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68462. The quality of aphids as food for generalist predators: implications for natural control of aphids
- Creator:
- Toft, Soren
- Type:
- article, model:article, and TEXT
- Subject:
- Polyphagous aphidiphages, specialist aphidiphages, true generalist predators, alternative prey, Araneae, Opiliones, Coleoptera, Hymenoptera, Dictyoptera, and Aves
- Language:
- English
- Description:
- The paper reviews existing data on the food quality of cereal aphids for generalist predators. Data are presented for spiders, harvestmen, carabid and staphylinid beetles, cockroaches, ants and one species of bird. All results agree that cereal aphids are low-quality food compared to alternative prey types (in most studies fruit flies). This is associated both with a low consumption capacity for aphids and a low utilization efficiency of the aphid food. A pure aphid diet allows full juvenile development in only a few species. Aphids as part of mixed diets can have negative, neutral or positive effects, which depends on the quality of the remaining diet. The low consumption capacity for aphids is due to the development of a specific feeding aversion. Genetic variation in the ability to tolerate aphids has been documented, indicating that predators may be able to adapt to a higher proportion of aphids in the diet in areas where outbreaks are frequent. A consequence of these findings is that predator populations rely on alternative prey (e.g. Collembola and Diptera) for maintenance and reproduction, and are probably unable to benefit nutritionally from an aphid outbreak. The low food quality of aphids to generalist predators explains why generalist and specialist predators have widely different roles in aphid biocontrol, but does not rule out that under some conditions the generalists may be able to inhibit aphid population growth sufficiently to prevent an outbreak, as field experiments have indicated. Simulation modelling shows that a low consumption capacity for aphids has little influence on the ability to prevent aphid population increase at low aphid immigration rates, but a great influence at high aphid immigration rates. Modelling also indicates that there may be an optimal availability of high-quality alternative prey that maximizes the impact of generalist predators on aphid population growth.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
68463. The quality of meteorological observations and tropospheric delay from EPN/IGS permanent stations located in the Sudety Mountains and in the adjacent areas
- Creator:
- Rohm, Witold and Bosy, Jarosław
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, meteorologie, meteorology, Krkonošsko-jesenická soustava (pohoří), Sudety mountains, GPS for meteorology, tropospheric delay, GNSS permanent stations, precise GPS positioning, 7, and 551
- Language:
- English
- Description:
- The mountain type of climate, which is typical for the Sudety Mountains, is well known for its rapid and frequent changes in pressure, temperature and humidity. The fluctuations in meteorological parameters cause fast changes of the tropospheric delay, as a correlated value, and in consequence difficulties in GPS heights determination. The tropospheric delay is a function of the meteorological parameters obtained directly from synoptic stations and models. The paper presents the procedure of tropospheric delay estimation on the European Permanent Network and International GNSS Service (EPN/IGS) stations, using meteorological observations from synoptic stations (Wrocław Airport, Śnieżka) of the Polish Meteorology Service (IMGW), stations (Cervena, Praha-Kbely) of the Czech Hydrometeorological Institute (CHMU), and sensors mounted close to the antennas of the permanent GNSS stations (BISK, SNEC, WROC, GOPE). The values obtained from Global Pressure and Temperature (GPT) model were bases for the meteorological data calibration at EPN/IGS stations. The tropospheric delay (Zenith Total Delay - ZTD) on EPN/IGS stations was obtained from Saastamoinen formula and compared with ZTD from EPN solutions., Witold Rohm and Jarosław Bosy., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
68464. The quantitation of 7β-hydroxy-epiandrosterone in the plasma and seminal plasma of men with different degrees of fertility
- Creator:
- Jana Vítků, Lucie Kolátorová Sosvorová, Ricco, C, Ferroud, C, Hennebert, O, Škodová, T, Jiří Heráček, and Luboslav Stárka
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- steroidy, rozmnožování (biologie), steroids, reproduction, 7β-hydroxy-epiandrosterone, sperm quality, steroidogenesis, seminal plasma, 14, and 612
- Language:
- English
- Description:
- 7β-hydroxy-epiandrosterone (7β-OH-EpiA) is an endogenous androgen metabolite that has been shown to exert neuroprotective, anti-inflammatory and anti-estrogenic effects. However, to the best of our knowledge no information is available about this androgen steroid in relation to sperm quality. We analyzed 7β-OH-EpiA in plasma and seminal plasma using a newly developed isotope dilution ultra-high performance liquid chromatography - mass spectrometry method. Validation met the requirements of FDA guidelines. Levels of 7β-OH-EpiA were measured in 191 men with different degrees of infertility. One-way analysis of variance followed by multiple comparison and correlation analysis adjusted for age, BMI and abstinence time were performed to evaluate the relationships between this steroid and sperm quality. Concentrations of 7β-OH-EpiA in seminal plasma were significantly higher in severely infertile men in comparison with healthy men and slightly infertile men. The same trend was found when blood plasma was evaluated. Furthermore, plasma 7β-OH-EpiA negatively correlated with sperm concentration (-0.215; p<0.01) and total count (-0.15; p<0.05). Seminal 7β-OH-EpiA was negatively associated with motility (-0.26; p<0.01), progressively motile spermatozoa (-0.233; p<0.01) and nonprogressively motile spermatozoa (-0.188; p<0.05). 7β-OH-EpiA is associated with lower sperm quality and deserves more research in that respect., J. Vitku, L. Kolatorova, C. Ricco, C. Ferroud, O. Hennebert, T. Skodova, J. Heracek, L. Starka., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
68465. The quasi-canonical solution operator to $\bar{\partial}$ restricted to the Fock-space
- Creator:
- Schneider, Georg
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Fock-space, Hankel-operator, and reproducing kernel
- Language:
- English
- Description:
