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PubMed1985

A prospective multicentre study to develop universal immunochemical tests for predicting the fertile period in women. World Health Organisation Task Force on Methods for the Determination of the Fertile Period, Special Programme of Research, Development and Research Training in Human Reproduction.

Two immunochemical tests for predicting the fertile period have been adapted for application throughout the world. The estrone test involves the measurement of estrone-3-glucuronide (E1-3-G) in daily samples of early morning urine. The start of the fertile period is identified by a sustained rise in the concentration of E1-3-G (as determined by cumulative sum analysis); the end of potential fertility occurs 120 hours (5 days) after the peak level. Alternatively, the ratio of E1-3-G to pregnanediol-3 alpha-glucuronide (Pd-3 alpha-G) can be calculated and the fertile period identified between a defined rise in this index and the peak value plus 144 hours (6 days). One hundred thirty-one women from 10 countries provided samples from 557 menstrual cycles, and the results from 455 (82%) were accepted for statistical analysis. There were highly significant differences (P less than 0.0001) in the concentrations of the metabolites between centres, but the time intervals between both the rise and peak days and the day of the luteinizing hormone (LH) peak were less significantly different (P less than 0.05) for the estrone test and not significantly different for the ratio test. The fertile period was defined as the day of the LH peak -3 to the day of the LH peak +2. The estrone test successfully delineated this phase in 78% of menstrual cycles, and the ratio test, in 74%. The mean lengths of the derived fertile periods by both methods were 9.3 (SD 2.3) and 10.0 (SD 2.4) 24-hour periods (or days), respectively.

Adult↗
PubMedDate not supplied

[LBNP training of crew members of the Saliut-6 orbital station].

This paper describes the protocols of LBNP training of five prime crews that flew onboard Salyut-6. It is indicated that LBNP is one of the major constituents of countermeasures that must be performed inflight. LBNP may help adapt to weightlessness-induced blood redistribution and predict the level of postflight orthostatic tolerance.

Adaptation, Physiological↗
PubMedDate not supplied

[Human diffusion of arthropod disease vectors throughout the world].

The present distribution of animals and plants throughout the world is the result of an evolutionary process involving tectonic, climatic and biotic factors. Humans, since their appearance, have contributed to the spreading of many species including disease vectors and pests. When humans left their native African home, they brought with them ectoparasites such as lice and acarids. During the neolithic era, humans were leading domesticated animals which carried their own parasites into new areas. Dwelling commensals, flea, bugs, triatomids, flies, and cockroaches followed human migrations. In the second millennium, sailboats transported mosquito species which were resistant and reproduced on board, including Culex quinquefasciatus, Aedes aegypti, and Ae. albopictus. Steamers further shortened the length of trips and allowed the transport of anophelines. The opening of the Tamatave-Port-Louis line was immediately followed by the transport of An. gambiae from Madagascar to Mauritius and Reunion, and epidemics of malaria occurred on the two islands which had been free of the disease. Also, An. gambiae was transported from Senegal to Brazil. Old tires destined for recycling carried Ae. albopictus to the USA, Brazil, and then Italy. The pandemic of the plague at the end of the nineteenth century was propagated from harbour to harbour by steamers carrying both infected rats and their fleas Xenopsylla cheopsis. Aircrafts have reduced the travel time so much that in less than two days an insect could reach every point of the world. As soon as the airports had been built on the islands of French Polynesia, they were all colonized by Ae. aegypti. The same phenomenon occurred with midges (Fig. 2). Also, the construction of the airport on a Galapagos Island coincided with the importation of the blackfly Simulium bipunctatum from the continent. In addition, infected malaria mosquitos imported from tropical countries reached Europe and contaminated airport employees and local inhabitants. Six cases of malaria were recorded during the summer of 1994 around the Charles de Gaulle Airport, north of Paris, suggesting that the anophelines could have been imported from West and Central African countries which are served by this airport. The serious threat of vector importation is moderated by the vector's difficulty in adapting to new conditions. However any prediction is questionable.

