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In this paper, we study the shape and dynamics of helical coherent structures found in the flow field of an annular swirling jet undergoing vortex breakdown. The flow field is studied by means of time-resolved tomographic particle image velocimetry measurements. The obtained flow fields are analysed using both classic and spectral proper orthogonal decomposition. Despite the simple geometrical set-up of the annular jet, the flow field is very complex. Two distinct large-scale helical flow structures are identified: a single and a double helix, both co-rotating with the swirl direction, and it is revealed that these structures are not higher harmonics of each other. The structures have a relatively low energy content which makes it hard to separate them from other dynamics of the flow field, notably turbulent motions. Because of this, classic proper orthogonal decomposition fails to identify both structures properly. Spectral proper orthogonal decomposition, on the other hand, allows them to be identified accurately when the filter size is set at around eight times the precession period. The precession frequencies of the single and double helices correspond to Strouhal numbers of 0.273 and
, respectively. A global stability analysis of the mean flow field shows that these structures correspond to two separate global modes. The precessing frequencies obtained by the stability analysis and the related spatial structures match very well with the experimental observations. The current work extends our knowledge on turbulent vortex breakdown and on mean field global stability theory in general. It leads to the following conclusions. Firstly, single- and double-helix vortex breakdown are both manifestations of global modes. Previous studies have shown that both
modes can coexist in swirling jets. However, the
mode has been identified as a second harmonic of the first mode, while this study identifies both as two independent global modes. Secondly, this work shows that the simultaneous occurrence of multiple helical global modes is possible within a turbulent flow and their shapes and frequencies are very well predicted by mean field stability analysis. The latter finding is of general interest as it applies to a wide class of fluid problems dominated by multiple oscillatory structures.
Free-ranging grey wolves (Canis lupus), which are presently recolonizing Italy, can be parasitized by a diversity of helminths, but have rarely been subject to studies of their parasites. Therefore, this study aims to determine the prevalence of gastrointestinal helminths of road-killed grey wolves from the Piedmont region of Italy. Forty-two wolves were collected and examined for the presence of helminths. We recorded 12 helminth species: nine Nematoda and three Cestoda. The nematodes were: Ancylostoma caninum (7.1%), Capillaria sp. (2.4%), Molineus sp. (2.4%), Pterygodermatites affinis (11.9%), Physaloptera sibirica (9.5%), Toxocara canis (9.5%), Toxascaris leonina (2.4%) and Uncinaria stenocephala (26.2%); the cestodes were: Dipylidium caninum (4.8%), Mesocestoides sp. (4.8%) and Taenia multiceps (76.2%). Physaloptera sibirica had the highest mean intensity and T. multiceps had the highest prevalence. Based on age and sex, no differences in the intensity or prevalence of helminth species were found among the hosts. Molineus sp. was recorded for the first time in wolves from the Palearctic region; P. affinis and P. sibirica are respectively reported for the first time in wolves from Europe and Italy.
This is a copy of the slides presented at the meeting but not formally written up for the volume.
Description: Semiconductor physics contains a rich body of theory and working designs. However, their material properties seem to be reaching their limits. Perovskite oxides on the other hand have abundant physical properties, but are still under active investigation. The advent of RHEED-monitoring of pulsed laser deposition allows for the fabrication of structures with single unit cell (4 Å) thick layers. In this way we may be able to fabricate quantum well structures for both applications and fundamental investigations. Superlattices of the Mott insulator LaTiO3 (LTO) and the band gap insulator SrTiO3 (STO) form such a structure. The superlattices are metallic, both as-grown and post-annealed . This has been attributed to the existence of metallic states at the interfaces between LTO and STO . At these interfaces the electron density is found to extend about 10 Å into the STO. However, theoretically, the required length scale for quantum confinement is of the order of 4 Å. A possible way to increase this confinement is to use a buffer material with a larger band gap than that of LTO (similar to semiconductor band gap engineering) and/or with a lower dielectric constant . LaAlO3 (LAO) is such a material (ΔELAO = 5.6 eV vs. ΔESTO = 3.2 eV, εLAO = 24 vs. εSTO = 300). Here we report on the growth of LTO/LAO superlattices on STO substrates. As-grown superlattices of LTO/LAO are metallic, while post-annealing turns them insulating. This may be explained from a disorder-order transition in a 2D Mott-Hubbard model . XPS and EELS measurements of the titanium valence show interesting differences for LTO layers close to and far away from the sample surface. The former, for thin LAO capping layers, show the presence of Ti4+ while the latter only have Ti3+. Hard XPS of samples with varying capping layer thickness shows an exponential dependence of the Ti3+ contents on a length scale of about 5 unit cells.  A. Ohtomo et al., Nature 419, 378-380 (2002).  S. Okamoto & A.J. Millis, Phys. Rev. B 70, 075101 (2004).  D. Heidarian & N. Trivedi, Phys. Rev. Lett. 93, 126401 (2004).
