bluuebunny/crossref_metadata_2025 huggingface dataset:
The Synthesis of 3,5‐Diamino‐1,2,4‐oxadiazoles. 1st Communication
Authors: Tilley Jefferson W. , Ramuz Henri
Published: December 2004

Reaction of the 1‐substituted‐3‐cyano‐isothioureas 6 with hydroxylamine gave mixtures of the 5‐amino‐3‐substituted‐amino‐1,2,4‐oxadiazoles 1 and the isomeric 3‐amino‐5‐substituted‐amino‐1,2,4‐oxadiazoles 8 in which 1 usually predominated. The structural assignment of these products is discussed. In a second method, the 2‐hydroxy‐1‐methyl‐1‐phenyl‐guanidine 15 was converted to the corresponding 3‐disubstituted‐amino‐5‐trichloromethyl‐1,2,4‐oxadiazole 16, a precursor to the 5‐amino derivatives 17 by nucleophilic displacement of the trichloromethyl group.
9, 10‐Secocholesta‐(5Z)‐5,8(14), 10(19)‐trien‐3β‐ol und 18‐Nor‐14β‐methyl‐9,10‐secocholesta‐(5E)‐5, 10(19), 13(17)‐trien‐3β‐ol, zwei neue Doppelbindungsisomere des Vitamins D3. Strukturelle Abwandlungen am Vitamin D3: 5. Mitteilung [1]
Authors: Reischl Wolfgang , Zbiral Erich
Published: December 2004

9,10‐Secocholesta‐(5Z)‐5,8(14),10(19)‐triene‐3β‐ol and 18‐Nor‐14β‐methyl‐9,10‐secocholesta‐(5E)‐5,10(19), 13(17)‐trien‐3β‐ol, two new double bond isomers of vitamin D3. Structural modifications of vitamin D3: 5. Communication [1]

The present paper reports the synthesis and structure elucidation of the two title compounds. Treatment of the 4‐phenyl‐1,2,4‐triazolin‐3,5‐dione adducts of vitamin D3 with BF3O (C2H5)2 and KOH/butanol yields these two new vitamin D3 double bond isomers.
Synthesen von Tricyclo [5.2.1.04,8]decan (2‐Homobrendan)
Authors: Jäggi Franz Josef , Buchs Peter , Ganter Camille
Published: December 2004

Syntheses of Tricyclo [5.2.1.04,8]decane (2‐Homobrendane)

Three different approaches to tricyclo [5.2.1.04,8] decane (5) (and derivatives thereof), one of the 19 isomeric hydrocarbons of the ‘adamantaneland’, are described: (1) Cyclization of properly functionalized bicyclo [3.2.1]octanes as 32(cyclialkylation), 40+42 (thermocyclization) and 44+45 (photocyclization); (2) Silver‐(I)‐ion catalyzed rearrangement of 5,7‐ and 5,10‐Dehydroprotoadamantane (63 and 64, respectively) yielding tricyclo[5.2.1.04,8]dec‐2‐ (39) and ‐5‐ene (59), respectively; (3) Thermal eliminative rearrangement of the 10endo‐p‐toluenesulfonate and ‐methanesulfonate of protoadamantane (71 and 72) and protoadamant‐4‐ene (76 and 77), respectively, yielding tricyclo [5.2.1.04,8]dec‐2‐ene (39) and ‐2, 5‐diene (15), respectively.
Zur Kinetik des Ringschlusses von 2‐Hydroxybenzaniliden zu Benzoxazolen
Authors: Seha Zdenek
Published: December 2004

Kinetics of Cyclization of 2‐Hydroxybenzanilides to Benzoxazoles

The reaction rates of cyclization of 2‐hydroxybenzanilides to benzoxazoles have been measured in N‐methyl‐2‐pyrrolidone at different temperatures. The reactions follow second‐order kinetics.
Influence de composés à hétérocycle azoté et particulièrement d'azoles non condensés sur des réactions «prébiotiques» de condensation d'acides α‐aminés induites par les polyphosphates en milieu aqueux
Authors: Rabinowitz Joseph , Hampai Aioub
Published: December 2004

Influence of Nitrogen Heterocyclic Compounds and of Non Condensed Azoles in Particular on ‘Prebiotic’ Condensation Reactions of α‐Amino Acids Induced by Polyphosphates in Aqueous Solution

In previous experiments aqueous solutions of α‐aminoacids in the presence of cyclic or linear polyphosphates, pH range 7–11, yielded up to 40% of dipeptide but only 0.3‐0.5% of tripeptide [1] [2]. By addition of imidazole the yield of tripeptide could be increased about ten times [2]. Therefore, we have studied for the condensation reaction of glycine the influence of the addition to aqueous solutions 0.1 M in glycine and 0.1 M in trimetaphosphate at room temperature, pH range 6.7–8.9, of several azoles (pyrrole, pyrazole, imidazole, 1,2,4‐triazole and tetrazole), of adenine, guanine, uracil, cytosine, and of several nucleosides (adenosine, guanosine, uridine and cytidine). Among the products studied, only 1,2,4‐triazole and imidazole improve appreciably, by a factor of about 15, the yield of triglycine (up to 7.8%). While it is very likely that imidazole has played an important role during prebiotic chemical evolution, it is not clear at present whether 1,2,4‐triazole has a prebiotic significance.
A Short Synthesis of 3‐Methyl‐5‐(2,3,6‐trimethylphenyl)‐1‐penten‐3‐ol, a Sesquiterpene Isolated from Laurencia Nidifica
Authors: Oppolzer Wolfgang , Briner Paul H. , Snowden Roger L.
Published: December 2004

