bluuebunny/crossref_metadata_2025 huggingface dataset:
PUVA‐induced apoptosis involves mitochondrial dysfunction caused by the opening of the permeability transition pore
Authors: Canton Marcella , Caffieri Sergio , Dall'Acqua Francesco , Di Lisa Fabio
Published: September 2002

The mechanism of cell death was investigated in Jurkat cells exposed to the combination of psoralen and UVA irradiation (PUVA). Apoptosis was by far prevailing over necrosis and involved mitochondrial dysfunction. The collapse of mitochondrial membrane potential, appears to be caused by the opening of the mitochondrial permeability transition pore since its inhibitor, cyclosporin A, prevented mitochondrial dysfunction and largely attenuated apoptosis. Apoptosis also occurred in cells treated with the photoproducts generated by irradiating psoralen in vitro with an oxygen‐dependent process. Thus, the involvement of reactive oxygen species in the onset of PUVA‐induced apoptosis appears mostly related to psoralen photooxidation.
Flavinylation of the precursor of mitochondrial dimethylglycine dehydrogenase by intact and solubilised mitochondria
Authors: Brizio Carmen , Barile Maria , Brandsch Roderich
Published: September 2002

The flavinylation and the presequence processing of the mitochondrial matrix enzyme dimethylglycine dehydrogenase (Me2GlyDH) were investigated with the reticulocyte lysate translated precursor (pMe2GlyDH) added to solubilised mitoplasts of rat liver mitochondria. The flavinylation of pMe2GlyDH was strictly dependent on the addition of mitochondrial protein(s), among which the mitochondrial flavinylation stimulating factor [Brizio C., et al. (2000) Eur. J. Biochem 267, 4346–4354], that actively promotes holo‐Me2GlyDH formation. The precursor processing, that accompanies the biogenesis of the enzyme, was not required to allow the flavinylation to proceed. The comparison of the time course of the flavinylation and the processing of pMe2GlyDH demonstrated that the covalent attachment of the flavin moiety preceded the presequence processing by mitochondrial processing peptidase.
Identification of the E2‐binding residues in the N‐terminal domain of E1 of a prokaryotic pyruvate dehydrogenase complex
Authors: Hengeveld Annechien F , de Kok Aart
Published: September 2002

Pyruvate dehydrogenase (E1p) is one of the components of the pyruvate dehydrogenase multienzyme complex (PDHC). Previously, it was shown that the N‐terminal domain of E1p is involved in its binding to the core component (E2p) of PDHC. We constructed point mutations in this domain (D17Q, D17R, E20Q, E20R, D24Q and D24R) to identify the specific residues involved in these interactions. Kinetic and binding studies show that D17 is essential for the binding of E1p to E2p. D24 is involved in the binding, but not essential, whereas E20 is not involved. None of the mutations affects the folding or dimerisation of E1p.
Adjuvant chemotherapy in stage I uterine endometrial carcinoma
Authors: Hirai M. , Hirono M. , Oosaki T. , Hayashi Y. , Yoshihara T. , Itami M.
Published: September 2002

Objective: We have assessed prognostic factors and the efficacy of adjuvant chemotherapy in stage I uterine endometrial carcinoma. Methods: 251 primary surgically treated stage I patients were studied. Prognostic factors were evaluated and 5‐year and 10‐year survival rates were compared in patients with lymph‐vascular space invasion to investigate whether adjuvant chemotherapy improves survival. Results: The overall 5‐year and 10‐year survival rates were 94% and 93%. Multivariate analysis indicates that lymph‐vascular space invasion is the most significant prognostic factor in both 5‐ and 10‐year survival rates (P<0.001 at both times) and stage/depth of invasion is significant for the 10‐year survival rate (P=0.04). Of 54 patients with lymph‐vascular space invasion, statistically significant differences were observed in 10‐year survival rate (P=0.02) between patients who had surgery followed by adjuvant chemotherapy (n=23) and patients who had surgery alone (n=31). Toxicities were mild to moderate (30%). Conclusions: The clinical importance of lymph‐vascular space invasion and the efficacy of adjuvant chemotherapy were confirmed. This observation warrants a larger comparative study with adjuvant chemotherapy.
Post‐partum maternity ‘blues’ as a reflection of newborn nursing care in Japan
Authors: Sakumoto K. , Masamoto H. , Kanazawa K.
Published: September 2002

Objectives: To investigate the prevalence of post‐partum ‘blues’ in mothers whose babies are cared for in a newborn nursery, compared with mothers providing rooming‐in care. Methods: Japanese normal primiparous women were prospectively studied from 1998 to 1999. The newborns of these mothers were managed in the newborn nursery or by rooming‐in care. To diagnose maternity ‘blues’ and ‘depression’, the Stein's Questionnaire and the Edinburgh Postnatal Depression Scale were used. Results: Ninety‐seven and 93 women were managed by newborn nursery care and by rooming‐in care, respectively. Of these women, a total of 181 women were considered for analysis. ‘Blues’ was noted in 31 of 92 mothers (33.7%) receiving newborn nursery care and in 18 of 89 (20.2%) receiving rooming‐in care with a significant difference (P<0.05), and in 49 of 181 (27.1%) as a whole. The daily Stein's scores changed significantly during the 10 days post‐partum in each group (P<0.0001). Post‐partum ‘depression’ was observed in three mothers (3.4%) in the newborn nursery care group and in four (4.8%) of the rooming‐in care group, not a significant difference, and in seven (4.1%) as a whole. Conclusion: Maternity ‘blues’ is experienced by 25% or more of Japanese primiparous women delivering healthy babies via uncomplicated delivery. The system of newborn nursery infant care may be a potential causal factor for maternity ‘blues’, although it should be confirmed by a prospective randomized trial.
Induction of labor with prostaglandin E2 vaginal tablets in parous and grandmultiparous patients with previous cesarean section
Authors: Sobande A.A. , Albar H.
Published: September 2002

