Stability of quantum-dot excited-state laser emission under simultaneous ground-state perturbation

The impact of ground state amplification on the laser emission of In(Ga)As quantum dot excited state lasers is studied in time-resolved experiments. We find that a depopulation of the quantum dot ground state is followed by a drop in excited state lasing intensity. The magnitude of the drop is strongly dependent on the wavelength of the depletion pulse and the applied injection current. Numerical simulations based on laser rate equations reproduce the experimental results and explain the wavelength dependence by the different dynamics in lasing and non-lasing sub-ensembles within the inhomogeneously broadened quantum dots. At high injection levels, the observed response even upon perturbation of the lasing sub-ensemble is small and followed by a fast recovery, thus supporting the capacity of fast modulation in dual-state devices

Time-resolved amplified spontaneous emission in quantum dots

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 97, 251106 (2010) and may be found at https://doi.org/10.1063/1.3529447.In time-resolved experiments at InGaAs/GaAs quantum-dots-in-a-well (DWELL) semiconductor optical amplifiers, pump-probe of the ground state (GS) population, and complementary measurement of the amplified spontaneous emission of the excited state (ES) population, we are able to separate the early subpicosecond dephasing dynamics from the later picosecond population relaxation dynamics. We observe a 10 ps delay between the nonlinear GS pulse amplification and the subsequent ES population drop-off that supports the dominance of a direct two dimensional reservoir-GS capture relaxation path in electrically pumped quantum-dot-DWELL structures.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, Bauelement

Risk perception of arsenic exposure from rice intake in a UK population

In the UK, consumption of rice and rice-based products is on the rise but, notwithstanding public expressed concerns about such products as an exposure route for arsenic (e.g. BBC News report, 2017“Should I worry about arsenic in my rice?”) there are few, if any published data on public perceptions of risks associated with exposure to arsenic in rice. We therefore aimed to determine the risk perception of arsenic exposure from rice intake and factors that are associated with arsenic knowledge and whether or not this knowledge had an influence on rice consumption and cooking practices. A questionnaire, targeting participation of rice-eating ethnic minorities in Greater Manchester, UK, was administered to 184 participants. A multivariate generalized linear model was used to determine the factors associated with rice consumption behaviour, cooking practices, and risk perception. We show for the first time that the general population did not associate arsenic, which they perceive as toxic to health, with rice consumption. More than half of the participants knew about arsenic as a hazardous substance but less than ten percent knew that rice consumption could be an important route of arsenic exposure. Knowledge of arsenic was significantly lower in Asian/Asian British:Pakistanis (Pakistani) (OR: 0.006; 95% CI:0.00-0.03) and Asian/Asian British:Bangladeshis (Bangladeshi) (OR: 0.064; 95% CI:0.01-0.25) compared to White:English/Welsh/Scottish/Northern Irish/British (White British). Moreover, Bangladeshis consumed three times more rice (OR: 2.92; 95% CI:1.73-4.93) compared to White British. Overall higher rice consumption was not associated with higher knowledge of the nutritional value of rice. Rinsing rice before cooking, an effective arsenic removal technique, was practised by 93% of the participants, however the most popular cooking method was the use of adequate water (rice to water ratio of 1:2) but not excess water (rice to water ratio of > 1:4), the latter being more effective in removing arsenic. Better education, higher weekly expenditure on food and prior knowledge of arsenic hazard were all significant factors positively influencing a change in behaviour to reduce arsenic exposure from rice intake

Archaeogenetic analysis of Neolithic sheep from Anatolia suggests a complex demographic history since domestication

Sheep were among the first domesticated animals, but their demographic history is little understood. Here we analyzed nuclear polymorphism and mitochondrial data (mtDNA) from ancient central and west Anatolian sheep dating from Epipaleolithic to late Neolithic, comparatively with modern-day breeds and central Asian Neolithic/Bronze Age sheep (OBI). Analyzing ancient nuclear data, we found that Anatolian Neolithic sheep (ANS) are genetically closest to present-day European breeds relative to Asian breeds, a conclusion supported by mtDNA haplogroup frequencies. In contrast, OBI showed higher genetic affinity to present-day Asian breeds. These results suggest that the east-west genetic structure observed in present-day breeds had already emerged by 6000 BCE, hinting at multiple sheep domestication episodes or early wild introgression in southwest Asia. Furthermore, we found that ANS are genetically distinct from all modern breeds. Our results suggest that European and Anatolian domestic sheep gene pools have been strongly remolded since the Neolithic

From gut dysbiosis to altered brain function and mental illness: mechanisms and pathways

