Logarithmic Regression Equation Research Articles

Possible Reasons for Spurious Regression in the Econometric Model (Case Study of Imports in the United States of America)

Purpose: The research aims to identify statistical, econometric, and economic indicators to infer the problem of spurious regression. Theoretical framework: The research used a descriptive and econometric approach to identify the dimensions of this problem and the most likely causes of its emergence. Design/Methodology/Approach: The research estimated four equations, the first two are simple linear regressions (y, x1) and (y, x2), the third is a multiple linear regression equation (y, x1, x2), and the fourth is a double logarithmic regression equation for multiple linear regression. The results of the four equations were compared to assess the standard methods and explore spurious regression. Findings: The research concluded with several findings, one of which is that a high value of the coefficient of determination (R2) in the absence of significance of the parameters is an indication of the problem of multicollinearity, and hence the possibility of spurious regression. Research, Practical & Social implications: Spurious regression can lead to misleading conclusions about the relationships between economic variables, this can have negative consequences for economic policymaking and other decision-making processes. The research on spurious regression can help to improve the accuracy and reliability of economic analysis, which can benefit society as a whole. Originality/Value: The paper could provide recommendations for how to avoid spurious regression in econometric models of imports. This could include recommendations for data collection, data preparation, and model specification.

Significant impact of water-soluble organic matter on hygroscopicity of fine particles under low relative humidity condition

Uncertainties in estimating the hygroscopicity of bulk aerosols under conditions of low relative humidity (RH) or below the deliquescent RH (DRH) of aerosols remain to be significant, mainly due to the presence of water-soluble organic matter (WSOM). To quantify the contributions of WSOM to aerosol hygroscopicity and associated uncertainties, a field campaign was conducted to measure the hygroscopic growth curve (f(RH)) of bulk aerosols online, dominant chemical compositions in PM2.5 online and offline, and size distributions of the dominant chemical compositions offline during the dry and wet seasons of 2019–2020 in urban Guangzhou of south China. Based on the measured f(RH), the hygroscopicity parameter (κ) of bulk aerosols (κ-f(RH)) exhibits a logarithmic increase with increasing RH until RH reaches 69 %. Beyond this threshold, κ-f(RH) increases very slowly with further increase of RH, reaching 0.32 ± 0.04 during the dry season and 0.31 ± 0.05 during the wet season. The κ of WSOM (κ-WSOM) was further estimated to be 0.22 ± 0.03 and 0.13 ± 0.04 in the dry and wet seasons, respectively, when RH > 69 %. WSOM significantly affects κ-f(RH) by retarding the deliquescence process of aerosols and altering the mass ratio of water-soluble inorganic salts (WSIS) to WSOM within the size range of 0.4–0.9 μm, especially under low RH conditions (<60 %). The κ-f(RH) under low RH conditions was revised based on the logarithmic regression equation between RH and the ratio of measured κ-f(RH) to estimated κ-f(RH>69%). f(RH) of WSIS and WSOM were then corrected using the revised κ-f(RH) under low RH conditions, which showed 22–31 % lower values than those produced by the IMPROVE formulas.

A detailed study of the CHN-BQ rock mass classification method and its correlations with RMR and Q system and Hoek-Brown criterion

A CHN-BQ method is firstly defined to present the system and connotation of the current Chinese national standard “Standards for Engineering Classification of Rock Mass” GB/T 50,218. The core idea and content of the CHN-BQ method are studied in detail. Based on a qualitative classification of rock masses at the sites of in situ rock deformation and shear strength tests with a total number of 1439 test sets in nearly 90 projects, the statistical characteristics of in situ test results of different grades of rock mass are analyzed; Thus, the mechanical parameters corresponding to each grade of rock mass basic quality are proposed. Based on 997 groups of various rock mass classification data in 10 projects, the comprehensive CHN-BQ method verifies, and some essential remarks are obtained. Firstly, the 312 sets of parallelly measured data show that the consistency of less than one-grade discrepancy of the qualitative and quantitative classification in the CHN-BQ method is up to 71% in percentage. Secondly, a highly linear correlativity of the CHN-BQ method with the RMR method is found, and a linear regression equation is proposed. Thirdly, a logarithmic regression equation between the CHN-BQ method and the Q system is obtained, and equivalent grading divisions of the Q system from 9-level intervals towards traditional 5-level intervals are proposed. Finally, the research shows that the GSI concept in the Hoek-Brown criterion and the qualitative classification of rock mass structure in the CHN-BQ method are essentially coincident. Based on the measured data in quartz mica schist rock of an arch dam project, a linear regression equation of the Kv index in the CHN-BQ method and GSI index in the Hoek-Brown criterion is obtained, and the comparison of the strength parameters of the CHN-BQ method and Hoek-Brown criterion is discussed.

