scholarly journals Honeybees use absolute rather than relative numerosity in number discrimination

2019 ◽  
Vol 15 (6) ◽  
pp. 20190138 ◽  
Author(s):  
Maria Bortot ◽  
Christian Agrillo ◽  
Aurore Avarguès-Weber ◽  
Angelo Bisazza ◽  
Maria Elena Miletto Petrazzini ◽  
...  
Keyword(s):  
Absolute Number ◽  
Vertebrate Species ◽  
Numerical Ability ◽  
Basic Properties ◽  
Number Discrimination ◽  
Ratio Dependent ◽  
Better Than

Various vertebrate species use relative numerosity judgements in comparative assessments of quantities for which they use larger/smaller relationships rather than absolute number. The numerical ability of honeybees shares basic properties with that of vertebrates but their use of absolute or relative numerosity has not been explored. We trained free-flying bees to choose variable images containing three dots; one group (‘larger’) was trained to discriminate 3 from 2, while another group (‘smaller’) was trained to discriminate 3 from 4. In both cases, numbers were kept constant but stimulus characteristics and position were varied from trial to trial. Bees were then tested with novel stimuli displaying the previously trained numerosity (3) versus a novel numerosity (4 for ‘larger’ and 2 for ‘smaller’). Both groups preferred the three-item stimulus, consistent with absolute numerosity. They also exhibited ratio-dependent discrimination of numbers, a property shared by vertebrates, as performance after 2 versus 3 was better than after 3 versus 4 training. Thus, bees differ from vertebrates in their use of absolute rather than of relative numerosity but they also have some numeric properties in common.

scholarly journals Use it or lose it: measuring trends in wild species subject to substantial use

Oryx ◽  
2014 ◽  
Vol 48 (3) ◽  
pp. 420-429 ◽  
Author(s):  
Megan Tierney ◽  
Rosamunde Almond ◽  
Damon Stanwell-Smith ◽  
Louise McRae ◽  
Christoph Zöckler ◽  
...  
Keyword(s):  
Sustainable Use ◽  
Biodiversity Loss ◽  
Future Generations ◽  
The Arctic ◽  
Vertebrate Species ◽  
Global Level ◽  
Sustainable Harvest ◽  
Sample Data ◽  
Harvest Sustainability ◽  
Better Than

AbstractThe unsustainable use of wild animals and plants is thought to be a significant driver of biodiversity loss in many regions of the world. The international community has therefore called for action to ensure the sustainable use of living resources and safeguard them for future generations. Indicators that can track changes in populations of species used by humans are essential tools for measuring progress towards these ideals and informing management decisions. Here we present two indicators that could be used to track changes in populations of utilized vertebrate species and levels of harvest sustainability. Preliminary results based on sample data both at the global level and for the Arctic show that utilized species are faring better than other species overall. This could be a consequence of better management of these populations, as indicated by more sustainable harvest levels in recent decades. Limitations of the indicators are still apparent; in particular, there is a lack of data on harvested populations of some vertebrate classes and from certain regions. Focusing monitoring efforts on broadening the scope of data collected and identifying interactions with other potential drivers of decline will strengthen these indicators as policy tools and improve their potential to be incorporated into future sets of indicators to track progress towards global biodiversity targets.

A High-Speed Analogue Multiplier

SIMULATION ◽  
1964 ◽  
Vol 3 (1) ◽  
pp. 58-62
Keyword(s):  
High Speed ◽  
The Other ◽  
Wave Form ◽  
Medium Speed ◽  
Voltage Dependent ◽  
Ratio Dependent ◽  
Space Ratio ◽  
Better Than

A transistor multiplier using the variable area wave form method is described. A bandwidth of 10kc/s and an accuracy better than 1 per cent are obtained using medium-speed switching transistors. A long-tailed pair circuit varies the emitter currents of a symmetrical emitter-coupled multivibrator, which generates a pair of anti-phase rectangular waveforms, with a mark-to-space ratio dependent upon one multiplicand. A voltage dependent upon the other multiplicand is applied to two switches controlled by the waveforms from the multivibrator. The outputs of these switches are combined and smoothed to give the required product.

scholarly journals Effect of sulfur on the scintillation properties of mixed ZnSxSe1–x crystals

