Rate Of Change Research Articles

Mountain greening and rising temperatures erode habitats of ironwort (Sideritis), an important natural medicinal resource

Societal Impact StatementNative medicinal plants contribute essential health benefits to populations globally, constituting a major natural resource that human societies rely on. Being an integral part of terrestrial biodiversity, medicinal plants are detrimentally affected by ongoing climate and land‐use change, yet comprehensive studies on the risk that extinction will pose to medicinal biodiversity are lacking. Responding to ongoing scientific calls for conserving medicinal biodiversity, this study provides an integrated assessment of the impacts of environmental change on ironwort (Sideritis), a group of closely related endemic plants of great cultural significance as local medicinal resources in the Balkan Mountains.Summary Mountain habitats harbour unique biodiversity and provide vital resources for human well‐being, including natural medicinal resources, yet they are amongst the environments most impacted by global change. While there is ample evidence of recent rapid climate and land‐use change on mountain ecosystems, the impacts of these processes on the habitats of culturally important medicinal plants are still poorly understood. Here, we assess the potential loss of mountain habitats for medicinal plant resources over the past four decades using the culturally important ironwort, a group of endemic medicinal plants of the Balkan Mountains extensively used by local human populations and the pharmaceutical industry for treating cough and cold and gastrointestinal disorders. We used information collected from major European natural history museums to guide extensive field campaigns across 15 separate mountain ranges. We integrate field data with thousands of satellite images, station‐validated climate reanalysis data and habitat suitability modelling. We finally used machine learning to assess the relative roles of climate and vegetation rates of change in driving rates of habitat suitability change. We show that rising temperatures and ‘mountain greening’ erode the habitats of ironwort at alarming rates. About 50% of the total habitat area across all considered mountain ranges shows a significant decline in habitat suitability. These past trends will most likely continue in the future and could lead to widespread local extinction of the species and other medicinal plants that share similar ecological preferences, threatening their future contributions to societal well‐being.

Optimizing Implant Width Selection in Breast Augmentation: Insights from On-Patient Landmark Positioning in 3D Breast Simulation.

The VECTRA® XT 3D simulation program is a valuable tool for implant selection during the decision-making process of breast augmentations. The software allows for the assignment of automatically or manually positioned anatomical landmarks and provides accompanying measurements. This study aimed to present a strategy for standardizing landmark placement on Vectra® images during primary breast augmentations, optimize implant selection, and insure consistency in breast width data collection. We performed a retrospective analysis of patient data wherein breast width measurements were obtained through Clinical Assessment (CA) and the Vectra® program using both automatically (VA) and manually (VM) placed landmarks. Consideration was also given to the thickness of medial and lateral breast tissues. The suggested implant base width from all groups was then compared to the actual implant (AI) used during surgical procedures. Comparing the change rates in relation to the actual implant width revealed that rates in CA measurements were significantly lower than those in VA (p < 0.05), and similarly lower than those in VM (p < 0.05). Furthermore, change rates in VM were significantly lower than in VA (p < 0.05). Each group showed a significant positive correlation with the actual implant width. The Vectra® XT 3D simulation program is a valuable adjunct in breast augmentation. However, relying on it solely may lead to inaccuracies in the assessment of breast dimensions due to automatic landmarking. To achieve standardized measurements, landmarks can be marked on the patient before creating the Vectra® image. Our results underline the superiority of clinical judgment over simulation programs in establishing a reliable surgical plan.

Patterns of recovery in extant and extirpated seabirds after the world's largest multipredator eradication.

