574 research outputs found
Bipartite representations and many-body entanglement of pure states of indistinguishable particles
We analyze a general bipartite-like representation of arbitrary pure states
of -indistinguishable particles, valid for both bosons and fermions, based
on - and -particle states. It leads to exact Schmidt-like
expansions of the state for any and is directly related to the
isospectral reduced - and -body density matrices and
. The formalism also allows for reduced yet still exact
Schmidt-like decompositions associated with blocks of these densities, in
systems having a fixed fraction of the particles in some single particle
subspace. Monotonicity of the ensuing -body entanglement under a certain set
of quantum operations is also discussed. Illustrative examples in fermionic and
bosonic systems with pairing correlations are provided, which show that in the
presence of dominant eigenvalues in , approximations based on a few
terms of the pertinent Schmidt expansion can provide a reliable description of
the state. The associated one- and two-body entanglement spectrum and entropies
are also analyzed.Comment: 17 pages, 5 figure
Preimplantation biopsy predicts delayed graft function, glomerular filtration rate and long-term graft survival of transplanted kidneys
Background
The predictive value of preimplantation biopsies for long-term graft function is often limited by conflicting results. The aim of this study was to evaluate the influence of time-zero graft biopsy histological scores on early and late graft function, graft survival and patient survival, at different time points.
Methods
We retrospectively analyzed 284 preimplantation biopsies at a single center, in a cohort of recipients with grafts from live and deceased donors (standard and nonstandard), and their impact in posttransplant renal function after a mean follow-up of 7 years (range 1â16). Implantation biopsy score (IBS), a combination score derived from 4 histopathological aspects, was determined from each sample. The correlation with incidence of delayed graft function (DGF), creatinine clearance (1st, 3rd and 5th posttransplant year) and graft and patient survival at 1 and 5 years were evaluated.
Results
Preimplantation biopsies provided somewhat of a prognostic index of early function and outcome of the transplanted kidney in the short and long term. In the immediate posttransplantation period, the degree of arteriolosclerosis and interstitial fibrosis correlated better with the presence of DGF. IBS values between 4 and 6 were predictive of worst renal function at 1st and 3rd years posttransplant and 5-year graft survival. The most important histological finding, in effectively transplanted grafts, was the grade of interstitial fibrosis. Patient survival was not influenced by IBS.
Conclusions
Higher preimplantation biopsy scores predicted an increased risk of early graft losses, especially primary nonfunction. Graft survival (at 1st and 5th years after transplant) but not patient survival was predicted by IBS
Computational modelling of emboli travel trajectories in cerebral arteries: Influence of microembolic particle size and density
This article has been made available through the Brunel Open Access Publishing Fund.Ischaemic stroke is responsible for up to 80 % of stroke cases. Prevention of the reoccurrence of ischaemic attack or stroke for patients who survived the first symptoms is the major treatment target. Accurate diagnosis of the emboli source for a specific infarction lesion is very important for a better treatment for the patient. However, due to the complex blood flow patterns in the cerebral arterial network, little is known so far of the embolic particle flow trajectory and its behaviour in such a complex flow field. The present study aims to study the trajectories of embolic particles released from carotid arteries and basilar artery in a cerebral arterial network and the influence of particle size, mass and release location to the particle distributions, by computational modelling. The cerebral arterial network model, which includes major arteries in the circle of Willis and several generations of branches from them, was generated from MRI images. Particles with diameters of 200, 500 and 800 Ό m and densities of 800, 1,030 and 1,300 kg/m 3 were released in the vessel's central and near-wall regions. A fully coupled scheme of particle and blood flow in a computational fluid dynamics software ANASYS CFX 13 was used in the simulations. The results show that heavy particles (density large than blood or a diameter larger than 500 Ό m) normally have small travel speeds in arteries; larger or lighter embolic particles are more likely to travel to large branches in cerebral arteries. In certain cases, all large particles go to the middle cerebral arteries; large particles with higher travel speeds in large arteries are likely to travel at more complex and tortuous trajectories; emboli raised from the basilar artery will only exit the model from branches of basilar artery and posterior cerebral arteries. A modified Circle of Willis configuration can have significant influence on particle distributions. The local branch patterns of internal carotid artery to middle cerebral artery and anterior communicating artery can have large impact on such distributions. © 2014 The Author(s)
STAN: a reappraisal of its clinical usefulness
The automatic analysis of fetal ECG in labor has been introduced as an adjunct of traditional cardiotocography with the aim to improve the identification of fetuses with intrapartum hypoxia. Several randomized controlled trials and meta-analyses have produced conflicting results, with the most recent randomized controlled trial not demonstrating any improvement in either neonatal outcomes or reduction in operative birth rates. The objective of this review article is to present the state of art about the use of STAN technology in labor ward
Evidence for tidal interaction and merger as the origin of galaxy morphology evolution in compact groups
We present the results of a morphological study based on NIR images of 25
galaxies, with different levels of nuclear activity, in 8 Compact Groups of
Galaxies (CGs). We perform independently two different analysis: a isophotal
study and a study of morphological asymmetries. The results yielded by the two
analysis are highly consistent. For the first time, it is possible to show that
deviations from pure ellipses are produced by inhomogeneous stellar mass
distributions related to galaxy interactions and mergers. We find evidence of
mass asymmetries in 74% of the galaxies in our sample. In 59% of these cases,
the asymmetries come in pairs, and are consistent with tidal effects produced
by the proximity of companion galaxies. The symmetric galaxies are generally
small in size or mass, inactive, and have an early-type morphology. In 20% of
the galaxies we find evidence for cannibalism. In 36% of the early-type
galaxies the color gradient is positive (blue nucleus) or flat. Summing up
these results, as much as 52% of the galaxies in our sample could show evidence
of an on going or past mergers. Our observations suggest that galaxies in CGs
merge more frequently under ``dry'' conditions. The high frequency of
interacting and merging galaxies observed in our study is consistent with the
bias of our sample towards CGs of type B, which represents the most active
phase in the evolution of the groups. In these groups we also find a strong
correlation between asymmetries and nuclear activity in early-type galaxies.
