Ruth Nielsen

Measurement of mean skin temperature of clothed persons in cool environments

SummaryThe precision with which mean skin temperature could be estimated from some few points on clothed persons in a cool environment was studied. The skin temperature data were obtained from experiments on 10 clothed persons who were resting and working at an environmental temperature of 10‡ C. With these data, eleven calculation formulas in current use were compared to a “reference mean skin temperature” based on a weighting formula involving 13 local skin temperatures.It was concluded that no formula including less than seven points gave a reasonably accurate mean skin temperature in this cool environment. In addition, a stepwise correlation analysis involving linear regression was performed on the data. This gave 12 new calculation formulas, which were evaluated for accuracy in estimating mean skin temperature. Among these, a weighting formula involving only four local skin temperatures was selected to be recommended for use in field investigations:

Influence of skin temperature distribution on thermal sensation in a cool environment.

\begin{gathered} \bar T_{sk} = 9.429 + 0.137 x T_{forehead} + 0.102 x T_{hand} \hfill \\ + 0.290 x T_{lower back} + 0.173 x T_{lower leg} . \hfill \\ \end{gathered}

A comparative study of five marine Chaetophoraceae

The occurrence of three endophytic green algae within Chondrus crispus Stackh. is reported. Two of them are new to science and are described as Acrochaete heteroclada Correa and Nielsen sp. nov. and A. operculata Correa and Nielsen sp. nov. The algae were studied in unialgal culture and in association with the host following infection of C. crispus under laboratory conditions. The experimental infection showed A. heteroclada to be initially epiphytic, with endophytic filaments growing into the cortex of the host during late infection. A. operculata is entirely endophytic when associated with the host. Phaeophila dendroides (Crouan frat.) Batters behaves as an epiphyte at 15 and 24°C but penetrates the host tissues at 20°C. For all three species, a close physical association with the host is established only when zoospores settle and germinate on the surface of C. crispus.

Culture studies on Ulvella lens and Ulvella setchellii

SummaryThermal sensation and distribution of skin temperatures in persons exercising at 36.5 W on a bicycle ergometer and resting in a cool environment (10‡ C) in two different clothings, one with the insulation mainly over the trunk (1.22 clo), and one with well insulated limbs (1.67 clo), were studied. Their general thermal sensations varied from slightly warm to slightly cool. The placing of the insulation had a decisive influence on skin temperature distribution, so that skin temperature was always high in well-insulated areas. When the insulation was placed over the limbs, a greater amount of heat was lost than if a similar insulation was placed on the trunk. Neither

VARIATION IN OCHLOCHAETE HYSTRIX (CHAETOPHORALES. CHLOROPHYYCEAE) STUDIED IN CULTURE1

\bar T_{sk}