Eradicating invasive predators from islands can result in substantial recovery of seabirds, but the mechanisms that drive population changes remain poorly understood. Meta-analyses have recently revealed that immigration is surprisingly important to the recovery of philopatric seabirds, but it is not known whether dispersal and philopatry interact predictably to determine rates of population growth and changes of distribution. We used whole-island surveys and long-term monitoring plots to study the abundance, distribution, and trends of 4 burrowing seabird species on Macquarie Island, Australia, to examine the legacy impacts of invasive species and ongoing responses to the world's largest eradication of multiple species of vertebrates. Wekas (Gallirallus australis) were eradicated in 1988; cats (Felis catus) in 2001; and rabbits (Oryctolagus cuniculus), black rats (Rattus rattus), and mice (Mus mus) in 2011-2014. We compared surveys from 1976-1979 and 2017-2018 and monitoring from the 1990s and 2000s onward. Antarctic prions (Pachyptila desolata) and white-headed petrels (Pterodroma lessonii) increased ∼1% per year. Blue petrels (Halobaena caerulea) and gray petrels (Procellaria cinerea) recolonized following extirpation from the main island in the 1900s but remained spatially and numerically rare in 2018. However, they increased rapidly at 14% and 10% per year, respectively, since cat eradication in 2001. Blue and gray petrel recolonization occurred on steep, dry, west-facing slopes close to ridgelines at low elevation (i.e., high-quality petrel habitat). They overlapped <5% with the distribution of Antarctic prion and white-headed petrels whichoccurred in suboptimal shallow, wet, east-facing slopes at high elevation. We inferred that the speed of population growth of recolonizing species was related to their numerically smaller starting size compared with the established species and was driven by immigration and selection of ideal habitat.

Global trends in the incidence and prevalence of pneumoconiosis in 204 countries/territories from 1990 to 2019

Objective: To analyze the changing trend of incidence and prevalence of pneumoconiosis globally, and provide scientific basis for the formulation of health policy. Methods: In June 2022, through the Global Health Data exchange (GHDx) query tool (http: //ghdx.healthdata.org/gbd-results-tool) , the pneumoconiosis incidence and prevalence data was downloaded and organized. Estimated annual percentage change (EAPC) and age-standardized rate (ASR) were used to estimate the trends of pneumoconiosis from 1990 to 2019. EAPC was estimated by linear regression model based on ASR. Results: The overall ASR of the incidence and prevalence of pneumoconiosis decreased from 1990 to 2019, and their EAPCs were-0.85% (95%CI: -1.11%--0.60%) and -0.78% (95%CI: -1.08%--0.49%) . Over the past 30 years, the incidence and prevalence of pneumoconiosis in all SDI areas showed decreasing trends, especially in high SDI areas, their EAPCs were -1.46% (95%CI: -1.76%--1.15%) and -1.99% (95%CI: -2.44%--1.53%) . 110 countries/areas showed increasing trends in age standardized incidence rate (ASIR) , with Iran and Georgia showing the most pronounced upward trend, their EAPCs were 5.32% (95%CI: 4.43%-6.22%) and 4.39% (95%CI: 3.81%-4.97%) . 125 countries/areas showed anincreasing trends in prevalence ASR, with Iran had the fastest rise in prevalence (EAPC=6.40%, 95%CI: 5.33%-7.49%) . Conclusion: Although decreasing trends in the burden of pneumoconiosis are observed globally from 1990 to 2019, but the burden of pneumoconiosis in low-and middle-income countries or regions are still heavy. We need more effective strategies to prevent and reduce the burden of pneumoconiosis.

True pattern-reversal LED stimulator and its comparison to LCD and CRT displays: visual evoked potential study

A rapid checkerboard pattern change is used to elicit pattern-reversal visual evoked potentials (PR VEPs). CRT or LCD monitors do not allow immediate reversal of the entire pattern. The study aimed to construct a new stimulator whose characteristics approximate an instantaneous reversal and verify whether the improvement is reflected in PR VEPs. A new stimulator using a matrix of 12 × 48 independent white square LEDs was designed and compared with LCDs and CRTs. The effect on the PR VEP peak times and amplitudes of N70, P100, and P140 waves was evaluated in ten subjects. The LED stimulator showed significantly better performance in the rate of change of illuminance, change of pattern, luminance settling and stability. The PR VEP amplitudes of N75, P100, and N140 did not show significant differences. The sum of interpeak amplitudes was significantly larger for the LCD than for the other monitors. The peak times of the waves evoked by the LED were shorter than those evoked by the LCD and CRT for the N75 wave and a check size of 30´. LED stimulators are a better alternative to CRTs for PR VEPs than current LCDs. LEDs also seem to be better than CRTs, but further research is necessary to obtain significant results.

