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1.
Clin Radiol ; 79(5): 378-385, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38383252

RESUMO

AIM: To assess the safety and efficacy of superior hypogastric nerve block (SHNB) in managing periprocedural pain associated with uterine fibroid embolisation (UFE) and in facilitating same-day discharge. MATERIALS AND METHODS: Prospectively enrolled case-control study with retrospective analysis comprising 119 eligible patients who underwent UFE for symptomatic fibroids was undertaken at a UK teaching hospital between January 2016 and September 2022. SHNB was administered to 62 participants in addition to systemic analgesia; 57 participants received systemic analgesia alone. SHNB was performed mid-UFE using 20 ml of 0.25% levobupivacaine. Pain scores were assessed using an 11-point (0-10) verbal numerical rating scale (NRS). The study received research and ethics committee approval. Statistical analysis was performed using the chi-square and independent t-test or Mann-Whitney U-test. A p-value of <0.05 defined significance. RESULTS: Participants who received SHNB experienced significantly less pain during the first 6 h post-procedure (averaged median pain score 2.6 versus 3.8, p=0.031). SHNB reduced the proportion of participants requiring post-procedural anti-emetics (45% versus 63%, p<0.05). For participants entered on the day-case pathway (SHNB = 34, no-SHNB = 16), those who received SHNB had a higher rate of successful same-day discharge (62% versus 31%, p=0.044). This SHNB group required significantly less opioids for periprocedural pain relief (median oral morphine equivalents; 44 mg versus 80 mg, p=0.020). No SHNB-related adverse events occurred. CONCLUSION: SHNB is safe and effective in reducing perioperative pain, opioid requirements, and anti-emetic use in patients undergoing UFE for symptomatic fibroids. SHNB, as an adjunct to analgesic optimisation, facilitates same-day discharge, which is often limited by severe post-embolisation pain.


Assuntos
Leiomioma , Bloqueio Nervoso , Neoplasias Uterinas , Feminino , Humanos , Analgésicos Opioides/uso terapêutico , Neoplasias Uterinas/cirurgia , Estudos de Casos e Controles , Estudos Retrospectivos , Alta do Paciente , Resultado do Tratamento , Leiomioma/cirurgia , Bloqueio Nervoso/métodos , Dor/cirurgia , Dor Pós-Operatória/prevenção & controle , Dor Pós-Operatória/cirurgia
2.
Ann Clin Microbiol Antimicrob ; 18(1): 27, 2019 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-31551072

RESUMO

BACKGROUND: Identification of all possible HIV reservoirs is an important aspect in HIV eradication efforts. The urinary tract has however not been well studied as a potential HIV reservoir. In this pilot study we molecularly characterized HIV-1 viruses in urine and plasma samples to investigate HIV-1 replication, compartmentalization and persistence in the urinary tract. METHODS: Prospectively collected urine and blood samples collected over 12-36 months from 20 HIV-1 infected individuals were analysed including sampling points from prior to and after ART initiation. HIV-1 pol gene RNA and DNA from urine supernatant and urine pellets respectively were analysed and compared to plasma RNA viruses from the same individual. RESULTS: HIV-1 nucleic acid was detected in urine samples from at least one time point in 8/20 (40%) treatment-naïve subjects compared to 1/13 (7.7%) individuals on antiretroviral treatment (ART) during periods of plasma viral suppression and 1/7 (14.3%) individuals with virological failure. HIV-1 RNA was undetectable in urine samples after ART initiation but HIV-1 DNA was detectable in one patient more than 6 months after treatment initiation. There was co-clustering of urine-derived pol sequences but some urine-derived sequences were interspersed among the plasma-derived sequences. CONCLUSIONS: Suppressive ART reduces HIV-1 replication in the urinary tract but HIV-1 DNA may persist in these cells despite treatment. A larger number of sequences would be required to confirm HIV compartmentalization in the urinary tract.


