Solution to Problem 1751, A Combinatorial Identity

A combinatorial proof to Iliya Bluskov\u27s proposed Problem 1751

Unitary coupled-channels model for three-mesons decays of heavy mesons

A unitary coupled-channels model is presented for investigating the decays of heavy mesons and excited meson states into three light pseudoscalar mesons. The model accounts for the three-mesons final state interactions in the decay processes, as required by both the three-body and two-body unitarity conditions. In the absence of the Z-diagram mechanisms that are necessary consequences of the three-body unitarity, our decay amplitudes are reduced to a form similar to those used in the so-called isobar-model analysis. We apply our coupled-channels model to the three-pions decays of a1(1260), pi2(1670), pi2(2100), and D0 mesons, and show that the Z-diagram mechanisms can contribute to the calculated Dalitz plot distributions by as much as 30% in magnitudes in the regions where f0(600), rho(770), and f2(1270) dominate the distributions. Also, by fitting to the same Dalitz plot distributions, we demonstrate that the decay amplitudes obtained with the unitary model and the isobar model can be rather different, particularly in the phase that plays a crucial role in extracting the CKM CP-violating phase from the data of B meson decays. Our results indicate that the commonly used isobar model analysis must be extended to account for the final state interactions required by the three-body unitarity to reanalyze the three-mesons decays of heavy mesons, thereby exploring hybrid or exotic mesons, and signatures of physics beyond the standard model.Comment: 32 pages, 10 figures. Version to appear in PR

Exclusive electromagnetic production of strangeness on the nucleon : review of recent data in a Regge approach

In view of the numerous experimental results recently released, we provide in this letter an update on the performance of our simple Regge model for strangeness electroproduction on the nucleon. Without refitting any parameters, a decent description of all measured observables and channels is achieved. We also give predictions for spin transfer observables, recently measured at Jefferson Lab which have high sensitivity to discriminate between different theoretical approaches.Comment: 5 pages, 5 figure

Tingkah Laku Memijah, Potensi Reproduksi Ikan Betina, dan Optimasi Teknik Pemijahan Ikan Pelangi Iriatherina Werneri Meinken, 1974 [Spawning Behavior, Female Reproductive Potential And Breeding Technique Optimize Of Threadfin Rainbowfish...............

Informasi reproduksi ikan pelangi Iriatherina werneri pada wadah terkontrol masih sedikit diketahui. Oleh karena itu, diperlukan kajian mengenai tingkah laku memijah, potensi reproduksi ikan betina berdasarkan perbedaan pakan (buatan dan alami), dan optimasi teknik pemijahan. Kajian optimasi pemijahan meliputi pengamatan pengaruh perbedaan sistem pemijahan (massal atau individual), perbedaan rasio kelamin pemijahan jantan : betina (1:1, 1:2, dan 1:3), serta perbedaan ukuran betina (kecil, sedang, dan besar) untuk mendukung kegiatan budi daya. Hasil penelitian menunjukkan bah-wa pemijahan ikan pelangi terjadi pada 13-15 jam sejak pemasangan ikan jantan dan betina yang diawali oleh gerakan ikan jantan mengembangkan dan menguncupkan sirip. Telur yang dikeluarkan pada pemijahan massal berakhir dua jam lebih cepat dibandingkan pemijahan individual dan telur lebih serempak dikeluarkan pagi hari (94,92%). Ikan pelangi merupakan pemijah bertahap yang mampu memijah setiap hari selama 30 hari. Potensi jumlah telur dan larva yang di-hasilkan seekor betina dapat ditingkatkan masing-masing sebanyak empat kali lipat dan 14 kali lipat melalui pemberian pakan alami. Optimasi teknik pemijahan I. werneri dicapai dengan menggunakan sistem massal dengan rasio kelamin 1: 3 dan menggunakan ikan betina berukuran 26,98-35,76 mm

Coherent control using adaptive learning algorithms

We have constructed an automated learning apparatus to control quantum systems. By directing intense shaped ultrafast laser pulses into a variety of samples and using a measurement of the system as a feedback signal, we are able to reshape the laser pulses to direct the system into a desired state. The feedback signal is the input to an adaptive learning algorithm. This algorithm programs a computer-controlled, acousto-optic modulator pulse shaper. The learning algorithm generates new shaped laser pulses based on the success of previous pulses in achieving a predetermined goal.Comment: 19 pages (including 14 figures), REVTeX 3.1, updated conten

Keragaman Genotipe dan Morfometrik Ikan Tengadak Barbonymus Schwanenfeldii (Bleeker 1854) Asal Sumatera, Jawa, dan Kalimantan

Studi keragaman genotipe dan fenotipe populasi awal ikan tengadak (Barbonymus schwanenfeldii) asal Sumatera, Jawa, dan Kalimantan merupakan upaya pemanfaatan sumber daya genetik ikan tengadak untuk kegiatan budi daya secara berkelanjutan. Tujuan penelitian ini adalah melakukan evaluasi keragaman genotipe dan fenotipe ikan tengadak asal Sumatera, Jawa, dan Kalimantan. Analisis keragaman genotipe dilakukan secara molekuler dengan metode Random Amplified Polymorphism DNA (RAPD) menggunakan primer OPA 08, OPA 09 dan OPC 02 sedangkan keragaman fenotipe dilakukan berdasarkan pengukuran truss morphometric. Hasil penelitian menunjukkan polimorfisme genetik tertinggi (40%) ditemukan pada ikan jantan populasi asal Jawa dan ikan betina asal Kalimantan dengan nilai heterozi- gositas tertinggi 0,18 sedangkan polimorfisme terendah (18%) ditemukan pada ikan betina populasi asal Jawa dengan tingkat heterozigositas 0,08. Jarak genetik ketiga populasi berkisar 0,48-0,55 sedangkan antara ikan jantan dan betina berki-sar 0,19-0,24. Hasil analisis fungsi kanonikal truss morfometrik ikan tengadak pada 21 karakter terukur menun- jukkan sebaran pengukuran ketiga populasi berada pada kuadran yang berbeda. Persentase indeks keseragaman intra- populasi menunjukkan indeks keseragaman genetik tertinggi pada populasi Jawa (66,7-86,7 %) dengan indeks kesera- gaman interpopulasi (0-6%) pada populasi Kalimantan dan (0%) pada populasi Sumatera. Berdasarkan data keragaman genotipe dan fenotipe ikan jantan asal Jawa dan ikan betina asal Kalimantan berpotensi sebagai sumber genetik donor untuk pengembangan budidaya ikan tengadak

The wall shear rate distribution for flow in random sphere packings

The wall shear rate distribution P(gamma) is investigated for pressure-driven Stokes flow through random arrangements of spheres at packing fractions 0.1 <= phi <= 0.64. For dense packings, P(gamma) is monotonic and approximately exponential. As phi --> 0.1, P(gamma) picks up additional structure which corresponds to the flow around isolated spheres, for which an exact result can be obtained. A simple expression for the mean wall shear rate is presented, based on a force-balance argument.Comment: 4 pages, 3 figures, 1 table, RevTeX 4; significantly revised with significantly extended scop