Railroads and Local Economic Development: The United States in the 1850s

We use county and individual-level data from 1850 and 1860 to examine the economic impact of gaining access to a railroad. Previous studies have found that rail access was positively correlated with the value of agricultural land at a point in time, and have interpreted this correlation as evidence that rail access chiefly benefitted agricultural land owners in the manner predicted by the Hekscher-Ohlin or Von Theunen models. We use a difference-in-difference strategy, comparing changes in outcomes in counties that gained rail access in the 1850s to those that either gained access earlier or did not have access before the Civil War. Most of the estimated effects are small and the signs are not wholly consistent with either model, under the null hypothesis that agriculture was the chief beneficiary of rail access. For example, we find that rail access appears to have increased urbanization, raised the likelihood of participation in the service sector, decreased agricultural yields, and reduced the share of improved acreage in total land area, opposite to the patterns predicted by either the Heckscher-Ohlin or Von Theunen models.

Molecular theory of elastic constants of liquid crystals. III. Application to smectic phases with tilted orientational order

Using the density functional formalism we derive expression for the distortion free energy for systems with continuous broken symmetry and use it to derive expression for the elastic constants of smectic phases in which director is tilted with respect to the smectic layer normal. As in the previous papers of the series (Phys. Rev. A {\bf 45}, 974 (1992), E {\bf 49}, 501, (1994)) the expressions for the elastic constants are written in terms of order and structural parameters. The structural parameters involve the generalised spherical harmonic coefficients of the direct pair correlation function of an effective isotropic liquid. The density of this effective isotropic liquid depends on the nature and amount of ordering present in the system and is evaluated self- consistently. We estimate the value of elastic constants using reasonable guess for the order and structural- parameters.Comment: 31 pages; 1 Fig. in GIF format, To be appear in Phys. Rev.

Koordinasi Proteksi Adaptif Rele Arus Lebih Digital Menggunakan Metoda Artificial Neural Network Pada Sistem Mesh Dengan Pembangkit Tersebar

Pada sistem mesh yang terkoneksi dengan pembangkit tersebar (Distributed Generation), terdapat kondisi dimana topologi jaringan yang berubah-ubah. Hal tersebut disebabkan oleh waktu operasi dari pembangkit tersebar yang bersifat temporary dan random. Kondisi ini dapat dibedakan yaitu terhubung dengan grid, terhubung grid dan DG1, terhubung grid dan DG2, dan terhubung grid dengan DG1 dan DG2. Akibat topologi jaringan yang berubah-ubah, menyebabkan peningkatan dan penurunan level arus hubung singkat sehingga seting dan koordinasi proteksi awal menjadi tidak efektif dan efisien lagi terhadap konfigurasi jaringan yang ada. Oleh karena itu dibutuhkan sistem proteksi yang setingnya dapat menyesuaikan dengan topologi jaringan yang berubah-ubah. Pada tugas akhir ini akan dirancang koordinasi sistem proteksi rele arah arus lebih yang dapat mengikuti setiap Perubahan kondisi pada topologi jaringan tersebut menggunakan metoda Artificial Neural Network dengan desain plant berbentuk mesh yang terhubung dengan Grid dan DG. Hasil perancangan menunjukan bahwa penggunaan metoda Artificial Neural Network dapat menghasilkan setingan rele yang adaptif mengikuti Perubahan topologi sistem. Dan metoda artificial neural network juga dapat memprediksi setingan rele pada saat terjadi gangguan yang diluar kondisi yang telah dipelajari dalam data learning

Railroads and the Rise of the Factory: Evidence for the United States, 1850-70

Over the course of the nineteenth century manufacturing in the United States shifted from artisan shop to factory production. At the same time United States experienced a "transportation revolution", a key component of which was the building of extensive railroad network. Using a newly created data set of manufacturing establishments linked to county level data on rail access from 1850-70, we ask whether the coming of the railroad increased establishment size in manufacturing. Difference-in-difference and instrument variable estimates suggest that the railroad had a positive effect on factory status. In other words, Adam Smith was right -- the division of labor in nineteenth century American manufacturing was limited by the extent of the market.

Analisa Pengaruh Koordinasi Peralatan Proteksi Terhadap Karakteristik Voltage Sag Di PT. Pupuk Kaltim (PKT) Bontang

Program paket merupakan software simulasi transien pada sistem tenaga yang digunakan untuk menganalisa pengujian jaringan listrik di industri pada kondisi saat gangguan. Untuk meneliti karakteristik voltage sag pada sistem jaringan listrik di industri dalam kondisi saat gangguan, digunakan dua metode untuk koordinasi peralatan proteksi. Keluaran dari hasil simulasi berupa kurva transien tegangan terhadap durasi waktu gangguan yang merupakan karakteristik voltage sag. Kurva hasil simulasi ini dievaluasi dengan kurva standar CBEMA, ITIC, dan SEMI yang telah distandarkan untuk performa jaringan. Hasil simulasi hubung singkat 3 fasa di titik Fault 2 menyebabkan tegangan sisa sebesar 88,4 % di tiap fasa, hubung singkat 1 fasa ke tanah sebesar 81,4 % di fasa A, 98,6 % di fasa B, dan 96,2 % di fasa C, hubung singkat antar fasa sebesar 92,6 % di fasa A, 105,9 % di fasa B, 87,6 % di fasa C. Metode kedua yaitu dengan CB atau pemutus dari hasil evaluasi simulasi didapatkan durasi gangguan yang lebih kecil dari metode pertama yaitu tanpa peralatan proteksi

Dissipative dynamics of vortex arrays in trapped Bose-condensed gases: neutron stars physics on μ\muK scale

We develop a theory of dissipative dynamics of large vortex arrays in trapped Bose-condensed gases. We show that in a static trap the interaction of the vortex array with thermal excitations leads to a non-exponential decay of the vortex structure, and the characteristic lifetime depends on the initial density of vortices. Drawing an analogy with physics of pulsar glitches, we propose an experiment which employs the heating of the thermal cloud in the course of the decay of the vortex array as a tool for a non-destructive study of the vortex dynamics.Comment: 4 pages, revtex; revised versio

Young people today: news media, policy and youth justice

The new sociology of childhood sees children as competent social agents with important contributions to make. And yet the phase of childhood is fraught with tensions and contradictions. Public policies are required, not only to protect children, but also to control them and regulate their behaviour. For children and young people in the UK, youth justice has become increasingly punitive. At the same time, social policies have focused more on children's inclusion and participation. In this interplay of conflict and contradictions, the role the media play is critical in contributing to the moral panic about childhood and youth. In this article, we consider media representations of “antisocial” children and young people and how this belies a moral response to the nature of contemporary childhood. We conclude by considering how a rights-based approach might help redress the moralised politics of childhood representations in the media

Planned Vaginal Birth or Elective Repeat Caesarean: Patient Preference Restricted Cohort with Nested Randomised Trial

A study conducted in Australia provides new data on the outcomes for mother and baby associated with either planned vaginal birth, or elective repeat caesarean section following a previous caesarean section