Assuntos
Genótipo , Infecções por HIV/virologia , HIV-1/classificação , HIV-1/isolamento & purificação , Sistema Urinário/virologia , Adulto , Antirretrovirais/uso terapêutico , DNA Viral/genética , DNA Viral/isolamento & purificação , Feminino , Infecções por HIV/tratamento farmacológico , HIV-1/genética , Humanos , Masculino , Projetos Piloto , Plasma/virologia , Estudos Prospectivos , RNA Viral/genética , RNA Viral/isolamento & purificação , Análise de Sequência de DNA , Carga Viral , Produtos do Gene pol do Vírus da Imunodeficiência Humana/genética
3.
Proc Biol Sci ; 285(1887)2018 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-30232159

RESUMO

Extinction risk assessments of marine invertebrate species remain scarce, which hinders effective management of marine biodiversity in the face of anthropogenic impacts. To help close this information gap, in this paper we provide a metric of relative extinction risk that combines palaeontological data, in the form of extinction rates calculated from the fossil record, with two known correlates of risk in the modern day: geographical range size and realized thermal niche. We test the performance of this metric-Palaeontological Extinction Risk In Lineages (PERIL)-using survivorship analyses of Pliocene bivalve faunas from California and New Zealand, and then use it to identify present-day hotspots of extinction vulnerability for extant shallow-marine Bivalvia. Areas of the ocean where concentrations of bivalve species with higher PERIL scores overlap with high levels of climatic or anthropogenic stressors should be considered of most immediate concern for both conservation and management.


Assuntos
Distribuição Animal , Bivalves/classificação , Extinção Biológica , Animais , Organismos Aquáticos , Bivalves/fisiologia , California , Ecossistema , Fósseis , Nova Zelândia , Paleontologia , Temperatura
4.
Proc Biol Sci ; 283(1844)2016 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-27928038

RESUMO

The determinants of the structure, functioning and resilience of pelagic ecosystems across most of the polar regions are not well known. Improved understanding is essential for assessing the value of biodiversity and predicting the effects of change (including in biodiversity) on these ecosystems and the services they maintain. Here we focus on the trophic interactions that underpin ecosystem structure, developing comparative analyses of how polar pelagic food webs vary in relation to the environment. We highlight that there is not a singular, generic Arctic or Antarctic pelagic food web, and, although there are characteristic pathways of energy flow dominated by a small number of species, alternative routes are important for maintaining energy transfer and resilience. These more complex routes cannot, however, provide the same rate of energy flow to highest trophic-level species. Food-web structure may be similar in different regions, but the individual species that dominate mid-trophic levels vary across polar regions. The characteristics (traits) of these species are also different and these differences influence a range of food-web processes. Low functional redundancy at key trophic levels makes these ecosystems particularly sensitive to change. To develop models for projecting responses of polar ecosystems to future environmental change, we propose a conceptual framework that links the life histories of pelagic species and the structure of polar food webs.


Assuntos
Ecossistema , Cadeia Alimentar , Regiões Antárticas , Regiões Árticas , Biodiversidade , Mudança Climática , Oceanos e Mares
5.
Virol J ; 13(1): 170, 2016 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-27733203

