Efikasnost ulja karanfilića kao anestetika za cverglana (Ictalurus punctatus raf.)

Cilj rada je bio da se odredi optimalna koncetracija ulja karanfilića potrebna za anesteziju i oporavak dvogodišnjeg cverglana. Eksperimenti su izvedeni u laboratorijskim uslovima. Ispitivano je dejstvo tri koncentracije: 0.02 ml.l-1, 0.04 ml.l-1 i 0.06 ml.l-1. Tokom procesa anesteziranja je praćeno i analizirano ponašanje riba. Koncetracija od 0.02 ml.l-1 je imala sedativan efekat na ribe i dovela do poremećaja ravnoteže. Pri koncentraciji od 0.04 ml.l-1 90% riba je bilo potpuno imobilisano u roku od 3.17 to 6 min. Pri najvišoj koncetraciji, od 0.06 ml.l-1, sve ribe su bile potpuno imobilisane u roku od 2 do 4 minuta

Raman and Infrared-Active Phonons in Hexagonal HoMnO3_3 Single Crystals: Magnetic Ordering Effects

Polarized Raman scattering and infrared reflection spectra of hexagonal HoMnO$_3$ single crystals in the temperature range 10-300 K are reported. Group-theoretical analysis is performed and scattering selection rules for the second order scattering processes are presented. Based on the results of lattice dynamics calculations, performed within the shell model, the observed lines in the spectra are assigned to definite lattice vibrations. The magnetic ordering of Mn ions, which occurs below T$_N$=76 K, is shown to effect both Raman- and infrared-active phonons, which modulate Mn-O-Mn bonds and, consequently, Mn exchange interaction.Comment: 8 pages, 6 figure

Upper limits on the 21 cm Epoch of Reionization power spectrum from one night with LOFAR

We present the first limits on the Epoch of Reionization 21 cm H I power spectra, in the redshift range z = 7.9–10.6, using the Low-Frequency Array (LOFAR) High-Band Antenna (HBA). In total, 13.0 hr of data were used from observations centered on the North Celestial Pole. After subtraction of the sky model and the noise bias, we detect a non-zero I 56 13 mK D2 = 2 ( ) (1-σ) excess variance and a best 2-σ upper limit of 21 79.6 mK D2 < 2 ( ) at k = 0.053 h cMpc−1 in the range z = 9.6–10.6. The excess variance decreases when optimizing the smoothness of the direction- and frequency dependent gain calibration, and with increasing the completeness of the sky model. It is likely caused by (i) residual side-lobe noise on calibration baselines, (ii) leverage due to nonlinear effects, (iii) noise and ionosphere-induced gain errors, or a combination thereof. Further analyses of the excess variance will be discussed in forthcoming publications