Temperature-induced variation in sexual maturation of Japanese anchovy Engraulis japonicus

2015 ◽  
Vol 95 (6) ◽  
pp. 1271-1276 ◽  
Author(s):  
Michio Yoneda ◽  
Masayuki Yamamoto ◽  
Tetsuo Yamada ◽  
Makoto Takahashi ◽  
Yasuhiro Shima

Temperature is one of the most influential factors for the sexual maturation of fishes, but understanding of the extent to which temperature affects the maturational schedules is limited in multiple-spawning fishes over a protracted season. This study examined the effect of temperature on sexual maturation of Japanese anchovy Engraulis japonicus siblings under high and low temperature regimes on different birthdates. The maturation probability differed between the two temperature regimes. Specimens in high temperature regimes matured at much smaller size and younger age than their counterparts. Also, a significant difference in the maturation probability between sexes was found at low temperatures, but not at high temperatures. Our findings show that temperature affects the maturational schedules of siblings of Japanese anchovy, suggesting that the size and age at sexual maturation could differ among cohorts, even in a given sampling location and/or year.

2019 ◽  
Vol 15 (2) ◽  
pp. 178-181
Author(s):  
Mohd Fadzil Awang ◽  
Alicia Mindy Anak Rogie ◽  
Hazilia Hussain ◽  
Nazri Che Dom

Aedes albopictus (Skuse) is known to be an invasive species and it becomes the main concern on the changes of climate that will cause the expansion and spreading of the mosquito populations. Therefore, this study was designed to determine the development cycles of Ae. albopictus larval at different water temperatures and water holding containers in a controlled environment by using temperature regulated water bath to cover a range of temperature from 25ºC to 35ºC. The experiment was completely randomized in factorial 3 x 5 design (15 treatments), three populations (Selangor-strain, Malacca-strain and Sabah-strain) and three replications. The analysis was based on the observation of the immature stages development (days) in response to different water temperature regimes and types of water containers. The development between three different strains showed no significant difference (p-value: 0.594), however the effect of water temperature on local strains showed that the temperature might shorten the development period of Ae. albopictus. This study concluded that the information on the larval development could act as a preliminary warning in recognizing the pattern of outcome due to seasonal changes throughout the year in Malaysia.


2013 ◽  
Vol 1 (2) ◽  
pp. 143
Author(s):  
Petrus P Letsoin ◽  
Henneke Pangkey ◽  
Julius Sampekalo ◽  
Inneke F.M Rumengan ◽  
Stenly Wullur ◽  
...  

The rotifer Brachionus rotundiformis (total body length 240.59±10.24 μm, lorica length 175.28±9.18 μm, and lorica width 124.28±7.76μm) is commonly used as starter food in the larval rearing of marine fish. But, larvae of some marine tropical fish species required starter food with body size smaller than B. rotundiformis. The present study was aimed to isolate minute rotifers from nature and to assess the possibility of culturing these rotifers. Sampling of rotifers was conducted in an estuary of Mangket (Kema-Minut), using plankton net (mesh size 40 µm). A trial of culturing the rotifers was conducted at salinities of 10, 20 and 30 ppt by using a microalga, Nannochloropsis oculata. A species of rotifer identified as Colurella sp. (family Lepadellidae) was successfully isolated from the sampling location. Body size of Colurella sp. was extremely small (Total length 123.22±5.45 μm, lorica length 95.96±3.81 μm, and lorica width 53.57±3.11 μm), which were smaller than Brachionus rotundiformis SS-type as a conventional starter food for marine fish larvae.  Results of culturing the minute rotifer Colurella sp. showed that the species grew well at salinities of 10, 20 and 30 ppt with no significant difference among treatments (ANOVA, p>0.05), indicating a potential use of minute rotifer Colurellasp. as starter food for marine fish larvae. Rotifera Branchionus rotundiformis (ukuran tubuh: panjang total 240,59±10,24 μm, panjang lorika 175,28±9,18 μm, dan lebar lorika 124,28±7,76μm) sering digunakan sebagai pakan awal pemeliharaan larva ikan laut. Namun, larva beberapa spesis ikan laut tropis membutuhkan pakan awal berukuran tubuh lebih kecil dari Branchionus rotundiformis. Penelitian ini bertujuan untuk mendapatkan minute rotifer dari alam (berukuran tubuh lebih kecil dari B. rotundiformis) dan menguji kemungkinan pemeliharaannya. Sampling rotifer dilakukan di perairan estuari Desa Mangket (Kema-Minut), menggunakan plankton net (ukuran mata jaring 40 µm). Uji coba pemeliharaan dilakukan pada salinitas (10, 20, dan 30 ppt) dengan menggunakan Nannochloropsis oculata. Satu spesies minute rotifer yang teridentifikasi sebagai Colurella sp. (family Lepadellidae) berhasil diisolasi dari lokasi sampling. Colurella sp. memiliki ukuran tubuh sangat kecil (panjang total [PT] 123,22±5,45 µm, panjang lorika [PL] 95,96±3,81 µm, dan lebar lorik [LL] 53,57±3,11 µm) yang mana lebih kecil dari Branchionus rotundiformis tipe-SS sebagai pakan awal larva ikan laut. Hasil uji coba pemeliharaan minute rotifer Colurella sp. menunjukkan bahwa spesis ini dapat tumbuh pada salinitas 10, 20, dan 30 ppt dengan perbedaan kepadatan populasi yang tidak signifikan antar perlakuan (Uji ANOVA, p > 0.05) mengindikasikan potensi pemanfaatan minute rotifer Colurella sp. sebagai pakan awal larva ikan laut.


