bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pantoea agglomerans‐associated bacteria in grape phylloxera (Daktulosphaira vitifoliae, Fitch)
Authors: Vorwerk S. , Martinez‐Torres D. , Forneck A. 
Published: January 2007

Abstract1 Grape phylloxera lack intracellular symbionts, but the leaf‐galling form appears to be associated with a single microbial species.2 16S and 18SrDNA sequences were used for identification of symbiotic material.3 A single bacterial species, closely related to Pantoea agglomerans, was identified in adult parthenogenetic individuals, their eggs and leaf gall tissue of several populations.4 A 16S rDNA primer pair was designed to test grape phylloxera populations more specifically for the presence of P. agglomerans.5 16S rDNA sequences of the identified bacteria were very similar to already‐known secondary symbionts occurring in aphids, thrips and other insects.6 The identified bacteria were culturable on simple media, which demonstrates that the relationship between grape phylloxera and P. agglomerans is not as firm as that of the obligately endosymbiotic Buchnera aphidicola and other aphids.
Effect of farm diversity on harvesting of coffee leaves by the leaf‐cutting ant Atta cephalotes
Authors: Varón Edgar H. , Eigenbrode Sanford D. , Bosque‐Pérez Nilsa A. , Hilje Luko 
Published: January 2007

Abstract1 In Mesoamerica, shade trees are often included within coffee (Coffea arabica) agroforestry systems. Shade trees potentially protect the main crop by increasing vegetational diversity and reducing insect herbivory through one or more mechanisms.2 The effect of on‐farm vegetational diversity on harvesting of coffee leaves by the leaf‐cutting ant, Atta cephalotes L., was examined on 15 coffee farms varying in vegetational diversity near Turrialba, Costa Rica. The farms ranged from coffee monocultures to complex‐shade coffee systems with three or more tree species present. The vegetational diversity of each farm was quantified using a leaf area index.3 The species composition and biomass of the plant material being carried into colonies by ants was collected, identified to species, and its biomass was quantified four times during one year for at least two colonies in each of the 15 farms.4 The proportion of plant biomass that was coffee being retrieved by A. cephalotes differed significantly among farm management types, and was highest (40%) in monocultures and lowest (< 1%) in farms with complex shade. Coffee was always harvested in a lower proportion than predicted based upon its relative abundance on the farms.5 In dual‐choice bioassays with laboratory colonies, A. cephalotes significantly preferred the leaves of the predominant shade tree species on the farms, poró (Erythrina poeppigiana) over coffee.6 The results indicate risk of injury by A. cephalotes can be reduced in vegetationally diverse coffee agroecosystems due at least in part to a foraging preference by the ants for plants other than coffee.
Temperature as a predictor of survival of the pine processionary moth in the Italian Alps
Authors: Buffo Emiliano , Battisti Andrea , Stastny Michael , Larsson Stig 
Published: January 2007

Abstract1 The pine processionary moth Thaumetopoea pityocampa is expanding its geographical range in Europe, as a consequence of enhanced winter survival under a warmer climate. A combination of daytime nest temperatures and night air temperatures determines the number of hours larvae are able to feed (hours above realized feeding threshold, RFT).2 We tested the RFT‐based model for survival across multiple areas of the insect’s range in the Italian Alps over a 2‐year period. In a series of translocation experiments using natural temperature gradients as spatial analogues for global warming, we transferred colonies of T. pityocampa larvae to sites within zones of historical distribution, recent distribution, and outside the present range. The sites included traditional (Pinus nigra, Pinus sylvestris) as well as novel (Pinus mugo, Pinus uncinata, Pinus cembra) hosts.3 Survival during precold (August to November), cold (December to February) and postcold (March to May) periods were analysed against climatic variables (temperature and rainfall) and predictors developed by the model.4 Host species did not significantly affect final survival, with the exception of slower larval development, and resulting lower cold tolerance, on P. cembra than on P. mugo at the same site.5 Across all the sites and hosts, final survival of colonies depended on the number of feeding hours during the cold period (RFT), which explained 82% of the variance in a regression model. We recommend using RFT, or its surrogate daily mean minimum temperature when nest temperature is not available, in predictive models of range expansion of T. pityocampa under climate change scenarios.
Longitudinal muscle shows abnormal relaxation responses to nitric oxide and contains altered levels of NOS1 and elastin in uncomplicated diverticular disease
Authors: Golder M. , Burleigh D. E. , Ghali L. , Feakins R. M. , Lunniss P. J. , Williams N. S. , Navsaria H. A. 
Published: January 2007

