Searchable attribute-based encryption scheme with attribute revocation in cloud storage.

PubMed

Wang, Shangping; Zhao, Duqiao; Zhang, Yaling

2017-01-01

Attribute based encryption (ABE) is a good way to achieve flexible and secure access control to data, and attribute revocation is the extension of the attribute-based encryption, and the keyword search is an indispensable part for cloud storage. The combination of both has an important application in the cloud storage. In this paper, we construct a searchable attribute-based encryption scheme with attribute revocation in cloud storage, the keyword search in our scheme is attribute based with access control, when the search succeeds, the cloud server returns the corresponding cipher text to user and the user can decrypt the cipher text definitely. Besides, our scheme supports multiple keywords search, which makes the scheme more practical. Under the assumption of decisional bilinear Diffie-Hellman exponent (q-BDHE) and decisional Diffie-Hellman (DDH) in the selective security model, we prove that our scheme is secure.

Energy-Efficient Implementation of ECDH Key Exchange for Wireless Sensor Networks

NASA Astrophysics Data System (ADS)

Lederer, Christian; Mader, Roland; Koschuch, Manuel; Großschädl, Johann; Szekely, Alexander; Tillich, Stefan

Wireless Sensor Networks (WSNs) are playing a vital role in an ever-growing number of applications ranging from environmental surveillance over medical monitoring to home automation. Since WSNs are often deployed in unattended or even hostile environments, they can be subject to various malicious attacks, including the manipulation and capture of nodes. The establishment of a shared secret key between two or more individual nodes is one of the most important security services needed to guarantee the proper functioning of a sensor network. Despite some recent advances in this field, the efficient implementation of cryptographic key establishment for WSNs remains a challenge due to the resource constraints of small sensor nodes such as the MICAz mote. In this paper we present a lightweight implementation of the elliptic curve Diffie-Hellman (ECDH) key exchange for ZigBee-compliant sensor nodes equipped with an ATmega128 processor running the TinyOS operating system. Our implementation uses a 192-bit prime field specified by the NIST as underlying algebraic structure and requires only 5.20 ·106 clock cycles to compute a scalar multiplication if the base point is fixed and known a priori. A scalar multiplication using a random base point takes about 12.33 ·106 cycles. Our results show that a full ECDH key exchange between two MICAz motes consumes an energy of 57.33 mJ (including radio communication), which is significantly better than most previously reported ECDH implementations on comparable platforms.

Secure SCADA communication by using a modified key management scheme.

PubMed

Rezai, Abdalhossein; Keshavarzi, Parviz; Moravej, Zahra

2013-07-01

This paper presents and evaluates a new cryptographic key management scheme which increases the efficiency and security of the Supervisory Control And Data Acquisition (SCADA) communication. In the proposed key management scheme, two key update phases are used: session key update and master key update. In the session key update phase, session keys are generated in the master station. In the master key update phase, the Elliptic Curve Diffie-Hellman (ECDH) protocol is used. The Poisson process is also used to model the Security Index (SI) and Quality of Service (QoS). Our analysis shows that the proposed key management not only supports the required speed in the MODBUS implementation but also has several advantages compared to other key management schemes for secure communication in SCADA networks. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

A Round-Efficient Authenticated Key Agreement Scheme Based on Extended Chaotic Maps for Group Cloud Meeting.

PubMed

Lin, Tsung-Hung; Tsung, Chen-Kun; Lee, Tian-Fu; Wang, Zeng-Bo

2017-12-03

The security is a critical issue for business purposes. For example, the cloud meeting must consider strong security to maintain the communication privacy. Considering the scenario with cloud meeting, we apply extended chaotic map to present passwordless group authentication key agreement, termed as Passwordless Group Authentication Key Agreement (PL-GAKA). PL-GAKA improves the computation efficiency for the simple group password-based authenticated key agreement (SGPAKE) proposed by Lee et al. in terms of computing the session key. Since the extended chaotic map has equivalent security level to the Diffie-Hellman key exchange scheme applied by SGPAKE, the security of PL-GAKA is not sacrificed when improving the computation efficiency. Moreover, PL-GAKA is a passwordless scheme, so the password maintenance is not necessary. Short-term authentication is considered, hence the communication security is stronger than other protocols by dynamically generating session key in each cloud meeting. In our analysis, we first prove that each meeting member can get the correct information during the meeting. We analyze common security issues for the proposed PL-GAKA in terms of session key security, mutual authentication, perfect forward security, and data integrity. Moreover, we also demonstrate that communicating in PL-GAKA is secure when suffering replay attacks, impersonation attacks, privileged insider attacks, and stolen-verifier attacks. Eventually, an overall comparison is given to show the performance between PL-GAKA, SGPAKE and related solutions.

FRR: fair remote retrieval of outsourced private medical records in electronic health networks.

PubMed

Wang, Huaqun; Wu, Qianhong; Qin, Bo; Domingo-Ferrer, Josep

2014-08-01

Cloud computing is emerging as the next-generation IT architecture. However, cloud computing also raises security and privacy concerns since the users have no physical control over the outsourced data. This paper focuses on fairly retrieving encrypted private medical records outsourced to remote untrusted cloud servers in the case of medical accidents and disputes. Our goal is to enable an independent committee to fairly recover the original private medical records so that medical investigation can be carried out in a convincing way. We achieve this goal with a fair remote retrieval (FRR) model in which either t investigation committee members cooperatively retrieve the original medical data or none of them can get any information on the medical records. We realize the first FRR scheme by exploiting fair multi-member key exchange and homomorphic privately verifiable tags. Based on the standard computational Diffie-Hellman (CDH) assumption, our scheme is provably secure in the random oracle model (ROM). A detailed performance analysis and experimental results show that our scheme is efficient in terms of communication and computation. Copyright © 2014 Elsevier Inc. All rights reserved.

Security Proof for Password Authentication in TLS-Verifier-based Three-Party Group Diffie-Hellman

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chevassut, Olivier; Milner, Joseph; Pointcheval, David

2008-04-21

The internet has grown greatly in the past decade, by some numbers exceeding 47 million active web sites and a total aggregate exceeding100 million web sites. What is common practice today on the Internet is that servers have public keys, but clients are largely authenticated via short passwords. Protecting these passwords by not storing them in the clear on institutions's servers has become a priority. This paper develops password-based ciphersuites for the Transport Layer Security (TLS) protocol that are: (1) resistant to server compromise; (2) provably secure; (3) believed to be free from patent and licensing restrictions based on anmore » analysis of relevant patents in the area.« less

Formal Methods for Cryptographic Protocol Analysis: Emerging Issues and Trends

DTIC Science & Technology

2003-01-01

signatures , which depend upon the homomor- phic properties of RSA. Other algorithms and data structures, such as Chaum mixes [17], designed for...Communications Security, pages 176–185. ACM, Novem- ber 2001. [17] D. Chaum . Untraceable electronic mail, return addresses and digital signatures ...something like the Diffie- Hellman algorithm, which depends, as a minimum, on the commutative properties of exponentiation, or something like Chaum’s blinded

Secure open cloud in data transmission using reference pattern and identity with enhanced remote privacy checking

NASA Astrophysics Data System (ADS)

Vijay Singh, Ran; Agilandeeswari, L.

2017-11-01

To handle the large amount of client’s data in open cloud lots of security issues need to be address. Client’s privacy should not be known to other group members without data owner’s valid permission. Sometime clients are fended to have accessing with open cloud servers due to some restrictions. To overcome the security issues and these restrictions related to storing, data sharing in an inter domain network and privacy checking, we propose a model in this paper which is based on an identity based cryptography in data transmission and intermediate entity which have client’s reference with identity that will take control handling of data transmission in an open cloud environment and an extended remote privacy checking technique which will work at admin side. On behalf of data owner’s authority this proposed model will give best options to have secure cryptography in data transmission and remote privacy checking either as private or public or instructed. The hardness of Computational Diffie-Hellman assumption algorithm for key exchange makes this proposed model more secure than existing models which are being used for public cloud environment.

Secure privacy-preserving biometric authentication scheme for telecare medicine information systems.

PubMed

Li, Xuelei; Wen, Qiaoyan; Li, Wenmin; Zhang, Hua; Jin, Zhengping

2014-11-01

Healthcare delivery services via telecare medicine information systems (TMIS) can help patients to obtain their desired telemedicine services conveniently. However, information security and privacy protection are important issues and crucial challenges in healthcare information systems, where only authorized patients and doctors can employ telecare medicine facilities and access electronic medical records. Therefore, a secure authentication scheme is urgently required to achieve the goals of entity authentication, data confidentiality and privacy protection. This paper investigates a new biometric authentication with key agreement scheme, which focuses on patient privacy and medical data confidentiality in TMIS. The new scheme employs hash function, fuzzy extractor, nonce and authenticated Diffie-Hellman key agreement as primitives. It provides patient privacy protection, e.g., hiding identity from being theft and tracked by unauthorized participant, and preserving password and biometric template from being compromised by trustless servers. Moreover, key agreement supports secure transmission by symmetric encryption to protect patient's medical data from being leaked. Finally, the analysis shows that our proposal provides more security and privacy protection for TMIS.

A Secure Cloud-Assisted Wireless Body Area Network in Mobile Emergency Medical Care System.

PubMed

Li, Chun-Ta; Lee, Cheng-Chi; Weng, Chi-Yao

2016-05-01

Recent advances in medical treatment and emergency applications, the need of integrating wireless body area network (WBAN) with cloud computing can be motivated by providing useful and real time information about patients' health state to the doctors and emergency staffs. WBAN is a set of body sensors carried by the patient to collect and transmit numerous health items to medical clouds via wireless and public communication channels. Therefore, a cloud-assisted WBAN facilitates response in case of emergency which can save patients' lives. Since the patient's data is sensitive and private, it is important to provide strong security and protection on the patient's medical data over public and insecure communication channels. In this paper, we address the challenge of participant authentication in mobile emergency medical care systems for patients supervision and propose a secure cloud-assisted architecture for accessing and monitoring health items collected by WBAN. For ensuring a high level of security and providing a mutual authentication property, chaotic maps based authentication and key agreement mechanisms are designed according to the concept of Diffie-Hellman key exchange, which depends on the CMBDLP and CMBDHP problems. Security and performance analyses show how the proposed system guaranteed the patient privacy and the system confidentiality of sensitive medical data while preserving the low computation property in medical treatment and remote medical monitoring.

Enhanced smartcard-based password-authenticated key agreement using extended chaotic maps.

PubMed

Lee, Tian-Fu; Hsiao, Chia-Hung; Hwang, Shi-Han; Lin, Tsung-Hung

2017-01-01

A smartcard based password-authenticated key agreement scheme enables a legal user to log in to a remote authentication server and access remote services through public networks using a weak password and a smart card. Lin recently presented an improved chaotic maps-based password-authenticated key agreement scheme that used smartcards to eliminate the weaknesses of the scheme of Guo and Chang, which does not provide strong user anonymity and violates session key security. However, the improved scheme of Lin does not exhibit the freshness property and the validity of messages so it still fails to withstand denial-of-service and privileged-insider attacks. Additionally, a single malicious participant can predetermine the session key such that the improved scheme does not exhibit the contributory property of key agreements. This investigation discusses these weaknesses and proposes an enhanced smartcard-based password-authenticated key agreement scheme that utilizes extended chaotic maps. The session security of this enhanced scheme is based on the extended chaotic map-based Diffie-Hellman problem, and is proven in the real-or-random and the sequence of games models. Moreover, the enhanced scheme ensures the freshness of communicating messages by appending timestamps, and thereby avoids the weaknesses in previous schemes.

Enhanced smartcard-based password-authenticated key agreement using extended chaotic maps

PubMed Central

Lee, Tian-Fu; Hsiao, Chia-Hung; Hwang, Shi-Han

2017-01-01

A smartcard based password-authenticated key agreement scheme enables a legal user to log in to a remote authentication server and access remote services through public networks using a weak password and a smart card. Lin recently presented an improved chaotic maps-based password-authenticated key agreement scheme that used smartcards to eliminate the weaknesses of the scheme of Guo and Chang, which does not provide strong user anonymity and violates session key security. However, the improved scheme of Lin does not exhibit the freshness property and the validity of messages so it still fails to withstand denial-of-service and privileged-insider attacks. Additionally, a single malicious participant can predetermine the session key such that the improved scheme does not exhibit the contributory property of key agreements. This investigation discusses these weaknesses and proposes an enhanced smartcard-based password-authenticated key agreement scheme that utilizes extended chaotic maps. The session security of this enhanced scheme is based on the extended chaotic map-based Diffie-Hellman problem, and is proven in the real-or-random and the sequence of games models. Moreover, the enhanced scheme ensures the freshness of communicating messages by appending timestamps, and thereby avoids the weaknesses in previous schemes. PMID:28759615

Using Sphinx to Improve Onion Routing Circuit Construction

NASA Astrophysics Data System (ADS)

Kate, Aniket; Goldberg, Ian

This paper presents compact message formats for onion routing circuit construction using the Sphinx methodology developed for mixes. We significantly compress the circuit construction messages for three onion routing protocols that have emerged as enhancements to the Tor anonymizing network; namely, Tor with predistributed Diffie-Hellman values, pairing-based onion routing, and certificateless onion routing. Our new circuit constructions are also secure in the universal composability framework, a property that was missing from the original constructions. Further, we compare the performance of our schemes with their older counterparts as well as with each other.

Characterizing the Efficacy of the NRL Network Pump in Mitigating Covert Timing Channels

DTIC Science & Technology

2012-02-01

of Diffie-Hellman, RSA, DSS, and other systems,” in Advances in CryptologyCRYPTO96. Springer, 1996, pp. 104–113. [16] D . Chaum , “Blind signatures for...transmits Xi = ei(W ) across the channel. The decoder takes the channel outputs Y n and forms an estimate of the original message Ŵ = d (Y n). To...communicate W reliably, it can be shown that the “essence” of this problem is to design e(·) and subsequently d (·) to maximize the mutual information I(W ;Y n

An Enhanced Privacy-Preserving Authentication Scheme for Vehicle Sensor Networks.

PubMed

Zhou, Yousheng; Zhao, Xiaofeng; Jiang, Yi; Shang, Fengjun; Deng, Shaojiang; Wang, Xiaojun

2017-12-08

Vehicle sensor networks (VSNs) are ushering in a promising future by enabling more intelligent transportation systems and providing a more efficient driving experience. However, because of their inherent openness, VSNs are subject to a large number of potential security threats. Although various authentication schemes have been proposed for addressing security problems, they are not suitable for VSN applications because of their high computation and communication costs. Chuang and Lee have developed a trust-extended authentication mechanism (TEAM) for vehicle-to-vehicle communication using a transitive trust relationship, which they claim can resist various attacks. However, it fails to counter internal attacks because of the utilization of a shared secret key. In this paper, to eliminate the vulnerability of TEAM, an enhanced privacy-preserving authentication scheme for VSNs is constructed. The security of our proposed scheme is proven under the random oracle model based on the assumption of the computational Diffie-Hellman problem.

A Secure Authenticated Key Exchange Protocol for Credential Services

NASA Astrophysics Data System (ADS)

Shin, Seonghan; Kobara, Kazukuni; Imai, Hideki

In this paper, we propose a leakage-resilient and proactive authenticated key exchange (called LRP-AKE) protocol for credential services which provides not only a higher level of security against leakage of stored secrets but also secrecy of private key with respect to the involving server. And we show that the LRP-AKE protocol is provably secure in the random oracle model with the reduction to the computational Difie-Hellman problem. In addition, we discuss about some possible applications of the LRP-AKE protocol.

A Provably-Secure Transmission Scheme for Wireless Body Area Networks.

PubMed

Omala, Anyembe Andrew; Robert, Niyifasha; Li, Fagen

2016-11-01

Wireless body area network (WBANs) is composed of sensors that collect and transmit a person's physiological data to health-care providers in real-time. In order to guarantee security of this data over open networks, a secure data transmission mechanism between WBAN and application provider's servers is of necessity. Modified medical data does not provide a true reflection of an individuals state of health and its subsequent use for diagnosis could lead to an irreversible medical condition. In this paper, we propose a lightweight certificateless signcryption scheme for secure transmission of data between WBAN and servers. Our proposed scheme not only provides confidentiality of data and authentication in a single logical step, it is lightweight and resistant to key escrow attacks. We further provide security proof that our scheme provides indistinguishability against adaptive chosen ciphertext attack and unforgeability against adaptive chosen message attack in random oracle model. Compared with two other Diffie-Hellman based signcryption schemes proposed by Barbosa and Farshim (BF) and another by Yin and Liang (YL), our scheme consumes 46 % and 8 % less energy during signcryption than BF and YL scheme respectively.

A Secured Authentication Protocol for SIP Using Elliptic Curves Cryptography

NASA Astrophysics Data System (ADS)

Chen, Tien-Ho; Yeh, Hsiu-Lien; Liu, Pin-Chuan; Hsiang, Han-Chen; Shih, Wei-Kuan

Session initiation protocol (SIP) is a technology regularly performed in Internet Telephony, and Hyper Text Transport Protocol (HTTP) as digest authentication is one of the major methods for SIP authentication mechanism. In 2005, Yang et al. pointed out that HTTP could not resist server spoofing attack and off-line guessing attack and proposed a secret authentication with Diffie-Hellman concept. In 2009, Tsai proposed a nonce based authentication protocol for SIP. In this paper, we demonstrate that their protocol could not resist the password guessing attack and insider attack. Furthermore, we propose an ECC-based authentication mechanism to solve their issues and present security analysis of our protocol to show that ours is suitable for applications with higher security requirement.

Cryptographic framework for document-objects resulting from multiparty collaborative transactions.

PubMed

Goh, A

2000-01-01

Multiparty transactional frameworks--i.e. Electronic Data Interchange (EDI) or Health Level (HL) 7--often result in composite documents which can be accurately modelled using hyperlinked document-objects. The structural complexity arising from multiauthor involvement and transaction-specific sequencing would be poorly handled by conventional digital signature schemes based on a single evaluation of a one-way hash function and asymmetric cryptography. In this paper we outline the generation of structure-specific authentication hash-trees for the the authentication of transactional document-objects, followed by asymmetric signature generation on the hash-tree value. Server-side multi-client signature verification would probably constitute the single most compute-intensive task, hence the motivation for our usage of the Rabin signature protocol which results in significantly reduced verification workloads compared to the more commonly applied Rivest-Shamir-Adleman (RSA) protocol. Data privacy is handled via symmetric encryption of message traffic using session-specific keys obtained through key-negotiation mechanisms based on discrete-logarithm cryptography. Individual client-to-server channels can be secured using a double key-pair variation of Diffie-Hellman (DH) key negotiation, usage of which also enables bidirectional node authentication. The reciprocal server-to-client multicast channel is secured through Burmester-Desmedt (BD) key-negotiation which enjoys significant advantages over the usual multiparty extensions to the DH protocol. The implementation of hash-tree signatures and bi/multidirectional key negotiation results in a comprehensive cryptographic framework for multiparty document-objects satisfying both authentication and data privacy requirements.

A keyword searchable attribute-based encryption scheme with attribute update for cloud storage.

PubMed

Wang, Shangping; Ye, Jian; Zhang, Yaling

2018-01-01

Ciphertext-policy attribute-based encryption (CP-ABE) scheme is a new type of data encryption primitive, which is very suitable for data cloud storage for its fine-grained access control. Keyword-based searchable encryption scheme enables users to quickly find interesting data stored in the cloud server without revealing any information of the searched keywords. In this work, we provide a keyword searchable attribute-based encryption scheme with attribute update for cloud storage, which is a combination of attribute-based encryption scheme and keyword searchable encryption scheme. The new scheme supports the user's attribute update, especially in our new scheme when a user's attribute need to be updated, only the user's secret key related with the attribute need to be updated, while other user's secret key and the ciphertexts related with this attribute need not to be updated with the help of the cloud server. In addition, we outsource the operation with high computation cost to cloud server to reduce the user's computational burden. Moreover, our scheme is proven to be semantic security against chosen ciphertext-policy and chosen plaintext attack in the general bilinear group model. And our scheme is also proven to be semantic security against chosen keyword attack under bilinear Diffie-Hellman (BDH) assumption.

A keyword searchable attribute-based encryption scheme with attribute update for cloud storage

PubMed Central

Wang, Shangping; Zhang, Yaling

2018-01-01

Ciphertext-policy attribute-based encryption (CP-ABE) scheme is a new type of data encryption primitive, which is very suitable for data cloud storage for its fine-grained access control. Keyword-based searchable encryption scheme enables users to quickly find interesting data stored in the cloud server without revealing any information of the searched keywords. In this work, we provide a keyword searchable attribute-based encryption scheme with attribute update for cloud storage, which is a combination of attribute-based encryption scheme and keyword searchable encryption scheme. The new scheme supports the user's attribute update, especially in our new scheme when a user's attribute need to be updated, only the user's secret key related with the attribute need to be updated, while other user's secret key and the ciphertexts related with this attribute need not to be updated with the help of the cloud server. In addition, we outsource the operation with high computation cost to cloud server to reduce the user's computational burden. Moreover, our scheme is proven to be semantic security against chosen ciphertext-policy and chosen plaintext attack in the general bilinear group model. And our scheme is also proven to be semantic security against chosen keyword attack under bilinear Diffie-Hellman (BDH) assumption. PMID:29795577

Quantum cryptography: a view from classical cryptography

NASA Astrophysics Data System (ADS)

Buchmann, Johannes; Braun, Johannes; Demirel, Denise; Geihs, Matthias

2017-06-01

Much of digital data requires long-term protection of confidentiality, for example, medical health records. Cryptography provides such protection. However, currently used cryptographic techniques such as Diffe-Hellman key exchange may not provide long-term security. Such techniques rely on certain computational assumptions, such as the hardness of the discrete logarithm problem that may turn out to be incorrect. On the other hand, quantum cryptography---in particular quantum random number generation and quantum key distribution---offers information theoretic protection. In this paper, we explore the challenge of providing long-term confidentiality and we argue that a combination of quantum cryptography and classical cryptography can provide such protection.

Extending the IEEE 802.15.4 Security Suite with a Compact Implementation of the NIST P-192/B-163 Elliptic Curves

PubMed Central

de la Piedra, Antonio; Braeken, An; Touhafi, Abdellah

2013-01-01

Typically, commercial sensor nodes are equipped with MCUsclocked at a low-frequency (i.e., within the 4–12 MHz range). Consequently, executing cryptographic algorithms in those MCUs generally requires a huge amount of time. In this respect, the required energy consumption can be higher than using a separate accelerator based on a Field-programmable Gate Array (FPGA) that is switched on when needed. In this manuscript, we present the design of a cryptographic accelerator suitable for an FPGA-based sensor node and compliant with the IEEE802.15.4 standard. All the embedded resources of the target platform (Xilinx Artix-7) have been maximized in order to provide a cost-effective solution. Moreover, we have added key negotiation capabilities to the IEEE 802.15.4 security suite based on Elliptic Curve Cryptography (ECC;. Our results suggest that tailored accelerators based on FPGA can behave better in terms of energy than contemporary software solutions for motes, such as the TinyECC and NanoECC libraries. In this regard, a point multiplication (PM) can be performed between 8.58- and 15.4-times faster, 3.40- to 23.59-times faster (Elliptic Curve Diffie-Hellman, ECDH) and between 5.45- and 34.26-times faster (Elliptic Curve Integrated Encryption Scheme, ECIES). Moreover, the energy consumption was also improved with a factor of 8.96 (PM). PMID:23899936

Extending the IEEE 802.15.4 security suite with a compact implementation of the NIST P-192/B-163 elliptic curves.

PubMed

de la Piedra, Antonio; Braeken, An; Touhafi, Abdellah

2013-07-29

Typically, commercial sensor nodes are equipped with MCUsclocked at a low-frequency (i.e., within the 4-12 MHz range). Consequently, executing cryptographic algorithms in those MCUs generally requires a huge amount of time. In this respect, the required energy consumption can be higher than using a separate accelerator based on a Field-programmable Gate Array (FPGA) that is switched on when needed. In this manuscript, we present the design of a cryptographic accelerator suitable for an FPGA-based sensor node and compliant with the IEEE802.15.4 standard. All the embedded resources of the target platform (Xilinx Artix-7) have been maximized in order to provide a cost-effective solution. Moreover, we have added key negotiation capabilities to the IEEE 802.15.4 security suite based on Elliptic Curve Cryptography (ECC). Our results suggest that tailored accelerators based on FPGA can behave better in terms of energy than contemporary software solutions for motes, such as the TinyECC and NanoECC libraries. In this regard, a point multiplication (PM) can be performed between 8.58- and 15.4-times faster, 3.40- to 23.59-times faster (Elliptic Curve Diffie-Hellman, ECDH) and between 5.45- and 34.26-times faster (Elliptic Curve Integrated Encryption Scheme, ECIES). Moreover, the energy consumption was also improved with a factor of 8.96 (PM).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strait, R.S.; Pearson, P.K.; Sengupta, S.K.

A password system comprises a set of codewords spaced apart from one another by a Hamming distance (HD) that exceeds twice the variability that can be projected for a series of biometric measurements for a particular individual and that is less than the HD that can be encountered between two individuals. To enroll an individual, a biometric measurement is taken and exclusive-ORed with a random codeword to produce a reference value. To verify the individual later, a biometric measurement is taken and exclusive-ORed with the reference value to reproduce the original random codeword or its approximation. If the reproduced valuemore » is not a codeword, the nearest codeword to it is found, and the bits that were corrected to produce the codeword to it is found, and the bits that were corrected to produce the codeword are also toggled in the biometric measurement taken and the codeword generated during enrollment. The correction scheme can be implemented by any conventional error correction code such as Reed-Muller code R(m,n). In the implementation using a hand geometry device an R(2,5) code has been used in this invention. Such codeword and biometric measurement can then be used to see if the individual is an authorized user. Conventional Diffie-Hellman public key encryption schemes and hashing procedures can then be used to secure the communications lines carrying the biometric information and to secure the database of authorized users.« less

Formal Modeling of Diffie-Hellman Derivability for Exploratory Automated Analysis

DTIC Science & Technology

2013-06-01

monomials (displayed as a column vector for readability): (23) MA(x̄) =  MA1(x̄) MA2 (x̄) ... MAr (x̄)  =  xα111 x α12 2 · · ·xα1nn xα211 x...ȳ β̄ ∈ F[y1, . . . , yr] and A ∈ Mr×n(Z) is such that P (MA1(x̄), MA2 (x̄), . . . ,MAr (x̄)) = 0 then for every γ̄, (28) ∑ β̄·A=γ̄ cβ̄ = 0. An...Corollary 8.3. Suppose (29) R(ȳ) = ∑ β̄ cβ̄Mβ̄(ȳ)∑ β̄ dβ̄Mβ̄(ȳ) ∈ F(y1, . . . , yr), A ∈Mr×n(Z) and γ̄ ∈M1×n(Z) are such that (30) R (MA1(x̄), MA2

Method and system for normalizing biometric variations to authenticate users from a public database and that ensures individual biometric data privacy

DOEpatents

Strait, Robert S.; Pearson, Peter K.; Sengupta, Sailes K.

2000-01-01

A password system comprises a set of codewords spaced apart from one another by a Hamming distance (HD) that exceeds twice the variability that can be projected for a series of biometric measurements for a particular individual and that is less than the HD that can be encountered between two individuals. To enroll an individual, a biometric measurement is taken and exclusive-ORed with a random codeword to produce a "reference value." To verify the individual later, a biometric measurement is taken and exclusive-ORed with the reference value to reproduce the original random codeword or its approximation. If the reproduced value is not a codeword, the nearest codeword to it is found, and the bits that were corrected to produce the codeword to it is found, and the bits that were corrected to produce the codeword are also toggled in the biometric measurement taken and the codeword generated during enrollment. The correction scheme can be implemented by any conventional error correction code such as Reed-Muller code R(m,n). In the implementation using a hand geometry device an R(2,5) code has been used in this invention. Such codeword and biometric measurement can then be used to see if the individual is an authorized user. Conventional Diffie-Hellman public key encryption schemes and hashing procedures can then be used to secure the communications lines carrying the biometric information and to secure the database of authorized users.

Efficiently Multi-User Searchable Encryption Scheme with Attribute Revocation and Grant for Cloud Storage

PubMed Central

Wang, Shangping; Zhang, Xiaoxue; Zhang, Yaling

2016-01-01

Cipher-policy attribute-based encryption (CP-ABE) focus on the problem of access control, and keyword-based searchable encryption scheme focus on the problem of finding the files that the user interested in the cloud storage quickly. To design a searchable and attribute-based encryption scheme is a new challenge. In this paper, we propose an efficiently multi-user searchable attribute-based encryption scheme with attribute revocation and grant for cloud storage. In the new scheme the attribute revocation and grant processes of users are delegated to proxy server. Our scheme supports multi attribute are revoked and granted simultaneously. Moreover, the keyword searchable function is achieved in our proposed scheme. The security of our proposed scheme is reduced to the bilinear Diffie-Hellman (BDH) assumption. Furthermore, the scheme is proven to be secure under the security model of indistinguishability against selective ciphertext-policy and chosen plaintext attack (IND-sCP-CPA). And our scheme is also of semantic security under indistinguishability against chosen keyword attack (IND-CKA) in the random oracle model. PMID:27898703

Efficiently Multi-User Searchable Encryption Scheme with Attribute Revocation and Grant for Cloud Storage.

PubMed

Wang, Shangping; Zhang, Xiaoxue; Zhang, Yaling

2016-01-01

Cipher-policy attribute-based encryption (CP-ABE) focus on the problem of access control, and keyword-based searchable encryption scheme focus on the problem of finding the files that the user interested in the cloud storage quickly. To design a searchable and attribute-based encryption scheme is a new challenge. In this paper, we propose an efficiently multi-user searchable attribute-based encryption scheme with attribute revocation and grant for cloud storage. In the new scheme the attribute revocation and grant processes of users are delegated to proxy server. Our scheme supports multi attribute are revoked and granted simultaneously. Moreover, the keyword searchable function is achieved in our proposed scheme. The security of our proposed scheme is reduced to the bilinear Diffie-Hellman (BDH) assumption. Furthermore, the scheme is proven to be secure under the security model of indistinguishability against selective ciphertext-policy and chosen plaintext attack (IND-sCP-CPA). And our scheme is also of semantic security under indistinguishability against chosen keyword attack (IND-CKA) in the random oracle model.

Authentication Based on Non-Interactive Zero-Knowledge Proofs for the Internet of Things

PubMed Central

Martín-Fernández, Francisco; Caballero-Gil, Pino; Caballero-Gil, Cándido

2016-01-01

This paper describes the design and analysis of a new scheme for the authenticated exchange of confidential information in insecure environments within the Internet of Things, which allows a receiver of a message to authenticate the sender and compute a secret key shared with it. The proposal is based on the concept of a non-interactive zero-knowledge proof, so that in a single communication, relevant data may be inferred to verify the legitimacy of the sender. Besides, the new scheme uses the idea under the Diffie–Hellman protocol for the establishment of a shared secret key. The proposal has been fully developed for platforms built on the Android Open Source Project, so it can be used in any device or sensor with this operating system. This work provides a performance study of the implementation and a comparison between its promising results and others obtained with similar schemes. PMID:26751454

Laboratory for Computer Science Progress Report 18, July 1980-June 1981,

DTIC Science & Technology

1983-04-01

group in collaboration with Rolf Landauer of IBM Research. Some of the most conspicuous participants: Dyson, Feynman, Wheeler Landauer, Keyes, Bennett...Sheldon A. Data Model Equivalence, December 1978, AD A062-753 TM-119 Shamir, Adi and Richard E. Zippel On the Security of the Merkle -Hellman

A Round-Efficient Authenticated Key Agreement Scheme Based on Extended Chaotic Maps for Group Cloud Meeting

PubMed Central

Lee, Tian-Fu; Wang, Zeng-Bo

2017-01-01

The security is a critical issue for business purposes. For example, the cloud meeting must consider strong security to maintain the communication privacy. Considering the scenario with cloud meeting, we apply extended chaotic map to present passwordless group authentication key agreement, termed as Passwordless Group Authentication Key Agreement (PL-GAKA). PL-GAKA improves the computation efficiency for the simple group password-based authenticated key agreement (SGPAKE) proposed by Lee et al. in terms of computing the session key. Since the extended chaotic map has equivalent security level to the Diffie–Hellman key exchange scheme applied by SGPAKE, the security of PL-GAKA is not sacrificed when improving the computation efficiency. Moreover, PL-GAKA is a passwordless scheme, so the password maintenance is not necessary. Short-term authentication is considered, hence the communication security is stronger than other protocols by dynamically generating session key in each cloud meeting. In our analysis, we first prove that each meeting member can get the correct information during the meeting. We analyze common security issues for the proposed PL-GAKA in terms of session key security, mutual authentication, perfect forward security, and data integrity. Moreover, we also demonstrate that communicating in PL-GAKA is secure when suffering replay attacks, impersonation attacks, privileged insider attacks, and stolen-verifier attacks. Eventually, an overall comparison is given to show the performance between PL-GAKA, SGPAKE and related solutions. PMID:29207509

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brickell, E.F.; Davis, J.A.; Simmons, G.J.

A study of the algorithm and the underlying mathematical concepts of A Polynomial Time Algorithm for Breaking Merkle-Hellman Cryptosystems, by Adi Shamir, is presented. Ways of protecting the Merkle-Hellman knapsack from cryptanalysis are given with derivations. (GHT)

Variability of furrow infiltration and irrigation performance in a macroporous soil

USDA-ARS?s Scientific Manuscript database

The study of spatial and temporal variations of infiltration in furrows is essential for the design and management of surface irrigation. A key difficulty in quantifying the process is that infiltration is dependent on the depth of flow, which varies along a furrow and with time. An additional diffi...

Enhancing LoRaWAN Security through a Lightweight and Authenticated Key Management Approach.

PubMed

Sanchez-Iborra, Ramon; Sánchez-Gómez, Jesús; Pérez, Salvador; Fernández, Pedro J; Santa, José; Hernández-Ramos, José L; Skarmeta, Antonio F

2018-06-05

Luckily, new communication technologies and protocols are nowadays designed considering security issues. A clear example of this can be found in the Internet of Things (IoT) field, a quite recent area where communication technologies such as ZigBee or IPv6 over Low power Wireless Personal Area Networks (6LoWPAN) already include security features to guarantee authentication, confidentiality and integrity. More recent technologies are Low-Power Wide-Area Networks (LP-WAN), which also consider security, but present initial approaches that can be further improved. An example of this can be found in Long Range (LoRa) and its layer-two supporter LoRa Wide Area Network (LoRaWAN), which include a security scheme based on pre-shared cryptographic material lacking flexibility when a key update is necessary. Because of this, in this work, we evaluate the security vulnerabilities of LoRaWAN in the area of key management and propose different alternative schemes. Concretely, the application of an approach based on the recently specified Ephemeral Diffie⁻Hellman Over COSE (EDHOC) is found as a convenient solution, given its flexibility in the update of session keys, its low computational cost and the limited message exchanges needed. A comparative conceptual analysis considering the overhead of different security schemes for LoRaWAN is carried out in order to evaluate their benefits in the challenging area of LP-WAN.

Improving the Rainbow Attack by Reusing Colours

NASA Astrophysics Data System (ADS)

Ågren, Martin; Johansson, Thomas; Hell, Martin

Hashing or encrypting a key or a password is a vital part in most network security protocols. The most practical generic attack on such schemes is a time memory trade-off attack. Such an attack inverts any one-way function using a trade-off between memory and execution time. Existing techniques include the Hellman attack and the rainbow attack, where the latter uses different reduction functions ("colours") within a table.

75 FR 28853 - Quarterly Publication of Individuals, Who Have Chosen To Expatriate, as Required by Section 6039G

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-24

.... HECKNER MICHAEL JOHANNES HELLMAN LISA JANE HELLMAN-MERZBACHER JESSICA HENTSCH NIKOLAI HO EUNICE YUK LING... JENNIFER LADANYI HANS GEORG LAMPE ARNO LAUREYNS VEERLE A LEBECH LISA MARGARET LEE YOONBOK STEPHEN LEHMANN... JAMES JOHN MORANT JR PAUL MU DEJUN MULLER SIGRID SIMONS NEDOLUHA DAVID A NEDOLUHA PATRICIA E NEDOLUHA...

Energies of Screened Coulomb Potentials.

ERIC Educational Resources Information Center

Lai, C. S.

1979-01-01

This article shows that, by applying the Hellman-Feynman theorem alone to screened Coulomb potentials, the first four coefficients in the energy series in powers of the perturbation parameter can be obtained from the unperturbed Coulomb system. (Author/HM)

What Is a Developmental-Behavioral Pediatrician?

MedlinePlus

... dyslexia, writing diffi culties, math disorders, and other school-related learning problems Attention and behavioral disorders including attention-deficit/hyperactivity disorder and associated conditions including oppositional-defiant behavior, conduct ...

Magnetic Field Driven Change of the Density of States of Amorphous Gd_xSi_1-x at the Metal Insulator Transition

NASA Astrophysics Data System (ADS)

Teizer, W.; Hellman, F.; Dynes, R. C.; Ucsd Physics Department Collaboration

2000-03-01

We have determined the density of states of amorphous Gd_xSi_1-x, N(E), through the Metal-Insulator transition by tunneling measurements. Gd_xSi_1-x shows a strong negative magnetoresistance at low temperature [1] and can be driven through the Metal-Insulator transition by applying a magnetic field [2]. In H=0, the conductance dI/dV across a Gd_xSi_1-x/oxide/Pb tunnel junction is dominated by a sharp superconducting Pb gap edge and Pb phonons indicating the presence of single step quantum tunneling. As a small magnetic field (H=1kOe) is applied, effects of the superconductivity of Pb disappear and at low voltages it is reasonable to approximate dI/dV N(E). We find that N(E) increases with magnetic field. On the metallic side of the Metal-Insulator transition, the density of states at zero bias, N(0), approximately scales with the extrapolated T=0 transport conductivity σ_0. A change of N(0) thus causes a change in σ_0. The Metal-Insulator transition occurs when N(0) goes to 0. [1] F. Hellman, M. Q. Tran, A. E. Gebala, E. M. Wilcox and R. C. Dynes. Phys. Rev. Lett. bf77, 4652 (1996). P. Xiong, B. I. Zink, S. I. Applebaum, F. Hellman and R. C. Dynes. Phys. Rev. B bf59, 3929 (1999). [2] W. Teizer, F. Hellman and R. C. Dynes. To be published.

Using Web-Based Tools for Teaching Embryology

EPA Science Inventory

Computers, imaging technologies, and the worldwide web have assumed an important role in augmenting traditional learning. Resources to disseminate multimedia information across platforms, and the emergence of communal knowledge environments, facilitate the visualization of diffi...

Studying Intrapersonal Communication through Memoirs and Journals.

ERIC Educational Resources Information Center

Jensen, Marvin D.

One theoretical approach to self-awareness is the study of introspective writing. Among the characteristics of intrapersonal communication that can be explored through memoirs and journals are selective memory and chronology revision. From the reflections of writers like Lillian Hellman, Dag Hammarskjold, and May Sarton comes confirmation that…

An Enhanced Privacy-Preserving Authentication Scheme for Vehicle Sensor Networks

PubMed Central

Zhou, Yousheng; Zhao, Xiaofeng; Jiang, Yi; Shang, Fengjun; Deng, Shaojiang; Wang, Xiaojun

2017-01-01

Vehicle sensor networks (VSNs) are ushering in a promising future by enabling more intelligent transportation systems and providing a more efficient driving experience. However, because of their inherent openness, VSNs are subject to a large number of potential security threats. Although various authentication schemes have been proposed for addressing security problems, they are not suitable for VSN applications because of their high computation and communication costs. Chuang and Lee have developed a trust-extended authentication mechanism (TEAM) for vehicle-to-vehicle communication using a transitive trust relationship, which they claim can resist various attacks. However, it fails to counter internal attacks because of the utilization of a shared secret key. In this paper, to eliminate the vulnerability of TEAM, an enhanced privacy-preserving authentication scheme for VSNs is constructed. The security of our proposed scheme is proven under the random oracle model based on the assumption of the computational Diffie–Hellman problem. PMID:29292792

Knowledge base for v-Embryo: Information Infrastructure for in silico modeling

EPA Science Inventory

Computers, imaging technologies, and the worldwide web have assumed an important role in augmenting traditional learning. Resources to disseminate multimedia information across platforms, and the emergence of communal knowledge environments, facilitate the visualization of diffi...

Trends in personal income and passenger vehicle miles

DOT National Transportation Integrated Search

2007-10-01

While it is diffi cult to predict how individuals will use : increases in their real income in the future, it is clear that : historically some of that increase has been used to acquire : a household vehicle or increase the number of household : vehi...

Automatic Differentiation in Quantum Chemistry with Applications to Fully Variational Hartree-Fock.

PubMed

Tamayo-Mendoza, Teresa; Kreisbeck, Christoph; Lindh, Roland; Aspuru-Guzik, Alán

2018-05-23

Automatic differentiation (AD) is a powerful tool that allows calculating derivatives of implemented algorithms with respect to all of their parameters up to machine precision, without the need to explicitly add any additional functions. Thus, AD has great potential in quantum chemistry, where gradients are omnipresent but also difficult to obtain, and researchers typically spend a considerable amount of time finding suitable analytical forms when implementing derivatives. Here, we demonstrate that AD can be used to compute gradients with respect to any parameter throughout a complete quantum chemistry method. We present DiffiQult , a Hartree-Fock implementation, entirely differentiated with the use of AD tools. DiffiQult is a software package written in plain Python with minimal deviation from standard code which illustrates the capability of AD to save human effort and time in implementations of exact gradients in quantum chemistry. We leverage the obtained gradients to optimize the parameters of one-particle basis sets in the context of the floating Gaussian framework.

Automatic Differentiation in Quantum Chemistry with Applications to Fully Variational Hartree–Fock

PubMed Central

2018-01-01

Automatic differentiation (AD) is a powerful tool that allows calculating derivatives of implemented algorithms with respect to all of their parameters up to machine precision, without the need to explicitly add any additional functions. Thus, AD has great potential in quantum chemistry, where gradients are omnipresent but also difficult to obtain, and researchers typically spend a considerable amount of time finding suitable analytical forms when implementing derivatives. Here, we demonstrate that AD can be used to compute gradients with respect to any parameter throughout a complete quantum chemistry method. We present DiffiQult, a Hartree–Fock implementation, entirely differentiated with the use of AD tools. DiffiQult is a software package written in plain Python with minimal deviation from standard code which illustrates the capability of AD to save human effort and time in implementations of exact gradients in quantum chemistry. We leverage the obtained gradients to optimize the parameters of one-particle basis sets in the context of the floating Gaussian framework.

Fatigue Assessment: Subjective Peer-to-Peer Fatigue Scoring (Reprint)

DTIC Science & Technology

2013-10-01

impor- tant role of fatigue in aviation safety and fl ight perfor- mance, the compelling tasks of predicting dangerous fatigued states and quantifying ... risk and associated per- formance defi cits have been immoderately diffi cult. This is particularly true for an individual functioning within the

A landscape approach for assessing the ecological feasibility of a black bear population recovery

EPA Science Inventory

There is great interest in recovering populations of large carnivores in locations where they previously were extirpated or severely reduced in size as a result of human activity. Determining the ecological feasibility (i.e., is adequate habitat available?) of a species is diffi...

Biological rhythms and rotating shift work : some considerations for air traffic controllers and managers.

DOT National Transportation Integrated Search

1986-01-01

This report is a general review of some of the current themes and practices regarding rotating shift work; to inform air traffic controllers, technicians, and managers of these issues; and to offer some ideas that may be helpful in dealing with diffi...

Hypersonic Flight Test Windows for Technology Development Testing

DTIC Science & Technology

2013-11-01

used. 2.1 Propulsion and Controls Test Window The technologies dealing with scramjet propulsion (inlets, fuel injection, etc.) and hypersonic ...AFRL-RQ-WP-TM-2013-0260 HYPERSONIC FLIGHT TEST WINDOWS FOR TECHNOLOGY DEVELOPMENT TESTING Barry M. Hellman Vehicle Technology Branch...DATES COVERED (From - To) November 2013 Final 01 November 2013 – 25 November 2013 4. TITLE AND SUBTITLE HYPERSONIC FLIGHT TEST WINDOWS FOR

Integrated Approach to User Account Management

NASA Technical Reports Server (NTRS)

Kesselman, Glenn; Smith, William

2007-01-01

IT environments consist of both Windows and other platforms. Providing user account management for this model has become increasingly diffi cult. If Microsoft#s Active Directory could be enhanced to extend a W indows identity for authentication services for Unix, Linux, Java and Macintosh systems, then an integrated approach to user account manag ement could be realized.

Dual Nitrate Isotopes in Dry Deposition: Utility for Partitioning Nox Source Contributions to Landscape Nitrogen Deposition

EPA Science Inventory

Dry deposition is a major component of total nitrogen deposition and thus an important source of bioavailable nitrogen to ecosystems. However, relative to wet deposition, less is known regarding the sources and spatial variability of dry deposition. This is in part due to diffi...

Shannon Entropy of Ammonia Volatilization from Fertilized Agricultural Soils

USDA-ARS?s Scientific Manuscript database

The economic loss of ammonia (NH3) volatilization from chemical N fertilizers applied to farmlands worldwide is 11.6 billion US dollars per year. The economic impact of negative environmental effects resulted from NH3 volatilization, i.e., formation of potent greenhouse gas (N2O) and PM2.5, is diffi...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deshmukh, Ranjit; Bharvirkar, Ranjit; Gambhir, Ashwin

Although solar costs are dropping rapidly, solar power is still more expensive than conventional and other renewable energy options. The solar sector still needs continuing government policy support. These policies are driven by objectives that go beyond the goal of achieving grid parity. The need to achieve multiple objectives and ensure sufficient political support for solar power makes it diffi cult for policy makers to design the optimal solar power policy. The dynamic and uncertain nature of the solar industry, combined with the constraints offered by broader economic, political and social conditions further complicates the task of policy making. Thismore » report presents an analysis of solar promotion policies in seven countries - Germany, Spain, the United States, Japan, China, Taiwan, and India - in terms of their outlook, objectives, policy mechanisms and outcomes. The report presents key insights, primarily in qualitative terms, and recommendations for two distinct audiences. The first audience consists of global policy makers who are exploring various mechanisms to increase the penetration of solar power in markets to mitigate climate change. The second audience consists of key Indian policy makers who are developing a long-term implementation plan under the Jawaharlal Nehru National Solar Mission and various state initiatives.« less

Berkeley Lab - Materials Sciences Division

Science.gov Websites

Berkeley Lab Berkeley Lab A-Z Index Phone Book Jobs Search DOE Search MSD Go MSD - Materials Investigators Ager, Joel W » Alivisatos, A Paul » Altman, Ehud » Analytis, James » Anderson, Christopher  , Naomi » Gullikson, Eric M » Harris, Stephen J » Hasan, M. Zahid » Hellman, Frances » Helms, Brett A

Age Effect on Autonomic Cardiovascular Control in Pilots

DTIC Science & Technology

2000-08-01

Nantcheva**, M. Vukov *** *National Center of Hygiene, Medical Ecology and Nutrition 15 Dimitar Nestorov Blvd. 1431 Sofia, Bulgaria "**Military Medical...values and critique. Inter. Physiol. Behav. Sci. 1997, 3, of health risk compared with referents. 202-219. 14. Fluckiger L., Boivin J ., Quilliot D...during flight. Aviat. Space Chapman and Hall. 1991, 590 pp. Environ Med. 1998,4, 360-367. 4. Berntson G., Cacioppo J ., Quigley K. Autonomic 18. Hellman J

Key Exchange Trust Evaluation in Peer-to-Peer Sensor Networks With Unconditionally Secure Key Exchange

NASA Astrophysics Data System (ADS)

Gonzalez, Elias; Kish, Laszlo B.

2016-03-01

As the utilization of sensor networks continue to increase, the importance of security becomes more profound. Many industries depend on sensor networks for critical tasks, and a malicious entity can potentially cause catastrophic damage. We propose a new key exchange trust evaluation for peer-to-peer sensor networks, where part of the network has unconditionally secure key exchange. For a given sensor, the higher the portion of channels with unconditionally secure key exchange the higher the trust value. We give a brief introduction to unconditionally secured key exchange concepts and mention current trust measures in sensor networks. We demonstrate the new key exchange trust measure on a hypothetical sensor network using both wired and wireless communication channels.

National Strategy for Homeland Security

DTIC Science & Technology

2007-10-01

biometrics, including in passports and visas, has made it increasingly diffi- cult to counterfeit travel docu- ments, and we must encourage those... counterfeiting , altera- tion, and misuse of identifica- tion and travel documents, and to report lost and stolen passports in a timely manner. These efforts...in medicine , agriculture, and industry. We will stringently enforce our export control laws as a means of denying rogue actors – including

Holistic Contract Administration in Army Forces Abroad

DTIC Science & Technology

2016-10-01

Defense (DoD) civil- ian personnel—i.e., 1910 Quality Assurance Specialist, 1102 Contract Specialist, and 1103 Industrial Property Management Specialist... 1103 -series civilian property ad- ministrators throughout ACC, the battalion experienced diffi- culties hiring for these positions during its deployment...tasks. Counting on 1103 support, ACOs received minimal property training prior to deploy- ment. This proved to be a major setback as ACOs struggled

Reinforcer Accumulation in a Token-Reinforcement Context with Pigeons

ERIC Educational Resources Information Center

Yankelevitz, Rachelle L.; Bullock, Christopher E.; Hackenberg, Timothy D.

2008-01-01

Four pigeons were exposed to a token-reinforcement procedure with stimulus lights serving as tokens. Responses on one key (the token-production key) produced tokens that could be exchanged for food during an exchange period. Exchange periods could be produced by satisfying a ratio requirement on a second key (the exchange-production key). The…

Garment Selection for Cleanrooms and Controlled Environments for Spacecraft

DTIC Science & Technology

1991-04-01

visually undetectable, making it diffi- cult for a worker to select a treated garment. The optimal solution has been to weave a grid of synthetic coated ...make the base fabric static-dis- sipative must be selected carefully. Nylon- coated conductive yarns are readily subject to acid attack, while...Cations (+ ) which must be eliminated from garments include sodium, potassium, lithi- um, aluminum, boron , and arsenic. The standard mtwhod for

JPRS Report, China

DTIC Science & Technology

1991-02-14

payments are due as stipulated in the national debt- for the better in the market slump, and there will still be payment program. The banks are responsible ...pluck up met, as well as the demands on the international market . their courage and confidence in conquering their diffi- The adjustment of the product...ruled that those involved in and which planned prices were primary and market regula- those responsible for adulteration and deception when tion prices

JPRS Report, China.

DTIC Science & Technology

1989-03-23

economic reform, the price hikes of some major consumer goods over the past 2 years have reached double digits.) There is another example regarding a...of this staple to eat. For urban residents, rationing now ensures a guar- anteed supply of grain at stable prices , so the greatest impact on...States was bogged down in the quagmire of the Vietnam war, faced both domestic and external diffi- culty, and was forced into strategic withdrawal. Mean

The Budget and Economic Outlook: 2015 to 2025

DTIC Science & Technology

2015-01-01

States. 19. In principle , GDI equals GDP, because each dollar of production yields a dollar of income; in practice, they differ because of diffi...Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour...and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information

Microbiological Evaluation of Containment Isolators for the Care of Patients with Exotic Diseases.

DTIC Science & Technology

1980-02-01

The microbiological integrity of containment isolators obtained from Vickers Limited Medical Engineering was evaluated using aerosols of Tl coliphage ...diluted in sterile distilled water (SDW). Aliquots for plate counts were mixed with log phase host cells and the mixture spread evenly on pre-dried...of water was diffi- cult to maintain and measure accurately even with sensitive meters, and finally visual observation of the curvature of the side

AGARD Flight Test Instrumentation Series. Volume 8. Linear and Angular Position Measurement of Aircraft Components

DTIC Science & Technology

1977-01-01

art=m The Netherlands 1.0 ] I This volwme concentrates on flight teat instrumentation for determining the position of movable air - craft components...form an integral part of a transducer. The discussion in this volume has been limited to measurements of the relative positions of two air - crft...often cause diffi ties. Special types, for instance, the brushless types, can be used at higher temperatures up to about 3000 C. Chaning the

Worldwide Report, Epidemiology, No. 327.

DTIC Science & Technology

1983-08-10

20 Briefs Dengue Fever in Michoacan 21 Tuberculosis in Chiapas 21 PAKISTAN 20-Year Program To Eradicate Tuberculosis (DAWN, 6 Jul 83) 22...EXCELSIOR in Spanish 23 Jun 83 p 6] 8255 TUBERCULOSIS IN CHIAPAS —Tuxtla Gutierrez, Chis., June 18—It is very diffi- cult to confirm that 40 per cent of...actual tuberculosis figure for the Chiapas area fluctuates between 15 and 20 per cent of the population, but that the utmost has been done to

Characterization of the Pathological and Biochemical Markers that Correlate to the Clinical Features of Autism: The Neuropathological Markers of Abnormal Brain Development and Aging in Autism

DTIC Science & Technology

2010-10-21

generalization of previously acquired skills, (f) rigidity and resistance to change, (g) social and communication defi cits, and (h) diffi culty in...defects and three diagnostic domains of autism (social and communication deficits, and ritualistic behaviors) and intellectual deficits. This process is...including: (a) qualitative impairments in reciprocal social interactions, (b) qualitative impairments in verbal and nonverbal communication , (c

Individual Differences in Dual Task Performance.

