557 research outputs found
Exact Eigenfunctions of -Body system with Quadratic Pair Potential
We obtain all the exact eigenvalues and the corresponding eigenfunctions of
-body Bose and Fermi systems with Quadratic Pair Potentials in one
dimension. The originally existed first excited state level is missing in one
dimension, which results from the operation of symmetry or antisymmetry of
identical particles. In two and higher dimensions, we give all the eigenvalues
and the analytical ground state wave functions and the number of degeneracy.
Through the comparison with Avinash Khare's results, we have perfected his
results.Comment: 7 pages,1 figur
Surgical Management of Inguinal Hernias at Bugando Medical Centre in Northwestern Tanzania: Our Experiences in a Resource-Limited Setting.
Inguinal hernia repair remains the commonest operation performed by general surgeons all over the world. There is paucity of published data on surgical management of inguinal hernias in our environment. This study is intended to describe our own experiences in the surgical management of inguinal hernias and compare our results with that reported in literature. A descriptive prospective study was conducted at Bugando Medical Centre in northwestern Tanzania. Ethical approval to conduct the study was obtained from relevant authorities before the commencement of the study. Statistical data analysis was done using SPSS software version 17.0. A total of 452 patients with inguinal hernias were enrolled in the study. The median age of patients was 36 years (range 3 months to 78 years). Males outnumbered females by a ratio of 36.7:1. This gender deference was statistically significant (P=0.003). Most patients (44.7%) presented late (more than five years of onset of hernia). Inguinoscrotal hernia (66.8%) was the commonest presentation. At presentation, 208 (46.0%) patients had reducible hernia, 110 (24.3%) had irreducible hernia, 84 (18.6%) and 50(11.1%) patients had obstructed and strangulated hernias respectively. The majority of patients (53.1%) had right sided inguinal hernia with a right-to-left ratio of 2.1: 1. Ninety-two (20.4%) patients had bilateral inguinal hernias. 296 (65.5%) patients had indirect hernia, 102 (22.6%) had direct hernia and 54 (11.9%) had both indirect and direct types (pantaloon hernia). All patients in this study underwent open herniorrhaphy. The majority of patients (61.5%) underwent elective herniorrhaphy under spinal anaesthesia (69.2%). Local anaesthesia was used in only 1.1% of cases. Bowel resection was required in 15.9% of patients. Modified Bassini's repair (79.9%) was the most common technique of posterior wall repair of the inguinal canal. Lichtenstein mesh repair was used in only one (0.2%) patient. Complication rate was 12.4% and it was significantly higher in emergency herniorrhaphy than in elective herniorrhaphy (P=0.002). The median length of hospital stay was 8 days and it was significantly longer in patients with advanced age, delayed admission, concomitant medical illness, high ASA class, the need for bowel resection and in those with surgical repair performed under general anesthesia (P<0.001). Mortality rate was 9.7%. Longer duration of symptoms, late hospitalization, coexisting disease, high ASA class, delayed operation, the need for bowel resection and presence of complications were found to be predictors of mortality (P<0.001). Inguinal hernias continue to be a source of morbidity and mortality in our centre. Early presentation and elective repair of inguinal hernias is pivotal in order to eliminate the morbidity and mortality associated with this very common problem
From Letters to Logistics - The enabling role of a lean transformation programme in a national postal service: The case of An Post, Ireland
From Letters to Logistics - The enabling role of a lean transformation programme
in a national postal service: The case of An Post, Ireland
Seamus O’Reilly (Cork University Business School), David Murray (An Post) and Joe Aherne (Leading Edge Group)
Abstract
Purpose
This paper investigates the role of a lean transformation programme in supporting the transition of a national postal (mail) service from a traditional letter delivery service to a competitive parcel delivery service.
Methodology
Given the objective an intrinsic case study (Stake, 2005) approach was adopted, as this specific case was of interest. To support this approach the researchers had access to a range of data sources including, archives (e.g. strategy documents), reports (e.g. project reports and outputs), and access to management involved in the transformation programme.
