Alkaline earth atoms in optical tweezers

We demonstrate single-shot imaging and narrow-line cooling of individual alkaline earth atoms in optical tweezers; specifically, strontium-88 atoms trapped in $515.2~\text{nm}$ light. We achieve high-fidelity single-atom-resolved imaging by detecting photons from the broad singlet transition while cooling on the narrow intercombination line, and extend this technique to highly uniform two-dimensional arrays of $121$ tweezers. Cooling during imaging is based on a previously unobserved narrow-line Sisyphus mechanism, which we predict to be applicable in a wide variety of experimental situations. Further, we demonstrate optically resolved sideband cooling of a single atom close to the motional ground state of a tweezer. Precise determination of losses during imaging indicate that the branching ratio from $^1$P$_1$ to $^1$D$_2$ is more than a factor of two larger than commonly quoted, a discrepancy also predicted by our ab initio calculations. We also measure the differential polarizability of the intercombination line in a $515.2~\text{nm}$ tweezer and achieve a magic-trapping configuration by tuning the tweezer polarization from linear to elliptical. We present calculations, in agreement with our results, which predict a magic crossing for linear polarization at $520(2)~\text{nm}$ and a crossing independent of polarization at 500.65(50)nm. Our results pave the way for a wide range of novel experimental avenues based on individually controlled alkaline earth atoms in tweezers -- from fundamental experiments in atomic physics to quantum computing, simulation, and metrology implementations

A role for low concentration reaction intermediates in the signal amplification by reversible exchange process revealed by theory and experiment

A route to monitor the involvement of less abundant species during the catalytic transfer of hyperpolarisation from parahydrogen into a substrate is detailed. It involves probing how the degree of hyperpolarisation transfer catalysis is affected by the magnetic field experienced by the catalyst during this process as a function of temperature. The resulting data allows the ready differentiation of the roles played by hard to detect and highly reactive complexes, such as [Ir(H)2(NHC)(substrate)2(methanol)]Cl, from dominant species such as [Ir(H)2(NHC)(substrate)3]Cl. The difference in behaviour results from changes in the interligand spin-spin coupling network within the active SABRE catalysts

Coupling radio propagation and weather forecast models to maximize Ka-band channel transmission rate for interplanetary missions

Deep space (DS) missions for interplanetary explorations are aimed at acquiring information about the solar system and its composition. To achieve this result a radio link is established between the space satellite and receiving stations on the Earth. Significant channel capacity must be guaranteed to such spacecraft-to-Earth link considering their large separation distance as well. Terrestrial atmospheric impairments on the space-to-Earth propagating signals are the major responsible for the signal degradation thus reducing the link’s channel temporal availability. Considering the saturation and the limited bandwidth of the conventional systems used working at X-band (around 8.4 GHz), frequencies above Ku-band (12-18 GHz) are being used and currently explored for next future DS missions. For example, the ESA mission EUCLID, planned to be launched in 2020 to reach Sun-Earth Lagrange point L2, will use the K-band (at 25.5-27 GHz). The BepiColombo (BC) ESA mission to Mercury, planned to be launched in 2016, will use Ka-band (at 32-34 GHz) with some modules operating at X-band too. The W-band is also being investigated for space communications (Lucente et al., IEEE Systems J., 2008) as well as near-infrared band for DS links (Luini at al., 3rd IWOW, 2014; Cesarone et al., ICSOS, 2011). If compared with X-band channels, K-band and Ka-band can provide an appealing data rate and signal-to-noise ratio in free space due to the squared-frequency law increase of antenna directivity within the downlink budget (for the same physical antenna size). However, atmospheric path attenuation can be significant for higher frequencies since the major source of transmission outage is not only caused by convective rainfall, as it happens for lower frequencies too, but even non-precipitating clouds and moderate precipitation produced by stratiform rain events are detrimental. This means that accurate channel models are necessary for DS mission data link design at K and Ka band. A physical approach can offer advanced radiopropagation models to take into account the effects due to atmospheric gases, clouds and precipitation. The objective of this work is to couple a weather forecast numerical model with a microphysically- oriented radiopropagation model, providing a description of the atmospheric state and of its effects on a DS downlink. This work is developed in the framework of the RadioMeteorological Operations Planner (RMOP) program, aimed at performing a feasibility study for the BC mission (Biscarini et al., EuCAP 2014). The RMOP chain for the link budget computation is composed by three modules: weather forecast (WFM), radio propagation (RPM) and downlink budget (DBM). WFM is aimed at providing an atmospheric state vector. Among the available weather forecast models, for RMOP purposes we have used the Mesoscale Model 5. The output of the WFM is the input of the RPM for the computation of the atmospheric attenuation and sky-noise temperature at the receiving ground station antenna. RPM makes use of radiative transfer solver based on the Eddington approximations well as accurate scattering models. Time series of attenuation and sky-noise temperature coming from the RPM are converted into probability density functions and then ingested by the DBM to compute the received data volume (DV). Using the BC mission as a reference test case for the Ka-band ground station at Cebreros (Spain), this work will show the advantages of using a coupled WFM-RPM approach with respect to climatological statistics in a link budget optimization procedure. The signal degradation due to atmospheric effects in DS links in terms of received DV will be also investigated not only at Ka band, but also at X, K and W for intercomparison. The quality of the DS downlink will be given in terms of received DV and the results at different frequencies compared showing the respective advantages and drawbacks

