137 research outputs found

    Recall of paired-associates as a function of overt and covert rehearsal procedures

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    Effect on memory of mode of studying paired associates, and mathematical model employing short term rehearsal buffer and long term memor

    Leadership issues, concerns, and competencies of senior level student affairs professionals: a study of a 4 year public university

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    The purpose of this study was to analyze the leadership competencies commonly exhibited by selected student affairs professionals at a 4-year public university in the northeast. To have a deeper understanding of leadership within the field of student affairs, issues and concerns were investigated using relevant leadership theories (Eddy & VanDerLinden, 2006). The study sought to close the gap in the literature base by examining a division of student affairs from the director (or equivalent positions) up to the vice president of the division. Twenty one participants were selected because of their rank of senior level student affairs professionals at Public University. Of these 21 individuals 19 participated in the study. All participants completed Linkage Incorporated\u27s Leadership Assessment Instrument (LAI), and an interview conducted by the researcher. The findings suggested that selected administrators at Public University employ all five leadership competencies evenly, and their concerns are strongly related to their chosen leadership practice

    Range-Wide Sex-Chromosome Sequence Similarity Supports Occasional XY Recombination in European Tree Frogs (Hyla arborea).

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    In contrast with mammals and birds, most poikilothermic vertebrates feature structurally undifferentiated sex chromosomes, which may result either from frequent turnovers, or from occasional events of XY recombination. The latter mechanism was recently suggested to be responsible for sex-chromosome homomorphy in European tree frogs (Hyla arborea). However, no single case of male recombination has been identified in large-scale laboratory crosses, and populations from NW Europe consistently display sex-specific allelic frequencies with male-diagnostic alleles, suggesting the absence of recombination in their recent history. To address this apparent paradox, we extended the phylogeographic scope of investigations, by analyzing the sequences of three sex-linked markers throughout the whole species distribution. Refugial populations (southern Balkans and Adriatic coast) show a mix of X and Y alleles in haplotypic networks, and no more within-individual pairwise nucleotide differences in males than in females, testifying to recurrent XY recombination. In contrast, populations of NW Europe, which originated from a recent postglacial expansion, show a clear pattern of XY differentiation; the X and Y gametologs of the sex-linked gene Med15 present different alleles, likely fixed by drift on the front wave of expansions, and kept differentiated since. Our results support the view that sex-chromosome homomorphy in H. arborea is maintained by occasional or historical events of recombination; whether the frequency of these events indeed differs between populations remains to be clarified

    First-generation linkage map for the European tree frog (Hyla arborea) with utility in congeneric species.

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    BACKGROUND: Western Palearctic tree frogs (Hyla arborea group) represent a strong potential for evolutionary and conservation genetic research, so far underexploited due to limited molecular resources. New microsatellite markers have recently been developed for Hyla arborea, with high cross-species utility across the entire circum-Mediterranean radiation. Here we conduct sibship analyses to map available markers for use in future population genetic applications. FINDINGS: We characterized eight linkage groups, including one sex-linked, all showing drastically reduced recombination in males compared to females, as previously documented in this species. Mapping of the new 15 markers to the ~200 My diverged Xenopus tropicalis genome suggests a generally conserved synteny with only one confirmed major chromosome rearrangement. CONCLUSIONS: The new microsatellites are representative of several chromosomes of H. arborea that are likely to be conserved across closely-related species. Our linkage map provides an important resource for genetic research in European Hylids, notably for studies of speciation, genome evolution and conservation

    Understorey light quality affects leaf pigments and leaf phenology in different plant functional types

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    Forest understorey plants receive most sunlight in springtime before canopy closure, and in autumn following leaf-fall. We hypothesized that plant species must adjust their phenological and photoprotective strategies in response to large changes in the spectral composition of the sunlight they receive. Here, we identified how plant species growing in northern deciduous and evergreen forest understoreys differ in their response to blue light and ultraviolet (UV) radiation according to their functional strategy. We installed filters in a forest understorey in southern Finland, to create the following treatments attenuating: UV radiation < 350 nm, all UV radiation (< 400 nm), all blue light and UV radiation (< 500 nm), and a transparent control. In eight species, representing different functional strategies, we assessed leaf optical properties, phenology, and epidermal flavonoid contents over two years. Blue light accelerated leaf senescence in all species measured in the understorey, apart from Quercus robur seedlings, whereas UV radiation only accelerated leaf senescence in Acer platanoides seedlings. More light-demanding species accumulated flavonols in response to seasonal changes in light quality compared to shade-tolerant and wintergreen species and were particularly responsive to blue light. Reduction of blue and UV radiation under shade reveals an important role for microclimatic effects on autumn phenology and leaf photoprotection. An extension of canopy cover under climate change, and its associated suppression of understorey blue light and UV radiation, may delay leaf senescence for understorey species with an autumn niche.Peer reviewe

    Timeframe of speciation inferred from secondary contact zones in the European tree frog radiation (Hyla arborea group).

