Limits on Pop III star formation with the most iron-poor stars

We study the impact of star-forming mini-haloes, and the Initial Mass Function (IMF) of Population III (Pop III) stars, on the Galactic halo Metallicity Distribution Function (MDF) and on the properties of C-enhanced and C-normal stars at [Fe/H]<-3. For our investigation we use a data-constrained merger tree model for the Milky Way formation, which has been improved to self-consistently describe the physical processes regulating star-formation in mini-haloes, including the poor sampling of the Pop III IMF. We find that only when star-forming mini-haloes are included the low-Fe tail of the MDF is correctly reproduced, showing a plateau that is built up by C-enhanced metal-poor (CEMP) stars imprinted by primordial faint supernovae. The incomplete sampling of the Pop III IMF in inefficiently star-forming mini-haloes (< $10^{-3}$ $M_\odot$/yr) strongly limits the formation of Pair Instability Supernovae (PISNe), with progenitor masses $m_{\rm popIII}$=[140-260] $M_\odot$, even when a flat Pop III IMF is assumed. Second-generation stars formed in environments polluted at >50% level by PISNe are thus extremely rare, corresponding to $\approx$ 0.25% of the total stellar population at [Fe/H]<-2, which is consistent with recent observations. The low-Fe tail of the MDF strongly depends on the Pop III IMF shape and mass range. Given the current statistics, we find that a flat Pop III IMF model with $m_{\rm popIII}$=[10-300] $M_\odot$ is disfavoured by observations. We present testable predictions for Pop III stars extending down to lower masses, with $m_{\rm popIII}$=[0.1-300] $M_\odot$.Comment: 15 pages, 11 figures. Accepted for publication in MNRAS. The only change is the correction of a mistake in the list of author

A spatiotemporal object-oriented data model for landslides (LOOM)

LOOM (landslide object-oriented model) is here presented as a data structure for landslide inventories based on the object-oriented paradigm. It aims at the effective storage, in a single dataset, of the complex spatial and temporal relations between landslides recorded and mapped in an area and at their manipulation. Spatial relations are handled through a hierarchical classification based on topological rules and two levels of aggregation are defined: (i) landslide complexes, grouping spatially connected landslides of the same type, and (ii) landslide systems, merging landslides of any type sharing a spatial connection. For the aggregation procedure, a minimal functional interaction between landslide objects has been defined as a spatial overlap between objects. Temporal characterization of landslides is achieved by assigning to each object an exact date or a time range for its occurrence, integrating both the time frame and the event-based approaches. The sum of spatial integrity and temporal characterization ensures the storage of vertical relations between landslides, so that the superimposition of events can be easily retrieved querying the temporal dataset. The here proposed methodology for landslides inventorying has been tested on selected case studies in the Cilento UNESCO Global Geopark (Italy). We demonstrate that the proposed LOOM model avoids data fragmentation or redundancy and topological inconsistency between the digital data and the real-world features. This application revealed to be powerful for the reconstruction of the gravity-induced deformation history of hillslopes, thus for the prediction of their evolution

Dust from AGBs: relevant factors and modelling uncertainties

The dust formation process in the winds of Asymptotic Giant Branch stars is discussed, based on full evolutionary models of stars with mass in the range $1$M$_{\odot} \leq$M$\leq 8$M$_{\odot}$, and metallicities $0.001 < Z <0.008$. Dust grains are assumed to form in an isotropically expanding wind, by growth of pre--existing seed nuclei. Convection, for what concerns the treatment of convective borders and the efficiency of the schematization adopted, turns out to be the physical ingredient used to calculate the evolutionary sequences with the highest impact on the results obtained. Low--mass stars with M$\leq 3$M$_{\odot}$ produce carbon type dust with also traces of silicon carbide. The mass of solid carbon formed, fairly independently of metallicity, ranges from a few $10^{-4}$M$_{\odot}$, for stars of initial mass $1-1.5$M$_{\odot}$, to $\sim 10^{-2}$M$_{\odot}$ for M$\sim 2-2.5$M$_{\odot}$; the size of dust particles is in the range $0.1 \mu$m$\leq a_C \leq 0.2\mu$m. On the contrary, the production of silicon carbide (SiC) depends on metallicity. For $10^{-3} \leq Z \leq 8\times 10^{-3}$ the size of SiC grains varies in the range $0.05 \mu {\rm m} < {\rm a_{SiC}} < 0.1 \mu$m, while the mass of SiC formed is $10^{-5}{\rm M}_{\odot} < {\rm M_{SiC}} < 10^{-3}{\rm M}_{\odot}$. Models of higher mass experience Hot Bottom Burning, which prevents the formation of carbon stars, and favours the formation of silicates and corundum. In this case the results scale with metallicity, owing to the larger silicon and aluminium contained in higher--Z models. At Z=$8\times 10^{-3}$ we find that the most massive stars produce dust masses $m_d \sim 0.01$M$_{\odot}$, whereas models of smaller mass produce a dust mass ten times smaller. The main component of dust are silicates, although corundum is also formed, in not negligible quantities ($\sim 10-20\%$).Comment: Paper accepted for publication in Monthly Notices of the Royal Astronomical Society Main Journal (2014 January 4

