Average Date Research Articles

Changes in Serum Creatinine Levels and Natural Evolution of Acute Kidney Injury with Conservative Management of Hemodynamically Significant Patent Ductus Arteriosus in Extremely Preterm Infants at 23-26 Weeks of Gestation.

Changes in kidney function in extremely preterm infants (EPT) with conservatively managed hemodynamically significant (HS) patent ductus arteriosus (PDA) are not known well. We aimed to present the postnatal course in serum creatinine levels (sCr), prevalence of acute kidney injury (AKI), then relevance between AKI and adverse outcomes in EPT with conservatively managed HS PDA. By review of medical records, we analyzed the postnatal course of sCr and prevalence of stage 3 AKI defined by the modified Kidney Disease Improving Global Outcome (KDIGO) in EPT at gestational age of 23 to 26 weeks with conservatively treated HS PDA. We investigated if the presence and/or prolonged duration of stage 3 AKI elevated the risk of adverse outcomes. The results showed that, neither factor was associated with adverse outcomes. While the average PDA closure date was at postnatal day (P) 41 and 53, sCr peaked at P 10 and 14 and the cumulative prevalence of stage 3 AKI was 57% and 72% in the EPT of 25–26 and 23–24 weeks’ gestation, respectively. The high prevalence of stage 3 AKI without adverse outcomes in EPT with conservatively managed HS PDA suggests that it might reflect renal immaturity rather than pathologic conditions.

532 Early Debridement and Cultured Allogenic Keratinocyte Dressing Prevent Hypertrophic Scarring in Infants with Deep Dermal Burns

Abstract Introduction Deep dermal burns are frequently treated with excision and skin grafting. Otherwise, wound healing may take up to 4 to 6 weeks, with serious scarring. Especially in pediatric patients, post-burn scarring could result in psychologic trauma and functional disability. We aimed to investigate the efficacy of early debridement and dressing using cultured allogenic keratinocytes in infants with deep dermal burns to prevent hypertrophic scarring. Methods From April 2016 to April 2018, 18 infants were treated for deep dermal burns. Except for 5 infants who underwent skin grafting or excision, 13 infants were included in this study. We performed early debridement in these patients using Hydrosurgery device and serial dressings using cultured allogenic keratinocytes. Results The average operative date was 8.3 days after the accident. The mean healing time was 18.3 days after the accident. The patients did not experience any contraction, but 3 patients had hyperpigmentation, 2 patients had mild hypertrophic scarring, and 1 patient had mixed pigmentation (hyperpigmentation and hypopigmentation). Conclusions Our prophylactic scar therapy, using early debridement with VersajetTM and dressings with Kaloderm®, may be beneficial for infants with dermal burns. This method was able to shorten the healing time, resulting in better scar outcomes. Our follow-up findings revealed that the scars had an aesthetically pleasing appearance and patients were able to perform normal activities without restrictions. Applicability of Research to Practice Burn scars are painful regardless of their seriousness. They restrict the function of the body, are aesthetically unappealing, and may feel unpleasant. Patients with a post-burn scar may have aesthetic, functional, and psychological problems. In particular, infant patients experience difficulties due to scarring as they grow up.

Seasonal Population Patterns of a New Scale Pest, Acanthococcus lagerstroemiae Kuwana (Hemiptera: Sternorrhynca: Eriococcidae), of Crapemyrtles in Texas, Louisiana, and Arkansas.1

