802 research outputs found
Characterization of Vitis vinifera cultivars by random amplified polymorphic DNA markers
Research Not
Convergent evolution of elaborate nests as structural defences in birds
The pendent nests of some weaverbird and icterid species are among the most complex structures built by any animal, but why they have evolved remains to be explained. The precarious attachments and extended entrance tunnels characteristic of these nests are widely speculated to act as structural defences against invasion by nest predators, particularly tree-climbing snakes, but this hypothesis has yet to be systematically tested. We use phylogenetic comparative methods to investigate the relationship between nest structure and developmental period length, a proxy for offspring mortality, in weaverbirds (Ploceidae) and icterids (Icteridae), two bird families in which highly elaborate pendent nests have independently evolved. We find that more elaborate nests, particularly those with entrance tunnels, are associated with longer developmental periods in both families. This finding is robust to potentially confounding effects of body mass, phylogenetic relationships, nest location and latitude. Our results are consistent with the hypothesis that elaborate nest structures in birds can function as structural defences, resulting in lower offspring mortality and slower development. More generally, our findings suggest that constructing complex, protective structures may buffer against environmental hazards, reducing extrinsic mortality and contributing to the evolution of slower life histories in diverse animal lineages, even humans
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Sequence tutor: Conservative fine-tuning of sequence generation models with KL-control
This paper proposes a general method for improving the structure and quality
of sequences generated by a recurrent neural network (RNN), while maintaining
information originally learned from data, as well as sample diversity. An RNN
is first pre-trained on data using maximum likelihood estimation (MLE), and the
probability distribution over the next token in the sequence learned by this
model is treated as a prior policy. Another RNN is then trained using
reinforcement learning (RL) to generate higher-quality outputs that account for
domain-specific incentives while retaining proximity to the prior policy of the
MLE RNN. To formalize this objective, we derive novel off-policy RL methods for
RNNs from KL-control. The effectiveness of the approach is demonstrated on two
applications; 1) generating novel musical melodies, and 2) computational
molecular generation. For both problems, we show that the proposed method
improves the desired properties and structure of the generated sequences, while
maintaining information learned from data
Student teamwork: developing virtual support for team projects
In the 21st century team working increasingly requires online cooperative skills as well as more traditional skills associated with face to face team working. Virtual team working differs from face to face team working in a number of respects, such as interpreting the alternatives to visual cues, adapting to synchronous communication, developing trust and cohesion and cultural interpretations. However, co-located student teams working within higher education can only simulate team working as it might be experienced in organisations today. For example, students can learn from their mistakes in a non-threatening environment, colleagues tend to be established friends and assessing teamwork encourages behaviour such as “free-riding”. Using a prototyping approach, which involves students and tutors, a system has been designed to support learners engaged in team working. This system helps students to achieve to their full potential and appreciate issues surrounding virtual teamwork. The Guardian Agent system enables teams to allocate project tasks and agree ground rules for the team according to individuals’ preferences. Results from four cycles of its use are presented, together with modifications arising from iterations of testing. The results show that students find the system useful in preparing for team working, and have encouraged further development of the system
Entrustable professional activities for residency in general internal medicine: a systematic review.
Entrustable Professional Activities (EPAs) are observable tasks that are regular parts of a physician's daily clinical work. Before being permitted to accomplish these tasks independently, trainees must gain their supervisors' trust. Defining the list of EPAs that should be mastered by the end of a residency is critical to setting clear expectations about autonomous practice.
To collect all the lists of EPAs defined for residencies in general internal medicine and synthesise them into a reference work useful for developing new lists of EPAs or improving existing ones.
This systematic review searched five databases and relevant grey literature using keywords related to EPAs and postgraduate education, from 2005, when the first article on EPAs was published, to April 2022. Inclusion criteria were the availability of an EPAs list and a focus on general internal medicine. Two reviewers independently selected the studies, extracted data and performed a quality assessment using QATSDD and AACODS tools. Mean values and inter-rater reliability were calculated.
The review yielded 3292 records, with 16 articles meeting the inclusion criteria, mostly from North America. Synthesising their 16 lists generated 395 EPAs. The reviewers then inductively categoried those EPAs, 308 of which fell into 6 domains, 14 themes and 24 subthemes. The domains were: (1) care and management of the general adult population (n = 103 EPAs); (2) care and management of patients with specific needs (n = 67); (3) care coordination and communication (n = 52); (4) management and leadership (N = 21); (5) healthcare quality, education, and research (n = 41); and (6) miscellaneous (n = 24). The remaining 87 EPAs were disease-specific and did not fit into this categorisation.
