Novel thermal annealing methodology for permanent tuning polymer optical fiber Bragg gratings to longer wavelengths

The Bragg wavelength of a polymer optical fiber Bragg grating can be permanently shifted by utilizing the thermal annealing method. In all the reported fiber annealing cases, the authors were able to tune the Bragg wavelength only to shorter wavelengths, since the polymer fiber shrinks in length during the annealing process. This article demonstrates a novel thermal annealing methodology for permanently tuning polymer optical fiber Bragg gratings to any desirable spectral position, including longer wavelengths. Stretching the polymer optical fiber during the annealing process, the period of Bragg grating, which is directly related with the Bragg wavelength, can become permanently longer. The methodology presented in this article can be used to multiplex polymer optical fiber Bragg gratings at any desirable spectral position utilizing only one phase-mask for their photo-inscription, reducing thus their fabrication cost in an industrial setting

AI-driven web API testing

Testing of web APIs is nowadays more critical than ever before, as they are the current standard for software integration. A bug in an organization’s web API could have a huge impact both in ternally (services relying on that API) and externally (third-party applications and end users). Most existing tools and testing ap proaches require writing tests or instrumenting the system under test (SUT). The main aim of this dissertation is to take web API testing to an unprecedented level of automation and thoroughness. To this end, we plan to apply artificial intelligence (AI) techniques for the autonomous detection of software failures. Specifically, the idea is to develop intelligent programs (we call them “bots”) ca pable of generating hundreds, thousands or even millions of test inputs and to evaluate whether the test outputs are correct based on: 1) patterns learned from previous executions of the SUT; and 2) knowledge gained from analyzing thousands of similar programs. Evaluation results of our initial prototype are promising, with bugs being automatically detected in some real-world APIs.Ministerio de Economía y Competitividad BELI (TIN2015-70560-R)Ministerio de Ciencia, Innovación y Universidades RTI2018-101204-B-C21 (HORATIO)Ministerio de Educación, Cultura y Deporte FPU17/0407

Locking bandwidth of two laterally coupled semiconductor lasers subject to optical injection

We report here for the first time (to our knowledge), a new and universal mechanism by which a two-element laser array is locked to external optical injection and admits stably injection-locked states within a nontrivial trapezoidal region. The rate equations for the system are studied both analytically and numerically. We derive a simple mathematical expression for the locking conditions, which reveals that two parallel saddle-node bifurcation branches, not reported for conventional single lasers subject to optical injection, delimit the injection locking range and its width. Important parameters are the linewidth enhancement factor, the laser separation, and the frequency offset between the two laterally-coupled lasers; the influence of these parameters on locking conditions is explored comprehensively. Our analytic approximations are validated numerically by using a path continuation technique as well as direct numerical integration of the rate equations. More importantly, our results are not restricted by waveguiding structures and uncover a generic locking behavior in the lateral arrays in the presence of injection

Quantum Optics and Photonics

Contains reports on nine research projects.U.S. Air Force - Office of Scientific Research (Contract F49620-82-C-0091)U.S. Air Force - Rome Air Development CenterJoint Services Electronics Program (Contract DAAG29-83-K-0003)National Science Foundation Grant (Grant PHY 82-710369

Parents’ marital status and child physical abuse potential: the mediation of depression symptoms

Informed by a social interactional framework of stress and parenting, the aim of this study was to examine the mediating effect of depression symptoms on the asso- ciation between parents’ marital status (married and divorced parents) and child physical abuse potential, in a Portuguese community sample. It was hypothesized that the possible observed differences between divorced and married parents in the child physical abuse potential would be explained by their depression symptoms. Parents (N = 892) were assessed in their marital status, severity of depression symptoms and child physical abuse potential. Results showed that, when compared with married parents, divorced parents had higher child physical abuse potential. However, parents’ depression symptomatology was found as a mediator of the effect of marital status differences on child physical abuse potential. The influence of the status of divorced parents on the increase of child physical abuse potential was explained by the increase of the parents’ depression symptoms. This finding suggested that parents’ divorced status had no longer an effect on child physical abuse potential when parents’ depression symptomatology was tested as a mediator vari- able. The present mediation model explained 47 % of the variability in the child physical abuse potential score. Prac- tical implications of these findings for prevention and psy- chological intervention are also discussed.info:eu-repo/semantics/publishedVersio

The Portuguese version of the Psychological Adjustment to Separation Test-Part A (PAST-A): a study with recently and non-recently divorced adults

Past research has demonstrated that divorced adults show more health problems and psychological distress than married adults. Considering the high prevalence rates of divorce among Western countries, new and robust measures should be developed to measure psychological distress after this specific transition in adulthood. The aim of this study was to adapt and validate a Portuguese version of the Psychological Adjustment to Separation Test-Part A (PAST-A; Sweeper and Halford in J Family Psychol 20(4):632–640, 2006). PAST-A is a self-report measure that assesses two key dimensions of separation adjustment problems: lonely-negativity and former partner attachment. Psychometric properties of the Portuguese version of PAST-A were assessed in terms of factor structure, internal consistency, and convergent and divergent validity, in an online convenience sample with divorced adults (N = 460). The PAST-A two-factor structure was confirmed by exploratory and confirmatory factor analyses, with each factor demonstrating very satisfactory internal consistency and good convergence. In terms of discriminant validity, the Portuguese PAST-A reveals a distinct factor from psychological growth after divorce. The results provided support for the use of the Portuguese PAST-A with divorced adults and also suggested that the explicative factors of the psychological adjustment to divorce may be cross-cultural stable. The non-existence of validated divorce-related well-being measures and its implications for divorce research are also discussed

Expanded geographic distribution and dietary strategies of the earliest Oldowan hominins and Paranthropus

The oldest Oldowan tool sites, ca. 2.6 million years ago (Ma), have previously been confined to Ethiopia’s Afar Triangle. We describe sites at Nyayanga, Kenya, dated to 3.032-2.581 Ma, and expand this distribution by over 1300 km. Furthermore, we found two hippopotamid butchery sites associated with mosaic vegetation and a C4 grazer-dominated fauna. Tool flaking proficiency was comparable to younger Oldowan assemblages, but pounding activities were more common. Tool use-wear and bone damage indicate plant and animal tissue processing. Paranthropus sp. teeth, the first from southwestern Kenya, possessed carbon isotopic values indicative of a diet rich in C4 foods. We argue that the earliest Oldowan was more widespread than previously known, used to process diverse foods including megafauna, and associated with Paranthropus from its onset