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On 14 September 2022, the European Commission presented a proposal for a Regulation (Proposal for a Regulation of the European Parliament and of the Council banning products made with forced labour on the Union market, COM (2022) 453 final of 14 September 2022, https://eurlex. europa.eu/legal-content/EN/TXT/?uri=CELEX%3A52022PC0453) aimed at banning from the EU market products made with forced labour. The proposal – which concerns both imported products and those manufactured in the Union territory to be destined for internal consumption or export and does not focus on specific types of enterprises, thus also affecting very small ones – will now have to be discussed and approved by the European Union Parliament and Council to become an effective legislative act and will apply after twenty-four months from its entry into force. The Regulation Proposal of the European Commission appears to be wide-ranging, and doesn’t identify – at least in this first phase – specific product categories or certain producer countries, unlike what was decided by other countries (For example, the United States of America, in the framework of the bans on the import of goods made with forced labour, on 21 June 2022 adopted the Uyghur Forced Labor Prevention Act (UFLPA), which tightens the ban on imports into the USA for products made with forced labour in China, particularly in the Xinjiang Uyghur Autonomous Region). The most immediate effect of the desirable approval of the Proposal in question will be represented, for Union economic operators, by the need to carry out even more careful due diligence on supply chains and, more generally, on the reliability of their suppliers, in order to mitigate the risks of placing on the market products obtained by resorting to modern slavery.

On 14 September 2022, the European Commission presented a proposal for a Regulation (Proposal for a Regulation of the European Parliament and of the Council banning products made with forced labour on the Union market, COM (2022) 453 final of 14 September 2022, https://eurlex. europa.eu/legal-content/EN/TXT/?uri=CELEX%3A52022PC0453) aimed at banning from the EU market products made with forced labour. The proposal – which concerns both imported products and those manufactured in the Union territory to be destined for internal consumption or export and does not focus on specific types of enterprises, thus also affecting very small ones – will now have to be discussed and approved by the European Union Parliament and Council to become an effective legislative act and will apply after twenty-four months from its entry into force. The Regulation Proposal of the European Commission appears to be wide-ranging, and doesn’t identify – at least in this first phase – specific product categories or certain producer countries, unlike what was decided by other countries (For example, the United States of America, in the framework of the bans on the import of goods made with forced labour, on 21 June 2022 adopted the Uyghur Forced Labor Prevention Act (UFLPA), which tightens the ban on imports into the USA for products made with forced labour in China, particularly in the Xinjiang Uyghur Autonomous Region). The most immediate effect of the desirable approval of the Proposal in question will be represented, for Union economic operators, by the need to carry out even more careful due diligence on supply chains and, more generally, on the reliability of their suppliers, in order to mitigate the risks of placing on the market products obtained by resorting to modern slavery.

•Liquid biopsy is a new non-invasive tool for the early detection of cancer.•Literature so far is promising for some kinds of cancer, but supported by a very low level of evidence.•New high-quality evidence is urgently needed.

Multiple factors can fuel nurses’ intention to leave their employing hospital or their profession. Job dissatisfaction and burnout are contributors to this decision. Sociodemographic and work context factors can also play a role in explaining nurses’ intention to leave.

The figure of the ‘Trust and Check Trader’ identified by the reform proposal of the Union Customs Code presented by the European Commission sets as basic requirements those of the current Authorised Economic Operator (AEO), providing, however, for a more transparent relationship between the former and the customs authorities, with the latter being able to access the information systems of this new category of trusted subjects, in exchange for a significant series of facilitations in customs operations. If the applicants for the new status are willing to submit to the necessary verifications and to allow access to their information systems, the draft Regulation provides for many advantages, some currently provided for AEOs and others introduced exclusively for Trust and Check Traders.

The figure of the ‘Trust and Check Trader’ identified by the reform proposal of the Union Customs Code presented by the European Commission sets as basic requirements those of the current Authorised Economic Operator (AEO), providing, however, for a more transparent relationship between the former and the customs authorities, with the latter being able to access the information systems of this new category of trusted subjects, in exchange for a significant series of facilitations in customs operations. If the applicants for the new status are willing to submit to the necessary verifications and to allow access to their information systems, the draft Regulation provides for many advantages, some currently provided for AEOs and others introduced exclusively for Trust and Check Traders.

