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Sample records for access channel mac

  1. PAD-MAC: Primary User Activity-Aware Distributed MAC for Multi-Channel Cognitive Radio Networks

    PubMed Central

    Ali, Amjad; Piran, Md. Jalil; Kim, Hansoo; Yun, Jihyeok; Suh, Doug Young

    2015-01-01

    Cognitive radio (CR) has emerged as a promising technology to solve problems related to spectrum scarcity and provides a ubiquitous wireless access environment. CR-enabled secondary users (SUs) exploit spectrum white spaces opportunistically and immediately vacate the acquired licensed channels as primary users (PUs) arrive. Accessing the licensed channels without the prior knowledge of PU traffic patterns causes severe throughput degradation due to excessive channel switching and PU-to-SU collisions. Therefore, it is significantly important to design a PU activity-aware medium access control (MAC) protocol for cognitive radio networks (CRNs). In this paper, we first propose a licensed channel usage pattern identification scheme, based on a two-state Markov model, and then estimate the future idle slots using previous observations of the channels. Furthermore, based on these past observations, we compute the rank of each available licensed channel that gives SU transmission success assessment during the estimated idle slot. Secondly, we propose a PU activity-aware distributed MAC (PAD-MAC) protocol for heterogeneous multi-channel CRNs that selects the best channel for each SU to enhance its throughput. PAD-MAC controls SU activities by allowing them to exploit the licensed channels only for the duration of estimated idle slots and enables predictive and fast channel switching. To evaluate the performance of the proposed PAD-MAC, we compare it with the distributed QoS-aware MAC (QC-MAC) and listen-before-talk MAC schemes. Extensive numerical results show the significant improvements of the PAD-MAC in terms of the SU throughput, SU channel switching rate and PU-to-SU collision rate. PMID:25831084

  2. PAD-MAC: primary user activity-aware distributed MAC for multi-channel cognitive radio networks.

    PubMed

    Ali, Amjad; Piran, Md Jalil; Kim, Hansoo; Yun, Jihyeok; Suh, Doug Young

    2015-01-01

    Cognitive radio (CR) has emerged as a promising technology to solve problems related to spectrum scarcity and provides a ubiquitous wireless access environment. CR-enabled secondary users (SUs) exploit spectrum white spaces opportunistically and immediately vacate the acquired licensed channels as primary users (PUs) arrive. Accessing the licensed channels without the prior knowledge of PU traffic patterns causes severe throughput degradation due to excessive channel switching and PU-to-SU collisions. Therefore, it is significantly important to design a PU activity-aware medium access control (MAC) protocol for cognitive radio networks (CRNs). In this paper, we first propose a licensed channel usage pattern identification scheme, based on a two-state Markov model, and then estimate the future idle slots using previous observations of the channels. Furthermore, based on these past observations, we compute the rank of each available licensed channel that gives SU transmission success assessment during the estimated idle slot. Secondly, we propose a PU activity-aware distributed MAC (PAD-MAC) protocol for heterogeneous multi-channel CRNs that selects the best channel for each SU to enhance its throughput. PAD-MAC controls SU activities by allowing them to exploit the licensed channels only for the duration of estimated idle slots and enables predictive and fast channel switching. To evaluate the performance of the proposed PAD-MAC, we compare it with the distributed QoS-aware MAC (QC-MAC) and listen-before-talk MAC schemes. Extensive numerical results show the significant improvements of the PAD-MAC in terms of the SU throughput, SU channel switching rate and PU-to-SU collision rate. PMID:25831084

  3. Managed Access by Controlled Sensing (MACS)

    SciTech Connect

    Curtiss, J.A.; Indusi, J.P.

    1994-08-01

    During chemical weapons challenge inspections, the CWC treaty allows ``alternate means`` of access to be proposed by the nation challenged. BNL`s Safeguards, Safety and Nonproliferation Division is funded by the Defense Nuclear Agency to develop a system to provide the challenge inspection team with a ``virtual presence`` within the facility while denying personal access. A general purpose configuration of a mobile station manned by site personnel and a base station manned by the challenge inspector, supported by a flexible communication system, will allow facility personnel to tailor the basic model to their site. Design of the MACS system is based on maximum use of commercial equipment that is available on the international market. Design requirements for the MACS system include methods of establishing geographical position, distance measuring equipment for use in verifying dimensions on floor plans, video and two-way audio links between the mobile unit and the base station, and portability and versatility of the equipment. The MACS platform will also support deployment of selected instrumentation which the site may offer to the challenge inspection team. This paper describes the design and construction of the prototype MACS system.

  4. Handling Deafness Problem of Scheduled Multi-Channel Polling MACs

    NASA Astrophysics Data System (ADS)

    Jiang, Fulong; Liu, Hao; Shi, Longxing

    Combining scheduled channel polling with channel diversity is a promising way for a MAC protocol to achieve high energy efficiency and performance under both light and heavy traffic conditions. However, the deafness problem may cancel out the benefit of channel diversity. In this paper, we first investigate the deafness problem of scheduled multi-channel polling MACs with experiments. Then we propose and evaluate two schemes to handle the deafness problem. Our experiment shows that deafness is a significant reason for performance degradation in scheduled multi-channel polling MACs. A proper scheme should be chosen depending on the traffic pattern and the design objective.

  5. IDMA-Based MAC Protocol for Satellite Networks with Consideration on Channel Quality

    PubMed Central

    2014-01-01

    In order to overcome the shortcomings of existing medium access control (MAC) protocols based on TDMA or CDMA in satellite networks, interleave division multiple access (IDMA) technique is introduced into satellite communication networks. Therefore, a novel wide-band IDMA MAC protocol based on channel quality is proposed in this paper, consisting of a dynamic power allocation algorithm, a rate adaptation algorithm, and a call admission control (CAC) scheme. Firstly, the power allocation algorithm combining the technique of IDMA SINR-evolution and channel quality prediction is developed to guarantee high power efficiency even in terrible channel conditions. Secondly, the effective rate adaptation algorithm, based on accurate channel information per timeslot and by the means of rate degradation, can be realized. What is more, based on channel quality prediction, the CAC scheme, combining the new power allocation algorithm, rate scheduling, and buffering strategies together, is proposed for the emerging IDMA systems, which can support a variety of traffic types, and offering quality of service (QoS) requirements corresponding to different priority levels. Simulation results show that the new wide-band IDMA MAC protocol can make accurate estimation of available resource considering the effect of multiuser detection (MUD) and QoS requirements of multimedia traffic, leading to low outage probability as well as high overall system throughput. PMID:25126592

  6. IDMA-based MAC protocol for satellite networks with consideration on channel quality.

    PubMed

    Liu, Gongliang; Fang, Xinrui; Kang, Wenjing

    2014-01-01

    In order to overcome the shortcomings of existing medium access control (MAC) protocols based on TDMA or CDMA in satellite networks, interleave division multiple access (IDMA) technique is introduced into satellite communication networks. Therefore, a novel wide-band IDMA MAC protocol based on channel quality is proposed in this paper, consisting of a dynamic power allocation algorithm, a rate adaptation algorithm, and a call admission control (CAC) scheme. Firstly, the power allocation algorithm combining the technique of IDMA SINR-evolution and channel quality prediction is developed to guarantee high power efficiency even in terrible channel conditions. Secondly, the effective rate adaptation algorithm, based on accurate channel information per timeslot and by the means of rate degradation, can be realized. What is more, based on channel quality prediction, the CAC scheme, combining the new power allocation algorithm, rate scheduling, and buffering strategies together, is proposed for the emerging IDMA systems, which can support a variety of traffic types, and offering quality of service (QoS) requirements corresponding to different priority levels. Simulation results show that the new wide-band IDMA MAC protocol can make accurate estimation of available resource considering the effect of multiuser detection (MUD) and QoS requirements of multimedia traffic, leading to low outage probability as well as high overall system throughput. PMID:25126592

  7. An energy-efficient rate adaptive media access protocol (RA-MAC) for long-lived sensor networks.

    PubMed

    Hu, Wen; Chen, Quanjun; Corke, Peter; O'Rourke, Damien

    2010-01-01

    We introduce an energy-efficient Rate Adaptive Media Access Control (RA-MAC) algorithm for long-lived Wireless Sensor Networks (WSNs). Previous research shows that the dynamic and lossy nature of wireless communications is one of the major challenges to reliable data delivery in WSNs. RA-MAC achieves high link reliability in such situations by dynamically trading off data rate for channel gain. The extra gain that can be achieved reduces the packet loss rate which contributes to reduced energy expenditure through a reduced numbers of retransmissions. We achieve this at the expense of raw bit rate which generally far exceeds the application's link requirement. To minimize communication energy consumption, RA-MAC selects the optimal data rate based on the estimated link quality at each data rate and an analytical model of the energy consumption. Our model shows how the selected data rate depends on different channel conditions in order to minimize energy consumption. We have implemented RA-MAC in TinyOS for an off-the-shelf sensor platform (the TinyNode) on top of a state-of-the-art WSN Media Access Control Protocol, SCP-MAC, and evaluated its performance by comparing our implementation with the original SCP-MAC using both simulation and experiment. PMID:22219675

  8. An Energy-efficient Rate Adaptive Media Access Protocol (RA-MAC) for Long-lived Sensor Networks

    PubMed Central

    Hu, Wen; Chen, Quanjun; Corke, Peter; O’Rourke, Damien

    2010-01-01

    We introduce an energy-efficient Rate Adaptive Media Access Control (RA-MAC) algorithm for long-lived Wireless Sensor Networks (WSNs). Previous research shows that the dynamic and lossy nature of wireless communications is one of the major challenges to reliable data delivery in WSNs. RA-MAC achieves high link reliability in such situations by dynamically trading off data rate for channel gain. The extra gain that can be achieved reduces the packet loss rate which contributes to reduced energy expenditure through a reduced numbers of retransmissions. We achieve this at the expense of raw bit rate which generally far exceeds the application’s link requirement. To minimize communication energy consumption, RA-MAC selects the optimal data rate based on the estimated link quality at each data rate and an analytical model of the energy consumption. Our model shows how the selected data rate depends on different channel conditions in order to minimize energy consumption. We have implemented RA-MAC in TinyOS for an off-the-shelf sensor platform (the TinyNode) on top of a state-of-the-art WSN Media Access Control Protocol, SCP-MAC, and evaluated its performance by comparing our implementation with the original SCP-MAC using both simulation and experiment. PMID:22219675

  9. Adaptive MAC-layer protocol for multiservice digital access via tree and branch communication networks

    NASA Astrophysics Data System (ADS)

    Kotikalapudi, Sriram; Li, Chia-Chang; Magill, Peter D.; Whitaker, Norman A.; Dail, James E.; Dajer, Miguel A.; Siller, Curtis A., Jr.

    1995-11-01

    Described here is an adaptive MAC-layer protocol that supports multiservice (STM and ATM) applications in the context of subscriber access to tree and branch (e.g., fiber-coaxial cable) networks. The protocol adapts to changing demands for a mix of circuit and cell mode applications, and efficiently allocates upstream and downstream bandwidth to a variety of bursty and isochronous traffic sources. In the case of a hybrid fiber-coaxial (HFC) network the protocol resides in customer premises equipment and a common head-end controller. A medium-access control (MAC) processor provides for dividing the time domain for a given digital bitstream into successive frames, each with multiple STM and ATM time slots. Within the STM region of a frame, variable length time slots are allocated to calls (e.g., telephony, video telephony) requiring different amounts of bandwidth. A contention access signaling channel is also provided in this region for call control and set-up requests. Within the ATM region fixed-length time slots accommodate one individual ATM cell. These ATM time slots may be reserved for a user for the duration of a call or burst of successive ATM cells, or shared via a contention process. At least one contention time slot is available for signaling messages related to ATM call control and set-up requests. Further, the fixed-length ATM time slots may be reserved by a user for the duration of a call, or shared through a contention process. This paper describes the MAC-layer protocol, its relation to circuit- and ATM- amenable applications, and its performance with respect to signaling throughput and latency, and bandwidth efficiency for several service scenarios.

  10. Quantum superadditivity in linear optics networks: Sending bits via multiple-access Gaussian channels

    SciTech Connect

    Czekaj, L.; Horodecki, P.; Korbicz, J. K.; Chhajlany, R. W.

    2010-08-15

    Superadditivity effects of communication capacities are known in the case of discrete variable quantum channels. We describe the continuous variable analog of one of these effects in the framework of Gaussian multiple access channels (MACs). Classically, superadditivity-type effects are strongly restricted: For example, adding resources to one sender is never advantageous to other senders in sending their respective information to the receiver. We show that this rule can be surpassed using quantum resources, giving rise to a type of truly quantum superadditivity. This is illustrated here for two examples of experimentally feasible Gaussian MACs.

  11. A Novel Multi-Channel MAC Protocol for Cluster Based Wireless Multimedia Sensor Networks

    NASA Astrophysics Data System (ADS)

    Wei, Lu; Longmei, Zhang

    An energy efficient, scalable and collision free MAC protocol, DTFMM, is presented in this paper, which combines frequency and time division principles for medium sharing. It is based on clustered network topology, and the protocol employs a distributed local coordinate algorithm for assigning channels among clusters to enable simultaneous non-interfering data collection. Intra-cluster transmissions are scheduled by cluster head (CH) based on time slot. CHs aggregate the gathered data and forward it over inter-CH paths to the base-station based on minimum spanning tree routing. Distinct channels are adopted by the independent branches of the inter-CH routing tree. Data transmission on a branch is further scheduled in depth-first ordering. DTFMM allows nodes to stay in sleeping mode for the longest duration and thus it minimizes energy consumption. Simulation demonstrated superiority of DTFMM in terms of convergent rate, throughput and delay performance when compared with well-known protocol MMSN.

  12. Multiple-access channels without synchronization

    NASA Technical Reports Server (NTRS)

    Mceliece, R. J.; Posner, E. C.

    1977-01-01

    This paper discusses models for multiple-access communications which take into account the fact that the channel users may not be able to synchronize their transmissions. It is shown that for a broad class of such channels, the capacity region is the same as it would be with user synchronization. Some open problems are discussed.

  13. Multichannel MAC Layer In Mobile Ad—Hoc Network

    NASA Astrophysics Data System (ADS)

    Logesh, K.; Rao, Samba Siva

    2010-11-01

    This paper we presented the design objectives and technical challenges in Multichannel MAC protocols in Mobile Ad-hoc Network. In IEEE 802.11 a/b/g standards allow use of multiple channels, only a single channel is popularly used, due to the lack of efficient protocols that enable use of Multiple Channels. Even though complex environments in ad hoc networks require a combined control of physical (PHY) and medium access control (MAC) layers resources in order to optimize performance. And also we discuss the characteristics of cross-layer frame and give a multichannel MAC approach.

  14. 47 CFR 76.701 - Leased access channels.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Leased access channels. 76.701 Section 76.701... CABLE TELEVISION SERVICE Cable Television Access § 76.701 Leased access channels. (a) Notwithstanding 47... leased access program or portion of a leased access program that the operator reasonably...

  15. 47 CFR 76.701 - Leased access channels.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Leased access channels. 76.701 Section 76.701 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Cable Television Access § 76.701 Leased access channels. (a) Notwithstanding...

  16. Distributed reservation control protocols for random access broadcasting channels

    NASA Technical Reports Server (NTRS)

    Greene, E. P.; Ephremides, A.

    1981-01-01

    Attention is given to a communication network consisting of an arbitrary number of nodes which can communicate with each other via a time-division multiple access (TDMA) broadcast channel. The reported investigation is concerned with the development of efficient distributed multiple access protocols for traffic consisting primarily of single packet messages in a datagram mode of operation. The motivation for the design of the protocols came from the consideration of efficient multiple access utilization of moderate to high bandwidth (4-40 Mbit/s capacity) communication satellite channels used for the transmission of short (1000-10,000 bits) fixed length packets. Under these circumstances, the ratio of roundtrip propagation time to packet transmission time is between 100 to 10,000. It is shown how a TDMA channel can be adaptively shared by datagram traffic and constant bandwidth users such as in digital voice applications. The distributed reservation control protocols described are a hybrid between contention and reservation protocols.

  17. Proportional Data Rate Fairness Resource Allocation for MIMO-OFDM Multiple Access Channel by Considering the Correlation Effect of Line of Sight and Non Line of Sight Channel Conditions

    NASA Astrophysics Data System (ADS)

    Maung, Sann Maw; Sasase, Iwao

    In the MIMO-OFDM multiple access channel (MIMO-OFDM-MAC) uplink scenario, the base station decides the uplink parameters for multiple users based on channel state information (CSI) from each user in the system. The performance of MIMO-OFDM-MAC systems can be significantly improved by using an adaptive transmission and resource allocation schemes which consider the correlation effect of line of sight (LOS) and non line of sight (NLOS) channel conditions for different users in the system. A lot of papers have been published on resource allocation schemes for MIMO-OFDM systems. However, most of these resource allocation schemes have been considered for MIMO-OFDMA systems, where users are separated in the frequency domain and each user uses the same uplink and downlink channels in the same channel conditions. On the other hand, in the mulituser MIMO-OFDM systems, more than one user can be assigned the same frequency and channel conditions for the MIMO-OFDM broadcast channel (downlink) and MIMO-OFDM-MAC channel (uplink) are not the same. Therefore, the same resource allocation schemes for the conventional MIMO-OFDM systems can not be applied to multiuser MIMO-OFDM systems with different uplink and downlink channel conditions. Until now, most of the resource allocation schemes have been considered only for downlink MIMO-OFDM broadcast (MIMO-OFDM-BC) channel and very few papers tackle the fairness among users. Moreover, no paper considers a scheme to realize proportional data rate fairness among users in the MIMO-OFDM-MAC condition. In this paper, we propose a proportional data rate fairness resource allocation scheme with adaptive bit loading for MIMO-ODFM-MAC systems by considering the correlation effects of LOS and NLOS channel conditions in both spatial and frequency domains. Computer simulation results show that the proposed scheme can give larger system capacity while maintaining the proportional data rate fairness requirements among users in the system under the

  18. CoR-MAC: Contention over Reservation MAC Protocol for Time-Critical Services in Wireless Body Area Sensor Networks.

    PubMed

    Yu, Jeongseok; Park, Laihyuk; Park, Junho; Cho, Sungrae; Keum, Changsup

    2016-01-01

    Reserving time slots for urgent data, such as life-critical information, seems to be very attractive to guarantee their deadline requirements in wireless body area sensor networks (WBASNs). On the other hand, this reservation imposes a negative impact on performance for the utilization of a channel. This paper proposes a new channel access scheme referred to as the contention over reservation MAC (CoR-MAC) protocol for time-critical services in wireless body area sensor networks. CoR-MAC uses the dual reservation; if the reserved time slots are known to be vacant, other nodes can access the time slots by contention-based reservation to maximize the utilization of a channel and decrease the delay of the data. To measure the effectiveness of the proposed scheme against IEEE 802.15.4 and IEEE 802.15.6, we evaluated their performances with various performance indexes. The CoR-MAC showed 50% to 850% performance improvement in terms of the delay of urgent and time-critical data according to the number of nodes. PMID:27171085

  19. CoR-MAC: Contention over Reservation MAC Protocol for Time-Critical Services in Wireless Body Area Sensor Networks

    PubMed Central

    Yu, Jeongseok; Park, Laihyuk; Park, Junho; Cho, Sungrae; Keum, Changsup

    2016-01-01

    Reserving time slots for urgent data, such as life-critical information, seems to be very attractive to guarantee their deadline requirements in wireless body area sensor networks (WBASNs). On the other hand, this reservation imposes a negative impact on performance for the utilization of a channel. This paper proposes a new channel access scheme referred to as the contention over reservation MAC (CoR-MAC) protocol for time-critical services in wireless body area sensor networks. CoR-MAC uses the dual reservation; if the reserved time slots are known to be vacant, other nodes can access the time slots by contention-based reservation to maximize the utilization of a channel and decrease the delay of the data. To measure the effectiveness of the proposed scheme against IEEE 802.15.4 and IEEE 802.15.6, we evaluated their performances with various performance indexes. The CoR-MAC showed 50% to 850% performance improvement in terms of the delay of urgent and time-critical data according to the number of nodes. PMID:27171085

  20. Modes of Access: The Influence of Dissemination Channels on the Use of Open Access Monographs

    ERIC Educational Resources Information Center

    Snijder, Ronald

    2014-01-01

    Introduction: This paper studies the effects of several dissemination channels in an open access environment by analysing the download data of the OAPEN Library. Method: Download data were obtained containing the number of downloads and the name of the Internet provider. Based on public information, each Internet provider was categorised. The…

  1. A Priority-Based Adaptive MAC Protocol for Wireless Body Area Networks

    PubMed Central

    Bhandari, Sabin; Moh, Sangman

    2016-01-01

    In wireless body area networks (WBANs), various sensors and actuators are placed on/inside the human body and connected wirelessly. WBANs have specific requirements for healthcare and medical applications, hence, standard protocols like the IEEE 802.15.4 cannot fulfill all the requirements. Consequently, many medium access control (MAC) protocols, mostly derived from the IEEE 802.15.4 superframe structure, have been studied. Nevertheless, they do not support a differentiated quality of service (QoS) for the various forms of traffic coexisting in a WBAN. In particular, a QoS-aware MAC protocol is essential for WBANs operating in the unlicensed Industrial, Scientific, and Medical (ISM) bands, because different wireless services like Bluetooth, WiFi, and Zigbee may coexist there and cause severe interference. In this paper, we propose a priority-based adaptive MAC (PA-MAC) protocol for WBANs in unlicensed bands, which allocates time slots dynamically, based on the traffic priority. Further, multiple channels are effectively utilized to reduce access delays in a WBAN, in the presence of coexisting systems. Our performance evaluation results show that the proposed PA-MAC outperforms the IEEE 802.15.4 MAC and the conventional priority-based MAC in terms of the average transmission time, throughput, energy consumption, and data collision ratio. PMID:26999162

  2. A Priority-Based Adaptive MAC Protocol for Wireless Body Area Networks.

    PubMed

    Bhandari, Sabin; Moh, Sangman

    2016-01-01

    In wireless body area networks (WBANs), various sensors and actuators are placed on/inside the human body and connected wirelessly. WBANs have specific requirements for healthcare and medical applications, hence, standard protocols like the IEEE 802.15.4 cannot fulfill all the requirements. Consequently, many medium access control (MAC) protocols, mostly derived from the IEEE 802.15.4 superframe structure, have been studied. Nevertheless, they do not support a differentiated quality of service (QoS) for the various forms of traffic coexisting in a WBAN. In particular, a QoS-aware MAC protocol is essential for WBANs operating in the unlicensed Industrial, Scientific, and Medical (ISM) bands, because different wireless services like Bluetooth, WiFi, and Zigbee may coexist there and cause severe interference. In this paper, we propose a priority-based adaptive MAC (PA-MAC) protocol for WBANs in unlicensed bands, which allocates time slots dynamically, based on the traffic priority. Further, multiple channels are effectively utilized to reduce access delays in a WBAN, in the presence of coexisting systems. Our performance evaluation results show that the proposed PA-MAC outperforms the IEEE 802.15.4 MAC and the conventional priority-based MAC in terms of the average transmission time, throughput, energy consumption, and data collision ratio. PMID:26999162

  3. Intrathecal Veratridine Administration Increases MAC in Rats

    PubMed Central

    Zhang, Yi; Sharma, Manohar; Eger, Edmond I; Laster, Michael J.; Hemmings, Hugh C.; Harris, R. Adron

    2008-01-01

    Background Results from several studies point to sodium channels as potential mediators of the immobility produced by inhaled anesthetics. We hypothesized that the intrathecal administration of veratridine, a drug that enhances the activity or effect of sodium channels, should increase MAC. Methods We measured the change in isoflurane MAC caused by intrathecal infusion of various concentrations of veratridine into the lumbothoracic subarachnoid space of rats. We compared these result to those obtained from intracerebroventricular infusion. Results As predicted, intrathecal infusion of veratridine increased MAC. The greatest infused concentration (25 μM) also produced neuronal injury in the hind limbs of two rats and decreased the peak effect on MAC. A concentration of 1.6 μM produced the greatest (21%) increase in MAC. Intraventricular infusion of 1.6 and 6.4 μM veratridine did not alter MAC. Rats given 25 μM died. Conclusion Intrathecal administration of veratradine increases MAC of isoflurane, a finding consistent with a role for sodium channels as potential mediators of the immobility produced by inhaled anesthetics. Implications Intrathecal administration of veratridine can increase MAC, presumably by an effect on sodium channels. PMID:18713899

  4. A hybrid path-oriented code assignment CDMA-based MAC protocol for underwater acoustic sensor networks.

    PubMed

    Chen, Huifang; Fan, Guangyu; Xie, Lei; Cui, Jun-Hong

    2013-01-01

    Due to the characteristics of underwater acoustic channel, media access control (MAC) protocols designed for underwater acoustic sensor networks (UWASNs) are quite different from those for terrestrial wireless sensor networks. Moreover, in a sink-oriented network with event information generation in a sensor field and message forwarding to the sink hop-by-hop, the sensors near the sink have to transmit more packets than those far from the sink, and then a funneling effect occurs, which leads to packet congestion, collisions and losses, especially in UWASNs with long propagation delays. An improved CDMA-based MAC protocol, named path-oriented code assignment (POCA) CDMA MAC (POCA-CDMA-MAC), is proposed for UWASNs in this paper. In the proposed MAC protocol, both the round-robin method and CDMA technology are adopted to make the sink receive packets from multiple paths simultaneously. Since the number of paths for information gathering is much less than that of nodes, the length of the spreading code used in the POCA-CDMA-MAC protocol is shorter greatly than that used in the CDMA-based protocols with transmitter-oriented code assignment (TOCA) or receiver-oriented code assignment (ROCA). Simulation results show that the proposed POCA-CDMA-MAC protocol achieves a higher network throughput and a lower end-to-end delay compared to other CDMA-based MAC protocols. PMID:24193100

  5. Unsynchronized Energy-Efficient Medium Access Control and Routing in Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Hurni, Philipp

    This master thesis investigates optimizations on recently proposed fully unsynchronized power saving sensor MAC protocols. In contrast to many other sensor MAC protocols, unsynchronized sensor MAC protocols renounce on any kind of network- or cluster-wide synchronization for channel access coordination and maintenance of a common wake-sleep pattern, because in wireless sensor networks with low traffic requirements, the overhead for maintaining synchronization is likely to exceed the energy spent for the actual data traffic.

  6. News and Information on Community Access Channels: Market Concerns amidst the Marketplace of Ideas.

    ERIC Educational Resources Information Center

    Atkin, David; LaRose, Robert

    Utilizing a regionally diversified sample of cable viewers to investigate viewer patronage of community channels--defined to include public, educational, and government (PEG) access as well as community (or leased) access channels, a study examined a quarterly national survey of homes serviced by cable in the United States. Each quarter, 1,000…

  7. Multi-channel access technology based on wavelength division multiplexing in wireless UV communication mesh network

    NASA Astrophysics Data System (ADS)

    Zhao, Tai-fei; Zhang, Ai-li; Xue, Rong-li

    2013-05-01

    In this paper, the multi-channel access technology of wavelength division multiplexing (WDM) in the wireless ultraviolet (UV) scattering communication is studied. A multi-interface and multi-channel device is deployed in each UV transceiver node. The band-pass filter is configured in the receiving node so as to realize the multi-channel access by use of the UV WDM technology. Both the UV communication node model and the UV channel model are established. Three types of UV no-line-of-sight (NLOS) multi-channel communications are simulated in the mesh topologies with NS2. The results show that the UV multi-channel access technology can increase network throughput effectively with using WDM.

  8. MACS as a tool for international inspections

    SciTech Connect

    Curtiss, J.A.; Indusi, J.P.

    1995-08-01

    The MACS/ACRS (Managed Access by Controlled Sensing/Access by Controlled Remote Sensing) system is a collection of communication devices, video capability, and distance-measuring equipment which can effectively substitute for the physical presence of a challenge inspector within a facility. The MACS design allows growth of the prototype, developed in response to the Chemical Weapons Convention (CWC), into a versatile device for inspection of sensitive nuclear facilities under other international arrangements, for example the proposed Fissile Material Cutoff Convention. A MACS/ACRS-type system in a standard, international-recognized configuration could resolve sensitive information and safety concerns through providing a means of achieving the goals of an inspection while excluding the inspector. We believe the technology used to develop MACS for the Defense Nuclear Agency, followed by ACRS for the Department of Energy, is universally adaptable for minimally-intrusive managed-access international inspections of sensitive sites.

  9. Mycobacterium Avium Complex (MAC)

    MedlinePlus

    ... MAC? The symptoms of MAC can include high fevers, chills, diarrhea , weight loss, stomach aches, fatigue, and anemia ( ... anemia. Many drug interactions. Rifampin (Rifampicin, Rifadin, Rimactane): fever, chills, muscle or bone pain; can turn urine, sweat, ...

  10. Intelligent Cooperative MAC Protocol for Balancing Energy Consumption

    NASA Astrophysics Data System (ADS)

    Wu, S.; Liu, K.; Huang, B.; Liu, F.

    To extend the lifetime of wireless sensor networks, we proposed an intelligent balanced energy consumption cooperative MAC protocol (IBEC-CMAC) based on the multi-node cooperative transmission model. The protocol has priority to access high-quality channels for reducing energy consumption of each transmission. It can also balance the energy consumption among cooperative nodes by using high residual energy nodes instead of excessively consuming some node's energy. Simulation results show that IBEC-CMAC can obtain longer network lifetime and higher energy utilization than direct transmission.

  11. Modeling C-Band Co-Channel Interference From AeroMACS Omni-Directional Antennas to Mobile Satellite Service Feeder Uplinks

    NASA Technical Reports Server (NTRS)

    Wilson, Jeffrey D.

    2011-01-01

    A new C-band (5091 to 5150 MHz) airport communications system designated as Aeronautical Mobile Airport Communications System (AeroMACS) is being planned under the Federal Aviation Administration s NextGen program. An interference analysis software program, Visualyse Professional (Transfinite Systems Ltd), is being utilized to provide guidelines on limitations for AeroMACS transmitters to avoid interference with other systems. A scenario consisting of a single omni-directional transmitting antenna at each of the major contiguous United States airports is modeled and the steps required to build the model are reported. The results are shown to agree very well with a previous study.

  12. CCSDS Advanced Orbiting Systems Virtual Channel Access Service for QoS MACHETE Model

    NASA Technical Reports Server (NTRS)

    Jennings, Esther H.; Segui, John S.

    2011-01-01

    To support various communications requirements imposed by different missions, interplanetary communication protocols need to be designed, validated, and evaluated carefully. Multimission Advanced Communications Hybrid Environment for Test and Evaluation (MACHETE), described in "Simulator of Space Communication Networks" (NPO-41373), NASA Tech Briefs, Vol. 29, No. 8 (August 2005), p. 44, combines various tools for simulation and performance analysis of space networks. The MACHETE environment supports orbital analysis, link budget analysis, communications network simulations, and hardware-in-the-loop testing. By building abstract behavioral models of network protocols, one can validate performance after identifying the appropriate metrics of interest. The innovators have extended the MACHETE model library to include a generic link-layer Virtual Channel (VC) model supporting quality-of-service (QoS) controls based on IP streams. The main purpose of this generic Virtual Channel model addition was to interface fine-grain flow-based QoS (quality of service) between the network and MAC layers of the QualNet simulator, a commercial component of MACHETE. This software model adds the capability of mapping IP streams, based on header fields, to virtual channel numbers, allowing extended QoS handling at link layer. This feature further refines the QoS v existing at the network layer. QoS at the network layer (e.g. diffserv) supports few QoS classes, so data from one class will be aggregated together; differentiating between flows internal to a class/priority is not supported. By adding QoS classification capability between network and MAC layers through VC, one maps multiple VCs onto the same physical link. Users then specify different VC weights, and different queuing and scheduling policies at the link layer. This VC model supports system performance analysis of various virtual channel link-layer QoS queuing schemes independent of the network-layer QoS systems.

  13. Fast arithmetic in MacLISP

    NASA Technical Reports Server (NTRS)

    Steele, G. L., Jr.

    1977-01-01

    MacLISP provides a compiler which produces numerical code competitive in speed with some FORTRAN implementations and yet compatible with the rest of the MacLISP system. All numerical programs can be run under the MacLISP interpreter. Additional declarations to the compiler specify type information which allows the generation of optimized numerical code which generally does not require the garbage collection of temporary numerical results. Array accesses are almost as fast as in FORTRAN, and permit the use of dynamically allocated arrays of varying dimensions. The implementation decisions regarding user interface, data representations, and interfacing conventions are discussed which allow the generation of fast numerical LISP code.

  14. State-dependent access of anions to the cystic fibrosis transmembrane conductance regulator chloride channel pore.

    PubMed

    Fatehi, Mohammad; Linsdell, Paul

    2008-03-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel is gated by intracellular factors; however, conformational changes in the channel pore associated with channel activation have not been identified. We have used patch clamp recording to investigate the state-dependent accessibility of substituted cysteine residues in the CFTR channel pore to a range of cysteine-reactive reagents applied to the extracellular side of the membrane. Using functional modification of the channel current-voltage relationship as a marker of modification, we find that several positively charged reagents are able to penetrate deeply into the pore from the outside irrespective of whether or not the channels have been activated. In contrast, access of three anionic cysteine-reactive reagents, the methanesulfonate sodium (2-sulfonatoethyl)methanesulfonate, the organic mercurial p-chloromercuriphenylsulfonic acid, and the permeant anion Au(CN)(2)(-), to several different sites in the pore is strictly limited prior to channel activation. This suggests that in nonactivated channels some ion selectivity mechanism exists to exclude anions yet permit cations into the channel pore from the extracellular solution. We suggest that activation of CFTR channels involves a conformational change in the pore that removes a strong selectivity against anion entry from the extracellular solution. We propose further that this conformational change occurs in advance of channel opening, suggesting that multiple distinct closed pore conformations exist. PMID:18167343

  15. An Adaptive Channel Access Method for Dynamic Super Dense Wireless Sensor Networks.

    PubMed

    Lei, Chunyang; Bie, Hongxia; Fang, Gengfa; Zhang, Xuekun

    2015-01-01

    Super dense and distributed wireless sensor networks have become very popular with the development of small cell technology, Internet of Things (IoT), Machine-to-Machine (M2M) communications, Vehicular-to-Vehicular (V2V) communications and public safety networks. While densely deployed wireless networks provide one of the most important and sustainable solutions to improve the accuracy of sensing and spectral efficiency, a new channel access scheme needs to be designed to solve the channel congestion problem introduced by the high dynamics of competing nodes accessing the channel simultaneously. In this paper, we firstly analyzed the channel contention problem using a novel normalized channel contention analysis model which provides information on how to tune the contention window according to the state of channel contention. We then proposed an adaptive channel contention window tuning algorithm in which the contention window tuning rate is set dynamically based on the estimated channel contention level. Simulation results show that our proposed adaptive channel access algorithm based on fast contention window tuning can achieve more than 95 % of the theoretical optimal throughput and 0 . 97 of fairness index especially in dynamic and dense networks. PMID:26633421

  16. An Adaptive Channel Access Method for Dynamic Super Dense Wireless Sensor Networks

    PubMed Central

    Lei, Chunyang; Bie, Hongxia; Fang, Gengfa; Zhang, Xuekun

    2015-01-01

    Super dense and distributed wireless sensor networks have become very popular with the development of small cell technology, Internet of Things (IoT), Machine-to-Machine (M2M) communications, Vehicular-to-Vehicular (V2V) communications and public safety networks. While densely deployed wireless networks provide one of the most important and sustainable solutions to improve the accuracy of sensing and spectral efficiency, a new channel access scheme needs to be designed to solve the channel congestion problem introduced by the high dynamics of competing nodes accessing the channel simultaneously. In this paper, we firstly analyzed the channel contention problem using a novel normalized channel contention analysis model which provides information on how to tune the contention window according to the state of channel contention. We then proposed an adaptive channel contention window tuning algorithm in which the contention window tuning rate is set dynamically based on the estimated channel contention level. Simulation results show that our proposed adaptive channel access algorithm based on fast contention window tuning can achieve more than 95% of the theoretical optimal throughput and 0.97 of fairness index especially in dynamic and dense networks. PMID:26633421

  17. An adaptive OFDMA-based MAC protocol for underwater acoustic wireless sensor networks.

    PubMed

    Khalil, Issa M; Gadallah, Yasser; Hayajneh, Mohammad; Khreishah, Abdallah

    2012-01-01

    Underwater acoustic wireless sensor networks (UAWSNs) have many applications across various civilian and military domains. However, they suffer from the limited available bandwidth of acoustic signals and harsh underwater conditions. In this work, we present an Orthogonal Frequency Division Multiple Access (OFDMA)-based Media Access Control (MAC) protocol that is configurable to suit the operating requirements of the underwater sensor network. The protocol has three modes of operation, namely random, equal opportunity and energy-conscious modes of operation. Our MAC design approach exploits the multi-path characteristics of a fading acoustic channel to convert it into parallel independent acoustic sub-channels that undergo flat fading. Communication between node pairs within the network is done using subsets of these sub-channels, depending on the configurations of the active mode of operation. Thus, the available limited bandwidth gets fully utilized while completely avoiding interference. We derive the mathematical model for optimal power loading and subcarrier selection, which is used as basis for all modes of operation of the protocol. We also conduct many simulation experiments to evaluate and compare our protocol with other Code Division Multiple Access (CDMA)-based MAC protocols. PMID:23012517

  18. An Adaptive OFDMA-Based MAC Protocol for Underwater Acoustic Wireless Sensor Networks

    PubMed Central

    Khalil, Issa M.; Gadallah, Yasser; Hayajneh, Mohammad; Khreishah, Abdallah

    2012-01-01

    Underwater acoustic wireless sensor networks (UAWSNs) have many applications across various civilian and military domains. However, they suffer from the limited available bandwidth of acoustic signals and harsh underwater conditions. In this work, we present an Orthogonal Frequency Division Multiple Access (OFDMA)-based Media Access Control (MAC) protocol that is configurable to suit the operating requirements of the underwater sensor network. The protocol has three modes of operation, namely random, equal opportunity and energy-conscious modes of operation. Our MAC design approach exploits the multi-path characteristics of a fading acoustic channel to convert it into parallel independent acoustic sub-channels that undergo flat fading. Communication between node pairs within the network is done using subsets of these sub-channels, depending on the configurations of the active mode of operation. Thus, the available limited bandwidth gets fully utilized while completely avoiding interference. We derive the mathematical model for optimal power loading and subcarrier selection, which is used as basis for all modes of operation of the protocol. We also conduct many simulation experiments to evaluate and compare our protocol with other Code Division Multiple Access (CDMA)-based MAC protocols. PMID:23012517

  19. Access channels and methanol binding site to the CaMn4 cluster in Photosystem II based on solvent accessibility simulations, with implications for substrate water access.

    PubMed

    Ho, Felix M; Styring, Stenbjörn

    2008-02-01

    Given the tightly packed environment of Photosystem II (PSII), channels are expected to exist within the protein to allow the movement of small molecules to and from the oxygen evolving centre. In this report, we calculate solvent contact surfaces from the PSII crystal structures to identify such access channels for methanol and water molecules. In a previous study of the effects of methanol on the EPR split S1-, S3-, and S0-signals [Su et al. (2006) Biochemistry 45, 7617-7627], we proposed that methanol binds to one and the same Mn ion in all S-states. We find here that while channels of methanol dimensions were able to make contact with the CaMn4 cluster, only 3Mn and 4Mn were accessible to methanol. Combining this observation with spectroscopic data in the literature, we propose that 3Mn is the ion to which methanol binds. Furthermore, by calculating solvent contact surfaces for water, we found analogous and more extensive water accessible channels within PSII. On the basis of their structure, orientation, and electrostatic properties, we propose functional assignments of these channels as passages for substrate water access to the CaMn4 cluster, and for the exit of O2 and H+ that are released during water oxidation. Finally, we discuss the possible existence of a gating mechanism for the control of substrate water access to the CaMn4 cluster, based on the observation of a gap within the channel system that is formed by Ca2+ and several mechanistically very significant residues in the vicinity of the cluster. PMID:17964532

  20. Energy-efficient boarder node medium access control protocol for wireless sensor networks.

    PubMed

    Razaque, Abdul; Elleithy, Khaled M

    2014-01-01

    This paper introduces the design, implementation, and performance analysis of the scalable and mobility-aware hybrid protocol named boarder node medium access control (BN-MAC) for wireless sensor networks (WSNs), which leverages the characteristics of scheduled and contention-based MAC protocols. Like contention-based MAC protocols, BN-MAC achieves high channel utilization, network adaptability under heavy traffic and mobility, and low latency and overhead. Like schedule-based MAC protocols, BN-MAC reduces idle listening time, emissions, and collision handling at low cost at one-hop neighbor nodes and achieves high channel utilization under heavy network loads. BN-MAC is particularly designed for region-wise WSNs. Each region is controlled by a boarder node (BN), which is of paramount importance. The BN coordinates with the remaining nodes within and beyond the region. Unlike other hybrid MAC protocols, BN-MAC incorporates three promising models that further reduce the energy consumption, idle listening time, overhearing, and congestion to improve the throughput and reduce the latency. One of the models used with BN-MAC is automatic active and sleep (AAS), which reduces the ideal listening time. When nodes finish their monitoring process, AAS lets them automatically go into the sleep state to avoid the idle listening state. Another model used in BN-MAC is the intelligent decision-making (IDM) model, which helps the nodes sense the nature of the environment. Based on the nature of the environment, the nodes decide whether to use the active or passive mode. This decision power of the nodes further reduces energy consumption because the nodes turn off the radio of the transceiver in the passive mode. The third model is the least-distance smart neighboring search (LDSNS), which determines the shortest efficient path to the one-hop neighbor and also provides cross-layering support to handle the mobility of the nodes. The BN-MAC also incorporates a semi

  1. Energy-Efficient Boarder Node Medium Access Control Protocol for Wireless Sensor Networks

    PubMed Central

    Razaque, Abdul; Elleithy, Khaled M.

    2014-01-01

    This paper introduces the design, implementation, and performance analysis of the scalable and mobility-aware hybrid protocol named boarder node medium access control (BN-MAC) for wireless sensor networks (WSNs), which leverages the characteristics of scheduled and contention-based MAC protocols. Like contention-based MAC protocols, BN-MAC achieves high channel utilization, network adaptability under heavy traffic and mobility, and low latency and overhead. Like schedule-based MAC protocols, BN-MAC reduces idle listening time, emissions, and collision handling at low cost at one-hop neighbor nodes and achieves high channel utilization under heavy network loads. BN-MAC is particularly designed for region-wise WSNs. Each region is controlled by a boarder node (BN), which is of paramount importance. The BN coordinates with the remaining nodes within and beyond the region. Unlike other hybrid MAC protocols, BN-MAC incorporates three promising models that further reduce the energy consumption, idle listening time, overhearing, and congestion to improve the throughput and reduce the latency. One of the models used with BN-MAC is automatic active and sleep (AAS), which reduces the ideal listening time. When nodes finish their monitoring process, AAS lets them automatically go into the sleep state to avoid the idle listening state. Another model used in BN-MAC is the intelligent decision-making (IDM) model, which helps the nodes sense the nature of the environment. Based on the nature of the environment, the nodes decide whether to use the active or passive mode. This decision power of the nodes further reduces energy consumption because the nodes turn off the radio of the transceiver in the passive mode. The third model is the least-distance smart neighboring search (LDSNS), which determines the shortest efficient path to the one-hop neighbor and also provides cross-layering support to handle the mobility of the nodes. The BN-MAC also incorporates a semi

  2. Introduction to MAC CRM training

    NASA Technical Reports Server (NTRS)

    Brown, Donald D.

    1987-01-01

    The author introduces the Military Airlift Command (MAC) and its mission. A brief history of Cockpit Resource Management (CRM) as it relates to MAC is given. He also states why MAC is currently interested in CRM.

  3. Method for Evaluation of Outage Probability on Random Access Channel in Mobile Communication Systems

    NASA Astrophysics Data System (ADS)

    Kollár, Martin

    2012-05-01

    In order to access the cell in all mobile communication technologies a so called random-access procedure is used. For example in GSM this is represented by sending the CHANNEL REQUEST message from Mobile Station (MS) to Base Transceiver Station (BTS) which is consequently forwarded as an CHANNEL REQUIRED message to the Base Station Controller (BSC). If the BTS decodes some noise on the Random Access Channel (RACH) as random access by mistake (so- called ‘phantom RACH') then it is a question of pure coincidence which èstablishment cause’ the BTS thinks to have recognized. A typical invalid channel access request or phantom RACH is characterized by an IMMEDIATE ASSIGNMENT procedure (assignment of an SDCCH or TCH) which is not followed by sending an ESTABLISH INDICATION from MS to BTS. In this paper a mathematical model for evaluation of the Power RACH Busy Threshold (RACHBT) in order to guaranty in advance determined outage probability on RACH is described and discussed as well. It focuses on Global System for Mobile Communications (GSM) however the obtained results can be generalized on remaining mobile technologies (ie WCDMA and LTE).

  4. Acrylic resin guide for locating the abutment screw access channel of cement-retained implant prostheses.

    PubMed

    Ahmed, Ayman; Maroulakos, Georgios; Garaicoa, Jorge

    2016-05-01

    Abutment screw loosening represents a common and challenging technical complication of cement-retained implant prostheses. This article describes the fabrication of a simple and accurate poly(methyl methacrylate) guide for identifying the location and angulation of the abutment screw access channel of a cement-retained implant prosthesis with a loosened abutment screw. PMID:26794698

  5. An upper bound for codes in a two-access binary erasure channel

    NASA Technical Reports Server (NTRS)

    Van Tilborg, H. C. A.

    1978-01-01

    A method for determining an upper bound for the size of a code for a two-access binary erasure channel is presented. For uniquely decodable codes, this bound gives a combinatorial proof of a result by Liao. Examples of the bound are given for codes with minimum distance 4.

  6. 77 FR 25106 - Special Local Regulations for Marine Events; Potomac River, National Harbor Access Channel, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-27

    ... notice regarding our public dockets in the January 17, 2008, issue of the Federal Register (73 FR 3316... River, National Harbor Access Channel, MD AGENCY: Coast Guard, DHS. ACTION: Notice of proposed... click ``SEARCH.'' Click on Open Docket Folder on the line associated with this rulemaking. You may...

  7. 77 FR 39630 - Special Local Regulations for Marine Events; Potomac River, National Harbor Access Channel, MD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-05

    ... Department of Homeland Security FR Federal Register NPRM Notice of Proposed Rulemaking A. Regulatory History... Federal Register (77 FR 82). We received no comments on the proposed rule. No public meeting was requested... River, National Harbor Access Channel, MD AGENCY: Coast Guard, DHS. ACTION: Temporary final...

  8. 78 FR 33219 - Special Local Regulations; Swim Across the Potomac, Potomac River; National Harbor Access Channel...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-04

    ... INFORMATION: Table of Acronyms DHS Department of Homeland Security FR Federal Register NPRM Notice of Proposed... Access Channel, MD'' in the Federal Register (78 FR 67). We received no comments on the proposed rule. No... rule, call or email Mr. Ronald Houck, U.S. Coast Guard Sector Baltimore, MD; telephone...

  9. Reconstitution of the Escherichia coli macrolide transporter: the periplasmic membrane fusion protein MacA stimulates the ATPase activity of MacB.

    PubMed

    Tikhonova, Elena B; Devroy, Vishakha K; Lau, Sze Yi; Zgurskaya, Helen I

    2007-02-01

    Periplasmic membrane fusion proteins (MFPs) are essential components of the type I protein secretion systems and drug efflux pumps in Gram-negative bacteria. Previous studies suggested that MFPs connect the inner and outer membrane components of the transport systems and by this means co-ordinate the transfer of substrates across the two membranes. In this study, we purified and reconstituted the macrolide transporter MacAB from Escherichia coli. Here, MacA is a periplasmic MFP and MacB is an ABC-type transporter. Similar to other MFP-dependent transporters from E. coli, the in vivo function of MacAB requires the outer membrane channel TolC. The purified MacB displayed a basal ATPase activity in detergent micelles. This activity conformed to Michaelis-Menten kinetics but was unresponsive to substrates or accessory proteins. Upon reconstitution into proteoliposomes, the ATPase activity of MacB was strictly dependent on MacA. The catalytic efficiency of MacAB ATPase was more than 45-fold higher than the activity of MacB alone. Both the N- and C-terminal regions of MacA were essential for this activity. MacA stimulated MacB ATPase only in phospholipid bilayers and did not need the presence of macrolides. Our results suggest that MacA is a functional subunit of the MacB transporter. PMID:17214741

  10. Q-ary collision resolution algorithms in random-access systems with free or blocked channel access

    NASA Astrophysics Data System (ADS)

    Mathys, P.; Flajolet, P.

    1985-03-01

    The throughput characteristics of contention-based random-access systems (RAS's) which use Q-ary tree algorithms (where Q equal to or greater than 2 is the number of groups into which contending users are split) of the Capetanakis-Tsybakov-Mikhailov-Vvedenskaya type are analyzed for an infinite population of identical users generating packets according to a Poisson process. Both free and blocked channel-access protocols are considered in combination with Q-ary collision resoluton algorithms that exploit either binary ('collision/no collision') or ternary ('collision/success/idle') feedback. For the resulting RAS's, functional equations for transformed generating functions of the first two moments of the collision resolution interval length are obtained and solved. The maximum stable throughput as a function of Q is given. The results of a packet-delay analysis are also given, and the analyzed RAS's are compared among themselves and with the slotted ALOHA system in terms of both system throughput and packet delay. It is concluded that the 'practical optimum' RAS (in terms of ease of implementation combined with good performance) uses free (i.e., immediate) channel access and ternary splitting (i.e., Q = 3) with binary feedback.

  11. Performance of Multiple Pulse Multiple Delay Modulated UWB Signals in a Multiple Access Indoor Wireless Channel

    SciTech Connect

    Nekoogar, F

    2003-06-12

    In this paper, the performance of a two user UWB multiple access (UWB-MA) system based on multiple-pulse multiple-delay (MPMD) modulation scheme in an indoor wireless channel is evaluated by computer simulations. The indoor multipath propagation channel model used in this study is based on the modified statistical Saleh-Valenzuela model proposed by Foerester and Li from Intel. The simulation results indicate that the multipath performance of MPMD modulated signals in a multiple access system outperforms the nonmultipath case as the number of autocorrelation function (ACF) sampling points increases for each user. This is an unusual but important result, since MPMD receiver exploits multipath phenomenon in indoor wireless channels to increase the BER performance, hence the transmission rate in a UWB-MA system.

  12. A membrane-access mechanism of ion channel inhibition by voltage sensor toxins from spider venom

    NASA Astrophysics Data System (ADS)

    Lee, Seok-Yong; MacKinnon, Roderick

    2004-07-01

    Venomous animals produce small protein toxins that inhibit ion channels with high affinity. In several well-studied cases the inhibitory proteins are water-soluble and bind at a channel's aqueous-exposed extracellular surface. Here we show that a voltage-sensor toxin (VSTX1) from the Chilean Rose Tarantula (Grammostola spatulata) reaches its target by partitioning into the lipid membrane. Lipid membrane partitioning serves two purposes: to localize the toxin in the membrane where the voltage sensor resides and to exploit the free energy of partitioning to achieve apparent high-affinity inhibition. VSTX1, small hydrophobic poisons and anaesthetic molecules reveal a common theme of voltage sensor inhibition through lipid membrane access. The apparent requirement for such access is consistent with the recent proposal that the sensor in voltage-dependent K+ channels is located at the membrane-protein interface.

  13. Accessibility of cysteines in the native bovine rod cGMP-gated channel.

    PubMed

    Bauer, Paul J; Krause, Eberhard

    2005-02-01

    Cyclic nucleotide-gated channels of photoreceptors and olfactory sensory neurons are tetramers consisting of A and B subunits. Here, the accessibility of the cysteines of the bovine rod cyclic nucleotide-gated channel is examined as a function of ligand binding. N-Ethylmaleimide-modified cysteines of both subunits were identified by mass spectrometry after trypsin digestion. In the absence of ligand, the intracellular carboxy-terminal cysteines of both subunits were accessible to N-ethylmaleimide. Activation of the channel abolished the accessibility of Cys505 of the A subunit and Cys1104 of the B subunit, with both being conserved cysteines of the cyclic nucleotide-binding sites. The cysteine of the pore loop of the B subunit was also found to be modified by this reagent in the absence of ligand. The total number of accessible cysteines of each subunit was determined by mass shifting upon modification with polyethylene glycol maleimide. In the absence of cyclic nucleotides, this hydrophilic reagent only weakly labeled cysteines of the A subunit but readily labeled at least three cysteines of the B subunit. Ligand binding exposed two cysteines of the A subunit and one cysteine of the B subunit to chemical modification. Double-modification experiments suggest that some of these cysteines are in or close to membrane-spanning domains. However, these cysteines could not yet be identified. Together, the cysteine accessibility of the native rod cyclic nucleotide-gated channel varies markedly upon ligand binding, thus indicating major structural rearrangements, which are of functional importance for channel activation. PMID:15683246

  14. Role of ATP binding and hydrolysis in assembly of MacAB-TolC macrolide transporter.

    PubMed

    Lu, Shuo; Zgurskaya, Helen I

    2012-12-01

    MacB is a founding member of the Macrolide Exporter family of transporters belonging to the ATP-Binding Cassette superfamily. These proteins are broadly represented in genomes of both Gram-positive and Gram-negative bacteria and are implicated in virulence and protection against antibiotics and peptide toxins. MacB transporter functions together with MacA, a periplasmic membrane fusion protein, which stimulates MacB ATPase. In Gram-negative bacteria, MacA is believed to couple ATP hydrolysis to transport of substrates across the outer membrane through a TolC-like channel. In this study, we report a real-time analysis of concurrent ATP hydrolysis and assembly of MacAB-TolC complex. MacB binds nucleotides with a low millimolar affinity and fast on- and off-rates. In contrast, MacA-MacB complex is formed with a nanomolar affinity, which further increases in the presence of ATP. Our results strongly suggest that association between MacA and MacB is stimulated by ATP binding to MacB but remains unchanged during ATP hydrolysis cycle. We also found that the large periplasmic loop of MacB plays the major role in coupling reactions separated in two different membranes. This loop is required for MacA-dependent stimulation of MacB ATPase and at the same time, contributes to recruitment of TolC into a trans-envelope complex. PMID:23057817

  15. Accessibility, reactivity, and selectivity of side chains within a channel of de novo peptide assembly.

    PubMed

    Burton, Antony J; Thomas, Franziska; Agnew, Christopher; Hudson, Kieran L; Halford, Stephen E; Brady, R Leo; Woolfson, Derek N

    2013-08-28

    Ab initio design of enzymes requires precise and predictable positioning of reactive functional groups within accessible and controlled environments of de novo protein scaffolds. Here we show that multiple thiol moieties can be placed within a central channel, with approximate dimensions 6 × 42 Å, of a de novo, six-helix peptide assembly (CC-Hex). Layers of six cysteine residues are introduced at two different sites ~6 (the "L24C" mutant) and ~17 Å (L17C) from the C-terminal opening of the channel. X-ray crystal structures confirm the mutant structures as hexamers with internal free thiol, rather than disulfide-linked cysteine residues. Both mutants are hexa-alkylated upon addition of iodoacetamide, demonstrating accessibility and full reactivity of the thiol groups. Comparison of the alkylation and unfolding rates of the hexamers indicates that access is directly through the channel and not via dissociation and unfolding of the assembly. Moreover, neither mutant reacts with iodoacetic acid, demonstrating selectivity of the largely hydrophobic channel. These studies show that it is possible to engineer reactive side chains with both precision and control into a de novo scaffold to produce protein-like structures with chemoselective reactivity. PMID:23924058

  16. Molecular dioxygen enters the active site of 12/15-lipoxygenase via dynamic oxygen access channels.

    PubMed

    Saam, Jan; Ivanov, Igor; Walther, Matthias; Holzhütter, Hermann-Georg; Kuhn, Hartmut

    2007-08-14

    Cells contain numerous enzymes that use molecular oxygen for their reactions. Often, their active sites are buried deeply inside the protein, which raises the question whether there are specific access channels guiding oxygen to the site of catalysis. Choosing 12/15-lipoxygenase as a typical example for such oxygen-dependent enzymes, we determined the oxygen distribution within the protein and defined potential routes for oxygen access. For this purpose, we have applied an integrated strategy of structural modeling, molecular dynamics simulations, site-directed mutagenesis, and kinetic measurements. First, we computed the 3D free-energy distribution for oxygen, which led to identification of four oxygen channels in the protein. All channels connect the protein surface with a region of high oxygen affinity at the active site. This region is localized opposite to the nonheme iron providing a structural explanation for the reaction specificity of this lipoxygenase isoform. The catalytically most relevant path can be obstructed by L367F exchange, which leads to a strongly increased Michaelis constant for oxygen. The blocking mechanism is explained in detail by reordering the hydrogen-bonding network of water molecules. Our results provide strong evidence that the main route for oxygen access to the active site of the enzyme follows a channel formed by transiently interconnected cavities whereby the opening and closure are governed by side chain dynamics. PMID:17675410

  17. Improved Iterative Decoding of Network-Channel Codes for Multiple-Access Relay Channel

    PubMed Central

    Majumder, Saikat; Verma, Shrish

    2015-01-01

    Cooperative communication using relay nodes is one of the most effective means of exploiting space diversity for low cost nodes in wireless network. In cooperative communication, users, besides communicating their own information, also relay the information of other users. In this paper we investigate a scheme where cooperation is achieved using a common relay node which performs network coding to provide space diversity for two information nodes transmitting to a base station. We propose a scheme which uses Reed-Solomon error correcting code for encoding the information bit at the user nodes and convolutional code as network code, instead of XOR based network coding. Based on this encoder, we propose iterative soft decoding of joint network-channel code by treating it as a concatenated Reed-Solomon convolutional code. Simulation results show significant improvement in performance compared to existing scheme based on compound codes. PMID:27347526

  18. Fairness of channel access for non-time-critical traffic using the FDDI token ring protocol

    NASA Technical Reports Server (NTRS)

    Johnson, M. J.

    1986-01-01

    The Fiber Distributed Data Interface (FDDI) is an ANSI draft proposed standard for a 100 megabit per second fiber optic token ring. FDDI supports two types of traffic, synchronous and asynchronous. Synchronous traffic is time critical traffic; stations are assigned guaranteed bandwidth to support their synchronous needs. Asynchronous traffic is lower priority and is sent only if time permits. It is proved analytically that the FDDI access protocol provides all stations on the ring with equal access to the channel to transmit asynchronous frames, regardless of the relative sizes of synchronous bandwidth allocations for individual stations. Analytic results are supported with data from simulation runs.

