582 research outputs found
The effect of environmental factors on hatching, moulting, and survival of zoeal larvae of the blue crab, Callinectes sapidus Rathbun
The blue crab constitutes a major fishery of the Chesapeake Bay amount- ing in 1939 to about fifty-seven million pounds. During the past two decades there have been pronounced fluctuations in the catches attributed to weather conditions and to industrial practices. Thus, from 1939 to 1941 the crab catch declined over 50% in Maryland and about 40% in Virginia (U. S. Fishery Statistics, \u2741). Since then there has been a marked increase in production.
For successful management of the fishery, further biological information is required to provide a sound basis for conservation policy. The particular biological problem with which we are concerned here is contained in the question, Where or under what environmental conditions can egg-bearing or sponge crabs produce larvae that may be expected to undergo normal development? An answer to this question provides a basis for selection of crab sanctuaries that may help to protect the brood stock (figure 1)
Investigating prenatal perceived support as protective factor against adverse birth outcomes: a community cohort study.
Studies show that prenatal maternal anxiety may act as a risk factor for adverse birth outcomes, whilst prenatal social support may rather act as a protective factor. However, studies examining prenatal anxiety symptoms, prenatal perceived support, and neonatal and/or obstetric outcomes are lacking.
This study investigated whether, in a community sample, prenatal perceived support: (1) had a protective influence on birth outcomes (gestational age (GA), birthweight (BW), 5-minute Apgar score, and mode of delivery); (2) acted as a protective factor, moderating the relationship between anxiety symptoms and the aforementioned birth outcomes.
During their third trimester of pregnancy, 182 nulliparous child-bearers completed standardized questionnaires of anxiety (HADS-A) and perceived support (MOS-SSS). Birth outcomes data was extracted from medical records.
(1) Perceived support did not significantly predict any birth outcomes. However, perceived tangible support - MOS-SSS subscale assessing perceived material/financial aid - significantly positively predicted the 5-minute Apgar score. (2) Perceived support did not significantly moderate the relationship between anxiety symptoms and birth outcomes. However, perceived tangible support significantly moderated the relationship between anxiety symptoms and the 5-minute Apgar score.
When experienced within non-clinical thresholds, prenatal anxiety symptoms do not increase the risk of adverse neonatal and obstetric outcomes when perceived support is present
Integrated hydrological modelling of a managed coastal Mediterranean wetland (Rhone delta, France): initial calibration
This paper presents a model of a heavily managed coastal Mediterranean wetland. The hydrosystem studied , called ``Ile de Camargue', is the central part of the Rhone river delta. It comprises flat agricultural drainage basins, marshes, and shallow brackish lagoons whose connection to the sea is managed. This hydrosystem is subject to strong natural hydrological variability due to the combination of a Mediterranean climate and the artificial hydrological regime imposed by flooded rice cultivation. To quantify the hydrological balance at different spatial and temporal scales, a simplified model is developed — including the basin and the lagoons — using a time step that enables the temporal dynamic to be reproduced that is adapted to data availability. This modelling task takes into account the functioning of the natural and anthropogenic components of the hydrosystem. A conceptual approach is used for modelling drainage from the catchment, using a GIS to estimate water input for rice irrigation. The lagoon system is modelled using a two-dimensional finite element hydrodynamic model. Simulated results from the hydrodynamic model run under various hydro-climatic forcing conditions (water level, wind speed and direction, sea connection) are used to calculate hydraulic exchanges between lagoon sub units considered as boxes. Finally, the HIC ('Hydrologie de l’Ile de Camargue') conceptual model is applied to simulate the water inputs and exchanges between the different units, together with the salt balance in the hydrosystem during a calibration period.</p> <p style='line-height: 20px;'><b>Keywords: </b>water management,conceptual hydrological model, hydrodynamic model, box model, GIS, Rhone delta, Camargue
Maternal Mental Health Symptom Profiles and Infant Sleep: A Cross-Sectional Survey.
The distinct influence of different, but comorbid, maternal mental health (MMH) difficulties (postpartum depression, anxiety, childbirth-related posttraumatic stress disorder) on infant sleep is unknown, although associations between MMH and infant sleep were reported. This cross-sectional survey aimed: (1) to examine associations between MMH symptoms and infant sleep; (2) to extract data-driven maternal MMH symptom profiles from MMH symptoms; and (3) to investigate the distinct influence of these MMH symptom profiles on infant sleep when including mediators and moderators. Mothers of 3-12-month-old infants (n = 410) completed standardized questionnaires on infant sleep, maternal perception of infant negative emotionality, and MMH symptoms. Data was analyzed using: (1) simple linear regressions; (2) factor analysis; and (3) structural equation modelling. MMH symptoms were all negatively associated with nocturnal sleep duration and only postpartum depression and anxiety symptoms were associated with night waking. Three MMH symptom profiles were extracted: depressive, anxious, and birth trauma profiles. Maternal perception of infant negative emotionality mediated the associations between the depressive or anxious profiles and infant sleep but only for particular infant ages or maternal education levels. The birth trauma profile was not associated with infant sleep. The relationships between MMH and infant sleep may involve distinct mechanisms contingent on maternal symptomatology
Multi-hydrogenated compounds monitoring in optical fibre manufacturing process by photoacoustic spectroscopy
Sub-ppm hydrogen chloride (HCl) and water vapour (H2O) monitoring using photoacoustic spectroscopy in optical fibre manufacturing is reported. The development and performance of a sensor based on an acoustic resonant configuration is described, and on-site measurements are presented. Two DFB lasers emitting in the 1370nm and 1740nm range were used for the detection of H2O and HCl, respectively. A detection limit (defined for a SNR=3) of 60ppb for HCl and 40ppb for H2O was achieved. Contamination sources of the carrier gas used for the fibre preform manufacturing are identified and discusse
The Lausanne Infant Crying Stress Paradigm: Validation of an Early Postpartum Stress Paradigm with Women at Low vs. High Risk of Childbirth-Related Posttraumatic Stress Disorder.
Stress reactivity is typically investigated in laboratory settings, which is inadequate for mothers in maternity settings. This study aimed at validating the Lausanne Infant Crying Stress Paradigm (LICSP) as a new psychosocial stress paradigm eliciting psychophysiological stress reactivity in early postpartum mothers (n = 52) and to compare stress reactivity in women at low (n = 28) vs. high risk (n = 24) of childbirth-related posttraumatic stress disorder (CB-PTSD). Stress reactivity was assessed at pre-, peri-, and post-stress levels through salivary cortisol, heart rate variability (high-frequency (HF) power, low-frequency (LF) power, and LF/HF ratio), and perceived stress via a visual analog scale. Significant time effects were observed for all stress reactivity outcomes in the total sample (all p < 0.01). When adjusting for perceived life threat for the infant during childbirth, high-risk mothers reported higher perceived stress (p < 0.001, d = 0.91) and had lower salivary cortisol release (p = 0.023, d = 0.53), lower LF/HF ratio (p < 0.001, d = 0.93), and marginally higher HF power (p = 0.07, d = 0.53) than low-risk women. In conclusion, the LICSP induces subjective stress and autonomic nervous system (ANS) reactivity in maternity settings. High-risk mothers showed higher perceived stress and altered ANS and hypothalamic-pituitary-adrenal reactivity when adjusting for infant life threat. Ultimately, the LICSP could stimulate (CB-)PTSD research
Can airborne ultrasound monitor bubble size in chocolate?
