General Rank Research Articles

Structural Vector Autoregressions: Theory of Identification and Algorithms for Inference

Structural vector autoregressions (SVARs) are widely used for policy analysis and to provide stylized facts for dynamic general equilibrium models. Yet there have been no workable rank conditions to ascertain whether an SVAR is globally identified. When identifying restrictions such as long-run restrictions are imposed on impulse responses, there have been no efficient algorithms for small-sample estimation and inference. To fill these important gaps in the literature, this paper makes four contributions. First, we establish general rank conditions for global identification of both overidentified and exactly identified models. Second, we show that these conditions can be checked as a simple matrix-filling exercise and that they apply to a wide class of identifying restrictions, including linear and certain nonlinear restrictions. Third, we establish a very simple rank condition for exactly identified models that amounts to a straightforward counting exercise. Fourth, we develop a number of efficient algorithms for small-sample estimation and inference.

Channel-Optimized Quantum Error Correction

We develop a theory for finding quantum error correction (QEC) procedures which are optimized for given noise channels. Our theory accounts for uncertainties in the noise channel, against which our QEC procedures are robust. We demonstrate, via numerical examples, that our optimized QEC procedures always achieve a higher channel fidelity than the standard error correction method, which is agnostic about the specifics of the channel. This demonstrates the importance of channel characterization before QEC procedures are applied. Our main novel finding is that in the setting of a known noise channel the recovery ancillas are redundant for optimized quantum error correction. We show this using a general rank minimization heuristic and supporting numerical calculations. Therefore, one can further improve the fidelity by utilizing all the available ancillas in the encoding block.

PAH and PCB in soils of Switzerland—status and critical review

The surface soil concentrations (0-20 cm) of the Swiss soil monitoring network (NABO) with 105 observation sites representing all major land use types ranged for the sum of 16 EPA PAH (PAH(16)) from 32 to 8465 microg kg(-1) (median 163 microg kg(-1)), for benzo[a]pyrene (BaP) from 0.5 to 1129 microg kg(-1) (median 13 microg kg(-1)) and for the sum of seven IRMM PCB (PCB(7)) from 0.5 to 12 microg kg(-1) (median 1.6 microg kg(-1)). The legal guide values of Switzerland were exceeded for PAH(16) at only three and for BaP at two sites. The PCB(7) concentrations were clearly below any assessment value. The concentration ranges were overlapping between all land use types. Tendencies for higher concentrations were observed at urban and viticulture sites. The overall measurement precision at repeatability conditions ranged from 1 to 37% RSD for PAH(16), BaP and PCB(7). The median bias for the chemical analysis was around zero for PAH(16), +5% for BaP and -5% for PCB(7) with spreads ranging from less than -20% up to more than +30%. The PAH profiles were clearly dominated by phenanthrene. Stratification by land use revealed a prevalence of benzo[a]pyrene at urban and naphthalene at conservation sites. For PCB, the general congener rank order was PCB no. 153 > 138 > 101 > 180. From a broad correlation screening only PAH(16)/BaP (r = 0.88**) were relevant for practical soil protection. The extensive comparison with other studies was severely biased by the lack of harmonisation, especially concerning sampling depth, sampling support, analytical method and the sum calculation procedure.

Authors who have an impact on candidates' training

<i>The authors consider the influence that a sense of geographical and cultural ties of candidates from different regions has on their theoretical interests. They question the way that this is taken into consideration in psychoanalytic training. The function of theory, both in terms of its transmission and the creation of new knowledge, is explored from this perspective. The results of an Internet survey are presented. The candidate sample for this survey</i> (N = <i>250</i>) <i>was drawn from Europe, Latin America and North America, and candidates were asked to indicate their degree of interest for each of the 55 authors in a given list. The results showed that there were significant differences in the areas of theoretical interest of the candidates depending on the geographical region. Furthermore, what is also significant is how these differences in areas of theoretical interest were linked to those authors who had developed their work in the same geographical region as the candidates. These differences are shown to be connected to the candidates' sense of regional belonging. Data are also presented about which authors have the greatest impact in a given region, along with the influence values of the authors in relation to each one of the regions. Finally, the candidates' interest in each of the authors is specified in terms of a general mean rank and a regional mean rank, thus showing which authors candidates find most interesting in each of the regions. The study concludes by arguing that the results of the investigation enable us to question how psychoanalytic theory is transmitted, and, more specifically, how it is transmitted within institutions at a regional level. It is also suggested that the means be found to uncover the inconsistencies linked to cultural ties. It is proposed that further research be conducted to look more deeply into how cultural differences play a part in the different theoretical languages in the training of psychoanalysts.</i>

