RESUMEN
The proton is one of the main building blocks of all visible matter in the Universe1. Among its intrinsic properties are its electric charge, mass and spin2. These properties emerge from the complex dynamics of its fundamental constituents-quarks and gluons-described by the theory of quantum chromodynamics3-5. The electric charge and spin of protons, which are shared among the quarks, have been investigated previously using electron scattering2. An example is the highly precise measurement of the electric charge radius of the proton6. By contrast, little is known about the inner mass density of the proton, which is dominated by the energy carried by gluons. Gluons are hard to access using electron scattering because they do not carry an electromagnetic charge. Here we investigated the gravitational density of gluons using a small colour dipole, through the threshold photoproduction of the J/ψ particle. We determined the gluonic gravitational form factors of the proton7,8 from our measurement. We used a variety of models9-11 and determined, in all cases, a mass radius that is notably smaller than the electric charge radius. In some, but not all cases, depending on the model, the determined radius agrees well with first-principle predictions from lattice quantum chromodynamics12. This work paves the way for a deeper understanding of the salient role of gluons in providing gravitational mass to visible matter.
RESUMEN
The visible world is founded on the proton, the only composite building block of matter that is stable in nature. Consequently, understanding the formation of matter relies on explaining the dynamics and the properties of the proton's bound state. A fundamental property of the proton involves the response of the system to an external electromagnetic field. It is characterized by the electromagnetic polarizabilities1 that describe how easily the charge and magnetization distributions inside the system are distorted by the electromagnetic field. Moreover, the generalized polarizabilities2 map out the resulting deformation of the densities in a proton subject to an electromagnetic field. They disclose essential information about the underlying system dynamics and provide a key for decoding the proton structure in terms of the theory of the strong interaction that binds its elementary quark and gluon constituents. Of particular interest is a puzzle in the electric generalized polarizability of the proton that remains unresolved for two decades2. Here we report measurements of the proton's electromagnetic generalized polarizabilities at low four-momentum transfer squared. We show evidence of an anomaly to the behaviour of the proton's electric generalized polarizability that contradicts the predictions of nuclear theory and derive its signature in the spatial distribution of the induced polarization in the proton. The reported measurements suggest the presence of a new, not-yet-understood dynamical mechanism in the proton and present notable challenges to the nuclear theory.
RESUMEN
In order to shorten the prognostically relevant waiting time until diagnosis and initiation of appropriate treatment in inflammatory rheumatic diseases, rheumatological centers in many regions across Germany have established and continuously developed specific early care concepts. Evaluated models from Altötting·Burghausen, Berlin Buch, Düsseldorf and Heidelberg and their developmental stages as a response to internal and external challenges are presented in this overview. The transparent publication of the developmental steps and the exchange of experiences aim at promoting new early care concepts in other regions and continuing the joint dialogue for improvement of the early detection and quality of care of inflammatory rheumatic diseases in Germany.
Asunto(s)
Enfermedades Reumáticas , Berlin , Diagnóstico Precoz , Alemania , Humanos , Enfermedades Reumáticas/diagnóstico , Enfermedades Reumáticas/terapia , Ciudad de RomaRESUMEN
AIM: To review current evidence of nurses' involvement in end-of-life discussions with incurable cancer patients and their family caregivers. DESIGN: We conducted a systematic integrative review in accordance with PRISMA guidelines: PROSPERO, registration number: CRD42020186204. DATA SOURCES: CINAHL, Medline, PsycInfo, Embase. We searched for primary research between 2010 and 2020. RESULTS: Of 3,271 references, we found 15 eligible articles: qualitative (n = 12) and quantitative (n = 3). The studies focused on oncology nurses' perspective of involvement in end-of-life discussions. The data analysis resulted in four overall themes: (1) Nursing roles; the advocating, supporting, and reframing roles, and an undefined task, for example in medical consultations, (2) Trust building, (3) Nurse competences, and (4) Medical issues. SIGNIFICANCE OF RESULTS: The nurses have several roles in end-of-life discussions, but insufficient competencies to be involved in that kind of discussions, for example to involve and communicate with families. The findings implicate an educational need among the nurses. However, it also points toward an organizational change in the outpatient clinics, for example that end-of-life discussions follow a more structured approach, are offered in a scheduled manner, and that nurses invite the family caregivers to attend.
