Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Period Analysis”

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 703 records · Page 39Linked to original sources
PubMed2006

Changes in soluble carbohydrates during storage of Caesalpinia echinata LAM. (Brazilwood) seeds, an endangered leguminous tree from the Brazilian Atlantic Forest.

Caesalpinia echinata seeds stored in laboratory environmental conditions lose their viability in one month whilst under low temperatures germination is maintained for 18 months of storage. These seeds are tolerant to desiccation, keeping their viability up to 0.08 gH2O.gDW-1. Since soluble carbohydrates are believed to be involved with desiccation tolerance and seed storability, the aim of this work is to analyze the content and composition of soluble carbohydrates in C. echinata seeds during storage in paper bags (PB) and glass flasks (GF) at laboratory room (RT) and cool (CT) temperatures. In freshly harvested seeds, total soluble carbohydrates comprised approximately 10% of the dry weight, decreasing to ca. 8% over 18 months of storage at RT. In seeds stored at CT, sugars varied differently decreasing initially and being restored at the end of the analysis period. The main neutral sugars in seeds from all treatments were sucrose, fructose and glucose. Raffinose and stachyose were present as traces. Free myo-inositol and other cyclitols were also detected. The main tendency observed was the variation in levels of both glucose and fructose in relation to sucrose, the highest levels of monosaccharides which were found in seeds stored at CT. The values of glucose and fructose were practically constant in seeds stored in paper bags for 18 months at CT, decreasing consistently in the other treatments, mainly at RT. Sucrose contents remained relatively stable. Changes in soluble sugars during storage suggest that the loss of germinability of seeds of C. echinata could be associated with low levels of glucose and fructose in relation to sucrose.

Brazil↗
PubMed1979

Effects of lesions of the suprachiasmatic nuclei and of p-chlorophenylalanine on the circadian rhythms of adrenocorticotrophic hormone and corticosterone in the plasma, and on locomotor activity of rats.

Adrenocorticotrophin (ACTH) and corticosterone in the plasma of adult female rats were measured sequentially at 4 h intervals for 24 h before and after lesions of the suprachiasmatic nuclei or treatment with p-chlorophenylalanine (to inhibit serotonin synthesis). After lesions or p-chlorophenylalanine treatment, the concentrations of ACTH were diminished relative to those in control animals and rhythmic changes could not be detected. However, injection of animals, pretreated with p-chlorophenylalanine, with 5-hydroxytryptophan (60 mg/kg) 8 h before the time when plasma ACTH is maximal in intact animals, stimulated ACTH secretion up to control values. Mean corticosterone concentrations in plasma remained unchanged (after lesions) or increased (after p-chlorophenylalanine). This increase was associated with an increased minimal concentration of corticosterone. After both treatments there was evidence of continued circadian or ultradian rhythms of corticosterone concentration. Locomotor activity of female rats given identical treatment, but without blood sampling, indicated that nocturnal activity was diminished after lesions whereas diurnal activity was enhanced after p-chlorophenylalanine treatment. Periodicity analysis detected the persistence of free-running circadian, and sometimes ultradian activity, rhythms. Adrenalectomy did not alter further the activity pattern observed in rats with lesions. These results therefore support the proposition that both the suprachiasmatic nuclei and the serotoninergic system play an irreplaceable role in the mechanism of ACTH secretory rhythms. The suprachiasmatic nuclei are also important for synchronization of locomotor activity and corticosterone rhythms, which may both persist after the suppression of ACTH rhythms.

5-Hydroxytryptophan↗
PubMed1980

Seasonal variation in spontaneous abortions.

Using a national sample of hospital discharges, we found identical seasonal patterns for spontaneous abortions and conceptions but no significant seasonal variation in the rate of spontaneous abortions per 1,000 conceptions. The differences between our findings and those of previous investigators of spontaneous abortion may reflect our more comprehensive definition of spontaneous abortion, our more complete estimate of the monthly number of conceptions, and our more rigorous statistical analysis. The periodic regression analysis (PRA) reported in our study may be useful in other studies that monitor short-term trends.

