On revenue maximization for selling multiple independently distributed items

Consider the revenue-maximizing problem in which a single seller wants to sell k different items to a single buyer, who has independently distributed values for the items with additive valuation. The case was completely resolved by Myerson’s classical work in 1981, whereas for larger k the problem has been the subject of much research efforts ever since. Recently, Hart and Nisan analyzed two simple mechanisms: selling the items separately, or selling them as a single bundle. They showed that selling separately guarantees at least a fraction of the optimal revenue; and for identically distributed items, bundling yields at least a fraction of the optimal revenue. In this paper, we prove that selling separately guarantees at least fraction of the optimal revenue, whereas for identically distributed items, bundling yields at least a constant fraction of the optimal revenue. These bounds are tight (up to a constant factor), settling the open questions raised by Hart and Nisan. The results are valid for arbitrary probability distributions without restrictions. Our results also have implications on other interesting issues, such as monotonicity and randomization of selling mechanisms.     

Occupational performance and strategies for managing daily life among the elderly with heart failure

Abstract

Aim: The aim of this study was to describe experiences of limitations in occupational performance and strategies for managing daily activities among the elderly with chronic heart failure (CHF). Methods: Ten participants from primary healthcare with a confirmed diagnosis of CHF were interviewed. The interviews were analysed using qualitative content analysis. Results: The first theme, “Redefining an active life, aware of one’s impaired body”, was based on four sub-themes: realizing one’s limited activity ability; striving to preserve an active life; focusing on meaningful activities; and changing vs. not changing habits and roles. The second theme, “Planning activities and balancing the degree of effort”, was based on three sub-themes: limiting, organizing, and rationalizing activities; adjusting activities to today’s ability; and using technology and adapting the environment. Conclusions: Elderly people with CHF are struggling with an ongoing process of occupational adaptation due to periodical physical decline and fluctuating day-to-day ability. This highlights a need for information on strategies from a holistic perspective and client-centred occupational therapy interventions.     

A pH-triggered delayed-release chronotherapeutic drug delivery system of aceclofenac for effective management of early morning symptoms of rheumatoid arthritis

Abstract

Context: Rheumatoid arthritis (RA) is differentiated as an early morning exacerbation of the core arthritis condition associated with increase in pain and stiffness in joints and necessitate for medication. Objective: The aim of the present work was to develop and optimise a pH-triggered delayed-release colon-specific aceclofenac microspheres and to accomplish chronotherapy of RA. Methods: A 3-factor, 3-level Box–Behnken design (BBD) was used to optimise selected variables. Developed formulation was evaluated for in vivo delayed response and anti-arthritis activity in rats. Results: The particle size and encapsulation efficacy of these microspheres were 117.36?±?10.54?µm and 85.06?±?5.85%, respectively. Optimised formulation was analysed by SEM, DSC, X-RPD and FTIR. The in vivo evaluation reveled delayed anti-inflammatory activity in carrageenan-induced rats and anti-arthritic activity in freund’s adjuvant-induced arthritis rats. Conclusion: The optimised aceclofenac microspheres formulation is potential for the chronotherapy of early morning symptoms of RA.     

Using apprenticeship communication flow as an ergonomic design input for future OR systems

Removing the gallbladder is a relatively simple laparoscopic operation. Tissue trauma, caused by laparoscopic cholecystectomy, is usually minimal. Misidentifying the cystic duct and artery and the common hepatic duct represents the most severe complication. However, the Critical View of Safety (CVS) technique reduces the risk of trauma, by accomplishing a safe 360° identification of the cystic duct origin at the gallbladder neck [5]. This technique is employed and trained at the Erasmus Medical Centre (EMC), Rotterdam, The Netherlands.

?This study presents the potential value of a training device which residents can use during practice. This training device must cover both user friendliness and information supply. The current information supply was studied subjectively; the CVS protocol and the users' experience were studied both objectively and subjectively. The results of these studies show that the present information supply is not satisfactory, that there is a CVS protocol which can be easily used in a training device, and that most actions defining the cystic duct during operation revert on users' experience. Therefore, it is desirable to design a new training device according to the experience of the target group and the protocols, and taking into account an optimal human‐product interaction.     

聚能光谱磁共振MAGNETOMSpectra实现创新人性化设计

讨论MRI系统人性化设计的概念．并总结了其在西门子MAGNETOMSpectra产品的实现。     

Home Modifications for the Elderly

With society placing high positive value on independent living for the elderly, the need for home modification is growing. This paper will describe current information as well as psychosocial implications the occupational therapist should consider when collaborating with their elderly clients who wish to remain at home and “age in place.”     

Energy expenditure during physiotherapist-assisted and self-treatment in cystic fibrosis

Cystic fibrosis (CF) results in increased energy requirements at rest. However, the energy expended during physiotherapy management is unknown. The aim of this study, therefore, is to examine the energy expended during two commonly used forms of chest physiotherapy in CF subjects. Twenty-six CF subjects completed a randomised crossover trial with 48 hours between treatments. Two regimens of treatment were conducted: therapist-assisted treatment (active cycle of breathing, ACBT, with percussion, vibration), and independent treatment (ACBT alone, under the supervision of a physiotherapist). Subjects completed pulmonary function tests before and after either treatment. Indirect calorimetry and oximetry parameters were recorded at rest, during, and following treatment. Treatment groups were compared using ANOVA and two-sample crossover t-tests. When compared to resting values, physiotherapy treatment resulted in significant increases in VO₂, VCO₂ and respiratory exchange ratio. No difference was evident between treatment regimens for the change in VO₂ between baseline and treatment. The increase in ventilation (baseline to treatment) was significantly greater for the therapist-assisted treatment. The therapist-assisted ACBT was associated with a significant carryover effect for forced expiratory flow at 50% of vital capacity (FEF₅₀). Oxygen requirements for the two treatments were similar. However, the assisted regimen resulted in greater changes in minute ventilation during treatment and improved 48-hour post-treatment pulmonary function after only one treatment session. These findings suggest that the inclusion of percussion and vibration within the ACBT may influence respiratory muscle activity during treatment and result in improved pulmonary function.     

Measuring impact of environmental factors on human functioning and disability: a review of various scientific approaches

Purpose.?The objective of this paper is to present a framework for systematically describing different approaches to measure environmental factors (EF) and to discuss some strengths and weaknesses of these approaches.

Methods.?Identification of suitable criteria for ordering measurements of EF was based on an analysis of existing reviews, a qualitative literature review and feedback from experts. Items of selected EF measures were linked to the International Classification of Functioning, Disability and Health.

Results.?Experimental and observational designs for the study of EF are distinguished and illustrated with examples. Approaches to study EF are differentiated into those directly measuring an environmental interaction with function and those relying on an independent assessment of environmental features. By applying these criteria, a three-dimensional matrix framework for measurement of EF in observational studies is developed.

Conclusion.?The acknowledgement of different measurement approaches to the scientific study of EF is one pathway towards an increased understanding of the connection between environments and functioning. Many different measures may be used to approximate the realities of disabling or enabling environments. This review provides an initial framework for improving our fundamental comprehension of the complexity of the measurement of EF in the context of human health and disability.