Asunto(s)
Neoplasias , Enfermeras y Enfermeros , Cuidadores , Muerte , Humanos , Neoplasias/complicacionesRESUMEN
PURPOSE: Previous literature has reported contradicting results regarding the relationship between tumor volume changes during radiotherapy treatment for non-small cell lung cancer (NSCLC) patients and locoregional recurrence-free rate or overall survival. The aim of this study is to validate the results from a previous study by using a different volume extraction procedure and evaluating an external validation dataset. METHODS: For two datasets of 94 and 141 NSCLC patients, gross tumor volumes were determined manually to investigate the relationship between tumor volume regression and locoregional control using Kaplan-Meier curves. For both datasets, different subgroups of patients based on histology and chemotherapy regimens were also investigated. For the first dataset (nâ¯= 94), automatically determined tumor volumes were available from a previously published study to further compare their correlation with updated clinical data. RESULTS: A total of 70 out of 94 patients were classified into the same group as in the previous publication, splitting the dataset based on median tumor regression calculated by the two volume extraction methods. Non-adenocarcinoma patients receiving concurrent chemotherapy with large tumor regression show reduced locoregional recurrence-free rates in both datasets (pâ¯< 0.05 in dataset 2). For dataset 2, the opposite behavior is observed for patients not receiving chemotherapy, which was significant for overall survival (pâ¯= 0.01) but non-significant for locoregional recurrence-free rate (pâ¯= 0.13). CONCLUSION: The tumor regression pattern observed during radiotherapy is not only influenced by irradiation but depends largely on the delivered chemotherapy schedule, so it follows that the relationship between patient outcome and the degree of tumor regression is also largely determined by the chemotherapy schedule. This analysis shows that the relationship between tumor regression and outcome is complex, and indicates factors that could explain previously reported contradicting findings. This, in turn, will help guide future studies to fully understand the relationship between tumor regression and outcome.
Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/diagnóstico por imagen , Carcinoma de Pulmón de Células no Pequeñas/radioterapia , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/radioterapia , Carga Tumoral/efectos de la radiación , Adulto , Anciano , Anciano de 80 o más Años , Tomografía Computarizada de Haz Cónico , Femenino , Humanos , Estimación de Kaplan-Meier , Pulmón/diagnóstico por imagen , Pulmón/efectos de la radiación , Masculino , Persona de Mediana EdadRESUMEN
We report the first measurement of the (e,e^{'}p) three-body breakup reaction cross sections in helium-3 (^{3}He) and tritium (^{3}H) at large momentum transfer [⟨Q^{2}⟩≈1.9 (GeV/c)^{2}] and x_{B}>1 kinematics, where the cross section should be sensitive to quasielastic (QE) scattering from single nucleons. The data cover missing momenta 40≤p_{miss}≤500 MeV/c that, in the QE limit with no rescattering, equals the initial momentum of the probed nucleon. The measured cross sections are compared with state-of-the-art ab initio calculations. Overall good agreement, within ±20%, is observed between data and calculations for the full p_{miss} range for ^{3}H and for 100≤p_{miss}≤350 MeV/c for ^{3}He. Including the effects of rescattering of the outgoing nucleon improves agreement with the data at p_{miss}>250 MeV/c and suggests contributions from charge-exchange (SCX) rescattering. The isoscalar sum of ^{3}He plus ^{3}H, which is largely insensitive to SCX, is described by calculations to within the accuracy of the data over the entire p_{miss} range. This validates current models of the ground state of the three-nucleon system up to very high initial nucleon momenta of 500 MeV/c.
