bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interplay between the energetics of foraging and thermoregulatory costs in the green‐backed firecrown hummingbird Sephanoides sephaniodes
Authors: Fernández Maria José , López‐Calleja M. Victoria , Bozinovic Francisco 
Published: October 2002

AbstractIn response to the interplay between variation in food quality and energetic demands, the foraging behaviour of captive green‐backed firecrown hummingbirds Sephanoides sephaniodes was studied. Hummingbirds were exposed to two temperatures (25°C vs 15°C), two food qualities (0.5 vs 0.75 m sucrose solutions), and two costs of feeding (birds were provided with feeders with and without a perch). Food selection and consumption were measured, as well as time budgets and metabolic rate while feeding. We predicted that when given a choice, birds would minimize the cost of feeding by selecting feeders with a perch and with a high sugar concentration. However, rather than increasing energy consumption when energy availability was low and thermoregulatory demands were high, hummingbirds remained perched. They reduced feeding and spent most of their time perching. Our results identify a novel behavioural and physiological strategy in hummingbirds. These birds seem to shift their foraging behaviour depending on thermoregulatory and feeding costs. When these costs are high, rather than matching them with increased energy consumption, hummingbirds reduce energy costs by reducing activity. They seemed to adopt the following strategy: when food quality was high and thermoregulatory demands were low, they adopted a high‐expense lifestyle. In contrast, when thermoregulatory costs were high, they adopted an energy conserving strategy even when food quality was high. We hypothesize that limitations imposed by physiological processes may explain why animals do not forage during all available time and why under some circumstances they choose foraging behaviours with lower rates of net energy gain.
Diving behaviour of two Australian bimodally respiring turtles, Rheodytes leukops and Emydura macquarii, in a natural setting
Authors: Gordos Matthew , Franklin Craig E. 
Published: October 2002

AbstractTime‐depth recorders were used to investigate the diving performance and behaviour of two bimodally respiring turtle species, Rheodytes leukops and Emydura macquarii, known to have a high and low reliance on aquatic respiration, respectively. Significant differences in diving performance between R. leukops and E. macquarii were observed in the number of dives/day (39.3±5.38 vs 112.2±11.73 dives/day; mean±se), mean dive length (33.1±7.33 min vs 9.6±2.26 min) and maximum dive length (623±104.74 min vs 67.1±8.14 min), respectively. Differences in diving performance between R. leukops and E. macquarii are attributed to the species' reliance (or lack thereof) upon aquatic respiration. Rheodytes leukops displayed a weak bimodal pattern of increased surfacing frequency in the early morning (05:00–07:00) and late afternoon (14:00–18:00), while E. macquarii displayed a strong bimodal pattern of elevated surfacing frequency over similar time periods. Daily patterns of increased surfacing frequency for both species failed to correlate with fluctuating aquatic Po2 levels or water temperature, and may instead be explained by the heightened activity levels of both species during twilight.
Energy cost of ectoparasitism: the fleaXenopsylla ramesison the desert gerbilGerbillus dasyurus
Authors: Khokhlova I. S. , Krasnov B. R. , Kam M. , Burdelova N. I. , Degen A. A. 
Published: October 2002

AbstractMetabolizable energy intake and changes in body mass was measured in the desert gerbilGerbillus dasyuruswhen parasitized by the fleaXenopsylla ramesis. We hypothesized that energy requirements for maintenance, or average daily metabolic rate, of parasitized gerbils would be higher than those of non‐parasitized gerbils. We also hypothesized that the efficiency of utilization of energy for maintenance would be the same for parasitized and non‐parasitized gerbils, as this measurement is dependent mainly on dietary quality. Fifty fleas feeding on a gerbil consumed 3.68±1.19 mg blood, in total. This amounted to 34.3±1.8% of body mass of a starving flea and only about 0.17% of the blood volume of the host. The absolute amount of blood consumed byX. ramesisis the lowest reported for fleas in other studies. This suggested that the pressure of parasitism ofX. ramesisonG. dasyurusin terms of blood consumed was relatively low. Both our hypotheses were confirmed. Average daily metabolic rate of the parasitized gerbils (7.75 kJ g−0.54d−1) was 16% higher than that of non‐parasitized gerbils (6.69 kJ g−0.54d−1). In addition, at zero metabolizable energy intake, the parasitized gerbils lost body mass at a faster rate than the non‐parasitized gerbils (4.34vs3.95% body mass d−1). The efficiency of utilization of energy in the parasitized and non‐parasitized gerbils was similar.
Intrinsic and extrinsic sources of variation in size at birth and rates of postnatal growth in the big brown bat Eptesicus fuscus (Chiroptera: Vespertilionidae)
Authors: Hood Wendy R. , Bloss Johanna , Kunz Thomas H. 
Published: October 2002

