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Under what conditions can UN military peacekeeping operations (PKOs) succeed in contexts of civil war? This is an important question given the prevalence and cost of civil wars and the high, yet not always fulfilled, expectations of very costly military PKOs as responses to them by the international community. Yet, the academic and policy debates on this question are as long-standing as they are unresolved. Our article contributes to existing scholarship in several ways. First, adopting a nuanced and multi-dimensional definition of success that considers violence, displacement, and contagion as its 3 essential components, we identified 19 cases of full or partial successes, and 13 full or partial failures, covering all 32 UN military PKOs deployed to civil war settings. Second, we develop an original dataset and analytical framework that identifies a wide range of plausible factors related to the dynamics of both the intervention and the underlying conflict it is meant to address. Third, applying qualitative comparative analysis to our dataset of these 32 military PKOs, our key finding is that what matters most and consistently across all of these missions is the presence or absence of domestic consent to, and cooperation with, deployed PKOs.

The atmospheric oxidation of biogenic volatile organic compounds (BVOC) by OH radicals over tropical rainforests impacts local particle production and the lifetime of globally distributed harmful and radiatively active gases. For the pristine Amazon rainforest during the dry season, we empirically determined the diurnal OH radical variability at the forest-atmosphere interface region between 80 and 325m from 07:00 to 15:00 LT using BVOC measurements. A dynamic time warping approach was applied showing that median averaged transport times between 80 m to 325 m decrease from 105 to 15 minutes over this time period. The inferred OH concentrations show evidence for an early morning OH peak (07:00–08:00 LT) and an OH maximum (13:00–14:00LT) reaching 1x106 ± 1.1x106 molecules cm− 3 controlled by the coupling between BVOC emission fluxes, convective turbulence, air chemistry and photolysis rates. The results were evaluated against a turbulence resolving transport (DALES), a regional scale (WRF-Chem) and a global (EMAC) atmospheric chemistry model.

Este capítulo resume nuestra comprensión de los ciclos de tres elementos biogeoquímicos clave en la Amazonía (carbono, nitrógeno y fósforo), que abarcan tanto los ecosistemas terrestres como los acuáticos. Históricamente, el bioma amazónico intacto ha sido un importante sumidero de carbono, aunque este sumidero parece estar debilitándose con el tiempo.

Covalent functionalization of two‐dimensional molybdenum disulfide (2D MoS2) holds great promise in developing robust organic‐MoS2 hybrid structures. Herein, for the first time, we demonstrate an approach to building up a bisfunctionalized MoS2 hybrid structure through successively reacting activated MoS2 with alkyl iodide and aryl diazonium salts. This approach can be utilized to modify both colloidal and substrate supported MoS2 nanosheets. We have discovered that compared to the adducts formed through the reactions of MoS2 with diazonium salts, those formed through the reactions of MoS2 with alkyl iodides display higher reactivity towards further reactions with electrophiles. We are convinced that our systematic study on the formation and reactivity of covalently functionalized MoS2 hybrids will provide some practical guidance on multi‐angle tailoring of the properties of 2D MoS2 for various potential applications., For the first time, we demonstrate an approach to building up a bisfunctionalized MoS2 hybrid structure through successively treating activated MoS2 with alkyl iodide and aryl diazonium salt. This approach can be used to modify both colloidal and substrate‐supported MoS2 nanosheets.

This study combines ground-based gas phase, particle, and rainfall measurements at the ATTO site to study the impact of rainfall events on greenhouse and reactive gas concentrations and discuss how this process is relevant for producing new particles. Measurements of CO2, CH4, CO, O3, NO, and NO2 concentrations were collected from the surface to 79m using a tower at the ATTO site in the central Amazon forest northeast of Manaus, Brazil. Particle size distribution was measured by an SMPS and rainfall by a rain gauge at the top of the tower. Data collection started in 2012, and this analysis covered the period up to 2020. The 30-minute interval dataset was used to study how convective events modify the concentration of these gases. During the rainfall events, CO2, CO, and CH4 concentrations decrease, though CH4 varies less with height than CO and CO2. The daily cycle of NO2 presents an interesting characteristic showing distinct daily evolution for the concentration in the upper and lower levels. The decrease in NO2 concentration in the upper level and the increase near the surface in the afternoon, which is the typical time of rainfall events, indicate that a specific process occurs near the surface. With the joint analysis of gas-phase observations with ultrafine particles and rainfall data, it was possible to evaluate the interesting physical-chemical processes occurring during the rainfall events that might be important for particles nucleation. The time of rainfall events was defined as the first-time rain rate reaching 3 mm/hours, a typical value of the beginning of convective rainfall events. Interestingly, during rainfall events, there is a significant injection of O3 above and inside the canopy, and at this moment, its concentrations can increase by 300%. At the same time, NO decreases, and NO2 increases its concentration, suggesting a reaction between NO and O3 forming NO2. The concentration of NO2 follows the increase in particle concentration smaller than 20nm. This result opens new perspectives on the role of new particle formation related to rain and vertical mixing in the Amazon.