RESUMO

BACKGROUND: Although the use of highly active antiretroviral therapy in HIV positive individuals has proved to be effective in suppressing the virus to below detection limits of commonly used assays, virological failure associated with drug resistance is still a major challenge in some settings. The prevalence and effect of pre-treatment resistance associated variants on virological outcomes may also be underestimated because of reliance on conventional population sequencing data which excludes minority species. We investigated long term virological outcomes and the prevalence and pattern of pre-treatment minority drug resistance mutations in individuals initiating HAART at a local HIV clinic. METHODS: Patient's records of viral load results and CD4 cell counts from routine treatment monitoring were used and additional pre-treatment blood samples for Sanger sequencing were obtained. A selection of pre-treatment samples from individuals who experienced virological failure were evaluated for minority resistance associated mutations to 1 % prevalence and compared to individuals who achieved viral suppression. RESULTS: At least one viral load result after 6 months or more of treatment was available for 65 out of 78 individuals followed for up to 33 months. Twenty (30.8 %) of the 65 individuals had detectable viremia and eight (12.3 %) of them had virological failure (viral load > 1000 RNA copies/ml) after at least 6 months of HAART. Viral suppression, achieved by month 8 to month 13, was followed by low level viremia in 10.8 % of patients and virological failure in one patient after month 20. There was potentially reduced activity to Emtricitabine or Tenofovir in three out of the eight cases in which minority drug resistance associated variants were investigated but detectable viremia occurred in one of these cases while the activity of Efavirenz was generally reduced in all the eight cases. CONCLUSIONS: Early viral suppression was followed by low level viremia for some patients which may be an indication of failure to sustain viral suppression over time. The low level viremia may also be representing early stages of resistance development. The mutation patterns detected in the minority variants showed potential reduced drug sensitivity which highlights their potential to dominate after treatment initiation. TRIAL REGISTRATION: Not applicable.


Assuntos
Fármacos Anti-HIV/uso terapêutico , Farmacorresistência Viral , Infecções por HIV/tratamento farmacológico , Infecções por HIV/virologia , HIV-1/efeitos dos fármacos , HIV-1/genética , Adulto , Idoso , Contagem de Linfócito CD4 , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Taxa de Mutação , Prevalência , Resultado do Tratamento , Carga Viral , Adulto Jovem
6.
Build Environ ; 92: 756-763, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32288032

RESUMO

Increasing a ceiling fan's speed from its lowest setting of 61 rpm, which resulted in 0.77 m3/s of airflow, to its highest setting of 176 rpm, which resulted in 2.5 m3/s of airflow, or having the fan blow either upward or downward had no statistically significant effect on the efficacy of upper-room ultraviolet germicidal irradiation (UVGI). This outcome suggests that air circulation due to the ceiling fan was sufficient and that any additional increase would not improve efficacy. Numerous experimental studies on upper-room UVGI in which fans were used to provide air mixing have been published. However, none have quantified the air movement produced by these fans or described their tests in sufficient detail to allow results to be compared to predictions using computational fluid dynamics (CFD). The present work provides the required information. In addition to the usual boundary conditions needed for CFD, we made experimental measurements of UV susceptibility of the microorganisms used in the upper-room UVGI tests. We measured UV susceptibilities for Mycobacterium parafortuitum and Bacillus atrophaeus spores to be 0.074 and 0.018 m2/J, respectively. In a previous publication, we reported the spatial distribution of fluence rate, which is also needed for predicting efficacy from CFD. In a companion paper referred to as Part II, upper-room UVGI efficacy was predicted by both Eulerian and Lagrangian CFD and compared to the experimental results from the present study.

7.
Indoor Air ; 24(2): 116-24, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23889191

RESUMO

A novel whole ceiling upper-room ultraviolet germicidal irradiation (UVGI) system [eggcrate ultraviolet (UV)] has been developed that incorporates open-cell 'eggcrate'-suspended ceiling panels and bare UV lamps with a ceiling fan. Upper-room UVGI is more effective for air disinfection than mechanical ventilation at much lower installation and operating costs. Conventional upper-room UVGI fixtures employ multiple tightly spaced horizontal louvers to confine UV to the upper-room. These louvered fixtures protect occupants in the lower-room from UV-induced eye and skin irritation, but at a major cost to fixture efficiency. Using a lamp and ballast from a conventional upper-room UVGI fixture in the eggcrate UV system, the germicidal efficacy was markedly improved even though the UV radiation emitted by the lamp was unchanged. This fundamental change in the application of upper-room UVGI air disinfection should permit wider, more effective application of UVGI globally to reduce the spread of airborne infection.


