2,341 research outputs found
Gas gun shock experiments with single-pulse x-ray phase contrast imaging and diffraction at the Advanced Photon Source
The highly transient nature of shock loading and pronounced microstructure
effects on dynamic materials response call for {\it in situ}, temporally and
spatially resolved, x-ray-based diagnostics. Third-generation synchrotron x-ray
sources are advantageous for x-ray phase contrast imaging (PCI) and diffraction
under dynamic loading, due to their high photon energy, high photon fluxes,
high coherency, and high pulse repetition rates. The feasibility of bulk-scale
gas gun shock experiments with dynamic x-ray PCI and diffraction measurements
was investigated at the beamline 32ID-B of the Advanced Photon Source. The
x-ray beam characteristics, experimental setup, x-ray diagnostics, and static
and dynamic test results are described. We demonstrate ultrafast, multiframe,
single-pulse PCI measurements with unprecedented temporal (100 ps) and
spatial (2 m) resolutions for bulk-scale shock experiments, as well
as single-pulse dynamic Laue diffraction. The results not only substantiate the
potential of synchrotron-based experiments for addressing a variety of shock
physics problems, but also allow us to identify the technical challenges
related to image detection, x-ray source, and dynamic loading
Resonance shifts and spill-out effects in self-consistent hydrodynamic nanoplasmonics
The standard hydrodynamic Drude model with hard-wall boundary conditions can
give accurate quantitative predictions for the optical response of noble-metal
nanoparticles. However, it is less accurate for other metallic nanosystems,
where surface effects due to electron density spill-out in free space cannot be
neglected. Here we address the fundamental question whether the description of
surface effects in plasmonics necessarily requires a fully quantum-mechanical
approach, such as time-dependent density-functional theory (TD-DFT), that goes
beyond an effective Drude-type model. We present a more general formulation of
the hydrodynamic model for the inhomogeneous electron gas, which additionally
includes gradients of the electron density in the energy functional. In doing
so, we arrive at a Self-Consistent Hydrodynamic Model (SC-HDM), where spill-out
emerges naturally. We find a redshift for the optical response of Na nanowires,
and a blueshift for Ag nanowires, which are both in quantitative agreement with
experiments and more advanced quantum methods. The SC-HDM gives accurate
results with modest computational effort, and can be applied to arbitrary
nanoplasmonic systems of much larger sizes than accessible with TD-DFT methods.
Moreover, while the latter typically neglect retardation effects due to
time-varying magnetic fields, our SC-HDM takes retardation fully into account.Comment: 27 pages, including 4 figures. Supplemental Material is available
upon request to author
The Okun Misery Index in the European Union Countries from 2000 to 2009
The study is composed of four main parts and a summary. The first part, introduction, discusses various measures of the economic system's efficiency that are used in practice. Part two emphasises that the GDP per capita according to purchasing power parity still remains the most popular among those measures. Further, it presents the ranking of the European Union countries taking that measure into account, the research period being 1999-2009. Part three points out that it is also the level of poverty (misery) that determines the economic system's efficiency. That level can be measured by means of various indicators, among others, the so called HPI-2 index calculated by the UN. It will be the Okun misery index, however, computed as the sum of inflation and unemployment rates that will be presented as an alternative being of interest from the macroeconomic point of view. The ranking of the European Union member states according to that measure in the 2000-2004 and 2005-2009 periods will be provided in part four. The article will end in a summary containing synthetic conclusions drawn from earlier observations.Opracowanie składa się z czterech części zasadniczych i podsumowania. W punkcie pierwszym omówiono różnorodne mierniki sprawności systemu gospodarczego wykorzystywane w praktyce. W części drugiej podkreślono, iż nadal najpopularniejszym z nich jest PKB per capita według parytetu siły nabywczej. Zgodnie z tym miernikiem przedstawiono ranking państw Unii Europejskiej w latach 1999-2009. W punkcie trzecim podkreślono, że o sprawności systemu gospodarczego decyduje także poziom ubóstwa. Może być on mierzony różnymi wskaźnikami, m.in. tzw. indeksem HPI-2 obliczanym przez ONZ. Jako ciekawą z makroekonomicznego punktu widzenia alternatywę ukazano jednak miarę wskaźnika ubóstwa Okuna obliczanego poprzez zsumowanie stopy inflacji i stopy bezrobocia. Ranking państw Unii Europejskiej według tej miary w okresach 2000-2004 oraz 2005-2009 zaprezentowano w części czwartej. Całość zamknięto podsumowaniem, w którym zawarto syntetyczne wnioski z przeprowadzonych obserwacji
Towards exotic nuclei via binary reaction mechanism
Assuming a binary reaction mechanism, the yield of isotopes near the heaviest
neutron-deficit nucleus Sn is studied with a microscopic
transport model. The large influence of nuclear shell structure and isotope
composition of the colliding nuclei on the production of exotic nuclei is
demonstrated. It is shown that the reaction Fe+Cd seems to be
most favourable for producing primary exotic Sn isotopes which may survive if
the excitation energy in the entrance reaction channel is less than about 100
MeV. In the case of large differences in the charge (mass) numbers between
entrance and exit channels the light fragment yield is essentially fed from the
decay of excited primary heavier fragments. The existence of optimal energies
for the production of some oxygen isotopes in the binary mechanism is
demonstrated for the S+Au reaction.Comment: 17 pages, RevTex, 8 Postscript figures, submitted to Phys. Rev.
