Effet de la température sur l'installation et la croissance des plantes annuelles de marais temporaires méditerranéens

L'abondance des plantes annuelles des marais temporaires est soumise à de fortes fluctuations dans le temps. Celles-ci peuvent être dues à la variabilité du climat méditerranéen. Nous avons étudié expérimentalement la relation entre ces variations d'abondance et la température de l'eau. La phase d'installation et la phase de croissance des espèces ont été étudiées dans trois gammes de températures. Chaque espèce possède son propre patron de germination, lequel varie avec la température. La vitesse d'émergence des plantules de toutes les espèces change en relation avec la température. Le taux de germination n'est modifié significativement que pour les charophytes, avec une forte diminution en conditions froides. L'abondance des réserves de semences de #Chara sp. et de #Zannichellia spp. explique en grande partie leur dynamique de germination. Le recouvrement à la fin de la phase d'installation est maximal en conditions chaudes et le #Callitriche truncata et les #Zannichellia spp. présentent plus fortes valeurs. En fin de période de croissance, le #Ranunculus baudotii domine généralement la communauté en terme de biomasse tandis que le #C. truncata est dominé. La biomasse des espèces est modifiée par la température de la phase d'installation et (ou) de croissance, sauf pour les #Zannichellia$ spp. Il n'existe pas d'effet de "préemption" apparent : les stratégies de vie contrastées des espèces aboutissent à modifier les relations de dominance au cours du cycle de vie. (Résumé d'auteur

GALNT2 as a novel modulator of adipogenesis and adipocyte insulin signaling

Background/objectives: A better understanding of adipose tissue biology is crucial to tackle insulin resistance and eventually coronary heart disease and diabetes, leading causes of morbidity and mortality worldwide. GALNT2, a GalNAc-transferase, positively modulates insulin signaling in human liver cells by down-regulating ENPP1, an insulin signaling inhibitor. GALNT2 expression is increased in adipose tissue of obese as compared to that of non-obese individuals. Whether this association is secondary to a GALNT2-insulin sensitizing effect exerted also in adipocytes is unknown. We then investigated in mouse 3T3-L1 adipocytes the GALNT2 effect on adipogenesis, insulin signaling and expression levels of both Enpp1 and 72 adipogenesis-related genes. Methods: Stable over-expressing GALNT2 and GFP preadipocytes (T 0 ) were generated. Adipogenesis was induced with (R+) or without (R−) rosiglitazone and investigated after 15 days (T 15 ). Lipid accumulation (by Oil Red-O staining) and intracellular triglycerides (by fluorimetric assay) were measured. Lipid droplets (LD) measures were analyzed at confocal microscope. Gene expression was assessed by RT-PCR and insulin-induced insulin receptor (IR), IRS1, JNK and AKT phosphorylation by Western blot. Results: Lipid accumulation, triglycerides and LD measures progressively increased from T 0 to T 15 R- and furthermore to T 15 R+. Such increases were significantly higher in GALNT2 than in GFP cells so that, as compared to T 15 R+GFP, T 15 R- GALNT2 cells showed similar (intracellular lipid and triglycerides accumulation) or even higher (LD measures, p < 0.01) values. In GALNT2 preadipocytes, insulin-induced IR, IRS1 and AKT activation was higher than that in GFP cells. GALNT2 effect was totally abolished during adipocyte maturation and completely reversed at late stage maturation. Such GALNT2 effect trajectory was paralleled by coordinated changes in the expression of Enpp1 and adipocyte-maturation key genes. Conclusions: GALNT2 is a novel modulator of adipogenesis and related cellular phenotypes, thus becoming a potential target for tackling the obesity epidemics and its devastating sequelae

Autism Spectrum Disorder and the Child\u27s Weight–Related Behaviors: A Parents\u27 Perspective

