Grafting melons onto potential cucumis spp. rootstocks

Cucumís melo is an economically importar]t crop. Its culture is hampered by differen t types of soil stresses. Grafting melons onto different resistant cucurbits belonging to the genera, Cucurbíta, Lagenaría, Luffa, etc. have been successfully used to avoid these problems. However, me Ion quality has been nega.tively modified as a consequence of grafting. In general, variation in fruit shape, seed cavity and sugar content have been observed. The use of rootstocks more genetically c\oser to the melon scions could be useful to obtain fru i ts with better quality from melon grafted plantsPostprint (published version

Pengaruh Pemberian Ekstrak Biji Pinang (Areca Catechu L.) terhadap Waktu Perdarahan Pasca Ekstraksi Gigi pada Tikus Jantan Wistar (Rattus Norvegicus L.)

PENGARUH PEMBERIAN EKSTRAK BIJI PINANG (ARECA CATECHU L.) TERHADAP WAKTU PERDARAHAN PASCA EKSTRAKSI GIGI PADA TIKUS JANTAN WISTAR (RATTUS NORVEGICUS L.) ABSTRAK Biji pinang (Areca catechu L.) merupakan salah satu tanaman obat yang dikenal masyarakat dapat menghentikan perdarahan. Penelitian ini bertujuan untuk mengetahui pengaruh pemberian ekstrak biji pinang terhadap waktu perdarahan pasca ekstraksi gigi pada tikus jantan galur Wistar. Pada penelitian ini metode yang digunakan merupakan eksperimental. Ekstrak biji pinang didapatkan dengan cara maserasi dan penguapan menggunakan Rotary vacuum evaporator. Jumlah sampel sebanyak 24 ekor tikus jantan galur Wistar yang dibagi dalam 3 kelompok. Sampel penelitian kelompok perlakuan terdiri dari 8 ekor tikus jantan galur Wistar. Delapan sampel kelompok perlakuan diberi ekstrak biji pinang dosis 13,834 mg/200 g BB. Perhitungan dosis menggunakan tabel faktor konversi. Proses ekstraksi gigi tikus dilakukan setelah 4 jam pemberian ekstrak. Pemeriksaan waktu perdarahan dimulai saat gigi telah terlepas dari soket dengan melihat darah yang keluar sampai mulai terbentuknya bekuan darah pada soket. Perhitungan waktu perdarahan menggunakan stopwatch. Hasil penelitian menunjukkan rerata waktu perdarahan kelompok perlakuan yaitu 0.6125 (menit.detik). Rerata waktu perdarahan kelompok perlakuan tidak jauh berbeda dengan rerata waktu perdarahan kelompok kontrol positif yang diberi transamin yaitu 0.3475 (menit.detik) dan lebih singkat dari kelompok kontrol negatif etanol 96% dengan rerata waktu perdarahan 1.79 (menit.detik). Penelitian yang telah dilakukan menyimpulkan terdapat pengaruh pemberian ekstrak biji pinang (Areca catechu L.) dosis 13,834 mg/200 g BB terhadap waktu perdarahan pasca ekstraksi gigi pada tikus jantan galur Wistar. Kata kunci: Biji pinang, waktu perdarahan, ekstraksi gigi THE EFFECT OF BETEL NUT (Areca catechu L.) EXTRACT ON BLEEDING TIME AFTER EXTRACTION IN WISTAR MALE RATS (Rattus norvegicus L.) ABSTRACT The betel nut (Areca catechu L.) is a medicinal plant known by society to halt bleeding. This study was aimed to know the effect of betel nut extract administration on bleeding time after teeth extraction in Wistar male rats. This study was an experimental study. Betel nut extracts were obtained by maceration and evaporation using Rotary vacuum evaporator. The number of samples were 24 Wistar male rats divided into three groups. The treatment group consisted of 8 Wistar male rats. Eight samples of treatment group were fed with betel nut extract at dosage of 13,834 mg/200 g body weight. Dosages were calculated using conversion factor table. The rats teeth were extracted 4 hours after betel nut extract administration. Evaluation of bleeding time was started from the loss of extracted teeth from socket by observing the shed blood to the formation of blood clots in the socket. The bleeding time was calculated using stopwatch. Study results indicated that average bleeding time in treatment group namely 0.6125 (minute.second). The average bleeding time in treatment group did not differ significantly from average bleeding time in positive control group fed with transamine namely 0.3475 (minute.second), and shorter from negative control group fed with 96% ethanol with average bleeding time of 1.79 (minute.second). This study concluded that there was an effect of betel nut extract (Areca catechu L.) administration at dosage of 13,834 mg/200 g body weight on bleeding time after teeth extraction in Wistar male rats

Robustness of the European power grids under intentional attack

The power grid defines one of the most important technological networks of our times and sustains our complex society. It has evolved for more than a century into an extremely huge and seemingly robust and well understood system. But it becomes extremely fragile as well, when unexpected, usually minimal, failures turn into unknown dynamical behaviours leading, for example, to sudden and massive blackouts. Here we explore the fragility of the European power grid under the effect of selective node removal. A mean field analysis of fragility against attacks is presented together with the observed patterns. Deviations from the theoretical conditions for network percolation (and fragmentation) under attacks are analysed and correlated with non topological reliability measures.Comment: 7 pages, 4 figure

