scholarly journals Early Specialization and Critical Periods in Acquiring Expertise: A Comparison of Traditional Versus Detection Talent Identification in Team GB Cycling at London 2012

2021 ◽  
pp. 1-17
Author(s):  
Toby Staff ◽  
Fernand Gobet ◽  
Andrew Parton
Keyword(s):  
Critical Period ◽  
Genetic Basis ◽  
Development Program ◽  
Critical Periods ◽  
Talent Identification ◽  
London 2012 ◽  
Early Specialization

The aim of this study was to compare two methodologies employed by the British Cycling talent identification program. Specifically, the authors investigated cyclists selected to represent GB cycling team at the London 2012 Olympics using (a) a traditional talent identification methodology (British Cycling Olympic Development Program), where selection is based upon race results and (b) a detection talent identification methodology (U.K. Sport Talent Team Program), which is a multi-Olympic event initiative that identifies athletic potential from physical and skill-based tests. To facilitate this comparison, the authors calculated the speed with which expertise was acquired. A Mann–Whitney U test (U = 16.0, p = .031) indicated that the speed of acquiring expertise was quicker in detection talent identification (Mdn = 5.4) than traditional talent identification (Mdn = 7.2). Practice started later with detection talent identification than with traditional talent identification (14.12 years vs. 11.23 years, respectively), which affected the period to excellence. Thus, detection talent identification resulted in an absence of early specialization, which suggests a critical period for attaining cycling expertise. The authors hypothesize a genetic basis of talent and propose that critical periods are important in detection talent identification programs.

scholarly journals Demand Response Coupled with Dynamic Thermal Rating for Increased Transformer Reserve and Lifetime

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1378
Author(s):  
Ildar Daminov ◽  
Rémy Rigo-Mariani ◽  
Raphael Caire ◽  
Anton Prokhorov ◽  
Marie-Cécile Alvarez-Hérault
Keyword(s):  
Ambient Temperature ◽  
Demand Response ◽  
Thermal Model ◽  
Critical Period ◽  
Optimization Problem ◽  
Integrated Management ◽  
Critical Periods ◽  
Network Access ◽  
Maximal Amplitude ◽  
Demand Response Program

(1) Background: This paper proposes a strategy coupling Demand Response Program with Dynamic Thermal Rating to ensure a transformer reserve for the load connection. This solution is an alternative to expensive grid reinforcements. (2) Methods: The proposed methodology firstly considers the N-1 mode under strict assumptions on load and ambient temperature and then identifies critical periods of the year when transformer constraints are violated. For each critical period, the integrated management/sizing problem is solved in YALMIP to find the minimal Demand Response needed to ensure a load connection. However, due to the nonlinear thermal model of transformers, the optimization problem becomes intractable at long periods. To overcome this problem, a validated piece-wise linearization is applied here. (3) Results: It is possible to increase reserve margins significantly compared to conventional approaches. These high reserve margins could be achieved for relatively small Demand Response volumes. For instance, a reserve margin of 75% (of transformer nominal rating) can be ensured if only 1% of the annual energy is curtailed. Moreover, the maximal amplitude of Demand Response (in kW) should be activated only 2–3 h during a year. (4) Conclusions: Improvements for combining Demand Response with Dynamic Thermal Rating are suggested. Results could be used to develop consumer connection agreements with variable network access.

Critical periods for functional and anatomical compensation in lateral suprasylvian visual area following removal of visual cortex in cats

1984 ◽  
Vol 52 (5) ◽  
pp. 941-960 ◽  
Author(s):  
L. Tong ◽  
R. E. Kalil ◽  
P. D. Spear
Keyword(s):  
Visual Cortex ◽  
Critical Period ◽  
Ocular Dominance ◽  
Direction Selectivity ◽  
Visual Area ◽  
Critical Periods ◽  
Cortex Lesion ◽  
Thalamic Projections ◽  
Adult Cats ◽  
Visual Cortical

