157 research outputs found
Detection and distribution of Craspedacusta sowerbii: Observations of medusae are not enough
The freshwater cnidarian Craspedacusta sowerbii, native to the Yangtze valley, has invaded lakes and ponds throughout the world. Most distribution records have to date been based on observations of the medusa (jellyfish) stage, including numerous recent publications. We aimed to determine whether polyps are widespread in lakes, and geographical areas, outside of where medusae have been observed, and whether constructed waters are more easily invaded than natural waters. Our results show that C. sowerbii is more common and widespread than is apparent from observations of medusae. We argue that observed occurrences of medusae provide little useful information regarding the distribution of this species, and that published records of new jellyfish occurrences provide unreliable estimates of the timing of introduction, establishment or spread of C. sowerbii in new regions. We found no evidence that constructed waters were more readily invaded than natural waters. Overall, accurate determination of Craspedacusta occurrence and distribution requires systematic surveys of the polyp stages
Pollution of soils by lead and its uptake and pathways in the ecosystem.
The thesis reviews literature relating to lead in the environment with particular reference to the distribution and pathways of lead in the soil and plant ecosystem. Methods of conducting large area soil surveys and assessing the distribution of lead and other heavy metals including cadmium, copper and zinc are also examined. A survey was conducted over a 370 km2 area of North East Derbyshire, England. Maps showing the distribution of the metals reveal anomalously high concentrations related in many instances to past industrial activity. A simple reliable and rapid acid digestion procedure was developed and the procedure evaluated through an interlaboratory survey involving 22 laboratories. This demonstrated that analysts should seek to improve analytical performance through achieving better interlaboratory correlation rather than intralaboratory precision. A stratified random sampling protocol was developed and evaluated which allowed an estimate of precision to be placed on the results of the trace metal soil survey. An assessment was carried out of the contribution that lead fromaerially deposited dust and soil sources makes to the distribution of lead in potato plants. A micro sampling cup technique was developed which permitted (for the first time as far as can be ascertained) the analysis of lead in discrete sections of solid plant tissue from single plants grown under field conditions. This overcomes the problems of sensitivity which normally requires that samples are bulked or dosed with lead salts. Results are presented for the distribution of lead in potato plants grown in several field locations and in soils containing varying concentrations of lead. The major source of lead in the plants via the soil with aerial sources having a negligible effect on tissue distribution. Comparisons are made between results obtained by conventional flame atomic absorption spectrometry and the microsampling cup procedure
Source-Free Adaptation to Measurement Shift via Bottom-Up Feature Restoration
Source-free domain adaptation (SFDA) aims to adapt a model trained on
labelled data in a source domain to unlabelled data in a target domain without
access to the source-domain data during adaptation. Existing methods for SFDA
leverage entropy-minimization techniques which: (i) apply only to
classification; (ii) destroy model calibration; and (iii) rely on the source
model achieving a good level of feature-space class-separation in the target
domain. We address these issues for a particularly pervasive type of domain
shift called measurement shift which can be resolved by restoring the source
features rather than extracting new ones. In particular, we propose Feature
Restoration (FR) wherein we: (i) store a lightweight and flexible approximation
of the feature distribution under the source data; and (ii) adapt the
feature-extractor such that the approximate feature distribution under the
target data realigns with that saved on the source. We additionally propose a
bottom-up training scheme which boosts performance, which we call Bottom-Up
Feature Restoration (BUFR). On real and synthetic data, we demonstrate that
BUFR outperforms existing SFDA methods in terms of accuracy, calibration, and
data efficiency, while being less reliant on the performance of the source
model in the target domain.Comment: ICLR 2022 (Spotlight
Ethnic disparities in initiation and intensification of diabetes treatment in adults with type 2 diabetes in the UK, 1990-2017: A cohort study.