DTIC Science & Technology

1981-06-10

SJCURITY CLASSIFICATION OF THIS PAGE("en Data Entered) second experimental series, we compared ability to detect visual and audi- tory targets in single...used performance on a simple secondary task executed during an easy primary task to predict performance on a more diffi- cult’version of the same...process concepts developed b’j cognitive ps:choloqists°’ In this laborators, we adapted a number of experimental tasks to 4ield individual measures of the

An Approach to the Comparative Analysis of the US and Soviet Economies.

DTIC Science & Technology

1980-09-01

compare aithority exer:isud in different forms is hasic. Designing such a i,,easuring system necessitates development of a weighting system to measure the...Proper flie maintenance is diffi,.lt 34 a because of poor file organization, inade;tiately designed inflow of updating information, and manual methods...asiSsnet 5.1 Issues Areas for Comparative Analysis Comparativ ,. issioes relatc to i, soc-cicty’s mobjilization of resources and use of institution’, Lo a

X-Ray System, Lightweight Medical (XRSLM)

DTIC Science & Technology

1992-08-10

AD-25805 DTIC ELECTE DEC 3 1992 C~ontract No. DAMD 17-88(1-8058 X-Ray System , Lightweight Medical kXRSLM) M el in P .Siedba nl Frank C. G-reuzow’)N...Craig A. Hellman Robert C. Bruce rl 4 1W ý~( rf A&*- ~ko~.$~._ LO Contract No. DAMD17-88C-8058 X-Ray System , Lightweight Medical (XRSLM) Melvin P... System , Lightweight Medical (XRSLM) Contract No. DAMD17-88-C-805 8 6. AUTHOR(S)Melvin P. Siedband 63807A Frank C. Grenzow 3M463807L2336 HE 041 Craig A

Quantum cryptography to satellites for global secure key distribution

NASA Astrophysics Data System (ADS)

Rarity, John G.; Gorman, Philip M.; Knight, Paul; Wallace, Kotska; Tapster, Paul R.

2017-11-01

We have designed and built a free space secure key exchange system using weak laser pulses with polarisation modulation by acousto-optic switching. We have used this system to exchange keys over a 1.2km ground range with absolute security. Building from this initial result we analyse the feasibility of exchanging keys to a low earth orbit satellite.

Medical Effects and Dosimetric Data from Nuclear Tests at the Semipalatinsk Test Site

DTIC Science & Technology

2006-06-01

fi bromyoma 8 10 4 Posthysterectomy changes (radical hys- terectomy for cancer) 5 7 2 Displaced sex organs 3 11 7 Uterine prolapse and varicose...dust, of diffi culty in breathing, and eye irritation. The skies were overcast and dusk fell; the cattle were restless, and howling dogs , their...11 Chronic adnexitis 32 54 42 Cervicitis 19 32 17 Endocervicitis 6 16 6 Fibrocystic changes of the ovary 4 5 -- Cervical canal polyps 2 2 6 Uterine

Deaths by Suicide While on Active Duty, Active and Reserve Components, U.S. Armed Forces, 1998-2011

DTIC Science & Technology

2012-06-01

June 2012 Vol. 19 No. 6 M S M R Page 7 have suggested that deployment to these confl icts increases a soldier’s risk of suicide and have...estimated a proportion of suicides that may be related to deployment.6,10 Such relationships are plausible but diffi cult to characterize precisely...because many cor- relates of risk for suicide are closely associ- ated with wartime deployments (e.g., access to weapons, high operational tempos

Human Factors Affecting Pilot Performance in Vertical and Translational Instrument Flight

DTIC Science & Technology

1986-01-01

purpose of a mission lie all the areas of information which together result in the accomplished flight. Since the only courve of’ action open to a pilot...any of these cases there is a diffi’cult t radeoff between the desire to present the largest possible outside angular representation ( field of view...is an urgent program to implement the cockpit display of traffic information (CDTL). Practical limitations on the fields of view of vertical situation

Conservative Management of Uncomplicated Mechanical Neck Pain in a Military Aviator

DTIC Science & Technology

2010-01-01

head to the right. The neck pain became more bothersome during and after ACM. Typically the pain was described as being dull and aching in...outcome of exposure to high gravi- tational (G) forces.2 The weight of the helmet and oxygen mask and the various non-neutral head postures assumed when...character; however it could become sharp with rapid right rotation of the neck or under high G situations. He experienced diffi culty turning his head to

Bidirectional private key exchange using delay-coupled semiconductor lasers.

PubMed

Porte, Xavier; Soriano, Miguel C; Brunner, Daniel; Fischer, Ingo

2016-06-15

We experimentally demonstrate a key exchange cryptosystem based on the phenomenon of identical chaos synchronization. In our protocol, the private key is symmetrically generated by the two communicating partners. It is built up from the synchronized bits occurring between two current-modulated bidirectionally coupled semiconductor lasers with additional self-feedback. We analyze the security of the exchanged key and discuss the amplification of its privacy. We demonstrate private key generation rates up to 11  Mbit/s over a public channel.

The surface of Mars: An unusual laboratory that preserves a record of catastrophic and unusual events

USGS Publications Warehouse

Chapman, M.G.

2009-01-01

Catastrophic and unusual events on Earth such as bolide impacts, megafloods, supereruptions, flood volcanism, and subice volcanism may have devastating effects when they occur. Although these processes have unique characteristics and form distinctive features and deposits, we have diffi culties identifying them and measuring the magnitude of their effects. Our diffi culties with interpreting these processes and identifying their consequences are understandable considering their infrequency on Earth, combined with the low preservation potential of their deposits in the terrestrial rock record. Although we know these events do happen, they are infrequent enough that the deposits are poorly preserved on the geologically active face of the Earth, where erosion, volcanism, and tectonism constantly change the surface. Unlike the Earth, on Mars catastrophic and unusual features are well preserved because of the slow modifi cation of the surface. Signifi cant precipitation has not occurred on Mars for billions of years and there appears to be no discrete crustal plates to have undergone subduction and destruction. Therefore the ancient surface of Mars preserves geologic features and deposits that result from these extraordinary events. Also, unlike the other planets, Mars is the most similar to our own, having an atmosphere, surface ice, volcanism, and evidence of onceflowing water. So although our understanding of precursors, processes, and possible biological effects of catastrophic and unusual processes is limited on Earth, some of these mysteries may be better understood through investigating the surface of Mars. ?? 2009 The Geological Society of America.

On the security of a simple three-party key exchange protocol without server's public keys.

PubMed

Nam, Junghyun; Choo, Kim-Kwang Raymond; Park, Minkyu; Paik, Juryon; Won, Dongho

2014-01-01

Authenticated key exchange protocols are of fundamental importance in securing communications and are now extensively deployed for use in various real-world network applications. In this work, we reveal major previously unpublished security vulnerabilities in the password-based authenticated three-party key exchange protocol according to Lee and Hwang (2010): (1) the Lee-Hwang protocol is susceptible to a man-in-the-middle attack and thus fails to achieve implicit key authentication; (2) the protocol cannot protect clients' passwords against an offline dictionary attack; and (3) the indistinguishability-based security of the protocol can be easily broken even in the presence of a passive adversary. We also propose an improved password-based authenticated three-party key exchange protocol that addresses the security vulnerabilities identified in the Lee-Hwang protocol.

On the Security of a Simple Three-Party Key Exchange Protocol without Server's Public Keys

PubMed Central

Nam, Junghyun; Choo, Kim-Kwang Raymond; Park, Minkyu; Paik, Juryon; Won, Dongho

2014-01-01

Authenticated key exchange protocols are of fundamental importance in securing communications and are now extensively deployed for use in various real-world network applications. In this work, we reveal major previously unpublished security vulnerabilities in the password-based authenticated three-party key exchange protocol according to Lee and Hwang (2010): (1) the Lee-Hwang protocol is susceptible to a man-in-the-middle attack and thus fails to achieve implicit key authentication; (2) the protocol cannot protect clients' passwords against an offline dictionary attack; and (3) the indistinguishability-based security of the protocol can be easily broken even in the presence of a passive adversary. We also propose an improved password-based authenticated three-party key exchange protocol that addresses the security vulnerabilities identified in the Lee-Hwang protocol. PMID:25258723

Effects of Atmospheric Water Vapor and Clouds on NOAA (National Oceanic and Atmospheric Administration) AVHRR (Advanced Very High Resolution Radiometer) Satellite Data.

DTIC Science & Technology

1984-07-01

aerosols and sub pixel-sized clouds all tend to increase Channel 1 with respect to Channel 2 and reduce the computed VIN. Further, the Guide states that... computation of the VIN. Large scale cloud contamination of pixels, while diffi- cult to correct for, can at least be monitored and affected pixels...techniques have been developed for computer cloud screening. See, for example, Horvath et al. (1982), Gray and McCrary (1981a) and Nixon et al. (1983

Partial Reform Equilibrium in Russia: A Case Study of the Political Interests of and in the Russian Gas and Oil Industry

NASA Astrophysics Data System (ADS)

Everett, Rabekah

While several theories abound that attempt to explain the obstacles to democracy in Russia, Joel Hellman's partial reform equilibrium model is an institutional theory that illustrates how weak institutions, combined with an instrumentalist cultural approach to the law and authoritarian-minded leadership, allowed the struggle over interests to craft and determine the nature of Russia's political structure. This thesis builds on the work of Hellman by using the partial reform theory to understand the evolution of interest infiltration and their impact on the formation of policies and institutions in favour of the elites or winners from 2004 to the present time period that allow them to wield law as a political weapon. The hypothesis posits that through their vested interests in state politics, the political and economic elites of the oil and gas industry have successfully stalled reform in Russia resulting in partial reform equilibrium. This is illustrated in a case study that was designed to collect the names, backgrounds, and social networks of gas and oil executives in order to determine how many of them have a history of, or are currently working as, ministers in the government or representatives in the Federation Council. The objective being to measure the degree to which gas and oil interests are present in government decision-making and conversely, the degree to which the government is present in the gas and oil industry. The thesis stresses the importance of institutional structure in determining Russia's political evolution, and uses vested interests as a primary source of structural institutional change, while also stressing on the social and international implications of this evolution.

Key exchange using biometric identity based encryption for sharing encrypted data in cloud environment

NASA Astrophysics Data System (ADS)

Hassan, Waleed K.; Al-Assam, Hisham

2017-05-01

The main problem associated with using symmetric/ asymmetric keys is how to securely store and exchange the keys between the parties over open networks particularly in the open environment such as cloud computing. Public Key Infrastructure (PKI) have been providing a practical solution for session key exchange for loads of web services. The key limitation of PKI solution is not only the need for a trusted third partly (e.g. certificate authority) but also the absent link between data owner and the encryption keys. The latter is arguably more important where accessing data needs to be linked with identify of the owner. Currently available key exchange protocols depend on using trusted couriers or secure channels, which can be subject to man-in-the-middle attack and various other attacks. This paper proposes a new protocol for Key Exchange using Biometric Identity Based Encryption (KE-BIBE) that enables parties to securely exchange cryptographic keys even an adversary is monitoring the communication channel between the parties. The proposed protocol combines biometrics with IBE in order to provide a secure way to access symmetric keys based on the identity of the users in unsecure environment. In the KE-BIOBE protocol, the message is first encrypted by the data owner using a traditional symmetric key before migrating it to a cloud storage. The symmetric key is then encrypted using public biometrics of the users selected by data owner to decrypt the message based on Fuzzy Identity-Based Encryption. Only the selected users will be able to decrypt the message by providing a fresh sample of their biometric data. The paper argues that the proposed solution eliminates the needs for a key distribution centre in traditional cryptography. It will also give data owner the power of finegrained sharing of encrypted data by control who can access their data.

Energetics of Nanomaterials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hellman, Frances

2004-12-13

This project, ''Energetics of Nanomaterials'', represents a three-year collaboration among Alexandra Navrotsky (University of California at Davis), Brian Woodfield and Juliana Boerio-Goates (Brigham Young University) and Frances Hellman (University of California at San Diego). Its purpose has been to explore the differences between bulk materials, nanoparticles, and thin films in terms of their thermodynamic properties, with an emphasis on heat capacities and entropies, as well as enthalpies. We used our combined experimental techniques to address the following questions: How does energy and entropy depend on particle size and crystal structure? Do entropic differences have their origins in changes in vibrationalmore » densities of states or configurational (including surface configuration) effects? Do material preparation and sample geometry, i.e., nanoparticles versus thin films, change these quantities? How do the thermodynamics of magnetic and structural transitions change in nanoparticles and thin films? Are different crystal structures stabilized for a given composition at the nanoscale, and are the responsible factors energetic, entropic, or both? How do adsorption energies (for water and other gases) depend on particle size and crystal structure in the nanoregime? What are the energetics of formation and strain energies in artificially layered thin films? Do the differing structures of grain boundaries in films and nanocomposites alter the energetics of nanoscale materials? Of the several directions we first proposed, we initially concentrated on a few systems: TiO(sub 2), CoO, and CoO-MgO. In these systems, we were able to clearly identify particle size-dependent effects on energy and vibrational entropy, and to separate out the effect of particle size and water content on the enthalpy of formation of the various TiO(sub 2) polymorphs. With CoO, we were able to directly compare nanoparticle films and bulk materials; this comparison is important because films can be either 2 dimensional structures, limited by thickness, or can be dominated by nanoparticle granular behavior. These materials represent good model systems which are relevant to technological and geochemical applications as well as to the fundamental underlying science. The collaboration was both congenial and fruitful. We exchanged both samples and scholars among the laboratories. We met several times a year, rotating these meetings among the three institutions. We had frequent conference calls and were in constant email contact. We learned an immense amount from each other because we brought not just different methodologies but different disciplines to the project. In particular, the interplay of physics (Hellman), chemistry (Woodfield, Boerio-Goates, Navrotsky) and geochemistry (Navrotsky) viewpoints has been very enriching. The result has been a number of publications already in print, and several more in preparation, graduate student PhD and MS degrees, and undergraduate research students supported, as well as a well-developed collaboration that will lead to even more fruitful and important science in the coming years.« less

78 FR 23969 - Ewan 1, INC. n/k/a AccessKey IP, Inc.; Order of Suspension of Trading

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-23

... SECURITIES AND EXCHANGE COMMISSION [File No. 500-1] Ewan 1, INC. n/k/a AccessKey IP, Inc.; Order of Suspension of Trading April 19, 2013. It appears to the Securities and Exchange Commission that... AccessKey IP, Inc. (``AccessKey'') because it has not filed a periodic report since it filed its...

A broadcast-based key agreement scheme using set reconciliation for wireless body area networks.

PubMed

Ali, Aftab; Khan, Farrukh Aslam

2014-05-01

Information and communication technologies have thrived over the last few years. Healthcare systems have also benefited from this progression. A wireless body area network (WBAN) consists of small, low-power sensors used to monitor human physiological values remotely, which enables physicians to remotely monitor the health of patients. Communication security in WBANs is essential because it involves human physiological data. Key agreement and authentication are the primary issues in the security of WBANs. To agree upon a common key, the nodes exchange information with each other using wireless communication. This information exchange process must be secure enough or the information exchange should be minimized to a certain level so that if information leak occurs, it does not affect the overall system. Most of the existing solutions for this problem exchange too much information for the sake of key agreement; getting this information is sufficient for an attacker to reproduce the key. Set reconciliation is a technique used to reconcile two similar sets held by two different hosts with minimal communication complexity. This paper presents a broadcast-based key agreement scheme using set reconciliation for secure communication in WBANs. The proposed scheme allows the neighboring nodes to agree upon a common key with the personal server (PS), generated from the electrocardiogram (EKG) feature set of the host body. Minimal information is exchanged in a broadcast manner, and even if every node is missing a different subset, by reconciling these feature sets, the whole network will still agree upon a single common key. Because of the limited information exchange, if an attacker gets the information in any way, he/she will not be able to reproduce the key. The proposed scheme mitigates replay, selective forwarding, and denial of service attacks using a challenge-response authentication mechanism. The simulation results show that the proposed scheme has a great deal of adoptability in terms of security, communication overhead, and running time complexity, as compared to the existing EKG-based key agreement scheme.

Comparative study of key exchange and authentication methods in application, transport and network level security mechanisms

NASA Astrophysics Data System (ADS)

Fathirad, Iraj; Devlin, John; Jiang, Frank

2012-09-01

The key-exchange and authentication are two crucial elements of any network security mechanism. IPsec, SSL/TLS, PGP and S/MIME are well-known security approaches in providing security service to network, transport and application layers; these protocols use different methods (based on their requirements) to establish keying materials and authenticates key-negotiation and participated parties. This paper studies and compares the authenticated key negotiation methods in mentioned protocols.

An update on the BQCD Hybrid Monte Carlo program

NASA Astrophysics Data System (ADS)

Haar, Taylor Ryan; Nakamura, Yoshifumi; Stüben, Hinnerk

2018-03-01

We present an update of BQCD, our Hybrid Monte Carlo program for simulating lattice QCD. BQCD is one of the main production codes of the QCDSF collaboration and is used by CSSM and in some Japanese finite temperature and finite density projects. Since the first publication of the code at Lattice 2010 the program has been extended in various ways. New features of the code include: dynamical QED, action modification in order to compute matrix elements by using Feynman-Hellman theory, more trace measurements (like Tr(D-n) for K, cSW and chemical potential reweighting), a more flexible integration scheme, polynomial filtering, term-splitting for RHMC, and a portable implementation of performance critical parts employing SIMD.

KeySlinger and StarSlinger: Secure Key Exchange and Encrypted File Transfer on Smartphones

DTIC Science & Technology

2011-05-01

format data to exchange because contact information can be exported to V- Cards using existing APIs. For these reasons it was chosen as the medium to... Card format allows customization of this field. The service provider field serves to identify the app the key is for and the username field stores the...public key data. A sample V- Card field looks like Listing 1 below. IMPP;TextSecure

October 2003 Maine DOT research peer exchange.

DOT National Transportation Integrated Search

2003-10-01

A theme or focus area for this exchange was to follow NCHRP Synthesis 280, Seven : Keys to Building a Robust Research Program. These keys are: : 1. Found it on trust Ensure a trusting relationship between research unit and : department. : 2. Mark...

The impact of economic and noneconomic exchange on physicians' organizational attitudes: The moderating effects of the Chief Medical Officer.

PubMed

Trybou, Jeroen; Gemmel, Paul; Annemans, Lieven

2016-01-01

Hospital-physician relationships are critical to hospitals' organizational success. A distinction can be drawn between economic and noneconomic physician-hospital exchange. Physician senior leadership could be an important component of managerial strategies aimed at optimizing hospital-physician relationships. The purpose of this study was to investigate the moderating role of the quality of exchange with the Chief Medical Officer (CMO) in the relationship between economic and noneconomic exchange and physicians' key organizational attitudes. Self-employed physicians practicing at six Belgian hospitals were surveyed. Economic exchange was conceptualized by the concepts of distributive and procedural justice, whereas noneconomic exchange was conceptualized by the concepts of administrative and professional psychological contract. Our outcomes comprise three key organizational attitudes identified in the literature (job satisfaction, affective organizational commitment, and intention to leave). The moderating role of leader-member exchange with the CMO in these relationships was assessed. Our results showed a relationship between both psychological contract breach and organizational justice and physicians' organizational attitudes. The quality of exchange with the CMO buffered the negative effect of psychological contract breach and reinforced the positive effects of organizational justice with respect to physicians' organizational attitudes. Our results demonstrate that both economic and noneconomic aspects are important when considering physicians' key organizational attitudes. The reciprocity dynamic between physician and hospital can be enhanced by high-quality exchange with the CMO.

Conceptual DFT analysis of the fragility spectra of atoms along the minimum energy reaction coordinate.

PubMed

Ordon, Piotr; Komorowski, Ludwik; Jedrzejewski, Mateusz

2017-10-07

Theoretical justification has been provided to the method for monitoring the sequence of chemical bonds' rearrangement along a reaction path, by tracing the evolution of the diagonal elements of the Hessian matrix. Relations between the divergences of Hellman-Feynman forces and the energy and electron density derivatives have been demonstrated. By the proof presented on the grounds of the conceptual density functional theory formalism, the spectral amplitude observed on the atomic fragility spectra [L. Komorowski et al., Phys. Chem. Chem. Phys. 18, 32658 (2016)] reflects selectively the electron density modifications in bonds of an atom. In fact the spectral peaks for an atom reveal changes of the electron density occurring with bonds creation, breaking, or varying with the reaction progress.

Conceptual DFT analysis of the fragility spectra of atoms along the minimum energy reaction coordinate

NASA Astrophysics Data System (ADS)

Ordon, Piotr; Komorowski, Ludwik; Jedrzejewski, Mateusz

2017-10-01

Theoretical justification has been provided to the method for monitoring the sequence of chemical bonds' rearrangement along a reaction path, by tracing the evolution of the diagonal elements of the Hessian matrix. Relations between the divergences of Hellman-Feynman forces and the energy and electron density derivatives have been demonstrated. By the proof presented on the grounds of the conceptual density functional theory formalism, the spectral amplitude observed on the atomic fragility spectra [L. Komorowski et al., Phys. Chem. Chem. Phys. 18, 32658 (2016)] reflects selectively the electron density modifications in bonds of an atom. In fact the spectral peaks for an atom reveal changes of the electron density occurring with bonds creation, breaking, or varying with the reaction progress.

Three-party authenticated key agreements for optimal communication

PubMed Central

Lee, Tian-Fu; Hwang, Tzonelih

2017-01-01

Authenticated key agreements enable users to determine session keys, and to securely communicate with others over an insecure channel via the session keys. This study investigates the lower bounds on communications for three-party authenticated key agreements and considers whether or not the sub-keys for generating a session key can be revealed in the channel. Since two clients do not share any common secret key, they require the help of the server to authenticate their identities and exchange confidential and authenticated information over insecure networks. However, if the session key security is based on asymmetric cryptosystems, then revealing the sub-keys cannot compromise the session key. The clients can directly exchange the sub-keys and reduce the transmissions. In addition, authenticated key agreements were developed by using the derived results of the lower bounds on communications. Compared with related approaches, the proposed protocols had fewer transmissions and realized the lower bounds on communications. PMID:28355253

Knowledge exchange systems for youth health and chronic disease prevention: a tri-provincial case study.

PubMed

Murnaghan, D; Morrison, W; Griffith, E J; Bell, B L; Duffley, L A; McGarry, K; Manske, S

2013-09-01

The research teams undertook a case study design using a common analytical framework to investigate three provincial (Prince Edward Island, New Brunswick and Manitoba) knowledge exchange systems. These three knowledge exchange systems seek to generate and enhance the use of evidence in policy development, program planning and evaluation to improve youth health and chronic disease prevention. We applied a case study design to explore the lessons learned, that is, key conditions or processes contributing to the development of knowledge exchange capacity, using a multi-data collection method to gain an in-depth understanding. Data management, synthesis and analysis activities were concurrent, iterative and ongoing. The lessons learned were organized into seven "clusters." Key findings demonstrated that knowledge exchange is a complex process requiring champions, collaborative partnerships, regional readiness and the adaptation of knowledge exchange to diverse stakeholders. Overall, knowledge exchange systems can increase the capacity to exchange and use evidence by moving beyond collecting and reporting data. Areas of influence included development of new partnerships, expanded knowledge-sharing activities, and refinement of policy and practice approaches related to youth health and chronic disease prevention.

Bi-directional exchange of ammonia in a pine forest ecosystem - a model sensitivity analysis

NASA Astrophysics Data System (ADS)

Moravek, Alexander; Hrdina, Amy; Murphy, Jennifer

2016-04-01

Ammonia (NH3) is a key component in the global nitrogen cycle and of great importance for atmospheric chemistry, neutralizing atmospheric acids and leading to the formation of aerosol particles. For understanding the role of NH3 in both natural and anthropogenically influenced environments, the knowledge of processes regulating its exchange between ecosystems and the atmosphere is essential. A two-layer canopy compensation point model is used to evaluate the NH3 exchange in a pine forest in the Colorado Rocky Mountains. The net flux comprises the NH3 exchange of leaf stomata, its deposition to leaf cuticles and exchange with the forest ground. As key parameters the model uses in-canopy NH3 mixing ratios as well as leaf and soil emission potentials measured at the site in summer 2015. A sensitivity analysis is performed to evaluate the major exchange pathways as well as the model's constraints. In addition, the NH3 exchange is examined for an extended range of environmental conditions, such as droughts or varying concentrations of atmospheric pollutants, in order to investigate their influence on the overall net exchange.

A no-key-exchange secure image sharing scheme based on Shamir's three-pass cryptography protocol and the multiple-parameter fractional Fourier transform.

PubMed

Lang, Jun

2012-01-30

In this paper, we propose a novel secure image sharing scheme based on Shamir's three-pass protocol and the multiple-parameter fractional Fourier transform (MPFRFT), which can safely exchange information with no advance distribution of either secret keys or public keys between users. The image is encrypted directly by the MPFRFT spectrum without the use of phase keys, and information can be shared by transmitting the encrypted image (or message) three times between users. Numerical simulation results are given to verify the performance of the proposed algorithm.

Algorithms for Lightweight Key Exchange.

PubMed

Alvarez, Rafael; Caballero-Gil, Cándido; Santonja, Juan; Zamora, Antonio

2017-06-27

Public-key cryptography is too slow for general purpose encryption, with most applications limiting its use as much as possible. Some secure protocols, especially those that enable forward secrecy, make a much heavier use of public-key cryptography, increasing the demand for lightweight cryptosystems that can be implemented in low powered or mobile devices. This performance requirements are even more significant in critical infrastructure and emergency scenarios where peer-to-peer networks are deployed for increased availability and resiliency. We benchmark several public-key key-exchange algorithms, determining those that are better for the requirements of critical infrastructure and emergency applications and propose a security framework based on these algorithms and study its application to decentralized node or sensor networks.

Averaged 30 year climate change projections mask opportunities for species establishment

USGS Publications Warehouse

Serra-Diaz, Josep M.; Franklin, Janet; Sweet, Lynn C.; McCullough, Ian M.; Syphard, Alexandra D.; Regan, Helen M.; Flint, Lorraine E.; Flint, Alan L.; Dingman, John; Moritz, Max A.; Redmond, Kelly T.; Hannah, Lee; Davis, Frank W.

2016-01-01

Survival of early life stages is key for population expansion into new locations and for persistence of current populations (Grubb 1977, Harper 1977). Relative to adults, these early life stages are very sensitive to climate fl uctuations (Ropert-Coudert et al. 2015), which often drive episodic or ‘event-limited’ regeneration (e.g. pulses) in long-lived plant species (Jackson et al. 2009). Th us, it is diffi cult to mechanistically associate 30-yr climate norms to dynamic processes involved in species range shifts (e.g. seedling survival). What are the consequences of temporal aggregation for estimating areas of potential establishment? We modeled seedling survival for three widespread tree species in California, USA ( Quercus douglasii, Q. kelloggii , Pinus sabiniana ) by coupling a large-scale, multi-year common garden experiment to high-resolution downscaled grids of climatic water defi cit and air temperature (Flint and Flint 2012, Supplementary material Appendix 1). We projected seedling survival for nine climate change projections in two mountain landscapes spanning wide elevation and moisture gradients. We compared areas with windows of opportunity for seedling survival – defi ned as three consecutive years of seedling survival in our species, a period selected based on studies of tree niche ontogeny (Supplementary material Appendix 1) – to areas of 30-yr averaged estimates of seedling survival. We found that temporal aggregation greatly underestimated the potential for species establishment (e.g. seedling survival) under climate change scenarios.

City of Fresno peer exchange on bus rapid transit : a TPCB peer exchange

DOT National Transportation Integrated Search

2013-09-11

This report highlights key recommendations and best practices identified at the peer exchange on Bus Rapid Transit (BRT), held on May 21 and May 22, 2013, in Fresno, California. This event was sponsored by the Transportation Planning Capacity Buildin...

Password-only authenticated three-party key exchange with provable security in the standard model.

PubMed

Nam, Junghyun; Choo, Kim-Kwang Raymond; Kim, Junghwan; Kang, Hyun-Kyu; Kim, Jinsoo; Paik, Juryon; Won, Dongho

2014-01-01

Protocols for password-only authenticated key exchange (PAKE) in the three-party setting allow two clients registered with the same authentication server to derive a common secret key from their individual password shared with the server. Existing three-party PAKE protocols were proven secure under the assumption of the existence of random oracles or in a model that does not consider insider attacks. Therefore, these protocols may turn out to be insecure when the random oracle is instantiated with a particular hash function or an insider attack is mounted against the partner client. The contribution of this paper is to present the first three-party PAKE protocol whose security is proven without any idealized assumptions in a model that captures insider attacks. The proof model we use is a variant of the indistinguishability-based model of Bellare, Pointcheval, and Rogaway (2000), which is one of the most widely accepted models for security analysis of password-based key exchange protocols. We demonstrated that our protocol achieves not only the typical indistinguishability-based security of session keys but also the password security against undetectable online dictionary attacks.

Three-pass protocol scheme for bitmap image security by using vernam cipher algorithm

NASA Astrophysics Data System (ADS)

Rachmawati, D.; Budiman, M. A.; Aulya, L.

2018-02-01

Confidentiality, integrity, and efficiency are the crucial aspects of data security. Among the other digital data, image data is too prone to abuse of operation like duplication, modification, etc. There are some data security techniques, one of them is cryptography. The security of Vernam Cipher cryptography algorithm is very dependent on the key exchange process. If the key is leaked, security of this algorithm will collapse. Therefore, a method that minimizes key leakage during the exchange of messages is required. The method which is used, is known as Three-Pass Protocol. This protocol enables message delivery process without the key exchange. Therefore, the sending messages process can reach the receiver safely without fear of key leakage. The system is built by using Java programming language. The materials which are used for system testing are image in size 200×200 pixel, 300×300 pixel, 500×500 pixel, 800×800 pixel and 1000×1000 pixel. The result of experiments showed that Vernam Cipher algorithm in Three-Pass Protocol scheme could restore the original image.

State politics and the creation of health insurance exchanges.

PubMed

Jones, David K; Greer, Scott L

2013-08-01

Health insurance exchanges are a key component of the Affordable Care Act. Each exchange faces the challenge of minimizing friction with existing policies, coordinating churn between programs, and maximizing take-up. State-run exchanges would likely be better positioned to address these issues than a federally run exchange, yet only one third of states chose this path. Policymakers must ensure that their exchange-whether state or federally run-succeeds. Whether this happens will greatly depend on the political dynamics in each state.

Boxing Clever: Using Shoeboxes to Support Home-School Knowledge Exchange

ERIC Educational Resources Information Center

Greenhough, Pamela; Scanlan, Mary; Feiler, Anthony; Johnson, David; Yee, Wan Ching; Andrews, Jane; Price, Alison; Smithson, Maggie; Hughes, Martin

2005-01-01

A key tenet of the Home-School Knowledge Exchange Project is that children's learning will be enhanced if the knowledge and experience that are to be found both at home and in school can be brought together. In this paper we explore ways of connecting home and school to support literacy learning at Key Stage 1, focusing on the home-to-school…

Algorithms for Lightweight Key Exchange †

PubMed Central

Santonja, Juan; Zamora, Antonio

2017-01-01

Public-key cryptography is too slow for general purpose encryption, with most applications limiting its use as much as possible. Some secure protocols, especially those that enable forward secrecy, make a much heavier use of public-key cryptography, increasing the demand for lightweight cryptosystems that can be implemented in low powered or mobile devices. This performance requirements are even more significant in critical infrastructure and emergency scenarios where peer-to-peer networks are deployed for increased availability and resiliency. We benchmark several public-key key-exchange algorithms, determining those that are better for the requirements of critical infrastructure and emergency applications and propose a security framework based on these algorithms and study its application to decentralized node or sensor networks. PMID:28654006

North Central Texas Council of Governments peer exchange on bicycle and pedestrian count programs : a TPCB peer exchange

DOT National Transportation Integrated Search

2013-05-29

This report highlights key recommendations and best practices identified at the peer exchange on bicycle and pedestrian count programs, held on May 29 and May 30, 2013 in Arlington, Texas. The North Central Texas Council of Governments (NCTCOG) reque...

Schools (Students) Exchanging CAD/CAM Files over the Internet.

ERIC Educational Resources Information Center

Mahoney, Gary S.; Smallwood, James E.

This document discusses how students and schools can benefit from exchanging computer-aided design/computer-aided manufacturing (CAD/CAM) files over the Internet, explains how files are exchanged, and examines the problem of selected hardware/software incompatibility. Key terms associated with information search services are defined, and several…

Secure password-based authenticated key exchange for web services

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, Fang; Meder, Samuel; Chevassut, Olivier

This paper discusses an implementation of an authenticated key-exchange method rendered on message primitives defined in the WS-Trust and WS-SecureConversation specifications. This IEEE-specified cryptographic method (AuthA) is proven-secure for password-based authentication and key exchange, while the WS-Trust and WS-Secure Conversation are emerging Web Services Security specifications that extend the WS-Security specification. A prototype of the presented protocol is integrated in the WSRF-compliant Globus Toolkit V4. Further hardening of the implementation is expected to result in a version that will be shipped with future Globus Toolkit releases. This could help to address the current unavailability of decent shared-secret-based authentication options inmore » the Web Services and Grid world. Future work will be to integrate One-Time-Password (OTP) features in the authentication protocol.« less

Multiple image encryption scheme based on pixel exchange operation and vector decomposition

NASA Astrophysics Data System (ADS)

Xiong, Y.; Quan, C.; Tay, C. J.

2018-02-01

We propose a new multiple image encryption scheme based on a pixel exchange operation and a basic vector decomposition in Fourier domain. In this algorithm, original images are imported via a pixel exchange operator, from which scrambled images and pixel position matrices are obtained. Scrambled images encrypted into phase information are imported using the proposed algorithm and phase keys are obtained from the difference between scrambled images and synthesized vectors in a charge-coupled device (CCD) plane. The final synthesized vector is used as an input in a random phase encoding (DRPE) scheme. In the proposed encryption scheme, pixel position matrices and phase keys serve as additional private keys to enhance the security of the cryptosystem which is based on a 4-f system. Numerical simulations are presented to demonstrate the feasibility and robustness of the proposed encryption scheme.

Scalable Authenticated Tree Based Group Key Exchange for Ad-Hoc Groups

NASA Astrophysics Data System (ADS)

Desmedt, Yvo; Lange, Tanja; Burmester, Mike

Task-specific groups are often formed in an ad-hoc manner within large corporate structures, such as companies. Take the following typical scenario: A director decides to set up a task force group for some specific project. An order is passed down the hierarchy where it finally reaches a manager who selects some employees to form the group. The members should communicate in a secure way and for efficiency, a symmetric encryption system is chosen. To establish a joint secret key for the group, a group key exchange (GKE) protocol is used. We show how to use an existing Public Key Infrastructure (PKI) to achieve authenticated GKE by modifying the protocol and particularly by including signatures.

Use of SAR in Regional Methane Exchange Studies

NASA Technical Reports Server (NTRS)

Morrissey, L. A.; Livingston, G. P.; Durden, S. L.

1994-01-01

Significant sources of uncertainty in global trace gas budgets are due to lack of knowledge concerning the areal and temporal extent of source and sink areas. Synthetic aperture radar (SAR) is particularly suited to studies of northern ecosystems because of its all-weather operating capability which enables the acquisition of seasonal data. As key controls on methane exchange, the ability to differentiate major vegetation communities, inundation, and leaf area index (LAI) with satellite and airborne SAR data would increase the accuracy and precision of regional and seasonal estimates of methane exchange. The utility of SAR data for monitoring key controls on methane emissions from Arctic and boreal ecosystems is examined.

Generalized Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchange system using arbitrary resistors.

PubMed

Vadai, Gergely; Mingesz, Robert; Gingl, Zoltan

2015-09-03

The Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchange system has been introduced as a simple, very low cost and efficient classical physical alternative to quantum key distribution systems. The ideal system uses only a few electronic components-identical resistor pairs, switches and interconnecting wires-in order to guarantee perfectly protected data transmission. We show that a generalized KLJN system can provide unconditional security even if it is used with significantly less limitations. The more universal conditions ease practical realizations considerably and support more robust protection against attacks. Our theoretical results are confirmed by numerical simulations.

State Politics and the Creation of Health Insurance Exchanges

PubMed Central

Greer, Scott L.

2013-01-01

Health insurance exchanges are a key component of the Affordable Care Act. Each exchange faces the challenge of minimizing friction with existing policies, coordinating churn between programs, and maximizing take-up. State-run exchanges would likely be better positioned to address these issues than a federally run exchange, yet only one third of states chose this path. Policymakers must ensure that their exchange—whether state or federally run—succeeds. Whether this happens will greatly depend on the political dynamics in each state. PMID:23763405

Effects of Early Leader-Member Exchange Perceptions on Academic Outcomes

ERIC Educational Resources Information Center

Jacques, Paul H.; Garger, John; Thomas, Michael; Vracheva, Veselina

2012-01-01

This study tested a series of hypotheses linking college support and quality of student-instructor relations with outcomes including student efficacy, social connectedness with peers, expectancies and academic performance. Early quality of exchanges with the instructor using Leader-Member Exchange theory was found to be a key indicator of academic…

Understanding the "Other Side": Intercultural learning in a Spanish-English E-Mail Exchange.

ERIC Educational Resources Information Center

O'Dowd, Robert

2003-01-01

Reviews recent research on intercultural learning and reports on a yearlong e-mail exchange between Spanish and English second year university students. Identifies key characteristics of e-mail exchanges that helped to develop learners' intercultural communicative competence. Outlines elements of e-mail messages that may enable students to develop…

The Shock and Vibration Digest. Volume 14, Number 7

DTIC Science & Technology

1982-07-01

Yang, ed., pp 93-107, 13 figs, 4 refs Key Words: Tube arrays. Heat exchangers . Wind tunnel testing . Critical speeds. Fluid-induced excitation...the Eighties," Proc. Const. Indus. Res. Inform. Assoc. Conf., Lon- don, UK (Nov 1980). 38 BOOK REVIEWS FLOW-INDUCED HEAT EXCHANGER TUBE...1980 Heat exchanger problems caused by flow-induced vibration are of concern to designers and operators of heat exchangers . Flow-induced vibration

Password-Only Authenticated Three-Party Key Exchange with Provable Security in the Standard Model

PubMed Central

Nam, Junghyun; Kim, Junghwan; Kang, Hyun-Kyu; Kim, Jinsoo; Paik, Juryon

2014-01-01

Protocols for password-only authenticated key exchange (PAKE) in the three-party setting allow two clients registered with the same authentication server to derive a common secret key from their individual password shared with the server. Existing three-party PAKE protocols were proven secure under the assumption of the existence of random oracles or in a model that does not consider insider attacks. Therefore, these protocols may turn out to be insecure when the random oracle is instantiated with a particular hash function or an insider attack is mounted against the partner client. The contribution of this paper is to present the first three-party PAKE protocol whose security is proven without any idealized assumptions in a model that captures insider attacks. The proof model we use is a variant of the indistinguishability-based model of Bellare, Pointcheval, and Rogaway (2000), which is one of the most widely accepted models for security analysis of password-based key exchange protocols. We demonstrated that our protocol achieves not only the typical indistinguishability-based security of session keys but also the password security against undetectable online dictionary attacks. PMID:24977229

NJDOT research peer exchange, October 2001 : information package.

DOT National Transportation Integrated Search

2001-10-01

Summary of the Peer Exchange Take Home Ideas: : Be proactive in regularly meeting with key stakeholder managers to identify their : strategic needs in moving their program responsibilities forward. : Incorporate discussion of strategic ...

Jak2 and Ca2+/calmodulin are key intermediates for bradykinin B2 receptor-mediated activation of Na+/H+ exchange in KNRK and CHO cells.

PubMed

Lefler, David; Mukhin, Yurii V; Pettus, Tobiah; Leeb-Lundberg, L M Fredrik; Garnovskaya, Maria N; Raymond, John R

2003-04-01

Na(+)/H(+) exchangers are ubiquitous in mammalian cells, carrying out key functions, such as cell volume defense, acid-base homeostasis, and regulation of the cytoskeleton. We used two screening technologies (FLIPR and microphysiometry) to characterize the signal transduction pathway used by the bradykinin B(2) receptor to activate Na(+)/H(+) exchange in two cell lines, KNRK and CHO. In both cell types, B(2) receptor activation resulted in rapid increases in the rate of proton extrusion that were sodium-dependent and could be blocked by the Na(+)/H(+) exchange inhibitors EIPA and MIA or by replacing extracellular sodium with TMA. Activation of Na(+)/H(+) exchange by bradykinin was concentration-dependent and could be blocked by the selective B(2) receptor antagonist HOE140, but not by the B(1) receptor antagonist des-Arg10-HOE140. Inhibitors of Jak2 tyrosine kinase (genistein and AG490) and of CAM (W-7 and calmidazolium) attenuated bradykinin-induced activation of Na(+)/H(+) exchange. Bradykinin induced formation of a complex between CAM and Jak2, supporting a regulatory role for Jak2 and CAM in the activation of Na(+)/H(+) exchange in KNRK and CHO cells. We propose that this pathway (B(2) receptor --> Jak2 --> CAM --> Na(+)/H(+) exchanger) is a fundamental regulator of Na(+)/H(+) exchange activity.

Statewide and Metropolitan Transportation Planning Processes : a TPCB Peer Exchange

DOT National Transportation Integrated Search

2016-04-20

This report highlights key recommendations and noteworthy practices identified at Statewide and Metropolitan Transportation Planning Processes Peer Exchange held on September 9-10, 2015 in Shepherdstown, West Virginia. This event was sponsored ...

Establishing and integrating performance measures : a TPCB peer exchange

DOT National Transportation Integrated Search

2015-08-31

This report highlights key recommendations and noteworthy practices identified at Establishing and Integrating Performance Measures Peer Exchange held on April 27-28, 2015 in Dimondale, Michigan and via video teleconference. This event was spon...

Tag Content Access Control with Identity-based Key Exchange

NASA Astrophysics Data System (ADS)

Yan, Liang; Rong, Chunming

2010-09-01

Radio Frequency Identification (RFID) technology that used to identify objects and users has been applied to many applications such retail and supply chain recently. How to prevent tag content from unauthorized readout is a core problem of RFID privacy issues. Hash-lock access control protocol can make tag to release its content only to reader who knows the secret key shared between them. However, in order to get this shared secret key required by this protocol, reader needs to communicate with a back end database. In this paper, we propose to use identity-based secret key exchange approach to generate the secret key required for hash-lock access control protocol. With this approach, not only back end database connection is not needed anymore, but also tag cloning problem can be eliminated at the same time.

A Collaborative Approach to Defining the Usefulness of Impact: Lessons from a Knowledge Exchange Project Involving Academics and Social Work Practitioners

ERIC Educational Resources Information Center

Wilkinson, Heather; Gallagher, Michael; Smith, Mark

2012-01-01

This paper reports on a knowledge exchange project involving academics and practitioners in six local authority social work departments. It contributes to recent debates about the coproduction of knowledge, presenting findings in three key areas: the importance of relationships for knowledge exchange; "what works" for practitioners…

Automated secured cost effective key refreshing technique to enhance WiMAX privacy key management

NASA Astrophysics Data System (ADS)

Sridevi, B.; Sivaranjani, S.; Rajaram, S.

2013-01-01

In all walks of life the way of communication is transformed by the rapid growth of wireless communication and its pervasive use. A wireless network which is fixed and richer in bandwidth is specified as IEEE 802.16, promoted and launched by an industrial forum is termed as Worldwide Interoperability for Microwave Access (WiMAX). This technology enables seamless delivery of wireless broadband service for fixed and/or mobile users. The obscurity is the long delay which occurs during the handoff management in every network. Mobile WiMAX employs an authenticated key management protocol as a part of handoff management in which the Base Station (BS) controls the distribution of keying material to the Mobile Station (MS). The protocol employed is Privacy Key Management Version 2- Extensible Authentication Protocol (PKMV2-EAP) which is responsible for the normal and periodical authorization of MSs, reauthorization as well as key refreshing. Authorization key (AK) and Traffic Encryption key (TEK) plays a vital role in key exchange. When the lifetime of key expires, MS has to request for a new key to BS which in turn leads to repetition of authorization, authentication as well as key exchange. To avoid service interruption during reauthorization , two active keys are transmitted at the same time by BS to MS. The consequences of existing work are hefty amount of bandwidth utilization, time consumption and large storage. It is also endured by Man in the Middle attack and Impersonation due to lack of security in key exchange. This paper designs an automatic mutual refreshing of keys to minimize bandwidth utilization, key storage and time consumption by proposing Previous key and Iteration based Key Refreshing Function (PKIBKRF). By integrating PKIBKRF in key generation, the simulation results indicate that 21.8% of the bandwidth and storage of keys are reduced and PKMV2 mutual authentication time is reduced by 66.67%. The proposed work is simulated with Qualnet model and backed by MATLAB for processing and MYSQL for storing keys.

Physical Unclonable Function Hardware Keys Utilizing Kirchhoff-Law Secure Key Exchange and Noise-Based Logic

NASA Astrophysics Data System (ADS)

Kish, Laszlo B.; Kwan, Chiman

Weak unclonable function (PUF) encryption key means that the manufacturer of the hardware can clone the key but not anybody else. Strong unclonable function (PUF) encryption key means that even the manufacturer of the hardware is unable to clone the key. In this paper, first we introduce an "ultra" strong PUF with intrinsic dynamical randomness, which is not only unclonable but also gets renewed to an independent key (with fresh randomness) during each use via the unconditionally secure key exchange. The solution utilizes the Kirchhoff-law-Johnson-noise (KLJN) method for dynamical key renewal and a one-time-pad secure key for the challenge/response process. The secure key is stored in a flash memory on the chip to provide tamper-resistance and nonvolatile storage with zero power requirements in standby mode. Simplified PUF keys are shown: a strong PUF utilizing KLJN protocol during the first run and noise-based logic (NBL) hyperspace vector string verification method for the challenge/response during the rest of its life or until it is re-initialized. Finally, the simplest PUF utilizes NBL without KLJN thus it can be cloned by the manufacturer but not by anybody else.

Calculation of key reduction for B92 QKD protocol

NASA Astrophysics Data System (ADS)

Mehic, Miralem; Partila, Pavol; Tovarek, Jaromir; Voznak, Miroslav

2015-05-01

It is well known that Quantum Key Distribution (QKD) can be used with the highest level of security for distribution of the secret key, which is further used for symmetrical encryption. B92 is one of the oldest QKD protocols. It uses only two non-orthogonal states, each one coding for one bit-value. It is much faster and simpler when compared to its predecessors, but with the idealized maximum efficiencies of 25% over the quantum channel. B92 consists of several phases in which initial key is significantly reduced: secret key exchange, extraction of the raw key (sifting), error rate estimation, key reconciliation and privacy amplification. QKD communication is performed over two channels: the quantum channel and the classical public channel. In order to prevent a man-in-the-middle attack and modification of messages on the public channel, authentication of exchanged values must be performed. We used Wegman-Carter authentication because it describes an upper bound for needed symmetric authentication key. We explained the reduction of the initial key in each of QKD phases.

Focus groups to explore healthcare professionals' experiences of care coordination: towards a theoretical framework for the study of care coordination.

PubMed

Van Houdt, Sabine; Sermeus, Walter; Vanhaecht, Kris; De Lepeleire, Jan

2014-12-24

Strategies to improve care coordination between primary and hospital care do not always have the desired results. This is partly due to incomplete understanding of the key concepts of care coordination. An in-depth analysis of existing theoretical frameworks for the study of care coordination identified 14 interrelated key concepts. In another study, these 14 key concepts were further explored in patients' experiences. Additionally, "patient characteristics" was identified as a new key concept in patients' experiences and the previously identified key concept "quality of relationship" between healthcare professionals was extended to "quality of relationship" with the patient. Together, these 15 interrelated key concepts resulted in a new theoretical framework. The present study aimed at improving our understanding of the 15 previously identified key concepts and to explore potentially previous unidentified key concepts and the links between these by exploring how healthcare professionals experience care coordination. A qualitative design was used. Six focus groups were conducted including primary healthcare professionals involved in the care of patients who had breast cancer surgery at three hospitals in Belgium. Data were analyzed using constant comparative analysis. All 15 previously identified key concepts of care coordination were further explored in healthcare professionals' experiences. Links between these 15 concepts were identified, including 9 newly identified links. The concept "external factors" was linked with all 6 concepts relating to (inter)organizational mechanisms; "task characteristics", "structure", "knowledge and information technology", "administrative operational processes", "cultural factors" and "need for coordination". Five of these concepts related to 3 concepts of relational coordination; "roles", "quality of relationship" and "exchange of information". The concept of "task characteristics" was only linked with "roles" and "exchange of information". The concept "patient characteristics" related with the concepts "need for coordination" and "patient outcome". Outcome was influenced by "roles", "quality of relationship" and "exchange of information". External factors and the (inter)organizational mechanism should enhance "roles" and "quality of relationship" between healthcare professionals and with the patient as well as "exchange of information", and setting and sharing of common "goals" to improve care coordination and quality of care.

North Carolina DOT peer exchange on performance management

DOT National Transportation Integrated Search

2014-09-01

This report highlights key recommendations and best practices identified at the peer exchange on Transportation Asset Management Plans (TAMP), held on February 5 and 6, 2014, in Columbia, South Carolina. This event was sponsored by the Transportation...

Cross-modal project prioritization : a TPCB peer exchange.

DOT National Transportation Integrated Search

2015-05-01

This report highlights key recommendations and best practices identified at the peer exchange on Cross-Modal Project Prioritization, held on December 16 and 17, 2014, in Raleigh, North Carolina. This event was sponsored by the Transportation Planning...

Cálculo del esfuerzo ideal de metales nobles mediante primeros principios en la dirección <100>

NASA Astrophysics Data System (ADS)

Bautista-Hernández, A.; López-Fuentes, M.; Pacheco-Espejel, V.; Rivas-Silva, J. F.

2005-04-01

We present calculations of the ideal strength on the < 100 > direction for noble metals (Cu, Ag and Au), by means of first principles calculations. First, we obtain the structural parameters (cell parameters, bulk modulus) for each studied metal. We deform on the < 100 > direction calculating the total energy and the stress tensor through the Hellman-Feynman theorem, by the relaxation of the unit cell in the perpendicular directions to the deformation one. The calculated cell constants differ 1.3 % from experimental data. The maximum ideal strength are 29.6, 17 and 19 GPa for Cu, Ag and Au respectively. Meanwhile, the calculated elastic modulus are 106 (Cu), 71 (Ag), and 45 GPa (Au) and are in agreement with the experimental values for polycrystalline samples. The values of maximum strength are explained by the optimum volume values due to the atomic radius size for each element.

Summary of Research 1998, Department of Mechanical Engineering.

DTIC Science & Technology

1999-08-01

thermoacoustic behavior in strong zero-mean oscillatory flows with potential application to the design of heat exchangers in thermoacoustic engines...important feature in the thermal characterization of microtubes , which are to be used in microheat exchangers . DoD KEY TECHNOLOGY AREA: Modeling and...Simulation KEYWORDS: Laminar Duct Flows, Convection and Conduction Heat Transfer, Axial Conduction, Micro- heat Exchang - ers DEVELOPMENT AND CALIBRATION

CALINX (California Information Exchange): a multi-stakeholder statewide initiative to improve healthcare information flows.

PubMed

Hopkins, D S; Oswald, N; McCaffrey, K; Bressler, S; Davidson, N; Vela, L

2000-01-01

Given the diffusion of responsibilities for gathering and reporting healthcare information in a managed care environment, California stakeholders are taking concrete steps to break the deadlock on data and information flows that has characterized the industry for some time. The California Information Exchange (CALINX) was established to facilitate the implementation of the Health Insurance Portability and Accountability Act (HIPAA) standards in California and to create trust for data exchange between trading partners, without which data exchange still will not occur. Strategic directions are set by the chief executives of key associations and organizations representing purchasers, plans, providers, and consumers. Multi-stakeholder workgroups have produced detailed data guidelines for the HIPAA standards along with rules for exchange of key data sets between trading partners. These rules address frequency, timeliness, and accuracy of data submission. Both the data guidelines and the rules have been tested in live demonstration projects, and the results of these projects have been reported to substantiate the business case for implementation. Further incentives are being built into contracts between purchasers and plans, and between plans and providers. CALINX is currently promoting widespread adoption of the data guidelines and rules for exchange with all members of the industry.

I-10 Corridor Coalition : a TPCB peer exchange

DOT National Transportation Integrated Search

2016-11-01

This report highlights key outcomes identified at the I-10 Corridor Coalition Peer Exchange held on June 2, 2016 in Phoenix, Arizona. This event was sponsored by the Transportation Planning Capacity Building (TPCB) Peer Program, which is jointl...

