883 resultados para Sufficient Condition


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Melanin is the most common pigment in animal integuments and is responsible for some of the most striking ornaments. A central tenet of sexual selection theory states that melanin-based traits can signal absolute individual quality in any environment only if their expression is condition-dependent. Significant costs imposed by an ornament would ensure that only the highest quality individuals display the most exaggerated forms of the signal. Firm evidence that melanin-based traits can be condition-dependent is still rare in birds. In an experimental test of this central assumption, we report condition-dependent expression of a melanin-based trait in the Eurasian kestrel (Falco tinnunculus). We manipulated nestling body condition by reducing or increasing the number of nestlings soon after hatching. A few days before fledging, we measured the width of sub-terminal black bands on the tail feathers. Compared to nestlings from enlarged broods, individuals raised in reduced broods were in better condition and thereby developed larger sub-terminal bands. Furthermore, in 2 years, first-born nestlings also developed larger sub-terminal bands than their younger siblings that are in poorer condition. This demonstrates that expression of melanin-based traits can be condition-dependent.

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A 6N-dimensional alternative formulation is proposed for constrained Hamiltonian systems. In this context the noninteraction theorem is derived from the world-line conditions. A model of two interacting particles is exhibited where physical coordinates are canonical.

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In mammals, the presence of excitable cells in muscles, heart and nervous system is crucial and allows fast conduction of numerous biological information over long distances through the generation of action potentials (AP). Voltage-gated sodium channels (Navs) are key players in the generation and propagation of AP as they are responsible for the rising phase of the AP. Navs are heteromeric proteins composed of a large pore-forming a-subunit (Nav) and smaller ß-auxiliary subunits. There are ten genes encoding for Navl.l to Nav1.9 and NaX channels, each possessing its own specific biophysical properties. The excitable cells express differential combinations of Navs isoforms, generating a distinct electrophysiological signature. Noteworthy, only when anchored at the membrane are Navs functional and are participating in sodium conductance. In addition to the intrinsic properties of Navs, numerous regulatory proteins influence the sodium current. Some proteins will enhance stabilization of membrane Navs while others will favour internalization. Maintaining equilibrium between the two is of crucial importance for controlling cellular excitability. The E3 ubiquitin ligase Nedd4-2 is a well-characterized enzyme that negatively regulates the turnover of many membrane proteins including Navs. On the other hand, ß-subunits are known since long to stabilize Navs membrane anchoring. Peripheral neuropathic pain is a disabling condition resulting from nerve injury. It is characterized by the dysregulation of Navs expressed in dorsal root ganglion (DRG) sensory neurons as highlighted in different animal models of neuropathic pain. Among Navs, Nav1.7 and Nav1.8 are abundantly and specifically expressed in DRG sensory neurons and have been recurrently incriminated in nociception and neuropathic pain development. Using the spared nerve injury (SNI) experimental model of neuropathic pain in mice, I observed a specific reduction of Nedd4-2 in DRG sensory neurons. This decrease subsequently led to an upregulation of Nav1.7 and Nav1.8 protein and current, in the axon and the DRG neurons, respectively, and was sufficient to generate neuropathic pain-associated hyperexcitability. Knocking out Nedd4-2 specifically in nociceptive neurons led to the same increase of Nav1.7 and Nav1.8 concomitantly with an increased thermal sensitivity in mice. Conversely, rescuing Nedd4-2 downregulation using viral vector transfer attenuated neuropathic pain mechanical hypersensitivity. This study demonstrates the significant role of Nedd4-2 in regulating cellular excitability in vivo and its involvement in neuropathic pain development. The role of ß-subunits in neuropathic pain was already demonstrated in our research group. Because of their stabilization role, the increase of ßl, ß2 and ß3 subunits in DRGs after SNI led to increased Navs anchored at the membrane. Here, I report a novel mechanism of regulation of a-subunits by ß- subunits in vitro; ßl and ß3-subunits modulate the glycosylation pattern of Nav1.7, which might account for stabilization of its membrane expression. This opens new perspectives for investigation Navs state of glycosylation in ß-subunits dependent diseases, such as in neuropathic pain. - Chez les mammifères, la présence de cellules excitables dans les muscles, le coeur et le système nerveux est cruciale; elle permet la conduction rapide de nombreuses informations sur de longues distances grâce à la génération de potentiels d'action (PA). Les canaux sodiques voltage-dépendants (Navs) sont des participants