The vegetation and soils of the Amazon contain large amounts of carbon that may be vulnerable to loss given ongoing climate and land use change in the Amazon basin. Previous studies predicted that the Amazon rainforest would start to act as a net carbon source to the atmosphere by 2030-2040, and that it has switched from being a sink to source over the last decade. Using data from eddy covariance and vertical carbon dioxide profile measurement systems installed at the 80 m walk-up tower in the Amazon Tall Tower Observatory (ATTO) site, located in well-preserved central Amazon upland rainforest, we assessed net ecosystem exchange (NEE), gross primary productivity (GPP), and ecosystem respiration (Reco) for the period 2014-2019. The NEE results indicate that the central Amazon upland rainforest was carbon neutral or a source during this 6-year period. Seasonal GPP variations were related to soil water availability and vapor pressure deficit. The strong 2015-2016 El Niño event decreased both GPP and Reco due to the unusually long dry period, but also contributed to carbon flux dynamics in post El Niño periods. In the 2017-dry season, we measured higher dry-season GPP compared with the other years, which we hypothesize was triggered by photosynthesis activation in sub-canopy and understory trees. This is supported by the minimum green crown fraction at upper canopy trees, indicating more light availability in lower canopy trees, and the higher fraction of absorbed photosynthetically active radiation, both recorded during the dry-season of 2017. Our results show that the ground-based measurement setup at ATTO is well suited to investigate the local carbon fluxes on seasonal to interannual time scales.

New particle formation (NPF), referring to the nucleation of molecular clusters and their subsequent growth into the cloud condensation nuclei (CCN) size range, is a globally significant and climate-relevant source of atmospheric aerosols. Classical NPF exhibiting continuous growth from a few nanometers to the Aitken mode around 60–70 nm is widely observed in the planetary boundary layer (PBL) around the world but not in central Amazonia. Here, classical NPF events are rarely observed within the PBL, but instead, NPF begins in the upper troposphere (UT), followed by downdraft injection of sub-50 nm (CN) particles into the PBL and their subsequent growth. Central aspects of our understanding of these processes in the Amazon have remained enigmatic, however. Based on more than 6 years of aerosol and meteorological data from the Amazon Tall Tower Observatory (ATTO; February 2014 to September 2020), we analyzed the diurnal and seasonal patterns as well as meteorological conditions during 254 of such Amazonian growth events on 217 event days, which show a sudden occurrence of particles between 10 and 50 nm in the PBL, followed by their growth to CCN sizes. The occurrence of events was significantly higher during the wet season, with 88 % of all events from January to June, than during the dry season, with 12 % from July to December, probably due to differences in the condensation sink (CS), atmospheric aerosol load, and meteorological conditions. Across all events, a median growth rate (GR) of 5.2 nm h−1 and a median CS of 1.1 × 10−3 s−1 were observed. The growth events were more frequent during the daytime (74 %) and showed higher GR (5.9 nm h−1) compared to nighttime events (4.0 nm h−1), emphasizing the role of photochemistry and PBL evolution in particle growth. About 70 % of the events showed a negative anomaly of the equivalent potential temperature (Δθe′) – as a marker for downdrafts – and a low satellite brightness temperature (Tir) – as a marker for deep convective clouds – in good agreement with particle injection from the UT in the course of strong convective activity. About 30 % of the events, however, occurred in the absence of deep convection, partly under clear-sky conditions, and with a positive Δθe′ anomaly. Therefore, these events do not appear to be related to downdraft transport and suggest the existence of other currently unknown sources of sub-50 nm particles.

This paper introduces the new dataset of Political Agreements in Internal Conflicts (PAIC) and presents its first application. PAIC captures the institutional provisions in political agreements concluded between 1989 and 2016. It provides information on 91 variables, along five dimensions: power sharing, transitional justice, cultural institutions, territorial self-governance and international assistance. First, the paper presents the data collection and coding procedures. Then it replicates Hartzell’s and Hoddie’s (2007, Crafting Peace, The Pennsylvania State University Press) seminal study on the relationship between power sharing and negotiated agreements, showing the long-term importance of a previously overlooked realm: commissions.

