Environmental drivers of increased ecosystem respiration in a warming tundra.

Arctic and alpine tundra ecosystems are large reservoirs of organic carbon1,2. Climate warming may stimulate ecosystem respiration and release carbon into the atmosphere3,4. The magnitude and persistency of this stimulation and the environmental mechanisms that drive its variation remain uncertain5-7. This hampers the accuracy of global land carbon-climate feedback projections7,8. Here we synthesize 136 datasets from 56 open-top chamber in situ warming experiments located at 28 arctic and alpine tundra sites which have been running for less than 1 year up to 25 years. We show that a mean rise of 1.4 °C [confidence interval (CI) 0.9-2.0 °C] in air and 0.4 °C [CI 0.2-0.7 °C] in soil temperature results in an increase in growing season ecosystem respiration by 30% [CI 22-38%] (n = 136). Our findings indicate that the stimulation of ecosystem respiration was due to increases in both plant-related and microbial respiration (n = 9) and continued for at least 25 years (n = 136). The magnitude of the warming effects on respiration was driven by variation in warming-induced changes in local soil conditions, that is, changes in total nitrogen concentration and pH and by context-dependent spatial variation in these conditions, in particular total nitrogen concentration and the carbon:nitrogen ratio. Tundra sites with stronger nitrogen limitations and sites in which warming had stimulated plant and microbial nutrient turnover seemed particularly sensitive in their respiration response to warming. The results highlight the importance of local soil conditions and warming-induced changes therein for future climatic impacts on respiration.

A single-centre analysis of post-colonoscopy colorectal cancer.

PATIENTS AND METHODS: A prospective registration of patients with colorectal cancer and a colonoscopy within the last 10 years. We tried to classify these post-colonoscopy colorectal cancers (PCCRCs) by most reasonable explanation and into subcategories suggested by the World Endoscopy Organization (WEO) and calculated the unadjusted PCCRC rate. RESULTS: 47 PCCRCs were identified. The average age at diagnosis of PCCRC was 73 years. PCCRCs were more located in the right colon with a higher percentage of MSI-positive and B-RAF mutated tumours. The average period between index colonoscopy and diagnosis of PCCRC was 4.2 years. Sixty-eight % of all PCCRCs could be explained by procedural factors. The mean PCCRC-3y of our department was 2.46%. CONCLUSIONS: The data of our centre are in line with the data of the literature from which can be concluded that most postcolonoscopy colorectal cancers are preventable. The PCCRC-3y is an important quality measure for screening colonoscopy. Ideally all centres involved in the population screening should measure the PCCRC-3 y annually, with cooperation of the cancer registry and reimbursement data provided by the Intermutualistic Agency (IMA).

Stopping antibiotic therapy after 72 h in patients with febrile neutropenia following intensive chemotherapy for AML/MDS (safe study): A retrospective comparative cohort study.

BACKGROUND: Induction chemotherapy for acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) is almost universally complicated by febrile neutropenia(FN). Empirical broad-spectrum antibiotic therapy (EBAT) strategies advocated by guidelines result in long periods of broad-spectrum antibiotic therapy. We compared the outcome of AML/MDS patients treated with a 3-day versus a prolonged (until neutrophil recovery) regimen. METHODS: This is a retrospective comparative cohort study in AML or MDS patients undergoing remission-induction chemotherapy from 2011 to 2019, comparing 2 tertiary care hospitals with different strategies regarding antibiotic treatment for FN. At Erasmus University medical center(EMC), EBAT was stopped after 3 days of FN, in absence of a clinically or microbiologically documented infection. In the University Hospitals Leuven(UZL), a prolonged strategy was used, where EBAT was given until neutrophil recovery. The primary endpoint was a serious medical complication(SMC) defined as death or ICU admission in the 30 days after the start of chemotherapy. FINDINGS: 305 and 270 AML or MDS patients received chemotherapy at EMC and UZL, respectively. Broad-spectrum antibiotic treatment was given for a median of 19 days (IQR13-25) at UZL versus 9 days at EMC (IQR5-13) (p <0·001). With the 3-day EBAT strategy, an SMC was observed in 12·5% versus 8·9% with the prolonged strategy (p = 0·17). The hazard ratio for an SMC was not significantly higher with the 3-day strategy (HR 1·357,95%CI 0·765-2·409). INTERPRETATION: This study suggests that during remission induction chemotherapy it is safe to stop antibiotics after 3 days of FN in absence of infection. A comparison of both strategies in a prospective trial should be pursued.

