Search

In this study, the resolvent operator of the impulsive dynamic singular Sturm–Liouville problem is considered. The spectral function was first established. The integral representation of the resolvent operator is obtained using this function. [ABSTRACT FROM AUTHOR]

This retrospective cohort study used Taussig Cancer Center's Myeloma Patient Registry to identify adults with multiple myeloma diagnosed between January 2017-December 2021. Electronic health records data captured time from diagnosis to initial prescription fill for oral antimyeloma medications and initiation of facility administered or oral antimyeloma treatment. We identified 720 patients with a mean age at diagnosis of 67 years ±11; 55% were male, 77% White, 22% Black, 1% other races, covered by private insurance (36%), traditional Medicare (29%), Medicare Advantage (25%), and Medicaid (8.3%). Over a third of patients (37%) resided in an area in the most disadvantaged area deprivation index (ADI) quartile. The median available follow-up was 765 days. Seventy-five percent of the cohort filled an oral antimyeloma medication prescription (excluding corticosteroids), with a median time to fill of 28 days (IQR, 15–61). In the multivariable Cox regression model, Black race (vs. White, adjusted hazard ratio [aHR], 0.61, 95% CI, 0.42–0.87), older age at diagnosis (aHR per 1 year, 0.97, 95% CI, 0.95–0.98), diagnosis during an inpatient admission (aHR, 0.63, 95% CI, 0.43–0.92), and estimated glomerular filtration rate ≤29 ml/min/1.73 m2 (vs. ≥60, aHR, 0.46, 95% CI, 0.29–0.73) were negatively associated with prescription fill for oral antimyeloma medication at 30 days, while insurance type and ADI were not significant predictors. [ABSTRACT FROM AUTHOR]

In this study, a singular impulsive Hahn–Dirac system is studied. A spectral function has been established for this type of system. With the help of this function, the Parseval equation and eigenfunction expansion were obtained. [ABSTRACT FROM AUTHOR]

This study focuses on the archeological characterization of potsherds from Tigranakert in Artsakh belonging to different centuries (from 9–13 century) using SEM/EDS technique. Archeometry and archeological science correspond and refer to the application of scientific techniques to the analysis of archeological materials, as well as the processes involved in their manufacture (Williams, Late Roman Coarse Wares, Cooking Wares and Amphorae in the Mediterranean: Archaeology and Archaeometry, BAR International Series, London, 2005; Vigil de la Villa Mencía and García Giménez, La Ciencia y el Arte: Ciencias Experimentales y Conservación del Patrimonio Histórico. Instituto del Patrimonio Histórico Español, Madrid, 2008; Martinón-Torres and Killick, The Oxford Handbook of Archaeological Theory, Oxford University Press, Oxford, 2015). This paper presents a study of a set of ceramic samples using stratigraphic analysis coupled with SEM/EDX technique. Ceramic materials provide information on the clay materials employed in their manufacture (Hradil et al., Appl Clay Sci 165:135–147, 2018; Giannossa et al., J Cult Herit 43:242–248, 2020), hence facilitating the assignment of their autochthonous or allochthonous character (Kordatzaki et al., J Archaeol Sci Rep 7:526–529, 2016; Montana, Anthropol Sci12:175, 2020; Hein and Kilikoglou, Anthropol Sci 12:180, 2020). Analysis of the cross-section provides the stratigraphic evaluation of the ceramic body (holes, cavities, imperfections, granulometry, inclusions, and color), the glaze, or other superficial layers (glazes, transparency or opacity, color and saturation, defects, and other). SEM images showed that the potsherds have a quite poor vitrification degree and heterogeneous grain distribution, suggesting a simple firing technique. [ABSTRACT FROM AUTHOR]

