Strong Negative Linear Relationship Research Articles

A Quantitative Quality Measurement for Codebook in Feature Encoding Strategies

Nowadays, a feature encoding strategy is a general approach to represent a document, an image or audio as a feature vector. In image recognition problems, this approach treats an image as a set of partial feature descriptors. The set is then converted to a feature vector based on basis vectors called codebook. This paper focuses on a prior probability, which is one of codebook parameters and analyzes dependency for the feature encoding. In this paper, we conducted the following two experiments, analysis of prior probabilities in state-of-the-art encodings and control of prior probabilities. The first experiment investigates the distribution of prior probabilities and compares recognition performances of recent techniques. The results suggest that recognition performance probably depends on the distribution of prior probabilities. The second experiment tries further statistical analysis by controlling the distribution of prior probabilities. The results show a strong negative linear relationship between a standard deviation of prior probabilities and recognition accuracy. From these experiments, the quality of codebook used for feature encoding can be quantitatively measured, and recognition performances can be improved by optimizing codebook. Besides, the codebook is created at an offline step. Therefore, optimizing codebook does not require any additional computational cost for practical applications.

Site energy distribution analysis and influence of Fe3O4 nanoparticles on sulfamethoxazole sorption in aqueous solution by magnetic pine sawdust biochar

Magnetisation of carbonaceous adsorbents using iron oxides has been found to be one of the potential solutions for easy recovery of adsorbent after use. We evaluated the effects of Fe3O4 nanoparticle addition on the physico-chemical properties of biochar and its sorption properties. Five adsorbents with varying amount of Fe3O4 per mass of adsorbent (0%, 25%, 50%, 75% and 100%) were used to adsorb sulfamethoxazole (SMX), an emerging micropollutant. Five isotherm models were used to evaluate the sorption behaviour of SMX onto the adsorbents where Redlich-Peterson model was found to best describe the data. Based on this model, the approximate site energy distribution for each adsorbent was determined. Surface area and sorption capacity had strong negative linear relationship with the amount of Fe3O4 per mass of adsorbent while the pore volume and saturation magnetisation of the adsorbent increased with increasing percentage of Fe3O4. The results of the approximate site energy distribution analysis showed that the addition of Fe3O4 on biochar reduced the area under the frequency distribution curve of sorption site energies leading to the lowering of the sorption sites available for SMX. This could be attributed to the blockage of the hydrophobic surface of biochar reducing the hydrophobic interaction between SMX and biochar.

Cortical beta EEG oscillations related to changes in muscle tone activity during sleep in spider monkey (Ateles geoffroyi).

The physiological mechanisms that allow for sleeping in a vertical position, which is primordial for arboreal primates, have not been studied yet. A non-invasive polysomnographic study of 6 spider monkeys (Ateles geoffroyi) was conducted. The relative beta power of the motor cortex and its linear relation with muscle tone in the facial mentalis muscle and the abductor caudae medialis muscle of the tail during wakefulness and sleep stages were calculated. A strong negative linear relationship (r=-.8, P=.03) was found between the relative power of the beta2 band in the left motor cortex and abductor caudae medialis muscle tone during delta sleep. The left motor cortex, through beta2 band activity, interacts with abductor caudae medialis muscle tonicity during delta sleep. This interaction takes part in the mechanisms that regulate the sleep postures.

Affordability of comprehensive community health worker programmes in rural sub-Saharan Africa

IntroductionCommunity health worker (CHW) programmes have low costs per person served and are central to achieving universal healthcare. However, their total cost is high and the target of one million...

Can remote infrared cameras be used to differentiate small, sympatric mammal species? A case study of the black-tailed dusky antechinus, Antechinus arktos and co-occurring small mammals in southeast Queensland, Australia.

