cssi/SciSciGPT-SciSciNet huggingface dataset:
The transcriptional repressor Bcl6 controls the stability of regulatory T cells by intrinsic and extrinsic pathways

Foxp3(+) regulatory T (Treg) cells are essential to maintain immune homeostasis, yet controversy exists about the stability of this cell population. Bcl6-deficient (Bcl6(-/-) ) mice develop severe and spontaneous T helper type 2 (Th2) inflammation and Bcl6-deficient Treg cells are ineffective at controlling Th2 responses. We used a lineage tracing approach to analyse the fate of Treg cells in these mice. In the periphery of Bcl6(-/-) mice, increased numbers of Foxp3-negative 'exTreg' cells were found, particularly in the CD25(+) population. ExTreg cells from Bcl6(-/-) mice expressed increased interleukin-17 (IL-17) and extremely elevated levels of Th2 cytokines compared with wild-type exTreg cells. Although Treg cells normally express only low levels of cytokines, Treg cells from Bcl6(-/-) mice secreted higher levels of IL-4, IL-5, IL-13 and IL-17 than wild-type conventional T cells. Next, Treg-specific conditional Bcl6-deficient (Bcl6(Foxp3-/-) ) mice were analysed. Bcl6(Foxp3-/-) mice do not develop inflammatory disease, indicating a requirement for non-Treg cells for inflammation in Bcl6(-/-) mice, and have normal numbers of exTreg cells. We induced Th2-type allergic airway inflammation in Bcl6(Foxp3-/-) mice, and found that while exTreg cytokine expression was normal, Bcl6-deficient Treg cells expressed higher levels of the Th2-specific regulator Gata3 than Bcl6(+) Treg cells. Bcl6(Foxp3-/-) mice had increased numbers of Th2 cells after induction of airway inflammation and increased T cells in the bronchoalveolar lavage fluid. These data show both Treg-intrinsic and Treg-extrinsic roles for Bcl6 in controlling Treg cell stability and Th2 inflammation, and support the idea that Bcl6 expression in Treg cells is critical for controlling Th2 responses.
COX-derived prostanoid pathways in gastrointestinal cancer development and progression: novel targets for prevention and intervention.

Abstract Arachidonic acid metabolism through cyclooxygenase (COX) pathways leads to the generation of biologically active eicosanoids. Eicosanoid expression levels vary during development and progression of gastrointestinal (GI) malignancies. COX-2 is the major COX-isoform responsible for G.I. cancer development/progression. COX-2 expression increases during progression from a normal to cancerous state. Evidence from observational studies has demonstrated that chronic NSAID use reduces the risk of cancer development, while both incidence and risk of death due to G.I. cancers were significantly reduced by daily aspirin intake. A number of randomized controlled trials (APC trial, Prevention of Sporadic Adenomatous Polyps trial, APPROVe trial) have also shown a significant protective effect in patients receiving selective COX-2 inhibitors. However, chronic use of selective COX-2 inhibitors at high doses was associated with increased cardiovascular risk, while NSAIDs have also been associated with increased risk. More recently, downstream effectors of COX-signaling have been investigated in cancer development/progression. PGE 2 , which binds to both EP and PPAR receptors, is the major prostanoid implicated in the carcinogenesis of G.I. cancers. The role of TXA 2 in G.I. cancers has also been examined, although further studies are required to uncover its role in carcinogenesis. Other prostanoids investigated include PGD 2 and its metabolite 15d-PGJ2, PGF 1α and PGI 2 . Targeting these prostanoids in G.I. cancers has the promise of avoiding cardiovascular toxicity associated with chronic selective COX-2 inhibition, while maintaining anti-tumor reactivity. A progressive sequence from normal to pre-malignant to a malignant state has been identified in G.I. cancers. In this review, we will discuss the role of the COX-derived prostanoids in G.I. cancer development and progression. Targeting these downstream prostanoids for chemoprevention and/or treatment of G.I. cancers will also be discussed. Finally, we will highlight the latest pre-clinical technologies as well as avenues for future investigation in this highly topical research field.
Numerical modeling of the reduction of nitric oxide by ethylene over Cu-ZSM-5 under lean conditions

Abstract Some catalysts such as copper zeolites have shown promise for direct NO decomposition and selective NO reduction via hydrocarbons in lean exhausts. This paper describes modeling calculations for the performance of a Cu-ZSM-5 NO x reduction catalyst. The numerical model simulates the multi-component transport and reaction processes that occur within a catalyzed monolith support. The surface boundary conditions for the reacting species are satisfied through the use of multi-dimensional Newton–Raphson iteration. The model is used to formulate global rate expressions for the oxidation of C 2 H 4 and the reduction of NO by adjusting kinetic parameters until predicted conversion efficiencies match experimental data. Results from simulation of NO reduction by C 2 H 4 are compared to previous simulation of NO reduction by C 3 H 6 and provide a detailed explanation of the differences between the efficiency of C 2 H 4 and C 3 H 6 as reductants. Then the numerical model is compared to data from higher space velocities to test the validity of the kinetic model. The comparison shows that additional optimization of the kinetic parameters is required. Nonetheless, the simulated interactions within the catalytic passage demonstrate important features of selective NO reduction.
The Time-of-Flight System on the Goddard Medium Energy Gamma-Ray Telescope

