cssi/SciSciGPT-SciSciNet huggingface dataset:
On abelian $$\ell $$ ℓ -towers of multigraphs

We study how the $$\ell $$ -adic valuation of the number of spanning trees varies in regular abelian $$\ell $$ -towers of multigraphs. We show that for an infinite family of regular abelian $$\ell $$ -towers of bouquets, the $$\ell $$ -adic valuation of the number of spanning trees behaves similarly to the $$\ell $$ -adic valuation of the class numbers in $${\mathbb {Z}}_{\ell }$$ -extensions of number fields.
Traumatic Injury Under COVID-19 Stay-at-home Advisory: Experience of a New England Trauma Center.

ABSTRACT Background With the onset of the COVID-19 pandemic and subsequent widespread stay-at-home advisories throughout early 2020, hospitals have noticed a decrease in illnesses unrelated to COVID-19. However, the impact on traumatic injury is relatively unknown. This study aims to characterize patterns of trauma during the COVID-19 pandemic at a Level I Trauma Center. Materials & methods A retrospective review was performed of adult trauma patients from March to June, in the years 2018 through 2020. Primary outcome was the number of trauma activations (volume). Secondary outcomes included activation level, mechanism of injury, mortality rate, and length of stay, and other demographic background. Trauma patterns of the 2018 and 2019 periods were combined as historical control, and compared to patterns of the biweekly-matched period of 2020. Results A total of 2,187 patients were included in analysis (Pre-COVID n = 1,572; COVID n = 615). Results were significant for decreased trauma volume but longer length of stay during COVID cohort, and for an increased proportion of males. No significant difference was found for other demographic variables, trauma mechanisms, or severity. Trauma volume patterns mirrored COVID rates in the state. Conclusions Despite a decline in trauma volume, other trauma patterns including severity and mechanism remained unchanged during the COVID-19 period. The decreased volume was not associated with a markedly lower clinical workload, change in team structure, or provider coverage re-distribution. Our data suggests that trauma volume and severity remained high enough during COVID-19 peak to necessitate full staffing, which may provide guidance in the event of a pandemic resurgence.
Patient-reported outcome measures for pediatric patients with sport-related injuries: a systematic review.

Despite a call to incorporate PROMs into all aspects of health care, little is known about which instruments are best-suited for a pediatric patient population with sport-related injury. The objective of this article was to perform a systematic review of the currently available evidence to determine which patient-reported outcome measures (PROMs) are used for pediatric patients with sports-related injuries, and to identify the associated psychometric properties and considerations for clinical utility. We conducted a literature search for articles on PROMs used in the pediatric population through electronic databases and via a manual search of reference lists and authors between 1990 and 2020. Articles were grouped based off of the PROM(s) included, and considerations for clinical utility and psychometric properties were extracted from each article. Thirty-nine articles were included in this review, from which twenty-two PROMs were identified - twelve PROMs were developed specifically for the pediatric population, four were modified versions of an adult scale, and six instruments were adult measures used in a pediatric population. Of the PROMs included in this review, the Oxford Ankle Foot Questionnaire for Children (OxAFQ-C) and the Pediatric Quality of Life Inventory (PedsQL) were the most comprehensive in their development and assessment. Several outcome measures used for pediatric patients had missing or inadequate measurement properties and considerations for clinical utility, particularly in regards to readability, responsiveness and interpretability. Clinicians and researchers should consider the measure's feasibility, acceptability, appropriateness and psychometric psychometric properties when selecting a PROM for use with the pediatric population.
Frontiers of microstructural imaging with diffusion MRI

Abstract Diffusion magnetic resonance imaging (MRI) is reviewed from basic concepts to advanced techniques and applications. There is a strong emphasis on the conceptual underpinnings of diffusion MRI, its close connection to tissue microstructure, and its applications to brain. Topics covered include diffusion tensor imaging, diffusional kurtosis imaging, q-space imaging, and white matter fiber tractography. The distinction between pure diffusion methods and tissue modeling methods is illustrated with specific examples. Recently proposed diffusion MRI approaches under active development are discussed.
Significance of “stretched” mineral inclusions for reconstructing P–T exhumation history

polymorph kyanite also has the capacity to retain tensile stresses if exhumed to Earth's surface after being trapped as an inclusion in plagioclase at P-T conditions within the kyanite stability field, with the stresses developed during exhumation sufficient to produce a transformation to anda - lusite. These results highlight the elastic environment that may arise during exhumation and provide a potential expla- nation of observed inclusions whose stability fields are well removed from P-T paths followed during exhumation. Abstract Analysis of mineral inclusions in chemically and physically resistant hosts has proven to be valuable for reconstructing the P-T exhumation history of high-grade metamorphic rocks. The occurrence of cristobalite-bear- ing inclusions in garnets from Gore Mountain, New York, is unexpected because the peak metamorphic conditions reached are well removed (>600 °C too cold) from the sta- bility field of this low-density silica polymorph that typi - cally forms in high temperature volcanic environments. A previous study of samples from this area interpreted pol- ymineralic inclusions consisting of cristobalite, albite and ilmenite as representing crystallized droplets of melt gen- erated during a garnet-in reaction, followed by water loss from the inclusion to explain the reduction in inclusion pressure that drove the transformation of quartz to cristo- balite. However, the recent discovery of monomineralic inclusions of cristobalite from the nearby Hooper Mine can- not be explained by this process. For these inclusions, we propose that the volume response to pressure and tempera- ture changes during exhumation to Earth's surface resulted in large tensile stresses within the silica phase that would be sufficient to cause transformation to the low-density (low- pressure) form. Elastic modeling of other common inclu- sion-host systems suggests that this quartz-to-cristobalite example may not be a unique case. The aluminosilicate
Taxpayer Standing: Maintaining Separation of Powers While Ensuring Democratic Administrative Action

