Discovery of Reflection Nebulosity Around Five Vega-like Stars

Coronagraphic optical observations of six Vega-like stars reveal reflection nebulosities, five of which were previously unknown. The nebulosities illuminated by HD 4881, HD 23362, HD 23680, HD 26676, and HD 49662 resemble that of the Pleiades, indicating an interstellar origin for dust grains. The reflection nebulosity around HD 123160 has a double-arm morphology, but no disk-like feature is seen as close as 2.5 arcsec from the star in K-band adaptive optics data. We demonstrate that uniform density dust clouds surrounding HD 23362, HD 23680 and HD 123160 can account for the observed 12-100 micron spectral energy distributions. For HD 4881, HD 26676, and HD 49662 an additional emission source, such as from a circumstellar disk or non-equilibrium grain heating, is required to fit the 12-25 micron data. These results indicate that in some cases, particularly for Vega-like stars located beyond the Local Bubble (>100 pc), the dust responsible for excess thermal emission may originate from the interstellar medium rather than from a planetary debris system.Comment: The Astrophysical Journal, in press for March, 2002 (32 pages, 13 figures

Vector wind, horizontal divergence, wind stress and wind stress curl from SEASAT-SASS at one degree resolution

Conventional data obtained in 1983 are contrasted with SEASAT-A scatterometer and scanning multichannel microwave radiometer (SMMR) data to show how observations at a single station can be extended to an area of about 150,000 square km by means of remotely sensed data obtained in nine minutes. Superobservations at a one degree resolution for the vector winds were estimated along with their standard deviations. From these superobservations, the horizontal divergence, vector wind stress, and the curl of the wind stress can be found. Weather forecasting theory is discussed and meteorological charts of the North Pacific Ocean are presented. Synoptic meteorology as a technique is examined

The Project Method in Laboratory Psychology

Of course every experiment is a project, literally, but usually there are two outstanding weaknesses. One is the failure to connect the study closely with other courses and to bring general lecture and text-book material to bear upon the experiments. The other is the tendency to follow directions literally with eyes and hands, with but little real cerebration

Some Standardizing Tests of Stern\u27s Tone Variator

The tone variator is a closed-tube sound producing instrument. It consists of a cylindrical brass bottle, the bottom of which is a piston controlled by a delicate cog-wheel mechanism. By means of this the depth of the bottle may be readily changed, thus varying the pitch. The sound is produced by a stream of air directed across the mouth of the bottle through a tube set at the proper angle. A pointer attached to the piston’s setting gear indicates the pitch in terms of vibrations per second

A Bilingual Thesaurus of Everyday Life in Medieval England: Some Issues at the Interface of Semantics and Lexicography

This paper reports on issues at the interface between semantics and lexicography that arose out of the data collection and classification of vocabulary in Anglo-Norman and Middle English in order to create a bilingual thesaurus of everyday life in medieval England. The Bilingual Thesaurus project is based at Birmingham City University and the University of Westminster. Issues to be resolved included the definition of an occupational domain; the creation of a methodology of data collection; the delimitation of domain-specific vocabulary; making distinctions between sense and usage; and the categorisation of the lexical items. Some of these issues are general to thesaurus-making, some are specific to the making of historical thesauruses, while some are unique to the production of a thesaurus of two languages whose use overlapped for several centuries in the late medieval period in England

Lexical Borrowing in the Middle English period: A multi-domain analysis of semantic outcomes

The Middle English period is well known as one of widespread lexical borrowing from French and Latin, and scholarly accounts traditionally assume that this influx of loanwords caused many native terms to shift in sense or to drop out of use entirely. The study analyses an extensive dataset, tracking patterns in lexical retention, replacement and semantic change, and comparing long-term outcomes for both native and non-native words. Our results challenge the conventional view of competition between existing terms and foreign incomers. They show that there were far fewer instances of relexification, and far more of synonymy, during the Middle English period than might have been expected. When retention rates for words first attested between 1100-1500 are compared, it is loanwords, not native terms, which are more likely to become obsolete at any point up to the nineteenth century. Furthermore, proportions of outcomes involving narrowing and broadening (often considered common outcomes following the arrival of a co-hyponym in a semantic space) were low in the Middle English period, regardless of language of origin

Synoptic scale wind field properties from the SEASAT SASS

Dealiased SEASAT SEASAT A Scatterometer System SASS vector winds obtained during the Gulf Of Alaska SEASAT Experiment GOASEX program are processed to obtain superobservations centered on a one degree by one degree grid. The grid. The results provide values for the combined effects of mesoscale variability and communication noise on the individual SASS winds. These superobservations winds are then processed further to obtain estimates of synoptic scale vector winds stress fields, the horizontal divergence of the wind, the curl of the wind stress and the vertical velocity at 200 m above the sea surface, each with appropriate standard deviations of the estimates for each grid point value. They also explain the concentration of water vapor, liquid water and precipitation found by means of the SMMR Scanning Multichannel Microwave Radiometer at fronts and occlusions in terms of strong warm, moist air advection in the warm air sector accompanied by convergence in the friction layer. Their quality is far superior to that of analyses based on conventional data, which are shown to yield many inconsistencies

Lone other-language items in later medieval texts

This paper addresses the use in medieval texts of ‘lone other-language items’ (Poplack and Dion 2012), considering their status as loans or code-switches (Durkin 2014; Schendl and Wright 2011). French-origin and English-origin lexemes in Middle English, respectively, were taken from the Bilingual Thesaurus of Everyday Life in Medieval England, a source of loan words chosen for its sociolinguistic representativeness and studied via Middle English Dictionary citations and textbase occurrences. Four criteria were applied for whether they should be treated as code-switches or as loans: the textual context in which the item appears, the adoption of target language verbal morphology, the length of attestation within the target language of individual lexical items (Matras 2009), and the integration of items into the syntactic structure of nominal phrases in conflict sites for code-switching (Poplack et al. 2015). Results provide little support for code-switching as the channel for the integration of lone other-language items, suggesting rather that individual items of foreign origin were immediately borrowed, consistently with Poplack and Dion’s (2012) treatment of contemporary contact phenomena

Halting Planet Migration in the Evacuated Centers of Protoplanetary Disks

Precise Doppler searches for extrasolar planets find a surfeit of planets with orbital periods of 3-4 days, and no planets with orbital periods less than 3 days. The circumstellar distance, R_0, where small grains in a protoplanetary disk reach sublimation temperature (~1500 K) corresponds to a period of ~6 days. Interior to R_0, turbulent accretion due to magneto-rotational instability may evacuate the disk center. We suggest that planets with orbital periods of 3-4 days are so common because migrating planets halt once this evacuated region contains the sites of their exterior 2:1 Lindblad resonances.Comment: 9 pages, 1 figure, to appear in ApJ letter