215 research outputs found

    Cephalic salt gland evolution in Mesozoic pelagic crocodylomorphs

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    Secondarily marine tetrapod lineages have independently evolved osmoregulatory adaptations for life in salt water but inferring physiological changes in extinct marine tetrapods is difficult. The Mesozoic crocodylomorph clade Thalattosuchia is unique in having both direct evidence from natural endocasts and several proposed osteological correlates for salt exocrine glands. Here, we investigate salt gland evolution in thalattosuchians by creating endocranial reconstructions from CT scans of eight taxa (one basal thalattosuchian, one teleosauroid, two basal metriorhynchoids and four metriorhynchids) and four outgroups (three extant crocodylians and the basal crocodyliform Protosuchus) to identify salt gland osteological correlates. All metriorhynchoids show dorsolateral nasal cavity expansions corresponding to the location of nasal salt glands in natural casts, but smaller expansions in teleosauroids correspond more with the cartilaginous nasal capsule. The different sizes of these expansions suggest the following evolutionary sequence: (1) plesiomorphically small glands present in semi-aquatic teleosauroids draining through the nasal vestibule; (2) moderately sized glands in the basalmost metriorhynchoid Pelagosaurus; and (3) hypertrophied glands in the clade comprising Eoneustes and metriorhynchids, with a pre-orbital fenestra providing a novel exit for salt drainage. The large gland size inferred from basal metriorhynchoids indicates advanced osmoregulation occurred while metriorhynchoids were semi-aquatic. This pattern does not precisely fit into current models of physiological evolution in marine tetrapods and suggests a unique sequence of changes as thalattosuchians transitioned from land to sea.Fil: Cowgill, T.. University of Edinburgh; Reino UnidoFil: Young, M.. University of Edinburgh; Reino UnidoFil: Schwab, J.. University of Edinburgh; Reino UnidoFil: Walsh, S.. National Museum Of Scotland; Reino UnidoFil: Witmer, Lawrence. Ohio University; Estados UnidosFil: Herrera, Laura Yanina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. DivisiĂłn PaleontologĂ­a Vertebrados; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata; ArgentinaFil: Dollman, K.. University of the Witwatersrand; SudĂĄfricaFil: Turner, A. H.. State University of New York. Stony Brook University; Estados UnidosFil: Brusatte, S.. University of Edinburgh; Reino Unid

    “They Aren’t Going to Do Jack Shit”: Text-Based Crisis Service Users’ Perceptions of Seeking Child Maltreatment-Related Support From Formal Systems

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    Many of the children reported to child protective services (CPS) exhibit signs and symptoms that allow others to recognize their abuse or neglect and intervene; others, especially adolescents, must disclose their experiences to be identified. Relatively little is known about young people’s disclosure experiences, but individual, interpersonal, and cultural factors appear to influence when and how young people disclose. Technology-facilitated approaches, such as text- or chat-based hotlines or crisis services, may be one way to help young people share their maltreatment experiences and seek help. The current study contributes to the small body of literature that includes nonsexual maltreatment disclosures and sheds some light on how to support young people during their disclosures. We conducted a qualitative content analysis of all conversations from a text-based crisis service that resulted in a report to CPS (n = 244). Many of the texters had previously sought support from their peers or parents, and some had engaged with more formal systems. Many young people were hesitant to reach out to formal systems in the future, in part because of negative experiences during past disclosure experiences. Young people may be more likely to seek support through their preferred communication medium, so providing text- and chat-based communication may be one way to encourage and facilitate disclosure. As these resources become increasingly available, determining best practices for receiving disclosures through technology-facilitated platforms will be critical

    Continental Origin for Q Haplogroup Patrilineages in Argentina and Paraguay

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    Haplogroup Q originated in Eurasia around 30,000 years ago. It is present in Y-chromosomes from Asia and Europe at rather low frequencies. Since America is undoubtedly one of the continents where this haplogroup is highly represented, it has been defined as one of the founding haplogroups. Its M3 clade has been early described as the most frequent, with Pan-American representation. However, it was also possible to find several other haplogroup Q clades at low frequencies. Numerous mutations have been described for haplogroup Q, allowing the analysis of its variability and the assignment of its geographic origin. We have analyzed 442 samples belonging to haplogroup Q of unrelated men from Argentina and Paraguay, but this work is specifically referred to 27 Q (xM3) lineages. We tested 3 SNPs by APLP, 3 for RFLP, 15 SNPs by Sanger sequencing, and 17 STRs. Our approach allowed us to identify 5 sub-haplogroups. Q-M3 and Q-CTS2730/Z780 are undoubtedly autochthonous lineages and represent the most frequent sub-haplogroups. With significant representation in self-defined aboriginal populations, their autochthonous status has been previously described. The aim of present work is to identify the continental origin of the remaining Q lineages. Thus, we analyzed the STR haplotypes for the samples of our series and compared them with haplotypes described by other authors for the rest of the world. Even when haplogroup Qs have been extensively studied in America, some of them could have their origin in post Columbian human migration from Europe and Middle East