Transit-Oriented Development (TOD) in Southern Nevada : A TPCB Peer Exchange

DOT National Transportation Integrated Search

2016-07-01

This report highlights key recommendations and noteworthy practices identified at Transit-Oriented Development in Southern Nevada Peer Exchange held on December 2-3, 2015 in Las Vegas, Nevada. This event was sponsored by the Transportation Plan...

Rethinking I-94: Minnesota DOT: A TPCB Peer Exchange

DOT National Transportation Integrated Search

2017-12-01

This report highlights key recommendations and noteworthy practices identified at Rethinking I-94: MnDOT Peer Exchange held on August 15-16, 2017 in St. Paul, Minnesota. This event was sponsored by the Transportation Planning Capacity Building ...

Insurance exchanges under health reform: six design issues for the states.

PubMed

Kingsdale, Jon; Bertko, John

2010-06-01

The Patient Protection and Affordable Care Act depends on new, state-based exchanges to make health insurance readily available to certain segments of the population. One such segment is the lower-income uninsured, who can qualify for subsidized coverage only through an exchange. Other segments are unsubsidized individuals and small employers, who may choose to buy coverage inside or outside of an exchange. Although the law provides some guidance in structuring these new exchanges, it leaves many key decisions to the states. Successfully implementing exchanges will require public-private partnerships, expertise in insurance operations and marketing, and a series of strategic decisions. We review the half-dozen most important design issues.

Probabilistic estimation of residential air exchange rates for population-based human exposure modeling

EPA Science Inventory

Residential air exchange rates (AERs) are a key determinant in the infiltration of ambient air pollution indoors. Population-based human exposure models using probabilistic approaches to estimate personal exposure to air pollutants have relied on input distributions from AER meas...

Nursing staff and their team: Impact on intention to leave.

PubMed

Trybou, J; Malfait, S; Gemmel, P; Clays, E

2015-12-01

The aim was to examine the relationship between the quality of team-member exchange experienced by nursing staff and their intention to leave. Job satisfaction and affective organizational commitment are considered as mediators. While the shortage of nurses is a management and policy priority, few studies have studied the relationships between nursing staff and their team, key organizational attitudes, and intentions to leave the organization. A questionnaire was administered to 217 registered nurses and nurse assistants in Belgium. Data were collected in 2012. To analyse the data, descriptive statistics, correlation, regression and path analyses were conducted. Team-member exchange has a positive impact on nursing staff satisfaction and affective commitment. Job satisfaction and affective organizational commitment fully mediated the impact of team-member exchange on nursing staff's intention to leave. This study illustrates the potential benefits of the positive influence of team-member exchange on key organizational attitudes of nursing staff, and the negative influence on intention to leave through affective commitment and job satisfaction. © 2015 International Council of Nurses.

Microscopic theory of cation exchange in CdSe nanocrystals.

PubMed

Ott, Florian D; Spiegel, Leo L; Norris, David J; Erwin, Steven C

2014-10-10

Although poorly understood, cation-exchange reactions are increasingly used to dope or transform colloidal semiconductor nanocrystals (quantum dots). We use density-functional theory and kinetic Monte Carlo simulations to develop a microscopic theory that explains structural, optical, and electronic changes observed experimentally in Ag-cation-exchanged CdSe nanocrystals. We find that Coulomb interactions, both between ionized impurities and with the polarized nanocrystal surface, play a key role in cation exchange. Our theory also resolves several experimental puzzles related to photoluminescence and electrical behavior in CdSe nanocrystals doped with Ag.

Exploring knowledge exchange at the research-policy-practice interface in children's behavioral health services.

PubMed

Leslie, Laurel K; Maciolek, Susan; Biebel, Kathleen; Debordes-Jackson, Gifty; Nicholson, Joanne

2014-11-01

This case study explored core components of knowledge exchange among researchers, policymakers, and practitioners within the context of the Rosie D. versus Romney class action lawsuit in Massachusetts and the development and implementation of its remedial plan. We identified three distinct, sequential knowledge exchange episodes with different purposes, stakeholders, and knowledge exchanged, as decision-making moved from Federal Medicaid policy to state Medicaid program standards and to community-level practice. The knowledge exchanged included research regarding Wraparound, a key component of the remedial plan, as well as contextual information critical for implementation (e.g., Federal Medicaid policy, managed care requirements, community organizations' characteristics).

Regional cooperation and performance-based planning and programming in Indiana : a regional models of cooperation peer exchange summary report

DOT National Transportation Integrated Search

2016-05-01

This report highlights key themes identified at the Regional Cooperation and Performance-Based Planning and Programming in Indiana Peer Exchange held on May 25, 2016 in Indianapolis, Indiana. The Regional Models of Cooperation Initiative, which...

Regional cooperation and environmental justice in transportation planning in Ohio : a regional models of cooperation peer exchange summary report

DOT National Transportation Integrated Search

2016-06-07

This report highlights key themes identified at the Regional Cooperation and Environmental Justice in Transportation Planning in Ohio Peer Exchange held on December 15, 2015 in Columbus, Ohio. The Regional Models of Cooperation Initiative, whic...

Reflections on Cyberspace as the New "Wired World of Education"

ERIC Educational Resources Information Center

Ward, Andrew; Prosser, Brian T.

2011-01-01

Developments in Information Technologies (ITs) like the Internet have transformed information exchange. Moreover, since information exchange and analysis are key aspects of the learning experience, these developments have had an important impact on education. Within this context, the important question concerns the sort of educational…

Cooperative freight mobility planning in the greater Charlotte region : a regional models of cooperation peer exchange summary report

DOT National Transportation Integrated Search

2016-04-01

This report highlights key themes identified at the Planes, Trains, & Semis: Keeping a Dynamic Economy on the Move: Greater Charlotte Regional Freight Mobility Plan Peer Exchange held on November 13, 2015 in Charlotte, North Carolina. This even...

Regional cooperation and bike/ped and transit connections : a regional models of cooperation peer exchange summary report

DOT National Transportation Integrated Search

2016-10-01

This report summarizes the presentations, key themes, and recommendations identified at a Regional Models of Cooperation peer exchange on October 24, 2016 in Salt Lake City, Utah. The Utah Transit Authority hosted peers from the Los Angeles Metropoli...

Novel image compression-encryption hybrid algorithm based on key-controlled measurement matrix in compressive sensing

NASA Astrophysics Data System (ADS)

Zhou, Nanrun; Zhang, Aidi; Zheng, Fen; Gong, Lihua

2014-10-01

The existing ways to encrypt images based on compressive sensing usually treat the whole measurement matrix as the key, which renders the key too large to distribute and memorize or store. To solve this problem, a new image compression-encryption hybrid algorithm is proposed to realize compression and encryption simultaneously, where the key is easily distributed, stored or memorized. The input image is divided into 4 blocks to compress and encrypt, then the pixels of the two adjacent blocks are exchanged randomly by random matrices. The measurement matrices in compressive sensing are constructed by utilizing the circulant matrices and controlling the original row vectors of the circulant matrices with logistic map. And the random matrices used in random pixel exchanging are bound with the measurement matrices. Simulation results verify the effectiveness, security of the proposed algorithm and the acceptable compression performance.

Substitution effects in a generalized token economy with pigeons.

PubMed

Andrade, Leonardo F; Hackenberg, Timothy D

2017-01-01

Pigeons made repeated choices between earning and exchanging reinforcer-specific tokens (green tokens exchangeable for food, red tokens exchangeable for water) and reinforcer-general tokens (white tokens exchangeable for food or water) in a closed token economy. Food and green food tokens could be earned on one panel; water and red water tokens could be earned on a second panel; white generalized tokens could be earned on either panel. Responses on one key produced tokens according to a fixed-ratio schedule, whereas responses on a second key produced exchange periods, during which all previously earned tokens could be exchanged for the appropriate commodity. Most conditions were conducted in a closed economy, and pigeons distributed their token allocation in ways that permitted food and water consumption. When the price of all tokens was equal and low, most pigeons preferred the generalized tokens. When token-production prices were manipulated, pigeons reduced production of the tokens that increased in price while increasing production of the generalized tokens that remained at a fixed price. The latter is consistent with a substitution effect: Generalized tokens increased and were exchanged for the more expensive reinforcer. When food and water were made freely available outside the session, token production and exchange was sharply reduced but was not eliminated, even in conditions when it no longer produced tokens. The results join with other recent data in showing sustained generalized functions of token reinforcers, and demonstrate the utility of token-economic methods for assessing demand for and substitution among multiple commodities in a laboratory context. © 2016 Society for the Experimental Analysis of Behavior.

SUBSTITUTION EFFECTS IN A GENERALIZED TOKEN ECONOMY WITH PIGEONS

PubMed Central

Andrade, Leonardo F.; Hackenberg, Timothy D.

2016-01-01

Pigeons made repeated choices between earning and exchanging reinforcer-specific tokens (green tokens exchangeable for food, red tokens exchangeable for water) and reinforcer-general tokens (white tokens exchangeable for food or water) in a closed token economy. Food and green food tokens could be earned on one panel; water and red water tokens could be earned on a second panel; white generalized tokens could be earned on either panel. Responses on one key produced tokens according to a fixed-ratio schedule, whereas responses on a second key produced exchange periods, during which all previously earned tokens could be exchanged for the appropriate commodity. Most conditions were conducted in a closed economy, and pigeons distributed their token allocation in ways that permitted food and water consumption. When the price of all tokens was equal and low, most pigeons preferred the generalized tokens. When token-production prices were manipulated, pigeons reduced production of the tokens that increased in price while increasing production of the generalized tokens that remained at a fixed price. The latter is consistent with a substitution effect: Generalized tokens increased and were exchanged for the more expensive reinforcer. When food and water were made freely available outside the session, token production and exchange was sharply reduced but was not eliminated, even in conditions when it no longer produced tokens. The results join with other recent data in showing sustained generalized functions of token reinforcers, and demonstrate the utility of token-economic methods for assessing demand for and substitution among multiple commodities in a laboratory context. PMID:28000221

Chaotic maps and biometrics-based anonymous three-party authenticated key exchange protocol without using passwords

NASA Astrophysics Data System (ADS)

Xie, Qi; Hu, Bin; Chen, Ke-Fei; Liu, Wen-Hao; Tan, Xiao

2015-11-01

In three-party password authenticated key exchange (AKE) protocol, since two users use their passwords to establish a secure session key over an insecure communication channel with the help of the trusted server, such a protocol may suffer the password guessing attacks and the server has to maintain the password table. To eliminate the shortages of password-based AKE protocol, very recently, according to chaotic maps, Lee et al. [2015 Nonlinear Dyn. 79 2485] proposed a first three-party-authenticated key exchange scheme without using passwords, and claimed its security by providing a well-organized BAN logic test. Unfortunately, their protocol cannot resist impersonation attack, which is demonstrated in the present paper. To overcome their security weakness, by using chaotic maps, we propose a biometrics-based anonymous three-party AKE protocol with the same advantages. Further, we use the pi calculus-based formal verification tool ProVerif to show that our AKE protocol achieves authentication, security and anonymity, and an acceptable efficiency. Project supported by the Natural Science Foundation of Zhejiang Province, China (Grant No. LZ12F02005), the Major State Basic Research Development Program of China (Grant No. 2013CB834205), and the National Natural Science Foundation of China (Grant No. 61070153).

Freight planning and regional cooperation in the Piedmont Atlantic megaregion : a regional models of cooperation peer exchange summary report

DOT National Transportation Integrated Search

2017-09-08

This report highlights key themes identified at the Freight Planning and Regional Cooperation in the Piedmont Atlantic Megaregion Peer Exchange held on January 31, 2017 and February 1, 2017 in Atlanta, Georgia. The Regional Models of Cooperatio...

77 FR 34434 - Self-Regulatory Organizations; BATS Exchange, Inc.; Notice of Filing and Immediate Effectiveness...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-11

... introducing broker proprietary accounts along with key personnel to Apex Clearing (the ``Transferring Accounts... Member, will provide the clearing and execution services currently provided to the Transferring Accounts... the Transferring Accounts, Apex Clearing has requested that the Exchange temporarily suspend its new...

CO2 AND O3 ALTER PHOTOSYNTHESIS AND WATER VAPOR EXCHANGE FOR PINUS PONDEROSA NEEDLES

EPA Science Inventory

1. Effects of CO2 and O3 were determined for a key component of ecosystem carbon and water cycling: needle gas exchange (photosynthesis, conductance, transpiration and water use efficiency). The measurements were made on Pinus ponderosa seedlings grown in outdoor, sunlit, mesoc...

Math Exchanges: Guiding Young Mathematicians in Small-Group Meetings

ERIC Educational Resources Information Center

Wedekind, Kassia Omohundro

2011-01-01

Traditionally, small-group math instruction has been used as a format for reaching children who struggle to understand. Math coach Kassia Omohundro Wedekind uses small-group instruction as the centerpiece of her math workshop approach, engaging all students in rigorous "math exchanges." The key characteristics of these mathematical conversations…

A Global Approach to STEM Education: ASTA Science Teachers Exchange--Japan 2015

ERIC Educational Resources Information Center

Teaching Science, 2015

2015-01-01

The new Australian Curriculum includes among its three cross-curriculum priorities a focus on Asia and Australia's engagement with Asia. The Australian Science Teachers Association (ASTA)'s Science Teachers Exchange--JAPAN program provides teachers with direct, personal insight into one of Australia's key Asian neighbours.

Unconditionally Secure Credit/Debit Card Chip Scheme and Physical Unclonable Function

NASA Astrophysics Data System (ADS)

Kish, Laszlo B.; Entesari, Kamran; Granqvist, Claes-Göran; Kwan, Chiman

The statistical-physics-based Kirchhoff-law-Johnson-noise (KLJN) key exchange offers a new and simple unclonable system for credit/debit card chip authentication and payment. The key exchange, the authentication and the communication are unconditionally secure so that neither mathematics- nor statistics-based attacks are able to crack the scheme. The ohmic connection and the short wiring lengths between the chips in the card and the terminal constitute an ideal setting for the KLJN protocol, and even its simplest versions offer unprecedented security and privacy for credit/debit card chips and applications of physical unclonable functions (PUFs).

Perspectives of voltage control for magnetic exchange bias in multiferroic heterostructures

NASA Astrophysics Data System (ADS)

Yang, Q.; Zhou, Z.; Sun, N. X.; Liu, M.

2017-04-01

Exchange bias, as an internal magnetic bias induced by a ferromagnetic-antiferromagnetic exchange coupling, is extremely important in many magnetic applications such as memories, sensors and other devices. Voltage control of exchange bias in multiferroics provides an energy-efficient way to achieve a rapidly 180° deterministic switching of magnetization, which has been considered as a key challenge in realizing next generation of fast, compact and ultra-low power magnetoelectric memories and sensors. Additionally, exchange bias can enhance dynamic magnetoelectric coupling strength in an external-field-free manner. In this paper, we provide a perspective on voltage control of exchange bias in different multiferroic heterostructures. Brief mechanization and related experiments are discussed as well as future trend and challenges that can be overcome by electrically tuning of exchange bias in state-of-the-art magnetoelectric devices.

Carbon charge exchange analysis in the ITER-like wall environment.

PubMed

Menmuir, S; Giroud, C; Biewer, T M; Coffey, I H; Delabie, E; Hawkes, N C; Sertoli, M

2014-11-01

Charge exchange spectroscopy has long been a key diagnostic tool for fusion plasmas and is well developed in devices with Carbon Plasma-Facing Components. Operation with the ITER-like wall at JET has resulted in changes to the spectrum in the region of the Carbon charge exchange line at 529.06 nm and demonstrates the need to revise the core charge exchange analysis for this line. An investigation has been made of this spectral region in different plasma conditions and the revised description of the spectral lines to be included in the analysis is presented.

Scale indicators of social exchange relationships: a comparison of relative content validity.

PubMed

Colquitt, Jason A; Baer, Michael D; Long, David M; Halvorsen-Ganepola, Marie D K

2014-07-01

Although social exchange theory has become one of the most oft-evoked theories in industrial and organizational psychology, there remains no consensus about how to measure its key mechanism: social exchange relationships (Blau, 1964). Drawing on Cropanzano and Byrne's (2000) review of contemporary social exchange theorizing, we examined the content validity of perceived support, exchange quality, affective commitment, trust, and psychological contract fulfillment as indicators of social exchange relationships. We used Hinkin and Tracey's (1999) quantitative approach to content validation, which asks participants to rate the correspondence between scale items and definitions of intended (and unintended) constructs. Our results revealed that some of the most frequently utilized indicators of social exchange relationships--perceived support and exchange quality--were significantly less content valid than rarely used options like affect-based trust. Our results also revealed that 2 direct measures--Bernerth, Armenakis, Feild, Giles, and Walker's (2007) scale and a scale created for this study--were content valid. We discuss the implications of these results for future applications of social exchange theory.

New Hampshire Department of Transportation research peer exchange : increasing the impact : program management strategies and opportunities, September 27 to 29, 2016, Concord, New Hampshire.

DOT National Transportation Integrated Search

2016-09-01

To support the peer exchange focus on improving the visibility and impact of the research : program, the agenda (Appendix A) was structured around five key topic areas presented : below. The NHDOT planning team developed amplifying questions for each...

Improving policy and practice to promote equity and social justice - a qualitative comparative analysis building on key learnings from a twinning exchange between England and the US.

PubMed

Blanchard, Claire; Narle, Ginder; Gibbs, Martin; Ruddock, Charmaine; Grady, Michael; Brookes, Chris; Hopkins, Trevor; Norwood, Jayne

2013-12-01

Community health promotion interventions, targeted at marginalised populations and focusing on addressing the social determinants of health (SDH) to reduce health inequalities and addressing the processes of exclusion, are an important strategy to prevent and control non-communicable diseases (NCDs) and promote the health of underprivileged and under-resourced groups. This article builds on key lessons learnt from a learning exchange between Communities for Health in England and the Racial and Ethnic Approaches to Community Health across the US (REACH US) communities that are tackling health inequities. It presents a qualitative analysis further capturing information about specific community interventions involved in the exchange and identifying lessons learnt. This exchange was led by a partnership between the US Centers for Disease Control and Prevention, the International Union for Health Promotion and Education, the Department of Health of England, Health Action Partnership International, and Learning for Public Health West Midlands. These efforts provide interesting insights for further research, priority areas of action for policy and practice to address the SDH and to promote and sustain equity and social justice globally. The article highlights some key lessons about the use of data, assets-based community interventions and the importance of good leadership in times of crisis and adversity. Whilst complex and time-consuming to arrange, such programmes have the potential to offer other countries including the global south new insights and perspectives that will in turn contribute to the SDH field and provide concrete strategies and actions that effectively reduce inequities and promote the health of our societies. The key learnings have the potential to contribute to the global community and growing documentation on evidence of effective efforts in the reduction of health inequities.

Developing the Polynomial Expressions for Fields in the ITER Tokamak

NASA Astrophysics Data System (ADS)

Sharma, Stephen

2017-10-01

The two most important problems to be solved in the development of working nuclear fusion power plants are: sustained partial ignition and turbulence. These two phenomena are the subject of research and investigation through the development of analytic functions and computational models. Ansatz development through Gaussian wave-function approximations, dielectric quark models, field solutions using new elliptic functions, and better descriptions of the polynomials of the superconducting current loops are the critical theoretical developments that need to be improved. Euler-Lagrange equations of motion in addition to geodesic formulations generate the particle model which should correspond to the Dirac dispersive scattering coefficient calculations and the fluid plasma model. Feynman-Hellman formalism and Heaviside step functional forms are introduced to the fusion equations to produce simple expressions for the kinetic energy and loop currents. Conclusively, a polynomial description of the current loops, the Biot-Savart field, and the Lagrangian must be uncovered before there can be an adequate computational and iterative model of the thermonuclear plasma.

Expressions for Fields in the ITER Tokamak

NASA Astrophysics Data System (ADS)

Sharma, Stephen

2017-10-01

The two most important problems to be solved in the development of working nuclear fusion power plants are: sustained partial ignition and turbulence. These two phenomenon are the subject of research and investigation through the development of analytic functions and computational models. Ansatz development through Gaussian wave-function approximations, dielectric quark models, field solutions using new elliptic functions, and better descriptions of the polynomials of the superconducting current loops are the critical theoretical developments that need to be improved. Euler-Lagrange equations of motion in addition to geodesic formulations generate the particle model which should correspond to the Dirac dispersive scattering coefficient calculations and the fluid plasma model. Feynman-Hellman formalism and Heaviside step functional forms are introduced to the fusion equations to produce simple expressions for the kinetic energy and loop currents. Conclusively, a polynomial description of the current loops, the Biot-Savart field, and the Lagrangian must be uncovered before there can be an adequate computational and iterative model of the thermonuclear plasma.

Observation of maxillary incisive canal using dry skulls between Hellman's dental age IA and IIIC.

PubMed

Naitoh, Munetaka; Arikawa, Tomoko; Nishiyama, Wataru; Gotoh, Kenichi; Nawa, Hiroyuki; Fukuta, Osamu; Ariji, Eiichiro

2015-01-01

The maxillary incisive canals were observed in childhood from infancy to school-aged children to clarify their development. Cone-beam computed tomography was performed to investigate 44 dry child skulls. Two-dimensional images of various planes in the maxillary incisive canal were reconstructed on a computer using 3-dimensional visualization and measurement software. Then, antero-posterior angulation, and antero-posterior and lateral axes of the maxillary incisive canal were measured at the inferior and middle levels. The mean difference of angulation between the inferior and middle levels was 2.3 degrees in IIC, and 11.1 degrees in IIIC. The mean ratio of the lateral axis to antero-posterior axis at the middle level was 2.54 in IIC, and 1.93 in IIIC. In conclusion, it was antero-posteriorly straight from IA to IIC, and, after IIIA, it curved at the middle level. The cross-sectional shape in IIC was depressed with a larger lateral axis.

Financial Performance of Health Insurers: State-Run Versus Federal-Run Exchanges.

PubMed

Hall, Mark A; McCue, Michael J; Palazzolo, Jennifer R

2018-06-01

Many insurers incurred financial losses in individual markets for health insurance during 2014, the first year of Affordable Care Act mandated changes. This analysis looks at key financial ratios of insurers to compare profitability in 2014 and 2013, identify factors driving financial performance, and contrast the financial performance of health insurers operating in state-run exchanges versus the federal exchange. Overall, the median loss of sampled insurers was -3.9%, no greater than their loss in 2013. Reduced administrative costs offset increases in medical losses. Insurers performed better in states with state-run exchanges than insurers in states using the federal exchange in 2014. Medical loss ratios are the underlying driver more than administrative costs in the difference in performance between states with federal versus state-run exchanges. Policy makers looking to improve the financial performance of the individual market should focus on features that differentiate the markets associated with state-run versus federal exchanges.

Brain-wide pathway for waste clearance captured by contrast-enhanced MRI.

PubMed

Iliff, Jeffrey J; Lee, Hedok; Yu, Mei; Feng, Tian; Logan, Jean; Nedergaard, Maiken; Benveniste, Helene

2013-03-01

The glymphatic system is a recently defined brain-wide paravascular pathway for cerebrospinal fluid (CSF) and interstitial fluid (ISF) exchange that facilitates efficient clearance of solutes and waste from the brain. CSF enters the brain along para-arterial channels to exchange with ISF, which is in turn cleared from the brain along para-venous pathways. Because soluble amyloid β clearance depends on glymphatic pathway function, we proposed that failure of this clearance system contributes to amyloid plaque deposition and Alzheimer's disease progression. Here we provide proof of concept that glymphatic pathway function can be measured using a clinically relevant imaging technique. Dynamic contrast-enhanced MRI was used to visualize CSF-ISF exchange across the rat brain following intrathecal paramagnetic contrast agent administration. Key features of glymphatic pathway function were confirmed, including visualization of para-arterial CSF influx and molecular size-dependent CSF-ISF exchange. Whole-brain imaging allowed the identification of two key influx nodes at the pituitary and pineal gland recesses, while dynamic MRI permitted the definition of simple kinetic parameters to characterize glymphatic CSF-ISF exchange and solute clearance from the brain. We propose that this MRI approach may provide the basis for a wholly new strategy to evaluate Alzheimer's disease susceptibility and progression in the live human brain.

Brain-wide pathway for waste clearance captured by contrast-enhanced MRI

PubMed Central

Iliff, Jeffrey J.; Lee, Hedok; Yu, Mei; Feng, Tian; Logan, Jean; Nedergaard, Maiken; Benveniste, Helene

2013-01-01

The glymphatic system is a recently defined brain-wide paravascular pathway for cerebrospinal fluid (CSF) and interstitial fluid (ISF) exchange that facilitates efficient clearance of solutes and waste from the brain. CSF enters the brain along para-arterial channels to exchange with ISF, which is in turn cleared from the brain along para-venous pathways. Because soluble amyloid β clearance depends on glymphatic pathway function, we proposed that failure of this clearance system contributes to amyloid plaque deposition and Alzheimer’s disease progression. Here we provide proof of concept that glymphatic pathway function can be measured using a clinically relevant imaging technique. Dynamic contrast-enhanced MRI was used to visualize CSF-ISF exchange across the rat brain following intrathecal paramagnetic contrast agent administration. Key features of glymphatic pathway function were confirmed, including visualization of para-arterial CSF influx and molecular size-dependent CSF-ISF exchange. Whole-brain imaging allowed the identification of two key influx nodes at the pituitary and pineal gland recesses, while dynamic MRI permitted the definition of simple kinetic parameters to characterize glymphatic CSF-ISF exchange and solute clearance from the brain. We propose that this MRI approach may provide the basis for a wholly new strategy to evaluate Alzheimer’s disease susceptibility and progression in the live human brain. PMID:23434588

Quantum key distribution with finite resources: Secret key rates via Renyi entropies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abruzzo, Silvestre; Kampermann, Hermann; Mertz, Markus

A realistic quantum key distribution (QKD) protocol necessarily deals with finite resources, such as the number of signals exchanged by the two parties. We derive a bound on the secret key rate which is expressed as an optimization problem over Renyi entropies. Under the assumption of collective attacks by an eavesdropper, a computable estimate of our bound for the six-state protocol is provided. This bound leads to improved key rates in comparison to previous results.

The Department of Veterans Affairs' (VA) implementation of the Virtual Lifetime Electronic Record (VLER): findings and lessons learned from Health Information Exchange at 12 sites.

PubMed

Byrne, Colene M; Mercincavage, Lauren M; Bouhaddou, Omar; Bennett, Jamie R; Pan, Eric C; Botts, Nathan E; Olinger, Lois M; Hunolt, Elaine; Banty, Karl H; Cromwell, Tim

2014-08-01

We describe the Department of Veterans Affairs' (VA) Virtual Lifetime Health Electronic Record (VLER) pilot phase in 12 communities to exchange health information with private sector health care organizations and the Department of Defense (DoD), key findings, lessons, and implications for advancing Health Information Exchanges (HIE), nationally. A mixed methods approach was used to monitor and evaluate the status of VLER Health Exchange pilot phase implementation from December 2009 through October 2012. Selected accomplishments, contributions, challenges, and early lessons that are relevant to the growth of nationwide HIE are discussed. Veteran patient and provider acceptance, trust, and perceived value of VLER Health Exchange are found to be high, and usage by providers is steadily growing. Challenges and opportunities to improve provider use are identified, such as better data quality and integration with workflow. Key findings and lessons for advancing HIE are identified. VLER Health Exchange has made great strides in advancing HIE nationally by addressing important technical and policy issues that have impeded scalability, and by increasing trust and confidence in the value and accuracy of HIE among users. VLER Health Exchange has advanced HIE interoperability standards and patient consent policies nationally. Policy, programmatic, technology, and health Information Technology (IT) standards implications to advance HIE for improved delivery and coordination of health care are discussed. The pilot phase success led to VA-wide deployment of this data sharing capability in 2013. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Performance Analysis of MYSEA

DTIC Science & Technology

2012-09-01

Services FSD Federated Services Daemon I&A Identification and Authentication IKE Internet Key Exchange KPI Key Performance Indicator LAN Local Area...spection takes place in different processes in the server architecture. Key Performance Indica- tor ( KPI )s associated with the system need to be...application and risk analysis of security controls. Thus, measurement of the KPIs is needed before an informed tradeoff between the performance penalties

Continuous QKD and high speed data encryption

NASA Astrophysics Data System (ADS)

Zbinden, Hugo; Walenta, Nino; Guinnard, Olivier; Houlmann, Raphael; Wen, Charles Lim Ci; Korzh, Boris; Lunghi, Tommaso; Gisin, Nicolas; Burg, Andreas; Constantin, Jeremy; Legré, Matthieu; Trinkler, Patrick; Caselunghe, Dario; Kulesza, Natalia; Trolliet, Gregory; Vannel, Fabien; Junod, Pascal; Auberson, Olivier; Graf, Yoan; Curchod, Gilles; Habegger, Gilles; Messerli, Etienne; Portmann, Christopher; Henzen, Luca; Keller, Christoph; Pendl, Christian; Mühlberghuber, Michael; Roth, Christoph; Felber, Norbert; Gürkaynak, Frank; Schöni, Daniel; Muheim, Beat

2013-10-01

We present the results of a Swiss project dedicated to the development of high speed quantum key distribution and data encryption. The QKD engine features fully automated key exchange, hardware key distillation based on finite key security analysis, efficient authentication and wavelength division multiplexing of the quantum and the classical channel and one-time pas encryption. The encryption device allows authenticated symmetric key encryption (e.g AES) at rates of up to 100 Gb/s. A new quantum key can uploaded up to 1000 times second from the QKD engine.

Network and data security design for telemedicine applications.

PubMed

Makris, L; Argiriou, N; Strintzis, M G

1997-01-01

The maturing of telecommunication technologies has ushered in a whole new era of applications and services in the health care environment. Teleworking, teleconsultation, mutlimedia conferencing and medical data distribution are rapidly becoming commonplace in clinical practice. As a result, a set of problems arises, concerning data confidentiality and integrity. Public computer networks, such as the emerging ISDN technology, are vulnerable to eavesdropping. Therefore it is important for telemedicine applications to employ end-to-end encryption mechanisms securing the data channel from unauthorized access of modification. We propose a network access and encryption system that is both economical and easily implemented for integration in developing or existing applications, using well-known and thoroughly tested encryption algorithms. Public-key cryptography is used for session-key exchange, while symmetric algorithms are used for bulk encryption. Mechanisms for session-key generation and exchange are also provided.

Oxo-exchange of gas-phase uranyl, neptunyl, and plutonyl with water and methanol.

PubMed

Lucena, Ana F; Odoh, Samuel O; Zhao, Jing; Marçalo, Joaquim; Schreckenbach, Georg; Gibson, John K

2014-02-17

A challenge in actinide chemistry is activation of the strong bonds in the actinyl ions, AnO2(+) and AnO2(2+), where An = U, Np, or Pu. Actinyl activation in oxo-exchange with water in solution is well established, but the exchange mechanisms are unknown. Gas-phase actinyl oxo-exchange is a means to probe these processes in detail for simple systems, which are amenable to computational modeling. Gas-phase exchange reactions of UO2(+), NpO2(+), PuO2(+), and UO2(2+) with water and methanol were studied by experiment and density functional theory (DFT); reported for the first time are experimental results for UO2(2+) and for methanol exchange, as well as exchange rate constants. Key findings are faster exchange of UO2(2+) versus UO2(+) and faster exchange with methanol versus water; faster exchange of UO2(+) versus PuO2(+) was quantified. Computed potential energy profiles (PEPs) are in accord with the observed kinetics, validating the utility of DFT to model these exchange processes. The seemingly enigmatic result of faster exchange for uranyl, which has the strongest oxo-bonds, may reflect reduced covalency in uranyl as compared with plutonyl.

The use of fibrous ion exchangers in gold hydrometallurgy

NASA Astrophysics Data System (ADS)

Kautzmann, R. M.; Sampaio, C. H.; Cortina, J. L.; Soldatov, V.; Shunkevich, A.

2002-10-01

This article examines a family of ion-exchange fibers, FIBAN, containing primary and secondary amine groups. These ion exchangers have a fiber diameter of 20 40 Μm, high osmotic and mechanic stability, a high rate of adsorption and regeneration, and excellent dynamic characteristics as filtering media. Inparticular, this article discusses the use of FIBAN fibrous ion exchangers in the recovery of gold cyanide andbase-metal cyanides (copper and mercury) from mineral-leaching solutions. The influence of polymer structure and water content on their extraction ability is described, along with key parameters of gold hydrometallurgy such as extraction efficiency, selectivity, pH dependence, gold cyanide loading, kinetics, and stripping.

Moderate water stress from regulated deficit irrigation decreases transpiration similarly to net carbon exchange in grapevine canopies

USDA-ARS?s Scientific Manuscript database

To determine the effects of timing and extent of regulated deficit irrigation (RDI) on grapevine (Vitis vinifera) canopies, whole-canopy transpiration (TrV) and canopy conductance to water vapor (gc) were calculated from whole-vine gas exchange near key stages of fruit development. The vines were ma...

The Iterative Design of a Virtual Design Studio

ERIC Educational Resources Information Center

Blevis, Eli; Lim, Youn-kyung; Stolterman, Erik; Makice, Kevin

2008-01-01

In this article, the authors explain how they implemented Design eXchange as a shared collaborative online and physical space for design for their students. Their notion for Design eXchange favors a complex mix of key elements namely: (1) a virtual online studio; (2) a forum for review of all things related to design, especially design with the…

Knowledge Exchange: Capacity Building in a Small University

ERIC Educational Resources Information Center

Davis, Sally Fowler

2009-01-01

Purpose: The aim of this paper is to examine an early articulation of some of the key factors in building capacity and the potential for knowledge exchange (KE) within a small, learning and teaching-oriented organization. Design/methodology/approach: An action research study is planned as a practical enquiry. In common with other action research,…

Positive exchange-bias and giant vertical hysteretic shift in La0.3Sr0.7FeO3/SrRuO3 bilayers

PubMed Central

Rana, Rakesh; Pandey, Parul; Singh, R. P.; Rana, D. S.

2014-01-01

The exchange-bias effects in the mosaic epitaxial bilayers of the itinerant ferromagnet (FM) SrRuO3 and the antiferromagnetic (AFM) charge-ordered La0.3Sr0.7FeO3 were investigated. An uncharacteristic low-field positive exchange bias, a cooling-field driven reversal of positive to negative exchange-bias and a layer thickness optimised unusual vertical magnetization shift were all novel facets of exchange bias realized for the first time in magnetic oxides. The successive magnetic training induces a transition from positive to negative exchange bias regime with changes in domain configurations. These observations are well corroborated by the hysteretic loop asymmetries which display the modifications in the AFM spin correlations. These exotic features emphasize the key role of i) mosaic disorder induced subtle interplay of competing AFM-superexchange and FM double exchange at the exchange biased interface and, ii) training induced irrecoverable alterations in the AFM spin structure. PMID:24569516

Proton channels and exchangers in cancer.

PubMed

Spugnini, Enrico Pierluigi; Sonveaux, Pierre; Stock, Christian; Perez-Sayans, Mario; De Milito, Angelo; Avnet, Sofia; Garcìa, Abel Garcìa; Harguindey, Salvador; Fais, Stefano

2015-10-01

Although cancer is characterized by an intratumoral genetic heterogeneity, a totally deranged pH control is a common feature of most cancer histotypes. Major determinants of aberrant pH gradient in cancer are proton exchangers and transporters, including V-ATPase, Na+/H+ exchanger (NHE), monocarboxylate transporters (MCTs) and carbonic anhydrases (CAs). Thanks to the activity of these proton transporters and exchangers, cancer becomes isolated and/or protected not only from the body reaction against the growing tumor, but also from the vast majority of drugs that when protonated into the acidic tumor microenvironment do not enter into cancer cells. Proton transporters and exchangers represent a key feature tumor cells use to survive in the very hostile microenvironmental conditions that they create and maintain. Detoxifying mechanisms may thus represent both a key survival option and a selection outcome for cells that behave as unicellular microorganisms rather than belonging to an organ, compartment or body. It is, in fact, typical of malignant tumors that, after a clinically measurable yet transient initial response to a therapy, resistant tumor clones emerge and proliferate, thus bursting a more malignant behavior and rapid tumor progression. This review critically presents the background of a novel and efficient approach that aims to fight cancer through blocking or inhibiting well characterized proton exchangers and transporters active in human cancer cells. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers. Copyright © 2014 Elsevier B.V. All rights reserved.

The use of conferencing technologies to support drug policy group knowledge exchange processes: an action case approach.

PubMed

Househ, Mowafa Said; Kushniruk, Andre; Maclure, Malcolm; Carleton, Bruce; Cloutier-Fisher, Denise

2011-04-01

To describe experiences, lessons and the implications related to the use of conferencing technology to support three drug policy research groups within a three-year period, using the action case research method. An action case research field study was executed. Three different drug policy groups participated: research, educator, and decision-maker task groups. There were a total of 61 participants in the study. The study was conducted between 2004 and 2007. Each group used audio-teleconferencing, web-conferencing or both to support their knowledge exchange activities. Data were collected over three years and consisted of observation notes, interviews, and meeting transcripts. Content analysis was used to analyze the data using NIVIO qualitative data analysis software. The study found six key lessons regarding the impact of conferencing technologies on knowledge exchange within drug policy groups. We found that 1) groups adapt to technology to facilitate group communication, 2) web-conferencing communication is optimal under certain conditions, 3) audio conferencing is convenient, 4) web-conferencing forces group interactions to be "within text", 5) facilitation contributes to successful knowledge exchange, and 6) technology impacts information sharing. This study highlights lessons related to the use of conferencing technologies to support distant knowledge exchange within drug policy groups. Key lessons from this study can be used by drug policy groups to support successful knowledge exchange activities using conferencing technologies. 2010 Elsevier Ireland Ltd. All rights reserved.

SeaQuaKE: Sea-Optimized Quantum Key Exchange

DTIC Science & Technology

2014-08-01

which is led by Applied Communications Sciences under the ONR Free Space Optical Quantum Key Distribution Special Notice (13-SN-0004 under ONRBAA13...aerosol model scenarios. 15. SUBJECT TERMS Quantum communications, free - space optical communications 16. SECURITY CLASSIFICATION OF: 17...SeaQuaKE) project, which is led by Applied Communications Sciences under the ONR Free Space Optical Quantum Key Distribution Special Notice (13-SN

Keys to Success in Raising Funds: An Exchange Classic.

ERIC Educational Resources Information Center

Neugebauer, Roger

2001-01-01

Details survey of over 100 child care centers about successful and unsuccessful fundraising projects. Highlights ten key factors contributing to success: defining the purpose for fundraising, setting a goal, knowing the audience, making it fun, building on strengths, looking for repeated fundraisers, being cost effective, publicizing aggressively,…

Experimental Observation of Spin-Exchange in Ultracold Fermi Gases

NASA Astrophysics Data System (ADS)

Peng, Peng; Huang, Liang-Hui; Li, Dong-Hao; Meng, Zeng-Ming; Wang, Peng-Jun; Zhang, Jing

2018-03-01

Not Available Supported by the National Key Research and Development Program of China under Grant Nos 2016YFA0301600 and 2016YFA0301602, the National Natural Science Foundation of China under Grant Nos 11234008, 11474188 and 11704234, and the Fund for Shanxi ‘1331 Project’ Key Subjects Construction.

Effect of currency exchange rate fluctuations on Aid Effectiveness in the Health Sector in Zambia.

PubMed

Chansa, Collins; Sundewall, Jesper; Östlund, Numi

2018-06-22

Development assistance for health (DAH) remains a significant and important source of health financing in many low and lower middle-income countries. However, this assistance has not been fully effective. This study explores the effect of currency exchange rate fluctuations on volatility of DAH in Zambia using a mixed methods approach. Data covering the period 1997-2008 were collected from various financial and programmatic reports, while six key informant interviews were conducted to validate and translate findings from the quantitative analysis. Results show fluctuations in the volume of funds disbursed to the Ministry of Health by donors due to changes in the exchange rates between non-US$ currencies and the US$, ranging from -11.1% to +13.4% during the period 1997-2008. The overall effect was a loss of US$ 13.4 million over the period 1997-2008 which is equivalent to an annual average loss of US$ 1.1 million per annum. There were also fluctuations in the US$ amount that was converted to the Zambian Kwacha to fund districts ranging from -22% to +22% over the same period. The monthly average loss that was incurred was US$ 302 214 per month, but large gains and losses were observed when individual months were analysed. Information from key informants suggest that currency exchange rate losses contribute to reductions in the health workforce, quantity and quality of health services, while currency exchange rate gains can contribute to reduced absorption capacity and/or low utilization of financial resources. The study concludes that fluctuations in currency exchange rates contribute to volatility in DAH, reduces financial stability and leads to unpredictability of DAH which ultimately affects health service delivery. For DAH to be effective, governments and donors should increase awareness and work systematically to mitigate currency exchange risks.

Patients’ Data Management System Protected by Identity-Based Authentication and Key Exchange

PubMed Central

Rivero-García, Alexandra; Santos-González, Iván; Hernández-Goya, Candelaria; Caballero-Gil, Pino; Yung, Moti

2017-01-01

A secure and distributed framework for the management of patients’ information in emergency and hospitalization services is proposed here in order to seek improvements in efficiency and security in this important area. In particular, confidentiality protection, mutual authentication, and automatic identification of patients are provided. The proposed system is based on two types of devices: Near Field Communication (NFC) wristbands assigned to patients, and mobile devices assigned to medical staff. Two other main elements of the system are an intermediate server to manage the involved data, and a second server with a private key generator to define the information required to protect communications. An identity-based authentication and key exchange scheme is essential to provide confidential communication and mutual authentication between the medical staff and the private key generator through an intermediate server. The identification of patients is carried out through a keyed-hash message authentication code. Thanks to the combination of the aforementioned tools, a secure alternative mobile health (mHealth) scheme for managing patients’ data is defined for emergency and hospitalization services. Different parts of the proposed system have been implemented, including mobile application, intermediate server, private key generator and communication channels. Apart from that, several simulations have been performed, and, compared with the current system, significant improvements in efficiency have been observed. PMID:28362328

Patients' Data Management System Protected by Identity-Based Authentication and Key Exchange.

PubMed

Rivero-García, Alexandra; Santos-González, Iván; Hernández-Goya, Candelaria; Caballero-Gil, Pino; Yung, Moti

2017-03-31

A secure and distributed framework for the management of patients' information in emergency and hospitalization services is proposed here in order to seek improvements in efficiency and security in this important area. In particular, confidentiality protection, mutual authentication, and automatic identification of patients are provided. The proposed system is based on two types of devices: Near Field Communication (NFC) wristbands assigned to patients, and mobile devices assigned to medical staff. Two other main elements of the system are an intermediate server to manage the involved data, and a second server with a private key generator to define the information required to protect communications. An identity-based authentication and key exchange scheme is essential to provide confidential communication and mutual authentication between the medical staff and the private key generator through an intermediate server. The identification of patients is carried out through a keyed-hash message authentication code. Thanks to the combination of the aforementioned tools, a secure alternative mobile health (mHealth) scheme for managing patients' data is defined for emergency and hospitalization services. Different parts of the proposed system have been implemented, including mobile application, intermediate server, private key generator and communication channels. Apart from that, several simulations have been performed, and, compared with the current system, significant improvements in efficiency have been observed.

New Leeway on Horizon under NCLB

ERIC Educational Resources Information Center

McNeil, Michele

2011-01-01

As the clock ticks toward President Barack Obama's back-to-school deadline for rewriting the No Child Left Behind Act, U.S. Secretary of Education Arne Duncan is preparing to grant states relief from key provisions of the federal school accountability law in exchange for what he calls "commitments to key reforms." The move comes as…

A large-alphabet three-party quantum key distribution protocol based on orbital and spin angular momenta hybrid entanglement

NASA Astrophysics Data System (ADS)

Lai, Hong; Luo, Mingxing; Zhang, Jun; Pieprzyk, Josef; Pan, Lei; Orgun, Mehmet A.

2018-07-01

The orthogonality of the orbital angular momentum (OAM) eigenstates enables a single photon carry an arbitrary number of bits. Moreover, additional degrees of freedom (DOFs) of OAM can span a high-dimensional Hilbert space, which could greatly increase information capacity and security. Moreover, the use of the spin angular momentum-OAM hybrid entangled state can increase Shannon dimensionality, because photons can be hybrid entangled in multiple DOFs. Based on these observations, we develop a hybrid entanglement quantum key distribution (QKD) protocol to achieve three-party quantum key distribution without classical message exchanges. In our proposed protocol, a communicating party uses a spatial light modulator (SLM) and a specific phase hologram to modulate photons' OAM state. Similarly, the other communicating parties use their SLMs and the fixed different phase holograms to modulate the OAM entangled photon pairs, producing the shared key among the parties Alice, Bob and Charlie without classical message exchanges. More importantly, when the same operation is repeated for every party, our protocol could be extended to a multiple-party QKD protocol.

Second-order schedules of token reinforcement with pigeons: effects of fixed- and variable-ratio exchange schedules.

PubMed

Foster, T A; Hackenberg, T D; Vaidya, M

2001-09-01

Pigeons' key pecks produced food under second-order schedules of token reinforcement, with light-emitting diodes serving as token reinforcers. In Experiment 1, tokens were earned according to a fixed-ratio 50 schedule and were exchanged for food according to either fixed-ratio or variable-ratio exchange schedules, with schedule type varied across conditions. In Experiment 2, schedule type was varied within sessions using a multiple schedule. In one component, tokens were earned according to a fixed-ratio 50 schedule and exchanged according to a variable-ratio schedule. In the other component, tokens were earned according to a variable-ratio 50 schedule and exchanged according to a fixed-ratio schedule. In both experiments, the number of responses per exchange was varied parametrically across conditions, ranging from 50 to 400 responses. Response rates decreased systematically with increases in the fixed-ratio exchange schedules, but were much less affected by changes in the variable-ratio exchange schedules. Response rates were consistently higher under variable-ratio exchange schedules than tinder comparable fixed-ratio exchange schedules, especially at higher exchange ratios. These response-rate differences were due both to greater pre-ratio pausing and to lower local rates tinder the fixed-ratio exchange schedules. Local response rates increased with proximity to food under the higher fixed-ratio exchange schedules, indicative of discriminative control by the tokens.

Bioinformatics data distribution and integration via Web Services and XML.

PubMed

Li, Xiao; Zhang, Yizheng

2003-11-01

It is widely recognized that exchange, distribution, and integration of biological data are the keys to improve bioinformatics and genome biology in post-genomic era. However, the problem of exchanging and integrating biology data is not solved satisfactorily. The eXtensible Markup Language (XML) is rapidly spreading as an emerging standard for structuring documents to exchange and integrate data on the World Wide Web (WWW). Web service is the next generation of WWW and is founded upon the open standards of W3C (World Wide Web Consortium) and IETF (Internet Engineering Task Force). This paper presents XML and Web Services technologies and their use for an appropriate solution to the problem of bioinformatics data exchange and integration.

An eCK-Secure Authenticated Key Exchange Protocol without Random Oracles

NASA Astrophysics Data System (ADS)

Moriyama, Daisuke; Okamoto, Tatsuaki

This paper presents a (PKI-based) two-pass authenticated key exchange (AKE) protocol that is secure in the extended Canetti-Krawczyk (eCK) security model. The security of the proposed protocol is proven without random oracles (under three assumptions), and relies on no implementation techniques such as a trick by LaMacchia, Lauter and Mityagin (so-called the NAXOS trick). Since an AKE protocol that is eCK-secure under a NAXOS-like implementation trick will be no more eCK-secure if some realistic information leakage occurs through side-channel attacks, it has been an important open problem how to realize an eCK-secure AKE protocol without using the NAXOS tricks (and without random oracles).

Analysis of a Decision Support System for CASE Tool Selection and the Specification of an Ada to SQL Abstract Interface

DTIC Science & Technology

1991-12-01

34 foreign keys" ,which are keys inherited from conlected entities, the keys would already be defined in the connected entity’s domain primiti le definition...defined for the rootnode re!ationship because all attributes are foreign keys and they are already defined in the connected entities domain primitive...can exchange data with other tools including other tools in the tool vendor’s tool 99 Upper CASE Tool Charactcrizcs set. The important attributes are

Quantum dialogue by nonselective measurements

NASA Astrophysics Data System (ADS)

Nguyen, Ba An

2018-06-01

Unlike classical measurements, quantum measurements may be useful even without reading the outcome. Such so called nonselective measurements are exploited in this paper to design a quantum dialogue protocol that allows exchanging secret data without prior key distributions. The relevant data to be exchanged are in terms of the high-dimensional mutually unbiased bases of quantum measurements. Appropriate modes of bidirectional controlling are devised to ensure the protocol security which is asymptotic.

University Knowledge Exchange (KE) Framework: Good Practice in Technology Transfer. Report to the UK Higher Education Sector and HEFCE by the McMillan Group

ERIC Educational Resources Information Center

Higher Education Funding Council for England, 2016

2016-01-01

As part of its commitment to keeping the UK at the leading edge as a global knowledge-based economy, the last Government asked the Higher Education Funding Council for England (HEFCE) in 2014 to develop a knowledge exchange (KE) performance framework that would secure effective practice in universities on key productive elements in the…

Fair relationships and policies to support family day care educators' mental health: a qualitative study.

PubMed

Corr, Lara; Davis, Elise; Cook, Kay; Waters, Elizabeth; LaMontagne, Anthony D

2014-11-25

High quality child care is a population health investment that relies on the capacity of providers. The mental health and wellbeing of child care educators is fundamental to care quality and turnover, yet sector views on the relationship between working conditions and mental health and wellbeing are scarce. This paper examines child care educators' and sector key informants' perspectives on how working in family day care influences educator's mental health and wellbeing. Semi-structured telephone interviews were conducted with Australian family day care educators (n = 16) and key informants (n = 18) comprised of representatives from family day care schemes, government and other relevant organisations regarding the relationship between working conditions and educator mental health. Thematic analysis referenced the assumptions and concepts of critical inquiry and used social exchange theory. Educators and key informants reported that educators' mental health was affected by the quality of their relationships with government, family day care schemes, and the parents and children using their services. These social relationships created and contributed to working conditions that were believed to promote or diminish educators' mental health. High quality relationships featured fair exchanges of educator work for key resources of social support and respect; adequate income; professional services; and information. Crucially, how exchanges influenced educator wellbeing was largely contingent on government policies that reflect the values and inequities present in society. Making policies and relationships between educators, government and family day care schemes fairer would contribute strongly to the protection and promotion of educator mental health and wellbeing, and in turn contribute to workforce stability and care quality.

Marrying Up by Marrying Down: Status Exchange between Social Origin and Education in the United States.

PubMed

Schwartz, Christine R; Zeng, Zhen; Xie, Yu

2016-11-01

Intermarriage plays a key role in stratification systems. Spousal resemblance reinforces social boundaries within and across generations, and the rules of intermarriage govern the ways that social mobility may occur. We examine intermarriage across social origin and education boundaries in the United States using data from the 1968-2013 Panel Study of Income Dynamics. Our evidence points to a pattern of status exchange-that is, persons with high education from modest backgrounds tend to marry those with lower education from more privileged backgrounds. Our study contributes to an active methodological debate by pinpointing the conditions under which the results pivot from evidence against exchange to evidence for exchange and advances theory by showing that the rules of exchange are more consistent with the notion of diminishing marginal utility than the more general theory of compensating differentials.

The evolutionary synchronization of the exchange rate system in ASEAN+6

NASA Astrophysics Data System (ADS)

Feng, Xiaobing; Hu, Haibo; Wang, Xiaofan

2010-12-01

Although there are extensive researches on the behavior of the world currency network, the complexity of the Asian regional currency system is not well understood regardless of its importance. Using daily exchange rates this paper examines exchange rate co-movements in the region before and after the China exchange rate reform. It was found that the correlation between Asian currencies and the US Dollar, the previous regional key currency has become weaker and intra-Asia interactions have increased. Cross sample entropy and cross entropy approaches are also applied to examine the synchrony behavior among the Asian currencies. The study also shows that the Asian exchange rate markets featured are neither stochastic nor efficient. These findings may shed some light on the in-depth understanding of collective behaviors in a regional currency network; they will also lay a theoretical foundation for further policy formulation in Asian currency integration.

Ultrafast spin exchange-coupling torque via photo-excited charge-transfer processes

NASA Astrophysics Data System (ADS)

Ma, X.; Fang, F.; Li, Q.; Zhu, J.; Yang, Y.; Wu, Y. Z.; Zhao, H. B.; Lüpke, G.

2015-10-01

Optical control of spin is of central importance in the research of ultrafast spintronic devices utilizing spin dynamics at short time scales. Recently developed optical approaches such as ultrafast demagnetization, spin-transfer and spin-orbit torques open new pathways to manipulate spin through its interaction with photon, orbit, charge or phonon. However, these processes are limited by either the long thermal recovery time or the low-temperature requirement. Here we experimentally demonstrate ultrafast coherent spin precession via optical charge-transfer processes in the exchange-coupled Fe/CoO system at room temperature. The efficiency of spin precession excitation is significantly higher and the recovery time of the exchange-coupling torque is much shorter than for the demagnetization procedure, which is desirable for fast switching. The exchange coupling is a key issue in spin valves and tunnelling junctions, and hence our findings will help promote the development of exchange-coupled device concepts for ultrafast coherent spin manipulation.

