Magnetic signature of environmental change reflected by Pleistocene lacustrine sediments from the Nihewan Basin, North China

A mineral magnetic study has been conducted on Pleistocene lacustrine sediments from the Xujiayao Paleolithic site within the Nihewan Basin, North China. The magnetic signal is characterized by a dominance of high-coercivity (hematite) minerals that is modulated by low-coercivity magnetite–maghemite assemblages during interglacials. A high-amplitude record of the composition dependent magnetic S_− 0.3 T-parameter varies in accord with composite marine oxygen isotope records, suggesting climate modulation of magnetic composition. The Xujiayao site is situated at the northern outskirts of the Chinese Loess Plateau (CLP) and has neither received significant eolian input nor been exposed to pedogenic processes comparable to those acting on CLP. Mineral magnetic analyses suggest that variations in both magnetite and hematite are primarily controlled by detrital fluxes rather than by authigenic production of magnetic minerals. Here we propose that the fluctuations of magnetic signals at Xujiayao are not derived from varying compositions of eolian flux with glacial/interglacial periods or minute eolian influx during interglacials, but is likely dominated by runoff-related processes, by which some weathered/pedogenized loess and soils with stronger magnetic signals have been eroded and transported to the catchment during interglacials resulting in magnetic enhancement. The inferred continuous deposition from the Brunhes/Matuyama boundary to the paleosol S₁ (ca. 129 ka) gives the age of ca. 500 ka for the sediments carrying the Xujiayao Paleolithic site, suggesting an allogenic origin of the Paleolithic artifacts and mammalian bones dated by U–Th method to ca. 100 ka.     

Continuous-flow complete-mixing system for assessing the effects of environmental factors on colony-level coral metabolism

A small-scale chamber experimental system was designed to study the effects of temperature on colony-level coral metabolism. The system continuously supplies fresh seawater to the chamber, where it is mixed immediately and completely with the seawater already present. This continuous-flow complete-mixing system (CFCM system), in conjunction with theoretical equations, allows quantitative determination of chemical uptake and release rates by coral under controlled environmental conditions. We used the massive hermatypic coral Goniastrea aspera to examine variations in pH, total alkalinity, and total inorganic carbon for 16 days at 27 °C under controlled light intensities (300 and 0 µmol m^− 2 s^− 1). We confirmed the stability of the CFCM system with respect to coral photosynthetic and calcification fluxes. In addition, we obtained daily photosynthetic and calcification rates at different temperatures (27 °C, 29 °C, 31 °C, and 33 °C). When seawater temperature was raised from 31 °C to 33 °C, the gross primary production rate (P_gross) decreased 29.5%, and the calcification rate (G) decreased 85.7% within 2 days. The CFCM system allows quantitative evaluation of coral colony chemical release and uptake rates, and metabolism.     

Climatic conditions in Southern Africa since the last glacial maximum, inferred from pollen analysis

A review of Late Quaternary palaeoclimatic data derived from several pollen sequences, between ca. 22 and 34°S in Southern Africa, shows a degree of similarity in temperature and moisture variations between the various site. Pollen data from sites such as Wonderkrater and Rietvlei (Transvaal), Tate Vondo (Venda), Elim (Orange Free State), Equus Cave (Southern Kalahari) and Boomplaas (Cape Province) suggest relative dryness during the Last Glacial Maximum, wet conditions during the Late Glacial, and dry conditions during the Early Holocene ca. 8000 yr B.P., followed by progressively moister conditions peaking soon after the development of a temperature optimum ca. 6500 yr. B.P. Problems with radiocarbon dating of polleniferous spring deposits, however, prevent precise correlations of especially Late Pleistocene sequences. Different seasonal patterns in the Late Glacial and Early Holocene may explain palaeobotanical data and are partly compatible with simulations of past climates of Kutzbach and Guetter (1986).     

