Deferral Time Research Articles

Integrated geo-techno-economic and real options analysis of the decision to invest in a medium enthalpy deep geothermal heating plant. A case study in Northern Belgium

Deep geothermal energy (DGE) is a renewable energy source that is considered to cause a low global warming impact. The potential of DGE for heating is widespread and interest in deep geothermal heating (DGH) has been growing in Europe to help achieving the decarbonization of the heating mix. Nevertheless, despite its large potential, DGH development in Europe remains underexplored. DGH investments are hindered by the risks born by geological and market uncertainties. However, various flexibility options inherent to the development process, such as the option to abandon or defer, could partly mitigate these risks. To account for managerial flexibility in the investment analysis, this study suggests a novel real options (RO) framework. The RO model splits DGH development into five phases, and considers several compound options and geological and market uncertainties to investigate the timing and value of DGH development at the Campine Basin in Northern Belgium. The RO model is coupled to a geo-techno-economic model and is solved using the Least Squares Monte Carlo algorithm. The RO analysis finds a 51% probability of abandonment and an average deferral time for the development of 12 years. The abandon option mitigates the risk of large financial losses in case of inadequate geological conditions. The defer option allows the investors to wait for more favorable market conditions before investing, to increase the project value. The results show that DGH development in the investigated area is not economically desirable. However, the investors' flexibility increases the project value by 12.16 million EUR, compared to a conventional techno-economic analysis. The implementation of supporting policy measures improves the economic performance of the plant. The consideration of flexibility leads to supporting policy measures with 3–4 times lower governmental expenditure, compared to a conventional techno-economic analysis. This study shows that a RO approach is more suitable to investigate DGH investments than static techno-economic methods. The inclusion of flexibility allows for identifying development pathways that increase the project value and for designing more cost-efficient supporting policy schemes.

DOP70 Prevalence and severity of bowel urgency in Crohn’s Disease: Results from the Communicating Needs and Features of IBD Experience (CONFIDE) Survey

Abstract Background Bowel urgency (BU) affects patients with Crohn’s disease (CD); however, its prevalence and severity are unclear. Here, data from Communicating Needs and Features of IBD Experiences (CONFIDE) study were used to understand the burden and impact of BU among patients with moderate-to-severe CD. Methods CONFIDE is an online, quantitative, cross-sectional survey exploring the experiences and impact of symptoms on patients with CD or ulcerative colitis in Europe (France, Germany, Italy, Spain, and UK), United States (US) and Japan. Criteria based on previous treatment, steroid use, and/or hospitalization defined moderate-to-severe CD. Patients were asked about bowel movement deferral time with response options ranging from able to wait ≥15 minutes (mins) to sometimes unable to make it to the bathroom in time. Patients currently experiencing BU (in last month) rated BU severity in the last 3 days using the Urgency Numeric Rating Scale (NRS, 0-10), a content-validated patient-reported instrument. CD data from Europe and US are presented here using descriptive statistics. Results Surveys were completed by 547 European (male [M]=55.4%, mean age 38 years) and 215 US (M=54.9%, mean age 40.9 years) patients with CD. Current BU (over the past month) was reported by 38% of patients in Europe and 42.3% in US. More than one-third of all patients in both Europe and US reported that over the last 3 days, they needed to get to the bathroom within 5 mins, and 1.8% European and 2.8% US patients were sometimes unable to make it to the bathroom in time. Among patients who reported currently experiencing BU, 46% reported the need to get to the bathroom within 5 mins and 3% reported sometimes being unable to make it to the bathroom in time in both Europe and US. Shorter deferral times were reported by those with higher mean Urgency NRS scores (Table). Mean (SD) Urgency NRS scores in patients with a deferral time <5 mins vs those with a deferral time >5 mins were 7.0 (1.7) vs 6.5 (2.1) among European and 7.3 (1.5) vs 6.7 (1.9) among the US patients. Most European and US patients reported experiencing BU, BU-related accidents, and/or wearing diaper/pad/other protection due to fear/anticipation of BU-related accidents at least once a month in past 3 months (Figure). Conclusion Patients with moderate-to-severe CD reported similar experiences of BU in the Europe and US, with most patients reporting currently experiencing BU and wearing diaper/pad/protection due to fear of BU-related accidents at least once a month. Patients currently experiencing BU had short deferral times, often having to reach the bathroom in ≤5 mins. Given the substantial burden and impact, BU should be considered when assessing patients with CD.

