A Note on the Intensity of Downside Risk Aversion

In this note we show that the measure of intensity of downside risk aversion proposed recently by Crainich and Eeckhoudt (2007) cannot be guaranteed to exist. We do this by means of an example in which the existence of the measure depends upon the values of the parameters in the problem.risk aversion, prudence, downside risk

Tax Effort: The Impact of Corruption, Voice and Accountability

In this paper we argue that a more legitimate and responsive state is an essential factor for a more adequate level of tax effort in developing countries. While at first glance giving such advice to poor countries seeking to increase their tax ratios may not seem more helpful than telling them to find oil, it is presumably more feasible for people to improve their governing institutions than to rearrange nature’s bounty. Improving corruption, voice and accountability may not take longer nor be necessarily more difficult than changing the opportunities for tax handles and economic structure. The key contribution of this paper is to extend the conventional model of tax effort by showing that not only do supply factors matter, but that demand factors such as corruption, voice and accountability also determine tax effort to a significant extent.Tax effort, tax reforms, developing countries, Latin America, corruption, voice and accountability.

Roles of transcriptional and translational control mechanisms in regulation of ribosomal protein synthesis in Escherichia coli

ABSTRACTBacterial ribosome biogenesis is tightly regulated to match nutritional conditions and to prevent formation of defective ribosomal particles. InEscherichia coli, most ribosomal protein (r-protein) synthesis is coordinated with rRNA synthesis by a translational feedback mechanism: when r-proteins exceed rRNAs, specific r-proteins bind to their own mRNAs and inhibit expression of the operon. It was recently discovered that the second messenger nucleotide guanosine tetra and pentaphosphate (ppGpp), which directly regulates rRNA promoters, is also capable of regulating many r-protein promoters. To examine the relative contributions of the translational and transcriptional control mechanisms to the regulation of r-protein synthesis, we devised a reporter system that enabled us to genetically separate thecis-acting sequences responsible for the two mechanisms and to quantify their relative contributions to regulation under the same conditions. We show that the synthesis of r-proteins from the S20 and S10 operons is regulated by ppGpp following shifts in nutritional conditions, but most of the effect of ppGpp required the 5′ region of the r-protein mRNA containing the target site for translational feedback regulation and not the promoter. These results suggest that most regulation of the S20 and S10 operons by ppGpp following nutritional shifts is indirect and occurs in response to changes in rRNA synthesis. In contrast, we found that the promoters for the S20 operon were regulated during outgrowth, likely in response to increasing nucleoside triphosphate (NTP) levels. Thus, r-protein synthesis is dynamic, with different mechanisms acting at different times.IMPORTANCEBacterial cells have evolved complex and seemingly redundant strategies to regulate many high-energy-consuming processes. InE. coli, synthesis of ribosomal components is tightly regulated with respect to nutritional conditions by mechanisms that act at both the transcription and translation steps. In this work, we conclude that NTP and ppGpp concentrations can regulate synthesis of ribosomal proteins, but most of the effect of ppGpp is indirect as a consequence of translational feedback in response to changes in rRNA levels. Our results illustrate how effects of seemingly redundant regulatory mechanisms can be separated in time and that even when multiple mechanisms act concurrently their contributions are not necessarily equivalent.</jats:p

Tax Effort in Developing Countries and High Income Countries: The Impact of Corruption, Voice and Accountability

In this paper we argue that a more legitimate and responsive state is an essential factor for a more adequate level of tax effort in developing countries and high income countries. While at first glance giving such advice to poor countries seeking to increase their tax ratios may not seem more helpful than telling them to find oil, it is presumably more feasible for people to improve their governing institutions than to rearrange nature’s bounty. Improving corruption, voice and accountability may not take longer nor be necessarily more difficult than changing the opportunities for tax handles and economic structure. The paper also shows that high income countries have also the potential of improving their tax performance through improving their institutions. The key contribution of this paper is to extend the conventional model of tax effort by showing that not only do supply factors matter, but that demand factors such as corruption, voice and accountability also determine tax effort to a significant extent

Benchmarking Tax Administrations in Developing Countries: A Systemic Approach

Benchmarking as a way of establishing standards for evaluating the performance of tax administrations has become increasingly popular in recent years. Two common approaches to benchmarking are ‘benchmarking by numbers’ – the quantitative approach and ‘benchmarking by (presumed) good institutional practice’ – the qualitative approach. Both these approaches consider each component or aspect of the tax administration separately. This paper suggests a contrasting approach to benchmarking, the purpose of which is less to allow others to assess the performance of a tax administration than it is to permit an administration to understand and improve its own performance. This systemic approach is more conceptually and operationally difficult because it requires considering how all aspects of the administrative system function as a whole in the context of the environment within which that system is embedded and operates. On the other hand, it is also more directly aimed at understanding and improving the key operational strategies that define good, better and best tax administrations