This study investigates the effects of X-radiation on ATPase activity and antioxidant enzyme activity, particularly enzymes involved in proline biosynthesis, in yeast C. guilliermondii NP-4. Moreover, the study examined the post-irradiation repair processes in these cells. Results showed that X-irradiation at a dose of 300 Gy led to an increase in catalase (CAT) and superoxide dismutase (SOD) activity, as well as, an increase in the CAT/SOD ratio in C. guilliermondii NP-4. The repair of radiation-induced damage requires a substantial amount of energy, resulting in an increased demand for ATP in the irradiated and repaired yeasts. Consequently, the total and FoF1-ATPase activity in yeast homogenates and mitochondria increased after X-irradiation and post-irradiation repair. It was showed an increase in the activity of proline biosynthesis enzymes (ornithine transaminase and proline-5-carboxylate reductase) in X-irradiated C. guilliermondii NP-4, which remained elevated even after post-irradiation repair. As a result, the proline levels in X-irradiated and repaired yeasts were higher than those in non-irradiated cells. These findings suggest that proline may have a radioprotective effect on X-irradiated C. guilliermondii NP-4 yeasts. Taken together this study provides insights into the effects of X-radiation on ATPase activity, antioxidant enzyme activity, and proline biosynthesis in C. guilliermondii NP-4 yeast cells, highlighting the potential radioprotective properties of proline in X-irradiated yeasts. [ABSTRACT FROM AUTHOR]

Multifunctional elements are a special class of elements, the reliability model of which differs from the classical two-pole "on-off" model. A multifunctional element can have partly false states in addition to nonfalse and false states. The multifunctionality of the elements leads to the formation of flexible, adaptable systems with reconfigurable structure, in which, in case of partial failure of the element, it is possible to continue the successful functioning of the system by redistributing the functions between the elements. In this paper, the properties of multifunctional elements (MFE) and systems, assembled on their basis, methods of structural analysis, logical-probabilistic reliability models and issues of optimal reconfiguration of systems based on MFE are discussed. [ABSTRACT FROM AUTHOR]

Nutrient runoff from agricultural regions of the midwestern U.S. corn belt has degraded water quality in many inland and coastal water bodies such as the Great Lakes and Gulf of Mexico. Under current climate, observational studies have shown that winter cover crops can reduce dissolved nitrogen and phosphorus losses from row-cropped agricultural watersheds, but performance of cover crops in response to climate variability and climate change has not been systematically evaluated. Using the Soil & Water Assessment Tool (SWAT) model, calibrated using multiple years of field-based data, we simulated historical and projected future nutrient loss from two representative agricultural watersheds in northern Indiana, USA. For 100% cover crop coverage, historical simulations showed a 31–33% reduction in nitrate (NO3−) loss and a 15–23% reduction in Soluble Reactive Phosphorus (SRP) loss in comparison with a no-cover-crop baseline. Under climate change scenarios, without cover crops, projected warmer and wetter conditions strongly increased nutrient loss, especially in the fallow period from Oct to Apr when changes in infiltration and runoff are largest. In the absence of cover crops, annual nutrient losses for the RCP8.5 2080s scenario were 26–38% higher for NO3−, and 9–46% higher for SRP. However, the effectiveness of cover crops also increased under climate change. For an ensemble of 60 climate change scenarios based on CMIP5 RCP4.5 and RCP8.5 scenarios, 19 out of 24 ensemble-mean simulations of future nutrient loss with 100% cover crops were less than or equal to historical simulations with 100% cover crops, despite systematic increases in nutrient loss due to climate alone. These results demonstrate that planting winter cover crops over row-cropped land areas constitutes a robust climate change adaptation strategy for reducing nutrient losses from agricultural lands, enhancing resilience to a projected warmer and wetter winter climate in the midwestern U.S. [ABSTRACT FROM AUTHOR]

Nuclear cytoplasmic transport is mediated by many receptors that recognize specific nuclear localization signals on proteins and RNA and transport these substrates through nuclear pore complexes. Facilitated diffusion through nuclear pore complexes requires the attachment of transport receptors. Despite the relatively large tunnel diameter, some even small proteins (less than 20–30 kDa), such as histones, pass through the nuclear pore complex only with transport receptors. Over several decades, considerable material has been accumulated on the structure, architecture, and amino acid composition of the proteins included in this complex and the sequence of many receptors. We consider the data available in the literature on the structure of the nuclear pore complex and possible mechanisms of nuclear-cytoplasmic transport, applying the theory of electrostatic interactions in the context of our data on changes in the electrokinetic potential of nuclei and our previously proposed physical model of the mechanism of facilitated diffusion through the nuclear pore complex (NPC). According to our data, the main contribution to the charge of the nuclear membrane is made by anionic phospholipids, which are part of both the nuclear membrane and the nuclear matrix, which creates a potential difference between them. The nuclear membrane is a four-layer phospholipid dielectric, so the potential vector can only pass through the NPC, creating an electrostatic funnel that "pulls in" the positively charged load-NLS-NTR trigger complexes. Considering the newly obtained data, an improved model of the previously proposed physical model of the mechanism of nuclear-cytoplasmic transport is proposed. This model considers the contribution of electrostatic fields to the transportation speed when changing the membrane's thickness in the NPC basket at a higher load. [ABSTRACT FROM AUTHOR]

