The biology of the Water Rat Hydromys chrysogaster Geoffroy (Muridae: Hudromyinae) in Victoria.

1960 ◽  
Vol 8 (2) ◽  
pp. 170 ◽  
Author(s):  
J McNally
Keyword(s):  
Reproductive Tract ◽  
Late Summer ◽  
Early Spring ◽  
Female Rats ◽  
Late Winter ◽  
Adult Size ◽  
Population Turnover ◽  
In The Wild ◽  
Hydromys Chrysogaster ◽  
One Year

In the wild population of water rats studied, males were more numerous and larger than females. In a population of 589 water rats, 323 were males and 266 females. Whole weights ranged from 170 to 1275 g for males and 156 to 992 g for females. Males were age-grouped into adults (including subadults) and juveniles on the basis of combined testes weights. Sexual maturity is reached when a whole weight of between 400 and 600 g (14-21 oz) is attained. Females were age-grouped on the stage of maturity of the reproductive tract. Female rats can reproduce when a whole weight of 425 g (15 oz) is attained. Mating takes place in late winter and continues through spring. The breeding season extends from September to January, with the peak in early spring. Females are in anoestrus in late summer, autumn, and early winter. The number in each litter varies from one to seven: the usual number is four or five. Growth is rapid; young can reach adult size in less than one year. The structure of the population varies throughout the year. The proportion of adults (including subadults) is high in winter and spring and falls in summer and autumn when juveniles appear in numbers. The fecundity of water rat's is lower than normal for murid species, but fertility is high and a substantial population turnover occurs each year when conditions for breeding are favourable. It is considered therefore that the water rat has potentiality for management as an economic fur-bearing animal.

scholarly journals Characterising terrestrial influences on Antarctic air masses using Radon-222 measurements at King George Island

2014 ◽  
Vol 14 (18) ◽  
pp. 9903-9916 ◽  
Author(s):  
S. D. Chambers ◽  
S.-B. Hong ◽  
A. G. Williams ◽  
J. Crawford ◽  
A. D. Griffiths ◽  
...  
Keyword(s):  
Late Summer ◽  
Early Spring ◽  
Late Winter ◽  
South American ◽  
King George Island ◽  
Air Masses ◽  
Diurnal Cycles ◽  
Baseline Values ◽  
One Year ◽  
Radon Measurements

Abstract. We report on one year of high-precision direct hourly radon observations at King Sejong Station (King George Island) beginning in February 2013. Findings are compared with historic and ongoing radon measurements from other Antarctic sites. Monthly median concentrations reduced from 72 mBq m−3 in late-summer to 44 mBq m−3 in late winter and early spring. Monthly 10th percentiles, ranging from 29 to 49 mBq m−3, were typical of oceanic baseline values. Diurnal cycles were rarely evident and local influences were minor, consistent with regional radon flux estimates one tenth of the global average for ice-free land. The predominant fetch region for terrestrially influenced air masses was South America (47–53° S), with minor influences also attributed to aged Australian air masses and local sources. Plume dilution factors of 2.8–4.0 were estimated for the most terrestrially influenced (South American) air masses, and a seasonal cycle in terrestrial influence on tropospheric air descending at the pole was identified and characterised.

scholarly journals Characterising terrestrial influences on Antarctic air masses using radon-222 measurements at King George Island

2014 ◽  
Vol 14 (8) ◽  
pp. 11541-11576 ◽  
Author(s):  
S. D. Chambers ◽  
S.-B. Hong ◽  
A. G. Williams ◽  
J. Crawford ◽  
A. D. Griffiths ◽  
...  
Keyword(s):  
Late Summer ◽  
Early Spring ◽  
Late Winter ◽  
South American ◽  
King George Island ◽  
Air Masses ◽  
Diurnal Cycles ◽  
Baseline Values ◽  
One Year ◽  
Radon Measurements

Abstract. We report on one year of high precision direct hourly radon observations at King Sejong Station (King George Island) beginning in February 2013. Findings are compared with historic and ongoing radon measurements from other Antarctic sites. Monthly median concentrations reduced from 72 mBq m−3 in late summer to 44 mBq m−3 in late-winter and early-spring. Monthly 10th percentiles, ranging from 29 to 49 mBq m−3, were typical of oceanic baseline values. Diurnal cycles were rarely evident and local influences were minor, consistent with regional radon flux estimates one tenth of the global average for ice-free land. The predominant fetch region for terrestrially influenced air masses was South America (47–53° S), with minor influences also attributed to aged Australian air masses and local sources. Plume dilution factors of 2.8–4.0 were estimated for the most terrestrially influenced (South American) air masses, and a seasonal cycle in terrestrial influence on tropospheric air descending at the pole was identified and characterised.