Photochemical characterization of rate laws, rate constants and photonicities in optically–dense, multiphoton–reactive systems

A novel method for characterizing the rate constants k and photonicities n of multiphoton–induced reactions in optically dense media is presented. Conventionally, k and n are calculated by irradiating samples of identical absorbance with different incident initial intensities I0,0 and characterizing the rates of change in absorbance, with incident rate constants k0,0 being proportional to I0,0n for n–photon processes. In our method,I0,0n is replaced by a longitudinally–and–temporally–averaged nth–order intensityIx,tn¯=1-10-nA¯2.303nA¯I0,0n which accounts for the exponential decrease in intensity across the optical pathlength due to the average absorbance A¯ over an irradiation interval of duration t.We demonstrate the utility of Ix,tn¯ by contrasting longitudinally–and–temporally–averaged rate constants kx,t and photonicities nx,t with incident rate constants k0,0 and photonicities n0,0 for the 532 nm, two–photon induced photodegradation of β–carotene in CCl4 solvent. Because the actinic intensity declines more rapidly with x in high (A ∼ 1.0) than low (A ∼ 0.2) absorbance samples, the incident rates R0,0=k0,0I0,0n are faster in the low absorbance samples: i.e., k0,0(A532 = 0.2) > k0,0(A532 = 1.0). In significant contrast, we find that kx,t(A532 = 1.0) ∼ kx,t(A532 = 0.2). indicating that kx,t provides better estimates of the rate constant than k0,0. As with kx,t, we find that the photonicities are minimally affected by A532; i.e., n0,0 ∼ nx,t for both low and high absorbance samples. Hence, the dependence of the rate on the actinic absorbance is incorporated principally into the incident rate constants k0,0; kx,t, n0,0 and nx,t are largely unaffected by A532. We detail potential applications of our method to both multiphoton–induced chemical synthesis and multiphoton–induced photodynamic therapy scenarios, as high absorbance samples are advantageous for both of these applications.

A high-resolution calving front data product for marine-terminating glaciers in Svalbard

Abstract. The mass loss of glaciers outside the polar ice sheets has been accelerating during the past several decades and has been contributing to global sea-level rise. However, many of the mechanisms of this mass loss process are not well understood, especially the calving dynamics of marine-terminating glaciers, in part due to a lack of high-resolution calving front observations. Svalbard is an ideal site to study the climate sensitivity of glaciers as it is a region that has been undergoing amplified climate variability in both space and time compared to the global mean. Here we present a new high-resolution calving front dataset of 149 marine-terminating glaciers in Svalbard, comprising 124 919 glacier calving front positions during the period 1985–2023 (https://doi.org/10.5281/zenodo.10407266, Li et al., 2023). This dataset was generated using a novel automated deep-learning framework and multiple optical and SAR satellite images from Landsat, Terra-ASTER, Sentinel-2, and Sentinel-1 satellite missions. The overall calving front mapping uncertainty across Svalbard is 31 m. The newly derived calving front dataset agrees well with recent decadal calving front observations between 2000 and 2020 (Kochtitzky and Copland, 2022) and an annual calving front dataset between 2008 and 2022 (Moholdt et al., 2022). The calving fronts between our product and the latter deviate by 32 ± 65 m on average. The R2 of the glacier calving front change rates between these two products is 0.98, indicating an excellent match. Using this new calving front dataset, we identified widespread calving front retreats during the past four decades, across most regions in Svalbard except for a handful of glaciers draining the ice caps Vestfonna and Austfonna on Nordaustlandet. In addition, we identified complex patterns of glacier surging events overlaid with seasonal calving cycles. These data and findings provide insights into understanding glacier calving mechanisms and drivers. This new dataset can help improve estimates of glacier frontal ablation as a component of the integrated mass balance of marine-terminating glaciers.

