Fatty acid and squalene compositions of mediterraneanCentrophorus SPP egg and liver oils in relation to age

The liver oil content of seven MediterraneanCentrophorus spp. were studied together with the oil of one unfertilized egg and one yolk bag. The relative weight of the liver ranges from 15 to 29% of total body weight; 63 to 89% of the liver weight is oil. Squalene, the major component (49–89% in oil) of the unsaponifiable fraction, is directly quantified by GLC following TLC separation. The squalene level increases with the age of the animals. More than 50 fatty acid species were identified. Among them, the most abundant are: 16∶0 (22–27%), 18∶1ω9 (21–36%) and 22∶6ω3 (2–18%). The level of ω3-fatty acids, essential in the fishes, shows a maximum in the egg (26%), decreases to a minimum in the young (5%) and stabilizes to an intermediate level in the adult (12%).     

长江口徐六泾河段洪季中水期悬浮泥沙沉降特性

2007年9月27日至10月5日长江口洪季中水期间,在徐六泾2号水文平台处,结合OBS3A、LISST100(B)和ADCP对该地区的悬浮泥沙在大中小三种不同潮型下进行观测.详细分析了洪季中水期该处悬浮絮凝体沉降特性,结果表明不同潮差会对絮凝体的特性产生较大的影响,在相同絮凝体粒径下,大潮差时絮凝体有效密度和沉降速度都是小潮差时絮凝体的1.5倍,整个测量期间沉降速度约为0.5～3.0mm/s.针对目前利用分形学研究泥沙沉降特性的成果结合本文结果可知徐六泾处絮凝体质量分形维数约为2.5,并且由于泥沙形状及分布不均的影响泥沙沉降特性的系数约为0.43～0.5.     

Unrestricted ramping rates and long‐term trends in the food web metrics of a boreal river

Long‐term monitoring of the food web of a regulated hydropeaking river was conducted to assess if previously documented effects of changing ramping rates (RRs) were maintained with the addition of 6 years of data. Using carbon and nitrogen stable isotope analyses, we hypothesized that: (1) macroinvertebrates and fish inhabiting areas below peaking hydrodams would be higher in δ¹⁵N and lower in δ¹³C due to increased flow velocity and the influence of light respired dissolved inorganic carbon, relative to those sampled from areas with a natural flow regime; (2) the increase in δ¹⁵N of macroinvertebrates would lead a shorter food web length in the regulated river, but δ¹³C and niche width would be similar between the restricted and unrestricted RR periods (i.e., the BACI analysis); and (3) isotopic metrics (e.g., δ¹³C, δ¹⁵N, niche width [SEA_B], and food chain length [Δ¹⁵N]) would correlate with variations in flow characteristics through time. Consistent with previous analysis conducted over a shorter time period, a shift toward higher δ¹⁵N values was observed for both fish and invertebrates, but, contrarily, only invertebrates (not fish) had a lower δ¹³C value downstream of the dam. Over the long term, the before‐after‐control‐impact analysis found no effect of RRs on any of the food web metrics, implying that the change in operation did not affect the river food web. However, analysis of the time series data indicated that flow metrics and trophic metrics were often correlated, including a negative effect of RR (invertebrates) and discharge (fish) on food chain length. This study illustrates the difficulty in detecting changes in food web structure and function under changing flow regime influenced by natural and anthropogenic effects. As such, this study highlights the need for considering large spatial and temporal scales to differentiate between confounding effects of climate, natural variability, and altered flow regimes on food webs in regulated rivers.     

Application of a computational decision model to examine acute drug effects on human risk taking.

In 3 previous experiments, high doses of alcohol, marijuana, and alprazolam acutely increased risky decision making by adult humans in a 2-choice (risky vs. nonrisky) laboratory task. In this study, a computational modeling analysis known as the expectancy valence model (J. R. Busemeyer & J. C. Stout, 2002) was applied to individual-participant data from these studies, for the highest administered dose of all 3 drugs and corresponding placebo doses, to determine changes in decision-making processes that may be uniquely engendered by each drug. The model includes 3 parameters: responsiveness to rewards and losses (valence or motivation); the rate of updating expectancies about the value of risky alternatives (learning/memory); and the consistency with which trial-by-trial choices match expected outcomes (sensitivity). Parameter estimates revealed 3 key outcomes: Alcohol increased responsiveness to risky rewards and decreased responsiveness to risky losses (motivation) but did not alter expectancy updating (learning/memory); both marijuana and alprazolam produced increases in risk taking that were related to learning/memory but not motivation; and alcohol and marijuana (but not alprazolam) produced more random response patterns that were less consistently related to expected outcomes on the 2 choices. No significant main effects of gender or dose by gender interactions were obtained, but 2 dose by gender interactions approached significance. These outcomes underscore the utility of using a computational modeling approach to deconstruct decision-making processes and thus better understand drug effects on risky decision making in humans. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of salt and smoke on the microbiological quality of cold-smoked salmon during storage at 5 degrees C as estimated by the factorial design method

