cssi/SciSciGPT-SciSciNet huggingface dataset:
Constant-Expansion Suffices for Compressed Sensing with Generative Priors

Generative neural networks have been empirically found very promising in providing effective structural priors for compressed sensing, since they can be trained to span low-dimensional data manifolds in high-dimensional signal spaces. Despite the non-convexity of the resulting optimization problem, it has also been shown theoretically that, for neural networks with random Gaussian weights, a signal in the range of the network can be efficiently, approximately recovered from a few noisy measurements. However, a major bottleneck of these theoretical guarantees is a network expansivity condition: that each layer of the neural network must be larger than the previous by a logarithmic factor. Our main contribution is to break this strong expansivity assumption, showing that constant expansivity suffices to get efficient recovery algorithms, besides it also being information-theoretically necessary. To overcome the theoretical bottleneck in existing approaches we prove a novel uniform concentration theorem for random functions that might not be Lipschitz but satisfy a relaxed notion which we call "pseudo-Lipschitzness." Using this theorem we can show that a matrix concentration inequality known as the Weight Distribution Condition (WDC), which was previously only known to hold for Gaussian matrices with logarithmic aspect ratio, in fact holds for constant aspect ratios too. Since the WDC is a fundamental matrix concentration inequality in the heart of all existing theoretical guarantees on this problem, our tighter bound immediately yields improvements in all known results in the literature on compressed sensing with deep generative priors, including one-bit recovery, phase retrieval, low-rank matrix recovery, and more.
Leadership Roles for School Counselors in Identifying and Supporting Twice-Exceptional (2E) Students:

School counselors have a variety of opportunities to serve as advocates and leaders for students identified as twice exceptional (2E). We explore these opportunities and discuss the academic and so...
A Low-Cost 1 Mbps Frequency Shift Keying Backscatter Receiver and Carrier Wave Generator System for Wireless Neural Recording

We present a low-cost, highly configurable receiver and external CW generator for frequency shift keying (FSK) based backscatter communication systems. The receiver uses a Nordic Semiconductor nRF24L01+ chip and an Arduino UNO to enable backscatter communication on any of 125 channels within the 2.4 GHz industrial, scientific, and medical (ISM) band. The receiver supports FSK modulation at up to 2.0 Mbps. Paired with an Arduino-based carrier generator, this system allows users to choose a backscatter uplink channel that minimizes interference from other 2.4 GHz devices (e.g. Wi-Fi and Bluetooth). As an example of a power-critical sensing application where backscatter can be used favorably, we present a wireless, digital neural recording system that leverages a 1.0 Mbps FSK backscatter uplink. The neural recording system has a 3 dB frequency response of 0.8 Hz to 220 Hz and uplinks up to 120 kbps of biopotential data at a sample rate of 500 Hz, with 16 bits of precision per sample. The packet uplink rate is 500 packets per second.
Precautionary Hoarding of Liquidity and Interbank Markets: Evidence from the Subprime Crisis

We study the liquidity demand of large settlement banks in the UK and its effect on the money markets before and during the subprime crisis of 2007-08. We find that the liquidity demand of large settlement banks experienced a 30% increase in the period immediately following August 9 2007, the day when money markets froze, igniting the crisis. Following this shift, liquidity demand had a precautionary nature in that it rose on days of high payment activity and for banks with greater credit risk. This caused over- night interbank rates to rise, an effect virtually absent in the precrisis period.
Paradoxical effect of cumulative stress exposure on information processing speed in Hispanics/Latinos with elevated heart rate variability

Chronic stress has a deleterious effect on prefrontal lobe functioning. Empirical evidence suggests elevated vagal tone, indexed by elevated heart rate variability (HRV), mitigates the effect of mental stress on frontal lobe function. Here, the mitigating effect of HRV on stress-related decrements in cognitive performance is assessed based on information processing speed (DSST), word fluency and verbal learning task performance. Artifact free electrocardiogram (ECG) data was analyzed from 1420 Hispanic/Latino adults from the Sociocultural Ancillary of the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). A 12-lead ECG was used to collect short-term recordings of the root mean square of successive differences in all normal R-peak to R-peak intervals (RMSSD) and the change between adjacent beats and the standard deviation of those intervals (SDNN) as indices of total HRV. As predicted, an interaction emerged for HRV and stress on the task presumed to require the greatest prefrontal lobe involvement, i.e., the DSST. After accounting for sociodemographic factors, chronic stress was associated with better DSST performance amongst individuals at higher quartile of SDNN, but not RMSSD. The paradoxical effect for greater stress exposure on DSST performance may in part be explained by increased speed of information processing and decision making often reported in high-stress cohorts. The nature of this interaction highlights the importance of examining the relationship between stress and cognition across a spectrum of vagal tone.
Hyperzyklische gruppen

Definition: (a)G is called hypercyclic «iff each epimorphic imageH≠1 ofG possesses a cyclic normal subgroupA≠1». (b)G is called hypercentral «iff each epimorphic imageH≠1 ofG hasZ(H)≠1». (c) the set of prime numbers which divide the orders of the torsion elements (≠1) ofG is called «the characteristic ofG». Baer has shown that each hypercyclic groupG is a subdirect product of hypercyclic groups of finite characteristic. In this note we will characterize hypercentral groups by abelian torsion groups of finite exponent.
A Bayesian Model to Analyze the Association of Rheumatoid Arthritis With Risk Factors and Their Interactions