Globally, COVID-19 has been shown to have had a wide ranging and significant impact on individuals' daily living, and physical and mental health. However, there are some groups of individuals who may encounter unique challenges with regards to COVID-19 and whose experiences have not been investigated thus far. Therefore, this study aimed to understand the experiences of adults with a facial visible difference in relation to COVID-19 and lockdown. Semi-structured interviews were conducted with 21 adults with a variety of facial visible differences (e.g., cleft lip/palate, facial scars, skin conditions) and analyzed using inductive reflexive thematic analysis. This analysis generated three themes (Escaping the external gaze; Existing feelings manifesting in new challenges; COVID-19 taking priority). The results of this study suggest that the first U.K. lockdown from the COVID-19 pandemic created significant challenges for some individuals with a facial visible difference, and ongoing restrictions and social distancing measures might be particularly challenging for those who experience anxiety around social encounters. These findings highlight the importance of providing appropriate and accessible support for people with facial differences during lockdown and as restrictions ease. [ABSTRACT FROM AUTHOR]

Multiscale modeling of marine and aerial plankton has traditionally been difficult to address holistically due to the challenge of resolving individual locomotion dynamics while being carried with larger-scale flows. However, such problems are of paramount importance, e.g., dispersal of marine larval plankton is critical for the health of coral reefs, and aerial plankton (tiny arthropods) can be used as effective agricultural biocontrol agents. Here we introduce the open-source, agent-based modeling software Planktos targeted at 2D and 3D fluid environments in Python. Agents in this modeling framework are relatively tiny organisms in sufficiently low densities that their effect on the surrounding fluid motion can be considered negligible. This library can be used for scientific exploration and quantification of collective and emergent behavior, including interaction with immersed structures. In this paper, we detail the implementation and functionality of the library along with some illustrative examples. Functionality includes arbitrary agent behavior obeying either ordinary differential equations, stochastic differential equations, or coded movement algorithms, all under the influence of time-dependent fluid velocity fields generated by computational fluid dynamics, experiments, or analytical models in domains with static immersed mesh structures with sliding or sticky collisions. In addition, data visualization tools provide images or animations with kernel density estimation and velocity field analysis with respect to deterministic agent behavior via the finite-time Lyapunov exponent. [ABSTRACT FROM AUTHOR]

Agriculture in Africa is rapidly expanding but with this comes potential disbenefits for the environment and human health. Here, we retrospectively assess whether childhood malaria in sub-Saharan Africa varies across differing agricultural land uses after controlling for socio-economic and environmental confounders. Using a multi-model inference hierarchical modelling framework, we found that rainfed cropland was associated with increased malaria in rural (OR 1.10, CI 1.03–1.18) but not urban areas, while irrigated or post flooding cropland was associated with malaria in urban (OR 1.09, CI 1.00–1.18) but not rural areas. In contrast, although malaria was associated with complete forest cover (OR 1.35, CI 1.24–1.47), the presence of natural vegetation in agricultural lands potentially reduces the odds of malaria depending on rural–urban context. In contrast, no associations with malaria were observed for natural vegetation interspersed with cropland (veg-dominant mosaic). Agricultural expansion through rainfed or irrigated cropland may increase childhood malaria in rural or urban contexts in sub-Saharan Africa but retaining some natural vegetation within croplands could help mitigate this risk and provide environmental co-benefits. [ABSTRACT FROM AUTHOR]

