Excess noise measurement in In0.53Ga0.47As

The excess noise due to impact ionization has been measured explicitly for the first time in In/sub 0.53/Ga/sub 0.47/As. By using a phase sensitive detection technique, the noise due to avalanche current was determined even in the presence of high tunneling currents. The excess noise due to pure electron injection measured on a series of thick In/sub 0.53/Ga/sub 0.47/As p/sup +/-i-n/sup +/ diodes suggests large electron to hole ionization coefficient ratio between 3.7 at electric field of 310 kV/spl middot/cm/sup -1/ to 5.3 at 260 kV/spl middot/cm/sup -1/. Excess noise was also measured at fields as low as 155 kV/spl middot/cm/sup -1/ suggesting that significant impact ionization occurs at these low fields. The multiplication and excess noise calculated using published ionization coefficients and ignoring dead space effects, gave good agreement with the experimental data for mixed and pure electron injection

A theoretical comparison of the breakdown behavior of In0.52Al0.48As and InP near-infrared single-photon avalanche photodiodes

We study the breakdown characteristics and timing statistics of InP and In0.52Al0.48As single-photon avalanche photodiodes (SPADs) with avalanche widths ranging from 0.2 to 1.0 mu m at room temperature using a random ionization path-length model. Our results show that, for a given avalanche width, the breakdown probability of In0.52Al0.48As SPADs increases faster with overbias than InP SPADs. When we compared their timing statistics, we observed that, for a given breakdown probability, InP requires a shorter time to reach breakdown and exhibits a smaller timing jitter than In0.52Al0.48As. However, due to the lower dark count probability and faster rise in breakdown probability with overbias, In0.52Al0.48As SPADs with avalanche widths <= 0.5 mu m are more suitable for single-photon detection at telecommunication wavelengths than InP SPADs. Moreover, we predict that, in InP SPADs with avalanche widths <= 0.3 mu m and In0.52Al0.48As SPADs with avalanche widths <= 0.2 mu m, the dark count probability is higher than the photon count probability for all applied biases

Innocence and Guilt Detection in High-Stakes Television Appeals

The present thesis explored the cognitive and affective mechanisms underlying the cues used to make innocence-guilt decisions in the high-stakes situation of television appeals in which people appeal publicly for the return of a loved one. Two aspects of the processes involved in making judgements of veracity were studied. Part 2 examined the interaction between explicit and implicit judgments. The studies in Part 2 experimentally manipulated aspects of 12 appeals to test hypotheses about the heuristics judges used to determine veracity. The hypotheses in these studies were initially based on the central assumption that in the absence of unambiguous information judges will draw on heuristics to make veracity judgments. These cognitive shortcuts were hypothesised to lead to biases in innocence-guilt judgments. The innocence bias was introduced as a potential predisposition that stood to be tested. Results did not reveal a consistent innocence or guilt bias. Rather, while all four experiments in Part 2 indicated the presence of different underlying cognitive processes across all experimental conditions, the results from these studies would appear to challenge the existence of any intrinsic tendency towards biases. In Part 3, the context of the appeals was taken as the basis for the assumption that truthful people would give clearer indications of grief than ones who were lying. Multivariate cues were analysed simultaneously using 39 appeals, with a theoretical basis drawn from the grief literature. Eight previously unidentified aspects consisting of verbal cues drawn from grief literature are found to distinguish honest and deceptive appeals with high accuracy and reliability. The work thus contributed to the initial understanding of the interaction between explicit and implicit decisions in making innocence-guilt judgments. Standing models of cognitive processing and their implications for the present thesis were also discussed. Contingent upon further clarification of cognitive processes involved during innocence and guilt verdict decision-making, the findings are particularly germane to the area of televised press conferences and have implications for police and practice

Application of SCOPE-C to measure social inclusion among mental health services users in Hong Kong

This study describes the construction of the Chinese version of the Social and Communities Opportunities Profile (SCOPE), henceforth, the SCOPE-C, to measure social inclusion among mental health services users in Hong Kong. The SCOPE-C was developed based on concept-mapping and benchmarking of census questions. The questionnaire consisted of 56 items, went through a standardized linguistic validation process and was pilot tested with qualitative feedback from five users of mental health services. Altogether 168 Chinese service users were recruited through various NGO mental health services to have three times face-to-face interview between October 2013 and July 2014. Results indicated that items related to satisfaction with opportunities and perceived opportunities in various social domains had high consistency. Nearly all the Kappa statistics and Pearson correlation coefficients between the baseline and two rounds of re-test were significant. The SCOPE-C was considered a valid instrument for Hong Kong mental health user population