Rheumatoid arthritis (RA) is a chronic autoimmune disorder that commonly manifests as destructive joint inflammation but also affects multiple other organ systems. The pathogenesis of RA is complex where a variety of factors including comorbidities, demographic, and socioeconomic variables are known to associate with RA and influence the progress of the disease. In this work, we used a Bayesian logistic regression model to quantitatively assess how these factors influence the risk of RA, individually and through their interactions. Using cross-sectional data from the National Health and Nutrition Examination Survey (NHANES), a set of 11 well-known RA risk factors such as age, gender, ethnicity, body mass index (BMI), and depression were selected to predict RA. We considered up to third-order interactions between the risk factors and implemented factor analysis of mixed data (FAMD) to account for both the continuous and categorical natures of these variables. The model was further optimized over the area under the receiver operating characteristic curve (AUC) using a genetic algorithm (GA) with the optimal predictive model having a smoothed AUC of 0.826 (95% CI: 0.801-0.850) on a validation dataset and 0.805 (95% CI: 0.781-0.829) on a holdout test dataset. Apart from corroborating the influence of individual risk factors on RA, our model identified a strong association of RA with multiple second- and third-order interactions, many of which involve age or BMI as one of the factors. This observation suggests a potential role of risk-factor interactions in RA disease mechanism. Furthermore, our findings on the contribution of RA risk factors and their interactions to disease prediction could be useful in developing strategies for early diagnosis of RA.
Target Coverage, Organ at Risk Metrics, and Tumor Control for Metastases to the Pancreas Treated With Adaptive MR-Guided Stereotactic Body Radiation Therapy.

Purpose/objective(s) Metastases to the pancreas (MPs) are difficult to treat with radiation therapy (RT) due to respiratory and bowel motion and proximity to critical organs at risk (OARs). Magnetic resonance-guided stereotactic body radiation therapy (MRgSBRT) may improve tumor coverage and OAR sparing through motion control with breath hold gating and continuous MR imaging during treatment, and the option for daily online adaptive replanning (ARP) to account for changes in tumor and/or OAR position. We evaluated the need for online adaptive MRgSBRT and its effect on target coverage, OAR metrics, and tumor control in patients with MPs. Materials/methods In this IRB-approved retrospective study, we reviewed the records of patients with MPs treated with MRgSBRT between July 2019 and January 2021. Patients were identified from a prospectively maintained database. Data were collected regarding dose to targets and OARs, use and rationale for ARP, toxicity, and outcomes. Treatment response was defined as a decrease in size of the treated MP. Local failures were defined as recurrences within the RT field. Descriptive statistics were used. Results We identified 8 MPs in 6 patients. Median age was 70 years (range, 61-88). Patients had oligoprogressive or oligometastatic renal cell carcinoma (n = 3), carcinoid (n = 1), hepatocellular carcinoma (n = 1), and lung adenocarcinoma (n = 1). The median time from diagnosis to development of metastatic disease was 17 months (range, 0-105 months) and to treatment of the MP was 36 months (range, 7-230 months). All patients received 40 Gy in 5 fractions with breath hold technique. The median GTV was 8.5 cc (range, 2.2-132.8 cc) and PTV was 27.7 cc (range, 8.3-175.7 cc). 35/40 (87%) fractions required ARP, necessary to meet stomach and duodenal metrics in 11 (27%) and 16 (40%) fractions, respectively. The mean stomach, duodenal, and PTV metrics before and after ARP are reported in Table 1. On average, ARP increased the PTV coverage by 4.9% and decreased the stomach V33, stomach V35, and duodenum V33 by 0.61 cc, 0.31 cc, and 1.10 cc, respectively. At a median follow-up of 5.0 months, 6/8 (75%) lesions had a partial response. There were no local failures. There was one distant failure 27 days after treatment. One patient developed a grade 2 pyloric ulcer which resolved with medical management. There were no other ≥ grade 2 toxicities. Conclusion In this study, ARP was necessary in most MRgSBRT treatments to MPs. Adaptive MRgSBRT improved PTV coverage and OAR metrics, and it provided high rates of tumor control with minimal toxicity. Further study in larger patient populations and in peripancreatic metastases is needed.
How (not) to Shed Light on the Experiment in Economics.