    Mammalian Whiskers and the Euler Spiral

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    Mammal whiskers are often used as a model for understanding the sensory circuits in the brain. Signals from the whiskers, especially their forces, are processed throughout the brain, particularly in the somatosensory “barrel” cortex. Before attempting to interpret the neuronal signals, it is imperative to understand the signals received by the whisker follicles themselves and therefore accurately modelling whisker mechanics is important. Previously, whiskers have been modelled as a parabola based on Cartesian coordinates of the whisker centerline, but we propose that an Euler spiral model is a simple way to capture many aspects of whisker shape. In this study, we model 516 rat (Rattus norvegicus) whiskers as plane model curves with a linear relationship between arc length, s, and curvature, k, such that k(s) = A(s) + B and show that any original rat whisker can be mapped onto a normalized Euler spiral. The Euler spiral provides a convenient and highly accurate model for analytical studies, particularly intrinsically curved rods such as whiskers. The simplistic description in terms of coefficients A and B allows average whiskers to be created from data sets. In addition, vibrissae of many different species, such as pygmy shrew or grey seal, can be readily compared based on their shape alone

    ‘Ear stones’ in crocodylians: a cross-species comparative and ontogenetic survey of otolith structures

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    The vestibular system of the inner ear is a crucial sensory organ, involved in the sensation of balance and equilibrium. It consists of three semicircular canals that sense angular rotations of the head and the vestibule that detects linear acceleration and gravity. The vestibule often contains structures, known as the otoliths or ‘ear stones’. Otoliths are present in many vertebrates and are particularly well known from the fossil record of fish, but surprisingly have not been described in detail in most tetrapods, living or extinct. Here, we present for the first time a survey of the otoliths of a broad sample of extant crocodylian species, based on computed tomography scans. We find that otoliths are present in numerous crocodylian species of different growth stages, and they continue to increase in size during ontogeny, with positive allometry compared to skull length. Our results confirm that otoliths are a common component of the crocodylian vestibular system, and suggest they play an important role in sensory detection. Otoliths are likely common, but overlooked, constituents of the inner ear in tetrapods, and a broader study of their size, shape and distribution promises insight into sensory abilities.Facultad de Ciencias Naturales y Muse

    Study of exclusive one-pion and one-eta production using hadron and dielectron channels in pp reactions at kinetic beam energies of 1.25 GeV and 2.2 GeV with HADES

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    We present measurements of exclusive ensuremathπ+,0 and η production in pp reactions at 1.25GeV and 2.2GeV beam kinetic energy in hadron and dielectron channels. In the case of π+ and π0 , high-statistics invariant-mass and angular distributions are obtained within the HADES acceptance as well as acceptance-corrected distributions, which are compared to a resonance model. The sensitivity of the data to the yield and production angular distribution of Δ (1232) and higher-lying baryon resonances is shown, and an improved parameterization is proposed. The extracted cross-sections are of special interest in the case of pp → pp η , since controversial data exist at 2.0GeV; we find \ensuremathσ=0.142±0.022 mb. Using the dielectron channels, the π0 and η Dalitz decay signals are reconstructed with yields fully consistent with the hadronic channels. The electron invariant masses and acceptance-corrected helicity angle distributions are found in good agreement with model predictions

    Three Hypervelocity White Dwarfs in Gaia DR2: Evidence for Dynamically Driven Double-Degenerate Double-Detonation Type Ia Supernovae