  19. A Survey of MAC Protocols for Cognitive Radio Body Area Networks.

    PubMed

    Bhandari, Sabin; Moh, Sangman

    2015-01-01

    The advancement in electronics, wireless communications and integrated circuits has enabled the development of small low-power sensors and actuators that can be placed on, in or around the human body. A wireless body area network (WBAN) can be effectively used to deliver the sensory data to a central server, where it can be monitored, stored and analyzed. For more than a decade, cognitive radio (CR) technology has been widely adopted in wireless networks, as it utilizes the available spectra of licensed, as well as unlicensed bands. A cognitive radio body area network (CRBAN) is a CR-enabled WBAN. Unlike other wireless networks, CRBANs have specific requirements, such as being able to automatically sense their environments and to utilize unused, licensed spectra without interfering with licensed users, but existing protocols cannot fulfill them. In particular, the medium access control (MAC) layer plays a key role in cognitive radio functions, such as channel sensing, resource allocation, spectrum mobility and spectrum sharing. To address various application-specific requirements in CRBANs, several MAC protocols have been proposed in the literature. In this paper, we survey MAC protocols for CRBANs. We then compare the different MAC protocols with one another and discuss challenging open issues in the relevant research. PMID:25903551

  20. A Survey of MAC Protocols for Cognitive Radio Body Area Networks

    PubMed Central

    Bhandari, Sabin; Moh, Sangman

    2015-01-01

    The advancement in electronics, wireless communications and integrated circuits has enabled the development of small low-power sensors and actuators that can be placed on, in or around the human body. A wireless body area network (WBAN) can be effectively used to deliver the sensory data to a central server, where it can be monitored, stored and analyzed. For more than a decade, cognitive radio (CR) technology has been widely adopted in wireless networks, as it utilizes the available spectra of licensed, as well as unlicensed bands. A cognitive radio body area network (CRBAN) is a CR-enabled WBAN. Unlike other wireless networks, CRBANs have specific requirements, such as being able to automatically sense their environments and to utilize unused, licensed spectra without interfering with licensed users, but existing protocols cannot fulfill them. In particular, the medium access control (MAC) layer plays a key role in cognitive radio functions, such as channel sensing, resource allocation, spectrum mobility and spectrum sharing. To address various application-specific requirements in CRBANs, several MAC protocols have been proposed in the literature. In this paper, we survey MAC protocols for CRBANs. We then compare the different MAC protocols with one another and discuss challenging open issues in the relevant research. PMID:25903551

  1. Fiverr MacGyver

    NASA Astrophysics Data System (ADS)

    Hut, Rolf; van de Giesen, Nick; Larson, Martha

    2014-05-01

    Crowdsourcing has become popular over the past years, also for scientific endeavors. There are many Citizen Science projects and crowdfunding platforms, such as Kickstarter, that are make helpful contributions to moving environmental science forward. An interesting underused source of useful crowd-derived contributions to research is the website Fiverr.com. On this platform, thousands of people, acting as small-scale freelance contractors, offer their skills in the form of services. The platform offers a chance for people to take a hobby, skill, or pastime and make it something more by reaching out to a wider audience and by receiving a payment in return for services. As is typical of other crowdsourcing platforms, the tasks are small and usually self contained. As the name Fiverr suggests, offers start at US5 to provide a particular service. Services offered range from graphic design, to messages sung or spoken with various styles or accents, to complete apps for Android or iPhone. Skill providers on the platform can accept a range of variation of definition in the tasks, some can be described in general terms, for others it is more appropriate to provide examples. Fiverr provides a central location for those offering skills and those needing services to find each other, it makes it possible to communicate and exchange files, to make payments, and it provides support for resolving disputes. In all cases, it is important to keep expectations aligned with the nature of the platform: quality can and will vary. Ultimately, the critical contribution of Fiverr is not to replace professional services or otherwise save money, but rather to provide access to a large group of people with specialized skills who are able to make a contribution on short notice. In the context of this session, it can be considered a pool of people with MacGyver skills lying in wait of a MacGyyer task to attack. There are many ways in which Fiverr tasks, which are called 'gigs', can be useful in

  2. Local anesthetic and antiepileptic drug access and binding to a bacterial voltage-gated sodium channel.

    PubMed

    Boiteux, Céline; Vorobyov, Igor; French, Robert J; French, Christopher; Yarov-Yarovoy, Vladimir; Allen, Toby W

    2014-09-01

    Voltage-gated sodium (Nav) channels are important targets in the treatment of a range of pathologies. Bacterial channels, for which crystal structures have been solved, exhibit modulation by local anesthetic and anti-epileptic agents, allowing molecular-level investigations into sodium channel-drug interactions. These structures reveal no basis for the "hinged lid"-based fast inactivation, seen in eukaryotic Nav channels. Thus, they enable examination of potential mechanisms of use- or state-dependent drug action based on activation gating, or slower pore-based inactivation processes. Multimicrosecond simulations of NavAb reveal high-affinity binding of benzocaine to F203 that is a surrogate for FS6, conserved in helix S6 of Domain IV of mammalian sodium channels, as well as low-affinity sites suggested to stabilize different states of the channel. Phenytoin exhibits a different binding distribution owing to preferential interactions at the membrane and water-protein interfaces. Two drug-access pathways into the pore are observed: via lateral fenestrations connecting to the membrane lipid phase, as well as via an aqueous pathway through the intracellular activation gate, despite being closed. These observations provide insight into drug modulation that will guide further developments of Nav inhibitors. PMID:25136136

  3. A study of MAC protocols for WBANs.

    PubMed

    Ullah, Sana; Shen, Bin; Islam, S M Riazul; Khan, Pervez; Saleem, Shahnaz; Kwak, Kyung Sup

    2010-01-01

    The seamless integration of low-power, miniaturised, invasive/non-invasive lightweight sensor nodes have contributed to the development of a proactive and unobtrusive Wireless Body Area Network (WBAN). A WBAN provides long-term health monitoring of a patient without any constraint on his/her normal dailylife activities. This monitoring requires the low-power operation of invasive/non-invasive sensor nodes. In other words, a power-efficient Medium Access Control (MAC) protocol is required to satisfy the stringent WBAN requirements, including low-power consumption. In this paper, we first outline the WBAN requirements that are important for the design of a low-power MAC protocol. Then we study low-power MAC protocols proposed/investigated for a WBAN with emphasis on their strengths and weaknesses. We also review different power-efficient mechanisms for a WBAN. In addition, useful suggestions are given to help the MAC designers to develop a low-power MAC protocol that will satisfy the stringent requirements. PMID:22315531

  4. MACS as a tool for international inspections

    SciTech Connect

    Curtiss, J.A.; Indusi, J.P.

    1995-06-01

    General acceptance of the challenge provision in the Chemical Weapons Convention has the potential for influence in other arms control areas. While most applications of the challenge inspection may be straightforward, there may be instances where access to the site by inspectors may be problematic. The MACS system described in this paper was developed to respond to these situations. Inspection and verification may be difficult when a host is unwilling,for valid reasons, to permit physical access to a site. We proposed a system of remote sensors which may be used to demonstrate compliance with Chemical Weapons Convention (CWC) challenge inspections even ff the inspector is physically excluded from a sensitive site. The system is based upon alternative-means-of-access provisions of the CWC. The Defense Nuclear Agency (DNA) funded design and construction of a system prototype, designated as MACS for Managed Access by Controlled Sensing. Features of the MACS design allow growth of the prototype into a versatile device for international monitoring of production facilities and other sites. MACS consists of instrumentation and communication equipment allowing site personnel to conduct a facility tour and perform acceptable measurements, while physically excluding the inspector from the facility. MACS consists of a base station used by the inspector, and a mobile unit used within the facility and manipulated by the facility staff. The base station and the mobile unit are @ed by a communication system, currently realized as a fiber optic cable. The mobile unit is equipped with television cameras and remote-reading distance-measuring equipment (DME) for use in verifying locations and dimensions. Global Positioning System receivers on the mobile unit provide both precise location and dead reckoning, suitable for tracking the mobile unit`s position while within a building when satellite signals are not available.

  5. Recent results from MAC

    SciTech Connect

    MAC Collaboration

    1982-05-01

    Some preliminary results from the MAC detector at PEP are presented. These include measurements of the angular distribution of ..gamma gamma.., ..mu mu.. and tau tau final states, a determination of the tau lifetime, a measurement of R, and a presentation of the inclusive muon p/sub perpendicular/ distribution for hadronic events.

  6. An integrated PHY-MAC analytical model for IEEE 802.15.7 VLC network with MPR capability

    NASA Astrophysics Data System (ADS)

    Yu, Hai-feng; Chi, Xue-fen; Liu, Jian

    2014-09-01

    Considering that the collision caused by hidden terminal is particularly serious due to the narrow beams of optical devices, the multi-packet reception (MPR) is introduced to mitigate the collisions for IEEE 802.15.7 visible light communication (VLC) system. To explore the impact of MPR on system performance and investigate the interaction between physical (PHY) layer and media access control (MAC) layer, a three dimensional (3D) integrated PHY-MAC analytical model of carrier sense multiple access/collision avoidance (CSMA/CA) is established based on Markov chain theory for VLC system, in which MPR is implemented through the use of orthogonal code sequence. Throughput is derived to evaluate the performance of VLC system with MPR capability under imperfect optical channel. The results can be used for the performance optimization of a VLC system with MPR capability.

  7. 47 CFR 69.709 - Dedicated transport and special access services other than channel terminations between LEC end...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... other than channel terminations between LEC end offices and customer premises. 69.709 Section 69.709... terminations between LEC end offices and customer premises. (a) Scope. This paragraph governs requests for... transport and special access services other than channel terminations between LEC end offices and...

  8. Results from MAC

    SciTech Connect

    Chadwick, G.B.

    1983-05-01

    The MAC detector has been exposed at PEP to 40 pb/sup -1/ luminosity of e/sup +/e/sup -/ collisions. The detector is described and recent results of a continuing analysis of hadronic cross section, lepton pair charge asymmetry, Bhabha process, two photon final state and radiative ..mu.. pairs are given. New results on flavor tagging of hadronic events with an inclusive ..mu.., and some searches for new particles are presented.

  9. The Users of Cable TV Access Channels: A Study of the Diffusion and Adoption of a Communications Innovation.

    ERIC Educational Resources Information Center

    Sparkes, Vernone M.

    A mail survey of 91 past and present users of the community programing (public access) channels in the Toronto, Canada, area revealed that personal contact is most important in the diffusion of knowledge about access opportunities. Friends and colleagues were the most often cited initial source of information; but contact by the cable company…

  10. A High Throughput Medium Access Control Implementation Based on IEEE 802.11e Standard

    NASA Astrophysics Data System (ADS)

    Huang, Min Li; Lee, Jin; Setiawan, Hendra; Ochi, Hiroshi; Park, Sin-Chong

    With the growing demand for high-performance multimedia applications over wireless channels, we need to develop a Medium Access Control (MAC) system that supports high throughput and quality of service enhancements. This paper presents the standard analysis, design architecture and design issues leading to the implementation of an IEEE 802.11e based MAC system that supports MAC throughput of over 100Mbps. In order to meet the MAC layer timing constraints, a hardware/software co-design approach is adopted. The proposed MAC architecture is implemented on the Xilinx Virtex-II Pro Field-Programmable Gate Array (FPGA) (XC2VP70-5FF1704C) prototype, and connected to a host computer through an external Universal Serial Bus (USB) interface. The total FPGA resource utilization is 11, 508 out of 33, 088 (34%) available slices. The measured MAC throughput is 100.7Mbps and 109.2Mbps for voice and video access categories, transmitted at a data rate of 260Mbps based on IEEE 802.11n Physical Layer (PHY), using the contention-based hybrid coordination function channel access mechanism.

  11. Cooperative Energy Harvesting-Adaptive MAC Protocol for WBANs

    PubMed Central

    Esteves, Volker; Antonopoulos, Angelos; Kartsakli, Elli; Puig-Vidal, Manel; Miribel-Català, Pere; Verikoukis, Christos

    2015-01-01

    In this paper, we introduce a cooperative medium access control (MAC) protocol, named cooperative energy harvesting (CEH)-MAC, that adapts its operation to the energy harvesting (EH) conditions in wireless body area networks (WBANs). In particular, the proposed protocol exploits the EH information in order to set an idle time that allows the relay nodes to charge their batteries and complete the cooperation phase successfully. Extensive simulations have shown that CEH-MAC significantly improves the network performance in terms of throughput, delay and energy efficiency compared to the cooperative operation of the baseline IEEE 802.15.6 standard. PMID:26029950

  12. Cooperative energy harvesting-adaptive MAC protocol for WBANs.

    PubMed

    Esteves, Volker; Antonopoulos, Angelos; Kartsakli, Elli; Puig-Vidal, Manel; Miribel-Català, Pere; Verikoukis, Christos

    2015-01-01

    In this paper, we introduce a cooperative medium access control (MAC) protocol, named cooperative energy harvesting (CEH)-MAC, that adapts its operation to the energy harvesting (EH) conditions in wireless body area networks (WBANs). In particular, the proposed protocol exploits the EH information in order to set an idle time that allows the relay nodes to charge their batteries and complete the cooperation phase successfully. Extensive simulations have shown that CEH-MAC significantly improves the network performance in terms of throughput, delay and energy efficiency compared to the cooperative operation of the baseline IEEE 802.15.6 standard. PMID:26029950

  13. An Enhanced Reservation-Based MAC Protocol for IEEE 802.15.4 Networks

    PubMed Central

    Afonso, José A.; Silva, Helder D.; Macedo, Pedro; Rocha, Luis A.

    2011-01-01

    The IEEE 802.15.4 Medium Access Control (MAC) protocol is an enabling standard for wireless sensor networks. In order to support applications requiring dedicated bandwidth or bounded delay, it provides a reservation-based scheme named Guaranteed Time Slot (GTS). However, the GTS scheme presents some drawbacks, such as inefficient bandwidth utilization and support to a maximum of only seven devices. This paper presents eLPRT (enhanced Low Power Real Time), a new reservation-based MAC protocol that introduces several performance enhancing features in comparison to the GTS scheme. This MAC protocol builds on top of LPRT (Low Power Real Time) and includes various mechanisms designed to increase data transmission reliability against channel errors, improve bandwidth utilization and increase the number of supported devices. A motion capture system based on inertial and magnetic sensors has been used to validate the protocol. The effectiveness of the performance enhancements introduced by each of the new features is demonstrated through the provision of both simulation and experimental results. PMID:22163826

  14. Scalable Lunar Surface Networks and Adaptive Orbit Access

    NASA Technical Reports Server (NTRS)

    Wang, Xudong

    2015-01-01

    Teranovi Technologies, Inc., has developed innovative network architecture, protocols, and algorithms for both lunar surface and orbit access networks. A key component of the overall architecture is a medium access control (MAC) protocol that includes a novel mechanism of overlaying time division multiple access (TDMA) and carrier sense multiple access with collision avoidance (CSMA/CA), ensuring scalable throughput and quality of service. The new MAC protocol is compatible with legacy Institute of Electrical and Electronics Engineers (IEEE) 802.11 networks. Advanced features include efficiency power management, adaptive channel width adjustment, and error control capability. A hybrid routing protocol combines the advantages of ad hoc on-demand distance vector (AODV) routing and disruption/delay-tolerant network (DTN) routing. Performance is significantly better than AODV or DTN and will be particularly effective for wireless networks with intermittent links, such as lunar and planetary surface networks and orbit access networks.

  15. Aeronautical Mobile Airport Communications System (AeroMACS)

    NASA Technical Reports Server (NTRS)

    Budinger, James M.; Hall, Edward

    2011-01-01

    To help increase the capacity and efficiency of the nation s airports, a secure wideband wireless communications system is proposed for use on the airport surface. This paper provides an overview of the research and development process for the Aeronautical Mobile Airport Communications System (AeroMACS). AeroMACS is based on a specific commercial profile of the Institute of Electrical and Electronics Engineers (IEEE) 802.16 standard known as Wireless Worldwide Interoperability for Microwave Access or WiMAX (WiMax Forum). The paper includes background on the need for global interoperability in air/ground data communications, describes potential AeroMACS applications, addresses allocated frequency spectrum constraints, summarizes the international standardization process, and provides findings and recommendations from the world s first AeroMACS prototype implemented in Cleveland, Ohio, USA.

  16. Bearer channel control protocol for the dynamic VB5.2 interface in ATM access networks

    NASA Astrophysics Data System (ADS)

    Fragoulopoulos, Stratos K.; Mavrommatis, K. I.; Venieris, Iakovos S.

    1996-12-01

    In the multi-vendor systems, a customer connected to an Access network (AN) must be capable of selecting a specific Service Node (SN) according to the services the SN provides. The multiplicity of technologically varying AN calls for the definition of a standard reference point between the AN and the SN widely known as the VB interface. Two versions are currently offered. The VB5.1 is simpler to implement but is not as flexible as the VB5.2, which supports switched connections. The VB5.2 functionality is closely coupled to the Broadband Bearer Channel Connection Protocol (B-BCCP). The B-BCCP is used for conveying the necessary information for dynamic resource allocation, traffic policing and routing in the AN as well as for information exchange concerning the status of the AN before a new call is established by the SN. By relying on such a protocol for the exchange of information instead of intercepting and interpreting signalling messages in the AN, the architecture of the AN is simplified because the functionality related to processing is not duplicated. In this paper a prominent B- BCCP candidate is defined, called the Service node Access network Interaction Protocol.

  17. Pliable Cognitive MAC for Heterogeneous Adaptive Cognitive Radio Sensor Networks.

    PubMed

    Al-Medhwahi, Mohammed; Hashim, Fazirulhisyam; Ali, Borhanuddin Mohd; Sali, Aduwati

    2016-01-01

    The rapid expansion of wireless monitoring and surveillance applications in several domains reinforces the trend of exploiting emerging technologies such as the cognitive radio. However, these technologies have to adjust their working concepts to consider the common characteristics of conventional wireless sensor networks (WSNs). The cognitive radio sensor network (CRSN), still an immature technology, has to deal with new networks that might have different types of data, traffic patterns, or quality of service (QoS) requirements. In this paper, we design and model a new cognitive radio-based medium access control (MAC) algorithm dealing with the heterogeneous nature of the developed networks in terms of either the traffic pattern or the required QoS for the node applications. The proposed algorithm decreases the consumed power on several fronts, provides satisfactory levels of latency and spectrum utilization with efficient scheduling, and manages the radio resources for various traffic conditions. An intensive performance evaluation is conducted to study the impact of key parameters such as the channel idle time length, node density, and the number of available channels. The performance evaluation of the proposed algorithm shows a better performance than the comparable protocols. Moreover, the results manifest that the proposed algorithm is suitable for real time monitoring applications. PMID:27257964

  18. Pliable Cognitive MAC for Heterogeneous Adaptive Cognitive Radio Sensor Networks

    PubMed Central

    Ali, Borhanuddin Mohd; Sali, Aduwati

    2016-01-01

    The rapid expansion of wireless monitoring and surveillance applications in several domains reinforces the trend of exploiting emerging technologies such as the cognitive radio. However, these technologies have to adjust their working concepts to consider the common characteristics of conventional wireless sensor networks (WSNs). The cognitive radio sensor network (CRSN), still an immature technology, has to deal with new networks that might have different types of data, traffic patterns, or quality of service (QoS) requirements. In this paper, we design and model a new cognitive radio-based medium access control (MAC) algorithm dealing with the heterogeneous nature of the developed networks in terms of either the traffic pattern or the required QoS for the node applications. The proposed algorithm decreases the consumed power on several fronts, provides satisfactory levels of latency and spectrum utilization with efficient scheduling, and manages the radio resources for various traffic conditions. An intensive performance evaluation is conducted to study the impact of key parameters such as the channel idle time length, node density, and the number of available channels. The performance evaluation of the proposed algorithm shows a better performance than the comparable protocols. Moreover, the results manifest that the proposed algorithm is suitable for real time monitoring applications. PMID:27257964

  19. Role of an isoform-specific substrate access channel residue in CO ligand accessibilities of neuronal and inducible nitric oxide synthase isoforms.

    PubMed

    Feng, Changjian; Fan, Weihong; Ghosh, Dipak K; Tollin, Gordon

    2011-03-01

    The rates of the bimolecular CO rebinding to the oxygenase domains of inducible and neuronal NOS proteins (iNOSoxy and nNOSoxy, respectively) after photolytic dissociation have been determined by laser flash photolysis. The following mutants at the isoform-specific sites (murine iNOSoxy N115L and rat nNOSoxy L337N, L337F) have been constructed to investigate role of the residues in the CO ligand accessibilities of the NOS isoforms. These residues are in the NOS distal substrate access channel. The effect of the (6R)-5,6,7,8-tetrahydrobiopterin (H(4)B) cofactor and l-arginine (Arg) substrate on the rates of CO rebinding have also been assessed. Addition of l-Arg to the iNOSoxy N115L mutant results in much faster CO rebinding rates, compared to the wild type. The results indicate that modifications to the iNOS channel in which the hydrophilic residue N115 is replaced by leucine (to resemble its nNOS cognate) open the channel somewhat, thereby improving access to the axial heme ligand binding position. On the other hand, introduction of a hydrophilic residue (L337N) or a bulky rigid aromatic residue (L337F) in the nNOS isoform does not significantly affect the kinetics profile, suggesting that the geometry of the substrate access pocket is not greatly altered. The bimolecular CO rebinding rate data indicate that the opening of the substrate access channel in the iNOS N115L mutant may be due to more widespread structural alterations induced by the mutation. PMID:21146639

  20. A Patterned Preamble MAC Protocol for Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Joe, Inwhee

    In this paper, we propose a novel MAC protocol with the patterned preamble technique to improve performance in terms of low power, channel utilization, and delay in wireless sensor networks. B-MAC is one of typical MAC protocols for wireless sensor networks using the duty cycle in order to achieve low-power operation. Since it works in an asynchronous fashion, B-MAC employs extended preamble and preamble sampling techniques. Even if it has outstanding performance in idle state, the overhead of these techniques is very large when packets are sent and received, because there is a lot of waste in the traditional preamble method. Instead of the simple preamble, our proposed MAC solution is to introduce more intelligent preamble with some patterns consisting of 2 phases (Tx phase & Ack phase). With this concept we implement real source code working on the mica2 platform with Tinyos-1.x version. Also, the test setup is presented, and the test results demonstrate that the proposed protocol provides better performance in terms of delay compared to B-MAC.

  1. Performance analysis of 2D asynchronous hard-limiting optical code-division multiple access system through atmospheric scattering channel

    NASA Astrophysics Data System (ADS)

    Zhao, Yaqin; Zhong, Xin; Wu, Di; Zhang, Ye; Ren, Guanghui; Wu, Zhilu

    2013-09-01

    Optical code-division multiple access (OCDMA) systems usually allocate orthogonal or quasi-orthogonal codes to the active users. When transmitting through atmospheric scattering channel, the coding pulses are broadened and the orthogonality of the codes is worsened. In truly asynchronous case, namely both the chips and the bits are asynchronous among each active user, the pulse broadening affects the system performance a lot. In this paper, we evaluate the performance of a 2D asynchronous hard-limiting wireless OCDMA system through atmospheric scattering channel. The probability density function of multiple access interference in truly asynchronous case is given. The bit error rate decreases as the ratio of the chip period to the root mean square delay spread increases and the channel limits the bit rate to different levels when the chip period varies.

  2. EISCAT observations during MAC/SINE and MAC/Epsilon

    NASA Technical Reports Server (NTRS)

    Roettger, J.; Hoppe, U.-P.; Hall, C.

    1989-01-01

    The EISCAT incoherent scatter radar facility in Tromsoe, Norway was operated during the MAC/SINE campaign for 78 hours in the period 10 June to 17 July 1987, and during the MAC/Epsilon campaign for 90 hours in the period 15 October to 5 November 1987. The VHF (224 MHz) radar operations during MAC/SINE yielded most interesting observations of strong coherent echoes from the mesopause region. Characteristic data of these polar mesospheric summer echoes are presented. The UHF (933 MHz) radar operations during MAC/Epsilon were done with 18 deg off zenith beam and allows the deduction of meridonal and horizontal wind components as well as radial velocity spectra in addition to the usual electron density profiles in the D and lower E regions. Some results from the VHF and UHF radars indicating the presence of gravity waves are examined.

  3. Accessibility

    MedlinePlus

    ... www.nlm.nih.gov/medlineplus/accessibility.html MedlinePlus Accessibility To use the sharing features on this page, ... Subscribe to RSS Follow us Disclaimers Copyright Privacy Accessibility Quality Guidelines Viewers & Players MedlinePlus Connect for EHRs ...

  4. MacB ABC transporter is a dimer whose ATPase activity and macrolide-binding capacity are regulated by the membrane fusion protein MacA.

    PubMed

    Lin, Hong Ting; Bavro, Vassiliy N; Barrera, Nelson P; Frankish, Helen M; Velamakanni, Saroj; van Veen, Hendrik W; Robinson, Carol V; Borges-Walmsley, M Inês; Walmsley, Adrian R

    2009-01-01

    Gram-negative bacteria utilize specialized machinery to translocate drugs and protein toxins across the inner and outer membranes, consisting of a tripartite complex composed of an inner membrane secondary or primary active transporter (IMP), a periplasmic membrane fusion protein, and an outer membrane channel. We have investigated the assembly and function of the MacAB/TolC system that confers resistance to macrolides in Escherichia coli. The membrane fusion protein MacA not only stabilizes the tripartite assembly by interacting with both the inner membrane protein MacB and the outer membrane protein TolC, but also has a role in regulating the function of MacB, apparently increasing its affinity for both erythromycin and ATP. Analysis of the kinetic behavior of ATP hydrolysis indicated that MacA promotes and stabilizes the ATP-binding form of the MacB transporter. For the first time, we have established unambiguously the dimeric nature of a noncanonic ABC transporter, MacB that has an N-terminal nucleotide binding domain, by means of nondissociating mass spectrometry, analytical ultracentrifugation, and atomic force microscopy. Structural studies of ABC transporters indicate that ATP is bound between a pair of nucleotide binding domains to stabilize a conformation in which the substrate-binding site is outward-facing. Consequently, our data suggest that in the presence of ATP the same conformation of MacB is promoted and stabilized by MacA. Thus, MacA would facilitate the delivery of drugs by MacB to TolC by enhancing the binding of drugs to it and inducing a conformation of MacB that is primed and competent for binding TolC. Our structural studies are an important first step in understanding how the tripartite complex is assembled. PMID:18955484

  5. MacB ABC Transporter Is a Dimer Whose ATPase Activity and Macrolide-binding Capacity Are Regulated by the Membrane Fusion Protein MacA*S⃞

    PubMed Central

    Lin, Hong Ting; Bavro, Vassiliy N.; Barrera, Nelson P.; Frankish, Helen M.; Velamakanni, Saroj; van Veen, Hendrik W.; Robinson, Carol V.; Borges-Walmsley, M. Inês; Walmsley, Adrian R.

    2009-01-01

    Gram-negative bacteria utilize specialized machinery to translocate drugs and protein toxins across the inner and outer membranes, consisting of a tripartite complex composed of an inner membrane secondary or primary active transporter (IMP), a periplasmic membrane fusion protein, and an outer membrane channel. We have investigated the assembly and function of the MacAB/TolC system that confers resistance to macrolides in Escherichia coli. The membrane fusion protein MacA not only stabilizes the tripartite assembly by interacting with both the inner membrane protein MacB and the outer membrane protein TolC, but also has a role in regulating the function of MacB, apparently increasing its affinity for both erythromycin and ATP. Analysis of the kinetic behavior of ATP hydrolysis indicated that MacA promotes and stabilizes the ATP-binding form of the MacB transporter. For the first time, we have established unambiguously the dimeric nature of a noncanonic ABC transporter, MacB that has an N-terminal nucleotide binding domain, by means of nondissociating mass spectrometry, analytical ultracentrifugation, and atomic force microscopy. Structural studies of ABC transporters indicate that ATP is bound between a pair of nucleotide binding domains to stabilize a conformation in which the substrate-binding site is outward-facing. Consequently, our data suggest that in the presence of ATP the same conformation of MacB is promoted and stabilized by MacA. Thus, MacA would facilitate the delivery of drugs by MacB to TolC by enhancing the binding of drugs to it and inducing a conformation of MacB that is primed and competent for binding TolC. Our structural studies are an important first step in understanding how the tripartite complex is assembled. PMID:18955484

  6. MAC mini acceptance test procedures, software Version 3.3

    SciTech Connect

    Russell, V.K.

    1994-10-17

    The K Basins Materials Accounting (MAC) programs had some improvements made to it to to change slightly the access authorized users had to the modification of critical data. This ATP describes how the code was to be tested to verify its correctness.

  7. The ability to create NTD silicon technology in the IRT-T reactor in a horizontal experimental channel with one-side access

    NASA Astrophysics Data System (ADS)

    Varlachev, V. A.; Golovatsky, A. V.; Emets, E. G.; Butko, Ya A.

    2016-06-01

    The article shows the ability of creation of neutron transmutation doping (NTD) of monocrystalline silicon technology in the reactor's channel, which has a one-side access. In the article a distribution of thermal neutron flux through the length of channel and it's radius, neutron spectrum were obtained which confirmed that horizontal experimental channel HEC-1 is suitable for NTD.

  8. Clinical Outcomes After Cervical Transcorporeal Microdecompression and Vertebral Body Access Channel Repair

    PubMed Central

    Lowry, David W.; Tuinstra, Scott M.; Liang, Kevin

    2015-01-01

    Background Although anterior cervical decompression and fusion (ACDF) can be performed using minimally invasive techniques, the extensive removal of anatomical keystones during decompression requires a segmental fusion to restore biomechanical stability. Treatment with arthrodesis techniques may result in a prolonged recovery time, loss of motion, and the need for further treatment if a pseudarthosis or adjacent segment disease occur. Transcorporeal micro decompression (TCMD) is a newly developed motion sparing, minimally invasive anterior cervical spine decompression procedure that utilizes a small channel through the cervical vertebral body to decompress areas of central or foraminal stenosis while preserving the native disc. Cervical decompression with TCMD can be performed as a stand-alone or hybrid procedure with ACDF at the adjacent levels. This study retrospectively assesses patient based clinical outcome measures in patients treated with TCMD. Methods A retrospective, non-randomized, single-center chart review of single surgeon experience with patients undergoing TCMD both with and without adjacent level ACDF using both a trajectory control guide and access channel repair. Statistical analyses were performed on pre and post-operative data collected using visual analog scale (VAS) and neck disability index (NDI) outcome measures. Results Among 62 patients, there were no cases of neurovascular injury, CSF leak, transfusion, or migration of repair implement. Revision surgery was required in 6.4% (n=4) patients. A subanalysis of outcome metrics was performed for patients that underwent standalone TCMD (TCMD group, n=42) and TCMD with concurrent ACDF at one or more levels (TCMD+ACDF group, n=20). TCMD group NDI improved from 20.0 to 2.7 at 1 year (p=0.0001); Axial VAS improved from 5.5 to 0.6 (p=0.0001); and Radiating VAS improved from 7.0 to 0.7 (p=0.0001). TCMD+ACDF group NDI improved from 22.0 to 4.0 at 1 year (p=0.004); Axial VAS improved from 7.1 to 1.2 (p

  9. Cysteine accessibility probes timing and extent of NBD separation along the dimer interface in gating CFTR channels

    PubMed Central

    Chaves, Luiz A. Poletto

    2015-01-01

    Cystic fibrosis transmembrane conductance regulator (CFTR) channel opening and closing are driven by cycles of adenosine triphosphate (ATP) binding–induced formation and hydrolysis-triggered disruption of a heterodimer of its cytoplasmic nucleotide-binding domains (NBDs). Although both composite sites enclosed within the heterodimer interface contain ATP in an open CFTR channel, ATP hydrolysis in the sole catalytically competent site causes channel closure. Opening of the NBD interface at that site then allows ADP–ATP exchange. But how frequently, and how far, the NBD surfaces separate at the other, inactive composite site remains unclear. We assessed separation at each composite site by monitoring access of nucleotide-sized hydrophilic, thiol-specific methanothiosulfonate (MTS) reagents to interfacial target cysteines introduced into either LSGGQ-like ATP-binding cassette signature sequence (replacing equivalent conserved serines: S549 and S1347). Covalent MTS-dependent modification of either cysteine while channels were kept closed by the absence of ATP impaired subsequent opening upon ATP readdition. Modification while channels were opening and closing in the presence of ATP caused macroscopic CFTR current to decline at the same speed as when the unmodified channels shut upon sudden ATP withdrawal. These results suggest that the target cysteines can be modified only in closed channels; that after modification the attached MTS adduct interferes with ATP-mediated opening; and that modification in the presence of ATP occurs rapidly once channels close, before they can reopen. This interpretation was corroborated by the finding that, for either cysteine target, the addition of the hydrolysis-impairing mutation K1250R (catalytic site Walker A Lys) similarly slowed, by an order of magnitude, channel closing on ATP removal and the speed of modification by MTS reagent in ATP. We conclude that, in every CFTR channel gating cycle, the NBD dimer interface separates

  10. A Cloud-Assisted Random Linear Network Coding Medium Access Control Protocol for Healthcare Applications

    PubMed Central

    Kartsakli, Elli; Antonopoulos, Angelos; Alonso, Luis; Verikoukis, Christos

    2014-01-01

    Relay sensor networks are often employed in end-to-end healthcare applications to facilitate the information flow between patient worn sensors and the medical data center. Medium access control (MAC) protocols, based on random linear network coding (RLNC), are a novel and suitable approach to efficiently handle data dissemination. However, several challenges arise, such as additional delays introduced by the intermediate relay nodes and decoding failures, due to channel errors. In this paper, we tackle these issues by adopting a cloud architecture where the set of relays is connected to a coordinating entity, called cloud manager. We propose a cloud-assisted RLNC-based MAC protocol (CLNC-MAC) and develop a mathematical model for the calculation of the key performance metrics, namely the system throughput, the mean completion time for data delivery and the energy efficiency. We show the importance of central coordination in fully exploiting the gain of RLNC under error-prone channels. PMID:24618727

  11. Nonadditivity of quantum and classical capacities for entanglement breaking multiple-access channels and the butterfly network

    SciTech Connect

    Grudka, Andrzej; Horodecki, Pawel

    2010-06-15

    We analyze quantum network primitives which are entanglement breaking. We show superadditivity of quantum and classical capacity regions for quantum multiple-access channels and the quantum butterfly network. Since the effects are especially visible at high noise they suggest that quantum information effects may be particularly helpful in the case of the networks with occasional high noise rates. The present effects provide a qualitative borderline between superadditivities of bipartite and multipartite systems.

  12. The Channel Acquisition Slot Protocol

    NASA Astrophysics Data System (ADS)

    Milian, Arturo Valencia; Tamura, Shinsuke; Yanase, Tatsuro

    This paper discusses the Channel Acquisition Slot Protocol (CASP), a new protocol for the Media Access Control (MAC) of wireless networks. The CASP is intended to provide a more efficient use of communication channels; this is achieved by mechanisms for eliminating contentions among network stations and by an implicit handling of acknowledge messages. To avoid collisions of messages, the protocol divides the time into short slots, each of which is assigned to a single station, and any station must wait its own slot to start its transmission. However once a transmission is started the slot can be extended and no other station can make use of the channel. The use of an implicit acknowledge mechanism removes the necessity of an acknowledge message exchange for every transmission. In various simulated scenarios the CASP shows a 25% better throughput efficiency compared with the one of the IEEE802.11 protocol.

  13. 18 CFR 1304.207 - Channel excavation on TVA-owned residential access shoreland.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... reservoir drawdown periods. (g) Channel excavations must be accomplished during the reservoir drawdown when the reservoir bottom is exposed and dry. (h) Spoil material from channel excavations must be placed in... Risk Profile elevation. For those reservoirs that have no flood control storage, dredge spoil must...

  14. 18 CFR 1304.207 - Channel excavation on TVA-owned residential access shoreland.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... reservoir drawdown periods. (g) Channel excavations must be accomplished during the reservoir drawdown when the reservoir bottom is exposed and dry. (h) Spoil material from channel excavations must be placed in... Risk Profile elevation. For those reservoirs that have no flood control storage, dredge spoil must...

  15. 18 CFR 1304.207 - Channel excavation on TVA-owned residential access shoreland.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... reservoir drawdown periods. (g) Channel excavations must be accomplished during the reservoir drawdown when the reservoir bottom is exposed and dry. (h) Spoil material from channel excavations must be placed in... Risk Profile elevation. For those reservoirs that have no flood control storage, dredge spoil must...

  16. Congruent pattern of accessibility identifies minimal pore gate in a non-symmetric voltage-gated sodium channel

    PubMed Central

    Oelstrom, Kevin; Chanda, Baron

    2016-01-01

    Opening and closing of the central ion-conducting pore in voltage-dependent ion channels is gated by changes in membrane potential. Although a gate residue in the eukaryotic voltage-gated sodium channel has been identified, the minimal molecular determinants of this gate region remain unknown. Here, by measuring the closed- and open-state reactivity of MTSET to substituted cysteines in all the pore-lining helices, we show that the state-dependent accessibility is delineated by four hydrophobic residues at homologous positions in each domain. Introduced cysteines above these sites do not react with intracellular MTSET while the channels are closed and yet are rapidly modified while the channels are open. These findings, in conjunction with state-dependent metal cross-bridging, support the notion that the gate residues in each of the four S6 segments of the eukaryotic sodium channel form an occlusion for ions in the closed state and are splayed open on activation. PMID:27186888

  17. Congruent pattern of accessibility identifies minimal pore gate in a non-symmetric voltage-gated sodium channel.

    PubMed

    Oelstrom, Kevin; Chanda, Baron

    2016-01-01

    Opening and closing of the central ion-conducting pore in voltage-dependent ion channels is gated by changes in membrane potential. Although a gate residue in the eukaryotic voltage-gated sodium channel has been identified, the minimal molecular determinants of this gate region remain unknown. Here, by measuring the closed- and open-state reactivity of MTSET to substituted cysteines in all the pore-lining helices, we show that the state-dependent accessibility is delineated by four hydrophobic residues at homologous positions in each domain. Introduced cysteines above these sites do not react with intracellular MTSET while the channels are closed and yet are rapidly modified while the channels are open. These findings, in conjunction with state-dependent metal cross-bridging, support the notion that the gate residues in each of the four S6 segments of the eukaryotic sodium channel form an occlusion for ions in the closed state and are splayed open on activation. PMID:27186888

  18. Interference Analysis Status and Plans for Aeronautical Mobile Airport Communications System (AeroMACS)

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.; Wilson, Jeffrey D.

    2010-01-01

    Interference issues related to the operation of an aeronautical mobile airport communications system (AeroMACS) in the C-Band (specifically 5091-5150 MHz) is being investigated. The issue of primary interest is co-channel interference from AeroMACS into mobile-satellite system (MSS) feeder uplinks. The effort is focusing on establishing practical limits on AeroMACS transmissions from airports so that the threshold of interference into MSS is not exceeded. The analyses are being performed with the software package Visualyse Professional, developed by Transfinite Systems Limited. Results with omni-directional antennas and plans to extend the models to represent AeroMACS more accurately will be presented. These models should enable realistic analyses of emerging AeroMACS designs to be developed from NASA Test Bed, RTCA 223, and European results.

  19. The Multidimensional Audioconferencing Classification System (MACS).

    ERIC Educational Resources Information Center

    Cookson, Peter S.; Chang, Yu-bi

    1995-01-01

    Describes the development of the Multidimensional Audioconferencing Classification System (MACS), an instrument for the tabulation, analysis, and interpretation of audioconferencing instructional interactions. MACS draws on three theoretical and empirical streams: (1) systematic small group interaction analysis; (2) systematic classroom…

  20. An Energy-Efficient, Application-Oriented Control Algorithm for MAC Protocols in WSN

    NASA Astrophysics Data System (ADS)

    Li, Deliang; Peng, Fei; Qian, Depei

    Energy efficiency has been a main concern in wireless sensor networks where Medium Access Control (MAC) protocol plays an important role. However, current MAC protocols designed for energy saving have seldom considered multiple applications coexisting in WSN with variation of traffic load dynamics and different QoS requirements. In this paper, we propose an adaptive control algorithm at MAC layer to promote energy efficiency. We focus on the tradeoff relation between collisions and control overhead as a reflection of traffic load and propose to balance the tradeoff under the constraints of QoS options. We integrate the algorithm into S-MAC and verify it through NS-2 platform. The results demonstrate the algorithm achieves observable improvement in energy performance while meeting QoS requirement for different coexisting applications in comparison with S-MAC.

  1. Access channel residues Ser315 and Asp137 in Mycobacterium tuberculosis catalase-peroxidase (KatG) control peroxidatic activation of the pro-drug isoniazid

    PubMed Central

    Zhao, Xiangbo; Hersleth, Hans-Petter; Zhu, Janan; Andersson, K. Kristoffer; Magliozzo, Richard S.

    2013-01-01

    Peroxidatic activation of the anti-tuberculosis pro-drug isoniazid by Mycobacterium tuberculosis catalase-peroxidase (KatG) is regulated by gating residues of a heme access channel. The steric restriction at the bottleneck of this channel is alleviated by replacement of residue Asp137 with Ser, according to crystallographic and kinetic studies. PMID:24185282

  2. Real-time demonstration of QoS guaranteed 25-Gb/s PON prototype with Ethernet-PON MAC/PHY and cost-effective APD receivers for 100-Gb/s access networks.

    PubMed

    Lee, Han Hyub; Doo, Kyeong-Hwan; Mun, Sil-Gu; Kim, Kwangok; Lee, Jie Hyun; Kang, Sae-Kyoung; Park, Heuk; Park, Nowook; Park, Hyungjin; Chung, Hwan Seok

    2016-06-27

    We demonstrate a real-time 25-Gb/s PON prototype with ethernet-PON MAC/PHY, O-band transmitter, and cost-effective APD receivers. With applying parasitic inductance and capacitance reduction, the frequency response of 25-Gb/s APD ROSA with TO46-pacakge is improved to support high receiver sensitivity around -25 dBm at the BER of 10-3. The 30 dB power budget of 25 Gb/s downstream is achieved at the BER of 10-3. With long-term ethernet packet transmission, 25 Gigabit and 10 Gigabit ethernet traffics are successfully transmitted through the 20-km SMF over 14 hour's observation window. Furthermore, QoS and bandwidth re-assignment function of the 25-Gb/s PON prototype are successfully demonstrated with respect to residential, business and mobile backhaul services in ONUs. PMID:27410561

  3. Functionally Active T1-T1 Interfaces Revealed by the Accessibility of Intracellular Thiolate Groups in Kv4 Channels

    PubMed Central

    Wang, Guangyu; Shahidullah, Mohammad; Rocha, Carmen A.; Strang, Candace; Pfaffinger, Paul J.; Covarrubias, Manuel

    2005-01-01

    Gating of voltage-dependent K+ channels involves movements of membrane-spanning regions that control the opening of the pore. Much less is known, however, about the contributions of large intracellular channel domains to the conformational changes that underlie gating. Here, we investigated the functional role of intracellular regions in Kv4 channels by probing relevant cysteines with thiol-specific reagents. We find that reagent application to the intracellular side of inside-out patches results in time-dependent irreversible inhibition of Kv4.1 and Kv4.3 currents. In the absence or presence of Kv4-specific auxiliary subunits, mutational and electrophysiological analyses showed that none of the 14 intracellular cysteines is essential for channel gating. C110, C131, and C132 in the intersubunit interface of the tetramerization domain (T1) are targets responsible for the irreversible inhibition by a methanethiosulfonate derivative (MTSET). This result is surprising because structural studies of Kv4-T1 crystals predicted protection of the targeted thiolate groups by constitutive high-affinity Zn2+ coordination. Also, added Zn2+ or a potent Zn2+ chelator (TPEN) does not significantly modulate the accessibility of MTSET to C110, C131, or C132; and furthermore, when the three critical cysteines remained as possible targets, the MTSET modification rate of the activated state is ∼200-fold faster than that of the resting state. Biochemical experiments confirmed the chemical modification of the intact α-subunit and the purified tetrameric T1 domain by MTS reagents. These results conclusively demonstrate that the T1–T1 interface of Kv4 channels is functionally active and dynamic, and that critical reactive thiolate groups in this interface may not be protected by Zn2+ binding. PMID:15955876

  4. Channel access schemes and fiber optic configurations for integrated-services local area networks. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Nassehi, M. Mehdi

    1987-01-01

    Local Area Networks are in common use for data communications and have enjoyed great success. Recently, there is a growing interest in using a single network to support many applications in addition to traditional data traffic. These additional applications introduce new requirements in terms of volume of traffic and real-time delivery of data which are not met by existing networks. To satisfy these requirements, a high-bandwidth tranmission medium, such as fiber optics, and a distributed channel access scheme for the efficient sharing of the bandwidth among the various applications are needed. As far as the throughput-delay requirements of the various application are concerned, a network structure along with a distributed channel access are proposed which incorporate appropriate scheduling policies for the transmission of outstanding messages on the network. A dynamic scheduling policy was devised which outperforms all existing policies in terms of minimizing the expected cost per message. A broadcast mechanism was devised for the efficient dissemination of all relevant information. Fiber optic technology is considered for the high-bandwidth transmisison medium.

  5. Medical-Grade Channel Access and Admission Control in 802.11e EDCA for Healthcare Applications

    PubMed Central

    Son, Sunghwa; Park, Kyung-Joon; Park, Eun-Chan

    2016-01-01

    In this paper, we deal with the problem of assuring medical-grade quality of service (QoS) for real-time medical applications in wireless healthcare systems based on IEEE 802.11e. Firstly, we show that the differentiated channel access of IEEE 802.11e cannot effectively assure medical-grade QoS because of priority inversion. To resolve this problem, we propose an efficient channel access algorithm. The proposed algorithm adjusts arbitrary inter-frame space (AIFS) in the IEEE 802.11e protocol depending on the QoS measurement of medical traffic, to provide differentiated near-absolute priority for medical traffic. In addition, based on rigorous capacity analysis, we propose an admission control scheme that can avoid performance degradation due to network overload. Via extensive simulations, we show that the proposed mechanism strictly assures the medical-grade QoS and improves the throughput of low-priority traffic by more than several times compared to the conventional IEEE 802.11e. PMID:27490666

  6. Coenzyme Q Biosynthesis: Evidence for a Substrate Access Channel in the FAD-Dependent Monooxygenase Coq6

    PubMed Central

    Ismail, Alexandre; Leroux, Vincent; Smadja, Myriam; Gonzalez, Lucie; Lombard, Murielle; Pierrel, Fabien; Mellot-Draznieks, Caroline; Fontecave, Marc

    2016-01-01

    Coq6 is an enzyme involved in the biosynthesis of coenzyme Q, a polyisoprenylated benzoquinone lipid essential to the function of the mitochondrial respiratory chain. In the yeast Saccharomyces cerevisiae, this putative flavin-dependent monooxygenase is proposed to hydroxylate the benzene ring of coenzyme Q (ubiquinone) precursor at position C5. We show here through biochemical studies that Coq6 is a flavoprotein using FAD as a cofactor. Homology models of the Coq6-FAD complex are constructed and studied through molecular dynamics and substrate docking calculations of 3-hexaprenyl-4-hydroxyphenol (4-HP6), a bulky hydrophobic model substrate. We identify a putative access channel for Coq6 in a wild type model and propose in silico mutations positioned at its entrance capable of partially (G248R and L382E single mutations) or completely (a G248R-L382E double-mutation) blocking access to the channel for the substrate. Further in vivo assays support the computational predictions, thus explaining the decreased activities or inactivation of the mutated enzymes. This work provides the first detailed structural information of an important and highly conserved enzyme of ubiquinone biosynthesis. PMID:26808124

  7. Medical-Grade Channel Access and Admission Control in 802.11e EDCA for Healthcare Applications.

    PubMed

    Son, Sunghwa; Park, Kyung-Joon; Park, Eun-Chan

    2016-01-01

    In this paper, we deal with the problem of assuring medical-grade quality of service (QoS) for real-time medical applications in wireless healthcare systems based on IEEE 802.11e. Firstly, we show that the differentiated channel access of IEEE 802.11e cannot effectively assure medical-grade QoS because of priority inversion. To resolve this problem, we propose an efficient channel access algorithm. The proposed algorithm adjusts arbitrary inter-frame space (AIFS) in the IEEE 802.11e protocol depending on the QoS measurement of medical traffic, to provide differentiated near-absolute priority for medical traffic. In addition, based on rigorous capacity analysis, we propose an admission control scheme that can avoid performance degradation due to network overload. Via extensive simulations, we show that the proposed mechanism strictly assures the medical-grade QoS and improves the throughput of low-priority traffic by more than several times compared to the conventional IEEE 802.11e. PMID:27490666

  8. OTRA-THS MAC to reduce Power Outage Data Collection Latency in a smart meter network

    SciTech Connect

    Garlapati, Shravan K; Kuruganti, Phani Teja; Buehrer, Richard M; Reed, Jeffrey H

    2014-01-01

    The deployment of advanced metering infrastructure by the electric utilities poses unique communication challenges, particularly as the number of meters per aggregator increases. During a power outage, a smart meter tries to report it instantaneously to the electric utility. In a densely populated residential/industrial locality, it is possible that a large number of smart meters simultaneously try to get access to the communication network to report the power outage. If the number of smart meters is very high of the order of tens of thousands (metropolitan areas), the power outage data flooding can lead to Random Access CHannel (RACH) congestion. Several utilities are considering the use of cellular network for smart meter communications. In 3G/4G cellular networks, RACH congestion not only leads to collisions, retransmissions and increased RACH delays, but also has the potential to disrupt the dedicated traffic flow by increasing the interference levels (3G CDMA). In order to overcome this problem, in this paper we propose a Time Hierarchical Scheme (THS) that reduces the intensity of power outage data flooding and power outage reporting delay by 6/7th, and 17/18th when compared to their respective values without THS. Also, we propose an Optimum Transmission Rate Adaptive (OTRA) MAC to optimize the latency in power outage data collection. The analysis and simulation results presented in this paper show that both the OTRA and THS features of the proposed MAC results in a Power Outage Data Collection Latency (PODCL) that is 1/10th of the 4G LTE PODCL.

  9. Channel

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03693 Channel

    This channel is located south of Iani Chaos.

    Image information: VIS instrument. Latitude -10.9N, Longitude 345.5E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  10. Different pH-sensitivity patterns of 30 sodium channel inhibitors suggest chemically different pools along the access pathway.

    PubMed

    Lazar, Alexandra; Lenkey, Nora; Pesti, Krisztina; Fodor, Laszlo; Mike, Arpad

    2015-01-01

    The major drug binding site of sodium channels is inaccessible from the extracellular side, drug molecules can only access it either from the membrane phase, or from the intracellular aqueous phase. For this reason, ligand-membrane interactions are as important determinants of inhibitor properties, as ligand-protein interactions. One-way to probe this is to modify the pH of the extracellular fluid, which alters the ratio of charged vs. uncharged forms of some compounds, thereby changing their interaction with the membrane. In this electrophysiology study we used three different pH values: 6.0, 7.3, and 8.6 to test the significance of the protonation-deprotonation equilibrium in drug access and affinity. We investigated drugs of several different indications: carbamazepine, lamotrigine, phenytoin, lidocaine, bupivacaine, mexiletine, flecainide, ranolazine, riluzole, memantine, ritanserin, tolperisone, silperisone, ambroxol, haloperidol, chlorpromazine, clozapine, fluoxetine, sertraline, paroxetine, amitriptyline, imipramine, desipramine, maprotiline, nisoxetine, mianserin, mirtazapine, venlafaxine, nefazodone, and trazodone. We recorded the pH-dependence of potency, reversibility, as well as onset/offset kinetics. As expected, we observed a strong correlation between the acidic dissociation constant (pKa) of drugs and the pH-dependence of their potency. Unexpectedly, however, the pH-dependence of reversibility or kinetics showed diverse patterns, not simple correlation. Our data are best explained by a model where drug molecules can be trapped in at least two chemically different environments: A hydrophilic trap (which may be the aqueous cavity within the inner vestibule), which favors polar and less lipophilic compounds, and a lipophilic trap (which may be the membrane phase itself, and/or lipophilic binding sites on the channel). Rescue from the hydrophilic and lipophilic traps can be promoted by alkalic and acidic extracellular pH, respectively. PMID:26441665

  11. Different pH-sensitivity patterns of 30 sodium channel inhibitors suggest chemically different pools along the access pathway

    PubMed Central

    Lazar, Alexandra; Lenkey, Nora; Pesti, Krisztina; Fodor, Laszlo; Mike, Arpad

    2015-01-01

    The major drug binding site of sodium channels is inaccessible from the extracellular side, drug molecules can only access it either from the membrane phase, or from the intracellular aqueous phase. For this reason, ligand-membrane interactions are as important determinants of inhibitor properties, as ligand-protein interactions. One-way to probe this is to modify the pH of the extracellular fluid, which alters the ratio of charged vs. uncharged forms of some compounds, thereby changing their interaction with the membrane. In this electrophysiology study we used three different pH values: 6.0, 7.3, and 8.6 to test the significance of the protonation-deprotonation equilibrium in drug access and affinity. We investigated drugs of several different indications: carbamazepine, lamotrigine, phenytoin, lidocaine, bupivacaine, mexiletine, flecainide, ranolazine, riluzole, memantine, ritanserin, tolperisone, silperisone, ambroxol, haloperidol, chlorpromazine, clozapine, fluoxetine, sertraline, paroxetine, amitriptyline, imipramine, desipramine, maprotiline, nisoxetine, mianserin, mirtazapine, venlafaxine, nefazodone, and trazodone. We recorded the pH-dependence of potency, reversibility, as well as onset/offset kinetics. As expected, we observed a strong correlation between the acidic dissociation constant (pKa) of drugs and the pH-dependence of their potency. Unexpectedly, however, the pH-dependence of reversibility or kinetics showed diverse patterns, not simple correlation. Our data are best explained by a model where drug molecules can be trapped in at least two chemically different environments: A hydrophilic trap (which may be the aqueous cavity within the inner vestibule), which favors polar and less lipophilic compounds, and a lipophilic trap (which may be the membrane phase itself, and/or lipophilic binding sites on the channel). Rescue from the hydrophilic and lipophilic traps can be promoted by alkalic and acidic extracellular pH, respectively. PMID:26441665

  12. Enhancing Access to Land Remote Sensing Data through Mainstream Social Media Channels

    NASA Astrophysics Data System (ADS)

    Sohre, T.; Maiersperger, T.

    2011-12-01

    Social media tools are changing the way that people discover information, communicate, and collaborate. Government agencies supporting the Land Remote Sensing user community have begun taking advantage of standard social media tools and capabilities. National Aeronautics and Space Administration (NASA) Earth Observing System (EOS) data centers have started providing outreach utilizing services including Facebook, Twitter, and YouTube videos. Really Simple Syndication (RSS) Feeds have become more standard means of sharing information, and a DataCasting tool was created as a NASA Technology Infusion effort to make RSS-based technology for accessing Earth Science information available. The United States Geological Survey (USGS) has also started using social media to allow the community access to news feeds and real-time earthquake alerts; listen to podcasts; get updates on new USGS publications, videos, and photographs; and more. Twitter feeds have been implemented in 2011 for the USGS Land Cover and Landsat user communities. In early 2011, the NASA Land Processes Distributed Active Archive Center (LP DAAC) user working group suggested the investigation of concepts for creating and distributing "bundles" of data, which would aggregate theme-based data sets from multiple sources. The LP DAAC is planning to explore the use of standard social bookmarking tools to support community developed bundles through the use of tools such as Delicious, Digg, or StumbleUpon. This concept would allow science users to organize and discover common links to data resources based on community developed tags, or a folksonomy. There are challenges that will need to be addressed such as maintaining the quality of tags but a social bookmarking system may have advantages over traditional search engines or formal ontologies for identifying and labeling various data sets relevant to a theme. As classification is done by the community of scientists who understand the data, the tagged data sets

  13. Energy-Efficiency Analysis of a Distributed Queuing Medium Access Control Protocol for Biomedical Wireless Sensor Networks in Saturation Conditions

    PubMed Central

    Otal, Begonya; Alonso, Luis; Verikoukis, Christos

    2011-01-01

    The aging population and the high quality of life expectations in our society lead to the need of more efficient and affordable healthcare solutions. For this reason, this paper aims for the optimization of Medium Access Control (MAC) protocols for biomedical wireless sensor networks or wireless Body Sensor Networks (BSNs). The hereby presented schemes always have in mind the efficient management of channel resources and the overall minimization of sensors’ energy consumption in order to prolong sensors’ battery life. The fact that the IEEE 802.15.4 MAC does not fully satisfy BSN requirements highlights the need for the design of new scalable MAC solutions, which guarantee low-power consumption to the maximum number of body sensors in high density areas (i.e., in saturation conditions). In order to emphasize IEEE 802.15.4 MAC limitations, this article presents a detailed overview of this de facto standard for Wireless Sensor Networks (WSNs), which serves as a link for the introduction and initial description of our here proposed Distributed Queuing (DQ) MAC protocol for BSN scenarios. Within this framework, an extensive DQ MAC energy-consumption analysis in saturation conditions is presented to be able to evaluate its performance in relation to IEEE 802.5.4 MAC in highly dense BSNs. The obtained results show that the proposed scheme outperforms IEEE 802.15.4 MAC in average energy consumption per information bit, thus providing a better overall performance that scales appropriately to BSNs under high traffic conditions. These benefits are obtained by eliminating back-off periods and collisions in data packet transmissions, while minimizing the control overhead. PMID:22319351

  14. George MacDonald's Estimate of Childhood

    ERIC Educational Resources Information Center

    Pridmore, John

    2007-01-01

    The nineteenth-century fantasy writer George MacDonald believed that "it is better to be a child in a green field than a knight of many orders." In this paper, I shall explore the bearing of this high estimate of childhood on spiritual education. MacDonald explores the spirituality of the child in his essay "A Sketch of Individual Development" and…

  15. MacIntyre, Rival Traditions and Education

    ERIC Educational Resources Information Center

    Stolz, Steven A.

