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1.
BMC Psychiatry ; 24(1): 271, 2024 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-38609962

RESUMEN

BACKGROUND: Psychiatric patients are susceptible to adverse mental health impacts during COVID-19, but complex interplays between psychopathology and pandemic-related variables remain elusive. This study aimed to investigate concomitant associations between psychopathological symptoms, psychological measures and COVID-19 related variables in Chinese psychiatric patients during the peak of fifth pandemic wave in Hong Kong. METHODS: We employed network analysis to investigate inter-relationships among psychopathological symptoms (including depression, anxiety, post-traumatic stress disorder-like [PTSD-like] symptoms, insomnia, psychotic symptoms), cognitive complaints, health-related quality of life, loneliness, resilience and selected pandemic-related factors in 415 psychiatric outpatients between 28 March and 8 April, 2022. Network comparisons between genders, diagnosis (common mental disorders [CMD] vs. severe mental disorders [SMD]), and history of contracting COVID-19 at fifth wave were performed as exploratory analyses. RESULTS: Our results showed that anxiety represented the most central node in the network, as indicated by its highest node strength and expected influence, followed by depression and quality of life. Three comparatively strong connections between COVID-19 and psychopathological variables were observed including: fear of contagion and PTSD-like symptoms, COVID-19 stressor burden and PTSD-like symptoms, and COVID-19 stressor burden and insomnia. Network comparison tests revealed significant network structural difference between participants with history of contracting COVID-19 and those without, but showed no significant difference between genders as well as between CMD and SMD patients. CONCLUSIONS: Our findings suggest the pivotal role of anxiety in psychopathology network of psychiatric patients amidst COVID-19. Pandemic-related variables are critically associated with trauma/stress and insomnia symptoms. Future research is required to elucidate potential network structural changes between pandemic and post-COVID periods.


Asunto(s)
COVID-19 , Trastornos del Inicio y del Mantenimiento del Sueño , Trastornos por Estrés Postraumático , Humanos , Femenino , Masculino , Calidad de Vida , Hong Kong/epidemiología , Trastornos del Inicio y del Mantenimiento del Sueño/epidemiología , Pacientes Ambulatorios , Trastornos por Estrés Postraumático/epidemiología
2.
BMC Psychiatry ; 24(1): 372, 2024 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-38760703

RESUMEN

BACKGROUND: Psychiatric patients are susceptible to adverse mental health outcome during COVID-19 pandemic, but its associated factors are understudied. This observational cross-sectional study aimed to comprehensively examine prevalence and correlates of psychological distress, in terms of depression, anxiety and post-traumatic-stress-disorder (PTSD)-like symptoms, among Chinese adult psychiatric outpatients amidst the peak of fifth COVID-19 wave in Hong-Kong. METHODS: A total of 415 patients (comprising 246 patients with common-mental-disorders [CMD] and 169 with severe-mental-disorders [SMD]) and 399 demographically-matched controls without mental disorders were assessed with self-rated questionnaires between 28-March and 8-April-2022, encompassing illness profile, mental health symptoms, psychosocial measures (loneliness, resilience, coping styles) and COVID-19 related factors. Univariate and multivariable logistic regression analyses were conducted to determine variables associated with moderate-to-severe depressive, anxiety and PTSD-like symptoms among psychiatric patients. RESULTS: Our results showed that CMD patients had the greatest psychological distress relative to SMD patients and controls. Approximately 40-55% CMD patients and 25% SMD patients exhibited moderate-to-severe depression, anxiety and PTSD-like symptoms. Multivariable regression analyses revealed that female gender, lower educational attainment, single marital status, being housewife, more severe insomnia, psychotic-like symptoms and cognitive complaints, self-harm behavior, lower resilience, avoidance coping, never contracting COVID-19 infection, greater fear of contagion, and longer exposure to pandemic-related information were independently associated with depression, anxiety and/or PTSD-like symptoms in psychiatric patients. CONCLUSIONS: Our results affirm increased vulnerability of psychiatric patients toward psychological distress during pandemic. An array of identified correlates facilitates early detection of high-risk psychiatric patients for targeted strategies to minimize pandemic-related negative psychological impact.