Assuntos
Microbiologia do Ar , Desinfecção/instrumentação , Ambiente Controlado , Raios Ultravioleta
8.
Vet Pathol ; 50(6): 1109-15, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23528942

RESUMO

The aims of this prospective study were to quantify steatosis in dogs with congenital portosystemic shunts (CPS) using a fat-specific stain, to compare the amount of steatosis in different lobes of the liver, and to evaluate intra- and interobserver variability in lipid point counting. Computer-assisted point counting of lipid droplets was undertaken following Oil Red O staining in 21 dogs with congenital portosystemic shunts and 9 control dogs. Dogs with congenital portosystemic shunts had significantly more small lipid droplets (<6 µ) than control dogs (P = .0013 and .0002, respectively). There was no significant difference in steatosis between liver lobes for either control dogs and CPS dogs. Significant differences were seen between observers for the number of large lipid droplets (>9 µ) and lipogranulomas per tissue point (P = .023 and .01, respectively). In conclusion, computer-assisted counting of lipid droplets following Oil Red O staining of liver biopsy samples allows objective measurement and detection of significant differences between dogs with CPS and normal dogs. This method will allow future evaluation of the relationship between different presentations of CPS (anatomy, age, breed) and lipidosis, as well as the impact of hepatic lipidosis on outcomes following surgical shunt attenuation.


Assuntos
Compostos Azo , Doenças do Cão/patologia , Fígado Gorduroso/veterinária , Sistema Porta/anormalidades , Coloração e Rotulagem/veterinária , Animais , Biópsia/veterinária , Cruzamento , Estudos de Casos e Controles , Diagnóstico por Computador , Doenças do Cão/congênito , Doenças do Cão/metabolismo , Doenças do Cão/cirurgia , Cães , Fígado Gorduroso/metabolismo , Fígado Gorduroso/patologia , Feminino , Fígado/metabolismo , Fígado/patologia , Testes de Função Hepática/veterinária , Masculino , Variações Dependentes do Observador , Sistema Porta/cirurgia , Estudos Prospectivos , Triglicerídeos/análise
9.
Clin Infect Dis ; 54 Suppl 4: S334-8, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22544199

RESUMO

Surveillance of human immunodeficiency virus type 1 transmitted drug resistance (TDR) was conducted among pregnant women in South Africa over a 5-year period after the initiation of a large national antiretroviral treatment program. Analysis of TDR data from 9 surveys conducted between 2005 and 2009 in 2 provinces of South Africa suggests that while TDR remains low (<5%) in Gauteng Province, it may be increasing in KwaZulu-Natal, with the most recent survey showing moderate (5%-15%) levels of resistance to the nonnucleoside reverse transcriptase inhibitor drug class.


Assuntos
Antirretrovirais/farmacologia , Infecções por HIV/epidemiologia , Infecções por HIV/transmissão , HIV-1/classificação , Adolescente , Adulto , Farmacorresistência Viral , Feminino , Técnicas de Genotipagem , Infecções por HIV/virologia , HIV-1/efeitos dos fármacos , HIV-1/genética , Humanos , Vigilância da População , Gravidez , Complicações Infecciosas na Gravidez/epidemiologia , Complicações Infecciosas na Gravidez/virologia , Estudos Retrospectivos , África do Sul/epidemiologia
10.
J Vet Intern Med ; 24(5): 1063-8, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20707838

RESUMO

BACKGROUND: Foreign body aspiration is a differential diagnosis for acute or chronic cough that requires medical or surgical management in animals. HYPOTHESIS: Success of bronchoscopy in airway foreign body removal is dependent on the size of the animal, duration of clinical signs, and location of the foreign body. ANIMALS: Thirty-two dogs and 5 cats with airway foreign bodies identified at the UC Davis Veterinary Medical Teaching Hospital. METHODS: Retrospective case study evaluating the role of duration of clinical signs and body size in successful bronchoscopic removal of foreign bodies. In addition, radiographic localization of disease was compared with bronchoscopic identification. Bronchoalveolar lavage (BAL) culture and cytologic findings are reported. RESULTS: Bronchoscopy was successful for removal of airway foreign bodies in 76% of animals (24/28 dogs and 2/5 cats), and in dogs was independent of duration of clinical signs or body size. One-third of thoracic radiographs lacked distinctive features of an airway foreign body, and therefore radiography was unable to predict the affected site. BAL fluid at the site of the foreign body contained more neutrophils and more often had intracellular bacteria than lavage fluid from a separate site. CONCLUSIONS AND CLINICAL IMPORTANCE: Bronchoscopy was successful in removing airway foreign bodies regardless of animal size or long duration of clinical signs. Results of this study confirm the utility of bronchoscopy with lavage in management of suspected foreign bodies, even in the absence of localizing radiographic findings.


