bluuebunny/crossref_metadata_2025 huggingface dataset:
Some asymptotic results for exponential functionals of Brownian motion
Authors: Gruet J.-C. , Shi Z.
Published: April 2006

The study of exponential functionals of Brownian motion has recently attracted much attention, partly motivated by several problems in financial mathematics. Let be a linear Brownian motion starting from 0. Following Dufresne (1989), (1990), De Schepper and Goovaerts (1992) and De Schepper et al. (1992), we are interested in the process (for δ > 0), which stands for the discounted values of a continuous perpetuity payment. We characterize the upper class (in the sense of Paul Lévy) of X, as δ tends to zero, by an integral test. The law of the iterated logarithm is obtained as a straightforward consequence. The process exp(W(u))du is studied as well. The class of upper functions of Z is provided. An application to the lim inf behaviour of the winding clock of planar Brownian motion is presented.
Distributions and expectations of singular random variables
Authors: Campbell L. L. , McKellips A. L. , Wittke P. H.
Published: April 2006

Intersymbol and cochannel interference in a communications channel can often be modelled as the sum of an infinite series of random variables with weights which decay fairly rapidly. Frequently, this yields a random variable which is singular but non-atomic. The Hausdorff dimension of the distribution is estimated and methods for calculating expectations are studied. A connection is observed between the dimension and the complexity of the calculation of an expectation.
Spectral representations of the transition probability matrices for continuous time finite Markov chains
Authors: Peng Nan Fu
Published: April 2006

Using an easy linear-algebraic method, we obtain spectral representations, without the need for eigenvector determination, of the transition probability matrices for completely general continuous time Markov chains with finite state space. Comparing the proof presented here with that of Brown (1991), who provided a similar result for a special class of finite Markov chains, we observe that ours is more concise.
A complete convergence theorem for an epidemic model
Authors: Andjel Enrique , Schinazi Rinaldo
Published: April 2006

We use an interacting particle system on ℤ to model an epidemic. Each site of ℤ can be in either one of three states: empty, healthy or infected. An empty site x gets occupied by a healthy individual at a rate βn1(x) where n1(x) is the number of healthy nearest neighbors of x. A healthy individual at x gets infected at rate αn2(x) where n2(x) is the number of infected nearest neighbors of x. An infected individual dies at rate δ independently of everything else. We show that for all α, β and δ> 0 and all initial configurations, all the sites of a fixed finite set remain either all empty or all healthy after an almost surely finite time. Moreover, if the initial configuration has infinitely many healthy individuals then the process converges almost surely (in the sense described above) to the all healthy state. We also consider a model introduced by Durrett and Neuhauser where healthy individuals appear spontaneously at rate β > 0 and for which coexistence of 1's and 2's was proved in dimension 2 for some values of α and β. We prove that coexistence may occur in any dimension.
Buffer overflow asymptotics for a buffer handling many traffic sources
Authors: Courcoubetis Costas , Weber Richard
Published: April 2006

As a model for an ATM switch we consider the overflow frequency of a queue that is served at a constant rate and in which the arrival process is the superposition of N traffic streams. We consider an asymptotic as N → ∞ in which the service rate Nc and buffer size Nb also increase linearly in N. In this regime, the frequency of buffer overflow is approximately exp(–NI(c, b)), where I(c, b) is given by the solution to an optimization problem posed in terms of time-dependent logarithmic moment generating functions. Experimental results for Gaussian and Markov modulated fluid source models show that this asymptotic provides a better estimate of the frequency of buffer overflow than ones based on large buffer asymptotics.
A local proof of the Swiss Army formula of Palm calculus
Authors: Konstantopoulos Takis
Published: April 2006

The so-called ‘Swiss Army formula', derived by Brémaud, seems to be a general purpose relation which includes all known relations of Palm calculus for stationary stochastic systems driven by point processes. The purpose of this article is to present a short, and rather intuitive, proof of the formula. The proof is based on the Ryll–Nardzewski definition of the Palm probability as a Radon-Nikodym derivative, which, in a stationary context, is equivalent to the Mecke definition.
Laplace transforms and the renewal equation
Authors: Kebir Y.
Published: April 2006

Vinogradov (1973) used the Laplace transform to characterize the IFR class of life distributions and later Block and Savits (1980) extended the characterization to the main reliability classes. Here we use the same transform again to characterize the continuous time renewal equation and some properties of its solution.
Isolation of mesenchymal stem cells from human placenta: Comparison with human bone marrow mesenchymal stem cells
Authors: Miao Zongning , Jin Jun , Chen Lei , Zhu Jianzhong , Huang Wei , Zhao Jidong , Qian Hanguang , Zhang Xueguang
Published: April 2006

