TEORI PERKEMBANGAN KOGNITIF JEAN PIAGET DAN PROBLEMATIKANYA PADA ANAK USIA SEKOLAH DASAR

Cognitive development is a change processes of human life in understanding, managing information, solving problems and knowing something. Jean Piaget is one of a figures studied cognitive development and said about cognitive development steps. Jean Piaget is also a biologist who links the physical maturity development with cognitive development steps. These steps are the motoric sensory step (0–2 years), pre-operational (2-7 years), concrete operations (7–11 years) and formal operations (11–15 years). In understanding the world actively, a child uses a scheme, assimilation, accommodation, organization and equilibration. A child's knowledge formed gradually in line with the information experience found. According to Piaget, children undergo a definite sequence of cognitive development steps. In this theory, children predicted to have maturity quantity and quality based on the steps passed. a step of cognitive development is a continuation of previous cognitive development. Cognitive problems arise in elementary school children viewed from Piaget's cognitive development theory including dyslexia, dysgraphia and dyscalculia. Perkembangan kognitif adalah tahapan-tahapan perubahan yang terjadi dalam rentang kehidupan manusia untuk memahami, mengolah informasi, memecahkan masalah dan mengetahui sesuatu. Jean Piaget adalah salah satu tokoh yang meneliti tentang perkembangan kognitif dan mengemukakan tahapan-tahapan perkembangan kognitif. Jean Piaget yang juga ahli Biologi menghubungkan tahapan perkembangan kematangan fisik dengan tahapan perkembangan kognitif. Tahapan-tahapan tersebut adalah tahap sensory motorik (0–2 tahun), pra-operasional (2–7 tahun), operasional konkret (7–11 tahun) dan operasional formal (11–15 tahun). Dalam memahami dunia secara aktif, anak menggunakan skema, asimilasi, akomodasi, organisasi dan equilibrasi. Pengetahuan anak terbentuk secara berangsur sejalan dengan pengalaman tentang informasi-informasi yang ditemui. Menurut Piaget, anak menjalani urutan yang sudah pasti dari tahap-tahap perkembangan kognitif. Pada teori ini, anak diprediksi memiliki kematangan secara kuantitas maupun kualitas berdasarkan tahapan-tahapan yang dilaluinya. Perkembangan kognitif pada satu tahap merupakan lanjutan dari perkembangan kognitif tahap sebelumnya. Problem kognitif yang muncul pada anak usia sekolah dasar dilihat dari teori perkembangan kognitif ala Piaget diantaranya disleksia, disgrafia dan diskalkulia.

To the question about the interpretation of saxophone compositions by V. Runchak (performing aspect)

The purpose of this represented article is denoting the mostcharacteristic, artistically content interpretations of saxophonecompositions by V. Runchak into the light of performing technologycriterions for possess playing art on wind academy instruments. The targetof this publication is also multisided population of masterpieces forsaxophone by V. Runchak from point of view their performing activationinto concert-festival, pedagogical, competitive and cultural-enlighteningfunctional spheres. The round of methods for this investigation isconcentrated, primarily, in applying of performing analysis method, whichallows designating of the maximally characteristic traits for artisticallyimaginative pallet of works for saxophone by V. Runchak into aspect theirtechnical, performing actively comprehension. The structurally analyticalmethod purchases the ponderable significance. It makes the possibility tobuild definite sequence of representation as touching scientificallyinvestigative material. The appeal to the axiological method is stipulatingby rushing to determination the most artistically value, performinginteresting of the saxophone compositions by V. Runchak. Scientificnewness of this article is achieving the statement from facts of incrediblyseldom the appealing to the questions of interpretive for compositions byV. Runchak, which were written by well-known composer for windacademic instruments a namely saxophone. The research novelty of theproposed work is also focusing into synthetic representation of the series artistically imaginative characters concerning saxophones’ compositionswith their performing-technologic peculiarity. Conclusions. Thesaxophones’ masterpieces by V. Runchak is not only artisticallyextravagant, to a certain extent shocking from technic their compositionalwriting, performing technological particularity as touching possession ofsaxophone but to a specific measure they are amazingly experimental andhighly intellectual musical academic compositions.

High order iterative learning control to solve the trajectory tracking problem for robot manipulators using Lyapunov theory

This paper deals with Iterative Learning Control (ILC) design to solve the trajectory tracking problem for rigid robot manipulators subject to external disturbances, and performing repetitive tasks. A high order ILC scheme is synthetized; this controller contains the information (errors) of several iterations and not only of one iteration. It has been shown that the closed loop system (robot plus controller) is asymptotically stable, over the whole finite time interval, when the iteration number tends to infinity. This proof is based upon the use of a Lyapunov-like positive definite sequence, which is shown to be monotonically decreasing under the proposed controller scheme. Finally, simulation results on two-link manipulator are provided to illustrate the effectiveness of the proposed controller.

INTUITIONISTIC ANALYSIS AT THE END OF TIME

Kripke recently suggested viewing the intuitionistic continuum as an expansion in time of a definite classical continuum. We prove the classical consistency of a three-sorted intuitionistic formal system IC, simultaneously extending Kleene’s intuitionistic analysis I and a negative copy C° of the classically correct part of I, with an “end of time” axiom ET asserting that no choice sequence can be guaranteed not to be pointwise equal to a definite (classical or lawlike) sequence. “Not every sequence is pointwise equal to a definite sequence” is independent of IC. The proofs are by Crealizability interpretations based on classical ω-models ${\cal M}$ = $\left( {\omega ,{\cal C}} \right)$ of C°.

