Return Migration, Human Capital Accumulation and the Brain Drain

In this paper we present a model that explains migrations as decisions that respond to where human capital can be acquired more efficiently, and where the return to human capital is highest. The basic framework is a dynamic Roy model in which a worker possesses two distinct skills that can be augmented by learning by doing. There are different implicit prices, in different countries and different rates of skill accumulation. Our analysis contributes to the literature on the selection of immigrants and return migrants by offering a richer framework that may help to accommodate selection of emigrants and return migrants that are not immediately compatible with the one-dimensional skill model. Our analysis also has implications for the debate on brain drain and brain gain. In the two skills model presented here, return migration can lead to a mitigation of the brain drain, or even the creation of a "brain gain", where those who return bring the home country augmented local skills.Return migration, human capital accumulation, comparative advantage, brain drain

Histological Chages of Testis and Caput Epididymis in the Goat after Cannulation of the Rete Testis

雄ヤギ5頭を用い, 精巣網カテーテル装着手術後の精巣および精巣上体頭の組織構造を観察するとともに精巣静脈血中のテストステロン濃度を調べた。カテーテル装着手術後の精巣は, いずれも萎縮し, 正常な精子形成過程が観察される精細管は少なかった。また, ライディヒ細胞の形態や染色性には異常は認められなかった。一方, 精巣上体頭では, 精巣上体管が萎縮し, 主細胞の高さは無傷のものよりも有意に減少した。同様の組織構造の変化は, 精巣輸出管を切除した場合の精巣および精巣上体頭でも認められた。精巣静脈血中のテストステロン濃度は無傷の場合94.4ng/mlであり, カテーテル装着手術後では86.5∿342.8ng/mlであった。 / The testis and caput epididymis of the goat after cannulation of the rete testis or efferentiectomy were examined histologically. The concentration of testosterone in testicular venous blood collected from the same animals was also measured by radioimmunoassay. After cannulation, seminiferous tubules showed a sign of degeneration, although no morphological change of Leydig cells was observed. Epididymal ducts were severely atrophied and the height of principal epithelial cells was significantly decreased. A similar damage was observed in the testis and epididymis after efferentiectomy. When the efferent duct bundle had been incompletely ligated at cannulation, or rete testis catheter was kept in place until sampling time, damages in the testis were less severe. And in the former case the epididymis was impaired less severely. The concentration of testosterone in testicular venous blood collected from an intact animal was 94.4ng/ml, while that obtained after cannulation was 86.5-342.8ng/ml. These results suggest that degeneration of germ cells in seminiferous tubules observed after cannulation of the rete testis or efferentiectomy may be caused by stagnation of rete testicular fluid in the tubules, and that testosterone in the fluid plays important roles in the maintenance of morphology and function of the principal cells in the caput epididymis

PENGUJIAN VARIASI JUMLAH MATA PISAU PENGEPRAS TERHADAP KUALITAS PEMOTONGAN DAN PERTUMBUHAN ANAKAN TEBU

Pengeprasan tebu merupakan pemotongan sisa-sisa tunggul tebu setelah penebangan yang dilakukan pada posisi tepat atau lebih rendah dari permukaan tanah, setelah dilakukan pengeprasan dilapangan terdapat rata-rata persentase potongan utuh paling banyak didapat pada perlakuan dengan jumlah 12 mata pisau kepras sebesar 91,11%, dan terendah didapat pada perlakuan dengan jumlah 10 mata pisau sebesar 84,44%. Rata-rata persentase keprasan pecah yang paling tinggi terdapat pada P2 yaitu sebesar 13,33%, sedangkan yang terendah terdapat pada P3 yaitu sebesar 6,67%. Rata-rata keprasan pecah pada semua perlakuan sama yaitu sebesar 2.22

Different dosages effectiveness of Ovaprim on the maturation of freshwater lobster (Cherax quadricarinatus)

Freshwater lobsters have been developed as a commodity for consumption since 2003. The need for this commodity is increasing but production is still very low, so the price of freshwater lobsters is quite high and expensive. Therefore, it is necessary to carry out reproduction to carry out the seeding process for Freshwater Lobsters (LAT) using an injection technique in the form of the Ovaprim Hormone to accelerate the maturity of the LAT gonads. This study aims to examine the administration of different doses of the ovaprim hormone on the maturation of freshwater lobster broodstock. The research was conducted for 60 days. The method used was a Randomized Block Design (RAK) with 4 treatments and 3 replications. The treatments in this study were P0 (control), P1 (0,3 ml), P2 (0,5 ml) and P3 (0,7 ml). The parameters observed in this study were Gonad Maturity Index (IKG), Egg Diameter and Pleopode Fecundity. The results of the observations showed that giving different doses of ovaprim to the maturation of freshwater crayfish was not significantly different (P<0.05) to the Gonad Maturity Index IKG), Egg Diameter and Pleopode Fecundity but was significantly different to the P0 (control) treatment. The best treatment in this study was treatment P3 (0.5 ,l) because it had the highest performance between the other treatments.Keywords: egg diameter; fecundity; freshwater lobster; maturation; ovapri

