A comparative account of the reproductive cycles of five species of marine mussels (Bivalvia: Mytilidae) in the vicinity of Fremantle, Western Australia

1967 ◽  
Vol 18 (2) ◽  
pp. 175 ◽  
Author(s):  
BR Wilson ◽  
EP Hodgkin
Keyword(s):  
Reproductive Cycle ◽  
Western Australia ◽  
Marine Species ◽  
Spawning Season ◽  
Latitudinal Distribution ◽  
Marine Mussels ◽  
Reproductive Cycles ◽  
Determining Factor ◽  
Pacific Species

Descriptions are given of the reproductive cycles of five marine species of mussels. Two of these species have a southern Australian distribution and three are tropical Indo-Pacific species or have Indo-Pacific affinities. The reproductive cycles differ significantly, each species exhibiting a characteristic breeding pattern. A distinction is drawn between the season of gametogenic activity and the much narrower season of actual spawning. In four of the species the major features of the reproductive cycle correlate with latitudinal distribution. This is interpreted as evidence supporting the role of temperature as a principal determining factor in the control of broader aspects of the reproductive cycle (i.e. duration and season of gametogenic activity). Differences in finer details of the reproductive cycles (e.g. spawning season and number of spawning peaks) appear to be controlled by unknown factors besides temperature.

Reproduction and the Female Reproductive Cycle of Nyctophilus geoffroyi and N. major (Chiroptera: Vespertilionidae) from South-western Australia

1997 ◽  
Vol 45 (5) ◽  
pp. 489 ◽  
Author(s):  
D. J. Hosken
Keyword(s):  
Histological Examination ◽  
Reproductive Cycle ◽  
Western Australia ◽  
Reproductive Cycles ◽  
Reproductive Events ◽  
Vespertilionid Bats ◽  
Female Reproductive Cycle

The reproductive cycles of female Nyctophilus geoffroyi and N. major from south-western Australia are described from capture records and histological examination of tissue from fixed specimens. The sequence of reproductive events for both species was similar to that described for other vespertilionid bats from south- western Australia. Mating commenced between March and May. Sperm were stored in the caudal isthmus of the oviduct and in endometrial glands near the utero-tubal junction. Ovulation and fertilisation occurred in late August or September and twinning was common. Parturition occurred between late October and November, with volant young first captured during December, but it appeared not all N. geoffroyi females were reproductively active every year. Lactation had generally ceased by February, which was when the last detectably juvenile bats were captured.

scholarly journals Biomonitoring of Heavy Metals: The Unexplored Role of Marine Sessile Taxa

2021 ◽  
Vol 11 (2) ◽  
pp. 580
Author(s):  
Camilla Roveta ◽  
Anna Annibaldi ◽  
Afghan Afghan ◽  
Barbara Calcinai ◽  
Cristina Gioia Di Camillo ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Current Knowledge ◽  
Marine Species ◽  
Shallow Waters ◽  
Anthropogenic Inputs ◽  
Current Review ◽  
European Water ◽  
To Receive ◽  
Sessile Organisms

Coastal areas are known to receive significant anthropogenic inputs, mainly deriving from metropolitan areas, industries, and activities related to tourism. Among these inputs, some trace elements are listed as priority pollutants in the European Water Framework Directive, due to their ability to bioaccumulate in organisms. Many studies have been conducted on heavy metals (HMs) accumulation and on their possible effects on different edible marine species. While the most studied sessile organisms are bivalves, in the current review, we focus our attention on other sessile taxa (sponges, cnidarians, bryozoans, polychaetes, cirripeds, and tunicates), proposed as bioindicators in coastal shallow waters. Although their potential as bioindicator tools has been repeatedly highlighted in the literature, these organisms are still poorly investigated and considered for monitoring. In this context, we analyze the available literature about this topic, in order to summarize the current knowledge and identify possible applications of these organisms in a bioremediation scenario.

Youth Studies, Housing Transitions and the ‘Missing Middle’: Time for a Rethink?

2013 ◽  
Vol 18 (3) ◽  
pp. 118-129 ◽  
Author(s):  
Steven Roberts
Keyword(s):  
Young Men ◽  
Social Resources ◽  
Youth Studies ◽  
Transitions To Adulthood ◽  
Lack Of Fit ◽  
Youth Research ◽  
Communal Living ◽  
Missing Middle ◽  
Determining Factor

A recent but growing trend in studies of young people's lives has been to highlight that there is a ‘missing middle’ in the youth studies research agenda. It has been argued that much youth research focuses on either successful or very troubled transitions to adulthood, with the lives of those who might simply be ‘getting by’ representing an empirical absence. Building on previous work that has addressed how such a missing middle can add to our understanding of educational experience and attainment, labour market engagement and participation, and issues of identity, this paper pays attention to the housing transitions, careers and aspirations of a group of ‘ordinary’ and apparently unproblematic working class young men. Because they do not represent groups that have been of especial interest in youth studies to date, their experiences problematize the on-going utility of dominant conceptual frameworks used to explain housing transitions. In addition to their ‘lack of fit’ with ideal type typologies, the young men also reveal the shifting nature of attitudes towards communal living ‘which is traditionally associated with middle class students’ in combination with the continuing role of social resources as a determining factor in their housing transition.

