bluuebunny/crossref_metadata_2025 huggingface dataset:
A short term benefit for outcrossing in a
Daphnia
metapopulation in relation to parasitism
Authors: Ebert Dieter , Altermatt Florian , Lass Sandra
Published: April 2007

Because host–parasite interactions are often specific to the host and parasite genotype, it may be important whether a host reproduces by selfing or outcrossing. The latter is associated with higher genetic diversity among the offspring and may reduce parasite success. Here, we test whether outbred offspring of
Daphnia magna
have an advantage over selfed offspring in the presence of a parasite transmitted from mothers to offspring. Using outdoor mesocosms, we set up monoclonal and polyclonal host populations of
D. magna
infected with a prevalence of 100% with the horizontally and vertically transmitted microsporidian parasite
Octosporea bayeri
. These populations diapaused after sexual reproduction and hatchlings were screened for signs of
O. bayeri
. Parasite prevalence was 98.9% for hatchlings from the monoclonal treatment, but only 85.2% among the hatchlings from the polyclonal populations, indicating a short-term benefit for outbreeding. This benefit occurs, we hypothesize, not owing to inbreeding depression, but because the vertically transmitted parasite is less able to establish itself in the relatively new genetic environment of the outbred offspring, as compared to the more stable environment when transmitted to selfed offspring. To quantify the fitness consequences of this 14% prevalence difference, we studied the within-season epidemiology of
O. bayeri
, using an epidemiological model. We then examined whether descendants of outbred offspring produce more resting eggs than the descendants of selfed offspring. The data and our model show that
Daphnia
which are uninfected at the beginning of the growth season have a large advantage when the entire season is considered. Our data support the Red Queen hypothesis which states that in the presence of coevolving parasites, outbreeding is favoured in the host.
Evolution of solitary marginal disturbances in baroclinic frontal geostrophic dynamics with dissipation and time-varying background flow
Authors: Turnbull Mattea R , Swaters Gordon E
Published: April 2007

A two-layer frontal geostrophic flow corresponds to a dynamical regime that describes the low-frequency evolution of baroclinic ocean currents with large amplitude deflections of the interface between the layers on length-scales longer than the internal deformation radius within the context of a thin upper layer overlying a dynamically active lower layer. The finite-amplitude evolution of solitary disturbances in baroclinic frontal geostrophic dynamics in the presence of time-varying background flow and dissipation is shown to be governed by a two-equation extension of the
unstable
nonlinear Schrödinger (UNS) equation with variable coefficients and forcing. The soliton solution of the unperturbed UNS equation corresponds to a saturated isolated coherent anomaly in the baroclinic instability of surface-intensified oceanographic fronts and currents. The adiabatic evolution of the propagating soliton and the uniformly valid first-order perturbation fields are determined using a direct perturbation approach together with phase-averaged conservation relations when both dissipation and time variability are present. It is shown that the soliton amplitude parameter decays exponentially due to the presence of the dissipation but is unaffected by the time variability in the background flow. On the other hand, the soliton translation velocity is unaffected by the dissipation and evolves only in response to the time variability in the background flow. The adiabatic solution for the induced mean flow exhibits a dissipation-generated ‘shelf region’ in the far field behind the soliton, which is removed by solving the initial-value problem.
Why do men marry and why do they stray?
Authors: Winking Jeffrey , Kaplan Hillard , Gurven Michael , Rucas Stacey
Published: April 2007

Humans are quite unusual compared to other great apes in that reproduction typically takes place within long-term, iteroparous pairings—social arrangements that have been culturally reified as the institution of marriage. With respect to male behaviour, explanations of marriage fall into two major schools of thought. One holds that marriage facilitates a sexual division of labour and paternal investment, both important to the rearing of offspring that are born helpless and remain dependent for remarkably long periods (provisioning model). And the other suggests that the main benefits which men receive from entering into marriage derive from monopolizing access to women's fertility (mating effort model). In this paper, we explore extramarital sexual relationships and the conditions under which they occur as a means of testing predictions derived from these two models. Using data on men's extramarital sexual relationships among Tsimane forager–horticulturists in lowland Bolivia, we tested whether infidelity was more common when men had less of an opportunity to invest in their children or when they risked losing less fertility. We found that Tsimane men appear to be biasing the timing of their affairs to when they are younger and have fewer children, supporting the provisioning model.
Genetic isolation of a now extinct population of bottlenose dolphins (Tursiops truncatus)
Authors: Nichols Courtney , Herman Jerry , Gaggiotti Oscar E , Dobney Keith M , Parsons Kim , Hoelzel A. Rus
Published: April 2007

A number of dolphin species, though highly mobile, show genetic structure among parapatric and sometimes sympatric populations. However, little is known about the temporal patterns of population structure for these species. Here, we apply Bayesian inference and data from ancient DNA to assess the structure and dynamics of bottlenose dolphin (Tursiops truncatus) populations in the coastal waters of the UK. We show that regional population structure in UK waters is consistent with earlier studies suggesting local habitat dependence for this species in the Mediterranean Sea and North Atlantic. One genetically differentiated UK population went extinct at least 100 years ago and has not been replaced. The data indicate that this was a local extinction, and not a case of historical range shift or contraction. One possible interpretation is a declining metapopulation and conservation need for this species in the UK.
Subordinate male meerkats prospect for extra-group paternity: alternative reproductive tactics in a cooperative mammal
Authors: Young Andrew J , Spong Goran , Clutton-Brock Tim
Published: April 2007

