bluuebunny/crossref_metadata_2025 huggingface dataset:
Osmium‐Mediated CH and CC Bond Cleavage of a Phenolic Substrate: p‐Quinone Methide and Methylene Arenium Pincer Complexes
Authors: Gauvin Régis M. , Rozenberg Haim , Shimon Linda J. W. , Ben‐David Yehoshoa , Milstein David
Published: December 2006

The diphosphine 2,4,6‐(CH3)3‐3,5‐(iPr2PCH2)2C6OH (1) reacts with [OsCl2(PPh3)3] in presence of an excess of triethylamine to yield the isomeric para‐quinone methide derivatives [Os{4‐(CH2)‐1‐(O)‐2,6‐(CH3)2‐3,5‐(iPr2PCH2)2C6}(Cl)(H)(PPh3)] (2 and 3), which differ in the positions of the mutually trans hydride and chloride ligands. Complex 2 reacts with CO to afford the dicarbonyl species [Os{1‐(O)‐2,4,6‐(CH3)3‐3,5‐(iPr2PCH2)2C6}(Cl)(CO)2] (4), which results from hydride insertion into the quinonic double bond. Protonation of 2 and 3 leads to the formation of the methylene arenium derivative [Os{4‐(CH2)‐1‐(OH)‐2,6‐(CH3)2‐3,5‐(iPr2PCH2)2C6}(Cl)(H)(PPh3)][OSO2CF3] (5 a). The diphosphine 1 reacts with [OsCl2(PPh3)3] at 100 °C under H2 to afford [Os{1‐(OH)‐2,6‐(CH3)2‐3,5‐(iPr2PCH2)2C6}(Cl)(H2)(PPh3)] (6), a PCP pincer complex resulting formally from C(sp2)C(sp3) cleavage of the CCH3 group in 1. CC hydrogenolysis resulting in the same complex is achieved by heating 2 under H2 pressure. Reaction of the diphosphine substrate with [OsCl2(PPh3)3] under H2 at lower temperature allows the observation of a methylene arenium derivative resulting from CH activation, [Os{4‐(CH2)‐1‐(OH)‐2,6‐(CH3)2‐3,5‐(iPr2PCH2)2C6}(Cl)2(H)] (7). This compound reacts with PPh3 in toluene to afford the ionic derivative [Os{4‐(CH2)‐1‐(OH)‐2,6‐(CH3)2‐3,5‐(iPr2PCH2)2C6}(Cl)(H)(PPh3)]Cl (5 b). X‐ray diffraction studies have been carried out on compounds 2, 3, 4, 5 b, 6, and 7, which allows the study of the structural variations when going from methylene arenium to quinone methide derivatives.
Whole, Turret and step methods of rapid rescreening: Is there any difference in performance?
Authors: Montemor Eliana Borin Lopes , Roteli‐Martins Cecilia M. , Zeferino Luiz Carlos , Amaral Rita Goreti , Fonsechi‐Carvasan Gislaine Aparecida , Shirata Neuza Kasumi , Utagawa Maria Lúcia , Longatto‐Filho Adhemar , Syrjanen Kari J.
Published: December 2006

We compared the performance of the Whole, Turret and Step techniques of 100% rapid rescreening (RR) in detection of false‐negatives in cervical cytology. We tested RR performance with cytologists trained and among those without training. We revised 1,000 consecutive slides from women participating in an ongoing international screening trial. Two teams of experienced cytologists performed the RR techniques: one trained in RR procedures and the other not trained. The sensitivities in the trained group were Whole 46.6%, Turret 47.4% and Step 50.9%; and in the non‐trained group were 38.6, 31.6 and 47.4%, respectively. The κ coefficient showed a weak agreement between the two groups of cytologists and between the three RR techniques. The RR techniques are more valuable if used by trained cytologists. In the trained group, we did not observe significant differences between the RR techniques used, whereas in the non‐trained group, the Step technique had the best sensitivity. Diagn. Cytopathol. 2007;35:57–60. © 2006 Wiley‐Liss, Inc.
Weeding atypical glandular cell look‐alikes from the true atypical lesions in liquid‐based Pap tests: A review
Authors: Wood Moira D. , Horst Julie A. , Bibbo Marluce
Published: December 2006

The purpose of this review is to identify features that separate atypical glandular cells (AGC) associated with glandular neoplasia from its mimickers, both benign and neoplastic. We reviewed cases of AGC diagnosed on liquid‐based Pap tests (LBP) for which corresponding histological follow‐up was available. A review of the literature for similar studies in LBP tests was also conducted. We find that certain benign mimics can be reliably separated from AGC, but recommend caution in attempting to increase specificity at the risk of losing sensitivity.

