Morning‐to‐Evening Differences in Oxygen Uptake Kinetics in Short‐Duration Cycling Exercise

This study analyzed diurnal variations in oxygen (O₂) uptake kinetics and efficiency during a moderate cycle ergometer exercise. Fourteen physically active diurnally active male subjects (age 23±5 yrs) not specifically trained at cycling first completed a test to determine their ventilatory threshold (T_vent) and maximal oxygen consumption (VO_2max); one week later, they completed four bouts of testing in the morning and evening in a random order, each separated by at least 24 h. For each period of the day (07:00–08:30 h and 19:00–20:30 h), subjects performed two bouts. Each bout was composed of a 5 min cycling exercise at 45 W, followed after 5 min rest by a 10 min cycling exercise at 80% of the power output associated with T_vent. Gas exchanges were analyzed breath‐by‐breath and fitted using a mono‐exponential function. During moderate exercise, the time constant and amplitude of VO₂ kinetics were significantly higher in the morning compared to the evening. The net efficiency increased from the morning to evening (17.3±4 vs. 20.5±2%; p<0.05), and the variability of cycling cadence was greater during the morning than evening (+34%; p<0.05). These findings suggest that VO₂ responses are affected by the time of day and could be related to variability in muscle activity pattern.     

Origin of pre‐islamic architecture in West‐Africa

’Cultural theory’, launched by social anthropologist Mary Douglas, has been highly influential in the inter‐disciplinary field concerned with the study of risk perception and risk communication. The theory derives from the grid‐group analyses that Douglas developed in the 1970s. Cultural theory aims to explain universal ‘cultural bias’ by way of a general typology of group formation and a concomitant cosmology or world view. This article critically examines cultural theory and the study of hazards as culturally construed phenomena.     

Internal colonialism in Austria‐Hungary

Affirmative discrimination re‐visited

Glazer, N. AFFIRMATIVE DISCRIMINATION: ETHNIC INEQUALITY AND PUBLIC POLICY, Harvard University Press, 1975 (2nd ed. 1987), 248 pp. £7.25. Combs, M. W. and Gruhl. J. (eds) AFFIRMATIVE ACTION: THEORY, ANALYSIS AND PROSPECTS, McFarland, USA, 1986, 185 pp. n.p.

Günther Glebe and John O'Loughlin (eds), FOREIGN MINORITIES IN CONTINENTAL EUROPEAN CITIES, Stuttgart, Steiner‐Verlag‐Wiesbaden‐GmbH, 1987, 296 pp., n.p.     

Long‐term wildlife road‐kill counts in New Zealand

Abstract

We compare the number of medium‐sized animals (between rat and dog‐size) killed on repeated counts along the same 1660 km of North Island highways in 1984, 1994 and 2005 with other counts going back to 1949. Elevenmammal and 14 bird species were recorded, but Australian possums (Trichosurus vulpecula), hedgehogs (Erinaceus europaeus) and rabbits (Oryctolagus cuniculus) predominated, and pukekos (Porphyrio porphyrio), mynas (Acridotheres tristis), and Australian magpies (Gymnorhina tibicen) were the most common birds. Counts of possums, hedgehogs and rabbits ranged between 0.7 and 89 corpses/100 km, and changed dramatically over six decades. The possum count rose 80% between 1984 and 1994, but declined 60% by 2005. A possible irruption of hedgehogs is reported in 1988–89, followed by an 82% decline in their numbers between 1994 and 2005. Although rabbit hemorrhagic disease was introduced to New Zealand in 1997, rabbit road‐kill increased 59% between 1994 and 2005. The relationship between road‐kill and traffic volume indicates that roads carrying more than 3000 vehicles per day act as barriers to larger mammals, while vehicles on less busy roads are more dangerous for crossing animals. We suggest that regular counts taken at annual intervals over the same roads is a useful method for gathering information about the changing distribution and relative abundance of certain animals on a provincial or national scale and over long periods of time. Regular counts at seasonal, monthly or weekly intervals are also a rich source of information.     

