1,331 research outputs found
Determinants of Economic Growth in Organic Farming: The Case of Bavaria and Baden-Wuerttemberg
The organic sector in Germany has experienced a substantial growth since the beginning of the 1990s until today. During this process of expansion, most organic farms have grown in terms of factor endowment, while others have disappeared or reconverted to conventional agriculture. This paper investigates the potential determinants of farms growth in the organic sector. This paper models potential factors that might have an impact on the economic growth of 332 organic farms in Bavaria and Baden-Wuerttemberg. The econometric model was developed based on ‘Gibrat’s Law’, using a fixed effect method (FE). The results suggest that direct marketing and livestock intensity significantly influence farm growth. In addition, less efficient farms grew faster than more efficient ones. This outcome can be explained by the economic pressure on inefficient firms for adaptation during the growth and survival process.farm-growth, Gibrat’s law, technical efficiency, direct marketing, Farm Management,
Effects of RAF inhibitors on PI3K/AKT signalling depend on mutational status of the RAS/RAF signalling axis
Targeted therapies within the RAS/RAF/MEK/ERK signalling axis become increasingly popular, yet cross-talk and feedbacks in the signalling network lead to unexpected effects. Here we look systematically into how inhibiting RAF and MEK with clinically relevant inhibitors result in changes in PI3K/AKT activation. We measure the signalling response using a bead-based ELISA, and use a panel of three cell lines, and isogenic cell lines that express mutant forms of the oncogenes KRAS and BRAF to interrogate the effects of the MEK and RAF inhibitors on signalling. We find that treatment with the RAF inhibitors have opposing effects on AKT phosphorylation depending on the mutational status of two important oncogenes, KRAS and BRAF. If these two genes are in wildtype configuration, RAF inhibitors reduce AKT phosphorylation. In contrast, if BRAF or KRAS are mutant, RAF inhibitors will leave AKT phosphorylation unaffected or lead to an increase of AKT phosphorylation. Down-regulation of phospho-AKT by RAF inhibitors also extends to downstream transcription factors, and correlates with apoptosis induction. Our results show that oncogenes rewire signalling such that targeted therapies can have opposing effects on parallel pathways, which depend on the mutational status of the cell
The Hilbert basis method for D-flat directions and the superpotential
We discuss, using the Hilbert basis method, how to efficiently construct a
complete basis for D-flat directions in supersymmetric Abelian and non-Abelian
gauge theories. We extend the method to discrete (R and non-R) symmetries. This
facilitates the construction of a basis of all superpotential terms in a theory
with given symmetries.Comment: 11 pages; a related mathematica code can be found at
http://einrichtungen.ph.tum.de/T30e/codes/NonAbelianHilbert
Gab2 deficiency prevents Flt3-ITD driven acute myeloid leukemia in vivo
Internal tandem duplications (ITD) of the FMS-like tyrosine kinase 3 (FLT3) predict poor prognosis in acute myeloid leukemia (AML) and often co-exist with inactivating DNMT3A mutations. In vitro studies implicated Grb2-associated binder 2 (GAB2) as FLT3-ITD effector. Utilizing a Flt3-ITD knock-in, Dnmt3a haploinsufficient mouse model, we demonstrate that Gab2 is essential for the development of Flt3-ITD driven AML in vivo, as Gab2 deficient mice displayed prolonged survival, presented with attenuated liver and spleen pathology and reduced blast counts. Furthermore, leukemic bone marrow from Gab2 deficient mice exhibited reduced colony-forming unit capacity and increased FLT3 inhibitor sensitivity. Using transcriptomics, we identify the genes encoding for Axl and the Ret co-receptor Gfra2 as targets of the Flt3-ITD/Gab2/Stat5 axis. We propose a pathomechanism in which Gab2 increases signaling of these receptors by inducing their expression and by serving as downstream effector. Thereby, Gab2 promotes AML aggressiveness and drug resistance as it incorporates these receptor tyrosine kinases into the Flt3-ITD signaling network. Consequently, our data identify GAB2 as a promising biomarker and therapeutic target in human AML
Madagascar corals reveal a multidecadal signature of rainfall and river runoff since 1708
