Island biodiversity in peril: Anticipating a loss of mammals' functional diversity with future species extinctions.

Islands are biodiversity hotspots that host unique assemblages. However, a substantial proportion of island species are threatened and their long-term survival is uncertain. Identifying and preserving vulnerable species has become a priority, but it is also essential to combine this information with other facets of biodiversity like functional diversity, to understand how future extinctions might affect ecosystem stability and functioning. Focusing on mammals, we (i) assessed how much functional space would be lost if threatened species go extinct, (ii) determined the minimum number of extinctions that would cause a significant functional loss, (iii) identified the characteristics (e.g., biotic, climatic, geographic, or orographic) of the islands most vulnerable to future changes in the functional space, and (iv) quantified how much of that potential functional loss would be offset by introduced species. Using trait information for 1474 mammal species occurring in 318 islands worldwide, we built trait probability density functions to quantify changes in functional richness and functional redundancy in each island if the mammals categorized by IUCN as threatened disappeared. We found that the extinction of threatened mammals would reduce the functional space in 63% of the assessed islands, although these extinctions in general would cause a reduction of less than 15% of their overall functional space. Also, on most islands, the extinction of just a few species would be sufficient to cause a significant loss of functional diversity. The potential functional loss would be higher on small, isolated, and/or species-rich islands, and, in general, the functional space lost would not be offset by introduced species. Our results show that the preservation of native species and their ecological roles remains crucial for maintaining the current functioning of island ecosystems. Therefore, conservation measures considering functional diversity are imperative to safeguard the unique functional roles of threatened mammal species on islands.

Magnetochiroptical nanocavities in hyperbolic metamaterials enable sensing down to the few-molecule level.

In this work, we combine the concepts of magnetic circular dichroism, nanocavities, and magneto-optical hyperbolic metamaterials (MO-HMMs) to demonstrate an approach for sensing down to a few molecules. Our proposal comprises a multilayer MO-HMM with a square, two-dimensional arrangement of nanocavities. The magnetization of the system is considered in polar configuration, i.e., in the plane of polarization and perpendicular to the plane of the multilayer structure. This allows for magneto-optical chirality to be induced through the polar magneto-optical Kerr effect, which is exhibited by reflected light from the nanostructure. Numerical analyses under the magnetization saturation condition indicate that magnetic circular dichroism peaks can be used instead of reflectance dips to monitor refractive index changes in the analyte region. Significantly, we obtained a relatively high sensitivity value of S = 40 nm/RIU for the case where refractive index changes are limited to the volume inside nanocavities, i.e., in the limit of a few molecules (or ultralow concentrations), while a very large sensitivity of S = 532 nm/RIU is calculated for the analyte region distributed along the entire superstrate layer.

Active manipulation of radiated fields by a magnetoplasmonic half-wave dipole nanoantenna.

We demonstrate a concept for the active manipulation of radiated fields by a magnetoplasmonic half-wave dipole nanoantenna. Our idea comprises a two arms nanoantenna, made of metallic ferromagnetic cobalt-silver alloy (Co6Ag94), inspired by the analogous radio frequency half-wave dipole antenna design. Numerical results, obtained under the magnetization saturation condition, indicate a tilting of the radiated beam depending on the magnitude and sense of the magnetization of the ferromagnetic material. Significantly, we obtained tilting angles as large as ±9.7∘ around the y axis for the magnetization placed along the x or z axes, respectively. Results in this work not only open up a new, to the best of our knowledge, way to dynamically manipulate the beam steering at the chip-scale, but also contribute to unveil novel magneto-optical effects at the nanoscale.

Clinical and echocardiographic characteristics after six months of sacubitril/valsartan in Chagas heart disease - A case series.

Chagas cardiomyopathy is the most prevalent non-ischaemic cardiomyopathy in Latin America, with high morbidity and mortality even today. Treatment of these patients is based on the use of medications for heart failure. This study evaluated a case series of patients with Chagas heart disease who used sacubitril/valsartan at a referral hospital for this disease in Brazil. After 6 months, there was a symptomatic improvement in these individuals assessed by the New York Heart Association (NYHA) functional class, with a 44.3% reduction in the absolute number of patients classified as III-IV in the period (P = 0.035), but without changes in the parameters on the echocardiogram for reverse ventricular remodelling. There was a high mortality rate and number of hospitalizations. These results emphasize the importance of studying the use of sacubitril/valsartan in Chagas heart disease to better describe its effectiveness considering the particularities of these individuals.