RESUMEN
BACKGROUND: Little information on the natural history of patients with localized NSCLC is available since many of the studies covering the subject lack information on pathological confirmation, staging procedures and comorbidity. No randomized studies have compared SBRT with no treatment for patients with localized NSCLC. The purpose of this study was to evaluate whether SBRT has influence on overall survival for patients with localized NSCLC and investigate the effect of baseline ventilatory lung function on overall survival. MATERIAL AND METHODS: From 2007 to 2013, 136 patients treated with SBRT at Odense University Hospital were prospectively recorded. The thoracic SBRT consisted of three fractions of 15-22 Gy delivered in 9 days. For comparison, a national group of 73 untreated patients in the same time period was extracted from the Danish Lung Cancer Registry. All patients had histologically/cytologically proven NSCLC T1-2N0M0 with a tumour diameter ≤5 cm. RESULTS: The 5-year relative survival was 44% versus 7% for the SBRT and untreated groups, respectively. In a propensity score matched comparison the median overall survival was 47 months versus 11 months for the SBRT and untreated groups, respectively (p < .05). On multivariate analysis, SBRT was significantly associated with improved prognosis while ECOG performance status 2+ and tumour diameter ≥3 cm significantly predicted poorer prognosis. Severe to very severe reduction of forced expiratory volume in one second (FEV1) did not predict poorer survival for the SBRT treated patients with localized NSCLC. CONCLUSIONS: SBRT offers more favourable survival than no treatment for patients with localized NSCLC. Performance status of 0-1, tumour diameter less than 3 cm and SBRT predicted improved survival. SBRT should not be withheld for patients with localized NSCLC based on poor ventilatory lung function.
Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/radioterapia , Neoplasias Pulmonares/radioterapia , Radiocirugia/métodos , Anciano , Anciano de 80 o más Años , Carcinoma de Pulmón de Células no Pequeñas/mortalidad , Carcinoma de Pulmón de Células no Pequeñas/patología , Femenino , Humanos , Estimación de Kaplan-Meier , Neoplasias Pulmonares/mortalidad , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Sistema de Registros , Resultado del TratamientoRESUMEN
We report the first longitudinal-transverse separation of the deeply virtual exclusive π^{0} electroproduction cross section off the neutron and coherent deuteron. The corresponding four structure functions dσ_{L}/dt, dσ_{T}/dt, dσ_{LT}/dt, and dσ_{TT}/dt are extracted as a function of the momentum transfer to the recoil system at Q^{2}=1.75 GeV^{2} and x_{B}=0.36. The edâedπ^{0} cross sections are found compatible with the small values expected from theoretical models. The enâenπ^{0} cross sections show a dominance from the response to transversely polarized photons, and are in good agreement with calculations based on the transversity generalized parton distributions of the nucleon. By combining these results with previous measurements of π^{0} electroproduction off the proton, we present a flavor decomposition of the u and d quark contributions to the cross section.
RESUMEN
We present deeply virtual π^{0} electroproduction cross-section measurements at x_{B}=0.36 and three different Q^{2} values ranging from 1.5 to 2 GeV^{2}, obtained from Jefferson Lab Hall A experiment E07-007. The Rosenbluth technique is used to separate the longitudinal and transverse responses. Results demonstrate that the cross section is dominated by its transverse component and, thus, is far from the asymptotic limit predicted by perturbative quantum chromodynamics. Nonetheless, an indication of a nonzero longitudinal contribution is provided by the measured interference term σ_{LT}. Results are compared with several models based on the leading-twist approach of generalized parton distributions (GPDs). In particular, a fair agreement is obtained with models in which the scattering amplitude includes convolution terms of chiral-odd (transversity) GPDs of the nucleon with the twist-3 pion distribution amplitude. This experiment, together with previous extensive unseparated measurements, provides strong support to the exciting idea that transversity GPDs can be accessed via neutral pion electroproduction in the high-Q^{2} regime.
