Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “range adaptation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 685 records · Page 38Linked to original sources
PubMed1980

Postoperative pain relief by demand analgesia.

Postoperative pain relief is only apparently an easy task. A brief survey of literature investigating the discomfort experienced in the postoperative phase is all but encouraging. One can identify four basic problems in obtaining adequate results by delivery of analgesic drugs: a) the biological variability among individual patients, b) the unpredictable uptake of the drug administered intramuscularly, c) the time lag involved between request by the patient and the subsequent administration of a single dose and d) the lack of knowledge about the nature of the discomfort and its remedies. An alternative strategy introducing "On-Demand" analgesia administering prescribed doses at the right moment is presented and analysed a) as an operant conditioning process implementing a particular reinforcement schedule (behavioural sciences), as well as b) a negative feedback control loop that entrust the central judgement to the patient (system theory). Both approaches give insight into the results: the technique copes with biological variability; anticipating pain induced by fear disappears; the feedback strategy works well and patients adapt to a wide range in prescriptions; intermittent administration makes more efficient use of the analgesic; an optimal result is demonstrated in studies comparing on-demand analgesia with the normal IM-regime and epidural analgesia; continuity in pain relief can be obtained in routine clinical practice.

Analgesics↗
PubMed1993

Stabilization ponds in the tropics: promotion of the sanitary reuse of water.

This article reports the results of efforts by PAHO's Environmental Health Program to lay the groundwork for designing wastewater stabilization ponds suited to tropical areas. The resulting design concepts are flexible (permitting pond construction to be adapted to a broad range of terrains, community sizes, and working temperatures) and directed at meeting WHO standards established for the microbial quality of effluents used in agriculture and aquaculture. The WHO standards (1) call for treated wastewater being used in agriculture or aquaculture to contain less than 1,000 fecal coliforms per 100 ml. The plans outlined here, which are calculated to meet those standards, seek to minimize the pond area and volume needed by using two high-load primary anaerobic ponds discharging into an elongated secondary pond with a length-to-width ratio of at least 15:1. In rough terrain the elongated pond can be allowed to meander, following the land's natural contours. However, where the terrain is level it is recommended that a system of partitions be used to maintain the 15:1 ratio for operating purposes while changing the actual ratio of the secondary pond's outer dimensions to something like 5:3. Basic equations presented in the text will be helpful in estimating the pond sizes needed to cope with different climatic conditions, community sizes, per capita rates of wastewater generation, and per capita biochemical oxygen demands. While these equations should prove of great assistance during initial planning and development of preliminary criteria, nothing in this article supplants the topographic and geotechnologic studies that will be needed in order to clearly determine what is feasible in any given case.

Agriculture↗
PubMed1977

Retina viability in the Necturus.

Electroretinograms (ERG's) were recorded from the eyes of paralyzed normal and decapitated mudpuppies (Necturus maculosus). Fully dark-adapted responses to a range of stimulus intensities were compiled hourly under both conditions. Statistical analyses indicate no significant change in responsiveness in paralyzed normal animals during periods up to 6 hours. After decapitation, there was a significant decline of sensitivity to light during the first 3 hours. An oxygen-sensitive component similar to the c-wave was observed with DC recording but only in normal eyes. Anoxic mudpuppy eyes show an ERG decline with an average time constant of 1.5 hours.

Animals↗
PubMed1996

Approaches to venous leg ulcer care within the community: compression, pinch skin grafts and simple venous surgery.

The traditional approach to leg ulcer care is both expensive and achieves poor outcomes. The outcome of treatment for patients with venous ulceration has been improved using a more scientific and research-based approach to patient assessment, adequate compression bandaging, use of other procedures such as pinch skin grafting and simple venous surgery, and the delivery of these innovations in patient care to the community as a whole. Multi-layer compression bandaging is superior to standard (one-layer) bandaging because it can easily be adapted to a wide range of ankle circumferences and leg sizes to provide sustained, graduated compression. Pinch skin grafting is cost-effective, accelerates healing, and, following adequate training, may be performed by specialist nurses in the community. Simple venous surgery may be offered under local anaesthesia when only the superficial veins are incompetent; however, deep venous surgery has yet to prove itself in clinical practice. Implementation of dedicated community leg ulcer clinics using these research-based findings will result in a substantially reduced prevalence of venous leg ulceration.