scholarly journals Sexual maturation in Atlantic salmon male parr may be triggered both in early spring and late summer under standard farming conditions

2021 ◽  
Author(s):  
Elia Ciani ◽  
Kristine von Krogh ◽  
Rasoul Nourizadeh-Lillabadi ◽  
Ian Mayer ◽  
Romain Fontaine ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Sexual Maturation ◽  
Late Summer ◽  
Early Spring ◽  
Plasma Testosterone ◽  
Farmed Salmon ◽  
Early Maturing ◽  
Advanced Stages ◽  
One Year ◽  
Immature Fish

AbstractMale Atlantic salmon (Salmo salar) display different sexual strategies, maturing either as parr during the freshwater phase (as sneaky spawners), or as post smolts following one or several years at sea. First sexual maturation (puberty) occurs at different times depending on environmental and genetic factors. To improve our knowledge on the timing (age and season) of first sexual maturation in Atlantic salmon male parr, we investigated pubertal activation in second generation farmed salmon from the Norwegian river Figgjo, reared under natural conditions of photoperiod and water temperature. Histological analysis, in combination with morphometric measurements, plasma androgen levels and pituitary gonadotropin gene expression analysis revealed that, as previously reported, some male parr initiated early sexual maturation in spring at one year of age. Interestingly, some male parr were observed to initiate sexual maturation already in autumn, six months after hatching (under-yearlings), much earlier than reported in previous studies. One-year old maturing males showed a low induction in gonadotropin levels, while under-yearling maturing males displayed a significant increase in fshb transcripts as compared to immature fish. Plasma testosterone, detectable also in immature males, increased constantly during testes development, while 11-ketotestosterone, undetectable in immature and early maturing males, increased during more advanced stages of maturation. A mild feminization of the testes (ovotestes) was detected in a subset of samples. This study brings new knowledge on the little investigated field of sexually maturing under-yearlings in Atlantic salmon. This is also the first study comparing the physiology of under-yearling vs one-year old maturing male parr, thus bringing new insights to the remarkable plasticity of Atlantic salmon puberty.

scholarly journals Human Sapovirus among Outpatients with Acute Gastroenteritis in Spain: A One-Year Study

Viruses ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 144 ◽  
Author(s):  
Miguel F Varela ◽  
Enrique Rivadulla ◽  
Alberto Lema ◽  
Jesús L Romalde
Keyword(s):  
Acute Gastroenteritis ◽  
Age Groups ◽  
The Elderly ◽  
Mean Value ◽  
Early Spring ◽  
Clinical Samples ◽  
Late Winter ◽  
Viral Pathogen ◽  
One Year ◽  
Different Strains

Viral agents of human gastroenteritis affect people of all ages across the globe. As a mainly self-limiting disease, it is difficult to evaluate the real prevalence of etiological agents circulating in each region. Many of the analyzed outbreaks are caused by viruses of the family Caliciviridae, especially the genus Norovirus (NoV). Most studies have focused on other enteric viruses, leaving sapovirus (SaV) underestimated as an important emerging human threat. This one-year study analyzed clinical samples from hospital outpatients with acute gastroenteritis in Spain, with the aim of revealing the importance of human SaV as an emerging viral pathogen. A total of 2667 stools were tested using reverse transcription (RT)-qPCR to detect and quantify SaV. Sapovirus was detected in all age groups, especially in infants, children, and the elderly. The prevalence was 15.64% (417/2667), and was slightly higher in 0–2- and 3–5-year-olds (19.53% and 17.95%, respectively) and much lower in 13–18-year-olds (9.86%). Positive samples were detected throughout the year, with peaks of detection during autumn and the late winter to early spring months. The mean value for the quantified samples was 6.5 × 105 genome copies per gram of stool (GC/g) (range 2.4 × 103–6.6 × 1011 GC/g). RT-nested PCR and sequencing were used for further genotyping. Genetic characterization showed a predominance of genogroup I (GI), followed by GII and GIV. The detection of multiple genotypes suggests the circulation of different strains without any clear tendency. The results obtained suggest SaV as the second major gastroenteritis agent after NoV in the region.

The rumenitis and liver abscess complex and vitamin A status in beef cattle

1970 ◽  
Vol 12 (2) ◽  
pp. 291-298
Author(s):  
A. C. Rowland
Keyword(s):  
Vitamin A ◽  
Late Summer ◽  
Early Spring ◽  
Agglutination Test ◽  
Late Winter ◽  
Liver Lesions ◽  
Seasonal Incidence ◽  
Vitamin A Status ◽  
The Mean ◽  
Intensively Managed

SUMMARYThe seasonal incidence of rumen and liver lesions is recorded in traditional and in intensively managed cattle, together with the vitamin A status of the two groups. Rumen lesions were observed to reach a peak in the late winter and early spring in traditional cattle, at which time the liver vitamin A levels fell to the lowest point; liver lesions reached a peak in the late summer. No specific trend was observable in rumen and liver lesions in the barley beef group. The mean levels of vitamin A were approximately one-third of those shown by the traditionally managed animals.It did not prove possible using the agglutination test to identify the sera of animals showing active hepatic necrobacillosis at the time of slaughter.

The dynamics of Trifolium repens in a permanent pasture I. The population dynamics of leaves and nodes per shoot axis

1989 ◽  
Vol 237 (1287) ◽  
pp. 133-173 ◽  
Keyword(s):  
Spatial Variation ◽  
Trifolium Repens ◽  
Death Rate ◽  
Birth Rate ◽  
Soil Surface ◽  
Early Spring ◽  
Late Winter ◽  
Seasonal Fluctuations ◽  
Permanent Pasture ◽  
One Year

The framework is developed for a formal quantitative analysis of the vegetative dynamics of Trifolium repens , based on partitioning the components of its growth. The method is used to describe the vegetative dynamics of T. repens in one pasture during the course of one year. Seasonal and spatial variation were analysed by regression on several environmental variables. The present paper includes only a partial analysis, covering the dynamics of leaves and nodes per shoot axis. The remainder of the analysis will be presented in subsequent papers. The production of modules per shoot axis, and the subsequent mortality of leaves, and burial and mortality of nodes, showed different patterns of spatial and seasonal variability, and different types of response to the environment. There was much seasonal and little spatial variation in rates of birth, burial and death of leaves and nodes. In contrast, there was relatively little seasonal and much spatial variation in the numbers of leaves and nodes, even though these numbers are determined by present and past births and deaths. The rate of production of leaves by individual apices varied from 0.01 per day to 0.19 per day. It appeared to be determined largely by temperature, probably of the apex, but also to some extent by genotype. Leaves survived for 1-21 weeks. The risk of leaf mortality varied with the age of the leaf, the number of sheep in the field, and the season. Leaves born in November tended to live longest, and those born in summer with many sheep shortest. At least 56% of leaves were utilized by sheep, the remainder dying from other causes. Seasonal fluctuations in death rate of leaves tended to lag three weeks behind fluctuations in birth rate, but with additional fluctuations caused by changes in grazing. The lag caused there to be a minimum of 1-5 leaves per axis in January, and a maximum of 3-12 in August, although at all times the number of leaves was increasing on some axes and decreasing on others. Axes were progressively buried by worm casts and leaf litter within 0-39 weeks of birth. The rate of burial appeared to be determined largely by earthworm activity and by treading by sheep. In autumn and early spring, nodes and internodes were buried faster than new ones were born. As a result, as few as three internodes were exposed on average in March, compared with a maximum mean of 20 in August. By late winter, some axes were entirely buried and started to grow vertically upwards towards the soil surface. Nodes survived for 14-85 weeks, the mean longevity being 51 weeks. On average, each axis bore 25 nodes, with a range of 10-49 nodes. Seasonal fluctuations in death rate lagged some 4-8 weeks behind those in birth rate. Survivial of nodes and internodes was dependent on the establishment and survival of roots. When the oldest rooted node on an axis died, all of the axis between it and the next rooted node also died. The development of pseudo-taproots increased the longevity of nodes by 100 days. Leaves had much shorter lives than their nodes. The ‘average’ shoot axis bore 3.5 nodes with leaves, 4.2 nodes still visible but without leaves, and 17.6 nodes buried beneath worm casts and litter.

scholarly journals Florida Edible Garden Plants: Hops (Humulus lupulus)

EDIS ◽  
2013 ◽  
Vol 2013 (10) ◽  
Author(s):  
Brian J. Pearson
Keyword(s):  
Late Summer ◽  
Early Spring ◽  
Humulus Lupulus ◽  
Home Garden ◽  
Fact Sheet ◽  
Climbing Plants ◽  
Early Fall ◽  
Garden Plants ◽  
One Year

Hops are perennial, herbaceous climbing plants commonly cultivated for their strobiles or cones (Figure 1). The cones are often used for flavoring and aroma in food, tea, and beer (Burgess 1964). Hops can make a unique addition to a home garden or landscape. It grows rapidly in the early spring to late summer. Plants reach a mature height of 18–25 feet in one year and produce cones from mid-summer to early fall. This 2-page fact sheet was written by Brian J. Pearson, and published by the UF Department of Environmental Horticulture, October 2013. http://edis.ifas.ufl.edu/ep488

The biology of Harveyella mirabilis (Cryptonemiales, Rhodophyceae). IV. Life history and phenology

1976 ◽  
Vol 54 (3-4) ◽  
pp. 281-292 ◽  
Author(s):  
Lynda J. Goff ◽  
Kathleen Cole
Keyword(s):  
Water Temperature ◽  
Seawater Temperature ◽  
Environmental Parameters ◽  
Late Summer ◽  
Early Spring ◽  
Day Length ◽  
Late Winter ◽  
Temperature Sensitive ◽  
The North ◽  
The North Pacific

A 20-month field study of the reproductive biology of the parasitic red alga Harveyella mirabilis was undertaken to investigate the effects of environmental parameters on the reproductive periodicity of Harveyella in the intertidal habitat. In the northeast Pacific, tetraspores have been observed in the late winter - early spring; apparently they are produced in response to increased available sunlight and water temperature. Gametogenesis appears to be temperature sensitive; it occurs between a narrow temperature range (9–11 °C). Carpospores are produced in the late summer when both water temperature and day length reach a peak. The phenology of H. mirabilis in the North Atlantic differs from that which is observed in the North Pacific in the timing of gametogenesis and carposporogenesis. The significance of this is discussed in relation to the possible effects of differences in seawater temperature on gametogenesis.

Seasonality and global public interest in psoriasis: an infodemiology study

2019 ◽  
Vol 96 (1133) ◽  
pp. 139-143 ◽  
Author(s):  
Qian Wu ◽  
Zhiwei Xu ◽  
Yi-Lin Dan ◽  
Chan-Na Zhao ◽  
Yan-Mei Mao ◽  
...  
Keyword(s):  
New Zealand ◽  
Public Interest ◽  
Seasonal Pattern ◽  
Late Summer ◽  
Early Spring ◽  
Late Winter ◽  
Search Volume ◽  
Early Autumn ◽  
Search Data ◽  
Google Search

ObjectiveAlthough patients with psoriasis frequently report seasonal changes in their symptoms, the seasonality of psoriasis has rarely been explored. This study aims to investigate the seasonal pattern of and global public interest in psoriasis using Google search data.MethodsInternet search data were collected from Google Trends. Data on the relative search volume (RSV) from January 2004 to December 2018 were retrieved using the term psoriasis. Cosinor analyses were conducted to examine the seasonality of psoriasis using data from two southern hemisphere countries (Australia and New Zealand) and four northern hemisphere countries (USA, Canada, UK and Ireland).ResultsOverall, searches for psoriasis steadily decreased between 2004 and 2010, and then rose from 2011 to 2018. On cosinor analyses, RSV of ‘psoriasis’ displayed a significant seasonal variation worldwide (p<0.025). Further analyses confirmed the seasonality of psoriasis-related RSV in Australia, New Zealand, USA, Canada, UK and Ireland (p<0.025 for all), with peaks in the late winter/early spring months and troughs in the late summer/early autumn months. The top 11 rising topics were calcipotriol/betamethasone dipropionate, ustekinumab, apremilast, shampoo, eczema, guttate psoriasis, seborrhoeic dermatitis, dermatitis, psoriatic arthritis, atopic dermatitis and arthritis.ConclusionThere was a significant seasonal pattern for psoriasis, with peaks in the late winter/early spring and troughs in the late summer/early autumn. Further studies are warranted to confirm the seasonal pattern of psoriasis using clinical data and to explore the underlying mechanisms.

Seasonal changes in the germination responses of seeds of Veronica peregrina during burial, and ecological implications

1983 ◽  
Vol 61 (12) ◽  
pp. 3332-3336 ◽  
Author(s):  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Seasonal Changes ◽  
Natural Habitat ◽  
General Pattern ◽  
Late Summer ◽  
Early Spring ◽  
Late Winter ◽  
Seasonal Temperature ◽  
Light In August ◽  
Late Autumn ◽  
Response To Temperature

Seeds of Veronica peregrina collected from a field population in central Kentucky were buried in soil and exposed to seasonal temperature changes. Fresh seeds and those exhumed after 1–26 months were tested in light and darkness at five thermoperiods simulating those in the natural habitat from early spring through late autumn. Freshly matured seeds were dormant, but they came out of dormancy in June and July and germinated to 98–100% in light in August at thermoperiods of 20:10, 25:15, 30:15, and 35:20 °C. Seeds retained the ability to germinate to high percentages at these temperatures until late winter and spring, but they never germinated to high percentages in darkness. Thus, in the natural habitat in July and August germination is prevented only by darkness and (or) insufficient soil moisture. At simulated habitat temperatures, seeds germinated to 88–100% in March and April but to only 21–69% in May and June. Seeds incubated at 15:6 °C showed a decline in germination percentages in late summer and autumn and an increase during late autumn and winter. The same general pattern of seasonal changes in germination response to temperature occurred during the 2nd year of burial.

Sign in / Sign up

Export Citation Format

Share Document