Portable PIT detector as a new tool for non-disruptively locating individually tagged amphibians in the field: a case study with Pyrenean brook salamanders (Calotriton asper)

2008 ◽  
Vol 35 (8) ◽  
pp. 780 ◽  
Author(s):  
J. Cucherousset ◽  
P. Marty ◽  
L. Pelozuelo ◽  
J.-M. Roussel
Keyword(s):  
Shallow Waters ◽  
Passive Integrated Transponder ◽  
Capture Method ◽  
The Mean ◽  
Portable Detector ◽  
Pit Telemetry

Passive Integrated Transponder (PIT) telemetry has recently been adapted for locating PIT-tagged fish in shallow waters using portable detectors. In the present study, we tested this method for adult amphibians (Pyrenean brook salamanders, Calotriton asper) PIT-tagged with 12-mm transponders in a headwater rocky stream. PIT telemetry performances were compared with a conventional hand-capture method, i.e. visual searching and overturning movable stones in the streambed. The mean efficiency of the portable detector (88.2% ± 5.2, s.e.) was significantly higher than hand-capture (51.1% ± 6.4) and the operator progressed, on average, four times faster. Time efficiencies were, on average, 0.92 (±0.15) and 0.12 (±0.04) adult salamanders per minute with the portable detector and by hand-capture, respectively. The efficiency of the portable detector was negatively correlated with the percentage of large stones on the streambed. The time needed to prospect a section was positively correlated with the abundance of PIT-tagged adult salamanders, spring inlets and undercut banks. Because PIT telemetry is less disruptive than hand-capture for both salamanders and their habitat, it is a promising and non-disruptive method for developing studies on the ecology and management of amphibians in shallow waters.

Movement patterns of the invasive signal crayfish determined by PIT telemetry

2006 ◽  
Vol 84 (8) ◽  
pp. 1202-1209 ◽  
Author(s):  
Damian H. Bubb ◽  
Timothy J. Thom ◽  
Martyn C. Lucas
Keyword(s):  
Space Use ◽  
Field Studies ◽  
Remote Detection ◽  
Signal Crayfish ◽  
Passive Integrated Transponder ◽  
Median Distance ◽  
Release Location ◽  
Density Population ◽  
Portable Detector ◽  
Pit Telemetry

In one of the first field studies to utilize passive integrated transponder (PIT) telemetry to study space use of invertebrates, movement of the introduced signal crayfish ( Pacifastacus leniusculus (Dana, 1852)) was examined intensively in a high-density population in an upland river in northern England from 18 August to 6 September 2004. Crayfish (carapace length 21.0–67.3 mm) were tracked with externally attached PIT tags, enabling remote detection of tagged crayfish by the use of a portable detector. Of the 406 crayfish tagged, 356 (87.7%) were subsequently relocated at least once. The majority of crayfish remained close to the release location (median distance between release and final locations 36.3 m; 25th percentile 10.4 m, 75th percentile 91.6 m). However, movements of up to 345 m were recorded. There was no relationship between sex or size and distance moved. A small waterfall, upstream of the release location, appeared to form a barrier preventing movements of tagged crayfish upstream past it during the study period. PIT telemetry can provide an effective method for detailed recording of space use compared with standard mark–recapture or radiotelemetry methods.

scholarly journals Factors Influencing Smallholder Crop Diversification: A Case Study of Manicaland and Masvingo Provinces in Zimbabwe

2016 ◽  
Vol 3 (2) ◽  
pp. 1 ◽  
Author(s):  
Lighton Dube
Keyword(s):  
Smallholder Farmers ◽  
Diversity Index ◽  
Tobit Model ◽  
Crop Diversification ◽  
Factors Associated ◽  
Head Of Household ◽  
The Mean ◽  
Female Headed Households ◽  
Extension Support