Efficient Fair Exchange from Identity-Based Signature

NASA Astrophysics Data System (ADS)

Yum, Dae Hyun; Lee, Pil Joong

A fair exchange scheme is a protocol by which two parties Alice and Bob exchange items or services without allowing either party to gain advantages by quitting prematurely or otherwise misbehaving. To this end, modern cryptographic solutions use a semi-trusted arbitrator who involves only in cases where one party attempts to cheat or simply crashes. We call such a fair exchange scheme optimistic. When no registration is required between the signer and the arbitrator, we say that the fair exchange scheme is setup free. To date, the setup-free optimist fair exchange scheme under the standard RSA assumption was only possible from the generic construction of [12], which uses ring signatures. In this paper, we introduce a new setup-free optimistic fair exchange scheme under the standard RSA assumption. Our scheme uses the GQ identity-based signature and is more efficient than [12]. The construction can also be generalized by using various identity-based signature schemes. Our main technique is to allow each user to choose his (or her) own “random” public key in the identitybased signature scheme.

MN15-L: A New Local Exchange-Correlation Functional for Kohn-Sham Density Functional Theory with Broad Accuracy for Atoms, Molecules, and Solids.

PubMed

Yu, Haoyu S; He, Xiao; Truhlar, Donald G

2016-03-08

Kohn-Sham density functional theory is widely used for applications of electronic structure theory in chemistry, materials science, and condensed-matter physics, but the accuracy depends on the quality of the exchange-correlation functional. Here, we present a new local exchange-correlation functional called MN15-L that predicts accurate results for a broad range of molecular and solid-state properties including main-group bond energies, transition metal bond energies, reaction barrier heights, noncovalent interactions, atomic excitation energies, ionization potentials, electron affinities, total atomic energies, hydrocarbon thermochemistry, and lattice constants of solids. The MN15-L functional has the same mathematical form as a previous meta-nonseparable gradient approximation exchange-correlation functional, MN12-L, but it is improved because we optimized it against a larger database, designated 2015A, and included smoothness restraints; the optimization has a much better representation of transition metals. The mean unsigned error on 422 chemical energies is 2.32 kcal/mol, which is the best among all tested functionals, with or without nonlocal exchange. The MN15-L functional also provides good results for test sets that are outside the training set. A key issue is that the functional is local (no nonlocal exchange or nonlocal correlation), which makes it relatively economical for treating large and complex systems and solids. Another key advantage is that medium-range correlation energy is built in so that one does not need to add damped dispersion by molecular mechanics in order to predict accurate noncovalent binding energies. We believe that the MN15-L functional should be useful for a wide variety of applications in chemistry, physics, materials science, and molecular biology.

Medication incident reporting in residential aged care facilities: Limitations and risks to residents’ safety

PubMed Central

2012-01-01

Background Medication incident reporting (MIR) is a key safety critical care process in residential aged care facilities (RACFs). Retrospective studies of medication incident reports in aged care have identified the inability of existing MIR processes to generate information that can be used to enhance residents’ safety. However, there is little existing research that investigates the limitations of the existing information exchange process that underpins MIR, despite the considerable resources that RACFs’ devote to the MIR process. The aim of this study was to undertake an in-depth exploration of the information exchange process involved in MIR and identify factors that inhibit the collection of meaningful information in RACFs. Methods The study was undertaken in three RACFs (part of a large non-profit organisation) in NSW, Australia. A total of 23 semi-structured interviews and 62 hours of observation sessions were conducted between May to July 2011. The qualitative data was iteratively analysed using a grounded theory approach. Results The findings highlight significant gaps in the design of the MIR artefacts as well as information exchange issues in MIR process execution. Study results emphasized the need to: a) design MIR artefacts that facilitate identification of the root causes of medication incidents, b) integrate the MIR process within existing information systems to overcome key gaps in information exchange execution, and c) support exchange of information that can facilitate a multi-disciplinary approach to medication incident management in RACFs. Conclusions This study highlights the advantages of viewing MIR process holistically rather than as segregated tasks, as a means to identify gaps in information exchange that need to be addressed in practice to improve safety critical processes. PMID:23122411

J-PAKE: Authenticated Key Exchange without PKI

NASA Astrophysics Data System (ADS)

Hao, Feng; Ryan, Peter

Password Authenticated Key Exchange (PAKE) is one of the important topics in cryptography. It aims to address a practical security problem: how to establish secure communication between two parties solely based on a shared password without requiring a Public Key Infrastructure (PKI). After more than a decade of extensive research in this field, there have been several PAKE protocols available. The EKE and SPEKE schemes are perhaps the two most notable examples. Both techniques are however patented. In this paper, we review these techniques in detail and summarize various theoretical and practical weaknesses. In addition, we present a new PAKE solution called J-PAKE. Our strategy is to depend on well-established primitives such as the Zero-Knowledge Proof (ZKP). So far, almost all of the past solutions have avoided using ZKP for the concern on efficiency. We demonstrate how to effectively integrate the ZKP into the protocol design and meanwhile achieve good efficiency. Our protocol has comparable computational efficiency to the EKE and SPEKE schemes with clear advantages on security.

A General Method for Predicting Amino Acid Residues Experiencing Hydrogen Exchange

PubMed Central

Wang, Boshen; Perez-Rathke, Alan; Li, Renhao; Liang, Jie

2018-01-01

Information on protein hydrogen exchange can help delineate key regions involved in protein-protein interactions and provides important insight towards determining functional roles of genetic variants and their possible mechanisms in disease processes. Previous studies have shown that the degree of hydrogen exchange is affected by hydrogen bond formations, solvent accessibility, proximity to other residues, and experimental conditions. However, a general predictive method for identifying residues capable of hydrogen exchange transferable to a broad set of proteins is lacking. We have developed a machine learning method based on random forest that can predict whether a residue experiences hydrogen exchange. Using data from the Start2Fold database, which contains information on 13,306 residues (3,790 of which experience hydrogen exchange and 9,516 which do not exchange), our method achieves good performance. Specifically, we achieve an overall out-of-bag (OOB) error, an unbiased estimate of the test set error, of 20.3 percent. Using a randomly selected test data set consisting of 500 residues experiencing hydrogen exchange and 500 which do not, our method achieves an accuracy of 0.79, a recall of 0.74, a precision of 0.82, and an F1 score of 0.78.

Enhanced bimolecular exchange reaction through programmed coordination of a five-coordinate oxovanadium complex for efficient redox mediation in dye-sensitized solar cells.

PubMed

Oyaizu, Kenichi; Hayo, Noriko; Sasada, Yoshito; Kato, Fumiaki; Nishide, Hiroyuki

2013-12-07

Electrochemical reversibility and fast bimolecular exchange reaction found for VO(salen) gave rise to a highly efficient redox mediation to enhance the photocurrent of a dye-sensitized solar cell, leading to an excellent photovoltaic performance with a conversion efficiency of 5.4%. A heterogeneous electron-transfer rate constant at an electrode (k0) and a second-order rate constant for an electron self-exchange reaction (k(ex)) were proposed as key parameters that dominate the charge transport property, which afforded a novel design concept for the mediators based on their kinetic aspects.

Harnessing Private-Sector Innovation to Improve Health Insurance Exchanges.

PubMed

Gresenz, Carole Roan; Hoch, Emily; Eibner, Christine; Rudin, Robert S; Mattke, Soeren

2016-05-09

Overhauling the individual health insurance market-including through the creation of health insurance exchanges-was a key component of the Patient Protection and Affordable Care Act's multidimensional approach to addressing the long-standing problem of the uninsured in the United States. Despite succeeding in enrolling millions of Americans, the exchanges still face several challenges, including poor consumer experience, high operational and development costs, and incomplete market penetration. In light of these challenges, analysts considered a different model for the exchanges-privately facilitated exchanges-which could address these challenges and deepen the Affordable Care Act's impact. In this model, the government retains control over sovereign exchange functions but allows the private sector to assume responsibility for more-peripheral exchange functions, such as developing and sustaining exchange websites. Although private-sector entities have already undertaken exchange-related functions on a limited basis, privately facilitated exchanges could conceivably relieve the government of its responsibility for front-end website operations and consumer decision-support functions entirely. A shift to privately facilitated exchanges could improve the consumer experience, increase enrollment, and lower costs for state and federal governments. A move to such a model requires, nonetheless, managing its risks, such as reduced consumer protection, increased consumer confusion, and the possible lack of a viable revenue base for privately facilitated exchanges, especially in less populous states. On net, the benefits are large enough and the risks sufficiently manageable to seriously consider such a shift. This paper provides background information and more detail on the analysts' assessment.

Physician capability to electronically exchange clinical information, 2011.

PubMed

Patel, Vaishali; Swain, Matthew J; King, Jennifer; Furukawa, Michael F

2013-10-01

To provide national estimates of physician capability to electronically share clinical information with other providers and to describe variation in exchange capability across states and electronic health record (EHR) vendors using the 2011 National Ambulatory Medical Care Survey Electronic Medical Record Supplement. Survey of a nationally representative sample of nonfederal office-based physicians who provide direct patient care. The survey was administered by mail with telephone follow-up and had a 61% weighted response rate. The overall sample consisted of 4326 respondents. We calculated estimates of electronic exchange capability at the national and state levels, and applied multivariate analyses to examine the association between the capability to exchange different types of clinical information and physician and practice characteristics. In 2011, 55% of physicians had computerized capability to send prescriptions electronically; 67% had the capability to view lab results electronically; 42% were able to incorporate lab results into their EHR; 35% were able to send lab orders electronically; and, 31% exchanged patient clinical summaries with other providers. The strongest predictor of exchange capability is adoption of an EHR. However, substantial variation exists across geography and EHR vendors in exchange capability, especially electronic exchange of clinical summaries. In 2011, a majority of office-based physicians could exchange lab and medication data, and approximately one-third could exchange clinical summaries with patients or other providers. EHRs serve as a key mechanism by which physicians can exchange clinical data, though physicians' capability to exchange varies by vendor and by state.

Correlation networks among currencies

NASA Astrophysics Data System (ADS)

Mizuno, Takayuki; Takayasu, Hideki; Takayasu, Misako

2006-05-01

By analyzing the foreign exchange market data of various currencies, we derive a hierarchical taxonomy of currencies constructing minimal-spanning trees. Clustered structure of the currencies and the key currency in each cluster are found. The clusters match nicely with the geographical regions of corresponding countries in the world such as Asia or East Europe, the key currencies are generally given by major economic countries as expected.

Common Criteria for Information Technology Security Evaluation: Department of Defense Public Key Infrastructure and Key Management Infrastructure Token Protection Profile (Medium Robustness)

DTIC Science & Technology

2002-03-22

may be derived from detailed inspection of the IC itself or from illicit appropriation of design information. Counterfeit smart cards can be mass...Infrastructure (PKI) as the Internet to securely and privately exchange data and money through the use of a public and a private cryptographic key pair...interference devices (SQDIS), electrical testing, and electron beam testing. • Other attacks, such as UV or X-rays or high temperatures, could cause erasure

Study of Fluid Cooling Loop System in Chinese Manned Spacecraft

NASA Astrophysics Data System (ADS)

Jiang, Jun; Xu, Jiwan; Fan, Hanlin; Huang, Jiarong

2002-01-01

change. To solve the questions, a fluid cooling loop system must be applied to Chinese manned spacecraft besides other conventional thermal control methods, such as thermal control coatings, multiplayer insulation blankets, heat pipes, electro-heating adjustment temperature devices, and so on. The paper will introduce the thermal design of inner and outer fluid loop including their constitution and fundamental, etc. The capability of heat transportation and the accuracy of control temperature for the fluid loop will be evaluated and analyzed. To insure the air temperature of sealed cabins within 21+/-4, the inlet liquid temperature of condensing heat exchanger needs to be controlled within 9+/-2. To insure this, the inlet liquid temperature of middle heat exchanger needs to be controlled within 8+/-1.8. The inlet temperature point is controlled by a subsidiary loop adjusting: when the computer receives feedbacks of the deviation and the variety rate of deviation from the controlled temperature point. It drives the temperature control valve to adjust the flow flux distribution between the main loop through radiator and the subsidiary loop which isn't through radiator to control the temperature of the mixed fluid within 8+/-1.8. The paper will also introduce thermal designs of key parts in the cooling loop, such as space radiators, heat exchangers and cooling plates. Thermal simulated tests on the ground and flight tests have been performed to verify correctness of thermal designs. rational and the loop system works order. It realizes the circulation of absorbing heat dissipation to the loop and transferring it to radiator then radiating it to space. (2) loop control system controls inlet temperature of middle heat exchanger within 8+/-1.8 under various thermal cases. Thermal design of the middle heat exchanger insures inlet temperature of condensing heat within 9+/-2. Thereby, the air temperature of sealed cabins is controlled within about 21+/-4 accurately. (3) The thermal designs of the key heat exchanging parts (such as radiator, heat exchangers and cooling plates) in the cooling loop are rational and effective, they meet the requirements of heat exchanging and assure the entire system work order.

Hydrogen exchange differences between chemoreceptor signaling complexes localize to functionally important subdomains.

PubMed

Koshy, Seena S; Li, Xuni; Eyles, Stephen J; Weis, Robert M; Thompson, Lynmarie K

2014-12-16

The goal of understanding mechanisms of transmembrane signaling, one of many key life processes mediated by membrane proteins, has motivated numerous studies of bacterial chemotaxis receptors. Ligand binding to the receptor causes a piston motion of an α helix in the periplasmic and transmembrane domains, but it is unclear how the signal is then propagated through the cytoplasmic domain to control the activity of the associated kinase CheA. Recent proposals suggest that signaling in the cytoplasmic domain involves opposing changes in dynamics in different subdomains. However, it has been difficult to measure dynamics within the functional system, consisting of extended arrays of receptor complexes with two other proteins, CheA and CheW. We have combined hydrogen exchange mass spectrometry with vesicle template assembly of functional complexes of the receptor cytoplasmic domain to reveal that there are significant signaling-associated changes in exchange, and these changes localize to key regions of the receptor involved in the excitation and adaptation responses. The methylation subdomain exhibits complex changes that include slower hydrogen exchange in complexes in a kinase-activating state, which may be partially consistent with proposals that this subdomain is stabilized in this state. The signaling subdomain exhibits significant protection from hydrogen exchange in complexes in a kinase-activating state, suggesting a tighter and/or larger interaction interface with CheA and CheW in this state. These first measurements of the stability of protein subdomains within functional signaling complexes demonstrate the promise of this approach for measuring functionally important protein dynamics within the various physiologically relevant states of multiprotein complexes.

Hydrogen Exchange Differences between Chemoreceptor Signaling Complexes Localize to Functionally Important Subdomains

PubMed Central

2015-01-01

The goal of understanding mechanisms of transmembrane signaling, one of many key life processes mediated by membrane proteins, has motivated numerous studies of bacterial chemotaxis receptors. Ligand binding to the receptor causes a piston motion of an α helix in the periplasmic and transmembrane domains, but it is unclear how the signal is then propagated through the cytoplasmic domain to control the activity of the associated kinase CheA. Recent proposals suggest that signaling in the cytoplasmic domain involves opposing changes in dynamics in different subdomains. However, it has been difficult to measure dynamics within the functional system, consisting of extended arrays of receptor complexes with two other proteins, CheA and CheW. We have combined hydrogen exchange mass spectrometry with vesicle template assembly of functional complexes of the receptor cytoplasmic domain to reveal that there are significant signaling-associated changes in exchange, and these changes localize to key regions of the receptor involved in the excitation and adaptation responses. The methylation subdomain exhibits complex changes that include slower hydrogen exchange in complexes in a kinase-activating state, which may be partially consistent with proposals that this subdomain is stabilized in this state. The signaling subdomain exhibits significant protection from hydrogen exchange in complexes in a kinase-activating state, suggesting a tighter and/or larger interaction interface with CheA and CheW in this state. These first measurements of the stability of protein subdomains within functional signaling complexes demonstrate the promise of this approach for measuring functionally important protein dynamics within the various physiologically relevant states of multiprotein complexes. PMID:25420045

Design and development of an international clinical data exchange system: the international layer function of the Dolphin Project

PubMed Central

Zhou, Tian-shu; Chu, Jian; Araki, Kenji; Yoshihara, Hiroyuki

2011-01-01

Objective At present, most clinical data are exchanged between organizations within a regional system. However, people traveling abroad may need to visit a hospital, which would make international exchange of clinical data very useful. Background Since 2007, a collaborative effort to achieve clinical data sharing has been carried out at Zhejiang University in China and Kyoto University and Miyazaki University in Japan; each is running a regional clinical information center. Methods An international layer system named Global Dolphin was constructed with several key services, sharing patients' health information between countries using a medical markup language (MML). The system was piloted with 39 test patients. Results The three regions above have records for 966 000 unique patients, which are available through Global Dolphin. Data exchanged successfully from Japan to China for the 39 study patients include 1001 MML files and 152 images. The MML files contained 197 free text-type paragraphs that needed human translation. Discussion The pilot test in Global Dolphin demonstrates that patient information can be shared across countries through international health data exchange. To achieve cross-border sharing of clinical data, some key issues had to be addressed: establishment of a super directory service across countries; data transformation; and unique one—language translation. Privacy protection was also taken into account. The system is now ready for live use. Conclusion The project demonstrates a means of achieving worldwide accessibility of medical data, by which the integrity and continuity of patients' health information can be maintained. PMID:21571747

HPC Annual Report: Emulytics.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crussell, Jonathan; Boote, Jeffrey W.; Fritz, David Jakob

Networked Information Technology systems play a key role supporting critical government, military, and private computer installations. Many of today's critical infrastructure systems have strong dependencies on secure information exchange among geographically dispersed facilities. As operations become increasingly dependent on the information exchange they also become targets for exploitation. The need to protect data and defend these systems from external attack has become increasingly vital while the nature of the threats has become sophisticated and pervasive making the challenges daunting. Enter Emulytics.

Fostering internationalization: an American-Danish semester-long undergraduate nursing student exchange program.

PubMed

Baernholdt, M; Drake, E; Maron, F; Neymark, K

2013-06-01

This paper describes the development, implementation and evaluation of a semester-long exchange program between two Bachelor of Science in Nursing programs in the USA and Denmark. Nurses globally need to provide culturally sensitive care for an ethnically diverse population. Competencies on how to do so should start in basic nursing programs. A useful strategy is through immersion into another culture through an exchange program. Little is known about successful strategies for two-way or 360° exchange programs between schools from different countries. Guided by experiential learning theory, we developed an exchange program with the objective of enhancing nursing students' cultural competence through knowledge building, attitudes and behaviour development. Lessons learned and implications for educational institutions and policy are discussed. In internationalization of nursing education, an awareness of underlying cultural values regarding nursing competence and taking appropriate action are important for success. Other areas for a successful exchange program include matching of courses or content across schools, clear objectives and evaluation plans. Finally, flexibility and open communication are key components when setting up a 360° exchange program. © 2013 The Authors. International Nursing Review © 2013 International Council of Nurses.

Isotopic Exchange in Porous and Dense Magnesium Borohydride.

PubMed

Zavorotynska, Olena; Deledda, Stefano; Li, Guanqiao; Matsuo, Motoaki; Orimo, Shin-ichi; Hauback, Bjørn C

2015-09-01

Magnesium borohydride (Mg(BH4)2) is one of the most promising complex hydrides presently studied for energy-related applications. Many of its properties depend on the stability of the BH4(-) anion. The BH4(-) stability was investigated with respect to H→D exchange. In situ Raman measurements on high-surface-area porous Mg(BH4 )2 in 0.3 MPa D2 have shown that the isotopic exchange at appreciable rates occurs already at 373 K. This is the lowest exchange temperature observed in stable borohydrides. Gas-solid isotopic exchange follows the BH4(-) +D˙ →BH3D(-) +H˙ mechanism at least at the initial reaction steps. Ex situ deuteration of porous Mg(BH4)2 and its dense-phase polymorph indicates that the intrinsic porosity of the hydride is the key behind the high isotopic exchange rates. It implies that the solid-state H(D) diffusion is considerably slower than the gas-solid H→D exchange reaction at the surface and it is a rate-limiting steps for hydrogen desorption and absorption in Mg(BH4)2. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Exchange Stiffness in Thin-Film Cobalt Alloys

NASA Astrophysics Data System (ADS)

Eyrich, Charles

The exchange stiffness, Aex, is one of the key parameters controlling magnetization reversal in magnetic materials but is very difficult to measure, especially in thin films. We developed a new technique for measuring the exchange stiffness of a magnetic material based on the formation of a spin spiral within two antiferromagnetically coupled ferromagnetic films [1]. Using this method, I was able to measure the exchange stiffness of thin film Co alloyed with Cr, Fe, Ni, Pd, Pt and Ru. The results of this work showed that the rate at which a substituent element reduces the exchange stiffness is not directly related to its effect on the magnetization of the alloy. These measured trends have been understood by combining measurements of element specific magnetic moments obtained using X-ray magnetic circular dichroism (XMCD) and material specific modeling based on density functional theory (DFT) within the local density approximation (LDA). The experimental results also hint at significant reduction of the exchange stiffness at the interface that can account for the difference between our results and those obtained on bulk materials.

Ligand lability and chirality inversion in yb heterobimetallic catalysts.

PubMed

Di Bari, Lorenzo; Lelli, Moreno; Salvadori, Piero

2004-09-20

We have investigated the exchange dynamics between the free and bound ligand in K3[Yb[(R)-binol]3], the most active heterobimetallic lanthanoid catalyst for cyclic imine hydrophosphonylation; we found that the Yb-binol bond is labile. The rate constant for this exchange was determined through NMR saturation transfer experiments. Upon addition of (S)-binaphthol, ligand exchange leads to the formation of a small quantity of heterochiral complexes and, in the presence of a molar excess of (S)-binaphthol, to chirality inversion of the whole complex. This demonstrates that, in contrast to other analogous systems, K3[Yb(binol)3] displays a strong chiral discrimination, with the overwhelming preference for ligands of the same configuration. The lability of Yb-binol bond in THF may suggest a ligand-to-substrate exchange as a key step in the catalytic process.

Quantum key management

DOEpatents

Hughes, Richard John; Thrasher, James Thomas; Nordholt, Jane Elizabeth

2016-11-29

Innovations for quantum key management harness quantum communications to form a cryptography system within a public key infrastructure framework. In example implementations, the quantum key management innovations combine quantum key distribution and a quantum identification protocol with a Merkle signature scheme (using Winternitz one-time digital signatures or other one-time digital signatures, and Merkle hash trees) to constitute a cryptography system. More generally, the quantum key management innovations combine quantum key distribution and a quantum identification protocol with a hash-based signature scheme. This provides a secure way to identify, authenticate, verify, and exchange secret cryptographic keys. Features of the quantum key management innovations further include secure enrollment of users with a registration authority, as well as credential checking and revocation with a certificate authority, where the registration authority and/or certificate authority can be part of the same system as a trusted authority for quantum key distribution.

SeaQuaKE: Sea-optimized Quantum Key Exchange

DTIC Science & Technology

2014-06-01

is led by Applied Communications Sciences under the ONR Free Space Optical Quantum Key Distribution Special Notice (13-SN-0004 under ONRBAA13-001...In addition, we discuss our initial progress towards the free - space quantum channel model and planning for the experimental validation effort. 15...SUBJECT TERMS Quantum communications, free - space optical communications 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as

NCX-DB: a unified resource for integrative analysis of the sodium calcium exchanger super-family.

PubMed

Bode, Katrin; O'Halloran, Damien M

2018-04-13

Na + /Ca 2+ exchangers are low-affinity high-capacity transporters that mediate Ca 2+ extrusion by coupling Ca 2+ efflux to the influx of Na + ions. The Na + /Ca 2+ exchangers form a super-family comprised of three branches each differing in ion-substrate selectivity: Na + /Ca 2+ exchangers (NCX), Na + /Ca 2+ /K + exchangers, and Ca 2+ /cation exchangers. Their primary function is to maintain Ca 2+ homeostasis and play a particularly important role in excitable cells that experience transient Ca 2+ fluxes. Research into the role and activity of Na + /Ca 2+ exchangers has focused extensively on the cardio-vascular system, however, growing evidence suggests that Na + /Ca 2+ exchangers play a key role in neuronal processes such as memory formation, learning, oligodendrocyte differentiation, neuroprotection during brain ischemia and axon guidance. They have also been implicated in pathologies such as Alzheimer's disease, Parkinson's disease, Multiple Sclerosis and Epilepsy, however, a clear understanding of their mechanism during disease is lacking. To date, there has never been a central resource or database for Na + /Ca 2+ exchangers. With clear disease relevance and ever-increasing research on Na + /Ca 2+ exchangers from both model and non-model species, a database that unifies the data on Na + /Ca 2+ exchangers is needed for future research. NCX-DB is a publicly available database with a web interface that enables users to explore various Na + /Ca 2+ exchangers, perform cross-species sequence comparison, identify new exchangers, and stay-up to date with recent literature. NCX-DB is available on the web via an interactive user interface with an intuitive design, which is applicable for the identification and comparison of Na + /Ca 2+ exchanger proteins across diverse species.

Quantum key distribution without the wavefunction

NASA Astrophysics Data System (ADS)

Niestegge, Gerd

A well-known feature of quantum mechanics is the secure exchange of secret bit strings which can then be used as keys to encrypt messages transmitted over any classical communication channel. It is demonstrated that this quantum key distribution allows a much more general and abstract access than commonly thought. The results include some generalizations of the Hilbert space version of quantum key distribution, but are based upon a general nonclassical extension of conditional probability. A special state-independent conditional probability is identified as origin of the superior security of quantum key distribution; this is a purely algebraic property of the quantum logic and represents the transition probability between the outcomes of two consecutive quantum measurements.

Ultrafast spin exchange-coupling torque via photo-excited charge-transfer processes

DOE PAGES

Ma, X.; Fang, F.; Li, Q.; ...

2015-10-28

In this study, optical control of spin is of central importance in the research of ultrafast spintronic devices utilizing spin dynamics at short time scales. Recently developed optical approaches such as ultrafast demagnetization, spin-transfer and spin-orbit torques open new pathways to manipulate spin through its interaction with photon, orbit, charge or phonon. However, these processes are limited by either the long thermal recovery time or the low-temperature requirement. Here we experimentally demonstrate ultrafast coherent spin precession via optical charge-transfer processes in the exchange-coupled Fe/CoO system at room temperature. The efficiency of spin precession excitation is significantly higher and the recoverymore » time of the exchange-coupling torque is much shorter than for the demagnetization procedure, which is desirable for fast switching. The exchange coupling is a key issue in spin valves and tunnelling junctions, and hence our findings will help promote the development of exchange-coupled device concepts for ultrafast coherent spin manipulation.« less

Long-range magnetic interactions and proximity effects in an amorphous exchange-spring magnet

DOE PAGES

Magnus, F.; Brooks-Bartlett, M. E.; Moubah, R.; ...

2016-06-13

Low-dimensional magnetic heterostructures are a key element of spintronics, where magnetic interactions between different materials often define the functionality of devices. Although some interlayer exchange coupling mechanisms are by now well established, the possibility of direct exchange coupling via proximity-induced magnetization through non-magnetic layers is typically ignored due to the presumed short range of such proximity effects. Here we show that magnetic order can be induced throughout a 40-nm-thick amorphous paramagnetic layer through proximity to ferromagnets, mediating both exchange-spring magnet behaviour and exchange bias. Furthermore, Monte Carlo simulations show that nearest-neighbour magnetic interactions fall short in describing the observed effectsmore » and long-range magnetic interactions are needed to capture the extent of the induced magnetization. Lastly, the results highlight the importance of considering the range of interactions in low-dimensional heterostructures and how magnetic proximity effects can be used to obtain new functionality.« less

Analysis of a membrane-based condesate recovery heat exchanger (CRX)

NASA Technical Reports Server (NTRS)

Newbold, D.D.

1993-01-01

The development of a temperature and humidity control system that can remove heat and recover water vapor is key to the development of an Environmental Control and Life Support System (ECLSS). Large quantities of water vapor must be removed from air, and this operation has proven difficult in the absense of gravity. This paper presents the modeling results from a program to develop a novel membrane-based heat exchanger known as the condensate recovery heat exchanger (CRX). This device cools and dehumidifies humid air and simultaneously recovers water-vapor condensate. In this paper, the CRX is described and the results of an analysis of the heat- and mass-transfer characteristics of the device are given.

Living the Golden Rule: Reciprocal Exchanges Among African Americans With Cancer

PubMed Central

Hamilton, Jill B.; Sandelowski, Margarete

2010-01-01

Giving is receiving, and receiving is giving. This is the key finding from interviews conducted with 28 African American women and men with cancer who were active participants in dynamic relationships characterized by both giving and receiving. These participants engaged in reciprocal relationships varying in the number of persons involved, types of resources exchanged, and timing of exchange. Findings suggest the need to reconceptualize social support as caregiving and caregiving as social support. This study also points to the need to redesign intervention studies to be more inclusive of components that allow the elderly in illness-related situations to maintain their status as givers in their social networks. PMID:12756686

IGES, a key interface specification for CAD/CAM systems integration

NASA Technical Reports Server (NTRS)

Smith, B. M.; Wellington, J.

1984-01-01

The Initial Graphics Exchange Specification (IGES) program has focused the efforts of 52 companies on the development and documentation of a means of graphics data base exchange among present day CAD/CAM systems. The project's brief history has seen the evolution of the Specification into preliminary industrial usage marked by public demonstrations of vendor capability, mandatory requests in procurement actions, and a formalization into an American National Standard in September 1981. Recent events have demonstrated intersystem data exchange among seven vendor systems with a total of 30 vendors committing to offer IGES capability. A full range of documentation supports the IGES project and the recently approved IGES Version 2.0 of the Specification.

Co nanoparticles inserted into a porous carbon amorphous matrix: the role of cooling field and temperature on the exchange bias effect.

PubMed

Fernández-García, María Paz; Gorria, Pedro; Sevilla, Marta; Fuertes, Antonio B; Boada, Roberto; Chaboy, Jesús; Aquilanti, Giuliana; Blanco, Jesús A

2011-01-21

We report unusual cooling field dependence of the exchange bias in oxide-coated cobalt nanoparticles embedded within the nanopores of a carbon matrix. The size-distribution of the nanoparticles and the exchange bias coupling observed up to about 200 K between the Co-oxide shell (∼3-4 nm) and the ferromagnetic Co-cores (∼4-6 nm) are the key to understand the magnetic properties of this system. The estimated values of the effective anisotropy constant and saturation magnetization obtained from the fit of the zero-field cooling and field cooling magnetization vs. temperature curves agree quite well with those of the bulk fcc-Co.

Driving Safely into the Future with Applied Technology

DOT National Transportation Integrated Search

2013-06-19

This report highlights key recommendations and noteworthy practices identified at the peer exchange on Introducing Performance Management into the Metropolitan Planning Organization (MPO) Planning Process held on June, 19, 2013 in Bismarck, Nor...

Elucidating the Key Role of a Lewis Base Solvent in the Formation of Perovskite Films Fabricated from the Lewis Adduct Approach.

PubMed

Cao, Xiaobing; Zhi, Lili; Li, Yahui; Fang, Fei; Cui, Xian; Yao, Youwei; Ci, Lijie; Ding, Kongxian; Wei, Jinquan

2017-09-27

High-quality perovskite films can be fabricated from Lewis acid-base adducts through molecule exchange. Substantial work is needed to fully understand the formation mechanism of the perovskite films, which helps to further improve their quality. Here, we study the formation of CH 3 NH 3 PbI 3 perovskite films by introducing some dimethylacetamide into the PbI 2 /N,N-dimethylformamide solution. We reveal that there are three key processes during the formation of perovskite films through the Lewis acid-base adduct approach: molecule intercalation of solvent into the PbI 2 lattice, molecule exchange between the solvent and CH 3 NH 3 I, and dissolution-recrystallization of the perovskite grains during annealing. The Lewis base solvents play multiple functions in the above processes. The properties of the solvent, including Lewis basicity and boiling point, play key roles in forming smooth perovskite films with large grains. We also provide some rules for choosing Lewis base additives to prepare high-quality perovskite films through the Lewis adduct approach.

Modeling bronchial circulation with application to soluble gas exchange: description and sensitivity analysis.

PubMed

Bui, T D; Dabdub, D; George, S C

1998-06-01

The steady-state exchange of inert gases across an in situ canine trachea has recently been shown to be limited equally by diffusion and perfusion over a wide range (0.01-350) of blood solubilities (betablood; ml . ml-1 . atm-1). Hence, we hypothesize that the exchange of ethanol (betablood = 1,756 at 37 degrees C) in the airways depends on the blood flow rate from the bronchial circulation. To test this hypothesis, the dynamics of the bronchial circulation were incorporated into an existing model that describes the simultaneous exchange of heat, water, and a soluble gas in the airways. A detailed sensitivity analysis of key model parameters was performed by using the method of Latin hypercube sampling. The model accurately predicted a previously reported experimental exhalation profile of ethanol (R2 = 0.991) as well as the end-exhalation airstream temperature (34.6 degrees C). The model predicts that 27, 29, and 44% of exhaled ethanol in a single exhalation are derived from the tissues of the mucosa and submucosa, the bronchial circulation, and the tissue exterior to the submucosa (which would include the pulmonary circulation), respectively. Although the concentration of ethanol in the bronchial capillary decreased during inspiration, the three key model outputs (end-exhaled ethanol concentration, the slope of phase III, and end-exhaled temperature) were all statistically insensitive (P > 0.05) to the parameters describing the bronchial circulation. In contrast, the model outputs were all sensitive (P < 0.05) to the thickness of tissue separating the core body conditions from the bronchial smooth muscle. We conclude that both the bronchial circulation and the pulmonary circulation impact soluble gas exchange when the entire conducting airway tree is considered.

Federation for a Secure Enterprise

DTIC Science & Technology

2016-09-10

12 October 2005 e. RFC Internet X.509 Public Key Infrastructure: Certification Path Building, 2005 f. Public Key Cryptography Standard, PKCS #1...v2.2: RSA Cryptography Standard, RSA Laboratories, October 27, 2012 g. PKCS#12 format PKCS #12 v1.0: Personal Information Exchange Syntax Standard, RSA...ClientHello padding extension, 2015-02-17 f. Elliptic Curve Cryptography (ECC) Cipher Suites for Transport Layer Security (TLS) Versions 1.2 and Earlier

Investigation of the key determinants of Asian nurses' quality of life.

PubMed

Makabe, Sachiko; Kowitlawakul, Yanika; Nurumal, Mohd Said; Takagai, Junko; Wichaikhum, Orn-Anong; Wangmo, Neyzang; Yap, Suk Foon; Kunaviktikul, Wipada; Komatsu, Junko; Shirakawa, Hideko; Kimura, Yutaka; Asanuma, Yoshihiro

2018-06-01

The study aimed to compare nurses' quality of life and investigate key determinants among Asian countries with different economic status. A cross-sectional survey was conducted across five Asian countries (Japan, Singapore, Malaysia, Thailand, and Bhutan). Quality of life (WHOQOL-BREF), job stress (National Institute of Occupational Safety and Health questionnaire), and demographic data were assessed. Stepwise multivariate linear regression analysis was performed to identify the key determinants of quality of life. Participants were 3,829 nurses (response rate: 82%) with a mean age of 33 ± 10 yr and majority were women (92%). Regarding quality of life, Bhutan yielded the highest scores, followed by Malaysia, Thailand, Singapore, and Japan, and these results were statistically significant. The key determinants that were significantly related to quality of life were "stress coping ability," "life satisfaction," "Japan," "social support," "job stress," and "Singapore" (adjusted R 2 =0.46). In conclusion, nurses' quality of life differs across Asian countries and is not linked to the country's economic development. To maintain a good quality of life for nurses, an international exchange program like international nursing conferences for work environment and staff coping strategies is recommended to broaden institution' minds and share experiences and exchange views to be able to realize their own problems and discover global solutions to them.

Developing formal asset management plans

DOT National Transportation Integrated Search

2014-06-01

This report highlights key recommendations and best practices identified at the peer exchange on Transportation Asset Management Plans (TAMP), held on February 5 and 6, 2014, in Columbia, South Carolina. This event was sponsored by the Transportation...

Human factors engineering: the next challenge.

PubMed

Durand-Viel, Denys

2004-10-01

This fictional exchange between a General Manager, a Research and Development Officer and a Regulatory Affairs Manager after a near incident with a recently launched device explains how human factors engineering is the key to design success.

Marrying Up by Marrying Down: Status Exchange between Social Origin and Education in the United States

PubMed Central

Schwartz, Christine R.; Zeng, Zhen; Xie, Yu

2016-01-01

Intermarriage plays a key role in stratification systems. Spousal resemblance reinforces social boundaries within and across generations, and the rules of intermarriage govern the ways that social mobility may occur. We examine intermarriage across social origin and education boundaries in the United States using data from the 1968–2013 Panel Study of Income Dynamics. Our evidence points to a pattern of status exchange—that is, persons with high education from modest backgrounds tend to marry those with lower education from more privileged backgrounds. Our study contributes to an active methodological debate by pinpointing the conditions under which the results pivot from evidence against exchange to evidence for exchange and advances theory by showing that the rules of exchange are more consistent with the notion of diminishing marginal utility than the more general theory of compensating differentials. PMID:28066795

Atomic sites and stability of Cs+ captured within zeolitic nanocavities

PubMed Central

Yoshida, Kaname; Toyoura, Kazuaki; Matsunaga, Katsuyuki; Nakahira, Atsushi; Kurata, Hiroki; Ikuhara, Yumi H.; Sasaki, Yukichi

2013-01-01

Zeolites have potential application as ion-exchangers, catalysts and molecular sieves. Zeolites are once again drawing attention in Japan as stable adsorbents and solidification materials of fission products, such as 137Cs+ from damaged nuclear-power plants. Although there is a long history of scientific studies on the crystal structures and ion-exchange properties of zeolites for practical application, there are still open questions, at the atomic-level, on the physical and chemical origins of selective ion-exchange abilities of different cations and detailed atomic structures of exchanged cations inside the nanoscale cavities of zeolites. Here, the precise locations of Cs+ ions captured within A-type zeolite were analyzed using high-resolution electron microscopy. Together with theoretical calculations, the stable positions of absorbed Cs+ ions in the nanocavities are identified, and the bonding environment within the zeolitic framework is revealed to be a key factor that influences the locations of absorbed cations. PMID:23949184

Water exchange in manganese-based water-oxidizing catalysts in photosynthetic systems: from the water-oxidizing complex in photosystem II to nano-sized manganese oxides.

PubMed

Najafpour, Mohammad Mahdi; Isaloo, Mohsen Abbasi; Eaton-Rye, Julian J; Tomo, Tatsuya; Nishihara, Hiroshi; Satoh, Kimiyuki; Carpentier, Robert; Shen, Jian-Ren; Allakhverdiev, Suleyman I

2014-09-01

The water-oxidizing complex (WOC), also known as the oxygen-evolving complex (OEC), of photosystem II in oxygenic photosynthetic organisms efficiently catalyzes water oxidation. It is, therefore, responsible for the presence of oxygen in the Earth's atmosphere. The WOC is a manganese-calcium (Mn₄CaO₅(H₂O)₄) cluster housed in a protein complex. In this review, we focus on water exchange chemistry of metal hydrates and discuss the mechanisms and factors affecting this chemical process. Further, water exchange rates for both the biological cofactor and synthetic manganese water splitting are discussed. The importance of fully unveiling the water exchange mechanism to understand the chemistry of water oxidation is also emphasized here. This article is part of a special issue entitled: photosynthesis research for sustainability: keys to produce clean energy. Copyright © 2014 Elsevier B.V. All rights reserved.

Connecting Medical Records: An Evaluation of Benefits and Challenges for Primary Care Practices.

PubMed

Compeau, Deborah Ruth; Terry, Amanda

2017-06-30

Implementation of systems to support health information sharing has lagged other areas of healthcare IT, yet offers a strong possibility for benefit.  Clinical acceptance is a key limiting factor in health IT adoption. To assess the benefits and challenges experienced by clinicians using a custom-developed health information exchange system, and to show how perceptions of benefits and challenges influence perceptions of productivity and care-related outcomes. We used a mixed methods design with two phases. First, we conducted interviews with stakeholders who were familiar with the health information exchange system to inform the development of a measure of benefits and challenges of the use of this system. Second, using this measure we conducted a survey of current and former users of the health information exchange system using a modified Dillman method. 105 current and former users completed the survey. The results showed information quality, ease of completing tasks and clinical process improvement as key benefits that reduced workload and improved patient care.  Challenges related to system reliability, quality of reports and service quality increased workload and decreased impact on care, though the effect of the challenges was smaller than that of the benefits.  Even very limited health information exchange capabilities can improve outcomes for primary care users.  Improving perceptions of benefits may be even more important the removing challenges to use, though it is likely that a threshold of quality must be achieved for this to be true.

Communication: xDH double hybrid functionals can be qualitatively incorrect for non-equilibrium geometries: Dipole moment inversion and barriers to radical-radical association using XYG3 and XYGJ-OS

NASA Astrophysics Data System (ADS)

Hait, Diptarka; Head-Gordon, Martin

2018-05-01

Double hybrid (DH) density functionals are amongst the most accurate density functional approximations developed so far, largely due to the incorporation of correlation effects from unoccupied orbitals via second order perturbation theory (PT2). The xDH family of DH functionals calculate energy directly from orbitals optimized by a lower level approach like B3LYP, without self-consistent optimization. XYG3 and XYGJ-OS are two widely used xDH functionals that are known to be quite accurate at equilibrium geometries. Here, we show that the XYG3 and XYGJ-OS functionals can be ill behaved for stretched bonds well beyond the Coulson-Fischer point, predicting unphysical dipole moments and humps in potential energy curves for some simple systems like the hydrogen fluoride molecule. Numerical experiments and analysis show that these failures are not due to PT2. Instead, a large mismatch at stretched bond-lengths between the reference B3LYP orbitals and the optimized orbitals associated with the non-PT2 part of XYG3 leads to an unphysically large non-Hellman-Feynman contribution to first order properties like forces and electron densities.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Yan-Ming; Su, Ying; Li, Jia

Highlights: Black-Right-Pointing-Pointer NHE protect against intracellular hydrogen overload. Black-Right-Pointing-Pointer NHE protect {beta}-cells against strong acidification. Black-Right-Pointing-Pointer NHE inhibitors improve myocardial ischemia and reperfusion. -- Abstract: Micro- and macrovascular complications are the main cause of morbidity and mortality in diabetes mellitus. The Na{sup +}/H{sup +} exchanger (NHE) is a family of proteins which exchange Na{sup +} for H{sup +} according to their concentration gradients in an electroneutral manner. The exchanger also plays a key role in several other cellular functions including proliferation, differentiation, apoptosis, migration, and cytoskeletal organization. Since not much is known on the relationship between NHE and diabetes mellitus,more » this review outlines the contribution of NHE to chronic complications of diabetes mellitus, such as diabetic nephropathy; diabetic cardiomyopathy.« less

Enabling global exchange of groundwater data: GroundWaterML2 (GWML2)

NASA Astrophysics Data System (ADS)

Brodaric, Boyan; Boisvert, Eric; Chery, Laurence; Dahlhaus, Peter; Grellet, Sylvain; Kmoch, Alexander; Létourneau, François; Lucido, Jessica; Simons, Bruce; Wagner, Bernhard

2018-05-01

GWML2 is an international standard for the online exchange of groundwater data that addresses the problem of data heterogeneity. This problem makes groundwater data hard to find and use because the data are diversely structured and fragmented into numerous data silos. Overcoming data heterogeneity requires a common data format; however, until the development of GWML2, an appropriate international standard has been lacking. GWML2 represents key hydrogeological entities such as aquifers and water wells, as well as related measurements and groundwater flows. It is developed and tested by an international consortium of groundwater data providers from North America, Europe, and Australasia, and facilitates many forms of data exchange, information representation, and the development of online web portals and tools.

Local antiferromagnetic exchange and collaborative Fermi surface as key ingredients of high temperature superconductors

PubMed Central

Hu, Jiangping; Ding, Hong

2012-01-01

Cuprates, ferropnictides and ferrochalcogenides are three classes of unconventional high temperature superconductors, who share similar phase diagrams in which superconductivity develops after a magnetic order is suppressed, suggesting a strong interplay between superconductivity and magnetism, although the exact picture of this interplay remains elusive. Here we show that there is a direct bridge connecting antiferromagnetic exchange interactions determined in the parent compounds of these materials to the superconducting gap functions observed in the corresponding superconducting materials: in all high temperature superconductors, the Fermi surface topology matches the form factor of the pairing symmetry favored by local magnetic exchange interactions. We suggest that this match offers a principle guide to search for new high temperature superconductors. PMID:22536479

Student experiences with an international public health exchange project.

PubMed

Critchley, Kim A; Richardson, Eileen; Aarts, Clara; Campbell, Barbara; Hemmingway, Ann; Koskinen, Liisa; Mitchell, Maureen P; Nordstrom, Pam

2009-01-01

With growing interconnectivity of healthcare systems worldwide and increased immigration, inappropriate cultural and role assumptions are often seen when cultures clash within a country or when there is practice across country boundaries in times of disaster and during international travel. To increase students' multicultural awareness and work experiences abroad, the authors describe a 7-school, 5-country international student exchange project. The authors also share the students' evaluations of their experiences as they are challenged to erase boundaries and embrace nursing across countries. Participating faculty describe the process, challenges, and keys to success found in creating and living this international project. Students involved in the exchange process evaluate the learning opportunities and challenges and the joy of coming together as newfound colleagues and friends.

2011 peer exchange : final report.

DOT National Transportation Integrated Search

2011-05-01

Research and development are key to safe and efficient transportation systems in our country. They have played a vital role in the advancements that have led to our current transportation system. Federal regulation (23 CRF 420 Subpart B) establishes ...

Process-based upscaling of surface-atmosphere exchange

NASA Astrophysics Data System (ADS)

Keenan, T. F.; Prentice, I. C.; Canadell, J.; Williams, C. A.; Wang, H.; Raupach, M. R.; Collatz, G. J.; Davis, T.; Stocker, B.; Evans, B. J.

2015-12-01

Empirical upscaling techniques such as machine learning and data-mining have proven invaluable tools for the global scaling of disparate observations of surface-atmosphere exchange, but are not based on a theoretical understanding of the key processes involved. This makes spatial and temporal extrapolation outside of the training domain difficult at best. There is therefore a clear need for the incorporation of knowledge of ecosystem function, in combination with the strength of data mining. Here, we present such an approach. We describe a novel diagnostic process-based model of global photosynthesis and ecosystem respiration, which is directly informed by a variety of global datasets relevant to ecosystem state and function. We use the model framework to estimate global carbon cycling both spatially and temporally, with a specific focus on the mechanisms responsible for long-term change. Our results show the importance of incorporating process knowledge into upscaling approaches, and highlight the effect of key processes on the terrestrial carbon cycle.

Harnessing Private-Sector Innovation to Improve Health Insurance Exchanges

PubMed Central

Gresenz, Carole Roan; Hoch, Emily; Eibner, Christine; Rudin, Robert S.; Mattke, Soeren

2016-01-01

Abstract Overhauling the individual health insurance market—including through the creation of health insurance exchanges—was a key component of the Patient Protection and Affordable Care Act's multidimensional approach to addressing the long-standing problem of the uninsured in the United States. Despite succeeding in enrolling millions of Americans, the exchanges still face several challenges, including poor consumer experience, high operational and development costs, and incomplete market penetration. In light of these challenges, analysts considered a different model for the exchanges—privately facilitated exchanges—which could address these challenges and deepen the Affordable Care Act's impact. In this model, the government retains control over sovereign exchange functions but allows the private sector to assume responsibility for more-peripheral exchange functions, such as developing and sustaining exchange websites. Although private-sector entities have already undertaken exchange-related functions on a limited basis, privately facilitated exchanges could conceivably relieve the government of its responsibility for front-end website operations and consumer decision-support functions entirely. A shift to privately facilitated exchanges could improve the consumer experience, increase enrollment, and lower costs for state and federal governments. A move to such a model requires, nonetheless, managing its risks, such as reduced consumer protection, increased consumer confusion, and the possible lack of a viable revenue base for privately facilitated exchanges, especially in less populous states. On net, the benefits are large enough and the risks sufficiently manageable to seriously consider such a shift. This paper provides background information and more detail on the analysts' assessment. PMID:28083414

Setting an Upper Limit on Gas Exchange Through Sea-Spray

NASA Astrophysics Data System (ADS)

Vlahos, P.; Monahan, E. C.; Andreas, E. L.

2016-02-01

Air-sea gas exchange parameterization is critical to understanding both climate forcing and feedbacks and is key in biogeochemistry cycles. Models based on wind speed have provided empirical estimates of gas exchange that are useful though it is likely that at high wind speeds of over 10 m/s there are important gas exchange parameters including bubbles and sea spray that have not been well constrained. Here we address the sea-spray component of gas exchange at these high wind speeds to set sn upper boundary condition for the gas exchange of the six model gases including; nobel gases helium, neon and argon, diatomic gases nitrogen and oxygen and finally, the more complex gas carbon dioxide. Estimates are based on the spray generation function of Andreas and Monahan and the gases are tested under three scenarios including 100 percent saturation and complete droplet evaporation, 100 percent saturation and a more realistic scenario in which a fraction of droplets evaporate completely, a fraction evaporate to some degree and a fraction returns to the water side without significant evaporation. Finally the latter scenario is applied to representative under saturated concentrations of the gases.

Quantum key distribution in a multi-user network at gigahertz clock rates

NASA Astrophysics Data System (ADS)

Fernandez, Veronica; Gordon, Karen J.; Collins, Robert J.; Townsend, Paul D.; Cova, Sergio D.; Rech, Ivan; Buller, Gerald S.

2005-07-01

In recent years quantum information research has lead to the discovery of a number of remarkable new paradigms for information processing and communication. These developments include quantum cryptography schemes that offer unconditionally secure information transport guaranteed by quantum-mechanical laws. Such potentially disruptive security technologies could be of high strategic and economic value in the future. Two major issues confronting researchers in this field are the transmission range (typically <100km) and the key exchange rate, which can be as low as a few bits per second at long optical fiber distances. This paper describes further research of an approach to significantly enhance the key exchange rate in an optical fiber system at distances in the range of 1-20km. We will present results on a number of application scenarios, including point-to-point links and multi-user networks. Quantum key distribution systems have been developed, which use standard telecommunications optical fiber, and which are capable of operating at clock rates of up to 2GHz. They implement a polarization-encoded version of the B92 protocol and employ vertical-cavity surface-emitting lasers with emission wavelengths of 850 nm as weak coherent light sources, as well as silicon single-photon avalanche diodes as the single photon detectors. The point-to-point quantum key distribution system exhibited a quantum bit error rate of 1.4%, and an estimated net bit rate greater than 100,000 bits-1 for a 4.2 km transmission range.

Very Few Substitutions in a Germ Line Antibody Are Required To Initiate Significant Domain Exchange ▿

PubMed Central

Huber, Michael; Le, Khoa M.; Doores, Katie J.; Fulton, Zara; Stanfield, Robyn L.; Wilson, Ian A.; Burton, Dennis R.

2010-01-01

2G12 is a broadly neutralizing anti-HIV-1 monoclonal human IgG1 antibody reactive with a high-mannose glycan cluster on the surface of glycoprotein gp120. A key feature of this very highly mutated antibody is domain exchange of the heavy-chain variable region (VH) with the VH of the adjacent Fab of the same immunoglobulin, which assembles a multivalent binding interface composed of two primary binding sites in close proximity. A non-germ line-encoded proline in the elbow between VH and CH1 and an extensive network of hydrophobic interactions in the VH/VH′ interface have been proposed to be crucial for domain exchange. To investigate the origins of domain exchange, a germ line version of 2G12 that behaves as a conventional antibody was engineered. Substitution of 5 to 7 residues for those of the wild type produced a significant fraction of domain-exchanged molecules, with no evidence of equilibrium between domain-exchanged and conventional forms. Two substitutions not previously implicated, AH14 and EH75, are the most crucial for domain exchange, together with IH19 at the VH/VH′ interface and PH113 in the elbow region. Structural modeling gave clues as to why these residues are essential for domain exchange. The demonstration that domain exchange can be initiated by a small number of substitutions in a germ line antibody suggests that the evolution of a domain-exchanged antibody response in vivo may be more readily achieved than considered to date. PMID:20702640

Guaranteeing Spoof-Resilient Multi-Robot Networks

DTIC Science & Technology

2016-02-12

key-distribution. Our core contribution is a novel al- gorithm implemented on commercial Wi - Fi radios that can “sense” spoofers using the physics of...encrypted key exchange, but rather a commercial Wi - Fi card and software to implement our so- lution. Our virtual sensor leverages the rich physical...cheap commodity Wi - Fi radios, unlike hardware-based solutions [46, 48]. (3) It is robust to client mobility and power-scaling at- tacks. Finally, our

An Analysis of Error Reconciliation Protocols for use in Quantum Key Distribution

DTIC Science & Technology

2012-02-01

offers another alternative for exchanging a symmetric key without compromising security. Quantum cryptography is the use of quantum mechanics to... quantum money), and, more significantly for our purposes here, a method for the transmission of two or three messages in such a way that reading...well as two channels. A quantum channel is used to communicate qubits (photons), and it is assumed that only active eavesdropping may take place on

A student's analysis of the Moi University-Linköping University exchange programme.