A Late Triassic lake system in East Greenland: facies, depositional cycles and palaeoclimate

The Upper Triassic Fleming Fjord Formation of the Jameson Land Basin in East Greenland contains a well-exposed succession, 200–300 m thick, of lake deposits. The Malmros Klint Member, 100–130 m thick, is composed of cyclically bedded intraformational conglomerates, red siltstones and fine-grained sandstones and disrupted dolomitic sediments (paleosols). The cyclicity is composite with cycles having mean thicknesses of (25), 5.9 and 1.6 m. The overlying Carlsberg Fjord beds of the Ørsted Dal Member, 80–115 m thick, are composed of structureless red mudstones rhythmically broken by thin greyish siltstones. This unit also has a composite cyclicity with cycles having mean thicknesses of 5.0 and 1.0 m. The uppermost Tait Bjerg Beds of the Ørsted Dal Member, 50–65 m thick, can be divided into two units. A lower unit is composed of cyclically bedded intraformational conglomerates or thin sandstones, red mudstones, greenish mudstones and yellowish marlstones. An upper unit is composed of relatively simple cycles of grey mudstones and yellowish marlstones. Recognized cycles have mean thicknesses of 5.6 and 1.6 m. The lake deposits contain evidence of seasonal, orbital and long-term climatic change. Seasonal change is documented by numerous desiccation surfaces especially in the Malmros Klint Member and Carlsberg Fjord beds, orbital change is suggested by the composite cyclicity, and long-term climatic change is indicated by the systematic upwards change in sedimentary characteristics of the lake deposits. The sedimentary features of the Malmros Klint Member suggest lacustrine deposition in a dry climate that fluctuated between desert and steppe conditions, the Carlsberg Fjord beds probably record lacustrine lake deposition in a rather constant dry (steppe) climate, while the Tait Bjerg Beds record lake sedimentation in a climate that fluctuated between dry (steppe) and warm moist temperate. In the Tait Bjerg Beds the upward change in cycle characteristics indicates a shift towards more humid conditions. Climatic deductions from sedimentary facies are in good agreement with climate maps of Laurasia, as simulated by numerical climate models. Palaeomagnetic data indicate a northward drift of East Greenland of about 10° from ca. 25°N to ca. 35°N in the Middle to Late Triassic. The Fleming Fjord Formation which represents ca. 5 m.y. of the Late Triassic interval was deposited during latitudinal drift of 1–2°. It is possible that the observed long-term upward shift in climatic indicators within the formation can be ascribed to plate drift, but southward shift of climatic belts could also have been of importance.     

Morphology and germination characteristics of the cysts of Chattonella ovata (Raphidophyceae), a novel red tide flagellate in the Seto Inland Sea, Japan

To elucidate the mechanism of bloom outbreaks of Chattonella ovata (Raphidophyceae), we investigated the cysts of C. ovata and succeeded in finding them from the bottom sediments of Hiroshima Bay. The morphology of the cysts was mostly hemispherical in shape, with a diameter of ca. 30 μm and height of ca. 20 μm. The cysts were usually adhering to solid materials, such as diatom frustules, yellow-greenish in color and had several dark brown grains. The cyst wall was smooth and had no ornamentation. Because the morphological characteristic of the cysts was in general agreement with those of Chattonella antiqua and Chattonella marina, it was difficult to differentiate the cysts of these three species. Germination of the cysts of C. ovata was observed at temperatures from 17.5 to 30 °C, but not at 15 °C or below. The number of the germinated cysts increased with increasing temperature and the optimum temperature for germination was 30 °C. Although cysts of C. antiqua and C. marina germinated at temperatures from 15 to 30 °C, optimum temperature of germination was 22.5 °C. The lower limit and optimum temperatures for germination of C. ovata cysts was higher than for C. antiqua and C. marina. The role of cysts in the population dynamics of C. ovata is discussed.     

Determination of the thermodynamics of carbonic anhydrase acid-unfolding by titration calorimetry

The enthalpy of unfolding (Δ_uH) of carbonic anhydrase II was determined by titrating the protein with acid and measuring the heat using isothermal titration calorimetry (ITC) in the temperature range of 5 to 59 °C. By combining the ITC results with our previous findings by differential scanning calorimetry (DSC) in the temperature range of 39 to 72 °C, the Δ_uH dependence over a wide temperature range was obtained. The temperature dependence of the enthalpy displays significant curvature indicating that the heat capacity of unfolding (Δ_uC_p) is dependent on temperature. The T-derivative of Δ_uC_p was equal to 100 ± 30 J/(mol × K²), with the result that the Δ_uC_p is equal to 15.8 kJ/(mol × K) at 5 °C, 19.0 kJ/(mol × K) at 37 °C and 21.8 kJ/(mol × K) at 64 °C. The enthalpy of unfolding is zero at 17 °C. At lower temperatures, the Δ_uH becomes exothermic.