AbstractWe examined the relationship between intrinsic and extrinsic variables and variation in size at birth and rates of postnatal growth in the big brown bat Eptesicus fuscus at maternity roosts in central Massachusetts and southern New Hampshire. Body mass and length of forearm at birth were lowest when precipitation in the month preceding births was relatively high. In addition, body mass at birth was significantly lower when ambient temperatures during late pregnancy were relatively low. Pups born to middle age mothers were heavier than pups born to young or old mothers. When evaluated using mark–recapture data (longitudinal method), postnatal growth in length of forearm and body mass was greater for pups born to middle age and older mothers and change in body mass was greater for female pups than for male pups. When growth data were evaluated using the trajectory method, the rate of growth for length of forearm was greatest when ambient temperature was highest. Age prediction equations were improved when maternal age was incorporated into predictive equations. We recommend considering both intrinsic and extrinsic variables in studies where maternal effort is evaluated and age prediction equations are used for estimating postnatal growth rates in free‐ranging bats.
Cranial variability in the Eastern hedgehog Erinaceus concolor (Mammalia: Insectivora)
Authors: Krystufek B. 
Published: October 2002

AbstractCranial variability was studied in 307 Eastern hedgehogs Erinaceus concolor Martin, 1838 from central and south‐eastern Europe, the Near East, Middle East, and the Caucasus. The maxillary bone always contacted the nasal bone in European samples, forming a naso‐maxillary suture which was mainly long (>2 mm). In contrast, the suture was usually short (<1–2 mm) in hedgehogs from the Near East and Middle East, and sometimes the maxillary failed to reach the nasal bone. In the latter case, the premaxillary formed a suture with the frontal bone (length = 2.5 mm in extreme cases). Two morphotypes could be distinguished on this basis: the roumanicus morphotype (with a long suture) and the concolor morphotype (with the naso‐maxillary suture short or absent). Discriminant function analysis of nine geographic samples, and based on 14 linear log‐transformed skull measurements, revealed two clusters: one included four European samples of the roumanicus morphotype and the other contained three Asiatic samples of the concolor morphotype. Specimens of the roumanicus morphotype from Asia were classified as having either the concolor or roumanicus morphotype; however, on average their skull morphology suggested closer affinities with the former.
GLUING OF ABELIAN CATEGORIES AND DIFFERENTIAL OPERATORS ON THE BASIC AFFINE SPACE
Authors: Bezrukavnikov Roman , Braverman Alexander , Positselskii Leonid 
Published: October 2002

The notion of gluing of abelian categories was introduced in a paper by Kazhdan and Laumon in 1988 and studied further
by Polishchuk. We observe that this notion is a particular case of a general categorical construction.We then apply this general notion to the study of the ring of global differential operators $\mathcal{D}$ on the basic affine
space $G/U$ (here $G$ is a semi-simple simply connected algebraic group over $\mathbb{C}$ and $U\subset G$ is a maximal
unipotent subgroup).We show that the category of $\mathcal{D}$-modules is glued from $|W|$ copies of the category of $D$-modules on $G/U$ where
$W$ is the Weyl group, and the Fourier transform is used to define the gluing data. As an application we prove that the
algebra $\mathcal{D}$ is Noetherian, and get some information on its homological properties.AMS 2000 Mathematics subject classification: Primary 13N10; 16S32; 17B10; 18C20
Microwave‐enhanced enzyme reaction for protein mapping by mass spectrometry: A new approach to protein digestion in minutes
Authors: Pramanik Birendra N. , Mirza Urooj A. , Ing Yao Hain , Liu Yan‐Hui , Bartner Peter L. , Weber Patricia C. , Bose Ajay K. 
Published: October 2002

