740 research outputs found
Three-fermion problems in optical lattices
We present exact results for the spectra of three fermionic atoms in a single
well of an optical lattice. For the three lowest hyperfine states of Li6 atoms,
we find a Borromean state across the region of the distinct pairwise Feshbach
resonances. For K40 atoms, nearby Feshbach resonances are known for two of the
pairs, and a bound three-body state develops towards the positive
scattering-length side. In addition, we study the sensitivity of our results to
atomic details. The predicted few-body phenomena can be realized in optical
lattices in the limit of low tunneling.Comment: 4 pages, 4 figures, minor changes, to appear in Phys. Rev. Let
Efficient broadband highly dispersive HfO<sub>2</sub>/SiO<sub>2</sub> multilayer mirror for pulse compression in near ultraviolet
Semi-supervised Convolutional Neural Networks for Flood Mapping using Multi-modal Remote Sensing Data
When floods hit populated areas, quick detection of flooded areas is crucial for initial response by local government, residents, and volunteers. Space-borne polarimetric synthetic aperture radar (PolSAR) is an authoritative data sources for flood mapping since it can be acquired immediately after a disaster even at night time or cloudy weather. Conventionally, a lot of domain-specific heuristic knowledge has been applied for PolSAR flood mapping, but their performance still suffers from confusing pixels caused by irregular reflections of radar waves. Optical images are another data source that can be used to detect flooded areas due to their high spectral correlation with the open water surface. However, they are often affected by day, night, or severe weather conditions (i.e., cloud). This paper presents a convolution neural network (CNN) based multimodal approach utilizing the advantages of both PolSAR and optical images for flood mapping. First, reference training data is retrieved from optical images by manual annotation. Since clouds may appear in the optical image, only areas with a clear view of flooded or non-flooded are annotated. Then, a semisupervised polarimetric-features-aided CNN is utilized for flood mapping using PolSAR data. The proposed model not only can handle the issue of learning with incomplete ground truth but also can leverage a large portion of unlabelled pixels for learning. Moreover, our model takes the advantages of expert knowledge on scattering interpretation to incorporate polarimetric-features as the input. Experiments results are given for the flood event that occurred in Sendai, Japan, on 12th March 2011. The experiments show that our framework can map flooded area with high accuracy (F1 = 96:12) and outperform conventional flood mapping methods
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A tele-assessment system for monitoring treatment effects in subjects with spinal cord injury.
We developed a method for remote measurement of balance and leg force in patients with spinal cord injury (SCI). In a group of 21 patients, both telemedicine and conventional clinical assessments were conducted at baseline and six months later. Telemedicine assessments were successfully acquired and transmitted at first attempt. The time required to set up the telemedicine equipment, position the subject, perform the measurements, and then send the data to the university laboratory was approximately 30 minutes. After six months, several motor and sensory functions showed significant changes. There were significant correlations between changes in remotely-measured leg force and changes in several of the American Spinal Injury Association (ASIA) sensory and motor scores. Changes in balance did not show any significant correlations with changes in the ASIA scores. Intra-rater reliability was better than inter-rater reliability. Use of telemedicine to remotely monitor changes in patients with SCI appears promising
Slow magnetization dynamics of small permalloy islands
The conditions that lead to specific domain configurations and the associated switching
characteristics of small permalloy islands were studied by using magnetic force microscopy. By
measuring a large number of particles, it was established that islands that have nonzero remanent
moments ~nonsolenoidal! exist in one of three distinct configurations, namely: ~a! true single
domain, ~b! quasisingle domain with edge closure patterns, and ~c! multidomain with nonuniform
internal magnetization. The configuration depended upon the island width as well as the aspect ratio.