The black-tailed dusky antechinus (Antechinus arktos) is an endangered, small carnivorous marsupial endemic to Australia, which occurs at low population density along with abundant sympatric populations of other small mammals: Antechinus stuartii, Rattus fuscipes and Melomys cervinipes. Using A. arktos as a model species, we aimed to evaluate the effectiveness of infrared digital camera traps for detecting and differentiating small mammals and to comment on the broad applicability of this methodology. We also sought to understand how the detection probabilities of our target species varied over time and characterize their activity patterns. We installed 11 infrared cameras at one of only three known sites where A. arktos occurs for five consecutive deployments. Cameras were fixed to wooden stakes and oriented vertically, 35 cm above ground, directly facing bait containers. Using this method, we successfully recorded and identified individuals from all four species of small mammal known previously in the area from live trapping, including A. arktos. This validates the effectiveness of the infrared camera type and orientation for small mammal studies. Periods of activity for all species were highly coincident, showing a strong peak in activity during the same two-hour period immediately following sunset. A. arktos, A. stuartii and M. cervinipes also displayed a strong negative linear relationship between detection probability and days since deployment. This is an important finding for camera trapping generally, indicating that routine camera deployment lengths (of one-to-two weeks) between baiting events may be too long when targeting some small mammals.

Evaluation of Urbanization Dynamics and its Impacts on Surface Heat Islands: A Case Study of Beijing, China

As the capital of China, Beijing has experienced a continued and rapid urbanization process in the past few decades. One of the key environmental impacts of rapid urbanization is the effect of urban heat island (UHI). The objective of this study was to estimate the urbanization indexes of Beijing from 1992 to 2013 based on the stable nighttime light (NTL) data derived from the Defense Meteorological Satellite Program’s Operational Line Scanner System (DMSP/OLS), which has became a widely used remote sensing database after decades of development. The annual average value nighttime light Digital Number (NTL-DN), and the total lit number and urban area proportion within Beijing’s boundary were calculated and compared with social-economic statistics parameters to estimate the correlation between them. Four Landsat thematic mapper (TM) images acquired in 1995 and 2009 were applied to estimate the normalized difference vegetation index (NDVI) and normalized land surface temperature (LSTnor), and spatial correlation analysis was then carried out to investigate the relationship between the urbanization level and NDVI and LSTnor. Our results showed a strong negative linear relationship between the NTL-DN value and NDVI; however, in contrast, a strong positive linear relationship between existed between the NTL-DN value and LSTnor. By conducting a spatial comparison analysis of 1995 and 2009, the vegetation coverage change and surface temperature difference were calculated and compared with the NTL-DN difference. Our result revealed that the regions of fast urbanization resulted in a decrease of NDVI and increase of LSTnor. In addition, choropleth maps showing the spatial pattern of urban heat island zones were produced based on different temperatures, and the analysis result indicated that the spatial distribution of surface temperature was closely related with the NTL-DN and NDVI. These findings are helpful for understanding the urbanization process as well as urban ecology, which both have significant implications for urban planning and minimize the potential environmental impacts of urbanization in Beijing.

Impact of high moisture conditions on the serviceability performance of wood plastic composite decks

Wood plastic composites (WPCs) are being increasingly used as alternatives to wooden decks. In the present study, it was verified the potential loss of stiffness of WPC deck boards as a result of moisture intake. It was also assessed the importance of moisture intake in the fulfilment of serviceability limit states. For these purposes, three different types of commercial WPC decks were studied, with high (WPCH), medium (WPCM) and low (WPCL) expected mechanical performance. Different experimental designs were followed to simulate full exposure to outdoor conditions and the effect of possible internal stress due to differential shrinkage and the swelling behaviour of fibres and the matrix. The results indicate a high loss of bending modulus of elasticity due to water absorption (between 40 and 50%) and shrinkage/swelling movements (between 22 and 29%). This level of stiffness loss has a direct impact on ensuring the compliance to the serviceability limit states. A strong negative linear relationship between water absorption and the loss of bending stiffness was established, which can be a helpful tool to assist manufacturers in defining the application rules and ensuring the expected service life of their products.