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    Double detonations in double white dwarf (WD) binaries undergoing unstable mass transfer have emerged in recent years as one of the most promising Type Ia supernova (SN Ia) progenitor scenarios. One potential outcome of this "dynamically driven double-degenerate double-detonation" (D^6) scenario is that the companion WD survives the explosion and is flung away with a velocity equal to its > 1000 km/s pre-SN orbital velocity. We perform a search for these hypervelocity runaway WDs using Gaia's second data release. In this paper, we discuss seven candidates followed up with ground-based instruments. Three sources are likely to be some of the fastest known stars in the Milky Way, with total Galactocentric velocities between 1000 and 3000 km/s, and are consistent with having previously been companion WDs in pre-SN Ia systems. However, although the radial velocity of one of the stars is > 1000 km/s, the radial velocities of the other two stars are puzzlingly consistent with 0. The combined five-parameter astrometric solutions from Gaia and radial velocities from follow-up spectra yield tentative 6D confirmation of the D^6 scenario. The past position of one of these stars places it within a faint, old SN remnant, further strengthening the interpretation of these candidates as hypervelocity runaways from binary systems that underwent SNe Ia.Comment: Accepted for publication in ApJ. Minor corrections for clarity. D6 spectra are available as ancillary data file

    Reconstruction of Endometrium from Human Endometrial Side Population Cell Lines

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    Endometrial regeneration is mediated, at least in part, by the existence of a specialized somatic stem cell (SSC) population recently identified by several groups using the side population (SP) technique. We previously demonstrated that endometrial SP displays genotypic, phenotypic and the functional capability to develop human endometrium after subcutaneous injection in NOD-SCID mice. We have now established seven human endometrial SP (hESP) cell lines (ICE 1–7): four from the epithelial and three from the stromal fraction, respectively. SP cell lines were generated under hypoxic conditions based on their cloning efficiency ability, cultured for 12–15 passages (20 weeks) and cryopreserved. Cell lines displayed normal 46XX karyotype, intermediate telomerase activity pattern and expressed mRNAs encoding proteins that are considered characteristic of undifferentiated cells (Oct-4, GDF3, DNMT3B, Nanog, GABR3) and those of mesodermal origin (WT1, Cardiac Actin, Enolase, Globin, REN). Phenotype analysis corroborated their epithelial (CD9+) or stromal (vimentin+) cell origin and mesenchymal (CD90+, CD73+ and CD45−) attributes. Markers considered characteristic of ectoderm or endoderm were not detected. Cells did not express either estrogen receptor alpha (ERα) or progesterone receptor (PR). The hESP cell lines were able to differentiate in vitro into adipocytes and osteocytes, which confirmed their mesenchymal origin. Finally, we demonstrated their ability to generate human endometrium when transplanted beneath the renal capsule of NOD-SCID mice. These findings confirm that SP cells exhibit key features of human endometrial SSC and open up new possibilities for the understanding of gynecological disorders such as endometriosis or Asherman syndrome. Our cell lines can be a valuable model to investigate new targets for endometrium proliferation in endometriosis

    Arterial line pressure control enhanced extracorporeal blood flow prescription in hemodialysis patients

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    <p>Abstract</p> <p>Background</p> <p>In hemodialysis, extracorporeal blood flow (Qb) recommendation is 300–500 mL/min. To achieve the best Qb, we based our prescription on dynamic arterial line pressure (DALP).</p> <p>Methods</p> <p>This prospective study included 72 patients with catheter Group 1 (G1), 1877 treatments and 35 arterio-venous (AV) fistulae Group 2 (G2), 1868 treatments. The dialysis staff was trained to prescribe Qb sufficient to obtain DALP between -200 to -250 mmHg. We measured ionic clearance (IK: mL/min), access recirculation, DALP (mmHg) and Qb (mL/min). Six prescription zones were identified: from an optimal A zone (Qb > 400, DALP -200 to -250) to zones with lower Qb E (Qb < 300, DALP -200 to -250) and F (Qb < 300, DALP > -199).</p> <p>Results</p> <p>Treatments distribution in A was 695 (37%) in G1 vs. 704 (37.7%) in G2 (<it>P </it>= 0.7). In B 150 (8%) in G1 vs. 458 (24.5%) in G2 (<it>P </it>< 0.0001). Recirculation in A was 10.0% (Inter quartile rank, IQR 6.5, 14.2) in G1 vs. 9.8% (IQR 7.5, 14.1) in G2 (<it>P </it>= 0.62). IK in A was 214 ± 34 (G1) vs. 213 ± 35 (G2) (<it>P </it>= 0.65). IK Anova between G2 zones was: A vs. C and D (<it>P </it>< 0.000001). Staff prescription adherence was 81.3% (G1) vs. 84.1% (G2) (<it>P </it>= 0.02).</p> <p>Conclusion</p> <p>In conclusion, an optimal Qb can de prescribed with DALP of -200 mmHg. Staff adherence to DLAP treatment prescription could be reached up to 81.3% in catheters and 84.1% in AV fistulae.</p
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