Mathematical Model for 100- and 200-meter Olympic Games Running Championship Time Records

The 100 and 200- meter running championships for both males and females were first held in 1948 at London Olympic Games 1948. Some time records made by the running champions have been continuously improved. Thus, running championship is not only intended to win the gold medals but also to make new world records. The secondary data were in the form of running championships' time records used to formulate the mathematical models and determine the minimum time limits (fastest). This research used the time-record data of 100 and 200- meter running championships for both males and females winning the gold medals from the Olympic Games held in 1948 to 2020. The mathematical Model for 100 and 200- meter running championships was more appropriately formulated using a logarithmic regression equation. Meanwhile, the time records for running championships of 100 meters for females as well as those of 200 meters for both males and females used a simple linear regression. The world record for running 100 meters for males still belongs to Usain Bolt (9.63 seconds). By using an assumption that the time records are normally distributed, those time records can be broken/improved into 9.53 seconds. Moreover, if the analysis is made using a box-plot diagram, the fastest time can be 9.42 seconds. A similar conclusion was also obtained for the world records of running 100 meters for females and 200 meters for males and females mentioning that the recently achieved time records still can be broken/improved in the future.

Calibration and comparison of various sensors for soil moisture measurement

The research paper introduces the development of a soil moisture sensor in accordance with the field condition and has a capacity to measure soil moisture up to 50 cm depth. In this study, the Arduino-based soil moisture sensors such as Stainless Steel 316L grade (SS316L) probe and Copper Based Probe (CBP) are introduced, which fit best with the conventional method for measuring soil moisture. The paper also presents the calibration and performance comparison of three sensors, including SS316L and CBP sensors (developed) and Manual Soil Moisture (MSM) sensors. The globally accepted and proven Oven Dry Method (ODM) is adopted for calibration purpose during soil moisture measurement. Linear, polynomial, and logarithmic regression equations, along with Adaptive Neuro-Fuzzy Inference System (ANFIS), are utilized for the best fitting. Thus, it proves that ANFIS non-linear system gives the best result. It is observed that the SS316L sensor performs well with the desired accuracy in the given field condition compared to other soil moisture sensors. The outcome of this study will assist the government authorities, policymakers, and researchers working on water-saving objectives.

A high‐throughput turbidimetric method for quantitative preparation of Plasmodiophora brassicae inoculum for bioassays

AbstractClubroot caused by Plasmodiophora brassicae is one of the major diseases on cruciferous crops. This disease has been a problem all over the world and led to serious economic losses in cruciferous crop production. The improvement of clubroot management is dependent on the effectiveness of bioassays on pathogenicity or plant resistance. P. brassicae resting spore inoculum prepared from clubroot tissues was widely used in bioassays. Traditionally, resting spore concentration was measured by visual counting with a haemocytometer; however, this method is time‐consuming, labour intensive and with poor repeatability due to the tiny size of resting spores. In this study, we established a turbidimetric method to measure P. brassicae resting spore concentration of the inoculum. A regression curve was generated by plotting optical density of gradiently diluted resting spore suspension against the corresponding resting spore concentrations, which resulted in a logarithmic regression equation. This method was validated and proved to be robust and effective in determining resting spore concentration of different samples, and was further confirmed by bioassay of infection and clubroot development. In conclusion, we established a standard protocol to prepare P. brassicae inoculum and provided an effective method for resting spore concentration determination. The results of this study can be widely used in research activities on clubroot sustainable management when an effective assessment of P. brassicae biomass is needed.