Assessment of the association between Apgar scores and seizures in infants less than 1 year old

PurposeThe study aimed to assess the association between Apgar scores at 1 and 5min after birth and seizures in infants less than 1 year old. MethodsWe conducted a retrospective, observational, hospital-based study by utilising medical records from the Chung-Ang University Hospital admissions from January 2006 to May 2015 in order to identify infants less than 1 year old who had a history of seizures. Using electronic medical records, infants who were diagnosed with infantile seizures at the Chung-Ang University Hospital from January 2006 to May 2015 were included in the seizure group (n=93), and a control group consisting of 296 age-matched cases without a history of seizures was selected from a group of infants born at Chung-Ang University Hospital during the same study period. ResultsWe found that Apgar scores were significant risk factors for infantile seizures. Apgar scores differed depending on gestational age and birth weight. We found strong associations between Apgar scores and infantile seizures in the full-term and the normal-birth weight groups (bodyweight ≥2.5kg), regardless of delivery mode. The Apgar scores were inversely correlated with the EEG class, and only the 1-min Apgar scores were correlated with MRI findings. ConclusionLow Apgar scores are significant perinatal risk factors for infantile seizures, especially in full-term and normal-birth weight infants, and have a strong negative linear relationship with EEG and brain MRI results in the seizure group.

The Relationship Between Forensic Accountants’ Skepticism and Audit Expectation Gap Among Nigerian Money Deposit Banks

This paper examines how forensic Accountant's skepticism can narrow audit expectation gap among Nigeria Money Deposit Banks. The specific objectives of the study were to determine the relationship between forensic Accountants' investigation tenure and lack of time budget pressure by forensic Accountant among Nigeria Money Deposit Bank. Two hypotheses were formulated and tested. A survey design was used to gather the information needed to achieve the objectives. A census was carried out in twenty one Nigeria Money Deposit Banks which had operating licenses from the Central bank of Nigeria. Open ended and closed ended questionnaires were used to collect the data. The findings of the study revealed that there was a strong negative linear relationship between the independent variables and dependent variable. Based on the findings, it was recommended that there is need to establish and structure necessary legal framework for forensic accounting and investigation and legislate forensic audit as in the case of financial audit legislated.

NO3-N and Metolachlor Concentrations in the Soil Water as Affected by Water Table Depth

Experiments were conducted in lysimeters to study the effect of shallow water table (WT) depths on the transport of two commonly used agricultural chemicals, nitrate-N and metolachlor, to shallow groundwater. Groundwater samples were collected from 0.20-, 0.40-, and 0.60-m depths using suction tubes during the growing season. The results showed significant reductions in both nitrate-N and metolachlor concentrations in the groundwater by maintaining shallow WT depths. Lowest concentrations of nitrate-N and metolachlor in the groundwater were observed when WT were maintained at 0.15-m depth. Generally, nitrate-N concentrations were increased with the soil depth while metolachlor concentrations decreased with the sampling depth during the growing season. Analysis of drainage outflow data at the end of WT treatment period also provided the evidence of the effectiveness of shallow WTs in reducing chemicals losses to shallow groundwater systems. The results of this study indicated that nitrate-N and metolachlor concentrations in the drainage outflow were 54 and 45%, respectively, lower for the 0.15-m WT treatment than the 0.60-m WT treatment. Regression analysis showed a strong negative linear relationship between metolachlor concentration and days after planting (DAP). Soybean yield was significantly reduced with the rise in WT depth. Average soybean yield obtained for the 0.15-m WT depth was 42% lower than the 0.60-m WT depth. It can be concluded from the overall results of this study that shallow WTs can be used effectively to reduce the nitrate-N and metolachlor losses to the shallow groundwater.

