Design of flexible ultrahigh-Q microcavities in diamond-based photonic crystal slabs

We design extremely flexible ultrahigh-Q diamond-based double-heterostructure photonic crystal slab cavities by modifying the refractive index of the diamond. The refractive index changes needed for ultrahigh-Q cavities with $Q ~ 10^7$, are well within what can be achieved ($\Delta n \sim 0.02$). The cavity modes have relatively small volumes $V<2 (\lambda /n)^3$, making them ideal for cavity quantum electro-dynamic applications. Importantly for realistic fabrication, our design is flexible because the range of parameters, cavity length and the index changes, that enables an ultrahigh-Q is quite broad. Furthermore as the index modification is post-processed, an efficient technique to generate cavities around defect centres is achievable, improving prospects for defect-tolerant quantum architectures.Comment: 9 pages, 4 figures (1 in colour

Propagation effects in optical waveguides, fibres and devices

This thesis consist of a theoretical study of propagation effects in optical waveguides, fibres and photonic crystals, with some comparison with experiment. ¶ ..

Influence of point cloud density on the results of automated Object-Based building extraction from ALS data

Ponencias, comunicaciones y pósters presentados en el 17th AGILE Conference on Geographic Information Science "Connecting a Digital Europe through Location and Place", celebrado en la Universitat Jaume I del 3 al 6 de junio de 2014.Nowadays there is a plethora of approaches dealing with object extraction from remote sensing data. Airborne Laser scanning (ALS) has become a new method for timely and accurate collection of spatial data in the form of point clouds which can vary in density from less than one point per square meter (ppsm) up to in excess of 200 ppsm. Many algorithms have been developed which provide solutions to object extraction from 3D data sources as ALS point clouds. This paper evaluates the influence of the spatial point density within the point cloud on the obtained results from a pre-developed Object-Based rule set which incorporates formalized knowledge for extraction of 2D building outlines. Analysis is performed with regards to the accuracy and completeness of the resultant extraction dataset. A pre-existing building footprint dataset representing Lake Tahoe (USA) was used for ground truthing. Point cloud datasets with varying densities (18, 16, 9, 7, 5, 2, 1 and 0.5ppsm) where used in the analysis process. Results indicate that using higher density point clouds increases the level of classification accuracy in terms of both completeness and correctness. As the density of points is lowered the accuracy of the results also decreases, although little difference is seen in the interval of 5-16ppsm

First-principles method for high-QQ photonic crystal cavity mode calculations

We present a first-principles method to compute radiation properties of ultra-high quality factor photonic crystal cavities. Our Frequency-domain Approach for Radiation (FAR) can compute the far-field radiation pattern and quality factor of cavity modes $\sim 100$ times more rapidly than conventional finite-difference time domain calculations. It also provides a simple rule for engineering the cavity's far-field radiation pattern

STRESS, DEPRESSION AND BURNOUT AMONG HOSPITAL PHYSICIANS IN RIJEKA, CROATIA

Background: Six years of recent ongoing economic and structural crisis in Croatia have brought to a significant decrease of socioeconomic standard in our country, and had an important impact on the health care system. In this background we examined the prevalence of depression and burnout and their association with work stressors. Subjects and methods: Cross sectional survey was conducted with self reported questionnaires in 459 hospital physicians in Rijeka, Croatia. Physicians were divided into three groups: surgical, nonsurgical and diagnostic group. Socio-demographic and work-related characteristics questionnaire, Occupational Stress Assessment Questionnaire (OSAQ), Maslach Burnout Inventory- Human Services Survey (MBI-HSS) and Beck Depression Inventory II (BDI-II) were used. Sperman correlation and logistic regression were calculated to rank association between stressors at work with depression and burnout syndrome. Results: Response rate was 62.3%, (286/459). Every fifth doctor experienced all examined stressors in the workplace as stressful. The prevalence of moderate and severe depression was 12.2%. High levels of emotional exhaustion were 43.6%, depersonalization 33.5%, and lack of personal accomplishment 49.1%. There was no statistical difference in surgical, nonsurgical and diagnostic groups in depression and all domains of MBI-HSS. Almost all stressors were correlated with depression and burnout syndrome. Most of the perceived stressors were significant predictors of burnout syndrome and depression. Conclusions: High levels of burnout domain compared to overall results from similar studies from other countries, placed the results in our sample on the higher end of the range, while results for depression after adjustment with lower cutoff point would be similar to those usually found in research literature. Our study showed that burnout is highly prevalent among Croatian physicians. Target interventions at the workplace should be considered as one of the strategies to reduce negative impact of work stress on physicians’ mental health