AbstractObjective  Recent evidence challenges the ‘low‐fibre/high‐colonic intraluminal pressure’ hypothesis of diverticular disease (DD) and raises the possibility that other mechanisms are involved. Although bowel wall smooth muscle is known to be hypercontractile in DD, the nature of its relaxation is unknown. The present study investigated colonic smooth muscle responses to nitric oxide, as well as the smooth muscle contents of neural nitric oxide and elastin associated with the disease.Method  Immunohistochemical/image analysis of antibodies to nitric oxide synthase (NOS1), co‐localized with protein gene product (PGP) and to elastin, was performed on three histological sections of sigmoid colons from 20 patients (10 DD, 10 controls) following resections for rectal tumours. Organ bath experiments examined smooth muscle responsiveness to nitroprusside, a nitric oxide donor.Results  Uncomplicated diverticular longitudinal muscle showed lower nitric oxide immunoreactivity compared with controls: median percentage surface area of NOS1 over PGP was 26.0% (range 0.5–58.3), controls 45.0% (35.0–70.1; P = 0.018). Median percentage surface area of elastin was elevated, 21.3% (10.6–45.6), controls 8.2% (1.7–13.5; P = 0.0002), together with a low sensitivity to nitroprusside [mean − log  EC50 5.3 (SD 0.5), controls 6.6 (SD 0.5), difference 1.3, 95% CI 0.8–1.7; P < 0.0001] and there were lower maximum relaxation responses to nitroprusside compared with controls: median percentage (relaxation induced by nitroprussside/contraction induced by bethanecol) was 52.0%, range (20.0–92.0), controls 100.0% (71.0–125.0), P < 0.0001. No statistically significant differences were found in circular muscle, at the sample size studied.Conclusion  This study established, for the first time, specific abnormalities in longitudinal muscle relaxation and contents of neural nitric oxide and elastin in uncomplicated DD. These findings may have important implications for both colon structure and function in the disease.
ON THE USE OF PANEL DATA METHODS TO ESTIMATE RATIONAL ADDICTION MODELS
Authors: Baltagi Badi H. 
Published: January 2007

ABSTRACTThis paper reviews some of the econometrics problems faced when estimating a rational addiction model of Becker and Murphy using panel data. This is illustrated with three empirical applications. The first application looks at cigarette consumption using macro panel data on American states over time. The second application looks at liquor consumption using macro panel data on American states over time. The third application uses micro‐panel data on Russian alcohol consumption.
INACTIVITY AND LABOUR MARKET ATTACHMENT IN BRITAIN
Authors: Little Allan 
Published: January 2007

ABSTRACTThis paper examines the transitions between the labour market and inactivity in Britain between 1995 and 2004. A substantial degree of behavioural heterogeneity exists between inactive individuals, and the social security system appears to influence both the timing and probability of moving between labour market states. The results presented here suggest that policy makers should not be misled by the term ‘hidden unemployment’, into thinking that substantial spare capacity exists on the periphery of the labour force. In light of recent proposals to reduce the number of Incapacity Benefit claimants, it is important to note a high degree of detachment among the long‐term sick and disabled, reinforced by duration dependence and poorer educational attainment.
IS THE COST OF DEBT CAPITAL HIGHER FOR YOUNGER FIRMS?
Authors: Hyytinen Ari , Pajarinen Mika 
Published: January 2007

