Generation Of Different Forms Research Articles

Dynamical Evolution of Sasa–Satsuma Rogue Waves, Breather Solutions, and New Special Wave Phenomena in a Nonlinear Metamaterial

Herein, the behavior of the soliton light pulse when quintic –nonlinearity, third‐order dispersion, and self‐steepening come into play in a nonlinear metamaterial for both negative index and absorption regimes is presented. The collective coordinate technique is used with the conventional Gaussian ansatz function to give a good characterization of the pulse profile. In addition to that the ansatz function presents six coordinates describing the internal behavior of the pulse during the propagation. Furthermore, the main goal of this work is to give an exact measure of the internal behavior leading to the generation of rogue events by collective coordinates. Some interesting results are found when the aforementioned linear and nonlinear effects gradually come into play. Among them is the generation of different forms of breather solutions, divergent wave trains, different forms of Sasa–Satsuma rogue waves, parabolic wave trains, Peregrine rogue waves, and “tree structures”. Some special phenomena known as deletion, translation, attenuation, and wall of waves are also shown. However, some new exact rogue solutions of the cubic–quintic nonlinear Schrödinger equation are also found.

Natural Tensions in Aristotle’s Polis and Their Contemporary Manifestations

In this paper, I perform an analysis of Aristotle’s organic analogy when discussing the different “organs” of the Greek polis. I argue that this analysis demonstrates that the proper functioning of the polis depends upon the generation of different forms of life that will incline towards tension with one another, due to the fact that some members will be prevented by their form of life from enjoying the chief virtue of political life, namely, the accomplishment of human virtue and the good life. I argue that, at least within the context of the polis, there remains the possibility that those disenfranchised people experience sensuous recognition that they are contributing to human thriving. I contrast this with the modern city, in which what existed as a natural and visible tension in the polis becomes a concealed tension, with the result that no such recognition is possible, leaving modern city-dwellers alienated from the conditions that generate their forms of life.

Study on the Control Strategy of the Third Frequency Adjustment with the Participation of the Nuclear Power

The third frequency adjustment is the key link of the grid frequency regulation. The admission of high capacity and rejection of small capacity policy on thermal power cause the lack of capacity of the third frequency adjustment. Wind power brings about a certain impact to the frequency stability of the power system, particularly, increasing the difficulty of the third frequency adjustment. The introduction of nuclear power into the third frequency adjustment has been proposed after analyzing the characteristics of the energy generation of different forms. This paper formulate the control strategy with the core of wind power decomposition, generator units grouping in the third frequency adjustment, after elaborating the technical feasibility and economic feasibility, and, come to a conclusion that the participation of the nuclear in the third frequency adjustment would guarantee the stability of the frequency of the power system with this control strategy in the case of the introduction of wind power to the system, by simulation analysis.

The role of synoptic‐scale features and advection in prolonged warming and generation of different forms of precipitation at Dome Fuji station, Antarctica, following a prominent blocking event

A blocking event over the East Antarctic ice sheet during June 1997 generated the highest surface air temperature (which increased from around −70°C to around −30°C) and pressure of that year at the Dome Fuji station (77.5°S, 40°E). Following the blocking event, the anomalously high air temperature (around −50°C to −60°C) and pressure were maintained at the surface for about 1 week. This study investigates how these warm conditions were maintained and documents the sequential occurrence of two forms of synoptic‐scale high‐pressure systems with conditions that produced precipitation by different processes in each case. In the first half of the warm period, a solitary high‐pressure system (the Solitary High) formed over the Dome Fuji station and traveled west over East Antarctica after being cut off from the tip of the preceding blocking ridge. During this phase, tropospheric temperatures were higher, and surface‐based temperature inversions were more intense than during the following period. While a dry‐out developed in the troposphere below about 300 hPa, the precipitation of ice crystals in the surface‐based temperature inversion layer was generated by deposition of moisture that had become trapped in the boundary layer after being transported onto the continent by the previous blocking ridge. This mechanism has not been previously reported elsewhere. During the second half of the warm period, a ridge of high pressure (the Transcontinental Ridge) traversed East Antarctica almost completely, and its western section was amplified by the merging of the Solitary High with a preceding quasi‐stationary Rossby wave train propagating along the Southern Ocean. This ridge allowed an intrusion of warm, moist air from the Weddell Sea toward the station, which generated precipitation throughout the whole troposphere by orographic uplift once again, and ended the dry‐out. This represents the typical mechanism of both moisture transportation and the generation of precipitation, and this mechanism was the same as that associated with the preceding blocking ridge.