Asunto(s)
Ansiedad , COVID-19 , Depresión , Trastornos por Estrés Postraumático , Humanos , COVID-19/psicología , COVID-19/epidemiología , Femenino , Masculino , Estudios Transversales , Hong Kong/epidemiología , Adulto , Prevalencia , Persona de Mediana Edad , Depresión/epidemiología , Depresión/psicología , Ansiedad/psicología , Ansiedad/epidemiología , Trastornos por Estrés Postraumático/epidemiología , Trastornos por Estrés Postraumático/psicología , Trastornos Mentales/epidemiología , Trastornos Mentales/psicología , Adaptación Psicológica , SARS-CoV-2 , Resiliencia Psicológica , Distrés Psicológico , Pueblos del Este de Asia
3.
J Exp Biol ; 226(11)2023 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-37249067

RESUMEN

Regional heterothermy is a pattern whereby different body regions are maintained at different temperatures, often to prioritize the function of certain body parts over others, or to maximize the function of organs and tissues that vary in thermal sensitivity. Regional heterothermy is relatively well understood in endotherms, where physiological mechanisms maintain heterogeneity. However, less is known about regional heterothermy in ectotherms, where behavioral mechanisms are more important for generating thermal variation. In particular, whether small and elongate ectotherms with high surface area to volume ratios such as diminutive snakes can maintain regional heterothermy, despite rapid thermal equilibration, is not yet known. We measured regional variation in body temperature and tested whether environmental heterogeneity is used to generate regional heterothermy in the ring-necked snake (Diadophis punctatus) using both field and laboratory studies. We found that ring-necked snakes have robust regional heterothermy in a variety of contexts, despite their small body size and elongate body shape. Temperature variation along the length of their bodies was not detectable when measured externally. However, snakes had higher mouth than cloacal temperatures both in the field and in laboratory thermal gradients. Further, this regional heterothermy was maintained even in ambient laboratory conditions, where the thermal environment was relatively homogeneous. Our results indicate that regional heterothermy in ring-necked snakes is not solely driven by environmental variation but is instead linked to physiological or morphological mechanisms that maintain regional variation in body temperature irrespective of environmental context.


Asunto(s)
Regulación de la Temperatura Corporal , Colubridae , Animales , Regulación de la Temperatura Corporal/fisiología , Temperatura , Tamaño Corporal
4.
Subst Use Misuse ; 58(7): 841-850, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37026397

RESUMEN

Background: Psychotropic substance use, for chemsex in particular, is common in gay or bisexual men (GBM) with HIV infection. This case-control study examined the association between Axis I psychiatric disorders and active psychotropic substance use, and identified factors affecting the prevalence of psychiatric disorders in HIV-infected GBM. Methods: Participants were 62 HIV-infected self-identified GBM who reported psychotropic substance use in the past 1 year (cases), and 55 HIV-infected self-identified GBM without psychotropic substance use in the past 1 year and had negative toxicology tests at recruitment (controls). The Chinese-bilingual Structured Clinical Interview for DSM-IV (Axis I, Patient version) was followed to establish the psychiatric diagnoses. Socio-demographic data, level of social support, HIV-related data, and pattern of psychotropic substance use were collected. Results: Cases had lower level of social support, more depressive disorders (AOR 3.4, 95% CI 1.3-8.7, p=0.01) and psychotic disorders (AOR 7.2, 95% CI 1.2-41, p=0.03) but not anxiety disorders. Significant difference in the prevalence of psychiatric disorders was only evident for disorders with onset after HIV diagnosis. Methamphetamine dependence, weekly methamphetamine use for 2 years or more, using methamphetamine beyond chemsex, duration of HIV diagnosis were significant predictors for psychiatric disorders in the cases. Conclusion: Active psychotropic substance use in HIV-infected gay or bisexual men was associated with an overall 3-fold increase in Axis I psychiatric disorders. Coordinated efforts from HIV, psychiatric and substance use services are needed to prevent harms arising from chemsex and to identify those in need and facilitate treatment access.