Нарушение осмотического баланса в условиях нетравматического субарахноидального кровоизлияния

Актуальность. Аневризматическое субарахноидальное кровоизлияние является распространенным и серьезным заболеванием, которое может приводить к летальным последствиям. Цель исследования: изучить динамику натриемии в контексте ее клинико-патогенетического значения у пациентов с субарахноидальным кровоизлиянием. Материалы и методы. Обследовано 87 пациентов с субарахноидальным кровоизлиянием, из них 38 (43,68 %) — с изолированным субарахноидальным кровоизлиянием, 14 (16,09 %) — с субарахноидально-паренхиматозным, 29 (33,33 %) — с субарахноидально-желудочковым, 6 (6,9 %) — с субарахноидально-паренхиматозно-желудочковым кровоизлиянием, общее количество смешанных кровоизлияний составляло 56,32 %. Для проведения полного ангиографического исследования использовали ангиографический комплекс AXIOM Artis MP «Siemens». Результаты. Исследование SIADH-синдрома (синдром неадекватной секреции антидиуретического гормона) с развитием гипонатриемии у пациентов с субарахноидальным кровоизлиянием нетравматического генеза свидетельствует о тесной ассоциации между выраженностью нарушений осмотического гомеостаза и тяжестью клинического течения субарахноидального кровоизлияния согласно модифицированной шкале Fisher, шкале WFNS, шкале Нunt &amp; Неss, шкале результатов GOSE (Glasgow Outcome Scale Extended) и обобщающей классификационной шкале для оценки прогноза исхода субарахноидального кровоизлияния (Ogilvy C.S. et Carter B.S.). У лиц с гипонатриемией на фоне субарахноидального кровоизлияния сопряженность сывороточного уровня натрия и показателя сывороточного уровня копептина адекватно и достоверно аппроксимируется уравнением регрессии логарифмического характера (по основанию 10), при значениях копептина более 0,70 нг/мл в более чем 50 % случаев регистрировалась натриемия средней тяжести. Выводы. Была обнаружена достоверная тесная взаимосвязь между уровнем данного пептида с нейроэндокринными свойствами — копептина и нарушением осмотического гомеостаза ионов натрия на фоне субарахноидального кровоизлияния с различной тяжестью клинического течения.

Perbandingan Model Regresi untuk Pengukuran Luas Daun Gandum di Daerah Tropis

The growth of wheat plants can be determined by measuring leaf area index and net assimilation rate. Both measurements require leaf area data. Measurement of leaf area of wheat in Indonesia requires a method that is not only accurate, but also easier and cheaper. One of them is the regression method. The purpose of this study was to determine an accurate regression equation model in predicting wheat leaf area. This research was conducted from March to June 2021 at the Experimental Station and Plant Production Technology Laboratory, Faculty of Agriculture, UNPAD, Jatinangor, Sumedang. The materials used in this study were various leaf area printing papers from wheat plants aged 14 days after planting (DAP), 28 DAP, and 42 DAP. The regression equation was assembled from the relationship between leaf area with leaf width and length, then compared with the actual leaf area that measured by scanning. The results showed that the linear, quadratic, cubic, and logarithmic regression equations had a coefficient of determination of more than 90% to predict leaf area, at the age of 14, 28, and 42 DAP, as well as all plant ages. Quadratic regression had a limit of data that can be entered, so it needed circumspection in using the formula. Cubic regression tended to have better accuracy in predicting leaf area at 14, 28, and 42 DAP, but the accuracy was the same as other regression equations at all plant ages.

Energy and Protein Requirements for the Maintenance of Growing Male Sika Deer (Cervus nippon).