Animals↗
PubMed1997

The effects of industrial employment conditions on job-related distress.

This paper examines the interaction between the effects of industrial unemployment and job conditions on workers' levels of psychological distress. Previous research finds that economic stress, defined as contexts of high unemployment, mainly affects distress indirectly through deteriorating job conditions. However, adaptive cost and identity salience hypotheses predict that the effects of industrial- and job-level conditions interact. I test for cross-level interactions between industrial unemployment and job demands and complexity using hierarchical linear modeling, individual data for 7,095 workers from the 1987-1988 National Survey of Families and Households, and industry data from the Bureau of Labor Statistics' 1986-1988 Current Population Surveys. Economic stress at the industrial level has a direct positive effect on worker distress, and economic stress is more distressing to workers in rewarding, complex jobs. In contrast, job demands increase distress, but this effect does not interact with industrial employment conditions.

Adult↗
PubMed1998

[High resolution ultrasound imaging: value in treatment of basocellular carcinoma by cryosurgery].

OBJECTIVE: We conducted a prospective evaluation of the contribution of high-resolution ultrasound imaging prior to cryosurgery for basocellular carcinoma and in search for recurrence. PATIENTS AND METHODS: All patients seen between 1992 and 1994 at the skin tumor clinic and treated by cryosurgery were included. Ultrasound imaging using 20 MHz prototype was performed prior to cryosurgery and 2 months later. RESULTS: Among 101 patients treated, 112 basocellular carcinomas were treated by cryosurgery. Ultrasound imaging provided good visualization of the tumor limits in all cases. The ultrasound aspect was anechogenic, often with rare areas of highly dense echoes. The tumor limits described by ultrasound imaging were larger than the clinical limits in 32% of the cases. In 8 of the 16 cases of recurrent tumors, the ultrasound examination revealed the recurrence first. In the other 8 cases, clinical manifestations were confirmed by ultrasonography. In our series, recurrence of basocellular carcinoma was statistically more frequent when the depth of the tumor was 3 mm (ultrasonographic measurement) or when the lateral limits established by ultrasound assessment were greater than the clinical evaluation. DISCUSSION: These findings demonstrate that high-resolution ultrasound imaging of basocellular carcinomas prior to cryosurgery: 1) visualizes tumor limits allowing adapted cryosurgery, 2) identifies factors with predictive value for recurrence, 3) can identify recurrences early. Ultrasound imaging of the skin is a useful non-invasive technique for pre- and post-therapeutic assessment of skin tumors and could be a particularly useful tool for "blind" cryosurgery destruction of skin tumors.

Adult↗
PubMed1998

The vertical field border in hemianopia and its significance for fixation and reading.

PURPOSE: The existence of macular sparing, a central seeing area of several degrees within the hemianopic field defect, has been controversial for a long time, because inaccurate fixation during perimetry can produce ambiguous results. The visual field border in hemianopia was studied to examine whether a vertical strip of hemifield overlap described in monkeys exists in humans and whether additional macular sparing could be found. METHODS: Vertical triplets of dots were scanned on the retinas of eight patients (13 eyes) with hemianopia at different eccentricity from the vertical meridian during strict simultaneous fixation control using a scanning laser ophthalmoscope (SLO). Additionally, eye movements were measured by SLO and by an infrared reflection system while subjects read texts. RESULTS: Macular sparing of 2 degrees to 5 degrees and absence of sparing were observed. The presence and amount of sparing influenced fixation behavior, reading performance, and reliability of conventional perimetry. The smaller the macular sparing, the less stable the fixation. In the absence of sparing, either central unstable fixation with frequent saccades toward the hemianopic side or eccentric fixation occurred, resulting in a shift of the field defect toward the hemianopic side. A vertical strip of sometimes partial perception was found in 12 eyes at 0.5 degrees from the midline. CONCLUSIONS: Macular sparing and a slight vertical strip of hemifield overlap exists in humans. Adaptive strategies like eccentric fixation and predictive saccades improve reading performance and can augment rehabilitation.