Beating noise with abstention in state estimation

We address the problem of estimating pure qubit states with non-ideal (noisy) measurements in the multiple-copy scenario, where the data consists of a number N of identically prepared qubits. We show that the average fidelity of the estimates can increase significantly if the estimation protocol allows for inconclusive answers, or abstentions. We present the optimal such protocol and compute its fidelity for a given probability of abstention. The improvement over standard estimation, without abstention, can be viewed as an effective noise reduction. These and other results are exemplified for small values of N. For asymptotically large N, we derive analytical expressions of the fidelity and the probability of abstention, and show that for a fixed fidelity gain the latter decreases with N at an exponential rate given by a Kulback-Leibler (relative) entropy. As a byproduct, we obtain an asymptotic expression in terms of this very entropy of the probability that a system of N qubits, all prepared in the same state, has a given total angular momentum. We also discuss an extreme situation where noise increases with N and where estimation with abstention provides a most significant improvement as compared to the standard approach

Nonlinear Jaynes-Cummings model of atom-field interaction

Interaction of a two-level atom with a single mode of electromagnetic field including Kerr nonlinearity for the field and intensity-dependent atom-field coupling is discussed. The Hamiltonian for the atom-field system is written in terms of the elements of a closed algebra, which has SU(1,1) and Heisenberg-Weyl algebras as limiting cases. Eigenstates and eigenvalues of the Hamiltonian are constructed. With the field being in a coherent state initially, the dynamical behaviour of atomic-inversion, field-statistics and uncertainties in the field quadratures are studied. The appearance of nonclassical features during the evolution of the field is shown. Further, we explore the overlap of initial and time-evolved field states.Comment: 14 pages, 6 figures is PS forma

On the origin of ambiguity in efficient communication

This article studies the emergence of ambiguity in communication through the concept of logical irreversibility and within the framework of Shannon's information theory. This leads us to a precise and general expression of the intuition behind Zipf's vocabulary balance in terms of a symmetry equation between the complexities of the coding and the decoding processes that imposes an unavoidable amount of logical uncertainty in natural communication. Accordingly, the emergence of irreversible computations is required if the complexities of the coding and the decoding processes are balanced in a symmetric scenario, which means that the emergence of ambiguous codes is a necessary condition for natural communication to succeed.Comment: 28 pages, 2 figure

Near-infrared Linear Polarization of Ultracool Dwarfs

We report on near-infrared J- and H-band linear polarimetric photometry of eight ultracool dwarfs (two late-M, five L0-L7.5, and one T2.5) with known evidence for photometric variability due to dust clouds, anomalous red infrared colors, or low-gravity atmospheres. The polarimetric data were acquired with the LIRIS instrument on the William Herschel Telescope. We also provide mid-infrared photometry in the interval 3.4-24 micron for some targets obtained with Spitzer and WISE, which has allowed us to confirm the peculiar red colors of five sources in the sample. We can impose modest upper limits of 0.9% and 1.8% on the linear polarization degree for seven targets with a confidence of 99%. Only one source, 2MAS, J02411151-0326587 (L0), appears to be strongly polarized (P ~ 3%) in the J-band with a significance level of P/sigma_P ~ 10. The likely origin of its linearly polarized light and rather red infrared colors may reside in a surrounding disk with an asymmetric distribution of grains. Given its proximity (66 +/- 8 pc), this object becomes an excellent target for the direct detection of the disk.Comment: Accepted for publication in Ap

Nanosecond spin lifetimes in single- and few-layer graphene-hBN heterostructures at room temperature

We present a new fabrication method of graphene spin-valve devices which yields enhanced spin and charge transport properties by improving both the electrode-to-graphene and graphene-to-substrate interface. First, we prepare Co/MgO spin injection electrodes onto Si$^{++}$/SiO$_2$. Thereafter, we mechanically transfer a graphene-hBN heterostructure onto the prepatterned electrodes. We show that room temperature spin transport in single-, bi- and trilayer graphene devices exhibit nanosecond spin lifetimes with spin diffusion lengths reaching 10$\mu$m combined with carrier mobilities exceeding 20,000 cm$^2$/Vs.Comment: 15 pages, 5 figure

Topological reversibility and causality in feed-forward networks

Systems whose organization displays causal asymmetry constraints, from evolutionary trees to river basins or transport networks, can be often described in terms of directed paths (causal flows) on a discrete state space. Such a set of paths defines a feed-forward, acyclic network. A key problem associated with these systems involves characterizing their intrinsic degree of path reversibility: given an end node in the graph, what is the uncertainty of recovering the process backwards until the origin? Here we propose a novel concept, \textit{topological reversibility}, which rigorously weigths such uncertainty in path dependency quantified as the minimum amount of information required to successfully revert a causal path. Within the proposed framework we also analytically characterize limit cases for both topologically reversible and maximally entropic structures. The relevance of these measures within the context of evolutionary dynamics is highlighted.Comment: 9 pages, 3 figure