A review essay on Philippe Fontaine and Robert Leonard (eds), The Experiment in the History of Economics, London and New York, Routledge, 2005, pp. xiii+158.
Design and characterization of diagonal horn antennas using UCLA bi-polar near-field measurement and imaging facilities

A current study at UCLA deals with the design of various horn antennas and feeds for reflector antennas. In order to enhance the radiation performance of typical pyramidal horns, the application of a diagonal horn has been considered. The radiation pattern of this horn antenna shows almost perfect circular symmetry so that the 3 dB, 10 dB and 20 dB beam widths are very closely equal. This is true not only for the 0/spl deg/- and 90/spl deg/-cut but also in the 45/spl deg/- and 135/spl deg/-plane. All cross-sections through the diagonal horn antenna are square, starting from the feeding square waveguide to the aperture. For small flare angles the mode of propagation within the horn is principally such that the electric vector is parallel to one of the diagonals. Since orthogonal polarized beams will have the same far-field characteristic, the diagonal horn is an interesting candidate for use by itself or for reflector antennas. The emphasis of this article is on the investigation for some of the unique features of the diagonal horn by evaluating the images of its aperture field using the measured bi-polar near-field data.
Science with Herschel: Results from the HERITAGE project

The Herschel Space Observatory completed its last observation on 2013 April 29 after completing 35000 astronomical observations resulting in numerous discoveries. In this review, we describe the capabilities and general scope of the Herschel mission. In particular, we review the science results from one of the open time key programs, the HERschel Inventory of The Agents of Galaxy Evolution (HERITAGE) in the Magellanic Clouds. The HERITAGE project mapped the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) at 100, 160, 250, 350, and 500 μm using the SPIRE/PACS parallel mode. The total global fluxes for the LMC and SMC agree with measurements by other missions, including Planck. The HERITAGE maps of the LMC and SMC are dominated by the ISM dust emission and bear most resemblance to the tracers of ISM gas rather than the stellar content of the galaxies. The overriding science goal of HER-ITAGE is to study the life cycle of matter as traced by dust in the LMC and SMC. The far-infrared and submillimeter emission is an effective tracer of the interstellar medium (ISM) dust, the most deeply embedded young stellar objects (YSOs) and the dust ejected by the most massive stars which are discussed briefly in this review. The HERITAGE team has delivered the maps and source catalogs created for each of the 5 bands to the Herschel Science Center archive which will hold the legacy of Herschel. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Contrast invariance of orientation tuning in cat primary visual cortex neurons depends on stimulus size

Key points The process of orientation tuning is an important and well-characterized feature of neurons in primary visual cortex. The combination of ascending and descending circuits involved is not only relevant to understanding visual processing but the function of neocortex in general. The classic feed-forward model of orientation tuning predicts a broadening effect due to increasing contrast; yet, experimental results consistently report contrast invariance. We show here that contrast invariance actually depends on stimulus size such that large stimuli extending beyond the neuron's receptive field engage circuits that promote invariance, whereas optimally sized, smaller stimuli result in contrast variance that is more in line with the classical orientation tuning model. These results illustrate the importance of optimizing stimulus parameters to best reflect the sensory pathways under study and provide new clues about different circuits that may be involved in variant and invariant response properties. Abstract Selective response to stimulus orientation is a key feature of neurons in primary visual cortex, yet the underlying mechanisms generating orientation tuning are not fully understood. The combination of feed-forward and cortical mechanisms involved is not only relevant to understanding visual processing but the function of neocortex in general. The classic feed-forward model predicts that orientation tuning should broaden considerably with increasing contrast; however, experimental results consistently report contrast invariance. We show here, in primary visual cortex of anaesthetized cats under neuromuscular blockade, that contrast invariance occurs when visual stimuli are large enough to include the extraclassical surround (ECS), which is likely to involve circuits of suppression that may not be entirely feed-forward in origin. On the other hand, when stimulus size is optimized to the classical receptive field of each neuron, the population average shows a statistically significant 40% increase in tuning width at high contrast, demonstrating that contrast variance of orientation tuning can occur. Conversely, our results also suggest that the phenomenon of contrast invariance relies in part on the presence of the ECS. Moreover, these results illustrate the importance of optimizing stimulus parameters to best reflect the neural pathways under study.
Quantum Hall effect in Coulomb drag: Interlayer friction in strong magnetic fields.

We study the Coulomb drag between two spatially separated electron systems in a strong magnetic field, one of which exhibits the quantum Hall effect. At a fixed temperature, the drag mimics the behavior of $\sigma_{xx}$ in the quantum Hall system, in that it is sharply peaked near the transitions between neighboring plateaux. We assess the impact of critical fluctuations near the transitions, and find that the low temperature behavior of the drag measures an exponent $\eta$ that characterizes anomalous low frequency dissipation; the latter is believed to be present following the work of Chalker.
Latin American ADR performance

Purpose – The purpose of this study is to determine whether Latin American ADRs provided US investors with international diversification benefits as determined by comparing excess returns from issues listed in the 1990s to those listed in the 2000s. A further sample breakdown compares IPO returns to SEO returns. Design/methodology/approach – Standard ADR return methodology used in many previous studies is utilized to compute and test excess returns. This methodology is the same as the standard methodology used in IPO studies. Findings – The total Latin American ADR sample returned roughly the same as the S & P 500 index for the three year holding period; however, those issued before 2000 underperformed the index by nearly 19 percent while those listed after January 1, 2000 outperformed the index by nearly 58 percent. The excess returns of IPOs were nearly 50 percent less than SEOs when compared to the index. Also, both IPOs and SEOs listed after the new millennium began drastically outperformed those list...
Protection from Bilirubin Nephropathy in Jaundiced Gunn Rats