Categorising EPAs created a unique synthesis of the existing lists of EPAs for educating residents in general internal medicine. This synthesis could be used as a reference for anyone tasked with developing new lists of EPAs or improving existing ones
Lower Extremity Amputation Rates in People With Diabetes Mellitus:A Retrospective Population Based Cohort Study in Zwolle Region, The Netherlands
OBJECTIVE: Lower extremity amputations are a major complication of diabetes mellitus (DM). In a previous Dutch study, the incident rate of major amputations was 89.2 per 100 000 person years. The primary aim of this study was to describe the lower extremity amputation rates in people with DM in the Zwolle region, where preventive and curative footcare is organised according to the guidelines of the International Working Group of the Diabetic Foot (IWGDF). The secondary aim was to evaluate outcomes and underlying characteristics of these people.METHODS: This was a retrospective regional population based cohort study. Data from all people with DM treated in primary and secondary care, living in the region Zwolle were collected. All amputations in the period 2017 to 2019 were analysed. Comparisons were made between those with and without an amputation.RESULTS: In the analysis 5 915 people with DM were included, with a mean age of 67.8 (IQR 57.9, 75.9) years. Of those people, 47% were women and the median HbA1c was 53 (IQR 47, 62) mmol/mol. Over the three year study period, a total of 68 amputations were performed in 59 people: 46 minor, 22 major. This translated into an average annual crude amputation incidence rate of non-traumatic major and minor amputations of 41.5 and 86.9 per 100 000 person years among people with diabetes. Compared with those not undergoing amputations, those who underwent an amputation were more often men, older, mainly had T2DM, were treated in secondary care, had higher diastolic blood pressure, worse diabetic footcare profile, longer DM duration and higher HbA1c. At the end of the follow up, 111 people died: 96 (1.6%) without and 15 (25.4%) with amputations (p < .001).CONCLUSIONS: This retrospective study provides detailed insight into the rate of amputations in Dutch people with diabetes in the region Zwolle. Compared with previous Dutch estimates, these data suggest a considerable decrease in major amputation incidence rate.</p
Effect of early vasopressin vs norepinephrine on kidney failure in patients with septic shock. The VANISH Randomized Clinical Trial
IMPORTANCE: Norepinephrine is currently recommended as the first-line vasopressor in septic shock; however, early vasopressin use has been proposed as an alternative. OBJECTIVE: To compare the effect of early vasopressin vs norepinephrine on kidney failure in patients with septic shock. DESIGN, SETTING, AND PARTICIPANTS: A factorial (2×2), double-blind, randomized clinical trial conducted in 18 general adult intensive care units in the United Kingdom between February 2013 and May 2015, enrolling adult patients who had septic shock requiring vasopressors despite fluid resuscitation within a maximum of 6 hours after the onset of shock. INTERVENTIONS: Patients were randomly allocated to vasopressin (titrated up to 0.06 U/min) and hydrocortisone (n = 101), vasopressin and placebo (n = 104), norepinephrine and hydrocortisone (n = 101), or norepinephrine and placebo (n = 103). MAIN OUTCOMES AND MEASURES: The primary outcome was kidney failure-free days during the 28-day period after randomization, measured as (1) the proportion of patients who never developed kidney failure and (2) median number of days alive and free of kidney failure for patients who did not survive, who experienced kidney failure, or both. Rates of renal replacement therapy, mortality, and serious adverse events were secondary outcomes. RESULTS: A total of 409 patients (median age, 66 years; men, 58.2%) were included in the study, with a median time to study drug administration of 3.5 hours after diagnosis of shock. The number of survivors who never developed kidney failure was 94 of 165 patients (57.0%) in the vasopressin group and 93 of 157 patients (59.2%) in the norepinephrine group (difference, -2.3% [95% CI, -13.0% to 8.5%]). The median number of kidney failure-free days for patients who did not survive, who experienced kidney failure, or both was 9 days (interquartile range [IQR], 1 to -24) in the vasopressin group and 13 days (IQR, 1 to -25) in the norepinephrine group (difference, -4 days [95% CI, -11 to 5]). There was less use of renal replacement therapy in the vasopressin group than in the norepinephrine group (25.4% for vasopressin vs 35.3% for norepinephrine; difference, -9.9% [95% CI, -19.3% to -0.6%]). There was no significant difference in mortality rates between groups. In total, 22 of 205 patients (10.7%) had a serious adverse event in the vasopressin group vs 17 of 204 patients (8.3%) in the norepinephrine group (difference, 2.5% [95% CI, -3.3% to 8.2%]). CONCLUSIONS AND RELEVANCE: Among adults with septic shock, the early use of vasopressin compared with norepinephrine did not improve the number of kidney failure-free days. Although these findings do not support the use of vasopressin to replace norepinephrine as initial treatment in this situation, the confidence interval included a potential clinically important benefit for vasopressin, and larger trials may be warranted to assess this further. TRIAL REGISTRATION: clinicaltrials.gov Identifier: ISRCTN 20769191
History of oceanic front development in the New Zealand sector of the Southern Ocean during the Cenozoic--a synthesis
The New Zealand sector of the Southern Ocean (NZSSO) has opened about the Indian-Pacific spreading ridge throughout the Cenozoic. Today the NZSSO is characterised by broad zonal belts of antarctic (cold), subantarctic (cool), and subtropical (warm) surface-water masses separated by prominent oceanic fronts: the Subtropical Front (STF) c. 43deg.S, Subantarctic Front (SAF) c. 50deg.S, and Antarctic Polar Front (AAPF) c. 60deg.S. Despite a meagre database, the broad pattern of Cenozoic evolution of these fronts is reviewed from the results of Deep Sea Drilling Project-based studies of sediment facies, microfossil assemblages and diversity, and stable isotope records, as well as from evidence in onland New Zealand Cenozoic sequences. Results are depicted schematically on seven paleogeographic maps covering the NZSSO at 10 m.y. intervals through the Cenozoic.
