Brain-wide representations of behavior spanning multiple timescales and states in C. elegans.

Changes in an animal's behavior and internal state are accompanied by widespread changes in activity across its brain. However, how neurons across the brain encode behavior and how this is impacted by state is poorly understood. We recorded brain-wide activity and the diverse motor programs of freely moving C. elegans and built probabilistic models that explain how each neuron encodes quantitative behavioral features. By determining the identities of the recorded neurons, we created an atlas of how the defined neuron classes in the C. elegans connectome encode behavior. Many neuron classes have conjunctive representations of multiple behaviors. Moreover, although many neurons encode current motor actions, others integrate recent actions. Changes in behavioral state are accompanied by widespread changes in how neurons encode behavior, and we identify these flexible nodes in the connectome. Our results provide a global map of how the cell types across an animal's brain encode its behavior

Comparison of biofilms morphology for two strains of marine sulfate-reducing bacteria using atomic force microscopy

AISI 304 stainless steel coupons were immersed in VMNI medium containing two strains of Sulfate-reducing bacteria which were isolated from Port Dickson, Negeri Sembilan. The immersion period were set for twenty-four hour, seven days, nine days and fifteen days. At the end of each period, the biofilm were formed on the surface will be maps using Atomic Force Microscopy. The image were taken using contact mode in the 70 μm x 70 μm and 10 μm x 10 μm resolution. Bacteria counts were done using the dilution and plate count technique. Image showed that SRB2 contain more bacteria cell attached to the metal surface by the 7th day of immersion compare to SRB1. But SRB1 produce more condensed and slime like biofilm with some crystallization precipitation while SRB2 bacteria cell were loosely attached. SRB1 bacteria cell were engulf in the slime like matrix while SRB2 bacteria cell is densely packed together. SRB2 showed a slightly higher rate growth in the medium compared to SRB1 but produce low amount of biofilm matrix while SRB1 produce a lot of bio-matrix precipitation and slime formation

Electrochemical impedance spectroscopy studies of stainless steel corrosion by two strains marine sulfate reducing bacteria

This research was conducted to compare corrosion potential of two strains of marine sulfate reducing bacteria (SRB1 and SRB2) on their effect of biocorrosion on stainless steel AISI304 using electrochemical techniques. This study was carried out using Electrochemical Impedance Spectroscopy (EIS) to determine the impedance value (passivity, Rp) and corrosion rate. An electrochemical measurement showed that the value of Impedance for Stainless steel in SRB culture is much smaller compare to VMNI medium (control), indicating a degradation of metal was occurred. SRB2 showed more aggressiveness on corrosion compare to SRB1 as the impedance value, Rp of stainless steel in SRB2 culture is lower compare to SRB1. In conclusion, EIS techniques given a good results to study mechanisms of corrosion and surface passivity

The company and blockchain technology

Blockchain and distributed ledger technology (DLT) have generated much excitement over the past decade, with proclamations that they would disrupt everything from elections to finance. Unsurprisingly, the much-maligned corporate form is also considered ripe for disruption. While certainly imperfect, and currently serviced by creaking legal infrastructure premised upon direct shareholdings, are its problems ones of centralization/intermediation? What exactly are the limits of DLT? In this chapter, we propose to expose the ignorance behind the hype that the venerable corporation will either be revitalized by DLT or replaced by Decentralized Autonomous Organizations (DAOs). We will demonstrate that proponents of DLT disruption either overestimate the potential of the technology by taking at face value its claims of security without unpacking what said security entails (and what it does not) or lack awareness of the history of and market demand for intermediation as well as the complexities of modern corporations

Modelling of LHW-induced helical current filaments on EAST: study of an alternative method of applying RMPs

The lower hybrid wave (LHW) heating experiments at the Experimental Advanced Superconducting Tokamak (EAST) show a wide range of similarities to effects known from applied resonant magnetic perturbations (RMPs) by in-vessel or external magnetic perturbation coils. These observations suggest a current flow understood to be along scrape-off layer (SOL) field lines; here called helical current filaments (HCFs). For a better understanding of the experimental observations, a model to incorporate the magnetic perturbation of HCFs in the magnetic topology has been developed. Modelled SOL field lines, starting in front of the LHW antenna, show agreement in position and pitch-angle with the experimentally observed radiation belts. The comparison of the pick-up coil signals and the modelled HCFs' perturbation allows for determination of the current strength depending on the filaments' distance from the plasma edge. Agreement of predicted footprint structures with experimentally observed heat load and particle flux profiles at different toroidal angles in the divertor region is found. Based on the modelling results, the idea of LHW-induced RMPs, originating from the experimental observations, is strongly supported