PubMed

Mwenda, A S

2012-11-01

Introduction : Moi University College of Health Sciences was established in 1989. It is comprised of the schools of medicine, nursing, public health and dentistry. Since its inception, the college has been in collaboration with Linköping University in Sweden. This collaboration has taken the form of student and staff exchanges, as well as infrastructure and library improvements. This study was carried out to analyse the exchange programme and highlight some of the strengths that the exchange programme brings to the students' academic experience. Methods : A qualitative cross-sectional survey was conducted among the students who participated in the elective/exchange programme in the years 2009, 2010 and 2011. Self-administered questionnaires were completed by the participants. Additional data were obtained from the recommendations and conclusions from the reports that the students wrote after their participation in the exchange programme. Focus group discussions and key informant interviews were also carried out. Results : A total of 46 students participated in the exchange programme: 27 from Moi University and 19 from Linköping University. The disciplines of students reflected the undergraduate courses offered by these universities. The exchange programme's strengths were exposing students to new cultural settings, different healthcare system organisation and influencing future academic and personal lives, as well as making education global. The main challenge facing the exchange programme was language. Discussion : This study shows the exchange programme as a strong pillar of the medical education curriculum, enabling students to get a global perspective on their education, while exposing them to significant cultural and healthcare organisation diversity. There is a need to expand the collaboration so that more students have the opportunity to experience the overseas exchange programme.

An absolute measure for a key currency

NASA Astrophysics Data System (ADS)

Oya, Shunsuke; Aihara, Kazuyuki; Hirata, Yoshito

It is generally considered that the US dollar and the euro are the key currencies in the world and in Europe, respectively. However, there is no absolute general measure for a key currency. Here, we investigate the 24-hour periodicity of foreign exchange markets using a recurrence plot, and define an absolute measure for a key currency based on the strength of the periodicity. Moreover, we analyze the time evolution of this measure. The results show that the credibility of the US dollar has not decreased significantly since the Lehman shock, when the Lehman Brothers bankrupted and influenced the economic markets, and has increased even relatively better than that of the euro and that of the Japanese yen.

Field demonstration of a continuous-variable quantum key distribution network.

PubMed

Huang, Duan; Huang, Peng; Li, Huasheng; Wang, Tao; Zhou, Yingming; Zeng, Guihua

2016-08-01

We report on what we believe is the first field implementation of a continuous-variable quantum key distribution (CV-QKD) network with point-to-point configuration. Four QKD nodes are deployed on standard communication infrastructures connected with commercial telecom optical fiber. Reliable key exchange is achieved in the wavelength-division-multiplexing CV-QKD network. The impact of a complex and volatile field environment on the excess noise is investigated, since excess noise controlling and reduction is arguably the major issue pertaining to distance and the secure key rate. We confirm the applicability and verify the maturity of the CV-QKD network in a metropolitan area, thus paving the way for a next-generation global secure communication network.

SAIDE: A Semi-Automated Interface for Hydrogen/Deuterium Exchange Mass Spectrometry.

PubMed

Villar, Maria T; Miller, Danny E; Fenton, Aron W; Artigues, Antonio

2010-01-01

Deuterium/hydrogen exchange in combination with mass spectrometry (DH MS) is a sensitive technique for detection of changes in protein conformation and dynamics. Since temperature, pH and timing control are the key elements for reliable and efficient measurement of hydrogen/deuterium content in proteins and peptides, we have developed a small, semiautomatic interface for deuterium exchange that interfaces the HPLC pumps with a mass spectrometer. This interface is relatively inexpensive to build, and provides efficient temperature and timing control in all stages of enzyme digestion, HPLC separation and mass analysis of the resulting peptides. We have tested this system with a series of standard tryptic peptides reconstituted in a solvent containing increasing concentration of deuterium. Our results demonstrate the use of this interface results in minimal loss of deuterium due to back exchange during HPLC desalting and separation. For peptides reconstituted in a buffer containing 100% deuterium, and assuming that all amide linkages have exchanged hydrogen with deuterium, the maximum loss of deuterium content is only 17% of the label, indicating the loss of only one deuterium molecule per peptide.

SAIDE: A Semi-Automated Interface for Hydrogen/Deuterium Exchange Mass Spectrometry

PubMed Central

Villar, Maria T.; Miller, Danny E.; Fenton, Aron W.; Artigues, Antonio

2011-01-01

Deuterium/hydrogen exchange in combination with mass spectrometry (DH MS) is a sensitive technique for detection of changes in protein conformation and dynamics. Since temperature, pH and timing control are the key elements for reliable and efficient measurement of hydrogen/deuterium content in proteins and peptides, we have developed a small, semiautomatic interface for deuterium exchange that interfaces the HPLC pumps with a mass spectrometer. This interface is relatively inexpensive to build, and provides efficient temperature and timing control in all stages of enzyme digestion, HPLC separation and mass analysis of the resulting peptides. We have tested this system with a series of standard tryptic peptides reconstituted in a solvent containing increasing concentration of deuterium. Our results demonstrate the use of this interface results in minimal loss of deuterium due to back exchange during HPLC desalting and separation. For peptides reconstituted in a buffer containing 100% deuterium, and assuming that all amide linkages have exchanged hydrogen with deuterium, the maximum loss of deuterium content is only 17% of the label, indicating the loss of only one deuterium molecule per peptide. PMID:25309638

Overview of the mechanisms that could explain the 'Boundary Exchange' at the land-ocean contact.

PubMed

Jeandel, Catherine

2016-11-28

Land to ocean transfer of material largely controls the chemical composition of seawater and the global element cycles. Oceanic isotopic budgets of chemical species, macro- and micronutrients (e.g. Nd, Sr, Si, Mg, Zn, Mo and Ni) have revealed an imbalance between their sources and sinks. Radiogenic isotope budgets underlined the importance of taking into account continental margins as a source of elements to oceans. They also highlighted that the net land-ocean inputs of chemical species probably result from particle-dissolved exchange processes, named 'Boundary Exchange'. Yet, locations where 'Boundary Exchange' occurs are not clearly identified and reviewed here: discharge of huge amount of freshly weathered particles at the river mouths, submarine weathering of deposited sediments along the margins, submarine groundwater discharges and subterranean estuaries. As a whole, we conclude that all of them might contribute to 'Boundary Exchange'. Highlighting their specific roles and the processes at play is a key scientific issue for the second half of GEOTRACES.This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'. © 2016 The Author(s).

Porous PVDF/PANI ion-exchange membrane (IEM) modified by polyvinylpyrrolidone (PVP) and lithium chloride in the application of membrane capacitive deionisation (MCDI).

PubMed

Zhang, Yiming; Zhang, Wei; Cházaro-Ruiz, Luis F

2018-05-01

In this work, polyvinylidene fluoride (PVDF)/polyaniline (PANI) heterogeneous anion-exchange membranes filled with pore-forming agents polyvinylpyrrolidone (PVP) and lithium chloride were prepared by the solution-casting technique using the solvent 1-methyl-2-pyrrolidone (NMP) and a two-step phase inversion procedure. Key properties of the as-prepared membranes, such as hydrophilicity, water content, ion exchange capacity, fixed ion concentration, conductivity and transport number were examined and compared between membranes in different conditions. The pore-forming hydrophilic additives PVP and lithium chloride to the casting solution appeared to improve the ion-exchange membranes (IEMs) by increasing the conductivity, transport number and hydrophilicity. The effects of increasing membrane drying time on the porosity of the as-prepared membranes were found to lower membrane porosity by reducing membrane water content. However, pore-forming agents were found to be able to stabilise membrane transport number with different drying times. As-prepared PVDF/PANI anion-exchange membrane with pore-forming agent is demonstrated to be a more efficient candidate for water purification (e.g. desalination) and other industrial applications.

Molecular dissection of nutrient exchange at the insect-microbial interface.

PubMed

Douglas, Angela E

2014-10-01

Genome research is transforming our understanding of nutrient exchange between insects and intracellular bacteria. A key characteristic of these bacteria is their small genome size and gene content. Their fastidious and inflexible nutritional requirements are met by multiple metabolites from the insect host cell. Although the bacteria have generally retained genes coding the synthesis of nutrients required by the insect, some apparently critical genes have been lost, and compensated for by shared metabolic pathways with the insect host or supplementary bacteria with complementary metabolic capabilities. Copyright © 2014 Elsevier Inc. All rights reserved.

Community Connections for I-10: A TPCB Peer Exchange Event

DOT National Transportation Integrated Search

2018-03-13

This report highlights key recommendations and noteworthy practices identified at Community Connections for I-10 held on March 13-14, 2018 in Baton Rouge, Louisiana. This event was sponsored by the Transportation Planning Capacity Building (TPC...

Experimental quantum key distribution with finite-key security analysis for noisy channels.

PubMed

Bacco, Davide; Canale, Matteo; Laurenti, Nicola; Vallone, Giuseppe; Villoresi, Paolo

2013-01-01

In quantum key distribution implementations, each session is typically chosen long enough so that the secret key rate approaches its asymptotic limit. However, this choice may be constrained by the physical scenario, as in the perspective use with satellites, where the passage of one terminal over the other is restricted to a few minutes. Here we demonstrate experimentally the extraction of secure keys leveraging an optimal design of the prepare-and-measure scheme, according to recent finite-key theoretical tight bounds. The experiment is performed in different channel conditions, and assuming two distinct attack models: individual attacks or general quantum attacks. The request on the number of exchanged qubits is then obtained as a function of the key size and of the ambient quantum bit error rate. The results indicate that viable conditions for effective symmetric, and even one-time-pad, cryptography are achievable.

A New Three Dimensional Based Key Generation Technique in AVK

NASA Astrophysics Data System (ADS)

Banerjee, Subhasish; Dutta, Manash Pratim; Bhunia, Chandan Tilak

2017-08-01

In modern era, ensuring high order security becomes one and only objective of computer networks. From the last few decades, many researchers have given their contributions to achieve the secrecy over the communication channel. In achieving perfect security, Shannon had done the pioneer work on perfect secret theorem and illustrated that secrecy of the shared information can be maintained if the key becomes variable in nature instead of static one. In this regard, a key generation technique has been proposed where the key can be changed every time whenever a new block of data needs to be exchanged. In our scheme, the keys not only vary in bit sequences but also in size. The experimental study is also included in this article to prove the correctness and effectiveness of our proposed technique.

Dynamics of neural cryptography

NASA Astrophysics Data System (ADS)

Ruttor, Andreas; Kinzel, Wolfgang; Kanter, Ido

2007-05-01

Synchronization of neural networks has been used for public channel protocols in cryptography. In the case of tree parity machines the dynamics of both bidirectional synchronization and unidirectional learning is driven by attractive and repulsive stochastic forces. Thus it can be described well by a random walk model for the overlap between participating neural networks. For that purpose transition probabilities and scaling laws for the step sizes are derived analytically. Both these calculations as well as numerical simulations show that bidirectional interaction leads to full synchronization on average. In contrast, successful learning is only possible by means of fluctuations. Consequently, synchronization is much faster than learning, which is essential for the security of the neural key-exchange protocol. However, this qualitative difference between bidirectional and unidirectional interaction vanishes if tree parity machines with more than three hidden units are used, so that those neural networks are not suitable for neural cryptography. In addition, the effective number of keys which can be generated by the neural key-exchange protocol is calculated using the entropy of the weight distribution. As this quantity increases exponentially with the system size, brute-force attacks on neural cryptography can easily be made unfeasible.

Dynamics of neural cryptography.

PubMed

Ruttor, Andreas; Kinzel, Wolfgang; Kanter, Ido

2007-05-01

Synchronization of neural networks has been used for public channel protocols in cryptography. In the case of tree parity machines the dynamics of both bidirectional synchronization and unidirectional learning is driven by attractive and repulsive stochastic forces. Thus it can be described well by a random walk model for the overlap between participating neural networks. For that purpose transition probabilities and scaling laws for the step sizes are derived analytically. Both these calculations as well as numerical simulations show that bidirectional interaction leads to full synchronization on average. In contrast, successful learning is only possible by means of fluctuations. Consequently, synchronization is much faster than learning, which is essential for the security of the neural key-exchange protocol. However, this qualitative difference between bidirectional and unidirectional interaction vanishes if tree parity machines with more than three hidden units are used, so that those neural networks are not suitable for neural cryptography. In addition, the effective number of keys which can be generated by the neural key-exchange protocol is calculated using the entropy of the weight distribution. As this quantity increases exponentially with the system size, brute-force attacks on neural cryptography can easily be made unfeasible.

Dynamics of neural cryptography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruttor, Andreas; Kinzel, Wolfgang; Kanter, Ido

2007-05-15

Synchronization of neural networks has been used for public channel protocols in cryptography. In the case of tree parity machines the dynamics of both bidirectional synchronization and unidirectional learning is driven by attractive and repulsive stochastic forces. Thus it can be described well by a random walk model for the overlap between participating neural networks. For that purpose transition probabilities and scaling laws for the step sizes are derived analytically. Both these calculations as well as numerical simulations show that bidirectional interaction leads to full synchronization on average. In contrast, successful learning is only possible by means of fluctuations. Consequently,more » synchronization is much faster than learning, which is essential for the security of the neural key-exchange protocol. However, this qualitative difference between bidirectional and unidirectional interaction vanishes if tree parity machines with more than three hidden units are used, so that those neural networks are not suitable for neural cryptography. In addition, the effective number of keys which can be generated by the neural key-exchange protocol is calculated using the entropy of the weight distribution. As this quantity increases exponentially with the system size, brute-force attacks on neural cryptography can easily be made unfeasible.« less

Study of the Quantum Channel between Earth and Space for Satellite Quantum Communications

NASA Astrophysics Data System (ADS)

Bonato, Cristian; Tomaello, Andrea; da Deppo, Vania; Naletto, Giapiero; Villoresi, Paolo

In this work there are studied the conditions for the effective quantum communications between a terminal on Earth and the other onboard of an orbiter. The quantum key distribution between a LEO satellite and a ground station is studied in particular. The effect of the propagation over long distances as well as the background during day or night is modeled, compared and discussed in the context of key generation and exchange.

Investigation of the key determinants of Asian nurses’ quality of life

PubMed Central

MAKABE, Sachiko; KOWITLAWAKUL, Yanika; NURUMAL, Mohd Said; TAKAGAI, Junko; WICHAIKHUM, Orn-Anong; WANGMO, Neyzang; YAP, Suk Foon; KUNAVIKTIKUL, Wipada; KOMATSU, Junko; SHIRAKAWA, Hideko; KIMURA, Yutaka; ASANUMA, Yoshihiro

2018-01-01

The study aimed to compare nurses’ quality of life and investigate key determinants among Asian countries with different economic status. A cross-sectional survey was conducted across five Asian countries (Japan, Singapore, Malaysia, Thailand, and Bhutan). Quality of life (WHOQOL-BREF), job stress (National Institute of Occupational Safety and Health questionnaire), and demographic data were assessed. Stepwise multivariate linear regression analysis was performed to identify the key determinants of quality of life. Participants were 3,829 nurses (response rate: 82%) with a mean age of 33 ± 10 yr and majority were women (92%). Regarding quality of life, Bhutan yielded the highest scores, followed by Malaysia, Thailand, Singapore, and Japan, and these results were statistically significant. The key determinants that were significantly related to quality of life were “stress coping ability,” “life satisfaction,” “Japan,” “social support,” “job stress,” and “Singapore” (adjusted R2=0.46). In conclusion, nurses’ quality of life differs across Asian countries and is not linked to the country’s economic development. To maintain a good quality of life for nurses, an international exchange program like international nursing conferences for work environment and staff coping strategies is recommended to broaden institution’ minds and share experiences and exchange views to be able to realize their own problems and discover global solutions to them. PMID:29491251

Updating Rhode Island’s Strategic Highway Safety Plan (SHSP) : an RSPCB Peer Exchange

DOT National Transportation Integrated Search

2012-03-01

In January 2012, Rhode Island kicked off its Strategic Highway Safety Plan (SHSP) update with a leadership committee meeting where key safety stakeholders presented an overview of Rhode Islands accomplishments since initial SHSP approval in 2007. ...

Alabama Department of Transportation : research and development 2011 peer exchange.

DOT National Transportation Integrated Search

2011-05-01

Research and development are key to safe and efficient transportation systems in our country. They have played a vital role in the advancements that have led to our current transportation system. Federal regulation (23 CRF 420 Subpart B) establishes ...

DEVELOPING INDICATORS OF SALT MARSH HEALTH

EPA Science Inventory

We relate plant zonation in salt marshes to key ecosystem services such as erosion control and wildlife habitat. Ten salt marshes in Narragansett Bay, with similar geological bedrock and sea exchange, were identified to examine plant zonation. Sub-watersheds adjacent to the salt ...

Interoperability and models for exchange of data between information systems in public administration

NASA Astrophysics Data System (ADS)

Glavev, Victor

2016-12-01

The types of software applications used by public administrations can be divided in three main groups: document management systems, record management systems and business process systems. Each one of them generates outputs that can be used as input data to the others. This is the main reason that requires exchange of data between these three groups and well defined models that should be followed. There are also many other reasons that will be discussed in the paper. Interoperability is a key aspect when those models are implemented, especially when there are different manufactures of systems in the area of software applications used by public authorities. The report includes examples of implementation of models for exchange of data between software systems deployed in one of the biggest administration in Bulgaria.

Martian stable isotopes: volatile evolution, climate change and exobiological implications

NASA Technical Reports Server (NTRS)

Jakosky, B. M.

1999-01-01

Measurements of the ratios of stable isotopes in the martian atmosphere and crust provide fundamental information about the evolution of the martian volatile and climate system. Current best estimates of the isotope ratios indicate that there has been substantial loss of gases to space and exchange of gases between the atmosphere and the crust throughout geologic time; exchange may have occurred through circulation of water in hydrothermal systems. Processes of volatile evolution and exchange will fractionate the isotopes in a manner that complicates the possible interpretation of isotopic data in terms of any fractionation that may have been caused by martian biota, and must be understood first. Key measurements are suggested that will enhance our understanding of the non-biological fractionation of the isotopes and of the evolution of the martian volatile system.

Practical quantum key distribution protocol without monitoring signal disturbance.

PubMed

Sasaki, Toshihiko; Yamamoto, Yoshihisa; Koashi, Masato

2014-05-22

Quantum cryptography exploits the fundamental laws of quantum mechanics to provide a secure way to exchange private information. Such an exchange requires a common random bit sequence, called a key, to be shared secretly between the sender and the receiver. The basic idea behind quantum key distribution (QKD) has widely been understood as the property that any attempt to distinguish encoded quantum states causes a disturbance in the signal. As a result, implementation of a QKD protocol involves an estimation of the experimental parameters influenced by the eavesdropper's intervention, which is achieved by randomly sampling the signal. If the estimation of many parameters with high precision is required, the portion of the signal that is sacrificed increases, thus decreasing the efficiency of the protocol. Here we propose a QKD protocol based on an entirely different principle. The sender encodes a bit sequence onto non-orthogonal quantum states and the receiver randomly dictates how a single bit should be calculated from the sequence. The eavesdropper, who is unable to learn the whole of the sequence, cannot guess the bit value correctly. An achievable rate of secure key distribution is calculated by considering complementary choices between quantum measurements of two conjugate observables. We found that a practical implementation using a laser pulse train achieves a key rate comparable to a decoy-state QKD protocol, an often-used technique for lasers. It also has a better tolerance of bit errors and of finite-sized-key effects. We anticipate that this finding will give new insight into how the probabilistic nature of quantum mechanics can be related to secure communication, and will facilitate the simple and efficient use of conventional lasers for QKD.

On the improvement of neural cryptography using erroneous transmitted information with error prediction.

PubMed

Allam, Ahmed M; Abbas, Hazem M

2010-12-01

Neural cryptography deals with the problem of "key exchange" between two neural networks using the mutual learning concept. The two networks exchange their outputs (in bits) and the key between the two communicating parties is eventually represented in the final learned weights, when the two networks are said to be synchronized. Security of neural synchronization is put at risk if an attacker is capable of synchronizing with any of the two parties during the training process. Therefore, diminishing the probability of such a threat improves the reliability of exchanging the output bits through a public channel. The synchronization with feedback algorithm is one of the existing algorithms that enhances the security of neural cryptography. This paper proposes three new algorithms to enhance the mutual learning process. They mainly depend on disrupting the attacker confidence in the exchanged outputs and input patterns during training. The first algorithm is called "Do not Trust My Partner" (DTMP), which relies on one party sending erroneous output bits, with the other party being capable of predicting and correcting this error. The second algorithm is called "Synchronization with Common Secret Feedback" (SCSFB), where inputs are kept partially secret and the attacker has to train its network on input patterns that are different from the training sets used by the communicating parties. The third algorithm is a hybrid technique combining the features of the DTMP and SCSFB. The proposed approaches are shown to outperform the synchronization with feedback algorithm in the time needed for the parties to synchronize.

Evaluating Status Change of Soil Potassium from Path Model

PubMed Central

He, Wenming; Chen, Fang

2013-01-01

The purpose of this study is to determine critical environmental parameters of soil K availability and to quantify those contributors by using a proposed path model. In this study, plot experiments were designed into different treatments, and soil samples were collected and further analyzed in laboratory to investigate soil properties influence on soil potassium forms (water soluble K, exchangeable K, non-exchangeable K). Furthermore, path analysis based on proposed path model was carried out to evaluate the relationship between potassium forms and soil properties. Research findings were achieved as followings. Firstly, key direct factors were soil S, ratio of sodium-potassium (Na/K), the chemical index of alteration (CIA), Soil Organic Matter in soil solution (SOM), Na and total nitrogen in soil solution (TN), and key indirect factors were Carbonate (CO3), Mg, pH, Na, S, and SOM. Secondly, path model can effectively determine direction and quantities of potassium status changes between Exchangeable potassium (eK), Non-exchangeable potassium (neK) and water-soluble potassium (wsK) under influences of specific environmental parameters. In reversible equilibrium state of , K balance state was inclined to be moved into β and χ directions in treatments of potassium shortage. However in reversible equilibrium of , K balance state was inclined to be moved into θ and λ directions in treatments of water shortage. Results showed that the proposed path model was able to quantitatively disclose moving direction of K status and quantify its equilibrium threshold. It provided a theoretical and practical basis for scientific and effective fertilization in agricultural plants growth. PMID:24204659

Health information exchange policies of 11 diverse health systems and the associated impact on volume of exchange.

PubMed

Downing, N Lance; Adler-Milstein, Julia; Palma, Jonathan P; Lane, Steven; Eisenberg, Matthew; Sharp, Christopher; Longhurst, Christopher A

2017-01-01

Provider organizations increasingly have the ability to exchange patient health information electronically. Organizational health information exchange (HIE) policy decisions can impact the extent to which external information is readily available to providers, but this relationship has not been well studied. Our objective was to examine the relationship between electronic exchange of patient health information across organizations and organizational HIE policy decisions. We focused on 2 key decisions: whether to automatically search for information from other organizations and whether to require HIE-specific patient consent. We conducted a retrospective time series analysis of the effect of automatic querying and the patient consent requirement on the monthly volume of clinical summaries exchanged. We could not assess degree of use or usefulness of summaries, organizational decision-making processes, or generalizability to other vendors. Between 2013 and 2015, clinical summary exchange volume increased by 1349% across 11 organizations. Nine of the 11 systems were set up to enable auto-querying, and auto-querying was associated with a significant increase in the monthly rate of exchange (P = .006 for change in trend). Seven of the 11 organizations did not require patient consent specifically for HIE, and these organizations experienced a greater increase in volume of exchange over time compared to organizations that required consent. Automatic querying and limited consent requirements are organizational HIE policy decisions that impact the volume of exchange, and ultimately the information available to providers to support optimal care. Future efforts to ensure effective HIE may need to explicitly address these factors. © The Author 2016. Published by Oxford University Press on behalf of the American Medical Informatics Association.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Wei; Krishnan, Kannan M.

Exchange bias has been investigated for more than half a century and several insightful reviews, published around the year 2000, have already summarized many key experimental and theoretical aspects related to this phenomenon. Since then, due to developments in thin-film fabrication and sophisticated characterization methods, exchange bias continues to show substantial advances; in particular, recent studies on epitaxial systems, which is the focus of this review, allow many long-standing mysteries of exchange bias to be unambiguously resolved. The advantage of epitaxial samples lies in the well-defined interface structures, larger coherence lengths, and competing magnetic anisotropies, which are often negligible inmore » polycrystalline samples. Beginning with a discussion of the microscopic spin properties at the ferromagnetic/antiferromagnetic interface, we correlate the details of spin lattices with phenomenological anisotropies, and finally connect the two by introducing realistic measurement approaches and models. We conclude by providing a brief perspective on the future of exchange bias and related studies in the context of the rapidly evolving interest in antiferromagnetic spintronics.« less

The impact of lower sea-ice extent on Arctic greenhouse-gas exchange

USGS Publications Warehouse

Parmentier, Frans-Jan W.; Christensen, Torben R.; Sørensen, Lise Lotte; Rysgaard, Søren; McGuire, A. David; Miller, Paul A.; Walker, Donald A.

2013-01-01

In September 2012, Arctic sea-ice extent plummeted to a new record low: two times lower than the 1979–2000 average. Often, record lows in sea-ice cover are hailed as an example of climate change impacts in the Arctic. Less apparent, however, are the implications of reduced sea-ice cover in the Arctic Ocean for marine–atmosphere CO2 exchange. Sea-ice decline has been connected to increasing air temperatures at high latitudes. Temperature is a key controlling factor in the terrestrial exchange of CO2 and methane, and therefore the greenhouse-gas balance of the Arctic. Despite the large potential for feedbacks, many studies do not connect the diminishing sea-ice extent with changes in the interaction of the marine and terrestrial Arctic with the atmosphere. In this Review, we assess how current understanding of the Arctic Ocean and high-latitude ecosystems can be used to predict the impact of a lower sea-ice cover on Arctic greenhouse-gas exchange.

Impact of Health Disclosure Laws on Health Information Exchanges

PubMed Central

Adjerid, Idris; Padman, Rema

2011-01-01

Health information exchanges (HIEs) are expected to facilitate data sharing between healthcare entities, thereby improving the efficiency and quality of care. Privacy concerns have been consistently cited as one of the primary challenges to HIE formation and success. Currently, it is unclear how privacy laws – in particular, legislation restricting the disclosure of health records – have shaped the development of HIEs. This preliminary study explores the landscape of state-level health privacy legislation and examines the impact of variations in such privacy and confidentiality laws on the progress of HIEs. We found that states with stronger privacy laws, limiting the disclosure of health information, had significantly more HIEs exchanging data and had fewer failed HIEs. We suggest that this counterintuitive finding may be explained by the more subtle benefits of such laws, such as increased confidence and trust of participants in an exchange. Other key contributors to this work are Alessandro Acquisti, Rahul Telang, and Julia Adler-Milstein PMID:22195054

Ground Source Heat Pump Sub-Slab Heat Exchange Loop Performance in a Cold Climate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mittereder, N.; Poerschke, A.

2013-11-01

This report presents a cold-climate project that examines an alternative approach to ground source heat pump (GSHP) ground loop design. The innovative ground loop design is an attempt to reduce the installed cost of the ground loop heat exchange portion of the system by containing the entire ground loop within the excavated location beneath the basement slab. Prior to the installation and operation of the sub-slab heat exchanger, energy modeling using TRNSYS software and concurrent design efforts were performed to determine the size and orientation of the system. One key parameter in the design is the installation of the GSHPmore » in a low-load home, which considerably reduces the needed capacity of the ground loop heat exchanger. This report analyzes data from two cooling seasons and one heating season. Upon completion of the monitoring phase, measurements revealed that the initial TRNSYS simulated horizontal sub-slab ground loop heat exchanger fluid temperatures and heat transfer rates differed from the measured values. To determine the cause of this discrepancy, an updated model was developed utilizing a new TRNSYS subroutine for simulating sub-slab heat exchangers. Measurements of fluid temperature, soil temperature, and heat transfer were used to validate the updated model.« less

Structural outline of the detailed mechanism for elongation factor Ts-mediated guanine nucleotide exchange on elongation factor Tu.

PubMed

Thirup, Søren S; Van, Lan Bich; Nielsen, Tine K; Knudsen, Charlotte R

2015-07-01

Translation elongation factor EF-Tu belongs to the superfamily of guanine-nucleotide binding proteins, which play key cellular roles as regulatory switches. All G-proteins require activation via exchange of GDP for GTP to carry out their respective tasks. Often, guanine-nucleotide exchange factors are essential to this process. During translation, EF-Tu:GTP transports aminoacylated tRNA to the ribosome. GTP is hydrolyzed during this process, and subsequent reactivation of EF-Tu is catalyzed by EF-Ts. The reaction path of guanine-nucleotide exchange is structurally poorly defined for EF-Tu and EF-Ts. We have determined the crystal structures of the following reaction intermediates: two structures of EF-Tu:GDP:EF-Ts (2.2 and 1.8Å resolution), EF-Tu:PO4:EF-Ts (1.9Å resolution), EF-Tu:GDPNP:EF-Ts (2.2Å resolution) and EF-Tu:GDPNP:pulvomycin:Mg(2+):EF-Ts (3.5Å resolution). These structures provide snapshots throughout the entire exchange reaction and suggest a mechanism for the release of EF-Tu in its GTP conformation. An inferred sequence of events during the exchange reaction is presented. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Long-term corneal endothelial cell changes in pediatric intraocular lens reposition and exchange cases.

PubMed

Wang, Yan; Wu, Mingxing; Zhu, Liyuan; Liu, Yizhi

2012-04-01

To evaluate long-term corneal endothelial cell changes of intraocular lens (IOL) reposition and exchange in children. State key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China In this retrospective study, all IOL reposition and exchange procedures performed in patients under 14 years old between January 1999 and April 2009 were included. Follow-up outcomes included corneal endothelial cell density, hexagonality, coefficient of variance, average cell size. IOL reposition procedures in 12 eyes (12 cases) (reposition group, RPG), and IOL exchanges in eight eyes (eight cases) (exchange group, EXG) were performed because of IOL pupillary capture or IOL dislocation. Median of follow-up was 44.5 months in RPG and 66.2 months in EXG. The density of corneal endothelial cells in RPG (2,053 ± 493/mm(2)) and EXG (2,100 ± 758/mm(2)) was significantly decreased in comparison to the control eyes (3,116 ± 335/mm(2)). Hexagonality of corneal endothelial cells and coefficient of variance showed no difference among the control group, RPG and EXG (P > 0.05). The density of corneal endothelial cells was conspicuously decreased after IOL reposition or exchange procedures in childhood cases. Longer follow-up must be conducted in these cases.

Selective permeation of moisture and VOCs through polymer membranes used in total heat exchangers for indoor air ventilation.

PubMed

Zhang, L-Z; Zhang, X-R; Miao, Q-Z; Pei, L-X

2012-08-01

Fresh air ventilation is central to indoor environmental control. Total heat exchangers can be key equipment for energy conservation in ventilation. Membranes have been used for total heat exchangers for more than a decade. Much effort has been spent to achieve water vapor permeability of various membranes; however, relatively little attention has been paid to the selectivity of moisture compared with volatile organic compounds (VOCs) through such membranes. In this investigation, the most commonly used membranes, both hydrophilic and hydrophobic ones, are tested for their permeability for moisture and five VOCs (acetic acid, formaldehyde, acetaldehyde, toluene, and ethane). The selectivity of moisture vs. VOCs in these membranes is then evaluated. With a solution-diffusion model, the solubility and diffusivity of moisture and VOCs in these membranes are calculated. The resulting data could provide some reference for future material selection. Total heat exchangers are important equipment for fresh air ventilation with energy conservation. However, their implications for indoor air quality in terms of volatile organic compound permeation have not been known. The data in this article help us to clarify the impacts on indoor VOC levels of membrane-based heat exchangers. Guidelines for material selection can be obtained for future use total heat exchangers for building ventilation. © 2011 John Wiley & Sons A/S.

Improved key-rate bounds for practical decoy-state quantum-key-distribution systems

NASA Astrophysics Data System (ADS)

Zhang, Zhen; Zhao, Qi; Razavi, Mohsen; Ma, Xiongfeng

2017-01-01

The decoy-state scheme is the most widely implemented quantum-key-distribution protocol in practice. In order to account for the finite-size key effects on the achievable secret key generation rate, a rigorous statistical fluctuation analysis is required. Originally, a heuristic Gaussian-approximation technique was used for this purpose, which, despite its analytical convenience, was not sufficiently rigorous. The fluctuation analysis has recently been made rigorous by using the Chernoff bound. There is a considerable gap, however, between the key-rate bounds obtained from these techniques and that obtained from the Gaussian assumption. Here we develop a tighter bound for the decoy-state method, which yields a smaller failure probability. This improvement results in a higher key rate and increases the maximum distance over which secure key exchange is possible. By optimizing the system parameters, our simulation results show that our method almost closes the gap between the two previously proposed techniques and achieves a performance similar to that of conventional Gaussian approximations.

Have You Explored Leasing as a Vehicle for Equipping Your Center?

ERIC Educational Resources Information Center

Smith, Dennis G.

1987-01-01

Explains advantages of leasing child care center equipment to improve cash flow and conserve capital for other center needs. Discusses what equipment can be leased and lists key negotiating points for lease contracts. Gives information about Exchange Leasing, Inc. (NH)

CLAHRCs in practice: combined knowledge transfer and exchange strategies, cultural change, and experimentation.

PubMed

Soper, Bryony; Yaqub, Ohid; Hinrichs, Saba; Marjanovich, Sonja; Drabble, Samuel; Hanney, Stephen; Nolte, Ellen

2013-10-01

The nine NIHR CLAHRCs are collaborations between universities and local NHS organizations that seek to improve patient outcomes through the conduct and application of applied health research. The theoretical and practical context within which the CLAHRCs were set up was characterized by a considerable degree of uncertainty, and the CLAHRCs were established as a natural experiment. We adopted a formative and emergent evaluation approach. Drawing on in-depth, multi-method case studies of two CLAHRCs we explored how they pursued their remit by supporting efforts to increase the relevance and use of health research, and building relationships. Both CLAHRCs: strengthened local networks and relationships; built capacity in their local academic and NHS communities to undertake and use research that meets the needs of the service; developed research and implementation methodologies; and added to understanding of the complex relation between research and implementation. There was evidence of impact of CLAHRC projects on health and social care services. Informed by the literature on implementing collaborative research initiatives, knowledge transfer and exchange and cultural change, some key lessons can be drawn. The CLAHRCs pursued a strategy that can be categorized as one of flexible comprehensiveness; i.e. their programmes have been flexible and responsive and they have used a range of approaches that seek to match the diverse aspects of the complex issues they face. Key features include their work on combining a range of knowledge transfer and exchange strategies, their efforts to promote cultural change, and the freedom to experiment, learn and adapt. Although the CLAHRCs do not, by themselves, have the remit or resources to bring about wholesale service improvement in health care, they do have features that would allow them to play a key role in some of the wider initiatives that encourage innovation.

UTM Data Working Group Demonstration 1: Final Report

NASA Technical Reports Server (NTRS)

Rios, Joseph L.; Mulfinger, Daniel G.; Smith, Irene S.; Venkatesan, Priya; Smith, David R.; Baskaran, Vijayakumar; Wang, Leo

2017-01-01

This document summarizes activities defining and executing the first demonstration of the NASA-FAA Research Transition Team (RTT) Data Exchange and Information Architecture (DEIA) working group (DWG). The demonstration focused on testing the interactions between two key components in the future UAS Traffic Management (UTM) System through a collaborative and distributed simulation of key scenarios. The summary incorporates written feedback from each of the participants in the demonstration. In addition to reporting the activities, this report also provides some insight into future steps of this working group.

A Scenario-Based Protocol Checker for Public-Key Authentication Scheme

NASA Astrophysics Data System (ADS)

Saito, Takamichi

Security protocol provides communication security for the internet. One of the important features of it is authentication with key exchange. Its correctness is a requirement of the whole of the communication security. In this paper, we introduce three attack models realized as their attack scenarios, and provide an authentication-protocol checker for applying three attack-scenarios based on the models. We also utilize it to check two popular security protocols: Secure SHell (SSH) and Secure Socket Layer/Transport Layer Security (SSL/TLS).

An application of different dioids in public key cryptography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Durcheva, Mariana I., E-mail: mdurcheva66@gmail.com

2014-11-18

Dioids provide a natural framework for analyzing a broad class of discrete event dynamical systems such as the design and analysis of bus and railway timetables, scheduling of high-throughput industrial processes, solution of combinatorial optimization problems, the analysis and improvement of flow systems in communication networks. They have appeared in several branches of mathematics such as functional analysis, optimization, stochastic systems and dynamic programming, tropical geometry, fuzzy logic. In this paper we show how to involve dioids in public key cryptography. The main goal is to create key – exchange protocols based on dioids. Additionally the digital signature scheme ismore » presented.« less

All about Eve: Secret Sharing using Quantum Effects

NASA Technical Reports Server (NTRS)

Jackson, Deborah J.

2005-01-01

This document discusses the nature of light (including classical light and photons), encryption, quantum key distribution (QKD), light polarization and beamsplitters and their application to information communication. A quantum of light represents the smallest possible subdivision of radiant energy (light) and is called a photon. The QKD key generation sequence is outlined including the receiver broadcasting the initial signal indicating reception availability, timing pulses from the sender to provide reference for gated detection of photons, the sender generating photons through random polarization while the receiver detects photons with random polarization and communicating via data link to mutually establish random keys. The QKD network vision includes inter-SATCOM, point-to-point Gnd Fiber and SATCOM-fiber nodes. QKD offers an unconditionally secure method of exchanging encryption keys. Ongoing research will focus on how to increase the key generation rate.

[History of acupuncture in Iran].

PubMed

Bai, Xinghua

2015-10-01

Iran is the neighbor of western China, and is a key transport junction on ancient Silk Road. The medical communication between China and Iran dates back to the 10th century, however, according to current evidences, it is indicated that acupuncture has not been introduced to Iran until the early 1970s. Unfortunately over the last 40 years, the acupuncture in Iran has not presented great development. The history of acupuncture development in Iran implies that geographical advantage and personnel exchanges are not essential to the international exchange of acupuncture, while language and cultural background may hinder the spread of acupuncture in foreign countries.

Copper(I)-catalyzed substitution reactions of propargylic amines: importance of C(sp)-C(sp3) bond cleavage in generation of iminium intermediates.

PubMed

Sugiishi, Tsuyuka; Kimura, Akifumi; Nakamura, Hiroyuki

2010-04-21

Substitution reactions of propargylic amines proceed in the presence of copper(I) catalysts. Mechanistic studies showed that C(sp)-C(sp(3)) bond cleavage assisted by nitrogen lone-pair electrons is essential for the reaction, and the resulting iminium intermediates undergo amine exchange, aldehyde exchange, and alkyne addition reactions. Because iminium intermediates are key to aldehyde-alkyne-amine (A(3)) coupling reactions, this transformation is effective not only for reconstruction of propargylic amines but also for chiral induction of racemic compounds in the presence of chiral catalysts.

Aqueous-Processed, High-Capacity Electrodes for Membrane Capacitive Deionization.

PubMed

Jain, Amit; Kim, Jun; Owoseni, Oluwaseye M; Weathers, Cierra; Caña, Daniel; Zuo, Kuichang; Walker, W Shane; Li, Qilin; Verduzco, Rafael

2018-05-15

Membrane capacitive deionization (MCDI) is a low-cost technology for desalination. Typically, MCDI electrodes are fabricated using a slurry of nanoparticles in an organic solvent along with polyvinylidene fluoride (PVDF) polymeric binder. Recent studies of the environmental impact of CDI have pointed to the organic solvents used in the fabrication of CDI electrodes as key contributors to the overall environmental impact of the technology. Here, we report a scalable, aqueous processing approach to prepare MCDI electrodes using water-soluble polymer poly(vinyl alcohol) (PVA) as a binder and ion-exchange polymer. Electrodes are prepared by depositing aqueous slurry of activated carbon and PVA binder followed by coating with a thin layer of PVA-based cation- or anion-exchange polymer. When coated with ion-exchange layers, the PVA-bound electrodes exhibit salt adsorption capacities up to 14.4 mg/g and charge efficiencies up to 86.3%, higher than typically achieved for activated carbon electrodes with a hydrophobic polymer binder and ion-exchange membranes (5-13 mg/g). Furthermore, when paired with low-resistance commercial ion-exchange membranes, salt adsorption capacities exceed 18 mg/g. Our overall approach demonstrates a simple, environmentally friendly, cost-effective, and scalable method for the fabrication of high-capacity MCDI electrodes.

Cognitive Adaptations for n-person Exchange: The Evolutionary Roots of Organizational Behavior.

PubMed

Tooby, John; Cosmides, Leda; Price, Michael E

2006-03-01

Organizations are composed of stable, predominantly cooperative interactions or n -person exchanges. Humans have been engaging in n -person exchanges for a great enough period of evolutionary time that we appear to have evolved a distinct constellation of species-typical mechanisms specialized to solve the adaptive problems posed by this form of social interaction. These mechanisms appear to have been evolutionarily elaborated out of the cognitive infrastructure that initially evolved for dyadic exchange. Key adaptive problems that these mechanisms are designed to solve include coordination among individuals, and defense against exploitation by free riders. Multi-individual cooperation could not have been maintained over evolutionary time if free riders reliably benefited more than contributors to collective enterprises, and so outcompeted them. As a result, humans evolved mechanisms that implement an aversion to exploitation by free riding, and a strategy of conditional cooperation, supplemented by punitive sentiment towards free riders. Because of the design of these mechanisms, how free riding is treated is a central determinant of the survival and health of cooperative organizations. The mapping of the evolved psychology of n -party exchange cooperation may contribute to the construction of a principled theoretical foundation for the understanding of human behavior in organizations.

Development and Testing of a Refractory Millimeter-Wave Absorbent Heat Exchanger

NASA Technical Reports Server (NTRS)

Lambot, Thomas; Myrabo, Leik; Murakami, David; Parkin, Kevin

2014-01-01

Central to the Millimeter-Wave Thermal Launch System (MTLS) is the millimeter-wave absorbent heat exchanger. We have developed metallic and ceramic variants, with the key challenge being the millimeter-wave absorbent coatings for each. The ceramic heat exchanger came to fruition first, demonstrating for the first time 1800 K peak surface temperatures under illumination by a 110 GHz Gaussian beam. Absorption efficiencies of up to 80 are calculated for mullite heat exchanger tubes and up to 50 are calculated for alumina tubes. These are compared with estimates based on stratified layer and finite element analyses. The problem of how to connect the 1800 K end of the ceramic tubes to a graphite outlet manifold and nozzle is solved by press fitting, or by threading the ends of the ceramic tubes and screwing them into place. The problem of how to connect the ceramic tubes to a metallic or nylon inlet pipe is solved by using soft compliant PTFE and PVC tubes that accommodate thermal deformations of the ceramic tubes during startup and operation. We show the resulting heat exchangers in static tests using argon and helium as propellants.

Concerted ligand exchange and the roles of counter anions in the reversible structural switching of crystalline peptide metallo-macrocycles.

PubMed

Miyake, Ryosuke; Shionoya, Mitsuhiko

2014-06-02

To understand reversible structural switching in crystalline materials, we studied the mechanism of reversible crystal-to-crystal transformation of a tetranuclear Ni(II) macrocycle consisting of artificial β-dipeptides. On the basis of detailed structural analyses and thermodynamic measurements made in a comparison of pseudo-isostructural crystals (NO3 and BF4 salts), we herein discuss how ligand-exchange reactions take place in the crystal due to changes in water content and temperature. Observations of the structural transformation of NO3 salt indicated that a pseudo crystalline phase transformation takes place through concerted ligand-exchange reactions at the four Ni(II) centers of the macrocycle with hydrogen bond switching. A mechanism for this ligand exchange was supported by IR spectroscopy. Thermodynamic measurements suggested that the favorable compensation relationship of the enthalpy changes due to water uptake and structural changes are keys to the reversible structural transformation. On the basis of a comparison with the pseudo-isostructural crystals, it is apparent that the crystal packing structure and the types of counter anions are important factors for facilitating reversible ligand exchange with single crystallinity.

Cognitive Adaptations for n-person Exchange: The Evolutionary Roots of Organizational Behavior

PubMed Central

Tooby, John; Cosmides, Leda; Price, Michael E.

2013-01-01

Organizations are composed of stable, predominantly cooperative interactions or n-person exchanges. Humans have been engaging in n-person exchanges for a great enough period of evolutionary time that we appear to have evolved a distinct constellation of species-typical mechanisms specialized to solve the adaptive problems posed by this form of social interaction. These mechanisms appear to have been evolutionarily elaborated out of the cognitive infrastructure that initially evolved for dyadic exchange. Key adaptive problems that these mechanisms are designed to solve include coordination among individuals, and defense against exploitation by free riders. Multi-individual cooperation could not have been maintained over evolutionary time if free riders reliably benefited more than contributors to collective enterprises, and so outcompeted them. As a result, humans evolved mechanisms that implement an aversion to exploitation by free riding, and a strategy of conditional cooperation, supplemented by punitive sentiment towards free riders. Because of the design of these mechanisms, how free riding is treated is a central determinant of the survival and health of cooperative organizations. The mapping of the evolved psychology of n-party exchange cooperation may contribute to the construction of a principled theoretical foundation for the understanding of human behavior in organizations. PMID:23814325

Structural Landscape of the Proline-Rich Domain of Sos1 Nucleotide Exchange Factor

PubMed Central

McDonald, Caleb B.; Bhat, Vikas; Kurouski, Dmitry; Mikles, David C.; Deegan, Brian J.; Seldeen, Kenneth L.; Lednev, Igor K.; Farooq, Amjad

2013-01-01

Despite its key role in mediating a plethora of cellular signaling cascades pertinent to health and disease, little is known about the structural landscape of the proline-rich (PR) domain of Sos1 guanine nucleotide exchange factor. Herein, using a battery of biophysical tools, we provide evidence that the PR domain of Sos1 is structurally disordered and adopts an extended random coil-like conformation in solution. Of particular interest is the observation that while chemical denaturation of PR domain results in the formation of a significant amount of polyproline II (PPII) helices, it has little or negligible effect on its overall size as measured by its hydrodynamic radius. Our data also show that the PR domain displays a highly dynamic conformational basin in agreement with the knowledge that the intrinsically unstructured proteins rapidly interconvert between an ensemble of conformations. Collectively, our study provides new insights into the conformational equilibrium of a key signaling molecule with important consequences on its physiological function. PMID:23528987

An Agent-Based Modeling Framework and Application for the Generic Nuclear Fuel Cycle

NASA Astrophysics Data System (ADS)

Gidden, Matthew J.

Key components of a novel methodology and implementation of an agent-based, dynamic nuclear fuel cycle simulator, Cyclus , are presented. The nuclear fuel cycle is a complex, physics-dependent supply chain. To date, existing dynamic simulators have not treated constrained fuel supply, time-dependent, isotopic-quality based demand, or fuel fungibility particularly well. Utilizing an agent-based methodology that incorporates sophisticated graph theory and operations research techniques can overcome these deficiencies. This work describes a simulation kernel and agents that interact with it, highlighting the Dynamic Resource Exchange (DRE), the supply-demand framework at the heart of the kernel. The key agent-DRE interaction mechanisms are described, which enable complex entity interaction through the use of physics and socio-economic models. The translation of an exchange instance to a variant of the Multicommodity Transportation Problem, which can be solved feasibly or optimally, follows. An extensive investigation of solution performance and fidelity is then presented. Finally, recommendations for future users of Cyclus and the DRE are provided.

Analysis of an Attenuator Artifact in an Experimental Attack by Gunn-Allison-Abbott Against the Kirchhoff-Law-Johnson-Noise (KLJN) Secure Key Exchange System

NASA Astrophysics Data System (ADS)

Kish, Laszlo B.; Gingl, Zoltan; Mingesz, Robert; Vadai, Gergely; Smulko, Janusz; Granqvist, Claes-Göran

2015-12-01

A recent paper by Gunn-Allison-Abbott (GAA) [L. J. Gunn et al., Scientific Reports 4 (2014) 6461] argued that the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange system could experience a severe information leak. Here we refute their results and demonstrate that GAA's arguments ensue from a serious design flaw in their system. Specifically, an attenuator broke the single Kirchhoff-loop into two coupled loops, which is an incorrect operation since the single loop is essential for the security in the KLJN system, and hence GAA's asserted information leak is trivial. Another consequence is that a fully defended KLJN system would not be able to function due to its built-in current-comparison defense against active (invasive) attacks. In this paper we crack GAA's scheme via an elementary current-comparison attack which yields negligible error probability for Eve even without averaging over the correlation time of the noise.

The Yeast Nuclear Pore Complex and Transport Through It

PubMed Central

Aitchison, John D.; Rout, Michael P.

2012-01-01

Exchange of macromolecules between the nucleus and cytoplasm is a key regulatory event in the expression of a cell’s genome. This exchange requires a dedicated transport system: (1) nuclear pore complexes (NPCs), embedded in the nuclear envelope and composed of proteins termed nucleoporins (or “Nups”), and (2) nuclear transport factors that recognize the cargoes to be transported and ferry them across the NPCs. This transport is regulated at multiple levels, and the NPC itself also plays a key regulatory role in gene expression by influencing nuclear architecture and acting as a point of control for various nuclear processes. Here we summarize how the yeast Saccharomyces has been used extensively as a model system to understand the fundamental and highly conserved features of this transport system, revealing the structure and function of the NPC; the NPC’s role in the regulation of gene expression; and the interactions of transport factors with their cargoes, regulatory factors, and specific nucleoporins. PMID:22419078

Surface Connectivity and Interocean Exchanges From Drifter-Based Transition Matrices

NASA Astrophysics Data System (ADS)

McAdam, Ronan; van Sebille, Erik

2018-01-01

Global surface transport in the ocean can be represented by using the observed trajectories of drifters to calculate probability distribution functions. The oceanographic applications of the Markov Chain approach to modeling include tracking of floating debris and water masses, globally and on yearly-to-centennial time scales. Here we analyze the error inherent with mapping trajectories onto a grid and the consequences for ocean transport modeling and detection of accumulation structures. A sensitivity analysis of Markov Chain parameters is performed in an idealized Stommel gyre and western boundary current as well as with observed ocean drifters, complementing previous studies on widespread floating debris accumulation. Focusing on two key areas of interocean exchange—the Agulhas system and the North Atlantic intergyre transport barrier—we assess the capacity of the Markov Chain methodology to detect surface connectivity and dynamic transport barriers. Finally, we extend the methodology's functionality to separate the geostrophic and nongeostrophic contributions to interocean exchange in these key regions.

GUI implementation of image encryption and decryption using Open CV-Python script on secured TFTP protocol

NASA Astrophysics Data System (ADS)

Reddy, K. Rasool; Rao, Ch. Madhava

2018-04-01

Currently safety is one of the primary concerns in the transmission of images due to increasing the use of images within the industrial applications. So it's necessary to secure the image facts from unauthorized individuals. There are various strategies are investigated to secure the facts. In that encryption is certainly one of maximum distinguished method. This paper gives a sophisticated Rijndael (AES) algorithm to shield the facts from unauthorized humans. Here Exponential Key Change (EKE) concept is also introduced to exchange the key between client and server. The things are exchange in a network among client and server through a simple protocol is known as Trivial File Transfer Protocol (TFTP). This protocol is used mainly in embedded servers to transfer the data and also provide protection to the data if protection capabilities are integrated. In this paper, implementing a GUI environment for image encryption and decryption. All these experiments carried out on Linux environment the usage of Open CV-Python script.

High-performance light-emitting diodes based on carbene-metal-amides

NASA Astrophysics Data System (ADS)

Di, Dawei; Romanov, Alexander S.; Yang, Le; Richter, Johannes M.; Rivett, Jasmine P. H.; Jones, Saul; Thomas, Tudor H.; Abdi Jalebi, Mojtaba; Friend, Richard H.; Linnolahti, Mikko; Bochmann, Manfred; Credgington, Dan

2017-04-01

Organic light-emitting diodes (OLEDs) promise highly efficient lighting and display technologies. We introduce a new class of linear donor-bridge-acceptor light-emitting molecules, which enable solution-processed OLEDs with near-100% internal quantum efficiency at high brightness. Key to this performance is their rapid and efficient utilization of triplet states. Using time-resolved spectroscopy, we establish that luminescence via triplets occurs within 350 nanoseconds at ambient temperature, after reverse intersystem crossing to singlets. We find that molecular geometries exist at which the singlet-triplet energy gap (exchange energy) is close to zero, so that rapid interconversion is possible. Calculations indicate that exchange energy is tuned by relative rotation of the donor and acceptor moieties about the bridge. Unlike other systems with low exchange energy, substantial oscillator strength is sustained at the singlet-triplet degeneracy point.

