scholarly journals What big eyes you have: the ecological role of giant pterygotid eurypterids

2014 ◽  
Vol 10 (7) ◽  
pp. 20140412 ◽  
Author(s):  
Ross P. Anderson ◽  
Victoria E. McCoy ◽  
Maria E. McNamara ◽  
Derek E. G. Briggs
Keyword(s):  
Visual Acuity ◽  
Compound Eyes ◽  
Ecological Role ◽  
Light Conditions ◽  
Low Light ◽  
Large Size ◽  
Arthropod Predators ◽  
High Level

Eurypterids are a group of extinct chelicerates that ranged for over 200 Myr from the Ordovician to the Permian. Gigantism is common in the group; about 50% of families include taxa over 0.8 m in length. Among these were the pterygotids (Pterygotidae), which reached lengths of over 2 m and were the largest arthropods that ever lived. They have been interpreted as highly mobile visual predators on the basis of their large size, enlarged, robust chelicerae and forward-facing compound eyes. Here, we test this interpretation by reconstructing the visual capability of Acutiramus cummingsi (Pterygotidae) and comparing it with that of the smaller Eurypterus sp. (Eurypteridae), which lacked enlarged chelicerae, and other arthropods of similar geologic age. In A. cummingsi , there is no area of lenses differentiated to provide increased visual acuity, and the interommatidial angles (IOA) do not fall within the range of high-level modern arthropod predators. Our results show that the visual acuity of A. cummingsi is poor compared with that of co-occurring Eurypterus sp. The ecological role of pterygotids may have been as predators on thin-shelled and soft-bodied prey, perhaps in low-light conditions or at night.

scholarly journals Contrast sensitivity and visual acuity under low light conditions in macular telangiectasia type 2

2018 ◽  
Vol 103 (3) ◽  
pp. 398-403 ◽  
Author(s):  
Simone Müller ◽  
Tjebo F C Heeren ◽  
Roberto Bonelli ◽  
Marcus Fruttiger ◽  
Peter Charbel Issa ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Contrast Sensitivity ◽  
Neutral Density Filter ◽  
Light Conditions ◽  
Low Light ◽  
Cross Sectional ◽  
Macular Telangiectasia ◽  
Low Luminance ◽  
Macular Telangiectasia Type 2

Background/AimMacular pigment optical density (MPOD) is centrally depleted early on in macular telangiectasia type 2 (MacTel). Contrast sensitivity (CS) might be related to MPOD, and thus impaired in early MacTel. The effect of low luminance was assessed on both CS and best corrected visual acuity (BCVA).MethodsThis is a cross-sectional study. Pelli-Robson charts were used for CS testing at 1 m in photopic (110 lux) and mesopic (1 lux) conditions. BCVA was tested with ETDRS charts and low luminance visual acuity (LLVA) with a 2.0 log unit neutral density filter. MPOD was obtained with dual-wavelength autofluorescence.ResultsOne hundred and three eyes of 52 patients with MacTel (mean±SD age 62.9±10.2, range 35–77) were compared with 34 healthy eyes of 17 controls (mean±SD age 65.2±7.4, range 53–78). CS was significantly lower in the eyes with MacTel. This impairment was higher in low light conditions (low light contrast sensitivity (LL-CS)). Eyes at the early stages of MacTel had significantly lower LL-CS than controls, but normal (photopic) CS. The results were similar but less pronounced for BCVA/LLVA. Decrease in CS was correlated with loss of MPOD.ConclusionsLow light conditions have a detrimental effect on visual performance in MacTel. Impaired CS might correlate with MPOD depletion as a pathognomonic finding in MacTel. Functional impairment might precede structural disintegration, indicating dysfunction at the cellular level. The applied tests might be useful as additional functional assessments in clinical routine and as outcome measures in future interventional clinical trials.

scholarly journals Antioxidant and Photoprotection Networking in the Coastal Diatom Skeletonema marinoi

