Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
1.
Ecol Appl ; 34(2): e2934, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38071693

RESUMEN

Species distribution models are vital to management decisions that require understanding habitat use patterns, particularly for species of conservation concern. However, the production of distribution maps for individual species is often hampered by data scarcity, and existing species maps are rarely spatially validated due to limited occurrence data. Furthermore, community-level maps based on stacked species distribution models lack important community assemblage information (e.g., competitive exclusion) relevant to conservation. Thus, multispecies, guild, or community models are often used in conservation practice instead. To address these limitations, we aimed to generate fine-scale, spatially continuous, nationwide maps for species represented in the North American Breeding Bird Survey (BBS) between 1992 and 2019. We developed ensemble models for each species at three spatial resolutions-0.5, 2.5, and 5 km-across the conterminous United States. We also compared species richness patterns from stacked single-species models with those of 19 functional guilds developed using the same data to assess the similarity between predictions. We successfully modeled 192 bird species at 5-km resolution, 160 species at 2.5-km resolution, and 80 species at 0.5-km resolution. However, the species we could model represent only 28%-56% of species found in the conterminous US BBSs across resolutions owing to data limitations. We found that stacked maps and guild maps generally had high correlations across resolutions (median = 84%), but spatial agreement varied regionally by resolution and was most pronounced between the East and West at the 5-km resolution. The spatial differences between our stacked maps and guild maps illustrate the importance of spatial validation in conservation planning. Overall, our species maps are useful for single-species conservation and can support fine-scale decision-making across the United States and support community-level conservation when used in tandem with guild maps. However, there remain data scarcity issues for many species of conservation concern when using the BBS for single-species models.


Asunto(s)
Aves , Ecosistema , Animales , Estados Unidos
2.
Ecol Appl ; 32(6): e2624, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35404493

RESUMEN

Human activities alter ecosystems everywhere, causing rapid biodiversity loss and biotic homogenization. These losses necessitate coordinated conservation actions guided by biodiversity and species distribution spatial data that cover large areas yet have fine-enough resolution to be management-relevant (i.e., ≤5 km). However, most biodiversity products are too coarse for management or are only available for small areas. Furthermore, many maps generated for biodiversity assessment and conservation do not explicitly quantify the inherent tradeoff between resolution and accuracy when predicting biodiversity patterns. Our goals were to generate predictive models of overall breeding bird species richness and species richness of different guilds based on nine functional or life-history-based traits across the conterminous United States at three resolutions (0.5, 2.5, and 5 km) and quantify the tradeoff between resolution and accuracy and, hence, relevance for management of the resulting biodiversity maps. We summarized 18 years of North American Breeding Bird Survey data (1992-2019) and modeled species richness using random forests, including 66 predictor variables (describing climate, vegetation, geomorphology, and anthropogenic conditions), 20 of which we newly derived. Among the three spatial resolutions, the percentage variance explained ranged from 27% to 60% (median = 54%; mean = 57%) for overall species richness and 12% to 87% (median = 61%; mean = 58%) for our different guilds. Overall species richness and guild-specific species richness were best explained at 5-km resolution using ~24 predictor variables based on percentage variance explained, symmetric mean absolute percentage error, and root mean square error values. However, our 2.5-km-resolution maps were almost as accurate and provided more spatially detailed information, which is why we recommend them for most management applications. Our results represent the first consistent, occurrence-based, and nationwide maps of breeding bird richness with a thorough accuracy assessment that are also spatially detailed enough to inform local management decisions. More broadly, our findings highlight the importance of explicitly considering tradeoffs between resolution and accuracy to create management-relevant biodiversity products for large areas.


Asunto(s)
Aves , Ecosistema , Animales , Biodiversidad , Actividades Humanas , Humanos , Estados Unidos
3.
iScience ; 24(8): 102840, 2021 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-34368656

RESUMEN

Maintaining connectivity between high-elevation public lands is important for wolverines and other species of conservation concern. This work represents the first effort to prioritize wolverine connectivity under future climate conditions using a systematic conservation planning framework. We optimized 10, 15, 20, and 50% of habitat features for wolverines using integer linear programming. We identified 369 privately owned areas in the 10% solution, 572 in the 15% solution, 822 in the 20% solution, and 3,996 in the 50% solution where voluntary landowner easements would improve the long-term landscape functionality for wolverine connectivity. The median estimated easements ranged from $8,762 to $12,220 across the four solutions (total costs $14,874,371 to $196,346,714). Overall, this effort demonstrates the utility of optimization problems for conserving connectivity, provides a proactive tool to engage potential collaborators, identifies easements that will likely protect various subalpine species, and offers a framework for the conservation of additional species.

