cssi/SciSciGPT-SciSciNet huggingface dataset:
The importance of nutritional factors in the pathogenesis of iron deficiency anemia.

(1957). The Importance of Nutritional Factors in the Pathogenesis of Iron Deficiency Anemia. Scandinavian Journal of Clinical and Laboratory Investigation: Vol. 9, No. 3, pp. 292-304.
Class one graphs

Abstract Conditions on the subgraph induced by the vertices of maximum degree of a simple graph G are found which are sufficient for G to be class 1. These conditions can be used to generalize a result of Fournier. An efficient algorithm is described for deciding whether or not a particular graph satisfies the conditions.
A modal analysis of staged computation

We show that a type system based on the intuitionistic modal logic S4 provides an expressive framework for specifying and analyzing computation stages in the context of typed λ-calculi and functional languages. We directly demonstrate the sense in which our λe→□-calculus captures staging, and also give a conservative embeddng of Nielson and Nielson's two-level functional language in our functional language Mini-ML□, thus proving that binding-time correctness is equivalent to modal correctness on this fragment. In addition, Mini-ML□ can also express immediate evaluation and sharing of code across multiple stages, thus supporting run-time code generation as well as partial evaluation.
Antisymmetric and other subleading corrections to scaling in the local potential approximation

Abstract For systems in the universality class of the three-dimensional Ising model we compute the critical exponents in the local potential approximation (LPA), that is, in the framework of the Wegner–Houghton equation. We are mostly interested in antisymmetric corrections to scaling, which are relatively poorly studied. We find the exponent for the leading antisymmetric correction to scaling ω A ≈1.691 in the LPA. This high value implies that such corrections cannot explain asymmetries observed in some Monte Carlo simulations.
ASSESSING AND COMMUNICATING SOCIAL SCIENCE INFORMATION IN FAMILY AND CHILD JUDICIAL SETTINGS: STANDARDS FOR JUDGES AND ALLIED PROFESSIONALS

Social science is increasingly important in judicial decision making and family law development. This increased use means that judges, lawyers, mental health professionals, and social scientists must assess the quality of social science information and communicate it in a multidisciplinary environment. This article provides tools for improving multidisciplinary communication by identifying logical, methodological, and community standards for assessment and communication that are fundamental both to the scientific method and to the inquiries the Daubert decision instructs judges to make in their gatekeeper evaluations of scientific information. Employing a common set of standards can result in a significant improvement in the quality of the social science knowledge used in judicial settings.
Thermoelectric properties and electronic structure calculations of low thermal conductivity Zintl phase series M16X11 (M = Ca and Yb; X = Sb and Bi)

Abstract Zintl phases of type M 16 X 11 (M = Ca and Yb; X = Sb and Bi) have been synthesized by both the flux or solid state reaction methods. In order to evaluate the potential of these phases for thermoelectrics, the electrical resistivity ( ρ ), thermopower ( α ) and thermal conductivity ( κ ) have been measured on hot pressed samples over a wide temperature range of 10–1000 K. The ρ and α trends are typical of a degenerate semiconductor. However, α remains low (∼30 μV/K or less). Hall measurements indicate a rather low charge carrier mobility ∼3–7 cm 2 /V s, except for Ca 16 Sb 11 . It is notable that low thermal conductivity values ranging from ∼2.5 to 0.8 W/m K are measured for these phases at higher temperatures up to 1273 K. Particularly for Yb 16 Sb 11 , the lattice part of thermal conductivity is found to be between 0.5 and 0.7 W/m K. However, the challenge in this M 16 X 11 system is to achieve high thermopower. In order to understand more fully the measured transport properties, band structure calculations have been performed. Consistent with experimental data, these calculations suggest that all the systems are indeed metallic. The electronic structures for Ca-based phases show one dimensional metallic behavior with small and almost symmetric density of states around the Fermi level.
Large deviations for the growth rate of the support of supercritical super-Brownian motion

We prove a large deviation result for the growth rate of the support of the d-dimensional (strictly dyadic) branching Brownian motion Z and the d-dimensional (supercritical) super-Brownian motion X. We show that the probability that Z(X) remains in a smaller than typical ball up to time t is exponentially small in t and we compute the cost function. The cost function turns out to be the same for Z and X. In the proof we use a decomposition result due to Evans and O'Connell and elementary probabilistic arguments. Our method also provides a short alternative proof for the lower estimate of the large time growth rate of the support of X, first obtained by Pinsky by pde methods.
Dividend taxes and firm valuation:: a re-examination

Abstract Harris and Kemsley (J. Account. Res. (1999) 275) suggest that shareholder-level dividend taxes on retained earnings are fully impounded into stock prices at the top statutory rate. Harris and Kemsley base their empirical tests on Ohlson (Contemp. Account. Res. (1995) 661) with the addition of dividend taxes. We analyze Harris and Kemsley's extended Ohlson model and evidence. We show that the model, tests, and results in Harris and Kemsley are non-diagnostic regarding dividend tax capitalization.
Time-gating processes in intra-cavity mode-locking devices like saturable absorbers and Kerr cells

