A Study of Bhabha Scattering at the Z Resonance

In this thesis, I present a study on Bhabha scattering at the Z resonance using the 13 detector at 1EP. I have measured the cross section and forward-backward asymmetry measurement for the process e⁺e⁻ → e⁺e⁻(nγ) in the large angle region ( 44° &#60; θe⁺e⁻ &#60; 136°). The data used was collected during 1993 (3 energy points at the Z resonance) and 1994 (Peak point only), corresponding to a total of 66,000 e⁺e⁻ pairs. The results of my measurement are combined with those from other 13 measurements of Z production and decays to provide a precision test of the Standard Model. Electroweak parameters are determined with unprecedented precision. The main results in this thesis are as follows: the cross section of e⁺e⁻ → e⁺e⁻(nγ) process at the Z peak: σ = 1.072 ± 0.005 (stat.) ± 0.002 (sys.) nb, the forward-backward asymmetry of e⁺e⁻ → e⁺e⁻(nγ) process at the peak: AFB = 0.122 ± 0.006 (stat.) ± 0.003 (sys.), the mass of the Z boson: Mz = 91188.3 ± 2.9 MeV, the total width of the Z boson: Γz = 2499.8 ± 4.3 MeV, the partial decay width of the Z boson into electrons: Γe = 83.99 ± 0.26 MeV, the Z electroweak coupling constants to fermions: -ℓ/gV, -ℓ/gA = -0.5010 ± 0.0006, the effective weak mixing angle: sin² θ̅ w = 0.2304 ± 0.0009, the mass of the top quark: Mt = 189+12-13 ± 17 GeV, the mass of the Higgs boson: MH = 91+230-81 GeV; MH &#60; 645 GeV 95% CL. All the results from different measurements yield consistent results. No indication of a deviation from the Standard Model has been observed.</p

Rethinking preventative detention from an international human rights perspective: a comparative study of Australia, Malaysia and Singapore

In order to prevent terrorist attacks, in 2005 Australia introduced a new division into the Criminal Code 1995 (Cth). This allows preventative detention of terrorism suspects who have not been charged with any offence and of even non-suspects, for up to 48 hours under federal law, with the possibility of extending the detention up to 14 days under complementary State and Territory legislation. In contrast, since September 11, both Malaysia and Singapore have adopted only minor changes to their existing anti-terrorism laws. The two states have long dealt with terrorism suspects by relying primarily on the detention without charge measures provided for under the Internal Security Act 1960 (Malaysia) and the Internal Security Act 1965 (Singapore). The two Acts give the executive sweeping powers, including the power to indefinitely detain persons without charge for the purpose of national security. This thesis examines and compares the preventative detention measures adopted by these three states from an international human rights perspective. Security-based preventative detention is a permissible deprivation of liberty under the International Covenant on Civil and Political Rights as long as it is lawful and proportionate, but any detention without charge must conform to the procedural constraints. Despite the fact that Australia's detention regime includes some safeguards, its provisions are highly problematic. In Malaysia and Singapore, both schemes have been consistently used to suppress political dissidents rather than to protect the state from threats of terrorist acts. Although Australia's new detention regime has a different maximum period of detention and grounds of detention, it has in common with its Malaysian and Singaporean counterparts a lack of sufficient and effective procedural safeguards. These include the absence of a detainee's rights to a substantive merits review of the detention grounds, to have regular contact with the outside world, and to have confidential lawyer-client communications. The thesis concludes that the normalisation of extraordinary emergency rules in Malaysia and Singapore is already against international human rights law, and there is a real danger that Australia’s preventative detention regime might damage the established rule of law and the criminal justice system

Insights from Niche Markets: Explainable and Predictive Values of Consumption Tendency on Credit Risks

The rapid development of FinTech drives the growing popularity of digital payment transactions. This phenomenon, especially given the increasing number of offline and online transactions being recorded in a real-time manner, offers great opportunities for financial service platforms to track consumers’ consumption tendencies and dynamically monitor and evaluate their creditworthiness. In our recent research, we first theorized the value of category-level consumption tendency based on the self-regulatory theory and employed econometric methods to empirically test the relationship between category-level consumption tendency and credit behavior. Then, we proposed a Deep Hierarchical Partial Attention-based Model (DHPAM) to predict credit default risk with full employment of product category features. We provided strong experimental evidence to show that the proposed DHPAM outperforms the state-of-the-art machine learning models. This paper, based on theories, empirical analyses, and a prediction model, offers comprehensive and practical guidance on the optimal utilization of consumption information in credit risk management

