"Homeward bound": a minimal care rehabilitation unit.

A 20 bed minimal care rehabilitation unit was set up by Newham District Health Authority in a small hospital originally scheduled for closure when a new district general hospital was opened. During the first year 114 patients were admitted (throughput 5.7), with a median length of stay of 30 days; in the second year 173 patients were admitted (throughput 8.65) with a median length of stay of 28.5 days. The cost per inpatient day was less than that of an inpatient day at the district''s long stay geriatric unit. Before the unit opened 24% of the acute beds had been occupied for more than six weeks, whereas two years later only 6% of the acute beds were occupied for such a period.     

Variation in rates of hospital admission for appendicitis in Wales.

In a study designed to investigate the variations in rates of admission to hospital for appendicitis in Wales Hospital Activity Analysis listings were analysed according to the sex and age of the patients and the month and day of the week of admission. The incidence of hospitalisation was greatest among boys aged 10-14 and girls aged 15-19. The number of admissions was higher on weekdays than at weekends, but there were no seasonal variations. Durations of stay differed between the 17 health districts. We conclude that admission rates vary mainly because of differing hospital admission policies. Admission is not wholly governed by the sudden onset of abdominal pain; other factors include the threshold of consultation of each patient, the referral habits of general practitioners, the availability of hospital beds, and the degree to which doctors and patients expect admission.     

Incidence Rate of Needlestick and Sharps Injuries in 67 Japanese Hospitals: A National Surveillance Study

Background

Determining incidence rates of needlestick and sharps injuries (NSIs) using data from multiple hospitals may help hospitals to compare their in-house data with national averages and thereby institute relevant measures to minimize NSIs. We aimed to determine the incidence rate of NSIs using the nationwide EPINet surveillance system.

Methodology/Principal Findings

Data were analyzed from 5,463 cases collected between April 2009 and March 2011 from 67 Japanese HIV/AIDS referral hospitals that participated in EPINet-Japan. The NSI incidence rate was calculated as the annual number of cases with NSIs per 100 occupied beds, according to the demographic characteristics of the injured person, place, timing, device, and the patients’ infectious status. The NSI incidence rates according to hospital size were analyzed by a non-parametric test of trend. The mean number of cases with NSIs per 100 occupied beds per year was 4.8 (95% confidence interval, 4.1–5.6) for 25 hospitals with 399 or fewer beds, 6.7 (5.9–7.4) for 24 hospitals with 400–799 beds, and 7.6 (6.7–8.5) for 18 hospitals with 800 or more beds (p-trend<0.01). NSIs frequently occurred in health care workers in their 20 s; the NSI incidence rate for this age group was 2.1 (1.6–2.5) for hospitals having 399 or fewer beds, 3.5 (3.0–4.1) for hospitals with 400–799 beds, and 4.5 (3.9–5.0) for hospitals with 800 or more beds (p-trend<0.01).

Conclusions/Significance

The incidence rate of NSIs tended to be higher for larger hospitals and in workers aged less than 40 years; injury occurrence was more likely to occur in places such as patient rooms and operating rooms. Application of the NSI incidence rates by hospital size, as a benchmark, could allow individual hospitals to compare their NSI incidence rates with those of other institutions, which could facilitate the development of adequate control strategies.     

Modeling and optimal control of insect pest populations

A distributed-parameter population dynamics model is developed specifically for use with variational optimization techniques. The objective is to develop a modeling/ optimization technique that will permit the development of optimal control policies which minimize combined costs of pest control and economic-yield loss. The model results and optimal control policies are continuous and distributed in time and in insect age. The technique is applied to a study of control by pesticide of the southern green stink bug, Nezara viridula (Linnaeus), a major pest of soybeans in the South. In this case study, the model results agree well with field-survey results, while the optimal control trajectories are reasonable and suggest several avenues for further study.     

Use of hospital beds: a cohort study of admissions to a provincial teaching hospital.

