cssi/SciSciGPT-SciSciNet huggingface dataset:
Synthesis of chiral succinates via Pd(0) catalyzed carbonylation/asymmetric hydrogenation sequence

Abstract We report a novel 4 step synthesis of chiral trisubstituted succinic acid derivatives utilizing carbonylation of a vinyl triflate followed by catalytic asymmetric hydrogenation to yield the title compounds.
Rapid development of morphological descriptions for full language processing systems

I describe a compiler and development environment for feature-augmented two-level morphology rules integrated into a full NLP system. The compiler is optimized for a class of languages including many or most European ones, and for rapid development and debugging of descriptions of new languages. The key design decision is to compose morphophonological and morphosyntactic information, but not the lexicon, when compiling the description. This results in typical compilation times of about a minute, and has allowed a reasonably full, feature-based description of French inflectional morphology to be developed in about a month by a linguist new to the system.
Incorporation of tetrahedral Co(II) into a mixed-metal uranyl phosphate framework: Synthesis and structure of K2[UO2Co(PO4)2]·H2O

Abstract The hydrothermal reaction of UO2 with K3[Co(CN)6] and phosphoric acid results in the formation of K2[UO2Co(PO4)2]·H2O (KUCoP-1) as blue crystals. The crystal structure of KUCoP-1 was elucidated to reveal a three-dimensional framework constructed from UO7 pentagonal bipyramids that edge-share to form dimers that are bridged by phosphate anions into one-dimensional chains that extend down [101]. The phosphate anions also bond to Co2+ creating a tetrahedral environment as well as forming chains that extend along the c axis. The joining of these chains by the phosphate anions yields a three-dimensional framework with channels along the c axis that are occupied by K+ cations and water molecules.
Astroparticle Physics with High Energy Neutrinos: from AMANDA to IceCube

Kilometer-scale neutrino detectors such as IceCube are discovery instruments covering nuclear and particle physics, cosmology and astronomy. Examples of their multidisciplinary missions include the search for the particle nature of dark matter and for additional small dimensions of space. In the end, their conceptual design is very much anchored to the observational fact that Nature produces protons and photons with energies in excess of 1020 eV and 1013 eV, respectively. The puzzle of where and how Nature accelerates the highest energy cosmic particles is unresolved almost a century after their discovery. The cosmic ray connection sets the scale of cosmic neutrino fluxes. In this context, we discuss the first results of the completed AMANDA detector and the science reach of its extension, IceCube. Similar experiments are under construction in the Mediterranean. Neutrino astronomy is also expanding in new directions with efforts to detect air showers, acoustic and radio signals initiated by super-EeV neutrinos. The outline of this review is as follows: Introduction Why kilometer-scale detectors? Cosmic neutrinos associated with the highest energy cosmic rays High energy neutrino telescopes: methodologies of neutrino detection High energy neutrino telescopes: status
Absence of super-exponentially decaying eigenfunctions on Riemannian manifolds with pinched negative curvature

Let (X,g) be a metrically complete, simply connected Riemannian manifold with bounded geometry and pinched negative curvature, i.e. there are constants a>b>0 such that -a^2<K<-b^2 for all sectional curvatures K. Here bounded geometry is used in the sense that all covariant derivatives of the Riemannian curvature tensor are bounded and the injectivity radius is uniformly bounded below by a positive constant. We show that there are no superexponentially decaying eigenfunctions of the Laplacian of g. We also show the analogous conclusion for other geometric operators, and prove a theorem with the assumptions and conclusions localized near infinity.
Balancing broadcast reliability and transmission range in VANETs

In this paper, a novel transmit power control protocol for vehicular ad-hoc networks (VANETs) is proposed that aims to improve the reliability of safety-critical broadcasts while also maximizing the transmission range. Large transmission ranges are often desirable in order to ensure that safety-critical messages reach as many vehicles as possible, particularly in highvelocity situations. However, larger transmit powers also lead to increased channel contention and packet collisions. Further, vehicles in close proximity of the sender are likely to benefit the most from successfully receiving safety-critical information, requiring protocols that maximize the reliability of broadcasts over short distances. As a consequence, this work proposes an adaptive transmit power control approach that balances these two conflicting goals, i.e., maximizing the number of packets that are successfully received by nearby vehicles, while keeping the transmit power as large as possible to reach vehicles at larger distances. This proposed protocol incurs minimum additional overhead (since it is primarily based on simple overhearing) and works well in both highway and urban traffic scenarios.
Detection and Photometry of Hot Horizontal Branch Stars in the Core of M32