Twenty‐Four‐Hour and Annual Variation in Onset of Epistaxis in Osler Disease

Osler disease is an autosomal dominant disorder of the fibrovascular tissue characterized by arteriovenous malformations with multi‐systemic haemorrhages. Recurrent epistaxis is the predominant symptom in more than 90% of patients. Recent studies showed circadian and seasonal patterns in the onset of nosebleeds, similar to acute cardiovascular events, such as myocardial infarction and stroke. The aim of this study was to determine whether such patterns would also apply to the onset of epistaxis in patients with Osler disease. In all, 110 patients with Osler disease who were under treatment for recurrent epistaxis at the University Hospital of Mannheim were requested to complete a questionnaire addressing the intensity and frequency of epistaxis according to the classification of Bergler et al., as well as circadian and circannual rhythmicity in the occurrence of epistaxis according to visual analogue scales (VAS). More than half of the patients claimed to experience daily to weekly episodes of recurrent epistaxis. The occurrence of epistaxis showed a biphasic 24 h pattern, with a primary peak in the morning (05∶00–8∶00 h) and smaller secondary peaks in the evening (17∶00–20∶00 h and 21∶00–00∶00 h). No significant seasonal variation was found in the onset of epistaxis. However, a slight tendency, with a peak in winter months, was observed. Similar to other chronobiological studies on nosebleeds, this study showed that the 24 h pattern and seasonal tendency in the onset of epistaxis even applied to patients with Osler disease. Further investigations are necessary to determine the pathological mechanism underlying this phenomenon.     

Messinian‐Zanclean vegetation and climate in North‐Central Italy

A palynological study was carried out on four Italian Miocene‐Pliocene sections ranging in age from uppermost Tortonian to Zanclean located on the Adriatic side of the North‐Central Apennines. The study documents the Mediterranean isolation, the salinity crisis (s.s), the “lago‐mare”; event and the re‐establishment of open‐marine conditions in the Mediterranean at the beginning of the Pliocene. From a climatic point of view, a transition from subtropical/warm‐temperate conditions during the Messinian to warm‐temperate/temperate conditions during the Zanclean is recorded. The presence of a lower thermic level, with respect to the Messinian, the re‐establishment of open‐marine conditions and the uplift of the Apennines were major factors controlling paleoenvironmental variations during the Zanclean. The latter is also characterized by cyclic temperature oscillations. Correlations with coeval sections in the Mediterranean area confirm the existence of latitudinal climatic gradients within the studied area.     

The calcium‐dependent protein kinase ZmCDPK7 functions in heat‐stress tolerance in maize

Global warming poses a serious threat to crops. Calcium‐dependent protein kinases (CDPKs)/CPKs play vital roles in plant stress responses, but their exact roles in plant thermotolerance remains elusive. Here, we explored the roles of heat‐induced ZmCDPK7 in thermotolerance in maize. ZmCDPK7‐overexpressing maize plants displayed higher thermotolerance, photosynthetic rates, and antioxidant enzyme activity but lower H₂O₂ and malondialdehyde (MDA) contents than wild‐type plants under heat stress. ZmCDPK7‐knockdown plants displayed the opposite patterns. ZmCDPK7 is attached to the plasma membrane but can translocate to the cytosol under heat stress. ZmCDPK7 interacts with the small heat shock protein sHSP17.4, phosphorylates sHSP17.4 at Ser‐44 and the respiratory burst oxidase homolog RBOHB at Ser‐99, and upregulates their expression. Site‐directed mutagenesis of sHSP17.4 to generate a Ser‐44‐Ala substitution reduced ZmCDPK7's enhancement of catalase activity but enhanced ZmCDPK7's suppression of MDA accumulation in heat‐stressed maize protoplasts. sHSP17.4, ZmCDPK7, and RBOHB were less strongly upregulated in response to heat stress in the abscisic acid‐deficient mutant vp5 versus the wild type. Pretreatment with an RBOH inhibitor suppressed sHSP17.4 and ZmCDPK7 expression. Therefore, abscisic acid‐induced ZmCDPK7 functions both upstream and downstream of RBOH and participates in thermotolerance in maize by mediating the phosphorylation of sHSP17.4, which might be essential for its chaperone function.     

Intra‐ethnic and inter‐ethnic marriage and divorce in Hawaii

Abstract

A comparison of intra‐ and inter‐ethnic divorce rates in Hawaii showed that inter‐ethnic marriages resulted in a higher proportion of divorces than did intra‐ethnic marriages when the marriage data used had to do with all marriages occurring in Hawaii. However, a sizeable portion of marriages in Hawaii are of nonresidents who, if they divorce, probably divorce elsewhere. Nonresident marriages are chiefly intra‐ethnic marriages of Caucasians. When examining the proportions of divorces to resident marriages, within‐group marriages are more at risk than inter‐ethnic marriages. As in prior research, persons who marry members of other racial/ethnic groups tend to marry persons from groups with income levels similar to their own. As in previous reports, some cross‐ethnic combinations appeared more at risk for divorce than did others. Group income appeared to be a predictor of risk. When considering only resident marriages as related to divorces, those marriages in which the bride was from a higher income group than the groom were at a significantly greater risk for divorce than marriage in which the bride came from an income group lower than that of the groom.     