All-dielectric magnetophotonic gratings for maximum TMOKE enhancement.

All-dielectric nanophotonic devices are promising candidates for future lossless (bio)sensing and telecommunication applications. Active all-dielectric magnetophotonic devices, where the optical properties can be controlled by an externally applied magnetic field, have triggered great research interest. However, magneto-optical (MO) effects are still low for applications. Here, we demonstrate a concept for the enhancement of the transverse MO Kerr effect (TMOKE), with amplitudes of up to 1.85, i.e., close to the maximum theoretical values of ±2 (in transmission). Our concept exploits the lateral leaky Bloch-modes to enhance the TMOKE, under near-zero transmittance conditions. Potential applications in (bio)sensing structures are numerically demonstrated. The effects of optical losses were studied using different combinations of materials. Significantly, we demonstrate TMOKE enhancements of two orders of magnitude in relation to recent experimental studies, using the same building materials.

Design of Plasmonic Yagi-Uda Nanoantennas for Chip-Scale Optical Wireless Communications.

Optical wireless transmission has recently become a major cutting-edge alternative for on-chip/inter-chip communications with higher transmission speeds and improved power efficiency. Plasmonic nanoantennas, the building blocks of this new nanoscale communication paradigm, require precise design to have directional radiation and improved communication ranges. Particular interest has been paid to plasmonic Yagi-Uda, i.e., the optical analog of the conventional Radio Frequency (RF) Yagi-Uda design, which may allow directional radiation of plasmonic fields. However, in contrast to the RF model, an overall design strategy for the directional and optimized front-to-back ratio of the radiated far-field patterns is lacking. In this work, a guide for the optimized design of Yagi-Uda plasmonic nanoantennas is shown. In particular, five different design conditions are used to study the effects of sizes and spacing between the constituent parts (made of Au). Importantly, it is numerically demonstrated (using the scattered fields) that closely spaced nanoantenna elements are not appropriated for directional light-to-plasmon conversion/radiation. In contrast, if the elements of the nanoantenna are widely spaced, the structure behaves like a one-dimensional array of nanodipoles, producing a funnel-like radiation pattern (not suitable for on-chip wireless optical transmission). Therefore, based on the results here, it can be concluded that the constituent metallic rib lengths must be optimized to exhibit the resonance at the working wavelength, whilst their separations should follow the relation λeff/π, where λeff indicates the effective wavelength scaling for plasmonic nanostructures.

Magnetically Tunable Micro-Ring Resonators for Massive Magneto-Optical Modulation in Dense Wavelength Division Multiplexing Systems.

We demonstrate, numerically, a new concept for on-chip magneto-optical (MO) modulation in dense wavelength division multiplexing (DWDM) applications. Our idea uses materials and mechanisms that are compatible with current silicon-on-insulator fabrication and CMOS technologies for monolithic integration. The physics behind our idea stems in the exploitation of the enhanced MO activity of a micro-ring, made of cerium substituted yttrium iron garnet (Ce:YIG) material, to actively manipulate the resonance wavelengths of an adjacent micro-ring resonator (MRR) of silicon (Si). This active manipulation of the latter MO-MRR structure is used to modulate the optical signal traveling through a side-coupled Si bus waveguide. Moreover, by proper tailoring multiple MO-MRRs (side-coupled to the single Si bus waveguide) to match wavelength channels in DWDM across the entire C-band optical communications spectrum, we extend our proposal to massive and dynamic MO modulation in DWDM applications. Significantly, we noticed that the active MO shifting of the resonant wavelength (used for MO modulation here) can be used for improvements in the spectrum utilization efficiency in future elastic optical networks (EONs).

Magneto-optical micro-ring resonators for dynamic tuning of add/drop channels in dense wavelength division multiplexing applications.

We numerically demonstrate an all-dielectric approach for magnetically tunable add/drop of optical channels in dense wavelength division multiplexing applications. Our concept comprises a micro-ring resonator, with an inner magneto-optical disk, side-coupled to two waveguides. The simulation results, obtained within the ITU-T G.694.1 recommendation, indicate high performance add/drop of odd and even optical channels (along the entire C-band) by flipping the intrinsic magnetization of the disk. Since the simulations were performed with CMOS-compatible materials, it is hoped that the structure proposed here can be integrated into future ultrafast optical communication networks.

