scholarly journals Genomes of Strongylocentrotus franciscanus and Lytechinus variegatus: are there any genomic explanations for the two order of magnitude difference in the lifespan of sea urchins?

Aging ◽  
2016 ◽  
Vol 8 (2) ◽  
pp. 260-271 ◽  
Author(s):  
Petr V. Sergiev ◽  
Artem A. Artemov ◽  
Egor B. Prokhortchouk ◽  
Olga A. Dontsova ◽  
Grigory V. Berezkin
Keyword(s):  
Sea Urchins ◽  
Lytechinus Variegatus ◽  
Strongylocentrotus Franciscanus ◽  
Order Of Magnitude ◽  
Magnitude Difference

TEM Studies and Contact Resistance of Au/Ni/Ti/Ta/n-GaN Ohmic Contacts

2003 ◽  
Vol 764 ◽  
Author(s):  
D.N. Zakharov ◽  
Z. Liliental-Weber ◽  
A. Motayed ◽  
S.N. Mohammad
Keyword(s):  
Contact Resistance ◽  
Ohmic Contacts ◽  
High Resolution Electron Microscopy ◽  
X Ray ◽  
Electron Energy Loss Spectrometry ◽  
Resolution Electron ◽  
Order Of Magnitude ◽  
Contact Surfaces ◽  
Electron Energy Loss ◽  
Magnitude Difference

AbstractOhmic Ta/Ti/Ni/Au contacts to n-GaN have been studied using high resolution electron microscopy (HREM), energy dispersive X-ray spectrometry (EDX) and electron energy loss spectrometry (EELS). Two different samples were used: A - annealed at 7500C withcontact resistance 5×10-6 Ω cm2 and B-annealed at 7750C with contact resistance 6×10-5 Ω cm2. Both samples revealed extensive in- and out-diffusion between deposited layers with some consumption ofGaNlayerand formation of TixTa1-xN50 (0<x<25) at the GaN interface. Almost an order of magnitude difference in contact resistances can be attributed to structure and chemical bonding of Ti-O layers formed on the contact surfaces.

Social behaviour of juvenile red sea urchins, Strongylocentrotus franciscanus (Agassiz)

1985 ◽  
Vol 92 (1) ◽  
pp. 45-61 ◽  
Author(s):  
Paul A. Breen ◽  
Wolfgang Carolsfeld ◽  
K.Lynne Yamanaka
Keyword(s):  
Red Sea ◽  
Social Behaviour ◽  
Sea Urchins ◽  
Strongylocentrotus Franciscanus

Studies on Factors Affecting the Local Distribution of Two Sea Urchins, Arbacia Punctulata and Lytechinus Variegatus

Ecology ◽  
1962 ◽  
Vol 43 (2) ◽  
pp. 309 ◽  
Author(s):  
David T. Sharp ◽  
I. E. Gray
Keyword(s):  
Sea Urchins ◽  
Lytechinus Variegatus ◽  
Local Distribution ◽  
Factors Affecting ◽  
Arbacia Punctulata

Evaluating the temperature dependence of bedrock hillslope erosion in the Mont Blanc massif using in situ cosmogenic 3He-10Be-14C

2021 ◽  
Author(s):  
Donovan P. Dennis ◽  
Dirk Scherler ◽  
Samuel Niedermann ◽  
Kristina Hippe ◽  
Hella Wittmann ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Erosion Rates ◽  
Close Proximity ◽  
Order Of Magnitude ◽  
Stochastic Events ◽  
Exposure Ages ◽  
Alpine Environments ◽  
Magnitude Difference ◽  
Mont Blanc Massif