    2016-01-01

    This paper critically discusses MacIntyre's thesis that education is essentially a contested concept. In order to contextualise my discussion, I discuss both whether rival educational traditions of education found in MacIntyre's work--which I refer to as instrumental and non-instrumental justifications of education--can be rationally resolved…

  16. A hybrid MAC protocol design for energy-efficient very-high-throughput millimeter wave, wireless sensor communication networks

    NASA Astrophysics Data System (ADS)

    Jian, Wei; Estevez, Claudio; Chowdhury, Arshad; Jia, Zhensheng; Wang, Jianxin; Yu, Jianguo; Chang, Gee-Kung

    2010-12-01

    This paper presents an energy-efficient Medium Access Control (MAC) protocol for very-high-throughput millimeter-wave (mm-wave) wireless sensor communication networks (VHT-MSCNs) based on hybrid multiple access techniques of frequency division multiplexing access (FDMA) and time division multiplexing access (TDMA). An energy-efficient Superframe for wireless sensor communication network employing directional mm-wave wireless access technologies is proposed for systems that require very high throughput, such as high definition video signals, for sensing, processing, transmitting, and actuating functions. Energy consumption modeling for each network element and comparisons among various multi-access technologies in term of power and MAC layer operations are investigated for evaluating the energy-efficient improvement of proposed MAC protocol.

  17. Changes in accessibility of cytoplasmic substances to the pore associated with activation of the cystic fibrosis transmembrane conductance regulator chloride channel.

    PubMed

    El Hiani, Yassine; Linsdell, Paul

    2010-10-15

    Opening of the cystic fibrosis transmembrane conductance regulator Cl(-) channel is dependent both on phosphorylation and on ATP binding and hydrolysis. However, the mechanisms by which these cytoplasmic regulatory factors open the Cl(-) channel pore are not known. We have used patch clamp recording to investigate the accessibility of cytoplasmically applied cysteine-reactive reagents to cysteines introduced along the length of the pore-lining sixth transmembrane region (TM6) of a cysteine-less variant of cystic fibrosis transmembrane conductance regulator. We find that methanethiosulfonate (MTS) reagents modify irreversibly cysteines substituted for TM6 residues Phe-337, Thr-338, Ser-341, Ile-344, Val-345, Met-348, Ala-349, Arg-352, and Gln-353 when applied to the cytoplasmic side of open channels. However, the apparent rate of modification by internal [2-sulfonatoethyl] methanethiosulfonate (MTSES), a negatively charged MTS reagent, is dependent on the activation state of the channels. In particular, cysteines introduced far along the axis of TM6 from the inside (T338C, S341C, I344C) showed no evidence of significant modification even after prolonged pretreatment of non-activated channels with internal MTSES. In contrast, cysteines introduced closer to the inside of TM6 (V345C, M348C) were readily modified in both activated and non-activated channels. Access of a permeant anion, Au(CN)(2)(-), to T338C was similarly dependent upon channel activation state. The pattern of MTS modification we observe allows us to designate different pore-lining amino acid side chains to distinct functional regions of the channel pore. One logical interpretation of these findings is that cytoplasmic access to residues at the narrowest region of the pore changes concomitant with activation. PMID:20675380

  18. Changes in Accessibility of Cytoplasmic Substances to the Pore Associated with Activation of the Cystic Fibrosis Transmembrane Conductance Regulator Chloride Channel*

    PubMed Central

    El Hiani, Yassine; Linsdell, Paul

    2010-01-01

    Opening of the cystic fibrosis transmembrane conductance regulator Cl− channel is dependent both on phosphorylation and on ATP binding and hydrolysis. However, the mechanisms by which these cytoplasmic regulatory factors open the Cl− channel pore are not known. We have used patch clamp recording to investigate the accessibility of cytoplasmically applied cysteine-reactive reagents to cysteines introduced along the length of the pore-lining sixth transmembrane region (TM6) of a cysteine-less variant of cystic fibrosis transmembrane conductance regulator. We find that methanethiosulfonate (MTS) reagents modify irreversibly cysteines substituted for TM6 residues Phe-337, Thr-338, Ser-341, Ile-344, Val-345, Met-348, Ala-349, Arg-352, and Gln-353 when applied to the cytoplasmic side of open channels. However, the apparent rate of modification by internal [2-sulfonatoethyl] methanethiosulfonate (MTSES), a negatively charged MTS reagent, is dependent on the activation state of the channels. In particular, cysteines introduced far along the axis of TM6 from the inside (T338C, S341C, I344C) showed no evidence of significant modification even after prolonged pretreatment of non-activated channels with internal MTSES. In contrast, cysteines introduced closer to the inside of TM6 (V345C, M348C) were readily modified in both activated and non-activated channels. Access of a permeant anion, Au(CN)2−, to T338C was similarly dependent upon channel activation state. The pattern of MTS modification we observe allows us to designate different pore-lining amino acid side chains to distinct functional regions of the channel pore. One logical interpretation of these findings is that cytoplasmic access to residues at the narrowest region of the pore changes concomitant with activation. PMID:20675380

  19. 33 CFR 100.35T05-0276 - Special Local Regulations for Marine Events; Potomac River, National Harbor Access Channel, MD.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Marine Events; Potomac River, National Harbor Access Channel, MD. 100.35T05-0276 Section 100.35T05-0276 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY REGATTAS AND MARINE PARADES SAFETY OF LIFE ON NAVIGABLE WATERS § 100.35T05-0276 Special Local Regulations for Marine Events;...

  20. 33 CFR 100.35T05-0276 - Special Local Regulations for Marine Events; Potomac River, National Harbor Access Channel, MD.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Marine Events; Potomac River, National Harbor Access Channel, MD. 100.35T05-0276 Section 100.35T05-0276 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY REGATTAS AND MARINE PARADES SAFETY OF LIFE ON NAVIGABLE WATERS § 100.35T05-0276 Special Local Regulations for Marine Events;...

  1. Micromechanics Analysis Code (MAC). User Guide: Version 2.0

    NASA Technical Reports Server (NTRS)

    Wilt, T. E.; Arnold, S. M.

    1996-01-01

    The ability to accurately predict the thermomechanical deformation response of advanced composite materials continues to play an important role in the development of these strategic materials. Analytical models that predict the effective behavior of composites are used not only by engineers performing structural analysis of large-scale composite components but also by material scientists in developing new material systems. For an analytical model to fulfill these two distinct functions it must be based on a micromechanics approach which utilizes physically based deformation and life constitutive models and allows one to generate the average (macro) response of a composite material given the properties of the individual constituents and their geometric arrangement. Here the user guide for the recently developed, computationally efficient and comprehensive micromechanics analysis code's (MAC) who's predictive capability rests entirely upon the fully analytical generalized method of cells (GMC), micromechanics model is described. MAC is a versatile form of research software that 'drives' the double or triply periodic micromechanics constitutive models based upon GMC. MAC enhances the basic capabilities of GMC by providing a modular framework wherein (1) various thermal, mechanical (stress or strain control) and thermomechanical load histories can be imposed, (2) different integration algorithms may be selected, (3) a variety of constituent constitutive models may be utilized and/or implemented, and (4) a variety of fiber and laminate architectures may be easily accessed through their corresponding representative volume elements.

  2. Micromechanics Analysis Code (MAC) User Guide: Version 1.0

    NASA Technical Reports Server (NTRS)

    Wilt, T. E.; Arnold, S. M.

    1994-01-01

    The ability to accurately predict the thermomechanical deformation response of advanced composite materials continues to play an important role in the development of these strategic materials. Analytical models that predict the effective behavior of composites are used not only by engineers performing structural analysis of large-scale composite components but also by material scientists in developing new material systems. For an analytical model to fulfill these two distinct functions it must be based on a micromechanics approach which utilizes physically based deformation and life constitutive models and allows one to generate the average (macro) response of a composite material given the properties of the individual constituents and their geometric arrangement. Here the user guide for the recently developed, computationally efficient and comprehensive micromechanics analysis code, MAC, who's predictive capability rests entirely upon the fully analytical generalized method of cells, GMC, micromechanics model is described. MAC is a versatile form of research software that 'drives' the double or triple ply periodic micromechanics constitutive models based upon GMC. MAC enhances the basic capabilities of GMC by providing a modular framework wherein (1) various thermal, mechanical (stress or strain control), and thermomechanical load histories can be imposed; (2) different integration algorithms may be selected; (3) a variety of constituent constitutive models may be utilized and/or implemented; and (4) a variety of fiber architectures may be easily accessed through their corresponding representative volume elements.

  3. Theoretical Characterization of Substrate Access/Exit Channels in the Human Cytochrome P450 3A4 Enzyme: Involvement of Phenylalanine Residues in the Gating Mechanism

    PubMed Central

    2009-01-01

    The human cytochrome P450 3A4 mono-oxygenates ∼50% of all drugs. Its substrates/products enter/leave the active site by access/exit channels. Here, we perform steered molecular dynamics simulations, pulling the products temazepam and testosterone-6βOH out of the P450 3A4 enzyme in order to identify the preferred substrate/product pathways and their gating mechanism. We locate six different egress pathways of products from the active site with different exit preferences for the two products and find that there is more than just one access/exit channel in CYP3A4. The so-called solvent channel manifests the largest opening for both tested products, thereby identifying this channel as a putative substrate channel. Most channels consist of one or two π-stacked phenylalanine residues that serve as gate keepers. The oxidized drug breaks the hydrophobic interactions of the gating residues and forms mainly hydrophobic contacts with the gate. We argue that product exit preferences in P450s are regulated by protein−substrate specificity. PMID:19728720

  4. Exploring the Structure of the Voltage-gated Na+ Channel by an Engineered Drug Access Pathway to the Receptor Site for Local Anesthetics*

    PubMed Central

    Lukacs, Peter; Gawali, Vaibhavkumar S.; Cervenka, Rene; Ke, Song; Koenig, Xaver; Rubi, Lena; Zarrabi, Touran; Hilber, Karlheinz; Stary-Weinzinger, Anna; Todt, Hannes

    2014-01-01

    Despite the availability of several crystal structures of bacterial voltage-gated Na+ channels, the structure of eukaryotic Na+ channels is still undefined. We used predictions from available homology models and crystal structures to modulate an external access pathway for the membrane-impermeant local anesthetic derivative QX-222 into the internal vestibule of the mammalian rNaV1.4 channel. Potassium channel-based homology models predict amino acid Ile-1575 in domain IV segment 6 to be in close proximity to Lys-1237 of the domain III pore-loop selectivity filter. The mutation K1237E has been shown previously to increase the diameter of the selectivity filter. We found that an access pathway for external QX-222 created by mutations of Ile-1575 was abolished by the additional mutation K1237E, supporting the notion of a close spatial relationship between sites 1237 and 1575. Crystal structures of bacterial voltage-gated Na+ channels predict that the side chain of rNaV1.4 Trp-1531 of the domain IV pore-loop projects into the space between domain IV segment 6 and domain III pore-loop and, therefore, should obstruct the putative external access pathway. Indeed, mutations W1531A and W1531G allowed for exceptionally rapid access of QX-222. In addition, W1531G created a second non-selective ion-conducting pore, bypassing the outer vestibule but probably merging into the internal vestibule, allowing for control by the activation gate. These data suggest a strong structural similarity between bacterial and eukaryotic voltage-gated Na+ channels. PMID:24947510

  5. Crystal Structure of Inhibitor-Bound P450BM-3 Reveals Open Conformation of Substrate Access Channel

    SciTech Connect

    Haines, Donovan C.; Chen, Baozhi; Tomchick, Diana R.; Bondlela, Muralidhar; Hegde, Amita; Machius, Mischa; Peterson, Julian A.

    2008-08-19

    P450BM-3 is an extensively studied P450 cytochrome that is naturally fused to a cytochrome P450 reductase domain. Crystal structures of the heme domain of this enzyme have previously generated many insights into features of P450 structure, substrate binding specificity, and conformational changes that occur on substrate binding. Although many P450s are inhibited by imidazole, this compound does not effectively inhibit P450BM-3. {omega}-Imidazolyl fatty acids have previously been found to be weak inhibitors of the enzyme and show some unusual cooperativity with the substrate lauric acid. We set out to improve the properties of these inhibitors by attaching the {omega}-imidazolyl fatty acid to the nitrogen of an amino acid group, a tactic that we used previously to increase the potency of substrates. The resulting inhibitors were significantly more potent than their parent compounds lacking the amino acid group. A crystal structure of one of the new inhibitors bound to the heme domain of P450BM-3 reveals that the mode of interaction of the amino acid group with the enzyme is different from that previously observed for acyl amino acid substrates. Further, required movements of residues in the active site to accommodate the imidazole group provide an explanation for the low affinity of imidazole itself. Finally, the previously observed cooperativity with lauric acid is explained by a surprisingly open substrate-access channel lined with hydrophobic residues that could potentially accommodate lauric acid in addition to the inhibitor itself.

  6. A MAC Protocol for Medical Monitoring Applications of Wireless Body Area Networks

    PubMed Central

    Shu, Minglei; Yuan, Dongfeng; Zhang, Chongqing; Wang, Yinglong; Chen, Changfang

    2015-01-01

    Targeting the medical monitoring applications of wireless body area networks (WBANs), a hybrid medium access control protocol using an interrupt mechanism (I-MAC) is proposed to improve the energy and time slot utilization efficiency and to meet the data delivery delay requirement at the same time. Unlike existing hybrid MAC protocols, a superframe structure with a longer length is adopted to avoid unnecessary beacons. The time slots are mostly allocated to nodes with periodic data sources. Short interruption slots are inserted into the superframe to convey the urgent data and to guarantee the real-time requirements of these data. During these interruption slots, the coordinator can break the running superframe and start a new superframe. A contention access period (CAP) is only activated when there are more data that need to be delivered. Experimental results show the effectiveness of the proposed MAC protocol in WBANs with low urgent traffic. PMID:26046596

  7. User's manual for MacPASCO

    NASA Technical Reports Server (NTRS)

    Lucas, S. H.; Davis, R. C.

    1992-01-01

    A user's manual is presented for MacPASCO, which is an interactive, graphic, preprocessor for panel design. MacPASCO creates input for PASCO, an existing computer code for structural analysis and sizing of longitudinally stiffened composite panels. MacPASCO provides a graphical user interface which simplifies the specification of panel geometry and reduces user input errors. The user draws the initial structural geometry and reduces user input errors. The user draws the initial structural geometry on the computer screen, then uses a combination of graphic and text inputs to: refine the structural geometry; specify information required for analysis such as panel load and boundary conditions; and define design variables and constraints for minimum mass optimization. Only the use of MacPASCO is described, since the use of PASCO has been documented elsewhere.

  8. Cleanup MAC and MBA code ATP

    SciTech Connect

    Russell, V.K.

    1994-10-17

    The K Basins Materials Accounting (MAC) and Material Balance (MBA) database system had some minor code cleanup performed to its code. This ATP describes how the code was to be tested to verify its correctness.

  9. A Conversation with Patricia MacLachlan.

    ERIC Educational Resources Information Center

    Austin, Patricia

    1996-01-01

    Contains an interview with Patricia MacLachlan, former teacher and author of the award-winning novel "Sarah, Plain and Tall" about her views on the latest trends in teaching reading and writing to children. (TB)

  10. Energy Efficient Medium Access Control Protocol for Clustered Wireless Sensor Networks with Adaptive Cross-Layer Scheduling.

    PubMed

    Sefuba, Maria; Walingo, Tom; Takawira, Fambirai

    2015-01-01

    This paper presents an Energy Efficient Medium Access Control (MAC) protocol for clustered wireless sensor networks that aims to improve energy efficiency and delay performance. The proposed protocol employs an adaptive cross-layer intra-cluster scheduling and an inter-cluster relay selection diversity. The scheduling is based on available data packets and remaining energy level of the source node (SN). This helps to minimize idle listening on nodes without data to transmit as well as reducing control packet overhead. The relay selection diversity is carried out between clusters, by the cluster head (CH), and the base station (BS). The diversity helps to improve network reliability and prolong the network lifetime. Relay selection is determined based on the communication distance, the remaining energy and the channel quality indicator (CQI) for the relay cluster head (RCH). An analytical framework for energy consumption and transmission delay for the proposed MAC protocol is presented in this work. The performance of the proposed MAC protocol is evaluated based on transmission delay, energy consumption, and network lifetime. The results obtained indicate that the proposed MAC protocol provides improved performance than traditional cluster based MAC protocols. PMID:26393608

  11. Energy Efficient Medium Access Control Protocol for Clustered Wireless Sensor Networks with Adaptive Cross-Layer Scheduling

    PubMed Central

    Sefuba, Maria; Walingo, Tom; Takawira, Fambirai

    2015-01-01

    This paper presents an Energy Efficient Medium Access Control (MAC) protocol for clustered wireless sensor networks that aims to improve energy efficiency and delay performance. The proposed protocol employs an adaptive cross-layer intra-cluster scheduling and an inter-cluster relay selection diversity. The scheduling is based on available data packets and remaining energy level of the source node (SN). This helps to minimize idle listening on nodes without data to transmit as well as reducing control packet overhead. The relay selection diversity is carried out between clusters, by the cluster head (CH), and the base station (BS). The diversity helps to improve network reliability and prolong the network lifetime. Relay selection is determined based on the communication distance, the remaining energy and the channel quality indicator (CQI) for the relay cluster head (RCH). An analytical framework for energy consumption and transmission delay for the proposed MAC protocol is presented in this work. The performance of the proposed MAC protocol is evaluated based on transmission delay, energy consumption, and network lifetime. The results obtained indicate that the proposed MAC protocol provides improved performance than traditional cluster based MAC protocols. PMID:26393608

  12. AeroMACS System Characterization and Demonstrations

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.; Apaza, Rafael D.; Dimond, Robert P.

    2013-01-01

    This The Aeronautical Mobile Airport Communications System (AeroMACS) is being developed to provide a new broadband wireless communications capability for safety critical communications in the airport surface domain, providing connectivity to aircraft and other ground vehicles as well as connections between other critical airport fixed assets. AeroMACS development has progressed from requirements definition through technology definition, prototype deployment and testing, and now into national and international standards development. The first prototype AeroMACS system has been deployed at the Cleveland Hopkins International Airport (CLE) and the adjacent NASA Glenn Research Center (GRC). During the past 3 years, extensive technical testing has taken place to characterize the performance of the AeroMACS prototype and provide technical support for the standards development process. The testing has characterized AeroMACS link and network performance over a variety of conditions for both fixed and mobile data transmission and has included basic system performance testing and fixed and mobile applications testing. This paper provides a summary of the AeroMACS performance testing and the status of standardization activities that the testing supports.

  13. AeroMACS System Characterization and Demonstrations

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.; Apaza, Rafael D.; Dimond, Robert P.

    2013-01-01

    The Aeronautical Mobile Airport Communications System (AeroMACS) is being developed to provide a new broadband wireless communications capability for safety critical communications in the airport surface domain, providing connectivity to aircraft and other ground vehicles as well as connections between other critical airport fixed assets. AeroMACS development has progressed from requirements definition through technology definition, prototype deployment and testing, and now into national and international standards development. The first prototype AeroMACS system has been deployed at the Cleveland Hopkins International Airport (CLE) and the adjacent NASA Glenn Research Center (GRC). During the past three years, extensive technical testing has taken place to characterize the performance of the AeroMACS prototype and provide technical support for the standards development process. The testing has characterized AeroMACS link and network performance over a variety of conditions for both fixed and mobile data transmission and has included basic system performance testing and fixed and mobile applications testing. This paper provides a summary of the AeroMACS performance testing and the status of standardization activities that the testing supports.

  14. AeroMACS system characterization and demonstrations

    NASA Astrophysics Data System (ADS)

    Kerczewski, R. J.; Apaza, R. D.; Dimond, R. P.

    This The Aeronautical Mobile Airport Communications System (AeroMACS) is being developed to provide a new broadband wireless communications capability for safety critical communications in the airport surface domain, providing connectivity to aircraft and other ground vehicles as well as connections between other critical airport fixed assets. AeroMACS development has progressed from requirements definition through technology definition, prototype deployment and testing, and now into national and international standards development. The first prototype AeroMACS system has been deployed at the Cleveland Hopkins International Airport (CLE) and the adjacent NASA Glenn Research Center (GRC). During the past three years, extensive technical testing has taken place to characterize the performance of the AeroMACS prototype and provide technical support for the standards development process. The testing has characterized AeroMACS link and network performance over a variety of conditions for both fixed and mobile data transmission and has included basic system performance testing and fixed and mobile applications testing. This paper provides a summary of the AeroMACS performance testing and the status of standardization activities that the testing supports.

  15. The Mac Internet Tour Guide: Cruising the Internet the Easy Way. [First Edition.

    ERIC Educational Resources Information Center

    Fraase, Michael

    Published exclusively for MacIntosh computer users, this guide provides an overview of Internet resources for new and experienced users. E-mail, file transfer, and decompression software used to access the resources are included on a 800k, 3.5 inch disk. The following chapters are included: (1) "What Is the Internet" covers finding your way…

  16. Chip-interleaved optical code division multiple access relying on a photon-counting iterative successive interference canceller for free-space optical channels.

    PubMed

    Zhou, Xiaolin; Zheng, Xiaowei; Zhang, Rong; Hanzo, Lajos

    2013-07-01

    In this paper, we design a novel Poisson photon-counting based iterative successive interference cancellation (SIC) scheme for transmission over free-space optical (FSO) channels in the presence of both multiple access interference (MAI) as well as Gamma-Gamma atmospheric turbulence fading, shot-noise and background light. Our simulation results demonstrate that the proposed scheme exhibits a strong MAI suppression capability. Importantly, an order of magnitude of BER improvements may be achieved compared to the conventional chip-level optical code-division multiple-access (OCDMA) photon-counting detector. PMID:23842379

  17. GREEN-MAC-LCCP: a tool for assessing the life cycle climate performance of MAC systems.

    PubMed

    Papasavva, Stella; Hill, William R; Andersen, Stephen O

    2010-10-01

    In 2008, 95% of the vehicle fleet in the developed countries and 80% of fleet in the developing countries were equipped with mobile air conditioning systems (MACs). Greenhouse gases (GHGs) are emitted due to refrigerant leakage (direct emissions) and due to the energy consumed by MACs operation (indirect emissions). In response to reducing the global warming impact of MACs, policy makers and the industry are investigating alternative refrigerant systems that use low global warming potential (GWP) refrigerants. The GREEN-MAC-LCCP model assesses the direct and indirect CO(2) equivalent emissions related to MACs usage, as well as those associated with the production, use and disposal of alternative refrigerants and MACs components. This model provides a platform for simple data input and provides an output summary as well as details that can be analyzed in a custom fashion by the user. It provides engineers and policy makers a state-of-the-art tool, based on sound engineering data and methods, in order to facilitate the process of evaluating alternate refrigerants with low lifecycle global warming impact as well as providing the total impact of any MACs on the environment. It has been recognized as the standard of the MACs industry. PMID:20812721

  18. Binding of the antitubercular pro-drug isoniazid in the heme access channel of catalase-peroxidase (KatG). A combined structural and metadynamics investigation.

    PubMed

    Vidossich, Pietro; Loewen, Peter C; Carpena, Xavi; Fiorin, Giacomo; Fita, Ignacio; Rovira, Carme

    2014-03-20

    Isonicotinic acid hydrazide (isoniazid or INH) is a front line antitubercular pro-drug that is converted to its active form, isonicotinyl-NAD, by the bacterial catalase-peroxidase KatG. Understanding the role of KatG in the INH activation process has been hampered by a lack of knowledge of the actual drug binding site. In this work, we have investigated the binding of INH in the main access channel of KatG with a combination of molecular dynamics, using an enhanced-sampling technique (metadynamics), X-ray crystallography, and site-directed mutagenesis. The metadynamics simulations show that there are several weak drug binding sites along the access channel. Moreover, the simulations evidence that complete entrance to the heme active site is impeded by an aspartate residue (D141) located above the heme. This has been confirmed by structural and functional analysis of the D141A mutant, leading to the first X-ray crystallography evidence of INH at the heme access channel. PMID:24568093

  19. On the Achievable Efficiency-Fairness Tradeoff in Utility-Optimal MAC Protocols

    NASA Astrophysics Data System (ADS)

    Lee, Jang-Won; Chiang, Mung; Calderbank, A. Robert

    We use the network utility maximization (NUM) framework to create an efficient and fair medium access control (MAC) protocol for wireless networks. By adjusting the parameters in the utility objective functions of NUM problems, we control the tradeoff between efficiency and fairness of radio resource allocation through a rigorous and systematic design. In this paper, we propose a scheduling-based MAC protocol. Since it provides an upper-bound on the achievable performance, it establishes the optimality benchmarks for comparison with other algorithms in related work.

  20. HFGMC Enhancement of MAC/GMC

    NASA Technical Reports Server (NTRS)

    Arnold, Steven M.; Aboudi, Jacob; Pindera, Marek-Jerzy; Bednarcyk, Brett A.

    2006-01-01

    Additional information about a mathematical model denoted the high-fidelity generalized method of cells (HFGMC) and implementation of the HFGMC within version 4.0 of the MAC/GMC software has become available. MAC/GMC (Micromechanics Analysis Code With Generalized Method of Cells) was a topic of several prior NASA Tech Briefs articles, version 4.0 having been described in "Comprehensive Micromechanics-Analysis Code - Version 4.0" (LEW-17495-1), NASA Tech Briefs, Vol. 29, No. 9 (September 2005), page 54. MAC/GMC predicts elastic and inelastic thermomechanical responses of composite materials. MAC/GMC utilizes the generalized method of cells (GMC) - a model of micromechanics that predicts macroscopic responses of a composite material as functions of the properties, sizes, shapes, and responses of its constituents (e.g., matrix and fibers). The accuracy of the GMC is limited by neglect of coupling between normal and shear stresses. The HFGMC was developed by combining elements of the GMC and a related model, denoted the higher-order theory for functionally graded materials (HOTFGM), that can account for this coupling. Hence, the HFGMC enables simulation of stress and strain with greater accuracy. Some alterations of the MAC/GMC data structure were necessitated by the greater computational complexity of the HFGMC.

  1. Shared decision making after MacIntyre.

    PubMed

    Tilburt, Jon

    2011-04-01

    This paper explores the practical consequences that Enlightenment ideals had on morality as it applies to clinical practice, using Alisdair MacIntyre's conceptualization and critique of the Enlightenment as its reference point. Taking the perspective of a practicing clinician, I critically examine the historical origins of ideas that made shared decision making (SDM) a necessary and ideal model of clinician-patient relationship. I then build on MacIntyre's critique of Enlightenment thought and examine its implications for conceptions of shared decision-making that use an Enlightenment justification, as well as examining contemporary threats to SDM that the Enlightenment made possible. I conclude by offering an alternative framing of SDM that fits with the clinician's duty to act on behalf of and along with patients but that avoids the tenuous Enlightenment assumptions that MacIntyre's work so vocally critiques. PMID:21378085

  2. Geospatial Multi-Agency Coordination (GeoMAC) wildland fire perimeters, 2008

    USGS Publications Warehouse

    Walters, Sandra P.; Schneider, Norma J.; Guthrie, John D.

    2011-01-01

    The Geospatial Multi-Agency Coordination (GeoMAC) has been collecting and storing data on wildland fire perimeters since August 2000. The dataset presented via this U.S. Geological Survey Data Series product contains the GeoMAC wildland fire perimeter data for the calendar year 2008, which are based upon input from incident intelligence sources, Global Positioning System (GPS) data, and infrared (IR) imagery. Wildland fire perimeter data are obtained from the incidents, evaluated for completeness and accuracy, and processed to reflect consistent field names and attributes. After a quality check, the perimeters are loaded to GeoMAC databases, which support the GeoMAC Web application for access by wildland fire managers and the public. The wildland fire perimeters are viewed through the Web application. The data are subsequently archived according to year and state and are made available for downloading through the Internet in shapefile and Keyhole Markup Language (KML) format. These wildland fire perimeter data are also retained for historical, planning, and research purposes. The datasets that pertain to this report can be found on the Rocky Mountain Geographic Science Center HTTP site at http://rmgsc.cr.usgs.gov/outgoing/GeoMAC/historic_fire_data/. The links are also provided on the sidebar.

  3. MAC/GMC 4.0 User's Manual: Example Problem Manual. Volume 3

    NASA Technical Reports Server (NTRS)

    Bednarcyk, Brett A.; Arnold, Steven M.

    2002-01-01

    This document is the third volume in the three volume set of User's Manuals for the Micromechanics Analysis Code with Generalized Method of Cells Version 4.0 (MAC/GMC 4.0). Volume 1 is the Theory Manual, Volume 2 is the Keywords Manual, and this document is the Example Problems Manual. MAC/GMC 4.0 is a composite material and laminate analysis software program developed at the NASA Glenn Research Center. It is based on the generalized method of cells (GMC) micromechanics theory, which provides access to the local stress and strain fields in the composite material. This access grants GMC the ability to accommodate arbitrary local models for inelastic material behavior and various types of damage and failure analysis. MAC/GMC 4.0 has been built around GMC to provide the theory with a user-friendly framework, along with a library of local inelastic, damage, and failure models. Further, application of simulated thermo-mechanical loading, generation of output results, and selection of architectures to represent the composite material, have been automated in MAC/GMC 4.0. Finally, classical lamination theory has been implemented within MAC/GMC 4.0 wherein GMC is used to model the composite material response of each ply. Consequently, the full range of GMC composite material capabilities is available for analysis of arbitrary laminate configurations as well. This volume provides in-depth descriptions of 43 example problems, which were specially designed to highlight many of the most important capabilities of the code. The actual input files associated with each example problem are distributed with the MAC/GMC 4.0 software; thus providing the user with a convenient starting point for their own specialized problems of interest.

  4. MAC/GMC 4.0 User's Manual: Keywords Manual. Volume 2

    NASA Technical Reports Server (NTRS)

    Bednarcyk, Brett A.; Arnold, Steven M.

    2002-01-01

    This document is the second volume in the three volume set of User's Manuals for the Micromechanics Analysis Code with Generalized Method of Cells Version 4.0 (MAC/GMC 4.0). Volume 1 is the Theory Manual, this document is the Keywords Manual, and Volume 3 is the Example Problem Manual. MAC/GMC 4.0 is a composite material and laminate analysis software program developed at the NASA Glenn Research Center. It is based on the generalized method of cells (GMC) micromechanics theory, which provides access to the local stress and strain fields in the composite material. This access grants GMC the ability to accommodate arbitrary local models for inelastic material behavior and various types of damage and failure analysis. MAC/GMC 4.0 has been built around GMC to provide the theory with a user-friendly framework, along with a library of local inelastic, damage, and failure models. Further, applications of simulated thermo-mechanical loading, generation of output results, and selection of architectures to represent the composite material have been automated in MAC/GMC 4.0. Finally, classical lamination theory has been implemented within MAC/GMC 4.0 wherein GMC is used to model the composite material response of each ply. Consequently, the full range of GMC composite material capabilities is available for analysis of arbitrary laminate configurations as well. This volume describes the basic information required to use the MAC/GMC 4.0 software, including a 'Getting Started' section, and an in-depth description of each of the 22 keywords used in the input file to control the execution of the code.

  5. MAC-bridging for multi-PHYs communication in BAN.

    PubMed

    Ullah, Sana; Khan, Pervez; Ullah, Niamat; Kwak, Kyung Sup

    2010-01-01

    Body Area Network (BAN) is a collection of low-power, miniaturised, and intelligent sensor nodes that are used for unobtrusive and ambulatory health monitoring of a patient without any additional constraints. These nodes operate on different frequency bands or Multiple Physical Layers (Multi-PHYs). Additionally, some BAN applications demand a logical connection between different nodes working on different Multi-PHYs. In this paper, the idea of controlling Multi-PHYs using one MAC protocol is introduced. Unlike existing procedures where different nodes working on different channels are connected at the link layer bridging/switching, the proposed procedure called bridging logically connects them at the MAC layer. In other words, the bridge is used to relay or filter packets between different PHYs in the same BAN. Numerical approximations are presented to analyze the stochastic behaviour of the bridges, all of them having Multi-PHYs interfaces. The MICS and the ISM bands are regarded as PHY1 and PHY2, respectively. The performance results are presented for PHY2 (given that data is already received from PHY1) in terms of probability of successful transmission, number of failed requests, power consumption, and delay. Simulations are conducted to validate the analytical results. It can be seen that the deployment of multiple bridges along with the corresponding nodes allows Multi-PHYs communication with high transmission probability, low power consumption, and tolerable delay. PMID:22163447

  6. MAC protocol for an ATM-based SuperPON

    NASA Astrophysics Data System (ADS)

    Angelopoulos, John D.; Koulouris, John; Fragoulopoulos, Stratos K.

    1996-11-01

    Developments in optical amplifiers and the tendency towards fewer and larger switching stages made feasible and desirable the concept of SuperPONs with a range of 100km. Up to 15000 residential customers can share the SuperPON on a TDMA basis lowering the cost of access to B-ISDN services. Tree PONs require a MAC protocol to arbitrate the access to upstream slots among the competing customer ATM cells in a dynamic and efficient way. The protocol presented in this work combines different access mechanisms according to service quality requirements. All bursty traffic is manipulated transparently using a reservation approach with closed loop control so as to handle the unpredictability of arrivals. In contrast, voice, N-ISDN and other delay sensitive services are provided with unsolicited access permits. In addition, composite cells offered quasi- synchronous permits are used to support STM legacy traffic without echo-cancellers. So, ABR traffic which is delay tolerant and more cost sensitive, can and should be concentrated with full exploitation of multiplexing gain prospects. The permit distribution algorithm focuses on cell spacing, control of CDV, almost jitter free access for synchronous traffic and efficiency for ABR traffic.

  7. Design and implementation of integrated MAC protocol with SR/NSR-ONU supporting the burst traffic over ATM-PON

    NASA Astrophysics Data System (ADS)

    Jang, Jongwook; Jang, SeongHo; Lee, Dae-bong

    2002-08-01

    In this paper, we proposed the request-counter MAC protocol for a broadband access network using an ATM-PON supporting CBR/rtVBR, nrtVBR, UBR and ABR traffic. For this, we present grant field format, minislot format, and dynamic bandwidth allocation algorithm. The proposed MAC protocol applies the different priority to permit distribution process. CBR/rtVBR traffic, with the stringent requirements on CDV or delay, is allocated prior to any other traffic class. nrtVBR traffic such as Internet traffic, which has non-strict CDV or delay criteria, uses flexibly the available bandwidth. UBR traffic is allocated with lowest priority for the remaining capacity. The performance of proposed MAC protocol is evaluated in terms of 1-point CDV with various offered load. From the simulation result, we have confirmed that our proposed scheme can reduce the average cell delay in comparison to that of conventional MAC schemes.

  8. Ion channel regulation by phosphoinositides analyzed with VSPs—PI(4,5)P2 affinity, phosphoinositide selectivity, and PI(4,5)P2 pool accessibility

    PubMed Central

    Rjasanow, Alexandra; Leitner, Michael G.; Thallmair, Veronika; Halaszovich, Christian R.; Oliver, Dominik

    2015-01-01

    The activity of many proteins depends on the phosphoinositide (PI) content of the membrane. E.g., dynamic changes of the concentration of PI(4,5)P2 are cellular signals that regulate ion channels. The susceptibility of a channel to such dynamics depends on its affinity for PI(4,5)P2. Yet, measuring affinities for endogenous PIs has not been possible directly, but has relied largely on the response to soluble analogs, which may not quantitatively reflect binding to native lipids. Voltage-sensitive phosphatases (VSPs) turn over PI(4,5)P2 to PI(4)P when activated by depolarization. In combination with voltage-clamp electrophysiology VSPs are useful tools for rapid and reversible depletion of PI(4,5)P2. Because cellular PI(4,5)P2 is resynthesized rapidly, steady state PI(4,5)P2 changes with the degree of VSP activation and thus depends on membrane potential. Here we show that titration of endogenous PI(4,5)P2 with Ci-VSP allows for the quantification of relative PI(4,5)P2 affinities of ion channels. The sensitivity of inward rectifier and voltage-gated K+ channels to Ci-VSP allowed for comparison of PI(4,5)P2 affinities within and across channel subfamilies and detected changes of affinity in mutant channels. The results also reveal that VSPs are useful only for PI effectors with high binding specificity among PI isoforms, because PI(4,5)P2 depletion occurs at constant overall PI level. Thus, Kir6.2, a channel activated by PI(4,5)P2 and PI(4)P was insensitive to VSP. Surprisingly, despite comparable PI(4,5)P2 affinity as determined by Ci-VSP, the Kv7 and Kir channel families strongly differed in their sensitivity to receptor-mediated depletion of PI(4,5)P2. While Kv7 members were highly sensitive to activation of PLC by Gq-coupled receptors, Kir channels were insensitive even when PI(4,5)P2 affinity was lowered by mutation. We hypothesize that different channels may be associated with distinct pools of PI(4,5)P2 that differ in their accessibility to PLC and VSPs. PMID

  9. Structural and dynamic basis of human cytochrome P450 7B1: a survey of substrate selectivity and major active site access channels.

    PubMed

    Cui, Ying-Lu; Zhang, Ji-Long; Zheng, Qing-Chuan; Niu, Rui-Juan; Xu, Yu; Zhang, Hong-Xing; Sun, Chia-Chung

    2013-01-01

    Cytochrome P450 (CYP) 7B1 is a steroid cytochrome P450 7α-hydroxylase that has been linked directly with bile salt synthesis and hereditary spastic paraplegia type 5 (SPG5). The enzyme provides the primary metabolic route for neurosteroids dehydroepiandrosterone (DHEA), cholesterol derivatives 25-hydroxycholesterol (25-HOChol), and other steroids such as 5α-androstane-3β,17β-diol (anediol), and 5α-androstene-3β,17β-diol (enediol). A series of investigations including homology modeling, molecular dynamics (MD), and automatic docking, combined with the results of previous experimental site-directed mutagenesis studies and access channels analysis, have identified the structural features relevant to the substrate selectivity of CYP7B1. The results clearly identify the dominant access channels and critical residues responsible for ligand binding. Both binding free energy analysis and total interaction energy analysis are consistent with the experimental conclusion that 25-HOChol is the best substrate. According to 20 ns MD simulations, the Phe cluster residues that lie above the active site, particularly Phe489, are proposed to merge the active site with the adjacent channel to the surface and accommodate substrate binding in a reasonable orientation. The investigation of CYP7B1-substrate binding modes provides detailed insights into the poorly understood structural features of human CYP7B1 at the atomic level, and will be valuable information for drug development and protein engineering. PMID:23180418

  10. An Interview with Peter MacDonald.

    ERIC Educational Resources Information Center

    American Indian Journal, 1979

    1979-01-01

    Peter MacDonald, Chairman of the Navajo Nation, the largest tribe in the United States speaks to such issues as energy development/management, oil companies, Navajo-Hopi relocation legislation, traditionalism, and the role of the Council of Energy Resource Tribes. (RTS)

  11. Lifetime tests for MAC vertex chamber

    SciTech Connect

    Nelson, H.N.

    1986-07-01

    A vertex chamber for MAC was proposed to increase precision in the measurement of the B hadron and tau lepton lifetimes. Thin-walled aluminized mylar drift tubes were used for detector elements. A study of radiation hardness was conducted under the conditions of the proposed design using different gases and different operating conditions. (LEW)

  12. Results from the MAC Vertex chamber

    SciTech Connect

    Nelson, H.N.

    1987-05-01

    The design, construction, and performance characteristics of a high precision gaseous drift chamber made of thin walled proportional tubes are described. The device achieved an average spatial resolution of 45 ..mu..m in use for physics analysis with the MAC detector. The B-lifetime result obtained with this chamber is discussed.

  13. The MacArthur Fellows Look Back.

    ERIC Educational Resources Information Center

    Cox, June; Daniel, Neil

    1984-01-01

    The article describes replies to a questionnaire by recipients of the MacArthur Fellows Program, an award given to individuals with uncommon abilities across a wide spectrum of creative pursuits. Replies touch on school and family backgrounds, acceleration, importance of grades, recognition of achievement, extracurricular activities, and…

  14. Exposure histories of lunar meteorites - ALHA81005, MAC88104, MAC88105, and Y791197

    NASA Technical Reports Server (NTRS)

    Nishiizumi, K.; Arnold, J. R.; Klein, J.; Fink, D.; Middleton, R.; Kubik, P. W.; Sharma, P.; Elmore, D.; Reedy, R. C.

    1991-01-01

    The cosmogenic radionuclides Ca-41, Cl-36, Al-26, and Be-10 in the Allan Hills 81005, MacAlpine Hills 88104, MacAlpine Hills 88105, and Yamato 791197 meteorites were measured by accelerator mass spectrometry. Mn-53 in Allan Hills 81005 and Yamato 791197 was measured by neutron activation. These four lunar meteorites experienced similar histories. They were ejected from near the surface of the moon ranging in depth down to 400 g/sq cm and had very short transition times (less than 0.1 Ma) from the moon to the earth. A comparison of the cosmogenic nuclide concentrations in MacAlpine Hills 88104 and MacAlpine Hills 88105 clearly indicates that they are a pair from the same fall.

  15. Exploring accessibility of structural elements of the mammalian 40S ribosomal mRNA entry channel at various steps of translation initiation.

    PubMed

    Sharifulin, Dmitri E; Bartuli, Yulia S; Meschaninova, Maria I; Ven'yaminova, Aliya G; Graifer, Dmitri M; Karpova, Galina G

    2016-10-01

    In this work, we studied how the accessibility of structural elements of the mammalian 40S ribosomal mRNA entry channel, ribosomal protein (rp) uS3 and helix (h) 16 of the 18S rRNA, changes upon the translation initiation. In particular, we examined the accessibility of rp uS3 for binding of unstructured RNAs and of riboses in h16 towards attack with benzoyl cyanide (BzCN) in complexes assembled in rabbit reticulocyte lysate utilizing synthetic oligoribonucleotides as well as full-length and truncated up to the initiation AUG codon hepatitis C virus IRES as model mRNAs. With both mRNA types, the rp uS3 peptide recognizing single-stranded RNAs was shown to become shielded only in those 48S preinitiation complexes (PICs) that contained eIF3j bound to 40S subunit in the area between the decoding site and the mRNA entry channel. Chemical probing with BzCN revealed that h16 in the 48S PICs containing eIF3j or scanning factor DHX29 is strongly shielded; the effect was observed with all the mRNAs used, and h16 remained protected as well in 80S post-initiation complexes lacking these factors. Altogether, the obtained results allowed us to suggest that eIF3j bound at the 48S PICs makes the rp uS3 inaccessible for binding of RNAs and this factor subunit is responsible for the decrease of h16 conformational flexibility; the latter is manifested as reduced accessibility of h16 to BzCN. Thus, our findings provide new insights into how eIF3j is implicated in ensuring the proper conformation of the mRNA entry channel, thereby facilitating mRNA loading. PMID:27346718

  16. 42 CFR 423.2120 - Filing briefs with the MAC.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 3 2011-10-01 2011-10-01 false Filing briefs with the MAC. 423.2120 Section 423..., and Judicial Review § 423.2120 Filing briefs with the MAC. Upon request, the MAC will give the enrollee requesting review a reasonable opportunity to file a brief or other written statement about...

  17. Making Connections--The MeneMAC Online Learning Community

    ERIC Educational Resources Information Center

    Sueoka, Lynne

    2005-01-01

    In 2001, the MeneMAC (Media Arts Communications, dubbed "MeneMAC" in honor of the school mascot, the menehune) Learning Center at Moanalua High School (MoHS), inaugurated its integrated media curriculum for its class of 27 entering freshmen. MeneMAC originated as a media learning center, offering students a chance to explore their interests and…

  18. Energy-efficient MAC Protocol for Patient Personal Area Networks.

    PubMed

    Lamprinos, I; Prentza, A; Sakka, E; Koutsouris, D

    2005-01-01

    The formulation of a Personal Area Network (PAN), consisting of a wireless infrastructure of medical sensors, attached to patient's body, and a supervising device carried by them, lays the path for continuous and real-time monitoring of vital signs without discomforting the person in question. This infrastructure enhances the context of remote healthcare services by supporting flexible acquisition of crucial vital signs, while at the same time it provides more convenience to the patient. Aiming at the exploitation of the inherent features and requirements of wireless medical sensor networks, in this paper we focus on the main design guidelines of a low power Medium Access Control (MAC) protocol, designated to support a patient PAN. The proposed protocol intends to improve energy efficiency in such applications and thus is oriented towards the prevention of main energy wastage sources, such as collision, idle listening and power outspending. PMID:17281057

  19. Strategies for Optimal MAC Parameters Tuning in IEEE 802.15.6 Wearable Wireless Sensor Networks.

    PubMed

    Alam, Muhammad Mahtab; Ben Hamida, Elyes

    2015-09-01

    Wireless body area networks (WBAN) has penetrated immensely in revolutionizing the classical heath-care system. Recently, number of WBAN applications has emerged which introduce potential limits to existing solutions. In particular, IEEE 802.15.6 standard has provided great flexibility, provisions and capabilities to deal emerging applications. In this paper, we investigate the application-specific throughput analysis by fine-tuning the physical (PHY) and medium access control (MAC) parameters of the IEEE 802.15.6 standard. Based on PHY characterizations in narrow band, at the MAC layer, carrier sense multiple access collision avoidance (CSMA/CA) and scheduled access protocols are extensively analyzed. It is concluded that, IEEE 802.15.6 standard can satisfy most of the WBANs applications throughput requirements by maximum achieving 680 Kbps. However, those emerging applications which require high quality audio or video transmissions, standard is not able to meet their constraints. Moreover, delay, energy efficiency and successful packet reception are considered as key performance metrics for comparing the MAC protocols. CSMA/CA protocol provides the best results to meet the delay constraints of medical and non-medical WBAN applications. Whereas, the scheduled access approach, performs very well both in energy efficiency and packet reception ratio. PMID:26266628

  20. An Investigation of How the Channel of Input and Access to Test Questions Affect L2 Listening Test Performance

    ERIC Educational Resources Information Center

    Wagner, Elvis

    2013-01-01

    The use of video technology has become widespread in the teaching and testing of second-language (L2) listening, yet research into how this technology affects the learning and testing process has lagged. The current study investigated how the channel of input (audiovisual vs. audio-only) used on an L2 listening test affected test-taker…

  1. MAC, material accounting database user guide

    SciTech Connect

    Russell, V.K.

    1994-09-22

    The K Basins Material Accounting (MAC) database system user guide describes the user features and functions, and the document is structured like the database menus. This document presents the MAC database system user instructions which explain how to record the movements and configuration of canisters and materials within the K Basins on the computer, the mechanics of handling encapsulation tracking, and administrative functions associated with the system. This document includes the user instructions, which also serve as the software requirements specification for the system implemented on the microcomputer. This includes suggested user keystrokes, examples of screens displayed by the system, and reports generated by the system. It shows how the system is organized, via menus and screens. It does not explain system design nor provide programmer instructions.

  2. IUPHAR-DB: An Open-Access, Expert-Curated Resource for Receptor and Ion Channel Research

    PubMed Central

    2011-01-01

    This contribution highlights efforts by the International Union of Basic and Clinical Pharmacology (IUPHAR) Nomenclature Committee (NC-IUPHAR) to classify human receptors and ion channels, to document their properties, and to recommend ligands that are useful for characterization. This effort has inspired the creation of an online database (IUPHAR-DB), which is intended to provide free information to all scientists, summarized from primary literature by experts. PMID:22778867

  3. MAC protocol for ad hoc networks using a genetic algorithm.

    PubMed

    Elizarraras, Omar; Panduro, Marco; Méndez, Aldo L; Reyna, Alberto

    2014-01-01

    The problem of obtaining the transmission rate in an ad hoc network consists in adjusting the power of each node to ensure the signal to interference ratio (SIR) and the energy required to transmit from one node to another is obtained at the same time. Therefore, an optimal transmission rate for each node in a medium access control (MAC) protocol based on CSMA-CDMA (carrier sense multiple access-code division multiple access) for ad hoc networks can be obtained using evolutionary optimization. This work proposes a genetic algorithm for the transmission rate election considering a perfect power control, and our proposition achieves improvement of 10% compared with the scheme that handles the handshaking phase to adjust the transmission rate. Furthermore, this paper proposes a genetic algorithm that solves the problem of power combining, interference, data rate, and energy ensuring the signal to interference ratio in an ad hoc network. The result of the proposed genetic algorithm has a better performance (15%) compared to the CSMA-CDMA protocol without optimizing. Therefore, we show by simulation the effectiveness of the proposed protocol in terms of the throughput. PMID:25140339

  4. MAC Protocol for Ad Hoc Networks Using a Genetic Algorithm

    PubMed Central

    Elizarraras, Omar; Panduro, Marco; Méndez, Aldo L.

    2014-01-01

    The problem of obtaining the transmission rate in an ad hoc network consists in adjusting the power of each node to ensure the signal to interference ratio (SIR) and the energy required to transmit from one node to another is obtained at the same time. Therefore, an optimal transmission rate for each node in a medium access control (MAC) protocol based on CSMA-CDMA (carrier sense multiple access-code division multiple access) for ad hoc networks can be obtained using evolutionary optimization. This work proposes a genetic algorithm for the transmission rate election considering a perfect power control, and our proposition achieves improvement of 10% compared with the scheme that handles the handshaking phase to adjust the transmission rate. Furthermore, this paper proposes a genetic algorithm that solves the problem of power combining, interference, data rate, and energy ensuring the signal to interference ratio in an ad hoc network. The result of the proposed genetic algorithm has a better performance (15%) compared to the CSMA-CDMA protocol without optimizing. Therefore, we show by simulation the effectiveness of the proposed protocol in terms of the throughput. PMID:25140339

  5. Paired lunar meteorites MAC88104 and MAC88105: A new FAN of lunar petrology

    SciTech Connect

    Neal, C.R. Univ. of Notre Dame, IN ); Taylor, L.A. ); Lui, Yungang; Schmitt, R.A. )

    1991-11-01

    New lunar meteorite MAC88104/5 represents an exciting new opportunity to study a potentially unsampled region of the Moon. The authors have analyzed six thin sections by electron microprobe and three bulk samples by Instrumental Neutron Activation (INA) in order to determine the chemical characteristics of this new lunar sample. Lunar meteorite MAC88104/5 is dominated by lithologies of the ferroan anorthosite (FAN) suite and contains abundant granulitized highland clasts, devitrified glass beads of impact origin, and two small clasts which appear to be of basaltic origin. One of these basaltic clasts (clast E in MAC88105,84) is probably mesostasis material, whereas the second larger clast (clast G) may be similar to the Very Low-Ti (VLT) or low-Ti/high-alumina mare basalts. Impact melt clasts MAC88105,69 and ,72 have major and trace element compositions similar to the bulk meteorite. There is little evidence of any LKFM (Low-K Fra Mauro or low-K KREEP) contribution to this meteorite, as MAC88104/5 and other brecciated lunar meteorites are Fe-rich and poor in the incompatible elements relative to Apollo 16 regolith and feldspathic breccias. While the exact site of origin for the lunar meteorites cannot be pinpointed, it is evident that they were divided from a relatively KREEP-free ferroan anorthosite terrain.

  6. Centralized Routing and Scheduling Using Multi-Channel System Single Transceiver in 802.16d

    NASA Astrophysics Data System (ADS)

    Al-Hemyari, A.; Noordin, N. K.; Ng, Chee Kyun; Ismail, A.; Khatun, S.

    This paper proposes a cross-layer optimized strategy that reduces the effect of interferences from neighboring nodes within a mesh networks. This cross-layer design relies on the routing information in network layer and the scheduling table in medium access control (MAC) layer. A proposed routing algorithm in network layer is exploited to find the best route for all subscriber stations (SS). Also, a proposed centralized scheduling algorithm in MAC layer is exploited to assign a time slot for each possible node transmission. The cross-layer optimized strategy is using multi-channel single transceiver and single channel single transceiver systems for WiMAX mesh networks (WMNs). Each node in WMN has a transceiver that can be tuned to any available channel for eliminating the secondary interference. Among the considered parameters in the performance analysis are interference from the neighboring nodes, hop count to the base station (BS), number of children per node, slot reuse, load balancing, quality of services (QoS), and node identifier (ID). Results show that the proposed algorithms significantly improve the system performance in terms of length of scheduling, channel utilization ratio (CUR), system throughput, and average end to end transmission delay.

  7. 1-Tb/s single-channel coherent optical OFDM transmission over 600-km SSMF fiber with subwavelength bandwidth access.

    PubMed

    Ma, Yiran; Yang, Qi; Tang, Yan; Chen, Simin; Shieh, William

    2009-05-25

    A 1-Tb/s single-channel coherent optical OFDM (CO-OFDM) signal consisting of continuous 4,104 spectrally-overlapped subcarriers is generated using a novel device of recirculating frequency shifter (RFS). The RFS produces 320.6-GHz wide spectrum using a single laser with superior flatness and tone-to-noise ratio (TNR). The 1-Tb/s CO-OFDM signal is comprised of 36 uncorrelated orthogonal bands achieved by adjusting the delay of the RFS to an integer number of OFDM symbol periods. The 1- Tb/s CO-OFDM signal with a spectral efficiency of 3.3 bit/s/Hz is successfully received after transmission over 600-km SSMF fiber without either Raman amplification or dispersion compensation. PMID:19466194

  8. Four-Channel, 8 x 8 Bit, Two-Dimensional Parallel Transmission by use of Space-Code-Division Multiple-Access Encoder and Decoder Modules.

    PubMed

    Nakamura, M; Kitayama, K; Igasaki, Y; Kaneda, K

    1998-07-10

    We experimentally demonstrate four-channel multiplexing of 64-bit (8 x 8) two-dimensional (2-D) parallel data links on the basis of optical space-code-division multiple access (CDMA) by using new modules of optical spatial encoders and a decoder with a new high-contrast 9-m-long image fiber with 3 x 10(4) cores. Each 8 x 8 bit plane (64-bit parallel data) is optically encoded with an 8 x 8, 2-D optical orthogonal signature pattern. The encoded bit planes are spatially multiplexed and transmitted through an image fiber. A receiver can recover the intended input bit plane by means of an optical decoding process. This result should encourage the application of optical space-CDMA to future high-throughput 2-D parallel data links connecting massively parallel processors. PMID:18285889

  9. A very low power MAC (VLPM) protocol for Wireless Body Area Networks.

    PubMed

    Ullah, Niamat; Khan, Pervez; Kwak, Kyung Sup

    2011-01-01

    Wireless Body Area Networks (WBANs) consist of a limited number of battery operated nodes that are used to monitor the vital signs of a patient over long periods of time without restricting the patient's movements. They are an easy and fast way to diagnose the patient's status and to consult the doctor. Device as well as network lifetime are among the most important factors in a WBAN. Prolonging the lifetime of the WBAN strongly depends on controlling the energy consumption of sensor nodes. To achieve energy efficiency, low duty cycle MAC protocols are used, but for medical applications, especially in the case of pacemakers where data have time-limited relevance, these protocols increase latency which is highly undesirable and leads to system instability. In this paper, we propose a low power MAC protocol (VLPM) based on existing wakeup radio approaches which reduce energy consumption as well as improving the response time of a node. We categorize the traffic into uplink and downlink traffic. The nodes are equipped with both a low power wake-up transmitter and receiver. The low power wake-up receiver monitors the activity on channel all the time with a very low power and keeps the MCU (Micro Controller Unit) along with main radio in sleep mode. When a node [BN or BNC (BAN Coordinator)] wants to communicate with another node, it uses the low-power radio to send a wakeup packet, which will prompt the receiver to power up its primary radio to listen for the message that follows shortly. The wake-up packet contains the desired node's ID along with some other information to let the targeted node to wake-up and take part in communication and let all other nodes to go to sleep mode quickly. The VLPM protocol is proposed for applications having low traffic conditions. For high traffic rates, optimization is needed. Analytical results show that the proposed protocol outperforms both synchronized and unsynchronized MAC protocols like T-MAC, SCP-MAC, B-MAC and X-MAC in terms

  10. A Very Low Power MAC (VLPM) Protocol for Wireless Body Area Networks

    PubMed Central

    Ullah, Niamat; Khan, Pervez; Kwak, Kyung Sup

    2011-01-01

    Wireless Body Area Networks (WBANs) consist of a limited number of battery operated nodes that are used to monitor the vital signs of a patient over long periods of time without restricting the patient’s movements. They are an easy and fast way to diagnose the patient’s status and to consult the doctor. Device as well as network lifetime are among the most important factors in a WBAN. Prolonging the lifetime of the WBAN strongly depends on controlling the energy consumption of sensor nodes. To achieve energy efficiency, low duty cycle MAC protocols are used, but for medical applications, especially in the case of pacemakers where data have time-limited relevance, these protocols increase latency which is highly undesirable and leads to system instability. In this paper, we propose a low power MAC protocol (VLPM) based on existing wakeup radio approaches which reduce energy consumption as well as improving the response time of a node. We categorize the traffic into uplink and downlink traffic. The nodes are equipped with both a low power wake-up transmitter and receiver. The low power wake-up receiver monitors the activity on channel all the time with a very low power and keeps the MCU (Micro Controller Unit) along with main radio in sleep mode. When a node [BN or BNC (BAN Coordinator)] wants to communicate with another node, it uses the low-power radio to send a wakeup packet, which will prompt the receiver to power up its primary radio to listen for the message that follows shortly. The wake-up packet contains the desired node’s ID along with some other information to let the targeted node to wake-up and take part in communication and let all other nodes to go to sleep mode quickly. The VLPM protocol is proposed for applications having low traffic conditions. For high traffic rates, optimization is needed. Analytical results show that the proposed protocol outperforms both synchronized and unsynchronized MAC protocols like T-MAC, SCP-MAC, B-MAC and X-MAC in

  11. Introduction to MacDraft. High-Technology Training Module.

    ERIC Educational Resources Information Center

    Traxler, Gene

    This training module on MacDraft is part of a computer drafting skills unit on communications technology for grades 9-12. The objective is for each student to complete a drawing on the MacIntosh computer using the MacDraft software program. This drawing is to be dimensioned with a dual system and is to include a border and title block. This module…

  12. Wireless Sensor Networks Energy-Efficient MAC Protocol

    NASA Astrophysics Data System (ADS)

    Lijuan, Du; Yuanpeng, Wang; WeiPeng, Jing

    This paper presents a new wireless sensor network energy-efficient MAC protocol, ES-MAC protocol, and shows the results of simulation experiments. During the transmission the nodes do not send ACK packages while use a small amount of new information packets, so they can reduce unnecessary energy loss and wasted time. The theoretical analysis and simulation results show that ES-MAC protocol reduces energy consumption while reducing network latency and improving network throughput.

  13. A Mobile Automated Characterization System (MACS) for indoor floor characterization

    SciTech Connect

    Richardson, B.S.; Haley, D.C.; Dudar, A.M.; Ward, C.R.

