bluuebunny/crossref_metadata_2025 huggingface dataset:
Three‐dimensional sonographic description of the fetal frontal bones and metopic suture
Authors: Faro C. , Benoit B. , Wegrzyn P. , Chaoui R. , Nicolaides K. H.
Published: September 2005

Objective

To describe the morphology of the frontal bones and metopic suture at 9–34 weeks of gestation using three‐dimensional (3D) ultrasonography.

Methods

This was a cross‐sectional study of the frontal bones and metopic suture in 16 fetuses at 9–34 weeks of gestation. 3D ultrasonography was used to obtain volumes of the whole fetal skull in the mid‐sagittal plane. The volumes were analyzed using the rendering mode and transparent maximum mode in order to achieve a clear view of the frontal bones and the metopic suture.

Results

At 9 weeks, a small ossification center was visible in the middle of each supraorbital part of the frontal bones and by 11 weeks the frontal bones appeared as ‘thick eyebrows’. In the second trimester there was progressive radial bone expansion and delineation of the metopic suture and in the third trimester there was closure of the metopic suture, starting from the glabella and moving upwards towards the anterior fontanelle.

Conclusions

This study provides 3D ultrasound images that illustrate the process of ossification of the frontal bones and the subsequent development of the metopic suture during prenatal life. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
Population ecology of polar bears at Svalbard, Norway
Authors: Derocher Andrew E.
Published: September 2005

The population ecology of polar bears at Svalbard, Norway, was examined from 1988 to 2002 using live‐captured animals. The mean age of both females and males increased over the study, litter production rate and natality declined and body length of adults decreased. Dynamics of body mass were suggestive of cyclical changes over time and variation in body mass of both adult females and adult males was related to the Arctic Oscillation index. Similarly, litter production rate and natality correlated with the Arctic Oscillation index. The changes in age‐structure, reproductive rates and body length suggest that recovery from over‐harvest continued for almost 30 years after harvest ended in 1973 and that density‐dependent changes are perhaps being expressed in the population. However, the variation in reproduction and body mass in the population show a relationship between large‐scale climatic variation and the upper trophic level in an Arctic marine ecosystem. Similar change in other polar bear populations has been attributed to climate change, and further research is needed to establish linkages between climate and the population ecology of polar bears.
Selective activation of adrenergic β1 receptors induces heme oxygenase 1 production in RAW264.7 cells
Authors: Sun Jinji , Kim Sung Jae , Park Min Kyu , Kim Hye Jung , Tsoy Irina , Kang Young Jin , Lee Young Soo , Seo Han Geuk , Lee Jae Heun , Chang Ki Churl
Published: September 2005

We hypothesized that catecholamines through β‐adrenoceptor might modulate macrophage function. We showed that isoproterenol concentration‐dependently induced HO‐1 production through β1‐but not β2‐adrenoceptor. Production was increased by forskolin and inhibited by pretreatment with the PKA inhibitor, H‐89. Furthermore, induction of HO‐1 by isoproterenol effectively protected RAW264.7 cells from effects of glucose oxidase treatment, which was abrogated either by HO‐1 inhibitor, ZnPP IX and β‐adenoceptor antagonist, propranolol. Thus, stimulation of HO‐1 production through β1‐adenoceptors, and via the PKA pathways by isoproterenol, can enable RAW264.7 cells to resist oxidant stress, suggesting that catecholamine hormones may be necessary, at least, to maximize defending role of macrophages.
Comparative simulations of aquaporin family: AQP1, AQPZ, AQP0 and GlpF
Authors: Hashido Masanori , Ikeguchi Mitsunori , Kidera Akinori
Published: September 2005

Molecular dynamics simulations were performed for four members of the aquaporin family (AQP1, AQPZ, AQP0, and GlpF) in the explicit membrane environment. The single‐channel water permeability, p
f, was evaluated to be GlpF ∼ AQPZ >
AQP1 ≫ AQP0, while their relative pore sizes were GlpF ≫ AQP1 >
AQPZ ≫ AQP0. This relation between p
f and pore size indicates that water permeability was determined not only by the channel radius, but also another competing factor. Analysis of water dynamics revealed that this factor was the single‐file nature of water transport.
Caspase activation is involved in chronic periodontitis
Authors: Bantel Heike , Beikler Thomas , Flemmig Thomas F. , Schulze-Osthoff Klaus
Published: September 2005

Periodontitis, a common infectious disease, is initiated by various gram‐negative bacteria and characterized by the destruction of the periodontal tissue. Here, we investigated the role of caspases, intracellular proteases that are the key mediators of apoptosis. We show that activation of caspase‐3 and caspase‐7 is considerably enhanced in gingival tissue from patients with periodontitis. We also demonstrate in in vitro experiments that various periodontopathic bacteria exert a direct growth‐suppressing effect and, moreover, can trigger a host‐mediated cytotoxic activity involving the CD95 death receptor. Our data suggest that caspase activation is a prominent feature in periodontitis‐associated tissue injury.
The origin of the high sensitivity of muscle fructose 1,6‐bisphosphatase towards AMP
Authors: Rakus D. , Maciaszczyk E. , Wawrzycka D. , Ułaszewski S. , Eschrich K. , Dzugaj A.
Published: September 2005

