Morphological characteristics of ant assemblages (Hymenoptera: Formicidae) differ among contrasting biomes

The environment is thought to strongly shape the ecology and evolution of species. Similar environments may cause species to look the same or converge upon particular traits. Dissimilar environments can cause species to look different or to diverge in their traits. These ideas have been explored at the single species level or within restricted geographic areas for ants. We ask whether the signature of environmental filtering can be detected within ant faunas at the biogeographic scale. We quantify differences in the morphological traits of ant faunas between two contrasting biomes: a rainforest in Costa Rica and a desert in Iran. Lists of species from each habitat type were compiled, and measurements of ten functional traits were taken from scaled images. Body size, relative femur length, and tibia length were significantly smaller in Costa Rica suggesting species in more complex environments are smaller in response to environmental complexity. Relative eye width was also smaller in Costa Rica, and individuals were lighter in colour. Eye size and body pigmentation showed differences which may be a result of altered foraging patterns or protection against UV-B irradiance. The Costa Rican fauna also had a much wider trait space (higher functional richness), and Iranian species occupied a narrow range in terms of mandible and leg size suggesting species invest less in foraging specialism in unproductive environments. Significant differences in morphological traits and their degree of overlap can therefore be observed in ant faunas occupying contrasting biomes. We suggest that this is due to the environment influencing the trait composition of these faunas at biogeographic scales

Structural, spectroscopic, and computational evaluations of cation-cation and halogen bonding interactions in heterometallic uranyl hybrid materials

Harnessing the nominally terminal oxo atoms of the linear uranyl (UO22+) cation represents a frontier within the field of f-element hybrid materials. Here we outline a route for systematically accessing uranyl oxo atoms via judicious pairing with Ag+ cations or iodobenzoates, and describe the syntheses and crystal structures of four new heterometallic compounds containing Ag+ cations, the UO22+ cation, and o- (1), m- (2), p-iodo- (3), and 2,5-diiodo- (4) carboxylate ligands. Vibrational and luminescence spectroscopic properties for all four compounds are reported, as are computational findings from quantum chemical calculations and density-based quantum theory of atoms in molecules (QTAIM) analyses. Single crystal X-ray diffraction analysis of compounds 1-4 shows that the nominally terminal uranyl oxo atoms are engaged in either covalent UO2-Ag cation-cation interactions (1 and 3) or non-covalent assembly via halogen bonding interactions (2 and 4). Raman, infrared (IR), and luminescence spectra of 1-4 are redshifted with respect to the free uranyl cation indicating that both halogen-oxo and cation-cation interactions weaken the UO bond, and in the case of 3 we note a rare example of activation of the uranyl asymmetric stretch (ν3) in the Raman spectra, likely due to the Ag-oxo cation-cation interaction lowering the symmetry of the uranyl cation. Quantum chemical calculations and QTAIM analysis highlight a quantitative difference between halogen bonds and cation-cation interactions, with the latter shown to significantly decrease uranyl bond orders and electron density at bond critical points

Intravenous versus inhalational maintenance of anaesthesia for postoperative cognitive outcomes in elderly people undergoing non-cardiac surgery