Demand-side and supply-side factors for accelerating varietal turnover in smallholder soybean farms

The rapid growth of soybean cultivation in the world augurs well for achieving SDG2 of promoting sustainable agriculture, ending hunger, achieving food security, and improving nutrition. India started promoting soybean cultivation in the 1970s to combat dietary protein deficiencies and augment smallholders' incomes. However, soybean yield remains low and plateaued at one ton per hectare for the past three decades. This paper leverages a large primary dataset and explores the speed of soybean varietal change by applying survival functions and analyzing determinants of varietal turnover time employing a dynamic framework and harnessing duration analysis. The results show that adopting leading soybean varieties has reached saturation and that policy intervention can have an immediate impact. The weighted average age of soybean varieties in farmers' fields is relatively high at 15.6 years, implying a slower varietal change rate. The lack of improved varieties with desirable traits, poor information flow, and growers’ preference for traits beyond yield-hamper faster varietal substitution. Further, analysis indicates regional variations in driving the speed of varietal replacement. The findings have significant implications for spurring soybean yields through investments in varietal development, leveraging modern molecular methods for long juvenility and photo-insensitivity, disseminating information, and institutional changes enabling the private sector participation in crop breeding.

Numerical Methods for Option Pricing

Nowadays, financial markets have become more complex and have given rise to more research opportunities, one of which focuses on research related to the pricing of various financial instruments used in options trading. In this essay, a gradual process of reflection is used to deepen the option pricing theory. Firstly, an effective mathematical method for pricing option contracts is using the binomial tree model, a relatively straightforward way of calculating the value of an option. However, it has only two upward and downward trends and has limitations that are the most different from the actual market conditions. That is why the study will have to continue in-depth to get as close as possible to the real situation in the market. The next step is to make the model more in line with market reality by adding a possible rate of change, resulting in the Trinomial Tree Model. The model incorporates the possibility of future price increases, decreases, or stabilization (the third change). The Trinomial Tree Model follows the no-arbitrage principle and removes the assumption of a risk-free market opportunity. This paper derives a method for constraining market prices under risk-neutral conditions. This is crucial for investors seeking profitable outcomes in options trading. The main objective of this research-based paper is to develop a complete theory of option pricing in a one-step trinomial tree model.

Land Cover Changes and Driving Factors in the Source Regions of the Yangtze and Yellow Rivers over the Past 40 Years

As a climate-sensitive region of the Tibetan Plateau, the source regions of the Yangtze and Yellow Rivers (SRYYRs) urgently require an analysis of land cover change (LUCCs) over a long period, high temporal resolution, and high spatial resolution. This study utilizes nearly 40 years of land cover, the Normalized Difference Vegetation Index (NDVI), climate, and geomorphological data, applying methods including a land transfer matrix, slope trend analysis, correlation analysis, and landscape pattern indices to analyze the spatial and temporal changes, composition, layout, and quality of the local land cover and the factors. The findings reveal that (1) the land cover area change rate was 8.96% over the past 40 years, the unutilized land area decreased by 24.49%, and the grassland area increased by 6.37%. The changes were obvious at the junction of the two source regions and the southeast side of the source region of the Yellow River. (2) the landscape pattern was more centralized and diversified. The number of low-cover grassland patches increased by 12.92%. (3) The region is still dominated by medium- and low-cover vegetation, with the mean annual NDVI increasing at a rate of 0.006/10a, and the rate of change after 2000 is three times higher than previously. (4) The degree of land cover change is greater in the middle altitudes, semisunny aspects, steepest slopes, and middle-relief mountains. Additionally, 76.8% of the region’s vegetation growth is dominated by mean annual temperatures. This study provides fundamental data and theory for understanding LUCCs and the driving factors in alpine plateau regions.

