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Introduction: Four counties within the Atlanta, Georgia 20‐county eligible metropolitan area (EMA) are currently prioritized by the US "Ending the HIV Epidemic" (EHE) initiative which aims for a 90% reduction in HIV incidence by 2030. Disparities driving Atlanta's HIV epidemic warrant an examination of local service availability, unmet needs and organizational capacity to reach EHE targets. We conducted a mixed‐methods evaluation of the Atlanta EMA to examine geographic HIV epidemiology and distribution of services, service needs and organization infrastructure for each pillar of the EHE initiative. Methods: We collected 2021 county‐level data (during June 2022), from multiple sources including: AIDSVu (HIV prevalence and new diagnoses), the Centers for Disease Control and Prevention web‐based tools (HIV testing and pre‐exposure prophylaxis [PrEP] locations) and the Georgia Department of Public Health (HIV testing, PrEP screenings, viral suppression and partner service interviews). We additionally distributed an online survey to key local stakeholders working at major HIV care agencies across the EMA to assess the availability of services, unmet needs and organization infrastructure (June−December 2022). The Organizational Readiness for Implementing Change questionnaire assessed the organization climate for services in need of scale‐up or implementation. Results: We found racial/ethnic and geographic disparities in HIV disease burden and service availability across the EMA—particularly for HIV testing and PrEP in the EMA's southern counties. Five counties not currently prioritized by EHE (Clayton, Douglas, Henry, Newton and Rockdale) accounted for 16% of the EMA's new diagnoses, but <9% of its 177 testing sites and <7% of its 130 PrEP sites. Survey respondents (N = 48; 42% health agency managers/directors) reported high unmet need for HIV self‐testing kits, mobile clinic testing, HIV case management, peer outreach and navigation, integrated care, housing support and transportation services. Respondents highlighted insufficient existing staffing and infrastructure to facilitate the necessary expansion of services, and the need to reduce inequities and address intersectional stigma. Conclusions: Service delivery across all EHE pillars must substantially expand to reach national goals and address HIV disparities in metro Atlanta. High‐resolution geographic data on HIV epidemiology and service delivery with community input can provide targeted guidance to support local EHE efforts. [ABSTRACT FROM AUTHOR]

The article discusses the progress made towards ending the AIDS epidemic by 2030, as pledged by world leaders in 2015. While significant strides have been made in terms of initiating HIV-positive individuals on antiretroviral medication and reducing AIDS-related deaths, perinatal transmissions, and new acquisitions, challenges remain in ending new acquisitions and eliminating stigma and discrimination. The COVID-19 pandemic has further complicated efforts to achieve these goals. The article emphasizes the need for renewed political commitment, innovative approaches, collaboration, and sustained funding beyond 2030. It also highlights the importance of research for a vaccine and a cure, as well as the development of new antiretroviral drugs and prevention methods. The article acknowledges the achievements of universal access to treatment and prevention of vertical transmission but emphasizes the need to reach pregnant women who do not use prenatal health services. Community involvement, reducing stigma and discrimination, and addressing social determinants of health are also crucial. The article concludes by expressing hope that with unwavering effort, political commitment, and global solidarity, the goals of zero new acquisitions, zero AIDS-related deaths, and zero stigma and discrimination can still be achieved within this decade. [Extracted from the article]

Understanding the ecological consequences of supplemental feeding to both hummingbirds and the plants they pollinate is complicated by logistical challenges associated with assessing relative dietary resource use with commonly applied observational methods. Here, we describe the results of research conducted to assess the relative use of feeder and flower nectar by Broad‐tailed (Selasphorus platycercus) and Rufous hummingbirds (Selasphorus rufus) using two distinct methodological variations to measure the δ13C values of exhaled CO2. Because of the relatively quick time in which both species switch from exogenous to endogenous resources to fuel metabolism, our experiment allowed us to assess resource use at two timescales. Our results suggest variability in the relative contributions of the two dietary sources within and among species and timescales, with most birds employing a mixture of feeder and flower sugars as fuel sources. This diversity in relative resource use may mitigate potential negative effects of supplemental feeding on hummingbirds and their plant symbionts. [ABSTRACT FROM AUTHOR]

Ruxolitinib is a US Food and Drug Administration–approved orally administered Janus kinase (1/2) inhibitor that reduces cytokine‐induced inflammation. As part of a randomized, phase 2, open‐label trial, ruxolitinib (10 mg twice daily) was administered to HIV‐positive, virologically suppressed individuals (33 men, 7 women) on antiretroviral therapy (ART) for 5 weeks. Herein, we report the population PK subsequently determined from this study. Plasma concentrations of ruxolitinib (294 samples) and antiretroviral agents were measured at week 1 (N = 39 participants) and week 4 or 5 (N = 37). Ruxolitinib PK was adequately described with a 2‐compartment model with first‐order absorption and elimination with distribution volumes normalized to mean body weight (91.5 kg) and a separate typical clearance for participants administered efavirenz (a known cytochrome P450 3A4 inducer). Participants administered an ART regimen with efavirenz had an elevated typical apparent oral clearance versus the integrase inhibitor regimen group (22.5 vs 12.9 L/hr; N = 14 vs 25). Post hoc predicted apparent oral clearance was likewise more variable and higher (P <.0001) in those administered efavirenz. There was an ≈25% variation in ruxolitinib plasma exposures between week 1 and week 4/5. ART plasma concentrations resembled those from PK studies without ruxolitinib. Therefore, integrase inhibitor–based ART regimens may be preferred over efavirenz‐based regimens when ruxolitinib is administered to HIV‐positive individuals. [ABSTRACT FROM AUTHOR]