Assuntos
Broncoscopia/veterinária , Doenças do Gato/cirurgia , Doenças do Cão/cirurgia , Corpos Estranhos/veterinária , Animais , Doenças do Gato/diagnóstico por imagem , Gatos , Doenças do Cão/diagnóstico por imagem , Cães , Corpos Estranhos/terapia , Radiografia , Estudos Retrospectivos
11.
J Drug Issues ; 40(2): 405-432, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21547240

RESUMO

This article examines the relationship between substance use and gender, sexuality, ethnicity, and nativity among 250 Asian American youths involved in the dance club/rave scene. We find distinct patterns of drug use differing by country of origin and ethnicity. However, contrary to some literature we do not find significant differences corresponding to immigration status, or number of years in the U.S. The most significant differences between subgroups are related to gender and sexuality: male respondents consume more drugs, more frequently than female respondents, and non-heterosexual respondents consume more than heterosexual respondents, with differing patterns for men's and women's sexual subgroups. There were also significant gender and sexuality differences with respect to the contexts in which respondents consume drugs, with the most significant differences being between heterosexual and non-heterosexual men. As we discuss, these findings illustrate the need for further investigation of drug use patterns of gender and sexuality within Asian American communities.

12.
J Radiol Prot ; 30(1): 73-83, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20220210

RESUMO

Concentrations of tritium in sea water and marine biota as reported over the last approximately 10 years from monitoring programmes carried out by this laboratory under contract to the UK Food Standards Agency are reviewed from three areas: near Cardiff; Sellafield; and Hartlepool. Near Cardiff, enhancement of concentration factors (CFs) above an a priori value of approximately 1 have already been studied, and attributed to compounds containing organically bound tritium in local radioactive waste discharges. Further data for Cardiff up to 2006 are reported in this note. Up to 2001, CFs increased to values of more than approximately 7000 in flounders and approximately 4000 in mussels, but have subsequently reduced; this variability could be due to changes in the organic constitution of compounds discharged. Near Sellafield and Hartlepool, enhancements to the tritium concentration factor are observed but they are relatively small compared with those near Cardiff. Near Sellafield, plaice and mussels appear to have a CF for tritium of approximately 10; in some cases concentrations of tritium in winkles are below detection limits and positively measured values indicate a CF of approximately 3. The variation could be due to mechanisms of uptake by the different organisms. Near Hartlepool there were only a few cases where tritium was positively measured. These data give a value of approximately 5 for the CF in plaice (on the basis of two samples); approximately 15 in winkles (eight samples); and > 45 in mussels (two samples). Any differences between the behaviours at Sellafield and Hartlepool would need to be confirmed by improved measurements. Possible causes are the organic composition of the effluent and differences in environmental behaviour and uptake by organisms near the two sites. These potential causes need further investigation. It is emphasised that results from tritium analyses are heavily method dependent; thus comparison with results from other programmes needs to take this into account. Further, the results for enhancement of CF will also depend on the definition of CF itself.