Rostromedial septal area controls pulsatile growth hormone release in the golden hamster

Limbic forebrain inhibits growth and growth hormone (GH) secretion in mature golden hamsters as shown by acceleration of growth and increases in serum GH concentrations following the electrolytic lesions of septum, transection of the hippocampus and surgical separation of these two regions. The growth-inhibitory function of this circuit is most probably mediated by somatostatinergic (SRIF) neurons. Such lesions induce hypoactivity possibly due to damage to endogenous opiatergic (EOP) neurons. EOP neurons facilitate spontaneous running in hamsters and mediate exercise-induced acceleration of growth and GH pulses. The coincidence of hypoactivity and growth acceleration after such lesions suggested the coexistence of SRIF and EOP fibers within the growth-inhibitory limbic forebrain circuit which control the rate of growth in mature hamsters by the variable inhibition of SRIF neurons by the EOP neurons. This hypothesis posits that accelerated growth is due to increased GH pulse frequency, and hypoactivity due to damage to EOP neurons, and was tested in this study by measuring pulsatile GH release (and as a measure of specificity, pulsatile prolactin release) in the presence and in the absence of opiate-receptor blocker naloxone in 21 female hamsters which sustained electrocoagulative lesions of rostromedial septum and 30 hamsters subjected to control surgery. Lesions doubled GH but not PRL pulse frequency, neither of which was affected by naloxone. Results support the hypothesis that opiatergic neurons facilitate pulsatile GH release by inhibiting the action of somatostatin neurons.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26758/1/0000310.pd

Absence of weight regulation in exercising hamsters

Spontaneous activity on horizontal discs causes a permanent upward displacement of hamster weight, length, and, under some circumstances, percentage body fat. This phenomenon manifests itself through an immediate increase in the rate of weight gain, a disappearance of a preference for sunflower seeds, as well as in a delayed and gradual increase in food intake during and immediately following the activity period. A week after termination of spontaneous disc running normal regulation of body weight is reinstated and maintained at the new elevated weight level. These results suggest that some concomitant of spontaneous disc running in hamsters renders the weight-regulatory mechanisms inoperative.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22388/1/0000837.pd

Identification of the Regulatory Logic Controlling Salmonella Pathoadaptation by the SsrA-SsrB Two-Component System

Sequence data from the past decade has laid bare the significance of horizontal gene transfer in creating genetic diversity in the bacterial world. Regulatory evolution, in which non-coding DNA is mutated to create new regulatory nodes, also contributes to this diversity to allow niche adaptation and the evolution of pathogenesis. To survive in the host environment, Salmonella enterica uses a type III secretion system and effector proteins, which are activated by the SsrA-SsrB two-component system in response to the host environment. To better understand the phenomenon of regulatory evolution in S. enterica, we defined the SsrB regulon and asked how this transcription factor interacts with the cis-regulatory region of target genes. Using ChIP-on-chip, cDNA hybridization, and comparative genomics analyses, we describe the SsrB-dependent regulon of ancestral and horizontally acquired genes. Further, we used a genetic screen and computational analyses integrating experimental data from S. enterica and sequence data from an orthologous regulatory system in the insect endosymbiont, Sodalis glossinidius, to identify the conserved yet flexible palindrome sequence that defines DNA recognition by SsrB. Mutational analysis of a representative promoter validated this palindrome as the minimal architecture needed for regulatory input by SsrB. These data provide a high-resolution map of a regulatory network and the underlying logic enabling pathogen adaptation to a host