scholarly journals Variation and structure of the eyes in the desert locust, Schistocerca gregaria (Forskål)

1947 ◽  
Vol 134 (875) ◽  
pp. 245-272 ◽  
Keyword(s):  
Schistocerca Gregaria ◽  
Postembryonic Development ◽  
Compound Eyes ◽  
Brown Pigment ◽  
Desert Locust ◽  
Direct Sunlight ◽  
The Third ◽  
Third Stage ◽  
Visual Impact ◽  
The One

The compound eyes of the solitaria phase individuals of the desert locust, Schistocerca gregaria (Forskål), are vertically striped with mostly 6 and 7, rarely 5 and 8, dark brown stripes, and a number of cream-coloured interstripes. In phase gregaria the interstripes, which are more or less invaded by brown pigment, are partially or wholely masked, the eye in the latter case presenting an almost uniformly dark brown appearance. The postembryonic development of the striped eyes, is described stage by stage. There is no stripe at the time of hatching. In the 6-striped eye one stripe is developed in the first-stage hopper and, subsequently a stripe is added at each of the five moults. In the 7-striped eye the one-moult-one stripe relationship holds good in most stages, but the extra seventh stripe is produced in two ways: (i) By the addition of two stripes at the second moult (i. e. the third-stage hopper has four stripes instead of three); and (ii) by the interposition of an extra-moult, usually in the third stage and rarely in the fourth, during which a new stripe is added (stripe-positive extra-moult). But extra-moulting does not necessarily lead to the addition of a stripe; stripe-neutral extra-moults are not infrequent. The development of the dorsal spot and the subdorsal streak are described. The mechanism of growth and the homology and nomenclature of the stripes and interstripes are discussed. The structure of the compound eyes and the pigmentary basis of stripe formation are described, and their effects on vision in solitaria and gregaria individuals discussed. Vision is discussed on the basis of ommatidial structure and pigmentation. In gregaria eyes a perfect apposition image is formed, the image being sharply defined. An ‘anti-halation’ device, produced by the post-retinular layer of pigment, is present. The eye is suited for diurnal vision, and strong direct sunlight is not avoided. In solitaria eyes the image is of the apposition type in its mode of formation but of the superposition type in effect; it has been termed a ‘pseudo-superposition’ image, and is more diffuse but brighter than in gregaria eyes. The ‘anti-halation’ device is weak and ineffective. The eye is suited for vision in subdued light and perceives movements rather than sharp images. Solitaria individuals, especially hoppers, avoid strong, direct sunlight. The effects of these differences in vision on the behaviour of gregaria - and solitaria -phase individuals are as follows: the former, owing to mutual visual impact induced by the formation of sharp images, tend to be gregarious; and further, owing to the presence of light-absorbing mechanisms, they do not avoid strong sunlight; the latter, on the other hand, owing to the want or comparative ineffectiveness of the above-mentioned features, neither tend to congregate nor to go out boldly into the bright open.

scholarly journals The genesis of the legal regulation of the sale of land plots and rights to them on a competitive basis

2020 ◽  
pp. 264-269
Author(s):  
Diana Kolomiitseva
Keyword(s):  
Experimental Period ◽  
Legal Framework ◽  
Legal Regulation ◽  
Second Stage ◽  
The Third ◽  
Time Period ◽  
Legal Risks ◽  
Third Stage ◽  
The One ◽  
Land Code

The author identifies six main stages and outlines the peculiarities of legal regulation of the sale of land plots and rights to them on a competitive basis at each stage. The first stage was from 18 December 1990 to 28 June 1996; the second stage took place from 28 June 1996 to 1 January 2008, covering the period of adoption of the effective Land Code of Ukraine dated 25 October 2001; the third stage lasted from 28 December 2007 to 5 July 2012; the fourth stage was the stage of the development of competitive acquisition of rights to land plots covering the time period from 5 July 2012 to 21 June 2017; the fifth stage covered the experimental period from 21 June 2017 to 1 October 2019; the sixth stage has been going on since 1 October 2019. This periodization enables, firstly, to create a systematic view of the development of legal regulation of the competitive principles of acquiring rights to land plots under the land legislation of Ukraine; and secondly, to assess the legal risks of acquiring rights to land plots having been acquired in a period of time corresponding to the stage of legal regulation. The conducted analysis of the genesis of legal regulation of the sale of land plots and rights to them on a competitive basis indicates that in the circumstances of lack of legal framework for land auctions, the process of disposal of land plots and rights to them on a competitive basis have not been stopped. Each of the identified stages of legal regulation, except for the fourth one and the last one, has some contradictions in the source base bearing some legal risks for the contracts of sale of land plots on a competitive basis concluded at these stages. Like the Presidential Decrees at the first stage and the Regulation of the Cabinet of Ministers of Ukraine at the fifth stage, the decisions of local councils at the second and third stages were a means of and an attempt to accelerate the necessary changes in the land legislation. On the one hand, these regulatory acts are contrary to the provisions of the Land Code of Ukraine, and on the other hand, they are administrative acts that have been in force for a certain period of time and have not been repealed or deemed to be unconstitutional. Therefore, in making the legal evaluation of the agreements concluded on a competitive basis, they should be assessed taking into account the abovementioned factors.