Although accounting for only a small percentage of diagnoses AGC require a thorough clinical evaluation, including colposcopy. Most cases are ultimately found to be benign. When evaluating smears suspicious for AGC, it is important to examine the subtle features which make truly atypical cells discernible from their numerous benign mimickers. Diagn. Cytopathol. 2007;35:12–17. © 2006 Wiley‐Liss, Inc.
Fischer Indole Synthesis in Brønsted Acidic Ionic Liquids: A Green, Mild, and Regiospecific Reaction System
Authors: Xu Dan‐Qian , Yang Wen‐Long , Luo Shu‐Ping , Wang Bing‐Tao , Wu Jian , Xu Zhen‐Yuan
Published: December 2006

A novel one‐pot Fischer indole synthesis approach has been developed by using Brønsted acidic ionic liquids as dual solvent‐catalysts. Yields of 83–97 % were obtained after reaction in BMImHSO4 at 70–110 °C in 0.5–6 h, and exclusive formation of 2,3‐disubstituted indoles was observed in the reaction of alkyl methyl unsymmetrical ketones. The indoles produced could be conveniently separated from the reaction mixture without any volatile organic solvents, and the BMImHSO4 could be readily reused without efficiency loss after simple treatment involving only 1 equiv. of HCl for neutralization followed by filtration.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Three New Serratane Triterpenoids from Phlegmariurus squarrosus
Authors: Yan Jian , Cheng Bao‐Hui , Zhang Xian‐Min , Qiu Ming‐Hua
Published: December 2006

Three new serratane triterpenoids, (3α,14α,15α,21α)‐3,14,15,21,29‐pentahydroxyserratan‐24‐oic acid (1), (3α,21β)‐serrat‐14‐ene‐3,21,24,30‐tetraol (2), and (3α,21α)‐serrat‐14‐ene‐3,21,24,29‐tetraol (3), were isolated from Phlegmariurus squarrosus, together with eight known compounds. Their chemical structures were elucidated on the basis of in‐depth spectroscopic analyses.
Cadinene Derivatives from Eupatorium adenophorum
Authors: Wang Ming‐Zhong , Zhang Yan‐Yan , Li Shun‐Lin , Cai Xiang‐Hai , Luo Xiao‐Dong
Published: December 2006

A new norsesquiterpene named eupatorone (= (4S,4aR,6R)‐1‐acetyl‐6‐(acetyloxy)‐4,4a,5,6‐tetrahydro‐4,7‐dimethylnaphthalen‐2(3H)‐one; 1) and a new sesquiterpene derivative named 2‐deoxo‐2‐(acetyloxy)‐9‐oxoageraphorone (= (1R,4S,4aR,6R,8aS)‐6‐(acetyloxy)‐3,4,4a,5,6,8a‐hexahydro‐4,7‐dimethyl‐1‐(1‐methylethyl)naphthalen‐2(1H)‐one; 2), together with the five known cadinene derivatives 3–7 were isolated from the flower of Eupatorium adenophorum (Spreng.). Their structures were established by extensive NMR experiments, including 1D and 2D NMR.
RNAs everywhere: genome‐wide annotation of structured RNAs
Authors: Backofen Rolf , Bernhart Stephan H. , Flamm Christoph , Fried Claudia , Fritzsch Guido , Hackermüller Jörg , Hertel Jana , Hofacker Ivo L. , Missal Kristin , Mosig Axel , Prohaska Sonja J. , Rose Dominic , Stadler Peter F. , Tanzer Andrea , Washietl Stefan , Will Sebastian
Published: December 2006

Starting with the discovery of microRNAs and the advent of genome‐wide transcriptomics, non‐protein‐coding transcripts have moved from a fringe topic to a central field research in molecular biology. In this contribution we review the state of the art of “computational RNomics”, i.e., the bioinformatics approaches to genome‐wide RNA annotation. Instead of rehashing results from recently published surveys in detail, we focus here ontheopen problem in the field, namely (functional) annotation of the plethora of putative RNAs. A series of exploratory studies are used to provide non‐trivial examples for the discussion of some of the difficulties.J. Exp. Zool. (Mol. Dev. Evol.) 308B, 2007. © 2006 Wiley‐Liss, Inc.
Astroglia growth retardation and increased microglia proliferation by lithium and ornithine decarboxylase inhibitor in rat cerebellar cultures: Cytotoxicity by combined lithium and polyamine inhibition
Authors: Gilad Gad M. , Gilad Varda H.
Published: December 2006

Lithium, the most prevalent treatment for manic‐depressive illness, might have a neuroprotective effect after brain injury. In culture, lithium can exert neurotoxic effects associated with reduction in polyamine synthesis but neuroprotective effects as cultured neurons mature. Cumulative evidence suggests that lithium may exert some of its effects on neurons indirectly, by initially acting on glial cells. We used rat cerebellar cultures to ascertain the effects of lithium on ornithine decarboxylase (ODC) activity, the enzyme catalyzing the first step in polyamine synthesis, and to compare effects of lithium with those of the ODC inhibitor α‐difluoromethylornithine (DFMO) on neuron survival and glial growth. Switching cultures from high (25 mM) to low (5 mM) KCl concentrations served as the traumatic neuronal insult. The results indicate the following. 1) Whereas high depolarizing KCl concentration enhances neuron survival, it inhibits astroglial growth. 2) Lithium (LiCl; 1–5 mM) enhances neuronal survival but inhibits astroglial growth. 3) Lithium treatment leads to reduced ODC activity. 4) DFMO enhances neuron survival but inhibits astroglial growth. 5) Lithium and DFMO lead to transformation of astroglia from epithelioid (flat) to process‐bearing morphology and to increased numbers of microglia. 6) Combined lithium plus DFMO treatment is cytolethal to both neurons and glia in culture. In conclusion, lithium treatment results in growth retardation and altered cell morphology of cultured astroglia and increased microglia proliferation, and these effects may be associated with inhibition of polyamine synthesis. This implies that direct effects on astrocytes and microglia may contribute to the effects of lithium on neurons. © 2006 Wiley‐Liss, Inc.
Glutathione elevation by γ‐glutamyl cysteine ethyl ester as a potential therapeutic strategy for preventing oxidative stress in brain mediated by in vivo administration of adriamycin: Implication for chemobrain
Authors: Joshi Gururaj , Hardas Sarita , Sultana Rukhsana , St. Clair Daret K. , Vore Mary , Butterfield D. Allan
Published: December 2006

