bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theoretical and experimental studies on the Raman spectra of electrosynthesized polynaphthalene
Authors: Zhang Jiaxin , Liu Chen , Shi Gaoquan , Zhao Yufen 
Published: December 2004

AbstractPolynaphthalene (Pnap) was electrosynthesized through the direct oxidation of naphthalene in boron trifluoride diethyl etherate and was characterized with IR and Raman spectroscopy, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectroscopy, and thermogravimetric analysis. Raman spectra of oligonaphthalene were calculated with Gaussian 98 at the B3LYP/6‐31G* level. Combining the computational and experimental results, we assigned the Raman bands of pristine Pnap. The Raman bands related to the chain‐stretching vibrations of Pnap around 1600 cm−1 shifted to higher wave numbers as the polymerization degree increased. This phenomenon was in contrast to that of other conducting polymers bearing simple aromatic rings, such as polythiophene and polyfuran. The reason was that the condensed ring of Pnap and the steric repulsion of the interring hydrogen atoms prevented the elongation of conjugation sequences with the polymer chain length. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 241–251, 2005
Impact of congenital heart disease on cerebrovascular blood flow dynamics in the fetus
Authors: Kaltman J. R. , Di H. , Tian Z. , Rychik J. 
Published: December 2004

AbstractObjectivesNeurological abnormalities are present in some children after repair of congenital heart disease (CHD). Recently, structural brain abnormalities have been identified in infants prior to cardiac surgery. By altering in utero blood flow patterns, the type of CHD may impact upon cerebrovascular flow dynamics prior to birth. We sought to determine whether left‐ and right‐sided obstructive congenital heart lesions modify cerebrovascular flow dynamics in the fetus.MethodsPulsed Doppler was used to measure blood flow velocities in the umbilical (UA) and middle cerebral (MCA) arteries in 172 fetuses from 20 to 39 weeks' gestational age referred for fetal echocardiography. Pulsatility index (PI), an indicator of downstream vascular resistance, was determined by (peak systolic velocity—end‐diastolic velocity)/mean velocity.ResultsFetuses with hypoplastic left heart syndrome (HLHS; n = 28) had decreased MCA‐PI (P = 0.009) compared to normal fetuses (n = 114). Fetuses with right‐sided obstructive lesions (RSOL; n = 17) had increased MCA‐PI (P = 0.001) when compared to fetuses with HLHS. The UA‐PI was elevated in fetuses with RSOLs (P = 0.045).ConclusionsCerebrovascular resistance is lower than normal in fetuses with HLHS, a condition in which cerebral perfusion occurs retrograde via the ductus arteriosus. Fetuses with RSOL had significantly higher cerebrovascular resistance compared to fetuses with HLHS. The type of CHD impacts upon fetal cerebrovascular blood flow distribution and this may have implications for later development of neurological sequelae. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.
Differential diagnosis in fetuses with absent septum pellucidum
Authors: Malinger G. , Lev D. , Kidron D. , Heredia F. , Hershkovitz R. , Lerman‐Sagie T. 
Published: December 2004

AbstractObjectiveTo elucidate the characteristic morphological features that may help in the prenatal differential diagnosis of absent septum pellucidum as demonstrated by ultrasound.MethodsTwenty‐six fetuses were referred to the fetal neurology clinic due to mild to severe ventriculomegaly and a connection between the lateral ventricles. The following ultrasonographic features were evaluated: place and extent of the ventricular communication, non‐cleavage of the hemispheres and deep gray nuclei, callosal anomalies, position of the choroid plexus, and other central nervous system and facial or body anomalies. A flowchart was created in order to facilitate the final diagnosis.ResultsThe presence of non‐cleavage and/or characteristic facial anomalies prompted the diagnosis of holoprosencephaly (HPE) in 14 fetuses, including two fetuses with the middle interhemispheric variant. Ten fetuses were diagnosed as having hydrocephalus based on the lack of the same features and the observation that the communication between the lateral ventricles was at the level of the third ventricle with almost normal anterior and posterior segments. In two fetuses the diagnosis of septo‐optic dysplasia vs. isolated agenesis of the cavum septi pellucidi was contemplated.ConclusionsThe use of the proposed flowchart enabled differentiation between hydrocephalus and HPE. The communication between the ventricles in hydrocephalic fetuses may be due to a disruption of the septum pellucidum or to a pathological enlargement of the foramen of Monro. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.
Electoral Reforms, Membership Stability and the Existence of Committee Property Rights in American State Legislatures
Authors: SQUIRE PEVERILL , HAMM KEITH E. , HEDLUND RONALD D. , MONCRIEF GARY F. 
Published: December 2004

