous and Interacting Environmental Stresses Along Natural Light Gradients: Optimality and Constraints
Authors: Niinemets ü. , Valladares F.
Published: May 2004

Abstract: There is a strong natural light gradient from the top to the bottom in plant canopies and along gap‐understorey continua. Leaf structure and photosynthetic capacities change close to proportionally along these gradients, leading to maximisation of whole canopy photosynthesis. However, other environmental factors also vary within the light gradients in a correlative manner. Specifically, the leaves exposed to higher irradiance suffer from more severe heat, water, and photoinhibition stresses. Research in tree canopies and across gap‐understorey gradients demonstrates that plants have a large potential to acclimate to interacting environmental limitations. The optimum temperature for photosynthetic electron transport increases with increasing growth irradiance in the canopy, improving the resistance of photosynthetic apparatus to heat stress. Stomatal constraints on photosynthesis are also larger at higher irradiance because the leaves at greater evaporative demands regulate water use more efficiently. Furthermore, upper canopy leaves are more rigid and have lower leaf osmotic potentials to improve water extraction from drying soil. The current review highlights that such an array of complex interactions significantly modifies the potential and realized whole canopy photosynthetic productivity, but also that the interactive effects cannot be simply predicted as composites of additive partial environmental stresses. We hypothesize that plant photosynthetic capacities deviate from the theoretical optimum values because of the interacting stresses in plant canopies and evolutionary trade‐offs between leaf‐ and canopy‐level plastic adjustments in light capture and use.
Engineering Plants for Elevated CO2: A Relationship between Starch Degradation and Sugar Sensing
Authors: Sharkey T. D. , Laporte M. , Lu Y. , Weise S. , Weber A. P. M.
Published: May 2004

Abstract: In the future, plants will have additional CO2 for photosynthesis. However, plants do not take maximal advantage of this additional CO2 and it has been hypothesized that end product synthesis limitations and sugar sensing mechanisms are important in regulating plant responses to increasing CO2. Attempts to increase end product synthesis capacity by engineering increased sucrose‐phosphate synthase activity have been generally, but not universally, successful. It was found that plants benefited from a two‐ to three‐fold increase in SPS activity but a 10‐fold increase did not increase yield. Despite the success in increasing yield, increasing SPS did not increase photosynthesis. However, carbon export from chloroplasts was increased during the day and reduced at night (when starch provides carbon for sucrose synthesis. We develop here a hypothesis that starch degradation is closely sensed by hexokinase because a newly discovered pathway required for starch to sucrose conversion that involves maltose is one of few metabolic pathways that requires hexokinase activity.
Thermoluminescence Study of Photosystem II Activity in Haberlea rhodopensis and Spinach Leaves During Desiccation
Authors: Peeva V. , Maslenkova L.
Published: May 2004

Abstract: Thermoluminescence glow curve parameters were used to access the functional features of PS II in the Balkan endemic Haberlea rhodopensis. This representative of the higher desiccation‐tolerant plants is unique for the European flora. An unusual high temperature of TL emission from Haberlea leaves after excitation by one flash at 5 °C was observed. The position of the main TL B band (S2QB‐) was at 45 ‐ 47 °C, while this temperature was 30 ‐ 32 °C in drought‐sensitive mesophytic spinach. Consistent with the up‐shift in TL emission, the lifetime of the S2 state was also increased, showing a stabilization of charge storage in PS II complex in this resurrection plant. In addition, a part of PS II centres was less susceptible to DCMU. We consider the observed unusual TL characteristics of Haberlea rhodopensis reflect some structural modifications in PS II (especially in D1 protein), which could be related to the desiccation tolerance of this plant. This suggestion was supported by the different manner in which dehydration affected the TL properties in desiccation‐tolerant Haberlea and desiccation‐sensitive spinach plants.
Development of Leaf Photosynthetic Parameters in Betula pendula Roth Leaves: Correlations with Photosystem I Density
Authors: Eichelmann H. , Oja V. , Rasulov B. , Padu E. , Bichele I. , Pettai H. , Niinemets ü. , Laisk A.
Published: May 2004