The Histology and Histochemistry of Development and Resorption in the Terminal Oocytes of the Desert Locust, Schistocerca Gregaria

1963 ◽  
Vol s3-104 (65) ◽  
pp. 57-68
Author(s):  
O. LUSIS
Keyword(s):  
Corpus Luteum ◽  
Schistocerca Gregaria ◽  
The Body ◽  
Active Part ◽  
Desert Locust ◽  
Lipid Bodies ◽  
Follicular Cells ◽  
The Third ◽  
Postovulatory Follicle ◽  
Β Carotene

During vitellogenesis the follicular cells play an active part in the synthesis of yolk. The term ‘corpus luteum’ as applied to the ovary of the locust is invalid and two terms ‘white’ and ‘yellow’ follicle have been introduced to describe the separate identities of the normal and pathological postovulatory follicle. The protein yolk is a proteincarbohydrate compound, presumably a glycoprotein. Three kinds of lipid bodies are present; the first is a phospholipid, the second a combined phospholipid and triglyceride, and the third triglyceride. Lipids are coloured by dissolved β-carotene. Concentration or absorption of the lipids causes the crystallization of carotene and the formation of the pigment body. During resorption the follicular cells act as lecitholytic cells, first breaking down the protein and then the lipid yolk, and finally degenerating themselves. It is suggested that the oocytes have an inherent potential for resorption, the realization of which depends on various factors within the body.

scholarly journals طرق تعليم المحادثة في الهيئة اللغوية "الأزهار" بباري كديري جاوى الشرقية

2021 ◽  
Vol 10 (2) ◽  
pp. 35-51
Author(s):  
Nur Ainun Ritonga
Keyword(s):  
Problem Solving ◽  
Scientific Literature ◽  
Direct Method ◽  
Arabic Language ◽  
Foreign Languages ◽  
Second Stage ◽  
The Third ◽  
Third Stage ◽  
The One ◽  
Oral Method

The researcher observed Al-Azhar Course, the one of Arabic Courses in Pare Kediri, East Java that . The reasons for establishing this language body are to assist students in practicing foreign languages, especially Arabic. Its purpose is for students to be able to speak Arabic. Its goal is to upgrade the competence of the Arabic language for Muslims so that they can speak this language and understand the Qur’an and Hadith and understand scientific literature and others. And her vision is a person with knowledge, good deeds, and decent morals. Its mission is to spread the Arabic language as a means of shaping the Islamic person with enthusiasm, intelligence and noble morals. The programs in the linguistic body “Al-Azhar” are from the dorm and the classroom, such as the “distinction” class, the class for the first stage, the class for the second stage, the class for the third stage, the curriculum class, and vacation programs. The methods used to teach conversation material in this linguistic form “Al-Azhar” in Bari Kediri East Java and in the classroom for the second stage, especially as follows: the audio-oral method, the direct method, the crazy method, the rhetorical method, and the problem-solving method.

THE GENESIS OF LEGAL SUPPORT OF ACADEMIC VIRTUE

2020 ◽  
pp. 36-39
Author(s):  
I. Shopina
Keyword(s):  
Higher Education ◽  
Educational Activity ◽  
Ethical Values ◽  
The Third ◽  
Academic Responsibility ◽  
Third Stage ◽  
The One ◽  
Definition Of