Findings
The findings highlight the fundamental role of leadership, at all levels, and organisational culture in supporting a LSS transformation programme. The balance between dedicated experts and larger projects on one hand and wider engagement throughout the organisation on the other hand was instrumental to embedding an LSS culture. In this regard frontline managers had a key role to play.
Limitations
As with any case study research we must be careful when generalising the findings. Furthermore, given the relatively recent strategy deployment within the case organisation, further follow-up studies are required to establish the sustainability of the culture change and benefits achieved.
Originality
On the basis of a systematic literature review, Danese et al. (2018) call for exploratory case studies/action research to better understand how lean could be implemented in public sector. This intrinsic case approach adopted responds to this.
Practical Implications
The study links research and practice through assessment of the organisational journey and consideration of the findings in the context of success factors identified in the literature. Management behaviour and practices at all levels were fundamental to achieving a LSS transformation culture, including ‘go and see’ for senior management and active daily huddles facilitated by frontline management.
Key Words: Lean Six Sigma, Public Sector, Service Sector, National Mail Service
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PS18kh: A New Tidal Disruption Event with a Non-axisymmetric Accretion Disk
We present the discovery of PS18kh, a tidal disruption event discovered at the center of SDSS J075654.53+341543.6 (d ≃ 322 Mpc) by the Pan-STARRS Survey for Transients. Our data set includes pre-discovery survey data from Pan-STARRS, the All-sky Automated Survey for Supernovae, and the Asteroid Terrestrial-impact Last Alert System as well as high-cadence, multiwavelength follow-up data from ground-based telescopes and Swift, spanning from 56 days before peak light until 75 days after. The optical/UV emission from PS18kh is well-fit as a blackbody with temperatures ranging from T ≃ 12,000 K to T ≃ 25,000 K and it peaked at a luminosity of L ≃ 8.8 × 10 erg s . PS18kh radiated E = (3.45 ± 0.22) × 10 erg over the period of observation, with (1.42 ± 0.20) × 10 erg being released during the rise to peak. Spectra of PS18kh show a changing, boxy/double-peaked Hα emission feature, which becomes more prominent over time. We use models of non-axisymmetric accretion disks to describe the profile of the Hα line and its evolution. We find that at early times the high accretion rate leads the disk to emit a wind which modifies the shape of the line profile and makes it bell-shaped. At late times, the wind becomes optically thin, allowing the non-axisymmetric perturbations to show up in the line profile. The line-emitting portion of the disk extends from r ∼ 60r to an outer radius of r ∼ 1400r and the perturbations can be represented either as an eccentricity in the outer rings of the disk or as a spiral arm in the inner disk. 43 -1 50 50 in g out
Depression and sickness behavior are Janus-faced responses to shared inflammatory pathways
It is of considerable translational importance whether depression is a form or a consequence of sickness behavior. Sickness behavior is a behavioral complex induced by infections and immune trauma and mediated by pro-inflammatory cytokines. It is an adaptive response that enhances recovery by conserving energy to combat acute inflammation. There are considerable phenomenological similarities between sickness behavior and depression, for example, behavioral inhibition, anorexia and weight loss, and melancholic (anhedonia), physio-somatic (fatigue, hyperalgesia, malaise), anxiety and neurocognitive symptoms. In clinical depression, however, a transition occurs to sensitization of immuno-inflammatory pathways, progressive damage by oxidative and nitrosative stress to lipids, proteins, and DNA, and autoimmune responses directed against self-epitopes. The latter mechanisms are the substrate of a neuroprogressive process, whereby multiple depressive episodes cause neural tissue damage and consequent functional and cognitive sequelae. Thus, shared immuno-inflammatory pathways underpin the physiology of sickness behavior and the pathophysiology of clinical depression explaining their partially overlapping phenomenology. Inflammation may provoke a Janus-faced response with a good, acute side, generating protective inflammation through sickness behavior and a bad, chronic side, for example, clinical depression, a lifelong disorder with positive feedback loops between (neuro)inflammation and (neuro)degenerative processes following less well defined triggers
Making waves round a structured cloak: lattices, negative refraction and fringes