Asunto(s)
Trastornos Relacionados con Anfetaminas , Infecciones por VIH , Metanfetamina , Minorías Sexuales y de Género , Trastornos Relacionados con Sustancias , Masculino , Humanos , Infecciones por VIH/epidemiología , Infecciones por VIH/prevención & control , Homosexualidad Masculina/psicología , Hong Kong/epidemiología , Estudios de Casos y Controles , Conducta Sexual , Trastornos Relacionados con Sustancias/epidemiología , Trastornos Relacionados con Anfetaminas/epidemiología , Psicotrópicos
5.
BMC Genomics ; 23(1): 3, 2022 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-34983380

RESUMEN

BACKGROUND: How do xerophytic species thrive in environments that experience extreme annual drought? Although critical to the survival of many species, the genetic responses to drought stress in many non-model organisms has yet to be explored. We investigated this question in Mentzelia section Bartonia (Loasaceae), which occurs throughout western North America, including arid lands. To better understand the genetic responses to drought stress among species that occur in different habitats, the gene expression levels of three species from Mentzelia were compared across a precipitation gradient. Two de novo reference transcriptomes were generated and annotated. Leaf and root tissues were collected from control and drought shocked plants and compared to one another for differential expression. A target-gene approach was also implemented to better understand how drought-related genes from model and crop species function in non-model systems. RESULTS: When comparing the drought-shock treatment plants to their respective control plants, we identified 165 differentially expressed clusters across all three species. Differentially expressed genes including those associated with water movement, photosynthesis, and delayed senescence. The transcriptome profiling approach was coupled with a target genes approach that measured expression of 90 genes associated with drought tolerance in model organisms. Comparing differentially expressed genes with a ≥ 2 log-fold value between species and tissue types showed significant differences in drought response. In pairwise comparisons, species that occurred in drier environments differentially expressed greater genes in leaves when drought shocked than those from wetter environments, but expression in the roots mostly produced opposite results. CONCLUSIONS: Arid-adapted species mount greater genetic responses compared to the mesophytic species, which has likely evolved in response to consistent annual drought exposure across generations. Drought responses also depended on organ type. Xerophytes, for example, mounted a larger response in leaves to downregulate photosynthesis and senescence, while mobilizing carbon and regulating water in the roots. The complexity of drought responses in Mentzelia suggest that whole organism responses need to be considered when studying drought and, in particular, the physiological mechanisms in which plants regulate water, carbon, cell death, metabolism, and secondary metabolites.


Asunto(s)
Sequías , Regulación de la Expresión Génica de las Plantas , Perfilación de la Expresión Génica , Hojas de la Planta/genética , Estrés Fisiológico/genética , Transcriptoma
6.
Psychol Med ; 52(9): 1765-1776, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-33032663

RESUMEN

BACKGROUND: Depression and cardiovascular disease (CVD) are associated with each other but their relationship remains unclear. We aim to determine whether genetic predisposition to depression are causally linked to CVD [including coronary artery disease (CAD), myocardial infarction (MI), stroke and atrial fibrillation (AF)]. METHODS: Using summary statistics from the largest genome-wide association studies (GWAS) or GWAS meta-analysis of depression (primary analysis: n = 500 199), broad depression (help-seeking behavior for problems with nerves, anxiety, tension or depression; secondary analysis: n = 322 580), CAD (n = 184 305), MI (n = 171 875), stroke (n = 446 696) and AF (n = 1 030 836), genetic correlation was tested between two depression phenotypes and CVD [MI, stroke and AF (not CAD as its correlation was previously confirmed)]. Causality was inferred between correlated traits by Mendelian Randomization analyses. RESULTS: Both depression phenotypes were genetically correlated with MI (depression: rG = 0.169; p = 9.03 × 10-9; broad depression: rG = 0.123; p = 1 × 10-4) and AF (depression: rG = 0.112; p = 7.80 × 10-6; broad depression: rG = 0.126; p = 3.62 × 10-6). Genetically doubling the odds of depression was causally associated with increased risk of CAD (OR = 1.099; 95% CI 1.031-1.170; p = 0.004) and MI (OR = 1.146; 95% CI 1.070-1.228; p = 1.05 × 10-4). Adjustment for blood lipid levels/smoking status attenuated the causality between depression and CAD/MI. Null causal association was observed for CVD on depression. A similar pattern of results was observed in the secondary analysis for broad depression. CONCLUSIONS: Genetic predisposition to depression may have positive causal roles on CAD/MI. Genetic susceptibility to self-awareness of mood problems may be a strong causal risk factor of CAD/MI. Blood lipid levels and smoking may potentially mediate the causal pathway. Prevention and early diagnosis of depression are important in the management of CAD/MI.