The presence within bone marrow of a population of mesenchymal stem cells (MSCs) able to differentiate into a number of different mesenchymal tissues, including bone and cartilage, was first suggested by Friedenstein nearly 40 years ago. Since then MSCs have been demonstrated in a variety of fetal and adult tissues, including bone marrow, fetal blood and liver, cord blood, amniotic fluid and, in some circumstances, in adult peripheral blood. MSCs from all of these sources can be extensively expanded in vitro and when cultured under specific permissive conditions retain their ability to differentiate into multiple lineages including bone, cartilage, fat, muscle, nerve, glial and stromal cells. There has been great interest in these cells both because of their value as a model for studying the molecular basis of differentiation and because of their therapeutic potential for tissue repair and immune modulation. However, MSCs are a rare population in these tissues. Here we tried to identify cells with MSC‐like potency in human placenta. We isolated adherent cells from trypsin‐digested term placentas and examined these cells for morphology, surface markers, and differentiation potential and found that they expressed several stem cell markers. They also showed endothelial and neurogenic differentiation potentials under appropriate conditions. We suggest that placenta‐derived cells have multilineage differentiation potential similar to MSCs in terms of morphology and cell‐surface antigen expression. The placenta may prove to be a useful source of MSCs.
Effect of ewe feeding system (grass v. concentrate) on intramuscular fatty acids of lambs raised exclusively on maternal milk
Authors: Valvo M. A. , Lanza M. , Bella M. , Fasone V. , Scerra M. , Biondi L. , Priolo A.
Published: April 2006

Twenty pregnant Comisana ewes were divided into two groups of 10. One group was allowed to graze a vetch pasture (grass). The second group of animals was housed collectively in a pen and was given hay and concentrates (concentrate). After lambing, all the ewes were allowed to stay with the respective lambs between 18:00 h and 07:00 h of the following day in two different pens. Therefore all the lambs were raised exclusively on maternal milk. The lambs were slaughtered at 38 days of age. Milk and lamb meat (longissimus dorsi muscle) fatty acids were analysed. Ewes on grass produced milk with a lower (P< 0·001) proportion of saturated fatty acids and with a higher proportion of both monounsaturated (P< 0·05) and polyunsaturated fatty acids (P< 0·01) than ewes given concentrates. Trans-vaccenic acid was significantly higher (P< 0·001) in milk from grass-fed animals compared with ewes given concentrates. Linoleic acid (C18: 2 n-6) tended to be higher (P= 0·06) in milk from ewes on concentrates while linolenic acid (C18: 3 n-3) was significantly higher (P< 0·001) in milk from animals grazing pasture. Conjugated linoleic acid (cis-9, trans-11 C18: 2) was almost double in milk from grass-fed ewes compared with animals given concentrates (P< 0·001). Regarding lamb tissue, trans-vaccenic acid (C18: 1 trans-11) was higher (P= 0·01) in the fat from lambs raised by grazing ewes. Linoleic acid (C18: 2 n-6) was at higher concentration (P< 0·001) in the fat from lambs raised by ewes given concentrates. Linolenic acid (C18: 3 n-3) was increased three-fold (P< 0·001) in the fat of lambs from the grass group compared with lambs suckled by ewes given concentrates. The isomer cis-9, trans-11 of conjugated linoleic acid was present at double concentration (P< 0·001) in the fat from animals raised by grazing ewes. Eicosapentaenoic (C20: 5 n-3; EPA) and docosaesaenoic (C22: 6 n-3; DHA) acids were higher (respectivelyP< 0·001 andP= 0·01) in the intramuscular fat from lambs from the grass group compared with animals from the concentrate group. The n-6/n-3 ratio was lower (P< 0·001) in the meat from lambs raised by grazing ewes. Overall this trial showed that ewe feeding system strongly affects intramuscular fatty acids even in lambs raised exclusively on maternal milk.
Equity and pragmatism in judgement‐making about the placement of sibling groups
Authors: Hollows Anne , Nelson Peter
Published: April 2006

This paper considers the influences on professional judgements about large sibling group placement. The paper attempts to explain how social workers’ awareness of the significance of sibling relationships operates in the process of making judgements and decisions about placement. It undertakes a detailed phenomenological analysis of the process in five cases involving large sibling groups. Drawing on philosophical theories of equity and pragmatism, it proposes a theoretical approach to addressing the issues in practice.
A pilot study to compare the use of prototypes of multipositional paediatric walking sticks and tripods with conventional sticks and tripods by children with cerebral palsy
Authors: Toms B. , Harrison B. , Bower E.
Published: April 2006

Background  The researchers (B.H. and B.T.) designed prototypes of a walking stick and a tripod termed Multipositional Paediatric Walking Aids for children with cerebral palsy (CP). The design won the ‘Jenx Award for Innovation in Paediatric Physiotherapy’. The object of this study was to ascertain whether the prototypes had any benefit over conventional designs in children with CP.

Methods  A small case series within‐subject comparison design was used. There were four periods, AABA, each 4 weeks in length. Prototypes were used during period B. Eight children with CP between 4 and 11 years were recruited, four used sticks and four used tripods. Following an orthopaedic assessment, each child had assessments at the commencement of the study and every 4 weeks thereafter: (1) Energy used while walking using Physiological Cost Index (PCI). (2) Motor abilities using (a) Gross Motor Function Measure (GMFM‐88) and (b) Gross Motor Performance Measure (GMPM). (3) Hand/forearm position recorded on a visual analogue. (4) Parent/child questionnaire.

Results  Physiological Cost Index improved overall when the prototypes were used suggesting the amount of energy used when walking with the prototypes was less than with conventional sticks/tripods. GMFM‐88 and GMPM results improved for some but not all children. Results for PCI, GMFM and GMPM were not statistically significant. The hand/forearm position of stick users consistently improved at assessment 4. Questionnaire results indicated that stick users preferred the prototypes.

