Triploid Atlantic salmon and triploid Atlantic salmon × brown trout hybrids have better freshwater and early seawater growth than diploid counterparts

The use of reproductively sterile triploid salmonids would enhance the environmental sustainability of the aquaculture industry by preventing genetic exchange between escapees and wild conspecifics. To this end, we assessed smoltification and early seawater performance (241 days) following a yearling production cycle (i.e. spring smolts) in diploid and triploid female Atlantic salmon (Salmo salar) × male brown trout (Salmo trutta) hybrids compared to purebred diploid and triploid salmon. During freshwater rearing (n = 180/group), hybrids demonstrated a degree of bimodality in body size, significantly (p < 0.05) more so in diploid than triploid hybrids (11 and 37% in the lower mode, respectively) that was not seen in purebred salmon of either ploidy. This resulted in diploid hybrids being 66% smaller on average at sea transfer, whereas no hybridisation effect was seen in triploids, and both triploid groups were significantly heavier (16–43%) than diploid salmon. Irrespective of ploidy, lower mode hybrids grew poorly and showed low survival in seawater, suggesting they had failed to undergo smoltification. However, the upper mode diploid hybrids showed a similar Na+/K+-ATPase (NKA) enzyme activity surge during the spring as in diploid and triploid salmon, despite a higher ratio of the freshwater to seawater mRNA abundance of the NKA subunits (nkaα1a and nkaα1b) and a reduced plasma cortisol surge. At the end of the experimental period, both hybrids weighed significantly less than their salmon counterparts although the hybrid effect was again greater in diploids (71% smaller) than triploids (6% smaller). In addition, both triploid groups were on average heavier (15–22%) than diploid salmon. As such, both triploid Atlantic salmon and triploid hybrids can show enhanced growth performance from juveniles up to post-smolts compared to diploid salmon in an aquaculture setting.publishedVersio

ANALISIS KEMAMPUAN BERFIKIR ALJABAR DI KELAS VII SMP NEGERI 1 KRANGKENG KABUPATEN INDRAMAYU (Studi Survei di Kelas VII Tahun Akademik 2012/2013)

Setiati Rahayu, 2013. Analisis Kemampuan Berfikir Aljabar di Kelas VII di SMP Negeri 1 Krangkeng Kab. Indramayu (Studi Survei di Kelas VII Tahun Akademik 2012/2013) Untuk mengukur kemampuan berfikir aljabar seorang siswa diperlukan beberapa indikator. Terdapat beberapa indikator untuk memahami aljabar diantaranya memahami pengertian koefisien variabel suku sejenis, kemampuan melakuakan operasi hitung, kemampuan mengggunakan simbol matematika, kemampuan menggunakan bahasa sehari-hari, kemampuan menyederhanakan operasi aljabar, kemampuan menyatakan berbagai hubungan, kemampuan menggunakan diagram alur dan memahami konsep aljabar invers. Tujuan dalam penelitian ini untuk menganalisis kemampuan berfikir aljabar di kelas VII yang ditinjau dari operasi aljabar, penggunaan aljabar, masalah aljabar, dan pemahaman konsep aljabar saat menjawab soal-soal aljabar. Kemampuan siswa dalam memahami aljabar merupakan suatu kondisi yang terdapat dalam sekolah SMP tersebut. Aljabar adalah suatu cabang ilmu matematika yang menggunakan tandatanda dan huruf-huruf yang mewakili angka-angka. Banyaknya indikator yang menjadi indikator kemampuan aljabar, maka akan ada beberapa indikator yang akan menjadi komponen utama dalam kemampuan aljabar. Untuk mengetahui kemampuan siswa dalam memahami aljabar, tidak perlu semua indikator pada\ud materi aljabar diujikan dalam tes. Mengetahui sangat pentingnya komponen utama dalam materi aljabar untuk mengukur kemampuan berfikir aljabar seorang siswa maka peneliti mencoba menganalisis kemampuan berfikir aljabar siswa kelas VII di SMPN 1 Krangkeng. Teknik pengumpulan data yang digunakan dalam penelitian ini adalah tes. Populasi dalam penelitian ini adalah Kelas VII yang berjumlah (160 siswa). Sampel diambil dari kelas VIIB cluster random sampling. Untuk uji coba dilakukan di kelas VIIA yang berjumlah 32. Dari hasil penelitian diperoleh hasil sebagai berikut: 1) Aljabar di SMP N 1 Krangkeng cukup baik hal ini ditunjukan dengan nilai rata-rata 75. 2) Indikator kemampuan berfikir aljabar secara mekanisme dan indikator Kemampuan terbesar yang dicapai oleh siswa kelas VII SMP Negeri 1 Krangkeng tahun ajaran 2012/2013 dalam memahami aljabar adalah pada pengertian koefisien, variabel, konstanta, faktor, suku sejenis adalah sebesar 89.58% dan kemampuan yang kurang dikuasai oleh siswa kelas VII SMP Negeri 1 Krangkeng tahun ajaran 2012/2013 dalam memahami aljabar adalah memahami invers adalah sebesar 85.94%. 3) Dari delapan indicator kemampuan berfikir aljabar ada tiga komponen yang dominan yaitu menggunakan diagram alur, pengertian koefisien variable konstanta, faktor suku sejenis, dan menyederhanakan operasi aljaba