Asunto(s)
Enfermedades Cardiovasculares , Accidente Cerebrovascular , Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/genética , Enfermedad de la Arteria Coronaria , Depresión/epidemiología , Depresión/genética , Predisposición Genética a la Enfermedad , Estudio de Asociación del Genoma Completo , Humanos , Análisis de la Aleatorización Mendeliana , Infarto del Miocardio , Polimorfismo de Nucleótido Simple , Factores de Riesgo , Accidente Cerebrovascular/epidemiología , Accidente Cerebrovascular/genética
7.
J Exp Biol ; 224(Pt 2)2021 01 22.
Artículo en Inglés | MEDLINE | ID: mdl-33328289

RESUMEN

If fitness optima for a given trait differ between males and females in a population, sexual dimorphism may evolve. Sex-biased trait variation may affect patterns of habitat use, and if the microhabitats used by each sex have dissimilar microclimates, this can drive sex-specific selection on thermal physiology. Nevertheless, tests of differences between the sexes in thermal physiology are uncommon, and studies linking these differences to microhabitat use or behavior are even rarer. We examined microhabitat use and thermal physiology in two ectothermic congeners that are ecologically similar but differ in their degree of sexual size dimorphism. Brown anoles (Anolis sagrei) exhibit male-biased sexual size dimorphism and live in thermally heterogeneous habitats, whereas slender anoles (Anolis apletophallus) are sexually monomorphic in body size and live in thermally homogeneous habitats. We hypothesized that differences in habitat use between the sexes would drive sexual divergence in thermal physiology in brown anoles, but not slender anoles, because male and female brown anoles may be exposed to divergent microclimates. We found that male and female brown anoles, but not slender anoles, used perches with different thermal characteristics and were sexually dimorphic in thermal tolerance traits. However, field-active body temperatures and behavior in a laboratory thermal arena did not differ between females and males in either species. Our results suggest that sexual dimorphism in thermal physiology can arise from phenotypic plasticity or sex-specific selection on traits that are linked to thermal tolerance, rather than from direct effects of thermal environments experienced by males and females.


Asunto(s)
Lagartos , Adaptación Fisiológica , Animales , Tamaño Corporal , Ecosistema , Femenino , Masculino , Caracteres Sexuales
8.
Biol Lett ; 16(8): 20200474, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32750271

RESUMEN

Introduced species can become invasive, damaging ecosystems and disrupting economies through explosive population growth. One mechanism underlying population expansion in invasive populations is 'enemy release', whereby the invader experiences relaxation of agonistic interactions with other species, including parasites. However, direct observational evidence of release from parasitism during invasion is rare. We mimicked the early stages of invasion by experimentally translocating populations of mite-parasitized slender anole lizards (Anolis apletophallus) to islands that varied in the number of native anoles. Two islands were anole-free prior to the introduction, whereas a third island had a resident population of Gaige's anole (Anolis gaigei). We then characterized changes in trombiculid mite parasitism over multiple generations post-introduction. We found that mites rapidly went extinct on one-species islands, but that lizards introduced to the two-species island retained mites. After three generations, the two-species island had the highest total density and biomass of lizards, but the lowest density of the introduced species, implying that the 'invasion' had been less successful. This field-transplant study suggests that native species can be 'enemy reservoirs' that facilitate co-colonization of ectoparasites with the invasive host. Broadly, these results indicate that the presence of intact and diverse native communities may help to curb invasiveness.