Ambulatory Care↗
PubMed1996

[The regulatory properties of the enzymes of the digestive glands].

An adaptation of the enzyme range of the pancreatic secret to composition and properties of the duodenal humus occurs in the duodenum. The enzymes exert regulatory effects upon the glands producing them as well as upon secretion of other glands. They also take part in maintaining the organism enzyme homeostasis. The mechanisms of these effects are analysed.

Animals↗
PubMed1976

[Method for analyzing and estimating human resources for maternal and child care programs].

This report described the version of the Human Resources Analysis and Estimation Method (MAERH) that was specially devised for analyzing maternal and child health and family planning personnel (the MAERH/AMI/1 version). The general features of the method are presented and its ability to analyze health programs and to estimate the human resources needed is emphasized. In addition, the operation and use of the method, its advantages and short-comings, as well as its development and possible adaptation to wider-ranging or more specific problems are described. Finally, the results obtained in the maternal and child health area of the State of Pernambuco, Brazil, are presented to exemplify the use of the method.

Allied Health Personnel↗
PubMed1997

Metabolic consequences of alcohol dependency.

Alcohol dependency leads to a variety of biochemical adaptations and morphological changes which may be considered as either adaptive or destructive. This ranges from the utilization of ethanol as a metabolic fuel, to overt tissue and cellular damage, and may lead to increases in morbidity and mortality. Virtually every organ system is affected by either acute and chronic ethanol exposure and numerous metabolic pathways are altered. As a consequence of these wide ranging effects, it is extremely difficult to cover every aspect of alcohol toxicity in a single review. Instead, attention is focussed on selected areas, such as nutrition and protein metabolism in the liver and bone (and to a lesser extent, skeletal muscle and the gastrointestinal tract). The aim is to illustrate the numerous ways in which alcohol affects the body.

Alcohol-Related Disorders↗
PubMed1988

The prism adaptation test in the preoperative evaluation of esodeviations.

We performed surgery according to the measurements found with the prism adaptation test (PAT) in 14 patients with acquired esodeviations. The amount of deviation, as determined with the prism cover test, ranged from 3 to 30 (mean 13.4) prism dioptres (PD) at distance. Prism-adapted deviations ranged from 31 to 57 (mean 41.2) PD. The average recession of the medial rectus was 4.8 mm, and the average resection of the lateral rectus was 6.7 mm. The mean esodeviation at distance after surgery was 6.8 PD. Our results suggest that the PAT may be useful and perhaps indispensable in the preoperative assessment of patients with certain types of acquired esodeviation.

Adaptation, Physiological↗
PubMed2003

A middle-range theory of caregiver stress.

The Roy adaptation model is a widely used nursing theory, but only a few studies have used it in the context of caregiving for the chronically ill. Many caregivers with chronically ill relatives suffer from stress and its consequences, and in an aging society, more and more people will be affected by stress. In this article, the author presents a middle-range theory of caregiver stress based on the Roy adaptation model as the first step in understanding the applicability of the Roy adaptation model in the context of stress in caregivers.

Adaptation, Psychological↗
PubMedDate not supplied

The pupillary response to light in the turtle.

When intense adapting lights are turned off, the pupil of the turtle, Pseudemys scripta elegans, enlarges. The recovery functions for pupillary dilation have different time constants that are defined by red- and green-sensitive cones and rods as they are affected by prior light adaptation and time in the dark. Pupillary area related to dilation responds over at least a three- to four-fold range. Following white-light adaptation, the course of pupil dilation in the dark shows a three-legged curve of differing time constants. With spectral-light adaptations, the contributions of separate classes of photoreceptors can be isolated. Red- and green-sensitive cones contribute shorter time constants of 3.31 and 3.65 min to prior white-light adaptation--4.81 and 4.18 min to prior spectral-light adaptations. Rods contribute a much longer time constant of 6.69 min to prior white-light adaptation--7.60 min to prior spectral-light adaptation. The ratios are in keeping with the flash sensitivities of photoreceptors in this same animal, as well as with psychophysical visual threshold mechanisms of color sensitivity.

Adaptation, Physiological↗
PubMed2005

Stress avoidance in a common annual: reproductive timing is important for local adaptation and geographic distribution.