Objectives: To compare the outcome of induction of labor with prostaglandin E2 vaginal tablets between lower parity (parity 1–5) and grandmultiparous (parity >5) patients with a history of one previous lower segment cesarean section. Methods: A prospective study of 113 patients conducted at King Faisal Military Hospital, Khamis Mushayt, Saudi Arabia during a 5‐year period spanning January1995 to December 1999. Results: There were no statistically significant differences in the two groups regarding mean maternal age, dose of prostaglandin used, gestation at delivery, mean birth weight, P>0.05. Syntocinon augmentation was used in 16 (21.9%) of the lower parity patients compared with 8 (20.0%) in the grandmultiparas but this was not statistically significant, (P=0.677). However, there was a statistically significant difference in the cesarean section rate between the two groups, P=0.019. Although no cases of uterine hyperstimulation were recorded, there was one rupture of the uterus in each of the two groups of patients; 1.36% and 2.5%, respectively, but this was not statistically significant, P=1.000. Conclusions: The complications of induction of labor with prostaglandin E2 vaginal tablets in grandmultiparous patients with previous cesarean section were similar to those with lower parity but the cesarean section rate was significantly higher. However, larger studies are needed for validation.
Expression and developmental regulation of gap junction connexins cx26, cx32, cx43 and cx45 in the rat midbrain‐floor
Authors: Leung Doreen Siu Yi , Unsicker Klaus , Reuss Bernhard
Published: September 2002

Connexins (cx) constitute a family of transmembrane proteins that form gap junction channels allowing metabolic and electrical coupling of cellular networks. Initial studies on the expression of cx in the developing brain have suggested that cx may undergo dynamic changes and may possibly be implicated in synchronizing development and differentiation of neural progenitor cells and young neurons. We have investigated expression of cx26, cx32, cx43, and cx45 in the midbrain floor, where nigrostriatal dopaminergic neurons originate and differentiate. This neuron population is of major importance in regulating motor‐functions. Semiquantitative reverse transcriptase‐polymerase chain reaction (RT‐PCR) revealed low levels of cx26‐mRNA in the midbrain floor at E12, which gradually increased during pre‐ and postnatal development, reaching a maximum in the adult. Cx32‐mRNA‐levels reached a first peak at E16, and showed highest levels in adulthood. Cx43 was highly expressed at E12, decreased until E18, and subsequently increased again until adulthood. Cx45 mRNA was prominent at all developmental ages, but slightly decreased after the first postnatal week. Double‐labeling for the dopaminergic neuronal marker tyrosine hydroxylase (TH), and cx‐immunoreactivities (ir) evaluated by quantitative confocal laser microscopy revealed both distinct and similar developmental patterns for the individual cx investigated. Cx26 was highest at E14, decreased towards birth, and subsequently increased again reaching about 50% of the E14 level in the adult. Cx32‐ir peaked at E16 and dropped to low levels after birth. Cx43‐ir was highest at E12, decreased sharply at E14, reached its lowest levels at birth, but modestly increased again afterwards. Cx45‐ir showed a biphasic pattern, with two prominent peaks at E12 and E18, followed by a massive postnatal decrease. Taken together, our results reveal that expression and ir of cx in the midbrain floor and dopaminergic neurons, respectively, follow cx‐type specific patterns that temporally coincide with important steps of midbrain morphogenesis, as e.g. progenitor cell formation and migration (E12), early differentiation (E14‐16), target encounter (E16‐18) and postnatal functional maturation of the nigrostriatal system.
A Century of International Trade Unionism
Authors: Pasture Patrick
Published: September 2002

The International Confederation of Free Trade Unions. [By] Anthony Carew, Michel Dreyfus, Geert Van Goethem [and] Rebecca Gumbrell-McCormick. Marcel van der Linden (Ed.) [International and Comparative Social History, vol. 3.] Peter Lang, Bern [etc.] 2000. 624 pp. S.fr. 117.00; DM 147.00; S 975.00.
TRENDS AND DIFFERENTIALS IN MENARCHEAL AGE IN CHINA
Authors: WANG DUOLAO , MURPHY MICHAEL
Published: September 2002

This study examines trends in menarcheal age of women born in China between 1950 and 1973, and explores the impact of relevant social background characteristics on the timing of first menarche. Data on recalled ages of menarche collected in the 1988 Chinese Two-per-Thousand Fertility Survey are used in a linear regression model where the covariates are transformed with the help of an Alternating Conditional Expectation (ACE) algorithm. The results indicate that a trend towards early menarche has evolved in China during recent decades. The pattern of early menarche is especially pronounced among women residing in urban areas, and those who are better educated.
Reply to van Donge
Authors: Ponte Stefano
Published: September 2002