This method of determining protein unfolding thermodynamics using acid-ITC, significantly widens the accessible T-range, provides direct estimate of the thermodynamic parameters at physiological temperature, and gives further insight into the third T-derivative of the Gibbs free energy of unfolding.     

Effect of propranolol and cold exposure on the activities of antioxidant enzymes in the brain of rats adapted to different ambient temperatures

The exposure to cold (6 h; 6°C) induced a significant decrease in both hypothalamic and brain stem CuZn-superoxide dismutase as well as an increase in Mn-superoxide dismutase and catalase activities in Wistar male rats, acclimated to 6±1°C as compared to those acclimated to 22±2°C. If the rats were administered with propranolol (15 mg/kg), which is a β-adrenoceptor blocker, there were no significant differences in the enzyme activities in any of the brain regions of the two groups studied. It was concluded that acute exposure to cold induces changes in the hypothalamic and brain stem antioxidant enzyme activities dependent on the previous acclimation to different ambient temperatures and propranolol administration.     

Upper quaternary vegetational and climatic sequence of the fuquene area (Eastern Cordillera,Colombia)

In this paper the results of a pollen-analytical study of three bore holes of lake deposits in the Fuquene-Valle de Ubaté area, Colombian Cordillera Oriental (5° N; elev. 2,580 m) are given. By means of ¹⁴C dates and comparison with other pollen diagrams and dates from the Eastern Cordillera, it was possible to correlate the local pollen zones and chronostratigraphical units with the European chronostratigraphical sequence. The longest diagram (Fuquene II) represents some 30, 000 years, including part of the Middle Pleniglacial, the Upper Pleniglacial, the Late Glacial and the Holocene.During the Middle Pleniglacial, Polylepis wood was an important constituent of the vegetation. During climatic extremes of the Upper Pleniglacial an open páramo vegetation existed.During the main part of the Upper Pleniglacial (from ca. 21,000 to ca. 13,000 B.P.) the lake level was low and the climate dry. The lake level rose again in the beginning of the Late Glacial, and the area around the lake became forested. At the beginning of the El Abra Stadial (Late Dryas Stadial) there was a marked cooling and the lake became lower once more; this had a great impact on the vegetation which became partly open again. The beginning of the Holocene is marked by a gradual increase of forest elements, especially of Quercus (oak.) Oak forests dominated the area during the greater part of the Holocene. During the “hypithermal”, elements growing today at a lower level, such as Cecropia, Acalypha (and possibly Alchornea), must have been growing in the area, intermixed with the oak forest. At the same time there was a considerable increase of Urticaceae in the undergrowth of these forests. The vegetation zones were probably situated several hundreds of metres higher than they are at the present time.The influence of man on vegetation had started already before the beginning of our era, but there is a sudden increase of this influence (e.g., increase of Dodonaea, decrease of Quercus and Urticaceae) somewhere around 2,000 B.P. Later on, the diagram shows the rapid ultimate decline of the forest elements and an increase of Gramineae. Today nothing is left of the original oak forests and their place is taken by arable land or by secondary plant communities with low brushwood.In the lake sediments, thin layers of volcanic ash were found dated approximately 9,000 B.P., 11,000 B.P., and 21,000 B.P., respectively; a series of three ash-layers was deposited between approximately 22,000 B.P. and 26,000 B.P. and one possibly at approximately 30,000 B.P. These layers have been found in several other sections in the Eastern Cordillera and are the basis for a tephrochronology.     

Freezing resistance improvement of Lactobacillus reuteri by using cell immobilization

Lactobacillus reuteri shows certain beneficial effects to human health and is recognized as a probiotic. However, its application in frozen foods is still not popular because of its low survival during freezing and frozen storage. Cell immobilization technique could effectively exert protection effects to microbial cells in order to enhance their endurance to unfavorable environmental conditions as well as to improve their viability and cell concentration. Ca-alginate and κ-carrageenan were used to immobilize L. reuteri in this research, and the immobilized cells were exposed to different freezing temperatures, i.e. − 20 °C, − 40 °C, − 60 °C, − 80 °C, and stored at − 40 °C and − 80 °C for 12 weeks. The objectives were to study the protection effects of cell immobilization against the adverse conditions of freezing and frozen storage, and the effects of freezing temperatures to the immobilized cells. Cell immobilization was used to raise the survival of L. reuteri during freezing and frozen storage in order to develop frozen foods with the probiotic effects of L. reuteri. Results indicated that immobilized L. reuteri possessed better survival in both freezing and frozen storage. The survival of immobilized L. reuteri was higher than that of free cells, and the effects of lower freezing temperature were better than higher freezing temperature. The immobilization effects of Ca-alginate were found to be superior to κ-carrageenan. Cell immobilized L. reuteri exhibits potential to be used in frozen foods.     

