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Now showing items 1 - 16 of 122

  • Clear as Mud: Planning for the Rebuilding of New Orleans, by Robert B. Olshansky and Laurie A. Johnson.

    Brooks, J. S.   Becker, R. W.  

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  • The Quest for Immortality. Science at the Frontiers of Agingby S. Jay Olshansky; Bruce A. Carnes

    Review by: Jean-Marc Rohrbasser  

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  • The Quest for Immortality: Science at the Frontiers of Agingby S. Jay Olshansky; Bruce A. Carnes

    Review by: Brian Charlesworth  

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  • Systems and methods for injecting content

    Aspects of the present disclosure include systems and methods for injecting content into a webpage at or local to a network access gateway. For example, in an embodiment, a network access gateway is provided for accessing the internet. A user logs onto the internet through the network access gateway and request a webpage. The gateway requests the webpage from the webpage provider. Before the gateway delivers the webpage to the user, the gateway, or a content injection engine local to the gateway, injects content, such as, for example, advertisements or other useful information, into the webpage and then sends the altered webpage to the user.
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  • Method and apparatus for acknowledging top data packets

    A data communication network includes a network access unit for coupling one or more computer devices to the network. The network typically has asymmetric upstream and downstream data transmission rates. The network access device implements a method for acknowledging data packets. When a new packet is received by the network access unit from one of the computer devices, the new packet is placed in an outbound queue in the network access unit. When the new packet contains an acknowledgment, previous acknowledgment packets in the outbound queue that have the same source and destination addresses as the new packet are identified and discarded. Remaining packets are transmitted from the outbound queue in the network access unit. By discarding acknowledgment packets in the network access unit, throughput is increased.
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  • Method of forming a conducting structure

    The method of forming a conducting structure consists in applying to a substrate a 2 to 20 nm thick layer of a material transformable into conducting one under the effect of radiation, and irradiating the layer of the material with a modulated beam of charged particles, with the result that the material of the layer on each irradiated area thereof is transformed into a conducting component forming on the substrate a plurality of conducting structure elements, and a nonconducting component which is displaced into the substrate material.
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  • Method and apparatus for noninvasively monitoring parameters of a region of interest in a human body

    Apparatus and methods are provided for monitoring a parameter of a region of interest (ROI) within a first tissue type within a body. A control unit drives a measurement unit to provide an operating condition such that acoustic waves overlap with a region within the ROI that is illuminated by illuminating light such as to generate a first set of tagged photons, and such that the acoustic waves overlap with a region of tissue within a second tissue type that is illuminated by illuminating light such as to generate a second set of tagged photons, the first and second sets of tagged photons being distinguishable from one another. The control unit determines the parameter of the ROI by extracting data portions associated with, respectively, the light response of the ROI and the light response of the second tissue type, by distinguishing between the sets of tagged photons.
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  • Ethernet to ADSL adapter

    An Ethernet ADSL adapter controls data communication between an Ethernet port and an ADSL modem connected to an ADSL channel. The adapter includes a first buffer for storing data packets received at the Ethernet port, a second buffer for storing data packets received from the ADSL modem and a controller. When the first buffer contains a first predetermined number of data packets and data packets are not available for transmission to the Ethernet port, a jamming signal is transmitted from the Ethernet port. The jamming signal inhibits transmission of additional data packets to the Ethernet port by other Ethernet nodes until space is available in the first buffer. When the second buffer contains a second predetermined number of data packets, a pause signal is transmitted to the ADSL modem. The pause signal inhibits further transmission of data packets to the ADSL modem on the ADSL channel until space is available in the second+buffer. When a pause signal is received from the ADSL modem, transmission of data packets to the ADSL modem is inhibited.
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  • Multiplexed subcarrier control in wavelength division multiplexed broadband networks

    In a wavelength division multiplexed network having a plurality of nodes and having optical channels at wavelengths .lambda.i, where i=1 . . . N, for transmission of optical signals over optical interconnection means, control for informing the network of which nodes are transmitting at which frequencies and for token holding. Control is provided without the need for a second transmitter at each node and another control channel. Data signals are provided at baseband by keying the optical signal at a data repetition rate. Control signals are imposed on a wavelength .lambda.t of a transmitting node as a subcarrier. Receiver means at each node respond to a .lambda.t from another channel to receive information. The node also includes means for all wavelengths .lambda.i and demodulating the subcarrier therefrom to derive control information. Means are provided for producing controls signals each corresponding to a channel and formatting the serial control sequence so that the data rate for control information does not increase as a function of network traffic.
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  • Acknowledgement using subcarrier multiplexed tones