Introduction: COVID‐19 parallels HIV in many ways. Socio‐behavioural science has been critical in elucidating the context and factors surrounding individual levels of engagement with known effective prevention and treatment tools for HIV, thus offering important lessons for ongoing efforts to combat the COVID‐19 pandemic. Discussion: Non‐adherence to effective disease mitigation strategies (e.g. condoms for HIV and masks for COVID‐19) can be attributed in part to prioritizing comfort, convenience and individual autonomy over public health. Importantly, misinformation can fuel denialism and conspiracies that discredit scientific knowledge and motivate nonadherence. These preferences and the extent to which individuals can act on their preferences may be constrained by the structures and culture in which they live. Both HIV and COVID‐19 have been politicized and influenced by evolving recommendations from scientists, clinicians, policymakers and politically motivated organizations. While vaccines are vital for ending both pandemics, their impact will depend on availability and uptake. Four decades of experience with the HIV epidemic have shown that information alone is insufficient to overcome these challenges; interventions must address the underlying, often complex factors that influence human behaviour. This article builds from socio‐behavioural science theory and describes practical and successful approaches to enable and support adherence to prevention and treatment strategies, including vaccine adoption. Key methods include reframing tools to enhance motivation, promoting centralized sources of trusted information, strategic development and messaging with and within key populations (e.g. through social media) and appealing to self‐empowerment, altruism and informed decision making. Orchestrated evidence‐based activism is needed to overcome manipulative politicization, while consistent transparent messaging around scientific discoveries and clinical recommendations are critical for public acceptance and support. Ultimately, the effectiveness of COVID‐19 vaccines will depend on our ability to engender trust in the communities most affected. Conclusions: Many lessons learned from socio‐behavioural science in the HIV pandemic are applicable to the COVID‐19 pandemic. Individual behaviour must be understood within its interpersonal and societal context to address the current barriers to adherence to disease‐mitigating strategies and promote an effective response to the COVID‐19 pandemic, which is likely to be endured for the foreseeable future. [ABSTRACT FROM AUTHOR]

Public narratives often attribute the opioid overdose epidemic in the United States to liberal prescribing practices by health care providers. Consequently, new monitoring guidelines for the management of opioid prescriptions in patients with chronic pain have become recognized as key strategies for slowing this tide of overdose deaths. This article examines the social and ontological terrain of opioid‐based pain management in an HIV clinic in the context of today's opioid overdose epidemic. We engage with anthropological analyses of contemporary drug policy and the nonverbal/performative ways patients and clinicians communicate to theorize the social context of the opioid overdose epidemic as a "situation," arguing that the establishment of new monitoring strategies (essentially biomedical audit strategies) trouble patient subjectivity in the HIV clinic—a place where that subjectivity has historically been protected and prioritized in the establishment of care. [ABSTRACT FROM AUTHOR]

Introduction: Due to factors associated with structural racism, Black men who have sex with men (MSM) living with HIV are less likely to be virally suppressed compared to white MSM. Most of these data come from clinical cohorts and modifiable reasons for these racial disparities need to be defined in order to intervene on these inequities. Therefore, we examined factors associated with racial disparities in baseline viral suppression in a community‐based cohort of Black and white MSM living with HIV in Atlanta, GA. Methods: We conducted an observational cohort of Black and white MSM living with HIV infection in Atlanta. Enrolment occurred from June 2016 to June 2017 and men were followed for 24 months; laboratory and behavioural survey data were collected at 12 and 24 months after enrolment. Explanatory factors for racial disparities in viral suppression included sociodemographics and psychosocial variables. Poisson regression models with robust error variance were used to estimate prevalence ratios (PR) for Black/white differences in viral suppression. Factors that diminished the PR for race by ≥5% were considered to meaningfully attenuate the racial disparity and were included in a multivariable model. Results: Overall, 26% (104/398) of participants were not virally suppressed at baseline. Lack of viral suppression was significantly more prevalent among Black MSM (33%; 69/206) than white MSM (19%; 36/192) (crude Prevalence Ratio (PR) = 1.6; 95% CI: 1.1 to 2.5). The age‐adjusted Black/white PR was diminished by controlling for: ART coverage (12% decrease), housing stability (7%), higher income (6%) and marijuana use (6%). In a multivariable model, these factors cumulatively mitigated the PR for race by 21% (adjusted PR = 1.1 [95% CI: 0.8 to 1.6]). Conclusions: Relative to white MSM, Black MSM living with HIV in Atlanta were less likely to be virally suppressed. This disparity was explained by several factors, many of which should be targeted for structural, policy and individual‐level interventions to reduce racial disparities. [ABSTRACT FROM AUTHOR]