AbstractAccelerated proteolytic cleavage of proteins under controlled microwave irradiation has been achieved. Selective peptide fragmentation by endoproteases trypsin or lysine C led to smaller peptides that were analyzed by matrix‐assisted laser desorption ionization (MALDI) or liquid chromatography‐electrospray ionization (LC‐ESI) techniques. The efficacy of this technique for protein mapping was demonstrated by the mass spectral analyses of the peptide fragmentation of several biologically active proteins, including cytochrome c, ubiquitin, lysozyme, myoglobin, and interferon α‐2b. Most important, using this novel approach digestion of proteins occurs in minutes, in contrast to the hours required by conventional methods.
Structural and nucleotide‐binding properties of YajQ and YnaF, two Escherichia coli proteins of unknown function
Authors: Saveanu Cosmin , Miron Simona , Borza Tudor , Craescu Constantin T. , Labesse Gilles , Gagyi Cristina , Popescu Aurel , Schaeffer Francis , Namane Abdelkader , Laurent‐Winter Christine , Bârzu Octavian , Gilles Anne‐Marie 
Published: October 2002

AbstractStructural genomics is a new approach in functional assignment of proteins identified via whole‐genome sequencing programs. Its rationale is that nonhomologous proteins performing similar or related biological functions might have similar tertiary structure. We used dye pseudoaffinity chromatography, two‐dimensional gel electrophoresis, and mass spectrometry to identify two novel Escherichia coli nucleotide‐binding proteins, YnaF and YajQ. YnaF exhibited significant sequence identity with MJ0577, an ATP‐binding protein from a hyperthermophile (Methanococcus jannaschii), and with UspA, a protein from Haemophilus influenzae that belongs to the Universal Stress Protein family. YnaF conserves the ATP‐binding site and the dimeric structure observed in the crystal of MJ0577. The protein YajQ, present in many bacterial genomes, is missing in eukaryotes. In the absence of significant similarities of YajQ to any solved structure, we determined its structural and ligand‐binding properties by NMR and isothermal titration calorimetry. We demonstrate that YajQ is composed of two domains, each centered on a β‐sheet, that are connected by two helical segments. NMR studies, corroborated with local sequence conservation among YajQ homologs in various bacteria, indicate that one of the β‐sheets is mostly involved in biological activity.
Molecular dynamics of the FixJ receiver domain: movement of the β4–α4 loop correlates with the in and out flip of Phe101
Authors: Roche Philippe , Mouawad Liliane , Perahia David , Samama Jean‐Pierre , Kahn Daniel 
Published: October 2002

AbstractFixJ is a two‐domain response regulator involved in nitrogen fixation in Sinorhizobium meliloti. Recent X‐ray characterization of both the native (unphosphorylated) and the active (phosphorylated) states of the protein identify conformational changes of the β4–α4 loop and the conserved residue Phe101 as the key switches in activation. These structures also allowed investigation of the transition between conformations of this two‐component regulatory receiver domain by molecular dynamics simulations. The path for the conformational change was studied with a distance constraint directing the system from one state to the other. The simulations provide evidence for a correlation between the conformation of the β4–α4 loop and the orientation of the residue Phe101. A model presenting the sequence of events during the activation/deactivation process is discussed.
ABSOLUTE CONTINUITY IN PERIODIC WAVEGUIDES
Authors: SOBOLEV ALEXANDER V. , WALTHOE JONATHAN 
Published: October 2002

We study second order elliptic operators with periodic coefficients in two-dimensional simply connected periodic waveguides with the Dirichlet or Neumann boundary conditions. It is proved that under some mild smoothness restrictions on the coefficients, such operators have purely absolutely continuous spectra. The proof follows a method suggested previously by A. Morame to tackle periodic operators with variable coefficients in dimension 2.2000 Mathematical Subject Classification: 35J10, 35P05, 35J25.
VINOGRADOV'S INTEGRAL AND BOUNDS FOR THE RIEMANN ZETA FUNCTION
Authors: FORD KEVIN 
Published: October 2002

The main result is an upper bound for the Riemann zeta function in the critical strip: $\zeta(\sigma + it) \le A|t|^{B(1 - \sigma)^{3/2}} \log^{2/3} |t|$ with $A = 76.2$ and $B = 4.45$, valid for $\frac12 \le \sigma \le 1$ and $|t| \ge 3$. The previous best constant $B$ was 18.5. Tools include a variant of the Korobov–Vinogradov method of bounding exponential sums, an explicit version of T. D. Wooley's bounds for Vinogradov's integral, and explicit bounds for mean values of exponential sums over numbers without small prime factors, also using methods of Wooley. An auxiliary result is the exponential sum bound $S(N, t) \le 9.463 N^{1 - 1/(133.66\lambda^2)}$, where $N$ is a positive integer, $t$ is a real number, $\lambda = (\log t)/(\log N)$ and$S(N,t) = \max_{0 < u \le 1} \max_{N < R \le 2N} \left| \sum_{N < n \le R} (n + u)^{-it} \right|.$$2000 Mathematical Subject Classification: primary 11M06, 11N05, 11L15; secondary 11D72, 11M35.
Selection of Mutant Cell Lines Resistant to Infection byChlamydia trachomatisandChlamydia pneumoniae
Authors: Fudyk Trevor , Olinger Lynn , Stephens Richard S. 
Published: October 2002

