Occurrence Of Dominance Research Articles

Aphasia due to right hemisphere infarction in a patient with situs inversus after carotid artery stenting: a case report

BackgroundSitus inversus (SI) is a rare congenital anomaly in which systemic organs and vessels are positioned in a mirror image of their normal positions. An interesting issue regarding individuals with such a condition is whether they also have reversed brain asymmetries. Most of studies on this issue indicate that, similarly to many people with normal visceral alignment, patients with SI have a left hemispheric dominance for language functions.Case presentationWe report a rare occurrence of anomalous cerebral dominance for language in a patient with complete situs inversus. The right-handed patient developed aphasia after carotid stenting, and brain magnetic resonance imaging showed cerebral infarction in the right parietal lobe.ConclusionAnomalous cerebral dominance for language and visceral situs inversus in our patient both may result from a single, genetically coded atypicality of developmental gradient.

Exposure pathways matter: Aquatic phototrophic communities respond differently to agricultural run‐off exposed via sediment or water

Abstract Small shallow ponds are widespread but understudied water bodies in agricultural landscapes. Agricultural run‐off (ARO) transports pesticides and nutrients into adjacent aquatic ecosystems where they occur dissolved in the water column or are bound to sediments. Consequently, aquatic communities are affected by ARO via different exposure pathways. We hypothesize that sediment‐bound ARO mainly affects submerged rooted macrophytes, while phytoplankton and periphyton are more prone to ARO in water. These primary producers compete for resources resulting in a regime shift between alternative stable states of macrophyte or phytoplankton dominance. We hypothesize that warming increases nutrient release from sediments and thereby facilitates the occurrence of phytoplankton dominance. Using a full‐factorial microcosm design, we exposed aquatic primary producers to either sediment or water application of a mixture of common pesticides (terbuthylazine, pirimicarb, tebuconazole and copper) and nitrate at two concentrations and two temperatures (22°C and 26°C) for 4 weeks. Initial and final concentrations of pesticides and nitrate, final biomass of macrophytes, periphyton and phytoplankton, pesticide accumulation in macrophytes and changes in carbon, nitrogen and phosphorus content and selected exoenzyme activities in the sediment were measured. We found lower final macrophyte biomass for both ARO treatments compared to controls, indicating a prevalence of negative effects by herbicides and competition for light with other phototrophs. In contrast, phytoplankton and periphyton biomass increased, but only when exposed to ARO via the water column, indicating a prevalence of positive effects by nutrient supply. Microbial carbon and nutrient cycling in sediments was not affected by ARO. Higher temperature mitigated ARO‐related effects on macrophytes under sediment exposure. Synthesis and application. ARO poses a strong risk of submerged macrophyte loss and establishment of turbid conditions with phytoplankton dominance in aquatic ecosystems. In conclusion, exposure pathways as well as indirect and interacting effects of multiple stressors need to be considered when designing appropriate mitigation measures. Under climate change, we suggest to prioritize local measures as buffer strips a reduced use of pesticides and fertilizers, and sediment removal as appropriate measures to protect these vulnerable but widespread aquatic systems, which are highly relevant for biodiversity in agricultural landscapes.

Paleoenvironmental significance of Benthic Foraminifera and Ostracoda from the late Quaternary of the Ceará Basin, Brazilian Equatorial Margin

