How much potential biodiversity and conservation value can a regenerating rainforest provide? A ‘best-case scenario’ approach from the Peruvian Amazon

The structure and underlying functions of the majority of the world’s tropical forests have been disrupted by human impacts, but the potential biodiversity and conservation value of regenerating forests is still debated. One review suggests that on average, regenerating tropical forests hold 57% (±2.6%) of primary forest species richness, raising doubt about a viable second chance to conserve biodiversity through rainforest regeneration. Average values, however, likely underestimate the potential benefit to biodiversity and conservation because they are drawn from many studies of short-term regeneration and studies confounded by on-going human disturbance. We suggest that the true potential biodiversity and conservation value of regenerating rainforest could be better assessed in the absence of such factors and present a multi-taxa case study of faunal biodiversity in regenerating tropical forest in lowland Amazonia. We found that biodiversity of this regenerating site was higher than might have been expected, reaching 87% (±3.5%) of primary forest alpha diversity and an average of 83% (±6.7) of species estimated to have occurred in the region before disturbance. Further, the regenerating forest held 37 species of special conservation concern, representing 88% of species of highest conservation importance predicted to exist in primary forest from the region. We conclude that this specific regenerating rainforest has high biodiversity and conservation value, and that whilst preserving primary forest is essential, our results suggest that under a best-case scenario of effective conservation management, high levels of biodiversity can return to heavily disturbed tropical forest ecosystems. © Andrew Whitworth, Roger Downie, Rudolf von May, Jaime Villacampa and Ross MacLeod

Canopy bird assemblages are less influenced by habitat age and isolation than understory bird assemblages in Neotropical secondary forest

Secondary forest habitats are increasingly recognized for their potential to conserve biodiversity in the tropics. However, the development of faunal assemblages in secondary forest systems varies according to habitat quality and species‐specific traits. In this study, we predicted that the recovery of bird assemblages is dependent on secondary forest age and level of isolation, the forest stratum examined, and the species’ traits of feeding guild and body mass. This study was undertaken in secondary forests in central Panama; spanning a chronosequence of 60‐, 90‐, and 120‐year‐old forests, and in neighboring old‐growth forest. To give equal attention to all forest strata, we employed a novel method that paired simultaneous surveys in canopy and understory. This survey method provides a more nuanced picture than ground‐based studies, which are biased toward understory assemblages. Bird reassembly varied according to both habitat age and isolation, although it was challenging to separate these effects, as the older sites were also more isolated than the younger sites. In combination, habitat age and isolation impacted understory birds more than canopy‐dwelling birds. Proportions of dietary guilds did not vary with habitat age, but were significantly different between strata. Body mass distributions were similar across forest ages for small‐bodied birds, but older forest supported more large‐bodied birds, probably due to control of poaching at these sites. Canopy assemblages were characterized by higher species richness, and greater variation in both dietary breadth and body mass, relative to understory assemblages. The results highlight that secondary forests may offer critical refugia for many bird species, particularly specialist canopy‐dwellers. However, understory bird species may be less able to adapt to novel and isolated habitats and should be the focus of conservation efforts encouraging bird colonization of secondary forests

Avalanche amplification of a single exciton in a semiconductor nanowire

Interfacing single photons and electrons is a crucial ingredient for sharing quantum information between remote solid-state qubits. Semiconductor nanowires offer the unique possibility to combine optical quantum dots with avalanche photodiodes, thus enabling the conversion of an incoming single photon into a macroscopic current for efficient electrical detection. Currently, millions of excitation events are required to perform electrical read-out of an exciton qubit state. Here we demonstrate multiplication of carriers from only a single exciton generated in a quantum dot after tunneling into a nanowire avalanche photodiode. Due to the large amplification of both electrons and holes (> 10^4), we reduce by four orders of magnitude the number of excitation events required to electrically detect a single exciton generated in a quantum dot. This work represents a significant step towards single-shot electrical read-out and offers a new functionality for on-chip quantum information circuits

Decrease in treatment intensity predicts worse outcome in patients with locally advanced head and neck squamous cell carcinoma undergoing radiochemotherapy

