834 research outputs found

    Kratkotrajno očuvanje sperme potočne pastrmke (salmo trutta macrostigma): delovanje ekstendera na pokretljivost

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    Cilj eksperimenta je bila procena spermatoloških parametara kratkotrajno čuvane sperme potočne pastrmke (Salmo trutta macrostigma) korišćenjem različitih ekstendera. Mleč je uzorkovan od odraslih mužjaka istiskanjem rukom, bez anestezije. Po određivanju najvažnijih karakteristika sperme (volumen, pokretljivost, trajanje pokretljivosti, gustina, pH) uzorci sperme koji su pokazali >80 pokretljivosti su prikupljeni i razblaženi u odnosu 1:3 sa tri različita ekstendera. Razblažena sperma je čuvana 72 sata na 4°C. Tokom čuvanja na svaka 24 h je procenjivan motilitet spermatozoida (%). U zaključku, rezultati studije su pokazali da se ekstender I pokazao boljim od druga 2 za kratkotrajno očuvanje sperme potočne pastrmke

    National Bureau of Economic Research

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    Abstract: Does a one percent increase in aggregate driving increase accident costs by more than one percent? Vickrey [1968] and Edlin [1999] answer yes, arguing that as a new driver takes to the road, she increases the accident risk to others as well as assuming risk herself. On the other hand, more driving could result in increased congestion, lower speeds, and less severe or less frequent accidents. We study the question with panel data on state-average insurance premiums and loss costs. We …nd that in high tra¢c density states, an increase in tra¢c density dramatically increases aggregate insurance premiums and loss costs. In California, for example, we estimate that a typical additional driver increases the total of other people’s insurance costs by 12712432.Incontrast,theaccidentexternalityperdriverinlowtra¢cstatesappearsquitesmall.Onbalance,accidentexternalitiesaresolargethatacorrectingPigouviantaxcouldraise1271-2432. In contrast, the accident externality per driver in low tra¢c states appears quite small. On balance, accident externalities are so large that a correcting Pigouvian tax could raise 45 billion in California alone, and over $140 billion nationally. It is not clear the extent to which this externality results from increases in accident rates, accident severity or both. It is also not clear whether the same externality pertains to underinsured accident costs like fatality risk

    Age-specific life tables of Aonidiella aurantii (Maskell) (Hemiptera: Diaspididae) and its parasitoid Aphytismelinus DeBach (Hymenoptera: Aphelinidae)

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    Abstract: Biological parameters of the California red scale (Aonidiella aurantii [Maskell] [Hemiptera: Diaspididae]) were determined under laboratory conditions at 3 different temperatures (20, 23, and 27 °C) on butternut squash (Cucurbita moschata Duchesne ex Lamarck) (Cucurbitaceae), while the biological parameters of its parasitoid Aphytis melinus DeBach (Hymenoptera: Aphelinidae) were conducted at 27 °C. The survival of A. aurantii ranged between 80.0% and 88.3%. The highest mortality was recorded during the adult stage, with mortalities ranging between 12% and 20%. On C. moschata, the total development time was 93.1 ± 9.73, 81.8 ± 7.13, and 65.7 ± 6.37 days, while the adult longevity was 54.65 ± 0.71, 47.05 ± 0.97, and 39.35 ± 1.07 days at 20, 23, and 27 °C, respectively. The oviposition period of A. aurantii was 44.3 ± 0.51, 40.65 ± 0.41, and 34.5 ± 0.45 days at 20, 23, and 27 °C, respectively. Average fecundity was 73.25 ± 1.827, 109.7 ± 3.569, and 129.35 ± 4.564 individuals at 20, 23, and 27 °C, respectively. For A. melinus, adult longevity was 19.24 ± 0.73 days, and average fecundity 62.7 ± 2.81 eggs at 27 °C. The preoviposition period was 0.82 ± 0.05 days, oviposition period was 15.7 ± 0.52 days, and postoviposition period was 2.21 ± 0.09 days. The intrinsic rate of increase (rm) of A. melinus (0.188 ♀/♀/day) was significantly greater than that of A. aurantii (0.080) at 27 °C. These laboratory results demonstrated that A. melinus is an effective parasitoid for decreasing A. aurantii populations. Fecundity of A. aurantii and A. melinus was determined with the Enkegaard equation. The best-fit parameters of fecundity were calculated as a = 0.410, b = 0.099; a = 0.624, b = 0.098; a = 0.661, b = 0.091; a = 1.190, b = 0.179 for A. aurantii at 20, 23, and 27 °C, and A. melinus at 27 °C, respectively