Photons are non-interacting entities. Light beams do not interfere by themselves. Light beams constituting different laser modes (frequencies) are not capable of re-arranging their energies from extended time-domain to ultra-short time-domain by themselves without the aid of light-matter interactions with suitable intra-cavity devices. In this paper we will discuss the time-gating properties of intra-cavity "mode-locking" devices that actually help generate a regular train of high energy wave packets.
Modular and orthogonal synthesis of hybrid polymers and networks

Biomaterials scientists strive to develop polymeric materials with distinct chemical make-up, complex molecular architectures, robust mechanical properties and defined biological functions by drawing inspirations from biological systems. Salient features of biological designs include (1) repetitive presentation of basic motifs; and (2) efficient integration of diverse building blocks. Thus, an appealing approach to biomaterials synthesis is to combine synthetic and natural building blocks in a modular fashion employing novel chemical methods. Over the past decade, orthogonal chemistries have become powerful enabling tools for the modular synthesis of advanced biomaterials. These reactions require building blocks with complementary functionalities, occur under mild conditions in the presence of biological molecules and living cells and proceed with high yield and exceptional selectivity. These chemistries have facilitated the construction of complex polymers and networks in a step-growth fashion, allowing facile modulation of materials properties by simple variations of the building blocks. In this review, we first summarize features of several types of orthogonal chemistries. We then discuss recent progress in the synthesis of step growth linear polymers, dendrimers and networks that find application in drug delivery, 3D cell culture and tissue engineering. Overall, orthogonal reactions and modulular synthesis have not only minimized the steps needed for the desired chemical transformations but also maximized the diversity and functionality of the final products. The modular nature of the design, combined with the potential synergistic effect of the hybrid system, will likely result in novel hydrogel matrices with robust structures and defined functions.
Microenvironment-induced downregulation of miR-193b drives ovarian cancer metastasis

The cross-talk between ovarian cancer (OvCa) cells and the metastatic microenvironment is an essential determinant of successful colonization. MicroRNAs (miRNAs) have several critical roles during metastasis; however, the role of microenvironmental cues in the regulation of miRNAs in metastasizing cancer cells has not been studied. Using a three-dimensional culture model that mimics the human omentum, one of the principal sites of OvCa metastasis, we identified and characterized the microenvironment-induced downregulation of a tumor suppressor miRNA, miR-193b, in metastasizing OvCa cells. The direct interaction of the OvCa cells with mesothelial cells, which cover the surface of the omentum, caused a DNA methyltransferase 1-mediated decrease in the expression of miR-193b in the cancer cells. The reduction in miR-193b enabled the metastasizing cancer cells to invade and proliferate into human omental pieces ex vivo and into the omentum of a mouse xenograft model of OvCa metastasis. The functional effects of miR-193b were mediated, in large part, by the concomitant increased expression of its target, urokinase-type plasminogen activator, a known tumor-associated protease. These findings link paracrine signals from the microenvironment to the regulation of a key miRNA in cancer cells. Targeting miR-193b, which is essential for metastatic colonization of cancer cells could prove effective in the treatment of OvCa metastasis.
Black-hole masses from reverberation mapping

Abstract We review briefly how black hole masses are measured directly using reverberation mapping and indirectly through scaling relationships based on reverberation results, in particular through broad-line region radius–luminosity relationships. We discuss the nature and origin of uncertainties in these measurements, and outline current and future efforts directed towards reducing these uncertainties.
Application of a phase transfer reaction to the synthesis of l-fructose

Abstract l -Fructose was prepared in five steps from l -sorbose (1). 1,2-O- Isopropylidene-α- l -sorbopyranose (2), prepared from 1, was selectively tosylated using phase transfer catalysis to give 1,2-O- isopropylidene -3-O-(p- tolylsulfonyl)-α- l -sorbopyranose (3). Formation of a 3,4-anhydro ring, followed by its base-catalyzed opening to effect overall inversion of configuration at both C-3 and C-4 gave 1,2-O- isopropylidene-α- l -fructopyranose (5), which was deacetonated to yield l -fructose (6).
The impact of multiuser virtual environments on student engagement

Abstract The purpose of this pilot study was to test the hypothesis that web-based synchronous instruction utilizing Multi-user Virtual World Environments (MUVEs) increases student engagement compared to traditional asynchronous learning methods. In a quasi-experimental two group posttest only study, a sample of Family Nurse Practitioner students ( n = 21) received instruction using either a synchronous ( n = 10) or asynchronous ( n = 11) learning method. Engagement was measured using the Community of Inquiry survey. Results indicated that engagement scores were significantly higher for the synchronous learning platform (mean = 3.61, SD = 1.13) compared to the asynchronous learning platform (mean = 3.49, SD = 1.08, t (1766) = −2.21, p
Palladium-catalyzed C–N and C–C cross-couplings as versatile, new avenues for modifications of purine 2′-deoxynucleosides

Abstract Methods involving palladium-catalysis can be efficiently applied to the relatively labile purine 2′-deoxynucleosidic systems. The net result is the remarkably ready access to new and unusual 2′-deoxyribonucleoside analogs bearing subsitutents on the purine moiety. C–N cross-coupling reactions are particularly attractive for the synthesis of N6 and N2 substituted 2′-deoxyadenosines and 2′-deoxyguanosines, respectively, as well as C-8 modified 2′-deoxyguanosines. CC bond-formation on the other hand, provides access to nucleosides containing hydrophobic hydrocarbon entities. Although the common theme for C–N and C–C cross-coupling is catalysis by Pd, there are substantial differences between the two classes of reactions. Furthermore, there are pronounced differences in reactivity trends at the C-6 position compared to those at the C-2. Optimized reaction conditions for both varieties of transformations can be found whereby novel purine 2′-deoxynucleosides can be readily obtained.
Distribution free evolvability of polynomial functions over all convex loss functions

We formulate a notion of evolvability for functions with domain and range that are real-valued vectors, a compelling way of expressing many natural biological processes. We show that linear and fixed-degree polynomial functions are evolvable in the following dually robust sense: There is a single evolution algorithm that for all convex loss functions converges for all distributions.It is possible that such dually robust results can be achieved by simpler and more natural evolution algorithms. In the second part of the paper we introduce a simple and natural algorithm that we call "wide-scale random noise" and prove a corresponding result for the L2 metric. We conjecture that the algorithm works for more general classes of metrics.
On the diurnal variation of the potential gradient of atmospheric electricity

Two years ago the author read before this section a paper giving the results of an analysis based upon all the diurnal-variation observations for potential gradient, conforming to an adopted standard, which had then been made aboard the Carnegie. It may be recalled that when the observations for the Atlantic, Pacific, and Indian Oceans, respectively, were tabulated in the usual manner, according to the local time of observation, the mean curves showed the diurnal variation over each of the oceans to consist almost entirely of a well-defined 24-hour wave although the times of occurrence of, say, the maximum phase of this wave differed greatly for the several oceans. It was also shown that mean curves, for the several oceans, obtained after first referring each series of observations to G.M.T. indicated a roughly simultaneous occurrence of maximum and of minimum, respectively, over all the accessible ocean areas. It was further shown that the mean diurnal-variation curves from many leading observatories, especially those corresponding to high latitudes and to winter months in the Northern Hemisphere, were in better agreement when plotted according to G.M.T. than according to local time.
Current observational constraints on cosmic doomsday

In a broad class of dark energy models, the universe may collapse within a finite time tc. Here we study a representative model of dark energy with a linear potential, V () = V0(1+α). This model is the simplest doomsday model, in which the universe collapses rather quickly after it stops expanding. Observational data from type Ia supernovae (SNe Ia), cosmic microwave background anisotropy (CMB), and large scale structure (LSS) are complementary in constraining dark energy models. Using the new SN Ia data (the Riess sample), the CMB data from WMAP, and the LSS data from 2dF, we find that the collapse time of the universe is (24) Gyr from today at 68% (95%) confidence.
Relative rate profile for ring-closing metathesis of a series of 1-substituted 1,7-octadienes as promoted by a 4,5-dihydroimidazol-2-ylidene-coordinated ruthenium catalyst.

This report details the kinetic responses of nine compounds of type 6 to ring-closing metathesis as promoted by 2 to give the identical product 7. The experimental observations have been subjected to Hammett analysis. The ρ value for the composite aromatic derivatives (R = p-XC6H4−) differs from that of the aliphatic series, although both are negative because electron-donating groups accelerate the reaction.
Do Liars Believe? Beliefs And Other-Regarding Preferences In Sender-Receiver Games

Abstract We examine subjects’ behavior in sender–receiver games where there are gains from trade and alignment of interests in one of the two states. We elicit subjects’ beliefs, risk and other-regarding preferences. Our design also allows us to examine the behavior of subjects in both roles, to determine whether the behavior in one role is the best response to the subject's own behavior in the other role. The results of the experiment indicate that, when acting as senders, the majority of subjects adopt deceptive strategies by sending favorable message when the true state of the nature is unfavorable. When acting as receivers, the majority of subjects invest conditional upon receiving a favorable message. The investing behavior of receivers cannot be explained by risk preferences or as a best response to subject's own behavior in the sender's role. However, it can be rationalized by accounting for elicited beliefs and other-regarding preferences. Finally, the honest behavior of some senders can be explained by other-regarding preferences. Thus, we that find liars do believe, and that individuals who care about the payoffs of others tend to be honest.
Daubert, cognitive malingering, and test accuracy.

