Hasil untuk "Natural history (General)"

R. C. Stebbins, Nathan W. Cohen

This is a book for all readers who want to learn about amphibians, the animal group that includes frogs, toads, salamanders, and caecilians. It draws on many years of classroom teaching, laboratory experience, and field observation by the authors. The authors explore some of nature's most interesting creatures, interspersing their own observations throughout the book. The book can serve as a textbook for students and independent learners, as an overview of the field for professional scientists and land managers, and as an introduction for general readers. The class Amphibia contains more than 4500 known living species. New species are being discovered so rapidly that the number may grow to more than 5000 during our lifetimes. However, their numbers are being rapidly diminished around the globe, largely due to the encroachment of humans on amphibian habitats and from growing human-caused environmental pollution, discussed at length in the final chapter. The authors focus our attention on the "natural history" of amphibians world-wide and emphasize their interactions with their environments over time: where they live; how they reproduce; how they have been affected by evolutionary processes; what factors will determine their destinies over time.

Vasileios Lekakis, G. Papatheodoridis

Metabolic dysfunction-associated steatotic liver disease (MASLD), which has been the term for non-alcoholic fatty liver disease (NAFLD) since June 2023, represents the most common liver disease worldwide and is a leading cause of liver-related morbidity and mortality. A thorough knowledge of the disease's natural history is required to promptly stratify patients' risks, since MASLD is a multifaceted disorder with a broad range of clinical phenotypes. The histological disease spectrum ranges from isolated hepatic steatosis, currently named as metabolic dysfunction-associated steatotic liver (MASL), to metabolic dysfunction-associated steatohepatitis (MASH) and eventually may accumulate hepatic fibrosis and develop cirrhosis and/or hepatocellular carcinoma (HCC). Several risk factors for fibrosis progression have been identified, while the disease's progression displays notable dynamism and bidirectionality. When compared to the general population, all MASLD histological stages are substantially related with greater overall mortality, and this association exhibits a disease severity-dependent pattern. Interestingly, the fibrosis stage is the most accurate predictor of mortality among MASLD patients. The mortality attributed to MASLD predominantly stems from issues linked with the liver and cardiovascular system, as well as HCC and extrahepatic cancers. In light of the disease natural course, it is crucial to prioritize the identification of at-risk patients for disease progression in order to effectively address and change modifiable risk factors, hence mitigating disease complications. Further investigation is required to define the phenotype of rapid progressors more precisely as well as to improve risk stratification for HCC in non-cirrhotic individuals.

Meryem Mojtahid, Magali Schweizer, Damien Le Moigne et al.

This paper presents the results of a dual approach for assessing fossil benthic foraminiferal communities using both traditional morphology‐based analyses and sedimentary ancient DNA (sedaDNA) metabarcoding. The main objectives are to test the feasibility of sedaDNA analyses to assess foraminiferal biodiversity in temperate shelf sediments (Le Croisic, France) off a major river system through time (Mid‐ to Late Holocene), and to point out the similarities and differences between classical and molecular methods. Our results show that, in contrast to the high foraminiferal diversity obtained from classic morphological analysis (over 140 taxa), the sedaDNA analysis yielded only 20 operational taxonomic units (OTUs), which can be considered as equivalent to species. This strongly suggests a bad preservation of foraminiferal DNA downcore, likely due to the relatively ‘high’ temperature of the study site (14 °C) and/or to a methodological bias (e.g. insufficient amount of extracted sediment). In the total sedaDNA, more than 90% of the reads were assigned to monothalamids (organic‐shelled foraminifera). In contrast, only a small number of mineralized taxa, highly dominant when identified using the morphological approach, were detected. This could be due to the naturally higher abundance of monothalamids compared to hard‐shelled foraminifera. While this abundance is reflected in sedaDNA, it is not preserved in fossil morphological assemblages. In addition, the sedaDNA of monothalamids might be easier to extract and their barcode to amplify than hard‐shelled foraminifera. The discrepancies between the microfossil data and sedaDNA also include several species (e.g. Ammonia confertitesta (T6), Elphidium oceanense (S3), Nonionella sp. T4 and Nonionella sp. T6) that were rarely or not at all found in the fossil material which might be an indication of the presence of propagules, morphologically undetected in the >63 μm size fraction used. Finally, the presence of sequences of A. confertitesta and fossil specimens in the deep layers of the study cores suggests that this species, considered until now as recently invasive on the European coast, could have been present in the Atlantic coast several thousand years ago, much before any anthropogenic activity involving international shipping and commercial trades.