Assuntos
Trítio/farmacocinética , Poluentes Radioativos da Água/farmacocinética , Animais , Disponibilidade Biológica , Bivalves/metabolismo , Linguado/metabolismo , Gastrópodes/metabolismo , Centrais Elétricas , Resíduos Radioativos , Água do Mar/química , Distribuição Tecidual , Reino Unido
13.
Proc Math Phys Eng Sci ; 476(2241): 20200273, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33061790

RESUMO

Numerical results for the axially compressed cylindrical shell demonstrate the post-buckling response snaking in both the applied load and corresponding end-shortening. Fluctuations in load, associated with progressive axial formation of circumferential rings of dimples, are well known. Snaking in end-shortening, describing the evolution from a single dimple into the first complete ring of dimples, is a recent discovery. To uncover the mechanics behind these different phenomena, simple finite degree-of-freedom cellular models are introduced, based on hierarchical arrangements of simple unit cells with snapback characteristics. The analyses indicate two fundamentally different variants to this new form of snaking. Each cell has its own Maxwell displacement, which are either separated or overlap. In the presence of energetic background disturbance, the differences between these two situations can be crucial. If the Maxwell displacements of individual cells are separated, then buckling is likely to occur sequentially, with the system able to settle into different localized states in turn. Yet if Maxwell displacements overlap, then a global buckling pattern triggers immediately as a dynamic domino effect. We use the term Maxwell tipping point to identify the point of switching between these two behaviours.

14.
Sci Rep ; 10(1): 7932, 2020 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-32404966

RESUMO

Cassini's Grand Finale orbits provided for the first time in-situ measurements of Saturn's topside ionosphere. We present the Pedersen and Hall conductivities of the top near-equatorial dayside ionosphere, derived from the in-situ measurements by the Cassini Radio and Wave Plasma Science Langmuir Probe, the Ion and Neutral Mass Spectrometer and the fluxgate magnetometer. The Pedersen and Hall conductivities are constrained to at least 10-5-10-4 S/m at (or close to) the ionospheric peak, a factor 10-100 higher than estimated previously. We show that this is due to the presence of dusty plasma in the near-equatorial ionosphere. We also show the conductive ionospheric region to be extensive, with thickness of 300-800 km. Furthermore, our results suggest a temporal variation (decrease) of the plasma densities, mean ion masses and consequently the conductivities from orbit 288 to 292.

15.
Neuroscience ; 158(2): 441-55, 2009 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-18996447

RESUMO

gamma-Hydroxybutyrate (GHB) is a euphoric, prosocial and sleep inducing drug that binds with high affinity to its own GHB receptor site and also more weakly to GABA(B) receptors. GHB is efficacious in the treatment of narcolepsy and alcoholism, but heavy use can lead to dependence and withdrawal. Many effects of GHB (sedation, hypothermia, catalepsy) are mimicked by GABA(B) receptor agonists (e.g. baclofen). However other effects (euphoric and prosocial effects and a therapeutic effect in narcolepsy) are not. The present study used Fos immunohistochemistry to assess the neural activation produced in rat brain by medium to high doses of GHB (250, 500 and 1000 mg/kg) and a high dose of baclofen (10 mg/kg) that produced similar sedation to 500 mg/kg GHB. Results showed many common regions of activation with these two drugs including the supraoptic, paraventricular, median preoptic and ventral premammillary nuclei of the hypothalamus, the central nucleus of the amygdala, Edinger-Westphal nucleus, lateral parabrachial nucleus, locus coeruleus, and nucleus of the solitary tract. GHB (500 mg/kg), but not baclofen (10 mg/kg), induced significant Fos expression in the median raphe nucleus and lateral habenula, while a higher dose of GHB (1000 mg/kg) induced additional Fos expression in the islands of Calleja, dentate gyrus (polymorphic layer) and arcuate nucleus, and in various regions implicated in rapid and non-rapid eye movement sleep (laterodorsal tegmental nucleus, tuberomammillary nucleus and the ventrolateral and anterodorsal preoptic nuclei). Surprisingly, Fos immunoreactivity was not observed with either GHB or baclofen in reward-relevant regions such as the nucleus accumbens, striatum and ventral tegmental area. Overall these results indicate a distinctive signature of brain activation with GHB that may be only partly due to GABA(B) receptor effects. This confirms a unique neuropharmacological profile for GHB and indicates key neural substrates that may underlie its characteristic influence on sleep, body temperature, sociability and endocrine function.


