scholarly journals The Central Nervous Organization of the Motor Neurones to a Steering Muscle in Locusts

1986 ◽  
Vol 120 (1) ◽  
pp. 403-420
Author(s):  
HANS-JOACHIM PFLÜGER ◽  
ROBERT ELSON ◽  
ULRIKE BINKLE ◽  
HENNING SCHNEIDER
Keyword(s):  
Cell Body ◽  
Morphological Features ◽  
Dorsal Region ◽  
The Third ◽  
Motor Neurones ◽  
Flight Motor ◽  
Large Muscle ◽  
Muscle Potential

1. The pleuroaxillary or pleuroalar muscles of the locust (M85, Ml 14) are located in the meso- and metathoracic segments only. Each extends from the posterior face of the pleural ridge and runs dorsally and obliquely, inserting on the third axillary sclerite of the wing hinge. Each muscle consists of two distinct parts, a and b (Fig. 1). 2. Each pleuroaxillary muscle is innervated by two motor neurones which give rise to a small and a large muscle potential in electromyogram recordings (Fig. 6E). The cell body of each neurone lies posteriorly in the ganglion and the axon runs out in nerve 4 (Figs 3–6). 3. The two motor neurones of a particular muscle share many common morphological features (Figs 3–6). There is also clear segmental homology between the motor neurones supplying the meso- and metathoracic muscles (Fig. 3). 4. Serial transverse sections of the motor neurones show that their arborization is confined mainly to a dorsal region of the neuropile. Some of the collaterals encompass, and terminate in, dorsal longitudinal tracts. Branching extends far anteriorly. Posteriorly, one secondary neurite runs ventrally (Figs 7, 8). A few secondary and tertiary neurites of the metathoracic pleuroaxillary motor neurones terminate within the neuropile of the first abdominal neuromere (Figs 6, 8). Additional features which distinguish these neurones from other flight motor neurones are discussed.

scholarly journals The Identification of Motor Neurones Innervating an Abdominal Ventilatory Muscle in the Locust

1983 ◽  
Vol 107 (1) ◽  
pp. 115-127 ◽  
Author(s):  
QIN-ZHAO YANG
Keyword(s):  
Cell Body ◽  
Contralateral Side ◽  
The Body ◽  
Dorsal Muscle ◽  
The Third ◽  
Metathoracic Ganglion ◽  
Motor Neurones ◽  
Left And Right ◽  
Ventral Muscle ◽  
Ventilatory Muscles

Motor neurones to abdominal ventilatory muscles, with their axons innerve 6 of the metathoracic ganglion of the locust, have been identified by intracellular recording and staining. Three muscles are innervated by the larger branches of this nerve: nerve 6a contains six motor neurones innervating the ventral diaphragm; nerve 6b contains four motor neurones innervating the median internal ventral muscle, and nerve 6d contains five motorneurones innervating the longitudinal dorsal muscle. All motor neuronesinnervate muscles on one side of the body only. Both the median internalventral and the longitudinal dorsal muscles contract during the expiratoryphase of ventilation. Three excitatory motor neurones to the median internalventral muscles spike during expiration whilst the fourth, an inhibitorymotor neurone, is active during both expiration and inspiration. Two of theexcitatory motor neurones have cell bodies in the half of the ganglion ipsilateralto the muscle they innervate. Their neuropilar branches, however, are in both left and right halves of the ganglion. The third excitatory motorneurone has its cell body close to the midline and has most of its neuropilarbranches in the half of the ganglion ipsilateral to its axon. The inhibitorymotor neurone has its cell body just to the contralateral side of the midline, and three distinct areas of neuropilar branches, two contralateral and oneipsilateral to its axon.

scholarly journals The Segmental Giant Neurone of the Hermit Crab Eupagurus Bernhardus

1986 ◽  
Vol 125 (1) ◽  
pp. 245-269 ◽  
Author(s):  
W. J. Heitler ◽  
K. Fraser
Keyword(s):  
Cell Body ◽  
Hermit Crab ◽  
Small Cell ◽  
Electrical Synapse ◽  
Giant Fibre ◽  
Anatomy And Physiology ◽  
Motor Neurones ◽  
Evolutionary Paths ◽  
Contralateral Motor ◽  
Giant Fibre System

The anatomy and physiology of the segmental giant (SG) neurone of the fourth abdominal ganglion of the hermit crab is described. The SG has an apparently blindending axon in the first root and a small cell body in the anterior ipsilateral ventral quadrant of the ganglion. There is a large ipsilateral neuropile arborization with prominent dendrites lined up along the course of the ipsilateral giant fibre (GF). The SG receives 1:1 input from the ipsilateral GF via an electrical synapse which is usually rectifying. SG activation produces a large EPSP in all ipsilateral and some contralateral fast flexor excitor (FF) motor neurones. The major input to FFs resulting from GF activation appears to be mediated via the SG. It also produces a small EPSP in ipsilateral and contralateral motor giant neurones. The properties of the hermit crab SG are compared to those of the crayfish SG, and the implications of the SG for the possible evolutionary paths of the giant fibre system are discussed.