Previous experiments have found that neurons in the cat's lateral suprasylvian (LS) visual area of cortex show functional compensation following removal of visual cortical areas 17, 18, and 19 on the day of birth. Correspondingly, an enhanced retino-thalamic pathway to LS cortex develops in these cats. The present experiments investigated the critical periods for these changes. Unilateral lesions of areas 17, 18, and 19 were made in cats ranging in age from 1 day postnatal to 26 wk. When the cats were adult, single-cell recordings were made from LS cortex ipsilateral to the lesion. In addition, transneuronal autoradiographic methods were used to trace the retino-thalamic projections to LS cortex in many of the same animals. Following lesions in 18- and 26-wk-old cats, there is a marked reduction in direction-selective LS cortex cells and an increase in cells that respond best to stationary flashing stimuli. These results are similar to those following visual cortex lesions in adult cats. In contrast, the percentages of cells with these properties are normal following lesions made from 1 day to 12 wk of age. Thus the critical period for development of direction selectivity and greater responses to moving than to stationary flashing stimuli in LS cortex following a visual cortex lesion ends between 12 and 18 wk of age. Following lesions in 26-wk-old cats, there is a decrease in the percentage of cells that respond to the ipsilateral eye, which is similar to results following visual cortex lesions in adult cats. However, ocular dominance is normal following lesions made from 1 day to 18 wk of age. Thus the critical period for development of responses to the ipsilateral eye following a lesion ends between 18 and 26 wk of age. Following visual cortex lesions in 2-, 4-, or 8-wk-old cats, about 30% of the LS cortex cells display orientation selectivity to elongated slits of light. In contrast, few or no cells display this property in normal adult cats, cats with lesions made on the day of birth, or cats with lesions made at 12 wk of age or later. Thus an anomalous property develops for many LS cells, and the critical period for this property begins later (between 1 day and 2 wk) and ends earlier (between 8 and 12 wk) than those for other properties.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals The ex-illiterate brain: The critical period, cognitive reserve and HAROLD model

2009 ◽  
Vol 3 (3) ◽  
pp. 222-227 ◽  
Author(s):  
Maria Vania Silva Nunes ◽  
Alexandre Castro-Caldas ◽  
Dolores Del Rio ◽  
Fernado Maestú ◽  
Tomás Ortiz
Keyword(s):  
Recognition Test ◽  
Cognitive Skills ◽  
Critical Period ◽  
Cognitive Reserve ◽  
Brain Activity ◽  
High Educational Level ◽  
Critical Periods ◽  
Language Recognition ◽  
Regular Time ◽  
The Brain

Abstract The lifelong acquisition of cognitive skills shapes the biology of the brain. However, there are critical periods for the best use of the brain to process the acquired information. Objectives: To discuss the critical period of cognitive acquisition, the concept of cognitive reserve and the HAROLD (Hemispheric Asymmetry Reduction in Older adults) model. Methods: Seven women who learned how to read and to write after the age of 50 (ex-illiterates) and five women with 10 years of regular schooling (controls) were submitted to a language recognition test while brain activity was being recorded using magnetoencephalography. Spoken words were delivered binaurally via two plastic tubs terminating in ear inserts, and recordings were made with a whole head magnetometer consisting of 148 magnetometer coils. Results: Both groups performed similarly on the task of identifying target words. Analysis of the number of sources of activity in the left and right hemispheres revealed significant differences between the two groups, showing that ex-illiterate subjects exhibited less brain functional asymmetry during the language task. Conclusions: These results should be interpreted with caution because the groups were small. However, these findings reinforce the concept that poorly educated subjects tend to use the brain for information processing in a different way to subjects with a high educational level or who were schooled at the regular time. Finally, the recruiting of both hemispheres to tackle the language recognition test occurred to a greater degree in the ex-illiterate group where this can be interpreted as a sign of difficulty performing the task.

scholarly journals Critical periods in amblyopia

2018 ◽  
Vol 35 ◽  
Author(s):  
TAKAO K. HENSCH ◽  
ELIZABETH M. QUINLAN
Keyword(s):  
Visual Cortex ◽  
Critical Period ◽  
Molecular Mechanisms ◽  
Ocular Dominance ◽  
Molecular Genetic ◽  
Monocular Deprivation ◽  
Critical Periods ◽  
Developmental Constraints ◽  
Early Postnatal Development ◽  
Visual Cortical

AbstractThe shift in ocular dominance (OD) of binocular neurons induced by monocular deprivation is the canonical model of synaptic plasticity confined to a postnatal critical period. Developmental constraints on this plasticity not only lend stability to the mature visual cortical circuitry but also impede the ability to recover from amblyopia beyond an early window. Advances with mouse models utilizing the power of molecular, genetic, and imaging tools are beginning to unravel the circuit, cellular, and molecular mechanisms controlling the onset and closure of the critical periods of plasticity in the primary visual cortex (V1). Emerging evidence suggests that mechanisms enabling plasticity in juveniles are not simply lost with age but rather that plasticity is actively constrained by the developmental up-regulation of molecular ‘brakes’. Lifting these brakes enhances plasticity in the adult visual cortex, and can be harnessed to promote recovery from amblyopia. The reactivation of plasticity by experimental manipulations has revised the idea that robust OD plasticity is limited to early postnatal development. Here, we discuss recent insights into the neurobiology of the initiation and termination of critical periods and how our increasingly mechanistic understanding of these processes can be leveraged toward improved clinical treatment of adult amblyopia.