Conclusion  Multipositional sticks/tripods may have benefits over conventional sticks/tripods. Children using sticks rather than tripods preferred the prototypes. The study demonstrates the need to undertake scientifically controlled trials before marketing new equipment.
Hyperandrogenism in carriers of CYP21 mutations: the role of genotype
Authors: Admoni Osnat , Israel Shosh , Lavi Idit , Gur Michal , Tenenbaum‐Rakover Yardena
Published: April 2006

Objective  It has been hypothesized that carriers of CYP21 mutations are at increased risk of developing clinically evident hyperandrogenism. In the present study, we assessed the risk for symptoms of androgen excess in carriers of CYP21 gene mutations and the effect of different mutations on phenotype.

Design  All subjects underwent clinical evaluation, ACTH stimulation testing, and molecular analysis of the CYP21 gene.

Patients  One hundred and eighty‐seven subjects were included in the study. Five groups were defined according to genotype: A, 38 patients with classical‐congenital adrenal hyperplasia (CAH); B, 16 patients with non classical CAH; C, 66 family member carriers; D, 24 children and adolescents with symptoms suggestive of hyperandrogenism who were found to be heterozygous and E, 43 subjects with androgen excess symptoms who had normal genotype.

Measurements  Cortisol and 17‐hydroxyprogesterone (17OHP) were measured basally and 60 min after ACTH stimulation. Analysis of seven common mutations of the CYP21 gene, which collectively cover 95% of the mutations in the Israeli population, was performed. The hormonal results were correlated with the genotype.

Results  The symptomatic carriers had a significantly higher rate of the mild mutation V281L compared with the family members (58% vs. 22%) and significantly higher levels of ACTH‐stimulated 17OHP (mean 37·2 and 21 nmol/l, respectively; P = 0·025). Higher values of peak 17OHP levels were found in the carriers of the V281L mutation compared with carriers of other mutations (P = 0·025). Stimulated 17OHP levels were significantly higher in carriers compared with normal genotype subjects (P < 0·0001).

Conclusions  Our findings are the first to show that there is increased risk of androgen excess in carriers of CYP21 mutations and that the risk is related to genotype. Carriers for the mild, V281L mutation, are at higher risk of symptoms of androgen excess than carriers of the severe mutations. It appears that the variable phenotypes can be at least partially attributed to the degree of impairment of enzyme activity in different mutations. The severe consequences of hyperandrogenism in some of the carrier subjects indicate the need for long‐term follow‐up in these patients.
Insulin resistance and the metabolic syndrome in obese French children
Authors: Druet Céline , Dabbas Myriam , Baltakse Véronique , Payen Catherine , Jouret Béatrice , Baud Christine , Chevenne Didier , Ricour Claude , Tauber Maïthé , Polak Michel , Alberti Corinne , Levy‐Marchal Claire
Published: April 2006

Objective  To estimate the frequency of the metabolic syndrome (MS) and of the insulin resistance syndrome (IRS) in overweight or obese French children and to determine the risk factors.

Design, patients and methods  A total of 308 overweight and obese children [166 girls, 142 boys, aged 7–17 years; median body mass index (BMI) 4·7 standard deviation (SD) (Q1–Q3: 3·9–5·8) adjusted for age and sex] were included. The frequency of the MS was assessed with the National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) criteria and the frequency of the IRS with World Health Organization (WHO) criteria.

Results  The overall frequency of MS and IRS was 15·9% and 42·5%, respectively. The most common component, after abdominal obesity (95·8%) and IR (71·8%), was elevated systolic blood pressure (28·6%). The frequency of glucose tolerance disorders was low (3·6%). The frequency of MS was independently influenced by homeostatic model assessment (HOMA) (P = 0·06) and waist‐to‐hip ratio (P = 0·09), whereas the frequency of IRS was influenced by adiposity (degree of obesity: P = 0·02; waist‐to‐hip ratio: P = 0·05), puberty (P = 0·05) and mother's BMI (P = 0·01). Ethnicity had no effect on either MS or IRS.

Conclusions  Metabolic complications and IR are frequent in overweight and obese children whereas the frequency of glucose tolerance disorders is very low. IRS is more prevalent than MS, indicating a major role of IR, which could precede the other metabolic complications in obese children. IRS is a relevant marker for the risk of type 2 diabetes (T2D) and cardiovascular complications in obese European children.
Plasma ghrelin levels of gastrectomized and vagotomized patients are not affected by glucose administration
Authors: Pekic S. , Pesko P. , Djurovic M. , Miljic D. , Doknic M. , Glodic J. , Dieguez C. , Casanueva F. F. , Popovic V.
Published: April 2006

Background  Ghrelin is a brain–gut peptide with GH‐releasing and appetite‐inducing activities, secreted mainly by the stomach. Circulating ghrelin concentrations fall rapidly after nutrient ingestion as well as after oral and intravenous glucose challenge. A number of gut hormones including ghrelin require an intact vagal system, which has been hypothesized to have a major role in initiating the postprandial fall in ghrelin levels.

Aim  We aimed to investigate the effect of oral glucose challenge on ghrelin secretion in gastrectomized (GASTRX) and vagotomized patients.

Design  Interventional study.

Patients  Six GASTRX–vagotomized patients and 11 healthy sex‐ and body mass index (BMI)‐matched subjects.

Methods  An oral glucose tolerance test (OGTT) was performed in all subjects. At baseline, circulating plasma total ghrelin, serum glucose, insulin and GH levels were measured. Serum glucose, insulin, GH and plasma ghrelin levels were determined every 30 min for 2 h.