    1995-03-01

    The Savannah River Technology Center (SRTC) and Oak Ridge National Laboratory are developing an advanced Mobile Automated Characterization System (MACS) to characterize indoor contaminated floors. MACS is based upon Semi-Intelligent Mobile Observing Navigator (SIMON), an earlier floor characterization system developed at SRTC. MACS will feature enhanced navigation systems, operator interface, and an interface to simplify integration of additional sensors. The enhanced navigation system will provide the capability to survey large open areas much more accurately than is now possible with SIMON, which is better suited for hallways and corridors that provide the means for recalibrating position and heading. MACS operator interface is designed to facilitate MACS`s use as a tool for health physicists, thus eliminating the need for additional training in the robot`s control language. Initial implementation of MACS will use radiation detectors. Additional sensors, such as PCB sensors currently being developed, will be integrated on MACS in the future. Initial use of MACS will be focused toward obtaining comparative results with manual methods. Surveys will be conducted both manually and with MACS to compare relative costs and data quality. While clear cost benefits anticipated, data quality benefits should be even more significant.

  14. ATLAS: A Traffic Load Aware Sensor MAC Design for Collaborative Body Area Sensor Networks

    PubMed Central

    Rahman, Md. Obaidur; Hong, Choong Seon; Lee, Sungwon; Bang, Young-Cheol

    2011-01-01

    In collaborative body sensor networks, namely wireless body area networks (WBANs), each of the physical sensor applications is used to collaboratively monitor the health status of the human body. The applications of WBANs comprise diverse and dynamic traffic loads such as very low-rate periodic monitoring (i.e., observation) data and high-rate traffic including event-triggered bursts. Therefore, in designing a medium access control (MAC) protocol for WBANs, energy conservation should be the primary concern during low-traffic periods, whereas a balance between satisfying high-throughput demand and efficient energy usage is necessary during high-traffic times. In this paper, we design a traffic load-aware innovative MAC solution for WBANs, called ATLAS. The design exploits the superframe structure of the IEEE 802.15.4 standard, and it adaptively uses the contention access period (CAP), contention free period (CFP) and inactive period (IP) of the superframe based on estimated traffic load, by applying a dynamic “wh” (whenever which is required) approach. Unlike earlier work, the proposed MAC design includes load estimation for network load-status awareness and a multi-hop communication pattern in order to prevent energy loss associated with long range transmission. Finally, ATLAS is evaluated through extensive simulations in ns-2 and the results demonstrate the effectiveness of the protocol. PMID:22247681

  15. ATLAS: a traffic load aware sensor MAC design for collaborative body area sensor networks.

    PubMed

    Rahman, Md Obaidur; Hong, Choong Seon; Lee, Sungwon; Bang, Young-Cheol

    2011-01-01

    In collaborative body sensor networks, namely wireless body area networks (WBANs), each of the physical sensor applications is used to collaboratively monitor the health status of the human body. The applications of WBANs comprise diverse and dynamic traffic loads such as very low-rate periodic monitoring (i.e., observation) data and high-rate traffic including event-triggered bursts. Therefore, in designing a medium access control (MAC) protocol for WBANs, energy conservation should be the primary concern during low-traffic periods, whereas a balance between satisfying high-throughput demand and efficient energy usage is necessary during high-traffic times. In this paper, we design a traffic load-aware innovative MAC solution for WBANs, called ATLAS. The design exploits the superframe structure of the IEEE 802.15.4 standard, and it adaptively uses the contention access period (CAP), contention free period (CFP) and inactive period (IP) of the superframe based on estimated traffic load, by applying a dynamic "wh" (whenever which is required) approach. Unlike earlier work, the proposed MAC design includes load estimation for network load-status awareness and a multi-hop communication pattern in order to prevent energy loss associated with long range transmission. Finally, ATLAS is evaluated through extensive simulations in ns-2 and the results demonstrate the effectiveness of the protocol. PMID:22247681

  16. Detection of Spoofed MAC Addresses in 802.11 Wireless Networks

    NASA Astrophysics Data System (ADS)

    Tao, Kai; Li, Jing; Sampalli, Srinivas

    Medium Access Control (MAC) address spoofing is considered as an important first step in a hacker's attempt to launch a variety of attacks on 802.11 wireless networks. Unfortunately, MAC address spoofing is hard to detect. Most current spoofing detection systems mainly use the sequence number (SN) tracking technique, which has drawbacks. Firstly, it may lead to an increase in the number of false positives. Secondly, such techniques cannot be used in systems with wireless cards that do not follow standard 802.11 sequence number patterns. Thirdly, attackers can forge sequence numbers, thereby causing the attacks to go undetected. We present a new architecture called WISE GUARD (Wireless Security Guard) for detection of MAC address spoofing on 802.11 wireless LANs. It integrates three detection techniques - SN tracking, Operating System (OS) fingerprinting & tracking and Received Signal Strength (RSS) fingerprinting & tracking. It also includes the fingerprinting of Access Point (AP) parameters as an extension to the OS fingerprinting for detection of AP address spoofing. We have implemented WISE GUARD on a test bed using off-the-shelf wireless devices and open source drivers. Experimental results show that the new design enhances the detection effectiveness and reduces the number of false positives in comparison with current approaches.

  17. A Novel Energy-Efficient MAC Aware Data Aggregation Routing in Wireless Sensor Networks.

    PubMed

    Lin, Frank Yeong-Sung; Yen, Hong-Hsu; Lin, Shu-Ping

    2009-01-01

    Embedding data-aggregation capabilities into sensor nodes of wireless networks could save energy by reducing redundant data flow transmissions. Existing research describes the construction of data aggregation trees to maximize data aggregation times in order to reduce data transmission of redundant data. However, aggregation of more nodes on the same node will incur significant collisions. These MAC (Media Access Control) layer collisions introduce additional data retransmissions that could jeopardize the advantages of data aggregation. This paper is the first to consider the energy consumption tradeoffs between data aggregation and retransmissions in a wireless sensor network. By using the existing CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) MAC protocol, the retransmission energy consumption function is well formulated. This paper proposes a novel non-linear mathematical formulation, whose function is to minimize the total energy consumption of data transmission subject to data aggregation trees and data retransmissions. This solution approach is based on Lagrangean relaxation, in conjunction with optimization-based heuristics. From the computational experiments, it is shown that the proposed algorithms could construct MAC aware data aggregation trees that are up to 59% more energy efficient than existing data aggregation algorithms. PMID:22573969

  18. TreeMAC: Localized TDMA MAC protocol for real-time high-data-rate sensor networks

    USGS Publications Warehouse

    Song, W.-Z.; Huang, R.; Shirazi, B.; LaHusen, R.

    2009-01-01

    Earlier sensor network MAC protocols focus on energy conservation in low-duty cycle applications, while some recent applications involve real-time high-data-rate signals. This motivates us to design an innovative localized TDMA MAC protocol to achieve high throughput and low congestion in data collection sensor networks, besides energy conservation. TreeMAC divides a time cycle into frames and each frame into slots. A parent node determines the children's frame assignment based on their relative bandwidth demand, and each node calculates its own slot assignment based on its hop-count to the sink. This innovative 2-dimensional frame-slot assignment algorithm has the following nice theory properties. First, given any node, at any time slot, there is at most one active sender in its neighborhood (including itself). Second, the packet scheduling with TreeMAC is bufferless, which therefore minimizes the probability of network congestion. Third, the data throughput to the gateway is at least 1/3 of the optimum assuming reliable links. Our experiments on a 24-node testbed show that TreeMAC protocol significantly improves network throughput, fairness, and energy efficiency compared to TinyOS's default CSMA MAC protocol and a recent TDMA MAC protocol Funneling-MAC. Partial results of this paper were published in Song, Huang, Shirazi and Lahusen [W.-Z. Song, R. Huang, B. Shirazi, and R. Lahusen, TreeMAC: Localized TDMA MAC protocol for high-throughput and fairness in sensor networks, in: The 7th Annual IEEE International Conference on Pervasive Computing and Communications, PerCom, March 2009]. Our new contributions include analyses of the performance of TreeMAC from various aspects. We also present more implementation detail and evaluate TreeMAC from other aspects. ?? 2009 Elsevier B.V.

  19. A comprehensive survey of Wireless Body Area Networks : on PHY, MAC, and Network layers solutions.

    PubMed

    Ullah, Sana; Higgins, Henry; Braem, Bart; Latre, Benoit; Blondia, Chris; Moerman, Ingrid; Saleem, Shahnaz; Rahman, Ziaur; Kwak, Kyung Sup

    2012-06-01

    Recent advances in microelectronics and integrated circuits, system-on-chip design, wireless communication and intelligent low-power sensors have allowed the realization of a Wireless Body Area Network (WBAN). A WBAN is a collection of low-power, miniaturized, invasive/non-invasive lightweight wireless sensor nodes that monitor the human body functions and the surrounding environment. In addition, it supports a number of innovative and interesting applications such as ubiquitous healthcare, entertainment, interactive gaming, and military applications. In this paper, the fundamental mechanisms of WBAN including architecture and topology, wireless implant communication, low-power Medium Access Control (MAC) and routing protocols are reviewed. A comprehensive study of the proposed technologies for WBAN at Physical (PHY), MAC, and Network layers is presented and many useful solutions are discussed for each layer. Finally, numerous WBAN applications are highlighted. PMID:20721685

  20. C-Band Airport Surface Communications System Standards Development. Phase II Final Report. Volume 2: Test Bed Performance Evaluation and Final AeroMACS Recommendations

    NASA Technical Reports Server (NTRS)

    Hall, Edward; Magner, James

    2011-01-01

    This report is provided as part of ITT s NASA Glenn Research Center Aerospace Communication Systems Technical Support (ACSTS) contract NNC05CA85C, Task 7: New ATM Requirements-Future Communications, C-Band and L-Band Communications Standard Development and was based on direction provided by FAA project-level agreements for New ATM Requirements-Future Communications. Task 7 included two subtasks. Subtask 7-1 addressed C-band (5091- to 5150-MHz) airport surface data communications standards development, systems engineering, test bed and prototype development, and tests and demonstrations to establish operational capability for the Aeronautical Mobile Airport Communications System (AeroMACS). Subtask 7-2 focused on systems engineering and development support of the L-band digital aeronautical communications system (L-DACS). Subtask 7-1 consisted of two phases. Phase I included development of AeroMACS concepts of use, requirements, architecture, and initial high-level safety risk assessment. Phase II builds on Phase I results and is presented in two volumes. Volume I is devoted to concepts of use, system requirements, and architecture, including AeroMACS design considerations. Volume II (this document) describes an AeroMACS prototype evaluation and presents final AeroMACS recommendations. This report also describes airport categorization and channelization methodologies. The purposes of the airport categorization task were (1) to facilitate initial AeroMACS architecture designs and enable budgetary projections by creating a set of airport categories based on common airport characteristics and design objectives, and (2) to offer high-level guidance to potential AeroMACS technology and policy development sponsors and service providers. A channelization plan methodology was developed because a common global methodology is needed to assure seamless interoperability among diverse AeroMACS services potentially supplied by multiple service providers.

  1. C-Band Airport Surface Communications System Standards Development. Phase II Final Report. Volume 1: Concepts of Use, Initial System Requirements, Architecture, and AeroMACS Design Considerations

    NASA Technical Reports Server (NTRS)

    Hall, Edward; Isaacs, James; Henriksen, Steve; Zelkin, Natalie

    2011-01-01

    This report is provided as part of ITT s NASA Glenn Research Center Aerospace Communication Systems Technical Support (ACSTS) contract NNC05CA85C, Task 7: New ATM Requirements-Future Communications, C-Band and L-Band Communications Standard Development and was based on direction provided by FAA project-level agreements for New ATM Requirements-Future Communications. Task 7 included two subtasks. Subtask 7-1 addressed C-band (5091- to 5150-MHz) airport surface data communications standards development, systems engineering, test bed and prototype development, and tests and demonstrations to establish operational capability for the Aeronautical Mobile Airport Communications System (AeroMACS). Subtask 7-2 focused on systems engineering and development support of the L-band digital aeronautical communications system (L-DACS). Subtask 7-1 consisted of two phases. Phase I included development of AeroMACS concepts of use, requirements, architecture, and initial high-level safety risk assessment. Phase II builds on Phase I results and is presented in two volumes. Volume I (this document) is devoted to concepts of use, system requirements, and architecture, including AeroMACS design considerations. Volume II describes an AeroMACS prototype evaluation and presents final AeroMACS recommendations. This report also describes airport categorization and channelization methodologies. The purposes of the airport categorization task were (1) to facilitate initial AeroMACS architecture designs and enable budgetary projections by creating a set of airport categories based on common airport characteristics and design objectives, and (2) to offer high-level guidance to potential AeroMACS technology and policy development sponsors and service providers. A channelization plan methodology was developed because a common global methodology is needed to assure seamless interoperability among diverse AeroMACS services potentially supplied by multiple service providers.

  2. SuperMacLang: Development of an Authoring System.

    ERIC Educational Resources Information Center

    Frommer, Judith; Foelsche, Otmar K. E.

    1999-01-01

    Describes the development of "SuperMacLang, the 1990s version of the MacLang authoring system. An analysis of various features of the program explains the ways in which certain aspects of collaboration and funding affected developer and programming decisions. (Author/VWL)

  3. Steven MacCall: Winner of LJ's 2010 Teaching Award

    ERIC Educational Resources Information Center

    Berry, John N., III

    2010-01-01

    This article profiles Steven L. MacCall, winner of "Library Journal's" 2010 Teaching Award. An associate professor at the School of Library and Information Studies (SLIS) at the University of Alabama, Tuscaloosa, MacCall was nominated by Kathie Popadin, known as "Kpop" to the members of her cohort in the online MLIS program at SLIS. Sixteen of…

  4. REGIONAL ASSESSMENT OF EXPOSURE TO MYCOBACTERIUM AVIUM COMPLEX(MAC)

    EPA Science Inventory

    There is accumulating evidence that potable water is a source of Mycobacterium avium complex (MAC). The linkage of mycobacteriosis to drinking water has been shown in AIDS populations where up to 8% of deaths in this group is attributed to MAC. Infection with these organisms ha...

  5. Intel-Based Mac Computers Improve Teaching and Learning

    ERIC Educational Resources Information Center

    Technology & Learning, 2007

    2007-01-01

    Today, Mac computers offer schools an easy and powerful way to engage students in learning, foster 21st century skills and leverage existing software assets. Innovative software and hardware built into the Mac allows students to demonstrate their individual strengths--empowering them to be creators of content, rather than just consumers. Judging…

  6. GENETIC FINGERPRINTING OF MYCOBACTERIUM AVIUM COMPLEX (MAC) ORGANISMS ISOLATED FROM HOSPITAL PATIENTS AND THE ENVIRONMENT

    EPA Science Inventory

    A particularly pathogenic group of mycobacteria belong to the Mycobacterium avium complex (MAC), which includes M. avium and M. intracellulare. MAC organisms cause disease in children, the elderly, and immuno-compromised individuals. A critical step in preventing MAC infections...

  7. Middle Atmosphere Cooperation/Summer in Northern Europe (MAC/SINE) and MAC/Epsilon

    NASA Technical Reports Server (NTRS)

    Thrane, E. V.

    1989-01-01

    Two major international campaigns dedicated to the study of middle atmosphere dynamics in high latitudes were successfully completed in 1987. MAC/SINE (Middle Atmosphere Cooperation/Summer in Northern Europe) was carried out during the period 7 June to 19 July, whereas MAC/Epsilon took place in the period 12 October to 15 November. In both campaigns a large number of ground based and rocket techniques were used in a concerted effort to map the dynamical structure of the middle atmosphere over Northern Europe. Although the analysis of the observations has only just started, it is clear that a large and unique data set was obtained, which is believed will provide new insight into the dynamical processes in this interesting region of the atmosphere. A brief overview of the campaigns, their scientific aims, organization and structure is presented.

  8. [Monitoring Required for Monitored Anesthesia Care (MAC) and Specific MAC Methodologies].

    PubMed

    Suzuki, Toshiyasu

    2015-03-01

    Many physicians responsible for monitored anesthesia care (MAC) are not anesthesiologists and are not acquainted with treatment in response to sudden changes in patient condition. In particular, rapid response and early detection are essential for respiratory depression. Physicians engaged in MAC require pharmacological knowledge regarding sedative and analgesic medications, need to be able to accurately evaluate physiological responses to sedative and anesthetic levels, and need to be acquainted with emergency procedures such as basic life support (BLS) and advanced cardiovascular life support (ACLS). Patient management focusing on both ventilation and oxygenation, through the use of capnography and continuous respiratory monitoring, in addition to oxygenation monitoring using a pulse oximeter, and measuring ECGs and blood pressure in the management of sedated patients, is also important. PMID:26121782

  9. Paired lunar meteorites MAC88104 and MAC88105 - A new 'FAN' of lunar petrology. [ferroan anorthosite

    NASA Technical Reports Server (NTRS)

    Neal, Clive R.; Taylor, Lawrence A.; Lui, Yun-Gang; Schmitt, Roman A.

    1991-01-01

    To determine the chemical characteristics of the MAC88104/5 meteorite six thin sections and three bulk samples were analyzed by electron microprobe and instrumental neutron activation. It is concluded that this meteorite is dominated by lithologies of the ferroan anorthosite suite and contains abundant granulitized highland clasts, devitrified glass beads of impact origin, and two small clasts of basaltic origin. It is suggested that one of these basaltic clasts, clast E, is mesostasis material, and clast G is similar to the very low-Ti or low-Ti/high-alumina mare basalts. Impact melt clasts MAC88105, 69, and 72 have major and trace element compositions similar to the bulk meteorite.

  10. A ferroan region of the lunar highlands as recorded in meteorites MAC88104 and MAC88105

    SciTech Connect

    Jolliff, B.L.; Korotev, R.L.; Haskin, L.A. )

    1991-11-01

    MacAlpine Hills 88104 and 88105 (MAC88104/5) are paired meteorites of noritic anorthosite composition from the lunar highlands. MAC88105 is a breccia composed mainly of melt-breccia clasts in a fine-grained, fragmental, and partly glassy matrix. The most abundant melt lithologies are feldspathic and are similar in composition to the bulk meteorite. Other melt lithologies include feldspathic melt rocks, mafic melt breccias, and a rare melt breccia relatively enriched in incompatible trace elements. Subordinate lithic clasts are granulitic breccias and ferroan (relatively low Mg/(Mg + Fe)) igneous lithologies, including troctolitic anorthosite, anorthositic norite, gabbronorite, and anorthosite. Igneous clasts having mafic mineral compositions more magnesian than Fo{sub 55} and En{sub 60} were not observed. Rare fragments of glass spheres and shards as well as glass clasts indicate that the meteorite was derived from an immature regolith. The bulk composition of MAC88105 is characterized by a molar Mg/(Mg + Fe) ratio of 0.62, at the extreme low end of the range for meteorites from the lunar highlands. Its low concentrations of incompatible trace elements and feldspathic bulk composition (29% Al{sub 2}O{sub 3}), suggests that it, like the other lunar meteorites, formed at a site far removed from the areas sampled by the Apollo missions. Similarities in mineral compositions among the different lithologies of the breccia and the distribution of mineral fragments suggest that most components of the meteorite were derived from a crustal section dominated by material with a noritic anorthosite composition and an affinity of the ferroan suite of plutonic rocks.

  11. TreeMAC: Localized TDMA MAC protocol for real-time high-data-rate sensor networks

    USGS Publications Warehouse

    Song, W.-Z.; Huang, R.; Shirazi, B.; Husent, R.L.

    2009-01-01

    Earlier sensor network MAC protocols focus on energy conservation in low-duty cycle applications, while some recent applications involve real-time high-data-rate signals. This motivates us to design an innovative localized TDMA MAC protocol to achieve high throughput and low congestion in data collection sensor networks, besides energy conservation. TreeMAC divides a time cycle into frames and frame into slots. Parent determines children's frame assigmnent based on their relative bandwidth demand, and each node calculates its own slot assignment based on its hop-count to the sink. This innovative 2-dimensional frame-slot assignment algorithm has the following nice theory properties. Firstly, given any node, at any time slot, there is at most one active sender in its neighborhood (includ ing itself). Secondly, the packet scheduling with TreelMAC is bufferless, which therefore minimizes the probability of network congestion. Thirdly, the data throughput to gateway is at least 1/3 of the optimum assuming reliable links. Our experiments on a 24 node test bed demonstrate that TreeMAC protocol significantly improves network throughput and energy efficiency, by comparing to the TinyOS's default CSMA MAC protocol and a recent TDMA MAC protocol Funneling-MAC[8]. ?? 2009 IEEE.

  12. A MAC Protocol to Support Monitoring of Underwater Spaces.

    PubMed

    Santos, Rodrigo; Orozco, Javier; Ochoa, Sergio F; Meseguer, Roc; Eggly, Gabriel; Pistonesi, Marcelo F

    2016-01-01

    Underwater sensor networks are becoming an important field of research, because of their everyday increasing application scope. Examples of their application areas are environmental and pollution monitoring (mainly oil spills), oceanographic data collection, support for submarine geolocalization, ocean sampling and early tsunamis alert. The challenge of performing underwater communications is well known, provided that radio signals are useless in this medium, and a wired solution is too expensive. Therefore, the sensors in these networks transmit their information using acoustic signals that propagate well under water. This data transmission type not only brings an opportunity, but also several challenges to the implementation of these networks, e.g., in terms of energy consumption, data transmission and signal interference. In order to help advance the knowledge in the design and implementation of these networks for monitoring underwater spaces, this paper proposes a MAC protocol for acoustic communications between the nodes, based on a self-organized time division multiple access mechanism. The proposal was evaluated using simulations of a real monitoring scenario, and the obtained results are highly encouraging. PMID:27355950

  13. A MAC Protocol to Support Monitoring of Underwater Spaces †

    PubMed Central

    Santos, Rodrigo; Orozco, Javier; Ochoa, Sergio F.; Meseguer, Roc; Eggly, Gabriel; Pistonesi, Marcelo F.

    2016-01-01

    Underwater sensor networks are becoming an important field of research, because of their everyday increasing application scope. Examples of their application areas are environmental and pollution monitoring (mainly oil spills), oceanographic data collection, support for submarine geolocalization, ocean sampling and early tsunamis alert. The challenge of performing underwater communications is well known, provided that radio signals are useless in this medium, and a wired solution is too expensive. Therefore, the sensors in these networks transmit their information using acoustic signals that propagate well under water. This data transmission type not only brings an opportunity, but also several challenges to the implementation of these networks, e.g., in terms of energy consumption, data transmission and signal interference. In order to help advance the knowledge in the design and implementation of these networks for monitoring underwater spaces, this paper proposes a MAC protocol for acoustic communications between the nodes, based on a self-organized time division multiple access mechanism. The proposal was evaluated using simulations of a real monitoring scenario, and the obtained results are highly encouraging. PMID:27355950

  14. Precoding Method Interference Management for Quasi-EVD Channel

    PubMed Central

    Song, Wei; Song, Sang Seob

    2014-01-01

    The Cholesky decomposition-block diagonalization (CD-BD) interference alignment (IA) for a multiuser multiple input multiple output (MU-MIMO) relay system is proposed, which designs precoders for the multiple access channel (MAC) by employing the singular value decomposition (SVD) as well as the mean square error (MSE) detector for the broadcast Hermitian channel (BHC) taken advantage of in our design. Also, in our proposed CD-BD IA algorithm, the relaying function is made use to restructure the quasieigenvalue decomposition (quasi-EVD) equivalent channel. This approach used for the design of BD precoding matrix can significantly reduce the computational complexity and proposed algorithm can address several optimization criteria, which is achieved by designing the precoding matrices in two steps. In the first step, we use Cholesky decomposition to maximize the sum-of-rate (SR) with the minimum mean square error (MMSE) detection. In the next step, we optimize the system BER performance with the overlap of the row spaces spanned by the effective channel matrices of different users. By iterating the closed form of the solution, we are able not only to maximize the achievable sum-of-rate (ASR), but also to minimize the BER performance at a high signal-to-noise ratio (SNR) region. PMID:25258731

  15. Underwater acoustic sensor networks: Medium access control, routing and reliable transfer

    NASA Astrophysics Data System (ADS)

    Xie, Peng

    Recently there have been growing interests in monitoring aquatic environments for scientific exploration, commercial exploitation and coastline protection. The ideal vehicle for this type of extensive monitoring is a mobile underwater sensor network (M-UWSN), consisting of a large number of low cost underwater sensors that can move with water currents and dispersion. M-UWSNs are significantly different from terrestrial sensor networks: (1) Radio channels do not work well under water. They must be replaced by acoustic channels, which feature long propagation delays, low communication bandwidth and high channel error rates; (2) While most ground sensors are static, underwater sensor nodes may move with water currents (and other underwater activities), as introduces passive sensor mobility. Due to the very different environment properties and the unique characteristics of acoustic channels, the protocols developed for terrestrial sensor networks are not applicable to M-UWSNs, and new research at every level of the protocol suite is demanded. In this dissertation work, we investigate three fundamental networking problems in M-UWSN design: medium access control, multi-hop routing and reliable data transfer. (1) Medium access control (MAC): the long propagation delays and narrow communication bandwidth of acoustic channels pose the major challenges to the energy-efficient MAC design in M-UWSNs. For the first time, we formally investigate the random access and RTS/CTS techniques in networks with long propagation delays and low communication bandwidth (as in M-UWSNs). Based on this study, we propose a novel reservation-based MAC approach, called R-MAC, for dense underwater sensor networks with unevenly distributed (spatially and temporally) traffic. Simulation results show that R-MAC is not only energy efficient but also supports fairness. (2) Multi-hop routing: In M-UWSNs, energy efficiency and mobility handling are the two major concerns for multi-hop routing, which have

  16. Code division controlled-MAC in wireless sensor network by adaptive binary signature design

    NASA Astrophysics Data System (ADS)

    Wei, Lili; Batalama, Stella N.; Pados, Dimitris A.; Suter, Bruce

    2007-04-01

    We consider the problem of signature waveform design for code division medium-access-control (MAC) of wireless sensor networks (WSN). In contract to conventional randomly chosen orthogonal codes, an adaptive signature design strategy is developed under the maximum pre-detection SINR (signal to interference plus noise ratio) criterion. The proposed algorithm utilizes slowest descent cords of the optimization surface to move toward the optimum solution and exhibits, upon eigenvector decomposition, linear computational complexity with respect to signature length. Numerical and simulation studies demonstrate the performance of the proposed method and offer comparisons with conventional signature code sets.

  17. Adaptive Code Division Multiple Access Protocol for Wireless Network-on-Chip Architectures

    NASA Astrophysics Data System (ADS)

    Vijayakumaran, Vineeth

    Massive levels of integration following Moore's Law ushered in a paradigm shift in the way on-chip interconnections were designed. With higher and higher number of cores on the same die traditional bus based interconnections are no longer a scalable communication infrastructure. On-chip networks were proposed enabled a scalable plug-and-play mechanism for interconnecting hundreds of cores on the same chip. Wired interconnects between the cores in a traditional Network-on-Chip (NoC) system, becomes a bottleneck with increase in the number of cores thereby increasing the latency and energy to transmit signals over them. Hence, there has been many alternative emerging interconnect technologies proposed, namely, 3D, photonic and multi-band RF interconnects. Although they provide better connectivity, higher speed and higher bandwidth compared to wired interconnects; they also face challenges with heat dissipation and manufacturing difficulties. On-chip wireless interconnects is one other alternative proposed which doesn't need physical interconnection layout as data travels over the wireless medium. They are integrated into a hybrid NOC architecture consisting of both wired and wireless links, which provides higher bandwidth, lower latency, lesser area overhead and reduced energy dissipation in communication. However, as the bandwidth of the wireless channels is limited, an efficient media access control (MAC) scheme is required to enhance the utilization of the available bandwidth. This thesis proposes using a multiple access mechanism such as Code Division Multiple Access (CDMA) to enable multiple transmitter-receiver pairs to send data over the wireless channel simultaneously. It will be shown that such a hybrid wireless NoC with an efficient CDMA based MAC protocol can significantly increase the performance of the system while lowering the energy dissipation in data transfer. In this work it is shown that the wireless NoC with the proposed CDMA based MAC protocol

  18. MAC mini acceptance test procedure, software Version 3.0

    SciTech Connect

    Russell, V.K.

    1994-10-17

    The K Basins Materials Accounting (MAC) programs had some major improvements made to it to organize the main-tables by Location, Canister, and Material. This ATP describes how the code was to be tested to verify its correctness.

  19. 5. Photocopy of drawing of Mac Dougall furnace in roaster ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. Photocopy of drawing of Mac Dougall furnace in roaster building from John L. Bray, The Principles of Metallurgy Ginn & Co., New York, 1929. - International Smelting & Refining Company, Tooele Smelter, Roaster Building, State Route 178, Tooele, Tooele County, UT

  20. MAC layer security issues in wireless mesh networks

    NASA Astrophysics Data System (ADS)

    Reddy, K. Ganesh; Thilagam, P. Santhi

    2016-03-01

    Wireless Mesh Networks (WMNs) have emerged as a promising technology for a broad range of applications due to their self-organizing, self-configuring and self-healing capability, in addition to their low cost and easy maintenance. Securing WMNs is more challenging and complex issue due to their inherent characteristics such as shared wireless medium, multi-hop and inter-network communication, highly dynamic network topology and decentralized architecture. These vulnerable features expose the WMNs to several types of attacks in MAC layer. The existing MAC layer standards and implementations are inadequate to secure these features and fail to provide comprehensive security solutions to protect both backbone and client mesh. Hence, there is a need for developing efficient, scalable and integrated security solutions for WMNs. In this paper, we classify the MAC layer attacks and analyze the existing countermeasures. Based on attacks classification and countermeasures analysis, we derive the research directions to enhance the MAC layer security for WMNs.

  1. Operational effectiveness of a Multiple Aquila Control System (MACS)

    NASA Technical Reports Server (NTRS)

    Brown, R. W.; Flynn, J. D.; Frey, M. R.

    1983-01-01

    The operational effectiveness of a multiple aquila control system (MACS) was examined under a variety of remotely piloted vehicle (RPV) mission configurations. The set of assumptions and inputs used to form the rules under which a computerized simulation of MACS was run is given. The characteristics that are to govern MACS operations include: the battlefield environment that generates the requests for RPV missions, operating time-lines of the RPV-peculiar equipment, maintenance requirements, and vulnerability to enemy fire. The number of RPV missions and the number of operation days are discussed. Command, control, and communication data rates are estimated by determining how many messages are passed and what information is necessary in them to support ground coordination between MACS sections.

  2. A tribute to Lloyd D. MacLean

    PubMed Central

    Keith, Roger G.

    2015-01-01

    Summary Dr. Lloyd D. MacLean, long-time co-editor of the Canadian Journal of Surgery passed away earlier this year at the age of 90. In order to appreciate the contributions of Dr. MacLean to the journal, this commentary recognizes him as a humble surgeon–scientist who was one of — if not the — most outstanding Canadian ambassadors to academic surgery in North America. PMID:26204372

  3. Conformal holonomy in MacDowell-Mansouri gravity

    SciTech Connect

    Reid, James A.; Wang, Charles H.-T.

    2014-03-15

    The MacDowell-Mansouri formulation of general relativity is based on a gauge theory whose gauge algebra depends on the sign of the cosmological constant. In this article, we show that the gauge algebra is uniquely determined by the conformal structure of spacetime itself. Specifically, we show that in vacuum: the spacetime conformal holonomy algebra coincides with the MacDowell-Mansouri gauge algebra for both signs of the cosmological constant, in both Lorentzian and Euclidean metric signatures.

  4. 42 CFR 423.2110 - MAC reviews on its own motion.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 3 2014-10-01 2014-10-01 false MAC reviews on its own motion. 423.2110 Section 423..., MAC review, and Judicial Review § 423.2110 MAC reviews on its own motion. (a) General rule. The MAC may decide on its own motion to review a decision or dismissal issued by an ALJ. CMS or the IRE...

  5. 42 CFR 423.2110 - MAC reviews on its own motion.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 3 2012-10-01 2012-10-01 false MAC reviews on its own motion. 423.2110 Section 423..., MAC review, and Judicial Review § 423.2110 MAC reviews on its own motion. (a) General rule. The MAC may decide on its own motion to review a decision or dismissal issued by an ALJ. CMS or the IRE...

  6. 42 CFR 423.2110 - MAC reviews on its own motion.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 3 2013-10-01 2013-10-01 false MAC reviews on its own motion. 423.2110 Section 423..., MAC review, and Judicial Review § 423.2110 MAC reviews on its own motion. (a) General rule. The MAC may decide on its own motion to review a decision or dismissal issued by an ALJ. CMS or the IRE...

  7. Identifying ChIP-seq enrichment using MACS

    PubMed Central

    Feng, Jianxing; Liu, Tao; Qin, Bo; Zhang, Yong; Liu, Xiaole Shirley

    2013-01-01

    Model-based Analysis of ChIP-seq (MACS) is a computational algorithm that identifies genome-wide locations of transcription/chromatin factor binding or histone modification from ChIP-seq data. MACS consists of four steps: removing redundant reads, adjusting read position, calculating peak enrichment, and estimating the empirical false discovery rate. In this protocol, we provide a detailed demonstration of how to install MACS and how to use it to analyze three common types of ChIP-seq datasets with different characteristics: the sequence-specific transcription factor FoxA1, the histone modification mark H3K4me3 with sharp enrichment, and the H3K36me3 mark with broad enrichment. We also explain how to interpret and visualize the results of MACS analyses. The algorithm requires approximately 3 GB of RAM and 1.5 hours of computing time to analyze a ChIP-seq dataset containing 30 million reads, an estimate that increases with sequence coverage. MACS is open-source and is available from http://liulab.dfci.harvard.edu/MACS. PMID:22936215

  8. LS Channel Estimation and Signal Separation for UHF RFID Tag Collision Recovery on the Physical Layer.

    PubMed

    Duan, Hanjun; Wu, Haifeng; Zeng, Yu; Chen, Yuebin

    2016-01-01

    In a passive ultra-high frequency (UHF) radio-frequency identification (RFID) system, tag collision is generally resolved on a medium access control (MAC) layer. However, some of collided tag signals could be recovered on a physical (PHY) layer and, thus, enhance the identification efficiency of the RFID system. For the recovery on the PHY layer, channel estimation is a critical issue. Good channel estimation will help to recover the collided signals. Existing channel estimates work well for two collided tags. When the number of collided tags is beyond two, however, the existing estimates have more estimation errors. In this paper, we propose a novel channel estimate for the UHF RFID system. It adopts an orthogonal matrix based on the information of preambles which is known for a reader and applies a minimum-mean-square-error (MMSE) criterion to estimate channels. From the estimated channel, we could accurately separate the collided signals and recover them. By means of numerical results, we show that the proposed estimate has lower estimation errors and higher separation efficiency than the existing estimates. PMID:27023560

  9. LS Channel Estimation and Signal Separation for UHF RFID Tag Collision Recovery on the Physical Layer

    PubMed Central

    Duan, Hanjun; Wu, Haifeng; Zeng, Yu; Chen, Yuebin

    2016-01-01

    In a passive ultra-high frequency (UHF) radio-frequency identification (RFID) system, tag collision is generally resolved on a medium access control (MAC) layer. However, some of collided tag signals could be recovered on a physical (PHY) layer and, thus, enhance the identification efficiency of the RFID system. For the recovery on the PHY layer, channel estimation is a critical issue. Good channel estimation will help to recover the collided signals. Existing channel estimates work well for two collided tags. When the number of collided tags is beyond two, however, the existing estimates have more estimation errors. In this paper, we propose a novel channel estimate for the UHF RFID system. It adopts an orthogonal matrix based on the information of preambles which is known for a reader and applies a minimum-mean-square-error (MMSE) criterion to estimate channels. From the estimated channel, we could accurately separate the collided signals and recover them. By means of numerical results, we show that the proposed estimate has lower estimation errors and higher separation efficiency than the existing estimates. PMID:27023560

  10. Ion channels go to Stockholm--this time as proteins.

    PubMed

    Miller, Christopher

    2003-12-18

    The 2003 Nobel Prize in Chemistry was awarded to two structural biologists, Roderick Mackinnon of Rockefeller University and Peter Agre of Johns Hopkins University, for their groundbreaking work on the structure and function of ion channels. In recognition of the outstanding impact that MacKinnon's work has had for neuroscience, Chris Miller traces MacKinnon's scientific path to the Nobel Prize. PMID:14687537

  11. Domain-swapped chain connectivity and gated membrane access in a Fab-mediated crystal of the human TRAAK K+ channel

    PubMed Central

    Brohawn, Stephen G.; Campbell, Ernest B.; MacKinnon, Roderick

    2013-01-01

    TRAAK (TWIK-related arachidonic acid-stimulated K+ channel, K2P4.1) K+ ion channels are expressed predominantly in the nervous system to control cellular resting membrane potential and are regulated by mechanical and chemical properties of the lipid membrane. TRAAK channels are twofold symmetric, which precludes a direct extension of gating mechanisms that close canonical fourfold symmetric K+ channels. We present the crystal structure of human TRAAK in complex with antibody antigen-binding fragments (Fabs) at 2.75-Å resolution. In contrast to a previous structure, this structure reveals a domain-swapped chain connectivity enabled by the helical cap that exchanges two opposing outer helices 180° around the channel. An unrelated conformational change of an inner helix seals a side opening to the membrane bilayer and is associated with structural changes around the K+-selectivity filter that may have implications for mechanosensitivity and gating of TRAAK channels. PMID:23341632

  12. Anaesthesia with sevoflurane in pigeons: minimal anaesthetic concentration (MAC) determination and investigation of cardiorespiratory variables at 1 MAC.

    PubMed

    Botman, J; Gabriel, F; Dugdale, A H A; Vandeweerd, J-M

    2016-05-28

    The objective of the study was to determine the minimal anaesthetic concentration (MAC) of sevoflurane (SEVO) in pigeons and investigate the effects of 1 MAC SEVO anaesthesia on cardiovascular and respiratory variables compared with the awake state. This is a prospective, experimental study. Animals were seven healthy adult pigeons. After acclimatisation to handling, heart rate (HR), heart rhythm, respiratory rate (fR), end-expired carbon dioxide tension (PE'CO2), inspired CO2 tension, indirect systolic arterial blood pressure (SAP) and cloacal temperature were measured to determine baseline, 'awake' values. Pigeons were then anaesthetised with SEVO and MAC was determined by the 'bracketing' method. The same variables were monitored during a 40 minute period at 1.0 MAC SEVO for each bird. Mean MAC was 3.0±0.6 per cent for SEVO. During maintenance of anaesthesia at 1.0 MAC, SAP decreased significantly (P<0.001) without any significant change in HR. Although PE'CO2 increased significantly (P=0.001) despite an increase in fR, awake PE'CO2 values were unexpectedly low. Sinus arrhythmias were detected in two birds under SEVO anaesthesia. The times to tracheal intubation and to recovery were 2.5±0.7 and 6.4±1.7 minutes, respectively. Recovery was rapid and uneventful in all birds. In conclusion, SEVO is suitable for anaesthesia in pigeons. PMID:27083873

  13. Staged optimization algorithms based MAC dynamic bandwidth allocation for OFDMA-PON

    NASA Astrophysics Data System (ADS)

    Liu, Yafan; Qian, Chen; Cao, Bingyao; Dun, Han; Shi, Yan; Zou, Junni; Lin, Rujian; Wang, Min

    2016-06-01

    Orthogonal frequency division multiple access passive optical network (OFDMA-PON) has being considered as a promising solution for next generation PONs due to its high spectral efficiency and flexible bandwidth allocation scheme. In order to take full advantage of these merits of OFDMA-PON, a high-efficiency medium access control (MAC) dynamic bandwidth allocation (DBA) scheme is needed. In this paper, we propose two DBA algorithms which can act on two different stages of a resource allocation process. To achieve higher bandwidth utilization and ensure the equity of ONUs, we propose a DBA algorithm based on frame structure for the stage of physical layer mapping. Targeting the global quality of service (QoS) of OFDMA-PON, we propose a full-range DBA algorithm with service level agreement (SLA) and class of service (CoS) for the stage of bandwidth allocation arbitration. The performance of the proposed MAC DBA scheme containing these two algorithms is evaluated using numerical simulations. Simulations of a 15 Gbps network with 1024 sub-carriers and 32 ONUs demonstrate the maximum network throughput of 14.87 Gbps and the maximum packet delay of 1.45 ms for the highest priority CoS under high load condition.

  14. The properties, functions, and pathophysiology of maxi-anion channels.

    PubMed

    Sabirov, Ravshan Z; Merzlyak, Petr G; Islam, Md Rafiqul; Okada, Toshiaki; Okada, Yasunobu

    2016-03-01

    The maxi-anion channels (MACs) with a unitary conductance of 200-500 pS are detected in virtually every part of the whole body and found in cells from mammals to amphibia. The channels are normally silent but can be activated by physiologically/pathophysiologically relevant stimuli, such as osmotic, salt, metabolic, oxidative, and mechanical stresses, receptor activation, serum, heat, and intracellular Ca(2+) rise. In some MACs, protein dephosphorylation is associated with channel activation. Among MACs so far studied, around 60 % (designated here as Maxi-Cl) possess, in common, the following phenotypical biophysical properties: (1) unitary conductance of 300-400 pS, (2) a linear current-voltage relationship, (3) high anion-to-cation selectivity with PCl/Pcation of >8, and (4) inactivation at positive and negative potentials over a certain level (usually ±20 mV). The pore configuration of the Maxi-Cl is asymmetrical with extracellular and intracellular radii of ∼1.42 and ∼1.16 nm, respectively, and a medial constriction down to ∼0.55-0.75 nm. The classical function of MACs is control of membrane potential and fluid movement. Permeability to ATP and glutamate turns MACs to signaling channels in purinergic and glutamatergic signal transduction defining them as a perspective target for drug discovery. The molecular identification is an urgent task that would greatly promote the developments in this field. A possible relationship between these channels and some transporters is discussed. PMID:26733413

  15. Easily Accessible Polycyclic Amines that Inhibit the Wild-Type and Amantadine-Resistant Mutants of the M2 Channel of Influenza A Virus

    PubMed Central

    2015-01-01

    Amantadine inhibits the M2 proton channel of influenza A virus, yet most of the currently circulating strains of the virus carry mutations in the M2 protein that render the virus amantadine-resistant. While most of the research on novel amantadine analogues has revolved around the synthesis of novel adamantane derivatives, we have recently found that other polycyclic scaffolds effectively block the M2 proton channel, including amantadine-resistant mutant channels. In this work, we have synthesized and characterized a series of pyrrolidine derivatives designed as analogues of amantadine. Inhibition of the wild-type M2 channel and the A/M2-S31N, A/M2-V27A, and A/M2-L26F mutant forms of the channel were measured in Xenopus oocytes using two-electrode voltage clamp assays. Most of the novel compounds inhibited the wild-type ion channel in the low micromolar range. Of note, two of the compounds inhibited the amantadine-resistant A/M2-V27A and A/M2-L26F mutant ion channels with submicromolar and low micromolar IC50, respectively. None of the compounds was found to inhibit the S31N mutant ion channel. PMID:24941437

  16. SACRB-MAC: A High-Capacity MAC Protocol for Cognitive Radio Sensor Networks in Smart Grid

    PubMed Central

    Yang, Zhutian; Shi, Zhenguo; Jin, Chunlin

    2016-01-01

    The Cognitive Radio Sensor Network (CRSN) is considered as a viable solution to enhance various aspects of the electric power grid and to realize a smart grid. However, several challenges for CRSNs are generated due to the harsh wireless environment in a smart grid. As a result, throughput and reliability become critical issues. On the other hand, the spectrum aggregation technique is expected to play an important role in CRSNs in a smart grid. By using spectrum aggregation, the throughput of CRSNs can be improved efficiently, so as to address the unique challenges of CRSNs in a smart grid. In this regard, we proposed Spectrum Aggregation Cognitive Receiver-Based MAC (SACRB-MAC), which employs the spectrum aggregation technique to improve the throughput performance of CRSNs in a smart grid. Moreover, SACRB-MAC is a receiver-based MAC protocol, which can provide a good reliability performance. Analytical and simulation results demonstrate that SACRB-MAC is a promising solution for CRSNs in a smart grid. PMID:27043573

  17. SACRB-MAC: A High-Capacity MAC Protocol for Cognitive Radio Sensor Networks in Smart Grid.

    PubMed

    Yang, Zhutian; Shi, Zhenguo; Jin, Chunlin

    2016-01-01

    The Cognitive Radio Sensor Network (CRSN) is considered as a viable solution to enhance various aspects of the electric power grid and to realize a smart grid. However, several challenges for CRSNs are generated due to the harsh wireless environment in a smart grid. As a result, throughput and reliability become critical issues. On the other hand, the spectrum aggregation technique is expected to play an important role in CRSNs in a smart grid. By using spectrum aggregation, the throughput of CRSNs can be improved efficiently, so as to address the unique challenges of CRSNs in a smart grid. In this regard, we proposed Spectrum Aggregation Cognitive Receiver-Based MAC (SACRB-MAC), which employs the spectrum aggregation technique to improve the throughput performance of CRSNs in a smart grid. Moreover, SACRB-MAC is a receiver-based MAC protocol, which can provide a good reliability performance. Analytical and simulation results demonstrate that SACRB-MAC is a promising solution for CRSNs in a smart grid. PMID:27043573

  18. Micromechanics Analysis Code With Generalized Method of Cells (MAC/GMC): User Guide. Version 3

    NASA Technical Reports Server (NTRS)

    Arnold, S. M.; Bednarcyk, B. A.; Wilt, T. E.; Trowbridge, D.

    1999-01-01

    The ability to accurately predict the thermomechanical deformation response of advanced composite materials continues to play an important role in the development of these strategic materials. Analytical models that predict the effective behavior of composites are used not only by engineers performing structural analysis of large-scale composite components but also by material scientists in developing new material systems. For an analytical model to fulfill these two distinct functions it must be based on a micromechanics approach which utilizes physically based deformation and life constitutive models and allows one to generate the average (macro) response of a composite material given the properties of the individual constituents and their geometric arrangement. Here the user guide for the recently developed, computationally efficient and comprehensive micromechanics analysis code, MAC, who's predictive capability rests entirely upon the fully analytical generalized method of cells, GMC, micromechanics model is described. MAC/ GMC is a versatile form of research software that "drives" the double or triply periodic micromechanics constitutive models based upon GMC. MAC/GMC enhances the basic capabilities of GMC by providing a modular framework wherein 1) various thermal, mechanical (stress or strain control) and thermomechanical load histories can be imposed, 2) different integration algorithms may be selected, 3) a variety of material constitutive models (both deformation and life) may be utilized and/or implemented, and 4) a variety of fiber architectures (both unidirectional, laminate and woven) may be easily accessed through their corresponding representative volume elements contained within the supplied library of RVEs or input directly by the user, and 5) graphical post processing of the macro and/or micro field quantities is made available.

  19. Vehicle Health Management Communications Requirements for AeroMACS

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.; Clements, Donna J.; Apaza, Rafael D.

    2012-01-01

    As the development of standards for the aeronautical mobile airport communications system (AeroMACS) progresses, the process of identifying and quantifying appropriate uses for the system is progressing. In addition to defining important elements of AeroMACS standards, indentifying the systems uses impacts AeroMACS bandwidth requirements. Although an initial 59 MHz spectrum allocation for AeroMACS was established in 2007, the allocation may be inadequate; studies have indicated that 100 MHz or more of spectrum may be required to support airport surface communications. Hence additional spectrum allocations have been proposed. Vehicle health management (VHM) systems, which can produce large volumes of vehicle health data, were not considered in the original bandwidth requirements analyses, and are therefore of interest in supporting proposals for additional AeroMACS spectrum. VHM systems are an emerging development in air vehicle safety, and preliminary estimates of the amount of data that will be produced and transmitted off an aircraft, both in flight and on the ground, have been prepared based on estimates of data produced by on-board vehicle health sensors and initial concepts of data processing approaches. This allowed an initial estimate of VHM data transmission requirements for the airport surface. More recently, vehicle-level systems designed to process and analyze VHM data and draw conclusions on the current state of vehicle health have been undergoing testing and evaluation. These systems make use of vehicle system data that is mostly different from VHM data considered previously for airport surface transmission, and produce processed system outputs that will be also need to be archived, thus generating additional data load for AeroMACS. This paper provides an analysis of airport surface data transmission requirements resulting from the vehicle level reasoning systems, within the context of overall VHM data requirements.

  20. Data representations in PDP-10 MacLISP

    NASA Technical Reports Server (NTRS)

    Steele, G. L., Jr.

    1977-01-01

    The internal representations of the various MacLISP data types are presented and discussed. Certain implementation tradeoffs are considered. The ultimate decisions on these tradeoffs are discussed in the light of MacLISP's prime objective of being an efficient high-level language for the implementation of large systems such as MACSYMA. The basic strategy of garbage collection is outlined, with reference to the specific representations involved. Certain clever tricks are explained and justified. The address space crunch is explained and some alternative solutions explored.

  1. A New MAC Address Spoofing Detection Technique Based on Random Forests.

    PubMed

    Alotaibi, Bandar; Elleithy, Khaled

    2016-01-01

    Media access control (MAC) addresses in wireless networks can be trivially spoofed using off-the-shelf devices. The aim of this research is to detect MAC address spoofing in wireless networks using a hard-to-spoof measurement that is correlated to the location of the wireless device, namely the received signal strength (RSS). We developed a passive solution that does not require modification for standards or protocols. The solution was tested in a live test-bed (i.e., a wireless local area network with the aid of two air monitors acting as sensors) and achieved 99.77%, 93.16% and 88.38% accuracy when the attacker is 8-13 m, 4-8 m and less than 4 m away from the victim device, respectively. We implemented three previous methods on the same test-bed and found that our solution outperforms existing solutions. Our solution is based on an ensemble method known as random forests. PMID:26927103

  2. A New MAC Address Spoofing Detection Technique Based on Random Forests

    PubMed Central

    Alotaibi, Bandar; Elleithy, Khaled

    2016-01-01

    Media access control (MAC) addresses in wireless networks can be trivially spoofed using off-the-shelf devices. The aim of this research is to detect MAC address spoofing in wireless networks using a hard-to-spoof measurement that is correlated to the location of the wireless device, namely the received signal strength (RSS). We developed a passive solution that does not require modification for standards or protocols. The solution was tested in a live test-bed (i.e., a wireless local area network with the aid of two air monitors acting as sensors) and achieved 99.77%, 93.16% and 88.38% accuracy when the attacker is 8–13 m, 4–8 m and less than 4 m away from the victim device, respectively. We implemented three previous methods on the same test-bed and found that our solution outperforms existing solutions. Our solution is based on an ensemble method known as random forests. PMID:26927103

  3. An Energy Efficient MAC Protocol for Multi-Hop Swallowable Body Sensor Networks

    PubMed Central

    Lin, Lin; Yang, Chengfeng; Wong, Kai Juan; Yan, Hao; Shen, Junwen; Phee, Soo Jay

    2014-01-01

    Swallowable body sensor networks (BSNs) are composed of sensors which are swallowed by patients and send the collected data to the outside coordinator. These sensors are energy constraint and the batteries are difficult to be replaced. The medium access control (MAC) protocol plays an important role in energy management. This paper investigates an energy efficient MAC protocol design for swallowable BSNs. Multi-hop communication is analyzed and proved more energy efficient than single-hop communication within the human body when the circuitry power is low. Based on this result, a centrally controlled time slotting schedule is proposed. The major workload is shifted from the sensors to the coordinator. The coordinator collects the path-loss map and calculates the schedules, including routing, slot assignment and transmission power. Sensor nodes follow the schedules to send data in a multi-hop way. The proposed protocol is compared with the IEEE 802.15.6 protocol in terms of energy consumption. The results show that it is more energy efficient than IEEE 802.15.6 for swallowable BSN scenarios. PMID:25330049

  4. An energy efficient MAC protocol for multi-hop swallowable body sensor networks.

    PubMed

    Lin, Lin; Yang, Chengfeng; Wong, Kai Juan; Yan, Hao; Shen, Junwen; Phee, Soo Jay

    2014-01-01

    Swallowable body sensor networks (BSNs) are composed of sensors which are swallowed by patients and send the collected data to the outside coordinator. These sensors are energy constraint and the batteries are difficult to be replaced. The medium access control (MAC) protocol plays an important role in energy management. This paper investigates an energy efficient MAC protocol design for swallowable BSNs. Multi-hop communication is analyzed and proved more energy efficient than single-hop communication within the human body when the circuitry power is low. Based on this result, a centrally controlled time slotting schedule is proposed. The major workload is shifted from the sensors to the coordinator. The coordinator collects the path-loss map and calculates the schedules, including routing, slot assignment and transmission power. Sensor nodes follow the schedules to send data in a multi-hop way. The proposed protocol is compared with the IEEE 802.15.6 protocol in terms of energy consumption. The results show that it is more energy efficient than IEEE 802.15.6 for swallowable BSN scenarios. PMID:25330049

  5. Proposal and Rationale for the Development of a Mac Lab.

    ERIC Educational Resources Information Center

    Bordner, Marsha

    At Clark State Community College (CSCC), in Ohio, faculty in the Commercial Art and English departments have investigated and debated the best uses for a Mac Lab. Computer needs for the Commercial Art Program were determined through visits to local businesses that produce art on a commercial level; to local secondary school commercial art…

  6. Integrated, Kerberized Login on MacOS X

    NASA Technical Reports Server (NTRS)

    Hotz, Henry B.

    2006-01-01

    Context for this information. MacOS X login process and available hooks. Authorization Services configuration. Authorization Services plug-in s. Kerberos plug-in s. Other bugs and recommendations. Authorization Services Called by loginwindow, screen saver and fast user switching. It calls Directory Services, Login Hook, and Login Items (System Preferences).

  7. God, Sport Philosophy, Kinesiology: A MacIntyrean Examination

    ERIC Educational Resources Information Center

    Twietmeyer, Gregg

    2015-01-01

    Sport philosophy is in crisis. This subdiscipline of kinesiology garners little to no respect and few tenure track lines in kinesiology departments. Why is this the case? Why isn't philosophy held in greater esteem? Is it possible that philosopher Alasdair MacIntyre's (2009) diagnosis found in "God, Philosophy, Universities" could…

  8. MAC/FAC: A Model of Similarity-Based Retrieval.

    ERIC Educational Resources Information Center

    Forbus, Kenneth D.; And Others

    1995-01-01

    Presents MAC/FAC, a model of similarity-based retrieval that attempts to capture psychological phenomena; discusses its limitations and extensions, its relationship with other retrieval models, and its placement in the context of other work on the nature of similarity. Examines the utility of the model through psychological experiments and…

  9. 12 CFR 615.5174 - Farmer Mac securities.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    .... Annually, your board of directors must review these policies and the performance of your Farmer Mac.... (d) Stress Test. You must perform stress tests on mortgage securities that are issued or guaranteed... fails a stress test, you must divest it as required by § 615.5143....

  10. The MacArthur Foundation in Nigeria: Report on Activities

    ERIC Educational Resources Information Center

    John D. and Catherine T. MacArthur Foundation, 2009

    2009-01-01

    In 2007, Nigeria passed an important milestone: one elected government passed power to another for the first time in the nation's history. Though imperfect, the poll demonstrated powerfully that Nigeria's representative democracy was not a transient phase between periods of military repression but a growing reality. For 20 years, the MacArthur…

  11. 42 CFR 405.1118 - Obtaining evidence from the MAC.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Obtaining evidence from the MAC. 405.1118 Section 405.1118 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM FEDERAL HEALTH INSURANCE FOR THE AGED AND DISABLED Determinations, Redeterminations, Reconsiderations, and Appeals Under...

  12. Modeling Woven Polymer Matrix Composites with MAC/GMC

    NASA Technical Reports Server (NTRS)

    Bednarcyk, Brett A.; Arnold, Steven M. (Technical Monitor)

    2000-01-01

    NASA's Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC) is used to predict the elastic properties of plain weave polymer matrix composites (PMCs). The traditional one step three-dimensional homogertization procedure that has been used in conjunction with MAC/GMC for modeling woven composites in the past is inaccurate due to the lack of shear coupling inherent to the model. However, by performing a two step homogenization procedure in which the woven composite repeating unit cell is homogenized independently in the through-thickness direction prior to homogenization in the plane of the weave, MAC/GMC can now accurately model woven PMCs. This two step procedure is outlined and implemented, and predictions are compared with results from the traditional one step approach and other models and experiments from the literature. Full coupling of this two step technique with MAC/ GMC will result in a widely applicable, efficient, and accurate tool for the design and analysis of woven composite materials and structures.

  13. What if MacGyver Taught Physical Education?

    ERIC Educational Resources Information Center

    Marston, Rip; Leech, Trey

    2014-01-01

    In an era of rising childhood obesity rates, many physical educators find themselves with declining financial resources. Similar to how MacGyver had to do when he was in a bind on his self-titled television show, physical educators need to think creatively when providing equipment for use by their students. The problem that has been identified is:…

  14. 42 CFR 422.608 - Medicare Appeals Council (MAC) review.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 3 2012-10-01 2012-10-01 false Medicare Appeals Council (MAC) review. 422.608 Section 422.608 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM (CONTINUED) MEDICARE ADVANTAGE PROGRAM Grievances,...

  15. 42 CFR 422.608 - Medicare Appeals Council (MAC) review.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 3 2013-10-01 2013-10-01 false Medicare Appeals Council (MAC) review. 422.608 Section 422.608 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM (CONTINUED) MEDICARE ADVANTAGE PROGRAM Grievances,...

  16. 42 CFR 422.608 - Medicare Appeals Council (MAC) review.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 3 2010-10-01 2010-10-01 false Medicare Appeals Council (MAC) review. 422.608 Section 422.608 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM MEDICARE ADVANTAGE PROGRAM Grievances, Organization...

  17. 42 CFR 423.1974 - Medicare Appeals Council (MAC) review.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 3 2014-10-01 2014-10-01 false Medicare Appeals Council (MAC) review. 423.1974 Section 423.1974 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM (CONTINUED) VOLUNTARY MEDICARE PRESCRIPTION DRUG BENEFIT...

  18. 42 CFR 423.1974 - Medicare Appeals Council (MAC) review.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 3 2010-10-01 2010-10-01 false Medicare Appeals Council (MAC) review. 423.1974 Section 423.1974 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM VOLUNTARY MEDICARE PRESCRIPTION DRUG BENEFIT Reopening, ALJ...

  19. 42 CFR 423.1974 - Medicare Appeals Council (MAC) review.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 3 2011-10-01 2011-10-01 false Medicare Appeals Council (MAC) review. 423.1974 Section 423.1974 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM VOLUNTARY MEDICARE PRESCRIPTION DRUG BENEFIT Reopening, ALJ...

  20. 42 CFR 422.608 - Medicare Appeals Council (MAC) review.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 3 2011-10-01 2011-10-01 false Medicare Appeals Council (MAC) review. 422.608 Section 422.608 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM MEDICARE ADVANTAGE PROGRAM Grievances, Organization...

