scholarly journals A lateralised design for the interaction of visual memories and heading representations in navigating ants

2020 ◽  
Author(s):  
Antoine Wystrach ◽  
Florent Le Moël ◽  
Leo Clement ◽  
Sebastian Schwarz
Keyword(s):  
Brain Area ◽  
Computational Modelling ◽  
Motor Command ◽  
Central Complex ◽  
Stage Process ◽  
Celestial Compass ◽  
Left And Right ◽  
Behavioural Experiments ◽  
New Perspective

AbstractThe navigational skills of ants, bees and wasps represent one of the most baffling examples of the powers of minuscule brains. Insects store long-term memories of the visual scenes they experience 1, and they use compass cues to build a robust representation of directions 2,3. We know reasonably well how long-term memories are formed, in a brain area called the Mushroom Bodies (MB) 4–8, as well as how heading representations are formed in another brain area called the Central Complex (CX) 9–12. However, how such memories and heading representations interact to produce powerful navigational behaviours remains unclear 7,13,14. Here we combine behavioural experiments with computational modelling that is strictly based on connectomic data to provide a new perspective on how navigation might be orchestrated in these insects. Our results reveal a lateralised design, where signals about whether to turn left or right are segregated in the left and right hemispheres, respectively. Furthermore, we show that guidance is a two-stage process: the recognition of visual memories – presumably in the MBs – does not directly drive the motor command, but instead updates a “desired heading” – presumably in the CX – which in turn is used to control guidance using celestial compass information. Overall, this circuit enables ants to recognise views independently of their body orientation, and combines terrestrial and celestial cues in a way that produces exceptionally robust navigation.

scholarly journals Current and New Approaches to Predict the Deflections of One-Way Flexural Members with a Focus on Composite Steel Deck Slabs Voided by Circular Tubes

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 421
Author(s):  
Chang-Hwan Lee ◽  
Iman Mansouri ◽  
Jaehoon Bae ◽  
Jaeho Ryu
Keyword(s):  
Structural Function ◽  
Flexural Members ◽  
Long Span ◽  
Deck Slabs ◽  
New Type ◽  
New Perspective ◽  
Flexural Tests ◽  
Prediction Approach ◽  
Steel Deck

A new type of composite voided slab, the TUBEDECK (TD), which utilizes the structural function of profiled steel decks, has recently been proposed. Previous studies have confirmed that the flexural strength of TD slabs can be calculated based on the full composite contribution of the steel deck, but for long-span flexural members, the deflection serviceability requirement is often dominant. Herein, we derived a novel deflection prediction approach using the results of flexural tests on slab specimens, focusing on TD slabs. First, deflection prediction based on modifications of the current code was proposed. Results revealed that TD slabs exhibited smaller long-term deflections and at least 10% longer maximum span lengths than solid slabs, indicating their greater efficiency. Second, a novel rational method was derived for predicting deflections without computing the effective moment of inertia. The ultimate deflections predicted by the proposed method correlated closely with the deflection under maximum bending moments. To calculate immediate deflections, variation functions for the concrete strain at the extreme compression fiber and neutral axis depth were assumed with predictions in good agreement with experiments. The proposed procedure has important implications in highlighting a new perspective on the deflection prediction of reinforced concrete and composite flexural members.

Antioestrogen inhibition of oestradiol-induced alterations in hypothalamic noradrenaline turnover

1985 ◽  
Vol 106 (1) ◽  
pp. 37-42 ◽  
Author(s):  
C. Hiemke ◽  
B. Poetz ◽  
R. Ghraf
Keyword(s):  
Brain Area ◽  
Serum Levels ◽  
Ovariectomized Rats ◽  
Noradrenaline Turnover ◽  
Stimulatory Action ◽  
Enhanced Sensitivity ◽  
Oestradiol Benzoate ◽  
Lh Release ◽  
Secretory System