RESUMEN
Single-phase, ligand-free Cu2ZnSnS4 (CZTS) nanoparticles that can be dispersed in polar solvents are desirable for thin film solar cell fabrication, since water can be used as the solvent for the nanoparticle ink. In this work, ligand-free nanoparticles were synthesized using a simple hot injection method and the precursor concentration in the reaction medium was tuned to control the final product. The as-synthesized nanoparticles were characterized using various techniques, and were found to have a near-stoichiometric composition and a phase-pure kesterite crystal structure. No secondary phases were detected with Raman spectroscopy or scanning transmission electron microscopy energy dispersive x-ray spectroscopy. Furthermore, high resolution transmission electron microscopy showed large-sized nanoparticles with an average diameter of 23 nm ± 11 nm. This approach avoids all organic materials and toxic solvents that otherwise could hinder grain growth and limit the deposition techniques. In addition the synthesis route presented here results in nanoparticles of a large size compared to other ligand-free CZTS nanoparticles, due to the high boiling point of the solvents selected. Large particle size in CZTS nanoparticle solar cells may lead to a promising device performance. The results obtained demonstrate the suitability of the synthesized nanoparticles for application in low cost thin film solar cells.
RESUMEN
We report the first measurement of the target single-spin asymmetry, A(y), in quasielastic scattering from the inclusive reaction (3)He(↑)(e,e') on a (3)He gas target polarized normal to the lepton scattering plane. Assuming time-reversal invariance, this asymmetry is strictly zero for one-photon exchange. A nonzero A(y) can arise from the interference between the one- and two-photon exchange processes which is sensitive to the details of the substructure of the nucleon. An experiment recently completed at Jefferson Lab yielded asymmetries with high statistical precision at Q(2)=0.13, 0.46, and 0.97 GeV(2). These measurements demonstrate, for the first time, that the (3)He asymmetry is clearly nonzero and negative at the 4σ-9σ level. Using measured proton-to-(3)He cross-section ratios and the effective polarization approximation, neutron asymmetries of -(1-3)% were obtained. The neutron asymmetry at high Q(2) is related to moments of the generalized parton distributions (GPDs). Our measured neutron asymmetry at Q(2)=0.97 GeV(2) agrees well with a prediction based on two-photon exchange using a GPD model and thus provides a new, independent constraint on these distributions.
RESUMEN
Double-spin asymmetries and absolute cross sections were measured at large Bjorken x (0.25≤x≤0.90), in both the deep-inelastic and resonance regions, by scattering longitudinally polarized electrons at beam energies of 4.7 and 5.9 GeV from a transversely and longitudinally polarized (3)He target. In this dedicated experiment, the spin structure function g(2)((3)He) was determined with precision at large x, and the neutron twist-3 matrix element d(2)(n) was measured at ⟨Q(2)⟩ of 3.21 and 4.32 GeV(2)/c(2), with an absolute precision of about 10(-5). Our results are found to be in agreement with lattice QCD calculations and resolve the disagreement found with previous data at ⟨Q(2)⟩=5 GeV(2)/c(2). Combining d(2)(n) and a newly extracted twist-4 matrix element f(2)(n), the average neutron color electric and magnetic forces were extracted and found to be of opposite sign and about 30 MeV/fm in magnitude.
RESUMEN
We report the first measurement of the target-normal single-spin asymmetry in deep-inelastic scattering from the inclusive reaction 3)He(↑)(e,e')X on a polarized (3)He gas target. Assuming time-reversal invariance, this asymmetry is strictly zero in the Born approximation but can be nonzero if two-photon-exchange contributions are included. The experiment, conducted at Jefferson Lab using a 5.89 GeV electron beam, covers a range of 1.7
RESUMEN
We present a precise measurement of double-polarization asymmetries in the ^{3}He[over â](e[over â],e^{'}d) reaction. This particular process is a uniquely sensitive probe of hadron dynamics in ^{3}He and the structure of the underlying electromagnetic currents. The measurements have been performed in and around quasielastic kinematics at Q^{2}=0.25(GeV/c)^{2} for missing momenta up to 270 MeV/c. The asymmetries are in fair agreement with the state-of-the-art calculations in terms of their functional dependencies on p_{m} and ω, but are systematically offset. Beyond the region of the quasielastic peak, the discrepancies become even more pronounced. Thus, our measurements have been able to reveal deficiencies in the most sophisticated calculations of the three-body nuclear system, and indicate that further refinement in the treatment of their two-and/or three-body dynamics is required.