In cooperatively breeding species, subordinates typically suffer strong constraints on within-group reproduction. While numerous studies have highlighted the additional fitness benefits that subordinates might accrue through helping, few have considered the possibility that subordinates may also seek extra-group matings to improve their chances of actually breeding. Here, we show that subordinate males in cooperative meerkat,
Suricata suricatta
, societies conduct frequent extraterritorial forays, during periods of peak female fertility, which give rise to matings with females in other groups. Genetic analyses reveal that extra-group paternity (EGP) accrued while prospecting contributes substantially to the reproductive success of subordinates: yielding the majority of their offspring (approx. 70%); significantly reducing their age at first reproduction and allowing them to breed without dispersing. We estimate that prospecting subordinates sire 20–25% of all young in the population. While recent studies on cooperative birds indicate that dominant males accrue the majority of EGP, our findings reveal that EGP can also arise from alternative reproductive tactics employed exclusively by subordinates. It is important, therefore, that future attempts to estimate the fitness of subordinate males in animal societies quantify the distribution of extra-group as well as within-group paternity, because a substantial proportion of the reproductive success of subordinates may otherwise go undetected.
Predicting unknown species numbers using discovery curves
Authors: Bebber Daniel P , Marriott Francis H.C , Gaston Kevin J , Harris Stephen A , Scotland Robert W
Published: April 2007

A common approach to estimating the total number of extant species in a taxonomic group is to extrapolate from the temporal pattern of known species descriptions. A formal statistical approach to this problem is provided. The approach is applied to a number of global datasets for birds, ants, mosses, lycophytes, monilophytes (ferns and horsetails), gymnosperms and also to New World grasses and UK flowering plants. Overall, our results suggest that unless the inventory of a group is nearly complete, estimating the total number of species is associated with very large margins of error. The strong influence of unpredictable variations in the discovery process on species accumulation curves makes these data unreliable in estimating total species numbers.
RED GLAZES AND UNDERGLAZE RED BY REDUCTION*
Authors: Harder BY C. M.
Published: April 2007

Abstract

A firing procedure is formulated along the lines laid down by Seger for the production of copper red glazes and underglaze red. Possible methods of control of the liver red, cherry red, and purple‐red flambé glazes are given.
A NEW METHOD FOR STUDYING THE FLOW CHARACTERISTICS OF GLASSES AND SLAGS AT ELEVATED TEMPERATURES*
Authors: Barrett Elliott P. , Taylor James A.
Published: April 2007

Abstract

Viscosities and surface tensions of glasses and slags are properties of great practical importance but they are frequently difficult to measure. The methods which yield results in absolute units are time‐consuming and are not applicable to a study of the behavior of partly devitrified silicate melts.

This paper describes an empirical method for estimating not only the relative fluidity of glasses and slags but also for determining the lowest temperature at which crystallization from a previously chilled vitreous slag will occur on reheating, the approximate rate at which devitrification proceeds at various temperatures, and the range of temperature within which devitrification is complete enough to prevent flow of the slag under its own weight.

By an extension of the method to mixtures of crystalline substances, the behavior of such mixtures upon heating may be studied advantageously. By a further extension of the technique, the temperature at which the solid‐liquid interfacial tension becomes low enough to permit wetting of a solid by a glass or slag may be determined. The applicability of these techniques to vitreous enameling problems is indicated.
THE INFLUENCE OF DRYING TREATMENT AND BISCUIT STORAGE ATMOSPHERE ON THE PHYSICAL PROPERTIES OF A SEMIPORCELAIN BODY*
Authors: Latimer Horace L. , Watts Arthur S.
Published: April 2007

Abstract

This investigation employed the following drying tests: (1) in the presence of CaCl2, (2) in air circulated at 100°F, (3) in air circulated at 225°F, and (4) in a humidity drier, employing 129°F, dry bulb, with 85% humidity for two days and decreasing humidity to bone dryness in five days. The trials were fired under regular plant conditions and stored as follows: (1) in a closed chamber with adequate supply of CaCl2, (2) in outside weather, winter and spring, (3) alternate soaking in water for two days and drying to 5% of total absorption for the period of test, and (4) in a saturated atmosphere. Data on modulus of rupture, absorption, and porosity are assembled in tables and graphs for comparison, indicating marked influences on these properties both by drying and storage treatments. Explanations of the results are suggested.
TESTING REFRACTORIES AGAINST THE CORROSIVE ACTION OF ELECTRIC FURNACE PHOSPHATE SLAGS*
Authors: Pole GordonR. , Moore D. G.
Published: April 2007