Benthic foraminifera, ostracods and pteropods are reliable paleoenvironmental indicators in Quaternary deposits. However, in the Ceará Basin, on the Brazilian Equatorial Margin, these microfossils are poorly studied. This paper investigates environmental changes during the Pleistocene–Holocene transition in the Icaraí subbasin based on micropaleontological analysis of the core ANP 1011. Seventy-four taxa of benthic foraminifera, represented predominantly by Globocassidulina, Uvigerina, Pyrgo and Melonis, have been identified. The ostracod assemblages are composed mainly by the families Macrocyprididae, Cytheruridae, Trachyleberididae, Pontocyprididae and Krithidae, of which the genus Krithe was the most abundant. The composition of the ostracod assemblages identified in this study area differs somewhat from other regions of the Brazilian Margin. The assemblages of foraminifera and ostracod characterize a typical bathyal paleoenvironment. The occurrence of pteropods and dominance of epifaunal foraminifera taxa, mainly Pyrgo sp. and Miliolinella sp. in the lower portion of the core (Pleistocene), indicates higher phytodetritus input and oxygen concentration. A conspicuous environmental change was observed in the upper portion of the core, which corresponds to the Holocene, where the increase of infaunal foraminifera (e.g., Uvigerina, Globocassidulina and Melonis) suggests reduction in the organic matter input and, probably, increased bacterial density and depletion in dissolved oxygen in the sediment.

Evaluating drivers of female dominance in the spotted hyena

IntroductionDominance relationships in which females dominate males are rare among mammals. Mechanistic hypotheses explaining the occurrence of female dominance suggest that females dominate males because (1) they are intrinsically more aggressive or less submissive than males, and/or (2) they have access to more social support than males.MethodsHere, we examine the determinants of female dominance across ontogenetic development in spotted hyenas (Crocuta crocuta) using 30 years of detailed behavioral observations from the Mara Hyena Project to evaluate these two hypotheses.ResultsAmong adult hyenas, we find that females spontaneously aggress at higher rates than males, whereas males spontaneously submit at higher rates than females. Once an aggressive interaction has been initiated, adult females are more likely than immigrant males to elicit submission from members of the opposite sex, and both adult natal and immigrant males are more likely than adult females to offer submission in response to an aggressive act. We also find that adult male aggressors are more likely to receive social support than are adult female aggressors, and that both adult natal and immigrant males are 2–3 times more likely to receive support when attacking a female than when attacking another male. Across all age classes, females are more likely than males to be targets of aggressive acts that occur with support. Further, receiving social support does slightly help immigrant males elicit submission from adult females compared to immigrant males acting alone, and it also helps females elicit submission from other females. However, adult females can dominate immigrant males with or without support far more often than immigrant males can dominate females, even when the immigrants are supported against females.DiscussionOverall, we find evidence for both mechanisms hypothesized to mediate female dominance in this species: (1) male and female hyenas clearly differ in their aggressive and submissive tendencies, and (2) realized social support plays an important role in shaping dominance relationships within a clan. Nevertheless, our results suggest that social support alone cannot explain sex-biased dominance in spotted hyenas. Although realized social support can certainly influence fight outcomes among females, adult females can easily dominate immigrant males without any support at all.

Frequency of Occurrence and Level of Dominance of Alien and Native Species in Synanthropic Plant Communities of Southern Russia

Frequency of Occurrence and Level of Dominance of Alien and Native Species in Synanthropic Plant Communities of Southern Russia

The Island of Female Power? Intersexual Dominance Relationships in the Lemurs of Madagascar

The extant primates of Madagascar (Lemuriformes) represent the endpoints of an adaptive radiation following a single colonization event more than 50 million years ago. They have since evolved a diversity of life history traits, ecological adaptations and social systems that rivals that of all other living primates combined. Their social systems are characterized by a unique combination of traits, including the ability of adult females to dominate adult males. In fact, there is no other group of mammals in which female dominance is so widespread. Yet, recent research has indicated that there is more interspecific variation in lemur intersexual relationships than previously acknowledged. Here, we therefore review and summarize the relevant literature, quantifying the extent of sex-bias in intersexual dominance relations documented in observational and experimental studies in captivity and the wild. Female dominance is often, but not always, implemented by spontaneous male submission in the absence of female aggression and linked to female sexual maturation. We connect the available evidence to the hypotheses that have been proposed to explain the evolution of female dominance among lemurs. The occurrence of female dominance in all lemur families and the interspecific variation in its extent indicate that it has evolved soon after lemurs colonized Madagascar – presumably in response to particular ecological challenges – and that it has since been reduced in magnitude independently in some taxa. Our study contributes important comparative information on sex roles from an independent primate radiation and provides general insights into the conditions, opportunities and obstacles in the evolution of female-biased power.