Asunto(s)
Neoplasias Encefálicas/prevención & control , Irradiación Craneana/efectos adversos , Hipocampo/efectos de la radiación , Neoplasias Pulmonares/patología , Tratamientos Conservadores del Órgano/efectos adversos , Órganos en Riesgo/efectos de la radiación , Neoplasias Encefálicas/epidemiología , Neoplasias Encefálicas/secundario , Cognición/fisiología , Cognición/efectos de la radiación , Irradiación Craneana/métodos , Relación Dosis-Respuesta en la Radiación , Estudios de Seguimiento , Hipocampo/diagnóstico por imagen , Hipocampo/fisiología , Humanos , Neoplasias Pulmonares/terapia , Imagen por Resonancia Magnética , Trastornos Neurocognitivos/etiología , Trastornos Neurocognitivos/prevención & control , Tratamientos Conservadores del Órgano/métodos , Órganos en Riesgo/fisiología , Traumatismos por Radiación/etiología , Traumatismos por Radiación/prevención & control , Dosificación Radioterapéutica , Planificación de la Radioterapia Asistida por Computador , Resultado del TratamientoRESUMEN
AIMS: In patients with locally advanced non-small cell lung cancer (LA-NSCLC), curative-intent radiotherapy (RT) or chemoradiotherapy (CRT) is associated with considerable toxicity, and approximately half of the patients die within two years. A better understanding of early mortality is needed to improve patient selection and guide supportive interventions. In this population-based, nationwide cohort study, we investigated the incidence, temporal distribution, and risk factors of early mortality. MATERIALS AND METHODS: Patients with stage II-III NSCLC treated with curative-intent RT/CRT in Denmark from 2010-2017 were included. Patients treated with preoperative or postoperative RT/CRT or stereotactic body radiation therapy were excluded. Early mortality was defined as all-cause death within 180 days from RT/CRT initiation. Multiple logistic regression was used to assess the impact of clinical and demographic variables. RESULTS: We included 1742 patients. The early mortality rate was 10%. The temporal distribution of deaths was uniform across the first year following RT/CRT, indicating the absence of a high-risk period. In multivariable analysis, increasing age and performance status, male sex, and unspecified histology (NSCLC not otherwise specified) were associated with an increased risk. By contrast, the Charlson Comorbidity Index (CCI), TNM stage, and treatment period did not significantly alter the risk of early mortality. Overall survival rates improved throughout the inclusion period but early mortality rates did not. CONCLUSION: No high-risk period for early mortality could be identified. Early mortality was not associated with CCI and other tools should be explored to quantify comorbidity for risk stratification in this setting.
RESUMEN
BACKGROUND: The objective of this study is the effectiveness of multidisciplinary rehabilitation on treatment-related adverse effects after completed radiotherapy in patients with prostate cancer (PCa). METHODS: In a single-centre oncology unit in Odense, Denmark, 161 PCa patients treated with radiotherapy and androgen deprivation therapy were randomly assigned to either a programme of two nursing counselling sessions and two instructive sessions with a physical therapist (n=79) or to usual care (n=82). Primary outcome was Expanded Prostate Cancer Index Composite (EPIC-26) urinary irritative sum-score. Before radiotherapy, pre-intervention 4 weeks after radiotherapy, and after a 20-week intervention, measurements included self-reported disease-specific quality of life (QoL; EPIC-26, including urinary, bowel, sexual, and hormonal symptoms), general QoL (Short-form-12, SF-12), pelvic floor muscle strength (Modified Oxford Scale), and pelvic floor electromyography. Intension-to-treat analyses were made with adjusted linear regression. RESULTS: The intervention improved, as compared with controls, urinary irritative sum-score 5.8 point (Cohen's d=0.40; P=0.011), urinary sum-score (d=0.34; P=0.023), hormonal sum-score (d=0.19; P=0.018), and the SF-12 Physical Component Summary, d=0.35; P=0.002. Patients with more severe impairment gained most. Pelvic floor muscle strength measured by electromyography declined in both groups, P=0.0001. CONCLUSION: Multidisciplinary rehabilitation in irradiated PCa patients improved urinary and hormonal symptoms, and SF-12 physical QoL.