Abstract

A new method was developed as a means of testing refractories against molten phosphate furnace slag at 1450°C. The slag was essentially a monocalcium silicate. Brick with 131/2‐ by 41/2‐ by 21/2‐inch dimensions were used as test specimens. An oil‐fired pot‐type furnace, 24 inches in diameter and 12 inches deep, was used for the test. Four refractories were tested at one time by this method. The test brick were suspended from a silicon carbide crown and dipped 21/2 inches into the molten slag bath. The degree of corrosion was measured by determining the volume and weight losses of the refractory. Petrographic studies were made on a number of the brick after testing. Quantitative data on twenty‐two brands of refractories tested by this means are given.
THE EFFECT OF HYDROCHLORIC ACID AND AMMONIA ON PROPERTIES OF SOME REWORKED BODIES*
Authors: Twells Robert
Published: April 2007

Abstract

When certain electrical‐porcelain bodies are shaped in the bone‐dry state, the scrap from the process is finely divided and has a low bulk density. Bodies reprepared from such scrap tend to blister and the glaze tends to contain pinholes after being fired at the maturing temperature. Blistering of the reworked body in firing is not decreased by vacuum treatment of the scrap body slip, and wet grinding definitely increases the blistering. Experiments were conducted in which hydrochloric acid and ammonia were added separately to the body scrap in gradually increasing quantities. The addition of ammonia tended to eliminate blistering of the body and pinholing of the glaze after firing.
DRAFT CONTROL AS A MEANS OF FUEL CONSERVATION IN KILN FIRING*
Authors: Straight H. R.
Published: April 2007

Abstract

The importance of closely regulating the internal pressure of a kiln under fire is discussed from a standpoint of uniformity of heat treatment of the charge, reduction of fuel consumption, and efficiency in the use of combustible gases. An attempt is made at an analysis of the causes of low efficiency and high fuel consumption.
STRENGTH AND PHYSICAL PROPERTIES OF FINE GLASS FIBERS AND YARNS*
Authors: Slayter Games
Published: April 2007

Abstract

Glass fibers have been produced in large quantities running from 0.0007‐ to 0.00005‐inch fiber diameter. The strength of individual fibers and the strength of yarns produced from these fibers have received preliminary investigation. Some of the strengths obtained are quite remarkable, running into the order of 11/2 million pounds per square inch. Even these strengths fall short of the theoretical possibilities. Some possible reasons and explanations are discussed.
II, THE CORRELATION OF PHYSICAL PROPERTIES WITH ATOMIC ARRANGEMENT
Authors: Bair George J.
Published: April 2007

Abstract

Physical properties of lead oxide‐silica glasses were studied in an attempt to correlate these properties and explain the anomalies occurring in their temperature and time curves on the basis of the structure of glass as derived in Part I of this investigation. The transformation point is denned as a critical temperature, and an explanation is offered for the dependence of this temperature on heat treatment and conditions of test. The change in the apparent viscosity of a glass fiber with time is explained on the basis of the distorted glass structure. The Adams and Williamson equation for strain release is adapted to substantiate the theory of the structure of glass consisting of a continuous, randomly oriented, three‐dimensional network of atoms.
EFFECT OF SOLUBLE SALTS FORMED DURING AGING ON THE SCUMMING OF ENAMELS*
Authors: Whitesell. R. J.
Published: April 2007

Abstract

Enamel slips were milled using three typical commercial frits. Representative samples were aged for different lengths of time and at varying temperatures. At the end of its individual aging treatment, portions of each sample were filtered, Na2O and B2O3 being determined on all filtrates.

The remaining slip from each sample was then used to spray sample plates which were fired at the critical temperature for the formation of scum on enamel. A correlation of the data on soluble salts and on scumming is made.
METHOD FOR IMPROVING THE PHYSICAL PROPERTIES OF CLAYS*
Authors: Whittemore J. W. , Bull F. W.
Published: April 2007

Abstract

The effect of an organic material, commercially known as Plasticade, on the physical properties of several clays was studied. Plasticade is principally an organic compound with a tannin and lignin base and is an acid in its reactions. It has a marked effect on all of the physical properties of the clays studied. Its effect was studied first in the laboratory and then determined from plant trials.
SOME DRYING PROPERTIES OF CLAYS: I‐III I, Effect of Small Imposed Loads on the Rate of Drying of Some Clays*
Authors: Schurecht H. G. , Lampman C. Major
Published: April 2007

Abstract

The increased rate of drying caused by low pressures on the ware is a factor in drying which must be recognized particularly with large shapes and in drier car settings of considerable heights. Pressures of the magnitude encountered under these conditions were found to increase the rate of drying as high as 58% in the case of some clays, causing the unloaded portions to have 3.30 times as much water as the loaded portions during certain periods of drying. All clays are effected to a greater or less extent, but it is most prominent in clays of low plasticity.
A CONTROLLED BOILING ACID TEST FOR PORCELAIN ENAMELS*
Authors: BRYANT E. E.
Published: April 2007

Abstract

The apparatus described in this paper was designed to accomplish certain results for boiling acid‐resistance tests as follows: (1) temperature control of the acid solution; (2) constant volume of the acid solution by eliminating evaporation; (3) confinement of the acid attack to a definite area of surface; (4) acid solution unweakened by attack on surfaces not pertinent to the test; and (5) a weighed sample may be used to determine the weight of enamel removed by acid attack, or loss of gloss may be determined. Data are included to show the accuracy and general possibilities of the test.
EFFECT OF MANGANESE, NICKEL, AND COBALT OXIDE UPON THE ADHERENCE AND REBOILING PROPERTIES OF A GROUND‐COAT ENAMEL*
Authors: Howe E. E. , Fellows R. L.
Published: April 2007

