scholarly journals Altitudinal variation of the sex ratio and segregation by gender in the dioecious plant Mercurialis perennis L. (Euphorbiaceae) in Serbia

2007 ◽  
Vol 59 (3) ◽  
pp. 193-198 ◽  
Author(s):  
Dragana Cvetkovic ◽  
V. Jovanovic
Keyword(s):  
Sex Ratio ◽  
Wide Distribution ◽  
Spatial Segregation ◽  
Sexually Dimorphic ◽  
Altitudinal Variation ◽  
Altitudinal Range ◽  
Spatio Temporal ◽  
The Difference ◽  
Spatial Segregation Of Sexes ◽  
Male Frequency

The sex ratio is one of the most intriguing problems for evolutionary biologists. Spatio-temporal variation of male frequency in sexually dimorphic plant species, spatial segregation, and differential investment of the two sex functions have attracted much research interest. In this study, we examined altitudinal variation of the sex ratio and segregation by gender in Mercurialis perennis (dog?s mercury), a dioecious anemophilous species with wide distribution. The eight studied populations from Serbia represented an altitudinal range of 196 to 1480 m. Sex ratio was significantly biased in seven of the eight populations, with males outnumbering females 3.91:1 in the lowest-altitude population. Our results support the notion of spatial segregation of sexes along on altitudinal gradient: the frequency of males decreased with altitude, from 79.6% to 41.0%. The sex ratio was not significantly correlated with population density. We also examined intersexual differences of plant height in two populations from the extremes of the studied altitudinal range. Males were the larger sex in both populations, though the difference was not significant in the high-altitude population. .

Male-biased sex ratio in Argulus canadensis Wilson, 1916 (Crustacea: Branchiura) ectoparasitic on sticklebacks

1989 ◽  
Vol 67 (8) ◽  
pp. 2078-2080 ◽  
Author(s):  
Robert Poulin ◽  
Gerard J. FitzGerald
Keyword(s):  
Salt Marsh ◽  
Sex Ratio ◽  
Laboratory Experiments ◽  
Fish Predation ◽  
Reproductive Behaviour ◽  
Egg Deposition ◽  
Alternative Hypotheses ◽  
Biased Sex Ratio ◽  
The Difference ◽  
Fish Hosts

Females of the ectoparasitic crustacean Argulus canadensis must leave their fish hosts at least temporarily to deposit their eggs on the substrate. To test the hypothesis that this difference in reproductive behaviour between the two sexes could result in male-biased sex ratios on their stickleback hosts, we sampled sticklebacks in tide pools of a Quebec salt marsh from early July to early September 1986. During this period, fish harboured significantly more male than female A. canadensis. Laboratory experiments were done to test two alternative hypotheses offered to explain this biased sex ratio. The first hypothesis was that male A. canadensis were more successful than females in attacking their stickleback hosts; however, we found no differences in attack success on their hosts between the two parasite sexes. The second hypothesis was that sticklebacks ate more female than male A. canadensis. Although males were less vulnerable to fish predation than females, the difference was not significant. We conclude that sexual differences in reproductive behaviour, i.e., egg deposition behaviour of females, can account for the male-biased sex ratio of A. canadensis on sticklebacks.

scholarly journals Sexual dimorphism in a top predator ( Notophthalmus viridescens ) drives aquatic prey community assembly

2018 ◽  
Vol 285 (1890) ◽  
pp. 20181717 ◽  
Author(s):  
Denon Start ◽  
Stephen De Lisle
Keyword(s):  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Intraspecific Variation ◽  
Structure And Function ◽  
Sexually Dimorphic ◽  
Ecological Communities ◽  
Top Predator ◽  
Aquatic Mesocosms ◽  
And Function ◽  
The Impact

