Isolating intrinsic noise sources in a stochastic genetic switch

The stochastic mutual repressor model is analysed using perturbation methods. This simple model of a gene circuit consists of two genes and three promotor states. Either of the two protein products can dimerize, forming a repressor molecule that binds to the promotor of the other gene. When the repressor is bound to a promotor, the corresponding gene is not transcribed and no protein is produced. Either one of the promotors can be repressed at any given time or both can be unrepressed, leaving three possible promotor states. This model is analysed in its bistable regime in which the deterministic limit exhibits two stable fixed points and an unstable saddle, and the case of small noise is considered. On small time scales, the stochastic process fluctuates near one of the stable fixed points, and on large time scales, a metastable transition can occur, where fluctuations drive the system past the unstable saddle to the other stable fixed point. To explore how different intrinsic noise sources affect these transitions, fluctuations in protein production and degradation are eliminated, leaving fluctuations in the promotor state as the only source of noise in the system. Perturbation methods are then used to compute the stability landscape and the distribution of transition times, or first exit time density. To understand how protein noise affects the system, small magnitude fluctuations are added back into the process, and the stability landscape is compared to that of the process without protein noise. It is found that significant differences in the random process emerge in the presence of protein noise

Talking About, Knowing About HIV/AIDS in Canada: A Rural‐Urban Comparison

Purpose: To explore information exchange about HIV/AIDS among people living in rural and urban communities and to assess the value of social capital theory, as well as demographic factors, in predicting community members’ knowledge of HIV/AIDS and their likelihood of having talked about the disease. Method: A random‐digit dial telephone survey was conducted in 3 rural regions and matched urban communities in Canada during 2006 and 2007. A total of 1,919 respondents (response rate: 22.2%) answered questions about their knowledge of and attitudes toward HIV/AIDS, their social networks, whether they were personally acquainted with a person with HIV/AIDS (PHA), and whether they had ever talked to anyone about HIV/AIDS. Findings: Rurality was a significant predictor of HIV/AIDS knowledge and discussion. Even after controlling for factors such as age and level of education, respondents living in rural regions were less knowledgeable about HIV/AIDS and were less likely to have spoken with others about the disease. Social capital theory was not as strongly predictive as expected, although people with more bridging ties in their social networks were more likely to have discussed the disease, as were those who knew a PHA personally. Conclusion: Rural‐dwelling Canadians are less likely than their urban counterparts to be knowledgeable about HIV/AIDS or to talk about it, confirming reports by PHAs that rural communities tend to be silent about the disease. The findings support policy recommendations for HIV education programs in rural areas that encourage discussion about the disease and personal contact with PHAs.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86990/1/j.1748-0361.2010.00353.x.pd

On the signaling effect of reward-based crowdfunding: (When) do later stage venture capitalists rely more on the crowd than their peers?

Venture capitalists (VCs) make only a small number of investments and are more likely to invest in ventures where other VCs have invested previously. As such, valuable opportunities may be forgone if they are not funded by VCs in the first place. We demonstrate how crowdfunding (CF) can remedy this concern. Using a sample of new technology-based ventures, we reveal that ventures initially funded through reward-based CF can be even more likely than those initially backed by VCs in attracting follow-up funds from VCs. This happens when ventures originally funded via reward-based CF complement the certification they derive from CF with patents and a founding team with a track record of success. In those cases, VCs rely on the crowd more than their peers. Overall, the results suggest that signal complementarity can at least equalize the effectiveness of an a priori inferior and an a priori superior signal