Variable‐volume accelerated system to evaluate the carbaryl biodegradation dynamics of a microbial community by differential analysis

AbstractBACKGROUNDOne of the continuous cultivation methods for acquiring quantitative data on microbial metabolism under various environmental conditions within a single experiment is the accelerostat culture system (A‐stat). It allows the rapid analysis and quantitative evaluation of the effect of environmental on the functional response of microorganisms, which is reflected by the cultural biokinetic parameters. In a classical accelerostat system, equipment and control programs maintain a constant acceleration (a) of the culture's dilution rate D[t] = Do + at. Unlike the conventional A‐stat, in which a linear change in the dilution rate is obtained, a new variant, here named a variable‐volume accelerated (VVA) system, the acceleration is variable (a = f[t]); thus, D[t] = Do + a[t]. This system requires minimal manual intervention and presents operational advantages over the classical A‐stat; the reactor's D[t] change is achieved under a simple condition: the input and output flow rates are unequal; Fin ≠ Fout.RESULTSUsing carbaryl as a study model, the dynamic behavior of the VVA system was evaluated by differential analysis of the experimental data obtained by cultivating a carbaryl‐degrading microbial community. Mathematical analysis of the VVA system established the acceleration profile a[t] for the study, quantifying the impact of dilution rate on the microbial community's biokinetic and stoichiometric parameters.CONCLUSIONThe VVA system allowed observation of the effect of the D[t] gradient on the rate of change of kinetic parameters that define the physiological state of the microbial culture, together with the microbial community's macromolecular composition. © 2024 Society of Chemical Industry (SCI).

Predicting the impact of temperature and relative humidity on Salmonella growth and survival in sliced chard, broccoli and red cabbage

This study assessed the fate of a Salmonella enterica cocktail (S. Typhimurium, S. Enteritidis, S. Newport, S. Agona and S. Anatum; initial counts 3.5 log CFU/g) in minimally processed sliced chard, broccoli and red cabbage at 16 conditions of different temperature (7, 14, 21 and 37 °C) and relative humidity (RH; 15, 35, 65 and 95%) over six days (144 h). Linear regression was used to estimate the rate change of Salmonella in cut vegetables as a function of temperature and relative humidity (RH). R2 value of 0.85, 0.87, and 0.78 were observed for the rates of change in chard, broccoli, and red cabbage, respectively. The interaction between temperature and RH was significant in all sliced vegetables. Higher temperatures and RH values favored Salmonella growth. As temperature or RH decreased, the rate of S. enterica change varied by vegetable. The models developed here can improve risk management of Salmonella in fresh cut vegetables.

Clinical and radiographic outcomes of lateral sinus floor elevation with simultaneous hydrophilic implants placement: A retrospective study of 2-5 years.

To investigate the clinical and radiographic outcomes of a chemically modified sandblasted large-grit acid-etched implant (hydrophilic) in lateral sinus floor elevation (LSFE), compared with a conventional one (hydrophobic). A retrospective study design was adopted. Patients who received LSFE with simultaneous implant placement were recruited. According to different types of implant surfaces, patients were divided into two groups (the hydrophilic group and the hydrophobic group). Implant survival rate (SR), endo-sinus bone stability on the radiographs, mean probing depths, percentage of bleeding on probing, marginal bone loss, and patient satisfaction were evaluated. A total of 106 patients with 180 implants (hydrophilic:101, hydrophobic:79) in 119 maxillary sinuses were included. The follow-up period ranged from 2 to 5 years. Three hydrophobic implants and one hydrophilic implant in four different patients failed. The SR of the hydrophilic group was higher than that of the hydrophobic group but without a significant difference (p > .05). The change and change rate of endo-sinus bone height (ΔESBH and RΔESBH) and bone volume (ΔESBV and RΔESBV) in the hydrophilic group were less than those in the hydrophobic group, with a significant difference at 6 months after implantation. No other significant difference was found between the two groups. Within the limitations of this study, both hydrophilic and hydrophobic implants were suitable for LSFE with predictable clinical outcomes. Meanwhile, hydrophilic implants could contribute to the grafted endo-sinus bone stability during healing time.