The Court of Justice of the European Union, with the ruling of 12 May 2022 rendered in case C-714/20, affirmed two important principles: first of all, the Court held that Article 77 (3) of the Union Customs Code must be interpreted as meaning that, on the basis of that provision alone, the indirect customs representative is only liable for the duties due on goods which he has declared to customs, while not being also liable for the value added tax for import of the same goods; moreover, this representative, pursuant to Article 201 of the Council Directive 2006/112/EC - the European Community -, pertaining to the common system of value added tax, cannot be held liable for the payment of the value added tax on imports, jointly and severally with the importer, in the absence of national provisions that designate or recognize him or her, explicitly and unambiguously, as the payer of this tax. The legal question submitted to the Court of Justice has a long history. Already during the validity of the Community Customs Code, repealed from 1 May 2016, several customs administrations of the Member States of the European Union (including Italy) used to, in case of revision of the import customs declaration from which resulted in a greater duty and VAT (Value Added Tax) debt, notify an assessment notice both to the importer and to his/her indirect customs representative, jointly and severally, to recover both taxes. This is a consequence that derived, under the Community Code, from Article 201, paragraph 3, and, in the Union Code, from the express provision of Article 77, paragraph 3: both provisions, in identifying the figure of the debtor of the customs duties, state it is the ‘declarant’, while ‘In the event of indirect representation, the person on whose behalf the customs declaration is made shall also be a debtor’. However, this approach has been the subject of numerous disputes, fundamentally based on the consideration that the reference to Article 77 of the Union Customs Code (and, before that, Article 201 of the Community Customs Code) did not appear relevant to justify the recovery of VAT. The Court of Justice has now clarified the meaning of these provisions.

Circular no. 40 of 2021 of the Italian Customs Agency is important, as it addresses a significant problem for non-established economic operators who must carry out import operations into a Member State of the European Union, as it emphasizes the need to have a VAT (Value Added Tax) number and a tax representative who fulfils the formalities connected with the payment of the duties; from the customs point of view, this person is regarded as the importer and therefore able to provide all the information required for the procedure of release for free circulation and will be identified through the EORI (acronym for Economic Operator Registration and Identification) code that will be assigned to them by the customs authority at the time of the first relevant transaction. However, operators not established in the Union territory will be required, in order to be able to submit a customs declaration (in the specific case, of release for free circulation), to assign a mandate without representation to an established subject, in order for the latter to carry out this fulfilment, remaining jointly and severally obliged with its principal for the obligation deriving from the presentation of the declaration for the release for free circulation regime.

On 27 February, the European Commission and the United Kingdom reached a political agreement in principle on the so-called ‘Windsor Framework’, necessary to resolve several issues that had arisen between the parties, in particular with regard to the Northern Ireland issue, following the British withdrawal from the European Union. The joint solutions, found within the framework of the Withdrawal Agreement, are based on the following starting points: a comprehensive, cross-cutting and definitive solution, addressing practical difficulties in the operation of the Protocol; a balance between flexibilities for the movement of goods for end use in Northern Ireland and effective safeguards guaranteeing the protection of the EU’s Single Market; a clear distinction between goods at risk and goods not at risk of entering the EU’s Single Market. The European Commission and the Government of the United Kingdom will proceed, within the remit of their respective powers, with the necessary steps to translate the joint solutions into legally binding instruments.

On 9 September 2021, Regulation (EU) no. 821/2021, of the European Parliament and of the Council, of 20 May 2021, relating to the control of exports, brokering, technical assistance, transit and transfer of dual-use items, i.e., all those products, including software and technologies, which can be used for both civil and military purposes, came into effect. The new Regulation has as its main objective (see in particular ‘Whereas (5)’ in the preamble to the Regulation) that of making the common system for the control of exports of dual-use items even more effective, to ensure compliance with the commitments and responsibilities of the Member States and of the Union, particularly in the fields of non-proliferation, regional peace, security and stability and respect for human rights and international humanitarian law. For these purposes, the definitions of ‘dual-use products’ and ‘exporter’ have been expanded and, moreover, a specific Article (8) is dedicated to the issue of technical assistance, which in the previous Regulation (428/2009) was covered exclusively in certain explanatory notes in the Annexes. The changes in this Regulation also concern the authorizations for the export from the European Union of ‘dual-use’ goods: a whole new ‘large project authorization’ (Article 2 (14) of the Regulation) has been created, which consists of an individual export authorization or a global export authorization granted to one specific exporter for a type or category of dual-use items, which may be valid for exports to one or more specific end-users in one or more specified third countries for the purpose of a specified large-scale project. This permission can relate to intra-group technology transfers and cryptography. Also with regard to the procedures for the export of dual-use items, the European Union decided to make use of the ‘Internal Compliance Programmes’, already present in other legislative sectors of the Union.

