bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonal trends and environmental controls of methane emissions in a rice paddy field in Northern Italy
Authors: Meijide A. , Manca G. , Goded I. , Magliulo V. , di Tommasi P. , Seufert G. , Cescatti A.
Published: December 2011

Abstract. Rice paddy fields are one of the greatest anthropogenic sources of methane (CH4), the third most important greenhouse gas after water vapour and carbon dioxide. In agricultural fields, CH4 is usually measured with the closed chamber technique, resulting in discontinuous series of measurements performed over a limited area, that generally do not provide sufficient information on the short-term variation of the fluxes. On the contrary, aerodynamic techniques have been rarely applied for the measurement of CH4 fluxes in rice paddy fields. The eddy covariance (EC) technique provides integrated continuous measurements over a large area and may increase our understanding of the underlying processes and diurnal and seasonal pattern of CH4 emissions in this ecosystem. For this purpose a Fast Methane Analyzer (Los Gatos Research Ltd.) was installed in a rice paddy field in the Po Valley (Northern Italy). Methane fluxes were measured during the rice growing season with both EC and manually operated closed chambers. Methane fluxes were strongly influenced by the height of the water table, with emissions peaking when it was above 10–12 cm. Soil temperature and the developmental stage of rice plants were also responsible of the seasonal variation on the fluxes. The measured EC fluxes showed a diurnal cycle in the emissions, which was more relevant during the vegetative period, and with CH4 emissions being higher in the late evening, possibly associated with higher water temperature. The comparison between the two measurement techniques shows that greater fluxes are measured with the chambers, especially when higher fluxes are being produced, resulting in 30 % higher seasonal estimations with the chambers than with the EC (41.1 and 31.7 g CH4 m−2 measured with chambers and EC respectively) and even greater differences are found if shorter periods with high chamber sampling frequency are compared. The differences may be a result of the combined effect of overestimation with the chambers and of the possible underestimation by the EC technique.
Volcanic impact on the Atlantic Ocean over the last millennium
Authors: Mignot J. , Khodri M. , Frankignoul C. , Servonnat J.
Published: December 2011

Abstract. The oceanic response to volcanic eruptions over the last 1000 years is investigated with a focus on the North Atlantic Ocean, using a fully coupled AOGCM forced by a realistic time series of volcanic eruptions, total solar irradiance (TSI) and atmospheric greenhouse gases concentration. The model simulates little response to TSI variations but a strong and long-lasting thermal and dynamical oceanic adjustment to volcanic forcing, which is shown to be a function of the time period of the volcanic eruptions. The thermal response consists of a fast tropical cooling due to the radiative forcing by the volcanic eruptions, followed by a penetration of this cooling in the subtropical ocean interior one to five years after the eruption, and propagation of the anomalies toward the high latitudes. The oceanic circulation first adjusts rapidly to low latitude anomalous wind stress induced by the strong cooling. The Atlantic Meridional Overturning Circulation (AMOC) shows a significant intensification 5 to 10 years after the eruptions of the period post-1400 A.D., in response to anomalous atmospheric momentum forcing, and a slight weakening in the following decade. In response to the stronger eruptions occurring between 1100 and 1300, the AMOC shows no intensification and a stronger reduction after 10 years. This study thus stresses the diversity of AMOC response to volcanic eruptions in climate models and discusses possible explanations.
Integral quantification of seasonal soil moisture changes in farmland by cosmic-ray neutrons
Authors: Rivera Villarreyes C. A. , Baroni G. , Oswald S. E.
Published: December 2011

Abstract. Soil moisture at the plot or hill-slope scale is an important link between local vadose zone hydrology and catchment hydrology. However, so far only a few methods are on the way to close this gap between point measurements and remote sensing. One new measurement methodology that could determine integral soil moisture at this scale is the aboveground sensing of cosmic-ray neutrons, more precisely of ground albedo neutrons. The present study performed ground albedo neutron sensing (GANS) at an agricultural field in northern Germany. To test the method it was accompanied by other soil moisture measurements for a summer period with corn crops growing on the field and a later autumn-winter period without crops and a longer period of snow cover. Additionally, meteorological data and aboveground crop biomass were included in the evaluation. Hourly values of ground albedo neutron sensing showed a high statistical variability. Six-hourly values corresponded well with classical soil moisture measurements, after calibration based on one reference dry period and three wet periods of a few days each. Crop biomass seemed to influence the measurements only to minor degree, opposed to snow cover which has a more substantial impact on the measurements. The latter could be quantitatively related to a newly introduced field neutron ratio estimated from neutron counting rates of two energy ranges. Overall, our study outlines a procedure to apply the ground albedo neutron sensing method based on devices now commercially available, without the need for accompanying numerical simulations and suited for longer monitoring periods after initial calibration.
Parameterization of a bucket model for soil-vegetation-atmosphere modeling under seasonal climatic regimes
Authors: Romano N. , Palladino M. , Chirico G. B.
Published: December 2011

