Strength of forelimb lateralization predicts motor errors in an insect

Lateralized behaviours are widespread in both vertebrates and invertebrates, suggesting that lateralization is advantageous. Yet evidence demonstrating proximate or ultimate advantages remains scarce, particularly in invertebrates or in species with individual-level lateralization. Desert locusts (Schistocerca gregaria) are biased in the forelimb they use to perform targeted reaching across a gap. The forelimb and strength of this bias differed among individuals, indicative of individual-level lateralization. Here we show that strongly biased locusts perform better during gap-crossing, making fewer errors with their preferred forelimb. The number of targeting errors locusts make negatively correlates with the strength of forelimb lateralization. This provides evidence that stronger lateralization confers an advantage in terms of improved motor control in an invertebrate with individual-level lateralization

Practical issues in quantum-key-distribution postprocessing

Quantum key distribution (QKD) is a secure key generation method between two distant parties by wisely exploiting properties of quantum mechanics. In QKD, experimental measurement outcomes on quantum states are transformed by the two parties to a secret key. This transformation is composed of many logical steps (as guided by security proofs), which together will ultimately determine the length of the final secret key and its security. We detail the procedure for performing such classical postprocessing taking into account practical concerns (including the finite-size effect and authentication and encryption for classical communications). This procedure is directly applicable to realistic QKD experiments and thus serves as a recipe that specifies what postprocessing operations are needed and what the security level is for certain lengths of the keys. Our result is applicable to the BB84 protocol with a single or entangled photon source. © 2010 The American Physical Society.published_or_final_versio

Universal squash model for optical communications using linear optics and threshold detectors

Transmission of photons through open-air or optical fibers is an important primitive in quantum-information processing. Theoretical descriptions of this process often consider single photons as information carriers and thus fail to accurately describe experimental implementations where any number of photons may enter a detector. It has been a great challenge to bridge this big gap between theory and experiments. One powerful method for achieving this goal is by conceptually squashing the received multiphoton states to single-photon states. However, until now, only a few protocols admit a squash model; furthermore, a recently proven no-go theorem appears to rule out the existence of a universal squash model. Here we show that a necessary condition presumed by all existing squash models is in fact too stringent. By relaxing this condition, we find that, rather surprisingly, a universal squash model actually exists for many protocols, including quantum key distribution, quantum state tomography, Bell's inequality testing, and entanglement verification. © 2011 American Physical Society.published_or_final_versio

Unconditional security proof of a deterministic quantum key distribution with a two-way quantum channel

In a deterministic quantum key distribution (DQKD) protocol with a two-way quantum channel, Bob sends a qubit to Alice who then encodes a key bit onto the qubit and sends it back to Bob. After measuring the returned qubit, Bob can obtain Alice's key bit immediately, without basis reconciliation. Since an eavesdropper may attack the qubits traveling on either the Bob-Alice channel or the Alice-Bob channel, the security analysis of DQKD protocol with a two-way quantum channel is complicated and its unconditional security has been controversial. This paper presents a security proof of a single-photon four-state DQKD protocol against general attacks. © 2011 American Physical Society.published_or_final_versio

Solution to Time-energy Costs of Quantum Channels

We derive a formula for the time-energy costs of general quantum channels proposed in [Phys. Rev. A 88, 012307 (2013)]. This formula allows us to numerically find the time-energy cost of any quantum channel using positive semidefinite programming. We also derive a lower bound to the time-energy cost for any channels and the exact the time-energy cost for a class of channels which includes the qudit depolarizing channels and projector channels as special cases.postprin

Universally composable and customizable post-processing for practical quantum key distribution

In quantum key distribution (QKD), a secret key is generated between two distant parties by transmitting quantum states. Experimental measurements on the quantum states are then transformed to a secret key by classical post-processing. Here, we propose a construction framework in which QKD classical post-processing can be custom made. Though seemingly obvious, the concept of concatenating classical blocks to form a whole procedure does not automatically apply to the formation of a quantum cryptographic procedure since the security of the entire QKD procedure rests on the laws of quantum mechanics and classical blocks are originally designed and characterized without regard to any properties of these laws. Nevertheless, we justify such concept of concatenating classical blocks in constructing QKD classical post-processing procedures, along with a relation to the universal-composability-security parameter. Consequently, effects arising from an actual QKD experiment, such as those due to the finiteness of the number of signals used, can be dealt with by employing suitable post-processing blocks. Lastly, we use our proposed customizable framework to build a comprehensive generic recipe for classical post-processing that one can follow to derive a secret key from the measurement outcomes in an actual experiment. © 2010 Elsevier Ltd. All rights reserved.postprin

Charcot: Buddhist Leanings?

Jean-Martin Charcot, considered the father of modern neurology, had a complex personality featuring well-defined characteristics of introversion, competitiveness, irony, and skepticism. While biographers have described him as Republican, anticlerical, and agnostic, the literature also presents evidence that he came to admire Buddhism toward the end of his life; Charcot’s involvement with numerous patients suffering from incurable and insidious neurological diseases may have contributed to this change in attitude

Pharmacy-based interdisciplinary intervention for patients with chronic heart failure: results of the PHARM-CHF randomized controlled trial.

AIMS:Medication non-adherence is frequent and is associated with high morbidity and mortality in patients with chronic heart failure (CHF). We investigated whether an interdisciplinary intervention improves adherence in elderly CHF patients. METHODS AND RESULTS:The study population (mean age 74 years, 62% male, mean left ventricular ejection fraction 47%, 52% in New York Heart Association class III) consisted of 110 patients randomized into the pharmacy care and 127 into the usual care group. The median follow-up was 2.0 years (interquartile range 1.2-2.7). The pharmacy care group received a medication review followed by regular dose dispensing and counselling. Control patients received usual care. The primary endpoint was medication adherence as proportion of days covered (PDC) within 365 days for three classes of heart failure medications (beta-blockers, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, and mineralocorticoid receptor antagonists). The main secondary outcome was the proportion of adherent patients (PDC ≥ 80%). The primary safety endpoint was days lost due to unplanned cardiovascular hospitalizations (blindly adjudicated) or death. Pharmacy care compared with usual care resulted in an absolute increase in mean adherence to three heart failure medications for 365 days [adjusted difference 5.7%, 95% confidence interval (CI) 1.6-9.8, P = 0.007]. The proportion of patients classified as adherent increased (odds ratio 2.9, 95% CI 1.4-5.9, P = 0.005). Pharmacy care improved quality of life after 2 years (adjusted difference in Minnesota Living with Heart Failure Questionnaire scores -7.8 points (-14.5 to -1.1; P = 0.02), compared to usual care. Pharmacy care did not affect the safety endpoints of hospitalizations or deaths. CONCLUSION:Pharmacy care safely improved adherence to heart failure medications and quality of life