Meta-nematic transitions in a bilayer system: Application to the bilayer ruthenate

It was suggested that the two consecutive metamagnetic transitions and the large residual resistivity discovered in Sr$_3$Ru$_2$O$_7$ can be understood via the nematic order and its domains in a single layer system. However, a recently reported anisotropy between two longitudinal resistivities induced by tilting the magnetic field away from the c-axis cannot be explained within the single layer nematic picture. To fill the gap in our understanding within the nematic order scenario, we investigate the effects of bilayer coupling and in-plane magnetic field on the electronic nematic phases in a bilayer system. We propose that the in-plane magnetic field in the bilayer system modifies the energetics of the domain formation, since it breaks the degeneracy of two different nematic orientations. Thus the system reveals a pure nematic phase with a resistivity anisotropy in the presence of an in-plane magnetic field. In addition to the nematic phase, the bilayer coupling opens a novel route to a hidden nematic phase that preserves the x-y symmetry of the Fermi surfaces.Comment: 8 pages, 6 figure

Proximity Effect in Nb/Au/CoFe Trilayers

We have investigated the superconducting critical temperatures of Nb/Au/CoFe trilayers as a function of Au and CoFe thicknesses. Without the CoFe layer the superconducting critical temperatures of Nb/Au bilayers as a function of Au thickness follow the well-known proximity effect between a superconductor and a normal metal. The superconducting critical temperatures of Nb/Au/CoFe trilayers as a function of Au thickness exhibit a rapid initial increase in the small Au thickness region and increase slowly to a limiting value above this region, accompanied by a small oscillation of Tc. On the other hand, the superconducting critical temperatures of Nb/Au/CoFe trilayers as a function of CoFe thickness show non-monotonic behavior with a shallow dip feature. We analyzed the Tc behavior in terms of Usadel formalism and found that most features are consistent with the theory, although the small oscillation of Tc as a function of the Au thickness cannot be accounted for. We have also found quantitative values for the two interfaces: Nb/Au and Au/CoFe.Comment: 25 pages, 6 figure

Interplay between parallel and diagonal electronic nematic phases in interacting systems

An electronic nematic phase can be classified by a spontaneously broken discrete rotational symmetry of a host lattice. In a square lattice, there are two distinct nematic phases. The parallel nematic phase breaks $x$ and $y$ symmetry, while the diagonal nematic phase breaks the diagonal $(x+y)$ and anti-diagonal $(x-y)$ symmetry. We investigate the interplay between the parallel and diagonal nematic orders using mean field theory. We found that the nematic phases compete with each other, while they coexist in a finite window of parameter space. The quantum critical point between the diagonal nematic and isotropic phases exists, and its location in a phase diagram depends on the topology of the Fermi surface. We discuss the implication of our results in the context of neutron scattering and Raman spectroscopy measurements on La$_{2-x}$Sr$_x$CuO$_4$.Comment: 8 pages, 10 figure

A novel route to a finite center-of-mass momentum pairing state; current driven FFLO state

The previously studied Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state is stabilized by a magnetic field via the Zeeman coupling in spin-singlet superconductors. Here we suggest a novel route to achieve non-zero center-of-mass momentum pairing states in superconductors with Fermi surface nesting. We investigate two-dimensional superconductors under a uniform external current, which leads to a finite pair-momentum of ${\bf q}_{e}$. We find that an FFLO state with a spontaneous pair-momentum of ${\bf q}_{s}$ is stabilized above a certain critical current which depends on the direction of the external current. A finite ${\bf q}_s$ arises in order to make the total pair-momentum of ${\bf q}_t(={\bf q}_s + {\bf q}_e)$ perpendicular to the nesting vector, which lowers the free energy of the FFLO state, as compared to the superconducting and normal states. We also suggest experimental signatures of the FFLO state.Comment: 4 pages, 5 figure

Railway defect detection method: A review

The railway is indeed one of the main transportations means in the world. However, with the rapid development and advancement of the railway industries, more railways accidents occur mainly due to its defects which result in economic losses. Traditionally, the railway defect detections process which is deems to be dirty, difficult and dangerous are done manually by the railway maintenance workers. In the recent years, many sophisticated equipment such as portable detectors, track inspection trolleys, track comprehensive inspection vehicles, etc had been developed. This article outlines two main mode of inspection namely static and dynamic inspection, which are commonly used in the railway defect detection and maintenance work. Furthermore, the railway inspection equipment used by the major countries are summarized and the impact on railway inspection based on deep learning and artificial intelligence are appropriately predicted

L'anémie à l'accouchement à Lomé (Togo) : prévalence, facteurs de risque et répercussions chez le nouveau-né

