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Search Results: 1 - 10 of 190575 matches for " G. Koh "
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Assessing the Efficacy of Two Indirect Methods for Quantifying Canopy Variables Associated with the Interception Loss of Rainfall in Temperate Hardwood Forests  [PDF]
Thomas G. Pypker, Catherine S. Tarasoff, Hong-Suk Koh
Open Journal of Modern Hydrology (OJMH) , 2012, DOI: 10.4236/ojmh.2012.22005
Abstract: Forest canopy water storage (S), direct throughfall fraction (p) and mean evaporation rate to mean rainfall intensity ratio (E/R) vary between storms and seasonally. Typically, researchers only quantify the mean growing and dormant season values of S, p and E/R for deciduous forests, thereby ignoring seasonal changes S, p and E/R .Past researchers adapted the mean method, which is usually used to estimate S, p and E/R on an annual or seasonal basis, to estimate the same canopy variables on a per storm basis (individual storm (IS) method). The disadvantage of the IS method is that it requires more expensive equipment and the calculation of the canopy variables is more labor intensive relative to the mean method. The goal of this study was to explore the use of the IS method for northern hardwood forests and to determine whether estimates of S, p and E/R derived by the IS method produce more accurate estimates of rainfall interception loss (In) using the Gash model relative to estimates derived by the mean method. The IS method estimated that S increased from approximately 0.11 mm in the early spring to 1.2 mm in the summer and then declined to 0.24 mm after fall senescence. Direct throughfall decreased from 0.4 in the early spring to 0.11 in the summer, and then increased to 0.4 after leaf senescence. When measurement period estimates of p, S and E/R derived by the IS and mean methods were applied to the Gash model, the modeled estimates of In differed from the measured values by 14.0 mm and 1.3 mm, respectively. Therefore, because the mean method provided more accurate estimates of In, the extra effort and expense required by the IS method is not advantageous for studies in northern hardwood forests that only need to model annual or seasonal estimates of In.
Square Root Singularity in Boundary Reflection Matrix
J. D. Kim,I. G. Koh
Physics , 1996, DOI: 10.1016/S0370-2693(96)01185-9
Abstract: Two-particle scattering amplitudes for integrable relativistic quantum field theory in 1+1 dimensions can normally have at most singularities of poles and zeros along the imaginary axis in the complex rapidity plane. It has been supposed that single particle amplitudes of the exact boundary reflection matrix exhibit the same structure. In this paper, single particle amplitudes of the exact boundary reflection matrix corresponding to the Neumann boundary condition for affine Toda field theory associated with twisted affine algebras $a_{2n}^{(2)}$ are conjectured, based on one-loop result, as having a new kind of square root singularity.
Two-Way but Asymmetrical Reproductive Interference between an Invasive Veronica Species and a Native Congener  [PDF]
Koh-Ichi Takakura
American Journal of Plant Sciences (AJPS) , 2013, DOI: 10.4236/ajps.2013.43069
Abstract:

Recent studies have suggested that reproductive interference, a deleterious interspecific interaction in the mating process, plays an important role in biological invasions. In the system of plant species, however, the border with the pollen limitation has often been vague in past studies. This study, using field and laboratory experiments and field observations, examined the reproductive success of an endangered native herbaceous plant, Veronica polita lilacina, in the context of the reproductive interference by the alien congener, V. persica. The auto-pollination experiment confirmed that both species can usually produce seeds even without external conspecific pollens. Results of the artificial pollination experiment demonstrated that pollination with the heterospecific pollens significantly decreases the number of seeds in the native species, but not in the alien species. A transplant experiment revealed that the coexistence with the alien species reduced the fruiting success of the native species. Field observations have shown the interaction between two species in the native patch with only one intruding alien species. They demonstrated that native individuals placed closer to the alien individual suffered a greater decrease in fruiting success and the seed production and that the alien intruder produced no seed. These results demonstrate that species that could reproduce via the auto-pollination suffered the reproductive interference and that the native species also exert the resistive reproductive interference slightly. These interactions can explain the displacement pattern of the native species by the alien congener in Japan.