Constant High Temperature Promotes Early Changes in Testis Development Associated with Sexual Maturation in Male Atlantic Salmon (Salmo salar L.) Post-Smolts

Sexual maturation of post-smolts is a concern for Atlantic salmon producers, and its occurrence is dependent upon factors such as water temperature and energy availability, among others. The present study was designed to investigate the effect of different temperatures and feeding regimes on testis development and local regulation of spermatogenesis in salmon post-smolts. A 3 × 2 factorial design was used, with three temperatures (8 °C, 12.5 °C, and 18 °C) and two feed regimes (100% and 67% ration). Salmon (1800 parr, initial mean weight 23.1 ± 7.2 g) were reared from 28 October 2018 to 30 May 2019 in a freshwater flow-through system under continuous light (LD24:0), except for a 5-week winter signal (LD12:12) introduced on 4 February 2019. Testis histology, transcription of follicle-stimulating hormone receptor (fshr) and luteinizing hormone receptor (lhr), and transcription of testis proteins involved in spermatogenesis regulation such as gonadal-soma-derived factors 1 (gsdf1) and 2 (gsdf2), anti-Müllerian hormone (amh), and insulin-like growth factor-3 (igf3), were analyzed. Results showed that high temperature alone (18 °C), irrespective of the feed regime, promoted early presence of type B spermatogonia and reduced transcript levels of the proliferation-inhibitory factor amh in males still considered immature, of groups 18–100% and 18–67% that later matured in high proportion (~100%). This effect was also present to some degree in the group 12.5–100% (40% maturation), and absent in 12.5–67%, 8–100%, and 8–67% (groups with little or no maturation). Later, at onset of rapid testis growth, high temperature was linked to a pronounced downregulation of amh and of the self-renewal factors gsdf1 and gsdf2, as well as to a pronounced upregulation of the proliferation-stimulating factor igf3. Overall, the present findings demonstrate that rearing salmon at high temperatures can stimulate an early activation of the brain–pituitary–gonad axis before actual onset of rapid testis growth, enhancing and accelerating the mechanisms that control initiation and progression of maturation, while the feed regime has a minor impact. This poses a challenge for current salmon aquaculture practices that use sustained high temperature to maximize growth, since these practices increase the risk of early post-smolt maturation.publishedVersio

Triploid Atlantic salmon and triploid Atlantic salmon × brown trout hybrids have better freshwater and early seawater growth than diploid counterparts

The use of reproductively sterile triploid salmonids would enhance the environmental sustainability of the aquaculture industry by preventing genetic exchange between escapees and wild conspecifics. To this end, we assessed smoltification and early seawater performance (241 days) following a yearling production cycle (i.e. spring smolts) in diploid and triploid female Atlantic salmon (Salmo salar) × male brown trout (Salmo trutta) hybrids compared to purebred diploid and triploid salmon. During freshwater rearing (n = 180/group), hybrids demonstrated a degree of bimodality in body size, significantly (p < 0.05) more so in diploid than triploid hybrids (11 and 37% in the lower mode, respectively) that was not seen in purebred salmon of either ploidy. This resulted in diploid hybrids being 66% smaller on average at sea transfer, whereas no hybridisation effect was seen in triploids, and both triploid groups were significantly heavier (16–43%) than diploid salmon. Irrespective of ploidy, lower mode hybrids grew poorly and showed low survival in seawater, suggesting they had failed to undergo smoltification. However, the upper mode diploid hybrids showed a similar Na+/K+-ATPase (NKA) enzyme activity surge during the spring as in diploid and triploid salmon, despite a higher ratio of the freshwater to seawater mRNA abundance of the NKA subunits (nkaα1a and nkaα1b) and a reduced plasma cortisol surge. At the end of the experimental period, both hybrids weighed significantly less than their salmon counterparts although the hybrid effect was again greater in diploids (71% smaller) than triploids (6% smaller). In addition, both triploid groups were on average heavier (15–22%) than diploid salmon. As such, both triploid Atlantic salmon and triploid hybrids can show enhanced growth performance from juveniles up to post-smolts compared to diploid salmon in an aquaculture setting

