Minimal Extent Research Articles

Ultralong-Chain-Spaced Crystalline Poly(H-phosphonate)s and Poly(phenylphosphonate)s

Aliphatic poly(H-phosphonate)s were obtained by polyesterification of dimethyl H-phosphonate with bio-based long-chain diols. Nonadecane-1,19-diol, tricosane-1,23-diol, and octatetracontane-1,48-diol with dimethyl H-phosphonate yield the corresponding polyphosphoesters (PPE19H, PPE23H, and PPE48H) with molecular weights (Mn) up to 4.3 × 104 g mol–1. Postfunctionalization of these polymers via Hirao cross-coupling yields the selectively functionalized poly(H-phosphonate)s PPE19Ph, PPE23Ph, and PPE48Ph. DSC analysis revealed significantly enhanced crystallinities and melting points (up to Tm = 110 °C) with increasing methylene sequence lengths. Hydrolytic degradation of polymer powder of poly-(H-phosphonate) occurred up to 95% in 2 days. The degradation rates decreased with increasing methylene sequence length. After postfunctionalization, degradation occurred only to a minimal extent over 3 months in basic and in acidic media.

Super Turbocharging the Direct Injection Diesel engine

Abstract The steady operation of a turbocharged diesel direct injection (TDI) engine featuring a variable speed ratio mechanism linking the turbocharger shaft to the crankshaft is modelled in the present study. Key parameters of the variable speed ratio mechanism are range of speed ratios, efficiency and inertia, in addition to the ability to control relative speed and flow of power. The device receives energy from, or delivers energy to, the crankshaft or the turbocharger. In addition to the pistons of the internal combustion engine (ICE), also the turbocharger thus contributes to the total mechanical power output of the engine. The energy supply from the crankshaft is mostly needed during sharp accelerations to avoid turbo-lag, and to boost torque at low speeds. At low speeds, the maximum torque is drastically improved, radically expanding the load range. Additionally, moving closer to the points of operation of a balanced turbocharger, it is also possible to improve both the efficiency η, defined as the ratio of the piston crankshaft power to the fuel flow power, and the total efficiency η*, defined as the ratio of piston crankshaft power augmented of the power from the turbocharger shaft to the fuel flow power, even if of a minimal extent. The energy supply to the crankshaft is possible mostly at high speeds and high loads, where otherwise the turbine could have been waste gated, and during decelerations. The use of the energy at the turbine otherwise waste gated translates in improvements of the total fuel conversion efficiency η* more than the efficiency η. Much smaller improvements are obtained for the maximum torque, yet again moving closer to the points of operation of a balanced turbocharger. Adopting a much larger turbocharger (target displacement x speed 30% larger than a conventional turbocharger), better torque outputs and fuel conversion efficiencies η* and η are possible at every speed vs. the engine with a smaller, balanced turbocharger. This result motivates further studies of the mechanism that may considerably benefit traditional powertrains based on diesel engines.

The Challenge of Amoralism

AbstractAccording to unconditional motivational internalism, there is an a priori constraint on an agent's forming a sincere moral judgement, namely that she is, at least to some minimal extent, motivated to act as it dictates. In order to undermine this internalist position, proponents of motivational externalism typically appeal to the possibility of the amoralist—i.e. an individual who makes sincere moral judgements, but who is completely unmoved to act accordingly. This strategy is known as the challenge of amoralism. Against this strategy, I will argue that in order to represent a genuine case of amoralism, and a credible counterexample to unconditional motivational internalism, an agent would have to simultaneously satisfy an epistemically inconsistent set of conditions. Thus, the conclusion I will attempt to defend in this paper is that the challenge of amoralism does not succeed in posing a legitimate threat to unconditional motivational internalism.

Notch1 suppresses prostate cancer cell invasion via the metastasis-associated 1-KiSS-1 metastasis-suppressor pathway.

