Climate variability and extremes are expected to increase due to climate change; this may have significant negative impacts for agricultural production. Previous work has primarily focused on the ...impact of mean growing season temperature and precipitation on rainfed crop yields with little work on irrigated crop yields or climate extremes and their timing. County-level crop yields and daily precipitation and temperature data are pooled to quantify the impact of climate variability and extremes on four major staple crops in the United States. Conditional density plots are used to graphically explore the relationship between climate extremes and crop yields, thereby avoiding assumptions about linearity or underlying probability distributions. Non-linear and threshold-type relationships exist between yields and both precipitation and temperature climate indices; irrigation significantly reduces the impact of all climate indices. In some cases, this occurs by shifting the threshold, such that a more extreme weather event is necessary to negatively impact yields. In other cases, irrigation essentially decouples the crop yields from climate. This work demonstrates that irrigation may be a beneficial adaptation mechanism to changes in climate extremes in coming decades.
•A system dynamics model is developed to analyze eco-design policies.•Policy instruments for increased material efficiency and recovery rate are assessed.•A rebound effect caused by waste management ...policy is identified.•The model is applied to analyze the case of Latvia, an EU member state.•The packaging tax is an effective instrument to reduce material consumption.
EU's long-term objective is to become a recycling and resource effective society, where waste is utilized as a resource and waste generation is prevented. A system dynamics model was developed to analyze the policy mechanisms that promote packaging material efficiency in products through increased recycling rates. The model includes economic incentives such as packaging and landfill taxes combined with market mechanisms, behavioral aspects and ecological considerations in terms of material efficiency (the packaging material per product unit, recycled fraction in products). The paper presents the results of application of various policy instruments for increasing packaging material efficiency and recovery rate and reducing landfilled fraction. The results show that a packaging tax is an effective policy instrument for increasing the material efficiency. It ensures the decrease of the total consumption of materials and subsequent waste generation. The tax helps to counteract a rebound effect, which, as identified by the analysis, can be caused by reduced material costs due to eco-design. The model is applied to the case of Latvia. Yet, the elements and structure of the model developed are similar to waste management systems in many countries. By changing numeric values of certain parameters, the model can be applied to analyze policy mechanisms in other countries.
For a long time necrosis was thought to be an uncontrolled process but evidences recently have revealed that necrosis can also occur in a regulated manner. Necroptosis, a type of programmed necrosis ...is defined as a death receptor-initiated process under caspase-compromised conditions. The process requires the kinase activity of receptor-interacting protein kinase 1 and 3 (RIPK1 and RIPK3) and mixed lineage kinase domain-like protein (MLKL), as a substrate of RIPK3. The further downstream events remain elusive. We applied known inhibitors to characterize the contributing enzymes in necroptosis and their effect on cell viability and different cellular functions were detected mainly by flow cytometry. Here we report that staurosporine, the classical inducer of intrinsic apoptotic pathway can induce necroptosis under caspase-compromised conditions in U937 cell line. This process could be hampered at least partially by the RIPK1 inhibitor necrotstin-1 and by the heat shock protein 90 kDa inhibitor geldanamycin. Moreover both the staurosporine-triggered and the classical death ligand-induced necroptotic pathway can be effectively arrested by a lysosomal enzyme inhibitor CA-074-OMe and the recently discovered MLKL inhibitor necrosulfonamide. We also confirmed that the enzymatic role of poly(ADP-ribose)polymerase (PARP) is dispensable in necroptosis but it contributes to membrane disruption in secondary necrosis. In conclusion, we identified a novel way of necroptosis induction that can facilitate our understanding of the molecular mechanisms of necroptosis. Our results shed light on alternative application of staurosporine, as a possible anticancer therapeutic agent. Furthermore, we showed that the CA-074-OMe has a target in the signaling pathway leading to necroptosis. Finally, we could differentiate necroptotic and secondary necrotic processes based on participation of PARP enzyme.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Nonalcoholic fatty liver disease(NAFLD)is a condition in which excess fat accumulates in the liver of a patient with no history of alcohol abuse or other causes for secondary hepatic steatosis.The ...pathogenesis of NAFLD and nonalcoholic steatohepatitis(NASH)has not been fully elucidated.The"two-hit"hypothesis is probably a too simplified model to elaborate complex pathogenetic events occurring in patients with NASH.It should be better regarded as a multiple step process,with accumulation of liver fat being the first step,followed by the development of necroinflammation and fibrosis.Adipose tissue,which has emerged as anendocrine organ with a key role in energy homeostasis,is responsive to both central and peripheral metabolic signals and is itself capable of secreting a number of proteins.These adipocyte-specific or enriched proteins,termed adipokines,have been shown to have a variety of local,peripheral,and central effects.In the current review,we explore the role of adipocytokines and proinflammatory cytokines in the pathogenesis of NAFLD.We particularly focus on adiponectin,leptin and ghrelin,with a brief mention of resistin,visfatin and retinol-binding protein 4 among adipokines,and tumor necrosis factor-α,interleukin(IL)-6,IL-1,and briefly IL-18 among proinflammatory cytokines.We update their role in NAFLD,as elucidated in experimental models and clinical practice.
