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1.
Bull Math Biol ; 81(10): 4233-4250, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31376062

RESUMEN

A population is considered stationary if the growth rate is zero and the age structure is constant. It thus follows that a population is considered non-stationary if either its growth rate is nonzero and/or its age structure is non-constant. We propose three properties that are related to the stationary population identity (SPI) of population biology by connecting it with stationary populations and non-stationary populations which are approaching stationarity. One of these important properties is that SPI can be applied to partition a population into stationary and non-stationary components. These properties provide deeper insights into cohort formation in real-world populations and the length of the duration for which stationary and non-stationary conditions hold. The new concepts are based on the time gap between the occurrence of stationary and non-stationary populations within the SPI framework that we refer to as Oscillatory SPI and the Amplitude of SPI.

2.
Ecol Appl ; : e01991, 2019 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-31400182

RESUMEN

In the six decades since 1960, the oriental fruit fly, Bactrocera dorsalis (Hendel), has been announced successfully eradicated in California by the U.S. Department of Agriculture a total of 564 times. This includes eradication declarations in one city a total of 25 different years, in 12 cities 8-19 different years, and in 101 cities 2-7 different years. We here show that the false negatives in declaring elimination success hinge on the easily achieved regulatory criteria, which have virtually guaranteed the failure of complete extirpation of this pest. Analyses of the time series of fly detection over California placed on a grid of 100-km2 cells revealed (1) partial success of the eradication program in controlling the invasion of the oriental fruit fly; (2) low prevalence of the initial detection in these cells is often followed by high prevalence of recurrences; (3) progressively shorter intervals between years of consecutive detections; and (4) high likelihood of early-infested cells also experiencing the most frequent outbreaks. Facing the risk of recurrent invasions, such short-term eradication programs have only succeeded annually according to the current regulatory criteria but have failed to achieve the larger goal of complete extirpation of the oriental fruit fly. Based on the components and running costs of the current programs, we further estimated the efficiency of eradication programs with different combinations of eradication radius, duration, and edge impermeability in reducing invasion recurrences and slowing the spread of the oriental fruit fly. We end with policy implications including the need for agricultural agencies worldwide to revisit eradication protocols in which monitoring and treatments are terminated when the regulatory criteria for declaring eradication are met. Our results also have direct implications to invasion biologists and agriculture policy makers regarding long-term risks of short-term expediency.

3.
PLoS One ; 14(7): e0219518, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31344046

RESUMEN

Using a well-established model species for demographic, behavioural and aging research, the Mediterranean fruit fly (Ceratitis capitata), we explored whether nutritional stress early in adult life affects the sexual performance and survival in older ages. To do so we established two different protein starvation (PS) protocols that included the elimination of proteinaceous diet either before or after sexual maturity of male medflies. The frequency of sexual signalling and the age of death were daily recorded. Sexual signalling is directly related with male mating success in this model system. PS early in adult life results in high mortality rates (similar to sugar-only fed males), which are gradually restored in more advanced ages. Provision of a proteinaceous diet following early-life PS increases straightaway male sexual signalling to levels similar with those having continuous access to proteinaceous diet. Switching diet regimes from a protein-free to a protein-rich one progressively compensates mortality rates. Apparently, males prioritize sexual signalling over lifespan. PS after attaining sexual maturity significantly reduces both longevity and sexual performance. Access to protein only early in life is insufficient to support lifetime energy-consuming behaviours such as sexual signalling. Continuous access to a proteinaceous diet determines both lifetime sexual performance and longevity. Early in life PS males prioritize the allocation of nutritional elements, when available, in sexual activities over soma-maintenance.

