The standard model of particle physics contains parameters-such as particle masses-whose origins are still unknown and which cannot be predicted, but whose values are constrained through their ...interactions. In particular, the masses of the top quark (Mt) and W boson (MW) constrain the mass of the long-hypothesized, but thus far not observed, Higgs boson. A precise measurement of Mt can therefore indicate where to look for the Higgs, and indeed whether the hypothesis of a standard model Higgs is consistent with experimental data. As top quarks are produced in pairs and decay in only about 10-24 s into various final states, reconstructing their masses from their decay products is very challenging. Here we report a technique that extracts more information from each top-quark event and yields a greatly improved precision (of ± 5.3 GeV/c2) when compared to previous measurements. When our new result is combined with our published measurement in a complementary decay mode and with the only other measurements available, the new world average for Mt becomes 178.0 ± 4.3 GeV/c2. As a result, the most likely Higgs mass increases from the experimentally excluded value of 96 to 117 GeV/c2, which is beyond current experimental sensitivity. The upper limit on the Higgs mass at the 95% confidence level is raised from 219 to 251 GeV/c2.
On polarization of spherical codes and designs Boyvalenkov, P.G.; Dragnev, P.D.; Hardin, D.P. ...
Journal of mathematical analysis and applications,
08/2023, Letnik:
524, Številka:
1
Journal Article
Recenzirano
Odprti dostop
In this article we investigate the N-point min-max and max-min polarization problems on the sphere for a large class of potentials in Rn. We derive universal lower and upper bounds on the ...polarization of spherical designs of fixed dimension, strength, and cardinality. The bounds are universal in the sense that they are a convex combination of potential function evaluations with nodes and weights independent of the class of potentials. As a consequence of our lower bounds, we obtain the Fazekas-Levenshtein bounds on the covering radius of spherical designs. Utilizing the existence of spherical designs, our polarization bounds are extended to general configurations. As examples we completely solve the min-max polarization problem for 120 points on S3 and show that the 600-cell is universally optimal for that problem. We also provide alternative methods for solving the max-min polarization problem when the number of points N does not exceed the dimension n and when N=n+1. We further show that the cross-polytope has the best max-min polarization constant among all spherical 2-designs of N=2n points for n=2,3,4; for n≥5, this statement is conditional on a well-known conjecture that the cross-polytope has the best covering radius. This max-min optimality is also established for all so-called centered codes.
Prostate cancer remains the most common non-cutaneous malignancy among men in the United States. To discover potential serum-based biomarkers for high-risk prostate cancer, we performed a ...high-multiplex immunoassay utilizing patient-matched pre-operative and post-operative serum samples from ten men with high-grade and high-volume prostate cancer. Our study identified six (CASP8, MSLN, FGFBP1, ICOSLG, TIE2 and S100A4) out of 174 proteins that were significantly decreased after radical prostatectomy. High levels of CASP8 were detected in pre-operative serum samples when compared to post-operative serum samples and serum samples from patients with benign prostate hyperplasia (BPH). By immunohistochemistry, CASP8 protein was expressed at higher levels in prostate cancer tissues compared to non-cancerous and BPH tissues. Likewise, CASP8 mRNA expression was significantly upregulated in prostate cancer when compared to benign prostate tissues in four independent clinical datasets. In addition, mRNA levels of CASP8 were higher in patients with recurrent prostate cancer when compared to patients with non-recurrent prostate cancer and high expression of CASP8 was associated with worse disease-free survival and overall survival in renal cancer. Together, our results suggest that CASP8 may potentially serve as a biomarker for high-risk prostate cancer and possibly renal cancer.
QSAR modeling of the antimalarial activity of two strains D6 and NF54 of
Plasmodium falciparum for a diverse set of organic compounds is presented. Satisfactory multilinear regression models (
R
2
=
...0.84 and 0.89) were obtained for D6 and NF54 using molecular structural descriptors calculated solely from the structure of a compound using the CODESSA PRO software.