The inclusion of 2% agar (w/w) in the diet of homozygous jaundiced (jj) rats resulted in greater fecal excretions of bile pigment, as measured by bilirubin and urobilin. Associated with the agar diet feedings, the concentrations of bilirubin in serum, adipose tissue, and renal medullae were less than in littermate animals fed the control diet. The renal free water clearance ( C H 2 O ) in jj animals was significantly lower by 5 months of age when compared with nonjaundiced (Jj) normal animals. The C H 2 O in jj animals raised on the agar diet did not significantly differ from normal Jj animals at 5 months of age and was greater than the littermate jj animals raised on the standard diet. The results suggest that the nephropathy of jj rats is secondary to the accumulation of bilirubin in the renal papillae rather than a genetic deficiency of medullary function.
Anthrolysin O and fermentation products mediate the toxicity of Bacillus anthracis to lung epithelial cells under microaerobic conditions

Bacillus anthracis generates virulence factors such as lethal and edema toxins, capsule, and hemolytic proteins under conditions of reduced oxygenation. Here, we report on the acute cytotoxicity of culture supernatants (Sups) of six nonencapsulated B. anthracis strains grown till the stationary phase under static microaerobic conditions. Human small airway epithelial, umbilical vein endothelial, Caco-2, and Hep-G2 cells were found to be susceptible. Sups displayed a reduction of pH to 5.3–5.5, indicating the onset of acid anaerobic fermentation; however, low pH itself was not a major factor of toxicity. The pore-forming hemolysin, anthrolysin O (ALO), contributed to the toxicity in a concentration-dependent manner. Its effect was found to be synergistic with a metabolic product of B. anthracis, succinic acid. Cells exposed to Sups demonstrated cytoplasmic membrane blebbing, increased permeability, loss of ATP, mitochondrial membrane potential collapse, and arrest of cell respiration. The toxicity was reduced by inhibition of ALO by cholesterol, decomposition of reactive oxygen species, and inhibition of mitochondrial succinate dehydrogenase. Cell death appears to be caused by an acute primary membrane permeabilization by ALO, followed by a burst of reactive radicals from the mitochondria fuelled by the succinate, which is generated by bacteria in the hypoxic environment. This mechanism of metabolic toxicity is relevant to the late-stage conditions of hypoxia and acidosis found in anthrax patients and might operate at anatomical locations of the host deprived from oxygen supply.
Poaching risks in community-based natural resource management

Poaching can disrupt wildlife-management efforts in community-based natural resource management systems. Monitoring, estimating, and acquiring data on poaching is difficult. We used local-stakeholder knowledge and poaching records to rank and map the risk of poaching incidents in 2 areas where natural resources are managed by community members in Caprivi, Namibia. We mapped local stakeholder perceptions of the risk of poaching, risk of wildlife damage to livelihoods, and wildlife distribution and compared these maps with spatially explicit records of poaching events. Recorded poaching events and stakeholder perceptions of where poaching occurred were not spatially correlated. However, the locations of documented poaching events were spatially correlated with areas that stakeholders perceived wildlife as a threat to their livelihoods. This result suggests poaching occurred in response to wildlife damage occurred. Local stakeholders thought that wildlife populations were at high risk of being poached and that poaching occurred where there was abundant wildlife. These findings suggest stakeholders were concerned about wildlife resources in their community and indicate a need for integrated and continued monitoring of poaching activities and further interventions at the wildlife-agricultural interface. Involving stakeholders in the assessment of poaching risks promotes their participation in local conservation efforts, a central tenet of community-based management. We considered stakeholders poaching informants, rather than suspects, and our technique was spatially explicit. Different strategies to reduce poaching are likely needed in different areas. For example, interventions that reduce human-wildlife conflict may be required in residential areas, and increased and targeted patrolling may be required in more remote areas. Stakeholder-generated maps of human-wildlife interactions may be a valuable enforcement and intervention support tool.
Baroreceptor sensitivity response to phase IV of the Valsalva maneuver in spinal cord injury

Due to the increased prevalence of ischemic heart disease and hypertension reported in individuals with chronic spinal cord injury (SCI), we investigated whether subjects with low level SCI (paraplegia), without apparent evidence of coronary artery disease, exhibit normal baroreceptor and autonomic function. Eighteen males participated in this study: seven normotensive with paraplegia, five hypertensive with paraplegia and six normotensive non-SCI controls. The Valsalva maneuver was performed by maintaining a pressure of 40 mmHg over 15 s and R-R intervals (RRI) and arterial blood pressure were measured continuously. Phase IV of the Valsalva maneuver was determined by linear regression analysis between RRI and systolic pressure, with a final slope calculated. The power spectra for RRI and blood pressure variability parameters were also analyzed, in addition to the index alpha, a frequency domain estimate of the overall gain in baroreceptor control of the RRI-arterial blood pressure. The normotensive subjects with paraplegia were found to have an impaired baroreceptor response when compared with age-matched, non-SCI controls. In addition, the levels of both the low frequency and high frequency spectral components of RRI and the index alpha were reduced in these individuals at rest. These cumulative findings strongly suggest that the integrity of the sinoaortic baroreceptors, as well as efferent parasympathetic function, may be compromised in otherwise apparently healthy individuals with chronic paraplegia.
Income and Residential Location: Muth Revisited