Notch1 is a type-1 transmembrane receptor which has been demonstrated to be involved in proliferation in various organisms. A number of studies have proposed that Notch signaling may be aberrantly activated, thus contributing to development, invasion and metastasis in a variety of human cancers. In the present study, the function and mechanism of Notch1 in human prostate cancer (PCa) LNCaP cells in vitro was investigated. Notch1 and cleaved-Notch1 expression were evaluated in human PCa cell lines, including LNCaP, PC-3 and DU 145, and the human prostate epithelial RWPE-1 cell line. LNCaP cells were transfected with Notch1-targeting short hairpin RNAs (shRNAs) and the level of proliferation, the ability to invade and the expression of genes associated with cancer cell invasion were subsequently investigated. Notch1 was highly expressed in LNCaP, PC-3 and DU 145 cells compared with RWPE-1 cells, while cleaved-Notch1 was expressed in LNCaP, PC-3 and DU 145 cells, and only to a minimal extent in RWPE-1 cells. Knockdown of Notch1 by shRNA in LNCaP cells markedly decreased cell invasion through Matrigel and inhibited cell proliferation 48 h following transfection. Reverse transcription-quantitative polymerase chain reaction analysis indicated that Notch1-knockdown resulted in a significant reduction of metastasis-associated 1 (MTA1) and increase of KiSS-1 metastasis-suppressor (KISS-1), mitogen-activated protein kinase 4 (MKK4) and cluster of differentiation 82 (KAI1). The present data demonstrated that expression of Notch1 was significantly associated with the invasion of prostate cancer. Knockdown of Notch1 decreased the invasive ability of LNCaP cells, which may be caused by downregulating MTA1 and upregulating KISS-1, MKK4 and KAI1. These findings indicated that targeting Notch1 may provide a novel method of suppressing or treating metastasis in prostate cancer.

Therapists’ self-reported chronic strategies of disconnection in everyday life and in counselling and psychotherapy: an exploratory study

ABSTRACTThe aim of this study was to explore how therapists believe they may relationally disconnect from other people and their clients, with an overall objective of developing methods for enhancing relational depth in counselling and psychotherapy. Participants were 168 trainee and practicing therapists, who listed their chronic strategies of disconnections (CSoDs) in everyday relationships, and then rated the presence of these CSoDs in their therapeutic work. Thirty-nine categories of self-reported everyday CSoDs emerged, organised into seven domains. Most prevalent were behavioural, passive and intrapsychic strategies. Over half of the CSoDs were rated as being present in therapy to a minimal extent, most commonly passive CSoDs, disingenuous CSoDs and humour. Male therapists, and trainee therapists, were most likely to identify their CSoDs as present in therapy.

Role for Atlantic inflows and sea ice loss on shifting phytoplankton blooms in the Barents Sea

AbstractPhytoplankton blooms in the Barents Sea are highly sensitive to seasonal and interannual changes in sea ice extent, water mass distribution, and oceanic fronts. With the ongoing increase of Atlantic Water inflows, we expect an impact on these blooms. Here, we use a state‐of‐the‐art collection of in situ hydrogeochemical data for the period 1998–2014, which includes ocean color satellite‐derived proxies for the biomass of calcifying and noncalcifying phytoplankton. Over the last 17 years, sea ice extent anomalies were evidenced having direct consequences for the spatial extent of spring blooms in the Barents Sea. In years of minimal sea ice extent, two spatially distinct blooms were clearly observed: one along the ice edge and another in ice‐free water. These blooms are thought to be triggered by different stratification mechanisms: heating of the surface layers in ice‐free waters and melting of the sea ice along the ice edge. In years of maximal sea ice extent, no such spatial delimitation was observed. The spring bloom generally ended in June when nutrients in the surface layer were depleted. This was followed by a stratified and oligotrophic summer period. A coccolithophore bloom generally developed in August, but was confined only to Atlantic Waters. In these same waters, a late summer bloom of noncalcifying algae was observed in September, triggered by enhanced mixing, which replenishes surface waters with nutrients. Altogether, the 17 year time‐series revealed a northward and eastward shift of the spring and summer phytoplankton blooms.

