2,426 research outputs found
Bandwidth Efficient Root Nyquist Pulses for Optical Intensity Channels
Indoor diffuse optical intensity channels are bandwidth constrained due to the multiple reflected paths between the transmitter and the receiver which cause considerable inter-symbol interference (ISI). The transmitted signal amplitude is inherently non-negative, being a light intensity signal. All optical intensity root Nyquist pulses are time-limited to a single symbol interval which eliminates the possibility of finding bandlimited root Nyquist pulses. However, potential exists to design bandwidth efficient pulses. This paper investigates the modified hermite polynomial functions and prolate spheroidal wave functions as candidate waveforms for designing spectrally efficient optical pulses. These functions yield orthogonal pulses which have constant pulse duration irrespective of the order of the function, making them ideal for designing an ISI free pulse. Simulation results comparing the two pulses and challenges pertaining to their design and implementation are discussed
Augmenting computer networks
Three methods of augmenting computer networks by adding at most one link per processor are discussed: (1) A tree of N nodes may be augmented such that the resulting graph has diameter no greater than 4log sub 2((N+2)/3)-2. Thi O(N(3)) algorithm can be applied to any spanning tree of a connected graph to reduce the diameter of that graph to O(log N); (2) Given a binary tree T and a chain C of N nodes each, C may be augmented to produce C so that T is a subgraph of C. This algorithm is O(N) and may be used to produce augmented chains or rings that have diameter no greater than 2log sub 2((N+2)/3) and are planar; (3) Any rectangular two-dimensional 4 (8) nearest neighbor array of size N = 2(k) may be augmented so that it can emulate a single step shuffle-exchange network of size N/2 in 3(t) time steps
Some analogs of Zariski's Theorem on nodal line arrangements
For line arrangements in P^2 with nice combinatorics (in particular, for
those which are nodal away the line at infinity), we prove that the
combinatorics contains the same information as the fundamental group together
with the meridianal basis of the abelianization. We consider higher dimensional
analogs of the above situation. For these analogs, we give purely combinatorial
complete descriptions of the following topological invariants (over an
arbitrary field): the twisted homology of the complement, with arbitrary rank
one coefficients; the homology of the associated Milnor fiber and Alexander
cover, including monodromy actions; the coinvariants of the first higher
non-trivial homotopy group of the Alexander cover, with the induced monodromy
action.Comment: Published by Algebraic and Geometric Topology at
http://www.maths.warwick.ac.uk/agt/AGTVol5/agt-5-28.abs.htm
Two Cases of Helicobacter pylori-Negative Gastric Outlet Obstruction in Children
Gastric outlet obstruction (GOO) in children is most commonly caused by idiopathic hypertrophic pyloric stenosis. Prior to proton pump inhibitors and H2 blockers, peptic ulcer disease (PUD) secondary to H. pylori was a cause of GOO. Both patients presented with a history of weight loss, vomiting, and abdominal pain. Their diagnosis of PUD and GOO was made by EGD and UGI. H. pylori testing was negative for both on multiple occasions but still received H. pylori eradication therapy. Patient 1 after failing pharmaceutical management underwent surgery for definitive treatment. Patient 2 underwent six therapeutic pyloric dilations before undergoing surgery as definitive treatment. These cases suggest that GOO secondary to PUD occurs in the absence of H. pylori infection and surgical management can provide definitive therapy
The effect of active toe movement (AToM) on calf pump function and deep vein thrombosis in patients with acute foot and ankle trauma treated with cast - a prospective randomized study
Background Patients with foot and ankle trauma treated with cast are advised to perform toe movements to prevent venous thromboembolism (VTE). Our aim was to determine the effect of active toe movement on asymptomatic deep vein thrombosis (DVT) and venous calf pump function. Methods Patients aged 18–60 years with acute foot and ankle trauma requiring below knee non weight bearing cast were randomized to intervention (regular active toe movement) or control groups (n = 100). Patients had bilateral lower limb venous ultrasound to assess for DVT on discharge from clinic. Patients requiring chemical thromboprophylaxis were excluded. Results 78 completed the study. 27% sustained asymptomatic DVT, with no statistically significant difference in calf pump function or DVT incidence between groups. All DVT's occurred in the injured lower limb. Conclusion Active toe movement is not a viable strategy for thromboprophylaxis in patients with acute foot and ankle trauma treated with cast
