GaAs/Al 0.8 Ga 0.2 As avalanche photodiodes for soft X-ray spectroscopy

The soft X-ray spectroscopic performance of a GaAs/Al 0.8 Ga 0.2 As Separate Absorption and Multiplication (SAM) APD was assessed at room temperature using a 55 Fe source. An energy resolution of 1.08 keV (FWHM) was achieved for the 5.9 keV X-rays, at an avalanche gain of 3.5. The avalanche gain also improved the minimum detectable energy from 4.8 keV at unity gain to about 1.5 keV at a gain of 5. Through avalanche statistics analyses, we confirmed that (i) the APD’s FWHM was degraded by X-ray photon absorption within the avalanche region, and (ii) photon absorption in/near the n-cladding layer contributed to an undesirable secondary peak in the spectrum

Integrating radio-over-fiber communication system and BOTDR sensor system

In this paper, we propose and experimentally demonstrate for the first time, the integration of a radio-over-fiber (RoF) communication system and a Brillouin optical time-domain reflectometry (BOTDR) distributed sensor system using a single optical fiber link. In this proof-of-concept integrated system, the communication system is composed of three modulation formats of quadrature phase-shift keying (QPSK), 16-quadrature amplitude modulation (16-QAM) and 64-QAM, which are modulated onto an orthogonal frequency division multiplexing (OFDM) signal. Whereas, the BOTDR sensor system is used for strain and/or temperature monitoring over the fiber distance with a spatial resolution of 5 m using a 25 km single-mode silica fiber. The error vector magnitude (EVM) is analyzed in three modulation formats in the presence of various BOTDR input pump powers. Using QPSK modulation, optimized 18 dBm sensing and 10 dBm data power, the measured EVM values with and without bandpass filter are 3.5% and 14.5%, respectively. The proposed system demonstrates a low temperature measurement error (±0.49 °C at the end of 25 km) and acceptable EVM values, which were within the 3GPP requirements. The proposed integrated system can be effectively applied for practical applications, which significantly reduces the fiber infrastructure cost by effective usage of a single optical fiber lin

ʻĀina (land) as a leader: A scoping review of contemporary native Hawaiian literature

Culture frames individual and community well-being. Among Kānaka ʻŌiwi, or the Native people of Hawaiʻi, ʻāina (land) is a significant pillar of culture and community. Like other Indigenous peoples, Kānaka share a profound connection with ʻāina. With the root word ʻai (to eat), ʻāina directly translates to that which feeds. Throughout this paper, ʻāina encompasses land, ocean, water, sky, and natural resources – primary sources of nourishment, healing, learning, and identity for all Kānaka. ʻĀina and leadership are interconnected in Native Hawaiian worldview, but the complexity of this relationship is not clearly defined in existing literature. Thus, this scoping review explored the ways ʻāina exemplifies leadership. Five themes emerged, with implications for Kānaka well-being. ʻĀina as elder, healer, educator, and role model embodies leadership. Together, these themes indicate that Kānaka well-being is interdependent with ʻāina leadership. For community psychologists working on a global scale, it will be important for ʻāina leadership to be recognized in social justice initiatives with Kānaka ʻŌiwi, and potentially with other Indigenous and Pacific peoples.

Monocarboxylate transporter 2 (MCT2) as putative biomarker in prostate cancer

INTRODUCTION: Monocarboxylate transporter 2 (MCT2) is a transmembrane protein involved in the transport of monocarboxylates such as pyruvate and lactate. In a previous study we described overexpression of MCT2 in prostate carcinoma raising the hypothesis of using MCT2 as a possible biomarker in prostate cancer. With the present study we aimed to compare the pattern of expression of MCT2 and alpha-methylacyl-CoA racemase (AMACR), in prostate carcinoma, PIN lesions, non-neoplastic prostate tissue, and normal prostate and compare their sensitivity and specificity. Also, we wanted to evaluate the value of using MCT2 in combination with AMACR and the negative markers 34βE12 or p63 to detect prostate cancer. METHODS: A total of 349 cases, including prostate carcinoma, non-neoplastic prostate tissue and PIN lesions, from radical prostatectomies were examined by immunohistochemistry for AMACR, MCT2, p63, and 34βE12, using tissue microarrays (TMAs). Normal prostate from radical cystoprostatectomy was also studied. RESULTS: Our study revealed that MCT2, similarly to AMACR, was consistently expressed in prostate cancer regardless of the Gleason score. In combination with AMACR and p63 or 34βE12, MCT2 helped to improve the diagnosis of prostate carcinoma. Also, overexpression of MCT2 as well as AMACR in PIN lesions may indicate the involvement of these two proteins in prostate cancer initiation. CONCLUSIONS: We provided evidence for the presence of MCT2 in prostate cancer, selectively labeling malignant glands. Importantly, assessment of MCT2 together with AMACR, along with the negative markers, highly increases the accuracy in prostate cancer diagnosis.This work was supported by the FCT grant ref.PTDC/SAUMET/113415/2009 under the scope of ‘Programa Operacional Tematico Factores de Competitividade’’ (COMPETE) of ‘‘Quadro Comunitario de Apoio III’’ and co-financed by ‘‘Fundo Comunitario Europeu’’ FEDER. N.P.G. received fellowship from the Portuguese Foundation for Science and Technology (FCT), ref. FRH/BD/61027/2009

Al0.52In0.48P avalanche photodiodes for soft X-ray spectroscopy

The performance of Al0.52In0.48P avalanche photodiodes was assessed as soft X-ray detectors at room temperature. The effect of the avalanche gain improved the energy resolution and an energy resolution (FWHM) of 682 eV is reported for 5.9 keV X-rays

InAs avalanche photodiodes as X-ray detectors

We designed and demonstrated an InAs avalanche photodiode (APD) for X-ray detection, combining narrow band gap semiconductor materials and avalanche gain from APDs. The InAs APD (cooled by liquid nitrogen) was tested with a 55Fe X-ray source. Full width at half maximum (FWHM) from the spectra decreases rapidly with reverse bias, rising again for higher voltages, resulting in a minimum FWHM value of 401 eV at 5.9 keV. This minimum value was achieved at 10 V reverse bias, which corresponds to an avalanche gain of 11. The dependence of FWHM on reverse bias observed is explained by the competition between various factors, such as leakage current, capacitance and avalanche gain from the APD, as well as measurement system noise. The minimum FWHM achieved is largely dominated by the measurement system noise and APD leakage current

Game theory of mind

This paper introduces a model of ‘theory of mind’, namely, how we represent the intentions and goals of others to optimise our mutual interactions. We draw on ideas from optimum control and game theory to provide a ‘game theory of mind’. First, we consider the representations of goals in terms of value functions that are prescribed by utility or rewards. Critically, the joint value functions and ensuing behaviour are optimised recursively, under the assumption that I represent your value function, your representation of mine, your representation of my representation of yours, and so on ad infinitum. However, if we assume that the degree of recursion is bounded, then players need to estimate the opponent's degree of recursion (i.e., sophistication) to respond optimally. This induces a problem of inferring the opponent's sophistication, given behavioural exchanges. We show it is possible to deduce whether players make inferences about each other and quantify their sophistication on the basis of choices in sequential games. This rests on comparing generative models of choices with, and without, inference. Model comparison is demonstrated using simulated and real data from a ‘stag-hunt’. Finally, we note that exactly the same sophisticated behaviour can be achieved by optimising the utility function itself (through prosocial utility), producing unsophisticated but apparently altruistic agents. This may be relevant ethologically in hierarchal game theory and coevolution