New Insights into the Male Morphotypes of the Amphidromous Shrimp Macrobrachium olfersii (Weigmann, 1836) (Caridea: Palaemonidae) and a Discussion on Social Dominance Hierarchies.

Male morphotypes in a population may lead to the development of social dominance hierarchies in crustacean species. Currently, Macrobrachium is the decapod crustacean genus with the largest record of species that present the development of hierarchies. Macrobrachium olfersii has morphological characteristics that indicate the presence of male social dominance within its populations. Thus, the present study tested the hypothesis of the occurrence of male morphotypes in M. olfersii through morphometric and morphological analysis of the chelipeds. Sampling was carried out from March 2018 to October 2021 in seven points along the Jequitinhonha River, Northeast Brazil. A total of 264 males were collected with carapace length (CL) ranging from 4.01 to 23.70 mm. Morphological sexual maturity size was estimated at 8.95 mm CL. The morphometric and morphological analysis confirmed the presence of three adult male morphotypes: M1, M2, and M3. The characterization of the different morphotypes was mainly due to the variation in size, shape, and morphology of the largest cheliped of the second pair of pereopods. Most morphometric relationships differed significantly (p < 0.01) among the three morphotypes, mainly between M3 against M1 and M2. The variation in the propodus shape was also evident. This trait and the angulation of the spines differed significantly between morphotypes (p < 0.01), with the propodus of morphotype M3 being more robust and carrying a greater number of spines than the others. The occurrence of social dominance and the exaggerated development of a cheliped (weapon) can be advantageous for dominant individuals when they need to compete for resources. This morphological trait can provide these individuals with advantages during fights and guarantee access to the best resources, whether they are shelter, food, or sexual partners. Our results add new information to the biology of M. olfersii, as well as the genus Macrobrachium, and the occurrence of social dominance in species of this group. In addition, by describing these morphotypes in detail, using a set of complementary morphological and morphometric techniques, it is possible to access the differential morphology along the M. olfersii males, as well as confirm a life history trait found in several Macrobrachium species.

Aquatic insects, a tool for monitoring the health of riverine ecosystem, a case study of Killiyar, Thiruvananthapuram, Kerala, India

Aquatic insects are used as model organisms for assessing the health status of lenthic or lotic ecosystems. Biomonitoring using entomological indicators is one of the widely accepted tools to analyze the impacts of sewages in aquatic environment. The present study was aimed to assess the health status of a semi urban river system, Killiyar using entomological indicators. Season wise sampling of aquatic insects was done at four selected segments according to the rapid bioassessment protocol recommended by Environmental Protection Agency. The present study could identify 29 families of aquatic insects for screening the levels of pollution in Killiyar. Family Biotic Index (FBI) showed that there was a remarkable variation in water quality along the river. Hilsenhoff’s family biotic index obtained for river origin was in the range 4.40 - 5.02 indicating excellent water quality. High value of family biotic index, least occurrence of intolerant groups and dominance of tolerant taxa in the midstream and downstream segments showed that increased contamination of water by various sources. Immediate attention is needed to cease the degradation of this precious ecosystem. Keywords: Aquatic insects, Biomonitoring, Family Biotic Index, Killiyar, Water pollution

Automatic detection of microsleep episodes with feature-based machine learning.