A scintillation counter time-of-flight system has been incorporated into the Goddard 50 cm by 50 cm spark chamber gamma-ray telescope. This system, utilizing constant fraction timing and particle position compensation, digitizes up to 10 ns time differences to six bit accuracy in less than 500 ns. Event selection decisions, discriminating against upward-moving particles, are made prior to spark chamber triggering. The performance of this system during a November 1978 balloon flight is discussed.
PAM—a noniterative approximate solution method for closed multichain queueing networks

Abstract Approximate MVA algorithms for separable queueing networks are based upon an iterative solution of a set of modified MVA formulas. Although each iteration has a computational time requirement of O( MK 2 ) or less, many iterations are typically needed for convergence to a solution. ( M denotes the number of queues and K the number of closed chains or customer classes.) We present some faster approximate solution algorithms that are noniterative . They are suitable for the analysis and design of communication networks which may require tens to hundreds, perhaps thousands, of closed chains to model flow-controlled virtual channels. The basis of our method is the distribution of a chain's population proportional to loads to get initial estimates of mean queue lengths. This is the same basis used in the derivation of proportional upper bounds for single-chain networks; for a multichain network, such a proportional distribution leads to approximations rather than upper bounds of chain throughputs. Nevertheless, these approximate solutions provide chain throughputs, mean end-to-end delays, and server utilizations that are sufficiently accurate for the analysis and design of communication networks and possibly other distributed systems with a large number of customer classes. Three PAM algorithms of increasing accuracy are presented. Two of them have time and space requirements of O( MK ). The third algorithm has a time requirement of O( MK 2 ) and a space requirement of O( MK ).
Entre movimiento y partido: la transformación del republicanismo francés de mediados del siglo XIX *

Resumen es: La protesta social ha sido definida, tradicionalmente, como una alternativa a la accion electoral. El autor sostiene que esta dicotomia es producto de co...
Reactions of tellurium chloride pentafluoride, TeF5Cl, with nitrogen nucleophiles. Preparation and characterization of the adducts (TeF4)2·NR2Cl, where R = CH3, C2H5

Abstract Reactions of TeF 5 Cl with the nitrogen nucleophiles LiN=C(CF 3 ) 2 , [(CH 3 ) 3 Si] 2 NH, and (CH 3 ) 3 SiNR 2 , Where R = CH 3 , C 2 H 5 , result in the reduction of the tellurium to Te(IV) and chlorination of the respective nucleophile. Analogous results are obtained in the reactions of TeF 5 Cl with (CH 3 ) 3 SiCN, C 6 F 5 Li, and C 6 F 5 SLi. In the case of (CH 3 ) 3 SiNR 2 , the new adducts (TeF 4 ) 2 ·NR 2 Cl are obtained in high yield. These compounds have been identified through their infrared, 1 H, 19 F, and 125 Te NMR, and mass spectra as well as by elemental analysis.
ON COLORED QUANDLE LONGITUDES AND ITS APPLICATIONS TO TANGLE EMBEDDINGS AND VIRTUAL KNOTS

Given a long knot diagram D and a finite quandle Q, we consider the set of all quandle colorings of D with a fixed color q of its initial arc. Using this set we define the family $\Phi_{Q}^{q}(K)$ of quandle automorphisms which is a knot invariant. For every element x ∈ Q one can consider the formal sum $S_{\Phi}^{x}(K) = \sum_{\phi}\phi(x)$, taken over all $\phi \in \Phi_{Q}^{q}$. Such formal sums can be applied to a tangle embedding problem and recognizing non-classical virtual knots.
On the structure of wall‐bounded turbulent flows

The variable-interval time-averaging (VITA) technique developed by Blackwelder and Kaplan is applied to data obtained from large-eddy simulation of turbulent channel flow in an investigation of the organized structures associated with the bursting phenomenon in the near-wall region. Conditionally averaged velocities, shear stress, pressure, and vorticity are discussed in conjunction with the bursting phenomenon detected by the VITA technique. The conditionally averaged pressure reveals that the ejection process is associated with a localized adverse pressure gradient. In the plane perpendicular to the flow direction, the conditionally averaged vorticity field indicates that a pair of counterrotating streamwise vorticity is being lifted through the ejection process.
Optimum maintenance policy using semi-Markov decision processes

A method is presented to solve for the optimum maintenance policy of repairable power equipment. A semi-Markov decision process (SMDP) is utilized to determine whether maintenance should be performed in each deterioration state and, if so, what type of maintenance. The approach uses a model that assumes equipment can fail due to both deterioration and random occurrences. Preventive maintenance can be performed from each working state to prevent deterioration failure. Minor maintenance will most likely return the equipment to the immediate preceding working state, while major maintenance can return the equipment to any of the previous working states. An example is used to demonstrate the method using MATLAB software.
The Structure of the Local Interstellar Medium. IV. Dynamics, Morphology, Physical Properties, and Implications of Cloud-Cloud Interactions*