Contact-dependent Stimulation and Inhibition of Dendritic Cells by Natural Killer Cells

Natural killer (NK) cells and dendritic cells (DCs) are two distinct cell types of innate immunity. It is known that the in vitro interaction of human NK cells with autologous DCs results in DC lysis. Here we show that contact-dependent interactions between activated human NK cells and immature DCs (iDCs) provides a “control switch” for the immune system. At low NK/DC ratios, this interaction dramatically amplifies DC responses, whereas at high ratios it completely turns off their responses. Specifically, culture of activated human NK cells with iDCs, at low NK/DC ratios (1:5), led to exponential increases in DC cytokine production, which were completely dependent on cell-to-cell contact. DC maturation was also driven by cognate interactions with NK cells and maturation was dependent on endogenously produced TNF-α in the culture. At slightly higher NK/DC ratios (5:1), inhibition of DC functions was the dominant feature due to potent killing by the autologous NK cells. Resting NK cells also stimulated autologous DC maturation in a TNF-α/contact-dependent manner, however, increasing the NK/DC ratio only led to an enhancement of this effect

AGB and SAGB stars: modelling dust production at solar metallicity

We present dust yields for asymptotic giant branch (AGB) and super--asymptotic giant branch (SAGB) stars of solar metallicity. Stars with initial mass $1.5~M_{\odot} \leq M_{\rm ini} \leq 3~M_{\odot}$ reach the carbon star stage during the AGB phase and produce mainly solid carbon and SiC. The size and the amount of the carbon particles formed follows a positive trend with themass of the star; the carbon grains with the largest size ($a_{\rm C} \sim 0.2\mu$m) are produced by AGB stars with $M_{\rm ini} = 2.5-3~M_{\odot}$, as these stars are those achieving the largest enrichment of carbon in the surface regions. The size of SiC grains, being sensitive to the surface silicon abundance, keeps around $a_{\rm SiC} \sim 0.1\mu$m. The mass of carbonaceous dust formed is in the range $10^{-4} - 5\times 10^{-3}~M_{\odot}$, whereas the amount of SiC produced is $2\times 10^{-4} - 10^{-3}~M_{\odot}$. Massive AGB/SAGB stars with $M_{\rm ini} > 3~M_{\odot}$ experience HBB, that inhibits formation of carbon stars. The most relevant dust species formed in these stars are silicates and alumina dust, with grain sizes in the range $0.1\mu m < a_{\rm ol} < 0.15\mu$m and $a_{\rm Al_2O_3} \sim 0.07\mu$m, respectively. The mass of silicates produced spans the interval $3.4\times 10^{-3}~M_{\odot} \leq M_{\rm dust} \leq 1.1\times 10^{-2}~M_{\odot}$ and increases with the initial mass of the star.Comment: Accepted for publication in MNRA

Interference of dibutylphthalate on human prostate cell viability

Dibutylphthalate (DBP) is an environmental pollutant widely used as plasticizer in a variety of industrial applications worldwide. This agent can be found in personal-care products, children's toy, pharmaceuticals, food products. Exposure to DBP can occur via ingestion and inhalation as well as intravenous or skin contact. DBP belongs to the family of endocrine disrupting chemicals (EDCs) and its effects on reproductive system were demonstrated both in vivo and in vitro. In the present study we evaluated the effects of DBP on human prostate adenocarcinoma epithelial cells (LNCaP) in order to highlight xenoestrogens influence on human prostate. Moreover, we have compared DBP effects with 17β-estradiol action in order to investigate possible mimetical behaviour. We have assessed the effects of both compounds on the cell viability. After then, we have evaluated the expression of genes and proteins involved in cell cycle regulation. Furthermore, we have observed the expression and the cell localization of estrogen (ERs) and androgen (AR) receptors. In conclusion, we have demonstrated that DBP interacts with estrogen hormonal receptor pathway but differently from E2. DBP alters the normal gland physiology and it is involved in the deregulation of prostate cell cycle

OctylPhenol (OP) Alone and in Combination with NonylPhenol (NP) Alters the Structure and the Function of Thyroid Gland of the Lizard Podarcis siculus