[Open circuit: the exchange of medical and scientific knowledge in Latin American in the early 20th century].

PubMed

Almeida, Marta de

2006-01-01

This article discusses the Latin American Medical Congresses and International Exhibitions on Hygiene held in the first few decades of the 20th century as a strategy for underpinning and influencing medical knowledge within the specialized community itself and for public authorities, which were fundamental for presenting to society at large as they were seen as the vehicles of official know-how on the art of medicating. These events made up part of a broader movement to internationalize and coordinate the professional field of medicine in Latin America. The article further suggests that the activities that took place during these events played a key role in the propagation of ideas and exchange of experience between Latin American nations, forming a network of scientific exchange in the continent.

Applying secret sharing for HIS backup exchange.

PubMed

Kuroda, Tomohiro; Kimura, Eizen; Matsumura, Yasushi; Yamashita, Yoshinori; Hiramatsu, Haruhiko; Kume, Naoto; Sato, Atsushi

2013-01-01

To secure business continuity is indispensable for hospitals to fulfill its social responsibility under disasters. Although to back up the data of the hospital information system (HIS) at multiple remote sites is a key strategy of business continuity plan (BCP), the requirements to treat privacy sensitive data jack up the cost for the backup. The secret sharing is a method to split an original secret message up so that each individual piece is meaningless, but putting sufficient number of pieces together to reveal the original message. The secret sharing method eases us to exchange HIS backups between multiple hospitals. This paper evaluated the feasibility of the commercial secret sharing solution for HIS backup through several simulations. The result shows that the commercial solution is feasible to realize reasonable HIS backup exchange platform when template of contract between participating hospitals is ready.

The Experiences of State-Run Insurance Marketplaces That Use HealthCare.gov.

PubMed

Giovannelli, Justin; Lucia, Kevin

2015-09-01

States have flexibility in implementing the Affordable Care Act's health insurance marketplaces and may choose to become more (or less) involved in marketplace operations over time. Interest in new implementation approaches has increased as states seek to ensure the long-term financial stability of their exchanges and exercise local control over marketplace oversight. This brief explores the experiences of four states--Idaho, Nevada, New Mexico, and Oregon--that established their own exchanges but have operated them with support from the federal HealthCare.gov eligibility and enrollment platform. Drawing on discussions with policymakers, insurers, and brokers, we examine how these supported state-run marketplaces perform their key functions. We find that this model may offer states the ability to maximize their influence over their insurance markets, while limiting the financial risk of running an exchange.

Low-power cryptographic coprocessor for autonomous wireless sensor networks

NASA Astrophysics Data System (ADS)

Olszyna, Jakub; Winiecki, Wiesław

2013-10-01

The concept of autonomous wireless sensor networks involves energy harvesting, as well as effective management of system resources. Public-key cryptography (PKC) offers the advantage of elegant key agreement schemes with which a secret key can be securely established over unsecure channels. In addition to solving the key management problem, the other major application of PKC is digital signatures, with which non-repudiation of messages exchanges can be achieved. The motivation for studying low-power and area efficient modular arithmetic algorithms comes from enabling public-key security for low-power devices that can perform under constrained environment like autonomous wireless sensor networks. This paper presents a cryptographic coprocessor tailored to the autonomous wireless sensor networks constraints. Such hardware circuit is aimed to support the implementation of different public-key cryptosystems based on modular arithmetic in GF(p) and GF(2m). Key components of the coprocessor are described as GEZEL models and can be easily transformed to VHDL and implemented in hardware.

Tree ring imprints of long-term changes in climate in western Himalaya, India.

PubMed

Yadav, R R

2009-11-01

Tree-ring analyses from semi-arid to arid regions in western Himalaya show immense potential for developing millennia long climate records. Millennium and longer ring-width chronologies of Himalayan pencil juniper (Juniperus polycarpos), Himalayan pencil cedar (Cedrus deodara) and Chilgoza pine (Pinus gerardiana) have been developed from different sites in western Himalaya. Studies conducted so far on various conifer species indicate strong precipitation signatures in ring-width measurement series. The paucity of weather records from stations close to tree-ring sampling sites poses diffi culty in calibrating tree-ring data against climate data especially precipitation for its strong spatial variability in mountain regions. However, for the existence of strong coherence in temperature, even in data from distant stations, more robust temperature reconstructions representing regional and hemispheric signatures have been developed. Tree-ring records from the region indicate multi-century warm and cool anomalies consistent with the Medieval Warm Period and Little Ice Age anomalies. Signifi cant relationships noted between mean premonsoon temperature over the western Himalaya and ENSO features endorse utility of climate records from western Himalayan region in understanding long-term climate variability and attribution of anthropogenic impact.

Anion- or Cation-Exchange Membranes for NaBH4/H2O2 Fuel Cells?

PubMed Central

Šljukić, Biljana; Morais, Ana L.; Santos, Diogo M. F.; Sequeira, César A. C.

2012-01-01

Direct borohydride fuel cells (DBFC), which operate on sodium borohydride (NaBH4) as the fuel, and hydrogen peroxide (H2O2) as the oxidant, are receiving increasing attention. This is due to their promising use as power sources for space and underwater applications, where air is not available and gas storage poses obvious problems. One key factor to improve the performance of DBFCs concerns the type of separator used. Both anion- and cation-exchange membranes may be considered as potential separators for DBFC. In the present paper, the effect of the membrane type on the performance of laboratory NaBH4/H2O2 fuel cells using Pt electrodes is studied at room temperature. Two commercial ion-exchange membranes from Membranes International Inc., an anion-exchange membrane (AMI-7001S) and a cation-exchange membrane (CMI-7000S), are tested as ionic separators for the DBFC. The membranes are compared directly by the observation and analysis of the corresponding DBFC’s performance. Cell polarization, power density, stability, and durability tests are used in the membranes’ evaluation. Energy densities and specific capacities are estimated. Most tests conducted, clearly indicate a superior performance of the cation-exchange membranes over the anion-exchange membrane. The two membranes are also compared with several other previously tested commercial membranes. For long term cell operation, these membranes seem to outperform the stability of the benchmark Nafion membranes but further studies are still required to improve their instantaneous power load. PMID:24958292

Anion- or Cation-Exchange Membranes for NaBH4/H2O2 Fuel Cells?

PubMed

Sljukić, Biljana; Morais, Ana L; Santos, Diogo M F; Sequeira, César A C

2012-07-19

Direct borohydride fuel cells (DBFC), which operate on sodium borohydride (NaBH4) as the fuel, and hydrogen peroxide (H2O2) as the oxidant, are receiving increasing attention. This is due to their promising use as power sources for space and underwater applications, where air is not available and gas storage poses obvious problems. One key factor to improve the performance of DBFCs concerns the type of separator used. Both anion- and cation-exchange membranes may be considered as potential separators for DBFC. In the present paper, the effect of the membrane type on the performance of laboratory NaBH4/H2O2 fuel cells using Pt electrodes is studied at room temperature. Two commercial ion-exchange membranes from Membranes International Inc., an anion-exchange membrane (AMI-7001S) and a cation-exchange membrane (CMI-7000S), are tested as ionic separators for the DBFC. The membranes are compared directly by the observation and analysis of the corresponding DBFC's performance. Cell polarization, power density, stability, and durability tests are used in the membranes' evaluation. Energy densities and specific capacities are estimated. Most tests conducted, clearly indicate a superior performance of the cation-exchange membranes over the anion-exchange membrane. The two membranes are also compared with several other previously tested commercial membranes. For long term cell operation, these membranes seem to outperform the stability of the benchmark Nafion membranes but further studies are still required to improve their instantaneous power load.

Peripheral Visions: Californian-Australian Environmental Contacts, c. 1850s-1910.

ERIC Educational Resources Information Center

Tyrrell, Ian

1997-01-01

Offers a comparative and transnational study of environmental contacts between California and Australia. Analyzes concepts of the ideal society, the influence of isolation, distant markets, and climate similarities, using world system and cultural landscape theories. Discusses key exchanges of plants and policies regarding irrigation and…

Droplet Evaporator For High-Capacity Heat Transfer

NASA Technical Reports Server (NTRS)

Valenzuela, Javier A.

1993-01-01

Proposed heat-exchange scheme boosts heat transfer per unit area. Key component is generator that fires uniform size droplets of subcooled liquid at hot plate. On impact, droplets spread out and evaporate almost instantly, removing heat from plate. In practice, many generator nozzles arrayed over evaporator plate.

Development and evaluation of an ammonia bidirectional flux parameterization for air quality models

EPA Science Inventory

Ammonia is an important contributor to particulate matter in the atmosphere and can significantly impact terrestrial and aquatic ecosystems. Surface exchange between the atmosphere and biosphere is a key part of the ammonia cycle. New modeling techniques are being developed for u...

Demonstration of the Potential of Magnetic Tunnel Junctions for a Universal RAM Technology

NASA Astrophysics Data System (ADS)

Gallagher, William J.

2000-03-01

Over the past four years, tunnel junctions with magnetic electrodes have emerged as promising devices for future magnetoresistive sensing and for information storage. This talk will review advances in these devices, focusing particularly on the use of magnetic tunnel junctions for magnetic random access memory (MRAM). Exchange-biased versions of magnetic tunnel junctions (MTJs) in particular will be shown to have useful properties for forming magnetic memory storage elements in a novel cross-point architecture. Exchange-biased MTJ elements have been made with areas as small as 0.1 square microns and have shown magnetoresistance values exceeding 40 The potential of exchange-biased MTJs for MRAM has been most seriously explored in a demonstration experiment involving the integration of 0.25 micron CMOS technology with a special magnetic tunnel junction "back end." The magnetic back end is based upon multi-layer magnetic tunnel junction growth technology which was developed using research-scale equipment and one-inch size substrates. For the demonstration, the CMOS wafers processed through two metal layers were cut into one-inch squares for depositions of bottom-pinned exchange-biased magnetic tunnel junctions. The samples were then processed through four additional lithographic levels to complete the circuits. The demonstration focused attention on a number of processing and device issues that were addressed successfully enough that key performance aspects of MTJ MRAM were demonstrated in 1 K bit arrays, including reads and writes in less than 10 ns and nonvolatility. While other key issues remain to be addressed, these results suggest that MTJ MRAM might simultaneously provide much of the functionality now provided separately by SRAM, DRAM, and NVRAM.

Password-only authenticated three-party key exchange proven secure against insider dictionary attacks.

PubMed

Nam, Junghyun; Choo, Kim-Kwang Raymond; Paik, Juryon; Won, Dongho

2014-01-01

While a number of protocols for password-only authenticated key exchange (PAKE) in the 3-party setting have been proposed, it still remains a challenging task to prove the security of a 3-party PAKE protocol against insider dictionary attacks. To the best of our knowledge, there is no 3-party PAKE protocol that carries a formal proof, or even definition, of security against insider dictionary attacks. In this paper, we present the first 3-party PAKE protocol proven secure against both online and offline dictionary attacks as well as insider and outsider dictionary attacks. Our construct can be viewed as a protocol compiler that transforms any 2-party PAKE protocol into a 3-party PAKE protocol with 2 additional rounds of communication. We also present a simple and intuitive approach of formally modelling dictionary attacks in the password-only 3-party setting, which significantly reduces the complexity of proving the security of 3-party PAKE protocols against dictionary attacks. In addition, we investigate the security of the well-known 3-party PAKE protocol, called GPAKE, due to Abdalla et al. (2005, 2006), and demonstrate that the security of GPAKE against online dictionary attacks depends heavily on the composition of its two building blocks, namely a 2-party PAKE protocol and a 3-party key distribution protocol.

Drought-induced defoliation and long periods of near-zero gas exchange play a key role in accentuating metabolic decline of Scots pine.

PubMed

Poyatos, Rafael; Aguadé, David; Galiano, Lucía; Mencuccini, Maurizio; Martínez-Vilalta, Jordi

2013-10-01

Drought-induced defoliation has recently been associated with the depletion of carbon reserves and increased mortality risk in Scots pine (Pinus sylvestris). We hypothesize that defoliated individuals are more sensitive to drought, implying that potentially higher gas exchange (per unit of leaf area) during wet periods may not compensate for their reduced photosynthetic area. We measured sap flow, needle water potentials and whole-tree hydraulic conductance to analyse the drought responses of co-occurring defoliated and nondefoliated Scots pines in northeast Spain during typical (2010) and extreme (2011) drought conditions. Defoliated Scots pines showed higher sap flow per unit leaf area during spring, but were more sensitive to summer drought, relative to nondefoliated pines. This pattern was associated with a steeper decline in soil-to-leaf hydraulic conductance with drought and an enhanced sensitivity of canopy conductance to soil water availability. Near-homeostasis in midday water potentials was observed across years and defoliation classes, with minimum values of -2.5 MPa. Enhanced sensitivity to drought and prolonged periods of near-zero gas exchange were consistent with low levels of carbohydrate reserves in defoliated trees. Our results support the critical links between defoliation, water and carbon availability, and their key roles in determining tree survival and recovery under drought. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Multi-party quantum key agreement with five-qubit brown states

NASA Astrophysics Data System (ADS)

Cai, Tao; Jiang, Min; Cao, Gang

2018-05-01

In this paper, we propose a multi-party quantum key agreement protocol with five-qubit brown states and single-qubit measurements. Our multi-party protocol ensures each participant to contribute equally to the agreement key. Each party performs three single-qubit unitary operations on three qubits of each brown state. Finally, by measuring brown states and decoding the measurement results, all participants can negotiate a shared secret key without classical bits exchange between them. With the analysis of security, our protocol demonstrates that it can resist against both outsider and participant attacks. Compared with other schemes, it also possesses a higher information efficiency. In terms of physical operation, it requires single-qubit measurements only which weakens the hardware requirements of participant and has a better operating flexibility.

Key characteristics of knowledge transfer and exchange in healthcare: integrative literature review.

PubMed

Pentland, Duncan; Forsyth, Kirsty; Maciver, Donald; Walsh, Mike; Murray, Richard; Irvine, Linda; Sikora, Simon

2011-07-01

This paper presents the results of a review of literature relating to knowledge transfer and exchange in healthcare. Treatment, planning and policy decisions in contemporary nursing and healthcare should be based on sound evidence wherever possible, but research knowledge remains generally underused. Knowledge transfer and exchange initiatives aim to facilitate the accessibility, application and production of evidence and may provide solutions to this challenge. This review was conducted to help inform the design and implementation of knowledge transfer and exchange activities for a large healthcare organization. Databases: ASSIA, Business Source Premier, CINAHL, PsychInfo, Medline and the Cochrane Database of Systematic Reviews. An integrative literature review was carried out including an extensive literature search. English language systematic reviews, literature reviews, primary quantitative and qualitative papers and grey literature of high relevance evaluating, describing or discussing knowledge transfer or exchange activities in healthcare were included for review (January 1990-September 2009). Thirty-three papers were reviewed (four systematic reviews, nine literature reviews, one environmental scan, nine empirical studies and ten case studies). Robust research into knowledge transfer and exchange in healthcare is limited. Analysis of a wide range of evidence indicates a number of commonly featured characteristics but further evaluation of these activities would benefit their application in facilitating evidence-based practice in nursing. © 2011 The Authors. Journal of Advanced Nursing © 2011 Blackwell Publishing Ltd.

Symmetric Blind Information Reconciliation for Quantum Key Distribution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kiktenko, Evgeniy O.; Trushechkin, Anton S.; Lim, Charles Ci Wen

Quantum key distribution (QKD) is a quantum-proof key-exchange scheme which is fast approaching the communication industry. An essential component in QKD is the information reconciliation step, which is used for correcting the quantum-channel noise errors. The recently suggested blind-reconciliation technique, based on low-density parity-check codes, offers remarkable prospectives for efficient information reconciliation without an a priori quantum bit error rate estimation. We suggest an improvement of the blind-information-reconciliation protocol promoting a significant increase in the efficiency of the procedure and reducing its interactivity. Finally, the proposed technique is based on introducing symmetry in operations of parties, and the consideration ofmore » results of unsuccessful belief-propagation decodings.« less

Symmetric Blind Information Reconciliation for Quantum Key Distribution

DOE PAGES

Kiktenko, Evgeniy O.; Trushechkin, Anton S.; Lim, Charles Ci Wen; ...

2017-10-27

Quantum key distribution (QKD) is a quantum-proof key-exchange scheme which is fast approaching the communication industry. An essential component in QKD is the information reconciliation step, which is used for correcting the quantum-channel noise errors. The recently suggested blind-reconciliation technique, based on low-density parity-check codes, offers remarkable prospectives for efficient information reconciliation without an a priori quantum bit error rate estimation. We suggest an improvement of the blind-information-reconciliation protocol promoting a significant increase in the efficiency of the procedure and reducing its interactivity. Finally, the proposed technique is based on introducing symmetry in operations of parties, and the consideration ofmore » results of unsuccessful belief-propagation decodings.« less

Symmetric Blind Information Reconciliation for Quantum Key Distribution

NASA Astrophysics Data System (ADS)

Kiktenko, E. O.; Trushechkin, A. S.; Lim, C. C. W.; Kurochkin, Y. V.; Fedorov, A. K.

2017-10-01

Quantum key distribution (QKD) is a quantum-proof key-exchange scheme which is fast approaching the communication industry. An essential component in QKD is the information reconciliation step, which is used for correcting the quantum-channel noise errors. The recently suggested blind-reconciliation technique, based on low-density parity-check codes, offers remarkable prospectives for efficient information reconciliation without an a priori quantum bit error rate estimation. We suggest an improvement of the blind-information-reconciliation protocol promoting a significant increase in the efficiency of the procedure and reducing its interactivity. The proposed technique is based on introducing symmetry in operations of parties, and the consideration of results of unsuccessful belief-propagation decodings.

Western Policy Exchanges

ERIC Educational Resources Information Center

Western Interstate Commission for Higher Education, 2009

2009-01-01

In December 2008, with funding from the Bill and Melinda Gates Foundation and in partnership with the Data Quality Campaign, the Western Interstate Commission for Higher Education (WICHE) hosted a meeting of the West's key leaders in building state-wide integrated longitudinal data systems. Such data systems are essential to developing a better…

Linguistic Human Rights Discourse in Deaf Community Activism

ERIC Educational Resources Information Center

Murray, Joseph J.

2015-01-01

The past three decades of activism for linguistic human rights (Skutnabb-Kangas 2000) have witnessed examples of language planning by various national and supranational actors in national and international spaces, with an exchange of ideas and strategies employed by national, regional, and worldwide organizations. In many countries a key goal of…

Examining Intercultural Competency through Social Exchange Theory

ERIC Educational Resources Information Center

Pillay, Soma; James, Reynold

2015-01-01

Intercultural competency (ICC) has been an extensively researched area within the past decade, given the broad consensus that this trait constitutes one of the key competencies of the 21st century manager. However, somewhat under-explored are aspects including the implications and effects that pedagogies such as blended learning have on the…

Air pollution from ground transportation : an assessment of causes, strategies and tactics, and proposed actions for the international community

DOT National Transportation Integrated Search

2002-01-01

Accessibility is a key ingredient of well-being and prosperity in contemporary societies. : The ability of individuals, families, entrepreneurs and firms to exchange goods and services, to be : where activities are being carried out, and to interact ...

Marketing Power Tools for Building Better Connections.

ERIC Educational Resources Information Center

Goldman, Karen Denard

This paper proposes use of marketing methods to improve college health services and enhance their perceived value. Ten key marketing principles are defined: (1) value of the service as seen by the target population; (2) exchange clients perceive benefits received as exceeding perceived costs; (3) competition offering a better product than the…

Data-driven diagnostics of terrestrial carbon dynamics over North America

USDA-ARS?s Scientific Manuscript database

The exchange of carbon dioxide is a key measure of ecosystem metabolism and a critical intersection between the terrestrial biosphere and the Earth's climate. Despite the general agreement that the terrestrial ecosystems in North America provide a sizeable carbon sink, the size and distribution of t...

Two-Way Immersion: A Key to Global Awareness.

ERIC Educational Resources Information Center

Howard, Elizabeth R.

2002-01-01

Describes the use of two-way immersion education to provide students with opportunities to understand and appreciate other countries and cultures. The main features of two-way immersion education are bilingual language instruction, cross-cultural understanding, and international exchanges. Includes case study of two-way immersion at the Alicia…

Hypnosis and Human Development: Interpersonal Influence of Intrapersonal Processes.

ERIC Educational Resources Information Center

Vandenberg, Brian

1998-01-01

Examines the relationship between hypnosis and human development. Defines hypnosis within a communications framework, and identifies essential features of hypnosis in the communicative exchanges of the first months of life; this forces a reconsideration of the understanding of the ontogenesis of hypnosis. Identifies four key features of hypnosis,…

Development and Evaluation of an Ammonia Bi-Directional Flux Model for Air Quality Models

EPA Science Inventory

Ammonia is an important contributor to particulate matter in the atmosphere and can significantly impact terrestrial and aquatic ecosystems. Surface exchange between the atmosphere and biosphere is a key part of the ammonia cycle. Agriculture, in particular. is a large source of...

An Investigation of Factors Associated with Student Participation in Study Abroad

ERIC Educational Resources Information Center

Doyle, Stephanie; Gendall, Philip; Meyer, Luanna H.; Hoek, Janet; Tait, Carolyn; McKenzie, Lynanne; Loorparg, Avatar

2010-01-01

International student exchange programs are widely promoted in higher education as a means of developing desirable intercultural skills and understanding among students. This multimethod study employed data from student surveys, tertiary institution case studies, and interviews with key stakeholders to identify factors that inhibited or promoted…

Communication protocol in chassis detecting wireless transmission system based on WiFi

USDA-ARS?s Scientific Manuscript database

In chassis detecting wireless transmission system, the wireless network communication protocol plays a key role in the information exchange and synchronization between the host and chassis PDA. This paper presents a wireless network transmission protocol based on TCP/IP which makes the rules of info...

Adjusting Conceptual Pacts in Three-Party Conversation

ERIC Educational Resources Information Center

Yoon, Si On; Brown-Schmidt, Sarah

2014-01-01

During conversation, partners develop representations of jointly known information--the common ground--and use this knowledge to guide subsequent linguistic exchanges. Extensive research on 2-party conversation has offered key insights into this process, in particular, its partner-specificity: Common ground that is shared with 1 partner is not…

Imagining a Profession: A Beginning Teacher's Story of Isolation

ERIC Educational Resources Information Center

McCluskey, Kerryn; Sim, Cheryl; Johnson, Greer

2011-01-01

Policy documents informing the profession of teaching in Australia and elsewhere explicitly recommend nurturing those new to the profession working collaboratively with colleagues. Key to the development and growth of beginning teachers is the informal exchange of ideas and knowledge between colleagues--essentially through the functioning of a…

Ecosystem-scale VOC fluxes during an extreme drought in a broad-leaf temperate forest of the Missouri Ozarks (central USA)

EPA Science Inventory

Considerable amounts and varieties of biogenic volatile organic compounds (BVOCs) are exchanged between vegetation and the surrounding air. These BVOCs play key ecological and atmospheric roles that must be adequately represented for accurately modeling the coupled biosphere-atmo...

Joint Leaf chlorophyll and leaf area index retrieval from Landsat data using a regularized model inversion system

USDA-ARS?s Scientific Manuscript database

Leaf area index (LAI) and leaf chlorophyll (Chl) content represent key biophysical and biochemical controls on water, energy and carbon exchange processes in the terrestrial biosphere. In combination, LAI and leaf Chl content provide critical information on vegetation density, vitality and photosynt...

[Request for an abortion, the role of frontline professionals].

PubMed

Picoche, Claire

2015-12-01

The reception given by professionals to a woman requesting an elective abortion is key. The initial exchange of information is usually by telephone. Time is limited, hence the requirement for caregivers to demonstrate their availability and professionalism in organising personalised care. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

A Transparent Translation from Legacy System Model into Common Information Model: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Fei; Simpson, Jeffrey; Zhang, Yingchen

Advance in smart grid is forcing utilities towards better monitoring, control and analysis of distribution systems, and requires extensive cyber-based intelligent systems and applications to realize various functionalities. The ability of systems, or components within systems, to interact and exchange services or information with each other is the key to the success of smart grid technologies, and it requires efficient information exchanging and data sharing infrastructure. The Common Information Model (CIM) is a standard that allows different applications to exchange information about an electrical system, and it has become a widely accepted solution for information exchange among different platforms andmore » applications. However, most existing legacy systems are not developed using CIM, but using their own languages. Integrating such legacy systems is a challenge for utilities, and the appropriate utilization of the integrated legacy systems is even more intricate. Thus, this paper has developed an approach and open-source tool in order to translate legacy system models into CIM format. The developed tool is tested for a commercial distribution management system and simulation results have proved its effectiveness.« less

Rethinking the Combination of Proton Exchanger Inhibitors in Cancer Therapy.

PubMed

Iessi, Elisabetta; Logozzi, Mariantonia; Mizzoni, Davide; Di Raimo, Rossella; Supuran, Claudiu T; Fais, Stefano

2017-12-23

Microenvironmental acidity is becoming a key target for the new age of cancer treatment. In fact, while cancer is characterized by genetic heterogeneity, extracellular acidity is a common phenotype of almost all cancers. To survive and proliferate under acidic conditions, tumor cells up-regulate proton exchangers and transporters (mainly V-ATPase, Na⁺/H⁺ exchanger (NHE), monocarboxylate transporters (MCTs), and carbonic anhydrases (CAs)), that actively extrude excess protons, avoiding intracellular accumulation of toxic molecules, thus becoming a sort of survival option with many similarities compared with unicellular microorganisms. These systems are also involved in the unresponsiveness or resistance to chemotherapy, leading to the protection of cancer cells from the vast majority of drugs, that when protonated in the acidic tumor microenvironment, do not enter into cancer cells. Indeed, as usually occurs in the progression versus malignancy, resistant tumor clones emerge and proliferate, following a transient initial response to a therapy, thus giving rise to more malignant behavior and rapid tumor progression. Recent studies are supporting the use of a cocktail of proton exchanger inhibitors as a new strategy against cancer.

Rethinking the Combination of Proton Exchanger Inhibitors in Cancer Therapy

PubMed Central

Iessi, Elisabetta; Logozzi, Mariantonia; Mizzoni, Davide; Di Raimo, Rossella; Fais, Stefano

2017-01-01

Microenvironmental acidity is becoming a key target for the new age of cancer treatment. In fact, while cancer is characterized by genetic heterogeneity, extracellular acidity is a common phenotype of almost all cancers. To survive and proliferate under acidic conditions, tumor cells up-regulate proton exchangers and transporters (mainly V-ATPase, Na+/H+ exchanger (NHE), monocarboxylate transporters (MCTs), and carbonic anhydrases (CAs)), that actively extrude excess protons, avoiding intracellular accumulation of toxic molecules, thus becoming a sort of survival option with many similarities compared with unicellular microorganisms. These systems are also involved in the unresponsiveness or resistance to chemotherapy, leading to the protection of cancer cells from the vast majority of drugs, that when protonated in the acidic tumor microenvironment, do not enter into cancer cells. Indeed, as usually occurs in the progression versus malignancy, resistant tumor clones emerge and proliferate, following a transient initial response to a therapy, thus giving rise to more malignant behavior and rapid tumor progression. Recent studies are supporting the use of a cocktail of proton exchanger inhibitors as a new strategy against cancer. PMID:29295495

Symmetry and the geometric phase in ultracold hydrogen-exchange reactions

NASA Astrophysics Data System (ADS)

Croft, J. F. E.; Hazra, J.; Balakrishnan, N.; Kendrick, B. K.

2017-08-01

Quantum reactive scattering calculations are reported for the ultracold hydrogen-exchange reaction and its non-reactive atom-exchange isotopic counterparts, proceeding from excited rotational states. It is shown that while the geometric phase (GP) does not necessarily control the reaction to all final states, one can always find final states where it does. For the isotopic counterpart reactions, these states can be used to make a measurement of the GP effect by separately measuring the even and odd symmetry contributions, which experimentally requires nuclear-spin final-state resolution. This follows from symmetry considerations that make the even and odd identical-particle exchange symmetry wavefunctions which include the GP locally equivalent to the opposite symmetry wavefunctions which do not. It is shown how this equivalence can be used to define a constant which quantifies the GP effect and can be obtained solely from experimentally observable rates. This equivalence reflects the important role that discrete symmetries play in ultracold chemistry and highlights the key role that ultracold reactions can play in understanding fundamental aspects of chemical reactivity more generally.

Verifier-based three-party authentication schemes using extended chaotic maps for data exchange in telecare medicine information systems.

PubMed

Lee, Tian-Fu

2014-12-01

Telecare medicine information systems provide a communicating platform for accessing remote medical resources through public networks, and help health care workers and medical personnel to rapidly making correct clinical decisions and treatments. An authentication scheme for data exchange in telecare medicine information systems enables legal users in hospitals and medical institutes to establish a secure channel and exchange electronic medical records or electronic health records securely and efficiently. This investigation develops an efficient and secure verified-based three-party authentication scheme by using extended chaotic maps for data exchange in telecare medicine information systems. The proposed scheme does not require server's public keys and avoids time-consuming modular exponential computations and scalar multiplications on elliptic curve used in previous related approaches. Additionally, the proposed scheme is proven secure in the random oracle model, and realizes the lower bounds of messages and rounds in communications. Compared to related verified-based approaches, the proposed scheme not only possesses higher security, but also has lower computational cost and fewer transmissions. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Towards a theory of tropical/midlatitude mass exchange from the earth's surface through the stratosphere

NASA Technical Reports Server (NTRS)

Hartley, Dana

1995-01-01

The main focus of this work is to understand the dynamics of mass exchange between the tropics and the midlatitudes and to determine any links between tropospheric exchange and that in the stratosphere. We have approached this problem from two different perspectives. The first is aimed towards understanding the troposphere's role in inducing lower stratospheric tropical/midlatitude exchange. For this project we focus on observational analysis of the lower stratosphere to assess the key regions of transport in/out of the tropics and to what extent this transport is driven by tropospheric processes. The second approach is to determine the extent to which stratospheric processes influence the troposphere. In this project we are performing potential vorticity (PV) inversions to assess the winds induced near the tropopause when the stratospheric polar vortex is displaced equatorward. These are each discussed in more detail in the subsections below. Also, we have organized a session on Tropical/Midlatitude Interaction and Transport at the Fall AGU where we will be showing our latest results.

General Formalism of Mass Scaling Approach for Replica-Exchange Molecular Dynamics and its Application

NASA Astrophysics Data System (ADS)

Nagai, Tetsuro

2017-01-01

Replica-exchange molecular dynamics (REMD) has demonstrated its efficiency by combining trajectories of a wide range of temperatures. As an extension of the method, the author formalizes the mass-manipulating replica-exchange molecular dynamics (MMREMD) method that allows for arbitrary mass scaling with respect to temperature and individual particles. The formalism enables the versatile application of mass-scaling approaches to the REMD method. The key change introduced in the novel formalism is the generalized rules for the velocity and momentum scaling after accepted replica-exchange attempts. As an application of this general formalism, the refinement of the viscosity-REMD (V-REMD) method [P. H. Nguyen, J. Chem. Phys. 132, 144109 (2010)] is presented. Numerical results are provided using a pilot system, demonstrating easier and more optimized applicability of the new version of V-REMD as well as the importance of adherence to the generalized velocity scaling rules. With the new formalism, more sound and efficient simulations will be performed.

Exchange pathways of plastoquinone and plastoquinol in the photosystem II complex

PubMed Central

Van Eerden, Floris J.; Melo, Manuel N.; Frederix, Pim W. J. M.; Periole, Xavier; Marrink, Siewert J.

2017-01-01

Plastoquinone (PLQ) acts as an electron carrier between photosystem II (PSII) and the cytochrome b6f complex. To understand how PLQ enters and leaves PSII, here we show results of coarse grained molecular dynamics simulations of PSII embedded in the thylakoid membrane, covering a total simulation time of more than 0.5 ms. The long time scale allows the observation of many spontaneous entries of PLQ into PSII, and the unbinding of plastoquinol (PLQol) from the complex. In addition to the two known channels, we observe a third channel for PLQ/PLQol diffusion between the thylakoid membrane and the PLQ binding sites. Our simulations point to a promiscuous diffusion mechanism in which all three channels function as entry and exit channels. The exchange cavity serves as a PLQ reservoir. Our simulations provide a direct view on the exchange of electron carriers, a key step of the photosynthesis machinery. PMID:28489071

Molecular digital pathology: progress and potential of exchanging molecular data.

PubMed

Roy, Somak; Pfeifer, John D; LaFramboise, William A; Pantanowitz, Liron

2016-09-01

Many of the demands to perform next generation sequencing (NGS) in the clinical laboratory can be resolved using the principles of telepathology. Molecular telepathology can allow facilities to outsource all or a portion of their NGS operation such as cloud computing, bioinformatics pipelines, variant data management, and knowledge curation. Clinical pathology laboratories can electronically share diverse types of molecular data with reference laboratories, technology service providers, and/or regulatory agencies. Exchange of electronic molecular data allows laboratories to perform validation of rare diseases using foreign data, check the accuracy of their test results against benchmarks, and leverage in silico proficiency testing. This review covers the emerging subject of molecular telepathology, describes clinical use cases for the appropriate exchange of molecular data, and highlights key issues such as data integrity, interoperable formats for massive genomic datasets, security, malpractice and emerging regulations involved with this novel practice.

Spatially resolved multicolor CsPbX 3 nanowire heterojunctions via anion exchange

DOE PAGES

Dou, Letian; Lai, Minliang; Kley, Christopher S.; ...

2017-06-26

Halide perovskites are promising semiconductor materials for solution-processed optoelectronic devices. Their strong ionic bonding nature results in highly dynamic crystal lattices, inherently allowing rapid ion exchange at the solid–vapor and solid–liquid interface. In this paper, we show that the anion-exchange chemistry can be precisely controlled in single-crystalline halide perovskite nanomaterials when combined with nanofabrication techniques. We demonstrate spatially resolved multicolor CsPbX 3 (X = Cl, Br, I, or alloy of two halides) nanowire heterojunctions with a pixel size down to 500 nm with the photoluminescence tunable over the entire visible spectrum. In addition, the heterojunctions show distinct electronic states acrossmore » the interface, as revealed by Kelvin probe force microscopy. Finally, these perovskite heterojunctions represent key building blocks for high-resolution multicolor displays beyond current state-of-the-art technology as well as high-density diode/transistor arrays.« less

Youngsters do not pay attention to conversational rules: is this so for nonhuman primates?

PubMed

Lemasson, A; Glas, L; Barbu, S; Lacroix, A; Guilloux, M; Remeuf, K; Koda, H

2011-01-01

The potentiality to find precursors of human language in nonhuman primates is questioned because of differences related to the genetic determinism of human and nonhuman primate acoustic structures. Limiting the debate to production and acoustic plasticity might have led to underestimating parallels between human and nonhuman primates. Adult-young differences concerning vocal usage have been reported in various primate species. A key feature of language is the ability to converse, respecting turn-taking rules. Turn-taking structures some nonhuman primates' adult vocal exchanges, but the development and the cognitive relevancy of this rule have never been investigated in monkeys. Our observations of Campbell's monkeys' spontaneous vocal utterances revealed that juveniles broke the turn-taking rule more often than did experienced adults. Only adults displayed different levels of interest when hearing playbacks of vocal exchanges respecting or not the turn-taking rule. This study strengthens parallels between human conversations and nonhuman primate vocal exchanges.

Mapping transiently formed and sparsely populated conformations on a complex energy landscape.

PubMed

Wang, Yong; Papaleo, Elena; Lindorff-Larsen, Kresten

2016-08-23

Determining the structures, kinetics, thermodynamics and mechanisms that underlie conformational exchange processes in proteins remains extremely difficult. Only in favourable cases is it possible to provide atomic-level descriptions of sparsely populated and transiently formed alternative conformations. Here we benchmark the ability of enhanced-sampling molecular dynamics simulations to determine the free energy landscape of the L99A cavity mutant of T4 lysozyme. We find that the simulations capture key properties previously measured by NMR relaxation dispersion methods including the structure of a minor conformation, the kinetics and thermodynamics of conformational exchange, and the effect of mutations. We discover a new tunnel that involves the transient exposure towards the solvent of an internal cavity, and show it to be relevant for ligand escape. Together, our results provide a comprehensive view of the structural landscape of a protein, and point forward to studies of conformational exchange in systems that are less characterized experimentally.

[Healthcare marketing elements].

PubMed

Ameri, Cinzia; Fiorini, Fulvio

2014-01-01

Marketing puts its foundation on a few key concepts: need-demand, product-service, satisfaction, exchange, market, or business structure manufacturing / supply. The combination of these elements allows you to build an effective marketing strategy. Crucial in this respect is to remember the Porter matrix, which shows that for a correct analysis of the relevant market is necessary to refer to the "five forces at play", ie: customers, competitors, new entrants and substitutes threat. Another key lever for proper marketing oriented approach is the continuous and constant monitoring of the application, anticipating their dissatisfactions.

Synthesis of strong SiV photoluminescent diamond particles on silica optical fiber by chemical vapor deposition

NASA Astrophysics Data System (ADS)

Yang, Zongchun; Mei, Yingshuang; Chen, Chengke; Ruan, Yinlan; Hu, Xiaojun

2018-03-01

Not Available Project supported by the National Natural Science Foundation of China (Grant Nos. 50972129 and 50602039), the International Science Technology Cooperation Program of China (Grant No. 2014DFR51160), the National Key Research and Development Program of China (Grant No. 2016YFE0133200), European Unionʼs Horizon 2020 Research and Innovation Staff Exchange (RISE) Scheme (Grant No. 734578), and the One Belt and One Road International Cooperation Project from Key Research and Development Program of Zhejiang Province, China (Grant No. 2018C04021).

Advances in membrane technology for the NASA redox energy storage system

NASA Technical Reports Server (NTRS)

Ling, J. S.; Charleston, J.

1980-01-01

Anion exchange membranes used in the system serve as a charge transferring medium as well as a reactant separator and are the key enabling component in this storage technology. Each membrane formulation undergoes a series of screening tests for area-resistivity, static (non-flow) diffusion rate determination, and performance in Redox systems. The CDIL series of membranes has, by virtue of its chemical stability and high ion exchange capacity, demonstrated superior properties in the redox environment. Additional resistivity results at several acid and iron solution concentrations, iron diffusion rates, and time dependent iron fouling of the various membrane formulations are presented in comparison to past standard formulations.

Perspectives of an Interdisciplinaryg Research Team to Engage Practice: Lessons from a Knowledge Exchange Trainee Experience

PubMed Central

Urquhart, Robin L.; Johnston, Grace M.; McVorran, Shauna M.; Burge, Fred I.

2010-01-01

End-of-life (EOL) care is an area of health services that will ultimately affect us all. To share the knowledge emerging from EOL research and to address inequities in the quality of EOL care in Nova Scotia, a knowledge exchange (KE) trainee was hired to translate research and surveillance into a Surveillance Report. The purpose of this paper is to reflect upon this initiative and share the research team's perspectives on their KE experiences. We describe four key competencies of the KE trainee selected, and discuss lessons learned from this KE trainee experience, to expand our understanding of KE. PMID:21532769

Distributional Preferences, Reciprocity-Like Behavior, and Efficiency in Bilateral Exchange

PubMed Central

Benjamin, Daniel J.

2014-01-01

Under what conditions do distributional preferences, such as altruism or a concern for fair outcomes, generate efficient trade? I analyze theoretically a simple bilateral exchange game: each player sequentially takes an action that reduces his own material payoff but increases the other player’s. Each player’s preferences may depend on both his/her own material payoff and the other player’s. I identify two key properties of the second-mover’s preferences: indifference curves kinked around “fair” material-payoff distributions, and materials payoffs entering preferences as “normal goods.” Either property can drive reciprocity-like behavior and generate a Pareto efficient outcome. PMID:25664144

Primary Health Care: Comparing Public Health Nursing Models in Ireland and Norway

PubMed Central

Leahy-Warren, Patricia; Day, Mary Rose

2013-01-01

Health of populations is determined by a multitude of contextual factors. Primary Health Care Reform endeavors to meet the broad health needs of populations and remains on international health agendas. Public health nurses are key professionals in the delivery of primary health care, and it is important for them to learn from global experiences. International collaboration is often facilitated by academic exchanges. As a result of one such exchange, an international PHN collaboration took place. The aim of this paper is to analyse the similarities and differences in public health nursing in Ireland and Norway within the context of primary care. PMID:23606956

Significance of independent radon entry rate and air exchange rate assessment for the purpose of radon mitigation effectiveness proper evaluation: case studies.

PubMed

Froňka, A; Jílek, K; Moučka, L; Brabec, M

2011-05-01

Two new single-family houses identified as insufficient with regard to existing radon barrier efficiency, have been selected for further examination. A complex set of radon diagnosis procedures has been applied in order to localise and quantify radon entry pathways into the indoor environment. Independent assessment of radon entry rate and air exchange rate has been carried out using the continuous indoor radon measurement and a specific tracer gas application. Simultaneous assessment of these key determining factors has turned out to be absolutely crucial in the context of major cause identification of elevated indoor radon concentration.

Dependence on collision energy of the stereodynamical properties of the 18O + 32O2 exchange reaction

NASA Astrophysics Data System (ADS)

Privat, E.; Guillon, G.; Honvault, P.

2018-06-01

We report a quantum stereodynamical study of the 18O + 16O16O(v = 0, j = 1) → 18O16O(v‧ = 0, j‧) + 16O oxygen exchange reaction at four different collision energies. We calculated the polarisation moments and generated stereodynamical portraits related to the key vectors involved in this collision process. Ozone complex-forming approaches of reactants are then deduced. The results indicate that different approaches are possible but strongly depend on the collision energy and other parameters of the collision. We also conclude that the reaction globally tends to favour a perpendicular approach with increasing energy.

Kinetics of surfactant-mediated epitaxy of III-V semiconductors

NASA Astrophysics Data System (ADS)

Grandjean, N.; Massies, J.

1996-05-01

Surfactant-mediated epitaxy (SME) of III-V semiconductors is studied in the case of the GaAs(001) growth using Te as surfactant. To account for the strong surface segregation of Te, a phenomenological exchange mechanism is used. This process explains the reduction of the surface diffusion length evidenced by scanning tunneling microscopy (STM). However, this kinetics effect is observed only for restricted growth conditions: the As surface coverage should be sufficient to allow the exchange process. STM results as well as Monte Carlo simulations clearly show that the group-V element surface coverage plays a key role in the kinetics of SME of III-V semiconductors.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nawaz, Kashif

Separate sensible and latent cooling systems offer significant increases in the overall performance of cooling/dehumidification systems compared with conventional vapor-compression air-conditioning systems. Key to the energy efficiency of such systems is the performance of the heat and mass exchangers that provide sensible cooling and dehumidification. A novel design is proposed for dehumidification applications, deploying metal foam as a substrate coated with solid desiccants. The current report provides some preliminary information regarding the development of the technology and discusses factors such as manufacturing of desiccants, characterization of desiccants, and development of the metal foam heat exchanger. All three aspects provide themore » necessary infrastructure for further development and validation of the proposed concept.« less

Influence of temperature on measurements of the CO2 compensation point: differences between the Laisk and O2-exchange methods.

PubMed

Walker, Berkley J; Cousins, Asaph B

2013-04-01

The CO2 compensation point in the absence of day respiration (Γ*) is a key parameter for modelling leaf CO2 exchange. Γ* links the kinetics of ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco) with the stoichiometry of CO2 released per Rubisco oxygenation from photorespiration (α), two essential components of biochemical models of photosynthesis. There are two main gas-exchange methods for measuring Γ*: (i) the Laisk method, which requires estimates of mesophyll conductance to CO2 (g m) and (ii) measurements of O2 isotope exchange, which assume constant values of α and a fixed stoichiometry between O2 uptake and Rubisco oxygenation. In this study, the temperature response of Γ* measured using the Laisk and O2-exchange methods was compared under ambient (25 °C) and elevated (35 °C) temperatures to determine whether both methods yielded similar results. Previously published temperature responses of Γ* estimated with the Laisk and O2-exchange methods in Nicotiana tabacum demonstrated that the Laisk-derived model of Γ* was more sensitive to temperature compared with the O2-exchange model. Measurements in Arabidopsis thaliana indicated that the Laisk and O2-exchange methods produced similar Γ* at 25 °C; however, Γ* values from O2 exchange were lower at 35 °C compared with the Laisk method. Compared with a photorespiratory mutant (pmdh1pmdh2hpr) with increased α, wild-type (WT) plants had lower Laisk values of Γ* at 25 °C but were not significantly different at 35 °C. These differences between Laisk and O2 exchange values of Γ* at 35 °C could be explained by temperature sensitivity of α in WT and/or errors in the assumptions of O2 exchange. The differences between Γ* measured using the Laisk and O2-exchange method with temperature demonstrate that assumptions used to measure Γ*, and possibly the species-specific validity of these assumptions, need to be considered when modelling the temperature response of photosynthesis.

The Matchmaker Exchange API: automating patient matching through the exchange of structured phenotypic and genotypic profiles

PubMed Central

Buske, Orion J.; Schiettecatte, François; Hutton, Benjamin; Dumitriu, Sergiu; Misyura, Andriy; Huang, Lijia; Hartley, Taila; Girdea, Marta; Sobreira, Nara; Mungall, Chris; Brudno, Michael

2016-01-01

Despite the increasing prevalence of clinical sequencing, the difficulty of identifying additional affected families is a key obstacle to solving many rare diseases. There may only be a handful of similar patients worldwide, and their data may be stored in diverse clinical and research databases. Computational methods are necessary to enable finding similar patients across the growing number of patient repositories and registries. We present the Matchmaker Exchange Application Programming Interface (MME API), a protocol and data format for exchanging phenotype and genotype profiles to enable matchmaking among patient databases, facilitate the identification of additional cohorts, and increase the rate with which rare diseases can be researched and diagnosed. We designed the API to be straightforward and flexible in order to simplify its adoption on a large number of data types and workflows. We also provide a public test data set, curated from the literature, to facilitate implementation of the API and development of new matching algorithms. The initial version of the API has been successfully implemented by three members of the Matchmaker Exchange and was immediately able to reproduce previously-identified matches and generate several new leads currently being validated. The API is available at https://github.com/ga4gh/mme-apis. PMID:26255989

Cast and 3D printed ion exchange membranes for monolithic microbial fuel cell fabrication

NASA Astrophysics Data System (ADS)

Philamore, Hemma; Rossiter, Jonathan; Walters, Peter; Winfield, Jonathan; Ieropoulos, Ioannis

2015-09-01

We present novel solutions to a key challenge in microbial fuel cell (MFC) technology; greater power density through increased relative surface area of the ion exchange membrane that separates the anode and cathode electrodes. The first use of a 3D printed polymer and a cast latex membrane are compared to a conventionally used cation exchange membrane. These new techniques significantly expand the geometric versatility available to ion exchange membranes in MFCs, which may be instrumental in answering challenges in the design of MFCs including miniaturisation, cost and ease of fabrication. Under electrical load conditions selected for optimal power transfer, peak power production (mean 10 batch feeds) was 11.39 μW (CEM), 10.51 μW (latex) and 0.92 μW (Tangoplus). Change in conductivity and pH of anolyte were correlated with MFC power production. Digital and environmental scanning electron microscopy show structural changes to and biological precipitation on membrane materials following long term use in an MFC. The cost of the novel membranes was lower than the conventional CEM. The efficacy of two novel membranes for ion exchange indicates that further characterisation of these materials and their fabrication techniques, shows great potential to significantly increase the range and type of MFCs that can be produced.

Cerebral arterial pulsation drives paravascular CSF-interstitial fluid exchange in the murine brain.

PubMed

Iliff, Jeffrey J; Wang, Minghuan; Zeppenfeld, Douglas M; Venkataraman, Arun; Plog, Benjamin A; Liao, Yonghong; Deane, Rashid; Nedergaard, Maiken

2013-11-13

CSF from the subarachnoid space moves rapidly into the brain along paravascular routes surrounding penetrating cerebral arteries, exchanging with brain interstitial fluid (ISF) and facilitating the clearance of interstitial solutes, such as amyloid β, in a pathway that we have termed the "glymphatic" system. Prior reports have suggested that paravascular bulk flow of CSF or ISF may be driven by arterial pulsation. However, cerebral arterial pulsation could not be directly assessed. In the present study, we use in vivo two-photon microscopy in mice to visualize vascular wall pulsatility in penetrating intracortical arteries. We observed that unilateral ligation of the internal carotid artery significantly reduced arterial pulsatility by ~50%, while systemic administration of the adrenergic agonist dobutamine increased pulsatility of penetrating arteries by ~60%. When paravascular CSF-ISF exchange was evaluated in real time using in vivo two-photon and ex vivo fluorescence imaging, we observed that internal carotid artery ligation slowed the rate of paravascular CSF-ISF exchange, while dobutamine increased the rate of paravascular CSF-ISF exchange. These findings demonstrate that cerebral arterial pulsatility is a key driver of paravascular CSF influx into and through the brain parenchyma, and suggest that changes in arterial pulsatility may contribute to accumulation and deposition of toxic solutes, including amyloid β, in the aging brain.

The Matchmaker Exchange API: automating patient matching through the exchange of structured phenotypic and genotypic profiles.

PubMed

Buske, Orion J; Schiettecatte, François; Hutton, Benjamin; Dumitriu, Sergiu; Misyura, Andriy; Huang, Lijia; Hartley, Taila; Girdea, Marta; Sobreira, Nara; Mungall, Chris; Brudno, Michael

2015-10-01

Despite the increasing prevalence of clinical sequencing, the difficulty of identifying additional affected families is a key obstacle to solving many rare diseases. There may only be a handful of similar patients worldwide, and their data may be stored in diverse clinical and research databases. Computational methods are necessary to enable finding similar patients across the growing number of patient repositories and registries. We present the Matchmaker Exchange Application Programming Interface (MME API), a protocol and data format for exchanging phenotype and genotype profiles to enable matchmaking among patient databases, facilitate the identification of additional cohorts, and increase the rate with which rare diseases can be researched and diagnosed. We designed the API to be straightforward and flexible in order to simplify its adoption on a large number of data types and workflows. We also provide a public test data set, curated from the literature, to facilitate implementation of the API and development of new matching algorithms. The initial version of the API has been successfully implemented by three members of the Matchmaker Exchange and was immediately able to reproduce previously identified matches and generate several new leads currently being validated. The API is available at https://github.com/ga4gh/mme-apis. © 2015 WILEY PERIODICALS, INC.

Reliable oligonucleotide conformational ensemble generation in explicit solvent for force field assessment using reservoir replica exchange molecular dynamics simulations

PubMed Central

Henriksen, Niel M.; Roe, Daniel R.; Cheatham, Thomas E.

2013-01-01

Molecular dynamics force field development and assessment requires a reliable means for obtaining a well-converged conformational ensemble of a molecule in both a time-efficient and cost-effective manner. This remains a challenge for RNA because its rugged energy landscape results in slow conformational sampling and accurate results typically require explicit solvent which increases computational cost. To address this, we performed both traditional and modified replica exchange molecular dynamics simulations on a test system (alanine dipeptide) and an RNA tetramer known to populate A-form-like conformations in solution (single-stranded rGACC). A key focus is on providing the means to demonstrate that convergence is obtained, for example by investigating replica RMSD profiles and/or detailed ensemble analysis through clustering. We found that traditional replica exchange simulations still require prohibitive time and resource expenditures, even when using GPU accelerated hardware, and our results are not well converged even at 2 microseconds of simulation time per replica. In contrast, a modified version of replica exchange, reservoir replica exchange in explicit solvent, showed much better convergence and proved to be both a cost-effective and reliable alternative to the traditional approach. We expect this method will be attractive for future research that requires quantitative conformational analysis from explicitly solvated simulations. PMID:23477537

Reliable oligonucleotide conformational ensemble generation in explicit solvent for force field assessment using reservoir replica exchange molecular dynamics simulations.

PubMed

Henriksen, Niel M; Roe, Daniel R; Cheatham, Thomas E

2013-04-18

Molecular dynamics force field development and assessment requires a reliable means for obtaining a well-converged conformational ensemble of a molecule in both a time-efficient and cost-effective manner. This remains a challenge for RNA because its rugged energy landscape results in slow conformational sampling and accurate results typically require explicit solvent which increases computational cost. To address this, we performed both traditional and modified replica exchange molecular dynamics simulations on a test system (alanine dipeptide) and an RNA tetramer known to populate A-form-like conformations in solution (single-stranded rGACC). A key focus is on providing the means to demonstrate that convergence is obtained, for example, by investigating replica RMSD profiles and/or detailed ensemble analysis through clustering. We found that traditional replica exchange simulations still require prohibitive time and resource expenditures, even when using GPU accelerated hardware, and our results are not well converged even at 2 μs of simulation time per replica. In contrast, a modified version of replica exchange, reservoir replica exchange in explicit solvent, showed much better convergence and proved to be both a cost-effective and reliable alternative to the traditional approach. We expect this method will be attractive for future research that requires quantitative conformational analysis from explicitly solvated simulations.