2021 ◽  
Author(s):  
Rajaram Dhole ◽  
Ismael Ripoll ◽  
Sabesan Rajaratnam ◽  
Celine Jablonski

Abstract Pipelines are coated with insulating material that minimizes heat losses to the environment. Reeled pipe can experience nominal bending strain in the order of 1% to 2%. Thick coating on the pipe is inherently more highly strained, because of concentrations that occur at the interface between parent coating and field joint coating. Occasionally, contractors who specialize in pipe-lay using the reeling method have experienced difficulties relating to unexpected disbondment and cracks in coating at these interfaces. Any disbonded coating is routinely identified and repaired, but it is important to understand the influential factors that could lead to this type of coating disbondment. It is known in the industry that parameters such as temperature, reeling speed and pipe tension are influential but the relative influence of the factors is not well understood. In addition, there is currently no industry code or recommended practice that proposes the strain levels that the coating could safely withstand prior to cracking. This paper addresses thermo-mechanical aspects of coating design and presents a novel approach to quantify which parameters have the largest influence. In the presented assessments, coating strain was assessed using finite element analysis. Material input was selected from a combination of typical values and specific laboratory test results for polypropylene (PP) and injection molded polypropylene (IMPP). An essential aspect was that the mechanical and thermal properties of the PP were related to temperature and strain rate. Strain rates in the coating during reeling operations were obtained from global FE models. Detailed local FE models incorporated all the material and load inputs and temperature conditions that are necessary to determine peak strain values in the coating; the peak strain values would indicate the locations of potential coating disbondment. The study is purely a strain assessment and excludes any potential for defects or delamination in the coating that could result from its manufacturing process. This strain-based study revealed that coating temperature during reeling is the most influential factor on strain level in the coating. Reeling speed and pipe tension are parameters providing secondary influences.


1995 ◽  
Vol 198 (1) ◽  
pp. 137-140 ◽  
Author(s):  
A A Harper ◽  
I P Newton ◽  
P W Watt

The spontaneous cardiac pacemaker activity and conformation were recorded in vitro, using intracellular recording methods, from heart tissue of summer- and winter-caught plaice. The effects of changing temperature on the pacemaker rate, duration of action potential and diastolic depolarization were investigated by altering the temperature of the superfusing medium. The resting intrinsic rate of discharge was significantly greater in pacemaker cells from winter plaice (P=0.05), but there was no significant difference between winter and summer fish in the apparent Arrhenius activation energies for this process. However, there was a significant difference in the estimated intercept, indicating a thermal shift in the processes underlying the spontaneous pacemaker rhythm. There was no significant difference in the diastolic depolarization duration recorded from winter and summer fish over the temperature range 4­22 °C. The major effect of previous environmental temperature was on the duration of the action potential (P<0.02), indicating that the observed changes in pacemaker discharge rate were not influenced by the processes that determine the duration of the pacemaker diastolic depolarisation but were modulated by the channel events that give rise to the action potential.


