Cold-induced vasodilation and vasoconstriction in the finger of tropical and temperate indigenes

While heat acclimatization reflects the development of heat tolerance, it may weaken an ability to tolerate cold. The purpose of this study was to explore cold-induced vasodilation (CIVD) responses in the finger of tropical indigenes during finger cold immersion, along with temperate indigenes. Thirteen tropical male indigenes (subjects born and raised in the tropics) and 11 temperate male indigenes (subjects born and raised in Japan and China) participated. Subjects immersed their middle finger at 4.3±0.8 °C water for 30 min. Rectal temperature, skin temperatures, finger skin blood flow, blood pressure and subjective sensations were recorded during the test. The results showed that: (1) the tropical group demonstrated a lower minimum (T_min), maximum (T_max) and mean finger temperature (T_mean) compared to those of the temperate group (P<0.05); (2) seven tropical indigenes demonstrated a late-plateau type of CIVD pattern, which is characterized by a pronounced 1st vasoconstriction and a single CIVD with a faint and weak 2nd vasoconstriction, whereas no temperate indigene demonstrated the late-plateau type; and (3) the hand temperature at the end of finger immersion was 3 °C lower in the tropical than the temperate group (P<0.05). These results indicate that tropical indigenes have less active responses of arterio-venous anastomoses in the finger and weaker vasoconstrictions after the first CIVD response during finger cold immersion, which can be considered as being more vulnerable to cold injury of the periphery in severe cold.     

Body Site Variation of Cool Perception Thresholds,with Observations on Paradoxical Heat

Thresholds for the perception of coolness and heat pain were determined in sessions that randomly intermixed temperature increases and decreases. Four body sites were tested bilaterally: thenar eminence of the hand, plantar surface of the foot, dorsolateral forearm, and lateral calf. Coolness thresholds were lowest for the hand, intermediate for the forearm, and highest for the leg and foot. Laterality differences were not statistically significant.

In 34% of the sessions, subjects did not consistently report cool or cold sensations with detectable temperatue decreases. When they did not report cool or cold, they most often reported heat or pain, thus exhibiting the phenomenon of “paradoxical heat”. There were significantly more paradoxical heat responses when cooling stimuli were intermixed with painfully hot stimuli than when they were intermixed with only warm stimuli.

There was no significant correlation observed between thresholds for coolness and heat pain, either across body sites or across subjects at any single body site. This result implies that the various factors relevant to thermal sensitivity (i.e., thermal properties of the epidermis, innervation density) are differentially important for cool versus heat pain perception.     

Thermoregulatory behavior of the triggerfish Balistes fuscus in an electronic shuttlebox

Ten blue triggerfish,Balistes fuscus, were tested individually for 3 days each in Ichthyotron electronic shuttleboxes to measure their thermoregulatory behavior. The modal thermal preferendum, a species-specific measure of temperature preference which is independent of prior thermal acclimation, was 25 °C. The triggerfish voluntarily occupied a 16–27 °C range of temperature, out of a potentially available range of 0–50 °C. There was no significant difference in preferred temperature between night and day, indicating lack of a thermoregulatory rhythm in this species. The preferred temperature range of this tropical marine reef species is similar to that of cool temperate freshwater and marine fishes; many warm temperate species prefer higher temperatures.     

Cutaneous Warm and Cool Sensation Thresholds and the Inter-threshold Zone in Malaysian and Japanese Males

The purpose of this study was to investigate ethnic differences in cutaneous thermal sensation thresholds and the inter-threshold sensory zone between tropical (Malaysians) and temperate natives (Japanese). The results showed that (1) Malaysian males perceived warmth on the forehead at a higher skin temperature (T_sk) than Japanese males (p<0.05), whereas cool sensations on the hand and foot were perceived at a lower T_sk in Malaysians (p<0.05); (2) Overall, the sensitivity to detect warmth was greater in Japanese than in Malaysian males; (3) The most thermally sensitive body region of Japanese was the forehead for both warming and cooling, while the regional thermal sensitivity of Malaysians had a smaller differential than that of Japanese; (4) The ethnic difference in the inter-threshold sensory zone was particularly noticeable on the forehead (1.9±1.2 C for Japanese, 3.2±1.6 °C for Malaysians, p<0.05). In conclusion, tropical natives had a tendency to perceive warmth at a higher T_sk and slower at an identical speed of warming, and had a wider range of the inter-threshold sensory zone than temperate natives.     