Microsleep episodes (MSEs) are brief episodes of sleep, mostly defined to be shorter than 15 s. In the electroencephalogram (EEG), MSEs are mainly characterized by a slowing in frequency. The identification of early signs of sleepiness and sleep (e.g. MSEs) is of considerable clinical and practical relevance. Under laboratory conditions, the maintenance of wakefulness test (MWT) is often used for assessing vigilance. We analyzed MWT recordings of 76 patients referred to the Sleep-Wake-Epilepsy-Center. MSEs were scored by experts defined by the occurrence of theta dominance on ≥1 occipital derivation lasting 1-15 s, whereas the eyes were at least 80% closed. We calculated spectrograms using an autoregressive model of order 16 of 1 s epochs moved in 200 ms steps in order to visualize oscillatory activity and derived seven features per derivation: power in delta, theta, alpha and beta bands, ratio theta/(alpha + beta), quantified eye movements, and median frequency. Three algorithms were used for MSE classification: support vector machine (SVM), random forest (RF), and an artificial neural network (long short-term memory [LSTM] network). Data of 53 patients were used for the training of the classifiers, and 23 for testing. MSEs were identified with a high performance (sensitivity, specificity, precision, accuracy, and Cohen's kappa coefficient). Training revealed that delta power and the ratio theta/(alpha + beta) were most relevant features for the RF classifier and eye movements for the LSTM network. The automatic detection of MSEs was successful for our EEG-based definition of MSEs, with good performance of all algorithms applied.

Inheritance of harvest index in common bean

Abstract The aim of this study was to verify if the harvest index (HI) of common bean is higher in modern lines, to verify if its estimate varies with the cycle of the plant and environmental conditions, and to obtain information concerning its genetic control (through diallel crossing). For this purpose, six lines were crossed in a diallel. Evaluations were carried out in three crop seasons/generations - F2, F3, and F4. A receptacle was used to collect leaves, pods, and other plant parts that fell before harvest. Diallel analysis was performed using Griffing's method II. It found that the HI was higher in modern lines and was not affected by the cycle; the estimated HI heterosis was negative, indicating the occurrence of dominance in order to reduce trait expression.

Occurrence of ovarian follicular dominance during stimulation for IVM impacts usable blastocyst yield.

ObjectiveTo evaluate the influence of ovarian follicular dominance on the outcome of oocyte in-vitro maturation.MethodsThis retrospective cohort study included 21 patients with polycystic ovaries or polycystic ovary syndrome (Rotterdam criteria, 2004) subjected to 24 in-vitro maturation (IVM) cycles between October 2015 and January 2017. Patients undergoing IVM received minimal gonadotropin stimulation starting on day 2 or 3 of the cycle; ovum pick-up typically occurred on days 6 to 8. No hCG-trigger shot was given. Following 30h of IVM, mature oocytes were inseminated by ICSI and the resulting embryos cultured up to the blastocyst stage.ResultsOvarian follicular dominance was observed in nine of the 24 IVM cycles. Oocyte IVM yielded an overall maturation rate of 69.3±23.8%, and no difference was observed when the groups with or without a dominant follicle were assessed independently. The rates of fertilization and usable blastocysts per fertilized oocyte, mature oocyte (Metaphase II) or cumulus-oocyte-complex were nearly three times higher (28.7±22.5%) in the group without ovarian follicular dominance. No differences were found in the clinical pregnancy rates attained by the individuals with or without a dominant follicle after 21 vitrified-warmed blastocyst transfer cycles.ConclusionOccurrence of ovarian follicular dominance during hormonal stimulation for in-vitro maturation negatively impacted embryological outcomes. Strategies devised to limit the appearance of ovarian follicular dominance must be further explored.

Decadal variations in diatoms and dinoflagellates on the inner shelf of the East China Sea, China