Secular Architecture: Military

2021 ◽  
pp. 362-372
Author(s):  
Stavros I. Arvanitopoulos
Keyword(s):  
Systematic Study ◽  
Daily Life ◽  
Morphological Features ◽  
Sixth Century ◽  
Third Century ◽  
The Third ◽  
Selection Of

The Byzantine state inherited a large number of defensive structures, on its borders and in the hinterland where ancient cities were refortified in response to barbarian raids, primarily during the third century. The fundamental characteristics of fortification architecture developed during the sixth century. Nevertheless, criteria for the selection of the location, dimensions, and certain construction and morphological features of the forts, towers, and city/barrier walls, were continually adapted to changes in society and state until the end of the empire. Systematic study of the defensive architectural remains including excavation, creation of synthetic works, and reliable maps will allow researchers to date, compare, and understand the evolution of fortification architecture as well as aspects of daily life in the empire.

scholarly journals Morphological features of the leaves in clematises as a reflection of their ecological peculiarities

2021 ◽  
Vol 89-90 ◽  
pp. 89-100
Author(s):  
Iryna Kovalyshyn ◽  
Andrii Pinchuk ◽  
Artur Likhanov
Keyword(s):  
Leaf Area ◽  
Anatomical Structure ◽  
Morphological Features ◽  
Adaxial Surface ◽  
Anatomical Features ◽  
The Third ◽  
Small Leaf ◽  
Significant Difference ◽  
Windy Weather

Quantitative morpho-anatomical features of leaves of nine Clematis taxa (C. alpina ‘Pamela Jackman’, C. macropetala ‘Maidwell Hall’, C. integrifolia ‘Aljonushka’, C. ispahanica ‘Zvezdograd’, C. fargesii ‘Paul Farges’, C. texensis ‘Princess Diana’, C. tibetana, C. viticella, and C. heracleifolia) were determined with the aim to analyze their adaptation to the environmental conditions.Among investigated clematises, there were plants with hypostomatic (C. viticella, C. fargesii ‘Paul Farges’, C. heracleifolia, C. texensis ‘Princess Diana’, C. macropetala ‘Maidwell Hall’, and C. alpina ‘Pamela Jackman’), and amphistomatic leaves (C. ispahanica ‘Zvezdograd’ and C. tibetana). In C. integrifolia ‘Aljonushka’ leaves were hypostomatic, but few solitary stomata were also present on the adaxial surface. In the leaves of investigated taxa, the palisade coefficient ranged from 27.3% (C. alpina ‘Pamela Jackman’) to 49.9% (C. tibetana). The leaves also differed significantly in size. In particular, leaves of C. integrifolia ‘Aljonushka’ were almost ten times smaller than such of C. heracleifolia.As a result of UPGMA clustering, the plants that can survive in severe windy weather in open rocky areas, Clematis tibetana and C. ispahanica ‘Zvezdograd’, were joined in a separate cluster. The second cluster combined C. alpina ‘Pamela Jackman’ and C. macropetala ‘Maidwell Hall’ – cultivars blooming in the spring, during a period of significant difference in daily temperatures. A relatively small leaf area in plants from these two clusters may indicate an adaptation by reducing the transpiration area and general windage. The third cluster united the rest of investigated taxa, mostly – the mesophytic plants with a relatively large leaf area. However, due to similar morpho-anatomical structure of the leaf, the third cluster also comprised C. integrifolia ‘Aljonushka’ with the smallest leaves.

scholarly journals Rodent Suborders

2019 ◽  
Vol 75 (3-4) ◽  
pp. 292-298
Author(s):  
Lawrence J. Flynn ◽  
Louis L. Jacobs ◽  
Yuri Kimura ◽  
Everett H. Lindsay
Keyword(s):  
Future Study ◽  
Molecular Basis ◽  
Morphological Character ◽  
Morphological Features ◽  
The Third ◽  
Molecular Studies ◽  
The Status ◽  
Character Complexes ◽  
Rodent Phylogeny ◽  
Formal Recognition

