Jet Formation in the magnetospheres of supermassive black holes: analytic solutions describing energy loss through Blandford-Znajek processes

In this paper, we provide exact solutions for the extraction of energy from a rotating black hole via both the electromagnetic Poynting flux and matter currents. By appropriate choice of a radially independent poloidal function $\Lambda(\theta)$, we find solutions where the dominant outward energy flux is along the polar axis, consistent with a jet-like collimated outflow, but also with a weaker flux of energy along the equatorial plane. Unlike all the previously obtained solutions (Blandford & Znajek (1977), Menon & Dermer (2005)), the magnetosphere is free of magnetic monopoles everywhere

Executive Power: Rethinking the Modalities of Control

The Honorable Sundaresh Menon, Chief Justice of the Supreme Court of Singapore, delivered the 2018-2019 Bernstein Lecture in Comparative Law titled Executive Power: Rethinking the Modalities of Control. The Chief Justice discussed the control of executive power in Singapore as compared to other legal systems. Co-sponsored by the Center for International and Comparative Law and the Office of the Dean

From Spaghetti Bowl to Jigsaw Puzzle? Addressing the Disarray in the World Trade System

The rise of mega-regionals such as the Regional Comprehensive Economic Partnership (RCEP) and the Trans-Pacific Partnership (TPP) suggests that the world trade system is fragmenting to the point it appears more like a jigsaw puzzle than a spaghetti bowl. There are both regional and global jigsaw puzzles to be solved—in that order—to clean up the world trade system. But is this even likely? The difficulties of free trade agreement (FTA) consolidation at the regional level are well known, while piecing together the blocs around the world to form a coherent whole is even more challenging. In this context, a way forward is to return to the most widely used modality of trade liberalization—unilateral actions—but this time involving the multilateralization of preferences rather than unreciprocated reductions in tariff rates. As more and more FTAs are negotiated, preference erosion sets in, reducing the resistance of FTA partners to multilateralization. Multilateralization of preferences may then present a practical way forward in addressing the disarray in the world trade system

Famine in Malawi: Causes and Consequences

human development, climate change

Cambodia's Persistent Dollarization: Causes and Policy Options

Cambodia's economic and social achievements over the past ten years have been the most impressive in its history. Nevertheless, Cambodia today is still as dollarized, if not more so, than it was ten years ago. What is this so, and what, if anything, should the Government do? This paper attempts to answer both these questions, by examining the reasons behind the apparent paradox between a decade of economic and political improvements and continued dollarization, and drawing policy implications from it. We advise against pursuing enforced dedollarization, and advocate a policy option that focuses instead on accelerating accommodative reforms, especially in the financial sector and on legal and institutional reforms. We also identify a host of institutional barriers that need to be overcome to prepare the groundwork for a natural process of de-dollarization.Cambodia; dollarization; exchange rates; currency board; hysteresis

Got Technology? The Impact of Computers and Cell-phones on Productivity in a Difficult Business Climate: Evidence from Firms with Female Owners in Kenya

Firms in Kenya rely on technologies such as computers, cell-phones, and generators to overcome constraints associated with regulations, infrastructure, security, workforce, corruption, and finance. This study shows that such reliance has significant positive impacts on productivity as measured by value-added per worker, especially for firms with female principal owners. The exogenous component of technology ownership is isolated by using information on the regional presence of missionary schools from Kenya’s colonial past, as well as geographical indicators such as rainfall, changes in forest cover, and average regional elevation. Results indicate that for firms with female owners, technology adoption improves value-added per worker by about 49 percentage points. It is also statistically evident that for such firms, the ownership of technologies such as computers, cell-phones, and generators succeeds in mitigating the costs of business obstacles. For male-owned firms, such patterns are absent.Technology, Computers, Cell-phones, Business Obstacles, Kenya, Firms, Female Owners

Managing Success in Viet Nam: Macroeconomic Consequences of Large Capital Inflows with Limited Policy Tools

Viet Nam has experienced spectacular economic growth over the past decade, in part the result of massive foreign direct investment (FDI) inflows. Although much has been written on the impacts of FDI in developing countries, previous studies have generally ignored macroeconomic consequences in cost-benefit assessments. These macroeconomic aspects can be particularly important in transitional economies like Viet Nam, where some of the tools for macroeconomic stabilization may be blunt or unavailable. First, capital inflow growth needs to be accommodated by real exchange rate appreciation. In dollarized economies like Viet Nam, the nominal exchange rate cannot be relied upon to deliver it, so inflation usually results. In these economies, it is also difficult for the central bank to conduct open market operations to sterilize large capital inflows or mop up excess liquidity. Again, this could feed inflation. The combination of a young and inexperienced banking system and an investment-hungry state-owned enterprises (SOE) sector only exacerbates the situation, and increases the risk of imbalances that could result in crisis.capital inflow; macroeconomic adjustment; FDI; real exchange rate; Viet Nam

Verification of feature regions for stops and fricatives in natural speech

The presence of acoustic cues and their importance in speech perception have long remained debatable topics. In spite of several studies that exist in this eld, very little is known about what exactly humans perceive in speech. This research takes a novel approach towards understanding speech perception. A new method, named three-dimensional deep search (3DDS), was developed to explore the perceptual cues of 16 consonant-vowel (CV) syllables, namely /pa/, /ta/, /ka/, /ba/, /da/, /ga/, /fa/, /Ta/, /sa/, /Sa/, /va/, /Da/, /za/, /Za/, from naturally produced speech. A veri cation experiment was then conducted to further verify the ndings of the 3DDS method. For this pur- pose, the time-frequency coordinate that de nes each CV was ltered out using the short-time Fourier transform (STFT), and perceptual tests were then conducted. A comparison between unmodi ed speech sounds and those without the acoustic cues was made. In most of the cases, the scores dropped from 100% to chance levels even at 12 dB SNR. This clearly emphasizes the importance of features in identifying each CV. The results con rm earlier ndings that stops are characterized by a short-duration burst preceding the vowel by 10 cs in the unvoiced case, and appearing almost coincident with the vowel in the voiced case. As has been previously hypothesized, we con rmed that the F2 transition plays no signi cant role in consonant identi cation. 3DDS analysis labels the /sa/ and /za/ perceptual features as an intense frication noise around 4 kHz, preceding the vowel by 15{20 cs, with the /za/ feature being around 5 cs shorter in duration than that of /sa/; the /Sa/ and /Za/ events are found to be frication energy near 2 kHz, preceding the vowel by 17{20 cs. /fa/ has a relatively weak burst and frication energy over a wide-band including 2{6 kHz, while /va/ has a cue in the 1.5 kHz mid-frequency region preceding the vowel by 7{10 cs. New information is established regarding /Da/ and /Ta/, especially with regards to the nature of their signi cant confusions