A column generation-based approach for the adaptive stochastic blood donation tailoring problem

Managing blood donations is a challenging problem due to the perishability of blood, limited donor pool, deferral time restrictions, and demand uncertainty. The problem addressed here combines two important aspects of blood supply chain management: the inventory control of blood products and the donation schedule. We propose a stochastic scenario-based reformulation of the blood donation management problem that adopts multicomponent apheresis and utilises donor pool segmentation into here-and-now and wait-and-see donors. We propose a flexible donation scheme that is resilient against demand uncertainty. This scheme enables more flexible donation schedules because wait-and-see donors may adjust their donation schedules according to the realised values of demand over time. We propose a column generation-based approach to solve the associated multi-stage stochastic donation tailoring problem. The numerical results show the effectiveness of the proposed optimisation model, which provides solutions with less than a 7% optimality gap on average with respect to a lower bound. It also improves the operational cost of the standard donation scheme that does not use wait-and-see donors by more than 18% on average. Utilising multicomponent apheresis and flexible wait-and-see donations are suggested for donation organisations because they yield significant cost reductions and resilient donation schedules.

Does Working Capital Management Impact How Well a Company Performs? Panel Data Analysis on the Textile Industries of Bangladesh

Managing working capital is vital to the expansion and development of manufacturing companies. The performance of Bangladeshi textile industries and the implications of working capital management are the main focus of this study. Working capital is represented by the inventory conversion period, receivable collection cycle, payable deferral cycle, and cash conversion cycle, whereas firm performance is determined by ROA. From 2013 to 2022 ten years panel data were collected from the annual reports of ten listed textile companies of Bangladesh. Panel Least Square (PLS), fixed affect, random effect, and the Hausman test were all executed using the STATA program to determine the influence of independent factors on the dependent factor. The ROA of Bangladesh's textile industries was found to be significantly affected by the Inventory Conversion time, Receivables Collection time, and Cash Conversion Circle, but not by the Payable Deferral time.

Monitoring syphilis serology in blood donors: Is there utility as a surrogate marker of early transfusion transmissible infection behavioral risk?

In Canada the time deferral for gay, bisexual, and other men who have sex with men (gbMSM) was progressively shortened (lifetime, 5 years, 1 year, 3 months). Here we describe trends in syphilis rates (a potential sexual risk marker) and risk behaviors from blood donors in the past 12 years. Syphilis positivity in 10,288,322 whole blood donations (January 1, 2010-September 10, 2022) and gbMSM deferral time periods, donation status, age, and sex were analyzed with logistic regression. Overall, 26.9% syphilis positive and 42.2% controls (matched 1:4) participated in risk factor interviews analyzed by logistic regression. Syphilis rates were higher in first-time donors (OR 27.0, 95% CI 22.1-33.0), in males (OR 2.3, 1.9-2.8) and with the 3-month deferral (OR 3.4, 2.6-4.3) during which the increase was greater for first-time males (p < .001) but similar for male and female repeat donors (p > .05). Among first-time donors, histories of intravenous drug use (OR 11.7, 2.0-69.5), male-to-male sex 7.8 (2.0-30.2) and birth in a high prevalence country (OR 7.6, 4.4-13.0) predicted syphilis positivity; among repeat donors, history of male-to-male sex (OR 33.5, CI 3.5-317.0). All but 1 gbMSM syphilis-positive donors were noncompliant with the gbMSM deferral. About a quarter of first-time interviewed case donors had history of syphilis; 44% were born in a high-prevalence country. Rising syphilis rates in donors correlates with the general population epidemic. Recent infection rates rose similarly in males and females. GbMSM history may contribute to donor syphilis rates but shortening time deferrals appears unrelated.