importants dans la génération et la propagation des PA car ils sont responsables de la phase initiale de dépolarisation du PA. Les Navs sont des protéines hétéromériques composées d'une grande sous-unité a (formant le pore du canal) et de petites sous-unités ß accompagnatrices. Il existe dix gènes qui codent pour les canaux sodiques, du Nav 1.1 au Nav 1.9 ainsi que NaX, chacun possédant des propriétés biophysiques spécifiques. Les cellules excitables expriment différentes combinaisons des différents isoformes de Navs, qui engendrent une signature électrophysiologique distincte. Les Navs ne sont fonctionnels et ne participent à la conductibilité du Na+, que s'ils sont ancrés à la membrane plasmique. En plus des propriétés intrinsèques des Navs, de nombreuses protéines régulatrices influencent également le courant sodique. Certaines protéines vont favoriser l'ancrage et la stabilisation des Navs exprimés à la membrane, alors que d'autres vont plutôt favoriser leur internalisation. Maintenir l'équilibre des deux processus est crucial pour contrôler l'excitabilité cellulaire. Dans ce contexte, Nedd4-2, de la famille des E3 ubiquitin ligase, est une enzyme bien caractérisée qui régule l'internalisation de nombreuses protéines, notamment celle des Navs. Inversement, les sous-unités ß sont connues depuis longtemps pour stabiliser l'ancrage des Navs à la membrane. La douleur neuropathique périphérique est une condition débilitante résultant d'une atteinte à un nerf. Elle est caractérisée par la dérégulation des Navs exprimés dans les neurones sensoriels du ganglion spinal (DRG). Ceci a été démontré à de multiples occasions dans divers modèles animaux de douleur neuropathique. Parmi les Navs, Nav1.7 et Nav1.8 sont abondamment et spécifiquement exprimés dans les neurones sensoriels des DRG et ont été impliqués de façon récurrente dans le développement de la douleur neuropathique. En utilisant le modèle animal de douleur neuropathique d'épargne du nerf sural (spared nerve injury, SNI) chez la souris, j'ai observé une réduction spécifique des Nedd4-2 dans les neurones sensoriels du DRG. Cette diminution avait pour conséquence l'augmentation de l'expression des protéines et des courants de Nav 1.7 et Nav 1.8, respectivement dans l'axone et les neurones du DRG, et était donc suffisante pour créer l'hyperexcitabilité associée à la douleur neuropathique. L'invalidation pour le gène codant pour Nedd4-2 dans une lignée de souris génétiquement modifiées a conduit à de similaires augmentations de Nav1.7 et Nav1.8, parallèlement à une augmentation à la sensibilité thermique. A l'opposé, rétablir une expression normale de Nedd4-2 en utilisant un vecteur viral a eu pour effet de contrecarrer le développement de l'hypersensibilité mécanique lié à ce modèle de douleur neuropathique. Cette étude démontre le rôle important de Nedd4-2 dans la régulation de l'excitabilité cellulaire in vivo et son implication dans le développement des douleurs neuropathiques. Le rôle des sous-unités ß dans les douleurs neuropathiques a déjà été démontré dans notre groupe de recherche. A cause de leur rôle stabilisateur, l'augmentation des sous-unités ßl, ß2 et ß3 dans les DRG après SNI, conduit à une augmentation des Navs ancrés à la membrane. Dans mon travail de thèse, j'ai observé un nouveau mécanisme de régulation des sous-unités a par les sous-unités ß in vitro. Les sous-unités ßl et ß3 régulent l'état de glycosylation du canal Nav1.7, et stabilisent son expression membranaire. Ceci ouvre de nouvelles perspectives dans l'investigation de l'état de glycosylation des Navs dans des maladies impliquant les sous-unités ß, notamment les douleurs neuropathiques.

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The hypothesis of this study was that the absence of soil tillage in long-term no-tillage (NT) systems can be detrimental to soil aeration. The objective was to assess the aeration condition of an Oxisol (Rhodic Ferrasol), very clayey texture (750 g kg-1 of clay; 200 g kg-1 of sand), after 30 years of cultivation under NT. The physical property soil air permeability (Ka) is sensitive to changes in the soil pore system. Aside from Ka, the air-filled porosity (ε a) and indices of pore continuity (K1 and N), derived from the relationship between Ka and εa, were used as indices of soil aeration. From the soil layers 0.0-0.1 and 0.1-0.2 m, 240 undisturbed samples were collected along a transect perpendicular to the crop rows, at three sampling positions: corn plant row (CR); center of the interrow (INT); and the equidistant point between CR and INT (PE). The properties Ka and εa were determined at soil matric potentials (Ψm) of -2, -4, -6, -10, -30, and -50 kPa. Soil bulk density (BD) was also determined. The results confirmed the hypothesis. In the 0.0-0.1 m layer, Ka, K1, N and Ψa were significantly greater and BD significantly lower in CR than at the other sampling positions. At a Ψm of -10 kPa, the Ka of CR was 6.9 and 8.4 times higher than in PE and INT, respectively, in the 0.0-0.1 m layer. The properties Ka, K1 and N were sensitive enough to detect changes in the pore system and their differences between the sampling positions demonstrated the importance of the spatial location for soil sampling. Tilling the crop rows provides better soil aeration under NT.