The Union Customs Code (UCC) regulates the customs value of goods to be used for the purpose of the import declaration by identifying it with the ‘transaction value’, i.e., the price paid or payable for the goods when they are sold for export to the customs territory of the Union. To this calculation basis, in order to determine the amount of duties, additional elements must be added, such as transport costs to the Union border. The parties often resort to the delivery conditions codified in the ‘Incoterms’ published periodically by the International Chamber of Commerce of Paris, in order to clearly share the risks and responsibilities associated with transport. The UCC, however, does not cover the relationship between the customs value and the ‘Incoterms’, in particular in the case of returns of ‘Group D’ (for example: DAP – Delivered at place, or ‘delivered at the place of destination’), when the transport costs are borne by the transferor and not by the importing buyer: the Court of Justice, with the ruling of 22 April 2021, given in case C-75/20, Lifosa UAB, addressed the issue for the first time, clarifying that the relevant provisions of the code (in particular, Article 70, paragraph 1, and Article 71, paragraph 1, letter e, point i) must be interpreted as meaning that, in order to determine the customs value of imported goods, it is not necessary to add to their transaction value the costs actually incurred by the manufacturer for the transport of these goods to the place of their introduction into the customs territory of the European Union when, according to the agreed upon conditions of delivery, the obligation to cover these expenses is incumbent on the manufacturer, and this even if said expenses exceed the price actually paid by the importer, when this price corresponds to the real value of said goods.

Our study aimed to develop and validate a real-time crowding composite scale for pediatric emergency department (PED). The study took place in one teaching PED for 2 months. The outcome was the perception of crowding evaluated by triage nurses and pediatricians on a 10-level Likert scale. Triage nurses evaluated crowding at each moment of a child's admission and pediatrician at each moment of a child's discharge. The outcome was the hourly mean of all evaluations of crowding (hourly crowding perception). For analysis, originally, we only selected hours during which more than 2 nurses and more than 2 pediatricians evaluated crowding and, moreover, during which evaluations were the most consensual. As predictors, we used hourly means of 10 objective crowding indicators previously selected as consensual in a published French national Delphi study and collected automatically in our software system. The model (SOTU-PED) was developed over a 1-month data set using a backward multivariable linear regression model. Then, we applied the SOTU-PED model on a 1-month validation data set. During the study period, 7341 children were admitted in the PED. The outcome was available for 1352/1392 hours, among which 639 were included in the analysis as “consensual hours.” Five indicators were included in the final model, the SOTU-PED (R2= 0.718). On the validation data set, the correlation between the outcome (perception of crowding) and the SOTU-PED was 0.824. To predict crowded hours (hourly crowding perception >5), the area under the curve was 0.957 (0.933–0.980). The positive and negative likelihood ratios were 8.16 (3.82–17.43) and 0.153 (0.111–0.223), respectively. Using a simple model, it is possible to estimate in real time how crowded a PED is.

On 15 March 2021, a new import control system for the European Union was launched, called Import Control System 2 (or ICS2): it will guarantee a more efficient and effective import control activity and facilitate communications between economic operators and customs administrations of Member States. However, a gradual adaptation of the information systems will be necessary and, further, different procedures, especially for postal operators and express carriers, who are the first to deal with the new system, will be needed. There are three versions of the new system, the first just entered into effect and the others to be implemented by 2024: Release 1 requires postal operators and express carriers to submit a subset of their Entry Summary Declaration data, for goods transported by air only; Release 2 will require all air carriers, for all goods transported by air, to integrate the subset of data with the other information required for the complete Entry Summary Declaration; Release 3 requires specific functions to submit the complete Entry Summary Declaration for all goods carried by means of transport other than air, and therefore will concern maritime, rail and road operators as well as certain importers and recipients of the goods in the European Union.

The European Union and the United Kingdom have reached a last-minute broad agreement on their future relations. In the field of trade and customs operations, rules have been defined to facilitate trade in goods, with the provision of total exemption from import duties for goods originating in one of the two Parties on the basis of rules which, for their characteristics, appear to favour products entirely manufactured in the territory of the Union or of the United Kingdom, albeit with some tolerances. Both for the purposes of proving the requirement of preferential origin and in carrying out customs operations, the Agreement follows a very clear line, simplifying obligations for the economic operators, with the aim of keeping the volume of commercial traffic unchanged, as developed over forty-seven years of union under the European flag.

The European Union and Vietnam have signed a far-reaching Free Trade Agreement, which came into force on 1 August 2020 and represents a turning point in the trade relations that the Union has with third countries.In addition to providing for a substantial reduction in duties, partly with immediate effect and partly over the next few years, the agreement affects non-tariff barriers, substantially simplifying the documentation needed for customs operations (in particular in Vietnam) and the certifications required for certain types of products (for example, for pharmaceuticals). The Agreement also limits the adoption of anti-dumping and countervailing duties, specifying that trade remedies should be enforced in full compliance with the relevant requirements of the World Trade Organization and should be based on a fair and transparent system. The products originating from the two contracting parties will benefit from the duty exemptions and reductions upon production of a proof of preferential origin, represented, up to a value of 6,000 euros, by the exporter’s invoice declaration and, above this amount, by an exporter registered on the REX (Registered EXporter) system. The protection of intellectual property, ‘Made in’ and geographical indications is ensured, with specific provisions aimed at preventing fraud. Along with the Free Trade Agreement, the Union and Vietnam have also signed an Investment Protection Agreement, whose main point is the provision for the creation of an independent and qualified court to settle disputes between investing companies and the state.