Effects of temperature, photoperiod, and light intensity on the eclosion rhythm of the high-altitude Himalayan strain of Drosophila ananassae

Eclosion rhythm of the high-altitude Himalayan strain of Drosophila ananassae from Badrinath (altitude 5123 m) was temperature-dependent and at 21°C, it was entrained by cycles of 12 h light: 12 h darkness (LD 12:12) and free-ran in constant darkness, however, it was arrhythmic at 13°C or 17°C under identical experimental conditions (Khare, P. V., Barnabas, R. J., Kanojiya, M., Kulkarni, A. D., Joshi, D. S. (2002). Temperature dependent eclosion rhythmicity in the high altitude Himalayan strains of Drosophila ananassae. Chronobiol. Int. 19:1041-1052). The present studies were designed to see whether or not these strains could be entrained at 13°C, 17°C, and 21°C by two types of LD cycles in which the photoperiod at 100 lux intensity varied from 6 h to 18 h, and the light intensity of LD 14:10 cycles varied from 0.001 lux to 1000 lux. All LD cycles entrained this strain at 21°C but not at 13°C or 17°C. These results demonstrate that the entrainment of eclosion rhythm depends on the ambient temperature and not on the photoperiod or light intensity of LD cycles. Thus the temperature has taken precedence over the light in the entrainment process of eclosion rhythm of the high altitude Himalayan strain of D. ananassae. This may be the result of natural selection in response to the environmental temperature at Badrinath that resembles that of the sub-Arctic region but the photoperiod or light intensity are of the subtropical region.     

A comparison of the suitabilities of rectal,gut, and insulated axilla temperatures for measurement of the circadian rhythm of core temperature in field studies

Eight healthy males were studied for a total of 13 subject-days to assess if gut (from an ingested pill) and axilla (from a thermally insulated skin probe) temperatures would act as a substitute for rectal temperature in field studies of the circadian rhythm of core temperature. Subjects slept and went about their activities, indoors and outdoors, normally. Regular recordings (at 6min intervals) were made of temperatures from the three sites. In addition, activity was measured (by a sensor on the nondominant wrist) so that the raw temperature data could be “purified,” that is, corrected for the direct effects of sleep and activity. Inspection of the raw data indicated that there was a close parallelism between rectal and gut temperatures, but that the parallelism between rectal and insulated axilla temperatures was less reliable. This parallelism was supported by initial calculations of the correlations between rectal and gut temperatures (high and positive) and between rectal and insulated axilla (lower, though still positive) temperatures. Calculation of the limits of agreement between the parameters of the cosine curves fitted to the raw data confirmed that the rectal and gut temperatures were far closer with regard to acrophase and amplitude than were rectal and insulated axilla temperatures (-0.31±0.89 vs. +0.75±6.03 h and +0.002±0.116 vs. +0.083±0.625°C, respectively). After purification of the temperature data, the limits of agreement for the cosine parameters acrophase and amplitude still indicated that there was a closer agreement between rectal and gut temperatures than between rectal and insulated axilla temperatures (-0.30±1.12 vs. +0.58±6.69 h, and +0.007±0.116 vs. +0.104±0.620°C, respectively). Part of the explanation of this difference was the unreliable relationships between temperature changes in insulated axilla temperature and bursts of activity and going to bed. It is concluded that, whereas gut temperature is a viable alternative to rectal temperature (from the viewpoints of both user acceptability and the reliability of data obtained), insulated axilla temperature, though acceptable to subjects, is unreliable from an experimental viewpoint.     