2002 ◽  
Vol 68 (sup1) ◽  
pp. 234-237
Author(s):  
SATOSHI WATANABE ◽  
MOTOMITSU TAKAHASHI ◽  
YOSHIRO WATANABE

2021 ◽  
Vol 12 ◽  
Author(s):  
Lifeng Zhu ◽  
Wei Zhu ◽  
Tian Zhao ◽  
Hua Chen ◽  
Chunlin Zhao ◽  
...  

An increasing number of studies have shown that warming also influences the animal gut microbiome (altering the community structure and decreasing its diversity), which might further impact host fitness. Here, based on an analysis of the stomach and gut (the entire intestine: from the anterior intestine to the cloaca) microbiome in laboratory larva of giant salamanders (Andrias davidianus) under different living water temperatures (5, 15, and 25°C) at two sample time points (80 and 330 days after the acclimation), we investigated the potential effect of temperature on the gastrointestinal microbiome community. We found the significant Interaction between sampling time and temperature, or type (stomach and gut) on Shannon index in the gastrointestinal microbiome of the giant salamanders. We also found the significant difference in Shannon index among temperature groups within the same sample type (stomach or gut) at each sample time. 10% of variation in microbiome community could be explained by temperature alone in the total samples. Both the stomach and gut microbiomes displayed the highest similarity in the microbiome community (significantly lowest pairwise unweighted Unifrac distance) in the 25-degree group between the two sampling times compared to those in the 5-degree and 15-degree groups. Moreover, the salamanders in the 25°C treatment showed the highest food intake and body mess compared to that of other temperature treatments. A significant increase in the abundance of Firmicutes in the gastrointestinal microbiome on day 330 with increasing temperatures might be caused by increased host metabolism and food consumption. Therefore, we speculate that the high environmental temperature might indirectly affect both alpha and beta diversity of the gastrointestinal microbiome.


1965 ◽  
Vol 16 (1) ◽  
pp. 1 ◽  
Author(s):  
RD Asana ◽  
RF Williams

Experiments were conducted in controlled environments to determine the effects of high temperatures on grain development and yield in wheat. Two Australian and three Indian cultivars of wheat were exposed, from a week after anthesis until maturity, to "day" temperatures of 25, 28, and 3l°C, and "night" temperatures of 9 and 12°C. There was a mean reduction in yield of 16%' for the 6° rise in day temperature, but the cultivars did not differ significantly in their response to these temperatures. There were no significant effects of night temperature on grain weight, but stem weight was less at 12°C. Senescence was hastened only slightly by high day temperature, and there were no differential effects between cultivars in this respect.In a subsidiary experiment one Indian and five Australian cultivars were subjected to three day-night temperature regimes (24/19°, 27/22°, and 30/25°C). Highly significant but complex interactions were established between temperature regime and cultivar. A growth analysis for the Australian cultivars Ridley and Diadem indicated that the developing grain of Ridley had a greater capacity for growth than that of Diadem from the earliest stage. This, together with the confirmation of grain size as a very stable characteristic for all the varieties, points to the developmental and synthetic activity of the grain as an important determinant of grain yield. The relevance of this study to the production of wheat in India is briefly discussed.


2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Manal Almalik ◽  
Abeer Alnowaiser ◽  
Omar El Meligy ◽  
Jamal Sallam ◽  
Yusra Balkheyour

Objective. To determine anxiety in relation to gender, Grade Point Average (GPA), level of education and academic and clinical situations in Jeddah, Saudi Arabia. Also, to identify academic and clinical anxiety levels among postgraduate pediatric dentistry students. Methods. A cross-sectional study at governmental training hospitals was conducted. All registered postgraduate students in pediatric dental programs during the year 2015-2016 were included in the study. A self-administered questionnaire was distributed electronically to 60 postgraduate pediatric dentistry students aged between 25 and 45 years old. The questionnaire is composed of 55 questions that investigated demographic data, academic and clinical related situations including investigations, diagnosis, treatment, and complications in treatment. Results. The study showed a higher anxiety level in younger age dental students (76.7% compared to 23.3%) and Saudi board residents (60%). Comparing gender differences in anxiety revealed that a significant difference (P≤0.05) was found and anxiety seems to be more among female dental students (2% very anxious, 64% slightly anxious, and 34% not anxious) as compared to male dental students (8% very anxious, 69% slightly anxious, and 23% not anxious). Conclusions. There was increased awareness, detailed understanding, and handling of the patients by senior postgraduate pediatric dentistry students compared to junior students.


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