Effects of plant distribution on the foraging behavior of pollinators

Understanding floral constancy is a vital tool used to establish foraging behavior among pollinators in urban and natural landscapes. Floral constancy is defined as the tendency of a pollinator to exclusively visit a specific floral species. Pollinators that show higher levels of floral constancy are more likely to transfer conspecific pollen. On the other hand, lower levels of floral constancy are associated with pollinators who transfer heterospecific pollen. We conducted two studies, the first aimed to find the effects of urbanization on plant-pollinator interactions. From our research, we were able to uncover a pattern that showed pollinators to carry a higher proportion of conspecific pollen than heterospecific pollen in urban sites as opposed to natural sites. However, the driving force of this pattern is unknown. Therefore, in our second study, we speculated that the distribution of plants may be responsible for increased conspecific pollen proportions in urban areas. We posed the following questions; Are plants more clumped in urban or natural areas? If so, how does that affect species foraging behavior? We hypothesize that based on the Optimal Foraging Theory, the idea that animals maximize energy input while minimizing energy expenditure, we would expect plants to be more clumped in urban areas than in natural areas. We anticipate that if our results support the hypothesis, we can assume that pollinators are foraging between closely clumped plant species. However, if our results do not align with our hypothesis, further investigation is necessary to identify the driving force of this pattern

Automatic Balancing for Satellite Simulators with Mixed Mechanical and Magnetic Actuation

Dynamic spacecraft simulators are becoming a widespread tool to enable effective on-ground verification of the attitude determination and control subsystem (ADCS). In such facilities, the on-orbit rotational dynamics shall be simulated, thereby requiring minimization of the external torques acting on the satellite mock-up. Gravity torque is often the largest among the disturbances, and an automatic procedure for balancing is usually foreseen in such facilities as it is significantly faster and more accurate than manual methods. In this note, we present an automatic balancing technique which combines mechanical and magnetic actuation by the joint use of sliding masses and magnetorquers. A feedback control is employed for in-plane balancing in which the proportional and integral actions are provided by moving the masses, while the derivative action is provided by the magnetorquers. Compared to an earlier implementation by the authors relying on shifting masses only, the novel approach is shown to reduce the in-plane unbalance by an additional 45% on average

Pengaruh Metode Pembelajaran Mind Map Terhadap Hasil Belajar Siswa

Rendahnya hasil belajar siswa dapat dikarenakan adanya beberapa faktor seperti proses pembelajaran yang berlangsung serta pemilihan metode pembelajaran. Rendahnya tingkat prestasi hasil belajar siswa juga dipengaruhi oleh siswa yang merasa bosan dalam menerima materi dan tergolong pasif di kelas. Upaya meningkatkan hasil belajar siswa ini dengan menerapkan metode pembelajaran mind map. Tujuannya adalah mengukur pengaruh metode pembelajaran mind map pada mata pelajaran komputer dan jaringan dasar terhadap hasil belajar siswa. Metode yang digunakan adalah kuantitatif dengan Quasi Experimental. Hasil pengujian hipotesis menggunakan uji-t dengan separated varian, menunjukkan bahwa pada taraf signifikan 0.05 dengan diperoleh Thitung 7.65 > Ttabel 1.672, maka H0 ditolak dan H1 diterima. Hal ini menunjukkan bahwa terdapat pengaruh penggunaan metode pembelajaran mind map terhadap hasil belajar dengan hasil aspek afektif dari kedua kelas dikategorikan baik, rata-rata kelas eksperimen 76% sedangkan pada kelas kontrol 69.17. Low learning outcomes can be caused by several factors, such as learning processes and learning methods. Another contributing factor worth considering is the student boredom and passiveness in the class. On that ground, the present study was aimed at applying a learning method called mind map method in the subject of computer and basic network; it focused on examining the extent to which the learning method contributed to the student learning outcomes. This quantitative research relied on a quasi-experimental approach. The hypothesis was examined using a t-test with separated variants. According to the result of the test, t-count (7.65) was greater than t-table (1.672), with a significance level of 0.05. In other words, H0 was refuted and H1 was accepted. This result further indicated the significance of the mind map method to the learning outcomes. It was shown that the affective aspect of the learning outcomes of both the experimental group and control group fell under a good category, with a percentage of 76% and 69.17%, respectively

Nanosatellite-class dynamic attitude simulator for hands-on aerospace control education