Abstract For two hundred years the status of rodent suborders has been unstable. What are the natural groupings of extant rodent families? The formal recognition of rodent suborders has remained challenging and consensus has been elusive. Classically conceived rodent suborders are widely viewed as artificial, but no universally accepted classification has emerged to reflect the major features of rodent evolution. Over the last two decades molecular studies have established that extant rodents comprise three monophyletic clades. We review the molecular basis for these groups and recognize them as taxonomic units: Suborder Ctenohystrica Huchon et al., 2000, Suborder Supramyomorpha D’Elía et al., 2019, and a group of families clustered with Sciuridae. The latter differs from Sciuromorpha as traditionally conceived because the suborder includes Aplodontiidae but excludes Castoridae. We review morphological character complexes that are distributed broadly within these three clades, name the third group Eusciurida, new suborder, and find this three-fold division of extant Rodentia to reflect well the major features of rodent phylogeny. That some morphological features do not characterize all families within suborders, or are not unique to individual suborders, indicates major parallel innovations and reversals in rodent evolution. These incongruent morphologies invite future study.

Ieskats Virgas izloksnes fonētikā un morfoloģijā

2020 ◽  
pp. 114-121
Author(s):  
Liene Markus-Narvila
Keyword(s):  
21St Century ◽  
Morphological Features ◽  
Past Tense ◽  
Primary Material ◽  
The Third ◽  
The Past ◽  
Depth Analysis ◽  
Third Person ◽  
The Stability ◽  
The Third Person

Virga subdialect is one of the subdialects of Southwestern Kurzeme, which belongs to Semigallian subdialects of the Middle Latvian dialect. The characteristics of Virga subdialect can be traced by using mostly three sources: materials of Latvian folklore, the compiled answers to the questions of the Dialectal Atlas of Latvian collection programme, and collected texts of the subdialects, including the materials of expeditions in Virga subdialect collected in the 21st century. These three sources are the primary material for the article. The phonetic and morphological features of Virga subdialect are generally consistent with the phonetical and morphological features typical throughout the Southwestern Kurzeme region. The sections of the article focus on the typical and most representative features in phonetics and morphology of Virga subdialect and reveal their relationship with the typical features of the subdialects used in the whole area. Phonetics of Virga subdialect is characterised by the use of broad e, ē in infinitives, palatal consonant ŗ, assimilation of ln to ll, the loss of sounds in different positions, anaptyxis, and vowel extension before the consonant r. Morphology of Virga subdialect is characterised by the abbreviation of verbs (ne)būt, (ne)iet in the past tense, the third person; ē-stem substantives; āio-stem verbs; the use of suffix ūz-. In the future, further research of Virga subdialect is important in order to determine the stability of the use of the registered features and register other features of the subdialect. Studies of the nearest neighbouring subdialects should also be carried out to allow a wider scientific in-depth analysis of the subdialects used in the area.

/ka-/ negative prefix of Choswateng Tibetan of Khams (Shangri-La, Yunnan)

2021 ◽  
Vol 22 (4) ◽  
pp. 593-629
Author(s):  
Hiroyuki Suzuki ◽  
Lozong Lhamo
Keyword(s):  
Morphological Feature ◽  
Morphological Features ◽  
The Self ◽  
The Other ◽  
The South ◽  
Rhetorical Question ◽  
The Third ◽  
South Eastern

Abstract Choswateng Tibetan, spoken in the south-eastern corner of the Khams region, has three negative prefixes: /ȵi-/, /ma-/, and /ka-/. The first two are derived from two morphemes which are ubiquitous across Tibetic languages, whereas the third is a newly generated negative prefix found in Choswateng Tibetan as well as its surrounding dialects belonging to the rGyalthang subgroup of Khams and its neighbours. This article describes the morphological feature and use of the prefix /ka-/ in Choswateng Tibetan. Morphologically, the prefix /ka-/ can co-occur with most verbs except for the copulative verb /ˊreʔ/. Pragmatically, the prefix /ka-/ occurs and is restricted in the following ways: (1) expresses ‘definitely not’ for statements regarding the self, and ‘possibly not, judging from the speaker’s knowledge’ for statements regarding others; (2) co-occurs with egophoric and sensory evidentials; (3) is not used for a negation of accomplished aspect; and (4) does not deprive the function of the other two negative prefixes. These two analyzes are mutually related; it is suggested that the reason why /ka-/ cannot co-occur with the copulative verb /ˊreʔ/ is triggered by a contradiction of implied evidentials: /ka-/ is related to egophoric and sensory, whereas /ˊreʔ/ is statemental. Following the description of its use, we discuss the origin of /ka-/, claiming a possible grammaticalization from an interrogative word gar (‘where’ in Literary Tibetan and common throughout the rGyalthang area) in a rhetorical question to a prefix. Referring to several morphological features of /ka-/, we consider its grammaticalization as ongoing, but most advanced in Choswateng Tibetan.

