Discrete breathers in a two-dimensional Fermi-Pasta-Ulam lattice

Using asymptotic methods, we investigate whether discrete breathers are supported by a two-dimensional Fermi-Pasta-Ulam lattice. A scalar (one-component) two-dimensional Fermi-Pasta-Ulam lattice is shown to model the charge stored within an electrical transmission lattice. A third-order multiple-scale analysis in the semi-discrete limit fails, since at this order, the lattice equations reduce to the (2+1)-dimensional cubic nonlinear Schrödinger (NLS) equation which does not support stable soliton solutions for the breather envelope. We therefore extend the analysis to higher order and find a generalised $(2+1)$-dimensional NLS equation which incorporates higher order dispersive and nonlinear terms as perturbations. We find an ellipticity criterion for the wave numbers of the carrier wave. Numerical simulations suggest that both stationary and moving breathers are supported by the system. Calculations of the energy show the expected threshold behaviour whereby the energy of breathers does {\em not} go to zero with the amplitude; we find that the energy threshold is maximised by stationary breathers, and becomes arbitrarily small as the boundary of the domain of ellipticity is approached

Asymptotic analysis of combined breather-kink modes in a Fermi-Pasta-Ulam chain

We find approximations to travelling breather solutions of the one-dimensional Fermi-Pasta-Ulam (FPU) lattice. Both bright breather and dark breather solutions are found. We find that the existence of localised (bright) solutions depends upon the coefficients of cubic and quartic terms of the potential energy, generalising an earlier inequality derived by James [CR Acad Sci Paris 332, 581, (2001)]. We use the method of multiple scales to reduce the equations of motion for the lattice to a nonlinear Schr{\"o}dinger equation at leading order and hence construct an asymptotic form for the breather. We show that in the absence of a cubic potential energy term, the lattice supports combined breathing-kink waveforms. The amplitude of breathing-kinks can be arbitrarily small, as opposed to traditional monotone kinks, which have a nonzero minimum amplitude in such systems. We also present numerical simulations of the lattice, verifying the shape and velocity of the travelling waveforms, and confirming the long-lived nature of all such modes

THE IMPACT OF MOTIVATIONAL FACTORS ON ORGANIZATIONAL LEARNING: A STUDY ON EDUCATION SECTOR OF PAKISTAN

The main purpose of this study is to investigate the motivational factors that affect the organizational learning in the education sector of Pakistan. Self-administrated questionnaire with 5 point Likert scale is used for primary data collection and research journals and articles are used for secondary data collection. The sample size of the study is consisted of hundred academic employees of different educational institutes of Lahore. SPSS is used for measuring the relationships between variables and interpretations of their relationship. Organizational learning mainly depends upon peer cooperation motivational factor. As the peer cooperation increases in an organization, it leads the organization towards learning. Peer cooperation has  a strong effect on organizational learning as a motivational factor in the education sector. A high level of peer cooperation in any organization helps in enhancing its learning. Furthermore, according to data analysis all other motivational factors used in this study i.e. working condition, recognition and reward has very small or no effect on learning of any organization. So, we can conclude that, among four different motivational factors i.e. peer cooperation, working condition, recognition and rewards, only peer cooperation has a strong relationship with organizational learning as compared to other factors

Asymptotic analysis of combined breather-kink modes in a Fermi-Pasta-Ulam chain

We find approximations to travelling breather solutions of the one-dimensional Fermi-Pasta-Ulam (FPU) lattice. Both bright breather and dark breather solutions are found. We find that the existence of localised (bright) solutions depends upon the coefficients of cubic and quartic terms of the potential energy, generalising an earlier inequality derived by James [CR Acad Sci Paris 332, 581, (2001)]. We use the method of multiple scales to reduce the equations of motion for the lattice to a nonlinear Schr{\"o}dinger equation at leading order and hence construct an asymptotic form for the breather. We show that in the absence of a cubic potential energy term, the lattice supports combined breathing-kink waveforms. The amplitude of breathing-kinks can be arbitrarily small, as opposed to traditional monotone kinks, which have a nonzero minimum amplitude in such systems. We also present numerical simulations of the lattice, verifying the shape and velocity of the travelling waveforms, and confirming the long-lived nature of all such modes