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    BACKGROUND: Hybridization between incipient species is expected to become progressively limited as their genetic divergence increases and reproductive isolation proceeds. Amphibian radiations and their secondary contact zones are useful models to infer the timeframes of speciation, but empirical data from natural systems remains extremely scarce. Here we follow this approach in the European radiation of tree frogs (Hyla arborea group). We investigated a natural hybrid zone between two lineages (Hyla arborea and Hyla orientalis) of Mio-Pliocene divergence (~5 My) for comparison with other hybrid systems from this group. RESULTS: We found concordant geographic distributions of nuclear and mitochondrial gene pools, and replicated narrow transitions (~30 km) across two independent transects, indicating an advanced state of reproductive isolation and potential local barriers to dispersal. This result parallels the situation between H. arborea and H. intermedia, which share the same amount of divergence with H. orientalis. In contrast, younger lineages show much stronger admixture at secondary contacts. CONCLUSIONS: Our findings corroborate the negative relationship between hybridizability and divergence time in European tree frogs, where 5 My are necessary to achieve almost complete reproductive isolation. Speciation seems to progress homogeneously in this radiation, and might thus be driven by gradual genome-wide changes rather than single speciation genes. However, the timescale differs greatly from that of other well-studied amphibians. General assumptions on the time necessary for speciation based on evidence from unrelated taxa may thus be unreliable. In contrast, comparative hybrid zone analyses within single radiations such as our case study are useful to appreciate the advance of speciation in space and time

    Greater capacity to exploit warming temperatures in northern populations of European beech is partly driven by delayed leaf senescence

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    One of the most widespread consequences of climate change is the disruption of trees’ phenological cycles. The extent to which tree phenology varies with local climate is largely genetically determined, and while a combination of temperature and photoperiodic cues are typically found to trigger bud burst (BB) in spring, it has proven harder to identify the main cues driving leaf senescence (LS) in autumn. We used 905 individual field observations of BB and LS from six Fagus sylvatica populations, covering the range of environmental conditions found across the species distribution, to: (i) estimate the dates of BB and LS of these populations; (ii) assess the main drivers of LS; and (iii) predict the likely variation in growing season length (GSL; defined as the period from BB to LS timing) across populations under current and future climate scenarios. To this end, we first calibrated linear mixed-effects models for LS as a function of temperature, insolation and BB date. Secondly, we calculated GSL for each population as the number of days between BB and LS. We found that: i) there were larger differences among populations in the date of BB than in the date of LS; ii) the temperature through September, October and November was the main determinant of LS, although covariation of temperature with daily insolation and precipitation-related variables suggests that all three variables may affect LS timing; and iii) GSL was predicted to increase in northern populations and to shrink in central and southern populations under climate change. Consequently, the large present-day differences in GSL across the range of beech are likely to decrease under future climates where rising temperatures will alter the relationship between BB and LS. Northern populations are likely to increase their productivity as warmer conditions will enable them to extend their growing season.Peer reviewe

    Patterns in the spectral composition of sunlight and biologically meaningful spectral photon ratios as affected by atmospheric factors

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    Plants rely on spectral cues present in their surroundings, generated by the constantly changing light environment, to guide their growth and reproduction. Photoreceptors mediate the capture of information by plants from the light environment over a wide range of wavelengths, but despite extensive evidence that plants respond to various light cues, only fragmentary data have been published showing patterns of diurnal, seasonal and geographical variation in the spectral composition of daylight. To illustrate patterns in spectral photon ratios, we measured time series of irradiance spectra at two distinct geographical and climatological locations, Helsinki, Finland and Gual Pahari, India. We investigated the drivers behind variation of the spectral photon ratios measured at these two locations, based on the analysis of over 400 000 recorded spectra. Differences in spectral irradiance were explained by different atmospheric factors identified through multiple regression model analysis and comparison to spectral irradiance at ground level simulated with a radiative transfer model. Local seasonal and diurnal changes in spectral photon ratios were related to solar elevation angle, atmospheric water-vapour content and total ozone column thickness and deviated from their long-term averages to an extent likely to affect plant photobiology. We suggest that future studies should investigate possible effects of varying photon ratios on terrestrial plants. Solar elevation angle especially affects the patterns of B:G and B:R ratios. Water vapour has a large effect on the R:FR photon ratio and modelled climate scenarios predict that increasing global temperatures will result in increased atmospheric water vapour. The development of proxy models, utilising available data from weather and climate models, for relevant photon ratios as a function of solar elevation angle and atmospheric factors would facilitate the interpretation of results from past, present and future field studies of plants and vegetation.Peer reviewe

