Finite pp-groups with a minimal non-abelian subgroup of index pp (IV)

In this paper, we completely classify the finite $p$-groups $G$ such that $\Phi(G')G_3\le C_p^2$, $\Phi(G')G_3\le Z(G)$ and $G/\Phi(G')G_3$ is minimal non-abelian. This paper is a part of the classification of finite $p$-groups with a minimal non-abelian subgroup of index $p$. Together with other four papers, we solve a problem proposed by Y. Berkovich

Pedestrian dynamics in single-file movement of crowd with different age compositions

An aging population is bringing new challenges to the management of escape routes and facility design in many countries. This paper investigates pedestrian movement properties of crowd with different age compositions. Three pedestrian groups are considered: young student group, old people group and mixed group. It is found that traffic jams occur more frequently in mixed group due to the great differences of mobilities and self-adaptive abilities among pedestrians. The jams propagate backward with a velocity 0.4 m/s for global density around 1.75 m-1 and 0.3 m/s for higher than 2.3 m-1. The fundamental diagrams of the three groups are obviously different from each other and cannot be unified into one diagram by direct non-dimensionalization. Unlike previous studies, three linear regimes in mixed group but only two regimes in young student group are observed in the headway-velocity relation, which is also verified in the fundamental diagram. Different ages and mobilities of pedestrians in a crowd cause the heterogeneity of system and influence the properties of pedestrian dynamics significantly. It indicates that the density is not the only factor leading to jams in pedestrian traffic. The composition of crowd has to be considered in understanding pedestrian dynamics and facility design.Comment: 11 pages, 13 figures, 3 table

Antibiotic resistance as a global threat: Evidence from China, Kuwait and the United States

BACKGROUND: Antimicrobial resistance is an under-appreciated threat to public health in nations around the globe. With globalization booming, it is important to understand international patterns of resistance. If countries already experience similar patterns of resistance, it may be too late to worry about international spread. If large countries or groups of countries that are likely to leap ahead in their integration with the rest of the world – China being the standout case – have high and distinctive patterns of resistance, then a coordinated response could substantially help to control the spread of resistance. The literature to date provides only limited evidence on these issues. METHODS: We study the recent patterns of antibiotic resistance in three geographically separated, and culturally and economically distinct countries – China, Kuwait and the United States – to gauge the range and depth of this global health threat, and its potential for growth as globalization expands. Our primary measures are the prevalence of resistance of specific bacteria to specific antibiotics. We also propose and illustrate methods for aggregating specific "bug-drug" data. We use these aggregate measures to summarize the resistance pattern for each country and to study the extent of correlation between countries' patterns of drug resistance. RESULTS: We find that China has the highest level of antibiotic resistance, followed by Kuwait and the U.S. In a study of resistance patterns of several most common bacteria in China in 1999 and 2001, the mean prevalence of resistance among hospital-acquired infections was as high as 41% (with a range from 23% to 77%) and that among community- acquired infections was 26% (with a range from 15% to 39%). China also has the most rapid growth rate of resistance (22% average growth in a study spanning 1994 to 2000). Kuwait is second (17% average growth in a period from 1999 to 2003), and the U.S. the lowest (6% from 1999 to 2002). Patterns of resistance across the three countries are not highly correlated; the most correlated were China and Kuwait, followed by Kuwait and the U.S., and the least correlated pair was China and the U.S. CONCLUSION: Antimicrobial resistance is a serious and growing problem in all three countries. To date, there is not strong international convergence in the countries' resistance patterns. This finding may change with the greater international travel that will accompany globalization. Future research on the determinants of drug resistance patterns, and their international convergence or divergence, should be a priority

Gene-to-metabolite network for biosynthesis of lignans in MeJA-elicited Isatis indigotica hairy root cultures.

Root and leaf tissue of Isatis indigotica shows notable anti-viral efficacy, and are widely used as "Banlangen" and "Daqingye" in traditional Chinese medicine. The plants' pharmacological activity is attributed to phenylpropanoids, especially a group of lignan metabolites. However, the biosynthesis of lignans in I. indigotica remains opaque. This study describes the discovery and analysis of biosynthetic genes and AP2/ERF-type transcription factors involved in lignan biosynthesis in I. indigotica. MeJA treatment revealed differential expression of three genes involved in phenylpropanoid backbone biosynthesis (IiPAL, IiC4H, Ii4CL), five genes involved in lignan biosynthesis (IiCAD, IiC3H, IiCCR, IiDIR, and IiPLR), and 112 putative AP2/ERF transcription factors. In addition, four intermediates of lariciresinol biosynthesis were found to be induced. Based on these results, a canonical correlation analysis using Pearson's correlation coefficient was performed to construct gene-to-metabolite networks and identify putative key genes and rate-limiting reactions in lignan biosynthesis. Over-expression of IiC3H, identified as a key pathway gene, was used for metabolic engineering of I. indigotica hairy roots, and resulted in an increase in lariciresinol production. These findings illustrate the utility of canonical correlation analysis for the discovery and metabolic engineering of key metabolic genes in plants