Critical Period of Quackgrass (Elytrigia repens) Removal in Potatoes (Solanum tuberosum)

Weed Science ◽  
1994 ◽  
Vol 42 (4) ◽  
pp. 528-533 ◽  
Author(s):  
R. Baziramakenga ◽  
Gilles D. Leroux
Keyword(s):  
Critical Period ◽  
Yield Loss ◽  
Field Trials ◽  
Quebec City ◽  
Critical Periods ◽  
Marketable Yield ◽  
Elytrigia Repens ◽  
Medium Level ◽  
High Level ◽  
Loss Level

Field trials were carried out in 1989 and 1990 at St-Augustin, near Québec City, Canada, to determine the critical periods of quackgrass control in potato submitted to three levels of infestation. Potato yield losses due to quackgrass interference increased with quackgrass infestation and length of duration of interference. Quackgrass interference influenced marketable tuber yields more than total tuber yields. Duration of the critical period varied depending on the level of quackgrass infestation and year. Based on an arbitrary 5% level of marketable yield loss, the critical period started at ca. 15 days after emergence (DAE) of potato at low level of infestation, and at ca. 3 DAE at medium level of infestation. At high level of infestation, the critical period began prior to the emergence of potato. The end of the critical period of quackgrass removal was extremely variable across quackgrass infestation level and year and ranged from 23 to 68 DAE of potato at a 5 % yield loss level. It appears that onset of interference varied less than the end of it, indicating that early quackgrass control is necessary to prevent yield loss.

Pharmacological Manipulation of Critical Period Plasticity

2018 ◽  
Author(s):  
Ramon Guirado ◽  
Eero Castrén
Keyword(s):  
Critical Period ◽  
Adult Brain ◽  
Brain Disorders ◽  
Critical Periods ◽  
Pharmacological Treatments ◽  
New Paradigm ◽  
Early Postnatal Development ◽  
Pharmacological Manipulation ◽  
Efficient Recovery ◽  
Activity Dependent

Neuronal networks are refined through an activity-dependent competition during critical periods of early postnatal development. Recent studies have shown that critical period plasticity is influenced by a number of environmental factors, including drugs that are widely used for the treatment of brain disorders. These findings suggest a new paradigm, where pharmacological treatments can be used to open critical period–like plasticity in the adult brain. The plastic networks can then be modified through rehabilitation or psychotherapy to rewire those abnormally wired during development. This kind of combination of pharmacotherapy with physical or psychological rehabilitation may open a new opportunity for a more efficient recovery of a number of neurological and neuropsychiatric disorders.

A Higher-Order Period Function and Its Application

2015 ◽  
Vol 25 (10) ◽  
pp. 1550140 ◽  
Author(s):  
Linping Peng ◽  
Lianghaolong Lu ◽  
Zhaosheng Feng
Keyword(s):  
Periodic Orbits ◽  
Upper Bound ◽  
Critical Period ◽  
Higher Order ◽  
Quadratic System ◽  
Critical Periods ◽  
Explicit Formulas ◽  
Period Function ◽  
Isochronous System ◽  
Isochronous Centers

This paper derives explicit formulas of the q th period bifurcation function for any perturbed isochronous system with a center, which improve and generalize the corresponding results in the literature. Based on these formulas to the perturbed quadratic and quintic rigidly isochronous centers, we prove that under any small homogeneous perturbations, for ε in any order, at most one critical period bifurcates from the periodic orbits of the unperturbed quadratic system. For ε in order of 1, 2, 3, 4 and 5, at most three critical periods bifurcate from the periodic orbits of the unperturbed quintic system. Moreover, in each case, the upper bound is sharp. Finally, a family of perturbed quintic rigidly isochronous centers is shown, which has three, for ε in any order, as the exact upper bound of the number of critical periods.

scholarly journals Understanding individual variation in levels of second language attainment through the lens of critical period mechanisms

