cssi/SciSciGPT-SciSciNet huggingface dataset:
Comparison of least-squares vs. maximum likelihood estimation for standard spectrum technique of β−γ coincidence spectrum analysis

Abstract The spectrum deconvolution analysis tool (SDAT) software code was written and tested at The University of Texas at Austin utilizing the standard spectrum technique to determine activity levels of Xe-131m, Xe-133m, Xe-133, and Xe-135 in β–γ coincidence spectra. SDAT was originally written to utilize the method of least-squares to calculate the activity of each radionuclide component in the spectrum. Recently, maximum likelihood estimation was also incorporated into the SDAT tool. This is a robust statistical technique to determine the parameters that maximize the Poisson distribution likelihood function of the sample data. In this case it is used to parameterize the activity level of each of the radioxenon components in the spectra. A new test dataset was constructed utilizing Xe-131m placed on a Xe-133 background to compare the robustness of the least-squares and maximum likelihood estimation methods for low counting statistics data. The Xe-131m spectra were collected independently from the Xe-133 spectra and added to generate the spectra in the test dataset. The true independent counts of Xe-131m and Xe-133 are known, as they were calculated before the spectra were added together. Spectra with both high and low counting statistics are analyzed. Studies are also performed by analyzing only the 30 keV X-ray region of the β–γ coincidence spectra. Results show that maximum likelihood estimation slightly outperforms least-squares for low counting statistics data.
Classical foundations of algorithms for solving positive definite Toeplitz equations

The ongoing development and analysis of efficient algorithms for solving positive definite Toeplitz equations is motivated to a large extent by the importance of these equations in signal processing applications. The role of positive definite Toeplitz matrices in this and other areas of mathematics and engineering stems from Schur's study of bounded analytic functions on the unit disk, and Szegő's theory of polynomials orthogonal on the unit circle. These ideas underlie several Toeplitz solvers, and provide a useful framework for understanding the relationships among these algorithms. In this paper we give an overview of several direct algorithms for solving positive definite Toeplitz systems of linear equations from this classical viewpoint.
Diagnosis and management of pre-eclampsia: an update.

Pre-eclampsia is a significant, multifactorial, multiorgan disease affecting 5%–8% of all pregnancies in the US where it is the third leading cause of maternal mortality. Despite improvements in the diagnosis and management of pre-eclampsia, severe complications can occur in both the mother and the fetus, and there is no effective method of prevention. Early detection and identification of pregnant women most at risk of developing the disease have proven challenging, but recent efforts combining biochemical and biophysical markers are promising. Efforts at prevention of pre-eclampsia with aspirin and calcium have had limited success, but research on modifiable risk factors, such as obesity surgery, are encouraging. Obstetric management of severe pre-eclampsia focuses on medical management of blood pressure and prevention of seizures using magnesium sulfate, but the ultimate cure remains delivery of the fetus and placenta. Timing of delivery depends on several factors, including gestational age, fetal lung maturity, and most importantly, disease severity. Anesthetic management includes regional anesthesia with careful evaluation of the patient’s airway, volume status, and coagulation status to reduce morbidity and mortality. The potential complications of general anesthesia, including intracranial hemorrhage, in these patients make regional anesthesia the preferred choice in many cases. Nevertheless, it is important to be aware of the contraindications to neuraxial anesthesia and to prepare always for the possibility of encountering a difficult airway.
Use of a perfluorochemical emulsion to improve oxygenation in a solid tumor

Abstract The ability of the perfluorochemical emulsion, Fluosol-DA, to oxygenate the naturally-occurring hypoxic cells of solid tumors was examined. BALB/c mice bearing EMT6 mouse mammary tumors were given in a single i.v. injection of 0.015 ml/g of Fluosol, and were then treated with 95% O25% CO 2 for 30 min before irradiation with graded doses of X rays. The pretreatment increased the cytotoxic effect of the radiation, as assayed by colony formation in vitro . The dose-response curve for the combination regimen was parallel to that for radiation alone, but was offset towards lower survivals. This change is consistent with the change which would be expected if the pretreatment decreased the proportion of hypoxic cells in the tumors. Studies with unoxygenated perfluorochemical emulsions in vivo and in vitro and studies with O2CO2 alone in vivo suggested that the survival curve changes did not reflect either direct cytotoxic effects of the perfluorochemical emulsion or the O2CO2-breathing, or radiosensitizing or physiologic effects of either agent alone. The data reported here suggest that oxygenated perfluorochemical emulsions may decrease the proportion of hypoxic cells in solid animal tumors and encourage further preclinical evaluation of these agents as potential adjuvants to radiotherapy.
Xenon transit through the oliguric human kidney: Analysis by maximum likelihood

