Proactive interference and the dynamics of free recall.

Proactive interference (PI) has long been recognized as a major cause of forgetting. Two experiments were conducted that offer another look at the subject by providing a detailed analysis of recall latency distributions during the buildup of and release from PI. These functions were accurately characterized by the convolution of the normal and exponential distributions (viz., the ex-Gaussian), which previously has been shown to describe recognition latency distributions. Further, the fits revealed that the increase in recall latency associated with the buildup of PI results from a slowing of the exponential retrieval stage only. The same result was found even when a short retention interval was used (and recall probability remained constant). These findings suggest that free-recall latency may be a sensitive index of the increased search set size that has often been assumed to accompany the buildup of PI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recognition and Importance of Restrictions on Randomization in Industrial Experimentation

Statisticians typically recommend completely randomized experimental designs. The reasoning behind this advice is theoretically sound. Unfortunately, engineers who typically run industrial experiments frequently fail to recognize restrictions on randomization, i.e., split-plot experiments, and are often unaware of the risks associated with analyzing split-plot experiments as if they were randomized. Similarly, issues concerning the inference space of the experiment frequently are not given adequate consideration. Conversely, statisticians frequently are unaware that a restriction on randomization does not necessarily translate into less information than a completely randomized design.

In this paper, we discuss a proactive methodology for identifying and incorporating information concerning restrictions on randomization and inference space in industrial experiments. We also present the factor relationship diagram (FRD), a tool that assists engineers in the recognition of restrictions of randomization and guides the development of questions that encourage the experimenter to understand those sources of variation that may contribute to a lack of precision in a split-plot experiment or lack of repeatability in inference space different from that studied in the experiment. Examples that illustrate the use of the methodology and the FRD are included.     

Preventive medicine: costs and responsibilities of insurance companies

Under the provisions of the Health Insurance Law (KVG), the costs of preventive medicine are to be borne by the mandatory health insurance. Although it has been defined who shall be responsible for taking the necessary measures, concrete objectives have yet to be established. This is giving rise to difficulties in the implementation of the law. The author discusses basic questions relating to this situation: The nature of the preventive measures (GENOME Analysis), and the economic efficiency. An insight is also given into the work of the Preventive Medicine Services Subcommittee of the Federal Service-Providing Committee (Subkommission Pr?ventive Leistungen der Eidgen?ssischen Leistungskommission) and the criteria adopted.     

Computer analysis of a polymer coating exposed to field weather conditions

A heat and moisture transfer model was used to study weathering of polymeric materials, such as paint, asphalt, sealants, plastics, textiles, and polymeric composites. Three damage indices, related to temperature changes, humidity changes, and time of wetness, respectively, were introduced to quantify adverse effects of climate. The variation of these indices was investigated for a hot and humid climate (Miami, FL) and a hot and dry climate (Phoenix, AZ). In addition, the relative effects of solar radiation, surface wetting by rain and dew condensation, and variations in outdoor temperature and relative humidity on the three damage indices were investigated. 100 Bureau Dr., Stop 8621, Gaithersburg, MD 20899-8621.     

Pathophysiology of dehydration

The pathophysiology of dehydration is reviewed. The normal response to dehydration, i.e. decreased effective arterial blood volume or effective circulating volume is described. Due to water retention and drinking following stimulation of ADH secretion and thirst, osmoregulation is overruled by volume conservatory mechanisms, which lead to hyponatremia. Only patients with impaired mental function or those who are unable to drink will develop a progressive water deficit--with or without salt depletion--recognizable by hypernatremia. Decreased effective arterial blood volume and hypernatremia affect cerebral function in a way that perception of external stimuli as well as perception of pain will be impaired. Alert dehydrated patients are disturbed mainly by thirst and dryness of the mouth. Both symptoms are perceived more intensely by young than by elderly persons. Dryness of the mouth increase thirst on its own. Distress by thirst and oral dryness increases as a function of the level and the rapidity of developing hypernatremia. The simple act of filling the oral cavity with fluid and swallowing alleviates thirst in the absence of any change in plasma sodium concentration. Thirst quenching efficacy is increased by administering chilled hypotonic fluid with lemon or other fruit acid added (for stimulation of salivation).     

Interstitial methotrexate kinetics in primary breast cancer lesions

The transfer of cytotoxic agents across the tumor endothelium into the interstitial tumor space is considered a critical step in clinical resistance of solid tumors to antineoplastic chemotherapy. However, experimental data on drug transfer from the blood into the interstitium of solid tumors are scarce. Therefore, in this study, we used an innovative technique, in vivo microdialysis, for measuring interstitial tumor pharmacokinetics and plasma-to-tumor transfer rates of methotrexate (MTX) in breast cancer patients. Microdialysis probes were inserted into the primary tumor and the periumbilical s.c. adipose layer of nine previously chemotherapy-naive breast cancer patients to monitor interstitial concentrations following i.v. administration of MTX (40 mg/m2) during a three-drug treatment regimen. Mean interstitial MTX load in breast tumors, expressed as area under curve (AUC), was 60 +/- 20% (mean +/- SE; coefficient of variation = 100%) of mean plasma MTX load. There was no correlation between plasma AUC and the AUC in the interstitial space of tumor tissue (P = 0.93). Not one of the parameters plasma, interstitial tumor load, and transfer rate of MTX to the interstitial space was associated with favorable clinical response. In conclusion, plasma levels of MTX are not predictive of intratumor levels. There is a high interindividual variability in transendothelial MTX transfer. Under the present conditions, access of MTX to the interstitial space is not a rate-limiting step for clinical response to chemotherapy.     

Graft patency and saving the extremity as a function of asymptomatic/symptomatic aneurysm of the popliteal artery and the graft material used

A 27-year experience with 252 popliteal artery aneurysms in 167 patients is reviewed. Long-term results with respect to graft patency and limb salvage rates are analyzed. The results emphasize the importance of early surgical intervention and demonstrate the superiority of autologous saphenous vein over other graft materials.