Migration and Invasion of Brain Tumors

Recent advances in molecular biology have led to new insights in the development, growth and infiltrative behaviors of primary brain tumors (Demuth and Berens, 2004; Huse and Holland, 2010; Johnson et al., 2009; Kanu et al., 2009). These tumors are derived from various brain cell lineages and have been historically classified on the basis of morphological and, more recently, immunohistochemical features with less emphasis on their underlying molecular pathogenesis (Huse and Holland, 2010). The detailed molecular characterization of brain tumors has laid the groundwork for augmentation of standard treatment with patient-specific designed targeted therapies (Johnson et al., 2009; Kanu et al., 2009). Nevertheless, these tumors are extremely aggressive in their infiltration of brain tissue (Altman et al., 2007; Hensel et al., 1998; Yamahara et al., 2010), as well as in their metastasis outside of brain (Algra et al., 1992). Further, it now appears that the physiological conditions of the normal brain itself constitute a biological environment conducive to the uncontrolled dissemination of primary tumors (Bellail et al., 2004; Sontheimer, 2004). This review surveys the latest research on the invasive behavior of two major types of primary brain tumors: gliomas and medulloblastomas - the most common tumors diagnosed within adult and pediatric brain, respectively (Rickert and Paulus, 2001). The material has been divided into five sections: i) Characteristics of malignant brain tumors; ii) Mechanisms of tumor cell migration; iii) Models for the study of brain tumor invasion in vivo and ex vivo; iv) Models for the study of brain tumor invasion in vitro; and v) Future prospects of anti-invasive brain tumor therapy

Comparison of three reproductive management strategies for lactating dairy cows using detection of oestrus or synchronisation of ovulation and Fixed-Timed Artificial Insemination

The most common dairy cattle reproductive management strategies combine oestrus detection with hormonal protocols for synchronisation of ovulation for breeding. However, approximately 50% of oestrus cycles are missed in commercial dairy farms due to human error and poor expression of oestrus behaviour. Furthermore, around 20% of cows experience prolonged postpartum anovulation. Synchronisation protocols may have variable synchronisation rates, producing suboptimal pregnancies per artificial insemination (P/AI). The aim of this study was to compare the reproductive performance of three commercial reproductive management strategies in lactating dairy cows: a combination of oestrus detection (OD) followed by ovulation synchronisation protocol for fixed timed artificial insemination (FTAI) either using Ovsynch or PRID-synch, or Double Ovsynch at FTAI. Cows (n = 1681) were randomly assigned to one of three different reproductive strategies at calving: Oestrus detection - Ovsynch (OD-Ov), Oestrus detection - PRIDsynch (OD-PR) and Double Ovsynch (DO). Cows enrolled in OD-Ov, and OD-PR were eligible to be inseminated after observed oestrus between 50 and 70±3 days in milk (DIM). Cows in which oestrus was not detected between 50 and 70±3 DIM (OD-Ov, n = 541; OD-PR, n = 562) received their respective hormonal treatments at 70±3 DIM. In these two groups, cows that returned to oestrus within the period for first FTAI (<83DIM) had more than one opportunity for AI. Cows enrolled in DO were subjected to FTAI only. Postpartum disorders were recorded between 1 and 7 DIM; and lameness, mastitis and bovine respiratory disease were recorded until first AI. Body condition score (BCS) was recoded at calving, 43±3 and 70±3 DIM. Ovarian monitoring was performed by transrectal ultrasonography (US) at 43±3 and 50±3 DIM, and at 70±3 and 77±3 DIM only for synchronised cows. Effects of treatments were assessed with multivariable statistical methods relevant for each outcome variable. Pregnancy 32±3 d after first AI was similar among treatment groups (OD-Ov = 43.2%, ODPR = 41.6%; DO = 45.7%) and proportion of cows pregnant by 83 DIM was also similar among treatment groups (OD-Ov = 46.5%, OD-PR = 46.6%; DO = 45.7%). Farm, parity, BCS at 43±3 DIM and breeding sire were associated with reproductive performance. Pregnancy loss (PL) was significantly higher in the OD-Ov (9.7%) than in the OD-PR (4.1%). In conclusion, no difference in reproductive performance among reproductive strategies was observed in this study, suggesting that reproductive performance is influenced by farm-specific factors such as oestrus detection rate and P/AI, and overall cow health

TIME DILATION CONTROLS FOR CAMERAS

A computing device (e.g., a mobile phone, camera, tablet computer, etc.) may include a camera for capturing/recording video and may present a user interface at a display device (e.g., a presence-sensitive screen) from which a user can interact with the camera of the computing device to change or adjust time dilation effects (making a video record such that it plays faster than it actually occurred, or to record a video that will play slower than it occurred). For example, the user interface may provide a selector to adjusting a playback rate of captured video and a selector for adjusting a time dilation multiplier. When capturing video, the user interface may provide an indicator that shows the recording duration, and the playback duration of the video. This way, a computing device may provide a user with a concise way of controlling and visualizing time dilation effects