ANGULAR INTRICACIES IN HOT GAUGE FIELD THEORIES

In hot quantum field theories, "Hard Thermal Loops" leading order calculations call for a definite sequence of angular averages and discontinuity (or Imaginary part prescription) operations, and run otherwise into incorrect results. The ten years old collinear singularity problem of hot QCD, provides a dramatic illustration of that fate.

Chirality in the RNA world and beyond

Homochirality is an essential feature of biology, but how it developed in early life remains unclear. Our aim in this paper is to add to the discussion by taking a somewhat arbitrary but definite sequence of events and examining carefully the chirality at each stage. Our scenario for the development of life starts with the prebiotic, continues through a pre-RNA stage to the RNA world. This leads to the development of proteins and then to the incorporation of DNA in RNA–DNA–protein biochemistry.We argue that homochirality probably did not develop prebiotically. We see the likely chiral bifurcation point to be during the development of RNA from an achiral pre-RNA. Surprisingly, we find the driving force for this to be enantiomeric cross-inhibition in which the addition of a ‘wrong-handed’ enantiomer to a growing polymer brings the polymerization to a halt. This, it is often argued, is a serious impediment to the development of chiral purity. We suggest that the sign of handedness at this stage was probably determined by chance. We then point out that homochiral RNA was unlikely by itself to lead to homochiral proteins. We identify the additional nonlinear feature required for bifurcation to be the rapid increase in enzymic power available when the amino acids in proteins approach single handedness and structural features such as α-helices and β-sheets become viable. If this is correct, then the handedness of the protein sector is indeed linked to that of RNA. However, the relative sign of the two handednesses will have depended on the precise stereo-sensitive interaction between the RNA and protein systems. We suggest that the most plausible scenario is via the recently discovered RNA binding sites for amino acids, which are both stereo-selective and have contact with the developing genetic code. The detailed steps that determine the handedness are not yet clear and may be specific to the precise development path.It follows that if biochemistry similar to that on Earth developed extraterrestrially, we would surely have homochirality but at this stage we cannot be sure about the handedness of either the nucleic acid or the protein components.

Acetylcholine lengthens action potentials of sheep cardiac Purkinje fibers

The effect of acetylcholine (ACh) on the electrical activity of sheep cardiac Purkinje fibers was studied using standard microelectrode techniques. Most fibers showed a definite sequence of changes when exposed to ACh. Initially, action potential duration (APD) increased markedly. After about 20 s, the maximum diastolic potential (MDP) started to become more negative and, at the same time, the rate of increase in APD slowed. Once the MDP stabilized at a more negative level, the APD usually resumed its rapid increase. ACh also increased the slope of diastolic depolarization and made the plateau voltage more positive. APD was increased by ACh concentrations as low as 10(-7) M, and it increased with concentrations up to 10(-5) M (the highest concentration tested). ACh-induced increases in APD depended on the stimulation frequency; 2-min exposures to 10(-6) M ACh increased APD by 76.8 +/- 14.7% at 6 min-1 and 17.7 +/- 4.2% at 60 min-1. Atropine blocked all the effects of ACh. Hexamethonium did not prevent the ACh effects. It is concluded that ACh acts via muscarinic receptors. The changes in APD and MDP appear to be separate events, and it is difficult to see how the former effect may be explained by known actions of ACh.

Assessment of the negative and positive feedback effects of administered oestrogen on gonadotrophin release in patients with anorexia nervosa

SynopsisThe capacity of the hypothalamic–pituitary axis to respond with changes in LH release to the negative and positive feedback effects of oestrogen was assessed in 19 patients with anorexia nervosa at different stages of the illness. Ethinyl oestradiol, 200 μg daily for 3 days, was administered and serial estimations of serum LH were carried out during and after the course of oestrogen.In patients with anorexia nervosa tested when markedly underweight, negative feedback effects of oestrogen were demonstrated in those patients with detectable levels of LH. None of the patients demonstrated positive feedback release of LH to the oestrogen stimulus.After the resumption of a more normal weight, basal LH levels were higher and negative feedback effects of oestrogen were observed in 11 out of 12 patients. The complete response to oestrogen with a subsequent positive release of LH to the oestrogen stimulus was shown by only 3 patients. Two of these 3 patients maintained a normal weight during the subsequent 6 months and both resumed regular menstruation shortly after the test. Three additional patients who had shown only negative feedback effects of oestrogen on LH release similarly maintained a normal weight and only 1 of them resumed menstruation, starting 3 months after the oestrogen test.It was concluded that in recovery from anorexia nervosa there is a return of normal hypothalamicpituitary–gonadal activity in a definite sequence with recovery of the hypothalamus to respond normally to the negative feedback effects of oestrogen followed by return of the positive feedback capacity between oestrogen and LH which allows menstruation to resume. The resumption of normal hypothalamic–pituitary function is clearly dependent in part upon correction of the malnutrition. However, after correction of the malnutrition some patients fail to menstruate, and this appears to be determined by a continuing impairment of the hypothalamus to respond normally to the feedback effects of oestrogen upon gonadotrophin release.

Positive Definite Sequence of Operators and a Fixed Point Theorem

The purpose of this note is to prove the following:Theorem. Let {An} be a positive definite sequence of operators on a Hilbert space H with A0=1. If A1f=f for some f in H, then Anf=f for all n.Note that a bilateral sequence of operators {An:n = 0, ±1, ±2,…} on H is positive definite iffor every finitely nonzero sequence {fn} of vectors in H [1].