We present an empirical dynamical model of the LISM based on 270 radial velocity measurements for 157 sight lines toward nearby stars. Physical parameter measurements (i.e., temperature, turbulent velocity, depletions) are availablefor90components,orone-thirdof thesample,enablinginitialcharacterizationsof thephysicalpropertiesof LISM clouds. The model includes 15 warm clouds located within 15 pc of the Sun, each with a different velocity vector. We derive projected morphologies of all clouds and estimate the volume filling factor of warm partially ionized material intheLISMtobebetween � 5.5%and 19%.Relative velocitiesof potentially interactingclouds areoftensupersonic, consistent with heating, turbulent, and metal depletion properties. Cloud-cloud collisions may be responsible for the filamentary morphologies found in � 1 of LISM clouds, the distribution of clouds along the boundaries of the two nearestclouds(LICandG),thedetailedshapeandheatingof theMicCloud,thelocationof nearbyradioscintillation screens, and the location of an LISM cold cloud. Contrary to previous claims, the Sun appears to be located in the transition zone between the LIC and G Cloud. Subject headingg ISM: atoms — ISM: clouds — ISM: structure — line: profiles — ultraviolet: ISM — ultraviolet: stars
On the moduli space of classical dynamical r-matrices

We define and study the moduli space of classical dynamical r-matrices associated to a Lie algebra g and a subalgebra l of g. As opposed to the previous papers q-alg/9703040 and q-alg/9706017 we do not make any commutativity assumption on the subalgebra l. We extend the notion of gauge-transformation to this setting and show that, under some technical conditions, the space of dynamical r-matrices modulo gauge-transformations is isomorphic to an explicitly given affine variety.
Instanton contribution to the proton and neutron electric form factors

Abstract We study the instanton contribution to the proton and neutron electric form factors. Using the single instanton approximation, we perform the calculations in a mixed time-momentum representation in order to obtain the form factors directly in momentum space. We find good agreement with the experimentally measured electric form factor of the proton. For the neutron, our result falls short of the experimental data. We argue that this discrepancy is due to the fact that we neglect the contribution of the sea quarks. We compare to lattice calculations and a relativistic version of the quark–diquark model.
Interpolating between $a$ and $F$

We study the dimensional continuation of the sphere free energy in conformal field theories. In continuous dimension d we define the quantity $$ \tilde{F} $$ =sin(πd/2) log Z, where Z is the path integral of the Euclidean CFT on the d-dimensional round sphere. $$ \tilde{F} $$ smoothly interpolates between (−1) d/2 π/2 times the a-anomaly coefficient in even d, and (−1)(d+1)/2 times the sphere free energy F in odd d. We calculate $$ \tilde{F} $$ in various examples of unitary CFT that can be continued to non-integer dimensions, including free theories, double-trace deformations at large N, and perturbative fixed points in the ϵ expansion. For all these examples $$ \tilde{F} $$ is positive, and it decreases under RG flow. Using perturbation theory in the coupling, we calculate $$ \tilde{F} $$ in the Wilson-Fisher fixed point of the O(N) vector model in d = 4 − ϵ to order ϵ 4. We use this result to estimate the value of F in the 3-dimensional Ising model, and find that it is only a few percent below F of the free conformally coupled scalar field. We use similar methods to estimate the F values for the U(N) Gross-Neveu model in d = 3 and the O(N) model in d = 5. Finally, we carry out the dimensional continuation of interacting theories with 4 supercharges, for which we suggest that $$ \tilde{F} $$ may be calculated exactly using an appropriate version of localization on S d . Our approach provides an interpolation between the a-maximization in d = 4 and the F-maximization in d = 3.
Effects of 6-hydroxydopa

Abstract After a single i.v. injection, 6-OHDOPA is capable of causing destruction and/or functional impairment of noradrenergic nerve terminals in both the central and the peripheral nervous system. By analogy with the effects of 6-hydroxydopamine and histochemical observations of preterminal accumulation of neurotransmitters, the conclusion that 6-OHDOPA causes degenerative changes in the terminal plexus is derived. There is no question that the final determination of neuronal degeneration should come from electron microscopic studies. The accumulation of histochemically observable catecholamine fluorescence in nonterminal axons, the time course of depletion and recovery of NE within various peripheral organs and impairment of uptake of exogenously administered NE support the conclusion that 6-OHDOPA has the potential to cause selective destruction of noradrenergic terminals. 6-OHDOPA is a valuable tool for the investigation of central pathways and functional organization of the noradrenergic neurons in the brain. Injection of 6-OHDOPA into the cerebral ventricles can produce a highly specific reduction in the NE content of the central nervous system while leaving dopaminergic neurons unaffected. This factor will be useful for the exploration of the behavioral contributions of central noradrenergic neurons.
The Effect of Private-Debt-Underwriting Reputation on Bank Public-Debt Underwriting