4.
Sci Rep ; 9(1): 10704, 2019 Jul 24.
Artículo en Inglés | MEDLINE | ID: mdl-31341198

RESUMEN

The ability of an animal to withstand periods of food deprivation is a key driver of invasion success (biodiversity), adaptation to new conditions, and a crucial determinant of senescence in populations. Starvation resistance (SR) is a highly plastic trait and varies in relation to environmental and genetic variables. However, beyond Drosophila, SR has been studied poorly. Exploiting an interesting model species in invasion and ageing studies-the Mediterranean fruit fly (Ceratitis capitata)- we investigated how age, food and gender, shape SR in this species. We measured SR in adults feeding in rich and poor dietary conditions, which had been reared either on natural hosts or artificial larval diet, for every single day across their lifespan. We defined which factor is the most significant determinant of SR and we explored potential links between SR and ageing. We found that SR declines with age, and that age-specific patterns are shaped in relation to adult and larval diet. Females exhibited higher SR than males. Age and adult diet were the most significant determinants of SR, followed by gender and the larval diet. Starvation resistance proved to be a weak predictor of functional ageing. Possible underlying mechanisms, ecological and gerontological significance and potential applied benefits are discussed.

5.
Ecology ; 100(5): e02682, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-31018019

RESUMEN

Biological invasions are increasingly being considered important spatial processes that drive global changes, threatening biodiversity, regional economies, and ecosystem functions. A unifying conceptual model of the invasion dynamics could serve as a useful tool for comparison and classification of invasion processes involving different species across large geographic ranges. By dividing these geographic ranges that are subject to invasions into discrete spatial units, we here conceptualize the invasion process as the transition from pristine to invaded spatial units. We use California cities as the spatial units and a long-term database of invasive tropical tephritids to characterize the invasion patterns. A new life-table method based on insect demography, including the progression model of invasion stage transition and the species-specific partitioning model of multispecies invasions, was developed to analyze the invasion patterns. The progression model allows us to estimate the probability and rate of transition for individual cities from pristine to infested stages and subsequently differentiate the first year of detection from detection recurrences. Importantly, we show that the interval of invasive tephritid recurrence in a city declines with increasing invasion stages of the city. The species-specific partitioning model revealed profound differences in invasion outcome depending on which tephritid species was first detected (and then locally eradicated) in the early stage of invasion. Taken together, we discuss how these two life-table invasion models can cast new light on existing invasion concepts; in particular, on formulating invasion dynamics as the state transition of cities and partitioning species-specific roles during multispecies invasions. These models provide a new set of tools for predicting the spatiotemporal progression of invasion and providing early warnings of recurrent invasions for efficient management.

6.
J Neuroeng Rehabil ; 15(1): 83, 2018 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-30227864

RESUMEN

BACKGROUND: Transcranial direct current stimulation (tDCS) is an effective neuromodulation adjunct to repetitive motor training in promoting motor recovery post-stroke. Finger tracking training is motor training whereby people with stroke use the impaired index finger to trace waveform-shaped lines on a monitor. Our aims were to assess the feasibility and safety of a telerehabilitation program consisting of tDCS and finger tracking training through questionnaires on ease of use, adverse symptoms, and quantitative assessments of motor function and cognition. We believe this telerehabilitation program will be safe and feasible, and may reduce patient and clinic costs. METHODS: Six participants with hemiplegia post-stroke [mean (SD) age was 61 (10) years; 3 women; mean (SD) time post-stroke was 5.5 (6.5) years] received five 20-min tDCS sessions and finger tracking training provided through telecommunication. Safety measurements included the Digit Span Forward Test for memory, a survey of symptoms, and the Box and Block test for motor function. We assessed feasibility by adherence to treatment and by a questionnaire on ease of equipment use. We reported descriptive statistics on all outcome measures. RESULTS: Participants completed all treatment sessions with no adverse events. Also, 83.33% of participants found the set-up easy, and all were comfortable with the devices. There was 100% adherence to the sessions and all recommended telerehabilitation. CONCLUSIONS: tDCS with finger tracking training delivered through telerehabilitation was safe, feasible, and has the potential to be a cost-effective home-based therapy for post-stroke motor rehabilitation. TRIAL REGISTRATION: NCT02460809 (ClinicalTrials.gov).