Pacific Ocean sea surface temperatures (SST) influence rainfall variability on multidecadal and interdecadal timescales in concert with the Pacific Decadal Oscillation (PDO) and Interdecadal Pacific Oscillation (IPO). Rainfall variations in locations such as Australia and North America are therefore linked to phase changes in the PDO. Furthermore, studies have suggested teleconnections exist between the western Indian Ocean and Pacific Decadal Variability (PDV), similar to those observed on interannual timescales related to the El Niño Southern Oscillation (ENSO). However, as instrumental records of rainfall are too short and sparse to confidently assess multidecadal climatic teleconnections, here we present four coral climate archives from Madagascar spanning up to the past 300 yr (1708–2008) to assess such decadal variability. Using spectral luminescence scanning to reconstruct past changes in river runoff, we identify significant multidecadal and interdecadal frequencies in the coral records, which before 1900 are coherent with Asian-based PDO reconstructions. This multidecadal relationship with the Asian-based PDO reconstructions points to an unidentified teleconnection mechanism that affects Madagascar rainfall/runoff, most likely triggered by multidecadal changes in North Pacific SST, influencing the Asian Monsoon circulation. In the 20th century we decouple human deforestation effects from rainfall-induced soil erosion by pairing luminescence with coral geochemistry. Positive PDO phases are associated with increased Indian Ocean temperatures and runoff/rainfall in eastern Madagascar, while precipitation in southern Africa and eastern Australia declines. Consequently, the negative PDO phase that started in 1998 may contribute to reduced rainfall over eastern Madagascar and increased precipitation in southern Africa and eastern Australia. We conclude that multidecadal rainfall variability in Madagascar and the western Indian Ocean needs to be taken into account when considering water resource management under a future warming climate
Stress urinary incontinence after hysterectomy : a 10-year national follow-up study
Purpose Hysterectomy has been associated with increased risk for developing stress urinary incontinence (SUI) and having a SUI operation. We examined the long-term rate of SUI operations after hysterectomy and associated risk factors. Methods We followed up 5000 women without prior urinary incontinence (UI) who had a hysterectomy in a prospective FINHYST 2006 cohort study until the end of 2016 through a national health register. The main outcome was SUI operations, and secondary outcomes were outpatient visits for UI, and their association of preoperative patient and operation factors. Results During the median follow-up time of 10.6 years (IQR 10.3-10.8), 111 (2.2%) women had a SUI operation and 241 (4.8%) had an outpatient visit for UI. The SUI operation rate was higher after vaginal hysterectomy and laparoscopic hysterectomy (n = 71 and 28, 3.3% and 1.8%, respectively) compared to abdominal hysterectomy (n = 11, 0.8%). In a multivariate risk analysis by Cox regression, the association with vaginal hysterectomy and SUI operation remained significant when adjusted for vaginal deliveries, preceding pelvic organ prolapse (POP), uterus size, age and BMI (HR 2.4, 95% CI 1.1-5.3). Preceding POP, three or more deliveries and laparoscopic hysterectomy were significantly associated with UI visits but not with SUI operations. Conclusion After hysterectomy, 2.2% of women underwent operative treatment for SUI. The number of SUI operations was more than double after vaginal hysterectomy compared to abdominal hysterectomy, but preceding POP explained this added risk partially. Preceding POP and three or more vaginal deliveries were independently associated with UI visits after hysterectomy.Peer reviewe
Development of Methodologies to Reduce the DCAD of Hays for Transition Dairy Cows
Hypocalcemia (clinical and subclinical) create a major economic loss in early postpartum dairy cows. Ration formulation for dairy cows just prior to parturition must control the diet cation-anion difference (DCAD) if hypocalcemia and milk fever are to be avoided. The purpose of this research was to evaluate the use of specific fertilizer regimes for forages and evaluate their impact on mineral and DCAD levels in hays, as well as forage yields. The experimental design involved four different species of hay (alfalfa, bromegrass, orchardgrass, and reed canarygrass) fertilized with either CaCl2 or K2CO3 (designated K2O) alone or a combination (designated KCl) of both.