Abortion, Spontaneous↗
PubMed1984

Discharge patterns of the slowly adapting mechanoreceptor afferent units innervating the non-warty skin of the frog.

Discharge patterns of slowly adapting (SA) mechanoreceptor afferent units innervating the non-warty skin of frogs, were analyzed statistically. Because SA units in the frog did not always produce sustained discharges for a long period, analysis was carried out on ensembles of interspike intervals (ISIs) obtained in two ways: (1) a series of successive ISIs obtained in the quasi-stationary state of maintained discharges and (2) an ensemble of ISIs (X(1),X(2),..., X(50)), obtained on repeated trials of stimulation at about 1,000 msec following the onset of stimulation. In some units these two types of ensembles of ISIs were collected. Statistical analysis of a series of successive ISIs in the quasi-stationary state disclosed two kinds of discharge patterns, irregular and regular, corresponding to those of the SA cutaneous units of mammals and reptiles. We named these two types of units Frog type I and Frog type II (Ft I and Ft II) units, respectively. In addition, the quantitative study of an ensemble of ISIs in the non-stationary state revealed that Ft II units discharged regularly in response to an optimum range of indentation but irregularly to indentation outside this range, although Ft I units produced irregular discharges irrespective of the magnitude of indentation applied.

Adaptation, Physiological↗
PubMed2003

Immobilization of lipases and assay in continuous fixed bed reactor.

Lipases are versatile enzymes regarding the range of reactions they catalyse and substrates on which they act. They are as well important as catalyst in organic synthesis. Their immobilization on appropriate supports confer them greater stability besides the possibility of operating in continuous reactors. In order to explore these abilities, the reactions involving hydrolysis of p-nitrophenyl acetate (PNPA) and transesterification of PNPA with n-butanol were chosen. Lipases from two different sources were assayed, namely: microbial (Candida rugosa, CRL, Sigma Type VII) and pancreatic (PPL, Sigma, Type II). Two immobilization methods were also used, namely: 1). adsorption, using as support the following silica derivatives (150-300 microm e 450micro): phenyl, epoxy, amino and without derivation, and 2). covalent binding, using glutaraldehyde as binding agent and silica amino as support. This later method led to better results. Hydrolytic activity was 6.1 U/g(support) for CRL and 0.97 U/g(support) for PPL, and of transesterification, 2,8 U/g(support) for CRL and 1,9 U/g(support) for PPL. Stability of the immobilized enzyme as a function of temperature was evaluated for CRL at 40 degrees C and 50 degrees C and for PPL at 32 degrees C and 40 degrees C. The assays were initially carried out batchwise, both for soluble and immobilized enzymes, aiming to the obtention of parameters for the continuous reactor. Lipases immobilized by covalent binding were used in the assays of operational stability in continuous reactors. For PPL in aqueous medium, at 32 degrees C, and CRL in organic medium at 40 degrees C, both operating continuously, no significant loss of activity was detected along the analysis period of 17 days. In the case of CRL in aqueous medium at 40 degrees C there was a loss of activity around 40% after 18 days. For PPL in organic medium at 40 degrees C the loss was 33% after 20 days. Comparing both sources with each other, very different results were obtained. Higher activity was found for CRL, both for hydrolysis and for transesterification reactions, with higher stability in organic medium. PPL showed lower activity as well as higher stability in aqueous medium. The immobilization method by covalent binding showed to be the most appropriate. Immobilized lipases are therefore relatively stable both in aqueous and organic medium.

Adsorption↗
PubMedDate not supplied

Reminiscence intervention in nursing homes: what and who changes?

The results of experimental studies of reminiscing are not as uniformly optimistic about its therapeutic value as is the theoretical literature. Moreover, anecdotal evidence regarding the impact of reminiscence interventions is more positive than the statistical evidence. This study suggests reasons for these previous findings, and examines data from a discussion group intervention in thirty nursing homes, in which 185 residents completed pre- and posttests. It analyzes the characteristics of participants in relation to modifications in selected attitudes and behaviors over the intervention period. Analysis of variance and discriminant analysis revealed no significant relationships between attitudinal or behavioral modifications and demographic or other characteristics, with one exception. Value-choices made by participants were related to such modifications. The findings are interpreted in terms of the "mental adaptability" of participants and the compensatory nature of reminiscence in an institutional setting.