Van Donge's comment on my reassessment of agrarian change on the Uluguru Mountains, Tanzania, raises a number of issues that go beyond the specificities of the location under scrutiny. Before dealing with these, however, let me restate my argument, which van Donge has reconstructed only selectively. In my article (Ponte 2001a), I argued that rural households are not ‘trapped in decline’ on the Uluguru Mountains, as depicted in previous literature. Although agriculture is not going through an easy transition in the area, and some options are becoming more limited, others are being more skilfully utilised. On the Uluguru Mountains, land scarcity is the main feature of agriculture; deforestation and soil erosion are major problems; and inputs have become increasingly expensive. Under these circumstances, the main ways households can improve their quality of life – short of leaving the area altogether, and in addition to relying on remittances from outside – are to expand land cultivated in other locations, to experiment with alternative farming systems, and to increase non-farm incomes. I observed that Uluguru households were doing all of these in the mid-1990s, and that their income levels and housing characteristics had improved. This was intriguing and challenging to me, since farmers' adaptations to changing markets had not led to higher incomes in other areas that I had researched in Tanzania. Finally, I suggested that economic diversification can play an important role in improving rural livelihoods, but that this process is more likely to take place in locations with well-established economic ties and relatively good access to major markets.

Van Donge has a variety of problems with my argument. These can be grouped around three main themes: (1) issues of methodology; (2) a perceived misunderstanding of his argument; and (3) the impact of liberalisation. Due to space limitations, in my reply to van Donge I deal with these larger themes. A more detailed response covering specific evidence and technicalities is available from this author and has been sent to van Donge.
Comparison between human and animal isolates of Shiga toxin-producing Escherichia coli O157 from Australia
Authors: FEGAN N. , DESMARCHELIER P.
Published: September 2002

There is very little human disease associated with enterohaemorrhagic Escherichia coli O157 in Australia even though these organisms are present in the animal population. A group of Australian isolates of E. coli O157:H7 and O157:H- from human and animal sources were tested for the presence of virulence markers and compared by XbaI DNA macrorestriction analysis using pulsed-field gel electrophoresis (PFGE). Each of 102 isolates tested contained the gene eae which encodes the E. coli attaching and effacing factor and all but one carried the enterohaemolysin gene, ehxA, found on the EHEC plasmid. The most common Shiga toxin gene carried was stx2c, either alone (16%) or in combination with stx1 (74%) or stx2 (3%). PFGE grouped the isolates based on H serotype and some clusters were source specific. Australian E. coli O157:H7 and H- isolates from human, animal and meat sources carry all the virulence markers associated with EHEC disease in humans therefore other factors must be responsible for the low rates of human infection in Australia.
The burden of Helicobacter pylori infection in England and Wales
Authors: VYSE A. J. , GAY N. J. , HESKETH L. M. , ANDREWS N. J. , MARSHALL B. , THOMAS H. I. J. , MORGAN-CAPNER P. , MILLER E.
Published: September 2002

The prevalence of active infection with Helicobacter pylori in the general population of England and Wales was estimated using high reactivity for specific IgG in serum ELISA as a marker. A total of 10118 anonymized residues of serum samples collected in 1986 and 1996 from persons aged 1–84 years were used. Estimated prevalence of active infection varied by region and was highest in London. Prevalence was related to decade of birth and increased from 4·3% in those born during the 1980s to 30% in those born before 1940. An estimated total of 7·5 million people living in England and Wales have an active infection and analysis by decade of birth showed no significant difference between samples collected in 1986 and 1996. These data suggest H. pylori infection is becoming less common, is acquired at an early age and is unlikely to be resolved unless suitable antimicrobial treatment is sought.
A Bronze Weight of Saʿîd b. ʿAbd al-Malik from Bet Shean/Baysân
Authors: Khamis Elias
Published: September 2002

This paper presents a unique bronze weight manufactured by the order of a little-known son of [ain]Abd al-Malik, who was governor of Jund Filastîn for a short period. The weight, of the Byzantine disc type, but bearing Arabic inscriptions, was found in the excavations carried out by the Institute of Archaeology of the Hebrew University of Jerusalem in 1990. It is discussed here in the context of other metal weights of the period which bear Arabic inscriptions but are of Byzantine form, and which sometimes also bear Byzantine symbols and Greek inscriptions.
Seasonal to interannual modes of sea level variability in the western Pacific and eastern Indian oceans
Authors: Potemra James T. , Lukas Roger
Published: September 2002

Almost six years of TOPEX/Poseidon altimeter data were analyzed to discern low frequency (monthly to interannual) variability in the region from the eastern Indian Ocean east to the dateline. An empirical orthogonal function (EOF) analysis shows that from September 1992 through April 1998 the dominant mode of sea level variability in the western Pacific/eastern Indian Ocean is on the ENSO time scale, and annual variability is secondary. The amplitude of the annual cycle becomes even less in the latter part of the time period (in the years prior to the 1997/98 El Niño event). The pattern that emerges on interannual time scales is one of western Pacific warm pool buildup (during non‐El Niño years) and discharge (during El Niño years). Mixed with these signals is a large amplitude signal in the eastern Indian Ocean, south of the equator (off the south coast of Sumatra), which has both annual and interannual variations associated with it. Harmonic analysis shows the annual cycle is dominated by Rossby waves in both the equatorial Pacific and at higher latitudes in the eastern Indian Ocean.
Aerosol‐Mediated Partitioning of Stratospheric Cly and NOy at Temperatures Above 200 K
Authors: Michelsen H. A. , Spivakovsky C. M. , Wofsy S. C.
Published: September 2002