Li Ji, Huayong Zhang, Huayong Zhang et al.

Warming is a key factor influencing the function of the structure and function of phytoplankton communities. However, the impacts of temperature on phytoplankton resource use efficiency (RUE) in mountain rivers remain poorly understood. Here, the spatiotemporal patterns of phytoplankton community structure (biomass, community composition, and diversity), function (RUE), and the main environmental factors in a high-latitude mountainous stream were investigated to assess how temperature affects the phytoplankton RUE. The results showed that phytoplankton species richness, biomass, and RUE all increased with rising temperature, with species richness significantly higher. There was a shift in the phytoplankton community from dominated by Cyanophyta at lower temperatures to dominated by Cryptophyta at higher temperatures. Phytoplankton RUE was significantly positively correlated to species richness, but no significant relationship was observed between RUE and Pielou’s evenness. Furthermore, redundancy analysis and Mantel tests revealed that water temperature, nutrient (TP, and NH4+-N) and physicochemical variable (flow velocity, and dissolved oxygen) explained 40.40% of the overall variation in phytoplankton RUE. Phytoplankton RUE exhibited stronger responses to environmental variables than phytoplankton biomass or diversity. The results highlighted that temperature directly affected phytoplankton community composition and enhanced RUE by altering environmental conditions and biodiversity. Temperature plays a crucial role in shaping the structure and function of phytoplankton communities in rivers. Our results contribute to the deep understanding of the mechanisms by which temperature influences RUE providing a basis for the sustainable management and conservation of aquatic ecosystems and watersheds.

Fatema S. Mohamed, Rim Hamdy, Essam M. Abd-Elkhader

Jones Akuaku, Rita Sam

The African baobab (Adansonia digitata L.) is a priority Pan-African tree species. Insect pests that are associated with and damage domesticated baobab are largely unknown in the production areas of baobab. To identify and document insect pests associated with domesticated African baobab for the first time, mature and young domesticated baobab plants were, respectively, surveyed on the research fields and nursery of the Ho Technical University in Ho, Ghana. The survey targeted all insects found on baobab with the goal of documenting pests that infest baobab plants. Collected insect samples were photographed and searched using Google Lens and the iNaturalist insect identification application for their identification and taxonomic classification. The entomological specimens collected were classified into 7 orders, 11 families, and 16 insect species. The most frequent orders were Hemiptera (37.5%) and Coleoptera (31.25%). The incidence of the remaining orders (Orthoptera, Lepidoptera, Hymenoptera, Araneae, and Dictyoptera) was very low with 6.25% abundance each. Regarding absolute counts, the Coleopteran order had a significantly (p≤0.05) higher number of insects (51.48 ± 7.42955) than the other orders; Araneae (4.70 ± 7.42955), Hemiptera (1.10 ± 7.42955), Dictyoptera (0.45 ± 7.42955), Orthoptera (0.40 ± 7.42955), Hymenoptera (0.30 ± 7.42955), and Lepidoptera (0.05 ± 7.42955). No significant difference was observed among these remaining orders. The cocoa weevil (Araecerus fasciculatus) was the most dominant insect pest. Some beneficial insects were also found on the baobab plants. Monitoring and management interventions, particularly integrated pest management (IPM), that target the identified insect pests can be implemented to ensure the sustainable cultivation of baobab. Further research is required to identify and classify insect pests that may not have been captured and identified in this study.

Cassandra Upton, Gerhard Prinsloo, Paul Anton Steenkamp et al.

