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991.
This paper presents a general, process-based mass balance model (CoastMab) for total phosphorus (TP) in defined coastal areas
(at the ecosystem scale). The model is based on ordinary differential equations and calculates inflow, outflow and internal
fluxes on a monthly basis. It consists of four compartments: surface water, deep water, erosion/transportation areas for fine
sediments and accumulation areas for fine sediments. The separation between surface water and deep water is not done based
on water temperature, but on sedimentological criteria instead (from the theoretical wave base). There are algorithms for
all major internal TP fluxes (sedimentation, resuspension, diffusion, mixing and burial). Validations were performed using
data from 21 different Baltic coastal areas. The results show that the model predicts monthly TP in water and chlorophyll a very well (generally within the uncertainty bands of the empirical data). The model has also been put through sensitivity
tests, which show that the most important factor regulating the predictions of the model is generally the TP concentration
in the sea beyond the coast. The model is simple to apply, since all driving variables may be accessed from maps or monitoring
programs. The driving variables include coastal area, section area (between the defined coastal area and the adjacent sea),
mean and maximum depths, latitude (used to predict water temperatures, stratification and mixing), salinity and TP concentration
in the sea. Many of the model structures are general and could be used for areas other than those included in this study,
e.g., for open coasts, estuaries or tidal coasts, as well as for other substances than phosphorus. 相似文献
992.
Ljiljana Vapa Mihajla Djan Dragana Obreht Milos Beukovic Milan Vapa 《European Journal of Wildlife Research》2007,53(1):52-54
The pheasant breeds are widely used for restocking of natural populations depleted by hunting. The pheasant population number
decline was detected during the 1970s in many hunting areas of Europe. One of its possible reasons might be the loss of adaptability
in populations originating from breeding stations, which was caused by inbreeding depression. The aim of this paper was the
analysis of genetic variability in pheasant populations from three breeding stations in Vojvodina province (Serbia) by means
of allozyme diversity detection. The allozyme variability analysis of pheasants from all three breeding stations revealed
polymorphisms at nine loci: Ldh-1, Mor-1, Mor-2, Es-1, Mod-2, Pgd, Gpi-2, Odh, and Sod. The analysis of individuals from three different breeding stations showed mean values of observed heterozygosity of H
o=0.137, polymorphism P
95%=30%, and H/P ratio H/P=0.430, which indicate a normal level of genetic variability for bird populations. Comparative analysis of three pheasant
populations showed a high level of interpopulation differentiation. 相似文献
993.
Vincent J. Tepedino Diane Gail Alston Brosi A. Bradley Trent R. Toler Terry L. Griswold 《Biodiversity and Conservation》2007,16(11):3083-3094
Capitol Reef National Park in central Utah, USA surrounds 22 managed fruit orchards started over a century ago by Mormon pioneers.
Honey bees are imported for pollination, although the area in which the Park is embedded has over 700 species of native bees,
many of which are potential orchard pollinators. We studied the visitation of native bees to apple, pear, apricot, and sweet
cherry over 2 years. Thirty species of bees visited the flowers but, except for pear flowers, most were uncommon compared
to honey bees. Evidence that honey bees prevented native bees from foraging on orchard crop flowers was equivocal: generally,
honey bee and native bee visitation rates to the flowers were not negatively correlated, nor were native bee visitation rates
positively correlated with distance of orchards from honey bee hives. Conversely, competition was tentatively suggested by
much larger numbers of honey bees than natives on the flowers of apples, apricots and cherry; and by the large increase of
native bees on pears, where honey bee numbers were low. At least one-third of the native bee species visiting the flowers
are potential pollinators, including cavity-nesting species such as Osmia lignaria propinqua, currently managed for small orchard pollination in the US, plus several fossorial species, including one rosaceous flower
specialist (Andrena milwaukiensis). We suggest that gradual withdrawal of honey bees from the Park would help conserve native bee populations without decreasing
orchard crop productivity, and would serve as a demonstration of the commercial value of native pollinators. 相似文献
994.
Parthasarathy NJ Srikumar R Manikandan S Narayanan GS Devi RS 《Cell biology and toxicology》2007,23(3):177-187
Our previous studies revealed that methanol intoxication significantly altered the non-specific immune functions in albino rats. The present investigation focuses on the effect of methanol on certain specific immune functions of cell mediated immunity such as footpad thickness, leukocyte migration inhibition test (LMI) and antibody levels. In addition, serum interleukins (IL-2, IL-4, TNF-alpha and IFN-gamma), and splenic lymphocyte subsets were measured after an immune challenge. The specific immune function tests were carried out in three different groups of albino rats, which include control, 15 and 30 days methanol intoxication. Our study reports that animal body weight, organ weight ratio, lymphoid cell counts, footpad thickness, antibody titer, IL-2, TNF-alpha, IFN-gamma, Pan T cell, CD4, macrophages, MHC class II molecule expression, and B cell counts were significantly decreased compared to control animals nevertheless, LMI, IL-4, and DNA single strand breakage were increased significantly. Plasma corticosterone level was significantly increased in the 15 days group whereas the 30 days methanol intoxication group showed considerable decrease in corticosterone level compared with control animals. Therefore, our investigation concluded that repeated exposure of methanol profoundly suppressed the cell mediated and humoral immune functions in albino rats. 相似文献
995.
