1,922 research outputs found
Finsler pp-waves
In this work we present a Finslerian version of the well-known pp-waves,
which generalizes the very special relativity (VSR) line element. Our Finsler
pp-waves are an exact solution of Finslerian Einstein's equations in vacuum.Comment: 10 pages, minor corrections, references adde
Advances in electrical high current connections for electrical propulsion systems
Many countries strongly support electric propulsion for various fields of transportation, be
it people or goods on land, at sea or in the air. Although electric drive systems appear much
simpler than (internal) combustion systems, they exhibit their own challenging development
tasks. This becomes obvious when an ever-increasing efficiency, performance or production
rate is required, just to name a few.
The new challenges can be tackled with the help of new electromagnetic manufacturing
processes. High speed processes with their well-known unique capabilities offer promising
approaches. However, development is required in order to deliver the required performance.
High-speed forming with electromagnetic tools allows the production of sharp-edged battery
housings. For body panels, sharp edges are mainly a design feature. For batteries, however,
sharp edges allow for an almost ideally rectangular housing, enabling a higher energy
density. Increases in the range of up to 10 % are achievable.
When it comes to packaging, the liquid cooling and heating of battery packs is of equally
large importance. The channels for the medium must not consume too much space. The
integration of channels inside the aluminium or steel frame of the battery pack is a promising
approach. Due to the high welding speeds of up to 500 mm per second at optimum conditions
and at the same time the ability to weld aluminium to aluminium or even steel without any
loss in strength, electromagnetic pulse welding offers a promising solution.
The conduction of high electrical currents with for example the strong demand to save
weight and thus use as little material as possible also requires new processes.
Electromagnetic pulse welding of aluminium to aluminium and aluminium to copper is well
known, investigated and already used in mass production. However, this is suitable for bus
bars only. The connection of terminals to cables is mostly done by crimping. Using a pulsed
force for crimping improves the compaction and thus the resistance of the joint, especially
of cables with large cross sections. This allows for smaller connectors and reduced cable
cross sections
Carbon radio recombination lines from gigahertz to megahertz frequencies towards Orion A
Context. The combined use of carbon radio recombination lines (CRRLs) and the
158 m-[CII] line is a powerful tool for the study of the energetics and
physical conditions (e.g., temperature and density) of photodissociation
regions (PDRs). However, there are few observational studies that exploit this
synergy. Aims. Here we explore the relation between CRRLs and the 158
m-[CII] line in light of new observations and models. Methods. We present
new and existing observations of CRRLs in the frequency range 0.15--230 GHz
with ALMA, VLA, the GBT, Effelsberg 100m, and LOFAR towards Orion~A (M42). We
complement these observations with SOFIA observations of the 158 m-[CII]
line. We studied two PDRs: the foreground atomic gas, known as the Veil, and
the dense PDR between the HII region and the background molecular cloud.
Results. In the Veil we are able to determine the gas temperature and electron
density, which we use to measure the ionization parameter and the photoelectric
heating efficiency. In the dense PDR, we are able to identify a layered PDR
structure at the surface of the molecular cloud to the south of the Trapezium
cluster. There we find that the radio lines trace the colder portion of the
ionized carbon layer, the C/C/CO interface. By modeling the emission of
the ~m-[CII] line and CRRLs as arising from a PDR we derive a thermal
pressure K cm and a radiation field
close to the Trapezium. Conclusions. This work provides
additional observational support for the use of CRRLs and the 158 m-[CII]
line as complementary tools to study dense and diffuse PDRs, and highlights the
usefulness of CRRLs as probes of the C/C/CO interface.Comment: 18 pages, 16 figures, accepted for publication in A&
What is the clinical relevance of different lung compartments?