Oxidative stress in heart and brain by the cancer chemotherapeutic drug adriamycin (ADR), used for treating solid tumors, is well established. Long‐term treatment with ADR in breast cancer patients has led to symptoms of cardiomyopathy. Less well recognized, but increasingly well documented, is cognitive dysfunction. After chemotherapy, free radical‐mediated oxidative stress has been reported in both heart and brain. We recently showed a significant increase in protein oxidation and lipid peroxidation in brain isolated from mice injected intraperitonially (i.p) with ADR. Systemic administration of ADR also induces tumor necrosis factor‐α (TNF‐α), which leads to production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in brain. Circulating TNF also causes mitochondrial dysfunction, leading to apoptotic pathways in brain. Inducible nitric oxide synthase also plays a role in ADR‐induced TNF‐mediated neurotoxicity. In addition, we previously showed a significant decrease in glutathione (GSH) levels in brain isolated from ADR injected mice, along with increased expression of multidrug‐resistant protein‐1 (MRP‐1), glutathione‐S‐transferase (GST), glutathione peroxidase (GPx), and glutathione reductase (GR). There was a significant decrease in activity of brain GST. The present study was designed to test the hypothesis that, by elevating brain levels of GSH, the brain would be protected against oxidative stress in ADR‐injected mice. γ‐Glutamyl cysteine ethyl ester (GCEE), a precursor of glutathione, injected i.p. (150 mg/ kg body weight) 4 hr prior ADR injection (20 mg/kg body weight) led to significantly decreased protein oxidation and lipid peroxidation in subsequently isolated mice brain compared with brain isolated from ADR‐injected mice without GCEE. The GSH levels were restored to the level of brain isolated from saline‐injected mice. Furthermore, the enzyme activity of GST was increased in brain isolated from ADR‐injected mice previously injected with GCEE compared with the brain isolated from ADR‐injected mice previously injected with saline. These results are discussed with regard to potential pharmacological prevention of brain cognitive dysfunction in patients receiving ADR chemotherapy. © 2006 Wiley‐Liss, Inc.
An effective traffic management scheme using adaptive handover time in next‐generation cellular networks
Authors: Kim Dongwook , Sawhney Mrinalini , Yoon Hyunsoo
Published: December 2006

Next‐generation cellular networks are expected to support various multimedia services over IP networks with high spectral efficiency. In these networks, hotspot cells can occur when available wireless resources at some location are not sufficient to sustain the needs of users. The hotspot cell can potentially lead to blocked or dropped calls, which can deteriorate the service quality for users. A group of users enjoying multimedia services could move around in the networks generating heavy flows of traffic. This situation can generate a hotspot cell which has a short lifespan of only a few minutes. If there is a steady increase in the number of these users, the hotspot cell which has a short lifespan will occur more frequently in the overall service area. In this paper, we propose a handover‐based traffic management scheme which can effectively deal with hotspot cells in next‐generation cellular networks. With our scheme, the current serving cell can recognize the traffic load status of the target cell in advance, before handover execution. Then, according to the load status, it adaptively controls the handover time. The handover‐based traffic management scheme can effectively and flexibly handle hotspot cells in the networks. Acceptable service quality can also be supported as users continuously maintain communication links. In the simulation results, we find that our scheme generates a smaller number of hotspot cells and supports higher service quality than the schemes compared. Copyright © 2006 John Wiley & Sons, Ltd.
Polycondensation of activated L‐valine and L‐leucine esters with various lewis acids
Authors: Nemoto Tadamasa , Ando Daisuke , Naka Kensuke , Chujo Yoshiki
Published: December 2006

To develop a novel polycondensation method for the preparation of poly (amino acid)s, we screened a transition metal or a rare‐earth triflate as a Lewis acid for the polycondensation of activated amino acid esters in N,N‐dimethylformamide solutions at room temperature. The polymerizations of 4‐nitrophenyl L‐leucinate (1a) and 4‐nitrophenyl L‐valinate (1b) scarcely proceeded without any Lewis acid at room temperature. In the presence of 5 mol % metal triflates, especially scandium(III) trifluoromethanesulfonate, the polymerizations of both monomers were promoted effectively. The products, which were collected by the reaction mixture being poured into water, were recognized as poly(L‐valine)s by Fourier transform infrared spectroscopy, gel permeation chromatography analysis, and 1H NMR spectroscopy. These results showed that a metal triflate as a Lewis acid could coordinate to a carbonyl oxygen of activated L‐valinate and L‐leucinate even in a highly polar solvent, such as N,N‐dimethylformamide; therefore, the polymerizations of activated L‐valinate and L‐leucinate were promoted. Because steric hindrance derived from the isobutyl group in 1b was less than that of the isopropyl unit in 1a, the effect of the metals was not as sensitive for the polymerization of 1b. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 543–547, 2007
Structure and properties of a truely apo form of AraC dimerization domain
Authors: Weldon John E. , Rodgers Michael E. , Larkin Christopher , Schleif Robert F.
Published: December 2006