Rates of aerosol‐mediated reactions involving inorganic halogen species are small but non‐negligible for moderate aerosol abundances at temperatures of 200–210 K. We have used a photochemical model to demonstrate that at these temperatures such reactions provide a significant sink for HCl. Gas‐phase production rates are slower for HCl than for ClNO3. The net result is preferential partitioning of Cly into [ClNO3] to compensate for the accelerated loss of [HCl]. Under such conditions, [HNO3] decreases in response to enhanced partitioning of NOy into [ClNO3]. The results indicate a high sensitivity and synergistic response of HCl, ClNO3, and HNO3 distributions to aerosol content and temperature.
Equatorial currents at 1000 m in the Atlantic Ocean
Authors: Molinari Robert L. , Garzoli Silvia L. , Schmitt Raymond W.
Published: September 2002

Twenty‐seven Profiling ALACE (PALACE) floats were deployed in the equatorial Atlantic during July–August 1997. The floats were ballasted to drift at 1000 m for 10 to 14 days, return to the surface while obtaining a temperature profile, transmit data via satellite, and then after one day return to 1000 m. One‐year float paths are now available. Floats deployed on the equator were launched into a deep westward jet. The jet extends some 1°–2° north of the equator, with eastward motion observed in floats to the north of 2°N. The equatorial current reverses in the central basin to the east in mid‐October and then back to the west in mid‐February. Flow to the north also reverses. The short space and time scales contrast with earlier work based on fewer floats that inferred space scales of some 5°–10° in latitude and time scales greater than one year. The new results are consistent with models that indicate that equatorial Rossby waves are the cause of the reversing currents.
High‐latitude ionospheric convection during strong interplanetary magnetic field By
Authors: Huang Chao‐Song , Sofko G. J. , Murr D. , Hughes W. J. , Moretto T.
Published: September 2002

An unusual high‐latitude ionospheric convection pattern was observed on March 23, 1995. The dayside ionospheric convection appeared as a clockwise merging convection cell focused at 84° magnetic latitude around 1200 MLT. No signature of the viscous convection cell in the afternoon sector was observed. The interplanetary magnetic field (IMF) conditions corresponding to the occurrence of the ionospheric convection were Bx ≈ 1 nT, By ≈ 10 nT, and Bz<0 (|Bz| ≪ By). We have compared our observations with statistical patterns and MHD numerical models for similar IMF conditions. It is found that the location of the convection cell focus in this event is at least two hours earlier than those previously observed and about 5 hours earlier than that predicted by the MHD model. The observations may have some significant implications on the antiparallel merging theory.
On thermocline ventilation of active and passive tracers
Authors: Liu Zhengyu , Shin Sang‐Ik
Published: September 2002

The ventilation propagation of temperature and passive tracer anomalies are compared in a numerical model. Although both anomalies tend to have pathways close to the mean ventilation flow, the temperature anomaly could have a slower propagation speed and a more complex spatial structure. The temperature propagation is better understood in terms of baroclinic planetary waves.
The heliospheric boundary response to large‐scale solar wind fluctuations: A gasdynamic model with pickup ions
Authors: Wang Chi , Belcher John W.
Published: September 2002

Observations show that the solar wind ram pressure has large‐scale fluctuations on the timescale of days to years. Such fluctuations will cause inward and outward motions of the heliospheric boundary, including the termination shock and the heliopause. A two‐dimensional time‐dependent hydrodynamic model for the interaction of the solar wind with the local interstellar medium, which includes the mutual interaction of the interstellar and solar wind plasma and the interstellar neutral hydrogen, is employed to study the changes in the global heliosphere brought about by both long‐term (for example, 11‐year solar cycle) and short‐term (for example, tens of days) variations in the solar wind. The inclusion of neutrals is found to reduce the amplitude of the boundary motion. The size of the excursions of the termination shock in response to the 11‐year solar cycle variation is about 13 AU per solar cycle in our calculation. The motion of the termination shock is asymmetric in time, that is, the termination shock moves outward faster than it moves inward, even though the 11‐year variation is applied as a sinusoidal change at the inner boundary. The concurrent excursions of the heliopause are found to be much smaller than those of the termination shock, and the heliospheric bow shock seems unaffected by the solar cycle pressure variations. The motion of the termination shock due to shorter period (180 days) fluctuations in the solar wind is much smaller (3 to 4 AU), and the heliopause has little response to such short‐term fluctuations. Possible crossing of the termination shock and the heliopause by the Voyager 1 spacecraft are discussed.
Combined Ulysses solar wind and SOHO coronal observations of several west limb coronal mass ejections
Authors: Funsten H. O. , Gosling J. T. , Riley P. , St. Cyr O. C. , Forsyth R. J. , Howard R. A. , Schwenn R.
Published: September 2002

