Four electrons in a two-leg Hubbard ladder: exact ground states

In the case of a two-leg Hubbard ladder we present a procedure which allows the exact deduction of the ground state for the four particle problem in arbitrary large lattice system, in a tractable manner, which involves only a reduced Hilbert space region containing the ground state. In the presented case, the method leads to nine analytic, linear, and coupled equations providing the ground state. The procedure which is applicable to few particle problems and other systems as well is based on an r-space representation of the wave functions and construction of symmetry adapted orthogonal basis wave vectors describing the Hilbert space region containing the ground state. Once the ground state is deduced, a complete quantum mechanical characterization of the studied state can be given. Since the analytic structure of the ground state becomes visible during the use of the method, its importance is not reduced only to the understanding of theoretical aspects connected to exact descriptions or potential numerical approximation scheme developments, but is relevant as well for a large number of potential technological application possibilities placed between nano-devices and quantum calculations, where the few particle behavior and deep understanding are important key aspects to know.Comment: 19 pages, 5 figure

Filaggrin mutations in relation to skin barrier and atopic dermatitis in early infancy

Background Loss-of-function mutations in the skin barrier gene filaggrin (FLG) increase the risk of atopic dermatitis (AD), but their role in skin barrier function, dry skin and eczema in infancy is unclear. Objectives To determine the role of FLG mutations in impaired skin barrier function, dry skin, eczema and AD at 3 months of age and throughout infancy. Methods FLG mutations were analysed in 1836 infants in the Scandinavian population-based PreventADALL study. Transepidermal water loss (TEWL), dry skin, eczema and AD were assessed at 3, 6 and 12 months of age. Results FLG mutations were observed in 166 (9%) infants. At 3 months, carrying FLG mutations was not associated with impaired skin barrier function (TEWL > 11 center dot 3 g m(-2) h(-1)) or dry skin, but was associated with eczema [odds ratio (OR) 2 center dot 89, 95% confidence interval (CI) 1 center dot 95-4 center dot 28; P < 0 center dot 001]. At 6 months, mutation carriers had significantly higher TEWL than nonmutation carriers [mean 9 center dot 68 (95% CI 8 center dot 69-10 center dot 68) vs. 8 center dot 24 (95% CI 7 center dot 97-8 center dot 15), P < 0 center dot 01], and at 3 and 6 months mutation carriers had an increased risk of dry skin on the trunk (OR 1 center dot 87, 95% CI 1 center dot 25-2 center dot 80; P = 0 center dot 002 and OR 2 center dot 44, 95% CI 1 center dot 51-3 center dot 95; P < 0 center dot 001) or extensor limb surfaces (OR 1 center dot 52, 95% CI 1 center dot 04-2 center dot 22; P = 0 center dot 028 and OR 1 center dot 74, 95% CI 1 center dot 17-2 center dot 57; P = 0 center dot 005). FLG mutations were associated with eczema and AD in infancy. Conclusions FLG mutations were not associated with impaired skin barrier function or dry skin in general at 3 months of age, but increased the risk for eczema, and for dry skin on the trunk and extensor limb surfaces at 3 and 6 months.Peer reviewe

Acute kidney disease and renal recovery : consensus report of the Acute Disease Quality Initiative (ADQI) 16 Workgroup

Consensus definitions have been reached for both acute kidney injury (AKI) and chronic kidney disease (CKD) and these definitions are now routinely used in research and clinical practice. The KDIGO guideline defines AKI as an abrupt decrease in kidney function occurring over 7 days or less, whereas CKD is defined by the persistence of kidney disease for a period of > 90 days. AKI and CKD are increasingly recognized as related entities and in some instances probably represent a continuum of the disease process. For patients in whom pathophysiologic processes are ongoing, the term acute kidney disease (AKD) has been proposed to define the course of disease after AKI; however, definitions of AKD and strategies for the management of patients with AKD are not currently available. In this consensus statement, the Acute Disease Quality Initiative (ADQI) proposes definitions, staging criteria for AKD, and strategies for the management of affected patients. We also make recommendations for areas of future research, which aim to improve understanding of the underlying processes and improve outcomes for patients with AKD