Adaptation, Psychological↗
PubMed1993

Relationship between glycemic control and collagen-linked advanced glycosylation end products in type I diabetes.

OBJECTIVE: To evaluate the relationship between glycemic control over a 3-yr period and tissue levels of advanced glycosylation end products. The development of renal failure, blindness, and generalized vascular occlusion continue to be the most serious ravages of diabetes. Tissue glycosylation and AGEs are felt to play an important role in the development of these sequelae, but no data are available on the relationship between AGEs and long-term glycemic control. RESEARCH DESIGN AND METHODS: We studied 48 subjects with type I diabetes. Glycemic control was determined by mean levels of HbA1, and AGEs were determined on collagenase digests of skin collagen by fluorescence at excitation/emission readings of 335/385 and 370/440 nm. RESULTS: To evaluate the relationship between glycemic control and AGE levels, control was classified as good (< or = 8.5%), fair (> 8.5% but < or = 10%), or poor (> 10%) on the basis of mean HbA1 levels during 1- and 3-yr periods. Analysis of the mean AGE levels for each level of glycemic control over 1-3 yr showed that AGEs differed significantly across categories of glycemic control (P = 0.04 and 0.003), with the lowest AGE levels associated with good and the highest with poor glycemic control. The relationship also was highly significant when adjusted for age, sex, and duration of diabetes, and when examined by Pearson's correlation coefficients (P = 0.02 and 0.008). CONCLUSIONS: Finding a relationship between glycemic control over 1-3 yr and tissue levels of AGEs suggests that AGEs can be modified and possibly reversed by improved glucose levels.

Adult↗
PubMed2001

Effects of hydrochlorothiazide and diet in dogs with calcium oxalate urolithiasis.

OBJECTIVE: To determine whether hydrochlorothiazide (HCTZ) reduces urinary calcium excretion in dogs with calcium oxalate urolithiasis. DESIGN: Original study. ANIMALS: 8 dogs with calcium oxalate urolithiasis. PROCEDURE: 4 treatment protocols were evaluated in each dog (a low calcium, low protein diet designed to prevent calcium oxalate urolith formation with and without administration of HCTZ [2 mg/kg (0.9 mg/lb) of body weight, PO, q 12 h] and a maintenance diet with higher quantities of protein and calcium with and without administration of HCTZ). At the end of each 2-week treatment period, 24-hour urine samples were collected. Blood samples were collected during the midpoint of each urine collection period. Analysis of variance was performed to evaluate the effects of HCTZ and diet on urine and serum analytes. RESULTS: Hydrochlorothiazide significantly decreased urine calcium and potassium concentration and excretion. Hydrochlorothiazide also significantly decreased serum potassium concentration. Compared with the maintenance diet, the urolith prevention diet significantly decreased urine calcium and oxalic acid concentration and excretion. Dogs consuming the urolith prevention diet had significantly lower serum concentrations of albumin and urea nitrogen. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of HCTZ decreased urine calcium excretion in dogs with a history of calcium oxalate urolith formation. The greatest reduction in urine calcium concentration and excretion was achieved when dogs received HCTZ and the urolith prevention diet. Results of this study suggest that the hypocalciuric effect of HCTZ will minimize recurrence of calcium oxalate urolith formation in dogs; however, long-term controlled clinical trials are needed to confirm the safety and effectiveness of HCTZ.

Animal Feed↗
PubMed1993

Phonological similarity effect is abolished by a silent mouthing task.

This experiment was designed to examine the effect of silent mouthing on the phonological similarity effect. 16 undergraduates were tested for serial recall of visually presented letter sequences that were either phonologically similar or dissimilar. The letter sequences had to be remembered under two conditions, a control condition and a silent mouthing condition in which subjects had to articulate irrelevant words silently during the study period. Analysis showed the clear advantage of the dissimilar sequence over the similar one in the control condition. In contrast, this phonological similarity effect disappeared in the silent mouthing condition. This result is consistent with the working memory model.

