Noise-based logic: Binary, multi-valued, or fuzzy, with optional superposition of logic states

A new type of deterministic (non-probabilistic) computer logic system inspired by the stochasticity of brain signals is shown. The distinct values are represented by independent stochastic processes: independent voltage (or current) noises. The orthogonality of these processes provides a natural way to construct binary or multi-valued logic circuitry with arbitrary number N of logic values by using analog circuitry. Moreover, the logic values on a single wire can be made a (weighted) superposition of the N distinct logic values. Fuzzy logic is also naturally represented by a two-component superposition within the binary case (N=2). Error propagation and accumulation are suppressed. Other relevant advantages are reduced energy dissipation and leakage current problems, and robustness against circuit noise and background noises such as 1/f, Johnson, shot and crosstalk noise. Variability problems are also nonexistent because the logic value is an AC signal. A similar logic system can be built with orthogonal sinusoidal signals (different frequency or orthogonal phase) however that has an extra 1/N type slowdown compared to the noise-based logic system with increasing number of N furthermore it is less robust against time delay effects than the noise-based counterpart.Comment: Accepted for publication by Physics Letters A, on December 23, 200

Resolving the extragalactic hard X-ray background

The origin of the hard (2-10 keV) X-ray background has remained mysterious for over 35 years. Most of the soft (0.5-2 keV) X-ray background has been resolved into discrete sources, which are primarily quasars; however, these sources do not have the flat spectral shape required to match the X-ray background spectrum. Here we report the results of an X-ray survey 30 times more sensitive than previous studies in the hard band and four times more sensitive in the soft band. The sources detected in our survey account for at least 75 per cent of the hard X-ray background. The mean X-ray spectrum of these sources is in good agreement with that of the background. The X-ray emission from the majority of the detected sources is unambiguously associated with either the nuclei of otherwise normal bright galaxies or optically faint sources, which could either be active nuclei of dust enshrouded galaxies or the first quasars at very high redshifts.Comment: Nature article in pres

Dos especies de garrapatas del g\ue9nero Amblyomma (Acari: Ixodidae) en perros del estado Aragua, Venezuela

Manzanilla J, Garc\ueda ME, Moissant E, Garc\ueda FA, Tortolero E. 2002. Two species of ticks of the genus Amblyomma (Acari: Ixodidae) on dogs of the Aragua state, Venezuela. Entomotropica 17(2):177-180. The first report of Amblyomma maculatum and A. parvum collected from Rottweiler and crossbred dogs, in Aragua state are presented. This is the first report of A. parvum on dogs in Venezuela.Manzanilla J, Garc\ueda ME, Moissant E, Garc\ueda FA, Tortolero E. 2002. Dos especies de garrapatas del g\ue9nero Amblyomma (Acari: Ixodidae) en perros del estado Aragua, Venezuela. Entomotropica 17(2):177-180. Se presenta el primer registro de Amblyomma maculatum y A. parvum para el estado Aragua, sobre perros de la raza Rottweiler y mestizo respectivamente. Es el primer registro de A. parvum sobre caninos en Venezuel

Pathological Investigation of Congenital Bicuspid Aortic Valve Stenosis, Compared with Atherosclerotic Tricuspid Aortic Valve Stenosis and Congenital Bicuspid Aortic Valve Regurgitation

Congenital bicuspid aortic valve (CBAV) is the main cause of aortic stenosis (AS) in young adults. However, the histopathological features of AS in patients with CBAV have not been fully investigated.We examined specimens of aortic valve leaflets obtained from patients who had undergone aortic valve re/placement at our institution for severe AS with CBAV (n = 24, CBAV-AS group), severe AS with tricuspid aortic valve (n = 24, TAV-AS group), and severe aortic regurgitation (AR) with CBAV (n = 24, CBAV-AR group). We compared the histopathological features among the three groups. Pathological features were classified using semi-quantitative methods (graded on a scale 0 to 3) by experienced pathologists without knowledge of the patients' backgrounds. The severity of inflammation, neovascularization, and calcium and cholesterol deposition did not differ between the CBAV-AS and TAV-AS groups, and these four parameters were less marked in the CBAV-AR group than in the CBAV-AS (all p<0.01). Meanwhile, the grade of valvular fibrosis was greater in the CBAV-AS group, compared with the TAV-AS and CBAV-AR groups (both p<0.01). In AS patients, thickness of fibrotic lesions was greater on the aortic side than on the ventricular side (both p<0.01). Meanwhile, thickness of fibrotic lesions was comparable between the aortic and ventricular sides in CBAV-AR patients (p = 0.35).Valvular fibrosis, especially on the aortic side, was greater in patients with CBAV-AS than in those without, suggesting a difference in the pathogenesis of AS between CBAV and TAV