An instrument was developed to study the use of hospital beds and discharge arrangements of a cohort of 847 admissions to the John Radcliffe Hospital, Oxford, for a three week period during February-March 1986. For only 38% of bed days were patients considered to have medical, nursing, or life support reasons for requiring a provincial teaching hospital bed. The requirements for a bed in the hospital decreased with the patient''s age and length of stay in hospital. For only a tenth of patients was the general practitioner concerned in discussions with hospital staff about the patient''s discharge and less than one third of patients had been given more than 24 hours'' notice of discharge. Several features might increase the proportion of bed days that are occupied by patients with positive reasons for being in hospital. Among these are an increased frequency of ward rounds by consultants, or delegating discharge decisions by consultants to other staff; providing diagnostic related protocols for planning the length of stay in hospital; planned discharges; and providing liaison nurses to help with communication with primary care staff.     

基于灰熵关联的平均住院日影响因素研究

目的:分析医疗指标与平均住院日的关联程度,为医院有效缩短平均住院日提供参考依据。方法:建立基于灰熵优化的加权灰色关联度模型,对影响平均住院日的医疗指标进行重要程度的分析。结果:根据关联程度分析,可知影响平均住院日的医疗指标重要程度依次为开放床位数、床位周转次数、治疗有效率、床位使用率、年门诊量、住院手术人次和出院人数。结论:基于灰熵优化的加权灰色关联分析方法可以有效分析医疗指标对平均住院日的影响程度,提高医疗服务质量。     

First seven years of a new NHS mental handicap service 1974-81.

A new community-focused mental handicap service was started in a single-district area health authority in 1974. Almost 90% of all the severely mentally handicapped people in a population of 250,000 are now known to the service. Although two-thirds of long stay inpatients originally admitted with major behavioural problems have had them resolved, the remaining one-third with persisting problems are noted to have spent many years in large understaffed wards before transfer. Specialist services to mentally handicapped people are not synonymous with beds. The learning opportunities during the waking hours of a mentally handicapped person are where professional help must be concentrated, and extensive support services for those caring for the mentally handicapped at home must be set up. Absence of shared philosophies, policies, and planning among the health and local authorities has produced the problems and frustrations familiar to many professionals in mental handicap. Future developments must be based on clearly defined and declared principles.     

Simulated annealing with different vessel assignment strategies for the continuous berth allocation problem

The berth allocation problem is an optimization problem concerning seaside operations at container terminals. This study investigates the dynamic and continuous berth allocation problem (BAP), whose objective is to minimize the total weighted service time and the deviation cost from vessels’ preferred position. The problem is formulated as a mixed integer programming model. Due to that the BAP is NP-hard, two efficient and effective simulated annealing (SA) algorithms are proposed to locate vessels along the quay. The first SA assigns vessels to available positions along the quay from the left to the right, while the second assigns vessels from both sides. Both small and large-scale instances in the literature are tested to evaluate the effectiveness of the proposed SA algorithms using the optimization software Gurobi and heuristic algorithms from the literature. The results indicate that the proposed SAs can provide optimal solutions in small-scale instances and updates the best solutions in large-scale instances. The improvement over other comparing heuristics is statistically significant.     

Increasing Short-Stay Unplanned Hospital Admissions among Children in England; Time Trends Analysis ’97–‘06

Background

Timely care by general practitioners in the community keeps children out of hospital and provides better continuity of care. Yet in the UK, access to primary care has diminished since 2004 when changes in general practitioners'' contracts enabled them to ‘opt out’ of providing out-of-hours care and since then unplanned pediatric hospital admission rates have escalated, particularly through emergency departments. We hypothesised that any increase in isolated short stay admissions for childhood illness might reflect failure to manage these cases in the community over a 10 year period spanning these changes.