Activation of alpha‐2 noradrenergic receptors is critical for the generation of fictive eupnea and fictive gasping inspiratory activities in mammals in vitro

Biogenic amines are not just 'modulators', they are often essential for the execution of behaviors. Here, we explored the role of biogenic amines acting on the pre-Bötzinger complex (pre-BötC), an area located in the ventrolateral medulla which is critical for the generation of different forms of breathing. Isolated in transverse slices from mice, this region continues to spontaneously generate rhythmic activities that resemble normal (eupneic) inspiratory activity in normoxia and gasping in hypoxia. We refer to these as 'fictive eupneic' and 'fictive gasping' activity. When exposed to hypoxia, the pre-BötC transitions from a network state relying on calcium-activated nonspecific cation currents (I(CAN)) and persistent sodium currents (I(Nap)) to one that primarily depends on the I(Nap) current. Here we show that in inspiratory neurons I(Nap)-dependent bursting, blocked by riluzole, but not I(CAN) -dependent bursting, required endogenously released norepinephrine acting on alpha2-noradrenergic receptors (α2-NR). At the network level, fictive eupneic activity persisted while fictive gasping ceased following the blockade of α2-NR. Blockade of α2-NR eliminated fictive gasping even in slice preparations as well as in inspiratory island preparations. Blockade of fictive gasping by α2-NR antagonists was prevented by activation of 5-hydroxytryptamine type 2A receptors (5-HT2A). Our data suggest that gasping depends on the converging aminergic activation of 5-HT2AR and α2-NR acting on riluzole-sensitive mechanisms that have been shown to be crucial for gasping.

Photosensitization of CdSe/ZnS QDs and reliability of assays for reactive oxygen species production

CdSe/ZnS quantum dots (QDs) conjugated to biomolecules that can act as electron donors are said to be "photosensitized": that is, they are able to oxidize or reduce molecules whose redox potential lies inside their band edges, in particular molecular oxygen and water. This leads to the formation of reactive oxygen species (ROS) and phototoxicity. In this work, we quantify the generation of different forms of ROS from as-synthesized QDs in toluene; water-solubilized, unconjugated QDs; QDs conjugated to the neurotransmitter dopamine; and dopamine alone. Results of indirect fluorescent ROS assays, both in solution and inside cells, are compared with those of spin-trap electron paramagnetic resonance spectroscopy (EPR). The effect of these particles on the metabolism of mammalian cells is shown to be dependent upon light exposure and proportional to the amount of ROS generated.

Modifications of Locomotor Pattern Underlying Escape Behavior in the Lamprey

Two forms of undulatory locomotion in the lamprey (a lower vertebrate) have been described earlier: fast forward swimming (FFS) used for long distance migrations and slow backward swimming (SBS) used for escape from adverse tactile stimuli. In the present study, we describe another form of escape behavior: slow forward swimming (SFS). We characterize the kinematic and electromyographic patterns of SFS and compare them with SBS and FFS. The most striking feature of SFS is nonuniformity of shape and speed of the locomotor waves propagating along the body: close to the site of stimulation, the waves slow down and the body curvature increases several-fold due to enhanced muscle activity. Lesions of afferents showed that sensory information critical for elicitation of SFS is transmitted through the dorsal roots. In contrast, sensory signals that induce SBS are transmitted through the dorsal roots, lateral line nerves, and trigeminal nerves. Persistence of SFS and SBS after different lesions of the spinal cord suggests that the ascending and descending pathways, necessary for induction of SBS and SFS, are dispersed over the cross section of the spinal cord. As shown previously, during FFS (but not SBS) the lamprey maintains the dorsal-side-up body orientation due to vestibular postural reflexes. In this study we have found that the orientation control is absent during SFS. The role of the spinal cord and the brain stem in generation of different forms of undulatory locomotion is discussed.