Focusing on process tracing and using the example of fieldwork in Donbas, I develop an argument on what theoretically grounded and empirically detailed methodological solutions can be considered to mitigate the challenges of research on conflict zones and assure the robustness of any causal claims made. I first outline my assumptions about process tracing as the central case study method and its application to research on conflict zones, and then discuss in more detail data requirements, data collection, and data analysis. Using two examples of case studies on the war in and over Donbas, I illustrate how three standards of best-practice in process tracing—the need for a theory-guided inquiry, the necessity to enhance causal inference by paying attention to (and ruling out) rival explanations, and the importance of transparency in the design and execution of research—can be applied in the challenging circumstances of fieldwork-based case studies of conflict zones. I conclude by suggesting that as a minimum threshold for reliance upon causal inferences, these three standards also should align with a standard of evidence that requires both the theoretical and empirical plausibility of any conclusions drawn.

Did US drone strikes cause the unravelling of the Pakistani conflict settlement process between the government and the TTP in 2013-14? In answering this question, we present strong, fieldwork-based...

Academic and policy literature on the post-Soviet region’s protracted conflicts frequently assumes that trade is an effective confidence-building measure (CBM) and as such also has the potential to...

This chapter summarizes the cycles of three key biogeochemical elements, carbon, nitrogen and phosphorus, with a focus on carbon, spanning both terrestrial and aquatic ecosystems in Amazon. The chapter also examines the emissions of two key trace gases which make substantial contributions to radiative warming, methane and dinitrogen oxide, and summarizes trace gas and aerosol emissions from the Amazon and their impact on atmospheric pollution, cloud properties, and water cycling.

New particle formation (NPF), referring to the nucleation of molecular clusters and their subsequent growth into the cloud condensation nuclei (CCN) size range, is a globally significant and climate-relevant source of atmospheric aerosols. Classical NPF exhibiting continuous growth from a few nanometers to the Aitken mode around 60–70 nm is widely observed in the planetary boundary layer (PBL) around the world, but not in central Amazonia. Here, classical NPF events are rarely observed in the PBL, but instead, NPF begins in the upper troposphere (UT), followed by downdraft injection of sub-50 nm (CN

Nocturnal turbulent kinetic energy (TKE) and fluxes of energy, CO2 and O3 between the Amazon forest and the atmosphere are evaluated for a 20-day campaign at the Amazon Tall Tower Observatory (ATTO) site. The distinction of these quantities between fully turbulent (weakly stable) and intermittent (very stable) nights is discussed. Spectral analysis indicates that low-frequency, nonturbulent fluctuations are responsible for a large portion of the variability observed on intermittent nights. In these conditions, the low-frequency exchange may dominate over the turbulent transfer. In particular, we show that within the canopy most of the exchange of CO2 and H2O happens on temporal scales longer than 100 s. At 80 m, on the other hand, the turbulent fluxes are almost absent in such very stable conditions, suggesting a boundary layer shallower than 80 m. The relationship between TKE and mean winds shows that the stable boundary layer switches from the very stable to the weakly stable regime during intermittent bursts of turbulence. In general, fluxes estimated with long temporal windows that account for low-frequency effects are more dependent on the stability over a deeper layer above the forest than they are on the stability between the top of the canopy and its interior, suggesting that low-frequency processes are controlled over a deeper layer above the forest. Made available in DSpace on 2018-05-19T00:37:32Z (GMT). No. of bitstreams: 1 OliveiraACP2018.pdf: 2710275 bytes, checksum: 065c833d026306778501730602111723 (MD5) Previous issue date: 2018-05-18

Purpose Allodynia refers to pain evoked by physiologically innocuous stimuli. It is a disabling symptom of neuropathic pain following a lesion within the peripheral or central nervous system. In fact, two different pathophysiological mechanisms of cold allodynia (ie, hypersensitivity to innocuous cold) have been proposed. The peripheral sensitization of nociceptive neurons can produce cold allodynia, which can be induced experimentally by a topical application of menthol. An alternative mechanism involves reduced inhibition of central pain processing by innocuous cold stimuli. A model to induce the latter type of allodynia is the conduction block of peripheral A-fiber input. Patients and methods In the presented study, functional MRI was used to analyze these two different experimental models of cold allodynia. In order to identify the underlying cerebral activation patterns of both mechanisms, the application of menthol and the induction of a mechanical A-fiber blockade were studied in healthy volunteers. Results The block-induced cold allodynia caused significantly stronger activation of the medial polymodal pain processing pathway, including left medial thalamus, anterior cingulate cortex, and medial prefrontal cortex. In contrast, menthol-induced cold allodynia caused significantly stronger activity of the left lateral thalamus as well as the primary and secondary somatosensory cortices, key structures of the lateral discriminative pathway of pain processing. Mean pain intensity did not differ between both forms of cold allodynia. Conclusion Experimental cold allodynia is mediated in different cerebral areas depending on the underlying pathophysiology. The activity pattern associated with block-induced allodynia confirms a fundamental integration between painful and non-painful temperature sensation, ie, the cold-induced inhibition of cold pain.

