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Understanding the regional diversity of epiphytic bryophytes along elevation gradients is crucial for assessing forest ecosystems, particularly in areas vulnerable to climate change. The study aimed to compare the composition and richness of epiphytic bryophytes colonising on basal trunks of Cryptomeria japonica, a predominant conifer in the Darjeeling hills, across different altitude zones, and to assess the underlying macroclimatic factors driving such variations. The field surveys were performed at nine elevation zones of Darjeeling between 1450 and 2250 m above sea level. Bryophytes belonging to 37 genera, primarily from Dicranales and Hypnales, were recorded. Diversity profiles reflected low evenness, with Syrrhopodon confertus emerging as the dominant moss in the community. Species richness displayed a multimodal pattern along the altitudinal gradient. The trend exhibited an initial hump peaking at 1550 m and a subsequent rise of richness above 2150 m. About 43.24% of species were confined to a single altitude zone, signifying a narrow range of occurrence. The epiphyte compositions of 1450, 1550 and 2250 m were distinct compared to the other elevation zones. Furthermore, statistical evaluation predicted the influence of climatic parameters such as precipitation, temperature stability and solar radiation on bryophyte assemblage. Therefore, the outcome provides a broad overview of the distribution of bryophytes at managed conifer forests and underscores the significance of elevation-specific climatic conditions in shaping bryophyte diversity, which can be useful for designing their effective conservation strategies.
Recently, autonomous aerial systems have received unparalleled popularity and applications as varied as they are innovative in the civil domain. The unmanned aerial vehicle (UAV) is now the subject of intensive research in both aeronautical and automotive engineering.
This paper presents a new, robust gain-scheduled adaptive control strategy for a class of UAV with linear parameter varying (LPV) models. The proposed controller synthesis involves a set of pre-tuned linear quadratic regulator (LQR) combined with fractional-order PID controllers supervised with an adaptive switching law. The main innovation in this work is the enhancement of the classical gain-scheduling adaptive control robustness for systems with LPV models by combining a set of robust LQR + fractional-order PID compensators. The stability of the resulting controller is demonstrated and its efficiency is validated using a numerical simulation example on a civilian UAV system airspeed and altitude control to illustrate its practical efficiency and achieved robustness.
Edited by
Alexandre Caron, Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), France,Daniel Cornélis, Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD) and Foundation François Sommer, France,Philippe Chardonnet, International Union for Conservation of Nature (IUCN) SSC Antelope Specialist Group,Herbert H. T. Prins, Wageningen Universiteit, The Netherlands
Based on genetics and ecology, it is best to discern three subspecies of African buffalo, namely the northern savanna buffalo, the Cape buffalo and the forest buffalo. In honour of the oldest written reference to the buffalo by the Syrian geographer Ibn Fadl Allah al-Umari in 1347 CE, we propose the name Syncerus caffer umarii for the northern savanna buffalo, and maintain S. c. caffer for the Cape buffalo and S. c. nanus for the forest buffalo. We think it likely that the forest buffalo is a recent form of buffalo (about 150 kyr), derived from the northern savanna buffalo in the eastern part of its range, which underwent dwarfing (i.e. miniaturization) in the rainforest. We propose that the northern savanna buffalo, because of the high amount of genetic exchange with the forest buffalo, has many hallmarks of a hybrid subspecies that expanded its range due to the creation of the Guinea savanna and Sudan savanna by Iron Age agriculturalists. The Cape buffalo shows the highest number of food web interactions with other large mammals, while the dwarfed forest buffalo is very lightly embedded in its trophic web.