The arabinose‐binding pockets of wild type AraC dimerization domains crystallized in the absence of arabinose are occupied with the side chains of Y31 from neighboring domains. This interaction leads to aggregation at high solution concentrations and prevents determination of the structure of truely apo AraC. In this work we found that the aggregation does not significantly occur at physiological concentrations of AraC. We also found that the Y31V mutation eliminates the self‐association, but does not affect regulation properties of the protein. At the same time, the mutation allows crystallization of the dimerization domain of the protein with only solvent in the arabinose‐binding pocket. Using a distance difference method suitable for detecting and displaying even minor structural variation among large groups of similar structures, we find that there is no significant structural change in the core of monomers of the AraC dimerization domain resulting from arabinose, fucose, or tyrosine occupancy of the ligand‐binding pocket. A slight change is observed in the relative orientation of monomers in the dimeric form of the domain upon the binding of arabinose but its significance cannot yet be assessed. Proteins 2007. © 2006 Wiley‐Liss, Inc.
Aquatic fulvic acid as a matrix for matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometric analysis
Authors: Mugo Samuel M. , Bottaro Christina S.
Published: December 2006

Aquatic fulvic acids (AFAs) are demonstrated to be effective matrices for the analysis of various polar compounds (ranging from 100–1500 Da) by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS). The efficiency of AFA as a matrix is shown for a wide range of test compounds, including a number of carbohydrates, cyclodextrins and peptides, with typical detection limits of ∼10 µg mL−1. The propensity of AFA to enhance ionization through protonation of peptides, and formation of sodium and potassium adducts of carbohydrates and polyethylene glycol, was noted. Differences were observed in the performances of the two AFA matrices used, a Suwannee River, International Humic Substances Society (IHSS) standard and a locally extracted fulvic acid (LFA). For example, in the analysis of carbohydrate standards, the use of the LFA matrix typically doubled the analyte ion signal intensities and resulted in signal‐to‐noise (S/N) ratios that were 2–4 times better than when the Suwannee River AFA matrix was used. AFA was also used in the analysis of real‐world samples without extraction or purification; cantaloupe juice and acetaminophen tablets were analyzed, and glucose and acetaminophen could easily be identified as respective components. When lower concentrations of fulvic acid were used in the presence of sugars, a reversal of roles was observed in which the sugars functioned as the matrix and significantly enhanced ionization of the AFA components, while ions associated with the sugars themselves were suppressed or absent. Effective as a matrix for a variety of analytes and widely available, AFA is an attractive environmentally friendly choice for use in MALDI applications. Copyright © 2006 John Wiley & Sons, Ltd.
The use of stable isotope ratio analyses to discriminate wild and farmed gilthead sea bream (Sparus aurata)
Authors: Rojas Jose Manuel Moreno , Serra Francesca , Giani Ivan , Moretti Vittorio M. , Reniero Fabiano , Guillou Claude
Published: December 2006

Continuous flow isotope ratio mass spectrometry (CF‐IRMS) has been used to analyze samples of gilthead sea bream (g.s.b.) (Sparus aurata) of known geographical origin (four countries on the Mediterranean Sea) from wild and farmed sources (40 farmed and 10 wild). δ13C and δ15N values have been measured on muscle samples as these are the most informative parameters of the diet of the animals. Both stable isotopes are indicators of the origin of the fish: δ13C giving a tool to distinguish between wild and farmed g.s.b. and δ15N being more informative on the geographical origin of the fish (this fact could be related more to differences in feed mixtures given to farmed fish than to geographical reasons). The proposed methodology offers a cost‐ and time‐effective alternative to other analytical techniques in identifying wild and farmed fish. Copyright © 2006 John Wiley & Sons, Ltd.
Acoustically Driven Programmable Microfluidics for Biological and Chemical Applications
Authors: Wixforth Achim
Published: December 2006

A novel approach toward the needs of a versatile chip-based microfluidic system with unique properties and functionality is reviewed. Like for microarrays and in contrast to many existing technologies, the fluid handling is performed on the flat surface of a programmable chip, where fluidic tracks and functional blocks such as valves, dispensers, mixers, and sensing elements are chemically defined using standard lithographic techniques. The actuation of the fluid, the driving and addressing of the functional elements as well as possible sensors are based on electrically excited mechanical surface acoustic waves, propagating along the surface of a chip. Based on this acoustically driven microfluidic technique, a variety of different chips but also lab equipment has been devised, including a chip-based PCR reactor, microarray hybridization chambers, and noninvasive miniature mixers for cuvette and micro titerplate applications.
Protein Transport and Concentration by Electrophoresis in Two-phase Microflows
Authors: Münchow G. , Hardt S. , Kutter J.P. , Drese K.S.
Published: December 2006

This work aims at a new class of methods for electric field-mediated separation of biomolecules. In contrast to standard techniques, electrophoretic transport was not performed in a single-phase homogenous fluid, but in a system of stratified layers. The large surface-to-volume ratio characteristic for microfluidic systems allows the interactions of biomolecules with liquid/liquid interfaces to be examined and the suitability of corresponding effects for applications in the field of biomolecular separations and enrichment to be assessed. To perform these types of studies, a micro flow cell was fabricated into which two coflowing immiscible liquid phases can be introduced. Subsequently, the electrophoretic transport of biomolecules driven by an electric field perpendicular to the channel was examined.

