Ferroelectric and dielectric characterization studies on relaxor- and ferroelectric-like strontium-barium niobates

Ferroelectric domain structure evolution induced by an external electric field was investigated by means of nematic liquid crystal (NLC) method in two strontium-barium niobate single crystals of nominal composition: Sr_{0.70}Ba_{0.30}Nb_{2}O_{6} (SBN:70 - relaxor) and Sr_{0.26}Ba_{0.74}Nb_{2}O_{6} (SBN:26 - ferroelectric). Our results provide evidence that the broad phase transition and frequency dispersion that are exhibited in SBN:70 crystal have a strong link to the configuration of ferroelectric microdomains. The large leakage current revealed in SBN:26 may compensate internal charges acting as pinning centers for domain walls, which gives rise to a less restricted domain growth similar to that observed in classical ferroelectrics. Microscale studies of a switching process in conjunction with electrical measurements allowed us to establish a relationship between local properties of the domain dynamics and macroscopic response i.e., polarization hysteresis loop and dielectric properties.Comment: 10 pages, 7 figure

Analisis Perbedaan Abnormal Return dan Trading Volume Activity Sebelum Sesudah Stock Split pada Perusahaan Go Public yang Terdaftar di BEI Periode 2012-2015

Stock split adalah salah satu aksi korporasi yang dilakukan perusahaan untuk menghasilkan informasi yang efisien. Namun, penelitian ini menunjukkan bahwa stock split memiliki dampak pada perusahaan. Penelitian ini bertujuan untuk menganalisis perbedaan abnormal return dan trading volume activity 7 hari sebelum dan 7 hari sesudah pengumuman stock split. Populasi dari penelitian ini adalah perusahaan yang terdaftar di Bursa Efek Indonesia (BEI) 2012-2015. Sampel penelitian ini mencakup 40 perusahaan dengan menggunakan metode purposive sampling. Penelitian ini menggunakan data sekunder. Teknik analisis data yang digunakan adalah uji normalitas dan wilcoxon signed rank test. Hasil penelitian menunjukkan bahwa terdapat perbedaan abnormal return sebelum dan sesudah stock split dan tidak terdapat perbedaan trading volume activity sebelum dan sesudah stock split

Sejarah Komuniti Buruh Estet Cina Di Borneo Utara 1881-1942

Penulisan awal mengenai komuniti Cina di Borneo Utara semasa pemerintahan Syarikat Berpiagam Borneo Utara British (1881-1942) lebih menumpukan kepada persoalan klise seperti migrasi komuniti Cina ke Borneo Utara, kawasan penempatan awal komuniti Cina di Borneo Utara, dan sumbangan komuniti Cina ke atas ekonomi di Borneo Utara. Penulisan mengenai suasana kerja buruh-buruh Cina di estet Borneo Utara sering dipinggirkan meskipun terdapat penulisan seperti yang dihasilkan oleh Danny Wong Tze Ken yang mengetengahkan isu buruh-buruh Cina di Borneo Utara. Walau bagaimana pun, isu perburuhan yang diketengahkan lebih menjurus kepada persoalan kehidupan komuniti buruh Cina dari sudut pandangan golongan buruh. Meskipun buruh-buruh Cina yang bekerja di estet tembakau di Borneo Utara bekerja secara kontrak, namun terdapat laporan yang menyatakan berlaku penindasan ke atas mereka yang didalangi oleh pihak majikan. Penulisan ini unik kerana menyediakan dimensi lain dalam sejarah komuniti buruh Cina di estet tembakau Borneo Utara iaitu memberi penjelasan akan suasana kerja dan layanan majikan terhadap buruh Cina di estet tembakau dari sudut pandangan pihak majikan mahupun pemodal dan dari sudut pandangan komuniti buruh. Begitu pun, diharapkan agar penulisan ini akan menggalakkan penyelidikan lanjut berkenaan sejarah Sabah di masa hadapan

Decreasing groundwater quality at Cisadane riverbanks: groundwater-surface water approach