<p>This study analyzes the degree of crop diversification and factors associated with crop diversification among 479 smallholder farmers in Manicaland and Masvingo provinces of Zimbabwe. The Herfindahl index used to estimate diversification, while the Tobit model evaluated factors associated with crop diversification.  The mean crop diversity index is 0.54. On average households in Nyanga and Bikita are the most diversified with indices of 0.48 and 0.49 respectively. The most specialized households are in Mutasa and Chiredzi with indices of 0.62. An analysis by gender shows that male headed households are slightly more diversified than female headed households. The Tobit model indicates that gender of head of household, education, number of livestock units, access to irrigation, membership to a farmers group, access to markets, farming experience, farms on flat terrain, farmer to farm extension, routine extension, agro-ecological zone and household income are significant contributors to increasing crop diversification. In turn, crop specialization is significantly associated with off-farm employment, soil fertility, farmers who are happy with extension contacts per year, farmers trained using the farmer field school approach and farmers who receive NGO extension support.</p>

scholarly journals Heavy Metals in Water and Sediment: A Case Study of Tembi River

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Saeed Shanbehzadeh ◽  
Marzieh Vahid Dastjerdi ◽  
Akbar Hassanzadeh ◽  
Toba Kiyanizadeh
Keyword(s):  
Heavy Metals ◽  
Drinking Water ◽  
Average Concentration ◽  
Agricultural Water ◽  
Water And Sediment ◽  
The Mean ◽  
Mean Concentration ◽  
Cu And Zn ◽  
Standard Range

This study was carried out to examine heavy metals concentration in water and sediment of upstream and downstream of the entry of the sewage to the Tembi River, Iran. Samples were collected from upstream and downstream and were analyzed for Cd, Cr, Cu, Fe, Pb, Ni, and Zn by atomic absorption spectrophotometer. The results indicated that the average concentration of the metals in water and sediment on downstream was more than that of upstream. The comparison of the mean concentrations of heavy metals in water of the Tembi River with drinking water standards and those in the water used for agriculture suggests that the mean concentration of Cu and Zn lies within the standard range for drinking water and the mean concentration of Mn, Zn, and Pb lies within the standard range of agricultural water. The highest average concentration on downstream for Pb in water and for Mn in sediment was 1.95 and 820.5 ppm, respectively. Also, the lowest average concentration on upstream was identified for Cd in water and sediment 0.07 and 10 ppm, respectively. With regard to the results, it gets clear that using the water for recreational purposes, washing, and fishing is detrimental to human health and the environment.

scholarly journals Illusory Depth Based on Interactions Between Fluorescent and Conventional Colours: A Case Study on Frank Stella’s Irregular Polygons Paintings

2018 ◽  
Vol 6 (2-3) ◽  
pp. 116-150
Author(s):  
Stefanie De Winter ◽  
Pieter Moors ◽  
Hilde Van Gelder ◽  
Johan Wagemans
Keyword(s):  
Contrast Effects ◽  
Depth Effect ◽  
Historical Significance ◽  
Art Historians ◽  
Correct Reading ◽  
The Subject ◽  
The Mean

Although Frank Stella intended to create flat, illusion-less Irregular Polygons paintings, it is not uncommon to experience the illusion of colour depth, based on the interaction between their fluorescent and conventional colours. Some critics praised these artworks’ flatness, while others described odd depth experiences that they categorised as a new kind of illusion. In order to provide a correct reading of these works and to reassess their art historical significance, a scientific case study regarding this colour-depth effect imposes itself. This article discusses an experiment in which we determined whether twenty artists, twenty art historians and twenty laypeople experienced fluorescent colours as protruding, receding or flat in combination with conventional colours. We additionally looked at whether they still perceived colour depth when all fluorescent colours were replaced with their conventional variants. All participants observed fifteen designs, which they had to rate according to the perceived depth of each coloured region with a number between −3 (strongly receding) and +3 (strongly protruding). The results revealed that most participants experience fluorescent regions as strongly protruding, unlike all conventional colours, which were rated as much less protruding. When a fluorescent colour was swapped with a conventional variant, all participants experienced significantly less depth. The differences between the subject groups were statistically negligible when looking at the mean depth ratings for both colour types. However, we discovered that artists experienced more contrast effects, as they gave different ratings to different panels (of identical colour and shape) in the same design, depending on their position.

scholarly journals A case study of the plasma in the magneto-sheath using the numerical magnetosheath-magnetosphere model and THEMIS measure-ments

