1,570 research outputs found
The effects of color contrast on performance of the WAIS-R digit symbol subtest
Color contrast has been shown to aid in visual search tasks using electronic displays, while the research regarding the usefulness of color contrast in aiding visual search using a paper medium is mixed. The present study questions whether subjects’ performance will improve on a paper task where the search target is in high color contrast when compared with a task where the target color does not differ from the rest of the search field.
Thirty-nine adults with normal vision were administered two forms of the WAIS-R digit symbol subtest, one with low chromatic contrast and one with high chromatic contrast, in a within-subjects design. No significant difference was found in performance on the two tasks. Explanations offered for these results include the effects of surround luminance, contrast of saturation, and short-term visual memory
Complexity of diatom response to Lateglacial and Holocene climate and environmental change in ancient, deep and oligotrophic Lake Ohrid (Macedonia and Albania)
© Author(s) 2016. Lake Ohrid (Macedonia and Albania) is a rare example of a deep, ancient Mediterranean lake and is a key site for palaeoclimate research in the northeastern Mediterranean region. This study conducts the analysis of diatoms as a proxy for Lateglacial and Holocene climate and environmental change in Lake Ohrid at a higher resolution than in previous studies. While Lake Ohrid has the potential to be sensitive to water temperature change, the data demonstrate a highly complex diatom response, probably comprising a direct response to temperature-induced lake productivity in some phases and an indirect response to temperaturerelated lake stratification or mixing and epilimnetic nutrient availability in others. The data also demonstrate the possible influence of physical limnological (e.g. the influence of wind stress on stratification or mixing) and chemical processes (e.g. the influence of catchment dynamics on nutrient input) in mediating the complex response of diatoms. During the Lateglacial (ca. 12 300-11 800 cal yr BP), the low-diversity dominance of hypolimnetic Cyclotella fottii indicates low lake productivity, linked to low water temperature. Although the subsequent slight increase in small, epilimnetic C. minuscula during the earliest Holocene (ca. 11 800-10 600 cal yr BP) suggests climate warming and enhanced stratification, diatom concentration remains as low as during the Lateglacial, suggesting that water temperature increase was muted across this major transition. The early Holocene (ca. 10 600-8200 cal yr BP) is characterised by a sustained increase in epilimnetic taxa, with mesotrophic C. ocellata indicating high water-temperature-induced productivity between ca. 10 600-10 200 cal yr BP and between ca. 9500-8200 cal yr BP and with C. minuscula in response to low nutrient availability in the epilimnion between ca. 10 200-9500 cal yr BP. During the middle Holocene (ca. 8200-2600 cal yr BP), when sedimentological and geochemical proxies provide evidence for maximum Holocene water temperature, anomalously low C. ocellata abundance is probably a response to epilimnetic nutrient limitation, almost mimicking the Lateglacial flora apart from the occurrence of mesotrophic Stephanodiscus transylvanicus in the hypolimnion. During the late Holocene (ca. 2600 cal yr BP-present), high abundance and fluctuating composition of epilimnetic taxa are probably a response more to enhanced anthropogenic nutrient input, particularly nitrogen enrichment, than to climate. Overall, the data indicate that previous assumptions concerning the linearity of diatom response in this deep, ancient lake are invalid, and multi-proxy analysis is essential to improve understanding of palaeolimnological dynamics in future research on the long, Quaternary sequence
An important role for Myb-MuvB and its target gene KIF23 in a mouse model of lung adenocarcinoma
The conserved Myb-MuvB (MMB) multiprotein complex has an important role in transcriptional activation of mitotic genes. MMB target genes are overexpressed in several different cancer types and their elevated expression is associated with an advanced tumor state and a poor prognosis. This suggests that MMB could contribute to tumorigenesis by mediating overexpression of mitotic genes. However, although MMB has been extensively characterized biochemically, the requirement for MMB in tumorigenesis in vivo has not been investigated. Here we demonstrate that MMB is required for tumor formation in a mouse model of lung cancer driven by oncogenic K-RAS. We also identify a requirement for the mitotic kinesin KIF23, a key target gene of MMB, in tumorigenesis. RNA interference-mediated depletion of KIF23 inhibited lung tumor formation in vivo and induced apoptosis in lung cancer cell lines. Our results suggest that inhibition of KIF23 could be a strategy for treatment of lung cancer
Das enttäuschte Versprechen der Integration: Migrantennachkommen in Frankreich und Deutschland
