184 research outputs found
What Drives a Paler Shade of โRedโ in Mississippi State?
Over the years, as a result of depopulation, the population in Mississippi State has fallen by almost half. Moreover, traditionally Mississippi has been considered one of the โdeepโ southern states (Key, 1949). They are very conservative in terms of political position, and they have largely supported โRedโ or the Republican Party, for the last several decades. However, the conservatism of the south is now challenged by the Democratic Party, and trends have been changing gradually in the south, including Mississippi State in recent history. In this paper, I investigate what drives the paler shade of โRedโ in the southern states. In particular, I examine some characteristics of political position in Mississippi, one of the most strongly conservative states in the United States, identifying certain relationships between political preferences and demographic, economic and social factors. Keywords: Southern Politics, Political change, Demographic factors in politic
Does Governmental Condition Really Matter in Charter School Adoption?
Charter schools are generally considered to be implemented in order to achieve the educational needs and desires that parents have for their children, according to the school choice model. However, adoption of charter schools can also depend on various government conditions, such as the availability of resources. Thus, the purpose of this study is to examine whether charter schools are more commonly adopted under favorable government conditions. Using a panel data set from 45 counties in California between 2001 and 2012, our analysis demonstrates that charter schools are more commonly adopted when the government has many financial slacks. Keywords: charter schools, policy diffusion, policy adoptio
Identification and characterisation of potential bacteriocins with biological activity against Clostridium difficile from environmental samples
Recently, the incidence of Clostridium difficile infection (CDI) has been decreasing but still presents a real threat as one of the common causes of nosocomial infection. It represents a real challenge in healthcare settings as one of the main causes of CDI is the use of commonly prescribed broad spectrum antibiotics. Effective infection control along with limiting the use of broad spectrum antibiotics can play their part in reducing CDI but fundamental need for an alternative to antibiotic treatment regime for CDI need to be addressed. Narrow spectrum, antimicrobial peptide bacteriocins can offer a viable alternative to antibiotics.
This research was designed to isolate and identify novel bacterocins from environmental samples that are active against C. difficile by a screening of heat treated, and non-heat treated sewage and faecal samples. 12 environmental isolates were found to have an inhibitory effect on indicator strain C. difficile strain CD630 out of which 8 environmental isolates (S2, S3, S6, S7, S8, S9, S10 and S11) exhibited inhibitory effect on growth of at least 3 of 5 clinically relevant C. difficile strains such as EK28, CD630, DH196, DH478 and R20291. Greatest activity was observed on isolate S2 on all five C. difficile strains. Growth curve analysis of all environmental isolates active against C. difficile revealed that isolate S2 showed significantly slower growth rate compare to other isolates that had growth rates similar to or faster than CD630. Gram staining and 16s rRNA sequencing revealed most of the environmental isolates obtained active against C. difficile belonged to the Enterococcus group (S2, S3, S4, S6, S7 and S8) whereas others (S9, S10 and S11) were different species of Clostridium group. Other investigations to determine the identity of isolate S2 confirmed isolate S2 as Enterococcus. Whole genome sequencing of S2 was done to identify the exact species of Enterococcus S2.
CSF or filtrate obtained from isolate S2 showed inhibition of the growth of CD630 in growing medium and increasing the percentage of the filtrate of isolate exhibited increased inhibition of the growth of CD630. Inhibitory effect of the filtrate of isolate S2 on indicator strain was proteases (proteinase K and trypsin) sensitive. The concentrated filtrate of isolate S2, when spotted on a lawn of CD630, exhibited the zone of inhibition of growth of CD630 as well as other strains whereas not concentrated CFS of isolate S2 didn't. CFS of isolate S2 was active on CD630 till critical dilution of 1 in 20ml. CFS of isolate S2 induced with hydrogen peroxide or co-culturing with different Enterococcus gave a more significant zone of clearance than that of Mitomycin C which is the well-known agent to induce a stress response that may increase the production of bacteriocin. The active ingredient in CFS of isolate S2 that gives a zone of clearance on CD630 is both effective in low and normal room temperature. However, the active component may be relatively unstable as its activity faded over a period of time. Concentrated CFS of isolate S2 did not have any zone of clearance when heat treated. SDS-PAGE analysis of CFS of isolate S2 has shown a presence of many protein molecules of size varying from 25-180 kDa from which active component of CFS of isolate S2 will need to be identified.
Most of the experimental data obtained from this investigation provide a good indication of the potential production of protein-based antimicrobial substance like bacteriocin active against C. difficile from environmental isolate S2, but further experiments in future are of paramount importance to confirm potential bacteriocin from isolate S2 active against C. difficile and its possible potential as antimicrobial substance
Credit Rating Inflation during the 2000s: Lessons from the U.S. State Governments
The recent subprime mortgage crisis in 2008 was considered as resulted partly from the credit rating inflation of subprime mortgage bonds. The credit rating market of state governments may face the same risk of credit rating inflation as that witnessed during the recent recession. In this paper, we attempt to examine whether the credit ratings of state governments are inflated, and whether they are accurately reflected in financial or economic conditions. By using a data set from 1999 to 2010, we find that some credit rating agencies don't reflect financial or economic conditions of state governments appropriately and statistically, and we prove that some credit rating results are affected by characteristics other than financial or economic factors in boom years. Thus, in order to prevent the governmental bond markets from similar credit rating risks in 2008, it needs to investigate whether credit ratings of state governments are inflated.