Three Kentish laws (Æthelberht 9, Hloþære and Eadric 8 and 9) written in the 7th century mention the places where the men drink (þær mæn drincen).It has already been observed that drinking is not only a feature of a male warrior society, but represents a quasi-juridical institution which enjoys special protection (Renato Gendre 1992). However, the offences committed during these gatherings and the high fines duly paid can only partly be attributed to a general violation of the king’s and house protection.Behind these laws there is an echo of more specific rituals. The legal character in drinking together, as it emerges in the symbolic offences described and fined in Hloþære and Eadric 8 and 9, has never been explored in the light of the recent works on ritual. The meaning of drinking (and toasting) as a binding moment inside some legal proceedings as well as its specific relation to consent are subject of the following investigation. As the most recent works on ritual show, the binding aspect and the creation of consent are among the major features of ritual. Only inside this discourse can thus be explained the meaning in the act of taking a cup from another where men are drinking (with no fault of the man from whom the cup was taken) and of drawing a weapon without doing any harm. These are two actions in which a boasting character is only an aspect, a superficial feature of a warrior society. The deep legal symbolism of both acts deserves further exploration, in which they prevent the participation of the concerned in a legal ceremony and disturb the building of the consensus.

Mutations in TBC1D24are described in patients with a spectrum of neurological diseases, including mild and severe epilepsies and complex syndromic phenotypes such as Deafness, Onycodystrophy, Osteodystrophy, Mental Retardation and Seizure (DOORS) syndrome. The product of TBC1D24is a multifunctional protein involved in neuronal development, regulation of synaptic vesicle trafficking, and protection from oxidative stress. Although pathogenic mutations in TBC1D24span the entire coding sequence, no clear genotype/phenotype correlations have emerged. However most patients bearing predicted loss of function mutations exhibit a severe neurodevelopmental disorder. Aim of the study is to investigate the impact of TBC1D24 knockdown during the first stages of neuronal differentiation when axonal specification and outgrowth take place. In rat cortical primary neurons silenced for TBC1D24, we found defects in axonal specification, the maturation of axonal initial segment and action potential firing. The axonal phenotype was accompanied by an impairment of endocytosis at the growth cone and an altered activation of the TBC1D24 molecular partner ADP ribosylation factor 6. Accordingly, acute knockdown of TBC1D24 in cerebrocortical neurons in vivo analogously impairs callosal projections. The axonal defect was also investigated in human induced pluripotent stem cell-derived neurons from patients carrying TBC1D24mutations. Reprogrammed neurons from a patient with severe developmental encephalopathy show significant axon formation defect that were absent from reprogrammed neurons of a patient with mild early onset epilepsy. Our data reveal that alterations of membrane trafficking at the growth cone induced by TBC1D24 loss of function cause axonal and excitability defects. The axonal phenotype correlates with the disease severity and highlight an important role for TBC1D24 in connectivity during brain development.

Context. The COSMOS survey is a multiwavelength survey aimed to study the evolution of galaxies, AGN and large scale structures. Within this survey XMM-COSMOS a powerful tool to detect AGN and galaxy clusters. The XMM-COSMOS is a deep X-ray survey over the full 2 deg2of the COSMOS area. It consists of 55 XMM-Newtonpointings for a total exposure of ~1.5 Ms with an average vignetting-corrected depth of 40 ks across the field of view and a sky coverage of 2.13 deg2.

New research on Anglo-Saxon law. The article reviews five works connected to Anglo-Saxon legislation in different fields of research. The material for Volume II of Wormald’s opus magnum existed in various stages of development when Wormald died in 2004 and it is a miscellaneous collection of papers and lectures, partly delivered at the University of Oxford by the author. Roach is connected to the teachings of Wormald as a historian of kingship; challenging old models, Roach focuses with comparative eyes on the role of assemblies in Anglo-Saxon England as an essential feature of kingship. An „unaccustomed point of view“ on early English law is also held by Jurasinki/Falk who offer the 1stcomplete edition of Theodor’s canons and by Jurasinski’s work on those penitentials which gave advice on matters of secular law. In doing this he discovers not only that the scribes who translated them from Latin recasted them into new rules intended to better suit the needs of English laypeople, but also how wrong it is to assume that only kings participated in the creation of Anglo-Saxon legal culture. A review of works on early English legislation cannot avoid the question of language of the legal sources. They were mostly written in the Anglo-Saxon vernacular rather than in Latin like the continental leges. Hough brings together historical and linguistic evidence and explores various aspects of the legal system of Anglo-Saxon England, focusing particularly on the interpretation of laws on the position of women in society.