Light and temperature cycles as zeitgebers of zebrafish (Danio rerio) circadian activity rhythms

Light and temperature cycles are the most important synchronizers of biological rhythms in nature. However, the relative importance of each, especially when they are not in phase, has been poorly studied. The aim of this study was to analyze the entrainment of daily locomotor activity to light and/or temperature cycles in zebrafish. Under two constant temperatures (20°C and 26°C) and 12:12 light-dark (LD) cycles, zebrafish were most active during the day (light) time and showed higher total activity at the warmer temperature, while diurnalism was higher at 20°C than at 26°C (87% and 77%, respectively). Under thermocycles (12:12 LD, 26:20°C thermophase:chryophase or TC), zebrafish daily activity synchronized to the light phase, both when the thermophase and light phase were in phase (LD/TC) or in antiphase (LD/CT). Under constant dim light (3 lux), nearly all zebrafish synchronized to thermocycles (τ=24 h), although activity rhythms (60% to 67% of activity occurred during the thermophase) were not as marked as those observed under the LD cycle. Under constant dim light of 3 lux and constant temperature (22.5°C), 4 of 6 groups of zebrafish previously entrained to thermocycles displayed free-running rhythms (τ=22.9 to 23.6 h). These results indicate that temperature cycles alone can also entrain zebrafish locomotor activity.     

Late Glacial and Holocene Ostracoda of the Gulf of Gdańsk,the Baltic Sea,Poland

To trace environmental changes in water hydrology and salinity in the Late Glacial to Holocene of the Gulf of Gdańsk, a south‐eastern bay of the Baltic Sea within the maritime zone of Poland, the distribution of ostracod valves was studied in 20 sediment cores collected from both the shallow‐ and deep‐water zones (depth 10.9–67.5 m). The studied sediment sequences yielded ca. 3000 valves of 21 ostracod species, of which only five are known to live today in the Gulf, which has a present maximum depth of 118 m and water salinity up to 7–8‰. The majority of the studied sediment layers that contained ostracod valves corresponded to the period of the Late Glacial to Mid‐Holocene and was dominated by non‐marine species, of which the most common were Candona neglecta (present in 17 cores), Cytherissa lacustris (15 cores) and Candona candida (14 cores). By clustering classification five major ostracod assemblage types were recognised in the studied cores. Initial assemblage types dominated mostly by inhabitants of the profundal/sub‐littoral zones of modern oligo‐mesotrophic lakes (C. lacustris and C. neglecta) in some sediment sequences were replaced in stratigraphical order by the assemblages dominated by brackish‐water species (Cyprideis torosa or Cytheromorpha fuscata). The structure and species composition of the distinguished ostracod assemblage types as well as their successional transitions indicate that the studied sediments were deposited initially in the Late Glacial in freshwater lacustrine conditions, and subsequently, during the Holocene marine transgression, covered by marine sands. The present results confirm and consolidate inferences based on previously published data on ostracods from the western part of the Gulf of Gdańsk as well as on other biotic (molluscs, diatoms) and abiotic (seismoacoustic) indices from this area (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Thermal biology of the fossorial rodent Ctenomys fulvus from the Atacama desert, northern Chile

The Andean tuco-tuco, Ctenomys fulvus (Rodentia: Ctenomyidae) inhabits one of the most arid regions of the world, the Salar de Atacama, Northeast of Antofagasta, Chile (23°17′06″S, 68°05′43″W; 2.240 m.a.s.l). We found that a stable microclimate in burrows, a low evaporative water loss (EWL), and a diet of roots (59% water content) are the main factors that permit the survival of this fossorial species in harsh desert conditions. Large circadian variation in T_a was observed above ground. Daily ΔT_a (T_a max − T_a min) = 37.9±0.2°C in summer and in winter. In contrast, circadian variation of T_a inside the burrows was only 5.8±0.5°C in the same seasons. Relative humidity (RH) was 1.9–3.1% during the day, increasing to maximum values of 27% at night and early morning. Inside the burrows RH was higher and quite stable, ranging between 53.1 and 65%, independent of the time of day and season. EWL, measured between 10 and 25°C, was low (1.26 mg/g h), and a moderate increase of 13–20% was observed at higher temperatures. The low EWL may prevent dehydration. However, because of the low heat loss capability, animals became hyperthermic (0.8–1.6°C) in dry air at T_a=30–35°C. As T_a during afternoon normally exceeded 35°C, the microclimate of burrows provided the only way to avoid the lethal effects of hyperthermia.     

