Northern Hemisphere Glaciation during the Globally Warm Early Late Pliocene

The early Late Pliocene (3.6 to ~3.0 million years ago) is the last extended interval in Earth's history when atmospheric CO2 concentrations were comparable to today's and global climate was warmer. Yet a severe global glaciation during marine isotope stage (MIS) M2 interrupted this phase of global warmth ~3.30 million years ago, and is seen as a premature attempt of the climate system to establish an ice-age world. Here we propose a conceptual model for the glaciation and deglaciation of MIS M2 based on geochemical and palynological records from five marine sediment cores along a Caribbean to eastern North Atlantic transect. Our records show that increased Pacific-to-Atlantic flow via the Central American Seaway weakened the North Atlantic Current and attendant northward heat transport prior to MIS M2. The consequent cooling of the northern high latitude oceans permitted expansion of the continental ice sheets during MIS M2, despite near-modern atmospheric CO2 concentrations. Sea level drop during this glaciation halted the inflow of Pacific water to the Atlantic via the Central American Seaway, allowing the build-up of a Caribbean Warm Pool. Once this warm pool was large enough, the Gulf Stream–North Atlantic Current system was reinvigorated, leading to significant northward heat transport that terminated the glaciation. Before and after MIS M2, heat transport via the North Atlantic Current was crucial in maintaining warm climates comparable to those predicted for the end of this century

An experimental study towards the practical application of closed-loop flat-plate pulsating heat pipes

The thermal performance of a flat-plate closed-loop pulsating heat pipe (PHP) is experimentally obtained. The PHP is manufactured by means of CNC-milling and vacuum brazing of a stainless steel 316L bottom plate and lid. Each channel of the PHP has a 2×2 mm2 square cross section. In total 12 channels (6 turns) fit in the 50×200 mm2 effective area of the PHP. During the experimental investigation, the power input is increased from 20W to 100W through a 50×50 mm2 evaporator section, while cooling is performed through a 50×50 mm2 condenser section with the use of a Thermo-Electric Cooler (TEC). The PHP is charged with methanol with 40% filling ratio. The thermal resistance is obtained for different inclination angles. It is observed that the 6-turn device operates well in vertical orientation. It however does not operate horizontally. Moreover, experiments have shown that the operating orientation is between 15-30°. The overall thermal resistance was determined at 0.48 K/W for a 100 W power input in the vertical evaporator-down orientation

The Information Value of Full-Retention Policies

Discard rates in marine fisheries have been estimated at more than 80% for some individual fisheries, with an average global discard rate of 8%. Discarding of catch can be problematic for three main reasons: (1) in the absence of accurate and precise discards estimates, unreliable catch data distort estimation of the appropriate quotas; (2) bycatch imposes a cost on the resource as survival rates are generally low; and (3) bycatch-induced mortality of charismatic species presents a loss of non-use values. Policy instruments to limit discarding vary from taxes on bycatch, to subsidies for selective fishing gear, to outright bans on discarding, also called full-retention policies. The 2013 reform of the European Union's Common Fisheries Policy features the introduction of such an obligation to land all catches "of species which are subject to catch limits." In this paper we aim to estimate the economic effects of a full retention policy in a mixed fishery. More specifically, we estimate the economic value of the data distortion caused by discarding of fish, and how these economic losses are ameliorated by a ban on discards. We present a bioeconomic model capable of investigating these questions in a mixed fishery for a variety of stock assessment methods, harvest control rules, and discarding policies. We apply the model to the North Sea demersal fishery, focusing on the two main commercial species plaice (pleuronectes platessa) and sole (solea solea). We find that the information value of discard bans depends largely on the prevailing harvest control rule.Keywords: Poor Data and Uncertainty, Fisheries Economics, Modeling and Economic Theor

Effectiveness and cost-effectiveness of a nurse-delivered intervention to improve adherence to treatment for HIV : a pragmatic, multicentre, open-label, randomised clinical trial