From October 1996 to January 1997, Ulysses was situated roughly above the west limb of the Sun as observed from Earth at a heliocentric distance of about 4.6 AU and a latitude of about 25°. This presents the first opportunity to compare Solar and Heliospheric Observatory (SOHO) limb observations of coronal mass ejections (CMEs) directly with their solar wind counterparts far from the Sun using the Ulysses data. During this interval, large eruptive events were observed above the west limb of the Sun by the Large Angle Spectrometric Coronagraph (LASCO) on SOHO on October 5, November 28, and December 21–25, 1996. Using the combined plasma and magnetic field data from Ulysses, the October 5 event was clearly identified by several distinguishing signatures as a CME. The November 28 event was also identified as a CME that trailed fast ambient solar wind, although it was identified only by an extended interval of counterstreaming suprathermal electrons. The December 21 event was apparently characterized by a 6‐day interval of nearly radial field and a plasma rarefaction. For the numerous eruptive events observed by the LASCO coronagraph during December 23–25, Ulysses showed no distinct, individual CMEs, perhaps because of intermingling of two or more of the eruptive events. By mapping the Ulysses observations back in time to the Sun assuming a constant flow speed, we have identified intervals of plasma that were accelerated or decelerated between the LASCO and Ulysses observations.
A statistical study of ion beams and conics from the dayside ionosphere during different phases of a substorm
Authors: Øieroset M. , Yamauchi M. , Liszka L. , Christon S. P. , Hultqvist B.
Published: September 2002

The increase of upflowing ions from the dayside ionosphere during substorms has been investigated using Viking ion data and 1‐min values of the AE index. An automated algorithm using principal component analysis has been used to categorize and classify the upflowing ions (UFIs), that is, beams, conies, and hybrids. The data cover altitudes between 6000 and 13,500 km, 0600–1800 magnetic local time, and 65°–90° invariant latitude. The distribution and AE dependence agree with low‐altitude perpendicular ion heating and Kp dependence observed by the Freja satellite near 1700 km, suggesting that heated ions become beams or conies at midaltitude. One‐minute AE values provide a higher time resolution for the geomagnetic activity level than Kp and make it possible to investigate the ionospheric outflow during different substorm phases. The highest average UFI number flux is observed during expansion phase when the flux increase from quiet conditions (AE < 100) is a factor of 2, but even during growth and recovery phase the average UFI number flux is 30% higher than for quiet conditions. The UFI frequency of occurrence increases significantly from AE<50 to AE>200, but stays rather constant during growth, expansion, and recovery phase. During substorms (AE>100) a strong increase in the UFI occurrence rate with AE is observed mainly in the cusp region, although a smaller increase is also observed in the postnoon sector.
A neural network study of the mapping from solar magnetic fields to the daily average solar wind velocity
Authors: Wintoft Peter , Lundstedt Henrik
Published: September 2002

Predictions of the daily solar wind velocity (V) at 1 AU from the flux tube expansion factor ƒs are examined with radial basis function neural networks. The flux tube expansion factor is calculated from the potential field model, using Wilcox Solar Observatory magnetograms, with the source surface placed at 2.5 solar radii. The time series extend over 20 years from 1976 to 1995 and consist of approximately 3000 daily values of ƒs and V. The correlation between monthly averages of 1/ƒs and V is 0.57, independent of the assumed Sun‐Earth solar wind travel time τ. However, for daily averages the correlation drops to 0.38 with τ = 5 days. Even adjusting τ to match the observed velocity does not improve on the overall correlation. A time series of ƒs(t) extending over t − 4 to t is used as input to the neural network. The network is trained to predict the solar wind velocity V(t + 2) 2 days ahead. The overall correlation on a test set, not included in the training, is 0.53, and the root‐mean‐square error is 85 km/s. Although the increase is significant, the correlation is still low. However, by studying a number of test cases it is seen that high‐speed streams originating from coronal holes are well predicted, while transient structures related to coronal mass ejections are not predicted. To go further, a more detailed description of the solar magnetic fields must be included. The potential field model does not describe the currents in the corona, and changes of the photospheric magnetic field from day to day are smoothed out. By examining the relative error of the calculated photospheric magnetic field and the observed field, it is shown that the correlation between 1/ƒs(t) and V(t + 5) increases to 0.47 for errors smaller than 20% and drops to 0.3 for errors larger than 34%.
Measuring the seismic properties of Tibetan bright spots: Evidence for free aqueous fluids in the Tibetan middle crust
Authors: Makovsky Yizhaq , Klemperer Simon L.
Published: September 2002

Seismic bright spots are commonly interpreted to mark fluid concentrations, but their nature (melt or aqueous) is usually inferred only from circumstantial evidence of the geologic setting. A band of bright spot reflections has been imaged by Project INDEPTH (International Deep Profiling of Tibet and the Himalayas) at about 15 km depth along 150 km of the northern Yadong‐Gulu rift, southern Tibet. We use INDEPTH three‐component wide‐angle seismic data to measure seismic velocities at the bright spot reflector, and theoretical rock physics bounds to constrain the nature of the fluids. Merging of data from multiple bright spots allows us to use a one‐dimensional approximation. Travel time modeling yields average P and S velocities for the upper crust above the bright spots of 5.3±0.2 and 3.2±0.2 km s−1, respectively. Reflection‐amplitude variation with offset (AVO) modeling constrains the P and S velocities of the bright spots to 3.0±0.8 and 1.6±0.8 km s−1, respectively. Multiple modeling procedures suggest these velocities are not model dependent. Our results imply that of the order of 10% volume of free aqueous fluids in the Tibetan middle crust produces the observed bright spot reflections. The presence of relatively large quantities of free aqueous fluids, presumably mostly saline supercritical H2O, does not preclude the presence of melt but does constrain the maximum temperature at the bright spots to the wet granite solidus (about 650°C) and thus the maximum surface heat flow to ≤110 mW m−2. The observed bright spots can alternatively be explained as a result of transient flow of aqueous fluids through a lower temperature and lower heat flow southern Tibetan crust.
Shallow water tides in the northwest European shelf region from TOPEX/POSEIDON altimetry
Authors: Andersen Ole Baltazar
Published: September 2002

