Velocity fluctuations and population distribution in clusters of settling particles at low Reynolds number

A study on the spatial organization and velocity fluctuations of non Brownian spherical particles settling at low Reynolds number in a vertical Hele-Shaw cell is reported. The particle volume fraction ranged from 0.005 to 0.05, while the distance between cell plates ranged from 5 to 15 times the particle radius. Particle tracking revealed that particles were not uniformly distributed in space but assembled in transient settling clusters. The population distribution of these clusters followed an exponential law. The measured velocity fluctuations are in agreement with that predicted theoretically for spherical clusters, from the balance between the apparent weight and the drag force. This result suggests that particle clustering, more than a spatial distribution of particles derived from random and independent events, is at the origin of the velocity fluctuations.Comment: 13 pages, 8 figure

A Broad View of Macroeconomic Stability

This broad view of macroeconomic stability should lead to the recognition of the role played by two sets of policy packages, whose relative importance will vary depending on the structural characteristics, the macroeconomic policy tradition and the institutional capacity of each country. The first involves a mix of countercyclical fiscal and monetary policies with appropriate (and, as we will argue, generally intermediate) exchange rate regimes. The second includes a set of capital management techniques aimed at guaranteeing healthy private and public-sector balance sheets. To facilitate economic growth, such interventions through the business cycle should aim at developing sound fiscal systems that provide the necessary resources for the public sector to do its job, a competitive exchange rate and moderate long-term real interest rates. These conditions, together with deep financial markets that provide suitably priced investment finance in domestic currency with sufficiently long maturities, are the best contribution that macroeconomics can make to growth. The paper is divided in five sections, the first of which is this introduction. The second tries to derive some "stylized facts" about financial and real macroeconomic instability in developing countries. The following two analyze the two policy packages mentioned in the previous paragraph. In lieu of conclusions, the last takes a brief look at the implications of this framework for international cooperation

Students’ Satisfaction On Blended Learning During The New Normal: Input To Curriculum Review

Blended learning has been popular during this new normal. It is a mixture of online and face-to-face mode of learning. This study assessed the level of students’ satisfaction in blended learning and its effect to the academic performance of college freshmen. A concoction of quantitative and qualitative approach was used in this study. In quantitative approach, descriptive-correlation design was employed. Sixty students enrolled in Mathematics in the Modern World of Bachelor of Science in Fisheries were respondents of the study. Findings showed 62 percent are male, 93 percent are single, most or 45 percent have available internet connection but sometimes stable, 78 percent use mobile data connection and smartphone found to be the rank 1 available gadget at home; the mean grade of students is 85.88 with standard deviation of 5.5; the over-all satisfaction level of students with the used of blended is 4.31 describes very much satisfied. The grade of students differ when grouped according to sex. Sex and classroom interaction significantly associated in the improvement of students performance in mathematics. It is concluded that teaching and learning process at this new normal is very challenging however all teachers need to take the challenge of teaching in order to achieve the maximum satisfaction and optimum academic performance as well. Blended learning has been difficult to implement but once instruction is done with all-out interaction where every learner are encourage to raise their doubts and clarified by teacher, where instructions are effective, instructors welcome all members to be comfortable during discussions, where there is observance of proper discipline and when the gadgets being used are in good technical condition. If students have sufficient and advanced technology as well as robust internet access, the blended learning system would have been an effective learning and teaching approach

Reforming the Global Reserve System

The magnitude of the ongoing world financial meltdown and its real economic effects has lessened the focus on another set of major international financial issues that had been the center of significant attention in recent years: large global imbalances and their links to the global reserve system. Rising public sector debts and the massive monetary expansion in the United States, coupled with the highly uneven macroeconomic policy stimulus taking place throughout the world are two major reasons why renewed attention has to be paid to these issues

Self-management of context-aware overlay ambient networks

Ambient Networks (ANs) are dynamically changing and heterogeneous as they consist of potentially large numbers of independent, heterogeneous mobile nodes, with spontaneous topologies that can logically interact with each other to share a common control space, known as the Ambient Control Space. ANs are also flexible i.e. they can compose and decompose dynamically and automatically, for supporting the deployment of cross-domain (new) services. Thus, the AN architecture must be sophisticatedly designed to support such high level of dynamicity, heterogeneity and flexibility. We advocate the use of service specific overlay networks in ANs, that are created on-demand according to specific service requirements, to deliver, and to automatically adapt services to the dynamically changing user and network context. This paper presents a self-management approach to create, configure, adapt, contextualise, and finally teardown service specific overlay networks

Alterations in prefrontal-limbic functional activation and connectivity in chronic stress-induced visceral hyperalgesia.

Repeated water avoidance stress (WAS) induces sustained visceral hyperalgesia (VH) in rats measured as enhanced visceromotor response to colorectal distension (CRD). This model incorporates two characteristic features of human irritable bowel syndrome (IBS), VH and a prominent role of stress in the onset and exacerbation of IBS symptoms. Little is known regarding central mechanisms underlying the stress-induced VH. Here, we applied an autoradiographic perfusion method to map regional and network-level neural correlates of VH. Adult male rats were exposed to WAS or sham treatment for 1 hour/day for 10 days. The visceromotor response was measured before and after the treatment. Cerebral blood flow (CBF) mapping was performed by intravenous injection of radiotracer ([(14)C]-iodoantipyrine) while the rat was receiving a 60-mmHg CRD or no distension. Regional CBF-related tissue radioactivity was quantified in autoradiographic images of brain slices and analyzed in 3-dimensionally reconstructed brains with statistical parametric mapping. Compared to sham rats, stressed rats showed VH in association with greater CRD-evoked activation in the insular cortex, amygdala, and hypothalamus, but reduced activation in the prelimbic area (PrL) of prefrontal cortex. We constrained results of seed correlation analysis by known structural connectivity of the PrL to generate structurally linked functional connectivity (SLFC) of the PrL. Dramatic differences in the SLFC of PrL were noted between stressed and sham rats under distension. In particular, sham rats showed negative correlation between the PrL and amygdala, which was absent in stressed rats. The altered pattern of functional brain activation is in general agreement with that observed in IBS patients in human brain imaging studies, providing further support for the face and construct validity of the WAS model for IBS. The absence of prefrontal cortex-amygdala anticorrelation in stressed rats is consistent with the notion that impaired corticolimbic modulation acts as a central mechanism underlying stress-induced VH

Energy Efficiency of Hybrid-Power HetNets: A Population-like Games Approach

In this paper, a distributed control scheme based on population games is proposed. The controller is in charge of dealing with the energy consumption problem in a Heterogeneous Cellular Network (HetNet) powered by hybrid energy sources (grid and renewable energy) while guaranteeing appropriate quality of service (QoS) level at the same time. Unlike the conventional approach in population games, it considers both atomicity and non-anonymity. Simulation results show that the proposed population-games approach reduces grid consumption by up to about 12% compared to the traditional best-signal level association policy.U.S. Air Force Office of Scientific Research FA9550-17-1-0259Ministerio de Cultura y Deporte DPI2016-76493-C3-3-RMinisterio de Economía y Empresa DPI2017-86918-