Methods and Findings

We conducted a population based time trends study of major causes of hospital admission in children <10 years using the Hospital Episode Statistics database, which records all admissions to all NHS hospitals in England using ICD10 codes. Outcomes measures were total and isolated short stay unplanned hospital admissions (lasting less than 2 days without readmission within 28 days) from 1997 to 2006. Over the period annual unplanned admission rates in children aged <10 years rose by 22% (from 73.6/1000 to 89.5/1000 child years) with larger increases of 41% in isolated short stay admissions (from 42.7/1000 to 60.2/1000 child years). There was a smaller fall of 12% in admissions with length of stay of >2 days. By 2006, 67.3% of all unplanned admissions were isolated short stays <2 days. The increases in admission rates were greater for common non-infectious than infectious causes of admissions.

Conclusions

Short stay unplanned hospital admission rates in young children in England have increased substantially in recent years and are not accounted for by reductions in length of in-hospital stay. The majority are isolated short stay admissions for minor illness episodes that could be better managed by primary care in the community and may be evidence of a failure of primary care services.     

Immunonutrition for patients undergoing elective surgery for gastrointestinal cancer: impact on hospital costs

ABSTRACT: BACKGROUND: Oral or enteral dietary supplementation with arginine, omega 3 fatty acids and nucleotides (known as immunonutrition) significantly improve outcomes in patients undergoing elective surgery. The objective of the study was to determine the impact on hospital costs of immunonutrition formulas used in patients undergoing elective surgery for gastrointestinal cancer. METHODS: US hospital costs of stay with and without surgical infectious complications, and average cost per day in the hospital for patients undergoing elective surgery for gastrointestinal cancer were estimated using data from the Healthcare Cost and Utilization Project's 2008 Nationwide Inpatient Sample. These costs were then used to estimate the impact of perioperative immunonutrition on hospital costs using estimates of reduction in infectious complications or length of stay from a meta-analysis of clinical trials in patients undergoing elective surgery for gastrointestinal cancer. Sensitivity of the results to changes in baseline complication rates or length of stay was tested. RESULTS: From the meta-analysis estimates, use of immunonutrition resulted in savings per patient of $3,300 with costs based on reduction in infectious complication rates or $6,000 with costs based on length of hospital stay. Cost savings per patient were present for baseline complication rates above 3.5% or when baseline length of stay and infectious complication rates were reduced to reflect recent US data for those with upper and lower GI elective cancer surgery (range, $1,200 to $6,300). CONCLUSIONS: Use of immunonutrition for patients undergoing elective surgery for gastrointestinal cancer is an effective and cost-saving intervention.     

上海市医疗机构床位配置调整策略研究

目的 分析上海市医疗机构床位资源配置的现状和问题。方法 采用调查问卷对上海市所有设住院床位的医疗机构进行调查,并与美国加利福尼亚州医疗机构床位情况进行对比。结果 床位总量接近规划但配置结构不合理,综合急性病诊疗床位的平均住院时间过长,医疗服务压力主要集中在三级医疗机构,社会办医疗机构病床尚没有得到有效利用。结论 建立医疗机构床位分类管理制度,严格控制中心城区三级医疗机构床位数量,严格控制综合急性病诊疗床位,大幅增加护理床位数量,有效整合医疗床位资源。     

Bioprocess iterative batch-to-batch optimization based on hybrid parametric/nonparametric models

This paper presents a novel method for iterative batch-to-batch dynamic optimization of bioprocesses. The relationship between process performance and control inputs is established by means of hybrid grey-box models combining parametric and nonparametric structures. The bioreactor dynamics are defined by material balance equations, whereas the cell population subsystem is represented by an adjustable mixture of nonparametric and parametric models. Thus optimizations are possible without detailed mechanistic knowledge concerning the biological system. A clustering technique is used to supervise the reliability of the nonparametric subsystem during the optimization. Whenever the nonparametric outputs are unreliable, the objective function is penalized. The technique was evaluated with three simulation case studies. The overall results suggest that the convergence to the optimal process performance may be achieved after a small number of batches. The model unreliability risk constraint along with sampling scheduling are crucial to minimize the experimental effort required to attain a given process performance. In general terms, it may be concluded that the proposed method broadens the application of the hybrid parametric/nonparametric modeling technique to "newer" processes with higher potential for optimization.     

