Director Characteristics and Firm Performance

The traditional methodology examining optimal boards relates a simple board variable (e.g. independence or board demography) to firm performance, however, ig- noring other board characteristics. This paper investigates how the education and business experience of directors affect firm performance. The sample consists of 1,574 directorships from 224 listed firms in Switzerland. Using OLS and including control variables, the results show that graduates of minor Swiss universities are negatively related to Tobin’s Q, and industrial knowledge and Tobin’s Q are nega- tively correlated if the firm has more divisions. In addition, director fixed effects (or unobserved characteristics) are significant, but improve the explanatory power of the models only by 5 percent

The population biology of wrinklegrass (Ischaemum rugosum Salisb.) -Seed and seedling dynamics [Biologi populasi rumput colok cina (Ischaemum rugosum Salisb.) -Dinamik biji benih dan anak benih]

Abstrak Penyelarasan populasi, satu proses yang menetapkan ketentuan individu, wujud di dalam sesuatu persekitaran. Kerap kali tapisan persekitaran yang menyelaras silih ganti populasi individu di dalam sesuatu populasi sama ada bergantung pada kepadatan atau masa melalui fasa-fasa pengeluaran biji benih, serta kemunculan dan pertapakan anak benih. Kajian telah dijalankan untuk menilai dinamik populasi biji benih dan anak benih rumput colok cina (Ischaemum rugosum Salisb.) dari segi kepadatan dan masa. Daya pengeluaran biji benih generasi pertama dan kedua bagi populasi sintetik rumput colok cina tidak ketara berbeza berbanding dengan populasi asal induk, meskipun hubungan purata hujan biji benih sepokok adalah berlawanan dengan peningkatan selari kepadatan taburan atau hujan biji benih. Satu genet rumput colok cina yang tumbuh sendirian tanpa jiran mengeluarkan sehingga 6 000 biji benih bagi satu kitaran hidup selama 4 bulan atau 18 000 biji benih setahun. Nilai selari bagi kadar tabur pada kepadatan 1 000-6 000 biji benih/m di dalam generasi pertama populasi sintetik adalah di dalam lingkungan 48-62 biji benih sepokok. Daya pengeluaran biji benih rumput colok cina berkurangan sebanyak 50% bagi dua kali peningkatan selari kepadatan hujan biji benih. Kejayaan penjelmaan anak benih daripada hujan biji benih adalah masing-masing pada kadar 85% dan 90% bagi generasi pertama dan kedua. Penyelarasan populasi melalui mortaliti anak benih yang bergantung pada kepadatan atau pengurangan sendirian populasi, dan pengurangan populasi dari segi masa wujud di kalangan generasi pertama dan kedua populasi sintetik anak benih. Kadar kejayaan bagi anak-anak benih yang muncul bertapak menjadi dewasa ialah 80.8% dan 22.8% masing-masing bagi populasi generasi pertama dan kedua. Purata jumlah berat biji benih bagi dua generasi berturut-turut rumput colok cina adalah seiringan dengan Hukum Hasil Akhir Konstan Kira. Abstract Population regulation, an important process determining the fate of individuals, prevails in an environment. Quite often the environmental sieves regulating the population fluxes of individuals in a population are either density-or timemediated through the phases of seed production, seedling emergence and The population biology of wrinklegrass establishment. Studies were conducted to assess the density-and time-mediated dynamics of synthetic seed and seedling populations of wrinklegrass (Ischaemum rugosum Salisb.). Seed production capacity of the first, and second generation synthetic populations of wrinklegrass did not vary significantly with the initial parental population, although the mean seed rain per plant was inversely related to the corresponding increase in sowing or seed rain density. A single genet of wrinklegrass grown devoid of neighbours, produced up to 6 000 seeds within a growth cycle of 4 months or 18 000 seeds per year. The parallel figures for the respective sowing densities of 1 000-6 000 seeds/m 2 in the first generation synthetic population ranged from 48-62 seeds/plant. Invariably, the seed production capacity of wrinklegrass was reduced by 50% with twice the corresponding increase in seed rain density. The respective success rate of seeds from the seed rain emerging as seedlings were 85% and 90% in the first and second generation populations. Population regulation via density-dependent mortality or self-thinning, and time-mediated decrease prevailed among emerged seedlings in the first and second generation synthetic populations. The success rates of emerged seedlings becoming established plants in the first and second generation populations were 80.8% and 22.8%. The mean total seed weights of two successive generations of wrinklegrass were in line with the Kira's Law of Constant Final Yields

Analysis of Four Delineation Methods to Identify Potential Management Zones in a Commercial Potato Field in Eastern Canada

Management zones (MZs) are delineated areas within an agricultural field with relatively homogenous soil properties, and therefore similar crop fertility requirements. Consequently, such MZs can often be used for site-specific management of crop production inputs. This study evaluated the effectiveness of four classification methods for delineating MZs in an 8-ha commercial potato field located in Prince Edward Island, Canada. The apparent electrical conductivity (ECa) at two depths from a commercial Veris sensor were used to delineate MZs using three classification methods without spatial constraints (i.e., fuzzy k-means, ISODATA and hierarchical) and one with spatial constraints (i.e., spatial segmentation method). Soil samples (0.0–0.15 m depth) from 104 sampling points was used to measure soil physical and chemical properties and their spatial variation in the field were used as reference data to evaluate four delineation methods. Significant Pearson correlations between ECa and soil properties were obtained (0.22 < r < 0.85). The variance reduction indicated that two to three MZs were optimal for representing the field’s spatial variability of soil properties. For two MZs, most soil physical and chemical properties differed significantly between MZs for all four delineation methods. For three MZs, there was greater discrimination among MZs for several soil properties for the spatial segmentation-based method compared with other delineation methods. Moreover, consideration of the spatial coordinates of the data improved the delineation of MZs and thereby increased the number of significant differences among MZs for individual soil properties. Therefore, the spatial segmentation method had the greatest efficiency in delineation of MZs from statistical and agronomic perspectives