Adenosine 5′‐monophosphate (AMP) inhibits muscle fructose 1,6‐bisphosphatase (FBPase) about 44 times stronger than the liver isozyme. The key role in strong AMP binding to muscle isozyme play K20, T177 and Q179. Muscle FBPase which has been mutated towards the liver enzyme (K20E/T177M/Q179C) is inhibited by AMP about 26 times weaker than the wild‐type muscle enzyme, but it binds the fluorescent AMP analogue, 2′,3′‐O‐(2,4,6‐trinitrophenyl)adenosine 5′‐monophosphate (TNP‐AMP), similarly to the wild‐type liver enzyme. The reverse mutation of liver FBPase towards the muscle isozyme significantly increases the affinity of the mutant to TNP‐AMP. High affinity to the inhibitor but low sensitivity to AMP of the liver triple mutant suggest differences between the isozymes in the mechanism of allosteric signal transmission.
The dimeric form of flavocytochrome P450 BM3 is catalytically functional as a fatty acid hydroxylase
Authors: Neeli Rajasekhar , Girvan Hazel M. , Lawrence Andrew , Warren Martin J. , Leys David , Scrutton Nigel S. , Munro Andrew W.
Published: September 2005

In the model P450 BM3 system, the P450 is fused to its diflavin reductase partner in a single polypeptide. BM3 dimerizes in solution, but the catalytic relevance of the phenomenon was hitherto unknown. We show that BM3 fatty acid hydroxylase specific activity decreases sharply at low enzyme concentrations, consistent with separation of active dimer into inactive monomer. Reductase‐dependent specific activities are maintained or enhanced at low concentration, suggesting inter‐flavin electron transfer is unaffected. Fatty acid oxidation is reconstituted by mixing inactive oxygenase (A264H) and FMN‐depleted (G570D) mutants, demonstrating that inter‐monomer (FMN1‐to‐heme2) electron transfer supports oxygenase activity in the BM3 dimer.
Evidence for proprotein convertase activity in the endoplasmic reticulum/early Golgi
Authors: Salvas Alexandre , Benjannet Suzanne , Reudelhuber Timothy L. , Chrétien Michel , Seidah Nabil G.
Published: September 2005

Processing of precursor proteins by the proprotein convertases is thought to occur mainly in the trans‐Golgi network or post‐Golgi compartments. Such cleavage is inhibited by the prosegment of the convertases. During our studies of the use of the inhibitory prosegment of PC1, we noticed that a construct containing the prosegment fused to the C‐terminal secretory granule sorting domain was cleaved in the endoplasmic reticulum (ER) at a pair of basic residues, best recognized by furin and PC7. This was further confirmed when this construct was fused at the C‐terminus with a KDEL ER‐retention signal. This suggests that the convertases could cleave some substrates within the ER, possibly by displacing the inhibitory prosegment associated with them.
Identification of a novel bean α‐amylase inhibitor with chitinolytic activity
Authors: Dayler Charles S.A. , Mendes Paulo A.M. , Prates Maura V. , Bloch Carlos , Franco Octavio L. , Grossi-de-Sá Maria F.
Published: September 2005

Zabrotes subfasciatus is a devastating starch‐dependent storage bean pest. In this study, we attempted to identify novel α‐amylase inhibitors from wild bean seeds, with efficiency toward pest α‐amylases. An inhibitor named Phaseolus vulgaris chitinolytic α‐amylase inhibitor (PvCAI) was purified and mass spectrometry analyses showed a protein with 33 330 Da with the ability to form dimers. Purified PvCAI showed significant inhibitory activity against larval Z. subfasciatus α‐amylases with no activity against mammalian enzymes. N‐terminal sequence analyses showed an unexpected high identity to plant chitinases from the glycoside hydrolase family 18. Furthermore, their chitinolytic activity was also detected. Our data provides compelling evidence that PvCAI also possessed chitinolytic activity, indicating the emergence of a novel α‐amylase inhibitor class.
Single chain antibody against the common epitope of mutant p53 restores wild‐type activity to mutant p53 protein
Authors: Orgad Sara , Goldfinger Naomi , Cohen Gerald , Rotter Varda , Solomon Beka
Published: September 2005

Here, we describe the biological activity of ME1, a mouse single chain Fv fragment (scFv) against the common epitope of mutant p53, which is efficiently expressed in mammalian cells. We found that in vivo interaction of the conformational p53 mutant R175H protein with the scFv resulted in the acquisition of wild‐type p53 characteristics, manifested in trans‐activation of p21, as well as induction of apoptosis. Moreover, antibody binding leads to abrogation of the mutant p53 mediated “gain of function” as estimated by downregulation of EGR‐1, a transcriptional target of mutant p53. These findings suggest that the scFv restores wild‐type properties to mutant p53.
Racism, psychosis and common mental disorder among ethnic minority groups in England
Authors: KARLSEN SAFFRON , NAZROO JAMES Y. , McKENZIE KWAME , BHUI KAMALDEEP , WEICH SCOTT
Published: September 2005

Background. The aim of this study was to explore the relationship between risk of psychosis, common mental disorder (CMD) and indicators of racism among ethnic minority groups in England and how this relationship may vary by particular ethnic groups.

Method. A multivariate analysis was carried out of quantitative, cross-sectional data from a nationally representative community sample of people aged between 16 and 74 years from the largest ethnic minority groups in England: those of Caribbean, Indian, Pakistani, Bangladeshi and Irish origin.