Abstract The crapemyrtle bark scale, Acanthococcus lagerstroemiae, is an invasive scale insect pest of crapemyrtles. Crawler populations were monitored using double-sided sticky tape on established crapemyrtle trees in Tyler (TX), Huntsville (TX), Dallas (TX), College Station (TX), Shreveport (LA), and Little Rock (AR) from 2015 - 2017 to determine crawler activity and determine if degree-day models could predict the first peak in crawler activity. Difference in crawler densities on upper and lower branches of trees was also determined by using double-sided sticky tapes. The first peak in crapemyrtle bark scale crawler activity was between March 26th and May 22nd across all locations and years, with multiple subsequent peaks per season frequently found, suggesting multiple generations. Using the average date (May 2nd) to predict the first peak crawler activity resulted in the lowest variance and was subsequently considered a better predictor compared to any degree-day model. There was no apparent difference in crawler activity between upper and lower branches of crapemyrtle trees across an entire season. This study provides the first set of population dynamics data for crapemyrtle bark scale in the U.S. and will help with future bark scale management decisions. Index words:, Crapemyrtle bark scale, invasive insect, population dynamics, Lagerstroemia spp Species used in this study: Crapemyrtle bark scale (Acanthococcus lagerstroemiae Kuwana); Crapemyrtle (Lagerstroemia spp.)

Rules of Thumb versus Industry Glide Paths: Some Bootstrapping Evidence

The authors compare the performance of retirement portfolios using the average glide path of five popular target date funds to general rules of thumb for asset allocation. Surprisingly, the industry average target date fund has similar return and risk as the “120 minus your age rule”. In addition, a simple “140 minus your age rule” produces greater expected savings at retirement and a lower failure rate for average US investors retiring in their early 60s. A naive approach such as the “120 minus your age” rule or the “140 minus your age” can benefit average US employees by reducing transaction costs, improving retirement balances and increasing the probability of a comfortable retirement through an easy-to-understand investing rule. TOPICS:Wealth management, retirement, performance measurement, portfolio construction Key Findings • Rule of thumb asset allocation strategies such as 120 minus your age rule and 140 minus your age rule are superior to the industry average glide path in terms of retirement balances and failure rates. • Target date fund glide paths tend to perform better than rules of thumb only for investors retiring in their late 60s and receiving social security payments or those willing to take a reduction in their retirement income. • Rule of thumb strategies are easy to understand and save transaction costs over an average industry glide path.

Mesozoic denudation history of the lower Orange River and eastward migration of erosion across the southern African Plateau

Abstract Topographic uplift of the southern African Plateau is commonly attributed to mantle causes, but the links between mantle processes, uplift, and erosion patterns are not necessarily straightforward. We acquired apatite (U-Th)/He (AHe) dates from eight kimberlite and basement samples from the lower reaches of the large westward-draining Orange River system with the goal of evaluating the roles of lithospheric modification and river incision on the erosion history here. Average AHe dates range from 79 to 118 Ma and thermal history models suggest that most samples are consistent with a main erosion phase at ca. 120–100 Ma, with some variability across the region indicating a complex erosion history. Major erosion overlaps with the timing of strong lithospheric thermochemical modification as recorded in xenoliths from the studied kimberlites, but the denudation pattern does not mimic the northward progression of lithospheric alteration across the study region. We attribute this area’s denudation history to a combination of mantle effects, rifting, establishment of the Orange River outlet at its current location, and later faulting. When considering these results with other kimberlite-derived surface histories from an ∼1000-km-long E-W transect across the plateau, an eastward-younging trend in denudation is evident. The interplay of mantle processes and the shape of the large, west-draining Orange River basin likely control this first order-pattern.

Shifts in hatching date of American crocodile (Crocodylus acutus) in southern Florida.

Globally temperature of marine environments is on the rise and temperature plays an important role in the life-history of reptiles. In this study, we examined the relationship between sea surface temperature and average date of hatching for American crocodiles (Crocodylus acutus) over a 37-year period at two nesting sites, Everglades National Park and Florida Power and Light Turkey Point Power Plant site in southern Florida. Our results indicate that hatch dates are shifting 1.5 days earlier every two years and at half that rate for the Turkey Point site, and with every 1°C degree increase in temperature, hatching occurs about 10 days earlier in the Everglades and 6 days earlier at Turkey Point. Our results on shifting hatch dates for American crocodiles provide further details about the impacts of temperature change on crocodile life history and suggest that increased temperature may affect their phenology.