Paleogeographic and structural evolution of northwestern Africa and its Atlantic margins since the early Mesozoic

The geological evolution of northwestern Africa and its continental margins is investigated in the light of nine Meso-Cenozoic paleogeological maps, which integrate original minimal extent of sedimentary deposits beyond their present-day erosional limits. Mapping is based on a compilation of published original data on the stratigraphy and depositional environments of sediments, structures, magmatism, and low-temperature thermochonology, as well as on the interpretation of industrial seismic and borehole data. We show that rifting of the equatorial domain propagated eastward from the Central Atlantic between the Valanginian (ca. 140 Ma) and the Aptian (ca. 112 Ma) as an en echelon strike-slip and rift system connected to an inland rift network. This network defines a six-microplate synrift kinematic model for the African continental domain. We document persistent, long-wavelength eroding marginal upwarps that supplied clastic sediments to the offshore margin basins and a large intracratonic basin. The latter acted as a transient sediment reservoir because the products of its erosion were transferred both to the Tethys (to the north) and the Atlantic Ocean. This paired marginal upwarp-intra­cratonic basin source-to-sink system was perturbed by the growth of the late Paleogene Hoggar hotspot swell that fragmented the intracratonic basins into five residual depocenters. By linking the evolution of the continental margins to that of their African hinterland, this study bears important implications for the interplay of long-wavelength deformation and sediment transfers over paired shield-continental margin systems.

‘Metall auf Metall’ – the German Federal Constitutional Court discusses the permissibility of sampling music tracks

The German Federal Constitutional Court has delivered an important decision with regards to the permissibility of sampling which is widely used in hip hop and electronic music. With this decision, the Court ended a dispute that has been ongoing for almost twenty years. Furthermore, the Court has applied a fundamental rights discourse between the countervailing rights of the original authors and those of the new works using samples from the original works. The preceding courts found that sampling would constitute an infringement of the phonogram producer rights (Section 85 of the German Author's Rights Act) where the samples could have been created independently. The German Constitutional Court, however, disagreed: by holding that sampling was a form of art protected by the fundamental right of artistic freedom and may outweigh the exploitation interest of the phonogram producer, which would only be impaired to a minimal extent by sampling.

Dengue Virus Entry and Replication Does Not Lead to Productive Infection in Platelets.

Thrombocytopenia is a characteristic feature during the acute phase of dengue infection and has been found to associate with vascular leakage in severe dengue. Although dengue antigens have been observed in platelets, there is no strong evidence to suggest a direct infection of platelets by dengue virus as a contributing factor for thrombocytopenia. We show that dengue virus can enter platelets but replicate viral ribonucleic acid to a minimal extent and, therefore, cannot produce infectious virus. Dengue antigen was undetectable in platelets isolated from dengue patients; however, we observed an increase in CD14+CD16+ monocyte-platelet complexes, suggesting a mechanism for platelet clearance.

Semicrystalline Long-Chain Polyphosphoesters from Polyesterification

Semicrystalline aliphatic polyphosphoesters can be obtained in a one-step approach by polyesterification of readily available bio-based long-chain diols with dichlorophosphorus compounds. Nonadecane-1,19-diol and tricosane-1,23-diol with respectively methylphosphonic dichloride or phenyl dichlorophosphate yield polymers (PPE19Me, PPE23Me, PPE19(OPh), and PPE23(OPh)) with molecular weights Mn up to 3 × 104 g mol–1. DSC analysis of these polymers and a C12 analogue reveal significantly enhanced crystallinities and melting points (up to Tm = 87 °C) with increasing methylene sequence length. DMA on injection-molded samples shows glass transitions at −19 °C (PPE19Me) and −12 °C (PPE23Me). Single crystals of PPE19Me accommodate a single C19 repeat unit, as concluded from a lamella thickness of only 3 nm thick determined by AFM. Hydrolytic degradation of solid polymer samples under ambient conditions occurred only to a minimal extent over three months by hydrolysis of very small amounts of in-chain anhydride def...

Free Speech as a Special Right

Many theorists treat free speech as a special right. Other theorists argue that, in order for free speech to be important, it must be a special right, but they conclude that it is not. What the term “special right” means in these contexts, however, remains elusive. The term usually suggests that the right in question is distinguishable from the usual governmental decision making processes and from other rights. But just how distinctive the right must be, and in what ways, is rarely defined clearly. Indeed, many discussions of free speech assume quite demanding criteria for a special right of freedom of speech, even as these criteria remain incompletely articulated. This paper seeks to define the criteria for a special right. It argues that the idea of a special right actually conceals two separate requirements. First, a special right must be distinct, in that the activities covered by the right must be analytically distinguishable from the activities outside of it. Second, a special right must be robust in the protection it affords. Most theories demand that a free speech right be highly distinctive, if not singular, and that it receive highly robust protection. By contrast, this paper posits that distinctiveness is a requirement of a special right only to a minimal extent and robustness, as commonly understood, not at all. On the revised criteria offered here, it seems possible that speech may after all be special, though the free speech right we want may be different from the one we can have.

