Confronting an identity crisis - how to "brand" systems engineering

Systems Engineering is not a new discipline; the term has been in use since World War II. Yet, while there has been no shortage of definitions of the term over the years (not all of which are consistent), there is little consensus on the scope of Systems Engineering. This is particularly true in relation to other overlapping disciplines such as System Dynamics, Operations Research, Industrial Engineering, Project Management, Soft Systems Methodology, Specialist Engineering, and Control Theory, which share many of the origins and techniques of Systems Engineering. This paper presents a landscape of disciplines and suggests that INCOSE should “brand” Systems Engineering strategically, defining explicitly its position within this landscape including its points of parity (overlaps) and points of difference with other disciplines. Actively branding Systems Engineering will broaden its appeal and attract more interest from stakeholders outside the current Systems Engineering community. INCOSE’s “market share” relative to its biggest systems competitor—Project Management—is falling, so even though INCOSE membership is rising, more needs to be done to promote the profession

Economic effects of prolonged clopidogrel therapy after percutaneous coronary intervention

ObjectivesThis study examined the incremental cost-effectiveness of extending clopidogrel therapy from one month to one year after percutaneous coronary intervention (PCI) in an unselected, heterogeneous patient population.BackgroundClinical trials suggest that prolonging clopidogrel therapy for up to one year after PCI reduces downstream cardiac events. However, clopidogrel therapy is costly and may increase bleeding risk.MethodsUsing decision analysis, we compared the outcomes and cost of prolonging clopidogrel treatment from one month to one year after PCI with the alternative strategy of discontinuing therapy one month after the procedure. Event rates were based on 3,976 PCI patients who were treated between January 1999 and December 2001 at the Duke Medical Center and received no more than one month of clopidogrel after the procedure. Baseline characteristics and event rates were obtained from Duke clinical information systems. The effect of prolonged clopidogrel therapy on event rates was based on the Clopidogrel for the Reduction of Events During Observation (CREDO) trial per-protocol data. Unit costs and the effect of myocardial infarction (MI) on life expectancy were based on published sources.ResultsExtending clopidogrel therapy from one month to one year after PCI cost $879 per patient and reduced the risk of MI by 2.6$15,696 per year of life saved. Economic attractiveness of therapy varied with baseline risk, the effect of prolonged therapy on MI risk, and the price of clopidogrel.ConclusionsProlonging clopidogrel therapy for one year after PCI is economically attractive, particularly in high-risk patients

Neural Coding of Movement Direction in the Healthy Human Brain

Neurophysiological studies in monkeys show that activity of neurons in primary cortex (M1), pre-motor cortex (PMC), and cerebellum varies systematically with the direction of reaching movements. These neurons exhibit preferred direction tuning, where the level of neural activity is highest when movements are made in the preferred direction (PD), and gets progressively lower as movements are made at increasing degrees of offset from the PD. Using a functional magnetic resonance imaging adaptation (fMRI-A) paradigm, we show that PD coding does exist in regions of the human motor system that are homologous to those observed in non-human primates. Consistent with predictions of the PD model, we show adaptation (i.e., a lower level) of the blood oxygen level dependent (BOLD) time-course signal in M1, PMC, SMA, and cerebellum when consecutive wrist movements were made in the same direction (0° offset) relative to movements offset by 90° or 180°. The BOLD signal in dorsolateral prefrontal cortex adapted equally in all movement offset conditions, mitigating against the possibility that the present results are the consequence of differential task complexity or attention to action in each movement offset condition

The impact of statistical adjustment on economic profiles of interventional cardiologists

AbstractOBJECTIVESThe objective of this study was to identify preprocedure patient factors associated with percutaneous intervention costs and to examine the impact of these patient factors on economic profiles of interventional cardiologists.BACKGROUNDThere is increasing demand for information about comparative resource use patterns of interventional cardiologists. Economic provider profiles, however, often fail to account for patient characteristics.METHODSData were obtained from Duke Medical Center cost and clinical information systems for 1,949 procedures performed by 13 providers between July 1, 1997, and December 31, 1998. Patient factors that influenced cost were identified using multiple regression analysis. After assessing interprovider variation in unadjusted cost, mixed linear models were used to examine how much cost variability was associated with the provider when patient characteristics were taken into account.RESULTSTotal hospital costs averaged $15,643 (median,$13,809), $6,515 of which represented catheterization laboratory costs. Disease severity, acuity, comorbid illness and lesion type influenced total costs (R2= 38%), whereas catheterization costs were affected by lesion type and acuity (R2= 32%). Patient characteristics varied significantly among providers. Unadjusted total costs were weakly associated with provider, and this association disappeared after accounting for patient factors. The provider influence on catheterization costs persisted after adjusting for patient characteristics. Furthermore, the pattern of variation changed: the adjusted analysis identified three new outliers, and two providers lost their outlier status. Only one provider was consistently identified as an outlier in the unadjusted and adjusted analyses.CONCLUSIONSEconomic profiles of interventional cardiologists may be misleading if they do not adequately adjust for patient characteristics before procedure

Early spears as thrusting weapons: Isolating force and impact velocities in human performance trials

Human hunting has been a cornerstone of research in human evolutionary studies, and decades worth of research programmes into early weapon systems have improved our understanding of the subsistence behaviours of our genus. Thrusting spears are potentially one of the earliest hunting weapons to be manufactured and used by humans. However, a dearth of data on the mechanics of thrusting spear use has hampered experimental research. This paper presents a human performance trial using military personnel trained in bayonet use. Participants thrusted replicas of Middle Pleistocene wooden spears into PermaGel™. For each spear thrust, impact velocity was recorded with high-speed video equipment, and force profiles were recorded using a force transducer. The results demonstrate that training improves performance when compared with previous experimental results using untrained participants, and that the mechanics and biomechanics of spear thrusting are complex. The trial confirms that previous spear thrusting experiments firing spears as projectiles are failing to replicate the entire spear thrusting event, and that crossbows are too powerful to replicate the low velocities involved in spear thrusting. In order to better understand evidence of spear thrusting in the archaeological record, experimental protocols accurately replicating and recording the mechanics of spear thrusting in the past are proposed

Gadolinium and nephrogenic systemic fibrosis: time to tighten practice

Nephrogenic systemic fibrosis (NSF) is a relatively new entity, first described in 1997. Few cases have been reported, but the disease has high morbidity and mortality. To date it has been seen exclusively in patients with renal dysfunction. There is an emerging link with intravenous injection of gadolinium contrast agents, which has been suggested as a main triggering factor, with a lag time of days to weeks. Risk factors include the severity of renal impairment, major surgery, vascular events and other proinflammatory conditions. There is no reason to believe that children have an altered risk compared to the adult population. It is important that the paediatric radiologist acknowledges emerging information on NSF but at the same time considers the risk:benefit ratio prior to embarking on alternative investigations, as children with chronic kidney disease require high-quality diagnostic imaging