Evaluating adjusted forcing and model spread for historical and future scenarios in the CMIP5 generation of climate models

We utilize energy budget diagnostics from the Coupled Model Intercomparison Project phase 5 (CMIP5) to evaluate the models' climate forcing since preindustrial times employing an established regression technique. The climate forcing evaluated this way, termed the adjusted forcing (AF), includes a rapid adjustment term associated with cloud changes and other tropospheric and land-surface changes. We estimate a 2010 total anthropogenic and natural AF from CMIP5 models of 1.9 ± 0.9 W m−2 (5–95% range). The projected AF of the Representative Concentration Pathway simulations are lower than their expected radiative forcing (RF) in 2095 but agree well with efficacy weighted forcings from integrated assessment models. The smaller AF, compared to RF, is likely due to cloud adjustment. Multimodel time series of temperature change and AF from 1850 to 2100 have large intermodel spreads throughout the period. The intermodel spread of temperature change is principally driven by forcing differences in the present day and climate feedback differences in 2095, although forcing differences are still important for model spread at 2095. We find no significant relationship between the equilibrium climate sensitivity (ECS) of a model and its 2003 AF, in contrast to that found in older models where higher ECS models generally had less forcing. Given the large present-day model spread, there is no indication of any tendency by modelling groups to adjust their aerosol forcing in order to produce observed trends. Instead, some CMIP5 models have a relatively large positive forcing and overestimate the observed temperature change.

The Syntax of Pronominal Subjects in L2 Spanish: Comparing Two L2 Populations with Different Exposure

The purpose of this article is two-fold. First, via a critical review of available studies on the adult L2 resetting of the Null-Subject Parameter (NSP) and in light of a typologically wide sampling of languages, we conclude that the NSP cluster is much narrower in scope than is reflected in the design and discussion of most L2 studies. Secondly, we present original research on the L2 resetting of the NSP by two groups of adult English intermediate learners of L2 Spanish: a study-abroad group and a class-room only group. We seek to quantify the extent to which study-abroad experience, that is, increased exposure to native input, is beneficial specifically as it relates to the acquisition of new functional features needed for parameter re-setting (cf. Isabelli 2004). Despite the observable and clandestine linguistic benefits to study-abroad, our data suggest that for the resetting of the NSP, at least, such exposure to native input is not particularly gainful.

Contribution to collective harms and responsibility

In the present contribution, I discuss the claim, endorsed by a number of authors, that contributing to a collective harm is the ground for special responsibilities to the victims of that harm. Contributors should, between them, cover the costs of the harms they have inflicted, at least if those harms would otherwise be rights-violating. I raise some doubts about the generality of this principle before moving on to sketch a framework for thinking about liability for the costs of harms in general. This framework uses a contractualist framework to build an account of how to think about liability for costs on the basis of the presumably attractive thought that individual agents should have as much control over their liabilities as is compatible with others having like control. I then use that framework to suggest that liability on the basis of contribution should be restricted to cases in which the contributors could have avoided their contribution relatively costlessly, in which meeting the liability is not crippling for them, and in which such a liability would not have chilling effects, either on them or on third parties. This account of the grounds for contributory liability also has the advantage of avoiding a number of awkward questions about what counts as a contribution by shifting the issue away from often unanswerable questions about the precise causal genesis of some harm or other. Instead, control over conduct, which plausibly has some relation to the harm, becomes crucial. On the basis of this account, I then investigate whether a number of uses of the contributory principle are entirely appropriate. I argue that contributory liability is not appropriate for cases of collective harms committed by coordinated groups in the way that, for example, Iris Marion Young and Thomas Pogge have suggested and that further investigation of how members of such groups may be liable will be needed.

Argument structures in Chinese university students’ argumentative writing: a contrastive study

Situated within a Systemic Functional Linguistics genre paradigm, this study adopted a function-based linguistic approach to examine the argument structures in English writing produced by Chinese university students of English as foreign language (EFL). Their English writing was contrasted with three other sets of argumentative essays in order to explore differences and similarities in the use of argument structures. The four sets of essays were produced by three groups of university students: native English- and Chinese-speaking university students and Chinese university EFL students. Participants’ interviews and questionnaire responses were also collected. The study found that most native English-speaking participants used an analytical arguing strategy, while most Chinese-speaking university participants preferred a hortatory argument structure both in their English and Chinese writing. It was also found that Chinese participants’ English writing was influenced by both English and Chinese.