Abstract. We investigate the potential impact of accounting for seasonal variations in the climatic forcing and using different methods to parameterize the soil water content at field capacity on the water balance components computed by a bucket model (BM). The single-layer BM of Guswa et al. (2002) is employed, whereas the Richards equation (RE) based Soil Water Atmosphere Plant (SWAP) model is used as a benchmark model. The results are analyzed for two differently-textured soils and for some synthetic runs under real-like seasonal weather conditions, using stochastically-generated daily rainfall data for a period of 100 years. Since transient soil-moisture dynamics and climatic seasonality play a key role in certain zones of the World, such as in Mediterranean land areas, a specific feature of this study is to test the prediction capability of the bucket model under a condition where seasonal variations in rainfall are not in phase with the variations in plant transpiration. Reference is made to a hydrologic year in which we have a rainy period (starting 1 November and lasting 151 days) where vegetation is basically assumed in a dormant stage, followed by a drier and rainless period with a vegetation regrowth phase. Better agreement between BM and RE-SWAP intercomparison results are obtained when BM is parameterized by a field capacity value determined through the drainage method proposed by Romano and Santini (2002). Depending on the vegetation regrowth or dormant seasons, rainfall variability within a season results in transpiration regimes and soil moisture fluctuations with distinctive features. During the vegetation regrowth season, transpiration exerts a key control on soil water budget with respect to rainfall. During the dormant season of vegetation, the precipitation regime becomes an important climate forcing. Simulations also highlight the occurrence of bimodality in the probability distribution of soil moisture during the season when plants are dormant, reflecting that soil, it being of coarser or finer texture, can be preferentially in either wetter or drier states over this period.
Satellite remote sensing of water turbidity in Alqueva reservoir and implications on lake modelling
Authors: Potes M. , Costa M. J. , Salgado R.
Published: December 2011

Abstract. The quality control and monitoring of surface freshwaters is crucial, since some of these water masses constitute essential renewable water resources for a variety of purposes. In addition, changes in the surface water composition may affect physical properties of the lake water, such as temperature, which in turn may impact exchanges with the lower troposphere. The use of satellite remote sensing to estimate water turbidity of Alqueva reservoir, located in the south of Portugal, is explored. A validation study of the satellite derived water leaving spectral reflectance is firstly presented, using data taken during three field campaigns carried out during 2010 and early 2011. Secondly an empirical algorithm to estimate lake water surface turbidity from the combination of in situ and satellite measurements is proposed. The importance of water turbidity on the surface energy balance is tested in the form of a lake model sensitivity study to the water extinction coefficient (estimated from turbidity), showing that this is an important parameters tuning the lake surface temperature.
Using comparative analysis to teach about the nature of nonstationarity in future flood predictions
Authors: Shaw S. B. , Walter M. T.
Published: December 2011

Abstract. Comparative analysis has been a little used approach to the teaching of hydrology. Instead, hydrology is often taught by introducing fundamental principles with the assumption that they are sufficiently universal to apply across most any hydrologic system. In this paper, we illustrate the value of using comparative analysis to enhance students' insights into the degree and predictability of future non-stationarity in flood frequency analysis. Traditionally, flood frequency analysis is taught from a statistical perspective that can offer limited means of understanding the nature of non-stationarity. By visually comparing graphics of mean daily flows and annual peak discharges (plotted against Julian day) for watersheds in a variety of locales, distinct differences in the timing and nature of flooding in different regions of the US becomes readily apparent. Such differences highlight the dominant hydroclimatological drivers of different watersheds. When linked with information on the predictability of hydroclimatic drivers (hurricanes, atmospheric rivers, snowpack melt, convective events) in a changing climate, such comparative analysis provides students with an improved physical understanding of flood processes and a stronger foundation on which to make judgments about how to modify statistical techniques for making predictions in a changing climate. We envision that such comparative analyses could be incorporated into a number of other traditional hydrologic topics.
The effect of stochastic perturbations on plankton transport by internal solitary waves
Authors: Stastna M. , Poulin F. J. , Subich C. , Mecking J. V.
Published: December 2011

Abstract. Internal solitary and solitary-like waves are a commonly observed feature of density stratified natural waters, including lakes and the coastal ocean. Since such waves induce significant currents throughout the water column they can be responsible for significant transport of both passive and swimming biota. We consider simple models of moving zooplankton based on the Langevin equation. The small amplitude randomness significantly alters the nature of particle motion. In particular, passage through the wave leads to strongly non Gaussian particle distributions. When the plankton swims to return to its equilibrium photic level, a steady state that balances randomness, swimming and wave-induced motions is possible. We discuss possible implications of this steady state for organisms that feed on plankton.
Effect of glacial-interglacial sea-level changes on the displacement and stress field in the forearc and along the plate interface of subduction zones
Authors: Li T. , Hampel A.
Published: December 2011