Abstract

A series of enamels was compounded in which small amounts of adherence‐promoting oxides were varied and their effect upon the adherence and reboiling properties of a base enamel glass applied to steel was studied. Results indicated that cobalt oxide was necessary in producing adherence, whereas nickel and manganese oxides increased the firing range. Reboiling was found to be dependent upon adherence. Photomicrographs showed that different phases existed in the interfacial layer when the different metallic oxides were introduced into the enamel.
CONCERNING THE STRENGTH OF THE WEAKEST BOTTLES* Applicability of the “Normal” Curve of Errors to Statistical Analyses of Strength Tests of Glassware
Authors: Preston F. W.
Published: April 2007

Abstract

The ordinary “theory of errors,” which assumes a “normal distribution” of the errors, is often applied to situations where it can not theoretically apply. In particular it has been applied to the strength of glass and glassware. While theoretically the theory is wrong, there is no entirely satisfactory theory available to replace it, and the question arises how far it can be used with advantage and exactly what are its limitations. It is necessary to answer these questions by direct experiment, i.e., by breaking a lot of glassware.
EVAPORATION BY SUBMERGED COMBUSTION: VI, DEWATERING CLAY SUSPENSIONS*
Authors: Kobe Kenneth A. , Wllson Hewitt , Sheehyt Thomas M.
Published: April 2007

Abstract

Submerged combustion methods are described and their advantages are discussed. The application of this method to the dewatering of highly colloidal kaolins has been made. Evaporation takes place with thermal efficiencies up to 96% and evaporation efficiencies up to 85%. There is no difficulty with the clay until concentrations above 45% solids are reached. Hard particles then form owing to insufficient agitation. The solids content has been carried to 67%.
ACID BESSEMER REFRACTORIES*
Authors: Chesters J. H. , McLean R. J.
Published: April 2007

Abstract

A study has been made of the refractories used in the acid Bessemer process. The failure of the tuyères, which generally precedes that of the remainder of the bottom, is found to be due mainly to the attack of ferrous oxide and manganous oxide. The rapid rate of wear is explained by the fact that an addition of 8% of ferrous oxide or manganous oxide reduces the melting point of the tuyère to 1550°C, i.e., to about the temperature of the molten steel. Laboratory investigations suggest a number of possible ways of increasing bottom life, e.g., the production and use of (a) basic tuyères of high spalling resistance, (b) plumbago tuyères, and (c) fireclay tuyères of higher alumina content.
Effects of temperature and sex on jump performance and biomechanics in the lizardAnolis carolinensis
Authors: LAILVAUX S. P. , IRSCHICK D. J.
Published: April 2007

Temperature is known to affect whole‐organism performance capacities significantly in ectotherms, but may potentially alter performance kinematics as well. Locomotor performance is a multivariate phenomenon, hence changes in temperature are probably reflected in multiple aspects of locomotion.

We studied the thermal sensitivity of several kinetic and kinematic jump variables, including acceleration and power output, in male and female green anole lizards,Anolis carolinensisVoigt 1832. We hypothesized that temperature would have similar effects on kinetic and kinematic variables.

We also tested the hypotheses that males and females would differ in jump performance, but only because of sexual dimorphism for body size, and that males and females would also differ in optimal performance temperature and body temperature (Tb) maintained in the field.

Both kinetic and kinematic jump variables exhibited significant temperature dependence, as expected, suggesting that overall jump dynamics are altered by temperature in green anoles. Power, in particular, increased markedly over the 15–25 °C temperature range in males.

Sex differences in jumping were driven largely by sexual dimorphism in body size. However, females exhibited significantly narrower thermal tolerance ranges than males, although they maintained aTbsimilar to males in the field.

These data illustrate the necessity of carefully controllingTbduring jumping experiments at single temperatures in ectotherms, as temperature affects a suite of kinematic and biomechanical traits determining overall jump performance.
Plant species richness, elevated CO2, and atmospheric nitrogen deposition alter soil microbial community composition and function
Authors: CHUNG HAEGEUN , ZAK DONALD R. , REICH PETER B. , ELLSWORTH DAVID S.
Published: April 2007