4.
Pediatr Dermatol ; 27(2): 166-9, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20537068

RESUMEN

Individuals infected with the human immunodeficiency virus (HIV) are at increased risk for human papillomavirus (HPV)-related cancers of the anogenital region. A majority of these cancers have been reported in adult patients; few reports are available regarding anogenital HPV-associated carcinomas developing in children. We report a case of perianal Bowen disease in an HIV-positive child. An 8-year-old HIV-positive boy with a history of perianal verrucous lesions presented to a clinic in Lesotho because his caregiver noted his lesions were changing in color, texture, and extent. Histologic sections revealed squamous cell carcinoma in situ. Several cases of anogenital condyloma in HIV-positive children have been reported, but very few cases of HPV-associated cancer. Children with vertically transmitted HIV may be uniquely susceptible to persistent infection with strains of HPV acquired perinatally. While the introduction of highly active antiretroviral therapy has resulted in immune restoration, decreased opportunistic infection, and increased life expectancy for children and adults with HIV, it has not affected the incidence of HPV-related cancers in these patients. The increased life expectancy of children with HIV may actually put them at risk for developing an HPV-related anogenital cancer.


Asunto(s)
Neoplasias del Ano/virología , Enfermedad de Bowen/virología , Carcinoma in Situ/virología , Carcinoma de Células Escamosas/virología , Infecciones por VIH/complicaciones , Infecciones por Papillomavirus/etiología , Neoplasias Cutáneas/virología , Neoplasias del Ano/patología , Enfermedad de Bowen/patología , Carcinoma in Situ/patología , Carcinoma de Células Escamosas/patología , Niño , Humanos , Masculino , Neoplasias Cutáneas/patología
5.
Psychosomatics ; 50(3): 293-6, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19567772

RESUMEN

BACKGROUND: Genital herpes is a common and painful infection. Its prevalence within the United States is estimated to be 40 million to 60 million people. Three medications, acyclovir, valacyclovir, and famciclovir, have been shown to reduce the duration and severity of the disease. OBJECTIVE: The authors report on the first known case of valacyclovir-induced psychosis with symptoms of mania in a young woman with no previous psychiatric history. METHOD: The patient presented with irritable mood and grandiose delusions 72 hours after starting valacyclovir for genital herpes. Valacyclovir treatment was stopped, and risperidone was initiated. RESULTS: The symptoms continued after stopping the valacyclovir, but improved with risperidone. DISCUSSION: There are reports of neuropsychiatric side effects with valacyclovir's structural analogs in elderly patients with renal dysfunction. Clinicians should be aware that valacyclovir may induce psychosis with manic presentation in young, healthy patients without a psychiatric history.


Asunto(s)
Aciclovir/análogos & derivados , Antivirales/efectos adversos , Trastorno Bipolar/inducido químicamente , Herpes Genital/tratamiento farmacológico , Psicosis Inducidas por Sustancias/diagnóstico , Valina/análogos & derivados , Aciclovir/efectos adversos , Aciclovir/uso terapéutico , Adolescente , Antipsicóticos/uso terapéutico , Antivirales/uso terapéutico , Trastorno Bipolar/diagnóstico , Trastorno Bipolar/tratamiento farmacológico , Femenino , Humanos , Psicosis Inducidas por Sustancias/tratamiento farmacológico , Recurrencia , Risperidona/uso terapéutico , Valaciclovir , Valina/efectos adversos , Valina/uso terapéutico
6.
Org Lett ; 6(14): 2317-20, 2004 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-15228268

RESUMEN

[reaction: see text] Three asymmetric pathways to the kavalactones have been developed. The first method is chiral auxiliary-based and utilizes aldol reactions of N-acetyl thiazolidinethiones followed by a malonate displacement/decarboxylation reaction. The second approach uses the asymmetric catalytic Mukaiyama additions of dienolate nucleophile equivalents developed by Carreira and Sato. Finally, tin-substituted intermediates, prepared by either of these routes, can serve as advanced general precursors of kavalactone derivatives via Pd(0)-catalyzed Stille couplings with aryl halides.


Asunto(s)
Lactonas/síntesis química , Pironas/síntesis química , Catálisis , Indicadores y Reactivos , Compuestos Organometálicos/química , Paladio/química , Estereoisomerismo , Estaño/química
7.
J Org Chem ; 73(1): 142-50, 2008 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-18052386

RESUMEN

An enantioselective, convergent total synthesis of the antiviral marine natural product (-)-hennoxazole A is completed in 14 steps (longest linear sequence) from commercially available 4-methyloxazole-2-carboxylic acid. Synthesis of the C(1)-C(15) pyran/bisoxazole fragment takes advantage of an aldol-like coupling between a dimethyl acetal and an N-acetylthiazolidinethione for the direct, stereoselective installation of the C(8)-methoxy-bearing stereocenter. A one-pot acetoacetate acylation/decarboxylation/cyclodehydration of another elaborate thiazolidinethione allows for rapid assembly of the pyran-based ring system. Synthesis of the C(15)-C(25) skipped triene side chain fragment makes use of a [2,3]-Wittig-Still rearrangement for efficient installation of the trisubstituted Z-double bond. Key late-stage coupling of the two fragments is effected by deprotonation of the methyl group on the bisoxazole system using lithium diethylamide, followed by alkylation with an allylic bromide side chain segment to form the C(15)-C(16) bond.


Asunto(s)
Antivirales/síntesis química , Oxazoles/síntesis química , Antivirales/química , Conformación Molecular , Oxazoles/química , Estereoisomerismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA