Present-day Management Research Articles

Modeling as a tool to manage ecosystems under multiple stresses: an application to Lake Ontario

Present-day ecosystem management involves understanding of the synergistic effect of multiple stressors on multiple and frequently nebulous management end-points. An example is the simultaneous management of nutrient load reductions and salmon stocking in Lake Ontario. In this study, a simple whole-lake annual time scale model was developed to assess the relationship between these two stressors and various ecosystem responses. The model was used to explore the utility of some possible management end-points for ecosystem health. In historical simulations, production per stocked fish and salmon survival appeared to be good indicators, while nutrient recycling rate and average ecosystem-wide food limitation were found to be fairly unresponsive to the two stressors. The model was further used to predict long term averages of salmon biomass and selected health indicators at various sustained loading and stocking rates. Salmon biomass increased with stocking rate at all stocking rates examined, but the rate of increase declined somewhat at high stocking rates. The response of salmon biomass to nutrient loading appeared to be approximately sigmoidal i.e. there was a nutrient threshold below which fish biomass could not be sustained and another nutrient threshold above which salmon biomass either remained constant or even decreased. The response to either stressor was found to be modified by the value of the other stressor, illustrating the importance of ecosystem-level models for aquatic ecosystem management.

Management outcome in third ventricular colloid cysts in a defined population: a series of 40 patients treated mainly by transcallosal microsurgery.

Third ventricular colloid cysts account for 0.5% - 1.5% of all intracranial tumors. A thorough search of the world literature since 1858 revealed 1167 cases, for which a more than one-third (36%) management mortality was estimated. One third of the reported cases had modern diagnostics and surgery with minimal morbidity and nearly no mortality. The primary goal of this study was to assess the incidence and present-day management outcome of these lesions in the strictly defined area of Eastern Finland. In a series of 2000 patients with brain tumors from our catchment area (870,000 inhabitants in eastern Finland) during a 14.5-year period (years 1980-1994), 40 patients (mean age, 45 years; range, 19-75 years, with 21 females) had a third ventricular colloid cyst. Thirty-one patients had transcallosal extirpation of their cysts. One additional tumor was extirpated by the infratentorial supracerebellar route to include simultaneous biopsy of a tectal tumor (lipoma). One elderly male with severe cardiac disease received a ventriculoatrial shunt. Five patients, admitted deeply unconscious, died. In two of these five patients, desperate shunting operations were done, but, in the remaining three moribund patients, no treatment was considered to be of any benefit. Two patients with small tumors are being followed up. The far lateral transcallosal transforaminal extirpation of the cyst has served our patients well. There was no surgical mortality. The outcome was excellent in 30 patients and good in 3 patients. Follow-up time ranged from 2 months to 14.5 years (mean, 4.3 years). There were no tumor recurrences. Despite good surgical results, management mortality was as high as 13%, The incidence of third ventricular colloid cysts is at least 3.2/1 million/1 year. Even nowadays, up to one fifth of these completely benign and treatable tumors are detected too late, with calamitous consequences.

Nitrogen and Phosphorus Availability and the Role of Fire in Heathlands at Wilsons Promontory

Analyses of carbon, nitrogen and phosphorus in heathland soils at Wilsons Promontory and on Snake Island show that the effects of fire, including repeated fires, are confined to the surface 2 cm. The uppermost soil in long-unburnt heathlands is rich in these elements and usually has a smaller C:N ratio compared with the soil below. Indices of N and P availability (C:N ratios, concentrations of potentially mineralisable N and extractable inorganic P, phosphatase activity) are similar to those in highly productive eucalypt forests-a finding in conflict with past assessments of nutrient availability in heathlands. Phosphatase activity and concentrations of carbon, nitrogen and potentially mineralisable N were less in soils from repeatedly burnt heathlands than in soils from long unburnt heathlands whereas there was a greater concentration of extractable inorganic P in soils from repeatedly burnt heathlands. The balance between nitrogen input and loss is dependent on fire frequency and present-day management of heathland (and other native plant communities with low nutrient capitals) should recognise that over- or under-use of fire will significantly alter soil nutrient pools and availability and that these changes may alter community species composition and productivity.