Daubert v. Merrell Dow Pharmaceuticals (1993) held that trial judges should permit expert scientific testimony only when "the reasoning or methodology underlying the testimony is scientifically valid, and ... properly can be applied to the facts in issue." Vallabhajosula and van Gorp ("V & vG," 2001) have suggested that when the Daubert standard is applied to tests for malingered cognitive deficits, courts should deem admissible only results that meet this mathematical standard: assuming a pretest probability of .3, a "positive" score on the malingering test should yield a posttest probability of at least .8. This paper shows that V & vG's criterion may lead to misunderstandings about the kind of information maligering measures provide. After reviewing cases that have discussed both the Daubert decision and malingered cognitive deficits, this paper uses data from the Test of Memory Malingering (T.N. Tombaugh, 1996) to provide a general characterization of the mathematical properties of malingering measures. The paper then describes how pretest knowledge about malingering is combined with knowledge about a test's performance to generate a posttest probability of malingering. The results can help mental health experts respond to Daubert-inspired challenges to conclusions based on malingering measures.
QCD, Symmetry Breaking and the Random Lattice

According to the Nielsen-Ninomiya No-Go theorem, the doubling of fermions on the lattice cannot be suppressed in a chiral theory. Whereas Wilson and staggered fermions suppress doublers with explicit breaking of chiral symmetry, the random lattice does so by spontaneous chiral symmetry breaking even in the free theory. I present results for meson masses, the chiral condensate and fermionic eigenvalues from simulations of quenched QCD on random lattices in four dimensions, focusing on chiral symmetry breaking.
The Interaction of Value and Momentum Strategies

Value and momentum strategies both have demonstrated power to predict the crosssection of stock returns, but are these strategies related? Measures of momentum and value are negatively correlated across stocks, yet each is positively related to the cross-section of average stock returns. We examine whether the marginal power of value or momentum differs depending upon the level of the other variable. Value strategies work, in general, but are strongest among low-momentum (loser) stocks and weakest among high-momentum (winner) stocks. The momentum strategy works, in general, but is particularly strong among low-value (expensive) stocks. These results hold despite finding comparable spreads in value measures among stocks with different levels of momentum and comparable spreads in the momentum measure among stocks with different levels of value. Any explanation for why value and momentum work must explain this interaction.
Analysis of spatial pseudodepolarizers in imaging systems

The objective of a number of optical instruments is to measure the intensity accurately without bias as to the incident polarization state. One method to overcome polarization bias in optical systems is the insertion of a spatial pseudodepolarizer. Both the degree of depolarization and image degradation (from the polarization aberrations of the pseudodepolarizer) are analyzed for two depolarizer designs: (1) the Cornu pseudodepolarizer, effective for linearly polarized light, and (2) the dual Babinet compensator pseudodepolarizer, effective for all incident polarization states. The image analysis uses a matrix formalism to describe the polarization dependence of the diffraction patterns and optical transfer function.
Modified Basis Pursuit Denoising(modified-BPDN) for noisy compressive sensing with partially known support

In this work, we study the problem of reconstructing a sparse signal from a limited number of linear ‘incoherent’ noisy measurements, when a part of its support is known. The known part of the support may be available from prior knowledge or from the previous time instant (in applications requiring recursive reconstruction of a time sequence of sparse signals, e.g. dynamic MRI). We study a modification of Basis Pursuit Denoising (BPDN) and bound its reconstruction error. A key feature of our work is that the bounds that we obtain are computable. Hence, we are able to use Monte Carlo to study their average behavior as the size of the unknown support increases. We also demonstrate that when the unknown support size is small, modified-BPDN bounds are much tighter than those for BPDN, and hold under much weaker sufficient conditions (require fewer measurements).
Novel Blind Identification of LDPC Codes Using Average LLR of Syndrome a Posteriori Probability

Blind signal processing methods have been very popular recently since they can play crucial roles in the prevalent cognitive radio research. Blind encoder identification has drawn research interest lately. In this paper, we would like to tackle the blind identification of binary low-density parity-check (LDPC) codes for binary phase-shift keying (BPSK) signals. We propose a novel blind identification system which consists of three components, namely expectation-maximization (EM) estimator for signal amplitude and noise variance, log-likelihood ratio (LLR) estimator for syndrome a posteriori probabilities, and maximum average LLR detector. Monte Carlo simulation results demonstrate that our proposed blind LDPC encoder identification scheme is very promising even for low signal-to-noise ratio conditions.
Extra observables in gauged WZW models

It is known that Liouville theory can be presented as an SL(2, R) gauged WZW model. We study a two-dimensional field theory which can be obtained by analytically continuing some of the variables in the SL(2, R) gauged WZW model. We can derive Liouville theory from the analytically continued model, (which is gauged SL(2, C/SU(2) model,) in a similar but more rigorous way than from the original gauged WZW model. We investigate the obsevables of this gauged SL(2, C)/SU(2) model. We find infinitely many extra observables which can not be identified with operators in Liouville theory. We concentrate on observables which are (1, 1) forms and the correlators of their integralsover two-dimensional spacetime. At a special value of the coupling constant of our model, the correlators of these integrals on the sphere coincide with the results from matrix models.
Zyzzyva: Speculative Byzantine fault tolerance