Organoleptic quality of Ethiopian Arabica coffee deteriorates with increasing intensity of coffee forest management.

Arabica coffee (Coffea arabica L.) grows naturally as an understory shrub in the moist evergreen montane forests of Southwest Ethiopia. In response to an increasing local human population pressure and a growing coffee demand on the world market, coffee producing forests are increasingly managed to boost coffee yield. Here we compared organoleptic coffee quality between natural coffee producing forests, large coffee agroforests, and small coffee agroforests. Accounting for variability in Arabica coffee genotype and environment, we found that blind consensus scores, given by a panel of certified Q-Grade cuppers, were negatively affected by increasing forest management intensity. Importantly, only coffee from natural coffee producing forests qualified as specialty coffee following the Specialty Coffee Association of America's standards. We suggest that the most important drivers of deteriorating coffee quality include decreased shade levels and changing micro-climate and biotic interactions. Due to the low yields of coffee in natural coffee producing forests and the lack of quality price premiums, Ethiopian smallholder farmers are inclined to optimize for coffee quantity, rather than for quality, causing a significant challenge for the conservation of Ethiopian natural coffee producing forests.

Improved survival after LTx-associated acute GVHD with mAb therapy targeting IL2RAb and soluble TNFAb: Single-center experience and systematic review.

Acute graft-versus-host disease (GVHD) after liver transplant (LTx) is a rare complication with a high mortality rate. Recently, monoclonal antibody (mAb) treatment, specifically with anti-interleukin 2 receptor antibodies (IL2RAb) and anti-tumor necrosis factor-α antibodies (TNFAb), has gained increasing interest. However, evidence is mostly limited to case reports and the efficacy remains unclear. Here, we describe 5 patients with LTx-associated GVHD from our center and provide the results of our systematic literature review to evaluate the potential therapeutic benefit of IL2RAb/TNFAb treatment. Of the combined population of 155 patients (5 in our center and 150 through systematic search), 24 were given mAb (15.5%)-4 with TNFAb (2.6%) and 17 with IL2RAb (11%) ("mAb group")-and compared with patients who received other treatments (referred to as "no-mAb group"). Two-sided Fisher exact tests revealed a better survival when comparing treatment with mAb versus no-mAb (11/24 vs 27/131; P = .018), TNFAb versus no-mAb (3/4 vs 27/131; P = .034), and IL2RAb versus no-mAb (8/17 vs 27/131; P = .029). This systematic review suggests a beneficial effect of mAb treatment and a promising role for TNFAb and IL2RAb as a first-line strategy to treat LTx-associated acute GVHD.

Laparoscopic liver resection for hemorrhagic hepatocellular adenoma in a pregnant patient.

INTRODUCTION: Hepatocellular adenoma (HCA) is a benign neoplasm of the liver, however, with a potential for life-threatening hemorrhage. The unpredictable course during pregnancy poses a clinical dilemma in the pregnant patient. Intra-peritoneal rupture may lead to life-threatening situations with adverse outcome for mother and unborn child. A pre-emptive strategy with adequate treatment before pregnancy is strongly advised. However, the strategy for treating symptomatic HCA during pregnancy remains challenging as experience is limited. CASE PRESENTATION: A 31-year-old pregnant patient at the gestational age of 17 weeks presented with an acute episode of right upper abdomen pain. MR-imaging revealed a lesion of 9 cm located in segment III with stigmata of recent hemorrhage. At 18 weeks of gestation, she underwent a semi-elective laparoscopic left lateral sectionectomy. RESULTS: Surgery and postoperative recovery were uneventful. Patient was discharged at POD +6. At 40 weeks of gestation, she went in spontaneous labor and delivered a healthy baby. Histological examination confirmed a HCA, inflammatory subtype, showing features of hemorrhage. CONCLUSION: In the pregnant patient, HCA represents a significant diagnostic and therapeutic challenge. Anatomically favorable located lesions can be safely managed with laparoscopic liver resection. We suggest that laparoscopic liver resection should be considered as part of the currently available strategies for HCA during pregnancy.

Budd-Chiari syndrome: reassessment of a step-wise treatment strategy.