ABSTRACT Long-term (4–6 weeks) ovariectomized rats were injected with either oestradiol benzoate (OB; 20 μg s.c.) or monohydroxytamoxifen (MTAM; 0·2 mg i.p.) plus OB. Oestradiol benzoate was administered at 12.00 h on day 0 and MTAM was given immediately before OB, followed by further injections twice daily to maintain sufficiently high antioestrogen levels. When given alone, OB reduced the serum levels of LH during the morning (08.00–09.00 h) and afternoon (17.30–18.30 h) hours of day 3 after priming. The feedback actions of OB on LH release were accompanied by time-dependent alterations of noradrenaline turnover in the preoptic–anterior hypothalamic brain area (POAH). On day 3 after priming the noradrenaline turnover rate was reduced in the morning and increased in the afternoon. The increase correlated with an enhanced sensitivity of the LH secretory system to progesterone. The antioestrogen MTAM blocked the OB-induced sensitization of LH release to the stimulatory action of progesterone and interfered with the stimulatory long-term effect of oestradiol on hypothalamic noradrenaline turnover. The data strongly support the view that the oestrogen-induced afternoon increase of noradrenaline turnover in the POAH represents a pre-requisite for the induction of LH surges. The stimulatory effect of oestradiol on hypothalamic noradrenaline turnover seems to be mediated by a classical oestrogen receptor mechanism. J. Endocr. (1985) 106, 37–42

scholarly journals CICT: New Eyes on Computational Competence in Computational Science

2018 ◽  
Vol 16 ◽  
pp. 01007
Author(s):  
Rodolfo A. Fiorini
Keyword(s):  
Modeling And Simulation ◽  
Formal Language ◽  
Traditional Approach ◽  
System Modeling ◽  
Computational Modelling ◽  
Computational Science ◽  
Open Logic ◽  
Information Conservation ◽  
Biomedical System ◽  
New Perspective

Science does not exists to enlighten people's minds only. It mainly exists to show the educated way from quanta to qualia. And that way starts from computational competence. In previous papers published elsewhere, we have already shown that traditional Q Arithmetic can be regarded as a highly sophisticated open logic, powerful and flexible bidirectional formal language of languages, according to "Computational Information Conservation Theory" (CICT) new perspective. This new awareness can offer competitive approach to guide more effective and convenient algorithm development and application to arbitrary multiscale (AMS) biomedical system modeling and simulation. An articulated example on function computational modelling is presented and compared to standard, well-known and traditional approach. Results are critically discussed.

Neuroprotective properties of mitochondria-targeted antioxidants of the SkQ-type

2016 ◽  
Vol 27 (8) ◽  
pp. 849-855 ◽  
Author(s):  
Nickolay K. Isaev ◽  
Elena V. Stelmashook ◽  
Elisaveta E. Genrikhs ◽  
Galina A. Korshunova ◽  
Natalya V. Sumbatyan ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Brain Area ◽  
Hippocampal Slices ◽  
Amyloid Β ◽  
Long Term Potentiation ◽  
Term Potentiation ◽  
Neuroprotective Action

AbstractIn 2008, using a model of compression brain ischemia, we presented the first evidence that mitochondria-targeted antioxidants of the SkQ family, i.e. SkQR1 [10-(6′-plastoquinonyl)decylrhodamine], have a neuroprotective action. It was shown that intraperitoneal injections of SkQR1 (0.5–1 μmol/kg) 1 day before ischemia significantly decreased the damaged brain area. Later, we studied in more detail the anti-ischemic action of this antioxidant in a model of experimental focal ischemia provoked by unilateral intravascular occlusion of the middle cerebral artery. The neuroprotective action of SkQ family compounds (SkQR1, SkQ1, SkQTR1, SkQT1) was manifested through the decrease in trauma-induced neurological deficit in animals and prevention of amyloid-β-induced impairment of long-term potentiation in rat hippocampal slices. At present, most neurophysiologists suppose that long-term potentiation underlies cellular mechanisms of memory and learning. They consider inhibition of this process by amyloid-β1-42as anin vitromodel of memory disturbance in Alzheimer’s disease. Further development of the above studies revealed that mitochondria-targeted antioxidants could retard accumulation of hyperphosphorylated τ-protein, as well as amyloid-β1-42, and its precursor APP in the brain, which are involved in developing neurodegenerative processes in Alzheimer’s disease.