In a landmark 2007 decision, the U.S. Supreme Court expanded its standing doctrine. Traditionally, the U.S. standing doctrine has been narrow, relying largely on the “cases and controversies” language of Article III of the U.S. Constitution. This doctrine has precluded thirdparty or taxpayer suits concerning administrative action. This Note compares the U.S. standing doctrine to that of South Africa, which has a much broader notion of who may bring suit. South Africa’s history with apartheid and distrust of government has led to a liberal standing doctrine in which any individual aggrieved by administrative action may bring suit to receive a written explanation from the offending agency. By exploring the doctrines, this Note argues that a similar type of standing in the United States would serve to democratize administrative action while still ensuring a constitutional separation of powers.
Learning Meaning Before Syntax

We present a simple computational model that includes semantics for language learning, as motivated by readings in the literature of children's language acquisition and by a desire to incorporate a robust notion of semantics in the field of Grammatical Inference. We argue that not only is it more natural to take into account semantics, but also that semantic information can make learning easier, and can give us a better understanding of the relation between positive data and corrections. We propose a model of meaning and denotation using finite-state transducers, motivated by an example domain of geometric shapes and their properties and relations. We give an algorithm to learn a meaning function and prove that it finitely converges to a correct result under a specific set of assumptions about the transducer and examples.
Inference for Optimal Dynamic Treatment Regimes Using an Adaptive m-Out-of-n Bootstrap Scheme

ummary A dynamic treatment regime consists of a set of decision rules that dictate how to individualize treatment to patients based on available treatment and covariate history. A common method for estimating an optimal dynamic treatment regime from data is Q-learning which involves nonsmooth operations of the data. This nonsmoothness causes standard asymptotic approaches for inference like the bootstrap or Taylor series arguments to breakdown if applied without correction. Here, we consider the m-out-of-n bootstrap for constructing confidence intervals for the parameters indexing the optimal dynamic regime. We propose an adaptive choice of m and show that it produces asymptotically correct confidence sets under fixed alternatives. Furthermore, the proposed method has the advantage of being conceptually and computationally much simple than competing methods possessing this same theoretical property. We provide an extensive simulation study to compare the proposed method with currently available inference procedures. The results suggest that the proposed method delivers nominal coverage while being less conservative than alternatives. The proposed methods are implemented in the qLearn R-package and have been made available on the Comprehensive R-Archive Network (http://cran.r-project.org/). Analysis of the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study is used as an illustrative example.
On Deep Multi-View Representation Learning

We consider learning representations (features) in the setting in which we have access to multiple unlabeled views of the data for representation learning while only one view is available at test time. Previous work on this problem has proposed several techniques based on deep neural networks, typically involving either autoencoder-like networks with a reconstruction objective or paired feedforward networks with a correlation-based objective. We analyze several techniques based on prior work, as well as new variants, and compare them experimentally on visual, speech, and language domains. To our knowledge this is the first head-to-head comparison of a variety of such techniques on multiple tasks. We find an advantage for correlation-based representation learning, while the best results on most tasks are obtained with our new variant, deep canonically correlated autoencoders (DCCAE).
Bistability in a Leaky Integrate-and-Fire Neuron with a Passive Dendrite

We examine the influence of dendritic load on the firing dynamics of a spatially extended leaky integrate-and-fire (LIF) neuron that explicitly includes spiking dynamics. We obtain an exact an- alytical solution for this model and use it to derive a return map that completely captures the dynamics of the system. Using the map, we find that dendritic properties can significantly change the firing dynamics of the system. Under certain conditions, the addition of the dendrite can change the LIF model from type 1 excitability to type 2 excitability and induce bistability between periodic firing and the quiescent state. We identify the mechanism that causes the periodic behavior in the bistable regime as somatodendritic ping-pong. Furthermore, we use the return map to fully explore the model parameter space in order to find regions where this bistable behavior occurs. We then give physical interpretations of the dependence of the bistable behavior on model parameters. Finally, we demonstrate that the simpler two-compartment model displays qualitatively similar dynamics to the more complicated ball-and-stick model.
Synthesis and physical properties of the new layered ternary tellurides MIrTe4 (M = Nb, Ta), and the structure of NbIrTe4