Intraspecific variation can have important consequences for the structure and function of ecological communities, and serves to link community ecology to evolutionary processes. Differences between the sexes are an overwhelmingly common form of intraspecific variation, but its community-level consequences have never been experimentally investigated. Here, we manipulate the sex ratio of a sexually dimorphic predacious newt in aquatic mesocosms, then track their impact on prey communities. Female and male newts preferentially forage in the benthic and pelagic zones, respectively, causing corresponding reductions in prey abundances in those habitats. Sex ratio differences also explained a large proportion (33%) of differences in the composition of entire pond communities. Ultimately, we demonstrate the impact of known patterns of sexual dimorphism in a predator on its prey, uncovering overlooked links between evolutionary adaptation and the structure of contemporary communities. Given the extreme prevalence of sexual dimorphism, we argue that the independent evolution of the sexes will often have important consequences for ecological communities.

scholarly journals Ad hoc properties and locations in Maltese

2015 ◽  
Vol 1 ◽  
pp. 64-85 ◽  
Author(s):  
Gréte Dalmi
Keyword(s):  
Ad Hoc ◽  
Semantic Theory ◽  
Alternative States ◽  
Verbal Predicate ◽  
Spatio Temporal ◽  
The Difference ◽  
Copular Sentences ◽  
Event Variable ◽  
Temporal Variable ◽  
Account Variation

This paper aims to show that the four-way BE-system of Maltese can best be accommodated in a theory of non-verbal predication that builds on alternative states, without making any reference to the Davidsonian spatio-temporal event variable. The existing theories of non-verbal predicates put the burden of explaining the difference between the ad hoc vs. habitual interpretations either solely on the non-verbal predicate, by postulating an event variable in their lexical layer (see Kratzer 1995; Adger and Ramchand 2003; Magri 2009; Roy 2013), or solely on the copular or non-copular primary predicate, which contains an aspectual operator or an incorporated abstract preposition, responsible for such interpretive differences (Schmitt 2005, Schmitt and Miller 2007, Gallego and Uriagereka 2009, 2011, Marín 2010, Camacho 2012). The present proposal combines Maienborn’s (2003, 2005a,b, 2011) discourse-semantic theory of copular sentences with Richardson’s (2001, 2007) analysis of non-verbal adjunct predicates in Russian, based on alternative states. Under this combined account, variation between the ad hoc vs. habitual interpretations of non-verbal predicates is derived from the presence or absence of a modal OPalt operator that can bind the temporal variable of non-verbal predicates in accessible worlds, in the sense of Kratzer (1991). In the absence of this operator, the temporal variable is bound by the T0 head in the standard way. The proposal extends to non-verbal predicates in copular sentences as well as to argument and adjunct non-verbal predicates in non-copular sentences.

scholarly journals Geometry and the Mechanism of Landslide Occurrence in a Limestone Area – Case Examples of Landslides in Vietnam and from Europe, China, and Japan –

2021 ◽  
Vol 16 (4) ◽  
pp. 646-657
Author(s):  
Bui Duc Tung ◽  
Ngoc Ha Do ◽  
Nguyen Kim Thanh ◽  
Le Hong Luong ◽  
Osamu Watanabe ◽  
...  
Keyword(s):  
Southern China ◽  
Accretionary Prism ◽  
Wide Distribution ◽  
Case Examples ◽  
Landslide Occurrence ◽  
Sedimentary Characteristics ◽  
Tethys Sea ◽  
Wide Range ◽  
The Difference ◽  
Mechanism Of Landslide

Landslide damage has been reported in many limestone areas in Europe, where the population lives close to limestone areas, and in Guilin in southern China and Ha Long in Vietnam, which are known for their unique limestone landscapes. There are few studies on the mechanism and type of landslide motion in and around such limestone areas. The lack of basic data is a problem for risk assessment and countermeasures in limestone areas. In this study, we summarized the causes and mechanisms of landslide occurrence, including geology and groundwater, focusing on six landslides that occurred in limestone areas in northern Vietnam, and classified them into six types of landslide movement. In the case of Japan, the occurrence of landslides in limestone areas is rare despite the wide distribution of limestone, and it is difficult to classify the type of movement. Differences in the landslide mechanisms are caused by the difference between limestones generated in the pelagic environment of Japan and limestones developed along the Tethys Sea coast, which are mixed with pelitic rocks as shallow-water sediments in Europe, China, and Vietnam. It is necessary to elucidate the relationship between landslides and the formation environment and sedimentary characteristics of limestone as an accretionary prism based on comparisons of a wide range of cases in future studies.