Understanding the temporal and spatial environmental response to past climate change during the Last Glacial-Interglacial Transition (LGIT, 16-8 ka) across Europe relies on precise chronologies for ...palaeoenvironmental records. Tephra layers (volcanic ash) are a powerful chronological tool to synchronise disparate records across the continent. Yet, some regions remain overlooked in terms of cryptotephra investigations. Building on earlier work at the same sites, we present the first complete LGIT high-resolution cryptotephra investigation of two lake records in the Carpathian Mountains in Romania, Lake Brazi and Lake Lia. Numerous volcanic glass shards have been recognised as originating from various volcanic regions, including: Iceland (Katla, Askja, and Torfajokull), Italy (Campi Flegrei, Ischia, Lipari, and Pantelleria), and central Anatolia (Acigol and Ericyes). In total, four distinct tephra horizons have now been identified in these records: 1) an LGIT Lipari tephra (11,515–12,885 cal BP, 95.4% range); 2) Askja-S (11,070–10,720 cal BP, 95.4% range); 3) an Early Holocene Lipari tephra,(12,590–10,845 cal BP, 95.4% range) and; 4) an Early Holocene Ischia tephra (11,120–10,740 cal BP, 95.4% range). The use of trace element analysis on selected cryptotephra layers provided additional important information in identifying volcanic source and facilitating correlations. These tephra layers, along with numerous other discrete cryptotephra layers, offer promise as significant future isochrons for comprehending the spatial and temporal fluctuations in past climate change throughout Europe and the Mediterranean area. This research has emphasized the significance of the Carpathian region in expanding the European and Mediterranean tephra lattice and establishing it as a keystone area within the framework.
•Far-travelled volcanic shards found in Lakes Lia and Brazi, Romania.•Geochemical correlation to three main volcanic regions: Iceland, Italy and Anatolia.•Successful use of trace element analysis for validating volcanic origins.•Significance in discovering three new, dated cryptotephra layers.•Region crucial in wider European and Mediterranean tephrostratigraphic framework.
Context: Betaine is formed from the essential nutrient choline or is supplied from the diet. It serves as a substrate in the betaine-homocysteine methyltransferase reaction and thereby provides ...methyl groups for the homocysteine-methionine cycle, which is regulated by enzymes dependent on folate, vitamin B12, riboflavin (vitamin B2), or vitamin B6.
Objective: We investigated how betaine affected total homocysteine (tHcy) concentration within the frame of variable B-vitamin status and according to the methylenetetrahydrofolate reductase (MTHFR) 677C->T genotype.
Design/Setting/Patients: This is a population-based study with a cross-sectional design. It includes 10,601 healthy men and women aged 50–64 yr.
Outcome Measures: Plasma samples were analyzed for tHcy, betaine, choline, dimethylglycine, riboflavin, and vitamin B6, whereas folate and vitamin B12 were analyzed in serum.
Results: Betaine was a strong determinant of plasma tHcy in subjects with low serum folate and the MTHFR TT genotype. The association was further strengthened at low levels in the circulation of the other B-vitamins (B2, B6, and B12). Thus, in subjects with the combination of serum folate in the lowest quartile, low vitamin B2, B6, and B12 status, and the MTHFR TT genotype, the difference in tHcy (mean, 95% confidence interval) across extreme plasma betaine quartiles was 8.8 (1.3–16.2) μmol/liter.
Conclusion: Betaine may thus be an important one-carbon source, particularly in MTHFR 677 TT subjects with inadequate B-vitamin status.
Fluorescence spectra of ZBSN5 glass (Inset: Energy levels depicting the various lasing transitions of Nd3+ ions (4F3/2→4I9/2, 11/2))
•Hypersensitive bands of Nd3+ (4I9/2→4G5/2, 2G7/2; 586nm) ions are ...shifted.•Fluorescence studies show that ZBSN glasses may be used as lasing materials.•Bi3+ cations are incorporated in the glass network as BiO6 octahedral units.