Abstract Two new ternary transition-metal chalcogenides, niobium iridium tetratelluride (NbIrTe4) and tantalum iridium tetratelluride (TaIrTe4), have been prepared by reaction of the elemental powders at 1000°C. The structure of NbIrTe4 has been determined by single-crystal X-ray diffraction methods. The compound crystallizes in space group C72v-Pmn21 of the orthorhombic system with four formula units in a cell of dimensions a = 3.768(3), b = 12.486(10), c = 13.077(9) A at 294 K. NbIrTe4 is a layered compound with a structure closely related to those of WTe2 and β-MoTe2, variants of the CdI2 structure type. The layers comprise buckled sheets of Te atoms, with the Nb and Ir atoms residing in distorted octahedral sites. Metal-metal bonding appears to be responsible for a close association of the Nb and Ir atoms. From Weissenberg photography, the compound TaIrTe4 is found to be isostructural to NbIrTe4, with cell dimensions a = 3.77(3), b = 12.37(6), c = 13.17(3) A. Electrical resistivity measurements along the a axis of both compounds show that they are metallic: ϱ 298 = 8.1 × 10 −5 and 1.2 × 10 −4 Ω cm for NbIrTe4 and TaIrTe4, respectively. Magnetic susceptibility measurements indicate essentially temperature-independent Pauli paramagnetism for both compounds: χm = 1.9 × 10−3 and 8.9 × 10−4 emu mol−1 for NbIrTe4 and TaIrTe4, respectively. The compounds NbIrTe4 and TaIrTe4 appear to belong to a larger class of compounds MM′Te4 with M = Nb, Ta and M′ = Ru, Os, Rh, Ir.
Variation among Species in the Temperature Dependence of the Reappearance of Variable Fluorescence following Illumination

The relationship between the thermal dependence of the reappearance of chlorophyll variable fluorescence following illumination and temperature dependence of the apparent Michaelis constant (Km) of NADH hydroxypyruvate reductase for NADH was investigated in cool and warm season plant species. Brancker SF-20 and SF-30 fluorometers were used to evaluate induced fluorescence transients from detached leaves of wheat (Triticum aestivum L. cv TAM-101), cotton (Gossypium hirsutum L. cv Paymaster 145), tomato (Lycopersicon esculentum cv Del Oro), bell pepper (Capsicum annuum L. cv California Wonder), and petunia (Petunia hybrida cv. Red Sail). Following an illumination period at 25°C, the reappearance of variable fluorescence during a dark incubation was determined at 5°C intervals from 15°C to 45°C. Variable fluorescence recovery was normally distributed with the maximum recovery observed at 20°C in wheat, 30°C in cotton, 20°C to 25°C in tomato, 30 to 35°C in bell pepper and 25°C in petunia. Comparison of the thermal response of fluorescence recovery with the temperature sensitivity of the apparent Km of hydroxypyruvate reductase for NADH showed that the range of temperatures providing fluorescence recovery corresponded with those temperatures providing the minimum apparent Km values (viz. the thermal kinetic window).
Electric field induced structure in dense suspensions

Abstract This paper presents measurements of the structure of dense suspensions of colloidal spheres subject to electric fields. Scattering dichroism measurements, performed as a function of wavelength, probed the anisotropy in the pair distribution function of submicrometer silica spheres, following the application of electric fields. The results indicate that at lower concentrations, high aspect ratio fibrils are formed upon application of the electric fields. As the concentration is increased, branching of the fibrillar structure reduces the anisotropy of the suspension with a subsequent decrease of the measured dichroism. The time scales of structure formation and relaxation are also considered. The response time of the fluid decreases as the applied field is increased and as the particle volume fraction is decreased. The relaxation time increases with increasing particle size but is insensitive to concentration.
Turbulence in coastal fronts near the mouths of Block Island and Long Island Sounds

Abstract Measurements of turbulence were performed in four frontal locations near the mouths of Block Island Sound (BIS) and Long Island Sound (LIS). These measurements extend from the offshore front associated with BIS and Mid-Atlantic Bight Shelf water, to the onshore fronts near the Montauk Point (MK) headland, and the Connecticut River plume front. The latter feature is closely associated with the major fresh water input to LIS. Turbulent kinetic energy (TKE) dissipation rate, e, was obtained using shear probes mounted on an autonomous underwater vehicle. Offshore, the BIS estuarine outflow front showed, during spring season and ebb tide, maximum TKE dissipation rate, e, estimates of order 10 − 5 W/kg, with background values of order 10 − 6 to 10 − 9 W/kg. Edwards et al. [Edwards, C.A., Fake, T.A., and Bogden, P.S., 2004a. Spring–summer frontogenesis at the mouth of Block Island Sound: 1. A numerical investigation into tidal and buoyancy-forced motion. Journal of Geophysical Research 109 (C12021), doi:10.1029/2003JC002132.] model this front as the boundary of a tidally driven, baroclinically adjusted BIS flow around the MK headland eddy. At the entrance to BIS, near MK, two additional fronts are observed, one of which was over sand waves. For the headland site front east of MK, without sand waves, during ebb tide, e estimates of 10 − 5 to 10 − 6 W/kg were observed. The model shows that this front is at the northern end of an anti-cyclonic headland eddy, and within a region of strong tidal mixing. For the headland site front further northeast over sand waves, maximum e estimates were of order 10 − 4 W/kg within a background of order 10 − 7 –10 − 6 W/kg. From the model, this front is at the northeastern edge of the anti-cyclonic headland eddy and within the tidal mixing zone. For the Connecticut River plume front, a surface trapped plume, during ebb tide, maximum e estimates of 10 − 5 W/kg were obtained, within a background of 10 − 6 to 10 − 8 W/kg. Of all four fronts, the river plume front has the largest finescale mean-square shear, S 2 ~ 0.15 s − 2 . All of the frontal locations had local values of the buoyancy Reynolds number indicating strong isotropic turbulence at the dissipation scales. Local values of the Froude number indicated shear instability in all of the fronts.
Phenomenological Causal Model of Nuclear Decay, Assuming Interaction with Neutrino Sea.