Studer B Boller B Bauer E Posselt UK Widmer F Kölliker R 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,115(1):9-17
Crown rust, caused by Puccinia coronata f. sp. lolii, is one of the most important diseases of temperate forage grasses, such as ryegrasses (Lolium spp.), affecting yield and nutritional quality. Therefore, resistance to crown rust is a major goal in ryegrass breeding
programmes. In a two-way pseudo-testcross population consisting of 306 Lolium multiflorum individuals, multisite field evaluations as well as alternative methods based on artificial inoculation with natural inoculate
in controlled environments were used to identify QTLs controlling resistance to crown rust. Disease scores obtained from glasshouse
and leaf segment test (LST) evaluations were highly correlated with scores from a multisite field assessment (r = 0.66 and 0.79, P < 0.01, respectively) and thus confirmed suitability of these methods for crown rust investigations. Moreover, QTL mapping
based on a linkage map consisting of 368 amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers
revealed similar results across different phenotyping methods. Two major QTLs were consistently detected on linkage group
(LG) 1 and LG 2, explaining up to 56% of total phenotypic variance (V
p). Nevertheless, differences between position and magnitude of QTLs were observed among individual field locations and suggested
the existence of specific local pathogen populations. The present study not only compared QTL results among crown rust evaluation
methods and environments, but also identified molecular markers closely linked to previously undescribed QTLs for crown rust
resistance in Italian ryegrass with the potential to be applied in marker-assisted forage crop breeding.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
996.
In bilingual communities, mixing languages is avoided in formal schooling: even if two languages are used on a daily basis for teaching, only one language is used to teach each given academic subject. This tenet known as the one subject-one language rule avoids mixing languages in formal schooling because it may hinder learning. The aim of this study was to test the scientific ground of this assumption by investigating the consequences of acquiring new concepts using a method in which two languages are mixed as compared to a purely monolingual method. Native balanced bilingual speakers of Basque and Spanish—adults (Experiment 1) and children (Experiment 2)—learnt new concepts by associating two different features to novel objects. Half of the participants completed the learning process in a multilingual context (one feature was described in Basque and the other one in Spanish); while the other half completed the learning phase in a purely monolingual context (both features were described in Spanish). Different measures of learning were taken, as well as direct and indirect indicators of concept consolidation. We found no evidence in favor of the non-mixing method when comparing the results of two groups in either experiment, and thus failed to give scientific support for the educational premise of the one subject—one language rule. 相似文献
997.
Michael H. Cortez 《Theoretical Ecology》2015,8(3):369-382
Eco-coevolutionary theory predicts that predator-prey coevolution occurring on the time scale of ecological dynamics (e.g., changes in population abundances) can drive novel kinds of predator-prey cycles, e.g., cryptic cycles where one species cycles while the other remains effectively constant and clockwise cycles where peaks in predator density precede peaks in prey density. However, because this body of theory has focused on particular models and studied the different cycle types in isolation, it is unclear what biological characteristics (e.g., costs for offense or defense) determine when a particular cycle type will arise. In this study, I explore the kinds of predator-prey cycles that arise in a general eco-coevolutionary model where there is disruptive selection and the coevolutionary dynamics are fast relative to the ecological dynamics of the system. With a graphical tool created using the theory of fast-slow dynamical systems, I predict what kinds of cycles can arise in the model and how cycle type depends on the costs for prey defense and predator offense. Fast-slow dynamical systems theory requires a separation of time scales between the ecological and evolutionary processes; however, numerical simulations show that this tool can help predict how coevolution drives populations cycles in systems where the speeds of ecological and evolutionary dynamics are comparable. Thus, this work is a step forward in building a general eco-coevolutionary theory. 相似文献
998.
Puja Seth Mary Glenshaw Jennifer H. F. Sabatier René Adams Verona Du Preez Nickolas DeLuca Naomi Bock 《PloS one》2015,10(3)
Objectives
To describe alcohol drinking patterns among participants in Katutura, Namibia, and to evaluate brief versions of the AUDIT against the full AUDIT to determine their effectiveness in detecting harmful drinking.Methods
A cross-sectional survey was conducted in four constituencies and 639 participants, 18 years or older, completed a sociodemographic survey and the AUDIT. The effectiveness of the AUDIT-C (first three questions) and the AUDIT-3 (third question) was compared to the full AUDIT.Results
Approximately 40% were identified as harmful, hazardous or likely dependent drinkers, with men having a higher likelihood than women (57.2% vs. 31.0%, p<.0001). Approximately 32% reported making and/or selling alcohol from home. The AUDIT-C performed best at a cutoff ≥ 3, better in men (sensitivity: 99.3%, specificity: 77.8%) than women (sensitivity: 91.7%, specificity: 77.4%). The AUDIT-3 performed poorly (maximum sensitivity: < 90%, maximum specificity: <51%). According to AUROC, the AUDIT-C performed better than the AUDIT-3.Conclusions
A large proportion of participants met criteria for alcohol misuse, indicating a need for screening and referral for further evaluation and intervention. The AUDIT-C was almost as effective as the full AUDIT and may be easier to implement in clinical settings as a routine screening tool in resource-limited settings because of its brevity. 相似文献999.
1000.
Paenibacillus graminis strains were described recently as cyclodextrin (CD) producers. Cyclodextrins are produced by cyclodextrin glucanotransferase
(CGTase) which has not been characterized in P. graminis. Similar amounts of α- and β-CDs were produced by P. graminis (MC22.13) and P. macerans (LMD24.10T). Primers were designed to sequence the gene encoding CGTase from P. graminis. A phylogenetic tree was constructed and P. graminis CGTase protein showed to be closer (79.4% protein identity) to P. macerans |P31835|. Hybridization studies suggested that the gene encoding CGTase is located in different positions in the genomes
of P. macerans and P. graminis. 相似文献