Louisiana State University

About: Louisiana State University is a education organization based out in Baton Rouge, Louisiana, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 40206 authors who have published 76587 publications receiving 2566076 citations. The organization is also known as: LSU & Louisiana State University and Agricultural and Mechanical College.

Orthogonal designs with maximal rates

Abstract: Orthogonal designs have been used as space-time block codes for wireless communications with multiple transmit antennas, which can achieve full transmit diversity and have a very simple decoupled maximum-likelihood decoding algorithm. The rate of an orthogonal design is defined as the ratio of the number of transmitted information symbols in a block of channel uses to the length of the given block, which reflects the bandwidth efficiency of the employed space-time block code constructed from the orthogonal design. This paper focuses on the analysis and synthesis of orthogonal designs with the maximum possible rates, which may be real or complex and square or rectangular matrices. We first provide several representations of orthogonal designs and their characterizations in terms of Hurwitz-Radon matrix equations. Next, we observe that the real orthogonal designs, square or rectangular, and the complex square orthogonal designs with maximal rates have been well understood from the existing results in the mathematics literature which can be dated back to 1890s. However, unfortunately, it is not the case for the complex rectangular orthogonal designs with rates as high as possible. We then construct a class of complex orthogonal designs for any number of transmit antennas. The proposed complex orthogonal designs for the number of transmit antennas n=2m-1 and 2m have the same rate m+1 and 2m, where m is any natural number. Finally, we demonstrate that, for n=2m-1 and 2m with any given natural number m, the value m+1 and 2m is the maximum possible rate that the complex orthogonal designs, square or rectangular, with n transmit antennas can achieve.

Carbon sequestration potential of second-growth forest regeneration in the Latin American tropics

Abstract: Regrowth of tropical secondary forests following complete or nearly complete removal of forest vegetation actively stores carbon in aboveground biomass, partially counterbalancing carbon emissions from deforestation, forest degradation, burning of fossil fuels, and other anthropogenic sources. We estimate the age and spatial extent of lowland second-growth forests in the Latin American tropics and model their potential aboveground carbon accumulation over four decades. Our model shows that, in 2008, second-growth forests (1 to 60 years old) covered 2.4 million km2 of land (28.1% of the total study area). Over 40 years, these lands can potentially accumulate a total aboveground carbon stock of 8.48 Pg C (petagrams of carbon) in aboveground biomass via low-cost natural regeneration or assisted regeneration, corresponding to a total CO2 sequestration of 31.09 Pg CO2. This total is equivalent to carbon emissions from fossil fuel use and industrial processes in all of Latin America and the Caribbean from 1993 to 2014. Ten countries account for 95% of this carbon storage potential, led by Brazil, Colombia, Mexico, and Venezuela. We model future land-use scenarios to guide national carbon mitigation policies. Permitting natural regeneration on 40% of lowland pastures potentially stores an additional 2.0 Pg C over 40 years. Our study provides information and maps to guide national-level forest-based carbon mitigation plans on the basis of estimated rates of natural regeneration and pasture abandonment. Coupled with avoided deforestation and sustainable forest management, natural regeneration of second-growth forests provides a low-cost mechanism that yields a high carbon sequestration potential with multiple benefits for biodiversity and ecosystem services.

Microfluidic synthesis of nanomaterials.

Abstract: An overview of the current information and analyses on the microfluidic synthesis of different types of nanomaterial, including metallic and silica nanoparticles and quantum dots, is presented. Control of particle size, size distribution, and crystal structure of nanomaterials are examined in terms of the special features of microfluidic reactors.