As previous ly out l ined (1), the neutr ino sea is receiving increased considerat ion as an energy source and sink in cosmological theories. On the basis of more recent da ta (2.a), i t is now possible to predict , w i th a reasonable degree of accuracy, the na tu re of this more or less general ized isotropic flux, the const i tuents of which are four stable uncharged particles, at two widely different mass levels :
Ultrafast infrared–Raman studies of vibrational energy redistribution in polyatomic liquids

Vibrational energy relaxation and vibrational cooling of polyatomic liquids were studied with the ultrafast infrared–Raman (IR–Raman) technique. In the IR–Raman technique, a type of two-dimensional vibrational spectroscopy, a vibrational transition is pumped with a mid-infrared pulse and the instantaneous populations of all Raman-active transitions are simultaneously probed via incoherent anti-Stokes Raman scattering of a time-delayed visible pulse. The theoretical framework for these measurements, including force–force correlation function methods and perturbative techniques, is reviewed. Experimental aspects of the IR–Raman technique are discussed, including laser instrumentation, experimental set-up, the nature of the pumping and probing processes, detection sensitivity and optical background, and the interpretation of results including spectroscopic artifacts. Then examples are provided from recent research by our group, focusing on timely problems such as the pseudo-vibrational cascade, the dynamics of doorway vibrations, dynamics of overtones with Fermi resonance, multiple vibrational excitations via combination band pumping and spectral evolution in associated liquids. Copyright © 2000 John Wiley & Sons, Ltd.
A Political-Economic History of FCC Policy on Minority Broadcast Ownership

This retrospective study on Federal Communications Commission policy addresses why minority broadcast ownership has waned as a civil rights issue since the 1960s, and it considers the re-emergence of this concern in the modern media reform movement. From the authors' examination, politics, neoliberal economic philosophy, and media ownership consolidation have contributed to the diminution of minority broadcast ownership in significant ways. The authors' findings have important implications for epistemic communities seeking to redress the lack of minority-owned broadcast facilities.
CFD Challenge: Solutions Using the Spectral Element Solver NEKTAR

Flow problems in cardiovascular mechanics involve complex geometries and pulsatile flow that may give rise to instabilities, especially in pathological cases. High-order methods are particularly suitable for resolving such unsteady phenomena whereas low-order methods may exhibit excessive dissipation and hence suppress any such physical instabilities. This, for example, is the case for certain type of cerebral aneurysms, see [1], for which we have demonstrated that shear layer instabilities may be triggered even at physiological flow rates, giving rise to audible frequencies in the range of 10Hz to 50 Hz. Similar phenomena may be present in stenotic arteries, where a jet type flow may develop that is also susceptible to temporal instabilities, especially during the decelerating systole.Copyright © 2012 by ASME
Femtosecond real-time probing of reactions. V. The reaction of IHgI

The dissociation reaction of HgI2 is examined experimentally using femtosecond transition-state spectroscopy (FTS). The reaction involves symmetric and antisymmetric coordinates and the transition-state is well-defined: IHgI*-->[IHgI] [double-dagger]@B| Q[sub S[script ']]Q[sub a[script ']]q -->HgI+I. FTS is developed for this class of ABA-type reactions and recurrences are observed for the vibrating fragments (symmetric coordinate) along the reaction coordinate (antisymmetric coordinate). The translational motion is also observed as a "delay time" of the free fragments. Analysis of our FTS results indicates that the reaction wave packet proceeds through two pathways, yielding either I(2P3/2) or I*(2P1/2) as one of the final products. Dissociation into these two pathways leads to HgI fragments with different vibrational energy, resulting in distinct trajectories. Hence, oscillatory behaviors of different periods in the FTS transients are observed depending on the channel probed (~300 fs to ~1 ps). These results are analyzed using the standard FTS description, and by classical trajectory calculations performed on model potentials which include the two degrees of freedom of the reaction. Quantum calculations of the expected fluorescence of the fragment are also performed and are in excellent agreement with experiments.
Comparative effects of continuous warm blood and intermittent cold blood cardioplegia on coronary reactivity.