Infiltration of immune cells and chronic inflammation substantially affect skeletal and cardiac muscle degeneration in Duchenne muscular dystrophy. In the immune system, extracellular adenosine triphosphate (ATP) released by dying cells is sensed as a danger associated molecular pattern through P2 purinergic receptors. Specifically, the P2X7 subtype has a prominent role in regulating immune system physiology and contributes to inflammasome activation also in muscle cells. Here, we show that in vivoblockade of the extracellular ATP/P2X purinergic signaling pathway by periodate-oxidized ATP delayed the progression of the dystrophic phenotype and dampened the local inflammatory response in mdxmice, a spontaneous mouse model of dystrophin deficiency. Reduced infiltration of leukocytes and macrophages and decreased expression of IL-6 were revealed in the muscles of periodate-oxidized ATP-treated mdxmice. Concomitantly, an increase in Foxp3+immunosuppressive regulatory T cells was observed and correlated with enhanced myofiber regeneration. Moreover, we detected reduced concentrations of profibrotic cytokines, including transforming growth factor-β and connective tissue growth factor, in muscles of periodate-oxidized ATP-treated mdxmice. The improvement of inflammatory features was associated with increased strength and reduced necrosis, thus suggesting that pharmacologic purinergic antagonism altering the adaptive immune component in the muscle infiltrates might represent a promising therapeutic approach in Duchenne muscular dystrophy.

Context. The COSMOS survey is a multiwavelength survey aimed to study the evolution of galaxies, AGN and large scale structures. Within this survey XMM-COSMOS?a powerful tool to detect AGN and galaxy clusters. The XMM-COSMOS?is a deep X-ray survey over the full 2?deg2of the COSMOS area. It consists of 55?XMM-Newton? pointings for a total exposure of ~1.5?Ms with an average vignetting-corrected depth of 40?ks across the field of view and a sky coverage of 2.13?deg2.Aims. We present the catalogue of point-like X-ray sources detected with the EPIC?CCD cameras, the logN - logS relations and the X-ray colour?colour diagrams.Methods. The analysis was performed using the XMM-SAS data analysis package in the 0.5?2?keV, 2?10?keV and 5?10?keV energy bands. Source detection has been performed using a maximum likelihood technique especially designed for raster scan surveys. The completeness of the catalogue as well as logN -logS and source density maps have been calibrated using Monte Carlo simulations.Results. The catalogs contains a total of 1887?unique sources detected in at least one band with likelihood parameter det_ml?>10. The survey, which shows unprecedented homogeneity, has a flux limit of ~1.7?10 -15erg?cm-2?s-1, ~9.3 ?10 -15erg?cm-2?s-1? and ~1.3 ?10-14erg?cm-2?s-1? over 90% of the area (1.92?deg2) in the 0.5?2?keV, 2?10?keV and 5?10?keV energy band, respectively. Thanks to the rather homogeneous exposure over a large area, the derived logN - logS relations are very well determined over the flux range sampled by XMM-COSMOS. These relations have been compared with XRB synthesis models, which reproduce the observations with an agreement of ~10% in the 5?10?keV and 2?10?keV band, while in the 0.5?2?keV band the agreement is of the order of ~20%. The hard X-ray colors confirmed that the majority of the extragalactic sources in a bright subsample are actually type?I or type?II AGN. About?20% of the sources have a X-ray luminosity typical of AGN (LX> 1042?erg/s) although they do not show any clear signature of nuclear activity in the optical spectrum.

This paper presents new Chandra and BeppoSAX observations aimed at investigating the optical-X-ray mismatch in the enigmatic class of the composite galaxies discovered by a cross-correlation of IRAS and ROSAT all-sky survey catalogs. These galaxies have been classified as star-forming objects on the basis of their optical spectra, while the detection of weak broad wings in the Ha emission in a few of them and their high X-ray luminosity in the ROSAT band indicated the presence of an active nucleus. The analysis of Chandra observations for four composite galaxies has revealed nuclear pointlike sources, with a typical AGN spectrum (G ~ 1.7-1.9) and little intrinsic absorption. A strong flux variability has been observed on different timescales; in particular, most of the sources were brighter at the ROSAT epoch. Although it is of relatively low luminosity for the AGN class (L2-10 keV ~ 3-60 x 1041 ergs s-1), the active nucleus is nevertheless dominant in the X-ray domain. At other wavelengths it appears to be overwhelmed by the starburst and/or host galaxy light, yielding the composite classification for these objects.

