We adapt the robust phase estimation algorithm to the evaluation of energy differences between two eigenstates using a quantum computer. This approach does not require controlled unitaries between ...auxiliary and system registers or even a single auxiliary qubit. As a proof of concept, we calculate the energies of the ground state and low-lying electronic excitations of a hydrogen molecule in a minimal basis on a cloud quantum computer. The denominative robustness of our approach is then quantified in terms of a high tolerance to coherent errors in the state preparation and measurement. Conceptually, we note that all quantum phase estimation algorithms ultimately evaluate eigenvalue differences.
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The article describes the main achievements of the NUMEN project together with an updated and detailed overview of the related R&D activities and theoretical developments. NUMEN proposes an ...innovative technique to access the nuclear matrix elements entering the expression of the lifetime of the double beta decay by cross section measurements of heavy-ion induced Double Charge Exchange (DCE) reactions. Despite the fact that the two processes, namely neutrinoless double beta decay and DCE reactions, are triggered by the weak and strong interaction respectively, important analogies are suggested. The basic point is the coincidence of the initial and final state many-body wave functions in the two types of processes and the formal similarity of the transition operators. First experimental results obtained at the INFN-LNS laboratory for the
40
Ca(
18
O,
18
Ne)
40
Ar reaction at 270MeV give an encouraging indication on the capability of the proposed technique to access relevant quantitative information. The main experimental tools for this project are the K800 Superconducting Cyclotron and MAGNEX spectrometer. The former is used for the acceleration of the required high resolution and low emittance heavy-ion beams and the latter is the large acceptance magnetic spectrometer for the detection of the ejectiles. The use of the high-order trajectory reconstruction technique, implemented in MAGNEX, allows to reach the experimental resolution and sensitivity required for the accurate measurement of the DCE cross sections at forward angles. However, the tiny values of such cross sections and the resolution requirements demand beam intensities much larger than those manageable with the present facility. The on-going upgrade of the INFN-LNS facilities in this perspective is part of the NUMEN project and will be discussed in the article.
Decisions made by mammals and birds are often temporally extended. They require planning and sampling of decision-relevant information. Our understanding of such decision-making remains in its ...infancy compared with simpler, forced-choice paradigms. However, recent advances in algorithms supporting planning and information search provide a lens through which we can explain neural and behavioral data in these tasks. We review these advances to obtain a clearer understanding for why planning and curiosity originated in certain species but not others; how activity in the medial temporal lobe, prefrontal and cingulate cortices may support these behaviors; and how planning and information search may complement each other as means to improve future action selection.
The fallopian tube epithelium (FTE) is one of the progenitor populations for high-grade serous ovarian cancer (HGSC). Loss of PAX2 is the earliest known molecular aberration in the FTE occurring in ...serous carcinogenesis followed by a mutation in p53. Pathological studies report consistent loss of PAX2 in benign lesions as well as serous tumors. In the current study, the combined loss of PAX2 and expression of the R273H p53 mutant protein in murine oviductal epithelial (MOE) cells enhanced proliferation and growth in soft agar in vitro but was insufficient to drive tumorigenesis in vivo. A serially passaged model was generated to investigate the role of aging, but was also insufficient to drive tumorigenesis. These models recapitulate early benign lesions and suggest that a latency period exists between loss of PAX2, p53 mutation and tumor formation. Stathmin and fut8 were identified as downstream targets regulated by loss of PAX2 and mutation of p53 in MOE cells. Re-expression of PAX2 in PAX2-null human HGSC cells reduced cell survival via apoptosis. Phosphatase and tensin homolog (PTEN)
negatively regulated PAX2 expression and stable re-expression of PAX2 in MOE:PTEN
cells significantly reduced proliferation and peritoneal tumor formation in athymic nude mice. PAX2 was determined to be a direct transcriptional target that was activated by wild-type p53, whereas mutant p53 inhibited PAX2 transcription in MOE cells. A small molecule screen using the proximal PAX2 promoter driving luciferase identified four small molecules that were able to enhance PAX2 mRNA expression in MOE cells. PAX2 re-expression in HGSC cells and PTEN-deficient oviductal tumors may have the potential to induce apoptosis. In summary, mutant p53 and PTEN loss negatively regulated PAX2 and PAX2 re-expression in HGSC cells induced cell death.
