The Invisible Power of MacHines Revisiting the Proposed Flash Order Ban in the Wake of the Flash Crash

Technological innovation continues to make trading and markets more efficient, generally benefitting market participants and the investing public. But flash trading, a practice that evolved from high-frequency trading, benefits only a select few sophisticated traders and institutions with the resources necessary to view and respond to flashed orders. This practice undermines the basic principles of fairness and transparency in securities regulation, exacerbates information asymmetries and harms investor confidence. This iBrief revisits the Securities and Exchange Commission\u27s proposed ban on the controversial practice of flash trading and urges the Securities and Exchange Commission and the Commodity Futures Trading Commission to implement the ban across the securities and futures markets. Banning flash trading will not impact high-frequency trading or other advantageous innovative trading practices, and will benefit all market participants by making prices and liquidity more transparent. In the wake of the May 6, 2010 flash crash and the passage of the Dodd-Frank Wall Street Reform and Consumer Protection Act, now is an opportune time for the Securities and Exchange Commission and Commodity Futures Trading Commission to implement the ban

Avoiding perceived past resource use of potential competitors affects niche dynamics in a bird community

Social information use is usually considered to lead to ecological convergence among involved con- or heterospecific individuals. However, recent results demonstrate that observers can also actively avoid behaving as those individuals being observed, leading to ecological divergence. This phenomenon has been little explored so far, yet it can have significant impact on resource use, realized niches and species co-existence. In particular, the time-scale and the ecological context over which such shifts can occur are unknown. We examined with a long-term (four years) field experiment whether experimentally manipulated, species-specific, nest-site feature preferences (symbols on nest boxes) are transmitted across breeding seasons and affect future nest-site preferences in a guild of three cavity-nesting birds.</p

The past and the present in decision-making: the use of conspecific and heterospecific cues in nest site selection

Nest-site selection significantly affects fitness, so adaptations for assessment of the qualities of available sites are expected. The assessment may be based on personal or social information, social information referring to the observed location and performance of both con- and heterospecific individuals. Contrary to large-scale breeding habitat selection, small-scale nest-site selection within habitat patches is insufficiently understood. We analyzed nest-site selection in the migratory collared flycatcher Ficedula albicollis in relation to present and past cues provided by conspecifics and by resident tits within habitat patches by using long-term data. Collared flycatchers preferred nest boxes that were occupied by conspecifics in the previous year. This preference was strongest in breeding pairs where both individuals bred in the same forest patch in the previous year. The results also suggest preference for nest boxes close to boxes where conspecifics had a high breeding success in the previous year, and for nest boxes which are presently surrounded by a high number of breeding great tits Parus major. The results indicate social information use in nest-site selection at a small spatial scale, where collared flycatchers use conspecific cues with a time lag of one year and heterospecific cues instantly.</p

Use of facility assessment data to improve reproductive health service delivery in the Democratic Republic of the Congo

Background: Prolonged exposure to war has severely impacted the provision of health services in the Democratic Republic of the Congo (DRC). Health infrastructure has been destroyed, health workers have fled and government support to health care services has been made difficult by ongoing conflict. Poor reproductive health (RH) indicators illustrate the effect that the prolonged crisis in DRC has had on the on the reproductive health (RH) of Congolese women. In 2007, with support from the RAISE Initiative, the International Rescue Committee (IRC) and CARE conducted baseline assessments of public hospitals to evaluate their capacities to meet the RH needs of the local populations and to determine availability, utilization and quality of RH services including emergency obstetric care (EmOC) and family planning (FP). Methods: Data were collected from facility assessments at nine general referral hospitals in five provinces in the DRC during March, April and November 2007. Interviews, observation and clinical record review were used to assess the general infrastructure, EmOC and FP services provided, and the infection prevention environment in each of the facilities. Results: None of the nine hospitals met the criteria for classification as an EmOC facility (either basic or comprehensive). Most facilities lacked any FP services. Shortage of trained staff, essential supplies and medicines and poor infection prevention practices were consistently documented. All facilities had poor systems for routine monitoring of RH services, especially with regard to EmOC. Conclusions: Women's lives can be saved and their well-being improved with functioning RH services. As the DRC stabilizes, IRC and CARE in partnership with the local Ministry of Health and other service provision partners are improving RH services by: 1) providing necessary equipment and renovations to health facilities; 2) improving supply management systems; 3) providing comprehensive competency-based training for health providers in RH and infection prevention; 4) improving referral systems to the hospitals; 5) advocating for changes in national RH policies and protocols; and 6) providing technical assistance for monitoring and evaluation of key RH indicators. Together, these initiatives will improve the quality and accessibility of RH services in the DRC - services which are urgently needed and to which Congolese women are entitled by international human rights law