The lung consists of at least seven compartments with relevance to immune reactions. Compartment 1 - the bronchoalveolar lavage (BAL), which represents the cells of the bronchoalveolar space: From a diagnostic point of view the bronchoalveolar space is the most important because it is easily accessible in laboratory animals, as well as in patients, using BAL. Although this technique has been used for several decades it is still unclear to what extent the BAL represents changes in other lung compartments. Compartment 2 - bronchus-associated lymphoid tissue (BALT): In the healthy, BALT can be found only in childhood. The role of BALT in the development of the mucosal immunity of the pulmonary surfaces has not yet been resolved. However, it might be an important tool for inhalative vaccination strategies. Compartment 3 - conducting airway mucosa: A third compartment is the bronchial epithelium and the submucosa, which both contain a distinct pool of leukocytes (e.g. intraepithelial lymphocytes, IEL). This again is also accessible via bronchoscopy. Compartment 4 - draining lymph nodes/Compartment 5 - lung parenchyma: Transbronchial biopsies are more difficult to perform but provide access to two additional compartments - lymph nodes with the draining lymphatics and lung parenchyma, which roughly means "interstitial" lung tissue. Compartment 6 - the intravascular leukocyte pool: The intravascular compartment lies between the systemic circulation and inflamed lung compartments. Compartment 7 - periarterial space: Finally, there is a unique, lung-specific space around the pulmonary arteries which contains blood and lymph capillaries. There are indications that this "periarterial space" may be involved in the pulmonary host defense
Suitable Design for Electromagnetic Pulse Processes
Basic conventional production processes, such as arc welding or forming, are more or less
thoroughly investigated, reliable process guidelines have been developed and trained
engineers are available. This allows them to be put into use usually fast, thus facilitating a
wide application.
The usage of electromagnetic pulse processes, on the contrary, still lacks a broad
propagation. Despite having a history reaching back several decades, these processes are
mostly limited to niche applications. Admittedly, theoretical considerations have been made
and various experiments have been carried out. However, when a given joining or forming
task needs to be realized with electro-magnetic force, a huge invest is necessary even before
the first part is made. This involves the design of the machine, especially of the tool coil, as
well as the design of the workpieces to be processed.
In industrial environmentsthis challenge is tackled step by step: After the theoretical product
concept in close collaboration with the customer, numerical and experimental trials are
carried out. In many cases, iterations are necessary and both geometry and process are
optimized. The experimental trials can be conducted with universal sheet welding tool coils
or tube compression tool coils with custom field shapers. This procedure allows keeping the
prototyping costs low, but at the same time provides valid information on the feasibility in
general, the requirements to the workpieces, the design of the tool coil and the properties of
the pulse generator. Subsequently, the tool coil is designed and manufactured according to
the prior findings. The pulse generator as modular component is assembled and adapted to
the customer’s requirements.
The iterative product and process design is the most important phase of the whole procedure,
which is in accordance with good project management. It significantly lowers the risk of an
expensive project cancellation during the late steps
Associations between anxiety, body mass index, and sex hormones in women
Background: Several studies have shown a positive association between anxiety and obesity, particularly in women. We aimed to study whether sex hormone alterations related to obesity might play a role in this association. Patients and methods: Data for this study were obtained from a population-based cohort study (the LIFE-Adult-Study). A total of 3,124 adult women (970 premenopausal and 2,154 postmenopausal) were included into the analyses. The anxiety symptomatology was assessed using the GAD-7 questionnaire (cut-off ≥ 10 points). Sex hormones were measured from fasting serum samples. Results: We did not find significant differences in anxiety prevalence in premenopausal obese women compared with normal-weight controls (4.8% vs. 5.5%). Both obesity and anxiety symptomatology were separately associated with the same sex hormone alteration in premenopausal women: higher total testosterone level (0.97 ± 0.50 in obese vs. 0.86 ± 0.49 nmol/L in normal-weight women, p = 0.026 and 1.04 ± 0.59 in women with vs. 0.88 ± 0.49 nmol/L in women without anxiety symptomatology, p = 0.023). However, women with anxiety symptomatology had non-significantly higher estradiol levels than women without anxiety symptomatology (548.0 ± 507.6 vs. 426.2 ± 474.0 pmol/L), whereas obesity was associated with lower estradiol