Unimodal Peak Research Articles

Diversity ofStomoxysspp. (Diptera: Muscidae) and diurnal variations of activity ofStomoxys indicusandS. Calcitransin a farm, in Wang Nam Khiao District, Nakhon ratchasima Province, Thailand

A study of species diversity of Stomoxys spp. and diurnal variations of activity of the most abundant was performed during a one year period at a local dairy cattle farm in Wang Nam Khiao District, Nakhon Ratchasima Province, Thailand. Four species of stomoxyine flies were morphologically identified, including Stomoxys indicus Picard 1908, S. calcitrans (Linnaeus 1758), S. sitiens Rondani 1873 and S. uruma Shinonaga and Kanao 1966. The most common species were S. indicus (50.2%) and S. calcitrans (49.5%). S. sitiens and S. uruma were found in small proportions (< 1%). The number of flies captured was significantly different among the three seasons with the greatest number in the rainy season (mean = 66%; df = 2, P < 0.05). The variations of diurnal activity were observed during different period of times (06:00 to 18:00) during three seasons. Both sexes of S. indicus and males of S. calcitrans showed unimodal activity pattern in cool and summer seasons. But a bimodal activity pattern was recorded in rainy season. For females S. calcitrans, a unimodal peak of activity was observed in cool season and a constant variation of activity all along the day in summer and rainy seasons, with an increase from the morning to the evening. A better understanding of stomoxyine fly behavior, especially the daily flight activity, can assist in prioritization and design of appropriate vector prevention and control strategies.

Trends of Ambient Concentrations of Gaseous Air Pollutants in Almadinah Al Menawwarah, Central Area, Saudi Arabia

Nitrogen monoxide (NO), nitrogen dioxide (NO2), nitrogen oxides (NOx), sulfur dioxide (SO2), ozone (O3), carbon monoxide (CO), methane (CH4) and non-methane hydrocarbons (NMHCs) were measured in Almadinah Al Menawwarah, Saudi Arabia. From Ramadan to Hajj season (October, 2005 - January, 2006) daily average concentrations of NO, NO2, NOx, SO2, O3, CO, CH4 and NMHCs, were 0.055, 0.040, 0.095, 0.011, 0.009, 2.82, 3.83 and 1.12 ppm, respectively. The SO2/NOx and SO2/NO2 concentration ratios were 0.12 and 0.28, respectively, suggesting that the mobile emissions are the predominant sources within the study area. The diurnal variations of NO, NO2, NOx, SO2, CO, NMHCs concentrations were similar and showed two daily peaks, in the morning and late evening. These peaks concentrations are linked to traffic density, boundary layer mixing processes and chemical processes in the atmosphere. The diurnal cycles of O3 concentrations revealed a uni-modal peak in the mid-day time. The highest concentrations of the measured pollutants were found in Ramadan and Hajj seasons, due to increasing human activities. Significant positive correlation coefficients (p&lt;0.05) were found between NO, NO2, NOx, NMHCs and CO, and also between SO2 and NO, NO2, NOx, NMHCs and CH4. Significant negative correlation coefficients were found between O3 concentrations and NO2. These results indicate that an increase in O3 level is associated with a drop in the concentration of NO2, CO and NMHCs.

MULTIPLE TESTING OF LOCAL MAXIMA FOR DETECTION OF PEAKS IN 1D.

A topological multiple testing scheme for one-dimensional domains is proposed where, rather than testing every spatial or temporal location for the presence of a signal, tests are performed only at the local maxima of the smoothed observed sequence. Assuming unimodal true peaks with finite support and Gaussian stationary ergodic noise, it is shown that the algorithm with Bonferroni or Benjamini-Hochberg correction provides asymptotic strong control of the family wise error rate and false discovery rate, and is power consistent, as the search space and the signal strength get large, where the search space may grow exponentially faster than the signal strength. Simulations show that error levels are maintained for nonasymptotic conditions, and that power is maximized when the smoothing kernel is close in shape and bandwidth to the signal peaks, akin to the matched filter theorem in signal processing. The methods are illustrated in an analysis of electrical recordings of neuronal cell activity.

