321 research outputs found
Seismic Fluidization and Foundation Behavior
Field observations of seismic settlements of foundations on granular soils due to shear flow rather than densification or liquefaction are explained in terms of the concept of seismic fluidization. The theory is briefly reviewed and used to derive seismic bearing capacity factors for shallow foundations from the standard static formulas. The reduction of bearing capacity as accelerations increase triggers incremental settlement whenever the ground acceleration exceeds some critical level whose value depends on the static design factor of safety. The total seismic settlement can be computed for a particular earthquake record by a modified sliding block approach or related to standardized incremental displacement curves for generalized earthquakes
The Trans-Pacific Partnership Agreement: Looking Ahead to the Next Steps
Pressure has been building for the conclusion of the 12-country Trans-Pacific Partnership (TPP) negotiations. Getting the deal done is important, but the TPP is not just another free trade agreement (FTA). It represents the chance to set a trade agenda for the future across a wide range of topics for countries throughout the Asia-Pacific region. This means that the agreement should not be settled in haste. More importantly, it also means that key decisions need to be reached about broader issues related to the institutional structure of the TPP. These decisions must be made now, before the deal is closed, on issues such as how to create the TPP as a living agreement, the formation of a TPP Secretariat, and the clarification of entry conditions for future members such as the People’s Republic of China (PRC). These choices must be made deliberately and carefully even while officials are struggling with reaching closure on the most highly sensitive issues still remaining in the agreement. It will not be easy, but wise decisions are necessary now to ensure the long-term success of the TPP
Exposure of bakery and pastry apprentices to airborne flour dust using PM2.5 and PM10 personal samplers
<p>Abstract</p> <p>Background</p> <p>This study describes exposure levels of bakery and pastry apprentices to flour dust, a known risk factor of occupational asthma.</p> <p>Methods</p> <p>Questionnaires on work activity were completed by 286 students. Among them, 34 performed a series of two personal exposure measurements using a PM<sub>2.5 </sub>and PM<sub>10 </sub>personal sampler during a complete work shift, one during a cold ("winter") period, and the other during a hot ("summer") period.</p> <p>Results</p> <p>Bakery apprentices experience greater average PM<sub>2.5 </sub>and PM<sub>10 </sub>exposures than pastry apprentices (p < 0.006). Exposure values for both particulate fractions are greater in winter (average PM<sub>10 </sub>values among bakers = 1.10 mg.m<sup>-3 </sup>[standard deviation: 0.83]) than in summer (0.63 mg.m<sup>-3 </sup>[0.36]). While complying with current European occupational limit values, these exposures exceed the ACGIH recommendations set to prevent sensitization to flour dust (0.5 mg.m<sup>-3</sup>). Over half the facilities had no ventilation system.</p> <p>Conclusion</p> <p>Young bakery apprentices incur substantial exposure to known airways allergens, a situation that might elicit early induction of airways inflammation.</p
Single Molecule Conformational Memory Extraction: P5ab RNA Hairpin
Extracting kinetic models from single
molecule data is an important
route to mechanistic insight in biophysics, chemistry, and biology.
Data collected from force spectroscopy can probe discrete hops of
a single molecule between different conformational states. Model extraction
from such data is a challenging inverse problem because single molecule
data are noisy and rich in structure. Standard modeling methods normally
assume (i) a prespecified number of discrete states and (ii) that
transitions between states are Markovian. The data set is then fit
to this predetermined model to find a handful of rates describing
the transitions between states. We show that it is unnecessary to
assume either (i) or (ii) and focus our analysis on the zipping/unzipping
transitions of an RNA hairpin. The key is in starting with a very
broad class of non-Markov models in order to let the data guide us
toward the best model from this very broad class. Our method suggests
that there exists a folding intermediate for the P5ab RNA hairpin
whose zipping/unzipping is monitored by force spectroscopy experiments.