During the Paleocene and most of the Eocene (65-35 Ma), the entire NZSSO was under the influence of warm to cool subtropical waters, with no detectable oceanic fronts. In the latest Eocene (c. 35 Ma), a proto-STF is shown separating subantarctic and subtropical waters offshore from Antarctica, near 65deg.S paleolatitude. During the earliest Oligocene, this front was displaced northwards by development of an AAPF following major global cooling and biotic turnover associated with ice sheet expansion to sea level on East Antarctica. Early Oligocene full opening (c. 31 Ma) of the Tasmanian gateway initiated vigorous proto-circum-Antarctic flow of cold/cool waters, possibly through a West Antarctic seaway linking the southern Pacific and Atlantic Oceans, including detached northwards "jetting" onto the New Zealand plateau where condensation and unconformity development was widespread in cool-water carbonate facies. Since this time, a broad tripartite division of antarctic, subantarctic, and subtropical waters has existed in the NZSSO, including possible development of a proto-SAF within the subantarctic belt. In the Early-early Middle Miocene (25-15 Ma), warm subtropical waters expanded southwards into the northern NZSSO, possibly associated with reduced ice volume on East Antarctica but particularly with restriction of the Indonesian gateway and redirection of intensified warm surface flows southwards into the Tasman Sea, as well as complete opening of the Drake gateway by 23 Ma allowing more complete decoupling of cool circum-Antarctic flow from the subtropical waters. During the late Middle-Late Miocene (15-5 Ma), both the STF and SAF proper were established in their present relative positions across and about the Campbell Plateau, respectively, accompanying renewed ice buildup on East Antarctica and formation of a permanent ice sheet on West Antarctica, as well as generally more expansive and intensified circum-Antarctic flow.
The ultimate control on the history of oceanic front development in the NZSSO has been plate tectonics through its influence on the paleogeographic changes of the Australian-New Zealand-Antarctic continents and their intervening oceanic basins, the timing of opening and closing of critical seaways, the potential for submarine ridges and plateaus to exert some bathymetric control on the location of fronts, and the evolving ice budget on the Antarctic continent. The broad trends of the Cenozoic climate curve for New Zealand deduced from fossil evidence in the uplifted marine sedimentary record correspond well to the principal paleoceanographic events controlling the evolution and migration of the oceanic fronts in the NZSSO
Which came first: The disease or the pest? Is there a host mediated spread of Beauveria bassiana (Ascomycota: Hypocreales) by invasive palm pests?
The red palm weevil (RPW) Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae) is threatening the palm family worldwide, causing important economic losses. Current tactics to manage the weevil are largely based on chemical control, although the use of pesticides is hampered by several environmental constraints. Since the first introduction of RPW in Spain in 1996 and during its progressive spread around the Mediterranean basin, the number of reports of natural infection of RPW populations by entomopathogenic fungi (EPF) has been rising for 15 years, and this rise could support a pest-mediated EPF spread. To challenge this hypothesis, we assessed the usefulness of the region of elongation factor 1-alpha (EF1-alpha), Bloc nuclear intergenic region (Bloc) and inter simple sequence repeat (ISSR) markers, alone or in combination, to infer the relationships among Mediterranean Beauveria and Metarhizium strains isolated from the RPW. Second, the effect of abiotic factors, such as temperature, humidity and UV-B radiation, on the germination and growth of these EPFs strains as a function of their genealogy and geographic origin were determined. Finally, the pathogenicity of strains from different genetic clades was evaluated against larvae and adults of R. ferrugineus. The phylogenetic analysis based on the EF-1 alpha gene identified eight different sequences among 24 fungal isolates of four fungal species. Similar clades were clustered when Bloc and ISSR analyses were performed. The results showed that strains of different origins were clustered in the same Glade, and this outcome could be explained by an RPW-mediated EPF spread that was also influenced by time, geographical and other RPW related factors. Neither the response to abiotic factors nor virulence to RPW larvae and adults were related to the sequence type, with all B. bassiana strains well adapted to Mediterraneam climatic conditions. Taken together, these findings may help to select the best strain for RPW management
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