ABSTRACTNot much is known about the returns to aging (maturing) in the market for small business finance. Using a large panel of closely held micro firms, we document that the cost of debt capital is higher for young firms. The main finding of this paper is that this negative qualitative relation is also obtained when cross‐sectional variation in unobservable creditworthiness of small businesses and within‐firm (i.e., inter‐temporal) variation in their observable creditworthiness are held constant. We control for the former by firm‐specific fixed effects and for the latter by a commercial credit score. We also provide an estimate of the quantitative magnitude of the aging effect, on which both economic theory and earlier empirical research are silent. We find that when a small business ages one year, its cost of debt capital decreases by 1–2 basis points. The effect is neither negligible nor alarmingly large.
SHORT‐TERM CONTRACTS REGULATIONS AND DYNAMIC LABOUR DEMAND: THEORY AND EVIDENCE
Authors: Nunziata Luca , Staffolani Stefano 
Published: January 2007

ABSTRACTWe present a dynamic labour demand model where we evaluate the impact of employment regulations on permanent and temporary employment. We consider three different kinds of regulations, namely firing costs, hiring costs and a constraint on temporary contracts. These regulations differently affect the size and composition of employment. The theoretical results are interpreted and questioned on the basis of empirical evidence on the employment effects of the regulation reforms that occurred in the major European countries in the period 1983–1999. The empirical analysis is based on a new set of time‐varying indicators on permanent employment protection, fixed‐term contracts and temporary agency work regulations. We find evidence in support of the hypothesis that fixed‐term contracts have been effective stepping‐stones to permanent jobs during the period under observation. On the contrary, flexible temporary agency work regulations seem to induce a substitution of permanent with temporary contracts.
FISCAL INDULGENCE IN CENTRAL EUROPE: LOSS OF THE EXTERNAL ANCHOR?
Authors: Berger Helge , Kopits George , Székely István P. 
Published: January 2007

ABSTRACTIn recent years, fiscal performance in Central Europe has steadily deteriorated, in contrast to the improvement in the Baltics. This paper explores the determinants of such differences among countries on the path to European Union (EU) accession. Regression estimates suggest that economic and institutional fundamentals do not provide a full explanation. An alternative explanation lies in the political economy of the accession process, and a game‐theoretic model illustrates why a country with a stronger bargaining position might have an incentive to deviate from convergence to the Maastricht criteria. The model generates alternative fiscal policy regimes – allowing for regime shifts – depending on country characteristics and EU policies.
A NOTE ON NEGATIVE ELECTORAL ADVERTISING: DENIGRATING CHARACTER VS. PORTRAYING EXTREMISM
Authors: Chakrabarti Subhadip 
Published: January 2007

ABSTRACTIn this expository note, we extend the model of Harrington and Hess (1996) by incorporating valence advertising. There is a two‐candidate electoral contest. Candidates inherit a certain position indicating their ideological platform in an unidimensional policy space. They also inherit a certain valence index which is a comprehensive term for personal traits that are desirable to all voters such as integrity. The candidates can subsequently influence these using negative advertising with regard to both ideological and valence factors. We find that when the available resources are sufficiently small and certain reasonable assumptions are fulfilled, the candidate with the higher initial valence index will run a relatively personal campaign while the candidate with the lower initial valence index will run an ideological campaign.
Predicting the effects of exploitation on male‐first sex‐changing fish
Authors: Molloy P. P. , Goodwin N. B. , Côté I. M. , Gage M. J. G. , Reynolds J. D. 
Published: January 2007