Circadian modulation of starvation-induced hypothermia in sheep and goats

Prolonged food deprivation is known to cause a fall in the core body temperature of homeotherms. In various species of small birds and mammals (body mass up to 2-3 kg), it has been shown that starvation-induced hypothermia is modulated by the circadian system, in the sense that hypothermia is observed primarily during the inactive phase of the daily activity cycle (i.e., during the night for diurnal animals and during the day for nocturnal animals), whereas relatively normal temperatures are recorded during the active phase. To investigate whether this modulation occurs also in larger animals, we investigated the effects of 4d food deprivation on the body temperature rhythm of goats and sheep (body mass 30-40 kg). In goats, the body temperature rhythm was found to have a mean level of 39.0°C with a mean daily range of excursion of 0.42°C. The daily oscillation in body temperature persisted during the first day of fasting, but the rhythm was drastically damped, if not eliminated, over the next 3 d as body temperature descended from the baseline level of 39.0 to 38.2°C. In sheep, the rhythm was found to have a mean level of 39.3°C with a mean daily range of excursion of 0.34°C. The daily oscillation in body temperature persisted through the 4 d of food deprivation, even though the mean level of body temperature gradually fell. Temperature fell more during the third and fourth nights than during the third and fourth days. Thus, circadian modulation of starvation-induced hypothermia was observed in sheep but not in goats.     

Eemian and Early Weichselian vegetation and climate history in Central Europe: A case study from the Klinge section (Lusatia, eastern Germany)

The paper presents vegetation and climate reconstructions for Eemian and Early Weichselian in Central Europe based on detailed pollen data of the Klinge section. The sediments exposed in this profile were accumulated from the Saalian termination up to the Early Weichselian glaciation. A succession of forest communities, typical for the Eemian interglacial has been recorded. Pollen data indicate some oscillations during the very end of the Eemian (biozone E7). The climatic reconstructions show the heat supply rising gradually from the beginning of the interglacial to its middle part. A long-term cooling trend in January temperature was reconstructed for the second half of the interglacial. The difference between the optimum (zone E4b) and Pinus-Picea-Abies zone (E6) amounts to 4 °C, during the Pinus zone (E7) the temperature further decreased by 8 °C. The changes in July temperature were not so dramatic (about 3 °C).     

Time series analysis of magnetic susceptibility variations in deep marine sedimentary rocks: A test using the upper Danian–Lower Selandian proposed GSSP, Spain

It has been clearly demonstrated that past climate fluctuations are recorded in marine sedimentary rocks. However, for many reasons, extracting the climate signature is difficult. Initial low-field mass-specific magnetic susceptibility (MS) data can potentially provide a measure of climate variability and thus become a proxy characterizing climate cyclicity in a wide range of marine sediments. This is due to the fact that climate change (warm, wet versus cold, dry) drives cyclic weathering and erosional variations that are recorded as the detrital components of marine sediment that dominates the MS. To test the utility of MS to yield climate proxies in marine sediments showing major changes in lithology, we have sampled the well-studied Danian/Selandian boundary interval (Lower Paleocene) at Zumaia (Zumaya), Spain. This interval represents a dramatic, rapid lithologic change from Danian carbonate-dominated limestone–marl couplets to a detrital-dominated marl-shale sequence in the Selandian, indicating onset of a major regression-erosional event beginning in the lowest Selandian. Sampling included a continuous sequence from the uppermost Danian Stage (3.71 m) into the lowermost Selandian Stage (5.2 m), a suite of 175 samples collected at 5 cm intervals. Our results indicate that MS measurements reflect changes in detrital sediment at the site, first by closely tracking high-frequency limestone–marl couplets, second with a large, rapid shift toward higher MS values beginning at the Danian/Selandian boundary resulting from a major regression, and third by tracking low-frequency climate-controlled variations known to have occurred during deposition of these sediments. MS zones developed from the cyclicity observed throughout the sequence, supported by time series analysis using Fourier Transform (FT) methods applied to the MS results, exhibit Milankovitch cyclicities in the precessional (19–24 kyr), obliquity (41–54 kyr) and eccentricity bands (100 kyr). This is in excellent agreement with previous FT work on the section using measured variations in cyclic bed thicknesses. With the new MS data set and FT results, we then developed a Floating Point Time Scale (FPTS) for the sequence sampled (covering  550 kyr through the Danian/Selandian boundary interval), yielding a time-scale resolution for the uppermost Danian to  10,000 years. However, only the  100,000 year eccentricity band for the Selandian is sufficiently well developed for an FPTS estimate, and yields a time-scale resolution of  50,000 years. Our test of the utility of MS data sets in this varying depositional setting demonstrated that these data can provide a climate proxy that is not disrupted by large lithologic changes.     