Topographic controls on soil nitrogen availability in a lowland tropical forest

Geomorphic position often correlates with nutrient cycling across landscapes. In tropical forests, topography is known to influence phosphorus (P) availability, but its effect on nitrogen (N) cycling has received less exploration, especially in lowland forests where widespread N richness is frequently assumed. Here, we report significant effects of topographic slope and landscape position on multiple aspects of the N cycle across a highly dissected lowland tropical forest on the Osa Peninsula, Costa Rica. A suite of N cycle metrics measured along a topographic sequence revealed a distinct gradient in N availability. Values of soil δ15N, inorganic N pools, net nitrification rates, and nitrification potentials were all substantially lower on a flanking steep hillslope (~28°) compared to a relatively flat ridge top (~6°), indicating lower N availability and a less open N cycle in steep parts of the landscape. Slope soils also hosted smaller total carbon and nitrogen stocks and notably less weathered soil minerals than did ridge soils. These latter findings suggest that elevated N loss resulting from high rates of soil and particulate organic matter erosion could underpin the spatial variation in N cycling and availability. Expanding our analysis to the larger study landscape, a strong negative linear relationship between soil δ15N values and surface slope angles was observed. N isotope mass balance models suggest that this pattern is most plausibly explained by an increase in N loss via erosive, non‐fractioning pathways from steep zones, as most other variables commonly assumed to affect soil δ15N values (such as temperature, precipitation, and vegetation type) did not vary across the sampled region. Together, these results reveal notable hillslope‐scale variation in N richness and suggest an important role for non‐fractionating N loss in the maintenance of this pattern. Such findings highlight the importance of geomorphology and the significant capacity of erosion to influence N availability in steepland ecosystems.