We determined soil microbial community composition and function in a field experiment in which plant communities of increasing species richness were exposed to factorial elevated CO2 and nitrogen (N) deposition treatments. Because elevated CO2 and N deposition increased plant productivity to a greater extent in more diverse plant assemblages, it is plausible that heterotrophic microbial communities would experience greater substrate availability, potentially increasing microbial activity, and accelerating soil carbon (C) and N cycling. We, therefore, hypothesized that the response of microbial communities to elevated CO2 and N deposition is contingent on the species richness of plant communities. Microbial community composition was determined by phospholipid fatty acid analysis, and function was measured using the activity of key extracellular enzymes involved in litter decomposition. Higher plant species richness, as a main effect, fostered greater microbial biomass, cellulolytic and chitinolytic capacity, as well as the abundance of saprophytic and arbuscular mycorrhizal (AM) fungi. Moreover, the effect of plant species richness on microbial communities was significantly modified by elevated CO2 and N deposition. For instance, microbial biomass and fungal abundance increased with greater species richness, but only under combinations of elevated CO2 and ambient N, or ambient CO2 and N deposition. Cellobiohydrolase activity increased with higher plant species richness, and this trend was amplified by elevated CO2. In most cases, the effect of plant species richness remained significant even after accounting for the influence of plant biomass. Taken together, our results demonstrate that plant species richness can directly regulate microbial activity and community composition, and that plant species richness is a significant determinant of microbial response to elevated CO2 and N deposition. The strong positive effect of plant species richness on cellulolytic capacity and microbial biomass indicate that the rates of soil C cycling may decline with decreasing plant species richness.
Interacting effects of elevated CO2, nutrient availability and plant species on a generalist invertebrate herbivore
Authors: SCHÄDLER MARTIN , ROEDER MAREIKE , BRANDL ROLAND , MATTHIES DIETHART
Published: April 2007

By affecting plant growth and phytochemistry elevated CO2 may have indirect effects on the performance of herbivores. These effects show considerable variability across studies and may depend on nutrient availability, the carbon/nutrient‐balance in plant tissues and the secondary metabolism of plants. We studied the responses to elevated CO2 and different nutrient availability of 12 herbaceous plant species differing in their investment into secondary compounds. Caterpillars of the generalist herbivore Spodoptera littoralis were reared on the leaves produced and their consumption and growth rates analysed. Elevated CO2 resulted in a similar increase of biomass in all plant species, whereas the positive effect of fertilization varied among plant species. Specific leaf weight was influenced by elevated CO2, but the effect depended on nutrient level and identity of plant species. Elevated CO2 increased the C/N ratio of the leaves of most species. Caterpillars consumed more leaf material when plants were grown under elevated CO2 and low nutrients. This indicates compensatory feeding due to lower tissue quality. However, the effects of elevated CO2, nutrient availability and plant species identity on leaf consumption interacted. Both the effects of CO2 and nutrient availability on the relative growth rate of the herbivore depended on the plant species. The feeding rate of S. littoralis on plant species that do not produce nitrogen‐containing secondary compounds (NCSC) was higher under low nutrient availability. In contrast, in plants producing NCSC nutrient availability had no effect on the feeding rate. This suggests that compensatory feeding in response to low nutrient contents may not be possible if plants produce NCSC. We conclude that elevated CO2 causes species‐specific changes in the quality of plant tissues and consequently in changes in the preferences of herbivores for plant species. This could result in changes in plant community composition.
Methanogenic activity and biomass in Holocene permafrost deposits of the Lena Delta, Siberian Arctic and its implication for the global methane budget
Authors: WAGNER DIRK , GATTINGER ANDREAS , EMBACHER ARNDT , PFEIFFER EVA‐MARIA , SCHLOTER MICHAEL , LIPSKI ANDRÉ
Published: April 2007

Permafrost environments within the Siberian Arctic are natural sources of the climate relevant trace gas methane. In order to improve our understanding of the present and future carbon dynamics in high latitudes, we studied the methane concentration, the quantity and quality of organic matter, and the activity and biomass of the methanogenic community in permafrost deposits. For these investigations a permafrost core of Holocene age was drilled in the Lena Delta (72°22′N, 126°28′E). The organic carbon of the permafrost sediments varied between 0.6% and 4.9% and was characterized by an increasing humification index with permafrost depth. A high CH4 concentration was found in the upper 4 m of the deposits, which correlates well with the methanogenic activity and archaeal biomass (expressed as PLEL concentration). Even the incubation of core material at −3 and −6°C with and without substrates showed a significant CH4 production (range: 0.04–0.78 nmol CH4 h−1 g−1). The results indicated that the methane in Holocene permafrost deposits of the Lena Delta originated from modern methanogenesis by cold‐adapted methanogenic archaea. Microbial generated methane in permafrost sediments is so far an underestimated factor for the future climate development.
Savanna fires and their impact on net ecosystem productivity in North Australia
Authors: BERINGER JASON , HUTLEY LINDSAY B. , TAPPER NIGEL J. , CERNUSAK LUCAS A.
Published: April 2007

Savannas comprise a large area of the global land surface and are subject to frequent disturbance through fire. The role of fire as one of the primary natural carbon cycling mechanisms is a key issue in considering global change feedbacks. The savannas of Northern Australia burn regularly and we aimed to determine their annual net ecosystem productivity (NEP) and the impact of fire on productivity. We established a long‐term eddy covariance flux tower at Howard Springs, Australia and present here 5 years of data from 2001 to 2005. Fire has direct impacts through emissions but also has indirect effects through the loss of productivity due to reduced functional leaf area index and the carbon costs of rebuilding the canopy. The impact of fire on the canopy latent energy exchange was evident for 40 days while the canopy was rebuilt; however, the carbon balance took approximately 70 days to recover. The annual fire free NEP at Howard Springs was estimated at −4.3 t C ha−1 yr−1 with a range of −3.5 to −5.1 t C ha−1 yr−1 across years. We calculated the average annual indirect fire effect as +0.7 t C ha−1 yr−1 using a neural network model approach and estimated average emissions of fine and coarse fuels as +1.6 t C ha−1 yr‐1. This allowed us to calculate a net biome production of −2.0 t C ha−1 yr‐1. We then partitioned this remaining sink and suggest that most of this can be accounted for by woody increment (1.2 t C ha−1 yr‐1) and shrub encroachment (0.5 t C ha−1 yr‐1). Given the consistent sink at this site, even under an almost annual fire regime, there may be management options to increase carbon sequestration by reducing fire frequency.
Plant nitrogen acquisition and interactions under elevated carbon dioxide: impact of endophytes and mycorrhizae
Authors: CHEN XIN , TU CONG , BURTON MICHAEL G. , WATSON DOROTHY M. , BURKEY KENT O. , HU SHUIJIN
Published: April 2007

