204 research outputs found

    Among- and within-population variation in sperm quality in the simultaneously hermaphroditic land snail Arianta arbustorum

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    Sperm competition models on the evolution of sperm size assume associations with another sperm quality trait, sperm longevity. Sperm length can also provide an indication of possible mechanisms affecting motility and thus fertilization success. Despite their importance, however, detailed mechanisms of sperm competition at the gamete level are poorly understood. In simultaneously hermaphroditic land snails, sperm traits and cryptic female choice are assumed to be crucial in determining fertilization success. We examined the variation in sperm length and number among individuals from four natural populations of the land snail Arianta arbustorum, a species with multiple mating and long-term sperm storage. We also assessed variation in velocity, motility and longevity of sperm in snails from two of the four populations. Independent of shell size, sperm length differed among populations and, to a minor extent, even among individuals within populations. Mean sperm length of a snail was not correlated with the number of sperm delivered in a spermatophore. The mean sperm velocity (=VCL) did not differ between snails from two populations. However, VCL varied among snails. Percentage motility and longevity of sperm differed between snails from the two populations. No correlations were found between length, velocity, percentage motility and longevity of sperm. To conclude, individual snails differed in sperm quality, and this variation may partly explain the differential fertilization success between A. arbustorum snails. Moreover, our findings did not support the positive association between sperm length and longevity assumed by sperm competition models for internally fertilizing specie

    IL RICONOSCIMENTO DELLA DOMANDA

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    The following paper regards the aknowledgment of claim that could be implemented by the defendant after been notified about plaintiff\u2019s claim and for the whole duration of trial as well. The previous legal institution is not expressly ruled by the italian civil procedure and for these reasons it\u2019s definitely necessary to identify and fix the nature and the effects of that institution that involve the consequent judgment. Considering the Scholars\u2019 positions and the line of cases, the objective of the present work is therefore to rebuild the institution of the aknowledgment of claim as an evidence of the principles of party disposition and procedural economy. Actually it\u2019s considered that the parties, in the presence of the acknowledgment of claim and the principle of procedural economy, are supposed to bind the judge\u2019s decision according to the mentioned acknowledgment in order to grant the plaintiff\u2019s motion

    Heritability of sperm length and adult shell size in the land snail Arianta arbustorum (Linnaeus, 1758)

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    Sperm length varies considerably, both between and within species, but the evolutionary implications of this variation are poorly understood. Sexual selection on sperm length requires a significant additive genetic variance, but few studies have actually measured this. Stylommatophoran gastropods have extraordinarily long sperm. However, the extent of intraspecific variation has rarely been examined. Here we present the first estimates of heritability of sperm length in the land snail Arianta arbustorum using two complementary approaches (one-parent-offspring regression and full-sibling split design). We also examined whether sperm length is influenced by the shell size of the snail and estimated heritability of shell size. Sperm delivered by the same individuals in 2-4 matings over two reproductive seasons did not differ in length, indicating a high repeatability of this trait. Offspring of 10 families were kept at three temperatures (11, 15 and 20°C) to examine the influence of different environmental conditions on sperm length and adult shell breadth. Independent of shell breadth, sperm length was affected by temperature but not by family of origin (the variance component associated with family was not significantly different from zero), while adult shell breadth was influenced by temperature and family of origin. Higher temperatures resulted in shorter sperm, but larger shells. The heritability of sperm length derived from the two different approaches (one-parent-offspring regression: h2 ± SE = 0.52 ± 0.55; full-sibling split design: H2 ± SE = −0.19 ± 0.28) suggests relatively little genetic variation in this trait in the studied population. In contrast, the heritability of adult shell breadth indicates a strong genetic effect (mother-offspring regression, h2 ± SE = 0.90 ± 0.33). The heritability (h2 ± SE) of adult shell breadth obtained from the father-offspring regression was 0.18 ± 0.42, i.e. five times smaller than that of the mother-offspring regression, suggesting a maternal effect on shell siz

    A predictive index of intra-dialysis IDH. A statistical clinical data mining approach.

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    Intra-Dialysis Hypotension (IDH) is one of the main hemodialysis related complications, occurring in 25-30% of the sessions. The factors involved in the onset of hypotension in patients undergoing dialysis are due both to clinical conditions (e.g. presence of vascular or cardiac diseases, neuropathology, anemia) and treatment settings such as temperature of the dialysate, sodium concentration, buffer composition, ultrafiltration rate, etc. The patient’s peculiar reaction to the treatment implies difficulties in preventing IDH episodes. This work explores the possibility to use a multivariate analysis of clinical data to quantify the risk to develop IDH at the beginning of each session. The study is framed in the DialysIS project (Dialysis therapy between Italy and Switzerland) funded by INTERREG – Italy – Switzerland and Co-funded by European Union. Data referring to a total of 516 sessions performed on 70 adult patients undergoing dialysis treatment (50 patients enrolled at A. Manzoni Hospital Lecco, Italy and 20 patients at Regional Hospital of Lugano, Switzerland) were collected. Clinical prescriptions, hydration status, dialysis machine data and hematochemical data were recorded and stored in a unique flexible structured MySQL® database. A statistical analysis was performed to find the potential risk factor related to IDH onset. IDH episodes were automatically detected during the monitored sessions, according to the literature criteria. Patients suffering from IDH in 2 or more sessions were classified as Hypotension Prone (HP), the others as Hypotension Resistant (HR). Initial values of potassium concentration [K+], systolic (SBP) and diastolic (DBP) blood pressure, and weight gain (ΔW) from the end of the previous treatment result to be statistically different between the HP and HR groups. A new index, J, was defined as a weighted patient-specific combination of these parameters and calculated for each session of each patient. The weight of the index coefficients can be dynamically adjourned based on the longitudinal analysis of [K+], SBP, DBP, and ΔW. The results reported in this paper were calculated based on a longitudinal analysis of a minimum of three sessions for each patient. The accuracy of the J index in predicting IDH events has been evaluated and quantified in terms of percentage number of predicted IDH events, with respect to the total number of IDHs. Values of J index higher than 1 point out the risk of IDH onset. J allows the prediction of 100% of IDH episodes using 5 sessions, the 90% using 3 sessions. More specifically, at Lecco Hospital 43 IDH events were detected by the automatic system of which 100% and 95% were respectively predicted by the new index calculated using 5 or 3 sessions. Similarly, at Lugano Hospital 58 IDH were detected by the automatic system of which 100% and 87,5% were predicted using 5 or 3 sessions respectively. A longer longitudinal dataset will allow a higher matching of J to actual IDH episodes. In conclusion, the evaluation of this new index at the beginning of the dialysis session prior to connecting the patient to the machine can provide the clinician with useful information about the risk for the patient to develop cardiovascular instabilities (IDH) during the treatment and can advise the physician about the need to modify the prescription

