CORRECTING FOR BIASES WHEN ESTIMATING PRODUCTION FUNCTIONS: AN ILLUSION OF THE LAWS OF ALGEBRA?

this paper argues that the true cause of the endogeneity bias that allegedly appears when estimating production functions, and which the literature has tried to deal with since the 1940s, is s imply the result of omitted-variable bias due to an incorrect approximation to an accounting identity. As a result we question recent attempts to solve the problem by developing new estimators.

Nucleate pool boiling in the long duration low gravity environment of the Space Shuttle

The results are presented of an experimental study of nucleate pool boiling performed in the low gravity environment of the space shuttle. Photographic observations of pool boiling in Freon 113 were obtained during the 'Tank Pressure Control Experiment,' flown on the Space Transportation System, STS-43 in August 1991. Nucleate boiling data from large (relative to bubble size) flat heating surfaces (0.1046 by 0.0742 m) was obtained at very low heat fluxes (0.22 to 1.19 kW/sq m). The system pressure and the bulk liquid subcooling varied in the range of 40 to 60 kPa and 3 to 5 C respectively. Thirty-eight boiling tests, each of 10-min duration for a given heat flux, were conducted. Measurements included the heater power, heater surface temperature, the liquid temperature and the system pressure as functions of heating time. Video data of the first 2 min of heating was recorded for each test. In some tests the video clearly shows the inception of boiling and the growth and departure of bubbles from the surface during the first 2 min of heating. In the absence of video data, the heater temperature variation during heating shows the inception of boiling and stable nucleate boiling. During the stable nucleate boiling, the wall superheat varied between 2.8 to 3.8 C for heat fluxes in the range of 0.95 to 1.19 kW/sq m. The wall superheat at the inception of boiling varied between 2 to 13 C

Chemically gated electronic structure of a superconducting doped topological insulator system

Angle resolved photoemission spectroscopy is used to observe changes in the electronic structure of bulk-doped topological insulator Cu$_x$Bi$_2$Se$_3$ as additional copper atoms are deposited onto the cleaved crystal surface. Carrier density and surface-normal electrical field strength near the crystal surface are estimated to consider the effect of chemical surface gating on atypical superconducting properties associated with topological insulator order, such as the dynamics of theoretically predicted Majorana Fermion vortices

Ballisticity of nanotube FETs: Role of phonon energy and gate bias

We investigate the role of electron-phonon scattering and gate bias in degrading the drive current of nanotube MOSFETs. Our central results are: (i) Optical phonon scattering significantly decreases the drive current only when gate voltage is higher than a well-defined threshold. It means that elastic scattering mechanisms are most detrimental to nanotube MOSFETs. (ii) For comparable mean free paths, a lower phonon energy leads to a larger degradation of drive current. Thus for semiconducting nanowire FETs, the drive current will be more sensitive than carbon nanotube FETs because of the smaller phonon energies in semiconductors. (iii) Radial breathing mode phonons cause an appreciable reduction in drive current.Comment: 16 pages, 1 table, 4 figure

Strategi United Sabah Islamic Association (Usia) Dalam Mengembangkan Dakwah Di Kota Kinabalu Malaysia

Dalam realitas kehidupannya, masyarakat Islam selalu dihadapkan denganberbagai persoalan baik internal maupun eksternal. Untuk itu diperlukan aktivitas dakwah sebagai media penguatan pemahaman umat. Tujuan aktivitas dakwah adalah menyampaikan risalah Islam agar panji-panji kebenaran terus mewarnai kehidupan masyarakat di Kota Kinabalu Malaysia. Untuk tegaknya dakwah maka diperlukan strategi tertentu sehingga memudahkan pelaksanaan dakwah itu sendiri. Sebagai salah satu organisasi dakwah terkemuka di Sabah, USIA telah mempraktikkan beberapa strategi untuk mengembangkan dakwah yang terangkum dalam grand strategy dengan cara membentuk jaringan dakwah. Strategi ini erat hubungannya dengan teori jaringan yang dikembangkan oleh Wellman. Kajian ini lebih bersifat induktif kualitatif dengan mengutamakan data hasil wawancara, studi dokumentasi, dan observasi terbatas yang dilakukan selama proses pengumpulan data berlangsung

Probing the internal magnetic field of slowly pulsating B-stars through g modes

We suggest that high-order g modes can be used as a probe of the internal magnetic field of SPB (slowly pulsating B) stars. The idea is based on earlier work by the authors which analytically investigated the effect of a vertical magnetic field on p and g modes in a plane-parallel isothermal stratified atmosphere. It was found that even a weak field can significantly shift the g-mode frequencies -- the effect increases with mode order. In the present study we adopt the classical perturbative approach to estimate the internal field of a 4 solar mass SPB star by looking at its effect on a low-degree ($l=1$) and high-order ($n=20$) g mode with a period of about 1.5 d. We find that a polar field strength of about 110 kG on the edge of the convective core is required to produce a frequency shift of 1%. Frequency splittings of that order have been observed in several SPB variables, in some cases clearly too small to be ascribed to rotation. We suggest that they may be due to a poloidal field with a strength of order 100 kG, buried in the deep interior of the star.Comment: 4 pages, 2 figures (to appear in Astronomy & Astrophysics