7.
Clin Case Rep ; 6(5): 792-797, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29744058

RESUMEN

In a 46-year-old female 6 months poststroke who presented with minimal paretic hand function, repetitive transcranial magnetic stimulation (rTMS), and exercises considerably improved her function beyond that accomplished with conventional rehabilitation. However, intermittent rTMS (2 sessions/week) was required to sustain the benefits. Research is required to determine the critical frequency of intermittent rTMS needed to sustain functional gains long term.

8.
Phys Ther ; 97(3): 310-319, 2017 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-28426872

RESUMEN

Although much research has been done on repetitive transcranial magnetic stimulation (rTMS) in chronic stroke, only sparse research has been done in acute stroke despite the particularly rich potential for neuroplasticity in this stage. We attempted a preliminary clinical trial in one active, high-quality inpatient rehabilitation facility (IRF) in the -United States. But after enrolling only 4 patients in the grant period, the study was stopped because of low enrollment. The purpose of this paper is to offer a perspective describing the important physiologic rationale for including rTMS in the early phase of stroke, the reasons for our poor patient enrollment in our attempted study, and recommendations to help future studies succeed. We conclude that, if scientists and clinicians hope to enhance stroke outcomes, more attention must be directed to leveraging conventional rehabilitation with neuromodulation in the acute phase of stroke when the capacity for neuroplasticity is optimal. Difficulties with patient enrollment must be addressed by reassessing traditional inclusion and exclusion criteria. Factors that shorten patients' length of stay in the IRF must also be reassessed at all policy-making levels to make ethical decisions that promote higher functional outcomes while retaining cost consciousness.


Asunto(s)
Rehabilitación de Accidente Cerebrovascular , Accidente Cerebrovascular/fisiopatología , Estimulación Magnética Transcraneal , Humanos , Selección de Paciente , Accidente Cerebrovascular/complicaciones
9.
Inorg Chem ; 56(5): 2722-2735, 2017 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-28225607

RESUMEN

ß-Diketiminato copper(I) complexes play important roles in bioinspired catalytic chemistry and in applications to the materials industry. However, it has been observed that these complexes are very susceptible to disproportionation. Coordinating solvents or Lewis bases are typically used to prevent disproportionation and to block the coordination sites of the copper(I) center from further decomposition. Here, we incorporate this coordination protection directly into the molecule in order to increase the stability and reactivity of these complexes and to discover new copper(I) binding motifs. Here we describe the synthesis, structural characterization, and reactivity of a series of unsymmetrical N-aryl-N'-alkylpyridyl ß-diketiminato copper(I) complexes and discuss the structures and reactivity of these complexes with respect to the length of the pyridyl arm. All of the aforementioned unsymmetrical ß-diketiminato copper(I) complexes bind CO reversibly and are stable to disproportionation. The binding ability of CO and the rate of pyridyl ligand decoordination of these copper(I) complexes are directly related to the competition between the degree of puckering of the chelate system and the steric demands of the N-aryl substituent.

10.
J Math Biol ; 75(4): 973-984, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-28213681

RESUMEN

Residual demography is a recent concept that has proved to be a useful tool to gain insights about the age distributions of wild populations, especially insects. We develop an operator equation that permits the derivation of functionals of the age distribution in wild populations, such as mean age, within the framework of residual demography. Our method combines information from an observed captive cohort, which consists of subjects that are sampled from the wild with unknown ages and then raised in the laboratory until death, and from a reference cohort that consists of subjects raised in the laboratory since birth of the same population. Targeting functionals such as the mean of the wild age distribution has the advantage of avoiding strong assumptions such as stationarity and stability of the population that one would need when targeting the entire survival distribution in the wild. Our main result characterizes the existence of a solution of the operator equation that yields the functional of interest. The proposed method also enjoys straightforward and easy implementation. A data example is included illustrating an application, where one aims to attain the mean age of mosquitoes in the wild, based on seasonal captive cohorts from Greece and a simulated reference cohort, separately for various summer and fall months.


