743 research outputs found
The Nature of Science: A Perspective from the Philosophy of Science
In a recent article in this journal, Brian Alters (1997) argued that, given the many ways in which the nature of science (NOS) is described and poor student responses to NOS instruments such as Nature of Scientific Knowledge Scale (NSKS), Nature of Science Scale (NOSS), Test on Understanding Science (TOUS), and others, it is time for science educators to reconsider the standard lists of tenets for the NOS. Alters suggested that philosophers of science are authorities on the NOS and that consequently, it would be wise to investigate their views of current NOS tenets. To that end, he conducted a survey of members of the Philosophy of Science Association, and, via various statistical techniques, made claims about the nature and extent of variation among philosophers of science regarding basic beliefs about the NOS.
As three philosophers of science, we laud Altersâ attempt to understand philosophers of scienceâ view on the NOS. We believe, however, that his techniques for investigating this question are inappropriate and that consequently, several of his conclusions are unwarranted. In this comment, we will substantiate these criticisms. In addition, we will address some of the important questions that motivate Altersâ research and attempt to unravel the âbyzantine complexityâ of philosophical views about the NOS. We begin with our concerns regarding Altersâ research. We then provide a taxonomy of philosophic issues; and finally, we suggest some roles for philosophy of science in science teaching and the education of science teachers
'GR 7' Grape
'GR 7' is an early / mid-season red wine grape for use
primarily in red wine blends. It is distinguished from other red
wine grapes grown in cool climates by its high degree of winter
hardiness, adaptation to mechanized production systems, and
ability to survive in older plantings where other red wine grapes
are lost due to tomato and tobacco ringspot virus infections. ?GR
7? is a highly productive, easy to manage cultivar, and is the sixth
wine grape to be developed by the New York State Agricultural
Experiment Station of Cornell University
Functional consequences of seven novel mutations in the CYP11B1 Gene: four mutations associated with nonclassic and three mutations causing classic 11 -Hydroxylase Deficiency
Context: Steroid 11β-hydroxylase (CYP11B1) deficiency (11OHD) is the second most common form of congenital adrenal hyperplasia (CAH). Cases of nonclassic 11OHD are rare compared with the incidence of nonclassic 21-hydroxylase deficiency.
Objective: The aim of the study was to analyze the functional consequences of seven novel CYP11B1 mutations (p.M88I, p.W116G, p.P159L, p.A165D, p.K254_A259del, p.R366C, p.T401A) found in three patients with classic 11OHD, two patients with nonclassic 11OHD, and three heterozygous carriers for CYP11B1 mutations.
Methods: We conducted functional studies employing a COS7 cell in vitro expression system comparing wild-type (WT) and mutant CYP11B1 activity. Mutants were examined in a computational three-dimensional model of the CYP11B1 protein.
Results: All mutations (p.W116G, p.A165D, p.K254_A259del) found in patients with classic 11OHD have absent or very little 11β-hydroxylase activity relative to WT. The mutations detected in patients with nonclassic 11OHD showed partial functional impairment, with one patient being homozygous (p.P159L; 25% of WT) and the other patient compound heterozygous for a novel mild p.M88I (40% of WT) and the known severe p.R383Q mutation. The two mutations detected in heterozygous carriers (p.R366C, p.T401A) also reduced CYP11B1 activity by 23 to 37%, respectively.
