1,099 research outputs found
Do Induced Responses Mediate the Ecological Interactions Between the Specialist Herbivores and Phytopathogens of an Alpine Plant?
Plants are not passive victims of the myriad attackers that rely on them for
nutrition. They have a suite of physical and chemical defences, and are even
able to take advantage of the enemies of their enemies. These strategies are
often only deployed upon attack, so may lead to indirect interactions between
herbivores and phytopathogens. In this study we test for induced responses in
wild populations of an alpine plant (Adenostyles alliariae)
that possesses constitutive chemical defence (pyrrolizidine alkaloids) and
specialist natural enemies (two species of leaf beetle, Oreina
elongata and Oreina cacaliae, and the
phytopathogenic rust Uromyces cacaliae). Plants were induced in
the field using chemical elicitors of the jasmonic acid (JA) and salicylic acid
(SA) pathways and monitored for one month under natural conditions. There was
evidence for induced resistance, with lower probability and later incidence of
attack by beetles in JA-induced plants and of rust infection in SA-induced
plants. We also demonstrate ecological cross-effects, with reduced fungal attack
following JA-induction, and a cost of SA-induction arising from increased beetle
attack. As a result, there is the potential for negative indirect effects of the
beetles on the rust, while in the field the positive indirect effect of the rust
on the beetles appears to be over-ridden by direct effects on plant nutritional
quality. Such interactions resulting from induced susceptibility and resistance
must be considered if we are to exploit plant defences for crop protection using
hormone elicitors or constitutive expression. More generally, the fact that
induced defences are even found in species that possess constitutively-expressed
chemical defence suggests that they may be ubiquitous in higher plants
SWISSspine: a nationwide registry for health technology assessment of lumbar disc prostheses
SWISSspine is a so-called pragmatic trial for assessment of safety and efficiency of total disc arthroplasty (TDA). It follows the new health technology assessment (HTA) principle of "coverage with evidence development”. It is the first mandatory HTA registry of its kind in the history of Swiss orthopaedic surgery. Its goal is the generation of evidence for a decision by the Swiss federal office of health about reimbursement of the concerned technologies and treatments by the basic health insurance of Switzerland. During the time between March 2005 and 2008, 427 interventions with implantation of 497 lumbar total disc arthroplasties have been documented. Data was collected in a prospective, observational multicenter mode. The preliminary timeframe for the registry was 3years and has already been extended. Data collection happens pre- and perioperatively, at the 3months and 1-year follow-up and annually thereafter. Surgery, implant and follow-up case report forms are administered by spinal surgeons. Comorbidity questionnaires, NASS and EQ-5D forms are completed by the patients. Significant and clinically relevant reduction of low back pain VAS (70.3-29.4 points preop to 1-year postop, p<0.0001) leg pain VAS (55.5-19.1 points preop to 1-year postop, p<0.001), improvement of quality of life (EQ-5D, 0.32-0.73 points preop to 1-year postop, p<0.001) and reduction of pain killer consumption was revealed at the 1-year follow-up. There were 14 (3.9%) complications and 7 (2.0%) revisions within the same hospitalization reported for monosegmental TDA; there were 6 (8.6%) complications and 8 (11.4%) revisions for bisegmental surgery. There were 35 patients (9.8%) with complications during followup in monosegmental and 9 (12.9%) in bisegmental surgery and 11 (3.1%) revisions with new hospitalization in monosegmental and 1 (1.4%) in bisegmental surgery. Regression analysis suggested a preoperative VAS "threshold value” of about 44 points for increased likelihood of a minimum clinically relevant back pain improvement. In a short-term perspective, lumbar TDA appears as a relatively safe and efficient procedure concerning pain reduction and improvement of quality of life. Nevertheless, no prediction about the long-term goals of TDA can be made yet. The SWISSspine registry proofs to be an excellent tool for collection of observational data in a nationwide framework whereby advantages and deficits of its design must be considered. It can act as a model for similar projects in other health-care domain
Development of a documentation instrument for the conservative treatment of spinal disorders in the International Spine Registry, Spine Tango
