244 research outputs found

    The Benefits of Peer Review and a Multisemester Capstone Writing Series on Inquiry and Analysis Skills in an Undergraduate Thesis.

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    This study examines the relationship between the introduction of a four-course writing-intensive capstone series and improvement in inquiry and analysis skills of biology senior undergraduates. To measure the impact of the multicourse write-to-learn and peer-review pedagogy on student performance, we used a modified Valid Assessment of Learning in Undergraduate Education rubric for Inquiry and Analysis and Written Communication to score senior research theses from 2006 to 2008 (pretreatment) and 2009 to 2013 (intervention). A Fisher-Freeman-Halton test and a two-sample Student's t test were used to evaluate individual rubric dimensions and composite rubric scores, respectively, and a randomized complete block design analysis of variance was carried out on composite scores to examine the impact of the intervention across ethnicity, legacy (e.g., first-generation status), and research laboratory. The results show an increase in student performance in rubric scoring categories most closely associated with science literacy and critical-thinking skills, in addition to gains in students' writing abilities

    Risk of Climate-Related Impacts on Global Rangelands – A Review and Modelling Study

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    Climate change threatens the ability of global rangelands to provide food, support livelihoods and deliver important ecosystems services. The extent and magnitude of potential impacts are however poorly understood. In this study, we review the risk of climate impacts along the rangeland systems food supply chain. We also present results from biophysical modelling simulations and spatial data analyses to identify where and to what extent rangelands may be at climatic risk. Although a quantification of the net impacts of climate change on rangeland production systems is beyond the reach of our current understanding, there is strong evidence that there will be impacts throughout the supply chain, from feed and animal production to processing, storage, transport, retailing and human consumption. Regarding grazing biomass production, this study finds that mean herbaceous biomass is projected to decrease across global rangelands between 2000 and 2050 under RCP 8.5 (-4.7%), while inter- (year-to-year) and intra- (month-to-month) annual variabilities are projected to increase (+21.3% and +8.2%, respectively). These averaged global estimates mask large spatial heterogeneities, with 74% of global rangeland area projected to experience a decline in mean biomass, 64% an increase in inter-annual variability and 54% an increase in intra-annual variability. The potentially most damaging vegetation trends for livestock production (i.e., simultaneous decreases in mean biomass and increases in inter-annual variability) are projected to occur in rangeland communities that are currently the most vulnerable (here, with the lowest livestock productivities and economic development levels and with the highest projected increases in human population densities). Large uncertainties remain as to climate futures and the exposure and responses of the interlinked human and natural systems to climatic changes over time. Consequently, adaptation choices will need to build on robust methods of designing, implementing and evaluating detailed development pathways, and account for a wide range of possible futures

    Scribble modulates the MAPK/Fra1 pathway to disrupt luminal and ductal integrity and suppress tumour formation in the mammary gland

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    Polarity coordinates cell movement, differentiation, proliferation and apoptosis to build and maintain complex epithelial tissues such as the mammary gland. Loss of polarity and the deregulation of these processes are critical events in malignant progression but precisely how and at which stage polarity loss impacts on mammary development and tumourigenesis is unclear. Scrib is a core polarity regulator and tumour suppressor gene however to date our understanding of Scrib function in the mammary gland has been limited to cell culture and transplantation studies of cell lines. Utilizing a conditional mouse model of Scrib loss we report for the first time that Scrib is essential for mammary duct morphogenesis, mammary progenitor cell fate and maintenance, and we demonstrate a critical and specific role for Scribble in the control of the early steps of breast cancer progression. In particular, Scrib-deficiency significantly induced Fra1 expression and basal progenitor clonogenicity, which resulted in fully penetrant ductal hyperplasia characterized by high cell turnover, MAPK hyperactivity, frank polarity loss with mixing of apical and basolateral membrane constituents and expansion of atypical luminal cells. We also show for the first time a role for Scribble in mammalian spindle orientation with the onset of mammary hyperplasia being associated with aberrant luminal cell spindle orientation and a failure to apoptose during the final stage of duct tubulogenesis. Restoring MAPK/Fra1 to baseline levels prevented Scrib-hyperplasia, whereas persistent Scrib deficiency induced alveolar hyperplasia and increased the incidence, onset and grade of mammary tumours. These findings, based on a definitive genetic mouse model provide fundamental insights into mammary duct maturation and homeostasis and reveal that Scrib loss activates a MAPK/Fra1 pathway that alters mammary progenitor activity to drive premalignancy and accelerate tumour progression