Rectal Lymphoma: A Diagnostic Challenge  [PDF]
Koh Ging Wong
Open Journal of Gastroenterology (OJGas) , 2015, DOI: 10.4236/ojgas.2015.54004
Abstract: Rectal lymphoma is a rare colorectal tumor with incidence of 0.2% - 0.6%. We report a rare case of large rectal lymphoma. Our patient is a 48-year-old man, presented with 2 months history of per rectal bleed, altered bowel habits and weight loss. Clinical examination, computed tomography scan and initial endoscopic mucosal biopsy were indistinguishable from Rectal Carcinoma. With high level of suspicion, we resorted to full thickness punch biopsy in lithotomy position for a good tissue sample. Ultimately, an immunohistochemical study confirmed Diffuse Large B-cells Lymphoma (DLBCL). This case highlighted the importance of high level of suspicion for lymphoma when dealing with a rectal tumor. Accurate diagnosis of rectal lymphoma affects the treatment modalities and prognosis of the patient.
Current Situations and Challenges Concerning Sexual Health among Unmarried Couples Composed of a Mix of Japanese, South Korean Nationals, and Ethnic Koreans Born in Japan (Zainichi): A Qualitative Study  [PDF]
Chie Koh, Hiroya Matsuo
Health (Health) , 2017, DOI: 10.4236/health.2017.91002
Abstract: South Korean nationals are heavily represented in Japan’s foreign population, making up around 20% of all foreign residents in the country. Koreans in Japan can be viewed in two groups: Korean nationals who work or study in Japan, and those of Korean ancestry who were born in Japan or otherwise have historical reasons for residency (commonly called zainichi). There are certain differences seen in gender roles and Confucianism-based traditional culture among Japanese, South Korean nationals, and zainichi. This qualitative study examined consciousness and attitudes about marriage, family planning, and work-life balance in unmarried couples among these three groups. Semi- structured interviews were conducted with five unmarried couples comprising two members from the above three groups (age range: 20 - 35 years), residing in the Kinki region of western Japan. Twelve categories, 25 subcategories, and 79 codes were extracted from 636 contexts. Values regarding sexual health were analyzed from four viewpoints: marriage, family planning, work-life ba- lance, and sexual concerns. The results showed that the couples thought positively about marriage and family planning, while they had several sources of anxiety related to Confucian values and problems stemming from their different nationalities/roots. It is possible that gender roles and Confucian beliefs affect their sexual health. The study underscores that health professionals should provide pertinent knowledge and skills about family planning and child rearing, as well as premarital sexual health counselling, for unmarried couples composed of Japanese, South Korean nationals, and zainichi.
Degradation of light emitting diodes: a proposed methodology

Sau Koh,Willem Van Driel,G Q Zhang,

半导体学报 , 2011,
Abstract: Due to their long lifetime and high efficacy, light emitting diodes have the potential to revolutionize the illumination industry. However, self heat and high environmental temperature which will lead to increased junction temperature and degradation due to electrical overstress can shorten the life of the light emitting diode. In this research, a methodology to investigate the degradation of the LED emitter has been proposed. The epoxy lens of the emitter can be modelled using simplified Eyring methods whereas an equation has been proposed for describing the degradation of the LED emitters.
Occupational health for an ageing workforce: do we need a geriatric perspective?
