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result(s) for
"Rosenzweig, Steven"
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Dangerous Disconnect
2021
Why do politicians use violence as an electoral tactic, and how does it affect voting behavior? Theories of election-related violence focus on the electoral benefits such violence is said to provide, relying on the assumption that when parties and candidates employ violence, they do so based on an accurate assessment of its relative costs and benefits. Far less attention has been paid to the costs of violence as an electoral tactic, including the potential for voter backlash against it. This study provides evidence that voter backlash against violence is more significant than both scholars and politicians tend to assume. Moreover, that backlash can diminish the electoral advantages that violence provides. Combining survey experiments with Kenyan voters and observational data on violence and election outcomes, I find compelling evidence for broad-based voter backlash against violence that undermines its effectiveness as an electoral tactic. At the same time, data from parallel survey experiments and qualitative interviews with Kenyan politicians demonstrate that they underestimate the extent to which violence diminishes their support among voters. The results highlight the often underappreciated costs of violence as an electoral tactic and the role that elite misperceptions can play in its persistence.
Journal Article
Landscape-scale cropping changes in the High Plains: economic and environmental implications
by
Rosenzweig, Steven T
,
Schipanski, Meagan E
in
Agricultural economics
,
Agricultural land
,
Agricultural practices
2019
A global transformation in semi-arid cropping systems is occurring as dryland (non-irrigated) farmers in semi-arid regions shift from crop rotations reliant on year-long bare fallows, called summer fallow, to more intensively cropped systems. Understanding the rate of cropping system intensification at the landscape scale is critical to estimating the economic and environmental implications of this movement. Here, we use high-resolution satellite data to quantify dryland cropping patterns from 2008 to 2016 in the US High Plains. We use these estimates to scale up our previous field-level research in this region on soil carbon, herbicide use, yields, and profitability. Over the nine year study period, the High Plains witnessed a profound shift in cropping systems, as the historically dominant wheat-fallow system was replaced by more intensified rotations as the dominant systems by land area. Out of the 4 million hectares of non-irrigated cropland in the study area, this shift coincided with a 0.5 million-hectare decline in summer fallow and a concurrent increase in alternative (non-wheat) crops. We estimate that, from 2008 to 2016, these patterns resulted in a 0.53 Tg (9%) increase in annual grain production, 80 million USD (10%) increase in annual net farm operating income, substantial reductions in herbicide use, and an increase in C sequestration that corresponds to greenhouse gas reductions of 0.32 million metric tons of CO2 equivalents per year (MMTCO2e yr−1). We project each of these implications to a scenario of potential maximum 100% intensification and estimate that, relative to 2016 levels, herbicide use would be reduced by more than half, grain production would increase by 25%, net operating income would increase by 223 million USD (26%), and greenhouse gases would be reduced by an additional 0.8 MMTCO2e yr−1. The scale of cropping intensification in the High Plains and its environmental and economic impacts has important implications for other regions undergoing similar transformations, and for policy that can either support or hinder these shifts toward more sustainable cropping systems.
Journal Article
The Continuing Evolution of Insulin-like Growth Factor Signaling version 1; peer review: 4 approved
2020
The insulin-like growth factors (IGFs; IGF1/IGF2), known for their regulation of cell and organismal growth and development, are evolutionarily conserved ligands with equivalent peptides present in flies (
D. melanogaster), worms (
C. elegans) among others. Two receptor tyrosine kinases, the IGF1 receptor and the insulin receptor mediate the actions of these ligands with a family of IGF binding proteins serving as selective inhibitors of IGF1/2. This treatise reviews recent findings on IGF signaling in cancer biology and central nervous system function. This includes overexpression of IGF1 receptors in enhancing tumorigenesis, acquired resistance and contributions to metastasis in multiple cancer types. There is accumulating evidence that insulin resistance, a hallmark of type 2 diabetes, occurs in the central nervous system, independent of systemic insulin resistance and characterized by reduced insulin and IGF1 receptor signaling, and may contribute to dementias including Alzheimer's Disease and cognitive impairment. Controversy over the role(s) of IGF signaling in cancer and whether its inhibition would be of benefit, still persist and extend to IGF1's role in longevity and central nervous system function.
Journal Article
Age is measured with systematic measurement error in developing country surveys: A diagnosis and analysis of consequences
2021
Research in political science and other social sciences often relies on survey data to study a range of questions about politics in the developing world. This study identifies systematic measurement error in some of the most frequently used datasets with respect to one commonly employed variable: respondent’s age. It shows evidence of substantial measurement error that is correlated with observable characteristics, and discusses and illustrates the implications for empirical analysis with an example from a recently published study. In doing so, it demonstrates tools for identifying and diagnosing systematic measurement error in survey data, as well as for investigating the robustness of one’s findings when the problem arises.