AN UNUSUAL MASS OF THE CHEST WALL IN A 7 YEARS OLD CHILD: AN ASKIN'S TUMOUR

Askin’s tumour is a primitive neuroectodermal tumour developing from the soft tissues of the chest wall. It is commonly misdiagnosed due to features similar to other round blue cell tumours. The approach for its diagnosis and treatment is complex and requires a multidisciplinary team. The recommended treatment is chemotherapy and surgical excision mainly. The prognosis is dependent on many factors. We managed a child of Askin’s tumour using modalities such as neoadjuvant chemotherapy and surgical excision and found a good response.Key words: Chest wall mass, Askin’s tumour, Ewing sarcom

Strategic design of culture for digital transformation

Industrial organizations need to take a cultural leap in order to integrate social systems with rapidly evolving digital technologies. Subsequently, aspiration for digital transformation enabled by organizational culture is ubiquitous; however, guidance in the literature on how to refresh the culture in pursuit of digital transformation strategy is underdeveloped. We conducted a diagnostic multi-case study on the organization culture in three globally renowned industrial organizations undergoing digital transformation strategy implementation. Through thematic analysis of qualitative data, we identified cultural artefacts, values in action, and assumptions that industrial organizations should refresh to enable digital transformation. It was found that forerunner industrial organizations’ approach to culture is strategically proactive and thoughtful. Furthermore, their leaders employed culture as a social control system for digital technology adoption. The research findings are summarized as an exploratory framework for the strategic design of culture for the purpose, governance, ecosystem, and organization of sociotechnical systems.© 2024 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).fi=vertaisarvioitu|en=peerReviewed

Structural challenges to adopt digital transformation in industrial organizations : A multiple case study

Digital Transformation requires significant changes in industrial organization’s setting to remain relevant in this fast-paced environment. This calls for modifications in their organizational structures. The existing organizational structures of industrial organizations are mechanistic, while, digital transformation needs organic and flexible organizational structure. Therefore, the main aim of this study is to identify the main challenges that industrial organizations face in the process of modifying their mechanistic structures into organic structures. To explore these challenges, we conducted multiple case study from three global industrial organizations. We interviewed 41 middle to high-level management personnel. The results of this study highlight six main challenges that industrial organizations need to cope for structural modifications. These challenges are structural rigidity, traditional hierarchy, silos, problems with resource allocations, organizational size and old-fashioned-leadership.© 2022. Published by AHFE Open Access. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).fi=vertaisarvioitu|en=peerReviewed

Discrete Breathers in One- and Two-Dimensional Lattices

Discrete breathers are time-periodic and spatially localised exact solutions in translationally invariant nonlinear lattices. They are generic solutions, since only moderate conditions are required for their existence. Closed analytic forms for breather solutions are generally not known. We use asymptotic methods to determine both the properties and the approximate form of discrete breather solutions in various lattices. We find the conditions for which the one-dimensional FPU chain admits breather solutions, generalising a known result for stationary breathers to include moving breathers. These conditions are verified by numerical simulations. We show that the FPU chain with quartic interaction potential supports long-lived waveforms which are combinations of a breather and a kink. The amplitude of classical monotone kinks is shown to have a nonzero minimum, whereas the amplitude of breathing-kinks can be arbitrarily small. We consider a two-dimensional FPU lattice with square rotational symmetry. An analysis to third-order in the wave amplitude is inadequate, since this leads to a partial differential equation which does not admit stable soliton solutions for the breather envelope. We overcome this by extending the analysis to higher-order, obtaining a modified partial differential equation which includes known stabilising terms. From this, we determine regions of parameter space where breather solutions are expected. Our analytic results are supported by extensive numerical simulations, which suggest that the two-dimensional square FPU lattice supports long-lived stationary and moving breather modes. We find no restriction upon the direction in which breathers can travel through the lattice. Asymptotic estimates for the breather energy confirm that there is a minimum threshold energy which must be exceeded for breathers to exist in the two-dimensional lattice. We find similar results for a two-dimensional FPU lattice with hexagonal rotational symmetry