scholarly journals 7 Mixing aggression and floor type during gestation have implications for sow reproductive performance

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 4-5
Author(s):  
Martyna E Lagoda ◽  
Laura A Boyle ◽  
Joanna Marchewka ◽  
Julia A Calderón Díaz
Keyword(s):  
Skin Lesion ◽  
Aggressive Behavior ◽  
Reproductive Performance ◽  
Cycle Length ◽  
Dominance Hierarchy ◽  
Body Regions ◽  
Left And Right ◽  
Piglet Mortality ◽  
Carry Over

Abstract Aggressive behavior resulting from mixing to establish a dominance hierarchy is a welfare concern for group-housed sows. The associated stress could negatively impact reproductive performance (RP). Objectives of this study were to investigate associations between 1) mixing aggression intensity and RP within and between parities one (P1) and two (P2), and 2) aggression intensity, floor type and RP. A total of 164 gilts were followed through two parities. Gilts were mixed into stable groups of eight unfamiliar individuals four days after insemination, and housed on fully-slatted floors, either uncovered (CON; n = 84) or covered (RUB; n = 80) by a rubber slat-mat until farrowing (for both parities). Skin lesion scores (SLS) (proxy for mixing aggression intensity), were recorded 24–72 hrs post-mixing (0 = no lesions to 5 = severe lesions) on five body regions on left and right sides, and on the tail, in both parities. Total SLS was calculated for each sow. RP data were retrospectively acquired from farm records for both parities. Data were analyzed using GLMM in PROC GLIMMIX of SAS (v9.4) where 1) each parity analyzed separately, and 2) SLS in P1 used to predict RP in P2. Gilts with higher SLS in P2 had higher piglet mortality (P = 0.021) and longer cycle length (P = 0.003) in P2. Gilts with higher SLS in P1 had more non-productive days (P < 0.001) in P2. CON gilts had higher SLS than RUB gilts (P = 0.017) in P1, but not in P2 (P > 0.05). CON gilts also had more piglets born dead (P = 0.004) and tended to crush more piglets (P = 0.097) in P2. Our results confirm that mixing aggression impacts RP in the current parity negatively. They also suggest that mixing aggression experienced by gilts may have long-term negative carry-over effects on performance in subsequent parities. Use of rubber flooring appears to mitigate detrimental effects of mixing aggression, perhaps through improved sow comfort.

scholarly journals Hierarchy in language interpretation: evidence from behavioural experiments and computational modelling

2021 ◽  
pp. 1-20
Author(s):  
Cas W. Coopmans ◽  
Helen de Hoop ◽  
Karthikeya Kaushik ◽  
Peter Hagoort ◽  
Andrea E. Martin
Keyword(s):  
Computational Modelling ◽  
Language Interpretation ◽  
Behavioural Experiments

Movers and Stayers

2021 ◽  
Author(s):  
Irwin L. Morris
Keyword(s):  
Progressive Era ◽  
Republican Party ◽  
Democratic Party ◽  
Southern Politics ◽  
Political Landscape ◽  
Migratory Patterns ◽  
New Perspective ◽  
The Right ◽  
Democratic Support

Democrats once dominated the “Solid South.” By the turn of the 21st century, Republicans had taken control. We are in the midst of the dawning of new, more progressive era. Theories explaining Republican growth provide little guidance, but a new perspective—Movers and Stayers theory—explains this recent growth in Democratic support and the ways in which population growth has produced it. Migratory patterns play a significant role in southern politics. Young, well-educated in-migrants fostered Republican growth in the last century. Today, these increasingly progressive young, well-educated movers are growing the Democratic Party. Movers bring their politics to their new communities. Their progressivism fosters the same among long-term residents (stayers) in their new communities. But the declining communities they left show the effects of their exit. In our racialized partisan environment, white stayers respond to the threat of declining communities by shifting to the right and identifying with the Republican Party. Conversely, African Americans respond to community threat by maintaining their progressivism. Few Latinos live in declining communities; Latino stayers in fast growing communities become more Democratic. While movers of retirement age are more conservative than younger movers, they are more liberal than those who retire in place—not quite the demographic windfall Republicans in aging areas have hoped for. These dynamics are altering the southern political landscape, and differences between growing areas and declining areas are accelerating. Absent a wholesale reinvention of southern politics along the lines of class or (possibly) age, the current partisan trajectory does not bode well for Republicans. The COVID-19 pandemic will not change that.