Ocean processes at the Antarctic continental slope

PubMed Central

Heywood, Karen J.; Schmidtko, Sunke; Heuzé, Céline; Kaiser, Jan; Jickells, Timothy D.; Queste, Bastien Y.; Stevens, David P.; Wadley, Martin; Thompson, Andrew F.; Fielding, Sophie; Guihen, Damien; Creed, Elizabeth; Ridley, Jeff K.; Smith, Walker

2014-01-01

The Antarctic continental shelves and slopes occupy relatively small areas, but, nevertheless, are important for global climate, biogeochemical cycling and ecosystem functioning. Processes of water mass transformation through sea ice formation/melting and ocean–atmosphere interaction are key to the formation of deep and bottom waters as well as determining the heat flux beneath ice shelves. Climate models, however, struggle to capture these physical processes and are unable to reproduce water mass properties of the region. Dynamics at the continental slope are key for correctly modelling climate, yet their small spatial scale presents challenges both for ocean modelling and for observational studies. Cross-slope exchange processes are also vital for the flux of nutrients such as iron from the continental shelf into the mixed layer of the Southern Ocean. An iron-cycling model embedded in an eddy-permitting ocean model reveals the importance of sedimentary iron in fertilizing parts of the Southern Ocean. Ocean gliders play a key role in improving our ability to observe and understand these small-scale processes at the continental shelf break. The Gliders: Excellent New Tools for Observing the Ocean (GENTOO) project deployed three Seagliders for up to two months in early 2012 to sample the water to the east of the Antarctic Peninsula in unprecedented temporal and spatial detail. The glider data resolve small-scale exchange processes across the shelf-break front (the Antarctic Slope Front) and the front's biogeochemical signature. GENTOO demonstrated the capability of ocean gliders to play a key role in a future multi-disciplinary Southern Ocean observing system. PMID:24891389

The Emerging Relationship Between Interstitial Fluid-Cerebrospinal Fluid Exchange, Amyloid-β, and Sleep.

PubMed

Boespflug, Erin L; Iliff, Jeffrey J

2018-02-15

Amyloid-β (Aβ) plaques are a key histopathological hallmark of Alzheimer's disease (AD), and soluble Aβ species are believed to play an important role in the clinical development of this disease. Emerging biomarker data demonstrate that Aβ plaque deposition begins decades before the onset of clinical symptoms, suggesting that understanding the biological determinants of the earliest steps in the development of AD pathology may provide key opportunities for AD treatment and prevention. Although a clinical association between sleep disruption and AD has long been appreciated, emerging clinical studies and insights from the basic neurosciences have shed important new light on how sleep and Aβ homeostasis may be connected in the setting of AD. Aβ, like many interstitial solutes, is cleared in part through the exchange of brain interstitial fluid and cerebrospinal fluid along a brain-wide network of perivascular pathways recently termed the glymphatic system. Glymphatic function is primarily a feature of the sleeping brain, rather than the waking brain, and is slowed in the aging and posttraumatic brain. These changes may underlie the diurnal fluctuations in interstitial and cerebrospinal fluid Aβ levels observed in both the rodent and the human. These and other emerging studies suggest that age-related sleep disruption may be one key factor that renders the aging brain vulnerable to Aβ deposition and the development of AD. If this is true, sleep may represent a key modifiable risk factor or therapeutic target in the preclinical phases of AD. Copyright © 2017 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Ocean processes at the Antarctic continental slope.

PubMed

Heywood, Karen J; Schmidtko, Sunke; Heuzé, Céline; Kaiser, Jan; Jickells, Timothy D; Queste, Bastien Y; Stevens, David P; Wadley, Martin; Thompson, Andrew F; Fielding, Sophie; Guihen, Damien; Creed, Elizabeth; Ridley, Jeff K; Smith, Walker

2014-07-13

The Antarctic continental shelves and slopes occupy relatively small areas, but, nevertheless, are important for global climate, biogeochemical cycling and ecosystem functioning. Processes of water mass transformation through sea ice formation/melting and ocean-atmosphere interaction are key to the formation of deep and bottom waters as well as determining the heat flux beneath ice shelves. Climate models, however, struggle to capture these physical processes and are unable to reproduce water mass properties of the region. Dynamics at the continental slope are key for correctly modelling climate, yet their small spatial scale presents challenges both for ocean modelling and for observational studies. Cross-slope exchange processes are also vital for the flux of nutrients such as iron from the continental shelf into the mixed layer of the Southern Ocean. An iron-cycling model embedded in an eddy-permitting ocean model reveals the importance of sedimentary iron in fertilizing parts of the Southern Ocean. Ocean gliders play a key role in improving our ability to observe and understand these small-scale processes at the continental shelf break. The Gliders: Excellent New Tools for Observing the Ocean (GENTOO) project deployed three Seagliders for up to two months in early 2012 to sample the water to the east of the Antarctic Peninsula in unprecedented temporal and spatial detail. The glider data resolve small-scale exchange processes across the shelf-break front (the Antarctic Slope Front) and the front's biogeochemical signature. GENTOO demonstrated the capability of ocean gliders to play a key role in a future multi-disciplinary Southern Ocean observing system.

Professional Development. The Evaluation Exchange. Volume 11, Number 4, Winter 2005-2006

ERIC Educational Resources Information Center

DeDeo, Carrie-Anne, Ed.

2006-01-01

This issue hones in on professional development in four key sectors affecting children, youth, and families--K-12 education, early childhood education, child welfare, and youth development. Though these sectors face many of the same professional development challenges, each has its own unique issues, strengths, and goals. The staffing shortage in…

Tree ecophysiology research at Taylor Woods

Treesearch

Thomas E. Kolb; Nate G. McDowell

2008-01-01

We summarize the key findings of tree ecophysiology studies performed at Taylor Woods, Fort Valley Experimental Forest, Arizona between 1994 and 2003 that provide unique insight on impacts of long-term stand density management in ponderosa pine forests on tree water relations, leaf gas exchange, radial growth, leaf area-to-sapwood-area ratio, growth efficiency, leaf...

77 FR 34431 - Self-Regulatory Organizations; BATS Y-Exchange, Inc.; Notice of Filing and Immediate...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-11

... contracts and all customer and introducing broker proprietary accounts along with key personnel to Apex Clearing (the ``Transferring Accounts'').\\5\\ \\4\\ Prior to the Transaction, Apex Clearing's name was Ridge... Transferring Accounts by PFSI. On May 31, 2012, Apex Clearing submitted an application for approval as an...

Teaching Financial Literacy with Max and Ruby

ERIC Educational Resources Information Center

Brown, Natalya; Ferguson, Kristen

2017-01-01

Teaching financial literacy is important at all stages of life, but is often neglected with elementary students. In this article, the authors describe a strategy for teaching financial literacy using the books about Max and Ruby by Rosemary Wells. These books can help introduce the five key concepts of financial literacy: scarcity, exchange,…

Final report for the National Center for Intermodal Transportation for Economic Competitiveness : project title: student technology exchange program (STEP) for engineering/robotics in middle school students.

DOT National Transportation Integrated Search

2015-05-05

Key outcomes or other achievements - This project highlighted the importance of math and science concepts within three of the six STEM-related career clusters as defined by the Mississippi Department of Education: Agriculture, Food and Natural Resour...

Knowledge Management in Sustainability Research Projects: Concepts, Effective Models, and Examples in a Multi-Stakeholder Environment

ERIC Educational Resources Information Center

Kaiser, David Brian; Köhler, Thomas; Weith, Thomas

2016-01-01

This article aims to sketch a conceptual design for an information and knowledge management system in sustainability research projects. The suitable frameworks to implement knowledge transfer models constitute social communities, because the mutual exchange and learning processes among all stakeholders promote key sustainable developments through…

Carbon use and uptake efficiencies of hayed alfalfa and grassland in a semiarid environment

USDA-ARS?s Scientific Manuscript database

Land use and management practices are key factors that influence net ecosystem exchange (NEE) for carbon dioxide in semiarid regions. We used alfalfa (Medicago sativa L.) and grassland ecosystems in a multi-year study (2009-2013) to determine the daily, seasonal and annual carbon (C) budget, and par...

Ontology-Based Peer Exchange Network (OPEN)

ERIC Educational Resources Information Center

Dong, Hui

2010-01-01

In current Peer-to-Peer networks, distributed and semantic free indexing is widely used by systems adopting "Distributed Hash Table" ("DHT") mechanisms. Although such systems typically solve a. user query rather fast in a deterministic way, they only support a very narrow search scheme, namely the exact hash key match. Furthermore, DHT systems put…

The Influence of the Knowledge Society: Trends in Adult Higher Education

ERIC Educational Resources Information Center

Kasworm, Carol

2011-01-01

Current understandings of a knowledge economy have been emerging from two defining forces: the rise in quality and intensity of knowledge as a key commodity for economic development and the increasing globalization through information technology of both knowledge exchange and economic activities. The future of adult higher education is focused on…

Automatic Classification of Question & Answer Discourse Segments from Teacher's Speech in Classrooms

ERIC Educational Resources Information Center

Blanchard, Nathaniel; D'Mello, Sidney; Olney, Andrew M.; Nystrand, Martin

2015-01-01

Question-answer (Q&A) is fundamental for dialogic instruction, an important pedagogical technique based on the free exchange of ideas and open-ended discussion. Automatically detecting Q&A is key to providing teachers with feedback on appropriate use of dialogic instructional strategies. In line with this, this paper studies the…

Physical Space and the Resource-Based View of the College

ERIC Educational Resources Information Center

Fugazzotto, Sam J.

2010-01-01

Space serves as a key resource for colleges and universities, and institutions exchange information about it with each other and with prospective students. Using content analysis to examine several widely circulated publications, this study looked for differences in the value attributed to space when institutional leaders present it to students…

Quality Assurance and Qualifications Frameworks: Exchanging Good Practice. ENQA Workshop Report 21

ERIC Educational Resources Information Center

Blomqvist, Carita; Donohoe, Tony; Kelo, Maria; Linde, Karin Jarplid; Llavori, Rafael; Maguire, Bryan; Metz, David; Sanchez, Teresa

2012-01-01

The theme of qualifications frameworks and their relation to quality assurance is gaining urgency in the European scene as more and more countries are completing their national qualifications frameworks and quality assurance agencies need to take important decisions on how to implement them. Some of the key features of the qualifications…

Social Exchange and the Progression of Sexual Relationships in Emerging Adulthood

ERIC Educational Resources Information Center

Sassler, Sharon; Joyner, Kara

2011-01-01

Research has extensively examined matching on race and other characteristics in cohabitation and marriage, but it has generally disregarded sexual and romantic relationships. Using data from the 2002 National Survey of Family Growth and the National Longitudinal Study of Adolescent Health, we examine the tempo of key transitions in the recent…

International Study Tours: A Key to 21st Century Academic and Industry Exchanges

ERIC Educational Resources Information Center

Hol, Ana; Simiana, Danielle; Lieu, Gilbert; Ong, Ivan; Feder, Josh; Dawre, Nimat; Almazi, Wakil

2016-01-01

This paper is based on the retrospective reviews of the Information Systems study group who went on the international study tour to India to learn, network and collaborate with academics, students and industry professionals overseas. The paper addresses concerns of local Australian Science, Technology, Engineering and Mathematics recruiters and…

Surface Carbonization of GaN and the Related Structure Evolution during the Annealing Process

NASA Astrophysics Data System (ADS)

Liu, Jin-Long; Chen, Liang-Xian; Wei, Jun-Jun; Hei, Li-Fu; Zhang, Xu; Li, Cheng-Ming

2018-01-01

Not Available Supported by the National Natural Science Foundation of China under Grant No 51402013, the National Key Research and Development Program of China under Grant No 2016YFE0133200, and the European Union’s Horizon 2020 Research and Innovation Staff Exchange Scheme under Grant No 734578.

Key Components of Collaborative Research in the Context of Environmental Health: A Scoping Review

ERIC Educational Resources Information Center

Wine, Osnat; Ambrose, Sarah; Campbell, Sandy; Villeneuve, Paul J.; Burns, Katharina Kovacs; Vargas, Alvaro Osornio

2017-01-01

In a collaborative research process, the participation of interdisciplinary researchers and multi-sectoral stakeholders supports the co-creation, translation, and exchange of new knowledge. Following a scoping review methodology, we explored the collaborative research processes in the specific context of environment and human health research.…

Synchronous Chat and Electronic Ink for Distance Support in Mathematics

ERIC Educational Resources Information Center

Loch, Birgit; McDonald, Christine

2007-01-01

For online mathematics instructors, synchronous communication can be a challenge due to the need for specialized symbols, graphics, or notations to explain key concepts. While software tools exist to support such communication, they can often be cumbersome and time-consuming for users to adopt in online exchanges. As one way of addressing this…

Structural landscape of the proline-rich domain of Sos1 nucleotide exchange factor.

PubMed

McDonald, Caleb B; Bhat, Vikas; Kurouski, Dmitry; Mikles, David C; Deegan, Brian J; Seldeen, Kenneth L; Lednev, Igor K; Farooq, Amjad

2013-01-01

Despite its key role in mediating a plethora of cellular signaling cascades pertinent to health and disease, little is known about the structural landscape of the proline-rich (PR) domain of Sos1 guanine nucleotide exchange factor. Herein, using a battery of biophysical tools, we provide evidence that the PR domain of Sos1 is structurally disordered and adopts an extended random coil-like conformation in solution. Of particular interest is the observation that while chemical denaturation of PR domain results in the formation of a significant amount of polyproline II (PPII) helices, it has little or negligible effect on its overall size as measured by its hydrodynamic radius. Our data also show that the PR domain displays a highly dynamic conformational basin in agreement with the knowledge that the intrinsically unstructured proteins rapidly interconvert between an ensemble of conformations. Collectively, our study provides new insights into the conformational equilibrium of a key signaling molecule with important consequences on its physiological function. Copyright © 2013 Elsevier B.V. All rights reserved.

Sodium Bearing Waste Processing Alternatives Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murphy, James Anthony; Palmer, Brent J; Perry, Keith Joseph

2003-12-01

A multidisciplinary team gathered to develop a BBWI recommendation to DOE-ID on the processing alternatives for the sodium bearing waste in the INTEC Tank Farm. Numerous alternatives were analyzed using a rigorous, systematic approach. The data gathered were evaluated through internal and external peer reviews for consistency and validity. Three alternatives were identified to be top performers: Risk-based Calcination, MACT to WIPP Calcination and Cesium Ion Exchange. A dual-path through early Conceptual design is recommended for MACT to WIPP Calcination and Cesium Ion Exchange since Risk-based Calcination does not require design. If calcination alternatives are not considered based on givingmore » Type of Processing criteria significantly greater weight, the CsIX/TRUEX alternative follows CsIX in ranking. However, since CsIX/TRUEX shares common uncertainties with CsIX, reasonable backups, which follow in ranking, are the TRUEX and UNEX alternatives. Key uncertainties must be evaluated by the decision-makers to choose one final alternative. Those key uncertainties and a path forward for the technology roadmapping of these alternatives is provided.« less

The quiet revolution: continuous glider monitoring at ocean 'choke' points as a key component of new cross-platform ocean observation systems

NASA Astrophysics Data System (ADS)

Heslop, E. E.; Tintore, J.; Ruiz, S.; Allen, J.; López-Jurado, J. L.

2014-12-01

A quiet revolution is taking place in ocean observations; in the last decade new multi-platform, integrated ocean observatories have been progressively implemented by forward looking countries with ocean borders of economic and strategic importance. These systems are designed to fill significant gaps in our knowledge of the ocean state and ocean variability, through long-term, science and society-led, ocean monitoring. These ocean observatories are now delivering results, not the headline results of a single issue experiment, but carefully and systematically improving our knowledge of ocean variability, and thereby, increasing model forecast skill and our ability to link physical processes to ecosystem response. Here we present the results from a 3-year quasi-continuous glider monitoring of a key circulation 'choke' point in the Western Mediterranean, undertaken by SOCIB (Balearic Islands Coastal Ocean Observing and Forecasting System). For the first time data from the high frequency glider sampling show variations in the transport volumes of water over timescales of days to weeks, as large as those previously only identifiable as seasonal or eddy driven. Although previous surveys noted high cruise-to-cruise variability, they were insufficient to show that in fact water volumes exchanged through this narrow 'choke' point fluctuate on 'weather' timescales. Using the glider data to leverage an 18-year record of ship missions, we define new seasonal cycles for the exchange of watermasses, challenging generally held assumptions. The pattern of the exchange is further simplified through the characterisation of 5 circulation modes and the defining of a new seasonal cycle for the interplay between mesoscale and basin scale dynamics. Restricted 'choke points' between our ocean basins are critical locations to monitor water transport variability, as they constrain the inter-basin exchange of heat, salt and nutrients. At the Ibiza Channel 'choke' point, the exchange of watermass is known to affect local ecosystems, including the spawning grounds of commercially important fish stocks, at a biodiversity hotspot. This new insight will be vital in improving our ocean model forecast skill and in the development of integrated ocean products for society.

Current issues and uncertainties in the measurement and modelling of air-vegetation exchange and within-plant processing of POPs.

PubMed

Barber, Jonathan L; Thomas, Gareth O; Kerstiens, Gerhard; Jones, Kevin C

2004-01-01

Air-vegetation exchange of POPs is an important process controlling the entry of POPs into terrestrial food chains, and may also have a significant effect on the global movement of these compounds. Many factors affect the air-vegetation transfer including: the physicochemical properties of the compounds of interest; environmental factors such as temperature, wind speed, humidity and light conditions; and plant characteristics such as functional type, leaf surface area, cuticular structure, and leaf longevity. The purpose of this review is to quantify the effects these differences might have on air/plant exchange of POPs, and to point out the major gaps in the knowledge of this subject that require further research. Uptake mechanisms are complicated, with the role of each factor in controlling partitioning, fate and behaviour process still not fully understood. Consequently, current models of air-vegetation exchange do not incorporate variability in these factors, with the exception of temperature. These models instead rely on using average values for a number of environmental factors (e.g. plant lipid content, surface area), ignoring the large variations in these values. The available models suggest that boundary layer conductance is of key importance in the uptake of POPs, although large uncertainties in the cuticular pathway prevents confirmation of this with any degree of certainty, and experimental data seems to show plant-side resistance to be important. Models are usually based on the assumption that POP uptake occurs through the lipophilic cuticle which covers aerial surfaces of plants. However, some authors have recently attached greater importance to the stomatal route of entry into the leaf for gas phase compounds. There is a need for greater mechanistic understanding of air-plant exchange and the 'scaling' of factors affecting it. The review also suggests a number of key variables that researchers should measure in their experiments to allow comparisons to be made between studies in order to improve our understanding of what causes any differences in measured data between sites.

Tight finite-key analysis for quantum cryptography

PubMed Central

Tomamichel, Marco; Lim, Charles Ci Wen; Gisin, Nicolas; Renner, Renato

2012-01-01

Despite enormous theoretical and experimental progress in quantum cryptography, the security of most current implementations of quantum key distribution is still not rigorously established. One significant problem is that the security of the final key strongly depends on the number, M, of signals exchanged between the legitimate parties. Yet, existing security proofs are often only valid asymptotically, for unrealistically large values of M. Another challenge is that most security proofs are very sensitive to small differences between the physical devices used by the protocol and the theoretical model used to describe them. Here we show that these gaps between theory and experiment can be simultaneously overcome by using a recently developed proof technique based on the uncertainty relation for smooth entropies. PMID:22252558

Tight finite-key analysis for quantum cryptography.

PubMed

Tomamichel, Marco; Lim, Charles Ci Wen; Gisin, Nicolas; Renner, Renato

2012-01-17

Despite enormous theoretical and experimental progress in quantum cryptography, the security of most current implementations of quantum key distribution is still not rigorously established. One significant problem is that the security of the final key strongly depends on the number, M, of signals exchanged between the legitimate parties. Yet, existing security proofs are often only valid asymptotically, for unrealistically large values of M. Another challenge is that most security proofs are very sensitive to small differences between the physical devices used by the protocol and the theoretical model used to describe them. Here we show that these gaps between theory and experiment can be simultaneously overcome by using a recently developed proof technique based on the uncertainty relation for smooth entropies.

Faraday-Michelson system for quantum cryptography.

PubMed

Mo, Xiao-Fan; Zhu, Bing; Han, Zheng-Fu; Gui, You-Zhen; Guo, Guang-Can

2005-10-01

Quantum key distribution provides unconditional security for communication. Unfortunately, current experimental schemes are not suitable for long-distance fiber transmission because of phase drift or Rayleigh backscattering. In this Letter we present a unidirectional intrinsically stable scheme that is based on Michelson-Faraday interferometers, in which ordinary mirrors are replaced with 90 degree Faraday mirrors. With the scheme, a demonstration setup was built and excellent stability of interference fringe visibility was achieved over a fiber length of 175 km. Through a 125 km long commercial communication fiber cable between Beijing and Tianjin, the key exchange was performed with a quantum bit-error rate of less than 6%, which is to our knowledge the longest reported quantum key distribution experiment under field conditions.

From science to action: Principles for undertaking environmental research that enables knowledge exchange and evidence-based decision-making.

PubMed

Cvitanovic, C; McDonald, J; Hobday, A J

2016-12-01

Effective conservation requires knowledge exchange among scientists and decision-makers to enable learning and support evidence-based decision-making. Efforts to improve knowledge exchange have been hindered by a paucity of empirically-grounded guidance to help scientists and practitioners design and implement research programs that actively facilitate knowledge exchange. To address this, we evaluated the Ningaloo Research Program (NRP), which was designed to generate new scientific knowledge to support evidence-based decisions about the management of the Ningaloo Marine Park in north-western Australia. Specifically, we evaluated (1) outcomes of the NRP, including the extent to which new knowledge informed management decisions; (2) the barriers that prevented knowledge exchange among scientists and managers; (3) the key requirements for improving knowledge exchange processes in the future; and (4) the core capacities that are required to support knowledge exchange processes. While the NRP generated expansive and multidisciplinary science outputs directly relevant to the management of the Ningaloo Marine Park, decision-makers are largely unaware of this knowledge and little has been integrated into decision-making processes. A range of barriers prevented efficient and effective knowledge exchange among scientists and decision-makers including cultural differences among the groups, institutional barriers within decision-making agencies, scientific outputs that were not translated for decision-makers and poor alignment between research design and actual knowledge needs. We identify a set of principles to be implemented routinely as part of any applied research program, including; (i) stakeholder mapping prior to the commencement of research programs to identify all stakeholders, (ii) research questions to be co-developed with stakeholders, (iii) implementation of participatory research approaches, (iv) use of a knowledge broker, and (v) tailored knowledge management systems. Finally, we articulate the individual, institutional and financial capacities that must be developed to underpin successful knowledge exchange strategies. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Nanomaterials Versus Ambient Ultrafine Particles: An Opportunity to Exchange Toxicology Knowledge

PubMed Central

Miller, Mark R.; Clift, Martin J.D.; Elder, Alison; Mills, Nicholas L.; Møller, Peter; Schins, Roel P.F.; Vogel, Ulla; Kreyling, Wolfgang G.; Alstrup Jensen, Keld; Kuhlbusch, Thomas A.J.; Schwarze, Per E.; Hoet, Peter; Pietroiusti, Antonio; De Vizcaya-Ruiz, Andrea; Baeza-Squiban, Armelle; Teixeira, João Paulo; Tran, C. Lang; Cassee, Flemming R.

2017-01-01

Background: A rich body of literature exists that has demonstrated adverse human health effects following exposure to ambient air particulate matter (PM), and there is strong support for an important role of ultrafine (nanosized) particles. At present, relatively few human health or epidemiology data exist for engineered nanomaterials (NMs) despite clear parallels in their physicochemical properties and biological actions in in vitro models. Objectives: NMs are available with a range of physicochemical characteristics, which allows a more systematic toxicological analysis. Therefore, the study of ultrafine particles (UFP, <100 nm in diameter) provides an opportunity to identify plausible health effects for NMs, and the study of NMs provides an opportunity to facilitate the understanding of the mechanism of toxicity of UFP. Methods: A workshop of experts systematically analyzed the available information and identified 19 key lessons that can facilitate knowledge exchange between these discipline areas. Discussion: Key lessons range from the availability of specific techniques and standard protocols for physicochemical characterization and toxicology assessment to understanding and defining dose and the molecular mechanisms of toxicity. This review identifies a number of key areas in which additional research prioritization would facilitate both research fields simultaneously. Conclusion: There is now an opportunity to apply knowledge from NM toxicology and use it to better inform PM health risk research and vice versa. https://doi.org/10.1289/EHP424 PMID:29017987

Nanomaterials Versus Ambient Ultrafine Particles: An Opportunity to Exchange Toxicology Knowledge.

PubMed

Stone, Vicki; Miller, Mark R; Clift, Martin J D; Elder, Alison; Mills, Nicholas L; Møller, Peter; Schins, Roel P F; Vogel, Ulla; Kreyling, Wolfgang G; Alstrup Jensen, Keld; Kuhlbusch, Thomas A J; Schwarze, Per E; Hoet, Peter; Pietroiusti, Antonio; De Vizcaya-Ruiz, Andrea; Baeza-Squiban, Armelle; Teixeira, João Paulo; Tran, C Lang; Cassee, Flemming R

2017-10-10

A rich body of literature exists that has demonstrated adverse human health effects following exposure to ambient air particulate matter (PM), and there is strong support for an important role of ultrafine (nanosized) particles. At present, relatively few human health or epidemiology data exist for engineered nanomaterials (NMs) despite clear parallels in their physicochemical properties and biological actions in in vitro models. NMs are available with a range of physicochemical characteristics, which allows a more systematic toxicological analysis. Therefore, the study of ultrafine particles (UFP, <100 nm in diameter) provides an opportunity to identify plausible health effects for NMs, and the study of NMs provides an opportunity to facilitate the understanding of the mechanism of toxicity of UFP. A workshop of experts systematically analyzed the available information and identified 19 key lessons that can facilitate knowledge exchange between these discipline areas. Key lessons range from the availability of specific techniques and standard protocols for physicochemical characterization and toxicology assessment to understanding and defining dose and the molecular mechanisms of toxicity. This review identifies a number of key areas in which additional research prioritization would facilitate both research fields simultaneously. There is now an opportunity to apply knowledge from NM toxicology and use it to better inform PM health risk research and vice versa. https://doi.org/10.1289/EHP424.

Social Networks and Community-Based Natural Resource Management

NASA Astrophysics Data System (ADS)

Lauber, T. Bruce; Decker, Daniel J.; Knuth, Barbara A.

2008-10-01

We conducted case studies of three successful examples of collaborative, community-based natural resource conservation and development. Our purpose was to: (1) identify the functions served by interactions within the social networks of involved stakeholders; (2) describe key structural properties of these social networks; and (3) determine how these structural properties varied when the networks were serving different functions. The case studies relied on semi-structured, in-depth interviews of 8 to 11 key stakeholders at each site who had played a significant role in the collaborative projects. Interview questions focused on the roles played by key stakeholders and the functions of interactions between them. Interactions allowed the exchange of ideas, provided access to funding, and enabled some stakeholders to influence others. The exchange of ideas involved the largest number of stakeholders, the highest percentage of local stakeholders, and the highest density of interactions. Our findings demonstrated the value of tailoring strategies for involving stakeholders to meet different needs during a collaborative, community-based natural resource management project. Widespread involvement of local stakeholders may be most appropriate when ideas for a project are being developed. During efforts to exert influence to secure project approvals or funding, however, involving specific individuals with political connections or influence on possible sources of funds may be critical. Our findings are consistent with past work that has postulated that social networks may require specific characteristics to meet different needs in community-based environmental management.

Password-Only Authenticated Three-Party Key Exchange Proven Secure against Insider Dictionary Attacks

PubMed Central

Nam, Junghyun; Choo, Kim-Kwang Raymond

2014-01-01

While a number of protocols for password-only authenticated key exchange (PAKE) in the 3-party setting have been proposed, it still remains a challenging task to prove the security of a 3-party PAKE protocol against insider dictionary attacks. To the best of our knowledge, there is no 3-party PAKE protocol that carries a formal proof, or even definition, of security against insider dictionary attacks. In this paper, we present the first 3-party PAKE protocol proven secure against both online and offline dictionary attacks as well as insider and outsider dictionary attacks. Our construct can be viewed as a protocol compiler that transforms any 2-party PAKE protocol into a 3-party PAKE protocol with 2 additional rounds of communication. We also present a simple and intuitive approach of formally modelling dictionary attacks in the password-only 3-party setting, which significantly reduces the complexity of proving the security of 3-party PAKE protocols against dictionary attacks. In addition, we investigate the security of the well-known 3-party PAKE protocol, called GPAKE, due to Abdalla et al. (2005, 2006), and demonstrate that the security of GPAKE against online dictionary attacks depends heavily on the composition of its two building blocks, namely a 2-party PAKE protocol and a 3-party key distribution protocol. PMID:25309956

Factors influencing consumer adoption of USB-based Personal Health Records in Taiwan

PubMed Central

2012-01-01

Background Usually patients receive healthcare services from multiple hospitals, and consequently their healthcare data are dispersed over many facilities’ paper and electronic-based record systems. Therefore, many countries have encouraged the research on data interoperability, access, and patient authorization. This study is an important part of a national project to build an information exchange environment for cross-hospital digital medical records carried out by the Department of Health (DOH) of Taiwan in May 2008. The key objective of the core project is to set up a portable data exchange environment in order to enable people to maintain and own their essential health information. This study is aimed at exploring the factors influencing behavior and adoption of USB-based Personal Health Records (PHR) in Taiwan. Methods Quota sampling was used, and structured questionnaires were distributed to the outpatient department at ten medical centers which participated in the DOH project to establish the information exchange environment across hospitals. A total of 3000 questionnaires were distributed and 1549 responses were collected, out of those 1465 were valid, accumulating the response rate to 48.83%. Results 1025 out of 1465 respondents had expressed their willingness to apply for the USB-PHR. Detailed analysis of the data reflected that there was a remarkable difference in the “usage intention” between the PHR adopters and non-adopters (χ2 =182.4, p < 0.001). From the result of multivariate logistic regression analyses, we found the key factors affecting patients’ adoption pattern were Usage Intention (OR, 9.43, 95%C.I., 5.87-15.16), Perceived Usefulness (OR, 1.60; 95%C.I., 1.11-2.29) and Subjective Norm (OR, 1.47; 95%C.I., 1.21-1.78). Conclusions Higher Usage Intentions, Perceived Usefulness and Subjective Norm of patients were found to be the key factors influencing PHR adoption. Thus, we suggest that government and hospitals should promote the potential usefulness of PHR, and physicians should encourage patients' to adopt the PHR. PMID:22925029

Carbon speciation at the air-sea interface during rain

NASA Astrophysics Data System (ADS)

McGillis, Wade; Hsueh, Diana; Takeshita, Yui; Donham, Emily; Markowitz, Michele; Turk, Daniela; Martz, Todd; Price, Nicole; Langdon, Chris; Najjar, Raymond; Herrmann, Maria; Sutton, Adrienne; Loose, Brice; Paine, Julia; Zappa, Christopher

2015-04-01

This investigation demonstrates the surface ocean dilution during rain events on the ocean and quantifies the lowering of surface pCO2 affecting the air-sea exchange of carbon dioxide. Surface salinity was measured during rain events in Puerto Rico, the Florida Keys, East Coast USA, Panama, and the Palmyra Atoll. End-member analysis is used to determine the subsequent surface ocean carbonate speciation. Surface ocean carbonate chemistry was measured during rain events to verify any approximations made. The physical processes during rain (cold, fresh water intrusion and buoyancy, surface waves and shear, microscale mixing) are described. The role of rain on surface mixing, biogeochemistry, and air-sea gas exchange will be discussed.

Positron beams and two-photon exchange: The key to precision form factors

NASA Astrophysics Data System (ADS)

Bernauer, Jan C.

2018-05-01

The proton elastic form factor ratio can be measured either via Rosenbluth separation in an unpolarized beam and target experiment, or via the use of polarization degrees of freedom. However, data produced by these two approaches show a discrepancy, increasing with Q2. The proposed explanation of this discrepancy—two-photon exchange—has been tested recently by three experiments. The results support the existence of a small two-photon exchange effect but cannot establish that theoretical treatment at the measured momentum transfers are valid. At larger momentum transfers, theory remains untested. This paper investigates the possibilities of measurements at DESY and Jefferson Lab to measure the effect at larger momentum transfers.

Efficiency reduction and pseudo-convergence in replica exchange sampling of peptide folding unfolding equilibria

NASA Astrophysics Data System (ADS)

Denschlag, Robert; Lingenheil, Martin; Tavan, Paul

2008-06-01

Replica exchange (RE) molecular dynamics (MD) simulations are frequently applied to sample the folding-unfolding equilibria of β-hairpin peptides in solution, because efficiency gains are expected from this technique. Using a three-state Markov model featuring key aspects of β-hairpin folding we show that RE simulations can be less efficient than conventional techniques. Furthermore we demonstrate that one is easily seduced to erroneously assign convergence to the RE sampling, because RE ensembles can rapidly reach long-lived stationary states. We conclude that typical REMD simulations covering a few tens of nanoseconds are by far too short for sufficient sampling of β-hairpin folding-unfolding equilibria.

[AC-STB: dedicated software for managed healthcare of chronic headache patients].

PubMed

Wallasch, T-M; Bek, J; Pabel, R; Modahl, M; Demir, M; Straube, A

2009-04-01

This paper examines a new approach to managed healthcare where a network of care providers exchanges patient information through the internet. Integrating networks of clinical specialists and general care providers promises to achieve qualitative and economic improvements in the German healthcare system. In practice, problems related to patient management and data exchange between the managing clinic and assorted caregivers arise. The implementation and use of a cross-spectrum computerized solution for the management of patients and their care is the key for a successful managed healthcare system. This paper documents the managed healthcare of chronic headache patients and the development of an IT-solution capable of providing distributed patient care and case management.

Wash water reclamation technology for advanced manned spacecraft

NASA Technical Reports Server (NTRS)

Putnam, D. F.

1977-01-01

The results of an analytical study and assessment of state-of-the-art wash water reclamation technology for advanced manned spacecraft is presented. All non-phase-change unit operations, unit processes, and subsystems currently under development by NASA are considered. Included among these are: filtration, ultrafiltration, carbon adsorption, ion exchange, chemical pretreatment, reverse osmosis, hyperfiltration, and certain urea removal techniques. Performance data are given together with the projected weights and sizes of key components and subsystems. In the final assessment, a simple multifiltration approach consisting of surface-type cartridge filters, carbon adsorption and ion exchange resins receives the highest rating for six-man orbital missions of up to 10 years in duration.

Field test of a practical secure communication network with decoy-state quantum cryptography.

PubMed

Chen, Teng-Yun; Liang, Hao; Liu, Yang; Cai, Wen-Qi; Ju, Lei; Liu, Wei-Yue; Wang, Jian; Yin, Hao; Chen, Kai; Chen, Zeng-Bing; Peng, Cheng-Zhi; Pan, Jian-Wei

2009-04-13

We present a secure network communication system that operated with decoy-state quantum cryptography in a real-world application scenario. The full key exchange and application protocols were performed in real time among three nodes, in which two adjacent nodes were connected by approximate 20 km of commercial telecom optical fiber. The generated quantum keys were immediately employed and demonstrated for communication applications, including unbreakable real-time voice telephone between any two of the three communication nodes, or a broadcast from one node to the other two nodes by using one-time pad encryption.

Privacy-enhanced electronic mail

NASA Astrophysics Data System (ADS)

Bishop, Matt

1990-06-01

The security of electronic mail sent through the Internet may be described in exactly three words: there is none. The Privacy and Security Research Group has recommended implementing mechanisms designed to provide security enhancements. The first set of mechanisms provides a protocol to provide privacy, integrity, and authentication for electronic mail; the second provides a certificate-based key management infrastructure to support key distribution throughout the internet, to support the first set of mechanisms. These mechanisms are described, as well as the reasons behind their selection and how these mechanisms can be used to provide some measure of security in the exchange of electronic mail.

Coherent one-way quantum key distribution

NASA Astrophysics Data System (ADS)

Stucki, Damien; Fasel, Sylvain; Gisin, Nicolas; Thoma, Yann; Zbinden, Hugo

2007-05-01

Quantum Key Distribution (QKD) consists in the exchange of a secrete key between two distant points [1]. Even if quantum key distribution systems exist and commercial systems are reaching the market [2], there are still improvements to be made: simplify the construction of the system; increase the secret key rate. To this end, we present a new protocol for QKD tailored to work with weak coherent pulses and at high bit rates [3]. The advantages of this system are that the setup is experimentally simple and it is tolerant to reduced interference visibility and to photon number splitting attacks, thus resulting in a high efficiency in terms of distilled secret bits per qubit. After having successfully tested the feasibility of the system [3], we are currently developing a fully integrated and automated prototype within the SECOQC project [4]. We present the latest results using the prototype. We also discuss the issue of the photon detection, which still remains the bottleneck for QKD.

Kinetics of hydrogen/deuterium exchanges in cometary ices

NASA Astrophysics Data System (ADS)

Faure, Mathilde; Quirico, Eric; Faure, Alexandre; Schmitt, Bernard; Theulé, Patrice; Marboeuf, Ulysse

2015-11-01

The D/H composition of volatile molecules composing cometary ices brings key constraints on the origin of comets, on the extent of their presolar heritage, as well as on the origin of atmospheres and hydrospheres of terrestrial planets. Nevertheless, the D/H composition may have been modified to various extents in the nucleus when a comet approaches the Sun and experiences deep physical and chemical modifications in its subsurface. We question here the evolution of the D/H ratio of organic species by proton exchanges with water ice. We experimentally studied the kinetics of D/H exchanges on the ice mixtures H2O:CD3OD, H2O:CD3ND2 and D2O:HCN. Our results show that fast exchanges occur on the -OH and -NH2 chemical groups, which are processed through hydrogen bonds exchanges with water and by the molecular mobility triggered by structural changes, such as glass transition or crystallization. D/H exchanges kinetic is best described by a second-order kinetic law with activation energies of 4300 ± 900 K and 3300 ± 100 K for H2O:CD3OD and H2O:CD3ND2 ice mixtures, respectively. The corresponding pre-exponential factors ln(A(s-1)) are 25 ± 7 and 20 ± 1, respectively. No exchange was observed in the case of HCN trapped in D2O ice. These results strongly suggest that upon thermal heating (1) -OH and -NH2 chemical groups of any organic molecules loose their primordial D/H composition and equilibrate with water ice, (2) HCN does not experience proton transfer and keeps a primordial D/H composition and (3) C-H chemical groups are not isotopically modified.

Triggering of spin-flipping-modulated exchange bias in FeCo nanoparticles by electronic excitation

PubMed Central

Sarker, Debalaya; Bhattacharya, Saswata; Srivastava, Pankaj; Ghosh, Santanu

2016-01-01

The exchange coupling between ferromagnetic (FM)-antiferromagnetic (AF) interfaces is a key element of modern spintronic devices. We here introduce a new way of triggering exchange bias (EB) in swift heavy ion (SHI) irradiated FeCo-SiO2 films, which is a manifestation of spin-flipping at high irradiation fluence. The elongation of FeCo nanoparticles (NPs) in SiO2 matrix gives rise to perpendicular magnetic anisotropy at intermediate fluence. However, a clear shift in hysteresis loop is evident at the highest fluence. This reveals the existence of an AF exchange pinning domain in the NPs, which is identified not to be oxide shell from XANES analysis. Thermal spike calculations along with first-principles based simulations under the framework of density functional theory (DFT) demonstrate that spin flipping of 3d valence electrons is responsible for formation of these AF domains inside the FM NPs. EXAFS experiments at Fe and Co K-edges further unravel that spin-flipping in highest fluence irradiated film results in reduced bond lengths. The results highlight the possibility of miniaturization of magnetic storage devices by using irradiated NPs instead of conventionally used FM-AF multilayers. PMID:27991552

Semiautomated Sample Preparation for Protein Stability and Formulation Screening via Buffer Exchange.

PubMed

Ying, William; Levons, Jaquan K; Carney, Andrea; Gandhi, Rajesh; Vydra, Vicky; Rubin, A Erik

2016-06-01

A novel semiautomated buffer exchange process workflow was developed to enable efficient early protein formulation screening. An antibody fragment protein, BMSdab, was used to demonstrate the workflow. The process afforded 60% to 80% cycle time and scientist time savings and significant material efficiencies. These efficiencies ultimately facilitated execution of this stability work earlier in the drug development process, allowing this tool to inform the developability of potential candidates for development from a formulation perspective. To overcome the key technical challenges, the protein solution was buffer-exchanged by centrifuge filtration into formulations for stability screening in a 96-well plate with an ultrafiltration membrane, leveraging automated liquid handling and acoustic volume measurements to allow several cycles of exchanges. The formulations were transferred into a vacuum manifold and sterile filtered into a rack holding 96 glass vials. The vials were sealed with a capmat of individual caps and placed in stability stations. Stability of the samples prepared by this process and by the standard process was demonstrated to be comparable. This process enabled screening a number of formulations of a protein at an early pharmaceutical development stage with a short sample preparation time. © 2015 Society for Laboratory Automation and Screening.

Wind-driven circulation patterns in a shallow estuarine lake: St Lucia, South Africa

NASA Astrophysics Data System (ADS)

Schoen, Julia H.; Stretch, Derek D.; Tirok, Katrin

2014-06-01

The spatiotemporal structure of wind-driven circulation patterns and associated water exchanges or residence times can drive important bio-hydrodynamic interactions in shallow lakes and estuaries. The St Lucia estuarine lake in South Africa is an example of such a system. It is a UNESCO World Heritage Site and RAMSAR wetland of international importance but no detailed research on its circulation patterns has previously been undertaken. In this study, a hydrodynamic model was used to investigate the structure of these circulations to provide insights into their role in transport and water exchange processes. A strong diurnal temporal pattern of wind speeds, together with directional switching between two dominant directions, drives intermittent water exchanges and mixing between the lake basins. “High speed flows in shallow nearshore areas with slower upwind counter-flows in deeper areas, linked by circulatory gyres, are key features of the circulation”. These patterns are strongly influenced by the complex geometry of St Lucia and constrictions in the system. Water exchange time scales are non-homogeneous with some basin extremities having relatively long residence times. The influence of the circulation patterns on biological processes is discussed.

Impact of anionic ion exchange resins on NOM fractions: Effect on N-DBPs and C-DBPs precursors.

PubMed

Bazri, Mohammad Mahdi; Martijn, Bram; Kroesbergen, Jan; Mohseni, Madjid

2016-02-01

The formation potential of carbonaceous and nitrogenous disinfection by-products (C-DBPs, N-DBPs) after ion exchange treatment (IEX) of three different water types in multiple consecutive loading cycles was investigated. Liquid chromatography with organic carbon detector (LC-OCD) was employed to gauge the impact of IEX on different natural organic matter (NOM) fractions and data obtained were used to correlate these changes to DBPs Formation Potential (FP) under chlorination. Humic (-like) substances fractions of NOM were mainly targeted by ion exchange resins (40-67% removal), whereas hydrophilic, non-ionic fractions such as neutrals and building blocks were poorly removed during the treatment (12-33% removal). Application of ion exchange resins removed 13-20% of total carbonaceous DBPs FP and 3-50% of total nitrogenous DBPs FP. Effect of the inorganic nitrogen (i.e., Nitrate) presence on N-DBPs FP was insignificant while the presence of dissolved organic nitrogen (DON) was found to be a key parameter affecting the formation of N-DBPs. DON especially the portion affiliated with humic substances fraction, was reduced effectively (∼77%) as a result of IEX treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

A population ecology perspective on the functioning and future of health information organizations.

PubMed

Vest, Joshua R; Menachemi, Nir

2017-11-01

Increasingly, health care providers need to exchange information to meet policy expectations and business needs. A variety of health information organizations (HIOs) provide services to facilitate health information exchange (HIE). However, the future of these organizations is unclear. The aim of this study was to explore the environmental context, potential futures, and survivability of community HIOs, enterprise HIEs, and electronic health record vendor-mediated exchange using the population ecology theory. Qualitative interviews with 33 key informants representing each type of HIE organization were analyzed using template analysis. Community HIOs, enterprise HIEs, and electronic health record vendors exhibited a high degree of competition for resources, especially in the area of exchange infrastructure services. Competition resulted in closures in some areas. In response to environmental pressures, each organizational type was endeavoring to differentiate its services and unique use case, as well as pursing symbiotic relationships or attempting resource partitioning. HIOs compete for similar resources and are reacting to environmental pressures to better position themselves for continued survival and success. Our ecological research perspective helps move the discourse away from situation of a single exchange organization type toward a view of the broader dynamics and relationships of all organizations involved in facilitating HIE activities. HIOs are attempting to partition the environment and differentiate services. HIE options should not be construed as an "either/or" decision, but one where multiple and complementary participation may be required.

A multilevel investigation on nursing turnover intention: the cross-level role of leader-member exchange.

PubMed

Portoghese, Igor; Galletta, Maura; Battistelli, Adalgisa; Leiter, Michael P

2015-09-01

To analyse nursing turnover intention from the unit by using multilevel approach, examining at the individual level, the relationships between job characteristics, job satisfaction and turnover intention, and at the group level the role of leader-member exchange. Research on nursing turnover has given little attention to the effects of multilevel factors. Aggregated data of 935 nurses nested within 74 teams of four Italian hospitals were collected in 2009 via a self-administered questionnaire. Hierarchical linear modelling showed that job satisfaction mediated the relationship between job characteristics and intention to leave at the individual level. At the unit level, leader-member exchange was directly linked to intention to leave. Furthermore, cross-level interaction revealed that leader-member exchange moderated the relationship between job characteristics and job satisfaction. This study supported previous research in single-level turnover studies concerning the key role of job satisfaction, providing evidence that job characteristics are important in creating motivating and satisfying jobs. At the unit-level, leader-member exchange offers an approach to understand the role of unit-specific conditions created by leaders on nurses' workplace wellbeing. This study showed that it is important for nursing managers to recognise the relevance of implementing management practices that foster healthy workplaces centred on high-quality nurse-supervisor relationships. © 2014 John Wiley & Sons Ltd.

The "Fun with Languages" Project: Making Learning Another Language an Early Priority

ERIC Educational Resources Information Center

Saint-Paul, Thérèse; Hendley, Valérie

2016-01-01

There is no denying the importance of multilingualism in the 21st century; increased travels, student exchanges, global business, diplomacy, and security are mediated by communication. Education is the key to building a strong multilingual world community that will work for peace and stability. However, it may be often overlooked that a successful…

Tree ecophysiology research at Taylor Woods (P-53)

Treesearch

Thomas E. Kolb; Nate G. McDowell

2008-01-01

We summarize the key findings of tree ecophysiology studies performed at Taylor Woods, Fort Valley Experimental Forest, Arizona between 1994 and 2003 that provide unique insight on impacts of long-term stand density management in ponderosa pine forests on tree water relations, leaf gas exchange, radial growth, leaf area-to-sapwood-area ratio, growth efficiency, leaf...

A Canonical Correlation Analysis of Social Capital and Knowledge Exchange for Virtual Members of IT Teams

ERIC Educational Resources Information Center

Dutton Feliu, Genevieve

2018-01-01

Social capital theory conceptualized social capital as key to connecting team members into the flow of valued resources and activities, with knowledge deemed one of the most valuable of these resources. Yet, the literature found teams struggle to effectively share knowledge. This quantitative survey-based study assessed the interrelationship…

Gender, Employment and Working Time Preferences in Europe.

ERIC Educational Resources Information Center

Fagan, Colette; Warren, Tracey

A representative survey of over 30,000 people aged 16-64 years across the 15 member states of the European Union and Norway sought Europeans' preferences for increasing or reducing the number of hours worked per week. Key finding included the following: (1) 51% preferred to work fewer hours in exchange for lower earnings while 12% preferred to…

The Perceived and Real Value of Health Information Exchange in Public Health Surveillance

ERIC Educational Resources Information Center

Dixon, Brian Edward

2011-01-01

Public health agencies protect the health and safety of populations. A key function of public health agencies is surveillance or the ongoing, systematic collection, analysis, interpretation, and dissemination of data about health-related events. Recent public health events, such as the H1N1 outbreak, have triggered increased funding for and…

Data-driven diagnostics of terrestrial carbon dynamics over North America

Treesearch

Jingfeng Xiao; Scott V. Ollinger; Steve Frolking; George C. Hurtt; David Y. Hollinger; Kenneth J. Davis; Yude Pan; Xiaoyang Zhang; Feng Deng; Jiquan Chen; Dennis D. Baldocchi; Bevery E. Law; M. Altaf Arain; Ankur R. Desai; Andrew D. Richardson; Ge Sun; Brian Amiro; Hank Margolis; Lianhong Gu; Russell L. Scott; Peter D. Blanken; Andrew E. Suyker

2014-01-01

The exchange of carbon dioxide is a key measure of ecosystem metabolism and a critical intersection between the terrestrial biosphere and the Earth's climate. Despite the general agreement that the terrestrial ecosystems in North America provide a sizeable carbon sink, the size and distribution of the sink remain uncertain. We use a data-driven approach to upscale...

The (Inter)disciplinarity of Media Studies: Pedagogical Challenges and Opportunities From the Perspective of Teaching Staff

ERIC Educational Resources Information Center

Iqani, Mehita; Feigenbaum, Anna

2015-01-01

In a series of Teaching Exchange (TE) staff development workshops aimed at exploring prospective, bottom-up quality assurance in media studies in the United Kingdom, interdisciplinarity arose as a key topic. This article reflects on teaching staff's views expressed in the TE workshops around interdisciplinarity in relation to their experiences in…

Building Capacity for a Global Genome Editing Observatory: Institutional Design.

PubMed

Saha, Krishanu; Hurlbut, J Benjamin; Jasanoff, Sheila; Ahmed, Aziza; Appiah, Anthony; Bartholet, Elizabeth; Baylis, Françoise; Bennett, Gaymon; Church, George; Cohen, I Glenn; Daley, George; Finneran, Kevin; Hurlbut, William; Jaenisch, Rudolf; Lwoff, Laurence; Kimes, John Paul; Mills, Peter; Moses, Jacob; Park, Buhm Soon; Parens, Erik; Salzman, Rachel; Saxena, Abha; Simmet, Hilton; Simoncelli, Tania; Snead, O Carter; Rajan, Kaushik Sunder; Truog, Robert D; Williams, Patricia; Woopen, Christiane

2018-06-08

A new infrastructure is urgently needed at the global level to facilitate exchange on key issues concerning genome editing. We advocate the establishment of a global observatory to serve as a center for international, interdisciplinary, and cosmopolitan reflection. This article is the second of a two-part series. Copyright © 2018 Elsevier Ltd. All rights reserved.

Building Capacity for a Global Genome Editing Observatory: Conceptual Challenges.

PubMed

Hurlbut, J Benjamin; Jasanoff, Sheila; Saha, Krishanu; Ahmed, Aziza; Appiah, Anthony; Bartholet, Elizabeth; Baylis, Françoise; Bennett, Gaymon; Church, George; Cohen, I Glenn; Daley, George; Finneran, Kevin; Hurlbut, William; Jaenisch, Rudolf; Lwoff, Laurence; Kimes, John Paul; Mills, Peter; Moses, Jacob; Park, Buhm Soon; Parens, Erik; Salzman, Rachel; Saxena, Abha; Simmet, Hilton; Simoncelli, Tania; Snead, O Carter; Rajan, Kaushik Sunder; Truog, Robert D; Williams, Patricia; Woopen, Christiane

2018-07-01

A new infrastructure is urgently needed at the global level to facilitate exchange on key issues concerning genome editing. We advocate the establishment of a global observatory to serve as a center for international, interdisciplinary, and cosmopolitan reflection. This article is the first of a two-part series. Copyright © 2018 Elsevier Ltd. All rights reserved.

Using an Outdoor Learning Space to Teach Sustainability and Material Processes in HE Product Design

ERIC Educational Resources Information Center

Firth, Richard; Stoltenberg, Einar; Jennings, Trent

2016-01-01

This "case study" of two jewellery workshops, used outdoor learning spaces to explore both its impact on learning outcomes and to introduce some key principles of sustainable working methodologies and practices. Using the beach as the classroom, academics and students from a Norwegian and Scottish (HE) product design exchange programme…

BIT BY BIT: A Game Simulating Natural Language Processing in Computers

ERIC Educational Resources Information Center

Kato, Taichi; Arakawa, Chuichi

2008-01-01

BIT BY BIT is an encryption game that is designed to improve students' understanding of natural language processing in computers. Participants encode clear words into binary code using an encryption key and exchange them in the game. BIT BY BIT enables participants who do not understand the concept of binary numbers to perform the process of…

ESTIMATION OF LEAF AREA INDEX IN OPEN-CANOPY PONDEROSA PINE FORESTS AT DIFFERENT SUCCESSIONAL STAGES AND MANAGEMENT REGIMES IN OREGON. (R828309)

EPA Science Inventory

Abstract

Leaf area and its spatial distribution are key parameters in describing canopy characteristics. They determine radiation regimes and influence mass and energy exchange with the atmosphere. The evaluation of leaf area in conifer stands is particularly challengi...

