902 research outputs found
Validating Continuum Lowering Models via Multi-Wavelength Measurements of Integrated X-ray Emission
X-ray emission spectroscopy is a well-established technique used to study
continuum lowering in dense plasmas. It relies on accurate atomic physics
models to robustly reproduce high-resolution emission spectra, and depends on
our ability to identify spectroscopic signatures such as emission lines or
ionization edges of individual charge states within the plasma. Here we
describe a method that forgoes these requirements, enabling the validation of
different continuum lowering models based solely on the total intensity of
plasma emission in systems driven by narrow-bandwidth x-ray pulses across a
range of wavelengths. The method is tested on published Al spectroscopy data
and applied to the new case of solid-density partially-ionized Fe plasmas,
where extracting ionization edges directly is precluded by the significant
overlap of emission from a wide range of charge states
Peran Pemerinta terhadap Pengelolaan Pasar Perspektifn EkonomiI Salam (Studi Kasus Pasar Bersehati Kota Manado)
Penelitian ini berkenaan dengan studi salah satu aspek terpenting dalam perekonomian, yaitu pasar. Adapun pokok masalah yang di angkat. Adalah bagaimana peran pemerinta terhada p pengelolaan pasar dalam perspektif ekonomi isalam, dengan mengambil salasatu kasus yang ada di salah satu pasar Tradisional di Kota Manado, yaitu pasar bersehati. Penelitian ini sengaja diangkat untuk mengetahui seberapa besar peran pemerinta terhadap pengelolaan pasar bersehati dan untuk mengetahui apakah peran tersebut suda sesuai dengan konsep ekonomi islam atau tidak. Menajemen pengeloaan pasar yang ideal dan peran pemerinta menjadi bahasan utama dalam upaya menjalankan jenis penelitian kualitatif deskriptif ini. Sedangkan untuk menjawab kesesuaian dengan konsep islam maka penelti menggunakan pendekatan sosiologis normatif. Setelah melalui proses penelitian peneliti menemukan fakta bahwa peran pemerinta saat ini masi lebih kepada peran fisik, yaitu social infrastruktur dan kebersihan, meski pengawasan terhadap adanya penimbunan harga tetap di lakukan. Di sisi lain, pedagang telah cukup merasakan dengan adanya peran tersebut dengan adanya rasa nyaman dan betah. Dalam hubungannya dengan konsep Islam, peran tesebut di nilai belum signifikan dan agak berbeda. Sebab, dalam Islam terdapat beberapa laranagan pokok yang sulit untuk di laksanakan, sepertiadanyadaganganbarang haram yang tentusajamasihada di masyarakat, seperti daging babi dan sebagainy
LAND MARKETS AND LEGAL CONTRADICTIONS IN THE PERI-URBAN AREA OF ACCRA GHANA: INFORMANT INTERVIEWS AND SECONDARY DATA INVESTIGATIONS
The peri-urban area of Accra is experiencing a rapid transformation. A robust urban and agricultural land market has emerged, characterized by purchases, rapidly rising real land prices, and outsiders from Accra acquiring agricultural holdings for residential and commercial use. The fact that residences are being built, commercial firms are being established, and large firms are acquiring land for commercial interests attests to the ability of the customary system to enable transfers for productive activity. Nevertheless, limited or uncertain property rights increase investment costs and differential access to information in the land market affects equity. This paper seeks to better understand: (a) the land market in peri-urban Accra, (b) the process by which land held by indigenous communities is transferred to outsiders enabling the conversion of unoccupied or agricultural land into residential or commercial uses, and (c) the contradictions and frictions that exist at the interface of land transfers under customary and statutory systems. It further seeks to examine the possibility that uncertain property rights and high litigation costs are constraining commercial and agricultural investment, and to identify the economic and social factors that determine levels of premiums associated with transactions, and the duration of the customary allocation.Land tenure -- Ghana -- Accra Region, Land tenure -- Law and legislation - -Ghana, Land use, urban -- Ghana -- Accra Region, Real property -- Ghana -- Accra Region, Land reform -- Law and legislation -- Ghana, Land markets -- Ghana, Land tenure, urban -- Ghana, Land administration -- Law and legislation -- Ghana, Tenure types, Traditional -- Ghana, Research methods, Land Economics/Use,
Identification of transcriptional and metabolic programs related to mammalian cell size
SummaryBackgroundRegulation of cell size requires coordination of growth and proliferation. Conditional loss of cyclin-dependent kinase 1 in mice permits hepatocyte growth without cell division, allowing us to study cell size in vivo using transcriptomics and metabolomics.ResultsLarger cells displayed increased expression of cytoskeletal genes but unexpectedly repressed expression of many genes involved in mitochondrial functions. This effect appears to be cell autonomous because cultured Drosophila cells induced to increase cell size displayed a similar gene-expression pattern. Larger hepatocytes also displayed a reduction in the expression of lipogenic transcription factors, especially sterol-regulatory element binding proteins. Inhibition of mitochondrial functions and lipid biosynthesis, which is dependent on mitochondrial metabolism, increased the cell size with reciprocal effects on cell proliferation in several cell lines.ConclusionsWe uncover that large cell-size increase is accompanied by downregulation of mitochondrial gene expression, similar to that observed in diabetic individuals. Mitochondrial metabolism and lipid synthesis are used to couple cell size and cell proliferation. This regulatory mechanism may provide a possible mechanism for sensing metazoan cell size
Fast cortical keypoints for real-time object recognition
Best-performing object recognition algorithms employ a large number features extracted on a dense grid, so they are too slow for real-time and active vision. In this paper we present
a fast cortical keypoint detector for extracting meaningful points from images. It is competitive with state-of-the-art
detectors and particularly well-suited for tasks such as object recognition. We show that by using these points we can
achieve state-of-the-art categorization results in a fraction of the time required by competing algorithms
Phase-differencing in stereo vision: solving the localisation problem
Complex Gabor filters with phases in quadrature are often used to model even- and odd-symmetric simple cells in the primary visual cortex. In stereo vision, the phase difference between the responses of the left and right views can be used to construct a disparity or depth map. Various constraints can be applied in order to construct smooth maps, but this leads to very imprecise depth transitions. In this theoretical paper we show, by using lines and edges as image primitives, the origin of the localisation problem. We also argue that disparity should be attributed to lines and edges, rather than trying to construct a 3D surface map in cortical area V1. We derive allowable translation ranges which yield correct disparity estimates, both for left-view centered vision and for cyclopean vision
Fast and accurate multi-scale keypoints based on end-stopped cells
Increasingly more applications in computer vision employ interest points. Algorithms like SIFT and
SURF are all based on partial derivatives of images smoothed with Gaussian filter kemels. These
algorithrns are fast and therefore very popular
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