251 research outputs found
Representation and design of wavelets using unitary circuits
The representation of discrete, compact wavelet transformations (WTs) as circuits of local unitary gates is discussed. We employ a similar formalism as used in the multiscale representation of quantum many-body wave functions using unitary circuits, further cementing the relation established in the literature between classical and quantum multiscale methods. An algorithm for constructing the circuit representation of known orthogonal, dyadic, discrete WTs is presented, and the explicit representation for Daubechies wavelets, coiflets, and symlets is provided. Furthermore, we demonstrate the usefulness of the circuit formalism in designing WTs, including various classes of symmetric wavelets and multiwavelets, boundary wavelets, and biorthogonal wavelets
Representation and design of wavelets using unitary circuits
The representation of discrete, compact wavelet transformations (WTs) as circuits of local unitary gates is discussed. We employ a similar formalism as used in the multiscale representation of quantum many-body wave functions using unitary circuits, further cementing the relation established in the literature between classical and quantum multiscale methods. An algorithm for constructing the circuit representation of known orthogonal, dyadic, discrete WTs is presented, and the explicit representation for Daubechies wavelets, coiflets, and symlets is provided. Furthermore, we demonstrate the usefulness of the circuit formalism in designing WTs, including various classes of symmetric wavelets and multiwavelets, boundary wavelets, and biorthogonal wavelets
The Physical Conditions and Dynamics of the Interstellar Medium in the Nucleus of M83: Observations of CO and CI
This paper presents CI, CO J=4-3, and CO J=3-2 maps of the barred spiral
galaxy M83 taken at the James Clerk Maxwell Telescope. Observations indicate a
double peaked structure which is consistent with gas inflow along the bar
collecting at the inner Lindblad resonance. This structure suggests that
nuclear starbursts can occur even in galaxies where this inflow/collection
occurs, in contrast to previous studies of barred spiral galaxies. However, the
observations also suggest that the double peaked emission may be the result of
a rotating molecular ring oriented nearly perpendicular to the main disk of the
galaxy. The CO J=4-3 data indicate the presence of warm gas in the nucleus that
is not apparent in the lower-J CO observations, which suggests that CO J=1-0
emission may not be a reliable tracer of molecular gas in starburst galaxies.
The twelve CI/CO J=4-3 line ratios in the inner 24'' x 24'' are uniform at the
2 sigma level, which indicates that the CO J=4-3 emission is originating in the
same hot photon-dominated regions as the CI emission. The CO J=4-3/J=3-2 line
ratios vary significantly within the nucleus with the higher line ratios
occurring away from peaks of emission along an arc of active star forming
regions. These high line ratios (>1) likely indicate optically thin gas created
by the high temperatures caused by star forming regions in the nucleus of this
starburst galaxy.Comment: 15 pages with 10 figures. To appear in the August 10 1998 issue of
The Astrophysical Journa
Distinct features of seizures induced by cocaine and amphetamine analogs
Abstract Seizure-related emergencies caused by stimulants of abuse have been increasing. To better understand the nature of these drug-induced convulsions, we characterized the seizure patterns associated with high doses of cocaine, and the amphetamine analogs, metham-Ž . phetamine, methylenedioxymethamphetamine MDMA and 4-methylaminorex. The features of the stimulant-induced seizures were Ž . Ž . distinct and included the following: 1 the duration of convulsive activity was shortest for cocaine and longest for methamphetamine, 2 Ž . only MDMA produced a secondary clonic phase after the initial ictal event, and 3 4-methylaminorex manifested a very steep dose-response curve. Differential preventive profiles of anticonvulsant agents on the stimulant-induced seizures also were observed. For example, cocaine-related seizures were most effectively prevented by, while methamphetamine-induced seizures were completely refractory to, phenytoin pretreatment. The only anticonvulsants which appeared to influence methamphetamine-related convulsions were diazepam and valproate. A unique feature of 4-methylaminorex was that related seizures were almost completely blocked by the calcium channel blocker, flunarizine.
At-home use of parasacral transcutaneous electrical nerve stimulation for pediatric voiding dysfunction: a randomized controlled trial to assess its safety and feasibility
IntroductionTreating pediatric voiding dysfunction involves behavioral changes that require significant time or medications that are often avoided or discontinued due to side effects. Using parasacral transcutaneous electrical nerve stimulation (PTENS) has shown to have reasonable efficacy, but the safety and feasibility of its off-label use for pediatric voiding dysfunction are not well-established. Concerns have also been raised over treatment adherence. In-home therapy might improve adherence compared with office-based therapy; however, no studies have evaluated in-home feasibility to date. This study aims to assess the safety and feasibility of off-label use of PTENS for pediatric voiding dysfunction.Materials and methodsA single-institution prospective, randomized controlled study was conducted from March 2019 to March 2020. Participants aged 6–18 years diagnosed with voiding dysfunction, overactive bladder, or urinary incontinence were eligible for the study. Those with known neurologic disorders, implanted electrical devices, anatomic lower urinary tract abnormality, and recurrent urinary tract infections and those taking bladder medications were excluded. Children with primary monosymptomatic nocturnal enuresis were also excluded due to previous work suggesting a lack of efficacy. Participants were randomly assigned to receive 12 weeks of urotherapy alone (control) or urotherapy plus at-home PTENS treatment. Families were contacted weekly to assess for adverse events (AEs) and treatment adherence. The primary and secondary outcomes were safety, defined as the absence of AEs and treatment adherence, respectively.ResultsA total of 30 eligible participants were divided into two groups, with 15 participants in each arm. The median age was 9.4 years (interquartile range: 7.7–10.6). In total, 60% were male. Baseline demographics and urotherapy compliance were similar between the two groups. With PTENS use, two AEs were reported, including mild pruritus at the pad site and discomfort when removing pads, while no AEs were noted in the control group. In total, 60% of patients completed three 30-min sessions per week, and all participants were able to complete treatment sessions for at least 10 weeks, involving 30 min of PTENS treatment each time.ConclusionThis randomized controlled study confirms that at-home use of PTENS is feasible with reasonable treatment adherence and minimal AEs. Future collaborative, multi-institutional studies may better determine the efficacy of this treatment modality
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Eye movements and reading in glaucoma: observations on patients with advanced visual field loss
Purpose To investigate the relationship between reading speed and eye movements in patients with advanced glaucomatous visual field (VF) defects and age-similar visually healthy people. Methods Eighteen patients with advanced bilateral VF defects (mean age: 71, standard deviation [SD]: 7 years) and 39
controls (mean age: 67, SD: 8 years) had reading speed measured using short passages of text on a computer set-up incorporating eye tracking. Scanpaths were plotted and analysed from these experiments to derive measures of ‘perceptual span’ (total number of letters read per number of saccades) and ‘text saturation’ (the distance between the first and last fixation on lines of text). Another eye movement measure, termed ‘saccadic frequency’ (total number of saccades made to read a single word), was derived from a separate lexical decision task, where words were presented in isolation. Results Significant linear association was demonstrated between perceptual span and reading speed in patients (R2=0.42) and controls (R2=0.56). Linear association between saccadic frequency during the LDT and reading speed was also found in patients (R2=0.42), but not in controls (R2=0.02). Patients also exhibited greater average text saturation than controls (P=0.004). Conclusion Some, but not all, patients with advanced VF defects read slower than controls using short text passages. Differences in eye movement behaviour may partly account for this variability in patients. These patients were shown to saturate lines of text more during reading, which may explain previously-reported difficulties with sustained reading
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