Analysis of deferral times in patients diagnosed with acute appendicitis

IntroductionThere are still controversies regarding the time of surgical management for acute appendicitis (AA). The main objective of this study was to recognize the surgical deferral time in patients with acute appendicitis and its relationship with the severity of presentation. Materials and methodsWe performed a retrospective review of prospectively collected data of all patients with acute appendicitis undergoing appendectomy from August 2018 to August 2020 in an academic, public hospital. Elapsed time from arrival to the emergency room to skin incision was determined. Patients were divided into three groups based on the elapsed time: less than 6 h, between 6 and 12 h, and more than 12 h. ResultsA total of 782 patients were included. Of them, 443 (56.6%) patients had a surgical deferral time of less than 6 h, 238 (30.4%) patients between 6 and 12 h, and 101 (13%) patients of more than 12 h. Patients with more than 12 h of surgical deferral time had a more complicated clinical presentation (P = 0.013), a higher frequency of abscess formation (P = 0.022), higher requirement for the use of surgical drainage (P = 0.018), and longer length of hospital stay (P = <0.001). ConclusionSurgical deferral >12 h was associated with a higher incidence of complicated appendicitis, intra-abdominal abscesses, and overall hospital stay. However, in the multivariate analysis, only total evolution time, from the first symptom to surgery, was a significant independent predictor of complicated appendicitis.

Situation-Aware Survivable Network Design for Tactical Environments

A tactical sensor network is a representative safety-critical environment that should satisfy strict guarantee of the requirements of tactical traffic. However, because of the lack of infrastructure in a military network environment, resource constraints on wireless channel and nodes can cause problems such as network congestion and packet collision. If critical tactical data is lost or does not arrive on time, it can degrade the efficiency of military operations and even threaten the survival of soldiers. To resolve this critical issue, we propose a situational backoff reset algorithm that utilizes a quality of service (QoS) field information to determine the priority of received tactical packets and control the deferral time of low-priority traffic. From a packet routing path connectivity perspective, we propose a branch node-based routing algorithm in order to provide a resilient path by excluding the isolated single path. Our simulation results demonstrate that the proposed solution can prioritize tactical traffic from the channel preemption perspective and construct a robust end-to-end path avoiding an isolated single path.

Determination of Appropriate Deferral Time for Repeat Apharesis Platelets Concentrate Donation in Abuja, Nigeria