To investigate the transport phenomena related to electrophoresis in stratified two-phase systems, aqueous solutions consisting of polyethylene glycol and dextran were prepared, which allowed a stable interface to develop. Transport within one phase and an enrichment of proteins at the phase boundary has been established. In addition, other kinds of fluid combinations such as water and propylene carbonate have been examined, also supporting the enrichment of proteins at the phase boundary.
Functional relationships and bio-optical properties derived from phytoplankton pigments, optical and photosynthetic parameters; a case study of the Benguela ecosystem
Authors: Fishwick James R. , Aiken Jim , Barlow Ray , Sessions Heather , Bernard Stuart , Ras Josephine
Published: December 2006

The relationships between phytoplankton pigments, optical properties and photosynthetic parameters for different phytoplankton functional types (derived by diagnostic pigment indices, DPI) were determined from data acquired in the Benguela ecosystem and the offshore region in October 2002. We observed robust inter-pigment relationships: total chlorophyll-a (TChla) was highly correlated with total pigment (TP) and accessory pigment (AP). However, the regression equations for stations dominated by flagellates differed from the equations for stations dominated by diatoms and dinoflagellates. The pigment ratio TChla/TP and the optical ratio a676/a440 were not constant but increased non-linearly with increasing TChla or TP; complimentarily the AP/TP and a490/a676 ratios decreased. There were significant non linear relationships between the photosynthetic parameters Fv/Fm or σPSII measured by Fast Repetition Rate Fluorometry and TChla or TP. Pigment ratios, optical ratios, Fv/Fm and σPSII were all inter-correlated with high significance. We determined the distinctive bio-optical properties associated with dominant phytoplankton functional types (derived by DPI) that conformed to the classical partitioning: flagellates (nano-plankton, comprising several taxa) had low biomass,low TChla/TP fraction and low Fv/Fm and high σPSII; diatoms and dinoflagellates (micro-plankton) had high biomass, pigment ratios, Fv/Fm and low σPSII.
Evidence of seasonal reproduction in the Atlantic vent mussel Bathymodiolus azoricus, and an apparent link with the timing of photosynthetic primary production
Authors: Dixon D.R. , Lowe D.M. , Miller P.I. , Villemin G.R. , Colaço A. , Serrão-Santos R. , Dixon L.R.J
Published: December 2006

Here we present evidence of seasonal reproduction in the deep-sea vent mussel Bathymodiolus azoricus, a dominant member of the Mid-Atlantic Ridge (MAR) hydrothermal fauna in the Azores region. This is the first time that seasonal reproduction has been suggested for any deep-sea vent organism. This discovery was made possible by the use of novel, acoustically-retrievable cages, which allowed us to extend the frequency and temporal range of sampling that was previously limited to the summer months. The main spawning peak, at the Menez Gwen vent field (840 m) occurs in late December–January and shows a correlation with a winter–spring bloom in primary production in the euphotic zone. Our results suggest that this surface-derived material may act as both a food source for the dispersing mussel larvae and as a reproductive cue/supplementary nutritional source for the adult mussels. Further evidence of a dependence on photosynthetic inputs comes from the relationship between particulate feeding levels, which themselves correlate with the phytoplankton peak, and the amounts of storage tissue in the mantle, which ultimately gets converted into gonad. Thus, the pattern and energetics of reproduction in the Atlantic vent mussel B. azoricus closely resembles that found in the coastal mussel Mytilus edulis, which has been described as an adaptation for optimizing the timing of reproduction against a background of seasonally-varying food availability. This discovery emphasizes the complexity of the nutritional pathways found in some deep-sea chemosynthetic environments and highlights the need for more time-series studies.
Life history and reproductive biology of the invasive amphipod Melita palmata (Amphipoda: Melitidae) in the Mar Chiquita coastal lagoon, Argentina
Authors: Obenat S. , Spivak E. , Garrido L.
Published: December 2006

The life history and reproductive biology of the gammaridean amphipod Melita palmata was studied in the Mar Chiquita coastal lagoon (Argentina). The animals were collected fortnightly or monthly from Ficopomatus enigmaticus reefs from December 2000 to March 2002. The population density reached a maximum of 1556.67±1560 ind/m3 (mean±SD) in March 2001, decreased dramatically after intense rainfalls in winter 2001, and had a minimum value of 141.67±27.54 ind/m3 (mean±SD) in March 2002. Size differed significantly between sexes. The maximum size of males was 11.5 mm and this was 1.4 times longer than the length of females. The average sex ratio (0.44) did not differ significantly from an expected 1:1 value. Ovigerous females were present from December to March, when the temperature was above 18°C. The body size of ovigerous females ranged from 2.9 to 6.81 mm. There was a positive correlation between the brood size and body length of ovigerous females, and the maximum number of eggs per female was ten. Recruitment took place during the whole breeding season; juveniles recruited at the beginning of the season matured at the end of the same season, those recruited late would probably reach maturity in the following season.
Abundance of demersal fish resources in the Persian Gulf and Oman Sea
Authors: Valinassab T. , Daryanabard R. , Dehghani R. , Pierce G.J.
Published: December 2006

We report on results of a trawl survey during 2003–2004 to assess the abundance of demersal fish resources in the Persian Gulf and Oman Sea. Samples were taken at a total of 316 trawl stations selected following a stratified random procedure. Catch rates (catch per unit area, CPUA) and total biomass were estimated. Total demersal fish biomass was estimated to be approximately 73,000 tonnes in Persian Gulf waters and approximately 39,000 tonnes in the Oman Sea. The lowest CPUA was recorded in the west of the study area (stratum A, approximately 1700 kg/n.m.2) and the highest in the east (stratum Q, 13943.4 kg/n.m.2), although density of commercially important species was higher in the central area (stratum K). Catch rate and biomass varied significantly in relation to seabed depth. Commercially important demersal species made up around 60% of the estimated total biomass. The most abundant species groups were rays, catfish, grunts, nemipterids and carangids. Several important species (e.g. silver pomfret, croakers and sharks) appear to have declined since the late 1970s while others, such as rays and catfish, have increased.
MULTIVARIATE STOCHASTIC COMPARISONS OF SEQUENTIAL ORDER
STATISTICS
Authors: Zhuang Weiwei , Hu Taizhong
Published: December 2006

