An investigation into aripiprazole's partial D(2) agonist effects within the dorsolateral prefrontal cortex during working memory in healthy volunteers

Rationale: Working memory impairments in schizophrenia have been attributed to dysfunction of the dorsolateral prefrontal cortex (DLPFC) which in turn may be due to low DLPFC dopamine innervation. Conventional antipsychotic drugs block DLPFC D2 receptors, and this may lead to further dysfunction and working memory impairments. Aripiprazole is a D2 receptor partial agonist hypothesised to enhance PFC dopamine functioning, possibly improving working memory. Objectives: We probed the implications of the partial D2 receptor agonist actions of aripiprazole within the DLPFC during working memory. Investigations were carried out in healthy volunteers to eliminate confounds of illness or medication status. Aripiprazole’s prefrontal actions were compared with the D2/5-HT2A blocker risperidone to separate aripiprazole’s unique prefrontal D2 agonist actions from its serotinergic and striatal D2 actions that it shares with risperidone. Method: A double-blind, placebo-controlled, parallel design was implemented. Participants received a single dose of either 5 mg aripiprazole, 1 mg risperidone or placebo before performing the n-back task whilst undergoing fMRI scanning. Results: Compared with placebo, the aripiprazole group demonstrated enhanced DLPFC activation associated with a trend for improved discriminability (d’) and speeded reaction times. In contrast to aripiprazole’s neural effects, the risperidone group demonstrated a trend for reduced DLPFC recruitment. Unexpectedly, the risperidone group demonstrated similar effects to aripiprazole on d’ and additionally had reduced errors of commission compared with placebo. Conclusion: Aripiprazole has unique DLPFC actions attributed to its prefrontal D2 agonist action. Risperidone’s serotinergic action that results in prefrontal dopamine release may have protected against any impairing effects of its prefrontal D2 blockade

FAKTOR-FAKTOR YANG BERHUBUNGAN DENGAN OBESITAS SENTRAL PADA MAHASISWA LAKI-LAKI FAKULTAS TEKNIK UNIVERSITAS DIPONEGORO

Obesitas merupakan salah satu masalah kesehatan yang banyak terjadi di zaman modern ini. Salah satu jenis obesitas yang berbahaya bagi kesehatan adalah obesitas sentral. Obesitas sentral adalah penumpukan lemak dalam tubuh bagian perut dan salah satu penyebab terjadinya penyakit-penyakit degeneratif. Tujuan dari penelitian ini adalah untuk mengetahui faktor-faktor yang berhubungan dengan obesitas sentral pada mahasiswa laki-laki. Penelitian ini menggunakan jenis penelitian observasional dengan desain cross sectional yang dilakukan di Fakultas Teknik Universitas Diponegoro. Populasi dalam penelitian ini adalah mahasiswa laki-laki Fakultas Teknik Universitas Diponegoro kemudian diambil sampel sebanyak 100 orang. Teknik pengambilan sampel dengan consecutive sampling. Dilakukan pengukuran lingkar perut, antropometri, tekanan darah, kolesterol total dan pengisian kuesioner aktivitas fisik PAL, asupan food recall dan FFQ. Analisis data menggunakan uji korelasi Pearson Product Moment dan Rank Spearman. Dari 100 responden penelitian didapatkan 44% responden obesitas sentral. Tidak ada hubungan antara aktivitas fisik, asupan energi, karbohidrat, protein, lemak, serat, frekuensi konsumsi fast food, dan frekuensi sarapan dengan kejadian obesitas sentral. Terdapat hubungan antara obesitas sentral dengan indeks massa tubuh (p=0,0001), persen lemak tubuh (p=0,0001), tekanan darah sistolik (p=0,0001), tekanan darah diastolik (p=0,0001), dan kolesterol total (p=0,0001). Saran yang diberikan bagi mahasiswa adalah agar dapat menjaga pola makan dengan tidak mengkonsumsi makanan berlemak dan meningkatkan aktivitas fisik dengan berolahraga secara teratur. Kata Kunci: obesitas sentral, obesitas, pola maka

Multiresolution active contour models in textured stereo images

This paper presents a method for generating sparse range data from textured surfaces which have structured light projected onto them. The work is motivated by the need to measure 3-D road defects rapidly and reliably. Traditional approaches to computing range from stereoscopic images have replied on either smooth or finely textured surfaces when using structured light. Conventional techniques that take advantage of the inherent texture in the images are not applicable. This is because corresponding stereoscopic road surface views are dissimilar due to the geometry of the cameras and the surface texture. The method described places initial edge points in a low resolution version of the intensity image. These points are used to initialise open active contour models or snakes which are propagated via a pyramid to a higher resolution. At this higher resolution, internal and external constraints are applied to the snake; the internal constraint being a smoothness functional and the external one being based on a maximum likelihood estimate of the edge strength across each light stripe. Computation is spatially localised at each stage and thus this algorithm could easily be parallelised. 1

Contract-Linda: A Paradigm for Programming Heterogeneous Parallel Systems

Contract-Linda is a novel programming architecture for heterogeneous parallel machines particularly suited to image processing. Previous research has concentrated on static and pre-determined scheduling of computation and on fine grain parallelism. Pre-determined scheduling is satisfactory in cases where the computational process is fully deterministic. However with many image interpretation schemes the flow of control and the nature of the computational procedures can only be determined at run-time. In this paper we describe a programming paradigm for coarse grain and task level parallelism. Task management is based on the Contract Net protocol and utilises the Linda Coordination Language to provide run-time scheduling. This paradigm accommodates a closely coupled network of heterogeneous processing modules which differ greatly in computational capability; modules based on neural networks, semantic networks, vector and scalar processors are accommodated. Contract-Linda allows speciali..