The article is dedicated to the determination of the peculiarity of stages of legal support of academic virtue in Ukraine.It has been proven that the first stage for development of legal support to academic virtue has started in 2004, when the all-European processes of increasing the role of universities within a society have been initiated as well as the transformation ofrequirements to the participants of educational activity. This stage has been characterized by the acceptance of a Bucharestdeclaration on ethical values and principles of higher education in the European region (2-5 September 2004) and its result has been the establishment of an overall European discourse of academic virtue which included pedagogical, ethical and legalaspects of the phenomenon under research.It has been pointed out, that the third stage of legal support to academic virtue is related with stipulating in 2011 within aNational framework, the qualifications of adherence to proper academic virtue as the one that is considered to be necessary toinitiate, plan, implement and correct the subsequent process of a thorough scientific research of the level of basic skills andabilities. From this moment on there’s an active development of the terminological core dedicated to the issue of academicvirtue, there’s a preparation of suggestions to be implemented to the legislation on education, particularly, by determining thelegal definition of academic virtue, the forms and types of academic responsibility, and also the active reaffirming of ethicalrequirements on the academic virtues of teachers, scientists and individuals obtaining education in the codes of academicvirtues, approved in the course of gatherings of working teams or the scientific councils of universities.

Phase-related morphological changes induced by [His7]-corazonin in two species of locusts, Schistocerca gregaria and Locusta migratoria (Orthoptera: Acrididae)

2004 ◽  
Vol 94 (4) ◽  
pp. 349-357 ◽  
Author(s):  
K. Maeno ◽  
T. Gotoh ◽  
S. Tanaka
Keyword(s):  
Fore Wing ◽  
Morphological Traits ◽  
Schistocerca Gregaria ◽  
Morphological Changes ◽  
Locusta Migratoria ◽  
Hind Femur ◽  
Desert Locust ◽  
Maximum Width ◽  
Phase Polymorphism ◽  
The Third

AbstractThe effects of a neurohormone, [His7]-corazonin, on phase-related morphological traits (F/C and E/F ratios; F = length of the hind femur, C = maximum width of the head; E = length of fore wing) were re-examined in the desert locust, Schistocerca gregaria Forskål. The F/C ratio was significantly different between adults with five and six nymphal instars, respectively, indicating that they need to be analysed separately. Injections of the synthesized peptide (1 nmol) into individually-reared (solitary) nymphs at the second and third instars caused a shift in classical morphometric ratio towards the value typical for crowded (gregarious) individuals in both sexes. The E/F ratio, which is smaller in solitary locusts than in gregarious ones, was also influenced significantly by injections of [His7]-corazonin into individually-reared locusts. The effect of [His7]-corazonin on E/F ratios was shown more clearly when the nymphs were injected at a higher dose (2 nmol) at the beginning of the third instar. Single injections of the peptide into individually-reared nymphs at different instars revealed that the earlier the injection the larger the ‘gregarizing’ effects of the peptide on F/C and E/F ratios. The same tendency was also detected in Locusta migratoria Linnaeus. These results supported the hypothesis that [His7]-corazonin plays an important role in the control of phase polymorphism in locusts.

The cellular responses of migratory grasshoppers (Melanoplus sanguinipes F.) and African desert locusts (Schistocerca gregaria L.) to Diplotriaena tricuspis (Nematoda:Diplotriaenoidea)

1980 ◽  
Vol 58 (1) ◽  
pp. 109-113 ◽  
Author(s):  
Richard J. Cawthorn
Keyword(s):  
Schistocerca Gregaria ◽  
Fat Body ◽  
Fibrous Tissue ◽  
Cellular Responses ◽  
Melanoplus Sanguinipes ◽  
Capsule Wall ◽  
The Third ◽  
Third Stage

Twelve hours after infection first-stage larvae of Diplotriaena tricuspis (Nematoda:Diplotriaenoidea) had hatched, penetrated the gut wall, and entered lobules of the fat body of grasshoppers (Melanoplus sanguinipes F.) and African locusts (Schistocerca gregaria L.). Capsule development was similar in grasshoppers and locusts. Capsules, which had fibrous walls and contained both normal and degenerating adipocytes, developed at least as early as 4 days after infection. Capsules were well developed when the third stage was reached. The fibrous wall probably resulted from conversion of adipocytes to fibrous tissue. Larvae apparently had a readily available source of food (adipocytes) and were protected from the haemocytic response of the insect by the capsule wall. Larvae were not destroyed by haemocytes or melanization. Few larvae developed free in the haemocoele.

scholarly journals RNAi-Mediated Knockdown of Transcription Factor E93 in Nymphs of the Desert Locust (Schistocerca gregaria) Inhibits Adult Morphogenesis and Results in Supernumerary Juvenile Stages

2020 ◽  
Vol 21 (20) ◽  
pp. 7518
Author(s):  
Marijke Gijbels ◽  
Elisabeth Marchal ◽  
Thomas Wolf Verdonckt ◽  
Evert Bruyninckx ◽  
Jozef Vanden Broeck
Keyword(s):  
Schistocerca Gregaria ◽  
Fat Body ◽  
Total Duration ◽  
Early Response ◽  
Postembryonic Development ◽  
Early Gene ◽  
Pest Species ◽  
Desert Locust ◽  
Altered Expression ◽  
Transcript Levels

