Contralateral coordination and retargeting of limb movements during scratching in the locust

1998 ◽  
Vol 201 (13) ◽  
pp. 2021-2032 ◽  
Author(s):  
T Matheson

Locusts, Schistocerca gregaria, in common with many limbed vertebrates, can make directed scratching movements in response to tactile stimulation. For instance, stimulation of different sites on a wing elicits different movements that are accurately targeted so that the hindleg tarsus passes across the stimulus site. I have analysed these limb movements to define the ability of a locust to target stimulus sites correctly under a range of experimental conditions. In particular, I describe aspects of the behaviour that reveal possible neuronal pathways underlying the responses. These neuronal pathways will be the subject of further physiological analyses. Limb targeting during scratching is continuously graded in form; different patterns of movement are not separated by sharp transitions. The computation of limb trajectory takes into account the starting posture of the hindleg, so that different trajectories can be used to reach a common stimulus site from different starting postures. Moreover, the trajectories of the two hindlegs moving simultaneously from different starting postures in response to a single stimulus can be different, so that their tarsi converge onto the common stimulus site. Different trajectories can be used to reach a common stimulus site from the same start posture. Targeting information from a forewing is passed not only down the nerve cord to the ipsilateral hindleg but also across the nerve cord, so that the contralateral hindleg can also make directed movements. This contralateral transmission does not rely on peripheral sensory feedback. When the stimulus site moves during a rhythmical scratch, the targeting of subsequent cycles reflects this change. Both ipsilateral and contralateral hindlegs can retarget their movements. The trajectory of a single cycle of scratching directed towards a particular stimulus site can be modified after it has begun, so that the tarsus is redirected towards a new stimulus site.

1997 ◽  
Vol 200 (1) ◽  
pp. 93-100 ◽  
Author(s):  
T Matheson

Intact locusts (Schistocerca gregaria) respond to tactile stimulation of their folded wings with rhythmic scratching movements of the ipsilateral hindleg that are directed towards the site of stimulation. For example, sites near the base of a wing elicit anteriorly directed scratches, whereas sites near the distal end of a wing elicit posteriorly directed scratches. Locusts also scratch in response to tactile stimulation of a wing that is held outstretched in a posture similar to that normally adopted during flight, but they fail to alter their leg targeting to compensate for this changed position of the stimulus site. Instead, they scratch at an empty point in space near the abdomen, where the stimulus site would have been if the wing was folded in the resting posture. This inappropriate scratching does not result from mechanical constraints on the hindleg's movement, from stimulation of abdominal sensory receptors, or from an absence of sensory information from the outstretched wing. It also persists when the metathoracic ganglion that controls movements of the hindlegs is isolated from the remainder of the central nervous system (CNS). Targeted scratching of sites on the wings of locusts therefore appears to be fixed relative to body coordinates and does not take into account alterations of the target wing's position.


2020 ◽  
Vol 23 (10) ◽  
pp. 1182-1194
Author(s):  
A.A. Akhmetzyanov ◽  
A.Yu. Sokolov

Subject. The article focuses on the advanced time-driven tools for allocating overhead expenses, which are based on process-based budgeting. Objectives. We articulate a technique for cost allocation so as to assess the cost of each process with reference to the common time driver. Methods. The study relies upon methods of systematization, classification, analogy and comparison, and summarizes the scientific literature on the subject. Results. The article presents our own suggestions on implementing TD-ABC and TD-ABB into the strategic management accounting process of developer companies. The principles were proved to help more effectively allocate overhead expenses and assess the capacity load of each process performed by functions, departments and employees. Carrying out a comparative analysis, we found certain reserves for utilizing resources more effectively. Conclusions and Relevance. The findings are of scientific and practical significance and can be used by developer and construction businesses. The conclusions can prove helpful for scientific papers, student books, and further research.


2004 ◽  
Vol 32 (3) ◽  
pp. 337-355 ◽  
Author(s):  
Leslie Zines

This article originally was published as a Law and Policy Paper. The Law and Policy Papers series was established in 1994 by the Centre for International and Public Law in the Faculty of Law, the Australian National University. The series publishes papers contributing to understanding and discussion on matters relating to law and public policy, especially those that are the subject of contemporary debate. In 1999 the papers were published jointly by the Centre for International and Public Law and The Federation Press. This article is reproduced in the Federal Law Review with the permission of the original publishers.


Author(s):  
Justine Pila

This chapter considers the meaning of the terms that appropriately denote the subject matter protectable by registered trade mark and allied rights, including the common law action of passing off. Drawing on the earlier analyses of the objects protectable by patent and copyright, it defines the trade mark, designation of origin, and geographical indication in their current European and UK conception as hybrid inventions/works in the form of purpose-limited expressive objects. It also considers the relationship between the different requirements for trade mark and allied rights protection, and related principles of entitlement. In its conclusion, the legal understandings of trade mark and allied rights subject matter are presented as answers to the questions identified in Chapter 3 concerning the categories and essential properties of the subject matter in question, their method of individuation, and the relationship between and method of establishing their and their tokens’ existence.


