Effects of selective dilution on the magnetic properties of La_{0.7}Sr_{0.3}Mn_{1-x}M'_xO_3 (M' = Al, Ti)

The magnetic lattice of mixed-valence Mn ions in La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ is selectively diluted by partial substitution of Al or Ti for Mn. The ferromagnetic transition temperature $T_\mathrm{c}$ and the saturation magnetization $M_\mathrm{s}$ both decrease with substitution. By presenting the data in terms of selective dilution, $T_\mathrm{c}$ in the low-doping region is found to follow the relation $T_\mathrm{c}=T_\mathrm{c0}(1-n_\mathrm{p})$, where $T_\mathrm{c0}$ refers to the undiluted system and $n_\mathrm{p}$ is the dilution concentration defined as $n_\mathrm{p}=x/0.7$ or $n_\mathrm{p}=x/0.3$ for $M^\prime=$ Al or Ti, respectively. The scaling behavior of $T_\mathrm{c}(n_\mathrm{p})$ can be analyzed in the framework of the molecular-field theory and still valid when Mn is substituted by both Al and Ti. The results are discussed with respect to the contributions from ferromagnetic double exchange and other possible antiferromagnetic superexchange interactions coexisting in the material.Comment: Revtex4, 4 pages, 4 figures, 2006 Halong Conference Repor

Optimizing passive acoustic sampling of bats in forests

Passive acoustic methods are increasingly used in biodiversity research and monitoring programs because they are cost-effective and permit the collection of large datasets. However, the accuracy of the results depends on the bioacoustic characteristics of the focal taxa and their habitat use. In particular, this applies to bats which exhibit distinct activity patterns in three-dimensionally structured habitats such as forests. We assessed the performance of 21 acoustic sampling schemes with three temporal sampling patterns and seven sampling designs. Acoustic sampling was performed in 32 forest plots, each containing three microhabitats: forest ground, canopy, and forest gap. We compared bat activity, species richness, and sampling effort using species accumulation curves fitted with the clench equation. In addition, we estimated the sampling costs to undertake the best sampling schemes. We recorded a total of 145,433 echolocation call sequences of 16 bat species. Our results indicated that to generate the best outcome, it was necessary to sample all three microhabitats of a given forest location simultaneously throughout the entire night. Sampling only the forest gaps and the forest ground simultaneously was the second best choice and proved to be a viable alternative when the number of available detectors is limited. When assessing bat species richness at the 1-km(2) scale, the implementation of these sampling schemes at three to four forest locations yielded highest labor cost-benefit ratios but increasing equipment costs. Our study illustrates that multiple passive acoustic sampling schemes require testing based on the target taxa and habitat complexity and should be performed with reference to cost-benefit ratios. Choosing a standardized and replicated sampling scheme is particularly important to optimize the level of precision in inventories, especially when rare or elusive species are expected

Point Detection of Pathogens in Oral Samples

We have outlined our progress with respect to developing a novel device for monitoring oral samples for bacterial and/or viral pathogens. The system is based on an existing device for measuring drugs of abuse in an oral sample. The sample is collected on an absorbent pad that delivers a metered dose to the cassette. The sample is then separated into 4 channels for the detection of antigen, RNA or DNA, and host antibodies to the pathogen. The detection system involves the Upconverting Phosphor Technology (UPT), whereby the captured pathogen analyte is detected by interrogation of the UPT particles with near-infrared light, and the emitted visible light is detected by the analyzer. Several of the steps in this process have already been worked out for viral and/or bacterial pathogens, and most of the remaining effort will be aimed at integrating these steps into a single microfluidic device while maintaining the current sensitivity

Meningkatkan Motivasi Belajar IPS Melalui Penggunaan Media Ganbar Pada Siswa Kelas III Di SDN 05 Bunobogu