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The Annual Condition of Education Report includes an expanded Background Demographics section. This section contains information on population, economic, and social data, providing a comparison between Iowa, other states, and the Nation. Geographic Information System (GIS) maps are presented to allow the reader to easily compare between two or more geographies. In some instances, trends are also reported. Information displayed in this section was obtained from a variety of sources and is noted on each table or figure. In all areas, the most recent data available were used.

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The Annual Condition of Education Report includes an expanded Background Demographics section. This section contains information on population, economic, and social data, providing a comparison between Iowa, other states, and the Nation. Geographic Information System (GIS) maps are presented to allow the reader to easily compare between two or more geographies. In some instances, trends are also reported. Information displayed in this section was obtained from a variety of sources and is noted on each table or figure. In all areas, the most recent data available were used.

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The relationship between sperm velocity and individual age, size, body condition and fluctuating asymmetry was investigated in Alpine whitefish Coregonus fatioi. The fish analysed belonged to one among several sympatric whitefish populations of Lake Thun, Switzerland, which are characterized by a high prevalence of gonad alterations. Therefore, sperm velocity data were also tested for a link between gonad deformation and sperm swimming speed. Sperm velocity was significantly lower in larger-grown individuals and in individuals of higher body condition. As expected, sperm velocity was higher in males with higher levels of fluctuating asymmetry, but it did not significantly vary with male age. Moreover, variation in sperm velocity was found to be significantly higher in individuals showing some types of gonad alterations but it did not significantly correlate with the presence of other types of alterations. (C) 2007 The Authors Journal compilation (C) 2007 The Fisheries Society of the British Isles.

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A transcript of the Condition of the State of Iowa speech by Governor Terry Branstad delivered at the State Capitol on January 14, 2013

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The Iowa Department of Education collects data on fiscal year credit enrollment, non-credit enrollment, economic development programs, and institutional data (i.e., faculty information, tuition). This report summarizes several aspects of the data.

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The Annual Condition of Education Report includes an expanded Background Demographics section. This section contains information on population, economic, and social data, providing a comparison between Iowa, other states, and the Nation. Geographic Information System (GIS) maps are presented to allow the reader to easily compare between two or more geographies. In some instances, trends are also reported. Information displayed in this section was obtained from a variety of sources and is noted on each table or figure. In all areas, the most recent data available were used.

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In contrast to intact BALB/c mice, BALB/c mice rendered deficient in Vbeta4+ CD4+ T cells develop a Th1 response to infection with Leishmania major and are resistant. Vbeta4-deficient BALB/c mice are unable to generate the early IL-4 transcription occurring in Vbeta4 Valpha8 CD4+ T cells of BALB/c mice within 1 day of infection. Here we demonstrate that treatment of Vbeta4-deficient BALB/c mice with IL-4 during the first 64 h after infection instructs Th2 cell development and susceptibility to infection. The demonstrated inability of IL-4 to reverse the resistant phenotype of BALB/c mice treated with anti-CD4 mAb the day before infection suggest that these effects of IL-4 require its interaction with CD4+ T cells. In contrast to draining lymph node cells from BALB/c mice, cells from Vbeta4-deficient BALB/c mice remain responsive to IL-12 following infection. Strikingly, administration of IL-4 to Vbeta4-deficient BALB/c mice renders their lymph node cells unresponsive to IL-12 by down-regulating IL-12R beta2-chain expression. This study directly demonstrates that in BALB/c mice IL-4 is necessary and sufficient to initiate the molecular events steering Th2 cell maturation and susceptibility to L. major.