- We consider the solution operator $S\:\mathcal F_{\mu ,(p,q)}\rightarrow L^2(\mu )_{(p,q)}$ to the $\bar{\partial }$-operator restricted to forms with coefficients in $\mathcal F_{\mu }= \bigl \lbrace f\: f \text{is} \text{entire} \text{and} \int _{\mathbb{C}^n} |f(z)|^2\mathrm{d}\mu (z) <\infty \bigr \rbrace $. Here $\mathcal F_{\mu ,(p,q)}$ denotes $(p,q)$-forms with coefficients in $\mathcal F_{\mu }$, $L^2(\mu )$ is the corresponding $L^2$-space and $\mu $ is a suitable rotation-invariant absolutely continuous finite measure. We will develop a general solution formula $S$ to $\bar{\partial }$. This solution operator will have the property $Sv\bot \mathcal F_{(p,q)}\, \forall \,v \in \mathcal F_{(p,q+1)}$. As an application of the solution formula we will be able to characterize compactness of the solution operator in terms of compactness of commutators of Toeplitz-operators $[T_{\bar{z_i}},T_{z_i}]= [T^*_{{z_i}},T_{z_i}]\:\mathcal F_\mu \rightarrow L^2(\mu )$.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
68466. The question of "Japaneseness" and the creation of the "Greater Oriental Design" for crafts of the Japanese empire
- Creator:
- Kikuchi, Yuko
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- craft and design, Japanese empire, North China/Manchuria, and Taiwan
- Language:
- English
- Description:
- Since the 19th century, crafts for Japan have been as important for trade and the economy as they have been for national and cultural identity. The discourse of "Japaneseness" has been central to the national and public debate in the craft world. As the Japanese empire expanded into North East China in the 1930s, Japan became interested in the cultures of greater China, including Taiwan. Japan´s continuous obsession with the idea of the "Japaneseness" in craft products was complicated by its effort to redefine itself in terms of its "Orientalness". This involved the location of its identity within the three-way positioning of Occident-Jaoan-Orient rather than the simple binary position of Japan versus the Occident. This aper firstly examines how Japanese craft and design experts confronted these multiple and different shades of the Orient and constructed the notion of "Japaneseness" as part of the Orient in the design discourse. Secondly, it will investigate the Japan centric hybrid design concept of "Greater Oriental Design", articulated by Japan as the leading power and authority of crafts in Asia. Finally, this paper will explore how this design discourse and these concepts were creatively interpreted in actual design terms and in experimentation, as well as the resulting implications for Japanese design history.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
68467. The questions of 1968: background, context and retrospect
- Creator:
- Arnason, Johann P.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Language:
- Czech
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
68468. The radio studies of Virgo cluster spirals at 10.7 GHz
- Creator:
- Urbanik, M., Klein, U., and Gräve, R.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- astronomy, Virgo cluster spirals, and radio telescopes
- Language:
- Czech
- Description:
- The 10.7 GHz observation of four Virgo cluster spirals made with the 100 m MPIfH radio telescope are examined for possible effects of the cluster environment. Their radio structure parameters were compared to these known from observations of nearby field spirals. A search for an anomalous composition of the 10.7 GHz radiation and for a general deficiency of these spirals relative to field galaxies has been also made.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
68469. The range of insect dormancy responses
- Creator:
- Danks, Hugh V.
- Type:
- article, model:article, and TEXT
- Subject:
- Insect, life-cycle, development, dormancy, diapause, trade-off, constraint, variation, and plasticity
- Language:
- English
- Description:
- Insect dormancy responses, in the broad sense of modifications of development, are examined from a general perspective. The range of responses is extraordinarily wide because environments are diverse, different taxa have different evolutionary histories, adaptations are needed for both seasonal timing and resistance to adversity, and not only development but also many other aspects of the life-cycle must be coordinated. Developmental options are illustrated by examining the wide range of ways in which development can be modified, the fact that each individual response consists of several components, and the different potential durations of the life-cycle. The concepts of alternative life-cycle pathways (chosen according to current and likely future environmental conditions) and of active and passive default responses are treated. Also introduced are aspects of variation and trade-offs. Some general conclusions that help in understanding dormancy responses emerge from such an examination. Many options are available (cf. Table 1). The nature of the habitat, especially its predictability, determines the potential effectiveness of many of the developmental options. Any particular set of responses reflects evolutionary history and hence depends on past as well as current environments. It is not necessarily obvious what kinds of selection, especially requirements for timing versus resistance to adversity, explain a particular life cycle. Life-cycle pathways have multiple components, so that components cannot be analyzed in isolation. A given feature, such as delayed development, can have multiple roles. Default responses can be either active (development continues unless signalled otherwise) or passive (development stops unless signalled otherwise), making necessary a broad approach to understanding the action of environmental cues. Even relatively minor effects that fine-tune dormancy responses enhance survival, but may be difficult to detect or measure. Trade-offs are not inevitable, not only when certain resources are surplus, but also because resources in very short supply (constraints) cannot be traded off. Life-cycle components are widely, but not universally, coordinated. These conclusions confirm that the range of dormancy responses is wider, more complex and more integrated than has often been recognized.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
68470. The range of non-linear natural polynomials cannot be context-free
- Creator:
- Pálvölgyi, Dömötör
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- contex-free languages and pumping lemma
- Language:
- English
- Description:
- Suppose that some polynomial f with rational coefficients takes only natural values at natural numbers, i. e., L={f(n)∣n∈N}⊆N. We show that the base-q representation of L is a context-free language if and only if f is linear, answering a question of Shallit. The proof is based on a new criterion for context-freeness, which is a combination of the Interchange lemma and a generalization of the Pumping lemma.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public