Abstract: The global modelling of photosynthesis is based on exact knowledge of the leaf photosynthetic machinery. The capacities of partial reactions of leaf photosynthesis develop at different rates, but it is not clear how the development of photoreactions and the Calvin cycle are co‐ordinated. We investigated the development of foliar photosynthesis in the temperate deciduous tree Betula pendula Roth. using a unique integrated optical/gas exchange methodology that allows simultaneous estimation of photosystem I and II (PS I and PS II) densities per leaf area, interphotosystem electron transport activities, and ribulose‐1,5‐bisphosphate carboxylase/oxygenase (Rubisco) kinetic properties. We combined these measurements with in vitro determinations of Rubisco, soluble protein and chlorophyll contents. We observed a strong increase in leaf photosynthetic capacity in developing leaves per leaf area, as well as per dry mass, that was paralleled by accumulation of leaf Rubisco. Enhanced mesophyll conductance was the outcome of increased carboxylation capacity and increased CO2 diffusion conductance. However, Rubisco was only partly activated in the leaves, according to in vivo measurements of Rubisco kinetics. The amount of active Rubisco increased in proportion with development of PS I, probably through a direct link between Rubisco activase and PS I electron transport. Since the kinetics for post‐illumination P700 re‐reduction did not change, the synthesis of cytochrome b6f complex was also proportional to PS I. The synthesis of PS II began later and continued for several days after reaching the full PS I activity, but leaf chlorophyll was shared equally between the photosystems. Due to this, the antenna of PS II was very large and not optimally organized, leading to greater losses of excitation and lower quantum yields in young leaves. We conclude that co‐ordinated development of leaf photosynthesis is regulated at the level of PS I with subordinated changes in PS II content and Rubisco activation.
Water Shortage Affects the Water and Nitrogen Balance in Central European Beech Forests
Authors: Geβler A. , Keitel C. , Nahm M. , Rennenberg H.
Published: May 2004

Abstract: Whilst forest policy promotes cultivation and regeneration of beech dominated forest ecosystems, beech itself is a highly drought sensitive tree species likely to suffer from the climatic conditions prognosticated for the current century. Taking advantage of model ecosystems with cool‐moist and warm‐dry local climate, the latter assumed to be representative for future climatic conditions, the effects of climate and silvicultural treatment (different thinning regimes) on water status, nitrogen balance and growth parameters of adult beech trees and beech regeneration in the understorey were assessed. In addition, validation experiments with beech seedlings were carried out under controlled conditions, mainly in order to assess the effect of drought on the competitive abilities of beech. As measures of water availability xylem flow, shoot water potential, stomatal conductance as well as δ13C and δ18O in different tissues (leaves, phloem, wood) were analysed. For the assessment of nitrogen balance we determined the uptake of inorganic nitrogen by the roots as well as total N content and soluble N compounds in different tissues of adult and young trees. Retrospective and current analysis of δ13C, growth and meteorological parameters revealed that beech growing under warm‐dry climatic conditions were impaired in growth and water balance during periods with low rain‐fall. Thinning affected water, N balance and growth mostly of young beech, but in a different way under different local climatic conditions. Under cool, moist conditions, representative for the current climatic and edaphic conditions in beech forests of Central Europe, thinning improves nutrient and water status consistent to published literature and long‐term experience of forest practitioners. However, beech regeneration was impaired as a result of thinning at higher temperatures and under reduced water availability, as expected in future climate.
Water Sources and Water‐Use Efficiency in Mediterranean Coastal Dune Vegetation
Authors: Alessio G. A. , de Lillis M. , Brugnoli E. , Lauteri M.
Published: May 2004

Abstract: In coastal environments plants have to cope with various water sources: rainwater, water table, seawater, and mixtures. These are usually characterized by different isotopic signatures (18O/16O and D/H ratios). Xylem water reflects the isotopic compositions of the water sources. Additionally, water‐use efficiency (WUE) can be assessed with carbon isotope discrimination (Δ) analyses. Gas exchange, Δ of leaf dry matter, and isotopic composition (δ18O) of xylem water were measured from June to August 2001 in herbaceous perennials of mobile dunes (Ammophila littoralis, Elymus farctus) and sclerophyllous shrubs and climbers (Arbutus unedo, Pistacia lentiscus, Phillyrea angustifolia, Qercus ilex, Juniperus oxycedrus, Smilax aspera) of consolidated dunes. Assimilation rates were rather low and did not show clear seasonal patterns, possibly due to limited precipitation and generally low values of stomatal conductance. The lowest values were shown in S. aspera. Different physiological patterns were found, on the basis of δ18O and Δ analyses. Values of δ18O of xylem water of phanerophytes were remarkably constant and matched those of the water table, indicating dependence on a reliable water source; values of Δ were relatively high, indicating low intrinsic WUE, with the exception of J. oxycedrus. Surprisingly, very high δ18O values were found for the xylem water from S. aspera in August. This suggests retrodiffusion of leaf water to xylem sap in the stem or direct uptake of water by leaves or stems, owing to dew or fog occurrence. Low Δ values indicated high WUE in S. aspera. Contrasting strategies were shown by the species of mobile dunes: E. farctus relied on superficial water and exhibited low WUE, accordingly to its therophyte‐like vegetative cycle; on the contrary, A. littoralis used deeper water sources, showing higher WUE in relation to its long‐lasting vegetative habit.