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Force, acceleration and velocity during trampoline jumps - A challenging assignment

Bouncing on a trampoline lets the jumper experience the interplay between weightlessness and large forces on the body, as the motion changes between free fall and large acceleration in contact with the trampoline bed. In this work, several groups of students were asked to draw graphs of elevation, velocity and acceleration as a function of time, for two full jumps of the 2012 Olympic gold medal tr

Aquaporin protein-protein interactions

Aquaporins are tetrameric membrane-bound channels that facilitate transport of water and other small solutes across cell membranes. In eukaryotes, they are frequently regulated by gating or trafficking, allowing for the cell to control membrane permeability in a specific manner. Protein-protein interactions play crucial roles in both regulatory processes and also mediate alternative functions such

Free fall and the equivalence principle revisited

Free fall is commonly discussed as an example of the equivalence principle, in the context of a homogeneous gravitational field, which is a reasonable approximation for small test masses falling moderate distances. Newton's law of gravity provides a generalisation to larger distances, and also brings in an inhomogeneity in the gravitational field. In addition, Newton's third law of action and reac

Toke och andra aristokratiska kyrkbyggare i det medeltida Lund

Aristokratiska gårdsanläggningar med residensbyggnad och kyrka var vanligt förekommande på den medeltida landsbygden. Företeelsen tycks ha existerat också i urbana miljöer. De icke-regala lundensiska träkyrkorna kan ses som privatkyrkor indikerande på aristokratiska stadsgårdar. Dessa ersattes senare med stenkyrkor vilka via patronatskap fortsatt var knutna till frälsets urbana gårdar, en rumslig

Renovation of Swedish single-family houses to passive house standard : Sensitivity analysis

A third of Sweden’s two million single-family houses were built in the period 1961-1980, and many of them are in need of renovation. Energy use in these houses is high, and they are fairly homogeneous in technical terms. A previous study of four reference houses showed that final energy use could be reduced in theory by approximately 65-75 % after renovation, by implementing conventional passive h

Renovation of Swedish single-family houses from the 1960s and 1970s to net-zero energy buildings : Case study

This paper evaluates whether a net-zero energy building (NZEB) can be attained by implementing on-site renewable electricity production when renovating to Passive House level. The assessment is based on the Swedish single-family housing stock constructed between 1961 and 1980, using two case study houses and three locations. Specific conditions of the houses, such as the type of heat generation an

Time contracts and temporal precision declines when the mind wanders

Our perception of time varies considerably from moment to moment, but how this variability relates to endogenous fluctuations in attentional states has been neglected. Here, we tested the hypothesis that perceptual decoupling during spontaneous mind wandering episodes distorts interval timing. In two studies with different visual subsecond interval timing paradigms, participants judged their atten

One hundred years of Quaternary pollen analysis 1916–2016

We review the history of Quaternary pollen analysis from 1916 to the present-day, with particular emphasis on methodological and conceptual developments and on the early pioneers of the subject. The history is divided into three phases—the pioneer phase 1916–1950, the building phase 1951–1973, and the mature phase 1974–present-day. We also explore relevant studies prior to Lennart von Post’s semin

Short-term carbon input increases microbial nitrogen demand, but not microbial nitrogen mining, in a set of boreal forest soils

Rising carbon dioxide (CO2) concentrations and temperatures are expected to stimulate plant productivity and ecosystem C sequestration, but these effects require a concurrent increase in N availability for plants. Plants might indirectly promote N availability as they release organic C into the soil (e.g., by root exudation) that can increase microbial soil organic matter (SOM) decomposition (“pri

Local and trans-Atlantic chemostratigraphic significance of new δ13Ccarb data from the Sandbian and Katian Stages (Middle–Upper Ordovician) of the Oslo region, Norway

Late Sandbian to early Katian δ13Ccarb chemostratigraphy has in Norway been described in only two previous reports that dealt with two geographically rather widely separated areas, namely the Oslo-Asker district and the Nes-Hamar district. No data have been available from the Ordovician outcrop areas between these districts that could help clarify the partly unclear regional stratigraphic relation

From discovery to justification : Outline of an ideal research program in empirical psychology