Journal Article
The peroxidase PRDX1 inhibits the activated phenotype in mammary fibroblasts through regulating c-Jun N-terminal kinases
by
Attaran, Shireen
,
Jezierska-Drutel, Agnieszka
,
Hopkins, Barbara L.
in
Actins - metabolism
,
Animal behavior
,
Animals
2019
Background
Reactive oxygen species (ROS), including hydrogen peroxide, drive differentiation of normal fibroblasts into activated fibroblasts, which can generate high amounts of hydrogen peroxide themselves, thereby increasing oxidative stress in the microenvironment. This way, activated fibroblasts can transition into cancer-associated fibroblasts (CAFs).
Methods
Mammary fibroblasts from either female 8 weeks old PRDX1 knockout and wildtype mice or Balb/c mice were studied for characteristic protein expression using immunofluorescence and immunoblotting. Cancer-associated fibroblasts was examined by transwell migration and invasion assays. The binding of PRDX1 to JNK1 was assessed by co-immuneprecipitation and JNK regulation of CAF phenotypes was examined using the JNK inhibitor SP600125. Extracellular hydrogen peroxide levels were measured by chemiluminescence via the reaction between hypochlorite and luminol. Statistical analyses were done using Students t-test.
Results
We show here PRDX1 activity as an essential switch in regulating the activated phenotype as loss of PRDX1 results in the development of a CAF-like phenotype in mammary fibroblasts. We also show that PRDX1 regulates JNK kinase signaling thereby inhibiting CAF-like markers and CAF invasion. Inhibition of JNK activity reduced these behaviors.
Conclusions
These data suggest that PRDX1 repressed the activated phenotype of fibroblasts in part through JNK inhibition which may present a novel therapeutic option for CAF-enriched cancers such as breast cancer.
Journal Article
Ecosystem Impacts and Productive Capacity of a Multi-Species Pastured Livestock System
by
Maciel, Isabella C. F.
,
Guzman, Aidee
,
Thorbecke, Mariko
in
Agricultural land
,
Agricultural practices
,
Agriculture
2020
Regenerative agriculture is a newly codified approach to agriculture that emphasizes reducing reliance on exogeneous inputs, as well as restoring and enhancing ecosystem services such as soil carbon (C) sequestration. These regenerative agriculture principles suggest that modern livestock systems can be redesigned to better capitalize on animals' ecological niche as biological up cyclers and may be necessary to fully regenerate some landscapes. One example is a multispecies pasture rotation (MSPR) system, which symbiotically stacks multiple animal production enterprises (i.e., chickens, cattle, sheep, and pigs) on one landscape. We conducted a whole-farm life cycle assessment (LCA) of an MSPR in the southeastern United States that was originally converted from degraded cropland. We compared the production outputs, greenhouse gas (GHG) emissions, land footprints, and soil health outcomes to a conventional, commodity (COM) production system of each respective species. Our 20-year MSPR chronosequence of soil C and other soil health indicators shows dramatic improvement since establishment, sequestering an average of 2.29 Mg C ha −1 yr −1 . Incorporation of soil C sequestration into the LCA reduced net GHG emissions of the MSPR by 80%, resulting in a footprint 66% lower than COM. However, when comparing required land between the two systems for food production, MSPR required 2.5 times more land when compared to COM. Thus, while our model indicates that MSPR can simultaneously produce protein while regenerating land, a considerably greater land area is needed when compared to COM. Our results present an important yet paradoxical conclusion on land and food production balance. Should society prioritize an input-intensive, COM system that produces more food from a smaller yet degrading land base? Or, alternatively, should systems such as MSPR that produce less food on a larger, but more ecologically functional landscape be more highly prioritized? These complexities must be considered in the global debate of agricultural practice and land. Our results indicate MSPRs are a useful model for alternative livestock production systems with improved environmental outcomes, but in this study may present considerable land-use tradeoffs.
Journal Article
Rhizosphere priming and plant-mediated cover crop decomposition
by
Kaye, Jason P.
,
Schipanski, Meagan E.
,
Rosenzweig, Steven T.
in
Agricultural ecosystems
,
Agricultural practices
,
agroecosystems
2017
Background and aims Rhizosphere priming occurs when plant belowground carbon (C) allocation influences the rate of soil organic matter (SOM) decomposition. We investigated the effects of priming and plant-mediated cover crop decomposition on agroecosystem C and nitrogen (N) dynamics. Methods Using C stable isotopes, we tracked C and N from corn, clover (Trifolium pratense) and rye (Secale cereale) cover crop litter, and background SOM in plots following clover, rye, or no cover crop (fallow) in 2013 and 2014. Results Corn enhanced the decomposition of N-rich clover cover crop litter in 2013, but there was little evidence of priming of bulk SOM decomposition. There was no corn effect on litterbag decomposition in 2014, likely due to greater soil moisture and temperature in no-corn plots. Corn N uptake per unit of corn-derived CO2 respiration was consistently lower following rye than clover and fallow, suggesting a higher C cost for corn to access N following a rye cover crop. Conclusions This is one of the first field-based studies to provide evidence that plant-mediated litter decomposition potentially provides an important source of plant-available N. Climate and residue quality influence the extent to which corn mediates its own N supply with implications for agroecosystem C and N cycling.