Adult↗
PubMedDate not supplied

[Methods for improving the quality of prediction in the process of automatic annotating A4].

Modifications of the previously described adaptive algorithm of automatic annotating A4 have been considered, which make it possible to improve the quality of prediction. First, the direct use of the so-called basis statistics eta refines the quality of prediction compared with the previously proposed statistics gamma. Second, the quality is improved if not all similar sequences found but only part of them are used. This decreases the noising of the data, which in turn improves the quality of prognosis.

Algorithms↗
PubMed2004

Sensorimotor gating abnormalities in young males with fragile X syndrome and Fmr1-knockout mice.

Fragile X syndrome (FXS) is the most common single gene (FMR1) disorder affecting cognitive and behavioral function in humans. This syndrome is characterized by a cluster of abnormalities including lower IQ, attention deficits, impairments in adaptive behavior and increased incidence of autism. Here, we show that young males with FXS have profound deficits in prepulse inhibition (PPI), a basic marker of sensorimotor gating that has been extensively studied in rodents. Importantly, the magnitude of the PPI impairments in the fragile X children predicted the severity of their IQ, attention, adaptive behavior and autistic phenotypes. Additionally, these measures were highly correlated with each other, suggesting that a shared mechanism underlies this complex phenotypic cluster. Studies in Fmr1-knockout mice also revealed sensorimotor gating and learning abnormalities. However, PPI and learning were enhanced rather than reduced in the mutants. Therefore, these data show that mutations of the FMR1 gene impact equivalent processes in both humans and mice. However, since these phenotypic changes are opposite in direction, they also suggest that murine compensatory mechanisms following loss of FMR1 function differ from those in humans.

Acoustic Stimulation↗
PubMedDate not supplied

Rapid adaptation and efficient coding.

Rapid adaptation is a prominent feature of biological neuronal systems. From a functional perspective the adaptation of neuronal properties, namely the input-output relation of sensory neurons, is usually interpreted as an adaptation of the sensory system to changing environments as characterized by their stimulus statistics. Here we argue that this interpretation is only applicable as long as the adaptation processes are slower than the time-scale at which the stimulus statistics change. We present a definition of optimality of a neuronal code which still captures the idea of efficient coding, but which can also explain rapid adaptation without referring to an adaptation to different sensory environments. Finally, we apply our new idea to a simple model of an orientation hypercolumn in the primary visual cortex and predict that the interactions between orientation columns should adapt at the time-scale of a single stimulus presentation.

Adaptation, Biological↗
PubMed2004

Moving objects in a rotating environment: rapid prediction of Coriolis and centrifugal force perturbations.

Grip force adaptation to Coriolis and centrifugal force perturbations was tested in healthy subjects. Eight subjects were seated in a rotating chamber in a rotating axis position. They each grasped an instrumented object resting on the thumb, which was stabilized by the other fingers from above. Subjects performed horizontal point-to-point movements with the grasped object away and towards the trunk. These movements were directed in a nonparallel fashion towards the axis of rotation prior (40 pre-rotational movements), during (80 per-rotational movements) and following (40 post-rotational movements) clockwise body rotation. During pre- and post-rotational movements two load force peaks of similar magnitude occurred during the acceleratory and deceleratory phases of the movements. Accordingly, a Coriolis force, which was orthogonal and proportional to the linear velocity of the moving arm, as well as a centrifugal force proportional to the system's squared angular velocity and movement amplitude developed during per-rotational movements. The load perturbations altered the load force profile in a characteristic way. The first 10 per-rotational movement sequence revealed that there was a less precise coupling between grip and load force magnitudes and a reduced temporo-spatial co-ordination between grip and load force profiles. With increasing number of per-rotational movements, there was significant improvement in the temporo-spatial co-ordination and in the coupling in force magnitude between grip and load force profiles, indicating an ongoing adaptation process. The coupling between grip and load forces proved to be similarly precise for the last 10 per-rotational movements and for pre-rotational movements, suggesting complete adaptation. Significant effects were observed for the first post rotational movements following adaptation to the per-rotational load characteristics both for the temporal co-ordination between grip and load forces and for the coupling in force magnitudes. However, the last 10 post-rotational movements proved to be similarly precise with comparison to pre-rotational performance in terms of grip force regulation with movement-induced loads. The results are discussed within the context of the CNS ability to use internal models when planning and processing anticipatory grip force adjustments during manipulative tasks.