Background: The use of anaesthetics in the elderly surgical population (more than 60 years of age) is increasing. Postoperative delirium, an acute condition characterized by reduced awareness of the environment and a disturbance in attention, typically occurs between 24 and 72 hours after surgery and can affect up to 60% of elderly surgical patients. Postoperative cognitive dysfunction (POCD) is a new-onset of cognitive impairment which may persist for weeks or months after surgery. Traditionally, surgical anaesthesia has been maintained with inhalational agents. End-tidal concentrations require adjustment to balance the risks of accidental awareness and excessive dosing in elderly people. As an alternative, propofol-based total intravenous anaesthesia (TIVA) offers a more rapid recovery and reduces postoperative nausea and vomiting. Using TIVA with a target controlled infusion (TCI) allows plasma and effect-site concentrations to be calculated using an algorithm based on age, gender, weight and height of the patient. TIVA is a viable alternative to inhalational maintenance agents for surgical anaesthesia in elderly people. However, in terms of postoperative cognitive outcomes, the optimal technique is unknown. Objectives: To compare maintenance of general anaesthesia for elderly people undergoing non-cardiac surgery using propofol-based TIVA or inhalational anaesthesia on postoperative cognitive function, mortality, risk of hypotension, length of stay in the postanaesthesia care unit (PACU), and hospital stay. Search methods: We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 11), MEDLINE (1946 to November 2017), Embase (1974 to November 2017), PsycINFO (1887 to November 2017). We searched clinical trials registers for ongoing studies, and conducted backward and forward citation searching of relevant articles. Selection criteria: We included randomized controlled trials (RCTs) with participants over 60 years of age scheduled for non-cardiac surgery under general anaesthesia. We planned to also include quasi-randomized trials. We compared maintenance of anaesthesia with propofol-based TIVA versus inhalational maintenance of anaesthesia. Data collection and analysis: Two review authors independently assessed studies for inclusion, extracted data, assessed risk of bias, and synthesized findings. Main results: We included 28 RCTs with 4507 randomized participants undergoing different types of surgery (predominantly cardiovascular, laparoscopic, abdominal, orthopaedic and ophthalmic procedures). We found no quasi-randomized trials. Four studies are awaiting classification because we had insufficient information to assess eligibility. All studies compared maintenance with propofol-based TIVA versus inhalational maintenance of anaesthesia. Six studies were multi-arm and included additional TIVA groups, additional inhalational maintenance or both. Inhalational maintenance agents included sevoflurane (19 studies), isoflurane (eight studies), and desflurane (three studies), and was not specified in one study (reported as an abstract). Some studies also reported use of epidural analgesia/anaesthesia, fentanyl and remifentanil. We found insufficient reporting of randomization methods in many studies and all studies were at high risk of performance bias because it was not feasible to blind anaesthetists to study groups. Thirteen studies described blinding of outcome assessors. Three studies had a high of risk of attrition bias, and we noted differences in the use of analgesics between groups in six studies, and differences in baseline characteristics in five studies. Few studies reported clinical trials registration, which prevented assessment of risk of selective reporting bias. We found no evidence of a difference in incidences of postoperative delirium according to type of anaesthetic maintenance agents (odds ratio (OR) 0.59, 95% confidence interval (CI) 0.15 to 2.26; 321 participants; five studies; very low-certainty evidence); we noted during sensitivity analysis that using different time points in one study may influence direction of this result. Thirteen studies (3215 participants) reported POCD, and of these, six studies reported data that could not be pooled; we noted no difference in scores of POCD in four of these and in one study, data were at a time point incomparable to other studies. We excluded one large study from meta-analysis because study investigators had used non-standard anaesthetic management and this study was not methodologically comparable to other studies. We combined data for seven studies and found low-certainty evidence that TIVA may reduce POCD (OR 0.52, 95% CI 0.31 to 0.87; 869 participants). We found no evidence of a difference in mortality at 30 days (OR 1.21, 95% CI 0.33 to 4.45; 271 participants; three studies; very low-certainty evidence). Twelve studies reported intraoperative hypotension. We did not perform meta-analysis for 11 studies for this outcome. We noted visual inconsistencies in these data, which may be explained by possible variation in clinical management and medication used to manage hypotension in each study (downgraded to low-certainty evidence); one study reported data in a format that could not be combined and we noted little or no difference between groups in intraoperative hypotension for this study. Eight studies reported length of stay in the PACU, and we did not perform meta-analysis for seven studies. We noted visual inconsistencies in these data, which may be explained by possible differences in definition of time points for this outcome (downgraded to very low-certainty evidence); data were unclearly reported in one study. We found no evidence of a difference in length of hospital stay according to type of anaesthetic maintenance agent (mean difference (MD) 0 days, 95% CI -1.32 to 1.32; 175 participants; four studies; very low-certainty evidence). We used the GRADE approach to downgrade the certainty of the evidence for each outcome. Reasons for downgrading included: study limitations, because some included studies insufficiently reported randomization methods, had high attrition bias, or high risk of selective reporting bias; imprecision, because we found few studies; inconsistency, because we noted heterogeneity across studies. Authors' conclusions: We are uncertain whether maintenance with propofol-based TIVA or with inhalational agents affect incidences of postoperative delirium, mortality, or length of hospital stay because certainty of the evidence was very low. We found low-certainty evidence that maintenance with propofol-based TIVA may reduce POCD. We were unable to perform meta-analysis for intraoperative hypotension or length of stay in the PACU because of heterogeneity between studies. We identified 11 ongoing studies from clinical trials register searches; inclusion of these studies in future review updates may provide more certainty for the review outcomes. © 2018 The Cochrane Collaboration