One of the most creative theories advanced about legislative organization in recent years is Katz and Sala's linkage of the development of committee property rights in the US House of Representatives to the introduction of the Australian ballot. Katz and Sala argue that the Australian ballot – a government-printed ballot cast in secret that replaced a party-produced ballot that was cast in public – gave members of the House an incentive to pursue personal constituency votes. This, in turn, led to the rise of committee property rights as members sought to keep their committee assignments from term to term because of the potential electoral benefits they derived from them. In this Note we use the state legislative committee membership dataset collected by Hamm and Hedlund and their colleagues to test whether committee property rights appeared in American state legislatures at roughly the same time as Katz and Sala find they emerged in the US House. State legislatures were, of course, exposed to the same electoral innovation at the same time. But, while in some ways state legislatures were much like Congress as organizations, in other ways they were very different. Our cross-sectional data and the variance in important institutional variables they provide allow us to test a critical proposition about the importance of membership stability rates in mediating the rise of committee property rights. We also go beyond Katz and Sala's analysis by testing to see if differences in Australian ballot design (office column and party bloc) across the states influenced the behaviour of legislators in the way their theory suggests.
Seasonal variation in photosynthetic capacity of montane conifers
Authors: NIPPERT J. B. , DUURSMA R. A. , MARSHALL J. D. 
Published: December 2004

SummaryThe capacity to perform photosynthesis, given appropriate environmental conditions, is reflected by measurements of the maximum quantum yield of photosystem II (Fv/Fm). The seasonal course ofFv/Fmmay help define the length of the annual photosynthetic period in temperate evergreen forests.Fv/Fmwas measured 31 times from September to May on six conifer species located along an altitudinal gradient between 400 and 1400 m a.s.l. in northern Idaho, USA. The species were Western Redcedar (Thuja plicataDonn ex D. Donn), Douglas Fir (Pseudotsuga menziesii(Beissn.) Franco), Engelmann Spruce (Picea engelmanniiParry), Grand Fir (Abies grandis(Dougl.) Lindl.), Ponderosa Pine (Pinus ponderosaLaws.) and Lodgepole Pine (Pinus contortaDougl.).Species differed in meanFv/Fm, in magnitude of response to maximum and minimum temperature, and in altitude effects other than temperature. For two speciesFv/Fmin spring differed from that in autumn, even when measured at the same air temperature. Regardless of temperature, most species maintained some photosynthetic capacity all winter.A lag of several days to 2 months was observed in the response ofFv/Fmto ambient temperature. The lag differed among species. It was not observed in Grand Fir, and was as long as 2 months in Western Redcedar. Over all species combined the best overall correlation was with a moving average of maximum temperature over the previous 30 days.The correlation betweenFv/Fmand maximum temperature was generally stronger than that with minimum temperature (average root mean‐squared error was reduced by 10%), presumably because maximum temperatures better reflect daytime photoinhibitory conditions.A reduced model predictedFv/Fmbased on species and maximum temperature; this model can be used to parameterize models describing the annual cycle of photosynthetic capacity for the six conifer species included in this study.
Murray's law and the hydraulicvsmechanical functioning of wood
Authors: McCULLOH K. A. , SPERRY J. S. , ADLER F. R. 
Published: December 2004

