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1.
Nature ; 607(7918): 260-265, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35831598

RESUMO

In spite of the high-density and strongly correlated nature of the atomic nucleus, experimental and theoretical evidence suggests that around particular 'magic' numbers of nucleons, nuclear properties are governed by a single unpaired nucleon1,2. A microscopic understanding of the extent of this behaviour and its evolution in neutron-rich nuclei remains an open question in nuclear physics3-5. The indium isotopes are considered a textbook example of this phenomenon6, in which the constancy of their electromagnetic properties indicated that a single unpaired proton hole can provide the identity of a complex many-nucleon system6,7. Here we present precision laser spectroscopy measurements performed to investigate the validity of this simple single-particle picture. Observation of an abrupt change in the dipole moment at N = 82 indicates that, whereas the single-particle picture indeed dominates at neutron magic number N = 82 (refs. 2,8), it does not for previously studied isotopes. To investigate the microscopic origin of these observations, our work provides a combined effort with developments in two complementary nuclear many-body methods: ab initio valence-space in-medium similarity renormalization group and density functional theory (DFT). We find that the inclusion of time-symmetry-breaking mean fields is essential for a correct description of nuclear magnetic properties, which were previously poorly constrained. These experimental and theoretical findings are key to understanding how seemingly simple single-particle phenomena naturally emerge from complex interactions among protons and neutrons.

2.
Nature ; 581(7809): 396-400, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32461650

RESUMO

Molecular spectroscopy offers opportunities for the exploration of the fundamental laws of nature and the search for new particle physics beyond the standard model1-4. Radioactive molecules-in which one or more of the atoms possesses a radioactive nucleus-can contain heavy and deformed nuclei, offering high sensitivity for investigating parity- and time-reversal-violation effects5,6. Radium monofluoride, RaF, is of particular interest because it is predicted to have an electronic structure appropriate for laser cooling6, thus paving the way for its use in high-precision spectroscopic studies. Furthermore, the effects of symmetry-violating nuclear moments are strongly enhanced5,7-9 in molecules containing octupole-deformed radium isotopes10,11. However, the study of RaF has been impeded by the lack of stable isotopes of radium. Here we present an experimental approach to studying short-lived radioactive molecules, which allows us to measure molecules with lifetimes of just tens of milliseconds. Energetically low-lying electronic states were measured for different isotopically pure RaF molecules using collinear resonance ionisation at the ISOLDE ion-beam facility at CERN. Our results provide evidence of the existence of a suitable laser-cooling scheme for these molecules and represent a key step towards high-precision studies in these systems. Our findings will enable further studies of short-lived radioactive molecules for fundamental physics research.

3.
Phys Rev Lett ; 133(3): 033003, 2024 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-39094143

RESUMO

We present a novel technique to probe electroweak nuclear properties by measuring parity violation (PV) in single molecular ions in a Penning trap. The trap's strong magnetic field Zeeman shifts opposite-parity rotational and hyperfine molecular states into near degeneracy. The weak interaction-induced mixing between these degenerate states can be larger than in atoms by more than 12 orders of magnitude, thereby vastly amplifying PV effects. The single molecule sensitivity would be suitable for applications to nuclei across the nuclear chart, including rare and unstable nuclei.

4.
Actas Dermosifiliogr ; 2024 Mar 06.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-38452894

RESUMO

BACKGROUND: There is a need for epidemiological and incidence data on the occurrence of basal cell carcinoma (BCC) in Spain. OBJECTIVES: Our study was designed to retrospectively retrieve cases from our computer databases from 2010 through 2016 to provide updated data on the actual incidence of BCC in Valencia, eastern Spain. MATERIAL AND METHODS: This was an epidemiological study on basal cell carcinoma conducted in Valencia, eastern Spain. We analyzed a total of 2171 patients and 4047 tumors, and gathered data to estimate the actual incidence of BBC in our region. RESULTS AND CONCLUSIONS: Our study confirmed that the incidence of BCC is much higher than previously reported. We calculated a crude incidence of 410.38 BCCs/100 000 person-years, an adjusted rate for the European population of 256.98 BCCs/100 000 person-years, and an adjusted rate for the world population of 196.26 BCCs/100 000 person-years. Risk is up to 29.49% higher for men (464.07 cases/100 000 person-years vs 358.40 cases/100 000 person-years for women). Incidence also increases by an annual 3.91% (a significantly higher annual incidence of 8.28% in women vs a 0.92% annual incidence in men). Overall, the lifetime risk for developing a BCC is 5.8% (5.02% in women and 7% in men).