We provide evidence that commercial banks extend their reputation in underwriting syndicated loans and private placements (private debt) to their bond-underwriting activities. In the absence of bond market reputation, private-debt-market reputation enables commercial banks to win underwriting mandates from their loan clients. Furthermore, it allows them to credibly commit to investors against opportunistically using lending information and thereby deliver superior certification benefits in the form of higher issue prices relative to investment-bank underwriters. This pricing benefit is not offset by higher underwriting fees and thus results in lower total issuance costs for borrowers. (JEL G21, G28, L14, L15)
The Cosmic Density of Massive Black Holes from Galaxy Velocity Dispersions

Supermassive black holes are thought to be relics of quasars, and their numbers and masses are therefore related to the quasar luminosity function and its evolution with redshift. We have used the relationship between black hole mass and bulge velocity dispersion (the •-σ relation) to make an improved estimate of the mass density and mass spectrum of supermassive black holes. Uncertainties in the •-σ relation have little effect on the mass density. We find a mass density of (4.8 ± 1.6)h2 × 105 M⊙ Mpc-3. Some of the variance in published density estimates comes from the use of different values of the Hubble constant.
Winners and Losers as Financial Service Providers Converge: Evidence from the Financial Modernization Act of 1999

The Financial Modernization Act of 1999 dramatically increased insurers’ and investment banks’ authority to provide an array of financial services and allowed commercial banks to offer investment banking and insurance services. In this paper we examine the market response to this legislation. We find a strong positive response among insurance companies and investment banks, and no significant response among commercial banks. Larger institutions in all three financial sectors earn higher abnormal returns. Additionally, better performing banks earn higher abnormal returns. Our results suggest that allowing financial convergence can add value through synergies and that large players are needed to exploit the scope economies.
Selective nitration of styrenes with clayfen and clayan: A solvent-free synthesis of β-nitrostyrenes

Abstract A facile solvent-free synthesis of β-nitrostyrenes is described from styrene and its substituted derivatives using inexpensive ‘doped’ clay reagents, clayfen and clayan.
Torque Saturation in Bipedal Robotic Walking Through Control Lyapunov Function-Based Quadratic Programs

This paper presents a novel method to address the actuator saturation for nonlinear hybrid systems by directly incorporating user-defined input bounds in a controller design. In particular, we consider the application of bipedal walking and show that our method [based on a quadratic programming (QP) implementation of a control Lyapunov function (CLF)-based controller] enables a gradual performance degradation while still continuing to walk under increasingly stringent input bounds. We draw on our previous work, which has demonstrated the effectiveness of the CLF-based controllers for stabilizing periodic gaits for biped walkers. This paper presents a framework, which results in more effective handling of control saturations and provides a means for incorporating a whole family of user-defined constraints into the online computation of a CLF-based controller. This paper concludes with an experimental validation of the main results on the bipedal robot MABEL, demonstrating the usefulness of the QP-based CLF approach for real-time robotic control.
The exchange rate and macroeconomic determinants: Time-varying transitional dynamics

Abstract In this paper, I consider modeling the effects of the macroeconomic determinants on the nominal exchange rate to be channeled through the transition probabilities in a Markovian process. The model posits that the deviation of the exchange rate from its fundamental value alters the market's belief in the probability of the process staying in certain regime next period. This paper further takes into account the ARCH effects of the volatility of the exchange rate. Empirical results generally confirm that fundamentals can affect the evolution of the dynamics of the exchange rate in a nonlinear way through the transition probabilities. In addition, I find that the volatility of the exchange rate is associated with significant ARCH effects which are subject to regime changes.
Efficient algorithms for segmentation of item-set time series

We propose a special type of time series, which we call an item-set time series, to facilitate the temporal analysis of software version histories, email logs, stock market data, etc. In an item-set time series, each observed data value is a set of discrete items. We formalize the concept of an item-set time series and present efficient algorithms for segmenting a given item-set time series. Segmentation of a time series partitions the time series into a sequence of segments where each segment is constructed by combining consecutive time points of the time series. Each segment is associated with an item set that is computed from the item sets of the time points in that segment, using a function which we call a measure function. We then define a concept called the segment difference, which measures the difference between the item set of a segment and the item sets of the time points in that segment. The segment difference values are required to construct an optimal segmentation of the time series. We describe novel and efficient algorithms to compute segment difference values for each of the measure functions described in the paper. We outline a dynamic programming based scheme to construct an optimal segmentation of the given item-set time series. We use the item-set time series segmentation techniques to analyze the temporal content of three different data sets---Enron email, stock market data, and a synthetic data set. The experimental results show that an optimal segmentation of item-set time series data captures much more temporal content than a segmentation constructed based on the number of time points in each segment, without examining the item set data at the time points, and can be used to analyze different types of temporal data.
Scattering from General Periodic Screens

ABSTRACT This paper is intended as a short review of techniques for the analysis of planar periodic structures. Emphasis is directed toward the study of arbitrary surface geometries and the development of a framework suitable for combining surfaces with dielectric layers in the design of a screen. An outline of several essential properties of periodic surfaces is initially presented. A more detailed presentation of a technique with an iterative solution is then given with results directed toward structures with loss both in metal and dielectric.
Enantioselective organo-cascade catalysis.

