41,168 research outputs found
Mitochondrial heteroplasmy in an avian hybrid form (Passer italiae: Aves, Passeriformes)
Mitochondrial heteroplasmy is the result from biparental transmission of mitochondrial DNA (mtDNA) to the offspring. In such rare cases, maternal and paternal mtDNA is present in the same individual. Though recent studies suggested that mtDNA heteroplasmy might be more common than previously anticipated, that phenomenon is still poorly documented and was mostly detected in case studies on hybrid populations. The Italian sparrow, Passer italiae is a homoploid hybrid form that occurs all across the Italian Peninsula mostly under strict absence of either of its parent species, the house sparrow (P. domesticus) and the Spanish sparrow (P. hispaniolensis). In this study, we document a new case of mitochondrial heteroplasmy from two island populations of P. italiae (Ustica and Lipari). Our analysis was based on the mitochondrial NADH dehydrogenase subunit 2 (ND2) that allows for a clear distinction between mitochondrial lineages of the two parental species. We amplified and sequenced the mitochondrial ND2 gene with specifically designed primer combinations for each of the two parental species. In two of our study populations, a single individual carried two different ND2 haplotypes from each of the two parental lineages. These findings contribute to current knowledge on the still poorly documented phenomenon of paternal leakage in vertebrates
Beating the PNS attack in practical quantum cryptography
In practical quantum key distribution, weak coherent state is often used and
the channel transmittance can be very small therefore the protocol could be
totally insecure under the photon-number-splitting attack. We propose an
efficient method to verify the upper bound of the fraction of counts caused by
multi-photon pluses transmitted from Alice to Bob, given whatever type of Eve's
action. The protocol simply uses two coherent states for the signal pulses and
vacuum for decoy pulse. Our verified upper bound is sufficiently tight for QKD
with very lossy channel, in both asymptotic case and non-asymptotic case. The
coherent states with mean photon number from 0.2 to 0.5 can be used in
practical quantum cryptography. We show that so far our protocol is the
decoy-state protocol that really works for currently existing set-ups.Comment: So far this is the unique decoy-state protocol which really works
efficiently in practice. Prior art results are commented in both main context
and the Appendi
Insecurity of position-based quantum cryptography protocols against entanglement attacks
Recently, position-based quantum cryptography has been claimed to be
unconditionally secure. In contrary, here we show that the existing proposals
for position-based quantum cryptography are, in fact, insecure if entanglement
is shared among two adversaries. Specifically, we demonstrate how the
adversaries can incorporate ideas of quantum teleportation and quantum secret
sharing to compromise the security with certainty. The common flaw to all
current protocols is that the Pauli operators always map a codeword to a
codeword (up to an irrelevant overall phase). We propose a modified scheme
lacking this property in which the same cheating strategy used to undermine the
previous protocols can succeed with a rate at most 85%. We conjecture that the
modified protocol is unconditionally secure and prove this to be true when the
shared quantum resource between the adversaries is a two- or three- level
system
Secure and efficient decoy-state quantum key distribution with inexact pulse intensities
We present a general theorem for the efficient verification of the lower
bound of single-photon transmittance. We show how to do decoy-state quantum key
distribution efficiently with large random errors in the intensity control. In
our protocol, the linear terms of fluctuation disappear and only the quadratic
terms take effect. We then show the unconditional security of decoy-state
method with whatever error pattern in intensities of decoy pulses and signal
pulses provided that the intensity of each decoy pulse is less than and
the intensity of each signal pulse is larger than
Early childhood during Indonesia's wildfires: health outcomes and long-run schooling achievements
This paper empirically investigates the relationship between early childhood health conditions and subsequent educational achievements in a large sample of Indonesian children. I use a long-term panel data set and apply a maternal fixed effect plus an instrumental variables estimator in order to control for possible correlation between some of the components of the error term and the main independent variable, which is likely to cause a bias in the estimates. Differences in health status between siblings are identified by using exposure in early years of life to drought, wildfires, and associated smoke/haze, which seriously affected some parts of Indonesia in late 1997. The estimation results show that health capital (measured by height-for-age z-scores during childhood) significantly and positively affects the number of completed grades of schooling and the readiness to enter school. Nevertheless, I do not find significant evidence of an effect on cognitive test scores
Magic mirror on the wall: Selfie-related behavior as mediator of the relationship between narcissism and problematic smartphone use
Objective: Recent research has suggested that problematic smartphone use is associated with several psychological factors and that mobile apps and smartphone-related behavior (i.e. selfi e behavior) may encourage the development of problematic smartphone use. However, little is known about how the interplay between dysfunctional personality characteristics and selfi e-related behavior can infl uence problematic smartphone use. The aim of this study was to examine the relationship between narcissism and problematic smartphone use, as well as the mediating role of selfi e-related behavior in this relationship among young men and women. Method: In the current study, a total of 627 undergraduate students (283 males and 344 females) completed a cross-sectional survey. A structural equation model was tested separately for males and females in order to evaluate the associations between narcissism, selfi e-related behavior and problematic smartphone use. Results: The results showed that greater narcissism was related to increased selfi e-related behavior, which in turn were positively associated with problematic smartphone use both for males and females. However, selfi e-related behavior mediated the relationship between narcissism and problematic smartphone use only for females. Conclusions: The study provides fresh insight into our understanding of the psychological mechanisms underlying problematic smartphone use, which may inform prevention and treatment interventions
Coin Tossing is Strictly Weaker Than Bit Commitment
We define cryptographic assumptions applicable to two mistrustful parties who
each control two or more separate secure sites between which special relativity
guarantees a time lapse in communication. We show that, under these
assumptions, unconditionally secure coin tossing can be carried out by
exchanges of classical information. We show also, following Mayers, Lo and
Chau, that unconditionally secure bit commitment cannot be carried out by
finitely many exchanges of classical or quantum information. Finally we show
that, under standard cryptographic assumptions, coin tossing is strictly weaker
than bit commitment. That is, no secure classical or quantum bit commitment
protocol can be built from a finite number of invocations of a secure coin
tossing black box together with finitely many additional information exchanges.Comment: Final version; to appear in Phys. Rev. Let
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