Energy in Yang-Mills on a Riemann Surface

Sengupta's lower bound for the Yang-Mills action on smooth connections on a bundle over a Riemann surface generalizes to the space of connections whose action is finite. In this larger space the inequality can always be saturated. The Yang-Mills critical sets correspond to critical sets of the energy action on a space of paths. This may shed light on Atiyah and Bott's conjecture concerning Morse theory for the space of connections modulo gauge transformations.Comment: 7 pages, 2 figures, Latex2e with epsfig, submitted to Journal of Mathematical Physic

The possibility of a metal insulator transition in antidot arrays induced by an external driving

It is shown that a family of models associated with the kicked Harper model is relevant for cyclotron resonance experiments in an antidot array. For this purpose a simplified model for electronic motion in a related model system in presence of a magnetic field and an AC electric field is developed. In the limit of strong magnetic field it reduces to a model similar to the kicked Harper model. This model is studied numerically and is found to be extremely sensitive to the strength of the electric field. In particular, as the strength of the electric field is varied a metal -- insulator transition may be found. The experimental conditions required for this transition are discussed.Comment: 6 files: kharp.tex, fig1.ps fig2.ps fi3.ps fig4.ps fig5.p

The Effect of High Dose Total Body Irradiation on ACTH, Corticosterone, and Catecholamines in the Rat

Total body irradiation (TBI) or partial body irradiation is a distinct risk of accidental, wartime, or terrorist events. Total body irradiation is also used as conditioning therapy before hematopoietic stem cell transplantation. This therapy can result in injury to multiple tissues and might result in death as a result of multiorgan failure. The hypothalamic–pituitary–adrenal (HPA) axis could play a causative role in those injuries, in addition to being activated under conditions of stress. In a rat model of TBI, we have established that radiation nephropathy is a significant lethal complication, which is caused by hypertension and uremia. The current study assessed HPA axis function in rats undergoing TBI. Using a head-shielded model of TBI, we found an enhanced response to corticotropin-releasing hormone (CRH) in vitro in pituitaries from irradiated compared with nonirradiated rats at both 8 and 70 days after 10-Gy single fraction TBI. At 70, but not 8 days, plasma adrenocorticotrophic hormone (ACTH) and corticosterone levels were increased significantly in irradiated compared with nonirradiated rats. Plasma aldosterone was not affected by TBI at either time point, whereas plasma renin activity was decreased in irradiated rats at 8 days. Basal and stimulated adrenal steroid synthesis in vitro was not affected by TBI. In addition, plasma epinephrine was decreased at 70 days after TBI. The hypothalamic expression of CRH messenger RNA (mRNA) and hippocampal expression of glucocorticoid receptor mRNA were unchanged by irradiation. We conclude that the hypertension of radiation nephropathy is not aldosterone or catecholamine-dependent but that there is an abscopal activation of the HPA axis after 10 Gy TBI. This activation was attributable at least partially to enhanced pituitary ACTH production

Band Distributions for Quantum Chaos on the Torus

Band distributions (BDs) are introduced describing quantization in a toral phase space. A BD is the uniform average of an eigenstate phase-space probability distribution over a band of toral boundary conditions. A general explicit expression for the Wigner BD is obtained. It is shown that the Wigner functions for {\em all} of the band eigenstates can be reproduced from the Wigner BD. Also, BDs are shown to be closer to classical distributions than eigenstate distributions. Generalized BDs, associated with sets of adjacent bands, are used to extend in a natural way the Chern-index characterization of the classical-quantum correspondence on the torus to arbitrary rational values of the scaled Planck constant.Comment: 12 REVTEX page

Oligopoly Price Discrimination: The Role of Inventory Controls

Inventory controls, used most notably by airlines, are sales limits assigned to individual prices. While typically viewed as a tool to manage demand uncertainty, we argue that inventory controls can also facilitate intertemporal price discrimination in oligopoly. In our model, competing firms first choose quantity and then choose prices in a series of advance-purchase markets. When demand becomes less elastic over time, as is the case in airline markets, a monopolist can easily price discriminate; however, we show that oligopoly firms generally cannot. We also show that using inventory controls allows oligopoly firms to set increasing prices, regardless of whether or not demand is uncertain

Intertemporal Price Discrimination in Sequential Quantity-Price Games

This paper develops an oligopoly model in which firms first choose capacity and then compete in prices in a series of advance-purchase markets. We show the existence of multiple sales opportunities creates strong competitive forces that prevent firms from utilizing intertemporal price discrimination. We then show that intertemporal price discrimination is possible, but only when firms adopt inventory controls (sales limit restrictions) and demand becomes more inelastic over time. Therefore, in addition to being useful to manage demand uncertainty, inventory controls are also a tool to soften price competition. We also discuss model extensions, including product differentiation, aggregate demand uncertainty, and longer sales horizons

Rancangan Tata Kelola Ti Untuk Institusi Pemerintah Studi Kasus Bappenas

Penerapan tata kelola pemerintahan dan percepatan penerapan teknologi informasi pada pemerintahan membuat institusi-institusi pemerintah harus meningkatkan fungsi teknologi informasinya. Dengan meningkatnya peran teknologi informasi maka investasi di bidang teknologi informasi semakin besar dan semakin kompleks dalam pengelolaannya. Oleh karena itu dibutuhkan suatu tata kelola teknologi informasi yang sesuai dengan kebutuhan masing-masing organisasinya. Bappenas sebagai institusi perencanaan pemerintah merasa perlu untuk memiliki suatu tata kelola teknologi informasi yang baik agar investasi teknologi informasinya dapat berjalan dengan baik. Tulisan ini membahas rancangan suatu tata kelola teknologi informasi untuk Bappenas dengan menggunakan gabungan model tata kelola teknologi informasi diantaranya model Peterson, model Weill & Ross, model ITGI focus area, model AS 8015 standar Australia, dan kontrol objektif dari COBIT. Dari keseluruhan model tersebut dapat dilihat seberapa jauh tingkat kematangan tata kelola TI pada Bappenas yang kemudian akan ditentukan solusi untuk mencapainya

Penerapan Metode Analytic Hierarchy Process Dalam Sistem Penunjang Keputusan Untuk Pemilihan Asuransi

Memilih produk asuransi membutuhkan proses pengambilan keputusan yang cukup rumit karena melibatkan banyak kriteria seperti brand image Perusahaan, besar premi yang harus dibayarkan, kemudahan prosedur klaim, dan lain sebagainya, sebagai bahan pertimbangan dalam prosesnya. Salah satu metode yang sesuai untuk digunakan dalam pengambilan keputusan ini adalah Analytic Hierarchy Process (AHP). Penelitian ini dilakukan untuk mengetahui apakah metode AHP dapat digunakan dalam suatu sistem penunjang keputusan. Untuk mendukung penelitian, dibuat suatu sistem penunjang keputusan yang berisi modul simulasi untuk memilih produk asuransi. Berdasarkan skenario pengujian yang dibuat, diperoleh hasil bahwa solusi yang diberikan oleh sistem cukup akurat dan mendekati kemampuan manusia dalam mengambil keputusan