Composition,dynamics and disturbance regime of temperate deciduous forests in Monsoon Asia

Temperate deciduous forests in Monsoon Asia are classified into three forest types which differ in floristic composition, dynamics and disturbance regime. The cool temperate mixed deciduous broadleaf/conifer forest, dominated by Quercus spp. (mainly Q. mongolica or Q. crispula) and conifers, is distributed in northern parts of the temperate zone. The cool temperate deciduous forest, dominated by Fagus crenata, is distributed in Honshu, Japan under a humid climate through the year. The warm temperate deciduous forest dominated by Quercus spp. (mainly Q. acutissima or Q. serrata) occurs in the continental areas, the Korean Peninsula, and the Pacific Ocean side of Japan. The species diversity of cool temperate deciduous forest was lower than the other two types because of the intensive dominance of Fagus crenata. The disturbance regimes also varies among the three types; small scale treefall gaps are prevailing in the cool temperate deciduous forest, while larger scaled disturbances are important in the other two forest types. Fire seems to be important in the warm temperate deciduous forest, and both fire and large scale blowdowm seems important in the cool temperate mixed broadleaf/conifer forest. These differences in forest composition and disturbance regimes associated with climatic conditions and ancient human impacts have a close analogy with the Northeastern Hardwood forests in North America.     

World-wide latitudinal and longitudinal seaweed distribution patterns and their possible causes,as illustrated by the distribution of Rhodophytan genera

The degree of similarity between red algal generic floras in each pair of 22 climatically defined biogeographic regions was established on a world-wide scale by Jaccard's similarity index and by an hierarchical clustering with an agglomerative centroid method. Two clusterings were carried out, the first one on the basis of all 637 genera, and the second one on the basis of genera not occurring in the tropics and non-endemic to any one of the 22 regioms (145 genera). This latter clustering served to detect better the relationships among non-tropical floras. The results indicate the following division of the earth's rhodophytan seaweed floras: (1) A rich tropical-warm temperate "Tethyan" group including the rich tropical Indo W Pacific and W Atlantic floras, and the rich warm temperate NW Pacific and NE Atlantic floras; (2) the depauperate extensions of the above group (the tropical E Pacific and E Atlantic floras, and the warm temperate NW and SW Atlantic floras); (3) a cold temperate and a warm temperate N Pacific group; (4) an Arctic-cold temperate N Atlantic group and a NE Atlantic warm temperate flora; (5) an Antarctic-cold temperate southern hemisphere group including the cold temperate SE Pacific, SW Atlantic, SE Atlantic floras, and the Antarctic flora; (6) the two highly individual, but slightly related warm temperate SE Atlantic flora (S. Africa) and SW Pacific flora (Southern Australia and Northern New Zealand); (7) the depauperate warm temperate SE Pacific flora. Although the northern and southern hemisphere temperate and polar floras are quite unrelated (on the basis of genera lacking in the tropics), they share nonetheless a number of cool water genera which apparently have succeeded in passing the adverse tropical belt. The rich tropical-warm temperate group is thought to consist of vicariant portions of a formerly continuous Tethyan flora. The N Pacific and N Atlantic temperate floras are thought to have developed independently since the Oligocene (~ 40.10⁶ y) deterioration of the climate and to have partially mixed their cool water genera only after the Pliocene inundation (2.10⁶ y) of the Bering Land Bridge. The warm-temperate floras of S Africa and southern Australia probably owe their richness and individuality to a very long isolation (already at the start of the Cenozoicum) and a continued residence in warm temperate conditions with small seasonal fluctuations.Paper presented at the Seaweed Biogeography Workshop of the International Working Group on Seaweed Biogeography, held from 3–7 April 1984, at the Department of Marine Biology, University of Groningen (The Netherlands). Convenor: C. van den Hoek.     

Occurrence of the Chilean devil ray Mobula tarapacana (Elasmobranchii: Batoidea: Myliobatiformes) in the Sea of Okhotsk: first record from cold temperate waters

The northernmost record for Chilean devil ray Mobula tarapacana, a circumglobal species that occurs in tropical, subtropical and limited warm temperate waters, is described. An adult female was caught incidentally in the Sea of Okhotsk on 17 September 2011. This specimen is the first confirmed occurrence of devil rays Mobula spp. in cold temperate waters.     