BACKGROUND AND STUDY AIMS: The Budd-Chiari syndrome is a rare disorder characterized by hepatic venous outflow obstruction. A step-wise management was recently proposed. The aim of this study is to reassess our treatment approach and long-term outcome. PATIENTS AND METHODS: The data of 37 Budd-Chiari patients, seen in our unit, were critically analyzed and compared with the ENVIE (European Network For Vascular Disorders of the Liver) data. RESULTS: Most patients had multiple prothrombotic conditions (41%), of which an underlying myeloproliferative neoplasm was the most frequent (59%). The JAK2V617F mutation was associated with more complete occlusion of all hepatic veins (JAK2 mutation +: 70% vs JAK2 mutation -: 23% and a higher severity score. The step-wise treatment algorithm used in our unit, in function of the severity of the liver impairment and the number and the extension of hepatic veins occluded, resulted in the following treatments: only anticoagulation (n = 7.21%), recanalization procedure (n = 4.21%), portosystemic shunts (n = 9.26%) and liver transplantation (n = 14.44%). This resulted in a 10 year survival rate of 90%. Treatment of the underlying hemostatic disorder offered a low recurrence rate. None of the 21 patients with a myeloproliferative neoplasm died in relation to the hematologic disorder. CONCLUSIONS: An individualized treatment regimen consisting of anticoagulation and interventional radiology and/or transplantation when necessary and strict follow-up of the underlying hematologic disorder, provided an excellent long-term survival, which confirm the data of the ENVIE study.

Spontaneous life-threatening hemobilia during acute liver failure successfully treated with transarterial embolization.

A 28-year-old patient admitted with jaundice, vomiting and deteriorating coagulopathy was diagnosed with acute liver failure. After listing for urgent transplantation, he developed Boerhaave's syndrome and massive hemobilia, two life-threatening complications. Massive hemobilia secondary to a fistula between the right hepatic artery and the right bile duct occurred several days after transjugular biopsy and was controlled with fluid resuscitation, transfusion and arterial embolization. Two days later he was transplanted successfully, and is currently doing well after more than 72 months. Aggressive treatment of potentially reversible complications during acute liver failure whilst awaiting transplantation is mandatory to allow survival of these patients.

Meta-analysis reveals profound responses of plant traits to glacial CO2 levels.

A general understanding of the links between atmospheric CO2 concentration and the functioning of the terrestrial biosphere requires not only an understanding of plant trait responses to the ongoing transition to higher CO2 but also the legacy effects of past low CO2. An interesting question is whether the transition from current to higher CO2 can be thought of as a continuation of the past trajectory of low to current CO2 levels. Determining this trajectory requires quantifying the effect sizes of plant response to low CO2. We performed a meta-analysis of low CO2 growth experiments on 34 studies with 54 species. We quantified how plant traits vary at reduced CO2 levels and whether C3 versus C4 and woody versus herbaceous plant species respond differently. At low CO2, plant functioning changed drastically: on average across all species, a 50% reduction in current atmospheric CO2 reduced net photosynthesis by 38%; increased stomatal conductance by 60% and decreased intrinsic water use efficiency by 48%. Total plant dry biomass decreased by 47%, while specific leaf area increased by 17%. Plant types responded similarly: the only significant differences being no increase in SLA for C4 species and a 16% smaller decrease in biomass for woody C3 species at glacial CO2. Quantitative comparison of low CO2 effect sizes to those from high CO2 studies showed that the magnitude of response of stomatal conductance, water use efficiency and SLA to increased CO2 can be thought of as continued shifts along the same line. However, net photosynthesis and dry weight responses to low CO2 were greater in magnitude than to high CO2. Understanding the causes for this discrepancy can lead to a general understanding of the links between atmospheric CO2 and plant responses with relevance for both the past and the future.

Gas purification by nonthermal plasma: a case study of ethylene.