Endoscopically assisted "components separation" for closure of abdominal wall defects

The repair of ventral hernia defects of the abdominal wall challenges both general and plastic surgeons. Ventral herniation is a postoperative complication in 10 percent of abdominal surgeries; the repair of such defects has a recurrence rate as high as 50 percent. The "components separation" technique has successfully decreased the recurrence rates of ventral abdominal hernias. However, this technique has been associated with midline dehiscence and a prolonged postoperative stay at the authors' institutions. The purpose of this study was to determine whether endoscopically assisted components separation could minimize operative damage to the vasculature of the abdominal wall and decrease postoperative wound dehiscence. The study group consisted of seven patients who underwent endoscopically assisted components separation; the control group consisted of 30 patients who underwent open components separation. The two groups were similar regarding demographic data and defect size. The endoscopic group had a higher initial success rate than the open group (100 versus 77 percent). Recurrence rates were not significantly different between the two groups. However, the endoscopically assisted components separation patients had fewer postoperative and long-term complications. In the authors' experience, endoscopically assisted components separation has proved to be a safe and effective method for the repair of complicated and recurrent midline ventral hernias.     

Regional survey of femoral neck fractures.

In the South-west Thames Region 2619 patients (2105 women and 514 men) were discharged with a diagnosis of femoral neck fracture in 1974. The equivalent of a 250-bedded hospital was occupied throughout the year. The incidence, average length of stay, and mortality rate rose with increasing age and there were differences in these indices in the five health areas. These results confirm the enormous burden placed on the hospital service by patients with fracture of the femoral neck but suggest that differences in practice in the five areas may contribute to the size of the problem.     

Optimal dispatching of multipriority jobs to two heterogeneous workstations

The general problem scenario of this paper is the following: Jobs of various priorities, stationed in a common storage area, are waiting to be dispatched to two non-identical workstations. Any of the waiting jobs can be accessed from the storage at any given time. Each job can be processed on either of the workstations, but once a job has been assigned it may not be preempted. By job priority it is meant that a higher priority job has disptach preference over a lower priority job. The processing time of a job on a given workstation is assumed to be random, the distribution being dependent on the job type and the configuration of the workstation. Specifically, the first problem studied considers only two classes of jobs: (1) “hot” jobs, whose processing is to be expedited and thus have the higher dispatch priority, and (2) “routine” jobs which may be assigned to an available workstation only if the workstation has been rejected by all “hot” jobs. The processing times are assumed to be exponentially distributed with means depending on the job class and workstation. We assume that, on the average, one workstation is faster than the other with regard to processing any job. The dispatching objective for each job class is to minimize its expected flowtime. It is shown that threshold dispatching policies are optimal for this problem. That is, the faster processor should be utilized whenever possible, and for each class there exists an explicit threshold such that when the number of jobs of that class in the buffer exceeds this threshold then a job of that class is dispatched to the slower processor, otherwise these jobs wait for the faster processor to become available. For the higher priority jobs, this threshold is shown to be a function only of the various processing rates of the two workstations. For the lower priority jobs, the threshold also depends on the number of higher priority jobs in the buffer. The results is extended to a system with n priority classes. Again, it is shown that when the processing times are exponentially distributed with different rates and the dispatching objective for each class is to minimize its expected flowtime, the optimal dispatching policies are of threshold type. Explicit thresholds are easily derived.     

Feedback optimization of fed-batch fermentation

The problem of feedback optimization of the feed rate for fed-batch fermentation processes is formulated in the framework of singular control theory and switching hypersurfaces. Using four differential balance equations that describe a general class of fedbatch processes and a general objective function to be minimized, it is shown that under certain restrictions the feedback optimization of the feed rate can be realized as a nonlinear function of the state variables, such as the concentrations of cell mass, substrate and product, and the fermentor volume. The restrictions on the initial conditions, the fermentation kinetics and the objective function, that are needed for realization of the feedback optimization, are provided. Fed-batch fermentation models of lysine and alcohol are used to construct switching curves and to illustrate the feedback optimization of the feed flow rates.     