A new strategy for organocatalysis based on the biochemical blueprints of biosynthesis has enabled a new laboratory approach to cascade catalysis. Imidazolidinone-based catalytic cycles, involving iminium and enamine activation, have been successfully combined to allow a large diversity of nucleophiles (furans, thiophenes, indoles, butenolides, hydride sources, tertiary amino lactone equivalents) and electrophiles (fluorinating and chlorinating reagents) to undergo sequential addition with a wide array of α,β-unsaturated aldehydes. These new cascade catalysis protocols allow the invention of enantioselective transformations that were previously unknown, including the asymmetric catalytic addition of the elements of HF across a trisubstituted olefin. Importantly, these domino catalysis protocols can be mediated by a single imidazolidinone catalyst or using cycle-specific amine catalysts. In the latter case, cascade catalysis pathways can be readily modulated to provide a required diastereo- and enantiosele...
Higher order time integration schemes for the unsteady Navier-Stokes equations on unstructured meshes

The efficiency gains obtained using higher-order implicit Runge-Kutta (RK) schemes as compared with the second-order accurate backward difference schemes for the unsteady Navier-Stokes equations are investigated. Three different algorithms for solving the nonlinear system of equations arising at each time step are presented. The first algorithm (nonlinear multigrid, NMG) is a pseudo-time-stepping scheme which employs a nonlinear full approximation storage (FAS) agglomeration multigrid method to accelerate convergence. The other two algorithms are based on inexact Newton's methods. The linear system arising at each Newton step is solved using iterative/Krylov techniques and left preconditioning is used to accelerate convergence of the linear solvers. One of the methods (LMG) uses Richardson's iterative scheme for solving the linear system at each Newton step while the other (PGMRES) uses the generalized minimal residual method. Results demonstrating the relative superiority of these Newton's method based schemes are presented. Efficiency gains as high as 10 are obtained by combining the higher-order time integration schemes such as fourth-order Runge-Kutta (RK64) with the more efficient inexact Newton's method based schemes (LMG).
Local Group Dwarf Galaxies and the Fundamental Manifold of Spheroids

The fundamental manifold (FM), an extension of the fundamental plane formalism, incorporates all spheroid-dominated stellar systems from dwarf ellipticals up to the intracluster stellar populations of galaxy clusters by accounting for the continuous variation of the mass-to-light ratio within the effective radius re with scale. Here we find that Local Group dwarf spheroidal and dwarf elliptical galaxies, which probe the FM relationship roughly one decade lower in re than previous work, lie on the extrapolation of the FM. When combined with the earlier data, these Local Group dwarfs demonstrate the validity of the empirical manifold over nearly 4 orders of magnitude in re. The continuity of the galaxy locus on the manifold and, more specifically, the overlap on the FM of dwarf ellipticals like M32 and dwarf spheroidals like Leo II, imply that dwarf spheroidals belong to the same family of spheroids as their more massive counterparts. The only significant outliers are Ursa Minor and Draco. We explore whether the deviation of these two galaxies from the manifold reflects a breakdown in the coherence of the empirical relationship at low luminosities or rather the individual dynamical peculiarities of these two objects. We discuss some implications of our results for how the lowest mass galaxies form.
A TWO-FLUID MODEL FOR ELECTRO- AND MAGNETORHEOLOGICAL SUSPENSIONS

A two-fluid continuum model is developed to describe mass transport in electro- and magnetorheological suspensions. The particle flux is related to the field-induced stresses. Solutions of the resulting mass balance show column formation in the absence of flow, and stripe formation when a suspension is subjected simultaneously to an applied electric field and shear flow.
[30]Heptaphyrin(1.1.1.1.1.0.0): an aromatic expanded porphyrin with a 'figure eight' like structure

The synthesis, characterization, and X-ray structure of a heptapyrrolic macrocycle, [30]heptaphyrin(1.1.1.1.1.0.0) is reported; despite showing aromatic features, it exhibits a ‘figure eight’-like structure in the solid state.
Self-dual effective action of N = 4 super-Yang-Mills

The full low-energy effective action of N = 4 SYM is believed to be self-dual. Starting with the first two leading terms in a momentum expansion of this effective action, we perform a duality transformation and find the conditions for self-duality. These determine some of the higher-order terms. We compare the effective action of N = 4 SYM with the probe-source description of type IIB D3-branes in the AdS5 × S5 background. We find agreement up to six derivative terms if we identify the separation of the 3-branes with a redefinition of the gauge scalar that involves the gauge field strength.
Job Rights in Russian Firms: Endangered or Extinct Institution?