Tujuan yang ingin dicapai dalam penelitian ini adalah untuk mengetahui bagaimana media gambar dalam meningkatkan motivasi belajar siswa kelas III SDN Bunobogu dan untuk mengetahui peningkatan hasil belajar siswa pada mata pelajaran Ilmu Pengetahuan Sosial .Penelitian Tindakan Kelas ini adalah di kelas III (tiga) SDN Bunobogu. Dengan jumlah siswa 24 orang. Penelitian ini dilaksanakan dengan menggunakan tehnik observasi dan angket. Fokus penelitian ini adalah meningkatkan motivasi belajar siswa dengan menggunakan media gambar. Penelitian Tindakan Kelas ini dilakukan dengan 2 siklus, diikuti dengan perencanaan pelaksanaan tindakan, observasi dan refleksi. Berdasarkan hasil angket bahwa pada siklus I penggunaan media gambar siswa dapat termotivasi hal ini terlihat dari 24 siswa 18 memilih sangat termotivasi atau 75% sedangkan pada siklus II 21 memilih sangat termotivasi atau 87,5%. Hasil observasi motivasi belajar siswa dalam penggunaan media gambar pada siklus I 78,13% atau baik, pada siklus II meningkat 93,75% atau sangat baik. ini menunjukkan bahwa penggunaan media gambar dapat meningkatkan motivasi belajar siswa pada mata pelajaran IPS di SDN 05 Bunobog

Peningkatan Mutu Tanaman Hias Anggrek Alam Phalaenopsis melalui Kegiatan Persilangan

Phalaenopsis celebencis dan Phalaenopsis venosamerupakan dua jenis anggrek di Sulawesi tengah yang berpotensi sebagai tetua untuk menghasilkan varietas baru anggrek bunga potong. Prospek tanaman anggrek untuk bunga potong dianggap masih sangat cerah untuk dikembangkan. Namun  potensi  ini  belum  dimanfaatkan secara proporsional. Rendahnya produksi anggrek disebabkan  kurang  tersedianya  bibit  bermutu,  budidaya  yang kurang efisien serta penanganan tanaman anggrek yang kurang baik. Untuk memenuhi permintaan pasar yang cenderung meningkat maka diperlukan ketersediaan bibit yang bermutu dan dalam jumlah banyak. Persilangan merupakan salah satu cara meningkatkan mutu tanaman anggrek. Persilangan pada tanaman anggrek tidak bisa terjadi secara alami kecuali pada jenis anggrek tertentu, sehingga diperlukan campur tangan manusia untuk melakukan penyerbukan dengan cara hibridisasi atau persilangan. . Persilangan ini dilakukan untuk memperkaya keaneka-ragaman genetik pada tanaman anggrek. Potensi USAha yang dikembangkan yaitu; USAha pembibitan (perbanyakan),  pembesaran, dan perdagangan. Usaha pengembangan tanaman anggrek dilakukan melalui kegiatan persilangan atau hibridisasi. Hasil yang dicapai dari kegiatan pengabdianini adalah tersedianya indukan anggrek hasil persilangan yang digunakan sebagai sumber eksplan dalam kultur jaringan. Tersedianya anakan-anakan anggrek hybrid hasil persilangan dari hasil kultur jaringan. Dari rangkaian kegiatan ini dapat disimpulkan bahwa target kegiatan berupa tersedianya anakan anggrek dan pemasaran anggrek hasil kultur jaringan dapat tercapai dengan baik. Rangkaian kegiatan memberikan kontribusi besar baik terhadap institusi maupun bagi Masyarakat

Selective dilution and magnetic properties of La_{0.7}Sr_{0.3}Mn_{1-x}M'_xO_3 (M' = Al, Ti)

The magnetic lattice of mixed-valence Mn ions in La$_{0.7}$Sr$_{0.3}$MnO$_3$ is selectively diluted by partial substitution of Mn by Al or Ti. The ferromagnetic transition temperature and the saturation moment decreases with substitution in both series. The volume fraction of the non-ferromagnetic phases evolves non-linearly with the substitution concentration and faster than theoretically expected. By presenting the data in terms of selective dilutions, the reduction of $T_\mathrm{c}$ is found to be scaled by the relative ionic concentrations and is consistent with a prediction derived from molecular-field theory.Comment: 6 pages, 5 figures, REVTex4.0. Submitted to PR