The quantum speed up as advanced knowledge of the solution

With reference to a search in a database of size N, Grover states: "What is the reason that one would expect that a quantum mechanical scheme could accomplish the search in O(square root of N) steps? It would be insightful to have a simple two line argument for this without having to describe the details of the search algorithm". The answer provided in this work is: "because any quantum algorithm takes the time taken by a classical algorithm that knows in advance 50% of the information that specifies the solution of the problem". This empirical fact, unnoticed so far, holds for both quadratic and exponential speed ups and is theoretically justified in three steps: (i) once the physical representation is extended to the production of the problem on the part of the oracle and to the final measurement of the computer register, quantum computation is reduction on the solution of the problem under a relation representing problem-solution interdependence, (ii) the speed up is explained by a simple consideration of time symmetry, it is the gain of information about the solution due to backdating, to before running the algorithm, a time-symmetric part of the reduction on the solution; this advanced knowledge of the solution reduces the size of the solution space to be explored by the algorithm, (iii) if I is the information acquired by measuring the content of the computer register at the end of the algorithm, the quantum algorithm takes the time taken by a classical algorithm that knows in advance 50% of I, which brings us to the initial statement.Comment: 23 pages, to be published in IJT

On the half-life of 44Ti by results in meteorites

Measurements of the 44Ti half-life display a large spread ranging from 46.4 to 66.6 years. The activity of this radioisotope measured in eight meteorites (chondrites) fell in the time interval 1883-1992 and calculated at the time of fall by the different values of T1O2 shows that the shorter values are not reliable, if it is assumed that the average cosmic-ray intensity has remained the same during the past two centuries. The low activity of the cosmogenic isotope 44Ti has been determined by means of a selective Ge-NaI (Tl) g-spectrometer with a very low background (about 1 count per day in the g-peak at 1157 keV of 44Sc in equilibrium with its parent 44Ti). The high stability of this system allows long-lasting runs (A107 s ), in order to achieve the standard deviation of counting up to A10%. PACS 94.40.Vf – Cosmic-ray effects in meteorites and terrestrial matter

Experimental noise-resistant Bell-inequality violations for polarization-entangled photons

We experimentally demonstrate that violations of Bell's inequalities for two-photon polarization-entangled states with colored noise are extremely robust, whereas this is not the case for states with white noise. Controlling the amount of noise by using the timing compensation scheme introduced by Kim et al. [Phys. Rev. A 67, 010301(R) (2003)], we have observed violations even for states with very high noise, in excellent agrement with the predictions of Cabello et al. [Phys. Rev. A 72, 052112 (2005)].Comment: REVTeX4, 5 pages, 4 figure

Cosmogenic radionuclides and tracks in the fresh fall portales valley

This article does not have an abstract

CD80 and CD86 Differentially Regulate Mechanical Interactions of T-Cells with Antigen-Presenting Dendritic Cells and B-Cells

10.1371/journal.pone.0045185PLoS ONE79

Using alternative or direct anthropometric measurements to assess risk for malnutrition in nursing homes.

AbstractObjectiveThe aim of this study was to use the Malnutrition Universal Screening Tool (MUST) to assess the applicability of alternative versus direct anthropometric measurements for evaluating the risk for malnutrition in older individuals living in nursing homes (NHs).MethodsWe conducted a cross-sectional survey in 67 NHs in Tuscany, Italy. We measured the weight, standing height (SH), knee height (KH), ulna length (UL), and middle-upper-arm circumference of 641 NH residents. Correlations between the different methods for calculating body mass index (BMI; using direct or alternative measurements) were evaluated by the intraclass correlation coefficient and the Bland-Altman method; agreement in the allocation of participants to the same risk category was assessed by squared weighted kappa statistic and indicators of internal relative validity.ResultsThe intraclass correlation coefficient for BMI calculated using KH was 0.839 (0.815–0.861), whereas those calculated by UL were 0.890 (0.872–0.905). The limits of agreement were ±6.13 kg/m2 using KH and ±4.66 kg/m2 using UL. For BMI calculated using SH, 79.9% of the patients were at low risk, 8.1% at medium risk, and 12.2% at high risk for malnutrition. The agreement between this classification and that obtained using BMI calculated by alternative measurements was “fair-good.”ConclusionWhen it is not possible to determine risk category by using SH, we suggest using the alternative measurements (primarily UL, due to its highest sensitivity) to predict the height and to compare these evaluations with those obtained by using middle-upper-arm-circumference to predict the BMI

Fibroblasts from patients with Diamond-Blackfan anaemia show abnormal expression of genes involved in protein synthesis, amino acid metabolism and cancer

Background: Diamond-Blackfan anaemia (DBA) is a rare inherited red cell hypoplasia characterised by a defect in the maturation of erythroid progenitors and in some cases associated with malformations. Patients have an increased risk of solid tumors. Mutations have been found in several ribosomal protein (RP) genes, i.e RPS19, RPS24, RPS17, RPL5, RPL11, RPL35A. Studies in haematopoietic progenitors from patients show that haplo-insufficiency of an RP impairs rRNA processing and ribosome biogenesis. DBA lymphocytes show reduced protein synthesis and fibroblasts display abnormal rRNA processing and impaired proliferation. Results: To evaluate the involvement of non-haematopoietic tissues in DBA, we have analysed global gene expression in fibroblasts from DBA patients compared to healthy controls. Microarray expression profiling using Affymetrix GeneChip Human Genome U133A 2.0 Arrays revealed that 421 genes are differentially expressed in DBA patient fibroblasts. These genes include a large cluster of ribosomal proteins and factors involved in protein synthesis and amino acid metabolism, as well as genes associated to cell death, cancer and tissue development. Conclusion: This analysis reports for the first time an abnormal gene expression profile in a non-haematopoietic cell type in DBA. These data support the hypothesis that DBA may be due to a defect in general or specific protein synthesis. \ua9 2009 Avondo et al; licensee BioMed Central Ltd

Heliospheric behavior in the past by Titanium-44 measurement in chondrites

This article does not have an abstract