8,207 research outputs found
Large Magnetoresistance in Co/Ni/Co Ferromagnetic Single Electron Transistors
We report on magnetotransport investigations of nano-scaled ferromagnetic
Co/Ni/Co single electron transistors. As a result of reduced size, the devices
exhibit single electron transistor characteristics at 4.2K. Magnetotransport
measurements carried out at 1.8K reveal tunneling magnetoresistance (TMR)
traces with negative coercive fields, which we interpret in terms of a
switching mechanism driven by the shape anisotropy of the central wire-like Ni
island. A large TMR of about 18% is observed within a finite source-drain bias
regime. The TMR decreases rapidly with increasing bias, which we tentatively
attribute to excitation of magnons in the central island.Comment: 12 pages (including 4 figures). Accepted for publishing on AP
The Boson peak in supercooled water
We perform extensive molecular dynamics simulations of the TIP4P/2005 model
of water to investigate the origin of the Boson peak reported in experiments on
supercooled water in nanoconfined pores, and in hydration water around
proteins. We find that the onset of the Boson peak in supercooled bulk water
coincides with the crossover to a predominantly low-density-like liquid below
the Widom line . The frequency and onset temperature of the Boson peak in
our simulations of bulk water agree well with the results from experiments on
nanoconfined water. Our results suggest that the Boson peak in water is not an
exclusive effect of confinement. We further find that, similar to other
glass-forming liquids, the vibrational modes corresponding to the Boson peak
are spatially extended and are related to transverse phonons found in the
parent crystal, here ice Ih.Comment: 25 pages, 9 figure
Using web GIS to promote stakeholder understanding of scientific results in sustainable urban development: A case study in Bergen, Norway
This paper highlights the importance of improving stakeholder understanding of environmental factors such as air quality and the urban heat island effect to achieve sustainable development goals. While accurate spatial and temporal environmental data are
critical for sustainable solutions, the challenge lies in translating complex environmental
information for non-specialists. To solve this problem, we propose using web GIS storytelling as a powerful tool for communicating and disseminating information about the
environment. This paper aims to show example of implementation of a web-based geographic information system (GIS) on our case study in Bergen, Norway. This platform
āWeb GIS Bergen, air quality and thermal comfortā was created as an open portal. This
document explains the components of the platform, their rationale, and implementation,
which includes important steps. They involve the collection of relevant environmental
data, including modeling results and remote sensing data. Futhermore, the design and
interface of the platform has been carefully considered to provide a user-friendly experience based on interactive maps and storytelling. Combining data visualization and storytelling, the platform promotes a comprehensive understanding of complex
environmental data, including āinvisible killersā such as air pollution and the urban heat
island effect, which significantly affect sustainable development. The strategic integration of this web-based GIS platform in Bergen can serve as an attractive model for other
urban areas looking for practical tools for sustainable development, engaging stakeholders for a healthier and more sustainable urban future
Light-in-flight recording. 5: Theory of slowing down the faster-than-light motion of the light shutter
Light-in-flight recording by holography uses a picosecond pulse for the reference beam, which like a sheet of light intersects the hologram plate and produces a sensitivity area that with a speed faster than light moves over the plate like a light shutter. If, however, the front of the reference pulse by diffraction in a grating is tilted relative to its direction of motion, the velocity of the light shutter can be slowed down resulting in increased recording time. The practical result using a reflection grating was a true recording that corresponded to a time compression of two to one. To minimize distortions of the recorded pulse shape we studied intersections that are identical for apparent (ellipsoidal) and true (spheroidal) wavefronts
Impact of Escherichia coli on Urine Citrate and Urease-Induced Crystallization
Escherichia coli (E. coli) is usually not a urease producer. It is, however, often cultured in urinary phosphate containing calculi including ammonium magnesium phosphate stones. This suggests the possibility that E. coli might be involved in stone forming process. The effect of E. coli on urine citrate and urease-induced crystallization in human urine has been studied in vitro. E. coli was found to strongly reduce urine citrate (after 48 hours). In the E. coli inoculated samples, the urease-induced crystallization was increased. There was a strong correlation, r = 0.8, between the citrate decrease and the increase in calcium precipitation. The results indicate that E. coli and the reduced urine citrate influences urease-induced crystallization in vitro
Severe asphyxia due to delivery-related malpractice in Sweden 1990ā2005
Aim
The objective of the thesis was to describe the most common causes of
substandard care during labour contributing to severe asphyxia or
neonatal death, to study risk factors related to asphyxia associated with
substandard care and to explore the occurrence of substandard care during
labour.
Background
There are about 100 000 infants born every year in Sweden. Most infants
are born healthy after uncomplicated deliveries. However, 20-50 claims
for financial compensation are made annually to the Patients Advisory
Committee (PA C) on suspicion that substandard care during labour has
contributed to severe asphyxia causing cerebral palsy or death. Even if
this group of patients is notably small, asphyxia causes life-long
impairment and immeasurable suffering to the patients and their families.