scholarly journals Short-term stock assessment of Loligo gahi at the Falkland Islands: sequential use of stochastic biomass projection and stock depletion models

2006 ◽  
Vol 64 (1) ◽  
pp. 3-17 ◽  
Author(s):  
Rubén Roa-Ureta ◽  
Alexander I. Arkhipkin
Keyword(s):  
Sex Ratio ◽  
Stock Assessment ◽  
Scaling Factor ◽  
Falkland Islands ◽  
Short Term ◽  
Projection Model ◽  
Biomass Estimate ◽  
Projected Length ◽  
Spatio Temporal ◽  
Stock Depletion

Abstract Roa-Ureta, R. and Arkhipkin, A. I. 2007. Short-term stock assessment of Loligo gahi at the Falkland Islands: sequential use of stochastic biomass projection and stock depletion models – ICES Journal of Marine Science, 64, 3–17. Two short-term stock assessment models are combined to examine the pre-season, in-season, and post-season dynamics of the Loligo gahi fishery off the Falkland Islands over four consecutive fishing seasons. A stochastic biomass projection model (SBPM) projects a pre-season survey-based biomass estimate from the date of the survey to the start of the season. A stock depletion model (SDM) assesses in-season biomass from commercial daily catch-and-effort data. The SBPM projects the SDM biomass estimate at the end of the season to a post-season date of spawning. Combining the SBPM and the SDM helps to clarify the spatio-temporal functioning of the stock and to assess the comparability of survey- and fishery-based estimates of biomass. For the first 2005 season, projected length frequencies indicate two pulses of recruitment onto the fishing grounds. Survey-based projections of biomass were lower than equivalent fishery-based estimates. Over two surveys, the sex ratio was balanced, suggesting full recruitment of both sexes onto the fishing grounds, and the ratio of survey-projected to fishing-estimated biomass was constant. This constant is interpreted as a scaling factor between survey biomass and absolute biomass.

Trends of Diabetes Mortality in Iran at National and Sub-national levels from 1990 to 2015 and its association with socioeconomic factors

2020 ◽  
Author(s):  
Niloofar Peykari ◽  
Sahar Saeedi Moghaddam ◽  
Nazila Rezaei ◽  
Anita Mansouri ◽  
Shohreh Naderimagham ◽  
...  
Keyword(s):  
Mortality Rate ◽  
Socioeconomic Factors ◽  
National Level ◽  
Gaussian Process Regression ◽  
Mortality Trends ◽  
Registration System ◽  
Diabetes Mortality ◽  
Spatio Temporal ◽  
The Difference ◽  
National Trends

Abstract Background Following global commitments to prevent and control non-communicable diseases, we sought to estimate national and sub-national trends in diabetes mortality in Iran and to assess its association with socioeconomic factors.Methods To assess the correlation between diabetes mortality and socioeconomic factors we used data obtained from the Death Registration System (DRS), the spatio-temporal model and Gaussian Process Regression (GPR) levels and the diabetes mortality trends, which were estimated by sex, age and year at national and sub-national levels from 1990 to 2015.Results Between the years 1990 and 2015, the age-standardized diabetes mortality rate (per 100,000) increased from 3.40 (95% UI: 2.33 to 4.99) to 7.72 (95% UI: 5.51 to 10.78) in males and from 4.66 (95% UI: 3.23 to 6.76) to 10.38 (95% UI: 7.54 to 14.23) in females. In 1990, the difference between the highest age-standardized diabetes mortality rate among males was 3.88 times greater than the lowest (5.97 vs. 1.54) and in 2015 this difference was 3.96 times greater (14.65 vs. 3.70). This provincial difference was higher among females and was 5.13 times greater in 1990 (8.41 vs. 1.64) and 5.04 times greater in 2015 (19.87 vs. 3.94). The rate of diabetes mortality rose with urbanization, yet declined with an increase in wealth and years of schooling as the main socio-economic factors.Conclusion The rising trend of diabetes mortality rate at national level and the sub-national disparities associated with socioeconomic status in Iran warrant the implementation of specific interventions recommended by the ‘25 by 25’ goal.