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BACKGROUND: Hypercalcaemia has been shown to occur in about 20% of patients with major burns requiring prolonged intensive care unit (ICU) treatment, and it may be associated with renal failure. Having observed the early onset of hypercalcaemia, the study aimed to determine the frequency and timing of this condition in a European patient cohort. METHODS: A retrospective cohort study on a prospectively collected, computerised database of the 225 burn-injury ICU admissions between 2001 and 2007 was undertaken. The inclusion criteria included: burns >20% of the body surface area (BSA) or in-hospital stay >20 days. Hypercalcaemia was defined as an ionised plasma calcium (Ca(2+)) concentration >1.32 mmol l(-1) (or total corrected calcium=[Ca]c>2.55 mmol l(-1)). Four emblematic cases are reported in this article. RESULTS: A total of 73 patients met the inclusion criteria (age: 13-88 years, burns: 12-85% BSA): of these, 22 (30%) developed hypercalcaemia. The median time to the first hypercalcaemia value was 21 days. Only 11 patients had both high Ca(2+) and elevated [Ca]c (which remained normal in others). The risk factors of the disorder were burned surface (p=0.017) and immobilisation (fluidised bed use: p<0.05, duration: p=0.02) followed by burned BSA. Acute renal failure tended to be more frequent in hypercalcaemic patients (five (23%) vs. three (6%): p=0.11), while mortality was not increased. The disorder resolved with hydration and mobilisation in most cases: pamidronate was successful in three cases that were most severe. CONCLUSION: Hypercalcaemia and associated acute renal failure occur more frequently and earlier than previously reported. Determining the ionised Ca rather than the total Ca with albumin correction enables earlier detection of hypercalcaemia. Bisphosphonates are an effective treatment option in controlling severe hypercalcaemia and preventing bone loss.

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Precast prestressed concrete panels have been used as subdecks in bridge construction in Iowa and other states. To investigate the performance of these types of composite slabs at locations adjacent to abutment and pier diaphragms in skewed bridges, a research prcject which involved surveys of design agencies and precast producers, field inspections of existing bridges, analytical studies, and experimental testing was conducted. The survey results from the design agencies and panel producers showed that standardization of precast panel construction would be desirable, that additional inspections at the precast plant and at the bridge site would be beneficial, and that some form of economical study should be undertaken to determine actual cost savings associated with composite slab construction. Three bridges in Hardin County, Iowa were inspected to observe general geometric relationships, construction details, and to note the visual condition of the bridges. Hairline cracks beneath several of the prestressing strands in many of the precast panels were observed, and a slight discoloration of the concrete was seen beneath most of the strands. Also, some rust staining was visible at isolated locations on several panels. Based on the findings of these inspections, future inspections are recommended to monitor the condition of these and other bridges constructed with precast panel subdecks. Five full-scale composite slab specimens were constructed in the Structural Engineering Laboratory at Iowa State University. One specimen modeled bridge deck conditions which are not adjacent to abutment or pier diaphragms, and the other four specimens represented the geometric conditions which occur for skewed diaphragms of 0, 15, 30, and 40 degrees. The specimens were subjected to wheel loads of service and factored level magnitudes at many locations on the slab surface and to concentrated loads which produced failure of the composite slab. The measured slab deflections and bending strains at both service and factored load levels compared reasonably well with the results predicted by simplified Finite element analyses of the specimens. To analytically evaluate the nominal strength for a composite slab specimen, yield-line and punching shear theories were applied. Yield-line limit loads were computed using the crack patterns generated during an ultimate strength test. In most cases, these analyses indicated that the failure mode was not flexural. Since the punching shear limit loads in most instances were close to the failure loads, and since the failure surfaces immediately adjacent to the wheel load footprint appeared to be a truncated prism shape, the probable failure mode for all of the specimens was punching shear. The development lengths for the prestressing strands in the rectangular and trapezoidal shaped panels was qualitatively investigated by monitoring strand slippage at the ends of selected prestressing strands. The initial strand transfer length was established experimentally by monitoring concrete strains during strand detensioning, and this length was verified analytically by a finite element analysis. Even though the computed strand embedment lengths in the panels were not sufficient to fully develop the ultimate strand stress, sufficient stab strength existed. Composite behavior for the slab specimens was evaluated by monitoring slippage between a panel and the topping slab and by computation of the difference in the flexural strains between the top of the precast panel and the underside of the topping slab at various locations. Prior to the failure of a composite slab specimen, a localized loss of composite behavior was detected. The static load strength performance of the composite slab specimens significantly exceeded the design load requirements. Even with skew angles of up to 40 degrees, the nominal strength of the slabs did not appear to be affected when the ultimate strength test load was positioned on the portion of each slab containing the trapezoidal-shaped panel. At service and factored level loads, the joint between precast panels did not appear to influence the load distribution along the length of the specimens. Based on the static load strength of the composite slab specimens, the continued use of precast panels as subdecks in bridge deck construction is recommended.