    Visor Osteotomy of the Anterior Mandible

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    Current techniques for three-dimensional correction of the chin in patients with mandibular retrusion may increase mentolabial fold depth, but have limited effect on the lips. The authors present a single surgical technique to support the mentolabial fold and improve labial competence. The visor osteotomy is performed from canine to canine. The bone fragment pedicled to the lingual periosteum is coronally mobilized and fixed in the new position. Preserved vascularization is supposed to minimize the amount of bone resorbed. Visor osteotomy of the anterior mandible may improve the existing treatments for micrognathia by creating an aesthetic mentolabial fold and a competent lip seal

    Determination of dipole coupling constants using heteronuclear multiple quantum NMR

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    The problem of extracting dipole couplings from a system of N spins I = 1/2 and one spin S by NMR techniques is analyzed. The resolution attainable using a variety of single quantum methods is reviewed. The theory of heteronuclear multiple quantum (HMQ) NMR is developed, with particular emphasis being placed on the superior resolution available in HMQ spectra. Several novel pulse sequences are introduced, including a two-step method for the excitation of HMQ coherence. Experiments on partially oriented [1−13C] benzene demonstrate the excitation of the necessary HMQ coherence and illustrate the calculation of relative line intensities. Spectra of high order HMQ coherence under several different effective Hamiltonians achievable by multiple pulse sequences are discussed. A new effective Hamiltonian, scalar heteronuclear recoupled interactions by multiple pulse (SHRIMP), achieved by the simultaneous irradiation of both spin species with the same multiple pulse sequence, is introduced. Experiments are described which allow heteronuclear couplings to be correlated with an S-spin spreading parameter in spectra free of inhomogeneous broadening

    Single-center open-label randomized study of anemia management improvement in ESRD patients with secondary hyperparathyroidism

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    Whether anemia and mineral bone abnormalities (chronic kidney disease\u2013mineral bone disorder [CKD-MBD]) are associated still remains to be elucidated. Both anemia and CKD-MBD have been associated with adverse cardiovascular outcome and poor quality of life. However, recent evidence suggests that use of large doses of erythropoietin-stimulating agents (ESAs) to correct hemoglobin (Hb) may be detrimental in CKD. The Optimal Anemia Treatment in End Stage Renal Disease (ESRD) (Optimal ESRD Treatment) study will assess whether lowering of parathyroid hormone (PTH) is associated with a reduction in ESA consumption. The Optimal ESRD Treatment study is a pilot single-center open-label study with blinded end point (a prospective randomized open blinded end-point [PROBE] design) enrolling 50 patients on maintenance dialysis. Eligible patients with intact PTH (iPTH) 300-540 pg/mL and Hb 10-11.5 g/dL will be randomized 1:1 to strict PTH control (150-300 pg/mL) versus standard care (PTH range 300-540 pg/mL). Available drugs for CKD-MBD and anemia treatment will be managed by the attending physician to maintain the desired levels of PTH (according to study arm allocation) and Hb (10-11.5 g/dL). Echocardiographic data for cardiac structure and function as well as arterial stiffness will be assessed at study inception and completion. The Optimal ESRD Treatment study should shed light on the complicated interplay of anemia and CKD-MBD and on the feasibility of clinical trials in this domain. The study results are expected in the spring of 2017

    Sperm design and variation in the New World blackbirds (Icteridae)

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    Post-copulatory sexual selection (PCSS) is thought to be one of the evolutionary forces responsible for the rapid and divergent evolution of sperm design. However, whereas in some taxa particular sperm traits are positively associated with PCSS, in other taxa, these relationships are negative, and the causes of these different patterns across taxa are poorly understood. In a comparative study using New World blackbirds (Icteridae), we tested whether sperm design was influenced by the level of PCSS and found significant positive associations with the level of PCSS for all sperm components but head length. Additionally, whereas the absolute length of sperm components increased, their variation declined with the intensity of PCSS, indicating stabilizing selection around an optimal sperm design. Given the diversity of, and strong selection on, sperm design, it seems likely that sperm phenotype may influence sperm velocity within species. However, in contrast to other recent studies of passerine birds, but consistent with several other studies, we found no significant link between sperm design and velocity, using four different species that vary both in sperm design and PCSS. Potential reasons for this discrepancy between studies are discussed
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