A longstanding vision in distributed systems is to build reliable systems from unreliable components. An enticing formulation of this vision is Byzantine Fault-Tolerant (BFT) state machine replication, in which a group of servers collectively act as a correct server even if some of the servers misbehave or malfunction in arbitrary (“Byzantine”) ways. Despite this promise, practitioners hesitate to deploy BFT systems, at least partly because of the perception that BFT must impose high overheads.In this article, we present Zyzzyva, a protocol that uses speculation to reduce the cost of BFT replication. In Zyzzyva, replicas reply to a client's request without first running an expensive three-phase commit protocol to agree on the order to process requests. Instead, they optimistically adopt the order proposed by a primary server, process the request, and reply immediately to the client. If the primary is faulty, replicas can become temporarily inconsistent with one another, but clients detect inconsistencies, help correct replicas converge on a single total ordering of requests, and only rely on responses that are consistent with this total order. This approach allows Zyzzyva to reduce replication overheads to near their theoretical minima and to achieve throughputs of tens of thousands of requests per second, making BFT replication practical for a broad range of demanding services.
Stereospecific synthesis of 2-substituted bicyclic thiazolidine lactams

Abstract Bicyclic thiazolidine lactam 1 was used as a model system for developing synthetic methodology into β-turn mimics that would contain side chain functionality. treatment of a mixture of 1 and a non-enolizable aldehyde at −100 °C with LDA resulted in a good yield of the aldol adduct when aromatic aldehydes were used. Radical dehydroxylation of the pentafluorophenylcarbonate derivative of the aldol adduct with ( n -Bu) 3 SnH and AIBN gave a single isomer of the C-2 alkylated bicyclic 5,5-thiazolidine lactam. This methodology was applied to the synthesis of the 2-substituted spiro bicyclic thiazolidine lactam type II' β-turn mimic 14 .
PREPARATION OF THE ZARAGOZIC ACID CORE THROUGH THE REARRANGEMENT OF AN OXONIUM YLIDE

Abstract The diastereoselective formation of a 2,8-dioxabicyclo[3.2.1]octane skeleton was accomplished through the generation and rearrangement of a bicyclic oxonium ylide. The skeleton which was formed is common to the zaragozic acid family and possesses appropriate functionality for further manipulation. The study also revealed the first example of an exocyclic 2,3-shift from a acetal-derived oxonium ylide.
Effect of cluster formation on isospin asymmetry in the liquid-gas phase transition region

Nuclear matter within the liquid-gas phase transition region is investigated in a mean-field two-component Fermi-gas model. Following largely analytic considerations, it is shown that: 1) Due to the density dependence of asymmetry energy, some of the neutron excess from the high-density phase could be expelled into the low-density region. 2) Formation of clusters in the gas phase tends to counteract this trend, making the gas phase more liquid-like and reducing the asymmetry in the gas phase. Flow of asymmetry between the spectator and midrapidity region in reactions is discussed and a possible inversion of the flow direction is indicated.
Paramagnons, weak disorder and positive giant magnetoresistance

At low temperature and for finite spin scattering in a weakly disordered metal, for a certain value, predicted from our theory, of the material-dependent paramagnon interaction, the total conductivity becomes highly sensitive to the orbital effects of a finite magnetic field. As a consequence, positive giant magnetoresistance and giant corrections to the Hall coefficient arise. We obtain very good agreement between this theory and recent positive giant magnetoresistance experiments.
Time-dependent density-functional-theory calculation of strong-field ionization rates of H 2

We report a numerical study of strong-field ionization rates of the H{sub 2} molecule using time-dependent density-functional theory (TDDFT). In the dc field limit, TDDFT results for the rate of tunneling ionization agree with molecular Ammosov-Delone-Kralnov (MO-ADK) predictions, as well as results from a complex scaling method at the full configuration interaction level. Our study demonstrates the effect of photon energy, molecular vibration, and orientation on the ionization. Calculated rates for 800-nm lasers are about four times greater than the values predicted by the slowly varying field approximation for tunneling ionization. The rate for the ground vibrational state is higher than that of the fixed nuclei value at the equilibrium distance. This difference decreases with increasing field intensity. When the field intensity is sufficiently high, the two rates are very similar, and the fixed nuclear distance rate may be used to approximate the ground-vibrational-state rate. TDDFT methods predict an anisotropy slightly larger than the prediction obtained from the MO-ADK method. We also find that the field intensity plays a role in the anisotropy, which the MO-ADK results do not show.
Approximation of Range in Materials as a Function of Incident Electron Energy

A simple composite analytic expression has been developed to approximate the electron range in materials. The expression is applicable over more than six orders of magnitude in energy ( ; MeV) and range ( 10-9-10-2 m), with an uncertainty of ≤ 20% for most conducting, semiconducting, and insulating materials. This is accomplished by fitting data from two standard NIST databases [ESTAR for the higher energy range and the electron inelastic mean free path (IMFP) for the lower energies]. In turn, these data have been fit with well-established semiempirical models for range and IMFP that are related to standard material properties (e.g., density, atomic number, atomic weight, stoichiometry, and bandgap energy). Simple relations between the IMFP and the range, based on the continuous-slow-down approximation, are used to merge results from the two databases into a composite range expression. A single free parameter, termed the effective number of valence electrons per atom Nv, is used to predict the range over the entire energy span.
Shared knowledge in computational fluid dynamics, electromagnetics, and magneto-aerodynamics