Asunto(s)
Lagartos , Parásitos , Animales , Ecosistema , Especies Introducidas , Islas
9.
Intern Med J ; 50 Suppl 3: 6-14, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32985093

RESUMEN

Aripiprazole, a dopamine partial agonist, is a second-generation anti-psychotic that is widely used for the treatment of schizophrenia and other psychotic disorders. A group of psychiatric experts in Hong Kong developed a set of consensus statements, aiming to facilitate the understanding of clinical properties and usages of aripiprazole among local physicians. Of note, because aripiprazole long-acting injectable has been available locally not long before the establishment of the consensus panel, which limited the discussion on its use in the local context, the consensus statements were focused primarily on oral aripiprazole. To draft the consensus statements, the panellists discussed the published evidence and their clinical experience regarding aripiprazole in a series of meetings based on several areas. At the final meeting, each drafted statement was voted on anonymously by all panellists based on its practicability of recommendation in Hong Kong. A set of consensus statements on the characteristics and clinical use of aripiprazole was established and accepted by the panel. These statements serve to provide a practical reference for physicians in Hong Kong, and possibly other parts of the Asia-Pacific region, on the use of aripiprazole in people with schizophrenia spectrum disorders and other psychotic problems.


Asunto(s)
Antipsicóticos/uso terapéutico , Aripiprazol/uso terapéutico , Esquizofrenia/tratamiento farmacológico , Consenso , Hong Kong , Humanos , Esquizofrenia/diagnóstico
10.
J Therm Biol ; 94: 102755, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33292996

RESUMEN

Organismal performance is strongly linked to temperature because of the fundamental thermal dependence of chemical reaction rates. However, the relationship between the environment and body temperature can be altered by morphology and ecology. In particular, body size and body shape can impact thermal inertia, as high surface area to volume ratios will possess low thermal mass. Habitat type can also influence thermal physiology by altering the opportunity for thermoregulation. We studied the thermal ecology and physiology of an elongate invertebrate, the bark centipede (Scolopocryptops sexspinosus). We characterized field body temperature and environmental temperature distributions, measured thermal tolerance limits, and constructed thermal performance curves for a population in southern Georgia. We found evidence that bark centipedes behaviorally thermoregulate, despite living in sheltered microhabitats, and that performance was maintained over a broad range of temperatures (over 20 °C). However, both the thermal optimum for performance and upper thermal tolerance were much higher than mean body temperature in the field. Together, these results suggest that centipedes can thermoregulate and maintain performance over a broad range of temperatures but are sensitive to extreme temperatures. More broadly, our results suggest that wide performance breadth could be an adaptation to thermal heterogeneity in space and time for a species with low thermal inertia.


Asunto(s)
Quilópodos/fisiología , Termotolerancia , Animales , Temperatura Corporal , Locomoción , Temperatura
11.
Sensors (Basel) ; 19(20)2019 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-31618911

RESUMEN

Unmanned aerial vehicles (UAVs) with high mobility can perform various roles such as delivering goods, collecting information, recording videos and more. However, there are many elements in the city that disturb the flight of the UAVs, such as various obstacles and urban canyons which can cause a multi-path effect of GPS signals, which degrades the accuracy of GPS-based localization. In order to empower the safety of the UAVs flying in urban areas, UAVs should be guided to a safe area even in a GPS-denied or network-disconnected environment. Also, UAVs must be able to avoid obstacles while landing in an urban area. For this purpose, we present the UAV detour system for operating UAV in an urban area. The UAV detour system includes a highly reliable laser guidance system to guide the UAVs to a point where they can land, and optical flow magnitude map to avoid obstacles for a safe landing.