We aimed to examine the association between pain, stiffness and fatigue in newly diagnosed polymyalgia rheumatica (PMR) patients using baseline data from a prospective cohort study. Fatigue is a known, but often ignored symptom of PMR. Newly diagnosed PMR patients were recruited from general practice and mailed a baseline questionnaire. This included a numerical rating scale for pain and stiffness severity, manikins identifying locations of pain and stiffness and the FACIT-Fatigue questionnaire. A total of 652 PMR patients responded (88.5%). The mean age of responders was 72.6 years (SD 9.0) and the majority were female (62.0%). Manikin data demonstrated that bilateral shoulder and hip pain and stiffness were common. The mean fatigue score (FACIT) was 33.9 (SD 12.4). Adjusted regression analysis demonstrated that a higher number of pain sites (23–44 sites) and higher pain and stiffness severity were associated with greater levels of fatigue. In newly diagnosed PMR patients, fatigue was associated with PMR symptom severity.
The current study describes the results obtained from clinical examination of over 4700 suckling piglets from 19 individual herds in Germany. In this cohort the prevalence of inflammation and necrosis in the tails, ears, claw coronary bands, heels and teats was determined using a pre-defined scoring system. Results show that already in the 1st days of life, piglets were affected by inflammation and necrosis of the heels (80%), claw coronary bands (50%) and tail base (20%). The praevalences of these alterations in piglets were influenced by genetics (P <0.001) and age, decreasing gradually in the 2nd week of life (P <0.001). Moreover, a correlation between tail length after tail docking and the prevalence of tail necrosis (P⩽0.04) was found. Tail and ear biting as a behavioural trait was not detected during this study. The early onset, appearance and multiple locations of clinical signs of inflammation and the positive correlation with the genetic background of the piglets may suggest an impairment of the innate immune system by infectious and non-infectious agents. This is in contrast to previously described behavioural abnormalities seen in fattening pigs. Considering the obvious reduction of animal welfare due to the described lesions, there is a need to create awareness among pig farmers and to understand the multifactorial causality involved in this inflammation and necrosis syndrome in piglets.
Compulsory admission can be experienced as devaluing and stigmatising by people with mental illness. Emotional reactions to involuntary hospitalisation and stigma-related stress may affect recovery, but longitudinal data are lacking. We, therefore, examined the impact of stigma-related emotional reactions and stigma stress on recovery over a 2-year period.
Shame and self-contempt as emotional reactions to involuntary hospitalisation, stigma stress, self-stigma and empowerment, as well as recovery were assessed among 186 individuals with serious mental illness and a history of recent involuntary hospitalisation.
More shame, self-contempt and stigma stress at baseline were correlated with increased self-stigma and reduced empowerment after 1 year. More stigma stress at baseline was associated with poor recovery after 2 years. In a longitudinal path analysis more stigma stress at baseline predicted poorer recovery after 2 years, mediated by decreased empowerment after 1 year, controlling for age, gender, symptoms and recovery at baseline.
Stigma stress may have a lasting detrimental effect on recovery among people with mental illness and a history of involuntary hospitalisation. Anti-stigma interventions that reduce stigma stress and programs that enhance empowerment could improve recovery. Future research should test the effect of such interventions on recovery.
This paper provides a contextual summary of a diachronic analysis of ceramic vessels and hunter-gatherer societies from the final Pleistocene to the later Holocene in a remote corner of the Vitim Basin in Eastern Siberia. An integrated programme of ceramic analysis, raw materials survey, and archaeological investigation is drawn into new models of group mobility and social behaviour. The results challenge widespread assumptions about the relationship between ceramics, sedentarisation, and social complexity. Evidence of these transformations, though potentially identifiable in the archaeological record, could not be associated with the adoption of pottery.
Recent evidence shows that the serotonin 2A receptor (5-hydroxytryptamine2A receptor, 5-HT2AR) is critically involved in the formation of visual hallucinations and cognitive impairments in lysergic acid diethylamide (LSD)-induced states and neuropsychiatric diseases. However, the interaction between 5-HT2AR activation, cognitive impairments and visual hallucinations is still poorly understood. This study explored the effect of 5-HT2AR activation on response inhibition neural networks in healthy subjects by using LSD and further tested whether brain activation during response inhibition under LSD exposure was related to LSD-induced visual hallucinations.
In a double-blind, randomized, placebo-controlled, cross-over study, LSD (100 µg) and placebo were administered to 18 healthy subjects. Response inhibition was assessed using a functional magnetic resonance imaging Go/No-Go task. LSD-induced visual hallucinations were measured using the 5 Dimensions of Altered States of Consciousness (5D-ASC) questionnaire.