Circadian Variations in the Activities of 6‐Phosphogluconate Dehydrogenase and Glucose‐6‐Phosphate Dehydrogenase in the Liver of Conrol and Streptozotocin‐Induced Diabetic Rats

The aim of this study was to examine: the 24 h variation of 6‐phosphogluconate dehydrogenase and glucose‐6‐phosphate dehydrogenase activities, key enzymes for the maintenance of intracellular NADPH concentration, in rat liver in control and streptozotocin‐induced diabetic animals. Adult male rats were fed ad libitum and synchronized on a 12:12 h light‐dark cycle (lights on 08:00 h). One group of animals was treated with streptozotocin (STZ, 55 mg/kg, intraperitoneal) to induce experimental diabetes. Eight weeks after STZ injection, the animals were sacrificed at six different times of day—1, 5, 9, 13, 17 and 21 Hours After Lights On (HALO)—and livers were obtained. Enzyme activities were determined spectrophotometrically in triplicate in liver homogenates and expressed as units per mg protein. 6‐phosphogluconate dehydrogenase activity was measured by substituting 6‐phosphogluconate as substrate. Glucose‐6‐phosphate dehydrogenase activity was determined by monitoring NADPH production. Treatment, circadian time, and interaction between treatment and circadian time factors were tested by either one or two way analysis of variance (ANOVA). Two‐way ANOVA revealed that 6‐phosphogluconate dehydrogenase activity significantly depended on both the treatment and time of sacrifice. 6‐phosphogluconate dehydrogenase activity was higher in control than diabetic animals; whereas, glucose‐6‐phosphate dehydrogenase activity did not vary over the 24 h in animals made diabetic by STZ treatment. Circadian variation in the activity of 6‐phosphogluconate dehydrogenase was also detected in both the control and STZ treatment groups (one‐way ANOVA). Time‐dependent variation in glucose‐6‐phosphate dehydrogenase activity during the 24 h was detected in control but not in diabetic rats. No significant interaction was detected between STZ‐treatment and time of sacrifice for both hepatic enzyme activities. These results suggest that the activities of NADPH‐generating enzymes exhibit 24 h variation, which is not influenced by diabetes.     

Spring‐autumn variations in hemispheric asymmetry

Abstract

48 right‐handed subjects performed verbal and spatial hemifield tachistoscopic tasks, half of them during spring and the other half during autumn. Results showed increased visual field advantage both in performance speed and accuracy in the right visual field during spring and in the left visual field during autumn. This suggests a seasonal‐hemispheric shift favouring the left hemisphere during spring and the right hemisphere during autumn, and provides a clue to understanding seasonal variations in mood and affective states as related to variations in cognitive style.     

The uptake and metabolism of fructose‐1,6‐diphosphate in rat cardiomyocytes

Fructose1,6diphosphate (FDP) is a glycolytic intermediate which has been theorized to increase the metabolic activity of ischemic tissues. Here we examine the effects of externally applied FDP on cardiomyocyte uptake and metabolism. Adult rat cardiomyocytes were isolated and exposed to varying concentrations (0, 5, 25 and 50 mM) of FDP for either 1, 16 or 24 h of hypoxia (95% N₂/5% CO₂), each time period followed by a 1 h reoxygenation (95% air/5% CO₂). The uptake of FDP by rat cardiomyocytes was more concentrationdependent than timedependent. Furthermore, the uptake of FDP by the cardiomyocytes was similar in the hypoxia and normoxia treated cells. Alamar Blue, a redox indicator that is sensitive to metabolic activity, was used to monitor the effects of the FDP on cardiomyocyte metabolism. In the 1 h hypoxia or normoxia group, the 5, 10 and 25 mM FDP showed a significant increase in metabolism compared to the control cells. When the length of hypoxia was extended to 16 h, all doses of FDP were greater than control. And at the 24 h hypoxia or normoxia time period, only the 10, 25 and 50 mM FDP groups were greater than control. The results indicate a non-linear trend between the external concentration of FDP and the changes noted in metabolism. The findings from this study indicate that a narrow concentration range between 5–10 mM augments cardiomyocyte metabolism, but higher or lower doses may have little additional affect.     

Age‐related changes in miR‐143‐3p:Igfbp5 interactions affect muscle regeneration

A common characteristic of aging is defective regeneration of skeletal muscle. The molecular pathways underlying age‐related decline in muscle regenerative potential remain elusive. microRNAs are novel gene regulators controlling development and homeostasis and the regeneration of most tissues, including skeletal muscle. Here, we use satellite cells and primary myoblasts from mice and humans and an in vitro regeneration model, to show that disrupted expression of microRNA‐143‐3p and its target gene, Igfbp5, plays an important role in muscle regeneration in vitro. We identified miR‐143 as a regulator of the insulin growth factor‐binding protein 5 (Igfbp5) in primary myoblasts and show that the expression of miR‐143 and its target gene is disrupted in satellite cells from old mice. Moreover, we show that downregulation of miR‐143 during aging may act as a compensatory mechanism aiming at improving myogenesis efficiency; however, concomitant upregulation of miR‐143 target gene, Igfbp5, is associated with increased cell senescence, thus affecting myogenesis. Our data demonstrate that dysregulation of miR‐143‐3p:Igfbp5 interactions in satellite cells with age may be responsible for age‐related changes in satellite cell function.     