Analysis of Demographic Characteristics and Psychological Factors of Opioid Addicts in Zhengzhou Area

Objective: To explore the demographic characteristics and psychological factors of patients with opioid addiction. Methods: A random number method was used to select 200 opioid-addicted patients admitted to the 7th People’s Hospital of Zhengzhou from January 2019 to February 2020. Demographic characteristics and psychosocial factors were analyzed. Result: The proportion of opioid addicts aged 21 ~ 30 was the highest; the proportion of men was significantly higher; the proportion of people who is between jobs/unemployed is the highest; the proportion of junior middle school was the highest, and the proportion of unmarried was relatively high; the proportion of opioid addicts with ignorance/curiosity for the cause of first addiction was the highest; the use of suction is snorting, accounting for the highest proportion. According to the analysis of relevant social and psychological factors, the proportion of single parent family group is the highest, the proportion of parent tension is the highest, and the proportion of bad life coping style is relatively high. At the same time, dependent psychology occupies the highest proportion in psychological factors of relapse patients. Conclusion: By analyzing the demographic characteristics of opioid addicts and the psychosocial factors of their addiction, we can strengthen prevention and management for specific groups to reduce the new addition and relapse of opioid addicts

Challenges of refractive cataract surgery in the era of myopia epidemic: a mini-review

Myopia is the leading cause of visual impairment in the world. With ever-increasing prevalence in these years, it creates an alarming global epidemic. In addition to the difficulty in seeing distant objects, myopia also increases the risk of cataract and advances its onset, greatly affecting the productivity of myopes of working age. Cataract management in myopic eyes, especially highly myopic eyes is originally more complicated than that in normal eyes, whereas the growing population of cataract with myopia, increasing popularity of corneal and lens based refractive surgery, and rising demand for spectacle independence after cataract surgery all further pose unprecedented challenges to ophthalmologists. Previous history of corneal refractive surgery and existence of implantable collamer lens will both affect the accuracy of biometry including measurement of corneal curvature and axial length before cataract surgery, which may result in larger intraocular lens (IOL) power prediction errors and a compromise in the surgical outcome especially in a refractive cataract surgery. A prudent choice of formula for cataract patients with different characteristics is essential in improving this condition. Besides, the characteristics of myopic eyes might affect the long-term stability of IOL, which is important for the maintenance of visual outcomes especially after the implantation of premium IOLs, thus a proper selection of IOL accordingly is crucial. In this mini-review, we provide an overview of the impact of myopia epidemic on treatment for cataract and to discuss new challenges that surgeons may encounter in the foreseeable future when planning refractive cataract surgery for myopic patients

Unshifted Metastable He I* Mini-Broad Absorption Line System in the Narrow Line Type 1 Quasar SDSS J080248.18++551328.9

We report the identification of an unusual absorption line system in the quasar SDSS J080248.18$+$551328.9 and present a detailed study of the system, incorporating follow-up optical and NIR spectroscopy. A few tens of absorption lines are detected, including He I*, Fe II* and Ni II* that arise from metastable or excited levels, as well as resonant lines in Mg I, Mg II, Fe II, Mn II, and Ca II. All of the isolated absorption lines show the same profile of width $\Delta v\sim 1,500$km s$^{-1}$ centered at a common redshift as that of the quasar emission lines, such as [O II], [S II], and hydrogen Paschen and Balmer series. With narrow Balmer lines, strong optical Fe II multiplets, and weak [O III] doublets, its emission line spectrum is typical for that of a narrow-line Seyfert 1 galaxy (NLS1). We have derived reliable measurements of the gas-phase column densities of the absorbing ions/levels. Photoionization modeling indicates that the absorber has a density of $n_{\rm H} \sim (1.0-2.5)\times 10^5~ {\rm cm}^{-3}$ and a column density of $N_{\rm H} \sim (1.0-3.2)\times 10^{21} \sim {\rm cm}^{-2}$, and is located at $R\sim100-250$ pc from the central super-massive black hole. The location of the absorber, the symmetric profile of the absorption lines, and the coincidence of the absorption and emission line centroid jointly suggest that the absorption gas is originated from the host galaxy and is plausibly accelerated by stellar processes, such as stellar winds \zhy{and/or} supernova explosions. The implications for the detection of such a peculiar absorption line system in an NLS1 are discussed in the context of co-evolution between super-massive black hole growth and host galaxy build-up.Comment: 28 pages, 16 figures; accepted for publication in Astrophysical Journa