Mediatorwirkungen im trigeminovaskulären System als Grundlage für die nozizeptiven Vorgänge bei der Kopfschmerzentstehung

Nociceptive mechanisms in the trigeminovascular system are probably involved in the generation of different forms of hedaches, wherein the neuropeptide CGRP (calcitonin gene-related peptide), which is released from a subset of activated primary afferents, is regarded as an important mediator. CGRP is not only a potent vasodilator but is also involved in nociceptive transmission in the trigeminal nucleus. Inhibition of CGRP receptors by the high-affinity CGRP receptor antagonist BIBN4096BS, which had proved its therapeutic potency in migraine patients, led to a significant decrease in neuronal activity in the spinal trigeminal nucleus of the rat. Another important vasodilatory mediator in meningeal nociception seems to be nitric oxide (NO), which may facilitate CGRP release from peripheral and central trigeminal structures. Inhibition of NO generation was effective in lowering the neuronal activity in the spinal trigeminal nucleus as well, whereas infusion of NO donors led to an increase in activity. The activiation showed typically a biphasic pattern. The delayed response can only be explained by secondary processes such as the expression of pro-nociceptive substances in the trigeminal nucleus or ganglion, as indicated by preliminary experimental studies. The fact that clinical and basic experimental data complement each other highlights the interpretative value of basic experiments for the pathophysiological mechanisms underlying the generation of headaches.

Pattern of Motor Coordination Underlying Backward Swimming in the Lamprey

The main form of locomotion in the lamprey (a lower vertebrate, cyclostome) is forward swimming (FS) based on periodical waves of lateral body flexion propagating from head to tail. The lamprey is also capable of backward swimming (BS). Here we describe the kinematical and electromyographic (EMG) pattern of BS, as well as the effects on this pattern exerted by different lesions of the spinal cord. The BS was evoked by tactile stimulation of a large area in the anterior part of the body. Swimming was attributed to the waves of lateral body undulations propagating from tail to head. The EMG bursts on the two sides alternated, and the EMG in more caudal segments led in phase the EMG in more rostral segments. Main kinematical characteristics of BS strongly differed from those of FS: the amplitude of undulations was much larger and their frequency lower. Also, the maintenance of the dorsal-side-up body orientation ascribed to vestibular postural reflexes (typical for FS) was not observed during BS. A complete transection of the spinal cord did not abolish the generation of forward-propagating waves rostral to the lesion. After a lateral hemisection of the spinal cord, the BS pattern persisted on both sides rostral to the lesion; caudal to the lesion, it was present on the intact side and reduced or abolished on the lesioned side. The role of the spinal cord in generation of different forms of undulatory locomotion (FS and BS) is discussed.

Pattern and Regulation of Acetyl-CoA Carboxylase Gene Expression1–3

Acetyl-CoA carboxylase is the rate-limiting enzyme in the biogenesis of long chain fatty acids. There is a single copy of the gene for acetyl-CoA carboxylase per haploid chromosome set. The gene contains two promoters whose primary transcripts are differentially spliced resulting in multiple forms of acetyl-CoA carboxylase mRNA. These mRNA species are different in the 5'-untranslated region, but contain the same coding region. Generation of different forms of the mRNA is tissue specific and controlled by physiological conditions. Two promoters contain an extensive array of cis-elements that perceive changes in the cellular environment signalling repression and induction of long chain fatty acid synthesis. The ability of the gene to respond to various lipogenic signals and the presence of the same coding sequence in all acetyl-CoA carboxylase mRNA species suggest that the biosynthesis of fatty acids required for multiple functions in the cells is primarily regulated at the gene level.

