Studies on Polinial Apparatus & Carriers of Asclepiadaceae sensu Lato

The agglutination pollen to form waxy pollinia is a rare event and is seen in the families, namely Asclepiadaceae and Orchidaceae. Terminology for the pollinia structures used has been analytically viewed. In Asclepiadaceae, the pollinial - apparatus are morphologically significant and varied. The characters of pollen - carriers and pollinial - apparatus are being used in classification of various taxa. Certain important characters of pollinial - apparatus and pollen - carriers are being considered in the text are very much valuable and they form key role in identifying species and genera. Additionally, the sites of germination of pollinia are important and distinct in different tribes of Asclepiadaceae and they are aptly placed on the stigmatic receptive surface by the highly evolved sophisticated method of insect pollination. Based on these, an evolutionary tree has been presented for the Asclepiadaceae sensu lato

Analysis of Various Polarization Asymmetries In The Inclusive b→sℓ+ℓ−b\to s \ell^+ \ell^- Decay In The Fourth-Generation Standard Model

In this study a systematical analysis of various polarization asymmetries in inclusive b \rar s \ell^+ \ell^- decay in the standard model (SM) with four generation of quarks is carried out. We found that the various asymmetries are sensitive to the new mixing and quark masses for both of the $\mu$ and $\tau$ channels. Sizeable deviations from the SM values are obtained. Hence, b \rar s \ell^+ \ell^- decay is a valuable tool for searching physics beyond the SM, especially in the indirect searches for the fourth-generation of quarks ($t', b')$.Comment: 19 Pages, 10 Figures, 3 Table

b -> s gamma in the left-right supersymmetric model

The rare decay $b \to s \gamma$ is studied in the left-right supersymmetric model. We give explicit expressions for all the amplitudes associated with the supersymmetric contributions coming from gluinos, charginos and neutralinos in the model to one-loop level. The branching ratio is enhanced significantly compared to the standard model and minimal supersymmetric standard model values by contributions from the right-handed gaugino and squark sector. We give numerical results coming from the leading order contributions. If the only source of flavor violation comes from the CKM matrix, we constrain the scalar fermion-gaugino sector. If intergenerational mixings are allowed in the squark mass matrix, we constrain such supersymmetric sources of flavor violation. The decay $b \to s \gamma$ sets constraints on the parameters of the model and provides distinguishing signs from other supersymmetric scenarios.Comment: 12 figure

Supersymmetric effects on Forward Backward asymmetries of B→Kℓ+ℓ−B \to K \ell^+ \ell^-

Leptonic and semi-leptonic rare decays of B-mesons are very clean (both theoretically and experimentally) signatures of any new physics beyond the Standard Model (SM). More specifically the decay \btokll has been theoretically observed to be very sensitive to new physics as the Forward Backward (FB) asymmetry in this decay mode vanishes in the SM. Supersymmetry, however, predicts a non-vanishing value of this asymmetry. In this work we will study the polarized lepton pair FB asymmetry, i.e. the FB asymmetry of the lepton when one (or both) final state lepton(s) are polarized. We will study these asymmetries both within the SM and for Supersymmetric corrections to the SM.Comment: 18 pages, RevTeX file including 21 eps figures; version accepted for publication in Phys. Rev. D. Some references adde

CP violation in Bd,s→l+l−B_{d,s} \to l^+l^- in the model III 2HDM

We have calculated the Wilson coefficients $C_{10}, C_{Q_i}$ (i=1,2) in the $\bar{MS}$ renormalization scheme in the model III 2HDM. Using the obtained Wilson coefficients, we have analyzed the CP violation in decays $B^0_q\to l^+l^-$ (q=d,s) in the model. The CP asymmetry, $A_{CP}$, depends on the parameters of models and $A_{CP}$ in $B_d\to l^+l^-$ can be as large as 40% and 35% for $l=\tau$ and $l=\mu$ respectively. It can reach 4% for $B^0_s$ decays. Because in SM CP violation is smaller than or equal to O($10^{-3}$) which is unobservably small, an observation of CP asymmetry in the decays $B^0_q \to l^+l^- (q=d,s)$ would unambiguously signal the existence of new physics.Comment: revtex4, 16 pages, 7 figure