Xenon transit through the oliguric human kidney: Analysis by maximum likelihood. The method of maximum likelihood has been used to analyze xenon transit through the kidney in normal man and patients with acute oliguric renal failure. Xenon transit was assessed by injection of indicator into the renal artery and external counting. Maximum likelihood provided not only a statistically "best" solution but also much greater resolution of exponential functions with similar t½ than graphical techniques permit. The analysis has provided strong evidence for a marked reduction in the flow rate of the most rapid — or cortical — flow component in acute oliguric states. In normal subjects this flow rate by computer analysis ranged from 277 to 581 (mean: 426 ml/100 g/min), and it showed a striking concordance with values derived from graphical analysis. In patients with acute renal failure neither a shunt nor an early rapid component was found by computer analysis: flow ranged from 90 to 159 ml/100 g/min. An additional exponential function was identified in two patients under special circumstances. The increase in cortical vascular resistance in patients with acute renal failure is sufficient to account for the failure of function. Furthermore, cortical flow is reduced to levels which normally characterize medullary perfusion, a larger flow reduction than suggested by earlier analyses. Le transit du Xenon radioactif a travers le rein humain oligurique: analyse par la methode de la probabilite maximale. La methode de la probabilite maximale a ete utilisee pour l'analyse du transit renal du Xenon chez l'homme normal et chez des malades atteints d'insuffisance renale aigue oligurique. Le transit du Xenon a travers le rein a ete evalue par l'injection de l'indicateur dans l'artere renale et son comptage externe. La probabilite maximale a fourni non seulement la solution statistiquement la meilleure mais aussi une resolution beaucoup plus grande des fonctions exponentielles, avec des t1/2; semblables, que ne le permet la methode graphique. L'analyse a fourni des arguments solides pour une reduction importante du debit de la composante rapide, c'est-a-dire corticale, au cours des etats oliguriques. Chez le sujet normal ce debit, calcule par analyse par ordinateur, varie de 277 a 581 avec une moyenne de 426 ml/100 g/minet montre une concordance remarquable avec les valeurs obtenues par analyse graphique. Chez les malades atteints d'insuffisance renale aigue ni shunt ni composante rapide precoce n'ont ete identifies par l'analyse: le debit variait de 90 a 159 ml/100 g/min. Une fonction exponentielle supplemental a ete identifiee chez deux malades, dans des circonstances particulieres. L'augmentation de la resistance vasculaire corticale chez des malades atteints d'insuffisance renale aigue est suffisante pour rendre compte de la suppression de la fonction renale. De plus le debit cortical est reduit a des valeurs qui caracterisent normalement la perfusion medullaire, c'est-a-dire que la reduction du debit est plus importante que ne le suggeraient les analyses anterieures.
Electric field dependence of paraconductivity

Abstract We have studied the suppression caused by an applied electric field of the fluctuations (which are responsible for the paraconductivity seen above the superconducting transition) in aluminum films. Of particular interest is a comparison between data taken in the temperature range where the zero-bias conductivity is approximately that predicted by Azlamazov and Larkin and data taken in the temperature range (further from Tc) where significant deviations from their expression are observed.
A novel cytotoxic flavonoid glycoside from Physalis angulata

Abstract A new flavonol glycoside, myricetin 3-O-neohesperidoside (1) was isolated from a cytotoxic MeOH extract of the leaves of Physalis angulata. Compound 1 showed remarkable cytotoxicity in vitro against murine leukemia cell line P-388, epidermoid carcinoma of the nasopharynx KB-16 cells, and lung adenocarcinoma A-549 with ED50 values of 0.048, 0.50 and 0.55 μg ml−1, respectively.
Who Counsels Parents of Newborns Who Are Carriers of Sickle Cell Anemia or Cystic Fibrosis

Our objective was to describe: 1) physicians’ knowledge of whether genetic counseling is provided to parents of newborns with sickle cell trait (SCT) or who are cystic fibrosis carriers (CFC), and 2) the prevalence of genetic counseling provided by primary care physicians. We conducted a cross-sectional descriptive survey of 600 randomly-sampled Michigan-based pediatricians and family physicians, assessing physician knowledge of where and whether genetic counseling is received by parents whose newborns are carriers. Chi-squared testing determined associations between genetic counseling location and physician demographic characteristics. Our response rate was 62 %: 298 (84 %) provided infant well care (183 pediatricians, 115 family physicians). Most respondents were non-Hispanic White (65 %). Virtually all physicians believed parents whose newborns are carriers of either SCT or CFC should receive some genetic counseling (from the physician and/or another source), yet 20 % reported that parents of newborns with SCT did not receive counseling. Parents of infants with CFC received more counseling overall (92 % vs. 80 %; p < 0.01) and were counseled more frequently by genetic counselors or specialty centers than parents of newborns with SCT (85 % vs. 60 %; p < 0.01). Although physicians agreed that parents whose newborns are carriers should receive genetic counseling, fewer parents of newborns with SCT than with CFC received counseling from any source. This finding strongly suggests the need for further education and investigation of this apparent health disparity.
A novel Transcript is Up-Regulated by Fasting in the Hypothalamus and Enhances Insulin Signalling