Could time detect a faking-good attitude? A study with the MMPI-2-RF

Background and Purpose: Research on the relationship between response latency (RL) and faking in self-administered testing scenarios have generated contradictory findings. We explored this relationship further, aiming to add further insight into the reliability of self-report measures. We compared RLs and T-scores on the MMPI-2-RF (validity and restructured clinical [RC] scales) in four experimental groups. Our hypotheses were that: the Fake-Good Speeded group would obtain a different completion time; show higher RLs than the Honesty Speeded Group in the validity scales; show higher T-Scores in the L-r and K-r scales and lower T-scores in the F-r and RC scales; and show higher levels of tension and fatigue. Finally, the impact of the speeded condition in malingering was assessed. Materials and Methods: The sample was comprised of 135 subjects (M = 26.64; SD = 1.88 years old), all of whom were graduates (having completed at least 17 years of instruction), male, and Caucasian. Subjects were randomly assigned to four groups: Honesty Speeded, Fake-Good Speeded, Honesty Un-Speeded, and Fake-Good Un-Speeded. A software version of the MMPI-2-RF and Visual Analog Scale (VAS) were administered. To test the hypotheses, MANOVAs and binomial logistic regressions were run. Results: Significant differences were found between the four groups, and particularly between the Honest and Fake-Good groups in terms of test completion time and the L-r and K-r scales. The speeded condition increased T-scores in the L-r and K-r scales but decreased T-scores in some of the RC scales. The Fake groups also scored higher on the VAS Tension subscale. Completion times for the first and second parts of the MMPI-2-RF and T-scores for the K-r scale seemed to predict malingering. Conclusion: The speeded condition seemed to bring out the malingerers. Limitations include the sample size and gender bias

Histological correlation of nasal mass: a five year retrospective and prospective study

Background:The presence of mass in the nose may seem to be a simple problem; however it raises several issues about the differential diagnosis. The aim of this study is to evaluate the histological profile of nasal masses in the environment.Methods:This is a retrospective and prospective study of nasal masses during a period of five years of patients presenting to the clinician in our hospital.Results:A total of 90 patients were analysed age ranging from 3 to 80 years. Majority of patients were in the second decade. Sex wise distribution showed a male to female ratio of 2.2:1. The main presenting symptom was nasal obstruction seen in 53.30% patients, while proptosis was seen only in malignant lesion. Among a total of 90 lesions in the nasal cavity 81.1% were benign, 15.5 % were malignant and 3.3% were inadequate sample The commonest non neoplastic lesion was nasal polyp which comprised about 83.33% followed by rhinoscleroma, while the commonest benign neoplastic lesion was papilloma and comprised about 42.10% and squamous cell carcinoma was the most common malignant neoplastic lesion in the nasal cavity and comprised about 42.85%. Most patients with benign lesion were in the second decade. Malignant lesions occurred mainly after fifth decade, while inadequacy of sample was seen in the second decade.  Conclusion: Males are more commonly affected then females. Nasal obstruction is the commonest symptom Simple inflammatory nasal polyp is still the commonest histological pattern seen while papilloma being the most common benign lesion and squamous cell carcinoma the most common malignant lesion.

The supersymmetric Ward identities on the lattice

Supersymmetric (SUSY) Ward identities are considered for the N=1 SU(2) SUSY Yang Mills theory discretized on the lattice with Wilson fermions (gluinos). They are used in order to compute non-perturbatively a subtracted gluino mass and the mixing coefficient of the SUSY current. The computations were performed at gauge coupling $\beta$=2.3 and hopping parameter $\kappa$=0.1925, 0.194, 0.1955 using the two-step multi-bosonic dynamical-fermion algorithm. Our results are consistent with a scenario where the Ward identities are satisfied up to O(a) effects. The vanishing of the gluino mass occurs at a value of the hopping parameter which is not fully consistent with the estimate based on the chiral phase transition. This suggests that, although SUSY restoration appears to occur close to the continuum limit of the lattice theory, the results are still affected by significant systematic effects.Comment: 34 pages, 7 figures. Typo corrected, last sentence reformulated, reference added. To appear in Eur. Phys. J.