  1. 42 CFR 423.1974 - Medicare Appeals Council (MAC) review.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 3 2012-10-01 2012-10-01 false Medicare Appeals Council (MAC) review. 423.1974 Section 423.1974 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM (CONTINUED) VOLUNTARY MEDICARE PRESCRIPTION DRUG BENEFIT...

  2. 42 CFR 422.608 - Medicare Appeals Council (MAC) review.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 3 2014-10-01 2014-10-01 false Medicare Appeals Council (MAC) review. 422.608 Section 422.608 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM (CONTINUED) MEDICARE ADVANTAGE PROGRAM Grievances,...

  3. 42 CFR 423.1974 - Medicare Appeals Council (MAC) review.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 3 2013-10-01 2013-10-01 false Medicare Appeals Council (MAC) review. 423.1974 Section 423.1974 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM (CONTINUED) VOLUNTARY MEDICARE PRESCRIPTION DRUG BENEFIT...

  4. 12 CFR 615.5174 - Farmer Mac securities.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 7 2012-01-01 2012-01-01 false Farmer Mac securities. 615.5174 Section 615.5174 Banks and Banking FARM CREDIT ADMINISTRATION FARM CREDIT SYSTEM FUNDING AND FISCAL AFFAIRS, LOAN POLICIES AND OPERATIONS, AND FUNDING OPERATIONS Property, Transfers of Capital, and Other Investments §...

  5. 12 CFR 615.5174 - Farmer Mac securities.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 7 2013-01-01 2013-01-01 false Farmer Mac securities. 615.5174 Section 615.5174 Banks and Banking FARM CREDIT ADMINISTRATION FARM CREDIT SYSTEM FUNDING AND FISCAL AFFAIRS, LOAN POLICIES AND OPERATIONS, AND FUNDING OPERATIONS Property, Transfers of Capital, and Other Investments §...

  6. 12 CFR 615.5174 - Farmer Mac securities.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 6 2011-01-01 2011-01-01 false Farmer Mac securities. 615.5174 Section 615.5174 Banks and Banking FARM CREDIT ADMINISTRATION FARM CREDIT SYSTEM FUNDING AND FISCAL AFFAIRS, LOAN POLICIES AND OPERATIONS, AND FUNDING OPERATIONS Property, Transfers of Capital, and Other Investments §...

  7. 12 CFR 615.5174 - Farmer Mac securities.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 7 2014-01-01 2014-01-01 false Farmer Mac securities. 615.5174 Section 615.5174 Banks and Banking FARM CREDIT ADMINISTRATION FARM CREDIT SYSTEM FUNDING AND FISCAL AFFAIRS, LOAN POLICIES AND OPERATIONS, AND FUNDING OPERATIONS Property, Transfers of Capital, and Other Investments §...

  8. Bacterial Ion Channels.

    PubMed

    Compton, Emma L R; Mindell, Joseph A

    2010-09-01

    Bacterial ion channels were known, but only in special cases, such as outer membrane porins in Escherichia coli and bacterial toxins that form pores in their target (bacterial or mammalian) membranes. The exhaustive coverage provided by a decade of bacterial genome sequencing has revealed that ion channels are actually widespread in bacteria, with homologs of a broad range of mammalian channel proteins coded throughout the bacterial and archaeal kingdoms. This review discusses four groups of bacterial channels: porins, mechano-sensitive (MS) channels, channel-forming toxins, and bacterial homologs of mammalian channels. The outer membrane (OM) of gram-negative bacteria blocks access of essential nutrients; to survive, the cell needs to provide a mechanism for nutrients to penetrate the OM. Porin channels provide this access by forming large, nonspecific aqueous pores in the OM that allow ions and vital nutrients to cross it and enter the periplasm. MS channels act as emergency release valves, allowing solutes to rapidly exit the cytoplasm and to dissipate the large osmotic disparity between the internal and external environments. MS channels are remarkable in that they do this by responding to forces exerted by the membrane itself. Some bacteria produce toxic proteins that form pores in trans, attacking and killing other organisms by virtue of their pore formation. The review focuses on those bacterial toxins that kill other bacteria, specifically the class of proteins called colicins. Colicins reveal the dangers of channel formation in the plasma membrane, since they kill their targets with exactly that approach. PMID:26443789

  9. 42 CFR 405.1110 - MAC reviews on its own motion.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false MAC reviews on its own motion. 405.1110 Section 405....1110 MAC reviews on its own motion. (a) General rule. The MAC may decide on its own motion to review a decision or dismissal issued by an ALJ. CMS or any of its contractors may refer a case to the MAC for it...

  10. 42 CFR 405.1110 - MAC reviews on its own motion.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 2 2011-10-01 2011-10-01 false MAC reviews on its own motion. 405.1110 Section 405....1110 MAC reviews on its own motion. (a) General rule. The MAC may decide on its own motion to review a decision or dismissal issued by an ALJ. CMS or any of its contractors may refer a case to the MAC for it...

  11. Photocopy of drawing (original drawing of MacDill Field in possession ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of drawing (original drawing of MacDill Field in possession of MacDill Air Force Base, Civil Engineering, Tampa, Florida; 1952 architectural drawings by Strategic Air Command, MacDill Air Force Base) BASE LAYOUT, 1952 - MacDill Air Force Base, Bounded by City of Tampa North, Tampa Bay South, Old Tampa Bay West, & Hillsborough Bay East, Tampa, Hillsborough County, FL

  12. 42 CFR 405.1110 - MAC reviews on its own motion.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 2 2013-10-01 2013-10-01 false MAC reviews on its own motion. 405.1110 Section 405....1110 MAC reviews on its own motion. (a) General rule. The MAC may decide on its own motion to review a decision or dismissal issued by an ALJ. CMS or any of its contractors may refer a case to the MAC for it...

  13. 42 CFR 405.1110 - MAC reviews on its own motion.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 2 2012-10-01 2012-10-01 false MAC reviews on its own motion. 405.1110 Section 405....1110 MAC reviews on its own motion. (a) General rule. The MAC may decide on its own motion to review a decision or dismissal issued by an ALJ. CMS or any of its contractors may refer a case to the MAC for it...

  14. 42 CFR 405.1110 - MAC reviews on its own motion.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 2 2014-10-01 2014-10-01 false MAC reviews on its own motion. 405.1110 Section 405....1110 MAC reviews on its own motion. (a) General rule. The MAC may decide on its own motion to review a decision or dismissal issued by an ALJ. CMS or any of its contractors may refer a case to the MAC for it...

  15. 75 FR 69154 - Land Release for Long Island MacArthur Airport

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-10

    ... Federal Aviation Administration Land Release for Long Island MacArthur Airport AGENCY: Federal Aviation... requesting public comment on the Long Island MacArthur Airport (ISP), Ronkonkoma, New York, notice of...-aeronautical development. The parcel is located on the northeast corner of the Long Island MacArthur...

  16. 33 CFR 165.768 - Security Zone; MacDill Air Force Base, Tampa Bay, FL.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Security Zone; MacDill Air Force....768 Security Zone; MacDill Air Force Base, Tampa Bay, FL. (a) Location. The following area is a... title. All waters within Tampa Bay, Florida in the vicinity of MacDill Air Force Base,...

  17. 33 CFR 165.768 - Security Zone; MacDill Air Force Base, Tampa Bay, FL.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Security Zone; MacDill Air Force....768 Security Zone; MacDill Air Force Base, Tampa Bay, FL. (a) Location. The following area is a... title. All waters within Tampa Bay, Florida in the vicinity of MacDill Air Force Base,...

  18. 33 CFR 165.768 - Security Zone; MacDill Air Force Base, Tampa Bay, FL.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone; MacDill Air Force....768 Security Zone; MacDill Air Force Base, Tampa Bay, FL. (a) Location. The following area is a... title. All waters within Tampa Bay, Florida in the vicinity of MacDill Air Force Base,...

  19. 33 CFR 165.768 - Security Zone; MacDill Air Force Base, Tampa Bay, FL.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Security Zone; MacDill Air Force....768 Security Zone; MacDill Air Force Base, Tampa Bay, FL. (a) Location. The following area is a... title. All waters within Tampa Bay, Florida in the vicinity of MacDill Air Force Base,...

  20. 33 CFR 165.768 - Security Zone; MacDill Air Force Base, Tampa Bay, FL.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Security Zone; MacDill Air Force....768 Security Zone; MacDill Air Force Base, Tampa Bay, FL. (a) Location. The following area is a... title. All waters within Tampa Bay, Florida in the vicinity of MacDill Air Force Base,...

  1. MacMouse. Developing Preschool Readiness Concepts and Skills with HyperCard and MacRecorder.

    ERIC Educational Resources Information Center

    Fitterman, L. Jeffrey

    Through developments with the use of the "Apple Macintosh" computer, "HyperCard," and "MacRecorder," children in preschool handicapped programs are now capable of participating in appropriate computerized learning experiences. "HyperCard" allows educators to produce their own computerized instructional lessons with a software program that…

  2. Space Station multiple access communications system

    NASA Technical Reports Server (NTRS)

    Olson, Nanci A.

    1986-01-01

    The development of a multiple access communications system (MACS) for the space-to-space communications on the Space Station is discussed. The communications capabilities of the FHMA, CDMA, TDMA, SDMA, and FDMA techniques are evaluated; FDMA was selected for the space-to-space communications on the Space Station because of its lower complexity and growth capability. The proposed space-to-space multiple access system for the Space Station is a digitally modulated Ku-band FDMA system with a distributed architecture; this system would transmit on frequencies between 13.4 and 13.7 GHz and receive on frequencies between 14.6 and 14.89 GHz, and the bandwidth will support seven high-data-rate users and 12 low-data-rate users. The IF components and antennas for the MACS are examined. A multiple access breadboard design is described.

  3. An energy-efficient media access control protocol for chain-type wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Chen, Chang Wen

    2005-06-01

    We present in this paper an energy efficient media access control (MAC) protocol for chain-type wireless sensor networks. The chain-type sensor networks are fundamentally different from traditional sensor networks in that the sensor nodes in this class of networks are deployed along narrow and elongated geographical areas and form a chain-type topology. Recently, we have successfully developed hierarchical network architecture, sensor deployment strategy, and corresponding network initialization and operation protocols for this class of sensor networks. In this paper, we present a novel TDMA scheduling protocol that takes full advantages of the available channel reuse inherent in the chain-type sensor networks to develop energy efficient and high data throughput MAC protocols for sensor data transmission. The synchronized TDMA scheduling allows the nodes to power on only when it is scheduled to send and receive and therefore results in additional energy saving. Within a cluster, parallel transmission is made possible because of the linear distribution of nodes within the chain-type topology and this yields the desired high throughput. Preliminary simulations have been carried out to show that the proposed TDMA scheduling outperforms the well-know SMAC scheme in terms of energy efficiency and data throughput under various duty cycles.

  4. Unstable manifolds for the MacKay approximate renormalisation

    NASA Astrophysics Data System (ADS)

    Stark, Jaroslav

    1989-01-01

    For a renormalisation of a critical phenomenon in some class of dynamical systems, it is the unstable manifolds of the critical set which give the universal families which describe the critical transition. In this paper, we study such manifolds for the MacKay [1988] approximate renormalisation scheme which models the breakup of invariant circles of arbitrary rotation number in area-preserving twist maps. We derive a number of properties of the unstable manifolds and then discuss the implications of these to the full renormalisation. In particular a) we suggest the importance of continuity in the definition of unstable manifolds, and b) show that their structure is similar to that observed numerically by MacKay and Percival [1987] in a related renormalisation. Finally we show that the residues of approximating periodic orbits are bounded above on the critical set.

  5. Preliminary results on B-anti B mixing from MAC

    SciTech Connect

    Hurst, R.

    1987-05-01

    An excess of like-charge dimuons has been observed with the MAC detector in multihadron events produced in e e annihilation at s = 29 GeV. If this excess is attributed to B - anti B mixing, the corresponding value of the mixing parameter chi = GAMMA(B X)/GAMMA(B X) is chi = 0.21/sub -0.15//sup +0.25/ and chi > 0.02 at 90% C.L.

  6. A Rosenzweig-MacArthur (1963) Criterion for the Chemostat

    PubMed Central

    Cheng, Yuanji

    2016-01-01

    The Rosenzweig-MacArthur (1963) criterion is a graphical criterion that has been widely used for elucidating the local stability properties of the Gause (1934) type predator-prey systems. It has not been stated whether a similar criterion holds for models with explicit resource dynamics (Kooi et al. (1998)), like the chemostat model. In this paper we use the implicit function theorem and implicit derivatives for proving that a similar graphical criterion holds under chemostat conditions, too. PMID:27517080

  7. Bartonella henselae inhibits apoptosis in Mono Mac 6 cells.

    PubMed

    Kempf, Volkhard A J; Schairer, Annette; Neumann, Diana; Grassl, Guntram A; Lauber, Kirsten; Lebiedziejewski, Maria; Schaller, Martin; Kyme, Pierre; Wesselborg, Sebastian; Autenrieth, Ingo B

    2005-01-01

    Bartonella henselae causes the vasculoproliferative disorders bacillary angiomatosis and peliosis probably resulting from the release of vasculoendothelial growth factor (VEGF) from infected epithelial or monocytic host cells. Here we demonstrate that B. henselae in addition to VEGF induction was also capable of inhibiting the endogenous sucide programme of monocytic host cells. Our results show that B. henselae inhibits pyrrolidine dithiocarbamate (PDTC)-induced apoptosis in Mono Mac 6 cells. B. henselae was observed to be present in a vacuolic compartment of Mono Mac 6 cells. Direct contact of B. henselae with Mono Mac 6 cells was crucial for inhibition of apoptosis as shown by the use of a two-chamber model. Inhibition of apoptosis was paralleled by diminished caspase-3 activity which was significantly reduced in PDTC-stimulated and B. henselae-infected cells. The anti-apoptotic effect of B. henselae was accompanied by (i) the activation of the transcription factor NF-kappaB and (ii) the induction of cellular inhibitor of apoptosis proteins-1 and -2 (cIAP-1, -2). Our results suggest a new synergistic mechanism in B. henselae pathogenicity by (i) inhibition of host cell apoptosis via activation of NF-kappaB and (ii) induction of host cell VEGF secretion. PMID:15617526

  8. MacA, a periplasmic membrane fusion protein of the macrolide transporter MacAB-TolC, binds lipopolysaccharide core specifically and with high affinity.

    PubMed

    Lu, Shuo; Zgurskaya, Helen I

    2013-11-01

    The Escherichia coli MacAB-TolC transporter has been implicated in efflux of macrolide antibiotics and secretion of enterotoxin STII. In this study, we found that purified MacA, a periplasmic membrane fusion protein, contains one tightly bound rough core lipopolysaccharide (R-LPS) molecule per MacA molecule. R-LPS was bound specifically to MacA protein with affinity exceeding that of polymyxin B. Sequence analyses showed that MacA contains two high-density clusters of positively charged amino acid residues located in the cytoplasmic N-terminal domain and the periplasmic C-terminal domain. Substitutions in the C-terminal cluster reducing the positive-charge density completely abolished binding of R-LPS. At the same time, these substitutions significantly reduced the functionality of MacA in the protection of E. coli against macrolides in vivo and in the in vitro MacB ATPase stimulation assays. Taken together, our results suggest that R-LPS or a similar glycolipid is a physiological substrate of MacAB-TolC. PMID:23974027

  9. Conceptualizing ¬the Abstractions of Earthquakes Through an Instructional Sequence Using SeisMac and the Rapid Earthquake Viewer

    NASA Astrophysics Data System (ADS)

    Taber, J.; Hubenthal, M.; Wysession, M.

    2007-12-01

    because they have a physical sense of what the wiggles indicate. As a result students are better positioned to identify S and P arrivals within the complexity of real data available through REV rather than using the canned or artificial data normally associated with a location exercise. REV provides easy access to recent and noteworthy earthquake data via a simple Web interface. Earthquake locations and near-real time ground motion data are accessed via the IRIS Data Management System, and data are automatically processed and selected so that only events with "good" data are presented within REV. Once students have completed the learning sequence using SeisMac, they will be better able to relate the trace of a seismogram to the physical motion of the ground. This can then lead to better understanding of more advanced exercises including detecting the core and finding the Moho. Building on an understanding of the basics of a seismogram, SeisMac can next be used to help student further understand earthquakes by provide a kinesthetic experience to model how hard the Earth shakes during earthquakes. Through another guided exploration students discover that the SeisMac display is calibrated in units of acceleration and can be related to the Modified Mercalli scale. They then compare shaking during an earthquake via video clips and ground shaking maps from the USGS "Did you feel it" Web site to the shaking of personal objects and the laptop.

  10. ABSORBING BOUNDARY TECHNIQUE FOR OPEN CHANNEL FLOWS. (R825200)

    EPA Science Inventory

    An absorbing boundary condition is formulated and applied to the one-dimensional open channel flow equations in conjunction with an explicit MacCormack scheme. The physical flow domain has been truncated by introducing an artificial pseudo-boundary. By using an appropriate bounda...

  11. Preliminary measurements of auroral energy deposition and middle atmosphere electrodynamic response during MAC/Epsilon

    NASA Technical Reports Server (NTRS)

    Goldberg, R. A.

    1989-01-01

    On the nights of October 21 and 28, 1987 (UT), two Nike Orion payloads (NASA 31.066 and 31.067) were launched from Andoya, Norway, as part of the MAC/Epsilon campaign, to study auroral energetics and their effect on the middle atmosphere. Each payload carried instrumentation to measure relativistic electrons from 0.1 to 1.0 MeV in 12 differential channels, and Bremsstrahlung X-rays from greater than 5 to greater than 80 KeV in 5 integral channels. In addition, instrumentation to measure ion densities and electric fields were also included on these and, in the case of 31.066, on other near simultaneous payloads. The first flight, 31.066, was launched under pre-magnetic midnight conditions during relatively stable auroral conditions. Flight 31.067 was launched during post-breakup conditions at which time pulsations of approx. 100 seconds duration were evident. The measured radiations including their spectral characteristics are compared for these two events, to appraise their effect on the electrodynamic properties of the middle atmosphere as determined by other rocket-borne measurements.

  12. Tutorial on optical metropolitan networks: packet format, MAC protocols, and quality of service

    NASA Astrophysics Data System (ADS)

    Atmaca, Tülin; Nguyen, Viet Hung; Popa, Daniel

    2007-11-01

    The unprecedented proliferation of packet-based services such as numerical television, video on demand, is pushing Metropolitan Area Networks (MANs) providers to reconsider their network infrastructures. The existing circuit-based networks are becoming inefficient and costly in supporting the new requirements in terms of quality of service and bandwidth of sporadic packet-based traffic. To solve this problem, new MAN infrastructures are needed. Many propositions of new network solutions were made during the last decade in order to respond to the aforementioned issues, such as Next Generation SONET/SDH, Resilient Packet Ring (RPR). Among others, the optical networking technology appears as a technology of choice for the next generation MANs. The main benefit of optical technology can be resumed in the following terms: huge transmission capacity, high reliability, and high availability. This paper is devoted to provide an overview of the MAN infrastructure, and particularly to its evolution towards optical packet switching (OPS) networks, during the last decades. It also highlights performance issues in optical networking in metro area in terms of optical packet format, medium access control (MAC) protocol and quality of service (QoS), as well as traffic engineering issues. We first begin with a brief state-of-the-art and perspective on optical networking in metropolitan area. Next, we provide the necessary arguments for an answer to the problem of the choice of packet format (fixed format versus variable format) to be adopted in future metropolitan optical packet switching networks. Comparison of different optical packet formats at the electronic to optical (E/O) interface is carried out, followed by the analysis of the impact of optical packet format choices on overall network performance. Then, we explore the performance issue at MAC layer and discuss improvement mechanisms for MAC protocol. Here, fairness and bandwidth utilization issues are specifically

  13. THE LARGEST GRAVITATIONAL LENS: MACS J0717.5+3745 (z = 0.546)

    SciTech Connect

    Zitrin, Adi; Broadhurst, Tom; Rephaeli, Yoel; Sadeh, Sharon

    2009-12-10

    We identify 13 sets of multiply-lensed galaxies around MACS J0717.5+3745 (z = 0.546), outlining a very large tangential critical curve of major axis approx2.'8, filling the field of the Hubble Space Telescope/Advanced Camera for Surveys. The equivalent circular Einstein radius is theta {sub e} = 55'' +- 3'' (at an estimated source redshift of z{sub s} approx 2.5), corresponding to r{sub e} approx = 350 +- 20 kpc at the cluster redshift, nearly three times greater than that of A1689 (r{sub e} approx = 140 kpc for z{sub s} = 2.5). The mass enclosed by this critical curve is very large, 7.4 +- 0.5 x 10{sup 14} M {sub sun} and only weakly model dependent, with a relatively shallow mass profile within r < 250 kpc, reflecting the unrelaxed appearance of this cluster. This shallow profile generates a much higher level of magnification than the well-known relaxed lensing clusters of higher concentration, so that the area of sky exceeding a magnification of >10 times, is approx =3.5square' for sources with z approx = 8, making MACS J0717.5+3745 a compelling target for accessing faint objects at high redshift. We calculate that only one such cluster, with theta {sub e} >= 55'', is predicted within approx10{sup 7} Universes with z >= 0.55, corresponding to a virial mass >=3 x 10{sup 15} M {sub sun}, for the standard LAMBDACDM (WMAP5 parameters with 2sigma uncertainties).

  14. Channel Networks

    NASA Astrophysics Data System (ADS)

    Rinaldo, Andrea; Rodriguez-Iturbe, Ignacio; Rigon, Riccardo

    This review proceeds from Luna Leopold's and Ronald Shreve's lasting accomplishments dealing with the study of random-walk and topologically random channel networks. According to the random perspective, which has had a profound influence on the interpretation of natural landforms, nature's resiliency in producing recurrent networks and landforms was interpreted to be the consequence of chance. In fact, central to models of topologically random networks is the assumption of equal likelihood of any tree-like configuration. However, a general framework of analysis exists that argues that all possible network configurations draining a fixed area are not necessarily equally likely. Rather, a probability P(s) is assigned to a particular spanning tree configuration, say s, which can be generally assumed to obey a Boltzmann distribution: P(s) % e^-H(s)/T, where T is a parameter and H(s) is a global property of the network configuration s related to energetic characters, i.e. its Hamiltonian. One extreme case is the random topology model where all trees are equally likely, i.e. the limit case for T6 4 . The other extreme case is T 6 0, and this corresponds to network configurations that tend to minimize their total energy dissipation to improve their likelihood. Networks obtained in this manner are termed optimal channel networks (OCNs). Observational evidence suggests that the characters of real river networks are reproduced extremely well by OCNs. Scaling properties of energy and entropy of OCNs suggest that large network development is likely to effectively occur at zero temperature (i.e. minimizing its Hamiltonian). We suggest a corollary of dynamic accessibility of a network configuration and speculate towards a thermodynamics of critical self-organization. We thus conclude that both chance and necessity are equally important ingredients for the dynamic origin of channel networks---and perhaps of the geometry of nature.

  15. 42 CFR 423.2110 - MAC reviews on its own motion.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 3 2011-10-01 2011-10-01 false MAC reviews on its own motion. 423.2110 Section 423..., and Judicial Review § 423.2110 MAC reviews on its own motion. (a) General rule. The MAC may decide on its own motion to review a decision or dismissal issued by an ALJ. CMS or the IRE may refer a case...

  16. 42 CFR 423.2110 - MAC reviews on its own motion.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 3 2010-10-01 2010-10-01 false MAC reviews on its own motion. 423.2110 Section 423..., and Judicial Review § 423.2110 MAC reviews on its own motion. (a) General rule. The MAC may decide on its own motion to review a decision or dismissal issued by an ALJ. CMS or the IRE may refer a case...

  17. Mac configuration management at the Los Alamos National Laboratory

    SciTech Connect

    Marcus, Allan B

    2010-01-01

    The Los Alamos National Laboratory (LANL) had a need for central configuration management of non-Windows computers. LANL has three to five thousand Macs and an equal number of Linux based systems. The primary goal was to be able to inventory all non-windows systems and patch Mc OS X systems. LANL examined a number of commercial and open source solutions and ultimately selected Puppet. This paper will discuss why we chose Puppet, how we implemented it, and some lessons we learned along the way.

  18. MQ-MAC: A Multi-Constrained QoS-Aware Duty Cycle MAC for Heterogeneous Traffic in Wireless Sensor Networks

    PubMed Central

    Monowar, Muhammad Mostafa; Rahman, Md. Obaidur; Hong, Choong Seon; Lee, Sungwon

    2010-01-01

    Energy conservation is one of the striking research issues now-a-days for power constrained wireless sensor networks (WSNs) and hence, several duty-cycle based MAC protocols have been devised for WSNs in the last few years. However, assimilation of diverse applications with different QoS requirements (i.e., delay and reliability) within the same network also necessitates in devising a generic duty-cycle based MAC protocol that can achieve both the delay and reliability guarantee, termed as multi-constrained QoS, while preserving the energy efficiency. To address this, in this paper, we propose a Multi-constrained QoS-aware duty-cycle MAC for heterogeneous traffic in WSNs (MQ-MAC). MQ-MAC classifies the traffic based on their multi-constrained QoS demands. Through extensive simulation using ns-2 we evaluate the performance of MQ-MAC. MQ-MAC provides the desired delay and reliability guarantee according to the nature of the traffic classes as well as achieves energy efficiency. PMID:22163439

  19. [Ion channels and water channels--a prerequisite for living cells and electric signals in the brain].

    PubMed

    Storm, Johan F

    2003-12-01

    Water channels and ion channels are membrane proteins that transport water and ions into and out of cells with high selectivity and efficiency. Peter Agre and Roderick MacKinnon were awarded the Nobel Prize in chemistry 2003 for their discoveries of the structure of water channels and ion channel proteins, thus explaining basal mechanisms that are fundamental to all forms of life and in particular to the electrical signalling in the brain. These scientific achievements answer questions that biophysicists and physiologists have discussed since the 19th century. PMID:14713970

  20. Serum Mac-2 binding protein is a novel biomarker for chronic pancreatitis

    PubMed Central

    Maekawa, Tomohiro; Kamada, Yoshihiro; Ebisutani, Yusuke; Ueda, Makiko; Hata, Tomoki; Kawamoto, Koichi; Takamatsu, Shinji; Mizutani, Kayo; Shimomura, Mayuka; Sobajima, Tomoaki; Fujii, Hironobu; Nakayama, Kotarosumitomo; Nishino, Kimihiro; Yamada, Makoto; Kumada, Takashi; Ito, Toshifumi; Eguchi, Hidetoshi; Nagano, Hiroaki; Miyoshi, Eiji

    2016-01-01

    AIM: To determine the efficacy of Mac-2 binding protein (Mac-2bp) for diagnosis of chronic pancreatitis. METHODS: Fifty-nine healthy volunteers (HV), 162 patients with chronic pancreatitis (CP), and 94 patients with pancreatic ductal adenocarcinoma (PDAC) were enrolled in this study. We measured serum Mac-2bp using our developed enzyme-linked immunosorbent assay kit. Additional biochemical variables were measured using an automated analyzer (including aminotransferase, alanine aminotransferase, γ-glutamyltransferase, alkaline phosphatase, triglyceride, C-reactive protein, and amylase levels) or chemiluminescent enzyme immunoassay (carbohydrate antigen 19-9 and carcinoembryonic antigen). The ability of Mac-2bp to predict CP diagnosis accurately was assessed using receiver operating characteristic (ROC) analyses. RESULTS: Serum Mac-2bp levels were significantly increased in CP patients compared to HV (P < 0.0001) and PDAC patients (P < 0.0001). Area under the ROC curve values of Mac-2bp for the discrimination of CP from HV and PDAC were 0.727 and 0.784, respectively. Multivariate analyses demonstrated that serum Mac-2bp levels were independent determinants for CP diagnosis from HV and PDAC patients. Immunohistological staining showed that Mac-2bp was expressed faintly in the pancreas tissues of both CP and PDAC patients. Serum aspartate aminotransferase, alanine aminotransferase, γ-glutamyltransferase, alkaline phosphatase, and triglyceride levels were significantly higher in patients with CP or PDAC. Serum Mac-2bp levels were highly correlated with protein levels of alanine aminotransferase, γ-glutamyltransferase, and C-reactive protein, but not amylase, suggesting that the damaged liver produces Mac-2bp. CONCLUSION: Measurement of serum Mac-2bp may be a novel and useful biomarker for CP diagnosis as well as liver fibrosis in the general population. PMID:27158210

  1. Membrane attack complex (MAC)-mediated damage to spermatozoa: protection of the cells by the presence on their membranes of MAC inhibitory proteins.

    PubMed Central

    Rooney, I A; Davies, A; Morgan, B P

    1992-01-01

    Although antibody and complement are known to cause immobilization and killing of spermatozoa in vitro the components of the complement system mediating these effects remain undefined. Here we have examined the effects of the membrane attack complex (MAC) on spermatozoa and demonstrate that spermatotoxic effects are dependent on assembly of the complete MAC. We subsequently examined the presence and functional significance of the complement regulatory proteins decay accelerating factor (DAF), MAC-inhibiting protein (MIP) and CD59 antigen on spermatozoa. Both DAF and CD59 antigen were present on the membranes of these cells. Neutralization of CD59 antigen with specific antibodies increased the susceptibility of the cells to MAC-mediated damage, suggesting a role for this molecule in the protection of spermatozoa from complement-mediated damage in the female reproductive tract. Images Figure 2 Figure 4 PMID:1374057

  2. Analyzing the effect of routing protocols on media access control protocols in radio networks

    SciTech Connect

    Barrett, C. L.; Drozda, M.; Marathe, A.; Marathe, M. V.

    2002-01-01

    We study the effect of routing protocols on the performance of media access control (MAC) protocols in wireless radio networks. Three well known MAC protocols: 802.11, CSMA, and MACA are considered. Similarly three recently proposed routing protocols: AODV, DSR and LAR scheme 1 are considered. The experimental analysis was carried out using GloMoSim: a tool for simulating wireless networks. The main focus of our experiments was to study how the routing protocols affect the performance of the MAC protocols when the underlying network and traffic parameters are varied. The performance of the protocols was measured w.r.t. five important parameters: (i) number of received packets, (ii) average latency of each packet, (iii) throughput (iv) long term fairness and (v) number of control packets at the MAC layer level. Our results show that combinations of routing and MAC protocols yield varying performance under varying network topology and traffic situations. The result has an important implication; no combination of routing protocol and MAC protocol is the best over all situations. Also, the performance analysis of protocols at a given level in the protocol stack needs to be studied not locally in isolation but as a part of the complete protocol stack. A novel aspect of our work is the use of statistical technique, ANOVA (Analysis of Variance) to characterize the effect of routing protocols on MAC protocols. This technique is of independent interest and can be utilized in several other simulation and empirical studies.

  3. High-Accuracy Compact MacCormack-Type Schemes for Computational Aeroacoustics

    NASA Technical Reports Server (NTRS)

    Hixon, R.; Turkel, E.

    1998-01-01

    Using MacCormack-type methods, a new class of highly accurate compact MacCormack-type schemes is derived which does not require a tridiagonal matrix inversion to obtain the spatial derivatives. Two examples are shown, and results of these schemes for three linear and nonlinear CAA Benchmark Problems are presented.

  4. A Meta-Analytic Review of the MacAndrew Alcoholism Scale.

    ERIC Educational Resources Information Center

    Cooper-Hakim, Amy; Viswesvaran, Chockalingam

    2002-01-01

    Using meta analysis, examined the predictive validity of scores on the MacAndrew Alcoholism Scale (C. MacAndrew, 1965). Compared results for 161 studies with results for 63 studies using cut scores. Discusses why the use of continuous measures rather than cut scores is recommended. (SLD)

  5. 42 CFR 423.2108 - MAC Actions when request for review is filed.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... indicates, or the MAC determines that applying the standard timeframe for making a decision may seriously... 42 Public Health 3 2010-10-01 2010-10-01 false MAC Actions when request for review is filed. 423.2108 Section 423.2108 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH...

  6. Geochemistry and petrography of the MacAlpine Hills lunar meteorites

    NASA Technical Reports Server (NTRS)

    Lindstrom, Marilyn M.; Mckay, David S.; Wentworth, Susan J.; Martinez, Rene R.; Mittlefehldt, David W.; Wang, Ming-Sheng; Lipschutz, Michael E.

    1991-01-01

    MacAlpine Hills 88104 and 88105, anorthositic lunar meteorites recovered form the same area in Antartica, are characterized. Petrographic studies show that MAC88104/5 is a polymict breccia dominated by impact melt clasts. It is better classified as a fragmental breccia than a regolith breccia. The bulk composition is ferroan and highly aluminous (Al2O3-28 percent).

  7. 78 FR 65541 - Federal Agricultural Mortgage Corporation Funding and Fiscal Affairs; Farmer Mac Liquidity...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-01

    ... perception of Farmer Mac. \\9\\ Id. III. History of This Rule The financial crisis in 2008 caused the FCA to... examining and regulating liquidity risk management. In the aftermath of the financial crisis in 2008, Farmer... the aftermath of the 2008 crisis.\\17\\ Proposed Sec. 652.40 would require Farmer Mac to retain...

  8. THE EFFECT OF TEMPERATURE ON THE GROWTH OF MYCOBACTERIUM AVIUM COMPLEX (MAC) ORGANISMS

    EPA Science Inventory

    MAC organisms are able to grow, persist, and colonize in water distribution systems and may amplify in hospital hot water systems. This study examined the response of MAC organisms (M. avium, M. intracellulare, and MX) to a range of temperatures commonly associated with drinking...

  9. Paradox applications integration ATP`s for MAC and mass balance programs

    SciTech Connect

    Russell, V.K.; Mullaney, J.E.

    1994-10-17

    The K Basins Materials Accounting (MAC) and Material Balance (MBA) database system were set up to run under one common applications program. This Acceptance Test Plan (ATP) describes how the code was to be tested to verify its correctness. The scope of the tests is minimal, since both MAC and MBA have already been tested in detail as stand-alone programs.

  10. 78 FR 65145 - Federal Agricultural Mortgage Corporation Funding and Fiscal Affairs; Farmer Mac Capital Planning

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-31

    ..., Annual Stress Test, 77 FR 62417 (October 15, 2012); the OCC's final rule, Annual Stress Test, 77 FR 61238 (October 12, 2012); and the FHFA's proposed rule, Stress Testing of Regulated Entities, 77 FR 60948... distributions before making them. \\1\\ 78 FR 5320. II. Background A. Farmer Mac Farmer Mac is an institution...

  11. Truman's Firing of General Douglas MacArthur during the Korean War.

    ERIC Educational Resources Information Center

    Patterson, Amy; Schamel, Wynell; Potter Lee Ann

    2000-01-01

    Provides background information on the events that led up to President Harry S. Truman firing General Douglas MacArthur during the Korean War. Includes a copy of the document dismissing MacArthur from his position. Includes teaching activities corresponding to this event in history. (CMK)

  12. Quantitation of intracellular Mac-1 (CD11b/CD18) pools in human neutrophils.

    PubMed

    Jones, D H; Anderson, D C; Burr, B L; Rudloff, H E; Smith, C W; Krater, S S; Schmalstieg, F C

    1988-12-01

    The adhesive glycoprotein Mac-1 (CD11b/CD18) of the CD11/CD18 complex contributes to multiple neutrophil inflammatory functions. Activation of neutrophils by chemotactic stimuli results in a rapid, protein synthesis-independent increase in surface Mac-1 derived from incompletely defined intracellular compartments. Therefore, we developed a novel quantitative lectin immunoblot technique to define intracellular pools of Mac-1 in subcellular neutrophil fractions resolved on discontinuous Percoll gradients. In cavitates of unstimulated neutrophils, 30% and 26% of total Mac-1 was identified in beta [1.10 gm/ml; vitamin B12 binding protein (vit B12 B.P.)-rich] or pre-gamma (1.07 gm/ml; vit B12 B.P.-poor) granular fractions, respectively, whereas 24% was associated with the plasma membrane-rich gamma (1.06 gm/ml) fractions. N-formyl-methionyl-leucyl-phenylalanine (fMLP) stimulation (10(-8) M, 15 min, 37 degrees C) significantly diminished Mac-1 in pre-gamma (-18% of total, P less than 0.05) but not beta fractions (+6% of total). Under these conditions, the content of Mac-1 in gamma fractions increased 13% in association with four- to eightfold increase in surface Mac-1 expression (OKM-1 binding). These findings suggest that chemotactic stimuli increase plasma membrane and/or surface Mac-1 on human neutrophils by mobilizing a novel intracellular granule pool. PMID:2903896

  13. Self-Admitted Pretensions of Mac Users on a Predominantly PC University Campus

    ERIC Educational Resources Information Center

    Firmin, Michael W.; Wood, Whitney L. Muhlenkamp; Firmin, Ruth L.; Wood, Jordan C.

    2010-01-01

    The present qualitative research study addressed the overall research question of college students' pretention dynamics in the context of a university setting. Thirty-five Mac users were interviewed on a university campus that exclusively supports PC machines. Mac users shared four self-admitted pretensions related to using Macintosh computers.…

  14. Segmented proportional spacing medium access control protocol for APONs

    NASA Astrophysics Data System (ADS)

    Wang, Hongbin; Yu, Yiqing; Zhou, Dongru; Meng, Bo

    2004-04-01

    Combining asynchronous transfer mode (ATM) over a passive optical network (APON) can provide broadband services as defined by the international telecommunications union (ITU). The medium access control (MAC) layer is of primary importance to the access scheme as in controls the flow of traffic in the access network. This paper presents a novel MAC protocol-segmented proportional spacing MAC protocol, which complies with ITU-T recommendations, is firstly designed for APON system based on the analysis of different type of bandwidth allocation algorithms. The main idea of protocol is: frame structure adopts the structure regulated by ITU; fine time division for the optical network unit (ONU) to apply bandwidth; the bandwidth"s application is not based on the T-interface but ONU, the bandwidth allocation algorithm uses segmented proportional spacing algorithm. At last, we compare our protocol to other MAC protocols, the results show that proportional spacing and segmented bandwidth allocation control the cell jitter with satisfactory and improve the system bandwidth efficiency at same time, the correlative conclusions are given finally.

  15. RFI channels

    NASA Technical Reports Server (NTRS)

    Mceliece, R. J.

    1980-01-01

    A class of channel models is presented which exhibit varying burst error severity much like channels encountered in practice. An information-theoretic analysis of these channel models is made, and conclusions are drawn that may aid in the design of coded communication systems for realistic noisy channels.

  16. Synchronization strategies for RFI channels

    NASA Technical Reports Server (NTRS)

    Mceliece, R. J.; Vantilborg, H.; Tung, S.

    1977-01-01

    An RFI channel to be a multiple-access channel is defined in which no sender can know when any other starts, and the problem of determining the relative phases of the senders at the receiver is studied. A new result is proved about binary DEBruijn sequences.

  17. Opportunistic Pathogens Mycobacterium Avium Complex (MAC) and Legionella spp. Colonise Model Shower

    PubMed Central

    Whiley, Harriet; Giglio, Steven; Bentham, Richard

    2015-01-01

    Legionella spp. and Mycobacterium avium complex (MAC) are opportunistic pathogens of public health concern. Hot water systems, including showers, have been identified as a potential source of infection. This paper describes the colonization of Legionella and MAC on the flexible tubing within a model potable shower system, utilizing thermostatic mixing and a flexible shower head. A MAC qPCR method of enumeration was also developed. MAC and Legionella spp. were detected within the biofilm at maximum concentrations of 7.0 × 104 and 2.0 × 103 copies/cm2 PVC tubing respectively. No significant changes were observed between sample of the flexible shower tubing that dried between uses and those that remained filled with water. This suggested the “unhooking” showerheads and allowing them to dry is not an effective method to reduce the risk of Legionella or MAC colonisation. PMID:26213977

  18. Research on low-latency MAC protocols for wireless sensor networks

    NASA Astrophysics Data System (ADS)

    He, Chenguang; Sha, Xuejun; Lee, Chankil

    2007-11-01

    Energy-efficient should not be the only design goal in MAC protocols for wireless sensor networks, which involve the use of battery-operated computing and sensing devices. Low-latency operation becomes the same important as energy-efficient in the case that the traffic load is very heavy or the real-time constrain is used in applications like tracking or locating. This paper introduces some causes of traditional time delays which are inherent in a multi-hops network using existing WSN MAC protocols, illuminates the importance of low-latency MAC design for wireless sensor networks, and presents three MACs as examples of low-latency protocols designed specially for sleep delay, wait delay and wakeup delay in wireless sensor networks, respectively. The paper also discusses design trade-offs with emphasis on low-latency and points out their advantages and disadvantages, together with some design considerations and suggestions for MAC protocols for future applications and researches.

  19. Low-power low-latency MAC protocol for aeronautical applications

    NASA Astrophysics Data System (ADS)

    Sabater, Jordi; Kluge, Martin; Bovelli, Sergio; Schalk, Josef

    2007-05-01

    This paper describes asynchronous MAC (Medium Access Control) strategies based on the IEEE 802.15.4 physical layer for wireless aeronautical applications where low power and low latency are important requirements as well as security and data integrity. Sensor data is acquired and collected on request, by means of a mobile device, and later stored in a centralized database. In order to have the smallest power consumption the wireless sensor has to remain in deep sleep mode as long as possible and wake up and listen periodically for RF activity. If its unique ID is mentioned in the destination address field, the complete frame is received, processed and replied if necessary. If the detected packet is addressed to another sensor the reception will stop immediately and the wireless sensor will go into deep sleep mode again. Listening instead of sending actively does not 'pollute' the already crowded 2.45GHz spectrum, reduces collisions and increases security. The mobile data concentrator can not be synchronized with all the sensors installed in a distributed environment, therefore smart asynchronous data transmission strategies are needed to reduce latencies and increase throughput. For the considered application, sensors are independent of each other, simply share the medium and together with the data concentrator are organized in a star network topology. The centre of the star is the concentrator which is rarely in range. It coordinates and activates the wireless sensor nodes to collect the measured data.

  20. PHY and MAC Layer Design of Hybrid Spread Spectrum Based Smart Meter Network

    SciTech Connect

    Kuruganti, Phani Teja

    2012-01-01

    The smart grid is a combined process of revitalizing the traditional power grid applications and introducing new applications to improve the efficiency of power generation, transmission and distribution. This can be achieved by leveraging advanced communication and networking technologies. Therefore the selection of the appropriate communication technology for different smart grid applications has been debated a lot in the recent past. After comparing different possible technologies, a recent research study has arrived at a conclusion that the 3G cellular technology is the right choice for distribution side smart grid applications like smart metering, advanced distribution automation and demand response management system. In this paper, we argue that the current 3G/4G cellular technologies are not an appropriate choice for smart grid distribution applications and propose a Hybrid Spread Spectrum (HSS) based Advanced Metering Infrastructure (AMI) as one of the alternatives to 3G/4G technologies. We present a preliminary PHY and MAC layer design of a HSS based AMI network and evaluate their performance using matlab and NS2 simulations. Also, we propose a time hierarchical scheme that can significantly reduce the volume of random access traffic generated during blackouts and the delay in power outage reporting.

  1. Chondrocyte channel transcriptomics

    PubMed Central

    Lewis, Rebecca; May, Hannah; Mobasheri, Ali; Barrett-Jolley, Richard

    2013-01-01

    To date, a range of ion channels have been identified in chondrocytes using a number of different techniques, predominantly electrophysiological and/or biomolecular; each of these has its advantages and disadvantages. Here we aim to compare and contrast the data available from biophysical and microarray experiments. This letter analyses recent transcriptomics datasets from chondrocytes, accessible from the European Bioinformatics Institute (EBI). We discuss whether such bioinformatic analysis of microarray datasets can potentially accelerate identification and discovery of ion channels in chondrocytes. The ion channels which appear most frequently across these microarray datasets are discussed, along with their possible functions. We discuss whether functional or protein data exist which support the microarray data. A microarray experiment comparing gene expression in osteoarthritis and healthy cartilage is also discussed and we verify the differential expression of 2 of these genes, namely the genes encoding large calcium-activated potassium (BK) and aquaporin channels. PMID:23995703

  2. The Relationship of MacAndrew Alcoholism Scale Scores to MMPI Profile Type and Degree of Elevation.

    ERIC Educational Resources Information Center

    Pfost, Karen S.; And Others

    1984-01-01

    Investigated the relationship of the MacAndrew Alcoholism Scale (MAC) to personality type and level of emotional distress using Minnesota Multiphasic Personality Inventory scores of 38 alcoholic males. No relationship was found between the MAC and magnitude of psychological distress, as measured by T scores. (JAC)

  3. A Cross-Layer Duty Cycle MAC Protocol Supporting a Pipeline Feature for Wireless Sensor Networks

    PubMed Central

    Tong, Fei; Xie, Rong; Shu, Lei; Kim, Young-Chon

    2011-01-01

    Although the conventional duty cycle MAC protocols for Wireless Sensor Networks (WSNs) such as RMAC perform well in terms of saving energy and reducing end-to-end delivery latency, they were designed independently and require an extra routing protocol in the network layer to provide path information for the MAC layer. In this paper, we propose a new cross-layer duty cycle MAC protocol with data forwarding supporting a pipeline feature (P-MAC) for WSNs. P-MAC first divides the whole network into many grades around the sink. Each node identifies its grade according to its logical hop distance to the sink and simultaneously establishes a sleep/wakeup schedule using the grade information. Those nodes in the same grade keep the same schedule, which is staggered with the schedule of the nodes in the adjacent grade. Then a variation of the RTS/CTS handshake mechanism is used to forward data continuously in a pipeline fashion from the higher grade to the lower grade nodes and finally to the sink. No extra routing overhead is needed, thus increasing the network scalability while maintaining the superiority of duty-cycling. The simulation results in OPNET show that P-MAC has better performance than S-MAC and RMAC in terms of packet delivery latency and energy efficiency. PMID:22163895

  4. McMAC: Towards a MAC Protocol with Multi-Constrained QoS Provisioning for Diverse Traffic in Wireless Body Area Networks

    PubMed Central

    Monowar, Muhammad Mostafa; Hassan, Mohammad Mehedi; Bajaber, Fuad; Al-Hussein, Musaed; Alamri, Atif

    2012-01-01

    The emergence of heterogeneous applications with diverse requirements for resource-constrained Wireless Body Area Networks (WBANs) poses significant challenges for provisioning Quality of Service (QoS) with multi-constraints (delay and reliability) while preserving energy efficiency. To address such challenges, this paper proposes McMAC, a MAC protocol with multi-constrained QoS provisioning for diverse traffic classes in WBANs. McMAC classifies traffic based on their multi-constrained QoS demands and introduces a novel superframe structure based on the “transmit-whenever-appropriate” principle, which allows diverse periods for diverse traffic classes according to their respective QoS requirements. Furthermore, a novel emergency packet handling mechanism is proposed to ensure packet delivery with the least possible delay and the highest reliability. McMAC is also modeled analytically, and extensive simulations were performed to evaluate its performance. The results reveal that McMAC achieves the desired delay and reliability guarantee according to the requirements of a particular traffic class while achieving energy efficiency. PMID:23202224

  5. A Dynamic CFP Allocation and Opportunity Contention-Based WBAN MAC Protocol

    NASA Astrophysics Data System (ADS)

    Seo, Young-Sun; Kim, Dae-Young; Cho, Jinsung

    WBANs provide communication services in the vicinity of the human body. Since WBANs utilize both MICS frequency band for implant medical applications and ISM frequency band for medical and consumer electronics (CE) applications, MAC protocols in WBAN should be designed considering flexibility between medical and CE applications. In this letter, we identify the requirements of WBAN MAC protocols and propose a WBAN MAC protocol which satisfies the requirements. In order to provide transmission flexibility for various applications, we present the dynamic CFP allocation and opportunity period. Extensive simulation results show that the proposed protocol achieves improved throughput and latency in WBAN environment compared with IEEE 802.15.4.

  6. MAC Version 3.2, MBA Version 1.3 acceptance test summary report

    SciTech Connect

    Russell, V.K.

    1994-11-02

    The K Basins Materials Accounting (MAC) and Materials Balance (MBA) programs had the Paradox Conversion to 4.0 ATP run to check out the systems. This report describes the results of the test and provides the signoff sheets associated with the testing. The test primarily concentrated on verifying that MAC and MBA software would run properly in the Paradox 4.0 environment. Changes in the MAC and MBA programs were basically limited to superficial items needed to accommodate the enhanced method of execution.

  7. TRP Channels

    PubMed Central

    Venkatachalam, Kartik; Montell, Craig

    2011-01-01

    The TRP (Transient Receptor Potential) superfamily of cation channels is remarkable in that it displays greater diversity in activation mechanisms and selectivities than any other group of ion channels. The domain organizations of some TRP proteins are also unusual, as they consist of linked channel and enzyme domains. A unifying theme in this group is that TRP proteins play critical roles in sensory physiology, which include contributions to vision, taste, olfaction, hearing, touch, and thermo- and osmosensation. In addition, TRP channels enable individual cells to sense changes in their local environment. Many TRP channels are activated by a variety of different stimuli and function as signal integrators. The TRP superfamily is divided into seven subfamilies: the five group 1 TRPs (TRPC, TRPV, TRPM, TRPN, and TRPA) and two group 2 subfamilies (TRPP and TRPML). TRP channels are important for human health as mutations in at least four TRP channels underlie disease. PMID:17579562

  8. History of the paired lunar meteorites MAC88104 and MAC88105 derived from noble gas isotopes, radionuclides, and some chemical abundances

    SciTech Connect

    Eugster, O.; Burger, M.; Kraehenbuehl, U.; Michel, T. ); Beer, J. ); Finkel, R.C. ); Hofmann, H.J.; Synal, H.A.; Woelfli, W. )

    1991-11-01

    Noble gas isotopes, radionuclides, and chemical abundances were studied in the lunar meteorites MAC88104 and MAC88105 collected in the MacAlpine Hills area of Antarctica. The concentrations of the noble gas isotopes and the radionuclide activities in the two meteorites are essentially identical, proving that the two meteorites are paired. From {sup 40}K-{sup 40}Ar dating the authors obtain a gas retention age of 3,550 {plus minus} 400 Ma, typical for lunar surface material. Probably before breccia compaction the MAC88104/5 material resided for 630 {plus minus} 200 Ma at an average shielding depth of 85 g/cm{sup 2}, that is, about 50 cm below the lunar surface in the lunar regolith, as judged from the concentration of cosmic-ray produced Kr and Xe isotopes. Although this duration of lunar regolith residence is relatively long, MAC88104/5 represent immature regolith material: the concentration of solar wind implanted noble gases are two orders of magnitude lower than those in mature lunar soil. The {sup 40}Ar/{sup 36}Ar ratio of the trapped component is 5.7 {plus minus} 1.0, indicating an intermediate antiquity of the material; the authors estimate that the solar wind and lunar atmospheric particles were implanted about 2,000 Ma ago. The radionuclide activities allow a determination of the exposure history of the MAC88104/5 material. The duration of the Moon-Earth transfer was {much lt} 0.24 Ma. The exposure histories of the lunar meteorites discussed in this work indicate that at least two impact events are required for their ejection from the Moon. The authors first noble gas results for lunar meteorite Yamato-793274 show that it represents mature lunar regolith material with relatively high concentrations of solar wind implanted noble gas and a duration of several hundred million years of exposure to cosmic rays.

  9. 42 CFR 423.2122 - What evidence may be submitted to the MAC.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., the MAC may request the Secretary to seek enforcement of the subpoena in accordance with section 205(e) of the Act, 42 U.S.C. 405(e). (2) After submitting the enforcement request, the time period for...

  10. DETECTION,QUANTIFICATION AND CHARACTERIZATION OF MYCOBACTERIUM AVIUM COMPLEX (MAC) ORGANISMS IN DRINKING WATER.

    EPA Science Inventory

    Bacteria belonging to the Mycobacterium avium complex (MAC), including Mycobacterium avium and M. intracellulare, are clinically relevant and cause a myriad of opportunistic infections. Children, the elderly, and persons with previous lung conditions or immune system dysfunction...

  11. 7. Historic American Buildings Survey, Richard MacAllister, Photographer May 29, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Historic American Buildings Survey, Richard MacAllister, Photographer May 29, 1936 DETAIL OF STAIR (SOUTH ELEVATION). - Rode-Kothe House, East of U.S. 87 at Cherry Spring, Cherry Spring, Gillespie County, TX

  12. 2. Historic American Buildings Survey, Richard MacAllister, Photographer May 29, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Historic American Buildings Survey, Richard MacAllister, Photographer May 29, 1936 SOUTH ELEVATION (FRONT). - Rode-Kothe House, East of U.S. 87 at Cherry Spring, Cherry Spring, Gillespie County, TX

  13. 6. Historic American Buildings Survey, Richard MacAllister, Photographer May 29, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Historic American Buildings Survey, Richard MacAllister, Photographer May 29, 1936 DETAIL OF STAIR, DOOR AND COLUMNS (SOUTH ELEVATION). - Rode-Kothe House, East of U.S. 87 at Cherry Spring, Cherry Spring, Gillespie County, TX

  14. 8. Historic American Buildings Survey, Richard MacAllister, Photographer May 29, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Historic American Buildings Survey, Richard MacAllister, Photographer May 29, 1936 INSIDE STAIR (LOOKING SOUTH). - Rode-Kothe House, East of U.S. 87 at Cherry Spring, Cherry Spring, Gillespie County, TX

  15. Industrial WSN Based on IR-UWB and a Low-Latency MAC Protocol

    NASA Astrophysics Data System (ADS)

    Reinhold, Rafael; Underberg, Lisa; Wulf, Armin; Kays, Ruediger

    2016-07-01

    Wireless sensor networks for industrial communication require high reliability and low latency. As current wireless sensor networks do not entirely meet these requirements, novel system approaches need to be developed. Since ultra wideband communication systems seem to be a promising approach, this paper evaluates the performance of the IEEE 802.15.4 impulse-radio ultra-wideband physical layer and the IEEE 802.15.4 Low Latency Deterministic Network (LLDN) MAC for industrial applications. Novel approaches and system adaptions are proposed to meet the application requirements. In this regard, a synchronization approach based on circular average magnitude difference functions (CAMDF) and on a clean template (CT) is presented for the correlation receiver. An adapted MAC protocol titled aggregated low latency (ALL) MAC is proposed to significantly reduce the resulting latency. Based on the system proposals, a hardware prototype has been developed, which proves the feasibility of the system and visualizes the real-time performance of the MAC protocol.

  16. 12. Historic American Buildings Survey, E.P. MacFarland, Photographer October 1936, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Historic American Buildings Survey, E.P. MacFarland, Photographer October 1936, MANTEL - SOUTH WEST CORNER OF NORTH WEST ROOM. - Judge Teunis Schenck House, Highland Park, Jamaica Avenue, Brooklyn, Kings County, NY

  17. 6. Historic American Buildings Survey, E.P. MacFarland, Photographer October 1936, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Historic American Buildings Survey, E.P. MacFarland, Photographer October 1936, DETAIL EXTERIOR SOUTH EAST CORNER. - Judge Teunis Schenck House, Highland Park, Jamaica Avenue, Brooklyn, Kings County, NY

  18. 17. Historic American Buildings Survey, E.P. MacFarland, Photographer October 1936, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. Historic American Buildings Survey, E.P. MacFarland, Photographer October 1936, FRAMING DETAIL (SECOND FLOOR) TOWARD NORTH SIDE. - Judge Teunis Schenck House, Highland Park, Jamaica Avenue, Brooklyn, Kings County, NY

  19. 8. Historic American Buildings Survey, E.P. MacFarland, Photographer October 1936, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Historic American Buildings Survey, E.P. MacFarland, Photographer October 1936, INTERIOR DETAIL MAIN ENTRANCE. - Judge Teunis Schenck House, Highland Park, Jamaica Avenue, Brooklyn, Kings County, NY

  20. 14. Historic American Buildings Survey, E.P. MacFarland, Photographer October 1936, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Historic American Buildings Survey, E.P. MacFarland, Photographer October 1936, FRAMING DETAIL (SECOND FLOOR) NORTH EAST CORNER. - Judge Teunis Schenck House, Highland Park, Jamaica Avenue, Brooklyn, Kings County, NY

  1. 15. Historic American Buildings Survey, E.P. MacFarland, Photographer October 1936, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. Historic American Buildings Survey, E.P. MacFarland, Photographer October 1936, DETAIL FRAMING (SECOND FLOOR) UPRIGHT AND PURLIN. - Judge Teunis Schenck House, Highland Park, Jamaica Avenue, Brooklyn, Kings County, NY

  2. 7. Historic American Buildings Survey, E.P. MacFarland, Photographer October 1936, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Historic American Buildings Survey, E.P. MacFarland, Photographer October 1936, DETAIL ENTRANCE SOUTH ELEVATION. - Judge Teunis Schenck House, Highland Park, Jamaica Avenue, Brooklyn, Kings County, NY

  3. 11. Historic American Buildings Survey, E.P. MacFarland, Photographer October 1936, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Historic American Buildings Survey, E.P. MacFarland, Photographer October 1936, MANTEL - NORTH WEST CORNER OF SOUTH WEST ROOM. - Judge Teunis Schenck House, Highland Park, Jamaica Avenue, Brooklyn, Kings County, NY

  4. 16. Historic American Buildings Survey, E.P. MacFarland, Photographer October 1936, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. Historic American Buildings Survey, E.P. MacFarland, Photographer October 1936, VIEW OF ATTIC (SECOND FLOOR) TOWARD WEST. - Judge Teunis Schenck House, Highland Park, Jamaica Avenue, Brooklyn, Kings County, NY

  5. BIG MAC: A bolometer array for mid-infrared astronomy, Center Director's Discretionary Fund

    NASA Technical Reports Server (NTRS)

    Telesco, C. M.; Decher, R.; Baugher, C.

    1985-01-01

    The infrared array referred to as Big Mac (for Marshall Array Camera), was designed for ground based astronomical observations in the wavelength range 5 to 35 microns. It contains 20 discrete gallium-doped germanium bolometer detectors at a temperature of 1.4K. Each bolometer is irradiated by a square field mirror constituting a single pixel of the array. The mirrors are arranged contiguously in four columns and five rows, thus defining the array configuration. Big Mac utilized cold reimaging optics and an up looking dewar. The total Big Mac system also contains a telescope interface tube for mounting the dewar and a computer for data acquisition and processing. Initial astronomical observations at a major infrared observatory indicate that Big Mac performance is excellent, having achieved the design specifications and making this instrument an outstanding tool for astrophysics.