&lt;p&gt;The erosion of cold bedrock hillslopes in alpine environments depends not only on rates of frost weathering and accumulated rock damage, but additionally on the removal of the weathered material from the bedrock surface. In the Mont Blanc massif, steep bedrock faces with exposure ages sometimes much older than 50,000 years sit in close proximity to actively-eroding rockwalls, suggesting a more complex relationship between temperature and erosion rates than encompassed by the proposed &amp;#8220;frost-cracking window.&amp;#8221; Stochastic events like rockfalls and rock avalanches, despite their rarity, contribute a non-trivial proportion of the total sediment budget in alpine permafrost regions, adding to the contribution from background &amp;#8220;steady-state&amp;#8221; erosion. Employing a methodology based on the combination of in-situ cosmogenic nuclides &lt;sup&gt;3&lt;/sup&gt;He -&lt;sup&gt;10&lt;/sup&gt;Be-&lt;sup&gt;14&lt;/sup&gt;C, we test the temperature-dependence of high-alpine erosion while taking into account erosional stochasticity.&lt;/p&gt;&lt;p&gt;From cosmogenic &lt;sup&gt;10&lt;/sup&gt;Be concentrations of amalgamated samples collected on the Aiguille du Midi (3842 m a.s.l.) in the Mont Blanc massif, we find an order of magnitude difference in erosion rate across the peak&amp;#8217;s surface. Our preliminary measured erosion rates, ranging between appx. 0.03 mm yr&lt;sup&gt;-1&lt;/sup&gt; and 1.0 mm yr&lt;sup&gt;-1&lt;/sup&gt;, correlate neither with modern temperature measurements from borehole thermistors, nor with our current estimates of bedrock cosmogenic &lt;sup&gt;3&lt;/sup&gt;He-derived paleotemperatures. The corresponding cosmogenic &lt;sup&gt;14&lt;/sup&gt;C/&lt;sup&gt;10&lt;/sup&gt;Be ratios (between 1.70 and 4.0) for these erosion rates indicate that our measurements are not biased by recent stochastic rockfall events. Our current results therefore suggest that on geomorphic timescales, bedrock hillslope erosion rates are not set solely by rates of frost-cracking, but rather by the combined effects of frost-cracking and permafrost thaw-induced rockfalls. These insights are relevant both for short-term monitoring of alpine permafrost and associated geohazards under a warming climate, as well as studies of proposed &amp;#8220;buzzsaws&amp;#8221; operating on glacial-interglacial timescales.&lt;/p&gt;

Reproductive Success of Amnicola limosa (Gastropoda) in Low Alkalinity Lakes in South-Central Ontario

1989 ◽  
Vol 46 (5) ◽  
pp. 863-869 ◽  
Author(s):  
Margo A. Shaw ◽  
Gerald L. Mackie
Keyword(s):  
Life Cycle ◽  
Reproductive Success ◽  
Hatching Success ◽  
Low Ph ◽  
Critical Stage ◽  
Percent Survival ◽  
South Central ◽  
Order Of Magnitude ◽  
Magnitude Difference

The reproductive success of the gastropod Amnicola limosa was examined in six lakes ranging in pH from 4.62 to 7.42 to determine which stages in the life cycle were most sensitive to acidification. Although fecundity was significantly greater (p < 0.01) for adults reared at pH 7.42 than at pH 5.89–6.64, a failure to oviposit was documented only at pH 4.62. Hatching success was uniformly high (88–97%) at pH 5.59 to 7.42, while embryos incubated at pH 4.62 suffered complete mortality. The most critical stage in the life cycle is the newly hatched stage. Survival during the 20 d post hatch ranged from 23% at pH 5.59 to 69% at pH 7.42. There was an order of magnitude difference in the cumulative percent survival of recruits in lakes ranging in pH from 5.59 (5.1%) to 7.42 (44.0%). Juveniles raised at low pH (5.59–5.70) were on average 0.20 mm (20%) smaller than those in circumneutral lakes (pH 6.64–7.42). The present low densities of Amnicola limosa in Heney Lake (pH 5.59) can be explained by low recruitment since 1980. Evidence presented suggests that the disappearance of this species from clear low pH lakes (pH < 5.8) is due to reductions in fecundity and hatchling survival.

scholarly journals Improvement of Rainwater Infiltration Property and Its Effect on the Corresponding Storage Capacity of Soil in Urban Green Space

2018 ◽  
Vol 53 ◽  
pp. 04044
Author(s):  
LOU Keke ◽  
WU Zhengguang ◽  
LU Zhiping ◽  
KANG Aihong ◽  
YIN Chengsheng ◽  
...  
Keyword(s):  
Green Space ◽  
Peak Flow ◽  
Hydrological Cycle ◽  
Urban Green Space ◽  
Soil Permeability ◽  
Urban Green ◽  
Rainwater Infiltration ◽  
Cycle Plays ◽  
Order Of Magnitude ◽  
Magnitude Difference