Co-infections of ectoparasite species in synanthropic rodents of western Sarawak, Malaysian Borneo

Little is known regarding infestation of ectoparasites in synanthropic rodents in Sarawak, Malaysia. A total of 44 rodents from three species (Rattus rattus, Rattus tiomanicus and Sundamys muelleri) were trapped from four residential areas in western Sarawak, Malaysia, for ectoparasites screening. A total of 117 ectoparasites from three hard tick species (Ixodes granulatus, Haemaphysalis sp. 1, Haemaphysalis sp. 2), three mesostigmatid mite species (Laelaps echidninus, Laelaps sedlaceki, and Laelaps nuttalli), one trombiculid mite (chigger species), and one louse species (Hoplopleura sp.), were recovered from 32 infected rodents (72.73% infestation). Infestations by multiple ectoparasite species on the same rodent individuals were recorded in R. rattus and R. tiomanicus (28.1%, n=9) in this study, while Sundamys muelleri was only infested with L. echidninus. One R. rattus individual was co-infected with ticks, louse, and mesostigmatid mite. L. echidninus was the generalist ectoparasite species that infected all three rodent species in three of the residential areas studied. Ectoparasite species diversity was significantly different among four residential areas based on Shannon index and diversity t-test (p-value <0.05). This study provides the first record of the association of synanthropic rodents with multiple ectoparasite infections in residential areas of western Sarawak, Malaysia

"quasi-particles" in bosonization theory of interacting fermion liquids at arbitrary dimensions

Within bosonization theory we introduce in this paper a new definition of "quasi-particles" for interacting fermions at arbitrary space dimenions. In dimensions higher than one we show that the constructed quasi-particles are consistent with quasi-particle descriptions in Landau Fermi liquid theory whereas in one-dimension the quasi-particles" are non-perturbative objects (spinons and holons) obeying fractional statistics. The more general situation of Fermi liquids with singular Landau interaction is discussed.Comment: 10 page

Current studies into the genotoxic effects of nanomaterials

10.4061/2010/947859Journal of Nucleic Acids2010

Selective deletion of PPARβ/δ in fibroblasts causes dermal fibrosis by attenuated LRG1 expression.

Connective tissue diseases of the skin are characterized by excessive collagen deposition in the skin and internal organs. Fibroblasts play a pivotal role in the clinical presentation of these conditions. Nuclear receptor peroxisome-proliferator activated receptors (PPARs) are therapeutic targets for dermal fibrosis, but the contribution of the different PPAR subtypes are poorly understood. Particularly, the role of fibroblast PPARβ/δ in dermal fibrosis has not been elucidated. Thus, we generated a mouse strain with selective deletion of PPARβ/δ in the fibroblast (FSPCre- &lt;i&gt;Pparb/d&lt;/i&gt; &lt;sup&gt;-/-&lt;/sup&gt; ) and interrogated its epidermal and dermal transcriptome profiles. We uncovered a downregulated gene, leucine-rich alpha-2-glycoprotein-1 ( &lt;i&gt;Lrg1&lt;/i&gt; ), of previously unknown function in skin development and architecture. Our findings suggest that the regulation of &lt;i&gt;Lrg1&lt;/i&gt; by PPARβ/δ in fibroblasts is an important signaling conduit integrating PPARβ/δ and TGFβ1-signaling networks in skin health and disease. Thus, the FSPCre- &lt;i&gt;Pparb/d&lt;/i&gt; &lt;sup&gt;-/-&lt;/sup&gt; mouse model could serve as a novel tool in the current gunnery of animal models to better understand dermal fibrosis

Improved Optoelectronic Properties of Rapid Thermally Annealed Dilute Nitride GaInNAs Photodetectors

We investigate the optical and electrical characteristics of GaInNAs/GaAs long-wavelength photodiodes grown under varying conditions by molecular beam epitaxy and subjected to postgrowth rapid thermal annealing (RTA) at a series of temperatures. It is found that the device performance of the nonoptimally grown GaInNAs p-i-n structures, with nominal compositions of 10% In and 3.8% N, can be improved significantly by the RTA treatment to match that of optimally grown structures. The optimally annealed devices exhibit overall improvement in optical and electrical characteristics, including increased photoluminescence brightness, reduced density of deep-level traps, reduced series resistance resulting from the GaAs/GaInNAs heterointerface, lower dark current, and significantly lower background doping density, all of which can be attributed to the reduced structural disorder in the GaInNAs alloy.© 2012 TMS