We present the first [?]3.5 (conservative) or [?]5.8 s (sum-of-lines significance) detection of two warm-hot intergalactic medium (WHIM) filaments at z > 0, which we find along the line of sight to the blazar Mrk 421. These systems are detected through highly ionized resonant metal absorption in high-quality Chandra ACIS and HRC Low Energy Transmission Grating (LETG) spectra of Mrk 421, obtained following our two Target of Opportunity requests during two outburst phases (F0.5-2 keV = 40 and 60 mcrab; 1 crab = 2 x 10-8 ergs s-1 cm-2). Columns of He-like oxygen and H-like nitrogen can be detected in the co-added LETG spectrum of Mrk 421 down to a sensitivity of Nimg1.gif [?] 8 x 1014 cm-2 and Nimg2.gif [?] 1015 cm-2, respectively, at a significance [?]3 s. The two intervening WHIM systems that we detect have O VII and N VII columns of Nimg1.gif = (1.0 +- 0.3) x 1015 cm-2, Nimg3.gif = (0.8 +- 0.4) x 1015 cm-2 and Nimg1.gif = (0.7 +- 0.3) x 1015 cm-2, Nimg2.gif = (1.4 +- 0.5) x 1015 cm-2, respectively. We identify the closest of these two systems with an intervening WHIM filament at cz = 3300 +- 300 km s-1. The second system, instead, at cz = 8090 +- 300 km s-1, is identified with an intervening WHIM filament located ~13 Mpc from the blazar. The filament at cz = 3300 +- 300 lies [?]5 Mpc from a known H I Lya system at cz = 3046 +- 12 km s-1 (Shull and coworkers) whose 3 s maximal H I kinetic temperature, as derived from the observed line FWHM, is T [?] 1.2 x 105 K. This temperature is inconsistent with the temperature measured for the X-ray filament, so if the systems are related, a multiphase WHIM is required. Combining UV and far-ultraviolet (FUV) upper limits on the H I Lya and the O VI2s-2p transitions with our measurements in the X-rays, we show that, for both filaments, equilibrium collisional ionization (with residual photoionization by both the diffuse UV and X-ray background and the beamed emission of Mrk 421 along our line of sight) provides acceptable solutions. These solutions define ranges of temperatures, metallicity ratios, and equivalent H column densities, which are in good agreement with the predictions of hydrodynamical simulations for the formation of large-scale structures in the universe. From the detected number of WHIM filaments along this line of sight we can estimate the number of O VII filaments per unit redshift with columns larger than 7 x 1014 cm-2, d[?] img1.gif/dz(Nimg1.gif [?] 7 x 1014) = 67img4.gif, consistent, within the large 1 s errors, with the hydrodynamical simulation predictions of d[?] img1.gif/dz(Nimg1.gif [?] 7 x 1014) = 30. Finally, we measure a cosmological mass density of X-ray WHIM filaments Ob = 0.027img5.gif x 10img6.gif, consistent with both model predictions and the estimated number of "missing" baryons at low redshift.

We report monitoring of the 0.3-10 keV spectrum of NGC 4258 with the XMM-Newton Observatory at five epochs over 1.5 yr. We also report reprocessing of an overlapping four-epoch series of archival Chandra observations (0.5-10 keV). By including earlier ASCA and BeppoSAX observations, we present a new, 9 year time series of models fitted to the X-ray spectrum of NGC 4258. We model the Chandra and XMM-Newton data self-consistently with partially absorbed, hard power-law, soft thermal plasma, and soft power-law components. Over the 9 years, the photoelectric absorbing column (~1023 cm-2) did not vary detectably, except for a ~40% drop between two ASCA epochs separated by 3 years (in 1993 and 1996) and a ~60% rise between two XMM-Newton epochs separated by just 5 months (in 2001 and 2002). In contrast, factor of 2-3 changes are seen in absorbed flux on the timescale of years. These are uncorrelated with changes in absorbing column and indicative of central engine variability. The most rapid change in luminosity (5-10 keV) that we detect (with XMM-Newton and Chandra) is ~30% over 19 days. The warped disk, a known source of H2O maser emission in NGC 4258, is believed to cross the line of sight to the central engine. We propose that the variations in absorbing column arise from inhomogeneities sweeping across the line of sight in the rotating disk at the radius at which the disk crosses the line of sight. We estimate that the inhomogeneities are ~1015 cm in size at the crossing radius of 0.29 pc, slightly smaller than the expected scale height of the disk. This result thus provides strong evidence that the warped accretion disk is the absorber in this (and possibly other) active galactic nuclei (AGNs). This is the first direct confirmation that obscuration in type 2 AGNs may, in some cases, arise in thin, warped accretion disks rather than in geometrically thick tori. Some previous studies report detection of weak Fe Ka emission in NGC 4258. We do not detect this line emission in any of our XMM-Newton spectra with a 90% upper limit to the equivalent width of ~49 eV for one observation. Weak, time-variable Fe line absorption has also been reported for a previous Chandra study. We do not observe evidence of absorption lines in the XMM-Newton or reprocessed Chandra data. The absence of Fe line emission is consistent with the disk being optically thin to hard photons, as well as subtending a small solid angle as seen from the central engine because of the known shallowness of the warp.

