577 research outputs found
Waveforms and End-to-End Efficiency in RF Wireless Power Transfer Using Digital Radio Transmitter
We study radio-frequency (RF) wireless power transfer (WPT) using a digital
radio transmitter for applications where alternative analog transmit circuits
are impractical. An important paramter for assessing the viability of an RF WPT
system is its end-to-end efficiency. In this regard, we present a prototype
test-bed comprising a software-defined radio (SDR) transmitter and an energy
harvesting receiver with a low resistive load; employing an SDR makes our
research meaningful for simultaneous wireless information and power transfer
(SWIPT). We analyze the effect of clipping and non-linear amplification at the
SDR on multisine waveforms. Our experiments suggest that when the DC input
power at the transmitter is constant, high peak-to-average power ratio (PAPR)
multisine are unsuitable for RF WPT over a flat-fading channel, due to their
low average radiated power. The results indicate that the end-to-end efficiency
is positively correlated to the average RF power of the waveform, and that it
reduces with increasing PAPR. Consequently, digital modulations such as
phase-shift keying (PSK) and quadrature amplitude modeulation (QAM) yield
better end-to-end efficiency than multisines. Moreover, the end-to-end
efficiency of PSK and QAM signals is invariant of the transmission bit rate. An
in-depth analysis of the end-to-end efficiency of WPT reveals that the
transmitter efficiency is lower than the receiver efficiency. Furthermore, we
study the impact of a reflecting surface on the end-to-end efficiency of WPT,
and assess the transmission quality of the information signals by evaluating
their error vector magnitude (EVM) for SWIPT. Overall, the experimental
observations of end-to-end efficiency and EVM suggest that, while employing an
SDR transmitter with fixed DC input power, a baseband quadrature PSK signal is
most suitable for SWIPT at large, among PSK and QAM signals.Comment: Accepted for publication in IEEE Transactions on Microwave Theory and
Technique
Examining California’s Title 22 Community Care Licensing Regulations: The Impact on Inclusive Preschool Settings
Access to general education preschool in California has varied for children with disabilities. One reason for the disparity of educational placement is the preschool regulations outlined in California Department of Education’s Title 22: Community Care Licensing guidelines. These regulations, particularly in preschool, support or hinder preschool inclusion. Examining the preschool section of Title 22 through document analysis resulted in identifying three major themes that embrace or deter inclusive practices: (a) language (i.e., supportive language, antiquated language, and ambiguous language); (b) training, experience, and education; and (c) staff-student ratio. California’s educational leaders should consider these results to provide opportunities for preschool children with disabilities to be in general education environments
Impact: The Visual Communication of Information
Impact: The Visual Communication of Information focuses on the diversity of visual communication created by students, faculty, and staff across California Polytechnic State University, San Luis Obispo. Drawing from a multitude of methods in courses and activities across the campus, the exhibit displays the influences of visual communication in fields ranging from statistical data and geography, to art, design, and engineering, to performance and physics. This project was made possible by a gift from the Austin and Gabriela Hearst Foundation.
This catalog represents the onsite exhibit of the same name, which opened in winter of 2020 at Robert E. Kennedy Library
Multi-Locus Variable-Number Tandem Repeat Profiling of Salmonella enterica Serovar Typhi Isolates from Blood Cultures and Gallbladder Specimens from Makassar, South-Sulawesi, Indonesia
Multi-locus variable-number tandem repeat analysis differentiated 297 Salmonella enterica serovar Typhi blood culture isolates from Makassar in 76 genotypes and a single unique S. Typhi genotype was isolated from the cholecystectomy specimens of four patients with cholelithiasis. The high diversity in S. Typhi genotypes circulating in Makassar indicates that the number of carriers could be very large, which may complicate disease prevention and control
CtIP and MRN promote non-homologous end-joining of etoposide-induced DNA double-strand breaks in G1
Topoisomerases class II (topoII) cleave and re-ligate the DNA double helix to allow the passage of an intact DNA strand through it. Chemotherapeutic drugs such as etoposide target topoII, interfere with the normal enzymatic cleavage/re-ligation reaction and create a DNA double-strand break (DSB) with the enzyme covalently bound to the 5′-end of the DNA. Such DSBs are repaired by one of the two major DSB repair pathways, non-homologous end-joining (NHEJ) or homologous recombination. However, prior to repair, the covalently bound topoII needs to be removed from the DNA end, a process requiring the MRX complex and ctp1 in fission yeast. CtIP, the mammalian ortholog of ctp1, is known to promote homologous recombination by resecting DSB ends. Here, we show that human cells arrested in G0/G1 repair etoposide-induced DSBs by NHEJ and, surprisingly, require the MRN complex (the ortholog of MRX) and CtIP. CtIP's function for repairing etoposide-induced DSBs by NHEJ in G0/G1 requires the Thr-847 but not the Ser-327 phosphorylation site, both of which are needed for resection during HR. This finding establishes that CtIP promotes NHEJ of etoposide-induced DSBs during G0/G1 phase with an end-processing function that is distinct to its resection function
Design of a dual species atom interferometer for space
Atom interferometers have a multitude of proposed applications in space
including precise measurements of the Earth's gravitational field, in
navigation & ranging, and in fundamental physics such as tests of the weak
equivalence principle (WEP) and gravitational wave detection. While atom
interferometers are realized routinely in ground-based laboratories, current
efforts aim at the development of a space compatible design optimized with
respect to dimensions, weight, power consumption, mechanical robustness and
radiation hardness. In this paper, we present a design of a high-sensitivity