Low frequency noise statistics for the breakdown characterization of ultra-thin gate oxides
We have investigated the statistics of low frequency noise in the tunneling
current of ultrathin oxides (2.5nm-4nm) in metal oxide semiconductor capacitors
as a function of the applied voltage stress. The statistical analysis includes
(i) non-Gaussianity (nG), which is a measure of the degree of temporal
correlation in the noise, and (ii) ratio of integrated noise power to the DC
leakage current (R). The occurrence of high peaks in nG indicates the
appearance of new percolation paths, and the subsequent conduction through
these paths is indicated by R. Our results show that the nG and R
characteristics are generic for the oxides of different thickness and growth
quality and have the potential, in conjunction with leakage itself, of being
used as a prognosticator of oxide reliability.Comment: 4 page
A feasibility study of educational tools for osteomalacia
Many people in the UK, particularly people of South Asian origin, are advised to supplement their vitamin D intake, yet most do not. This suggests an unmet educational need. The osteomalacia mind map was developed to meet this need. The mind map contains culturally sensitive images, translated into Urdu and made interactive on a DVD. This study explores the feasibility of a randomised controlled study to measure the effect of education on improving vitamin D knowledge and adherence. This was a pilot and feasibility study. Cluster randomisation was used to avoid inter person contamination. Two South Asian women’s groups were recruited to receive information about osteomalacia either by interactive DVD or an Arthritis Research UK leaflet. Knowledge and compliance were tested before and after the educational interventions via a knowledge questionnaire and the measurement of vitamin D and parathormone levels. The groups were found to be mismatched for knowledge, educational attainment and language at baseline. There were also organisational difficulties and possible confounding due to different tutors and translators. The DVD group had high knowledge at baseline which did not improve. The leaflet group had low knowledge at baseline that did improve. The DVD group had lower parathormone which did not change. The leaflet group had an increase in vitamin D but parathormone remained high. Performing a randomised study with this population utilising an educational intervention was difficult to execute. If cluster randomisation is used, extreme care must be taken to match the groups at baseline
Protosiren and Babiacetus (Mammalia, Sirenia and Cetacea) from the Middle Eocene Drazinda Formation, Sulaiman Range, Punjab (Pakistan)
331-357http://deepblue.lib.umich.edu/bitstream/2027.42/48651/2/ID518.pd
Symptom complexes in patients with seropositive arthralgia and in patients newly diagnosed with rheumatoid arthritis: a qualitative exploration of symptom development
Objective: The aim of this study was to explore symptoms and symptom development during the earliest phases of rheumatoid arthritis (RA) in patients with seropositive arthralgia and patients newly diagnosed with RA
Robust normalization protocols for multiplexed fluorescence bioimage analysis
study of mapping and interaction of co-localized proteins at a sub-cellular level is important for understanding complex biological phenomena. One of the recent techniques to map co-localized proteins is to use the standard immuno-fluorescence microscopy in a cyclic manner (Nat Biotechnol 24:1270–8, 2006; Proc Natl Acad Sci 110:11982–7, 2013). Unfortunately, these techniques suffer from variability in intensity and positioning of signals from protein markers within a run and across different runs. Therefore, it is necessary to standardize protocols for preprocessing of the multiplexed bioimaging (MBI) data from multiple runs to a comparable scale before any further analysis can be performed on the data. In this paper, we compare various normalization protocols and propose on the basis of the obtained results, a robust normalization technique that produces consistent results on the MBI data collected from different runs using the Toponome Imaging System (TIS). Normalization results produced by the proposed method on a sample TIS data set for colorectal cancer patients were ranked favorably by two pathologists and two biologists. We show that the proposed method produces higher between class Kullback-Leibler (KL) divergence and lower within class KL divergence on a distribution of cell phenotypes from colorectal cancer and histologically normal samples
- …