Keywords: Credit Rating Inflation; State Governments; Credit Rating Agency; Bond Ratings
JEL Classifications: E5; G2
Efficient Exploration of Bus-Based System-on-Chip Architectures
Separation between computation and communication
in system design allows system designers to explore the communication
architecture independently after component selection and
mapping decision is made. In this paper, we present an iterative
two-step exploration methodology for bus-based on-chip communication
architecture for multitask applications. We assume that
the memory traces from the processing components are given.
The proposed methodology uses a static performance estimation
technique extended for multitask applications to reduce the design
space quickly and drastically and applies a trace-driven simulation
to the reduced set of design candidates for accurate performance
estimation. For the case that local memory traffics as well as
shared memory traffics are involved in bus contention, memory
allocation is considered as an important axis of the design space
in our technique. Experimental results show that the proposed
methodology achieves significant performance gain by optimizing
on-chip communication only, up to almost 100% compared with
an initial single shared bus architecture, in both two real-life
examples, a four-Channel digital video recorder and an equalizer
for OFDM DVB-T receiverThis work
was supported by the National Research Laboratory Program under Grant
M1-0104-00-0015 and the IT Leading Research and Development Support
Project funded by Korean MIC
Investment Earnings as a Countercyclical Tool: Evidence from U.S. State Governments
Budget stabilization funds (BSFs) play an important role as a safety device for countercyclical fiscal capacity (CCFC) in the United States. However, while BSFs take on a kind of allowance for a contingent budget deficit, state governments can't expect high return on the money because the BSFs should be used immediately. They can alternatively provide profits from short-term investment earnings with safety and liquidity. Thus, the purpose of this study is to examine whether investment earnings decrease the volatility of total general fund expenditures (GFEs) and improve budget performance in state government. By using OLS regression models with a paneled data set ranging from 2002 to 2013, this study concludes that investment earnings increase the volatility of GFEs, while the generally accepted countercyclical tools such as BSFs and UUBs reduce it. In addition, it also finds that investment earnings are a source of better performance in state government.
Keywords: investment earning, budget performance, countercyclical fiscal capacity (CCFC), budget stabilization fund (BSF)
JEL Classifications: E6, H
Schedule-Aware Performance Estimation of Communication Architecture for Efficient Design Space Exploration
In this paper,we are concerned about performance estimation
of bus-based communication architectures assuming that
task partitioning and scheduling on processing elements are already
determined. Since communication overhead is dynamic and
unpredictable due to bus contention, a simulation-based approach
seems inevitable for accurate performance estimation. However,
it is too time-consuming to be used for exploring the wide design
space of bus architectures. We propose a static performance-estimation
technique based on a queueing analysis assuming that the
memory traces and the task schedule information are given. We
use this static estimation technique as the first step in our design
space exploration framework to prune the design space drastically
before applying a simulation-based approach to the reduced design
space. Experimental results show that the proposed technique
is several orders of magnitude faster than a trace-driven simulation
while keeping the estimation error within 10% consistently in
various communication architecture configurations.This work was supported by the National Research Laboratory under Program
M1-0104-00-0015, Brain Korea 21 Project, and the IT-SoC project. ICT
at Seoul National University provided research facilities for this study
Arrayed CRISPR screen with image-based assay reliably uncovers host genes required for coxsackievirus infection
Pooled CRISPR screens based on lentiviral systems have been widely applied to identify the effect of gene knockout on cellular phenotype. Although many screens were successful, they also have the limitation that genes conferring mild phenotypes or those essential for growth can be overlooked, as every genetic perturbation is incorporated in the same population. Arrayed screens, on the other hand, incorporate a single genetic perturbation in each well and could overcome these limitations. However, arrayed screens based on siRNA-mediated knockdown were recently criticized for low reproducibility caused by incomplete inhibition of gene expression. To overcome these limitations, we developed a novel arrayed CRISPR screen based on a plasmid library expressing a single guide RNA (sgRNA) and disrupted 1514 genes, encoding kinases, proteins related to endocytosis, and Golgi-localized proteins, individually using 4542 sgRNAs (three sgRNAs per gene). This screen revealed host factors required for infection by coxsackievirus B3 (CVB3) from Picornaviridae, which includes human pathogens causing diverse diseases. Many host factors that had been overlooked in a conventional pooled screen were identified for CVB3 infection, including entry-related factors, translational initiation factors, and several replication factors with different functions, demonstrating the advantage of the arrayed screen. This screen was quite reliable and reproducible, as most genes identified in the primary screen were confirmed in secondary screens. Moreover, ACBD3, whose phenotype was not affected by siRNA-mediated knockdown, was reliably identified. We propose that arrayed CRISPR screens based on sgRNA plasmid libraries are powerful tools for arrayed genetic screening and applicable to larger-scale screens.
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