Adult↗
PubMed2000

An assessment of grade inflation in higher education.

Considerable research has been conducted on grade inflation and its pervasiveness. Given the significance of grade inflation on the quality of the educational experience and the reputations of colleges and universities, efforts to assess its presence and underlying causes should be supported and solutions developed. Because periodic changes in average grades in the short term may be anomalous, mean grade point averages (GPAs) for 262 undergraduate courses at a Liberal Arts college were examined for trends across a 10-yr. period. Analysis showed higher grades appeared within two of the colleges' four academic units, although the reasons remained unclear. Tentative explanations are explored.

Curriculum↗
PubMed2004

A microswitch program including words and choice opportunities for students with multiple disabilities.

Two students with multiple disabilities were provided with two or three request microswitches and one choice microswitch. Activation of a request microswitch triggered the verbal announcement of one of the stimulus events related to it. The student could choose such an event through the choice microswitch or bypass it. The request microswitches were introduced individually and made available simultaneously by the end of the intervention and the postintervention period. Analysis showed that both students learned to use the microswitches. Transfer of the microswitch program into the students' home was very successful with one student and presented some difficulties with the other. Implications of the findings and new possible developments were discussed.

Adolescent↗
PubMed2004

Aggressive behaviour in slot machine gamblers: a preliminary observational study.

Gambling is acknowledged to have many negative effects on individuals. However, from a psychological perspective, aggression as an outcome of gambling has been largely overlooked to date. The incidence of aggressive behaviour was monitored in 303 slot machine players over four 6-hr. observation periods. Analysis identified four types of common aggressive behaviour. These were (1) verbal aggression towards the gambling arcade staff, (2) verbal aggression towards the slot machines, (3) verbal aggression towards other slot machine players, and (4) physical aggression towards the slot machines. The findings add support to the increasing number of studies highlighting a possible link between gambling and aggression.

Adolescent↗
PubMed2006

Preliminary study of reminiscence therapy on depression and self-esteem in cancer patients.

The present study investigated use of life review, a form of reminiscence, on the depression and self-esteem in cancer patients. 15 cancer patients in the experimental group participated in individual reminiscence therapy. 21 patients in the comparison group received no therapy. All patients were measured on both depression and self-esteem scales during two testing periods. Analysis showed mean depression scores of the cancer patients decreased and mean self-esteem increased significandy after the life-review therapy sessions, while the scores of the comparison group did not change. Furthermore, patients' psychological states were improved, and they thought their problems had been addressed. These results suggest reminiscence therapy can be useful for cancer patients.

Depression↗
PubMed1987

Prognostic parameters in predicting pregnancy. A twenty-year follow-up study comprising semen analysis in 765 men of infertile couples evaluated by the Cox regression model.

The Cox proportional hazard regression model was employed on 765 infertile men whose semen had been analysed in 1950 and 1951 and who replied to a questionnaire 20 years later. Of nine clinical and laboratory variables evaluated, four possessed significant and independent prognostic information about the time required to conceive, when covariation between the variables was considered. They were: age of the man at semen analysis, percentage normal spermatozoa, percentage mobile spermatozoa, and the degree of motility. The four variables were combined to form a prognostic index, which permits prediction of individual pregnancy probability. The five variables which possessed no significant prognostic information were time from ejaculation to semen analysis, period of abstinence, existence of previous pregnancy, volume and sperm count. There was a satisfactory agreement between predicted and observed pregnancies in the present series. Thus, the index may prove clinically useful. However, its value must be established in other independent series.

Adult↗
PubMed1980

Auditory prostheses--a challenge for neurophysiology.

To achieve speech discrimination with prosthetic stimulation, pre-processing of speech adapted to the function to be replaced is indispensable. This is demonstrated using the example of a phase-conserving frequency transposition for a more efficient use of residual hearing. The intelligibility of transposed speech was investigated by employing simulated residual hearing. Long-term implanted electrodes in the auditory nerve of the cat permitted both the measurement of the natural activity of fibres and the application of corresponding stimulus currents. Phase reversal of the acoustic input was used to isolate a phasic response with a topographically differing proportional or differential behaviour. This suggests a periodicity analysis of the sound in the auditory pathway. In acoustic and electrical stimulation, additionally implanted, cortical control electrodes revealed largely corresponding potentials; the dynamic stimulation ranges, however, differed greatly. Finally, the possibility of assessing speech perception by measuring speech-evoked potentials is discussed.