In addition, the insurance costs are substantial and amount to 25% of all
costs related to substandard care in Sweden. With the exception of this
group of patients, and claims to the Health Services Disciplinary Board,
the frequency of substandard care in relation to childbirth is fairly
unknown.
Material and methods
Inclusion criteria were pregnancies with a gestational length ā„ 33 weeks,
a spontaneous or induced start of labour, a normal CTG at admission for
labour, and Apgar score < 7 at 5 minutes of age (Papers I-IV). 472 case
records of deliveries from 1990-2005, filed at the PAC were scrutinised.
In Paper I and II the deliveries and acts of neonatal resuscitation
procedures are described. In Paper III, maternal characteristics, factors
related to care and infant characteristics for patients receiving
lifelong financial compensation from PAC are compared with all infants
with full Apgar score at 5 minutes of age born after a vaginal start
during the same time period in Sweden (n=1.141 059). In Paper IV
deliveries and risk factors from 313 infants with Apgar score < 7at 5
minutes of age, born in the Stockholm County are compared with 313
infants with full Apgar score at five minutes of age, matched for year of
birth.
Results
One-hundred and seventy-seven infants were considered to have been
severely asphyxiated due to substandard care during labour (Paper I-III).
The most common occurrences of malpractice in conjunction with labour
were neglecting to supervise fetal well-being (98%), neglecting signs of
fetal asphyxia (71%), including incautious use of oxytocin (71%) and
choosing a non-optimal mode of delivery (52%) (Paper I). Resuscitation of
the 177 severely asphyxiated infants was unsatisfactory in 47%. The most
important flaw was the defective compliance with the guidelines
concerning ventilation and prompt paging for skilled personnel in cases
of imminent asphyxia (Paper II). Risk factors associated with asphyxia
included maternal age ā„ 30 years, short maternal stature (< 159 cm),
previous caesarean delivery, insulin-dependent diabetes, induced
deliveries and night deliveries, where the increases in risk were doubled
to a four-fold. In addition, dystocia of labour was associated with a
five-fold increase in risk, which was further increased if epidural
anaesthesia or opioids were used. Small- and large-for-gestational age
infants, post-term (> 42 weeks) births, twins and breech deliveries had a
three to eight-fold increase in risk of asphyxia when there was
substandard care during labour (Paper III). Two thirds of infants born in
the Stockholm region 2004-2006, with Apgar score < 7 at 5 minutes but
also one third of the healthy controls were subjected to some kind of
substandard care during labour (Paper IV). The main causes of substandard
care during labour were related to misinterpretation of CTG, not acting
timely on abnormal CTG, and incautious use of oxytocin. The risk of
asphyxia increased with duration of abnormal CTG and was increased
fifteen-fold when this was abnormal for ā„ 90 minutes. Oxytocin was
provided without sign of inertia in 20% of cases and controls and the
risk of asphyxia was increased more than fivefold in cases of
tachysystole. Infants born after a spontaneous vaginal delivery with
abnormal CTG for more than 45 minutes had a more than sevenfold risk of
low Apgar score. In instrumental deliveries that were considered complex,
there was a more than seventeen-fold risk of an Apgar score < 7 at 5
minutes of age. Assuming that substandard care is causative for low Apgar
score, we estimate that 42% of the cases could be prevented by avoiding
substandard care (Paper IV).
Conclusion
It is possible to improve patient safety during labour by applying
educational efforts on fetal surveillance and increasing awareness of
risk factors associated with asphyxia. The main causes of substandard
care during labour are related to misinterpretation of CTG, not acting
timely on abnormal CTG, misinterpretation of guidelines and misuse of
oxytocin. Low Apgar score at 5 minutes of age can substantially, be
prevented by avoiding substandard care
A Method for Producing Site-Specific TEM Specimens from Low Contrast Materials with Nanometer Precision
A method that enables high precision extraction of transmission electron microscope (TEM) specimens in low contrast materials has been developed. The main idea behind this work is to produce high contrast markers on both sides of and close to the area of interest. The markers are filled during the depositing of the protective layer. The marker material can be of either Pt or C depending on which one gives the highest contrast. It is thereby possible to distinguish the location of the area of interest during focused ion beam (FIB) milling and ensure that the TEM sample is extracted precisely at the desired position. This method is generally applicable and enables FIB/scanning electron microscope users to make high quality TEM specimens from small features and low contrast materials without a need for special holders. We explain the details of this method and illustrate its potential by examples from three different types of materials
Three-dimensional visualisation of authentic cases in anatomy learning ā An educational design study
Many studies have investigated the value of three-dimensional (3D) images in learning anatomy. However, there is a lack of knowledge about students learning processes using technology and 3D images. To understand how to facilitate and support the learning of anatomy, there is a need to know more about the student perspectives on how they can use and benefit from 3D images
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