IntroductionSea cucumbers are ecologically and economically significant marine invertebrates, yet the metabolic diversity and bioactive potential of noncommercialized, endemic species remains poorly understood.MethodsThis study presents the first intra-species metabolomic analysis of Pseudocnella sykion, a species endemic to the Eastern coast of Southern Africa, using untargeted 1HNMR metabolomics and full-scan UPLC-QTOF-HR-MS.ResultsThe analysis revealed a diverse array of metabolites associated with protein synthesis, tissue growth, osmoregulation, and energy utilization, with distinct tissue-specific patterns across the body wall, gonad, and gut/mesentery. The gut/mesentery tissue showed higher levels of amino acids and energy-related compounds. UPLCQTOF-HR-MS tentatively identified several metabolites, including triterpene glycosides and rosmarinic acid, a phenolic compound typically associated with plants. Online resources, including the Dictionary of Marine Natural Products, contained no previously recorded compounds for P. sykion.DiscussionThese findings underscore the untapped potential of P. sykion as a source of novel metabolites and demonstrate the utility of untargeted metabolomics in generating baseline profiles for underexplored marine species. The results offer a foundation for future research into bioactivity, environmental monitoring, and cultivation strategies. While this study provides critical baseline data, challenges in metabolite identification and extraction underscore the need for further targeted analyses. Overall, this research enhances our understanding of the metabolic dynamics of sea cucumbers and advocates for continued exploration of lesser-known species to support conservation, bioprospecting, and sustainable aquaculture. It represents a pioneering effort in metabolomic profiling of Southern African sea cucumber species and lays the groundwork for future investigations into their metabolic pathways and potential bioactivities.

Jennifer E. Helm, Elizabeth G. Simpson, Lorelle I. Berkeley et al.

Abstract Understanding how vegetation management affects animals' habitat selection patterns is critical for comprehensive conservation planning. As part of a decade‐long study (2011–2019) of 486 adult female sage‐grouse in central Montana, we investigated how a conservation‐based grazing program (CGP) affected greater sage‐grouse (Centrocercus urophasianus) habitat selection at two temporal scales: (a) the seasonal scale (four biologically relevant seasons) and (b) the annual scale. We used resource selection functions to assess sage‐grouse selection for pastures enrolled in a CGP as well as plant functional type and topography. We found that sage‐grouse strongly selected shrub cover, flatter slopes, and less tree cover. They selected CGP‐enrolled pastures (Pre‐, During‐, and Post‐grazing system implementation) over Non‐CGP pastures during all seasons except the summer–fall. During the summer–fall, they selected pastures where CGP implementation was complete. Future research is needed to determine whether selection for CGP‐enrolled pastures was due to unmeasured, underlying differences between CGP and non‐CGP pastures or CGP enrollment patterns rather than effects of different grazing systems, as well as whether these habitat selection differences are linked to demographic rates or population dynamics.

Mikhail G. Katz

Infinitesimals have seen ups and downs in their tumultuous history. In the 18th century, d'Alembert set the tone by describing infinitesimals as chimeras. Some adversaries of infinitesimals, including Moigno and Connes, picked up on the term. We highlight the work of Cauchy, Noël, Poisson and Riemann. We also chronicle reactions by Moigno, Lamarle and Cantor, and signal the start of a revival with Peano.

Kiwhan Song, Boyuan Chen, Max Simchowitz et al.

Classifier-free guidance (CFG) is a key technique for improving conditional generation in diffusion models, enabling more accurate control while enhancing sample quality. It is natural to extend this technique to video diffusion, which generates video conditioned on a variable number of context frames, collectively referred to as history. However, we find two key challenges to guiding with variable-length history: architectures that only support fixed-size conditioning, and the empirical observation that CFG-style history dropout performs poorly. To address this, we propose the Diffusion Forcing Transformer (DFoT), a video diffusion architecture and theoretically grounded training objective that jointly enable conditioning on a flexible number of history frames. We then introduce History Guidance, a family of guidance methods uniquely enabled by DFoT. We show that its simplest form, vanilla history guidance, already significantly improves video generation quality and temporal consistency. A more advanced method, history guidance across time and frequency further enhances motion dynamics, enables compositional generalization to out-of-distribution history, and can stably roll out extremely long videos. Project website: https://boyuan.space/history-guidance