Secondary sexual dimorphism (SSD) in flowering plants is expressed as differences in sexual characteristics that are not directly related to gamete production, involving a wide variety of morphological and physiological traits. Yerba mate (Ilex paraguariensis) is an evergreen dioecious tree native to South America. It was hypothesized that: (1) in early years, the two yerba-mate genders would segregate with lower frequency in biomass production than during later years; (2) in the case of SSD, higher biomass production would be seen for female plants when compared to male plants at a more advanced age; (3) higher SSD would appear in morphotypes that represent leaf adaptations to full sunlight cultivation; and (4) progenies originated from provenances from higher altitudes will show greater SSD in biomass production. One experiment with 135 progenies originated from six provenances with different altitudes was established in 1997 in a monoculture (under full sunlight conditions). Biomass production (leaves and thin twigs) per plant was evaluated during four harvests (1999, 2001, 2003, and 2015). The frequency of SSD in biomass production did not change throughout the plant’s life. Males were more productive than females in 1999, 2001, and 2003, while the increased frequency of more productive female plants was observed during the most recent harvest (2015), resulting in an equal frequency of female and male progenies. Sexual segregation was observed in dully green, sassafras, and gray morphotypes that are characterized by their waxy leaf structures, an adaptation to elevated irradiance and UV. As a result of adaptative responses to stressful conditions and elevated interplant variability, the relationship between SSD and biomass production of progenies originated from the highest altitudes segregated with higher frequency when compared to the lowest altitudes.
Bergmann’s Rule describes an increase in the body size of endothermic animals with decreasing environmental temperatures. However, in ectothermic insects including moths, some of the few existing studies investigating size patterns along temperature gradients do not follow the Bergmann’s Cline. Intraspecific differences in moth sizes along spatiotemporal temperature gradients are unknown from the Palaeotropics, hindering general conclusions and understanding of the mechanism responsible. We measured intraspecific forewing size differences in 28 Afrotropical moth species sampled in 3 seasons along an elevational gradient on Mount Cameroon, West/Central Africa. Size increased significantly with elevation in 14 species but decreased significantly in 5 species. Additionally, we found significant inter-seasonal size differences in 21 species. Most of these variable species had longer forewings in the transition from the wet to dry season, which had caterpillars developing during the coldest part of the year. We conclude that environmental temperature affects the size of many Afrotropical moths, predominantly following prevailingly following Bergmann’s Cline. Nevertheless, the sizes of one-third of the species demonstrated a significant interaction between elevation and season. The responsible mechanisms can thus be assumed to be more complex than a simple response to ambient temperature.
Access to care services in remote areas is challenging. The use of telemedicine technology in these areas facilitates access to health care. This study aimed to summarize the current research on telemedicine in remote areas such as mountains and forests. A systematic search was conducted in databases including Medline (through PubMed), Scopus, IEEE Xplore Digital Library, and ISI Web of Science to identify relevant studies published until May 12, 2021. Screening of retrieved articles for selection and inclusion in the study was performed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyzes extension for Scoping Reviews (PRISMA-ScR) checklist. A total of 807 articles were identified after removing duplicates, from which 20 studies meeting our inclusion criteria were selected. Challenges, opportunities, and equipment required to use telemedicine in remote areas were extracted from the selected studies. The results revealed that telemedicine implementation in remote areas had many challenges, including harsh weather conditions, Internet connectivity problems, difficult equipment transportation, and ethical issues. Telemedicine also has many benefits, such as cost and time savings for patients, improving patients’ quality of life, and improving patient satisfaction. Telemedicine for inhabitants of forested and mountainous areas facilitates rapid access to health care and enhances patient satisfaction. Distinguishing advantages and barriers as well as reducing restrictions will have an essential role in accelerating the use of this technology.
This chapter considers the observation, comparison and visual representation of a range of altitudinal limits in the Himalaya: plants, animals, crops and human habitation. These limits were addressed especially through the lens plant geography. The chapter begins by examining the absolute limits of vegetation and attempts to divide up the Himalaya using a vocabulary of verticality borrowed from the horizontal (tropical, temperate and arctic). The second section extends these debates to animals. The third section examines debates over the ‘tropicality’ of the Himalaya, and inconsistences in the line of perpetual snow. The fourth section considers the altitude limits of cultivation, firewood and human habitation. The final section considers attempts to represent and understand these altitude limits visually by considering charts made by William Griffith and Richard Strachey. The chapter argues that as much as from abstract scientific interests, observations of altitude thresholds were wrapped up with the concerns of empire. Ultimately, applying existing horizontal divisions meant simultaneously overwriting pre-existing local cosmologies, and broader South Asian imaginings.