Meta-Inflammation and Metabolic Reprogramming of Macrophages in Diabetes and Obesity:The Importance of Metabolites
Diabetes mellitus type II and obesity are two important causes of death in modern society. They are characterized by low-grade chronic inflammation and metabolic dysfunction (meta-inflammation), which is observed in all tissues involved in energy homeostasis. A substantial body of evidence has established an important role for macrophages in these tissues during the development of diabetes mellitus type II and obesity. Macrophages can activate into specialized subsets by cues from their microenvironment to handle a variety of tasks. Many different subsets have been described and in diabetes/obesity literature two main classifications are widely used that are also defined by differential metabolic reprogramming taking place to fuel their main functions. Classically activated, pro-inflammatory macrophages (often referred to as M1) favor glycolysis, produce lactate instead of metabolizing pyruvate to acetyl-CoA, and have a tricarboxylic acid cycle that is interrupted at two points. Alternatively activated macrophages (often referred to as M2) mainly use beta-oxidation of fatty acids and oxidative phosphorylation to create energy-rich molecules such as ATP and are involved in tissue repair and downregulation of inflammation. Since diabetes type II and obesity are characterized by metabolic alterations at the organism level, these alterations may also induce changes in macrophage metabolism resulting in unique macrophage activation patterns in diabetes and obesity. This review describes the interactions between metabolic reprogramming of macrophages and conditions of metabolic dysfunction like diabetes and obesity. We also focus on different possibilities of measuring a range of metabolites intra-and extracellularly in a precise and comprehensive manner to better identify the subsets of polarized macrophages that are unique to diabetes and obesity. Advantages and disadvantages of the currently most widely used metabolite analysis approaches are highlighted. We further describe how their combined use may serve to provide a comprehensive overview of the metabolic changes that take place intracellularly during macrophage activation in conditions like diabetes and obesity
Assessing Readiness for Clinical Practice: Students’ Perspectives of their Veterinary Curriculum
Studies describing the effectiveness of a veterinary curriculum from the student perspective are currently sparse. The overall purpose of this investigation was to describe students’ perceived preparedness for clinical practice. Three focus group meetings with fourth year veterinary students were conducted. Data were open-coded and categorized to identify themes. Four main themes emerged: Challenging communications, Un/appreciating curricular experiences, Documenting demands impede case involvement, and Hungering for timely, effective feedback. Overall students felt comfortable talking to clients about medicine but less comfortable discussing euthanasia or money; they appreciated the split clinical curriculum but questioned the value of the 1st/2nd year courses; they felt that paperwork on clinical rotations negatively impacted patient involvement; expressed the need for well-defined expectations regarding grading/assessment and autonomy on clinical rotations. Despite the reported issues, students expressed satisfaction with the split curriculum and readiness to enter their chosen field of study
Entorse de la cheville chez le jeune sportif [Ankle sprain in youth athlete]
Lateral ankle sprain is the most frequent musculoskeletal injury in the young athlete. Myths, dogma and common belief are regularly encountered when discussing this injury, for which the scientific literature does not prevail yet. In the youth, the growing skeleton further influences the diagnosis and therapeutic processes, as well as the healing potential. For the athlete, a fast recovery and return to sports without recurrence are a priority. In this specific context, an integrated management of the ankle sprain in the young athlete must be based on an adequate diagnosis, a sound knowledge of pediatrics pitfalls and peer-reviewed physiotherapy recommendations and consensus statements
Spin dynamic simulations of solid effect DNP: the role of the relaxation superoperator