Modification of surgical procedure for "probable" limited dorsal myeloschisis.

OBJECTIVE Since the entity limited dorsal myeloschisis (LDM) was proposed, numerous confusing clinical cases have been renamed according to the embryopathogenesis. However, clinical application of this label appears to require some clarification with regard to pathology. There have been cases in which all criteria for the diagnosis of LDM were met except for the presence of a neural component in the stalk, an entity the authors call "probable" LDM. The present study was performed to meticulously review these cases and suggest that a modified surgical strategy using limited laminectomy is sufficient to achieve the surgical goal of untethering. METHODS The authors retrospectively reviewed the imaging findings, operative notes, and pathology reports of spinal dysraphism patients with subcutaneous stalk lesions who had presented to their institution between 2010 and 2014. RESULTS Among 33 patients with LDM, 13 had the typical nonsaccular lesions with simple subcutaneous stalks connecting the skin opening to the spinal cord. Four cases had "true" LDM meeting all criteria for diagnosis, including pathological confirmation of CNS tissue by immunohistochemical staining with glial fibrillary acidic protein. There were also 9 cases in which all clinical, imaging, and surgical findings were compatible with LDM, but the "neural" component in the resected stalk was not confirmed. For all the cases, limited exposure of the stalk was done and satisfactory untethering was achieved. CONCLUSIONS One can speculate based on the initial error of embryogenesis that if the entire stalk were traced to the point of insertion on the cord, the neural component would be proven. However, this would require an extended level of laminectomy/laminotomy, which may be unnecessary, at least with regard to the completeness of untethering. Therefore, the authors propose that for some selected cases of LDM, a minimal extent of laminectomy may suffice for untethering, although it may be insufficient for diagnosing a true LDM.

Incidence and Adverse Prognostic Implications of Histopathologic Organ Invasion in Primary Retroperitoneal Sarcoma

The incidence of histopathologic organ invasion (HOI) in retroperitoneal sarcoma (RPS) is not well described. We reviewed our experience to investigate the rate and prognostic implications of HOI. Patients with primary RPS who underwent surgery at our institution were reviewed. Histopathologic organ invasion was defined as microscopic organ invasion confirmed by re-review of pathology slides by an expert sarcoma pathologist. Impact of HOI on the crude cumulative incidence of locoregional recurrence, distant recurrence, and overall survival rates was analyzed. Between 2002 and 2011, one hundred and eighteen patients underwent resection for primary RPS; 99 had at least 1 organ resected and, among those, HOI was present in 58% (57 of 99). Among the 77 patients with the 3 most common histologies, rates of HOI were 61% for dedifferentiated liposarcoma, 56% for leiomyosarcoma, and 40% for well-differentiated liposarcoma. In this subset, HOI was associated with no difference in 2-year crude cumulative incidence of locoregional recurrence (48% vs 47%; p= 0.55) or distant recurrence (46% vs 22%; p= 0.2). With a median follow-up of 33.6 months, HOI was an independent predictor of worse 5-year overall survival (34% vs 62%; p= 0.04; hazard ratio= 2.3; 95% CI 1.2 to 4.4; p= 0.02). The likelihood of organ invasion can be predicted by histologic subtype of primary RPS. To the best of our knowledge, this is the first study to demonstrate that HOI is associated with worse overall survival. These data can help guide the minimal extent of surgical resection required for RPS.

The practice of minimal access surgery in Nigeria. Challenges and prospect

Background: There is increasing enthusiasm in the acquisition of skills in minimal access surgery MAS in Nigeria.Objectives: This study was therefore conducted to assess the extent of practice of MAS in 25 Federal and State Teaching Hospitals TH and 22 Federal Medical Centres FMC in Nigeria,the challenges faced and the prospect for it.Methods: This was a prospective descriptive longitudinal study. A stepwise multistage cluster sampling technique was adopted whereby questionnaires were distributed to consultant delegates at the November 2015 SOGON Conference in Abuja and at the Benin Fetal Medicine Workshop in 2016. Data was analysed using the statistical package SPSS- 20.Results: The differences between the number of tertiary institutions that perform and those that do not perform diagnostic hysteroscopy was not statistically significant but it was statistically significant for diagnostic laparoscopy and dye test with more hospitals doing them (p = 0.001). Fewer institutions perform resection of endometrial polyps,endometrium,submucous fibroids,endometrial synechiae and septum,abdominal adhesiolysis, Salpingectomy,oophorectomy,cystectomy,myomectomy and hysterectomy (P = 0.001- 0.07 and 0.02-0.001 in FMC and TH respectively) with most of the differences been statistically significant. Endometrial ablation, incontinence and other major MAS were not performed in Nigerian tertiary centres.Conclusion: MAS has been partially introduced in Nigerian tertiary health institutions but there are enormous challenges to its expansion.Keywords: Practice, Minimal access surgery,Nigeria,Extent,Challenges and Prospect,