A New Mechanism for β‐Lactamases: Class D Enzymes Degrade 1β‐Methyl Carbapenems through Lactone Formation

β‐Lactamases threaten the clinical use of carbapenems, which are considered antibiotics of last resort. The classical mechanism of serine carbapenemase catalysis proceeds through hydrolysis of an acyl‐enzyme intermediate. We show that class D β‐lactamases also degrade clinically used 1β‐methyl‐substituted carbapenems through the unprecedented formation of a carbapenem‐derived β‐lactone. β‐Lactone formation results from nucleophilic attack of the carbapenem hydroxyethyl side chain on the ester carbonyl of the acyl‐enzyme intermediate. The carbapenem‐derived lactone products inhibit both serine β‐lactamases (particularly class D) and metallo‐β‐lactamases. These results define a new mechanism for the class D carbapenemases, in which a hydrolytic water molecule is not required.FWN – Publicaties zonder aanstelling Universiteit Leide

A New Mechanism for β‐Lactamases: Class D Enzymes Degrade 1β‐Methyl Carbapenems through Lactone Formation

β‐Lactamases threaten the clinical use of carbapenems, which are considered antibiotics of last resort. The classical mechanism of serine carbapenemase catalysis proceeds through hydrolysis of an acyl‐enzyme intermediate. We show that class D β‐lactamases also degrade clinically used 1β‐methyl‐substituted carbapenems through the unprecedented formation of a carbapenem‐derived β‐lactone. β‐Lactone formation results from nucleophilic attack of the carbapenem hydroxyethyl side chain on the ester carbonyl of the acyl‐enzyme intermediate. The carbapenem‐derived lactone products inhibit both serine β‐lactamases (particularly class D) and metallo‐β‐lactamases. These results define a new mechanism for the class D carbapenemases, in which a hydrolytic water molecule is not required.FWN – Publicaties zonder aanstelling Universiteit Leide

Women, men and coronary heart disease: a review of the qualitative literature

Aim. This paper presents a review of the qualitative literature which examines the experiences of patients with coronary heart disease. The paper also assesses whether the experiences of both female and male patients are reflected in the literature and summarizes key themes. Background. Understanding patients' experiences of their illness is important for coronary heart disease prevention and education. Qualitative methods are particularly suited to eliciting patients' detailed understandings and perceptions of illness. As much previous research has been 'gender neutral', this review pays particular attention to gender. Methods. Published papers from 60 qualitative studies were identified for the review through searches in MEDLINE, EMBASE, CINAHL, PREMEDLINE, PsychINFO, Social Sciences Citation Index and Web of Science using keywords related to coronary heart disease. Findings. Early qualitative studies of patients with coronary heart disease were conducted almost exclusively with men, and tended to generalize from 'male' experience to 'human' experience. By the late 1990s this pattern had changed, with the majority of studies including women and many being conducted with solely female samples. However, many studies that include both male and female coronary heart disease patients still do not have a specific gender focus. Key themes in the literature include interpreting symptoms and seeking help, belief about coronary 'candidates' and relationships with health professionals. The influence of social roles is important: many female patients have difficulties reconciling family responsibilities and medical advice, while male patients worry about being absent from work. Conclusions. There is a need for studies that compare the experiences of men and women. There is also an urgent need for work that takes masculinity and gender roles into account when exploring the experiences of men with coronary heart disease

High-spatial resolution functional chemistry of nitrogen compounds in the observed UK meteorite fall Winchcombe

Organic matter in extraterrestrial samples is a complex material that might have played an important role in the delivery of prebiotic molecules to the early Earth. We report here on the identification of nitrogen-containing compounds such as amino acids and N-heterocycles within the recent observed meteorite fall Winchcombe by high-spatial resolution spectroscopy techniques. Although nitrogen contents of Winchcombe organic matter are low (N/C ~ 1–3%), we were able to detect the presence of these compounds using a low-noise direct electron detector. These biologically relevant molecules have therefore been tentatively found within a fresh, minimally processed meteorite sample by high spatial resolution techniques conserving the overall petrographic context. Carbon functional chemistry investigations show that sizes of aromatic domains are small and that abundances of carboxylic functional groups are low. Our observations demonstrate that Winchcombe represents an important addition to the collection of carbonaceous chondrites and still preserves pristine extraterrestrial organic matter