Results. Experience of interpersonal racism and perceiving racism in the wider society each have independent effects on the risk of CMD and psychosis, after controlling for the effects of gender, age and socio-economic status. There was some variation in the findings when they were conducted for separate ethnic and gender groups.

Conclusions. An understanding of the relationship between racism and mental health may go some way towards explaining the ethnic variations found in both CMD and, particularly, psychosis.
Does provider adherence to a treatment guideline change clinical outcomes for patients with bipolar disorder? Results from the Texas Medication Algorithm Project
Authors: DENNEHY ELLEN B. , SUPPES TRISHA , RUSH A. JOHN , MILLER ALEXANDER L. , TRIVEDI MADHUKAR H. , CRISMON M. LYNN , CARMODY THOMAS J. , KASHNER T. MICHAEL
Published: September 2005

Background. Despite increasing adoption of clinical practice guidelines in psychiatry, there is little measurement of provider implementation of these recommendations, and the resulting impact on clinical outcomes. The current study describes one effort to measure these relationships in a cohort of public sector out-patients with bipolar disorder.

Method. Participants were enrolled in the algorithm intervention of the Texas Medication Algorithm Project (TMAP). Study methods and the adherence scoring algorithm have been described elsewhere. The current paper addresses the relationships between patient characteristics, provider experience with the algorithm, provider adherence, and clinical outcomes. Measurement of provider adherence includes evaluation of visit frequency, medication choice and dosing, and response to patient symptoms. An exploratory composite ‘adherence by visit’ score was developed for these analyses.

Results. A total of 1948 visits from 141 subjects were evaluated, and utilized a two-stage declining effects model. Providers with more experience using the algorithm tended to adhere less to treatment recommendations. Few patient factors significantly impacted provider adherence. Increased adherence to algorithm recommendations was associated with larger decreases in overall psychiatric symptoms and depressive symptoms over time, but did not impact either immediate or long-term reductions in manic symptoms.

Conclusions. Greater provider adherence to treatment guideline recommendations was associated with greater reductions in depressive symptoms and overall psychiatric symptoms over time. Additional research is needed to refine measurement and to further clarify these relationships.
Problem-solving ability and repetition of deliberate self-harm: a multicentre study
Authors: McAULIFFE CARMEL , CORCORAN PAUL , KEELEY HELEN S. , ARENSMAN ELLA , BILLE-BRAHE UNNI , De LEO DIEGO , FEKETE SANDOR , HAWTON KEITH , HJELMELAND HEIDI , KELLEHER MARGARET , KERKHOF AD J.F.M. , LÖNNQVIST JOUKO , MICHEL KONRAD , SALANDER-RENBERG ELLINOR , SCHMIDTKE ARMIN , VAN HEERINGEN KEES , WASSERMAN DANUTA
Published: September 2005

Background. While recent studies have found problem-solving impairments in individuals who engage in deliberate self-harm (DSH), few studies have examined repeaters and non-repeaters separately. The aim of the present study was to investigate whether specific types of problem-solving are associated with repeated DSH.

Method. As part of the WHO/EURO Multicentre Study on Suicidal Behaviour, 836 medically treated DSH patients (59% repeaters) from 12 European regions were interviewed using the European Parasuicide Study Interview Schedule (EPSIS II) approximately 1 year after their index episode. The Utrecht Coping List (UCL) assessed habitual responses to problems.

Results. Factor analysis identified five dimensions – Active Handling, Passive-Avoidance, Problem Sharing, Palliative Reactions and Negative Expression. Passive-Avoidance – characterized by a pre-occupation with problems, feeling unable to do anything, worrying about the past and taking a gloomy view of the situation, a greater likelihood of giving in so as to avoid difficult situations, the tendency to resign oneself to the situation, and to try to avoid problems – was the problem-solving dimension most strongly associated with repetition, although this association was attenuated by self-esteem.

Conclusions. The outcomes of the study indicate that treatments for DSH patients with repeated episodes should include problem-solving interventions. The observed passivity and avoidance of problems (coupled with low self-esteem) associated with repetition suggests that intensive therapeutic input and follow-up are required for those with repeated DSH.
Adolescent alcohol use is a risk factor for adult alcohol and drug dependence: evidence from a twin design
Authors: GRANT JULIA D. , SCHERRER JEFFREY F. , LYNSKEY MICHAEL T. , LYONS MICHAEL J. , EISEN SETH A. , TSUANG MING T. , TRUE WILLIAM R. , BUCHOLZ KATHLEEN K.
Published: September 2005

Background. Early alcohol use is associated with abuse and dependence of licit and illicit substances later in life. The role of genetic and environmental factors in this association is not conclusive.

Method. In 1992, data on substance use, abuse/dependence and psychiatric disorders were collected from 8169 male twin members of the Vietnam Era Twin Registry. The interview obtained age of onset of regular drinking (one drink/month for 6 or more months). Regression analyses of twin pairs discordant for early alcohol use tested whether the association between early drinking (before age 17) and adult substance use and abuse/dependence remained after controlling for genetic factors, family environment and covariates. Twin models tested for common genetic and/or environmental influences on early drinking and adult alcohol dependence and ever use and abuse/dependence on marijuana and other drugs.