5.
Actas Dermosifiliogr ; 2024 Sep 09.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-39260609

RESUMO

BACKGROUND: there is a need for epidemiological and incidence data on the occurrence of basal cell carcinoma (BCC) in Spain. OBJECTIVES: our study was designed to retrospectively retrieve cases from our computer databases from 2010 through 2016 to provide updated data on the actual incidence of BCC in Valencia, eastern Spain. METHODS: this was an epidemiological study on basal cell carcinoma conducted in Valencia, eastern Spain. We analyzed a total of 2171 patients and 4047 tumors, and gathered data to estimate the actual incidence of BBC in our region. RESULTS AND CONCLUSIONS: our study confirmed that the incidence of BCC is much higher than previously reported. We calculated a crude incidence of 410.38 BCCs/100 000 person-years, an adjusted rate for the European population of 256.98 BCCs/100 000 person-years, and an adjusted rate for the world population of 196.26 BCCs/100 000 person-years.Risk is up to 29.49% higher for men (464.07 cases/100 000 person-years vs 358.40 cases/100 000 person-years for women).Incidence also increases by an annual 3.91% (a significantly higher annual incidence of 8.28% in women vs a 0.92% annual incidence in men).Overall, the lifetime risk for developing a BCC is 5.8% (5.02% in women and 7% in men).

6.
Actas Dermosifiliogr ; 2024 Jul 18.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-39032779

RESUMO

It is necessary to identify which factors or comorbidities are associated with more severe hidradenitis suppurativa, aiming to identify which patients may benefit more from early systemic treatment or a more aggressive approach. A retrospective study was conducted, including patients diagnosed with HS at the dermatology department of a Spanish hospital over a 5-year period. A total of 322 patients were included. A relationship was found between diagnostic delay, the presence of acne conglobata, pilonidal sinus, cardiovascular risk factors (hypertension, dyslipidemia, and/or diabetes mellitus) and more severe HS. No significant relationship was found between psychiatric comorbidities and the severity of the HS. The presence of perianal or truncal involvement was significantly associated with severe HS. Female sex and the presence of a family history of HS were associated with an earlier onset of the disease.

7.
Phys Rev Lett ; 131(22): 222502, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-38101341

RESUMO

Collinear laser spectroscopy was performed on the isomer of the aluminium isotope ^{26m}Al. The measured isotope shift to ^{27}Al in the 3s^{2}3p ^{2}P_{3/2}^{○}→3s^{2}4s ^{2}S_{1/2} atomic transition enabled the first experimental determination of the nuclear charge radius of ^{26m}Al, resulting in R_{c}=3.130(15) fm. This differs by 4.5 standard deviations from the extrapolated value used to calculate the isospin-symmetry breaking corrections in the superallowed ß decay of ^{26m}Al. Its corrected Ft value, important for the estimation of V_{ud} in the Cabibbo-Kobayashi-Maskawa matrix, is thus shifted by 1 standard deviation to 3071.4(1.0) s.

8.
Phys Rev Lett ; 127(19): 192501, 2021 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-34797155

RESUMO

The changes in the mean-square charge radius (relative to ^{209}Bi), magnetic dipole, and electric quadrupole moments of ^{187,188,189,191}Bi were measured using the in-source resonance-ionization spectroscopy technique at ISOLDE (CERN). A large staggering in radii was found in ^{187,188,189}Bi^{g}, manifested by a sharp radius increase for the ground state of ^{188}Bi relative to the neighboring ^{187,189}Bi^{g}. A large isomer shift was also observed for ^{188}Bi^{m}. Both effects happen at the same neutron number, N=105, where the shape staggering and a similar isomer shift were observed in the mercury isotopes. Experimental results are reproduced by mean-field calculations where the ground or isomeric states were identified by the blocked quasiparticle configuration compatible with the observed spin, parity, and magnetic moment.