Partial Purification and Characterization of Pro-tease from Abrus precatorius Linn. (Fabaceae) from Cameroon

Abstract Crude enzyme extracts were prepared from leaves and stems of Abrus precatorius Linn. (Fabaceae) from Cameroon under optimized conditions. Proteolytic enzymes were precipitated with ammonium sulfate at 35% (w/v) saturation and assayed for enzyme activity. The effects of temperature, pH, incubation time and substrate specificity were studied. SDS-PAGE was used to determine molecular weight of precipitated protease. Results indicated that proteolytic activity of crude extract was 35.20 U/ml compared to 51.03 U/ml of partial purified extract. The optimum enzyme activity was found to be at 40˚C, while 50% of activity was maintained at 60˚C after 60 min incubation. Partial purified crude extract exhibited two optimum pH (2.75 and 9.0). The highest enzyme activity towards Bovine Serum Albumine (25.9 U/ml) was noted. SDS-PAGE gels exhibited molecular weight between 40 -60 KDa. This result confirms that partial purified extract of A. precatorius contains proteases and could be a promising source for proteolytic enzyme extraction

Maternally supplied S-acyl-transferase is required for crystalloid organelle formation and transmission of the malaria parasite.

Transmission of the malaria parasite from the mammalian host to the mosquito vector requires the formation of adequately adapted parasite forms and stage-specific organelles. Here we show that formation of the crystalloid-a unique and short-lived organelle of the Plasmodium ookinete and oocyst stage required for sporogony-is dependent on the precisely timed expression of the S-acyl-transferase DHHC10. DHHC10, translationally repressed in female Plasmodium berghei gametocytes, is activated translationally during ookinete formation, where the protein is essential for the formation of the crystalloid, the correct targeting of crystalloid-resident protein LAP2, and malaria parasite transmission

Cathepsin G activity lowers plasma LDL and reduces atherosclerosis

AbstractCathepsin G (CatG), a serine protease present in mast cells and neutrophils, can produce angiotensin-II (Ang-II) and degrade elastin. Here we demonstrate increased CatG expression in smooth muscle cells (SMCs), endothelial cells (ECs), macrophages, and T cells from human atherosclerotic lesions. In low-density lipoprotein (LDL) receptor-deficient (Ldlr–/–) mice, the absence of CatG reduces arterial wall elastin degradation and attenuates early atherosclerosis when mice consume a Western diet for 3months. When mice consume this diet for 6months, however, CatG deficiency exacerbates atherosclerosis in aortic arch without affecting lesion inflammatory cell content or extracellular matrix accumulation, but raises plasma total cholesterol and LDL levels without affecting high-density lipoprotein (HDL) or triglyceride levels. Patients with atherosclerosis also have significantly reduced plasma CatG levels that correlate inversely with total cholesterol (r=–0.535, P<0.0001) and LDL cholesterol (r=–0.559, P<0.0001), but not with HDL cholesterol (P=0.901) or triglycerides (P=0.186). Such inverse correlations with total cholesterol (r=–0.504, P<0.0001) and LDL cholesterol (r=–0.502, P<0.0001) remain significant after adjusting for lipid lowering treatments among this patient population. Human CatG degrades purified human LDL, but not HDL. This study suggests that CatG promotes early atherogenesis through its elastinolytic activity, but suppresses late progression of atherosclerosis by degrading LDL without affecting HDL or triglycerides

The glutathione biosynthetic pathway of Plasmodium is essential for mosquito transmission