Gonad maturity and gonadal somatic index of blue swimming crab Portunus pelagicus harvested from Spermonde Archipelago, South Sulawesi, Indonesia

Reproductive biology is one of the biological aspects that needed to formulate responsible management of blue swimming crab (BSC). The crab is one of the commercial fisheries commodities in South Sulawesi, Indonesia. Presently no information on the reproductive biology of this crab from Spermonde Archipelago, Sout Sulawesi. Therefore, the study aimed to analyze and compare gonad maturity stage(GMS)andgonadalsomaticindex(GSI)oftheBSCcaughtonthreeecosystemsnamelycoralreef,seagrass,andmangrovein Salemo Island, Spermonde Archipelago. GMS and GSI were analyzed descriptively for five months from March to July 2015. Results indicate there was a difference in GMS of the BSC caught in mangroves, seagrass, and coral reef. Generally, mangrove was dominated by immature BSC with GMS I and GMS II, while the BSC caught in the seagrass and coral reef BSC were dominantly mature and spawn GMS III, IV, and V. GSI BSC caught in mangrove ecosystem are smaller than GSI BSC caught in seagrass and coral reef ecosystems. Seagrass and coral reef ecosystems suitable for development no-take zone of the BSC

Diversitas Ikan Pada Perairan Tawar Kota Langsa

Inventarisasi sumber daya perairan dan keragamannya memegang peranan yang sangat penting untuk kelanjutan budidaya perairan sebagai sumber informasi genetik untuk domestikasi ikan. Penelitian ini dilakukan untuk mengetahui ikan-ikan jenis apa saja yang terdapat di perairan tawar Kota Langsa yang didominasi oleh rawa dan alur sawit dikarenakan banyaknya terdapat perkebunan sawit di daerah ini. Penelitian dilakukan melalui sampling survey menggunakan jaring insang dengan ukuran mata jaring 1 inci dan 1,5 inci dibeberapa stasiun. Hasil penelitian menunjukkan bahwa ikan yang mendominasi perairan Kota Langsa adalah sepat rawa, sedangkan dua jenis ikan lainnya yang terjaring alat sampling adalah ikan gabus pasir dan ikan betok. Sementara ikan yang potensial untuk didomestikasi dari ketiga jenis ikan tersebut adalah ikan betok karena memiliki nilai ekonomis yang cukup tinggi

Efektivitas Pembangunan Infrastruktur Perdesaan Melalui Program Dana Desa Kabupaten Pidie Jaya

Abstrak Pembangunan infrastruktur perdesaan yang efektif merupakan prasarana desa yang diharapkan oleh masyarakat desa untuk dapat meningkatkan taraf hidupnya, maka pembangunan infrastruktur yang efektif dan berkualitas melalui program dana desa menjadi ujung tombak dalam pembangunan desa. Penelitian ini menggunakan metode kombinasi dengan cara menggabungkan metode kuantitatif dan kualitatif. Penelitian ini berlokasi di Kabupaten Pidie Jaya dengan menganalisis data dari tahun 2019-2023. Hasil dari analisis adalah efektivitas pembangunan infrastruktur perdesaan melalui program dana desa ditinjau dari aspek waktu sebesar 75,63% dengan kategori Cukup Efektif, dan ditijau dari aspek biaya yaitu 98,82% dengan kategori Efektif, sedangkan tinggi kualitas infrastruktur pada pembangunannya ditinjau dari aspek kualitas mutu beton dengan hasil berkualitas Baik, ditinjau dari aspek arsitektur/estetika dengan hasil berkualitas Baik, dan tinjau dari aspek dimensi proyek dengan hasil juga berkualitas Baik sehingga dapat disimpulkan bahwa pembangunan infrastruktur perdesaan melalui program dana desa di Kabupaten Pidie Jaya sudah Efektif dan berkualitas Baik. Kata kunci: Efektivitas, Kualitas, Pembangunan infarstruktur, Dana desa. Abstract Effective rural infrastructure development is a village infrastructure that is expected by rural communities to be able to improve their standard of living. Therefore, effective and quality infrastructure development through the village fund program is the spearhead in village development. This study uses a combination method by combining quantitative and qualitative methods. This study is located in Pidie Jaya Regency by analyzing data from 2019-2023. The results of the analysis in this study are the effectiveness of rural infrastructure development through the village fund program in terms of time aspect of 75.63% with the category of Quite Effective, and in terms of cost aspect of 98.82% with the category Effective. While the high quality of infrastructure in its development is reviewed from the aspect of concrete quality with good quality results, reviewed from the aspect of architecture/aesthetics with good quality results, and reviewed from the aspect of project dimensions with results also of Good quality so it can be concluded that rural infrastructure development through the village fund program in Pidie Jaya Regency is Effective and of Good quality Keywords: Effectiveness, Quality, Infrastructure development, Village funds