Relative to placebo, LSD administration impaired inhibitory performance and reduced brain activation in the right middle temporal gyrus, superior/middle/inferior frontal gyrus and anterior cingulate cortex and in the left superior frontal and postcentral gyrus and cerebellum. Parahippocampal activation during response inhibition was differently related to inhibitory performance after placebo and LSD administration. Finally, activation in the left superior frontal gyrus under LSD exposure was negatively related to LSD-induced cognitive impairments and visual imagery.
Our findings show that 5-HT2AR activation by LSD leads to a hippocampal–prefrontal cortex-mediated breakdown of inhibitory processing, which might subsequently promote the formation of LSD-induced visual imageries. These findings help to better understand the neuropsychopharmacological mechanisms of visual hallucinations in LSD-induced states and neuropsychiatric disorders.
OSO absorption spectra may offer a clue to the distribution of intervening matter clouds at z = 0 … 3. We tackle 1) the question of the occurrence of metal absorption lines of different ionisation levels in the same redshift systems by investigating the radiation transport through an inhomogeneous temperature profile; 2) the clustering properties of the lines of the Lyα forest by a correlation analysis of 9 published high-resolution QSO-spectra with the result of a certain contribution of metal absorption lines as well as marginally significant positive correlation regions ξ ≈ 0.3.
Talcing into account vacuum polarization effects and a coherent massive scalar field we consider a singularity free cosmological model from which an intermediate inflationary stage follows quite naturally. According to the ideas of Tryon, Fomin, Zeldovich and others on the spontaneous creation of an universe by a quantum process the newly created universe must be closed. Its evolution starts from a finite initial value a of the order of the Planck length with a zero velocity ho = 0 (h - Hubble parameter). Therefore, in this moment an effective source term not fulfilling the strong energy condition must be dominant. It can originate fron a coherent massive scalar field (mass m) with zero kinetic energy and/or the vacuum polarization (considered here in the form of a modified gravitational Lagrangian with quadratic terms of the Ricci scalar). The corresponding general Lagrangian reads (c = h =1)
where ∝ is a negative coupling constant and Lmat is the Lagrangian of other possible existing matter. Both the massive scalar field and the vacuum polarization effects drive the universe to expand exponentially for a definite time interval depending on the initial radius a0 and the parameters m and ∝, during which all other matter being originally present is diluted. The following small oscillations superimposed on the dust-like power law behaviour of the scale factor cause an intensive particle production, and the universe heats up to a radiation dominated Friedmann universe. This process must terminate before baryogenesis. The matching of the different phases of the cosmological evolution and the requirement to fit the parameters of the observed universe lead to a definite parameter range for m and |∝| well below the Planck values. In consequence the present mass density must be equal to the critical one (Ω = 1) with high accuracy.
We consider two density perturbation modes with significantly different length scales λ and L (λ ≪ L) in a homogeneous Universe within Newtonian approximation. For the two modes the coupling terms in the corresponding Euler-Lagrange and Poisson equations are taken into account within lowest order of approximation. We assume that the λ - nods (high-frequency mode) is superimposed on the large-scale mode in such way that by an appropriate averaging procedure, the global behaviour is determined only by the single L-mode. Locally (Δ x ≈ λ ≪ L) the space dependence of the L-mode can be neglected in comparison with the λ -mode, but its time evolution remains important for the evolution of the λ -mode perturbation δ. We obtain for δ the equation:
where , b is the sound velocity with respect to the undisturbed homogeneous natter distribution, H is the Hubble parameter, .
To achieve their conservation goals individuals, communities and organizations need to acquire a diversity of skills, knowledge and information (i.e. capacity). Despite current efforts to build and maintain appropriate levels of conservation capacity, it has been recognized that there will need to be a significant scaling-up of these activities in sub-Saharan Africa. This is because of the rapid increase in the number and extent of environmental problems in the region. We present a range of socio-economic contexts relevant to four key areas of African conservation capacity building: protected area management, community engagement, effective leadership, and professional e-learning. Under these core themes, 39 specific recommendations are presented. These were derived from multi-stakeholder workshop discussions at an international conference held in Nairobi, Kenya, in 2015. At the meeting 185 delegates (practitioners, scientists, community groups and government agencies) represented 105 organizations from 24 African nations and eight non-African nations. The 39 recommendations constituted six broad types of suggested action: (1) the development of new methods, (2) the provision of capacity building resources (e.g. information or data), (3) the communication of ideas or examples of successful initiatives, (4) the implementation of new research or gap analyses, (5) the establishment of new structures within and between organizations, and (6) the development of new partnerships. A number of cross-cutting issues also emerged from the discussions: the need for a greater sense of urgency in developing capacity building activities; the need to develop novel capacity building methodologies; and the need to move away from one-size-fits-all approaches.