Although cold hardiness is known to be a major determinant of tree species distribution, its dyna... more Although cold hardiness is known to be a major determinant of tree species distribution, its dynamics and the factors that regulate it remain poorly understood. Variation in cold hardiness and carbohydrate concentration, from dormancy induction until bud burst, were investigated in populations of two deciduous (Quercus robur L. and Quercus pubescens Willd.) and one evergreen (Quercus ilex L.) European oak. Mean cold hardiness values in January were -56, -45 and -27 degrees C for Q. robur, Q. pubescens and Q. ilex, respectively. Soluble carbohydrate concentrations were closely related to instantaneous cold hardiness, estimated by the electrolyte leakage method, whereas total carbohydrate concentration was related to maximum cold hardiness. Both cold hardiness and carbohydrate concentration showed a close linear relationship with temperatures at the location of the sampled population. Our results show that temporal variation in both the inter- and intraspecific cold hardiness in Europ...
Journal de gynécologie, obstétrique et biologie de la reproduction, 2014
To estimate the incidence, to describe the aetiology and to identify the risk factors of postpart... more To estimate the incidence, to describe the aetiology and to identify the risk factors of postpartum haemorrhage (PPH). Prospective study conducted in 106 French maternity units of six perinatal networks between December 2004 and November 2006. PPH was defined by a blood loss superior to 500 mL or necessitating an examination of the uterus, or a peripartum haemoglobin drop superior to 2 g/dL. Severe PPH was defined by at least one of these criteria : peripartum haemoglobin drop superior or equal to 4 g/dL, embolization, conservative surgical procedure, hysterectomy, transfusion, transfer to intensive care or death. The incidence of PPH was 6.4% [CI 95% 6.3-6.5] with variations between maternity units from 1.5% to 22.0%; incidence of severe PPH was 1.7% [CI 95% 1.6-1.8] with variations between units from 0% to 4%. Atony was the main aetiology of PPH, whatever the mode of delivery and severity. The risk factors identified were those classically described in the literature. In these six...
Journal de gynécologie, obstétrique et biologie de la reproduction, 2012
Describe management of severe postpartum haemorrhages (PPH) and its compliance with national guid... more Describe management of severe postpartum haemorrhages (PPH) and its compliance with national guidelines and identify determinants of non-optimal care. Population-based cohort study of 1379 women with severe PPH due to uterine atony after vaginal delivery, conducted in 106 French maternity units between December 2004 and November 2006. Severe PPH was defined by a peripartum haemoglobin drop of 4g/dL or more, blood loss of 1000 mL or more, hysterectomy, or transfer to intensive care for PPH. The frequency of each recommended procedure for the management of PPH was described. Associations between quality of care and both individual and institutional characteristics were assessed by univariate analysis and multivariate logistic regression. Management of severe PPH was not optimal in 65.9% of cases. The recommended components that were applied least often were administration of second line uterotonics, and transfusion of patients with a low haemoglobin. After adjustment for individual ch...
In this study, we analyze for the first time endoplasmic reticulum (ER) dynamics and organization... more In this study, we analyze for the first time endoplasmic reticulum (ER) dynamics and organization during oogenesis and embryonic divisions of Drosophila melanogaster using a Protein Disulfide Isomerase (PDI) GFP chimera protein. An accumulation of ER material into the oocyte takes place during the early steps of oogenesis. The compact organization of ER structures undergoes a transition to an expanded reticular network at fertilization. At the syncytial stage, this network connects to the nuclear envelope as each nucleus divides. Time-lapse confocal microscopy on PDI transgenic embryos allowed us to characterize a rapid redistribution of the ER during the mitotic phases. The ER network is massively recruited to the spindle poles in prophase. During metaphase most of the ER remains concentrated at the spindle poles and shortly thereafter forms several layers of membranes along the ruptured nuclear envelope. Later, during telophase an accumulation of ER material occurs at the spindle ...