The gold standard for an empirical science is the replicability of its research results. But the estimated average replicability rate of key-effects that top-tier psychology journals report falls between 36 and 39% (objective vs. subjective rate; Open Science Collaboration, 2015). So the standard mode of applying null-hypothesis significance testing (NHST) fails to adequately separate stable from

The Harmonized Parabolic Synthesis Methodology for Hardware Efficient Function Generation with Full Error Control

The Harmonized Parabolic Synthesis methodology is a further development of the Parabolic Synthesis methodology for approximation of unary functions such as trigonometric functions, logarithms and the square root with moderate accuracy for ASIC implementation. These functions are extensively used in computer graphics, communication systems and many other application areas. For these high-speed appl

Abnormalities at different levels of the hypothalamic-pituitary-adrenocortical axis early after stroke

BACKGROUND AND PURPOSE: Hypercortisolism is common in stroke patients. The aim of this study was to investigate possible disturbances at different sites within the hypothalamic-pituitary-adrenal axis. We also studied possible associations between hypercortisolism and clinical manifestations of brain dysfunction.METHODS: Patients with an acute ischemic stroke (n = 16; mean +/- SD age, 71 +/- 11 yea

Glycerol as a marker for post-traumatic membrane phospholipid degradation in rat brain

Degradation of membrane phospholipids (PLs) is a well known phenomenon in acute brain injuries and is thought to underlie the disturbance of vital cellular membrane functions. In the present study glycerol, an end product of PL degradation, was examined in brain interstitial fluid as a marker of PL breakdown following experimental traumatic brain injury (TBI) using microdialysis. TBI was induced i

Hypoxanthine, uric acid and allantoin as indicators of in vivo free radical reactions. Description of a HPLC method and human brain microdialysis data

A practical one-step high performance liquid chromatography (HPLC) method was developed for the simultaneous determination of hypoxanthine, uric acid and allantoin in small (4 microL) microdialysis samples. The rationale for this work was the current interest in hypoxanthine as a marker for energy perturbation in hypoxia/ ischemia, in uric acid as an endogenous antioxidant, and in allantoin as a m

Fibroblasts potentiate melanoma cells in vitro invasiveness induced by UV-irradiated keratinocytes

Melanoma represents a malignant disease with steadily increasing incidence. UV-irradiation is a recognized key factor in melanoma initiation. Therefore, the efficient prevention of UV tissue damage bears a critical potential for melanoma prevention. In this study, we tested the effect of UV irradiation of normal keratinocytes and their consequent interaction with normal and cancer-associated fibro

Intracerebral microdialysis in neurointensive care : the use of urea as an endogenous reference compound

OBJECT: When evaluating the results of intracerebral microdialysis, the in vivo performance of the microdialysis probe must be considered, because this determines the fraction of the interstitial concentration obtained in the microdialysis samples. The in vivo performance is dependent on several factors, for example, the interstitial compartment's diffusion characteristics, which may vary during t

Active listing and more consultations in primary care are associated with reduced hospitalisation in a Swedish population

Background: Healthcare systems are complex networks where relationships affect outcomes. The importance of primary care increases while health care acknowledges multimorbidity, the impact of combinations of different diseases in one person. Active listing and consultations in primary care could be used as proxies of the relationships between patients and primary care. Our objective was to study ho

Epidemiology of primary systemic vasculitis in children : a population-based study from southern Sweden

Objectives: To estimate the annual incidence rate of paediatric primary systemic vasculitis (PSV) in a defined geographical area in southern Sweden. Methods: Potential cases of PSV [IgA vasculitis (IgAV, Henoch–Schönlein purpura), Kawasaki disease (KD), granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), eosinophilic granulomatosis with polyangiitis (EGPA), polyarteritis nodosa

Paradoxical increase in neuronal DNA fragmentation after neuroprotective free radical scavenger treatment in experimental traumatic brain injury

The mechanisms and role of nerve cell death after traumatic brain injury (TBI) are not fully understood. The authors investigated the effect of pretreatment with the oxygen free radical spin trap alpha-phenyl-N-tert-butyl-nitrone (PBN) on the number of neurons undergoing apoptosis after TBI in rats. Apoptotic cells were identified by the TUNEL method combined with the nuclear stain, Hoechst 33258,