Acoustic Stimulation↗
PubMed1999

Reproducibility of the Adapted Leger and Boucher Test for wheelchair-dependent athletes.

STUDY DESIGN: This study analyzed the reproducibility of a field test. In a previous study, we showed that this test, the Adapted Leger and Boucher Test (ALBT), was progressive and maximal. The Leger and Boucher predictive equation for able-bodied subjects was not accurate for WD athletes, however, and a new predictive equation is needed. OBJECTIVES: To determine the reproducibility of an adapted incremental field test for wheelchair-dependent (WD) athletes. SETTING: France at Montpellier. METHODS: The proposed protocol was conducted on a 400 m track. Eight male paraplegics (mean age: 30.8+/-5.1 years) performed the test three times in the same conditions, ie same time of day, same wheelchair, same material. Maximal heart rate (HRmax) and maximal speed (Smax) were measured. RESULTS: We found no significant differences (P>0.05) between tests for either variable. The Bland and Altman graphic analyses showed a good reproducibility for both variables. Lastly, the reproducibility coefficients of HRmax and Smax were very low (2% and 1%, respectively). CONCLUSION: The ALBT is reproducible concerning measurements of HRmax and Smax. A valid predictive equation of maximal oxygen uptake from the Smax is now needed for WD athletes during this field test.

Adult↗
PubMed2003

Styles of adaptation in panic disorder with and without agoraphobia.

Two groups of women with a main DSM-IV diagnosis of panic disorder, one with and one without agoraphobia (respectively, n = 26 and n = 14) were compared on several clinical variables. Forward logistic regressions were run for the presence of agoraphobia. Age of onset, duration of illness, presence of major depressions, and cluster classification on Axis II did not predict the criterion variable. Diagnosis and scores on avoidant personality disorder led, respectively, to 65% and 72.5% rates of correct classifications. Among panic symptoms, fear of going crazy and palpitations significantly predicted agoraphobia (75% of correct allocations). Three adaptive variables assessed by the Serial Color-Word Test (a serial version of the Stroop task) led to a 90% rate of correct classification. Agoraphobic patients were mainly characterized by an anxious or over-controlling style, which permitted a pseudo-objective mastery of the conflict situation. The findings seem to support the clinical relevance of the Serial Color-Word Test.

Adaptation, Psychological↗
PubMed2006

Evidence for adaptive male mate choice in the fruit fly Drosophila melanogaster.

Theory predicts that males will benefit when they bias their mating effort towards females of higher reproductive potential, and that this discrimination will increase as males become more resource limited. We conducted a series of experiments to test these predictions in a laboratory population of the fruitfly, Drosophila melanogaster. In this species, courtship and copulation have significant costs to males, and females vary greatly in fecundity, which is positively associated with body size. When given a simultaneous choice between small and large virgin females, males preferentially mated with larger, more fecund, females. Moreover, after males had recently mated they showed a stronger preference for larger females. These results suggest that male D. melanogaster adaptively allocate their mating effort in response to variation in female quality and provide some of the first support for the theoretical prediction that male stringency in mate choice increases as resources become more limiting.

Adaptation, Physiological↗
PubMed1991

Symptom schemata in chronic respiratory patients.