    Flamingo Vol. I N 3

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    Voo-Doo. Untitled. Prose. 1. Widow. Untitled. Prose. 1. Tiger. Untitled. Prose. 1. Purple Cow. Untitled. Prose. 1. Anonymous. Untitled. Prose. 1. Life. Untitled. Prose. 2. Yale Record. Untitled. Prose. 2. Voo-Doo. Untitled. Prose. 2. Sour Owl. Untitled. Prose. 2. Puppet. Untitled. Prose. 2. Sun Dial. Untitled. Prose. 2. Anonymous. Untitled. Prose. 2. Nottingham, Ruth. Teddy . Prose. 5. Grogan. Untitled. Picture. 7. Anonymous. Untitled. Prose. 7. Anonymous. An Easy One . Prose. 7. Anonymous. How Terrible! Prose. 7. Anonymous. Untitled. Prose. 7. Anonymous. Untitled. Poem. 7. F.H.G. Untitled. Picture. 7. Wood, J.E.F. When mother Went to College . Prose. 8. E.D.T. Chicago Corn Exchange . Poem. 8. Anonymous. Untitled. Prose. 8. Anonymous. Untitled. Poem. 8. Anonymous. All But . Prose. 8. R.D.B. Roscoe to The Rescue . Prose. 9. Leet, L.D. On The Efficacy of Dreams . Prose. 10. Orange Ade. The Fable of the Coffin Nailer . Prose. 11. Orange Ade. Time Wasted . Prose. 11. Orange Ade. The Americanized Boy . Prose. 11. Orange Ade. Anything to Oblige . Prose. 11. Orange Ade. Tit For Tat . Prose. 11. Orange Ade. Good Alibi . Prose. 11. Orange Ade. Untitled. Prose. 11. Grogan. Untitled. Picture. 11. Lusk, R.G. On The Absurdity of Catching Fish When A-Fishing . Prose. 12. Anonymous. Co-eds and Plain Eds in 1950 . Picture. 13. Potter, W.M. Letters of A Japanese Sandman . Prose. 13. Anonymous. Ex Facultate . Prose. 13. Anonymous. Untitled. Prose. 13. R.J.S. An Uplifting Influence . Picture. 13. Anonymous. Consider the Luxite Girl . Poem. 14. Anonymous. Shades of Orpheus . Poem. 14. Anonymous. With The Gospel Team . Poem. 14. Anonymous. Untitled. Prose. 14. Anonymous. Untitled. Poem. 14. Anonymous. A Dirty Trick . Prose. 14. Taylor, Elsie D. Vestigial Customs . Prose. 15. Anonymous. Untitled. Prose. 16. Anonymous. A New version of Anthropology . Prose. 18. Anonymous. A New version of Anthropology . Picture. 18. Anonymous. Untitled. Prose. 18. Funk, Dorothy K. Untitled. Picture. 18. Anonymous. A Deep one . Prose. 18. Anonymous. Take His Name . Prose. 18. Olney, Clarke. The Evolution of An Intellectual . Prose. 19. Anonymous. Untitled. Prose. 19. Anonymous. Untitled. Prose. 20. W.A.W. On Getting Up For Breakfast . Prose. 20. McCann. Untitled. Picture. 21. Anonymous. Untitled. Prose. 21. Anonymous. S.S.S. . Prose. 21. Anonymous. The Judge Disagreed . Prose. 21. Anonymous. The Modern Woman . Prose. 21. Anonymous. Denison Slang in Japan . Prose. 22. Anonymous. Being Specific . Prose. 22. Anonymous. Then The Fun Began . Prose. 22. Anonymous. Then The Fun Began . Prose. 22. Anonymous. Chess Nuts . Poem. 22. Anonymous. Chess Nuts . Picture. 22. Funk, Dorothy K. Untitled. Picture. 22. Anonymous. Untitled. Prose. 22. Reel, Virginia. Untitled. Prose. 22. Anonymous. Untitled. Prose. 23. Anonymous. Take This to Heart . Prose. 23. Anonymous. Stepping Out . Picture. 23. Olney, Clarke. Untitled. Picture. 23. Anonymous. To Lalage . Prose. 23. Anonymous. Untitled. Poem. 24. Anonymous. Description of the Day . Prose. 25. Anonymous. Untitled. Prose. 25. Voo-Doo. Good Bizziness . Prose. 26. Anonymous. Fore! . Prose. 26. Anonymous. Untitled. Prose. 26. Brelsford, Ernest C. Souveniring . Prose. 27. Anonymous. Untitled. Prose. 30. Burr. Sweet Dreams . Prose. 30. Jester. Untitled. Prose. 30. Judge. Untitled. Prose. 30. Goblin. Untitled. Prose. 30. Cracker. Sanitation . Poem. 32. Anonymous. Untitled. Prose. 32. Jester. Untitled. Prose. 32. Goblin. Untitled. Prose. 32. Record. Untitled. Prose. 32. Linotype. Untitled. Prose. 32. Holt, Kilburn. The Schemer\u27s Lament . Poem. 7. Owen, Ernest t. Mother . Poem. 3. Owen, Ernest T. To--- . Poem. 24
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