Partial purification and MALDI-TOF MS analysis of UN1, a tumor antigen membrane glycoprotein.

UN1 is a membrane glycoprotein that is expressed in immature human thymocytes, a subpopulation of peripheral T lymphocytes, the HPB acute lymphoblastic leukemia (ALL) T-cell line and fetal thymus. We previously reported the isolation of a monoclonal antibody (UN1 mAb) recognizing the UN1 protein that was classified as "unclustered" at the 5th and 6th International Workshop and Conference on Human Leukocyte Differentiation Antigens. UN1 was highly expressed in breast cancer tissues and was undetected in non-proliferative lesions and in normal breast tissues, indicating a role for UN1 in the development of a tumorigenic phenotype of breast cancer cells. In this study, we report a partial purification of the UN1 protein from HPB-ALL T cells by anion-exchange chromatography followed by immunoprecipitation with the UN1 mAb and MALDI-TOF MS analysis. This analysis should assist in identifying the amino acid sequence of UN

Parricide and Violence against Parents: A Cross-Cultural View across Past and Present

Parricide and Violence Against Parents takes a historical and criminological approach to the research on parricide and violence against parents, placing the research in the context of social development from the 1500s to contemporary society, and giving a global overview and comparison. The book examines parricide and violence against parents as historically and culturally sensitive phenomena. It offers evidence on a seemingly rare subject from different eras, areas, and cultures, and then uses the cross-disciplinary data to produce a new, systematic insight for the reader. Case studies shift the discussion from the contemporary focus on adolescent to parent abuse, to examining the sources of conflict during life cycles of parents and their offspring. A historical approach illuminates the variations in conflicts between parents and their offspring that are shaped by the life stages of the victims and offenders themselves across time. The book argues that parental authority has been marked by property ownership and tax paying responsibilities throughout history. The continued possession of property resulted in power, the reluctance to part with it, becoming a notable source of conflict across generations within families. Parental authority was protected by means of heavy penalties and punishments and didactic teachings in almost every society at every stage of historical development. It was also challenged constantly by children as a part of their coming into adulthood. The abuse of parents has often been connected to situations where adult children were prevented from gaining the amount of independence appropriate to their position in life. This led to disputes over authority and the legitimate grounds for that authority. Offering an insight into complicated and interconnected histories of generational conflicts and how they affect modern families in different parts of the world, this book will be of great interest to students and scholars of criminology, history of crime, history of the family, family violence, homicide studies, gender studies, history of emotions, political violence, and social work.Peer reviewe

Self-efficacy mechanism at work : the context of environmental volunteer travel

This article contributes the first utilization of Bandura’s self-efficacy (SE) mechanism in the context of environmental volunteer travel demonstrating how environmental stewardship, hedonic experience, and environmental SE relate to one another in this particular settin

Mixed-Mode Sensitivity Analysis of a Combined Differential and Common Mode Active Receiving Antenna Providing Near-Hemispherical Field-of-View Coverage

A theoretical framework for a mixed differential and common mode sensitivity analysis of active receiving antennas is presented, which includes the derivation of a novel set of noise parameters for dual-mode balanced amplifiers. The analysis is applied to an example of a mixed-mode active wire antenna design, consisting of an integrated monopole and dipole structure. Results of numerical simulations and experimental measurements are presented which show that, for a single-polarized design, the judicious use of both differential and common modes enables the field-of-view coverage to be extended over the entire hemisphere with a variation in receiving sensitivity of less than 3 dB in the E-plane