Background: Plateletpheresis is the process by which a therapeutic adult dose of platelet concentrate is produced from a single donor using automated cell separator equipment. Recently, the demand for Apheresis Platelets concentrate transfusions has been increasing in our hospitals. This has been attributed to increased cases of malignancy associated bone marrow suppression and various other causes of thrombocytopaenia and thrombopathies. The Increasing use of myeloablative chemotherapy in treatment of haematological and other malignancies also results in transient severe fall in platelet count. The demand generally outstrips the supply necessitating the need to search for additional donor sources to increase the supply of platelets for transfusion. Is it therefore possible to reduce the time interval between plateletpheresis while maintaining donor safety? Aims and Objectives: The aim of the study was to determine the platelets recovery time after platelets concentrate donation with a view to determining the appropriate deferral time for repeat plateletpheresis Methods: The study was conducted at the National Hospital Abuja. Fifty seven healthy plateletpheresis donors were recruited over a period of seven months and their haematological parameters were analyzed on days 0, 2 and 7 post donation. We excluded donors whose pre-donation platelet count were less than 200 x 109/L Results and Analysis: Analysis was done in only forty eight (48) donors as nine (9) participants withdrew before the end of the study. The results show There was a significant decrease in the platelets counts (p &lt;0.001), with subsequent good platelets recovery post donation (Pre: 259.83±44.61 x 109/L; Post - Day 0: 205.29±36.77 x 109/L, day 2: 216.88±32.71 x 109/L and day 7: 240.3±41.83 x 109/L). The apheresis donors recovered 64.29% of the lost platelets by day 2 of donation and subsequently attain 92.49% of pre-donation count within 7 days of donation. There was a statistically significant transient increase in the immediate post donation haemoglobin concentration (14.72±1.32)g/dL but this gradually reduced on day 2 (13.75±1.04)g/dL and 13.83±1.04g/dL on day 7 showing no significant different from the pre-donation Hb of 13.96±1.02g/dL Conclusion: This study has shown statistically significant platelets recovery 7 days after plateletpheresis making a 7 day deferral for repeat plateletpheresis feasible in our environment. The study also shows feasibility of a 2 days deferral as recommended by AABB. Strict monitoring and pre-donation evaluation of donors should be done to prevent any adverse events such as anaemia and thrombocytopenia. Disclosures No relevant conflicts of interest to declare.

Posterior tibial nerve stimulation in the treatment of fecal incontinence: a systematic review.

Fecal incontinence severely impacts on quality of life, causing stigmatization and social exclusion. Posterior tibial nerve stimulation (PTNS) is one technique used for treatment. This systematic review aims to assess the effectiveness of PTNS for the treatment of fecal incontinence. A literature review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) declaration. Pubmed, Scopus, Web of Knowledge and PEDro databases were searched for both randomized clinical trials and cases series. The outcome variables were treatment effectiveness, severity of incontinence and quality of life; all were measured in the short, mid and long-term after performing both percutaneous and transcutaneous PTNS. Twenty-three studies met the selection criteria. Two clinical trials found significant differences in treatment effectiveness compared to the placebo response. Fifteen cases series observed significant differences in terms of effectiveness, severity and quality of life. All clinical trials achieved a reduction in the number of incontinence episodes and an increase in the deferral time for defecation. Optimal results were achieved by interventions consisting of one or two weekly sessions of a 30-60 minutes duration and the use of pulse widths of 200 µs and frequencies of 10-20 Hz. Percutaneous stimulation did not demonstrate better results compared to transcutaneous application. PTNS is an effective technique for the treatment of fecal incontinence, although long-term interventions are required in order to prolong its effects in the long-term.

Sensor Node Failure Detection using Multiway Tree based Round Trip Path in Wireless Sensor Networks

To upgrade the Quality of Services among the sensor node correspondence in WSN, the recognizing confirmation of sensor node range, ID of reduced sensor nodes, amounts of sensor nodes included, recognizable proof of issue nodes are the over the top testing civil argument. The main objective of this work is to identify the faulty node, its readings, detection of the malfunctioning nodes. Round Trip Path is used to evaluate the Round Trip Delay time with which the information about the sensor nodes is accomplished. In perspective of the round trek deferral time esteem, the deficiency node is diagnosed. The detection of the faulty node is determined by the previous work but the obtained path for the detection is more. In the proposed Multi way Tree based Round Trip Path (MTrTP) system, the faulty node is identified with less number of paths when compared to the existing work. In this method, the shortcoming sensor node is recognized, by measuring the RTD time of every single possible way and the results are appeared differently in relation to edge esteem. MTrTP system is had a go at using six at mega sensor nodes with Xbee Series2 ZigBee modules. By taking a gander at the distinctive results got using the RTD examination, MTrTP strategy exhibits that, it will give raised results in regards to number of RTP and investigation time. In this work, diverse gained results are plotted and the relating examinations are inspected. The plotted result of the existing work and the current work is compared. The proposed work has much more advantages when compared to existing because the number of path obtained and the analysis time for the fault node detection is less. Thus, the detection of the fault node is determined by the MTrTP algorithm. Therefore, the lifetime of the wireless sensor network, the degree of coverage and connectivity among the sensor network are increased. This work can be used for industrial automation and all WSN applications.