Relaxation plays a crucial role in the spin dynamics of dynamic nuclear polarisation. We review here two different strategies that have recently been used to incorporate relaxation in models to predict the spin dynamics of solid effect dynamic nuclear polarisation. A detailed explanation is provided how the Lindblad-Kossakowski form of the master equation can be used to describe relaxation in a spin system. Fluctuations of the spin interactions with the environment as a cause of relaxation are discussed and it is demonstrated how the relaxation superoperator acting in Liouville space on the density operator can be derived in the Lindblad-Kossakowski form by averaging out non-secular terms in an appropriate interaction frame. Furthermore we provide a formalism for the derivation of the relaxation superoperator starting with a choice of a basis set in Hilbert space. We show that the differences in the prediction of the nuclear polarisation dynamics that are found for certain parameter choices arise from the use of different interaction frames in the two different strategies. In addition we provide a summary of different relaxation mechanism that need to be considered to obtain more realistic spin dynamic simulations of solid effect dynamic nuclear polarisation
Non-communicable disease prevention in Kosovo: quantitative and qualitative assessment of uptake and barriers of an intervention for healthier lifestyles in primary healthcare
BACKGROUND: Smoking, physical inactivity, low fruit and vegetable consumption, and obesity are common in Kosovo. Their prevention is a priority to relieve the health system of from costly non-communicable disease treatments. The Accessible Quality Healthcare project is implementing a primary healthcare intervention that entails nurse-guided motivational counselling to facilitate change in the domains of smoking, diet, alcohol consumption and physical inactivity for at-risk patients. This study quantitatively assesses the uptake of motivational counselling and the distribution of health behaviours and stages of health behaviour change of the participants according to the intervention, as well as qualitatively describes experiences and perceived benefits of motivational counselling. METHODS: Study participants (n = 907) were recruited consecutively in 2019 from patients visiting the Main Family Medical Centres in 12 municipalities participating in the Kosovo Non-Communicable Disease Cohort study as part of the Accessible Quality Healthcare project. For the quantitative study, we used baseline and first follow-up data on smoking status, physical inactivity, obesity, fruit and vegetable as well as alcohol consumption, uptake of counselling, and stages for behavioural change. For the qualitative study, in-depth interviews were conducted with a subset of 26 cohort participants who had undergone motivational counselling. RESULTS: Motivational counselling was obtained by only 22% of the eligible participants in the intervention municipalities. Unhealthy behaviours are high even in persons who underwent counselling (of whom 13% are smokers; 86% physically inactive; 93% with inadequate fruit and vegetable consumption; and 61% are obese); only the rate of smoking was lower in those who obtained counselling. Among smokers, over 80% were still in the pre-contemplation phase of behaviour change. More advanced stages of behaviour change were observed among the highly prevalent group of inactive persons and participants with poor dietary habits, among the 5 intervention municipalities. According to the qualitative study results, the participants who obtained motivational counselling were very satisfied with the services but requested additional services such as group physical activity sessions and specialized services for smoking cessation. CONCLUSIONS: More tailored and additional primary health care approaches in accordance with patients' views need to be considered for the motivational counselling intervention to reach patients and efficiently facilitate lifestyle behaviour change
Strengthening primary healthcare in Kosovo requires tailoring primary, secondary and tertiary prevention interventions and consideration of mental health
Objectives: Kosovo has the lowest life expectancy in the Balkans. Primary healthcare (PHC) plays an essential role in non-communicable disease (NCD) prevention. We described primary, secondary and tertiary prevention indicators in Kosovo and assessed their association with depressive symptoms. Methods: PHC users (n = 977) from the Kosovo NCD cohort baseline study were included. Depressive symptoms were assessed using the Depressive Anxiety Stress Scale-21. Cross-sectional associations between depressive symptoms and prevention indicators were quantified with mixed logistic regression models. Results: Poor nutrition (85%), physical inactivity (70%), obesity (53%), and smoking (21%) were common NCD risk factors. Many cases of hypertension (19%), diabetes (16%) and Chronic Obstructive Pulmonary Disease (COPD) (45%) remained undetected by a PHC professional. Uncontrolled hypertension (28%), diabetes (79%), and COPD (76%) were also common. Depressive symptoms were positively associated with physical inactivity (OR 1.02; 95% CI 1.00-1.05 per 1-point increase in DASS-21) and undetected COPD (OR 1.07; 95% CI 1.00-1.15), but inversely with undetected diabetes (OR 0.95; 95% CI 0.91-1.00). Conclusions: Continued attention and tailored modifications to primary, secondary and tertiary prevention in Kosovo are needed to narrow the Balkan health gap
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