Of the monkeys in Africa, the colobines comprise 19% of the 16 genera and 30% of the 79 species. They occur all across tropical African from sea level to 3,400 m above sea level, and where temperatures range from -7°C to 41°C and mean annual rainfall ranges from 50 cm to 1,100 cm. Ninety-six percent of the 24 species of Africa’s colobines are threatened with extinction, whereas 68% of the subspecies are threatened with extinction. Six of the species are ‘Critically Endangered’, including one that is probably already extinct. The two primary proximate threats to colobines in Africa are forest loss and hunting by humans, while the ultimate threat is humans and their widespread over-exploitation of natural resources. This chapter reviews the biological traits that make Africa’s colobines especially susceptible to extinction through forest loss and hunting, the threats they face, and the impacts of those threats. Predictions are presented concerning which species of African colobine will be among the first extinctions and where Africa’s colobines are expected to persist for at least the coming 30 years. Finally, this chapter presents an overview of the main conservation actions that Africa’s colobines require and gives priorities for research that will support their conservation.
It is difficult to expound in any pithy fashion on the imprint that James C. Scott's work has had on writing history in the orbit of Asia. Where to start? From The Moral Economy of the Peasant all the way to Against the Grain, Scott's work has found receptive and fertile ground among his peers in Asian studies, who have often proudly pointed out to their non-Asianist colleagues that Scott is “one of their own.” This has certainly been true “internally” as well, in the ways that Southeast Asianists have spoken to their fellow professionals in the larger, allied subdisciplines of South and East Asian studies. It does not matter that Scott's books have touched on a wide variety of subjects: the central concerns with power, agency, space, and the essence of a shared humanity have all resonated with his professional interlocutors.
Here, I consider the wide variety of habitats in which organisms live. Some are obviously conducive to life, such as a rainforest, while others are not, for example a black smoker in a mid-ocean trench. Wherever the habitat of a particular organism is, it can be divided into microhabitats, each of which differs in its array of constituent species. I distinguish between the place where an organism lives and the way it makes its living there. The latter is often referred to as the ecological niche, though care is needed with this term as it is used in different ways by different authors. I then focus on three particular examples of habitats to get a more in-depth view: the soil, hydrothermal vents, and the intertidal zone. Finally, I ask the question: to what extent should we expect habitats on exoplanets to have similar features to those on Earth? Considering the ubiquity of topography (on rocky planets) and of liquid water (on habitable-zone rocky planets), it seems reasonable to expect both aquatic and land-based habitats; the latter will generally be a mixture of high and low altitudes, as well as high and low latitudes.
In the first aerial crossing of the South Atlantic, by Gago Coutinho and Sacadura Cabral in 1922, several methods of astronomical maritime navigation were used with adaptions to aerial navigation. In order to apply these methods, the navigator needed to know the approximate altitude of the aircraft so that its position could be determined. The instrument available at that time, the altimeter, did not give reliable values for altitude. Therefore, Coutinho had to devise a method that enabled the navigator to determine the altitude quickly and efficiently. The method Coutinho devised is based on a mathematical and geometrical procedure. In this paper, we study in detail Coutinho's method to determine altitude, with diagrams to aid understanding of the deductions and calculations. We also present a real example of how this method would be used during the flight.