Seaweed biogeography of the mid-Atlantic coast of the United States

The northern boundary of the warm temperate region of the mid-Atlantic coast of the United States is set at Cape Hatteras; the southern boundary lies at Cape Canaveral. There is some spillover of cool temperate species south of Cape Hatteras into North Carolina and spillover of warm temperate species south of Cape Canaveral toward Palm Beach. Elements of the warm temperate flora also extend into the northern Gulf of Mexico, but precise limits to the flora cannot be drawn there. Thirty-one species are endemic to the warm temperate flora. The inshore waters of North Carolina include approximately equal numbers of species with northern and southern centres of distribution; the species of the offshore waters have predominantly southern affinities, but also include most of the endemic species. Seasonal changes in the shallow water flora of North Carolina reflect eurythermal cool temperate and tropical elements in winter and summer respectively and a year-round warm temperate element. These groupings have been verified by experimental studies in which light and temperature were varied. The deep water flora is a summer flora dominated by perennial species. The inshore, eurythermal cool temperate and tropical species have a variety of cryptic stages by which they persist throughout the year.Paper presented at the Seaweed Biogeography Workshop of the International Working Group on Seaweed Biogeography, held from 3–7 April 1984 at the Department of Marine Biology, Rijks-universiteit Groningen (The Netherlands). Convenor: C. van den Hoek.     

Latitudinal biodiversity patterns of meiofauna from sandy littoral beaches

Meiofaunal samples from arctic (Bear Island, Franz Josef Land, Hopen, Kolguev), temperate (Baltic Sea, North Sea), subtropical (Tunisia, Greece), tropical (Emirates, Ghana) and antarctic sandy beaches were collected at the medium water mark. The highest average meiofaunal density was found in the temperate zone (1300 individuals 10 cm^–2) and the lowest in both polar regions: in arctic (79 individuals 10 cm^–2) and in antarctic (35 individuals 10 cm^–2) samples. Nematodes dominated the meiofauna community in warm regions, while turbellarians were more common in cold water regions. Sixteen higher taxa were recorded in tropical sites, while only eight taxa were observed in the sampled cold regions. This difference was mainly due to the presence of small specimens of macrofauna in the tropics. When only true meiofauna higher taxa were compared, no latitudinal trends were found.     

Palynology of a 250-m core from Lake Biwa: a 430,000-year record of glacial–interglacial vegetation change in Japan

Lake Biwa is situated in western Honshu, and is the largest and oldest freshwater lake in Japan. During 1982–1983, a long core was drilled to a bottom depth of 1422 m in order to investigate the palaeolimnological record, which contains 911 m of various sedimentary units overlying Palaeozoic–Mesozoic basements. A 249.5-m core of the uppermost bed (T Bed) was palynologically examined at intervals of ca. 2 m. The investigated part of the core covers approximately the last 430,000 years of the mid-Upper Pleistocene and Holocene, and five glacial–interglacial cycles can be recognized. Ten major vegetational zones could be recognized from the bottom to the surface. The zones bearing even numbers, BW-10, 8, 6, 4 and 2, matched glacial periods in which pollen of subarctic taxa (Pinaceae, Betula) and cool–temperate taxa (Fagus, Lepidobalanus) was dominant. In the glacial periods, high pollen values for temperate conifers such as Cryptomeria, Cupressaceae and Sciadopitys indicate interstadial periods. Zones bearing odd numbers, BW-9, 7, 5, 3 and 1, matched interglacial periods with high pollen values for the warm–temperate taxon Cyclobalanopsis, or showed the characteristic appearance of Lagerstroemia, and temperate coniferous taxa (Cryptomeria, Cupressaceae). There were two vegetational types in the interglacial periods. One was the type indicated by BW-9 and 1 zones, when warm–temperate evergreen broad-leaved trees such as Cyclobalanopsis and Castanopsis showed high pollen values, and the warm–temperate deciduous broad-leaved tree Lagerstroemia was lacking. The climate of these interglacial periods seems to have been cold and dry in winter, and warm and wet in summer. The other was the vegetational type recorded in BW-7, 5 and 3 zones, where Lagerstroemia showed low pollen values, and the warm–temperate evergreen broad-leaved trees mentioned above were poorly represented. The climate seems to have been mild and wet in winter, and cool and wet in summer. The dominant pollen values for cool–temperate deciduous broad-leaved taxa such as Fagus and Lepidobalanus are very important indicators of the initiation of both glacial and interglacial periods in western Japan.     