The objective of this study is to study the effects of dietary intake levels on energy metabolism, carbon (C), and nitrogen (N) balance and to determine the maintenance requirements of energy and protein for male sika deer during their growing period. A total of 16 1-year-old male sika deer with similar body weight (BW) (63.25 ± 2.42 kg) were selected, with four animals per feed intake level. The feeding levels of the four groups for deer were 40, 60, 80, and 100% of the recommended amount, respectively. The nutrient digestibility and methane production were measured through digestion trials and respiratory trials. A 4 × 4 Latin Square design was performed in a respirometry trial. The results show that the apparent digestibility of C and N gradually increased as the level of feed intake decreased. Furthermore, with a decrease in feed intake level, the metabolic energy intake (MEI), heat production (HP), and retained energy (RE) of male sika deer significantly decreased (P < 0.01). The requirements of metabolic energy for maintenance (MEm) and net energy for maintenance (NEm) of growing deer are 251.17 and 223.62 kJ kg−1BW0.75d−1, respectively, as estimated according to the logarithmic regression equations between HP and MEI. The net N requirement for maintenance (NNm) and net protein requirement for maintenance (NPm) of growing male sika deer based on the linear relationship between retained nitrogen (RN) and daily nitrogen intake (NI) were 251.8 mg kg−1BW0.75d−1 and 1.57 g kg−1BW0.75d−1, respectively. The NEm and NPm values obtained from this experiment fill the gap in net energy and protein requirements and serve as basic data for establishing the nutritional standards forsika deer breeding in China.

On the Enterprise Dynamic Management in the COVID-19 Pandemic

On the Enterprise Dynamic Management in the COVID-19 Pandemic

MORFOMETRICS OF MALE PASUNDAN CALVES ON DIFFERENT AGES UNDER EXTENSIVE REARING

ABSTRACTThis research on Morphometrics of Male Pasundan on Various Age was carried out in July 2018 in Cibalong District, South Garut Regency, West Java. This study aims to determine the relationship between body size of male calves at various ages and estimation of body weight using body size. The object in this study was 28 male calves at the age of 1-12 months. The results showed a relationship (R2 approaching 1) with the equation of each measurement, namely the Logarithmic regression equation for body lenght and chest deep (96,837ln(x) – 311,88), Polinomial regression equation for body and length body height (-0144x2 + 2,9524x – 48,433), Power regression equation for chest deep and chest girth (0,5317x0,9285), Logarithmic regression equation for body length and chest deep (34,974ln(x) – 110,5), Polynomial regression equation for body height and chest deep (0,004x2 - 0,1438x + 19,89). The result also show that the best model of estimating the body weight of Pasundan cattel is to use the the Polynomial formula with the equation y= 0.218x2 – 2.2536x + 76.074 where x is the size of the calf’s chest girth.Keyword: Extensive, morphometrics, pasundan male calf, weight estimation, polynomial

Evaluation of Statistical Methods for Estimating Missing Daily Streamflow Data

In this study, it was aimed to investigate applicability of various statistical estimation methods for Porsuk River basin, which has sparse streamflow observations. Estimations were performed using regression, single and multiple donor stations based drainage area ratio, standardization with mean (SM), standardization with mean and standard deviation (SMS), inverse distance weighted methods. Two seperate studies were conducted for both partially missing data and completely missing data. In order to estimate streamflow statistics for use in SM and SMS methods, logarithmic regression equations were suggested. The promising results obtained from ensemble approaches will provide a significant hydrological contribution to streamflow estimations.

Allometric biomass equations for young trees of four broadleaved species in Albania

Background: Biomass assessment of young forest stands is important because of their role in the carbon cycling. The aim of this study was to develop biomass equations for young broadleaved species growing in natural conditions in Albania. Methods: Five forest stands were investigated using circular sample plots. Diameter at breast height (DBH) and height (H) from 58 sampled trees ranging in age from 4 to 34 years old of Turkey oak (Quercus cerris L.), sweet chestnut (Castanea sativa Mill.), European hornbeam (Carpinus betulus L.) and manna ash (Fraxinus ornus L.) were measured in situ. Logarithmic regression equations were used and tested for their performance to estimate aboveground and tree-components biomass for each species using DBH, H and their combination DBH2 x H as predictors. Results: We found that DBH was a reliable predictor for estimation of aboveground and components biomass for young trees but the inclusion of height in biomass allometry did not improve the biomass estimation. We observed differences in scale (?0) and exponent (?1) coefficients of biomass models, not only between broadleaved species, but also among tree-components within species. Both coefficients were strongly species-specific and their values reflect differences in biomass stocking rate due to different growth strategies of each species in early development phases. Conclusions: Allometric equations to estimate aboveground and tree-component biomass appeared to be species-specific, meaning that such models are applicable for species growing at sites with similar ecological conditions. From the tree variables used, DBH was the most reliable predictor of aboveground and individual components biomass, whereas height proved to be a promising predictor for stand biomass. These allometric equations developed for young trees will improve the accuracy of current estimates of forest carbon stock in Albania.