Decreased body mass index in the preclinical stage of autosomal dominant Alzheimer’s disease

The relationship between body-mass index (BMI) and Alzheimer´s disease (AD) has been extensively investigated. However, BMI alterations in preclinical individuals with autosomal dominant AD (ADAD) have not yet been investigated. We analyzed cross-sectional data from 230 asymptomatic members of families with ADAD participating in the Dominantly Inherited Alzheimer Network (DIAN) study including 120 preclinical mutation carriers (MCs) and 110 asymptomatic non-carriers (NCs). Differences in BMI and their relation with cerebral amyloid load and episodic memory as a function of estimated years to symptom onset (EYO) were analyzed. Preclinical MCs showed significantly lower BMIs compared to NCs, starting 11.2 years before expected symptom onset. However, the BMI curves begun to diverge already at 17.8 years before expected symptom onset. Lower BMI in preclinical MCs was significantly associated with less years before estimated symptom onset, higher global Aβ brain burden, and with lower delayed total recall scores in the logical memory test. The study provides cross-sectional evidence that weight loss starts one to two decades before expected symptom onset of ADAD. Our findings point toward a link between the pathophysiology of ADAD and disturbance of weight control mechanisms. Longitudinal follow-up studies are warranted to investigate BMI changes over time

Variable geometries of connection: Urban digital divides and the uses of Information Technology

This paper proposes a new way of conceptualising urban ‘digital divides’. It focuses on the ways in which Information and Communication Technologies (ICTs) unevenly affect the pace of life within the urban environment. Based on a detailed case study of how ICT s are being used in an affluent and a marginalised neighbourhood in Newcastle-upon-Tyne, the paper suggests that urban digital divides need to be understood as more than uneven patterns of access. They emerge in this work as more than the presence or absence of specific technological artefacts. Rather, it is argued that different styles and speeds of technologically mediated life now work to define urban socio-spatial inequalities. The paper distinguishes between two such key styles and speeds. First, the paper argues that affluent and professional groups now use new media technologies pervasively and continuously as the ‘background’ infrastructure to sustain privileged and intensely distanciated, but time-stressed, lifestyles. Second, more marginalised neighbourhoods tend to be characterised by instrumental and episodic ICT usage patterns which are often collectively organised through strong neighbourhood ties. For the former, mediated networks help orchestrate neighbourhood ties; for the latter it is those neighbourhood ties that enable online access

Field Measurements of Terrestrial and Martian Dust Devils

Surface-based measurements of terrestrial and martian dust devils/convective vortices provided from mobile and stationary platforms are discussed. Imaging of terrestrial dust devils has quantified their rotational and vertical wind speeds, translation speeds, dimensions, dust load, and frequency of occurrence. Imaging of martian dust devils has provided translation speeds and constraints on dimensions, but only limited constraints on vertical motion within a vortex. The longer mission durations on Mars afforded by long operating robotic landers and rovers have provided statistical quantification of vortex occurrence (time-of-sol, and recently seasonal) that has until recently not been a primary outcome of more temporally limited terrestrial dust devil measurement campaigns. Terrestrial measurement campaigns have included a more extensive range of measured vortex parameters (pressure, wind, morphology, etc.) than have martian opportunities, with electric field and direct measure of dust abundance not yet obtained on Mars. No martian robotic mission has yet provided contemporaneous high frequency wind and pressure measurements. Comparison of measured terrestrial and martian dust devil characteristics suggests that martian dust devils are larger and possess faster maximum rotational wind speeds, that the absolute magnitude of the pressure deficit within a terrestrial dust devil is an order of magnitude greater than a martian dust devil, and that the time-of-day variation in vortex frequency is similar. Recent terrestrial investigations have demonstrated the presence of diagnostic dust devil signals within seismic and infrasound measurements; an upcoming Mars robotic mission will obtain similar measurement types