Did the Soviet institution of job rights, guaranteed employment despite individual or firm performance, survive the initial stages of transition in the Russian economy? This paper employs survey data collected in 1992 and 1995 to evaluate the extent to which job rights continued to influence the behavior of firms and households three years after Russia inititated its reform program. Using a variety of measures, the results indicate that, while job rights might have been an endangered institution in 1995, the institution does not appear to have been rendered extinct.
Sequential Transformations to Access Polycyclic Chemotypes: Asymmetric Crotylation and Metal Carbenoid Reactions

The utility of a sequence consisting of organosilane-based carbonylation followed by Rh(II)-catalyzed asymmetric carbenoid transformation is demonstrated for the synthesis of different types of polycyclic heterocyclic frameworks such as (XI)-(XIV),.
Factors Affecting the Outcome of Exteriorized Colon Repairs

Of 32 penetrating colon injuries managed by repair and exteriorization during the past 5 years in 16 (50%) of the exteriorized repairs healed and 16 failed, being converted to colostomies. The overall morbidity was 25%, 19% for the healed anastomoses and 31% for those that failed. The two groups were similar with respect to age, location of injury, presence of shock, presence of associated injuries, and degree of fecal contamination. Significant differences were evident in the mechanism of trauma and the severity of tissue damage. Exteriorization of colon suture lines is a viable alternative in the management of penetrating colon injury. It should be employed primarily in cases where factors other than the tissue injury itself prohibit primary repair. The success of exteriorization can be improved by giving attention to technical details: adequate debridement; wide mobilization; keeping the repair moist; delaying return of the colon until the tenth postoperative day.
Building or Bypassing Recipient Country Systems: Are Donors Defying the Paris Declaration?

The 2005 Paris Declaration on Aid Effectiveness sets targets for increased use by donors of recipient country systems for managing aid. It also calls for donors to be more responsive to the quality of recipient country systems: the optimal level of their use, in terms of maximizing the development effectiveness of aid, is believed to vary with their quality. This study investigates the degree to which donors' use of country systems is in fact positively related to their quality, using indicators explicitly endorsed for this purpose by the Paris Declaration and covering the 2005-2010 period. The results of these tests strongly confirm a positive and significant relationship, and show it is robust to corrections for potential sample selection, omitted variables, or endogeneity bias. The result holds even when estimates are informed only by variation over time within each donor-recipient pair in use and quality of country systems. Moreover, donor-specific tests show that use of country systems varies positively with their quality for the vast majority of donors. These findings contradict several other studies that claim there is no relation and imply that donors in this respect are failing to live up to their commitments under the Paris Declaration. The author's interpretation of the available evidence on use of country systems is more favorable: donors' behavior over the measurement period is largely consistent with their commitments in this area. In this respect, at least, donors appear to have modified their aid practices in ways that build rather than undermine administrative capacity and accountability in recipient country governments.
Comparative assessment of alternative cycles for waste heat recovery and upgrade

Abstract Thermally activated systems based on sorption cycles, as well as mechanical systems based on vapor compression/expansion are assessed in this study for waste heat recovery applications. In particular, ammonia-water sorption cycles for cooling and mechanical work recovery, a heat transformer using lithium bromide-water as the working fluid pair to yield high temperature heat, and organic Rankine cycles using refrigerant R245fa for work recovery as well as versions directly coupled to a vapor compression cycle to yield cooling are analyzed with overall heat transfer conductances for heat exchangers that use similar approach temperature differences for each cycle. Two representative cases are considered, one for smaller-scale and lower temperature applications using waste heat at 60 °C, and the other for larger-scale and higher temperature waste heat at 120 °C. Comparative assessments of these cycles on the basis of efficiencies and system footprints guide the selection of waste heat recovery and upgrade systems for different applications and waste heat availabilities. Furthermore, these considerations are used to investigate four case studies for waste heat recovery for data centers, vehicles, and process plants, illustrating the utility and limitations of such solutions. The increased implementation of such waste heat recovery systems in a variety of applications will lead to decreased primary source inputs and sustainable energy utilization.
Self-organized Criticality in Compact Plasmas

Compact plasmas, which exist near black hole candidates and in gamma-ray burst sources, commonly exhibit self-organized nonlinear behavior. A model that simulates the nonlinear behavior of a compact radiative plasma is constructed directly from the observed luminosity and variability. The simulation shows that such a plasma self-organizes and that the degree of nonlinearity as well as the slope of the power density spectrum increases with compactness. The simulation is based on a cellular automaton table that includes the properties of the hot (relativistic) plasma and the magnitude of the energy perturbations. The plasma cools, or heats up, depending on whether it releases more or less energy than that of a single perturbation. The energy released depends on the plasma density and temperature and the energy of the perturbations. Strong perturbations may cool the previously heated plasma through shocks and/or pair creation. New observations of some active galactic nuclei and gamma-ray bursts are consistent with the simulation.
Point-to-Point Positioning of Flexible Structures Using a Time Domain LQ Smoothness Constraint

An analytical procedure to implement optimal smoothing of the finite-time control waveform for point-to-point control problem is presented, which minimizes an optimality constraint consisting of a linear combination of the quadratic norms of its time derivatives. It is shown that the resulting control input is essentially the minimum norm solution augmented to satisfy some additional continuity requirements in the time domain
Signal transmission across tile assemblies: 3D static tiles simulate active self-assembly by 2D signal-passing tiles

