Communication: Partial polarization transfer for single-scan spectroscopy and imaging

A method is presented to partially transfer nuclear spin polarization from one isotope S to another isotope I by the way of heteronuclear spin couplings, while minimizing the loss of spin order to other degrees of freedom. The desired I spin polarization to be detected is a design parameter, while the sequence of pulses at the two Larmor frequencies is optimized to store the greatest unused S spin longitudinal polarization for subsequent use. The unitary evolution for the case of I_NS spin systems illustrates the potentially ideal efficiency of this strategy, which is of particular interest when the spin-lattice relaxation time of S greatly exceeds that of I. Explicit timing and pulses are tabulated for the cases for which M ≤ 10 partial transfers each result in equal final polarization of 1/M or more compared to the final I polarization expected in a single transfer for N = 1, 2, or 3 I spins. Advantages for the ratiometric study of reacting molecules and hyperpolarized initial conditions are outlined

Declining Volatility in the U.S. Automobile Industry

This paper documents the dramatic changes in volatility that occurred in the U.S. auto industry in the early 1980s. Namely, output volatility declined significantly, the covariance of inventory investment and sales became much more negative, and adjustments to output, which in earlier decades stemmed primarily from plants hiring and laying off workers, were more often accomplished with changes in average hours per worker after the mid 1980s. Building on the work of Blanchard (1983), we show how all of these changes could have stemmed from one underlying factor%u2014a decline in the persistence of motor vehicle sales. We use both industry-level data as well as micro data on production schedules from 103 assembly plants in the United States and Canada to document the developments in the early 1980s. We then use the original Holt, Modigliani, Muth and Simon (1960) linear quadratic inventory model to show how a decline in the persistence of sales leads to all of the changes noted above, including the propensity to use intensive margins of adjustment over extensive labor margins, even in the absence of technological change.

Tracking the Source of the Decline in GDP Volatility: An Analysis of the Automobile Industry

Recent papers by Kim and Nelson (1999) and McConnell and Perez-Quiros (2000) uncover a dramatic decline in the volatility of U.S. GDP growth beginning in 1984. Determining whether the source is good luck, good policy or better inventory management has since developed into an active area of research. This paper seeks to shed light on the source of the decline in volatility by studying the behavior of the U.S. automobile industry, where the changes in volatility have mirrored those of the aggregate data. We find that changes in the relative volatility of sales and output, which have been interpreted by some as evidence of improved inventory management, are in fact the result of changes in the process driving automobile sales. We first show that the autocorrelation of sales dropped during the 1980s, and that the behavior of interest rates may be the force behind the change in sales persistence. A simulation of the assembly plants' cost function illustrates that the persistence of sales is a key determinant of output volatility. A comparison of the ways in which assembly plants scheduled production in the 1990s relative to the 1970s supports the intuition of the simulation.

Why Do Real and Nominal Inventory-Sales Ratios Have Different Trends

This note explains the diverging trends between real and nominal aggregate inventory-sales ratios. The combined effect of two features of the data explains the divergence. First, while aggregate sales include both goods and services, inventories include only goods. Second, there has been a strong secular decrease in the relative price of goods. The combination of these two factors causes the real and nominal aggregate inventory-sales ratios to have different trends.

Nanoscale Torsional Resonator for Polarization and Spectroscopy of Nuclear Spins

We propose a torsional resonator that couples to the transverse spin dipole of an attached sample. The absence of relative motion eliminates a source of friction that would otherwise hinder nanoscale implementation. Enhanced spontaneous emission induced by the resonator relaxes the longitudinal spin dipole at a rate of ~1  s^(-1) in the low-temperature limit. With signal averaging, single-proton magnetic resonance spectroscopy appears feasible at ~10  mK and a high magnetic field, while single-shot sensitivity is practical for samples with at least tens of protons in a volume of ~5  nm^3