PWE-014 Development of an Optimum Treatment Regimen for Transcutaneous Posterior Tibial Nerve Stimulation for Faecal Incontinence

IntroductionPosterior tibial nerve stimulation (PTNS) is an effective treatment for faecal incontinence (FI). A wide range of PTNS regimens have been reported. The aim of this study was to determine...

Pulsed Feedback Defers Cellular Differentiation

Author SummaryHow long should a cell wait to respond to an environmental change? While many pathways such as those affecting chemotaxis respond to environmental signals quickly, in other contexts a cell may want to defer its response until long after the signal's onset—sometimes waiting multiple cell cycles. How can cells create “timers” to regulate these long deferrals? We study this question in the bacterium Bacillus subtilis, which responds to stress by transforming into a dormant spore. We show that B. subtilis can defer sporulation for extended time periods by first undergoing multiple rounds of growth and proliferation, and only then sporulating. The timer for this deferral is a pulsed positive feedback loop, which ratchets up the concentration of the sporulation master-regulator Spo0A to a critical level over multiple cell cycles. Finally, using mathematical modeling, we illustrate how a novel dynamic feedback mechanism, “polyphasic positive feedback,” lets cells defer sporulation more robustly than with other circuit strategies. Developing techniques that can access pulsing and time-delay dynamics with higher time resolution will enable us to determine if this polyphasic strategy provides a general design principle for the regulation of multi-cell-cycle deferral times seen in other systems.

A fuzzy multi‐objective balanced scorecard approach for selecting an optimal electronic business process management best practice (e‐BPMBP)

PurposeThe rapid intensification of the internet and electronic commerce diffusion has given rise to electronic business process management (e‐BPM) which enhances the overall connectivity of the business processes. However, when confronted by the range of e‐BPM best practices (e‐BPMBPs), organizations struggle to identify the one most appropriate to their needs. The paper aims to address these issues.Design/methodology/approachThe paper proposes a novel fuzzy group multi‐objective method for e‐BPMBP evaluation and selection. First, a fuzzy group linear assignment method is used to rank the e‐BPMBPs drawing on the four perspectives of a balanced scorecard (BSC). Second, a fuzzy group real options approach is used to estimate the financial values of the ranked e‐BPMBPs. Third, a four‐objective assignment model is used to select the optimal e‐BPMBP in deferral time with respect to their rankings, financial values, and a series of pertinent constraints.FindingsThe contribution of the proposed method is threefold: it is grounded in the four perspectives of a BSC, it considers imprecise or vague judgments which lead to ambiguity in the decision process, and it uses a meaningful and robust multi‐objective model to aggregate both qualitative judgments and quantitative data. A case study is presented to demonstrate the applicability of the proposed framework and to exhibit the efficacy of the procedures and algorithms.Originality/valueThe novel fuzzy group multi‐objective framework for e‐BPMBP evaluation and selection proposed in the paper takes into consideration (1) the qualitative and quantitative criteria and their respective value judgments; (2) the verbal expressions and linguistic variables for qualitative judgments which lead to ambiguity in the decision process; and (3) imprecise or vague judgments.