Taxonomic, functional and phylogenetic bat diversity decrease from more to less complex natural habitats in the Amazon.

The high levels of biodiversity in the Amazon are maintained mostly due to its composition as a natural mosaic of different habitats, including both unflooded and flooded forests, campinaranas, and savannahs. Here, we compared multiple dimensions of α- and ß- bat biodiversity between four natural Amazonian habitats (savannah, campinarana, forest patches, and continuous forest). In addition, we explored the extent to which bat communities in the different habitats are nested within one another, and compared the community-level functional uniqueness and community-weighted mean traits between habitats. Our results show that taxonomic, functional and phylogenetic α-diversity of bats is higher in continuous forest than in any of the other habitat types. The continuous forest also harbours more unique species, and indeed, the bat community assemblages in the less-complex habitats, including forest patches, campinarana and savannahs, are taxonomic, functional and phylogenetic sub-sets of the assemblage found in the continuous forest. By examining ß-diversity partitions and species composition, we are able to shed light on the mechanisms behind the variation in diversity between the four habitat types, which reflect a process of environmental sorting along a habitat gradient going from a more complex to a less complex habitat. We conclude that nesting patterns along the mosaic of habitats are determined by differences in complexity between habitats and that taxonomic and functional uniqueness contribute to overall regional bat diversity and functionality. Ongoing human-induced disturbances of these habitats could provoke an unprecedented loss of bat diversity and functionality with negative consequences for biodiversity and ecosystem services.

Refractive index of ZnO ultrathin films alternated with Al2O3 in multilayer heterostructures.

The design of optoelectronic devices made with ZnO superlattices requires the knowledge of the refractive index, which currently can be done only for films thicker than 30 nm. In this work, we present an effective medium approach to determine the refractive index of ZnO layers as thin as 2 nm. The approach was implemented by determining the refractive index of ZnO layers ranging from 2 nm to 20 nm using spectroscopic ellipsometry measurements in multilayers. For a precise control of morphology and thickness, the superlattices were fabricated with atomic layer deposition (ALD) with alternating layers of 2 nm thick Al2O3 and ZnO, labeled as N ZnO-Al2O3, where N = 10, 20, 30, 50, 75 and 100. The total thickness of all superlattices was kept at 100 nm. The approach was validated by applying it to similar superlattices reported in the literature and fitting the transmittance spectra of the superlattices.

Plasmonics for Telecommunications Applications.

Plasmonic materials, when properly illuminated with visible or near-infrared wavelengths, exhibit unique and interesting features that can be exploited for tailoring and tuning the light radiation and propagation properties at nanoscale dimensions. A variety of plasmonic heterostructures have been demonstrated for optical-signal filtering, transmission, detection, transportation, and modulation. In this review, state-of-the-art plasmonic structures used for telecommunications applications are summarized. In doing so, we discuss their distinctive roles on multiple approaches including beam steering, guiding, filtering, modulation, switching, and detection, which are all of prime importance for the development of the sixth generation (6G) cellular networks.

Surface Plasmon Resonances in Sierpinski-Like Photonic Crystal Fibers: Polarization Filters and Sensing Applications.

We investigate the plasmonic behavior of a fractal photonic crystal fiber, with Sierpinski-like circular cross-section, and its potential applications for refractive index sensing and multiband polarization filters. Numerical results were obtained using the finite element method through the commercial software COMSOL Multiphysics®. A set of 34 surface plasmon resonances was identified in the wavelength range from λ=630 nm to λ=1700 nm. Subsets of close resonances were noted as a consequence of similar symmetries of the surface plasmon resonance (SPR) modes. Polarization filtering capabilities are numerically shown in the telecommunication windows from the O-band to the L-band. In the case of refractive index sensing, we used the wavelength interrogation method in the wavelength range from λ=670 nm to λ=790 nm, where the system exhibited a sensitivity of S(λ)=1951.43 nm/RIU (refractive index unit). Due to the broadband capabilities of our concept, we expect that it will be useful to develop future ultra-wide band optical communication infrastructures, which are urgent to meet the ever-increasing demand for bandwidth-hungry devices.