Basic soil properties and comprehensive evaluation in different plantations in rocky desertification sites of the karst region of Guizhou Province, China

Aims Soil quality plays an essential role in vegetation restoration in the karst soil ecosystem.Many studies have reported soil quality of different plantations and vegetation successional stages in karst regions,but few have focused on the seasonal dynamics of basic soil properties.Our objectives were to investigate annual dynamics of basic soil properties of different types of plantations and evaluate soil integrated quality index(SQI).Methods We analyzed the dynamics of soil physical and chemical properties and soil enzyme activities for four sites in Puding County,Guizhou Province,China:Robinia pseudoacacia plantation(RP),Cupressus duclouxiana plantation(CD),R.pseudoacacia-C.duclouxiana mixed plantation(RD) and a non-plantation area(CK).Soil samples were collected in alternate months from September 2009 to September 2010.Soil factors were measured using general methods,and data were analyzed using SPSS 13.0 software.Important findings Soil physical properties of all three plantations had an advantage over the non-plantation area and were slightly improved within one year.There were significant differences in soil nutrients and soil pH among the four sites(p 0.01).Soil urease activity in all sites was highest in September and lowest in January.Soil invertase activities were remarkably different among the four sites(p 0.01).Soil catalase activity exhibited a unimodal peak,and alkaline phosphatase activity had a bimodal peak.Soil polyphenoloxidase activity was lowest in January and very low in RP throughout the study.Moreover,the rank of means of five soil enzyme activities was different among the four sites.The SQI of RP,CD,RD and CK was 0.748,0.406,0.590 and 0.315,respectively.In general,all three types of plantations,but especially RP and RD,could improve soil quality after conversion of farmland to forest.

Epidemiology of IBD and Mortality and Morbidity Outcomes

Purpose: Clinicians at our hospital routinely deal with Inflammatory Bowel Disease (IBD) inpatients. However, no database existed to evaluate IBD prevalence, assess demographic variability, mortality, co-morbid associations and consult burden on other specialties. We embarked on this first of its kind study at our hospital to gather this unique and extensive data which can be further analyzed locally and nationally. Methods: We retrospectively reviewed charts of all 197 IBD patients who were admitted at our hospital from 2007-2010. Data gathering beyond 2007 was not performed because of the logistic challenge of retrieving old charts. Results: Prevalence of Ulcerative Colitis (UC) was higher than Crohn's disease (CD) in our patients which correlates with the national prevalence pattern. Both UC and CD had a female predominance being 60% and 63%, respectively. Interestingly, national figures show an unexplained increase of male predominance in UC patients. A typical “bimodal” distribution of age for IBD was noted in both UC and CD in contrast to a more nationwide emerging pattern of unimodal peak for CD followed by a steady decrease. Both UC and CD were predominantly common among African-Americans than Caucasians. However, other minority groups as Asians and Hispanics were at par with African Americans (38 % vs 38%) in UC and exceeded the number for CD (53% vs 28%). Smoking rates were comparable between UC and CD patients (13% vs 15%). All cause inpatient mortality rates for UC and CD were 4.6% and 0%, respectively. Approximately half of the IBD inpatients had a CT performed and the majority, about 90%, had pertinent findings which did not necessary always alter the diagnostic or therapeutic course of the disease. Surgical consults were called more often for CD than UC patients, 34% vs 20% of the time but not many had an actual surgical intervention. GI consult was almost always invariably called for both UC and CD patients. For both IBD subsets, only about 40% patients had an inpatient colonoscopy with 90-100% chance of positive findings. Both for UC and CD, 65% patients never had a stool CDiff ordered. However, C-Diff predominance was seen in UC compared to CD, 8.5% vs 3%, in subset of IBD patients who did actually get a stool sampling done for C-Diff. Conclusion: The Crohn's and Colitis Foundation of America attributes the lack of epidemiological databases as a particular constraint in IBD related research. Creation and maintenance of such databases would provide new opportunities to apply standard and innovative epidemiological techniques to monitor IBD prevalence, discover the etiologies of IBD, assess estimates of resource utilization and define populations at greatest or least risk.