A transcript of unknown function, regulated by fasting and feeding, was identified by microarray analysis. The transcript is up-regulated in the fasting state. An 1168-bp cDNA was cloned from rat hypothalamus and sequenced. This sequence is consistent with adipogenesis down-regulating transcript 3 (AGD3) (also known as human OCC-1) mRNA. A protein sequence identical to AGD3 was determined by mass spectrometry. In the rat brain, AGD3 mRNA is distributed in the arcuate nucleus, ventromedial hypothalamus, amygdaloid nuclei, hippocampus, and somatic cortex. Double in situ hybridisation showed that AGD3 mRNA is co-localised with pro-opiomelanocortin and neuropeptide Y in arcuate nucleus neurones. AGD3 binds with insulin receptor substrate 4 and increases insulin-stimulated phospho-Akt and regulates AMP-activated protein kinase and mammalian target of rapamycin downstream target S6 kinase phosphorylation.
BCG immunotherapy: effects of dose and route of administration on survival of mice bearing established tumors.

Bacillus Calmette-Guerin (BCG) was administered in various doses by four different routes to C3H/HeJ mice bearing well-established syngeneic MC-42 fibrosarcomas. Injections of BCG into established primary tumors decreased survival of tumor-bearing mice as compared to saline-injected controls. Of the three dosage groups, high-dose (10(8) viable organisms) intralesional BCG was most detrimental. The injection of low-dose BCG (10(4) organisms) into established tumors or subcutaneously at a distant site also shortened host survival times. Other subcutaneous injections and injections of BCG into the peritoneal or pleural cavities had no significant effect on survival, regardless of dosage. The dose-dependent effects of BCG immunotherapy which may prolong or shorten survival are discussed.
Clinical analysis of the effect of intraarterial cytoreductive chemotherapy in the treatment of lacrimal gland adenoid cystic carcinoma

Purpose To determine the effect of intraarterial cytoreductive chemotherapy (IACC) as an adjunct to conventional surgery and radiation therapy for lacrimal gland adenoid cystic carcinoma (ACC). Design A retrospective, comparative, interventional case series. Methods setting: Institutional. patient population: Nine consecutive patients with lacrimal gland ACC were treated with IACC, followed by orbital exenteration and chemoradiotherapy. This case series was compared with a series of seven patients treated by conventional local therapies in the same institution. intervention procedure: Clinical records, imaging studies, histologic sections, and archival specimens from all 16 patients were reviewed. Information analyzed included site of disease, histologic characteristics, extent of disease, incidence of locoregional recurrence or distant metastases, and disease-free survival and overall survival time. main outcome measure: The effect of IACC was assessed by the radiographic and histologic response and survival outcome in comparison to a historical cohort of patients managed by conventional local therapies. Results The difference between the carcinoma cause-specific death rate of the study group versus conventional treatment was significant (P = .029, log rank test). The cumulative 5-year carcinoma cause-specific death rate in the IACC treated group was 16.7% compared with 57.1% in the conventional treatment group. The cumulative 5-year recurrence rate in the IACC treated group was 23.8% compared with 71.4% in the conventional treatment group. Conclusions The preliminary data suggest that IACC as an integral component of a multimodal treatment strategy is potentially effective in improving local disease control and overall disease-free survival in lacrimal gland adenoid cystic carcinoma.
Family Factors Associated With High Academic Competence in Former Head Start Children at Third Grade

Most studies of gifted students have looked at already identified groups, often convenience samples. This study takes a more epidemiological approach. Of the 5,400 children in the National Head Sta...
Preventing and treating sexual abuse in children with disabilities: use of a team model of intervention

Abstract The general effects of poverty, unemployment, alcohol and drug abuse, or other social problems are likely to be entangled with the specific effects of sexual abuse. The team is the most appropriate model for the prevention and treatment of the complex issue of sexual abuse in children with disabilities. Advanced practice pediatric nurses can play a key role as team leaders, providing much-needed expertise on this issue of sexual abuse. The purposes of this article are to address the needs of children with disabilities who are in the public school system and to describe how a team model, with an advanced practice pediatric nurse as team leader, could be used to identify and treat children with disabilities who have been sexually abused. Copyright 2002, Elsevier Science (USA). All rights reserved.
Excess enthalpies and excess volumes for (butane + ethanol) at the temperatures (298.15, 323.15, and 348.15) K and the pressures (5, 10, and 15) MPa

Abstract Excess molar enthalpies H E m and excess molar volumes V E m have been determined for { x CH 3 (CH 2 ) 2 CH 3 +(1 - x )CH 3 (CH 2 ) 2 CH 2 OH} at the temperatures (298.15, 323.15, and 348.15) K and at the pressures (5, 10, and 15) MPa. The results are explained in terms of chemical, physical, and structural effects. A comparison is made of (∂ H E m /∂ p )τ, the pressure coefficient of H E m , as determined directly from the H E m results and as calculated from V E m and the temperature derivative of V E m .
Studies of blood pressure, heart rate, and the electrocardiogram in adult twins.