Adaptation to local environments may be an important determinant of species' geographic range. However, little is known about which traits contribute to adaptation or whether their further evolution would facilitate range expansion. In this study, we assessed the adaptive value of stress avoidance traits in the common annual Cocklebur (Xanthium strumarium) by performing a reciprocal transplant across a broad latitudinal gradient extending to the species' northern border. Populations were locally adapted and stress avoidance traits accounted for most fitness differences between populations. At the northern border where growing seasons are cooler and shorter, native populations had evolved to reproduce earlier than native populations in the lower latitude gardens. This clinal pattern in reproductive timing corresponded to a shift in selection from favouring later to earlier reproduction. Thus, earlier reproduction is an important adaptation to northern latitudes and constraint on the further evolution of this trait in marginal populations could potentially limit distribution.

Adaptation, Physiological↗
PubMed1997

Altered proton extrusion in cells adapted to growth at low extracellular pH.

Intracellular pH (pHi) homeostasis is crucial to cell survival. Cells that are chronically exposed to a low pH environment must adapt their hydrogen ion extrusion mechanisms to maintain their pHi in the physiologic range. An important component of the adaptation to growth at low pH is the upregulation of pHi relative to the extracellular pH (pHe). To test the ability of low pHe adapted cells to respond to a pHi lowering challenge, a fluorescence assay was used that directly monitors proton removal as the rate of change of pHi during recovery from cytosolic acidification. Two cell lines of Chinese hamster origin (ovarian carcinoma and ovary fibroblastoid cells) were compared, both of which showed altered proton extrusion after adaptation to growth at low pHe = 6.70. In the ovarian carcinoma (OvCa) cell line, the pattern was consistent with an upregulation by means of an increase in the number of functional proton transporters in the plasma membrane. In the ovary fibroblastoid (CHO-10B) cell line, pHi was consistently elevated in adapted cells as compared with cells grown at normal pHe = 7.30 without an increase in maximum extrusion rate. This upregulation was consistent with a shift in the activating pHi of proton transporters without an increase in the number of transporters, i.e., a change in substrate affinity of the transporter. In OvCa cells, recovery from acidification could be blocked by amiloride, an inhibitor of Na+/ H+ exchange. In contrast, a more modest effect of amiloride on CHO cells was observed but a complete inhibition was seen with the Cl-/HCO(-3)exchange inhibitor 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS). These data indicate that the two cell lines rely to different degrees on the two major pathways for pH regulation during recovery from cytosolic acidification.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed2004

Safety of antitumour necrosis factor (anti-TNF) therapy in patients with chronic viral infections: hepatitis C, hepatitis B, and HIV infection.

Tumour necrosis factor alpha (TNFalpha) is a pivotal cytokine in host defences with broad ranging effects on the innate and adaptive immune systems. Clinically, TNFalpha inhibitors have demonstrated remarkable efficacy in a wide range of autoimmune and inflammatory disorders but clearly at the cost of heightened susceptibility to a variety of infections in those treated with these agents. Most reports to date have described increased susceptibility to intracellular pathogens in patients with underlying chronic viral infections, but little in the way of adverse event reporting in these patients has occurred. While the reported experience to date is rather limited, TNFalpha inhibitors have displayed a reasonable safety profile in the setting of some chronic viral infections and in certain circumstances have demonstrated adjunctive activity in the treatment of these infections. Given the high prevalence of chronic viral infections in patients who are candidates for anti-TNF therapy and the potential for these agents in the treatment of chronic viral illness, additional studies are urgently needed to assess the risks and benefits of such therapy in these populations.

Antirheumatic Agents↗
PubMed1995

The influence of onset sound level of test stimulus on reported magnitude of changing-loudness aftereffects.

An increasing-loudness aftereffect follows adaptation to a tone of decreasing sound level; a decreasing-loudness aftereffect follows adaptation to a tone of increasing sound level. Contrary to the belief that sensory processing contributes to these changing-loudness aftereffects, evidence suggests that onset sound level of test stimulus may have little influence on reported aftereffects. This was tested formally in the present study. Adapting stimuli and test stimuli all employed 1-kHz sinusoidal carriers: Three onset sound levels of test stimuli were well within the range of sound levels encompassed by adapting stimuli; a fourth was set at the highest value of this range. Consistent with previous evidence, substantial aftereffects were reported for all the midrange onset sound levels, with little difference across onset sound levels. However, for the high-range onset sound level, reported aftereffects were severely attenuated. Sensory processing can be invoked by supposing that aftereffect mechanisms "tap" neural activity that encodes adapting sound levels.

