Judul: Analysis of portfolio optimization with and without shortselling based on diagonal model: evidence from indonesian stock market
Abstrak: Markowitz (1952, 1959) and Roy (1952) proposed portfolio theory which narrate that risk of a portfolio is the variance of individual securities and covariances among those securities comprising the portfolio. The objectives of this research is to construct an optimized portfolio using Sharpe's diagonal model with and without short selling respectively, and to analyze the performance of less diversified optimal portfolios by investing in a single industry versus well diversified portfolio by investing across all industries. Finally to analysis the statistical properties of the estimates of diagonal model. Markowitz mean-variance portfolio optimization theory is implemented for all stocks listed in 9 sectors of Indonesian stock market during 2007-2011. However our model used 269 stocks which are not contradicting to the basic assumptions of the diagonal model. Diagonal model used in this research is a linear model and data used are time series secondary data. Firstly 9 optimal portfolios are computed for individual sectors with the assumption that short selling not permitted and then computation is done with assumption that short selling is permitted. Similarly 2 optimal portfolios are computed consisting of all stocks with assumptions mentioned above. Results showed that both well diversified short and long portfolios provide higher returns at a specified risk level compare to portfolios consist of individual sectors stocks. Largest weight in short portfolio is from infrastructure, utilities and transportation sector equaling 17.2 percent. Largest weight in long only portfolio are from trade, investment and services sector equaling 23.2 percent. The more diversified and larger portfolios provide better tangency portfolio. All stocks short and long portfolios performed better than any other individual sector portfolio. Standard error for and residual standard error for other portfolios are large compare to individual stocks indicating risk was not diversified away. Least square parameters estimates were not quite promising such as value of portfolio beta happened to be less than individual stocks as well as value of its coefficient of determination shows most of the systematic risk could not get eliminated as low values of R2 for portfolios shows that most of the variance in stock return as well as in portfolio return is not explained by market variance therefore unsystematic risk could not get eliminated despite of forming a portfolio encompassing all equities listed in Indonesian Stock Exchange as suggested by results of regression analysis.
Keyword: Diagonal Model, Diversification, Portfolio Optimization, Short Sales

Judul: Sectoral Approach Optimal Stock Portfolio Formation in  Indonesia Stock Exchange
Abstrak: Investasi tidak akan lepas dari unsur risiko. Terdapat faktor-faktor yang mempengaruhi perubahan harga dan return saham sehingga timbulnya perbedaan antara apa yang diharapkan dan apa yang sebenarnya terjadi. Pendekatan sektoral dalam pembentukan portofolio dibentuk untuk dapat meminimalisir risiko dengan melakukan penyebaran risiko pada sekuritas yang memiliki karakteristik berbeda. Tujuan dari penelitian ini adalah 1) menganalisis kombinasi portofolio pembentuk portofolio optimal saham sektoral 2) menganalisis komposisi portofolio pembentuk portofolio optimal saham sektoral 3) menganalisis kinerja portofolio yang dibentuk. Teknik pengambilan sampel yang digunakan adalah purposive sampling. Alat analisis yang digunakan adalah Model Indeks Tunggal dengan menggunakan Microsoft excel. Hasil penelitian ini adalah portofolio optimum yang dibentuk berisi 28 saham-saham yang mewakili sembilan sektor yang ada di BEI. Tingkat pengembalian dan risiko yang diperoleh dari portofolio adalah 41.52% per tahun dan 28.08% per tahun. Sementara itu perhitungan sharpe ratio untuk mengukur kinerja portofolio adalah sebesar 1.2372.
Keyword: Bogor Agricultural University, Institut Pertanian Bogor, IPB, Optimal portfolio, Portfolio, Sectoral, Single index model, Investment, Stock return, Performance, Sharpe ratio, BEL

Judul: Definisi Kalsium Dan Fosfor Pada Sapi
Abstrak: Kalsium dan fosfor mempunyai peranan penting dalam beberapa proses faali tubuh. Fungsi utama kalsium adalah mengatur iri tabilitas neuromuskuler, kontraksi otot, pembekuan darah, kofaktor beberapa sistim enzim dan sebagai komponen penting dalam pembentukan tulang (Rechcigl, 1978). Fosfor adalah komponen utama ikatan energi tinggi yaitu ATP (Adenosin Tri Phosphate), merupakan komponen nukleoprotein, mengatur pH isi rumen dan sebagai sumber multiplikasi flora dan fauna rumen (Payne, 1977).
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