Universal observable detecting all two-qubit entanglement and determinant based separability tests

We construct a single observable measurement of which mean value on four copies of an {\it unknown} two-qubit state is sufficient for unambiguous decision whether the state is separable or entangled. In other words, there exists a universal collective entanglement witness detecting all two-qubit entanglement. The test is directly linked to a function which characterizes to some extent the entanglement quantitatively. This function is an entanglement monotone under so--called local pure operations and classical communication (pLOCC) which preserve local dimensions. Moreover it provides tight upper and lower bounds for negativity and concurrence. Elementary quantum computing device estimating unknown two-qubit entanglement is designed.Comment: 5 pages, RevTeX, one figure replaced by another, tight bounds on negativity and concurrence added, function proved to be a monotone under the pure LOCC, list of authors put in alphabetical orde

Use biochemical markers to evaluate the quality of fresh and cryopreserved semen from the arctic fox (Vulpes lagopus)

The aim of this study was to use biochemical markers to evaluate the quality of fresh and cryopreserved semen from the arctic fox (Vulpes lagopus). Twenty-three manually collected ejaculates were analysed for the main indicators of semen quality (sperm concentration and ejaculate volume). Sperm motility and percentage of morphologically normal and abnormal spermatozoa were determined according to the stage of cryopreservation (fresh - measurement A; equilibrated - measurement B; frozen/thawed - measurement C). Furthermore, the seminal plasma and supernatants were analysed after equilibration and freeze/thawing for the activity of the enzymes alkaline phosphatase (ALP), acid phosphatase (AcP), lactate dehydrogenase (LDH) and aspartate aminotransferase (AspAT), and for the activity of acrosin inhibitors (AP). The mean concentration of sperm was 625.1 million/cm3, and ejaculate volume averaged 1.6 cm3. Seminal plasma was characterized by the highest activity of alkaline phosphatase (3.43×103 U/l) and lowest activity of acrosin inhibitors (4.55×103 U/l). After equilibration, the supernatants showed the highest activity of acid phosphatase (94.9 U/l) and after freeze-thawing, they showed a high activity of lactate dehydrogenase (535.8 U/l) and aspartate aminotransferase (577.1 U/l), which indicates that these proteins had leaked from spermatozoa into the extracellular medium during the biotechnique of semen cryopreservation. In addition, several significant relationships were found between some indicators of semen quality and plasma and/or supernatant enzyme activity

Influence of estrus synchronization of prepubertal gilts on embryo quality

Synchronization and superovulation are commonly used to obtain large numbers of embryos for experimental and practical purposes. This study compared the number, quality, and in vitro development of embryos recovered from gilts following single or double estrus synchronization and superovulation. Prepubertal gilts from the single synchronization group were injected with 1500 I.U. PMSG and 1000 I.U. hCG 72 h later. The double synchronized group of gilts was treated with 750 I.U. PMSG and 500 I.U. hCG 72 h later. After 17 days, 1500 I.U. PMSG followed by 1000 I.U. hCG was administered. Five days after insemination embryos were recovered and cultured for 6 days. Both single and double hormonal stimulation schedules resulted in recovery of elevated numbers of embryos (28.4 and 23.4 vs. 11.3; p<0.01 and p≤0.05, respectively) with a higher percentage of embryos classified as degenerated (39.2% and 43.1%, respectively) compared to the non-stimulated, control group (5.1%). The number of embryos destined for culture did not differ between the single and double synchronized groups. The highest percentage of hatched embryos was observed in the control group. In conclusion, the single synchronization and superovulation schedule is sufficient to obtain high numbers of embryos, however, both synchronization methods resulted in the recovery of considerable numbers of degenerated embryos. A higher number and percentage of hatched embryos after culture was found among embryos from the control group compared to gonadotropin-stimulated gilts.Peer Reviewe

Fertilization rate of Siberian sturgeon (Acipenser baeri, Brandt) milt cryopreserved with methanol

Milt obtained from three Siberian sturgeon males (Acipenser baeri, Brandt) were cryopreserved using three extenders: Tris–sucrose–KCl (30 mM Tris, 23.4 mM sucrose, 0.25 mM KCl, pH 8.0), Tris–NaCl (10 mM Tris, 25 mM NaCl, pH 8.5), and Tris–sucrose (20 mM Tris, 400 mM sucrose, pH 8.0) supplemented with 10% methanol. Semen was diluted 1:1 with appropriate extender and frozen in liquid nitrogen vapor. After fertilization with cryopreserved milt, hatching rates of 29.6±5.0%, 18.2±2.4%, and 6.0±3.0% were recorded for Tris–sucrose–KCl, Tris–NaCl, and Tris–sucrose extender, respectively. Rates for the first two extenders were similar to data of fresh semen obtained from two males(17.9% and 26.0% for male #1 and #2, respectively). Our results indicate that Tris–sucrose–KCl and Tris–NaCl are useful extenders and methanol is a useful cryoprotectant for cryopreservation of sturgeon semen