A hybrid fuzzy real option analysis and group ordinal approach for knowledge management strategy assessment

The intensity of global competition and ever-increasing economic uncertainties has led organizations to search for more efficient and effective ways to improve organizational productivity by investing in knowledge management (KM) initiatives. In this research, we propose a framework to assess KM investment opportunities. Precise and crisp information is fundamentally indispensable in strategic investment assessment. However, the information concerning future investment opportunities in the real world is often imprecise or ambiguous. Initially, fuzzy real option valuation is used to estimate the value of the KM strategies. Next, a multi-criteria decision-making model is proposed to determine the optimal KM strategy in deferral time. Then, a group ordinal approach is used to capture and quantify the underlying uncertainties in the valuating process. Finally, the optimal KM strategy and the best time to implement this strategy is determined by a novel objective decision-making model. The contribution of this paper is fourfold: (1) it addresses the gaps in KM literature on the effective and efficient assessment of KM investment opportunities; (2) it provides a comprehensive and systematic framework that combines real option analysis with a group ordinal approach to assess KM investment strategies; (3) it considers fuzzy logic and fuzzy sets to represent ambiguous, uncertain or imprecise information; and (4) it uses a real-world case study to demonstrate the applicability of the proposed framework and exhibit the efficacy of the procedures and algorithms.

One-Year Deferral Method for Estimating Avoided Transmission and Distribution Costs

This paper presents a new method for estimating avoided transmission and distribution costs associated with small load reductions, named the one-year deferral method. It is established on the basis of the system planner's actual response to a small reduction in the forecast annual peak load. This paper has also explored the noninteger deferral time (i.e., a fraction of a year) in the present worth method, which is seemingly inconsistent with the system planning practice. In addition, as allowed by the new method, the effect of the size and type (shape) of a load reduction stream (i.e., a series of reductions in the forecast annual peak loads) on avoided costs is studied, which is important for determining generic avoided cost values intended for various applications.

Ileal pouch-anal anastomosis (IPAA): functional outcome after postoperative pelvic sepsis

The ileal pouch-anal anastomosis (IPAA) has become a standard procedure for patients with ulcerative colitis requiring surgical intervention. The technique has greatly improved and, since 1990, all patients at Huddinge University Hospital have been operated on with the double stapled technique. Pelvic sepsis is one of the most serious complications postoperatively, and, according to previous reports, leads to impaired function of the pouch and, in some cases, extirpation of the pouch. The purpose of this study was to find out if pelvic sepsis postoperatively after IPAA leads to impaired functional outcome at long-term follow-up. One hundred consecutive patients with ulcerative colitis operated on between 1990 and 1997 with double stapled J-shaped pouches were followed prospectively with a standardised questionnaire, clinical follow-up and endoscopy of the pouch. The function of the pouch has been evaluated at a minimum of 2 years after surgery to compare the functional outcome between patients with and without pelvic sepsis postoperatively. Twelve patients developed pelvic sepsis postoperatively. No significant differences were found in pouch evacuation frequency, incontinence, deferral time, usage of protecting pads, skin irritation, evacuation problems, diet, usage of medication or social handicap. There was one failure in the control group. In this study, no evidence was found that suggested pelvic sepsis postoperatively impairs functional outcome after IPAA at long-term follow-up.

Erratum

BJU InternationalVolume 95, Issue 6 p. 924-924 Free Access Erratum First published: 24 March 2005 https://doi.org/10.1111/j.1464-410X.2005.05492.xCitations: 1AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat In [1], the following error occurred on page 337. Figure 3 was reproduced incorrectly. The correct version appears below. Fig. 3. (a) A schematic of the effect of urgency on the micturition cycle. During an urgency episode, the desire to void increases abruptly, resulting in a void and shortening the intervoid interval, and reducing the volume voided. Therapy can eliminate urgency episodes and thus normalize the intervoid interval. (b) A schematic of two micturition cycles terminated by voids associated with urgency episodes. A refractory period, defined as the interval between voiding and the next urgency episode, can be measured and may be affected by therapy. A warning or deferral time can also be measured as the time from the onset of urgency to voiding. We apologize for this error. REFERENCES 1 Chapple CR, Artibani W, Cardozo LD, Castro-Diaz D, Craggs M, Haab F, Khullar V, Versi E. The role of urinary urgency and its measurement in the overactive bladder symptom syndrome: current concepts and future prospects. BJU Int 2004; 95: 335– 40 Wiley Online LibraryWeb of Science®Google Scholar Citing Literature Volume95, Issue6April 2005Pages 924-924 ReferencesRelatedInformation

Gains and losses with stapling and omission of loop ileostomy in pelvic pouch surgery: a matched control study.