C. Hastie, D. Lowe, A. McAuley et al.

Previous studies on the natural history of long-COVID have been few and selective. Without comparison groups, disease progression cannot be differentiated from symptoms originating from other causes. The Long-COVID in Scotland Study (Long-CISS) is a Scotland-wide, general population cohort of adults who had laboratory-confirmed SARS-CoV-2 infection matched to PCR-negative adults. Serial, self-completed, online questionnaires collected information on pre-existing health conditions and current health six, 12 and 18 months after index test. Of those with previous symptomatic infection, 35% reported persistent incomplete/no recovery, 12% improvement and 12% deterioration. At six and 12 months, one or more symptom was reported by 71.5% and 70.7% respectively of those previously infected, compared with 53.5% and 56.5% of those never infected. Altered taste, smell and confusion improved over time compared to the never infected group and adjusted for confounders. Conversely, late onset dry and productive cough, and hearing problems were more likely following SARS-CoV-2 infection.

K. Rothnie, H. Müllerová, L. Smeeth et al.

Rationale: Acute exacerbations of chronic obstructive pulmonary disease (AECOPDs) are important adverse events in the natural history of chronic obstructive pulmonary disease (COPD). Objectives: To investigate the natural history of AECOPDs over 10 years of follow‐up. Methods: We identified 99,574 patients with COPD from January 1, 2004, to March 31, 2015, from the UK Clinical Practice Research Datalink. We defined moderate AECOPDs as those managed outside hospital and severe as those requiring hospitalization. During the baseline period (first year of follow‐up), patients were grouped according to the number and severity of AECOPDs and then followed for a maximum of 10 years (mean, 4.9 yr). We investigated the effect of baseline AECOPD number and severity on risk of further events and death. Measurements and Main Results: Around one‐quarter of the patients with COPD did not exacerbate during follow‐up. Compared with no AECOPDs in the baseline period, AECOPD number predicted the future long‐term rate of AECOPDs in a graduated fashion, ranging from hazard ratio (HR) of 1.71 (1.66‐1.77) for one event to HR of 3.41 (3.27‐3.56) for five or more events. Two or more moderate AECOPDs were also associated with an increased risk of death in a graduated fashion, ranging from HR of 1.10 (1.03‐1.18) for two moderate AECOPDs to HR of 1.57 (1.45‐1.70) for five or more moderate AECOPDs, compared with those with no AECOPDs at baseline. Severe AECOPDs were associated with an even higher risk of death (HR, 1.79; 1.65‐1.94). Conclusions: A large proportion of patients with COPD do not exacerbate over a maximum 10 years of follow‐up. AECOPD frequency in a single year predicts long‐term AECOPD rate. Increasing frequency and severity of AECOPDs is associated with risk of death and highlights the importance of preventing AECOPDs.

Ciro Gargiulo Isacco, Mario G. Balzanelli, Stefania Garzone et al.

<i>Chlamydia trachomatis</i> and human papillomavirus (HPV) are the most common pathogens found in sexually transmitted infections (STIs), and both are known to increase the risk of cervical cancer (CC) and infertility. HPV is extremely common worldwide, and scientists use it to distinguish between low-risk and high-risk genotypes. In addition, HPV transmission can occur via simple contact in the genital area. From 50 to 80% of sexually active individuals become infected with both <i>C. trachomatis</i> and HPV viruses during their lifetime, and up to 50% become infected with an HPV oncogenic genotype. The natural history of this coinfection is strongly conditioned by the balance between the host microbiome and immune condition and the infecting agent. Though the infection often regresses, it tends to persist throughout adult life asymptomatically and silently. The partnership between HPV and <i>C. trachomatis</i> is basically due to their similarities: common transmission routes, reciprocal advantages, and the same risk factors. <i>C. trachomatis</i> is a Gram-negative bacteria, similar to HPV, and an intracellular bacterium, which shows a unique biphasic development that helps the latter continue its steady progression into the host throughout the entire life. Indeed, depending on the individual’s immune condition, the <i>C. trachomatis</i> infection tends to migrate toward the upper genital tract and spread to the uterus, and the fallopian tubes open up a pathway to HPV invasion. In addition, most HPV and <i>C. trachomatis</i> infections related to the female genital tract are facilitated by the decay of the first line of defense in the vaginal environment, which is constituted by a healthy vaginal microbiome that is characterized by a net equilibrium of all its components. Thus, the aim of this paper was to highlight the complexity and fragility of the vaginal microenvironment and accentuate the fundamental role of all elements and systems involved, including the <i>Lactobacillus</i> strains (<i>Lactobacillus gasseri, Lactobacillus jensenii, Lactobacillus crispatus</i>) and the immune–endocrine system, in preserving it from oncogenic mutation. Therefore, age, diet, and genetic predisposition together with an unspecific, persistent low-grade inflammatory state were found to be implicated in a high frequency and severity grade of disease, potentially resulting in pre-cancerous and cancerous cervical lesions.