Multicriteria optimization of biochemical systems by linear programming: application to production of ethanol by Saccharomyces cerevisiae

In this study we present a method for simultaneous optimization of several metabolic responses of biochemical pathways. The method, based on the use of the power law formalism to obtain a linear system in logarithmic coordinates, is applied to ethanol production by Saccharomyces cerevisiae. Starting from an experimentally based kinetic model, we translated it to its power law equivalent. With this new model representation, we then applied the multiobjective optimization method. Our intent was to maximize ethanol production and minimize each of the internal metabolite concentrations. To ensure cell viability, all optimizations were carried out under imposed constraints. The different solutions obtained, which correspond to alternative patterns of enzyme overexpression, were implemented in the original model. We discovered few discrepancies between the S-system-optimized steady state and the corresponding optimized state in the original kinetic model, thus demonstrating the suitability of the S-system representation as the basis for the optimization procedure. In all optimized solutions, the ATP level reached its maximum and any increase in its activity positively affected the optimization process. This work illustrates that in any optimization study no single criteria is of general application being the multiobjective and constrained task the proper way to address it. It is concluded that the proposed multiobjective method can serve to carry out, in a single study, the general pattern of behavior of a given metabolic system with regard to its control and optimization.     

SPERM COMPETITION AND REPRODUCTIVE MODE INFLUENCE SPERM DIMENSIONS AND STRUCTURE AMONG SNAKES

The role of sperm competition in increasing sperm length is a controversial issue, because findings from different taxa seem contradictory. We present a comparative study of 25 species of snakes with different levels of sperm competition to test whether it influences the size and structure of different sperm components. We show that, as levels of sperm competition increase, so does sperm length, and that this elongation is largely explained by increases in midpiece length. In snakes, the midpiece is comparatively large and it contains structures, which in other taxa are present in the rest of the flagellum, suggesting that it may integrate some of its functions. Thus, increases in sperm midpiece size would result in more energy as well as greater propulsion force. Sperm competition also increases the area occupied by the fibrous sheath and outer dense fibers within the sperm midpiece, revealing for the first time an effect upon structural elements within the sperm. Finally, differences in male–male encounter rates between oviparous and viviparous species seem to lead to differences in levels of sperm competition. We conclude that the influence of sperm competition upon different sperm components varies between taxa, because their structure and function is different.     

HOPE: a homotopy optimization method for protein structure prediction.

We use a homotopy optimization method, HOPE, to minimize the potential energy associated with a protein model. The method uses the minimum energy conformation of one protein as a template to predict the lowest energy structure of a query sequence. This objective is achieved by following a path of conformations determined by a homotopy between the potential energy functions for the two proteins. Ensembles of solutions are produced by perturbing conformations along the path, increasing the likelihood of predicting correct structures. Successful results are presented for pairs of homologous proteins, where HOPE is compared to a variant of Newton's method and to simulated annealing.     

Comparing protein-ligand docking programs is difficult

There is currently great interest in comparing protein-ligand docking programs. A review of recent comparisons shows that it is difficult to draw conclusions of general applicability. Statistical hypothesis testing is required to ensure that differences in pose-prediction success rates and enrichment rates are significant. Numerical measures such as root-mean-square deviation need careful interpretation and may profitably be supplemented by interaction-based measures and visual inspection of dockings. Test sets must be of appropriate diversity and of good experimental reliability. The effects of crystal-packing interactions may be important. The method used for generating starting ligand geometries and positions may have an appreciable effect on docking results. For fair comparison, programs must be given search problems of equal complexity (e.g. binding-site regions of the same size) and approximately equal time in which to solve them. Comparisons based on rescoring require local optimization of the ligand in the space of the new objective function. Re-implementations of published scoring functions may give significantly different results from the originals. Ostensibly minor details in methodology may have a profound influence on headline success rates.