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Contemporary studies of conflict have adopted approaches that minimize the importance of negotiation during war or treat it as a constant and mechanical activity. This is strongly related to the lack of systematic data that track and illustrate the complex nature of wartime diplomacy. I address these issues by creating and exploring a new daily-level data set of negotiations in all interstate wars from 1816 to the present. I find strong indications that post-1945 wars feature more frequent negotiations and that these negotiations are far less predictive of war termination. Evidence suggests that increased international pressures for peace and stability after World War II, especially emanating from nuclear weapons and international alliances, account for this trend. These original data and insights establish a dynamic research agenda that enables a more policy-relevant study of conflict management, highlights a historical angle to conflict resolution, and speaks to the utility of viewing diplomacy as an essential dimension to understanding war.
Nondestructive means for estimating air potato (also known as air yam; Dioscorea bulbifera L.) biomass will help gauge its management efficacy over time. We developed allometric equations to estimate total and fractional biomass components and densities of aerial bulbils and underground tubers of field-grown D. bulbifera in Florida. We selected four naturally infested sites representing its southern, central, and northern distribution in Florida and measured three independent variables (vine densities, stem diameters, and top heights) of 84 (21 site−1) discrete D. bulbifera patches during late October to early December of 2012. We destructively harvested D. bulbifera biomass, sorted by tubers, stems, leaves, and bulbils; counted units of bulbils and underground tubers (dependent variables); and dried to a constant weight. Mean percentages of tuber, stem, leaf, and bulbil fractions in total biomass were 42.0, 15.6, 26.0, and 16.4, respectively. We developed a parameterized multiplicative prediction model and regression equation for each dependent variable. Slopes of relationships among independent and dependent variables varied by biomass and density (bulbil and tuber) of plant components. Multiplied values of independent variables: all three for total, tuber, stem, and leaf biomass; two (vine base diameter*patch height) for bulbil biomass; two (vine density*patch height) for bulbil density; and only one (stem density) for tuber density provided best (R2-based) prediction values. These models will provide nondestructive methods for estimating biomass components and density of vegetative propagules of naturally growing D. bulbifera. Models are critical for understanding the performance of D. bulbifera in its exotic range, estimating biomass to project control costs, and comparing biomass components and bulbil/tuber densities during pre- and postmanagement periods to gauge control efficacy.
Despite its established benefits, palliative care (PC) is not well known among patients and family/caregivers. From a nationally representative survey, we sought to assess the following associated with PC: knowledge, knowledge sources, and beliefs.
Data were drawn from the Health Information National Trends Study (HINTS 5 Cycle 2), a cross-sectional, survey of non-institutionalized adults aged 18+ years in the USA. Data were weighted and assessed by proportional comparison and multivariable logistic regression.
A total of 3504 respondents were identified, and approximately 29% knew about PC. In the adjusted model, less PC knowledge was associated with: lower age (those aged <50), male gender, lower education (<high school graduation or high school graduate), and non-internet users. A little over half (55%) of respondents accessed healthcare providers first for PC information, and 80% considered providers the most trusted source of PC information. Most of the participants strongly/somewhat agreed that the goal of PC is to help friends and family cope with a patient's illness (90.6%), offer social and emotional support (93.4%), and manage pain and other physical symptoms (95.1%). Similarly, a majority (83.3%) strongly/somewhat agreed that it is a doctor's obligation to inform all patients with cancer about the option of PC.
Significance of results
PC knowledge was generally low (1-in-3 respondents knew of PC), with significant differences according to age, gender, education, and internet use. These data provide a baseline from which PC education policies and interventions may be measured.
Crisis bargaining literature has predominantly used formal and
qualitative methods to debate the relative efficacy of actions,
public words, and private words. These approaches have overlooked
the reality that policymakers are bombarded with information and
struggle to adduce actual signals from endless noise. Material
actions are therefore more effective than any diplomatic
communication in shaping elites’ perceptions. Moreover, while
ostensibly “costless,” private messages provide a more precise
communication channel than public and “costly” pronouncements. Over
18,000 declassified documents from the Berlin Crisis of 1958–63
reflecting private statements, public statements, and White House
evaluations of Soviet resolve are digitized and processed using
statistical learning techniques to assess these claims. The results
indicate that material actions have greater influence on the White
House than either public or private statements; that public
statements are noisier than private statements; and that private
statements have a larger effect on evaluations of resolve than
The neuropsychological origins of negative syndrome of schizophrenia remain elusive. Evidence from behavioural studies, which utilised emotion-inducing pictures to elicit motivated behaviour generally reported that that schizophrenia patients experienced similar affective experience as healthy individuals but failed to translate emotional salience to motivated behaviour, a phenomenon called emotion–behaviour decoupling. However, a few studies have examined emotion–behaviour decoupling in non-psychotic high-risk populations, who are relatively unaffected by medication effects.
In this study, we examined the nature and extent of emotion–behaviour decoupling in in three independent samples (65 schizophrenia patients v. 63 controls; 40 unaffected relatives v. 45 controls; and 32 individuals with social anhedonia v. 32 controls). We administered an experimental task to examine their affective experience and its coupling with behaviour, using emotion-inducing slides, and allowed participants to alter stimulus exposure using button-pressing to seek pleasure or avoid aversion.