Risky Choice in Pigeons: Preference for Amount Variability Using a Token-Reinforcement System

ERIC Educational Resources Information Center

Lagorio, Carla H.; Hackenberg, Timothy D.

2012-01-01

Pigeons were given repeated choices between variable and fixed numbers of token reinforcers (stimulus lamps arrayed above the response keys), with each earned token exchangeable for food. The number of tokens provided by the fixed-amount option remained constant within blocks of sessions, but varied parametrically across phases, assuming values of…

Discrete return lidar-based prediction of leaf area index in two conifer forests

Treesearch

Jennifer L. R. Jensen; Karen S. Humes; Lee A. Vierling; Andrew T. Hudak

2008-01-01

Leaf area index (LAI) is a key forest structural characteristic that serves as a primary control for exchanges of mass and energy within a vegetated ecosystem. Most previous attempts to estimate LAI from remotely sensed data have relied on empirical relationships between field-measured observations and various spectral vegetation indices (SVIs) derived from optical...

An Atlantic Crossing? The Work of the International Examination Inquiry, Its Researchers, Methods and Influence

ERIC Educational Resources Information Center

Lawn, Martin, Ed.

2008-01-01

This book focuses on the International Examinations Inquiry (IEI), an international, well-funded scientific project that operated in the 1930s, attracting key world figures in educational research, and which undertook significant exchanges of data. Originally involving the USA, Scotland, England, France, Germany and Switzerland, the IEI grew to…

Methods of mesophyll conductance estimation: its impact on key biochemical parameters and photosynthetic limitations in phosphorus-stressed soybean across CO2

USDA-ARS?s Scientific Manuscript database

Photosynthetic potential in C3 plants is largely limited by CO2 diffusion through stomata (Ls) and mesophyll (Lm) and photo-biochemical (Lb) processes. Accurate estimation of mesophyll conductance (gm) using gas exchange (GE) and chlorophyll fluorescence (CF) parameters of the photosynthetic proces...

America's Children: Key National Indicators of Well-Being, 2005

ERIC Educational Resources Information Center

Godiwalla, Shara; Schechter, Susan; Simmons, Tavia; Lukacs, Susan; Rooney, Patrick; Axelrad, Daniel; Hawkins, Belinda; Steffen Barry; Harlow, Caroline; Campbell, Jessica; Goldstein, Naomi; Von Ins, Tracy; Morisi, Teri; Wilkinson, Larry

2005-01-01

This report provides the Nation with a summary of national indicators of child well-being and monitors changes in these indicators over time. In addition to providing data in an easy-to-use, non-technical format, the purpose of the report is to stimulate discussions among policymakers and the public, exchanges between data providers and policy…

Bridging the Distance: The Use of Blogs as Reflective Learning Tools for Placement Students

ERIC Educational Resources Information Center

Wolf, Katharina

2010-01-01

This paper reviews the effectiveness of web logs ("blogs"), or online journals, within the context of a compulsory final-year placement unit for public relations students. The key goal behind the use of Web2.0 technology was to encourage ongoing, reflective practice via an exchange between students thereby limiting feelings of isolation…

Comparing ecosystem and soil respiration: Review and key challenges of tower-based and soil mesurements

USDA-ARS?s Scientific Manuscript database

The net ecosystem exchange (NEE) is the difference between ecosystem CO2 assimilation and CO2 losses to the atmosphere. Ecosystem respiration (Reco), the efflux of CO2 from the ecosystem to the atmosphere, includes the soil-to-atmosphere carbon flux (i.e., soil respiration; Rsoil) and aboveground pl...

A "Knowledge Trading Game" for Collaborative Design Learning in an Architectural Design Studio

ERIC Educational Resources Information Center

Wang, Wan-Ling; Shih, Shen-Guan; Chien, Sheng-Fen

2010-01-01

Knowledge-sharing and resource exchange are the key to the success of collaborative design learning. In an architectural design studio, design knowledge entails learning efforts that need to accumulate and recombine dispersed and complementary pieces of knowledge. In this research, firstly, "Knowledge Trading Game" is proposed to be a way for…

Can knowledge exchange support the implementation of a health-promoting schools approach? Perceived outcomes of knowledge exchange in the COMPASS study.

PubMed

Brown, Kristin M; Elliott, Susan J; Robertson-Wilson, Jennifer; Vine, Michelle M; Leatherdale, Scott T

2018-03-13

Despite the potential population-level impact of a health-promoting schools approach, schools face challenges in implementation, indicating a gap between school health research and practice. Knowledge exchange provides an opportunity to reduce this gap; however, there has been limited evaluation of these initiatives. This research explored researchers' and knowledge users' perceptions of outcomes associated with a knowledge exchange initiative within COMPASS, a longitudinal study of Canadian secondary students and schools. Schools received annual tailored summaries of their students' health behaviours and suggestions for action and were linked with knowledge brokers to support them in taking action to improve student health. Qualitative semi-structured interviews were conducted with COMPASS researchers (n = 13), school staff (n = 13), and public health stakeholders (n = 4) to explore their experiences with COMPASS knowledge exchange. Key issues included how knowledge users used school-specific findings, perceived outcomes of knowledge exchange, and suggestions for change. Outcomes for both knowledge users and researchers were identified; interestingly, knowledge users attributed more outcomes to using school-specific findings than knowledge brokering. School and public health participants indicated school-specific findings informed their programming and planning. Importantly, knowledge exchange provided a platform for partnerships between researchers, schools, and public health units. Knowledge brokering allowed researchers to gain feedback from knowledge users to enhance the study and a better understanding of the school environment. Interestingly, COMPASS knowledge exchange outcomes aligned with Samdal and Rowling's eight theory-driven implementation components for health-promoting schools. Hence, knowledge exchange may provide a mechanism to help schools implement a health-promoting schools approach. This research contributes to the limited literature regarding outcomes of knowledge brokering in public health and knowledge exchange in school health research. However, since not all schools engaged in knowledge brokering, and not all schools that engaged discussed these outcomes, further research is needed to determine the amount of engagement required for change and examine the process of COMPASS knowledge brokering to consider how to increase school engagement.

Scaling Hydrologic Exchange Flows and Biogeochemical Reactions from Bedforms to Basins

NASA Astrophysics Data System (ADS)

Harvey, J. W.; Gomez-Velez, J. D.

2015-12-01

River water moves in and out of the main channel along pathways that are perpendicular to the channel's main axis that flow across or beneath the ground surface. These hydrologic exchange flows (HEFs) are difficult to measure, yet no less important than a river's downstream flow, or exchanges with the atmosphere and deeper groundwater (Harvey and Gooseff, 2015, WRR). There are very few comprehensive investigations of exchange fluxes to understand patterns with river size and relative importance of specific types of exchanges. We used the physically based model NEXSS to simulate multiple scales of hyporheic flow and their cumulative effects on solute reaction in large basins (on the order of Chesapeake Bay basin or larger). Our goal was to explain where and when particular types of hyporheic flow are important in enhancing key biogeochemical reactions, such as organic carbon respiration and denitrification. Results demonstrate that hyporheic flux (expressed per unit area of streambed) varies surprisingly little across the continuum of first-order streams to eighth-order rivers, and vertical exchange beneath small bedforms dominates in comparison with lateral flow beneath gravel bars and meanders. Also, the river's entire volume is exchanged many times with hyporheic flow within a basin, and the turnover length (after one entire river volume is exchanged) is strongly influenced by hydrogeomorphic differences between physiographic regions as well as by river size. The cumulative effects on biogeochemical reactions were assessed using a the reaction significance factor, RSF, which computes the cumulative potential for hyporheic reactions using a dimensionless index that balances reaction progress in a single hyporheic flow path against overall processing efficiency of river turnover through hyporheic flow paths of that type. Reaction significance appears to be strongly dominated by hydrologic factors rather than biogeochemical factors, and seems to be dominated by vertical exchange beneath small bedforms throughout river networks. Future implementations of NEXSS will expand the model to consider flow variation and to consider HEFs beyond hyporheic flow to include exchange with marginal surface waters such as riparian wetlands, floodplains, and ponded water.

Patents on Membranes Based on Non-Fluorinated Polymers for Vanadium Redox Flow Batteries.

PubMed

Choi, So-Won; Kim, Tae-Ho; Cha, Sang-Ho

2017-07-10

Vanadium redox flow batteries (VRFBs) have received considerable attention as large-scale electrochemical energy storage systems. In particular, VRFBs offer a higher power and energy density than other RFBs and mitigate undesirable performance fading, such as inevitable ion crossover, because of the unique advantage that only the vanadium ion is employed as the active species in the two electrolytes. The key constituent of VRFBs is a separator to conduct protons and prevent cross-mixing of the positive and negative electrolytes. For this purpose, ion exchange membranes like sulfonated polymer membranes can be used. Although this type of membrane does not have ion exchange groups, it can achieve an ion exchange capacity by the formation of pores. This review highlights the patents on the preparation of non-fluorinated membranes (sulfonated aromatic polymer membranes and porous membranes) as alternatives to high-cost perfluorinated polymers and their VRFB performance. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Help seeking in older Asian people with dementia in Melbourne: using the Cultural Exchange Model to explore barriers and enablers.

PubMed

Haralambous, Betty; Dow, Briony; Tinney, Jean; Lin, Xiaoping; Blackberry, Irene; Rayner, Victoria; Lee, Sook-Meng; Vrantsidis, Freda; Lautenschlager, Nicola; Logiudice, Dina

2014-03-01

The prevalence of dementia is increasing in Australia. Limited research is available on access to Cognitive Dementia and Memory Services (CDAMS) for people with dementia from Culturally and Linguistically Diverse (CALD) communities. This study aimed to determine the barriers and enablers to accessing CDAMS for people with dementia and their families of Chinese and Vietnamese backgrounds. Consultations with community members, community workers and health professionals were conducted using the "Cultural Exchange Model" framework. For carers, barriers to accessing services included the complexity of the health system, lack of time, travel required to get to services, language barriers, interpreters and lack of knowledge of services. Similarly, community workers and health professionals identified language, interpreters, and community perceptions as key barriers to service access. Strategies to increase knowledge included providing information via radio, printed material and education in community group settings. The "Cultural Exchange Model" enabled engagement with and modification of the approaches to meet the needs of the targeted CALD communities.

Key issues in theoretical and functional pneumatic design

NASA Astrophysics Data System (ADS)

Xu, Z. G.; Yang, D. Y.; Liu, W. M.; Liu, T. T.

2017-10-01

This paper studies the energy release of the pneumatic engine in different thermodynamic processes, the isothermal process is the highest power output process, while adiabatic process is the lowest energy output process, and the energy release of the pneumatic engine is a multi-state thermodynamic process between them. Therefore heat exchanging should be increased between the pneumatic engine and the outer space, the gas expansion process in the cylinder should be as close as possible to the isothermal process. Heat exchange should be increased between the cylinder and the external spaces. Secondly, the fin structure is studied to increase the heat exchanging between the cylinder body and the outside space. The upper part has fin structures and the lower cylinder has no fin structure, this structure improved the working efficiency of pneumatic engine. Finally the cam and the hydraulic bottle of pneumatic engines are designed. Simulation and theoretical calculation are used to the analysis of the whole structure, which lay the foundation for the manufacturing and design of the pneumatic engines.

Using Ontologies to Formalize Services Specifications in Multi-Agent Systems

NASA Technical Reports Server (NTRS)

Breitman, Karin Koogan; Filho, Aluizio Haendchen; Haeusler, Edward Hermann

2004-01-01

One key issue in multi-agent systems (MAS) is their ability to interact and exchange information autonomously across applications. To secure agent interoperability, designers must rely on a communication protocol that allows software agents to exchange meaningful information. In this paper we propose using ontologies as such communication protocol. Ontologies capture the semantics of the operations and services provided by agents, allowing interoperability and information exchange in a MAS. Ontologies are a formal, machine processable, representation that allows to capture the semantics of a domain and, to derive meaningful information by way of logical inference. In our proposal we use a formal knowledge representation language (OWL) that translates into Description Logics (a subset of first order logic), thus eliminating ambiguities and providing a solid base for machine based inference. The main contribution of this approach is to make the requirements explicit, centralize the specification in a single document (the ontology itself), at the same that it provides a formal, unambiguous representation that can be processed by automated inference machines.

Management of laboratory data and information exchange in the electronic health record.

PubMed

Wilkerson, Myra L; Henricks, Walter H; Castellani, William J; Whitsitt, Mark S; Sinard, John H

2015-03-01

In the era of the electronic health record, the success of laboratories and pathologists will depend on effective presentation and management of laboratory information, including test orders and results, and effective exchange of data between the laboratory information system and the electronic health record. In this third paper of a series that explores empowerment of pathology in the era of the electronic health record, we review key elements of managing laboratory information within the electronic health record and examine functional issues pertinent to pathologists and laboratories in the exchange of laboratory information between electronic health records and both anatomic and clinical pathology laboratory information systems. Issues with electronic order-entry and results-reporting interfaces are described, and considerations for setting up these interfaces are detailed in tables. The role of the laboratory medical director as mandated by the Clinical Laboratory Improvement Amendments of 1988 and the impacts of discordance between laboratory results and their display in the electronic health record are also discussed.

The effect of ionic membrane properties on the performance of ionic polymer-metal composite (IPMC) actuator

NASA Astrophysics Data System (ADS)

Jho, Jae Y.; Han, Man J.; Park, Jong H.; Lee, Jang Y.; Wang, Hyuck S.

2005-05-01

On purpose to overcome the limit of conventional ionic polymer-metal composites (IPMC) using the commercial ionic membranes, novel IPMCs with radiation-grafted ion-exchange membranes were prepared. Poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-co-HFP) and poly(ethylene-co-tetrafluoroethylene) (ETFE) were radiation-grafted with styrene, and then sulfonated. The properties of the membranes were modulated by controlling the amount of polystyrene sulfonic acid (PSSA) groups in the membranes. The amount of PSSA groups were tuned by controlling the total absorbed dose of γ-ray. The membranes were characterized by measuring the water-uptake, the ion-exchange capacity, and the ion conductivity. The performance of the IPMCs using these membranes were analyzed with laser displacement meter. They exhibited much larger bending displacement in comparison with Nafion-based IPMC. With increasing the amount of PSSA groups, the maximum displacement and the bending speed were remarkably increased. The results made sure that the property of ion-exchange membrane was the key element affecting the actuation performance of IPMC.

Mapping transiently formed and sparsely populated conformations on a complex energy landscape

PubMed Central

Wang, Yong; Papaleo, Elena; Lindorff-Larsen, Kresten

2016-01-01

Determining the structures, kinetics, thermodynamics and mechanisms that underlie conformational exchange processes in proteins remains extremely difficult. Only in favourable cases is it possible to provide atomic-level descriptions of sparsely populated and transiently formed alternative conformations. Here we benchmark the ability of enhanced-sampling molecular dynamics simulations to determine the free energy landscape of the L99A cavity mutant of T4 lysozyme. We find that the simulations capture key properties previously measured by NMR relaxation dispersion methods including the structure of a minor conformation, the kinetics and thermodynamics of conformational exchange, and the effect of mutations. We discover a new tunnel that involves the transient exposure towards the solvent of an internal cavity, and show it to be relevant for ligand escape. Together, our results provide a comprehensive view of the structural landscape of a protein, and point forward to studies of conformational exchange in systems that are less characterized experimentally. DOI: http://dx.doi.org/10.7554/eLife.17505.001 PMID:27552057

A comprehensive model of ion diffusion and charge exchange in the cold Io torus

NASA Technical Reports Server (NTRS)

Barbosa, D. D.; Moreno, M. A.

1988-01-01

A comprehensive analytic model of radial diffusion in the cold Io torus is developed. The model involves a generalized molecular cloud theory of SO2 and its dissociation fragments SO, O2, S, and O, which are formed at a relatively large rate by solar UV photodissociation of SO2. The key component of the new theory is SO, which can react with S(+) through a near-resonant charge exchange process that is exothermic. This provides a mechanism for the rapid depletion of singly ionized sulfur in the cold torus and can account for the large decrease in the total flux tube content inward of Io's orbit. The model is used to demonstrate quantitatively the effects of radial diffusion in a charge exchange environment that acts as a combined source and sink for ions in various charge states. A detailed quantitative explanation for the O(2+) component of the cold torus is given, and insight is derived into the workings of the so-called plasma 'ribbon'.

Studies of giant magnetoresistance and interfacial structure in Cu/Co and Co/Re multilayers

NASA Astrophysics Data System (ADS)

Setty, Arun; Fernando, G.; Cooper, B. R.

2003-03-01

A study of giant magnetoresistance (GMR) in the Cu/Co [1]and Co/Re multilayer [2,3] systems is presented. The role of interface structure in such systems is significant, and is being investigated using an ab-initio based approach [4]. The role of intermixing [5], impurities and growth textures have been considered. Structural relaxation is taken into account using Hellman-Feynman and symmetry-based approaches. We find lattice spacings in agreement with experiment, energetically establish the favored growth textures and find results motivating the existence of the observed wavy interface in the Cu/Co system [6]. The transport properties of these multilayer systems will be studied using a theoretical model [7] incorporating material parameters obtained from the multiscale modeling approach we envisage. [1] S.S.P. Parkin, Z.G. Li, and D. J. Smith, Appl. Phys. Lett., 58, 2710-2712 (1991). [2] T. Charlton et al, Phys. Rev. B 63, 094404 (2001) [3] T. Charlton et al, Phys. Rev. B 59, 11897-11908 (1999) [4] C. Villagonzalo, A.K. Setty and B.R. Cooper, submitted to Phys. Rev. [5] J. Fassbender, R. Allenspach, and U. Durig. Surf. Sci., 383, L742-L748, (1997). [6] D.J. Larson et al, Appl. Phys. Lett., 73:1125-1127, (1998). [7] J. C. Slonczewski, Phys. Rev. B 39, 6995 (1989).

Two-dimensional distributed-phase-reference protocol for quantum key distribution

NASA Astrophysics Data System (ADS)

Bacco, Davide; Christensen, Jesper Bjerge; Castaneda, Mario A. Usuga; Ding, Yunhong; Forchhammer, Søren; Rottwitt, Karsten; Oxenløwe, Leif Katsuo

2016-12-01

Quantum key distribution (QKD) and quantum communication enable the secure exchange of information between remote parties. Currently, the distributed-phase-reference (DPR) protocols, which are based on weak coherent pulses, are among the most practical solutions for long-range QKD. During the last 10 years, long-distance fiber-based DPR systems have been successfully demonstrated, although fundamental obstacles such as intrinsic channel losses limit their performance. Here, we introduce the first two-dimensional DPR-QKD protocol in which information is encoded in the time and phase of weak coherent pulses. The ability of extracting two bits of information per detection event, enables a higher secret key rate in specific realistic network scenarios. Moreover, despite the use of more dimensions, the proposed protocol remains simple, practical, and fully integrable.

Two-dimensional distributed-phase-reference protocol for quantum key distribution.

PubMed

Bacco, Davide; Christensen, Jesper Bjerge; Castaneda, Mario A Usuga; Ding, Yunhong; Forchhammer, Søren; Rottwitt, Karsten; Oxenløwe, Leif Katsuo

2016-12-22

Quantum key distribution (QKD) and quantum communication enable the secure exchange of information between remote parties. Currently, the distributed-phase-reference (DPR) protocols, which are based on weak coherent pulses, are among the most practical solutions for long-range QKD. During the last 10 years, long-distance fiber-based DPR systems have been successfully demonstrated, although fundamental obstacles such as intrinsic channel losses limit their performance. Here, we introduce the first two-dimensional DPR-QKD protocol in which information is encoded in the time and phase of weak coherent pulses. The ability of extracting two bits of information per detection event, enables a higher secret key rate in specific realistic network scenarios. Moreover, despite the use of more dimensions, the proposed protocol remains simple, practical, and fully integrable.

Two-dimensional distributed-phase-reference protocol for quantum key distribution

PubMed Central

Bacco, Davide; Christensen, Jesper Bjerge; Castaneda, Mario A. Usuga; Ding, Yunhong; Forchhammer, Søren; Rottwitt, Karsten; Oxenløwe, Leif Katsuo

2016-01-01

Quantum key distribution (QKD) and quantum communication enable the secure exchange of information between remote parties. Currently, the distributed-phase-reference (DPR) protocols, which are based on weak coherent pulses, are among the most practical solutions for long-range QKD. During the last 10 years, long-distance fiber-based DPR systems have been successfully demonstrated, although fundamental obstacles such as intrinsic channel losses limit their performance. Here, we introduce the first two-dimensional DPR-QKD protocol in which information is encoded in the time and phase of weak coherent pulses. The ability of extracting two bits of information per detection event, enables a higher secret key rate in specific realistic network scenarios. Moreover, despite the use of more dimensions, the proposed protocol remains simple, practical, and fully integrable. PMID:28004821

Secure data sharing in public cloud

NASA Astrophysics Data System (ADS)

Venkataramana, Kanaparti; Naveen Kumar, R.; Tatekalva, Sandhya; Padmavathamma, M.

2012-04-01

Secure multi-party protocols have been proposed for entities (organizations or individuals) that don't fully trust each other to share sensitive information. Many types of entities need to collect, analyze, and disseminate data rapidly and accurately, without exposing sensitive information to unauthorized or untrusted parties. Solutions based on secure multiparty computation guarantee privacy and correctness, at an extra communication (too costly in communication to be practical) and computation cost. The high overhead motivates us to extend this SMC to cloud environment which provides large computation and communication capacity which makes SMC to be used between multiple clouds (i.e., it may between private or public or hybrid clouds).Cloud may encompass many high capacity servers which acts as a hosts which participate in computation (IaaS and PaaS) for final result, which is controlled by Cloud Trusted Authority (CTA) for secret sharing within the cloud. The communication between two clouds is controlled by High Level Trusted Authority (HLTA) which is one of the hosts in a cloud which provides MgaaS (Management as a Service). Due to high risk for security in clouds, HLTA generates and distributes public keys and private keys by using Carmichael-R-Prime- RSA algorithm for exchange of private data in SMC between itself and clouds. In cloud, CTA creates Group key for Secure communication between the hosts in cloud based on keys sent by HLTA for exchange of Intermediate values and shares for computation of final result. Since this scheme is extended to be used in clouds( due to high availability and scalability to increase computation power) it is possible to implement SMC practically for privacy preserving in data mining at low cost for the clients.

Who are the uninsured eligible for premium subsidies in the health insurance exchanges?

PubMed

Cunningham, Peter J

2010-12-01

A key provision of the national health reform law is the creation of state-based exchanges to provide more affordable insurance options for people, especially the uninsured. Despite premium subsidies for people with incomes up to 400 percent of the poverty level, or $88,200 for a family of four in 2010, and an individual requirement to enroll in coverage, no one knows who will enroll in the exchanges and who will not, at least initially. Almost 40 percent of uninsured people eligible to receive subsidies through the exchanges have chronic conditions or report fair or poor health, and another 28 percent report recent problems with access to care or paying medical bills, according to a new national study by the Center for Studying Health System Change (HSC). However, about one-third of uninsured people eligible for subsidies have had no recent problems with their health, access to medical care or paying medical bills. Enrolling these apparently healthy uninsured people is likely to be challenging but essential to avoiding adverse selection, or enrolling sicker-than-average people, in the exchanges. Otherwise, health insurance costs in the exchanges could be higher than expected. Contrary to popular perception, many of these healthy and low-cost uninsured people view themselves as risk-averse, which could motivate them to gain coverage in the absence of health or access problems. Also, most uninsured people believe they need health coverage, although fewer believe that health insurance is currently worth the cost, a situation that could change once premium subsidies are available in 2014.

Characteristics associated with regional health information organization viability.

PubMed

Adler-Milstein, Julia; Landefeld, John; Jha, Ashish K

2010-01-01

Regional Health Information Organizations (RHIOs) will likely play a key role in our nation's effort to catalyze health information exchange. Yet we know little about why some efforts succeed while others fail. We sought to identify factors associated with RHIO viability. Using data from a national survey of RHIOs that we conducted in mid-2008, we examined factors associated with becoming operational and factors associated with financial viability. We used multivariate logistic regression models to identify unique predictors. We classified RHIOs actively facilitating data exchange as operational and measured financial viability as the percent of operating costs covered by revenue from participants in data exchange (0-24%, 25-74%, 75-100%). Predictors included breadth of participants, breadth of data exchanged, whether the RHIO focused on a specific population, whether RHIO participants had a history of collaborating, and sources of revenue during the planning phase. Exchanging a narrow set of data and involving a broad group of stakeholders were independently associated with a higher likelihood of being operational. Involving hospitals and ambulatory physicians, and securing early funding from participants were associated with a higher likelihood of financial viability, while early grant funding seemed to diminish the likelihood. Finding ways to help RHIOs become operational and self-sustaining will bolster the current approach to nationwide health information exchange. Our work suggests that convening a broad coalition of stakeholders to focus on a narrow set of data is an important step in helping RHIOs become operational. Convincing stakeholders to financially commit early in the process may help RHIOs become self-sustaining.

RSA-Based Password-Authenticated Key Exchange, Revisited

NASA Astrophysics Data System (ADS)

Shin, Seonghan; Kobara, Kazukuni; Imai, Hideki

The RSA-based Password-Authenticated Key Exchange (PAKE) protocols have been proposed to realize both mutual authentication and generation of secure session keys where a client is sharing his/her password only with a server and the latter should generate its RSA public/private key pair (e, n), (d, n) every time due to the lack of PKI (Public-Key Infrastructures). One of the ways to avoid a special kind of off-line (so called e-residue) attacks in the RSA-based PAKE protocols is to deploy a challenge/response method by which a client verifies the relative primality of e and φ(n) interactively with a server. However, this kind of RSA-based PAKE protocols did not give any proof of the underlying challenge/response method and therefore could not specify the exact complexity of their protocols since there exists another security parameter, needed in the challenge/response method. In this paper, we first present an RSA-based PAKE (RSA-PAKE) protocol that can deploy two different challenge/response methods (denoted by Challenge/Response Method1 and Challenge/Response Method2). The main contributions of this work include: (1) Based on the number theory, we prove that the Challenge/Response Method1 and the Challenge/Response Method2 are secure against e-residue attacks for any odd prime e (2) With the security parameter for the on-line attacks, we show that the RSA-PAKE protocol is provably secure in the random oracle model where all of the off-line attacks are not more efficient than on-line dictionary attacks; and (3) By considering the Hamming weight of e and its complexity in the. RSA-PAKE protocol, we search for primes to be recommended for a practical use. We also compare the RSA-PAKE protocol with the previous ones mainly in terms of computation and communication complexities.

Study on the security of the authentication scheme with key recycling in QKD

NASA Astrophysics Data System (ADS)

Li, Qiong; Zhao, Qiang; Le, Dan; Niu, Xiamu

2016-09-01

In quantum key distribution (QKD), the information theoretically secure authentication is necessary to guarantee the integrity and authenticity of the exchanged information over the classical channel. In order to reduce the key consumption, the authentication scheme with key recycling (KR), in which a secret but fixed hash function is used for multiple messages while each tag is encrypted with a one-time pad (OTP), is preferred in QKD. Based on the assumption that the OTP key is perfect, the security of the authentication scheme has be proved. However, the OTP key of authentication in a practical QKD system is not perfect. How the imperfect OTP affects the security of authentication scheme with KR is analyzed thoroughly in this paper. In a practical QKD, the information of the OTP key resulting from QKD is partially leaked to the adversary. Although the information leakage is usually so little to be neglected, it will lead to the increasing degraded security of the authentication scheme as the system runs continuously. Both our theoretical analysis and simulation results demonstrate that the security level of authentication scheme with KR, mainly indicated by its substitution probability, degrades exponentially in the number of rounds and gradually diminishes to zero.

Nutrients in estuaries--an overview and the potential impacts of climate change.

PubMed

Statham, Peter J

2012-09-15

The fate and cycling of macronutrients introduced into estuaries depend upon a range of interlinked processes. Hydrodynamics and morphology in combination with freshwater inflow control the freshwater flushing time, and the timescale for biogeochemical processes to operate that include microbial activity, particle-dissolved phase interactions, and benthic exchanges. In some systems atmospheric inputs and exchanges with coastal waters can also be important. Climate change will affect nutrient inputs and behaviour through modifications to temperature, wind patterns, the hydrological cycle, and sea level rise. Resulting impacts include: 1) inundation of freshwater systems 2) changes in stratification, flushing times and phytoplankton productivity 3) increased coastal storm activity 4) changes in species and ecosystem function. A combination of continuing high inputs of nutrients through human activity and climate change is anticipated to lead to enhanced eutrophication in the future. The most obvious impacts of increasing global temperature will be in sub-arctic systems where permafrost zones will be reduced in combination with enhanced inputs from glacial systems. Improved process understanding in several key areas including cycling of organic N and P, benthic exchanges, resuspension, impact of bio-irrigation, particle interactions, submarine groundwater discharges, and rates and magnitude of bacterially-driven recycling processes, is needed. Development of high frequency in situ nutrient analysis systems will provide data to improve predictive models that need to incorporate a wider variety of key factors, although the complexity of estuarine systems makes such modelling a challenge. However, overall a more holistic approach is needed to effectively understand, predict and manage the impact of macronutrients on estuaries. Copyright © 2011 Elsevier B.V. All rights reserved.

Climate Change Information Dashboards for Water Resource Managers

NASA Astrophysics Data System (ADS)

Buja, Lawrence

2016-04-01

It is in the context of its application that one needs to determine if climate information is of high quality and ultimately useful. Therefore, it is important that the intersection between data providers and data consumers is structured in form of an iterative and collaborative exchange where science and application viewpoints can be brought together. A traditional "loading dock"-style hand-off of data fails to optimally inform decisions. It is now broadly recognized that a collaborative, open exchange is better suited to generate credible and salient products and knowledge that can be more confidently used in decisions. But in order for this exchange to be successful in practice, it needs to be sufficiently efficient to actually facilitate an exploratory process that is inherently iterative to determine the most informative products. It also requires a transparent approach that is easily understood and communicated. We will present prototypes of Climate Information Dashboards that collect on a single page to integrate a suite of key climate information for resource managers. The content of dashboards is based on standardized products that can be assembled to meet specific needs. They were co-designed with the water resource managers and are tailored to selected management and decision topics. The visualizations are tuned to quickly provide the basic information, yet below individual diagnostics are more detailed analyses that can be consulted. These dashboards offer a flexible way to connect decision-makers to climate model output. Conversely, such dashboards can also be applied to inform model development by providing insight into a suite of key characteristics of model performance that have been identified as critical by a sector.

The derivative discontinuity of the exchange-correlation functional.

PubMed

Mori-Sánchez, Paula; Cohen, Aron J

2014-07-28

The derivative discontinuity is a key concept in electronic structure theory in general and density functional theory in particular. The electronic energy of a quantum system exhibits derivative discontinuities with respect to different degrees of freedom that are a consequence of the integer nature of electrons. The classical understanding refers to the derivative discontinuity of the total energy as a function of the total number of electrons (N), but it can also manifest at constant N. Examples are shown in models including several hydrogen systems with varying numbers of electrons or nuclear charge (Z), as well as the 1-dimensional Hubbard model (1DHM). Two sides of the problem are investigated: first, the failure of currently used approximate exchange-correlation functionals in DFT and, second, the importance of the derivative discontinuity in the exact electronic structure of molecules, as revealed by full configuration interaction (FCI). Currently, all approximate functionals, including hybrids, miss the derivative discontinuity, leading to basic errors that can be seen in many ways: from the complete failure to give the total energy of H2 and H2(+), to the missing gap in Mott insulators such as stretched H2 and the thermodynamic limit of the 1DHM, or a qualitatively incorrect density in the HZ molecule with two electrons and incorrect electron transfer processes. Description of the exact particle behaviour of electrons is emphasised, which is key to many important physical processes in real systems, especially those involving electron transfer, and offers a challenge for the development of new exchange-correlation functionals.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reiter, R.; Kanter, H. J.; Sladkovic, R.

Studies of the stratospheric-tropospheric exchange were continued. Continuous data of the concentration of cosmogenic radionuclides /sup 7/Be, /sup 32/P, /sup 33/P, as well as of fallout and daily means of ozone concentrations, measured at 3000 m ASL are presented for the reporting period. Installation of two additional ozone measuring stations at 1800 and 740 m ASL provided the means for getting insight into the balance of the tropospheric ozone. First results of routine monitoring of the stratospheric aerosol with a high resolution lidar are shown. Accuracy of the method is discussed. Control of the stratospheric-tropospheric exchange by solar activity ismore » examined with the aid of the key day method using an 8-year measuring sequence. Relevant literature available on the subject is reviewed.« less

Speaker transfer in children's peer conversation: completing communication-aid-mediated contributions.

PubMed

Clarke, Michael; Bloch, Steven; Wilkinson, Ray

2013-03-01

Managing the exchange of speakers from one person to another effectively is a key issue for participants in everyday conversational interaction. Speakers use a range of resources to indicate, in advance, when their turn will come to an end, and listeners attend to such signals in order to know when they might legitimately speak. Using the principles and findings from conversation analysis, this paper examines features of speaker transfer in a conversation between a boy with cerebral palsy who has been provided with a voice-output communication aid (VOCA), and a peer without physical or communication difficulties. Specifically, the analysis focuses on turn exchange, where a VOCA-mediated contribution approach completion, and the child without communication needs is due to speak next.

Advancing the hydrogen safety knowledge base

DOE PAGES

Weiner, S. C.

2014-08-29

The International Energy Agency's Hydrogen Implementing Agreement (IEA HIA) was established in 1977 to pursue collaborative hydrogen research and development and information exchange among its member countries. Information and knowledge dissemination is a key aspect of the work within IEA HIA tasks, and case studies, technical reports and presentations/publications often result from the collaborative efforts. The work conducted in hydrogen safety under Task 31 and its predecessor, Task 19, can positively impact the objectives of national programs even in cases for which a specific task report is not published. As a result, the interactions within Task 31 illustrate how technologymore » information and knowledge exchange among participating hydrogen safety experts serve the objectives intended by the IEA HIA.« less

Bit-level quantum color image encryption scheme with quantum cross-exchange operation and hyper-chaotic system

NASA Astrophysics Data System (ADS)

Zhou, Nanrun; Chen, Weiwei; Yan, Xinyu; Wang, Yunqian

2018-06-01

In order to obtain higher encryption efficiency, a bit-level quantum color image encryption scheme by exploiting quantum cross-exchange operation and a 5D hyper-chaotic system is designed. Additionally, to enhance the scrambling effect, the quantum channel swapping operation is employed to swap the gray values of corresponding pixels. The proposed color image encryption algorithm has larger key space and higher security since the 5D hyper-chaotic system has more complex dynamic behavior, better randomness and unpredictability than those based on low-dimensional hyper-chaotic systems. Simulations and theoretical analyses demonstrate that the presented bit-level quantum color image encryption scheme outperforms its classical counterparts in efficiency and security.

Plasma Discharge Process in a Pulsed Diaphragm Discharge System

NASA Astrophysics Data System (ADS)

Duan, Jianjin; Hu, Jue; Zhang, Chao; Wen, Yuanbin; Meng, Yuedong; Zhang, Chengxu

2014-12-01

As one of the most important steps in wastewater treatment, limited study on plasma discharge process is a key challenge in the development of plasma applications. In this study, we focus on the plasma discharge process of a pulsed diaphragm discharge system. According to the analysis, the pulsed diaphragm discharge proceeds in seven stages: (1) Joule heating and heat exchange stage; (2) nucleated site formation; (3) plasma generation (initiation of the breakdown stage); (4) avalanche growth and plasma expansion; (5) plasma contraction; (6) termination of the plasma discharge; and (7) heat exchange stage. From this analysis, a critical voltage criterion for breakdown is obtained. We anticipate this finding will provide guidance for a better application of plasma discharges, especially diaphragm plasma discharges.

Exchange stiffness in thin film Co alloys

NASA Astrophysics Data System (ADS)

Eyrich, C.; Huttema, W.; Arora, M.; Montoya, E.; Rashidi, F.; Burrowes, C.; Kardasz, B.; Girt, E.; Heinrich, B.; Mryasov, O. N.; From, M.; Karis, O.

2012-04-01

The exchange stiffness (Aex) is one of the key parameters controlling magnetization reversal in magnetic materials. We used a method based on the spin spiral formation in two ferromagnetic films antiferromagnetically coupled across a non-magnetic spacer layer and Brillouin scattering to measure Aex for a series of Co1-δXδ (X = Cr, Ni, Ru, Pd, Pt) thin film alloys. The results show that Aex of Co alloys does not necessarily scale with Ms; Aex approximately decreases at the rate of 1.1%, 1.5%, 2.1%, 3.5%, and 5.6%, while Ms decreases at the rate of 1.1%, 0.5%, 1.1%, 3.7%, and 2.5% per addition of 1 at % of Pt, Ni, Pd, Cr, and Ru, respectively.

The Effect of Shared Information on Pilot/Controller and Controller/Controller Interactions

NASA Technical Reports Server (NTRS)

Hansman, R. John; Davison, Hayley J.

2000-01-01

The increased ability to exchange information between Pilots, Controllers, Dispatchers, and other agents is a key component of advanced Air Traffic Management. The importance of shared information as well as current and evolving practices in information sharing are presented for a variety of interactions including: Controller/Pilot interactions, Pilot/Airline interactions, Controller/Controller interactions, and Airline/ATM interactions.

The Role of Trust in Creating Value and Student Loyalty in Relational Exchanges between Higher Education Institutions and Their Students

ERIC Educational Resources Information Center

Carvalho, Sergio W.; de Oliveira Mota, Marcio

2010-01-01

The globalization of educational services and the increasing competition coming from the private sector have forced higher education institutions to market their programs more aggressively and to look at student loyalty as the key for future success. Student loyalty to higher education institutions represents not only a more stable financial basis…

Soil CO2 dynamics and fluxes as affected by tree harvest in an experimental sand ecosystem.

Treesearch

C.K. Keller; T.M. White; R. O' Brien; J.L. Smith

2006-01-01

Soil CO2 production is a key process in ecosystem C exchange, and global change predictions require understanding of how ecosystem disturbance affects this process. We monitored CO2 levels in soil gas and as bicarbonate in drainage from an experimental red pine ecosystem, for 1 year before and 3 years after its aboveground...

United Nations Office on Drugs and Crime International Network of Drug Dependence Treatment and Rehabilitation Resource Centres: Treatnet

ERIC Educational Resources Information Center

Tomas-Rossello, Juana; Rawson, Richard A.; Zarza, Maria J.; Bellows, Anne; Busse, Anja; Saenz, Elizabeth; Freese, Thomas; Shawkey, Mansour; Carise, Deni; Ali, Robert; Ling, Walter

2010-01-01

Key to the dissemination of evidence-based addiction treatments is the exchange of experiences and mutual support among treatment practitioners, as well as the availability of accurate addiction training materials and effective trainers. To address the shortage of such resources, the United Nations Office on Drugs and Crime (UNODC) created…

Using Participatory Analysis for Community Action: Idea Book. Information Collection and Exchange Publication No. M0086

ERIC Educational Resources Information Center

Peace Corps, 2010

2010-01-01

This idea book addresses key concepts in two earlier Peace Corps' publications, "Participatory Analysis for Community Action (PACA) Manual" [ICE No. M0053], and the "Gender and Development Training Manual" [ICE No. M0054]. These previous resources were large training manuals that introduced PACA to staff and Volunteers in the context of the Peace…

Task Analyses for Difficult-to-Assess Collective Tasks

DTIC Science & Technology

2014-02-01

FOR THE KLE MISSION Review and rehearse social nuances, customs, and etiquette of the host nation, e.g., gift exchange expectations. Practice... etiquette to foster rapport with the leader and demonstrate cultural awareness. Negotiate with the key leader in a manner that demonstrates...requirements for police applicants by establishing minimum entry requirements, physical fitness tests, literacy tests, and medical screening protocols

A provably-secure ECC-based authentication scheme for wireless sensor networks.

PubMed

Nam, Junghyun; Kim, Moonseong; Paik, Juryon; Lee, Youngsook; Won, Dongho

2014-11-06

A smart-card-based user authentication scheme for wireless sensor networks (in short, a SUA-WSN scheme) is designed to restrict access to the sensor data only to users who are in possession of both a smart card and the corresponding password. While a significant number of SUA-WSN schemes have been suggested in recent years, their intended security properties lack formal definitions and proofs in a widely-accepted model. One consequence is that SUA-WSN schemes insecure against various attacks have proliferated. In this paper, we devise a security model for the analysis of SUA-WSN schemes by extending the widely-accepted model of Bellare, Pointcheval and Rogaway (2000). Our model provides formal definitions of authenticated key exchange and user anonymity while capturing side-channel attacks, as well as other common attacks. We also propose a new SUA-WSN scheme based on elliptic curve cryptography (ECC), and prove its security properties in our extended model. To the best of our knowledge, our proposed scheme is the first SUA-WSN scheme that provably achieves both authenticated key exchange and user anonymity. Our scheme is also computationally competitive with other ECC-based (non-provably secure) schemes.

A Provably-Secure ECC-Based Authentication Scheme for Wireless Sensor Networks

PubMed Central

Nam, Junghyun; Kim, Moonseong; Paik, Juryon; Lee, Youngsook; Won, Dongho

2014-01-01

A smart-card-based user authentication scheme for wireless sensor networks (in short, a SUA-WSN scheme) is designed to restrict access to the sensor data only to users who are in possession of both a smart card and the corresponding password. While a significant number of SUA-WSN schemes have been suggested in recent years, their intended security properties lack formal definitions and proofs in a widely-accepted model. One consequence is that SUA-WSN schemes insecure against various attacks have proliferated. In this paper, we devise a security model for the analysis of SUA-WSN schemes by extending the widely-accepted model of Bellare, Pointcheval and Rogaway (2000). Our model provides formal definitions of authenticated key exchange and user anonymity while capturing side-channel attacks, as well as other common attacks. We also propose a new SUA-WSN scheme based on elliptic curve cryptography (ECC), and prove its security properties in our extended model. To the best of our knowledge, our proposed scheme is the first SUA-WSN scheme that provably achieves both authenticated key exchange and user anonymity. Our scheme is also computationally competitive with other ECC-based (non-provably secure) schemes. PMID:25384009

Platinum group metal-free electrocatalysts: Effects of synthesis on structure and performance in proton-exchange membrane fuel cell cathodes

NASA Astrophysics Data System (ADS)

Workman, Michael J.; Dzara, Michael; Ngo, Chilan; Pylypenko, Svitlana; Serov, Alexey; McKinney, Sam; Gordon, Jonathan; Atanassov, Plamen; Artyushkova, Kateryna

2017-04-01

Development of platinum group metal free catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs) requires understanding of the interactions between surface chemistry and performance, both of which are strongly dependent on synthesis conditions. To elucidate these complex relationships, a set of Fe-N-C catalysts derived from the same set of precursor materials is fabricated by varying several key synthetic parameters under controlled conditions. The results of physicochemical characterization are presented and compared with the results of rotating disk electrode (RDE) analysis and fuel cell testing. We find that electrochemical performance is strongly correlated with three key properties related to catalyst composition: concentrations of 1) atomically dispersed Fe species, 2) species in which N is bound to Fe, and 3) surface oxides. Not only are these factors related to performance, these types of chemical species are shown to correlate with each other. This study provides evidence supporting the role of iron coordinated with nitrogen as an active species for the ORR, and offers synthetic pathways to increase the density of atomically dispersed iron species and surface oxides for optimum performance.

Endothelial glycocalyx: permeability barrier and mechanosensor.

PubMed

Curry, F E; Adamson, R H

2012-04-01

Endothelial cells are covered with a polysaccharide rich layer more than 400 nm thick, mechanical properties of which limit access of circulating plasma components to endothelial cell membranes. The barrier properties of this endothelial surface layer are deduced from the rate of tracer penetration into the layer and the mechanics of red and white cell movement through capillary microvessels. This review compares the mechanosensor and permeability properties of an inner layer (100-150 nm, close to the endothelial membrane) characterized as a quasi-periodic structure which accounts for key aspects of transvascular exchange and vascular permeability with those of the whole endothelial surface layers. We conclude that many of the barrier properties of the whole surface layer are not representative of the primary fiber matrix forming the molecular filter determining transvascular exchange. The differences between the properties of the whole layer and the inner glycocalyx structures likely reflect dynamic aspects of the endothelial surface layer including tracer binding to specific components, synthesis and degradation of key components, activation of signaling pathways in the endothelial cells when components of the surface layer are lost or degraded, and the spatial distribution of adhesion proteins in microdomains of the endothelial cell membrane.

Sensitivity and uncertainty analysis for Abreu & Johnson numerical vapor intrusion model.

PubMed

Ma, Jie; Yan, Guangxu; Li, Haiyan; Guo, Shaohui

2016-03-05

This study conducted one-at-a-time (OAT) sensitivity and uncertainty analysis for a numerical vapor intrusion model for nine input parameters, including soil porosity, soil moisture, soil air permeability, aerobic biodegradation rate, building depressurization, crack width, floor thickness, building volume, and indoor air exchange rate. Simulations were performed for three soil types (clay, silt, and sand), two source depths (3 and 8m), and two source concentrations (1 and 400 g/m(3)). Model sensitivity and uncertainty for shallow and high-concentration vapor sources (3m and 400 g/m(3)) are much smaller than for deep and low-concentration sources (8m and 1g/m(3)). For high-concentration sources, soil air permeability, indoor air exchange rate, and building depressurization (for high permeable soil like sand) are key contributors to model output uncertainty. For low-concentration sources, soil porosity, soil moisture, aerobic biodegradation rate and soil gas permeability are key contributors to model output uncertainty. Another important finding is that impacts of aerobic biodegradation on vapor intrusion potential of petroleum hydrocarbons are negligible when vapor source concentration is high, because of insufficient oxygen supply that limits aerobic biodegradation activities. Copyright © 2015 Elsevier B.V. All rights reserved.

A Privacy-Preserving Platform for User-Centric Quantitative Benchmarking

NASA Astrophysics Data System (ADS)

Herrmann, Dominik; Scheuer, Florian; Feustel, Philipp; Nowey, Thomas; Federrath, Hannes

We propose a centralised platform for quantitative benchmarking of key performance indicators (KPI) among mutually distrustful organisations. Our platform offers users the opportunity to request an ad-hoc benchmarking for a specific KPI within a peer group of their choice. Architecture and protocol are designed to provide anonymity to its users and to hide the sensitive KPI values from other clients and the central server. To this end, we integrate user-centric peer group formation, exchangeable secure multi-party computation protocols, short-lived ephemeral key pairs as pseudonyms, and attribute certificates. We show by empirical evaluation of a prototype that the performance is acceptable for reasonably sized peer groups.

Quantum key distribution with 1.25 Gbps clock synchronization.

PubMed

Bienfang, J; Gross, A; Mink, A; Hershman, B; Nakassis, A; Tang, X; Lu, R; Su, D; Clark, Charles; Williams, Carl; Hagley, E; Wen, Jesse

2004-05-03

We have demonstrated the exchange of sifted quantum cryptographic key over a 730 meter free-space link at rates of up to 1.0 Mbps, two orders of magnitude faster than previously reported results. A classical channel at 1550 nm operates in parallel with a quantum channel at 845 nm. Clock recovery techniques on the classical channel at 1.25 Gbps enable quantum transmission at up to the clock rate. System performance is currently limited by the timing resolution of our silicon avalanche photodiode detectors. With improved detector resolution, our technique will yield another order of magnitude increase in performance, with existing technology.

Situational and dispositional influences on nurses' workplace well-being: the role of empowering unit leadership.

PubMed

Spence Laschinger, Heather K; Finegan, Joan; Wilk, Piotr

2011-01-01

Unit-level leadership and structural empowerment play key roles in creating healthy work environments, yet few researchers have examined these contextual effects on nurses' well-being. The aim of this study was to test a multilevel model of structural empowerment examining the effect of nursing unit leadership quality and structural empowerment on nurses' experiences of burnout and job satisfaction and to examine the effect of a personal dispositional variable, core self-evaluation, on these nurse experiences. Nurses (n = 3,156) from 217 hospital units returned surveys that included measures of leader-member exchange, structural empowerment, burnout, core self-evaluation, and job satisfaction. Multilevel structural equation modeling was used to test the model. Nurses' shared perceptions of leader-member exchange quality on their units positively influenced their shared perceptions of unit structural empowerment (Level 2), which resulted in significantly higher levels of individual nurse job satisfaction (Level 1). Unit-level leader-member exchange quality also directly influenced individual nurse job satisfaction. Unit leader-member exchange quality and structural empowerment influenced emotional exhaustion and cynicism differentially. Higher unit-level leader-member exchange quality was associated with lower cynicism; higher unit-level structural empowerment was associated with lower emotional exhaustion. At Level 1, higher core self-evaluation was associated with lower levels of both emotional exhaustion and cynicism, both of which were associated with lower job satisfaction. This study provides a theoretical understanding of how unit leadership affects both unit- and individual-level outcomes.

Asymmetry of inverted-topology repeats in the AE1 anion exchanger suggests an elevator-like mechanism

PubMed Central

Faraldo-Gómez, José D.

2017-01-01

The membrane transporter anion exchanger 1 (AE1), or band 3, is a key component in the processes of carbon-dioxide transport in the blood and urinary acidification in the renal collecting duct. In both erythrocytes and the basolateral membrane of the collecting-duct α-intercalated cells, the role of AE1 is to catalyze a one-for-one exchange of chloride for bicarbonate. After decades of biochemical and functional studies, the structure of the transmembrane region of AE1, which catalyzes the anion-exchange reaction, has finally been determined. Each protomer of the AE1 dimer comprises two repeats with inverted transmembrane topologies, but the structures of these repeats differ. This asymmetry causes the putative substrate-binding site to be exposed only to the extracellular space, consistent with the expectation that anion exchange occurs via an alternating-access mechanism. Here, we hypothesize that the unknown, inward-facing conformation results from inversion of this asymmetry, and we propose a model of this state constructed using repeat-swap homology modeling. By comparing this inward-facing model with the outward-facing experimental structure, we predict that the mechanism of AE1 involves an elevator-like motion of the substrate-binding domain relative to the nearly stationary dimerization domain and to the membrane plane. This hypothesis is in qualitative agreement with a wide range of biochemical and functional data, which we review in detail, and suggests new avenues of experimentation. PMID:29167180

Application of linear pH gradients for the modeling of ion exchange chromatography: Separation of monoclonal antibody monomer from aggregates.

PubMed

Kluters, Simon; Wittkopp, Felix; Jöhnck, Matthias; Frech, Christian

2016-02-01

The mobile phase pH is a key parameter of every ion exchange chromatography process. However, mechanistic insights into the pH influence on the ion exchange chromatography equilibrium are rare. This work describes a mechanistic model capturing salt and pH influence in ion exchange chromatography. The pH dependence of the characteristic protein charge and the equilibrium constant is introduced to the steric mass action model based on a protein net charge model considering the number of amino acids interacting with the stationary phase. This allows the description of the adsorption equilibrium of the chromatographed proteins as a function of pH. The model parameters were determined for a monoclonal antibody monomer, dimer, and a higher aggregated species based on a manageable set of pH gradient experiments. Without further modification of the model parameters the transfer to salt gradient elution at fixed pH is demonstrated. A lumped rate model was used to predict the separation of the monoclonal antibody monomer/aggregate mixture in pH gradient elution and for a pH step elution procedure-also at increased protein loadings up to 48 g/L packed resin. The presented model combines both salt and pH influence and may be useful for the development and deeper understanding of an ion exchange chromatography separation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Probing the Gaseous Structure of a β-Hairpin Peptide with H/D Exchange and Electron Capture Dissociation

NASA Astrophysics Data System (ADS)

Straus, Rita N.; Jockusch, Rebecca A.

2017-02-01

An improved understanding of the extent to which native protein structure is retained upon transfer to the gas phase promises to enhance biological mass spectrometry, potentially streamlining workflows and providing fundamental insights into hydration effects. Here, we investigate the gaseous conformation of a model β-hairpin peptide using gas-phase hydrogen-deuterium (H/D) exchange with subsequent electron capture dissociation (ECD). Global gas-phase H/D exchange levels, and residue-specific exchange levels derived from ECD data, are compared among the wild type 16-residue peptide GB1p and several variants. High protection from H/D exchange observed for GB1p, but not for a truncated version, is consistent with the retention of secondary structure of GB1p in the gas phase or its refolding into some other compact structure. Four alanine mutants that destabilize the hairpin in solution show levels of protection similar to that of GB1p, suggesting collapse or (re)folding of these peptides upon transfer to the gas phase. These results offer a starting point from which to understand how a key secondary structural element, the β-hairpin, is affected by transfer to the gas phase. This work also demonstrates the utility of a much-needed addition to the tool set that is currently available for the investigation of the gaseous conformation of biomolecules, which can be employed in the future to better characterize gaseous proteins and protein complexes.