Detection of "Candidatus Rickettsia wissemanii" in ticks parasitizing bats (Mammalia: Chiroptera) in the northern Brazilian Amazon.

A total of 482 bats representing 32 species and two families were captured in the Amazon forests of the Amapá state in northern Brazil. Nineteen Artibeus planirostris bats (3.9 %) were infested with 160 ticks, all identified as Ornithodoros hasei. Three pools of larvae were screened for rickettsial DNA via polymerase chain reaction (PCR) targeting three rickettsial genes: gltA, ompA and htrA. Only one of them yielded an amplicons of the expected size for all three molecular assays. Comparisons of the obtained sequences including a phylogenetic analysis confirmed the occurrence of "Candidatus Rickettsia wissemanii" in Brazil.

Ultralow chirp photonic crystal fiber Mach-Zehnder interferometer.

A photonic crystal fiber Mach-Zehnder interferometer design was optimized to obtain high performance and ultralow chirp. Two long-period gratings were used to excite the cladding modes, and the rich structure of the cladding was tailored to obtain a slightly chirped free spectral range, as required by the Telecommunication Standardization Sector of the International Telecommunication Union (ITU-T) Norm G.694.1. Finally, a fabrication tolerance analysis was performed. The advantages of the proposed device are an ultralow chirp, high bandwidth, and fabrication robustness tolerance.

Magnetoplasmonic Nanoantennas for On-Chip Reconfigurable Optical Wireless Communications.

On-chip wireless communications require optical nanoantennas with dynamically tunable radiation patterns, which may allow for higher integration with multiple nanoantennas instead of two fixed nanoantennas in existing approaches. In this paper, we introduce a concept to enable active manipulation of radiated beam steering using applied magnetic fields. The proposed system consists of a highly directive Yagi-Uda-like arrangement of magnetoplasmonic nanoribs made of Co6Ag94 and immersed in SiO2. Numerical demonstration of the tilting of the radiated beam from the nanoantenna on its plane is provided with full-wave electromagnetic simulations using the finite element method. The tilt direction of the radiated beam can be changed by reversing the magnetization direction, while the conventional plasmonic nanoantenna pattern is recovered by demagnetizing the system. The geometry of the nanoantenna can be tailored to work at optical or infrared wavelengths, but a proof of concept for λ = 700 nm is conducted for taking advantage of the high magneto-optical activity of Co6Ag94. The design was based on experimental data for materials that can be fabricated via nanolithography, thus permitting magnetically on-chip reconfigurable optical wireless communications.

Seasonal variation and host sex affect bat-bat fly interaction networks in the Amazonian savannahs.

Bats are the second-most diverse group of mammals in the world, and bat flies are their main parasites. However, significant knowledge gaps remain regarding these antagonistic interactions, especially since diverse factors such as seasonality and host sex can affect their network structures. Here, we explore the influence of such factors by comparing species richness and composition of bat flies on host bats, as well as specialization and modularity of bat-bat fly interaction networks between seasons and adult host sexes. We captured bats and collected their ectoparasitic flies at 10 sampling sites in the savannahs of Amapá State, northeastern region of the Brazilian Amazon. Despite female bats being more parasitized and recording greater bat fly species richness in the wet season, neither relationship was statistically significant. The pooled network could be divided into 15 compartments with 54 links, and all subnetworks comprised >12 compartments. The total number of links ranged from 27 to 48 (for the dry and wet seasons, respectively), and female and male subnetworks had 44 and 41 links, respectively. Connectance values were very low for the pooled network and for all subnetworks. Our results revealed higher bat fly species richness and abundance in the wet season, whereas specialization and modularity were higher in the dry season. Moreover, the subnetwork for female bats displayed higher specialization and modularity than the male subnetwork. Therefore, both seasonality and host sex contribute in different ways to bat-bat fly network structure. Future studies should consider these factors when evaluating bat-bat fly interaction networks.

Global review and guidelines to avoid opportunistic predation of birds and bats in mist nets.