CODESSA PRO Approach: log
IC
50
(D6 or NF54)
=
f
(molecular structural descriptor).
A quantitative structure–activity relationship (QSAR) modeling of the antimalarial activity of two diverse sets of compounds for each of two strains D6 and NF54 of
Plasmodium falciparum is presented. The molecular structural features of compounds are presented by molecular descriptors (geometrical, topological, quantum mechanical, and electronic) calculated using the CODESSA PRO software. Satisfactory multilinear regression models were obtained for data sets of the D6 and NF54 strains, with
R
2
=
0.84 and 0.89, respectively. The models were also satisfactorily validated internally. The descriptors involved in these equations were related to the mechanism of antimalarial protection.
We study the production of the exotic charged charmonium-like state $Z_c^{\pm}(3900)$ in $p \bar p$ collisions through the sequential process $\psi(4260) \rightarrow Z_c^{\pm}(3900) \pi^{\mp}$, ...$Z_c^{\pm}(3900) \rightarrow J/\psi \pi^{\pm}$. Using the subsample of candidates originating from semi-inclusive weak decays of $b$-flavored hadrons, we measure the invariant mass and natural width to be $M=3902.6^{+5.2}_{-5.0}{\rm \thinspace (stat)}^{+3.3}_{-1.4}{\rm \thinspace (syst)}$ MeV and $\Gamma=32 ^{+28}_{-21}{\rm \thinspace (stat)} ^{+26}_{-7}{\rm \thinspace (syst)}$ MeV, respectively. We search for prompt production of the $Z_c^{\pm}(3900)$ through the same sequential process. No significant signal is observed, and we set an upper limit of 0.66 at the 95\% credibility level on the ratio of prompt production to the production via $b$-hadron decays. The study is based on $10.4~\rm{fb^{-1}}$ of $p \overline p $ collision data collected by the D0 experiment at the Fermilab Tevatron collider.
We present a search for the production of a heavy gauge boson, W′, that decays to third-generation quarks, by D0 Collaboration in pp¯ collisions at s=1.96 TeV. We set 95% confidence level upper ...limits on the production cross section times branching fraction. For the first time, we set limits for arbitrary combinations of left- and right-handed couplings of the W′ boson to fermions. For couplings with the same strength as for the standard model W boson, we set the following limits, assuming that there are right-handed neutrinos νR for all three generations with M(W′)>m(νR): M(W′)>863 GeV for purely left-handed couplings, M(W′)>885 GeV for purely right-handed couplings, and M(W′)>916 GeV if both left- and right-handed couplings are present. The limit for right-handed couplings improves for M(W′)<m(νR) to M(W′)>890 GeV.
Sodium manganates with nominal composition Na2/3MnO2 were prepared by solid state reaction between Na2CO3 and MnCO3 at 1000 °C. The composition and structure of NaxMnO2 were controlled by the rate of ...cooling from the temperature of preparation. This is a consequence of the capability of Na2/3MnO2 to accommodate over-stoichiometric Mn4+ ions up to 12.5%. Structural characterization was carried out by XRD powder diffractions, TEM analysis and Raman spectroscopy. The composition and oxidation state of manganese were determined by chemical analysis and magnetic susceptibility measurements. The manganese distribution in the layers was analysed using electron paramagnetic resonance (EPR) spectroscopy. By quenching from 1000 °C, the orthorhombic distorted modification is stabilized. A phase separation into orthorhombic and hexagonal modifications takes place when Na2/3MnO2 is slow cooled. The structure changes are concomitant with an increase in the oxidation state of Mn. The over-stoichiometric Mn4+ ions are accommodated in the hexagonal modification by creation of vacancies in the MnO2-layers.