Background Cardioplegia is known to affect coronary vascular reactivity. We examined the effects of intermittent cold and continuous warm blood cardioplegia on β-adrenoceptor–mediated, adenosine triphosphate–sensitive K + (K + ATP )–channel–mediated, and endothelium-dependent relaxation and on the myogenic tone of coronary arterioles. Methods Pigs were placed on cardiopulmonary bypass. Hearts were arrested for 1 hour with a cold blood cardioplegic solution administered intermittently (n=12; iCB-CP) or with a warm blood cardioplegic solution delivered continuously (n=12; cWB-CP). Selected hearts (n=6 in each group) were then reperfused for 1 hour. In vitro relaxation responses of precontracted microvessels (50 to 160μm) were studied in a pressurized no-flow state. Results Relaxation in response to isoproterenol (β-adrenergic agonist) was similar after iCB-CP and cWB-CP, whereas forskolin (adenylate cyclase activator)–induced relaxation was impaired more after iCB-CP than after cWB-CP. After reperfusion the respective responses were similar. Both iCB-CP and cWB-CP preserved receptor-mediated, endothelium-dependent relaxation in response to adenosine, 5 * -diphosphate; non–receptor-mediated endothelium-dependent relaxation in response to A23187; endothelium-independent cyclic guanosine monophosphate–mediated relaxation in response to sodium nitroprusside, and K + ATP -channel–mediated relaxation. Relaxations in response to 8-bromo-cyclic guanosine monophosphate (a cyclic guanosine monophosphate–dependent protein kinase activator) and to 8-bromo-cyclic adenosine monophosphate (a cyclic adenosine monophosphate–dependent protein kinase activator) were impaired after iCB-CP alone and after reperfusion, whereas the respective responses were not affected after cWB-CP. Myogenic tone was decreased similarly after iCB-CP and cWB-CP but was not further altered after reperfusion. Cardiac function was similar after iCB-CP and cWB-CP. Conclusions These results suggest that cWB-CP is similar to iCB-CP in its ability to preserve endothelium-dependent relaxation and K + ATP -channel function. The superior preservation of β-adrenergic-cyclic adenosine monophosphate–mediated coronary responses after cWB-CP is brief and associated with minimal improvement of myocardial function and myogenic tone.
Suprachoroidal Drug Delivery to the Back of the Eye Using Hollow Microneedles

Purpose In this work, we tested the hypothesis that microneedles provide a minimally invasive method to inject particles into the suprachoroidal space for drug delivery to the back of the eye.
Gray matter prefrontal changes in type 2 diabetes detected using MRI.

Purpose To examine the volumes of the gray and white matter both globally and regionally in patients diagnosed with type 2 diabetes and controls. Materials and Methods Our samples were comprised of 26 patients with type 2 diabetes, 26 patients with diabetes and major depressive disorder, and 25 nondiabetic, nondepressed control subjects. All subjects were studied cross-sectionally on a 1.5 T scanner and were recruited from medicine/diabetes clinics. Both gray and white matter volumes were estimated using an automated method, and the prefrontal areas studied included the anterior cingulate, the gyrus rectus, and the orbitofrontal regions. Results Patients with diabetes, both with and without depression, had smaller total brain gray matter volumes when compared with the control subjects after controlling for age, intracranial volume, and years of education. This group also had smaller gray matter volumes in the anterior cingulate and orbitofrontal regions when compared with the controls after additionally controlling for total gray matter volume. The depressed and nondepressed diabetic groups did not differ on any neuroimaging measure. Cerebrovascular risk factors correlated negatively with gray matter volumes. Conclusion The findings indicate that type 2 diabetes is associated with specific neuroanatomical abnormalities in the prefrontal gray matter. Vascular disease might contribute to the findings observed in our sample. These observations have implications for the behavioral sequelae of diabetes. J. Magn. Reson. Imaging 2007. © 2007 Wiley-Liss, Inc.
Titanium Nitride Epitaxy on Tungsten (100) by Sublimation Crystal Growth

Titanium nitride crystals were grown from titanium nitride powder on tungsten by the sublimation-recondensation technique. The bright golden TiN crystals displayed a variety of shapes including cubes, truncated tetrahedrons, truncated octahedrons, and tetrahedrons bounded by (111) and (100) crystal planes. The TiN crystals formed regular, repeated patterns within individual W grains that suggested epitaxy. X-ray diffraction and electron backscattering diffraction revealed that the tungsten foil was highly textured with a preferred foil normal of (100) and confirmed that the TiN particles deposited epitaxially with the orientation TiN(100)/W(100) and TiN[100]/W[110], that is, the unit cells of the TiN crystals were rotated 45{sup o} with respect to the tungsten. Because of its larger coefficient of thermal expansion compared to W, upon cooling from the growth temperature, the TiN crystals were under in-plane tensile strain, causing many of the TiN crystals to crack.
Differentiation requires continuous regulation.