Gerald Koh, David Koh
Journal of Occupational Medicine and Toxicology , 2006, DOI: 10.1186/1745-6673-1-8
Abstract: The world is undergoing unprecedented ageing and in many developed countries, the workforce is contracting due to falling birthrates, longer life expectancies and changing population demographics [1]. Experts have warned that if society continues to reduce the number of people over the age of 50 who are not actively working, economies will suffer a cumulative annual loss of GDP [2]. Some countries like the UK are already introducing anti-age discrimination policies laws and retirement ages are projected to increase in the coming years [3]. Employers now have to face the prospect of having workers in their sixties. In New Zealand, the number of older persons aged 45 to 65 years is expected to increase from 35% to 45% within the working-age population between 2001 and 2051 [4]. The International Labour Organisation estimates that the number of economically active persons aged 65 years and above will increase from 83.2 million persons in the world in 2000 to 136 million persons by 2020 [5]. Occupational physicians are accustomed to managing middle-aged workers and their associated health problems but are we ready to manage elderly-related illnesses that may impact worker performance and health?Geriatrics is the branch of medicine that is devoted to the care of older people [6]. The relatively young discipline addresses the unique needs and circumstances of the elderly and is characterized by recognition of geriatric syndromes. Examples of conditions that affect the elderly include falls, impaired cognition, disability, malnutrition, incontinence and iatrogenesis. At first glance, most of these syndromes are associated with advanced age and it is unlikely that such an old person would still be working and hence be seen by an occupational physician. However, when one considers that many geriatric syndromes can present in fifth decade of life, it becomes apparent that knowledge of geriatric syndromes may be relevant to occupational health. This paper will use 2 common ger
Comprehensive Analysis of Transcript Start Sites in Ly49 Genes Reveals an Unexpected Relationship with Gene Function and a Lack Of Upstream Promoters
Frances Gays,Alan S. C. Koh,Katarzyna M. Mickiewicz,Jonathan G. Aust,Colin G. Brooks
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0018475
Abstract: Comprehensive analysis of the transcription start sites of the Ly49 genes of C57BL/6 mice using the oligo-capping 5′-RACE technique revealed that the genes encoding the “missing self” inhibitory receptors, Ly49A, C, G, and I, were transcribed from multiple broad regions in exon 1, in the intron1/exon2 region, and upstream of exon -1b. Ly49E was also transcribed in this manner, and uniquely showed a transcriptional shift from exon1 to exon 2 when NK cells were activated in vitro with IL2. Remarkably, a large proportion of Ly49E transcripts was then initiated from downstream of the translational start codon. By contrast, the genes encoding Ly49B and Q in myeloid cells, the activating Ly49D and H receptors in NK cells, and Ly49F in activated T cells, were predominantly transcribed from a conserved site in a pyrimidine-rich region upstream of exon 1. An ~200 bp fragment from upstream of the Ly49B start site displayed tissue-specific promoter activity in dendritic cell lines, but the corresponding upstream fragments from all other Ly49 genes lacked detectable tissue-specific promoter activity. In particular, none displayed any significant activity in a newly developed adult NK cell line that expressed multiple Ly49 receptors. Similarly, no promoter activity could be found in fragments upstream of intron1/exon2. Collectively, these findings reveal a previously unrecognized relationship between the pattern of transcription and the expression/function of Ly49 receptors, and indicate that transcription of the Ly49 genes expressed in lymphoid cells is achieved in a manner that does not require classical upstream promoters.
(E)-1-(1-Hydroxynaphthalen-2-yl)-3-(2,4,5-trimethoxyphenyl)prop-2-en-1-one
Dongsoo Koh
Acta Crystallographica Section E , 2013, DOI: 10.1107/s1600536813006843
Abstract: In the title molecule, C22H20O5, the C=C bond of the central enone group adopts an E conformation. The dihedral angle formed by the benzene ring and the naphthalene ring system is 12.6 (4)°. The hydroxy group attached to the naphthalene ring is involved in an intramolecular O—H...O hydrogen bond. In the crystal, weak C—H...O hydrogen bonds link the molecules into chains along [010]. In addition, π–π stacking interactions are present, with centroid–centroid distances of 3.6648 (15) and 3.8661 (15) between the benzene and two naphthalene rings.
8-Methoxy-2H-chromene-3-carbaldehyde
Dongsoo Koh
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812047319
Abstract: In the title molecule, C11H10O3, the fused dihydropyran ring is in a half-chair conformation with the O atom and the methylene C atom positioned 0.1318 (13) and 0.143 (2) , respectively, on either side of the mean plane formed by the other four atoms. In the crystal, weak C—H...O hydrogen bonds link molecules along [001].
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