Longitudinal associations between preschool children’s theory of mind, emotion understanding, and positive peer relationships

The positive links between children’s theory of mind (ToM), emotion understanding, and positive peer relationships are well established. However, the existing literature lacks comprehensive studies investigating the longitudinal interplay between these components in preschool-aged children. This study aimed to fill this gap by examining the concurrent and longitudinal associations between young children’s social cognition and their positive peer relationships at three different time points over the course of 7 months. A sample of 211 preschool children (age in months: MT1 = 43.2, SDT1 = 6.6) underwent standardized assessments evaluating their ToM and emotion understanding, while playgroup educators reported on children’s positive peer relationships. Using multivariate latent growth modeling, we expected to find that higher levels of ToM and emotion understanding would be associated with a greater rate of change in positive peer relationships and that higher levels of positive peer relationships would be associated with a higher rate of change in ToM and emotion understanding. Contrary to our expectations, the results did not support the anticipated longitudinal associations. Nevertheless, a noteworthy correlation emerged between children’s emotion understanding and positive peer relationships at T1, in line with previous research and social-constructivist theories.

Longitudinal changes of refractive error in preschool children with congenital ectopia lentis.

Congenital ectopia lentis (CEL) is a hereditary eye disease which severely impacts preschool children's visual function and development. This study aimed to evaluate the longitudinal changes in spherical equivalent (SE) refractive error in preschool children with CEL. A retrospective cohort study was conducted at Zhongshan Ophthalmic Center, Guangzhou, China. Medical records of CEL patients under 6-year-old who were diagnosed with Marfan syndrome at the initial visit from January 2014 to March 2022 were collected and were divided into surgery and non-surgery groups. Mean change rate of SE in the two groups was evaluated, and the potential associated factors of SE change rate were investigated by mixed-effect regression model. A total of 94 preschool patients from 14 provinces of China were included. Among the 42 children of the surgery group, the mean age with standard deviation (SD) was 5.02 ± 0.81years and patients experienced a myopic shift of -0.05 ± 0.09D/month in average. The mean age with SD of the 52 children of the non-surgery group was 4.34 ± 1.02years, and the mean myopic shift was -0.09 ± 0.14D/month. The mixed-effect regression model identified that higher degree of myopia at baseline was associated with slower myopic shift both in surgery (β = 0.901, 95% CI: 0.822 ~ 0.980, P < 0.001) and in non-surgery group (β = 1.006, 95% CI: 0.977 ~ 1.034, P < 0.001) in CEL patients. Surgical treatment (β = 2.635, 95% CI: 1.376 ~ 3.894, P < 0.001) was associated with slower myopic shift in all participants CEL patients. Myopic progression was slower in the surgery group than in the non-surgery group of CEL. Preschool CEL patients who met the surgical indication are suggested being performed with timely surgery to slow down the myopic progression.

A new promising indicator in prostate cancer screening: Prostate-specific antigen fluctuation rate

ObjectivesTo evaluate whether PSA fluctuation can be used to predict the risk of prostate cancer. Materials and methodsThe study included 1244 patients who underwent prostate biopsy at Kartal Dr. Lutfi Kirdar City Hospital between 2013 and 2021 (848 in non-cancer; 396 in cancer). The patient's age, last two PSA values (PSA1 and PSA2) within three months before the biopsy, the duration between two PSAs (days), prostate size (g) and PSA density (PSAD) were all recorded. PSA fluctuation rate (PSAfr) was defined as the change rate between two PSA values. ResultsPSAfr was significantly higher in the non-cancer group than in the prostate cancer group (15.2% (20.5) and 9.6% (14.4), P=.019). A Simple linear regression was used to examine the relationship between PSAfr and other factors such as age, PSA, PSAD, and prostate volume, but it was shown that these had no effect on PSA fluctuations. ROC analysis revealed a relatively low Area Under the Curve (AUC) for PSAfr (AUC, 0.584 (0.515–0.653)). However, the cut-off value of 12.35% was found to be significant, with a sensitivity of 58% and a specificity of 59% (P:.019, 95%CI). The odds ratio, adjusted for age, PSAD, and PSA2, was calculated as 0.545 (0.33−0.89) using logistic regression analysis to show the relationship between prostate cancer and PSAfr. As a result, those with high PSAfr were found to be 1.83 times less likely to be diagnosed with prostate cancer than those with low fluctuations. ConclusionPSAfr could be used in nomograms to predict prostate cancer risk and reduce the number of unnecessary biopsies.