Antioxidants ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 154 ◽  
Author(s):  
Arianna Smerilli ◽  
Sergio Balzano ◽  
Maira Maselli ◽  
Martina Blasio ◽  
Ida Orefice ◽  
...  
Keyword(s):  
External Forcing ◽  
Light Conditions ◽  
Cosmetic Products ◽  
Low Light ◽  
Physiological Regulation ◽  
Wave Distribution ◽  
Role Of Light ◽  
Antioxidant Molecule ◽  
Skeletonema Marinoi

Little is known on the antioxidant activity modulation in microalgae, even less in diatoms. Antioxidant molecule concentrations and their modulation in microalgae has received little attention and the interconnection between light, photosynthesis, photoprotection, and antioxidant network in microalgae is still unclear. To fill this gap, we selected light as external forcing to drive physiological regulation and acclimation in the costal diatom Skeletonema marinoi. We investigated the role of light regime on the concentration of ascorbic acid, phenolic compounds and among them flavonoids and their connection with photoprotective mechanisms. We compared three high light conditions, differing in either light intensity or wave distribution, with two low light conditions, differing in photoperiod, and a prolonged darkness. The change in light distribution, from sinusoidal to square wave distribution was also investigated. Results revealed a strong link between photoprotection, mainly relied on xanthophyll cycle operation, and the antioxidant molecules and activity modulation. This study paves the way for further investigation on the antioxidant capacity of diatoms, which resulted to be strongly forced by light conditions, also in the view of their potential utilization in nutraceuticals or new functional cosmetic products.

scholarly journals Transcriptomics-Aided Dissection of the Intracellular and Extracellular Roles of Microcystin in Microcystis aeruginosa PCC 7806

2014 ◽  
Vol 81 (2) ◽  
pp. 544-554 ◽  
Author(s):  
A. Katharina Makower ◽  
J. Merijn Schuurmans ◽  
Detlef Groth ◽  
Yvonne Zilliges ◽  
Hans C. P. Matthijs ◽  
...  
Keyword(s):  
Polyketide Synthase ◽  
Wild Type Strain ◽  
Carbon Limitation ◽  
Light Conditions ◽  
Wild Type ◽  
Low Light ◽  
Content Type ◽  
Expression Of Genes ◽  
Polyketide Synthase Gene

ABSTRACTRecent studies have provided evidence for both intracellular and extracellular roles of the potent hepatotoxin microcystin (MC) in the bloom-forming cyanobacteriumMicrocystis. Here, we surveyed transcriptomes of the wild-type strainM. aeruginosaPCC 7806 and the microcystin-deficient ΔmcyBmutant under low light conditions with and without the addition of external MC of the LR variant (MC-LR). Transcriptomic data acquired by microarray and quantitative PCR revealed substantial differences in the relative expression of genes of the central intermediary metabolism, photosynthesis, and energy metabolism. In particular, the data provide evidence for a lower photosystem I (PSI)-to-photosystem II (PSII) ratio and a more pronounced carbon limitation in the microcystin-deficient mutant. Interestingly, only 6% of the transcriptional differences could be complemented by external microcystin-LR addition. This MC signaling effect was seen exclusively for genes of the secondary metabolism category. The orphan polyketide synthase gene cluster IPF38-51 was specifically downregulated in response to external MC-LR under low light. Our data suggest a hierarchical and light-dependent cross talk of secondary metabolites and support both an intracellular and an extracellular role of MC inMicrocystis.

scholarly journals DENOISING ALGORITHM FOR THE PIXEL-RESPONSE NON-UNIFORMITY CORRECTION OF A SCIENTIFIC CMOS UNDER LOW LIGHT CONDITIONS

2016 ◽  
Vol XLI-B3 ◽  
pp. 749-753
Author(s):  
Changmiao Hu ◽  
Yang Bai ◽  
Ping Tang
Keyword(s):  
Imaging System ◽  
Complementary Metal Oxide Semiconductor ◽  
Cmos Image Sensor ◽  
Image Sensor ◽  
Oxide Semiconductor ◽  
Integrating Sphere ◽  
Light Conditions ◽  
Low Light ◽  
Spatial Uniformity ◽  
High Level

