1,720,959 research outputs found
Potensi Ekspresi Biomarker Pada Ikan Gambusia (Gambusia Affinis) Yang Terpapar Logam Berat (Studi Kasus Sungai Wangi Dan Kadmium)
Get PDFKondisi lingkungan disekitar aliran sungai Wangi apabila dilihat dari
kondisi eksistingnya sangat memprihatinkan dengan banyaknya sampah yang
terdapat di sepanjang aliran. Baik dari sampah pemukiman maupun sampah
pertanian, sedangkan dari industi kebanyakan berupa limbah cairan. Hasil
identifikasi sumber pencemar dibagi menjadi 3 (tiga) area kajian yaitu area kajian
I (limbah pabrik/industri), area kajian II (limbah pemukiman) dan area kajian III
(limbah pertanian). hasil analisis data dengan menggunakan metode pollution
index (PI), jumlah indeks pencemaran rata-rata (PIrata-rata) pada sungai Wangi =
5,503 yang berarti kondisi sungai Wangi termasuk pada klasifikasi “cemar
sedang”.
Salah satu biota sebagai biomonitoring di aliran sungai Wangi adalah Ikan
Gambusia (Gambusia affinis). Ikan gambusia mampu bertahan hidup dan
berkembang biak pada lingkungan yang tercemar limbah. Ikan Gambusia
dikelompokkan dalam spesies invasive asing dengan ciri-ciri memiliki
kemampuan adaptasi yang tinggi terhadap perubahan lingkungan dan mampu
berkembang biak dengan cepat. Dalam mengamati efek yang terjadi, khususnya
cemaran logam berat cadmium pada ikan gambusia, perlu dilakukan
pengamatan toksisitas kadmium di laboratorium.
Nilai toksisitas letal (LC50-96 jam) Cd2+ pada ikan gambusia (Gambusia
affinis), yaitu sebesar 0,03±0,009 mg/L yang dapat dikategorikan kedalam
golongan dengan daya racun yang sedang (medium toxic); Paparan logam berat
cadmium menyebabkan meningkatnya aktivitas protease pada ikan gambusia
0,2-0,3 mmol/ml/menit; Pengamatan pada histopatologi memperlihatkan adanya
perubahan hyperplasia tulang rawan hyalin, proliferasi sel mukus, hipertropi sel
klorid, hyperplasia lamella sekunder dan fusi lamella sekunder; dan paparan akut
Gambusia affinis Cd2+ dapat menyebabkan perubahan histopathology organisme.
Cd2+ (bahkan pada konsentrasi lingkungan) mungkin memiliki dampak negatif
pada beberapa proses biokimia yang terhubung dengan produksi spesies
oksigen reaktif dan radikal bebas dalam organisme ikan.
Menurut hasil pemeriksaan dan pemindaian secara scanning elektron
mikroskopi, efek paparan kadmium pada luas permukaan CC dan kepadatannya
pada gambusia muda dengan hasil terdapat kerenggangan antara luas
permukaan dan kepadatan CC; Selain itu ditemukan hasil bahwa kadmium pada
sitoskeleton insang gambusia, dan terutama pada filamen aktin mengalami
perubahan morfologi dengan adanya penyerapan dari paparan kadmium; dan
Paparan terhadap Kadmium menyebabkan stres oksidatif pada insang ikan
Gambusia melalui peningkatan enzim SOD, CAT, MDA, GPx, GSH dan H2O2.
Mekanisme penyerapan kadmium memasuki ekosistem perairan melalui
aktivitas antropogenik dan biotranspormasi yang berlangsung di insang.
Mekanisme penyerapan terjadi secara homeostasis dan mengganggu
metabolisme ion lainnya dengan menghasilkan hypocalcaemia dan
hiperglikemia. Ikan Gambusia mampu mengakumulasi dan menganalisa dampak
x
paparan kadmium pada insang di sitoskeleton, chloride sel dan macropinositosis.
Ikan menggunakan insang sebagai organ utama dalam pernapasan. Proses
pernapasan berlangsung dalam insang melalui osmosis dan difusi. Organ insang
memiliki kemampuan bioavailabilitas terhadap kondisi lingkungan. Ion dan logam
berat terfiltrasi dalam organ insang. Sehingga insang juga mampu
mengakumulasi logam berat dan ion yang masuk dalam tubuh. Akumulasi logam
berat cadmium dalam tubuh ikan terjadi pada organ insang, hati dan ginjal.
Pendeteksian akumulasi cadmium dapat dilakukan dengan biomarker
metallotionein (MT). Proses penyerapan cadmium terjadi pada protein dalam
organ insang. Ekspresi MT menggambarkan tingkat serapan cadmium dan
instrument diagnostic pada ika
KONDISI TOTAL LEUKOSIT DAN PROTEIN PLASMA IKAN KOI (Cyprinus carpio Koi) PASCA PERENDAMAN EKSTRAK GRACILARIA VERRUCOSA YANG TERINFEKSI BAKTERI Aeromonas salmonicida
Get PDFThe study was conducted to determine total leucocyte and plasma protein of infected koi (Cyprinus carpio) after immersion in the extract of Gracillaria verrucosa. The experimental design of this research was Completely Randomized Design. Different doses of extract were used five treatments and three replicates. Data was analyzed by using ANOVA (one-way) there were significant different of total leucocyte. Total protein plasma at treatments of fish infected, showed protein of ben thinner. Doses immersion treatments at 19 ppm get significant effects of humoral and celluler system the infected of koi fish.Penelitian dilakukan untuk mengetahui kondisi total leukosit dan protein plasma ikan Koi (Cyprinus carpio) setelah perendaman ekstrak Gracilaria verrucosa. Rancangan penelitian ini menggunakan metode eksperimental dengan Rancangan Acak Lengkap, 5 perlakuan dan 3 kali ulangan.Hasil penelitian berdasarkan uji ANOVA menunjukkan bahwa terdapat perbedaan yang nyata pada total leukosit. Total protein plasma pada ikan perlakuan yang terinfeksi terlihat pita-pita protein yang semakin tipis. Perlakuan dosis perendaman 19 ppm memberikan pengaruh nyata pada sistem humoral dan seluler ikan koi pasca infeksi
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