Using problem-based learning in a chemistry practical class for pharmacy students and engaging them with feedback

Objective: To introduce a new approach to problem based learning (PBL) used in the context of medicinal chemistry practical class teaching pharmacy students. Design: The described chemistry practical is based on independent studies by small groups of undergraduate students (4-5), who design their own practical work taking relevant professional standards into account. Students are carefully guided by feedback and acquire a set of skills important to their future profession as healthcare professionals. This model has been tailored to the application of PBL in a chemistry practical class setting for a large student cohort (150 students). Assessment: The achievement of learning outcomes is based on the submission of relevant documentation including a certificate of analysis, in addition to peer assessment. Some of the learning outcomes are also assessed in the final written examination at the end of the academic year. Conclusion: The described design of a novel PBL chemistry laboratory course for pharmacy students has been found to be successful. Self-reflective learning and engagement with feedback were encouraged, and students enjoyed the challenging learning experience. Skills that are highly essential for the students’ future careers as healthcare professionals are promoted.

Strangely dual orbifold equivalence I

In this brief note we prove orbifold equivalence between two potentials described by strangely dual exceptional unimodular singularities of type K14 and Q10 in two different ways. The matrix factorizations proving the orbifold equivalence give rise to equations whose solutions are permuted by Galois groups which differ for different expressions of the same singularity.

The role of protecting groups in the formation of organogels through a nano-fibrillar network formed by self-assembling terminally protected tripeptides

A series of eight synthetic self-assembling terminally blocked tripeptides have been studied for gelation. Some of them form gels in various aromatic solvents including benzene, toluene, xylene, and chlorobenzene. It has been found that the protecting groups play an important role in the formation of organogels. It has been observed that, if the C-terminal has been changed from methyl ester to ethyl ester the gelation property does not change significantly (keeping the N-terminal protecting group same), while the change of the protecting group from ethyl ester to isopropyl ester completely abolishes the gelation property. Similarly, keeping the identical C-terminal protecting group (methyl ester) the results of the gelation study indicate that the substitution of N-terminal protection Boc-(tert-butyloxycarbonyl) to Cbz-(benzyloxycarbonyl) does change the gelation property insignificantly, while the change from Boc- to pivaloyl (Piv-) or acetyl (Ac-) group completely eliminates the gelation property. Morphological studies of the dried gels of two of the peptides indicate the presence of an entangled nano-fibrillar network that might be responsible for gelation. FTIR studies of the gels demonstrate that an intermolecular hydrogen bonding network is formed during gelation. Results of X-ray powder diffraction studies for these gelator peptides in different states (dried gels, gel, and bulk solids) reflected that the structure in the wet gel is distinctly different from the dried gel and solid state structures. Single crystal X-ray diffraction studies of a non-gelator peptide, which is structurally similar to the gelator molecules reveal that the peptide forms an antiparallel beta-sheet structure in crystals. (c) 2007 Elsevier Ltd. All rights reserved.

The influence of pomegranate by-product and punicalagins on selected groups of human intestinal microbiota.

We have examined the gut bacterial metabolism of pomegranate by-product (POMx) and major pomegranate polyphenols, punicalagins, using pH-controlled, stirred, batch culture fermentation systems reflective of the distal region of the human large intestine. Incubation of POMx or punicalagins with faecal bacteria resulted in formation of the dibenzopyranone-type urolithins. The time course profile confirmed the tetrahydroxylated urolithin D as the first product of microbial transformation, followed by compounds with decreasing number of phenolic hydroxy groups: the trihydroxy analogue urolithin C and dihydroxylated urolithin A. POMx exposure enhanced the growth of total bacteria, Bifidobacterium spp. and Lactobacillus spp., without influencing the Clostridium coccoides–Eubacterium rectale group and the C. histolyticum group. In addition, POMx increased concentrations of short chain fatty acids (SCFA) viz. acetate, propionate and butyrate in the fermentation medium. Punicalagins did not affect the growth of bacteria or production of SCFA. The results suggest that POMx oligomers, composed of gallic acid, ellagic acid and glucose units, may account for the enhanced growth of probiotic bacteria.