    Use of a Global Positioning System (GPS) to Manage Extensive Sheep Farming and Pasture Land

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    The terrestrial climate is not sufficient to produce enough food to meet the roughage needs of the animals benefiting from the pasture lands because of excessive and early grazing of those areas. Plant growth is adversely affected in pastures that are not uniformly grazed. Tracking animals using the Global Positioning System (GPS) is a very important factor in determining the uniform distribution of grazing animals in a pasture, increasing the utilization rate of the pasture, and saving costs and time. With GPS tracking systems, establishing more effective pasture-use systems by monitoring the feeding regimes of small animals, the status of feed in the pasture, and the grazing behavior of the animals would be possible. The present study aimed to investigate the use of GPS for pasture and herd management in Turkey in addition to using the traditional techniques.In the present study conducted in the village of Köseyusuflu in Yozgat Province in May 2017, 2018, and 2019, grazing benefits that were determined from the pasture containing two Akkaraman sheep herds were recorded using GPS tracking devices. The results suggested that the area covered with vegetation along the sheep’s spring grazing routes varied between 43.6 and 62.9%, the ratio of legumes in the pasture grass in the low grazing areas was between 0.50 and 4.10%, and the grass species were between 12.75 and 44.50%. We determined that the sheep in herd A traveled between 7.6 and 9.9 km, while the sheep in herd B traveled between 4.7 and 5.7 km daily, and the two herds grazed an average of between 122 and 254 daa

    The Effects of Thermal Procedure on Transformation Temperature, Crystal Structure and Microstructure of Cu-Al-Co Shape Memory Alloy

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    The purpose of this study is to investigate the effects of different thermal procedures of the Cu-Al-Co shape memory alloy on its crystal structure, transformation temperature and microstructure. The alloys were subjected to a heat treatment and then cooling was applied at four different conditions. After the thermal process, XRD, DSC, optical microscopy and micro-hardness measurements were carried out. The experimental studies showed that crystal structure, microstructure and transformation temperature of Cu-Al-Co alloy were changed from the cooling conditions

    Compressive Response of Polycrystalline NiCoMnGa High-Temperature Meta-magnetic Shape Memory Alloys

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    The effects of the addition of quaternary element, Co, to polycrystalline NiMnGa alloys on their magnetic and shape memory properties have been investigated. NiCoMnGa polycrystalline alloys have been found to demonstrate good shape memory and superelasticity behavior under compression at temperatures greater than 100 °C with about 3% transformation strain and low-temperature hysteresis. It is also possible to train the material to demonstrate a large two-way shape memory effect

    The effect of racemic gossypol and AT-101 on angiogenic profile of OVCAR-3 cells: a preliminary molecular framework for gossypol enantiomers

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    To compare the effect of racemic gossypol with its (–)/(–) enantiomer (AT-101) on expression profiles of angiogenic molecules by mRNA levels in human ovarian cancer cell line OVCAR-3. Methods: Cell viability assay (2,3-bis (2-methoxy-4-nitro-5- sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide) was used to detect cytotoxicity of gossypol enantiomers. DNA fragmentation by an enzyme-linked immunosorbent (ELISA) assay was used to evaluate the rate of apoptosis. The mRNA expression levels of angiogenic molecules were investigated by Human Angiogenesis RT2 ProfilerTM PCR Array (SuperArray, Frederick, MD). Results: Both racemic form and AT-101 resulted in a significant cytotoxicity and induced apoptosis. This effect was observed in a dose- and time dependent manner. However, AT-101 was much more potent. In addition, the treatment of 10 μM of racemic gossypol alone and 3 μM of AT-101 alone resulted in significant down-regulation (≥ 3 fold) in mRNA levels of some pivotal angiogenic molecules in OVCAR-3, but altered gene profiles were different by the treatment of each enantiomer. Conclusion: The efficacy of two gossypol enantiomers in OVCAR-3 cells showed distinction. AT-101 was much more potent than racemic gossypol, not only by means of cell death and apoptosis, but also by modulation of angiogenic molecules released from OVCAR-3 cells. Further studies with endothelial cells should be done to verify the anti-angiogenic effect of gossypol enantiomers in cancer treatment