In Cities and Housing, Muth modeled residential location by income in terms of the conflicting desires for a low price of housing and access to CBD. This paper expands Muth's model to include in the location decision locational amenities other than access. Land values around Chicago are then used to estimate the income elasticities of the bids for access and five other amenities. The results indicate that the value of access may rise more rapidly with income than Muth expected and that, in the absence of other amenities and a durable housing stock, higher income residents would live closer to the CBD than low-income residents. Furthermore, other amenities may be important determinants of residential location patterns.
Correlation of polymeric compatibilizer structure to its impact on the morphology and function of P3HT:PCBM bulk heterojunctions

The impact of various polymeric compatibilizers, including end-functionalized P3HTs and diblock copolymers containing P3HT, on the structure and function of poly(3-hexylthiophene) (P3HT):[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) bulk heterojunctions is presented. Careful analyses of small angle neutron scattering curves provide a measure of the miscibility of PCBM in P3HT, the average PCBM domain size, and the interfacial area between PCBM and the P3HT-rich phase in the uncompatibilized and compatibilized systems. Differential scanning calorimetry (DSC) also provides information regarding the changes in the crystallinity of P3HT due to the presence of the compatibilizer. Results show that most compatibilizers cause the domain sizes to decrease and the P3HT crystallinity to increase; however, some cause an increase in domain size, suggesting that they are not effective interfacial modifiers. The correlation of morphology with photovoltaic activity shows that the decreased domain size, increased crystallinity and increased interfacial area do not always result in improved power conversion efficiency (PCE). It appears that the introduction of an insulating molecule at the PCBM:P3HT interface as a compatibilizer results in a decrease in PCE. Thus, the presence of the compatibilizer at this interface dominates the photovoltaic activity, rather than the morphological control.
The production of progesterone, androgens, and estrogens by granulosa cells, thecal tissue, and stromal tissue from human ovaries in vitro.

The concentrations of steroids in antral fluid, the number of granulosa cells, the status of the oocyte, and the diameter of each follicle were determined in human ovaries so that follicles at each stage of the menstrual cycle could be classified as large (>8 mm diameter) or small (<8 mm diameter) and healthy or atretic. The granulosa cells and thecal-enriched tissue from each follicle and the stromal tissue from each ovary were cultured for 6 days in vitro. The amounts of progesterone (P), androstenedione (Δ4), testosterone, dihydrotestosterone, es-trone, and estradiol (E2) generated by the different tissues were measured on days 0, 2, 4, and 6 of culture. It was found that granulosa cells, thecal tissue, and stromal tissue all have the biosynthetic capacity to produce (P, Δ4 (,)tes -tosterone, dihydrotestosterone, estrone, and (E2No individual steroid-secreting compartment of the ovaries studied, whether part of the follicle or of the stroma, had the exclusive capability of producing any of the above-na...
Sugaring out: A new method for removal of acetonitrile from preparative RP-HPLC eluent for protein purification

Abstract Reverse phase-high pressure liquid chromatography (RP-HPLC) with an acetonitrile–water mixture as the eluent is widely used for purification of proteins. The separation of acetonitrile (ACN) in RP-HPLC eluent is important for protein recovery. Cooling below subzero temperature and salting out have been used to remove ACN, each with its limitations. In this work we have explored the use of sugaring-out, a new phase separation method developed at University of Illinois for the separation of ACN from a simulated preparative RP-HPLC effluent. The effect of glucose concentration, temperature, and initial amount of ACN in the effluent on phase separation was investigated. Results showed that a good phase separation can be achieved at near room temperature (18 °C). With the optimized conditions, we found that more than 60% (w/w) of ACN was removed and more than 95% (w/w) of water-soluble proteins (bovine serum albumin, trypsin, and pepsin) were recovered.
TENANCY ARRANGEMENTS USED BY LOUISIANA CRAWFISH PRODUCERS

Land tenancy arrangements vary widely in the U.S. crawfish industry, including full ownership by the crawfish producer, cash leases, share leases, and combination cash-share leases. This study examines the array of tenancy arrangements available and analyzes the types of farmers selecting each using a multinomial logit model. Choice of tenancy arrangement varies according to a number of traditional factors, such as farm size, experience, specialization, and production system. The influence of production system on land tenancy selection is of particular interest. Crawfish-rice double-crop producers tend to own all of their crawfish land, while those farming under rotational systems with crawfish and field crops tend to select combination cash-share leases. Shares, rental rates, and percentages of pumping cost paid by the landlord vary widely.
Some algebraic identities for the α-permanent

Abstract The permanent of a matrix is a linear combination of determinants of block diagonal matrices which are simple functions of the original matrix. To prove this, we first show a more general identity involving α-permanents: for arbitrary complex numbers α and β, we show that the α-permanent of any matrix can be expressed as a linear combination of β-permanents of related matrices. Some other identities for the α-permanent of sums and products of matrices are shown, as well as a relationship between the α-permanent and general immanants. We conclude with some discussion and a conjecture for the computational complexity of the α-permanent, and provide some numerical illustrations.
Higher locomotor response to cocaine in female (vs. male) rats selectively bred for high (HiS) and low (LoS) saccharin intake