  6. 16. Photocopy of drawing (location of original unknown) MacDonald and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. Photocopy of drawing (location of original unknown) MacDonald and Applegarth, Architects, April 1912 SUTTER STREET ELEVATION - Holbrook Building, 58 Sutter Street, San Francisco, San Francisco County, CA

  7. Conversion to Paradox 4.02 ATP`s for MAC and mass balance programs

    SciTech Connect

    Russell, V.K.

    1994-10-17

    The K Basins Materials Accounting (MAC) and Material Balance (MBA) database system were converted from Paradox 3.5 to Paradox 4.0. The ATP describes how the code was to be tested to verify its corrections.

  8. Evaluation of video transmission of MAC protocols in wireless sensor network

    NASA Astrophysics Data System (ADS)

    Maulidin, Mahmuddin, M.; Kamaruddin, L. M.; Elsaikh, Mohamed

    2016-08-01

    Wireless Sensor Network (WSN) is a wireless network which consists of sensor nodes scattered in a particular area which are used to monitor physical or environment condition. Each node in WSN is also scattered in sensor field, so an appropriate scheme of MAC protocol should have to develop communication link for data transferring. Video transmission is one of the important applications for the future that can be transmitted with low aspect in side of cost and also power consumption. In this paper, comparison of five different MAC WSN protocol for video transmission namely IEEE 802.11 standard, IEEE 802.15.4 standard, CSMA/CA, Berkeley-MAC, and Lightweight-MAC protocol are studied. Simulation experiment has been conducted in OMNeT++ with INET network simulator software to evaluate the performance. Obtained results indicate that IEEE 802.11 works better than other protocol in term of packet delivery, throughput, and latency.

  9. MAC Version 3.3, MBA Version 1.3 acceptance test summary report

    SciTech Connect

    Russell, V.K.

    1994-11-02

    The K Basins Materials Accounting (MAC) and Materials Balance (MBA) programs had the Paradox Code Cleanup ATP run to check out the systems. This report describes the results of the test and provides the signoff sheets associated with the testing. The Acceptance Test results indicate that the MAC and MBA systems are ready for operation using the cleaned up code. The final codes were removed to the production space on the customer server on April 15th.

  10. STS-52 Payload Specialist MacLean floats in pool during JSC bailout exercises

    NASA Technical Reports Server (NTRS)

    1992-01-01

    STS-52 Columbia, Orbiter Vehicle (OV) 102, Payload Specialist Steven G. MacLean, wearing launch and entry suit (LES) and clamshell helmet, is assisted by SCUBA-equipped divers as he floats in pool during emergency egress (bailout) training exercises in JSC's Weightless Environment Training Facility Bldg 29. Bailout exercises utilize the WETF's 25-foot deep pool as the ocean during this water landing simulation. MacLean represents the Canadian Space Agency (CSA).

  11. Considerations for Improving the Capacity and Performance of AeroMACS

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.; Kamali, Behnam; Apaza, Rafael D.; Wilson, Jeffrey D.; Dimond, Robert P.

    2014-01-01

    The Aeronautical Mobile Airport Communications System (AeroMACS) has progressed from concept through prototype development, testing, and standards development and is now poised for the first operational deployments at nine US airports by the Federal Aviation Administration. These initial deployments will support fixed applications. Mobile applications providing connectivity to and from aircraft and ground-based vehicles on the airport surface will occur at some point in the future. Given that many fixed applications are possible for AeroMACS, it is necessary to now consider whether the existing capacity of AeroMACS will be reached even before the mobile applications are ready to be added, since AeroMACS is constrained by both available bandwidth and transmit power limitations. This paper describes some concepts that may be applied to improve the future capacity of AeroMACS, with a particular emphasis on gains that can be derived from the addition of IEEE 802.16j multihop relays to the AeroMACS standard, where a significant analysis effort has been undertaken.

  12. [The Nobel Prize in Chemistry 2003 awarded for discoveries concerning molecular channels in cell membranes].

    PubMed

    Dijkstra, C D

    2003-12-27

    About 70% of the human body consists of salt water. The Nobel Prize 2003 in Chemistry rewards Peter Agre for the discovery of water channels and Roderick MacKinnon for structural and mechanistic studies of ion channels. Their studies have demonstrated how ions and water are transported through cell membranes. This transport is essential for the regulation of size and osmotic pressure in cells and organelles and it plays a major role in salt and water homoeostasis and in the generation of electrical signals in nerve cells. Agre succeeded in isolating a membrane protein which later studies revealed to be a long-postulated water channel, MacKinnon succeeded in determining the spatial structure of a potassium channel. PMID:14723023

  13. Web Accessibility and Accessibility Instruction

    ERIC Educational Resources Information Center

    Green, Ravonne A.; Huprich, Julia

    2009-01-01

    Section 508 of the Americans with Disabilities Act (ADA) mandates that programs and services be accessible to people with disabilities. While schools of library and information science (SLIS*) and university libraries should model accessible Web sites, this may not be the case. This article examines previous studies about the Web accessibility of…

  14. Validation of Chinese version of the MacArthur Competence Assessment Tool for Clinical Research (MacCAT-CR) in patients with schizophrenia spectrum disorders.

    PubMed

    Lan, Tsuo-Hung; Wu, Bo-Jian; Chen, Hsing-Kang; Liao, Hsun-Yi; Lee, Shin-Min; Sun, Hsiao-Ju

    2013-12-15

    There is a lack of validated instruments assessing the decision-making capacity to consent to clinical research of patients with schizophrenia spectrum disorders who speak Chinese. This study aimed to determine the validity and reliability of the Chinese version of MacArthur Competence Assessment Tool for Clinical Research (MacCAT-CR). The MacCAT-CR using a hypothetical study, the Positive and Negative Syndrome Scale (PANSS), the Mini-Mental State Examination (MMSE) assessed 139 patients with schizophrenia or schizoaffective disorder. The Cronbach's alpha coefficient was 0.74. The intra-class coefficients for understanding, appreciation, and reasoning scores ranged from 0.53 to 0.81. Regarding validity, the understanding, appreciation and reasoning scores were negatively correlated with the PANSS (r ranged from -0.27 to -0.33), and the negative subscale score (r ranged from -0.31 to -0.37) as well as positively correlated with the MMSE (r ranged from 0.26 to 0.43). All pvalues were less than 0.01. The factor analysis explained 57.6 % of the total variance; specifically, Components 1 and 2 contributed 44.5% and 13.1 % of the variance respectively. These findings indicate that the Chinese version of the MacCAT-CR is a reliable and valid instrument to assess the decision-making capacity to consent to clinical research of patients with schizophrenia spectrum disorders. PMID:23928212

  15. Advertisement-Based Energy Efficient Medium Access Protocols for Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Ray, Surjya Sarathi

    One of the main challenges that prevents the large-scale deployment of Wireless Sensor Networks (WSNs) is providing the applications with the required quality of service (QoS) given the sensor nodes' limited energy supplies. WSNs are an important tool in supporting applications ranging from environmental and industrial monitoring, to battlefield surveillance and traffic control, among others. Most of these applications require sensors to function for long periods of time without human intervention and without battery replacement. Therefore, energy conservation is one of the main goals for protocols for WSNs. Energy conservation can be performed in different layers of the protocol stack. In particular, as the medium access control (MAC) layer can access and control the radio directly, large energy savings is possible through intelligent MAC protocol design. To maximize the network lifetime, MAC protocols for WSNs aim to minimize idle listening of the sensor nodes, packet collisions, and overhearing. Several approaches such as duty cycling and low power listening have been proposed at the MAC layer to achieve energy efficiency. In this thesis, I explore the possibility of further energy savings through the advertisement of data packets in the MAC layer. In the first part of my research, I propose Advertisement-MAC or ADV-MAC, a new MAC protocol for WSNs that utilizes the concept of advertising for data contention. This technique lets nodes listen dynamically to any desired transmission and sleep during transmissions not of interest. This minimizes the energy lost in idle listening and overhearing while maintaining an adaptive duty cycle to handle variable loads. Additionally, ADV-MAC enables energy efficient MAC-level multicasting. An analytical model for the packet delivery ratio and the energy consumption of the protocol is also proposed. The analytical model is verified with simulations and is used to choose an optimal value of the advertisement period

  16. Advertisement-Based Energy Efficient Medium Access Protocols for Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Ray, Surjya Sarathi

    One of the main challenges that prevents the large-scale deployment of Wireless Sensor Networks (WSNs) is providing the applications with the required quality of service (QoS) given the sensor nodes' limited energy supplies. WSNs are an important tool in supporting applications ranging from environmental and industrial monitoring, to battlefield surveillance and traffic control, among others. Most of these applications require sensors to function for long periods of time without human intervention and without battery replacement. Therefore, energy conservation is one of the main goals for protocols for WSNs. Energy conservation can be performed in different layers of the protocol stack. In particular, as the medium access control (MAC) layer can access and control the radio directly, large energy savings is possible through intelligent MAC protocol design. To maximize the network lifetime, MAC protocols for WSNs aim to minimize idle listening of the sensor nodes, packet collisions, and overhearing. Several approaches such as duty cycling and low power listening have been proposed at the MAC layer to achieve energy efficiency. In this thesis, I explore the possibility of further energy savings through the advertisement of data packets in the MAC layer. In the first part of my research, I propose Advertisement-MAC or ADV-MAC, a new MAC protocol for WSNs that utilizes the concept of advertising for data contention. This technique lets nodes listen dynamically to any desired transmission and sleep during transmissions not of interest. This minimizes the energy lost in idle listening and overhearing while maintaining an adaptive duty cycle to handle variable loads. Additionally, ADV-MAC enables energy efficient MAC-level multicasting. An analytical model for the packet delivery ratio and the energy consumption of the protocol is also proposed. The analytical model is verified with simulations and is used to choose an optimal value of the advertisement period

  17. The first/last access protocol

    NASA Astrophysics Data System (ADS)

    Karol, M. J.; Schwartz, S. C.

    When a random access protocol is used to share a communications channel, conflicts arising from simultaneous transmissions must be resolved. Listening to feedback on a broadcast channel, and using knowledge of round trip propagation delays, the First/Last Access Protocol (FLAP) reserves time for retransmissions of the 'first' and 'last' packets involved in a channel collision. Time slots of duration greater than a packet transmission time exploit the advantages of both slotted access protocols. The maximum achievable system throughput is 0.673 as the input rate increases. Extensions of FLAP yield system throughputs greater than 0.80.

  18. Characterization of the Murine Myeloid Precursor Cell Line MuMac-E8

    PubMed Central

    Fricke, Stephan; Riemschneider, Sina; Kohlschmidt, Janine; Hilger, Nadja; Fueldner, Christiane; Knauer, Jens; Sack, Ulrich; Emmrich, Frank; Lehmann, Jörg

    2014-01-01

    Starting point for the present work was the assumption that the cell line MuMac-E8 represents a murine cell population with stem cell properties. Preliminary studies already pointed to the expression of stem-cell associated markers and a self-regenerative potential of the cells. The cell line MuMac-E8 should be examined for their differential stage within stem cell hierarchy. MuMac-E8 cells were derived from a chimeric mouse model of arthritis. It could be shown that MuMac-E8 cells express mRNA of some genes associated with pluripotent stem cells (Nanog, Nucleostemin), of genes for hematopoietic markers (EPCR, Sca-1, CD11b, CD45), for the mesenchymal marker CD105 and of genes for the neural markers Pax-6 and Ezrin. In methylcellulose and May-Grünwald-Giemsa staining, hematopoietic colonies were obtained but the hematopoietic system of lethally irradiated mice could not be rescued. Osteogenic differentiation was not detectable. Thus, it became evident that MuMac-E8 represents not a stem cell line. However, MuMac-E8 cells expressed several myeloid surface markers (i.e. CD11b, F4/80, CD14, CD64), showed phagocytosis and is capable of producing nitric oxide. Thus, this cell line seems to be arrested an advanced stage of myeloid differentiation. Adherence data measured by impedance-based real-time cell analysis together with cell morphology data suggested that MuMac-E8 represents a new macrophage precursor cell line exhibiting weak adherence. This cell line is suitable as an in-vitro model for testing of macrophage functions. Moreover, it might be also useful for differentiation or reprogramming studies. PMID:25546418

  19. Tests of executive functioning predict scores on the MacAndrew Alcoholism Scale.

    PubMed

    Deckel, A W

    1999-02-01

    1. Previous work reported that tests of executive functioning (EF) predict the risk of alcoholism in subject populations selected for a "high density" of a family history of alcoholism and/or the presence of sociopathic traits. The current experiment examined the ability of EF tests to predict the risk of alcoholism, as measured by the MacAndrew Alcoholism Scale (MAC), in outpatient subjects referred to a general neuropsychological testing service. 2. Sixty-eight male and female subjects referred for neuropsychological testing were assessed for their past drinking histories and administered the Wisconsin Card Sorting Test, the Wechsler Adult Intelligence Scale-Revised, the Trails (Part B) Test, and the MAC. Principal Components analysis (PCA) reduced the number of EF tests to two measures, including one that loaded on the WCST, and one that loaded on the Similarities, Picture Arrangement, and Trails tests. Multiple hierarchical regression first removed the variance from demographic variables, alcohol consumption, and verbal (i.e., Vocabulary) and non-verbal (i.e., Block Design) IQ, and then entered the executive functioning factors into the prediction of the MAC. 3. Seventy-six percent of the subjects were classified as either light, infrequent, or non-drinkers on the Quantity-Frequency-Variability scale. The factor derived from the WCST on PCA significantly added to the prediction of risk on the MAC (p = .0063), as did scores on Block Design (p = .033). Relatively more impaired scores on the WCST factor and Block Design were predictive of higher scores on the MAC. The other factors were not associated with MAC scores. 4. These results support the hypothesis that decrements in EF are associated with risk factors for alcoholism, even in populations where the density of alcoholic behaviors are not unusually high. When taken in conjunction with other findings, these results implicate EF test scores, and prefrontal brain functioning, in the neurobiology of the risk for

  20. MLKL forms cation channels

    PubMed Central

    Xia, Bingqing; Fang, Sui; Chen, Xueqin; Hu, Hong; Chen, Peiyuan; Wang, Huayi; Gao, Zhaobing

    2016-01-01

    The mixed lineage kinase domain-like (MLKL) protein is a key factor in tumor necrosis factor-induced necroptosis. Recent studies on necroptosis execution revealed a commitment role of MLKL in membrane disruption. However, our knowledge of how MLKL functions on membrane remains very limited. Here we demonstrate that MLKL forms cation channels that are permeable preferentially to Mg2+ rather than Ca2+ in the presence of Na+ and K+. Moreover, the N-terminal domain containing six helices (H1-H6) is sufficient to form channels. Using the substituted cysteine accessibility method, we further determine that helix H1, H2, H3, H5 and H6 are transmembrane segments, while H4 is located in the cytoplasm. Finally, MLKL-induced membrane depolarization and cell death exhibit a positive correlation to its channel activity. The Mg2+-preferred permeability and five transmembrane segment topology distinguish MLKL from previously identified Mg2+-permeable channels and thus establish MLKL as a novel class of cation channels. PMID:27033670

  1. The allocation of cargo to channel missions

    SciTech Connect

    Liu, Cheng; Harrison, G.

    1992-01-01

    Each month the armed services provide a forecast of tons of cargo by channel to MAC. The purpose of the Channels Allocation Algorithm is to allocate cargo requirements to specific Channel Missions. The objective of the allocation is algorithm is to minimize frequency and cargo requirements shortfall. The constraints on the allocation model include flying hours, channel frequencies, mission structure, mission operation days, and aircraft capacity. Cargo requirements shortfall is defined as the tonnage of cargo not moved from the airfields in the United States that are channel staging points to overseas locations. Channel frequencies are defined by the number of times a destination is served by an origin in one month. The mission structures are defined as sets of missions usually in the form of circuit. Mission operating days are determined by the operating day rules for the month, or they can be input by the user for an individual month. One of the assumptions in this model is that there is only one transshipment allowed between any origin and a destination if there is no mission that actually connects the stations. The transshipment stations are also restricted in that only certain stations can serve as transshipment stations. The Channels Allocation Algorithm consists of two linear programs that incorporate three objectives. The objectives are: (1) to minimize that number of frequency channels not met. (2) to minimize cargo shortfall, and (3) to minimize operating cost. The first linear program minimizes frequency channels not met, subject to the mission structure, number of times the mission operates, and total flying hours available. The second linear program minimizes the fleet operating cost cargo handling cost, and cargo shortfall, subject to frequency channels met by the first linear program, aircraft capacity, and total flying hours available. This document is comprised of viewgraphs.

  2. The allocation of cargo to channel missions

    SciTech Connect

    Liu, Cheng; Harrison, G.

    1992-06-01

    Each month the armed services provide a forecast of tons of cargo by channel to MAC. The purpose of the Channels Allocation Algorithm is to allocate cargo requirements to specific Channel Missions. The objective of the allocation is algorithm is to minimize frequency and cargo requirements shortfall. The constraints on the allocation model include flying hours, channel frequencies, mission structure, mission operation days, and aircraft capacity. Cargo requirements shortfall is defined as the tonnage of cargo not moved from the airfields in the United States that are channel staging points to overseas locations. Channel frequencies are defined by the number of times a destination is served by an origin in one month. The mission structures are defined as sets of missions usually in the form of circuit. Mission operating days are determined by the operating day rules for the month, or they can be input by the user for an individual month. One of the assumptions in this model is that there is only one transshipment allowed between any origin and a destination if there is no mission that actually connects the stations. The transshipment stations are also restricted in that only certain stations can serve as transshipment stations. The Channels Allocation Algorithm consists of two linear programs that incorporate three objectives. The objectives are: (1) to minimize that number of frequency channels not met. (2) to minimize cargo shortfall, and (3) to minimize operating cost. The first linear program minimizes frequency channels not met, subject to the mission structure, number of times the mission operates, and total flying hours available. The second linear program minimizes the fleet operating cost cargo handling cost, and cargo shortfall, subject to frequency channels met by the first linear program, aircraft capacity, and total flying hours available. This document is comprised of viewgraphs.

  3. Open Access

    ERIC Educational Resources Information Center

    Suber, Peter

    2012-01-01

    The Internet lets us share perfect copies of our work with a worldwide audience at virtually no cost. We take advantage of this revolutionary opportunity when we make our work "open access": digital, online, free of charge, and free of most copyright and licensing restrictions. Open access is made possible by the Internet and copyright-holder…

  4. Access Denied

    ERIC Educational Resources Information Center

    Villano, Matt

    2008-01-01

    Building access control (BAC)--a catchall phrase to describe the systems that control access to facilities across campus--has traditionally been handled with remarkably low-tech solutions: (1) manual locks; (2) electronic locks; and (3) ID cards with magnetic strips. Recent improvements have included smart cards and keyless solutions that make use…

  5. Detection of constitutive heterodimerization of the integrin Mac-1 subunits by fluorescence resonance energy transfer in living cells

    SciTech Connect

    Fu Guo; Yang Huayan; Wang Chen; Zhang Feng; You Zhendong; Wang Guiying; He Cheng; Chen Yizhang . E-mail: yzchen0928@yahoo.com; Xu Zhihan . E-mail: zzxu@mail.shcnc.ac.cn

    2006-08-04

    Macrophage differentiation antigen associated with complement three receptor function (Mac-1) belongs to {beta}{sub 2} subfamily of integrins that mediate important cell-cell and cell-extracellular matrix interactions. Biochemical studies have indicated that Mac-1 is a constitutive heterodimer in vitro. Here, we detected the heterodimerization of Mac-1 subunits in living cells by means of two fluorescence resonance energy transfer (FRET) techniques (fluorescence microscopy and fluorescence spectroscopy) and our results demonstrated that there is constitutive heterodimerization of the Mac-1 subunits and this constitutive heterodimerization of the Mac-1 subunits is cell-type independent. Through FRET imaging, we found that heterodimers of Mac-1 mainly localized in plasma membrane, perinuclear, and Golgi area in living cells. Furthermore, through analysis of the estimated physical distances between cyan fluorescent protein (CFP) and yellow fluorescent protein (YFP) fused to Mac-1 subunits, we suggested that the conformation of Mac-1 subunits is not affected by the fusion of CFP or YFP and inferred that Mac-1 subunits take different conformation when expressed in Chinese hamster ovary (CHO) and human embryonic kidney (HEK) 293T cells, respectively.

  6. Eliminating the Heart from the Curcumin Molecule: Monocarbonyl Curcumin Mimics (MACs)

    PubMed Central

    Shetty, Dinesh; Kim, Yong Joon; Shim, Hyunsuk; Snyder, James P.

    2015-01-01

    Curcumin is a natural product with several thousand years of heritage. Its traditional Asian application to human ailments has been subjected in recent decades to worldwide pharmacological, biochemical and clinical investigations. Curcumin’s Achilles heel lies in its poor aqueous solubility and rapid degradation at pH ~ 7.4. Researchers have sought to unlock curcumin’s assets by chemical manipulation. One class of molecules under scrutiny are the monocarbonyl analogs of curcumin (MACs). A thousand plus such agents have been created and tested primarily against cancer and inflammation. The outcome is clear. In vitro, MACs furnish a 10–20 fold potency gain vs. curcumin for numerous cancer cell lines and cellular proteins. Similarly, MACs have successfully demonstrated better pharmacokinetic (PK) profiles in mice and greater tumor regression in cancer xenografts in vivo than curcumin. The compounds reveal limited toxicity as measured by murine weight gain and histopathological assessment. To our knowledge, MAC members have not yet been monitored in larger animals or humans. However, Phase 1 clinical trials are certainly on the horizon. The present review focuses on the large and evolving body of work in cancer and inflammation, but also covers MAC structural diversity and early discovery for treatment of bacteria, tuberculosis, Alzheimer’s disease and malaria. PMID:25547726

  7. Crystallization and preliminary X-ray crystallographic analysis of MacA from Actinobacillus actinomycetemcomitans

    SciTech Connect

    Piao, Shunfu; Xu, Yongbin; Ha, Nam-Chul

    2008-05-01

    A periplasmic membrane-fusion protein MacA from Actinobacillus actinomycetemcomitans, an essential component of the multidrug efflux pump in Gram-negative bacteria, was crystallized. Periplasmic membrane-fusion proteins (MFPs) are an essential component of the multidrug efflux pump in Gram-negative bacteria. They play a crucial role in bridging the outer membrane porin TolC and two distinct types of inner membrane transporters. The MFP MacA bridges the inner membrane ABC-type multidrug transporter MacB and the outer membrane porin TolC. MacA from the pathogenic bacterium Actinobacillus actinomycetemcomitans was expressed in Escherichia coli B834 (DE3) and the recombinant protein was purified using Ni–NTA affinity, Q anion-exchange and gel-filtration chromatography. The purified MacA protein was crystallized using the vapour-diffusion method. A MAD diffraction data set was collected to a resolution of 3.0 Å at 100 K. The crystal belongs to space group P622, with unit-cell parameters a = b = 109.2, c = 255.4 Å, α = β = 90, γ = 120°, and contains one molecule in the asymmetric unit.

  8. MAP, MAC, and vortex-rings configurations in the Weinberg-Salam model

    NASA Astrophysics Data System (ADS)

    Teh, Rosy; Ng, Ban-Loong; Wong, Khai-Ming

    2015-11-01

    We report on the presence of new axially symmetric monopoles, antimonopoles and vortex-rings solutions of the SU(2)×U(1) Weinberg-Salam model of electromagnetic and weak interactions. When the ϕ-winding number n = 1, and 2, the configurations are monopole-antimonopole pair (MAP) and monopole-antimonopole chain (MAC) with poles of alternating sign magnetic charge arranged along the z-axis. Vortex-rings start to appear from the MAP and MAC configurations when the winding number n = 3. The MAP configurations possess zero net magnetic charge whereas the MAC configurations possess net magnetic charge of 4 πn / e. In the MAP configurations, the monopole-antimonopole pair is bounded by the Z0 field flux string and there is an electromagnetic current loop encircling it. The monopole and antimonopole possess magnetic charges ± 4πn/e sin2θW respectively. In the MAC configurations there is no string connecting the monopole and the adjacent antimonopole and they possess magnetic charges ± 4 πn/e respectively. The MAC configurations possess infinite total energy and zero magnetic dipole moment whereas the MAP configurations which are actually sphalerons possess finite total energy and magnetic dipole moment. The configurations were investigated for varying values of Higgs self-coupling constant 0 ≤ λ ≤ 40 at Weinberg angle θW = π/4.

  9. A Study on Energy Efficient MAC Protocol of Wireless Sensor Network for Ubiquitous Agriculture

    NASA Astrophysics Data System (ADS)

    Lee, Ho-Chul; Lee, Ji-Woong; Hwang, Jeong-Hwan; Yoe, Hyun

    Various technologies are used in the agricultural sites now. Especially, the recent application of sensor network related technology is quite notable. Considering the efficiency of MAC protocol of WSN is being researched in various aspects, it is believed that a research on how to apply the MAC protocol to agriculture would be also required. This research is based on the sensor node developed by Sunchon University ITRC. Once the sensor nodes are effectively located in the farm, they operate for a long time and they are rarely relocated once installed. The concentration of multiple sensor nodes in a narrow area is another characteristic the sensor node. The purpose of this research is to select a sensor network MAC protocol, which would be most proper to agricultural site with good energy efficiency and excellent transmission delay performance. The applicable protocols such as S-MAC and X-MAC were set up for the installation environment. They were compared and a methodology to select the most optimum protocol to agricultural site is suggested.

  10. Throughput and Packet Delay Analysis of the Intermittent DCF for Overlay Access Networks

    NASA Astrophysics Data System (ADS)

    Adamis, Athanassios V.; Maliatsos, Konstantinos N.; Constantinou, Philip

    Overlay Access Technology can compensate for the spectrum underutilization problem by exploiting Cognitive Radios capabilities. MAC design is an important aspect of Overlay Access research. In this paper we present the overlay access environment and the challenges it poses to MAC design. Then, we propose the use of a modified Distributed Coordination Function as the MAC protocol for distributed Overlay Access networks. The resulted Intermittent DCF performs with robustness in the demanding overlay access environment, which is characterized by frequent spectrum scan procedure interruptions and low achievable transmission rates. The most recent DCF Markov Chain Model is extended in order to include the overlay operation modifications. Our extension concerns the slot duration expectations calculation which, in the overlay environment, have not constant values but depend on overlay operation parameters. Using the analytical model we evaluate the performance of the DCF under the effect of certain overlay access parameters. The new analytical model predictions are validated with simulations, and are found to accurately capture many interesting features of the overlay operation. Our model can be used in feasibility studies of realistic overlay scenarios and in admission control algorithms of QoS enabled distributed overlay access networks that engage the Intermittent DCF.

  11. Channel catfish

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This book chapter provides a comprehensive overview of channel catfish aquaculture. Sections include fish biology; commercial culture; culture facilities; production practices; water quality management; nutrition, feeding and feed formulation; infectious diseases; harvesting and processing; and the...

  12. Optimal sensor placement for maximum area coverage (MAC) for damage localization in composite structures

    NASA Astrophysics Data System (ADS)

    Thiene, M.; Sharif Khodaei, Z.; Aliabadi, M. H.

    2016-09-01

    In this paper an optimal sensor placement algorithm for attaining the maximum area coverage (MAC) within a sensor network is presented. The proposed novel approach takes into account physical properties of Lamb wave propagation (attenuation profile, direction dependant group velocity due to material anisotropy) and geometrical complexities (boundary reflections, presence of openings) of the structure. A feature of the proposed optimization approach lies in the fact that it is independent of characteristics of the damage detection algorithm (e.g. probability of detection) making it readily up-scalable to large complex composite structures such as aircraft stiffened composite panel. The proposed fitness function (MAC) is independent of damage parameters (type, severity, location). Statistical analysis carried out shows that the proposed optimum sensor network with MAC results in high probability of damage localization. Genetic algorithm is coupled with the fitness function to provide an efficient optimization strategy.

  13. Single-dose intravenous gammaglobulin can stabilize neutrophil Mac-1 activation in sickle cell pain crisis

    PubMed Central

    Manwani, Deepa; Chen, Grace; Carullo, Veronica; Serban, Stelian; Olowokure, Olugbenga; Jang, Jungeun; Huggins, Matthew; Cohen, Hillel W.; Billett, Henny; Atweh, George F.; Frenette, Paul S.; Shi, Patricia A.

    2015-01-01

    Intravenous immunoglobulin (IVIG) decreases neutrophil adhesion to endothelium and red blood cell-neutrophil interactions in sickle cell mice undergoing vaso-occlusion. In this Phase I clinical trial of sickle cell anemia (SCA) patients admitted with pain crisis, we evaluated the status of adhesion molecules on neutrophils in control and IVIG-treated subjects pre- and post-infusion up to 800 mg/kg, the same dose used in murine studies. Mac-1 function significantly decreased from baseline in the low-dose IVIG (200–400 mg/kg) cohorts. IVIG-related adverse events may have occurred in the high-dose (600–800 mg/kg) cohorts. There were no significant increases in neutrophil and leukocyte counts, suggesting that IVIG may more selectively inhibit Mac-1 function as opposed to neutrophil adhesion. This study provides the first in-human validation of pre-clinical murine studies that IVIG can decrease Mac-1 function. PMID:25616042

  14. Disruption of the MacMARCKS gene prevents cranial neural tube closure and results in anencephaly.

    PubMed Central

    Chen, J; Chang, S; Duncan, S A; Okano, H J; Fishell, G; Aderem, A

    1996-01-01

    MacMARCKS is a member of the MARCKS family of protein kinase C (PKC) substrates. Biochemical evidence demonstrates that these proteins integrate calcium and PKC-dependent signals to regulate actin structure at the membrane. We report here that deletion of the MacMARCKS gene prevents cranial neural tube closure in the developing brain, resulting in anencephaly. This suggests a central role for MacMARCKS and the PKC signal transduction pathway in the folding of the anterior neural plate during the early phases of brain formation, and supports the hypothesis that actin-based motility directs cranial neural tube closure. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:8692805

  15. MacPASCO - A Macintosh-based, interactive graphic preprocessor for structural analysis and sizing

    NASA Technical Reports Server (NTRS)

    Lucas, S. H.; Davis, R. C.

    1991-01-01

    MacPASCO, an interactive, graphic preprocessor for panel design is described. MacPASCO creates input for PASCO, an existing computer code for structural analysis and optimization of longitudinal stiffened composite panels. By using a graphical user interface, MacPASCO simplifies the specification of panel geometry and reduces user input errors, thus making the modeling and analysis of panel designs more efficient. The user draws the initial structural geometry on the computer screen, then uses a combination of graphic and text inputs to: refine the structural geometry, specify information required for analysis such as panel load conditions, and define design variables and constraints for minimum-mass optimization. Composite panel design is an ideal application because the graphical user interface can: serve as a visual aid, eliminate the tedious aspects of text-based input, and eliminate many sources of input errors.

  16. A network architecture for precision formation flying using the IEEE 802.11 MAC Protocol

    NASA Technical Reports Server (NTRS)

    Clare, Loren P.; Gao, Jay L.; Jennings, Esther H.; Okino, Clayton

    2005-01-01

    Precision Formation Flying missions involve the tracking and maintenance of spacecraft in a desired geometric formation. The strong coupling of spacecraft in formation flying control requires inter-spacecraft communication to exchange information. In this paper, we present a network architecture that supports PFF control, from the initial random deployment phase to the final formation. We show that a suitable MAC layer for the application protocol is IEEE's 802.11 MAC protocol. IEEE 802.11 MAC has two modes of operations: DCF and PCF. We show that DCF is suitable for the initial deployment phase while switching to PCF when the spacecraft are in formation improves jitter and throughput. We also consider the effect of routing on protocol performance and suggest when it is profitable to turn off route discovery to achieve better network performance.

  17. Resilient packet ring media access protocol

    NASA Astrophysics Data System (ADS)

    Thepot, Frederic

    2001-07-01

    The discussion will cover the new initiative to create a new MAC layer standard for resilient packet rings: IEEE 802.17 RPR. The key aspects of the presentation will include a preliminary address of the Metro Area Network today and the current networking technologies such as SONET/SDH which are not optimized to carry IP traffic over Metro MAN. The next segment will cover the options which could change the traditional and expensive layered networking model, and address the real benefits of marrying several technologies like Ethernet, SONET/SDH and IP into one technology. The next part of the discussion will detail the technical advantages a new MAC will bring to the services providers. Lastly a summary of the view and strategy about the acceptance and deployment of this new technology in the next 12 months, specifically, now one defines and develops standards for a Resilient Packet Ring Access Protocol for use in Local, Metropolitan, and Wide Area Networks for transfer of data packets at rates scalable to multiple gigabits per second; specifically address the data transmission requirements of carriers that have present and planned fiber optic physical infrastructure in a ring topology; and, defining and developing detailed specifications for using existing and/or new physical layers at appropriate data rates that will support transmission of this access protocol.

  18. The intracellular bacterium Rhodococcus equi requires Mac-1 to bind to mammalian cells.

    PubMed Central

    Hondalus, M K; Diamond, M S; Rosenthal, L A; Springer, T A; Mosser, D M

    1993-01-01

    Rhodococcus equi is a facultative intracellular bacterium of macrophages that causes disease in immunocompromised individuals, particularly those with AIDS. In this report, we demonstrate that R. equi binding to mammalian cells requires complement and is mediated primarily by the leukocyte complement receptor, Mac-1. Bacteria bind to macrophages poorly unless exogenous complement is added to the incubation medium. The addition of fresh nonimmune serum, which contains no detectable antibodies to R. equi, greatly enhances bacterial binding to macrophages, whereas heat inactivation of this serum or immunological depletion of C3 from the serum reduces binding to levels only slightly higher than those of binding under serum-free conditions. Human serum depleted of C2 or C4 is fully opsonic, indicating that complement activation and fixation occur by the alternative pathway. The serum-dependent binding of rhodococci to macrophages is mediated primarily by the macrophage complement receptor type 3, Mac-1 (CD11b/CD18). Bacteria do not bind to fibroblastoid or epithelial cells that lack this receptor. Most of the bacterial binding to macrophages is inhibited by a monoclonal antibody to Mac-1 but is unaffected by a monoclonal antibody to complement receptor type 1. Furthermore, opsonized, but not unopsonized, bacteria bind to purified Mac-1 immobilized on plastic. In addition, in the presence of opsonic complement, rhodococci bind efficiently to fibroblastoid cells transfected with cloned Mac-1 but relatively poorly to cells transfected with the complement receptor type 1. Hence, R. equi fixes complement by activating the alternative complement pathway, and this fixation is a requirement for bacterial adhesion and invasion. Furthermore, complement fixation defines rhodococcal host cell tropism, since R. equi binds specifically and exclusively to cells expressing Mac-1. Images PMID:8514396

  19. Town + Gown + CATV = Community Access.

    ERIC Educational Resources Information Center

    Clemens, Donald J.

    1980-01-01

    Describes a cooperative venture between Paducah Community College, Comcast Cable, and Paducah, Kentucky, and the roles each of these organizations played in establishing a public access channel which would provide informational and general interest programs, as well as college courses. Offers information on programing, financial support, and…

  20. POD/MAC-Based Modal Basis Selection for a Reduced Order Nonlinear Response Analysis

    NASA Technical Reports Server (NTRS)

    Rizzi, Stephen A.; Przekop, Adam

    2007-01-01

    A feasibility study was conducted to explore the applicability of a POD/MAC basis selection technique to a nonlinear structural response analysis. For the case studied the application of the POD/MAC technique resulted in a substantial improvement of the reduced order simulation when compared to a classic approach utilizing only low frequency modes present in the excitation bandwidth. Further studies are aimed to expand application of the presented technique to more complex structures including non-planar and two-dimensional configurations. For non-planar structures the separation of different displacement components may not be necessary or desirable.

  1. Comparison of the C-MAC D-Blade, Conventional C-MAC, and Macintosh Laryngoscopes in Simulated Easy and Difficult Airways

    PubMed Central

    Kılıçaslan, Alper; Topal, Ahmet; Erol, Atilla; Uzun, Sema Tuncer

    2014-01-01

    Objective Recently, to further enhance the potential in the management of difficult airways, the highly angulated D-Blade was added to the C-MAC system. The purpose of this study was to investigate the laryngoscopic view and intubation parameters using the new C-MAC D-Blade in comparison to the conventional C-MAC video laryngoscope and Macintosh direct laryngoscope in simulated easy and difficult airways. Methods We recruited 26 experienced anaesthesia providers into a randomized trial. Each performed tracheal intubation of a Laerdal SimMan® manikin with each laryngoscope in the following laryngoscopy scenarios: (1) normal airway, (2) cervical spine immobilization, and (3) tongue edema. The intubation times, success rates, number of intubation attempts, laryngoscopic views, and severity of dental compression were recorded. Results In all scenarios, video laryngoscopes provided better laryngeal exposure than the ML and appeared to produce less dental pressure. In the cervical spine immobilization scenario, D-Blade caused less dental pressure and showed better Cormack-Lehane (CL) classes than the other devices (p<0.001). There were no differences between video laryngoscopes in success of tracheal intubation (p>0.05). The CMAC provided the most rapid intubation. The rate of failure was 19% with ML. In the tongue edema scenario, the CMAC provided the most rapid and successful intubation (p<0.001). There were no differences between video laryngoscopes in laryngoscopic views according to CL classification and dental pressure (p>0.05). The rate of failure was 46% with the ML and 7% with the D-Blade. Conclusion The CMAC D-Blade caused less dental pressure than the conventional C-MAC and ML in the cervical immobilization scenario. The conventional CMAC performed better than the D-Blade and ML in the tongue edema scenario. These two video laryngoscopes may complement each other in various difficult airway situations. PMID:27366418

  2. An ultra low-power and traffic-adaptive medium access control protocol for wireless body area network.

    PubMed

    Ullah, Sana; Kwak, Kyung Sup

    2012-06-01

    Wireless Body Area Network (WBAN) consists of low-power, miniaturized, and autonomous wireless sensor nodes that enable physicians to remotely monitor vital signs of patients and provide real-time feedback with medical diagnosis and consultations. It is the most reliable and cheaper way to take care of patients suffering from chronic diseases such as asthma, diabetes and cardiovascular diseases. Some of the most important attributes of WBAN is low-power consumption and delay. This can be achieved by introducing flexible duty cycling techniques on the energy constraint sensor nodes. Stated otherwise, low duty cycle nodes should not receive frequent synchronization and control packets if they have no data to send/receive. In this paper, we introduce a Traffic-adaptive MAC protocol (TaMAC) by taking into account the traffic information of the sensor nodes. The protocol dynamically adjusts the duty cycle of the sensor nodes according to their traffic-patterns, thus solving the idle listening and overhearing problems. The traffic-patterns of all sensor nodes are organized and maintained by the coordinator. The TaMAC protocol is supported by a wakeup radio that is used to accommodate emergency and on-demand events in a reliable manner. The wakeup radio uses a separate control channel along with the data channel and therefore it has considerably low power consumption requirements. Analytical expressions are derived to analyze and compare the performance of the TaMAC protocol with the well-known beacon-enabled IEEE 802.15.4 MAC, WiseMAC, and SMAC protocols. The analytical derivations are further validated by simulation results. It is shown that the TaMAC protocol outperforms all other protocols in terms of power consumption and delay. PMID:20703634

  3. Education for Personal Life: John MacMurray on Why Learning to Be Human Requires Emotional Discipline

    ERIC Educational Resources Information Center

    MacAllister, James

    2014-01-01

    In this article I discuss the philosophy of John MacMurray, and in particular, his little-examined writings on discipline and emotion education. It is argued that discipline is a vital element in the emotion education MacMurray thought central to learning to be human, because for him it takes concerted effort to overcome the human tendency toward…

  4. Serum protein 90K/Mac-2BP is an independent predictor of disease severity during hepatitis C virus infection.

    PubMed

    Kittl, E M; Hofmann, J; Hartmann, G; Sebesta, C; Beer, F; Bauer, K; Huber, K R

    2000-03-01

    The serum protein designated 90K/Mac-2BP has been found at elevated concentrations in the sera of patients with various types of cancer and viral infections. The importance of the 90K/Mac-2BP serum concentrations in predicting the response towards interferon-alpha treatment for hepatitis C virus (HCV) infection prompted us to utilize a new ELISA for soluble human 90K/Mac-2BP to monitor the serum concentrations of this protein in our HCV-positive patients. Seventy HCV-PCR and anti-HCV antibody positive patients were analyzed for their serum levels of aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltransferase, cholinesterase, HCV-viral load, viral subtypes, and 90K/Mac-2BP. On correlation of age and 90K/Mac-2BP levels, we found an apparent correlation that was proved rather to be a strong dependence of 90K/Mac-2BP concentrations on disease severity/duration, which increases with age. Multiple correlation analysis demonstrated the independent nature of 90K/Mac-2BP concentrations, underscoring the potential high utility of this new marker. Our data corroborate the potential of the scavenger receptor family protein 90K/Mac-2BP as an independent predictor of disease severity during HCV infection. PMID:10905755

  5. An Application of MacLaury's Vantage Theory to Abstract Categories: Identity and the Process of Categorisation

    ERIC Educational Resources Information Center

    Fabiszak, Malgorzata

    2010-01-01

    This paper is an application of Robert E. MacLaury's Vantage Theory (VT) to the analysis of real life spoken discourse. It utilizes Dennis R. Preston's (1994) modification of MacLaury's VT. It elucidates how cognitive processes of coordinate selection and combination contribute to the on-line construction of category membership in the abstract…

  6. Changing the Shape of American Radio Drama: Innovation and Representation in Archibald MacLeish's "The Fall of the City."

    ERIC Educational Resources Information Center

    Novak, Glenn D.

    The (CBS Radio) Columbia Workshop, formed in 1936, encouraged the writing and production of creative, non-traditional radio drama such as Archibald MacLeish's verse play "The Fall of the City," which aired on April 11, 1937. MacLeish considered radio the ideal medium for poetry because it offers only aural stimuli without competition from visual…

  7. TRP channels.

    PubMed

    Benemei, Silvia; Patacchini, Riccardo; Trevisani, Marcello; Geppetti, Pierangelo

    2015-06-01

    Evidence is accumulating on the role of transient receptor potential (TRP) channels, namely TRPV1, TRPA1, TRPV4 and TRPM8, expressed by C- and Aδ-fibres primary sensory neurons, in cough mechanism. Selective stimuli for these channels have been proven to provoke and, more rarely, to inhibit cough. More importantly, cough threshold to TRP agonists is increased by proinflammatory conditions, known to favour cough. Off-target effects of various drugs, such as tiotropium or desflurane, seem to produce their protective or detrimental actions on airway irritation and cough via TRPV1 and TRPA1, respectively. Thus, TRPs appear to encode the process that initiates or potentiates cough, activated by exogenous irritants and endogenous proinflammatory mediators. More research on TRP channels may result in innovative cough medicines. PMID:25725213

  8. Upgrade of MacCHESS facility for X-ray scattering of biological macromolecules in solution

    PubMed Central

    Acerbo, Alvin Samuel; Cook, Michael J.; Gillilan, Richard Edward

    2015-01-01

    X-ray scattering of biological macromolecules in solution is an increasingly popular tool for structural biology and benefits greatly from modern high-brightness synchrotron sources. The upgraded MacCHESS BioSAXS station is now located at the 49-pole wiggler beamline G1. The 20-fold improved flux over the previous beamline F2 provides higher sample throughput and autonomous X-ray scattering data collection using a unique SAXS/WAXS dual detectors configuration. This setup achieves a combined q-range from 0.007 to 0.7 Å−1, enabling better characterization of smaller molecules, while opening opportunities for emerging wide-angle scattering methods. In addition, a facility upgrade of the positron storage ring to continuous top-up mode has improved beam stability and eliminated beam drift over the course of typical BioSAXS experiments. Single exposure times have been reduced to 2 s for 3.560 mg ml−1 lysozyme with an average quality factor I/σ of 20 in the Guinier region. A novel disposable plastic sample cell design that incorporates lower background X-ray window material provides users with a more pristine sample environment than previously available. Systematic comparisons of common X-ray window materials bonded to the cell have also been extended to the wide-angle regime, offering new insight into best choices for various q-space ranges. In addition, a quantitative assessment of signal-to-noise levels has been performed on the station to allow users to estimate necessary exposure times for obtaining usable signals in the Guinier regime. Users also have access to a new BioSAXS sample preparation laboratory which houses essential wet-chemistry equipment and biophysical instrumentation. User experiments at the upgraded BioSAXS station have been on-going since commissioning of the beamline in Summer 2013. A planned upgrade of the G1 insertion device to an undulator for the Winter 2014 cycle is expected to further improve flux by an order of magnitude. PMID

  9. Measurements of the Sunyaev-Zel'dovich Effect in MACS J0647.7+7015 and MACS J1206.2-0847 at High Angular Resolution with MUSTANG

    NASA Astrophysics Data System (ADS)

    Young, Alexander H.; Mroczkowski, Tony; Romero, Charles; Sayers, Jack; Balestra, Italo; Clarke, Tracy E.; Czakon, Nicole; Devlin, Mark; Dicker, Simon R.; Ferrari, Chiara; Girardi, Marisa; Golwala, Sunil; Intema, Huib; Korngut, Phillip M.; Mason, Brian S.; Mercurio, Amata; Nonino, Mario; Reese, Erik D.; Rosati, Piero; Sarazin, Craig; Umetsu, Keiichi

    2015-08-01

    We present high resolution (9″) imaging of the Sunyaev–Zel’dovich Effect (SZE) toward two massive galaxy clusters, MACS J0647.7+7015 (z = 0.591) and MACS J1206.2–0847 (z = 0.439). We compare these 90 GHz measurements, taken with the Multiplexed Squid/TES Array at Ninety Gigahertz (MUSTANG ) receiver on the Green Bank Telescope, with generalized Navarro–Frenk–White (gNFW) models derived from Bolocam 140 GHz SZE data as well as maps of the thermal gas derived from Chandra X-ray observations. We adopt a serial-fitting approach, in which gNFW models are first fit to the Bolocam data and then compared to the MUSTANG data to determine an overall best-fit model. For MACS J0647.7+7015, we find a gNFW profile with core slope parameter γ = 0.9 fits the MUSTANG image with {χ }{red}2=1.005 and probability to exceed (PTE) = 0.34. For MACS J1206.2–0847, we find γ =0.7, {χ }{red}2=0.993, and PTE = 0.70. In addition, we find a significant (>3σ) residual SZE feature in MACS J1206.2–0847 coincident with a group of galaxies identified in Very Large Telescope data and filamentary structure found in a weak-lensing mass reconstruction. We suggest the detected sub-structure may be the SZE decrement from a low mass foreground group or an infalling group. Giant Metrewave Radio Telescope measurements at 610 MHz reveal diffuse extended radio emission to the west, which we posit is either an active galactic nucleus-driven radio lobe, a bubble expanding away from disturbed gas associated with the SZE signal, or a bubble detached and perhaps re-accelerated by sloshing within the cluster. Using the spectroscopic redshifts available, we find evidence for a foreground (z = 0.423) or infalling group, coincident with the residual SZE feature.

  10. The Leishmania donovani histidine acid ecto-phosphatase LdMAcP: insight into its structure and function

    PubMed Central

    Papadaki, Amalia; Politou, Anastasia S.; Smirlis, Despina; Kotini, Maria P.; Kourou, Konstadina; Papamarcaki, Thomais; Boleti, Haralabia

    2015-01-01

    Acid ecto-phosphatase activity has been implicated in Leishmania donovani promastigote virulence. In the present study, we report data contributing to the molecular/structural and functional characterization of the L. donovani LdMAcP (L. donovani membrane acid phosphatase), member of the histidine acid phosphatase (HAcP) family. LdMAcP is membrane-anchored and shares high sequence identity with the major secreted L. donovani acid phosphatases (LdSAcPs). Sequence comparison of the LdMAcP orthologues in Leishmania sp. revealed strain polymorphism and species specificity for the L. donovani complex, responsible for visceral leishmaniasis (Khala azar), proposing thus a potential value of LdMAcP as an epidemiological or diagnostic tool. The extracellular orientation of the LdMAcP catalytic domain was confirmed in L. donovani promastigotes, wild-type (wt) and transgenic overexpressing a recombinant LdMAcP–mRFP1 (monomeric RFP1) chimera, as well as in transiently transfected mammalian cells expressing rLdMAcP–His. For the first time it is demonstrated in the present study that LdMAcP confers tartrate resistant acid ecto-phosphatase activity in live L. donovani promastigotes. The latter confirmed the long sought molecular identity of at least one enzyme contributing to this activity. Interestingly, the L. donovani rLdMAcP–mRFP1 promastigotes generated in this study, showed significantly higher infectivity and virulence indexes than control parasites in the infection of J774 mouse macrophages highlighting thereby a role for LdMAcP in the parasite's virulence. PMID:25695743

  11. The Leishmania donovani histidine acid ecto-phosphatase LdMAcP: insight into its structure and function.

    PubMed

    Papadaki, Amalia; Politou, Anastasia S; Smirlis, Despina; Kotini, Maria P; Kourou, Konstadina; Papamarcaki, Thomais; Boleti, Haralabia

    2015-05-01

    Acid ecto-phosphatase activity has been implicated in Leishmania donovani promastigote virulence. In the present study, we report data contributing to the molecular/structural and functional characterization of the L. donovani LdMAcP (L. donovani membrane acid phosphatase), member of the histidine acid phosphatase (HAcP) family. LdMAcP is membrane-anchored and shares high sequence identity with the major secreted L. donovani acid phosphatases (LdSAcPs). Sequence comparison of the LdMAcP orthologues in Leishmania sp. revealed strain polymorphism and species specificity for the L. donovani complex, responsible for visceral leishmaniasis (Khala azar), proposing thus a potential value of LdMAcP as an epidemiological or diagnostic tool. The extracellular orientation of the LdMAcP catalytic domain was confirmed in L. donovani promastigotes, wild-type (wt) and transgenic overexpressing a recombinant LdMAcP-mRFP1 (monomeric RFP1) chimera, as well as in transiently transfected mammalian cells expressing rLdMAcP-His. For the first time it is demonstrated in the present study that LdMAcP confers tartrate resistant acid ecto-phosphatase activity in live L. donovani promastigotes. The latter confirmed the long sought molecular identity of at least one enzyme contributing to this activity. Interestingly, the L. donovani rLdMAcP-mRFP1 promastigotes generated in this study, showed significantly higher infectivity and virulence indexes than control parasites in the infection of J774 mouse macrophages highlighting thereby a role for LdMAcP in the parasite's virulence. PMID:25695743

  12. Application of Multihop Relay for Performance Enhancement of AeroMACS Networks

    NASA Technical Reports Server (NTRS)

    Kamali, Behnam; Wilson, Jeffrey D.; Kerczewski, Robert J.

    2012-01-01

    A new transmission technology, based on IEEE 802.16-2009 (WiMAX), is currently being developed for airport surface communications. A C-band spectrum allocation at 5091-5150 MHz has been created by ITU to carry this application. The proposed technology, known as AeroMACS, will be used to support fixed and mobile ground to ground applications and services. This article proposes and demonstrates that IEEE 802.16j-amendment-based WiMAX is most feasible for AeroMACS applications. This amendment introduces multihop relay as an optional deployment that may be used to provide additional coverage and/or enhance the capacity of the network. Particular airport surface radio coverage situations for which IEEE 802.16-2009-WiMAX provides resolutions that are inefficient, costly, or excessively power consuming are discussed. In all these cases, it is argued that 16j technology offers a much better alternative. A major concern about deployment of AeroMACS is interference to co-allocated applications such as the Mobile Satellite Service (MSS) feeder link. Our initial simulation results suggest that no additional interference to MSS feeder link is caused by deployment of IEEE 802.16j-based AeroMACS.

  13. Teaching Justice after MacIntyre: Toward a Catholic Philosophy of Moral Education

    ERIC Educational Resources Information Center

    Bergman, Roger

    2008-01-01

    How is the commitment to social justice sustained over a lifetime? This would seem to be a matter of character, and that calls attention to the Aristotelian tradition in ethics. No one provides as much insight into the challenge of the contemporary appropriation of this tradition as Alasdair MacIntyre. Although a moral philosopher rather than a…

  14. Moraine Area Career System (MACS). Technology Preparation Final Report for 1992.

    ERIC Educational Resources Information Center

    Moraine Valley Community Coll., Palos Hills, IL.

    The Moraine Area Career System (MACS) Tech Prep Applied Academics Core project was undertaken to develop a written replicable model core of applied academics for selected vocational-technical programs that would emphasize Illinois goals for learning and technical content (including critical and computer literacy). A tech prep advisory council…

  15. Berkeley Lab Scientist Named MacArthur ''Genius'' Fellow for Audio Preservation Research

    SciTech Connect

    Haber, Carl

    2013-09-24

    Audio Preservationist Carl Haber was named a MacArthur Fellow in 2013. The Fellowship is a $625,000, no-strings-attached grant for individuals who have shown exceptional creativity in their work and the promise to do more. Learn more at http://www.macfound.org/fellows.

  16. Berkeley Lab Scientist Named MacArthur ''Genius'' Fellow for Audio Preservation Research

    ScienceCinema

    Haber, Carl

    2013-10-22

    Audio Preservationist Carl Haber was named a MacArthur Fellow in 2013. The Fellowship is a $625,000, no-strings-attached grant for individuals who have shown exceptional creativity in their work and the promise to do more. Learn more at http://www.macfound.org/fellows.

  17. A simulation study of TaMAC protocol using network simulator 2.

    PubMed

    Ullah, Sana; Kwak, Kyung Sup

    2012-10-01

    A Wireless Body Area Network (WBAN) is expected to play a significant role in future healthcare system. It interconnects low-cost and intelligent sensor nodes in, on, or around a human body to serve a variety of medical applications. It can be used to diagnose and treat patients with chronic diseases such as hypertensions, diabetes, and cardiovascular diseases. The lightweight sensor nodes integrated in WBAN require low-power operation, which can be achieved using different optimization techniques. We introduce a Traffic-adaptive MAC protocol (TaMAC) for WBAN that supports dual wakeup mechanisms for normal, emergency, and on-demand traffic. In this letter, the TaMAC protocol is simulated using a well-known Network Simulator 2 (NS-2). The problem of multiple emergency nodes is solved using both wakeup radio and CSMA/CA protocol. The power consumption, delay, and throughput performance are closely compared with beacon-enabled IEEE 802.15.4 MAC protocol using extensive simulations. PMID:21863319

  18. Geochemistry and petrography of the MacAlpine Hills lunar meteorites

    SciTech Connect

    Lindstrom, M.M.; McKay, D.S. ); Wentworth, S.J.; Martinez, R.R.; Mittlefehldt, D.W. ); Wang, Mingsheng; Lipschutz, M.E. )

    1991-11-01

    MacAlpine Hills 88104 and 88105 are anorthositic lunar meteorites recovered from the same area in Antarctica which are demonstrated to be paired samples of the same fall. Petrographic studies of matrix and clasts show that mAC88104/5 is a polymict breccia dominated by impact melt clasts. It contains a small amount of highland impact glass and very few regolith glass spherules. It is better classified as a fragmental breccia than a regolith breccia. The bulk composition is ferroan (mg{prime} = 63) and highly aluminous (Al{sub 2}O{sub 3} = 28%). REE and other incompatible element concentrations are very low. Compositions of anorthositic, granulitic, and impact melt breccia clasts are very similar to, but distinct from, matrix composition. MAC88104/5 is very similar in composition to the other anorthositic lunar meteorites, but each of the meteorites is distinct. The anorthositic lunar meteorites, especially MAC88104/5 and Y82192/3/86032, are very similar to North Ray Crater feldspathic fragmental breccias in composition and petrography. These fragmental lunar meteorites may have been ancient, deeply buried breccias from the megaregolith. Comparisons of chemical petrographic features and exposure histories suggest that the twelve lunar meteorites were derived from two to nine, but probably four to seven, impact onto the lunar surface. Discrepancies between the proportions of lunar meteorites and results of Apollo missions may be due to unrepresentative sampling. Lunar meteorites provide valuable new information on the nature of the lunar crust.

  19. A case of Mac Tel 2 with an unusual sub macular vitelliform lesion

    PubMed Central

    Lekha, T.; Sarwate, Nikit; Sarwate, Renuka

    2015-01-01

    Method: Observational case report describing the clinical, FFA, OCT and mfERG findings in an elderly female patient with atypical features of macular telangiectasia (Mac Tel 2) Results: A 71-year-old lady was detected to have characteristic features of Mac Tel 2 in the left eye (LE) and a yellowish sub macular vitelliform like lesion in the right eye (RE). FFA showed ill defined hyper fluorescence in the RE and telangiectasia and parafoveal leakage typical of Mac Tel 2 in the LE. On OCT RE had hyper reflective clump of echoes subfoveally with an intact RPE and LE had foveal thinning with hypo reflective intraretinal cavities. mfERG responses were normal in the RE and reduced in the LE. During the course of 3 years LE showed natural progression while RE remained unchanged. Conclusion: Structural and functional evaluation of an unusual sub macular vitelliform lesion seen in association with Mac Tel 2 and its course over a period of 3 years is described. The differentiating features of this lesion from adult onset foveomacular vitelliform dystrophy (AFMD) are discussed.

  20. Knowledge, Power, and Social Policy: John M. MacEachran and Alberta's 1928 Sexual Sterilization Act

    ERIC Educational Resources Information Center

    Puplampu, Korbla P.

    2008-01-01

    This article examines how academic knowledge and power have shaped the discourse on human classification and how political authorities use academic knowledge producers to legitimize public policy. Specifically, the article draws on the role of John M. MacEachran, a former academic at the University of Alberta, in the implementation of the Alberta…

  1. The Big Mac and Teaching about Japan. Footnotes. Volume 8, Number 5

    ERIC Educational Resources Information Center

    Ellington, Lucien

    2003-01-01

    The Big Mac can be effective tool in helping students achieve a better understanding of Japan. It can defeat Orientalist stereotypes about the Japanese--and also challenge young people who might have oversimplified notions of what exactly occurs when U.S. fast food chains take root in another culture. Many deride McDonald's as a villain…

  2. Testing Evolutionary Hypotheses in the Classroom with MacClade Software.

    ERIC Educational Resources Information Center

    Codella, Sylvio G.

    2002-01-01

    Introduces MacClade which is a Macintosh-based software package that uses the techniques of cladistic analysis to explore evolutionary patterns. Describes a novel and effective exercise that allows undergraduate biology majors to test a hypothesis about behavioral evolution in insects. (Contains 13 references.) (Author/YDS)

  3. Assessing Internalizing, Externalizing, and Attention Problems in Young Children: Validation of the MacArthur HBQ

    ERIC Educational Resources Information Center

    Lemery-Chalfant, Kathryn; Schreiber, Jane E.; Schmidt, Nicole L.; Van Hulle, Carol A.; Essex, Marilyn J.; Goldsmith, H. H.

