scholarly journals Use of a high resolution magnetic map by a short distance migrant, the alpine newt (Ichthyosaura alpestris)?

2021 ◽  
Author(s):  
Francisco J. Diego-Rasilla ◽  
John B. Phillips
Keyword(s):  
Temporal Variation ◽  
Light Exposure ◽  
Time Of Day ◽  
Magnetic Compass ◽  
Diffuse Illumination ◽  
Order Of Magnitude ◽  
Testing Site ◽  
Alpine Newt ◽  
A Site ◽  
Ichthyosaura Alpestris

Newts can use spatial variation in the magnetic field (MF) to derive geographic position, but it is unclear how they detect the ‘spatial signal’ which, over the distances that newts move in a day, is an order of magnitude lower than temporal variation in the MF. Newts take map readings using their light-dependent magnetic compass to align a magnetite-based ‘map detector’ relative to the MF. Time-of-day, location, and light exposure (required by the magnetic compass) were varied to determine when newts obtain map information. Newts were displaced from breeding ponds without access to route-based cues to sites where they were held and/or tested under diffuse natural illumination. We found that: (1) newts held overnight at the testing site under diffuse illumination exhibited accurate homing orientation, but not if transported to the testing site on the day of testing, (2) newts held overnight under diffuse lighting at a ‘false testing site’ and then tested at a site located in a different direction from their home pond, oriented in the home direction from the holding site, not from the site where they were tested, (3) newts held overnight in total darkness (except for light exposure for specific periods) only exhibited homing orientation the following day if exposed to diffuse illumination during the preceding evening twilight in the ambient MF. These findings demonstrate that, to determine the home direction, newts require access to light and the ambient MF during evening twilight when temporal variation in the MF is minimal.

scholarly journals The effects of short-term light exposure on subjective affect and comfort are dependent on the lighting time of day

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lijun Chen ◽  
Fang-Fang Yan ◽  
Shuhan Fan ◽  
Yifan Wu ◽  
Jia Yang ◽  
...  
Keyword(s):  
Significant Role ◽  
Negative Correlation ◽  
Significant Interaction ◽  
Daily Life ◽  
Light Exposure ◽  
Time Of Day ◽  
Color Temperature ◽  
Subjective Feeling ◽  
Short Term ◽  
Illuminance Level

AbstractLight, one of the key environmental components for both life and work, played significant role in subjective feelings (e.g. affect and comfort), but the exact effects and mechanisms were still to be determined. The present study screened thirty healthy adults (13 females, 22.45 ± 3.26 years) and examined subjective affect and comfort under short-term white lights with different combination of correlated color temperature (CCT) and illuminance at different times of day (e.g. morning, afternoon, and evening). Our results showed a significant interaction between illuminance level and time-of-day on subjective comfort. Participants felt more comfortable under 50 lx and 100 lx instead of 500 lx in the evening, and more comfortable under 500 lx in the morning and afternoon. In addition, a positive correlation between illuminance and comfort in the morning and a negative correlation between them in the evening were found. No significant effect of CCT on any subjective feeling was revealed. Our results necessitate the consideration of time-of-day in understanding lighting effects and application of healthy lighting in daily life.

Temporal variation of suspended particles (TSP, PM10, and PM2.5) and chemical composition of PM10 in a site at the coast of the Gulf of Mexico

2019 ◽  
Vol 12 (11) ◽  
pp. 1267-1277 ◽  
Author(s):  
Alberto A. Espinosa ◽  
Javier Miranda ◽  
Enrique Hernández ◽  
Javier Reyes ◽  
Ana L. Alarcón ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Gulf Of Mexico ◽  
Temporal Variation ◽  
Suspended Particles ◽  
Pm10 And Pm2.5 ◽  
A Site

scholarly journals Using the SWEPT Methodology for a Preliminary Wind Potential Estimation

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Jean-Luc Menet
Keyword(s):  
Wind Turbine ◽  
Characteristic Curve ◽  
Rayleigh Distribution ◽  
Mean Velocity ◽  
Technical Data ◽  
Wind Potential ◽  
Order Of Magnitude ◽  
General Data ◽  
The Mean ◽  
A Site

The implantation of wind turbines generally follows a wind potential study which is made using specific numerical tools; the generated expenses are only acceptable for great projects. The purpose of the present paper is to propose a simplified methodology for the evaluation of the wind potential, following three successive steps for the determination of (i) the mean velocity, either directly or by the use of the most occurrence velocity (MOV); (ii) the velocity distribution coming from the single knowledge of the mean velocity by the use of a Rayleigh distribution and a Davenport-Harris law; (iii) an appropriate approximation of the characteristic curve of the turbine, coming from only two technical data. These last two steps allow calculating directly the electric delivered energy for the considered wind turbine. This methodology, called the SWEPT approach, can be easily implemented in a single worksheet. The results returned by the SWEPT tool are of the same order of magnitude than those given by the classical commercial tools. Moreover, everybody, even a “neophyte,” can use this methodology to obtain a first estimation of the wind potential of a site considering a given wind turbine, on the basis of very few general data.