The racemic sesquiterpenoid alcohol 7 was synthesized in four steps (27% overall yield) from the cyclohexadienone 1. The key steps are the regioselective addition of the pentadienyllithium 2 to 1 and the Lewis‐acid induced aromatization 4 → 6.
Heterotricyclodecane. XXVI. 2,6‐Dioxatricyclo [3.3.2.03,7]decan, ein neuartiges isomers von 2,6‐dioxaadamantan
Authors: Buchs Peter , Ganter Camille
Published: December 2004

2,6‐Dioxatricyclo [3.3.2.03,7]decane, a Novel Isomer of 2,6‐Dioxaadamantane

Restriction among the great number of possible diheterotricyclodecanes to such with a carbocyclic 8membered ring (cyclooctane) as basic skeleton, which is crosswise bridged by two heteroatoms, and restriction to 5‐, 6‐ and 7membered heterocyclic rings results in the isomeric diheterotricyclodecanes of the following five different structural types: 2,6‐diheteroadamantane (a), 2,7‐diheteroisotwistane (b), 2,7‐diheterotwistance (c), 2,8‐diheterohomotwistbrendane (d), and 2,6‐diheterotricyclo [3.3.2.03,7]decane (e; s. Scheme 1).

Starting from a suitably C (5)o(2)‐functionalized 2,7‐dioxaisotwistane, first representatives with the hitherto unknown skeleton of type e were prepared by molecular rearrangement involving neighboring group participation: 2,6‐dioxatricyclo [3.3.2.03,7]decane (41) and the derivatives 34–40 thereof (Scheme 7).
Xylostosidine: The First of a New Class of Monoterpene Alkaloid Glycosides from Lonicera XylosteumL
Authors: Chaudhuri Ratan K. , Sticher Otto , Winkler Tammo
Published: December 2004

The structure of xylostosidine (1), a novel sulfur‐containing monoterpene alkaloid glucoside, is presented.
Directional Preferences of Approach of Nucleophiles to Sulfonium Ions
Authors: Britton Doyle , Dunitz Jack D.
Published: December 2004

An analysis of the crystal environments of sulfonium ions shows that short nonbonded contacts (secondary bonds) to sulfur tend to occur along the extensions of the C‐S primary bonds. Non‐bonded contacts to the C (a)‐atoms of sulfonium ions are not especially short and do not show any striking directional preference, except in sulfonium ions derived from methionine where a specific intramolecular interaction between a carboxyl O‐atom and the C (γ)‐atom may represent an incipient stage of the internal nucleophilic displacement leading to formation of homoserine and mercaptan.
High Performance Liquid Chromatography (HPLC.) of Natural Products. III [1]. Isolation of New Tripeptides from the Fermentation Broth of P. Chrysogenum
Authors: Neuss N. , Miller R. D. , Affolder C. A. , Nakatsukasa W. , Mabe J. , Huckstep L. L. , De Higuera N. La , Hunt A. H. , Occolowitz J. L. , Gilliam J. H.
Published: December 2004

α‐Aminoadipoyl‐alanyl‐valine, α‐aminoadipoyl‐serinyl‐valine and α‐aminoadipoyl‐serinyl‐isodehydrovaline have been isolated from the fermentation broth of P. chrysogenum. The configuration of α‐aminoadipoyl‐serinyl‐valine has been shown to be L, L, D.
Synthesis of [Sar1, Val5, (4′‐Azido‐3′,5′‐ditritio)Phe8] Angiotensin II, a Photoaffinity Label for the Isolation of Angiotensin II Receptors Communication 1
Authors: Bernier Michel , Escher Emannuel
Published: December 2004

The synthesis of [Sar1, Val5, (4′‐azido‐3′,5′‐ditritio)Phe8] angiotensin II from a iodinated precursor peptide is described. The principal problems of this synthesis and their resolution are discussed: (i) The β‐induced autophotolysis of the highly tritiated (73 Ci/mmol) and photosensitive label, and (ii) the absorption problems encountered during the purification of microgramm quantities. Such photoaffinity labels are being used for specific labeling and isolation of peptide hormone receptors.
Oxcarbazepine in painful diabetic neuropathy: a randomized, placebo‐controlled study
Authors: Dogra Sunil , Beydoun Said , Mazzola Jennifer , Hopwood Margaret , Wan Ying
Published: December 2004

In this multicentre, placebo‐controlled, 16‐week trial, the efficacy and safety of oxcarbazepine monotherapy in patients with neuropathic pain of diabetic origin was evaluated. Eligible patients had a 6‐month to 5‐year history of neuropathic pain symptoms of diabetic origin and a pain rating of ≥50 units on the visual analogue scale (VAS). Oxcarbazepine was initiated at a dose of 300 mg/day and titrated to a maximum dose of 1800 mg/day. In total, 146 patients (oxcarbazepine, n = 69; placebo, n = 77) were randomized. After 16 weeks, oxcarbazepine‐treated patients experienced a significantly larger decrease in the average change in VAS score from baseline compared with placebo (‐24.3 vs. −14.7 units, respectively; p = 0.01). The reduction from baseline in mean VAS score for oxcarbazepine‐treated patients was of a greater magnitude than placebo as early as week 2 (‐8.0 vs. −4.7; p < 0.05). A significantly greater proportion of oxcarbazepine‐treated patients experienced a >50% reduction from baseline in VAS score at the end of treatment compared with placebo (35.2% vs. 18.4%, respectively; p = 0.0156; number needed to treat = 6.0). Global assessment of therapeutic effect rating was improved in more oxcarbazepine patients than placebo patients (48% vs. 22%, respectively; p = 0.0025). Patients on oxcarbazepine were awakened less frequently due to pain than patients on placebo. Most adverse events were mild to moderate in severity, transient, and in line with the known tolerability profile of oxcarbazepine. These observations suggest that oxcarbazepine monotherapy, pending additional trials, may be efficacious and may provide clinically meaningful pain relief in patients with neuropathic pain of diabetic origin.
Mechanisms of action of second generation antipsychotic drugs in schizophrenia: insights from brain imaging studies
Authors: Abi-Dargham Anissa , Laruelle Marc
Published: December 2004