Both endophytic and mycorrhizal fungi interact with plants to form symbiosis in which the fungal partners rely on, and sometimes compete for, carbon (C) sources from their hosts. Changes in photosynthesis in host plants caused by atmospheric carbon dioxide (CO2) enrichment may, therefore, influence those mutualistic interactions, potentially modifying plant nutrient acquisition and interactions with other coexisting plant species. However, few studies have so far examined the interactive controls of endophytes and mycorrhizae over plant responses to atmospheric CO2enrichment. UsingFestuca arundinaceaSchreb andPlantago lanceolataL. as model plants, we examined the effects of elevated CO2on mycorrhizae and endophyte (Neotyphodium coenophialum)and plant nitrogen (N) acquisition in two microcosm experiments, and determined whether and how mycorrhizae and endophytes mediate interactions between their host plant species. Endophyte‐free and endophyte‐infectedF. arundinaceavarieties,P. lanceolataL., and their combination with or without mycorrhizal inocula were grown under ambient (400 μmol mol−1) and elevated CO2(ambient + 330 μmol mol−1). A15N isotope tracer was used to quantify the mycorrhiza‐mediated plant acquisition of N from soil. Elevated CO2stimulated the growth ofP. lanceolatagreater thanF. arundinacea, increasing the shoot biomass ratio ofP. lanceolatatoF. arundinaceain all the mixtures. Elevated CO2also increased mycorrhizal root colonization ofP. lanceolata, but had no impact on that ofF. arundinacea. Mycorrhizae increased the shoot biomass ratio ofP. lanceolatatoF. arundinaceaunder elevated CO2. In the absence of endophytes, both elevated CO2and mycorrhizae enhanced15N and total N uptake ofP. lanceolatabut had either no or even negative effects on N acquisition ofF. arundinacea, altering N distribution between these two species in the mixture. The presence of endophytes inF. arundinacea, however, reduced the CO2effect on N acquisition inP. lanceolata, although it did not affect growth responses of their host plants to elevated CO2. These results suggest that mycorrhizal fungi and endophytes might interactively affect the responses of their host plants and their coexisting species to elevated CO2.
Recent decline in precipitation and tree growth in the eastern Mediterranean
Authors: SARRIS DIMITRIOS , CHRISTODOULAKIS DIMITRIOS , KÖRNER CHRISTIAN
Published: April 2007

We present evidence of a recent drying in the eastern Mediterranean, based on weather and tree‐ring data for Samos, an island of the eastern Aegean Sea. Rainfall declined rapidly after the late 1970s following trends for the entire Mediterranean and was associated with reduced tree‐ring width in Pinus brutia. The most recent decline led to the lowest annual radial stem increment after the last 100 years (as far as records reach). As moisture availability decreased best correlations of tree growth with rainfall were obtained for progressively longer integration periods (1–2 years in moister periods, 5–6 years during the severe dryness of 20th century's last decades), suggesting increasing dependency in deep soil water. Such long‐term integration periods of tree‐growth responses to precipitation have not been reported before. They may reflect a tree‐rooting pattern adapted to cope with even several successive dry years. In late summer 2000, moisture reserves became exhausted, however, and a substantial fraction of low altitude pines died, including some 80‐year‐old trees, which underlines the exceptional extent this trend had reached. Our findings provide empirical support for Intergovernmental Panel on Climate Change projections derived from global circulation models that the Mediterranean, its eastern basin in particular, should become drier as temperature rises, as was the case in the recent past.
Optimizing dispersal and corridor models using landscape genetics
Authors: EPPS CLINTON W. , WEHAUSEN JOHN D. , BLEICH VERNON C. , TORRES STEVEN G. , BRASHARES JUSTIN S.
Published: April 2007

Better tools are needed to predict population connectivity in complex landscapes. ‘Least‐cost modelling’ is one commonly employed approach in which dispersal costs are assigned to distinct habitat types and the least‐costly dispersal paths among habitat patches are calculated using a geographical information system (GIS). Because adequate data on dispersal are usually lacking, dispersal costs are often assigned solely from expert opinion. Spatially explicit, high‐resolution genetic data may be used to infer variation in animal movements. We employ such an approach to estimate habitat‐specific migration rates and to develop least‐cost connectivity models for desert bighorn sheepOvis canadensis nelsoni.