Many-body aspects of positron annihilation in the electron gas

We investigate positron annihilation in electron liquid as a case study for many-body theory, in particular the optimized Fermi Hypernetted Chain (FHNC-EL) method. We examine several approximation schemes and show that one has to go up to the most sophisticated implementation of the theory available at the moment in order to get annihilation rates that agree reasonably well with experimental data. Even though there is basically just one number to look at, the electron-positron pair distribution function at zero distance, it is exactly this number that dictates how the full pair distribution behaves: In most cases, it falls off monotonously towards unity as the distance increases. Cases where the electron-positron pair distribution exhibits a dip are precursors to the formation of bound electron--positron pairs. The formation of electron-positron pairs is indicated by a divergence of the FHNC-EL equations, from this we can estimate the density regime where positrons must be localized. This occurs in our calculations in the range 9.4 <= r_s <=10, where r_s is the dimensionless density parameter of the electron liquid.Comment: To appear in Phys. Rev. B (2003

More Model-Independent Analysis of b->s Processes

We study model-independently the implications of non-standard scalar and pseudoscalar interactions for the decays b ->s gamma, b -> s g, b -> s l^+l^- (l=e,mu) and B_s -> mu^+ mu^-. We find sizeable renormalization effects from scalar and pseudoscalar four-quark operators in the radiative decays and at O(alpha_s) in hadronic b decays. Constraints on the Wilson coefficients of an extended operator basis are worked out. Further, the ratios R_H = BR(B -> H mu^+ mu^-)/BR(B -> H e^+ e^-), for H=K^(*), X_s, and their correlations with B_s -> mu^+ mu^- decay are investigated. We show that the Standard Model prediction for these ratios defined with the same cut on the dilepton mass for electron and muon modes, R_H= 1 + O(m^2_mu/m^2_b), has a much smaller theoretical uncertainty (<1%) than the one for the individual branching fractions. The present experimental limit R_K < 1.2 puts constraints on scalar and pseudoscalar couplings, which are similar to the ones from current data on BR(B_s -> mu^+ mu^-). We find that new physics corrections to R_{K*} and R_{X_s} can reach 13% and 10%, respectively.Comment: 28 pages, 6 figures; Table 1 updated, two refs added (to appear in PRD

The Forward-Backward Asymmetry of B to (pi,K) l^+ l^-: Supersymmetry at Work

We analyze the forward-backward asymmetry of the decays B to (pi,K) l^+ l^- with l = mu or tau in the framework of the constrained minimal supersymmetric standard model. We find that, the asymmetry is enhanced at large tan beta and depends strongly on the sign of the mu parameter. For mu > 0, the asymmetry is typically large and observable whereas for mu < 0, it changes the sign and is suppressed by an order of magnitude. Including cosmological constraints we find that the asymmetry has a maximal value of about 30 %, produced when Higgs- and gauge- induced flavor violations are of comparable size, at a value of tan beta simeq 35. The present constraints from the B-factories are too weak to constrain parameter space, and the regions excluded by them are already disfavoured by at least one of B to X_s gamma, g-2, and/or cosmology. The size of the asymmetry is mainly determined by the flavor of the final state lepton rather than the flavor of the pseudoscalar.Comment: 18 pages; 11 eps figures; minor changes in text; journal versio

Clinical and Demographic Factors Associated with COVID-19, Severe COVID-19, and SARS-CoV-2 Infection in Adults: A Secondary Cross-Protocol Analysis of 4 Randomized Clinical Trials