The decreasing of groundwater quality has been the major issue in Tangerang area. One of the key process is the interaction between groundwater and Cisadane river water, which flows over volcanic deposits of Bojongmanik Fm, Genteng Fm, Tuf Banten, and Alluvial Fan. The objective of this study is to unravel such interactions based on the potentiometric mapping in the riverbank. We had 60 stop sites along the riverbank for groundwater and river water level observations, and chemical measurements (TDS, EC, temp, and pH). Three river water gauge were also analyzed to see the fluctuations. We identified three types of hydrodynamic relationships with fairly low flow gradients: effluent flow at Segmen I (Kranggan - Batuceper) with 0.2-0.25 gradient, perched flow at Segmen II (Batuceper-Kalibaru) with gradient 0.2-0.25, and influent flow at Segmen III (Kalibaru-Tanjungburung) with gradient 0.15-0.20. Such low flow gradient is controlled by the moderate to low morphological slope in the area. The gaining and losing stream model were also supported by the river water fluctuation data. TDS and EC readings increased more than 40$\%$ from upstream to downstream. At some points the both measurements were two times higher than the permissible limits, along with the drops of pH values at those areas. This study shows the very close interaction between Cisadane river water and groundwater in the riverbank. Therefore the authorities need to be managed the areas with a very strict regulations related to the small and large scale industries located near by the river.Comment: 8 pages, 6 figures, have been presented in Asian Physics Symposium in Indonesia 2015 and will be published in IOP Conference Serie

Spatial Decision Assistance of Watershed Sedimentation (SDAS): Development and Application

This paper discusses the development and application of a spatial tool for erosion modeling named Spatial Decision Assistance of Watershed Sedimentation (SDAS). SDAS computes export (yield) of sediment from watershed as product of erosion rate and sediment delivery ratio (SDR). The erosion rate is calculated for each raster grid according to a digital elevation model, soil, rain fall depth, and land cover data using the Universal Soil Loss Equation. SDR calculation is carried out for each spatial unit. A spatial unit is the smallest sub-watershed considered in the model and generated according to the TauDEM algorithm. The size of one spatial unit is assigned by the user as the minimum number of raster grids. SDR is inversely proportional to sediment resident time and controlled by rainfall, slope, soil, and land cover. Application of SDAS is demonstrated in this paper by simulating the spatial distribution of the annual sediment yield across the Citarum watershed in the northwest of Java, Indonesia. SDAS calibration was carried out based on sediment discharge observations from the upper catchment. We considered factors for hillslope flow depth and for actual and effective rainfall duration to fit the computed sediment yield to the observed sediment discharge. The computed sediment yield agreed with the observation data with a 7% mean relative accuracy

Biomechanical Simulation of Electrode Migration for Deep Brain Stimulation

International audienceDeep Brain Stimulation is a modern surgical technique for treating patients who suffer from affective or motion disorders such as Parkinson's disease. The efficiency of the procedure relies heavily on the accuracy of the placement of a micro-electrode which sends electrical pulses to a specific part of the brain that controls motion and affective symptoms. However, targeting this small anatomical structure is rendered difficult due to a series of brain shifts that take place during and after the procedure. This paper introduces a biomechanical simulation of the intra and postoperative stages of the procedure in order to determine lead deformation and electrode migration due to brain shift. To achieve this goal, we propose a global approach, which accounts for brain deformation but also for the numerous interactions that take place during the procedure (contacts between the brain and the inner part of the skull and falx cerebri, effect of the cerebro-spinal fluid, and biomechanical interactions between the brain and the electrodes and cannula used during the procedure). Preliminary results show a good correlation between our simulations and various results reported in the literature

Comprehensive Approaches to the Treatment of Esophageal Achalasia: A Review of Current Methods

Introduction and purpose Achalasia is the most prevalent primary esophageal motility disorder, marked by improper relaxation of the lower esophageal sphincter (LES), increased resting pressure in the LES, and a lack of peristalsis in the esophagus. Symptoms include difficulty swallowing (dysphagia), regurgitation, chest pain, and weight loss. Due to the nonspecific nature of these symptoms, diagnosis can be delayed by several years. Since the underlying cause of achalasia is still unknown, treatment options focus on alleviating symptoms by targeting the lower esophageal sphincter. Materials and methods    This paper is based on a literature review sourced from PubMed, using the following keywords: achalasia, POEM, laparoscopic cardiomyotomy, pneumatic dilation, and botulinum toxin injection. Results Various treatment options are available for achalasia, each offering unique features and results. The main approaches include Peroral Endoscopic Myotomy (POEM), Laparoscopic Myotomy (LM), Botulinum Toxin Injection, and Pneumatic Dilation (PD). Conclusion Each treatment differs in its level of invasiveness, duration of symptom relief, risk of complications, and the likelihood of requiring additional interventions. The selection of the most suitable option is influenced by individual patient factors, such as the type and severity of achalasia, overall health, and personal preferenc