Seed reserves play vital roles in seed germination and seedling growth and their variation may be related to various environment factors, plant traits and phylogenetic history. Here, the evolutionary correlation associated with seed mass and altitude and carbon (C), nitrogen (N) and phosphorus (P) allocation of seeds among 253 alpine herbaceous plants was tested. In this study, phylogeny had strong limitations on nutrient allocation of seeds across species, and species from younger phylogenetic groups tended to have higher N and P contents, which might be considered as the evolutionary selection of seed plants. Higher seed N and P content would help seedlings to gain more survival chance and stronger competitive capacity, and their progeny would be more likely to be preserved. When phylogeny was considered, altitude only had a significant positive effect on P content, but the negative effects on seed mass were all expressed. The independent effects of altitude and seed mass suggest that the nutrient allocation of seeds might be affected by both environment and plant traits. In addition, altitude and seed mass displayed partial overlapping effects on nutrient allocation of seeds. The negative effects of seed mass were affected slightly by altitude, whereas altitude only had a significant positive effect on P content when seed mass was controlled. Above all, seed P content showed obvious and general correlations with seed mass, altitude and age of clade, which indicated that higher seed P content might be an adaptive selection of species associated with growth and survival of progeny.
Plant–animal mutualistic interactions through ecological network systems and the environmental conditions in which they occur, allow us to understand patterns of species composition and the structure and dynamics of communities. We evaluated whether flower morphologies with different pollination syndromes (ornithophilous and non-ornithophilous) are used by hummingbirds and whether these characteristics affect the structure (core-peripheral species) of hummingbird networks. Observations were made in flowering patches, where plant–hummingbird interactions were recorded at three altitudes (300–2500 m) during three seasons (dry, rainy and post-rainy) from 2015 to 2016 at El Triunfo Biosphere Reserve, Chiapas, Mexico. We recorded 15 hummingbird species interacting with 58 plant species, and the greatest number of interacting hummingbird species (11; 14) and plant species (28; 40) were found at middle altitudes and during the dry season, respectively. In all study sites, most of the plant species visited by hummingbirds had an ornithophilous syndrome (67%) at high altitudes (22 plant species) and during the dry season (26 plant species), but more individual hummingbirds visited non-ornithophilous plant species. The hummingbird species at high altitudes exhibited the greatest level of specialization towards plants (H2′ = 0.74), but the networks of plant-hummingbird interactions were generalist (H2′ = 0.25); i.e. visiting plants with both syndromes, at low altitudes. The core generalist hummingbird species remained constant with altitude and season, but the core generalist plant species varied between different altitudes and seasons according to the phenology of the species.
Psychotic episodes during exposure to very high or extreme altitude have been frequently reported in mountain literature, but not systematically analysed and acknowledged as a distinct clinical entity.
Methods
Episodes reported above 3500 m altitude with possible psychosis were collected from the lay literature and provide the basis for this observational study. Dimensional criteria of the Diagnostic and Statistical Manual of Mental Disorders were used for psychosis, and the Lake Louise Scoring criteria for acute mountain sickness and high-altitude cerebral oedema (HACE). Eighty-three of the episodes collected underwent a cluster analysis to identify similar groups. Ratings were done by two independent, trained researchers (κ values 0.6–1).
Findings
Cluster 1 included 51% (42/83) episodes without psychosis; cluster 2 22% (18/83) cases with psychosis, plus symptoms of HACE or mental status change from other origins; and cluster 3 28% (23/83) episodes with isolated psychosis. Possible risk factors of psychosis and associated somatic symptoms were analysed between the three clusters and revealed differences regarding the factors ‘starvation’ (χ2 test, p = 0.002), ‘frostbite’ (p = 0.024) and ‘supplemental oxygen’ (p = 0.046). Episodes with psychosis were reversible but associated with near accidents and accidents (p = 0.007, odds ratio 4.44).
Conclusions
Episodes of psychosis during exposure to high altitude are frequently reported, but have not been specifically examined or assigned to medical diagnoses. In addition to the risk of suffering from somatic mountain illnesses, climbers and workers at high altitude should be aware of the potential occurrence of psychotic episodes, the associated risks and respective coping strategies.