Diatoms and dinoflagellates are two major groups of phytoplankton that flourish in the oceans, particularly in coastal zone and upwelling systems, and their contrasting production have been reported in several world seas. However, this information is not available in the coastal East China Sea (ECS). Thus, to investigate and compare the decadal trends in diatoms and dinoflagellates, a sediment core, 47 cm long, was collected from the coastal zone of the ECS. Sediment chlorophyll-a (Chl-a), phytoplankton-group specific pigment signatures of diatoms and dinoflagellates, and diatom valve concentrations were determined. The sediment core covered the period from 1961 to 2011 AD. The chlorophyll-a contents ranged from 2.32 to 73 µg/g dry sediment (dw) and averaged 9.81 µg/g dw. Diatom absolute abundance ranged from 29152 to 177501 valve/gram (v/g) dw and averaged 72137 v/g dw. Diatom valve and diatom specific pigment marker concentrations were not significantly correlated. Peridinin increased after the 1980s in line with intensified use of fertilizer and related increases in nutrient inputs into the marine environment. The increased occurrence of dinoflagellate dominance after the 1980s can be mostly explained by the increase in nutrients. However, the contribution of dinoflagellates to total phytoplankton production (Chl-a) decreased during the final decade of this study, probably because of the overwhelming increase in diatom production that corresponded with the construction of the Three Gorges Dam (TGD) and related light availability. Similarly, the mean ratio of fucoxanthin/peridinin for the period from 1982 to 2001 was 6% less than for 1961 to 1982, while the ratio for 2001 to 2011 was 45.3% greater than for 1982 to 2001. The decadal variation in the fucoxanthin/peridinin ratio implies that dinoflagellate production had been gradually increasing until 2001. We suggest that the observed changes can be explained by anthropogenic impacts, such as nutrient loading and dam construction.

Factors Affecting the Occurrence of Distal Radioulnar Joint Arthritis after Ulnar Shortening Osteotomy

Purpose: Ulnar shortening osteotmy is a common operation for the treatment of ulnar impaction syndrome. The purpose of this study was to evaluate factors that may affect the occurrence of distal radioulnar joint (DRUJ) arthritis after ulnar shortening osteotomy. Methods: From September 2005 to August 2012, we performed 81 ulnar shortening osteotomies for ulnar impaction syndrome, and evaluated occurrence or deterioration of DRUJ arthritis in 58 patients with a minimum follow-up of 1 year. We analyzed potential factors that may affect the occurrence of DRUJ arthritis, such as, age, sex, hand dominance, pre- and postoperative ulnar variance, preexisting DRUJ arthritis, types of radial sigmoid notch, amount of ulnar shortening, and follow up period. Results: DRUJ arthritis occurred or deteriorated in 32 out of the 58 patients. Regression analysis indicated a significant correlation between the type of radial sigmoid notch (type 1) and DRUJ arthritis. Other factors were not found to be correlated with occurrence or deterioration of DRUJ arthritis. Conclusion: This study suggests that patients with type 1 radial sigmoid notch (ulnar inclination of more than 10 degrees) are more likely to develop DRUJ arthritis after ulnar shortening osteotomy.

From Bench to Bedside: Preclinical Evaluation of a Self-Inactivating Gammaretroviral Vector for the Gene Therapy of X-linked Chronic Granulomatous Disease

Chronic granulomatous disease (CGD) is a primary immunodeficiency characterized by impaired antimicrobial activity in phagocytic cells. As a monogenic disease affecting the hematopoietic system, CGD is amenable to gene therapy. Indeed in a phase I/II clinical trial, we demonstrated a transient resolution of bacterial and fungal infections. However, the therapeutic benefit was compromised by the occurrence of clonal dominance and malignant transformation demanding alternative vectors with equal efficacy but safety-improved features. In this work we have developed and tested a self-inactivating (SIN) gammaretroviral vector (SINfes.gp91s) containing a codon-optimized transgene (gp91(phox)) under the transcriptional control of a myeloid promoter for the gene therapy of the X-linked form of CGD (X-CGD). Gene-corrected cells protected X-CGD mice from Aspergillus fumigatus challenge at low vector copy numbers. Moreover, the SINfes.gp91s vector generates substantial amounts of superoxide in human cells transplanted into immunodeficient mice. In vitro genotoxicity assays and longitudinal high-throughput integration site analysis in transplanted mice comprising primary and secondary animals for 11 months revealed a safe integration site profile with no signs of clonal dominance.