Using the framework of transformation optics, this paper presents a detailed analysis of a non-singular square cloak for acoustic, out-of-plane shear elastic and electromagnetic waves. Analysis of wave propagation through the cloak is presented and accompanied by numerical illustrations. The efficacy of the regularized cloak is demonstrated and an objective numerical measure of the quality of the cloaking effect is provided. It is demonstrated that the cloaking effect persists over a wide range of frequencies. As a demonstration of the effectiveness of the regularized cloak, a Young’s double slit experiment is presented. The stability of the interference pattern is examined when a cloaked and uncloaked obstacle are successively placed in front of one of the apertures. This novel link with a well-known quantum mechanical experiment provides an additional method through which the quality of cloaks may be examined. In the second half of the paper, it is shown that an approximate cloak may be constructed using a discrete lattice structure. The efficiency of the approximate lattice cloak is analysed and a series of illustrative simulations presented. It is demonstrated that effective cloaking may be obtained by using a relatively simple lattice structure, particularly, in the low-frequency regime
Phase-space consistency of stellar dynamical models determined by separable augmented densities
Assuming the separable augmented density, it is always possible to construct
a distribution function of a spherical population with any given density and
anisotropy. We consider under what conditions the distribution constructed as
such is in fact non-negative everywhere in the accessible phase-space. We first
generalize known necessary conditions on the augmented density using fractional
calculus. The condition on the radius part R(r^2) (whose logarithmic derivative
is the anisotropy parameter) is equivalent to the complete monotonicity of
R(1/w)/w. The condition on the potential part on the other hand is given by its
derivative up to any order not greater than (3/2-beta) being non-negative where
beta is the central anisotropy parameter. We also derive a specialized
inversion formula for the distribution from the separable augmented density,
which leads to sufficient conditions on separable augmented densities for the
non-negativity of the distribution. The last generalizes the similar condition
derived earlier for the generalized Cuddeford system to arbitrary separable
systems.Comment: accepted for the publication in MNRAS, 12 journal pages (7pp in main
body + 4 appendices
A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)
Meeting abstrac
Multi-messenger observations of a binary neutron star merger
On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta
Feasibility study on pre or postoperative accelerated radiotherapy (POP-ART) in breast cancer patients
Background: In early-stage breast cancer, the cornerstone of treatment is surgery. After breast-conserving surgery,
adjuvant radiotherapy has shown to improve locoregional control and overall survival rates. The use of breast
radiotherapy in the preoperative (preop) setting is far less common. Nevertheless, it might improve disease-free
survival as compared to postoperative radiotherapy. There is also a possibility of downsizing the tumour which
might lead to a lower need for mastectomy. There are some obstacles that complicate its introduction into daily
practice. It may complicate surgery or lead to an increase in wound complications or delayed wound healing.
Another fear of preop radiotherapy is delaying surgery for too long. At Ghent University Hospital, we have
experience with a 5-fraction radiotherapy schedule allowing radiotherapy delivery in a very short time span.
Methods: Twenty female breast cancer patients with non-metastatic disease receiving preop chemotherapy will be
randomized between preop or postoperative radiotherapy. The feasibility of preop radiotherapy will be evaluated
based on overall treatment time. All patients will be treated in 5 fractions of 5.7 Gy to the whole breast with a
simultaneous integrated boost to the tumour/tumour bed of 5 × 6.2 Gy. In case of lymph node irradiation, the
lymph node regions will receive a dose of 27 Gy in 5 fractions of 5.4 Gy. The total duration of therapy will be 10 to
12 days. In the preop group, overall treatment time is defined as the time between diagnosis and the day of last
surgery, in the postop group between diagnosis and last irradiation fraction. Toxicity related to surgery, radio-, and
chemotherapy will be evaluated on dedicated case-report forms at predefined time points. Tumour response will
be evaluated on the pathology report and on MRI at baseline and in the interval between chemotherapy and
surgery.
Discussion: The primary objective of the trial is to investigate the feasibility of preop radiotherapy. Secondary
objectives are to search for biomarkers of response and toxicity and identify the involved cell death mechanisms
and the effect of preop breast radiotherapy on the in-situ immune micro-environment
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