Age-related differences in cutaneous warm sensation thresholds of human males in thermoneutral and cool environments

The purpose of this study was to investigate age-related differences in cutaneous temperature thresholds for warm thermal sensitivity in a thermoneutral (28 °C) and in a cool environment (22 °C). Peripheral warm thresholds were measured on nine body regions (cheek, chest, abdomen, upper arm, forearm, hand, thigh, shin, and foot) using a thermal stimulator in 12 young (22±1 years) and 13 elderly male subjects (67±3 years). The results showed that: (1) mean skin temperature did not differ by age in both environments; (2) the cutaneous warm thresholds for the hand, shin, and foot were significantly higher for the elderly than for the young in both environments (p<0.01), whereas the remaining body parts showed no age difference; (3) the most insensitive region for elderly males was the shin for both environments (p<0.01), while for young there was no statistical significant difference with T_a 28 °C; (4) the shin of the elderly was seven and nine times less sensitive to warmth when compared to those of the cheek at T_a 28 and 22 °C, respectively; and (5) warm thresholds were 3-4 °C greater at T_a 22 °C than at 28 °C, only for the elderly males' shin and foot (p<0.05), while for young the difference between T_a 22 and 28 °C was not statistically significant. The results indicate that age-related differences in cutaneous warm perception appear to be non-uniform over the body and significant on extremities; there is a greater bluntness of warm sensitivity in the cool environment for elderly males.     

Reliability of the method of levels for determining cutaneous temperature sensitivity

Determination of the thermal thresholds is used clinically for evaluation of peripheral nervous system function. The aim of this study was to evaluate reliability of the method of levels performed with a new, low cost device for determining cutaneous temperature sensitivity. Nineteen male subjects were included in the study. Thermal thresholds were tested on the right side at the volar surface of mid-forearm, lateral surface of mid-upper arm and front area of mid-thigh. Thermal testing was carried out by the method of levels with an initial temperature step of 2°C. Variability of thermal thresholds was expressed by means of the ratio between the second and the first testing, coefficient of variation (CV), coefficient of repeatability (CR), intraclass correlation coefficient (ICC), mean difference between sessions (S1-S2diff), standard error of measurement (SEM) and minimally detectable change (MDC). There were no statistically significant changes between sessions for warm or cold thresholds, or between warm and cold thresholds. Within-subject CVs were acceptable. The CR estimates for warm thresholds ranged from 0.74°C to 1.06°C and from 0.67°C to 1.07°C for cold thresholds. The ICC values for intra-rater reliability ranged from 0.41 to 0.72 for warm thresholds and from 0.67 to 0.84 for cold thresholds. S1-S2diff ranged from -0.15°C to 0.07°C for warm thresholds, and from -0.08°C to 0.07°C for cold thresholds. SEM ranged from 0.26°C to 0.38°C for warm thresholds, and from 0.23°C to 0.38°C for cold thresholds. Estimated MDC values were between 0.60°C and 0.88°C for warm thresholds, and 0.53°C and 0.88°C for cold thresholds. The method of levels for determining cutaneous temperature sensitivity has acceptable reliability.     

Cold and heat tolerance of drosophilid flies with reference to their latitudinal distributions

The relation between thermal tolerance and latitudinal distribution was studied with 30 drosophilid species collected from the cool-temperate region (Sapporo), the warm-temperate region (Tokyo and Kyoto) and the subtropical region (Iriomote island) in Japan. In addition, intraspecific variation was examined for five species collected from two localities. The subtropical strains of Scaptodrosophila coracina, Drosophila bizonata and D. daruma were less tolerant to cold than their temperate strains. However, the difference of cold tolerance between these two geographic strains was much smaller than the difference between the species restricted to the subtropical region and those occurring in the temperate region. In D. auraria and D. suzukii, no difference was observed in thermal tolerance between their cool- and warm-temperate strains. Thus, geographic variation in thermal tolerance within species was low or negligible. Interspecific comparisons by phylogenetic independent contrasts revealed that species which had the northern boundaries of their distributions at higher latitudes were generally more tolerant to cold than those which had their boundaries at lower latitudes. However, the data for some species did not agree with this trend. The use of man-protected warm places for overwintering, competition or predation would also affect their distributions. It also appeared that species which had their southern boundaries at higher latitudes were generally more cold-tolerant. The acquisition of cold tolerance may lower a flys capacity to compete, survive or reproduce in warmer climates. On the other hand, no relation was observed between heat tolerance and latitudinal distribution. Heat tolerance was higher in species inhabiting openlands or the forest canopy than in those inhabiting the forest understorey.     