Reflection groups and polytopes over finite fields, III

When the standard representation of a crystallographic Coxeter group Γ is reduced modulo an odd prime p, one obtains a finite group G p acting on some orthogonal space over Z p . If Γ has a string diagram, then G p will often be the automorphism group of a finite abstract regular polytope. In parts I and II we established the basics of this construction and enumerated the polytopes associated to groups of rank at most 4, as well as all groups of spherical or Euclidean type. Here we extend the range of our earlier criteria for the polytopality of G p . Building on this we investigate the class of ‘3-infinity’ groups of general rank, and then complete a survey of those locally toroidal polytopes which can be described by our construction.

RANK LOWERING OPERATORS ON GL(n, ℝ)

If one takes the Mellin transform of an automorphic form for GL(n) and then integrates it along the diagonal on GL(n - 1) then one obtains an automorphic form on GL(n - 1). This gives a rank lowering operator. In this paper a more general rank lowering operator is obtained by combining the Mellin transform with a sum of powers of certain fixed differential operators. The analytic continuation of the rank lowering operator is obtained by showing that the spectral expansion consists of sums of Rankin–Selberg L-functions of type GL(n) × GL(n - 1).

Guaranteed Minimum-Rank Solutions of Linear Matrix Equations via Nuclear Norm Minimization

The affine rank minimization problem consists of finding a matrix of minimum rank that satisfies a given system of linear equality constraints. Such problems have appeared in the literature of a diverse set of fields including system identification and control, Euclidean embedding, and collaborative filtering. Although specific instances can often be solved with specialized algorithms, the general affine rank minimization problem is NP-hard because it contains vector cardinality minimization as a special case. In this paper, we show that if a certain restricted isometry property holds for the linear transformation defining the constraints, the minimum-rank solution can be recovered by solving a convex optimization problem, namely, the minimization of the nuclear norm over the given affine space. We present several random ensembles of equations where the restricted isometry property holds with overwhelming probability, provided the codimension of the subspace is sufficiently large. The techniques used in our analysis have strong parallels in the compressed sensing framework. We discuss how affine rank minimization generalizes this preexisting concept and outline a dictionary relating concepts from cardinality minimization to those of rank minimization. We also discuss several algorithmic approaches to minimizing the nuclear norm and illustrate our results with numerical examples.

Rank Aggregation for Automatic Schema Matching

Schema matching is a basic operation of data integration, and several tools for automating it have been proposed and evaluated in the database community. Research in this area reveals that there is no single schema matcher that is guaranteed to succeed in finding a good mapping for all possible domains and, thus, an ensemble of schema matchers should be considered. In this paper, we introduce schema metamatching, a general framework for composing an arbitrary ensemble of schema matchers and generating a list of best ranked schema mappings. Informally, schema metamatching stands for computing a "consensus" ranking of alternative mappings between two schemata, given the "individual" graded rankings provided by several schema matchers. We introduce several algorithms for this problem, varying from adaptations of some standard techniques for general quantitative rank aggregation to novel techniques specific to the problem of schema matching, and to combinations of both. We provide a formal analysis of the applicability and relative performance of these algorithms and evaluate them empirically on a set of real-world schemata

A physically motivated anisotropic tensorial representation of damage with separate functions for void nucleation, growth, and coalescence