    Dasatinib inhibits site-specific tyrosine phosphorylation of androgen receptor by Ack1 and Src kinases

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    Activation of androgen receptor (AR) may play a role in the development of castration resistant prostate cancer. Two intracellular tyrosine kinases, Ack1 (activated cdc42-associated kinase) and Src, phosphorylate and enhance AR activity and promote prostate xenograft tumor growth in castrated animals. However, the upstream signals that activate these kinases and lead to AR activation are incompletely characterized. In this study, we investigated AR phosphorylation in response to non-androgen ligand stimulation using phospho-specific antibodies. Treatment of LNCaP and LAPC-4 cells with epidermal growth factor (EGF), heregulin, Gas6 (ligand binding to Mer receptor tyrosine kinase and activating Ack1 downstream), interleukin (IL)-6 or bombesin stimulated cell proliferation in the absence of androgen. Treatment of LNCaP and LAPC-4 cells with EGF, heregulin, or Gas6 induced AR phosphorylation at Tyr-267; IL-6 or bombesin treatment did not. AR phosphorylation at Tyr-534 was induced by treatment with EGF, IL-6 or bombesin, but not by heregulin or Gas6. siRNA-mediated knockdown of Ack1 or Src showed that Ack1 mediates heregulin- and Gas6-induced AR Tyr-267 phosphorylation whereas Src mediates Tyr-534 phosphorylation induced by EGF, IL-6, and bombesin. Dasatinib, a Src inhibitor, blocked EGF-induced Tyr-534 phosphorylation. In addition, we show dasatinib also inhibited Ack1 kinase. Dasatinib inhibited heregulin-induced Ack1 kinase activity and AR Tyr-267 phosphorylation. Dasatinib inhibited heregulin-induced AR-dependent reporter activity. Dasatinib also inhibited heregulin-induced expression of endogenous AR target genes. Dasatinib inhibited Ack1-dependent colony formation and prostate xenograft tumor growth in castrated mice. Interestingly, Ack1 or Src knockdown or dasatinib did not inhibit EGF-induced AR Tyr-267 phosphorylation or EGF-stimulated AR activity, suggesting the existence of an additional tyrosine kinase that phosphorylates AR at Tyr-267. These data suggest that specific tyrosine kinases phosphorylate AR at distinct sites and that dasatinib may exert anti-tumor activity in prostate cancer through inhibition of Ack1

    Post-Partum Pituitary Insufficiency and Livedo Reticularis Presenting a Diagnostic Challenge in a Resource Limited Setting in Tanzania: A Case Report, Clinical Discussion and Brief Review of Existing Literature.

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    Pituitary disorders following pregnancy are an important yet under reported clinical entity in the developing world. Conversely, post partum panhypopituitarism has a more devastating impact on women in such settings due to high fertility rates, poor obstetric care and scarcity of diagnostic and therapeutic resources available. A 37 year old African female presented ten years post partum with features of multiple endocrine deficiencies including hypothyroidism, hypoadrenalism, lactation failure and secondary amenorrhea. In addition she had clinical features of an underlying autoimmune condition. These included a history of post-partum thyroiditis, alopecia areata, livedo reticularis and deranged coagulation indices. A remarkable clinical response followed appropriate hormone replacement therapy including steroids. This constellation has never been reported before; we therefore present an interesting clinical discussion including a brief review of existing literature. Post partum pituitary insufficiency is an under-reported condition of immense clinical importance especially in the developing world. A high clinical index of suspicion is vital to ensure an early and correct diagnosis which will have a direct bearing on management and patient outcome
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