The calculation from weather records of the requirement for clothing insulation

Standard meteorological measurements of dry bulb temperature, wind speed, sunshine, cloud cover and rainfall are used to calculate the clothing insulation required by man for thermal comfort under given weather conditions. The calculation is based on earlier work on the effect of weather on sensible (non-evaporative) heat loss from sheep, which used the relation between heat flow, thermal insulation and the difference between body and environmental temperatures.Clothing insulation for man is estimated in two ways: as clothing (I_c) that is impervious to the effects of wind and rain; and as the equivalent depth of sheep fleece (f_m), which is not impervious. This allows the assessment of wind chill for a range of clothing of varied penetration by wind instead of for only one type of garment.Results are given as daily means calculated from hourly measurements throughout 1973 for Plymouth (on the south coast of Britain) and Aberdeen (on the far northeast coast of Britain). Wind chill is estimated both by its effect on f_m requirement and by the fall in air temperature that would be needed to produce under still-air conditions the same demand for f_m that occurs in the actual environment. The monthly mean f_m requirement is reduced by about 40% when the effect of wind is removed. When wind chill is estimated as an equivalent fall in air temperature it approximates to 1 K per knot wind speed measured at the standard meteorological height of 10 m.     

Hypertension associated with neurocognitive performance among persons with type 2 diabetes: a brief report

Background Among persons with type 2 diabetes (T2DM) it is not known whether the presence of hypertension could have a detrimental effect on learning ability and whether repeated exposure to information changes the amount of information retained. The aim of this study was to determine cross-sectional evidence for a differential burden to cognitive functioning among persons with T2DM and comorbid hypertension (HTN).Methods This study performed a cross-sectional, retrospective analysis, by medical chart review, of patients with a diagnosis of T2DM.Results Medical records information for history of HTN, age, gender and cognitive performance scores were recorded and analysed for 112 T2DM patients, with an average age of 60 years (SD = 13.84). Differences in cognitive performance scores were compared between patients with and without a history of HTN. The results show that participants who were diagnosed with hypertension produced lower average Rey Auditory–Verbal Learning Test scores than individuals who are not diagnosed with hypertension. Trial 2 was the only trial to prove significant with a P-value of 0.041.Conclusions Our results support previous studies showing that HTN is associated with increased risk to learning and memory functioning, although the degree of interference with these cognitive functions could not be determined from our research. Recognising that people diagnosed with HTN may be at risk for poorer learning and memory skills, future research can investigate how the length of time with the diseases affects learning and memory, and how medication management can attenuate cognitive learning and memory performance.     

Acclimation or stress symptom? An integrated study of intraspecific variation in the clonal plant Aechmea bromeliifolia,a widespread CAM tank‐bromeliad

The clonal tank-bromeliad Aechmea bromeliifolia (Rudge) Baker was found in four different habitats in a restinga (vegetation mosaic on sandy coastal plains), of south-eastern Brazil. These habitats (swamp forest, dry forest, dry shrubland and herbaceous marsh) lie within a few hundred metres of each other along a gradient extending inland from the coast, and differ markedly in terms of light and flood regime. We compared ramet morphology, leaf anatomy and physiology, and population parameters to examine the amplitude of trait variation of this widespread species in the studied restinga. This integrated approach allowed us to examine which variation conferred acclimation and which was merely a stress symptom. A . bromeliifolia showed site-specific differences in abundance, distribution, rosette size and shape, leaf anatomical arrangement and photochemical efficiency (potential quantum yield; F _v/ F _m) during the day. Most of the variation found seemed to be related to the interaction of light and flooding. The lowest number and size of ramets at the exposed, dry shrubland was matched by a marked leaf photoinhibition, which suggested poor acclimation to local levels of light intensity and limited water supply. In the other habitats, the morpho-physiological parameters measured suggested adequate foraging behaviour and site acclimation.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society, 2002, 140 , 391-401.