Minimizers and EVEN

Abstract It is widely acknowledged that polarity sensitivity pertains to the lexical nature of NPI minimizers, phrases denoting a minimal quantity, extent or degree. This paper, however, proposes that so-called “negative polarity” of Mandarin Chinese minimizers (yi-CL-N ‘one.CL+N’ and yidian-N ‘one.point N’) is not lexically determined, but is facilitated by utilizing the existing lian... dou ‘including... all’ EVEN construction. Specifically, total negation is decomposed into a scalar operator lian, which evokes a set of order ranked alternatives determined in context, and the maximizing/universal operator dou ‘all’ that quantifies over the contextual alternatives plus the focused minimizer, which is placed at the end of the scale. The scalar minimizer syntactically scopes over the negation to represent the logic of ∀¬. This paper further distinguishes minimizers from lexical NPI renhe ‘any’ with respect to (i) scoping out of the negation for the former, (ii) being irrelevant to the non-veridical licensing conditions that otherwise license any and NPI-renhe, (iii) a clausemate relation between dou and negation, and (iv) the lack of intervention effects of strong quantifiers between the minimizers and negation. The study lends further support to the claim that scalar EVEN is construed with minimizers. A comparison of Chinese minimizers with those in Hindi and Japanese has an implication for varieties of coding polarity ranging from purely lexical to syntactical means crosslinguistically.

Distal tibiofibular synostosis after surgically resolved ankle fractures: An epidemiological, clinical and morphological evaluation of a patient sample

IntroductionAnkle fractures comprise a highly morphologically and etiologically diverse group of injuries, which includes various degrees of impairment of bone and ligamentous structures. The complete synostosis and incomplete bony bridging of tibiofibular syndesmosis are among the local late complications after surgically treated ankle fractures. Patients and method269 patients were evaluated, including 203 patients with Weber type-B fractures, and 66 patients with Weber type-C fractures. All patients underwent ankle radiography at standard intervals (post-operatively, 6 and 12 weeks, 6 and 12 months). The final assessment one year after osteosynthesis was performed. The study analyzed age, sex, fracture morphology, the location and morphology of ossification, functional outcomes and subjective evaluations of patient status. ResultsAs risk factors there were found male sex, tibiotalar dislocation, syndesmotic screw fixation and Weber type-C fractures. The severity of subjective difficulties and objective status were not dependent on the size of distal tibiofibular synostosis. Discussion and conclusionDespite relatively extensive imaging findings of complete synostosis or incomplete bony bridging, they only limited functional outcomes to a minimal extent.

PP.06.12] POPULATION BASED STUDY OF HYPERTENSION IN HUNGARY- 2015. NATIONWIDE COMPREHENSIVE HEALTH SCREENING PROGRAM IN HUNGARY 2010–2015