The Universe Was Reionized Twice

We show the universe was reionized twice, first at z~15-16 and second at z~6. Such an outcome appears inevitable, when normalizing to two well determined observational measurements, namely, the epoch of the final cosmological reionization at z~6 and the density fluctuations at z~6, which in turn are tight ly constrained by Lyman alpha forest observations at z~3. These two observations most importantly fix the product of star formation efficiency and ionizing photon escape fraction from galaxies at high redshift. To the extent that the relative star formation efficiencies in gaseous minihalos with H2 cooling and large halos with atomic cooling at high redshift are still unknown, the primary source for the first reionization could be Pop III stars either in minihalos or in large halos. We show that gas in minihalos can be cooled efficiently by H2 molecules and star formation can continue to take place largely unimpeded throughout the first reionization period, thanks to two new mechanisms for generating a high X-ray background during the Pop III era, put forth here. Moreover, an important process for producing a large number of H2 molecules in relic HII regions of Pop III galaxies, first pointed out by Ricotti, Gnedin, & Shull, is quantified here. It is shown that the Lyman-Werner background may never build up during the Pop III era. The long cosmological reionization and reheating history is complex. We discuss a wide range of implications and possible tests for this new reionization picture. In particular, Thomson scattering optical depth is increased to 0.10 +- 0.03, compared to 0.027 for the case of only one rapid reionization at z=6. Upcoming Microwave Anisotropy Probe observation of the polarization of the cosmic microwave background should be able to distinguish between these two scenarios.Comment: submitted to ApJ, 69 pages, substantial revision made and conclusions strengthene

Effect of NaCl on physiological, biochemical, and ionic parameters of naked oat (Avena nuda L.) line Bayou1

Oat (Avena nuda L.) is a globally important cereal crop grown for its nutritious grains and is considered as moderately salt-tolerant. Studying salinity tolerant mechanisms of oats could assist breeders in increasing oat production and their economic income in salt-affected areas, as the total amount of saline land in the world is still increasing. The present study was carried out to better understand the salt tolerance mechanism of the naked oat line Bayou1. A soil experiment was conducted on 17 days-old Bayou1 seedlings treated with varying concentrations of NaCl for a period of 12 days. Bayou1 plants grew optimally when treated with 50 mM NaCl, demonstrating their salinity tolerance. Reduced water uptake, decreased Ca2+, Mg2+, K+, and guaiacol peroxidase activity, as well as increased Na+ concentration in leaves, all contributed to a reduction in shoot growth. However, the damage to ionic homeostasis caused by increased Na+ concentrations and decreased K+ concentrations in the roots of Bayou1 did not inhibit its root growth, indicating that the main salt-tolerant mechanism in Bayou1 existed in its roots. Further, a hydroponic experiment found that increasing Na+ concentration in root cell sap enhanced root growth, while maintaining the integrity of root cell membranes. The accumulated Na+ may have facilitated the root growth of Bayou1 exposed to NaCl by effectively adjusting cellular osmotic potential, thereby ensuring root cell turgor and expansion

Accurate large-signal equivalent circuit of surface channel diamond FETs based on the Chalmers model

