Remittances and morality: family obligations, development, and the ethical demands of migration

Remittances have moral dimensions that, albeit implicitly addressed in migration literature, have not yet been the focus of explicit attention and analysis by social scientists. Building on recent developments in the anthropology of ethics and morality, this article proposes theoretical and analytical pathways to address this important but often neglected aspect of remittances. It does so mainly via a critical analysis of existing scholarship on remittances, and ethnographic data drawn from research among Cuban migrants in Cuba and Spain. The reflexive scrutiny of scholars’ moral assumptions about remittances opens the way for the study of the moral dilemmas and ethical demands articulated by remittance senders and recipients. Family roles and obligations, and the uses of the money sent by migrants, are identified as key areas of moral difficulty. Their analysis shows how remittances inform moral reassessments of family relations, individual responsibility, economic practice, and development. The notion of ‘moral remittances’ is proposed as a heuristic comparative tool that serves to illuminate the moral aspects of remittances. This notion is put into perspective to complement and reconsider more metaphorical takes on remittances, notably the concept of ‘social remittances’, of which it helps reveal some epistemological limitations while opening future research avenues.info:eu-repo/semantics/acceptedVersio

Lorentz Transformations as Lie-Poisson Symmetries

We write down the Poisson structure for a relativistic particle where the Lorentz group does not act canonically, but instead as a Poisson-Lie group. In so doing we obtain the classical limit of a particle moving on a noncommutative space possessing $SL_q(2,C)$ invariance. We show that if the standard mass shell constraint is chosen for the Hamiltonian function, then the particle interacts with the space-time. We solve for the trajectory and find that it originates and terminates at singularities.Comment: 18 page

A superconducting absolute spin valve

A superconductor with a spin-split excitation spectrum behaves as an ideal ferromagnetic spin-injector in a tunneling junction. It was theoretical predicted that the combination of two such spin-split superconductors with independently tunable magnetizations, may be used as an ideal $absolute$ spin-valve. Here we report on the first switchable superconducting spin-valve based on two EuS/Al bilayers coupled through an aluminum oxide tunnel barrier. The spin-valve shows a relative resistance change between the parallel and antiparallel configuration of the EuS layers up to 900% that demonstrates a highly spin-polarized currents through the junction. Our device may be pivotal for realization of thermoelectric radiation detectors, logical element for a memory cell in cryogenics superconductor-based computers and superconducting spintronics in general.Comment: 6 pages, 4 color figures, 1 tabl

39-K Bose-Einstein condensate with tunable interactions

We produce a Bose-Einstein condensate of 39-K atoms. Condensation of this species with naturally small and negative scattering length is achieved by a combination of sympathetic cooling with 87-Rb and direct evaporation, exploiting the magnetic tuning of both inter- and intra-species interactions at Feshbach resonances. We explore tunability of the self-interactions by studying the expansion and the stability of the condensate. We find that a 39-K condensate is interesting for future experiments requiring a weakly interacting Bose gas.Comment: 5 page

Revealing the magnetic proximity effect in EuS/Al bilayers through superconducting tunneling spectroscopy

A ferromagnetic insulator attached to a superconductor is known to induce an exchange splitting of the Bardeen-Cooper-Schrieffer (BCS) singularity by a magnitude proportional to the magnetization, and penetrating into the superconductor to a depth comparable with the superconducting coherence length. We study this long-range magnetic proximity effect in EuS/Al bilayers and find that the exchange splitting of the BCS peaks is present already in the unpolarized state of the ferromagnetic insulator (EuS), and is being further enhanced when magnetizing the sample by a magnetic field. The measurement data taken at the lowest temperatures feature a high contrast which has allowed us to relate the line shape of the split BCS conductance peaks to the characteristic magnetic domain structure of the EuS layer in the unpolarized state. These results pave the way to engineering triplet superconducting correlations at domain walls in EuS/Al bilayers. Furthermore, the hard gap and clear splitting observed in our tunneling spectroscopy measurements indicate that EuS/Al bilayers are excellent candidates for substituting strong magnetic fields in experiments studying Majorana bound states.Comment: 9 pages, 4 color figure

Observation of Feshbach resonances in an ultracold gas of 52{}^{52}Cr

We have observed Feshbach resonances in elastic collisions between ultracold ${}^{52}$Cr atoms. This is the first observation of collisional Feshbach resonances in an atomic species with more than one valence electron. The zero nuclear spin of ${}^{52}$Cr and thus the absence of a Fermi-contact interaction leads to regularly-spaced resonance sequences. By comparing resonance positions with multi-channel scattering calculations we determine the s-wave scattering length of the lowest $^{2S+1}\Sigma_{g}^{+}$ potentials to be \unit[112(14)]{a_0}, \unit[58(6)]{a_0} and -\unit[7(20)]{a_0} for S=6, 4, and 2, respectively, where a_{0}=\unit[0.0529]{nm}.Comment: 4 pages, 2 figures, 1 tabl