Asunto(s)
Animales Salvajes , Modelos Biológicos , Distribución por Edad , Animales , Simulación por Computador , Culex , Ecosistema , Análisis de los Mínimos Cuadrados , Modelos Lineales , Conceptos Matemáticos , Modelos Estadísticos , Estaciones del Año
11.
Artículo en Inglés | MEDLINE | ID: mdl-29435516

RESUMEN

Stroke characteristics vary widely between individuals making it difficult to assess the value of stroke rehabilitation interventions. To eliminate inter-subject variability, this study used an N-of-1 randomized, controlled design to explore the efficacy of repetitive transcranial magnetic stimulation (rTMS) in one unique individual with pontine stroke. We hypothesized that five days of active 6-Hz primed, low-frequency rTMS to the contralesional primary motor area (M1), combined with finger movement tracking training, would accomplish greater gains in hand function than sham rTMS combined with tracking training. We assessed hand function (Box and Block test and finger tracking test), cortical activation (laterality index during functional magnetic resonance imaging), and cortical excitability (interhemispheric inhibition testing (IHI) with transcranial magnetic stimulation (TMS)). Diffusion tensor imaging (DTI) assessed the integrity of his corticospinal tracts at baseline. Results showed no improvement in the Box and Block or finger tracking tests, unreliable IHI findings, and no change in laterality index following active rTMS. DTI suggested truncation of the left corticospinal tract (CST) at the pons. His non-dexterous hand movements combined with no elicitable motor evoked potentials with TMS to ipsilesional M1 and his DTI findings lead us to speculate a reticulospinal mechanism for preserving his rudimentary paretic hand control. We conclude that rTMS combined with tracking training was not effective in the absence of CST pathways and that research is needed to confirm markers of reticulospinal function in humans as an alternative to defective CST function.

12.
Taiwan J Obstet Gynecol ; 55(5): 724-727, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27751424

RESUMEN

OBJECTIVE: Placental site trophoblastic tumor (PSTT) is rare and is characterized by a slow growth. The objective of this report is to present a case of PSTT associated with irregular vaginal spotting that occurred 1 year after normal vaginal delivery. CASE REPORT: This report provides interesting ultrasound, hysteroscopy, and histology findings of PSTT. It is difficult to make a clinical diagnosis of PSTT at an early stage. Without the use of immunohistochemical analysis, PSTT may evade histological detection. An operative hysteroscopy using electrocauterization reduces active bleeding during the removal of PSTT with markedly engorged tumor vessels. CONCLUSION: Transvaginal sonography using color Doppler imaging plays a vital role in identifying residual PSTT with microscopic infiltration to the myometrium and a negative serum ß-human chorionic gonadotropin level.


Asunto(s)
Manejo de la Enfermedad , Complicaciones Neoplásicas del Embarazo , Tumor Trofoblástico Localizado en la Placenta/diagnóstico , Ultrasonografía Prenatal/métodos , Neoplasias Uterinas/diagnóstico , Adulto , Biopsia , Diagnóstico Diferencial , Endosonografía , Femenino , Humanos , Histerectomía/métodos , Recién Nacido , Tomografía de Emisión de Positrones , Embarazo , Tumor Trofoblástico Localizado en la Placenta/cirugía , Ultrasonografía Doppler en Color , Neoplasias Uterinas/cirugía , Vagina
13.
PLoS One ; 11(7): e0158468, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27383645

RESUMEN

Despite the importance of trauma in healthspan and lifespan in humans as well as in non-human species, with one important exception the literature in both gerontology and ecology contains virtually no experimental demographic studies concerned with trauma in any species. We used dietary manipulation [full diet (F) versus sugar-only (S)] to produce four levels of frailty in 55-day old tephritid fruit flies (Anastrepha ludens) that were then subject to the trauma of cage transfer stress (n = 900/sex in each of the 4 treatments). The key results included the following: (1) there is a trauma effect caused by the transfer that depends on previous diet before transfer, new diet after transfer and gender of the fly; (2) males are more vulnerable than females; (3) if initial diet was F, flies are relatively immune against the trauma, and the subsequent diet (F or S) does not matter; (4) however if initial diet was S, then the effect of the trauma depends largely on the diet after the transfer; (5) flies transferred from S to F diets do very well in terms of remaining longevity (i.e. greatest remaining longevity), while flies transferred from S to S diet do poorly (i.e. shortest remaining longevity). We discuss both the strengths and weaknesses of this study and implications of the results.