Article de synthese traitant des mecanismes biochimiques et genetiques regulant le phenomene de differenciation cellulaire pour 2 especes d'insectes presentant ou non des mutations dans leur genome
Polar Cap Arcs: A Review

Abstract This article reviews both the observational and theoretical studies of polar cap arcs. These arcs are the auroral arcs that occur in the polar cap or in the poleward regions of the auroral oval. The following related topics are briefly discussed in the article: (1) dayside aurora; (2) oval/substorm aurora; and (3) large-scale convection, current, and precipitation configurations at high latitudes during northward interplanetary magnetic fields
A transformed time-dependent Michaelis–Menten enzymatic reaction model and its asymptotic stability

The dynamic form of the Michaelis–Menten enzymatic reaction equations provide a time-dependent model in which a substrate $$S$$ reacts with an enzyme $$E$$ to form a complex $$C$$ which in turn is converted into a product $$P$$ and the enzyme $$E$$ . In the present paper, we show that this system of four nonlinear equations can be reduced to a single nonlinear differential equation, which is simpler to solve numerically than the system of four equations. Applying the Lyapunov stability theory, we prove that the non-zero equilibrium for this equation is globally asymptotically stable, and hence that the non-zero steady-state solution for the full Michaelis–Menten enzymatic reaction model is globally asymptotically stable for all values of the model parameters. As such, the steady-state solutions considered in the literature are stable. We finally discuss properties of the numerical solutions to the dynamic Michaelis–Menten enzymatic reaction model, and show that at small and large time scales the solutions may be approximated analytically.
Utilization of cement kiln dust (CKD) to enhance mine tailings-based geopolymer bricks

Abstract This paper studies the feasibility of enhancing the physical and mechanical properties and the durability of copper mine tailings (MT)-based geopolymer bricks with cement kiln dust (CKD). The effects of CKD content (0–10%), sodium hydroxide (NaOH) concentration (10 and 15 M) and initial water content (12–20%) on unconfined compressive strength (UCS), water absorption, and weight and strength losses after immersion in water are studied. To shed light on the mechanism for the contribution of CKD to geopolymerization, microscopic and spectroscopic techniques including scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy are used to investigate the micro/nanostructure and the elemental and phase composition of geopolymer brick specimens. The results show significant improvement of UCS and durability when CKD is used. Water absorption, however, slightly increases due to the hydration of Ca in the added CKD. The enhancement of UCS and durability is attributed to the improving effect of CKD on dissolution of aluminosilicate species, formation of CaCO 3 , and integration of Ca into the geopolymer gel.
Population coding under normalization

A common computation in visual cortex is the divisive normalization of responses by a pooled signal of the activity of cells within its neighborhood. From a geometrical point of view, normalization constraints the population response to high-contrast stimuli to lie on the surface of a high-dimensional sphere. Here we study the implications this constraint imposes on the representation of a circular variable, such as the orientation of a visual stimulus. New results are derived for the infinite dimensional case of a homogeneous populations of neurons with identical tuning curves but different orientation preferences. An important finding is that the ability of the population to discriminate between any two orientations depends exclusively on the Fourier amplitude spectrum of the orientation tuning curve. We also study the problem of encoding by a finite set of neurons. A central result is that, under normalization, optimal encoding can be achieved by a finite number of neurons with heterogeneous tuning curves. In other words, increasing the number of neurons in the population does not always allow for an improved population code. These results are used to estimate the number of neurons involved in the coding of orientation at one position in the visual field. If the cortex were to code orientation optimally, we find that a small number (∼4) of neurons should suffice.
Two Phase Flow Mapping and Transition Under Microgravity Conditions

In this paper, recent microgravity two-phase flow data for air-water, air-water-glycerin, and air- water-Zonyl FSP mixtures are analyzed for transition from bubbly to slug and from slug to annular flow. It is found that Weber number-based maps are inadequate to predict flow-pattern transition, especially over a wide range of liquid flow rates. It is further shown that slug to annular flow transition is dependent on liquid phase Reynolds number at high liquid flow rate. This effect may be attributed to growing importance of liquid phase inertia in the dynamics of the phase flow and distribution. As a result a new form of scaling is introduced to present data using liquid Weber number based on vapor and liquid superficial velocities and Reynolds number based on liquid superficial velocity. This new combination of the dimensionless parameters seem to be more appropriate for the presentation of the microgravity data and provides a better flow pattern prediction and should be considered for evaluation with data obtained in the future. Similarly, the analysis of bubble to slug flow transition indicates a strong dependence on both liquid inertia and turbulence fluctuations which seem to play a significant role on this transition at high values of liquid velocity. A revised mapping of data using a new group of dimensionless parameters show a better and more consistent description of flow transition over a wide range of liquid flow rates. Further evaluation of the proposed flow transition mapping will have to be made after a wider range of microgravity data become available.
Phases of helium monolayers: search and discovery

Abstract In this article we describe from a historical perspective the experimental and theoretical interplay amongst the three authors, their students, and many colleagues which led to the initial discoveries of several of the phases of 4 He and 3 He adsorbed on graphite.
Safe and Convenient Procedure for Solvent Purification

This contribution describes a general method for the purification of solvents for use with air and moisture sensitive reactions. This procedure provides a nonhazardous alternative to distillations and vacuum transfers and does not require undue supervision or cooling, yet allows for the rapid collection of large quantities of extremely pure solvents on demand. Solvents are rigorously degassed in 18 L reservoirs and passed through two sequential purification columns. Protic contaminants are removed with activated alumina, while a supported copper catalyst is used to remove trace oxygen from hydrocarbons. The purification system is interfaced with either a glove box or Schlenk manifold for the anhydrous/anaerobic collection of solvents. Solvents purified by this method and tested with stock solutions of sodium benzophenone ketyl or titanocene dichloride/zinc dust are free of oxygen at least to the ppm level. Furthermore, this system may be used for the in-line purification of gases and is easily scaled down...
Clinical patterns, natural history, and progression of ulcerative colitis. A long-term follow-up of 1116 patients