Abstract. Combined seismological, space-geodetic and numerical studies have shown that the seismicity at subduction zones may be modulated by tides and glacier fluctuations on timescales of 1–100 a, because these changes in loads on Earth's surface are able to alter the stress field in the upper plate and along the plate interface. Here we use a two-dimensional finite-element model of a subduction zone to investigate how glacial-interglacial sea-level changes affect the forearc region and the plate interface. The model results show that a sea-level fall by 125 m over 100 ka causes up to 0.7 m of vertical displacement, with the maximum uplift occurring between the trench and the coast. The uplift signal induced by the sea-level fall decreases to zero ~20 km landward of the coastline. A subsequent sea-level rise by 125 m over 20 ka causes subsidence, which is again most pronounced in the submarine part of the forearc. The sea-level changes cause horizontal displacements of up to 0.12 m, which are directed seaward during sea-level fall and landward during sea-level rise. With respect to the stress field, the sea-level changes lead to variations in the vertical stress and the shear stress of up to 1.23 MPa and 0.4 MPa, respectively. The shear stress variations are highest beneath the coast, i.e. in the area where the sea-level changes cause the strongest flexure. The resulting Coulomb stress changes on the plate interface are of the order of 0.2–0.5 MPa and indicate that earthquakes are promoted during sea-level fall and delayed during sea-level rise. Our findings imply that eustatic sea-level changes during glacial-interglacial periods may have induced displacements and stress changes that were large enough to affect the seismic cycle of subduction thrusts.
Brief Communication: Greenland's shrinking ice cover: ″fast times″ but not that fast
Authors: Kargel J. S. , Ahlstrøm A. P. , Alley R. B. , Bamber J. L. , Benham T. J. , Box J. E. , Chen C. , Christoffersen P. , Citterio M. , Cogley J. G. , Jiskoot H. , Leonard G. J. , Morin P. , Scambos T. , Sheldon T. , Willis I.
Published: December 2011

Abstract. A map of Greenland in the 13th edition (2011) of the Times Comprehensive Atlas of the World made headlines because the publisher's media release mistakenly stated that the permanent ice cover had shrunk 15 % since the previous 10th edition (1999) revision. The claimed shrinkage was immediately challenged by glaciologists, then retracted by the publisher. Here we show: (1) accurate maps of ice extent based on 1978/1987 aerial surveys and recent MODIS imaging; and (2) shrinkage at 0.019 % a−1 in ∼ 50 000 km2 of ice in a part of east Greenland that is shown as ice-free in the Times Atlas.
Correcting for Selectivity Bias in the Estimation of Tourist Spending Surveys
Authors: Yang Sheng-Ping , Ryerson Annette
Published: December 2011

Focusing on a small tourist destination, this study investigates how the conventional design and administration of surveys of tourism expenditure can result in selectivity bias. The bias arises from the assumption that day and overnight visitors possess identical spending patterns, and thus can be surveyed with the same instrument. To remove such a bias, the authors apply a two-stage procedure to distinguish the expenditure decisions made by day visitors from those made by overnight visitors. The results suggest that conventional surveys potentially underestimate expenditures by day visitors and overestimate expenditures by overnight visitors.
Influence of Uncertain Demand on Product Variety: Evidence from the International Tourist Hotel Industry in Taiwan
Authors: Chen Chiang-Ming , Yeh Chia-Yu , Hu Jin-Li
Published: December 2011

Hotels provide many different types of rooms in terms of capacity as well as quality to diversify their products. This paper examines the relationship of uncertain demand and product variety by using monthly operation data from international tourist hotels in Taiwan during 2007–2009. First, the authors apply the two-stage least squares (2SLS) and random-coefficients models to estimate the demand function in Taiwan's international tourist hotel industry. They then examine the relationship between uncertain demand and product variety. The empirical results indicate that the market's uncertain demand significantly induces the hotels to expand their product variety.
Research Note: Tourism as a Factor of Growth – the Case of Brazil
Authors: Brida Juan Gabriel , Punzo Lionello F. , Risso Wiston Adrián
Published: December 2011

International tourism is recognized to contribute to long-run growth through a whole list of diverse channels. This belief that tourism can cause long-run growth is known in the literature as the ‘tourism-led growth hypothesis’. This case study of Brazil can be taken as a specific test for such a hypothesis. In the paper, two different econometric methodologies are applied to two distinct data sets, showing that the results are independent of either data or methodology. On the one hand, annual data from 1965 to 2007 for Brazil as a whole are used for a cointegration analysis to look for the existence of a long-run relationship among variables of economic growth, international tourism earnings and the real exchange rate. On the other hand, high-quality data for the 27 Brazilian states, though for a shorter period (from 1990 to 2005), enable the use of the dynamic panel data model proposed by Arellano and Bond (1991). The authors show that the long-run elasticities between real per capita GDP with respect to tourism receipts and the real rate of exchange are 0.13 and 0.30, respectively. Finally, they compare their results with those of similar studies.
Research Note: Tourism and Economic Growth in Latin American Countries – Further Empirical Evidence
Authors: Fayissa Bichaka , Nsiah Christian , Tadesse Bedassa
Published: December 2011