Bighorn sheep dispersal is thought to be affected by distance and topography. We incorporated both factors into least‐cost GIS models with different parameter values and estimated effective geographical distances among 26 populations. We assessed which model was correlated most strongly with gene flow estimates among those populations, while controlling for the effect of anthropogenic barriers. We used the best‐fitting model to (i) determine whether migration rates are higher over sloped terrain than flat terrain; (ii) predict probable movement corridors; (iii) predict which populations are connected by migration; and (iv) investigate how anthropogenic barriers and translocated populations have affected landscape connectivity.

Migration models were correlated most strongly with migration when areas of at least 10% slope had 1/10th the cost of areas of lower slope; thus, gene flow occurred over longer distances when ‘escape terrain’ was available. Optimal parameter values were consistent across two measures of gene flow and three methods for defining population polygons.

Anthropogenic barriers disrupted numerous corridors predicted to be high‐use dispersal routes, indicating priority areas for mitigation. However, population translocations have restored high‐use dispersal routes in several other areas. Known intermountain movements of bighorn sheep were largely consistent with predicted corridors.

Synthesis and applications.Population genetic data provided sufficient resolution to infer how landscape features influenced the behaviour of dispersing desert bighorn sheep. Anthropogenic barriers that block high‐use dispersal corridors should be mitigated, but population translocations may help maintain connectivity. We conclude that developing least‐cost models from similar empirical data could significantly improve the utility of these tools.
Designing a network for butterfly habitat restoration: where individuals, populations and landscapes interact
Authors: MCINTIRE ELIOT J. B. , SCHULTZ CHERYL B. , CRONE ELIZABETH E.
Published: April 2007

Restoring biologically appropriate habitat networks is fundamental to the persistence and connectivity of at‐risk species surviving in highly fragmented environments. For many at‐risk species, this landscape planning problem requires combining detailed biological information about the species with the landscape, economic and social realities of the restoration effort.

Here, we assess the ability of potential restored landscapes to create persistent and connected populations of the federally endangered Fender's blue butterfly (Icaricia icarioides fenderi) in Oregon's Willamette Valley. Like many other at‐risk species, a very small amount (0·5%) of historic habitat remains and much of this habitat is highly degraded.

To do this, we combine extensive demography and behaviour data from prior studies of Fender's blue with landscape maps of potential restoration sites by building and running a spatially explicit landscape model. We chose a simulation approach because previous attempts using more traditional population modelling did not provide sufficiently informative answers for this restoration problem.

From our simulations, we: (a) provide a solution to the general landscape restoration problem of determining whether patches that are available according to social, economic and ecological realities are sufficient to restore persistence and connectivity; (b) supported our predictions from our previous models about persistence of our large patches and expanded our inference to include connectivity and persistence of small patches; and (c) found several emergent properties of our system, including identifying stepping‐stone patches, observing asymmetric connectivity and uncovering reciprocal effects of connectivity and population dynamics.

 Synthesis and applications. Assuming no large disturbances, and relying on our 14 years of data collection and models, restoring all currently degraded and potentially available habitat patches to high quality native prairie would be sufficient for long‐term persistence of Fender's blue butterfly in the West Eugene area, Oregon. This conclusion resolves many of the shortcomings of our previous population and metapopulation models that were not able to combine the necessary landscape complexity with species behaviour to address this restoration problem.
AMLODIPINE PREVENTS MONOCROTALINE‐INDUCED PULMONARY ARTERIAL HYPERTENSION AND PROLONGS SURVIVAL IN RATS INDEPENDENT OF BLOOD PRESSURE LOWERING
Authors: Mawatari Eiichiro , Hongo Minoru , Sakai Akio , Terasawa Fumiko , Takahashi Masafumi , Yazaki Yoshikazu , Kinoshita Osamu , Ikeda Uichi
Published: April 2007

The present study was designed to examine the role of amlodipine in preventing and reversing monocrotaline (MCT)‐induced pulmonary arterial hypertension (PAH) in rats.

Rats were injected with MCT (40 mg/kg, s.c.) and randomly given either 6 mg/kg per day of amlodipine in drinking water or placebo for 3 weeks. Any animals treated with MCT that survived for 3 weeks were given either amlodipine or placebo for the next 3 weeks.

Blood pressure was not different between the groups. Amlodipine immediately following MCT markedly inhibited PAH with severe pulmonary vascular remodelling. The survival rate at 3 weeks after treatment was increased significantly in the amlodipine group compared with the placebo group (77%vs 43%; P < 0.01). The placebo group showed markedly diminished expression of endothelial nitric oxide synthase (eNOS) protein and mRNA levels, increased numbers of proliferating cell nuclear antigen‐positive cells, enhanced mRNA expression of matrix metalloproteinase‐2 and pro‐inflammatory cytokines in the lung tissue and upregulation of P‐selectin on the endothelium of the pulmonary arteries, whereas these effects were suppressed in the amlodipine‐treated group. Furthermore, late treatment with amlodipine did not palliate PAH or improve survival.

