291 research outputs found
IN-SYNC. VIII. Primordial Disk Frequencies in NGC 1333, IC 348, and the Orion A Molecular Cloud
In this paper, we address two issues related to primordial disk evolution in
three clusters (NGC 1333, IC 348, and Orion A) observed by the INfrared Spectra
of Young Nebulous Clusters (IN-SYNC) project. First, in each cluster, averaged
over the spread of age, we investigate how disk lifetime is dependent on
stellar mass. The general relation in IC 348 and Orion A is that primordial
disks around intermediate mass stars (2--5) evolve faster than those
around loss mass stars (0.1--1), which is consistent with previous
results. However, considering only low mass stars, we do not find a significant
dependence of disk frequency on stellar mass. These results can help to better
constrain theories on gas giant planet formation timescales. Secondly, in the
Orion A molecular cloud, in the mass range of 0.35--0.7, we provide
the most robust evidence to date for disk evolution within a single cluster
exhibiting modest age spread. By using surface gravity as an age indicator and
employing 4.5 excess as a primordial disk diagnostic, we observe a
trend of decreasing disk frequency for older stars. The detection of
intra-cluster disk evolution in NGC 1333 and IC 348 is tentative, since the
slight decrease of disk frequency for older stars is a less than 1-
effect.Comment: 25 pages, 26 figures; submitted for publication (ApJ
Neuroinspired unsupervised learning and pruning with subquantum CBRAM arrays.
Resistive RAM crossbar arrays offer an attractive solution to minimize off-chip data transfer and parallelize on-chip computations for neural networks. Here, we report a hardware/software co-design approach based on low energy subquantum conductive bridging RAM (CBRAM®) devices and a network pruning technique to reduce network level energy consumption. First, we demonstrate low energy subquantum CBRAM devices exhibiting gradual switching characteristics important for implementing weight updates in hardware during unsupervised learning. Then we develop a network pruning algorithm that can be employed during training, different from previous network pruning approaches applied for inference only. Using a 512 kbit subquantum CBRAM array, we experimentally demonstrate high recognition accuracy on the MNIST dataset for digital implementation of unsupervised learning. Our hardware/software co-design approach can pave the way towards resistive memory based neuro-inspired systems that can autonomously learn and process information in power-limited settings
Mixed valence Sn doped (CH3NH3)3Bi2Br9 produced by mechanochemical synthesis
Bismuth halides with formula A3Bi2X9, where A is an inorganic or organic cation, show desirable properties as solar absorbers and luminescent materials. Control of structural and electronic dimensionality of these compounds is important to yield materials with good light absorption and charge transport. Here we report mechanochemical reaction of (CH3NH3)3Bi2Br9 with SnBr2 at room temperature in air, yielding a material with strong absorption across the visible region. We attribute this to mixed valence doping of Sn(II) and Sn(IV) on the Bi site. X-ray diffraction shows no secondary phases, even after heating at 200oC to improve crystallinity. X-ray photoelectron spectroscopy suggests the presence of Sn(II) and Sn(IV) states. A similar approach to dope Sn into the iodide analogue (CH3NH3)3Bi2I9 was unsuccessful
Peningkatan Kapasitas Kurikulum 2013 Pendidikan Usia Dini pada Guru dan Pengelola PAUD Al Birru Nasyiatul Aisyiyah
Early Childhood Education (PAUD) is an embryo of children's education in shaping a generation of people who are superior and dignified. Education provided to children aged 0-6 years primarily introduces physical activity to stimulate the child's motoric development, affection and introduce the process of socializing to children. Considering the importance of PAUD, the curriculum 2013 PAUD has now been developed, where previously there was no specific curriculum that could be used in the learning process in PAUD. Applying the curriculum 2013, the teachers still did not have enough capacity to be able to translate the concepts of the curriculum into the learning process. Therefore, training was carried out in an effort to increase capacity in the application of the Curriculum 2013 PAUD. The analytical method used is descriptive analysis and inference. The result of this activity is that there is a change in knowledge about the 2013 PAUD curriculum for the training participants. Participants give evaluators on the implementation of training in general is good. Outcome of this training the participants are required to disseminate the curriculum 2013 PAUD materia
Cu^{2+}-Chelating Mesoporous Silica Nanoparticles for Synergistic Chemotherapy/Chemodynamic Therapy
In this study, a pH-responsive controlled-release mesoporous silica nanoparticle (MSN) formulation was developed. The MSNs were functionalized with a histidine (His)-tagged targeting peptide (B3int) through an amide bond, and loaded with an anticancer drug (cisplatin (CP)) and a lysosomal destabilization mediator (chloroquine (CQ)). Cu2+ was then used to seal the pores of the MSNs via chelation with the His-tag. The resultant nanoparticles showed pH-responsive drug release, and could effectively target tumor cells via the targeting effect of B3int. The presence of CP and Cu2+ permits reactive oxygen species to be generated inside cells; thus, the chemotherapeutic effect of CP is augmented by chemodynamic therapy. In vitro and in vivo experiments showed that the nanoparticles are able to effectively kill tumor cells. An in vivo cancer model revealed that the nanoparticles increase apoptosis in tumor cells, and thereby diminish the tumor volume. No off-target toxicity was noted. It thus appears that the functionalized MSNs developed in this work have great potential for targeted, synergistic anticancer therapies
Zwicky Transient Facility constraints on the optical emission from the nearby repeating FRB 180916.J0158+65
The discovery rate of fast radio bursts (FRBs) is increasing dramatically
thanks to new radio facilities. Meanwhile, wide-field instruments such as the
47 deg Zwicky Transient Facility (ZTF) survey the optical sky to study
transient and variable sources. We present serendipitous ZTF observations of
the CHIME repeating source FRB 180916.J0158+65, that was localized to a spiral
galaxy 149 Mpc away and is the first FRB suggesting periodic modulation in its
activity. While 147 ZTF exposures corresponded to expected high-activity
periods of this FRB, no single ZTF exposure was at the same time as a CHIME
detection. No optical source was found at the FRB location in 683
ZTF exposures, totalling 5.69 hours of integration time. We combined ZTF upper
limits and expected repetitions from FRB 180916.J0158+65 in a statistical
framework using a Weibull distribution, agnostic of periodic modulation priors.
The analysis yielded a constraint on the ratio between the optical and radio
fluences of , corresponding to an optical energy erg for a fiducial 10 Jy ms FRB (90%
confidence). A deeper (but less statistically robust) constraint of can be placed assuming a rate of Jy ms)= hr and
FRB occurring during exposures taken in high-activity windows. The
constraint can be improved with shorter per-image exposures and longer
integration time, or observing FRBs at higher Galactic latitudes. This work
demonstrated how current surveys can statistically constrain multi-wavelength
counterparts to FRBs even without deliberately scheduled simultaneous radio
observation.Comment: Accepted for publication in ApJL, 9 pages, 4 figures, 1 tabl
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