Understanding the Accrual Anomaly

Interpreting accruals as working capital investment, we hypothesize that firms rationally adjust their investment to respond to discount rate changes. Consistent with the optimal investment hypothesis, we document that (i) the predictive power of accruals for future stock returns increases with the covariations of accruals with past and current stock returns, and (ii) adding investment- based factors into standard factor regressions substantially reduces the magnitude of the accrual anomaly. High accrual firms also have similar corporate governance and entrenchment indexes as low accrual firms. This evidence suggests that the accrual anomaly is more likely to be driven by optimal investment than by investor overreaction to excessive growth or over-investment.

The Changing Landscape of Accrual Accounting

A fundamental property of accrual accounting is to smooth temporary timing fluctuations in operating cash flows, indicating an inherent negative correlation between accruals and cash flows. We show that the overall correlation between accruals and cash flows has dramatically declined in magnitude over the past half century and has largely disappeared in more recent years. The adjusted R 2 from regressing (changes in) accruals on (changes in) cash flows drops from about 70% (90%) in the 1960s to near zero (under 20%) in more recent years. In exploring potential reasons for the observed attenuation, we find that increases in non-timing-related accrual recognition, as proxied by one-time and nonoperating items and the frequency of loss firm-years, explain the majority of the overall decline. On the other hand, temporal changes in the matching between revenues and expenses, and the growth of intangible-intensive industries play only a limited role in explaining the observed attenuation. Finally, the relative decline of the timing role of accruals does not appear to be associated with an increase in the asymmetrically timely loss recognition role

Effect of nitrogen fertilization on net nitrogen mineralization in grassland soil of Northern China: implications for grassland management

Nitrogen (N) applications can have a significant effect on soil N availability. The effect of 3 years of N fertilization on soil net N mineralization during the growing season (May–September) was studied in 2005 and 2006 in grassland of northern China. The experimental design was a randomized complete block with four replications of five rates of N addition as urea (0, 2, 4, 8 and 16 g N m−2 year−1). Results indicated that net N mineralization rate varied seasonally and between years, ranging from −0.04 to 0.52 μg g−1 d−1 in 2005 and from −0.09 to 0.39 μg g−1 d−1 in 2006. Mean N mineralization and nitrification rates were highest in July, in 2005 and 2006, whereas highest ammonification rates occurred in September. Rainfall was significantly correlated with net nitrification. In comparison with the untreated control, N mineralization increased sharply when N fertilization increased from 2 to 8 g N m−2 year−1. Mobile soil NO3− accumulated late in the growing season for the 16 g N m−2 year−1 treatment, suggesting the potential for NO3 and associated cation leaching. These results suggest that N fertilization of 8 g N m−2 year−1 (80 kg N ha−1) is suitable for the management of grassland ecosystems of Inner Mongolia

ODH @ CNTs – Metal-free Catalytic Alkane Activation

The conversion of alkanes into higher valued olefins by oxidative dehydrogenation (ODH) using supported transition metal oxides is a topic of intense research, however, the yield of alkenes is still too low for industrial application. A completely innovative approach is the metal-free carbon mediated ODH catalysis, which is so far predominantly investigated on the substrate ethylbenzene. After surface modification, commercial multiwalled carbon nano-tubes (CNTs) can be used as stable catalysts also for the activation of alkanes (C2–C4), en-abling alkene yields comparable with supported vanadia catalysts but avoiding the use of toxic transition metal oxides

The sigma factor σ54 is required for the long-term survival of Leptospira biflexa in water

Leptospira spp. comprise both pathogenic and free-living saprophytic species. Little is known about the environmental adaptation and survival mechanisms of Leptospira. Alternative sigma factor, σ54 (RpoN) is known to play an important role in environmental and host adaptation in many bacteria. In this study, we constructed an rpoN mutant by allele exchange, and the complemented strain in saprophytic L. biflexa. Transcriptome analysis revealed that expression of several genes involved in nitrogen uptake and metabolism, including amtB1, glnB-amtB2, ntrX and narK, were controlled by σ54 . While wild-type L. biflexa could not grow under nitrogen-limiting conditions but was able to survive under such conditions and recover rapidly, the rpoN mutant was not. The rpoN mutant also had dramatically reduced ability to survive long-term in water. σ54 appears to regulate expression of amtB1, glnK-amtB2, ntrX and narK in an indirect manner. However, we identified a novel nitrogen-related gene, LEPBI_I1011, whose expression was directly under the control of σ54 (herein renamed as rcfA for RpoN-controlled factor A). Taken together, our data reveal that the σ54 regulatory network plays an important role in the long-term environmental survival of Leptospira spp

LtpA, a CdnL-type CarD regulator, is important for the enzootic cycle of the Lyme disease pathogen

Little is known about how Borrelia burgdorferi, the Lyme disease pathogen, adapts and survives in the tick vector. We previously identified a bacterial CarD N-terminal-like (CdnL) protein, LtpA (BB0355), in B. burgdorferi that is preferably expressed at lower temperatures, which is a surrogate condition mimicking the tick portion of the enzootic cycle of B. burgdorferi. CdnL-family proteins, an emerging class of bacterial RNAP-interacting transcription factors, are essential for the viability of Mycobacterium tuberculosis and Myxococcus xanthus. Previous attempts to inactivate ltpA in B. burgdorferi have not been successful. In this study, we report the construction of a ltpA mutant in the infectious strain of B. burgdorferi, strain B31-5A4NP1. Unlike CdnL in M. tuberculosis and M. xanthus, LtpA is dispensable for the viability of B. burgdorferi. However, the ltpA mutant exhibits a reduced growth rate and a cold-sensitive phenotype. We demonstrate that LtpA positively regulates 16S rRNA expression, which contributes to the growth defects in the ltpA mutant. The ltpA mutant remains capable of infecting mice, albeit with delayed infection. Additionally, the ltpA mutant produces markedly reduced spirochetal loads in ticks and was not able to infect mice via tick infection. Overall, LtpA represents a novel regulator in the CdnL family that has an important role in the enzootic cycle of B. burgdorferi