Feshbach resonances in ultracold K(39)

We discover several magnetic Feshbach resonances in collisions of ultracold K(39) atoms, by studying atom losses and molecule formation. Accurate determination of the magnetic-field resonance locations allows us to optimize a quantum collision model for potassium isotopes. We employ the model to predict the magnetic-field dependence of scattering lengths and of near-threshold molecular levels. Our findings will be useful to plan future experiments on ultracold potassium atoms and molecules.Comment: 7 pages, 6 figure

Collisional and molecular spectroscopy in an ultracold Bose-Bose mixture

The route toward a Bose-Einstein condensate of dipolar molecules requires the ability to efficiently associate dimers of different chemical species and transfer them to the stable rovibrational ground state. Here, we report on recent spectroscopic measurements of two weakly bound molecular levels and newly observed narrow d-wave Feshbach resonances. The data are used to improve the collisional model for the Bose-Bose mixture 41K87Rb, among the most promising candidates to create a molecular dipolar BEC.Comment: 13 pages, 3 figure

Precise determination of 6^6Li cold collision parameters by radio-frequency spectroscopy on weakly bound molecules

We employ radio-frequency spectroscopy on weakly bound $^6$Li$_2$ molecules to precisely determine the molecular binding energies and the energy splittings between molecular states for different magnetic fields. These measurements allow us to extract the interaction parameters of ultracold $^6$Li atoms based on a multi-channel quantum scattering model. We determine the singlet and triplet scattering lengths to be $a_s=45.167(8)a_0$ and $a_t=-2140(18)a_0$ (1 $a_0$ = 0.0529177 nm), and the positions of the broad Feshbach resonances in the energetically lowest three $s-$wave scattering channels to be 83.41(15) mT, 69.04(5) mT, and 81.12(10) mT

Factors Influencing Recovery From Pediatric Stroke Based on Discussions From a UK-Based Online Stroke Community: Qualitative Thematic Study.

BACKGROUND: The incidence of stroke in children is low, and pediatric stroke rehabilitation services are less developed than adult ones. Survivors of pediatric stroke have a long poststroke life expectancy and therefore have the potential to experience impairments from their stroke for many years. However, there are relatively few studies characterizing these impairments and what factors facilitate or counteract recovery. OBJECTIVE: This study aims to characterize the main barriers to and facilitators of recovery from pediatric stroke. A secondary aim was to explore whether these factors last into adulthood, whether they change, or if new factors impacting recovery emerge in adulthood. METHODS: We performed a qualitative thematic analysis based on posts from a population of participants from a UK-based online stroke community, active between 2004 and 2011. The analysis focused on users who talked about their experiences with pediatric stroke, as identified by a previous study. The posts were read by 3 authors, and factors influencing recovery from pediatric stroke were mapped into 4 areas: medical, physical, emotional, and social. Factors influencing recovery were divided into short-term and long-term factors. RESULTS: There were 425 posts relating to 52 survivors of pediatric stroke. Some survivors of stroke posted for themselves, while others were talked about by a third party (mostly parents; 31/35, 89% mothers). In total, 79% (41/52) of survivors of stroke were aged ≤18 years and 21% (11/52) were aged >18 years at the time of posting. Medical factors included comorbidities as a barrier to recovery. Medical interventions, such as speech and language therapy and physiotherapy, were also deemed useful. Exercise, particularly swimming, was deemed a facilitator. Among physical factors, fatigue and chronic pain could persist decades after a stroke, with both reported as a barrier to feeling fully recovered. Tiredness could worsen existing stroke-related impairments. Other long-standing impairments were memory loss, confusion, and dizziness. Among emotional factors, fear and uncertainty were short-term barriers, while positivity was a major facilitator in both short- and long-term recovery. Anxiety, grief, and behavioral problems hindered recovery. The social barriers were loneliness, exclusion, and hidden disabilities not being acknowledged by third parties. A good support network and third-party support facilitated recovery. Educational services were important in reintegrating survivors into society. Participants reported that worrying about losing financial support, such as disability allowances, and difficulties in obtaining travel insurance and driving licenses impacted recovery. CONCLUSIONS: The lived experience of survivors of pediatric stroke includes long-term hidden disabilities and barriers to rehabilitation. These are present in different settings, such as health care, schools, workplaces, and driving centers. Greater awareness of these issues by relevant professional groups may help ameliorate them