Hyperpolarized ^1H NMR employing low γ nucleus for spin polarization storage

The PASADENA (parahydrogen and synthesis allow dramatically enhanced nuclear alignment)(1, 2) and DNP (Dynamic Nuclear Polarization)(3) methods efficiently hyperpolarize biologically relevant nuclei such as 1^H, (31)^P, (13)^C, (15)^N achieving signal enhancement by a factor of ~ 100000 on currently utilized MRI scanners. Recently, many groups have demonstrated the utility of hyperpolarized MR in biological systems using hyperpolarized (13)^C biomarkers with a relatively long spin lattice relaxation time T_1 on the order of tens of seconds.(4-7) Moreover, hyperpolarized (15)^N for biomedical MR has been proposed due to even longer spin lattice relaxations times.(8) An additional increase of up to tens of minutes in the lifetime of hyperpolarized agent in vivo could be achieved by using the singlet states of low gamma (γ) nuclei.(9) However, as NMR receptivity scales as γ^3 for spin 1/2 nuclei, direct NMR detection of low γ nuclei results in a lower signal-to-noise ratio compared to proton detection. While protons are better nuclei for detection, short spin lattice relaxation times prevent direct 1^H hyperpolarized MR in biomedical applications

Towards the Knowledge in Coalgebraic Model of IDS

In the last decades linear logic became a useful logical system for various usage in computer science. Its ability to handle resources and its competence to describe dynamics of processes predetermine it for describing behaviour of programs and program systems. Linear logic can be apprehended as a multiplicative and additive extension of usual logic. We show the possibilities how these fragments can be enriched to describe behaviour and to achieve knowledge on an example of simplified Intrusion Detection System (IDS). We construct Kripke model over a coalgebra of modal linear logic for pursuing observable behaviour of IDS. Using the same Kripke frame we show how knowledge and belief in the terms of epistemic linear logic can be achieved

Vidéopoésie

Canadian digital artist and videopoet Valerie LeBlanc and Canadian poet, musician, and videopoet ******** Daniel H. Dugas have been working together since 1990. Daniel H. Dugas was born in Montréal, QC. Poet, videographer, essayist and musician, Dugas has exhibited and participated in exhibitions, festivals and literary events in Canada and internationally. His ninth book of poetry: L’esprit du temps/The Spirit of the Time won the 2016 Antonine-Maillet-Acadie Vie award and the 2018 Éloizes: Artiste de l’année en littérature. daniel.basicbruegel.com | Videos distributed through: vtape.org *********** Pluridisciplinary artist and writer, Valerie LeBlanc was born in Halifax, Nova Scotia. She has worked and presented throughout Canada and internationally. LeBlanc’s first video: Homecoming was collected and screened by the National Gallery of Canada. She is the creator of the MediaPackBoard (MPB), a portable screening / performance device. valerie.basicbruegel.com | Videos distributed through: vtape.org ********** Their specific uniqueness within the videopoetry world also lies in the musicality of speaking two languages. LeBlanc’s first language is English and her second French; and Dugas’ is French with English second. (Sarah Tremlett)This project is supported by the Marilyn I. Walker School of Fine and Performing Arts at Brock University and the New Brunswick Arts Board. / Ce projet est soutenu par le Marilyn I. Walker School of Fine and Performing Arts à Brock University et par le Conseil des arts du Nouveau-Brunswick

Draft crystal structure of the vault shell at 9-A resolution.

Vaults are the largest known cytoplasmic ribonucleoprotein structures and may function in innate immunity. The vault shell self-assembles from 96 copies of major vault protein and encapsulates two other proteins and a small RNA. We crystallized rat liver vaults and several recombinant vaults, all among the largest non-icosahedral particles to have been crystallized. The best crystals thus far were formed from empty vaults built from a cysteine-tag construct of major vault protein (termed cpMVP vaults), diffracting to about 9-A resolution. The asymmetric unit contains a half vault of molecular mass 4.65 MDa. X-ray phasing was initiated by molecular replacement, using density from cryo-electron microscopy (cryo-EM). Phases were improved by density modification, including concentric 24- and 48-fold rotational symmetry averaging. From this, the continuous cryo-EM electron density separated into domain-like blocks. A draft atomic model of cpMVP was fit to this improved density from 15 domain models. Three domains were adapted from a nuclear magnetic resonance substructure. Nine domain models originated in ab initio tertiary structure prediction. Three C-terminal domains were built by fitting poly-alanine to the electron density. Locations of loops in this model provide sites to test vault functions and to exploit vaults as nanocapsules

Food Security Survey: Phase I, Agricultural Production and Land Use Season 2000A

REPUBLIC OF RWANDA, MINISTRY OF AGRICULTURE, ANIMAL RESOURCES, AND FORESTRY, Food Security Research Project (FSRP) and Division of Agricultural Statistics (DSA)food security, food policy, Rwanda, agricultural production, land use, Food Security and Poverty, Q18,