The anti-angiogenic effects of bisphosphonates have been hypothesized as one of the major etiologic factors in the development of medication-related osteonecrosis of the jaw (MRONJ), a severe debilitating condition with limited treatment options. This study evaluated the potential of a gelatine-hyaluronic acid hydrogel loaded with the angiogenic growth factor, vascular endothelial growth factor (VEGF), as a local delivery system to aid in maintaining vascularization in a bisphosphonate-treated (Zoledronic Acid) rodent maxillary extraction defect. Healing was assessed four weeks after implantation of the VEGF-hydrogel into extraction sockets. Gross examination and histological assessment showed that total osteonecrosis and inflammatory infiltrate was significantly reduced in the presence of VEGF. Also, total vascularity and specifically neovascularization, was significantly improved in animals that received VEGF hydrogel. Gene expression of vascular, inflammatory and bone specific markers within the defect area were also significantly altered in the presence of VEGF. Furthermore, plasma cytokine levels were assessed to determine the systemic effect of locally delivered VEGF and showed similar outcomes. In conclusion, the use of locally delivered VEGF within healing extraction sockets assists bone healing and prevents MRONJ via a pro-angiogenic and immunomodulatory mechanism. [ABSTRACT FROM AUTHOR]

Copyright of Herzschrittmachertherapie und Elektrophysiologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Herzschrittmachertherapie und Elektrophysiologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Yellow fever virus (YFV) is a zoonotic arbovirus affecting both humans and non-human primates (NHP's) in Africa and South America. Previous descriptions of YF's seasonality have relied purely on climatic explanations, despite the high proportion of cases occurring in people involved in agriculture. We use a series of random forest classification models to predict the monthly occurrence of YF in humans and NHP's across Brazil, by fitting four classes of covariates related to the seasonality of climate and agriculture (planting and harvesting), crop output and host demography. We find that models captured seasonal YF reporting in humans and NHPs when they considered seasonality of agriculture rather than climate, particularly for monthly aggregated reports. These findings illustrate the seasonality of exposure, through agriculture, as a component of zoonotic spillover. Additionally, by highlighting crop types and anthropogenic seasonality, these results could directly identify areas at highest risk of zoonotic spillover. Yellow fever virus (YFV) is an arbovirus affecting humans and non-human primates (NHPs) with seasonal transmission. Here Hamlet et al. model the monthly occurrence of YF in humans and NHPs across Brazil and show that seasonality of agriculture is an important predictor of seasonal YF transmission. [ABSTRACT FROM AUTHOR]

Within-person studies of emotional disclosure have found evidence of a disclosure-discordance effect of depression, whereby the positive association between the intensity of one's emotional experience and verbal disclosure of that experience weakens with increasing depression symptoms. Because these previous studies have exclusively been naturalistic ones, we examined the disclosure-discordance effect of depression in the lab. Participants (N = 115) completed a measure of depression symptoms and viewed a series of emotionally evocative photographs. Emotion-expressive behavior while viewing each photograph was rated by judges, subjective emotional experience was assessed via self-report, and emotional disclosure just after the photograph was viewed was rated by different judges. Multilevel analyses indicated that depression symptoms moderated the association between the behavioral (i.e., facial) expression of emotion intensity and disclosure of emotion. Moderation was not supported in analyses with self-reported emotional intensity as a predictor. These findings partly supported the disclosure-discordance effect, and they inform methods of empirically examining the effect of depression symptoms on the verbal disclosure of emotion. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic has resulted in substantial mortality worldwide. However, to date, countries in the Middle East and Africa have reported considerably lower mortality rates than in Europe and the Americas. Motivated by reports of an overwhelmed health system, we estimate the likely under-ascertainment of COVID-19 mortality in Damascus, Syria. Using all-cause mortality data, we fit a mathematical model of COVID-19 transmission to reported mortality, estimating that 1.25% of COVID-19 deaths (sensitivity range 1.00% – 3.00%) have been reported as of 2 September 2020. By 2 September, we estimate that 4,380 (95% CI: 3,250 – 5,550) COVID-19 deaths in Damascus may have been missed, with 39.0% (95% CI: 32.5% – 45.0%) of the population in Damascus estimated to have been infected. Accounting for under-ascertainment corroborates reports of exceeded hospital bed capacity and is validated by community-uploaded obituary notifications, which confirm extensive unreported mortality in Damascus. Reported COVID-19 mortality rates have been relatively low in Syria, but there has been concern about overwhelmed health systems. Here, the authors use community mortality indicators and estimate that <3% of COVID-19 deaths in Damascus were reported as of 2 September 2020. [ABSTRACT FROM AUTHOR]