Human immunodeficiency virus (HIV) drug resistance is a major threat to the sustained impact of antiretroviral therapy (ART). We studied the epidemiology of drug resistance in the country of Georgia. The study included all adult patients who experienced virologic failure on first line ART and received HIV drug resistance testing between 2005 and 2016. The Stanford HIV Sequence Database was used for interpretation of the resistance data. Patient‐level data were extracted from the national AIDS health information system. Of the 447 patients included, 85.5% harbored the subtype A6 virus, 8.0% – subtype B, 2.9% – subtype G, and other subtypes were <1%. The most frequent first‐line regimens were Tenofovir/Emtricitabine/Efavirenz (28.4%), Zidovudine/Lamivudine/Efavirenz (28.4%), and Abacavir/Lamivudine/Efavirenz (15.9%). A total of 85.0% of the patients with treatment failure developed at least one drug resistance mutation affecting their susceptibility to ART. The most frequent nucleoside reverse transcriptase inhibitor mutations were M184V (65.3%), K65R (19.7%) and L74V (17.0%). At least three thymidine analogue mutations were detected in 6.3% of the patients. From non‐nucleoside reverse transcriptase inhibitor mutations, G190S was shown to be the most prevalent (49.4%), followed by K101E (27.10%) and K103N (24.4%). G190S and K101E were more common in subtype A as compared with non‐A viruses (G190S: 54.9% vs 11.3%, P < 0.0001; K101E: 29.8% vs 11.3%, P = 0.005). On the other hand, K103N was more frequent in non‐A subtypes (43.4%) compared with subtype A (22.2%), P = 0.0008. A majority of persons failing on ART had HIV drug resistance. Drug resistance patterns may vary by subtype. K65R mutation remains below 20%, but given the high use of Tenofovir in the country, continuing surveillance of drug resistance is needed. [ABSTRACT FROM AUTHOR]

Introduction: The transition from paediatric to adult HIV care is a particularly high-risk time for disengagement among young adults; however, empirical data are lacking. Methods: We reviewed medical records of 72 youth seen in both the paediatric and the adult clinics of the Grady Infectious Disease Program in Atlanta, Georgia, USA, from 2004 to 2014. We abstracted clinical data on linkage, retention and virologic suppression from the last two years in the paediatric clinic through the first two years in the adult clinic. Results: Of patients with at least one visit scheduled in adult clinic, 97% were eventually seen by an adult provider (median time between last paediatric and first adult clinic visit = 10 months, interquartile range 2-18 months). Half of the patients were enrolled in paediatric care immediately prior to transition, while the other half experienced a gap in paediatric care and re-enrolled in the clinic as adults. A total of 89% of patients were retained (at least two visits at least three months apart) in the first year and 56% in the second year after transition. Patients who were seen in adult clinic within three months of their last paediatric visit were more likely to be virologically suppressed after transition than those who took longer (Relative risk (RR): 1.76; 95% confidence interval (CI): 1.07-2.9; p = 0.03). Patients with virologic suppression (HIV-1 RNA below the level of detection of the assay) at the last paediatric visit were also more likely to be suppressed at the most recent adult visit (RR: 2.3; 95% CI: 1.34-3.9; p = 0.002). Conclusions: Retention rates once in adult care, though high initially, declined significantly by the second year after transition. Pre-transition viral suppression and shorter linkage time between paediatric and adult clinic were associated with better outcomes post-transition. Optimizing transition will require intensive transition support for patients who are not virologically controlled, as well as support for youth beyond the first year in the adult setting. [ABSTRACT FROM AUTHOR]

Because a broad spectrum of resource use allows species to persist in a wide range of habitat types, and thus permits them to occupy large geographical areas, and because broadly distributed species have access to more diverse resource bases, the resource breadth hypothesis posits that the diversity of resources used by organisms should be positively related with the extent of their geographic ranges., We investigated isotopic niche width in a small radiation of South American birds in the genus Cinclodes. We analysed feathers of 12 species of Cinclodes to test the isotopic version of the resource breadth hypothesis and to examine the correlation between isotopic niche breadth and morphology., We found a positive correlation between the widths of hydrogen and oxygen isotopic niches (which estimate breadth of elevational range) and widths of the carbon and nitrogen isotopic niches (which estimates the diversity of resources consumed, and hence of habitats used). We also found a positive correlation between broad isotopic niches and wing morphology., Our study not only supports the resource breadth hypothesis but it also highlights the usefulness of stable isotope analyses as tools in the exploration of ecological niches. It is an example of a macroecological application of stable isotopes. It also illustrates the importance of scientific collections in ecological studies. [ABSTRACT FROM AUTHOR]

In the Falkland Islands, islands with invasive rats have fewer passerine species compared to islands without rats. On islands on which rats have been eradicated, passerine species richness is indistinguishable from that found on islands historically free of rats, but community composition differs between these two island types. In particular, the most dominant species on historically rat-free islands, Cinclodes antarcticus, is less abundant and prevalent on eradicated islands. We compared passerine energy flow on islands with rats, islands from which rats have been eradicated, and islands on which rats were historically absent. Passerine communities on islands historically without rats used nine times more energy than on islands with rats present. Despite equivalent passerine species richness, passerine energy flow was approximately half on islands from which rats had been eradicated compared to historically rat-free islands. Because passerine energy flow was determined by community composition and not by species richness, passerine species within this community appear to be functionally complementary and not functionally redundant. At least one species, C. antarcticus, plays an irreplaceable role. Our results also document the dramatic and lingering effects of invasive species following their eradication, and the importance of species complementarity for the resilience of community properties. [ABSTRACT FROM AUTHOR]