Due to their low size, mass, development cost and time, nanosatellites have become an increasingly popular tool at universities for providing students with hands-on experience in aerospace education. Among spacecraft subsystems, the attitude determination and control one surely represents a fruitful resource for practicing aerospace control applications. To enable on-ground verification of spacecraft attitude control hardware and software, however, the biggest challenge to overcome is that of providing a representative testing environment. Towards this end, at the µ3S laboratory at the University of Bologna a dynamic hardware in the loop facility has been developed, which allows for testing attitude control subsystems of nanosatellites in the range of 1U to 3U, according to the CubeSat form factor. This paper describes the educational impact that the facility has been having, during both its development and commissioning phases, as well as its early use as a testbed for CubeSats attitude control, which is currently focused on magnetic-based actuation

Kepribadian Tokoh dalam Novel Entrok Karya Okky Madasari

Tujuan penelitian mendeskripsikan kepribadian tokoh pada novel Entrok karya Okky Madasari di lihat dari aspek id, ego dan superego. Penelitian ini menggunakan teori psikologi sastra yang mengkaji tentang kepribadian tokoh dengan menggunakan teori Sigmund Freud yang meliputi Aspek id, ego dan superego. Metode penelitian ini adalah Metode deskriptif kualitatif. Hasil penelitian dan pembahasan menunjukan bahwa, (1) kepribadian tokoh Marni dalam novel Entrok karya Okky Madasari dilihat dari aspek id, ego dan superego. (2) kepribadian tokoh Rahayu dalam novel Entrok karya Okky Madasari dilihat dari aspek id, ego dan superego. (3) kepribadian tokoh Simbok dalam novel Entrok karya Okky Madasari dilihat dari aspek id, ego dan superego. (4) kepribadian tokoh Teja dalam novel Entrok karya Okky Madasari dilihat dari aspek id,ego dan superego

Development of a ground testing facility and attitude control for magnetically actuated nanosatellites

Growing popularity of the highly capable small- and nano-satellites, driven by components miniaturization, face new technological challenges and at the same time provides new opportunities for the whole space sector. Low cost of nanosatellites launches make them accessible. Reliability is an exigency: especially challenging is design and testing of Attitude and Determination Control Systems (ADCS). Demand for nanosatellitesdedicated attitude control algorithms and careful performance assessment of the spacecrafts motivates the research work presented in this thesis. In the first part of the manuscript, development and assessment of the three degreesoffreedom ADCS testbed for nanosatellites testing is described. The facility was developed within the Microsatellites and Space Microsystems Lab at University of Bologna, and designed to meet strict low-cost requirements. The facility includes several integrated subsystems to simulate the on-orbit environment: i) an air-bearing based, three degree of freedom platform with automatic balancing system, ii) a Helmholtz , iii) a Sun simulator, and iv) a metrology vision system . Experimental assessment of the subsystems guarantee necessary level of performance. Control law design for smallsats is addressed in the second part. Limited power availability and reliability makes magnetic actuation particularly suited for ADCS design, but, the control system faces inherent underactuation. To overcome the intrinsic limits of existing control designs, a novel approach to the three-axis attitude control of a magnetically actuated spacecrafts is proposed, based on hybrid systems theory. A local H-inf regulator with guaranteed performance and a global nonlinear controller used for ensuring global stability and robustness, are combined. Hybrid control theory is employed to develop a mixed continuous-discrete controller able to switch between different feedbacks. Analytical results are verified by means of realistic numerical simulations: errors on the state comply with the computed bounds and stability is guaranteed

CHORO RITUAL. UM SÍMBOLO PURIFICADOR EM CONTEXTO ANGOLANO

A realidade angolana actual apresenta-se algo confusa do ponto de vista ritual porquanto um conjunto de rituais outrora significativamente organizados e realizados numa perspectiva ancestral passaram a ser realizados simbolicamente e sem uma percepção clara dos seus principais actores que maioritariamente o evidenciam “mimeticamente” numa espécie de recorrência histórica. Assim, pretende-se com o presente paper, relatar um conjunto de actos simbólicos relativos ao choro ritual e seus desenvolvimentos ao nível da ideia de construção do luto e purificação consubstanciados na ideia de morte que é considerada como uma situação bastante preocupante em termos de poluição. Esta pesquisa baseou-se na observação participante e directa com imensos detalhes obtidos a partir do inquérito por entrevista. Nesta senda, foi possível observar, em contexto angolano, uma continuidade ritualística baseada numa cultura compósita que, naturalmente, resultou de um enorme intercâmbio cultural