Assessing users’ experience of shared sanitation facilities: A case study of community ablution blocks in Durban, South Africa

Despite significant financial investment, the effective implementation and sustained use of water and sanitation (WATSAN) technologies remains a chimera, with one billion people using unimproved water facilities and two and a half billion not benefitting from adequate sanitation. The poor success rate of WATSAN interventions results from a predominance of supply-driven approaches which lack recipients’ inputs into planning and implementation to ensure that technologies are fully absorbed and adapted to users’ needs. In the academic literature, users’ feedback and experiences of technologies in the post-implementation phase have received scarce attention. The purpose of this study is to investigate users’ experience of sanitation technologies in the early post-implementation phase, when opportunities for remedial intervention are still available. Fieldwork comprising semi-structured interviews was undertaken with users and potential recipients of three community ablution blocks (CABs) in informal settlements around Durban. Results suggest that non-technical aspects such as affordability or cleanliness of the facilities can affect acceptance among the investigated communities. User training is positively associated with higher levels of facility maintenance as well as satisfaction with its functionality. A comparison between users and potential recipients of CABs shows that perceived health benefits, attitudes in case of  problems, and trust are affected by use of the facilities. Conclusions relate to how early post-implementation assessments of users’ experiencecould enhance the process of acceptance and management of the technology, thereby increasing progress towards achievement of the related Millenium Development Goals.Keywords: Ablution blocks, user acceptance, eThekwini municipality, Durban, sanitatio

Pulses for healthy and sustainable food systems: The effect of origin on market price

Pulses are widely acknowledged for their high nutritional value due to high protein content, low content in calories, and low glycemic index; they are a good alternative to animal proteins thus offering a considerable number of social, environmental, and health benefits. Despite pulses being widely acknowledged as healthy and sustainable food, in mainly European countries, consumption is growing but still lower than the recommended level, production is unprofitable in comparison to the current market prices level, and a reduction in harvested area has led to a strong dependence on import for pulses supply. Pulses are particularly fitting to the feature of local food because they can be suitably grown in any context, even in the most complex areas, and consumer interest and awareness of food origin has strongly increased in recent years. Lentils were selected as a case study in this paper that aims to define which features are effective on market price and, in particular, the role of origin declaration on label plays in defining the market price and how the origin attributes may enhance market price and farms competitiveness. The methodological tool for this investigation is the hedonic price model, useful to explain the effects of attributes of pulses affecting the market price. Results contribute to a better understanding of the pulse market, emphasizing that the “origin declaration” on label may have a positive effect on market price

MULTIPLE CUTANEOUS PILOLEIOMYOMA WITH UTERINE FIBROIDS (REED\u27S SYNDROME): A RARE CASE REPORT

Cutaneous leiomyomas comprise approximately 5% of all leiomyomas. Solitary occurrence is more common than generalized. Multiple cutaneous piloleiomyomas are rare, painful and difficult-to-treat benign tumors originating in the arrectores pilorum muscles of the hair follicles. Multiple Cutaneous piloleiomyomas are associated with uterine fibroids in women (Reed\u27s syndrome) and it is a marker of a condition called hereditary leiomyomatosis and renal cell cancer (HLRCC). We report a case of multiple cutaneous piloleiomyoma with uterine fibroid in an adult female. Because of its rarity and association with renal cell cancer, it deserves a mention in literature. KEYWORDS: Cutaneous leiomyoma; Uterine leiomyoma; Painful nodules

MULTIPLE CUTANEOUS PILOLEIOMYOMA WITH UTERINE FIBROIDS (REED'S SYNDROME): A RARE CASE REPORT

Cutaneous leiomyomas comprise approximately 5% of all leiomyomas. Solitary occurrence is more common than generalized. Multiple cutaneous piloleiomyomas are rare, painful and difficult-to-treat benign tumors originating in the arrectores pilorum muscles of the hair follicles. Multiple Cutaneous piloleiomyomas are associated with uterine fibroids in women (Reed's syndrome) and it is a marker of a condition called hereditary leiomyomatosis and renal cell cancer (HLRCC). We report a case of multiple cutaneous piloleiomyoma with uterine fibroid in an adult female. Because of its rarity and association with renal cell cancer, it deserves a mention in literature. KEYWORDS: Cutaneous leiomyoma; Uterine leiomyoma; Painful nodules