In view of evidence that illness prognoses and adaptive functioning may be influenced by the accuracy of people's knowledge about their physical symptoms, the present study extended these findings to the chronic care population. It was hypothesized that individuals hold beliefs and develop theories about their physical symptoms and that the accuracy of these beliefs is predictive of the individuals' general level of adaptive functioning. A modified version of an instrument designed to measure the accuracy of illness schemata was employed with a sample of 31 chronic respiratory patients. Accuracy rating correlated positively and significantly with ratings of adaptive functioning, whereas no relationship was observed between adaptive functioning and severity of the patients' medical condition. Well-informed patients functioned at a higher level physically, psychologically, and socially than less-informed patients. These findings point to the importance of patient education for prognosis. Possible mediating factors are discussed.

Adult↗
PubMed2001

Evolution of thermal dependence of growth rate of Escherichia coli populations during 20,000 generations in a constant environment.

Twelve experimental populations of the bacterium Escherichia coli evolved for 20,000 generations in a defined medium at 37 degrees C. We measured their maximum growth rates across a broad range of temperatures and at several evolutionary time points to quantify the extent to which they became thermal specialists with diminished performance at other temperatures. We also sought to determine whether antagonistic pleiotropy (genetic trade-offs) or mutation accumulation (drift decay) was primarily responsible for any thermal specialization. Populations showed consistent improvement in growth rate at moderate temperatures (27-39 degrees C), but tended to have decreased growth rate at both low (20 degrees C) and high (41-42 degrees C) temperatures. Most loss occurred early in the experiment, when adaptation was most rapid. This dynamic is predicted by antagonistic pleiotropy but not by mutation accumulation. Several populations evolved high mutation rates due to defects in their DNA repair, but they did not subsequently undergo a greater decrease in growth rate at thermal extremes than populations that retained low mutation rates, contrary to the acceleration of decay predicted by mutation accumulation. Antagonistic pleiotropy therefore is more likely to be responsible for the evolution of thermal specialization observed in maximum growth rate.

Adaptation, Physiological↗
PubMed1998

Relationship between burnout and sense of coherence in health social workers.

The aim of this study was to determine whether a strong sense of coherence as a coping strategy affects burnout in health social workers. The research sample consisted of 31 social workers in the field of physical illness, 21 in the field of mental illness, and 29 in the field of the handicapped. The main finding indicates that health social workers who have a strong sense of coherence experience less burnout than those with a weak sense of coherence. More specifically, the findings indicate that the manageability component of sense of coherence predicts emotional exhaustion.

Adaptation, Psychological↗
PubMed2005

Evaluation of robotic training forces that either enhance or reduce error in chronic hemiparetic stroke survivors.

This investigation is one in a series of studies that address the possibility of stroke rehabilitation using robotic devices to facilitate "adaptive training." Healthy subjects, after training in the presence of systematically applied forces, typically exhibit a predictable "after-effect." A critical question is whether this adaptive characteristic is preserved following stroke so that it might be exploited for restoring function. Another important question is whether subjects benefit more from training forces that enhance their errors than from forces that reduce their errors. We exposed hemiparetic stroke survivors and healthy age-matched controls to a pattern of disturbing forces that have been found by previous studies to induce a dramatic adaptation in healthy individuals. Eighteen stroke survivors made 834 movements in the presence of a robot-generated force field that pushed their hands proportional to its speed and perpendicular to its direction of motion--either clockwise or counterclockwise. We found that subjects could adapt, as evidenced by significant after-effects. After-effects were not correlated with the clinical scores that we used for measuring motor impairment. Further examination revealed that significant improvements occurred only when the training forces magnified the original errors, and not when the training forces reduced the errors or were zero. Within this constrained experimental task we found that error-enhancing therapy (as opposed to guiding the limb closer to the correct path) to be more effective than therapy that assisted the subject.

Acceleration↗