A phenomenological anisotropic damage progression formulation for porous ductile metals with second phases is described through mechanisms of void nucleation, growth and coalescence. The model is motivated from fracture mechanisms and microscale physical observations. To describe the creation of new pores, the decohesion at the particle–matrix interface and the fragmentation of second phase particles, the void-crack nucleation equation is related to several microstructural parameters (fracture toughness, length scale parameter, particle size, volume and fraction of second phase), the plastic strain level, and the stress state. Nucleation is represented by a general symmetric second rank tensor, and its components are proportional to the absolute value of the plastic strain rate components. Based on the Rice and Tracey model, void growth is a scalar function of the trace of damage tensor and the positive triaxiality. Like nucleation, coalescence is a second rank tensor governed by the plastic strain rate tensor and the stress state. The coalescence threshold is related to the void length scale for void impingement and void sheet mechanisms. The coupling of damage with the Bammann–Chiesa–Johnson (BCJ) plasticity model is written in the thermodynamic framework and derives from the concept of effective stress assuming the hypothesis of energy equivalence. A full-implicit algorithm is used for the stress integration and the determination of the consistent tangent operator. Finally, macroscale correlations to cast A356 AL alloy and wrought 6061-T6 AL alloy experimental data are completed with predictive void-crack evolution to illustrate the applicability of the anisotropic damage model.

Effect of Iodine Status and other Nutritional Factors on Psychomotor and Cognitive Performance of Filipino Schoolchildren

Until 1998, iodine deficiency was a public health problem in the Philippines. A law entitled "An Act Promoting Salt Iodization Nationwide" (ASIN) has been passed and implemented by the government to eliminate iodine deficiency. The contribution of salt iodization, as well as dietary, health, and environmental factors, to improving the intellectual performance of Filipino schoolchildren remains to be determined. The objectives of the study were to determine the relationship between iodine status and levels of psychomotor and cognitive performance in first-grade children aged 6 to 10 years, and to examine the extent to which dietary, biochemical, health, and environmental factors contribute to children's mental performance. Two hundred ninety children in six classroom sections from a public school in Manila were examined by measurement of urinary iodine excretion (UIE) and thyroid palpation. The median UIE level for each section was determined. Sixty-five children classified as iodine deficient (UIE < 90 microg/L with grade 1 goiter, n = 34) and non-iodine deficient (UIE > 100 microg/L without goiter, n = 31) were given psychomotor and cognitive function tests (Bender-Gestalt and Raven's Colored Progressive Matrices). Scores from the two tests were used to determine each child's general ability percentile rank. Other variables examined were dietary intake (% RDA of nutrients ingested based on two nonconsecutive 24-hour recalls); deficiencies in iron, vitamin A, and selenium; parasitic infection; coliform contamination of drinking water; household use of iodized salt; illness in the past 2 weeks; and wasting and stunting. Children whose general ability scores were at or above the 50th percentile had higher UIE levels, but the relationship was not significant. Children from sections with higher median UIE levels had higher percentile ranks for general ability (p = .002). Backward logistic regression showed that the variance in deficient and adequate mental performance was explained by dietary intakes that met > or = 80% of the RDA for energy, protein, thiamin, and riboflavin; the use of iodized salt; child's iodine status; and stunting (R2 = .520, p = .0016). Higher class median UIE was associated with better psychomotor and cognitive performance in children who were tested. Factors that contributed to better performance include higher intakes of energy, protein, thiamin, and riboflavin; household use of iodized salt; normal iodine status; and absence of stunting or chronic malnutrition. Salt iodization, accompanied by adequate intakes of energy, protein, and foods rich in thiamin and riboflavin, can contribute to improved mental performance in Filipino schoolchildren. Longer-term factors that can contribute to improved performance are achievement of normal iodine status and elimination of protein-energy malnutrition.

On the Support Problem for Drinfeld Modules

Let Φ be a Drinfeld A-module over an A-field K of generic characteristic. We will prove the following two results which are analogous to ones in number fields. Case 1. Φ is of rank one. Suppose that P and Q are two nontorsion points in Φ(K). If for any element a ∈ A and almost all prime ideals 𝒫 in 𝔸 one has that Φ a (P) ≡ 0 (mod 𝒫) ⇒ Φ a (Q) ≡ 0 (mod 𝒫), then Q = Φ m (P) for some m ∈ A. Case 2. Φ is of general rank ≥ 1. Let x, y ∈ Φ(K) be two K-rational points. Denote 𝒪 = End K (Φ) which is commutative and Λ = 𝒪 · y which is a cyclic 𝒪-module. Let red v :Φ(K) → Φ(k v ) be the reduction map at a place v of K with residue field k v . If red v (x) ∈ red v (Λ) for almost all places v of K. Then f(x) = g(y), for some nonzero elements f and g in 𝒪.