Results. Co-twin analyses suggested the association between early regular alcohol use and adult alcohol dependence, marijuana and other drug use, and marijuana and other drug abuse/dependence could not be entirely explained by common genetic and shared family environmental factors. Genetic contributions to early regular drinking were significantly correlated with those on use of marijuana (rA=0·59), use of other drugs (rA=0·64), alcohol dependence (rA=0·54) and abuse/dependence of marijuana and other drugs (rA=0·63 and 0·66). Small but significant unique environmental correlations (rE range 0·11–0·22) indicated that familial factors could not entirely explain the association between early alcohol use and later substance use, abuse and dependence.

Conclusions. Early regular drinking is associated with later alcohol dependence and use, abuse/dependence on drugs. The association is not entirely explained by genetic or shared family environmental factors. This suggests unique environmental factors contribute to transitions from early regular alcohol drinking to use, abuse and dependence on alcohol and other substances.
Low‐frequency variability of the large‐scale ocean circulation: A dynamical systems approach
Authors: Dijkstra Henk A. , Ghil Michael
Published: September 2005

Oceanic variability on interannual, interdecadal, and longer timescales plays a key role in climate variability and climate change. Paleoclimatic records suggest major changes in the location and rate of deepwater formation in the Atlantic and Southern oceans on timescales from millennia to millions of years. Instrumental records of increasing duration and spatial coverage document substantial variability in the path and intensity of ocean surface currents on timescales of months to decades. We review recent theoretical and numerical results that help explain the physical processes governing the large‐scale ocean circulation and its intrinsic variability. To do so, we apply systematically the methods of dynamical systems theory. The dynamical systems approach is proving successful for more and more detailed and realistic models, up to and including oceanic and coupled ocean‐atmosphere general circulation models. In this approach one follows the road from simple, highly symmetric model solutions, through a “bifurcation tree,” toward the observed, complex behavior of the system under investigation. The observed variability can be shown to have its roots in simple transitions from a circulation with high symmetry in space and regularity in time to circulations with successively lower symmetry in space and less regularity in time. This road of successive bifurcations leads through multiple equilibria to oscillatory and eventually chaotic solutions. Key features of this approach are illustrated in detail for simplified models of two basic problems of the ocean circulation. First, a barotropic model is used to capture major features of the wind‐driven ocean circulation and of the changes in its behavior as wind stress increases. Second, a zonally averaged model is used to show how the thermohaline ocean circulation changes as buoyancy fluxes at the surface increase. For the wind‐driven circulation, multiple separation patterns of a “Gulf‐Stream like” eastward jet are obtained. These multiple equilibria are followed by subannual and interannual oscillations of the jet and of the entire basin's circulation. The multiple equilibria of the thermohaline circulation include deepwater formation near the equator, near either pole or both, as well as intermediate possibilities that bear some degree of resemblance to the currently observed Atlantic overturning pattern. Some of these multiple equilibria are subject, in turn, to oscillatory instabilities with timescales of decades, centuries, and millennia. Interdecadal and centennial oscillations are the ones of greatest interest in the current debate on global warming and on the relative roles of natural and anthropogenic variability in it. They involve the physics of the truly three‐dimensional coupling between the wind‐driven and thermohaline circulation. To arrive at this three‐dimensional picture, the bifurcation tree is sketched out for increasingly complex models for both the wind‐driven and the thermohaline circulation.
Relativistic nucleon and electron production in the 2003 October 28 solar event
Authors: Miroshnichenko L. I. , Klein K.‐L. , Trottet G. , Lantos P. , Vashenyuk E. V. , Balabin Y. V. , Gvozdevsky B. B.
Published: September 2005

A flare on 2003 October 28 produced a relativistic particle event at Earth, although the active region AR 10486 was located to the east of the central meridian of the Sun. The paper considers features related to the acceleration at the Sun and the propagation to the Earth of energetic particles in this event, which occurred on a disturbed interplanetary background caused by preceding activity on the Sun and a corotating high‐speed solar wind stream. From a study of the onset times of the event at different neutron monitors, we conclude that the earliest arriving solar particles were neutrons. The first relativistic protons arrived a few minutes later. Among relativistic solar protons (RSP), two populations could clearly be distinguished: prompt and delayed ones. The prompt solar protons caused an impulse‐like increase at a few neutron monitor stations. The delayed solar protons arrived at Earth 0.5 hours later. Both prompt and delayed relativistic protons arrived at Earth from the antisunward direction. On the other hand, subrelativistic electrons that were traced by their radio emission from meter waves (Nançay Radioheliograph and Decametric Array) to kilometer waves (Wind/WAVES) are accompanied by metric radio emission in the western solar hemisphere, far from the flaring active region. We propose a scenario that reconciles the unusual features of energetic particles at the Earth with the observed structure of the interplanetary magnetic field, which suggests the Earth is at the interface between an interplanetary coronal mass ejection (ICME) and a corotating stream during the event. In this scenario the high‐energy protons and electrons are accelerated in the flaring active region, injected into the eastern leg of an ICME loop rooted in the active region, and reach the Earth from the antisunward direction after passing through the summit of the loop. We attribute the promptly escaping subrelativistic electrons to acceleration in the western solar hemisphere and propagation along the nominal Parker spiral.
Coronal mass ejection kinematics deduced from white light (Solar Mass Ejection Imager) and radio (Wind/WAVES) observations
Authors: Reiner M. J. , Jackson B. V. , Webb D. F. , Mizuno D. R. , Kaiser M. L. , Bougeret J.‐L.
Published: September 2005