Norway rats ( Rattus norvegicus) were introduced to the Falkland Islands and are detrimental to native passerines. Rat eradication programmes are being used to help protect the avifauna., This study assesses the effectiveness of eradication programmes while using this conservation practice as a natural experiment to explore the ecological resistance, resilience and homeostasis of bird communities., We conducted bird surveys on 230 islands: 85 in the presence of rats, 108 that were historically free of rats and 37 from which rats had been eradicated. Bird detection data were used to build occupancy models for each species and estimate species-area relationships. Count data were used to estimate relative abundance and community structure., Islands with invasive rats had reduced species richness of passerines and a different community structure than islands on which rats were historically absent. Although the species richness of native passerines was remarkably similar on eradicated and historically rat-free islands, community structure on eradicated islands was more similar to that of rat-infested islands than to historically rat-free islands., The results suggest that in the Falkland Islands, species richness of passerines is not resistant to invasive rats, but seems to be resilient following their removal. In contrast, community structure seems to be neither resistant nor resilient. From a conservation perspective, rat eradication programmes in the Falkland Islands appear to be effective at restoring native species richness, but they are not necessarily beneficial for species of conservation concern. For species that do not recolonize, translocations following eradications may be necessary. [ABSTRACT FROM AUTHOR]

J Oral Pathol Med (2012) 41: 288-291 Background: Oral human papillomavirus (HPV) is associated with several health complications especially in combination with HIV infections. Screening may be useful, but methodologies and results have varied widely in previous studies. We conducted a pilot study in an HIV-positive population to evaluate HPV detection in four different oral sample types. Methods: Upon enrollment, an oral-rinse (OR) sample was collected in 10 ml saline. Additional samples of the buccal mucosa, tonsils, and oral lesion if present were collected with cytology brushes. DNA was extracted using LC-MagNAPure, and the Linear Array HPV genotyping Assay (Roche) was used for HPV genotyping. Results: In samples from 100 HIV-positive participants, HPV was detected in 39 (%) of the oral rinses, 13 (%) mucosal and 11 (12.9%) tonsil brushings. Of seven lesion brushings collected, four were HPV positive. All participants with HPV detected in mucosal, tonsil, or lesion brushings were also positive in the OR sample. Among the rinse samples, 27 different genotypes were detected with HPV84 ( n = 6), HPV55 ( n = 5), and HPV83 ( n = 5) being the most common. Multiple infections were detected in 17 samples (range 2-9, mean 1.9 types). As potential cofactors, only receptive oral sex was significantly associated with HPV ( P = 0.018, odds ratio 2.9, 95% CI 1.2-6.9). Conclusion: Sampling is a significant factor for oral prevalence studies. Oral rinse provides the best representation for HPV in the oral cavity. To evaluate associated cofactors other than receptive oral sex, larger studies with case-control design are necessary. [ABSTRACT FROM AUTHOR]

Summary 1. Further advancement in the use of stable isotope analysis in animal ecology and physiology requires a better understanding of how organisms incorporate the macromolecular elements they consume into the tissues they biosynthesize. 2. Mixing models used to infer diets from isotopic data assume that assimilated macromolecules are dissembled into elements and then reassembled in animal tissues. 3. To test this assumption, we fed Nile tilapia diets with contrasting levels of protein and in which the carbon isotopic composition of protein differed from that of other macronutrients (carbohydrates and lipids). We then analysed the δ13C values of individual tilapia amino acids using compound-specific stable isotope analysis (CSIA). 4. The incorporation of dietary protein carbon was dependent on dietary protein content and on each amino acid's biosynthesis pathway. The δ13C values of glycolytic amino acids, such as glycine, serine and alanine, had roughly constant values that reflected a large contribution of dietary carbohydrates and a small contribution of dietary protein. The δ13C values of aspartate and glutamate that are biosynthesized from Krebs cycle intermediaries paralleled bulk diet. 5. The δ13C values of indispensable amino acids resembled that of carbohydrates at low protein intakes but tended asymptotically to that of the δ13C values of their corresponding dietary amino acid as protein intake increased. This pattern is consistent with assimilation of indispensable amino acids of microbial origin by tilapias fed low protein food. 6. Our results suggest that the assumptions of mixing models are sound in situations where omnivores consume protein-deficient diets, as the elemental constituents used to biosynthesize amino acids in tissues may be derived from various ingested macromolecules (e.g. protein, carbohydrates, or lipids) and their elemental components. In contrast, for omnivores that consume sufficient amounts of protein, macromolecular (e.g. protein) routing likely occurs and mixing model assumptions are violated. 7. Our study shows that CSIA is a novel method to quantify the contribution of symbiotic microbes to the amino acid homeostasis of animals. [ABSTRACT FROM AUTHOR]

1. We propose a new model that uses an organism’s change in mass to estimate isotope incorporation rates. Our model is a re-parameterization of a widely used one-compartment-first-order kinetic model that estimates the rate of isotopic incorporation as a function of time. If animals are growing exponentially and fractional growth rates are measured, the time model allows partitioning the contribution of growth and catabolic turnover to isotopic incorporation. The model can be extended to include more than one-compartment. 2. Our model makes the same assumptions but uses mass change as an independent variable. It estimates the ratio of the contribution of catabolic turnover to growth. 3. To test the model, we fed juvenile Nile tilapia ( Oreochromis niloticus) at three different rations and measured their change in mass and tissue δ13C isotopic composition for 128 days. 4. Fish grew exponentially and fractional growth rates differed significantly between rations. The contribution of catabolism (tissue replacement) to isotopic incorporation was 2·6 to 5 times higher than growth (tissue addition) in liver. In muscle tissue, the contribution of catabolism and growth were roughly equivalent for all rations. 5. When we used the parameters of the mass model to re-parameterize the time model we found a relatively good fit ( r2 = 0·8 ± 0·1, mean ± SD) to the isotopic incorporation data. 6. The mass model estimated a smaller, and more biologically realistic range of δ∞ values than did the time model which suggests that it might yield better results when isotopic incorporation experiments are not carried on long enough to yield estimates of the asymptotic isotopic value of an animal’s tissues after a diet shift. 7. Rather than being alternatives, the time and mass models are complementary in that they allow us to see the same phenomenon from different perspectives. [ABSTRACT FROM AUTHOR]