Forests are major components of the global carbon cycle, providing substantial feedback to atmospheric greenhouse gas concentrations. Our ability to understand and predict changes in the forest ...carbon cycle--particularly net primary productivity and carbon storage--increasingly relies on models that represent biological processes across several scales of biological organization, from tree leaves to forest stands. Yet, despite advances in our understanding of productivity at the scales of leaves and stands, no consensus exists about the nature of productivity at the scale of the individual tree, in part because we lack a broad empirical assessment of whether rates of absolute tree mass growth (and thus carbon accumulation) decrease, remain constant, or increase as trees increase in size and age. Here we present a global analysis of 403 tropical and temperate tree species, showing that for most species mass growth rate increases continuously with tree size. Thus, large, old trees do not act simply as senescent carbon reservoirs but actively fix large amounts of carbon compared to smaller trees; at the extreme, a single big tree can add the same amount of carbon to the forest within a year as is contained in an entire mid-sized tree. The apparent paradoxes of individual tree growth increasing with tree size despite declining leaf-level and stand-level productivity can be explained, respectively, by increases in a tree's total leaf area that outpace declines in productivity per unit of leaf area and, among other factors, age-related reductions in population density. Our results resolve conflicting assumptions about the nature of tree growth, inform efforts to undertand and model forest carbon dynamics, and have additional implications for theories of resource allocation and plant senescence.
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Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Chronic lymphocytic leukemia (CLL) can be immunosuppressive in humans and mice, and CLL cells share multiple phenotypic markers with regulatory B cells that are competent to produce interleukin ...(IL)-10 (B10 cells). To identify functional links between CLL cells and regulatory B10 cells, the phenotypes and abilities of leukemia cells from 93 patients with overt CLL to express IL-10 were assessed. CD5(+) CLL cells purified from 90% of the patients were IL-10-competent and secreted IL-10 following appropriate ex vivo stimulation. Serum IL-10 levels were also significantly elevated in CLL patients. IL-10-competent cell frequencies were higher among CLLs with IgV(H) mutations, and correlated positively with TCL1 expression. In the TCL1-transgenic (TCL1-Tg) mouse model of CLL, IL-10-competent B cells with the cell surface phenotype of B10 cells expanded significantly with age, preceding the development of overt, CLL-like leukemia. Malignant CLL cells in TCL1-Tg mice also shared immunoregulatory functions with mouse and human B10 cells. Serum IL-10 levels varied in TCL1-Tg mice, but in vivo low-dose lipopolysaccharide treatment induced IL-10 expression in CLL cells and high levels of serum IL-10. Thus, malignant IL-10-competent CLL cells exhibit regulatory functions comparable to normal B10 cells that may contribute to the immunosuppression observed in patients and TCL1-Tg mice.
Dependence on drugs has enduring effects on drug intake and relapse. The role of choice in enhanced susceptibility to drug use in drug dependence has been little studied. Here we determine the ...effects of alcohol dependence on the choice between alcohol and a non-drug reward, saccharin, using the discrete choice model in food-restricted male rats. We trained rats to self-administer alcohol (12% w/v) and saccharin (0.05, 0.1%), tested their choice of alcohol vs. saccharin, and determined the effects of deprivation and intertrial interval (ITI) duration on choice. We then determined the effects of alcohol dependence, induced by repeated intermittent exposure to alcohol vapor on choice of alcohol vs. saccharin (0.1%) in discrete choice trials as well as on the effects of adulteration of alcohol with quinine on choice. We trained another group of rats to self-administer intravenous (i.v.) nicotine (0.03 mg/kg/infusion) and oral saccharin (0.1%), determined their choice, and examined the roles of ITI duration and concurrent access on choice. Rats chose equivalent amounts of 0.05% saccharin and 12% alcohol, showed a stronger choice for 0.1% saccharin, and alcohol and saccharin choice were modestly decreased and increased, respectively, by deprivation. Alcohol dependence led to profound increases in the choice of alcohol over saccharin while adulteration of alcohol with quinine did not affect choice in non-dependent or dependent rats. Rats showed marked choice for 0.1% saccharin over i.v. nicotine. The strong effect that dependence had on alcohol choice is an important validation of the discrete choice procedure.
Sensory neurons have recently emerged as components of the tumor microenvironment. Nevertheless, whether sensory neuronal activity is important for tumor progression remains unknown. Here we used ...Designer Receptors Exclusively Activated by a Designer Drug (DREADD) technology to inhibit or activate sensory neurons' firing within the melanoma tumor. Melanoma growth and angiogenesis were accelerated following inhibition of sensory neurons' activity and were reduced following overstimulation of these neurons. Sensory neuron-specific overactivation also induced a boost in the immune surveillance by increasing tumor-infiltrating anti-tumor lymphocytes, while reducing immune-suppressor cells. In humans, a retrospective in silico analysis of melanoma biopsies revealed that increased expression of sensory neurons-related genes within melanoma was associated with improved survival. These findings suggest that sensory innervations regulate melanoma progression, indicating that manipulation of sensory neurons' activity may provide a valuable tool to improve melanoma patients' outcomes.
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