White‐light and radio observations are combined to deduce the coronal and interplanetary kinematics of a fast coronal mass ejection (CME) that was ejected from the Sun at about 1700 UT on 2 November 2003. The CME, which was associated with an X8.3 solar flare from W56°, was observed by the Mauna Loa and Solar and Heliospheric Observatory (SOHO) Large‐Angle Spectrometric Coronograph (LASCO) coronagraphs to 14 R⊙. The measured plane‐of‐sky speed of the LASCO CME was 2600 km s−1. To deduce the kinematics of this CME, we use the plane‐of‐sky white light observations from both the Solar Mass Ejection Imager (SMEI) all‐sky camera on board the Coriolis spacecraft and the SOHO/LASCO coronagraph, as well as the frequency drift rate of the low‐frequency radio data and the results of the radio direction‐finding analysis from the WAVES experiment on the Wind spacecraft. In agreement with the in situ observations for this event, we find that both the white light and radio observations indicate that the CME must have decelerated significantly beginning near the Sun and continuing well into the interplanetary medium. More specifically, by requiring self‐consistency of all the available remote and in situ data, together with a simple, but not unreasonable, assumption about the general characteristic of the CME deceleration, we were able to deduce the radial speed and distance time profiles for this CME as it propagated from the Sun to 1 AU. The technique presented here, which is applicable to mutual SMEI/WAVES CME events, is expected to provide a more complete description and better quantitative understanding of how CMEs propagate through interplanetary space, as well as how the radio emissions, generated by propagating CME/shocks, relate to the shock and CME. This understanding can potentially lead to more accurate predictions for the onset times of space weather events, such as those that were observed during this unique period of intense solar activity.
Interplanetary coronal mass ejection and ambient interplanetary magnetic field correlations during the Sun‐Earth connection events of October–November 2003
Authors: Farrugia C. J. , Matsui H. , Kucharek H. , Torbert R. B. , Smith C. W. , Jordanova V. K. , Ogilvie K. W. , Lepping R. P. , Berdichevsky D. B. , Terasawa T. , Kasper J. , Mukai T. , Saito Y. , Skoug R.
Published: September 2005

Magnetic field observations made during 28 October to 1 November 2003, which included two fast interplanetary coronal mass ejections (ICMEs), allow a study of correlation lengths of magnetic field parameters for two types of interplanetary (IP) structures: ICMEs and ambient solar wind. Further, they permit the extension of such investigations to the magnetosheath and to a distance along the Sun‐Earth line (X) of about 400 RE. Data acquired by three spacecraft are examined: ACE, in orbit around the L1 point; Geotail, traveling eastward in the near‐Earth solar wind (at R ∼ 30 RE); and Wind, nominally in the distant geomagnetic tail (R ∼ −160 RE) but making repeated excursions into the magnetosheath/solar wind due to the flapping of the tail. Analyses are presented in both time and frequency domains. We find significant differences in the cross‐correlation/coherence properties of the ambient interplanetary magnetic field (IMF) and ICME parameters. For the ambient IMF, we find high coherence to be confined to low frequencies, consistent with other studies. In contrast, ICME magnetic field parameters remain generally coherent up to much higher frequencies. Scale lengths of ICME magnetic field parameters are in excess of 400 RE. High speeds of ∼1700 km s−1 are inferred from the plot of phase difference versus frequency, consistent with that obtained from plasma instruments. To strengthen these results and to extend them to include dependence on the distance perpendicular to the Sun‐Earth line (Y), we examine a 28‐day interval in year 2001 characterized by a sequence of 10 ICMEs and containing roughly equal ambient solar wind and ICME time intervals. ACE‐Wind X and Y separations were ∼220 and ∼250 RE, respectively. We find good coherence/correlation alternating with poor values. In particular, we find that in general ICME coherence/correlation lengths along Y are larger by a factor of 3–5 than those quoted in the literature for ambient solar wind parameters. Our findings are good news for the space weather effort, which depends crucially on predicting the arrival of large events, since they make possible the placement of upstream monitors to give a longer lead time than at L1.
Hybrid coupled modeling of the tropical Pacific using neural networks
Authors: Li Shuyong , Hsieh William W. , Wu Aiming
Published: September 2005

To investigate the potential for improving hybrid coupled models (HCM) of the tropical Pacific by the use of neural network (NN) methods for nonlinear regression, NN was introduced for the nonlinear parameterization of the subsurface temperature in the Lamont ocean model and for the nonlinear estimation of the wind stress anomalies (WSA) from the sea surface temperature anomalies (SSTA). For comparison, corresponding linear regression (LR) models were also built. By combining the NN or the LR version of the ocean model and the atmospheric model, four HCMs resulted. For the coupled model Niño3 SSTA spectrum, using NN in the ocean model produced a much broader spectrum than using LR, which gave basically a single narrow spectral peak. Using NN in the atmospheric model in addition to the ocean model further broadened the SSTA spectrum, yielding a spectrum with two main peaks as observed. Principal component analysis (PCA) and nonlinear PCA (NLPCA) were used to analyze the SSTA and WSA. By comparing the NLPCA mode 1 and the PCA mode 1, we found that all the coupled models (including the original Lamont coupled model) were too linear compared to the observations. However, using NN in the ocean model and in the atmospheric model, we were able to alleviate the weak nonlinearity in the coupled models.
Flood dispersal and deposition by near‐bed gravitational sediment flows and oceanographic transport: A numerical modeling study of the Eel River shelf, northern California
Authors: Harris Courtney K. , Traykovski Peter A. , Geyer W. Rockwell
Published: September 2005