1Infection of red blood cells (RBC) subjects the malaria parasite to oxidative stress. Therefore, efficient antioxidant and redox systems are required to prevent damage by reactive oxygen species. Plasmodium spp. have thioredoxin and glutathione (GSH) systems that are thought to play a major role as antioxidants during blood stage infection. In this report, we analyzed a critical component of the GSH biosynthesis pathway using reverse genetics. Plasmodium berghei parasites lacking expression of gamma-glutamylcysteine synthetase (γ-GCS), the rate limiting enzyme in de novo synthesis of GSH, were generated through targeted gene disruption thus demonstrating, quite unexpectedly, that γ-GCS is not essential for blood stage development. Despite a significant reduction in GSH levels, blood stage forms of pbggcs− parasites showed only a defect in growth as compared to wild type. In contrast, a dramatic effect on development of the parasites in the mosquito was observed. Infection of mosquitoes with pbggcs− parasites resulted in reduced numbers of stunted oocysts that did not produce sporozoites. These results have important implications for the design of drugs aiming at interfering with the GSH redox-system in blood stages and demonstrate that de novo synthesis of GSH is pivotal for development of Plasmodium in the mosquito

Deficiency and Also Transgenic Overexpression of Timp-3 Both Lead to Compromised Bone Mass and Architecture In Vivo

Tissue inhibitor of metalloproteinases-3 (TIMP-3) regulates extracellular matrix via its inhibition of matrix metalloproteinases and membrane-bound sheddases. Timp-3 is expressed at multiple sites of extensive tissue remodelling. This extends to bone where its role, however, remains largely unresolved. In this study, we have used Micro-CT to assess bone mass and architecture, histological and histochemical evaluation to characterise the skeletal phenotype of Timp-3 KO mice and have complemented this by also examining similar indices in mice harbouring a Timp-3 transgene driven via a Col-2a-driven promoter to specifically target overexpression to chondrocytes. Our data show that Timp-3 deficiency compromises tibial bone mass and structure in both cortical and trabecular compartments, with corresponding increases in osteoclasts. Transgenic overexpression also generates defects in tibial structure predominantly in the cortical bone along the entire shaft without significant increases in osteoclasts. These alterations in cortical mass significantly compromise predicted tibial load-bearing resistance to torsion in both genotypes. Neither Timp-3 KO nor transgenic mouse growth plates are significantly affected. The impact of Timp-3 deficiency and of transgenic overexpression extends to produce modification in craniofacial bones of both endochondral and intramembranous origins. These data indicate that the levels of Timp-3 are crucial in the attainment of functionally-appropriate bone mass and architecture and that this arises from chondrogenic and osteogenic lineages

Meniscal and ligament modifications in spontaneous and post-traumatic mouse models of osteoarthritis

Abstract Osteoarthritis (OA) is a whole joint disease that affects all joint tissues, with changes in the articular cartilage (AC), subchondral bone and synovium. Pathologies in menisci and ligaments, however, are rarely analysed, although both are known to play vital roles in the mechanical stability of the joint. The aim of our study was to describe the pathological changes in menisci and ligament during disease development in murine spontaneous and post-traumatic surgically-induced OA and to quantify tissue mineralisation in the joint space using µCT imaging during OA progression. Knees of Str/ort mice (spontaneous OA model; 26-40wks) and C57CBA F1 mice following destabilisation of medial meniscus (DMM) surgery (post-traumatic OA model; 8wks after DMM), were used to assess histological meniscal and ligament pathologies. Joint space mineralised tissue volume was quantified by µCT. Meniscal pathological changes in Str/ort mouse knees were associated with articular cartilage lesion severity. These meniscal changes included ossification, hyperplasia, cell hypertrophy, collagen type II deposition and SOX9 expression in the fibrous region near the attachment to the knee joint capsule. Anterior cruciate ligaments exhibited extracellular matrix changes and chondrogenesis particularly at the tibial attachment site, and ossification was seen in collateral ligaments. Similar changes were confirmed in the post-traumatic DMM model. µCT analysis showed increased joint space mineralised tissue volume with OA progression in both the post-traumatic and spontaneous OA models. Modifications in meniscal and ligament mineralisation and chondrogenesis are seen with overt AC degeneration in murine OA. Although the aetiology and the consequences of such changes remain unknown, they will influence stability and load transmission of the joint and may therefore contribute to OA progression. In addition, these changes may have important roles in movement restriction and pain, which represent major human clinical symptoms of OA. Description of such soft tissue changes, in addition to AC degradation, should be an important aspect of future studies in mouse models in order to furnish a more complete understanding of OA pathogenesis. Summary statement This manuscript describes histological changes in mouse knee joints in two models of osteoarthritis and correlates joint space mineralised tissue volume measured by µCT with disease severity