Survive the climate variability?

I-Ching Chen,Sheng-Feng Shen,Shih-Fan Chan 한국응용곤충학회 2013 한국응용곤충학회 학술대회논문집 Vol.2013 No.10

Climate and its variability characterize abiotic environment for species on the earth. Increased seasonality in higher latitude and/or pronounced diurnal temperate range in higher ground as well as decreasing mean temperature are major climate gradients to which organisms must adapt through physiological and behavioral plasticity. IPCC AR5 pointed out that climate variability and its regional behavior remain top concerns, which may well pose great challenges to climate change biology. We use Nicrophorus nepalensis (Coleoptera: Silphidae) a wide-distributed burying beetle in low latitude Asia as model species to investigate possible impacts of climate variability on species performance. N. nepalensis is a scavenging species exploring carcasses for feeding and reproduction. To consider their breeding performance, we baited N. nepalensis by small mouse carcasses and measured the rate at which they successfully buried the carcasses into soil. We look at climate variability along elevational gradients of intact forest and open habitats exposure to agricultural activities. The probability of successful breeding is higher in intact forest than that in open habitat with unimodal fashion of peak at 1800m. We found that local climate variability, more specifically, the diurnal temperature range (DTR), impedes successful breeding of N. nepalensis. Despite variable environmental conditions associated with habitat opening, such as increased soil density, reduced leaf litter amount and relative humidity, enlarged DTR seems to be the principal cause of failure. The negative effects of greater DTR on breeding success were confirmed by laboratory experiments. DTR remains stable in primary forests, in contrast to its increase in more disrupted habitats along the same transect. Reducing vegetation cover exposes mountains to radiant heating, a trend with significant elevational effect, resulting in large DTR in high lands. Although N. nepalensis is widely distributed in the mountain areas, non-forest patches support only part of their life cycle, different function groups to support decomposition process at open habitats are expected. Climate change and habitat degradation are among the major drivers of biodiversity loss. Our study highlights land-use and land-cover change (LULCC) in altering local temperature variability and reinforces the concern of its interplay with climate change.

Numerical Simulation of High Power LED Heat-Dissipating System

Shih-Jeh Wu,Hsiang-Chen Hsu,Shen-Li Fu,Jiam-Nan Yeh 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.2

In this paper, thermal analysis of the heat dissipation under different heat sink for high-power white Light Emitting Diode (LED) is presented. Junction temperature of LED is elevated as the power of LED increases, which brings up deterioration of light efficiency and other side effects. Heat dissipation is another design concern other than material and illumination efficiency. The purpose of this paper is to investigate the cooling of high-power LED chips and modules for design of heat sinks. Three types of heat sinks are designed for a tandem 12-chip module and an extensive numerical investigation of the heat sink design performance is conducted by Computational Fluid Dynamics software Fluent. The effects of heat sink geometry and adhesive material are also investigated. Design variables are the thickness of sink base, number, thickness and length of fins. The total wetted area is the dominant factor to the junction temperature. The objective of design regarding the junction temperatures around 50°C is easily achieved. However, its effect is limited at high values of these parameters, furthermore an excessive number of fins incurs reverse consequence due to problem of ventilation also waste of material.

Bidirectional Hybrid DWDM-PON for HDTV/Gigabit Ethernet/CATV Applications

Hai-Han Lu,Wen-Shing Tsai,Tzu-Shen Chien,Shih-Hung Chen,Yu-Chieh Chi,Che-Wei Liao 한국전자통신연구원 2007 ETRI Journal Vol.29 No.2

A new scheme for bi-directional HDTV/Gigabit Ethernet/CATV transmission over a hybrid densewavelength- division-multiplexing passive optical network (DWDM-PON) is proposed and demonstrated. It is based on injection-locked vertical-cavity surface-emitting lasers and distributed-feedback laser diodes as transmitters. Services with 129 HDTV channels, a 1.25 Gbps Gigabit Ethernet connection, and 77 CATV channels are successfully demonstrated over 40 km single-mode fiber links. Good performance of bit error rate, carrier-to-noise ratio, composite second order, and composite triple beat is achieved in our proposed bidirectional DWDM-PON.

The Optimal Government Shareholding Strategy and the Cost Structure

Chin-Shu Huang,Jen-Yao Lee,Shih-Shen Chen 서울대학교 경제연구소 2006 Seoul journal of economics Vol.19 No.2

This paper analyzes government's optimal shareholding strategy within the framework of the mixed oligopoly. It is found that: (1) When both public and domestic firms have the same cost coefficient, the government's best policy is to adopt the full mixed oligopoly. (2) When the cost coefficient of the public firm is lower than a threshold value, the government should opt for a full mixed-oligopoly policy. However, when the public firm's cost coefficient is higher than the threshold value, the government should privatize the public firm completely and exit the market. The single mixed oligopoly is just an alternative proposal when it falls to transform all of the private firms into mixed ownership enterprises.

Comprehensive profiles and diagnostic value of menopausal-specific gut microbiota in premenopausal breast cancer

Hou Ming-Feng,Ou-Yang Fu,Li Chung-Liang,Chen Fang-Ming,Chuang Chieh-Han,Kan Jung-Yu,Wu Cheng-Che,Shih Shen-Liang,Shiau Jun-Ping,Kao Li-Chun,Kao Chieh-Ni,Lee Yi-Chen,Moi Sin-Hua,Yeh Yao-Tsung,Cheng Chi 생화학분자생물학회 2021 Experimental and molecular medicine Vol.53 No.-

In Western countries, breast cancer tends to occur in older postmenopausal women. However, in Asian countries, the proportion of younger premenopausal breast cancer patients is increasing. Increasing evidence suggests that the gut microbiota plays a critical role in breast cancer. However, studies on the gut microbiota in the context of breast cancer have mainly focused on postmenopausal breast cancer. Little is known about the gut microbiota in the context of premenopausal breast cancer. This study aimed to comprehensively explore the gut microbial profiles, diagnostic value, and functional pathways in premenopausal breast cancer patients. Here, we analyzed 267 breast cancer patients with different menopausal statuses and age-matched female controls. The α-diversity was significantly reduced in premenopausal breast cancer patients, and the β-diversity differed significantly between breast cancer patients and controls. By performing multiple analyses and classification, 14 microbial markers were identified in the different menopausal statuses of breast cancer. Bacteroides fragilis was specifically found in young women of premenopausal statuses and Klebsiella pneumoniae in older women of postmenopausal statuses. In addition, menopausal-specific microbial markers could exhibit excellent discriminatory ability in distinguishing breast cancer patients from controls. Finally, the functional pathways differed between breast cancer patients and controls. Our findings provide the first evidence that the gut microbiota in premenopausal breast cancer patients differs from that in postmenopausal breast cancer patients and shed light on menopausal-specific microbial markers for diagnosis and investigation, ultimately providing a noninvasive approach for breast cancer detection and a novel strategy for preventing premenopausal breast cancer.