SummaryMurray's law states that the hydraulic conductance per blood volume of the cardiovascular system is maximized when the sum of the vessel radii cubed (Σ r3) is conserved.We hypothesize that Murray's law will apply to xylem conduits as long as they only transport water and do not also help support the plant. Specifically, the less volume of wood occupied by conduits, the more the conduits should conform to Murray's law.We tested the applicability of Murray's law along a continuum of decreasing conduit fraction from coniferous (91% conduits) to diffuse‐porous (24% conduits) to ring‐porous wood (12% conduits), using anatomical and functional tests. The anatomical test compared the Σ r3conservation across branch points by direct measurements of conduit radii. The functional test compared the hydraulic conductivity between branches of different ages.As predicted, Murray's law was rejected in conifer wood where hydraulic function is coupled to mechanical support. The angiosperm wood did not deviate as strongly from Murray's law, especially the ring‐porous type. For comparison we report previously published results from compound leaves and vines which showed general agreement with Murray's law.Deviation from Murray's law was associated with fewer, narrower conduits distally causing a decrease in Σ r3distally. Although less efficient hydraulically, this configuration is not top‐heavy and is more mechanically stable. With the evolution of vessels and fibres, angiosperm wood can more closely approach Murray's law while still meeting mechanical requirements.
Linking the foraging performance of a marine predator to local prey abundance
Authors: GRÉMILLET D. , KUNTZ G. , DELBART F. , MELLET M. , KATO A. , ROBIN J.‐P. , CHAILLON P.‐E. , GENDNER J.‐P. , LORENTSEN S.‐H. , MAHO Y. LE 
Published: December 2004

Summary

Knowledge of the functional response of predators to prey densities conditions our understanding of food webs. Such links are still poorly understood within the higher trophic levels of marine ecosystems.
We present the first field study recording the foraging effort and foraging yield of a seabird (the Great Cormorant, Phalacrocorax carbo) as well as the abundance and quality of prey within its foraging area.
We confirm that Great Cormorants foraging off West‐Greenland show the highest foraging performance recorded for a marine predator (between 17 and 41 g fish caught per minute underwater). Former work suggests that such high foraging yield should be based upon the exploitation of extremely profitable prey patches.
Contrary to this hypothesis, average prey abundances estimated within the foraging areas of the cormorants were low (0·03–0·09 prey m−2, depending on methods), as was the average calorific value of the prey items (4·2 kJ g−1).
Our study suggests that Great Cormorants remain highly successful predators even when exploiting modest prey resources. These findings have implications for our understanding of predator–prey relationships, and for the management of Great Cormorant populations.
Starvation resistance in Drosophila melanogaster: testing for a possible ‘cannibalism’ bias
Authors: HUEY R. B. , SUESS J. , HAMILTON H. , GILCHRIST G. W. 
Published: December 2004

Summary

Starvation resistance is often measured in physiological studies with Drosophila and other insects. One common method involves measuring time until death of groups of insects. This method assumes that survivors are not obtaining nutrition from their vial mates that die early. However, because some Drosophila larvae can scavenge carcasses, this group protocol might inadvertently lead to a ‘cannibalism’ bias.
We evaluated whether starvation resistance of Drosophila melanogaster was increased if fly carcasses were available from the beginning of the experiment. We used a mixed‐model anova to assess the direct and interactive effects of isofemale line, sex and immediate access to carcasses.
Males survived starvation longer than females, despite the smaller size of males. Isofemale lines differed significantly in resistance. Immediate access to fly carcasses had no impact on resistance.
These results suggest that starving adult flies do not gain measurable benefits from access to carcasses. Consequently, this experiment seemingly validates a widely used method of measuring starvation resistance.
HPLC sugar analysis reveals the nutritional state and the feeding history of parasitoids
Authors: STEPPUHN A. , WÄCKERS F. L. 
Published: December 2004

Summary

Adult parasitoids depend on sugar‐rich foods such as nectar and honeydew to meet their energy requirements. Many laboratory studies have established fitness benefits of sugar feeding for parasitoids.
Nevertheless, we know little about the nutritional ecology of parasitoids in the field, chiefly because of the limited specificity of methods applicable for field studies.
Here we use high‐performance liquid chromatography (HPLC) analysis to study the sugar profile of Cotesia glomerata L. and Microplitis mediator Haliday relative to feeding‐treatment. We identify the overall sugar level and the ratio of glucose to fructose as two parameters that in combination unambiguously characterize an individual's nutritional state and feeding history.
Unfed parasitoids contained low total sugar levels and glucose levels that typically exceeded fructose levels more than five‐fold. Parasitoids with constant access to sucrose had high overall sugar levels with a balanced glucose–fructose ratio.
The marked shift of the glucose–fructose ratio after feeding was still evident in C. glomerata individuals whose total sugar content had decreased to unfed levels after 3 days of starvation. This makes it possible to distinguish between unfed individuals and those that did feed several days ago.
In addition to revealing past feeding events, HPLC analysis also enables the identification and quantification of a wide spectrum of sugars present in each specimen. When food sources contain specific sugars this can provide additional information about the type of sugar source consumed.
HPLC analyses revealed that trehalose, considered to be the ‘insect haemolymph sugar’, is not present in the two species investigated here.
Overall, HPLC sugar analysis provides a powerful tool to investigate energy status, feeding history and nutritional physiology of field‐collected parasitoids.
Inflorescence architecture and wind pollination in six grass species
Authors: FRIEDMAN JANNICE , HARDER LAWRENCE D. 
Published: December 2004