PURPOSE: Radiochemotherapy (RCT) is an effective standard therapy for locally advanced head and neck squamous cell carcinoma (LA-HNSCC). Nonetheless, toxicity is common, with patients often requiring dose modifications. METHODS: To investigate associations of RCT toxicities according to CTCAE version 5.0 and subsequent therapy modifications with short- and long-term treatment outcomes, we studied all 193 patients with HNSCC who received RCT (70 Gy + platinum agent) at an academic center between 03/2010 and 04/2018. RESULTS: During RCT, 77 (41%, 95% CI 34-49) patients developed at least one ≥ grade 3 toxicity, including seven grade 4 and 3 fatal grade 5 toxicities. The most frequent any-grade toxicities were xerostomia (n = 187), stomatitis (n = 181), dermatitis (n = 174), and leucopenia (n = 98). Eleven patients (6%) had their radiotherapy schedule modified (mean radiotherapy dose reduction = 12 Gy), and 120 patients (64%) had chemotherapy modifications (permanent discontinuation: n = 67, pause: n = 34, dose reduction: n = 7, change to other chemotherapy: n = 10). Objective response rates to RCT were 55% and 88% in patients with and without radiotherapy modifications (p = 0.003), and 84% and 88% in patients with and without chemotherapy modifications (p = 0.468), respectively. Five-year progression-free survival estimates were 20% and 50% in patients with and without radiotherapy modifications (p = < 0.001), and 53% and 40% in patients with and without chemotherapy modifications (p = 0.88), respectively. CONCLUSIONS: Reductions of radiotherapy dose were associated with impaired long-term outcomes, whereas reductions in chemotherapy intensity were not. This suggests that toxicities during RCT should be primarily managed by modifying chemotherapy rather than radiotherapy

Untangling the imprints of climate, geography and land use/cover on bird diversity in the South American Gran Chaco

To evaluate the structure of bird communities throughout the South American Gran Chaco determining the effects of climate, geography and land use/land cover in bird beta diversity, as well as to understand the beta diversity processes underlying land use changes across broad spatial ranges. Location: South American Gran Chaco. Taxon: Birds. Methods: We constructed a site-by-species matrix with occurrence probabilities of 293 bird species across 2,669 spatial units tiling completely the study area. Based on this matrix, we calculated pairwise dissimilarities scores and performed a hierarchical cluster analysis for describing the spatial configuration of dissimilarities. The clustering result was spatially represented through an original venation map with boundaries between sites widened in the function of their distance in the dendrogram. We used the Generalized Dissimilarity Modelling approach to model beta diversity, using geographic distance, climatic and land use/land cover information as predictors. We mapped beta diversity patterns using colour theory and the HSV colour model. We identified two main clusters of sites across the Gran Chaco, which represent environmentally different sites and harbour very distinct assemblages of species. These main groups are separated by two natural delimiters: The Bermejo-Pilcomayo interfluvium and the Lower Paraná floodplain. Overall, we observed that the percentage of cropland and climatic variables were important shapers of bird beta diversity. Main conclusions: We provide the first area-wide assessment of land use/land cover effects on bird beta diversity for the Gran Chaco. The distribution of croplands has a marked influence on bird beta diversity at regional scale highlighting the role of anthropic changes in reshaping bird beta diversity within the ecoregion. Taking into account the global increasing conversion of forests into croplands, a growing footprint of land use changes over geographical patterns of bird diversity in forest biomes can be anticipated.Fil: Nazaro, María Gabriela. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Dos Santos, Daniel Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; ArgentinaFil: Torres, Ricardo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Baumann, Matthias. Humboldt-universitat Zu Berlin. Geography Department.; AlemaniaFil: Blendinger, Pedro Gerardo. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; Argentin