Abstract Rats selectively bred for high saccharin consumption (HiS) self-administer more oral ethanol and i.v. cocaine than those selectively bred for low saccharin consumption (LoS). Male and female drug-seeking-prone (HiS) and -resistant (LoS) rats were used in the present experiment to test the prediction that cocaine-induced locomotor activity and sensitization varied with sex and their selective breeding status (HiS and LoS). All rats were intermittently exposed over 2 weeks to pairs of sequential saline and cocaine injections, separated by 45 min. The first 5 pairs of injections, each separated by 2–3 days (10–12 days total), were given to examine the development of cocaine-induced locomotor activity and the development of locomotor sensitization, which was determined by comparing the effects of cocaine injection 1 with injection 6 (given 2 weeks after the 5 pairs of intermittent injections). Results indicated that after the first injection pair (saline, cocaine) the HiS and LoS groups did not differ (saline vs. cocaine) in locomotor activity; however, after cocaine injection pairs 1, 5, and 6, HiS females were more active than HiS males and LoS females. There were also significant phenotype differences (HiS > LoS) in locomotor activity after cocaine injections 5 and 6. There was a weak sensitization effect in cocaine-induced locomotor activity in HiS females after cocaine injection 5 (compared to 1); however it was not present after injection 6 or in other groups. The lack of a strong sensitization effect under these temporal and dose conditions was inconsistent with previous reports. However, the results showing HiS > LoS and females > males on cocaine-induced activity measures are consistent with several measures of cocaine-seeking behavior (acquisition, maintenance, escalation, extinction, and reinstatement), and they suggest that cocaine-induced locomotor activity and sensitization are behavioral markers of drug-seeking phenotypes.
Quantitative prediction of radio frequency induced local heating derived from measured magnetic field maps in magnetic resonance imaging: A phantom validation at 7 T

Electrical Properties Tomography (EPT) technique utilizes measurable radio frequency (RF) coil induced magnetic fields (B1 fields) in a Magnetic Resonance Imaging (MRI) system to quantitatively reconstruct the local electrical properties (EP) of biological tissues. Information derived from the same data set, e.g., complex numbers of B1 distribution towards electric field calculation, can be used to estimate, on a subject-specific basis, local Specific Absorption Rate (SAR). SAR plays a significant role in RF pulse design for high-field MRI applications, where maximum local tissue heating remains one of the most constraining limits. The purpose of the present work is to investigate the feasibility of such B1-based local SAR estimation, expanding on previously proposed EPT approaches. To this end, B1 calibration was obtained in a gelatin phantom at 7 T with a multi-channel transmit coil, under a particular multi-channel B1-shim setting (B1-shim I). Using this unique set of B1 calibration, local SAR distribution was subsequently predicted for B1-shim I, as well as for another B1-shim setting (B1-shim II), considering a specific set of parameter for a heating MRI protocol consisting of RF pulses plaid at 1% duty cycle. Local SAR results, which could not be directly measured with MRI, were subsequently converted into temperature change which in turn were validated against temperature changes measured by MRI Thermometry based on the proton chemical shift.
Climatic Conditions and the Risk of Testicular Torsion in Adolescent Males

Purpose: The risk factors for acute testicular torsion are poorly understood. Environmental factors have been implicated by some authors and discredited by others. The only previous known study in the United States did not demonstrate any seasonal correlation, although the study was done in a warmer climate. We sought to determine if environmental factors impact the incidence of testicular torsion in our temperate climate conditions with a large differential between the warmest and coldest temperatures.Materials and Methods: We retrospectively studied patients who were diagnosed with testicular torsion between January 1997 and December 2006. Data regarding weather conditions were collected, including season, temperature, humidity and atmospheric pressure at the time of onset of symptoms. Spearman’s rank correlation was performed to assess the relationship between atmospheric temperature and frequency of testicular torsion. Multivariate analysis was performed to analyze the effect of covariables.Results: A...
Probing quark-gluon correlation functions

We review the applicability of the QCD factorization theorem to multiple scattering in deeply inelastic lepton-nucleus scattering. We show why an A{sup 1/3}-type nuclear enhancement can be calculated consistently in perturbative QCD. We derive the transverse momentum broadening of the leading pions in deeply inelastic lepton-nucleus collisions. We argue that the measurement of such transverse momentum broadening can provide direct information on the multiple-parton correlation functions inside a nucleus. We also estimate the numerical values of the broadening at different values of x{sub B} and Q{sup 2}. (c) 2000 The American Physical Society.
Can one ADM quantize relativistic bosonicstrings and membranes

The standard methods for quantizing relativistic strings diverge significantly from the Dirac-Wheeler-DeWitt program for quantization of generally covariant systems and one wonders whether the latter could be successfully implemented as an alternative to the former. As a first step in this direction, we consider the possibility of quantizing strings (and also relativistic membranes) via a partially gauge-fixed ADM (Arnowitt, Deser and Misner) formulation of the reduced field equations for these systems. By exploiting some (Euclidean signature) Hamilton-Jacobi techniques that Mike Ryan and I had developed previously for the quantization of Bianchi IX cosmological models, I show how to construct Diff(S1)-invariant (or Diff(Σ)-invariant in the case of membranes) ground state wave functionals for the cases of co-dimension one strings and membranes embedded in Minkowski spacetime. I also show that the reduced Hamiltonian density operators for these systems weakly commute when applied to physical (i.e. Diff(S1) or Diff(Σ)-invariant) states. While many open questions remain, these preliminary results seem to encourage further research along the same lines.
Refraction by a spherical nematic bubble.