Mesolithic Lake Cultures in the Ganga Valley, India

1973 ◽  
Vol 39 ◽  
pp. 129-146 ◽  
Author(s):  
G. R. Sharma
Keyword(s):  
Sandy Soil ◽  
Alluvial Plain ◽  
Morphological Features ◽  
Wide Area ◽  
Stone Age ◽  
Plastic Clay ◽  
Clay Deposit ◽  
The Third ◽  
The North ◽  
Sandy Deposit

The explorations conducted by the Institute of Archaeology, Allahabad University, in the last few years in the alluvial plain of the Central Ganga Valley, bounded by the Ganga on the south and the Sarju on the north, have brought to light extensive traces of Stone Age occupation in an area completely devoid of rocks. The work has also revealed the connection between this appearance of early man and the morphological features brought about by the changing course of the Ganga in the Pleistocene. The Gangetic alluvial is clearly divided into two distinct formations, the older known as Bhagar, and the younger as Khadar. The terminal of the Bhagar constituted the bank of the Ganga when it was actually forming this area and gradually receding southwards to form the deposit of the Khadar. Over a very wide area the exposed sections of the Bhagar (fig. 1) consist of four layers having a thickness of 8 to 10·5 m. On the top there is a sandy soil (30 cm to 1·50 m) overlying a plastic clay deposit (90 cm to 2 m in thickness). The third layer is constituted by blackish soil (1·50 m to 3 m) full of small kankar nodules. The bottommost exposed layer or the fourth (2 m to 4 m) from the top, containing kankars, is yellowish in colour. There is no doubt that the sandy deposit capping the old formation marks the end of an epoch in the life of the Ganga, and it was deposited by the river with a flood-plane higher by at least 10 metres than its highest flood-plane subsequently recorded.

Studies in the Australian Acacias—I. General Introduction*

1933 ◽  
Vol 49 (328) ◽  
pp. 133-143 ◽  
Author(s):  
I. V. Newman
Keyword(s):  
Morphological Features ◽  
First Principle ◽  
General Introduction ◽  
Phylogenetic Classification ◽  
The Third ◽  
The Common ◽  
Theoretical Considerations

SUMMARY In the studies to which this paper is an introduction, the genus Acacia (‘Wattles’, in Australia) will be carefully revised, the aim being to establish a phylogenetic classification of the genus as it occurs in Australia. Previous classifications are regarded as too static in conception. These Studies will seek to develop a kinetic conception. Features of the genus have a bearing on the theories of carpel polymorphism (Saunders), phylloclade legume (Thompson), leaf forms (Zimmermann). The position of the genus Acacia in the Leguminosae is briefly reviewed. The existing classification of the genus is found to be usually made with foliar or other vegetative features as the first principle of division. This is regarded as unsatisfactory. The contemporary and geological distribution of the genus is briefly reviewed. The variety of the habit of the genus, the recapitulatory features of the seedlings, and the common morphological features are referred to. An attempt is made to formulate a phylogenetic classification, based on the relationships of the flower-groups in the inflorescence as the first principle of division, on the relationships of the flowers in the flower-groups as the second principle of division, and on the foliar character as the third principle of division. The theoretical considerations underlying this scheme are presented, together with some already-known phenomena of the genus which support it. The scheme explains the occurrence of difficulties experienced in placing species in existing classifications. There is given a list of species selected for examination.

Morphology of inhibited larvae of the bovine lungworm Dictyocaulus viviparus

1999 ◽  
Vol 73 (1) ◽  
pp. 79-83 ◽  
Author(s):  
G. von Samson-Himmelstjerna ◽  
T. Schnieder
Keyword(s):  
Post Infection ◽  
Morphological Features ◽  
Fourth Stage ◽  
Dictyocaulus Viviparus ◽  
The Third ◽  
Third Stage

Some morphological features of inhibited fourth stage (L4) and fourth moult larvae (4M) of the bovine lungworm Dictyocaulus viviparus are described. Inhibition was induced by maintaining the third stage larvae (L3) for 6 weeks at 4°C. Inhibited fourth stage (L4) and fourth moult larvae (4M) were collected by perfusion of the lungs of experimentally infected calves after necropsy at 15 and 68 days post infection (d.p.i.), respectively. Inhibited 4M, isolated at 68 d.p.i., were about ten times larger than inhibited L4 isolated at 15 d.p.i.

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