Results  Plasma ghrelin levels at baseline were reduced by 55% in GASTRX–vagotomized patients compared to the control group (P < 0·01). In control subjects, plasma ghrelin levels decreased significantly during the OGTT whereas in GASTRX–vagotomized patients no reduction was registered (26·4 ± 2·8%vs. 5·5 ± 3·4%). The OGTT revealed a significantly greater increase in circulating glucose levels and serum insulin levels while GH response was not different in GASTRX–vagotomized patients compared to control subjects.

Conclusions  Our data show that circulating ghrelin levels in GASTRX and vagotomized patients were not suppressed after oral glucose administration, unlike control subjects, suggesting that this effect could be due, at least in part, to the lack of contribution of the vagal nervous system to the regulation of ghrelin.
Mycorrhizal mediation of plant N acquisition and residue decomposition: Impact of mineral N inputs
Authors: TU CONG , BOOKER FITZGERALD L. , WATSON DOROTHY M. , CHEN XIN , RUFTY THOMAS W. , SHI WEI , HU SHUIJIN
Published: April 2006

Mycorrhizas are ubiquitous plant–fungus mutualists in terrestrial ecosystems and play important roles in plant resource capture and nutrient cycling. Sporadic evidence suggests that anthropogenic nitrogen (N) input may impact the development and the functioning of arbuscular mycorrhizal (AM) fungi, potentially altering host plant growth and soil carbon (C) dynamics. In this study, we examined how mineral N inputs affected mycorrhizal mediation of plant N acquisition and residue decomposition in a microcosm system. Each microcosm unit was separated into HOST and TEST compartments by a replaceable mesh screen that either prevented or allowed AM fungal hyphae but not plant roots to grow into the TEST compartments. Wild oat (Avena fatua L.) was planted in the HOST compartments that had been inoculated with either a single species of AM fungus, Glomus etunicatum, or a mixture of AM fungi including G. etunicatum. Mycorrhizal contributions to plant N acquisition and residue decomposition were directly assessed by introducing a mineral 15N tracer and 13C‐rich residues of a C4 plant to the TEST compartments. Results from 15N tracer measurements showed that AM fungal hyphae directly transported N from the TEST soil to the host plant. Compared with the control with no penetration of AM fungal hyphae, AM hyphal penetration led to a 125% increase in biomass 15N of host plants and a 20% reduction in extractable inorganic N in the TEST soil. Mineral N inputs to the HOST compartments (equivalent to 5.0 g N m−2 yr−1) increased oat biomass and total root length colonized by mycorrhizal fungi by 189% and 285%, respectively, as compared with the no‐N control. Mineral N inputs to the HOST plants also reduced extractable inorganic N and particulate residue C proportion by 58% and 12%, respectively, in the corresponding TEST soils as compared to the no‐N control, by stimulating AM fungal growth and activities. The species mixture of mycorrhizal fungi was more effective in facilitating N transport and residue decomposition than the single AM species. These findings indicate that low‐level mineral N inputs may significantly enhance nutrient cycling and plant resource capture in terrestrial ecosystems via stimulation of root growth, mycorrhizal functioning, and residue decomposition. The long‐term effects of these observed alterations on soil C dynamics remain to be investigated.
Potential impacts of climate change on nitrogen transformations and greenhouse gas fluxes in forests: a soil transfer study
Authors: HART STEPHEN C.
Published: April 2006

Relatively little research has been conducted on how climate change may affect the structure and function of arid to semiarid ecosystems of the American Southwest. Along the slopes of the San Francisco Peaks of Arizona, USA, I transferred intact soil cores from a spruce‐fir to a ponderosa pine forest 730 m lower in elevation to assess the potential impacts of climate change on soil N cycling and trace gas fluxes. The low‐elevation site has a mean annual soil temperature about 2.5°C higher than the high‐elevation site. Net rates of N transformations and trace gas fluxes were measured in high‐elevation soil cores incubatedin situand soil cores transferred to the low‐elevation site. Over a 13‐month period, volumetric soil water content was similar in transferred soil cores relative to soil cores incubatedin situ. Net N mineralization and nitrification increased over 80% in transferred soil cores compared within situsoil cores. Soil transfer significantly increased net CO2efflux (120%) and net CH4consumption (90%) relative to fluxes of these gases from soil cores incubatedin situ. Soil net N2O fluxes were relatively low and were not generally altered by soil transfer. Although the soil microbial biomass as a whole decreased in transferred soil cores compared within situsoil cores after the incubation period, active bacterial biomass increased. Transferring soil cores from the low‐elevation to the high‐elevation site (i.e. simulated global cooling) commonly, but not consistently, resulted in the opposite effects on soil pools and processes. In general, soil containment (root trenching) did not significantly affect soil measurements. My results suggest that small increases in mean annual temperature can have large impacts on soil N cycling, soil–atmosphere trace gas exchanges, and soil microbial communities even in ecosystems where water availability is a major limiting resource.
Absence of post‐Miocene Red Sea land bridges: biogeographic implications
Authors: Fernandes Carlos A. , Rohling Eelco J. , Siddall Mark
Published: April 2006