Multiple lines of evidence including recent imaging studies suggest that schizophrenia is associated with an imbalance of the dopaminergic system, entailing hyperstimulation of striatal dopamine (DA) D2receptors and understimulation of cortical DA D1receptors. This DA endophenotype presumably emerges from the background of a more general synaptic dysconnectivity, involving alterations inN-methyl-d-aspartate (NMDA) and glutamatergic (GLU) functions. Equally important is the fact that this DA dysregulation might further impair NMDA transmission. The first generation antipsychotic (FGA) drugs are characterized by high affinity to and generally high occupancy of D2receptors. The efficacy of FGAs is limited by a high incidence of extrapyramidal side-effects (EPS). Second generation antipsychotic (SGA) drugs display reduced EPS liability and modest but clinically significant enhanced therapeutic efficacy. Compared to FGAs, the improved therapeutic action of SGAs probably derives from a more moderate D2receptor blockade. We will review the effects of SGAs on other neurotransmitter systems and conclude by highlighting the importance of therapeutic strategies aimed at directly increasing prefrontal DA, D1receptor transmission or NMDA transmission to enhance the therapeutic effect of moderate D2receptor antagonism.
Molecular, isotopic and in situ analytical approaches to the study of meteoritic organic material
Authors: Watson Jonathan S. , Pearson Victoria K. , Sephton Mark A. , Gilmour Iain
Published: December 2004

Organic materials isolated from carbonaceous meteorites provide us with a record of pre-biotic chemistry in the early Solar System. Molecular, isotopic and in situ studies of these materials suggest that a number of extraterrestrial environments have contributed to the inventory of organic matter in the early Solar System including interstellar space, the Solar nebula and meteorite parent bodies.

There are several difficulties that have to be overcome in the study of the organic constituents of meteorites. Contamination by terrestrial biogenic organic matter is an ever-present concern and a wide variety of contaminant molecules have been isolated and identified including essential plant oils, derived from either biological sources or common cleaning products, and aliphatic hydrocarbons, most probably derived from petroleum-derived pollutants. Only 25% of the organic matter in carbonaceous chondrites is amenable to extraction with organic solvents; the remainder is present as a complex macromolecular aromatic network that has required the development of analytical approaches that can yield structural and isotopic information on this highly complex material.

Stable isotopic studies have been of paramount importance in understanding the origins of meteoritic organic matter and have provided evidence for the incorporation of interstellar molecules within meteoritic material. Extending isotopic studies to the molecular level is yielding new insights into both the sources of meteoritic organic matter and the processes that have modified it.

Organic matter in meteorites is intimately associated with silicate minerals and the in situ examination of the relationships between organic and inorganic components is crucial to our understanding of the role of asteroidal processes in the modification of organic matter and, in particular, the role of water as both a solvent and a reactant on meteorite parent bodies.
The Special Issue on Astrobiology in the UK
Authors: Burchell M.J. , Edwards H.G.M.
Published: December 2004

This issue of the International Journal of Astrobiology is devoted to papers from the astrobiology community in the United Kingdom. Twelve papers are presented in this issue, on topics ranging from pure science to science education. The call for papers was organised through the Astrobiology Society of Britain.
The effect of nutrient enrichment on growth, photosynthesis and hydraulic conductance of dwarf mangroves in Panamá
Authors: Lovelock C. E. , Feller I. C. , Mckee K. L. , Engelbrecht B. M. J. , Ball M. C.
Published: December 2004

Dwarf stands of the mangrove Rhizophora mangle L. are extensive in the Caribbean. We fertilized dwarf trees in Almirante Bay, Bocas del Toro Province, north‐eastern Panamá with nitrogen (N) and phosphorus (P) to determine (1) if growth limitations are due to nutrient deficiency; and (2) what morphological and/or physiological factors underlie nutrient limitations to growth.

Shoot growth was 10‐fold when fertilized with P and twofold with N fertilization, indicating that stunted growth of these mangroves is partially due to nutrient deficiency.

Growth enhancements caused by N or P enrichment could not be attributed to increases in photosynthesis on a leaf area basis, although photosynthetic nutrient‐use efficiency was improved. The most dramatic effect was on stem hydraulic conductance, which was increased sixfold by P and 2·5‐fold with N enrichment. Fertilization with P enhanced leaf and stem P concentrations and reduced C : N ratio, but did not alter leaf damage by herbivores.