Depositional History of the Chhattisgarh Basin, Central India: Constraints from New SHRIMP Zircon Ages: A Reply

Abstract The Indian Shield includes the Singhbhum, Bastar, and East and West Dharwar cratons. Proterozoic sedimentary basins formed on these cratons have preserved rocks with a range of degrees of metamorphism and deformation. In the Chhattisgarh Basin, within the Bastar Craton, the ca. 2200–2500-m-thick Chhattisgarh Supergroup has been preserved in nearly pristine condition. Previous work has shown that the Sukhda Tuff, located about 2200 m from the base of the section, was formed ca. 1007 Ma. New U-Pb SHRIMP age determinations show that the Singhora Tuff, located about 100 m above the base of the basin, is not older than Ma. Thus, most of the Chhattisgarh Supergroup was deposited between 1400 and 1000 Ma. Age data for detrital zircons from sandstones show that, regardless of their stratigraphic position, there is a unimodal age peak near 2500 Ma, the typical age of adjacent granitic and rhyolitic basement rocks, indicating that these constituted the principal provenance of the sediments in the Chhattisg...

Chemo-enzymatic synthesis of polyhydroxyalkanoate (PHA) incorporating 2-hydroxybutyrate by wild-type class I PHA synthase from Ralstonia eutropha

A previously established improved two-phase reaction system has been applied to analyze the substrate specificities and polymerization activities of polyhydroxyalkanoate (PHA) synthases. We first analyzed the substrate specificity of propionate coenzyme A (CoA) transferase and found that 2-hydroxybutyrate (2HB) was converted into its CoA derivative. Then, the synthesis of PHA incorporating 2HB was achieved by a wild-type class I PHA synthase from Ralstonia eutropha. The PHA synthase stereoselectively polymerized (R)-2HB, and the maximal molar ratio of 2HB in the polymer was 9 mol%. The yields and the molecular weights of the products were decreased with the increase of the (R)-2HB concentration in the reaction mixture. The weight-average molecular weight of the polymer incorporating 9 mol% 2HB was 1.00 × 10(5), and a unimodal peak with polydispersity of 3.1 was observed in the GPC chart. Thermal properties of the polymer incorporating 9 mol% 2HB were analyzed by DSC and TG-DTA. T (g), T (m), and T (d) (10%) were observed at -1.1°C, 158.8°C, and 252.7°C, respectively. In general, major components of PHAs are 3-hydroxyalkanoates, and only engineered class II PHA synthases have been reported as enzymes having the ability to polymerize HA with the hydroxyl group at C2 position. Thus, this is the first report to demonstrate that wild-type class I PHA synthase was able to polymerize 2HB.

Circadian activity rhythms in relation to season, sex and interspecific interactions in two Mediterranean voles

Although environmental conditions and biotic interactions are widely recognized as key sources of variation in circadian activity rhythms of a broad array of vertebrates, information on their actual significance outside experimental settings remains scarce. We investigated changes in circadian activity rhythms of free-ranging Cabrera voles, Microtus cabrerae , and water voles, Arvicola sapidus , in highly seasonal Mediterranean environments, and analysed how such changes were further affected by intersexual and interspecific interactions. Cabrera voles were largely diurnal, with a unimodal peak around midday during the wet season, whereas during the dry season activity was reduced during the hot midday period and increased strongly at dawn and dusk. Water voles also had a marked bimodal crepuscular pattern during the dry season, but this was much attenuated during the wet season, when they were comparatively more diurnal. Activity patterns varied little between the sexes, although with a tendency for higher overall activity by male Cabrera voles (dry season only) and water voles, possibly because of intersexual interactions involving seasonal shifts from monogamy to facultative polygyny in Cabrera voles, and year-round polygyny in water vole. Within each season, Cabrera voles appeared to change their activity patterns in the presence of water voles, reducing overall activity and shifting activity peaks towards diurnal (dry season) or crepuscular (wet season) time periods less used by water voles. Overall, this study provides evidence for the strong role of seasonal changes in environmental conditions and interspecific interactions in driving variation in the activity patterns of Mediterranean voles under natural conditions.