During recent years the accurate measurements from the TOPEX/POSEIDON satellite have improved global ocean tide models considerably. However, these global ocean tide models are still not accurate enough on the continental shelves for detailed oceanographic studies. The need for increasing accuracy in shelf regions calls for inclusion of more than just semidiurnal and diurnal constituents in future global ocean tide models. This is because a considerable part of the tidal variability on the shelves is caused by shallow water constituents. One example is the M4 constituent, which exceeds 50 cm at several locations on the northwest European shelf. So far, TOPEX/POSEIDON has not been considered for resolving these constituents, mainly owing to its coarse ground track resolution. Reliable empirical estimates of several major shallow water constituents can be obtained from TOPEX/POSEIDON by combining along‐track and crossover observations. Estimates of the major shallow water constituents for the northwest European shelf, M4, M6, and MS4, are presented in this study and compared with tide gauges and existing hydrodynamic models.
Space‐time patterns of trends in stratospheric constituents derived from UARS measurements
Authors: Randel William J. , Wu Fei , Russell James M. , Waters Joe
Published: September 2002

The spatial and temporal behavior of low‐frequency changes (trends) in stratospheric constituents measured by instruments on the Upper Atmosphere Research Satellite (UARS) during 1991–98 is investigated. The data include CH4, H2O, HF, HCl, O3, and NO2 from the Halogen Occultation Experiment (HALOE), and O3, ClO, and HNO3 from the Microwave Limb Sounder (MLS). Time series of global anomalies are analyzed by linear regression and empirical orthogonal function analysis. Each of the constituents show significant linear trends over at least some region of the stratosphere, and the spatial patterns exhibit coupling between the different species. Several of the constituents (namely CH4, H2O, HF, HCl, O3, and NO2) exhibit a temporal change in trend rates, with strong changes prior to 1996 and weaker (or reversed) trends thereafter. Positive trends are observed in upper stratospheric ClO, with a percentage rate during 1993–97 consistent with stratospheric HCl increases and with tropospheric chlorine emission rates. Significant negative trends in ozone in the tropical middle stratosphere are found in both HALOE and MLS data during 1993–97, together with positive trends in the tropics near 25 km. These trends are very different from the decadal‐scale ozone trends observed since 1979, and this demonstrates the variability of trends calculated over short time periods. Positive trends in NO2 are found in the tropical middle stratosphere, and spatial coincidence to the observed ozone decreases suggests the ozone is responding to the NO2 increase. Significant negative trends in HNO3 are found in the lower stratosphere of both hemispheres. These coupled signatures offer a fingerprint of chemical evolution in the stratosphere for the UARS time frame.
Isolating nitrated and aromatic aerosols and nitrated aromatic gases as sources of ultraviolet light absorption
Authors: Jacobson Mark Z.
Published: September 2002

Measurements in 1973 and 1987 showed that downward ultraviolet (UV) irradiances within the boundary layer in Los Angeles were up to 50% less than those above the boundary layer. Downward total solar irradiances were reduced by less than 14% in both studies. It is estimated that standard gas and particulate absorbers and scatterers accounted for only about 52–62% of the observed UV reductions at Claremont and Riverside. It is hypothesized that absorption by nitrated and aromatic aerosol components and nitrated aromatic gases caused at least 25–30% of the reductions (with aerosols accounting for about 4/5 of this percent). The remaining reductions are still unaccounted for. Absorbing aerosol components include nitrated aromatics, benzaldehydes, benzoic acids, aromatic polycarboxylic acids, phenols, polycyclic aromatic hydrocarbons, and nitrated inorganics. Many of these species have been observed to date in atmospheric particles, and absorption coefficient data indicate many are strong absorbers at long UV wavelengths. Since aerosols containing nitrated or aromatic aerosols have been observed widely in many areas aside from Los Angeles the finding may account for a portion of UV extinction in those regions as well. In Los Angeles, the finding may be important for predicting smog evolution, since UV reductions associated with high aerosol loadings were estimated to cause a 5–8% decrease in ozone mixing ratios in August 1987. Further laboratory and field studies are needed to quantify better the extent of UV absorption due to nitrated and aromatic aerosols and nitrated aromatic gases.
Diurnal variations in the middle atmosphere observed by UARS
Authors: Sassi Fabrizio , Salby Murry
Published: September 2002

This paper investigates diurnal variations in the dynamical and chemical structure of the middle atmosphere observed by UARS. Dynamical variations are of tidal nature and appear prominently in the temperature field near the equator. The temperature field is smooth enough for higher harmonics of the diurnal cycle, which are unresolved by the UARS sampling, to be negligible. Diurnal variations in the temperature field can therefore be mapped synoptically. Daily maps of the diurnal variation of temperature exhibit meridional and vertical structure typical of the propagating solar diurnal tide. Through advective and photochemical effects, diurnal variations of temperature introduce diurnal variations of ozone in the middle and upper stratosphere, chemical variations which are mapped in similar fashion. Diurnal variations of other chemical species contain higher harmonics, which are undersampled by UARS, preventing diurnal variations in those species from being mapped reliably. Instead, the average diurnal variation over a month or longer is composited from observations at individual local times. In the middle stratosphere, diurnal variations of NOx are strongly influenced by the zonal mean distribution of NOx, which in turn is controlled by the mean meridional circulation. So too are diurnal variations of ClOx but with sign opposite to those of NOx, owing to the coupling of those families.
On the accuracy of in situ water vapor measurements in the troposphere and lower stratosphere with the Harvard Lyman‐α hygrometer
Authors: Hintsa Eric J. , Weinstock Elliot M. , Anderson James G. , May Randy D. , Hurst Dale F.
Published: September 2002