서해안 태안 어은리 갯벌의 연속관측 메탄(CH<sub>4</sub>) 플럭스 특성 평가

2014년 8월 31일~9월 1일 충남 태안 어은리 갯벌 퇴적물의 동일한 실험 장소에서 닫힌 챔버를 이용하여 챔버내 가스들(메탄(<TEX>$CH_4$</TEX>), 이산화탄소(<TEX>$CO_2$</TEX>) 및 산소(<TEX>$O_2$</TEX>))의 갯벌 표면 노출시 일조량이 있는 조석주기의 저조 시점을 기준으로 각 기체의 플럭스량을 파악하기 위해 총 6회 실험하였다. 챔버 내에서 채취된 대기 샘플 중 메탄의 농도는 6시간 이내에 지구온실가스 측정용 EG model GS-23 가스크로마토그래피로 분석하였으며 그 외 가스종은 Multi Gas Monitor를 이용하여 실시간 측정하였다. 각 가스 종들의 배출원(source (+)) 또는 흡수원(sink (-))의 플럭스 계산값은 단순 선형 회귀분석을 이용하여 시간에 따른 각 기체의 농도변화인 1차 함수 기울기 값을 수식에 대입하여 계산하였다. 또한 주변 환경 특성을 참고하기 위해 퇴적물 함수율, 온도, 총유기탄소, 챔버내 온도 및 퇴적물 퇴적상도 측정하였다. 첫째날, 총 3회 플럭스 측정이 진행되는 5시간 20분 동안 이산화탄소는 <TEX>$-137.00{\sim}-81.73mg/m^2/hr$</TEX> 흡수원, 산소는 <TEX>$-0.03{\sim}0.00mg/m^2/hr$</TEX> 흡수원 그리고 둘째날, 이산화탄소는 -20.43~-2.11 mg/m2/hr 흡수원, 산소는 <TEX>$-0.18{\sim}-0.14mg/m^2/hr$</TEX> 흡수원으로 모두 동일하였다. 메탄의 경우 양일간 조석주기의 저조 시점이 되기 전에는 첫째날 <TEX>$-0.02mg/m^2/hr$</TEX> 흡수원(SPSS 통계분석을 이용한 Pearson 상관계수는 뚜렷한 음의 선형관계인-0.555(n=5, p=0.332)) 및 둘째날 <TEX>$-0.15mg/m^2/hr$</TEX> 흡수원(상관계수는 강한 음의 선형관계인 -0.915(n=5, p=0.030))으로 작용하였다. 그리고 저조시점 이후로 메탄은 첫째날 최소 <TEX>$+0.00mg/m^2/hr$</TEX> 배출원(상관계수는 거의 무시될 수 있는 선형관계인 +0.713(n=5, p=0.176)) 및 둘째날 최대 <TEX>$+0.03mg/m^2/hr$</TEX> 배출원(상관계수는 약한 양의 선형관계인 +0.194(n=5, p=0.754))이 된다는 플럭스 양상은 양일간 모두 같았다. 그러나 <TEX>$CH_4$</TEX> 플럭스 값은 일자 및 시간별로 모두 다르게 분석되었다. 이러한 결과는 같은 시간, 동일지역 퇴적물 일지라도 <TEX>$CH_4$</TEX> 플럭스 변화율은 갯벌 근처 해수의 표층 조석주기 특성 이해를 통한 가스 방출 상관관계 및 물리화학적 퇴적물 환경과 같은 주변 변수에 따라 영향을 받음 수 있음을 보여준다. In 2014, on 31 August and 1 September, the emissions of <TEX>$CH_4$</TEX>, <TEX>$CO_2$</TEX>, and <TEX>$O_2$</TEX> gases were measured six times using the closed chamber method from exposed tidal flat sediments in the same position relative to the low point of the tidal cycle in the Eoeun-ri, Taean-gun, on the Mid-western Coast of Korea. The concentrations of <TEX>$CH_4$</TEX> in the air sample collected in the chamber were measured using gas chromatography with an EG analyzer, model GS-23, within 6 hours of collection, and the other gases were measured in real time using a multi-gas monitor. The gas emission fluxes (source (+), and sink (-)) were calculated from a simple linear regression analysis of the changes in the concentrations over time. In order to see the surrounding parameters (water content, temperature, total organic carbon, average mean size of sediments, and the temperature of the inner chamber) were measured at the study site. On the first day, across three measurements during 5 hours 20 minutes, the observed <TEX>$CO_2$</TEX> flux absorption was -137.00 to <TEX>$-81.73mg/m^2/hr$</TEX>, and the <TEX>$O_2$</TEX> absorption, measured simultaneously, was -0.03 to <TEX>$0.00mg/m^2/hr$</TEX>. On the second day using an identical number of measurements, the <TEX>$CO_2$</TEX> absorption was -20.43 to <TEX>$-2.11mg/m^2/hr$</TEX>, and the <TEX>$O_2$</TEX> absorption -0.18 to <TEX>$-0.14mg/m^2/hr$</TEX>. The <TEX>$CH_4$</TEX> absorption before low tide was <TEX>$-0.02mg/m^2/hr$</TEX> (first day, Pearson correlation coefficient using the SPSS statistical analysis is -0.555(n=5, p=0.332, pronounced negative linear relationship)), and <TEX>$-0.15mg/m^2/hr$</TEX> (second day, -0.915(n=5, p=0.030, strong negative linear relationship)) on both measurement days. The emitted flux after low tide on both measurement days reached a minimum of <TEX>$+0.00mg/m^2/hr$</TEX> (+0.713(n=5, p=0.176, linear relationship which can be almost ignored)), and a maximum of <TEX>$+0.03mg/m^2/hr$</TEX> (+0.194(n=5, p=0.754, weak positive linear relationship)) after low tide. However, the absolute values of the <TEX>$CH_4$</TEX> fluxes were analyzed at different times. These results suggest that rate for <TEX>$CH_4$</TEX> fluxes, even the same time and area, were influenced by changes in the tidal cycle characteristics of surface sediments for understanding their correlation with these gas emissions, and surrounding parameters such as physiochemical sediments conditions.