Triploid Atlantic salmon and triploid Atlantic salmon × brown trout hybrids have better freshwater and early seawater growth than diploid counterparts

The use of reproductively sterile triploid salmonids would enhance the environmental sustainability of the aquaculture industry by preventing genetic exchange between escapees and wild conspecifics. To this end, we assessed smoltification and early seawater performance (241 days) following a yearling production cycle (i.e. spring smolts) in diploid and triploid female Atlantic salmon (Salmo salar) × male brown trout (Salmo trutta) hybrids compared to purebred diploid and triploid salmon. During freshwater rearing (n = 180/group), hybrids demonstrated a degree of bimodality in body size, significantly (p < 0.05) more so in diploid than triploid hybrids (11 and 37% in the lower mode, respectively) that was not seen in purebred salmon of either ploidy. This resulted in diploid hybrids being 66% smaller on average at sea transfer, whereas no hybridisation effect was seen in triploids, and both triploid groups were significantly heavier (16–43%) than diploid salmon. Irrespective of ploidy, lower mode hybrids grew poorly and showed low survival in seawater, suggesting they had failed to undergo smoltification. However, the upper mode diploid hybrids showed a similar Na+/K+-ATPase (NKA) enzyme activity surge during the spring as in diploid and triploid salmon, despite a higher ratio of the freshwater to seawater mRNA abundance of the NKA subunits (nkaα1a and nkaα1b) and a reduced plasma cortisol surge. At the end of the experimental period, both hybrids weighed significantly less than their salmon counterparts although the hybrid effect was again greater in diploids (71% smaller) than triploids (6% smaller). In addition, both triploid groups were on average heavier (15–22%) than diploid salmon. As such, both triploid Atlantic salmon and triploid hybrids can show enhanced growth performance from juveniles up to post-smolts compared to diploid salmon in an aquaculture setting

Triploid Atlantic salmon and triploid Atlantic salmon × brown trout hybrids have better freshwater and early seawater growth than diploid counterparts

The use of reproductively sterile triploid salmonids would enhance the environmental sustainability of the aquaculture industry by preventing genetic exchange between escapees and wild conspecifics. To this end, we assessed smoltification and early seawater performance (241 days) following a yearling production cycle (i.e. spring smolts) in diploid and triploid female Atlantic salmon (Salmo salar) × male brown trout (Salmo trutta) hybrids compared to purebred diploid and triploid salmon. During freshwater rearing (n = 180/group), hybrids demonstrated a degree of bimodality in body size, significantly (p < 0.05) more so in diploid than triploid hybrids (11 and 37% in the lower mode, respectively) that was not seen in purebred salmon of either ploidy. This resulted in diploid hybrids being 66% smaller on average at sea transfer, whereas no hybridisation effect was seen in triploids, and both triploid groups were significantly heavier (16–43%) than diploid salmon. Irrespective of ploidy, lower mode hybrids grew poorly and showed low survival in seawater, suggesting they had failed to undergo smoltification. However, the upper mode diploid hybrids showed a similar Na+/K+-ATPase (NKA) enzyme activity surge during the spring as in diploid and triploid salmon, despite a higher ratio of the freshwater to seawater mRNA abundance of the NKA subunits (nkaα1a and nkaα1b) and a reduced plasma cortisol surge. At the end of the experimental period, both hybrids weighed significantly less than their salmon counterparts although the hybrid effect was again greater in diploids (71% smaller) than triploids (6% smaller). In addition, both triploid groups were on average heavier (15–22%) than diploid salmon. As such, both triploid Atlantic salmon and triploid hybrids can show enhanced growth performance from juveniles up to post-smolts compared to diploid salmon in an aquaculture setting

NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics

Xenarthrans—anteaters, sloths, and armadillos—have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, 10 anteaters, and 6 sloths. Our data set includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the southern United States, Mexico, and Caribbean countries at the northern portion of the Neotropics, to the austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n = 5,941), and Cyclopes sp. have the fewest (n = 240). The armadillo species with the most data is Dasypus novemcinctus (n = 11,588), and the fewest data are recorded for Calyptophractus retusus (n = 33). With regard to sloth species, Bradypus variegatus has the most records (n = 962), and Bradypus pygmaeus has the fewest (n = 12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other data sets of Neotropical Series that will become available very soon (i.e., Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans data set. Please cite this data paper when using its data in publications. We also request that researchers and teachers inform us of how they are using these data