Correlations of left ventricular systolic function indices with aortic root systolic excursion (ARSE): A cross-sectional echocardiographic study.

BackgroundHeart failure (HF), is a major public health issue globally. Echocardiography is cost–effective in the diagnosis in expert hands. This study was conducted to estimate the usefulness of Aortic Root Systolic Excursion (ARSE) as a simple and accurate measure to estimate Left Ventricular (LV) function.MethodsThis was a cross-sectional echocardiographic study among adults aged ≥ 18 years, with or without heart failure, in sinus rhythm, and with no LV out–let obstruction. We studied the correlations of ARSE with some selected indices of LV Systolic Functions. We determined optimal cut–offs of ARSE in detecting LV dysfunction. We generated a simple regression equation to best estimate LV ejection fraction according to the modified Simpson method.ResultsOverall 213 echocardiograms were included from 106 males (49.8%), with mean age of the participants being 52.4 (SD: 18.3) years. The rate of LV systolic dysfunction was highest with Teicholz method (17.4%) and lowest with MAPSE method (5.2%). ARSE correlated with the LV functions. This was highest for the Simpson method (r = 0.619, p<0.001), and lowest for the ITV method (r = 0.319, p<0.001). Optimal cut-offs to detect LV systolic dysfunction was ≈ 6.6 mm. For an LV ejection fraction < 55%, the sensitivity was 82.9%, and the specificity was 97.2%, with an AUROC of 91.6%.The logarithmic regression equation was best in predicting LV ejection fraction (AUC: 60.2%), followed by the power model (AUC: 56.7%), and the linear model (AUC: 53.6%).ConclusionARSE correlated well with LV systolic function. The cut–off ≤ 6.5 mm suggest LV systolic dysfunction. LV Ejection Fraction was best estimated with the generic equation: LVEF (%) = 29 x In [ARSE].

Synthesis, crystal structure and DNA/protein binding of tetranuclear Cu(II) complexes with a double-open-cubane like core framework

The copper(II) complexes [Cu4(L)2(HL)2(H2O)2]∙2(ClO4)∙2(H2O)∙DMF (1) and [Cu4(L)2(HL)2(H2O)2]∙(tp) (2) [H2L = 2-ethoxy-6-[(1-hydroxymethyl-propylimino)-methyl]-phenol; tp = terephthalate] have been synthesized and characterized by single crystal X-ray diffraction and spectroscopic studies. The structural determination reveals that both the complexes are tetranuclear with a double-open-cubane like core framework. The 2D supramolecular structure of 1 and 3D supramolecular structure of 2 are formed through C–H…π and hydrogen bonding interactions, respectively. At room temperature both the complexes exhibit fluorescence with quantum yields of 0.41 and 0.40. The interactions of the complexes with calf thymus DNA (CT-DNA) and serum albumins were investigated using electronic absorption and fluorescence spectroscopic techniques. The studies revels that the binding affinities of 1 and 2 with CT-DNA are of the order 8.86 × 105 M−1 and 7.14 × 105 M−1, respectively. Additionally, the interaction of the complexes with bovine serum albumin and human serum albumin were studied and the number of binding sites and binding constants were calculated using a double logarithm regression equation. The redox activities of the complexes were investigated in methanol solution by cyclic voltammetry.