In this article we investigate conditions on the underlying
distribution functions on which the sequential order statistics are based,
to obtain stochastic comparisons of sequential order statistics in the
multivariate likelihood ratio, the multivariate hazard rate, and the usual
multivariate stochastic orders. Some applications of the main results are
also given.
Attitude Estimation By Divided Difference Filter-Based Sensor Fusion
Authors: Peyman Setoodeh , Alireza Khayatian , Ebrahim Farjah
Published: December 2006

Strapdown inertial navigation systems (INS) often employ aiding sensors to increase accuracy. Nonlinear filtering algorithms are then needed to fuse the collected data from these aiding sensors with measurements of strapdown rate gyros. Aiding sensors usually have slower dynamics compared to gyros and therefore collect data at lower rates. Thus the system will be unobservable between aiding sensors' sampling instants, and the error covariance, which shows the uncertainty in the estimation, grows during the sampling period. This paper presents a divided difference filter (DDF)-based data fusion algorithm, which utilizes the complementary noise profile of rate gyros and gravimetric inclinometers to extend their limits and achieve more accurate attitude estimates. It is confirmed experimentally that DDF achieves better covariance estimates compared to the extended Kalman filter (EKF) because the uncertainty in the state estimate is taken care of in the DDF polynomial approximation formulation.
Building the Latitude Equation of the Mid-longitude
Authors: Tseng Wei-Kuo , Lee Hsuan-Shih
Published: December 2006

We were amused by the Cross Track Distance at Mid-Longitude problem posed by Paul Hickley in The Journal of Navigation 57, 320. Two professors, John Ponsonby and Peter Hoare, replied to the invitations immediately. Both their solutions to the original article give superb accuracy. The two solutions are certainly ingenious and creative and encouraged us to develop new formula for building the Mid-Longitude Equation on great circle. Regrettably, the original author doesn’t think that the two were the solution that ATPL examiners were looking for. I also think that the two solutions would be beyond the capacity of the average undergraduate. Our method gives a good understanding logically and easily to be mnemonic, and the derivation process is found without any need to appeal to any formula of spherical trigonometry.
A Microcarrier‐Based Cultivation System for Expansion of Primary Mesenchymal Stem Cells
Authors: Frauenschuh Simone , Reichmann Elisabeth , Ibold Yvonne , Goetz Peter M. , Sittinger Michael , Ringe Jochen
Published: December 2006

Microcarrier cultures have been shown to allow extensive cell expansion of tissue engineering relevant cells, such as chondrocytes, while maintaining their phenotype. Our aim was to investigate the in vitro three‐dimensional expansion of porcine bone‐marrow‐derived primary mesenchymal stem cells (MSC) using commercially available Cytodex type 1, type 2, and type 3 microcarriers. In comparison, the Cytodex type 1 microcarriers showed the best results for adherence with over 80% adherent cells after 3 h of incubation, analyzed by the Poisson distribution. Different start cell densities ranging from 1 to 3 × 106 cells per 100 cm2 had only a minor influence on adhesion. The proliferation was examined on Cytodex type 1 microcarriers over a cultivation time of 28 days, which could reveal cell growth and proof of cells recolonizing freshly added microcarriers. Scanning electron microscopy displayed appropriate cell morphology and confirmed cell proliferation. After enzymatic harvest from microcarriers, the osteogenic and chondrogenic differentiation of these cells was induced and shown by relevant histochemistry, such as von Kossa and Alcian blue staining. Totaling the results, we have shown that the three‐dimensional expansion of MSC on microcarriers represents a beneficial alternative to the conventional two‐dimensional monolayer cultivation method.
Principles that People Seek to Avoid in Their Lives
Authors: Aavik Toivo , Allik Jüri
Published: December 2006

This study concerns the interrelationship between positive and negative values. Previous research has treated personal values as a bipolar process in which negative values can be described merely as desired values with the opposite sign. Contrary to values research, the study of motivation has shown that approach motivation is conceptually distinctive from the motivation of avoidance. The results revealed that, in general, level positive and negative values form two opposite domains that are not completely independent. On a more specific level of analysis the structure of negative values did not mirror the structure of positive values: They formed a single general negativity factor, which had no significant loadings on any of the six positive value factors.
Radial diffusion and MHD particle simulations of relativistic electron transport by ULF waves in the September 1998 storm
Authors: Fei Yue , Chan Anthony A. , Elkington Scot R. , Wiltberger Michael J.
Published: December 2006