This correlation allows us to identify tidal interactions and mergers as the
cause of galaxy morphology transformation in CGs.[abridge]Comment: 64 pages, 35 figures. Accepted for publication in Ap
Arm position as a source of error in blood pressure measurement
The present study was designed to assess the value of correct positioning of a patient's arm when measuring blood pressure (BP). A total of 181 subjects were examined, 141 hypertensives on treatment, 25 untreated hypertensives, 15 normotensives. All the subjects underwent three BP measurements after a 5-min resting period in supine position. Then two BP readings were recorded in standing position with the arm either positioned by the patient's side or supported passively at patient's heart level. Average systolic BP (SBP) in standing position were 144.6 +/- 20.2 mmHg with the arm at the side and 136.4 +/- 21.1 mmHg with the arm at the heart level (p less than 0.001); average diastolic pressures were 99.0 +/- 12.0 mmHg and 90.2 +/- 12.3 mmHg (p less than 0.001), respectively. A fall in SBP greater than or equal to 20 mmHg from the supine to the upright position was detected in 18.2% of cases when measurement was performed at heart level; such a reduction was inapparent in two-thirds of cases when the arm was placed at the patient's body side. Incorrect positioning of a patient's arm during BP measurements in standing position leads to overestimation of BP values and masks the presence of postural hypotension
Awareness, treatment, and control of hypertension in the elderly in a general practice experience
In 3858 ambulatory elderly people (age greater than or equal to 65 years) prevalence of hypertension was 67.8%. The hypertensive status was unknown to both the doctor and the patient in 21.4% of cases. More than 90% of known hypertensives were treated, but hypertension could be considered as controlled in less than 30% of them
Anxiety and Expressed Emotion in a Sample of Obese Patients
INTRODUCTION Expressed Emotion (EE) is a measure of the intensity of the affective family climate and
plays a role in disease course and outcome. Especially in urban settings, obesity is a severe problem with
serious implications as far as health risks are concerned. Having a high EE caregiver has been suggested
to correlate with a worse treatment compliance in obese patients.
OBJECTIVES To measure level of EE, stressful events and anxiety in obese patients and their caregivers;
to investigate the possible correlations between compliance with treatment and emotional temperature of
families.
METHODS We have already recruited more than 150 obese patients and their caregivers. Assessment
included: Level of Expressed Emotion Scale (LEE), one version for patients and one for relatives in order to
evaluate 4 dimensions: intrusiveness, emotional response, attitude toward disease, tolerance and
expectation; the Paykel\u2019s Interview for Recent Life Events; STAI Y1 concerning state anxiety and STAI Y2
concerning trait anxiety. Furthermore we collected demographic characteristics and BMI (Body Mass Index).
RESULTS Data collection and analyses are still ongoing. Preliminary results suggest a correlation between
obesity and level of anxiety. We expect to find a correlation between level of EE and variation of BMI.
CONCLUSIONS Levels of EE and anxiety should be considered when planning treatment interventions to
enhance compliance in obese patients and to support change in their life-style
Pengendalian Frekuensi Dengan Menggunakan Kontrol Fuzzy Prediktif Pada Simulator Plant Turbin-Generator Pada PLTU
Sistem pembangkit dirasakan sangat perlu guna memenuhi kebutuhan tenaga listrik yang semakin meningkat, kestabilan sangat dibutuhkan pada proses pembangkit sehingga sistem pengendalian digunakan untuk menjaga variabel proses tersebut tetap stabil. Salah satunya adalah dengan melakukan pengendali frekuensi pada tubin-generator suatu pembangkit listik, contohnya PLTU (Pembangkit Listrik Tenaga Uap). Frekuensi dari turbin uap harus dijaga kestabilannya agar keluaran daya listrik di generator berjalan dengan baik. Fluktuasi frekuensi adalah salah satu kendala penyampaian daya listrik ke beban, juga waktu kembali yang tidak segera ke kondisi normal akan mengakibatkan kerusakan pada sistem seperti patahnya poros turbin-generator dan kemungkinan terjadi gangguan pada jaringan listrik, sehingga perlu dilakukan pengaturan laju aliran uap yang masuk ke turbin. Kontroler yang digunakan untuk menjaga Perubahan frekuensi adalah kontrol fuzzy prediktif, dengan penambahan gain K1 pada kontrol fuzzy prediktif sebesar 42.35 yang bekerja secara sucsessive kontroler ini dapat mengurangi error sebesar 1,04% jika sistem hanya menggunakan kontroler fuzzy pada saat terjadi Perubahan beban
- âŠ