Presence Of Connections Research Articles

Vieillissement et Demence de Type Alzheimer: influence du type de connecteur sur la comprehension et la memorisation de phrases

Le but de cette étude est d'examiner l'effet de différents types de connecteur (causal, adversatif, additif) sur la compréhension et la mémorisation de phrases chez des sujets jeunes, âgés et présentant une Démence de Type Alzheimer (DTA). Les trois groupes de sujets (N = 48) lisaient des paires d'énoncés reliés ou non par un connecteur en Auto-Présentation Segmentée. Ils ont effectué ensuite différentes épreuves: reconnaissance de verbe, questions de compréhension, questions inférentielles et une épreuve de complétion. Les résultats montrent que si la présence d'un connecteur, quel qu'il soit, a peu d'effet sur les performances des sujets jeunes et âgés sains, elle a par contre un impact important sur celles des sujets DTA: le connecteur semble être chez les sujets DTA un indice pour le travail d'intégration interpropositionnelle. En outre, le traitement du connecteur adversatif semble leur poser plus de problèmes que le traitement d'un connecteur causal et additif. The goal of this study is to examine the impact of various connectives such as causal, adversative, additive on sentence comprehension and memory for young, elderly and for subjects suffering from Alzheimer's disease (AD). The three groups (N = 48) read pairs of clauses linked or not by a connective at their own rhythm and they performed different tests: verb recognition, comprehension and inferential questions and completion. Results show that whatever the type of connective, its presence has few effects on young and elderly performances. We note an increase of connectives reading times for AD subjects, suggesting that the presence of connectives seems to be a cue for interclausal integration. Moreover, the treatment of the adversative is more difficult for them than the treatment of causal and additive.

The impact of connectives and anaphoric expressions on expository discourse comprehension

This study focuses on the impact of linguistic markers of coherence on the comprehension of expository discourse. The impact of such markers on comprehension (i.e., off-line) is a highly controversial topic in current studies, especially for connectives for which a facilitating as well as an interfering role has been demonstrated. As a matter of fact, it seems that connectives facilitate the comprehension process in that they improve the reading process, but that they do not increase comprehension of the text. It might even be possible that they ease the reading task in such a way that they provide the reader with the 'impression' of having understood the text instead of a real understanding. The objective of the experiment was to test this far-reaching hypothesis for the use of connectives in expository texts. We wanted to determine the impact of causal connectives such as because ('parce que') and so ('donc') on comprehension and on the feeling of understanding, contrasting it with the impact of anaphoric expressions. Contrary to previous results, our experiment shows that the presence of connectives actually improved comprehension while it did not have an impact on the perception of understanding.

On optimality conditions in optimization problems on solutions of operator equations

We study optimization problems in the presence of connection in the form of operator equations defined in Banach spaces. We prove necessary conditions for optimality of first and second order, for example generalizing the Pontryagin maximal principle for these problems. It is not our purpose to state the most general necessary optimality conditions or to compile a list of all necessary conditions that characterize optimal control in any particular minimization problem. In the present article we describe schemes for obtaining necessary conditions for optimality on solutions of general operator equations defined in Banach spaces, and the scheme discussed here does not require that there be no global functional constraints on the controlling parameters. As an example, in a particular Banach space we prove an optimality condition using the Pontryagin-McShane variation. Bibliography: 20 titles.

Structure of Scientific Knowledge and Curriculum Design

In the theory of teaching, the problem of interrelation between two types of cognition — the scientific and the educational — has been discussed for a long time. The author of this paper has come to the conclusion that logic of an educational subject does not unambiguously follow from the logic of science (paradigm). The same content of the course can be realized with the help of several isomorphous structures of equal value and consistent with the existing logic of science. The choice of structure is determined by educational aims, types of education institutions, periods of studies, the presence of connections between subjects and other conditions.

Ultrastructure of vegetative organization and cell division in Glaucosphaera vacuolata Korshikov (Porphyridiales, Rhodophyta)

Abstract The ultrastructure of vegetative cells and cell division has been examined in Glaucosphaera vacuolala Korshikov. Features either not found or not denoted before include apparent intercisternal fusions within each Golgi body and fibrillar tracts possibly utilized by Golgi vesicles. Mitosis is closed except for large polar gaps and a spherical, presumptive MTOC (microtubule organizing centre) is present at prophase. The MTOC flattens by metaphase to fill the polar gap, becoming the focus of spindle microtubules. No NAO (nucleus associated organelle) was observed. All aspects of mitosis except the absence of an NAO are consistent with mitosis in red algae; most are not consistent with members of the Glaucophyta. Characteristics of mitosis and vegetative features, both those newly observed and those confirmed (especially the presence of connections between chloroplast lobes), support the removal of G. vacuolala from the Glaucophyta and its placement in the Rhodophyta. Also noted in this investigation...