Our findings indicate that addition of N and P significantly alter tree growth and internal nutrient dynamics of mangroves at Bocas del Toro, but also that the magnitude, pattern and mechanisms of change will be differentially affected by each nutrient.
Prescribing antibiotics in odontology and stomatology. Recommendations by the French Health Products Safety Agency
Authors:   French Health Products Safety Agency (Afssaps)
Published: December 2004

In order to limit the onset of adverse effects and the increasing emergence of bacterial resistance, the prescription of antibiotics must be reserved strictly for situations where their efficacy has been demonstrated. The French Health Products Safety Agency (Afssaps) has updated recommendations concerning the use of antibiotic treatment in odontology and stomatology. The general strategy for the prescription of antibiotics proposed by the present recommendations relies on a professional consensus. The full‐length, discussed and referenced text is available at the web site of Afssaps (http://www.afssaps.sante.fr) in the ‘Documentation et publications’ rubric.
Undocumented drug utilization and drug waste increase costs of pediatric anesthesia care
Authors: Nava‐Ocampo Alejandro A. , Alarcón‐Almanza Juan M. , Moyao‐García Diana , Ramírez‐Mora Juan Carlos , Salmerón Jorge
Published: December 2004

The present study was performed in order to identify the cost of drugs used without documenting them in the patients’ file and the wastage of drugs in a pediatric anesthesiology ward. In a prospective, blinded, observational design, drug utilization of 610 consecutive patients, undergoing an elective or emergency surgical procedure was evaluated. The number of undocumented drugs per 100 requested units and the number of wasted drugs per 100 requested units were computed and multiplied by its corresponding unitary cost. The median undocumented cost was US$92.4 (95% CI $17.2–$216.6) per 100 requested units. Succinylcholine (40 mg/2 mL) was the main undocumented drug; its use was not documented in approximately 50% cases in which this neuromuscular blocking agent was requested. However, rocuronium and nalbuphine had the highest unjustified cost, $770.6 and $847.0 per 100 requested units, respectively. Ketorolac, diclofenac, metamizol, furosemide, methylprednisolone, sodium bicarbonate, and cisatracurium were requested and documented. The median cost of wasted drug was $141.8 (95% CI $55.8–$448.2) per 100 requested drugs. More than 80% of adrenaline, naloxone, flunitrazepam, ephedrine, and cisatracurium were wasted. However, the highest cost of wasted drugs was for ondansetron, cisatracurium, methylprednisolone, and rocuronium. The uncontrolled availability and use of drugs may represent an important amount of resources wasted without any awareness of the staff in a department of pediatric anesthesia.
Carboxy‐terminal region of the yeast heat shock factor contains two domains that make transcription independent of the TFIIH protein kinase
Authors: Sakurai Hiroshi , Hashikawa Naoya , Imazu Hiromi , Fukasawa Toshio
Published: December 2004

Background:  Phosphorylation of the carboxy‐terminal domain (CTD) of the largest subunit of RNA polymerase II is implicated in transition from initiation to elongation in the transcription cycle. In yeast cells, Kin28, a subunit of the general transcription factor TFIIH, is responsible for the CTD phosphorylation. Although Kin28 is indispensable for transcription of many genes, its requirement is bypassed in certain genes such as SSA4 or CUP1, whose transcription is activated by the heat shock factor Hsf1.

Results:  We show that C‐terminal region of Hsf1, which consists of an activation domain AR2 and a regulatory domain CTM, mediates the Kin28‐independent transcription. The AR2 domain, when fused to the DNA‐binding domain of Gal4 and recruited to the GAL7 gene via the Gal4‐binding sequence, is sufficient for activating GAL7 in the absence of Kin28. We have further found that AR2 has an ability to recruit TATA box‐binding protein‐associated factors (TAFs) to the promoter. Consistently, transcription from promoters occupied naturally or artificially with TAFs is sustained in the absence of Kin28 function.

Conclusions:  These results show that CTM modulates activation function of AR2 in the Hsf1 molecule. We also suggest that recruitment of TAFs to a promoter is involved in the Kin28‐independent transcription.
Recovery and re‐establishment of Atlantic salmon, Salmo salar, in limed Norwegian rivers
Authors: Hesthagen T. , Larsen B. M.
Published: December 2004

A total of 21 acidified Norwegian rivers are now being limed to re‐establish or restore Atlantic salmon, Salmo salar L., stocks. Natural reproduction of Atlantic salmon was evident 1 year after the first year of liming in all rivers that had lost their native stocks (n = 9) except for one river. The density of fry (age 0+) developed significantly more rapidly in rivers that supported remnant stocks than in rivers that had lost their stocks, based on data 5 years after treatment. Nine of the study rivers were supplied with hatchery‐reared salmon, mainly unfed fry. Of the rivers with lost stocks, those which were supplied with fish had significantly higher densities than those that were not enhanced. On the other hand, rivers with remnant stocks that were supplied with fish had significantly lower densities of salmon fry than those that did not undergo such mitigation measures. In 2001, all limed rivers yielded 41.9 t of salmon.
Stocking of sea trout,Salmo trutta, in Lake Veere, south‐west Netherlands
Authors: Raat A. J. P.
Published: December 2004