Implications of Spatio-Temporal Variation in Forage Production and Utilization for Animal Productivity in Extensive Grazing Systems.

1998 ◽  
Vol 20 (1) ◽  
pp. 3 ◽  
Author(s):  
DA Roshier ◽  
HI Nicol
Keyword(s):  
Temporal Variation ◽  
Management Practice ◽  
Animal Production ◽  
Forage Production ◽  
Forage Availability ◽  
Typical Experiment ◽  
Grazing Systems ◽  
Spatio Temporal ◽  
The Difference ◽  
Plant Animal Interactions

In this paper we examine patterns of utilisation at the level of individual plants and forage availability at the paddock scale on five commercial sheep grazing properties that all experienced drought during the course of the study. Specifically, patterns of forage availability and pasture utilisation in large paddocks are examined against the assumptions of established models of animal productivity and grazing management practice. Forage resources in the rangelands can have dynamics independent of stock density and are not distributed evenly in time or space. Therefore, the extrapolation of known plant-animal interactions across scales is questionable and it is yet to be demonstrated how measures of animal productivity on small trial paddocks relate to production outcomes in large paddocks. A model is proposed for understanding animal production outcomes that incorporates variation in both pasture biomass and stock density. The scales, both spatial and temporal, at which pastoralists and scientists integrate ecological and animal productivity information usually differ. The understanding that each holds of the processes that limit animal productivity and the relationships between different elements of the production system is a product of the perspective from which they view the system. It is concluded that the difference between the 'scale of exploitation' and the scale at which heterogeneity is sufficient for survival of livestock is probably crucial to determining animal production outcomes in grazing systems subject to a high degree of temporal variation in forage availability. In these systems it seems reasonable to suggest that grazing experiments that vary the 'spatial scale of exploitation' while maintaining stock density constant may give as many insights into the limitations on animal productivity as the more typical experiment that only varies stock density. Key words: grazing models, animal productivity, heterogeneity, scale, utilisation, forage availability, stocking rates.

Demography and home range of the eastern barred bandicoot (Perameles gunnii) in south-eastern Tasmania

2000 ◽  
Vol 27 (1) ◽  
pp. 103 ◽  
Author(s):  
Stephen A. Mallick ◽  
Michael M. Driessen ◽  
Gregory J. Hocking
Keyword(s):  
Body Weight ◽  
Sex Ratio ◽  
Home Range ◽  
Home Ranges ◽  
Sexually Dimorphic ◽  
South Eastern ◽  
Small Width ◽  
Live Trapping ◽  
Dry Conditions ◽  
Two Populations

We used live-trapping to study the demography and movement of two populations of the eastern barred bandicoot, Perameles gunnii, in south-eastern Tasmania from 1992 to 1996. Densities were 0.35–2.35 animals ha–1. Sex ratios were male-dominated on Grid I and female-dominated on Grid II. The average body weight for sexual maturity was 700g for males and 680g for females, while the lowest recorded weight for a breeding female was 570g. Perameles gunnii was sexually dimorphic, with males having a greater body weight and pes length than females. Recruitment was 25.4–32.1%, residence 46.7–100.0%, and emigration 16.5–25.5% of the population. Three juveniles were recruited to the Grid I population, 55 to Grid II, with a steady decline in the number of juveniles recruited to Grid II over the four years of the study. Breeding occurred year-round. Mean litter size was 2.53, with 78.2% of all litters having either 2 or 3 young. Mean longevity for male and female P. gunnii was 7.91 and 10.54 months, respectively. Home ranges of males (4.29 ha) were significantly larger than those of females (2.34 ha), although this may represent a significant underestimate due to the small width of our grids (200m) relative to the home-range area. There was only moderate overlap (19.3%) between home ranges of males and females. The overlap between male/male home ranges (4.4%) was significantly less than the overlap between female/female home ranges (15.8%). Perameles gunnii carried both ticks and fleas, with flea infestation being significantly higher on Grid I than on Grid II. Both populations underwent a significant decline over the study period, apparently the result of the unusually dry conditions over the first 3 years of the study. A deterioration in conditions was associated with a steady loss of resident adults, declining recruitment of juveniles and an increase in the male/female sex ratio. The sex ratio of P. gunnii populations may provide a convenient index of habitat quality, with poor or deteriorating conditions apparently associated with a high or increasing numbers of males to females.

