Portfolio diversification utilising rolling economic drawdown constraints and risk factor analysis

This study investigates a new asset allocation technique termed Factor Adjusted Rolling Economic Drawdown (FAREDD), whereby resources are allocated to different assets by way of integrating Principle Component Analysis (PCA) with existing Rolling Economic Drawdown Methods (REDD). The primary purpose of this model is to create a portfolio with low drawdown levels, that can withstand turbulent market periods thus protecting portfolio value through providing stronger diversification benefits while still seeking to maximise risk adjusted and overall return. This will have strong implications for investors as it could provide an additional method and tool to be considered during the asset allocation decision stage if they have a strong drawdown aversion. The concept of FAREDD is developed in this study within a South African context and compares this method with several traditional allocation methods including mean-variance optimised models, risk parity as well as traditional rolling economic drawdown models. So far, at the point of writing this study, the author has been unable to find any previous studies documenting this type of application of PCA to REDD. In addition to this, all previous studies that has investigated rolling economic drawdown has been conducted exclusively on the United States of America. The literature finds that REDD provides a viable and superior alternative to traditional asset allocation in the long run. Thus, as part of this study, a second objective is to investigate whether REDD models provide sufficient protection and superior returns in a developing economy with a significantly lower number of available liquid assets and higher volatility due to increased political, economic and business risk, when compared to alternative more traditional allocation techniques. The key findings of this study are that the FAREDD model does outperform the traditional REDD model that it is compared to for the period and it also meets the objective of providing low drawdowns and volatility while achieving strong risk-adjusted returns. However, the model does not provide the strongest drawdown protection of all portfolios tested. The FAREDD model is surpassed by the minimum-variance portfolio in this regard but from a risk adjusted basis and an overall return perspective it far outperforms the minimum-variance portfolio. Therefore, the performance of the FAREDD model is mixed and its optimality would need to be assessed relative to an investor’s risk appetite and risk-return trade-off. In addition to this, the paper finds that the performance of traditional REDD models in the South African context are mixed when compared to traditional asset allocation techniques thereby indicating that REDD models may not be superior in the South African market place at all times. However, they can provide relevant and potential asset allocation alternatives for mangers to consider

A tuberculosis contact investigation involving two private nursing homes in inner western Sydney in 2004

Australia has one of the lowest incidence rates of tuberculosis (TB) in the world, approximately five per 100,000 per year 1, although in some parts of the country the incidence is considerably higher. In the former Central Sydney Area Health Service the incidence rate in 2003 was 14 per 100,000 per year.2 The incidence is also higher in those aged 65 years and over1, a population that has declining immunocompetence due to a variety of factors.3 Furthermore, the subpopulation of this group (and, indeed, of people of any age) living in residential institutions such as nursing homes and hostels are at even greater risk of TB infection and disease due to their chronic ill health and multiple medical problems.3 Despite this, there are no guidelines in NSW regarding TB screening of the elderly, either in response to potential exposure or with regard to screening at entry to a residential facility. There are also very few reports in the literature of TB contact investigations in residential facilities. Those that have been published come from the United States and are concerned with TB in hospitals or correctional facilities.3,4,5,6 There has been one report of TB transmission in a school setting in Sydney7, but there is a paucity of Australian literature that clarifies what is required for contact investigations in the local residential care setting. This paper describes a contact investigation resulting from a case of active TB in a health care worker employed by a number of nursing homes in inner-western Sydney and highlights the need for policies with regard to TB screening of the elderly residing in nursing homes

Virtual Microscopy with Extended Depth of Field

In this paper, we describe a virtual microscope system, based on JPEG 2000, which utilizes extended depth of field (EDF) imaging. Through a series of observer trials we show that EDF imaging improves both the local image quality of individual fields of view (FOV) and the accuracy with which the FOVs can be mosaiced (stitched) together. In addition, we estimate the required bit rate to adequately render a set of histology and cytology specimens at a quality suitable for on-line learning and collaboration. We show that, using JPEG 2000, we can efficiently represent high-quality, high-resolution colour images of microscopic specimens with less than 1 bit per pixel

Developing Unique Engineering Solutions to Improve Patient Safety

Many efforts to improve healthcare safety have focused on redesigning processes of care or retraining clinicians. Far less attention has been focused on the use of new technologies to improve safety. We present the results of a unique collaboration between the VA National Center for Patient Safety (NCPS) and the Thayer School of Engineering at Dartmouth College. Each year, the NCPS identifies safety problems across the VA that could be addressed with newly-engineered devices. Teams of Thayer students and faculty participating in a senior design course evaluate and engineer a solution for one of the problems. Exemplar projects have targeted surgical sponge retention, nosocomial infections, surgical site localization, and remote monitoring of hospitalized patients undergoing diagnostic testing and procedures. The program has served as an avenue for engineering students and health care workers to solve problems together. The success of this academic-clinical partnership could be replicated in other settings