Can climatic variables improve phenological predictions for butterfly species?

Changes in butterfly phenology due to climate changes have led to the need for models based on factors other than calendar date to predict butterfly development, allowing those monitoring their populations to increase the effectiveness of field surveys. In this study, we developed two simple climatic models, one using yearly accumulated growing degree days (GDD) and the other using yearly accumulated shortwave radiation flux densities (SRAD), to determine if these variables can predict first emergence of three butterfly species with less error than an approach based on the average ordinal date of first observation at a site. Furthermore, we investigated whether combining our two models would increase our ability to predict the timing of first emergence. We determined that GDD models were better at predicting first emergence than were ordinal date models and SRAD models for all species tested; however, the actual variation among these models was so small that any additional effort required to develop GDD models would not justify their use as a replacement for the simpler ordinal date models at this time, although as climate changes they may become more useful. We also determined that combined models did not improve the ability to predict first emergence.

Evaluation of Preclinical and Clinical Studies Published in Medical Journals of Bosnia and Herzegovina: Methodology Issues.

Introduction:Results of preclinical and clinical studies in medicine could be trusted only if their design and statistical analysis were appropriate.Aim:The aim of our study was to investigate whether preclinical and clinical studies published in medical journals of Bosnia and Herzegovina satisfy basic requirements for appropriate design and statistical interpretation of data.Methods:Preclinical and clinical studies published in medical journals of Bosnia and Herzegovina were retrieved from the PubMed database, and the sample for analysis was randomly chosen from the retrieved publications. Implementation rate of basic principles of experimental design (local control, randomization and replication) and rate of the most common errors in design of clinical/observational studies was established by careful reading of the sampled publications and their checking against predefined criteria.Results:Our study showed that only a minority of experimental preclinical studies had basic principles of design completely implemented (7%), while implementation rate of single aspects of appropriate experimental design varied from as low as 12% to as high as 77%. Only one of the clinical/observational studies had none of the errors searched for (2%), and specific errors rates varied from 10% to 89%. Average impact factor of the surveyed studies was around one, and average publication date recent, less than 5 years ago.Conclusion:Prevalence of preclinical studies that did not follow completely basic principles of research design, and that of clinical/observational studies with errors are high, raising suspicion to validity of their results. If incorrect and not protected against bias, results of published studies may adversely influence future research.

Climate-associated trends and variability in ichthyoplankton phenology from the longest continuous larval fish time series on the east coast of the United States

As the effects of climate change become more pronounced, variation in the direction and magnitude of shifts in species occurrence in space and time may disrupt interspecific interactions in ecological communities. In this study, we examined how the fall and winter ichthyoplankton community in the Newport River Estuary located inshore of Pamlico Sound in the southeastern United States has responded to environmental variability over the last 27 yr. We relate the timing of estuarine ingress of 10 larval fish species to changes in sea surface temperature (SST), the Atlantic Multidecadal Oscillation, the North Atlantic Oscillation, wind strength and phenology, and tidal height. We also examined whether any species exhibited trends in ingress phenology over the last 3 decades. Species varied in the magnitude of their responses to all of the environmental variables studied, but most shared a common direction of change. SST and northerly wind strength had the largest impact on estuarine ingress phenology, with most species ingressing earlier during warm years and delaying ingress during years with strong northerly winds. As SST warms in the coming decades, the average date of ingress of some species (Atlantic croaker Micropogonias undulatus, summer flounder Paralichthys dentatus, pinfish Lagodon rhomboides) is projected to advance on the order of weeks to months, assuming temperatures do not exceed a threshold at which species can no longer respond through changes in phenology. These shifts in ingress could affect larval survival and growth since environmental conditions in the estuarine and pelagic nursery habitats of fishes also vary seasonally.