Managing for Quality in the US and in Japan

What are the Japanese doing that causes so many of their products to be of extremely high quality? Is their ability to produce high-quality items a cultural phenomenon or can it be imported to the US? This survey of the current literature on managing for quality begins with a historic overview and examines Japanese quality practices. These concepts have been extended to present-day management, information flows, product design, purchasing, and manufacturing in both Japan and the United States. They form an integrated approach to using manufacturing to attain a competitive advantage, an approach that uses quality management as an important component and emphasizes the linkages among components and functions within an organization.

Los bancales en la agricultura de la montaña mediterránea: una revisión bibliográfica

The most common subjects in the literature on agricultural terraces are reviewed, their temporal and spatial origin, classification, the traditional and present-day management of the terraced slopes and the geomorphological evolution of them both during the working and after the abandonment.

Lifetime performance of sows given different rearing and pregnancy feeding regimes

Greater demands have been Imposed by present-day management practices on the modern dam with gilts being bred at younger ages and lower levels of back fat. This has raised questions over whether current rearing feeding practices and low pregnancy feeding regimes may have adverse Influences on lifetime reproductive performance. The objectives of this experiment were to compare the reproductive performance of sows given different feeding regimes during rearing and pregnancy. Data previously reported from the experiment have shown that the weight and back fat depth of the gilt and sow can be manipulated by feeding regime over the first four parities (Simmins et al. 1989, 1991). Sows reared on the lower feed levels were more prolific 1n their first two Utters, but also had longer, farrowing Intervals (Edwards et al. 1989). These sows remained more prolific by weaning of the fourth Utter (Simmins et al. 1991). Performance over eight litters is described below.

Effect of feeding regime during rearing and subsequent pregnancies on body conditions and reproductive performance of sows over the first four parities

Greater demands have been imposed by present-day management practices on the modern dam with gilts being bred at younger ages and lower levels of back fat. This has raised questions over whether current rearing feeding practices and low pregnancy feeding regimes may have adverse influences on lifetime reproductive performance. The objectives of this experiment were to compare the reproductive performance of sows given different feeding regimes during rearing and pregnancy. Data previously reported from the experiment have shown that the weight and back fat depth of the gilt can be manipulated by feeding regime during rearing and pregnancy (Simmins et al. 1989). Sows reared on lower feed levels were more prolific in their first two litters but they also had longer farrowing intervals (Edwards et al. 1989). Further results up to the fourth parity are described here.

Great ideas in management: lessons from the founders and foundations of managerial practice

Provides current and prospective managers with the classical foundations of management thought. Draws on the studies of Taylor, Skinner, and others to uncover diverse ways to motivate and lead employees. Spells out the lessons that can be applied to present-day management problems and situations.

The Modernization of the Frederikshavn Shipyard

This paper outlines the development of the Frederikshavn Shipyard, Denmark, from the building of wooden fishing vessels in 1870 to the construction of modern coasters and roll-on, roll-off carriers. It goes on to give details of the comprehensive modernization scheme carried out in recent years and discusses the problems of installing a completely integrated data processing system in a modern shipyard. The paper concludes by describing the reorganization of the staff structure and the present-day management philosophy of the company.

Ecological Adaptation of Traditional Land Uses in the Spanish Pyrenees

A review of research completed in several disciplines, including ecology and anthropology, in the Spanish Pyrenees shows that the traditional society formed an open system, with wide cultural and economic interactions with the surrounding lowlands. The management of three main resources, forests, grain crops, and meadows, and their space allocation in the mountain landscape show that rural life depended upon a close interrelationship of cereal production and sheep breeding and was strongly controlled by local environmental features. The traditional structure has been disrupted by the impact of urban culture; its preservation must be considered as one of the main challenges in present-day management issues of temperate mountain regions.

Anthracycline cardiomyopathy.