BACKGROUND: Type 2 diabetes mellitus (T2DM) disproportionately affects individuals of nonwhite ethnic origin. Timely and appropriate initiation and intensification of glucose-lowering therapy is key to reducing the risk of major vascular outcomes. Given that ethnic inequalities in outcomes may stem from differences in therapeutic management, the aim of this study was to identify ethnic differences in the timeliness of initiation and intensification of glucose-lowering therapy in individuals newly diagnosed with T2DM in the United Kingdom. METHODS AND FINDINGS: An observational cohort study using the Clinical Practice Research Datalink was conducted using 162,238 adults aged 18 and over diagnosed with T2DM between 1990 and 2017 (mean age 62.7 years, 55.2% male); 93% were of white ethnicity (n = 150,754), 5% were South Asian (n = 8,139), and 2.1% were black (n = 3,345). Ethnic differences in time to initiation and intensification of diabetes treatment were estimated at three time points (initiation of noninsulin monotherapy, intensification to noninsulin combination therapy, and intensification to insulin therapy) using multivariable Cox proportional hazards regression adjusted for factors a priori hypothesised to be associated with initiation and intensification: age, sex, deprivation, glycated haemoglobin (HbA1c), body mass index (BMI), smoking status, comorbidities, consultations, medications, calendar year, and clustering by practice. Odds of experiencing therapeutic inertia (failure to intensify treatment within 12 months of HbA1c >7.5% [58 mmol/mol]), were estimated using multivariable logistic regression adjusted for the same hypothesised confounders. Noninsulin monotherapy was initiated earlier in South Asian and black groups (South Asian HR 1.21, 95% CI 1.08-1.36, p < 0.001; black HR 1.29, 95% CI 1.05-1.59, p = 0.017). Correspondingly, no ethnic differences in therapeutic inertia were evident at initiation. Intensification with noninsulin combination therapy was slower in both nonwhite ethnic groups relative to white (South Asian HR 0.80, 95% CI 0.74-0.87, p < 0.001; black HR 0.79, 95% CI 0.70-0.90, p < 0.001); treatment inertia at this stage was greater in nonwhite groups relative to white (South Asian odds ratio [OR] 1.45, 95% CI 1.23-1.70, p < 0.001; black OR 1.43, 95% CI 1.09-1.87, p = 0.010). Intensification to insulin therapy was slower again for black groups relative to white groups (South Asian HR 0.49, 95% CI 0.41-0.58, p < 0.001; black HR 0.69, 95% CI 0.53-0.89, p = 0.012); correspondingly, treatment inertia was significantly higher in nonwhite groups at this stage relative to white groups (South Asian OR 2.68, 95% CI 1.89-3.80 p < 0.001; black OR 1.82, 95% CI 1.13-2.79, p = 0.013). At both stages of treatment intensification, nonwhite groups had fewer HbA1c measurements than white groups. Limitations included variable quality and completeness of routinely recorded data and a lack of information on medication adherence. CONCLUSIONS: In this large UK cohort, we found persuasive evidence that South Asian and black groups intensified to noninsulin combination therapy and insulin therapy more slowly than white groups and experienced greater therapeutic inertia following identification of uncontrolled HbA1c. Reasons for delays are multifactorial and may, in part, be related to poorer long-term monitoring of risk factors in nonwhite groups. Initiatives to improve timely and appropriate intensification of diabetes treatment are key to reducing disparities in downstream vascular outcomes in these populations
Immune function during early adolescence positively predicts adult facial sexual dimorphism in both men and women
Evolutionary theories suggest that humans prefer sexual dimorphism in faces because masculinity in men and femininity in women may be an indicator of immune function during development. In particular, the immunocompetence handicap hypothesis proposes that sexual dimorphism indicates good immune function during development because the sex hormones, particularly testosterone in men, required for the development of sexually dimorphic facial features also taxes the immune system. Therefore, only healthy males can afford the high level of testosterone for the development of sexually dimorphic traits without compromising their survival. Researchers have suggested that a similar mechanism via the effects of oestrogen might also explain male preferences for female femininity. Despite the prominence of the immunocompetence handicap hypothesis, no studies have tested whether immune function during development predicts adult facial sexual dimorphism. Here, using data from a longitudinal public health dataset, the Western Australian Pregnancy Cohort (Raine) Study (Generation 2), we show that some aspects of immune function during early adolescence (14 years) positively predict sexually dimorphic 3D face shape in both men and women. Our results support a fundamental assumption that facial sexual dimorphism is an indicator of immune function during the development of facial sexual dimorphism.PostprintPeer reviewe
New calibration techniques for the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS)