2018 ◽  
Vol 145 ◽  
pp. 03004
Author(s):  
Polya Dobreva ◽  
Olga Nitcheva ◽  
Monio Kartalev
Keyword(s):  
Magnetic Field ◽  
Field Model ◽  
Specific Aspect ◽  
Plasma Parameters ◽  
Ion Density ◽  
Magnetic Field Model ◽  
Wind Spacecraft ◽  
The Mean ◽  
The Magnetic Field

This paper presents a case study of the plasma parameters in the magnetosheath, based on THEMIS measurements. As a theoretical tool we apply the self-consistent magnetosheath-magnetosphere model. A specific aspect of the model is that the positions of the bow shock and the magnetopause are self-consistently determined. In the magnetosheath the distribution of the velocity, density and temperature is calculated, based on the gas-dynamic theory. The magnetosphere module allows for the calculation of the magnetopause currents, confining the magnetic field into an arbitrary non-axisymmetric magnetopause. The variant of the Tsyganenko magnetic field model is applied as an internal magnetic field model. As solar wind monitor we use measurements from the WIND spacecraft. The results show that the model quite well reproduces the values of the ion density and velocity in the magnetosheath. The simlicity of the model allows calulations to be perforemed on a personal computer, which is one of the mean advantages of our model.

scholarly journals Fuel economy assessment tool for auxiliary kite propulsion of merchant ship

2018 ◽  
pp. 5-7 ◽  
Author(s):  
Vincent Podeur ◽  
Damien Merdrignac ◽  
Morgan Behrel ◽  
Kostia Roncin ◽  
Caroline Fonti ◽  
...  
Keyword(s):  
Fuel Economy ◽  
Assessment Tool ◽  
Round Trip ◽  
Merchant Ship ◽  
Added Resistance In Waves ◽  
The Mean ◽  
The Impact ◽  
Engine Power

A tool dedicated to assess fuel economy induced by kite propulsion has been developed. To produce reliable results, computations must be performed on a period over several years, for several routes and for several ships. In order to accurately represent the impact of meteorological trends variations on the exploitability of the kite towing concept, a time domain approach of the problem has been used. This tool is based on the weather database provided by the ECMWF. Two sailing strategies can be selected for assessing the performance of the kite system. For a given kite area, the simulation can be run either at constant speed or at constant engine power. A validation has been made, showing that predicted consumption is close from in-situ measurement. It shows an underestimation of 11.9% of the mean fuel consumption mainly due to auxiliary consumption and added resistance in waves that were not taken into account. To conclude, a case study is performed on a 2200 TEU container ship equipped with an 800m² kite on a transatlantic route between Halifax and Le Havre. Round trip simulations, performed over 5 years of navigation, show that the total economy predicted is of around 12% at a speed of 16 knots and around 6.5% at a speed of 19 knots.

scholarly journals Estimation of Above-Ground Mangrove Biomass Using Landsat-8 Data- Derived Vegetation Indices: A Case Study in Quang Ninh Province, Vietnam

2021 ◽  
pp. 506-525
Author(s):  
Hai-Hoa Nguyen ◽  
Huy Duc Vu ◽  
Achim Röder
Keyword(s):  
Vegetation Indices ◽  
Landsat 8 ◽  
Mangrove Forests ◽  
Estimation Model ◽  
The Status ◽  
Good Potential ◽  
The Mean ◽  
Accuracy Assessments ◽  
Quang Ninh

This study aimed to map the status of mangrove forests over the coasts of Hai Ha District and Mong Cai City in Quang Ninh Province by using 2019 Landsat-8 imagery. It then developed the AGB estimation model of mangrove forests based on the AGB estimation-derived plots inventory and vegetation indices-derived from Landsat-8 data. As results, there were five land covers identified, including mangrove forests, other vegetation, wetlands, built-up, and water, with the overall accuracy assessments of 80.0% and Kappa coefficient of 0.74. The total extent of mangrove forests was estimated at 4291.2 ha. The best AGB estimation model that was selected to estimate the AGB and AGC of mangrove forests for the whole coasts of Hai Ha District and Mong Cai City is AGB= 30.38 + 911.95*SAVI (R2=0.924, PValue <0.001). The model validation assessment has confirmed that the selected AGB model can be applied to Hai Ha and Mong Cai coasts with the mean difference between AGB observed and AGB predicted at 16.0 %. This satisfactory AGB model also suggests a good potential for AGB and AGC mapping, which offer the carbon trading market in the study site. As the AGB model selected, the total AGB and AGC of mangrove forests were estimated at about 14,600,000 tons and 6,868,076 tons with a range of from 94.0 - 432.0 tons ha-1, from 44.2 - 203.02 tons ha-1, respectively. It also suggests that the newly-developed AGB model of mangrove forests can be used to estimate AGC stocks and carbon sequestration of mangrove forests for C-PFES in over the coasts of Hai Ha District and Mong Cai City, which is a very importantly financial source for mangrove forest managers, in particular for local mangrove protectors.