This trial was funded from public money by the Netherlands Organisation for Health Research and Development (ZonMW; grant number 171002208). Aardex provided support on the development of the study website. We thank all the HIV nurses and physicians from the seven HIV clinics involved in the AIMS study for their input and collaboration (Academic Medical Centre, Slotervaart hospital, and St. Lucas-Andreas hospital, all in Amsterdam; the Leiden University Medical Centre, Leiden; HAGA hospital, The Hague; Erasmus Medical Centre, Rotterdam; and Isala clinic, Zwolle), the study participants, and the Stichting HIV Monitoring (SHM) for their support in accessing the SHM database for identifying patient inclusion criteria and developing the Markov model. Finally, we thank and remember Herman Schaalma (deceased) for his contribution to the study design and grant application.Peer reviewedPostprin

Postural change in volunteers: sympathetic tone determines microvascular response to cardiac preload and output increases

Purpose: Microvascular perfusion may be a non-invasive indicator of fluid responsiveness. We aimed to investigate which of the microvascular perfusion parameters truly reflects fluid responsiveness independent of sympathetic reflexes. Methods: Fifteen healthy volunteers underwent a postural change from head up tilt (HUT) to the supine position, diminishing sympathetic tone, followed by a 30° passive leg raising (PLR) with unaltered tone. Prior to and after the postural changes, stroke volume (SV) and cardiac output (CO) were measured, as well as sublingual microcirculatory perfusion (sidestream dark field imaging), skin perfusion, and oxygenation (laser Doppler flowmetry and reflectance spectroscopy). Results: In responders (subjects with >10 % increase in CO), the HUT to supine change increased CO, SV, and pulse pressure, while heart rate, systemic vascular resistance, and mean arterial pressure decreased. Additionally, microvascular flow index, laser Doppler flow, and microvascular hemoglobin oxygen saturation and concentration also increased. Conclusion: When preload and forward flow increase in association with a decrease in sympathetic activity, microvascular blood flow increases in the skin and in the sublingual area. When preload and forward flow increase with little to no change in sympathetic activity, only sublingual functional capillary density increases. Therefore, our results indicate that sublingual functional capillary density is the best pa

Tissue perfusion and oxygenation to monitor fluid responsiveness in critically ill, septic patients after initial resuscitation: a prospective observational study

Fluid therapy after initial resuscitation in critically ill, septic patients may lead to harmful overloading and should therefore be guided by indicators of an increase in stroke volume (SV), i.e. fluid responsiveness. Our objective was to investigate whether tissue perfusion and oxygenation are able to monitor fluid responsiveness, even after initial resuscitation. Thirty-five critically ill, septic patients underwent infusion of 250 mL of colloids, after initial fluid resuscitation. Prior to and after fluid infusion, SV, cardiac output sublingual microcirculatory perfusion (SDF: sidestream dark field imaging) and skin perfusion and oxygenation (laser Doppler flowmetry and reflectance spectroscopy) were measured. Fluid responsiveness was defined by a ≥5 or 10 % increase in SV upon fluids. In responders to fluids, SDF-derived microcirculatory and skin perfusion and oxygenation increased, but only the increase in cardiac output, mean arterial and pulse pressure, microvascular flow index and relative Hb concentration and oxygen saturation were able to monitor a SV increase. Our proof of principle study demonstrates that non-invasively assessed tissue perfusion and oxygenation is not inferior to invasive hemodynamic measurements in monitoring fluid responsiveness. However skin reflectance spectroscopy may be more helpful than sublingual SDF

High‐Pressure Sintering of Rhombohedral Cr2S3 Using TZM Tools

The influence of sintering parameters on the physical properties and the chemical structure of rhombohedral Cr2S3 (rh‐Cr2S3) is investigated using high pressures and high temperatures. The densification of the powder is performed by applying the high‐pressure field‐assisted sintering technique/spark plasma sintering. Using a titanium–zirconium–molybdenum (TZM) alloy as sintering tool, it is possible to increase the magnitude of the applied pressure to several hundred MPa at temperatures as high as 1223 K. A relative density of up to 99.9% is achieved at a sintering temperature of 1223 K and a pressure of 395 MPa. The presence of phase‐pure rh‐Cr2S3 is proven by X‐ray diffraction analysis and transmission electron microscopy. The Seebeck coefficients of the self‐doped samples change drastically with the sintering temperatures ranging between −650 and −350 μV K−1. The densities and the thermal conductivities of the sintered samples increase with increasing sintering temperatures. The electrical conductivity is largely increased compared with the thermal conductivity potentially due to the current‐assisted high‐pressure sinterin