Using panel data that span from 1990 to 2005, the authors investigate the impact of tourism on the economic growth of 18 heterogeneous Latin American countries within the framework of the conventional neoclassical growth model. Results from the empirical models show that revenues from the tourism industry contribute positively to both the current level and the growth rate of the per capita GDP of the countries in the region, as do investments in physical and human capital. The findings imply that Latin American economies may enhance their economic growth in the short run by strengthening their tourism industries strategically, while not neglecting the traditional sources of economic growth.
The Economic Impact of Cultural Events: The Umbria Jazz Music Festival
Authors: Bracalente Bruno , Chirieleison Cecilia , Cossignani Massimo , Ferrucci Luca , Gigliotti Marina , Ranalli M. Giovanna
Published: December 2011

This paper assesses the economic impact of a cultural event on a local economy. The event analysed is the Umbria Jazz music festival, which is held annually in July in the city of Perugia in Italy. The relevance of this case study concerns the methodological problems involved in estimating the number of visitors attracted by an event characterized by numerous free concerts. In addition, through the choice of the components of expenditure and the impact analysis model, the proposed approach represents an advanced synthesis of the paths which have been developing in the literature.
New Black Holes Solutions in a Modified Gravity
Authors: Daouda M. Hamani , Rodrigues Manuel E. , Houndjo M. J. S.
Published: December 2011

We present some basic concepts of a theory of modified gravity, inspired by the gauge
theories, where the commutator algebra of covariant derivative gives us an added term with respect to the General Relativity, which represents the interaction of gravity with a substratum. New spherically symmetric solutions of this theory are obtained and can be viewed as solutions that reproduce the mass, the charge, the cosmological constant, and the Rindler acceleration, without coupling with the matter content, that is, in the vacuum.
Recent approaches to model the risk of storm and fire
Authors: Hanewinkel Marc , Peltola H. , Soares P. , González-Olabarria J. R.
Published: December 2011

The aim of this paper is to discuss the different recently developed empirical and mechanistic modelling approaches for assessing the risk of wind and fire damage to forests. Additionally the work will explore possible ways to integrate these approaches, including feedback mechanisms, into growth and yield models and decision support tools used in forestry. The integration of mechanistic and empirical storm risk models, as well as an empirical/mechanistic fire risk model into growth simulators is demonstrated and future challenges and options for risk modelling and for creating complex decision support tools, including growth simulators, meteorological components and risk modules, are discussed.
Former agriculture impacts on properties of Norway spruce forest
Authors: Kacalek D. , Dusek D. , Novak J. , Slodicak M. , Bartos J. , Cernohous V. , Balcar V.
Published: December 2011

Forest floor is considered a major feature distinguishing forest from agricultural soils. Forest floor develops as forest stands grow and is composed of more or less altered plant-tissue biomass accumulated on the soil surface. Our study’s aim was to find whether properties of both the organic layers and mineral soil differ according to the land-use history of the sites compared. Each site included an afforested area of immature 50-year-old spruce forest (AFF) on formerly agricultural land plus an adjacent area of old-growth 100-year-old spruce stand (FOR). The localities are situated at altitudes ranging between 600 and 850 metres above sea level. From the results of our study it can be concluded that both forest floor and mineral soil had higher pH and Ca concentration at formerly agricultural sites. C/N ratio is significantly lower in afforested soil. First-generation humus was significantly higher in phosphorus.
Growth, soil properties and foliage chemical analysis comparison
Authors: Nunes L. , Coutinho J. , Nunes L.F. , Castro Rego F. , Lopes D.
Published: December 2011

Ecosystems with mixed species compared to the ones with pure compositions provide a broader range of options in the fields of biodiversity, conservation, protection and restoration. Industrial plantations in Portugal are mostly monocultures with the predominance of coniferous forests, so the introduction of broadleaves could be important for the biodiversity and sustainability of Portuguese forests. This study aims to present and discuss field data from pure and mixed-species plantations of European chestnut (Castanea sativa Mill.) and douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] with different intercropping densities in a total of 5 treatments with two replicate blocks. In respect to growth, the results showed significant difference (P < 0.05, Scheffe) between treatments for survival and basal area. Diameter breast height (DBH), total and top height of the individual Castanea tree was positively affected by the presence of Pseudotsuga. In general, soil properties results showed a higher fertility for mixed treatments compared with pure ones. Statistically differences (P < 0.05, Scheffe) were observed in pH, P, Mn and in the exchangeable acidity. Results for foliar analysis in N, P, Ca and K concentrations are higher for mixed treatments. The obtained results from this study indicate that mixed plantations have a positive effect in the productivity of the Castanea.
Insect biodiversity reduction of pinewoods in southern Greece caused by the pine scale (Marchalina hellenica)
Authors: Petrakis Panos V. , Spanos Kostas , Feest Alan
Published: December 2011