Islands that are 310 nm wide or less are true single domain particles at low aspect ratios
(;1.87) and higher, while islands wider than 500 nm always exhibited edge closure domains even
for very large aspect ratios. In the range between 310 and 500 nm, the onset of single domain
behavior was a function of the aspect ratio and thickness. Our studies involving in situ applied field
similarly revealed the mechanisms of the reversal processes for each of the configurations, which
correlated quite well with the values of the switching fields
Effects of ovary storage time on the quality and meiotic competence of cat oocytes
In this study the growth of Si and SiGe layers fabricated by LPCVD epitaxy was investigated with regard to the realization of extended CMOS devices. especially the vertical MOSFET and the n-MODFET. Main focus was the production of thin, threading-dislocation-free relaxed buffer layers which can be used as virtual substrates for strained Si layers. The pursued concept consists of a low-temperature SiGe layer beneath the intrinsic relaxed buffer layer. Optimizing the low-temperature buffer layer the threading dislocation density could be drastically reduced from 1 x 10 to 1 x 10 cm. The second purpose of this study was the investigation of phosphorous-doped ni-layers for vertical MOSFETs. Using germane and a high-temperature desorption step the ni-doping could be reduced immediately after turning off the phosphine flow resulting in an improved doping profile (1430 to 50 nm/Dec.). Based on optimized layers, vertical n-MOSFETs with a channel length of 100 nm and a gate oxide thickness of 10 nm a transconductance of 200 mS/mm. High-frequency measurements resulted in cut-off frequencies of f =8 GHz and f =19 GHz
Introducing an agricultural app to rice farmers: A pilot study in Can Tho, Vietnam
Plantix is an agricultural app developed by a private company based in Germany which offers a diagnosis and advice for more than 30 crops. It has great potential as a new form of extension service complementing a traditional face-to-face extension service. The CGIAR Plant Health Initiative seeks to introduce the app as part of a package of innovations available for integrated pest and disease management to facilitate behavioral change among farmers. Plantix has been widely used in India but has not yet become very common in Vietnam.
The aim of this pilot study was to test the usability of Plantix app for progressive rural rice growers in Vinh Thanh District, Can Tho City, Vietnam. A group of 15 farmers (5 woman and 11 men) participated in the training on use of the app and provided feedback after a two-week trial.
The results show that the farmers seem to have some trust issues with the app’s diagnosis, as it reportedly failed to identify or distinguish early signs of certain pests and diseases on young rice. Nevertheless, the farmers showed interest in using Plantix app and considered it a useful tool once its early detection capacity is improved. The participants were experienced large-scaled rice farmers who were already quite familiar with the symptoms of regular pests and diseases. They agreed with the knowledge provided by Plantix. The farmers appeared to be conscious of the recommended dosage of chemical pesticides as written on product labels, however, the current local practice still involves overusing. This suggests that additional measures might be needed along with the introduction and dissemination of Plantix for a stronger impact on farmers’ behaviors. The app can be very useful for farmers when they start growing new crops, when there are new pests and diseases, and when they have difficulties distinguishing one disease from others with similar symptoms. Some of the farmers suggested the need for information about new generation pesticides. They also expressed the need for recommendations of specific “top-ranked” pesticide products, to help them navigate the large number of products and brands currently on the market.
Considering the gender division of labor and decision-making, the results show that men are usually responsible for pest and disease management, but women are also involved in decision-making to some extent. It will be interesting to observe how women’s improved knowledge on pest and disease management obtained through Plantix will lead to change in household decisions on pesticide use.
The participating farmers use various sources such as TV, Internet, extension workers, input suppliers and peer farmers as means of accessing information and exchanging knowledge. Male farmers tend to learn new agricultural technologies through social networks within their villages and the Internet more often, while the women do that through the Internet and TV. However, both groups trusted their own experience the most. Therefore, introducing the community’s key farmers to new technologies though demonstration and success stories could work as a strategy to ignite behavior change among peer farmers. In addition, communication via the Internet and TV could quickly reach a large number of farmers. Involving input suppliers and extension workers in the introduction of the Plantix app could also be helpful.
While this pilot study focused on large-scaled farmers, there are smallholder farmers from poor households in some remote areas in the Mekong Delta. Their needs and knowledge may be significantly different from those of progressive farmers. Introducing the app to different types of farmers can help us understand the diverse needs and priorities of farmers in the process of digitalization
Efficient broadband highly dispersive HfO_2/SiO_2 multilayer mirror for pulse compression in near ultraviolet
We report on design, production and implementation of a highly dispersive broadband dielectric multilayer mirror covering near ultraviolet range from 290 nm to 350 nm. The described mirrors, having 92% spectrally averaged reflectance in the ultraviolet range and ~85 fs of group delay difference, that allow compression to ~7 fs, provide a strong foundation for generation of few-fs pulses in the near ultraviolet
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