    Livestock, land and the environmental limits of animal source-food consumption

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    The increase in global consumption of animal source food (ASF) (by more than 40kg/person/year in the last 25 years) has driven livestock production systems in many countries towards intensification. This has significant consequences for land use. Identifying how best to navigate the trade-offs of using land for livestock production depends on understanding what is happening at a local level since there are large regional differences in trends for both supply and demand. Species and production system are also important determinants of land use, but it is the issue of providing sufficient feed for pigs and poultry and for dairy intensification that causes most concern. Producing traditional feeds (grains and soybean meal) competes with arable land used to produce human food. Thus research on increasing the efficient use of feed resources and on identifying new feed resources are both critical to achieve more sustainable livestock production systems, as is policy research on managing demand

    Electrically pumped WSe2-based light-emitting van der Waals heterostructures embedded in monolithic dielectric microcavities

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    Vertical stacking of atomically thin layered materials opens new possibilities for the fabrication of heterostructures with favorable optoelectronic properties. The combination of graphene, hexagonal boron nitride and semiconducting transition metal dichalcogenides allows fabrication of electroluminescence (EL) devices, compatible with a wide range of substrates. Here, we demonstrate a full integration of an electroluminescent van der Waals heterostructure in a monolithic optical microcavity made of two high reflectivity dielectric distributed Bragg reflectors (DBRs). Owing to the presence of graphene and hexagonal boron nitride protecting the WSe2 during the top mirror deposition, we fully preserve the optoelectronic behaviour of the device. Two bright cavity modes appear in the EL spectrum featuring Q-factors of 250 and 580 respectively: the first is attributed directly to the monolayer area, while the second is ascribed to the portion of emission guided outside the WSe2 island. By embedding the EL device inside the microcavity structure, a significant modification of the directionality of the emitted light is achieved, with the peak intensity increasing by nearly two orders of magnitude at the angle of the maximum emission compared with the same EL device without the top DBR. Furthermore, the coupling of the WSe2 EL to the cavity mode with a dispersion allows a tuning of the peak emission wavelength exceeding 35 nm (80 meV) by varying the angle at which the EL is observed from the microcavity. This work provides a route for the development of compact vertical-cavity surface-emitting devices based on van der Waals heterostructures

    WSe2 Light-Emitting Tunneling Transistors with Enhanced Brightness at Room Temperature

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    Monolayers of molybdenum and tungsten dichalcogenides are direct bandgap semiconductors, which makes them promising for optoelectronic applications. In particular, van der Waals heterostructures consisting of monolayers of MoS2 sandwiched between atomically thin hexagonal boron nitride (hBN) and graphene electrodes allows one to obtain light emitting quantum wells (LEQWs) with low-temperature external quantum efficiency (EQE) of 1%. However, the EQE of MoS2- and MoSe2-based LEQWs shows behavior common for many other materials: it decreases fast from cryogenic conditions to room temperature, undermining their practical applications. Here we compare MoSe2 and WSe2 LEQWs. We show that the EQE of WSe2 devices grows with temperature, with room temperature EQE reaching 5%, which is 250× more than the previous best performance of MoS2 and MoSe2 quantum wells in ambient conditions. We attribute such different temperature dependences to the inverted sign of spin–orbit splitting of conduction band states in tungsten and molybdenum dichalcogenides, which makes the lowest-energy exciton in WSe2 dark