    Subcarrier multiplexed acknowledgment tones are used for contention recovery in multiple-access WDM networks with basedband data packets and subcarrier multiplexed control headers. Upon receiving a data message from another node, the receiving node sends a subcarrier acknowledgement tone to the transmitter thus informing the transmitting node that the message has been received. The thoughput of the network is significantly improved. In an alternative embodiment, an acknowledgement is sent from the receiver by impressing a data message on a subcarrier.
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  • Triple-function semiconductor laser amplifier

    An optoelectronic device is disclosed utilizing a semiconductor laser amplifier that provides for simultaneous detection, amplification, and modulation of an input optical signal. In one embodiment, an electronic transmitter and receiver are coupled to the semiconductor laser amplifier through an RF circulator. In an alternative embodiment, the electronic transmitter and receiver are coupled to the semiconductor laser amplifier through an RF power splitter with frequency or phase discriminating circuitry.
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  • Articulated rider roll system and method

    A rider roll system for exerting an even nip load force along the surface of a roll of paper being wound from a continuous on-coming web in a winder comprises a plurality of rider roll wheel elements, each of which is connected to a common source of hydraulic pressure to provide the same rolling nip force against the wound paper roll. The rider roll wheel elements are mounted to a beam which is translationally movable above the wound paper roll. The beam and individual rider roll wheel elements are moved upwardly as a function of the increase in the diameter of the wound paper roll. The relationship of the beam movement relative to the diameter of the wound paper roll is controlled by a programmable logic controller. The individual wheel elements are loaded against a counter-balance force so as to provide equal, but cushioned, nip force against the surface of the wound paper roll at short intervals along its length. The magnitude of the evenly applied nip load force is also controlled as a function of the wound paper roll diameter.
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  • Monolithically integrated optical amplifier and photodetector tap

    A semiconductor optical amplifier with a high speed photodetector acting as an optical tap is disclosed. The device functions simultaneously as an in-line optical amplifier and as a high-speed photodetector tap. An in-line an optical amplifier is combined with a waveguiding, high speed (low capacitance) reverse-biased photodetector that absorbs only a percentage of the amplified signal, allowing the remainder to pass through without distortion.
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  • Wideband optical amplifier-receiver system

    A semiconductor optical amplifier is utilized for optical amplification and for detection of an optical signal at the current injection electrode of the optical amplifier. A wide detection bandwidth is provided by utilizing an impedance transformer between the current injection terminal and the detection circuit. The impedance transformer typically has an input impedance of about 1 to 15 ohms. The impedance transformer can be a bipolar junction transistor circuit, a microstrip transmission line impedance transformer or a hybrid impedance transformer. A wide detection bandwidth is also obtained by providing a semiconductor optical amplifier having two current injection electrodes. A bias current is supplied through both current injection electrodes, and both electrodes produce optical gain. However, only one of the electrodes is used for optical signal detection. The detection electrode has a relatively high junction resistance and a relatively high series resistance.
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  • Quadrature optical phase modulators for lightwave systems

    Optical communication methods and apparatus are disclosed for transmitting two or more optical signals with different optical carrier frequencies on a single optical fiber with high spectral efficiency. Each optical carrier is typically modulated with multiple modulated subcarriers. In one embodiment, an optical phase modulator provides cancellation of second order intermodulation products in each optical signal, thereby permitting the optical carrier frequencies to be spaced by 2f.sub.max, where f.sub.max is the maximum modulation frequency. In another embodiment, a single sideband optical phase modulator provides cancellation of second order intermodulation products and one signal sideband, thereby permitting the optical carrier frequencies to be spaced by f.sub.max. Quadrature optical phase modulators for simultaneous transmission of two independent baseband digital data signals or two independent subcarrier multiplexed signals are disclosed.
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  • Optical signal equalizer for wavelength division multiplexed optical fiber systems

    This invention disclosure describes the application of a polarization insensitive acoustically-tuned optical filter used in a multichannel WDM system to equalize variations in the power level of the WDM channels. The invention also describes a simple means for providing a low frequency control system which enables the equalizer to determine the signal levels of N optical carriers prior to equalizing the signals.
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