Emergence of a mid-season period of low floral resources in a montane meadow ecosystem associated with climate change

1. Shifts in the spatial and temporal patterns of flowering could affect the resources available to pollinators, and such shifts might become more common as climate change progresses. 2. As mid-summer temperatures have warmed, we found that a montane meadow ecosystem in the southern Rocky Mountains of the United States exhibits a trend toward a bimodal distribution of flower abundance, characterized by a mid-season reduction in total flower number, instead of a broad, unimodal flowering peak lasting most of the summer season. 3. We examined the shapes of community-level flowering curves in this system and found that the typical unimodal peak results from a pattern of complementary peaks in flowering among three distinct meadow types (dry, mesic and wet) within the larger ecosystem. However, high mid-summer temperatures were associated with divergent shifts in the flowering curves of these individual meadow types. Specifically, warmer summers appeared to cause increasing bimodality in mesic habitats, and a longer interval between early and late flowering peaks in wet and dry habitats. 4. Together, these habitat-specific shifts produced a longer mid-season valley in floral abundance across the larger ecosystem in warmer years. Because of these warming-induced changes in flowering patterns, and the significant increase in summer temperatures in our study area, there has been a trend toward non-normality of flowering curves over the period 1974–2009. This trend reflects increasing bimodality in total community-wide flowering. 5. The resulting longer periods of low flowering abundance in the middle of the summer season could negatively affect pollinators that are active throughout the season, and shifts in flowering peaks within habitats might create mismatches between floral resources and demand by pollinators with limited foraging ranges. 6. Synthesis. Early-season climate conditions are getting warmer and drier in the high altitudes of the southern Rocky Mountains. We present evidence that this climate change is disrupting flowering phenology within and among different moisture habitats in a sub-alpine meadow ecosystem, causing a mid-season decline in floral resources that might negatively affect mutualists, especially pollinators. Our findings suggest that climate change can have complex effects on phenology at small spatial scales, depending on patch-level habitat differences.

Depositional History of the Chhattisgarh Basin, Central India: Constraints from New SHRIMP Zircon Ages

Abstract The Indian Shield includes the Singhbhum, Bastar, and East and West Dharwar cratons. Proterozoic sedimentary basins formed on these cratons have preserved rocks with a range of degrees of metamorphism and deformation. In the Chhattisgarh Basin, within the Bastar Craton, the ca. 2200–2500-m-thick Chhattisgarh Supergroup has been preserved in nearly pristine condition. Previous work has shown that the Sukhda Tuff, located about 2200 m from the base of the section, was formed ca. 1007 Ma. New U-Pb SHRIMP age determinations show that the Singhora Tuff, located about 100 m above the base of the basin, is not older than Ma. Thus, most of the Chhattisgarh Supergroup was deposited between 1400 and 1000 Ma. Age data for detrital zircons from sandstones show that, regardless of their stratigraphic position, there is a unimodal age peak near 2500 Ma, the typical age of adjacent granitic and rhyolitic basement rocks, indicating that these constituted the principal provenance of the sediments in the Chhattisg...

Detrital zircon UPb ages, Hf isotopes and tectonic implications for Palaeozoic sedimentary rocks from the Xing‐Meng orogenic belt, middle‐east part of inner Mongolia, China

AbstractThe Xing‐Meng Orogenic Belt is the eastern extension of the Central Asian Orogenic Belt that marks the boundary between the North China Block and the Siberian Block. Studies of zircon UPb ages and Hf isotopic compositions show that four clastic sedimentary rock samples from different parts of the regional stratigraphic sequence were deposited at different ages, none earlier than Mid‐ or Early Silurian. Two sedimentary rocks were deposited during or after the Early Permian. Almost all zircons are of igneous origin. In Silurian and Devonian sediments, zircons show several modal age peaks, and in Permian sediments, zircons show a unimodal age peak. Based on the zircon age distribution of sedimentary rocks versus known ages from exposed rocks of the potential source regions, most of the zircons were derived from the Xing‐Meng Orogen itself. A few came from the South Mongolian microcontinent or the Siberia Block, but none came from the North China Block. The zircons of a biotite‐plagioclase paragneiss in Xilinhot have similar provenance to the sediments and were deposited during or after the Middle Devonian. Similarities between zircon age spectra and events in underlying rocks of sedimentary origin show that the sediments lie at their deposition site north of the Solonker suture zone because north‐dipping subduction and elevation blocked deposition of material from farther afield. Hf isotope compositions show the crustal accretion stages of the provenance areas during the Meso‐ to Neoarchaean, Palaeoproterozoic and Early and Late Palaeozoic. A two‐component mixing calculation based on Hf isotopes shows the large scale of the crustal accretion event of the region. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Combination of starvation interval and food volume determines the phase of liver circadian rhythm in Per2::Luc knock-in mice under two meals per day feeding