scholarly journals Carbaryl Photochemical Degradation on Soil Model Surfaces

Soil Systems ◽  
2019 ◽  
Vol 3 (1) ◽  
pp. 17 ◽  
Author(s):  
Marie Siampiringue ◽  
Rajae Chahboune ◽  
Pascal Wong-Wah-Chung ◽  
Mohamed Sarakha
Keyword(s):  
Liquid Chromatography ◽  
Light Exposure ◽  
Degradation Mechanism ◽  
Parent Compound ◽  
Toxicity Tests ◽  
Photochemical Degradation ◽  
First Order Kinetics ◽  
A Value ◽  
Order Of Magnitude ◽  
Set Up

The phototransformation of carbaryl was investigated upon solar light exposure on three surfaces, silica, kaolin and sand, as soil models. By excitation with a Suntest set up at the surface of the three solid supports, the degradation of carbaryl followed first-order kinetics with a rate constant of 0.10 h−1. By using the Kubelka Munk model, the quantum yield disappearance at the surface of kaolin was evaluated to 2.4 × 10−3. Such a value is roughly one order of magnitude higher than that obtained in aqueous solutions. The results indicated that the particle size and the specific surface area of the various models have significant effects. The photo-oxidative properties as well as the byproduct elucidation by liquid chromatography combined with diode arrays (LC-DAD) and liquid chromatography coupled mass spectrometry (LC-MS) analyses allowed us to propose the degradation mechanism pathways. The main products were 1-naphtol and 2-hydroxy-1,4-naphthoquinone, which arise from a photo-oxidation process together with products from photo-Fries, photo-ejection and methyl carbamate hydrolysis. The toxicity tests clearly showed a significant decrease of the toxicity in the early stages of the irradiation. This clearly shows that the generated products are less toxic than the parent compound.

scholarly journals Biases in Thorpe-Scale Estimates of Turbulence Dissipation. Part I: Assessments from Large-Scale Overturns in Oceanographic Data

2015 ◽  
Vol 45 (10) ◽  
pp. 2497-2521 ◽  
Author(s):  
Benjamin D. Mater ◽  
Subhas K. Venayagamoorthy ◽  
Louis St. Laurent ◽  
James N. Moum
Keyword(s):  
Large Scale ◽  
Companion Paper ◽  
Open Ocean ◽  
Luzon Strait ◽  
Length Scale ◽  
Ensemble Averaging ◽  
Tidal Period ◽  
Thorpe Scale ◽  
Order Of Magnitude ◽  
A Site

AbstractOceanic density overturns are commonly used to parameterize the dissipation rate of turbulent kinetic energy. This method assumes a linear scaling between the Thorpe length scale LT and the Ozmidov length scale LO. Historic evidence supporting LT ~ LO has been shown for relatively weak shear-driven turbulence of the thermocline; however, little support for the method exists in regions of turbulence driven by the convective collapse of topographically influenced overturns that are large by open-ocean standards. This study presents a direct comparison of LT and LO, using vertical profiles of temperature and microstructure shear collected in the Luzon Strait—a site characterized by topographically influenced overturns up to O(100) m in scale. The comparison is also done for open-ocean sites in the Brazil basin and North Atlantic where overturns are generally smaller and due to different processes. A key result is that LT/LO increases with overturn size in a fashion similar to that observed in numerical studies of Kelvin–Helmholtz (K–H) instabilities for all sites but is most clear in data from the Luzon Strait. Resultant bias in parameterized dissipation is mitigated by ensemble averaging; however, a positive bias appears when instantaneous observations are depth and time integrated. For a series of profiles taken during a spring tidal period in the Luzon Strait, the integrated value is nearly an order of magnitude larger than that based on the microstructure observations. Physical arguments supporting LT ~ LO are revisited, and conceptual regimes explaining the relationship between LT/LO and a nondimensional overturn size are proposed. In a companion paper, Scotti obtains similar conclusions from energetics arguments and simulations.

Magnetic compass mediates nocturnal homing by the alpine newt, Triturus alpestris

2005 ◽  
Vol 58 (4) ◽  
pp. 361-365 ◽  
Author(s):  
Francisco J. Diego-Rasilla ◽  
Rosa M. Luengo ◽  
John B. Phillips
Keyword(s):  
Magnetic Compass ◽  
Triturus Alpestris ◽  
Alpine Newt

scholarly journals Observations of nonmethane organic compounds during ARCTAS − Part 1: Biomass burning emissions and plume enhancements

2011 ◽  
Vol 11 (21) ◽  
pp. 11103-11130 ◽  
Author(s):  
R. S. Hornbrook ◽  
D. R. Blake ◽  
G. S. Diskin ◽  
A. Fried ◽  
H. E. Fuelberg ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Biomass Burning ◽  
Source Region ◽  
Measurement Techniques ◽  
Proton Transfer Reaction ◽  
Time Of Day ◽  
The Arctic ◽  
Mixing Ratios ◽  
Order Of Magnitude ◽  
Good Agreement

