INFORMATION SYSTEMS OUTSOURCING: A MIXED INTEGER PROGRAMMING ANALYSIS

In the recent past, the trend toward outsourcing has become a major information systems phenomenon. Outsourcing is the subcontracting of various information systems subfunctions such as managing of data centers, operations, hardware support software maintenance, and even application software by user-firms to either incumbent vendors or outside vendors. Outsourcing is therefore emerging as a key approach for managing infonnation systems functions. In this research, we investigate the outsourcing bidding process pertinent to the selection of one subcontractor by a userfirm. We analyze bidding situations where the bidders have different levels of expertise and cost structures. The theoretical foundations for this research lie iii the theory of mechanism design (Myerson 1983), as well as the theory of imperfect information (Philips 1988) and incentive design (Ledyard 1989; McAfee 1986). We build a mixed integer programming model to represent what happens in an outsourcing bidding context involving a user-firm, an incumbent firm, and a challenger firm and explore the implications. The analysis is conducted over two different time horizons called the ex ante and the ex post periods. Two mixed-integer programming models are presented for two time horizons (in developing the model, we follow Kreps 1990). To reflect the different levels of expertise and cost structures of bidders, a discrete probability distribution is assigned to each bidder to approximate a bidder\u27 s true cost. A bidder\u27s true cost is private information, but its probability distribution is assumed to be common knowledge. An incumbent firm is assumed to have cost advantages over other bidders as a result of being familiar with the information needs of the user-firm. Therefore, the incumbent firm is assigned a cost probability distribution that is skewed toward low cost. The competing bidder\u27s cost structure is skewed toward high cost. The objective function of each model is formulated so as to minimize the expected cost subject to participation, and truthtelling constraints. Participation constraints indicate that each bidder participates only if a positive profit is given by the user-firm. Truth-telling constmints denote that each bidder prefers telling the truth to misrepresentation. The preliminary results of the models suggest that a policy of awarding incentives and levying penalties needs to be followed by the user firm. The results show that in order to induce the bidders to behave truthfully, some penalties would have to be levied and incentives would have to be provided. For example, if both the incumbent bidder and the challenger bid the same. the challenger is awarded the bid. If the incumbent firm is found to be inflating quotes, a penalty would have to be levied against the incumbent in the sense that the contract would be awarded to the challenger. Finally, in order to reward the bidder who quotes the true costs, subsides would have to be awarded. Thus, the models provide theoretical justification and guidelines for bidding behavior practices in the real world. Interestingly, both the ex-ante and ex-post models based on Krep\u27s assumptions show identical results. Implications of this finding need to be further explored in future research

Non-communicable Diseases and Depression: Evidence from South Africa

Although there are numerous studies of depression and its linkages with non-communicable diseases (NCDs), most rely on a single cross-section or a single wave of the National Income Dynamics Study (SA-NIDS) for South Africa, which does not allow for incorporation of individual unobservable effects. Such effects are potentially significant as it is frequently observed that there is considerable variation in depressive symptoms even when an old person suffers from common NCDs. We use correlated random effects probit model on the first 5 waves of SA-NIDS panel data collected every two years between 2008-2016/17 to examine the reverse association from Depression to selected NCDs, controlling for socio-economic and demographic characteristics. The analysis yields useful insights into the complex relationships between NCDs and depression. Policy options that focus on biological and behavioural links in the co-occurrence of NCDs and depression are examined. Of particular importance is integration of depression and NCD care in primary health care with a view to increasing prevention, screening, self-management, treatment and rehabilitation in order to achieve equitable, efficient and quality health services in South Africa

Aging, Depression, Non-Communicable Diseases and Disabilities in South Africa

This is the first study that offers a comprehensive analysis of depression among the old (60+ years) in South Africa. This study uses four waves of a panel survey of the South Africa National Income Dynamics Study (SA-NIDS) during 2008-2014. A state-of-art econometric methodology has been used to unravel the factors underlying depression among the old over the period 2008-2014. Depending on whether the dependent variable is binary (self-reported depression for ≥ 3 days in a week) or continuous (as in measures of overall depression and severe depression), we use random effects probit with Mundlak adjustment or simply random effects with Mundlak adjustment. Among the old, those more likely to be depressed are: those in their sixties, Africans and Coloureds, women, those suffering from multimorbidity, those with multiple limitations in ADLs, those in lower asset quartiles and individuals who suffered family bereavements. Factors that attenuate depression include marriage, pension, affluence, trust in a community and familiar neighbourhoods. An important feature of our study is the robustness of the key results. To reduce their depression, more public and private health care investment in the health and well-being of aged in South Africa is recommended

EXPLOITING HYPERTEXT VALUATION LINKS FOR BUSINESS DECISION MAKING: A PORTFOLIO MANAGEMENT ILLUSTRATION

In this paper we discuss the application of hypertext valuation links to decision support for business problems. Valuation links enable us to relate hypertext link traversal to computation in a way that affects the contents of a hypertext node while retaining the "browsing metaphor'' of hypertext. This helps to support quantitative or qualitative reasoning about business problems when described in terms of hypertext nodes that are computational in nature. We illustrate these ideas in the domain of securities analysis and portfolio management, where a "buy side" portfolio manager may need to clarify his understanding of the basis of a "sell side" securities analyst's recommendations about securities that are candidates for inclusion in a portfolio.Information Systems Working Papers Serie