Although the circadian liver clock is entrained by the feeding cycle, factors such as food volume and starvation interval are poorly understood. Per2::Luc knock-in mice were given two meals per day with different food volume sizes and/or with different intervals of starvation between two mealtimes with the total food volume per day fixed at 3.6 g (80 food pellets, ∼75% of free feeding) per mouse. The bioluminescence rhythm in the liver produced a unimodal peak but not bimodal peak under the regimen of two meals per day over 14-15 days. Peak Per2 expression occurred concurrently with the mealtime of the larger food volume, when the first and second meal were given as different food volume ratios under a 12 h feeding interval. When an equal volume of food was given under different starvation interval (8 h:16 h), the peak of the Per2 rhythm was close to peak by mealtime after long starvation (16 h). When food volumes for each mealtime were changed under 8 h:16 h, the peak rhythm was influenced by combined factors of food volume and starvation interval. Food intake after the 16-h starvation caused a significant increase in liver Per2, Dec1, and Bmal1 gene expression compared with food intake after the 8-h starvation with 8 h:16 h feeding intervals. In conclusion, the present results clearly demonstrate that food-induced entrainment of the liver clock is dependent on both food volume and the starvation interval between two meals. Therefore, normal feeding habits may help to maintain normal clock function in the liver organ.

Prevalence and epidemiology of pandemic H1N1 strains in hospitals of Eastern India

A novel Influenza A (pH1N1) virus which emerged in April, 2009, spread rapidly across the continents to become pandemic by June, 2009. In Eastern India, testing for influenza was initiated in June, 2009 and continued through July, 2010 to determine prevalence and epidemiological character of circulating pandemic H1N1 strain. Real time PCR was done on nasal and throat swab samples of patients with influenza like symptoms of those who sought medical care in local government hospitals. Of 2971 patients tested, 382 (12.86%) were positive for influenza A and 103 (3.47%) for influenza B. Of 382 influenza A positives, 284 (74.35%) and 98 (25.65%) were subtyped as pandemic H1N1 (pH1N1) and seasonal H1N1 and H3N2, respectively. The novel pH1N1 virus followed typical influenza seasonality in Eastern India and revealed a unimodal peak in July and August, correlating with the rainy season. Most of the positive cases presented with mild ILI symptoms with minimal serious complications. Though four deaths were attributed to pH1N1 infection in 2010, all four had underlying serious medical complications. Infection rate was highest in age group of >55 years followed by 5 - <18 years of age group. Key words: Pandemic, H1N1, influenza.

Demographic Differences Among Patients with Inflammatory Bowel Disease in the U.S Military Health System: 2010 ACG/Centocor IBD Abstract Award

Purpose: Determine the demographic differences among patients seen for inflammatory bowel diseases (IBD) in the U.S Military Health System. Methods: There are a number of demographic and putative factors associated with IBD. The military population offers a relatively consistent and unique but ethnically and geographically diverse population. We analyzed a military wide clinical database of an electronic medical record (EMR) with more than 45 million patient encounters in 2008, using ICD-9 codes to search then compare demographic differences among our military (active or retired) and civilian (non-military) beneficiaries with IBD. Results: A total of 8,194 patients were seen at direct access military hospitals during 2008 for ulcerative colitis or Crohn's disease. 41.4 % were white, 8.2% were black and 50.4% were non-white, non-black. Men comprised the majority of service members (active or retired) while women comprised the majority of our civilian cohort. There were slightly more civilian beneficiaries (53.3%) with IBD, than active or retired service member beneficiaries. The age distribution between these two groups was similar(mean age in years: 39 +/-16 civ, 41 +/-15 mil). The percentage of patients with IBD peaked in the 3rd decade (24.7%) of life and declined in each subsequent decade. More people were seen with a diagnosis of UC than Crohn's (51.9% vs. 48.1%). However, there was a gender difference with IBD phenotype; with male predominance for UC (54.7%) and female predominance for Crohn's (53.7%). Conclusion: Many putative risk factors have been implicated in the development of inflammatory bowel diseases. Our findings are consistent with recent studies suggesting a male predominance in ulcerative colitis, and a female predominance in Crohn's disease. Although not a true incidence assessment, the uni-modal peak in age during the 3rd to 4th decades is supportive of recent studies. More data is needed to determine if particular service experiences in the military affect these diseases.