Comparison of unpleasant and pain thresholds of thermal stimuli in the orofacial regions: a psychophysical study using quantitative sensory testing in healthy young men

Abstract

Purpose/Aim: To gain a better understanding of the psychophysics of thermal pain perception in a clinical setting, this study investigated whether thermal thresholds of unpleasantness are different from pain thresholds of cold and heat stimuli. Of particular interest was the relationship between unpleasantness and pain thresholds for cold vs heat stimuli.

Material and methods: Thirty healthy male volunteers (mean age 26.1?years, range 23 to 32?years) participated. Thermal detection, cold pain (CPT) and heat pain (HPT) thresholds were measured at 5 trigeminal sites by the method of limits using quantitative sensory testing (QST), followed by cold unpleasant (CUT) and heat unpleasant (HUT) thresholds.

Results: The temperatures at which individuals first reported thermal sensations as unpleasant or painful substantially differed among subjects. CUT exhibited a higher mean value with less variability than CPT, and HUT presented a lower mean than HPT (p?<?.001). As with CPT, CUT did not show any significant difference between the test sites. On the other hand, HUT, like HPT, exhibited site differences (p?<?.001). There was moderate correlation between CUT and CPT, whereas HUT and HPT were strongly correlated. The relationship between unpleasant and pain thresholds of cold vs heat stimuli was significantly different even when controlling for test site variability (p?<?.001).

Conclusion: These findings indicate that unpleasant and pain thresholds to thermal stimuli differ in healthy young men. Of particular note is the distinct relationship of unpleasant and pain thresholds of cold vs heat stimuli, revealing the thermal difference in temperature transition from unpleasantness to pain.     

An altitudinal transect study of the vegetation on Mount Kinabalu,Borneo

A quantitative transect analysis of altitudinal sequences of forest canopy species from 600 to 3400 m asl on Mt. Kinabalu (4101 m), Borneo, resulted in four discrete altitudinal vegetation zones. These were made up of mutually exclusive species groups for lowland (<1200 m asl), lower montane (1200 to 2000–2350 m asl), upper montane (2000–2350 to 2800 m asl), and subalpine (2800 to the forest line, 3400 m asl) zones. Zonal soil types were correlated with the vegetation zones. In upslope sequence, these were: lowland Oxisols, montane Histosol/Spodosol complex, and subalpine Inceptisols. The highest contents of organic carbon, extractable phosphorus, and exchangeable magnesium and potassium were recorded in the lower and upper montane zones. The upper boundaries of the lowland, upper montane and subalpine zones coincided with thermal thresholds of latitudinal bioclimatic zones: 18°C TMIN (Köppen's tropical), WI 85 (Kira's warm temperate), and WI 45 (Kira's cool temperate), respectively. The upper limit of the lower montane zone was correlated with an abrupt increase of water surplus estimated from the annual rainfall minus annual potential evaporation. These climatic characteristics appear to define ecological altitudinal turnover points, so called critical altitudes, where groups of associated species are displaced by other groups.Abbreviations asl = above sea level - DBH = diameter at breast height - PHQ = Park headquarters - TMAX = Mean daily maximum air temperature - TMIN = Mean daily minimum air temperature - TWINSPAN = Two-way indicator species analysis - WI = Warmth index     

A correlation between photosynthetic temperature adaptation and seasonal phenology patterns in the shortgrass prairie