A large flood of the Eel River, northern California, created a thick sediment deposit between water depths of 50 and 70 m in January 1997. The freshwater plume, however, confined sediment delivery to water depths shallower than 30 m. Mechanisms proposed to explain the apparent cross‐shelf transport include dispersal by oceanographic currents, resuspension by energetic waves, and gravitationally forced transport of a thin layer of fluidized mud. Field observations indicate that these processes were all active but cannot determine their relative significance or whether these mechanisms alone explain the location, size, and timing of deposition. Approximately 30% of the sediment delivered by the Eel River is accounted for in the midshelf mud bed and inner shelf, but the fate of the remaining 70% is uncertain. A three‐dimensional, hydrodynamic model was used to examine potential mechanisms of sediment transport on the Eel River shelf. The model includes suspended sediment transport and was modified to account for a thin, near‐bed layer of fluidized mud. It was used to simulate flood dispersal on the Eel River shelf, to compare the relative importance of transport within the near‐bed fluid mud layer to suspended sediment transport, and to evaluate sediment budgets for floods. Settling properties of fine‐grained sediment, both within the flood plume and the fluid mud layer, critically impact depositional patterns. To a lesser degree, wind‐driven ocean currents influence the volume of sediment that escapes the shelf, and wave magnitude affects the cross‐shelf location of flood deposits. Though dilute suspension accounts for a large fraction of total flux, cross‐shelf transport by gravitational forcing appears necessary to produce a midshelf mud deposit similar in volume, location, and timing to those seen offshore of the Eel River.
Fog and low clouds in a coastally trapped disturbance
Authors: Thompson William T. , Burk Stephen D. , Lewis John
Published: September 2005

One of the most distinctive features of coastally trapped disturbances (CTDs) is the tongue of fog and low clouds propagating poleward along the west coast of continents against the typical coast‐parallel equatorward flow. In this study, characteristics of the fog and low clouds observed in conjunction with a CTD event on 15–16 June 2000 are investigated. In particular, we examine the relative importance of radiation, cloud microphysical processes, advection, entrainment, and surface fluxes to the fog and cloud layer associated with the CTD. A simulation of the event is produced using the Naval Research Laboratory's nonhydrostatic Coupled Ocean/Atmosphere Mesoscale Prediction System. Propagation of the wind shift and cloud tongue and the extent of fog and low clouds in the model results are compared with coastal buoy data and satellite imagery. A critical value of the Bowen ratio delineates the extent of fog with lower values to the south in the low cloud area. Because the Bowen ratio provides limited information concerning the relative roles of sensible and latent heat fluxes in the cloud layer, we examine the ratio β of integrated buoyancy generation due to liquid water flux to the integrated positive buoyancy flux. The timing difference between arrival of the CTDs' wind shift and the arrival of the fog is found to be central to the evolution of the cloud liquid water field. Several sensitivity studies are also carried out in order to further understand the roles of radiative cooling and surface latent and sensible heat fluxes.
Characterization of stratospheric liquid ternary solution aerosol from broadband infrared extinction measurements
Authors: Sasano Yasuhiro , Oshchepkov Sergey , Yokota Tatsuya , Nakajima Hideaki
Published: September 2005

Characterization of stratospheric liquid ternary solution (LTS) aerosol is studied as an inverse problem in retrieving particle volume size distribution and chemical composition of ternary droplets using the extinction coefficient over wavelengths of 3 to 12 μm. The retrieval method comprises a constrained, weighted least squares minimization procedure between measured and modeled spectra. The constraints restrict the first derivative of the particle size distribution with respect to particle size and restrict the relationship between weight percents of discrete partials (H2SO4/H2O/HNO3) in the ternary droplets using the Carslaw equilibrium model. In the inverse modeling, emphasis is given to minimize the number of reference spectra up to consideration of two mostly binary components composed of H2SO4/H2O and HNO3/H2O solutions. This permits the retrieval of particle volume size distribution independently of particle chemical composition and therefore simply adopts the inversion method for the processing of spaceborne occultation measurements when other aerosol/cloud components along with trace gases are subject to identification. We initially carry out numerical tests by applying the inversion method to synthetic extinction measurements in order to study the limitations of the retrievals over wide ranges of microphysical parameters. A case study in processing actual space‐borne data obtained by the Improved Limb Atmospheric Spectrometer (ILAS) demonstrates the efficiency of the retrievals.
Divergent vegetation growth responses to the 2003 heat wave in the Swiss Alps
Authors: Jolly William M. , Dobbertin Matthias , Zimmermann Niklaus E. , Reichstein Markus
Published: September 2005