12.
Proc Biol Sci ; 285(1878)2018 05 16.
Artículo en Inglés | MEDLINE | ID: mdl-29743257

RESUMEN

Ectothermic species are particularly sensitive to changes in temperature and may adapt to changes in thermal environments through evolutionary shifts in thermal physiology or thermoregulatory behaviour. Nevertheless, the heritability of thermal traits, which sets a limit on evolutionary potential, remains largely unexplored. In this study, we captured brown anole lizards (Anolis sagrei) from two populations that occur in contrasting thermal environments. We raised offspring from these populations in a laboratory common garden and compared the shape of their thermal performance curves to test for genetic divergence in thermal physiology. Thermal performance curves differed between populations in a common garden in ways partially consistent with divergent patterns of natural selection experienced by the source populations, implying that they had evolved in response to selection. Next, we estimated the heritability of thermal performance curves and of several traits related to thermoregulatory behaviour. We did not detect significant heritability in most components of the thermal performance curve or in several aspects of thermoregulatory behaviour, suggesting that contemporary selection is unlikely to result in rapid evolution. Our results indicate that the response to selection may be slow in the brown anole and that evolutionary change is unlikely to keep pace with current rates of environmental change.


Asunto(s)
Regulación de la Temperatura Corporal/genética , Flujo Genético , Lagartos/fisiología , Animales , Bahamas , Femenino , Lagartos/genética , Masculino , Selección Genética
13.
Am J Hematol ; 93(7): 874-881, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29659047

RESUMEN

Posttransplant lymphoproliferative disorder (PTLD) typically presents with either polymorphic or monomorphic histology. While both are the end result of immunosuppressive therapies, their origins are felt to be different with different prognoses and responsiveness to therapy, resulting in 2 different malignancies. We attempted to confirm reports suggesting that the relative frequency of these 2 histologies is shifting over time. We analyzed 3040 adult PTLD cases in the UNOS OPTN database from 1999 to 2013. Changes in PTLD cases over time were analyzed for histology, time from transplant to diagnosis, and patient EBV serostatus. We found that the relative proportion of polymorphic versus monomorphic histology has changed with an increase in the proportion of monomorphic cases with time (1999-2003, 54.9% vs. 45.1%; 2004-2008, 58.3% vs. 41.7%; 2009-2013, 69.7% vs. 30.3%; P = <.001). The change is driven by a gradual increase in the number of monomorphic PTLD with a steady number of polymorphic PTLD. The change is most strongly seen in transplant recipients who were EBV serostatus positive at the time of transplant. Potential causes are changes in immunosuppressive regimens with increased tacrolimus use (P = .009) and increased survival among transplant patients leading to later occurrence of PTLD (P = .001) that have occurred during the time frame analyzed. As organ transplantation has evolved over time, PTLD has coevolved. These changes in histology have important implications regarding the origin and clinical management of PTLD.


Asunto(s)
Trastornos Linfoproliferativos/etiología , Trasplante de Órganos/efectos adversos , Adolescente , Adulto , Infecciones por Virus de Epstein-Barr/diagnóstico , Femenino , Histología/tendencias , Historia del Siglo XX , Historia del Siglo XXI , Humanos , Trastornos Linfoproliferativos/historia , Trastornos Linfoproliferativos/virología , Masculino , Persona de Mediana Edad , Factores de Tiempo , Adulto Joven
14.
Am J Dent ; 31(Sp Is B): 3B-5B, 2018 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-31099205

RESUMEN

PURPOSE: This proceedings reviews current antibacterial and bioactive dental materials and new agents in development. METHODS: Experts from across academia, industry and clinical practice were invited to present, discuss, and work together to develop solutions to the challenge of formulating and applying antibacterial dental materials in a symposium in Seoul, Korea in June, 2016.