The destruction of ethylene in a dielectric barrier discharge plasma is investigated by the combination of kinetic modeling and experiments, as a case study for plasma-based gas purification. The influence of the specific energy deposition on the removal efficiency and the selectivity toward CO and CO2 is studied for different concentrations of ethylene. The model allows the identification of the destruction pathway in dry and humid air. The latter is found to be mainly initiated by metastable N2 molecules, but the further destruction steps are dominated by O atoms and OH radicals. Upon increasing air humidity, the removal efficiency drops by ± 15% (from 85% to 70%), but the selectivity toward CO and CO2 stays more or less constant at 60% and 22%, respectively. Beside CO and CO2, we also identified acetylene, formaldehyde, and water as byproducts of the destruction process, with concentrations of 1606 ppm, 15033 ppm, and 185 ppm in humid air (with 20% RH), respectively. Finally, we investigated the byproducts generated by the humid air discharge itself, which are the greenhouse gases O3, N2O, and the toxic gas NO2.

Risk factors for bleeding and clinical implications in patients undergoing liver transplantation.

INTRODUCTION: Advanced liver disease is characterized by prolonged global coagulation tests such as prothrombin time (PT). Using Model of End-stage Liver Disease (MELD) score-based allocation, many current transplant recipients show advanced end-stage liver disease with an elevated international normalized ratio (INR). The relationship between abnormalities in coagulation tests and the risk of bleeding has been recently challenged among liver disease patients. In this study we reassessed risk factors for bleeding and the clinical implications for patients who underwent orthotopic liver transplantation (OLT). METHODS: We studied OLT patients between 2005 and 2011 excluding combined transplantations, retransplantations, or cases due to acute liver failure. We collected prospectively pre-OLT, during OLT, and post-OLT clinical and biochemical data to assess the risk for bleeding using linear regression models. RESULTS: The strongest predictor of overall survival among 286 patients with a mean follow-up of 32 months was the number of blood transfusions (P = .005). The risk factor for bleeding during surgery investigated by multivariate analysis only showed the INR (P < .001) and the presence of ascites (P = .003) to independently correlate with the amount of blood transfusion. Receiver operation characteristics (ROC) analysis performed to determine the risk for massive blood transfusion (more than 6 units) revealed a cut-off value for INR ≥ 1.6. Appreciation of the operative field by the surgeon during the intervention as "wet" versus "dry", amounts of blood transfusion and fresh frozen plasma, and stay in the intensive care unit (ICU) and in the hospital were all significantly different (P < .001) for patients with INR <1.6 versus INR ≥ 1.6. CONCLUSIONS: Bleeding during OLT affects the outcome. The risk is independently influenced by the presence of ascites (probably reflecting the degree portal hypertension) and an INR ≥ 1.6. To improve survival after OLT therapeutic interventions should be further explored to reduce the need for blood transfusions.

Septuagenarian and octogenarian donors provide excellent liver grafts for transplantation.

BACKGROUND: Wider utilization of liver grafts from donors ≥ 70 years old could substantially expand the organ pool, but their use remains limited by fear of poorer outcomes. We examined the results at our center of liver transplantation (OLT) using livers from donors ≥ 70 years old. METHODS: From February 2003 to August 2010, we performed 450 OLT including 58 (13%) using donors ≥ 70 whose outcomes were compared with those using donors <70 years old. RESULTS: Cerebrovascular causes of death predominated among donors ≥ 70 (85% vs 47% in donors <70; P < .001). In contrast, traumatic causes of death predominated among donors <70 (36% vs 14% in donors ≥ 70; P = .002). Unlike grafts from donors <70 years old, grafts from older individuals had no additional risk factors (steatosis, high sodium, or hemodynamic instability). Both groups were comparable for cold and warm ischemia times. No difference was noted in posttransplant peak transaminases, incidence of primary nonfunction, hepatic artery thrombosis, biliary strictures, or retransplantation rates between groups. The 1- and 5-year patient survivals were 88% and 82% in recipients of livers <70 versus 90% and 84% in those from ≥ 70 years old (P = .705). Recipients of older grafts, who were 6 years older than recipients of younger grafts (P < .001), tended to have a lower laboratory Model for End-Stage Liver Disease score (P = .074). CONCLUSIONS: Short and mid-term survival following OLT using donors ≥ 70 yo can be excellent provided that there is adequate donor and recipient selection. Septuagenarians and octogenarians with cerebrovascular ischemic and bleeding accidents represent a large pool of potential donors whose wider use could substantially reduce mortality on the OLT waiting list.

Outcomes of liver transplantations using donations after circulatory death: a single-center experience.