Population dynamics in canopy gaps: nonlinear response to variable light regimes by an understory plant

Gap-dependent species are typically understood to have higher population growth rates (λs) when they are exposed to higher light transmittance. I investigated the relationship between both diffuse light and direct light transmittance and λ for the gap-dependent plant Trollius laxus using 5 years of data from 20 subpopulations (11 in created, experimental canopy gaps; 9 in intact canopy control areas). There was a nonlinear (unimodal) relationship between diffuse light and λ for T. laxus under the wide range of light levels encountered at the gap and control subpopulations [4–58 % diffuse photosynthetic photon flux density (PPFD)]. There was no relationship between direct light and λ. However, in the gaps, where light levels were generally greater than 20 % PPFD, both diffuse light and direct light had strong negative linear relationships with λ. Therefore, under wide-ranging light regimes, plant populations may show complicated, nonlinear responses to gap formation. Furthermore, gap-dependent plant populations may even decline in the brightest gaps. These results demonstrate that future studies on forest plant population dynamics should strive to include populations from a wide variety of light regimes, and avoid broadly categorizing light regimes as simply “gap” or “non-gap.”

Projected Risk of Population Declines for Native Fish Species in the Upper Mississippi River

SummaryConservationists are in need of objective metrics for prioritizing the management of habitats. For individual species, the threat of extinction is often used to prioritize what species are in need of conservation action. Using long‐term monitoring data, we applied a Bayesian diffusion approximation to estimate quasi‐extinction risk for 54 native fish species within six commercial navigation reaches along a 1350‐km gradient of the upper Mississippi River system. We found a strong negative linear relationship between quasi‐extinction risk and distance upstream. For some species, quasi‐extinction estimates ranged from nearly zero in some reaches to one in others, suggesting substantial variability in threats facing individual river reaches. We found no evidence that species traits affected quasi‐extinction risk across the entire system. Our results indicate that fishes within the upper Mississippi River system face localized threats that vary across river impact gradients. This suggests that conservation actions should be focused on local habitat scales but should also consider the additive effects on downstream conditions. We also emphasize the need for identification of proximate mechanisms behind observed and predicted population declines, as conservation actions will require mitigation of such mechanisms. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Effect of Age on MRI Phase Behavior in the Subcortical Deep Gray Matter of Healthy Individuals

It has been demonstrated that increased levels of iron in the brain occur with aging. In this study we investigated the nature of the association between age and SWI-filtered phase values, indicative of iron content, in the subcortical deep gray matter of healthy individuals. A total of 210 healthy individuals (men: n = 89, women: n = 121), mean age, 39.8 years (standard deviation = 15.5; range = 6-76 years), were imaged on a 3T scanner. Mean MRI phase, mean phase of low-phase voxels, and normalized volumes were determined for total subcortical deep gray matter, caudate, putamen, globus pallidus, thalamus, pulvinar nucleus, hippocampus, amygdala, nucleus accumbens, red nucleus, and substantia nigra. Linear and nonlinear regression models were used to explore the relationship between phase and volume measures, and aging. Mean phase values of subcortical deep gray matter structures showed a quadratic relationship, with individuals in late middle age (40-59 years) having the lowest mean phase values, followed by a reversal of this trend in the elderly. In contrast, mean phase of low-phase voxel measurements showed strong negative linear relationships with aging. Significantly lower phase values were detected in women compared with men (P < .001), whereas no sex differences were observed for mean phase of low-phase voxels. Normalized volume measurements were also linearly related to aging, and women showed smaller normalized volumes of subcortical deep gray matter structures than men (P < .001). Lower mean phase of low-phase voxels was related to decreased volume measures. A strong association between phase (quadratic effect; phase decreases are followed by increases), mean phase of low-phase voxels (linear effect), volume (linear effect), and age was observed. Low phase was related to brain atrophy.