Abstract Studies of blood pressure, heart rate, and the electrocardiogram have been analyzed for 53 pairs of twins. All subjects were over 18 years of age, and judged to be in good general health on the basis of histories of health, complete medical examinations, and laboratory tests. Every effort was made to maintain the basal state during the course of the study and to assure comparability for the two members of the pairs of twins. In a comparative analysis of the different measurements taken a strong genetic component of variability was found in the QRS and Q-T intervals of the electrocardiogram. Systolic, diastolic, and mean pressures also gave some indication of genetic variability, but these measurements were found to be most importantly characterized by sex influences.
Gait kinematics after taping in participants with chronic ankle instability.

Context: Chronic ankle instability is characterized by repetitive lateral ankle sprains. Prophylactic ankle taping is a common intervention used to reduce the risk of ankle sprains. However, little research has been conducted to evaluate the effect ankle taping has on gait kinematics. Objective: To investigate the effect of taping on ankle and knee kinematics during walking and jogging in participants with chronic ankle instability. Design: Controlled laboratory study. Setting: Motion analysis laboratory. Patients or Participants: A total of 15 individuals (8 men, 7 women; age = 26.9 ± 6.8 years, height = 171.7 ± 6.3 cm, mass = 73.5 ± 10.7 kg) with self-reported chronic ankle instability volunteered. They had an average of 5.3 ± 3.1 incidences of ankle sprain. Intervention(s): Participants walked and jogged in shoes on a treadmill while untaped and taped. The tape technique was a traditional preventive taping procedure. Conditions were randomized. Main Outcome Measure(s): Frontal-plane and sagittal-plane ...
Beyond the threshold: an etiological bridge between hypoxia and immunity in preeclampsia

Taking a cue from the recent workshop 'Preeclampsia--a Pressing Problem' sponsored by the National Institutes of Child Health and Human Development, this review article takes a fresh look at hypoxia and a dysfunctional immune system as the key contributors to the etiology of preeclampsia and the mechanisms involved therein. In the context of epidemiological research on the intricate and multifactorial nature of preeclampsia, we focus on hypoxia as an upstream regulator of preeclampsia and its consequences in a model compromised by a deficiency in key pregnancy compatible immune modulators. It has been proposed that placental hypoxia releases cytotoxic factors produced at the maternal-fetal interface into the circulation to manifest the maternal symptoms associated with preeclampsia. However, it is not clear how this mechanism is empowered in pregnant women. Does systemic hypoxia exert preeclampsia-like effects on pregnancy? Are these effects further manifested by intrinsic inflammation in the absence of key immune modulators such as IL-10? Thus, it is of paramount importance that in vivo models be developed wherein the role of systemic hypoxia can be evaluated for preeclampsia-causing events. We present a discussion on whether prolonged exposure to hypoxia can lead to a perpetual cycle of compartmentalized uteroplacental tissue damage, release of anti-angiogenic and vasoconstrictive factors that impair trophoblast invasion and promote systemic vascular resistance resulting in the maternal syndrome.
Calculation of approximate propagation characteristics for any given two-dimensional optical waveguide

An approximation technique of determining propagation characteristics of a given cross-section graded-index optical waveguide is presented. The numerical technique gives very short computational times and is easy to use.
Real-time computer controlled backscatter measurement of optical fibres

Abstract The software implementation of a real-time computer-controlled backscatter measurement system for a high standard conformance testing procedure for optical fibres is discussed. Optical time domain reflectometry (OTDR) techniques are employed to test fibre reels along or at the end of a production line. A high speed computer is integrated with such a device to automate a chain of practical test procedures. Significant enhancements have been achieved with the use of fast computer integration, notably up to an eight-fold reduction in test time with no loss of measurement accuracy, when compared to a current commercial system.
Schizophrenia and the mechanisms of conscious integration

This article considers the possibility that defective interactions among distributed brain areas may underlie certain dysfunctions of conscious integration such as those seen in schizophrenia. Recent experimental evidence obtained using whole-head magnetoencephalography during binocular rivalry is first reviewed. The results outline a cortical network that underlies conscious integration in the normal brain. This network is not localized to a small part of the brain but it is distributed over frontal, parietal, temporal, and occipital areas. Large-scale simulations of the dynamics of thalamocortical integration are then examined. These studies indicate that several factors can affect the rapid integration of the activity of distributed thalamocortical regions and the resulting behavioral performance. These simulations show that an altered dynamics of corticothalamic and corticocortical re-entrant circuits can result from increased conduction delays, blockade of voltage-dependent connections, reduced synaptic density, and disruptions of the local connectivity within a single cortical area. It can also result from alterations in the activity of diffuse ascending systems that lead to defective reinforcement of integrated activity patterns. Finally, the article briefly reviews theoretical measures of the integration of multiple brain areas, such as measures of functional clustering. These measures have been applied to PET data obtained from schizophrenic subjects and controls while performing cognitive tasks. The results show a change in the functional interactions among distributed brain areas in schizophrenics despite the absence of a change in activation patterns. The possibility is raised that disruption of re-entrant interactions among cortical areas may contribute to the pathophysiology of schizophrenia.
RNA surveillance-an emerging role for RNA regulatory networks in aging.