We report the results from a Chandra target-of-opportunity observation of the low-luminosity narrow-line Seyfert 1 galaxy NGC 4051, obtained during a 6 week duration low-flux state in 2001 February. During the Chandra observation, the 2-10 keV source flux was 7 x 10-12 ergs cm-2 s-1, corresponding to a 2-10 keV luminosity of ~8 x 1040 ergs s-1. We confirm the absence of strong extended soft X-ray emission in NGC 4051 and that the low-state spectrum is dominated by the central point source. The X-ray spectrum has an unusual, hybrid shape, very soft below ~3 keV (and which we model with a blackbody of temperature of 0.14 keV) and very hard at higher energies (power-law slope of G ~ 1). The light curves in both soft and hard bands are significantly variable and correlated, implying a connection between hard and soft components and proving that the hard component is dominated by primary continuum emission and is not due to pure reflection from distant cold material. However, a comparison with RXTE data obtained during the same 2001 low state suggests the presence of unusually prominent disk reflection features, which may help to explain the apparent upward curvature and extreme hardness of the Chandra spectrum above a few keV. The shape of the 2001 low-state spectrum is consistent with that observed in a brief (<3 days) low-flux excursion during the source's normal state in 2000 April, suggesting that emission processes during the low state are not significantly different to those in the normal state. The unusual spectral shape observed in the low state may be a continuation to low fluxes of the normal, flux-dependent spectral variability of the source.

We present the first X-ray detection of resonant absorption from warm/hot local gas either in our Galaxy, or in the intergalactic space surrounding our Galaxy, along the line of sight toward the blazar PKS 2155-304. The Chandra HRCS/LETG spectrum of this z = 0.116 source clearly shows, at [?]5 s level, unresolved (FWHM [?] 800 km s-1 at a 2 s confidence level) O VII Ka and Ne IX Ka resonant absorption lines at 21.603img1.gif and 13.448img2.gif A (i.e., cz = 14img3.gif km s-1 in the rest frame, from the O VII Ka line). O VIII Ka and O VII Kb from the same system are also detected at a lower significance level (i.e., ~3 s), while upper limits are set on O VIII Kb, Ne X Ka, and Ne IX Kb. The Far Ultraviolet Spectroscopic Explorer spectrum of this source shows complex O VI 2s-2p absorption at the same redshift as the X-ray system, made by at least two components: one relatively narrow (FWHM = 106 +- 9 km s-1) and slightly redshifted (cz = 36 +- 6 km s-1), and one broader (FWHM = 158 +- 26 km s-1) and blueshifted (cz = -135 +- 14 km s-1). We demonstrate that the physical states of the UV and X-ray absorbers are hard to reconcile with a single, purely collisionally ionized, equilibrium plasma. We propose instead that the X-ray and at least the broader and blueshifted UV absorber are produced in a low-density intergalactic plasma, collapsing toward our Galaxy, consistent with the predictions of a warm-hot intergalactic medium from numerical simulations. We find that any reasonable solution requires overabundance of Ne compared to O by a factor of ~2, with respect to the solar value. We propose several scenarios to account for this observation.

Deep Chandra Low Energy Transmission Grating and High Resolution Camera spectroscopic observations of the isolated neutron star candidate RX J1856.5-3754 have been analyzed to search for metallic and resonance cyclotron spectral features and for pulsation behavior. As found from earlier observations, the X-ray spectrum is well represented by an ~60 eV (7 x 105 K) blackbody. No unequivocal evidence of spectral line or edge features has been found, arguing against metal-dominated models. The data contain no evidence for pulsation, and we place a 99% confidence upper limit of 2.7% on the unaccelerated pulse fraction over a wide frequency range from 10-4 to 100 Hz. We argue that the derived interstellar medium neutral hydrogen column density of 8 x 1019 cm-2 [?] NH [?] 1.1 x 1020 cm-2 favors the larger distance from two recent Hubble Space Telescope parallax analyses, placing RX J1856.5-3754 at ~140 pc instead of ~60 pc and in the outskirts of the R CrA dark molecular cloud. That such a comparatively rare region of high interstellar matter (ISM) density is precisely where an isolated neutron star reheated by accretion of ISM would be expected is either entirely coincidental or current theoretical arguments excluding this scenario for RX J1856.5-3754 are premature. Taken at face value, the combined observational evidence--a lack of spectral and temporal features and an implied radius of R[?] = 3.8-8.2 km that is too small for current neutron star models--points to a more compact object, such as allowed for quark matter equations of state.