Differences of Pine Wood Nematode (Bursaphelenchus xylophilus) Developmental Stages under High-Osmotic-Pressure Stress.

Under ion imbalance, water deficiency, and salt stress, the osmotic pressure of the tree sap increases, and pine wood nematodes (Bursaphelenchus xylophilus, PWN) parasitizing in the trees may be subjected to high-osmotic-pressure stress. KCl, L-malic acid, sucrose, and glycerol solutions were used as osmolytes to explore the highest osmotic concentration that PWN can tolerate. Survival analysis showed that when the treatment concentration exceeded 90%, only a few nematodes in the glycerol group survived under 6 h treatment, and most of the survivors were third-stage dispersal juveniles (DJ3). Further examination revealed that under different concentrations of glycerol-induced high osmotic pressure, the survival rate and body length change rate were the highest in the DJ3 and the lowest in the second-stage propagative juveniles. In order to explore the molecular mechanism of resistance of DJ3 to high osmotic stress, transcriptome sequencing was performed at each developmental stage of PWN and differentially expressed genes that were up-regulated or down-regulated only in DJ3 were screened. The expression of genes related to CoA in DJ3, a key enzyme in metabolism, was significantly higher than the other developmental stages. In addition, the expression of the anti-reversal signal pathway-related gene AKT-1 in DJ3 was significantly lower than in the other development stages. Therefore, the specific expression of genes in DJ3 under high osmotic pressure may help them rapidly produce and accumulate energy-related compounds and activate the adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) pathway to respond to damage caused by high-osmotic-pressure stress in time, thus promoting survival.

Partial volume correction in longitudinal tau PET studies: is it really needed?

Background[18F]flortaucipir (FTP) tau PET quantification is known to be affected by non-specific binding in off-target regions. Although partial volume correction (PVC) techniques partially account for this effect, their inclusion may also introduce noise and variability into the quantification process. While the impact of these effects has been studied in cross-sectional designs, the benefits and drawbacks of PVC on longitudinal FTP studies is still under scrutiny. The aim of this work was to study the performance of the most common PVC techniques for longitudinal FTP imaging. MethodsA cohort of 247 individuals from the Alzheimer's Disease Neuroimaging Initiative with concurrent baseline FTP-PET, amyloid-beta (Aβ) PET and structural MRI, as well as with follow-up FTP-PET and MRI were included in the study. FTP-PET scans were corrected for partial volume effects using Meltzer's, a simple and popular analytical PVC, and both the region-based voxel-wise (RBV) and the iterative Yang (iY) corrections. FTP SUVR values and their longitudinal rates of change were calculated for regions of interest (ROI) corresponding to Braak Areas I-VI, for a temporal meta-ROI and for regions typically displaying off-target FTP binding (caudate, putamen, pallidum, thalamus, choroid plexus, hemispheric white matter, cerebellar white matter, and cerebrospinal fluid). The longitudinal correlation between binding in off-target and target ROIs was analysed for the different PVCs. Additionally, group differences in longitudinal FTP SUVR rates of change between Aβ-negative (A-) and Aβ-positive (A+), and between cognitively unimpaired (CU) and cognitively impaired (CI) individuals, were studied. Finally, we compared the ability of different partial-volume-corrected baseline FTP SUVRs to predict longitudinal brain atrophy and cognitive decline. ResultsAmong off-target ROIs, hemispheric white matter showed the highest correlation with longitudinal FTP SUVR rates from cortical target ROIs (R2=0.28–0.82), with CSF coming in second (R2=0.28–0.42). Application of voxel-wise PVC techniques minimized this correlation, with RBV performing best (R2=0.00–0.07 for hemispheric white matter). PVC also increased group differences between CU and CI individuals in FTP SUVR rates of change across all target regions, with RBV again performing best (No PVC: Cohen's d = 0.26–0.66; RBV: Cohen's d = 0.43–0.74). These improvements were not observed for differentiating A- from A+ groups. Additionally, voxel-wise PVC techniques strengthened the correlation between baseline FTP SUVR and longitudinal grey matter atrophy and cognitive decline. ConclusionQuantification of longitudinal FTP SUVR rates of change is affected by signal from off-target regions, especially the hemispheric white matter and the CSF. Voxel-wise PVC techniques significantly reduce this effect. PVC provided a significant but modest benefit for tasks involving the measurement of group-level longitudinal differences. These findings are particularly relevant for the estimations of sample sizes and analysis methodologies of longitudinal group studies.