Cochlear Implants↗
PubMed1981

The stability of blood, plasma and serum constituents during simulated transport.

The aim of the study was to simulate physical conditions occurring during mail transport and to study how these conditions influence the stability of material for clinical chemistry analysis. Periods of transport at constant temperatures did not result in big changes. We found that all serum and plasma constituents tested should be considered stable for 4 days at -20 degrees C. Except for the coagulation factors studied all other serum and plasma constituents were stable also at 4 degrees C and 20 degrees C. Blood cells were studied only at 4 degrees C at which temperature they were stable for 4 days except for thrombocytes. The condition that caused the largest effect was changing of temperature. Temperature gradient from ambient to 50 degrees C influenced the concentrations of all cells in blood, of coagulation factors in plasma and of enzymes in serum. The constituents were remarkably stable during shaking. The results agreed with those of a field study on the effect of mail transport by Berg et al. [3].

Blood↗
PubMedDate not supplied

Effects on experimental acute lung injury 24 hours after exogenous surfactant instillation.

Subcutaneous injection of N-nitroso-N-methylurethane (NNNMU) produces an acute lung injury mimicking the adult respiratory distress syndrome. NNNMU-injured rats treated with intratracheal Survanta, 100 mg phospholipid/kg body weight, air, or normal saline were observed for 24 h. Twenty-four hours after treatment survival among Survanta-treated rats was significantly greater than for air- and saline-treated rats (9/15 vs. 2/15 and 3/15, respectively). The alveolar-to-arterial O2 gradient was lower in Survanta-treated than in either air- or saline-treated rats during the 24-h period. Analysis of bronchoalveolar lavage fluid revealed a higher phospholipid: protein ratio (1.73 +/- 0.31 Survanta-treated, 0.20 +/- 0.05 air control, and 0.41 +/- 0.17 saline control) and a more normal phospholipid composition among treated than control rats. Minimum dynamic surface tension was significantly lower among treated rats (10.9 +/- 2.9 dyn/cm) than air and saline control rats (36.0 +/- 0.6 and 35.8 +/- 1.0 dyn/com, respectively). In vitro mixing of surfactant with pulmonary edema proteins significantly raised the minimum surface tension of surfactant from a group of Survanta-treated, NNNMU-injured rats (8.7 +/- 3.5 dyn/cm before and 32.0 +/- 0.5 dyn/cm after mixing). Intratracheal Survanta shows a beneficial effect on physiologic parameters and biochemical and functional characteristics of alveolar surfactant for 24 h in rats with NNNMU-induced acute lung injury.

Animals↗
PubMed1989

Effects of endurance exercise on nocturnal hormone concentrations in males.

A preliminary study was conducted to evaluate the change in nocturnal concentrations of testosterone, luteinizing hormone, growth hormone, prolactin, thyroxine, and cortisol following a control day (no exercise) and on a day in which exercise was performed. Exercise consisted of 90 min of cycling at 70% of each subject's maximal oxygen uptake. The exercise occurred from 1630 to 1800 hr on the exercise day while a comparable period of rest took place on the control day. Hormonal concentrations were evaluated at 2-hr intervals for a 12-hr period each night (2000-0800 hr). The subjects slept from 2255 (+/- 20 min [X +/- S.E.M.]) until 0715 (+/- 15) during each night. All hormone responses were plotted and integrated for the 12-hr period. Analysis indicated that a significant augmentation of the prolactin and thyroxine responses occurred, while concurrently an attenuation of the growth hormone and cortisol responses were observed. Contrastingly, no significant effects were found for the testosterone and luteinizing hormones responses. The physiological significance of these findings remained to be determined, but the results do suggest that further research is warranted in the area.

Adult↗