9.
J Environ Manage ; 293: 112951, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34098352

RESUMO

Olive oil production shapes the socio-economic and environmental life of many areas of the Mediterranean basin, especially southern Spain, the highest olive oil-producing region worldwide. Olive grove cultivation is tending to intensify from traditional low-density to intensive and high-density cropping systems, which might result in higher environmental impacts. The aim of this study is to estimate the environmental impacts, carbon (C) footprint and carbon balance of producing virgin origin olive oil in Spain from four traditional rainfed, four irrigated, and three intensive olive farms, including the processing phase. Environmental impacts of producing 1 kg of unpacked virgin olive oil at the farm and industrial phases were quantified with the Life Cycle Assessment (LCA) tool and a "cradle-to-gate" approach using data from surveys at these farms and 12 olive oil mills. On average, the farming phase accounted for 76.3% of the EIs. Therefore, to reduce the impact of the virgin olive oils production, most of the efforts should be made especially in the farming phase. Despite the high variability between seasons and between independent replicates of the same farming system, intensive farming had significant higher impacts on most environmental impact categories than traditional rainfed farming, mainly due to the application of nitrogen fertilizer, plant protection products and herbicides. In terms of climate change, the environmental impact of the functional unit is in the ranges of 1.80-2.41, 1.59-2.78 and 2.28-3.26 kg of CO2 eq. for traditional rainfed, irrigated and intensive, respectively. C footprint was negative and averaged -5.5, -4.3 and -2.7 kg CO2 eq. Olive groves are efficient atmospheric CO2 sinks mainly by fixing CO2 into permanent and non-permanent trees structures. The lower intensification of the traditional rainfed groves contributed more in mitigating the increase of atmospheric CO2. Finally, the C footprint and C balance are negative, especially in traditional irrigated and intensive farming. The application of organic sources of fertilizer and the implementation of temporary spontaneous cover crops, both technically and economically feasible, are sound strategies to achieve a positive carbon balance and reduce the impacts of olive cultivation.


Assuntos
Olea , Animais , Carbono , Pegada de Carbono , Estágios do Ciclo de Vida , Azeite de Oliva , Espanha
10.
Phys Rev Lett ; 122(19): 192502, 2019 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-31144969

RESUMO

The change in mean-square nuclear charge radii δ⟨r^{2}⟩ along the even-A tin isotopic chain ^{108-134}Sn has been investigated by means of collinear laser spectroscopy at ISOLDE/CERN using the atomic transitions 5p^{2} ^{1}S_{0}→5p6 s^{1}P_{1} and 5p^{2} ^{3}P_{0}→5p6s ^{3}P_{1}. With the determination of the charge radius of ^{134}Sn and corrected values for some of the neutron-rich isotopes, the evolution of the charge radii across the N=82 shell closure is established. A clear kink at the doubly magic ^{132}Sn is revealed, similar to what has been observed at N=82 in other isotopic chains with larger proton numbers, and at the N=126 shell closure in doubly magic ^{208}Pb. While most standard nuclear density functional calculations struggle with a consistent explanation of these discontinuities, we demonstrate that a recently developed Fayans energy density functional provides a coherent description of the kinks at both doubly magic nuclei, ^{132}Sn and ^{208}Pb, without sacrificing the overall performance. A multiple correlation analysis leads to the conclusion that both kinks are related to pairing and surface effects.

17.
Phys Rev Lett ; 116(18): 182502, 2016 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-27203317

RESUMO

Collinear laser spectroscopy is performed on the _{30}^{79}Zn_{49} isotope at ISOLDE-CERN. The existence of a long-lived isomer with a few hundred milliseconds half-life is confirmed, and the nuclear spins and moments of the ground and isomeric states in ^{79}Zn as well as the isomer shift are measured. From the observed hyperfine structures, spins I=9/2 and I=1/2 are firmly assigned to the ground and isomeric states. The magnetic moment µ (^{79}Zn)=-1.1866(10)µ_{N}, confirms the spin-parity 9/2^{+} with a νg_{9/2}^{-1} shell-model configuration, in excellent agreement with the prediction from large scale shell-model theories. The magnetic moment µ (^{79m}Zn)=-1.0180(12)µ_{N} supports a positive parity for the isomer, with a wave function dominated by a 2h-1p neutron excitation across the N=50 shell gap. The large isomer shift reveals an increase of the intruder isomer mean square charge radius with respect to that of the ground state, δ⟨r_{c}^{2}⟩^{79,79m}=+0.204(6) fm^{2}, providing first evidence of shape coexistence.

20.
Phys Rev Lett ; 115(13): 132501, 2015 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-26451548

RESUMO

New technical developments have led to a 2 orders of magnitude improvement of the resolution of the collinear resonance ionization spectroscopy (CRIS) experiment at ISOLDE, CERN, without sacrificing the high efficiency of the CRIS technique. Experimental linewidths of 20(1) MHz were obtained on radioactive beams of francium, allowing us for the first time to determine the electric quadrupole moment of the short lived [t_{1/2}=22.0(5) ms] ^{219}Fr Q_{s}=-1.21(2) eb, which would not have been possible without the advantages offered by the new method. This method relies on a continuous-wave laser and an external Pockels cell to produce narrow-band light pulses, required to reach the high resolution in two-step resonance ionization. Exotic nuclei produced at rates of a few hundred ions/s can now be studied with high resolution, allowing detailed studies of the anchor points for nuclear theories.

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