1,720,965 research outputs found
KESUBURAN TANAH DAN LAJU FOTOSINTESIS TANAMAN KELAPA SAWIT YANG MENUNJUKKAN GEJALA WHITE STRIPE PADA LAHAN GAMBUT DI LABUHAN BATU
Full text linkWhite stripe is the loss of green pigment with elongated shape on left and right side of the mid-rib. White stripe is often associated with an imbalance in the N/K nutrient ratio in oil palm. This study aims to determine soil fertility, growth, and photosynthesis rate of oil palm that expressing white stripe symptoms on Fluvaquentic Haplosaprists in Labuhan Batu, North Sumatra. This research was conducted by observing the ecophysiology of 3 plant conditions consisting of a) healthy oil palms, b) oil palms expressing white stripe symptoms, and c) oil palms expressing Boron deficiency symptoms. The results showed that peat soil at the research site has good fertility status. Soil fertility of all treatments are similar except its available nutrients, where the oil palms expressing white stripe symptoms have average P available, K, Ca, Na, and Mg exchanged lower than healthy oil palms as well as oil palms expressing Boron deficiency symptoms. Oil palms expressing white stripe symptoms have low leaf N/K rasio (2.19), and have no relation with Boron deficiency, with unsignificant leaf area indeks (LAI) compared to other treatments. Low chlorophyll content of oil palms expressing white stripe and Boron deficiency symptoms have affected to low rate of photosynthetic rate and, If not corrected immediately, white stripe and also boron deficiency will affect to oil palm growth and productivity.White stripe merupakan hilangnya pigmen hijau dengan bentuk memanjang pada bagian sisi kiri dan kanan dekat lidi pada anak daun. White stripe sering dikaitkan dengan ketidakseimbangan rasio hara N/K pada tanaman kelapa sawit. Penelitian ini bertujuan untuk mengetahui kesuburan tanah, pertumbuhan tanaman, dan laju fotosintesis tanaman kelapa sawit yang menunjukkan gejala white stripe pada lahan gambut Fluvaquentic Haplosaprists di Labuhan Batu. Penelitian ini dilakukan dengan cara mengamati ekofisiologi dari 3 kondisi tanaman yang terdiri dari: a) tanaman sehat tanpa gejala white stripe maupun gejala defisiensi Boron, b) tanaman dengan gejala white stripe, dan c) tanaman dengan gejala defisiensi Boron. Hasil penelitian menunjukkan bahwa tanah pada areal percobaan memiliki status kesuburan yang cukup baik. Kesuburan tanah dari 3 kondisi tanaman hampir tidak berbeda kecuali kadar hara tersedia, dimana tanaman dengan gejala white stripe memiliki rerata P tersedia, serta K, Ca, Na, dan Mg dapat ditukar yang lebih rendah dibanding tanaman sehat maupun tanaman yang menunjukkan gejala defisiensi Boron. Tanaman dengan gejala white stripe memiliki rasio N/K daun yang rendah (2,19), dan tidak menunjukkan kaitan dengan terjadinya defisiensi Boron, dengan indeks luas daun (ILD) yang tidak berbeda nyata dibanding perlakuan lainnya. Kandungan klorofil yang rendah pada daun tanaman dengan gejala white stripe maupun defisiensi Boron mengakibatkan rendahnya laju fotosintesis dan ILD. Jika gejala white stripe maupun defisiensi Boron ini tidak segera diatasi, maka hal ini akan berakibat menurunnya pertumbuhan dan produktivitas tanaman kelapa sawit
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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
Technique to Estimate Oil Palm Transpiration Using Heat Ratio Method
Full text linkSalah satu metode yang digunakan untuk menentukan kebutuhan air tanaman adalah dengan menghitung transpirasi tanaman. Metode Heat Ratio Method (HRM) adalah metode yang dapat mengukur transpirasi langsung di lapangan dengan mengukur laju aliran sap di dalam tanaman. Tujuan dari penelitian ini adalah untuk mengestimasikan kebutuhan air tanaman kelapa sawit berdasarkan pengukuran transpirasi tanaman kelapa sawit dengan HRM. Penelitian dilakukan pada tanaman kelapa sawit umur 5 tahun yang memiliki 48 pelepah di Medan, Sumatera Utara. Sebanyak 6 alat Sap Flow Meter dipasang pada pelepah no. 1, 9, 17, 25, 33, dan 41. Hasil penelitian menunjukkan bahwa laju aliran sap pada tiga pelepah teratas (no. 1, 9, dan 17) lebih tinggi dibandingkan tiga pelepah di bawahnya. Lebih lanjut, transpirasi tertinggi terjadi pada pelepah no. 1 yaitu sebesar 0,890 liter/hari, sedangkan transpirasi terendah teramati pada pelepah no. 41 yaitu 0,510 liter/hari. Laju transpirasi semakin menurun pada pelepah yang lebih bawah posisinya. Rerata transpirasi harian adalah sebesar 31,933 liter/hari/tanaman atau setara dengan 0,457 mm/hari/tanaman, dengan asumsi bahwa masing-masing pelepah yang dijadikan sampel mewakili pelepah pada tingkatan pelepah yang sama.The estimation of plant transpiration is one of many methods to determine plant water requirements. Heat Ratio Method (HRM) is a method that can estimate transpiration directly under field conditions by measuring sap flow rate. This research was conducted to estimate oil palm water requirements based on transpiration estimation using HRM. The study was located in Medan, North Sumatra, and was employed five years old palm with 48 fronds. A total of six Sap Flow Meter (SFM) were installed on the fronds no. 1, 9, 17, 25, 33, and 41. The results showed that the sap flow rate of the top three fronds (no. 1, 9, and 17) was higher than the lower fronds. The transpiration rate was decreased at the lower fronds position. Furthermore, the highest transpiration occurred in frond no. 1, 0.890 liters/day, while the lowest was observed in frond no. 41 i.e. 0.510 liters/day. Assuming that each frond sampled represents fronds at the same level, the average daily transpiration was 31.933 liters/day/palm or equivalent to 0.457 mm/day/palm
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
OPTIMALISASI PERTUMBUHAN TANAMAN KELAPA SAWIT DI TANAH SPODOSOL
Full text linkSemakin terbatasnya lahan yang optimal, membuat pengembangan kelapa sawit saat ini diarahkan ke lahan marginal. Lahan dengan jenis tanah spodosol merupakan salah satu lahan marginal yang telah dimanfaatkan untuk pengembangan kelapa sawit. Selain memiliki lapisan spodik, faktor pembatas lain dari tanah spodosol ialah memiliki tekstur kasar (terbentuk dari bahan pasir atau pasir berlempung) dengan iklim dingin dan tropika basah serta bersifat masam. Akibatnya, tanah tersebut memiliki kemampuan yang rendah dalam menahan air dan pencucian hara akan menjadi lebih tinggi. Pengolahan yang tepat sangat diperlukan agar kelapa sawit yang ditanam pada tanah spodosol dapat tumbuh dengan optimal. Beberapa cara yang dapat dilakukan adalah dengan mengidentifikasi tanah spodosol dan tingkat kedalaman lapisan spodik, memperbaiki media pertumbuhan tanaman, memperbaiki iklim mikro dan pemupukan yang tepat
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