We present the deepest near-UV image of M32 to date, which for the first time resolves hot horizontal branch (HB) stars in an elliptical galaxy. Given the near-solar metallicity of M32, much larger than that of globular clusters, the existence of an extended horizontal branch is a striking example of the second parameter effect, and, most importantly, provides direct evidence that hot HB stars and their progeny are the major contributors to the UV upturn phenomenon observed in elliptical galaxies. Our image, obtained with the Space Telescope Imaging Spectrograph (STIS), detects approximately 8000 stars in a 25'' × 25'' field, centered 77 from the galaxy nucleus. These stars span a range of 21-28 mag in the STMAG system, and in the deepest parts of the image, our catalog is reasonably complete (>25%) to a magnitude of 27. The hot HB spans a magnitude range of 25-27 mag at effective temperatures hotter than 8500 K. We interpret this near-UV luminosity function with an extensive set of HB and post-HB evolutionary tracks. Although the UV-to-optical flux ratio in M32 is weak enough to be explained solely by the presence of post-asymptotic giant branch (post-AGB) stars, our image conclusively demonstrates that it arises from a small fraction (5%) of the population passing through the hot HB phase. The production of these hot HB stars does not appear to rely upon dynamical mechanisms—mechanisms that may play a role in the HB morphology of globular clusters. The majority of the population presumably evolves through the red HB and subsequent post-AGB phases; however, we see far fewer UV-bright stars than expected from the lifetimes of canonical hydrogen-burning low-mass post-AGB tracks. There are several possible explanations: (1) the transition from AGB to Teff > 60,000 K could be much more rapid than previously thought; (2) the vast majority of the post-AGB stars could be evolving along helium-burning tracks; (3) the post-AGB stars could be surrounded by circumstellar dust during the transition from the AGB to Teff > 60,000 K.
Leaders, laggards, and the pursuit of foreign knowledge

This paper analyzes how firms in different technological and market share positions use foreign R&D to augment their technological capabilities. Technology transfer issues and absorptive capacity arguments are examined to analyze the different technological capabilities of leading and lagging firms. In addition, a new strategic rationale (in terms of non-dominant market share firms) that has not been considered in prior studies analyzing knowledge-seeking FDI is offered. From a panel dataset which includes information on all foreign R&D investments made by publicly traded Japanese manufacturing firms (from 1974 to 1994), I show that Japanese firms investing in foreign R&D tend to be the non-dominant market share firms, but also the technologically leading firms across fairly diverse industries. By considering both the technological and market share positions of firms, this study reveals important characteristics that influence when firms use foreign R&D as part of a strategy to augment their technological capabilities. Copyright © 2005 John Wiley & Sons, Ltd.
The crisis in Somalia: Tragedy in five acts

ABSTRACTSomalia's catastrophic humanitarian crisis of 2007, in which up to 300,000 Mogadishu residents were displaced in fighting pitting Ethiopian and Transitional Federal Government (TFG) forces against a complex insurgency of clan and Islamist opposition, was the culmination of a series of political miscalculations and misjudgements on the part of Somali and external actors since 2004. They resulted in a cascading sequence of political crises which plunged Somalia into increasingly intractable conflicts. This ‘tragedy in five acts’ includes the flawed creation of the TFG in late 2004, which emerged as a narrow coalition rather than a government of national unity; the failure of a promising civic movement in Mogadishu in summer of 2005 to challenge the power base of warlords and Islamists in the capital; the disastrous decision by the US government to encourage an alliance between its local counter-terrorism partners in Mogadishu, producing a war which led to the victory of the Council of Islamic Courts (CIC) in June 2006; the radicalization of the CIC over the course of 2006, which guaranteed a war with Ethiopia; and the Ethiopian offensive against the CIC in late 2006, leading to its occupation of the capital, a complex insurgency against Ethiopian forces and armed violence which produced what the UN described as a ‘humanitarian catastrophe’. In virtually every instance, key actors took decisions that produced unintended outcomes which harmed rather than advanced their interests, and at a cost in human lives and destruction of property that continues to mount.
How to give away software with successive versions

Free software offer as a promotional tool has been employed by software firms of all sizes. In this research, we propose an extended multi-generation diffusion model that separates substitution from switching, and develop methodologies to help a firm determine the optimal number of free adoptions for each version. Our analyses show that due to the word-of-mouth effect, free offer can help increase a firm's total profit for all versions of a product. Furthermore, we find that in the presence of low-valuation free adopters, the optimal number of high-valuation free adopters decreases, the total number of free adopters increases, and the total profit improves substantially as a result.
One-pot sequential cross-metathesis/hydride reduction: highly stereoselective synthesis of primary (E)-allylic alcohols from terminal olefins

Several di- and trisubstituted primary (E)-allylic alcohols have been prepared from the corresponding terminal olefins in a highly stereoselective manner (>20:1 E/Z) by sequencing olefin cross-metathesis (CM) with hydride reduction (DIBAL-H) in good yields utilizing only commercially available reagents in a one-pot fashion. The method is a reliable alternative to the direct CM of terminal olefins with allyl alcohol, which is not always stereoselective but rather highly substrate dependent.
Closed Form Magnetic Quarter Orbit Switch Point Solution.