Layered Mn5O8 is considered as low-cost and high-voltage electrode materials for storing Na+ ions in aqueous media. Herein we provide the first report on the intercalation of Li+ and Mg2+ ions into ...layered Mn5O8 in non-aqueous electrolytes. The layered oxide Mn5O8 is simply prepared by a thermal decomposition of freshly precipitated γ-MnOOH at 500 °C for a short heating time. The morphology of Mn5O8 consists of well-crystalized nanoparticles with rod-like shape. The intercalation properties of Mn5O8 are examined galvanostatically in half lithium-ion cells. Two type of electrolytes are utilized: lithium and magnesium electrolytes containing 1 M LiPF6 in EC:DMC and 0.5 M MgTFSI in diglyme. Because of the layered structure, specific morphology and mixed oxidation states of manganese ions, layered Mn5O8 is able to intercalate reversibly and in high-amount both Li+ and Mg2+ ions in lithium and magnesium electrolytes. In lithium electrolyte, Mn5O8 exhibits high specific capacity (about 180 mAh/g at C/20), excellent rate capability (about 120 mAh/g at C1) and good cycling stability (the Coulombic efficiency more than 99% at C1). The mechanism of the electrochemical reaction is discussed on the basis of ex-situ HR-TEM and electron paramagnetic resonance spectroscopy (EPR). The storage capability of Mn5O8 will, most probably, be of significance for understanding the electrochemical behavior of layered Mn-based oxides in non-aqueous electrolyte.
•Layered Mn5O8 is simply prepared by thermal decomposition of γ-MnOOH.•The Mn5O8 consists of well-crystallized rod-like nanoparticles.•A first report on the Li+ and Mg2+ storage of Mn5O8 in non-aqueous electrolytes.•Mn5O8 exhibits high specific capacity and excellent rate capability.•Ion intercalation causes a transformation from the layered into spinel structure.
•MRI simulation was utilized to measure texture dependence on MR acquisition details.•Texture was measured on a digital brain phantom and clinical brain images.•Texture depends on noise, ...reconstruction algorithm, and parallel imaging R-factor.•Some texture features can be very different from the ground truth values.•Texture features are more or less robust and some predict high vs low grade glioma.
The purpose of this study was to examine the dependence of image texture features on MR acquisition parameters and reconstruction using a digital MR imaging phantom. MR signal was simulated in a parallel imaging radiofrequency coil setting as well as a single element volume coil setting, with varying levels of acquisition noise, three acceleration factors, and four image reconstruction algorithms. Twenty-six texture features were measured on the simulated images, ground truth images, and clinical brain images. Subtle algorithm-dependent errors were observed on reconstructed phantom images, even in the absence of added noise. Sources of image error include Gibbs ringing at image edge gradients (tissue interfaces) and well-known artifacts due to high acceleration; two of the iterative reconstruction algorithms studied were able to mitigate these image errors. The difference of the texture features from ground truth, and their variance over reconstruction algorithm and parallel imaging acceleration factor, were compared to the clinical “effect size”, i.e., the feature difference between high- and low-grade tumors on T1- and T2-weighted brain MR images of twenty glioma patients. The measured feature error (difference from ground truth) was small for some features, but substantial for others. The feature variance due to reconstruction algorithm and acceleration factor were generally smaller than the clinical effect size. Certain texture features may be preserved by MR imaging, but adequate precautions need to be taken regarding their validity and reliability. We present a general simulation framework for assessing the robustness and accuracy of radiomic textural features under various MR acquisition/reconstruction scenarios.
For the purpose of electrochemical applications (such as Ni-Zn batteries), we have experimentally studied the electrical impedimetric response of electrochemical systems (ECSs), in which the anodes ...were fabricated from nano-sized ZnO material doped with high-temperature superconducting ceramics Bi1.7Pb0.3Sr2CaCu2Oy (B(Pb)SCCO 2212) at concentration of either 5, 7, or 10 wt%. The electro-conducting properties of such ECSs with alkaline electrolyte were characterized at ambient temperature by measurements with electrochemical impedance spectroscopy in the frequency range 0.1 Hz –100 kHz. The effect from the ceramics additives on both complex electrical impedance and electrical conductivity of the examined ECSs was estimated.
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