Nitrogen uptake and leaching loss of thirteen temperate grass species under high N loading

AbstractThe intensification of grazed pasture systems in New Zealand has resulted in increased nitrate () leaching and associated significant reductions in water quality, resulting from high N loading in the cow urine patch. A glasshouse soil column experiment was conducted at Lincoln University examining the N uptake capacities and leaching losses of sixteen commercial and ‘weed’ pasture grasses, comprising thirteen species. Three dairy cow urine N treatments (N loading rates) were applied in May 2010: 0 (N0), 300 (N300) and 700 (N700) kg N ha−1. Grass was harvested at 21‐d intervals, leachates collected to quantify N leaching losses and root mass measured. Shoot yield, root mass, N uptake and N leaching loss varied significantly between species (P &lt; 0·001) and were strongly driven by N loading rate. The highest yielding species at N700 were Lolium multiflorum ‘Feast 2’ and ‘Tama’ (782 and 743 g DM m−2), while Festuca arundinacea ‘Flecha’ and Lolium perenne ‘Alto' were lowest yielding (375 and 419 g DM m−2). Plant N uptake and root mass followed a similar trend, and only moderate increases in total plant N uptake were observed for most species when urine N application rate was increased from N300 to N700. N leaching loss was highest at N700 for F. arundinacea ‘Flecha’ (378 kg N ha−1) and lowest for L. multiflorum ‘Feast 2’ and ‘Tama’ (134 and 130 kg N ha−1). Strong negative linear relationships were observed between N leaching loss, plant N uptake and root mass. The results indicate that species such as L. multiflorum may play a critical role in reducing pasture N leaching losses, while traditionally sown L. perenne, and also F. arundinacea, may be less suitable.

Detailed Analysis of the Construction, Operating, Maintenance, and Rehabilitation Costs of Green Toronto Schools

AbstractThe lack of quantitative data relating initial investment to long-term costs has raised concerns about green buildings’ long-term economic effectiveness. This study analyzed the operating, maintenance, rehabilitation, and total costs of 10 conventional, 20 energy-retrofitted, and three green Leadership in Energy and Environmental Design Toronto schools over 8 years. Although green schools’ operating, maintenance, rehabilitation, and total costs were 17, 20, 32, and 25% lower than conventional schools’ costs, respectively, the statistical analysis showed no statistically significant difference in these costs between conventional, energy-retrofitted, and green schools. There was a strong negative linear relationship between schools’ operating costs and age and a strong positive relationship between schools’ maintenance and rehabilitation costs. Results also showed statistically significant linear increases in maintenance and rehabilitation costs over time in conventional and energy-retrofitted schoo...

Impacts of landscape structure on surface urban heat islands: A case study of Shanghai, China

Urbanization is taking place at an unprecedented rate around the world, particularly in China in the past few decades. One of the key impacts of rapid urbanization on the environment is the effect of urban heat island (UHI). Understanding the effects of landscape pattern on UHI is crucial for improving the ecology and sustainability of cities. This study investigated how landscape composition and configuration would affect UHI in the Shanghai metropolitan region of China, based on the analysis of land surface temperature (LST) in relation to normalized difference vegetation index (NDVI), vegetation fraction (Fv), and percent impervious surface area (ISA). Two Landsat ETM+ images acquired on March 13 and July 2, 2001 were used to estimate LST, Fv, and percent ISA. Landscape metrics were calculated from a high spatial resolution (2.5 × 2.5 m) land-cover/land-use map. Our results have showed that, although there are significant variations in LST at a given fraction of vegetation or impervious surface on a per-pixel basis, NDVI, Fv, and percent ISA are all good predictors of LST on the regional scale. There is a strong negative linear relationship between LST and positive NDVI over the region. Similar but stronger negative linear relationship exists between LST and Fv. Urban vegetation could mitigate the surface UHI better in summer than in early spring. A strong positive relationship exists between mean LST and percent ISA. The residential land is the biggest contributor to UHI, followed by industrial land. Although industrial land has the highest LST, it has limited contribution to the overall surface UHI due to its small spatial extend in Shanghai. Among the residential land-uses, areas with low- to-middle-rise buildings and low vegetation cover have much high temperatures than areas with high-rise buildings or areas with high vegetation cover. A strong correlation between the mean LST and landscape metrics indicates that urban landscape configuration also influences the surface UHI. These findings are helpful for understanding urban ecology as well as land use planning to minimize the potential environmental impacts of urbanization.