Glasses having composition 20ZnO⋅xSiO2⋅(79.5−x)Bi2O3⋅0.5Nd2O3 with x varying from 10 to 50mol% have been synthesized. The amorphous nature of the glasses was confirmed by X-ray diffraction studies. Optical absorption and fluorescence spectra were measured at ambient temperature. This paper reports on different physical and absorption spectral properties of Nd3+ doped zinc bismuth silicate glasses with varying content of Bi2O3 to understand its influences on hypersensitive band intensities. From the recorded absorption spectra, Judd–Ofelt intensity parameters Ωλ=(λ=2, 4, 6) have been evaluated with their quality factors and are used to compute the radiative properties of Nd3+ glasses. The calculated Judd–Ofelt parameters are found to decreasing with decrease in Bi2O3 content in the glass which may be due to the decrease in Nd–O bond covalency. From these intensity parameters various radiative properties like spontaneous emission probability (Arad), radiative life time (τr), fluorescence branching ratio (βr) and stimulated emission cross-section (σ) for various emission bands have been calculated. The stimulated emission cross-section of fluorescence transition 4F3/2→4I11/2 have high values and varies from 15.19×10−20cm2 to 5.73×10−20cm2 with Bi2O3 content in the host glass. The results point out this glass system as good candidate to be used in the development of photonics devices operating in the near infrared spectral range. Further, the FTIR results reveal that the glasses have BiO6, SiO4 and non-bridging oxygen as local structure.
Fluorescence spectra of ZBSS5 glass samples (inset: energy levels depicting the various lasing transitions of Sm3+ ions (4G5/2→6H7/2, 9/2, 11/2)) Display omitted .
► Optical properties of Sm3+ doped ...zinc bismuth silicate glasses have been studied. ► Transitions 4G5/2→6H7/2 and 4G5/2→6H9/2 are responsible for orange luminescence. ► Bi3+ cations are incorporated in the glass network as BiO6 octahedral units.
The glasses with compositions 20ZnO·(79.5−x)Bi2O3·xSiO2·0.5Sm2O3 (10⩽x⩽50, mol%) have been synthesized using normal melt-quench technique. Optical absorption and fluorescence spectra of the glasses were recorded at ambient temperature. Judd–Ofelt (J–O) theory has been successfully applied to characterize the absorption and luminescence spectra of these glasses. From the measured intensities of absorption bands of these glasses, the Judd–Ofelt parameters, Ωλ (λ=2, 4, 6) have been evaluated. The variation of Ω2 with Bi2O3 content has been attributed to changes in the asymmetry of the ligand field at the rare earth (RE) ion site (due to structural change) and to changes in RE–O covalency, whereas the variation of Ω6 is found to be strongly dependent on nephlauxetic effect. The shift of the hypersensitive band shows that the covalency of the RE–O decreases with decrease in Bi2O3 content in the host glass. Also, using J–O theory various radiative properties like spontaneous emission probability (Arad), radiative life time (τr), fluorescence branching ratio (βr) and stimulated emission cross-section (σ) for various emission bands of these glasses in the visible spectral region have been determined. A close correlation is observed between the Bi2O3 content and the spectroscopic, radiative and structural properties of the prepared glasses. The values of radiative properties indicated that 4G5/2→6H7/2 and 4G5/2→6H9/2 transitions responsible for orange luminescence might be used in the development of materials for LED’s and other optical devices in the visible region.
A heatwave in Siberia starting in January 2020, initiated by a wave 5 pattern in the jet stream, caused the surface air temperature to reach 38°C in June with important impacts on ecosystems and ...water resources. Here we show that this dynamical setup started a chain of events leading to this long‐lasting and unusual event: positive temperature anomalies over Siberia caused early snowmelt, leading to substantial earlier vegetation greening accompanied by decreased soil moisture and browning in the summer. This soil moisture depletion and vegetation browning, in turn, increased the impact of the heatwave on the atmosphere through a land‐atmosphere feedback. This line of evidence suggests that large‐scale dynamics and land‐atmosphere interactions both contributed to the magnitude and persistence of this record‐breaking heatwave, in addition to the background global warming impact on mean temperature. Here, we describe a carry‐over effect in Siberia from a spring positive temperature anomaly into summer dryness and browning, with retroaction into the atmosphere. With the Arctic warming twice as fast as the global average, this event foreshadows the future of northern latitude continents and emphasizes the importance of both atmospheric dynamics and land‐atmosphere interactions in the future as the climate changes. More frequent similar events could have major consequences on the carbon cycle in these carbon‐rich northern latitude regions.
Plain Language Summary
A heatwave starting January 2020 in Siberia caused temperatures to reach 38°C (100°F) in June. The winter heatwave caused an early snow melt which elevated the soil moisture. This in turn caused earlier spring greening. As the heatwave persisted, soil moisture evaporated causing soil to be drier and trees to brown earlier in summer. Since the soil was drier than normal, the heat emanating from it was elevated which further exacerbated the heatwave. With arctic temperatures increasing twice as fast as the global average, the role of land‐atmosphere interactions we describe will likely become more prominent in the future as the climate warms.
Key Points
Early warming favored early snowmelt, leading to earlier soil moisture availability and enhanced terrestrial greenness
Soil moisture was depleted in late summer, leading to a drop in terrestrial greenness and increased browning
The browning and reduced soil moisture in summer reduced evapotranspiration and increased sensible heat flux, further fueling the heatwave
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