    What do people with lung cancer and stroke expect from patient navigation?: A qualitative study in Germany

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    Objective This qualitative study investigated patients' needs and wishes in relation to patient navigation. Design A qualitative interview study was conducted. Participants were invited to take part in three in-depth interviews over a period of 6-12 months. Thematic analysis was used. Setting Interviewees were sought in the Berlin metropolitan area of Germany in academic university hospitals, in rehabilitation clinics and through self-help organisations. Participants The sample consisted of individuals diagnosed with lung cancer (n=20) or stroke (n=20). Results From the perspective of interviewees, patient navigators should function as consistent contact persons, present during the whole care trajectory. Their role would be to guide patients through an often confusing healthcare landscape, offering practical, advisory and emotional assistance corresponding to patients' needs. The study shows that-independent of the disease-participants had similar expectations and needs regarding support from navigators. Conclusion For chronic and complex diseases-as is the case with lung cancer and stroke-it appears less important for navigators to fulfil disease-specific tasks. Rather, they should ensure that patients' more general needs, in relation to social, practical and emotional support, are met in a way that suits their individual wishes. Following these results, patient navigation programmes might be designed to include generic elements, which should then be adapted to the infrastructure in a particular healthcare region and to the particularities of a specific healthcare system

    Cloning and expression of islandisin, a new thermostable subtilisin from Fervidobacterium islandicum, in Escheria coli

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    A gene encoding a subtilisin-like protease, designated islandisin, from the extremely thermophilic bacterium Fervidobacterium islandicum (DSMZ 5733) was cloned and actively expressed in Escherichia coli. The gene was identified by PCR using degenerated primers based on conserved regions around two of the three catalytic residues (Asp, His, and Ser) of subtilisin-like serine protease-encoding genes. Using inverse PCR regions flanking the catalytic residues, the gene could be cloned. Sequencing revealed an open reading frame of 2,106 bp. The deduced amino acid sequence indicated that the enzyme is synthesized as a proenzyme with a putative signal sequence of 33 amino acids (aa) in length. The mature protein contains the three catalytic residues (Asp177, His215, and Ser391) and has a length of 668 aa. Amino acid sequence comparison and phylogenetic analysis indicated that this enzyme could be classified as a subtilisin-like serine protease in the subgroup of thermitase. The whole gene was amplified by PCR, ligated into pET-15b, and successfully expressed in E. coli BL21(DE3)pLysS. The recombinant islandisin was purified by heat denaturation, followed by hydroxyapatite chromatography. The enzyme is active at a broad range of temperatures (60 to 80°C) and pHs (pH 6 to 8.5) and shows optimal proteolytic activity at 80°C and pH 8.0. Islandisin is resistant to a number of detergents and solvents and shows high thermostability over a long period of time (up to 32 h) at 80°C with a half-life of 4 h at 90°C and 1.5 h at 100°

    Can routine register data be used to identify vulnerable lung cancer patients of suboptimal care in a German comprehensive cancer centre?

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    Objectives Several patient factors have been described to influence access to optimal cancer care like socioeconomic factors or place of residence. In this study, we investigate whether data routinely collected in a clinical cancer registry can be used to identify populations of lung cancer patients with increased risk of not receiving optimal cancer care.Methods We analysed data of 837 lung cancer patients extracted from the clinical cancer registry of a German university hospital. We compared patient populations by two indicators of optimal care, namely implementation of tumour board meeting recommendations as well as the timeliness of care.Results There was a high rate of implementation of tumour board meeting recommendations of 94.4%. Reasons for non-implementation were mainly a patient's own wish or a worsening of the health situation. Of all patient parameters, only tumour stage was associated with the two optimal care indicators.Conclusion Using routine data from a clinical cancer registry, we were not able to identify patient populations at risk of not getting optimal care and the implementation of guideline-conform care appeared to be very high in this setting. However, limitations were the ambiguity of optimal care indicators and availability of parameters predictive for patients' vulnerability.Clinical epidemiolog
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