Abstract. Mixing ratios of a large number of nonmethane organic compounds (NMOCs) were observed by the Trace Organic Gas Analyzer (TOGA) on board the NASA DC-8 as part of the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) field campaign. Many of these NMOCs were observed concurrently by one or both of two other NMOC measurement techniques on board the DC-8: proton-transfer-reaction mass spectrometry (PTR-MS) and whole air canister sampling (WAS). A comparison of these measurements to the data from TOGA indicates good agreement for the majority of co-measured NMOCs. The ARCTAS study, which included both spring and summer deployments, provided opportunities to sample a large number of biomass burning (BB) plumes with origins in Asia, California and central Canada, ranging from very recent emissions to plumes aged one week or more. For this analysis, BB smoke interceptions were grouped by flight, source region and, in some cases, time of day, generating 40 identified BB plumes for analysis. Normalized excess mixing ratios (NEMRs) to CO were determined for each of the 40 plumes for up to 19 different NMOCs or NMOC groups. Although the majority of observed NEMRs for individual NMOCs or NMOC groups were in agreement with previously-reported values, the observed NEMRs to CO for ethanol, a rarely quantified gas-phase trace gas, ranged from values similar to those previously reported, to up to an order of magnitude greater. Notably, though variable between plumes, observed NEMRs of individual light alkanes are highly correlated within BB emissions, independent of estimated plume ages. BB emissions of oxygenated NMOC were also found to be often well-correlated. Using the NCAR Master Mechanism chemical box model initialized with concentrations based on two observed scenarios, fresh Canadian BB and fresh Californian BB, decreases are predicted for the low molecular weight carbonyls (i.e. formaldehyde, acetaldehyde, acetone and methyl ethyl ketone, MEK) and alcohols (i.e. methanol and ethanol) as the plumes evolve in time, i.e. the production of these compounds is less than the chemical loss. Comparisons of the modeled NEMRs to the observed NEMRs from BB plumes estimated to be three days in age or less indicate overall good agreement.

scholarly journals Circadian Photoentrainment in Mice and Humans

Biology ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 180
Author(s):  
Russell G. Foster ◽  
Steven Hughes ◽  
Stuart N. Peirson
Keyword(s):  
Ganglion Cells ◽  
Light Exposure ◽  
Bright Light ◽  
Functional Expression ◽  
Time Of Day ◽  
High Irradiance ◽  
Intermittent Light ◽  
Long Duration ◽  
Light History

Light around twilight provides the primary entrainment signal for circadian rhythms. Here we review the mechanisms and responses of the mouse and human circadian systems to light. Both utilize a network of photosensitive retinal ganglion cells (pRGCs) expressing the photopigment melanopsin (OPN4). In both species action spectra and functional expression of OPN4 in vitro show that melanopsin has a λmax close to 480 nm. Anatomical findings demonstrate that there are multiple pRGC sub-types, with some evidence in mice, but little in humans, regarding their roles in regulating physiology and behavior. Studies in mice, non-human primates and humans, show that rods and cones project to and can modulate the light responses of pRGCs. Such an integration of signals enables the rods to detect dim light, the cones to detect higher light intensities and the integration of intermittent light exposure, whilst melanopsin measures bright light over extended periods of time. Although photoreceptor mechanisms are similar, sensitivity thresholds differ markedly between mice and humans. Mice can entrain to light at approximately 1 lux for a few minutes, whilst humans require light at high irradiance (>100’s lux) and of a long duration (>30 min). The basis for this difference remains unclear. As our retinal light exposure is highly dynamic, and because photoreceptor interactions are complex and difficult to model, attempts to develop evidence-based lighting to enhance human circadian entrainment are very challenging. A way forward will be to define human circadian responses to artificial and natural light in the “real world” where light intensity, duration, spectral quality, time of day, light history and age can each be assessed.

scholarly journals Distribution of the alpine newt Ichthyosaura alpestris in Great Britain updated using social media

2021 ◽  
pp. 28-31
Author(s):  
Steven J.R. Allain
Keyword(s):  
Social Media ◽  
Great Britain ◽  
Alien Species ◽  
New Records ◽  
Location Information ◽  
Distribution Map ◽  
Map Comparison ◽  
Alpine Newt ◽  
Ichthyosaura Alpestris

The alpine newt (Ichthyosaura alpestris) is an alien species in Great Britain. Using location information derived from photographs posted on social media we have updated its known distribution, validated previously unconfirmed populations, and present an updated distribution map. Comparison of the records collected from social media with those in the National Biodiversity Network Atlas indicates eleven new confirmed populations, although three of these had previously been shown as unconfirmed records in the NBN Atlas. The new records have been deposited with NBN.

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