Abstract : A closed form solution is derived for determining the location of a set of magnetic switch points, spaced 90 deg apart in the orbit, which will allow the spin axis of a satellite to be moved in any, achievable, desired direction from any initial orientation. Additional closed form equations are derived for determining the magnitude of the motion that will result for a given set of switch points. The simplicity of the calculations make the technique extremely useful for applications where savings in computer time or storage are desired and for design studies where quick solutions to many cases are required. (Author)
The Type Ia Supernova Rate

We explore the idea that the Type Ia supernova (SN Ia) rate consists of two components: a prompt piece that is proportional to the star formation rate (SFR), and an extended piece that is proportional to the total stellar mass. We fit the parameters of this model to the local observations by Mannucci and collaborators and then study its impact on three important problems. On cosmic scales, the model reproduces the observed SN Ia rate density below z = 1 and predicts that it will track the measured SFR density at higher redshift, reaching a value of (1-3.5) × 10-4 yr-1 Mpc-3 at z = 2. In galaxy clusters, a large prompt contribution helps explain the Fe content of the intracluster medium. Within the Galaxy, the model reproduces the observed stellar [O/Fe] abundance ratios if we allow a short (≈0.7 Gyr) delay in the prompt component. Ongoing medium-z SN surveys will yield more accurate parameters for our model.
A Lower Bound on the Cosmic Baryon Density

We derive lower bounds on the cosmic baryon density from the requirement that the high-redshift intergalactic medium (IGM) contain enough neutral hydrogen to produce the observed Lyα absorption in quasar spectra. These analytic bounds follow from a key theoretical assumption—that absorbing structures are on average no more extended in redshift space than in real space—which is likely to hold in the gravitational instability picture of the Lyα forest, independently of the details of the cosmological model. The other ingredients that enter these bounds are an estimate of (or lower limit to) the intensity of the photoionizing UV background from quasars, a temperature T ~ 104 K for the "warm" photoionized IGM that produces most of the Lyα absorption, a value of the Hubble constant, and observational estimates of the mean Lyα flux decrement or, for a more restrictive bound, the distribution function P(τ) of Lyα optical depths. With plausible estimates of the quasar UV background and , the mean decrement bound implies a baryon density parameter Ωb 0.0125 h-2, where h ≡ H0/(100 km s-1 Mpc-1). A recent observational determination of P(τ) implies that Ωb 0.0125 h-2 even for a conservative estimate of the quasar UV background, and Ωb 0.018 h-2 for a more reasonable estimate. These bounds are consistent with recent low estimates of the primordial deuterium-to-hydrogen ratio (D/H)P, which imply that Ωb ≈ 0.025 h-2 when combined with standard big bang nucleosynthesis. Since the bounds account only for baryons in the warm IGM, their combination with the nucleosynthesis constraint implies that most of the baryons in the universe at z ~ 2-4 were distributed in diffuse intergalactic gas rather than in stars or compact dark objects. The P(τ) bound on Ωb is incompatible with some recent high estimates of (D/H)P, unless one drops the assumptions of standard big bang nucleosynthesis or abandons the idea that Lyα forest lines originate in the smooth, large-scale structures of photoionized gas that arise in gravitational instability theories.
Some psychologic factors in prolonged labor due to inefficient uterine action.

Summary The role of psychological factors as causative or contributory to the development of ineffective uterine activity during labor is reviewed. Eighteen primiparas with inefficient uterine action, i.e., no progress in dilatation or effacement of the cervix in the absence of cephalopelvic disproportion, were compared to 43 primiparas with normal labor from the same Obstetrical and psychological findings in the two groups were compared. The mean duration of labor was 23.9 hours in the abnormal group and 10.8 hours in the control group. Significant statistical differences were found between the mean scores of the two groups in the following items: attitude to motherhood; attitude to sex and marriage; relationship to mother; adjustment to pregnancy; concept of early home life; predelivery concept of labor; habitual neurotic bodily complaints; habitual anxieties, worries and fears; attitude to first menses; and attitude to father of child. The difference between the mean total scores of these ten items was highly significant in distinguishing the women who had had ineffective uterine activity during labor from the control group.
Momentum exchange - Feedback control of flexible spacecraft maneuvers and vibration

The momentum exchange controller in which the time rate of change of the flexible momentum relative to the rigid-body motion is used as a part of the feedback control law for maneuvers and vibration suppression of flexible systems is introduced. This control concept is applied to a model of a rigid hub (base) with a cantilevered flexible appendage undergoing a single-axis maneuver. The feedback control on the hub includes the rigid-body motion and the time rate of change of that part of the flexible momentum resulting from flexible vibration. The lower and upper bounds of the control law for system Lyapunov stability are obtained, and the relationship of the control law with the energy Lyapunov test function is established. With the presence of this feedback control, an additional independent flexible control system acting on the flexible parts can be designed for further vibration suppression. This hybrid control system can be applied to both stationkeeping and large-angle maneuvers. Both analytical and numerical results are presented to show the theoretical and practical merit of this approach.
Growth of Betti numbers