Purpose To explore parent perspectives of how the attributes of their child\u27s autism spectrum disorder(ASD) impact nutrition, physical activity, screen time behaviors and risk for obesity. Secondarily, we examined the parent\u27s perception of the healthcare providers (HCP) influence on these weight-related behaviors. Design and method We conducted and audio-recorded telephone interviews with parents of children with ASD (n = 8) using a structured question guide. Data were transcribed and thematic analysis was conducted. Issues surrounding weight-related behaviors and parental strategies used were reported. Results Two overarching themes with eight subthemes emerged: (1) Challenges related to features of ASD (subthemes included fixation on food, sensory issues/rigidity, developmental factors, impaired social skills, and medication effects) and (2) Challenges related to the care of children with ASD (subthemes included lack of individualized care planning, picking your battles and the impact of ASD on family). Conclusion Strategies extracted from the parent narratives promoted both healthy and unhealthy weight-related behaviors. The key finding in this study is that some parents did not follow HCP guidance when they perceived that the HCP did not understand their particular situation. Practice Implications Implementation of healthy weight-related behaviors can be optimized when providers consider the child\u27s challenging ASD behaviors, affirm the difficulties encountered by the family and provide guidance that builds on the individual child/family strengths

Q2Q_2-free families in the Boolean lattice

For a family $\mathcal{F}$ of subsets of [n]=\{1, 2, ..., n} ordered by inclusion, and a partially ordered set P, we say that $\mathcal{F}$ is P-free if it does not contain a subposet isomorphic to P. Let $ex(n, P)$ be the largest size of a P-free family of subsets of [n]. Let $Q_2$ be the poset with distinct elements a, b, c, d, a<b, c<d; i.e., the 2-dimensional Boolean lattice. We show that $2N -o(N) \leq ex(n, Q_2)\leq 2.283261N +o(N),$ where $N = \binom{n}{\lfloor n/2 \rfloor}$. We also prove that the largest $Q_2$-free family of subsets of [n] having at most three different sizes has at most 2.20711N members.Comment: 18 pages, 2 figure

Superselectors: Efficient Constructions and Applications

We introduce a new combinatorial structure: the superselector. We show that superselectors subsume several important combinatorial structures used in the past few years to solve problems in group testing, compressed sensing, multi-channel conflict resolution and data security. We prove close upper and lower bounds on the size of superselectors and we provide efficient algorithms for their constructions. Albeit our bounds are very general, when they are instantiated on the combinatorial structures that are particular cases of superselectors (e.g., (p,k,n)-selectors, (d,\ell)-list-disjunct matrices, MUT_k(r)-families, FUT(k, a)-families, etc.) they match the best known bounds in terms of size of the structures (the relevant parameter in the applications). For appropriate values of parameters, our results also provide the first efficient deterministic algorithms for the construction of such structures

Ultrasensitive Displacement Noise Measurement of Carbon Nanotube Mechanical Resonators

Mechanical resonators based on a single carbon nanotube are exceptional sensors of mass and force. The force sensitivity in these ultra-light resonators is often limited by the noise in the detection of the vibrations. Here, we report on an ultra-sensitive scheme based on a RLC resonator and a low-temperature amplifier to detect nanotube vibrations. We also show a new fabrication process of electromechanical nanotube resonators to reduce the separation between the suspended nanotube and the gate electrode down to $\sim 150$~nm. These advances in detection and fabrication allow us to reach $0.5~\mathrm{pm}/\sqrt{\mathrm{Hz}}$ displacement sensitivity. Thermal vibrations cooled cryogenically at 300~mK are detected with a signal-to-noise ratio as high as 17~dB. We demonstrate $4.3~\mathrm{zN}/\sqrt{\mathrm{Hz}}$ force sensitivity, which is the best force sensitivity achieved thus far with a mechanical resonator. Our work is an important step towards imaging individual nuclear spins and studying the coupling between mechanical vibrations and electrons in different quantum electron transport regimes.Comment: 9 pages, 5 figure

Management of struvite uroliths in dogs.