Urban green space whose soil permeability is the main factor affecting hydrological cycle plays a very important role in promoting rainwater infiltration, replenishing groundwater and reducing peak flow. In order to enhance the storage and infiltration ability of soil, different types and contents of conditioner are added to study the laws of the changes in permeability of various soils. The results showed that straw and sawdust can effectively increase the permeability coefficient of soil. According to the comparison under the same conditions, the improvement effects of straw is slightly better than sawdust, but no order of magnitude difference. The sandy soil reformed by 3.6% Straw or 4.2% Sawdust and the loam reformed by 29.5% Straw or 30.2% Sawdust can meet infiltration requires of rainwater whose rainstorm recurrence period is 10 years. The clay is not suitable for urban green space soils with higher rainwater storage and infiltration requirements. The reformed green space can effectively reduce the runoff peak flow and delay the generated time of the runoff. The higher the content of the modifier, the more obvious the advantage of promoting the hydrological cycle and reducing the runoff.

scholarly journals Chronic toxicity test with sea urchin Echinometra lucunter and Lytechinus variegatus (Echinodermata: Echinoidea), exposed to light-stick - flag paternoster used for longline surface fishing

2010 ◽  
Vol 58 (spe3) ◽  
pp. 71-75 ◽  
Author(s):  
Caio Cesar-Ribeiro ◽  
Maria Fernanda Palanch-Hans
Keyword(s):  
Toxicity Test ◽  
Chronic Toxicity ◽  
Sea Water ◽  
Sea Urchins ◽  
Preliminary Test ◽  
Lytechinus Variegatus ◽  
Confidence Limits ◽  
Potential Danger ◽  
Final Test ◽  
Chronic Toxicity Test

In this work, the chronic toxicity of a mixture of light-stick chemicals and water was tested. The light-stick is used in fishery activities to catch swordfish. The tubes were collected on the beaches of the Costa dos Coqueiros - BA, Brazil, in the period from 14th to 31st July 2007. The method used was a short chronic toxicity test where embryos of the sea urchins Echinometra lucunter and Lytechinus variegatus were exposed to a stock solution consisting of the supernatant formed from a mixture of sea water and the orange-colored light-stick chemical. After a preliminary test, concentrations defined were 0.002, 0.003, 0.01, 0.02, 0.1, 1.0% of stock solution. The final test ran for 36 hours for E. Lucunter and 24 hours for L. variegatus with 4 replicates for each concentration. The value of EC50 - 36h was 0.062% with confidence limits ranging from 0.042 to 0.079% and the EC50 - 24h was 0.011% with confidence limits ranging from 0.009 to 0.014%, i.e., the chemical mix present in the light-stick is potentially toxic. So, as these flags are commonly used for fishing there is potential danger in their disposal in the open ocean.

Genetic heterogeneity among adult and recruit red sea urchins, Strongylocentrotus franciscanus

2000 ◽  
Vol 136 (5) ◽  
pp. 773-784 ◽  
Author(s):  
P. E. Moberg ◽  
R. S. Burton
Keyword(s):  
Red Sea ◽  
Genetic Heterogeneity ◽  
Sea Urchins ◽  
Strongylocentrotus Franciscanus

Spent Nuclear Fuel Radiotoxicity Evaluation in the Context of Minor Actinides Management With ADS Systems

2008 ◽  
Author(s):  
Barbara Vezzoni ◽  
Barbara Calgaro ◽  
Nicola Cerullo ◽  
Giuseppe Forasassi
Keyword(s):  
Spent Nuclear Fuel ◽  
Reference Level ◽  
Minor Actinides ◽  
Critical Approach ◽  
Nuclear Facilities ◽  
Computational Tools ◽  
Qualitative And Quantitative ◽  
Order Of Magnitude ◽  
Definition Of ◽  
Magnitude Difference

The most effective way to reduce the time to reach a radiotoxicity reference level is, probably, the transmutation of Minor Actinides with fast fission processes. The definition of a critical approach to justify GEN.IV nuclear facilities, as minor actinides transmuters, is the main topic of this work. In this direction, firstly the evaluation of the reference level best estimation was performed, followed by the qualitative and quantitative radiotoxicity evolution in the ICRP Recommendations, their impact on P&T chosen strategy and on US and European rules in order to preliminarily analyze industrial ADS burning capability. Computational tools used are MCNPX-2.5.0 and ORIGEN-2.2 codes in synergy with the state of art of internal dosimetry in ICRP Publications, 10 CFR Part.20 and 96/29/EURATOM. One order of magnitude difference between the radiotoxicity evaluated by the 10 CFR Part.20 (1994) coefficients and the radiotoxicity evaluated by the actual European rules coefficients was identified.

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