Mist nets are one of the most widely used techniques in the study of birds and bats worldwide. However, a number of risks are involved, including opportunistic predation. Given this potential cost, here we: (1) review the global literature to understand the factors that might contribute to predation risk for birds and bats captured in mist nets; (2) review existing guidelines for best practice use of mist nets; and (3) based on our reviews, recommend new guidelines for the use of mist nets to minimize the risk of opportunistic predation. Based on keyword in English, Spanish, Portuguese, and French, and using Google Scholar, Scopus, SciElo, and Web of Science, we found 48 articles reporting opportunistic predation. In the included articles, 178 predation events, involving 52 predator and 84 prey species, were reported. In most of the reports, the mist nets were placed at ground level, the bats and birds were preyed on from the shelf closest to the ground, the mist-net checks occurred at intervals of 1 h or 30 min and the most common predators were arboreal and scansorial species (primates and marsupials). Despite the occurrences of predation in 13 countries, guidelines for best practice mist-net use were found in only three, despite extensive searches and contact with key people in each country. Based on the existing guidelines and our results, we recommend that mist nets be fixed with the lowest shelf at least 50 cm above ground level and be checked at 15-min intervals; when predators are observed near mist nets, the nets either be constantly observed, closed, or relocated; suppressed the vegetation around the mist nets; captured animals be removed from the mist nets as soon as possible, and more than one researcher/technician should be in the field at all times.

Design of Nanoarchitectures for Magnetoplasmonic Biosensing with Near-Zero-Transmittance Conditions.

Nanostructures exhibiting large transverse magneto-optical Kerr effect (TMOKE) are required for magnetoplasmonic biosensing if the aim is the minituarization and integration into microfluidic devices. In this work, we present a general strategy to design nanoarchitectures with enhanced TMOKE, which consist of an arrangement of gold ribs deposited on an magneto-optical (MO) dielectric slab of Bi:YIG (bismuth-substituted yttrium iron garnet) with a SiO2 substrate surrounded by water. Using the finite element method (FEM), we demonstrate numerically that the near-zero-transmittance condition is the most important requirement for high TMOKE values. This can be reached through geometric optimization of the nanoarchitecture by tuning the period, height, and width of the grating, thus leading to resonances at wavelengths where the MO dielectric slab has high MO activity. We also show that the TMOKE amplitude can be further increased if losses in metal ribs are reduced. For a magnetoplasmonic grating with optimized geometry, we demonstrated the potential detection of biologically relevant analytes with sensitivity in the order of 102 nm/RIU (refractive index unit). Since the nanoarchitecture proposed is experimentally feasible with, e.g., nanolithography techniques, one may expect that the design strategy may inspire the development of efficient magnetoplasmonic sensing platforms.

Judgement of the multidisciplinary team is an important predictor of mortality after cardiac resynchronization therapy.

AIMS: Cardiac resynchronization therapy (CRT) in appropriately selected patients with heart failure improves symptoms and survival. It is necessary to correctly identify patients who will benefit most from this therapy. We aimed to assess the predictive power of the multidisciplinary team's clinical judgement in the short-term death after CRT implantation. METHODS AND RESULTS: Patients with heart failure and referred for the first CRT implant were prospectively included. Prior to implantation, all patients underwent a systematic assessment with a team composed of social work, nurse, psychologist, nutritionist, and clinical cardiologist. Based on this assessment, patients could be contraindicated to CRT or referred to the procedure as favourable or unfavourable. All patients should complete 12 months of follow-up; 172 patients were referred for CRT, 21 (12.2%) were contraindicated after the multidisciplinary team evaluation, 71 (47%) referred to CRT as non-favourable implants, and 80 (53%) as favourable implants. All-cause mortality occurred in only 2 (2.5%) patients in the favourable group and in 30 (42.3%) in the non-favourable group, P < 0.001 (log rank). Among the 20 variables used as possible predictors of worse prognosis by the multidisciplinary team, four were independently associated with mortality in the follow-up after the multivariate analysis: 1 year MAGGIC score between 40% and 49%, relative risk (RR) 5.0, 95% confidence interval (CI) 1.3-18.6, P = 0.016; poor pharmacological adherence, RR 4.9, 95% CI 1.6-15.6, P = 0.007; glomerular filtration rate <35 mL/min/1.73 m2 , RR 3.0, 95% CI 1.1-8.5, P = 0.041; and right ventricular dysfunction, RR 2.6, 95% CI 1.2-5.7, P = 0.018. CONCLUSIONS: The clinical judgement before the CRT implantation performed by a multidisciplinary team through the analysis of clinical and psychosocial variables is a strong predictor of short-term mortality.