Spine Tango is the first and only International Spine Registry in operation to date. So far, only surgical spinal interventions have been recorded and no comparable structured and comprehensive documentation instrument for conservative treatments of spinal disorders is available. This study reports on the development of a documentation instrument for the conservative treatment of spinal disorders by using the Delphi consensus method. It was conducted with a group of international experts in the field. We also assessed the usability of this new assessment tool with a prospective feasibility study on 97 outpatients and inpatients with low back or neck pain undergoing conservative treatment. The new ‘Spine Tango conservative' questionnaire proved useful and suitable for the documentation of pathologies, conservative treatments and outcomes of patients with low back or neck problems. A follow-up questionnaire seemed less important in the predominantly outpatient setting. In the feasibility study, between 43 and 63% of patients reached the minimal clinically important difference in pain relief and Core Outcome Measures Index at 3months after therapy; 87% of patients with back pain and 85% with neck pain were satisfied with the received treatment. With ‘Spine Tango conservative' a first step has been taken to develop and implement a complementary system for documentation and evaluation of non-surgical spinal interventions and outcomes within the framework of the International Spine Registry. It proved useful and feasible in a first pilot study, but it will take the experience of many more cases and therapists to develop a version similarly mature as the surgical instruments of Spine Tang
Tissue inhibitor of matrix metalloproteinase 1 (TIMP1) controls adipogenesis in obesity in mice and in humans
Aims/hypothesis: Extracellular matrix reorganisation is a crucial step of adipocyte differentiation and is controlled by the matrix metalloproteinase-tissue inhibitor of matrix metalloproteinase (TIMP) enzyme system. We therefore sought to define the role of TIMP1 in adipogenesis and to elucidate whether upregulation of TIMP1 in obesity has direct effects on adipocyte formation. Methods: TIMP1 protein levels and mRNA were measured in lean and obese mice with a focus on levels in adipose tissue. We also analysed the effect of recombinant murine TIMP1 on adipogenesis, adipocyte size and metabolic control in vitro and in vivo. Results: TIMP1 levels were increased in the serum and adipose tissue of obese mouse models. Recombinant murine TIMP1 inhibited adipocyte differentiation in 3T3-L1 as well as in subcutaneous primary pre-adipocytes. Conversely, neutralising TIMP1 with a specific antibody enhanced adipocyte differentiation. In vivo, injection of recombinant TIMP1 in mice challenged with a high-fat diet led to enlarged adipocytes. TIMP1-treated mice developed an impaired metabolic profile with increased circulating NEFA levels, hepatic triacylglycerol accumulation and accelerated insulin resistance. Altered glucose clearance in TIMP1-injected mice was due to changes in adipose tissue glucose uptake, whereas muscle glucose clearance remained unaffected. Conclusions/interpretation: TIMP1 is a negative regulator of adipogenesis. In vivo, TIMP1 leads to enlarged adipocytes in the state of overnutrition. This might contribute to the detrimental metabolic consequences seen in TIMP1-injected mice, such as systemic fatty acid overload, hepatic lipid accumulation and insulin resistanc
Low Temperature Magnetic Properties of the Double Exchange Model
We study the {\it ferromagnetic} (FM) Kondo lattice model in the strong
coupling limit (double exchange (DE) model). The DE mechanism proposed by Zener
to explain ferromagnetism has unexpected properties when there is more than one
itinerant electron. We find that, in general, the many-body ground state of the
DE model is {\it not} globally FM ordered (except for special filled-shell
cases). Also, the low energy excitations of this model are distinct from spin
wave excitations in usual Heisenberg ferromagnets, which will result in unusual
dynamic magnetic properties.Comment: 5 pages, RevTeX, 5 Postscript figures include
Great Sumatra Earthquake Registers on Electrostatic Sensor
Strong electrical signals that correspond to
the Mw = 9.3 earthquake of 26 December 2004,
which occurred at 0058:50.7 UTC
off the west coast of northern Sumatra, Indonesia,
were recorded by an electrostatic sensor
(a device that detects short-term variations in
Earth’s electrostatic fi eld) at a seismic station
in Italy, which had been installed to study the
infl uence of local earthquakes on a new landslide
monitoring system.