Importance: Current data identifying COVID-19 risk factors lack standardized outcomes and insufficiently control for confounders. Objective: To identify risk factors associated with COVID-19, severe COVID-19, and SARS-CoV-2 infection. Design, Setting, and Participants: This secondary cross-protocol analysis included 4 multicenter, international, randomized, blinded, placebo-controlled, COVID-19 vaccine efficacy trials with harmonized protocols established by the COVID-19 Prevention Network. Individual-level data from participants randomized to receive placebo within each trial were combined and analyzed. Enrollment began July 2020 and the last data cutoff was in July 2021. Participants included adults in stable health, at risk for SARS-CoV-2, and assigned to the placebo group within each vaccine trial. Data were analyzed from April 2022 to February 2023. Exposures: Comorbid conditions, demographic factors, and SARS-CoV-2 exposure risk at the time of enrollment. Main Outcomes and Measures: Coprimary outcomes were COVID-19 and severe COVID-19. Multivariate Cox proportional regression models estimated adjusted hazard ratios (aHRs) and 95% CIs for baseline covariates, accounting for trial, region, and calendar time. Secondary outcomes included severe COVID-19 among people with COVID-19, subclinical SARS-CoV-2 infection, and SARS-CoV-2 infection. Results: A total of 57692 participants (median [range] age, 51 [18-95] years; 11720 participants [20.3%] aged ≥65 years; 31058 participants [53.8%] assigned male at birth) were included. The analysis population included 3270 American Indian or Alaska Native participants (5.7%), 7849 Black or African American participants (13.6%), 17678 Hispanic or Latino participants (30.6%), and 40745 White participants (70.6%). Annualized incidence was 13.9% (95% CI, 13.3%-14.4%) for COVID-19 and 2.0% (95% CI, 1.8%-2.2%) for severe COVID-19. Factors associated with increased rates of COVID-19 included workplace exposure (high vs low: aHR, 1.35 [95% CI, 1.16-1.58]; medium vs low: aHR, 1.41 [95% CI, 1.21-1.65]; P <.001) and living condition risk (very high vs low risk: aHR, 1.41 [95% CI, 1.21-1.66]; medium vs low risk: aHR, 1.19 [95% CI, 1.08-1.32]; P <.001). Factors associated with decreased rates of COVID-19 included previous SARS-CoV-2 infection (aHR, 0.13 [95% CI, 0.09-0.19]; P <.001), age 65 years or older (aHR vs age <65 years, 0.57 [95% CI, 0.50-0.64]; P <.001) and Black or African American race (aHR vs White race, 0.78 [95% CI, 0.67-0.91]; P =.002). Factors associated with increased rates of severe COVID-19 included race (American Indian or Alaska Native vs White: aHR, 2.61 [95% CI, 1.85-3.69]; multiracial vs White: aHR, 2.19 [95% CI, 1.50-3.20]; P <.001), diabetes (aHR, 1.54 [95% CI, 1.14-2.08]; P =.005) and at least 2 comorbidities (aHR vs none, 1.39 [95% CI, 1.09-1.76]; P =.008). In analyses restricted to participants who contracted COVID-19, increased severe COVID-19 rates were associated with age 65 years or older (aHR vs <65 years, 1.75 [95% CI, 1.32-2.31]; P <.001), race (American Indian or Alaska Native vs White: aHR, 1.98 [95% CI, 1.38-2.83]; Black or African American vs White: aHR, 1.49 [95% CI, 1.03-2.14]; multiracial: aHR, 1.81 [95% CI, 1.21-2.69]; overall P =.001), body mass index (aHR per 1-unit increase, 1.03 [95% CI, 1.01-1.04]; P =.001), and diabetes (aHR, 1.85 [95% CI, 1.37-2.49]; P <.001). Previous SARS-CoV-2 infection was associated with decreased severe COVID-19 rates (aHR, 0.04 [95% CI, 0.01-0.14]; P <.001). Conclusions and Relevance: In this secondary cross-protocol analysis of 4 randomized clinical trials, exposure and demographic factors had the strongest associations with outcomes; results could inform mitigation strategies for SARS-CoV-2 and viruses with comparable epidemiological characteristics

Track D Social Science, Human Rights and Political Science

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138414/1/jia218442.pd