Aerated chocolate products consist of solid chocolate with the inclusion of bubbles and are a popular consumer product in many countries. The volume fraction and size distribution of the bubbles has an effect on their sensory properties and manufacturing cost. For these reasons it is important to have an online real time process monitoring system capable of measuring their bubble size distribution. As these products are eaten by consumers it is desirable that the monitoring system is non contact to avoid food contaminations. In this work we assess the feasibility of using an airborne ultrasound system to monitor the bubble size distribution in aerated chocolate bars. The experimental results from the airborne acoustic experiments were compared with theoretical results for known bubble size distributions using COMSOL Multiphysics. This combined experimental and theoretical approach is used to develop a greater understanding of how ultrasound propagates through aerated chocolate and to assess the feasibility of using airborne ultrasound to monitor bubble size distribution in these systems. The results indicated that a smaller bubble size distribution would result in an increase in attenuation through the product
Activation of JNK1 contributes to dystrophic muscle pathogenesis
AbstractDuchenne Muscular Dystrophy (DMD) originates from deleterious mutations in the dystrophin gene, with a complete loss of the protein product [1, 2]. Subsequently, the disease is manifested in severe striated muscle wasting and death in early adulthood [3]. Dystrophin provides a structural base for the assembly of an integral membrane protein complex [4]. As such, dystrophin deficiency leads to an altered mechanical integrity of the myofiber and a predisposition to contraction-induced damage [5–7]. However, the development of myofiber degeneration prior to an observed mechanical defect has been documented in various dystrophic models [8, 9]. Although activation of a detrimental signal transduction pathway has been suggested as a probable cause, a specific cellular cascade has yet to be defined. Here, it is shown that murine models of DMD displayed a muscle-specific activation of JNK1. Independent activation of JNK1 resulted in defects in myotube viability and integrity in vitro, similar to a dystrophic phenotype. In addition, direct muscle injection of an adenoviral construct containing the JNK1 inhibitory protein, JIP1, dramatically attenuated the progression of dystrophic myofiber destruction. Taken together, these results suggest that a JNK1-mediated signal cascade is a conserved feature of dystrophic muscle and contributes to the progression of the disease pathogenesis
Microfabrication of position reference patterns onto glass microscope slides for high-accurate analysis of dynamic cellular events
Los portaobjetos de microscopio se utilizan ampliamente como sustratos base in situ para la realización de diversos sistemas o elementos microfabricados. Para estos fines, el proceso de microfabricación consiste en transferir un diseño predefinido sobre el sustrato correspondiente a una lámina de vidrio utilizada como portaobjetos de microscopio. Este proceso se conoce como “patterning”, que es una técnica que también se puede utilizar en la transferencia de diseños específicos que permite la recuperación de una región de interés (ROI) bajo el microscopio. En estos casos, aparecen dos desafíos principales: 1) Las perturbaciones en la transmisión de la luz deben permanecer mínimas para mantener la alta calidad de observación del objeto de interés bajo el microscopio. 2) El tamaño del patrón debe ser entonces suficientemente pequeño, pero, sin embargo, mayor que el límite de difracción para ser observable satisfactoriamente para propósitos de posicionamiento. En este artículo presentamos los procedimientos involucrados en la microfabricación de Patrones Pseudo-Periódicos (PPP) los cuales encriptan la posición absoluta de un área extendida. Esos patrones están embebidos en placas de Pétri para permitir la recuperación absoluta y de alta precisión de una ROI, al igual que su orientación. La microfabricación presentada se basa en una técnica conocida como “liftoff” que, tras el ajuste de parámetros, permite la obtención de PPP cumpliendo los dos requisitos anteriormente mencionados. Los resultados corresponden a la realización de PPP en portaobjetos de vidrio y compuesto por puntos laterales de 2μm hechos de aluminio con un grosor de 30nm.Glass microscopes slides are widely used as in situ base-substrates carrying diverse micro-fabricated systems or elements. For such purposes, the micro-fabrication process consists in transferring a pre-defined design onto the substrate made of a glass microscope slide. This is known as patterning, which is a technique that can also be used in transferring specific designs that allows region of interest (ROI) recovery under the microscope. In those cases, two main challenges appear: 1) Disturbances in light transmission should remain minimum to keep the high quality of observation of the object of interest under the microscope. 2) The pattern-size should then be small enough but, however, larger than the diffraction limit to be observable satisfactorily for positioning purposes. In this article, we present the procedures involved in the microfabrication of Pseudo-Periodic Patterns (PPP) encrypting the absolute position of an extended area. Those patterns are embedded in Pétri dishes in order to allow the highaccurate retrieval of absolute position and orientation. The presented microfabrication is based in a technique known as lift-off, which after parameter adjustment, allows the obtaining of PPP fulfilling the two previously mentioned requirements. The results report on PPP realized on glass microscope slides and composed by 2µm side dots made of aluminum with a thickness of 30nm
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