Electrical signals arrived at the station practically
instantaneously and were detected up
to several hours before the onset of the Sumatra
earthquake (Figure 1) as well as before
local quakes. The corresponding seismic signals
(p-waves) arrived 740 seconds after the
start of the earthquake. Because the electrical
signals travel at the speed of light, electrical
monitoring for the global detection of very
strong earthquakes could be an important
tool in signifi cantly increasing the hazard
alert window
Evaluation of laboratory and on-farm tests to estimate colostrum quality for dairy cows
The objectives of this study were to evaluate different analytical methods to determine colostrum quality in dairy cattle, including one laboratory-based method (ELISA) and 4 on-farm tests. We hypothesized that the colostral IgG concentration using different analytical methods, such as ELISA (mg/mL), digital Brix refractometer (% Brix), colostrometer (specific gravity and mg/mL), an outflow funnel (seconds), and a lateral flow assay (mg/mL), were highly correlated with the reference method, radial immunodiffusion (RID; mg/mL) and would generate comparable results. Colostrum samples were collected from 209 Holstein Friesian cows on 2 commercial dairy farms in Germany. Colostrum weight and colostrum temperature were measured. Test characteristics, such as optimum thresholds, sensitivity, specificity, and area under the curve (AUC) were determined using a receiver operating characteristic curve analyses for each test. Out of 209 colostrum samples assessed by RID, 186 (89%) samples had high quality (≥50 mg IgG/mL), while 23 colostrum samples (11%) showed poor quality with IgG concentrations less than 50 mg/mL. The mean IgG concentration (±SD) was 101.3 ± 45.9 mg/mL and the range was 6.0 to 244.3 mg/mL. The Pearson correlation coefficient (r) between RID and ELISA was r = 0.78. In comparison to RID, Pearson correlation coefficients for the on-farm tests were: r = 0.79 (digital Brix refractometry), r = 0.58 (colostrometer: specific gravity), r = 0.61 (colostrometer: temperature corrected), r = 0.26 (outflow funnel) and r = 0.43 (lateral flow assay), respectively. The optimal threshold to identify high-quality colostrum using ELISA was 50.8 mg/mL with sensitivity 91.3%, specificity 92.3%, and AUC of 0.94. For the on-farm tests sensitivity ranged from 95.7% (Brix refractometry) to 60.9% (lateral flow assay). Specificity ranged from 88.6% (lateral flow assay) to 75.9% (colostrometer: temperature corrected). The AUC ranged from 0.93 (Brix refractometry) to 0.73 (outflow funnel). Based on the AUC, ELISA (0.94) and Brix refractometry (0.93) can be considered highly accurate. In conclusion, the ELISA is accurate to assess colostrum quality. Regarding the on-farm tests only the digital Brix refractometer and the colostrometer were adequate to determine colostrum quality
The Quark-Mass Dependence of T_C in QCD: Working up from m=0 or down from m=infinity ?
We analyze the dependence of the QCD transition temperature on the quark (or
pion) mass. We find that a linear sigma model, which links the transition to
chiral symmetry restoration, predicts a much stronger dependence of T_c on m_pi
than seen in present lattice data for m_pi >~ 0.4 GeV. On the other hand,
working down from m_pi=infinity, an effective Lagrangian for the Polyakov loop
requires only small explicit symmetry breaking, b_1 ~ exp(-m_pi), to describe
T_c(m_pi) in the above mass range. Physically, this is a consequence of the
flat potential (large correlation length) for the Polyakov loop in the
three-color pure gauge theory at T_c. We quantitatively estimate the end point
of the line of first order deconfining phase transitions: m_pi = 1.8 GeV and Tc
= 240 MeV for three flavors and three colors.Comment: 9 pages, 3 figures; v2: renormalization of vacuum fluctuations in the
linear sigma model and some references added; final version to appear in PR
Persistent Current in the Ferromagnetic Kondo Lattice Model
In this paper, we study the zero temperature persistent current in a
ferromagnetic Kondo lattice model in the strong coupling limit. In this model,
there are spontaneous spin textures at some values of the external magnetic
flux. These spin textures contribute a geometric flux, which can induce an
additional spontaneous persistent current. Since this spin texture changes with
the external magnetic flux, we find that there is an anomalous persistent
current in some region of magnetic flux: near Phi/Phi_0=0 for an even number of
electrons and Phi/Phi_0=1/2 for an odd number of electrons.Comment: 6 RevTeX pages, 10 figures include
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