The sympathetic, parasympathetic and enteric ganglia are the main components of the peripheral au... more The sympathetic, parasympathetic and enteric ganglia are the main components of the peripheral autonomic nervous system, and are all derived from the neural crest. The factors needed for these structures to develop include the transcription factor Mash1, the glial-derived neurotrophic factor GNDF and its receptor subunits, and the neuregulin signalling system, each of which is essential for the differentiation and survival of subsets of autonomic neurons. Here we show that all autonomic ganglia fail to form properly and degenerate in mice lacking the homeodomain transcription factor Phox2b, as do the three cranial sensory ganglia that are part of the autonomic reflex circuits. In the anlagen of the enteric nervous system and the sympathetic ganglia, Phox2b is needed for the expression of the GDNF-receptor subunit Ret and for maintaining Mash1 expression. Mutant ganglionic anlagen also fail to switch on the genes that encode two enzymes needed for the biosynthesis of the neurotransmi...
Recent evidence suggests that specific families of homeodomain transcription factors control the ... more Recent evidence suggests that specific families of homeodomain transcription factors control the generation and survival of distinct neuronal types. We had previously characterized the homeobox gene Phox2a, which is expressed in differentiating neurons of the central and peripheral autonomic nervous system as well as in motor nuclei of the hindbrain. Targeted deletion of the Phox2a gene affects part of the structures in which it is expressed: the locus coeruleus, visceral sensory and parasympathetic ganglia and, as we show here, the nuclei of the IIIrd and IVth cranial nerves. We now report on the characterization of Phox2b, a close relative of Phox2a, with an identical homeodomain. Phox2a and Phox2b are co-expressed at most sites, therefore suggesting a broader role for Phox2 genes in the specification of the autonomic nervous system and cranial motor nuclei than revealed by the Phox2a knock-out mice. A detailed analysis of the relative timing of Phox2a and Phox2b expression at various sites suggests positive cross-regulations, which are substantiated by the loss of Phox2b expression in cranial ganglia of Phox2a-deficient mice. In the major part of the rhombencephalon, Phox2b expression precedes that of Phox2a and starts in the proliferative neuroepithelium, in a pattern strikingly restricted on the dorsoventral axis and at rhombomeric borders. This suggests that Phox2b links early patterning events to the differentiation of defined neuronal populations in the hindbrain.
... X. Morin (xavier.morin@env.ethz.ch) and MJ Lechowicz, McGill Univ., Dept of Biology, 1205 Ave... more ... X. Morin (xavier.morin@env.ethz.ch) and MJ Lechowicz, McGill Univ., Dept of Biology, 1205 Avenue Dr. Penfield, Montréal, QC H3A ... The increasing availability of digital data on species distribution that can be analyzed using geographic informa-tion systems (Hawkins and Diniz ...
Journal de Gynécologie Obstétrique et Biologie de la Reproduction, 2013
To identify the defence mechanisms manifested by medical staff which could disturb the decision m... more To identify the defence mechanisms manifested by medical staff which could disturb the decision making, revealed by professionals of human science (PHS) in morbidity and mortality conferences (MMC). Application of two methods of psychological intervention in MMC, conducted between March 1st, 2009 and November 30, 2010, in 20 randomized maternity among five perinatal networks: the method of inter-active problem solving targeted at the functioning of the teams and the method for developing professional practice centred on individual. The data collection was realized during analyse of case in MMC, with note-taking by two pair PHS. The oral expressions of RMM' participant were secondarily re-written, analyzed and classed by theme. Fifty-four MMC were performed. The mechanisms of defence have been identified by PHS intervention in MMC: denial of situation, pact of denegation, rift and overprotection. They were be identified by two PHS intervention methods, this consolidates these results. This intervention began staff medical to transformation at different level, in particular to improve the capacity of cooperation. The identification of the mechanisms of defence in MMC enables staff medical to improve communication and quality relationship between healthcare professionals. This could constitute an actual factor of practices improvement. However, complementary studies must be performed to confirm this hypothesis.