Parque Estadual da Ilha Grande ameaças ambientais e diretrizes para conservação

O Parque Estadual da Ilha Grande é somente uma parte (5.594 hectares) de toda a ilha (19.300 hectares) localizada na costa sul do Estado do Rio de Janeiro, entre as cidades de Mangaratiba e Angra dos Reis. Aproximadamente a metade da área do Parque (47%) é coberta por floresta densa, ombrófila, de Mata Atlântica. A mata secundária, em processo de regeneração por sucessão ecológica, está perto da maturidade (43%) e o restante (10%) é composto por áreas antropizadas (1%), afloramentos rochosos com vegetação herbácea (7%), restingas, manguezais e praias (2%). A fauna está bem representada, mas já mostra sinais de degradação com a presença de espécies introduzidas. A análise conduzida sobre o grau de ameaças mostrou que a floresta ombrófila densa está relativamente bem conservada, enquanto a mata secundária, as restingas e mangues e a vegetação herbácea dos terrenos rochosos (e suas respectivas faunas) estão categorizadas como vulneráveis. A área onde há ocupação humana é categorizada como ameaçada. Contraditoriamente, a maior ameaça à biodiversidade local em suas unidades de paisagens é o turismo. Uma vez que a costa onde se localiza a Ilha Grande tem alto valor cênico (conhecida como costa verde pelo constraste entre o mar e o verde da Mata Atlântica que cobre a Serra do Mar), o turismo tem alto potencial para se tornar o meio de atingir a sustentabilidade econômica para conservação. No entanto, por causa do turismo desorganizado e sem controle hoje em prática, com visitantes em número superior à capacidade de suporte na alta estação, a proliferação de hotéis, pousadas e acampamentos e o conseqüente esgoto a céu aberto, depósito de lixo e outras atividades prejudiciais à biodiversidade são as principais ameaças. _______________________________________________________________________________ ABSTRACTThe State Park of Ilha Grande is only a part (5,594 hectares) of the entire island (19,300 hectares) which is located off the south coast of Rio de Janeiro state, between the cities of Mangaratiba and Angra dos Reis. Approximately half of the Park area (47%) is covered by dense Atlantic forest. The secondary forest growth is in a process of ecological succession close to attaining maturity (43%) and the remaining part (10%) is composed of human-altered areas (1%), rocky outcrops with herbaceous vegetation (7%), mangroves and beaches (2%). The fauna is well represented but already shows signs of degradation with introduced species. The analysis of the degree of threat has shown that the dense forest habitat has a relatively stable status of conservation while the secondary forest, the mangrove and the herbaceous vegetation on rocky outcrops (and their fauna) are categorized as vulnerable. The area altered by human occupation is considered threatened. Since the coastal area where Ilha Grande is located is well known for its beautiful scenery (known as the green coast, because of the contrast between the ocean and the Atlantic forest covering the Serra do Mar mountain chain). There is a strong possibility for tourism to become the means in which to achieve economic sustainability for conservation. Contradictorily, tourism is also the major threat to local biodiversity and its landscape units. Because tourism is not organized and controlled, during high season the numbers grow above local capacity, giving rise to a proliferation of hotels, guesthouses and camping grounds. The resulting untreated open sewage, random garbage disposal and other harmful activities form the major threats to biodiversity

Determinants of the voltage dependence of G protein modulation within calcium channel β subunits

CaVβ subunits of voltage-gated calcium channels contain two conserved domains, a src-homology-3 (SH3) domain and a guanylate kinase-like (GK) domain with an intervening HOOK domain. We have shown in a previous study that, although Gβγ-mediated inhibitory modulation of CaV2.2 channels did not require the interaction of a CaVβ subunit with the CaVα1 subunit, when such interaction was prevented by a mutation in the α1 subunit, G protein modulation could not be removed by a large depolarization and showed voltage-independent properties (Leroy et al., J Neurosci 25:6984–6996, 2005). In this study, we have investigated the ability of mutant and truncated CaVβ subunits to support voltage-dependent G protein modulation in order to determine the minimal domain of the CaVβ subunit that is required for this process. We have coexpressed the CaVβ subunit constructs with CaV2.2 and α2δ-2, studied modulation by the activation of the dopamine D2 receptor, and also examined basal tonic modulation. Our main finding is that the CaVβ subunit GK domains, from either β1b or β2, are sufficient to restore voltage dependence to G protein modulation. We also found that the removal of the variable HOOK region from β2a promotes tonic voltage-dependent G protein modulation. We propose that the absence of the HOOK region enhances Gβγ binding affinity, leading to greater tonic modulation by basal levels of Gβγ. This tonic modulation requires the presence of an SH3 domain, as tonic modulation is not supported by any of the CaVβ subunit GK domains alone

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