Evolution of Atmospheric O2 Through the Phanerozoic, Revisited

An oxygen-rich atmosphere is essential for complex animals. The early Earth had an anoxic atmosphere, and understanding the rise and maintenance of high O2 levels is critical for investigating what drove our own evolution and for assessing the likely habitability of exoplanets. A growing number of techniques aim to reproduce changes in O2 levels over the Phanerozoic Eon (the past 539 million years). We assess these methods and attempt to draw the reliable techniques together to form a consensus Phanerozoic O2 curve. We conclude that O2 probably made up around 5–10% of the atmosphere during the Cambrian and rose in pulses to ∼15–20% in the Devonian, reaching a further peak of greater than 25% in the Permo-Carboniferous before declining toward the present day. Evolutionary radiations in the Cambrian and Ordovician appear consistent with an oxygen driver, and the Devonian “Age of the Fishes” coincides with oxygen rising above 15% atm. ▪ An oxygen-rich atmosphere is essential for complex animals such as humans. ▪ We review the methods for reconstructing past variation in oxygen levels over the past 539 million years (the Phanerozoic Eon). ▪ We produce a consensus plot of the most likely evolution of atmospheric oxygen levels. ▪ Evolutionary radiations in the Cambrian, Ordovician, and Devonian periods may be linked to rises in oxygen concentration

Developing consensus on the principles and key actions for collaborative working between general practices and community pharmacies: a modified eDelphi study

OBJECTIVES: To develop consensus on the principles and key actions for collaborative working in practice between general practice, community pharmacy and patients and their carers. DESIGN: Three-round modified eDelphi study, starting from an established conceptual model of collaboration between general practitioners (GPs) and community pharmacists. SETTING: Community pharmacies and general practices in England, UK. PARTICIPANTS: A panel of 123 experts: 43% from a community pharmacy background; 36% from a GP background; 13% patients, carers or patient representatives and 8% from academic or commissioner backgrounds. Panellist numbers reduced by approximately 30% in rounds 2 and 3. PRIMARY AND SECONDARY OUTCOME MEASURES: Consensus between expert panellists, defined as at least 75% agreement. RESULTS: A high level of consensus (>80%) was achieved on all components of a model of collaboration composed of Fundamental Principles of Collaboration and Key Activities for Action, supported by a series of aspirational statements and suggested practical actions. The fundamental principles and key activities are appended by contextual points. The findings indicate that collaboration in practice involves team members other than just GPs and community pharmacists and recognises that patients often want to know how each professional team is involved in their care. This study also provides insights into how collaboration between general practice and community pharmacy settings appears to have shifted during the COVID-19 pandemic, especially through opportunities for virtual collaboration and communication that can transcend the need for close geographical proximity. CONCLUSION: A consensus-based model of collaboration between general practice teams, community pharmacy teams, and patients and their carers has been developed. It is practically focused, values the patient voice and incorporates general practice and community pharmacy team members. While developed in England, the model is likely to also have applicability to other countries with similar health systems that include general practices and community pharmacies

Riboflavin-Vancomycin Conjugate Enables Simultaneous Antibiotic Photo-Release and Photodynamic Killing against Resistant Gram-Positive Pathogens

Decades of antibiotic misuse have led to alarming levels of antimicrobial resistance, and the development of alternative diagnostic and therapeutic strategies to delineate and treat infections is a global priority. In particular, the nosocomial, multidrug-resistant "ESKAPE" pathogens such as Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus spp (VRE) urgently require alternative treatments. Here, we developed light-activated molecules based on the conjugation of the FDA-approved photosensitizer riboflavin to the Gram-positive specific ligand vancomycin to enable targeted antimicrobial photodynamic therapy. The riboflavin-vancomycin conjugate proved to be a potent and versatile antibacterial agent, enabling the rapid, light-mediated, killing of MRSA and VRE with no significant off-target effects. The attachment of riboflavin on vancomycin also led to an increase in antibiotic activity against S. aureus and VRE. Simultaneously, we evidenced for the first time that the flavin subunit undergoes an efficient photoinduced bond cleavage reaction to release vancomycin, thereby acting as a photoremovable protecting group with potential applications in drug delivery

Bose-Einstein condensation of finite number of confined particles

The partition function and specific heat of a system consisting of a finite number of bosons confined in an external potential are calculated in canonical ensemble. Using the grand partition function as the generating function of the partition function, an iterative scheme is established for the calculation of the partition function of system with an arbitrary number of particles. The scheme is applied to finite number of bosons confined in isotropic and anisotropic parabolic traps and in rigid boxes. The specific heat as a function of temperature is studied in detail for different number of particles, different degrees of anisotropy, and different spatial dimensions. The cusp in the specific heat is taken as an indication of Bose-Einstein condensation (BEC).It is found that the results corresponding to a large number of particles are approached quite rapidly as the number of bosons in the system increases. For large number of particles, results obtained within our iterative scheme are consistent with those of the semiclassical theory of BEC in an external potential based on the grand canonical treatment.Comment: 20 pages in RevTex with 4 Postscript figures. The e-mail addresses of the authors are `[email protected]',and `[email protected]