Postembryonic development of insects is coordinated by juvenile hormone (JH) together with ecdysteroids. Whereas the JH early response gene krüppel-homolog 1 (Kr-h1) plays a crucial role in the maintenance of juvenile characteristics during consecutive larval stages, the ecdysteroid-inducible early gene E93 appears to be a key factor promoting metamorphosis and adult morphogenesis. Here, we report on the developmental and molecular consequences of an RNAi-mediated knockdown of SgE93 in the desert locust, Schistocerca gregaria, a hemimetabolan species. Our experimental data show that injection of gregarious locust nymphs with a double-stranded RNA construct targeting the SgE93 transcript inhibited the process of metamorphosis and instead led to supernumerary nymphal stages. These supernumerary nymphal instars still displayed juvenile morphological features, such as a nymphal color scheme and body shape, while they reached the physical body size of the adult locusts, or even surpassed it after the next supernumerary molt. Interestingly, when compared to control locusts, the total duration of the fifth and normally final nymphal (N5) stage was shorter than normal. This appeared to correspond with temporal and quantitative changes in hemolymph ecdysteroid levels, as well as with altered expression of the rate-limiting Halloween gene, Spook (SgSpo). In addition, the levels of the ecdysone receptor (SgEcR) and retinoïd X receptor (SgRXR) transcripts were altered, indicating that silencing SgE93 affects both ecdysteroid synthesis and signaling. Upon knockdown of SgE93, a very potent upregulation of the SgKr-h1 transcript levels was observed in both head and fat body, while no significant changes were detected in the transcript levels of SgJHAMT and SgCYP15A1, the enzymes that catalyze the two final steps in JH biosynthesis. Moreover, the process of molting was disturbed in these supernumerary nymphs. While attempting ecdysis to the next stage, 50% of the N6 and all N7 nymphal instars eventually died. S. gregaria is a very harmful, swarm-forming pest species that destroys crops and threatens food security in many of the world’s poorest countries. We believe that a better knowledge of the mechanisms of postembryonic development may contribute to the discovery of novel, more selective and sustainable strategies for controlling gregarious locust populations. In this context, identification of molecular target candidates that are capable of significantly reducing the fitness of this devastating swarming pest will be of crucial importance.

scholarly journals Implied Reader Response and the Evolution of Genres: Transitional Stages Between the Ancient Novels and the Apocryphal Acts

1997 ◽  
Vol 53 (4) ◽  
Author(s):  
Robert M. Price
Keyword(s):  
Old Testament ◽  
Acts Of The Apostles ◽  
Second Stage ◽  
The Third ◽  
Apocryphal Acts ◽  
Third Stage ◽  
Three Stages ◽  
The Many ◽  
The One ◽  
Adventure Novels

This article aims at elaborating on the commonly held judgment that the Apocryphal Acts of the Apostles have somehow been influenced by the Hellenistic novels. It is argued that the one evolved from the other. Three stages can be traced. A first stage consists of Christian allegorizing of the novels based on the many striking crucifixion and empty tomb passages, followed by a second stage of writing Christian allegories based on the Old Testament heritage of Christianity. Joseph and Asenath being the sole surviving example. Finally, the third stage is the explicit composing of Christian versions of the picaresque romantic adventure novels, namely the Apocryphal Acts.

scholarly journals Estimating the Optimal Time for a Road Concession Contract in Brazil

2017 ◽  
Vol 9 (12) ◽  
pp. 44 ◽  
Author(s):  
Douglas Pivatto ◽  
Rodrigo Nobre Fernandez ◽  
Helton Saulo ◽  
Andre Carraro
Keyword(s):  
Road Networks ◽  
Optimal Time ◽  
The Third ◽  
Term Contract ◽  
Third Stage ◽  
The World ◽  
Three Stages ◽  
The One ◽  
Concession Contract

Brazil has one of the largest road networks managed under concession contracts in the world. The concessions of the Federal Concession Program are divided into three stages. The main aim of this research was to identify critical successful contracts from the Third Stage of the Concession Program. The methodology adopted follows the model proposed by Ng et al. (2007). This model verifies the probability at which the project will be successfully run within the term contract. The results showed a discrepancy between the time contractually agreed and the one simulated by the model for two of the seven contracts signed in the Third Stage of the Concession Program.

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