This paper deals with the impact of the pine scale (Marchalina hellenica Gennadius, Hemiptera, Sternorrhyncha, Margarodidae) on the insect biodiversity of pinewoods in Attica, Greece. The comparison of biodiversities was done by estimating the biodiversity by the Ewens-Caswell V statistic in a set of nine sites each containing two linetransects. Transects pairs went through free and infested pinewoods from the pine scale and each one had several tenth hectare plots on both sides. The ecosystem temperature (= disorder) of the sites was computed and found high, together with the idiosyncratic temperatures (= susceptibility to extinction) of the 158 species in order to detect local extinctions. The indicator values of insect species were computed on the basis of the relative cover of each plant species. The main findings of this study are (1) the reduction of insect species biodiversity because of the introduction of the pine scale, (2) the moderate increase of disorder in pine scale infested sites,(3) many insect species can characterize site groups but none of them can distinguish infested from pine scale free sites. The introduction of pine scale in pinewoods disturbs their insect fauna before its influence to the floristic composition and the associated vegetation structure appears. The causes behind this reduction of biodiversity and the anthropogenic influences are discussed.
Modelling the probability of lightning-induced forest fire occurrence in the province of León (NW Spain)
Authors: Castedo-Dorado Fernando , Rodríguez-Pérez José Ramón , Marcos-Menéndez José Luis , Álvarez-Taboada Mª Flor
Published: December 2011

Spatial relationships between lightning-induced forest fires and topography, vegetation, climate and lightning characteristics were analyzed in the province of León (NW Spain). The study was based on reported lightning-induced forest fires in the period 2002-2007. A statistical model based on logistic regression was developed to estimate the probability of occurrence of a lightning-induced fire in a 3 x 3 km grid. The importance of accurate location of the ignition point was also investigated in order to evaluate the sensitivity of the model developed to uncertainty of the location. The model developed with accurate ignition point data showed a better predictive ability than the model constructed with all the ignition points available. The former model was therefore selected for long-term prediction of the occurrence of lightning-induced fires in the province. According to this model, the probability of a forest stand being affected by lightning-induced fire increased with decreasing altitude, and when there was a high proportion of coniferous species in the stand, a high percentage of lightning strikes in forest areas and a high number of dry storm days in the area. Although the model has not been validated, the results can be considered spatially robust because it shows good classification ability and the predicted spatial probability distribution is consistent with the observed historical fire records. The model will be useful in the spatially explicit assessment of fire risk, the planning and coordination of regional efforts to identify areas at greatest risk, and in designing long-term wildfire management strategies.
Regeneration of potential laurel forest under a native canopy vs. exotic canopy, Tenerife (Canary Islands)
Authors: Arevalo Jose Ramon , Delgado J D , Fernandez-Palacios J M
Published: December 2011

Exotic tree monocultures adversely affect native ecosystems through competition and alteration of nutrient availability and dynamics. However, there is evidence of some tree plantations facilitating a more rapid recovery of the native plant communities by providing shelter-wood for the plants below and attracting seed dispersers. The results either way are specific to the plantation species and to the native forest type. In this study we analysed the differences in regeneration of native woody species in two stands of exotic species, Pinus radiata and Eucaliptus globulus, occupying native laurel forest ground, and also examined the regeneration in adjacent native forest stands to reveal if the effects of the exotic plants are negatively affecting the recovery of the native plant community. The native stands differed from the exotic stands in tree species richness, basal area and density. However, regeneration was very similar between alien and native stands, and advanced regeneration can be inferred from the results. Differences were quantitatively important, but species composition of the regenerating community was similar. Also, these planted areas have recovered their canopy very fast as long as P. radiata and E. globulus have rapid growth in comparison with native laurel forest species. These rapid recover of the canopy has prevented deeper erosion damage and has to some extent facilitated the regeneration of native species. The results indicate that a progressive elimination of the exotic stands would favor the establishment and growth of native species. The role of some exotic tree species in the restoration of laurel forest areas should not be systematically regarded as negative.
Soil moisture spatio-temporal behavior of Pinus pinaster stands on sandy flatlands of central Spain.
Authors: Gómez Sanz Valentin , Garcia-Viñas J I
Published: December 2011