In a large number of studies concerned with species movements between Africa and Eurasia, including the migrations of hominids out of Africa, a frequently‐cited dispersal route is across a hypothetical land bridge in the southern Red Sea, which is suggested to have emerged during glacial sea‐level lowstands. This paper, however, unequivocally demonstrates that palaeoceanographic and palaeoecological data are incompatible with the existence of Red Sea land bridges since the Miocene. The case is made by presenting the first quantitative history of water depth above the Red Sea sill for the last 470,000 years, a time period that includes the four most recent glacial–interglacial cycles, and by discussing the predictable consequences of any land bridge formation on the Red Sea sedimentary and microfossil records. The absence of post‐Miocene Red Sea land bridges has extensive implications for biogeographic models in the Afro‐Arabian region. Genetic, morphometric and palaeontological patterns reported in the literature cannot be related to dispersals over a land bridge, or in the case of marine organisms, separation of the Red Sea from the Indian Ocean by a land bridge. If such patterns in terrestrial species are only congruent with a southern Red Sea dispersal route, then they need to be considered in terms of sweepstake rafting, anthropogenic introduction, or in the particular case of the Out‐of‐Africa migration by modern humans, seafaring. The constraints imposed by our palaeoenvironmental record on biogeographic reconstructions within and around the Red Sea will hopefully encourage both the review of previous works and the preference for multidisciplinary approaches in future studies.
Patients’ experiences of living with oesophageal cancer
Authors: Andreassen Sissel , Randers Ingrid , Näslund Erik , Stockeld Dag , Mattiasson Anne‐Cathrine
Published: April 2006

Aims.  The aim of this study is to describe patients’ experiences of living with oesophageal cancer and how they seek information.

Background.  Oesophageal cancer is a devastating disease with poor prognosis. Nursing care for individuals with oesophageal cancer requires increased knowledge of how they experience illness and how it affects them.

Method.  Data were collected by semi‐structured, qualitative interviews with 13 participants. Content analysis was used to analyse data.

Results.  Four themes were identified: (i) Experiences of becoming a patient diagnosed with oesophageal cancer is distinguished by the participants’ experiences of vague symptoms, of receiving the diagnosis and of existential concerns evoked by the illness. (ii) Experiences of undergoing investigations and treatment consist of the participants’ experiences of extreme tiredness in relation to investigations and treatment. (iii) Experiences of intrusions in daily life is conceptualized by the participants’ experiences of how the illness influenced their daily life. (iv) Managing a life‐threatening illness consists of a variety of strategies, which the participants employed to manage their life‐threatening illness.

Conclusions.  The participants were unprepared of receiving a diagnosis of oesophageal cancer. Dysphagia, fatigue and uncertainty influenced the participants’ everyday life. To manage the illness one of their strategies was seeking for information. The physicians were considered the main source of information, but family as well as friends with medical knowledge were also acknowledged as valuable sources.

Relevance to clinical practice.  Understanding patients’ experiences of living with oesophageal cancer is important to improve nursing care. When caring for these patients, focus ought to be on the whole family. In nursing care, it is important to be aware of the effects of dysphagia and fatigue. Health‐care professionals ought to organize meetings with fellow patients and recommend literature and websites that provide patients with high quality information.
Genetic differentiation of the marbled white butterfly, Melanargia galathea, accounts for glacial distribution patterns and postglacial range expansion in southeastern Europe
Authors: SCHMITT THOMAS , HABEL JAN CHRISTIAN , ZIMMERMANN MARCO , MÜLLER PAUL
Published: April 2006

Isolation of Mediterranean species in the southern European peninsulas during the cold glacial phases often resulted in differentiation of several genetic lineages confined to the respective peninsulas. However, whilst there is good genetic evidence for multiple refugia in Iberia, there are only limited data available for the Balkans. Therefore, we wish to examine the hypothesis of a strong genetic structuring within southeastern Europe for the existence of multiple Balkan differentiation centres and/or several leading edges. As a model we use the marbled white butterfly, Melanargia galathea. We studied 18 allozyme loci of 564 individuals from 16 populations distributed over a large part of southeastern Europe. The single populations showed moderately high genetic diversity and no northward decline of genetic diversity was detected. The overall genetic differentiation between populations was considerable (FST 7.0%). Cluster analysis discriminated three genetic groups: (i) a western flank in the former Yugoslavia, parts of eastern Austria and Hungary; (ii) an eastern flank with populations from Bulgaria and Romania (south of the southern Carpathians and eastern Carpathians); and (iii) the eastern Carpathian Basin. Hierarchical variance analysis distributed 53% of the variance among populations between these three groups. One sample from the Greek–Bulgarian border clustered within the eastern flank, but showed some tendency towards the eastern Carpathian Basin populations. Two populations from Carinthia clustered together with the eastern Carpathian Basin ones and a population from Styria showed an intermediate genetic composition between the three groups. Most probably, the eastern and the western flank groups are due to postglacial range expansion from the northeastern and the northwestern edges of the glacial differentiation centre (so‐called leading edges). The eastern Carpathian Basin group may have resulted from postglacial expansion from northern Greece through valley systems of the central Balkan peninsula, maybe even expanding westwards north of the Balkan mountains reaching some parts of eastern Austria (e.g. Carinthia). Therefore, the Balkanic refugium of M. galathea may or may not have been continuous along the coastal areas of the Mediterranean, but must have been strongly genetically structured.
Microclimatic factors influencing refugium suitability for Rhodnius prolixus
Authors: HEGER THIERRY J. , GUERIN PATRICK M. , EUGSTER WERNER
Published: April 2006

