Tracing Recent Star Formation of Red Early-type Galaxies out to zz ∼\sim 1

We study the mid-infrared (IR) excess emission of early-type galaxies (ETGs) on the red-sequence at $z <$ 1 using a spectroscopic sample of galaxies in the fields of Great Observatories Origins Deep Survey (GOODS). In the mass-limited sample of 1025 galaxies with $M_{star}$ $>$ 10$^{10.5}$ $M_{\odot}$ and $0.4<z<1.05$, we identify 696 $Spitzer$ 24 $\mu$m detected (above the 5$\sigma$) galaxies and find them to have a wide range of NUV-$r$ and $r$-[12 $\mu$m] colors despite their red optical $u-r$ colors. Even in the sample of very massive ETGs on the red sequence with $M_{star}$ $>$ 10$^{11.2}$ $M_{\odot}$, more than 18% show excess emission over the photospheric emission in the mid-IR. The combination with the results of red ETGs in the local universe suggests that the recent star formation is not rare among quiescent, red ETGs at least out to $z \sim 1$ if the mid-IR excess emission results from intermediate-age stars or/and from low-level ongoing star formation. Our color$-$color diagram including near-UV and mid-IR emissions are efficient not only for identifying ETGs with recent star formation, but also for distinguishing quiescent galaxies from dusty star-forming galaxies.Comment: 25 pages, 9 figures, accepted for publication in Ap

Effectiveness of a six-week high-intensity interval training programme on cardiometabolic markers in sedentary males

High-intensity interval training (HIT) has been proposed as an effective, time efficient strategy to elicit similar cardiometabolic health benefits as traditional moderate-intensity endurance training. This is an important consideration as "lack of time" is a common cited barrier to regular physical activity

STUDENT ENGAGEMENT IN FIRST YEAR CHEMISTRY – ONLINE VS FACE TO FACE

Rapid campus closure and an unexpected transition to an online offering of a large first year chemistry unit provided an opportunity to explore the level of student engagement and factors associated with success in this online transition. In this presentation, we compare the standard, face-to-face offering in 2019 to the online offering in 2020 by examining the completion of weekly assessment tasks and the uptake of a variety of learning activities. All measures of engagement have been correlated to the students’ final scores in the unit. We found that students were able to quickly adapt to using the technology including accessing live streamed or recorded lectures, joining online tutorials and discussion forum use. Participation in in-class polling was unchanged, and was associated with the same increase in final score. The only learning activity with a significant change was tutorials; face-to-face tutorial attendance gained students 2.7 marks out of 100 in their final score per tutorial, whereas online tutorial attendance only gained 1.8 marks per tutorial. The decrease in completion of the weekly low stakes assessment tasks over the semester was unchanged, but overall quiz scores were slightly higher. Completion of online practical activities was the same in both years. Scores for a video recorded practical activity with drop-in consultation were 0.9/10 lower compared to the identical activity and worksheet conducted face to face. Our data show that some aspects of learning can be moved online seamlessly, but face-to-face practical sessions and tutorials have a greater impact on student success than online versions

A lithium iron phosphate reference electrode for ionic liquid electrolytes

We report on the development of a very simple and robust reference electrode suitable for use in room temperature ionic liquids, that can be employed with planar devices. The reference electrode is based on LiFePO4(LFP), a common cathode material in Li-ion batteries, which is air and water stable. The reference electrode can be drop-cast onto a planar electrode device in a single step. We demonstrate that very low Li+-ion concentrations (millimolar or below) are sufficient to obtain a stable and reproducible LFP potential, thus making physical separation between the reference and working electrode unnecessary. Most importantly, the LFP potential is also entirely stable in the presence of oxygen and shows only a very small drift (&lt;10 mV) in the presence of hydrogen gas, while the potential of a platinum pseudo-reference electrode is shifted &gt;800 mV. This is the first time that such a stable reference electrode system for ionic liquids has been implemented in miniaturized, planar electrode devices

Oxygen reduction voltammetry on platinum macrodisk and screen-printed electrodes in ionic liquids: Reaction of the electrogenerated superoxide species with compounds used in the paste of Pt screen-printed electrodes?

Screen-printed electrodes (SPEs) are widely investigated as simple, three-electrode planar surfaces for electrochemical sensing applications, and may be ideal for gas sensing purposes when combined with non-volatile room temperature ionic liquids (RTILs). In this report the suitability of SPEs with RTIL solvents has been investigated for oxygen detection. Oxygen reduction has been studied on commercially available platinum SPEs in eight RTILs. Cyclic voltammetric wave shapes were found to be significantly different on Pt SPE surfaces compared to conventional solid Pt macroelectrodes, suggesting a possible reaction of the electrogenerated superoxide with the compounds that make up the ink/paste of the SPE surface. The only RTIL that did not show such drastically different voltammetry was one that contained a pyrrolidinium cation, suggesting a more chemically stable solvent environment compared to the other imidazolium and phosphonium cations studied. The analytical utility was then studied on four SPE surfaces (carbon, gold, platinum and silver) in two RTILs (one with a pyrrolidinium and one with an imidazolium cation) and linear responses were observed between current and % concentration in the range 10–100% O2. This suggests that SPEs may indeed be suitable for oxygen sensing in some RTILs, but significantly more pre-treatment of the surface is required to obtain reliable results. However, the reaction of superoxide with the SPE ink, together with a noticeable deterioration of the signal over time, suggests that this type of sensing platform may only be suitable for “single-use” oxygen sensing applications