In this review, we describe recent advances in the field of RNA regulatory biology and relate these advances to aging science. We introduce a new term, RNA surveillance, an RNA regulatory process that is conserved in metazoans, and describe how RNA surveillance represents molecular cross-talk between two emerging RNA regulatory systems—RNA interference and RNA editing. We discuss how RNA surveillance mechanisms influence mRNA and microRNA expression and activity during lifespan. Additionally, we summarize recent data from our own laboratory linking the RNA editor, ADAR, with exceptional longevity in humans and lifespan in Caenorhabditis elegans. We present data showing that transcriptional knockdown of RNA interference restores lifespan losses in the context of RNA editing defects, further suggesting that interaction between these two systems influences lifespan. Finally, we discuss the implications of RNA surveillance for sarcopenia and muscle maintenance, as frailty is a universal feature of aging. We end with a discussion of RNA surveillance as a robust regulatory system that can change in response to environmental stressors and represents a novel axis in aging science.
Nanoscale Glassification of Gold Substrates for Surface Plasmon Resonance Analysis of Protein Toxins with Supported Lipid Membranes

Surface plasmon resonance (SPR) spectroscopy, a powerful tool for biosensing and protein interaction analysis, is currently confined to gold substrates and the relevant surface chemistries involving dextran and functional thiols. Drawbacks of using self-assembled monolayers (SAMs) for SPR-related surface modification include limited stability, pinhole defects, bioincompatibility, and nonspecific protein adsorption. Here we report the development of stable nanometer-scale glass (silicate) layers on gold substrates for SPR analysis of protein toxins. The nanoscale silicate layers were built up with layer-by-layer deposition of poly(allylamine hydrochloride) and sodium silicate, followed by calcination at high temperature. The resulting silicate films have a thickness ranging from 2 to 15 nm and demonstrate outstanding stability in flow cell conditions. The use of these surfaces as a platform to construct supported bilayer membranes (SBMs) is demonstrated, and improved performance against protein adsorption ...
Isolation-improved LTE MIMO antenna for laptop-computer applications

A simple technique for achieving enhanced isolation between two long-term evolution (LTE) antennas operating at the LTE700/2300/2500 band for the multiple-input multiple-output (MIMO) operation in the laptop computer is presented. The two antennas are mounted along the top edge of the supporting metal plate, which is generally disposed on the inner surface of the upper cover of the laptop computer. Improved isolation (simulated S 21 better than −17 dB in the LTE700 band and −30 dB in the LTE2300/2500 bands) between the two antennas is easily achieved. By arranging a pair of the isolation elements at two separate null current locations of the excited surface current distribution of the LTE700-band modes of the two antennas can improve isolation in the LTE700 band. It can effectively cause weaker surface currents flowing along the top edge of the supporting metal plate. Over the lower and upper bands, the antenna efficiencies are about 46–58% and 50–68%, respectively.
General Education Teachers' Beliefs, Skills, and Practices in Planning for Mainstreamed Students with Learning Disabilities

The purpose of this study was to investigate general education teachers' beliefs, skills, and practices in planning and making adaptations for students with learning disabilities (LD) mainstreamed into general education. Participating teachers were identified by administrators and peers as being effective in working with students with LD. Sixty teachers (20 elementary, 20 middle school, and 20 high school) completed a survey instrument assessing teachers' beliefs, skills, and practices. A subset of the initial cohort of teachers (n = 12) also participated in extensive interviews and classroom observations to provide additional insight into their adaptive instructional practices. Results indicated that even among skilled teachers gaps exist between beliefs, practices, and skills. Discussion focuses on teacher beliefs, skills, and practices and differences among teachers in the three grade groupings.
Dynamical systems and variational inequalities

The variational inequality problem has been utilized to formulate and study a plethora of competitive equilibrium problems in different disciplines, ranging from oligopolistic market equilibrium problems to traffic network equilibrium problems. In this paper we consider for a given variational inequality a naturally related ordinary differential equation. The ordinary differential equations that arise are nonstandard because of discontinuities that appear in the dynamics. These discontinuities are due to the constraints associated with the feasible region of the variational inequality problem. The goals of the paper are two-fold. The first goal is to demonstrate that although non-standard, many of the important quantitative and qualitative properties of ordinary differential equations that hold under the standard conditions, such as Lipschitz continuity type conditions, apply here as well. This is important from the point of view of modeling, since it suggests (at least under some appropriate conditions) that these ordinary differential equations may serve as dynamical models. The second goal is to prove convergence for a class of numerical schemes designed to approximate solutions to a given variational inequality. This is done by exploiting the equivalence between the stationary points of the associated ordinary differential equation and the solutions of the variational inequality problem. It can be expected that the techniques described in this paper will be useful for more elaborate dynamical models, such as stochastic models, and that the connection between such dynamical models and the solutions to the variational inequalities will provide a deeper understanding of equilibrium problems.
Large Margin Gaussian Mixture Modeling for Phonetic Classification and Recognition