Upregulation of Transglutaminase andε(γ-Glutamyl)-Lysine in the Fisher-Lewis Rat Model of Chronic Allograft Nephropathy

Background. Tissue transglutaminase (TG2), a cross-linking enzyme, modulates deposition of extracellular matrix protein in renal fibrosis. This study aimed to examine TG2 and its cross-link product ε(γ-glutamyl)-lysine in the Fisher-Lewis rat renal transplantation (RTx) model of chronic allograft nephropathy (CAN). Materials and Methods. Left renal grafts from male Fisher and Lewis were transplanted into Lewis rats, generating allografts and isografts, respectively. Blood pressure, renal function, and proteinuria were monitored for up to 52 weeks. At termination, CAN was assessed in the renal tissue by light and electron microscopy, TG2 and ε(γ-glutamyl)-lysine by immunofluorescence, and the urinary ε(γ-glutamyl)-lysine by high performance liquid chromatography. Results. Compared to the isograft, the allografts were hypertensive, proteinuric, and uraemic and developed CAN. Extracellular TG2 (glomerulus: 64.55 + 17.61 versus 2.11 + 0.17, P<0.001; interstitium: 13.72 + 1.62 versus 3.19 + 0.44, P<0.001), ε(γ-glutamyl)-lysine (glomerulus: 21.74 + 2.71 versus 1.98 + 0.37, P<0.01; interstitium: 37.96 + 17.06 versus 0.42 + 0.11, P<0.05), TG2 enzyme activity (1.09 + 0.13 versus 0.41 + 0.03 nmol/h/mg protein, P<0.05), TG2 mRNA (20-fold rise), and urinary ε(γ-glutamyl)-lysine (534.2 + 198.4 nmol/24 h versus 57.2 + 4.1 nmol/24 h,P<0.05) levels were significantly elevated in the allografts and showed a positive linear correlation with tubulointerstitial fibrosis. Conclusion. CAN was associated with upregulation of renal TG2 pathway, which has a potential for pharmacological intervention. The elevated urinary ε(γ-glutamyl)-lysine, measured for the first time in RTx, is a potential biomarker of CA

Role of Endoscopic Third Ventriculostomy in Congenital Obstructive Hydrocephalus

Object:&nbsp;&nbsp;To improve the care of Obstructive Hydrocephalic infants, from six months to twelve months and to evaluate the efficacy and complications of Endoscopic Third Ventriculostomy (ETV). Materials and Methods:&nbsp;&nbsp;The study was conducted in the Department of Neurosurgery PGMI, Lahore General Hospital, Lahore from July 2007 to June 2008. Total numbers of patients were 30, which were divided into two equal groups. Group A (15 patients) underwent Endoscopic Third Ventriculostomy (ETV) and Ventriculo-peritoneal VP Shunt were done in Group B (15 patients). Cases were selected randomly. Results: &nbsp;The mean age for Group A was 9 months and for Group B was 8 months Endoscopic Third Ventriculo-stomy (ETV) procedure found successful in older than 8 months of age while ventriculoperitoneal VP Shunt procedure found successful in all age groups. Before procedure mean head circumference for Group A was 50.86 cm and for Group B was 50.84 cm. After one year follow up mean head circumference in Endoscopic Third Ventriculostomy (ETV) Group was 50.18 cm and in VP Shunt Group was 47.38 cm. Primary success in Endoscopic Third Ventriculostomy (ETV) Group was 53.3% (8 out of 15), whereas in VP Shunt Group it was 66.7% (10 out of 15).&nbsp; Conclusion:&nbsp;&nbsp;Although results are same in both groups but Endoscopic Third Ventriculostomy (ETV) Group remain shunt free. Endoscopic Third Ventriculostomy seems to be an effective alternative than VP Shunt in the management of Hydrocephalus in infants provided careful patient selection is done and surgeon is competent enough with Endoscopic Third Ventriculostomy technique