Analysis and Testing of a Nano-Positioning Stage

The project characterizes the performance of a nano-positioning stage (NPS) designed by the MIT Lincoln Laboratory. The NPS is part of a highly precise beam-steering device used in laser communications. The NPS is comprised of a flexured stage, actuated by Piezo actuators in two degrees of freedom. The project presents the design of testing fixtures and testing procedures to predict performance, strength and dynamic response of the NPS. The results and analyses address the creep, hysteresis, total travel, cross-axis response, and temperature survivability of the NPS. Finite element analysis of the NPS was performed and validated by comparisons with the experiments. Recommendations for future testing and improvements of the current baseline design are presented

Achievement of prolonged oxygen detection in room-temperature ionic liquids on mechanically polished platinum screen-printed electrodes

The demonstration of prolonged amperometric detection of oxygen in room-temperature ionic liquids (RTILs) was achieved by the use of mechanical polishing to activate platinum screen-printed electrodes (Pt-SPEs). The RTILs studied were 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][NTf2]) and N-butyl-N-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide ([C4mpyrr][NTf2]). It was found that voltammetry on polished Pt-SPEs exhibited less deterioration (in terms of voltammogram shapes, stability of peak currents, and appearance of contaminant peaks) from long-term consecutive cycling under 100% vol oxygen flow in both RTILs. The detection capability of these RTIL/Pt-SPE systems, initially subjected to long-term consecutive voltammetric cycling, was also investigated by cyclic voltammetry (CV) and long-term chronoamperometry (LTCA). Current versus concentration plots were linear on both unpolished and polished electrodes for 10-100% vol O2 (using CV) and 0.1-5% vol O2 (using LTCA). However, sensitivities and limits of detection (LODs) from CV were found to improve significantly on polished electrodes compared to unpolished electrodes, particularly in [C2mim][NTf2], but also moderately in [C4mpyrr][NTf2]. The lowest LODs (of ca. 0.1% vol O2) were found on polished SPEs using LTCA, with the most stable responses observed in [C4mpyrr][NTf2]. Calibration graphs could not be obtained on unpolished electrodes in both RTILs using LTCA. The results show that polishing markedly improves the analytical performances of Pt-SPEs for oxygen sensing in RTILs. The reusability of such disposable Pt-SPEs, after the surfaces had been experimentally fouled, was also demonstrated through the use of polishing. Mechanical polishing of Pt-SPE devices offers a viable approach to performance improvement for amperometric gas sensing. © 2016 American Chemical Society

Identification of a rhythmic firing pattern in the enteric nervous system that generates rhythmic electrical activity in smooth muscle

The enteric nervous system (ENS) contains millions of neurons essential for organization of motor behavior of the intestine. It is well established that the large intestine requires ENS activity to drive propulsive motor behaviors. However, the firing pattern of the ENS underlying propagating neurogenic contractions of the large intestine remains unknown. To identify this, we used high-resolution neuronal imaging with electrophysiology from neighboring smooth muscle. Myoelectric activity underlying propagating neurogenic contractions along murine large intestine [also referred to as colonic migrating motor complexes, (CMMCs)] consisted of prolonged bursts of rhythmic depolarizations at a frequency of ∼2 Hz. Temporal coordination of this activity in the smooth muscle over large spatial fields (∼7 mm, longitudinally) was dependent on the ENS. During quiescent periods between neurogenic contractions, recordings from large populations of enteric neurons, in mice of either sex, revealed ongoing activity. The onset of neurogenic contractions was characterized by the emergence of temporally synchronized activity across large populations of excitatory and inhibitory neurons. This neuronal firing pattern was rhythmic and temporally synchronized across large numbers of ganglia at ∼2 Hz. ENS activation preceded smooth muscle depolarization, indicating rhythmic depolarizations in smooth muscle were controlled by firing of enteric neurons. The cyclical emergence of temporally coordinated firing of large populations of enteric neurons represents a unique neural motor pattern outside the CNS. This is the first direct observation of rhythmic firing in the ENS underlying rhythmic electrical depolarizations in smooth muscle. The pattern of neuronal activity we identified underlies the generation of CMMCs

Design and development of financial applications using ontology-based multi-agent systems

Researchers in the field of finance now use increasingly sophisticated mathematical models that require intelligent software on high performance computing systems. Agent models to date that are designed for financial markets have their knowledge specified through low level programming that require technical expertise in software, not normally available with finance professionals. Hence there is a need for system development methodologies where domain experts and researchers and can specify the behaviour of the agent applications without any knowledge of the underlying agent software. This paper proposes an approach to achieve the above objectives through the use of ontologies that drive the behaviours of agents. This approach contributes towards the building of semantically aware intelligent services, where ontologies are used rather than low level programming to dictate the characteristics of the agent applications. This approach is expected to allow more extensive usage of multi-agent systems in financial business applications