Abstract The rich heritage of computational fluid dynamics (CFD) has provided an in-depth knowledge for computational electromagnetics, computational magneto-aerodynamics, and multidisciplinary technology development in aerospace science. Current progress in these developing disciplines and their roots in CFD are detailed. Highlights of the frontier expanding potential for CFD by combining aerodynamics, electromagnetics, and chemical kinetics for aerospace science are also presented.
Syntheses of Cyclic Guanidine-Containing Natural Products

Naturally occurring guanidine derivatives frequently display medicinally useful properties. Among them, the higher order pyrrole-imidazole alkaloids, the dragmacidins, the crambescidins/batzelladines, and the saxitoxins/tetradotoxins have stimulated the development of many new synthetic methods over the past decades. We provide here an overview of the syntheses of these cyclic guanidine-containing natural products.
FINITE TYPE LINK CONCORDANCE INVARIANTS

This paper is a follow-up to [10], in which the author showed that the only real-valued finite type invariants of link homotopy are the linking numbers of the components. In this paper, we extend the methods used to show that the only real-valued finite type invariants of link concordance are, again, the linking numbers of the components.
Data gathering in networks of bacteria colonies: Collective sensing and relaying using molecular communication

The prospect of new biological and industrial applications that require communication in micro-scale, encourages research on the design of bio-compatible communication networks using networking primitives already available in nature. One of the most promising candidates for constructing such networks is to adapt and engineer specific types of bacteria that are capable of sensing, actuation, and above all, communication with each other. In this paper, we describe a new architecture for networks of bacteria to form a data collecting network, as in traditional sensor networks. The key to this architecture is the fact that the node in the network itself is a bacterial colony; as an individual bacterium (biological agent) is a tiny unreliable element with limited capabilities. We describe such a network under two different scenarios. We study the data gathering (sensing and multihop communication) scenario as in sensor networks followed by the consensus problem in a multinode network. We will explain as to how the bacteria in the colony collectively orchestrate their actions as a node to perform sensing and relaying tasks that would not be possible (at least reliably) by an individual bacterium. Each single bacterium in the colony forms a belief by sensing external parameter (e.g., a molecular signal from another node) from the medium and shares its belief with other bacteria in the colony. Then, after some interactions, all the bacteria in the colony form a common belief and act as a single node. We will model the reception process of each individual bacteria and will study its impact on the overall functionality of a node. We will present results on the reliability of the multihop communication for data gathering scenario as well as the speed of convergence in the consensus scenario.
Considerations for Automated Nap-of-the-Earth Rotorcraft Flight

In this paper, we consider nap-of-the-earth (NOE) rotorcraft flight as one of the applications in which obstacle avoidance plays a key role, and investigate the prospects of automating the guidance functions of NOE flight. Based on a proposed structure for the guidance functions, we identify obstacle detection and obstacle avoidance as the two critical components requiring substantial advancement before an automatic guidance system can be realized. We discuss the major sources of difficulties in developing these two components, including sensor requirements for which we provide a systematic analysis.
Towards imperative modules: reasoning about invariants and sharing of mutable state

Imperative and object-oriented programs make ubiquitous use of shared mutable objects. Updating a shared object can and often does transgress a boundary that was supposed to be established using static constructs such as a class with private fields. This paper shows how auxiliary fields can be used to express two state-dependent encapsulation disciplines: ownership, a kind of separation, and friendship, a kind of sharing. A methodology is given for specification and modular verification of encapsulated object invariants and shown sound for a class-based language. As an example the methodology is used to specify iterators, which are problematic for previous ownership systems.
VideoPlus: a method for capturing the structure and appearance of immersive environments

This paper presents a simple approach to capturing the appearance and structure of immersive scenes based on the imagery acquired with an omnidirectional video camera. The scheme proceeds by combining techniques from structure-from-motion with ideas from image-based rendering. An interactive photogrammetric modeling scheme is used to recover the locations of a set of salient features in the scene (points and lines) from image measurements in a small set of keyframe images. The estimates obtained from this process are then used as a basis for estimating the position and orientation of the camera at every frame in the video clip. By augmenting the video sequence with pose information, we provide the end-user with the ability to index the video sequence spatially as opposed to temporally. This allows the user to explore the immersive scene by interactively selecting the desired viewpoint and viewing direction.
Cause of the Observed Polarization of Electron-Induced Radiation from Helium

Recent improved measurements of threshold excitation and polarization of radiation from helium excited by electrons have led to the conclusion that previously reported "anomalies" are of experimental origin. Helium lines, $\ensuremath{\lambda}=4922,4388, \mathrm{and} 5016$ \AA{}, exhibit polarization energy dependencies similar to that previously reported for $\ensuremath{\lambda}=3889$ \AA{}. Helium lines $\ensuremath{\lambda}=4922 \mathrm{and} 4388$ \AA{} have excitation probability energy dependencies through limited energy ranges as predicted by theory. A tentative explanation of earlier results involves the contribution to both the excitation probability and the polarization of radiation caused by radially directed electrons elastically scattered from the electron beam. Attempts to reduce the radial travel of electrons have resulted in threshold and near-threshold polarization measurements which approach expected magnitudes.
More on the asymmetric infinite square well: energy eigenstates with zero curvature