Lake Veere (1750–2050 ha), a brackish water lake in south‐west Netherlands, is a former branch of the Oosterschelde. The lake was closed off by the construction of two dams in 1961. Since the early 1970s Lake Veere has been regularly stocked for recreational and commercial fisheries with rainbow trout,Oncorhynchus mykiss(Walbaum), brown trout,Salmo truttaL., and glass eel,Anguilla anguilla(L.). Between May and September 1996 an experimental stocking of 18 054 trout of sea trout parentage (15–16 cm; 776 kg) was carried out to study their potential for recreational fisheries. The growth and mortality of the stocked trout were estimated from recaptures in eel fyke nets. The production and consumption of the stocked trout were estimated with a bioenergetics model. After 3.5 years (May 1996–November 1999) the stocked trout measured between 50 and 70 cm. The estimated annual total mortality was 84%. During the winter of 1996–1997, the biomass of the stocked trout reached a maximum of about 1800 kg. By November 1999 the biomass was estimated to be 100 kg. The maximum daily consumption by the trout population was 60 g ha−1in October 1996 and in June 1997. The total consumption of the stocked trout population over the 3.5‐year period was estimated as 54 244 kg. The analysis suggested that the stocked trout used about 0.2% of the average annual primary production of the lake system. Although the growth and initial production of the population are attractive from the perspective of a recreational fishery, the high mortality and infestation with the salmon louse,Lepeophtheirus salmonis(Krøyer), are serious drawbacks for a future stocking programme with trout in Lake Veere.
Impact of the timing of stocking on growth and allometric index in aquaculture‐based fisheries
Authors: Ibáñez A. L.
Published: December 2004

The impact of tilapia stocking on fisheries production in Lake Metztitlán was determined through progression analysis of modes obtained from (Gaussian) kernel density estimators (KDEs) of size frequency distributions of juvenile tilapia stocked after a period of total desiccation. The relationship between the allometric index of four cohorts and water temperature and variation in the volume of the basin was analysed. The use of KDEs was found to be a useful technique for the recognition and progression analysis of modes. The reasons for the low yields from the tilapia fishery of Lake Metztitlán are poor growth rate, low water temperature, which is manifest in low allometric indices, and the use of small mesh size nets. Yields can be sustained by improving fishery management; otherwise it is necessary to continue stocking.
Variation in larval fish communities: implications for management and sampling designs in reservoir systems
Authors: Quist M. C. , Pember K. R. , Guy C. S. , Stephen J. L.
Published: December 2004

Understanding spatial and temporal patterns in larval fish distributions is important for investigating factors related to recruitment variability and for developing sampling methodologies. Variation in species diversity (Shannon index) and density (number 100 m−3) of larval fishes from nearshore and pelagic habitats in Glen Elder Reservoir, KS, USA, was assessed during 1999 and 2000. Species diversity and densities of individual taxa were significantly higher (P < 0.05) in nearshore habitats than pelagic habitats during both years. Larval fish densities were generally higher in the year 1999 with higher spring water levels. Gizzard shad Dorosoma cepedianum (Lesueur) was the most abundant taxon in nearshore and pelagic habitats during both years. In addition, larval gizzard shad was sampled for the longest duration in the upper water column and overlapped with all taxa collected. High densities of gizzard shad in both habitats suggested that the potential for competitive interactions was high, especially given the lack of aquatic vegetation and habitat heterogeneity in littoral habitats. Most of the variation in larval fish diversity and density was because of temporal variation. If sampling effort must be limited and the purpose of sampling is to monitor larval diversity or density, attention should focus on sampling the same location over long time periods rather than across a variety of sampling locations.
Assessment of year class strength in freshwater recreational fish populations
Authors: Cowx I. G. , Frear P. A.
Published: December 2004

A method for determining relative year class strength (YCS) in unexploited freshwater fish populations from individual surveys, based on reconstruction of the mortality schedule of the target population, is described. The method was tested against traditional approaches of assessment of YCS and the limitations and applicability discussed. The method is useful for analysing the factors regulating YCS in freshwater fisheries.
Forage and migration habitat of loggerhead (Caretta caretta) and olive ridley (Lepidochelys olivacea) sea turtles in the central North Pacific Ocean
Authors: Polovina Jeffrey J. , Balazs George H. , Howell Evan A. , Parker Denise M. , Seki Michael P. , Dutton Peter H.
Published: December 2004

Satellite telemetry from 26 loggerhead (Caretta caretta) and 10 olive ridley (Lepidochelys olivacea) sea turtles captured and released from pelagic longline fishing gear provided information on the turtles’ position and movement in the central North Pacific. These data together with environmental data from satellite remote sensing are used to describe the oceanic habitat used by these turtles. The results indicate that loggerheads travel westward, move seasonally north and south primarily through the region 28–40°N, and occupy sea surface temperatures (SST) of 15–25°C. Their dive depth distribution indicated that they spend 40% of their time at the surface and 90% of their time at depths <40 m. Loggerheads are found in association with fronts, eddies, and geostrophic currents. Specifically, the Transition Zone Chlorophyll Front (TZCF) and the southern edge of the Kuroshio Extension Current (KEC) appear to be important forage and migration habitats for loggerheads. In contrast, olive ridleys were found primarily south of loggerhead habitat in the region 8–31°N latitude, occupying warmer water with SSTs of 23–28°C. They have a deeper dive pattern than loggerheads, spending only 20% of their time at the surface and 60% shallower than 40 m. However, the three olive ridleys identified from genetics to be of western Pacific origin spent some time associated with major ocean currents, specifically the southern edge of the KEC, the North Equatorial Current (NEC), and the Equatorial Counter Current (ECC). These habitats were not used by any olive ridleys of eastern Pacific origin suggesting that olive ridleys from different populations may occupy different oceanic habitats.
An evaluation of the potential influence of SST and currents on the oceanic migration of juvenile and immature chum salmon (Oncorhynchus keta) by a simulation model
Authors: Azumaya Tomonori , Ishida Yukimasa
Published: December 2004