Functional and radiological outcomes of distal humerus fractures treated with pre-contoured locking compression plate

Background: Distal humerus intra-articular fractures are one of the complicated fractures managed by orthopaedic surgeons. We did a prospective and a retrospective study on 21 patients with these fractures treated with pre-contoured locking compression plate.Methods: The 21 patients in this series were followed for a minimum of 1 year. The prospective study cases were followed at 3 months, 6 months and annually. The rating system of the Mayo elbow functional scoring system was used. The radiological evaluation was done using standard AP and lateral views.Results: We had 14 patients with range of motion of 50-100 degrees. There was only one patient with range of motion of <50 degrees. 6 patients had the maximum range motion of >100 degrees. We had 6 (23.57%) excellent, 9 (42.85%) good, 5 (23.80%) fair and 1 (4.7%) poor in the Mayo elbow scoring at the end of 1 year. We were able to compare our outcomes with a study done by Kumar et al done in 2017. They had 27 (89.66%) of excellent and good results as opposed to 27 (79.4%) in our study. Out of 21 patients in our study 17(80.95%) patients had good 11 (52.5%) / excellent 6 (28.5%) results. This was comparable with Jupiter et al. His study of 34 patients 26 (79.40/0) patients showed good 14 (41%) / excellent 13 (38.4%) result.Conclusions: Pre-contoured locking compression plate appears to be technically an ideal implant for comminuted osteoporotic bone providing an angle stable construct

Cruciate retaining versus posterior-stabilized total knee arthroplasty: a short-term comparative study

Background: Total knee arthroplasty has got excellent results. Among the techniques (posterior-stabilized vs posterior cruciate retaining total knee arthroplasty) it is unclear whether one design has superior outcome over another. The purpose of the present study was to directly compare clinical and radiological outcomes of these two designs.Methods: A prospective study involving 36 patients who received a cruciate-retaining implant were compared to 30 patients who received posterior-stabilized prosthesis. At 3 months follow-up time clinical and radiological evaluation done and results were analyzed.Results: At 3 months follow-up time mean knee society scores improved from 49.9/46.9 (objective/subjective score) points to 80.9/82.5 points in the cruciate-retaining group and from 48.2/43 (objective/subjective score) points to 80.4/80.2 points in the posterior-stabilized group. The ranges of motion was 117.2° (range, 90° to 130°) and 125.3° (range, 100° to 140°) in the cruciate-retaining and posterior-stabilized group respectively, at 3 month follow-up. One patient had post-operatively periprosthetic fracture reported after 2 weeks (treated conservatively), one had superficial infection (treated with dressing) and one patient with superfical infection required debridement.Conclusions: This study did not conclusively demonstrate the superiority of one knee design over the other, suggesting that the choice of implant should be based on surgeon preference, patients knee dimensions, pre-op knee deformity and existing pathology of the posterior cruciate ligament

Audience Gatekeeping in the Twitter Service: An Investigation of Tweets about the 2009 Gaza Conflict

Twitter is a social news service in which information is selected and distributed by individual members of the tweet audience. While communication literature has studied traditional news media and the propagation of information, to our knowledge there have been no studies of the new social media and their impacts on the propagation of news during extreme event situations. This exploration attempts to build an understanding of how preexisting hyperlink structures on the Web and different types of information channels affect Twitter audiences’ information selection. The study analyzes the concentration of user-selected information sources in Twitter about the 2009 Israel-Gaza conflict. There are three findings. First, a statistical test of a power-law structure revealed that, while a wide range of information was selected and redistributed by Twitter users, the aggregation of these selections over-represented a small number of prominent websites. Second, binomial regression analyses showed that Twitter user selections were not constituted randomly but were affected by the number of hyperlinks received and the types of information channels. Third, temporal analyses revealed that sources via social media channels were more prominently selected especially in the later stages of the news information lifespan

Short term analysis of total hip replacement done with constrained acetabular component - functional and radiological outcome

Background: Dislocation remains at the forefront of complications after primary total hip arthroplasty (THA). In our study, we talk about the use of constrained liners and its outcomes in an unstable hip.Methods: The total number of patients included in the study was 15. The total number of hips in the study were 15. The age group of the patients varied between 51 years and 89 years with mean age group of 73 years. The most common indication in our study was dislocation contributing 60% (n=9) of the hips.Results: The post-operative mean Harris hip score (HHS) at immediate post-operative was 67.6. There was a gradual improvement in the HHS through 6 months (77.6), one year (83.3), two years (86.7) and 3 years (90.33). There were no cases with post-operative septic or aseptic loosening in the radiological analysis. The mean cup inclination was 34.3. Out of the 13 hips, in eight hips the femoral stem was in varus. Five hips had a centrally placed femoral stem. Stability management in THA have seen the component design take centre stage, primarily with the use of larger diameter femoral heads and the rise in popularity of constrained acetabular liners (CAL). Several authors have done studies which talk about the stability of this implant design and the reliability of this implant in unstable hips and in hips where instability was expected.Conclusions: In our study, proximal femur tumours, dislocated total hips, abductor insufficiencies and aseptic loosening all showed good results