INTRODUCTION: Orthotopic liver transplantation (OLT) (LTx) using donation after circulatory death (DCD) donors is increasingly performed, but still considered to risk of poorer outcomes compared with standard donations after brain death (DBD)-OLT. Therefore we reviewed our results of DCD-OLT. PATIENTS AND METHODS: Between 2003 and 2010, we performed 30 DCD-OLT (6% of all OLT). We retrospectively reviewed medical records of donors and recipients after DCD versus DBD-OLT to analyze biliary complications, retransplantation rates, and patient/graft survivals. RESULTS: Median donor age was similar for DCD and DBD-OLT: 51 versus 53 years (P = .244). Median donor warm ischemia time (stop ventilation to cold perfusion in DCD donors) was 24 minutes. Median cold ischemia time was shorter for DCD (6 hours 54 minutes) compared with DBD-OLT (8 hours 36 minutes; P < .0001). Median laboratory model of end-stage liver disease score was 15 for DCD, and 16 for DBD-OLT (P = .59). Median post-OLT Aspartate Aminotransferase (AST) peak was higher after DCD: 1178 versus DBD-OLT 651 IU/L (P = .005). The incidence of nonanastomotic strictures was different: 33.3% for DCD versus 12.5% for DBD-OLT (P = .001). The overall retransplantation rate was 3% after both DCD and DBD-OLT. After DCD-LTx actuarial 1, 3- and 5-year patient survivals were 93, 85 and 85%, and corresponding graft survivals, 90%, 82%, and 82% respectively, and not different compared with DBD-OLT: 88%, 78%, and 72% (P = .348) and 85%, 74%, and 68% (P = .524) respectively. CONCLUSION: Despite substantial ischemic injury (high peak AST and biliary strictures) short- and long-term survival after DCD-OLT was comparable to DBD-OLT. Rapid donor surgery, careful donor and recipient selection, as well as short warm and cold ischemia times are key factors to optimize outcomes after DCD-OLT. However, strategies to reduce biliary complications remain warranted.

Liver transplantation in a patient with an intraabdominally located left ventricular assist device: surgical aspects--case report.

The presence of a cardiac assist device in a liver transplantation candidate should not be considered to be an absolute contraindication to transplantation. In this first case report of liver transplantation in a patient with an intraabdominally located left ventricular assist device, we have described the surgical aspects and discussed the timing of the liver transplantation and the removal of the left ventricular assist device.

Gastric outlet obstruction by a donor aortic tube after en bloc liver pancreas transplantation: a case report.

We present the case of a 30-year-old female suffering from a type five maturity onset diabetes of the young deficiency, resulting in type 1 diabetes and terminal renal insufficiency. She also had chronic and refractory pruritis due to primary sclerosing cholangitis-like fibrosis. She underwent combined en bloc liver and pancreas transplantation and kidney transplantation. The postoperative course was complicated by a gastric outlet obstruction due to compression of the native gastroduodenal junction by the donor aortic tube. This was treated by construction of a roux-en-Y gastrojejunostomy at posttransplant day 24. To our knowledge, compression of the gastroduodenal junction by a donor aortic tube after combined liver and pancreas (or multivisceral) transplantation has not been reported previously.

Litter stoichiometric traits of plant species of high-latitude ecosystems show high responsiveness to global change without causing strong variation in litter decomposition.

• High-latitude ecosystems are important carbon accumulators, mainly as a result of low decomposition rates of litter and soil organic matter. We investigated whether global change impacts on litter decomposition rates are constrained by litter stoichiometry. • Thereto, we investigated the interspecific natural variation in litter stoichiometric traits (LSTs) in high-latitude ecosystems, and compared it with climate change-induced LST variation measured in the Meeting of Litters (MOL) experiment. This experiment includes leaf litters originating from 33 circumpolar and high-altitude global change experiments. Two-year decomposition rates of litters from these experiments were measured earlier in two common litter beds in sub-Arctic Sweden. • Response ratios of LSTs in plants of high-latitude ecosystems in the global change treatments showed a three-fold variation, and this was in the same range as the natural variation among species. However, response ratios of decomposition were about an order of magnitude lower than those of litter carbon/nitrogen ratios. • This implies that litter stoichiometry does not constrain the response of plant litter decomposition to global change. We suggest that responsiveness is rather constrained by the less responsive traits of the Plant Economics Spectrum of litter decomposability, such as lignin and dry matter content and specific leaf area.