AbstractSex change is widespread among tropical marine fishes, many of which are targeted by fisheries. Conservation concerns have been raised that sex‐changing species may be particularly prone to overexploitation by size‐selective fishing. In the case of male‐first sex‐changers, populations may become egg limited if large females are disproportionately killed. However, if males reduce the size at which they change sex in response to higher female mortality, the population may still be sufficiently productive. We develop an age‐based model to explore the effects of fishing on two types of male‐first sex‐changing fish: one with flexibility in size‐at‐sex‐change and one without. These effects were compared with those of non‐sex‐changing populations with similar life‐history and population characteristics. The model predicts that if male‐first sex‐changers cannot respond to elevated female mortality by adjusting their size‐at‐sex‐change, the population will be more prone to recruitment limitation and extinction than non‐sex‐changers. These effects will be amplified as smaller individuals become susceptible to fishing mortality. However, if size‐at‐sex‐change is flexible, sex‐changers may be as resilient to fishing as non‐sex‐changers. Knowledge of a species' size‐at‐sex‐change, and the mechanisms controlling it, should be fundamental to the selection of fisheries conservation strategies.
Monitoring and conservation of critically reduced marine turtle nesting populations: lessons from the Cayman Islands
Authors: Bell C. D. , Solomon J. L. , Blumenthal J. M. , Austin T. J. , Ebanks‐Petrie G. , Broderick A. C. , Godley B. J. 
Published: January 2007

AbstractHistorically, nesting marine turtles were abundant in the Cayman Islands and were an integral part of the economy and culture. Today, nesting of loggerhead turtle Caretta caretta and green turtles Chelonia mydas takes place at very low levels. Hawksbill Eretmochelys imbricata nesting has not been recorded since 1999. We overview highly detailed monitoring data gathered over a 6‐year period allowing insight into the magnitude and spatial and temporal patterns of marine turtle nesting, cost‐effectiveness of monitoring such reduced populations, impacts of development on reproductive success and current threats to the recovery of the population. Nesting is diffuse and widely distributed for both nesting species on Grand and Little Cayman. Modelled nesting detection profiles for Grand Cayman show that in order to maintain data resolution, most sandy coastline must be surveyed throughout each season. However, in Little Cayman it may be possible to reduce effort. Legal take of adults and illegal take of eggs may be significantly impacting the remaining population. Surprisingly, we observed no significant correlation between density of coastal development and clutch density, adult emergence success or hatching success for either species. A significant relationship exists however, between density of coastal development and incidence of misorientation events in loggerhead hatchlings but not in green turtle hatchlings. Effective protection of known nesting habitat and the elimination of exploitation of remaining adults and eggs within the population are critical to its recovery.
Reassembling island ecosystems: the case of Lord Howe Island
Authors: Hutton I. , Parkes J. P. , Sinclair A. R. E. 
Published: January 2007

AbstractExotic species that invade remote islands, usually following human settlement, have had catastrophic effects on native biota. However, on islands it is increasingly feasible to eradicate key exotic species allowing extant native species to recover in situ or to return naturally. The practice of marooning threatened species on islands where the threat is absent, irrespective of whether the threatened species once occurred on the island, is well established. However, less focus has been given to the ‘island’ as the management unit on which to return extirpated species or related surrogates for extinct species. We use the example of Lord Howe Island as a case study to explore options for island restoration should the remaining critical exotic pests (rodents and perhaps owls in this case) be eradicated as planned. Lord Howe Island, in the south‐west Pacific Ocean, is remote, biologically diverse, has a high degree of endemism, and was only discovered by humans in 1778. Consequently, the original and exotic biota and their interactions are all better known than for many islands with a more ancient human history. Two species of plants, nine terrestrial birds, one bat and at least four invertebrates have been lost from the island since 1778. One plant and two invertebrates could be returned as conspecifics. One plant and all the terrestrial birds that are extinct could be replaced by closely related species from elsewhere in the Pacific Ocean. Decisions on replacing extinct species with surrogates should be based on the taxonomic relatedness of the candidates for reintroduction: the same species before subspecies before genera, with functional replacement being a further filter on candidates that are not the same species. In our opinion, taxa with functional equivalence but without taxonomic relatedness would not be acceptable candidates for reintroduction.
Priority areas of intraspecific diversity: Larzac, a global hotspot for facultative paedomorphosis in amphibians
Authors: Denoël M. 
Published: January 2007