The pristine Amazon rainforest is a unique place to study ozone (O3) deposition rates and tropospheric transport, due to the absence of nearby sources of anthropogenic pollution. Parts of the low background O3 are considered to be transported from the stratosphere into the troposphere. This occurs due to general entrainment of stratospheric air at the tropopause. Within the troposphere, downdrafts provide effective vertical mixing and are known to increase surface O3 values. Low-level jets can also enhance O3 concentrations due to long range transport and locally induced mixing in the nocturnal boundary layer. Therefore, we study these phenomena based on long term datasets from 2012 to present from tall measurements towers (80 m and 325 m).Ozone mixing ratios were measured at the ATTO site (Amazon Tall Tower Observatory) in the Central Amazon (02°08’38.8’’S, 58°59’59.5’’W) since 2012 at 8 different heights between 5 cm and 80 meters and additional measurements from 80 m up to 325 meters are running since 2017. From 2015 to 2017, 3-dimensional wind measurements have been performed in 150 meters height in 10 Hz sampling rate, showing evidences for the formation of a nocturnal low-level jet (LLJ), which leads to higher turbulent mixing inside the residual layer/ stable nocturnal layer. We were comparing the nocturnal LLJ with downdrafts of air due to strong thunderstorms which led to increases of O3 as well. We are analyzing these events regarding their in-canopy air exchange, their frequency and seasonality and comparing them with the effects of the nocturnal LLJ. As the data series comprises more than eight years of data we are also analyzing the interannual variability.

Primary biological aerosol particles (PBAP), better known as bioaerosols, are considered to play a role in atmospheric and climate influencing processes. Fungal spores, as a part of PBAP, account for a large fraction of coarse particulate matter in some ecosystems, as for example the Amazon rainforest. In such highly diverse ecosystems, fungi play key roles as mycorrhizal fungi for nutrient uptake of plants and as decomposers in nutrient and water cycling, and thus their community structure strongly influences local ecosystem conditions. Despite this relevance, fungal spore emission patterns under natural conditions and the corresponding triggering factors are not well characterized, yet. In this study, we present a laboratory and field measurement techniques to quantify and analyze bioaerosol emission patterns and the effect of precipitation on fungal spore emission.For investigations under field conditions, the particle emissions of fungi (Agaricomycetes) were characterized at their site of growth in the field using an optical particle sizer and a data logger. Particle concentrations and their size distribution (0.3 to 10 µm), as well as the microclimatic temperature and humidity were measured in close vicinity to the fungal fruiting body. Generally, field measurements were performed over a time span of 24 h with some exceptions ranging up to 6 days. For laboratory measurements, a newly developed glass chamber system was used to measure particle emissions of fungi under controlled conditions. During the chamber measurements, the humidity and temperature conditions were varied and recorded with a datalogger. To simulate precipitation events, the fruiting bodies were sprayed with water between measurement sections and particle emissions were monitored before and after moistening.First measurements of fungi under field and lab conditions showed that high humidity values were necessary to trigger fungal spore emissions. In many cases, precipitation events and the moisture status of the fungus and substrate had an influence on spore release. Based on the results of 47 field measurements, it was possible to establish a function simulating the spore emission patterns of fungi during their diurnal emission cycle. During field measurements, an emission of up to 55,000 spores per second was recorded directly at the fungus, which, according to the function, may correspond to emissions of up to 2.8 x 109 spores per day. Chamber measurements showed that spore emissions generally started 2-3 hours after artificial moistening.Increasing deforestation is expected to cause drier conditions and to increase the possibility of droughts, which will have an impact on the species composition and quantity of fungi in the Amazon. A combination of our field and lab emission data is expected to allow a new interpretation of bioaerosol emissions and composition in the Amazon, which can be used as a baseline to analyze the potential relevance of bioaerosols in regional atmosphere and climate processes.