We develop a framework for large margin classification by Gaussian mixture models (GMMs). Large margin GMMs have many parallels to support vector machines (SVMs) but use ellipsoids to model classes instead of half-spaces. Model parameters are trained discriminatively to maximize the margin of correct classification, as measured in terms of Mahalanobis distances. The required optimization is convex over the model's parameter space of positive semidefinite matrices and can be performed efficiently. Large margin GMMs are naturally suited to large problems in multiway classification; we apply them to phonetic classification and recognition on the TIMIT database. On both tasks, we obtain significant improvement over baseline systems trained by maximum likelihood estimation. For the problem of phonetic classification, our results are competitive with other state-of-the-art classifiers, such as hidden conditional random fields.
Estimating the number of signals in presence of colored noise

In this paper, statistical ranking and selection theory is used to estimate the number of signals present in colored noise. The data structure follows the well-known Multiple Signal Classification (MUSIC) model. We deal with the eigenanalyses of a matrix, using the MUSIC model and colored noise. The data matrix can be written as the product of a covariance matrix and the inverse of second covariance matrix. We propose a multistep selection procedure to construct a confidence interval on the number of signals present in a data set. Properties of this procedure are stated and proved. Those properties are used to compute the required parameters (procedure constants). Numerical examples are given to illustrate our theory.
GRACE-2: integrating fine-grained application adaptation with global adaptation for saving energy

Energy efficiency has become a primary design criterion for mobile multimedia devices. Prior work has proposed saving energy through coordinated adaptation in multiple system layers, in response to changing application demands and system resources. The scope and frequency of adaptation pose a fundamental conflict in such systems. The Illinois GRACE project addresses this conflict through a hierarchical solution which combines: 1) infrequent (expensive) global adaptation that optimises energy for all applications in the system, 2) frequent (cheap) per-application (or per-app) adaptation that optimises for a single application at a time. This paper demonstrates the benefits of the hierarchical adaptation through a second-generation prototype, GRACE-2. Specifically, it shows that in a network bandwidth constrained environment, per-app application adaptation yields significant energy benefits over and above global adaptation.
Aperiodic accumulation of cyclic peritidal carbonate

Tabulation of thickness data on nearly 3000 Proterozoic and Paleozoic peritidal carbonate cycles indicates that metre-scale facies associations exhibit exponential thickness frequency distributions. Because carbonate deposition occurs during infilling of available space between sea level and the surface of the preceding cycle, and because the rate of generation of accommodation space is ultimately determined by rates of platform subsidence, thicknesses of individual cycles must record the duration of time since deposition of underlying units. Exponential thickness distributions therefore require either that upward-shoaling carbonates record aperiodic accumulation, or that any periodic forcing manifest during sedimentation has been masked by the vagarious nature of depositional processes. Such a conclusion is contrary to interpretation of such carbonate units as originating from high-frequency eustatic change. In addition, exponential thickness distributions and sequence thickness structures are replicated when assuming a random probability of carbonate deposition under conditions of constant subsidence. The nature of cycle thickness distributions therefore invalidates virtually any endeavor to derive an average depositional period from mean cycle thicknesses, and refutes the use of such estimates as proxy records of past sea-level oscillation frequency, whether they are related to Milankovitch-band climate forcing or to any other periodic process.
Stochastic radiative transfer model for mixture of discontinuous vegetation canopies

Modeling of the radiation regime of a mixture of vegetation species is a fundamental problem of the Earth’s land remote sensing and climate applications. The major existing approaches, including the linear mixture model and the turbid medium (TM) mixture radiative transfer model, provide only an approximate solution to this problem. In this study, we developed the stochastic mixture radiative transfer (SMRT) model, a mathematically exact tool to evaluate radiation regime in a natural canopy with spatially varying optical properties, that is, canopy, which exhibits a structured mixture of vegetation species and gaps. The model solves for the radiation quantities, direct input to the remote sensing/climate applications: mean radiation fluxes over whole mixture and over individual species. The canopy structure is parameterized in the SMRT model in terms of two stochastic moments: the probability of finding species and the conditional paircorrelation of species. The second moment is responsible for the 3D radiation effects, namely, radiation streaming through gaps without interaction with vegetation and variation of the radiation fluxes between different species. We performed analytical and numerical analysis of the radiation effects, simulated with the SMRT model for the three cases of canopy structure: (a) non-ordered mixture of species and gaps (TM); (b) ordered mixture of species without gaps; and (c) ordered mixture of species with gaps. The analysis indicates that the variation of radiation fluxes between different species is proportional to the variation of species optical properties (leaf albedo, density of foliage, etc.) Gaps introduce significant disturbance to the radiation regime in the canopy as their optical properties constitute major contrast to those of any vegetation species. The SMRT model resolves deficiencies of the major existing mixture models: ignorance of species radiation coupling via multiple scattering of photons (the linear mixture model) or overestimation of this coupling due to neglecting spatial clumping of species (the TM approach). Thus, based on the former experience with mixture modeling, this study establishes an advanced theoretical basis for future mixture applications. r 2007 Elsevier Ltd. All rights reserved.
High energy plafond fractures treated by a spanning external fixator initially and followed by a second stage open reduction internal fixation of the articular surface--preliminary report.