Autonomous Ocean Turbulence Measurements From a Moored Upwardly Rising Profiler Based on a Buoyancy-Driven Mechanism

2017 ◽  
Vol 51 (4) ◽  
pp. 12-22 ◽  
Author(s):  
Xiuyan Liu ◽  
Xin Luan ◽  
Z. Daniel Deng ◽  
Dalei Song ◽  
Shengbo Zang ◽  
...  
Keyword(s):  
The Novel ◽  
Ocean Turbulence ◽  
Turbulence Measurements ◽  
Sea Trial ◽  
Dissipation Rates ◽  
Turbulence Mixing ◽  
Mooring Cable ◽  
High Vertical Resolution ◽  
New Perspective

AbstractAn autonomous Moored Reciprocating Vertical Profiler (MRVP) has been developed and tested for measuring ocean turbulence. The MRVP is designed to combine the advantages of long-term moored measurements at specified depths with those of short-term ship-supported continuous profiling performed at high vertical resolution. The profiler is programmed to repeat vertical motions autonomously along the mooring cable based on a buoyancy-driven mechanism. A sea trial has been conducted in the South China Sea to evaluate the performance of the profiler. The shear probe data are unreliable when the flow past sensors is not sufficiently greater than an estimate of turbulent velocity. For 65% of the dataset, turbulence measurements are of high quality and the magnitude of dissipation rates is up to O(10−10) W kg−1. To minimize the contamination induced by instrument vibration and improve the estimation of turbulent kinetic energy terms, an advanced cross-spectrum algorithm is implemented to the measured shear data. The corrected spectra agreed well with the empirical Nasmyth spectrum, and dissipation rates had averagely decreased a factor of 2 and 8 times lower than the raw spectra. The autonomous MRVP is proven to be a stable platform, and the novel upward measurement provides a new perspective for measuring long-term time series of turbulence mixing.

Activator calcium and myocardial contractility in fetal sheep exposed to long-term high-altitude hypoxia

1997 ◽  
Vol 272 (3) ◽  
pp. H1196-H1204 ◽  
Author(s):  
V. A. Browne ◽  
V. M. Stiffel ◽  
W. J. Pearce ◽  
L. D. Longo ◽  
R. D. Gilbert
Keyword(s):  
High Altitude ◽  
Myocardial Contractility ◽  
Active Tension ◽  
Fetal Sheep ◽  
Lower Maximum ◽  
Left And Right ◽  
Baseline Values ◽  
The Right ◽  
Maximum Rate Of Rise

We studied myocardial contractility in fetal sheep from ewes exposed to approximately 112 days of hypoxia at high altitude (3,820 m). We measured the inotropic response to extracellular Ca2+ concentration ([Ca2+]o, 0.2-10 mM) and ryanodine (10(-10) to 10(-4) M) in isometrically contracting papillary muscles and quantified dihydropyridine (DHPR) and ryanodine (RyR) receptors. In hypoxic fetuses, curves describing the force-[Ca2+]o relationship were shifted left, and the top plateaus were decreased by approximately 35% in both left and right ventricles. In normoxic and hypoxic fetuses, ryanodine (10(-4) M) reduced maximum active tension (Tmax) to approximately 25-40% of baseline values, indicating that the sarcoplasmic reticulum was the chief source of activator Ca2+ and that Ca2+ influx alone was not sufficient to activate a contraction of normal amplitude. Hypoxia resulted in a lower Tmax in the right ventricle and a lower maximum rate of rise in the left ventricle after treatment with ryanodine. DHPR number did not change, but RyR number and the RyR/DHPR in both ventricles were higher in hypoxic fetuses. We conclude that hypoxia decreases contractility, possibly by reducing the availability of activator Ca2+. Further studies are needed to directly measure the Ca2+ current and intracellular Ca2+ transient and to examine myofilament protein and adenosinetriphosphatase activity.

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