Pinus pinaster stands in the center of the Iberian Peninsula frequently grow in a unique hydrological system characterized by a variable groundwater table near the soil surface and highly permeable soils (arenosols). Over the last few decades, this superficial aquifer has been overused as a water resource, especially for irrigated crops. Overuse has reached a critical level and has caused various environmental impacts and a water sustainability crisis wherein rainfall variability does not allow for a sufficient level of aquifer recharge by natural means. Within this changing scenario, soil water significantly affects the spatio-temporal ecological response, necessitating more extensive characterization of the complex soil-tree water relationship. The primary goal of the present work was to evaluate the influence of root zone soil moisture on the observed spatial response of Pinus pinaster stands. Volumetric soil moisture content was measured at eleven forest sites, using time-domain reflectometry (TDR), over a two-year observation period. The results demonstrate that the combined effect of groundwater table proximity and dune morphology associated with this area are the main factors driving very different water availability conditions among the monitored hydrological response units, which modulate maritime pine installation and development. Topographically lower areas are more heterogeneous in terms of soil moisture behavior. In these areas, the conifer forests that are connected to the water table may be the most sensitive to land use changes within current environmental change scenarios. Consequently, in these pine ecosystems, the combined influences of geomorphology and water table proximity on variations in root zone soil moisture are essential and must be considered to develop adequate adaptive management models.
Cross transferability of SSRs to five species of Araucariaceae: a useful tool for population genetic studies in Araucaria araucana
Authors: Moreno Angela Carolina , Marchelli Paula , Vendramin Giovanni Giuseppe , Gallo Leonardo Ariel
Published: December 2011

Cross-species amplification of microsatellites is a common procedure to obtain suitable markers to be used in population genetic studies. Primers designed for one (source) species are used to amplify homologous loci in related (target) species. It is expected that phylogenetically close species will share a higher proportion of markers, and genetic distance could be a useful parameter to predict successful transferability between different taxonomic groups. We analyzed twenty-two primer pairs developed for Araucaria angustifolia (Bertol.) Kuntze in five target species of the Araucariaceae family. The results were summarized in vectors of presence and absence of bands and compared through the Jaccard similarity index. Using the sequences of eight published genes, genetic distances between pairs of species were estimated and related to transferability rate using Pearson correlations. Successful transfer rate ranged from 31.8 to 77.3%, being these among the highest reported for plants. The highest transfer rate was observed between the South American species. The transferability was confirmed sequencing seven fragments amplified in A. araucana (Molina) K. Koch, and using the best five to estimate genetic diversity parameters in a natural population of this Andean coniferous.
Genetic redundancy among durum wheat accessions as assessed by SSRs and endosperm proteins
Authors: Ruiz M. , Aguiriano E. , Giraldo P. , Carrillo J. M.
Published: December 2011

Reducing duplication in ex-situ collections is complicated and requires good quality genetic markers. This study was conducted to assess the value of endosperm proteins and SSRs for validation of potential duplicates and monitoring intra-accession variability. Fifty durum wheat (Triticum turgidum ssp. durum) accessions grouped in 23 potential duplicates, and previously characterised for 30 agro-morphological traits, were analysed for gliadin and high molecular weight glutenin (HMWG) subunit alleles, total protein, and 24 SSRs, covering a wide genome area. Similarity and dissimilarity matrices were generated based on protein and SSRs alleles. For heterogeneous accessions at gliadins the percent pattern homology (PH) between gliadin patterns and the Nei’s coefficient of genetic identity (I) were computed. Eighteen duplicates identical for proteins showed none or less than 3 unshared SSRs alleles. For heterogeneous accessions PH and I values lower than 80 identified clearly off-types with more than 3 SSRs unshared. Only those biotypes differing in no more than one protein-coding locus were confirmed with SSRs. A good concordance among proteins, morphological traits, and SSR were detected. However, the discrepancy in similarity detected in some cases showed that it is advisable to evaluate redundancy through distinct approaches. The analysis in proteins together with SSRs data are very useful to identify duplicates, biotypes, close related genotypes, and contaminations.
Review. Use of psychrometers in field measurements of plant material: accuracy and handling difficulties
Authors: Martinez E. M. , Cancela J. J. , Cuesta T. S. , Neira X. X.
Published: December 2011

The determination of leaf water potential is useful in the establishment of irrigation guidelines for agricultural crop management practices and requires the use of various methods, among which thermocouple psychrometers (TCP). TCP have been widely used for this purpose. However, the psychrometric technique is complex and difficult to understand and the instrumentation required is difficult to handle. For this reason, a profound knowledge of the different aspects involved in the technique —which have not been clearly explained in the literature— is required. This paper reviews a number of research areas of TCP and focuses on three very specific fields: a) main applications of phsychrometry in field studies; b) determination of the measurement accuracy of psychrometric equipment, accuracy per se and accuracy tested against alternative methods; c) main errors and handling difficulties of TCP in the field. Research in these areas provides an updated overview of TCP as a method for determining water relations in plant material that will contribute criteria to select the most suitable technique according to the type of plant material and the purpose of the research and will highlight the types of instruments, accuracies and errors that have detrimental effects on measurements.
A new species of Seticeros from Costa Rica (Coleoptera, Cerambycidae, Prioninae)
Authors: Ramirez Campos R. , Esteban Duran J. R. , Santos-Silva A.
Published: December 2011

A new species of Seticeros Perger & Santos-Silva, 2010 (Prioninae: Callipogonini) from San Isidro del General, San José, Costa Rica is described and illustrated. A key to the species of Seticeros is added.
Optimization of macroelement contents in raspberry leaves by liming in an extremely acid soil
Authors: Sikiric B. , Cakmak D. , Saljnikov E. , Mrvic V. , Jakovljevic M. , Stajkovic O. , Bogdanovic D.
Published: December 2011