Abstract: Different environmental contaminants disturb the thyroid system at many levels. AlkylPhenols (APs), by-products of microbial degradation of AlkylPhenol Polyethoxylates (APEOs), constitute an important class of Endocrine Disrupting Chemicals (EDCs), the two most often used environmental APs being 4-nonylphenol (4-NP) and 4-tert-octylphenol (4-t-OP). The purpose of the present study was to investigate the effects on the thyroid gland of the bioindicator Podarcis siculus of OP alone and in combination with NP. We used radioimmunoassay to determine their effects on plasma 3,3′,5-triiodo-L-thyronine (T3), 3,3′,5,5′-L-thyroxine (T4), thyroid-stimulating hormone (TSH), and thyrotropin-releasing&nbsp;hormone (TRH) levels in adult male lizards. We also investigated the impacts of AP treatments on hepatic 5′ORD (type II) deiodinase and hepatic content of T3 and T4. After OP and OP + NP administration, TRH levels increased, whereas TSH, T3, and T4 levels decreased. Lizards treated with OP and OP + NP had a higher concentration of T3 in the liver and 5′ORD (type II) activity, whereas T4 concentrations were lower than that observed in the control group. Moreover, histological examination showed that the volume of the thyroid follicles became smaller in treated lizards suggesting that that thyroid follicular epithelial cells were not functionally active following treatment. This data collectively suggest a severe interference with hypothalamus–pituitary–thyroid axis and a systemic imbalance of thyroid hormones. Graphic Abstract: [Figure not available: see fulltext.

Killer Cell Inhibitory Receptor Recognition of Human Leukocyte Antigen (HLA) Class I Blocks Formation of a pp36/PLC-γ Signaling Complex in Human Natural Killer (NK) Cells

The killer cell inhibitory receptors (KIR) of human natural killer (NK) cells recognize human leukocyte antigen class I molecules and inhibit NK cell cytotoxicity through their interaction with protein tyrosine phosphatases (PTP). Here, we report that KIR recognition of class I ligands inhibits distal signaling events and ultimately NK cell cytotoxicity by blocking the association of an adaptor protein (pp36) with phospholipase C-γ in NK cells. In addition, we demonstrate that pp36 can serve as a substrate in vitro for the KIR-associated PTP, PTP-1C (also called SHP-1), and that recognition of class I partially disrupts tyrosine phosphorylation of NK cell proteins, providing evidence for KIR-induced phosphatase activity

A NWB-based dataset and processing pipeline of human single-neuron activity during a declarative memory task

A challenge for data sharing in systems neuroscience is the multitude of different data formats used. Neurodata Without Borders: Neurophysiology 2.0 (NWB:N) has emerged as a standardized data format for the storage of cellular-level data together with meta-data, stimulus information, and behavior. A key next step to facilitate NWB:N adoption is to provide easy to use processing pipelines to import/export data from/to NWB:N. Here, we present a NWB-formatted dataset of 1863 single neurons recorded from the medial temporal lobes of 59 human subjects undergoing intracranial monitoring while they performed a recognition memory task. We provide code to analyze and export/import stimuli, behavior, and electrophysiological recordings to/from NWB in both MATLAB and Python. The data files are NWB:N compliant, which affords interoperability between programming languages and operating systems. This combined data and code release is a case study for how to utilize NWB:N for human single-neuron recordings and enables easy re-use of this hard-to-obtain data for both teaching and research on the mechanisms of human memory

Neurocognitive and Seizure Outcomes of Selective Amygdalohippocampectomy versus Anterior Temporal Lobectomy for Mesial Temporal Lobe Epilepsy.

Objective. To report our institutional seizure and neuropsychological outcomes for a series of patients with mesial temporal lobe epilepsy (mTLE) undergoing anterior temporal lobectomy (ATL) or selective amygdalohippocampectomy (SelAH) between 2004 and 2011. Methods. A retrospective study of patients with mTLE was conducted. Seizure outcome was reported using time-to-event analysis. Cognitive outcome was reported using the change principal in component factor scores, one each, for intellectual abilities, visuospatial memory, and verbal memory. The Boston Naming Test was used for naming assessment. Language dominant and nondominant resections were compared separately. Student's t-test was used to assess statistical significance. Results. Ninety-six patients (75 ATL, 21 SelAH) were included; fifty-four had complete neuropsychological follow-up. Median follow-up was 40.5 months. There was no statistically significant difference in seizure freedom or any of the neuropsychological outcomes, although there was a trend toward greater postoperative decline in naming in the dominant hemisphere group following ATL. Conclusion. Seizure and neuropsychological outcomes did not differ for the two surgical approaches which is similar to most prior studies. Given the theoretical possibility of SelAH sparing language function in patients with epilepsy secondary to mesial temporal sclerosis and the limited high-quality evidence creating equipoise, a multicenter randomized clinical trial is warranted