We extend the standard treatment of the asymmetric infinite square well to include solutions that have zero curvature over part of the well. This type of solution, both within the specific context of the asymmetric infinite square well and within the broader context of bound states of arbitrary piecewise-constant potential energy functions, is not often discussed as part of quantum mechanics texts at any level. We begin by outlining the general mathematical condition in one-dimensional time-independent quantum mechanics for a bound-state wavefunction to have zero curvature over an extended region of space and still be a valid wavefunction. We then briefly review the standard asymmetric infinite square well solutions, focusing on zero-curvature solutions as represented by energy eigenstates in position and momentum space.
Ion Thruster Performance Impacts due to Cathode Wear

*† ‡ It has been observed in many ion thruster wear tests that the discharge loss increases with the time and the thruster performance correspondingly degrades. This behavior is usually attributed to an enlargement of the accel grid apertures during the tests due to misalignment direct-impingement and charge-exchange ion erosion, which increases the accel-grid optical transparency and thereby reduces the neutral gas pressure inside the thruster. The discharge loss change is then explained as a reduction in the ionization efficiency due to the lower neutral gas density inside the plasma generator. An analysis of the life test data using a discharge-plasma model shows that this mechanism is insufficient to explain the observed results, and even including other changes observed in the thruster parameters during the life tests such as screen grid transparency and discharge voltage only accounts for about half the measured discharge loss increase. Tests at JPL in an ion thruster simulator used in a 16,000 hour discharge cathode wear test show similar increases in discharge loss with time in spite of the fact that there is no ion accelerator or grid apertures eroding and the average pressure in the discharge chamber is essentially constant. In these tests, an increase in the cost of producing ions of nearly 10% was observed in the first 5600 hours of operation corresponding to the time period that significant keeper electrode erosion was observed. Experiments show that increases in keeper orifice diameter cause increases in discharge loss, but only at high discharge currents corresponding to the highest power levels of the thruster. This cathode-electrode erosion mechanism is likely responsible for roughly half of the total discharge loss increases observed in ion thruster life tests.
Inhibition of Pneumocystis carinii, Toxoplasma gondii, and Mycobacterium avium Dihydrofolate Reductases by 2,4-Diamino-5-[2-methoxy-5-(ω-carboxyalkyloxy)benzyl]pyrimidines: Marked Improvement in Potency Relative to Trimethoprim and Species Selectivity Relative to Piritrexim

A series of previously undescribed 2,4-diamino-5-[2-methoxy-5-alkoxybenzyl]pyrimidines (3a-e) and 2,4-diamino-5-[2-methoxy-5-(omega-carboxyalkyloxy)benzyl]pyrimidines (3f-k) with up to eight CH2 groups in the alkoxy or omega-carboxyalkyloxy side chain were synthesized and tested for the ability to inhibit partially purified dihydrofolate reductase (DHFR) from Pneumocystis carinii (Pc), Toxoplasma gondii (Tg), Mycobacterium avium (Ma), and rat liver in comparison with two standard inhibitors, trimethoprim (1) and piritrexim (2). The latter drug is known to be extremely potent but shows a marked preference for binding to mammalian DHFR, whereas the former is very selective for the parasite enzymes but is a much weaker inhibitor. The underlying strategy for the synthesis of compounds 3a-k was that a hybrid structure embodying some features of both 1 and 2 might possess a more favorable combination of potency and selectivity than either parent drug. The choice of analogues 3f-k was based on the idea that the acidic omega-carboxyl group might interact preferentially with a basic center in the active site of DHFR from any of the parasite species relative to the active site of mammalian DHFR. In addition, the omega-carboxyl group was expected to improve water solubility relative to 1 or 2. In standardized spectrophotometric assays with dihydrofolate as the substrate and NADPH as the cofactor, 2,4-diamino-5-[(2-methoxy-4-carboxybutyloxy)benzyl]pyrimidine (3g) inhibited Pc DHFR with an IC(50) of 0.049 microM and rat DHFR with IC(50) of 3.9 microM. Its potency against Pc DHFR was 140-fold greater than that of 1 and close to that of 2, and its selectivity index, defined as the ratio IC(50)(rat liver)/IC(50)(P. carinii), was 8-fold higher than that of 1 and >10(4)-fold higher than that of 2. Although it was less potent and less selective against Tg than Pc DHFR, it was very potent as well as highly selective against Ma DHFR, with an IC(50) of 0.0058 microM and an IC(50)(rat liver)/IC(50)(M. avium) ratio of >600. Because of this favorable combination of potency and selectivity relative to 1 and 2, compound 3g may be viewed as a promising lead in the search for new antifolates with potential clinical activity against P. carinii and other opportunistic pathogens in patients with AIDS.
Nonlinear Stability of Periodic Traveling-Wave Solutions of Viscous Conservation Laws in Dimensions One and Two ∗