Asunto(s)
Antibacterianos , Restauración Dental Permanente , Antibacterianos/uso terapéutico , Materiales Dentales
15.
J Therm Biol ; 71: 232-236, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-29301695

RESUMEN

Biochemical reaction rates are highly sensitive to temperature, and the body temperatures of ectotherms covary with their immediate environment. Therefore, ectotherms should choose microhabitats that permit the maintenance of physiological function. While some previous studies have found that squamate reptiles choose retreat sites that allow them to maintain physiologically optimal body temperatures, this research has been limited in context and taxonomic scope. We sought to test these empirical patterns by studying the properties of retreat sites in the context of physiological preferences and tolerances in a population of semifossorial ring-necked snakes (Diadophis punctatus). We measured environmental temperature distributions of retreat sites, field body temperatures, thermal preferences, and both upper voluntary temperature and critical thermal minima of snakes. We found that ring-necked snakes are under larger and warmer rocks, but that body temperatures in the field do not match thermal preferences measured in the laboratory. Specifically, we found aggregated ring-necked snakes (those occurring with multiple conspecifics) select rocks providing environmental temperatures averaging 3°C higher than their preferred temperature. By contrast, solitary snakes select rocks that allowed them to maintain their body temperatures very close to their preferred temperatures. These results imply that there is substantial within and among-species variation in the role of thermal considerations in retreat-site selection. Our work also highlights the complex tradeoffs between physiological and ecological requirements that organisms must navigate in heterogeneous habitats.


Asunto(s)
Aclimatación , Temperatura Corporal , Locomoción , Serpientes/fisiología , Animales , Frío , Ecosistema , Calor
16.
IEEE Trans Med Imaging ; 43(2): 820-831, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37801381

RESUMEN

Image segmentation is essential to medical image analysis as it provides the labeled regions of interest for the subsequent diagnosis and treatment. However, fully-supervised segmentation methods require high-quality annotations produced by experts, which is laborious and expensive. In addition, when performing segmentation on another unlabeled image modality, the segmentation performance will be adversely affected due to the domain shift. Unsupervised domain adaptation (UDA) is an effective way to tackle these problems, but the performance of the existing methods is still desired to improve. Also, despite the effectiveness of recent Transformer-based methods in medical image segmentation, the adaptability of Transformers is rarely investigated. In this paper, we present a novel UDA framework using a Transformer for building a cross-modality segmentation method with the advantages of learning long-range dependencies and transferring attentive information. To fully utilize the attention learned by the Transformer in UDA, we propose Meta Attention (MA) and use it to perform a fully attention-based alignment scheme, which can learn the hierarchical consistencies of attention and transfer more discriminative information between two modalities. We have conducted extensive experiments on cross-modality segmentation using three datasets, including a whole heart segmentation dataset (MMWHS), an abdominal organ segmentation dataset, and a brain tumor segmentation dataset. The promising results show that our method can significantly improve performance compared with the state-of-the-art UDA methods.


Asunto(s)
Neoplasias Encefálicas , Humanos , Procesamiento de Imagen Asistido por Computador
17.
IEEE J Biomed Health Inform ; 28(9): 5347-5359, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38669172

RESUMEN

This paper introduces an effective and efficient framework for retinal vessel segmentation. First, we design a Transformer-CNN hybrid model in which a Transformer module is inserted inside the U-Net to capture long-range interactions. Second, we design a dual-path decoder in the U-Net framework, which contains two decoding paths for multi-task outputs. Specifically, we train the extra decoder to predict vessel skeletons as an auxiliary task which helps the model learn balanced features. The proposed framework, named as TSNet, not only achieves good performances in a fully supervised learning manner but also enables a rough skeleton annotation process. The annotators only need to roughly delineate vessel skeletons instead of giving precise pixel-wise vessel annotations. To learn with rough skeleton annotations plus a few precise vessel annotations, we propose a skeleton semi-supervised learning scheme. We adopt a mean teacher model to produce pseudo vessel annotations and conduct annotation correction for roughly labeled skeletons annotations. This learning scheme can achieve promising performance with fewer annotation efforts. We have evaluated TSNet through extensive experiments on five benchmarking datasets. Experimental results show that TSNet yields state-of-the-art performances on retinal vessel segmentation and provides an efficient training scheme in practice.