Seed dispersal has a powerful influence on population dynamics, genetic structuring, evolutionary rates, and community ecology. Yet, patterns of seed dispersal are difficult to measure due to methodological shortcomings in tracking dispersed seeds from sources of interest. Here we introduce a new method to track seed dispersal: stable isotope enrichment. It consists of leaf-feeding plants with sprays of 15N-urea during the flowering stage such that seeds developed after applications are isotopically enriched. We conducted a greenhouse experiment with Solanuin aniericanu,n and two field experiments with wild Capsicum annuuin in southern Arizona, USA, to field-validate the method. First, we show that plants sprayed with 15N-urea reliably produce isotopically enriched progeny, and that δ15N (i.e., the isotopic ratio) of seeds and seedlings is a linear function of the 15N-urea concentration sprayed on mothers. We demonstrate that three urea dosages can be used to distinctly enrich plants and unambiguously differentiate their offspring after seeds are dispersed by birds. We found that, with high urea dosages, the resulting δ15N values in seedlings are 103-104 times higher than the δ15N values of normal plants. This feature allows tracking not only where seeds arrive, but in locations where seeds germinate and recruit, because δ15N enrichment is detectable in seedlings that have increased in mass by at least two orders of magnitude before fading to normal δ15N values. Last, we tested a mixing model to analyze seed samples in bulk. We used the δ15N values of batches (i.e., combined seedlings or seeds captured in seed traps) to estimate the number of enriched seeds coming from isotopically enriched plants in the field. We confirm that isotope enrichment, combined with batch-sampling, is a cheap, reliable, and user-friendly method for bulk-processing seeds and is thus excellent for the detection of rare dispersal events. This method could further the study of dispersal biology, including the elusive, but critically important, estimation of long-distance seed dispersal. [ABSTRACT FROM AUTHOR]

About 10 years ago, reviews of the use of stable isotopes in animal ecology predicted explosive growth in this field and called for laboratory experiments to provide a mechanistic foundation to this growth. They identified four major areas of inquiry: (1) the dynamics of isotopic incorporation, (2) mixing models, (3) the problem of routing, and (4) trophic discrimination factors. Because these areas remain central to isotopic ecology, we use them as organising foci to review the experimental results that isotopic ecologists have collected in the intervening 10 years since the call for laboratory experiments. We also review the models that have been built to explain and organise experimental results in these areas. [ABSTRACT FROM AUTHOR]

1. Ten years ago Gannes et al. (1997 , Stable isotopes in animal ecology: assumptions, caveats, and a call for laboratory experiments. Ecology, 78, 1271–1276, 1998) identified four major areas requiring further research in experimental animal isotopic ecology: (i) the dynamics of isotopic incorporation, (ii) mixing models, (iii) the problem of routing, and (iv) trophic discrimination factors. 2. Differences in isotopic incorporation rates among tissues seem to be explained by variation in protein turnover. The application of multi-compartment models to isotopic incorporation data has revealed that different inferences can be derived between these and one-compartment models. 3. A variety of mixing models of varying degrees of complexity and realism are used to find the contribution of isotopic sources to the elements in an organism's tissues. The use of these models demands the use of tissue to diet discrimination factors that are rarely measured experimentally. 4. Mixing models assume that assimilated nutrients are disassembled into their elemental components and that these elements are reassembled into biomolecules. This assumption is unrealistic as macromolecules are routed differentially into tissues. Isotopic routing is an area that isotopic ecologists have neglected in their experimental and modelling research. 5. Isotopic ecologists are just beginning to understand why 15N biomagnifies along trophic chains, and to explore the factors that determine the degree of 15N biomagnification. We review the hypotheses that explain why 15N biomagnifies up trophic chains. 6. The use of compound-specific isotopic analyses is opening new fruitful areas of research at the intersection of nutritional and isotopic ecology. [ABSTRACT FROM AUTHOR]