Summary

Inflorescence architecture and floral morphology vary extensively within the Poaceae, but the functional significance of this variation remains largely unknown. As grasses are wind‐pollinated, their inflorescence diversity probably reflects alternate solutions to manipulating airstreams to enhance pollen export and import. We tested this hypothesis with two field experiments that contrasted pollen removal and receipt by compact and diffuse inflorescences.
In the ‘aggregation’ experiment, we tied together panicle branches of two species with diffuse inflorescences, creating more compact inflorescences. Aggregation reduced pollen removal from both species, probably by increasing boundary‐layer thickness. The effects of inflorescence aggregation differed between the two species in a manner that is consistent with pollen‐size differences, which could affect the ability of pollen grains to pass through the thickened boundary layer around stigmas.
The ‘staking’ experiment constrained inflorescence motion and revealed that culm characteristics contribute to the interaction between grass inflorescences and airstreams. In particular, inflorescence oscillation principally serves pollen removal for species with compact inflorescences, but is of primary importance in pollen receipt for species with diffuse architectures.
These results suggest that inflorescence architecture interacts with wind in a complex manner to facilitate pollination and supports the hypothesis that the extensive diversity of inflorescence architecture within the Poaceae represents evolutionary solutions to the physical constraints of wind pollination.
Limited ability of Palestine SunbirdsNectarinia oseato cope with pyridine alkaloids in nectar of Tree TobaccoNicotiana glauca
Authors: TADMOR‐MELAMED H. , MARKMAN S. , ARIELI A. , DISTL M. , WINK M. , IZHAKI I. 
Published: December 2004

SummarySecondary compounds are common in floral nectar but their relative effects on nectar consumption and utilization in nectarivorous birds are unclear.We studied the effect of two pyridine alkaloids, nicotine and anabasine, present in Tree Tobacco (Nicotiana glauca) nectar, on food consumption, gut transit time and sugar assimilation efficiency of the Palestine Sunbird (Nectarinia osea), a pollinator ofN. glaucain east Mediterranean ecosystems.Sunbirds demonstrated dose‐dependent deterrence; they were not deterred by the lowest natural concentrations of these alkaloids in nectar (0·1 ppm nicotine and 0·6 ppm anabasine) but they were significantly deterred by the average concentrations detected in nectar (0·5 ppm nicotine and 5 ppm anabasine).The two pyridine alkaloids reduced gut transit time (by 30–42%) and sugar assimilation efficiency (by 9–17%) compared with the control alkaloid‐free diet.Sunbirds are able to cope with low, but not average, concentrations of nicotine and anabasine inN. glaucanectar. If sunbirds are efficient pollinators ofN. glaucathey may induce selection on it to reduce pyridine alkaloid production in the nectar. Alternatively, high concentrations in someN. glaucaplants may lead the birds to visit more plants with lower alkaloid concentrations. Hence, they will be more efficient pollinators, especially if other nectar‐producing plants are scarce.
Response of host species to brood parasitism in dung beetles: importance of nest location by parasitic species
Authors: GONZÁLEZ‐MEGÍAS A. , SÁNCHEZ‐PIÑERO F. 
Published: December 2004