In an effort to better constrain atmospheric water vapor mixing ratios and to understand the discrepancies between different measurements of water vapor in the stratosphere and troposphere, we have carefully examined data from the Harvard Lyman‐α photofragment fluorescence hygrometer, which has flown on the NASA ER‐2 aircraft from 1992 through 1998. The instrument is calibrated in the laboratory before and after each deployment, and the calibration is checked by direct absorption measurements in the troposphere. On certain flights, the ER‐2 flew level tracks during which water vapor varied by up to 80 ppmv, under nearly constant atmospheric conditions; These flights provide a stringent test of our calibration via direct absorption and indicate agreement to within 3%. During the 1997 Photochemistry of Ozone Loss in the Arctic Region In Summer (POLARIS) mission, our Lyman‐α instrument was compared with a new diode laser hygrometer from the Jet Propulsion Laboratory. Overall agreement was 5% during the June/July deployment and 1% for potential temperatures of 490 to 540 K. The accuracy of our instrument is shown to be ±5%, with an additional offset of at most 0.1 ppmv. Data from this instrument, combined with simultaneous measurements of CH4 and H2, are therefore ideal for studies of the hydrogen budget of the lower stratosphere.
A radiosity model for heterogeneous canopies in remote sensing
Authors: García‐Haro F. J. , Gilabert M. A. , Meliá J.
Published: September 2002

A radiosity model has been developed to compute bidirectional reflectance from a heterogeneous canopy approximated by an arbitrary configuration of plants or clumps of vegetation, placed on the ground surface in a prescribed manner. Plants are treated as porous cylinders formed by aggregations of layers of leaves. This model explicitly computes solar radiation leaving each individual surface, taking into account multiple scattering processes between leaves and soil, and occlusion of neighboring plants. Canopy structural parameters adopted in this study have served to simplify the computation of the geometric factors of the radiosity equation, and thus this model has enabled us to simulate multispectral images of vegetation scenes. Simulated images have shown to be valuable approximations of satellite data, and then a sensitivity analysis to the dominant parameters of discontinuous canopies (plant density, leaf area index (LAI), leaf angle distribution (LAD), plant dimensions, soil optical properties, etc.) and scene (sun/ view angles and atmospheric conditions) has been undertaken. The radiosity model has let us gain a deep insight into the radiative regime inside the canopy, showing it to be governed by occlusion of incoming irradiance, multiple scattering of radiation between canopy elements and interception of upward radiance by leaves. Results have indicated that unlike leaf distribution, other structural parameters such as LAI, LAD, and plant dimensions have a strong influence on canopy reflectance. In addition, concepts have been developed that are useful to understand the reflectance behavior of the canopy, such as an effective LAI related to leaf inclination.
Terrigenous Flux in the Rio Grande Rise Area during the Past 1500 ka: Evidence of Deepwater Advection or Rapid Response to Continental Rainfall Patterns?
Authors: Gingele Franz X. , Schmieder Frank , von Dobeneck Tilo , Petschick Rainer , Rühlemann Carsten
Published: September 2002

Surface sediment samples and three gravity cores from the eastern terrace of the Vema Channel, the western flank of the Rio Grande Rise, and the Brazilian continental slope were investigated for physical properties, grain size, and clay mineral composition. Discharge of the Rio Doce is responsible for kaolinite enrichments on the slope south of 20° and at intermediate depths of the Rio Grande Rise. The long‐distance advection of kaolinite with North Atlantic Deep Water from lower latitudes is of minor importance as evidenced by low kaolinite/chlorite ratios on the Mid‐Atlantic Ridge. Cyclic variations of kaolinite/chlorite ratios in all our cores, with maxima in interglacials, are attributed to low‐ and high‐latitude forcing of paleoclimate on the Brazilian mainland and the related discharge of the Rio Doce. A long‐term trend toward more arid and “glacial” conditions from 1500 ka to present is superimposed on the glacial‐interglacial cyclicity.
Turbulence variance characteristics of temperature and humidity in the unstable atmospheric surface layer above a variable pine forest
Authors: Asanuma Jun , Brutsaert Wilfried
Published: September 2002

Second‐order turbulence moments of vertical velocity w, temperature θ, and specific humidity q observed with an aircraft in the atmospheric surface layer over a flat maritime pine forest were used to investigate the applicability of the variance methods to variable terrain. The variances of w and θ were found approximately to obey Monin‐Obukhov similarity, while that of q clearly did not. Further investigation suggested the possibility that the surface variability affected the fluctuations of q and that it also caused a breakdown of the similarity between the scalars θ and q. Different versions of the variance method were tested, and several of them were found to predict the surface flux of sensible heat with satisfactory accuracy. The latent heat flux estimates were in reasonable agreement when the dimensionless functions were calibrated locally.
Optimal remediation of unconfined aquifers: Numerical applications and derivative calculations
Authors: Mansfield Christopher M. , Shoemaker Christine A.
Published: September 2002