Une étude de prévalence réalisée à Lomé (Togo) a porté sur 125 couples mère-nouveau-né : 48% des mères et 30% des nouveaux-nés sont anémiques d'après les seuils de l'OMS. Trois mères sur quatre ont au moins un indicateur de carence en fer et celle-ci est le déterminant principal de l'anémie. Soixante huit pour cent ont une carence en folates, sans répercussion sur les paramètres hématologiques. Lorsque la carence en fer maternelle est grave (fer sérique <7umol), le fer sérique du nouveau-né est abaissé, ce qui témoigne d'une réduction de l'apport de fer au foetus. Le statut folique des nouveaux-nés est meilleur lorsque les mères ont reçu de l'acide folique pendant leur grossesse. Une supplémentation de ferro-folique systématique est donc nécessaire pendant la grossesse et serait bénéfique à la mère et à l'enfant. Les consultations prénatales devraient servir de cadre à la supplémentation. Leur fréquentation par 98% des femmes enceintes permet d'envisager une bonne couverture pour une telle intervention. (Résumé d'auteur

A review of risk management process in construction projects of developing countries

In the construction industry, risk management concept is a less popular technique. There are three main stages in the systematic approach to risk management in construction industry. These stages include: a) risk response; b) risk analysis and evaluation; and c) risk identification. The high risk related to construction business affects each of its participants; while operational analysis and management of construction related risks remain an enormous task to practitioners of the industry. This paper tends towards reviewing the existing literature on construction project risk managements in developing countries specifically on risk management process. The literature lacks ample risk management process approach capable of capturing risk impact on diverse project objectives. This literature review aims at discovering the frequently used techniques in risk identification and analysis. It also attempts to identify response to clarifying the different classifications of risk sources in the existing literature of developing countries, and to identify the future research directions on project risks in the area of construction in developing countries

Underlying causes of construction project delay: A review

Delay is a worldwide problem which normally occurs in every project. Delay of the project occurs when a period of time of the completion date is late or postponed. Since the project is delayed, the cost of the project will have escalation which will risk the contractors. Instead of getting a benefit from the project, they gain losses. Similarly, other construction projects in different countries are prone to face delays. The aim of this study is to summarise the causes of delay in the construction project from previous study. Regarding the causes of construction project delay, the major countries in the world have faced slow decision making, poor site management and supervision, shortage of labour, changes of scope of work during construction, late in revising and approving design documents, etc. The identification of important delay causes helps a contractor to plan well before the project start

Key constraint in construction industry: A review

Constraint is a limitation of a situation, agency, or force that obstructs movement toward a goal or purpose. There are several sorts of constraints that might impact building projects. During the early phases of a project, constraints should be recognized and explained in as much detail as possible, so that knowledge of them and their potential impact can be handled. The aim of this study is to identify types of constraints that might occur in the construction industry which may affect the time, cost and scope of the project. The study was carried out on the basis of a literature review with the result and findings of previous researchers. The result and findings from the previous researcher have been analysing in the table together with the method of analysis that being used by them in order to carry out the study. From the review, it can be summarized that the key of constraints can be divided into five major elements. There are Environmental constraints, Legal Constraints, Environmental Constraints, Technical Constraints and Social Constraints. Therefore, by doing this investigation, it will help to give a better solution and performance in term of time, cost and scope of the project by classifying and limiting the constraints in the construction industry especially at an early stage in the project planning and schedule

Geographic Distribution of Childbirth among Adolescents in Cameroon from 2003 to 2005

Objective. To determine the frequency and the trend of adolescents (10–19 years) in childbirth within a period of 3 years in referral maternity units in Cameroon. Method. Descriptive and retrospective study for a 3-year period (2003–2005) in referral maternity units headed by a qualified Obstetrician-Gynecologist. We analyzed the trend and geographic distribution of 8222 adolescent deliveries over 3 years. Epi Info 3.5 software was used for data analysis. Chi square test for trend was used to assess the contribution of adolescent deliveries over years. The trend was considered significant if P < .05. Results. During the period of the study, there was a total of 8387 deliveries. We excluded 165 women because of lack of information about age. We therefore included a total of 8222 adolescent deliveries. Overall, the contribution of adolescents to deliveries ranged from 6.87% to 26.51%, depending on the region with a national mean of 14.23%. Adolescents aged 16 or less contributed to 2.82% of deliveries while those aged from 17 to 19 contributed to 11.41%. The contribution of adolescents to deliveries decreased significantly over 3 years (P < .0001). Conclusion. The study underscores the importance of Public Health programs in strengthening maternity services for adolescents in Cameroon while taking into consideration geographic differences