Abstract We discuss growth rates of Betti numbers in a family of coverings of a compact cell complex X , when the corresponding L 2 Betti number of X is zero. We show that the Betti numbers are bounded by a function, sub-linear in the order of the covering. If the appropriate Novikov–Shubin invariant of X is positive, the rate bounds are improved. For well behaved families (such as congruence covers of symmetric spaces), if the L 2 spectrum of X has a gap at zero then the growth rate is bounded by the order of the covering raised to a power less than one.
Inside-out core–shell architecture: controllable fabrication of Cu2O@Cu with high activity for the Sonogashira coupling reaction

Inside-out core–shell architectures (Cu2O@Cu) with a Cu2O core and a Cu shell, which are in contrast to the normally reported Cu2O-outside structure (Cu@Cu2O), were fabricated. This strategy can also be applied to construct square and hexapod Cu2O@Cu. The obtained Cu2O@Cu composite exhibits excellent catalytic activity for the Sonogashira coupling reactions.
The Effects of Intrauterine Malnutrition on Birth and Fertility Outcomes: Evidence From the 1974 Bangladesh Famine

This article uses the Bangladesh famine of 1974 as a natural experiment to estimate the impact of intrauterine malnutrition on sex of the child and infant mortality. In addition, we estimate the impact of malnutrition on post-famine pregnancy outcomes. Using the 1996 Matlab Health and Socioeconomic Survey (MHSS), we find that women who were pregnant during the famine were less likely to have male children. Moreover, children who were in utero during the most severe period of the Bangladesh famine were 32 % more likely to die within one month of birth compared with their siblings who were not in utero during the famine. Finally, we estimate the impacts of the famine on subsequent pregnancy outcomes. Controlling for pre-famine fertility, we find that women who were pregnant during the famine experienced a higher number of stillbirths in the post-famine years. This increase appears to be driven by an excess number of male stillbirths.
Repeated Bargaining with Persistent Private Information

The paper analyses repeated contract negotiations involving the same buyer and seller where the contracts are linked because the buyer has persistent (but not fully permanent) private information. The size of the surplus being divided is specified as a two-state Markov chain with transitions that are synchronized with contract negotiation dates. Equilibrium involves information cycles triggered by the success or failure of aggressive demands made by the seller. Because there is persistence in the Markov chain generating the surplus, a successful demand induces the seller to make another aggressive demand in the next negotiation, since the buyer's acceptance reveals that the current surplus is large. Rejection of an aggressive demand, on the other hand, leads the seller to be pessimistic about the size of the surplus in the next contract, so the seller makes a "soft" offer that is sure to be accepted. Then, after several such offers have been accepted, the seller is optimistic enough to again make an aggressive demand, creating an information cycle. An interesting feature of this cycle is that the soft price is not constant, but declines as the cycle continues, so as to offset the buyer's option value of re-starting the cycle when the current state is bad. An explicit mapping is given for the relationship between the basic parameters and the equilibrium prices and quantities; in particular, there is a closed-form solution for the threshold belief that makes the seller indifferent between hard and soft offers.
Massive star-forming host galaxies of quasars on Sloan digital sky survey stripe 82

The stellar properties of about 800 galaxies hosting optically luminous, unobscured quasars at z 1010 M ?), which is consistent with previous results for less luminous narrow-line (obscured) active galactic nuclei (AGNs). The quasar hosts are very blue and almost absent on the red sequence, showing stark contrast to the color-magnitude distribution of normal galaxies. The fact that more powerful AGNs reside in galaxies with higher star-formation efficiency may indicate that negative AGN feedback, if it exists, is not concurrent with the most luminous phase of AGNs. We also find positive correlation between the mass of supermassive black holes (SMBHs; M BH) and host stellar mass, but the M BH-M star relation is offset toward large M BH or small M star compared to the local relation. While this could indicate that SMBHs grow earlier than do their host galaxies, such an argument is not conclusive, as the effect may be dominated by observational biases.
THE CORE COMPOSITION OF A WHITE DWARF IN A CLOSE DOUBLE-DEGENERATE SYSTEM

We report the identification of the double-degenerate system NLTT?16249 that comprises a normal, hydrogen-rich (DA) white dwarf and a peculiar, carbon-polluted white dwarf (DQ) showing photospheric traces of nitrogen. We disentangled the observed spectra and constrained the properties of both stellar components. In the evolutionary scenario commonly applied to the sequence of DQ white dwarfs, both carbon and nitrogen would be dredged up from the core. The C/N abundance ratio (50) in the atmosphere of this unique DQ white dwarf suggests the presence of unprocessed material (14N) in the core or in the envelope. Helium burning in the DQ progenitor may have terminated early on the red giant branch after a mass-ejection event leaving unprocessed material in the core, although current mass estimates do not favor the presence of a low-mass helium core. Alternatively, some nitrogen in the envelope may have survived an abridged helium-core burning phase prior to climbing the asymptotic giant branch. Based on available data, we estimate a relatively short orbital period (P 13?hr) and ongoing spectroscopic observations will help determine precise orbital parameters.
User interface design issues for a large interactive system