Life-threatening irreversible cardiomyopathy is a major complication of anthracycline therapy, particularly in the pediatric population. The pediatric cardiologist, in concert with the primary oncologist, should therefore play a major role in the care of patients receiving these agents and in clinical trials involving their use. Many risk factors and their relationships to drug pharmacokinetics, mechanisms of action, and toxicity have been identified. These data provide a rational basis for present-day recommendations regarding anthracycline administration and dosage scheduling. They furthermore provide potential avenues for clinical investigation aimed at improving the therapeutic index of these agents: alpha-tocopherol, cytochrome Q10, and other free radical scavengers may decrease the deleterious effects of free radical generation on the myocardium without apparent interference with tumoricidal effect. The cardiac glycosides may decrease cardiac toxicity by specific myocardial exclusion. Anthracycline analogs have been designed to specifically inhibit myocardial binding and/or free radical generation. Clinical trials involving these agents are difficult to interpret because of variability in front end risk factors and dosage schedules in the study population. Furthermore, the relatively low (5 to 10%) incidence of affected patients implies the need for large numbers to demonstrate a statistically significant benefit. Pediatric protocols addressing these issues are urgently needed. Guidelines for present-day management and future studies are outlined.

Cancer of the Oral Cavity

The principles of head and neck surgery have continued to evolve in recent years, but the young head and neck surgeon may struggle in a sea of conflicting viewpoints before finding the support these principles can give. A review of the Mayo Clinic experience over a recent 20-year period and a delineation of those principles leading to our present-day management of intraoral cancer are presented.

Mechanical Support of Respiration

Advancing technology and accumulating knowledge of physiologic processes have combined, during the last decade, to bring mechanical ventilatory assistance to a high degree of perfection. It is most instructive, however, to trace the historical development and application of these concepts in order to understand present-day respiratory management.

The natural history of hypertension with moderate impairment of renal function.

1. A continuing prospective study of patients with severe hypertension is now in its eighteenth year. 2. Patients with impaired renal function survive longer with present-day management if control of pressure is good and if renal structural abnormalities are not gross. 3. Since 1960 myocardial infarction, rather than cerebrovascular accident, has been the commonest cause of death.

Present-Day Management of Acute Myocardial Infarction

Present-Day Management of Acute Myocardial Infarction

Placing the Management of Defense and Space Programs in Perspective

The author assesses the management of defense and space programs. He describes the contractual environment leading to development of the present-day management systems and gives attention to (a) management system criteria, (b) the nature of program management, (c) organizational structures for managing programs, and (d) problems and benefits attributable to management approaches used.

Pollution problems, resource policy, and the scientist.

Through exponential increase in population, accompanied by rapid industrial and agricultural expansion, we have reached the point where decisions involving the use of natural resources are much more important and also much more difficult than they were even 10 years ago. The same conditions that make decisions more urgent make them more time-consuming. The Cayuga Lake case illustrates many aspects of a present-day resource management controversy.

Pleural Empyema in Children

n the late 1950’s a tremendous increase in the incidence of staphylococcal pneumonia and empyema occurred throughout many of the I pediatric centers in the country. This increase was thought to have been caused by the emergence of antibiotic-resistant strains of bacteria [3]. Several papers appeared in the literature reflecting this changing pattern [4, 6, 71, and some strict rules for surgical management were advised in order to decrease mortality in this disease [6]. Formerly, this mortality ranged from a high of 100% in some series [l] to about 25% in other centers [5, 61. The generally accepted surgical routine was to insert a chest tube in all children who exhibited pleural fluid containing gram-positive cocci. This was followed frequently by conversion to open drainage with or without rib resection, and finally decortication if there was no definite improvement in two or three weeks and a captive lung was assumed to be present. Strict adherence to these principles brought the mortality down to around 10 or 12% [6]. Since about 1962, pleural empyema in children, particularly that due to staphylococci, has become less virulent, probably entirely as the result of newer antibiotic agents. Now certain transgressions can be taken from the older rules of management in order to shorten the hospital stay and decrease the discomfort of these children. It is the purpose of this paper to review the experience with all children diagnosed as having primary pneumonia and secondary empyema over the past 20 years at the Children’s Hospital of Los Angeles, in order to compare present-day management with that practiced 10 years ago.

Treatment of bacterial endocarditis in patients with penicillin hypersensitivity.

Excerpt A major problem in present-day management of bacterial endocarditis is the choice of optimal antibiotic therapy in patients who give a history of allergy to penicillin. Bacterial endocardit...

PRESENT-DAY MANAGEMENT OF GASTRIC CANCER.

It is doubtful that total gastrectomy or extended total gastrectomy will do much to increase the cure rate of gastric cancer. Earlier recognition and earlier operation are the only means by which resectability and curability rates can be improved. When a tumor has developed to the stage where a very radical procedure must be done, operative mortality rises and the cure rate falls.