Parasympathetic activity during acute coronary artery occlusion (CAO) can protect against ischaemia-induced malignant arrhythmias; nonetheless, the mechanism mediating this protection remains unclear. During CAO, myocardial electrotonic uncoupling is associated with autonomically mediated immediate (i.e. type 1A) arrhythmias and can modulate pro-arrhythmic dispersion of repolarization. Therefore, the effects of acutely enhanced or decreased cardiac parasympathetic activity on early electrotonic coupling during CAO, as measured by myocardial electrical impedance (MEI), were investigated. Anaesthetized dogs were instrumented for MEI measurements, and left circumflex coronary arterial occlusions were performed in intact (CTRL) and vagotomized (VAG) animals. The CAO was followed by either vagotomy (CTRL) or vagal nerve stimulation (VNS, 10 Hz, 10 V) in the VAG dogs. Vagal nerve stimulation was studied in two additional sets of animals. In one set heart rate (HR) was maintained by pacing (220 beats min−1), while in the other set bilateral stellectomy preceded CAO. The MEI increased after CAO in all animals. A larger MEI increase was observed in vagotomized animals (+85 ± 9 Ω, from 611 ± 24 Ω, n= 16) when compared with intact control dogs (+43 ± 5 Ω, from 620 ± 20 Ω, n= 7). Acute vagotomy during ischaemia abruptly increased HR (from 155 ± 11 to 193 ± 15 beats min−1) and MEI (+12 ± 1.1 Ω, from 663 ± 18 Ω). In contrast, VNS during ischaemia ( n= 11) abruptly reduced HR (from 206 ± 6 to 73 ± 9 beats min−1) and MEI (−16 ± 2 Ω, from 700 ± 44 Ω). These effects of VNS were eliminated by pacing but not by bilateral stellectomy. Vagal nerve stimulation during CAO also attenuated ECG-derived indices of ischaemia (e.g. ST segment, 0.22 ± 0.03 versus 0.15 ± 0.03 mV) and of rate-corrected repolarization dispersion [terminal portion of T wave (TPEc), 84.5 ± 4.2 versus 65.8 ± 5.9 ms; QTc, 340 ± 8 versus 254 ± 16 ms]. Vagal nerve stimulation during myocardial ischaemia exerts negative chronotropic effects, limiting early ischaemic electrotonic uncoupling and dispersion of repolarization, possibly via a decreased myocardial metabolic demand. [ABSTRACT FROM AUTHOR]

1. Insects are frequently sampled in food web studies and are assumed to follow the pattern of enrichment in 15N across trophic levels observed for other organisms. However, few studies have examined 15N discrimination of metamorphosing insects. 2. We measured the δ15N of larvae, pupae and adults of four Lepidoptera ( Bombyx mori, Galleria mellonella, Manduca sexta and Vanessa cardui), one Diptera ( Sarcophaga sp.) and one Coleoptera ( Tenebrio molitor) fed on artificial diets. 3. The tissues of larvae were enriched in 15N relative to their diet and this enrichment was explained by the production of 15N-depleted frass. Surprisingly, the tissues of adults were enriched in 15N relative to larvae in all but one species ( T. molitor). Because, we measured the tissues of adults immediately after they emerged from pupal cases, the enrichment was not due to a change in diet. Rather, it was due to the excretion of 15N depleted metabolic waste (‘meconium’) that resulted from protein metabolism during metamorphosis. 4. To our knowledge, the 15N enrichment that seems to accompany metamorphosis in holometabolous insects had not been previously recognized. This enrichment must be accounted for in ecological studies that rely on stable isotopes to identify both the trophic position and diet of insects. [ABSTRACT FROM AUTHOR]

An experimental investigation about the Circular In-Phase Hybrid Ring power divider is presented. This device is a Five Ports Hybrid Ring that has potential applications in Antenna Array feeding Networks. Its principal behavior characteristics are analyzed and compared with a conventional device. A prototype, which includes the effects of SMA connectors, was designed and measured corroborating the behavior of this circuit as a conventional five ports microstrip hybrid. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2314–2317, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22714 [ABSTRACT FROM AUTHOR]

1. A major paradigm shift is occurring in the approach of ecologists to statistical analysis. The use of the traditional approach of null-hypothesis testing has been questioned and an alternative, model selection by information–theoretic methods, has been strongly promoted and is now widely used. For certain types of analysis, information–theoretic approaches offer powerful and compelling advantages over null-hypothesis testing.2. The benefits of information–theoretic methods are often framed as criticisms of null-hypothesis testing. We argue that many of these criticisms are neither irremediable nor always fair. Many are criticisms of the paradigm's application, rather than of its formulation. Information–theoretic methods are equally vulnerable to many such misuses. Care must be taken in the use of either approach but users of null-hypothesis tests, in particular, must greatly improve standards of reporting and interpretation.3. Recent critiques have suggested that the distinction between experimental and observational studies defines the limits of the utility of null-hypothesis testing (with the paradigm being applicable to the former but not the latter). However, we believe that there are many situations in which observational data are collected that lend themselves to analysis under the null-hypothesis testing paradigm. We suggest that the applicability of the two analytical paradigms is more accurately defined by studies that assess univariate causality (when null-hypothesis testing is adequate) and those that assess multivariate patterns of causality (when information–theoretic methods are more suitable).4. Synthesis and applications. Many ecologists are confused about the circumstances under which different inferential paradigms might apply. We address some of the major criticisms of the null-hypothesis testing paradigm, assess those criticisms in relation to the information–theoretic paradigm, propose methods for improving the use of null-hypothesis testing, and discuss situations in which the use of null-hypothesis testing would be appropriate. We urge instructors and practitioners of statistical methods to heighten awareness of the limitations of null-hypothesis testing and to use information–theoretic methods whenever prior evidence suggests that multiple research hypotheses are plausible. We contend, however, that by marginalizing the use of null-hypothesis testing, ecologists risk rejecting a powerful, informative and well-established analytical tool.Journal of Applied Ecology(2005)42, 4 –12doi: 10.1111/j.1365-2664.2005.01002.x [ABSTRACT FROM AUTHOR]

