Determination of Weak Amplitudes using Bose Symmetry and Dalitz Plots

We present a new method using Dalitz plot and Bose symmetry of pions that allows the complete determination of the magnitudes and phases of weak decay amplitudes. We apply the method to process like B->K^* pi, with the subsequent decay of K^* -> K pi. Our approach enables the additional measurement of an isospin amplitude without any theoretical assumption. This advance will help in measuring weak phase and probing for new physics beyond standard model with fewer assumptions.Comment: 5 pages, 1 figure; Title changed; Conclusions unchanged; Accepted for publication in Physical Review Letter

Post hepatectomy liver failure (PHLF) – Recent advances in prevention and clinical management

Under embargo until: 2021-09-10Background Posthepatectomy liver failure (PHLF) is a relatively rare but feared complication following liver surgery, and associated with high morbidity, mortality and cost implications. Significant advances have been made in detailed preoperative assessment, particularly of the liver function in an attempt to predict and mitigate this complication. Methods A detailed search of PubMed and Medline was performed using keywords “liver failure”, “liver insufficiency”, “liver resection”, “postoperative”, and “post-hepatectomy”. Only full texts published in English were considered. Particular emphasis was placed on literature published after 2015. A formal systematic review was not found feasible hence a pragmatic review was performed. Results The reported incidence of PHLF varies widely in reported literature due to a historical absence of a universal definition. Incorporation of the now accepted definition and grading of PHLF would suggest the incidence to be between 8 and 12%. Major risk factors include background liver disease, extent of resection and intraoperative course. The vast majority of mortality associated with PHLF is related to sepsis, organ failure and cerebral events. Despite multiple attempts, there has been little progress in the definitive and specific management of liver failure. This review article discusses recent advances made in detailed preoperative evaluation of liver function and evidence-based targeted approach to managing PHLF. Conclusion PHLF remains a major cause of mortality following liver resection. In absence of a specific remedy, the best approach is mitigating the risk of it happening by detailed assessment of liver function, patient selection and general care of a critically ill patient.acceptedVersio

Weak Phase gamma Using Isospin Analysis and Time Dependent Asymmetry in B_d -> K_s pi^+ pi^-

We present a method for measuring the weak phase gamma using isospin analysis of three body B decays into K pi pi channels. Differential decay widths and time dependent asymmetry in B_d -> K_s pi^+pi^- mode needs to be measured into even isospin pi pi states. The method can be used to extract gamma, as well as, the size of the electroweak penguin contributions. The technique is free from assumptions like SU(3) or neglect of any contributions to the decay amplitudes. By studying different regions of the Dalitz plot, it is possible to reduce the ambiguity in the value of gamma.Comment: 11 pages, 1 figur

Adding the Third Dimension to Building Construction Technology in Architecture Education

This paper looks into conventional teaching practices and intends to generate a new approach towards the teaching of Building Construction in architecture schools. With the fast pace of the current world and changing technology, conventional teaching practices that are largely based on information assimilation have ceased to serve us adequately. The rate of change in trends and technologies in the current times do not match the content of our existing syllabus. This paper tries to identify the role and application of Building Construction Technology for training the young minds for handling future challenges and coping up with upcoming developments. It talks about various experimentation and exploration techniques aimed at enhancing the student’s analytical ability as well as his/her understanding of materials, techniques, systems, etc. The Building Construction Technology team at IDEAS has tried to bridge the gap between conventional teaching methods and the changing technology by adding a third dimension to reaching-learning methodology. The paper presents methods devised and tested in the Second Year Building Construction Studio for enabling the students for creative handling of materials and technology

Improving Outcomes with Surgical Resection and Other Ablative Therapies in HCC

With rising incidence and emergence of effective treatment options, the management of hepatocellular carcinoma (HCC) is a complex multidisciplinary process. There is still little consensus and uniformity about clinicopathological staging systems. Resection and liver transplantation have been the cornerstone of curative surgical treatments with recent emergence of ablative techniques. Improvements in diagnostics, surgical techniques, and postoperative care have lead to dramatically improved results over the years. The most appropriate treatment plan has to be individualised and depends on a variety of patient and tumour-related factors. Very small HCCs discovered on surveillance have the best outcomes. Patients with advanced cirrhosis and tumours within Milan criteria should be offered transplantation. Resection is best for small solitary tumours with preserved liver function. Ablative techniques are suitable for low volume tumours in patients unfit for either resection or transplantation. The role of downstaging and bridging therapy is not clearly established

Nuclear Spin Dynamics Under Above-Bandgap Optical Pumping in Silicon

Phosphorus defects in silicon have been proposed as candidates for quantum information and quantum sensing applications, with proposals utilizing both the donor electron spin as well as the 31P nuclear spin. Initialization of the nuclear spin in its ground state (hyperpolarization) is essential for these applications. Silicon also has a spin-1/2 isotope (29Si) with 4.7% abundance. 29Si nuclear spins have long spin-lattice relaxation times compared to experimental timescales, providing a thermally isolated system whose effective temperature (polarization) can be controlled. This can serve as a test-bed for studying central spin effects and other many-body experiments. However, spin-spin interactions are relatively weak, requiring lower spin temperatures (hyperpolarization) than have been previously achieved in bulk silicon in order to see collective effects. Optical pumping with above-bandgap light (1047 nm) has been shown to drive hyperpolarization processes on the 31P as well as 29Si nuclear spins in lightly doped silicon (∼10^15 cm^−3). There are various proposals for the mechanisms driving these processes, some conflicting, with very little experimental confirmation. In the first part of this thesis, we demonstrate that the 31P nuclear spin hyperpolarization in isotopically enriched 28Si is generated by a phononic cross-relaxation process, which is accelerated and driven by the optical pumping to a different effective temperature compared to the electron spin relaxation (T1) process. We propose an experiment to hyperpolarize the 31P nuclear spins faster using AC electric fields. In addition to identifying the hyperpolarization process, we use the change in the resonance frequency of the 31P nuclear spin under an Auger recombination driven ionization process to measure the rates of ionization and photoneutralization of the defect site in the presence of above-bandgap light. The method is an example of NMR under chemical exchange. We find a paramagnetic shift on 31P nuclear spins in the ionized defect (D+) state, which has not been reported previously. In the second half of the thesis, we investigate the polarization buildup of 31P and 29Si nuclear spins in natural abundance silicon. We demonstrate that the 29Si polarization originates from the 31P defect sites, in a many-body effect where nearby (core) 29Si are polarized by a cross-relaxation process similar to that driving the 31P polarization, followed by spin diffusion to the rest (bulk) of the 29Si spins. We also experimentally confirm the existence of a 31P-29Si resonant matching field condition at 6.7 T, where the heteronuclear dipole-dipole interaction is able to exchange polarization efficiently in the excited state manifold of the electron spin, and demonstrate its dependence on the laser power as well as its effect on the 31P nuclear spin polarization. We model the system using quantum simulations on small model spin systems, as well as with simplified rate equations, and show that the rate-limiting step is the buildup of polarization of the nearby (core) 29Si spins. We use our knowledge of the defect ionization rates to establish a lower bound on the spin diffusion rate across the diffusion barrier at the defect site and verify that the data is consistent with these lower bounds. The insights provided by our results suggest future experiments to create highly polarized 29Si ensembles. This might serve as a test-bed for central spin effects and other many-body experiments