We present a denoising algorithm for the pixel-response non-uniformity correction of a scientific complementary metal–oxide–semiconductor (CMOS) image sensor, which captures images under extremely low-light conditions. By analyzing the integrating sphere experimental data, we present a pixel-by-pixel flat-field denoising algorithm to remove this fixed pattern noise, which occur in low-light conditions and high pixel response readouts. The response of the CMOS image sensor imaging system to the uniform radiance field shows a high level of spatial uniformity after the denoising algorithm has been applied.

Which Processes Sustain Biota in Open-Ocean Deep Chlorophyll Maxima?

2020 ◽  
Author(s):  
Shaun Rigby ◽  
Richard Williams ◽  
Eric Achterberg ◽  
Alessandro Tagliabue
Keyword(s):  
North Atlantic ◽  
Nutrient Deficiency ◽  
Marine Phytoplankton ◽  
Global Ocean ◽  
Light Conditions ◽  
Low Light ◽  
Cellular Iron ◽  
The Cost ◽  
Upward Flux

<p>Deep chlorophyll maxima (DCM) are productive layers widespread throughout the global ocean. In the DCM, marine phytoplankton are adapted to low light conditions at the cost of elevated cellular iron (Fe) requirements, leading to Fe deficient growth. To sustain productivity, nutrient demands must be met by sources such as the dissolution of sinking lithogenic particles, recycling of biogenic particles and physical transport from below. The <em>GEOTRACES</em> programme has expanded the global ocean datasets for a suite of trace metals and also noble gases. Here, we exploit helium measurements to derive a vertical flux estimate of nitrate (NO<sub>3</sub>), phosphate (PO<sub>4</sub>), silica (Si) and Fe into the DCM in the subtropical North Atlantic and equatorial Pacific. We apply the Si* relation to show differences in nutrient deficiency between waters in the DCM and the upward flux into the DCM. The offset in Si* between the DCM and upward flux may be enhanced or reduced by the dissolution of sinking particles or internal recycling. We show that the upward Fe flux to the DCM is of similar magnitude to Fe supplied through regeneration. In contrast, we show that the upward Fe flux outweighs estimates of Fe supplied to the DCM via recycling or lithogenic particles in the subtropical North Atlantic. The muted role of lithogenic particles in our estimates leads to the question: what assumptions must be made about aeolian deposition to increase the relevance of lithogenic particles at the DCM?</p>

scholarly journals DENOISING ALGORITHM FOR THE PIXEL-RESPONSE NON-UNIFORMITY CORRECTION OF A SCIENTIFIC CMOS UNDER LOW LIGHT CONDITIONS

2016 ◽  
Vol XLI-B3 ◽  
pp. 749-753 ◽  
Author(s):  
Changmiao Hu ◽  
Yang Bai ◽  
Ping Tang
Keyword(s):  
Imaging System ◽  
Complementary Metal Oxide Semiconductor ◽  
Cmos Image Sensor ◽  
Image Sensor ◽  
Oxide Semiconductor ◽  
Integrating Sphere ◽  
Light Conditions ◽  
Low Light ◽  
Spatial Uniformity ◽  
High Level

We present a denoising algorithm for the pixel-response non-uniformity correction of a scientific complementary metal–oxide–semiconductor (CMOS) image sensor, which captures images under extremely low-light conditions. By analyzing the integrating sphere experimental data, we present a pixel-by-pixel flat-field denoising algorithm to remove this fixed pattern noise, which occur in low-light conditions and high pixel response readouts. The response of the CMOS image sensor imaging system to the uniform radiance field shows a high level of spatial uniformity after the denoising algorithm has been applied.

scholarly journals Pruning Date and Cane Density Affect Primocane Development and Yield of `Autumn Bliss' Red Raspberry