In an MHD particle simulation of the September 1998 magnetic storm the evolution of the radiation belt electron radial flux profile appears to be diffusive, and diffusion caused by ULF waves has been invoked as the probable mechanism. In order to separate adiabatic and nonadiabatic effects and to investigate the radial diffusion mechanism during this storm, in this work we solve a radial diffusion equation with ULF wave diffusion coefficients and a time‐dependent outer boundary condition, and the results are compared with the phase space density of the MHD particle simulation. The diffusion coefficients include contributions from both symmetric resonance modes (ω ≈ mωd, where ω is the wave frequency, m is the azimuthal wave number, and ωd is the bounce‐averaged drift frequency) and asymmetric resonance modes (ω ≈ (m ± 1)ωd). ULF wave power spectral densities are obtained from a Fourier analysis of the electric and magnetic fields of the MHD simulation and are used in calculating the radial diffusion coefficients. The asymmetric diffusion coefficients are proportional to the magnetic field asymmetry, which is also calculated from the MHD field. The resulting diffusion coefficients vary with the radial coordinate L (the Roederer L‐value) and with time during different phases of the storm. The last closed drift shell defines the location of the outer boundary. Both the location of the outer boundary and the value of the phase space density at the outer boundary are time‐varying. The diffusion calculation simulates a 42‐hour period during the 24–26 September 1998 magnetic storm, starting just before the storm sudden commencement and ending in the late recovery phase. The differential flux calculated in the MHD particle simulation is converted to phase space density. Phase space densities in both simulations (diffusion and MHD particle) are functions of Roederer L‐value for fixed first and second adiabatic invariants. The Roederer L‐value is calculated using drift shell tracing in the MHD magnetic field, and particles have zero second invariant. The radial diffusion calculation reproduces the main features of the MHD particle simulation quite well. The symmetric resonance modes dominate the radial diffusion, especially in the inner and middle L region, while the asymmetric resonances are more important in the outer region. Using both symmetric and asymmetric terms gives a better result than using only one or the other and is better than using a simple power law diffusion coefficient. We find that it is important to specify the value of the phase space density on the outer boundary dynamically in order to get better agreement between the radial diffusion simulation and the MHD particle simulation.
A simple statistical‐dynamical downscaling scheme based on weather types and conditional resampling
Authors: Boé J. , Terray L. , Habets F. , Martin E.
Published: December 2006

A multivariate statistical downscaling methodology is implemented to generate local precipitation and temperature series at different sites based on the results from a variable resolution general circulation model. It starts from regional climate properties to establish discriminating weather types for the chosen local variable, precipitation in this case. Intratype variations of the relevant forcing parameters are then taken into account by multivariate regression using the distances of a given day to the different weather types as predictors. The final step consists of conditional resampling. The methodology is evaluated in the Seine basin in France. Using reanalysis fields as predictors, satisfying results are obtained at daily timescale and concerning low‐frequency variations, both for temperature and precipitation. The use of model results as predictors gives a realistic representation of regional climate properties. Nevertheless, as the validation of a statistical downscaling algorithm for present day climate conditions does not necessarily imply the validity of its climate change projections, the plausibility of the downscaled climate projections is assessed by verifying the consistency between spatially averaged downscaled results and direct model outputs for two climate change scenarios. Despite some discrepancies for precipitation with the more extreme scenario, the consistency is good for both local variables. This result reinforces the confidence in the use of the downscaling scheme in altered climates. Finally, it is shown that the intertype variations of the atmospheric circulation represent only a fraction of the climate change signal for the local variables. Thus a downscaling methodology based on weather typing should incorporate information concerning intratype modifications.
Sensitivity of global tropospheric ozone and fine particulate matter concentrations to climate change
Authors: Racherla Pavan Nandan , Adams Peter J.
Published: December 2006

An integrated global model of climate, tropospheric gas phase chemistry, and aerosols has been used to investigate the sensitivity of global ozone and fine particulate matter concentrations to climate change. Two simulations corresponding to present (1990s) and future (2050s) climates have been performed and compared. A future climate has been imposed using ocean boundary conditions corresponding to the Intergovernmental Panel on Climate Change SRES A2 scenario for the 2050s decade, resulting in an increase in the global annual average values of the surface air temperature by 1.7°C, the lower tropospheric specific humidity by 0.9 g H2O/kg air, and the precipitation by 0.15 mm d−1. Present‐day anthropogenic emissions have been used in both simulations while climate‐sensitive natural emissions were allowed to vary with the simulated climate. The tropospheric ozone burden in the future climate run decreased by 5%, and its lifetime decreased from 27.8 to 25.3 days. The tropospheric ozone change is driven primarily by increased ozone loss rates through ozone photolysis in the presence of water vapor, which on a global scale, more than compensate for the increased ozone chemical production associated with increased temperatures. At the model surface layer, over remote regions, ozone mixing ratios decreased by 1–3 ppbv, while polluted regions showed a relatively smaller decrease of 0–1 ppbv and increased by 1–5 ppbv in some cases. The global burdens and lifetimes of fine particulate matter species in the future climate run decreased by 2 to 18% because of increased wet deposition loss rates associated with increased precipitation. At the model surface layer, there are regions of decreases and increases in the concentrations of fine particulate matter species. The increased surface layer concentrations of some fine particulate matter species is primarily driven by lower regional‐scale precipitation and increased secondary production, where applicable. The robustness of the predicted regional‐scale changes for fine particulate matter species is strongly dependent upon the predicted regional‐scale precipitation changes.
On the behavior of O+5 in coronal holes: Importance of sunward propagating waves
Authors: Hollweg Joseph V.
Published: December 2006