Graeme S. Cumming, Zoe G. Davies, Joern Fischer et al.

Abstract This editorial reflects on the history of the conservation movement, the strong continuing influence of its colonial past, and the counter‐emergence of a more pluralistic and respectful worldview. Conservation Letters seeks to support and foster an ethical and inclusive discipline of conservation that discards elements of its colonial and racist history. This will involve broadening the disciplinary scope of “conservation” and paying greater attention to traditional ecological knowledge and nonwestern conservation approaches. We also see a particular need for theoretical advances that guide conservation practice by informing and connecting different kinds of expertise to understand social‐ecological interactions and their implications for both people and ecosystems. Conservation can and should play a vital role in securing the joint future of ecosystems and people, but it will only achieve its full potential if it retains its social license and stays relevant to emerging concerns and values.

Emiline Smith, Chloe Heys

Jiaoling Qin, Jiaoling Qin, Sunzhe Li et al.

Accurately monitoring and predicting the large-scale dynamic changes of water levels in coastal zones is essential for its protection, restoration and sustainable development. However, there has been a challenge for achieving this goal using a single radar altimeter and retracking technique due to the diversity and complexity of coastal waveforms. To solve this issue, we proposed an approach of estimating water level of the coastal zone in Beibu Gulf, China, by combination of waveform classifications and multiple sub-waveform retrackers. This paper stacked Random Forest (RF), XGBoost and CatBoost algorithms for building an ensemble learning (SEL) model to classify coastal waveforms, and further evaluated the performance of three retracking strategies in refining waveforms using Cryosat-2, SARAL, Sentinel-3 altimeters. We compared the estimation accuracy of the coastal water levels between the single altimeter and synergistic multi-altimeter, and combined Breaks for Additive Season and Trend (BFAST), Mann-Kendall mutation test (MK) with Long Short-Term Memory (LSTM) algorithms to track the historical change process of coastal water levels, and predict its future development trend. This paper found that: (1) The SEL algorithm achieved high-precision classification of different coastal waveforms with an average accuracy of 0.959, which outperformed three single machine learning algorithms. (2) Combination of Threshold Retracker and ALES+ Retracker (TR_ALES+) achieved the better retracking quality with an improvement of correlation coefficient (R, 0.089~0.475) and root mean square error (RMSE, 0.008∼ 0.029 m) when comparing to the Threshold Retracker &amp; Primary Peak COG Retracker and Threshold Retracker &amp; Primary Peak Threshold Retracker. (3) The coastal water levels of Cryosat-2, SARAL, Sentinel-3 and multi-altimeter were in good agreement (R&gt;0.66, RMSE&lt;0.135m) with Copernicus Climate Change Service (C3S) water level. (4) The coastal water levels of the Beibu Gulf displayed a slowly rising trend from 2011 to 2021 with an average annual growth rate of 8mm/a, its lowest water level focused on May-August, the peak of water level was in October-November, and the average annual growth rate of water level from 2022-2031 was about 0.6mm/a. These results can provide guidance for scientific monitoring and sustainable management of coastal zones.