Humans↗
PubMed1999

An efficient, adaptive method of measuring loudness growth functions.

This paper presents a new categorical loudness scaling procedure that differs from previously published loudness scaling procedures by (i) adaptively selecting a new set of levels for each new sequence, (ii) deriving levels that are equispaced on the loudness scale, and (iii) using a continuous scale with few labels. A major advantage of the adaptive procedure is that the individual dynamic range need not be measured prior to loudness testing. The adaptive procedure proved to be time efficient and to produce complete loudness functions from Not heard to Uncomfortably loud for normal hearing and hearing impaired subjects. The pattern of short-term and long-term reliability was similar to that reported for non-adaptive loudness scaling procedures. Three presentations produced a stable loudness function. Normative curves for one octave babble-noise at six test frequencies are presented and compared to normative data obtained with a selection of published categorical scaling procedures.

Adolescent↗
PubMed1984

Light regulation of photosynthetic membrane structure, organization, and function.

The light environment during plant growth determines the structural and functional properties of higher plant chloroplasts, thus revealing a dynamically regulated developmental system. Pisum sativum plants growing under intermittent illumination showed chloroplasts with fully functional photosystem (PS) II and PSI reaction centers that lacked the peripheral chlorophyll (Ch1) a/b and Ch1 a light-harvesting complexes (LHC), respectively. The results suggest a light flux differential threshold regulation in the biosynthesis of the photosystem core and peripheral antenna complexes. Sun-adapted species and plants growing under far-red-depleted illumination showed grana stacks composed of few (3-5) thylakoids connected with long intergrana (stroma) thylakoids. They had a PSII /PSI reaction center ratio in the range 1.3-1.9. Shade-adapted species and plants growing under far-red-enriched illumination showed large grana stacks composed of several thylakoids, often extending across the entire chloroplast body, and short intergrana stroma thylakoids. They had a higher PSII /PSI reaction center ratio, in the range of 2.2-4.0. Thus, the relative extent of grana and stroma thylakoid formation corresponds with the relative amounts of PSII and PSI in the chloroplast, respectively. The structural and functional adaptation of the photosynthetic membrane system in response to the quality of illumination involves mainly a control on the rate of PSII and PSI complex biosynthesis.

Chlorophyll↗
PubMed2001

Primary adult human bone cells do not respond to tissue (continuum) level strains.

Bone adapts to its mechanical environment, and, since the late 1800s, investigators have presumed that this adaptation relates to strain magnitude. Indeed, overwhelming evidence supports the view that either strain or some strain-related quantity stimulates bone adaptation or remodeling. Virtually all investigators, implicitly or explicitly, assume that the level of strain magnitude responsible for bone adaptation is that measured by strain gauges in vivo (i.e., 100-2500 microstrain) and that bone cells are directly deformed by strained matrix. We present evidence that bone cell deformation in this range does not cause bone adaptation. First, bone cells in vitro typically do not respond to average (continuum) levels of strain magnitude. Second, bone cells in vitro do respond to fluid flow-induced shear stresses in these ostensible physiological ranges. Third, in vivo strain magnitudes presumed to stimulate remodeling reflect only averages, and not local peaks, which are 2-15 times higher. Thus, we hypothesize that sensing cells do not respond to levels of strain presumed to be physiological.

Adaptation, Physiological↗
PubMed2003

Coping and adaptation at six months after stroke: experiences with eating disabilities.

Stroke produces a range of enduring impairments and survivors' coping and adaptation styles are influential features of life after stroke. Many stroke-sequelae affect ability to eat but survivors' perceptions and responses to these have not been explored.Methods. Survivors of a cohort of patients admitted to hospital with acute stroke March 1998-April 1999 participated in semi-structured interviews in their homes at 6 months post-stroke. Interviews were tape recorded and transcribed; 113 interviews with eating-disabled subjects were entered onto QSR NUD*IST 4 for thematic analysis.Findings. Two major emergent themes of 'getting back to normal' and 'getting by' were revealed which encompassed a range of responses in relation to food and eating. A high level of congruence was demonstrated with pre-existent frameworks but with some unique features. Reportage demonstrated non-linear and inconsistent effects of impairments within patients' lives and the importance of this topic for survivors and healthcare professionals was clear.

Adaptation, Psychological↗