Using a salmon migration model based on the assumption that swimming orientation is temperature dependent, we investigated the determining factors of the migration of juvenile and immature chum salmon (Oncorhynchus keta) in the North Pacific. We compared the predictions of the model with catch data of immature and juvenile chum salmon collected by Japanese research vessels from 1972 to 1999. The salmon migration model reproduced the observed distributions of immature chum salmon and indicates that passive transport by wind‐driven and geostrophic currents plays an important role in the eastward migration of Asian salmon. These factors result in a non‐symmetric distribution of Asian and North American chum salmon in the open ocean. The directional swimming component contributes to the northward migration in summer. The model results indicate that during the first winter Asian chum salmon swim northward against the southward wind‐driven currents to stay in the western North Pacific. This suggests that Asian chum salmon require more energy to migrate than other stocks during the first winter of their ocean life.
Greenland cod (Gadus morhua): modeling recruitment variation during the second half of the 20th century
Authors: Stein M. , Borovkov V.A.
Published: December 2004

Two approaches were used to qualify observed variability in Greenland cod (Gadus morhua) recruitment. In the first analysis, we used the linear trend of the Greenland cod recruitment time series and climatic variables, such as air temperatures from the Denmark Strait and wind conditions off East Greenland and Southwest Greenland, to explain the interannual variation in cod recruitment off Greenland. The model resulting from this ‘trend/environmental approach’, explained 79% of the interannual variation in cod recruitment off Greenland. In the second, analytical approach, the ‘regime approach’, multiple linear regression models were used, with the input data being the time series of cod recruitment and spawning stock biomass (SSB) from Iceland and Greenland, sea surface and air temperatures around Greenland, and zonal wind components between Iceland and Greenland. Model results indicated that, during the decades between 1950 and 1990, there were three different cause–effect regimes which significantly influenced the variability of cod recruitment. The three regimes included: (a) the 1950s and 1960s, a regime with favorable sea surface temperatures and a self‐sustaining cod stock off Greenland with high SSB that produced a series of above‐average, strong year classes; (b) the 1970s and 1980s, a regime of declining SSB and recruitment, with recruitment dependent on advection from Iceland; and (c) the 1990s, when the advective potential for recruitment from the Icelandic cod stock was the only available source for replenishment of the Greenland cod stocks, because cod recruitment in Greenland waters was negligible. The three models explained 76–77% of the observed interannual variation in cod recruitment off Greenland. Both approaches suggested that advective factors were the dominant influences for cod recruitment in the ‘Iceland–Greenland System’.
Flow rate and vertical position influence ingestion rates of colonial zebra mussels (Dreissena polymorpha)
Authors: Tuchman Nancy C. , Burks Romi L. , Call Christopher A. , Smarrelli John
Published: December 2004

1. Zebra mussels aggregate to form dense colonies where, depending on the flow rate, individuals in different vertical locations within the colony may experience restricted food availability.

2. Using 32P‐labelled Chlamydomonas angulosa, we found ingestion rates of individual mussels located at the surface to exceed those in the bottom of a 6 cm thick colony by up to 75%.

3. Higher velocities (10 and 20 cm s−1) increased algal delivery to the colony's middle layer (2–4 cm depth), subsequently increasing ingestion rates to equal those in the surface layer, while increasing ingestion only for the smallest mussels in the bottom (4–6 cm).

4. At all vertical locations within the colonies, smaller mussels showed higher ingestion rates per unit mass than larger mussels, particularly at higher flow rates.
Effects of light and microcrustacean prey on growth and investment in carnivory in Utricularia vulgaris
Authors: Englund Göran , Harms Sabine
Published: December 2004

SUMMARY 1. In a 5‐week enclosure experiment, we studied the effects of light (ambient light, low light) and prey availability (no prey, prey added) on growth and investment in carnivory in Utricularia vulgaris.

2. Investment in carnivory, measured as the proportion of biomass allocated to bladders, was strongly affected by our manipulations of light intensity and prey density. In the treatment with high prey density the light reduction decreased the investment in bladders from 25% to zero. The effect of prey density on investment in bladders was negative. Because prey addition increased the concentration of nutrients, especially phosphorus, we propose that the effect of the prey treatment on investment reflected altered nutrient concentrations.

3. Availability of prey increased growth and apical biomass of Utricularia. As Utricularia had very few bladders in some treatments we suggest that the effect was due to a combination of live prey trapped and increased nutrient availability from dead prey.

4. Abundance of periphyton on Utricularia and on the enclosure walls was highest in the treatments with high prey density where nutrient concentrations were highest. Thus we interpret the response of periphyton as primarily reflecting nutrient availability.
A mass‐balance model for phosphorus in lakes accounting for biouptake and retention in biota
Authors: Håkanson Lars , Ostapenia Alexander P. , Boulion Viktor V.
Published: December 2004

SUMMARY 1. A new mass‐balance model was developed to predict phosphorus fluxes to, within and from lakes and lake concentrations of phosphorus.

2. The model is driven by data easily accessed from standard monitoring programmes or maps, so it should be useful in many contexts of lake management.

3. The phosphorus model gives seasonal (weekly) variations and accounts for all fundamental abiotic/biotic interactions and feedbacks for lakes in general for phosphorus. The model has been developed within the framework of a more comprehensive ecosystem model, LakeWeb, which accounts for production values and biomasses of nine functional groups of organisms (phytoplankton, bacterioplankton, herbivorous and predatory zooplankton, prey and predatory fish, zoobenthos, macrophytes and benthic algae).