Asunto(s)
Dieta , Longevidad/fisiología , Estrés Fisiológico , Tephritidae/fisiología , Algoritmos , Animales , Conducta Animal , Restricción Calórica , Femenino , Fertilidad/fisiología , Masculino , Modelos de Riesgos Proporcionales , Factores Sexuales
14.
Neuromodulation ; 19(8): 838-847, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27333364

RESUMEN

OBJECTIVE: Reliable transcranial magnetic stimulation (TMS) measures for probing corticomotor excitability are important when assessing the physiological effects of noninvasive brain stimulation. The primary objective of this study was to examine test-retest reliability of an interhemispheric inhibition (IHI) index measurement in stroke. MATERIALS AND METHODS: Ten subjects with chronic stroke (≥6 months) completed two IHI testing sessions per week for three weeks (six testing sessions total). A single investigator measured IHI in the contra-to-ipsilesional primary motor cortex direction and in the opposite direction using bilateral paired-pulse TMS. Weekly sessions were separated by 24 hours with a 1-week washout period separating testing weeks. To determine if motor-evoked potential (MEP) quantification method affected measurement reliability, IHI indices computed from both MEP amplitude and area responses were found. Reliability was assessed with two-way, mixed intraclass correlation coefficients (ICC(3,k) ). Standard error of measurement and minimal detectable difference statistics were also determined. RESULTS: With the exception of the initial testing week, IHI indices measured in the contra-to-ipsilesional hemisphere direction demonstrated moderate to excellent reliability (ICC = 0.725-0.913). Ipsi-to-contralesional IHI indices depicted poor or invalid reliability estimates throughout the three-week testing duration (ICC= -1.153-0.105). The overlap of ICC 95% confidence intervals suggested that IHI indices using MEP amplitude vs. area measures did not differ with respect to reliability. CONCLUSIONS: IHI indices demonstrated varying magnitudes of reliability irrespective of MEP quantification method. Several strategies for improving IHI index measurement reliability are discussed.


Asunto(s)
Lateralidad Funcional/fisiología , Corteza Motora/fisiología , Inhibición Neural/fisiología , Accidente Cerebrovascular/terapia , Estimulación Magnética Transcraneal/métodos , Anciano , Anciano de 80 o más Años , Análisis de Varianza , Potenciales Evocados Motores , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proyectos Piloto , Reproducibilidad de los Resultados , Índice de Severidad de la Enfermedad
16.
Res Dev Disabil ; 47: 154-64, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26426515

RESUMEN

This study analyzed the relationship between electrophysiological responses to transcranial magnetic stimulation (TMS), finger tracking accuracy, and volume of neural substrate in children with congenital hemiparesis. Nineteen participants demonstrating an ipsilesional motor-evoked potential (MEP) were compared with eleven participants showing an absent ipsilesional MEP response. Comparisons of finger tracking accuracy from the affected and less affected hands and ipsilesional/contralesional (I/C) volume ratio for the primary motor cortex (M1) and posterior limb of internal capsule (PLIC) were done using two-sample t-tests. Participants showing an ipsilesional MEP response demonstrated superior tracking performance from the less affected hand (p=0.016) and significantly higher I/C volume ratios for M1 (p=0.028) and PLIC (p=0.005) compared to participants without an ipsilesional MEP response. Group differences in finger tracking accuracy from the affected hand were not significant. These results highlight differentiating factors amongst children with congenital hemiparesis showing contrasting MEP responses: less affected hand performance and preserved M1 and PLIC volume. Along with MEP status, these factors pose important clinical implications in pediatric stroke rehabilitation. These findings may also reflect competitive developmental processes associated with the preservation of affected hand function at the expense of some function in the less affected hand.