2021 ◽  
Vol 11 (2) ◽  
pp. 21
Author(s):  
Julia V. Furtado ◽  
António C. Moreira ◽  
Jorge Mota

Gender affirmative action (AA) in management remains a controversial topic among scholars, practitioners, and employees. While some individuals may support the use of AA policies as a means of increasing representation of women, others are not supportive at all, further understanding gender AA as an unacceptable violation of merit—even when targeted by it. With the aim of analyzing how scholars have approached the subject, we systematically reviewed 76 published articles (SCOPUS database), covering the extant literature on gender AA and management. Findings indicate a consensus regarding the common antecedents of attitudes towards gender AA with prior experiences with AA and diversity management (DM) (as well as general perceptions of AA). Performance and satisfaction appear as the predominant outcomes. In addition, while investigating the differences among AA, equal employment opportunity (EEO) and diversity management (DM), scholars are mainly focused on the effectiveness of AA as a means of increasing the inclusion of minorities in general. We conclude that despite marginal studies on employees’ attitudes toward gender AA, there is a gap in the literature, particularly an absence of research on the bivalent position of meritocracy (or merit violation) as both an antecedent and outcome of attitudes towards AA, which deserves further scrutiny.


1973 ◽  
Vol 21 ◽  
pp. 3-7
Author(s):  
Helen Sawyer Hogg

The title of this talk is really just a different phrasing from one I have used at several IAU meetings on the subject of numbers and kinds of variables in globular clusters. To furnish this material, I have finished the Third Catalogue of Variables in Globular Clusters. Since many of you are coming to this Colloquium with new information, the Catalogue is in draft form with a request that corrections and additions be given me by October 2, after which the draft will go to the printer.The First Catalogue of Variables in Globular Clusters was published at this observatory in 1939 and the Second Catalogue in 1955. In 1966 appeared the excellent Catalogue of Variables South of Declination—29° by Fourcade, Laborde and Albarracin, with splendid large prints of identification charts.


1984 ◽  
Vol 35 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Robert Ombres

By the 1230s Latins and Greeks were riot short of issues for debate or polemic, but the topic of purgatory did have a novel feel about it. The doctrine seems to emerge on the common agenda fairly suddenly, finding no place, for example, in the wide-ranging list of 104 points of divergence drawn up by the Byzantine prelate, Constantine Stilbès, in the wake of the cruel sack of Constantinople by the Latins in 1204. The subject did, however, establish itself as a hardy perennial, and it is proposed to trace its main ramifications up to the death of Emperor Michael viii in 1282, and then to concentrate on the Council of Ferrara–Florence (1438–9). Without a doubt the debates and the constant attempts at reunion were not conducted in isolation from wider cultural, political and military considerations, the kind of considerations that in 1400 would lead the Byzantine emperor to journey as far as England. But here the emphasis will fall on the theological aspects. Moreover, there were also in play forces of inertia, ignorance and mutual incomprehension difficult to assess rationally. The thirteenth-century friar, Humbert of Romans O.P., in discussing what would make for reunion with the Greeks noted how a schism might be continued simply because it had existed for a long time, just like the feud between Guelf and Ghibelline.


1992 ◽  
Vol 67 (1) ◽  
pp. 3-16 ◽  
Author(s):  
Harri Hemilä

The effect of vitamin C on the common cold has been the subject of several studies. These studies do not support a considerable decrease in the incidence of the common cold with supplemental vitamin C. However, vitamin C has consistently decreased the duration of cold episodes and the severity of symptoms. The benefits that have been observed in different studies show a large variation and, therefore, the clinical significance may not be clearly inferred from them. The biochemical explanation for the benefits may be based on the antioxidant property of vitamin C. In an infection, phagocytic leucocytes become activated and they produce oxidizing compounds which are released from the cell. By reacting with these oxidants, vitamin C may decrease the inflammatory effects caused by them. Scurvy, which is caused by a deficiency in vitamin C, is mostly attributed to the decreased synthesis of collagen. However, vitamin C also participates in several other reactions, such as the destruction of oxidizing substances. The common cold studies indicate that the amounts of vitamin C which safely protect from scurvy may still be too low to provide an efficient rate for other reactions, possibly antioxidant in nature, in infected people.


When the nature of any saline compound is proposed as the subject of inquiry to an analytic chemist, the questions that occur for his consideration are so varied and so numerous, that he will seldom be disposed to undertake a series of original experiments for the purpose of satisfying his inquiries, so long as he can rely upon the accuracy of those results that have been obtained by the labour of others, who have preceded him in this field of patient investigation. If, for instance, the salt under examination be the common blue vitriol, or crystallized sulphate of copper, the first obvious questions are, (1) How much sulphuric acid does it contain? (2) How much oxide of copper? (3) How much water? He may not be satisfied with these first steps in the analysis, but may desire to know further the quantities (4) of sulphur, (5) of copper, (6) of oxygen, (7) of hydrogen. As means of gaining this information, he naturally considers the quantities of various reagents that may be employed for discovering the quantity of sulphuric acid, (8) how much barytes, (9) carbonate of barytes, or (10) nitrate of barytes, would be requisite for this purpose; (11) How much lead is to be used in the form of (12) nitrate of lead; and when the precipitate of (13) sulphate of barytes or (14) sulphate of lead are obtained, it will be necessary that he should also know the proportion which either of them contains of dry sulphuric acid. He may also endeavour to ascertain the same point by means of (15) the quantity of pure potash, or (16) of carbonate of potash requisite for the precipitation of the copper. He might also use (17) zinc or (18) iron for the same purpose, and he may wish to know the quantities of (19) sulphate of zinc, or (20) sulphate of iron that will then remain in the solution.


1970 ◽  
Vol 102 (9) ◽  
pp. 1163-1168 ◽  
Author(s):  
W. D. Seabrook

AbstractSchistocerca gregaria possess four neurones of giant fibre proportions within the abdominal ventral nerve cord. These fibres arise from single cell bodies in the terminal ganglionic mass and pass without interruption to the metathoracic ganglion. Fibres become reduced in diameter when passing through a ganglion. Branching of the giant fibres occurs in abdominal ganglia 6 and 7.


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