Effects of a five-hour exposure of arm and leg to a slightly cool thermal environment in the afternoon on the body temperature rhythm

The purpose of this study was to determine whether the different thermal conditions of the arm and leg due to wearing different types of clothing during the afternoon could modulate the circadian rhythm of body temperature and subjective sleep quality. Six healthy female volunteers were studied twice with two types of clothing, leaving the arm and leg covered or uncovered. The environmental chamber was controlled at 24 ± 0.5°C and 50 ± 5% RH during wakefulness and 28 ± 0.5°C and 50 ± 5% RH during night sleep. One type of clothing consisted of long-sleeved shirts and full-length trousers (Type L, 989 g, 0.991 clo); the other type was of half-sleeved shirts and knee-length trousers (Type H, 750 g, 0.747 clo). One testing session lasted for 16 h from 14:00 to 06:00 h the next morning. Subjects wore Type L or Type H clothing during the afternoon exposure (14:00 - 19:00), and Type L clothing during the evening (19:00 - 22:30 h) and the night sleep (22:30 - 06:00 h). Results were as follows. (1) When wearing Type H rather than Type L clothing, skin temperatures of the arm and leg were significantly lower during the time of exposure, and increased more after the evening. (2) Rectal temperature was not significantly different between the two types of clothing except during the early part of the exposure period, but it decreased during the evening by a significantly greater amount when wearing Type H clothing. (3) Subjective sleep quality was not significantly different between the two clothing types. These results suggest that afternoon exposure of the arm and leg to a slightly cool environment does not have a strong after-effect on the body temperature and subjective sleep quality.     

Relative tolerance of cirripede larval stages to acute thermal shock: A laboratory study

(1) Meroplankters drawn into once-through cooling circuits of coastal power plants are subjected to transient thermal stress. The effect of such acute thermal shock on the development of barnacle larvae was studied in the laboratory.

(2) The response of the barnacle larvae (naupliar and cyprid stages) to elevated temperature was dependent on exposure time and their stage of development.

(3) Among the stages tested, N-6 larvae showed maximum tolerance. Exposure to 37°C did not affect larval survival, but delayed development of N-2 larva to cypris by one day.

(4) Exposure at 40°C delayed, hastened or did not affect the development time of N-2 and N-4 larvae through cypris, depending on exposure time.

(5) Ten mins exposure at 43°C proved lethal to all larval stages with mortality ranging from 20 to 86%.

(6) Development success of the surviving larvae, measured in terms of cypris yield, showed no significant difference from controls, at temperatures below 40°C.

(7) Settlement activity was significantly affected in only those cyprid larvae which were exposed to 43°C for 10 min.

(8) Results of the present study indicate that thermal stress experienced in the once-through cooling system does not have significant impact on survival and development of the barnacle larvae at temperatures of 37–40°C.     

The relative contribution of the small and large intestine to the absorption and metabolism of rutin in man

Tomato juice containing rutin (quercetin-3-rutinoside) was ingested by healthy volunteers and ileostomists. Blood and urine collected over 24 h were analysed by HPLC with photodiode array (PDA) and tandem mass spectrometric detection. Low concentrations of isorhamnetin-3-glucuronide (C_max = 4.3 ± 1.5 nmoles/l) and quercetin-3-glucuronide (C_max = 12 ± 2 nmoles/l) were detected in plasma of healthy subjects. Metabolites appeared in blood after 4 h indicating absorption from the large intestine. Nine metabolites of rutin were detected in urine but with considerable variation in total amount (40 ± 1-4981 ± 115 nmoles over 24 h). No metabolites were detected in plasma or urine of ileostomists and 86 ± 3% of the ingested rutin was recovered in ileal fluid. In subjects with an intact large intestine, but not ileostomists, rutin was catabolised with the appearance of 3,4-dihydroxyphenylacetic acid, 3-methoxy-4-hydroxyphenylacetic acid and 3-hydroxyphenylacetic acid in urine accounting for 22% of rutin intake.