Raspberries thrive best in an acid soil. However, if the soil pH is lower than 5.6, lime application is necessary. In this study the effects of lime and dolomite application in combination with NPK 15:15:15 fertilizer (600 kg ha–1) on the macroelement contents (N, P, K, Ca, and Mg) in an extremely acid soil (pH 4.35) and raspberry leaves were evaluated during a three-year period. Optimal pH value for raspberry cultivation (5.84) was achieved with the application of 9 t ha–1 of lime. The mineral nitrogen (NH4+NO3)-N content and P content in the soil after liming increased significantly, but P concentration stayed below the optimal values. Additionally, no changes were noted in K concentration in the soil. The Ca concentration increased significantly in all treatments, while the Mg content increased significantly only in the treatment with dolomite. The N content in the raspberry leaves increased, but K content decreased after liming. There was no change in P content in the leaves affected by liming. Lime increased Ca content in the leaves above the optimal values, while it did not affect the initially optimal Mg content in the leaves. After liming and NPK fertilization, the concentrations of N, P and K in the leaves were still below the optimal values, indicating a need for the combination of higher rates of fertilizer with lime in raspberry cultivation in very acid soils.
Genetic effects on morphological and yield traits in cotton (Gossypium hirsutum L.)
Authors: Khan N. U. , Hassan G.
Published: December 2011

The nature and magnitude of genetic effects on morpho-yield traits were studied in a 6 × 6 F1 and F2 diallel cross inupland cotton. An additive-dominance model was adequate for most of the traits except plant height and seed cottonyield, where the model was partially adequate. Genetic parameters were estimated following Hayman’s and Mather’smodel. Additive effects controlled lint percentage and monopodia in both generations, and plant height and sympodia in F2. Non-additive inheritance with over-dominance controlled yield in both generations, and plant height and sympodia in F1. Most traits presented an unequal proportion of positive (U) and negative (V) alleles in the loci (H2<H1)and an asymmetrical distribution of genes in the parents (H2/4H1 < 0.25 and F different to zero). The value of H2/4H1was lower than maximum value (0.25) for all of traits, which arises when U = V = 0.5 over all loci. The proportion4DH1+F/4DH1–F) confirmed by half of the traits that dominant alleles were in excess as compared to recessive alleles. Dominance effects (h2) for most of the traits suggested that substantial contribution of dominance was not due to heterogeneity of loci in these parameters. Broad and narrow sense heritabilities were high for most of the traits.Correlation coefficient between the Wr + Vr and mid parental (y) indicated that dominant genes were responsible forincreased sympodia, lint % and yield, and recessive genes increased monopodia and plant height. Genetic gain wasencouraging for most traits. Cultivar CIM-1100 was identified by genetic advancement as a promising parental cultivarto cross combinations.
Short communication. Toxicity of emamectin benzoate to adults of Nesidiocoris tenuis Reuter, Macrolophus pygmaeus (Rambur) (Heteroptera, Miridae) and Diglyphus isaea Walker (Hymenoptera, Eulophidae) on tomato plants. Semi-field studies
Authors: Lopez J. A. , Amor F. , Bengochea P. , Medina P. , Budia F. , Viñuela E.
Published: December 2011

Whiteflies, the tomato borer and leafminers are among the major pests of greenhouse tomatoes in Spain. Macrolophuspygmaeus (Heteroptera, Miridae) and Nesidiocoris tenuis are polyphagous predators of whiteflies, the tomato borer and other pests. Diglyphus isaea (Hymenoptera, Eulophidae) is an ectoparasite of leafminers. These three natural enemies are commonly released in the commercial horticultural  greenhouses of south-eastern Spain. Emamectin benzoate is a new semi-synthetic derivative of the avermectin B1 developed for Lepidoptera pest control in vegetable crops, with requested inclusion in annex I of the EU directive 91/414/EEC. As for any new insecticide that is being introduced for its use in protected tomato, it is critical to understand the level of compatibility of emamectin in frontof those major biological control agents. Potted tomato plants kept in a greenhouse were sprayed with the highestrecommended field rate of emamectin benzoate (14.25 mg L–1), and the toxicity of fresh and 7-day-old residues toadults of the three biological control agents were studied to ascertain their compatibility. The results demonstrated thecompatibility of both fresh and 7-day-old residues with the three species of natural enemies.
Aquaponics: integrating fish feeding rates and ion waste production for strawberry hydroponics
Authors: Villarroel M. , Alvariño J. M. R. , Duran J. M.
Published: December 2011