Flowering phenology of apricot cultivars in the Belgrade region

The phenology of flowering was studied in 50 apricot cultivars in the Belgrade region over a period of eight years (2009-2016). Within the flowering phenophase, three sub-phases were registered: the beginning of flowering, full flowering and the end of flowering. In addition, the duration and abundance of flowering were examined. The average date of the beginning of flowering for all cultivars was March 22, of full flowering - March 25, and of the end of flowering - April 1. The average duration of flowering was 9.7 days, with a range among cultivars between 7.5 days ('Gergana') and 12 days ('Ninfa ' and 'Radka'). The lowest average score (3.0) for flowering intensity was obtained in 'Hungarian Best' cultivar, and the highest score (4.6) in 'Harcot' and 'Leskora' cultivars. In years with higher temperatures during the flowering, a smaller range in flowering time among cultivars was recorded, as well as shorter duration of flowering. Based on the beginning of flowering, the tested cultivars were classified into three groups: early-flowering (14 cultivars), medium-flowering (21 cultivars) and late-flowering (15 cultivars). Meteorological factors (air temperature) had a greater influence on the course and duration of the flowering phenophase than the genetic traits of the cultivars.

Subtle differences in breeding performance between Great Tits Parus major and Afrocanarian Blue Tits Cyanistes teneriffae in the peripheral zone of the species geographic ranges in NE Algeria

Because of the geological history of North Africa, populations of Great Tits Parus major existing in this region experienced less geographical isolation from populations of continental Europe than populations of Afrocanarian Blue Tits Cyanistes teneriffae. As a result, North African Great Tits are more ephemeral in their distribution and habitat choice as well as less ecologically generalist than their European continental conspecifics. By contrast, the Afrocanarian Blue Tit forms a separate species which is closely related to the Blue Tit Cyanistes caeruleus of Europe, including Mediterranean islands. Afrocanarian Blue Tits are a versatile generalist species. Here we compare some aspects of the breeding ecology of Great Tits and Afrocanarian Blue Tits in a highland area of the Algerian Aures Mountains facing the Sahara in the south. For both the tit species this area constitutes peripheral part of their distributions. We found that in two breeding seasons Great Tits started laying eggs on similar average dates as Afrocanarian Blue Tits, whereas in one year they preceded the latter species. Great Tits laid larger clutches than Afrocanarian Blue Tits. Fledging success was similar between the two species, with Great Tits prospering slightly better in the year when broods of Great Tits were also less infested by blow flies than broods of Afrocanarian Blue Tits. The subtle differences we found between the breeding ecology of Great Tits and Afrocanarian Blue Tits seem to be consistent with Snow’s idea that these species in North Africa differ in a degree of adaptation to local conditions.

Satellite Monitoring of Temperature Conditions near the Mouths of Spawning Rivers in the Southern Part of Sakhalin Island

Ten-day mean sea surface temperature (SST) series have been collected using satellite measurements in 22 coastal regions adjacent to the river mouths of Sakhalin Island from spring to summer (May–July) in 1998–2017. Average long-term dates of the onset of favorable conditions for the release of salmon juveniles from hatcheries (+6–7°C) have been evaluated. Mean square and extreme deviations from these dates have been determined. Synoptic conditions from 2011, under which there were the greatest delays in the release of salmon from the hatcheries, are analyzed.

