Increasing United States Investment in Foreign Securities: An Evaluation of SEC Rule 144A

The dimension of a poset $P$ is the minimum number of total orders whose intersection is $P$. We prove that the dimension of every poset whose comparability graph has maximum degree $\Delta$ is at most $\Delta \log ^{1+o(1)} \Delta$. This result improves on a 30-year old bound of Füredi and Kahn and is within a $\log ^{o(1)}\Delta$ factor of optimal. We prove this result via the notion of boxicity. The boxicity of a graph $G$ is the minimum integer $d$ such that $G$ is the intersection graph of $d$-dimensional axis-aligned boxes. We prove that every graph with maximum degree $\Delta$ has boxicity at most $\Delta \log ^{1+o(1)} \Delta$, which is also within a $\log ^{o(1)}\Delta$ factor of optimal. We also show that the maximum boxicity of graphs with Euler genus $g$ is $\Theta (\sqrt {g \log g})$, which solves an open problem of Esperet and Joret and is tight up to a constant factor

Food Security as Correlate of Interstate Conflict: A Case Study of the State of Qatar

The literature indicates that conflict can result in food insecurity due to economic or political crisis However few studies have investigated the effects that nonviolent interstate conflict has on food security in the Middle East Evidence from this study based in Qatar indicates that conflict can result in food insecurity due to economic or political crisis This research critically examines the lingering political and economic blockade of the State of Qatar and the extent to which this blockade has impacted food security of residents The study employed a sequential mixed methods approach to gain better insight into the nature of food security in Qatar A focused qualitative review of the relevant literature was followed by a quantitative analysis which revealed that there was no significant effect of interstate conflict on food security while the economic and political blockade correlated significantly with food security Three groups were sampled including government officials regulatory agencies and food supplier

Modelling Governance Indicators and Managing e-Business Information Systems

Information Systems are in growing demand in various business and government organizations. Despite increased competition, business growth and technology innovation, at times, we overlook the governance, transparency, integrity and business ethics, with the result, the quality of deliverable products and services is compromised. Several external factors such as corruption, ineffective governance, political instability, flawed regulations and violation of rules of law, unaccountability affect the connectivity between outside influences and technology implementations. To summarize, weak governance practices and unjustified business ethics are impediments to business IS implementations. Appropriate technological innovations and remedial measures are needed that can substantiate our adaptation and implementation measures. The challenges are examined in the form of a three-tiered technology development motivation, which consists of mitigation, adaptation and implementation actions. We explore the relevant issues and challenges, and the need for a holistic IS research approach with follow-up technological remedies and accountability of results in the affected geographies and demography. The purpose of the research is to build IS artefacts to link governance attributes with the lapses existing between information management, organization strategies and e-business needs. An integrated IS architecture is proposed to explore the congruence between governance indicators and e-business IS requirements. The study further explores the wide-ranging of governance indicators that affected the business IS development and implementation. Cognizance of governance facts and their modelling in e-business contexts are pathways to instigate business IS artefacts and manage their needs in industry scenarios. Based on empirical research done on attribute modelling for 200 governments worldwide, we articulate our research findings with a claim that the e-business objectives are accomplishable through successful implementation of IS architectures in industrial environments through improved governance and transparency. Various IS strategies emerge to rescue the business and organization openness and transparency. Mitigation and critical interrogation of governance indicators facilitate us understand the research phenomena and adaptation of IS artefacts that accustomed to e-business change management. Models describing affected governments, documentation in the form of multidimensional repositories, with sustainability-manifested management and accounting are the outcomes of the research. Implementation of articulated IS architecture, and its adaptations by business and government organizations ensure us smart and sustainable e-business solutions in place, operationalizing governance policies, as adhered by various stakeholders. The research offers sustainable IS artefacts and online services to multiple government organizations and businesses. The benefits of the research are multifold, and they are improved internal operations and delivery of quality public services through established electronic services. Reduced waiting times, raising transparency, reinforcing equalities, and smoothening of the overall functioning of the organizations are added benefits of the study. Cost savings, improved communications, and increased government accountability are other gains of the study

Islands of conformational stability for Filopodia

Filopodia are long, thin protrusions formed when bundles of fibers grow outwardly from a cell surface while remaining closed in a membrane tube. We study the subtle issue of the mechanical stability of such filopodia and how this depends on the deformation of the membrane that arises when the fiber bundle adopts a helical configuration. We calculate the ground state conformation of such filopodia, taking into account the steric interaction between the membrane and the enclosed semiflexible fiber bundle. For typical filopodia we find that a minimum number of fibers is required for filopodium stability. Our calculation elucidates how experimentally observed filopodia can obviate the classical Euler buckling condition and remain stable up to several tens of . We briefly discuss how experimental observation of the results obtained in this work for the helical-like deformations of enclosing membrane tubes in filopodia could possibly be observed in the acrosomal reactions of the sea cucumber Thyone, and the horseshoe crab Limulus. Any realistic future theories for filopodium stability are likely to rely on an accurate treatment of such steric effects, as analysed in this work

Laser-wakefield accelerators as hard x-ray sources for 3D medical imaging of human bone

A bright μm-sized source of hard synchrotron x-rays (critical energy Ecrit > 30 keV) based on the betatron oscillations of laser wakefield accelerated electrons has been developed. The potential of this source for medical imaging was demonstrated by performing micro-computed tomography of a human femoral trabecular bone sample, allowing full 3D reconstruction to a resolution below 50 μm. The use of a 1 cm long wakefield accelerator means that the length of the beamline (excluding the laser) is dominated by the x-ray imaging distances rather than the electron acceleration distances. The source possesses high peak brightness, which allows each image to be recorded with a single exposure and reduces the time required for a full tomographic scan. These properties make this an interesting laboratory source for many tomographic imaging applications

Angular needle tracker and stabilizer for image-guided interventions

Introduction Minimally invasive image-guided interventions have changed the face of procedural medicine. For these procedures, safety and efficacy depend on precise needle placement. Needle targeting devices help improve the accuracy of needle placement, but their use has not seen broad penetration. Some of these devices are costly and require major modifications to the clinical workflow. In this article, we developed a low-cost, disposable, and easy-to-use angulation tracking device, which was based on a redesigned commercial passive needle holder. Material and methods The new design provided real-time angulation information for needle tracking. In this design, two potentiometers were used as angulation sensors, and they were connected to two axes of the passive needle holder’s arch structure through a 3 D-printed bridge structure. A control unit included an Arduino Pro Mini, a Bluetooth module, and two rechargeable batteries. The angulation was calculated and communicated in real time to a novel developed smartphone app, where real-time angulation information was displayed for guiding the operator to position the needle to the planned angles. Results The open-air test results showed that the average errors are 1.03° and 1.08° for left–right angulation and head–foot angulation, respectively. The animal cadaver tests revealed that the novel system had an average angular error of 3.2° and a radial distance error of 3.1 mm. Conclusions The accuracy was comparable with some commercially available solutions. The novel and low-cost needle tracking device may find a role as part of a real-time precision approach to both planning and implementation of image-guided therapies