Genetic control of zinc and iron concentration in common bean seeds

The objective of this study was to obtain information regarding genetic control of zinc and iron levels in common bean seeds. For that purpose, four lines with high iron and zinc concentration and four with low concentration were crossed in a partial diallel design. Hybridizations were carried out in a greenhouse, as well as obtaining F1, reciprocal F1 and F2 generations. The data obtained were submitted to analysis of variance for each generation. To verify the occurrence of maternal effects, the possible contrasts between parents and F1 and reciprocal F1 generations were tested for each cross. It was observed that an expressive part of the variation in zinc and iron concentrations among the lines used is due to the seed coat. In the case of zinc, the additive allelic interaction alone explained the variation. For iron, the occurrence of dominance is also important. Key words: Phaseolus vulgaris L., maternal effect, combining ability, allelic interaction, nutritional quality.

Occurrence of thrushes in an urban fragment of Araucaria forest in southern Brazil

Seasonal segregation among syntopic species can be viewed as one of the available strategies for coexistence, reducing competitive process. The present work therefore aimed to interpret the assemblage structures comprising birds of the genus Turdus (Turdidae), through the analysis of seasonal variation in the species occurrence in a forest remnant located in the southcenter State of Paraná. Mist-netting was employed twice a month for capturing birds, totalling an annual effort of 7488 h.m². The frequency of occurrence, constancy and class of species dominance was determined, together with the parameters generally used in studies of ecological communities (richness, abundance, diversity and evenness). A total of 162 individuals were captured, representing five species. Turdus rufiventris was the most constant and frequent species. Turdus amaurochalinus and Turdus leucomelas were captured with variable constancies and frequencies along the seasons. Turdus amaurochalinus was also very common and may present an overlapping process between migrant and non-migrant individuals during spring. Turdus albicolis was considered accessory, whereas Turdus subalaris was only registered during the reproductive period. Hence, it was possible to observe that seasonal modifications occurred both in the frequency of occurrence and in the constancy and dominance of species. These results indicated the possibility of a lower use of the environment during the breeding season, as well as the presence of a higher number of individuals in summer and increased abundance of Turdus rufiventris and T. leucomelas during autumn and winter.

Climate‐induced change in biogenic bromine emissions from the Antarctic marine biosphere

Climate change and human activities are expected to have a major impact on the structure and functioning of marine ecosystems and the biogeochemical cycles they mediate in the coming years. Here we describe time series measurements of biogenic bromocarbons (CHBr3 and CH2Br2) collected in coastal waters of the western Antarctic Peninsula which is one of the world's most rapidly changing marine environments. Our measurements spanned a period of changing sea‐ice dynamics and phytoplankton community structure driven by climatic forcing. Specifically, the occurrence of high chlorophylla concentrations (≥5 μg L−1) and dominance of the largest phytoplankton size fraction (≥20 μm) indicating diatom bloom conditions was reduced following winter periods with a relatively short winter sea‐ice duration (&lt;50 days). While large inter‐annual variability in seawater CHBr3 concentrations was observed alongside these changes the same was not found for CH2Br2 which is surprising given their proposed common source. Seawater CHBr3 concentrations were found to be significantly higher (122 [14.7–580] pmol L−1, P &lt; 0.0001, Mann‐Whitney) in samples collected in diatom bloom compared to non‐bloom waters (42.9 [12.0–126] pmol L−1). A comparison of sea‐to‐air flux rates suggests that a switch from diatom bloom to non‐bloom conditions results in a factor of 3–4 decrease in average CHBr3sea‐to‐air emission rates which will reduce the supply of biogenic bromine to the atmosphere. Our calculations suggest that this will drive a decrease in inorganic bromine levels in the troposphere by a factor of 2–3 outside of ozone depletion events with potentially important implications for ozone cycling and dimethyl sulphide oxidation. This work has captured and crucially quantified the impact of a climate‐induced change in a marine ecosystem on ocean‐atmosphere biogeochemistry.