We studied the natural history of ulcerative colitis (UC) by following 1116 patients in whom UC had been diagnosed or confirmed at The Cleveland Clinic Foundation between 1960 and 1983. Data before 1973 were obtained retrospectively. Criteria for inclusion in the study were: a diagnosis of UC confirmed by clinical, radiographic, endoscopic, and histologic examination; disease location that could be defined as one of three categories (proctosigmoiditis, pancolitis, or left-sided colitis); and a follow-up of at least five years (mean = 12.7 years). Mean age at diagnosis was 32 years. Of the 1116 patients, 46.2% (516) had proctosigmoiditis; 36.7% (410) had pancolitis (colitis of the entire large intestine); and 17.0% (190) had left-sided colitis (from the dentate line to the splenic flexure). Early complications (within two years of diagnosis) included colonic hemorrhage (16.7%) and toxic colitis (12.7%). Complications were highest among patients with pancolitis. Surgery was required for 37.6% of the patients. Primary indications for surgery included chronic or intractable disability (40.2%), fulminating medical failure (16.9%), and colonic dilatation (18.4%). At the most recent follow-up, the disease had extended (progressed to a more serious category) in 53.8% of the patients, although 67.2% were asymptomatic and only 37.0% were on medications. Both the final disease destination and the initial diagnosis impacted cumulative colectomy-ileostomy rates. Factors associated with extension were toxic colitis (P < 0.0001); extent of disease at diagnosis (P < 0.0001); joint symptoms (P = 0.0008); younger age at diagnosis (P = 0.06); and severe bleeding (P = 0.07).
Treatment of cryosurgery in the premalignant and benign lesions of the skin

Abstract Cryosurgery, in the treatment of premalignant and benign lesions of the skin and mucous membranes, competes favorably with other therapeutic methods, including excision, electrosurgery, laser therapy, curettage, topical chemotherapy, dermabrasion, and chemical peel.
Chestnut Leaf Inoculation Assay as a Rapid Predictor of Blight Susceptibility

Newhouse, A. E., Spitzer, J. E., Maynard, C. A., and Powell, W. A. 2014. Chestnut leaf inoculation assay as a rapid predictor of blight susceptibility. Plant Dis. 98:4-9. American chestnuts (Castanea dentata), effectively eliminated from eastern North America by chestnut blight in the twentieth century, are the subject of multiple restoration efforts. Screening individual trees (or tree types) for blight resistance is a critical step in all of these programs. Traditional screening involves inoculating stems of >3-year-old trees with the blight fungus (Cryphonectria parasitica), then measuring resulting cankers a few months later. A quicker, nondestructive, quantitative assay, usable on younger plants, would enhance restoration efforts by speeding the screening process. The assay presented here meets these requirements by inoculating excised leaves with the blight fungus and measuring resulting necrotic lesions. Leaves can be collected from few-month-old seedlings or fully mature trees, and results are measured after less than a week. Leaves from several lines of both American and Chinese chestnuts were inoculated, as well as the congener Allegheny chinquapin, and experimental leaf assay results correlate well with stem assay results from these species. Inoculations with virulent and hypovirulent blight fungi strains also showed relative patterns similar to traditional inoculations. Given the correlations to established stem assay results, this procedure could be a valuable tool to quickly evaluate blight resistance in American chestnut trees used for restoration. The American chestnut (Castanea dentata (Marshall) Borkh.) was once a widespread and integral part of the ecology and economy of the eastern United States. The timber was strong, straightgrained, and rot-resistant, and the nuts provided nutrition and income to humans, as well as a reliable mast crop for wildlife. However, starting around the turn of the twentieth century, chestnut blight eradicated nearly all mature American chestnut trees throughout the chestnut’s North American range. Chestnut blight is caused by the necrotrophic fungal pathogen Cryphonectria parasitica (Murr.) Barr., which colonizes bark wounds, causes cankers, and eventually girdles trunks of susceptible trees. No practical prevention or treatment methods have been found for landscapescale use, and various restoration programs have been underway for many years with the goal of producing blight-resistant trees. Success in these programs is determined by field inoculation trials, which typically involve inoculating trees that have been growing outdoors for at least 3 years (9,12). While American chestnut grows relatively quickly compared to other North American hardwoods, it still may be 5 years or more before a given tree can be screened for blight resistance.
Modeling and simulation of constituent particle clustering and distribution in rolled aluminum alloys