Modelling the neuropathology of lysosomal storage disorders through disease-specific human induced pluripotent stem cells

Mucopolysaccharidosis II (MPS II) is a lysosomal storage disorder (LSD), caused by iduronate 2-sulphatase (IDS) enzyme dysfunction. The neuropathology of the disease is not well understood, although the neural symptoms are currently incurable. MPS II-patient derived iPSC lines were established and differentiated to neuronal lineage. The disease phenotype was confirmed by IDS enzyme and glycosaminoglycan assay. MPS II neuronal precursor cells (NPCs) showed significantly decreased self-renewal capacity, while their cortical neuronal differentiation potential was not affected. Major structural alterations in the ER and Golgi complex, accumulation of storage vacuoles, and increased apoptosis were observed both at protein expression and ultrastructural level in the MPS II neuronal cells, which was more pronounced in GFAP + astrocytes, with increased LAMP2 expression but unchanged in their RAB7 compartment. Based on these finding we hypothesize that lysosomal membrane protein (LMP) carrier vesicles have an initiating role in the formation of storage vacuoles leading to impaired lysosomal function. In conclusion, a novel human MPS II disease model was established for the first time which recapitulates the in vitro neuropathology of the disorder, providing novel information on the disease mechanism which allows better understanding of further lysosomal storage disorders and facilitates drug testing and gene therapy approaches

Handling Conflicts in Depth-First Search for LTL Tableau to Debug Compliance Based Languages

Providing adequate tools to tackle the problem of inconsistent compliance rules is a critical research topic. This problem is of paramount importance to achieve automatic support for early declarative design and to support evolution of rules in contract-based or service-based systems. In this paper we investigate the problem of extracting temporal unsatisfiable cores in order to detect the inconsistent part of a specification. We extend conflict-driven SAT-solver to provide a new conflict-driven depth-first-search solver for temporal logic. We use this solver to compute LTL unsatisfiable cores without re-exploring the history of the solver.Comment: In Proceedings FLACOS 2011, arXiv:1109.239

Primary care obesity management in Hungary: evaluation of the knowledge, practice and attitudes of family physicians

BACKGROUND: Obesity, a threatening pandemic, has an important public health implication. Before proper medication is available, primary care providers will have a distinguished role in prevention and management. Their performance may be influenced by many factors but their personal motivation is still an under-researched area. METHOD: The knowledge, attitudes and practice were reviewed in this questionnaire study involving a representative sample of 10% of all Hungarian family physicians. In different settings, 521 practitioners (448 GPs and 73 residents/vocational trainees) were questioned using a validated questionnaire. RESULTS: The knowledge about multimorbidity, a main consequence of obesity, was balanced.Only 51% of the GPs were aware of the diagnostic threshold for obesity; awareness being higher in cities (60%) and the highest among residents (90%). They also considered obesity an illness rather than an aesthetic issue.There were wider differences regarding attitudes and practice, influenced by the the doctors' age, gender, known BMI, previous qualification, less by working location.GPs with qualification in family medicine alone considered obesity management as higher professional satisfaction, compared to physicians who had previously other board qualification (77%vs68%). They measured their patients' waist circumference and waist/hip ratio (72%vs62%) more frequently, provided the obese with dietary advice more often, while this service was less frequent among capital-based doctors who accepted the self-reported body weight dates by patients more frequently / commonly. Similar reduced activity and weight-measurement in outdoor clothing were more typical among older doctors.Diagnosis based on BMI alone was the highest in cities (85%). Consultations were significantly shorter in practices with a higher number of enrolled patients and were longer by female providers who consulted longer with patients about the suspected causes of developing obesity (65%vs44%) and offered dietary records for patients significantly more frequently (65%vs52%). Most of the younger doctors agreed that obesity management was a primary care issue.Doctors in the normal BMI range were unanimous that they should be a model for their patients (94%vs81%). CONCLUSION: More education of primary care physicians, available practical guidelines and higher community involvement are needed to improve the obesity management in Hungary