ABSTRACT Background/Question/Methods Species distribution models are currently in wide use among ... more ABSTRACT Background/Question/Methods Species distribution models are currently in wide use among ecologists for projecting how species may respond to projected future climates with the intent, at least in some cases, to advise management on how to respond to the threat of climate change. Species distribution models may identify areas of future risk and security within a current range, as well as identify potential future habitat. Species distribution models, however, carry a large number of stringent assumptions. I examine assumptions in the light of a common suite of forest management actions in order to focus how ecologists might best frame tree distribution modeling to assist in managing for tree diversity under changing climates. Modeling issues examined include distinguishing fundamental and realized niches, the importance of biotic interactions, including disturbance; dispersal limitation; and adaptive capacity. Focal management actions I consider are fire management and planting, including planting species outside their current distributions (managed relocation). The focal study region that I assess is the Sierra Nevada range of California, where we have used an integrated team of scientists to assess forest vulnerability to climate change and fire. Results/Conclusions The assumptions of species distribution models virtually all have the potential to underestimate the potential of species to persist within their current distributions. Focusing on trees, the model assumption that a current occurrence reflects the capacity to recruit under the current climate is problematic in long-lived species such as trees. Differential climatic tolerances of seedlings versus adults, again may constraint the accuracy of distribution models to predict future outcomes. Species distribution models are likely to be considerably more robust in predicting potential future suitable habitat than they are at predicting range losses as a consequence of emerging climatic unsuitability. Further, biotic interactions can be a driver of population success, but modeling biotic interactions remains a challenge. Given the long life span of trees, management responses to habitat losses may manifest soonest in disturbance driven systems where fire can drive site type change. Other changes may be gradual and slow. In contrast, recruitment into new locations may be limited by dispersal. As a consequence, focusing modeling efforts on where, when and why range expansions should be fostered in trees is likely the best use of distribution modeling for climate change in trees.
Asymmetric localization is a prerequisite for inscuteable (insc) to function in coordinating and ... more Asymmetric localization is a prerequisite for inscuteable (insc) to function in coordinating and mediating asymmetric cell divisions in Drosophila. We show here that Partner of Inscuteable (Pins), a new component of asymmetric divisions, is required for Inscuteable to asymmetrically localize. In the absence of pins, Inscuteable becomes cytoplasmic and asymmetric divisions of neuroblasts and mitotic domain 9 cells show defects
We have investigated the specification of noradrenergic neurotransmitter identity in neural crest... more We have investigated the specification of noradrenergic neurotransmitter identity in neural crest stem cells (NCSCs). Retroviral expression of both wild-type and dominant-negative forms of the paired homeodomain transcription factor Phox2a indicates a crucial and direct role for this protein (and/or the closely related Phox2b) in the regulation of endogenous tyrosine hydroxylase (TH) and dopamine-β hydroxylase (DBH) gene expression in these
Although cold hardiness is known to be a major determinant of tree species distribution, its dyna... more Although cold hardiness is known to be a major determinant of tree species distribution, its dynamics and the factors that regulate it remain poorly understood. Variation in cold hardiness and carbohydrate concentration, from dormancy induction until bud burst, were investigated in populations of two deciduous (Quercus robur L. and Quercus pubescens Willd.) and one evergreen (Quercus ilex L.) European oak. Mean cold hardiness values in January were -56, -45 and -27 degrees C for Q. robur, Q. pubescens and Q. ilex, respectively. Soluble carbohydrate concentrations were closely related to instantaneous cold hardiness, estimated by the electrolyte leakage method, whereas total carbohydrate concentration was related to maximum cold hardiness. Both cold hardiness and carbohydrate concentration showed a close linear relationship with temperatures at the location of the sampled population. Our results show that temporal variation in both the inter- and intraspecific cold hardiness in Europ...
Journal de gynécologie, obstétrique et biologie de la reproduction, 2014
To estimate the incidence, to describe the aetiology and to identify the risk factors of postpart... more To estimate the incidence, to describe the aetiology and to identify the risk factors of postpartum haemorrhage (PPH). Prospective study conducted in 106 French maternity units of six perinatal networks between December 2004 and November 2006. PPH was defined by a blood loss superior to 500 mL or necessitating an examination of the uterus, or a peripartum haemoglobin drop superior to 2 g/dL. Severe PPH was defined by at least one of these criteria : peripartum haemoglobin drop superior or equal to 4 g/dL, embolization, conservative surgical procedure, hysterectomy, transfusion, transfer to intensive care or death. The incidence of PPH was 6.4% [CI 95% 6.3-6.5] with variations between maternity units from 1.5% to 22.0%; incidence of severe PPH was 1.7% [CI 95% 1.6-1.8] with variations between units from 0% to 4%. Atony was the main aetiology of PPH, whatever the mode of delivery and severity. The risk factors identified were those classically described in the literature. In these six...