The 2-handed assembly model (2HAM) is a tile-based self-assembly model in which, typically beginning from single tiles, arbitrarily large aggregations of static tiles combine in pairs to form structures. The signal-passing tile assembly model (STAM) is an extension of the 2HAM in which the tiles are dynamically changing components which are able to alter their binding domains as they bind together. In this paper, we examine the $$\hbox {STAM}^+$$STAM+, a restriction of the STAM that does not allow glues to be turned "off", and prove that there exists a 3D tile set at temperature $$\tau >1$$?>1 in the 2HAM which is intrinsically universal for the class of all 2D $$\hbox {STAM}^+$$STAM+ systems at temperature $$\tau $$? for each $$\tau $$? (where the $$\hbox {STAM}^+$$STAM+ does not make use of the STAM's power of glue deactivation and assembly breaking, as the tile components of the 2HAM are static and unable to change or break bonds). This means that there is a single tile set $$U$$U in the 3D 2HAM which can, for an arbitrarily complex $$\hbox {STAM}^+$$STAM+ system $$S$$S, be configured with a single input configuration which causes $$U$$U to exactly simulate $$S$$S at a scale factor dependent upon $$S$$S. Furthermore, this simulation uses only two planes of the third dimension. This implies that there exists a 3D tile set at temperature $$2$$2 in the 2HAM which is intrinsically universal for the class of all 2D $$\hbox {STAM}^+$$STAM+ systems at temperature $$1$$1. Moreover, we also show that there exists an $$\hbox {STAM}^+$$STAM+ tile set for temperature $$\tau $$? which is intrinsically universal for the class of all 2D $$\hbox {STAM}^+$$STAM+ systems at temperature $$\tau $$?, including the case where $$\tau = 1$$?=1. To achieve these results, we also demonstrate useful techniques and transformations for converting an arbitrarily complex $$\hbox {STAM}^+$$STAM+ tile set into an $$\hbox {STAM}^+$$STAM+ tile set where every tile has a constant, low amount of complexity, in terms of the number and types of "signals" they can send, with a trade off in scale factor. While the first result is of more theoretical interest, showing the power of static tiles to simulate dynamic tiles when given one extra plane in 3D, the second result is of more practical interest for the experimental implementation of STAM tiles, since it provides potentially useful strategies for developing powerful STAM systems while keeping the complexity of individual tiles low, thus making them easier to physically implement.
Magnetic Accretion and Photopolarimetric Variability in T Tauri Stars

We investigate the photopolarimetric variability of a magnetic accretion disk model for pre-main-sequence T Tauri stars. In these dynamical models, material from a magnetically truncated Keplerian disk accretes along magnetic field lines onto the stellar surface at high latitudes, producing "hot spots" on the stellar photosphere. These spots have been proposed as the origin of the UV excesses in T Tauri stars. As the star rotates, the observed UV excess varies, as will the polarization arising from the intrinsically polarized spot the radiation of which is also scattered in the circumstellar disk. We calculate the photopolarimetric variability for a simple magnetic accretion model in which the hot spots are two diametrically opposed, circular regions with temperatures much larger than the surrounding photosphere. Our Monte Carlo calculations show that the predicted amplitudes of the photopolarimetric variability are consistent with those observed in T Tauri stars. This model predicts correlations between the brightness and polarization that can be tested with synoptic observations. The model also predicts quasi-periodic variations if the hot spots remain relatively fixed on the stellar surface on timescales comparable to the rotation period.
Synthesis and characterization of pendent hydroxy fluoroesters of secondary high molecular weight guayule rubber

The epoxidation of secondary high molecular weight guayule rubber (SHMWGR) and subsequent ring opening with fluoroacids to give hydroxyfluoroesters (FGR) is reported. Structural characterization was performed with FTIR; 1 H-, 13 C-, and 19 F-NMR; and DSC. The percent epoxidation was quantitatively determined by 1 H-NMR. It was noted that the glass transition temperatures (T g ) of the FGR polymers increased with increasing fluoro acid content; however, reactions with longer chain, highly fluorinated acids lowered the T g .
The Sepulveda GEU Study revisited: Long-term outcomes, use of services, and costs

The randomized controlled trial of the Geriatric Evaluation Unit (GEU) at the Sepulveda Veterans Hospital was the first to document the clinical and cost-effectiveness of hospital-based comprehensive geriatric assessment (CGA). Frail elderly inpatients were assigned randomly to the GEU for CGA, therapy, rehabilitation, and placement (N=63), or to standard hospital care (N=60). At one year, GEU patients had much lower mortality (24% vs 48%) and were less likely to have been discharged to a nursing home (NH) (13% vs 30%), or to have spent any time in NHs (27% vs 47%). GEU patients were more likely to improve in personal self-maintenance and morale. Further, controls had substantially more acute-care hospital days, NH days, and hospital readmissions, resulting in higher direct institutional care costs, especially after survival adjustment. Here, we report the results of long-term follow-up. There was a significant survival effect through two years. Despite prolongation of life, there was no indication that quality of life was worse for survivors in the GEU group. In fact, the proportion of persons independent in ⩾2 ADLs at two years was somewhat higher for GEU patients (0.44) than controls (0.33) (z=1.27; p=0.056). By three years, 43% of GEU subjects and 38% of controls were still alive. Over the entire 3-year period, the per capita direct cost difference was not significant, either before or after survival adjustment (unadjusted: $37,091 GEU vs $34,205 control; survival-adjusted: $54,315 GEU vs $63,362 control; p=0.17). For patients who died during follow-up, the per capita health-care costs of the last year of life were significantly lower in GEU than control decedents ($28,337 vs $38,494; p=0.01). We conclude that the beneficial effects of the GEU persisted at least to 2 years, and that GEU and associated aftercare did not inflate care costs and was ost-effective over the long term. (Aging Clin. Exp. Res. 7: 212-217, 1995)
A geometric view of quantum cellular automata