Journal Article
Loss of Expression and Function of SOCS3 Is an Early Event in HNSCC: Altered Subcellular Localization as a Possible Mechanism Involved in Proliferation, Migration and Invasion
by
Rosenzweig, Steven A.
,
Kirkwood, Keith L.
,
Watson, Dennis K.
in
Apoptosis
,
Biochemistry
,
Biology
2012
Suppressor of cytokine signaling 3 (SOCS3) is an inducible endogenous negative regulator of signal transduction and activator of transcription 3 (STAT3). Epigenetic silencing of SOCS3 has been shown in head and neck squamous cell carcinoma (HNSCC), which is associated with increased activation of STAT3. There is scarce information on the functional role of the reduction of SOCS3 expression and no information on altered subcellular localization of SOCS3 in HNSCC.
We assessed endogenous SOCS3 expression in different HNSCC cell lines by RT-qPCR and western blot. Immunofluorescence and western blot were used to study the subcellular localization of endogenous SOCS3 induced by IL-6. Overexpression of SOCS3 by CMV-driven plasmids and siRNA-mediated inhibition of endogenous SOCS3 were used to verify the role of SOCS3 on tumor cell proliferation, viability, invasion and migration in vitro. In vivo relevance of SOCS3 expression in HNSCC was studied by quantitative immunohistochemistry of commercially-available tissue microarrays. Endogenous expression of SOCS3 was heterogeneous in four HNSCC cell lines and surprisingly preserved in most of these cell lines. Subcellular localization of endogenous SOCS3 in the HNSCC cell lines was predominantly nuclear as opposed to cytoplasmic in non-neoplasic epithelial cells. Overexpression of SOCS3 produced a relative increase of the protein in the cytoplasmic compartment and significantly inhibited proliferation, migration and invasion, whereas inhibition of endogenous nuclear SOCS3 did not affect these events. Analysis of tissue microarrays indicated that loss of SOCS3 is an early event in HNSCC and was correlated with tumor size and histological grade of dysplasia, but a considerable proportion of cases presented detectable expression of SOCS3.
Our data support a role for SOCS3 as a tumor suppressor gene in HNSCC with relevance on proliferation and invasion processes and suggests that abnormal subcellular localization impairs SOCS3 function in HNSCC cells.
Journal Article
An ultra-stable redox-controlled self-assembling polypeptide nanotube for targeted imaging and therapy in cancer
by
Verma, Brijesh Kumar
,
Shettar, Abhijith
,
Asampille, Gitanjali
in
Biotechnology
,
Cancer
,
Cancer cells
2018
We introduce a self-assembling polypeptide-based nanotube system having the ability to specifically target cancer cells. The nanotubes target the cancer cell surface through integrin engagement with the help of multiple RGD units present along their surface. While the nanotubes are non-toxic towards cells in general, they can be loaded with suitable drugs to be released in a sustained manner in cancer cells. In addition, the nanotubes can be utilized for cellular imaging using any covalently tagged fluorescent dye. They are stable over a wide range of temperature due to intermolecular disulphide bonds formed during the self-assembly process. At the same time, presence of disulphide bonds provides a redox molecular switch for their degradation. Taken together this system provides a unique avenue for multimodal formulation in cancer therapy.
Journal Article
Realizing Resilient Food Systems
by
DRINKWATER, LAURIE
,
ROSENZWEIG, STEVEN
,
LUNDGREN, JONATHAN G.
in
Agricultural production
,
at-risk population
,
Case Studies
2016
Food systems are under increasing pressure to produce sufficient food for the global population, decrease the environmental impacts of production, and buffer against complex global change. Food security also remains elusive for many populations worldwide. Greater emphasis on food system resilience could reduce these vulnerabilities. We outline integrated strategies that together could foster food system resilience across scales, including (a) integrating gender equity and social justice into food security research and initiatives, (b) increasing the use of ecological processes rather than external inputs for crop production, (c) fostering regionalized food distribution networks and waste reduction, and (d) linking human nutrition and agricultural production policies. Enhancing social–ecological links and fostering adaptive capacity are essential to cope with short-term volatility and longer-term global change pressures. Finally, we highlight regional case studies that have enhanced food system resilience for vulnerable populations. Efforts in these areas could have dramatic impacts on global food system resilience.
Journal Article