Recent laboratory calibrations of the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) include new methods for the characterization of the geometric, spectral, temporal and radiometric properties of the sensor. New techniques are desired in order to: (1) increase measurement accuracy and precision, (2) minimize measurement time and expense, (3) prototype new field and inflight calibration systems, (4) resolve measurement ambiguities, and (5) add new measurement dimensions. One of the common features of these new methods is the use of the full data collection and processing power of the AVIRIS instrument and data facility. This allows the collection of large amounts of calibration data in a short period of time and is well suited to modular data analysis routines
Effects of acute alcohol consumption on emotion recognition in high and low trait aggressive drinkers
Background: Research suggests that acute alcohol consumption impairs processing of emotional faces. As emotion processing plays a key role in effective social interaction, these impairments may be one mechanism by which alcohol changes social behaviour. This study investigated the effect of individual differences on this relationship by comparing emotion recognition performance after acute alcohol consumption in individuals with high and low trait aggression. Methods: Regular non-dependent drinkers, either high or low in trait aggression participated in a double-blind placebo-controlled experiment (N = 88, 50% high trait aggressive). Participants attended two sessions. In one they consumed an alcoholic drink (0.4 g/kg) and in the other they consumed a matched placebo. They then completed two computer-based tasks: one measured global and emotion-specific recognition performance across six primary emotions (anger, sadness, happiness, disgust, fear, surprise), the other measured processing bias of two ambiguously expressive faces (happy–angry/happy–sad). Results: There was evidence of poorer global emotion recognition after alcohol. In addition, there was evidence of poorer sensitivity to sadness and fear after alcohol. There was also evidence for a reduced bias towards happiness following alcohol and weak evidence for an increased bias towards sadness. Conclusions: These findings suggest that alcohol impairs global emotion recognition. They also highlight a reduced ability to detect sadness and fearful facial expressions. As sadness and fear are cues of submission and distress (i.e. function to curtail aggression), failure to successfully detect these emotions when intoxicated may increase the likelihood of aggressive responding. This coupled with a reduced bias towards seeing happiness may collectively contribute to aggressive behaviour
Understanding Precatalyst Activation and Speciation in Manganese-Catalyzed C-H Bond Functionalization Reactions
An investigation into species formed following precatalyst activation in Mn-catalyzed C-H bond functionalization reactions is reported. Time-resolved infrared spectroscopy demonstrates that light-induced CO dissociation from precatalysts [Mn(C^N)(CO)4] (C^N = cyclometalated 2-phenylpyridine (1a), cyclometalated 1,1-bis(4-methoxyphenyl)methanimine (1b)) in a toluene solution of 2-phenylpyridine (2a) or 1,1-bis(4-methoxyphenyl)methanimine (2b) results in the initial formation of solvent complexes fac-[Mn(C^N)(CO)3(toluene)]. Subsequent solvent substitution on a nanosecond time scale then yields fac-[Mn(C^N)(CO)3(κ1-(N)-2a)] and fac-[Mn(C^N)(CO)3(κ1-(N)-2b)], respectively. When the experiments are performed in the presence of phenylacetylene, the initial formation of fac-[Mn(C^N)(CO)3(toluene)] is followed by a competitive substitution reaction to give fac-[Mn(C^N)(CO)3(2)] and fac-[Mn(C^N)(CO)3(η2-PhC2H)]. The fate of the reaction mixture depends on the nature of the nitrogen-containing substrate used. In the case of 2-phenylpyridine, migratory insertion of the alkyne into the Mn-C bond occurs, and fac-[Mn(C^N)(CO)3(κ1-(N)-2a)] remains unchanged. In contrast, when 2b is used, substitution of the η2-bound phenylacetylene by 2b occurs on a microsecond time scale, and fac-[Mn(C^N)(CO)3(κ1-(N)-2b)] is the sole product from the reaction. Calculations with density functional theory indicate that this difference in behavior may be correlated with the different affinities of 2a and 2b for the manganese. This study therefore demonstrates that speciation immediately following precatalyst activation is a kinetically controlled event. The most dominant species in the reaction mixture (the solvent) initially binds to the metal. The subsequent substitution of the metal-bound solvent is also kinetically controlled (on a ns time scale) prior to the thermodynamic distribution of products being obtained
Trilostane in dogs
Over the last 10 years, trilostane, a competitive inhibitor of steroid synthesis, is being widely used for the treatment of canine hyperadrenocorticism. Trilostane causes a significant but reversible decrease in cortisol production and a concomitant improvement in clinical signs in most dogs with this common condition. Side effects, though infrequent, can be serious: dogs treated with this drug require regular monitoring. This review summarizes current knowledge of the use of this drug with particular emphasis on its efficacy, safety, adverse reactions, and effects on endocrine parameters. Brief mention is made of its other uses in dogs and other species
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