    2007-01-01

    Objective: To test the validity of the MacArthur Health and Behavior Questionnaire (HBQ) using receiver operating characteristic (ROC) analysis to determine optimal thresholds for the HBQ in predicting Diagnostic Interview Schedule for Children Version-IV (DISC-IV)diagnoses. The roles of child sex, level of impairment, and physical health in…

  4. Pok-O-MacCready Outdoor Education Center Resident Program Guide.

    ERIC Educational Resources Information Center

    Swan, Jack

    The guide describes the 300-acre Pok-O-MacCready Outdoor Education Center, located in the Adirondack Mountains, which offers winterized residential facilities and indivdualized 3- to 5-day outdoor and environmental programs for groups of up to 85 elementary and secondary students. The guide describes the center's activities, which focus on…

  5. 42 CFR 405.1122 - What evidence may be submitted to the MAC.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false What evidence may be submitted to the MAC. 405.1122 Section 405.1122 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM FEDERAL HEALTH INSURANCE FOR THE AGED AND DISABLED Determinations, Redeterminations, Reconsiderations, and...

  6. Mineral-chemical comparisons of MAC88105 with Yamato lunar meteorites

    SciTech Connect

    Takeda, Hiroshi; Mori, Hiroshi; Saito, Jun ); Miyamoto, Masamichi )

    1991-11-01

    The new lunar meteorite MAC88105 has been studied by mineral-chemical techniques and was compared with the Yamato lunar meteorites. Clast types and pyroxene compositions of MAC88105 indicate that evidence for a pairing with any known lunar meteorites is unlikely. Clast-laden vitric breccia and comminuted mineral fragments in glassy matrix are common components as in other lunar meteorites, but granulitic clasts are not as common as in other lunar meteorites. The large and common granulite-like meta-igneous clasts still preserve lath-shaped plagioclase crystals with fine-grained olivine and pyroxenes in the interstices. Pyroxenes with mg number = Mg {times} 100/(Mg + Fe) between 70-48 mol% are common, but more Mg-rich pyroxenes and plutonic pyroxenes from nonmare pristine crustal rocks are rare. One basaltic clast contains pyroxenes with zoning trends more MG-rich than the above mg range and than those of the VLT basalts common in lunar meteorites. MAC88105 preserves true glass in the matrix as observed by a transmission electron microscope (TEM). The preservation of glassy materials indicates that MAC 88105 had a metamorphic annealing history different from other lunar meteorites.

  7. Evidence for MAC waves in the core and implications for the thermal state

    NASA Astrophysics Data System (ADS)

    Buffett, B. A.; Holme, R. T.; Knezek, N. R.

    2015-12-01

    Earth's liquid core hosts a diverse set of waves with periods ranging from days to thousands of years. One class of waves with periods of several decades are known to arise from an interplay between magnetic, Archimedes and Coriolis forces. These so-called MAC waves are thought to be relevant for interpreting historical fluctuations in the geomagnetic field. We show that MAC waves provide a good description of time-dependent zonal flow at the top of the core. The same collection of waves also offers a simple explanation for observed fluctuations in the dipole field. Both of these predictions require a 140-kilometer-thick stratified layer at the top of the core with a buoyancy frequency comparable to Earth's rotation rate. We extend these predictions to include changes in the length of day and find that MAC waves can account for about half of the observed fluctuation at decadal periods. Larger fluctuations are possible when electromagnetic stresses couple MAC waves to flow in the interior of the core. In fact, an idealized model for the coupled system over estimates the length-of-day fluctuations, possibly reflecting limitations in the idealized model. The waves do not discriminate between thermal and compositional stratification at the top of the core, but the properties of the layer are compatible with thermal stratification, implying a core heat flow of 13 TW relative to an adiabatic heat flow of 15 TW.

  8. There is no MacWilliams identity for convolutional codes. [transmission gain comparison

    NASA Technical Reports Server (NTRS)

    Shearer, J. B.; Mceliece, R. J.

    1977-01-01

    An example is provided of two convolutional codes that have the same transmission gain but whose dual codes do not. This shows that no analog of the MacWilliams identity for block codes can exist relating the transmission gains of a convolutional code and its dual.

  9. Dependence of AeroMACS Interference on Airport Radiation Pattern Characteristics

    NASA Technical Reports Server (NTRS)

    Wilson, Jeffrey D.

    2012-01-01

    AeroMACS (Aeronautical Mobile Airport Communications System), which is based upon the IEEE 802.16e mobile wireless standard, is expected to be implemented in the 5091 to 5150 MHz frequency band. As this band is also occupied by Mobile Satellite Service (MSS) feeder uplinks, AeroMACS must be designed to avoid interference with this incumbent service. The aspects of AeroMACS operation that present potential interference are under analysis in order to enable the definition of standards that assure that such interference will be avoided. In this study, the cumulative interference power distribution at low earth orbit from AeroMACS transmitters at the 497 major airports in the contiguous United States was simulated with the Visualyse Professional software. The dependence of the interference power on the number of antenna beams per airport, gain patterns, and beam direction orientations was simulated. As a function of these parameters, the simulation results are presented in terms of the limitations on transmitter power required to maintain the cumulative interference power under the established threshold.

  10. Dependence of AeroMACS Interference on Airport Radiation Pattern Characteristics

    NASA Technical Reports Server (NTRS)

    Wilson, Jeffrey D.

    2012-01-01

    AeroMACS (Aeronautical Mobile Airport Communications System), which is based upon the IEEE 802.16e mobile wireless standard, is expected to be implemented in the 5091-5150 MHz frequency band. As this band is also occupied by Mobile Satellite Service (MSS) feeder uplinks, AeroMACS must be designed to avoid interference with this incumbent service. The aspects of AeroMACS operation that present potential interference are under analysis in order to enable the definition of standards that assure that such interference will be avoided. In this study, the cumulative interference power distribution at low earth orbit from AeroMACS transmitters at the 497 major airports in the contiguous United States was simulated with the Visualyse Professional software. The dependence of the interference power on the number of antenna beams per airport, gain patterns, and beam direction orientations was simulated. As a function of these parameters, the simulation results are presented in terms of the limitations on transmitter power required to maintain the cumulative interference power under the established threshold.

  11. 42 CFR 423.2108 - MAC Actions when request for review is filed.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM VOLUNTARY MEDICARE PRESCRIPTION DRUG BENEFIT Reopening, ALJ... jeopardize the enrollee's life or health or ability to regain maximum function. The MAC may consider this... calendar days after receiving the request for review, unless the 90 calendar day period has been...

  12. New upper bounds on the rate of a code via the Delsarte-MacWilliams inequalities

    NASA Technical Reports Server (NTRS)

    Mceliece, R. J.; Rodemich, E. R.; Rumsey, H., Jr.; Welch, L. R.

    1977-01-01

    An upper bound on the rate of a binary code as a function of minimum code distance (using a Hamming code metric) is arrived at from Delsarte-MacWilliams inequalities. The upper bound so found is asymptotically less than Levenshtein's bound, and a fortiori less than Elias' bound. Appendices review properties of Krawtchouk polynomials and Q-polynomials utilized in the rigorous proofs.

  13. Ber-MAC3: new monoclonal antibody that defines human monocyte/macrophage differentiation antigen.

    PubMed Central

    Backé, E; Schwarting, R; Gerdes, J; Ernst, M; Stein, H

    1991-01-01

    A new monoclonal antibody Ber-MAC3 is reported. It recognises a formol sensitive epitope of a not yet clustered monocyte/macrophage specific 140 kilodalton glycoprotein that is expressed on the cell surface and in the cytoplasm. In 30 cases of acute and chronic leukaemia, Ber-MAC3 staining was restricted to 15 myeloid leukaemias of M4 and M5 types. The tumour cells of two cases of true histiocytic malignancies were Ber-MAC3 positive, whereas those of all 280 malignancies of lymphocytic origin were negative. The latter included 52 cases of Hodgkin's disease and 41 cases of Ki-1 positive anaplastic large cell lymphomas which had previously been classified as true histiocytic lymphomas. Ber-MAC3 therefore seems to be of considerable value for selective identification of monocytes and macrophages at a certain stage of differentiation and seems to be suitable for diagnosing myelomonocytic or monocytic leukaemia and neoplasms of true histiocytic origin. Images PMID:1721628

  14. Application of Multihop Relay for Performance Enhancement of AeroMACS Networks

    NASA Technical Reports Server (NTRS)

    Kamali, Behnam; Wilson, Jeffrey D.; Kerczewski, Robert J.

    2012-01-01

    A new transmission technology, based on IEEE 802.16-2009 (WiMAX), is currently being developed for airport surface communications. A C-band spectrum allocation at 5091 to 5150 MHz has been created by International Telecommunications Union (ITU) to carry this application. The proposed technology, known as AeroMACS, will be used to support fixed and mobile ground to ground applications and services. This article proposes and demonstrates that IEEE 802.16j-amendment-based WiMAX is most feasible for AeroMACS applications. This amendment introduces multihop relay as an optional deployment that may be used to provide additional coverage and/or enhance the capacity of the network. Particular airport surface radio coverage situations for which IEEE 802.16-2009-WiMAX provides resolutions that are inefficient, costly, or excessively power consuming are discussed. In all these cases, it is argued that 16j technology offers a much better alternative. A major concern about deployment of AeroMACS is interference to co-allocated applications such as the Mobile Satellite Service (MSS) feeder link. Our initial simulation results suggest that no additional interference to MSS feeder link is caused by deployment of IEEE 802.16j-based AeroMACS.

  15. Using a Networked Mac Lab To Facilitate Learning in Art, Foreign Languages, and English.

    ERIC Educational Resources Information Center

    Brutchin, Patricia; And Others

    These presentations examine the use of a new Macintosh Lab in Commercial Art Technology, Spanish, and English Composition classes at Clark State Community College. The first paper describes the Commercial Art Technology program at the college, highlighting the use of the Mac Lab installed in September 1993 and discussing the Electronic Publishing,…

  16. Leadership and Some Related Propositions: A Response to the Ideas of James MacGregor Burns.

    ERIC Educational Resources Information Center

    Bleedorn, Berenice D.

    The theories of James MacGregor Burns as expressed in his book, "Leadership" (1978), suggest that transformational leadership engages all persons to varying degrees throughout the levels and interstices of society. Burns believes that the transforming leader not only exploits a need or demand of a follower but also looks for his potential motives…

  17. An Evaluation of the MacMagic Program at Davidson Middle School.

    ERIC Educational Resources Information Center

    Mergendoller, John R.; Pardo, Elly B.

    This report evaluates the second year of the MacMagic program at Davidson Middle School in San Rafael, California. The program uses Macintosh computers, video cameras, tape recorders, and other related technology in a team teaching environment to enhance thinking and learning in an integrated English, history, and multimedia course. Children from…

  18. Protoporphyrin (PPIX) efflux by the MacAB-TolC pump in Escherichia coli.

    PubMed

    Turlin, Evelyne; Heuck, Gesine; Simões Brandão, Maria Inês; Szili, Noémie; Mellin, J R; Lange, Norbert; Wandersman, Cécile

    2014-12-01

    In most organisms, heme biosynthesis is strictly controlled so as to avoid heme and heme precursor accumulation, which is toxic. Escherichia coli regulates heme biosynthesis by a feedback loop involving heme-induced proteolytic cleavage of HemA, glutamyl-tRNA reductase, which is the first enzyme in the heme biosynthetic pathway. We show here that heme homeostasis can be disrupted by overproduction of YfeX, a cytoplasmic protein that captures iron from heme that we named deferrochelatase. We also show that it is disrupted by iron chelation, which reduces the intracellular iron concentration necessary for loading iron into protoporphyrin IX (PPIX, the immediate heme precursor). In both cases, we established that there is an increased PPIX concentration and we demonstrate that this compound is expelled by the MacAB-TolC pump, an efflux pump involved in E. coli and Salmonella for macrolide efflux. The E. coli macAB and tolC mutants accumulate PPIX and are sensitive to photo-inactivation. The MacAB-TolC pump is required for Salmonella typhimurium survival in macrophages. We propose that PPIX is an endogenous substrate of the MacAB-TolC pump in E. coli and S. typhimurium and that this compound is produced inside bacteria when natural heme homeostasis is disrupted by iron shortage, as happens when bacteria invade the mammalian host. PMID:25257218

  19. Predicting Outcomes of Children Referred for Autism Using the MacArthur-Bates Communicative Development Inventory

    ERIC Educational Resources Information Center

    Luyster, Rhiannon; Qiu, Shanping; Lopez, Kristina; Lord, Catherine

    2007-01-01

    Purpose: Autism spectrum disorders (ASD) are characterized by early impairments in language and related social communication skills. This investigation explored whether scores on the MacArthur-Bates Communicative Development Inventory (CDI) at ages 2 and 3 years predict outcome at age 9 years in children with ASD and developmental delay (DD).…

  20. Short-Form Versions of the Spanish MacArthur-Bates Communicative Development Inventories

    ERIC Educational Resources Information Center

    Jackson-Maldonodo, Donna; Marchman, Virginia A.; Fernald, Lia C. H.

    2013-01-01

    The Spanish-language MacArthur-Bates Communicative Development Inventories (S-CDIs) are well-established parent report tools for assessing the language development of Spanish-speaking children under 3 years. Here, we introduce the short-form versions of the S-CDIs (SFI and SFII), offered as alternatives to the long forms for screening purposes or…

  1. Detecting DIF in Polytomous Items Using MACS, IRT and Ordinal Logistic Regression

    ERIC Educational Resources Information Center

    Elosua, Paula; Wells, Craig

    2013-01-01

    The purpose of the present study was to compare the Type I error rate and power of two model-based procedures, the mean and covariance structure model (MACS) and the item response theory (IRT), and an observed-score based procedure, ordinal logistic regression, for detecting differential item functioning (DIF) in polytomous items. A simulation…

  2. LFA-1 and Mac-1 integrins bind to the serine/threonine-rich domain of thrombomodulin.

    PubMed

    Kawamoto, Eiji; Okamoto, Takayuki; Takagi, Yoshimi; Honda, Goichi; Suzuki, Koji; Imai, Hiroshi; Shimaoka, Motomu

    2016-05-13

    LFA-1 (αLβ2) and Mac-1 (αMβ2) integrins regulate leukocyte trafficking in health and disease by binding primarily to IgSF ligand ICAM-1 and ICAM-2 on endothelial cells. Here we have shown that the anti-coagulant molecule thrombomodulin (TM), found on the surface of endothelial cells, functions as a potentially new ligand for leukocyte integrins. We generated a recombinant extracellular domain of human TM and Fc fusion protein (TM-domains 123-Fc), and showed that pheripheral blood mononuclear cells (PBMCs) bind to TM-domains 123-Fc dependent upon integrin activation. We then demonstrated that αL integrin-blocking mAb, αM integrin-blocking mAb, and β2 integrin-blocking mAb inhibited the binding of PBMCs to TM-domains 123-Fc. Furthermore, we show that the serine/threonine-rich domain (domain 3) of TM is required for the interaction with the LFA-1 (αLβ2) and Mac-1 (αMβ2) integrins to occur on PBMCs. These results demonstrate that the LFA-1 and Mac-1 integrins on leukocytes bind to TM, thereby establishing the molecular and structural basis underlying LFA-1 and Mac-1 integrin interaction with TM on endothelial cells. In fact, integrin-TM interactions might be involved in the dynamic regulation of leukocyte adhesion with endothelial cells. PMID:27055590

  3. 78 FR 26711 - Federal Agricultural Mortgage Corporation Funding and Fiscal Affairs; Farmer Mac Liquidity...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-08

    ... liquidity reserve and the supplemental liquidity buffer in Sec. 652.40. \\1\\ 76 FR 71798 (Nov. 18, 2011). \\2.... This final rule amended Sec. Sec. 652.10, 652.15, 652.25, 652.30, and 652.45. See 77 FR 66375. In a...; Farmer Mac Liquidity Management ACTION: Proposed rule; reopening of comment period. SUMMARY: The...

  4. Hemodialysis access - self care

    MedlinePlus

    Kidney failure - chronic-hemodialysis access; Renal failure - chronic-hemodialysis access; Chronic renal insufficiency - hemodialysis access; Chronic kidney failure - hemodialysis access; Chronic renal failure - hemodialysis access; dialysis - hemodialysis access

  5. Characterizing the Interaction Between Routing and MAC Protocols in Ad-Hoc Networks

    SciTech Connect

    Barrett, C. L.; Drozda, M.; Marathe, A.; Marathe, M. V.

    2002-01-01

    We empirically study the effect of mobility on the performance of protocols designed for wireless ad-hoc networks. An important objective is to study the interaction of the Routing and MAC layer protocols under different mobility parameters. We use three basic mobility models: grid mobility model, random waypoint model, and exponential correlated random model. The performance of protocols is measured in terms of (i) latency, (ii) throughput, (iii) number of packets received, (iv) long term fairness and (v) number of control packets at the MAC and routing layer level. Three different commonly studied routing protocols are used: AODV, DSR and LAR1. Similarly three well known MAC protocols are used: MACA, 802.1 1 and CSMA. Our main contribution is simulation based experiments coupled with rigorous statistical analysis to characterize the interaction of MAC layer protocols with routing layer protocols in ad-hoc networks. From the results, we can conclude the following: e No single MAC or Routing protocol dominated the other protocols in their class. Probably more interestingly, no MAURouting protocol combination was better than other combinations over all scenarios and response variables. 0 In general, it is not meaningful to speak about a MAC or a routing protocol in isolation. Presence of interaction leads to trade-offs between the amount of control packets generated by each layer. The results raise the possibility of improving the performance of a particular MAC layer protocol by using a cleverly designed routing protocol or vice-versa. Thus in order to improve the performanceof a communication network, it is important to study the entire protocol stack as a single algorithmic construct; optimizing individual layers in the seven layer OS1 stack will not yield performance improvements beyond a point. A methodological contribution of this paper is the use of statistical methods such as analysis of variance (ANOVA), to characterize the interaction between the protocols

  6. 47 CFR 76.978 - Leased access annual reporting requirement.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... rate and actual rates. (5) The programmers using each commercial leased access channel and whether each programmer is using the channel on a full-time or part-time basis. (6) The number of requests received for... different rates, terms, or conditions on commercial leased access programmers (such as with respect...

  7. 47 CFR 76.978 - Leased access annual reporting requirement.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... rate and actual rates. (5) The programmers using each commercial leased access channel and whether each programmer is using the channel on a full-time or part-time basis. (6) The number of requests received for... different rates, terms, or conditions on commercial leased access programmers (such as with respect...

  8. 47 CFR 76.978 - Leased access annual reporting requirement.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... rate and actual rates. (5) The programmers using each commercial leased access channel and whether each programmer is using the channel on a full-time or part-time basis. (6) The number of requests received for... different rates, terms, or conditions on commercial leased access programmers (such as with respect...

  9. MacA is a Second Cytochrome c Peroxidase of Geobacter sulfurreducens

    PubMed Central

    Seidel, Julian; Hoffmann, Maren; Ellis, Katie E.; Seidel, Antonia; Spatzal, Thomas; Gerhardt, Stefan; Elliott, Sean J.

    2012-01-01

    The metal-reducing δ-proteobacterium Geobacter sulfurreducens produces a large number of c-type cytochromes, many of which have been implicated in the transfer of electrons to insoluble metal oxides. Among these, the dihemic MacA was assigned a central role. Here we have produced G. sulfurreducens MacA by recombinant expression in Escherichia coli and have solved its three-dimensional structure in three different oxidation states. Sequence comparisons group MacA into the family of diheme cytochrome c peroxidases, and the protein indeed showed hydrogen peroxide reductase activity with ABTS2– as an electron donor. The observed KM was 38.5 ± 3.7 μM H2O2 and vmax was 0.78 ± 0.03 μmol H2O2·min–1·mg–1, resulting in a turnover number kcat = 0.46 · s–1. In contrast, no Fe(III) reductase activity was observed. MacA was found to display similar electrochemical properties to other bacterial diheme peroxidases, in additional to the ability to electrochemically mediate electron transfer to the soluble cytochrome PpcA. Differences in activity between CcpA and MacA can be rationalized with structural variations in one of the three loop regions, loop 2, that undergo conformational changes during reductive activation of the enzyme. This loop is adjacent to the active site heme and forms an open loop structure rather than a more rigid helix as in CcpA. For the activation of the protein the loop has to displace the distal ligand to the active site heme, H93, in loop 1. A H93G variant showed an unexpected formation of a helix in loop 2 and disorder in loop 1, while a M297H variant that altered the properties of the electron transfer heme abolished reductive activation. PMID:22417533

  10. Hemodialysis access - self care

    MedlinePlus

    Kidney failure - chronic-hemodialysis access; Renal failure - chronic-hemodialysis access; Chronic renal insufficiency - hemodialysis access; Chronic kidney failure - hemodialysis access; Chronic renal failure - ...

  11. THE ISOLATION AND IDENTIFICATION OF MYCOBACTERIUM AVIUM COMPLEX (MAC) RECOVERED FROM LOS ANGELES POTABLE WATER, A POSSIBLE SOURCE OF INFECTION IN AIDS PATIENTS

    EPA Science Inventory

    Los Angeles water was investigated as a possible source of Mycobacterium avium complex (MAC) infection in patients with AIDS. MAC consists of M.avium (MA), M. intracellulare (MI) and Mycobacterium X (MX)(positive for MAC by DNA probe but not MA or MI). The study included 13 reser...

  12. Expanding Access

    ERIC Educational Resources Information Center

    Roach, Ronald

    2007-01-01

    There is no question that the United States lags behind most industrialized nations in consumer access to broadband Internet service. For many policy makers and activists, this shortfall marks the latest phase in the struggle to overcome the digital divide. To remedy this lack of broadband affordability and availability, one start-up firm--with…

  13. Access Denied

    ERIC Educational Resources Information Center

    Raths, David

    2012-01-01

    As faculty members add online and multimedia elements to their courses, colleges and universities across the country are realizing that there is a lot of work to be done to ensure that disabled students (and employees) have equal access to course material and university websites. Unfortunately, far too few schools consider the task a top priority.…

  14. Easy Access

    ERIC Educational Resources Information Center

    Gettelman, Alan

    2009-01-01

    School and university restrooms, locker and shower rooms have specific ADA accessibility requirements that serve the needs of staff, students and campus visitors who are disabled as a result of injury, illness or age. Taking good care of them is good for the reputation of a sensitive community institution, and fosters positive public relations.…

  15. The channels of Mars

    NASA Technical Reports Server (NTRS)

    Baker, Victor R.

    1988-01-01

    The geomorphology of Mars is discussed, focusing on the Martian channels. The great flood channels of Mars, the processes of channel erosion, and dendritic channel networks, are examined. The topography of the Channeled Scabland region of the northwestern U.S. is described and compared to the Martian channels. The importance of water in the evolution of the channel systems is considered.

  16. Directional MAC approach for wireless body area networks.

    PubMed

    Hussain, Md Asdaque; Alam, Md Nasre; Kwak, Kyung Sup

    2011-01-01

    Wireless Body Area Networks (WBANs) designed for medical, sports, and entertainment applications, have drawn the attention of academia and industry alike. A WBAN is a special purpose network, designed to operate autonomously to connect various medical sensors and appliances, located inside and/or outside of a human body. This network enables physicians to remotely monitor vital signs of patients and provide real time feedback for medical diagnosis and consultations. The WBAN system can offer two significant advantages: patient mobility due to their use of portable monitoring devices and a location independent monitoring facility. With its appealing dimensions, it brings about a new set of challenges, which we do not normally consider in such small sensor networks. It requires a scalable network in terms of heterogeneous data traffic, low power consumption of sensor nodes, integration in and around the body networking and coexistence. This work presents a medium access control protocol for WBAN which tries to overcome the aforementioned challenges. We consider the use of multiple beam adaptive arrays (MBAA) at BAN Coordinator (BAN_C) node. When used as a BAN_C, an MBAA can successfully receive two or more overlapping packets at the same time. Each beam captures a different packet by automatically pointing its pattern toward one packet while annulling other contending packets. This paper describes how an MBAA can be integrated into a single hope star topology as a BAN_C. Simulation results show the performance of our proposed protocol. PMID:22346602

  17. Directional MAC Approach for Wireless Body Area Networks

    PubMed Central

    Hussain, Md. Asdaque; Alam, Md. Nasre; Kwak, Kyung Sup

    2011-01-01

    Wireless Body Area Networks (WBANs) designed for medical, sports, and entertainment applications, have drawn the attention of academia and industry alike. A WBAN is a special purpose network, designed to operate autonomously to connect various medical sensors and appliances, located inside and/or outside of a human body. This network enables physicians to remotely monitor vital signs of patients and provide real time feedback for medical diagnosis and consultations. The WBAN system can offer two significant advantages: patient mobility due to their use of portable monitoring devices and a location independent monitoring facility. With its appealing dimensions, it brings about a new set of challenges, which we do not normally consider in such small sensor networks. It requires a scalable network in terms of heterogeneous data traffic, low power consumption of sensor nodes, integration in and around the body networking and coexistence. This work presents a medium access control protocol for WBAN which tries to overcome the aforementioned challenges. We consider the use of multiple beam adaptive arrays (MBAA) at BAN Coordinator (BAN_C) node. When used as a BAN_C, an MBAA can successfully receive two or more overlapping packets at the same time. Each beam captures a different packet by automatically pointing its pattern toward one packet while annulling other contending packets. This paper describes how an MBAA can be integrated into a single hope star topology as a BAN_C. Simulation results show the performance of our proposed protocol. PMID:22346602

  18. Starburst Channels

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Figure 1

    Translucent carbon dioxide ice covers the polar regions of Mars seasonally. It is warmed and sublimates (evaporates) from below, and escaping gas carves a numerous channel morphologies.

    In this example (figure 1) the channels form a 'starburst' pattern, radiating out into feathery extensions. The center of the pattern is being buried with dust and new darker dust fans ring the outer edges. This may be an example of an expanding morphology, where new channels are formed as the older ones fill and are no longer efficiently channeling the subliming gas out.

    Observation Geometry Image PSP_003443_0980 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 21-Apr-2007. The complete image is centered at -81.8 degrees latitude, 76.2 degrees East longitude. The range to the target site was 247.1 km (154.4 miles). At this distance the image scale is 24.7 cm/pixel (with 1 x 1 binning) so objects 74 cm across are resolved. The image shown here has been map-projected to 25 cm/pixel. The image was taken at a local Mars time of 04:52 PM and the scene is illuminated from the west with a solar incidence angle of 71 degrees, thus the sun was about 19 degrees above the horizon. At a solar longitude of 223.4 degrees, the season on Mars is Northern Autumn.

  19. Hands-Off Time for Endotracheal Intubation during CPR Is Not Altered by the Use of the C-MAC Video-Laryngoscope Compared to Conventional Direct Laryngoscopy. A Randomized Crossover Manikin Study

    PubMed Central

    Schuerner, Philipp; Grande, Bastian; Piegeler, Tobias; Schlaepfer, Martin; Saager, Leif; Hutcherson, Matthew T.; Spahn, Donat R.

    2016-01-01

    Introduction Sufficient ventilation and oxygenation through proper airway management is essential in patients undergoing cardio-pulmonary resuscitation (CPR). Although widely discussed, securing the airway using an endotracheal tube is considered the standard of care. Endotracheal intubation may be challenging and causes prolonged interruption of chest compressions. Videolaryngoscopes have been introduced to better visualize the vocal cords and accelerate intubation, which makes endotracheal intubation much safer and may contribute to intubation success. Therefore, we aimed to compare hands-off time and intubation success of direct laryngoscopy with videolaryngoscopy (C-MAC, Karl Storz, Tuttlingen, Germany) in a randomized, cross-over manikin study. Methods Twenty-six anesthesia residents and twelve anesthesia consultants of the University Hospital Zurich were recruited through a voluntary enrolment. All participants performed endotracheal intubation using direct laryngoscopy and C-MAC in a random order during ongoing chest compressions. Participants were strictly advised to stop chest compression only if necessary. Results The median hands-off time was 1.9 seconds in direct laryngoscopy, compared to 3 seconds in the C-MAC group. In direct laryngoscopy 39 intubation attempts were recorded, resulting in an overall first intubation attempt success rate of 97%, compared to 38 intubation attempts and 100% overall first intubation attempt success rate in the C-MAC group. Conclusion As a conclusion, the results of our manikin-study demonstrate that video laryngoscopes might not be beneficial compared to conventional, direct laryngoscopy in easily accessible airways under CPR conditions and in experienced hands. The benefits of video laryngoscopes are of course more distinct in overcoming difficult airways, as it converts a potential “blind intubation” into an intubation under visual control. PMID:27195693

  20. Energy latency tradeoffs for medium access and sleep scheduling in wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Gang, Lu

    Wireless sensor networks are expected to be used in a wide range of applications from environment monitoring to event detection. The key challenge is to provide energy efficient communication; however, latency remains an important concern for many applications that require fast response. The central thesis of this work is that energy efficient medium access and sleep scheduling mechanisms can be designed without necessarily sacrificing application-specific latency performance. We validate this thesis through results from four case studies that cover various aspects of medium access and sleep scheduling design in wireless sensor networks. Our first effort, DMAC, is to design an adaptive low latency and energy efficient MAC for data gathering to reduce the sleep latency. We propose staggered schedule, duty cycle adaptation, data prediction and the use of more-to-send packets to enable seamless packet forwarding under varying traffic load and channel contentions. Simulation and experimental results show significant energy savings and latency reduction while ensuring high data reliability. The second research effort, DESS, investigates the problem of designing sleep schedules in arbitrary network communication topologies to minimize the worst case end-to-end latency (referred to as delay diameter). We develop a novel graph-theoretical formulation, derive and analyze optimal solutions for the tree and ring topologies and heuristics for arbitrary topologies. The third study addresses the problem of minimum latency joint scheduling and routing (MLSR). By constructing a novel delay graph, the optimal joint scheduling and routing can be solved by M node-disjoint paths algorithm under multiple channel model. We further extended the algorithm to handle dynamic traffic changes and topology changes. A heuristic solution is proposed for MLSR under single channel interference. In the fourth study, EEJSPC, we first formulate a fundamental optimization problem that provides tunable

  1. 78 FR 77074 - Accessibility of User Interfaces, and Video Programming Guides and Menus; Accessible Emergency...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-20

    ... COMMISSION 47 CFR Part 79 Accessibility of User Interfaces, and Video Programming Guides and Menus... authority for requiring MVPDs to ensure that video programming guides and menus that ] provide channel and... video programming guides and menus that provide channel and program information include high...

  2. Hemodialysis access procedures

    MedlinePlus

    Kidney failure - chronic-dialysis access; Renal failure - chronic-dialysis access; Chronic renal insufficiency-dialysis access; Chronic kidney failure-dialysis access; Chronic renal failure-dialysis access

  3. Revisiting the Phenice technique sex classification results reported by MacLaughlin and Bruce (1990).

    PubMed

    McFadden, Clare; Oxenham, Marc F

    2016-01-01

    Phenice (Am J Phys Anthropol 30 (1969):297-301) reported a success rate of 96% for his method of sex determination based on three morphological features of the pelvis. Numerous studies have tested and evaluated the method with affirmative results. The results of the study by MacLaughlin and Bruce (J Forensic Sci 35 (1990):1384-1392) were inconsistent with other studies, reporting far lower rates of accuracy and a greater degree of interobserver error. The authors believe that this may be the result of the inclusion of an "ambiguous" classification category. Revised modelling using forced classification of sex provides much higher classification rates with the implication that the poor results reported by MacLaughlin and Bruce were due to methodological error for the most part. PMID:26767498

  4. Acute lymphoblastic leukemia in a patient with MonoMAC syndrome/GATA2 haploinsufficiency.

    PubMed

    Koegel, Ashley K; Hofmann, Inga; Moffitt, Kristin; Degar, Barbara; Duncan, Christine; Tubman, Venée N

    2016-10-01

    Patients with GATA2 haploinsufficiency have a significant predisposition to developing cytopenias, unique infectious manifestations, and myelodysplastic syndrome/acute myeloid leukemia (MDS/AML). We report a unique case of a patient who presented with B-cell acute lymphoblastic leukemia (B-ALL) and was subsequently diagnosed with monocytopenia and mycobacterium avium complex (MonoMAC) syndrome/GATA2 haploinsufficiency. The development of MDS/AML in patients with GATA2 haploinsufficiency is well described, however, the development of ALL has not been reported in the literature. ALL may be associated with GATA2 haploinsufficiency. Clinicians should be attuned to the features of the MonoMAC syndrome in patients with ALL that would prompt additional testing and alter treatment. PMID:27232273

  5. Identification of MAC1: A Small Molecule That Rescues Spindle Bipolarity in Monastrol-Treated Cells.

    PubMed

    Al-Obaidi, Naowras; Mitchison, Timothy J; Crews, Craig M; Mayer, Thomas U

    2016-06-17

    The genetic integrity of each organism is intimately tied to the correct segregation of its genome during mitosis. Insights into the underlying mechanisms are fundamental for both basic research and the development of novel strategies to treat mitosis-relevant diseases such as cancer. Due to their fast mode of action, small molecules are invaluable tools to dissect mitosis. Yet, there is a great demand for novel antimitotic compounds. We performed a chemical genetic suppression screen to identify compounds that restore spindle bipolarity in cells treated with Monastrol, an inhibitor of the mitotic kinesin Eg5. We identified one compound-MAC1-that rescued spindle bipolarity in cells lacking Eg5 activity. Mechanistically, MAC1 induces the formation of additional microtubule nucleation centers, which allows kinesin Kif15-dependent bipolar spindle assembly in the absence of Eg5 activity. Thus, our chemical genetic suppression screen revealed novel unexpected insights into the mechanism of spindle assembly in mammalian cells. PMID:27121275

  6. Global Mobile Satellite Service Interference Analysis for the AeroMACS

    NASA Technical Reports Server (NTRS)

    Wilson, Jeffrey D.; Apaza, Rafael D.; Hall, Ward; Phillips, Brent

    2013-01-01

    The AeroMACS (Aeronautical Mobile Airport Communications System), which is based on the IEEE 802.16-2009 mobile wireless standard, is envisioned as the wireless network which will cover all areas of airport surfaces for next generation air transportation. It is expected to be implemented in the 5091-5150 MHz frequency band which is also occupied by mobile satellite service uplinks. Thus the AeroMACS must be designed to avoid interference with this incumbent service. Simulations using Visualyse software were performed utilizing a global database of 6207 airports. Variations in base station and subscriber antenna distribution and gain pattern were examined. Based on these simulations, recommendations for global airport base station and subscriber antenna power transmission limitations are provided.

  7. Application of the implicit MacCormack scheme to the parabolized Navier-Stokes equations

    NASA Technical Reports Server (NTRS)

    Lawrence, J. L.; Tannehill, J. C.; Chaussee, D. S.

    1984-01-01

    MacCormack's implicit finite-difference scheme was used to solve the two-dimensional parabolized Navier-Stokes (PNS) equations. This method for solving the PNS equations does not require the inversion of block tridiagonal systems of algebraic equations and permits the original explicit MacCormack scheme to be employed in those regions where implicit treatment is not needed. The advantages and disadvantages of the present adaptation are discussed in relation to those of the conventional Beam-Warming scheme for a flat plate boundary layer test case. Comparisons are made for accuracy, stability, computer time, computer storage, and ease of implementation. The present method was also applied to a second test case of hypersonic laminar flow over a 15% compression corner. The computed results compare favorably with experiment and a numerical solution of the complete Navier-Stokes equations.

  8. An FEC Adaptive Multicast MAC Protocol for Providing Reliability in WLANs

    NASA Astrophysics Data System (ADS)

    Basalamah, Anas; Sato, Takuro

    For wireless multicast applications like multimedia conferencing, voice over IP and video/audio streaming, a reliable transmission of packets within short delivery delay is needed. Moreover, reliability is crucial to the performance of error intolerant applications like file transfer, distributed computing, chat and whiteboard sharing. Forward Error Correction (FEC) is frequently used in wireless multicast to enhance Packet Error Rate (PER) performance, but cannot assure full reliability unless coupled with Automatic Repeat Request forming what is knows as Hybrid-ARQ. While reliable FEC can be deployed at different levels of the protocol stack, it cannot be deployed on the MAC layer of the unreliable IEEE802.11 WLAN due to its inability to exchange ACKs with multiple recipients. In this paper, we propose a Multicast MAC protocol that enhances WLAN reliability by using Adaptive FEC and study it's performance through mathematical analysis and simulation. Our results show that our protocol can deliver high reliability and throughput performance.

  9. Reliable Acquisition of RAM Dumps from Intel-Based Apple Mac Computers over FireWire

    NASA Astrophysics Data System (ADS)

    Gladyshev, Pavel; Almansoori, Afrah

    RAM content acquisition is an important step in live forensic analysis of computer systems. FireWire offers an attractive way to acquire RAM content of Apple Mac computers equipped with a FireWire connection. However, the existing techniques for doing so require substantial knowledge of the target computer configuration and cannot be used reliably on a previously unknown computer in a crime scene. This paper proposes a novel method for acquiring RAM content of Apple Mac computers over FireWire, which automatically discovers necessary information about the target computer and can be used in the crime scene setting. As an application of the developed method, the techniques for recovery of AOL Instant Messenger (AIM) conversation fragments from RAM dumps are also discussed in this paper.

  10. Pulmonary symptoms and diagnoses are associated with HIV in the MACS and WIHS cohorts

    PubMed Central

    2014-01-01

    Background Several lung diseases are increasingly recognized as comorbidities with HIV; however, few data exist related to the spectrum of respiratory symptoms, diagnostic testing, and diagnoses in the current HIV era. The objective of the study is to determine the impact of HIV on prevalence and incidence of respiratory disease in the current era of effective antiretroviral treatment. Methods A pulmonary-specific questionnaire was administered yearly for three years to participants in the Multicenter AIDS Cohort Study (MACS) and Women’s Interagency HIV Study (WIHS). Adjusted prevalence ratios for respiratory symptoms, testing, or diagnoses and adjusted incidence rate ratios for diagnoses in HIV-infected compared to HIV-uninfected participants were determined. Risk factors for outcomes in HIV-infected individuals were modeled. Results Baseline pulmonary questionnaires were completed by 907 HIV-infected and 989 HIV-uninfected participants in the MACS cohort and by 1405 HIV-infected and 571 HIV-uninfected participants in the WIHS cohort. In MACS, dyspnea, cough, wheezing, sleep apnea, and incident chronic obstructive pulmonary disease (COPD) were more common in HIV-infected participants. In WIHS, wheezing and sleep apnea were more common in HIV-infected participants. Smoking (MACS and WIHS) and greater body mass index (WIHS) were associated with more respiratory symptoms and diagnoses. While sputum studies, bronchoscopies, and chest computed tomography scans were more likely to be performed in HIV-infected participants, pulmonary function tests were no more common in HIV-infected individuals. Respiratory symptoms in HIV-infected individuals were associated with history of pneumonia, cardiovascular disease, or use of HAART. A diagnosis of asthma or COPD was associated with previous pneumonia. Conclusions In these two cohorts, HIV is an independent risk factor for several respiratory symptoms and pulmonary diseases including COPD and sleep apnea. Despite a higher

  11. Microfabricated Inserts for Magic Angle Coil Spinning (MACS) Wireless NMR Spectroscopy

    PubMed Central

    Badilita, Vlad; Fassbender, Birgit; Kratt, Kai; Wong, Alan; Bonhomme, Christian; Sakellariou, Dimitris; Korvink, Jan G.; Wallrabe, Ulrike

    2012-01-01

    This article describes the development and testing of the first automatically microfabricated probes to be used in conjunction with the magic angle coil spinning (MACS) NMR technique. NMR spectroscopy is a versatile technique for a large range of applications, but its intrinsically low sensitivity poses significant difficulties in analyzing mass- and volume-limited samples. The combination of microfabrication technology and MACS addresses several well-known NMR issues in a concerted manner for the first time: (i) reproducible wafer-scale fabrication of the first-in-kind on-chip LC microresonator for inductive coupling of the NMR signal and reliable exploitation of MACS capabilities; (ii) improving the sensitivity and the spectral resolution by simultaneous spinning the detection microcoil together with the sample at the “magic angle” of 54.74° with respect to the direction of the magnetic field (magic angle spinning – MAS), accompanied by the wireless signal transmission between the microcoil and the primary circuit of the NMR spectrometer; (iii) given the high spinning rates (tens of kHz) involved in the MAS methodology, the microfabricated inserts exhibit a clear kinematic advantage over their previously demonstrated counterparts due to the inherent capability to produce small radius cylindrical geometries, thus tremendously reducing the mechanical stress and tearing forces on the sample. In order to demonstrate the versatility of the microfabrication technology, we have designed MACS probes for various Larmor frequencies (194, 500 and 700 MHz) testing several samples such as water, Drosophila pupae, adamantane solid and LiCl at different magic angle spinning speeds. PMID:22936994

  12. Microfabricated inserts for magic angle coil spinning (MACS) wireless NMR spectroscopy.

    PubMed

    Badilita, Vlad; Fassbender, Birgit; Kratt, Kai; Wong, Alan; Bonhomme, Christian; Sakellariou, Dimitris; Korvink, Jan G; Wallrabe, Ulrike

    2012-01-01

    This article describes the development and testing of the first automatically microfabricated probes to be used in conjunction with the magic angle coil spinning (MACS) NMR technique. NMR spectroscopy is a versatile technique for a large range of applications, but its intrinsically low sensitivity poses significant difficulties in analyzing mass- and volume-limited samples. The combination of microfabrication technology and MACS addresses several well-known NMR issues in a concerted manner for the first time: (i) reproducible wafer-scale fabrication of the first-in-kind on-chip LC microresonator for inductive coupling of the NMR signal and reliable exploitation of MACS capabilities; (ii) improving the sensitivity and the spectral resolution by simultaneous spinning the detection microcoil together with the sample at the "magic angle" of 54.74° with respect to the direction of the magnetic field (magic angle spinning - MAS), accompanied by the wireless signal transmission between the microcoil and the primary circuit of the NMR spectrometer; (iii) given the high spinning rates (tens of kHz) involved in the MAS methodology, the microfabricated inserts exhibit a clear kinematic advantage over their previously demonstrated counterparts due to the inherent capability to produce small radius cylindrical geometries, thus tremendously reducing the mechanical stress and tearing forces on the sample. In order to demonstrate the versatility of the microfabrication technology, we have designed MACS probes for various Larmor frequencies (194, 500 and 700 MHz) testing several samples such as water, Drosophila pupae, adamantane solid and LiCl at different magic angle spinning speeds. PMID:22936994

  13. MACS: A Quest for the Most Massive Galaxy Clusters in the Universe

    NASA Astrophysics Data System (ADS)

    Ebeling, H.; Edge, A. C.; Henry, J. P.

    2001-06-01

    We describe the design and current status of a new X-ray cluster survey aimed at the compilation of a statistically complete sample of very X-ray luminous (and thus, by inference, massive), distant clusters of galaxies. The primary goal of the Massive Cluster Survey (MACS) is to increase the number of known massive clusters at z>0.3 from a handful to hundreds. Upon completion of the survey, the MACS cluster sample will greatly improve our ability to study quantitatively the physical and cosmological parameters driving cluster evolution at redshifts and luminosities poorly sampled by all existing surveys. To achieve these goals, we apply an X-ray flux and X-ray hardness ratio cut to select distant cluster candidates from the ROSAT Bright Source Catalogue. Starting from a list of more than 5000 X-ray sources within the survey area of 22,735 deg2, we use positional cross-correlations with public catalogs of Galactic and extragalactic objects, reference to Automated Plate Measuring Machine (APM) colors, visual inspection of Digitized Sky Survey images, extensive CCD imaging, and finally spectroscopic observations with the University of Hawaii's 2.2 m and the Keck 10 m telescopes to compile the final cluster sample. We discuss in detail the X-ray selection procedure and the resulting selection function and present model predictions for the number of distant clusters expected to emerge from MACS. At the time of this writing the MACS cluster sample comprises 101 spectroscopically confirmed clusters at 0.3<=z<=0.6 more than two-thirds of these are new discoveries. Our preliminary sample is already 15 times larger than that of the EMSS in the same redshift and X-ray luminosity range.

  14. Population studies I. The Bidelman-MacConnell ''weak-metal'' stars

    SciTech Connect

    Norris, J.; Bessell, M.S.; Pickles, A.J.

    1985-07-01

    We present BVRI and DDO photometry for 309 of the Bidelman-MacConnell ''weak-metal'' stars, together with radial velocities for most of the stars that have (Fe/H)< or =-0.8. Photometric taxonomy is used to classify the sample as giants, dwarfs, red horizontal-branch stars, UV-bright stars, etc., and various calibrations have been adopted to determine (Fe/H), M/sub V/, space motions, and orbital eccentricity e.

  15. 3. Credit PEM. Interior of Martinsburg plant showing two MacIntousch ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. Credit PEM. Interior of Martinsburg plant showing two MacIntousch Seymore steam engines and one Taylor steam engine belt driving (from let to right) a sperry 30 light, 220 Volt generator, a Westinghouse 900 light, 2200 Volt generator, a Ball 80 light are generator, and two Edison, 900 light, 220 Volt generators. Note switchboard to left. Photo c. 1896. - Dam No. 4 Hydroelectric Plant, Potomac River, Martinsburg, Berkeley County, WV

  16. Deformation, Failure, and Fatigue Life of SiC/Ti-15-3 Laminates Accurately Predicted by MAC/GMC

    NASA Technical Reports Server (NTRS)

    Bednarcyk, Brett A.; Arnold, Steven M.

    2002-01-01

    NASA Glenn Research Center's Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC) (ref.1) has been extended to enable fully coupled macro-micro deformation, failure, and fatigue life predictions for advanced metal matrix, ceramic matrix, and polymer matrix composites. Because of the multiaxial nature of the code's underlying micromechanics model, GMC--which allows the incorporation of complex local inelastic constitutive models--MAC/GMC finds its most important application in metal matrix composites, like the SiC/Ti-15-3 composite examined here. Furthermore, since GMC predicts the microscale fields within each constituent of the composite material, submodels for local effects such as fiber breakage, interfacial debonding, and matrix fatigue damage can and have been built into MAC/GMC. The present application of MAC/GMC highlights the combination of these features, which has enabled the accurate modeling of the deformation, failure, and life of titanium matrix composites.

  17. Wireless Fading Channel Models: From Classical to Stochastic Differential Equations

    SciTech Connect

    Olama, Mohammed M; Djouadi, Seddik M; Charalambous, Prof. Charalambos

    2010-01-01

    different protocols is nonuniform, it can even change the relative ranking among protocols for the same scenario. The importance of the physical layer is demonstrated by evaluating the Medium Access Control (MAC) performance. Most of the research conducted on wireless channel modeling deals mainly with deterministic wireless channel models. In these models, the speeds of the nodes are assumed to be constant and the statistical characteristics of the received signal are assumed to be fixed with time. But in reality, the propagation environment varies continuously due to mobility of the nodes at variable speeds and movement of objects or scatter across transmitters and receivers resulting in appearance or disappearance of existing paths from one instant to the next. As a result, the current models that assume fixed statistics are unable to capture and track complex time variations in the propagation environment.

  18. Sunyaev-Zeldovich Effect Imaging of MACS Galaxy Clusters at z greater than 0.5

    NASA Technical Reports Server (NTRS)

    Laroque, S. J.; Joy, M.; Carlstrom, J. E.; Ebeling, H.; Bonamente, M.; Dawson, K. S.; Edge, A.; Holzapfel, W. L.; Miller, A. D.; Nagai, D.; Six, N. Frank (Technical Monitor)

    2002-01-01

    We present 30 GHz interferometric SZE measurements of a redshift limited, X-ray selected cluster sample from the Massive Cluster Survey (MACS). All eight of the high redshift (z.0.5, dec greater than -15) galaxy clusters were detected. Additional observations were made at 4.8 GHz with the Very Large Array to help constrain the amount of point source contamination to the SZE decrements. From SZE data alone, we derive electron temperatures in the range 5.5-18.5 keV and total masses between 1.5 and 2.6 x 10 circumflex 14 M_sun within a 65 arcsecond radius for the eight clusters. Six of the clusters are MACS discoveries, while two (C10016+1609 and MS 0451.6-0305) were detected by previous X-ray observations and have been recently observed with the Chandra observatory. The X-ray derived temperatures and masses for Cl0016+ 1609 and MS 0451.6-0305 are in good agreement with the SZE-derived values. Strong detections of the SZE signal in this sample of MACS objects confirms that they are hot, massive clusters.

  19. Sunyaev-Zeldovich Effect Imaging of Macs Galaxy Clusters at =>0.5

    NASA Technical Reports Server (NTRS)

    LaRoque, Samuel; Joy, Marshall; Carlstrom, John E.; Ebeling, Harald; Bonamente, Massimiliano; Dawson, Kyle S.; Edge, Alastair; Holzapfel, William L.; Miller, Amber D.; Nagai, Daisuke

    2003-01-01

    We present 30 GHz interferometric Sunyaev-Zeldovich effect (SZE) measurements of a redshift-limited, X-ray-selected cluster sample from the Massive Cluster Survey (MACS). All eight of the high-redshift (z > 0.5, delta > -15 deg) galaxy clusters were detected. Additional observations were made at 4.8 GHz with the Very Large Array to help constrain the amount of point source contamination to the SZE decrements. From SZE data alone, we derive electron temperatures in the range 5.5-18.5 keV and total masses between 1.5 and 2.6 x 10(exp 14)/h solar masses within a 65 minute radius (0.28/h Mpc at z = 0.5) for the eight clusters. Six of the clusters are MACS discoveries, while two (C10016+1609 and MS 0451.6-0305) were detected by previous X-ray observations and have been recently observed with the Chandra observatory. The X-ray-derived temperatures and masses for C10016+1609 and MS 0451.6-0305 are in good agreement with the SZE derived values. Strong detections of the SZE signal in this sample of MACS objects confirm that they are hot, massive clusters.

  20. MacAlpine Hills 88104 and 88105 lunar highland meteorites: General description and consortium overview

    SciTech Connect

    Lindstrom, M.M. ); Schwarz, C.; Score, R. ); Mason, B. )

    1991-11-01

    MacAlpine Hills 88104 and 88105 are new lunar meteorites returned from Antarctica by the 1988-1989 US meteorite collection team. The two specimens were found in nearby locations and, based on field and laboratory evidence, are thought to be pieces of the same meteorite. MAC88105 is the largest lunar meteorite yet found (662 g). MAC88104/5 is an anorthositic breccia consisting of numerous small clasts in a glassy matrix. An origin on the Moon is supported by mineral, bulk, and oxygen isotope compositions. A consortium of twenty research groups has studied these meteorites. Samples were prepared at the NASA Johnson Space Center meteorite processing laboratory. Details of consortium plans and allocations are documented herein. A summary list of lunar meteorites and an overview of consortium research is presented. Discussions in this and the following consortium papers involve the issue of paired meteorites and paired ejecta, and what new information about the nature and evolution of the lunar crust is provided by the lunar meteorites.

  1. Cross-Cultural Adaptations of the MacArthur Competence Assessment Tool for Treatment in Iran

    PubMed Central

    Saber, Ali; Tabatabaei, Seyed Mahmoud; Akasheh, Goodarz; Sehat, Mojtaba; Zanjani, Zahra; Larijani, Bagher

    2016-01-01

    Background According to general ethical and legal principles, valid consent must be obtained before starting any procedure. Objectives Due to the lack of a standard tool for assessing patients’ capacity to consent to medical treatment in Iran, the present study was carried out aiming to devise a Persian version of a cross-cultural adaptation of the MacArthur competence assessment tool. Patients and Methods By reviewing different methods of cultural translation and adaptation for assessment tools, and due to the lack of consensus on its processes, we selected Wild’s model as one of the most comprehensive methods in this regard. Wild’s (2005) 10-stage model includes preparation, forward translation, reconciliation of the forward translation, back translation of reconciliation, back translation review, cognitive debriefing and cognitive review, and finalization, proofreading and final reporting. Using this model, we translated the MacArthur assessment tool and made it adaptable to Iranian patients. Results The MacArthur assessment tool is not dependent on any specific culture and language. As a result, if translation and its scientific adaptation are done based on an integrated and detailed model, the tool can be used for every culture and language. In other words, this tool is not culture-specific; so, it is applicable in cases where a translation is needed, and it can be culturally adapted to suit different societies. Conclusions In the present study, we are able to focus on and prove the efficacy and benefits of this measurement tool. PMID:27148503

  2. Nasotracheal intubation with MacGrath videolaryngoscope using Schroeder directional stylet: Case series

    PubMed Central

    Das, Bikramjit; Ahmed, Syed Moied; Raza, Nadeem

    2015-01-01

    Background and Aims: MacGrath videolaryngoscope is one of the recent videolaryngoscopes, which can be used to facilitate nasotracheal intubations using Scroeder directional stylet. Material and Methods: 15 patients, American Society of Anesthesiologists Grades I-II, undergoing tonsillectomy, requiring nasotracheal intubation were included. All patients were intubated with MacGrath videolaryngoscope and Schroeder stylet. Primary outcome measures were duration and ease of intubation. Overall success rate, number of attempts, modified Cormack-Lehane (C-L) grading, and complications were also recorded. Results: All 15 intubations were successful during first laryngoscopy attempt. C-L Grade I views were obtained in 14 patients (93%) and Grade II view in one patient (7%). The time required to obtain the best C-L view was 9.4 ± 1.5 s. The time taken to complete tracheal intubation was 34.27 ± 3.38 s. Average numerical rating scale for tracheal intubation was 8.7 ± 0.9. Minor complications occurred in four patients (26.7%). Conclusions: MacGrath videolaryngoscope produces excellent laryngoscopic views in patients with normal airways. Impaction of tracheal tube on posterior nasopharyngeal wall can be overcome by Schroeder stylet. PMID:25948909

  3. Flow variability and ongoing margin shifts on Bindschadler and MacAyeal Ice Streams, West Antarctica

    NASA Astrophysics Data System (ADS)

    Hulbe, C. L.; Scambos, T. A.; Klinger, M.; Fahnestock, M. A.

    2016-02-01

    Ice streams on the Ross Sea side of the West Antarctic Ice Sheet are known to experience flow variability on hourly, annual, and multicentury time scales. We report here on observations of flow variability at the decade scale on the Bindschadler and MacAyeal Ice Streams (BIS and MacIS). Our analysis makes use of archived ice velocity data and new mappings from composited Landsat 7 and Landsat 8 imagery that together span the interval from 1985 to 2014. Both ice streams speedup and slowdown in a range of about ±5 m a-2 over our various comparison intervals. The rates of change are variable in both time and space, and there is no evidence of external forcing at work across the two streams. Widespread changes are most likely linked to instability in the subglacial till and/or subglacial water flow. Sticky spots near the confluence of the two ice streams are loci for speed changes. These relatively young and slow-flowing features appear to be forcing shifts in margin position near the outlets of both streams. The margin jumps reduce the effective outlet widths of the streams by 20% and 30% on BIS and MacIS, respectively. Those magnitudes are similar to the outlet narrowing experienced by Kamb Ice Stream prior to its stagnation.

  4. The MacGyver effect: alive and well in health services research?

    PubMed Central

    2011-01-01

    Background In a manner similar to the television action hero MacGyver, health services researchers need to respond to the pressure of unpredictable demands and constrained time frames. The results are often both innovative and functional, with the creation of outputs that could not have been anticipated in the initial planning and design of the research. Discussion In the conduct of health services research many challenges to robust research processes are generated as a result of the interface between academic research, health policy and implementation agendas. Within a complex and rapidly evolving environment the task of the health services researcher is, therefore, to juggle sometimes contradictory pressures to produce valid results. Summary This paper identifies the MacGyver-type dilemmas which arise in health services research, wherein innovation may be called for, to maintain the intended scientific method and rigour. These 'MacGyver drivers' are framed as opposing issues from the perspective of both academic and public policy communities. The ideas expressed in this paper are illustrated by four examples from research projects positioned at the interface between public policy strategy and academia. PMID:21929826

  5. 42 CFR 405.1104 - Request for MAC review when an ALJ does not issue a decision timely.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Request for MAC review when an ALJ does not issue a... under § 405.1016 may request MAC review if— (1) The appellant files a written request with the ALJ to... escalation or 5 calendar days from the end of the applicable adjudication period set forth in § 405.1016....

  6. Pristane-induced granulocyte recruitment promotes phenotypic conversion of macrophages and protects against diffuse pulmonary hemorrhage in Mac-1 deficiency.

    PubMed

    Shi, Yiqin; Tsuboi, Naotake; Furuhashi, Kazuhiro; Du, Qiuna; Horinouchi, Asuka; Maeda, Kayaho; Kosugi, Tomoki; Matsuo, Seiichi; Maruyama, Shoichi

    2014-11-15

    Diffuse pulmonary hemorrhage (DPH) is an uncommon but critical complication of systemic lupus erythematosus. Peritoneal administration of 2,6,10,14-tetramethylpentadecane (pristane) can recapitulate a lupus-like syndrome in mice, which can develop into DPH within a few weeks, especially in C57BL/6 mice. Mac-1 (CD11b/CD18), a leukocyte adhesion molecule, is known to play a role in inflammation by regulating migration of leukocytes into injured tissue. In this study, we aimed to clarify the role of Mac-1 in pristane-induced DPH, using Mac-1(-/-) and wild-type (WT) mice on a C57BL/6 background. After pristane injection, Mac-1(-/-) mice showed reduced prevalence of DPH and attenuated peritonitis compared with WT mice. Analysis of the peritoneal lavage on days 5 and 10 after pristane treatment revealed increased numbers of eosinophils and alternatively activated macrophages, but decreased numbers of neutrophils and classically activated macrophages in Mac-1(-/-) mice compared with WT. Enhanced production of IL-4 and IL-13, both key mediators of macrophage polarization toward the mannose receptor(+) (MMR(+)) phenotype, was observed in the peritoneal cavity of Mac-1(-/-) mice. Depletion of neutrophils and eosinophils or adoptive transfer of classically activated macrophages resulted in the exacerbation of pristane-mediated DPH in both WT and Mac-1(-/-) mice. Moreover, peritoneal transfer of F4/80(high)MMR(+) alternatively activated macrophages successfully reduced the prevalence of DPH in WT mice. Collectively, Mac-1 promoted acute inflammatory responses in the peritoneal cavity and the lungs by downregulating granulocyte migration and subsequent phenotypic conversion of macrophages in a pristane-induced systemic lupus erythematosus model. PMID:25281714

  7. Heterogeneity of the Mac-1 expression on peripheral blood neutrophils in patients with different types of epithelial ovarian cancer.

