Lean Systems: Soft OR in practice

Lean implementation involves eliminating all forms of waste (for example, defects or overproduction) and consists of many improvement strategies or systems such as mistake proofing (Poka-Yoke) and Single Minute Exchange of Die (a.k.a. quick changeover). The purpose of this study is to discuss a successful lean or waste elimination initiative for a building products company. Specifically, this study describes how mistake proofing and quick changeover systems were implemented using soft OR practices or Soft Systems Methodology (SSM). Essentially, SSM consisted of four sequential stages, namely (1) problem identification, (2) basic approaches to improvement, (3) making plans for improvement, and (4) translating improvement plans into reality. The study contributes in two ways: for practicing managers, it shows that at the core of lean is soft OR practices, and for academicians, it provides directions for future research

Improving labour relations performance using a Simplified Drum Buffer Rope (S-DBR) technique

The purpose of this research is to describe an implementation of Simplified Drum Buffer Rope (S-DBR), a scheduling methodology under Theory of Constraints, in service operations of a US military base. In doing so, this research contributes in two ways. For practitioners, this research is the first to show how S-DBR methodology can be utilised to improve the performance of labour relations. For academicians, this research is one of only a few to address the how questions of S-DBR use in a service context

Elements of paradoxes in supply chain management literature: A systematic literature review

This study reports the results of a systematic literature review investigating paradoxes in supply chain management. This issue is important because supply chain practitioners frequently face paradoxes in industry with little direction provided in supply chain literature. Investigating the years 1997 through 2019, we identified 64 articles as the basis of our research containing a total of 68 unique paradoxes. In identifying the paradox elements (PEs), we adopted paradox theory (PT) as the base theoretical approach, which was utilized in only 7 of the articles. We employed contingency theory, institutional complexity theory, and complexity theory to support our findings. For each paradox, we also extracted and summarized managerial insights for practitioners. This study addresses the emergent needs of investigating paradoxes in the supply chain management domain to extend the use of PT and complementary theories that can aid practitioners in how to efficiently manage the paradoxes they encounter in industry

Interactions in sustainable supply chain management: a framework review

Purpose – This study evaluates the research conducted among the interim, dyadic interactions that bridge the stand-alone measures of economic, environmental, and social performance and the level of sustainability, as suggested in the Carter & Rogers (2008) framework. Design/methodology/approach – This paper conducts a systematic literature review based on the Tranfield et al. (2003) method of the articles published in 13 major journals in the area of supply chain management between the years of 2010 and 2016. Results were analyzed using an expert panel. Findings – The area of research between environmental and social performance is sparse and relegated to empirical investigation. As an important area of interaction, this area needs more research to answer the how and why questions. The economic activity seems to be the persistent theme among the interactions. Research implications – The literature on the “ES” interactions is lacking in both theoretical and analytical content. Studies explaining the motivations, optimal levels, and context that drive these interactions are needed. The extant research portrays economic performance as if it cannot be sacrificed for social welfare. This approach is not in line with the progressive view of SSCM but instead the binary view with an economic emphasis. Practical implications – To improve sustainability, organizations need the triple bottom line (TBL) framework that defines sustainability in isolation. However, they also need to understand how and why these interactions take place that drive sustainability in organizations. Originality/value – This is the first study to examine the literature specifically dedicated to the essential, interim, dyadic interactions that bridge the gap between stand-alone performance and the TBL that creates true sustainability. It also shows how the literature views the existence of sustainability is progressive, but many describe sustainability as binary. It is possible that economic sustainability is binary, and progressive characterizations of SSCM could be the reason behind the results favoring economic performance over environmental and social

Catalog of Radio Galaxies with z>0.3. I:Construction of the Sample

The procedure of the construction of a sample of distant ($z>0.3$) radio galaxies using NED, SDSS, and CATS databases for further application in statistical tests is described. The sample is assumed to be cleaned from objects with quasar properties. Primary statistical analysis of the list is performed and the regression dependence of the spectral index on redshift is found.Comment: 9 pages, 6 figures, 2 table

Radio Continuum Imaging of High Redshift Radio Galaxies

We present sensitive radio continuum images at high resolution of 37 radio galaxies at z > 2. The observations were made with the Very Large Array (VLA) at 4.7 GHz and 8.2 GHz, with typical resolutions of 0.45'' and 0.25'', respectively. Images of total and polarized intensity, and spectral index, are presented. Values for total and polarized intensity, and values of rotation measures, are tabulated for the hot spots in each source. The positions of the radio nuclei are tabulated, along with a variety of other source parameters. Analysis of the polarization data reveals large rotation measures (RMs) towards six sources. We argue that the RMs are due to magnetized, ionized gas local to the radio sources. The magnitude of the RMs are in excess of 1000 rad/m/m (rest frame) for these sources. Drawing an analogy to a class of lower redshift radio galaxies with extreme RMs, we speculate that these sources may be at the centers of dense, X-ray emitting cluster atmospheres.Comment: ApJ (Supplement) (paper no. 33814

Circumstellar discs: What will be next?

This prospective chapter gives our view on the evolution of the study of circumstellar discs within the next 20 years from both observational and theoretical sides. We first present the expected improvements in our knowledge of protoplanetary discs as for their masses, sizes, chemistry, the presence of planets as well as the evolutionary processes shaping these discs. We then explore the older debris disc stage and explain what will be learnt concerning their birth, the intrinsic links between these discs and planets, the hot dust and the gas detected around main sequence stars as well as discs around white dwarfs.Comment: invited review; comments welcome (32 pages

Testing the inverse-Compton catastrophe scenario in the intra-day variable blazar S5 0716+71. I. Simultaneous broadband observations during November 2003

Some intra-day variable, compact extra-galactic radio sources show brightness temperatures severely exceeding 10^{12} K, the limit set by catastrophic inverse-Compton (IC) cooling in sources of incoherent synchrotron radiation. The violation of the IC limit, possible under non-stationary conditions, would lead to IC avalanches in the soft-gamma-ray energy band during transient periods. For the first time, broadband signatures of possible IC catastrophes were searched for in S5 0716+71. A multifrequency observing campaign targetting S5 0716+71 was carried out in November 2003 under the framework of the European Network for the Investigation of Galactic nuclei through Multifrequency Analysis (ENIGMA) together with a campaign by the Whole Earth Blazar Telescope (WEBT), involving a pointing by the soft-gamma-ray satellite INTEGRAL, optical, near-infrared, sub-millimeter, millimeter, radio, and Very Long Baseline Array (VLBA) monitoring. S5 0716+71 was very bright at radio frequencies and in a rather faint optical state during the INTEGRAL pointing; significant inter-day and low intra-day variability was recorded in the radio regime, while typical fast variability features were observed in the optical band. No correlation was found between the radio and optical emission. The source was not detected by INTEGRAL, neither by the X-ray monitor JEM-X nor by the gamma-ray imager ISGRI, but upper limits to the source emission in the 3-200 keV energy band were estimated. A brightness temperature Tb>2.1x10^{14} K was inferred from the radio variability, but no corresponding signatures of IC avalanches were recorded at higher energies. The absence of IC-catastrophe signatures provides either a lower limit delta>8 to the Doppler factor affecting the radio emission or strong constraints for modelling of the Compton catastrophes in S5 0716+71.Comment: 15 pages, 3 EPS figures, 3 tables, to appear in A&

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2–4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease