Polymorphism in Velacumantus australis (Gastropoda : Potamididae) and its relationship to parasitism

1966 ◽  
Vol 14 (1) ◽  
pp. 49 ◽  
Author(s):  
WH Ewers ◽  
CR Rose

Velacumantus australis is a common gastropod along the Australian coast. Samples of four populations were examined and the frequency of two banded forms was recorded. All brown-banded snails were small juveniles and these apparently die before reaching adolescence. White-banded snails occurred in all age groups and their frequency tends to be highest in juveniles and lowest in the oldest adults. White-banded snails have a much lower incidence of larval trematode infection than unbanded snails and also differ slightly in weight and in the onset of sexual maturity. It is suggested that these forms are maintained as a selectively balanced polymorphism.

2021 ◽  
Author(s):  
Shixiao Dong ◽  
Deyu Huang ◽  
Zheng Wang ◽  
Guanyou Zhang ◽  
Fengjuan Zhang ◽  
...  

Abstract Rotavirus was the an important causative agent of acute gastroenteritis in children. In China, rotavirus was positive in approximately 30% of the diarrhea children and become a serious public problem. This study was carried out to investigate the clinical and molecular epidemic characterization of rotavirus infection among children under 5 years old with acute diarrhea in Shandong province, China. From July 2017 to June 2018, a total of 1211 fecal specimens were detected and the prevalence of rotavirus infection was 32.12%. The mean age of positive children was 12.2 ± 10.9 months and the highest infection rate was observed in children aged 7–12 months with a rate of 41.64%. G9P[8] (76.61%) was the most prevalent combinations followed by G2P[4] (7.20%), G3P[8] (3.60%) and G9P[4] (2.06%). In addition to diarrhea, vomiting, fever and dehydration were the most common accompanied symptoms. In general, there was no significant difference in clinical manifestations among different age groups. However, the clinical manifestations between vaccinated and unvaccinated children were significantly different. Vaccinated children showed lower incidence and frequency of vomiting, lower incidence and degree of dehydration, lower incidence of severe cases than unvaccinated children. The findings suggested necessary to continue rotavirus strains surveillance in order to monitor the change of prevalent genotype. Moreover, introducing vaccine into national immunization program to prevent and control rotavirus infections is needed in China.


Author(s):  
G. A. Steven

The first serious attempt to determine the age and growth rate of the common mackerel (Scomber scombrus L.) appears to have been made by Captain Atwood in 1856 (quoted by Brown Goode, 1884, p. 116) in the Massachusetts Bay area of northern North America. Small fish caught by Atwood in October of that year measuring 6½–7 in. in length (16.5–17.5 cm.) he believed to be the young of the year (i.e. they belonged to the O-group). Mackerel belonging to this group he calls ‘spikes’. ‘Blinks', ‘tinkers’ and ‘second size’ fish he assigns to the I-, II- and III-year age groups respectively, but unfortunately gives no data as to the sizes of those categories, merely stating that everyone well acquainted with mackerel makes the same groupings ‘as there seems to be a line of demarkation between the different kinds which stands out prominently’. Sixteen years later, on 27 July 1872, Malm (1877, p. 409) observed large numbers of small mackerel close inshore in the Gullmarfjord near Christineberg. Several tons of those mackerel were enclosed in a seine, but only ten specimens were retained as all the others escaped through the meshes. These ten fish ranged in length from 67 to 100 mm. and Malm surmised their age to be 13 months. Collett (1880, p. 18) stated that on the coast of Norway I-year-old mackerel are ‘fingerlang’. To fish of 20 cm., taken at the end of August, he ascribed (without supporting data) an age of 2 years, with sexual maturity supervening at 3 years at an unspecified length.


2018 ◽  
Vol 65 (4) ◽  
Author(s):  
Arif Parmaksız ◽  
Ahmet Oymak ◽  
Necmettin Dogan ◽  
Erhan Unlu

Maturity, growth and reproductive characteristics of the mossul bleak Alburnus mossulensis, from Ataturk Dam Lake (Euphrates) were assessed. Maturity composition of the analysed samples varied between age groups I and VII. The ratio of females to males was 1.047:1. Fork length of the samples varied between 40-198 mm and weights were in the range of 0.45-68 g. The regression equations derived for the length-weight relationship was Log W = -5.5531+3.2958 Log FL (r2=0.9593) for females and Log W=-5.3695+3.2112 Log FL (r2=0.9487) for males. Mean condition factor was determined as 1.069 for females and 1.062 for males. Absolute fecundity was established to be between 288 and 3380. The age of sexual maturity was 3 years in females and 2 years in males.


2009 ◽  
Vol 55 (5) ◽  
pp. 350-356 ◽  
Author(s):  
Yunzhi Yan ◽  
Lili Guo ◽  
Xiuying Xiang ◽  
Yilong Xi ◽  
Yifeng Chen

Abstract Breeding strategies of Acrossocheilus fasciatus were studied from 592 specimens collected monthly during May 2007 and April 2008 in the Puxi Stream of the Huangshan Mountain. Sex ratio of the studied population was 0.90 : 1 (♀ : ♂), not significantly different from 1:1. Both sexes reached their first sexual maturity at age 2 (the second calendar year of their birth). Fifty percent of females and males reached maturity at a total length of 69.75 mm and 69.36 mm respectively, and the minimum total length was 61.54 mm and 58.96 mm, respectively. Based on the monthly changes in gonado-somatic index and egg-development process, the breeding season of the population was from May to August, with one obvious interval (in June) occurring in the breeding activity for the females. The nonsynchronous development of oocytes observed in mature ovaries indicated that A. fasciatus is a batch spawner. Absolute fecundity of A. fasciatus ranged from 308 to 2002 eggs with a mean of 857 eggs, increased significantly with total length, and was significantly different among three age groups. Relative fecundity ranged from 38.63 to 71.70 egg/g with a mean of 53.29 egg/ g, and was not significantly different among the three age groups. It was suggested that these reproductive characteristics were adaptive strategies for A. fasciatus to acclimatize to lotic water where environmental factors were unstable but predictable.


2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 8019-8019
Author(s):  
Thierry Facon ◽  
Holger W. Auner ◽  
Maria Gavriatopoulou ◽  
Sosana Delimpasi ◽  
Maryana Simonova ◽  
...  

8019 Background: Multiple myeloma (MM) typically affects older populations, which are more vulnerable to toxicity with anti-MM treatments. These patients (pts) have significant morbidity and mortality, resulting in a need for dose modifications or alternative suboptimal treatment options. Significant improvements were observed in the BOSTON study with XVd vs Vd in median progression-free survival (PFS), overall response rate (ORR), and rates of peripheral neuropathy (PN); median overall survival (OS) trended in favor of XVd. Methods: The phase 3 randomized BOSTON trial (NCT03110562) is a controlled, open-label study of once weekly XVd vs. twice weekly standard Vd in pts with MM and 1-3 prior treatment regimens. We performed post-hoc analyses to compare survival benefits in pts ≥65 vs < 65 years of age. Results: The BOSTON study enrolled a total of 402 pts between June 2017 and February 2019 that were randomized into XVd or Vd arms. The numbers of pts treated with XVd or Vd who were ≥65 were 109/132 and 86/75 who were < 65, respectively. Baseline characteristics were similar by age although pts ≥65 years were less likely to have received ASCT than those < 65 years (48.4% vs. 25.3%). Median PFS was prolonged with XVd compared with Vd, across both age groups: ≥65 (HR, 0.55 [95% CI, 0.37-0.83] P = 0.002) and < 65, (HR, 0. 74 [95% CI, 0.49-1.11], P = 0.07). Vd was associated with a lower ORR (64.4%) than treatment with XVd (76.1%) (OR, 1.77 [95% CI, 1.00-3.11], P = 0.024) in pts ≥65, while the ORR in those < 65 was 76.7% with XVd and 58.7% (OR, 2.33 [95% CI, 1.18-4.59], P = 0.007) with Vd. As of Jan 2021, the median OS for the overall population was not reached for both arms (HR = 0.86; p = 0.193), with 61 and 75 deaths in the XVd and Vd arms, respectively. Median OS was not reached in pts ≥65 with XVd and was 28.6 months with Vd (HR = 0.60; 95% CI, 0.38-0.94; p = 0.012), while there was no difference in the OS for pts < 65 (HR = 1.52; 95% CI, 0.86-2.68; p = 0.926). Pts ≥65 had a lower incidence of death with XVd as compared to Vd (29 vs 56) and there were 32 deaths with XVd and 19 with Vd in pts < 65. Grade ≥3 treatment-emergent adverse events were not observed more often in older compared to younger pts. Amongst pts ≥65, PN of any grade was lower with XVd (32.1%) compared to Vd (46.5%); (OR 0.57 [95% CI 0.34-0.97], p = 0.017), including a lower incidence of grade ≥3 PN (XVd 4.6% vs. Vd 11.6%). Pts < 65 followed a similar trend of PN AEs of any grade: XVd, 32.6%; Vd, 48.0% (OR 0.42 [95% CI 0.21-0.82], p = 0.006). Conclusions: In an older patient population with a poor prognosis, XVd was associated with a significant survival benefit, improved PFS and OR with reduced PN, and requires relatively short and infrequent clinic visits. XVd may be a simple, effective regimen for pts ≥65 years of age. Clinical trial information: NCT03110562.


1976 ◽  
Vol 54 (2) ◽  
pp. 156-161 ◽  
Author(s):  
C. L. Glenn ◽  
R. R. G. Williams

Age at sexual maturity, seasonal gonadal development, and fecundity estimates of mooneye were determined from 695 samples captured in the Assiniboine River between November 17, 1972, and November 2, 1973. Most mooneye became sexually mature in their 4th (III +) or 5th (IV +) year of life, with more males mature at age III + than females. During 1973, spawning began after May 8 and was completed by June 12. The peak spawning activity occurred during mid-May when water temperatures ranged from 10 to 13 °C. All age groups of sexually mature females had rapid ovarian development during the summer months with about 80% of maximum ovarian weight present by October 17. Ripe ova have a mean diameter of 1.98 ± 0.07 mm. The mean annual total fecundity of Assiniboine River mooneye was about 5000–9000 ova per female. The mean annual relative fecundity was about 2000–2400 ova per 100 g body weight.


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