Effects of breeding chronology on white‐tailed deer productivity in Alabama

ABSTRACTFollowing declines in white‐tailed deer (Odocoileus virginianus) populations during the 19th century, many areas throughout the southeastern United States were restocked from various sources. As a result, some populations remain genetically distinct, and phenotypic traits of source populations, including breeding chronology, have been conserved. For example, average conception dates vary by ≥60 days between populations within some Alabama, USA, counties. Although deer have achieved and maintained sustainable densities across much of the southeastern United States for several decades, it is unclear whether this restocking legacy has demographic consequences relevant to management. Therefore, we analyzed a data set containing information on 270 yearling (1.5 yr old) and 2,116 adult (≥2.5 yr old) female deer collected during 1995–2017 to determine potential effects of breeding chronology on in utero productivity. Parameter estimates from a generalized linear mixed model indicated yearling productivity decreased approximately 16% (95% CL = 0–29%) for each 30‐day increase in mean site‐specific parturition date. We did not observe a similar relationship for adults. We believe the relationships we observed for yearlings may result from an interaction between parturition and plant phenology. Specifically, on sites with relatively late parturition dates, fawns are born near the end of the growing season when suboptimal nutritional conditions may negatively affect productivity during their first year of life. Variation in reproductive output of large ungulates is primarily driven by young females, so managers should be aware that productivity of late‐breeding deer populations may be less than average, especially if those populations are behaving in a density‐dependent manner. In addition, these findings emphasize the importance of considering the potential demographic implications of wildlife translocations resulting from differences in timing of life‐history traits. © 2019 The Wildlife Society.

A lean six sigma approach for improving university campus office moves

Purpose The purpose of this study was to improve the quoting, scheduling, invoicing and paying for campus office moves at a university. The Lean Six Sigma project goal was to improve the campus office move process by making it less complicated, free-up program managers’ time and pay the vendor on time. Design/methodology/approach The team used the Lean Six Sigma Define-Measure-Analyze-Improve-Control methodology to improve the process. Findings The average time from the campus move to when the invoice was paid improved by 27%, with an improved median of 16%. The standard deviation was greatly reduced by 51%. The average invoiced date to paid date remained statistically the same, and the median increased from 20 to 30 days, due to a policy change to move the target from 20 to 30 days. The standard deviation of the invoice to paid date was greatly reduced by 38%. This was a successful project because the sponsors were on-board from the beginning and included the process owners in the improvement effort. Originality/value Other higher education institutions or other industry areas with a similar process can implement this methodology and processes outlined in this case study to improve efficiency and cost effectiveness and as a guide for improving other processes within institutions.

Direct and indirect effects of regional and local climatic factors on trophic interactions in the Arctic tundra

Climate change can impact ecosystems by reshaping the dynamics of resource exploitation for predators and their prey. Alterations of these pathways could be especially intense in ecosystems characterized by a simple trophic structure and rapid warming trends, such as in the Arctic. However, quantifying the multiple direct and indirect pathways through which climate change is likely to alter trophic interactions and their relative strength remains a challenge. Here, we aim to identify direct and indirect causal mechanisms driven by climate affecting predator-prey interactions of species sharing a tundra food web. We based our study on relationships between one Arctic predator (Arctic fox) and its two main prey - lemmings (preferred prey) and snow geese (alternate prey) - which are exposed to variable local and regional climatic factors across years. We used a combination of models mapping multiple causal links among key variables derived from a long-term dataset (21years). We obtained several possible scenarios linking regional climate factors (Arctic oscillations) and local temperature and precipitation to the breeding of species. Our results suggest that both regional and local climate factors have direct and indirect impacts on the breeding of foxes and geese. Local climate showed a positive causal link with goose nesting success, while both regional and local climate displayed contrasted effects on the proportion of fox breeding. We found no impact of climate on lemming abundance. We observed positive relationships between lemming, fox and goose reproduction highlighting numerical and functional responses of fox to the variability of lemming abundance. Our study measures causal links and strength of interactions in a food web, quantifying both numerical response of a predator and apparent interactions between its two main prey. These results improve our understanding of the complex effects of climate on predator-prey interactions and our capacity to anticipate food web response to ongoing climate change.