HortScience ◽  
2004 ◽  
Vol 39 (3) ◽  
pp. 520-524 ◽  
Author(s):  
Pedro B. Oliveira ◽  
Cristina M. Oliveira ◽  
António A. Monteiro
Keyword(s):  
Environmental Factor ◽  
Plant Productivity ◽  
Rubus Idaeus ◽  
High Density ◽  
Assimilation Rate ◽  
Light Conditions ◽  
Red Raspberry ◽  
Low Light ◽  
Carbohydrate Reserves

The aim of this study was to determine the effects of date of summer pruning and cane densities on growth and fruiting characteristics of the raspberry (Rubus idaeus) plant. Three summer-pruning dates (early, middle, and late July) and four cane densities (8, 16, 24, and 32 canes/m row) were imposed to the greenhouse-grown primocane-fruiting raspberry `Autumn Bliss' in 2 consecutive years (1994 and 1995). A higher light microclimate and CO2 assimilation rate were measured within the canopy at the lowest density. Some compensation in CO2 assimilation rates were observed in the upper leaves of the high-density treatments, probably in response to low light. Delayed pruning decreased yield per cane and per row. The highest yields per cane were always observed at the lowest cane density. Densities of 16 and 24 canes/m produced the highest fruit yield. Light conditions appeared to be the most important environmental factor affecting plant productivity. Fruit were a weaker sink than roots; therefore, the role of carbohydrate reserves should be investigated.

Searching for ‘success’: generation, gender and onward migration in the Iranian diaspora

2017 ◽  
Vol 14 (1) ◽  
pp. 101-112 ◽  
Author(s):  
Melissa Kelly
Keyword(s):  
Life History ◽  
Young Age ◽  
Onward Migration ◽  
Social Fields ◽  
Transnational Social Fields ◽  
High Level ◽  
Iranian Diaspora

This article uses the concepts of ‘transnational social fields’ and ‘habitus’ to explore the multifaceted role families play in shaping the aspirations of onward migrating youth. The article draws on biographical life history interviews conducted with the children of Iranian migrants who were raised in Sweden but moved to London, UK as adults. The findings of the study suggest that from a young age, all the participants were pressured by their parents to perform well academically, and to achieve high level careers. These goals were easier to achieve in London than in Sweden for several reasons. Interestingly, however, participants’ understandings of what constituted success and their motivations for onward migration were nuanced and varied considerably by gender. The study contributes to an understanding of the role of multi-sited transnational social fields in shaping the aspirations of migrant youths, as well as the strategies taken up by these migrants to achieve their goals.

Decision making power of college girls in relation to clothing

2018 ◽  
Vol 9 (01) ◽  
Author(s):  
Parul Gill ◽  
Poonam Malik ◽  
Pankaj Gill
Keyword(s):  
Decision Making ◽  
Satisfaction Level ◽  
College Going ◽  
Level Of Satisfaction ◽  
High Level ◽  
Garment Design ◽  
Structured Questionnaire

The present study was undertaken to explore the decision making patterns of college girls in relation to clothing and their satisfaction level with these decision making patterns. Thirty under graduate college girls from Panipat city were approached to record their responses regarding decision making in relation to clothing and satisfaction level through a well structured questionnaire. It was found that most of the girls (56.66%) themselves made the decisions about the type of garment (Indian, western or both) they wear and majority of girls (70%) were highly satisfied with this decision making. Parents performed the role of buyers for their college going daughters' garments in most of the cases (63.33%) and the 73.33% girls had high level of satisfaction with this. In most of the cases (60%) the decision about the garment design was made by the girls themselves and they were highly satisfied with it. Keywords: clothing, college, girls, decision making.

Ecological Role of Exopolysaccharides of Bacillariophyta: A Review

2017 ◽  
Vol 19 (1) ◽  
pp. 5-24 ◽  
Author(s):  
E. I. Shnyukova ◽  
E. K. Zolotareva
Keyword(s):  
Ecological Role
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