Aquaponics is the science of integrating intensive fish aquaculture with plant production in recirculating water systems. Although ion waste production by f ish cannot satisfy all plant requirements, less is known about the relationship between total feed provided for f ish and the production of milliequivalents (mEq) of different macronutrients for plants, especially for nutrient flow hydroponics used for strawberry production in Spain. That knowledge is essential to consider the amount of macronutrients available in aquaculture systems so that farmers can estimate how much nutrient needs to be supplemented in the waste water from fish, to produce viable plant growth. In the present experiment, tilapia (Oreochromis niloticus L.) were grown in a small-scale recirculating system at two different densities while growth and feed consumption were noted every week for five weeks. At the same time points, water samples were taken to measure pH, EC25, HCO3–, Cl–, NH4+, NO2–, NO3–, H2PO4–, SO42–, Na+, K+, Ca2+ and Mg2+ build up. The total increase in mEq of each ion per kg of feed provided to the fish was highest for NO3-, followed, in decreasing order, by Ca2+, H2PO4–, K+, Mg2+ and SO42–. The total amount of feed required per mEq ranged from 1.61- 13.1 kg for the four most abundant ions (NO3–, Ca2+, H2PO4– and K+) at a density of 2 kg fish m–3, suggesting that it would be rather easy to maintain small populations of fish to reduce the cost of hydroponic solution supplementation for strawberries.
Molecular and morphological analyses of date palm (Phoenix dactylifera L.) subpopulations in southern Tunisia
Authors: Hamza H. , Elbekkay M. , Ben Abederrahim M. A. , Ferchichi Ali A.
Published: December 2011

Phoenix dactylifera L. is widely distributed and performs an important socioeconomic role in the south of Tunisia.The objective of this work was to evaluate different methods of estimating the diversity and genetic structure of Tunisiandate palm subpopulations. Nine morphological traits and five SSR loci were used to study morphological and genetic diversity. Correlations between phenotypic and genetic distances were assessed. Analyses of variance of the morphological data reveal significant differences among subpopulations for all traits measured. The Mantel test shows that morphological variation is correlated with fruit maturity period (r = 0.161; p = 0.020). Analysis of molecular variance reveals significant genetic variation among fruit-consistency subpopulations (p < 0.05) and the Mantel test emphasises a correlation between genetic distance and fruit consistency (r = 0.110; p = 0.029). This information will be useful for germplasm collection, for conservation and for various date palm culture programmes in the Tunisian continental oases.
Evaluating models for the estimation of furrow irrigation infiltration and roughness
Authors: Ramezani Etedali H. , Ebrahimian H. , Abbasi F. , Liaghat A.
Published: December 2011

Several methods have been proposed for estimating infiltration and roughness parameters in surface irrigation using mathematical models. The EVALUE, SIPAR_ID, and INFILT models were used in this work. The EVALUE modeluses a direct solution procedure, whereas the other two models are based on the inverse solution approach. The objective of this study is to evaluate the capacity of these models to estimate the Kostiakov infiltration parameters and the Manning roughness coefficient in furrow irrigation. Twelve data sets corresponding to blocked-end and free drainingfurrows were used in this work. Using the estimated  parameters and the SIRMOD irrigation simulation software, the total infiltrated volume and recession time were predicted to evaluate the accuracy of the mathematical models. TheEVALUE and SIPAR_ID models provided the best performance, with EVALUE performing better than SIPAR_ID for estimating the Manning roughness coefficient. The INFILT model provided lower accuracy in cut-back irrigation than in standard irrigation. The performance of SIPAR_ID and INFILT in blocked-end and free draining furrows was similar.
Citrus-orchard ground harbours a diverse, well-established and abundant ground-dwelling spider fauna
Authors: Monzó C. , Mollá O. , Vanaclocha P. , Montón H. , Melic A. , Castañera P. , Urbaneja A.
Published: December 2011

Ground-dwelling spider assemblages comprise one of the most representative predatory groups to be found in manycrops. There is some evidence of the role that ground-dwelling spiders play in controlling certain citrus pests; however, thereare almost no studies about the abundance and composition of this predatory group in citrus orchards. A three-year surveyconducted using pitfall traps in three citrus orchards in Eastern Spain yielded more than five-thousand ground-dwellingspiders belonging to more than 50 species and 20 families. Wandering families such as Lycosidae, Gnaphosidae andZodariidaewere the most numerous in terms of captures. The generalist predator Pardosa cribata Simon (Araneae: Lycosidae) was the most common species, representing a quarter of all captures, followed by Zodarion cesari Pekar. (Araneae: Zodariidae) and Trachyzelotes fuscipes (Koch) (Araneae: Gnaphosidae). Spiders were active throughout the year with a peak population in summer. The species abundance data for the three spider assemblages sampled fitted a log normal statistical model which is consistent with a well-established community. The presence of a cover crop provided higher abundance of alternative prey and consequently higher abundance and diversity of ground-dwelling spiders. This work demonstrates that the citrus-orchard ground harbours a diverse and abundant ground-dwelling spider fauna, which is also active throughout the year. A challenge for future studies will be to establish conservation management strategies for these predators, that will improve biological control of those citrus pests that inhabit or spend part of their life cycle on the orchard floor.