56 research outputs found

    Specific heat and magnetocaloric effect in Pr1-xAgxMnO3 manganites

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    The magnetocaloric effect in alternating magnetic fields has been investigated in Pr1-xAgxMnO3 manganites with x=0.05-0.25. The stepwise reversal of the sign of the magnetocaloric effect has been revealed in a weakly doped sample (x=0.05) at low temperatures (~80 K). This reversal is attributed to the coexistence of the ferromagnetic and canted antiferromagnetic phases with different critical temperatures.Comment: 4 pages, 4 figure

    Growth, Fecundity, and Diets of Newly Established Silver Carp in the Middle Mississippi River

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    The silver carp Hypophthalmichthys molitrix has spread throughout the Mississippi River drainage. During 2003, we determined its population status and potential impact in the middle Mississippi River (MMR), the conduit between the lower Mississippi River and the upper Mississippi, Missouri, and Illinois rivers. We quantified growth, age structure, fecundity, and diets of silver carp sampled with trammel nets and AC electrofishing in main-channel areas. Mean length at age in the MMR exceeded that of populations in Asia by as much as 26%. Individuals were typically more than 1 year old and 230 mm total length, suggesting that small, young fish were absent. Individuals in this population matured earlier (age 2) than in the species\u27 native range. Regardless of phytoplankton variation (using chlorophyll a as a surrogate) and zooplankton concentration at MMR sites, phytoplankton was consistently most abundant in diets. Silver carp are finding suitable resources within the MMR, allowing individuals to grow rapidly during early life, persist as adults, and successfully disperse upstream

    Linking Adult Reproduction and Larval Density of Invasive Carp in a Large River

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    Identifying how temporal variation in the environment affects reproductive success of invasive alien species will aid in predicting future establishment and tracking dynamics of established populations. Asian carp Hypophthalmichthys spp. have become a nuisance in recent years in the Mississippi River basin. Their populations are apparently expanding, indicating favorable conditions for reproduction. During 2004 and 2005, we quantified mean density of Asian carp larvae, mean monthly gonadosomatic index (GSI) of adult males and females, and number of eggs within mature females in the lower Illinois River, a major tributary of the Mississippi River. A flood (water velocity ≥ 0.7 m/s) and drought (\u3c0.2 m/s) occurred during apparent spawning in 2004 and 2005, respectively. During 2004, Asian carp larvae were found during 32% of sampling weeks; mean GSI and fecundity were relatively low for adults, probably reflecting partially spawned individuals and perhaps low reproductive investment. During the drought of 2005, larval stages were present during only one (5%) of the sampling weeks, whereas mean GSI and fecundity of adults were high through summer. Females resorbed their eggs instead of spawning during this year. Spawning conditions during low water periods appear to be unsuitable for Asian carps, inhibiting adult spawning and yielding few larvae. Spawning conditions during 2004 were better but still yielded low densities of larvae relative to native fishes. Reproduction in the lower Illinois River appears to be linked to river flow and its impact on adult spawning decisions, but conditions for strong year-class production (i.e., high larval densities) may be rarer than previously expected

    Thermodynamic Properties of Methanol in the Critical and Supercritical Regions

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    Distribution of congenital anomals in children, risk factors

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    In world congenital anomalies are serious medical and social problem.  They doubled over last decade 20th century and played significant role in the structure pathology and mortality in the infant, perinatal and children. Now time is 1800 out of 10,000 children born with congenital anomalies. Through progress made in our country in the future reform health system strengthening and the protection of the health children, congenital abnormalities play leading role in the structure morbidity disability and mortality. Reasons development of 40-60% anomalies is unknown. Apply the term "sporadic the defect of birth", meaning unknown cause, accidental appearance and low risk re appearance have future children. For 20-25% of anomalies more likely "multi-factor" reason - complex interaction many small genetic defects and risk factors environmental environment. The rest 10-13% of anomalies associated with the influence environment. Only 12-25% of anomalies have purely genetic causes (Akhmadalieva et al., 2020). Statistics shows disproportionate a high proportion of the total number survivors newborns premature children who suffer physical, intellectual and emotional disability

    Development of an Asian Carp Size Structure Index and Application through Demonstration

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    Asian carp (Cyprinidae) are among the most invasive fishes in North America, but assessment tools for evaluating stock structure have not been established. Thus, we used data from national and international published reports or manuscripts to develop standard length categories for four species of Asian carp. Due to the similarities in maximum reported size for Bighead Carp Hypophthalmichthys nobilis and Grass Carp Ctenopharyngodon idella, we propose the following standardized length categories for those two species: stock = 30 cm, quality = 54 cm, preferred = 68 cm, memorable = 89 cm, and trophy = 111 cm. Proposed Black Carp Mylopharyngodon piceus length categories are stock = 40 cm, quality = 72 cm, preferred = 90 cm, memorable = 118 cm, and trophy = 148 cm. Finally, we propose the following length categories for Silver Carp H. molitrix: stock = 25 cm, quality = 45 cm, preferred = 56 cm, memorable = 74 cm, and trophy = 93 cm. We then used existing data collected in the Illinois River and Mississippi River from 2003 to 2011 to evaluate Silver Carp proportional size distribution (PSD). Incremental PSD provided a temporal index of Silver Carp size structure in the Illinois River and strong cohorts could be followed through the incremental PSD values over time. Traditional PSD provided a quantifiable, comparative index of Silver Carp size structure among two locations in the Mississippi River and one location in the Illinois River. We believe this index provides an additional tool for fisheries managers to evaluate size structure of Asian carp and help assess overall population status
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