differential dual species Rb/Rb atom interferometer for space,
including physics package, laser system, electronics and software. The physics
package comprises the atom source consisting of dispensers and a 2D
magneto-optical trap (MOT), the science chamber with a 3D-MOT, a magnetic trap
based on an atom chip and an optical dipole trap (ODT) used for Bose-Einstein
condensate (BEC) creation and interferometry, the detection unit, the vacuum
system for mbar ultra-high vacuum generation, and the
high-suppression factor magnetic shielding as well as the thermal control
system. The laser system is based on a hybrid approach using fiber-based
telecom components and high-power laser diode technology and includes all laser
sources for 2D-MOT, 3D-MOT, ODT, interferometry and detection. Manipulation and
switching of the laser beams is carried out on an optical bench using Zerodur
bonding technology. The instrument consists of 9 units with an overall mass of
221 kg, an average power consumption of 608 W (819 W peak), and a volume of 470
liters which would well fit on a satellite to be launched with a Soyuz rocket,
as system studies have shown.Comment: 30 pages, 23 figures, accepted for publication in Experimental
Astronom
STE-QUEST - Test of the Universality of Free Fall Using Cold Atom Interferometry
In this paper, we report about the results of the phase A mission study of the atom
interferometer instrument covering the description of the main payload elements, the
atomic source concept, and the systematic error sources
Oscillatory networks of high-level mental alignment::A perspective-taking MEG study
Mentally imagining another's perspective is a high-level social process, reliant on manipulating internal representations of the self in an embodied manner. Recently Wang et al. (2016) showed that theta-band (3–7 Hz) brain oscillations within the right temporo-parietal junction (rTPJ) and brain regions coding for motor/body schema contribute to the process of perspective-taking. Using a similar paradigm, we set out to unravel the extended functional brain network in detail. Increasing the angle between self and other perspective was accompanied by longer reaction times and increases in theta power within rTPJ, right lateral prefrontal cortex (PFC) and right anterior cingulate cortex (ACC). Using Granger-causality, we showed that lateral PFC and ACC exert top-down influence over rTPJ, indicative of executive control processes required for managing conflicts between self and other perspectives. Finally, we quantified patterns of whole-brain phase coupling in relation to the rTPJ. Results suggest that rTPJ increases its theta-band phase synchrony with brain regions involved in mentalizing and regions coding for motor/body schema; whilst decreasing synchrony to visual regions. Implications for neurocognitive models are discussed, and it is proposed that rTPJ acts as a ‘hub’ to route bottom-up visual information to internal representations of the self during perspective-taking, co-ordinated by theta-band oscillations
Locus coeruleus imaging as a biomarker for noradrenergic dysfunction in neurodegenerative diseases.
Pathological alterations to the locus coeruleus, the major source of noradrenaline in the brain, are histologically evident in early stages of neurodegenerative diseases. Novel MRI approaches now provide an opportunity to quantify structural features of the locus coeruleus in vivo during disease progression. In combination with neuropathological biomarkers, in vivo locus coeruleus imaging could help to understand the contribution of locus coeruleus neurodegeneration to clinical and pathological manifestations in Alzheimer's disease, atypical neurodegenerative dementias and Parkinson's disease. Moreover, as the functional sensitivity of the noradrenergic system is likely to change with disease progression, in vivo measures of locus coeruleus integrity could provide new pathophysiological insights into cognitive and behavioural symptoms. Locus coeruleus imaging also holds the promise to stratify patients into clinical trials according to noradrenergic dysfunction. In this article, we present a consensus on how non-invasive in vivo assessment of locus coeruleus integrity can be used for clinical research in neurodegenerative diseases. We outline the next steps for in vivo, post-mortem and clinical studies that can lay the groundwork to evaluate the potential of locus coeruleus imaging as a biomarker for neurodegenerative diseases.Includes MRC, NIHR, Wellcome Trust, H2020 and FP7
Correlation of Circulating Omentin-1 with Bone Mineral Density in Multiple Sclerosis: The Crosstalk between Bone and Adipose Tissue
BACKGROUND: Patients with multiple sclerosis (MS) are at increased risk of osteoporosis and fractures. Adipose tissue-derived adipokines may play important roles in the osteoimmunology of MS. In order to determine whether omentin-1 and vaspin may be related to bone health in MS patients, we compared circulating levels of these recently identified adipokines, between MS patients and healthy controls. METHODS: A total of 35 ambulatory MS patients with relapsing-remitting courses were compared with 38 age- and sex-matched healthy controls. Bone mineral density (BMD) was determined for the lumbar spine (L2-L4) and the proximal femur using dual-energy x-ray absorptiometry. Circulating omentin-1, vaspin, osteocalcin, osteopontin, osteoprotegerin, the receptor activator of nuclear factor-κB ligand, matrix metalloproteinase 9, C-reactive protein and 25-hydroxy vitamin D levels were evaluated by highly specific enzyme-linked immunosorbent assay methods. RESULTS: There was no significant difference between the two groups regarding bone-related cytokines, adipocytokines, and the BMD measurements of patients with MS and the healthy controls. However, in multiple regression analysis, serum omentin-1 levels were positively correlated with BMD at the femoral neck (β = 0.49, p = 0.016), total hip (β = 0.42, p = 0.035), osteopontin (β = 0.42, p = 0.030) and osteocalcin (β = 0.53, p = 0.004) in MS patients. No correlations were found between vaspin, biochemical, and BMD measures in both groups. CONCLUSIONS: Elevated omentin-1 serum levels are correlated with BMD at the femoral neck and the serum levels of osteocalcin and osteopontin in MS patients. Therefore, there is crosstalk between adipose tissue and bone in MS
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