Journal de gynécologie, obstétrique et biologie de la reproduction, 2012
Describe management of severe postpartum haemorrhages (PPH) and its compliance with national guid... more Describe management of severe postpartum haemorrhages (PPH) and its compliance with national guidelines and identify determinants of non-optimal care. Population-based cohort study of 1379 women with severe PPH due to uterine atony after vaginal delivery, conducted in 106 French maternity units between December 2004 and November 2006. Severe PPH was defined by a peripartum haemoglobin drop of 4g/dL or more, blood loss of 1000 mL or more, hysterectomy, or transfer to intensive care for PPH. The frequency of each recommended procedure for the management of PPH was described. Associations between quality of care and both individual and institutional characteristics were assessed by univariate analysis and multivariate logistic regression. Management of severe PPH was not optimal in 65.9% of cases. The recommended components that were applied least often were administration of second line uterotonics, and transfusion of patients with a low haemoglobin. After adjustment for individual ch...
In this study, we analyze for the first time endoplasmic reticulum (ER) dynamics and organization... more In this study, we analyze for the first time endoplasmic reticulum (ER) dynamics and organization during oogenesis and embryonic divisions of Drosophila melanogaster using a Protein Disulfide Isomerase (PDI) GFP chimera protein. An accumulation of ER material into the oocyte takes place during the early steps of oogenesis. The compact organization of ER structures undergoes a transition to an expanded reticular network at fertilization. At the syncytial stage, this network connects to the nuclear envelope as each nucleus divides. Time-lapse confocal microscopy on PDI transgenic embryos allowed us to characterize a rapid redistribution of the ER during the mitotic phases. The ER network is massively recruited to the spindle poles in prophase. During metaphase most of the ER remains concentrated at the spindle poles and shortly thereafter forms several layers of membranes along the ruptured nuclear envelope. Later, during telophase an accumulation of ER material occurs at the spindle ...
The sympathetic, parasympathetic and enteric ganglia are the main components of the peripheral au... more The sympathetic, parasympathetic and enteric ganglia are the main components of the peripheral autonomic nervous system, and are all derived from the neural crest. The factors needed for these structures to develop include the transcription factor Mash1, the glial-derived neurotrophic factor GNDF and its receptor subunits, and the neuregulin signalling system, each of which is essential for the differentiation and survival of subsets of autonomic neurons. Here we show that all autonomic ganglia fail to form properly and degenerate in mice lacking the homeodomain transcription factor Phox2b, as do the three cranial sensory ganglia that are part of the autonomic reflex circuits. In the anlagen of the enteric nervous system and the sympathetic ganglia, Phox2b is needed for the expression of the GDNF-receptor subunit Ret and for maintaining Mash1 expression. Mutant ganglionic anlagen also fail to switch on the genes that encode two enzymes needed for the biosynthesis of the neurotransmi...
Recent evidence suggests that specific families of homeodomain transcription factors control the ... more Recent evidence suggests that specific families of homeodomain transcription factors control the generation and survival of distinct neuronal types. We had previously characterized the homeobox gene Phox2a, which is expressed in differentiating neurons of the central and peripheral autonomic nervous system as well as in motor nuclei of the hindbrain. Targeted deletion of the Phox2a gene affects part of the structures in which it is expressed: the locus coeruleus, visceral sensory and parasympathetic ganglia and, as we show here, the nuclei of the IIIrd and IVth cranial nerves. We now report on the characterization of Phox2b, a close relative of Phox2a, with an identical homeodomain. Phox2a and Phox2b are co-expressed at most sites, therefore suggesting a broader role for Phox2 genes in the specification of the autonomic nervous system and cranial motor nuclei than revealed by the Phox2a knock-out mice. A detailed analysis of the relative timing of Phox2a and Phox2b expression at various sites suggests positive cross-regulations, which are substantiated by the loss of Phox2b expression in cranial ganglia of Phox2a-deficient mice. In the major part of the rhombencephalon, Phox2b expression precedes that of Phox2a and starts in the proliferative neuroepithelium, in a pattern strikingly restricted on the dorsoventral axis and at rhombomeric borders. This suggests that Phox2b links early patterning events to the differentiation of defined neuronal populations in the hindbrain.
... X. Morin (xavier.morin@env.ethz.ch) and MJ Lechowicz, McGill Univ., Dept of Biology, 1205 Ave... more ... X. Morin (xavier.morin@env.ethz.ch) and MJ Lechowicz, McGill Univ., Dept of Biology, 1205 Avenue Dr. Penfield, Montréal, QC H3A ... The increasing availability of digital data on species distribution that can be analyzed using geographic informa-tion systems (Hawkins and Diniz ...