2018 ◽  
Vol 21 (5) ◽  
pp. 930-931 ◽  
Author(s):  
REBECCA REH ◽  
MARIA ARREDONDO ◽  
JANET F. WERKER
Keyword(s):  
Second Language ◽  
Category Learning ◽  
Critical Period ◽  
First Language ◽  
Visual Language ◽  
Phonetic Category ◽  
Critical Periods ◽  
L2 Acquisition ◽  
Language Discrimination ◽  
L1 Acquisition

Mayberry and Kluender (2017) present an important and compelling argument that in order to understand critical periods (CPs) in language acquisition, it is essential to disentangle studies of late first language (L1) acquisition from those of second language (L2) acquisition. Their primary thesis is that timely exposure to an L1 is crucial for establishing language circuitry, thus providing a foundation on which an L2 can build. They note that while there is considerable evidence of interference from the L1 on acquisition of the L2 – especially in late L2 learners (as in our work on cascading influences on phonetic category learning and visual language discrimination, e.g., Werker & Hensch, 2015 and Weikum, Vouloumanos, Navarra, Soto-Faraco, Sebastián-Gallés & Werker, 2013, respectively) – there are other examples of ways in which the L1 can scaffold L2 acquisition. Mayberry and Kluender take this evidence of L1 scaffolding L2 as undermining the value of considering CPs as useful in understanding L2 acquisition.

The Concept and Application of Early Economic Period Threshold: The Case of DCPA in Onions (Allium Cepa)

Weed Science ◽  
1995 ◽  
Vol 43 (4) ◽  
pp. 634-639 ◽  
Author(s):  
Claudio M. Dunan ◽  
Philip Westra ◽  
Edward E. Schweizer ◽  
Donald W. Lybecker ◽  
Frank D. Moore
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Crop Yields ◽  
Economic Feasibility ◽  
Control Measures ◽  
Economic Losses ◽  
Weed Competition ◽  
Critical Periods ◽  
Control Efficacy ◽  
The Impact

The question of when to control weeds traditionally has been approached with the calculation of critical periods (CP) based on crop yields. The concept of economic critical period (ECP) and early (EEPT) and late (LEFT) economic period thresholds are presented as a comprehensive approach to answer the same question based on economic losses and costs of control. ECP is defined as the period when the benefit of controlling weeds is greater than its cost. EEPT and LEFT are the limits of the ECP and can be used to determine when first and last weed control measures should be performed. Calculation of EEPT accounts for the economic losses due to weed competition that occur between planting and postemergence weed control. In this way it is possible to better evaluate the economic feasibility of using preplant or preemergence control tactics. The EEPT for DCPA application is analyzed in the context of onion production in Colorado. The EEPT for DCPA application was calculated from an empirical regression model that assessed the impact of weed load and time of weed removal on onion yields. The EEPT was affected by control efficacy, weed-free yield, DCPA cost, and onion price. DCPA application was economically advisable in only one of 20 fields analyzed because of the tow DCPA efficacy (60%).

scholarly journals Dynamics of morphometric parameters of α-endocrinocytes of mammal pancreas

2020 ◽  
Vol 175 ◽  
pp. 03023
Author(s):  
Olga Dilekova ◽  
Cristina Pavlova ◽  
Valentina Shpygova ◽  
Nikolai Agarkov ◽  
Vladislav Porublyov
Keyword(s):  
Postnatal Development ◽  
Critical Period ◽  
Domestic Animals ◽  
Morphometric Parameters ◽  
The Body ◽  
Postnatal Ontogenesis ◽  
Dynamic Processes ◽  
Physiological Changes ◽  
Critical Periods ◽  
Age Related

In domestic animals in postnatal ontogenesis, statistically significant changes in the number of α-endocrinocytes and the values of their nuclear-cytoplasmic ratio in the endocrine islets of pancreas have been revealed, which reflects the species and age-related dynamic processes of its morphofunctional development in animals. In cattle and small cattle (sheep), pigs, dogs and cats, two critical periods of postnatal development of the pancreas have been identified. The first critical period is observed from the birth to the age of three months. It is associated with an alimentary factor: the transition from a dairy diet to roughage, which leads to a decrease in the values of morphometric indicators of the pancreas and the restructuring of the functional work of the organ as a whole. The second critical period is registered in animals during puberty, that is, at 6 months of age, which is associated with the release of hormonal inducers aimed primarily at the implementation of physiological changes in the body.

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