Abstract Rehydration in the triatomine bug Rhodnius prolixus (Stål) is dependent on the blood meal, and water balance regulation is crucial for survival of starving bugs. In an experimental arena with zones at different climatic conditions, starved R. prolixus nymphs prefer a cooler and more humid zone, stopping there more often and for longer periods. This is probably a behavioural adaptation to limit water loss and reduce metabolic rate. In the Venezuelan State of Portuguesa, temperature and humidity were monitored in three kinds of potential refugia during the dry season: (i) in a palm roof; (ii) in a crack of the wall of a house; and (iii) in a palm tree crown. Fluctuations in temperature and saturation deficit are not very different inside and outside the palm roof except during a few hours of the day when the sun is at its zenith. In the crack of the wall, the diurnal temperature range is reduced to 6.5 °C compared with 12.4 °C outside, and the saturation deficit varies by only 7.6 hPa compared with 28.6 hPa outside. In the palm tree crown, the daily temperature range is only 4.2 °C compared with 13.8 °C outside, and the saturation deficit is permanently < 5 hPa. The microclimatic conditions in the palm tree crown would appear to be ideal for starving R. prolixus, but this kind of refugium generally harbours low densities of bugs, probably related to a combination of predation, pathogens and lower mean temperature within the crown. Such biotic and abiotic constraints play a lesser role in the less ideal palm roof and wall crack refugia where bugs can proliferate as long as hosts are readily available nearby.
Genome‐wide analysis of high‐altitude maize and gene knockdown stocks implicates chromatin remodeling proteins in response to UV‐B
Authors: Casati Paula , Stapleton Ann E. , Blum James E. , Walbot Virginia
Published: April 2006

A comparative analysis, by expression profiling of maize, was performed to identify novel components in the mechanisms of maize responses to UV‐B. Five high‐altitude landraces grown from 2000 to 3400 m naturally receive higher UV‐B fluence than plants at lower altitudes and similar latitudes. These high‐altitude landraces were compared directly with a low‐altitude line and with literature reports for other temperate maize lines. A microarray analysis demonstrated that among the UV‐B responsive transcripts, several types of gene implicated in chromatin remodeling are differentially expressed before and after UV‐B treatment in high‐altitude lines. RNAi transgenic plants with lower expression of four such chromatin‐associated genes exhibited hypersensitivity to UV‐B by measurements of leaf arching, increased leaf chlorosis and necrosis, and altered UV‐B regulation of selected genes. These results collectively suggest that genes involved in chromatin remodeling are crucial for UV‐B acclimation and that some high‐altitude lines exhibit adaptations to this challenge.
Replicated population divergence caused by localized coevolution? A test of three hypotheses in the red crossbill-lodgepole pine system
Authors: Edelaar P. , Benkman C. W.
Published: April 2006

Several lines of evidence support the hypothesis that local populations of red crossbills (Loxia curvirostra complex) enter into a predator-prey arms race with lodgepole pine (Pinus contorta latifolia) in the absence of competing pine squirrels (Tamiasciurus hudsonicus). Nevertheless, the alternative hypotheses that neutral evolution or factors other than squirrels have caused crossbill population differentiation have not been thoroughly tested. We compared crossbill and pine cone morphology between island populations where squirrels are absent or present, and mainland sites where squirrels are present, in order to distinguish among these hypotheses. All comparisons supported an effect of squirrel absence, not island status, on crossbill and cone morphology. Hence our results provide further evidence that strong localized coevolutionary interactions in a geographic mosaic have driven adaptive population differentiation. In addition, vocal differentiation of crossbills was related to the absence of squirrels, but not to island status. As morphological and vocal differentiation is correlated with reproductive isolation in crossbills, the geographic mosaic of coevolution also seems to promote ecological speciation.
Psychological effects of repeated general anesthesia in children
Authors: KAYAALP LEVENT , BOZKURT PERVIN , ODABASI GURKAN , DOGANGUN BURAK , CAVUSOGLU PERVIN , BOLAT NURULLAH , BAKAN MEFKUR
Published: April 2006

Background:  Although methods for reducing preoperative anxiety have been a major interest of pediatric anesthesiologists, there are no reports of the effects of repeated anesthesia on psychological development of children.

Methods:  To determine the overall effect of multiple anesthetics on the psychology of children, we undertook to compare the children undergoing repeated anesthesia (Group S) for the treatment of corrosive esophagitis with a control group (Group C) with chronic renal disease and frequent hospital admissions. Psychological tests and diagnosis of children Group S (n = 23) were compared prospectively with Group C (n = 20). All children had been appropriately treated over the previous 5 years and 50% of patients in Group C had general anesthesia once and those in Group S underwent at least 5 GAs. Parents completed a child behavior checklist (CBCL) and Marital Conflict Questionnaire; the children were evaluated by a child psychiatrist using DSM‐IV criteria and completed the Child Depression Inventory (CDI).

Results:  The children in Group S underwent a total of 251 (11 ± 7) GAs over 4–60 months. The incidence of psychopathology was nine and 10 children in groups S and C, respectively. The CBCL and CDI scores were parallel with a psychiatric diagnosis. Marital conflict scores were higher in Group S.