This intermediate would not have been resolved if a Markov model had
been assumed from the onset. We compare the merits of our method with
those of others
Spina bifida-predisposing heterozygous mutations in Planar Cell Polarity genes and Zic2 reduce bone mass in young mice
Fractures are a common comorbidity in children with the neural tube defect (NTD) spina bifida. Mutations in the Wnt/planar cell polarity (PCP) pathway contribute to NTDs in humans and mice, but whether this pathway independently determines bone mass is poorly understood. Here, we first confirmed that core Wnt/PCP components are expressed in osteoblasts and osteoclasts in vitro. In vivo, we performed detailed µCT comparisons of bone structure in tibiae from young male mice heterozygous for NTD-associated mutations versus WT littermates. PCP signalling disruption caused by Vangl2 (Vangl2Lp/+) or Celsr1 (Celsr1Crsh/+) mutations significantly reduced trabecular bone mass and distal tibial cortical thickness. NTD-associated mutations in non-PCP transcription factors were also investigated. Pax3 mutation (Pax3Sp2H/+) had minimal effects on bone mass. Zic2 mutation (Zic2Ku/+) significantly altered the position of the tibia/fibula junction and diminished cortical bone in the proximal tibia. Beyond these genes, we bioinformatically documented the known extent of shared genetic networks between NTDs and bone properties. 46 genes involved in neural tube closure are annotated with bone-related ontologies. These findings document shared genetic networks between spina bifida risk and bone structure, including PCP components and Zic2. Genetic variants which predispose to spina bifida may therefore independently diminish bone mass
Consumer vulnerability and the transformative potential of Internet shopping: An exploratory case study
Ten million individuals in the UK who suffer from long-term illness, impairments or disability can be considered as vulnerable consumers (Office for Disability Issues, 2010). Despite this, there are few studies on the use of the Internet for grocery shopping by the disabled and none which offers an understanding of the multiple facets of consumer vulnerability. The purpose of this study is to contextualise the use of the Internet for grocery shopping using an exploratory case to provide fresh insights into the 'actual' vulnerability of "Danni" – a disabled housewife and mother. The consumer focussed methods used here were combined multiple complementary approaches. The findings illustrate that whilst the use of the Internet reduces the impracticalities of shopping in-store, the normalcy afforded to Danni through shopping in-store (including her sense of self) was not met by the technological offerings. The paradoxes associated with using online provision and the strategies adopted to manage these by Danni demonstrate engagement/disengagement and assimilation/isolation. Policy implications and insights for retailers are provided
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Proactive familial cancer risk assessment: A UK primary care study.
BACKGROUND: Family-history assessment can identify individuals above population-risk for cancer to enable targeted Screening, Prevention and Early Detection (SPED). Family History Questionnaire Service (FHQS) is a resource-efficient patient-facing online tool to facilitate this. In the UK, cancer-risk assessment is usually only offered to concerned individuals pro-actively self-presenting to their general practitioner, leading to inequity in accessing SPED in the community. AIM: To improve access to community cancer genetic risk assessment and explore barriers to uptake. DESIGN AND SETTING: Service development project of a digital pathway using the FHQS for cancer-risk assessment across four general practices within the clinical remit of the South West Thames Centre for Genomics (SWTCG) METHODS: 3100 individuals aged 38-50 years were invited to complete the FHQS through either text message or email. A random selection of 100 non-responders were contacted to determine barriers to uptake. RESULTS: 304/3100 (9.8%) registered for the FHQS. Responders were more likely to be British (63% vs 47%, P<0.001), speak English as their main language (92% vs 76%, P<0.001) and not require an interpreter (99.6% vs 94.9%, P=0.001). Of 304 responders, 158 (52%) were automatically identified as at population-risk without full family-history review. Of the remaining 146 responders, 52 (36%) required either additional screening referral (N=23), genetics referral (N=15), and/or advice to relatives (N=18). Of 100 non-responders contacted, eight had incorrect contact details and 53 were contactable. Reasons for not responding included not receiving invitation details (N=26), losing the invitation (N=5), or forgetting (N=4). CONCLUSION: The FHQS can be used as part of a low-resource primary care pathway to identify individuals in the community above population-risk for cancer requiring action. This study highlights barriers to uptake requiring consideration to maximise impact and minimise inequity
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