Glaciers determine the sensitivity of hydrological processes to perturbed climate in a large mountainous basin on the Tibetan Plateau

Abstract. The major rivers on the Tibetan Plateau supply important freshwater resources to riparian regions but have been undergoing significant climate change in recent decades. Understanding the sensitivities of hydrological processes to climate change is important for water resource management, but large divergences exist in previous studies because of the uncertainties of hydrological models and climate projection data. Meanwhile, the spatial pattern of local hydrological sensitivities was poorly explored despite the strong heterogeneity on the Tibetan Plateau. This study adopted the climate perturbation method to analyze the hydrological sensitivities of a typical large mountainous basin (Yarlung Tsangpo River, YTR) to climate change. We utilized the tracer-aided hydrological model Tsinghua Representative Elementary Watershed-Tracer-aided version (THREW-T) to simulate the hydrological and cryospheric processes in the YTR basin. Multiple datasets and internal stations were used to validate the model to provide confidence in the baseline simulation and the sensitivity analysis. Results indicated that (1) the THREW-T model performed well in simulating the streamflow, snow cover area (SCA), glacier mass balance (GMB) and stream water isotope, ensuring good representation of the key cryospheric processes and a reasonable estimation of the runoff components. The model performed acceptably in simulating the streamflow at eight internal stations located in the mainstream and two major tributaries, indicating that the spatial pattern of hydrological processes was reflected by the model. (2) Increasing temperature led to decreasing annual runoff, smaller inter-annual variation, more even intra-annual distribution and an earlier maximum runoff. It also influenced the runoff regime by increasing the contributions of rainfall and glacier melt overland runoff but decreasing the subsurface runoff and snowmelt overland runoff. Increasing precipitation had the opposite effect to increasing temperature. (3) The local runoff change in response to increasing temperature varied significantly, with a changing rate of −18.6 % to 54.3 % for 5∘ of warming. The glacier area ratio (GAR) was the dominant factor in the spatial pattern of hydrological sensitivities to both perturbed temperature and precipitation. Some regions had a non-monotonic runoff change rate in response to climate perturbation, which represented the most dynamic regions within the basin, as they kept shifting between energy- and water-limited stages. The GAR and mean annual precipitation (MAP) of the non-monotonic regions had a linear relation and formed the boundary of regions with different runoff trends in the GAR–MAP plot.

Cambios estacionales en la biomasa de Eichhornia crassipes (Mart.) Somls y su fauna en una laguna del Chaco (Argentina)

Biomass determinations were made in natural stands of Eichhornia crassipes throughout two year. The samples were monthly collected with a 62 cm diameter ring. The values indicated in the text are the averages of five replicates taken in a transection from a littoral to a central position.The annual net production was obtained from the difference between the final and initial biomass.Four functional compartments were considering: total standing crop; green leaves, roots and rhizomes biomass; dead attached leaves and litter. The greatest total standing crop found in mid summer, was 25 Tn/ha. In the same period, the máximum biomass was recorded. The roots and rhizomes have representad between 31 and 55% of the biomass.The máximum rate of biomass change was found in setember (6,30 Tn/ha).Losses by death (attached leaves and litter) were small before the seasonal máximum plant biomass. The litter ocurring in spring time, has been produced during the last winter.The fauna biomass in the Barranqueras pond was much lower than in other subtropical lakes (8 g/m3 in winter and 16 g/m3 in summer).The high losses from a E. crassipes community are related with the fast activity of the fitofagous during the summer.