Conclusions:  Both chronic disease states affect psychology of children. Repeated anesthesia in addition to chronic disease does not seem to disturb the child's psychological health further when tentative and precautious approach modalities are undertaken.
Continuous infraclavicular brachial plexus block in a child
Authors: FISHER PHOEBE , WILSON SAMUEL E. , BROWN MELINDA , DITUNNO THERESA
Published: April 2006

Continuous regional anesthesia for both intra‐ and postoperative use in adults is becoming more common. As with many new anesthesia techniques, however, there is often a lag time before the same techniques are utilized in children. Our patient was a 10‐year‐old child requiring reoperation on her fifth digit with planned 48‐h admission for range of motion exercises. We wanted to have a continuous regional blockade to control the patient's pain during the postoperative manipulations of the digit. A search of the literature from the last 10 years did not show any reports of the placements of a continuous brachial plexus block in children. In this case report, we present the successful placement and use of a continuous infraclavicular catheter in a child undergoing upper extremity surgery.
The impact of long chain n‐3 polyunsaturated fatty acid supplementation on inflammation, insulin sensitivity and CVD risk in a group of overweight women with an inflammatory phenotype
Authors: Browning L. M. , Krebs J. D. , Moore C. S. , Mishra G. D. , O’Connell M. A. , Jebb S. A.
Published: April 2006

Background:  Inflammation is strongly related to obesity and the risk of cardiovascular disease (CVD). The metabolic benefits of long chain (LC) n‐3 polyunsaturated fatty acid (PUFA) may be attributable to its anti‐inflammatory properties.

Objective:  To investigate whether an individual’s habitual inflammatory status influences the impact of a LC n‐3 PUFA intervention on CVD risk.

Design:  The study was a randomized crossover design. Subjects received LC n‐3 PUFA capsules or a placebo for 12 weeks, with 4‐week washout between phases. Thirty women, in the top and bottom tertiles of baseline sialic acid concentration, formed raised inflammatory status (top, n = 12) and reference (bottom, n = 18) groups. Baseline data were analysed using one‐way anova, differences between treatment phases were calculated at each timepoint and analysed using a random effects model.

Results:  At baseline, the raised inflammatory status group had significantly higher body mass index and area under the curve (AUC) insulin than the reference group. With LC n‐3 PUFA supplementation, both groups showed significantly higher plasma eicosapentaenoic acid and docosahexaenoic acid at 4 and 12 weeks (p < 0.001), and lower triacylglycerols (4 weeks p < 0.01 and 12 weeks p < 0.05). The difference in AUC insulin between the two treatment phases at 12 weeks was significantly greater in the raised inflammatory status group compared to the reference group (p < 0.05). Inflammatory markers were significantly lower after 12 weeks LC n‐3 PUFA supplementation compared to baseline (C‐reactive protein p < 0.05 and interleukin‐6 p < 0.01), but there was no significant group effect.

Conclusions:  Habitual inflammatory status influences the impact of LC n‐3 PUFA supplementation, but it is not clear whether the effect of LC n‐3 PUFA on AUC insulin is mediated through inflammatory mechanisms.
Effects of S 15511, a therapeutic metabolite of the insulin‐sensitizing agent S 15261, in the Zucker Diabetic Fatty rat
Authors: Pickavance L. C. , Wilding J. P. H.
Published: April 2006

Aim:  S 15261 is a novel oral antihyperglycaemic drug with both insulin secretagogue and insulin‐sensitizing effects. The study was designed to determine the biological activity of its two major metabolites, S 15511 and Y 415, and whether or not they have an additive effect.

Methods:  Zucker Diabetic Fatty rats were treated for 28 days with S 15511 (10 mg/kg), Y 415 (10 mg/kg), or a combination at the same doses for a period of 4 weeks starting at 6–7 weeks of age. An additional group was pair‐fed to the level of S 15511‐treated animals to determine if possible effects were due to reduced food intake.

Results:  S 15511 alone and combined with Y 415 reduced energy intake and weight gain (−13% vs. controls; both p < 0.01). Baseline fasting plasma glucose levels were maintained by S 15511, S 15511 + Y 415 and pair‐feeding (p < 0.01) for the entire treatment period (p < 0.01). Baseline insulin was maintained by pair‐feeding only, whereas all other treated groups became hyperinsulinaemic (+110–276%; p < 0.05). Deterioration in insulin sensitivity [homeostasis model assessment (HOMA)‐IR: + 239%; p < 0.01] was attenuated by S 15511, S 15511 + Y 415 and pair‐feeding (p < 0.01) and was compensated for by improved insulin secretion (HOMA‐β; p < 0.01). Oral glucose tolerance tests, performed on days 0, 14 and 28, showed that all groups had an impaired insulin response, but by day 28, S 15511, S 15511 + Y 415 and pair‐feeding had improved glucose disposal compared to the progressive deterioration in untreated controls (−44% to −48% vs. controls; p < 0.01), associated with progression to frank diabetes in these animals.

Conclusion:  Treatment with these agents in a genetic model of type 2 diabetes reveals that they all have a transient effect compared to the progressive worsening of vehicle‐treated controls. The improvements in glucose metabolism observed with S 15511 are significant, however, suggesting it has more therapeutic activity than the Y 415 metabolite of S 15261. It is associated with less frequent progression to diabetes; i.e. Y 415 exerts a non‐significant effect alone and no significant additive effect when combined with S 15511. The mechanism of action of S 15511 may be via increased insulin sensitivity and β‐cell response preservation up to day 21. Thus, previously reported insulin secretagogue effects are likely to be attributable to the parent compound.
Natural Resources and Economic Growth: The Role of Investment
Authors: Gylfason Thorvaldur , Zoega Gylfi
Published: April 2006