In 2003, Europe experienced its hottest summer in >500 years. Satellite‐derived photosynthetic activity estimates across the Alps revealed a pattern of high elevation growth enhancement and low elevation growth suppression in response to these extreme summer temperatures. Surface weather‐derived effective growing season lengths were shorter in 2003 by an average of 9% and 5% for colline and montane areas respectively and were 2%, 12% and 64% longer for subalpine, alpine and nival areas respectively. In situ forest growth measurements of 244 trees at 15 sites across Switzerland verified this pattern and revealed that this divergent response was consistent between species. We suggest that warmer summer temperatures lengthened the snow‐free growing season at high elevations while they increased summertime evaporative demand at lower elevations. Our investigation demonstrates that climatic changes are affecting plants beyond simply shifting the elevation belts upwards.
Tree‐ring reconstruction of Crimean drought and lake chronology correction
Authors: Solomina Olga , Davi Nicole , D'Arrigo Rosanne , Jacoby Gordon
Published: October 2005

The first verifiable reconstruction of spring (April–July) precipitation is presented for Crimea, Ukraine. It is derived from Crimean pine (Pinus hamata) ring‐width data spanning A.D. 1620–2002. The reconstruction accounts for 37% of the variance in observed precipitation over 1896–1988. Most droughts recorded in Crimean historical documents in the 17th–19th centuries coincide with below‐average reconstructed precipitation in the concurrent or following year. An 11‐year filtered version of the reconstruction correlates with an annually‐laminated sediment‐thickness record from Saki Lake (4188 years in length), once this record is shifted backward by 15 years. The offset may be explained by anthropogenic changes at the lake in the late 19th century. The significant relationship between the lake sediments and reconstruction suggests that the lake record is also a moisture indicator. If so, the wettest period of the past 1500 years (∼AD1050–1250) broadly coincides with the “Medieval Warm Period” (MWP) in Crimea.
Understanding future patterns of increased precipitation intensity in climate model simulations
Authors: Meehl Gerald A. , Arblaster Julie M. , Tebaldi Claudia
Published: September 2005

In a future climate warmed by increased greenhouse gases, increases of precipitation intensity do not have a uniform spatial distribution. Here we analyze a multi‐model AOGCM data set to examine processes that produce the geographic pattern of these precipitation intensity changes over land. In the tropics, general increases in water vapor associated with positive SST anomalies in the warmer climate produce increased precipitation intensity over most land areas. In the midlatitudes, the pattern of precipitation intensity increase is related in part to the increased water vapor being carried to areas of mean moisture convergence to produce greater precipitation, as well as to changes in atmospheric circulation. Advective effects, indicated by sea level pressure changes, contribute to greatest precipitation intensity increases (as well as mean precipitation increases) over northwestern and northeastern North America, northern Europe, northern Asia, the east coast of Asia, southeastern Australia, and south‐central South America.
Antarctica cloud cover for October 2003 from GLAS satellite lidar profiling
Authors: Spinhirne J. D. , Palm S. P. , Hart W. D.
Published: September 2005

Bright surfaces and low surface temperature limit the study of Antarctica cloud cover by passive techniques. Starting in 2003 the Geoscience Laser Altimeter System (GLAS) provides the first measurements of polar clouds by satellite lidar. From the GLAS data the presence and height of all clouds are detected, and in the case of transmissive clouds that predominate in the Antarctica, the thickness is also found. Initial results for October 2003 data are summarized. There are two basic cloud types profiled: stratus below 3 km and cirrus form clouds with cloud top altitude and thickness tending at 12 km and 1.3 km. Zonal average cloud fraction varies from over 93 % for ocean and coastal regions to a consistent average of 40% over the East Antarctic plateau and 60–90% over West Antarctica. Differences between the zonal average GLAS and MODIS cloud fractions are as much as 40% over the continent.
Greenland mass balance from GRACE
Authors: Velicogna Isabella , Wahr John
Published: September 2005

We use 22 monthly GRACE (Gravity Recovery and Climate Experiment) gravity fields to estimate the linear trend in Greenland ice mass during 2002–2004. We recover a decrease in total ice mass of 82 ± 28 km3 of ice per year, consistent with estimates from other techniques. Our uncertainty estimate is dominated by the effects of GRACE measurement errors and errors in our post glacial rebound (PG) correction. The main advantages of GRACE are that it is sensitive to the entire ice sheet, and that it provides mass estimates with only minimal use of supporting physical assumptions or ancillary data.
Spatial and temporal variations in the age structure of Arctic sea ice
Authors: Belchansky G. I. , Douglas D. C. , Platonov N. G.
Published: September 2005

Spatial and temporal variations in the age structure of Arctic sea ice are investigated using a new reverse‐chronology algorithm that tracks ice‐covered pixels to their location and date of origin based on ice motion and concentration data. The Beaufort Gyre tends to harbor the oldest (>10 years old) sea ice in the western Arctic while direct ice advection pathways toward the Transpolar Drift Stream maintain relatively young (≤5 years) ice in the eastern Arctic. Persistent net losses (−4.2% yr−1) in extent of ice >10 years old (10+ year age class) were observed during 1989–2003. Since the mid‐1990s, losses to the 10+ year age class lacked compensation by recruitment due to a prior depletion of all mature (6–10 year) age classes. Survival of the 1994 and 1996–1998 sea ice generations reestablished most mature age classes, and thereby the potential to increase extent of the 10+ year age class during the mid‐2000s.
Observation of NOx enhancement and ozone depletion in the Northern and Southern Hemispheres after the October–November 2003 solar proton events
Authors: López‐Puertas M. , Funke B. , Gil‐López S. , von Clarmann T. , Stiller G. P. , Höpfner M. , Kellmann S. , Fischer H. , Jackman C. H.
Published: September 2005

