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AbstractWe study the modeling and forecasting of high-dimensional functional time series (HDFTS), which can be cross-sectionally correlated and temporally dependent. We introduce a decomposition of the HDFTS into two distinct components: a deterministic component and a residual component that varies over time. The decomposition is derived through the estimation of two-way functional analysis of variance. A functional time series forecasting method, based on functional principal component analysis, is implemented to produce forecasts for the residual component. By combining the forecasts of the residual component with the deterministic component, we obtain forecast curves for multiple populations. We apply the model to age- and sex-specific mortality rates in the United States, France, and Japan, in which there are 51 states, 95 departments, and 47 prefectures, respectively. The proposed method is capable of delivering more accurate point and interval forecasts in forecasting multi-population mortality than several benchmark methods considered. [ABSTRACT FROM AUTHOR]

In Colombia the agricultural sector has difficulties in the integration of technologies, due to the difficulties of the topography, very characteristic in the area of Colombian mountain ranges that pass through the main agricultural departments of the country and the limitations of human capacity; the citrus harvesting process has traditionally been done by hand, employing thousands of people who do not achieve significant yields;, thus causing an increase in production costs with an impact on harvest indicators, measured in terms of quality and productivity. This study aims to determine the impact of field slope conditions on quality indicators and indicators of effectiveness, efficiency, and loss indictors, used to evaluate the productivity of the orange harvesting process in a case study in the Department of Caldas-Colombia in order to identify opportunities for process improvement. Field information was made on orangeproducing farms with different land slopes classified into four categories. Statistically significant partnerships were identified between the efficiency, efficiency and loss indicators and the field slope conditions. In addition, some of these indicators showed inverse relationships to the slope gradient. On the contrary, the quality of the fruit is not affected by the slope conditions of the land. [ABSTRACT FROM AUTHOR]

Background Antibody (Ab) tests for SARS-CoV-2 virus allows for the estimation of incidence, level of exposure and duration of immunity acquired by a previous infection. In health workers, the hospital setting might convey a greater risk of infection. Aims To describe the frequency of immunoglobulin G (IgG) Abs (IgG-Abs) to the SARS-CoV-2 virus among workers at a third-level university hospital in Colombia. Methods In this cross-sectional study, we included medical and non-medical personnel with at least one real-time polymerase chain reaction (RT–PCR)/antigen test between March 2020 and March 2021. In April 2021, an IgG-Ab test against SARS-CoV-2 was conducted for all participants and replicated 2 weeks later in a random sample (10%). The frequency of IgG-Abs is presented based on status (positive/negative) and time elapsed since RT–PCR/antigen test (<3 months, 3–6 months, >6 months). Results We included 1021 workers (80% women, median age 34 years (interquartile range 28–42), 73% medical personnel, 23% with previous positive RT–PCR/antigen). The overall seroprevalence was 35% (95% CI 31.6–37.4, 35% in medical and 33% in non-medical personnel). For those with a previous positive RT–PCR/antigen test, the seroprevalence was 90% (<3 months), 82% (3–6 months) and 48% (>6 months). In participants with a previous negative RT–PCR/antigen test, the seroprevalence was 17% (<3 months), 21% (3–6 months) and 29% (>6 months). Conclusions High IgG-Ab positivity was found in hospital personnel, regardless of work activities. The prevalence of detectable Abs differed by previous RT–PCR/antigen status and time elapsed since the diagnostic test. [ABSTRACT FROM AUTHOR]

Dephasing—phase randomization of a quantum superposition state—is a major obstacle for the realization of high fidelity quantum logic operations. Here, we implement a two-qubit controlled-NOT gate using dynamical decoupling (DD), despite the gate time being more than 1 order of magnitude longer than the intrinsic coherence time of the system. For realizing this universal conditional quantum gate, we have devised a concatenated DD sequence that ensures robustness against imperfections of DD pulses that otherwise may destroy quantum information or interfere with gate dynamics. We compare its performance with three other types of DD sequences. These experiments are carried out using a well-controlled prototype quantum system—trapped atomic ions coupled by an effective spin-spin interaction. The scheme for protecting conditional quantum gates demonstrated here is applicable to other physical systems, such as nitrogen vacancy centers, solid state nuclear magnetic resonance, and circuit quantum electrodynamics. [ABSTRACT FROM AUTHOR]

We report on the experimental investigation of an individual pseudomolecule using trapped ions with adjustable magnetically induced 7-type coupling between spin states. Resonances of individual spins are well separated and are addressed with high fidelity. Quantum gates are carried out using microwave radiation in the presence of thermal excitation of the pseudomolecule's vibrations. Demonstrating controlled-NOT gates between non-nearest neighbors serves as a proof-of-principle of a quantum bus employing a spin chain. Combining advantageous features of nuclear magnetic resonance experiments and trapped ions, respectively, opens up a new avenue toward scalable quantum information processing. [ABSTRACT FROM AUTHOR]

Trapped atomic ions have been used successfully to demonstrate basic elements of universal quantum information processing. Nevertheless, scaling up such methods to achieve large-scale, universal quantum information processing (or more specialized quantum simulations) remains challenging. The use of easily controllable and stable microwave sources, rather than complex laser systems, could remove obstacles to scalability. However, the microwave approach has drawbacks: it involves the use of magnetic-field-sensitive states, which shorten coherence times considerably, and requires large, stable magnetic field gradients. Here we show how to overcome both problems by using stationary atomic quantum states as qubits that are induced by microwave fields (that is, by dressing magnetic-field-sensitive states with microwave fields). This permits fast quantum logic, even in the presence of a small (effective) Lamb-Dicke parameter (and, therefore, moderate magnetic field gradients). We experimentally demonstrate the basic building blocks of this scheme, showing that the dressed states are long lived and that coherence times are increased by more than two orders of magnitude relative to those of bare magnetic-field-sensitive states. This improves the prospects of microwave-driven ion trap quantum information processing, and offers a route to extending coherence times in all systems that suffer from magnetic noise, such as neutral atoms, nitrogen-vacancy centres, quantum dots or circuit quantum electrodynamic systems. [ABSTRACT FROM AUTHOR]

We measure the spatial correlation function of Bose-Einstein condensates in the cross-over region between phase-coherent and strongly phase-fluctuating condensates. We observe the continuous path from a Gaussian-like shape to an exponential-like shape characteristic of one-dimensional phase-fluctuations. The width of the spatial correlation function as a function of the temperature shows that the condensate coherence length undergoes no sharp transition between these two regimes. [ABSTRACT FROM AUTHOR]