Implementation of quantum synchronization over a 20-km fiber distance based on frequency-correlated photon pairs and HOM interference

The quantum synchronization based on frequency-correlated photon pairs and HOM interference has shown femtosecond-level precision and great application prospect in numerous fields depending on high-precision timefrequency signals. Due to the difficulty of achieving stable HOM interference fringe after long-distance fiber transmission, this quantum synchronization is hampered from long-haul field application. Utilizing segmented fibers instead of a single long-length fiber, we successfully achieved the stable observation of the two-photon interference of the lab-developed broadband frequency-correlated photon pairs after 20 km-long fiber transmission, without employing auxiliary phase stabilization method. Referenced to this interference fringe, the balance of the two fiber arms is successfully achieved with a long-term stability of 20 fs. The HOM-interference-based synchronization over a 20-km fiber link is thus demonstrated and a minimum stability of 74 fs has been reached at 48,000 s. This result not only provides a simple way to stabilize the fiber-optic two-photon interferometer for long-distance quantum communication systems, but also makes a great stride forward in extending the quantum-interference-based synchronization scheme to the long-haul field applications.Comment: 5 pages, 4 figure

Respuesta de la actividad enzimática digestiva al incremento gradual de la salinidad en el cangrejo de Shanghai maduro, Eriocheir sinensis (Decapoda: Brachyura)

Mature Chinese mitten crabs, Eriocheir sinensis, were exposed to brackish water or seawater as an obligatory part of their reproductive migration. Physiological and biochemical reorganization were needed to adapt them to this migration. To understand the digestive adjustments of Eriocheir sinensis at biochemical level during this transformation from freshwater to seawater, the response of the activity of five digestive enzymes (amylase, cellulase, pepsin, trypsin and lipase) in the hepatopancreas to salinities increasing gradually from 0 (freshwater) to 35 (seawater) was analysed in mature females and males. Digestive enzymes exhibited significantly higher activities in the hepatopancreas of males than those of females, except lipase. In females, amylase, pepsin and trypsin activities began to decrease significantly as the salinity reached 28, and cellulase activity decreased at 35; in males, a considerable decrease in the activity of digestive enzymes, except lipase, was observed at 21 and higher salinities, while an increase was observed at 14. Reduced enzyme activities at elevated salinities suggest that the digestive capacity of crabs for diets becomes weak, and all these digestive enzymes participated in digestive adjustments during osmoregulation. The initial salinity which induced the decrease of enzyme activity was lower in males than in females, indicating that females were more tolerant to elevated salinities than males from the point of digestive biochemical modulation.Se expusieron cangrejos de Shanghai maduros (Eriocheir sinensis) a agua salobre o agua marina obligatoriamente durante la migración reproductora. A fin de que los ejemplares se adaptaran a esta migración, fue preciso proceder a una reorganización fisiológica y bioquímica. Con objeto de estudiar los ajustes digestivos de carácter bioquímico del Eriocheir sinensisdurante la transformación del agua dulce en agua marina, se analizó la reacción de la actividad en el hepatopáncreas de cinco enzimas digestivas (amilasa, celulasa, pepsina, tripsina y lipasa) a un aumento gradual de la salinidad, desde 0 ppt (agua dulce) hasta 35 ppt (agua marina), en ejemplares maduros machos y hembras. Las enzimas digestivas mostraron un grado de actividad notablemente mayor en el hepatopáncreas de los machos que en el de las hembras, con excepción de la lipasa. En las hembras, la actividad de la amilasa, la pepsina y la tripsina comenzó a reducirse notablemente cuando la salinidad alcanzó las 28 ppt, mientras que la actividad de la celulasa descendió cuando se alcanzaron las 35 ppt; en el caso de los machos, se observó un descenso muy pronunciado de la actividad enzimática digestiva a partir de las 21 ppt, aunque la actividad aumentó a las 14 ppt. La menor actividad enzimática indicaría que la capacidad digestiva de los cangrejos se reduce a niveles elevados de salinidad y que todas estas enzimas digestivas participan en los ajustes digestivos que se producen durante la osmorregulación. El nivel de salinidad inicial que indujo el descenso de la actividad enzimática fue inferior en los machos que en las hembras, lo cual indica que estas últimas mostraron una mayor tolerancia a un nivel elevado de salinidad que los machos desde el punto de vista de la modulación bioquímica del proceso digestivo