Dieser Beitrag beschäftigt sich mit den sozialstrukturellen Voraussetzungen, die der Dynamik bzw. dem Ausbleiben von Protestverhalten zu Grunde liegen. Ausgehend von drei theoretischen Erklärungsansätzen wird empirisch anhand von repräsentativen Mikrodaten gezeigt, dass die Konzeption der Integration der Migrantennachkommen durch die Staatsbürgerschaft und die Schule in Frankreich als ein Versprechen der Integration verstanden werden kann, das im Übergang auf den Arbeitsmarkt strukturell enttäuscht wird. Demgegenüber setzt die Ausgrenzung von Migrantennachkommen in Deutschland schon im Bildungssystem ein, so dass größere Erwartungshaltungen gar nicht erst entstehen. Die Revolten der jungen MigrantInnen in Frankreich können damit u.a. als Ergebnis von strukturell enttäuschten Erwartungen interpretiert werden.Integration, Zweite Generation, Migration, Deutschland, Frankreich
Corrigendum to “Pollen-based paleoenvironmental and paleoclimatic change at Lake Ohrid (south-eastern Europe) during the past 500 ka” published in Biogeosciences, 13, 1423–1437, 2016
In this corrigendum we report an updated pollen record from the Lake Ohrid DEEP site spanning the past 500 ka whereby we have reprocessed and re-analyzed 104 samples affected by chemical procedure problems that occurred in one palynological laboratory. Firstly, these samples were affected by the use of wrong containers, causing in- adequate settling of particles at the set centrifuging speed. Secondly, HCl and HF treatments were combined without the prescribed intermediate centrifuging and decanting steps. The inaccuracy in the protocol resulted in the loss of smaller pollen grains and in the overrepresentation of bisaccate ones in most of the re-analyzed samples. We therefore provide an updated set of figures with the new data and have revised the description of the results, discussion and conclusions re- ported in Sadori et al. (2016) where necessary. We stress that the majority of the original results and conclusions remain valid, while the records’ reliability and resolution have improved as 12 samples that had been omitted in the original study because of low count sums are now included in the revised dataset (Sadori et al., 2018)
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Age–depth model of the past 630 kyr for Lake Ohrid (FYROM/Albania) based on cyclostratigraphic analysis of downhole gamma ray data
Gamma ray (GR) fluctuations and potassium (K) values from downhole logging data obtained in the sediments of Lake Ohrid from 0 to 240 m below lake floor (b.l.f). correlate with fluctuations in δ18O values from the global benthic isotope stack LR04 (Lisiecki and Raymo, 2005). GR and K values are considered a reliable proxy to depict glacial-interglacial cycles, with high clastic input during cold and/or drier periods and high carbonate precipitation during warm and/or humid periods at Lake Ohrid. Spectral analysis was applied to investigate the climate signal and evolution over the length of the borehole. Linking downhole logging data with orbital cycles was used to estimate sedimentation rates and the effect of compaction was compensated for. Sedimentation rates increase on average by 14 % after decompaction of the sediment layers and the mean sedimentation rates shift from 45 cm kyr-1 between 0 and 110 m to 30 cm kyr-1 from 110 to 240 m b.l.f. Tuning of minima and maxima of gamma ray and potassium values versus LR04 extrema, in combination with eight independent tephrostratigraphical tie points, allows establishing of a robust age model for the downhole logging data over the past 630 kyr. © Author(s) 2015
Ly-alpha Emission-Line Galaxies at z = 3.1 in the Extended Chandra Deep Field South
We describe the results of an extremely deep, 0.28 deg^2 survey for z = 3.1
Ly-alpha emission-line galaxies in the Extended Chandra Deep Field South. By
using a narrow-band 5000 Anstrom filter and complementary broadband photometry
from the MUSYC survey, we identify a statistically complete sample of 162
galaxies with monochromatic fluxes brighter than 1.5 x 10^-17 ergs cm^-2 s^-1
and observers frame equivalent widths greater than 80 Angstroms. We show that
the equivalent width distribution of these objects follows an exponential with
a rest-frame scale length of w_0 = 76 +/- 10 Angstroms. In addition, we show
that in the emission line, the luminosity function of Ly-alpha galaxies has a
faint-end power-law slope of alpha = -1.49 +/- 0.4, a bright-end cutoff of log
L^* = 42.64 +/- 0.2, and a space density above our detection thresholds of 1.46
+/- 0.12 x 10^-3 h70^3 galaxies Mpc^-3. Finally, by comparing the emission-line
and continuum properties of the LAEs, we show that the star-formation rates
derived from Ly-alpha are ~3 times lower than those inferred from the
rest-frame UV continuum. We use this offset to deduce the existence of a small
amount of internal extinction within the host galaxies. This extinction,
coupled with the lack of extremely-high equivalent width emitters, argues that
these galaxies are not primordial Pop III objects, though they are young and
relatively chemically unevolved.Comment: 45 pages, 15 figures, accepted for publication in the Astrophysical
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