The high thermal anisotropy of O+5 in coronal holes, as observed by the Ultraviolet Coronagraph Spectrometer (UVCS) on the Solar and Heliospheric Observatory (SOHO), suggests that these ions are being heated by the cyclotron resonance. The observations indicate that the O+5 temperature steadily increases from r ≈ 1.5 rS (where the ions become almost collisionless) out to r ≈ 3.5 rS (the outer limit of the observations). Previous models have not been able to reproduce even the qualitative result of a steady temperature rise. We suggest that the problem has been that previous models have considered O+5 resonating only with outward propagating waves. Once the ions are heated perpendicularly to the background magnetic field, they are accelerated to high outward flow speeds by the mirror force. As a result, they resonate with outgoing waves having higher (normalized) wave numbers, where there is presumably less power; they may even drop out of resonance altogether. We suggest here that resonances with inward (i.e., sunward) propagating waves may be the key to explaining the observed O+5 temperature rise. In that case, as the ions are accelerated by the mirror force, they never drop out of resonance, and they resonate with ingoing waves having lower (normalized) wave numbers where there is presumably more power. We offer a very simple strawman model to illustrate the differences between oxygen resonances with ingoing and outgoing waves and to show that the UVCS/SOHO results can be approximately reproduced if the ingoing wave power spectrum in the resonant range varies as k−γ, with γ ≈ 5/3. We point out that it is really necessary to take into account the fact that O+5 (and other heavy ions) can resonate with ingoing and outgoing waves simultaneously, which can only be studied via full kinetic solutions for the ion distribution functions; however, it is possible that once the ions are accelerated by the mirror force, the resonances with sunward propagating waves will be dominant.
Kink instability of flux ropes anchored at one end and free at the other
Authors: Lapenta Giovanni , Furno Ivo , Intrator Thomas , Delzanno Gian Luca
Published: December 2006

The kink instability of a magnetized plasma column (flux rope) is a fundamental process observed in laboratory and in natural plasmas. Previous theoretical, experimental, and observational work has focused either on the case of periodic (infinite) ropes (relevant to toroidal systems) or on finite ropes with both ends tied to a specified boundary (relevant to coronal ropes tied at the photosphere). However, in the Sun's corona and in astrophysical systems there is an abundant presence of finite flux ropes tied at one end but free at the other. Motivated by recent experiments conducted on the RSX device (Furno et al., 2006) and by recent theoretical work (Ryutov et al., 2006), the present paper investigates by simulation the linear and nonlinear evolution of free‐ended flux ropes. The approach is based on comparing the classic case of a periodic flux rope with the case of a rope tied at one end and free at the other. In the linear phase, periodic and free ropes behave radically differently. A simulation analysis of the linear phase confirms the experimental and phenomenological findings relative to an increased instability of a free rope: the new stability limit is shown to be just half of the classic limit for periodic ropes. In the nonlinear phase, reconnection is observed to be a fundamental enabler to reach the eventual steady state. The mechanism for saturation of a flux rope is investigated and compared with the classic theory (the so‐called bubble state model) by Rosenbluth et al. (1976). A remarkable agreement is found for the classic periodic case. The case of a free rope is again very different. The saturated state is observed to present a outwardly spiraling configuration with the displacement of the plasma column increasing progressively and monotonically from the tied end to the free end. The maximum displacement is observed at the free end where it is consistent with the displacement observed in a periodic rope. The key distinction is that in a periodic rope the same displacement is observed throughout the whole rope to form a helix with constant radius.
Characterization of atmospheric aerosols at Monte Cimone, Italy, during summer 2004: Source apportionment and transport mechanisms
Authors: Marenco F. , Bonasoni P. , Calzolari F. , Ceriani M. , Chiari M. , Cristofanelli P. , D'Alessandro A. , Fermo P. , Lucarelli F. , Mazzei F. , Nava S. , Piazzalunga A. , Prati P. , Valli G. , Vecchi R.
Published: December 2006

Atmospheric aerosols in the PM10 and PM1 fractions have been sampled at the Global Atmospheric Watch station Mount Cimone, Italy (2165 m above mean sea level) for 3 months during summer 2004, and simultaneous size distributions have been derived by means of an optical particle counter. Samples have been analyzed by X‐ray fluorescence, ion chromatography, and thermal‐optical methodology in order to quantify their elemental, ionic, and carbonaceous constituents. The concentration of PM10 was 16.1 ± 9.8 μg m−3 (average and standard deviation). Source apportionment allowed us to identify, quantify and characterize the following aerosol classes: anthropogenic pollution (10 μg m−3), mineral dust (4 μg m−3), and sea salt (0.2 μg m−3). Pollution has been further split into ammonium sulfate (44%), organic matter (42%), and other compounds (14%). The nitrate/sulfate ratio in the polluted aerosol was 0.1. Fine particles have been completely related to the polluted aerosol component, and they represented 70% in weight of pollution. Coarse particles characterized the dust and salt components, and crustal oxides have been found to be the largest responsible for the aerosol concentration variations that occurred during the campaign. Nitrate has also been found in the coarse particles, representing ∼10% of mineral dust. The analysis of the transport mechanisms responsible for aerosol fluctuations permitted us to identify the origin of the major aerosol components: Pollution has been ascribed to regional transport driven by boundary layer meteorology, whereas mineral dust has been related to long‐range transport events originating in the Sahara and Sahel. A particularly significant Saharan episode has been identified on 10 August 2004 (PM10 daily concentration, 69.9 μg m−3). Average elemental ratios for the African dust events were as follows: Si/Al = 2.31, Fe/Ca = 0.94, Ca/Al = 0.90, K/Ca = 0.44, Ti/Ca = 0.11, and Ti/Fe = 0.12.