Using an ensemble of 10 statistically downscaled global climate model (GCM) simulations, we project future climate change impacts on the state of Indiana (IN) for two scenarios of greenhouse gas concentrations (a medium scenario—RCP4.5 and a high scenario—RCP 8.5) for three future time periods (2020s, 2050s, 2080s). Relative to a 1971–2000 baseline, the projections show substantial changes in temperature (T) for IN, with a change in the annual ensemble mean T for the 2080s RCP8.5 scenario of about 5.6 °C (10.1 °F). Such changes also indicate major changes in T extremes. For southern IN, the number of days with daily maximum T above 35 °C (95 °F) is projected to be about 100 days per year for the 2080s RCP8.5 scenario, as opposed to an average of 5 days for the historical baseline climate. Locations in northern IN could experience 50 days per year above 35 °C (95 °F) for the same conditions. Energy demand for cooling, as measured by cooling degree days (CDD), is projected to increase nearly fourfold in response to this extreme warming, but heating demand as measured by heating degree days (HDD) is projected to decline by 30%, which would result in a net reduction in annual heating/cooling energy demand for consumers. The length of the growing season is projected to increase by about 30 to 50 days by the 2080s for the RCP8.5 scenario, and USDA hardiness zones are projected to shift by about one full zone throughout IN. By the 2080s, all GCM simulations for the RCP8.5 scenario show higher annual precipitation (P) over the Midwest and IN. Projected seasonal changes in P include a 25–30% increase in winter and spring by the 2080s for the RCP8.5 scenarios and a 1–7% decline in summer and fall P (although there is a low model agreement in the latter two seasons). Rising T is projected to cause systematic decreases in the snow-to-rain ratio from Nov-Mar. Snow is projected to become uncommon in southern IN by the 2080s for the RCP8.5 scenario, and snowfall is substantially reduced in other areas of the state. The combined effects of these changes in T, P, and snowfall will likely result in increased surface runoff and flooding during winter and spring. [ABSTRACT FROM AUTHOR]

We aimed to evaluate the impact of non-surgical periodontal treatment on the salivary expression of leptin, TNF-α, sclerostin, parathyroid hormone, osteoprotegerin, osteopontin, osteocalcin, IL-6, IL-1β and fibroblast growth factor 23 in patients with chronic periodontitis after 1 year of follow-up. Fifteen patients with chronic periodontitis (56.0 ± SD 9.6 years) and 15 subjects with gingivitis (39.7 ± SD 4.4 years) were included in the study. Clinical periodontal parameters, such as probing pocket depth (PPD), clinical attachment level (CAL), % of plaque and bleeding on probing (BOP) were evaluated, and non-stimulated whole saliva was collected from all patients before periodontal treatment and after 1 year of follow-up. A bead-based multiplex assay measured cytokines. In the chronic periodontitis group, periodontal treatment significantly improved clinical parameters and reduced the salivary levels of IL-1β, leptin and TNF-α (p = 0.002, 0.007 and 0.015, respectively). In the gingivitis group, there were also significant improvements in the mean patient %BOP, % Plaque, CAL and PPD. However, there were no significant changes in the cytokine's salivary levels. In conclusion, chronic periodontitis patients showed a significant reduction in the salivary levels of leptin, TNF-α and IL-1β 1 year after periodontal treatment and a significant improvement in their clinical periodontal parameters suggesting that periodontal treatment alone can downregulate important cytokines associated with bone metabolism. [ABSTRACT FROM AUTHOR]

An amendment to this paper has been published and can be accessed via a link at the top of the paper. [ABSTRACT FROM AUTHOR]

More than one billion people globally, including one in five women and one in seven men, are projected to be living with obesity (body mass index [BMI] >= 30 kg/m SP 2 sp ) by 2030 [[1]]. The 2022 American Society for Metabolic and Bariatric Surgery (ASMBS) and the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) published a joint statement on the currently available scientific information on bariatric surgery and its indications [[5]]. [Extracted from the article]