An Investigation of the Role of the Hypothalamus in the Reproductive Cycle of the Cat

1966 ◽  
Vol 25 (2) ◽  
pp. 140-152 ◽  
Author(s):  
Earle E. Crandall ◽  
Robert C. Bahn ◽  
Edward C. Clark
Keyword(s):  
Reproductive Cycle

scholarly journals Rural or urban living and Parkinson's disease

1996 ◽  
Vol 54 (1) ◽  
pp. 37-41 ◽  
Author(s):  
Henrique B. Ferraz ◽  
Luiz A. F. Andrade ◽  
Vítor Tumas ◽  
Leandro C. Calia ◽  
Vanderci Borges
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Rural Area ◽  
Living Environment ◽  
Response To Treatment ◽  
Urban Group ◽  
Determining Factor ◽  
Rural Group

Although the precise etiology of Parkinson's disease (PD) is as yet unknown, it appears that certain environmental factors are involved. Prior living in a rural area has been implicated as a possible risk factor for PD, particularly in the early onset type. We evaluated the role of previous living conditions in the clinical correlates and outcome characteristics of 118 PD patients. All of them were seen from January 1987 to October 1992. The Rural Group (RG) comprised 71 patients (60.2%) who had lived in the rural area for at least 10 years (mainly in early phase of life) and the Urban Group (UG) consisted of 47 patients (39.8%) who had lived their entire life in an urban environment. The average age at the beginning of the symptoms was 58.8 in the RG and 54.1 in the UG. The mixed form of the disease (tremor, rigidity and akinesia) was the most frequent in both groups. A minimum 6-month follow-up period was undertaken with 63 patients (average 20 months) and no difference in response to treatment or in progression of the illness was detected between the two groups. Our data show that the previous living environment does not appear to be a determining factor in either the clinical or outcome characteristics of PD.

External Threat and Democracy: The Role of NATO Revisited

2006 ◽  
Vol 43 (4) ◽  
pp. 413-431 ◽  
Author(s):  
Douglas M. Gibler ◽  
Jamil A. Sewell
Keyword(s):  
Regime Type ◽  
Baltic States ◽  
Democratic Transitions ◽  
Territorial Sovereignty ◽  
External Threat ◽  
The Baltic ◽  
Threat Levels ◽  
Determining Factor ◽  
Former Soviet Republics

This article examines the role of NATO in aiding democratic transitions and survival in the former Soviet republics. The authors argue that the level of external threat is a determining factor in centralization, militarization, and ultimately regime type. States tend to be democratic or are likely to make the transition toward democracy when threat levels are low, while autocracies are more likely to be found in states targeted by higher levels of threat. Building on recent findings examining the link between democracies and alliance, the authors demonstrate that NATO has been an effective guarantor of territorial sovereignty and independence in the Baltic states, Ukraine, and Moldova, reducing the level of threat experienced by each state, thus assuring the survival of decentralized and democratic governments. Former Soviet republics targeted by high levels of threat have reverted to or maintained centralized, autocratic forms of government.

scholarly journals Acute melioidosis outbreak in Western Australia

1999 ◽  
Vol 123 (3) ◽  
pp. 437-443 ◽  
Author(s):  
T. J. J. INGLIS ◽  
S. C. GARROW ◽  
C. ADAMS ◽  
M. HENDERSON ◽  
M. MAYO ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Water Supply ◽  
Western Australia ◽  
Burkholderia Pseudomallei ◽  
Acute Infection ◽  
Exposure Period ◽  
Pfge Type ◽  
Chromosomal Dna ◽  
Potable Water Supply

A cluster of acute melioidosis cases occurred in a remote, coastal community in tropical Western Australia. Molecular typing of Burkholderia pseudomallei isolates from culture-confirmed cases and suspected environmental sources by pulsed-field gel electrophoresis (PFGE) of XbaI chromosomal DNA digests showed that a single PFGE type was responsible for five cases of acute infection in a community of around 300 during a 5 week period. This temporal and geographical clustering of acute melioidosis cases provided a unique opportunity to investigate the environmental factors contributing to this disease. B. pseudomallei isolated from a domestic tap at the home of an asymptomatic seroconverter was indistinguishable by PFGE. Possible contributing environmental factors included an unusually acid communal water supply, unrecordable chlorine levels during the probable exposure period, a nearby earth tremor, and gusting winds during the installation of new water and electricity supplies. The possible role of the potable water supply as a source of B. pseudomallei was investigated further.

scholarly journals Enhancement of aromatase activity by D-aspartic acid in the ovary of the lizard Podarcis s. sicula

Reproduction ◽  
2001 ◽  
pp. 803-808 ◽  
Author(s):  
L Assisi ◽  
V Botte ◽  
A D'Aniello ◽  
MM Di Fiore
Keyword(s):  
Amino Acids ◽  
Aspartic Acid ◽  
Reproductive Cycle ◽  
Catalytic Properties ◽  
Ovarian Tissue ◽  
Experimental Treatment ◽  
Tissue Homogenate ◽  
Aromatase Activity

The present study investigated the role of D-aspartic acid (D-Asp) in ovarian steroidogenesis and its effect on aromatase activity in the lizard, Podarcis s. sicula. It was determined that D-Asp concentrations vary significantly during phases of the reproductive cycle: they vary inversely with testosterone concentrations and directly with oestradiol concentrations in the ovary and plasma. Experimental treatment showed that administration of D-Asp induces a decrease in testosterone and an increase in oestradiol, and that treatment with other amino acids (L-Asp, D-Glu and D-Ala) instead of D-Asp has no effects. Experiments in vitro confirmed these results. Furthermore, these experiments showed an increase in aromatase activity, as the addition of D-Asp either to fresh ovarian tissue homogenate or to acetonic powder of ovarian follicles induced a significant increase in the conversion of testosterone to oestradiol. Aromatase activity is four times greater in the presence of D-Asp than in its absence. However, almost equivalent values of the two K(m) values (both approximately 25 nmol l(-1)) indicate that aromatase has the same catalytic properties in both cases.

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