Selective disruption of energy flow from phycobilisomes to Photosystem I

Efficient production of ATP and NADPH by the 'light' reactions of oxygen-evolving photosynthesis demands continuous adjustment of transfer of absorbed light energy from antenna complexes to Photosystem I (PS I) and II (PS II) reaction center complexes in response to changes in light quality. Treatment of intact cyanobacterial cells with N-ethylmaleimide appears to disrupt energy transfer from phycobilisomes to Photosystem I (PS I). Energy transfer from phycobilisomes to Photosystem II (PS II) is unperturbed. Spectroscopic analysis indicates that the individual complexes (phycobilisomes, PS II, PS I) remain functionally intact under these conditions. The results are consistent with the presence of connections between phycobiliproteins and both PS II and PS I, but they do not support the existence of direct contacts between the two photosystems.

Role of the basal ganglia in the reproduction of instrumental reactions developed in response to electrostimulation of the hippocampus

A defensive instrumental conditioned reflex (CR) successively to light flashes and to electrostimulation of the dorsal hippocampus (DH) and the caudate nucleus (CN) was developed in dogs with electrodes implanted in the brain. The contralateral of the DH, CN, the accumbent nucleus (AN) and the globus pallidus (GP) were tested for reproducibility of the instrumental movement. In a second series, the percent of evoked movements was compared with the EP arising in response to signal and test stimulation. The degree of participation of the tested structures in the motivational, signal, and executive components of the CR was elucidated. In the first series the movements were practically not reproduced. In the second series, in the presence of connections from the signal to the tested structures, they were elicited only by stimulation of the AN (15%). In the same series, given bilateral connections, movements in response to the stimulation of the basal ganglia occurred somewhat more frequently (up to 28%). The stimulation of the contralateral DH elicited movements in 75-100% of cases. When stimulation of the CN became a signal, the stimulation of the AN and the GP was accompanied in 40-100% of cases by movement. Thus, the AN participates to a minimal degree in the executive component of the CR. Participation of the basal ganglia in the signal component of the CR was greatest in the third series, which indicates that intrasystemic generalization is more effective than intersystemic.

Determination of connections between cellular structures using 3-d reconstruction from multiple-view stereopair images of thick sections

An important application for serial section reconstruction is determining whether a structure is composed of separate parts, or is continuous. Structures which are apparently separate on random sections may actually be continuous within the 3-D volume. The presence of connections between different types of organelle compartments within a cell should give important information about metabolic control of the cell. The determination of whether an organelle type is composed of multiple compartments, or actually exists as one or a few complexes, should also be of metabolic significance. The metabolic importance of some connections, such as gap junctions, between adjacent cells has already been well established.One method to prove that two membrane-bound structures connect is to trace the membrane continuously from one structure to the other. This is difficult when using thick sections because the membranes may be nearly invisible if they are at an oblique angle to the direction of view.

The effects of periaqueductal gray and nucleus raphe magnus stimulation on the spontaneous and noxious-evoked activity of lateral reticular nucleus neurons in rabbits

In urethane-anesthetized rabbits the effects of periaqueductal gray (PAG) and nucleus raphe magnus (NRM) stimulation on the spontaneous and the noxious-evoked activity of the lateral reticular nucleus (LRN) neurons were studied. The PAG and the NRM stimulating electrodes were located in the optimal sites for suppressing the jaw-opening reflex (JOR) evoked by the tooth pulp stimulation. It was found that the 12% of neurons tested were affected by one or both stmuli. A total of 80 responsive neurons (52% antidromically activated by the cerebellum) were analyzed. Out of these neurons, 31 showed a convergence to both stimuli, 43 responded only to PAG and 6 only to NRM. Noxious heat stimulation of the contralateral foot was effective in altering the activity of 60% of these neurons. The PAG and NRM stimuli modified the noxious-evoked responses in most of these units. While the excitation was the predominant effect on the spontaneous activity (52 cells), the inhibition was predominant on the noxious-evoked activity (29 cells). These results indicate the presence of connections from PAG and NRM to LRN, probably devoted to the processing of the nociceptive information.

Connections between the sensory retina and the retinal pigment epithelium.

The study reports on the presence of connections between the visual receptor outer segments and the apical villi on the retinal pigment epithelium in the human eye. The mechanisms underlying sensory retinal adhesion to the pigment epithelium, recognition and attachment of visual receptor outer segments to the pigment epithelium during phagocytosis, and communication and transport of substances between the two layers of retina have been difficult to define, and molecular connections between the two layers of retina could play an important role in these processes.

Presence of connections between follicles in juvenile mouse ovaries.

AbstractOvaries of 1 to 12 day‐old mice contain multilaminar follicles connected by tubular formations of granulosal cells. Conjoined follicles appear to be at synchronized stages of maturation. It is probable that the development of these interfollicular connections, which form during fetal stages of ovarian morphogenesis, is related to the presence of intercellular bridges between primordial germ cells.