4. The LakeWeb‐model has been critically tested in a wide limnological domain and shown to predict very well. By using this model, it is possible for the first time to predict realistic values of biouptake and retention of phosphorous in biota in lakes on a weekly basis.
Response of the flora and macroinvertebrate fauna of a chalk stream site to changes in management
Authors: Wright J. F. , Clarke R. T. , Gunn R. J. M. , Winder J. M. , Kneebone N. T. , Davy‐Bowker J.
Published: December 2004

1. Temporal changes in a series of habitats and their macroinvertebrate assemblages were examined on a 50‐m section of a chalk stream in Berkshire, England between June 1975–79 and June 1997–2001.

2. The site was part of a trout fishery in 1975–79, when river management included instream weed cutting together with control of bankside trees and riparian vegetation. Management ceased in the 1980s and by 1997–2001, the site was heavily shaded by trees and riparian vegetation.

3. The mean area of instream macrophytes decreased by 50% between the first and second sampling period. In contrast, gravel and silt increased and invading marginal vegetation formed a new habitat.

4. Changes in macroinvertebrate family richness between sampling periods were scale dependant. Although there were, on average, significantly more families in individual replicates in 1975–79 than in 1997–2001, total family richness for the site in each year did not differ significantly between sampling periods.

5. Sixty families of macroinvertebrates were recorded during the study, 50 in both sampling periods, 53 in 1975–79 and 57 in 1997–2001. This small increase in site family richness may be due to the invading marginal plants.

6. Total macroinvertebrate abundance was significantly lower in the second sampling period. A major drought in 1976 resulted in significantly higher densities of macroinvertebrates, partly through the exploitation of epiphytic diatoms by chironomid larvae. A drought in 1997 failed to elicit a similar response because of the limited macrophytes and diatoms under heavy shading by trees and marginal vegetation.

7. Significant increases in important shredders and decreases in some scrapers between the early and later sampling years largely reflected changes in available food resources.

8. Whereas macroinvertebrate family richness has been conserved under the recent ‘no management’ regime, the site is now less attractive as a fishery because of poor access and lower densities of some macroinvertebrates taken by brown trout.
Relationships between locomotor performance, microhabitat use and antipredator behaviour in lacertid lizards
Authors: Vanhooydonck B. , Van Damme R.
Published: December 2004

Microhabitat use and antipredator behaviour (i.e. behavioural response to a bird model and refuge microhabitat) was measured in an experimental set‐up for 11 lacertid lizard species. Additionally, locomotor performance (sprint speed, climbing and clambering speed, manoeuvrability and endurance) of the same species was quantified.

The results showed considerable interspecific variation in microhabitat use, behavioural response and choice of refuge microhabitat. Part of that variation could be linked to differences in locomotor capacity.

Species that frequently made use of open microhabitats tended to be fast sprinters, but had limited endurance. The behavioural data suggest these species will not start running before the predator is close at hand, and thus having high sprint capacities might be more beneficial than great endurance.

Species that spent most of their time on vertical elements appeared to be fast climbers. As such microhabitats tend to be quite exposed, lizards living there are conspicuous to predators and being able to escape fast seems relevant.

Contrary to our expectations, species mostly observed in the vegetated microhabitats did not excel in clambering capacity or manoeuvrability. Possibly, dense vegetation constitutes a safe harbour and species may no longer be under selection for locomotor speed.

Behavioural response when confronted with an aerial predator was context‐dependent in most species: most lizards fled more when in open or vertical microhabitats than when in densely vegetated ones. Moreover, when fleeing most species sought refuge in the vegetation. These findings support our idea that vegetated patches may constitute a safe harbour for lacertids.
Energetics and water economy of common spiny miceAcomys cahirinusfrom north‐ and south‐facing slopes of a Mediterranean valley
Authors: Scantlebury M. , Shanas U. , Speakman J. R. , Kupshtein H. , Afik D. , Haim A.
Published: December 2004

A comparison was made of the daily energy expenditure (DEE), resting metabolic rate (RMR) and water turnover (WTO) of two populations of Common Spiny MiceAcomys cahirinusfrom north‐ and south‐facing slopes (NFS and SFS) of the same valley, which represented ‘Mediterranean’ and ‘desert’ habitats, respectively.

An examination was made as to whether these physiological characteristics differed between mice that had been in the laboratory (outdoor conditions) for 2 months compared with mice captured from the field.

Mice from the field had greater RMR values than mice in the laboratory and NFS mice had greater RMR values than SFS mice. In the field, NFS individuals had greater DEE values than SFS individuals. Mass‐specific RMR values of SFS mice were 20% less than the allometrically predicted value, whereas those of NFS were not. WTO and sustained metabolic scope (DEE/RMR) were lower in the field than in the laboratory.

The results indicate that physiological capabilities are phenotypically plastic, as differences exist between the field and laboratory and between NFS and SFS mice. Furthermore, they highlight the importance of using field studies for understanding the link between energetics and physiological adjustment to environmental conditions.
High dosage Rhp51 suppression of the MMS sensitivity of DNA structure checkpoint mutants reveals a relationship between Crb2 and Rhp51
Authors: Smeets Monique F.M.A. , Francesconi Stefania , Baldacci Giuseppe
Published: December 2004

Background: In eukaryotic cells DNA structure checkpoints organize the cellular responses of DNA repair and transient cell cycle arrest and thereby ensure genomic stability. To investigate the exact role of crb2+ in the DNA damage checkpoint response, a genetic screen was carried out in order to identify suppressors of the conditional MMS sensitivity of a crb2‐1 mutant. Here we report the isolation of rhp51+ as a multicopy suppressor.