New RP‐HPLC Method for the Estimation of 6‐Mercaptopurine in Rat Plasma and Various Tissue Homogenates

A reversed‐phase high performance liquid chromatography (HPLC) method was developed to determine 6‐mercaptopurine (6‐MP) in plasma and tissue homogenates of rats in the present study. A known quantity of the drug and internal standard (metronidazole) was spiked in rat plasma and tissue extracts in a range of 50–1000 ng/mL and 100–1000 ng/mL. The spiked plasma samples were deproteinized using a methanol and acetonitrile mixture (1∶1, v/v) and centrifuged. The supernatant was collected and analyzed for the drug content. A Shimadzu system with Thermosil® C18 (5 µm, 25 cm×4.6 mm i.d.) column was used for the analysis. A mixture of 0.01 M KH2PO4 buffer∶acetonitrile (80∶20, v/v) was used as a mobile phase at a flow rate of 1 mL/min. Each sample containing 20 µL was injected through a Rheodyne injector, and the effluent was monitored at 325 nm. The method was applied to determine pharmacokinetic parameters and biodistribution of a drug in tissues. The retention times were 4.0 min and 6.2 min for drug and internal standard, respectively. The plot of ratio of area of 6‐MP and IS vs. concentration of 6‐MP in ng/mL was found linear in the range of 50–1000 ng/mL in plasma and 100–1000 ng/mL in all tissues. High correlation coefficients were observed with plasma (0.998), liver (0.999), lung (0.999), kidney (0.999), heart (0.993), and spleen (0.990). The limit of detection in plasma was 38 ng/mL and 66–89 ng/mL in various tissues. The performed “t” test for the estimated concentration in recovery studies indicate no significant difference between the added and estimated concentration proving the accuracy and low % RSD values indicate the precision of the method. On the basis of total 6‐MP plasma concentrations as determined by HPLC, the drug showed the AUC of 2098.76±351.2 ng · h/mL, Cmax of 1437.27±214.84 ng/mL with Tmax of 30 min, Vss of 0.27 mL/kg, and total body clearance of 2.32 mL/h/kg in pharmacokinetic studies, by treating rats with 6‐MP at a dose of 5 mg/kg intravenously. The biodistribution studies showed that the drug was more concentrated in the liver and kidney than other organs, with a general rank order of liver>kidney>heart>spleen>lung. The above study showed great potential of the reported method to estimate 6‐MP in plasma and tissues of rats and may be a substitute for other methods, which are complex, time consuming, and consume high quantities of organic solvents for estimation.

Pharmacological Characterization of Endocannabinoid Transport and Fatty Acid Amide Hydrolase Inhibitors

: 1. The mechanism of anandamide uptake and disposal has been an issue of considerable debate in the cannabinoid field. Several compounds have been reported to inhibit anandamide uptake or fatty acid amide hydrolase (FAAH; the primary catabolic enzyme of anandamide) activity with varying degrees of potency and selectivity. We recently reported the first evidence of a binding site involved in the uptake of endocannabinoids that is independent from FAAH. There are no direct comparisons of purported selective inhibitory compounds in common assay conditions measuring anandamide uptake, FAAH activity and binding activity. 2. A subset of compounds reported in the literature were tested in our laboratory under common assay conditions to measure their ability to (a) inhibit [(14)C]-anandamide uptake in cells containing (RBL-2H3) or cells lacking (HeLa) FAAH, (b) inhibit purified FAAH hydrolytic activity, and (c) inhibit binding to a putative binding site involved in endocannabinoid transport in both RBL and HeLa cell membranes. 3. Under these conditions, nearly all compounds tested inhibited (a) uptake of [(14)C]-anandamide, (b) enzyme activity in purified FAAH preparations, and (c) radioligand binding of [(3)H]-LY2183240 in RBL and HeLa plasma membrane preparations. General rank order potency was preserved within the three assays. However, concentration response curves were right-shifted for functional [(14)C]-anandamide uptake in HeLa (FAAH(-/-)) cells. 4. A more direct comparison of multiple inhibitors could be made in these three assay systems performed in the same laboratory, revealing more information about the selectivity of these compounds and the relationship between the putative endocannabinoid transport protein and FAAH. At least two separate proteins appear to be involved in uptake and degradation of anandamide. The most potent inhibitory compounds were right-shifted when transport was measured in HeLa (FAAH(-/-)) cells suggesting a requirement for a direct interaction with the FAAH protein to maintain high affinity binding of anandamide or inhibitors to the putative anandamide transport protein.