Assuntos
Anestésicos Intravenosos/farmacologia , Baclofeno/farmacologia , Encéfalo/efeitos dos fármacos , Agonistas GABAérgicos/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas Oncogênicas v-fos/metabolismo , Oxibato de Sódio/farmacologia , Animais , Área Sob a Curva , Encéfalo/anatomia & histologia , Contagem de Células/métodos , Relação Dose-Resposta a Droga , Masculino , Atividade Motora/efeitos dos fármacos , Proteínas Oncogênicas v-fos/genética , Ratos , Ratos Wistar
16.
Proc Biol Sci ; 276(1655): 247-54, 2009 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-18796393

RESUMO

The extent to which animals other than humans can reason about physical problems is contentious. The benchmark test for this ability has been the trap-tube task. We presented New Caledonian crows with a series of two-trap versions of this problem. Three out of six crows solved the initial trap-tube. These crows continued to avoid the trap when the arbitrary features that had previously been associated with successful performances were removed. However, they did not avoid the trap when a hole and a functional trap were in the tube. In contrast to a recent primate study, the three crows then solved a causally equivalent but visually distinct problem--the trap-table task. The performance of the three crows across the four transfers made explanations based on chance, associative learning, visual and tactile generalization, and previous dispositions unlikely. Our findings suggest that New Caledonian crows can solve complex physical problems by reasoning both causally and analogically about causal relations. Causal and analogical reasoning may form the basis of the New Caledonian crow's exceptional tool skills.


Assuntos
Cognição , Corvos/fisiologia , Resolução de Problemas/fisiologia , Comportamento de Utilização de Ferramentas , Animais , Feminino , Masculino
17.
Science ; 155(3766): 1098-100, 1967 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-17812004

RESUMO

Infrared images of the thermal anomaly associated with the lunar crater Tycho were obtained during the lunar night after Tycho had ceased to be illuminated by the Suin for as long as 97 hours. In agreement with results of previous studies, these measurements show that the crater is warmer than its surroundings during the lunar night, and that the temperature of the thermal anomaly gradually decreases with time, being no longer detectable after new moon. This work provides strong evidence that the steeper crater walls facing the Sun before local sunset are warmer throughout the cooling phase, and that the Tycho anomaly is thus produced by solar, rather than internal, heat.

18.
Science ; 161(3839): 365-6, 1968 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-17776739

RESUMO

The presence of abundant limonite on Mars has long been the subject of controversy. Some advocates of abundant limonite also suggest that the albedo differences between Martian light and dark areas are caused by different sizes of particles in those areas. We show that the relative albedo is reversed from the blue to the red for samples of limonite with particles of different sizes. Observations of Mars reveal no blue-red albedo reversal between the light and dark areas. Consequently, the hypothesis of particle size control of albedo is incompatible with the presence of abundant limonite on Mars.

19.
Science ; 169(3948): 865-6, 1970 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-17750058

RESUMO

Information diagnostic of general rock type is available as a well-defined emission maximum (related to the Christiansen frequency), rather than as contrast-depleted minima, in the infrared spectra of particulate solids. The amount of spectral information varies directly with the sharpness of the thermal gradient at the sample surface. Lunar thermal conditions optimize this gradient, making the moon an excellent target for remote sensing.

20.
Science ; 196(4297): 1466-7, 1977 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-17776927

RESUMO

Pairs of females that remain together from one year to the next are associated with the presence of supernormal clutches in western gull nests. Intervals between laying of eggs in supernormal clutches are less than those found in normal clutches, a result indicating both females in a pair contribute to the clutch. Most eggs in supernormal clutches are infertile. The pairs of females occupy territories that are not shared with a resident male. In three homosexual pairs one of the females exhibited behaviors normally ascribed only to males.

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