The effects of cryoprotectants on sperm motility of the Chinese pearl oyster, Pinctada fucata martensii

Cryopreservation has been widely employed to preserve genetic material of aquatic animals. Although of common use in bivalves, resulting effects due to the toxicity of the cryoprotectants dimethyl sulfoxide (DMSO), propanediol (PG), methanol (MET) and ethylene glycol (EG), upon sperm motility in the Chinese pearl oyster, Pinctada fucata martensii, has remained undocumented. This study endeavors to identify the least toxic among the effective cryoprotectant agents by observing and comparing their toxic effects on sperm motility under varying concentrations and duration of exposure. Sperm samples were exposed during controlled experiments, for 1, 3, 6, 9, 12 and 15 min durations, to each of the listed cryoprotectants at 5, 10, 15, and 20% (volume:volume) concentrations. Sperm motility was observed to diminish when exposed to all cryoprotectant solutions, and observations demonstrated that toxicity increased relative to both concentration and equilibration time. After 6 min of exposure to the cryoprotectants, sperm motility was seen to have diminished significantly in DMSO at just 5% concentration, and in MET, PG and EG at 10% concentrations, respectively (the values of the lowest observed effect concentrations). The relationship between the quantity of immotile sperm and the cryoprotectant concentration was described using the logarithmic regression equation. MET exhibited the lowest effective concentration required to inhibit sperm motility by 50% (EC50), followed by EG, PG and DMSO, in order. Therefore, MET proved most toxic under the test conditions for sperm of P. fucata martensii, whereas DMSO, PG and EG were observed as comparatively safer, suggesting that DMSO, PG and EG warrant further study in the application of cryopreservation of Chinese P. fucata martensii sperm.

A New Mixture Refrigerant for Space Heating Air Source Heat Pump: Theoretical Modelling and Performance Analysis

Air source heat pump (ASHP) is becoming a substitute for small coal boilers in rural residential buildings of North China. However, the application of ASHP faces challenges of heating capacity, energy efficiency, ozone depletion potential (ODP) and global warming potential (GWP). Proper refrigerant is a key factor influences the performance of ASHP. In this paper, a new mixture refrigerant named RHR-1 is proposed, which aimed to improve energy efficiency, eliminate ODP and reduce GWP of ASHP refrigerant. The performance of RHR-1 was analyzed and compared with commonly used refrigerants including R134a, R410A, R407C and R22 in terms of heating coefficient of performance (COPh), compression ratio (CR) and discharging temperature (DT). The results show that, under the design cases, where supply water temperatures vary from 35 °C to 50 °C and outdoor air temperatures vary from −15 °C to 15 °C, the COPh of RHR-1 are in the range of 2.43–4.93. The COPh of RHR-1 is higher than other candidates when the supply water temperature is above 40 °C. The CR and DT of RHR-1 are in medium levels of the compared samples. A logarithmic regression equation was deduced to get the relationship of COPh with temperature difference between supply water and outdoor air which suggested the temperature difference should be controlled within 47.5 °C to get reasonable COPh. In addition, RHR-1 has no ODP, and its GWP is 279, which is much lower than other candidates. RHR-1 could be a reasonable refrigerant used in ASHP for space heating in North China.

DNA/protein binding and magnetic properties of a 1D Cu(II) complex containing fumarate and tridentate Schiff base ligands

The 1D copper(II) complex {[Cu2(L)2(fum)]·(H2O)·(MeOH)}n (1) has been synthesized using fumarate (fum2−) and a Schiff base (HL), derived from the condensation reaction of 2-amino-1-butanol and salicylaldehyde. Complex 1 has been characterized by its X-ray crystal structure, together with FT-IR, electronic absorption and fluorescence spectroscopic methods. The structural determination reveals that complex 1 crystallizes in the monoclinic system with the space group P21/n and forms a 1D polymeric chain, built by bridging fum ligands. Weak π⋯π and C–H⋯π interactions lead to the formation of a 3D supramolecular architecture. Complex 1 exhibits fluorescence (λex, 366nm; λem, 410, 433 and 462nm) at room temperature, with a quantum yield (Φs) of 0.257. The interactions of complex 1 with bovine serum albumin (BSA) and human serum albumin (HSA) were studied using electronic absorption and fluorescence spectroscopic techniques, and the results show that the interaction of complex 1 with BSA/HSA occurs mainly with a ground state association process. The calculated values of the apparent association constants (at 300K) are 1.34×104 and 1.81×104Lmol−1 for interactions with BSA and HSA, respectively. The number of binding sites and binding constants were calculated using a double logarithm regression equation. The interaction of complex 1 with calf thymus DNA (CT-DNA) was also investigated using electronic absorption and fluorescence spectroscopic methods. The results show that complex 1 has a binding affinity to CT-DNA of the order of 2.96×105Lmol−1. Low temperature magnetic measurements reveal the existence of an antiferromagnetic interaction in complex 1. The magnetic data have been fitted considering complex 1 as a pseudo-dinuclear system, with the two copper(II) ions bridged by two carboxylate oxygen atoms, since the coupling through long fum bridge is almost nil. The best-fit parameters obtained with this model are J=−60cm−1 and gCu=2.20.