It is recognized that corrosion damage in aluminum alloys is the direct result of local galvanic coupling between constituent particles and the metal matrix. Heavily clustered groups of constituent particles have been shown to form the most severe corrosion pits, and the morphology of these pits has been found to exhibit a strong correlation with that of the instigating particle cluster. To predict damage evolution accurately in three dimensions, the spatial distribution of the constituent particles in a given material must be quantified. The tomographic reconstruction methods currently available are time consuming and possess characteristic length scales that are insufficient for large-scale corrosion studies. To accommodate this larger length scale, a model for three-dimensional constituent particle microstructure is proposed. This model employs a fusion of classic stereological techniques and qualitative observations to describe the constituent particle microstructure of rolled aluminum alloys in three dimensions. A method is described for generating statistically representative three-dimensional constituent particle microstructure from two-dimensional orthogonal cross sections. This novel simulation algorithm allows for detailed three-dimensional particle microstructure simulations to be carried out using standard optical microscopy and image analysis techniques.
A novel method for generating corneal haze in anterior stroma of the mouse eye with the excimer laser

Refractive surgery is a popular method used to reduce or eliminate dependence on glasses and contact lenses. Corneal haze is one of the common complications observed after photorefractive keratectmomy (PRK). The objective of this study was to develop an in vivo mouse model that consistently produces moderate to severe corneal haze in the anterior stroma of the mouse cornea after excimer laser treatment to study myofibroblast biology and corneal wound healing in a genetically defined model. Regular- or irregular-phototherapeutic keratectomy (PTK) was performed on black C57BL/6 mice with the Summit Apex excimer laser (Alcon, Ft. Worth, TX). Different numbers of laser pulses (45; ablation depth ~10 μm) were fired on the central cornea, after scraping the epithelium prior to excimer laser ablation. Irregularity was generated by positioning a fine mesh screen in the path of laser after firing 50% of the pulses. Eyes were collected 1, 2, 3 or 4 weeks after the procedure. Haze formation was gauged with slit lamp biomicroscopy. Immunocytochemistry was used to determine number of myofibroblasts in the mouse cornea using antibodies specific for the myofibroblast marker alpha-smooth muscle actin (SMA). The numbers of SMA-positive cells/400X microscopic were determined by counting within the stroma. Statistical analysis was performed using analysis of variance (AVOVA) with the Bonferonni-Dunn adjustment for repeated measures. Regular-PTK with epithelial scrape (Group 3) and irregular-PTK with epithelial scrape (Group 4) in the mouse eyes were performed to produce corneal haze. Eyes collected 4 weeks after regular- or irregular-PTK after epithelial scrape showed 22 ± 6.6 (Group 3) or 34 ± 7.9 (Group 4) SMA-positive cells in the anterior cornea. The difference in the SMA-positive cells detected among the groups was statistically significant (p < 0.01). Less than 4 SMA-positive cells were detected in the tissue sections of the mouse eyes collected after 1, 2 or 3 weeks of regular (Group 3) or irregular PTK (Group 4) or controls (Group 1 and 2). The optimized PTK excimer laser conditions developed in this study produces haze selectively in anterior stroma of the mouse cornea immediately beneath the epithelial basement membrane. Irregular PTK performed after epithelial scrape by applying 45 laser pulses was found to be the most effective method to generate myofibroblasts. This PTK technique for inducing haze in mouse cornea in vivo provides a useful model for studying wound healing and myofibroblast biology in transgenic mice.
Blood glucose regulation in larval and adult salamanders (Ambystoma tigrinum).

Blood glucose in Ambystoma tigrinum is regulated at a lower level in larval (18.4 ± 0.7 mg%) than in adult (27.8 ± 0.8 mg%) animals. The difference is observed at all seasons, and is not related to differences in size, diet or sexual maturity. A difference in the blood glucose regulating mechanism in pre- and post-metamorphic animals is further shown by three other observations: (1) larvae are more insulin sensitive than adults; (2) larvae have a slightly greater glucose tolerance than adults; and (3) pancreatectomy causes a more severe hyperglycemia in adults than in larvae. The best hypothesis to account for all of these observations is that an increase in the amount and/or activity of insulin antagonistic hormones occurs at metamorphosis.
Diet and serum lipids: Controlled studies in the United States

The influence of dietary fat on serum lipids is well established. The general principles of a fat-modified diet--calorie control and the amount and composition of dietary fat--are demonstrated in studies in which nutrient composition was systematically altered. Weight loss, even when caloric deficit involves no other changes in nutrients, reduces serum lipids. With isocaloric diets, the fatty acid composition rather than the amount of fat influences the serum cholesterol concentration. Saturated fatty acids are twice as effective in raising serum cholesterol levels as polyunsaturated fatty acids are in reducing them. The amount of cholesterol in the diet alters the amount in the serum by approximately 5 mg/dl for every 100 mg of change in diets with less than 300 mg/1000 kcal. Cholesterol in excess of this amount has no additional effect. With no dietary cholesterol, serum lipids are unaffected by the fat composition. In the presence of dietary cholesterol, serum lipids are affected by saturated and polyunsaturated fatty acids through an interaction with cholesterol. Polyunsaturates counteract the influence of both saturated fatty acids and cholesterol. The more cholesterol there is in the diet, the more polyunsaturated fatty acids are required to counteract its effect. Both the fatty acid composition of the lipoproteins and lipid metabolism are affected by the fat and cholesterol composition of the diet.