Nielsen, et al.1, 2 proposed a view of quantum computation where determining optimal algorithms is equivalent to extremizing a geodesic length or cost functional. This view of optimization is highly suggestive of an action principle of the space of N-qubits interacting via local operations. The cost or action functional is given by the cost of evolution operators on local qubit operations leading to causal dynamics, as in Blute et. al.3 Here we propose a view of information geometry for quantum algorithms where the inherent causal structure determines topology and information distances4, 5 set the local geometry. This naturally leads to geometric characterization of hypersurfaces in a quantum cellular automaton. While in standard quantum circuit representations the connections between individual qubits, i.e. the topology, for hypersurfaces will be dynamic, quantum cellular automata have readily identifiable static hypersurface topologies determined via the quantum update rules. We demonstrate construction of quantum cellular automata geometry and discuss the utility of this approach for tracking entanglement and algorithm optimization.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Foreign Language Teacher Training in the Sudan: Past, Present and Strategies for Future Recruitment Policies

The qualifying of teachers secures the attainment of the national educational objectives, but to achieve these goals, strict criteria about teacher quality must be utilized. However, it is quite clear that whatever measures are to be adopted to deal with these educational issues, it is always the teachers who will have to put these objectvies into reality.This paper is suggesting some ideas to improve the teaching profession. The recent recruitment policy of teachers in the country attracts only the poor achievers, who are unwilling to teach but they aspire to just get a degree. This paper suggests abolishing all colleges of education and encouraging the future teacher to join a one-year training course after s/he has got his/her BA or B.Sc. This policy will attract the willing persons who are serious to take teaching as their profession. Then the candidates can spend this one academic year to be equipped with necessary pedagogical knowledge to qualify to manage his/her classroom efficiently and carry out effective classroom presentation. By this recruitment policy, we can guarantee the sustainability of the process, and that only the willing persons will come to take teaching as their future career.
A Catalog of Star Cluster Candidates in M33

We present a new catalog of star cluster candidates in the nearby spiral galaxy M33. It is based on eight existing catalogs wherein we have cross-referenced identifications and endeavored to resolve inconsistencies between them. Our catalog contains 451 candidates, of which 255 are confirmed clusters based on Hubble Space Telescope and high-resolution ground-based imaging. The catalog contains precise cluster positions (right ascension and declination), magnitudes and colors in the UBVRIJHKS filters, metallicities, radial velocities, masses and ages, where available, and galactocentric distances for each cluster. The color distribution of the M33 clusters appears to be similar to those in the Large Magellanic Cloud, with major peaks at (B - V)0 ~ 0.15 and (B - V)0 ~ 0.65. The intrinsic colors are correlated with cluster ages, which range from 107.5 to 1010.3 yr. The age distribution of the star clusters supports the notion of rapid cluster disruption with a slope of α = -1.09 ± 0.07 in the dNclus/dτ ∝ τα relation. In addition, comparison to theoretical single stellar population models suggests the presence of an age-metallicity relation among these clusters, with younger clusters being more metal-rich. Analysis of the radial distribution of the clusters yields some evidence that younger clusters (age 1 Gyr) may be more concentrated toward the center of M33 than older ones. A similar comparison with the radial profile of the M33 field stars shows the clusters to be more centrally concentrated at the greater than 99.9% confidence level. Possible reasons for this are presented and discussed; however, the overwhelming conclusion seems to be that a more complete and thorough cluster search is needed, covering at least 4 deg2 centered on M33.
The Least-Perimeter Partition of a Sphere into Four Equal Areas

We prove that the least-perimeter partition of the sphere into four regions of equal area is a tetrahedral partition.
An approach to the synthesis of tricholomalide A: an effective means for achieving homo-Robinson annulation

A procedure has been developed for the construction of 7,5-fused ring systems through the ring expansion of silyl enol ethers. This method has been applied to the synthesis of an intermediate en route to the natural product, tricholomalide A.
Persistence of gaps in the spectrum of certain almost periodic operators

It is shown that for any irrational rotation number and any admissible gap labelling number the almost Mathieu operator (also known as Harper’s operator) has a gap in its spectrum with that labelling number. This answers the strong version of the so-called "Ten Martini Problem". When specialized to the particular case where the coupling constant is equal to one, it follows that the "Hofstadter butterfly" has for any quantum Hall conductance the exact number of components prescribed by the recursive scheme to build this fractal structure.