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Summary 1. Specialised nectar-feeding birds tend to prefer sucrose over glucose-fructose mixtures or to be indifferent when tested at concentrations close to 584 mmol L-1 sucrose equivalents. The role of the potential interaction between sugar composition and concentration on the sugar preferences of these birds, however, has not been explored. 2. We tested the hypothesis that sugar preferences in nectar-feeding birds are concentration-dependent. We predicted that at high concentrations they would prefer sucrose over hexoses, whereas at low sugar concentrations they would prefer hexoses. We expected birds to show differences in food intake that matched their sugar preferences when they fed on equicaloric solutions of sucrose and 1 : 1 mixture of glucose and fructose. Consequently, the curves describing the relationship between food intake and sugar concentration for these two sugar solutions should cross. We tested these hypotheses in two species of nectar-feeding birds: the Cinnamon-bellied Flowerpiercer, Diglossa baritula (Wagler) and the Magnificent Hummingbird, Eugenes fulgens (Swainson). 3. The sugar preferences of both species were concentration dependent. At lower concentrations they preferred hexoses, whereas at higher concentrations they shifted their preference to sucrose. However, these concentration-dependent preferences were not matched by parallel differences in intake. 4. Although nectar composition and concentration are often discussed as two different floral traits, our results show that they have a synergistic effect on the sugar preferences of nectar-feeding birds. [ABSTRACT FROM AUTHOR]

The physiological traits that allow fish to survive periods of limited food resources are poorly understood. We assessed changes in proximate body composition, relative organ mass, blood metabolites, and relative weight ( Wr) of sedentary and actively swimming (15 cm/s) juvenile rainbow trout (154-182 mm total length) over 147 d of fasting. Fasting caused measurable responses that were augmented when fish were swimming. Lipids and plasma triacylglycerides declined over time. Proteins were catabolized simultaneously with lipid reserves, but ammonia concentrations in plasma did not increase. The liver somatic index (LSI) did not change substantially over 105 d, suggesting that gluconeogenesis maintained blood glucose concentrations and hepatic glycogen reserves for a substantial period of fasting. The gut somatic index (GSI) and Wr declined linearly during fasting, but the LSI did not decline until after 105 d of fasting. Consequently, the use of different body condition indices could lead to different conclusions about the condition of juvenile rainbow trout. Swimming activity caused fish to have lower lipid and protein reserves than those of sedentary fish. No mortalities were observed among sedentary fish, but mortalities occurred among actively swimming fish after 97 d of fasting when 3.2% or less lipid remained in their bodies. Body condition indices did not account for differences in proximate body composition between sedentary and actively swimming fish and were relatively poor predictors of lipid content and risk of mortality. The probability of mortality was most accurately predicted by percent lipid content. Therefore, we suggest that fisheries scientists consider using percent lipid content when evaluating the physiological status and risk of mortality due to starvation among juvenile rainbow trout. [ABSTRACT FROM AUTHOR]

The distribution of desert mistletoes (Phoradendron californicum) among mesquite (Prosopis velutina) hosts is significantly aggregated. We hypothesized that the aggregation of mistletoes among hosts is produced by the pattern of seed rain generated by seed dispersers. We tested whether frugivorous Phainopeplas (Phainopepla nitens) foraged preferentially, and hence deposited mistletoe seeds disproportionately, in already parasitized mesquites. We found that Phainopeplas favored parasitized tall trees as perching and feeding sites and deposited mistletoe seeds disproportionately on trees with these characteristics. To assess experimentally the effect of the presence of mistletoes on seed deposition, we removed mistletoes from host trees. Before mistletoe removal, seed deposition was equivalent and temporally correlated in pairs of control and removal trees. After removal, deposition was lower into removal trees than into unmanipulated trees. Although mistletoe removal resulted in lower seed deposition, it did not eliminate it. We inferred that seed deposition into parasitized hosts can result from deposition of seeds originating from within a host and from other infected hosts. We conclude that the response of seeddispersing birds to mistletoes leads to disproportionate seed deposition into already parasitized trees and that the heterogeneous distribution of seeds among hosts created by birds contributes to the clumped distribution of mistletoes among hosts. [ABSTRACT FROM AUTHOR]

Examines the importance of saguaro fruit for desert dove species in the U.S. Description of the saguaro cactus; Production of water and nutrient source for desert animals; Incorporation of saguaro carbon into dove tissues.

In this paper, a new implementation of rectangular waveguide filters using dielectric periodic structures called electromagnetic crystals is presented. By tuning its forbidden band with the desired rejection band of the rectangular waveguide, the filtering behavior is obtained. The dependence of the filter features as a function of the periodic structure characteristics is shown. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 81–84, 2001. [ABSTRACT FROM AUTHOR]

ABSTRACT Genomic resources are valuable to examine historical demographic patterns and their effects to better inform management and conservation of threatened species. We evaluated population trends and genome‐wide variation in the near‐threatened Orange‐breasted Falcon (Falco deiroleucus) and its more common sister species, the Bat Falcon (F. rufigularis), to explore how the two species differ in genomic diversity as influenced by their contrasting long‐term demographic histories. We generated and aligned whole genome resequencing data for 12 Orange‐breasted Falcons and 9 Bat Falcons to an annotated Gyrfalcon (F. rusticolus) reference genome that retained approximately 22.4 million biallelic autosomal SNPs (chromosomes 1–22). Our analyses indicated much lower genomic diversity in Orange‐breasted Falcons compared to Bat Falcons. All sampled Orange‐breasted Falcons were significantly more inbred than the sampled Bat Falcons, with values similar to those observed in island‐mainland species comparisons. The distribution of runs of homozygosity showed variation suggesting long‐term low population size and the possibility of bottlenecks in Orange‐breasted Falcons contrasting with consistently larger populations in Bat Falcons. Analysis of genetic load suggests that Orange‐breasted Falcons are less likely to experience inbreeding depression than Bat Falcons due to reduced inbreeding load but are at elevated risk from fixation of deleterious gene variants and perhaps a reduced adaptive potential. These genomic analyses highlight differences in the historical demography of two closely related species that have influenced their current genomic diversity and should result in differing strategies for their continued conservation. [ABSTRACT FROM AUTHOR]