2018 ◽  
pp. 36-42
Author(s):  
O. G. Trubaieva ◽  
M. A. Chaika ◽  
O. V. Zelenskaya ◽  
A. I. Lalayants ◽  
S. N. Galkin
Keyword(s):  
Directional Solidification ◽  
Sulfur Content ◽  
Light Output ◽  
Luminescent Properties ◽  
High Energy ◽  
Luminescence Spectra ◽  
Bulk Crystals ◽  
X Ray ◽  
Basic Properties ◽  
Better Than

ZnSxSe1–x based luminescent materials are promising for use as X-ray and g-ray detectors. The main advantage of ZnSxSe1–x crystals is the possibility of making of solid solutions over an entire X-range. It was found that varying the composition of ZnSxSe1–x crystals can change their luminescent properties. Many studies were focused on obtaining ZnSxSe1–x mixed crystals, most using a vapour phase growth methods, and only some of works used the directional solidification. The directional solidification techniques allow growing large ZnSxSe1–x crystals for high-energy particles detectors. Practical use, however, requires the knowledge about luminescent properties of ZnSxSe1–x bulk crystals. This study reports the effect of sulfur content on basic properties of ZnSxSe1–xx bulk crystals grown by Bridgman-Stockbarger method. Six different compounds were studied: ZnS0.07Se0.93, ZnS0.15Se0.85, ZnS0.22Se0.78, ZnS0.28Se0.72, ZnS0.32Se0.68, ZnS0.39Se0.61. The ZnSe(Al) and ZnSe(Te) crystals grown at the similar conditions were used as reference. X-ray luminescence was studied using РЕИС-И (REIS-I) X-ray source (Cu, U = 10—45 kV). КСВУ-23 (KSVU-23) spectrophotometer was used to analyse the emission spectra. The afterglow level h(%) was determined by Smiths Heimann AMS-1 spectrophotometer at excitation by such X-ray and g-ray sources as 123Cs and 241Am (59.5 keV). Light output is one of the main characteristics of the scintillator, which determines its quality as a detector. The ZnSxSe1-x crystals demonstrated increase in the intensity of X-ray induced luminescence spectra with increasing of sulfur content and reached maximum for ZnS0.22Se0.78 composition. Light output of ZnSxSe1–x bulk crystals are higher than those of ZnSe(Te) and ZnSe(Al) commercial crystals. Moreover, thermal stability of scintillation light output of ZnSxSe1–x bulk crystals are also better than those. This investigation has revealed that basic properties of ZnSxSe1–x based scintillation detectors are better than those of ZnSe(Te) and ZnSe(Al).

scholarly journals COVID-19 testing in India in comparison to the rest of the world. If Indian testing strategy was replicated in the other top 15 COVID-19 affected countries in the world, the status would be startlingly different

2020 ◽  
Vol 72 ◽  
pp. 107-109
Author(s):  
Purvish M. Parikh ◽  
Ajay Bapna ◽  
M. Vamshi Krishna ◽  
Prashant Mehta ◽  
Shyam Aggarwal ◽  
...  
Keyword(s):  
Absolute Number ◽  
The Other ◽  
Testing Strategy ◽  
Western Countries ◽  
The World ◽  
The Status ◽  
The Usa ◽  
Entire World ◽  
Positive Results ◽  
Better Than

In terms of the absolute number of COVID-19 positive cases, India is among the top four countries in the world. There is a lot of unwarranted criticism about the alleged inadequacy of COVID-19 testing in India. The facts available from international and publicly available online non-government source covering the entire world show otherwise. While India is fourth in terms of an absolute number of cases, its rank is 132nd in terms of cases per million population and 107th for deaths per million population. These are indications that India is doing much better in the battle against COVID-19 than it is getting credit for. The correct benchmark for the adequacy of testing is the percentage of COVID-19 positive results as compared to the total number of tests performed. India ranks 5th (out of 215) in this respect – being better than some western countries such as the USA, Spain, and France. Thus, the Indian strategy for COVID-19 testing is better and more appropriate than the majority of other countries with the large absolute number of positive cases.