User interface design issues are discussed for a large interactive system. The assumptions about the user environment are explicitly described. Issues discussed include command language syntax, command recognition and completion, subsystem organization, user extension capabilities, user options, and various forms of prompting, help and feedback. These issues are discussed within the context of an existing system, the NLS system.
The Relationship between the Integration of Faith and Work with Life and Job Outcomes

Gallup surveys consistently show that nine in 10 Americans express a belief in God (Nash, Business, religion, and spirituality: A new synthesis, 2003), while more than 45 % claim to have some awareness of God on the job (Nash and McLellan, Church on Sunday, Work on Monday: The Challenges of Fusing Christian Values with Business Life, 2001). Recently, Lynn et al. (Journal of Business Ethics 85:227–243, 2009) argued that the ability to integrate the specific beliefs and practices of one’s faith with the work one does represent an important although neglected area of research. As such, they developed and demonstrated convergent validity for the faith at work scale, designed to measure the extent to which individuals believe they are able to integrate their Judaeo-Christian beliefs and practices and their work. In a subsequent study, Lynn et al. (Human Relations 64:675–701, 2010) demonstrated that the faith at work scale was related to faith maturity, church attendance, age, and denominational strictness, and negatively associated with organizational size. No research, however, has examined the possible positive benefits of integrating faith and work. I therefore developed and tested hypotheses concerning the relationship between the faith at work scale and seven important life and work outcomes (satisfaction with life, intent to leave one’s job, self-rated job performance, job satisfaction, and three forms of organizational commitment). In all, four of seven hypotheses were confirmed.
RADIOGRAPHIC EVALUATION OF SURGICAL CLIPS IS BETTER THAN ULTRASOUND FOR DEFINING THE LUMPECTOMY CAVITY IN BREAST BOOST TREATMENT PLANNING: A PROSPECTIVE CLINICAL STUDY

Abstract Purpose: Breast radiotherapy (BrRT) often includes a "boost" to the lumpectomy bed. Selection of an appropriate electron energy and field size is based upon the dimensions and location of the surgical cavity. This study was performed to confirm our impression that ultrasound (US) inadequately defines the volume at risk compared to radiographic evaluation of surgical clips placed within the operative bed at the time of lumpectomy. Methods and Materials: Twenty-nine women treated with BrRT at our institution between 1996–1998 were prospectively identified as having surgical clips within the lumpectomy cavity. These patients underwent both US evaluation and radiographic evaluation of the clips to independently define two sets of transverse (T), longitudinal (L), and depth (D) measurements for each cavity. Volumes (V) were calculated for each method, assuming the cavity to be a box (V = T × L × D). Twenty-one women began BrRT following a median postoperative interval of 6 weeks (Group A), and 8 after 24 weeks (Group B) due to delivery of systemic therapy. Results: Dimensions derived by US were smaller than the clip method in 22/29 of T, 25/29 of L, and 23/29 of D, or 80% of all linear measurements. A paired t -test demonstrated the difference between the methods to be statistically significant: T: p = 0.0004; L: p = 0.0001; D: p = 0.0004; and V: p = 0.0001. This underestimation by US did not fit any predictable pattern. Although the mean difference between methods (clips − US) was only 1.3, 1.9, and 1.1 cm for T, L, and D, respectively, differences ranged up to 5.7, 9.2, and 5.5 cm for T, L, and D. The bias toward underestimation of V by US was significantly greater for Group B than Group A ( p = 0.03). Conclusions: US significantly underestimates all three dimensions of the lumpectomy cavity and hence the volume at risk compared to radiographic evaluation of surgical clips. Breast-conserving surgery should include placement of clips at the margins of the lumpectomy cavity (superior, inferior, medial, lateral, and posterior) to aid in radiotherapy treatment planning. US should not be utilized to guide the design of the boost field as it will result in inappropriate selection of lower electron energies and smaller field sizes (geographical miss), particularly among patients who receive chemotherapy prior to breast radiotherapy.
The congruence criterion for power operations in Morava $E$-theory

We prove a congruence criterion for the algebraic theory of power operations in Morava E-theory, analogous to Wilkerson's congruence criterion for torsion free lambda-rings. In addition, we provide a geometric description of this congruence criterion, in terms of sheaves on the moduli problem of deformations of formal groups and Frobenius isogenies.
Observational Features of Cosmic Gamma-Ray Bursts: Evidence for Galactic versus Extragalactic Origin

The recent observational data on gamma-ray bursts are reviewed. Burst time histories display features at the millisecond level which suggest a compact object origin. Lines in the energy spectra and spectral evolution point toward a Galactic neutron star origin, even though line features have not yet been confirmed in recent data. The Galactic distribution of burst sources, however, is both isotropic and sampled to its characteristic distance, making it unlikely that the sources are related to populations of Galactic neutrons stars we are familiar with. Counterpart searches, previously carried out years after the gamma-ray bursts, are now proceeding days after the events. Based on the current data, it is impossible to conclude whether bursters are Galactic, extragalactic, or both. Data being returned from current experiments, as well as data from new experiments to be launched in the next few years, may yet provide the answer.
Transverse motion of high-speed barium clouds in the ionosphere