An unusual case of rectal perforation after liver transplantation.

We present the case of a 50-year-old patient in whom an anastomotic biliary stricture after liver transplantation was treated endoscopically by sphincterotomy, dilatation and stenting using a plastic biliary stent. A distal migration of the stent caused a perforation of the rectum which was treated following stent extraction per anum -- conservatively with antibiotics and temporary bowel rest.

Disturbance and resource availability act differently on the same suite of plant traits: revisiting assembly hypotheses.

Understanding the mechanisms of trait selection at the scale of plant communities is a crucial step toward predicting community assembly. Although it is commonly assumed that disturbance and resource availability constrain separate suites of traits, representing the regenerative and established phases, respectively, a quantification and test of this accepted hypothesis is still lacking due to limitations of traditional statistical techniques. In this paper we quantify, using structural equation modeling (SEM), the relative contributions of disturbance and resource availability to the selection of suites of traits at the community scale. Our model specifies and reflects previously obtained ecological insights, taking disturbance and nutrient availability as central drivers affecting leaf, allometric, seed, and phenology traits in 156 (semi-) natural plant communities throughout The Netherlands. The common hypothesis positing that disturbance and resource availability each affect a set of mutually independent traits was not consistent with the data. Instead, our final model shows that most traits are strongly affected by both drivers. In addition, trait-trait constraints are more important in community assembly than environmental drivers in half of the cases. Both aspects of trait selection are crucial for correctly predicting ecosystem processes and community assembly, and they provide new insights into hitherto underappreciated ecological interactions.

Seasonal climate manipulations have only minor effects on litter decomposition rates and N dynamics but strong effects on litter P dynamics of sub-arctic bog species.

Litter decomposition and nutrient mineralization in high-latitude peatlands are constrained by low temperatures. So far, little is known about the effects of seasonal components of climate change (higher spring and summer temperatures, more snow which leads to higher winter soil temperatures) on these processes. In a 4-year field experiment, we manipulated these seasonal components in a sub-arctic bog and studied the effects on the decomposition and N and P dynamics of leaf litter of Calamagrostis lapponica, Betula nana, and Rubus chamaemorus, incubated both in a common ambient environment and in the treatment plots. Mass loss in the controls increased in the order Calamagrostis < Betula < Rubus. After 4 years, overall mass loss in the climate-treatment plots was 10 % higher compared to the ambient incubation environment. Litter chemistry showed within each incubation environment only a few and species-specific responses. Compared to the interspecific differences, they resulted in only moderate climate treatment effects on mass loss and these differed among seasons and species. Neither N nor P mineralization in the litter were affected by the incubation environment. Remarkably, for all species, no net N mineralization had occurred in any of the treatments during 4 years. Species differed in P-release patterns, and summer warming strongly stimulated P release for all species. Thus, moderate changes in summer temperatures and/or winter snow addition have limited effects on litter decomposition rates and N dynamics, but summer warming does stimulate litter P release. As a result, N-limitation of plant growth in this sub-arctic bog may be sustained or even further promoted.

Glasshouse vs field experiments: do they yield ecologically similar results for assessing N impacts on peat mosses?

• Peat bogs have accumulated more atmospheric carbon (C) than any other terrestrial ecosystem today. Most of this C is associated with peat moss (Sphagnum) litter. Atmospheric nitrogen (N) deposition can decrease Sphagnum production, compromising the C sequestration capacity of peat bogs. The mechanisms underlying the reduced production are uncertain, necessitating multifactorial experiments. • We investigated whether glasshouse experiments are reliable proxies for field experiments for assessing interactions between N deposition and environment as controls on Sphagnum N concentration and production. We performed a meta-analysis over 115 glasshouse experiments and 107 field experiments. • We found that glasshouse and field experiments gave similar qualitative and quantitative estimates of changes in Sphagnum N concentration in response to N application. However, glasshouse-based estimates of changes in production--even qualitative assessments-- diverged from field experiments owing to a stronger N effect on production response in absence of vascular plants in the glasshouse, and a weaker N effect on production response in presence of vascular plants compared to field experiments. • Thus, although we need glasshouse experiments to study how interacting environmental factors affect the response of Sphagnum to increased N deposition, we need field experiments to properly quantify these effects.