Compares the efficiency with which phyllostomid bats with different degrees of flower specialization extract the contents of three species of pollen. Excretion patterns and chemical reactor models; Pollen extraction and processing time; Differences in pollen digestive processing between species of bats that regularly feed on pollen.

The author reflects on the significance of researches about human microbiome. He states that researches on microorganisms including bacteria, Archaea, and fungi found on human bodies are significant in understanding human health. He mentions that every human has more than 100 trillion microbial symbionts. He suggests that studies conducted on human microbiome be also applied in to meet the challenges of conservation of native plant and animal life.

The article focuses on the response to the authors' call for statistical pluralism in inferential approaches. They state that the critics have clarified the arguments on statistical approaches while offering clarification on theoretic approaches. Despite the clarification, the authors emphasize the ciritcs' confusing scientific study on algorithm and their overstated analysis on this rule. Also, the critics' characterization of null hypothesis process, the use of highly simplistic example for illustrative purposes and their method of developing a scientific hypothesis are criticized.

Comments on the feasibility of the ethical research in developed and developing countries as discussed in the paper `The Ethics of HIV Research in Developing Nations,' by David B. Resnik. Information on HIV epidemic in developing countries; Ethics of the use of placebo-controlled trials in the prevention of perinatal transmission of HIV; Debate on research ethics guidelines.

While several studies have shown that invasive rats can have negative effects on island birds through predation (both direct predation and nest predation), other mechanisms for the effects of invasives on island biota have been given less attention. Here, we explore another potential mechanism by which invasive rats can affect native island birds: the competitive use of common resources. We used stable isotope analyses to estimate the fraction of marine and terrestrial sources incorporated into the tissues of two species of passerines ( Troglodytes cobbi, Troglodytidae; and Cinclodes antarcticus, Furnariidae) and Norway rats ( Rattus norvegicus, Muridae) in the Falkland Islands. These two passerines are absent on islands where rats are present. We found significant incorporation of marine resources in the three species, with the highest incorporation in tissues of T. cobbi. This species appears to be one of the passerines most reliant on marine sources and the most marine member of the family Troglodytidae. We also used the results of these isotopic analyses to estimate the isotopic niche breadth of each of these species and the isotopic niche overlap among them. Rattus norvegicus had a large isotopic niche that overlapped broadly with those of the two passerine species. We propose that different ways of both depicting and estimating isotopic niche widths are complementary rather than alternative. Our results are consistent with the notion that invasive rats might have an impact on these two species of Falkland Island passerines by using common resources but do not rule out the possibility that part of their effect is through direct predation. [ABSTRACT FROM AUTHOR]

A potential mechanism for ventricular fibrillation (VF) and sudden cardiac death following myocardial infarction (MI) is the remodeling of repolarization currents, leading to increased action potential duration and dispersion of repolarization. Recently, it has been shown in vitro that electrotonic loading, resulting from, heterogeneities in the ventricle, triggers the remodeling of the current. Thus, we studied electrotonic coupling in the post-MI heart, as measured by myocardial electrical impedance (MEI). Infarcts were induced in dogs by LAD coronary artery ligation. The dogs were instrumented with MEI electrodes in normal (LCX and LAD) and infarcted myocardium. After recovery, MEI was measured in awake-unsedated animals 1, 2, and 7 days after MI. Subsequently, VF-susceptibility was tested by a 2-min LCX occlusion during submaximal exercise; 11 animals developed VF (susceptible, S) and 10 did not (resistant, R). Healing myocardial infarct had significantly lower MEI than normal myocardium (see figure). This difference was steady by day 2 post-MI (287±8.5 vs. 425±16.7 Ω, ANOVA P<0.05). Furthermore, significant differences were observed between resistant and susceptible animals: One week after MI, susceptible dogs had a wider electrotonic disparity between remote myocardium and scar (R: 86.5±20.7 vs. S: 183.7±12.6 Ω, P<0.05). These data suggest that electrotonic remodeling following MI may contribute to malignant ventricular arrhythmias. [ABSTRACT FROM AUTHOR]

The article presents an explanation from the author of the journal "Functional Ecology," discussing the history and the reason for its similarity with the journal "Biological Reviews". The author mentions that some confusion led to the considerable degree of similarity between the two papers. "Functional Ecology," which is prepared keeping in mind a specific set of readers, is a shorter edition of "Biological Reviews," that presents a detailed description of animal isotopic ecology.

Utilizing a new echocardiographic system, intramyocardial coronary arteries could be demonstrated by color Doppler in a small number of open chest animals. Both intravenous and intracoronary injections of a contrast agent (Levovist) resulted in significant enhancement of color flow signals with an increase in the length, width, and the number of these vessels. Similar results were obtained with intravenous infusion and direct intracoronary injections of a vasodilator (adenosine). (ECHOCARDIOGRAPHY, Volume 13, November 1996)