Roles of CCAAT/enhancer-binding protein and its binding site on repression and derepression of acetyl-CoA carboxylase gene.

The gene for acetyl-CoA carboxylase, the rate-limiting enzyme in the biosynthesis of long-chain fatty acids, contains two distinct promoter regions, denoted PI and PII, which control the generation of different forms of mRNA. Multiple forms of acetyl-CoA carboxylase (ACC) mRNA with 5'-end heterogeneity are generated as a result of differential splicing of two primary transcripts formed under the control of these two promoters. PI is responsible for the generation of class I mRNAs of ACC, which are induced in a tissue-specific manner under lipogenic conditions. PII generates class II mRNAs of ACC, which are expressed constitutively. Possible mechanisms for the regulation of PI under normal physiological conditions and agents that activate the promoter have been investigated. PI contains a TATA and a CCAAT box. In addition to these sequences, this promoter contains a 28-CA repeat sequence 220 bases upstream from the transcription initiation site; the presence of this sequence leads to about 70% repression of the basal promoter activity. Repression by the 28-CA repeat sequence requires the GCAAT sequence in the CCAAT box. The negative effect of the 28-CA repeat sequence is relieved by a CCAAT/enhancer-binding protein (C/EBP), which binds to the GCAAT sequence. Insertion of the 28-CA repeat sequence into the thymidine kinase promoter results in repression that can also be relieved by the C/EBP gene product. However, the same sequence exerts no effect on ACC promoter II, which has no CCAAT box. During the differentiation of 30A5 preadipocytes into adipocytes, the expression of class I ACC mRNA and C/EBP mRNA is coordinately increased. Therefore, the presence of the CA repeat in the promoter may be responsible for the inactivity of PI, and C/EBP may be one of the factors that is responsible for the activation of PI under lipogenic conditions. Interaction of the CA repeat and the CCAAT box in the repression and derepression of the ACC gene provides a novel function for the CCAAT box and C/EBP in gene regulation.

An enhancer element in the house-keeping promoter for acetyl-CoA carboxylase gene

The gene for acetyl-CoA carboxylase, the rate-limiting enzyme in the biogenesis of long chain fatty acids, contains two promoter regions which control the generation of different forms of carboxylase mRNA. At least five different forms of carboxylase mRNA are generated by differential splicing of the two transcripts formed under the influence of two promoters. One of the two promoters is mainly responsible for the generation of a class of carboxylase mRNA species, pAU type, induced tissue specifically under lipogenic conditions; the other generates ACC mRNAs (FL-type) which are expressed under normal conditions but this expression is also stimulated under lipogenic conditions. In the present studies, we have characterized the promoter that is responsible for the FL-type of ACC mRNA. This promoter contains no TATA or CAAT boxes, but five G/C motifs whose sequences are typical of transcriptional factor Sp1 binding sites. However, the presence of these G/C motifs is not sufficient to drive the transcription of the gene under the control of this promoter. Expression of promoter activity requires three copies of 11 to 13mer enhancer elements which are located in the region upstream to the G/C motifs. The presence of such enhancer elements in a house-keeping gene is unusual, and provides a new example where an enhancer element occurs in the CpG island-type promoter of a house-keeping gene.

Structural features of the acetyl-CoA carboxylase gene: mechanisms for the generation of mRNAs with 5' end heterogeneity.

Acetyl-CoA carboxylase [acetyl-CoA:carbondioxide ligase (ADP-forming), EC 6.4.1.2] is the rate-limiting enzyme in the biogenesis of long-chain fatty acids. We have previously characterized five acetyl-CoA carboxylase mRNA species that differ in their 5' untranslated regions but not in the coding region. We have now characterized the exon-intron structure of the genomic DNA that encodes the 5' untranslated region of the mRNA. Generation of different forms of the mRNA is the result of the selective use of two promoters and differential splicing of five different exons. These five exons contain a total of 645 nucleotides and they are scattered over a 50-kilobase-pair genomic DNA region that we have characterized.