After 10 years experience of pelvic pouch surgery with handsewn pouch and ileoanal anastomosis, mucosectomy, and covering loop ileostomy, the surgical technique was altered. Twenty patients were operated on with staple technique in pouch and ileoanal anastomosis but without mucosal proctectomy and loop ileostomy. This study group was compared with a matched control group of patients from our previous series with respect to duration of surgery, blood loss, hospital stay, complications, and functional outcome after 2 months, 12 months, and 60 months. It was found that staple technique significantly reduced the duration of surgery and the need of blood transfusions. Length of hospital stay after pouch surgery did not differ between the two groups, but omitting loop ileostomy reduced total hospital stay by about 2 weeks. Ileoanal anastomotic insufficiency occurred in two patients in the study group. Treatment by establishment of a defunctioning loop ileostomy, local saline perfusion, and administration of antibiotics was successful; the anastomosis healed within 2 weeks, and the longterm functional outcome did not differ from the average. Increased temperature persisted postoperatively in seven patients in the study group. Transient peroneal paresis occurred in three patients in the control group. Only in the control group was there stenosis in the ileoanal anastomosis requiring dilatation and fibrosis at the levator plane demanding emptying by a catheter. Concerning functional outcome, nighttime continence was significantly better in the study group than in the control group. The evacuation rate per 24 h was significantly higher in the study group after 2 and 12 months but not after 60 months. The outcome concerning other functional parameters such as urgency to evacuate, capacity to discriminate between gas and stool, deferral time, and perianal symptoms, did not differ significantly. Staple technique without mucosal proctectomy and loop ileostomy thus results in shorter duration of surgery and shorter hospital stay. In patients with increased risk of insufficiency of the anastomosis, however, covering loop ileostomy may be justified because of the risk for more serious consequences if anastomotic leakage occurs.

Optimal control of pull manufacturing systems

We consider the problem of optimal control of pull manufacturing systems. We study a fluid model of a flow shop, with buffer holding costs nondecreasing along the route. The system is subject to a constant exogenous demand, thus incurring additional shortfall/inventory costs. The objective is to determine the optimal control for the production rate at each machine in the system. We exhibit a decomposition of the flow shop into sections of contiguous machines, where, in each section, the head machine is the bottleneck for the downstream system. We exhibit the form of an optimal control and show that it is characterized by a set of times, one for each head machine. Machines which are upstream of a head machine simply adopt a just-in-time production policy. The head machines initially stay idle for a period equal to their deferral time and thereafter produce as fast as possible, until the initial shortfall is eliminated. The optimal values of these deferral times are simply obtained by solving a set of quadratic programming problems. We also exhibit special cases of re-entrant lines, for which the optimal control is similarly computable.

Alterations in ileoanal pouch technique, 1980 to 1987

This study presents the results of 82 ileoanal pouch operations (57 S, 25 J) performed from 1980 to 1987. It also reports the development of the operative technique during these years. The functional outcome was evaluated in 66 patients followed for 2 to 84 months (mean, 23). The mean number of bowel movements per 24 hours was 5.0. Seventy-four percent of the patients had no leakage or staining and 82 percent had a deferral time of more than one hour. Nightly evacuations were significantly more common in men than in women. Leakage and short deferral time were significantly more common in patients over 40 years of age than in those under 25. Early experience with the S-pouch was encumbered by evacuation problems and ileoanal separations. Shortening of the efferent conduits and the muscle cuffs reduced these complications significantly. Postoperative continence was improved significantly after reduction of anal dilatation and preservation of the transitional zone. The length of bowel used for the double-loop reservoirs seemed to be of importance concerning frequency.