Seasonality in the altitude–diversity pattern of Alpine moths

Altitudinal gradients are frequently used to study environmental effects on species diversity. Recent quantitative studies on Lepidoptera focussed on tropical mountain systems and often reported unimodal diversity peaks at “mid-elevations”;, a pattern also often found in other taxa. Here we used methodologically comparable, nocturnal Macrolepidoptera samples from the Swiss Alps to analyze environmental correlates of diversity. Using seasonal data (monthly samples from April to November at altitudes between 600 and 2400 m a.s.l.) allowed to decouple altitude and some climate variables for analyses. We found that the altitude–diversity pattern changes with season. In spring and autumn, diversity decreased with increasing altitude, while we found a unimodal peak of diversity at mid-elevations during summer. This excluded all hypothetical causes of diversity variation that do not allow for seasonality. Temperature was an important correlate of diversity, whereas precipitation was not. These results were separately corroborated for the two most common families (Noctuidae and Geometridae). However, diversity patterns of the two families were not particularly close, and unexplained variance of climatic explanations was substantial in all cases. The patterns of faunal overlap did not explain the unimodal diversity pattern, and we claim that we lack a generally valid explanation for this common phenomenon.

It’s All in the Timing: Birth Seasonality and Infant Survival in Eulemur rubriventer

Highly seasonal breeding has been considered one of the keys to understanding Malagasy primate socioecology. Strict seasonal breeding may be particularly critical for Malagasy primates because they live in such energetically challenging seasonal environments. Lemurs also live in highly unpredictable environments, and there is growing evidence that reproductive timing may be mediated by additional factors, suggesting that more relaxed breeding seasonality is adaptive in some cases. I tested the adaptive breadth of the birth peak in Eulemur rubriventer, which breed in several different months. I describe reproduction in the species by determining the timing and extent of the birth season (period in which all births occur) and birth peak (period in which the majority of births occur); test whether relaxed reproductive seasonality might increase reproductive success by comparing infant mortality within and outside the birth peak; and model the extent to which fruit availability has an influence on the timing of reproduction. I collected birth data on 5 groups in 2003–2005, which I combined with demographic data that D. Overdorff collected from 5 focal groups and additional censused groups between 1988 and 1996. Thirty births occurred in 8 different months. Births were significantly seasonal, with a unimodal birth peak in late August/September/October, and a mean birth date of October 11. Twenty-three births (76.7%) occurred within 54 d (14.79%) of the year. No births occurred May–July, indicating that conceptions did not occur from late December through late February, and cycling (estimated using gestation length) did not occur until ca. 101 d after the austral summer solstice (December 21). Of 22 infants followed regularly, 18 were born in the birth peak, of which 2 died (11%). All 4 infants born out of season died. Based on fruit availability, I calculated a Theoretical Overlap index (T), which indicated a 3-mo window with optimal food conditions for reproduction. This window corresponded to the timing and breadth of the birth peak in Eulemur rubriventer. These results indicate that a breeding season >3 mo within a given year is not adaptive in the species, likely due in large part to the availability of fruit during key reproductive stages, particularly before breeding.

Intraseasonal Variability of Satellite-Derived Rainfall and Vegetation over Southern Africa