Simulation results, based on a field-line-integrated, two-dimensional, electrostatic model, are presented for the motion of a barium cloud injected transverse to the geomagnetic field in the ionosphere at high speeds. It is found that the gross evaluation of injected plasma clouds depends on the initial conditions, as well as the nature of the background coupling. For a massive (mass of about 10 kg), orbital (velocity of about 5 km/s) release in the F region (350-450 km), it is found that plasma clouds can drift tens of kilometers across the magnetic field in tens of seconds after ionization. This type of release is similar to those which are planned for the Combined Release and Radiation Effects Satellite mission.
NaV3(OH)6(SO4)2: A Kagomé‐Type Vanadium(III) Compound with Strong Intralayer Ferromagnetic Interactions

A dominant ferromagnetic exchange interaction propagates about the magnetic sites of the Kagome lattice of the title compound through the bridging hydroxy groups (see section of the structure). This is at variance with the antiferromagnetic exchange observed for jarosite and its derivatives. The ferromagnetism probably arises from the d2 electron count of the VIII centers.
A higher order multilevel fast multipole algorithm for scattering from mixed conducting/dielectric bodies

A higher order multilevel fast multipole algorithm (MLFMA) is presented for computing electromagnetic scattering from three-dimensional bodies comprising both conducting and dielectric objects. The problem is formulated using the Poggio-Miller-Chang-Harrington-Wu-Tsai (1973, 1977) approach for multiple homogeneous dielectric objects and the combined-field approach for conducting objects. The resultant integral equations are discretized by the method of moments (MoM), in which the conducting and dielectric surfaces/interfaces are represented by curvilinear triangular patches and the unknown equivalent electric and magnetic currents are expanded using higher order vector basis functions. Such a discretization yields a highly accurate representation of the unknown currents without compromising the accuracy of geometrical modeling. An implicit matrix-filling scheme is employed to facilitate the treatment of complex scatterers having multiple junctions. The resultant numerical system is then solved by MLFMA, which is tailored to accommodate the material properties of dielectric scatterers, and the solution is accelerated using an incomplete LU decomposition preconditioner. Numerical examples are presented to demonstrate the accuracy and versatility of this approach in dealing with a wide array of scattering problems.
voboz: an almost-parameter-free halo-finding algorithm

We have developed an algorithm, called VOBOZ (VOronoi BOund Zones), to find haloes in an N-body dark matter simulation; it has as little dependence on free parameters as we can manage. By using the Voronoi diagram, we achieve non-parametric, ‘natural’ measurements of each particle’s density and set of neighbours. We then eliminate much of the ambiguity in merging sets of particles together by identifying every possible density peak, and measuring the probability that each does not arise from Poisson noise. The main halo in a cluster tends to have a high probability, while its subhaloes tend to have lower probabilities. The first parameter in VOBOZ controls the subtlety of particle unbinding, and may be eliminated if one is cavalier with processor time; even if one is not, the results saturate to the parameter-free answer when the parameter is sufficiently small. The only parameter that remains, an outer density cut-off, does not influence whether or not haloes are identified, nor does it have any effect on subhaloes; it only affects the masses returned for supercluster haloes. Ke yw ords: methods: data analysis ‐ methods: N-body simulations ‐ galaxies: formation ‐ galaxies: haloes ‐ cosmology: theory ‐ large-scale structure of Universe.
Acoustic Imaging in a Water Filled Metallic Pipe

A method is described for the imaging of the interior of a water filled metallic pipe using acoustical techniques. The apparatus consists of an array of 20 acoustic transducers mounted circumferentially around the pipe. Each transducer is pulsed in sequence, and the echos resulting from bubbles in the interior are digitized and processed by a computer to generate an image. The electronic control and digitizing system and the software processing of the echo signals are described. The performance of the apparatus is illustrated by the imaging of simulated bubbles consisting of thin walled glass spheres suspended in the pipe.
Evaluating the EMS and EMU using stochastic simulations : some issues

Evaluations of European monetary integration using model simulations have given conflicting results, and the paper attempts to elucidate the reasons for the differences. Several features stand out: how to model realignments; how monetary policy is set for individual countries or for Europe; and how large are risk premium shocks in exchange markets. We quantify the effects of different assumptions relating to these features using MULTIMOD.
One-pot, four-different-component annulations: flexible and efficient conversion of n-sized cycloalkenones into n+4 alkenolides

Abstract Five-, six-, and seven-membered conjugated cycloalkenones undergo one-pot conjugate addition with tri- n -butyltinlithium followed by 1,4-addition to vinyl ketones and then aldol addition to aldehydes leading to cyclic hemiketals 2 . Lead tetraacetate oxidative fragmentation produces various 4-atom enlarged, vicinally disubstituted, regiospecifically and stereospecifically unsaturated macrolides 3 .
Spontaneous curvature cancellation in forced thin sheets