A formalism is developed to study refraction by a spherical nematic bubble. It is applicable to bubbles that are larger than light wavelengths, but smaller than the dimensions for excitation of director-fluctuation-induced scattering. The technique yields a nonlinear differential equation and an associated integral which govern the trajectory of a ray inside a nematic region for an arbitrary director configuration. Explicit solutions are provided for five simple interior arrangements---isotropic, onion skin, radial star, horizontal (bottle brush), and vertical. It is then demonstrated that for extraordinary-ordinary refractive-index difference small compared to either, interfacial refraction at the bubble surface is the dominant contribution; deviations from a rectilinear path are small. When ranked in terms of decreasing scattering effectiveness, the sequence is horizontal, onion, isotropic, radial, and vertical if the light is linearly polarized and coupling optimally to the extraordinary index component; for unpolarized incoherent light the order becomes isotropic, horizontal, onion, radial, and vertical.
Dihydrofolate reductase protein inhibits its own translation by binding to dihydrofolate reductase mRNA sequences within the coding region.

Previous studies suggest that dihydrofolate reductase (DHFR) regulates its own translation. Moreover, intracellular levels of DHFR protein increase following exposure to the antifolate methotrexate (MTX), suggesting that MTX may release the translational inhibition mediated by DHFR [Chu et al. (1993) Biochemistry 32, 4756−4760; Ercikan et al. (1993) Adv. Exp. Med. Biol. 338, 537−540]. To further investigate the role of DHFR in translational autoregulation, we have considered the possibility that DHFR directly contacts its cognate mRNA. Binding studies using a series of truncated DHFR mRNAs as probes localized the DHFR/RNA interaction to a 100-base-pair region containing two putative stem−loop structures; initial studies indicated that both of these loop structures are involved in protein binding. Moreover, the binding of MTX to DHFR prevents interaction of the protein with its cognate mRNA, thereby relieving translational autoregulation.
Early experiences scaling VMD molecular visualization and analysis jobs on blue waters

Petascale molecular dynamics simulations provide a powerful tool for probing the dynamics of cellular processes at atomic and nanosecond resolution not achievable by experimental methods alone. Extraction of details about the dynamics of biomolecules from terabytes of simulation output requires powerful user-extensible molecular analysis and visualization tools. Petascale simulation trajectories are so large that it is now necessary to perform many analysis and visualization tasks formerly handled by off-site computational facilities in-place on the supercomputer itself. We report ongoing progress on porting, tuning, and scaling up the popular molecular visualization and analysis program VMD on the NSF Blue Waters petascale supercomputer. We describe key achievements including algorithmic and memory efficiency improvements, hand-vectorization of key CPU algorithms, new and improved GPU analysis and visualization algorithms, and parallel I/O performance results. We evaluate the performance of VMD for user-developed analysis scripts with the TIMELINE trajectory analysis tool in VMD. Finally, we describe the unique capabilities provided by the Cray XK7 GPU-accelerated compute partition of Blue Waters.
Potential adverse effects of spinal immobilization in children.

AbstractObjective. The purpose of our study was to describe potential adverse effects associated with spinal immobilization following trauma among children. Methods. We conducted a prospective cohort study of children presenting to the emergency department (ED) for evaluation following trauma over a 13-month period. Children were eligible if they underwent spinal immobilization prior to physician evaluation or if they met the American College of Surgeons (ACS) guidelines for spinal immobilization but were not immobilized. We compared children who were immobilized with those who were not immobilized for self-reported pain, use of radiography to evaluate the cervical spine, ED length of stay, and ED disposition. We also report the characteristics of the cohort. Results. One hundred seventy-three spine-immobilized children and 112 children who met ACS criteria but were not immobilized were enrolled. There were differences between the two study groups, which included age, mechanism of injury, and proportion t...
Dimensional deconstruction and Wess-Zumino-Witten terms

A new technique is developed for the derivation of the Wess-Zumino-Witten (WZW) terms of gauged chiral Lagrangians. We start in $D=5$ with a pure (mesonless) Yang-Mills theory, which includes relevant gauge field Chern-Simons terms. The theory is then compactified, and the effective $D=4$ Lagrangian is derived using lattice techniques, or ``deconstruction,'' where pseudoscalar mesons arise from the lattice Wilson links. This yields the WZW term with the correct Witten coefficient by way of a simple heuristic argument. We discover a novel WZW term for singlet currents, that yields the full Goldstone-Wilczek current, and a $U(1)$ axial current for the Skyrmion, with the appropriate anomaly structures. A more detailed analysis is presented of the dimensional compactification of Yang-Mills in $D=5$ into a gauged chiral Lagrangian in $D=4$, heeding the consistency of the $D=4$ and $D=5$ Bianchi identities. These dictate a novel covariant derivative structure in the $D=4$ gauge theory, yielding a field strength modified by the addition of commutators of chiral currents. The Chern-Simons term of the pure $D=5$ Yang-Mills theory then devolves into the correct form of the Wess-Zumino-Witten term with an index (the analogue of ${N}_{\mathrm{c}\mathrm{o}\mathrm{l}\mathrm{o}\mathrm{r}\mathrm{s}}=3$) of $N=D=5$. The theory also has a Skyrme term with a fixed coefficient.
Elimination of two level fluctuators in superconducting quantum bits by an epitaxial tunnel barrier