ABSTRACTThe lytic outcome of natural infection byChlamydia trachomatiswas exploited to select CHO (Chinese hamster ovary) cells, following chemical mutagenesis, that were deficient in their ability to sustain productive chlamydial infection. Four distinct mutant cell phenotypes with defects in either attachment or postattachment mechanisms that are required for infection byC. trachomatisandChlamydia pneumoniaewere characterized.
SET-VALUED PSEUDOMONOTONE MAPS AND DEGENERATE EVOLUTION INCLUSIONS
Authors: KUTTLER KENNETH L. , SHILLOR MEIR 
Published: October 2002

We develop the theory of evolution inclusions for set-valued pseudomonotone maps. The problems we investigate are [Formula: see text] where B=B(t) is a linear operator that may vanish and A is a set-valued pseudomonotone operator. We prove the existence of unique solutions of such, possibly degenerate, problems.We apply the theory to the problem of dynamic frictional contact with a slip dependent friction coefficient and prove the existence of its unique weak solution.This theory opens the way for the investigation of sophisticated dynamical models in mechanics and frictional contact problems.
Assessment of the importance of individual plant-parasitic nematode species in a community dominated by Heterodera sacchari on upland rice in Côte d'Ivoire
Authors: Plowright Richard , Coyne Daniel 
Published: October 2002

AbstractIn temperate climates, densities of plant-parasitic nematodes at or shortly before sowing are a useful predictor of their damage potential. Re-examination of data from nematode communities on upland rice in Côte d'Ivoire showed that interpretation of nematode pest potentials and the damage caused by either individual species, or by the community as a whole, is less simple. The numerical proportion of individual nematode species within a plant-parasitic nematode community, comprising Heterodera sacchari, Pratylenchus zeae , Meloidogyne incognita, Helicotylenchus dihystera, Mesocriconema tescorum and Xiphinema spp., changed with duration of the cropping cycle. The relative importance to the crop of the different species changed with time, and with development of the community structure over the course of the season. Analysis suggested that for H.sacchari, the mid-season population densities were most highly correlated with crop damage (yield loss) and therefore its damage potential for that particular season. The pest potential of other known rice pest species, such as M. incognita and P.zeae, was likely indicated earlier in the season, but the population increase of other nematode species in the community, particularly H. sacchari, compounded the interpretation of the data for other species. The use of single linear regression to assess the importance of individual nematode species conflicted with results of analyses using multiple stepwise regression, while use of cluster analysis permitted the identification of species groups at early and late stages in the cropping season.
The African Carnoyidae (Nematoda: Rhigonematida). 5. Three new species of Brumptaemilius Dollfus, 1952 and remarks on B. seychellarum Adamson, 1987
Authors: Hunt David 
Published: October 2002

