Absolute Temperature Thresholds for Detection of Skin Wetness and Dampness on the Hand and their Variation with Sex and Age

Perception ◽  
2021 ◽  
pp. 030100662110434
Author(s):  
Sandhya Kumar ◽  
Surabhi Kumar

The human body has dedicated receptors for sensing temperature and touch, but not wetness. How then is wetness perceived? To test if wetness perception arises from the sensory integration of touch and temperature, and to quantify its measurement in humans, we designed a wetness perception monitor (WPM) which enabled variation of temperature at the fingertips of participants while measuring the pressure exerted on a test surface in the controlled environment of a moisture-free chamber. Thirty randomly selected adults (18+ years) were tested for their perception of dampness/wetness using the WPM. Our data suggest that humans perceive dampness and wetness at average temperatures of 22 ± 0.4°C and 18 ± 0.5°C, respectively, and these sensations are extinguished at temperatures below 16 ± 1°C. Measurements were obtained at an average tactile pressure of 1.5 ± 0.3 kPa. Young adults (18–35 years) sensed wetness at significantly higher temperatures than middle-aged adults (36–55 years) or mature adults (56+ years), who sensed wetness at similar temperatures. We found a surprising sex difference in wetness perception, with females sensing wetness at higher temperatures than males. When the data were screened for outliers, we found that participants whose readings were outside normal ranges, self-reported sensory deficits suggesting that wetness perception could potentially be used as a noninvasive biomarker.

2021 ◽  
Vol 288 (1954) ◽  
pp. 20202725
Author(s):  
Fabienne Krauer ◽  
Hildegunn Viljugrein ◽  
Katharine R. Dean

Modern plague outbreaks exhibit a distinct seasonal pattern. By contrast, the seasonality of historical outbreaks and its drivers has not been studied systematically. Here, we investigate the seasonal pattern, the epidemic peak timing and growth rates, and the association with latitude, temperature, and precipitation using a large, novel dataset of plague- and all-cause mortality during the Second Pandemic in Europe and the Mediterranean. We show that epidemic peak timing followed a latitudinal gradient, with mean annual temperature negatively associated with peak timing. Based on modern temperature data, the predicted epidemic growth of all outbreaks was positive between 11.7°C and 21.5°C with a maximum around 17.3°C. Hence, our study provides evidence that the growth of plague epidemics across the whole study region depended on similar absolute temperature thresholds. Here, we present a systematic analysis of the seasonality of historical plague in the Northern Hemisphere, and we show consistent evidence for a temperature-related process influencing the epidemic peak timing and growth rates of plague epidemics.


1976 ◽  
Vol 19 (6) ◽  
pp. 1152-1155 ◽  
Author(s):  
P. M. Singh ◽  
J. R. Gilley ◽  
W. E. Splinter

Author(s):  
R. Chen

ABSTRACT:Cutaneous reflexes in the upper limb were elicited by stimulating digital nerves and recorded by averaging rectified EMG from proximal and distal upper limb muscles during voluntary contraction. Distal muscles often showed a triphasic response: an inhibition with onset about 50 ms (Il) followed by a facilitation with onset about 60 ms (E2) followed by another inhibition with onset about 80 ms (12). Proximal muscles generally showed biphasic responses beginning with facilitation or inhibition with onset at about 40 ms. Normal ranges for the amplitude of these components were established from recordings on 22 arms of 11 healthy subjects. An attempt was made to determine the alterent fibers responsible for the various components by varying the stimulus intensity, by causing ischemic block of larger fibers and by estimating the afferent conduction velocities. The central pathways mediating these reflexes were examined by estimating central delays and by studying patients with focal lesions


Author(s):  
Richard E. Hartman ◽  
Roberta S. Hartman ◽  
Peter L. Ramos

The action of water and the electron beam on organic specimens in the electron microscope results in the removal of oxidizable material (primarily hydrogen and carbon) by reactions similar to the water gas reaction .which has the form:The energy required to force the reaction to the right is supplied by the interaction of the electron beam with the specimen.The mass of water striking the specimen is given by:where u = gH2O/cm2 sec, PH2O = partial pressure of water in Torr, & T = absolute temperature of the gas phase. If it is assumed that mass is removed from the specimen by a reaction approximated by (1) and that the specimen is uniformly thinned by the reaction, then the thinning rate in A/ min iswhere x = thickness of the specimen in A, t = time in minutes, & E = efficiency (the fraction of the water striking the specimen which reacts with it).


2010 ◽  
Vol 31 (3) ◽  
pp. 158-165 ◽  
Author(s):  
Thomas Boll ◽  
Tom Michels ◽  
Dieter Ferring ◽  
Sigrun-Heide Filipp

Despite its importance for basic and applied psychology, only a few longitudinal studies have examined whether parental differential treatment (PDT) is a persistent or a transient phenomenon, these studies being confined to childhood or adolescence. Based on latent state-trait theory, the present study identified the amount of variance in three dimensions of perceived PDT in middle adulthood attributable to stable interindividual differences (trait variance) and to intraindividual changes (state variance). At two occasions of measurement (2 years apart), 709 middle-aged adults rated how often they and a sibling currently received parental recognition, nurture, and demand to assume filial responsibility. Tests of latent state-trait models for these three dimensions of PDT by structural equation modeling revealed that trait variance represented the largest proportion of the systematic variance in all observed indicators of perceived maternal and paternal differential treatment. Yet there was a considerable increase in state variance for the dimension of differential parental demand for assuming responsibility. Results are discussed with respect to the conditions accounting for the high overall stability of actual and/or perceived PDT in adulthood, and different approaches for determining their role are proposed.


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