The literature on emotion reactivity among people with major depressive disorder (MDD) indicates that people with MDD show diminished reactivity to negative events as compared to non-depressed controls. This diminished reactivity may only be at the highest levels of depression symptoms, suggesting a nonlinear association between depression symptoms and emotion reactivity. Unfortunately, depression has not been examined as a continuum in this line of research; moreover, the time course of reactivity during an emotional event has not been adequately examined. Participants (N = 100) completed a measure of depression symptoms and then viewed a sadness-inducing 11-min film clip while their facial expressions were video recorded and coded separately for each minute of the film clip. Growth-curve analyses indicated a quadratic effect of depression symptoms on curves for facial expressions of sadness and happiness, such that the change in growth/decay first increased and then decreased from low to high levels of depression symptoms. This result supports the idea that the negative mood inherent in depression potentiates reactivity at lower ends of the depression continuum but that reactivity is dampened at higher levels of depression. This suggests that researchers specify the specific range of depression symptoms under investigation (e.g., mild, moderate, dysphoric, severely depressed) when studying the role of depression on emotional reactivity. [ABSTRACT FROM AUTHOR]

Plant biomass offers a renewable and environmentally favorable source of sugars that can be converted to different chemicals, second-generation ethanol, and other liquid fuels. Cellulose makes up approximately 45 % of the dry weight of lignocellulosic biomass. Prior to the enzymatic hydrolysis of cellulose, lignin and hemicellulose must be structurally altered or removed, at least in part, by chemical and/or physical pretreatments. However, the high cost and low efficiency of the enzymatic hydrolysis prevent the process from being economically competitive. For this reason, it is necessary to find enzymes suitable for this type of process, with higher specific activities and greater efficiency. Members of the Bacillus and Paenibacillus genera have been traditionally used for the production of many enzymes for industrial applications. Cellulases produced by both genera have shown activity on soluble and crystalline cellulose and high thermostability and/or activity over a wide pH spectrum. In this review, the most recent information about the characterization of cellulolytic enzymes obtained from new strains of the Bacillus and Paenibacillus genera are reviewed. We focused on the variety of isoenzymes produced by these cellulolytic strains, their optimal production and reaction conditions, and their kinetic parameters and biotechnological potential. [ABSTRACT FROM AUTHOR]

We present several software and hardware implementations of QUAD, a recently introduced stream cipher designed to be provably secure and practical to implement. The software implementations target both a personal computer and an ARM microprocessor. The hardware implementations target field-programmable gate arrays. The purpose of our work was to first find the baseline performance of QUAD implementations, then to optimize our implementations for throughput. Our software implementations perform comparably to prior work. Our hardware implementations are the first known implementations to use random coefficients, in agreement with QUAD's security argument, and achieve much higher throughput than prior implementations. [ABSTRACT FROM AUTHOR]

Direct measurements of net N production, oxygen, and inorganic nutrient fluxes at the sediment-water interface were conducted in the San José Lagoon (SJL), a tropical coastal lagoon located at the San Juan Bay Estuary, Puerto Rico, that is heavily impacted by anthropogenic activities. Sediment of the SJL had high organic matter (average = 16.7 %; SD = 9.0), pore water ammonium (541 μM ± 422), and pore water soluble reactive phosphorus (SRP) (57 μM ± 48) concentrations. High fluxes of oxygen (−1999 μmol m h ± 2180) and N-N (192 μmol m h ± 315) fluxes were observed. Similarly, high fluxes of ammonium (770 μmol m h ± 701) and SRP fluxes (167 μmol m h ± 138) were measured, with moderate nitrate fluxes (−40 μmol m h ± 53) mostly directed into the sediment. The dissolved inorganic nitrogen and soluble reactive phosphorus ratio (DIN/SRP) was low relative to the Redfield ratio and suggested that the sediment would support SJL as a nitrogen-limited system. An experiment with higher nitrate concentration resulted in a significant response ( p < 0.05) of denitrifying microbes and ammonium fluxes to a 100-μM KNO addition. Net N production was an important sink in the nitrogen balance of the SJL, though most remineralized N was released as ammonium. Efforts to mitigate eutrophication in the SJL require consideration of the substantial role that sediments play in biogeochemical cycles. [ABSTRACT FROM AUTHOR]