Abstract Early open reduction and internal fixation (ORIF) with plates and screws for plafond injuries caused by skiing initially reported by Ruedi and Allgower proved inadequate for the treatment of high-energy motor vehicle accident type injuries. The purpose of our study was to review our treatment protocol using a spanning external fixator placed semi-emergently medially across the joint and a later staged ORIF of just the articular surface to achieve and maintain anatomic reduction. Methods : We preformed a retrospective study of 35 patients with 37 highly comminuted severe (OTA 43-B3 and -C3 or Ruedi type II or III) tibial plafond fractures treated by a single surgeon. All patients were treated with an initial spanning unilateral external fixator and subsequent ORIF. Radiographs were examined for: classification, number of pieces of the tibial dome, evidence of ground-glass comminution (more than three pieces Results : Evidence of ground glass comminution existed in 26/37 patients (70%). Following ORIF, articular reduction was perfect (0–1mm displacement) in 29/36 (81%), imperfect (1–3mm) in 6/36 (17%) and poor (>3mm) in 1/36 (3%) cases. Joint alignment was anatomical in 35/37 (96%), with 15° anterior angulation in one patient and 5° valgus angulation in another patient. Radiographic arthritis was present in 10/36 patients (28%) at latest follow-up. Joint distraction at time of reduction was present in 27/37 patients (73%). A total of 25/37 patients (65%) had no post-operative complications, while 3/37 (8%) had a joint infection requiring one patient to have hardware removed. A total of 4/37 (11%) showed loss of reduction at latest follow-up. A total of 3/37 (8%) had a secondary arthrodesis; A total of 1 (3%) had a primary arthrodesis; 1 (3%) diabetic man had a below-knee amputation after a failed arthrodesis. Discussion and conclusion : We treat severe tibial plafond fractures with a spanning external fixator at the time of injury, wait between 10 and 21 days to allow for soft tissue healing, and then perform a limited ORIF of the articular surface with canulated screws. In a group of high-energy plafond fractures, we achieved 81% good to excellent results with this protocol. We conclude that use of a spanning external fixator with delayed ORIF compares favorably with the literature.
Lewis Mumford's idea of community in an urban world

It is a daunting task to recover a usable Mumford from his vast body of writing, myriad ideas and public career over a span of seventy years. These four books make a substantial contribution to that end. Their shared virtues are clarity and thoughtfulness supported by firm scholarship. Useful perspectives are provided on modernization, social ecology, community planning and the human condition. Novak assembles and illuminates a historically important body of letters. Spann narrates an interplay of strong intellects with politics of social change in the 1920s and 1930s. Luccarelli and Wojtowicz cut an impressive swath through the entire scope of Mumford's thought and experience in the contexts of regionalism and architectural criticism. While all the books draw attention to men and women often forgotten but worth knowing about, Mumford is conspicuous for brilliance and charisma in the battle to reconcile urban growth with healthy environments and communities. His arsenal of values, shared by many supporters past and present, supplied articulate standards for change.
Dichotomy between luminance and disparity features at binocular fixations.

Analysis of the statistics of natural scene features at observers’ fixations can help us understand the mechanism of fixation selection and visual attention of the human vision system. Previous studies revealed that several low-level luminance features at fixations are statistically different from those at randomly selected locations. In our study, we conducted eye tracking experiments on naturalistic stereo images presented through a haploscope and found that fixated luminance contrast and luminance gradient are generally higher than randomly selected luminance contrast and luminance gradient, which agrees with previous literature, but the fixated disparity contrast and disparity gradient are generally lower than randomly selected disparity contrast and disparity gradient. We discuss the relevance of our findings in the context of the complexity of disparity calculations and the metabolic needs of disparity processing.
A hybrid approach of the standard clock method and event scheduling approach for general discrete event simulation

The standard clock (SC) method is an efficient approach for discrete event simulation. Its basic ideas are quite different from traditional approaches. SC has neither an event list nor event lifetimes. However, its applicability is limited to exponential distributions and a class of non-exponential distributions. In this paper we provide an effective approach to extend SC to all general distributions, while preserving the efficiency advantage of SC. Numerical testing shows that our approach can effectively accomplish this goal.
Getting Graduates to Come Home—Not So Easy