In vitro fermentation of a red wine extract by human gut microbiota: changes in microbial groups and formation of phenolic metabolites

An in vitro batch culture fermentation experiment was conducted with fecal inocula from three healthy volunteers in the presence and absence of a red wine extract. Changes in main bacterial groups were determined by FISH during a 48 h fermentation period. The catabolism of main flavonoids (i.e., flavan-3-ols and anthocyanins) and the formation of a wide a range of phenolic microbial metabolites were determined by a targeted UPLC-PAD-ESI-TQ MS method. Statistical analysis revealed that catechol/pyrocatechol, as well as 4-hydroxy-5-(phenyl)-valeric, 3- and 4-hydroxyphenylacetic, phenylacetic, phenylpropionic, and benzoic acids, showed the greatest increases in concentration during fermentation, whereas 5-(3′-hydroxyphenyl)-γ-valerolactone, its open form 4-hydroxy-5-(3′-hydroxyphenyl)-valeric acid, and 3,4-dihydroxyphenylacetic acid represented the largest interindividual variations in the catabolism of red wine polyphenols. Despite these changes, microbial catabolism did not produce significant changes in the main bacterial groups detected, although a slight inhibition of the Clostridium histolyticum group was observed.

In vitro fermentation of grape seed flavan-3-ol fractions by human faecal microbiota: changes in microbial groups and phenolic metabolites

With the aim of investigating the potential of flavan-3-ols to influence the growth of intestinal bacterial groups, we have carried out the in vitro fermentation, with human faecal microbiota, of two purified fractions from grape seed extract (GSE): GSE-M (70% monomers and 28% procyanidins) and GSE-O (21% monomers and 78 % procyanidins). Samples were collected at 0, 5, 10, 24, 30 and 48 h of fermentation for bacterial enumeration by fluorescent in situ hybridization and for analysis of phenolic metabolites. Both GSE-M and GSE-O fractions promoted growth of Lactobacillus/Enterococcus and decrease in the Clostridium histolyticum group during fermentation, although the effects were only statistically significant with GSE-M for Lactobacillus/Enterococcus (at 5 and 10 h of fermentation) and GSE-O for C. histolyticum (at 10 h of fermentation). Main changes in polyphenol catabolism also occurred during the first 10 h of fermentation, however no significant correlation coefficients (P>0.05) were found between changes in microbial populations and precursor flavan-3-ols or microbial metabolites. Together these data suggest that the flavan-3-ol profile of a particular food source could affect the microbiota composition and its catabolic activity, inducing changes that could in turn affect the bioavailability and potential bioactivity of these compounds.

Mutual binding of polymer end-groups by complementary π–π-stacking: a molecular “Roman Handshake”

Self-complementary tweezer-molecules based on a naphthalenediimide core self-assemble into supramolecular dimers through mutual π–π-stacking and hydrogen bonding. The resulting motif is extremely stable in solution (Ka = 105 M−1), and its attachment to one terminal position of a poly(ethylene glycol) chain leads to a doubling of the polymer's apparent molecular weight.

Determination of orientations of aromatic groups in self-assembled peptide fibrils by polarised Raman spectroscopy

In this paper we describe a novel combination of Raman spectroscopy, isotope editing and X-ray scattering as a powerful approach to give detailed structural information on aromatic side chains in peptide fibrils. The orientation of the tyrosine residues in fibrils of the peptide YTIAALLSPYS with respect to the fibril axis has been determined from a combination of polarised Raman spectroscopy and X-ray diffraction measurements. The Raman intensity of selected tyrosine bands collected at different polarisation geometries is related to the values and orientation of the Raman tensor for those specific vibrations. Using published Raman tensor values we solved the relevant expressions for both of the two tyrosine residues present in this peptide. Ring deuteration in one of the two tyrosine side chains allowed for the calculation to be performed individually for both, by virtue of the isotopic shift that eliminates band overlapping. Sample disorder was taken into account by obtaining the distribution of orientations of the samples from X-ray diffraction experiments. The results provide previously unavailable details about the molecular conformation of this peptide, and demonstrate the value of this approach for the study of amyloid fibrils.