Schizophrenia patients reported similar affective experiences as their controls, while their unaffected relatives and individuals with high levels of social anhedonia exhibited attenuated affective experiences, in particular in the arousal aspect. Compared with their respective control groups, all of the three groups showed emotion–behaviour decoupling.
Our findings support that both genetically and behaviourally high-risk groups exhibit emotion–behaviour decoupling. The familial association apparently supports its role as a putative trait marker for schizophrenia.
Dioscorea bulbifera is a serious invader of various ecosystems in Florida, where plants generated by its two morphotypes climb aggressively and smother supporting vegetation. There is a dearth of published research on its invasive biological attributes including vine growth and biomass production by plants generated from bulbils. Herein, we assessed these parameters in common garden studies by planting bulbils from four biomass categories (PBBCs I–IV) of both morphotypes. Vine lengths, longevity-based growth rates (VLGR), biomass, and quantities of leaves and daughter bulbils in both morphotypes showed positive correlation with the biomass of planted parental bulbils. This indicated similarity between corresponding attributes in two morphotypes. Total vine length showed strong positive correlation with VLGR, biomass, and quantities of leaves and bulbils. Overall vine longevity among plants from PBBCs I–IV did not significantly differ whereas the total vine lengths, VLGRs, number of branches, and quantities of leaves and bulbils increased with the biomass of the parental bulbils. Plants recruited by smaller bulbils allocated more biomass to leaves and tubers compared to stems and bulbils, whereas the plants recruited by larger bulbils allocated more biomass to leaves and bulbils compared to tubers and stems. Higher proportion of biomass allocation to leaves and bulbils presumably ensures immediate faster growth, longer vines, and a greater number of daughter bulbils for future recruitment of new plants. Vine length (associated with faster growth rate, capable of blanketing supporting structures and producing large quantities of bulbils) has been noted as the primary invasive biological attribute that facilitates D. bulbifera's status as a noxious exotic weed in Florida. Control measure that can reduce vine length should reduce or eliminate the invasive behavior of D. bulbifera in Florida.
Traditional near-field antenna measurements use the sampling theorem to reconstruct the antenna pattern perfectly. However, a large number of measurement points are required for this approach. To address this problem, in this study, we propose a technique to accelerate the near-field antenna measurement, which is achieved by sparse E-field sampling in the region where the E-field changes smoothly and dense sampling in the region where the field changes rapidly. Further, our approach ensures robustness of measurement; the E-field information need not be known before carrying out measurements. Our experimental results demonstrate that our technique can reduce the number of measuring points by at least 64.9% when measuring two different patterns (15-GHz horn antenna with θ = 0° and 10°).
We are reporting on stress engineering utilizing AlN/GaN superlattices (SLs) for epitaxy of GaN layers on 200 mm silicon substrates carried out in Veeco's Propel™ rotating disk, single wafer metal organic chemical vapor deposition (MOCVD) reactor. The Turbodisc® reactor is designed to have homogeneous alkyl/hydride flow distribution and uniform temperature profile, which translate into excellent uniformity and concentric symmetry in epilayer thickness and alloy composition. This feature results in uniform and controllable stress in epilayers across large-size substrates. Crack-free 2 μm GaN layers were grown on 200 mm Si using uniformly strained AlN/GaN SLs with periods of 3–5 and 10–30 nm, respectively. Compressive and tensile stress can be precisely adjusted by changing the thickness of the AlN and GaN layers in the SLs, resulting in controllable wafer curvature/bow after cool down. For a fixed period thickness structure, the effects of growth conditions, such as growth rate of GaN, AlN V/III ratio, and growth temperature, on wafer stress were investigated.
Several Gigantopithecus faunas associated with taxonomically undetermined hominoid fossils and/or stone artifacts are known from southern China. These faunas are particularly important for the study of the evolution of humans and other mammals in Asia. However, the geochronology of the Gigantopithecus faunas remains uncertain. In order to solve this problem, a program of geochronological studies of Gigantopithecus faunas in Guangxi Province was recently initiated. Chuifeng Cave is the first studied site, which yielded 92 Gigantopithecus blacki teeth associated with numerous other mammalian fossils. We carried out combined ESR/U-series dating of fossil teeth and sediment paleomagnetic studies. Our ESR results suggest that the lower layers at this cave can be dated to 1.92 ± 0.14 Ma and the upper layers can be dated to older than 1.38 ± 0.17 Ma. Correlation of the recognized magnetozones to the geomagnetic polarity timescale was achieved by combining magnetostratigraphic, biostratigraphic and ESR data. The combined chronologies establish an Olduvai subchron (1.945–1.778 Ma) for the lowermost Chuifeng Cave sediments. We also analyzed the enamel δ13C values of the Gigantopithecus faunas. Our results show that southern China was dominated by C3 plants during the early Pleistocene and that the Gigantopithecus faunas lived in a woodland-forest ecosystem.