미계측 유역의 유황곡선 산정을 위한 지역회귀모형의 개발

본 연구에서는 지형 및 기상학적 인자만으로 미계측 유역의 저유량부 유황곡선을 추정할 수 있는 지역회귀모형을 개발하고자 하였다. 이를 위해서 16개 유역의 계측 자료로부터 저유량 영역(지속일수 185일에서 365일)에 대한 유황곡선을 작성하고, 이를 토대로 로그형태의 이변수 회귀모형을 구축하였다. 이 회귀모형을 미계측 유역에 적용할 수 있도록 유역면적, 유역경사, 수계밀도, 연평균강수량, 연평균유출량, 유출곡선지수 등의 유역특성인자를 이용하여 모형의 매개변수를 지역화 하였다. 개발한 지역회귀모형으로 평균갈수량, 평균저수량, 평균평수량을 추정하여 관측값과 비교한 결과, 유역면적, 유출곡선지수, 연평균강수량 조합으로 구성된 지역회귀모형이 가장 우수한 것으로 분석되었다. The objective of this study is to develop the regional regression models based on the physiographical and climatological characteristics for estimating flow duration curve (FDC) in ungauged bsisns. To this end, the lower sections with duration from 185 to 355 days of FDCs were constructed from the 16 gauged streamflow data, which were fitted to the two-parameter logarithmic type regression equation. Then, the parameters of the equation were regionalized using the basin characteristics such as basin area, basin slope, drainage density, mean annual precipitation, mean annual streamflow, runoff curve number in order that the proposed regression model can be used for ungauged basin. From the comparison of the estimated by the regional regression model with the observed ones, the model with the combination of basin area, runoff curve number, mean annual precipitation showed the best performance.

DNA/protein binding, cytotoxicity and catecholase activity studies of a piperazinyl moiety ligand based nickel(II) complex

The Ni(II) complex, {[Ni(HL)(SCN)2(H2O)]·2(DMF)} (1) [HL=6-methoxy-2-{[2-(1-piperazinyl)ethylimino]methyl}phenol], was synthesized and characterized by X-ray crystal structure analysis and spectroscopic methods. The crystal structure of complex 1 reveals a distorted octahedral coordination geometry around the nickel centre which forms a supramolecular assembly through hydrogen bonds. The interaction of complex 1 with the calf thymus DNA (CT-DNA) was investigated using electronic absorption and fluorescence spectroscopic methods. The results show that complex 1 has binding affinity to CT-DNA in the order of 6.06×105M−1. The interactions of complex 1 with bovine serum albumin (BSA) and human serum albumin (HSA) were also studied using electronic absorption and fluorescence spectroscopic techniques and the analysis show that interaction of complex 1 with BSA/HSA occur mainly with ground state association process. The number of binding sites and binding constant were calculated using double logarithm regression equation. Anticancer activity of 1 in human breast (MCF7) cancer cell lines reveals dose dependent suppression of cell viability with IC50 value 64±3.7μM. Catecholase activity of 1 has been investigated in methanol medium using 3,5-di-tert-butylcatechol (3,5-DTBC) as model substrate and the result shows that 1 is active for catalyzing aerobic oxidation of 3,5-DTBC to 3,5-di-tert-butylbenzoquinone (3,5-DTBQ).