This paper extends earlier work on derivative‐based optimization for cost‐effective remediation to unconfined aquifers, which have more complex, nonlinear flow dynamics than confined aquifers. Most previous derivative‐based optimization of contaminant removal has been limited to consideration of confined aquifers; however, contamination is more common in unconfined aquifers. Exact derivative equations are presented, and two computationally efficient approximations, the quasi‐confined (QC) and head independent from previous (HIP) unconfined‐aquifer finite element equation derivative approximations, are presented and demonstrated to be highly accurate. The derivative approximations can be used with any nonlinear optimization method requiring derivatives for computation of either time‐invariant or time‐varying pumping rates. The QC and HIP approximations are combined with the nonlinear optimal control algorithm SALQR into the unconfined‐aquifer algorithm, which is shown to compute solutions for unconfined aquifers in CPU times that were not significantly longer than those required by the confined‐aquifer optimization model. Two of the three example unconfined‐aquifer cases considered obtained pumping policies with substantially lower objective function values with the unconfined model than were obtained with the confined‐aquifer optimization, even though the mean differences in hydraulic heads predicted by the unconfined‐ and confined‐aquifer models were small (less than 0.1%). We suggest a possible geophysical index based on differences in drawdown predictions between unconfined‐ and confined‐aquifer models to estimate which aquifers require unconfined‐aquifer optimization and which can be adequately approximated by the simpler confined‐aquifer analysis.
Modeling removal of bacteriophages MS2 and PRD1 by dune recharge at Castricum, Netherlands
Authors: Schijven Jack F. , Hoogenboezem Wim , Hassanizadeh Majid , Peters Jos H.
Published: September 2002

Removal of model viruses by dune recharge was studied at a field site in the dune area of Castricum, Netherlands. Recharge water was dosed with bacteriophages MS2 and PRD1 for 11 days at a constant concentration in a 10‐ by 15‐m compartment that was isolated in a recharge basin. Breakthrough was monitored for 120 days at six wells with their screens along a flow line. Concentrations of both phages were reduced about 3 log10 within the first 2.4 m and another 5 log10 in a linear fashion within the following 27 m. A model accounting for one‐site kinetic attachment as well as first‐order inactivation was employed to simulate the bacteriophage breakthrough curves. The major removal process was found to be attachment of the bacteriophages. Detachment was very slow. After passage of the pulse of dosed bacteriophages, there was a long tail whose slope corresponds to the inactivation rate coefficient of 0.07–0.09 day−1 for attached bacteriophages. The end of the rising and the start of the declining limbs of the breakthrough curves could not be simulated completely, probably because of an as yet unknown process.
An ecologic explanation for the Permo‐Triassic carbon and sulfur isotope shifts
Authors: Broecker Wallace S. , Peacock Synte
Published: September 2002

The boundary between Late Permian and Early Triassic stratigraphic sequences is characterized by the onset of a marked shift in the isotopic composition of both marine carbonates and sulfates. The abrupt 3‰ decrease in the carbon isotope ratio of carbonates and the more gradual 5‰ increase in the sulfur isotope ratio of sulfates can be explained by changes in the nature of the Earth's ecosystems induced by the massive Permo‐Triassic extinctions. We propose that the continental ecosystem responsible for the preservation and burial of organic matter during Permian time was disrupted and that the relatively efficient marine food web of Permian time was replaced by a less efficient system, which allowed for a greater fraction of the marine organic matter to reach the seafloor. These changes were reflected by a major shift in the depositional environment for the reduced component of material accumulating in sediments. During the Permian, organic carbon burial on the continents dominated, whereas during the Triassic, deposition of organic carbon on the seafloor dominated, allowing sulfides to become an important component of the reduced phase.
The trend in atmospheric methane δ13C and implications for isotopic constraints on the global methane budget
Authors: Lassey Keith R. , Lowe David C. , Manning Martin R.
Published: September 2002

A recent paper by Tans [1997] has drawn attention to the isotopic disequilibrium that inevitably prevails when atmospheric methane is not in steady state with its sources, noting in particular the very slow adjustment of the isotopic signature δ13C toward its steady state. Our aim in this paper is to clarify the nature of disequilibrium effects on δ13C(CH4) and to assess their likely magnitudes in the global atmosphere over recent decades. We use a simple model simulation incorporating a plausible scenario of the global methane source history over 1700–2010, which includes an unchanged source since 1990. The simulation of both mixing ratio and δ13C compare favorably with the secular features of a 10‐year data set (1988–1998) from Baring Head, New Zealand, and of a 17‐year data set (1978–1995) in air archived from Cape Grim, Australia. This corroborates a recent analysis of those data sets and their compatibility with stabilized sources. We show that the slow adjustment of δ13C toward steady state arises from the effect of isotope fractionation on the cancellation of contributing terms to δ13C. We explore the implications of disequilibrium for the usual practice of relating δ13C values in the atmosphere to those in the aggregate source through a shift induced by fractionation and quantify the flaws in this practice. Finally, we examine the sensitivity of the atmospheric secular response, in both mixing ratio and δ13C, to sustained changes in source and sink and show that δ13C is a potentially powerful diagnostic of such changes.