AbstractThree new species of the genus Brumptaemilius Dollfus, 1952 are described from the intestine of diplopods from Ghana and Ivory Coast. Brumptaemilius ultimus sp. n., from Ghana and Ivory Coast, is characterised by the huge spicules (731-894 μm long); numerous (105-136) transverse striae on the spicule shafts; the verrucose appearance of the tuberculate papillae; the blunt, peg-like spines on the posterior cloacal lip; the disposition and form of the rugosities; the very short male tail spike (0.3-0.5 times as long as the gubernaculum); lateral alae absent in both sexes and the exceptionally long female vagina. A spermatophore is apparently absent. B. verrucosus sp. n., from Ivory Coast, is characterised by relatively few tuberculate papillae with a minutely verrucose appearance; relatively long spicules (519-553 μm) with numerous (84-95) transverse striae; spicule shafts parallel and not wrapped around one another distally; gubernaculum 77-87 μm long; presence of subventral paracloacal fields of digitiform rugosities and male tail spike 0.6 (0.6-0.7) times as long as gubernaculum. In addition, the female lateral alae start in the isthmus region and terminate shortly before the anus, and a spermatophore is apparently absent, although a prominent copulatory plug was often seen occluding the vaginal lumen. Brumptaemilius ypoxystus sp. n., from Ivory Coast, is distinguished by features of the male copulatory apparatus and the area rugosa. It is characterised by having four staggered rows of subventral tuberculate papillae, each bearing a terminal corona of ca five to nine minute projections; a postcloacal field comprising transverse, imbricate rows of broad, conical spines; the form and disposition of the subventral fields of rugosities; rugose fields not extending as a ventral band anterior to the cloacal aperture; non-rugose ventral region on tail posterior to last pair of postcloacal papillae; spicules 306 (280-328) μm long with 40 (33-48) transverse striae; gubernaculum 102 (91-107) μm long; tail spike 0.5 (0.4-0.6) times as long as the gubernaculum; lateral alae absent in both sexes and presence of a spermatophore bearing a short peduncle penetrating the distal vagina. A population of B.seychellarum Adamson, 1987 is described from the Seychelles and the presence of a spermatophore recorded in the species for the first time. Useful characters for species diagnosis within the genus are briefly discussed.
Phylogenetic analysis of the phoretic association between Bursaphelenchus conicaudatus (Nematoda: Aphelenchoididae) and Psacothea hilaris (Coleoptera: Cerambycidae)
Authors: Futai Kazuyoshi , Kanzaki Natsumi 
Published: October 2002

AbstractThe phoretic relationships between the nematode Bursaphelenchus conicaudatus and the yellow-spotted longicorn beetle, Psacothea hilaris, collected at various districts in Japan were investigated. A high proportion of all ten subspecies of the beetle examined were infected with the nematodes, suggesting the universality of this phoretic association. Molecular analysis based on the partial base sequence of cytochrome oxidase subunit I in the mitochondrial DNA revealed that the phylogenetic relationships among ten subspecies of the beetle was similar to that among associated nematode isolates obtained from each beetle subspecies. Intraspecific vector replacements were supposed to occur in the isolates of B. conicaudatus on two islands. The phoretic association between the nematode and the beetle is assumed to have been established before the divergence of P.hilaris into subspecies.
Anatomical informatics: Millennial perspectives on a newer frontier
Authors: Trelease Robert B. 
Published: October 2002

AbstractOne of the most ancient of sciences, anatomy has evolved over many centuries. Its methods have progressively encompassed dissection instruments, manual illustration, stains, microscopes, cameras and photography, and digital imaging systems. Like many other more modern scientific disciplines in the late 20th century, anatomy has also benefited from the revolutionary development of digital computers and their automated information management and analytical capabilities. By using newer methods of computer and information sciences, anatomists have made outstanding contributions to science, medicine, and education. In that regard, there is a strong rationale for recognizing anatomical informatics as a proper subdiscipline of anatomy. A high‐level survey of the field reveals important anatomical applications of computer sciences methods in imaging, image processing and visualization, virtual reality, modeling and simulation, structural database processing, networking, and artificial intelligence. Within this framework, computational anatomy is a developing field focusing on data‐driven mathematical models of bodily structures. Mastering such computer sciences and informatics methods is crucial for new anatomists, who will shape the future in research, clinical knowledge, and teaching. Anat Rec (New Anat) 269:224–235, 2002. © 2002 Wiley‐Liss, Inc.
Microglia as a source and target of cytokines
Authors: Hanisch Uwe‐Karsten 
Published: October 2002

AbstractCytokines constitute a significant portion of the immuno‐ and neuromodulatory messengers that can be released by activated microglia. By virtue of potent effects on resident and invading cells, microglial cyto‐ and chemokines regulate innate defense mechanisms, help the initiation and influence the type of immune responses, participate in the recruitment of leukocytes to the CNS, and support attempts of tissue repair and recovery. Microglia can also receive cyto‐ and chemokine signals as part of auto‐ and paracrine communications with astrocytes, neurons, the endothelium, and leukocyte infiltrates. Strong responses and modulatory influences can be demonstrated, adding to the emerging view that microglial behavior is highly dependent on the (cytokine) environment and that reactions to a challenge may vary with the stimulation context. In principle, microglial activation aims at CNS protection. However, failed microglial engagement due to excessive or sustained activation could significantly contribute to acute and chronic neuropathologies. Dysregulation of microglial cytokine production could thereby promote harmful actions of the defense mechanisms, result in direct neurotoxicity, as well as disturb neural cell functions as they are sensitive to cytokine signaling. GLIA 40:140–155, 2002. © 2002 Wiley‐Liss, Inc.