In this paper we report numerically observed spontaneous vanishing of mean curvature on a developable cone made by pushing a thin elastic sheet into a circular container [E. Cerda, S. Chaieb, F. Melo, and L. Mahadevan, Nature (London) 401 46 (1999)]. We show that this feature is independent of thickness of the sheet, the supporting radius, and the amount of deflection. Several variants of the developable cone are studied to examine the necessary conditions that lead to the vanishing of mean curvature. It is found that the presence of appropriate amount of radial stress is necessary. The developable cone geometry somehow produces the right amount of radial stress to induce just enough radial curvature to cancel the conical azimuthal curvature. In addition, the circular symmetry of supporting container edge plays an important role. With an elliptical supporting edge, the radial curvature overcompensates the azimuthal curvature near the minor axis and undercompensates near the major axis. Our numerical finding is verified by a crude experiment using a reflective plastic sheet. We expect this finding to have broad importance in describing the general geometrical properties of forced crumpling of thin sheets.
Third-country effects on the formation of free trade agreements

The recent proliferation of free trade agreements (FTAs) has resulted in an increasingly complex network of preferential trading relationships. The economics literature has generally examined the formation of FTAs as a function of the participating countries' economic characteristics alone. In this paper, we show both theoretically and empirically that the decision to enter into an FTA is also crucially dependent on the participating countries' existing FTA relationships with third countries. Accounting for the interdependence of FTAs helps to explain a significant fraction of FTA formations that would not otherwise be predicted by countries' economic characteristics.
The evolution of unstable black holes in anti-de Sitter space

We examine the thermodynamic stability of large black holes in four-dimensional anti-de Sitter space, and we demonstrate numerically that black holes which lack local thermodynamic stability often also lack stability against small perturbations. This shows that no-hair theorems do not apply in anti-de Sitter space. A heuristic argument, based on thermodynamics only, suggests that if there are any violations of Cosmic Censorship in the evolution of unstable black holes in anti-de Sitter space, they are beyond the reach of a perturbative analysis.
Evaluation of the one-well uranium leaching test: restoration

The purpose of this study is to show how and to what extent the adsorption parameters can be obtained from push-pull test data and the sensitivity of the effluent history to the various factors mentioned. This is accomplished by two techniques: the coherence method, which neglects dispersion and assumes homogeneous media, and a two-dimensional finite difference solution of the appropriate concentration balance equation, which takes dispersion into account and can include heterogeneity. 8 refs.
Near-field high temperature transport: evidence from the genesis of the Osamu Utsumi uranium mine, Poços de Caldas alkaline complex, Brazil

Abstract The chemical, isotopic and mineralogical alteration which occurred during primary uranium ore deposition at the breccia pipe-hosted Osamu Utsumi mine, Pocos de Caldas, Brazil was studied as a natural analogue for near field radionuclide migration. Chemical and isotopic alteration models were combined with finite difference models of the convective cooling of caldera intrusives. The modeling indicates that the intense chemical, isotopic, and mineralogical alteration of the Osamu Utsumi breccia pipe requires the circulation of > 10 5 kg/cm 2 of boiling hydrothermal fluid > 200°C through each square centimeter cross-section of the pipe. This circulation could be driven by heat from a 6 km diameter intrusive extending to 10 km depth. Even with this large amount of circulation concentrated in the permeable breccia pipe, uranium solubilities must be 2 1 2 orders of magnitude greater than indicated in the most recent experiments (and more in line with previous estimates) to produce the primary uranium mineralization at the Osamu Utsumi mine. The same models applied to a hypothetical high temperature waste repository show that heat from radioactive decay will produce a hydrothermal circulation system remarkably similar to that studied at the natural analogue site at Pocos de Caldas. The depth of fluid convection induced by the hypothetical repository would be 5 to 10 km, the maximum temperature would be ∼ 300°C, the lifetime of the high temperature phase would be a few thousand years, and boiling would occur and cause most of the alteration within the hypothetical waste repository. This physical analysis emphasizes the importance of permeability on a 10 × 10 × 10 km scale in controlling the potential amount of circulation through the hypothetical repository. Application of the chemical models successfully used to interpret mineralization and alteration at the Pocos de Caldas Osamu Utsumi mine to the hypothetical waste repository shows that even in a worst case scenario (waste implaced in a permeable host rock with no measures taken to inhibit flow though the repository) the amount of hydrothermal alteration in the hypothetical repository will be ∼ 0.1% of that in the breccia pipe at Osamu Utsumi. Assuming no barriers to uranium mobility, uranium precipitation above the hypothetical repository would be 0.04 ppm (rather than 40 ppm), hydrothermal alteration 0.03 wt% (rather than 30 wt%), etc. Our analysis indicates that modeled mineralogical alteration is sensitive to the thermodynamic data base used. Prediction of mineralogical alteration (which may be necessary to predict the migration of radionuclides other than uranium, for example) probably cannot be based directly on even very carefully collected laboratory thermodynamic data. Mineralogical complexities of the system, as well as data base uncertainties will require calibration of the thermodynamic framework against mineralogical alteration observed in the laboratory or field.
Ru-Catalyzed Asymmetric Hydrogenation of α-Phthalimide Ketones and 1,3-Diaryl Diketones Using 4,4‘-Substituted BINAPs

