Origin of the peculiar eccentricity distribution of the inner cold Kuiper belt

Dawson and Murray-Clay (2012) pointed out that the inner part of the cold population in the Kuiper belt (that with semi major axis a<43.5 AU) has orbital eccentricities significantly smaller than the limit imposed by stability constraints. Here, we confirm their result by looking at the orbital distribution and stability properties in proper element space. We show that the observed distribution could have been produced by the slow sweeping of the 4/7 mean motion resonance with Neptune that accompanied the end of Neptune's migration process. The orbital distribution of the hot Kuiper belt is not significantly affected in this process, for the reasons discussed in the main text. Therefore, the peculiar eccentricity distribution of the inner cold population can not be unequivocally interpreted as evidence that the cold population formed in-situ and was only moderately excited in eccentricity; it can simply be the signature of Neptune's radial motion, starting from a moderately eccentric orbit. We discuss how this agrees with a scenario of giant planet evolution following a dynamical instability and, possibly, with the radial transport of the cold population.Comment: in press in Icaru

Stabilization of solitons of the multidimensional nonlinear Schrodinger equation: Matter-wave breathers

We demonstrate that stabilization of solitons of the multidimensional Schrodinger equation with a cubic nonlinearity may be achieved by a suitable periodic control of the nonlinear term. The effect of this control is to stabilize the unstable solitary waves which belong to the frontier between expanding and collapsing solutions and to provide an oscillating solitonic structure, some sort of breather-type solution. We obtain precise conditions on the control parameters to achieve the stabilization and compare our results with accurate numerical simulations of the nonlinear Schrodinger equation. Because of the application of these ideas to matter waves these solutions are some sort of matter breathers

Durabilidad del hormigón. programa de investigación del IETcc

[ES] El comportamiento de los morteros y hormigones sometidos a la acción de ambientes agresivos naturales (atmósferas; terrenos; aguas —puras, con componentes disueltos, residuales, de mar—, etc.) ha sido objeto.de numerosos trabajos como consecuencia de la gran cantidad de obras construidas a base de hormigón, en masa y armado, las cuales han sufrido lesiones de consideración que, en determinados casos, supusieron fracasos resonantes como consecuencia de la descomposición experimentada; de aquí, que sea un tema que ha preocupado y sigue interesando a los profesionales, no sólo desde un punto de vista tecnológico o constructivo sino científico, para conocer las causas que producen la destrucción de dichas^ obras y poder tomar, en su caso, las medidas oportunas.Peer reviewe

Stable propagation of pulsed beams in Kerr focusing media with modulated dispersion

We propose the modulation of dispersion to prevent collapse of planar pulsed beams which propagate in Kerr-type self-focusing optical media. As a result, we find a new type of two-dimensional spatio-temporal solitons stabilized by dispersion management. We have studied the existence and properties of these solitary waves both analytically and numerically. We show that the adequate choice of the modulation parameters optimizes the stabilization of the pulse.Comment: 3 pages, 3 figures, submitted to Optics Letter

Airflow and Thermal Behavior within Peaches Packaging Box Using Computational Fluid Dynamics - A Preliminary Study

Post-harvest cold storage of peaches is an essential element to maintain the quality of the fruits without any loss. This work aims to present a CFD model, to predict airflow patterns and temperature profiles in ventilated packaging systems, during the forced-air cooling of Peaches stored in a cold chamber. Transient CFD simulations are performed for the chamber containing four ventilated boxes and the evaluation of the results show that the temperature removal near the vent holes and the hand holes is relatively high when compared to other regions of the packaging box. This preliminary study reveals the airflow behavior develop an uneven temperature distribution within the box. To overcome the flaws, future work is focused on modifying the vent hole design to improve the airflow phenomenon to maintain the temperature homogeneity throughout the box. Keywords: Peach, Computational fluid dynamics, Airflow, Heat transfer, Packagin

Inventory Of Seagrass Types In Talise Waters, Best Likupang District, North Minahasa, North Sulawesi

Seagrasses are the only group of flowering plants (Angiosperms) that live permanently in shallow coastal waters and play a key ecological role. Seagrasses are widely distributed in coastal waters around the world where the substrate and depth are suitable for growth. This research was conducted in the waters of Talise Island, Tambun Village, North Minahasa Regency, North Sulawesi Province. carried out using the cruising survey method. The data taken was carried out when the water conditions were in the dead moon phase, where the water experienced the lowest receding. Overall, 5 species of seagrass were found.Keywords: Seagrass; ecological role; Talise Island.AbstrakLamun (seagrass) adalah satu-satunya kelompok tumbuhan berbunga (Angiospermae) yang hidup secara tetap di lingkungan perairan pantai yang dangkal dan merupakan kunci dalam peranan ekologis. Lamun tersebar luas di perairan pantai di seluruh dunia yang substrat serta kedalaman cocok bagi pertumbuhannya. Penelitian ini dilaksanakan di Perairan Pulau Talise, Kampung Tambun, Kabupaten Minahasa Utara, Provinsi Sulawesi Utara. dilakukan dengan menggunakan metode survei jelajah. Data yang diambil, dilakukan pada saat kondisi perairan pada fase bulan mati, dimana air mengalami surut terendah. secara keseluruhan ditemukan jenis-jenis lamun sebanyak 5 spesies.Kata kunci: Lamun; Peranan ekologis; Pulau Talise

Study of Long Weight Relation of Scylla serrata In Mangrove Forest Around The Wet Laboratory FPIK Eeast Likupang District North Minahasa

Mud crab (Scylla serrata) is a ten-legged crustacean animal from Brachura infraordo, known to have a very short tail (in Greek: brachy = short, ura = tail). Mangrove crab is one of the aquatic biota that has significant economic value and its life is strongly influenced by the existence of mangrove forest. The purpose of this study is to identify and analyze the relationship of weight and growth patterns of mangrove crab (Scylla serrata). Sampling is obtained by catching activities using fishing gear that is bubu (chang). Based on the results of research conducted in the area of Mangrove Forest around Wet Laboratory Faculty of Fisheries and Marine Sciences, Likupang Timur in August - September 2017. Mangrove crab (Scylla serrata) in the can through research obtained as many as 32 individuals.Keywords: Mangrove Crab (Scylla serrata), Long Weight Relation, Growth Pattern, East Likupang ABSTRAKKepiting bakau (Scylla serrata) adalah binatang anggota crustasea berkaki sepuluh dari infraordo Brachura, yang dikenal mempunyai ekor yang sangat pendek (dalam bahasa Yunani : brachy = pendek, ura = ekor). Kepiting bakau adalah salah satu biota perairan yang bernilai ekonomis penting dan kehidupannya sangat dipengaruhi oleh keberadaan hutan mangrove. Adapun tujuan dari penelitian ini yaitu untuk mengidentifikasi dan menganalisis hubungan panjang berat berserta pola pertumbuhan dari kepiting bakau (Scylla serrata). Pengambilan sampel diperoleh dengan melakukan kegiatan penangkapan menggunakan alat tangkap yaitu bubu (chang). Berdasarkan hasil penelitian yang dilakukan di Daerah Hutan Mangrove sekitar Laboratorium Basah Fakultas Perikanan dan Ilmu Kelautan, Likupang Timur pada bulan Agustus – September 2017. Kepiting bakau (Scylla serrata) yang di dapat selama melalukan penelitian diperoleh sebanyak 32 individu. Kata Kunci : Kepiting Bakau (Scylla serrata), Hubungan Panjang Berat, Pola  Pertumbuhan, Likupang Timur