The large solar storms in October–November 2003 produced enormous solar proton events (SPEs) where high energetic particles reached the Earth and penetrated into the middle atmosphere in the polar regions. At this time, the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) was observing the atmosphere in the 6–68 km altitude range. MIPAS observations of NOx (NO + NO2) and O3 of the period from 25 October to 14 November 2003 are the first global measurements of NOx species, covering both the summer (daylight) and winter (dark) polar regions during an SPE. Very large values of NOx in the upper stratosphere of 180 ppbv (parts per billion by volume) have been measured, and a large asymmetry in northern and southern polar cap NOx enhancements was found. Arctic mean polar cap (>60°) NOx enhancements of 20 to 70 ppbv between 40 to 60 km lasted for at least 2 weeks, while the Antarctic mean NOx enhancement was between 10 and 35 ppbv and was halved after 2 weeks. Ozone shows depletion signatures associated with both HOx (H + OH + HO2) and NOx enhancements but at different timescales. Arctic lower mesospheric (upper stratospheric) ozone is reduced by 50–70% (30–40%) for about 2 weeks after the SPEs. A smaller ozone depletion signal was observed in the Antarctic atmosphere. After the locally produced Arctic middle and upper stratospheric as well as mesospheric NOx enhancement, large amounts of NOx were observed until the end of December. These are explained by downward transport processes. These enhancements drastically declined with the mid‐December stratospheric warming. Significant O3 depletion was observed inside the polar vortex in a wide altitude range during this period. From mid‐January until the end of March 2004, MIPAS observed extraordinary high values of NO2 in the upper stratosphere of the northern polar region (mean in‐vortex values up to 350 ppbv at ∼54 km), which seem to be caused by the unusually strong vortex and downward transport at that time together with an uncommonly large auroral activity starting with the solar storms in October–November and continuing over the winter. In‐vortex ozone was observed to significantly decline in the mid‐February to late March period above the 1750 K potential temperature level.
Temperature tides and waves near the mesopause from lidar observations at two latitudes
Authors: Fricke‐Begemann Cord , Höffner Josef
Published: October 2005

Daytime and nighttime temperature measurements covering several days enable the detection of tidal and wave perturbations in the mesopause region. This study presents two potassium lidar observations from 28°N and 54°N which cover more than 100 hours each. The temperature variations during this time show significant wave features, and numerical analyses allow to separate those of tidal and nontidal origin. The tidal activity under winter conditions is found to be dominated by upward propagating semidiurnal tides with amplitudes of about 10 K. Whereas a diurnal tide was also seen at 54°N, it was not detectable at 28°N. The data are discussed with respect to various available data sets and models. Comparisons with current numerical models show that especially the semidiurnal tide is clearly underestimated at both latitudes. The tidal activity exhibits a strong variability. This indicates nonlinear interactions with planetary waves, which have also been observed.
Escape from the double cone: Optimized descriptions of the seam space using gateway modes
Authors: Yarkony David R.
Published: September 2005

The conceptual description of nuclear dynamics near a conical intersection generally focuses on the branching plane, the two-dimensional subspace in which the conical topography is evinced, to the exclusion of the seam coordinates, the remaining internal nuclear coordinates. Establishing the limits of the utility of this assumption is an important issue in nonadiabatic dynamics. To accomplish this a careful treatment of the nuclear dynamics near conical intersections is required. The coordinate systems generally available for describing conical intersections are not optimal for such studies. In this work we extend a perturbative description of a conical intersection to describe more general seam spaces. We develop a coordinate system that segregates the interactions coupling the branching plane to the seam space into a set of gateway modes. The size of this set does not increase with the size of the molecule. The gateway modes are illustrated for the 1,2A1 conical intersections in NH3. The connection between the gateway modes and the optimum coordinate system for locating and characterizing seam confluences, intersections of two branches of the same seam, is discussed.
Coupled-cluster theory based upon the fragment molecular-orbital method
Authors: Fedorov Dmitri G. , Kitaura Kazuo
Published: September 2005

The fragment molecular-orbital (FMO) method was combined with the single-reference coupled-cluster (CC) theory. The developed method (FMO-CC) was applied at the CCSD and CCSD(T) levels of theory, for the cc-pVnZ family of basis sets (n=D,T,Q) to water clusters and glycine oligomers (up to 32 molecules/residues using as large basis sets as possible for the given system). The two- and three-body FMO-CC results are discussed at length, with emphasis on the basis-set dependence and three-body effects. Two- and three-body approximations based on interfragment distances were developed and the values appropriate for their accurate application carefully determined. The error in recovering the correlation energy was several millihartree for the two-body FMO-CC method and in the submillihartree range for the three-body FMO-CC method. In the largest calculations, we were able to perform the CCSD(T) calculations of (H2O)32 with the cc-pVQZ basis set (3680 basis functions) and (GLY)32 with the cc-VDZ basis set (712 correlated electrons). FMO-CC was parallelized using the upper level of the two-layer parallelization scheme. The computational scaling of the two-body FMO-CC method was demonstrated to be nearly linear. As an example of timings, CCSD(T) calculations of (H2O)32 with cc-pVDZ took 13min on an eight node 3.2-GHz Pentium4 cluster.