Asunto(s)
Redes Neurales de la Computación , Vasos Retinianos , Vasos Retinianos/diagnóstico por imagen , Humanos , Algoritmos , Interpretación de Imagen Asistida por Computador/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Aprendizaje Profundo
18.
Bioengineering (Basel) ; 11(1)2024 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-38275581

RESUMEN

Precise surveillance and assessment of spinal disorders are important for improving health care and patient survival rates. The assessment of spinal disorders, such as scoliosis assessment, depends heavily on precise vertebra landmark localization. However, existing methods usually search for only a handful of keypoints in a high-resolution image. In this paper, we propose the S2D-VLI VLDet network, a unified end-to-end vertebra landmark detection network for the assessment of scoliosis. The proposed network considers the spatially relevant information both from inside and between vertebrae. The new vertebral line interpolation method converts the training labels from sparse to dense, which can improve the network learning process and method performance. In addition, through the combined use of the Cartesian and polar coordinate systems in our method, the symmetric mean absolute percentage error (SMAPE) in scoliosis assessment can be reduced substantially. Specifically, as shown in the experiments, the SMAPE value decreases from 9.82 to 8.28. The experimental results indicate that our proposed approach is beneficial for estimating the Cobb angle and identifying landmarks in X-ray scans with low contrast.

19.
Med Image Anal ; 97: 103277, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39094461

RESUMEN

Model quantization is a promising technique that can simultaneously compress and accelerate a deep neural network by limiting its computation bit-width, which plays a crucial role in the fast-growing AI industry. Despite model quantization's success in producing well-performing low-bit models, the quantization process itself can still be expensive, which may involve a long fine-tuning stage on a large, well-annotated training set. To make the quantization process more efficient in terms of both time and data requirements, this paper proposes a fast and accurate post-training quantization method, namely EfficientQ. We develop this new method with a layer-wise optimization strategy and leverage the powerful alternating direction method of multipliers (ADMM) algorithm to ensure fast convergence. Furthermore, a weight regularization scheme is incorporated to provide more guidance for the optimization of the discrete weights, and a self-adaptive attention mechanism is proposed to combat the class imbalance problem. Extensive comparison and ablation experiments are conducted on two publicly available medical image segmentation datasets, i.e., LiTS and BraTS2020, and the results demonstrate the superiority of the proposed method over various existing post-training quantization methods in terms of both accuracy and optimization speed. Remarkably, with EfficientQ, the quantization of a practical 3D UNet only requires less than 5 min on a single GPU and one data sample. The source code is available at https://github.com/rongzhao-zhang/EfficientQ.


Asunto(s)
Algoritmos , Procesamiento de Imagen Asistido por Computador , Redes Neurales de la Computación , Humanos , Procesamiento de Imagen Asistido por Computador/métodos
20.
Ecol Evol Physiol ; 97(2): 81-96, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38728692

RESUMEN

AbstractTropical ectotherms are thought to be especially vulnerable to climate change because they have evolved in temporally stable thermal environments and therefore have decreased tolerance for thermal variability. Thus, they are expected to have narrow thermal tolerance ranges, live close to their upper thermal tolerance limits, and have decreased thermal acclimation capacity. Although models often predict that tropical forest ectotherms are especially vulnerable to rapid environmental shifts, these models rarely include the potential for plasticity of relevant traits. We measured phenotypic plasticity of thermal tolerance and thermal preference as well as multitissue transcriptome plasticity in response to warmer temperatures in a species that previous work has suggested is highly vulnerable to climate warming, the Panamanian slender anole lizard (Anolis apletophallus). We found that many genes, including heat shock proteins, were differentially expressed across tissues in response to short-term warming. Under long-term warming, the voluntary thermal maxima of lizards also increased, although thermal preference exhibited only limited plasticity. Using these data, we modeled changes in the activity time of slender anoles through the end of the century under climate change and found that plasticity should delay declines in activity time by at least two decades. Our results suggest that slender anoles, and possibly other tropical ectotherms, can alter the expression of genes and phenotypes when responding to shifting environmental temperatures and that plasticity should be considered when predicting the future of organisms under a changing climate.


Asunto(s)
Cambio Climático , Lagartos , Termotolerancia , Clima Tropical , Animales , Lagartos/genética , Lagartos/fisiología , Termotolerancia/genética , Bosques , Aclimatación/genética , Aclimatación/fisiología , Transcriptoma , Expresión Génica
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