Asunto(s)
Encéfalo/patología , Potenciales Evocados Motores/fisiología , Dedos/fisiopatología , Cápsula Interna/fisiopatología , Corteza Motora/fisiopatología , Paresia/fisiopatología , Adolescente , Niño , Femenino , Dedos/fisiología , Lateralidad Funcional , Mano/fisiología , Mano/fisiopatología , Humanos , Cápsula Interna/patología , Imagen por Resonancia Magnética , Masculino , Corteza Motora/patología , Paresia/congénito , Paresia/patología , Paresia/rehabilitación , Estimulación Magnética Transcraneal
18.
Brain Stimul ; 8(6): 1074-84, 2015 Nov-Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26198365

RESUMEN

BACKGROUND: Preceding low-frequency repetitive transcranial magnetic stimulation (rTMS) with a bout of high-frequency rTMS called priming potentiates the after-effects of the former in healthy adults. The utility of primed rTMS in stroke remains under-explored despite its theoretical benefits in enhancing cortical excitability and motor function. OBJECTIVE: To ascertain the efficacy of priming in chronic stroke by comparing changes in cortical excitability and paretic hand function following three types of primed low-frequency rTMS treatments. METHODS: Eleven individuals with chronic stroke participated in this repeated-measures study receiving three treatments to the contralesional primary motor cortex in randomized order: 6 Hz primed 1 Hz rTMS, 1 Hz primed 1 Hz rTMS, and sham 6 Hz primed active 1 Hz rTMS. Within- and between-treatment differences from baseline in cortical excitability and paretic hand function from baseline were analyzed using mixed effects linear models. RESULTS: 6 Hz primed 1 Hz rTMS produced significant within-treatment differences from baseline in ipsilesional cortical silent period (CSP) duration and short-interval intracortical inhibition. Compared to 1 Hz priming and sham 6 Hz priming of 1 Hz rTMS, active 6 Hz priming generated significantly greater decreases in ipsilesional CSP duration. These heightened effects were not observed for intracortical facilitation or interhemispheric inhibition excitability measures. CONCLUSION: Our findings demonstrate the efficacy of 6 Hz primed 1 Hz rTMS in probing homeostatic plasticity mechanisms in the stroke brain as best demonstrated by differences CSP duration and SICI from baseline. Though 6 Hz priming did not universally enhance cortical excitability across measures, our findings pose important implications in non-invasive brain stimulation application in stroke rehabilitation.


Asunto(s)
Accidente Cerebrovascular/diagnóstico , Accidente Cerebrovascular/terapia , Estimulación Magnética Transcraneal/métodos , Anciano , Anciano de 80 o más Años , Enfermedad Crónica , Estudios Cruzados , Método Doble Ciego , Potenciales Evocados Motores/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Corteza Motora/fisiología , Accidente Cerebrovascular/fisiopatología , Resultado del Tratamiento
20.
Physiol Entomol ; 40(1): 65-71, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25709143

RESUMEN

Hypotheses exploring the influence of dietary conditions on the life history trade-off between survival and reproductive success are extensively tested in female insects, but are rarely explored in males. Here, the impact of dietary quality and female access on age-specific reproduction and survival of male Mexican fruit flies, Anastrepha ludens Loew (Diptera: Tephritidae), are examined. There is a clear cost of female access for males with access to dietary protein, measurable as a decrease in life expectancy, which is further influenced by the age when females are introduced. A protein deficient diet reduces the lifespan benefit of virginity and masks the detrimental effect of female access on male life expectancy. Dietary protein is not necessary for reproductive success, but access to protein at eclosion improves the lifetime reproductive success of males compared to when it is delayed. Overall, reproductive success diminishes as the male flies age, regardless of the dietary conditions, providing evidence for reproductive senescence in males. Delaying the males' access to a protein source fails to influence the negative effect of age on reproductive ability. Because age specific reproductive rates decline with age, regardless of diet, male fitness does not benefit from lifespan extension. Therefore, males can be expected to allocate available resources towards reproductive effort in favour of extended lifespan, regardless of mate and protein availability.

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