A family of tunable precatalysts [NH2Et2][{Ru(4,4‘-BINAP)Cl}2(μ-Cl)3] was synthesized and used for highly enantioselective hydrogenation of phthalimide-protected amino ketones and 1,3-diaryldiketones. The bulky groups on the 4,4‘-positions of BINAP were believed to be responsible for the enhancement of enantioselectivity (and diasteroselectivity) in these reactions.
A framework for evaluating national space activity

Abstract Space technology and resources are used around the world to address societal challenges. Space provides valuable satellite services, unique scientific discoveries, surprising technology applications and new economic opportunities. Many developing countries formally recognize the advantages of space resources and pursue national level activity to harness them. There is limited data or documentation on the space activities of developing countries. Meanwhile, traditional approaches to summarize national space activity do not necessarily capture the types of activity that developing countries pursue in space. This is especially true if they do not have a formal national space program or office. Developing countries pursue national space activity through activities of many types—from national satellite programs to commercial use of satellite services to involvement with international space institutions. This research aims to understand and analyze these trends. This paper introduces two analytical frameworks for evaluating space activity at the national level. The frameworks are specifically designed to capture the activity of countries that have traditionally been less involved in space. They take a broad view of space related activity across multiple societal sectors and disciplines. The discussion explains the approach for using the frameworks as well as illustrative examples of how they can be applied as part of a research process. The first framework is called the Mission and Management Ladders. This framework considers specific space projects within countries and ranks them on “Ladders” that measure technical challenge and managerial autonomy. This first method is at a micro level of analysis. The second framework is called the Space Participation Metric (SPM). The SPM can be used to assign a Space Participation score to countries based on their involvement in various space related activities. This second method uses a macro level of analysis. The authors developed both frameworks as part of a long term research program about the space activities of developing countries. This aspect of the research focuses on harnessing multiple techniques to summarize complex, multi-disciplinary information about global space activity.
Convergence of periodically forced rank-type equations

Consider a difference equation which takes the k-th largest output of m functions of the previous m terms of the sequence. If the functions are also allowed to change periodically as the difference equation evolves, this is analogous to a differential equation with periodic forcing. A large class of such non-autonomous difference equations are shown to converge to a periodic limit, which is independent of the initial condition. The period of the limit does not depend on how far back each term is allowed to look back in the sequence, and is in fact equal to the period of the forcing.
A necessary and sufficient condition for Ricci shrinkers to have positive AVR

In this short note we observe that a recent result of C.-W. Chen meshes well with earlier work of H.-D. Cao and D.-T. Zhou, O. Munteanu, J. Carrillo and L. Ni, and S.-J. Zhang to give a necessary and sufficient condition for complete noncompact shrinking gradient Ricci solitons to have positive asymptotic volume ratio.
The determinacy of infinite games with eventual perfect monitoring

An infinite two-player zero-sum game with a Borel winning set, in which the opponent’s actions are monitored eventually but not necessarily immediately after they are played, admits a value. The proof relies on a representation of the game as a stochastic game with perfect information, in which Nature operates as a delegate for the players and performs the randomizations for them.
Several Complex Variables and the Distribution of Resonances in Potential Scattering

We study resonances associated to Schrodinger operators with compactly supported potentials on ℝd, d≥3, odd. We consider potentials depending holomorphically on a parameter Open image in new window For certain such families, for all z except those in a pluripolar set, the associated resonance–counting function has order of growth d.
Resolved Motion Adaptive Control for Mechanical Manipulators

This paper presents the development of a resolved motion adaptive control which adopts the ideas of "resolved motion rate control" [4] and "resolved motion acceleration control" [6] to control a manipulator in Cartesian coordinates for various loading conditions. The proposed adaptive control is performed at the hand level and is based on the linearized perturbation system along a desired hand trajectory. The controlled system is characterized by feedforward and feedback components which can be computed separately and simultaneously. The feedforward component resolves the specified positions, velocities, and accelerations of the hand into a set of values of joint positions, velocities, and accelerations from which the nominal joint torques are computed using the Newton-Euler equations of motion to compensate all the interaction forces among the various joints. The feedback component consisting of recursive least square identification scheme and an optimal adaptive self-tuning controller for the linearized system computes the perturbation torques which reduce the manipulator hand position and velocity errors along the nominal hand trajectory. The feasibility of implementing the proposed adaptive control using present day low-cost microprocessors is explored.