Allelochemical effect of Trianthema portulacastrum L. on Amaranthus viridis L. supports the ecological importance of allelopathy

The effect of allelopathy on many aspects of plant ecology including occurrence, growth, and structure of plant communities, dominance, and diversity has had a check red history among ecologists. Field studies showed the increase of Amaranthus viridis density in an infested area by Trianthema portulacastrum more than uninfested area, while no difference in soil physicochemical characters at both areas. Bioassay was done under two different temperatures 25 and 35°C with different types of T. portulacastrum leaf and stem extracts. The untreated seeds showed very small germination percent at the high temperature, while the treated seeds showed very high percentage. Different types of extracts had highly significant increase in seed germination, radicle and plumule growth of A. viridis. Treatment by T. portulacastrum extracts increased soluble protein, amylase and total phenol of A. viridis. Stimulation of all the previous parameters was higher in high temperature than in the lower. HPLC analysis for T. portulacastrum leaf and stem estimated eight phenolic compounds. The present study supports the ecological importance of allelopathy in Agriculture.

Meiotic silencing in the homothallic fungus Gibberella zeae

The homothallic ascomycete fungus Gibberella zeae is an important pathogen on major cereal crops. The objective of this study was to determine whether meiotic silencing occurs in G. zeae. Cytological studies demonstrated that GFP and RFP-fusion proteins were not detected during meiosis, both in heterozygous outcrosses and homozygous selfings. The deletion of rsp-1, a homologue used for studies on meiotic silencing of Neurospora crassa, triggered abnormal ascospores from selfing, but outcrosses between the mutant and wild-type strain resulted in some ascospores with mutant phenotype (low occurrence of ascus dominance). When the ectopic mutants that carried an additional copy of rsp-1 were selfed, they primarily produced ascospores with normal shape but a few ascospores (0.23 %) were abnormal, in which both endogenous and ectopically integrated genes contained numerous point mutations. The ectopic mutants showed low occurrence of ascus dominance in outcrosses with strains that carried the wild-type allele. Approximately 10 % of ascospores were abnormal but all of the single-ascospore isolates produced normal-shaped ascospores from selfing. However, no ascus dominance was observed when the mutants were outcrossed with a sad-1 deletion mutant, which lacks the putative RNA-dependent RNA polymerase essential for meiotic silencing in N. crassa. All results were consistent with those generated from an additional gene, roa, required for ascospore morphogenesis. This study demonstrated that G. zeae possesses a functional meiotic silencing mechanism which is triggered by unpaired DNA, as in N. crassa.

Dominant Party Regimes in Canada and Australia: Going the Way of the Dodo Bird?

Dominant party regimes – in which one and the same party controls government over an extended period of time, whether alone or as the major player in a coalition – are not as anomalous in Western democracies as it may appear to casual observers, especially if the subnational jurisdictions of federations are considered alongside national party systems. In our paper, we probe the incidence of dominant party regimes in the federally-organized parliamentary democracies of Canada and Australia. Although extant literature indicates that Europe provides a more favorable political environment to single-party dominance than Westminster systems, both countries have experienced phases of regular alternation in government as well as dominant party regimes (for instance, Social Credit and Conservative dominance in Alberta and Ontario, and Country/National Party dominance in Queensland). In the paper, we ask whether single-party dominance is now a phenomenon of the past and, if so, why this is the case. An original dataset comprising all national and subnational election results and government formation outcomes in the two countries since January 1, 1901 (the date of the formation of the Commonwealth of Australia) as well as a dataset of government episodes of varying length – defined by the identity of the sole or largest government party – are the empirical basis of our study. Our data indicate that single-party dominance occurs more often in the Canadian provinces than in the Australian states and that it may flourish under a variety of conditions. We also find that dominant party regimes mostly appear to be a thing of the past. Explaining the increasingly rare occurrence of single-party dominance requires the consideration of a number of structure and agency-related explanatory factors.