Conclusion: Functional analysis results allow for the classification of novel CYP11B1 mutations as causative for classic and nonclassic 11OHD, respectively. Four partially inactivating mutations are predicted to result in nonclassic 11OHD. These findings double the number of mild CYP11B1 mutations previously described as associated with mild 11OHD. Our data are important to predict phenotypic expression and provide important information for clinical and genetic counseling i
Suicides in public places: findings from one English county
Little is known about where suicides take place. We collected data from coronersâ files on all suicides and undetermined deaths in one large English county from 2000 to 2004. The data show that >30% of suicides occurred in public places. A quarter of these involved jumping from a height and nearly a quarter involved car exhaust poisoning. Several sites were associated with multiple methods of suicide. Identifying and managing high-risk locations should be an important part of an overall suicide prevention strategy and is best tackled at local level
Complexity, transparency and time pressure: practical insights into science communication in times of crisis
A global crisis such as the COVID-19 pandemic that started in early 2020 poses significant challenges for how research is conducted and communicated. We present four case studies from the perspective of an interdisciplinary research institution that switched to âcorona-modeâ during the first two months of the crisis, focussing all its capacities on COVID-19-related issues, communicating to the public directly and via media, as well as actively advising the national government. The case studies highlight the challenges posed by the increased time pressure, high demand for transparency, and communication of complexity and uncertainty. The article gives insights into how these challenges were addressed in our research institution and how science communication in general can be managed during a crisis
Optimisation of air cooled, open-cathode fuel cells: Current of lowest resistance and electro-thermal performance mapping
Selecting the ideal operating point for a fuel cell depends on the application and consequent trade-off between efficiency, power density and various operating considerations. A systematic methodology for determining the optimal operating point for fuel cells is lacking; there is also the need for a single-value metric to describe and compare fuel cell performance. This work shows how the âcurrent of lowest resistanceâ can be accurately measured using electrochemical impedance spectroscopy and used as a useful metric of fuel cell performance. This, along with other measures, is then used to generate an âelectro-thermal performance mapâ of fuel cell operation. A commercial air-cooled open-cathode fuel cell is used to demonstrate how the approach can be used; in this case leading to the identification of the optimum operating temperature of âź45 °C
The Hydro-electro-thermal Performance of Air-cooled, Open-cathode Polymer Electrolyte Fuel Cells: Combined Localised Current Density, Temperature and Water Mapping
In situ diagnostic techniques provide a means of understanding the internal workings of fuel cells so that improved designs and operating regimes can be identified. Here, a novel metrology approach is reported that combines current and temperature mapping with water visualisation using neutron radiography.
The approach enables a hydro-electro-thermal performance map to be generated that is applied to an air-cooled, open-cathode polymer electrolyte fuel cell. This type of fuel cell exhibits a particularly interesting coupled relationship between water, current and heat, as the air supply has the due role of cooling the stack as well as providing the cathode reactant feed via a single source. It is found that water predominantly accumulates under the cooling channels (thickness of 70-100 Îźm under the cooling channels and 5-25 Îźm in the active channels at 0.5 A cmâ2), in a similar fashion to the lands in a closed-cathode design, but contrary to passive open-cathode systems. The relationship between current, temperature and water accumulation is complex and highly dependent on location within the cell. However, there is a general trend that higher currents and cooling limitations, especially above 0.7 A cmâ2 and below 3.9 Ă 10â3 m3 sâ1, leads to temperatures above 60 °C, which dehydrate the membrane (water thickness of 10-25 um) and the cell operates below 0.5 V
'Chardonel' Grape
'Chardonel' resulted from the cross, 'SeyvaT x 'Chardonnay,'
made in 1953. Fruit were first observed in 1958, and the
original vine was propagated in 1960 under the number NY
45010. In later testing, it was re-named GW 9 (Geneva White 9)
for ease of identification in cooperatively run yield trials. The
vine was initially described as vigorous and productive with
large clusters
Combined current and temperature mapping in an air-cooled, open-cathode polymer electrolyte fuel cell under steady-state and dynamic conditions
In situ diagnostic techniques provide a means of understanding the internal workings of fuel cells so that improved designs and operating regimes can be identified. Here, for the first time, a combined current density and temperature distributed measurement system is used to generate an electro-thermal performance map of an air-cooled, air-breathing polymer electrolyte fuel cell stack operating in an air/hydrogen cross-flow configuration. Analysis is performed in low- and high-current regimes and a complex relationship between localised current density, temperature and reactant supply is identified that describes the way in which the system enters limiting performance conditions. Spatiotemporal analysis was carried out to characterise transient operations in dead-ended anode/purge mode which revealed extensive current density and temperature gradients
Digitalization and sustainability: a call for a digital green deal
The relation between digitalization and environmental sustainability is ambiguous. There is potential of various digital technologies to slow down the transgression of planetary boundaries. Yet resource and energy demand for digital hardware production and use of data-intensive applications is of substantial size. The world over, there is no comprehensive regulation that addresses opportunities and risks of digital technology for sustainability. In this perspective article, we call for a Digital Green Deal that includes strong, cross-sectoral green digitalization policies on all levels of governance. We argue that a Digital Green Deal should first and foremost aim at greater policy coherence: Current digital policy initiatives should include measures that service environmental goals, and environmental policies must address risks and advance opportunities of digital technologies to spur sustainability transformations
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