The human body hosts an enormous abundance and diversity of microbes, which perform a range of essential and beneficial functions. Our appreciation of the importance of these microbial communities to many aspects of human physiology has grown dramatically in recent years. We know, for example, that animals raised in a germ-free environment exhibit substantially altered immune and metabolic function, while the disruption of commensal microbiota in humans is associated with the development of a growing number of diseases. Evidence is now emerging that, through interactions with the gut-brain axis, the bidirectional communication system between the central nervous system and the gastrointestinal tract, the gut microbiome can also influence neural development, cognition and behaviour, with recent evidence that changes in behaviour alter gut microbiota composition, while modifications of the microbiome can induce depressive-like behaviours. Although an association between enteropathy and certain psychiatric conditions has long been recognized, it now appears that gut microbes represent direct mediators of psychopathology. Here, we examine roles of gut microbiome in shaping brain development and neurological function, and the mechanisms by which it can contribute to mental illness. Further, we discuss how the insight provided by this new and exciting field of research can inform care and provide a basis for the design of novel, microbiota-targeted, therapies.GB Rogers, DJ Keating, RL Young, M-L Wong, J Licinio, and S Wesseling

The effect of nonconformities encountered in the use of technology on the occurrence of collision, contact and grounding accidents

Technology and its innovative applications make life easier and reduce the workload on seafarers. Today's ship bridges have much more modern and integrated navigation systems than before, and the ship's handling and management have become much easier. However, nonconformities encountered in the use of technological devices may cause accidents. In this study, the effect of human factor related errors associated with the use of the bridge's electronic navigational devices on grounding and collision-contact accidents was investigated. Nonconformities obtained from 175 collision-contact and 115 grounding accident reports were qualitatively analysed by means of human factor analysis and a classification system. Afterwards, relationships between nonconformities and their probabilities were evaluated quantitatively via a Bayesian network method. As a result of the study, the accident network was revealed. This accident network summarizes how operating errors in the use of technological equipment cause accidents. Recommendations on the prevention of accidents caused by operating errors associated with the use of new technologies are finally given

Proximal tibiofibular synostosis

A 22-year-old male patient admitted to our clinic with mild pain in left knee. Pain had started 10 years ago and there was no history of trauma. Pain was increased with kneeling. No abnormality was detected on physical examination. Imaging results revealed proximal tibiofibular synostosis in left knee

Using augmented reality to teach fifth grade students about electrical circuits

Augmented reality technology has recently become one of the primary technologies for science education. Although augmented reality is attractive, a need exists for good content, implementation, and evaluations, as in every technology integration process. To this end, this study aims to develop and evaluate an augmented reality application to teach fifth grade students about electrical currents. For this purpose, students' attitudes toward augmented reality applications and science and technology courses were examined using two course designs. In the first design, the students were taught an augmented reality assisted electrical circuit lesson in a group, while, in the second design, the students studied individually. The attitudes of the students studying individually toward the augmented reality applications were significantly higher than the students studying in a group. However, no significant differences existed in the students' attitudes toward science and technology courses. Class observations and teacher interviews provided details about the classroom implications of augmented reality

Early results of non-fusion dynamic stabilization with InterS

WOS: 000290235800004Aim. The current study aims to investigate the early out comes of the new technique applied to degenerative spinal disc disease (DSDD) patients. For this purpose 25 patients having DSDD, spinal stenosis and spondilolisthesis were included in the study. The treatments were performed on a two-stage procedure, first surgically with laminectomy, discectomy (when needed) and then the low invasive non-fusion dynamic stabilization with InterS. Methods. The outcomes of the procedure has been followed up for 12 months. Patients were followed up by means of clinical and radiographic techniques. All of the three group of patients underwent a midline decompressive laminectomy with foraminotomies at the effected levels. Furthermore, in lumbar disc hernia cases, discectomy was performed. Oswestry pain scale was used for the clinical evaluation. Results. The study included patients from both sexes (16 females, 9 males) with a mean age of 54.45 years (range 37-68). Symptoms and signs included pain (100), 15 patients have DDD, 7 patients have spinal stenosis, 3 patients spondylolisthesis. Localization was as follows: L3-4: 5 (20%), L4-5: 20 (80%). Satisfactory results were demonstrated in 21 (84%) patients. The average of Oswestry scores was 42.15 in the preoperative period and 8.8 in the postoperative period. Conclusion. Non-fusion dynamic stabilization method of InterS type is a safe procedure. We believe this technique may reduce higher complication rates for patients with spinal stenosis and spondylolysthesis, degenerative disc disease. Motion preservation, early mobilization, short hospital stays and shorter recovery are the main advantages of the operation