Leonid I. Gurvits

Space Very Long Baseline Interferometry is a radio astronomy technique distinguished by a record-high angular resolution reaching single-digit microseconds of arc. The paper provides a brief account of the history of developments of this technique over the period 1960s-2020s.

Jessica López Espejel, Mahaman Sanoussi Yahaya Alassan, El Mehdi Chouham et al.

Java Code Generation consists in generating automatically Java code from a Natural Language Text. This NLP task helps in increasing programmers' productivity by providing them with immediate solutions to the simplest and most repetitive tasks. Code generation is a challenging task because of the hard syntactic rules and the necessity of a deep understanding of the semantic aspect of the programming language. Many works tried to tackle this task using either RNN-based, or Transformer-based models. The latter achieved remarkable advancement in the domain and they can be divided into three groups: (1) encoder-only models, (2) decoder-only models, and (3) encoder-decoder models. In this paper, we provide a comprehensive review of the evolution and progress of deep learning models in Java code generation task. We focus on the most important methods and present their merits and limitations, as well as the objective functions used by the community. In addition, we provide a detailed description of datasets and evaluation metrics used in the literature. Finally, we discuss results of different models on CONCODE dataset, then propose some future directions.

E. Burn, C. Tebé, S. Fernández-Bertolín et al.

The natural history of coronavirus disease 2019 (COVID-19) has yet to be fully described. Here, we use patient-level data from the Information System for Research in Primary Care (SIDIAP) to summarise COVID-19 outcomes in Catalonia, Spain. We included 5,586,521 individuals from the general population. Of these, 102,002 had an outpatient diagnosis of COVID-19, 16,901 were hospitalised with COVID-19, and 5273 died after either being diagnosed or hospitalised with COVID-19 between 1st March and 6th May 2020. Older age, being male, and having comorbidities were all generally associated with worse outcomes. These findings demonstrate the continued need to protect those at high risk of poor outcomes, particularly older people, from COVID-19 and provide appropriate care for those who develop symptomatic disease. While risks of hospitalisation and death were lower for younger populations, there is a need to limit their role in community transmission. Establishing the natural history of COVID-19 requires longitudinal data from population-based cohorts. Here, the authors use linked primary care, testing, and hospital data to describe the disease in ~100,000 individuals with a COVID-19 diagnosis among a population of ~5.5 million in Catalonia, Spain.

Jinhye Kim, G. Hiura, E. Oelsner et al.

Objective To determine the prevalence, risk factors and natural history of hiatal hernia (HH) on CT in the general population. Materials and methods The Multi-Ethnic Study of Atherosclerosis (MESA) acquired full-lung CT on 3200 subjects, aged 53–94 years. Three blinded observers independently determined presence/absence and type (I–IV) of HH. Associations between HH and participant characteristics were assessed via unadjusted and multivariable-adjusted relative risk regression. HH natural history was assessed compared with prior MESA CT. Results Excellent interobserver agreement was found for presence (κ=0.86) and type of HH (κ=0.97). Among 316 HH identified (prevalence=9.9%), 223 (71%) were type I and 93 (29%) were type III. HH prevalence increased with age, from 2.4% in 6th decade to 16.6% in 9th decade (unadjusted prevalence ratio (PR)=1.1 (95% CI 1.04 to 1.1)). HH prevalence was greater in women (12.7%) than men (7.0%) (unadjusted PR=1.8 (95% CI 1.5 to 2.3)) and associated with proton pump inhibitor use (p<0.001). In 75 participants with HH with 10-year follow-up, median HH area increased from 9.9 cm2 to 17.9 cm2 (p=0.02) with a higher mean body mass index (BMI) in subjects with increasing HH size compared with HH decreasing in size: mean BMI=30.2±6.2 vs 26.8±7.2 (p=0.02). Conclusion HH on non-contrast CT is prevalent in the general population, increasing with age, female gender and BMI. Its association with proton pump inhibitor use confirms a role in gastro-oesophageal reflux disease and HH progression is associated with increased BMI. Trial registration number NCT00005487.