Summary The temperatures at which chlorophyll fluorescence yield is substantially increased and the temperatures at which the quantum yield for CO₂ uptake is irreversibly inhibited were measured for three shortgrass prairie species. The experimental taxa include, a cool season species (Agropyron smithii), a warm season species (Bouteloua gracilis), and a species which grows throughout the cool and warm seasons (Carex stenophylla). Agropyron smithii exhibited lower high temperature damage thresholds (43°C in cool grown plants, 46°C in warm grown plants), relative to the other two species. Bouteloua gracilis exhibited the highest tolerance to high temperature, with threshold values being 44–49°C for cool grown plants and 53–55°C for warm grown plants. Carex stenophylla exhibited threshold values which were intermediate to the other two species (43–47°C for cool grown plants, and 51–53°C for warm grown plants). Seasonal patterns in the fluorescence rise temperatures of field grown plants indicated acclimation to increased temperatures in all three species. The results demonstrate a correlation between the high temperature thresholds for damage to the photosynthetic apparatus, and in situ seasonal phenology patterns for the three species.     

A comparison of the responses of tropical and temperate flies (Diptera: Sarcophagidae) to cold and heat stress

Summary Two flesh fly species from the tropical lowlands (Peckia abnormis and Sarcodexia sternodontis) were more susceptible to both cold-shock and heatshock injury than temperate flies (Sarcophaga crassipalpis and S. bullata) and a fly from a tropical high altitude (Blaesoxipha plinthopyga). A brief (2-h) exposure to 0°C elicits a protective response against subsequent cold injury at–10°C in the temperate flies and in B. plinthopyga but no such response was found in the flies from the tropical lowlands. However, both tropical and temperate flies could be protected against heat injury (45°C) by first exposing them to a mild heat shock (2 h at 40°C). The supercooling point is not a good indicator of cold tolerance: supercooling points of pupae were similar in all species, ranging from–18.9 to–23.0°C, and no differences were found between the tropical and temperate species. Among the temperate species, glycerol, the major cryoprotectant, can be elevated by short-term exposure to 0°C, but glycerol could not be detected in the tropical flies. Low-temperature (0°C) exposure also increased hemolymph osmolality of the temperate species, but no such increase was observed in the tropical lowland species. Adaptations to temperature stress thus differ in tropical and temperate flesh flies: while flies from both geographic areas share a mechanism for rapidly increasing heat tolerance, only the temperate flies appear capable of responding rapidly to cold stress. The presence of a heat shock response in species that lack the ability to rapidly respond to cold stress indicates that the biochemical and physiological bases for these two responses are likely to differ.     

The thermal mismatch hypothesis explains host susceptibility to an emerging infectious disease

Parasites typically have broader thermal limits than hosts, so large performance gaps between pathogens and their cold‐ and warm‐adapted hosts should occur at relatively warm and cold temperatures, respectively. We tested this thermal mismatch hypothesis by quantifying the temperature‐dependent susceptibility of cold‐ and warm‐adapted amphibian species to the fungal pathogen Batrachochytrium dendrobatidis (Bd) using laboratory experiments and field prevalence estimates from 15 410 individuals in 598 populations. In both the laboratory and field, we found that the greatest susceptibility of cold‐ and warm‐adapted hosts occurred at relatively warm and cool temperatures, respectively, providing support for the thermal mismatch hypothesis. Our results suggest that as climate change shifts hosts away from their optimal temperatures, the probability of increased host susceptibility to infectious disease might increase, but the effect will depend on the host species and the direction of the climate shift. Our findings help explain the tremendous variation in species responses to Bd across climates and spatial, temporal and species‐level variation in disease outbreaks associated with extreme weather events that are becoming more common with climate change.     

Effect of thermal stress on the neurosecretory cells of the freshwater prawn,macrobrachium kistnensis (Tiwari)

The brain and thoracic ganglion neurosecretory cells of the freshwater prawn, M. kistnensis displayed characteristic changes following 24 hr exposure to warm (31.0° ± 0.5°C) and cold (13.0° ±0.5°C) stress. A and B cells from the brain showed significant elevation in their nuclear diameters after warm and cold stress. Warm stress depressed whereas cold stress enhanced the neurosecretory material intensity of A cells. However, the intensity of B cells neurosecretory material remained unaltered following both treatments. On the contrary nuclear diameters of both A and B neurosecretory cell significantly decreased and an increment in neurosecretory material intensity was revealed in the thoracic ganglion of both warm and cold stressed prawns.