Results: We show that suppression is not specific for the checkpoint mutant while it is specific for the MMS treatment. Rescue by rhp51+ over‐expression is not a consequence of increased recombination repair or checkpoint compensation and epistasis analysis confirms that crb2+ and rhp51+ function in different pathways. A tight linkage between the two pathways is nevertheless suggested by the complementary expression or modification of Crb2 and Rhp51 proteins. Crb2 protein stability is down‐regulated when Rhp51 is over‐expressed and up‐regulated in the absence of Rhp51. The up‐regulation of Crb2 is independent of the activation of DNA structure checkpoints. Conversely Rhp51 is more readily activated and differentially modified in the absence of Crb2 or other checkpoint proteins.

Conclusions: We conclude that fission yeast Crb2 and Rhp51 function in two parallel, tightly connected and coordinately regulated pathways.
Nucleocytoplasmic shuttling and phosphorylation of BMAL1 are regulated by circadian clock in cultured fibroblasts
Authors: Tamaru Teruya , Isojima Yasushi , Van Der Horst Gijsbertus T. J. , Takei Kohtaro , Nagai Katsuya , Takamatsu Ken
Published: December 2004

Background:  Recent discoveries of clock proteins have unveiled an important part of the mammalian circadian clock mechanism. However, the molecular clockwork that cause these fundamental feedback loops to stably oscillate with a ∼24 h‐periodicity remain unclear.

Results:  Serum‐shocked fibroblasts were used as a cellular clock model. Circadian changes in the subcellular localization and phosphorylation of BMAL1 protein in these cells were assessed by immunocytochemistry and immunoblotting. A significant time lag between Bmal1 transcription and the cytoplasmic/nuclear accumulation of BMAL1 was observed. After its nuclear accumulation, BMAL1 accumulated in the cytoplasm again, mainly by nucleoexport, before the increase of Bmal1 transcripts. Nuclear accumulation of BMAL1 matched nuclear accumulation of CLOCK and the peak of Per1 transcription. Nuclear BMAL1 was gradually phosphorylated and then dephosphorylated in a temporally regulated manner, although cytoplasmic BMAL1 was not. In serum‐shocked mCry1/mCry2 (CRY)‐deficient fibroblasts, which lack a functional clock, both the cytoplasmic and nuclear BMAL1 were only present as hyperphosphorylated forms and their circadian nucleocytoplasmic shuttling was absent.

Conclusions:  We propose that the nucleocytoplasmic shuttling and phosphorylation states of BMAL1 are regulated by circadian clock, and that this temporally regulated and time‐delayed nuclear entry of BMAL1 is important in the maintenance of a stably oscillating clock.
Adaptive subtraction of multiples using the L1‐norm
Authors: Guitton A. , Verschuur D. J.
Published: December 2004

A strategy for multiple removal consists of estimating a model of the multiples and then adaptively subtracting this model from the data by estimating shaping filters. A possible and efficient way of computing these filters is by minimizing the difference or misfit between the input data and the filtered multiples in a least‐squares sense. Therefore, the signal is assumed to have minimum energy and to be orthogonal to the noise. Some problems arise when these conditions are not met. For instance, for strong primaries with weak multiples, we might fit the multiple model to the signal (primaries) and not to the noise (multiples). Consequently, when the signal does not exhibit minimum energy, we propose using the L1‐norm, as opposed to the L2‐norm, for the filter estimation step. This choice comes from the well‐known fact that the L1‐norm is robust to ‘large’ amplitude differences when measuring data misfit. The L1‐norm is approximated by a hybrid L1/L2‐norm minimized with an iteratively reweighted least‐squares (IRLS) method. The hybrid norm is obtained by applying a simple weight to the data residual. This technique is an excellent approximation to the L1‐norm. We illustrate our method with synthetic and field data where internal multiples are attenuated. We show that the L1‐norm leads to much improved attenuation of the multiples when the minimum energy assumption is violated. In particular, the multiple model is fitted to the multiples in the data only, while preserving the primaries.
Reassessing the impact of North Atlantic Oscillation on the sub‐Saharan vegetation productivity
Authors: WANG GUILING
Published: December 2004

The Northern Atlantic Oscillation (NAO) has been shown to have a significant impact on the terrestrial ecosystem in the Sahelian region of Africa during the 1980s, and it has been strongly suggested that NAO may be a reliable predictor for the response of the Sahelian ecosystem to global climate variability. Using data from an extended period, we provide a reassessment for the impact of NAO on the Sahelian climate and ecosystem, and show that there is no consistent relationship between NAO and the ecosystem over Sahel. Statistical analysis on the NAO, vegetation, and precipitation data indicates that NAO influences the Sahelian vegetation productivity exclusively through its impact on precipitation. However, the relationship between the NAO index and Sahelian precipitation varies substantially with time. The correlation coefficient fluctuates between positive and negative values, and does not pass the 5% significance test during most of the twentieth century. The NAO system, although documented to govern the ecosystem dynamics over many other regions, does not have a consistent impact on the ecosystem over the Sahel. Therefore, the NAO index cannot produce a useful prediction on the ecosystem variability and changes in this region. This study provides an example that correlations based on short climate and ecological records (less than 20 years in this case) can be spurious and potentially misleading.