The simultaneous effect of salt and smoke on the natural flora of cold-smoked salmon was studied during 5 weeks of vacuum storage at 5 degrees C. The quadratic polynomial, as a function of factors, was used to express total viable count (TVC), total lactic acid bacteria, lactobacilli numerated on Rogosa agar, H2S-producing bacteria, and yeasts at different sampling times. TVC and total lactic acid bacteria were mainly inhibited by the salt concentration (5% wt/wt) in the meat and to a lesser extent by the phenol content. Inhibition was linearly proportional to salt and smoke content (the higher the concentration, the greater the inhibition). No synergistic effect on inhibition was observed between the two factors. In our working conditions, the TVC French standard (<10(6) CFU g(-1)) was maintained during 4 weeks of storage at 5 degrees C, with a minimum concentration of 2.4% (wt/wt) of salt in meat and smoking treatment corresponding to 0.6 mg 100 g(-1) of phenol. When the salt level was higher than 3%, the TVC standard was maintained, regardless of phenol level. A negative interaction between the two factors was found for H2S-producing bacteria and a positive one for yeasts.     

Intracellular accumulation of norfloxacin in Mycobacterium smegmatis

To evaluate the intracellular accumulation of norfloxacin in mycobacteria, two methods were used with Mycobacterium smegmatis. A radiometric method (K. V. Cundy, C. E. Fasching, K. E. Willard, and L. R. Peterson, J. Antimicrob. Chemother. 28:491-497, 1991) was used without great modification, but the fluorometric method (P. G. S. Mortimer and L. J. V. Piddock, J. Antimicrob. Chemother. 28:639-653, 1991) was changed considerably. Indeed, adsorption of the quinolone to the bacterial surface was characterized by measuring the level of accumulation of 0 degree C. Taking into account the adsorption, the pH of the washing buffer was increased from 7.0 to 9.0 to improve the desorption of norfloxacin from the cell surface. Both the fluorometric method, with the technical improvement, and the radiometric method could be used to estimate the intracellular accumulation of norfloxacin, which resulted from the difference between the whole uptake measured at 37 degrees C and the adsorption measured at 0 degrees C. A total of 35 ng of norfloxacin per mg of cells (dry weight) penetrated into the M. smegmatis cell, and the steady state was achieved in 5 min. Use of inhibitors of the proton motive force revealed that transport of norfloxacin was energy independent. Thus, the same mechanisms of quinolone accumulation that occur in eubacteria seem to occur in mycobacteria, at least in M. smegmatis.     

Classement des porteurs de charge et conductivite du compose K8Na4Sb12O36 de structure KSbO3 cubique

Two structures have been reported for cubic KSbO₃ type. One has space group Pn3, where K⁺ ions are in an ordered state. The other has Im3 with K⁺ ions in a disordered state. These ions are weakly bound in large tunnels along 〈111〉 and are mobile along them three-dimensionally.The presence of two alkaline cations in these tunnels is in favour of the ordered state. Single-crystals of K₈Na₄Sb₁₂O₃₆ are obtained and crystallize in the space group Pn3, $\text{a}\text{= 9,515(3)}\text{A}\text{?}$. Using 563 independent reflections, the structure has been refined by full-matrix least squares, to factor R = 0,059.The comparison of the ionic conductivity of ordered (Pn3) and disordered (Im3) compounds is studied by the authors.     

Decision theory and artificial intelligence: I. A semantics-based region analyzer

Mathematical decision theory can be combined with heuristic techniques to attack Artificial Intelligence problems. As a first example, the problem of breaking an image into meaningful regions is considered. Bayesian decision theory is seen to provide a mechanism for including problem dependent (semantic) information in a general system. Some results are presented which make the computation feasible. A programming system based on these ideas and its application to road scenes is described.     

Reality testing by schizophrenics.

Compared 15 schizophrenics with 15 controls of similar mental test status and educational background on 2 classes of elementary problems from a series of artifact testing tasks monitored by an automatic problem programing machine called the Heuristic Evaluation Problem Programmer. In terms of an index that reflects the ability to conduct the required inquiry efficiently, the groups did not differ significantly on statistical tests that employed between-Ss differences as the error variance. Repeated measures of group differences showed a small, but statistically significant, superiority for the control Ss. Intercorrelations between scores on various problem sets indicated that the tests were reliable. During the 1st 3/4 of the problem series, there was a marked inefficiency of performance in a small group of paranoid schizophrenics as compared with a group of chronic undifferentiated schizophrenics. (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)