Pulsatile growth hormone secretion in the ovine fetus and neonatal lamb

1986 ◽  
Vol 109 (3) ◽  
pp. 307-312 ◽  
Author(s):  
N. S. Bassett ◽  
P. D. Gluckman
Keyword(s):  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Pulse Height ◽  
Late Gestation ◽  
Sexually Dimorphic ◽  
Related Factors ◽  
Active Labour ◽  
Ovine Fetus ◽  
The Difference ◽  
Plasma Gh

ABSTRACT The ontogenesis of the pulsatility of GH in the ovine fetus was determined by obtaining blood samples at 20-min intervals for 3-h periods from fetuses (n = 33) at various stages of development (76–147 days gestation), and in neonatal life (n = 19). A significant increase (P <0·01) in the GH mean, nadir and maximum, and pulse height was observed between the ages of 100 and 130–139 days of gestation. An analysis of the difference in the mean, maximum and nadir concentrations between 100 and 139 days of gestation revealed that males had higher GH levels than females (P <0·05). There was a significant fall in plasma GH concentrations from 140 days of gestation to term, but before the onset of active labour. There was a more rapid fall in the circulating levels of fetal GH directly following birth. Immediately before birth fetal GH levels were still relatively high, but within 60 min of birth they had fallen by more than 80%. It is suggested that these changes in the pulsatile pattern of GH release are a consequence of both maturational changes in the hypothalamic-pituitary unit and the effects of pregnancy-related factors on GH release. The sexually dimorphic nature of GH release in the adult is also observed in the sheep fetus during late gestation. J. Endocr. (1986) 109, 307–312

scholarly journals Spatio-Temporal Validation of AIRS CO2 Observations Using GAW, HIPPO and TCCON

2020 ◽  
Vol 12 (21) ◽  
pp. 3583
Author(s):  
Hui Yang ◽  
Gefei Feng ◽  
Ru Xiang ◽  
Yunjing Xu ◽  
Yong Qin ◽  
...  
Keyword(s):  
Co2 Concentration ◽  
Satellite Observations ◽  
Total Carbon ◽  
Near Surface ◽  
Temporal Validation ◽  
Satellite Sensors ◽  
Spatio Temporal ◽  
The Difference ◽  
Carbon Dioxide Co2

Carbon dioxide (CO2) is a significant atmospheric greenhouse gas and its concentrations can be observed by in situ surface stations, aircraft flights and satellite sensors. This paper investigated the ability of the CO2 satellite observations to monitor, analyze and predict the horizontal and vertical distribution of atmospheric CO2 concentration at global scales. CO2 observations retrieved by an Atmospheric Infrared Sounder (AIRS) were inter-compared with the Global Atmosphere Watch Program (GAW) and HIAPER Pole-to-Pole Observations (HIPPOs), with reference to the measurements obtained using high-resolution ground-based Fourier Transform Spectrometers (FTS) in the Total Carbon Column Observing Network (TCCON) from near-surface level to the mid-to-high troposphere. After vertically integrating the AIRS-retrieved values with the column averaging kernels of TCCON measurements, the AIRS observations are spatio-temporally compared with HIPPO-integrated profiles in the mid-to-high troposphere. Five selected GAW stations are used for comparisons with TCCON sites near the surface of the Earth. The results of AIRS, TCCON (5–6 km), GAW and TCCON (1 km) CO2 measurements from 2007 to 2013 are compared, analyzed and discussed at their respective altitudes. The outcomes indicate that the difference of about 3.0 ppmv between AIRS and GAW or other highly accurate in situ surface measurements is mainly due to the different vertical altitudes, rather than the errors in the AIRS. The study reported here also explores the potential of AIRS satellite observations for analyzing the spatial distribution and seasonal variation of CO2 concentration at global scales.

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