Recent progress of RF-dominated experiments on EAST

The research of EAST program is mostly focused on the development of high performance steady state scenario with ITER-like poloidal configuration and RF-dominated heating schemes. With the enhanced ITER-relevant auxiliary heating and current drive systems, the plasma profile control by coupling/integration of various combinations has been investigated, including lower hybrid current drive (LHCD), electron cyclotron resonance heating (ECRH) and ion cyclotron resonance heating (ICRH). The 12 MW ICRH system has been installed on EAST. Heating and confinement studies using the Hydrogen Minority Heating scheme have been investigated. One of the importance challenges for EAST is coupling higher power into the core plasma, experiments including changing plasma position, electron density, local gas puffing and antenna phasing scanning were performed to improve ICRF coupling efficiency on EAST. Results show that local gas injection and reducing the k|| can improve the coupling efficiency directly. By means of the 4.6 GHz and 2.45 GHz LHCD systems, H-mode can be obtained and sustained at relatively high density, even up to ne ∼ 4.5 × 1019 m-3, where a current drive effect is still observed. Meanwhile, effect of source frequency (2.45GHz and 4.6GHz) on LHCD characteristic has been studied on EAST, showing that higher frequency improves penetration of the coupled LH (lower hybrid) power into the plasma core and leads to a better effect on plasma characteristics. Studies demonstrate the role of parasitic effects of edge plasma in LHCD and the mitigation by increasing source frequency. Experiments of effect of LH spectrum and plasma density on plasma characteristics are performed, suggesting the possibility of plasma control for high performance. The development of a 4MW ECRH system is in progress for the purpose of plasma heating and MHD control. The built ECRH system with 1MW source power has been successfully put into use on EAST in 2015. H-mode discharges with L-H transition triggered by ECRH injection were obtained and its effects on the electron temperature, particle confinement and the core MHD stabilities were observed. By further exploring and optimizing the RF combination for the sole RF heating and current drive regime, fully non-inductive H-mode discharges with Vloop∼0V has progressed steadily in the 2016 campaign. The overview of the significant progress of RF dominated experiments is presented in this paper

Recent progress of RF-dominated experiments on EAST

The research of EAST program is mostly focused on the development of high performance steady state scenario with ITER-like poloidal configuration and RF-dominated heating schemes. With the enhanced ITER-relevant auxiliary heating and current drive systems, the plasma profile control by coupling/integration of various combinations has been investigated, including lower hybrid current drive (LHCD), electron cyclotron resonance heating (ECRH) and ion cyclotron resonance heating (ICRH). The 12 MW ICRH system has been installed on EAST. Heating and confinement studies using the Hydrogen Minority Heating scheme have been investigated. One of the importance challenges for EAST is coupling higher power into the core plasma, experiments including changing plasma position, electron density, local gas puffing and antenna phasing scanning were performed to improve ICRF coupling efficiency on EAST. Results show that local gas injection and reducing the k|| can improve the coupling efficiency directly. By means of the 4.6 GHz and 2.45 GHz LHCD systems, H-mode can be obtained and sustained at relatively high density, even up to ne ∼ 4.5 × 1019 m-3, where a current drive effect is still observed. Meanwhile, effect of source frequency (2.45GHz and 4.6GHz) on LHCD characteristic has been studied on EAST, showing that higher frequency improves penetration of the coupled LH (lower hybrid) power into the plasma core and leads to a better effect on plasma characteristics. Studies demonstrate the role of parasitic effects of edge plasma in LHCD and the mitigation by increasing source frequency. Experiments of effect of LH spectrum and plasma density on plasma characteristics are performed, suggesting the possibility of plasma control for high performance. The development of a 4MW ECRH system is in progress for the purpose of plasma heating and MHD control. The built ECRH system with 1MW source power has been successfully put into use on EAST in 2015. H-mode discharges with L-H transition triggered by ECRH injection were obtained and its effects on the electron temperature, particle confinement and the core MHD stabilities were observed. By further exploring and optimizing the RF combination for the sole RF heating and current drive regime, fully non-inductive H-mode discharges with Vloop∼0V has progressed steadily in the 2016 campaign. The overview of the significant progress of RF dominated experiments is presented in this paper