Insect pests' incidence and variations due to forest landscape degradation in the humid forest zone of Southern Cameroon: farmers' perception and need for adopting an integrated pest management strategy

Group surveys were conducted in five villages in each of the three resource-use zones of the humid forest zone of Southern Cameroon, to assess insect pests’ incidence and the variation due to forest landscape degradation in the agricultural production systems. 389 farmers were interviewed. The results show that: (1) In annual crop systems, insect pests in general rank together with vertebrate pests and diseases amongst the most important agronomic constraints. No differences were found between the intensification zones, except for weeds, which appeared to be a greater constraint in the slightly degraded area. Within the insect pest, the greatest damage to crops according to farmers originated from borers and scales, followed by variegated grasshopper. Only the termites showed a difference between zones - the problem being greatest in the high-degraded areas. (2) In the young perennial crop systems, all the categories of agronomic constraints were equally important. Within the insect pest, mirids were identified as the greatest constraint, followed by borers and caterpillars. There were more variations in the responses according to zones compared to annual crops. Termites and scales were relatively more important in the high-degraded area. In term of control strategy, we recommended an integrated pest management.

Variability in mRNA expression of ABC- and SLC-transporters in human intestinal cells: Comparison between human segments and Caco-2 cells

The Caco-2 cell monolayer model is widely used as a tool for evaluating human intestinal permeability and interaction with transporters. Therefore, we determined mRNA levels for 15 of the most frequently studied uptake and efflux transporters (MDR1, MRP2–3, BCRP, OCTN2, PepT1, OATP-B, OATP8, OCT1–3, OAT1–3, MCT1) using real-time PCR in Caco-2 cells and in human jejunum and colon. The expression levels in the Caco-2 cells did not significantly vary between different passages (p29–43) and batches for any of the genes measured. However, levels increased with culture time (1–5 weeks) for PepT1, MDR1, MRP2, OATP-B and BCRP. The general rank order of the gene expression levels in Caco-2 cells was established as follows: MRP2 > OATP-B > PepT1 ≫ MDR1 > MCT1 ≈ MRP3 ≈ BCRP ≈ OCTN2 ≫ OCT3 > OCT1 > OAT2. Four genes were absent: OATP8, OCT2, OAT1, and OAT3. Ranking of 11 expressed genes showed a significant correlation between human jejunum and 2–5-week-old Caco-2 cells. The expression profile in colon was, however, very different compared to both Caco-2 cells and jejunum. We conclude that the Caco-2 cells in our hands express similar transporters as the human jejunum, but are different from colon, indicating their usefulness for obtaining small intestinal transport data. In addition, we also suggest that cells with a well-defined range of culture ages should be used to minimize variability in data from experiments and even erroneous conclusions.

A Note on Sample Size Determination for a Nonparametric Test of Location

Sample size determination methods are considered for hypothesis testing about location parameters of two continuous distributions using independent random samples and the Mann–Whitney–Wilcoxon (MWW) test, for a specified shift, size, and power. These methods are based on the so-called “Noether's formula,” derived from a normal approximation to the power of the MWW test, and a pilot sample from each of the distributions. Compared with alternate methods, including the one using bootstrap similar to that of Hamilton and Collings (1991) the new methods are shown to be at least as good in terms of accuracy and substantially more efficient in terms of speed and variability. The simpler method, using linearly smoothed empirical cdf's of the pilot samples and requiring no bootstrapping, is recommended for practical use. Extensions and adaptations for obtaining an upper confidence bound on the sample size and to general linear rank tests are indicated.