Extending results of Oh and Zumbrun in dimensions d ≥ 3, we establish nonlinear stability and asymptotic behavior of spatially periodic traveling-wave solutions of viscous systems of conservation laws in critical dimensions d =1 , 2, under a natural set of spectral stability assumptions introduced by Schneider in the setting of reaction diffusion equations. The key new steps in the analysis beyond that in dimensions d ≥ 3 are a refined Green function estimate separating off translation as the slowest decaying linear mode and a novel scheme for detecting cancellation at the level of the nonlinear iteration in the Duhamel representation of a modulated periodic wave.
Novel approaches in the SR beamline design

Abstract High brightness third generation x-ray sources bring new experimental possibilities and impose new challenges. Coherent scattering and diffraction-limited microscopy require wave-preserving optics, high-resolution inelastic scattering novel optical elements, where x-ray interferometry or the requirements of precise polarization measurements change the optical layout. With NSLS-II development as an illustration we discuss recent trends in beamline design.
Electromagnetic properties of sea ice

Abstract Investigations of the in situ complex dielectric constant of sea ice were made using time-domain spectroscopy. It was found that (1) for sea ice with a preferred horizontal crystal c -axis alignment, the anisotropy or polarizing properties of the ice increased with depth, (2) brine inclusion conductivity increased with decreasing temperature down to about −8°C, at which point the conductivity decreased with decreasing temperature, (3) the DC conductivity of sea ice increased with increasing brine volume, (4) the real part of the complex dielectric constant is strongly dependent upon brine volume but less dependent upon the brine inclusion orientation, (5) the imaginary part of the complex dielectric constant was strongly dependent upon brine inclusion orientation but much less dependent upon brine volume. Because the electromagnetic (EM) properties of sea ice are dependent upon the physical state of the ice, which is continually changing, it appears that only trends in the relationships between the EM properties of natural sea ice and its brine volume and brine inclusion microstructure can be established.
Exact results on the temperature dependence of the specific equilibrium recombination rate coefficient

Two theorems based on Laplace transforms are used to relate threshold and high energy behavior to a temperature dependent variable. A recombination reaction involving electrically neutral species is presented to illustrate the dynamics of the activation energy and the associated rate coefficient. The distribution functions are shown to correspond with those predicted by Boltzmann's equations.
Aspartic protease inhibitors: expedient synthesis of 2-substituted statines.

General stereocontrolled synthesis of all four (2,3)-stereoisomers of 2-substituted statines is described. The 2,3-syn and 2,3-anti isomers were synthesized via β-ketoester reduction and aldol reactions, respectively. Peptides containing 2-substituted statines inhibit porcine pepsin with nanomolar IC50 values.
Boundary conditions for granular flows at randomly fluctuating bumpy boundaries

Abstract In this paper, we focus attention on the interactions between rapid flows of identical, smooth spheres that interact with bumpy boundaries through inelastic collisions. The boundaries translate with specified mean velocities, and deviate about the mean with specified fluctuation velocities. Based upon Maxwellian velocity distribution functions that describe the velocities of both the flow particles and boundaries, we calculate the rates at which linear momentum and kinetic energy are exchanged between the two. Using these exchange rates, we write down conditions that ensure that both momentum and energy are balanced at bumpy boundaries. Finally, we employ a constitutive theory that is consistent with these conditions to calculate the granular temperature and solid fraction profiles within a granular material confined between two parallel, bumpy surfaces that randomly fluctuate about zero mean velocity.
Locally constrained tyrosine analogues with restricted side chain dynamics

Abstract While investigating synthetic locally constrained analogues of amino acids, we have found that a series of tyrosine analogues, such as the 2′,6′-dimethyl-β-methyl-tyrosines, exhibit restricted rotations about their CβCγ bonds which can be detected in the 1H-NMR spectra of these compounds. The dynamic properties of these tyrosine analogues and their synthetic intermediates are described in this paper. The potential use of these tyrosine analogues in the study of the roles of side chain dynamics played in peptide-receptor interactions and protein functions also is discussed.
The one-dimensional Wigner crystal in carbon nanotubes

The one-dimensional case of the so-called ‘Wigner crystal’ phase of electrons—long predicted but previously only seen in two-dimensional electron systems—has finally been observed, in a carbon nanotube.
Elastic as Limit of Viscoelastic Response, in a Context of Self-Similar Viscous Limits

Abstract We study the equations of one-dimensional isothermal elastic response as the small viscosity limit of the equations of viscoelasticity, in a context of self-similar viscous limits for Riemann data. No size restrictions on the data or genuine-nonlinearity assumptions are imposed. The limiting procedure is justified and a solution of the Riemann problem for the equations of elasticity is obtained. The emerging solution is composed of two wave fans, each consisting of rarefactions, shocks and contact discontinuities, separated by constant states. At shocks the self-similar viscous solution has the internal structure of traveling waves, and an admissibility criterion identified by Wendroff [W] is fullfilled.