Abstract Satellite-derived rainfall and vegetation [normalized difference vegetation index (NDVI)] data for the period 1981–2000 are used to reveal spatial and temporal interrelationships via principal component analysis. The unimodal seasonal cycle peaks in austral summer over the Zambezi Valley and interior plateau. Spectral analysis indicates major cycles of intraseasonal rainfall events at ∼20 and 40 days in response to atmospheric wave forcing that is partially phase locked to the annual cycle. The spatial loadings exhibit a “center of action” along the eastern edge of the Kalahari (±23°E), extending from the western Zambezi toward central South Africa, spanning 20° of latitude. The loading pattern is consistent with tropical–temperate troughs and associated northwest (NW) cloud bands. Twenty-day rainfall oscillations occur over the Agulhas Current and Angola, hence NW cloud bands are a slower terrestrial harmonic of the faster modes at either end. NDVI also exhibits intraseasonal cycles operating near 40 days with spatial loadings collocated with the slow rainfall mode at a 10–20-day lag. It is postulated that an earlier rainfall event and subsequent “greening” results in a moisture flux that promotes the next rainfall event. This is reflected in a composite analysis of low-level velocity potential. The vegetation draws airflow toward itself in a self-sustaining way.

The reproductive biology of a Central American cichlid Neetroplus nematopus in Lake Xiloá, Nicaragua

Abstract This study was conducted to provide a five-year database on the breeding seasonality and breeding biology of a Central American cichlid fish Neetroplus nematopus, a biparental substratum-spawning cichlid that cares for its eggs, wrigglers, and fry for up to six weeks. A total of 503 breeding pairs were monitored for breeding success. Breeding pairs of N. nematopus are sexually dimorphic in size, with females averaging 39% of male body mass. Fry emerged from 85% of nesting cavities. After three weeks, only 30% of the broods were present in the nesting cavity; these broods had a 30% survival rate, giving a 9% overall survival rate. Nineteen percent of the successful parents with three-week-old broods adopted foreign fry. A consistent unimodal breeding peak in December was observed for five years. This breeding peak differed dramatically from the bimodal breeding season 20 years found in the 1970s. The effects of extensive grenade fishing practices during the 1980s might have played a substantial role in the observed change. Grenade fishing stopped in 1991, and the number of N. nematopus pairs increased by 136% from 1990 to 1995. With increased density of breeding fish, the breeding season for this species also expanded. The balance between divergent selection due to competition for breeding sites and stabilizing selection due to predation pressure on offspring is likely to mold the breeding season for N. nematopus and other cichlids of Lake Xiloá. We suggest that brood adoption and synchrony of breeding is a strategy to reduce predation on the parent's own young.

Difference of delayed post-tonsillectomy bleeding between children and adults

Objective To analyze the characteristics of post-tonsillectomy bleeding and its management comparing with adults. Methods A retrospective chart review of 1489 patients who underwent tonsillectomy in our institution (June 2003–June 2006). Results Post-tonsillectomy bleeding rate was 3.1%, 2.5% and 10.8% in younger children (age ≤ 11 years), older children (12 ≤ age ≤ 15 years) and adults (age > 15 years), respectively. Although adults showed an unimodal peak time for onset of post-tonsillectomy bleeding, children showed a bimodal peak time. In the younger child group, all of the 28 bleeders had spontaneous hemostasis. However, in the older child group, there was no spontaneous hemostasis. Bleeding was controlled under local anesthesia in 3 patients and 2 patients required general anesthesia for bleeding control. In the adult group, spontaneous cessation of bleeding occurred in 25 patients (60.9%) and hemostasis under local or general anesthesia was performed in 16 (39.1%) patients. Conclusions Post-tonsillectomy bleeding occurred more frequently in adults than in children. Spontaneous hemostasis was more prevalent in children than in adults. Post-tonsillectomy bleeding in the younger child group was controlled with close observation alone.

The nonequilibrium phase transition and the symmetry revival induced by time delay in an asymmetric bistable system with correlated noises

The nonequilibrium phase transition and the symmetry revival induced by time delay in a bistable system are investigated. The stationary probability distribution function (SPDF) of the bistable system with time delay and correlated noises are calculated by an analytical method and stochastic simulation respectively. The analytical and simulative results indicate that: (1) There is a certain value of λ(λ denotes the strength of correlations between the multiplicative and additive noises) to make the SPDF symmetric under some time delay; however, above or below the given value, the symmetry will be broken; (2) With the monotonic change of λ, the unimodal peak structure of SPDF becomes bimodal at the beginning, then it becomes unimodal again; this means that there is a reentrance phenomenon in the process; (3) There is a critical value of delay time, which makes the lower peak of SPDF equal to the higher one under the critical condition. This means that the symmetry revival phenomenon emerges.