The paper presents a large-signal nonlinear circuit-oriented model for polycrystalline and single-crystal H-terminated diamond MESFETs implemented within the Agilent ADS design suite. The DC characteristics of such devices suggest that the channel free charge control law may be modeled using the same strategy adopted for III-V HEMTs. For this reason, the well-known nonlinear Chalmers (Angelov) circuit model was chosen as the starting point for the development of the present non-linear diamond MESFET model. Model fitting was performed against DC and multibias small signal measurements, with good agreement. Model validations versus large-signal (power) measurements point out the accuracy of the proposed approach to simulate the behavior of H-terminated diamond MESFETs under large-signal operatio

Value of delayed hypointensity and delayed enhancing rim in magnetic resonance imaging diagnosis of small hepatocellular carcinoma in the cirrhotic liver

Purpose: To determine the diagnostic utility of delayed hypointensity and delayed enhancing rim on magnetic resonance imaging (MRI) as indicators of hepatocellular carcinoma (HCC) in arterially enhancing nodules ≤5 cm in the cirrhotic liver and determine the features that best predict HCC. Materials and Methods: Gadolinium-enhanced MRI studies performed from January 2001 to December 2004 in patients with cirrhosis were evaluated for arterially enhancing nodules measuring ≤5 cm. Verification was via explant correlation, biopsy, or imaging follow-up. Sensitivity and specificity of diagnostic features of HCC were calculated. Features predictive of HCC were determined using the Generalized Estimating Equation approach. Results: In all, 116 arterially enhancing nodules were identified in 80 patients (<2 cm: n = 79, 2–5 cm n = 37). Sensitivity and specificity of delayed hypointensity for HCC measuring ≤5 cm, 2–5 cm, and <2 cm were 0.54 (40 of 74) and 0.86 (36 of 42); 0.72 (23 of 32) and 0.80 (4 of 5); and 0.41 (17 of 42) and 0.87 (32 of 37). For the delayed enhancing rim sensitivity and specificity were 0.64 (47 of 74) and 0.86 (36 of 42); 0.75 (24 of 32) and 1.0 (5 of 5); and 0.55 (23 of 42) and 0.83 (31 of 37), respectively. Lesion size (≥2 cm) and delayed enhancing rim, as main features and their interaction, were the most significant predictors of HCC. Conclusion: Delayed hypointensity and enhancing rim improve the specificity of diagnosis of HCC of all sizes but are seen less frequently in small (<2 cm) HCC. Nodule size (≥2 cm) and delayed enhancing rim are the strongest predictors of HCC. J. Magn. Reson. Imaging 2010;32:360–366. © 2010 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77511/1/22271_ftp.pd

Des-gamma-carboxyl prothrombin is associated with tumor angiogenesis in hepatocellular carcinoma

Background and Aim: Hepatocellular carcinoma (HCC) is a hypervascular tumor, and angiogenesis plays an important role in its development. Previously, we demonstrated that des-gamma-carboxyl prothrombin (DCP) promotes both cell proliferation and migration of human umbilical vein endothelial cells (HUVECs) by inducing the autophosphorylation of kinase insert domain receptor (KDR). In the present study, DCP-associated tumor angiogenesis was assessed by comparing hypovascular and common hypervascular HCC. Methods: The solitary HCCs of 827 patients were classified into two groups according to the tumor density at the arterial phase of a dynamic computed tomography scan; the initial clinical data of patients with the hyper- and hypovascular types were compared. The HCC tissues from 95 tumors were analyzed by immunohistochemical staining for DCP and phosphorylated KDR, and intratumoral microvessel density (MVD) was analyzed to evaluate microvessel angiogenesis. Results: The serum DCP levels (320 +/- 3532 mAU/mL) and tumor size (18.4 +/- 9.0 mm) of patients with hypervascular HCC were significantly greater than those with hypovascular HCC (38.7 +/- 80 mAU/mL and 14.6 +/- 5.2 mm, P < 0.001). Immunohistochemical analysis revealed that the expressions of DCP and phospho-KDR were significantly greater in hypervascular HCC (71.4% and 31.0%, respectively) than in hypovascular HCC (7.6% and 5.7%, respectively). Intratumoral MVD was significantly correlated with DCP (r = 0.48, P < 0.0001). Conclusions: des-gamma-carboxyl prothrombin production is associated with tumor angiogenesis in HCC