We present results from a ChandraX-Ray Observatorystudy of the field X-ray source populations in four different observations: two high-redshift (z~ 0.5) clusters of galaxies 3C 295 and RX J003033.2+261819; and two noncluster fields with similar exposure time. Surprisingly, the 0.5-2 keV source surface densities (~900-1200 sources deg-2at a flux limit of 1.5 × 10-15ergs cm-2s-1) measured in an ~8' × 8' area surrounding each cluster exceed by a factor of ~2 the value expected on the basis of the ROSATand Chandralog N- log S, with a significance of ~2 ? each, or ~3.5 ? when the two fields are combined (i.e., a probability to be a statistical fluctuation of <1% and <0.04%, respectively). The same analysis performed on the noncluster fields and on the outer chips of the cluster fields does notshow evidence of such an excess. In both cluster fields, the summed 0.5-10 keV spectrum of the detected objects is well fitted by a power law with ? ~ 1.7 similar to active galactic nuclei (AGNs) and shows no sign of intrinsic absorption. The few (~10 of 35) optical identifications available to date confirm that most of them are, as expected, AGNs, but the number of redshifts available is too small to allow conclusions on their nature. We discuss possible interpretations of the overdensity in terms of a statistical variation of cosmic background sources; a concentration of AGNs and/or powerful starburst galaxies associated with the clusters; and gravitational lensing of background QSOs by the galaxy clusters. All explanations, however, are difficult to reconcile with the large number of excess sources detected. Deeper X-ray observations and more redshifts measurements are clearly required to settle the issue.

A previously healthy 6-month-old Asian girl presented to the emergency department (ED) after 7 to 10 days of fever of 101 to 102°F, cough, and intermittent vomiting. Pneumonia was diagnosed and successfully treated, and the patient was discharged. She returned to the ED after her mother noticed mild facial asymmetry, left upper extremity weakness, and an episode of jerkiness. The mother then revealed that both she and the child's maternal grandmother, who also lived with the patient, had suffered chronic coughs in recent months. The mother's previous chest radiograph showed pulmonary tuberculosis. The patient's magnetic resonance imaging findings were consistent with a cerebrovascular event. Positive results on cerebrospinal fluid analysis, the mother's suspicious tuberculosis-like history, and the patient's clinical symptoms pointed heavily toward a diagnosis of tuberculous meningitis. A 4-drug antituberculosis regimen with dexamethasone was instituted and scheduled to continue for 12 months. However, the patient returned to the ED 2 months later after developing an obstructive hydrocephalus.

On 1998 May 9–11, BeppoSAXobserved the low‐luminosity Seyfert 1 galaxy NGC 4051 in an ultra‐dim X‐ray state. The 2–10 keV flux (1.26 × 10−12erg cm−2s−1) was about 20 times fainter than its historical average value, and remained steady along the whole observation (∼2.3 d). The observed flat spectrum (Γ ≃ 0.8) and intense iron line (EW ≃ 600 eV) are best explained by assuming that the active nucleus has switched off, leaving only a residual reflection component visible.

We report on the analysis of a deep ExtremeUltravioletExplorer(EUVE) observation made with the Deep Survey and Spectrometer telescope, which included in the field the remarkable bright extreme ultraviolet (EUV) transient source RE J1255+266, discovered in 1994 June by the ROSATWide Field Camera (WFC). A careful analysis of the resulting Deep Survey (DS) Lexan/B (67-178 Å) image, whose aggregated exposure time is 137 ks, has not revealed any trace of the source but has yielded a quite stringent formal upper limit on the quiescent EUVEDS count rate of 0.003 counts s-1(3 ?) and a "visual" upper limit of 0.002 counts s-1. An analysis based on blackbody spectra, pure hydrogen DA white dwarf models, and optically thin plasma model spectra has provided constraints on the source counterpart. The observed count rate upper limit is consistent with the optical identification proposed by Watson et al. in which a DA white dwarf is the primary component of a CV-like system involving a very low mass M dwarf secondary star. Our upper limit to the EUVEDS count rate, when compared with the count rate observed with the ROSATWFC at the peak of the outburst, implies a brightening of the EUV source flux relative to quiescence by a factor of greater than 54,000.

We report on the analysis of a deep Extreme Ultraviolet Explorer (EUVE) observation made with the Deep Survey and Spectrometer telescope, which included in the field the remarkable bright extreme ultraviolet (EUV) transient source RE J1255+266, discovered in 1994 June by the ROSAT Wide Field Camera (WFC). A careful analysis of the resulting Deep Survey (DS) Lexan/B (67-178 A) image, whose aggregated exposure time is 137 ks, has not revealed any trace of the source but has yielded a quite stringent formal upper limit on the quiescent EUVE DS count rate of 0.003 counts s-1 (3 s) and a "visual" upper limit of 0.002 counts s-1. An analysis based on blackbody spectra, pure hydrogen DA white dwarf models, and optically thin plasma model spectra has provided constraints on the source counterpart. The observed count rate upper limit is consistent with the optical identification proposed by Watson et al. in which a DA white dwarf is the primary component of a CV-like system involving a very low mass M dwarf secondary star. Our upper limit to the EUVE DS count rate, when compared with the count rate observed with the ROSAT WFC at the peak of the outburst, implies a brightening of the EUV source flux relative to quiescence by a factor of greater than 54,000.