125 research outputs found
Device-independent verifiable blind quantum computation
As progress on experimental quantum processors continues to advance, the problem of verifying the correct operation of such devices is becoming a pressing concern. The recent discovery of protocols for verifying computation performed by entangled but non-communicating quantum processors holds the promise of certifying the correctness of arbitrary quantum computations in a fully device-independent manner. Unfortunately, all known schemes have prohibitive overhead, with resources scaling as extremely high degree polynomials in the number of gates constituting the computation. Here we present a novel approach based on a combination of verified blind quantum computation and Bell state self-testing. This approach has dramatically reduced overhead, with resources scaling as only O(m4lnm) in the number of gates
Phase diffusion and the small-noise approximation in linear amplifiers: Limitations and beyond
The phase of an optical field inside a linear amplifier is widely known to
diffuse with a diffusion coefficient that is inversely proportional to the
photon number. The same process occurs in lasers which limits its intrinsic
linewidth and makes the phase uncertainty difficult to calculate. The most
commonly used simplification is to assume a narrow photon-number distribution
for the optical field (which we call the small-noise approximation). For
coherent light, this condition is determined by the average photon number. The
small-noise approximation relies on (i) the input to have a good
signal-to-noise ratio, and (ii) that such a signal-to-noise ratio can be
maintained throughout the amplification process. Here we ask: For a coherent
input, how many photons must be present in the input to a quantum linear
amplifier for the phase noise at the output to be amenable to a small-noise
analysis? We address these questions by showing how the phase uncertainty can
be obtained without recourse to the small-noise approximation. It is shown that
for an ideal linear amplifier (i.e. an amplifier most favourable to the
small-noise approximation), the small-noise approximation breaks down with only
a few photons on average. Interestingly, when the input strength is increased
to tens of photons, the small-noise approximation can be seen to perform much
better and the process of phase diffusion permits a small-noise analysis. This
demarcates the limit of the small-noise assumption in linear amplifiers as such
an assumption is less true for a nonideal amplifier
Invasive potential of Borrelia burgdorferi sensu stricto ospC type L strains increases the possible disease risk to humans in the regions of their distribution
Preliminary Evaluation of Tick Protein Extracts and Recombinant Ferritin 2 as Anti-tick Vaccines Targeting Ixodes ricinus in Cattle
Anti-tick vaccines have the potential to be an environmentally friendly and cost-effective option for tick control. In vaccine development, the identification of efficacious antigens forms the major bottleneck. In this study, the efficacy of immunization with recombinant ferritin 2 and native tick protein extracts (TPEs) against Ixodes ricinus infestations in calves was assessed in two immunization experiments. In the first experiment, each calf (n = 3) was immunized twice with recombinant ferritin 2 from I. ricinus (IrFER2), TPE consisting of soluble proteins from the internal organs of partially fed I. ricinus females, or adjuvant, respectively. In the second experiment, each calf (n = 4) was immunized with protein extracts from the midgut (ME) of partially fed females, the salivary glands (SGE) of partially fed females, a combination of ME and SGE, or adjuvant, respectively. Two weeks after the booster immunization, calves were challenged with 100 females and 200 nymphs. Blood was collected from the calves before the first and after the second immunization and fed to I. ricinus females and nymphs using an in vitro artificial tick feeding system. The two calves vaccinated with whole TPE and midgut extract (ME) showed hyperemia on tick bite sites 2 days post tick infestation and exudative blisters were observed in the ME-vaccinated animal, signs that were suggestive of a delayed type hypersensitivity (DTH) reaction. Significantly fewer ticks successfully fed on the three animals vaccinated with TPE, SGE, or ME. Adults fed on the TPE and ME vaccinated animals weighed significantly less. Tick feeding on the IrFER2 vaccinated calf was not impaired. The in vitro feeding of serum or fresh whole blood collected from the vaccinated animals did not significantly affect tick feeding success. Immunization with native I. ricinus TPEs thus conferred a strong immune response in calves and significantly reduced the feeding success of both nymphs and adults. In vitro feeding of serum or blood collected from vaccinated animals to ticks did not affect tick feeding, indicating that antibodies alone were not responsible for the observed vaccine immunity
The Complexity of Piroplasms Life Cycles
Although apicomplexan parasites of the group Piroplasmida represent commonly identified global risks to both animals and humans, detailed knowledge of their life cycles is surprisingly limited. Such a discrepancy results from incomplete literature reports, nomenclature disunity and recently, from large numbers of newly described species. This review intends to collate and summarize current knowledge with respect to piroplasm phylogeny. Moreover, it provides a comprehensive view of developmental events of Babesia, Theileria, and Cytauxzoon representative species, focusing on uniform consensus of three consecutive phases: (i) schizogony and merogony, asexual multiplication in blood cells of the vertebrate host; (ii) gamogony, sexual reproduction inside the tick midgut, later followed by invasion of kinetes into the tick internal tissues; and (iii) sporogony, asexual proliferation in tick salivary glands resulting in the formation of sporozoites. However, many fundamental differences in this general consensus occur and this review identifies variables that should be analyzed prior to further development of specific anti-piroplasm strategies, including the attractive targeting of life cycle stages of Babesia or Theileria tick vectors
Invasive potential of Borrelia burgdorferi sensu stricto ospC type L strains increases the possible disease risk to humans in the regions of their distribution
Vaccination against Bm86 Homologues in Rabbits Does Not Impair Ixodes ricinus Feeding or Oviposition
Human tick-borne diseases that are transmitted by Ixodes ricinus, such as Lyme
borreliosis and tick borne encephalitis, are on the rise in Europe.
