Toward better regulation of private pension funds

The author analyzes the typical model for regulating investments in private pension funds. Pension reforms like those pioneered by Chile are being initiated or considered in Argentina, Bolivia, China, Colombia, Costa Rica, Hungary, Mexico, Peru, Uruguay, and elsewhere. Such reforms greatly improve fiscal discipline, make social security benefits and burdens equitable, and deepen financial markets. But they are also typically accompanied by: tight restrictions on the investments in pension fund portfolios; restrictions on the management of mandated retirement savings (to newly created legal entities called pension administrators, to the exclusion of such financial intermediaries as banks and mutual funds); minimum-return guarantees from the state and/or pension funds; and commissions based on salary rather than on the volume of assets managed. Illustrating his conclusions with case studies from Chile and Peru, the author shows that these restrictions, though well-meant, are poorly justified by financial theory, distort incentives for competition based on product choice and efficiency, increase administrative costs, and seriously reduce the affiliates'appropriate risk-return choices and returns. And the resulting potential losses in retirement income are great. The author recommends a significant departure from the Chilean-style model of a private pension fund system. He briefly describes implementation and transition issues for the alternative system that he proposes, which would: permit diverse intermediaries -including banks and mutual funds that meet appropriate prudential standards- to manage retirement savings; allow a greater choice between investment products; require that returns be reported on a net basis; and charge commissions as a fraction of assets managed.Payment Systems&Infrastructure,Economic Theory&Research,International Terrorism&Counterterrorism,Environmental Economics&Policies,Insurance&Risk Mitigation,Pensions&Retirement Systems,Environmental Economics&Policies,Insurance&Risk Mitigation,Banks&Banking Reform,Economic Theory&Research

Photovoltage Bleaching in Bulk Heterojunction Solar Cells through Occupation of the Charge Transfer State

We observe a strong peak in the capacitive photocurrent of a MDMO-PPV / PCBM bulk heterojunction solar cell for excitation below the absorbance threshold energy. Illumination at the peak energy blocks charge capture at other wavelengths, and causes the photovoltage to drop dramatically. These results suggest that the new peak is due to a charge transfer state, which provides a pathway for charge separation and photocurrent generation in the solar cell.Comment: submitted to Physical Review Letter

Exciton generation and dissociation mechanisms in organic bulk heterojunction solar cell materials.

Characterization of the optical and electrical properties of organic solar cell materials is of prime importance to organic solar cell design. This thesis describes the use of capacitive photocurrent measurements to study the exciton generation and dissociation mechanisms of organic solar cell materials. The emphasis is on the study of the methanofullerene derivatives (e.g., PCBM) which act as the electron acceptor material. This is because much work has already been done studying electron donating polymers used in organic solar cells (in an effort to enhance their absorbance coefficient), but less information is available on the acceptor material. In the blend films of MDMO-PPV: PCBM, the charge generation rate in PCBM was discovered to be much higher than would be expected from the absorbance cross-section. This observation led to design of a photovoltage bleaching experiment to examine the charge generation mechanism. Here the effect of illumination by a tunable light source on the open circuit photovoltage of a MDMO-PPV: PCBM bulk heterojunction solar cell was measured. Illumination of light at the PCBM ground state singlet exciton causes a sharp decrease in the photovoltage, while illumination at the ground state MDMO-PPV exciton shows no change. A direct pathway of recombination of above gap generated charge carriers was identified. Photovoltage bleaching results suggests that excitation at the PCBM ground singlet state exciton increases the recombination rate of higher energy excitations, either by acting as a recombination center or by forcing higher energy carriers into short lived states that recombine before reaching the contacts. The fact that the photovoltage bleaching correlates with the ground state PCBM singlet exciton suggests that charge dissociation from PCBM preferentially generates long-lived localized states. Capacitive photocurrent measurements were then performed on isolated methanofullerene derivatives, with the polymer donor material absent. Several low energy transitions were resolved in the optical spectroscopy of methanofullerene derivatives. These low energy states lay below the optical energy band-gap of these materials, so that their presence was unexpected. It was determined that the low energy states overlapped with the plasmon state of the highly conducting substrates (Indium Tin Oxide) which were in close proximity with the PCBM. Plasmon states in ITO have been observed previously, but the results presented in this thesis are unique in that this is the first evidence of charge transfer from the plasmon state of ITO to a high electron affinity fullerene derivative. The results show the evidence of charge transfer from PCBM to ITO over a broad wavelength range of 400 - 2400 nm (3 eV - 0.5 eV). Few materials have been observed to have absorbance and charge transfer over such a large range of energies in the infra-red regime. These results open a new direction for development of organic solar cell design with higher power conversion efficiencies

Dispersion of narrow diameter carbon nanotubes for optical characterization.