Urolithiasis is a common clinical problem in dogs. Struvite and calcium oxalate are the predominant mineral types in dog urolithiasis. The aim of the present study was to compare the effect of two commercial dry foods formulated for the management of struvite urolithiasis with different anion–cation balance on urinary pH. For the trial, twelve privately owned adult dogs showing struvite urolithiasis were studied. The dogs were randomly divided into two groups (A and B) and fed two dissolving diets for 3 months. The analyses of urine were repeated six times. In both diets, the anion–cation balance was negative ( − 203 and − 192 for diets A and B, respectively). At the first urine analysis, pH values of all the dogs were close to 8·0, and bacteria were present in about 70 % of the samples and thus an antimicrobial was administered for 1 week. Both groups showed a progressive decrease in pH values, and after 2 months, in both cases, the recommended pH values for stone dissolution were achieved. From the sampling at 30 d, group A showed pH values significantly (P &lt; 0·05) lower than group B, probably due to the lower anion–cation balance of diet A. The combination of antimicrobial and dietary therapy allowed the dissolution of struvite uroliths in both groups, even if the utilisation of the diet characterised by the lower anion–cation balance seems to decrease the urinary pH more rapidly. In this case, it seems necessary to interrupt the dietary treatment in order to avoid the risk of other diseases.</jats:p

A Role for the Kolliker-Fuse Nucleus in Cholinergic Modulation of Breathing at Night During Wakefulness and NREM Sleep

For many years, acetylcholine has been known to contribute to the control of breathing and sleep. To probe further the contributions of cholinergic rostral pontine systems in control of breathing, we designed this study to test the hypothesis that microdialysis (MD) of the muscarinic receptor antagonist atropine into the pontine respiratory group (PRG) would decrease breathing more in animals while awake than while in NREM sleep. In 16 goats, cannulas were bilaterally implanted into rostral pontine tegmental nuclei (n = 3), the lateral (n = 3) or medial (n = 4) parabrachial nuclei, or the Kölliker-Fuse nucleus (KFN; n = 6). After \u3e2 wk of recovery from surgery, the goats were studied during a 45-min period of MD with mock cerebrospinal fluid (mCSF), followed by at least 30 min of recovery and a second 45-min period of MD with atropine. Unilateral and bilateral MD studies were completed during the day and at night. MD of atropine into the KFN at night decreased pulmonary ventilation and breathing frequency and increased inspiratory and expiratory time by 12–14% during both wakefulness and NREM sleep. However, during daytime studies, MD of atropine into the KFN had no effect on these variables. Unilateral and bilateral nighttime MD of atropine into the KFN increased levels of NREM sleep by 63 and 365%, respectively. MD during the day or at night into the other three pontine sites had minimal effects on any variable studied. Finally, compared with MD of mCSF, bilateral MD of atropine decreased levels of acetylcholine and choline in the effluent dialysis fluid. Our data support the concept that the KFN is a significant contributor to cholinergically modulated control of breathing and sleep

Thin walled pottery from Alife (Northern Campania, Italy)

The file attached is the published version of the article

Noise-Resilient Group Testing: Limitations and Constructions

We study combinatorial group testing schemes for learning $d$-sparse Boolean vectors using highly unreliable disjunctive measurements. We consider an adversarial noise model that only limits the number of false observations, and show that any noise-resilient scheme in this model can only approximately reconstruct the sparse vector. On the positive side, we take this barrier to our advantage and show that approximate reconstruction (within a satisfactory degree of approximation) allows us to break the information theoretic lower bound of $\tilde{\Omega}(d^2 \log n)$ that is known for exact reconstruction of $d$-sparse vectors of length $n$ via non-adaptive measurements, by a multiplicative factor $\tilde{\Omega}(d)$. Specifically, we give simple randomized constructions of non-adaptive measurement schemes, with $m=O(d \log n)$ measurements, that allow efficient reconstruction of $d$-sparse vectors up to $O(d)$ false positives even in the presence of $\delta m$ false positives and $O(m/d)$ false negatives within the measurement outcomes, for any constant $\delta < 1$. We show that, information theoretically, none of these parameters can be substantially improved without dramatically affecting the others. Furthermore, we obtain several explicit constructions, in particular one matching the randomized trade-off but using $m = O(d^{1+o(1)} \log n)$ measurements. We also obtain explicit constructions that allow fast reconstruction in time \poly(m), which would be sublinear in $n$ for sufficiently sparse vectors. The main tool used in our construction is the list-decoding view of randomness condensers and extractors.Comment: Full version. A preliminary summary of this work appears (under the same title) in proceedings of the 17th International Symposium on Fundamentals of Computation Theory (FCT 2009