Is it possible that excessive reliance on natural resources affects saving and investment in a way that retards economic growth? – and thus, in the long run, the level of output per capita. This paper reviews the literature, explores the data and compares and contrasts the explanatory power and interplay of natural resources and civil liberties, our proxy for institutional variables currently under scrutiny in the literature. We propose that natural resource dependence may be viewed as an exogenous factor that impedes economic growth and investment as well as institutions, even if we stress that natural resource abundance may be good for growth.
A review of spermatozoan morphology in Cetacea with new data for the genus Kogia
Authors: Plön S. , Bernard R. T. F.
Published: April 2006

There have been few studies on the morphology of spermatozoa of the Cetacea. Here we present a review of the existing published material and present new data for spermatozoa of Kogia breviceps, Kogia sima and Delphinus delphis. In contrast to the usual spiral arrangement of mitochondria in the midpiece of mammalian sperm, cetaceans exhibit a unique arrangement of spherical mitochondria arranged in tiers and columns along the midpiece, which is primitive in appearance. In addition, the midpiece of the cetacean spermatozoon is much shorter than that of other mammalian orders. Detailed knowledge of the morphology of the spermatozoa of cetaceans may help elucidate aspects of male reproduction and the fertilization process in this group.
Microsatellite loci for a sparsely distributed species, Kalopanax pictus (Araliaceae) in Japanese temperate forests
Authors: FUJIMORI N. , KENTA T. , KONDO T. , KAMEYAMA Y. , ISAGI Y. , NAKASHIZUKA T.
Published: April 2006

We identified seven polymorphic microsatellite loci that can be used to evaluate distances of pollen movement and seed dispersal in a sparsely distributed tree species, Kalopanax pictus (Araliaceae), in Japanese temperate forests. The leaves of K. pictus are damaged by a fungal disease, Mycosphaerella acanthopanacis, and the intensity and frequency of the infections are positively correlated with adult tree density. In order to infer the optimal density of K. pictus and the processes of regeneration in the presence of the fungal disease, we developed microsatellite markers. The numbers of alleles per locus ranged from seven to 17 with an average of 10.6. Expected heterozygosity ranged from 0.63 to 0.94 with an average of 0.79. Total exclusion probabilities from the seven loci for the first and second parents of seedlings were 0.9880 and 0.9999, respectively. Our results indicate that these loci will be useful for the analysis of gene flow.
Comparison of urethane/chloralose and pentobarbitone anaesthesia for examining effects of bacterial lipopolysaccharide in mice
Authors: Kazerani Hamid R. , Furman Brian L.
Published: April 2006

Although anaesthetics are widely used to alleviate stress in endotoxaemic animals, these drugs themselves may interfere with the effects of lipopolysaccharide (LPS). The effects of LPS on serum glucose, biochemical markers of hepatic, renal and pancreatic exocrine function, and lung myeloperoxidase (MPO) activity were compared using anaesthesia with either urethane/chloralose or pentobarbitone. Groups of 10–13 of C57B1/6 mice (22.3 ± 0.18 g) were treated with 40 mg/kg LPS or the same volume of saline (10 mL/kg, i.p.) at time 0, Animals were anaesthetized either with urethane (1000 mg/kg) and chloralose (50 mg/kg) or with pentobarbitone (90 mg/kg, i.p.) after 2 h and blood and lung samples obtained after 6 h. In pentobarbitone‐anaesthetized mice, LPS caused hypoglycaemia and increased serum levels of alanine aminotransferase (ALT), lipase and creatinine suggesting damage/dysfunction of liver, exocrine pancreas and kidney respectively. Lung tissue MPO activity, an indicator of neutrophil infiltration, was also increased. Urethane/chloralose‐treated mice demonstrated hypoglycaemia and enhanced serum levels of ALT and creatinine in response to LPS, but failed to show LPS‐induced increases in serum lipase and lung MPO activity. It is concluded that while pentobarbitone may be successfully used in experimental models of endotoxaemia in mice, anaesthesia with urethane and chloralose may protect mice against LPS‐mediated damage/dysfunction in the exocrine pancreas and in the lung, and therefore, is not recommended in studies on endotoxaemic mice.
Long‐term effects of compost amendment of soil on functional and structural diversity and microbial activity
Authors: Ros M. , Klammer S. , Knapp B. , Aichberger K. , Insam H.
Published: April 2006

We studied the effects of applying different composts (urban organic waste, green waste, manure and sewage sludge), mineral fertilizer and compost plus mineral fertilizer on chemical, biological and soil microbiological parameters over a 12‐year period. The organic C and total N levels in soils were increased by all compost and compost + N treatments. Microbial biomass C was significantly (P ≤ 0.05) increased for some compost treatments. In addition, basal respiration and the metabolic quotient (qCO2) were significantly higher in all soils that had received sewage sludge compost. The Shannon diversity index (H), based on community level physiological profiling, showed a higher consumption of carbon sources in soils treated with compost and compost + N compared with the control. The utilization of different guilds of carbon sources varied amongst the treatments (compost, compost + N or mineral fertilizer). Cluster analysis of polymerase chain reaction‐denaturing gradient gel electrophoresis patterns showed two major clusters, the first containing the mineral fertilization and compost treatments, and the second, the composts + N treatments. No differences in bacterial community structure could be determined between the different types of compost. However, the results suggest that long‐term compost treatments do have effects on the soil biota. The results indicate that the effects on the qCO2 may be due to shifts in community composition. In this study, it was not possible to distinguish with certainty between the effects of different composts except for compost derived from sewage sludge.