AbstractAlthough the designation of biodiversity hotspots is a valuable tool to improve conservation efforts, this is a concept primarily based on species diversity. In consequence, another component of biodiversity, adaptive variation, is often ignored in conservation and to my knowledge no attempt has been made to identify hotspots of remarkable intraspecific patterns. My aim was to focus on the process of facultative paedomorphosis (i.e. the retention of larval traits such as gills in adult variants), a rare developmental pathway. One hundred and seventy‐four ponds were inventoried in Larzac (France) to determine the distribution and abundance of paedomorphic palmate newts Triturus helveticus (Amphibia, Caudata) and to compare these results with the current distribution of paedomorphs in this and other species. During this study, paedomorphic newts were found in 46 ponds, 32 of which were described here for the first time. Seventy‐nine per cent of known paedomorphic populations of this species were found there, whereas this area covers only 0.5% of the distribution area of the species. This represents the highest known density of facultatively paedomorphic populations, all species being considered. Because these populations face a high threat of disappearance, Larzac should be designated as an intraspecific biodiversity hotspot in order to protect adaptive intraspecific variation. Future conservation‐oriented work should focus not only on species distributions but also on phenotypically diverse but spatially localized variation.
Patterns and perceptions of wildlife crop raiding in and around Kerinci Seblat National Park, Sumatra
Authors: Linkie M. , Dinata Y. , Nofrianto A. , Leader‐Williams N. 
Published: January 2007

AbstractCrop raiding can reduce farmers' tolerance towards wildlife. Despite higher human population densities in rural areas, and more rapid conversion of forest to farmland, much less is known about crop raiding in Asia than in Africa. Over 14 months, we identified perceived and actual crop pests, and their patterns of crop raiding from farmland in and around Kerinci Seblat National Park, Sumatra. Farmers named either the wild boar Sus scrofa (80%) or the pig‐tailed macaque Macaca nemestrina (20%) as the two most destructive crop pests. From 5125 crop raids by 11 species of mammal, most raids were indeed made by the wild boar (56%) and the pig‐tailed macaque (19%). For all species combined, temporal crop raiding peaks were positively correlated with periods of high rainfall. Spatially, most crop raids occurred nearest to the forest edge and the local guarding strategies used were ineffective. However, raids by wild boars were more extensive than raids by pig‐tailed macaques, which caused much greater crop damage (73%) than wild boars (26%), contrary to farmers' perceptions. Our research suggests that alternative mitigation strategies need to be trialed over dry and rainy seasons to identify the most effective strategies and that guarding effort should be increased during the rainy seasons and tailored towards specific crop raiding species based on their unique spatial patterns.
Differential glutamate‐dependent and glutamate‐independent adenosine A1 receptor‐mediated modulation of dopamine release in different striatal compartments
Authors: Borycz Janusz , Pereira M. Fátima , Melani Alessia , Rodrigues Ricardo J. , Köfalvi Attila , Panlilio Leigh , Pedata Felicita , Goldberg Steven R. , Cunha Rodrigo A. , Ferré Sergi 
Published: January 2007

AbstractAdenosine and dopamine are two important modulators of glutamatergic neurotransmission in the striatum. However, conflicting reports exist about the role of adenosine and adenosine receptors in the modulation of striatal dopamine release. It has been previously suggested that adenosine A1 receptors localized in glutamatergic nerve terminals indirectly modulate dopamine release, by their ability to modulate glutamate release. In the present study, using in vivo microdialysis, we provide evidence for the existence of a significant glutamate‐independent tonic modulation of dopamine release in most of the analyzed striatal compartments. In the dorsal, but not in the ventral, part of the shell of the nucleus accumbens (NAc), blockade of A1 receptors by local perfusion with the selective A1 receptor antagonist 8‐cyclopentyl‐1,3‐dimethyl‐xanthine or by systemic administration of the non‐selective adenosine antagonist caffeine induced a glutamate‐dependent release of dopamine. On the contrary, A1 receptor blockade induced a glutamate‐independent dopamine release in the core of the NAc and the nucleus caudate–putamen. Furthermore, using immunocytochemical and functional studies in rat striatal synaptosomes, we demonstrate that a fraction of striatal dopaminergic terminals contains adenosine A1 receptors, which directly inhibit dopamine release independently of glutamatergic transmission.