Diminishing I. ricinus populations in nature can reduce tick exposure to
humans, and one way to do so is by developing an anti-vector vaccine against
tick antigens. Currently, there is only one anti-vector vaccine available
against ticks, which is a veterinary vaccine based on the tick antigen Bm86 in
the gut of Rhipicephalus microplus. Bm86 vaccine formulations cause a
reduction in the number of Rhipicephalus microplus ticks that successfully
feed, i.e. lower engorgement weights and a decrease in the number of
oviposited eggs. Furthermore, Bm86 vaccines reduce transmission of bovine
Babesia spp. Previously two conserved Bm86 homologues in I. ricinus ticks,
designated as Ir86-1 and Ir86-2, were described. Here we investigated the
effect of a vaccine against recombinant Ir86-1, Ir86-2 or a combination of
both on Ixodes ricinus feeding. Recombinant Ixodes ricinus Bm86 homologues
were expressed in a Drosophila expression system and rabbits were immunized
with rIr86-1, rIr86-2, a combination of both or ovalbumin as a control. Each
animal was infested with 50 female adults and 50 male adults Ixodes ricinus
and tick mortality, engorgement weights and egg mass were analyzed. Although
serum IgG titers against rIr86 proteins were elicited, no effect was found on
tick feeding between the rIr86 vaccinated animals and ovalbumin vaccinated
animals. We conclude that vaccination against Bm86 homologues in Ixodes
ricinus is not an effective approach to control Ixodes ricinus populations,
despite the clear effects of Bm86 vaccination against Rhipicephalus microplus
Calculation of the efficacy of vaccines against tick infestations on cattle
Articles in International JournalsCattle ticks are responsible for great economic losses in cattle farming worldwide, and their main control method,
chemicals, has been showing problems, whether resulting from the development of resistant strains of ticks or
environmental contamination. Research studies directed toward developing vaccines against ticks are emerging. One
way to evaluate those vaccines is to calculate the percentage of efficacy. The aim of this study was to analyze scientific
publications archived in PubMed that used this method of assessment and discuss the main factors that may affect its
calculation. Thus, 25 articles addressing this subject were selected. The percentage of efficacy was usually calculated
in one of two ways, with one considering the reduced fertility of eggs and the other not. The latter method may
underestimate the vaccine efficacy, and the most complete formula for calculating the efficacy reflects how much the
vaccine actually affects the infestation. In our view, the use of the complete formula for calculating the percentage of
efficacy is broader and more representative of the vaccine effect on the tick population.RESUMO - Carrapatos de bovinos são responsáveis por grandes perdas econômicas para a pecuária bovina mundial e seu principal
método de controle, o químico, vem apresentando problemas, seja pelo desenvolvimento de amostras de carrapatos
resistentes ou pela contaminação ambiental. Na tentativa de diminuir a utilização dos acaricidas, surgem pesquisas
direcionadas ao desenvolvimento de vacinas contra carrapatos. Uma maneira de avaliar essas vacinas é pelo cálculo de
percentagem de eficácia. O objetivo deste trabalho foi analisar as publicações científicas indexadas no PubMed que
utilizaram este método de avaliação e discutir os principais fatores que podem interferir no seu cálculo. Dessa maneira,
selecionaram-se 25 artigos que tratavam desse assunto. A percentagem de eficácia apareceu sendo calculada de duas
formas, uma considerando a redução da fertilidade dos ovos e a outra não. Essa última pode subestimar a eficiência da
vacina, e a fórmula de cálculo da eficácia mais completa representa o quanto da infestação a vacina realmente reduziu.
Em nosso entendimento, a utilização da fórmula completa para o cálculo da percentagem de eficácia é mais abrangente
e representativa do efeito da vacina na população de carrapatos
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