Limits on thermal variations in a dozen quiescent neutron stars over a decade

In quiescent low-mass X-ray binaries (qLMXBs) containing neutron stars, the origin of the thermal X-ray component may be either release of heat from the core of the neutron star, or continuing low-level accretion. In general, heat from the core should be stable on timescales $<10^4$ years, while continuing accretion may produce variations on a range of timescales. While some quiescent neutron stars (e.g. Cen X-4, Aql X-1) have shown variations in their thermal components on a range of timescales, several others, particularly those in globular clusters with no detectable nonthermal hard X-rays (fit with a powerlaw), have shown no measurable variations. Here, we constrain the spectral variations of 12 low mass X-ray binaries in 3 globular clusters over $\sim10$ years. We find no evidence of variations in 10 cases, with limits on temperature variations below 11% for the 7 qLMXBs without powerlaw components, and limits on variations below 20% for 3 other qLMXBs that do show non-thermal emission. However, in 2 qLMXBs showing powerlaw components in their spectra (NGC 6440 CX 1 & Terzan 5 CX 12) we find marginal evidence for a 10% decline in temperature, suggesting the presence of continuing low-level accretion. This work adds to the evidence that the thermal X-ray component in quiescent neutron stars without powerlaw components can be explained by heat deposited in the core during outbursts. Finally, we also investigate the correlation between hydrogen column density (N$_H$) and optical extinction (A$_V$) using our sample and current models of interstellar X-ray absorption, finding $N_H ({\rm cm}^{-2}) = (2.81\pm0.13)\times10^{21} A_V$.Comment: 16 pages, 5 figures, MNRAS, in pres

Soil Microbial Responses to Elevated CO2 and O3 in a Nitrogen-Aggrading Agroecosystem

Climate change factors such as elevated atmospheric carbon dioxide (CO2) and ozone (O3) can exert significant impacts on soil microbes and the ecosystem level processes they mediate. However, the underlying mechanisms by which soil microbes respond to these environmental changes remain poorly understood. The prevailing hypothesis, which states that CO2- or O3-induced changes in carbon (C) availability dominate microbial responses, is primarily based on results from nitrogen (N)-limiting forests and grasslands. It remains largely unexplored how soil microbes respond to elevated CO2 and O3 in N-rich or N-aggrading systems, which severely hinders our ability to predict the long-term soil C dynamics in agroecosystems. Using a long-term field study conducted in a no-till wheat-soybean rotation system with open-top chambers, we showed that elevated CO2 but not O3 had a potent influence on soil microbes. Elevated CO2 (1.5×ambient) significantly increased, while O3 (1.4×ambient) reduced, aboveground (and presumably belowground) plant residue C and N inputs to soil. However, only elevated CO2 significantly affected soil microbial biomass, activities (namely heterotrophic respiration) and community composition. The enhancement of microbial biomass and activities by elevated CO2 largely occurred in the third and fourth years of the experiment and coincided with increased soil N availability, likely due to CO2-stimulation of symbiotic N2 fixation in soybean. Fungal biomass and the fungi∶bacteria ratio decreased under both ambient and elevated CO2 by the third year and also coincided with increased soil N availability; but they were significantly higher under elevated than ambient CO2. These results suggest that more attention should be directed towards assessing the impact of N availability on microbial activities and decomposition in projections of soil organic C balance in N-rich systems under future CO2 scenarios

Wyzwania poprawy mobilności miejskiej w Indiach

The urban mobility scenario in most Indian cities has deteriorated considerably in the last decade wreaking a havoc on millions of daily commuters. Lack of an integrated multimodal public transport has added to the woes of public, forced into using their cars and two wheelers for travel. This has led to an unprecedented rise in vehicular traffic and serious road congestion. This article explores the feasibility of various alternatives implemented and adopted in Delhi and its results shared for a feedback of various stakeholders. A large number of engineering associations like IRC, IRF, CEAI, IAStructE and WISE have been proactively helping the authorities in taking up technically appropriate solutions and engineering in order to improve mobility.Warunki mobilności w wiekszości miastach indyjskich pogorszyły się znacznie w ciągu ostatniej dekady, utrudniając życie milionom ludzi dojeżdżającym codzienne do pracy. Brak zintegrowanego multimodalnego transportu publicznego wyrażana jest społeczności miast, zmuszonej do korzystania z samochodów i jednośladów w codziennej podróży. Doprowadziło to do bezprecedensowego wzrosut ruchu kołowego i niebywałego natężenia ruchu drogowego. Niniejsza praca poświęcona jest omówieniu studium wykonalności różnych alternatyw rozwiązań wypróbowanych i przyjętych w Delhi, których wyniki udostępniono dla opinii różnych zainteresowanych stron, w tym organizacjom NGO i stowarzyszeniom. Wiele stowarzyszeńi inżynierskich, takich jak IRC, IRF, CEAI, IAStructE, zostało aktywnie zaangażowane w doradztwo i pomoc władzom w podejmowaniu odpowiednich rozwiązań technicznych i inżynierskich w kierunku poprawy mobilności

An inter-institutional collaborative project: The why, the what and the how.

This seminar will start by outlining the OPTIMUS Pro-ject, the overarching goal of which is to produce an online resource for the use of Hong Kong tertiary level students to improve their English speaking skills. This large, Inter-institutional, UGC-funded project is im-portant because students need to orally present them-selves and their work both in the university and later in the professional world. At the heart of the project is a corpus of authentic video exemplars of best-practice speaking from expert and peer presenters. The user in-terface provides multiple points of access and pathways through the corpus and supplements it with learner-friendly support. In this seminar we will give an over-view of the project and discuss briefly the logistical oper-ations of such a large project. We will then demonstrate the user interface and discuss the potential for teaching and learning applications of the project

The kinetics of NH4 + and NO3 − uptake by Douglas fir from single N-solutions and from solutions containing both NH4 + and NO3 −

The kinetics of NH4+ and NO3- uptake in young Douglas fir trees (Pseudotsuga menziesii [Mirb.] Franco) were studied in solutions, containing either one or both N species. Using solutions containing a single N species, the V(max) of NH4+ uptake was higher than that of NO3- uptake. The K(m) of NH4+ uptake and K(m) of NO3- uptake differed not significantly. When both NH4+ and NO3- were present, the V(max) for NH4+ uptake became slightly higher, and the K(m) for NH4+ uptake remained in the same order. Under these conditions the NO3- uptake was almost totally inhibited over the whole range of concentrations used (10-1000 muM total N). This inhibition by NH4+ occurred during the first two hours after addition

A comparison of English and Chinese reading proficiency of primary school Chinese students

Hong Kong children's comprehension of Chinese and English text is of concern to parents and teachers since school leavers need to be proficient readers both of Chinese and English. Although Chinese has been officially designated the medium of instruction in most secondary schools, many parents want their children to be taught in English-medium schools for, although Hong Kong is now a Chinese region, being literate in English is still highly prized by the public. A comparison was made of the bilingual reading attainment of Hong Kong primary students, using instruments and procedures used in the 2001 Progress in International Reading Literacy Study. The average standard of reading English was below the international average, and only 70% of the average standard of reading in Chinese. Only 7% of students read English as well as age-related peers in English-speaking countries. Whereas this minority can be taught via English to no academic detriment, most students understand text much less well in English than in Chinese. The best readers were good both in English and Chinese, the poor readers being particularly weak readers of English. Being taught via English enhanced students' general English reading ability, and being taught in Cantonese enhanced their Chinese reading ability. © 2010 Taylor & Francis.link_to_subscribed_fulltex