In the plots not receiving K fertilization (Control and CaCl2) the K content of the plants regardless of species was lower relative to those receiving K (K2O and KCl). With regards to plant Cl content, the plots fertilized with CaCl2 alone or in combination with K2O resulted in substantial and at least a 2 fold elevations in tissue chloride in all the hays tested. DCAD was also significantly reduced with CaCl2 treatment alone and was reduced 50-75% in the Orchardgrass, Reed Canarygrass and Orchardgrass hays. The combination of K2O and CaCl2 resulted in an attenuation of this effect. CaCl2 treatment alone had no detrimental effect on yield when compared to Control plots. However, those plots fertilized with K (with or without Cl) had higher numerical yields than those not receiving K.
These data suggest that withholding K fertilization in combination with Cl fertilization may be an effective means of increasing the Cl and ultimately decreasing the DCAD content of several species of hay without sacrificing yield. We will continue to monitor the effects of K and Cl fertilization on plant parameters during the FY05 and FY06 growing seasons. The effect of Cl fertilization on hay quality and palatability is currently under investigation
Development of Methodologies to Reduce the DCAD of Hay Forages for Transition Dairy Cows
Ration formulation for dairy cows just prior to parturition must control the dietary cation-anion difference (DCAD) if hypocalcemia and milk fever are to be avoided. One key to reducing hypocalcemia is to avoid incorporation of high-K forages into the ration. The excessive K content of these forages can cause metabolic alkalosis in the cow and subsequently hypocalcemia and milk fever. Alfalfa and other cool-season grasses are often used in dairy rations. Reducing K content of forages can be achieved by restricting K fertilization so that soils do not support luxury consumption. Since K is the major cation contributing to highDCAD diets, an obvious solution is to limit K fertilization of the forage crop to avoid luxury consumption of K. However, some forages may have reduced yield and increased winter kill if K concentrations are less than 2.0%, particularly alfalfa. Thus, producing alfalfa with less than 2% K may not be profitable, especially in northern regions. In addition to decreasing forage K, the producer can also increase the Cl content of the forages, and the resulting DCAD will be more favorable for the late-gestation cows
Meta-Stable Dynamical Supersymmetry Breaking Near Points of Enhanced Symmetry
We show that metastable supersymmetry breaking is generic near certain
enhanced symmetry points of gauge theory moduli spaces. Our model consists of
two sectors coupled by a singlet and combines dynamical supersymmetry breaking
with an O'Raifeartaigh mechanism in terms of confined variables. All relevant
mass parameters, including the supersymmetry breaking scale, are generated
dynamically. The metastable vacua appear as a result of a balance between
non-perturbative and perturbative quantum effects along a pseudo-runaway
direction.Comment: 27 pages, harvmac, 6 figure
Comparing Evapotranspiration from Eddy Covariance Measurements, Water Budgets, Remote Sensing, and Land Surface Models over Canada
This study compares six evapotranspiration ET products for Canada’s landmass, namely, eddy covariance EC measurements; surface water budget ET; remote sensing ET from MODIS; and land surface model (LSM) ET from the Community Land Model (CLM), the Ecological Assimilation of Land and Climate Observations (EALCO) model, and the Variable Infiltration Capacity model (VIC). The ET climatology over the Canadian landmass is characterized and the advantages and limitations of the datasets are discussed. The EC measurements have limited spatial coverage, making it difficult for model validations at the national scale. Water budget ET has the largest uncertainty because of data quality issues with precipitation in mountainous regions and in the north. MODIS ET shows relatively large uncertainty in cold seasons and sparsely vegetated regions. The LSM products cover the entire landmass and exhibit small differences in ET among them. Annual ET from the LSMs ranges from small negative values to over 600 mm across the landmass, with a countrywide average of 256 ± 15 mm. Seasonally, the countrywide average monthly ET varies from a low of about 3 mm in four winter months (November–February) to 67 ± 7 mm in July. The ET uncertainty is scale dependent. Larger regions tend to have smaller uncertainties because of the offset of positive and negative biases within the region. More observation networks and better quality controls are critical to improving ET estimates. Future techniques should also consider a hybrid approach that integrates strengths of the various ET products to help reduce uncertainties in ET estimation
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