Texas A&M University

About: Texas A&M University is a education organization based out in College Station, Texas, United States. It is known for research contribution in the topics: Population & Gene. The organization has 72169 authors who have published 164372 publications receiving 5764236 citations.

Medium access control protocols using directional antennas in ad hoc networks

Abstract: Using directional antennas can be beneficial for wireless ad hoc networks consisting of a collection of wireless hosts. To best utilize directional antennas, a suitable medium access control (MAC) protocol must be designed. Current MAC protocols, such as the IEEE 802.11 standard, do not benefit when using directional antennas, because these protocols have been designed for omnidirectional antennas. In this paper, we attempt to design new MAC protocols suitable for ad hoc networks based on directional antennas.

The fate of nitrogen and phosphorus at the land-sea margin of the North Atlantic Ocean

Abstract: Five large rivers that discharge on the western North Atlantic continental shelf carry about 45% of the nitrogen (N) and 70% of the phosphorus (P) that others estimate to be the total flux of these elements from the entire North Atlantic watershed, including North, Central and South America, Europe, and Northwest Africa. We estimate that 61 · 109 moles y-1 of N and 20 · 109 moles y-1 of P from the large rivers are buried with sediments in their deltas, and that an equal amount of N and P from the large rivers is lost to the shelf through burial of river sediments that are deposited directly on the continental slope. The effective transport of active N and P from land to the shelf through the very large rivers is thus reduced to 292 · 109 moles y-1 of N and 13 · 109 moles y-1 of P.

Combined results of searches for the standard model Higgs boson in pp collisions at √s = 7 TeV

Abstract: Combined results are reported from searches for the standard model Higgs boson in proton-proton collisions at sqrt(s)=7 TeV in five Higgs boson decay modes: gamma pair, b-quark pair, tau lepton pair, W pair, and Z pair. The explored Higgs boson mass range is 110-600 GeV. The analysed data correspond to an integrated luminosity of 4.6-4.8 inverse femtobarns. The expected excluded mass range in the absence of the standard model Higgs boson is 118-543 GeV at 95% CL. The observed results exclude the standard model Higgs boson in the mass range 127-600 GeV at 95% CL, and in the mass range 129-525 GeV at 99% CL. An excess of events above the expected standard model background is observed at the low end of the explored mass range making the observed limits weaker than expected in the absence of a signal. The largest excess, with a local significance of 3.1 sigma, is observed for a Higgs boson mass hypothesis of 124 GeV. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-600 (110-145) GeV is estimated to be 1.5 sigma (2.1 sigma). More data are required to ascertain the origin of this excess.

The Cost to Firms of Cooking the Books

Abstract: We examine the penalties imposed on the 585 firms targeted by SEC enforcement actions for financial misrepresentation from 1978–2002, which we track through November 15, 2005. The penalties imposed on firms through the legal system average only $3.83. In the cross section, the reputation loss is positively related to measures of the firm's reliance on implicit contracts. This evidence belies a widespread belief that financial misrepresentation is disciplined lightly. To the contrary, reputation losses impose substantial penalties for cooking the books.

Construction of ultrastable porphyrin Zr metal-organic frameworks through linker elimination

Abstract: A series of highly stable MOFs with 3-D nanochannels, namely PCN-224 (no metal, Ni, Co, Fe), have been assembled with six-connected Zr6 cluster and metalloporphyrins by a linker-elimination strategy. The PCN-224 series not only exhibits the highest BET surface area (2600m2/g) among all the reported porphyrinic MOFs but also remains intact in pH = 0 to pH = 11 aqueous solution. Remarkably, PCN-224(Co) exhibits high catalytic activity for the CO2/propylene oxide coupling reaction and can be used as a recoverable heterogeneous catalyst.