Seasonal Variation in Onset of Myocardial Infarction—A 7‐year single‐center study in Italy

Like many other serious acute cardiovascular and cerebrovascular events, acute myocardial infarction (AMI) shows seasonal variation, being most frequent in the winter. We sought to investigate whether age, gender, and hypertension influence this pattern. We studied 4014 (2259 male and 1755 female) consecutive patients with AMI presenting to St. Anna Hospital of Ferrara, Italy between January 1998 and December 2004. Some 1131 (28.2%) of the AMI occurred in persons <65 yrs of age, and 2883 (71.8%) in those ≥65 yrs of age. AMI was over‐represented in males (82% in the <65 yr group vs. 56.6% in the ≥65 yr group (χ²=13.99; p<0.001). Hypertension had been previously documented in 964 (24%) of the cases. There were 691 (17.2%) fatal case outcomes; fatal outcomes were significantly higher among the 3054 normotensive (n=614 or 20.1%) than the 964 hypertensive cases (n=77 or 8%; χ²=74.94, p<0.001). AMIs were most frequent in the winter (n=1076 or 26.8% of all the events) and least in the summer (n=924 or 23.0% of all the events; χ²=12.36, p=0.007). The greatest number of AMIs occurred in December (n=379 or 9.44%), and the lowest number in September (n=293 or 7.3%; χ²=11.1, p=0.001). Inferential chronobiological (Cosinor) analysis identified a significant annual pattern in AMI in those ≥65 yrs of age, with a peak between December and February—January for the total sample (p<0.005), January for the sample of males (p=0.014), February for fatal infarctions (p=0.017), and December for non‐fatal infarctions (p=0.006). No such temporal variations were detected in any of these categories in those <65 yrs of age. The annual pattern in AMI was also verified by Cosinor analysis in the following hypertensive subgroups: hypertensive males (n=552: January, p=0.014), non‐fatal infarctions in hypertensive patients (n=887: January, p=0.018), and elderly normotensives (n=1556: November, p=0.007).     

Seasonal variations in lectin‐induced lymphocyte transformation in beagle dogs

Abstract

The lymphocyte stimulation test (LST) is an in vitro corollary of in vivo cell‐mediated immunity. We have analyzed LST results from 32 dogs covering a 16‐month time span. Two mitogens (plant lectins) were used in the LST, phytohemagglutinin (PHA) and concanavalin A (Con A) with comparable results. All dogs exhibited a seasonal variation in LST results using both mitogens. The dogs were either controls or were in one of five groups that received whole‐body gamma ray irradiation from a ⁶⁰CO source. There was little effect of irradiation except on the mean levels of oscillation. Few differences were noted among groups. The estimated mean times of peak activity in the LST ranged from July 19‐August 2 for PHA and from July 18‐August 15 for Con A. The times of peak of individual dogs for both mitogens were predominantly in the calendar quarter June 21 ‐September 20, and were, therefore, not randomly distributed throughout the year. The implications of these findings are discussed.     

Acetyl‐ed question in mitochondrial biology?

Lysine acetylation on numerous mitochondrial proteins, targeted by the sirtuin deacylase SIRT3, has been proposed to play a major role in regulating diverse mitochondrial functions, particularly in the liver. A new study by Weinert, Choudhary, and colleagues, in this issue of The EMBO Journal, finds that the absolute levels of hepatic mitochondrial protein acetylation in wild‐type mice are extremely low and may be insufficient to exert regulatory effects.     

Territory re‐establishment in Cyprinodon variegatus lacepede

Cyprinodon variegatus males were allowed to establish territories in small aquaria. The ability of a male to maintain a territory was examined under conditions that varied group composition and sequentially varied space availability. Three cohorts of males were identified: non‐territorial individuals, rarely territorial individuals, and frequently territorial individuals. The results indicate that group social structure is not affected by changes in available space. Although no single male was always territorial in trials that varied group composition, a small number of males were frequently territorial. Often these successful males were temporarily displaced, but they typically regained a territory in subsequent trials.     

Good‐for‐nothing haya names: Powers of recollection in northwest Tanzania

This article explores names and naming practices in Haya communities of Northwest Tanzania. Certain Haya names evoke past experiences and circumstances that surround the birth of a child, as well as the social reputation of the child's parents, I argue that this act of recollection embedded in such names can best be understood as an effort to displace past reputations, and overcome the disparaging views of one's consociates. From this perspective, Haya names can be understood as modes of remembering designed to both recall and undermine past memories; as well as forms of social agency through which people actively attempt to engage in and transform their social conditions.