Journal de Gynécologie Obstétrique et Biologie de la Reproduction, 2013
To identify the defence mechanisms manifested by medical staff which could disturb the decision m... more To identify the defence mechanisms manifested by medical staff which could disturb the decision making, revealed by professionals of human science (PHS) in morbidity and mortality conferences (MMC). Application of two methods of psychological intervention in MMC, conducted between March 1st, 2009 and November 30, 2010, in 20 randomized maternity among five perinatal networks: the method of inter-active problem solving targeted at the functioning of the teams and the method for developing professional practice centred on individual. The data collection was realized during analyse of case in MMC, with note-taking by two pair PHS. The oral expressions of RMM' participant were secondarily re-written, analyzed and classed by theme. Fifty-four MMC were performed. The mechanisms of defence have been identified by PHS intervention in MMC: denial of situation, pact of denegation, rift and overprotection. They were be identified by two PHS intervention methods, this consolidates these results. This intervention began staff medical to transformation at different level, in particular to improve the capacity of cooperation. The identification of the mechanisms of defence in MMC enables staff medical to improve communication and quality relationship between healthcare professionals. This could constitute an actual factor of practices improvement. However, complementary studies must be performed to confirm this hypothesis.
ABSTRACT Background/Question/Methods Species distribution models are currently in wide use among ... more ABSTRACT Background/Question/Methods Species distribution models are currently in wide use among ecologists for projecting how species may respond to projected future climates with the intent, at least in some cases, to advise management on how to respond to the threat of climate change. Species distribution models may identify areas of future risk and security within a current range, as well as identify potential future habitat. Species distribution models, however, carry a large number of stringent assumptions. I examine assumptions in the light of a common suite of forest management actions in order to focus how ecologists might best frame tree distribution modeling to assist in managing for tree diversity under changing climates. Modeling issues examined include distinguishing fundamental and realized niches, the importance of biotic interactions, including disturbance; dispersal limitation; and adaptive capacity. Focal management actions I consider are fire management and planting, including planting species outside their current distributions (managed relocation). The focal study region that I assess is the Sierra Nevada range of California, where we have used an integrated team of scientists to assess forest vulnerability to climate change and fire. Results/Conclusions The assumptions of species distribution models virtually all have the potential to underestimate the potential of species to persist within their current distributions. Focusing on trees, the model assumption that a current occurrence reflects the capacity to recruit under the current climate is problematic in long-lived species such as trees. Differential climatic tolerances of seedlings versus adults, again may constraint the accuracy of distribution models to predict future outcomes. Species distribution models are likely to be considerably more robust in predicting potential future suitable habitat than they are at predicting range losses as a consequence of emerging climatic unsuitability. Further, biotic interactions can be a driver of population success, but modeling biotic interactions remains a challenge. Given the long life span of trees, management responses to habitat losses may manifest soonest in disturbance driven systems where fire can drive site type change. Other changes may be gradual and slow. In contrast, recruitment into new locations may be limited by dispersal. As a consequence, focusing modeling efforts on where, when and why range expansions should be fostered in trees is likely the best use of distribution modeling for climate change in trees.
Asymmetric localization is a prerequisite for inscuteable (insc) to function in coordinating and ... more Asymmetric localization is a prerequisite for inscuteable (insc) to function in coordinating and mediating asymmetric cell divisions in Drosophila. We show here that Partner of Inscuteable (Pins), a new component of asymmetric divisions, is required for Inscuteable to asymmetrically localize. In the absence of pins, Inscuteable becomes cytoplasmic and asymmetric divisions of neuroblasts and mitotic domain 9 cells show defects
We have investigated the specification of noradrenergic neurotransmitter identity in neural crest... more We have investigated the specification of noradrenergic neurotransmitter identity in neural crest stem cells (NCSCs). Retroviral expression of both wild-type and dominant-negative forms of the paired homeodomain transcription factor Phox2a indicates a crucial and direct role for this protein (and/or the closely related Phox2b) in the regulation of endogenous tyrosine hydroxylase (TH) and dopamine-β hydroxylase (DBH) gene expression in these
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