SummaryBrood parasitism is an interaction that negatively affects reproductive success of host species, some of which have evolved defences to reduce offspring mortality caused by the parasites. In this study, we analyse the responses to interspecific brood parasitism of a dung beetle species,Onthophagus merdarius, in which reproductive success is heavily affected by parasitic beetles.We used a combination of field and laboratory experiments to approach this question. Manipulating the effect of the presence of brood parasites on host nesting showed that there were no differences between treatments in nest traits. This absence of responses of the host species might be related to how and when brood parasites localize host nests: brood parasites actively find host nests after the nests have been finished and the nest burrows sealed.Although both the rate of parasitism and the mortality rate caused by parasites are very high onO. merdarius, the possibility of the host species to evolve defence strategies against brood parasites is probably constrained by resource limitation for nesting in the study area. Because brood parasitism and resource limitation act synergistically favouring small brood size and small brood‐mass size, smaller individuals may be also favoured under these conditions in the study area.
Pharmacodynamics and pharmacokinetics of nonsteroidal anti‐inflammatory drugs in species of veterinary interest
Authors: LEES P. , LANDONI M. F. , Giraudel J. , TOUTAIN P. L. 
Published: December 2004

This review summarises selected aspects of the pharmacokinetics (PK) and pharmacodynamics (PD) of nonsteroidal anti‐inflammatory drugs (NSAIDs). It isnotintended to be comprehensive, in that it covers neither minor species nor several important aspects of NSAID PD. The limited objective of the review is to summarise those aspects of NSAID PK and PD, which are important to an understanding of PK–PD integration and PK–PD modelling (the subject of the next review in this issue). The general features of NSAID PK are: usually good bioavailability from oral, intramuscular and subcutaneous administration routes (but with delayed absorption in horses and ruminants after oral dosing), a high degree of binding to plasma protein, low volumes of distribution, limited excretion of administered dose as parent drug in urine, marked inter‐species differences in clearance and elimination half‐life and ready penetration into and slow clearance from acute inflammatory exudate.The therapeutic effects of NSAIDs are exerted both locally (at peripheral inflammatory sites) and centrally. There is widespread acceptance that the principal mechanism of action (both PD and toxicodynamics) of NSAIDs at the molecular level comprises inhibition of cyclooxygenase (COX), an enzyme in the arachidonic acid cascade, which generates inflammatory mediators of the prostaglandin group. However, NSAIDs possess also many other actions at the molecular level. Two isoforms of COX have been identified. Inhibition of COX‐1 is likely to account for most of the side‐effects of NSAIDs (gastrointestinal irritation, renotoxicity and inhibition of blood clotting) but a minor contribution also to some of the therapeutic effects (analgesic and anti‐inflammatory actions) cannot be excluded. Inhibition of COX‐2 accounts for most and possibly all of the therapeutic effects of NSAIDs. Consequently, there has been an intensive search to identify and develop drugs with selectivity for inhibition of COX‐2. Whole bloodin vitroassays are used to investigate quantitatively the three key PD parameters (efficacy, potency and sensitivity) for NSAID inhibition of COX isoforms, providing data on COX‐1:COX‐2 inhibition ratios. Limited published data point to species differences in NSAID‐induced COX inhibition, for both potency and potency ratios. Members of the 2‐arylpropionate sub‐groups of NSAIDs exist in two enantiomeric forms [R‐(−) andS‐(+)] and are licensed as racemic mixtures. For these drugs there are marked enantiomeric differences in PK and PD properties of individual drugs in a given species, as well as important species differences in both PK and PD properties.
Endogenous Lipogenic Regulators of Spore Balance in
Aspergillus nidulans
Authors: Tsitsigiannis Dimitrios I. , Kowieski Terri M. , Zarnowski Robert , Keller Nancy P. 
Published: December 2004

ABSTRACT

The ability of fungi to produce both meiospores and mitospores has provided adaptive advantages in survival and dispersal of these organisms. Here we provide evidence of an endogenous mechanism that balances meiospore and mitospore production in the model filamentous fungus
Aspergillus nidulans
. We have discovered a putative dioxygenase, PpoC, that functions in association with a previously characterized dioxygenase, PpoA, to integrate fatty acid derived oxylipin and spore production. In contrast to PpoA, deletion of
ppoC
significantly increased meiospore production and decreased mitospore development. Examination of the PpoA and PpoC mutants indicate that this ratio control is associated with two apparent feedback loops. The first loop shows
ppoC
and
ppoA
expression is dependent upon, and regulates the expression of,
nsdD
and
brlA
, genes encoding transcription factors required for meiospore or mitospore production, respectively. The second loop suggests Ppo oxylipin products antagonistically signal the generation of Ppo substrates. These data support a case for a fungal “oxylipin signature-profile” indicative of relative sexual and asexual spore differentiation.