Effects of Photoradiation on the Growth and Potassium, Calcium, and Magnesium Uptake of Lettuce Cultivated by Hydroponics

Photoradiation plays a major role in plant growth processes, especially photosynthesis and nutrient uptake. Light intensity and photoperiod affect temperature and caused more transpiration in plants, which influences nutrient uptake. This study aimed to examine the effects of photoradiation on the growth and K, Ca, and Mg uptake of lettuce (Lactuca sativa L.). Lettuce was hydroponically grown in a walk-in growth chamber, and the experiment was performed using eight treatments with eight replications. A combination of eight fluorescent lamps was used to provide a photon flux density of 128±20 umole m-2 s-1 for 15/15 minutes, 45/15 minutes, 345/15+15/15 minutes of black UV, and 345/15+15/45 minutes of black UV of light/dark periods. A combination of ten fluorescent lamps was used to provide a photon flux density of 194±28 umole m-2 s-1 for 30/30 minutes, 15/15 minutes, and 45/15 minutes of light/dark periods and 24 hours of light period. Continuous illumination with higher light intensity gave the greatest shoot fresh weight, plant height and number of leaves. Whereas a shorter photoperiod and lower light intensity gave the lowest shoot fresh weight. Shortened UV light radiation gave better result in lettuce growth performance such as shoot fresh weight, plant height and number of leaves. UV light also damaged the lettuce leaves. The leaves turned brown (brown spot) at the tip of the old leaves. Molar concentrations of K, Ca and Mg in the lettuce leaves were in the order of K > Ca > Mg for all of the treatments. The steep gradient and highest K accumulation at bottom leaves were found at lower light intensity and short photoperiod (15/15 minutes of light/dark). Extended photoperiod improved K and Ca movement and reduced K and Ca accumulation in the bottom leaves. High K in the leaves reduced Ca uptake. Continuous illumination with higher light intensity resulted in the lowest concentrations of K, Ca and Mg. The mole ratio of K/Ca decreased from the top to bottom leaves, whereas the mole ratio of K/Mg tended to be stable except in the treatment with lower light intensity and short photoperoid. The best growth performance was found in the treatment with consistent K/Ca ratio.

Effect of light intensities on reproductive performance, nursing behaviour and preference of rabbit does

The aim of the experiment was to compare the reproductive performance and nursing behaviour of rabbit does reared under 2 different light intensities and observe the preference of does among cages with different light intensities. Female rabbits were randomly housed in 2 identical rooms, under the same housing conditions in wire-net cages. The 2 rooms only differed in the light intensity; group L: 150-200 lux (n=54 does, 230 inseminations), group D: 10-20 lux (n=54 does, 232 inseminations). Reproduction data from the first 5 consecutive reproductive cycles were evaluated. Nursing behaviour of the does (n = 24) was observed at the 2nd or 4th lactation. The preference of does (n=8) among 4 cages with different light intensities (10, 35, 75 or 155 lux) as examined. There were 6-7% difference between the 2 groups in the number of kits born in total and those born alive (born total: 11.25 vs. 10.59 kits, P<0.1; liveborn: 10.75 vs. 10.00 kits, P<0.05; in groups L and D, respectively). Suckling mortality was nearly 2% higher in group D (L: 8.1, D: 10.0%; P<0.1), and in consequence the litter size of this group at 35 d of age was lower than that of the L rabbits (L: 8.75, D: 8.45 kits; P<0.05). The light intensity did not affect litter and individual weights at 35 d of age. The average numbers of daily nursing events (L: 1.23/d, D: 1.32/d), the length (L: 208±49, D: 213±43 s) and the daily distribution of nursing events were not affected by high light intensity. During the light period of the day, the darkest cage (10 lux) was the most preferred by the does (44.0, 18.6, 17.9 and 19.5% in 10, 35, 75 and 155 lux cages, respectively; P<0.001). The lower light intensity had no unambiguously unfavourable effect on the reproductive performance and nursing behaviour of the does. Based on the preference test, a lower light intensity may be advantageous from the point of view of animal welfare.

Implementasi Algoritma Kunang-Kunang Untuk Penjadwalan Mata Kuliah di Universitas Ma Chung

Course scheduling is considered as a complex matter because the generated schedule must guarantee that there are no clashes of classes, lecturers, and students’ schedules. At Ma Chung University, course scheduling is still accomplished manually. Due to the limited number of rooms and lecturers r, resource sharing system is applied. This causes complication in manual scheduling. Firefly algorithm is implemented in this application to schedule the course automatically. A schedule solution is represented as a firefly. Firefly with lower light intensity will move toward firefly with higher light intensity, so that a better solution is found. Based on a scheduling test, the best light intensity value of firefly is reached when firefly algorithm’s parameters, β0 and γ, are given 1 and 10 with light intensity value of 0,0003831. Keywords: course, firefly algorithm, scheduling  Abstrak. Penjadwalan mata kuliah merupakan hal yang kompleks karena jadwal yang dihasilkan tidak hanya menjamin jadwal pertemuan semua kelas dan dosen tidak bentrok, tetapi juga menjamin jadwal pertemuan semua mahasiswa tidak bentrok. Penjadwalan mata kuliah di Universitas Ma Chung masih dilakukan secara manual. Karena jumlah kelas dan dosen yang dimiliki terbatas, maka diterapkan sistem resource sharing. Sistem resource sharing ini membuat proses penjadwalan yang dilakukan secara manual menjadi lebih rumit. Algoritma yang digunakan untuk penjadwalan mata kuliah pada aplikasi ini adalah algoritma kunang-kunang. Sebuah solusi jadwal mata kuliah dalam algoritma kunang-kunang direpresentasikan sebagai seekor kunang-kunang. Kunang-kunang dengan intensitas cahaya yang lebih rendah akan bergerak menuju kunang-kunang yang lebih terang sehingga mampu didapatkan solusi jadwal mata kuliah yang lebih baik. Berdasarkan hasil uji coba, nilai intensitas cahaya terbaik didapatkan ketika parameter algoritma kunang-kunang, β0 dimasukkan 1 dan γ dimasukkan 10 hingga didapatkan intensitas sebesar 0,0003831. Kata Kunci: algoritma kunang-kunang, mata kuliah, penjadwalan

ACCUMULATION AND METABOLISM OF CARBOHYDRATES IN MARIGOLD SEEDLINGS

Marigold seedlings, 3 weeks old, were grown in natural light growth chambers at 3 day/night temperature regimes, 8°N/16°D, 13°N/20°D and 18°N/24°D, in a factorial combination with ambient and 1000-1500 ppm CO2. Seedlings were harvested at regular intervals during a 24 hr period and were analyzed for soluble sugars (reducing sugars and sucrose) and starch. Neither temperature nor CO2 concentration affected the accumulation of soluble sugars or starch during the day or night. The soluble sugar concentration ranged from 3% of dry weight at sunrise to 6% at mid-day; the concentration changed little during the night. Light intensity was different during replications of the experiment. Increased light intensity appeared to cause a slight increase in the soluble sugars maintained by the seedling during the day. Accumulated starch increased 6% to 8% from sunrise to late afternoon. Preliminary results indicate that light intensity greatly affected the concentration of starch. On the higher light intensity day, starch accumulated to a maximum of 18% of dry weight; whereas on the lower light intensity day the maximum concentration was 10%. During the night following the lower light intensity day, the starch concentration decreased to approximately 3% by the end of the night; following a brighter day the starch content was 13% at the end of the night.