Asunto(s)
Neoplasias de la Próstata/rehabilitación , Neoplasias de la Próstata/terapia , Anciano , Antagonistas de Andrógenos/uso terapéutico , Consejo , Humanos , Masculino , Neoplasias de la Próstata/fisiopatología , Neoplasias de la Próstata/psicología , Calidad de Vida , Radioterapia , Resultado del TratamientoRESUMEN
We report on parity-violating asymmetries in the nucleon resonance region measured using inclusive inelastic scattering of 5-6 GeV longitudinally polarized electrons off an unpolarized deuterium target. These results are the first parity-violating asymmetry data in the resonance region beyond the Δ(1232). They provide a verification of quark-hadron duality-the equivalence of the quark- and hadron-based pictures of the nucleon-at the (10-15)% level in this electroweak observable, which is dominated by contributions from the nucleon electroweak γZ interference structure functions. In addition, the results provide constraints on nucleon resonance models relevant for calculating background corrections to elastic parity-violating electron scattering measurements.
RESUMEN
This study explores prostate cancer patients' experiences of rehabilitation after radiotherapy with androgen deprivation therapy (ADT). Patients who had completed a multidisciplinary rehabilitation programme with psychosocial support and physiotherapy were interviewed in two focus groups: Group 1 consisted of six men who came to the rehabilitation with their spouses, and Group 2 of seven men who came alone. Meaning condensation was used to analyse the interviews. Radiotherapy was described as full-time work. Adverse effects due to ADT influencing masculinity and identity were emphasised. The men embraced life with a particular sense of humour. Whether rehabilitation was experienced as useful depended on the health professionals' approach, and on the patients' motivation and effort to contribute to health promotion, and to convert experiences into coping strategies. The supportive role of the spouse was emphasised by several, but some men preferred to handle the process alone. In conclusion, men undergoing ADT should be carefully informed of the consequences. Spousal involvement in rehabilitation must be decided by the patient. The focus group interviews themselves had a positive impact on the men's understanding of their rehabilitation processes. The specific male approach and differences between the needs of female and male cancer patients are important to understand when planning rehabilitation.
Asunto(s)
Antagonistas de Andrógenos/efectos adversos , Neoplasias de la Próstata/psicología , Radioterapia/efectos adversos , Adaptación Psicológica , Anciano , Antagonistas de Andrógenos/uso terapéutico , Grupos Focales , Humanos , Masculino , Masculinidad , Neoplasias de la Próstata/rehabilitación , Neoplasias de la Próstata/terapia , Factores Sexuales , Apoyo Social , Esposos , Encuestas y CuestionariosRESUMEN
Modelling contagious diseases needs to include a mechanistic knowledge about contacts between hosts and pathogens as specific as possible, e.g., by incorporating in the model information about social networks through which the disease spreads. The unknown part concerning the contact mechanism can be modelled using a stochastic approach. For that purpose, we revisit SIR models by introducing first a microscopic stochastic version of the contacts between individuals of different populations (namely Susceptible, Infective and Recovering), then by adding a random perturbation in the vicinity of the endemic fixed point of the SIR model and eventually by introducing the definition of various types of random social networks. We propose as example of application to contagious diseases the HIV, and we show that a micro-simulation of individual based modelling (IBM) type can reproduce the current stable incidence of the HIV epidemic in a population of HIV-positive men having sex with men (MSM).