    PubMed

    Bednarska, Katarzyna; Klink, Magdalena; Wilczyński, Jacek R; Szyłło, Krzysztof; Malinowski, Andrzej; Sułowska, Zofia; Nowak, Marek

    2016-02-01

    The expression level of Mac-1 on the surface of neutrophils is an important indicator of neutrophil activation. Under pathological conditions, Mac-1 is believed a key adhesion molecule that facilitates cancer progression and mediates the adhesion of tumour cells to the endothelium of blood vessels. Our previous findings indicated that circulating peripheral blood neutrophils in patients with advanced epithelial ovarian cancer (EOC) expressed enhanced levels of Mac-1, which was functionally associated with an increased adhesive function of neutrophils. The objective of the current study was to analyse whether the value of individual components of the differential white cell count, including the neutrophil and lymphocyte ratios, which are markers of blood neutrophil activation, might be associated with certain types of ovarian cancer. We showed the increase in Mac-1 expression along with a parallel decrease of L-selectin and PSGL-1 on peripheral blood neutrophils of patients with EOC of early and advanced FIGO stages, which indicates an activated state of neutrophils in comparison to neutrophils of individuals without cancer. Despite a significant difference between Mac-1 expression in patients with and without cancer, a dramatic increase in Mac-1 expression was observed in the blood of patients with undifferentiated carcinomas compared with patients with other histological types of EOC. Moreover, the expression level of Mac-1 correlated with the number of neutrophils in patients with serous, endometrioid and undifferentiated EOC. The results of an ROC analysis demonstrated that the patients with the undifferentiated type of EOC form a distinct group with regard to Mac-1 expression on blood neutrophils. The results suggested a diverse biological cadre of immune cells in patients with undifferentiated ovarian carcinomas compared with patients with other histological types of EOC. PMID:26563750

  8. An Energy-Efficient MAC Protocol Using Dynamic Queue Management for Delay-Tolerant Mobile Sensor Networks

    PubMed Central

    Li, Jie; Li, Qiyue; Qu, Yugui; Zhao, Baohua

    2011-01-01

    Conventional MAC protocols for wireless sensor network perform poorly when faced with a delay-tolerant mobile network environment. Characterized by a highly dynamic and sparse topology, poor network connectivity as well as data delay-tolerance, delay-tolerant mobile sensor networks exacerbate the severe power constraints and memory limitations of nodes. This paper proposes an energy-efficient MAC protocol using dynamic queue management (EQ-MAC) for power saving and data queue management. Via data transfers initiated by the target sink and the use of a dynamic queue management strategy based on priority, EQ-MAC effectively avoids untargeted transfers, increases the chance of successful data transmission, and makes useful data reach the target terminal in a timely manner. Experimental results show that EQ-MAC has high energy efficiency in comparison with a conventional MAC protocol. It also achieves a 46% decrease in packet drop probability, 79% increase in system throughput, and 25% decrease in mean packet delay. PMID:22319385

  9. An energy-efficient MAC protocol using dynamic queue management for delay-tolerant mobile sensor networks.

    PubMed

    Li, Jie; Li, Qiyue; Qu, Yugui; Zhao, Baohua

    2011-01-01

    Conventional MAC protocols for wireless sensor network perform poorly when faced with a delay-tolerant mobile network environment. Characterized by a highly dynamic and sparse topology, poor network connectivity as well as data delay-tolerance, delay-tolerant mobile sensor networks exacerbate the severe power constraints and memory limitations of nodes. This paper proposes an energy-efficient MAC protocol using dynamic queue management (EQ-MAC) for power saving and data queue management. Via data transfers initiated by the target sink and the use of a dynamic queue management strategy based on priority, EQ-MAC effectively avoids untargeted transfers, increases the chance of successful data transmission, and makes useful data reach the target terminal in a timely manner. Experimental results show that EQ-MAC has high energy efficiency in comparison with a conventional MAC protocol. It also achieves a 46% decrease in packet drop probability, 79% increase in system throughput, and 25% decrease in mean packet delay. PMID:22319385

  10. Quantum internet using code division multiple access.

    PubMed

    Zhang, Jing; Liu, Yu-xi; Ozdemir, Sahin Kaya; Wu, Re-Bing; Gao, Feifei; Wang, Xiang-Bin; Yang, Lan; Nori, Franco

    2013-01-01

    A crucial open problem inS large-scale quantum networks is how to efficiently transmit quantum data among many pairs of users via a common data-transmission medium. We propose a solution by developing a quantum code division multiple access (q-CDMA) approach in which quantum information is chaotically encoded to spread its spectral content, and then decoded via chaos synchronization to separate different sender-receiver pairs. In comparison to other existing approaches, such as frequency division multiple access (FDMA), the proposed q-CDMA can greatly increase the information rates per channel used, especially for very noisy quantum channels. PMID:23860488

  11. Quantum internet using code division multiple access

    NASA Astrophysics Data System (ADS)

    Zhang, Jing; Liu, Yu-Xi; Özdemir, Şahin Kaya; Wu, Re-Bing; Gao, Feifei; Wang, Xiang-Bin; Yang, Lan; Nori, Franco

    2013-07-01

    A crucial open problem inS large-scale quantum networks is how to efficiently transmit quantum data among many pairs of users via a common data-transmission medium. We propose a solution by developing a quantum code division multiple access (q-CDMA) approach in which quantum information is chaotically encoded to spread its spectral content, and then decoded via chaos synchronization to separate different sender-receiver pairs. In comparison to other existing approaches, such as frequency division multiple access (FDMA), the proposed q-CDMA can greatly increase the information rates per channel used, especially for very noisy quantum channels.

  12. Human-induced stream channel abandonment/capture and filling of floodplain channels within the Atchafalaya River Basin, Louisiana

    USGS Publications Warehouse

    Kroes, Daniel E.; Kraemer, Thomas F.

    2013-01-01

    The Atchafalaya River Basin is a distributary system of the Mississippi River containing the largest riparian area in the lower Mississippi River Valley and the largest remaining forested bottomland in North America. Reductions in the area of open water in the Atchafalaya have been occurring over the last 100 years, and many historical waterways are increasingly filled by sediment. This study examines two cases of swamp channels (3/s) that are filling and becoming unnavigable as a result of high sediment loads and slow water velocities. The water velocities in natural bayous are further reduced because of flow capture by channels constructed for access. Bathymetry, flow, suspended sediment, deposited bottom-material, isotopes, and photointerpretation were used to characterize the channel fill. On average, water flowing through these two channels lost 23% of the suspended sediment load in the studied reaches. Along one of the studied reaches, two constructed access channels diverted significant flow out of the primary channel and into the adjacent swamp. Immediately downstream of each of the two access channels, the cross-sectional area of the studied channel was reduced. Isotopic analyses of bottom-material cores indicate that bed filling has been rapid and occurred after detectable levels of Cesium-137 were no longer being deposited. Interpretation of aerial photography indicates that water is bypassing the primary channels in favor of the more hydraulically efficient access channels, resulting in low or no-velocity flow conditions in the primary channel. These swamp channel conditions are typical in the Atchafalaya River Basin where relict large channel dimensions result in flow velocities that are normally too low to carry fine-grained sediment. Constructed channels increase the rate of natural channel avulsion and abandonment as a result of flow capture.

  13. Quantum channel capacities: Multiparty communication

    NASA Astrophysics Data System (ADS)

    Demianowicz, Maciej; Horodecki, Paweł

    2006-10-01

    We analyze different aspects of multiparty communication over quantum memoryless channels and generalize some of the key results known from bipartite channels to the multiparty scenario. In particular, we introduce multiparty versions of subspace and entanglement transmission fidelities. We also provide alternative, local, versions of fidelities and show their equivalence to the global ones in context of capacity regions defined. An equivalence of two different capacity notions with respect to two types of fidelities is proven. In analogy to the bipartite case it is shown, via sufficiency of isometric encoding theorem, that additional classical forward side channel does not increase capacity region of any quantum channel with k senders and m receivers which represents a compact unit of general quantum networks theory. The result proves that recently provided capacity region of a multiple access channel [M. Horodecki , Nature 436, 673 (2005); J. Yard , e-print quant-ph/0501045], is optimal also in a scenario of an additional support of forward classical communication.

  14. Unsteady compressible flows in channel with varying walls

    NASA Astrophysics Data System (ADS)

    Pořízková, P.; Kozel, K.; Horáček, J.

    2014-03-01

    This study deals with numerical solution of a 2D and 3D unsteady flows of a compressible viscous fluid in 2D and 3D channel for low inlet airflow velocity. The unsteadiness of the flow is caused by a prescribed periodic motion of a part of the channel wall, nearly closing the channel during oscillations. The channels shape is a simplified geometry of the glottal space in the human vocal tract. Goal is numerical simulation of flow in the channels which involves attributes of real flow causing acoustic perturbations. The system of Navier-Stokes equations closed with static pressure expression for ideal gas describes the unsteady laminar flow of compressible viscous fluid. The numerical solution is implemented using the finite volume method and the predictor-corrector MacCormack scheme with artificial viscosity using a grid of quadrilateral cells. The unsteady grid of quadrilateral cells is considered in the form of conservation laws using Arbitrary Lagrangian-Eulerian method. The application of developed method for numerical simulations of flow fields in the 2D and 3D channels, acquired from a developed program, are presented for inlet velocity u=4.12 m/s, inlet Reynolds number Re=4481 and the wall motion frequency 100 Hz.

  15. Characterization and Conductivity Behavior of Magnetic Activated Carbon (MAC) from FeCl2.4H2O-Containing Carbon

    NASA Astrophysics Data System (ADS)

    Aripin, Department Of Physics, Faculty Of Mathematics; Natural Science, Haluoleo University, Kampus Bumi Tridharma Anduonohu Kendari 93232 Indonesia

    2007-05-01

    Activated carbons (AC) and magnetic-containing activated carbons (MAC) have been synthesized using coconut shells as carbon sources and FeCl2.4H2O as magnetic precursor. The samples were characterized by nitrogen sorption, XRD, and FTIR. The BET surface area and total pore volume of MAC increase as the temperature increased. AC has XRD peaks, which evidences an amorphous carbon framework and MAC shows that this material consists of an organized carbon with the nanocrystalline magnetite embedded in its structure. The FTIR spectrum of MAC shows that carboxyl groups decreased as the temperature increased. Absorption bands of MAC shows the stretching and torsional vibration modes of the magnetite Fe-O bond in tetrahedral and octahedral sites, respectively. The electrical conductivity studies showed that conductivity of MAC is more than the AC due to structural properties of carbons exists on a framework containing metal structures.

  16. Data Processing for NASA's TDRSS DAMA Channel

    NASA Technical Reports Server (NTRS)

    Long, Christopher C.; Horan, Stephen

    1996-01-01

    A concept for the addition of a Demand Assignment Multiple Access (DAMA) service to NASA's current Space Network (SN) is developed. Specifically, the design of a receiver for the DAMA channel is outlined. Also, an outline of the procedures taken to process the received service request is presented. The modifications to the (SN) system are minimal. The post reception processing is accomplished using standard commercial off the shelf (COTS) packages. The result is a random access system capable of receiving requests for service.

  17. MacMS: A Mass Spectrometer Simulator: Abstract of Issue 9906M

    NASA Astrophysics Data System (ADS)

    Bigger, Stephen W.; Craig, Robert A.

    1999-10-01

    MacMS is a program for Mac-OS compatible computers that simulates a magnetic sector mass spectrometer (1-4) designed to operate in the mass-to-charge (m/z) ratio range of 1-200 amu. MacMS has two operational modules. The first module (see Figure 1) is called the "Path" module and enables the user to quantitatively examine the trajectory of an ion of given m/z ratio in the electric and magnetic fields of the simulated "instrument". By systematically measuring a series of trajectories of different ions under different electric and magnetic field conditions, the user can determine how the resolution of the "instrument" is affected by these experimentally variable parameters. The user can thus choose suitable instrumental conditions for scanning a given m/z ratio range with good separation between the peaks. The second module (see Figure 2) is called as the "Spectrometer" module and enables the user to record, under any chosen instrumental conditions, the mass spectrum of (i) the instrumental background, (ii) neon, (iii) methane, or (iv) the parent ion of carbon tetrachloride. Both voltage scanning and magnetic scanning are possible (5). A hard copy of any mass spectrum that has been recorded can also be obtained. MacMS can read ASCII data files containing mass spectral information of compounds other than those that are "built-in" to the simulator. The appropriate format for creating such data files is described in the program documentation. There are a number of instructional exercises that can be conducted using the mass spectral information contained within the simulator. These are included in the program documentation. For example, the intensities of the 20Ne+, 21Ne+, and 22Ne+ species can be determined from hard copies of mass spectra of neon that are obtained under different instrumental sensitivities. The relative abundances of the three isotopes of neon can thus be calculated and compared with the literature values (6). The simulator also includes adjustable

  18. HCN1 Channels Contribute to the Effects of Amnesia and Hypnosis But Not Immobility of Volatile Anesthetics

    PubMed Central

    Liu, Jin; Ke, Bowen; Wang, Xiaojia; Li, Fengshan; Li, Tao; Bayliss, Douglas A.; Chen, Xiangdong

    2015-01-01

    Background HCN1 channels have been identified as targets of ketamine to produce hypnosis. Volatile anesthetics also inhibit HCN1 channels. However, the effects of HCN1 channels on volatile anesthetics in vivo is still elusive. This study uses global and conditional HCN1 knockout mice to evaluate how HCN1 channels affect the actions of volatile anesthetics. Methods Minimum alveolar concentrations (MAC) of isoflurane and sevoflurane that induced immobility (MAC of immobility) and/or hypnosis (MAC of hypnosis) were determined in wild-type (WT) mice, global HCN1 channel knockout mice (HCN1−/−), floxed HCN1 channel gene (HCN1f/f) mice and forebrain-selective HCN1 channel knockout (HCN1f/f: cre) mice. Immobility of mice was defined as no purposeful reactions to tail-clamping stimulus and hypnosis was defined as loss of righting reflex (LORR). The amnestic effects of isoflurane and sevoflurane were evaluated by fear-potentiated startle in these four strains of mice. Results All MAC values were expressed as mean ± SEM. For MAC of immobility of isoflurane, no significant difference was found among wild-type, HCN1−/−, HCN1f/f and HCN1f/f: cre mice (all ~1.24-1.29% isoflurane). For both HCN1−/− and HCN1f/f: cre mice, the MAC of hypnosis for isoflurane (each ~1.05% isoflurane) were significantly increased over their nonknockout controls: HCN1−/− vs. wild-type (0.86±0.03%, P<0.001) and HCN1f/f: cre vs. HCN1f/f mice (0.84±0.03%, P<0.001); no significant difference was found between HCN1−/− and HCN1f/f: cre mice. For MAC of immobility of sevoflurane, no significant difference was found among wild-type, HCN1−/−, HCN1f/f and HCN1f/f: cre mice (all ~2.6-2.7% sevoflurane). For both HCN1−/− and HCN1f/f: cre mice, the MAC of hypnosis for sevoflurane (each ~1.90% sevoflurane) was significantly increased over their nonknockout controls: HCN1−/− vs. wild-type (1.58±0.05%, P<0.001) and HCN1f/f: cre vs. HCN1f/f mice (1.56±0.05%, P<0.001). No significant

  19. The roles of K(+) channels in cancer.

    PubMed

    Pardo, Luis A; Stühmer, Walter

    2014-01-01

    Potassium channels are transmembrane proteins that selectively facilitate the flow of potassium ions down an electrochemical gradient. These molecules have been studied in great detail in the context of cell excitability, but their roles in less cell type-specific functions, such as cell proliferation, angiogenesis or cell migration, have only recently been assessed. Moreover, the importance of these channels for tumour biology has become evident. This, coupled with the fact that they are accessible proteins and that their pharmacology is well characterized, has increased the interest in investigating potassium channels as therapeutic targets in cancer patients. PMID:24336491

  20. Proposal to elevate Mycobacterium avium complex ITS sequevar MAC-Q to Mycobacterium vulneris sp. nov.

    PubMed

    van Ingen, J; Boeree, M J; Kösters, K; Wieland, A; Tortoli, E; Dekhuijzen, P N R; van Soolingen, D

    2009-09-01

    The Mycobacterium avium complex (MAC) consists of four recognized species, Mycobacterium avium, Mycobacterium colombiense, Mycobacterium intracellulare and Mycobacterium chimaera, and a variety of other strains that may be members of undescribed taxa. We report on two isolates of a scotochromogenic, slowly growing, non-tuberculous Mycobacterium species within the M. avium complex from a lymph node and an infected wound after a dogbite of separate patients in The Netherlands. The extrapulmonary infections in immunocompetent patients suggested a high level of virulence. These isolates were characterized by a unique nucleotide sequence in the 16S rRNA gene, 99% similar to Mycobacterium colombiense, and the MAC-Q 16S-23S internal transcribed spacer (ITS) sequence. Sequence analyses of the hsp65 gene revealed 97% similarity to M. avium. The rpoB gene sequence was 98% similar to M. colombiense. Phenotypically, the scotochromogenicity, positive semi-quantitative catalase and heat-stable catalase tests, negative tellurite reductase and urease tests and susceptibility to hydroxylamine and oleic acid set these isolates apart from related species. High-performance liquid chromatography analysis of cell-wall mycolic acid content revealed a unique pattern, related to that of M. avium and M. colombiense. Together, these findings supported a separate species status within the Mycobacterium avium complex. We propose elevation of scotochromogenic M. avium complex strains sharing this 16S gene and MAC-Q ITS sequence to separate species status, for which the name Mycobacterium vulneris sp. nov. is proposed. The type strain is NLA000700772T (=DSM 45247T=CIP 109859T). PMID:19620376

  1. FACS and MACS sorting strategies to isolate and enrich human spermatogonial stem cells

    PubMed Central

    Valli, Hanna; Sukhwani, Meena; Dovey, Serena L.; Peters, Karen A.; Donohue, Julia; Castro, Carlos A.; Chu, Tianjiao; Marshall, Gary R.; Orwig, Kyle E.

    2014-01-01

    Objective Determine the molecular characteristics of human spermatogonia and optimize methods to enrich spermatogonial stem cells (SSCs). Design Laboratory study using human tissues Setting Research institute Patient(s)/Animal(s) Normal adult human testicular tissue. Interventions Human testicular tissue was fixed or digested with enzymes to produce a cell suspension. Human testis cells were fractionated by FACS and MACS. Main Outcome Measure(s) Immunostaining for selected markers, human-to-nude mouse xenotransplantation assay. Results Immunohistochemistry co-staining revealed the relative expression patterns of SALL4, UTF1, ZBTB16, UCHL1 and ENO2 in human undifferentiated spermatogonia as well as the extent of overlap with the differentiation marker, KIT. Whole mount analyses revealed that human undifferentiated spermatogonia (UCHL1+) were typically arranged in clones of 1–4 cells while differentiated spermatogonia (KIT+) were typically arranged in clones of 8 or more cells. The ratio of undifferentiated to differentiated spermatogonia is greater in humans than in rodents. SSC colonizing activity was enriched in the THY1dim and ITGA6+ fractions of human testes sorted by FACS. ITGA6 was effective for sorting human SSCs by MACS; THY1 and EPCAM were not. Conclusions Human spermatogonial differentiation correlates with increased clone size and onset of KIT expression, similar to rodents. The undifferentiated to differentiated developmental dynamics in human spermatogonia is different than rodents. THY1, ITGA6 and EPCAM can be used to enrich human SSC colonizing activity by FACS, but only ITGA6 is amenable to high throughput sorting by MACS. PMID:24890267

  2. Infrared Grism Confirmation of a Strongly Lensed z ~ 11 Candidate: MACS0647-JD

    NASA Astrophysics Data System (ADS)

    Coe, Dan

    2013-10-01

    The first galaxies are the frontier of extragalactic astronomy. How and when did they form, and how did they contribute to reionization? Gravitational lensing has enabled efficient discovery of high-redshift galaxies including MACS0647-JD at z ~ 10.8 (420 Myr after the Big Bang), a strong candidate for the most distant galaxy yet known. This discovery by the CLASH Multi-Cycle Treasury program is consistent with expectations extrapolated from lower redshifts (4 < z < 8). The evolving luminosity function fit to these data includes sufficient numbers of faint galaxies at early times to reionize the universe. However, the discovery of MACS0647-JD is in tension with lower number densities of z > 9 candidates identified in deep field observations including the UDF. These field studies suggest z > 9 galaxies were building up in numbers much more rapidly than observed at later times. Confirmation of the z ~ 10.8 candidate is therefore paramount to our understanding of early galaxy evolution and reionization. All three strongly lensed images of MACS0647-JD are significantly detected in two HST filters (F140W and F160W). Lower redshift objects have been ruled out with high confidence, and the redshift is corroborated by our lens modeling. The strong lensing magnification provides us with a rare opportunity to confirm such a high redshift. We propose to do so with ten orbits of WFC3/IR G141 grism observations. Two orbits of F140W imaging are also required for calibration. As the first ever HST IR grism observations of a z < 1 cluster, this program will serve as an important pathfinder for future IR grism observations of lensed fields with HST and with the James Webb Space Telescope.

  3. Supervised fully polarimetric classification of the Black Forest test site: From MAESTROI to MAC Europe

    NASA Technical Reports Server (NTRS)

    Degrandi, G.; Lavalle, C.; Degroof, H.; Sieber, A.

    1992-01-01

    A study on the performance of a supervised fully polarimetric maximum likelihood classifier for synthetic aperture radar (SAR) data when applied to a specific classification context: forest classification based on age classes and in the presence of a sloping terrain is presented. For the experimental part, the polarimetric AIRSAR data at P, L, and C-band, acquired over the German Black Forest near Freiburg in the frame of the 1989 MAESTRO-1 campaign and the 1991 MAC Europe campaign was used, MAESTRO-1 with an ESA/JRC sponsored campaign, and MAC Europe (Multi-sensor Aircraft Campaign); in both cases the multi-frequency polarimetric JPL Airborne Synthetic Aperture Radar (AIRSAR) radar was flown over a number of European test sites. The study is structured as follows. At first, the general characteristics of the classifier and the dependencies from some parameters, like frequency bands, feature vector, calibration, using test areas lying on a flat terrain are investigated. Once it is determined the optimal conditions for the classifier performance, we then move on to the study of the slope effect. The bulk of this work is performed using the Maestrol data set. Next the classifier performance with the MAC Europe data is considered. The study is divided into two stages: first some of the tests done on the Maestro data are repeated, to highlight the improvements due to the new processing scheme that delivers 16 look data. Second we experiment with multi images classification with two goals: to assess the possibility of using a training set measured from one image to classify areas in different images; and to classify areas on critical slopes using different viewing angles. The main points of the study are listed and some of the results obtained so far are highlighted.

  4. Maize multiple archesporial cells 1 (mac1), an ortholog of rice TDL1A, modulates cell proliferation and identity in early anther development.

    PubMed

    Wang, Chung-Ju Rachel; Nan, Guo-Ling; Kelliher, Timothy; Timofejeva, Ljudmilla; Vernoud, Vanessa; Golubovskaya, Inna N; Harper, Lisa; Egger, Rachel; Walbot, Virginia; Cande, W Zacheus

    2012-07-01

    To ensure fertility, complex somatic and germinal cell proliferation and differentiation programs must be executed in flowers. Loss-of-function of the maize multiple archesporial cells 1 (mac1) gene increases the meiotically competent population and ablates specification of somatic wall layers in anthers. We report the cloning of mac1, which is the ortholog of rice TDL1A. Contrary to prior studies in rice and Arabidopsis in which mac1-like genes were inferred to act late to suppress trans-differentiation of somatic tapetal cells into meiocytes, we find that mac1 anthers contain excess archesporial (AR) cells that proliferate at least twofold more rapidly than normal prior to tapetal specification, suggesting that MAC1 regulates cell proliferation. mac1 transcript is abundant in immature anthers and roots. By immunolocalization, MAC1 protein accumulates preferentially in AR cells with a declining radial gradient that could result from diffusion. By transient expression in onion epidermis, we demonstrate experimentally that MAC1 is secreted, confirming that the predicted signal peptide domain in MAC1 leads to secretion. Insights from cytology and double-mutant studies with ameiotic1 and absence of first division1 mutants confirm that MAC1 does not affect meiotic cell fate; it also operates independently of an epidermal, Ocl4-dependent pathway that regulates proliferation of subepidermal cells. MAC1 both suppresses excess AR proliferation and is responsible for triggering periclinal division of subepidermal cells. We discuss how MAC1 can coordinate the temporal and spatial pattern of cell proliferation in maize anthers. PMID:22696296

  5. Maize multiple archesporial cells 1 (mac1), an ortholog of rice TDL1A, modulates cell proliferation and identity in early anther development

    PubMed Central

    Wang, Chung-Ju Rachel; Nan, Guo-Ling; Kelliher, Timothy; Timofejeva, Ljudmilla; Vernoud, Vanessa; Golubovskaya, Inna N.; Harper, Lisa; Egger, Rachel; Walbot, Virginia; Cande, W. Zacheus

    2012-01-01

    To ensure fertility, complex somatic and germinal cell proliferation and differentiation programs must be executed in flowers. Loss-of-function of the maize multiple archesporial cells 1 (mac1) gene increases the meiotically competent population and ablates specification of somatic wall layers in anthers. We report the cloning of mac1, which is the ortholog of rice TDL1A. Contrary to prior studies in rice and Arabidopsis in which mac1-like genes were inferred to act late to suppress trans-differentiation of somatic tapetal cells into meiocytes, we find that mac1 anthers contain excess archesporial (AR) cells that proliferate at least twofold more rapidly than normal prior to tapetal specification, suggesting that MAC1 regulates cell proliferation. mac1 transcript is abundant in immature anthers and roots. By immunolocalization, MAC1 protein accumulates preferentially in AR cells with a declining radial gradient that could result from diffusion. By transient expression in onion epidermis, we demonstrate experimentally that MAC1 is secreted, confirming that the predicted signal peptide domain in MAC1 leads to secretion. Insights from cytology and double-mutant studies with ameiotic1 and absence of first division1 mutants confirm that MAC1 does not affect meiotic cell fate; it also operates independently of an epidermal, Ocl4-dependent pathway that regulates proliferation of subepidermal cells. MAC1 both suppresses excess AR proliferation and is responsible for triggering periclinal division of subepidermal cells. We discuss how MAC1 can coordinate the temporal and spatial pattern of cell proliferation in maize anthers. PMID:22696296

  6. 33 CFR 334.630 - Tampa Bay south of MacDill Air Force Base, Fla.; small-arms firing range and aircraft jettison, U...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base...″, longitude 82°33′02.44″; and thence to a point on the shore line of MacDill Air Force Base at latitude...

  7. 33 CFR 334.630 - Tampa Bay south of MacDill Air Force Base, Fla.; small-arms firing range and aircraft jettison, U...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base...″, longitude 82°33′02.44″; and thence to a point on the shore line of MacDill Air Force Base at latitude...

  8. 33 CFR 334.630 - Tampa Bay south of MacDill Air Force Base, Fla.; small-arms firing range and aircraft jettison, U...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base...″, longitude 82°33′02.44″; and thence to a point on the shore line of MacDill Air Force Base at latitude...

  9. 33 CFR 334.630 - Tampa Bay south of MacDill Air Force Base, Fla.; small-arms firing range and aircraft jettison, U...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base...″, longitude 82°33′02.44″; and thence to a point on the shore line of MacDill Air Force Base at latitude...

  10. 33 CFR 334.630 - Tampa Bay south of MacDill Air Force Base, Fla.; small-arms firing range and aircraft jettison, U...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base... Force Base, Fla.; small-arms firing range and aircraft jettison, U.S. Air Force, MacDill Air Force Base...″, longitude 82°33′02.44″; and thence to a point on the shore line of MacDill Air Force Base at latitude...

  11. Cuff inflation to aid nasotracheal intubation using the C-MAC videolaryngoscope.

    PubMed

    Baddoo, H K; Phillips, B J

    2011-06-01

    A preliminary report is presented of a technique for using the C-MAC videolaryngoscope to carry out nasopharyngeal intubations. The main thrust of the technique is that cuff inflation of the endotracheal tube is used to lift the endotracheal tube off the posterior pharyngeal wall and thus direct it towards the glottis. The technique was used successfully in 5 consecutive patients needing nasotracheal intubation. Indeed a couple of these patients might have been difficult to intubate using conventional laryngoscopy. The full technique is described together with pictures at the various stages of intubation. PMID:21857727

  12. 7 years of MacGyver sessions at EGU and AGU: what happened?

    NASA Astrophysics Data System (ADS)

    Hut, Rolf; Selker, John; Weijs, Steven; Luxemburg, Wim; Wickert, Andy; Blume, Theresa; Bamburger, Jan; Stoof, Cathelijne; Tauro, Flavia

    2016-04-01

    The session that this poster is in, the: "Self-made sensors and unintended use of measurement equipment", also known as the "MacGyver-session" has had 7 years of scientists contributing their self made devices, hacks and solutions with the hydrological community. In 2009, the first session was held at the AGU fall meeting and since 2011 a session is also organised at the EGU General Assembly. On this poster, and in the accompanying review paper, we will present an overview of the work presented in the last 7 years, cataloging the work of the inventive scientists who have contributed to these successful, and above all: fun, sessions.

  13. A click strategy for the immobilization of MacMillan organocatalysts onto polymers and magnetic nanoparticles.

    PubMed

    Riente, Paola; Yadav, Jagjit; Pericàs, Miquel A

    2012-07-20

    A chemically modified, first generation MacMillan imidazolidin-4-one has been anchored onto 1% DVB Merrifield resin and Fe3O4 (5.3 ± 1.4 nm) magnetic nanoparticles through copper-catalyzed alkyne azide cycloaddition (CuAAC) reactions. The resulting immobilized catalysts have been successfully used in the asymmetric Friedel-Crafts alkylation of N-substituted pyrroles with α,β-unsaturated aldehydes. The PS-supported catalyst (B) showed higher catalytic activity and enantioselectivity, while the MNP-supported one (A) showed higher recyclability and could be used in a sequential process with intermediate magnetic decantation. PMID:22758605

  14. Coal-Mac, Inc. Phoenix No. 1 mine provides wildlife haven. 2007 Wildlife West Virginia Award

    SciTech Connect

    Skinner, A.

    2007-07-15

    Coal Mac, Inc.'s Harless Wood Industrial Park off Holden 22 Mines Road in Logan Country, West Virginia is an award-winning reclamation site in the mountains frequented by geese, wild turkey, deer and black bears. Orchard grass and rye is a temporary cover for the timothy, clover and other seedlings. The area was mined several years ago. Some 40,000-50,000 tons of coal per month are surfaced mined with the current permit that takes in 1,500-2,000 acres. After removing the coal, valleys are backfilled as part of the mining and reclamation plan. 10 photos.

  15. Rheumatologic manifestations of the "MonoMAC" syndrome. a systematic review.

    PubMed

    Johnson, Jennifer A; Yu, Steven S; Elist, Michael; Arkfeld, Daniel; Panush, Richard S

    2015-09-01

    MonoMAC syndrome is characterized by monocytopenia with susceptibility to nontuberculous mycobacterial infections. First recognized in 2011, it is caused by GATA2 mutations and can manifest as disseminated mycobacterial, fungal, and viral infections. While mortality rates for this disorder have been high, it has recently been successfully treated with haploidentical allogeneic stem cell transplant. Since approximately one third of patients may have rheumatologic symptoms, such as erythema nodosum, panniculitis, or arthralgias, rheumatologists may expect to encounter this newly described entity with increasing frequency. PMID:25739845

  16. Results of exploratory drilling at Point MacKenzie, Alaska, 1981

    USGS Publications Warehouse

    Patrick, Leslie

    1981-01-01

    The Matanuska-Susitna Borough anticipates industrial development near Point MacKenzie, Alaska. Because little hydrologic information is available for the area, the Borough contracted for the drilling of two test wells. It was found that: Both wells penetrated unconsolidated stratified clay, silt, sand, and gravel; each well penetrated a shallow unconfined and deeper confined aquifers; the water levels in the wells rise and fall with the tide; the chemical analyses indicate that the water quality meets the Alaska Drinking Water Standards, except for slightly high levels of manganese and pH; and the potential for saltwater intrusion should be evaluated as part of future studies. (USGS)

  17. ICEPO: the ion channel electrophysiology ontology

    PubMed Central

    Hinard, V.; Britan, A.; Rougier, J.S.; Bairoch, A.; Abriel, H.; Gaudet, P.

    2016-01-01

    Ion channels are transmembrane proteins that selectively allow ions to flow across the plasma membrane and play key roles in diverse biological processes. A multitude of diseases, called channelopathies, such as epilepsies, muscle paralysis, pain syndromes, cardiac arrhythmias or hypoglycemia are due to ion channel mutations. A wide corpus of literature is available on ion channels, covering both their functions and their roles in disease. The research community needs to access this data in a user-friendly, yet systematic manner. However, extraction and integration of this increasing amount of data have been proven to be difficult because of the lack of a standardized vocabulary that describes the properties of ion channels at the molecular level. To address this, we have developed Ion Channel ElectroPhysiology Ontology (ICEPO), an ontology that allows one to annotate the electrophysiological parameters of the voltage-gated class of ion channels. This ontology is based on a three-state model of ion channel gating describing the three conformations/states that an ion channel can adopt: closed, open and inactivated. This ontology supports the capture of voltage-gated ion channel electrophysiological data from the literature in a structured manner and thus enables other applications such as querying and reasoning tools. Here, we present ICEPO (ICEPO ftp site: ftp://ftp.nextprot.org/pub/current_release/controlled_vocabularies/), as well as examples of its use. PMID:27055825

  18. ICEPO: the ion channel electrophysiology ontology.

    PubMed

    Hinard, V; Britan, A; Rougier, J S; Bairoch, A; Abriel, H; Gaudet, P

    2016-01-01

    Ion channels are transmembrane proteins that selectively allow ions to flow across the plasma membrane and play key roles in diverse biological processes. A multitude of diseases, called channelopathies, such as epilepsies, muscle paralysis, pain syndromes, cardiac arrhythmias or hypoglycemia are due to ion channel mutations. A wide corpus of literature is available on ion channels, covering both their functions and their roles in disease. The research community needs to access this data in a user-friendly, yet systematic manner. However, extraction and integration of this increasing amount of data have been proven to be difficult because of the lack of a standardized vocabulary that describes the properties of ion channels at the molecular level. To address this, we have developed Ion Channel ElectroPhysiology Ontology (ICEPO), an ontology that allows one to annotate the electrophysiological parameters of the voltage-gated class of ion channels. This ontology is based on a three-state model of ion channel gating describing the three conformations/states that an ion channel can adopt: closed, open and inactivated. This ontology supports the capture of voltage-gated ion channel electrophysiological data from the literature in a structured manner and thus enables other applications such as querying and reasoning tools. Here, we present ICEPO (ICEPO ftp site:ftp://ftp.nextprot.org/pub/current_release/controlled_vocabularies/), as well as examples of its use. PMID:27055825

  19. Tavern patrons and the MacAndrew Alcoholism Scale: self-reported drinking behavior in relation to the MMPI L and K scales.

    PubMed

    Ciancio, C; Saltstone, R; Fraboni, M

    1990-09-01

    This study investigated the ability of the MacAndrew Alcoholism (MAC) Scale to distinguish between alcoholics and nonalcoholics using self-ratings from patrons of taverns (N = 128); while only about 14% of the variance in the MAC Scale was accounted for by the self-rating (alcoholic/nonalcoholic) scale, the MAC Scale correctly identified 70% of those who reported alcohol use to levels consistent with alcoholic dependency after variance in the alcohol use scale attributable to the L and K scales of the MMPI was accounted for. PMID:2246380

  20. Management of Symphysis and Parasymphysis Mandibular Fractures in Children Treated with MacLennan Splint: Stability and Early Results

    PubMed Central

    Bhat, Manohar; Sharma, Anupama; Sharma, Rajesh

    2015-01-01

    ABSTRACT Objective: The aim of this study was to assess the safety and efficiency of MacLennan splint in symphysis and parasymphysis mandibular fractures in children. Study design: Six patients (four boys and two girls, mean age 3 years, range between 2 and 5 years) were operated on parasymphysis fractures of children. The mean follow-up time was 12 months. MacLennan splint was applied in these case upto 3 weeks. Results: Primary healing of the fractured mandible was observed in all patients. Postoperative complications were minor and transient. The outcome of the operation was not endangered. Adverse tissue reaction like infection, malocclusion, swelling and growth restrictions did not occur during observation period. Conclusion: MacLennan splint is having various advantages like faster mobilization and the avoidance of secondary removal operations. Based on this preliminary results MacLennan splints are safe and efficient in the treatment of pediatric mandible fracture. How to cite this article: Khairwa A, Bhat M, Sharma A, Sharma R. Management of Symphysis and Parasymphysis Mandibular Fractures in Children Treated with MacLennan Splint: Stability and Early Results. Int J Clin Pediatr Dent 2015;8(2):127-132. PMID:26379381

  1. Application of open-source photogrammetric software MicMac for monitoring surface deformation in laboratory models

    NASA Astrophysics Data System (ADS)

    Galland, Olivier; Bertelsen, Hâvard S.; Guldstrand, Frank; Girod, Luc; Johannessen, Rikke F.; Bjugger, Fanny; Burchardt, Steffi; Mair, Karen

    2016-04-01

    Quantifying deformation is essential in modern laboratory models of geological systems. This paper presents a new laboratory monitoring method through the implementation of the open-source software MicMac, which efficiently implements photogrammetry in Structure-from-Motion algorithms. Critical evaluation is provided using results from two example laboratory geodesy scenarios: magma emplacement and strike-slip faulting. MicMac automatically processes images from synchronized cameras to compute time series of digital elevation models (DEMs) and orthorectified images of model surfaces. MicMac also implements digital image correlation to produce high-resolution displacements maps. The resolution of DEMs and displacement maps corresponds to the pixel size of the processed images. Using 24 MP cameras, the precision of DEMs and displacements is ~0.05 mm on a 40 × 40 cm surface. Processing displacement maps with Matlab® scripts allows automatic fracture mapping on the monitored surfaces. MicMac also offers the possibility to integrate 3-D models of excavated structures with the corresponding surface deformation data. The high resolution and high precision of MicMac results and the ability to generate virtual 3-D models of complex structures make it a very promising tool for quantitative monitoring in laboratory models of geological systems.

  2. Evolutionarily conserved intracellular gate of voltage-dependent sodium channels

    NASA Astrophysics Data System (ADS)

    Oelstrom, Kevin; Goldschen-Ohm, Marcel P.; Holmgren, Miguel; Chanda, Baron

    2014-03-01

    Members of the voltage-gated ion channel superfamily (VGIC) regulate ion flux and generate electrical signals in excitable cells by opening and closing pore gates. The location of the gate in voltage-gated sodium channels, a founding member of this superfamily, remains unresolved. Here we explore the chemical modification rates of introduced cysteines along the S6 helix of domain IV in an inactivation-removed background. We find that state-dependent accessibility is demarcated by an S6 hydrophobic residue; substituted cysteines above this site are not modified by charged thiol reagents when the channel is closed. These accessibilities are consistent with those inferred from open- and closed-state structures of prokaryotic sodium channels. Our findings suggest that an intracellular gate composed of a ring of hydrophobic residues is not only responsible for regulating access to the pore of sodium channels, but is also a conserved feature within canonical members of the VGIC superfamily.

  3. 47 CFR 76.971 - Commercial leased access terms and conditions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... access terms and conditions. (a)(1) Cable operators shall place leased access programmers that request... select from among leased access programmers using objective, content-neutral criteria. (4) Cable... a channel already carrying an existing full-time non-leased access programmer, the operator does...

  4. 47 CFR 76.971 - Commercial leased access terms and conditions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... access terms and conditions. (a)(1) Cable operators shall place leased access programmers that request... select from among leased access programmers using objective, content-neutral criteria. (4) Cable... a channel already carrying an existing full-time non-leased access programmer, the operator does...

  5. 47 CFR 76.971 - Commercial leased access terms and conditions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... access terms and conditions. (a)(1) Cable operators shall place leased access programmers that request... select from among leased access programmers using objective, content-neutral criteria. (4) Cable... a channel already carrying an existing full-time non-leased access programmer, the operator does...

  6. Performance analysis of replication ALOHA for fading mobile communications channels

    NASA Technical Reports Server (NTRS)

    Yan, Tsun-Yee; Clare, Loren P.

    1986-01-01

    This paper describes an ALOHA random access protocol for fading communications channels. A two-state Markov model is used for the channel error process to account for the channel fading memory. The ALOHA protocol is modified to send multiple contiguous copies of a message at each transmission attempt. Both pure and slotted ALOHA channels are considered. The analysis is applicable to fading environments where the channel memory is short compared to the propagation delay. It is shown that smaller delay may be achieved using replications and, in noisy conditions, can also improve throughput.

  7. Time accurate application of the MacCormack 2-4 scheme on massively parallel computers

    NASA Technical Reports Server (NTRS)

    Hudson, Dale A.; Long, Lyle N.

    1995-01-01

    Many recent computational efforts in turbulence and acoustics research have used higher order numerical algorithms. One popular method has been the explicit MacCormack 2-4 scheme. The MacCormack 2-4 scheme is second order accurate in time and fourth order accurate in space, and is stable for CFL's below 2/3. Current research has shown that the method can give accurate results but does exhibit significant Gibbs phenomena at sharp discontinuities. The impact of adding Jameson type second, third, and fourth order artificial viscosity was examined here. Category 2 problems, the nonlinear traveling wave and the Riemann problem, were computed using a CFL number of 0.25. This research has found that dispersion errors can be significantly reduced or nearly eliminated by using a combination of second and third order terms in the damping. Use of second and fourth order terms reduced the magnitude of dispersion errors but not as effectively as the second and third order combination. The program was coded using Thinking Machine's CM Fortran, a variant of Fortran 90/High Performance Fortran, and was executed on a 2K CM-200. Simple extrapolation boundary conditions were used for both problems.

  8. MAC88105 - A regolith breccia from the lunar highlands: Mineralogical, petrological, and geochemical studies

    SciTech Connect

    Koeberl, C. ); Kurat, G.; Branstaetter, F. )

    1991-11-01

    The new large lunar meteorite MAC88105 is a dense breccia, with lithic and mineral clasts and fragments set into a welded matrix. It is a regolith breccia which shows some recrystallization and evidence for a late shock event during which anorthositic glass veins were formed. Shock effects (most probably due to impact ejection from the moon) are present throughout the sample and require a shock pressure of about 25-30 GPa, in agreement with observations made on other lunar meteorites. The presence of devitrified glass (spheres and shards) supports a regolith origin. Most common are meta-meltbreccias consisting of abundant anorthitic plagioclase clasts and a dense, fine-grained matrix. Some fine-grained hornfelsic to granulitic metabreccias are also present. Lithic clast compositions are predominantly anorthositic noritic (or noritic anorthositic), and anorthositic troctolitic. The bulk comparison of MAC88105 is different from that of the lunar meteorites and suggests a different source, which is supported by cosmic-ray and noble gas data. At this time it seems likely that about four individual impact events have been responsible for delivering the seven highland meteorites.

  9. An Energy-Efficient MAC Protocol for Medical Emergency Monitoring Body Sensor Networks

    PubMed Central

    Zhang, Chongqing; Wang, Yinglong; Liang, Yongquan; Shu, Minglei; Chen, Changfang

    2016-01-01

    Medical emergency monitoring body sensor networks (BSNs) monitor the occurrence of medical emergencies and are helpful for the daily care of the elderly and chronically ill people. Such BSNs are characterized by rare traffic when there is no emergency occurring, high real-time and reliable requirements of emergency data and demand for a fast wake-up mechanism for waking up all nodes when an emergency happens. A beacon-enabled MAC protocol is specially designed to meet the demands of medical emergency monitoring BSNs. The rarity of traffic is exploited to improve energy efficiency. By adopting a long superframe structure to avoid unnecessary beacons and allocating most of the superframe to be inactive periods, the duty cycle is reduced to an extremely low level to save energy. Short active time slots are interposed into the superframe and shared by all of the nodes to deliver the emergency data in a low-delay and reliable way to meet the real-time and reliable requirements. The interposition slots can also be used by the coordinator to broadcast network demands to wake-up all nodes in a low-delay and energy-efficient way. Experiments display that the proposed MAC protocol works well in BSNs with low emergency data traffic. PMID:26999145

  10. Design and characterization of specMACS, a multipurpose hyperspectral cloud and sky imager

    NASA Astrophysics Data System (ADS)

    Ewald, Florian; Kölling, Tobias; Baumgartner, Andreas; Zinner, Tobias; Mayer, Bernhard

    2016-05-01

    The new spectrometer of the Munich Aerosol Cloud Scanner (specMACS) is a multipurpose hyperspectral cloud and sky imager designated, but is not limited to investigations of cloud-aerosol interactions in Earth's atmosphere. With its high spectral and spatial resolution, the instrument is designed to measure solar radiation in the visible and shortwave infrared region that is reflected from, or transmitted through clouds and aerosol layers. It is based on two hyperspectral cameras that measure in the solar spectral range between 400 and 2500 nm with a spectral bandwidth between 2.5 and 12.0 nm. The instrument was operated in ground-based campaigns as well as aboard the German High Altitude LOng Range (HALO) research aircraft, e.g., during the ACRIDICON-CHUVA campaign in Brazil during summer 2014. This paper describes the specMACS instrument hardware and software design and characterizes the instrument performance. During the laboratory characterization of the instrument, the radiometric response as well as the spatial and spectral resolution was assessed. Since the instrument is primarily intended for retrievals of atmospheric quantities by inversion of radiative models using measured radiances, a focus is placed on the determination of its radiometric response. Radiometric characterization was possible for both spectrometers, with an absolute accuracy of 3 % at their respective central wavelength regions. First measurements are presented which demonstrate the wide applicability of the instrument. They show that key demands are met regarding the radiometric and spectral accuracy which is required for the intended remote sensing techniques.

  11. Whose disorder?: a constructive MacIntyrean critique of psychiatric nosology.

    PubMed

    Kinghorn, Warren A

    2011-04-01

    The American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM) has for decades been a locus of dispute between ardent defenders of its scientific validity and vociferous critics who charge that it covertly cloaks disputed moral and political judgments in scientific language. This essay explores Alasdair MacIntyre's tripartite typology of moral reasoning--"encyclopedia," "genealogy," and "tradition"--as an analytic lens for appreciation and critique of these debates. The DSM opens itself to corrosive neo-Nietzschean "genealogical" critique, such an analysis holds, only insofar as it is interpreted as a presumptively objective and context-independent encyclopedia free of the contingencies of its originating communities. A MacIntyrean tradition-constituted understanding of the DSM, on the other hand, helpfully allows psychiatric nosology to be understood both as "scientific" and, simultaneously, as inextricable from the political and moral interests--and therefore the moral successes and moral failures--of the psychiatric guild from which it arises. PMID:21357652

  12. Design and Performance Evaluation of a Distributed OFDMA-Based MAC Protocol for MANETs

    PubMed Central

    Chung, Jiyoung; Lee, Hyungyu; Lee, Jung-Ryun

    2014-01-01

    In this paper, we propose a distributed MAC protocol for OFDMA-based wireless mobile ad hoc multihop networks, in which the resource reservation and data transmission procedures are operated in a distributed manner. A frame format is designed considering the characteristics of OFDMA that each node can transmit or receive data to or from multiple nodes simultaneously. Under this frame structure, we propose a distributed resource management method including network state estimation and resource reservation processes. We categorize five types of logical errors according to their root causes and show that two of the logical errors are inevitable while three of them are avoided under the proposed distributed MAC protocol. In addition, we provide a systematic method to determine the advertisement period of each node by presenting a clear relation between the accuracy of estimated network states and the signaling overhead. We evaluate the performance of the proposed protocol in respect of the reservation success rate and the success rate of data transmission. Since our method focuses on avoiding logical errors, it could be easily placed on top of the other resource allocation methods focusing on the physical layer issues of the resource management problem and interworked with them. PMID:25133254

  13. MAC versus PC: Determinism and randomness as complementary approaches to robotic exploration of continuous unknown domains

    SciTech Connect

    Wagner, I.A.; Lindenbaum, M.; Bruckstein, A.M.

    2000-01-01

    Three methods are described for exploring a continuous unknown planar region by a group of robots having limited sensors and no explicit communication. The authors formalize the problem, prove that its off-line version is NP-hard, and show a lower bound on the length of any solution. Then a deterministic mark and cover (MAC) algorithm is described for the on-line problem using short-lived navigational markers as a means of navigation and indirect communication. The convergence of the algorithm is proved, and its cover time is shown to be the asymptotically optimal O(A/a), where A is the total area and a is the area covered by the robot in a single step. The MAC algorithm is tested against an alternative randomized probabilistic covering (PC) method, which does not rely on sensors but is still able to cover an unknown region in an expected time that depends polynomially on the dimensions of the region. Both algorithms enable cooperation of several robots to achieve faster coverage. Finally, they show that the two methods can be combined to yield a third, hybrid algorithm with a better trade-off between performance and robustness.

  14. The rise of empirical research in medical ethics: a MacIntyrean critique and proposal.

    PubMed

    Lawrence, Ryan E; Curlin, Farr A

    2011-04-01

    Hume's is/ought distinction has long limited the role of empirical research in ethics, saying that data about what something is cannot yield conclusions about the way things ought to be. However, interest in empirical research in ethics has been growing despite this countervailing principle. We attribute some of this increased interest to a conceptual breakdown of the is/ought distinction. MacIntyre, in reviewing the history of the is/ought distinction, argues that is and ought are not strictly separate realms but exist in a close relationship that is clarified by adopting a teleological orientation. We propose that, instead of recovering a teleological orientation, society tends to generate its own goals via democratic methods like those described by Rousseau or adopt agnosticism about teleology such as described by Richard Rorty. In both latter scenarios, the distinction between is and ought is obscured, and the role for empirical research grows, but for controversial reasons. MacIntyre warns that the is/ought distinction should remain, but reminds ethicists to make careful arguments about when and why it is legitimate to move from is to ought. PMID:21339390

  15. An Energy-Efficient MAC Protocol for Medical Emergency Monitoring Body Sensor Networks.

    PubMed

    Zhang, Chongqing; Wang, Yinglong; Liang, Yongquan; Shu, Minglei; Chen, Changfang

    2016-01-01

    Medical emergency monitoring body sensor networks (BSNs) monitor the occurrence of medical emergencies and are helpful for the daily care of the elderly and chronically ill people. Such BSNs are characterized by rare traffic when there is no emergency occurring, high real-time and reliable requirements of emergency data and demand for a fast wake-up mechanism for waking up all nodes when an emergency happens. A beacon-enabled MAC protocol is specially designed to meet the demands of medical emergency monitoring BSNs. The rarity of traffic is exploited to improve energy efficiency. By adopting a long superframe structure to avoid unnecessary beacons and allocating most of the superframe to be inactive periods, the duty cycle is reduced to an extremely low level to save energy. Short active time slots are interposed into the superframe and shared by all of the nodes to deliver the emergency data in a low-delay and reliable way to meet the real-time and reliable requirements. The interposition slots can also be used by the coordinator to broadcast network demands to wake-up all nodes in a low-delay and energy-efficient way. Experiments display that the proposed MAC protocol works well in BSNs with low emergency data traffic. PMID:26999145

  16. Convergence Analysis of Triangular MAC Schemes for Two Dimensional Stokes Equations

    PubMed Central

    Wang, Ming; Zhong, Lin

    2015-01-01

    In this paper, we consider the use of H(div) elements in the velocity–pressure formulation to discretize Stokes equations in two dimensions. We address the error estimate of the element pair RT0–P0, which is known to be suboptimal, and render the error estimate optimal by the symmetry of the grids and by the superconvergence result of Lagrange inter-polant. By enlarging RT0 such that it becomes a modified BDM-type element, we develop a new discretization BDM1b–P0. We, therefore, generalize the classical MAC scheme on rectangular grids to triangular grids and retain all the desirable properties of the MAC scheme: exact divergence-free, solver-friendly, and local conservation of physical quantities. Further, we prove that the proposed discretization BDM1b–P0 achieves the optimal convergence rate for both velocity and pressure on general quasi-uniform grids, and one and half order convergence rate for the vorticity and a recovered pressure. We demonstrate the validity of theories developed here by numerical experiments. PMID:26041948

  17. Islands as model systems in ecology and evolution: prospects fifty years after MacArthur-Wilson.

    PubMed

    Warren, Ben H; Simberloff, Daniel; Ricklefs, Robert E; Aguilée, Robin; Condamine, Fabien L; Gravel, Dominique; Morlon, Hélène; Mouquet, Nicolas; Rosindell, James; Casquet, Juliane; Conti, Elena; Cornuault, Josselin; Fernández-Palacios, José María; Hengl, Tomislav; Norder, Sietze J; Rijsdijk, Kenneth F; Sanmartín, Isabel; Strasberg, Dominique; Triantis, Kostas A; Valente, Luis M; Whittaker, Robert J; Gillespie, Rosemary G; Emerson, Brent C; Thébaud, Christophe

    2015-02-01

    The study of islands as model systems has played an important role in the development of evolutionary and ecological theory. The 50th anniversary of MacArthur and Wilson's (December 1963) article, 'An equilibrium theory of insular zoogeography', was a recent milestone for this theme. Since 1963, island systems have provided new insights into the formation of ecological communities. Here, building on such developments, we highlight prospects for research on islands to improve our understanding of the ecology and evolution of communities in general. Throughout, we emphasise how attributes of islands combine to provide unusual research opportunities, the implications of which stretch far beyond islands. Molecular tools and increasing data acquisition now permit re-assessment of some fundamental issues that interested MacArthur and Wilson. These include the formation of ecological networks, species abundance distributions, and the contribution of evolution to community assembly. We also extend our prospects to other fields of ecology and evolution - understanding ecosystem functioning, speciation and diversification - frequently employing assets of oceanic islands in inferring the geographic area within which evolution has occurred, and potential barriers to gene flow. Although island-based theory is continually being enriched, incorporating non-equilibrium dynamics is identified as a major challenge for the future. PMID:25560682

  18. Facile Synthesis of DendriMac Polymers via the Combination of Living Anionic Polymerization and Highly Efficient Coupling Reactions.

    PubMed

    Ma, Hongwei; Wang, Qiuyun; Sang, Wei; Han, Li; Liu, Pibo; Sheng, Heyu; Wang, Yurong; Li, Yang

    2016-01-01

    Two DendriMac polymers (Dendri-hydr and Dendri-click) are efficiently and conveniently synthesized via the combination of living anionic polymerization (LAP) and hydrosilylation/click chemistry. Based on the end-capping of DPE derivatives (DPE-SiH and DPE-DA) toward polymeric anions, the polymeric core and arms are effectively synthesized, and the base polymers can be regarded as polymeric bricks. Hydrosilylation and click chemistry are used as coupling reactions to construct the DendriMac polymers with high efficiency and convenience. The numbers of branched arms are calculated by SEC as 5.84 and 6.08 for Dendri-hydr and Dendri-click, respectively, which indicate that the DendriMac architectures exhibit high structural integrity. Because of its independence, high efficiency, and convenience, the whole construction can be regarded as the "building of polymeric bricks." PMID:26501193

  19. The Discovery Channel Telescope

    NASA Astrophysics Data System (ADS)

    Millis, R. L.; Dunham, E. W.; Sebring, T. A.; Smith, B. W.; de Kock, M.; Wiecha, O.

    2004-11-01

    The Discovery Channel Telescope (DCT) is a 4.2-m telescope to be built at a new site near Happy Jack, Arizona. The DCT features a large prime focus mosaic CCD camera with a 2-degree-diameter field of view especially designed for surveys of KBOs, Centaurs, NEAs and other moving or time-variable targets. The telescope can be switched quickly to a Ritchey-Chretien configuration for optical/IR spectroscopy or near-IR imaging. This flexibility allows timely follow-up physical studies of high priority objects discovered in survey mode. The ULE (ultra-low-expansion) meniscus primary and secondary mirror blanks for the telescope are currently in fabrication by Corning Glass. Goodrich Aerospace, Vertex RSI, M3 Engineering and Technology Corp., and e2v Technologies have recently completed in-depth conceptual design studies of the optics, mount, enclosure, and mosaic focal plane, respectively. The results of these studies were subjected to a formal design review in July, 2004. Site testing at the 7760-ft altitude Happy Jack site began in 2001. Differential image motion observations from 117 nights since January 1, 2003 gave median seeing of 0.84 arcsec FWHM, and the average of the first quartile was 0.62 arcsec. The National Environmental Policy Act (NEPA) process for securing long-term access to this site on the Coconino National Forest is nearing completion and ground breaking is expected in the spring of 2005. The Discovery Channel Telescope is a project of the Lowell Observatory with major financial support from Discovery Communications, Inc. (DCI). DCI plans ongoing television programming featuring the construction of the telescope and the research ultimately undertaken with the DCT. An additional partner can be accommodated in the project. Interested parties should contact the lead author.

  20. The MacNew Questionnaire Is a Helpful Tool for Predicting Unplanned Hospital Readmissions After Coronary Revascularization

    PubMed Central

    Baldi, Cesare; De Vecchis, Renato; Ariano, Carmelina

    2016-01-01

    Background The MacNew questionnaire is a neuro-behavioral tool which is easy and immediately usable. This self-reported questionnaire filled out by the patient allows the physician to achieve helpful information concerning the ways for optimizing the therapy and patient’s lifestyles. In this retrospective study, our aim was to assess whether relatively high scores found using the MacNew questionnaire in patients who had undergone percutaneous or surgical revascularization were associated with a decreased risk of unscheduled hospitalizations during the follow-up. Methods A retrospective analysis concerning 210 patients was carried out. The clinical sheets of these patients were examined as regards the information provided in the specific questionnaires (MacNew Italian version) routinely administered during the hospitalization prescribed for recovering from recent interventions of coronary percutaneous or surgery revascularization. Every patient undergoing the psychological test with MacNew questionnaire was followed up for 3 years. Results Using univariate analysis, a global score’s high value (i.e., above the median of the whole examined population) was shown to be associated with a significantly decreased risk of rehospitalization (HR (hazard ratio): 0.4312; 95% CI: 0.3463 - 0.5370; P < 0.0001). After adjustment for age, gender and myocardial infarction as initiating event, using a multivariate Cox proportional hazards regression model, the protection exerted by a high MacNew score against the risk of hospitalizations remained significant (HR: 0.0885; 95% CI: 0.0317 - 0.2472; P < 0.0001). Conclusions A relatively elevated MacNew global score appears to be associated with a significantly decreased risk of unscheduled hospitalizations after coronary revascularization over a 3-year follow-up. PMID:26858793