Detecting marine intrusion into rivers using EO-1 ALI satellite imagery: Modaomen Waterway, Pearl River Estuary, China

Because of increasing marine intrusion into the Pearl River Estuary (PRE) in China, salinity has become one of the important and necessary hydrological and water quality monitoring parameters. In this research, we examined the relationships between the reflectance from Earth Observing-1 (EO-1) Advanced Land Imager (ALI) satellite imagery and total suspended solids (TSS) based on the synchronous in situ spectra analysis of the river water, in an attempt to detect salinity using remote sensing technique. The study site was the Modaomen Waterway in the PRE, Guangdong Province, China. We found a strong negative linear relationship between in situ reflectance at 549 nm and TSS concentrations (R 2 = 0.91, p < 0.001) when the salinity of the river was less than 1.46‰. It indicates that the TSS near Pinggang and Nanzhen in Modaomen Waterway of PRE tends to be dominated by organic mater carried by the particles and this is one major reason for the inverse relation between reflectance and TSS. Meanwhile, a strong correlation was observed between salinity and TSS (R 2 = 0.70, p < 0.001). The salinity-TSS model accounted for 70% of variation in salinity and allowed the estimation of salinity with a root mean square error (RMSE) of less than 0.036‰ when the TSS concentrations were between 7.4 and 28 mg l−1. Therefore, we were able to develop a new method of detecting surface salinity of the river estuary from the calibrated EO-1 ALI reflectance data. The EO-1 ALI derived surface salinity and TSS concentrations were validated using in situ data that were collected on 18 December 2005, synchronous with EO-1 ALI satellite imagery acquisition. The results showed that the semi-empirical relationships are capable of deducing the TSS concentrations and then salinity from EO-1 ALI imagery in the PRE under low salinity. The methodology of detecting salinity from ALI imagery provides potential to monitor coastal saltwater intrusion and provides the water supply and conservancy authorities with useful spatial information to spatially understand and manage the marine intrusion.

Response of Ammonia Assimilation in Cucumber Seedlings to Nitrate Stress

The influence of increased nitrate concentration—14 (control) and 140 mmol L−1 (T)—in hydroponic culture on ammonia assimilation in cucumber (Cucumis sativus L. cv. Xintaimici) seedlings was investigated. The results showed that NH3 accumulation in the roots and leaves of T seedlings increased significantly, indicating that NH3 toxicity might be involved in nitrate stress. Under control conditions, GS and GOGAT activity were much higher in the leaves than in the roots, whereas GDH activity was much higher in the roots than in the leaves. Correlation analysis showed that NH3 concentration had a strong negative linear relationship with GDH activity in the roots but had a strong negative linear relationship with GS and GOGAT activity in the leaves. These results indicate that NH3 might be assimilated primarily via GDH reaction in the roots and via GS/GOGAT cycle in the leaves. Short-term nitrate stress resulted in the increase of GS and GOGAT activity in the roots and GDH activity in the leaves of T seedlings, indicating possible shifts in ammonia assimilation from the normal GDH pathway to GS/GOGAT pathway in the roots and from the normal GS/GOGAT pathway to the GDH pathway in the leaves under nitrate stress, but with the increase of treatment time, GS, GOGAT, and GDH activity in the roots and leaves of T seedlings decreased possibly due to low water potential and NH3 toxicity.