levels compared with those in normal-weight group (332.7 ± 386.5 vs. 470.8 ± 616.0 pmol/L). Women with anxiety symptomatology had also significantly higher testosterone and estradiol composition (p = 0.006). No associations of sex hormone levels and BMI with anxiety symptomatology in postmenopausal women were found. Conclusions: Although both obesity and anxiety symptomatology were separately associated with higher testosterone level, there was an opposite impact of anxiety and obesity on estradiol levels in premenopausal women. We did not find an evidence that the sex hormone alterations related to obesity are playing a significant role in anxiety symptomatology in premenopausal women. This could be the explanation why we did not find an association between obesity and anxiety. In postmenopausal women, other mechanisms seem to work than in the premenopausal group
Heterogeneity within AML with CEBPA mutations; only CEBPA double mutations, but not single CEBPA mutations are associated with favourable prognosis
CCAAT/enhancer binding protein alpha (CEBPA) mutations in AML are associated with favourable prognosis and are divided into N- and C-terminal mutations. The majority of AML patients have both types of mutations. We assessed the prognostic significance of single (n=7) and double (n=12) CEBPA mutations among 224 AML patients. Double CEBPA mutations conferred a decisively favourable overall (P=0.006) and disease-free survival (P=0.013). However, clinical outcome of patients with single CEBPA mutations was not different from CEBPA wild-type patients. In a multivariable analysis, only double – but not single – CEBPA mutations were identified as independent prognostic factors. These findings indicate heterogeneity within AML patients with CEBPA mutations
Improvement of quality of life in patients with concomitant allergic asthma and atopic dermatitis: one year follow-up of omalizumab therapy
<p>Abstract</p> <p>Objective</p> <p>Anti IgE treatment with omalizumab is efficacious in the treatment of patients suffering from allergic asthma, improving asthma control and improving quality of life. Furthermore, this approach could be beneficial for patients with concomitant atopic dermatitis. We assessed quality of life and asthma control in atopic patients with allergic asthma and concomitant atopic dermatitis versus those with asthma and without atopic dermatitis treated with omalizumab.</p> <p>Methods</p> <p>A total of 22 patients with severe allergic asthma were treated with omalizumab for 12 months. 13 patients with allergic asthma without concomitant atopic dermatitis (IgE 212 ± 224 IU/ml) and 9 patients with concomitant allergic asthma and atopic dermatitis (IgE 3,528 ± 2,723 IU/ml) were included. Asthma-related quality of life (AQLQ), atopic dermatitis related quality of life (DLQI), and asthma-related treatment were compared between both groups at baseline and after initiating omalizumab treatment.</p> <p>Results</p> <p>DLQI was significantly in favor of omalizumab after 2 months in the atopic dermatitis/asthma group (P = 0.01); AQLQ was improved after 6 months in the asthma group (P = 0.01), while no change was seen in AQLQ in the atopic dermatitis/asthma group (P = 0.12). Omalizumab controlled oral corticosteroid use more effective (P < 0.01) in patients with asthma and atopic dermatitis (in 9/9 cases) compared to patients with asthma alone (9/13). Baseline IgE as well as other factors do not predict response to omalizumab.</p> <p>Conclusions</p> <p>Omalizumab is effective in improving atopic dermatitis-related quality of life scores and modulates oral corticosteroid use in patients with concomitant asthma and atopic dermatitis in a positive fashion.</p
Tree Species Diversity Increases with Conspecific Negative Density Dependence Across an Elevation Gradient
Elevational and latitudinal gradients in species diversity may be mediated by biotic interactions that cause density-dependent effects of conspecifics on survival or growth to differ from effects of heterospecifics (i.e. conspecific density dependence), but limited evidence exists to support this. We tested the hypothesis that conspecific density dependence varies with elevation using over 40 years of data on tree survival and growth from 23 old-growth temperate forest stands across a 1,000-m elevation gradient. We found that conspecific-density-dependent effects on survival of small-to-intermediate-sized focal trees were negative in lower elevation, higher diversity forest stands typically characterised by warmer temperatures and greater relative humidity. Conspecific-density-dependent effects on survival were less negative in higher elevation stands and ridges than in lower elevation stands and valley bottoms for small-to-intermediate-sized trees, but were neutral for larger trees across elevations. Conspecific-density-dependent effects on growth were negative across all tree size classes and elevations. These findings reveal fundamental differences in biotic interactions that may contribute to relationships between species diversity, elevation and climate
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