It is said that we live in the new era of the “brain exchange,” but in our view the old-style brain drain continues to a significant degree. With only modest success, countries, such as China, continue to try to get some of their scholars who have stayed abroad after completing advanced degrees to return home.
Should We Make Political Science More of a Science or More about Politics

To paraphrase slightly, I have been asked to focus on the apparent tensions between making genuinely scientific contributions by advancing knowledge in rigorous ways within specialized subfields, on the one hand, and addressing substantive political issues of general interest in accessible fashion, on the other. My view is that, though we should try to do both things, we should give priority to the latter—to helping both disciplinary and general public understandings of important substantive political issues become better informed and reasoned. To adopt this priority is still, I believe, to pursue the main tasks of political science as scientifically as possible; but it is true that this course involves significant tradeoffs.
Partitioning of K, U, and Th between sulfide and silicate liquids: Implications for radioactive heating of planetary cores

The possibility of heating of planetary cores by K radioactivity has been extensively discussed, as well as the possibility that K partitioning into the terrestrial core is the reason for the difference between the terrestrial and chondritic K/U. We had previously suggested that U and Th partitioning into FeFeS liquids was more important than K. Laboratory FeFeS liquid, silicate liquid partition coefficient measurements (D) for K, U, and Th were made to test this suggestion. For a basaltic liquid at 1450°C and 1.5 GPa, D_U is 0.013 and D_K is 0.0026; thus U partitioning into FeFeS liquids is 5 times greater than K partitioning under these conditions. There are problems with 1-atm experiments in that they do not appear to equilibrate or reverse. However, measurable U and Th partitioning into sulfide was nearly always observed, but K partitioning was normally not observed (D_K ≲ 10^(−4)). A typical value for D_U from a granitic silicate liquid at one atmosphere, 1150°C, and low f0_2 is about 0.02; D_(Th) is similar. At low f0_2 and higher temperature, experiments with basaltic liquids produce strong Ca and U partitioning into the sulfide liquid with D_U > 1. D_(Th) is less strongly affected. Because of the consistently low D_K/D_U, pressure effects near the core-mantle boundary would need to increase D_U by factors of ∼10^3 with much smaller increases in DU in order to have the terrestrial K and U abundances at chondritic levels. In addition, if radioactive heating is important for planetary cores, U and Th will be more important than K unless the lower mantle has K/U greater than 10 times chondritic or large changes in partition coefficients with conditions reverse the relative importance of K versus U and Th from our measurements.
Modeling and estimation of the spatial distribution of elevation error in high resolution DEMs from stereo-image processing

The authors examine the spatial variability of elevation error in high-resolution DEMs derived from stereo-image processing. DEM error models are developed by examining the correlation between various parameters and the observed DEM error. The DEM vertical errors are obtained from a database containing more than 51,000 points of known elevation. The error models are shown to have strong correlation with the magnitude of the random DEM vertical error. In addition, the models capture the full dynamic range of the observed error and are able to predict the overall error in four different high-resolution DEMs to within /spl plusmn/5%. Moreover, the final model is used to estimate the vertical error at every point in a DEM containing /spl sim/20 million elevations.
Radiation Risk in Nuclear Medicine

Given the central roles that anatomical and functional imaging now play in medical practice, there have been concerns about the increasing levels of radiation exposure and their potential hazards. Despite incomplete quantitative knowledge of the risks, it is prudent to think of radiation, even at low doses, as a potential, albeit weak, carcinogen. Thus, we are obliged to minimize its dose and optimize its benefits. Hopefully, time will clarify our estimates of the dangers. Until then, we should educate and assure our patients, their families, and colleagues that the risks have been taken into account and are well balanced by the benefits.
Characterization of a porcine intestinal epithelial cell line for influenza virus production

We have developed a porcine intestine epithelial cell line, designated SD-PJEC for the propagation of influenza viruses. The SD-PJEC cell line is a subclone of the IPEC-J2 cell line, which was originally derived from newborn piglet jejunum. Our results demonstrate that SD-PJEC is a cell line of epithelial origin that preferentially expresses receptors of oligosaccharides with Sia2-6Gal modification. This cell line is permissive to infection with human and swine influenza A viruses and some avian influenza viruses, but poorly support the growth of human-origin influenza B viruses. Propagation of swine-origin influenza viruses in these cells results in a rapid growth rate within the first 24 h post-infection and the titres ranged from 4 to 8 log10 TCID50 ml−1. The SD-PJEC cell line was further tested as a potential alternative cell line to Madin–Darby canine kidney (MDCK) cells in conjunction with 293T cells for rescue of swine-origin influenza viruses using the reverse genetics system. The recombinant viruses A/swine/North Carolina/18161/02 (H1N1) and A/swine/Texas/4199-2/98 (H3N2) were rescued with virus titres of 7 and 8.25 log10 TCID50 ml−1, respectively. The availability of this swine-specific cell line represents a more relevant substrate for studies and growth of swine-origin influenza viruses.