scholarly journals SUBTYPE COASTLINE DETERMINATION IN URBAN COAST BASED ON MULTISCALE FEATURES: A CASE STUDY IN TIANJIN, CHINA

2018 ◽  
Vol XLII-3 ◽  
pp. 1565-1570
Author(s):  
Y. Song ◽  
Y. Ai ◽  
H. Zhu
Keyword(s):  
Urban Growth ◽  
Misclassification Error ◽  
Ecological Environment ◽  
Landsat Thematic Mapper ◽  
Crucial Importance ◽  
Scale Invariant ◽  
Coastal City ◽  
Feature Based ◽  
The Mean

In urban coast, coastline is a direct factor to reflect human activities. It is of crucial importance to the understanding of urban growth, resource development and ecological environment. Due to complexity and uncertainty in this type of coast, it is difficult to detect accurate coastline position and determine the subtypes of the coastline. In this paper, we present a multiscale feature-based subtype coastline determination (MFBSCD) method to extract coastline and determine the subtypes. In this method, uncertainty-considering coastline detection (UCCD) method is proposed to separate water and land for more accurate coastline position. The MFBSCD method can well integrate scale-invariant features of coastline in geometry and spatial structure to determine coastline in subtype scale, and can make subtypes verify with each other during processing to ensure the accuracy of final results. It was applied to Landsat Thematic Mapper (TM) and Operational Land Imager (OLI) images of Tianjin, China, and the accuracy of the extracted coastlines was assessed with the manually delineated coastline. The mean ME (misclassification error) and mean LM (Line Matching) are 0.0012 and 24.54&amp;thinsp;m respectively. The method provides an inexpensive and automated means of coastline mapping with subtype scale in coastal city sectors with intense human interference, which can be significant for coast resource management and evaluation of urban development.

scholarly journals Towards an objective assessment of climate multi-model ensembles – a case study: the Senegalo-Mauritanian upwelling region

2020 ◽  
Vol 13 (6) ◽  
pp. 2723-2742
Author(s):  
Juliette Mignot ◽  
Carlos Mejia ◽  
Charles Sorror ◽  
Adama Sylla ◽  
Michel Crépon ◽  
...  
Keyword(s):  
Numerical Models ◽  
Objective Assessment ◽  
Cmip5 Models ◽  
Model Ensemble ◽  
Self Organizing Maps ◽  
Climate Simulations ◽  
Mean Sea Surface ◽  
The Mean ◽  
Model Ensembles

Abstract. Climate simulations require very complex numerical models. Unfortunately, they typically present biases due to parameterizations, choices of numerical schemes, and the complexity of many physical processes. Beyond improving the models themselves, a way to improve the performance of the modeled climate is to consider multi-model combinations. In the present study, we propose a method to select the models that yield a multi-model ensemble combination that efficiently reproduces target features of the observations. We used a neural classifier (self-organizing maps), associated with a multi-correspondence analysis to identify the models that best represent some target climate property. We can thereby determine an efficient multi-model ensemble. We illustrated the methodology with results focusing on the mean sea surface temperature seasonal cycle in the Senegalo-Mauritanian region. We compared 47 CMIP5 model configurations to available observations. The method allows us to identify a subset of CMIP5 models able to form an efficient multi-model ensemble. The future decrease in the Senegalo-Mauritanian upwelling proposed in recent studies is then revisited using this multi-model selection.

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