Phenological performance of olive tree in a warm production area of central Tunisia

Climate changes are expected to have a great and negative impact on agriculture in Mediterranean region. In this region, olive industry plays a key role at regional and national level as in Tunisia. With expected increasing temperature, the impact of climate change on the phonological behavior of the olive cultivars was evaluated in the main production region in central Tunisia (34°56′08″N, 10°36′54″E) during 2005–2015.The relationships between the budburst and flowering dates and climatic variations were investigated for the main local (Chemlali, Chemchali, Oueslati and Chetoui) and foreign (Koroneiki and Arbequina) olive cultivars to state their adaptability to warm area climate. Chilling was computed as chill portions (CP) from October to budburst using Dynamic Model, whereas heat accumulation was quantified as growing degree hours (GDH) from budburst to the beginning of flowering. As a result, variable budburst and flowering dates of olive cultivars were obtained related to the climatic conditions occurring each year. ‘Chemlali’ and ‘Arbequina’ seemed to be the precocious cultivars with an average budburst date of DOY-71 (March-12), whereas ‘Chemchali’ and ‘Koroneiki’ were the most late with an average budburst dates of DOY-80 and DOY-81 (March21-22). The beginning of flowering occurred from DOY-93 (3-April) to DOY-126 (6-May), where ‘Chemchali’ seemed, also, to be the latest one. Winter chill impacted significantly olive flowering with a positive correlation between flowering date and chill accumulation. A tendency for advancing flowering of local and foreign olive cultivars occurred subsequent a lack of winter chill. Trends for increasing heat accumulation with increasing chilling were observed in exponential manner to achieve flowering of olive cultivars. Moreover, winter temperature, appeared to be one of the most important variables in determining flowering time of olive cultivars mainly when quarterly and monthly mean temperatures were considered. In conclusion, this investigation is the first database concerning olive cultivars originated from different geographical areas and grown in a warm area. It revealed that olive cultivars behaved differently with contrasting chilling and heat accumulations and in years with extreme climatic conditions. It will be more interesting to consider the important genetic diversity of olive tree to mitigate the harmful effect of increasing temperature in the future.

‘Bodrami’, Mid-Maturing Brown Rice Cultivar with High Grain Quality and Soft Texture Suitable for Cooking

‘Bodrami’ is a brown rice cultivar suitable for cooking, developed by crossing ‘Hwaseong’ and ‘Congsengla’ cultivars at Rural Development Administration, Korea, in 2003. Cooked brown rice of ‘Bodrami’ naturally has a soft texture, and after 24 hours of warm treatment, it maintained its soft texture and it was evaluated that the taste and texture of cooked brown rice were better than that of another rice cultivar. ‘Bodrami’ is a mid-maturing rice cultivar. The average heading date in ordinary planting was August 11th in Suwon, Korea, which also exhibits strong to blast leaf and rice stripe virus, and brown rice yield of ‘Bodrami’ had a yield of 5.56 MT/ha in ordinary planting. The advantages of eating brown rice are high intake of GABA (which is excellent for controlling blood), γ-oryzanol (which is good for Antioxidation), rice embryos (rich in fiber), and rice bran (rich in minerals). Another advantage of ‘Bodrami’ is that, compared to glutinous rice varieties (which is a higher glycemic index), it has a lower glycemic index and a smooth texture. The consumption of white rice has been decreasing recently, while interest in brown rice has been increasing as a consequence of these advantages. ‘Bodrami’ was developed in response to recent changes in consumption preferences. (Registration No. 5644)

Shortened temperature-relevant period of spring leaf-out in temperate-zone trees.