FORMULATION AND EVALUATION OF CROCONAZOL HYDROCHLORIDE TOPICAL GELS

This study was designed to evaluate different polymers for their suitability as a vehicles for topical drug delivery systems. Croconazol hydrochloride is an azol derivative used as antimycotic agent. It was incorporated in this vehicles as a gel forms in a concentration of 1.0% w/w. Polymers used in this study are methylcellulose (MC), Tylose (Ty), Polyvinyl alcohol (PVA), Pluronic F-127 (pl. F-127), Polyethylene glycol (PEG), Carbopol 974P (Carb.) and Eudispert mv. (Eud). They were used in a suitable concentration for gel formulation. In-vitro release characteristics of the drug from different gels were carried out using dialysis membrane in phosphate buffer pH 5.2. The release data were treated with various kinetic principles to assess the relevant parameters. The general rank order of Croconazol hydrochloride release from the prepared gel were MC > Ty > pl. F-127 > PVA > Carb > Eud > PEG. The results showed that, the release of drug from the prepared gels obeyed the diffusion model (Higuchi’s equation). Some kinetic parameters were calculated such as diffusion coefficient, permeability coefficient and the partition coefficient. The results indicated a direct dependence of the release rate on the diffusion coefficient. The influence of initial drug concentration (0.5, 1.0 and 2.0% w/w), and pl F-127 concentration (20, 25, 30% w/v) on the release patterns was studied. The obtained data revealed an inverse correlation between the drug release rate and the pluronic F-127 concentration and a direct correlation between the drug release rate and the initial drug concentration. The anti-fungal activity of the different gel formulations was evaluated by agar-cup plate technique using five fungal species. The results obtained indicated that, all gel formulations have good anti-fungal activities.

An alternative Ca2+‐dependent mechanism of neuroprotection by the metalloporphyrin class of superoxide dismutase mimetics

This study challenges the conventional view that metalloporphyrins protect cultured cortical neurons in models of cerebral ischemia by acting as intracellular catalytic antioxidants [superoxide dismutase (SOD) mimetics]. High SOD-active Mn(III)porphyrins meso-substituted with N,N'-dimethylimidazolium or N-alkylpyridinium groups did not protect neurons against oxygen-glucose deprivation (OGD), although lower SOD-active and -inactive para isomers protected against N-methyl-D-aspartate (NMDA) exposure. Mn(III)meso-tetrakis(4-benzoic acid)porphyrin (Mn(III)TBAP), as well as SOD-inactive metalloTBAPs and other phenyl ring- or beta-substituted metalloporphyrins that contained redox-insensitive metals, protected cultures against OGD and NMDA neurotoxicity. Crucially, neuroprotective metalloporphyrins suppressed OGD- or NMDA-induced rises in intracellular Ca2+ concentration in the same general rank order as observed for neuroprotection. Results from paraquat toxicity, intracellular fluorescence quenching, electrophysiology, mitochondrial Ca2+, and spontaneous synaptic activity experiments suggest a model in which metalloporphyrins, acting at the plasma membrane, protect neurons against OGD by suppressing postsynaptic NMDA receptor-mediated Ca2+ rises, thereby indirectly preventing accumulation of neurotoxic mitochondrial Ca2+ levels. Though neuroprotective in a manner not originally intended, SOD-inactive metalloporphyrins may represent promising therapeutic agents in diseases such as cerebral ischemia, in which Ca2+ toxicity is implicated. Conventional syntheses aimed at improving the catalytic antioxidant capability and/or intracellular access of metalloporphyrins may not yield improved efficacy in some disease models.

Frame expansions for Gabor multipliers

Discrete Gabor multipliers are composed of rank one operators. We shall prove, in the case of rank one projection operators, that the generating operators for such multipliers are either Riesz bases (exact frames) or not frames for their closed linear spans. The same dichotomy conclusion is valid for general rank one operators under mild and natural conditions. This is relevant since discrete Gabor multipliers have an emerging role in communications, radar, and waveform design, where redundant frame decompositions are increasingly applicable.

A representation of a comonotone- [formula omitted]-additive and monotone functional by two Sugeno integrals

There is obtained a representation of a comonotone- ◯ ∨ -additive, weak ◯ ∧ -homogeneous and monotone functional L (defined on the class of functions on finite set) as a symmetric maximum of two Sugeno integrals. This representation is a generalization of certain previous results, which are useful for cumulative prospect theory. As a consequence of a result on general fuzzy rank and sign-dependent functionals considered on functions defined on the infinitely countable basic set X it is obtained that the symmetric Sugeno integral is comonotone- ◯ ∨ -additive functional on the class of functions with finite support.