Amlodipine inhibited the development of PAH and improved survival in rats independent of its effect on lowering blood pressure. These effects were associated with marked inhibition of the downregulation of eNOS and improvement of pulmonary vascular endothelial activation, as well as anti‐inflammatory, antiproliferative and antifibrotic effects in the lung tissue. However, amlodipine failed to reverse established PAH. This study may provide an insight into therapeutic strategy of amlodipine in PAH.
Arvanil, anandamide and N‐arachidonoyl‐dopamine (NADA) inhibit emesis through cannabinoid CB1 and vanilloid TRPV1 receptors in the ferret
Authors: Sharkey K. A. , Cristino L. , Oland L. D. , Van Sickle M. D. , Starowicz K. , Pittman Q. J. , Guglielmotti V. , Davison J. S. , Di Marzo V.
Published: April 2007

Cannabinoid (CB) agonists suppress nausea and vomiting (emesis). Similarly, transient receptor potential vanilloid‐1 (TRPV1) receptor agonists are anti‐emetic. Arvanil, N‐(3‐methoxy‐4‐hydroxy‐benzyl)‐arachidonamide, is a synthetic ‘hybrid’ agonist of CB1 and TRPV1 receptors. Anandamide and N‐arachidonoyl‐dopamine (NADA) are endogenous agonists at both these receptors. We investigated if arvanil, NADA and anandamide were anti‐emetic in the ferret and their mechanism of action. All compounds reduced the episodes of emesis in response to morphine 6 glucuronide. These effects were attenuated by AM251, a CB1 antagonist that was pro‐emetic per se, and TRPV1 antagonists iodoresiniferatoxin and AMG 9810, which were without pro‐emetic effects. Similar sensitivity to arvanil and NADA was found for prodromal signs of emesis. We analysed the distribution of TRPV1 receptors in the ferret brainstem and, for comparison, the co‐localization of CB1 and TRPV1 receptors in the mouse brainstem. TRPV1 immunoreactivity was largely restricted to the nucleus of the solitary tract of the ferret, with faint labeling in the dorsal motor nucleus of the vagus and sparse distribution in the area postrema. A similar distribution of TRPV1, and its extensive co‐localization with CB1, was observed in the mouse. Our findings suggest that CB1 and TRPV1 receptors in the brainstem play a major role in the control of emesis by agonists of these two receptors. While there appears to be an endogenous ‘tone’ of CB1 receptors inhibiting emesis, this does not seem to be the case for TRPV1 receptors, indicating that endogenously released endocannabinoids/endovanilloids inhibit emesis preferentially via CB1 receptors.
Can targeted intervention in CRC patients’ relatives influence screening behaviour? A pilot study
Authors: Stephens J. H. , Moore J. W. E.
Published: April 2007

Objective  This study aimed to assess the utility of a standardised risk information tool with respect to the uptake of screening activities administered to an accessible population of first‐degree relatives of patients with sporadic colorectal cancer.

Method  Patients admitted for colorectal cancer resection were invited to enrol their family unit in the study. Families were randomised either to receive standard care or the intervention tool. The intervention group received a structured one page pamphlet outlining the risk associated with a family history of colorectal cancer, and the availability of and potential benefits from screening. Three months after the initial contact with the index patient, family members were invited to participate in a telephone interview. Primary end‐points were both intention to screen and uptake of screening activities.

Results  Forty‐seven families had 156 eligible first degree relatives. Ninety‐one consented to participate and were enrolled: 59 received standard care, 32 received the intervention. Age and sex were similar between groups. There was no significant difference in previous screening activities. The intervention tool had no influence on perceived self‐risk of developing colorectal cancer or uptake of screening activities within the study period.

Conclusion  This study suggests that the provision of targeted risk information to first‐degree relatives is not likely to positively influence screening behaviour. Health care providers need to find alternative methods of disseminating information to this high‐risk group.
Avoiding ‘Star Wars’– Celebrity Creation as Media Strategy
Authors: Franck Egon , Nüesch Stephan
Published: April 2007

Media companies generally enjoy increasing profits if more customers watch a program. The viewer drawing capability of stars serves as a prominent instrument to increase the audience. The literature distinguishes between two different types of stars: highly talented and therefore ‘self‐made’ superstars, and famous but ‘manufactured’ and thus rather trivial celebrities. Whereas ‘self‐made’ superstars attract viewers by providing services of superior quality, ‘manufactured’ celebrities draw attention by fabricated fame. Illustrating thePop Idolseries and comparing the abilities of superstars and celebrities to generate and to capture value, we show why ‘manufacturing’ celebrities is a lucrative business for the media.
The Geopolitical Framing of Localized Struggles: NGOs in Bosnia and Herzegovina
Authors: Jeffrey Alex
Published: April 2007

The outbreak of war in Bosnia and Herzegovina was widely regarded by the international community as a ‘humanitarian nightmare’. Imagining the conflict in these terms ensured that it was non‐governmental organizations (NGOs) and aid agencies, rather than military forces, which intervened in the violence. In recent years, international agencies have been keen to reposition Bosnia as a country ‘in transition’ while advancing a series of initiatives aimed at democratizing Bosnian society. This article explores the repercussions of these geopolitical imaginaries and their associated policies on the practices of NGOs in the northern Bosnian town of Brčko. Drawing on the conceptual vocabulary of Pierre Bourdieu, it argues that NGOs have struggled to accumulate social and cultural capital, vital to ensuring donor funding and maintaining links with the local state. The author encourages reflection on the durability of international geopolitical scripts in shaping local outcomes in post‐conflict scenarios.