Temperature during a particular period prior to spring leaf-out, the temperature-relevant period (TRP), is a strong determinant of the leaf-out date in temperate-zone trees. Climatic warming has substantially advanced leaf-out dates in temperate biomes worldwide, but its effect on the beginning and length of the TRP has not yet been explored, despite its direct relevance for phenology modeling. Using 1,551 species-site combinations of long-term (1951-2016) in situ observations on six tree species (namely, Aesculus hippocastanum, Alnus glutinosa, Betula pendula, Fagus sylvatica, Fraxinus excelsior, and Quercus robur) in central Europe, we found that the advancing leaf-out was accompanied by a shortening of the TRP. On average across all species and sites, the length of the TRP significantly decreased by 23% (p<.05), from 60±4days during 1951-1965 to 47±4days during 2002-2016. Importantly, the average start date of the TRP did not vary significantly over the study period (March 2-5, DOY=61-64), which could be explained by sufficient chilling over the study period in the regions considered. The advanced leaf-out date with unchanged beginning of the TRP can be explained by the faster accumulation of the required heat due to climatic warming, which overcompensated for the retarding effect of shortening daylength on bud development. This study shows that climate warming has not yet affected the mean TRP starting date in the study region, implying that phenology modules in global land surface models might be reliable assuming a fixed TRP starting date at least for the temperate central Europe. Field warming experiments do, however, remain necessary to test to what extent the length of TRP will continue to shorten and whether the starting date will remain stable under future climate conditions.

The within-population variability of leaf spring and autumn phenology is influenced by temperature in temperate deciduous trees.

Leaf phenology is a major driver of ecosystem functioning in temperate forests and a robust indicator of climate change. Both the inter-annual and inter-population variability of leaf phenology have received much attention in the literature; in contrast, the within-population variability of leaf phenology has been far less studied. Beyond its impact on individual tree physiological processes, the within-population variability of leaf phenology can affect the estimation of the average budburst or leaf senescence dates at the population scale. Here, we monitored the progress of spring and autumn leaf phenology over 14 tree populations (9 tree species) in six European forests over the period of 2011 to 2018 (yielding 16 site-years of data for spring, 14 for autumn). We monitored 27 to 512 (with a median of 62) individuals per population. We quantified the within-population variability of leaf phenology as the standard deviation of the distribution of individual dates of budburst or leaf senescence (SDBBi and SDLSi, respectively). Given the natural variability of phenological dates occurring in our tree populations, we estimated from the data that a minimum sample size of 28 (resp. 23) individuals, are required to estimate SDBBi (resp. SDLSi) with a precision of 3 (resp. 7) days. The within-population of leaf senescence (average SDLSi = 8.5days) was on average two times larger than for budburst (average SDBBi = 4.0days). We evidenced that warmer temperature during the budburst period and a late average budburst date were associated with a lower SDBBi, as a result of a quicker spread of budburst in tree populations, with a strong species effect. Regarding autumn phenology, we observed that later senescence and warm temperatures during the senescence period were linked with a high SDLSi, with a strong species effect. The shares of variance explained by our models were modest suggesting that other factors likely influence the within-population variation in leaf phenology. For instance, a detailed analysis revealed that summer temperatures were negatively correlated with a lower SDLSi.

Improved Spring Vegetation Phenology Calculation Method Using a Coupled Model and Anomalous Point Detection

High temporal resolution remote sensing satellite data can be used to collect vegetation phenology observations over regional and global scales. Logistic and polynomial functions are the most widely used methods for fitting time series normalized difference vegetation index (NDVI) derived from the Moderate Resolution Imaging Spectroradiometer (MODIS). Furthermore, the maximum in the curvature of the fitted curve is usually considered as the spring green-up date. However, the existing green-up date calculation methods have low accuracy for sparse vegetation. This paper proposes an improved green-up date calculation method using a coupled model and anomalous point detection (CMAPD). This model is based on a combination of logistic and polynomial functions, which is used to fit time series vegetation index. Anomalous values were identified using the nearest neighbor algorithm, and these values were corrected by the combination of growing degree-days (GDD) and land use type. Then, the trends and spatial patterns of green-up date was analyzed in the Sanjiangyuan area. The results show that the coupled model fit the time series data better than a single logistic or polynomial function. Besides, the anomalous point detection method properly controlled the green-up date within the local threshold, and could reflect green-up date more accurately. In addition, a weak statistically significant advance trend for average vegetation green-up date was observed from 2000 to 2016. However, in 10.4% of the study area, the the green-up date has significant advanced. Regression analysis showed that the green-up date is correlated to elevation: the green-up date is clearly later at higher elevations.