Quantum computing based on Josephson junction technology is considered promising due to its scalable architecture. However, decoherence is a major obstacle. Here, we report evidence for improved Josephson quantum bits (qubits) using a single-crystal ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ tunnel barrier. We have found an $\ensuremath{\sim}$80% reduction in the density of the spectral splittings that indicate the existence of two-level fluctators (TLFs) in amorphous tunnel barriers. The residual $\ensuremath{\sim}20%$ TLFs can be attributed to interfacial effects that may be further reduced by different electrode materials. These results show that decoherence sources in the tunnel barrier of Josephson qubits can be identified and eliminated.
Slater-Koster parametrization for Si and the ideal-vacancy calculation

A Slater-Koster Hamiltonian for Si is constructed using four (one $s$ and three $p$) orthogonal orbitals per site. This Hamiltonian reproduces reasonably accurately the empirical pseudopotential band structure not only for the valence but for the conduction band as well. It also determines correctly the position of the bound level of an unreconstructed vacancy demonstrating thus that the effects of electronic self-consistency are minor.
Proximal tubular adenoma of kidney

Abstract Fourteen cases of benign tumor, radiographically and angiographically indistinguishable from a renal malignancy, are presented. Clinically, these cases are distinguished by the absence of symptoms referable to the lesion and pathologically differentiated both grossly and microscopically. Our recent experience with 5 cases suggests the possibility that its incidence is increasing and may be related to some specific epidemiologic etiology.
Reply to ``Comment on `Single-particle Green functions in exactly solvable models of Bose and Fermi liquids' ''

It is shown that the sea-boson model given in G.S. Setlur and Y.C. Chang, Phys. Rev. B 57, 15 144 (1998), is capable of reproducing the four-point correlation functions of fermion operators within the random-phase approximation, although an explicit expression for the sea-boson operator is still lacking.
Stress Fiber Organization and Dynamics in Cells Adhered to Substrates of Varying Stiffness

AbstractCellular morphology, locomotion and division are closely related to the stiffness of the substrates onto which the cells are cultured. The stiffness of cultured cells typically increases with the stiffness of the substrate. This increase correlates with increased contractility and the development of a meshwork of parallel and cross-linked stress fibers along the contacting surface. Many questions remain regarding the mechanisms that underlie cell-level cytoskeletal remodeling during mechanosensing. To better quantify the morphology and dynamics of the actomyosin cytoskeleton as a function of substrate stiffness, we used confocal microscopy to image cultured HeLa cells that stably express myosin regulatory light chain tagged with GFP (MRLC-GFP). We cultured cells on poly-acrylamide substrates coated with collagen I, with stiffness ranging from 0.4 kPa to 60 kPa. We used image segmentation methods to measure stress fiber and cortical myosin distributions in static 3D images. Time-lapse recordings show a connected stress fiber meshwork that evolves through new stress fiber formation on the cell periphery, contractile activity, and stress fiber merging and splitting over times of order hours. Quantitative analysis is suggestive of kinetic models that explore how different cortical myosin remodeling kinetics may contribute to different cell shape and rigidity depending on substrate stiffness.
The Effect of Substrate Misorientation on the Evolution of Surface Morphology in Epitaxially Grown CaF2/Si(111) Heterostructures

We have studied the effect of substrate misorientation on the evolution of surface morphology in lattice-mismatched heterostructures for molecular beam epitaxial growth of a thin insulator (CaF 2 ) on vicinal Si(111) surfaces with in-situ reflection high energy electron diffraction (RHEED) and ex-situ atomic force microscopy (AFM). At a substrate temperature of 770 °C, CaF 2 growth is initiated by the formation of a reacted CaF layer followed by the complete overgrowth of an additional CaF 2 monolayer (ml). However, CaF 2 growth beyond these two ml depends on the degree of miscut of the Si substrate. On Si substrates tilted toward the [112] by a miscut angle ≥ 0.5°, the atomic step edges on the Si surface bunch together forming flat terraces that are ∼200 nm wide. In this case, the CaF 2 growth beyond 2 ml proceeds by the nucleation and lateral propagation of thick CaF 2 islands (whose height is determined by the step bunches) along the bunched step edges to eventually form a complete overlayer. For CaF 2 films grown on substrates with a miscut angle 2 layer remains relatively uniform without the formation of thick islands. With further deposition, evidence for a dense network of misfit dislocations is observed on the surface of the CaF 2 film.