Objective: The year 2015 saw the continuation of Hungary's greatest and to date most comprehensive health screening program started in 2010. Design and method: The examinations - among them coronary examinations - covered the fields of cardiology and hypertension, they took place in a specially furnished lorry. In the Program we measured blood pressure, pulse rate, calculated cardiovascular risk, plasma cholesterol, glucose and uric acid levels. Whole body analysis started with measuring height, weight, abdominal cirumference and waiste/hip ratio defining target body weight. Following the measurment of body fat and muscle content we decided the surface volume of the abdominal fat and calculated body mass index. Results: Participants and results of the examinations of the people who have presented themselves for the test sin 2015 (n = 23764) have been evaluated. In the Program a total (52.2%) women and (47.8%) men were tested at 204 locations. Upon data processing with the help of a query 19,3% of the participants reported suffering from hypertension (1291 women and 1263 men). In the past five years the screening truck has been to 1123 places is Hungary, and travelled 134112 km, 135879people have participated in comprehensive screening. In total 3 936325 examinations have been performe, The average systolic blood pressure among women was in the normal range up to the age of 55 years. The diastolic blood pressure levels were in the normal range for both sexes (with the exception of the age group 46–55 of men where it exceeded the upper limit of the normal range by a minimal extent). Among men stage 1 hypertension was the most frequent status for all age groups; blood pressures above 140/90 were measured for 39% of subjects from age 18 onwards. The distribution of this did not vary significantly with the increase of age. Conclusions: Conclusion: Thanks to the vast information obtained through the program a comprehensive picture has been drawn about Hungary's present health status not only on a regional or cross sectional level but as it was described in the program, too.

State-of-the-art technology on conservation of ancient roofs with timber structure

Abstract The timber load bearing structures of the roofs are organized as a hierarchic articulation of members and structural units connected by joints and auxiliary beams to form structural systems. The authors list, for everyone of the cited levels, the techniques that can be considered obsolete as the indiscriminate replacements of members and units or, worst, of the entire system, the application of heavy steel profiles placed at the exterior or at the interior of the members and of the units or the invasive prostheses that stiffen the nodes and destroy their ductility. Considerations on the lack of appropriateness of these techniques are exposed. Today are available new techniques that, both obtained as adjustment of the old ones or based on completely new approaches, are inspired by conservation and repair criteria. Since they are based on interventions of minimal extent, they are able to ensure, within certain limits, respect for the original structure with the values they carry and rescue of the original configuration, materials and bond. The authors non acceptance of the practice of dismantling the structure, to some extent or entirely, in order to replace its damaged parts demands for working in situ thus allowing also the rescue of the original assembly.

Conceiving Corporate Governance for an Asian Environment

Most Asian corporations are vehicles used by a separate system or social network – such as a family, a state or a political party. The challenges presented by the corporation operating as a system within a system are in most instances ignored. The dominant model of corporate governance understands the company as a collection of otherwise unrelated individuals united for the sole purpose of profit. It recognizes the systematic environments in which corporations exist only to the minimal extent necessary to check and punish conflicts of interests, assess compliance with duties or determine whether dominant behavior is unfair. At most, social networks like families are recognized as potential sources of power and information asymmetries that exploit other corporate constituencies. This ignores a deep body of empirical scholarship demonstrating the advantages enjoyed by family enterprises – from profitability and longevity to lower executive compensation and transaction costs. This paper uses institutional and systems theory tools to begin development of a model of corporate governance dynamics that takes real account of the systems that coexist with the corporate vehicle, using the initial examples of the family and the political party. The paper formulates “structural couplings” (Luhmann) through which value systems can meaningfully communicate with the governance systems of the corporation.

Consequences of tidal interaction between disks and orbiting protoplanets for the evolution of multi-planet systems with architecture resembling that of Kepler 444

We study orbital evolution of multi-planet systems with masses in the terrestrial planet regime induced through tidal interaction with a protoplanetary disk assuming that this is the dominant mechanism for producing orbital migration and circularization. We develop a simple analytic model for a system that maintains consecutive pairs in resonance while undergoing orbital circularization and migration. Migration times for each planet may be estimated once planet masses, circularization times and the migration time for the innermost planet are given. We applied it to a model system with the current architecture of Kepler 444 interacting with a protoplanetary disk, the evolution time for the system as a whole being comparable to current protoplanetary disk lifetimes. In addition we performed numerical simulations with input data obtained from this model. These indicate that although the analytic model is inexact, relatively small corrections to estimated migration rates yield systems for which period ratios vary by a minimal extent. Because of relatively large deviations from exact resonance in the observed system of up to $2\%,$ the migration times obtained in this way indicate only weak convergent migration such that a system for which the planets did not interact would contract by only $\sim 1\%$ although undergoing significant inward migration as a whole. We performed additional simulations to investigate how the system could undergo significant convergent migration before reaching its final state. These indicate migration times have to be significantly shorter and resonances significantly closer. Relative migration rates would then have to decrease allowing period ratios to increase to become more distant from resonances as the system approached its final state in the inner regions of the protoplanetary disk (abridged).