Power Networks Coordinated Planning Based on Improved Steiner Minimum Spanning Tree Theory

2012 ◽  
Vol 433-440 ◽  
pp. 1903-1909
Author(s):  
Han Lin Liu ◽  
Jin Liang Jiang ◽  
Yong Jun Zhang
Keyword(s):  
Spanning Tree ◽  
Minimum Spanning Tree ◽  
Distribution Network ◽  
Weight Coefficient ◽  
Power Networks ◽  
Basic Properties ◽  
Definition Of ◽  
Load Weight ◽  
Better Than

110kV substation’s location and supply area is the crux of the coordination planning for main and distribution network. In this paper, an approach to the coordinated planning of the main grid and distribution network is proposed, which is based on improved weighted Steiner minimum spanning tree theory. This paper will analysis the basic properties of substation firstly, make the definition of Load Weight Coefficient, then use a bound circle to delineate the optimization area. At last, make Load Weight Coefficient as weight, use improved weighted Steiner minimum spanning tree theory to determine the final location of substation. Actual examples show that, in favor of coordinated planning, this method result is obviously better than traditional model’s.

Induced Alpha-band Oscillations Reflect Ratio-dependent Number Discrimination in the Infant Brain

2009 ◽  
Vol 21 (12) ◽  
pp. 2398-2406 ◽  
Author(s):  
Melissa E. Libertus ◽  
Laura B. Pruitt ◽  
Marty G. Woldorff ◽  
Elizabeth M. Brannon
Keyword(s):  
Spectral Power ◽  
Brain Activity ◽  
Human Life ◽  
Alpha Band ◽  
Weber’S Law ◽  
Weber's Law ◽  
Ratio Dependence ◽  
Number Discrimination ◽  
Behavioral Studies ◽  
Ratio Dependent

Behavioral studies show that infants are capable of discriminating the number of objects or events in their environment, while also suggesting that number discrimination in infancy may be ratio-dependent. However, due to limitations of the dependent measures used with infant behavioral studies, the evidence for ratio dependence falls short of the vast psychophysical datasets that have established ratio dependence, and thus, adherence to Weber's Law in adults and nonhuman animals. We addressed this issue in two experiments that presented 7-month-old infants with familiar and novel numerosities while electroencephalogram measures of their brain activity were recorded. These data provide convergent evidence that the brains of 7-month-old infants detected numerical novelty. Alpha-band and theta-band oscillations both differed for novel and familiar numerical values. Most importantly, spectral power in the alpha band over midline and right posterior scalp sites was modulated by the ratio between the familiar and novel numerosities. Our findings provide neural evidence that numerical discrimination in infancy is ratio dependent and follows Weber's Law, thus indicating continuity of these cognitive processes over development. Results are also consistent with the idea that networks in the frontal and parietal cortices support ratio-dependent number discrimination in the first year of human life, consistent with what has been reported in neuroimaging studies in adults and older children.

scholarly journals Infants Show Ratio-dependent Number Discrimination Regardless of Set Size

Infancy ◽  
2013 ◽  
Vol 18 (6) ◽  
pp. 927-941 ◽  
Author(s):  
Ariel Starr ◽  
Melissa E. Libertus ◽  
Elizabeth M. Brannon
Keyword(s):  
Set Size ◽  
Number Discrimination ◽  
Ratio Dependent

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

Localization of immunolabels by electron microscopy and image averaging

1983 ◽  
Vol 41 ◽  
pp. 282-283
Author(s):  
J. Frank ◽  
P.-Y. Sizaret ◽  
A. Verschoor ◽  
J. Lamy
Keyword(s):  
Electron Microscopy ◽  
Single Particle ◽  
Attachment Site ◽  
Uranyl Acetate ◽  
Limulus Polyphemus ◽  
Resolution Limit ◽  
Electron Microscopic ◽  
Image Averaging ◽  
Top View ◽  
Better Than

The accuracy with which the attachment site of immunolabels bound to macromolecules may be localized in electron microscopic images can be considerably improved by using single particle averaging. The example studied in this work showed that the accuracy may be better than the resolution limit imposed by negative staining (∽2nm).The structure used for this demonstration was a halfmolecule of Limulus polyphemus (LP) hemocyanin, consisting of 24 subunits grouped into four hexamers. The top view of this structure was previously studied by image averaging and correspondence analysis. It was found to vary according to the flip or flop position of the molecule, and to the stain imbalance between diagonally opposed hexamers (“rocking effect”). These findings have recently been incorporated into a model of the full 8 × 6 molecule.LP hemocyanin contains eight different polypeptides, and antibodies specific for one, LP II, were used. Uranyl acetate was used as stain. A total of 58 molecule images (29 unlabelled, 29 labelled with antl-LPII Fab) showing the top view were digitized in the microdensitometer with a sampling distance of 50μ corresponding to 6.25nm.

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