Optical properties of carbon nanotubes have recently attracted considerable amount of attention. Due to there direct band gap material characteristic these and dimension of the order of nano meters they find potential applications in the field of nano photonics. Thus the optical study of carbon nanotubes is important for both fundamental research and for the next generation technical applications. In this thesis single walled carbon nanotubes were dispersed in various encapsulates such as surfactants, polymers, proteins etc to separate them individually and study there optical properties. The individually dispersed single walled carbon nanotubes displayed unique absorbance spectra. The optical absorption spectrum of a particular tube is expected to be dominated by a series of relatively sharp inter-band transitions, at energies associated with the van Hove singularities, the absorbance spectrum obtained on our samples were consistent with this expectation. Our samples also showed sharp photoluminescence peaks mostly from the semiconducting single walled carbon nanotubes. The detailed overlap of the absorbance spectra and photoluminescence spectra lead us to believe that our samples contain mainly individual tubes encapsulated in one of the surfactants or polymers. Thin film transistors (TFT) were made with a mesh of single walled carbon nanotubes as the active channel on top of a silicon/silicon oxide substrate, with silicon acting as a back gate and titanium/gold electrodes were evaporated on top of the nanotube film. Photocurrent properties of these thin films were investigated and they showed a huge change in the photocurrent in the presence and absence of the laser light. Thin films of carbon nanotubes were also deposited on rectangular silicon substrates and the influence of applied strain in the presence of laser light was investigated. These films showed a huge change in resistance on application of mechanical strain. Raman measurements were also performed on these thin films and the obtained radial breathing mode (RBM) data helped resolve the diameter of many single walled carbon nanotubes

Analysing the Masked predictive coding training criterion for pre-training a Speech Representation Model

Recent developments in pre-trained speech representation utilizing self-supervised learning (SSL) have yielded exceptional results on a variety of downstream tasks. One such technique, known as masked predictive coding (MPC), has been employed by some of the most high-performing models. In this study, we investigate the impact of MPC loss on the type of information learnt at various layers in the HuBERT model, using nine probing tasks. Our findings indicate that the amount of content information learned at various layers of the HuBERT model has a positive correlation to the MPC loss. Additionally, it is also observed that any speaker-related information learned at intermediate layers of the model, is an indirect consequence of the learning process, and therefore cannot be controlled using the MPC loss. These findings may serve as inspiration for further research in the speech community, specifically in the development of new pre-training tasks or the exploration of new pre-training criterion's that directly preserves both speaker and content information at various layers of a learnt model

Anaesthetic concerns of difficult airway in case of large oral hemangioma posted for robotic cystectomy

A difficult airway poses a challenge to attending anaesthesiologist. Fibreoptic intubation (FOI) to secure airway can be a valuable option in such a scenario. Steep Trendelenberg’s position with pneumoperitoneum in robotic surgery causes respiratory changes with airway oedema and congestion. We are describing here a case report of 56-year male patient with a large congenital oral cavity hemangioma with primary urothelial neoplasm of bladder posted for robotic radical cystectomy with ileal conduit with urethrectomy. We emphasize the importance of difficult airway management by using fibre optic technique in such cases complicated by steep Trendelenburg’s position required during robotic surgeries

Anaesthesia considerations in a case of Morquio syndrome with bilateral mechanical vertebral artery occlusion: a case report

Morquio syndrome (MS) or mucopolysaccharidosis (MPS) type IVA is a progressive lysosomal storage disorder with autosomal recessive inheritance. Deficiency of enzymes N-acetyl-galactosamine-6-sulphatase and beta-galactosidase which compromises the catabolism of the glycosaminoglycans (GAGs) leads to excessive accumulation of GAGs in soft tissue, cartilage and bone causing severe skeletal dysplasia and difficult airway. Other systems commonly involved systems are cardiovascular, respiratory, neurological, ophthalmological, otolaryngological and hepatosplenic. Most of the patients with MPS survive up to second or third decade only. We present a case of 7 years old male child, known case of Morquio syndrome who presented with acute cerebral arterial stroke due to bilateral mechanical vascular occlusion of vertebral artery, posted for occipito-cervical fusion. Understanding Morquio syndrome, its airway and the anesthetic implications and careful planning of the anesthetic technique enabled us to manage this patient successfully

The relationship between emotional intelligence and academic achievement in medical undergraduate

Background: In today’s era of technology, intelligence and success are not viewed the same way they were before. New theories of intelligence have been introduced and are gradually replacing the traditional theory. Academic achievement is based on creativity, emotions, and interpersonal skills. Methods: The aim of this study was to see whether there is a relationship between emotional intelligence and academic success. Study was done on 1st MBBS students of Govt. Medical College, Bhavnagar. The sample size was 75 students (boys and girls). The emotional intelligence questionnaire from Institute for Health and Human Potential was given to the students, Depending on the EQ score we divided the students in to five groups and compared with their academic performance. Results: Study showed inverse relationship between emotional intelligence and academic achievement.Conclusion: There is a negative relation among emotional intelligence and academic achievement of the participants