Intrauterine exposure to the rainy season in the tropics may be accompanied by high rates of infection and nutritional deficiencies. It is unknown whether this exposure is related to the extrauterine timing of development. Our aim was to evaluate the relations of prenatal exposure to the rainy season and altitude of residence with age at menarche. The study included 15,370 girls 10 to <18 years old who participated in Colombia’s 2010 National Nutrition Survey. Primary exposures included the number of days exposed to the rainy season during the 40 weeks preceding birth, and altitude of residence at the time of the survey. We estimated median menarcheal ages and hazard ratios with 95% confidence interval (CI) according to exposure categories using Kaplan–Meier cumulative probabilities and Cox proportional hazards models, respectively. All tests incorporated the complex survey design. Girls in the highest quintile of gestation days exposed to the rainy season had an earlier age at menarche compared with those in the lowest (adjusted hazard ratios (HR)=1.08; 95% CI 1.00–1.18, P-trend=0.03). Girls living at altitudes ⩾2000 m had a later age at menarche compared with those living <1000 m (adjusted HR=0.88; 95% CI 0.82–0.94, P-trend <0.001). The inverse association between gestation days during the rainy season and menarche was most apparent among girls living at altitudes ⩾2000 m (P, interaction=0.04). Gestation days exposed to the rainy season and altitude of residence were associated with the timing of sexual maturation among Colombian girls independent of socioeconomic status and ethnicity.
Objectives: Cognitive dysfunction from high altitude exposure is a major cause of civilian and military air disasters. Pilot training improves recognition of the early symptoms of altitude exposure so that countermeasures may be taken before loss of consciousness. Little is known regarding the nature of cognitive impairments manifesting within this critical window when life-saving measures may still be taken. Prior studies evaluating cognition during high altitude simulation have predominantly focused on measures of reaction time and other basic attention or motor processes. Memory encoding, retention, and retrieval represent critical cognitive functions that may be vulnerable to acute hypoxic/ischemic events and could play a major role in survival of air emergencies, yet these processes have not been studied in the context of high altitude simulation training. Methods: In a series of experiments, military aircrew underwent neuropsychological testing before, during, and after brief (15 min) exposure to high altitude simulation (20,000 ft) in a pressure-controlled chamber. Results: Acute exposure to high altitude simulation caused rapid impairment in learning and memory with relative preservation of basic visual and auditory attention. Memory dysfunction was predominantly characterized by deficiencies in memory encoding, as memory for information learned during high altitude exposure did not improve after washout at sea level. Retrieval and retention of memories learned shortly before altitude exposure were also impaired, suggesting further impairment in memory retention. Conclusions: Deficits in memory encoding and retention are rapidly induced upon exposure to high altitude, an effect that could impact life-saving situational awareness and response. (JINS, 2017, 23, 1–10)
Understanding the processes that shape parasite diversification, their distribution and abundance provides valuable information on the dynamics and evolution of disease. In this study, we assessed the diversity, distribution, host-specificity and infection patterns of apicomplexan parasites in amphibians and reptiles from Oman, Arabia. Using a quantitative PCR approach we detected three apicomplexan parasites (haemogregarines, lankesterellids and sarcocystids). A total of 13 haemogregarine haplotypes were identified, which fell into four main clades in a phylogenetic framework. Phylogenetic analysis of six new lankesterellid haplotypes revealed that these parasites were distinct from, but phylogenetically related to, known Lankesterella species and might represent new taxa. The percentage of infected hosts (prevalence) and the number of haemogregarines in the blood (parasitaemia) varied significantly between gecko species. We also found significant differences in parasitaemia between haemogregarine parasite lineages (defined by phylogenetic clustering of haplotypes), suggesting differences in host–parasite compatibility between these lineages. For Pristurus rupestris, we found significant differences in haemogregarine prevalence between geographical areas. Our results suggest that host ecology and host relatedness may influence haemogregarine distributions and, more generally, highlight the importance of screening wild hosts from remote regions to provide new insights into parasite diversity.