Stress control using AlN/GaN superlattices (SLs) for epitaxy of GaN on 200 mm Si (111) substrates is reported. Crack-free 2 μm GaN layers were grown over structures containing 50 to 100 pairs of 3-5 nm AlN/10-30 nm GaN SLs. Compressive and tensile stress can be precisely adjusted by changing the thickness of the AlN and GaN layers in the SLs. For a constant period thickness, the effects of growth conditions, such as growth rate of GaN, V/III ratio during AlN growth, and growth temperature, on wafer stress were investigated.
Detailed understanding of growth termination in vertically aligned single-walled carbon nanotubes (SWNTs) made via supergrowth, or water-assisted growth, remains critical to achieving the ultralong SWNTs necessary for next-generation applications. We describe the irreversible catalyst morphology evolution that occurs during growth, and which limits the lifetime of surface supported catalysts. Growth termination is strongly dependent on growth temperature, but not sensitive to C2H2:H2O ratio. In addition to both planar Ostwald ripening of small (sub-5 nm) Fe catalyst particles and diffusion of metal atoms into the alumina support, other features that contribute to growth termination or deceleration are described, including center-of-mass particle motions and coalescence of smaller species of surface supported Fe nanoparticles. Additionally, a temperature-induced structural transition in the alumina catalyst support is found to be coincident with abrupt growth termination at temperatures of 800 °C and higher. In situ electron microscopy observations are used to directly support these observations.
The influence of the type of alumina used as catalyst support on the evolution, activity, and lifetime of the catalyst during water-assisted CVD growth (or ‘supergrowth') of single-walled carbon nanotube (SWNT) carpets has been studied. The catalyst consisted of a thin Fe film supported on alumina films deposited by different methods: atomic layer deposition (ALD), e-beam, and magnetron sputtering. In order to fully understand the influence of the type of alumina on SWNT carpet growth, crystalline alumina (c-cut sapphire) and annealed alumina deposited by e-beam were also used as catalyst supports. The activity and lifetime of Fe catalyst during SWNT carpet growth showed a strong dependence on the type of alumina used as support. Fe supported on sputtered alumina (sputtered/Fe) showed the highest catalytic activity and lifetime, which was closely followed by e-beam/Fe while Fe supported on sapphire (sapphire/Fe) showed the least catalytic activity and lifetime. AFM, XPS depth profile, variable angle spectroscopic ellipsometry (VASE) studies revealed that the catalyst evolution and the porosity of the different alumina supports correlate with the lifetime and activity of the catalysts.
The effect of microstructural inhomogeneities with different length scale on the plasticity of (Ti45Zr16Be20Cu10Ni9)100–xTax (x = 0, 5, and 10) bulk glassy alloys has been studied. The formation of specific heterogeneous microstructures with a different type of structural inhomogeneity, i.e., short-/medium-range ordered clusters or micrometer-scale ductile dendrites combined with a glassy matrix, evolved by appropriately tuning the alloy chemistry, improves the room temperature plasticity up to ∼12.5% and ∼15%, respectively. The pronouncedly enhanced plasticity is mainly attributed to the retardation of shear localization and multiplication of shear bands by controlling the plastic and failure instabilities otherwise responsible for premature failure.
Instrumented indentation is often used in the study of small-scale mechanical behavior of “soft” matters that exhibit viscoelastic behavior. A number of techniques have been used to obtain the viscoelastic properties from quasi-static or oscillatory indentations. This paper summarizes our recent findings from modeling indentation in linear viscoelastic solids. These results may help improve methods of measuring viscoelastic properties using instrumented indentation techniques.
When an electric field is applied to a ferroelectric the crystal lattice spacing changes as a result of the converse piezoelectric effect. Although the piezoelectric effect and polarization switching have been investigated for decades there has been no direct nanosecond-scale visualization of these phenomena in solid crystalline ferroelectrics. Synchrotron x-rays allow the polarization switching and the crystal lattice distortion to be visualized in space and time on scales of hundreds of nanometers and hundreds of picoseconds using ultrafast x-ray microdiffraction. Here we report the polarization switching visualization and polarization domain wall velocities for Pb(Zr0.45Ti0.55)O3 thin film ferroelectric capacitors studied by time-resolved x-ray microdiffraction.
The evolution of stored ferroelectric polarization in PZT thin film capacitors was imaged using synchrotron x-ray microdiffraction with a submicron-diameter focused incident x-ray beam. To form the capacitors, an epitaxial Pb(Zr,Ti)O3 (PZT) thin film was deposited on an epitaxially-grown conductive SrRuO3 (SRO) bottom electrode on a SrTiO3 (STO) (001) substrate. Polycrystalline SRO or Pt top electrodes were prepared by sputter deposition through a shadow mask and subsequent annealing. The intensity of x-ray reflections from the PZT film depended on the local ferroelectric polarization. With 10 keV x-rays, regions of opposite polarization differed in intensity by 26% in our PZT capacitor with an SRO top electrode. Devices with SRO electrodes showed just a 25% decrease in the remnant polarization after 107 switching cycles. In devices with Pt top electrodes, however, the switchable polarization decreased a by 70% after only 5×104 cycles.